US 20070220776 A1
A laundry appliance includes a cabinet or surround structure. A pair of front feet are respectively provided at either front corner thereof. A front unit includes a front face, a pair of side face portions extending rearwardly therefrom to abut the side walls of the cabinet, and a pair of spaced apart front feet portions which are adjacent front feet of the cabinet. A top deck, held down by a securement, includes a flange surrounding or substantially surrounding an upper edge of the front panel and the side and rear walls of the cabinet. A connection, which is releasable by vertical relative movement of the front panel, is provided between each front foot portion of the front panel and a front foot of the cabinet.
1. A laundry appliance including:
a cabinet or surround structure including a rear wall, a pair of side walls extending forward from said rear wall and connected with said rear wall along adjoining edges and a base member connected with said side walls,
a pair of front feet respectively at either front corner of said cabinet,
a front unit including a front face, a pair of rearwardly turned side face portions, connected with said front face along their forward edges and extending rearwardly from said edges to abut the front edges of said side walls of said cabinet and a pair of spaced apart front feet portions, positioned to be adjacent said front feet of said cabinet,
a top deck including a downwardly extending perimeter flange surrounding or substantially surrounding an upper edge of said front panel, side walls and rear wall, and a securement holding down said top deck, and
a connection between each said front foot portion of said front panel and a front foot of said cabinet, said connection releasable by vertical relative movement of said front panel.
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This application is a divisional of U.S. patent application Ser. No. 10/962,948, entitled “A Laundry Appliance”, filed Oct. 12, 2004 which is a divisional of PCT/NZ03/00065, filed on Apr. 10, 2003. U.S. patent application Ser. No. 10/962,948 and PCT/NZ03/00065 are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to laundry appliances and in particular consumer laundry appliances for the drying of damp textile articles, such as items of clothing, towels and bed linen.
2. Summary of the Prior Art
Prior art clothes drying machines are generally of a type having a rotatable metal drum supported within a rectangular cabinet. The rotatable drum includes an open end facing the front of the cabinet and a substantially closed end at the rear of the cabinet. Access is gained to the open end of the drum by opening a door or hatch on the front face of the cabinet.
The prior art clothes dryer has a significant ergonomic disadvantage to a top loading laundry appliance. It is a particular disadvantage when washing has to be transferred from a top loading clothes washing machine to a front loading clothes dryer.
U.S. Pat. No. 3,514,867 describes a drum type clothes dryer including a belt tensioning arrangement enabling reversal.
JP 2-274294 describes an automatic door opening and closing arrangement for a rotary drum which requires stopping the drum at a rotary position for operating a door stopper provided on the drum door. Operation of the door stopper into an engagement released state also brings the drum door into a non-movable state relative to the cabinet.
WO 0028127 describes a laundry appliance including a rotating cylindrical drum with a hatch forming part of the cylindrical surface. The drum is stopped to allow disengagement of the hatch from the drum and engagement relative to the cabinet at the commencement of an opening operation. It is also stopped for the reversed process at the end of a closing operation.
U.S. Pat. No. 5,678,430 describes a top loading automatic washer with the drum provided to rotate on a horizontal axis. The laundry carrying drum has a hinged opening and is retained within a water collection tub with a spring loaded flexible sliding tub door.
EP 483909 describes a device for halting the drum of a top loading horizontal axis laundry machine in a loading and unloading position.
FR 2478151 describes a drum and hatch construction for a top loading horizontal axis washing machine.
WO 00/28126 describes a top loading horizontal axis washing machine wherein user access to the drum is provided by moving the drum at least partially out of a surrounding cabinet to expose an access opening. Rocking, pivoting and sliding arrangements are described.
U.S. Pat. No. 4,262,870 describes a retractable self levelling assembly for supporting a laundry appliance. The assembly has two spaced apart upwardly and outwardly angled slots for slidably receiving pins which connect supporting feet to opposite ends of an adjustable tension bar.
U.S. Pat. No. 4,949,923 describes a self levelling assembly for an appliance with legs slidably received through channels for vertical movement. Each leg is provided with outwardly extending pins engaged within upwardly converging slots of a stabiliser bar.
U.S. Pat. No. 3,954,241 describes a self adjusting levelling assembly for an appliance with includes a pair of mounting brackets each provided with a vertically shiftable, floor engaging leg member. The leg members are interconnected by a cable such that they are free to shift vertically relative to their corresponding brackets in a reciprocal relationship when not supporting a normal proportional share of the weight of the appliance.
U.S. Pat. No. 4,770,275 describes a leveller for a ladder which has a pair of sliding legs telescopically engaged in respect of upright tubes. A wire rope is fixed to upper regions of the legs and extends between the tubes. The wire is engaged with a support guide fixed relative to the ladder structure.
U.S. Pat. No. 3,991,962 describes a self levelling mechanism for an appliance cabinet which includes a polypropylene foot at each corner of the cabinet. Each foot is interconnected by a continuous cable for vertical movement in unison relative to the cabinet and to each other. A locking wedge is provided for each foot for locking each foot in fixed relation with the cabinet.
WO 95/08016 describes a bulk lint collector for a clothes dryer. An annular lint filter rotating with the dryer drum extends from one end of the drum and encircles the dryer door. Lint is collected in a cavity in the dryer door and removable by removing an outer face panel of the door.
It is an object of the present invention to provide a laundry drying appliance and or associated parts and or associated methods which at least go some way towards overcoming disadvantages of the prior art or which will at least provide the public with the useful choice.
In a first aspect the invention may broadly be said to consist in a clothes drying appliance including:
a cabinet or surround structure, including an attachment for a removable front panel,
a drum support structure supporting said drum for rotation,
a drive motor with a drive pulley,
a belt passing around said drive pulley of said drive motor and around said drum for driving rotation of said drum in a direction dependant on the direction of rotation of said motor, and
a belt tensioning device including a pair of spaced apart tensioning pulleys, each having an axis of rotation substantially parallel with the axis of rotation of said drive pulley, with the line between the centres of said tensioning pulleys separating said drive pulley from said drum, said tensioning pulleys spaced sufficiently close to impinge upon the path of said belt passing around said pulley and said drum, and a biasing agent pressing said pulleys toward said drum.
In a further aspect the invention may broadly be said to consist in a laundry appliance including:
a cabinet or surround structure including a rear wall and a pair of side walls extending forward from said rear wall and connected with said rear wall along adjoining edges and a base member connected with said side walls,
a front panel including a front face and pair of rearwardly turned side face portions, connected with said front face along their forward edges and extending rearwardly from said edges to abut the front edges of said side walls of said cabinet,
a locating engagement between each said butting forward edge of said side wall and rear edge of said side face portion,
a locating engagement between the lower rear edge of said front panel and the lower front edge of said surround structure,
a top deck including a downwardly extending perimeter flange surrounding or substantially surrounding an upper edge of said front panel, side walls and rear wall, and a securement holding down said top deck.
To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.
The drum 104 is supported horizontally within the cabinet 101 from its ends 105 and 110. Each drum end is supported on a chassis. In the preferred form, and in accordance with one of the inventions herein, the chassis is moved forward from the cabinet 101 with the front of the cabinet removed. In the preferred form described and illustrated movement of the chassis from the cabinet, together with the drum and other mechanical assemblies, is by a pivoting movement around a pivot axis adjacent the lower front edge of the cabinet. However other movement interfaces may be adopted including a rocker interface or sliding interface. For example a rocker interface may take the form of two or more downwardly extending curved rockers rolling on appropriate tracks supported on the base panel. A sliding interface may include two or more supporting telescopic rail supporting the chassis side panels.
Provision of a movement interface to allow for movement of the chassis subassembly out of the cabinet is not a necessary feature of dryers according to many of the inventions herein which are equally applicable to dryers where the subassembly is fixed within the cabinet. By way of example only, drum opening and closing, mechanical drive, lint collection, self levelling feet, drum opening and closing and actuation thereof are all aspects of the present dryer which can operate independently and be incorporated into laundry machines of other type and form without departing from the intended scope of the respective invention.
The preferred chassis includes a pair of side panels 522 and 622, preferably formed of sheet metal and having rolled edges 400 turned inwards to form a stiffening flange around its perimeter. Connecting beams 402, 404 and 406 extend between the chassis side panels 522 and 622 below the level of the drum 104. The connecting beams may be formed from pressed or folded sheet metal and to a profile having appropriate stiffness properties. The beams may be secured at their ends to the panels 522 and 622 in any appropriate manner. For example, the foremost beam 402 may be secured to a turned in flange 401 along the forward edge of the panels by resistance welding or fasteners, the rear most beam 404 may be similarly secured and the intervening beam 406 may be fastened by way of brackets or resistance welded folded tabs.
Referring now also to
The particular form of the load bearing surfaces of the foot is not critical. It is important that the structure is sufficiently strong to locate the drum support structure in use and during transport. The arrangement illustrated in
The lower edge of the removable front unit 470 includes a front foot portion 472 adjacent each side wall portion thereof. Each front foot portion 472 includes a rearwardly extending locking member 700 including a downwardly extending locking tongue 701. Tongue 701 engages behind a front wall 484 of the respective front foot 102. Lateral rear wall 703 of the locking member 700 fits within recesses 704 of the front foot load bearing members 422. The upper edge of wall 703 engages under a downwardly facing ledge 490 defining the upper boundary of recess 704. Full engagement of locking member 701 with the foot 102 requires a small rearward pivoting of the front panel unit 470 about its foot connection with the reminder of the cabinet. Disengagement requires a small forward pivoting. This pivoting may be accomplished by a slight lifting, but is otherwise inhibited by the surface supporting of the front of the cabinet in the vicinity of the join. Slight lifting of the front of the cabinet allows relative pivoting of the feet.
An alternative foot arrangement which includes an alternative form of support of the side chassis panel is illustrated in FIGS. 25 to 28. In this arrangement the side chassis is provided with a plastic stiffening member 2802 extending along its lower edge. The stiffening member is connected to the lower edge of the panel, preferably clipping in place and being further secured by fasteners. The front end of the stiffening member 2802 includes a bearing surface 2800 to bear on upstand walls 2804. The upstand walls 2804 pass upwardly through an aperture 2810 in base panel 2808. An engagement extension 2806 passes upward through the base panel 2808 through another aperture 2812. The engagement extension 2808 and the upstand 2804 each extend beyond the bound of the respective aperture, in opposite directions. The upstand, including walls 2804 and connecting lateral bracing, is a separate component from pedestal 2814. Engagement extension 2806 is integral with pedestal 2814.
In connecting the foot to the base panel, the engagement extension 2806 is passed through its respective aperture 2812 and the pedestal 2814 is pivoted up to a position against the under face of base panel 2808. The upstand component is inserted through its aperture 2810 from above and clips into the pedestal component 2814. The leading edge 2816 of the upstand component overhangs the leading edge 2818 of the pedestal component 2814 leaving a recess 2820 for receiving the rearward edges of the front foot portions of the removable front unit. Apertures 2820 in the upper surface of the forward portion of pedestal component 2814 are exposed in the recess 2820 for receiving the locking tongues of the removal front unit.
The stiffening member 2802 may be attached to the chassis side panels in any convenient fashion. In the form illustrated in FIGS. 25 to 28 it engages with the stiffening member 2802 by a clip arrangement at its forward end and a fastener at its rearward end, with the side panel and stiffening member each configured so that the side panel bears on the stiffening member along most of its length. At the forward end turned in flange 2840 sits in a trough 2842 behind an upstand 2846. A projection 2844 from upstand 2846 extends through an aperture 2848 in the flange 2840. Turned in flange 2850 along the lower edge of the side panel sits on a longitudinal rail 2860 of the stiffening member 2802. The flange 2850 includes a downwardly turned edge 2852 to provide lateral support from one direction. Relative to the turned down edge 2852 the panel extends behind a forward upstand portion 2854 and a rear upstand portion 2856 of the stiffening member 2802, to provide lateral support in the other direction. A turned in flange 2858 on the rearward edge of the side panel sits in a trough 2862 formed by an outward and upward projection 2864 of rear upstand 2856. A fastener inserted through hole 2866 secures the side panel in position on the stiffening member 2802.
An alternative form of rear foot, illustrated in FIGS. 25 to 27 includes a foot arrangement which provides for automatic levelling. The arrangement includes a first socket 2500 connected with the cabinet adjacent one side and a second socket connected with the cabinet, adjacent the other side. The first socket is provided in association with one rear foot assembly, the second socket is provided associated with the other rear foot assembly. A foot 2504 downwardly protrudes from each socket. The foot is moveable along an axis into and out of the socket.
A non-extensile band 2506, fixed at one end 2508 relative to the first socket, passes through the first socket, including over an upper bearing surface 2510 of the first foot. The band passes across the back of the cabinet, adjacent the base panel 2512 and through the second socket, including over an upper bearing surface of the second foot, and is fixed at its other end relative to the second socket.
Each foot 2504 includes a retaining tongue 2514 spaced above the upper bearing surface.
Each socket includes a downward bearing surface 2516 at least in the region where the band passes out of the respective socket towards the other socket.
Each socket is formed within an internal upstand component 2518, and within an external pedestal component 2520. The internal upstand component and the pedestal component are mutually engaged with the base panel 2512 of said appliance therebetween the foot passes into the upstand member through an aperture in the base panel.
The upstand member includes a band engagement (such as 2522 in
The restraining force applied to each foot by the band is balanced laterally due to the band passing fully over the foot and being secured to the non-moving structure. Force in a fore and after direction is substantially balanced due to the use of a non-extensile metal band of much greater width than thickness, as opposed to a wire or other low aspect ratio alternative. With its width the metal band provides a distributed load on the bearing surfaces of the feet and the sockets so as not to bite into the material from which these surfaces are formed. This allows these components to be manufactured from suitable plastics.
Referring particularly to
For maintenance of the internal dryer components the top deck may be released from the upper edge of the cabinet by removing the associated fastenings. With the top deck released its front portion may be tilted up to disengage from the upwardly extending flange of the front unit. The front feet engagement may be released by lifting the front portion of the dryer and pivoting the front unit forward. The front unit is now completely removable from the remainder of the cabinet while the top deck is tilted up. With the front unit removed electrical connections between the components carried by the supporting chassis and the top deck may be broken and the entire drum and supporting chassis may be pivoted from the cabinet, with the bearing surfaces of the lower front corners of the chassis side walls sliding over the complimentary bearing edges of the upwardly extending front foot bearing walls. The chassis carries the drum, motor, fan and drive pulley assemblies and presents these components to the maintenance person in front of the cabinet. The heater component, whether gas or electric, is secured to the base panel and is available for inspection and maintenance with the drum and supporting chassis in its more usual operating position once the front unit has been removed.
Referring to FIGS. 1 to 3 and 34 the cylindrical drum 104 has a pair of circular drum ends and a cylindrical drum skin connecting therebetween. The cylindrical drum skin is made up of a first part-cylindrical skin 107 connected permanently with the drum ends 105, 110 and a part-cylindrical drum hatch 108 whose edges slide within a pair of circumferential tracks 109 defining the side edges of a drum opening. The permanently connected drum skin portion 107 is supported by vanes 106, 186 and 196 as well as by its permanent connection to the drum ends. The vanes 106, 186 and 196 each span between the drum ends and are connected with both the drum ends and the drum skin. The tracks 109 are provided on a drum end support member 3400 connected to the periphery of the drum around that part of the circumference that defines the drum opening. The vanes 186 and 196 connect between the ends of the drum end support members. The vanes 186 and 196 form front and back edges of the drum opening. Together, the vanes 186 and 196 and the drum end support members 3400 define the drum opening.
The drum 104 is rotatably supported within the cabinet 101 by a spindle at one end and an annular bearing surface at the other end.
The hot air inlet manifold 2410 is secured to the inlet end tilt out chassis 522. The hot air inlet manifold comprises an inner side pressed plate 520 and an outer side pressed plate 521, secured together and to the chassis 522 around the perimeter 531. The perimeter may be secured together and to the chassis 522 for example by fasteners or resistance welding. The inner side plate 520 includes hot gases outlet openings 523 which are adjacent the perforated central portion 500 of drum end 110 when assembled. Openings 523, 524 are spaced around a central hub portion 535 of the plate 520, leaving spokes intact supporting the central hub region 535.
The outer plate 521 includes a depressed central region 530 with an aperture 540 therethrough. The depressed region 530 accommodates the head of a bolt 508 when assembled. The inner plate 520 includes an aperture 541 aligned with aperture 540 of outer plate 521. A compression tube 536 is located between the inner and outer plates 520, 521 to maintain the separation between the plates 520 and 521 in the vicinity of apertures 541 and 540 respectively. A bearing shaft 511 has a locating spigot 555 fitted within compression tube 536 through aperture 541. The bearing shaft includes a thrust receiving flange 550 located against the outer surface of central portion 535 of the inner plate 520. An outer end face of the spherical drum bearing 510 bears against the other side of thrust flange 550. The bearing shaft 511 includes a stub shaft 560 extending into the drum. The stub shaft 560 fits within an inner bore of the spherical bearing 510.
The bearing shaft 511 includes a central axial bore 561 for receiving bolts 508 and 562 which complete the assembly. Bolt 508 passes through aperture 540 and the bore of the compression tube 536 to be secured within one end of the central bore 562 of bearing shaft 511. This leaves the stub shaft protruding from the inner sheet 520 of the hot gases manifold. With the spherical bearing 510 fitted over the stub shaft 560 a protective cap 563 is secured to the end of stub shaft 560 by a bolt 562. The protective cap 563 covers the flat hub region of the drum end and associated bearing holder 505 and fasteners 506. The bolt 562 secures against a flat and central hub of the cover 563. The flat and central hub of cover 563 extends beyond the end face of the stub shaft 560 to retain the spherical bearing 510 on the stub shaft.
An annular seal is created between the drum end and the inner plate 520 of the hot gases inlet manifold by an annular seal 525 located about the circumference of the inlet openings 523, 524. The soft felt seal 525 is fixed to the drum facing surface of inner plate 520. The drum end 110 has an inwardly dished ring 501 concentrically outside the dished central region 500, leaving an outwardly facing annular ridge 526 therebetween. The outwardly facing annular ridge 526 presses into the felt seal 525 to provide an annular seal between the manifold and the drum end 110.
According to an alternative embodiment illustrated in FIGS. 36 to 38 the annular sliding seal at the drum inlet includes a resilient elastomeric support member 3600. The support member 3600 is substantially constant cross section having a base leg 3602 and a flexion leg 3604. A felt strip 3606 is secured to the flexion leg 3604 and the base leg 3602 is connected with the inlet duct. In place such as illustrated in
The resilient member 3600 includes protruding lugs 3608, which secure the base leg 3602 to the inlet duct by extending through apertures in a supporting panel of the inlet duct. The support member may be manufactured by extruding a constant cross section profile including the profile of protruding lug 3608, and removing longitudinal sections of the lug portion of the profile to leave protruding lugs 3608 at intervals along the strip. The strip may be extruded from known elastomers, such as Silicone.
Support of the drum at its outlet end and further detail of the drum air outlet can be seen with reference to
The lint collecting container 130 preferably includes an upper portion 650 and a lower portion 651. The upper portion 650 includes a handle element 652 moulded therein. The lower portion 651 is preferably formed of a clear or see through plastic material. The lower portion 651 includes a locating groove 653 to engage with a retaining ridge 654 of a housing 655 when in place. The upper portion 650 is held in place in the housing 655 by a resilient engagement of detents 660 in its lateral side walls 661 with cooperating protrusions in the housing.
The lint collector 130 is open at its upper end to receive lint peeled from an annular lint receiving surface 123 by a fixed position scraper 662. Lint falls from scraper 662 through the upper opening of the lint collector 130.
The annular lint receiving surface 123 extends axially from the outer face of domed ring 165 at its inner edge, and rotates with the drum. The lint receiving surface 123 is supported on a ladder frame 670 which has a pair of spaced apart ring members with laterally extending rungs spanning therebetween at intervals around its circumference. The form of supporting structure 670 is illustrated in
A pair of horizontal electrodes 683 are also fixed with the stationary central portion 131. The electrodes 683 are utilised in the dryer controller for sensing conductivity of the clothes load, and thereby the associated moisture content.
The annular lint filter 123 surrounds the stationary portion 131, and in turn is surrounded by an exhaust gases outlet manifold housing 603. The exhaust gases outlet manifold housing 603 is fixed to the inner face of the outlet end chassis 622 by suitable fasteners. The manifold housing 603 may for example comprise a plastic moulding, which forms an annular manifold chamber 605 in combination with the chassis 622. The annular chamber 605 exits to an outlet duct 606 at its lower end which in turn leads to a lateral outlet duct 124 connected with the fan housing 120.
The annular manifold 605 is enclosed between the manifold housing 603 and a manifold housing supporting part 741 fixed to the chassis plate 622. The manifold housing 603 includes a generally cylindrical portion 751 whose outer surface is generally parallel with the inner surface of cylindrical portion 730 of stainless steel drum end 726. The generally cylindrical portion 751 of the manifold housing 603 has a radially inwardly extending flange 752 extending from its open end, principally providing reinforcement and rigidly to the open end. The generally cylindrical portion 751 includes a plurality of receiving slots 753, extending from its corner with the flange 752, toward the supporting member 741. The slots 753 are spaced around the circumference of the cylindrical portion 751 and each receive a plastic bearing insert 681. The plastic bearing inserts 681 may be formed from any suitable hard wearing low friction material, for example TEFLON impregnated polyethylene.
An annular sealing strip 680 is also provided in the space between the cylindrical portion 730 of the drum end 726 and the cylindrical portion 751 of the housing 603. The sealing strip 680 may for example be a felt strip adhered to the outer surface of the cylindrical portion 751 of the housing 603, typically partially compressed to fit in the space between the two surfaces.
The plastic bearing inserts 681 preferably extend beyond the face of the flange 752 to at least partially butt the corner between cylindrical portion 730 and inwardly turned flange 750 of the drum end 726 and/or the face of the flange 750. The inserts 681 thus provide both radial and thrust bearing surfaces for the drum end against the perimeter of the outlet manifold housing 603.
An additional annular seal 682 is provided between the outer ring member 720 of the lint filter 123 and the housing supporting member 741. The housing supporting member 741 includes an annular inward step forming a substantially cylindrical radially outwardly facing surface 740, facing the radially inwardly facing surface 725 of the ring member 720. The annular seal 682, for example, a felt strip, is secured to the face 725 of ring member, for example by an adhesive. The strip is preferably lightly compressed in fitting between the surfaces 725 and 740.
According to an alternative form illustrated in
The retainer channel 3504 for the seal between the drum end and the duct is located in the outer face of the outlet duct. The retainer channel 3506 for the seal between the filter screen and the outlet duct is located in annular support member 3510 of the filter screen.
The retainer channel 3504 is located so that the felt strip of the seal between the drum end and the outlet duct fits within the space between an annular corner 3520 of said outlet duct and an annular corner 3522 of the drum end and extends around this corner.
The annular manifold chamber 605 is thus defined by fixed components carried by the chassis 622 (the manifold housing 603 and manifold housing supporting member 741) and rotating components of the drum end (including lint filter 123 with associated supporting structure, facia 165 and drum end 726, with the seal being maintained between the stationary and rotating components by annular seals 680 and 682. The lint collecting container 130 and perforated air inlet panel 131 and associated supporting assemblies are in effect disposed within the drum, backing on to the manifold supporting member 741 and surrounded by the lint filter 123.
A heater is located in the air inlet duct. The heater may comprise either a gas heater arrangement or an electrical heating coil arrangement, both of known type. Operation of the heating unit, whether of gas or electric type is controlled by an electronic control module 139.
Electronic control module 139 also controls the energisation of the drive motor for the drum and fan as will be described later in this specification. Motor speed control may, for example, be by PWM duty cycle control, on mains supply or by inverter frequency control of a rectified supply. The latter is preferred due to improved speed control and lower belt loads during reversal.
Air exiting drum 104 passes through the annular lint filter screen 123 of substantially cylindrical form and extending from the drum end 105. The air flow passes outward through the lint filter screen 123, depositing a lint layer on the internal surface of the screen. The manifold housing support 741 supports the perforated air outlet facia 122 which in turn supports the bulk lint collecting container 130 within a central aperture 131 of drum end 105. A scraper which forms part of bulk lint collecting container 130 (or alternatively supported directly by the air outlet duct) peels entrained lint from the surface of lint collecting screen 123 to fall through an opening in the top end of container 130 and collect within the container 130. The container 130 is removable from within the drum for emptying.
The air outlet end arrangement as described is the preferred form. However a comparatively simple conventional configuration might also be adopted.
For example a bearing assembly similar to that at the air inlet end of the drum could be used, with a lint filter screen provided covering the perforated air outlet, a protecting cover to guard the filter screen from the tumbling dryer load.
Motor Drive Assembly and Belt Tensioner
One preferred motor drive assembly and belt tensioner will be described with reference to
The motor well 1826 preferably includes an aperture 1830 to elevate heat build up from the motor 1800. The motor 1800 includes a resilient mount 1831 at each end with the respective shaft portion 1833 and 1835 passing out through the resilient mount. The resilient mounts are connected with the motor housing and are non-rotating relative to the housing. The motor well 1826 has a pair of end walls 1832. Each end wall includes a semi-circular recess 8037, 1839 for receiving the respective resilient mounting of the motor. Motor mounting is completed by securing a mounting cover 1834 over each of the resilient mountings. The mounting covers 1834 have a second substantially semi circular recess such that with the covers 1834 engaged and secured with the end walls 1832 the resilient mountings of the motor are pressed and held by the semi circular recesses.
Prior to assembly of the motor to the motor support bracket 1812 a fan 1806 is secured to one projecting shaft 1833 and a drive pulley to the other shaft 1835. Once the motor is assembled with the motor bracket 1812, a lower half 1836 of fan housing 120 is secured to the motor bracket 1812 to substantially enclose the squirrel cage fan 1806. Referring to
With the supporting chassis rocked back into the cabinet the rearward and downward pressing of the combination of flange 1840 and upstand wall 1842 improves the sealing around the lower edge of opening 1838. A complimentary upstand wall 1847 from the surrounding flange of outlet port component 1844 partly extends to opening 1838 to improve the sealing of the upper portion of the connection. In addition to sealing against the resilient sealing material this arrangement further provides an overlapping seal across the connection between the lower fan housing 1836 and the outlet port component 1844. A belt tensioner 1850 is secured to the connecting beams 404 and 406 in proximity with the drive pulley 1802.
The construction of one preferred embodiment the belt tensioner is particularly illustrated in
On a machine without a subassembly capable of moving out of the interior of the cabinet carrying the drive system, these tensioner pulleys may be supported on a frame of any particular shape or design, supported from the cabinet base or walls or any drum supporting framework, and provided with a biasing agent to urge the pulleys toward the drum. For example the support may be by way of a spring loaded telescoping strut.
In the preferred construction of the drive belt tensioner the belt tensioner pulleys 1860 and 1862 are supported by a yoke component 1864 on shafts 1866 and 1868 respectively. The shafts 1866 and 1868 are located in receiving notches 1870 of the yoke 1864. The receiving notches 1870 include a tapering entry portion and part circular receiving portion. The shaft 1866 and 1868 pass a neck between the entry portion and receiving portion during assembly, to locate in the receiving portion and be captured there by the neck. Heads 1872 of the shafts 1866 and 1868 are captured by hooked protrusions 1874 located on the yoke 1864 adjacent each receiving notch 1870. The hooked protrusions 1874 prevent removal of shafts 1866 and 1868 from the yoke 1864 in an axial direction. Preferably the shaft heads are non-circular and cooperate with the protrusions 184 to prevent rotation relative to the yoke 164 which might otherwise induce wear in the receiving notches 1870 eventually leading to release of the shafts.
The yoke 1864 is supported from a belt tensioner bracket 1880 to be reciprocable relative to the diameter of the drive pulley 1802 and rotatable about the drive pulley 1802. A biasing agent is provided between the belt tensioner bracket 1880 and the yoke 1864 to press the yoke 1864 toward the drive pulley 1802. The biasing agent 1882 comprises a carrier 1884 which fits into a cavity 1885 (shown in dot-dash broken lines in
A pivotal slidable connection is provided between the yoke 1864 and the belt tensioner bracket 1880. A centre channel 1894 of yoke 1864 fitting over a central stub 1896 extending off a spanning web 1898 of belt tensioner bracket 1880. Web 1898 spans between the arms of bracket 1880. When assembled and in position the drive pulley 1802 of the drive motor projects into an open cavity 1900 of stub 1896 with the supporting shaft of the motor projecting through a notch 1902 in an end face 1904 of stub 1896. The cavity 1900 is open to its upper side such that in use the belt passing around the drive pulley passes out of the cavity 1900 through the open upper side. When assembled a part annular projection 1906 from stub 1896 locates against a receiving portion 1908 of resilient mount housing 1834. This ensures correct location of the pulley 1802 within the cavity 1900 and relative positioning of the pulley 1802 relative to the belt tensioner assembly.
A wear resistant low friction bush 1910 facilitates the pivotal connection between the yoke 1864 and belt tensioner bracket 1880. In particular the bush 1910 has a rotational interface with the stub 1896 and a slidable interface with the yoke 1864. The bush 1910 preferably includes at least one part frustoconical internal bearing surface 1914 matching an exterior part frustoconical surface 1912 of stub 1896. The bush 1910 further includes a pair of substantially parallel outwardly facing bearing surfaces 1918 which ride against inwardly facing bearing surfaces 1920 of the channel of the channel 1894 of yoke 1864. The bush 1910 includes an extensive notch 1924 in its upper portion to permit the belt to pass from cavity 1900 of stub 1896 when assembled. The bush 1910 includes a thrust flange 1926 which bears against a face of transverse web 1898 of the belt tensioner bracket when assembled. The thrust flange prevents the part frustoconical bearing surfaces of the stub 1896 and bush 1910 from binding in use.
Referring now to
The spring 1886 continues to press the yoke 1864 toward the pulley 1802. Accordingly if the belt lengthens through age or wear the yoke 1864 is pressed forward to increase the length of the bight 1398 of the belt which passes around the pulley 1802, as is depicted in
As has already been discussed the yoke 1864 is rotatable about the drive pulley 1802 as well as being slidable toward and away from the pulley. Rotation about the pulley 1802 is preferable to account for the differing belt tensions between the belt portions 1934 and 1936 with the pulley 1802 operating in differing rotational directions. In the
Accordingly the preferred belt tensioner
In the belt tensioner assembly most components may be formed from plastic materials. However some parts may be usefully formed from other materials. For example shafts 1866 and 1868 may be formed from steel and sliding shoe 1890 may be formed from a sheet metal pressing, for example from brass. Spring 1886 is preferably of conventional form and material for coil compression spring. It will be appreciated that other forms of spring, such as leaf spring or air spring may also be applicable. Given its function the bush 1910 preferably includes a friction reducing filler, for example a plastic composition including PTFE. The sliding carrier 1884 may also be advantageously provided with a similar low friction filler. In the motor support assembly, the motor support bracket 1812, lower fan housing 1836 and resilient support housings 1834 may all be moulded from suitable plastic material.
In the alternative embodiment of
Each pulley 2910 rotates on a bearing 2912 on a shaft 2914 supported by the yoke 2900. Heat dissipating flanges 2920 are connected with each shaft.
The heat dissipating flanges 2920 comprise a hub shield fitted on the shaft and substantially enclosing the hub region of either side of the pulley but not contacting the pulley. The hub shields, like the shaft, do not rotate and are screwed in place by lugs 2930, which clip over edges 2932 of the yoke. The shields are formed of material of high heat conductivity, preferably pressed sheet aluminium.
Drum Hatch 108
With particular reference to FIGS. 1 to 3 the drum (excluding the hatch) broadly is made up of a pair of circular drum ends 105 and 110 and part-cylindrical drum skin 107. The drum ends 105 and 110 are connected with the part-cylindrical drum skin 107 through a folded rim 150 formed along either circumferential periphery.
The drum further includes vanes 186 and 196 connected with the edges 160 and 151 respectively of the part-cylindrical drum skin defining edges of the drum opening. The vanes provide additional rigidity to the drum structure, supporting the drum skin (and in particular the free edges thereof). In addition the vanes are sculpted to assist with even distribution of the laundry load during operation.
The drum end 105 has a double skin in its hub region adjacent the air flow exit and lint collector. The internal face of the air exit and lint collector is displaced somewhat into the interior cylindrical chamber of the drum and is surrounded by inwardly dished facia 165. The outer layer 166 of the drum end includes an annular circle of dimples 153, with a non dimpled region 154 at known angular position relative to the drum opening. The region with an absence of dimples is used to detect the drum rotational position in operation. For locating purposes during manufacture, each vane includes an end protrusion 156 protruding through an aperture 157 in each drum end 105, 110.
The drum hatch 108 includes a part cylindrical section 181 of stainless steel with opposed side edges 185, a leading edge 182 and a trailing edge 183. The side edges 185 are folded outward over on themselves to provide a reinforced edge and present a rolled edge to the channels. An S-bend 184 is formed in the trailing edge 183 of the drum hatch 108. The S-bend is formed to present both an inward hump and an outward hump at the trailing edge of the drum hatch 108 across the width of the drum hatch. The internal hump rides over the external surface of the part-cylindrical drum skin 107 and presents a low friction bearing surface to the drum skin. The external hump ensures that the cut edge of the hatch skin 181 is presented toward the drum rather than away from the drum, improving safety during any maintenance or corrective work on the machine.
The leading edge 182 of the drum hatch 108 is provided with parts of a mechanism for enabling the securement of the drum hatch position relative to the dryer cabinet. In particular the drum hatch is provided with a pair of T-shaped pivoting arms 200. The T-shaped pivoting arms 200 include transverse catch members 201 and a pivot arm 202 connecting between the transverse catch members 201 and the part-cylindrical drum hatch skin 181. The catch members 201 include an axial bore extending from their inner end toward their outer end. A joining rod 203 has its ends fitted within the axial bores 204 of the catch members 201. The rod 203 provides a strengthening backbone for the catch members 201 and reduces the degrees of freedom of their movement. The pivot arms 200 are connected with the drum hatch 108 at their ends away from the catch members 201. The pivot arms 202 are secured to a central double leg 233 of a flat spring member 230. The double arm 233 resides within a recess 213 in the outer face of the pivot arm 202 and is held in place around a centrally located upstand 210 at the head of the recess 213. The double leg 233 is connected to a pair of outer side legs 231 of the spring member 230 via a pair of laterally extending torten portions 232. The outer legs 231 of spring member 230 are clamped between the inner face 235 of a hatch edge stiffening plate 220 and the outer surface of the part-cylindrical drum hatch skin 181. The clamped portions of the spring member 230 may be located within grooves or channels formed in the inner face of the stiffening plate 220.
A stiffening plate 220 is preferably secured to the drum hatch 108. A leading lip 240 of the stiffening member 220 includes slots or recesses in a back edge thereof and is fitted over forward extending tongues 241 of the front edge 182 of drum hatch skin 181. The rear edge of the stiffening member 220 is secured to drum hatch skin 181 by fasteners passing into securing holes 224 of the stiffening member 220. The securing holes 224 preferably correspond with the apexes of the U-shaped sections formed by (sequentially) each connected outer leg 231, torten portion 232 and double leg 233 of spring member 230. This provides additional securement of the spring member 230 in its place between the stiffening member 220 and the drum hatch skin 181.
According to an alternative embodiment of stiffening plate illustrated in
Referring again to
The pivot arm 202 resides within a recess or aperture 221 of the stiffening member 220. The aperture 221 is preferably shaped to match the shape of pivot arm 202 to provide a snug location with the pivot arm 202 in a first position against the drum hatch skin 181.
The aperture 221 includes a forwardly facing butting face 225 adjacent the recessed neck 236 and securing holes 224. The butting face 225 butts against a corresponding butting face 211 at the end of pivot arm 202 distil from the catch member 201.
The aperture 221 also includes rear facing butting surfaces 222 which butt against forward facing butting surfaces 212 of pivot arm 202 with the pivot arm 202 in its first position. Therefore, at least in its first position, the pivot arm 202 is prevented from significant forward movement relative to the stiffening member 220 by butting of the faces 222 and 212.
The pivot arms 202 are pivotable about their ends distal from the catch 201 to a second condition away from the drum hatch skin 181. In both the first and second position the T-shaped pivot member 200 is restrained from rearward movement relative to the stiffening member 220 by butting of the pivot member butting surface 211 and the stiffening member butting surface 225.
Clearly an alternative but less preferred connection between the catch members 201 and the drum hatch 181 could include simple hinges fastened to the drum hatch skin with any appropriate spring mechanism operating between the drum hatch skin and the catch member.
However the presently described mechanism is preferred due its simplicity of assembly which is now described. The stiffening member 220 is fitted to the drum hatch skin 181 by fitting the recesses of lip 240 over tongues 241 and inserting fastenings through holes 250 of drum hatch skin 181 to secure through corresponding holes 224 of the stiffening member 220. The T-shaped pivot arms 200 are pre-assembled with the connecting rod 203. This pivoting assembly may then be secured to the stiffening member 220 by passing the outer legs 231 of the spring members 230 below the under side of the stiffening member 220 from the rearward edge thereof with the u-shaped section 233 pushed into the pivot arm recess 213.
According to an alternative and preferred embodiment illustrated in FIGS. 31 to 33 the drum hatch stiffening member includes a labyrinth formation along its opening edge and the opposed edge of the drum opening includes a complementary labyrinth form, such that, for the drum hatch to fully close the labyrinth forms must engage into one another with close tolerance.
The labyrinthine formation of the stiffening member (
The walls must fully engage in the sockets, as in
As illustrated in
Also as illustrated in
Drum Hatch Engaging Mechanism
The clothes dryer is provided with a drum hatch engaging mechanism connected with the cabinet. The mechanism secures the drum hatch against movement relative to the housing at the beginning of a drum opening operation and throughout the period when the drum is open or partially open, and releases the drum hatch at the conclusion of a drum closing operation. In performing this function the drum hatch engaging mechanism operates to engage, hold and subsequently release the catch members 201 of T-shaped pivot arms 200.
Referring particularly to FIGS. 3 to 3B, 6 to 10 and to
In the preferred form of the invention the drum engaging member comprises a pivoting door or flap 300. The pivoting flap 300 includes a pivot bar 301 along a rear edge which extends laterally as a pair of cylindrical stubs 302 to engage within sockets of side housings 304 and 305. A channel member 361 spans between the housings 304 and 305 and is connected to the housings at its ends. The channel member 361 maintains accurate separation of the housings 304 and 305 and location of rotation bar 301 therebetween. The pivot bar 301 resides within an open channel 362 of the channel member 361. The channel 362 supports the pivot rod 301 along its length, reducing the stresses on stubs 302.
The flap 300 includes a leading face 315 spanning the width of the drum opening. The face 315 provides a barrier to entry into the space between the drum and the housing when the flap 300 is in its engaging position.
The ramped abutments 311 are provided projecting from an inside face backing on to leading face 315 and projecting toward the pivot bar 301. The ramped abutments take the form of teeth, tapering to a point spaced from the engaging member 300. Each tooth has an internal edge 3302 for receiving the catch member 201 and an external edge 3304 for sliding on the surface on the drum skin.
The flap 300 has a main connecting face 313 connecting between the internal face and the pivot bar 301 across the width of the flap. The closing abutments 310 project from the face 313 and have abutment edges 314 facing the ramped abutments 311. The projection of closing abutments 310 from the face 313 is significantly less than the projection of ramped abutments 311 from the face 313. In an opening operation the projections 310 will clear the catch member 201 while the points of ramped abutments 311 hook under the catch members 201.
The tracks 109 of drum 104 terminate at their forward ends 320 to provide end faces against which the outward ends of catch members 201 butt with the drum hatch 108 closed.
The T-shaped pivot arms 200 are raised to a drum opening position by riding up the ramped abutments 311 of drum engaging flap 300. During drum opening the catch members 201 are raised clear of the end faces of track ends 320. After initiation of opening rotation of the drum with the drum hatch held in place by the flap 300 the outer ends of catch members 201 reside above the outer surface of tracks 109. In this condition they are held between the outer surface of tracks 109 and the face 313 of flap 300. In a circumferential direction of the drum they are blocked from movement in one direction by the ramped abutments 311 and in the other direction by the closing abutments 310. During the opening rotation of the drum the catch members 201 will tend to bear against the ramped abutments 311.
During a closing rotation of the drum, as illustrated in
The flap 300 is moveable between an engaging position and a non-engaging position. The effect of the drum engaging flap 300 in the engaging position has been described above. In the non-engaging position the drum engaging flap 300 is pivoted to have its drum engaging end away from the surface of the drum.
To assist with retention of the drum engaging flap 300 in a position to pick up the catch members 201 during an opening sequence an arrangement is preferably provided for retaining the flap 300 close to the drum from a point shortly in advance of initial abutment with the catch members 201 and then throughout subsequent opening and closing until the catch members 201 are released with the drum lid fully closed. Referring to
Pivoting of the hatch engaging flap 300 can be described with particular reference to
The preferred actuation mechanism includes a worm drive gearbox with a first gear 337 rotatable about a hub 350 and including outwardly extending peripheral teeth 338. A drive gear 333 includes a spiral thread 334 engaged with teeth 338 of the first gear. The drive gear is supported between end support walls 336 and is driven by an electric motor 332.
To absorb vibration a rubber spacer (not shown) may be provided under the motor, lodged and compressed between the motor and the housing. Also to absorb vibration at least one of the ends of the drive gear 333 is supported within a resilient mounting in its respective support wall 336. For example, as illustrated, the far end may be supported within a bearing, such as in a seat or plastic bearing, with the bearing mounted within a rubber mounting board 360 fitted into an aperture in the wall 336.
The first gear 337 and/or the drive gear are formed so that in operation together a positive stop action is provided at either end of a drive envelope comprising less than a full turn of the first gear 337. The positive stop is provided by collision of drive gear structure with first gear structure when the first gear reaches either of its rotation limits. One preferred combination of drive gear and first gear structures is described below which absorbs the collision impact, but other structures are also envisaged to be within the scope of this invention. For example the spiral thread of the drive gear may have a square end at either end of the spiral in the first gear may lack expected teeth valleys at the requisite end stops. The square end of the spiral thread will collide against a respective face of the first gear when it reaches the unexpectedly missing valley.
Only a substantial proportion of the circumference of the first gear 337 includes peripheral teeth 338. Adjacent each end of the toothed portion of first gear 337 is an outwardly placed collision member 339, 340. The collision members 339, 340 have a greater radial extent than the peripheral teeth 338. The collision members 339 and 340 are preferably formed to provide flexibility adjacent the ends of the toothed portion 338 of the first gear 337. For example, collision members 339 and 340 preferably extend from the first gear 337 at a position circumferentially back from the toothed portion 338 of first gear 337 and extending in a circumferential manner, spaced from but parallel the form of first gear 337, to end adjacent the ends of toothed portion 338. Thus the ends of the collision members 339 and 340 may deflect somewhat under transverse pressure by flexing of the collision members.
Rotation of the first gear is stopped in either direction by collision of the respective collision member 339 or 340 with the drive gear. Preferably the drive gear includes protrusions from its shaft at positions displaced from the ends of spiral thread 334 and the collision of collision members 399 and 340 is with the protrusions 335 rather than with the spiral thread 334. Preferably these protrusions are non-annular and extend as a transverse lugs. Movement of the first gear is halted by the cessation of rotation of the drive gear on collision of the lugs 335 with the tips of collision members 339 and 340.
Cessation of rotation of the drive gear while the electric motor 332 is energised leads to a rapid and detectable increase in the motor current. The voltage applied to the motor may be removed upon detection of this increase in motor current although with some motor and power supply combinations this may not be necessary. In the preferred form of the invention the motor current is sensed by a one-bit digitisation circuit, as exceeding or not exceeding a threshold. An electronic controller switches off power supply to the motor as soon as the digitising circuit indicates the motor current has exceeded the threshold level.
Consequently the collision members 339 and 340 define the end limits of movement of the first gear 337. These end limits of movement are depicted in
A disc 341 is located in a circular aperture 351 in the body of first gear 337 opposite collision members 339 and 340. Actuation rod 331 extends through an aperture in a lug extending from disc 341. The lug is slidable along the collecting rod 331 and disc 341 is rotatable within its aperture 351 in the first gear 337.
In rotation of the first gear from the position shown in
In the reverse movement of first gear 337, between the conditions in
General drying operation of the dryer will not be described in detail. Once the dryer is in an operating mode the preferred operating mode involves appropriate cycling of the drum rotation through sequences of rotation in one direction with heat applied to incoming air followed by a briefer period of rotation in another direction without heat applied (or with heat applied at a lesser rate) generally for disentanglement proposes. In particular it is preferred that heat is only applied when the drive motor is driving the fan in its more efficient direction. If separate drive motors are employed to drive the drum and drive the fan then application of heat to the incoming air may be effected entirely independently of the drum rotation direction.
Moisture sensing of items in a drying load by resistance sensing between a pair of conductive contacts is also known in the art and will not be described in detail. Preferably the controller enters the dryer into a cool down mode (where the drum is rotated and air flow applied without heat) when the sensed moisture content is less than or equal to a moisture content corresponding with the user selected level. It will be appreciated that other methods of detecting moisture content (for example air outlet temperature profiles and air outlet moisture levels) may be used, and in all cases user selected moisture levels may correspond with raw or processed sensor levels rather than any absolute moisture content. Lid locks and operation thereof in conjunction with a lid sensing circuit are also well known in the art (particularly of top loading washing machines) and will not be described herein. Needless to say the controller institutes a lock out on operation of the machine in the absence of the sensor indicating the lid to be in a closed condition, and maintains the lid lock in a locked condition throughout operation.
Preferred methods of operation of the dryer through drum opening and drum closing operations, and through an initialisation procedure on power up, form aspects of the present invention and accordingly the preferred embodiment thereof will be described in detail with reference to the Figures.
The opening and closing operations of the dryer and an initialisation procedure each include speed controlled operation of the drum to and/or from known rotational positions and actuation of the drum hatch engaging flap between retracted and extended positions.
Drum position is sensed via the light sensor 910. Referring in particular to FIG. 5 a and 5 b drum end 726 includes an annular array of dimples 950 pressed out of the face thereof. At least the periphery of these dimples scatters light from the adjacent light sensor 910 during rotation of the drum. The dimples 950 are regularly spaced apart, with a single dimple missing from its expected position in the annular array. A position monitoring algorithm increments or decrements (depending on drum rotational direction) a drum position variable with the passing of each dimple. A missing dimple detection loop checks for the long unbroken signal indicating the missing dimple, incrementing or decrementing the position variable to account for the missing dimple and using this detection to reset the position variable when required. Position readings are therefore taken from the position from the missing dimple as datum, which is a known rotational position relative to the other physical features of the drum, such as opening and closing edges of the drum opening.
It is not necessary that the controller monitor drum position throughout normal drying operation, as drum position may be re-established within one full rotation of the drum when necessary for an opening operation.
The drum drive motor is preferably a standard AC induction motor. The drum drive motor speed is controlled for opening and closing operations by chopping the applied AC voltage with a variable duty cycle to vary the effective applied AC voltage. The drum speed may be continuingly sensed via the light sensor. The periodic interruption of the received light at the light sensor by the scattering of light from the drum end dimples is detected. The rate of interruption is directly proportional to the drum speed in a known relationship. The controller determines the relationship between the drum speed and the required drum speed for the opening operation by monitoring this interruption rate and feedback controls the chopping duty cycle to maintain the drum speed at or close to the desired drum opening speed.
Alternatively the drum drive motor may be speed controlled by a variable frequency inverter operating from a rectified power supply.
Where necessary the controller determines that the drum is still rotating by the continued periodic interruption of the light sensor signal. The timer detecting interruption intervals for the missing dimple detection loop also indicates a ceasing of drum rotation as soon as the elapsed time since the last signal interruption exceeds a predetermined threshold. The threshold may be a predetermined time period or derived from previous interruption intervals.
For drum engaging flap actuation, operation of the actuator motor has already been described, including detection of end points by current sensing of the actuator motor drive currents. In addition, during actuation of the actuator drive motor the controller tracks the elapsed time between initiating energisation of the actuator motor and the motor becoming stalled. The controller routinely checks this elapsed time against an expected range. An elapsed time outside the expected range indicates the possibility of incomplete activation of the hatch engaging flap.
Operation of Dryer Through a Drum Opening Operation
The drum opening operation will be described with particular reference to
A drum opening operation is generally performed at the termination of a drying cycle. At the beginning of the drum opening operation the drum is generally rotating at operating speed. At step 1001, the controller determines whether the drum is rotating in the door opening system. If the drum is rotating forwards (anti-clockwise in
At step 1002 the controller reduces the drum drive motor speed. Rotational speed is determined at step 1003, and further reduced at step 1002 until the speed of the drum reaches a safe drum opening speed. The controller then continues rotation at reduced speed until the loop of steps 1004 and 1005 determines that the drum has reached a rotational position that is a safe drum position for extending the drum hatch engaging flap. Preferably this position is set so the hatch engaging member will reach full extension with the drum so that the drum is not required to rotate through more than a short distance at low speed before the drum hatch is engaged.
At step 1006 the controller energises the actuator motor 323 to rotate the drum hatch engaging flap into its engaging position with the external edge of the ramped abutment teeth sliding on the surface of the drum skin. At step 1007 the controller detects the moment when the first gear arm 339 collides with the drive gear lug 335, by the increase in current in actuator motor 323. The controller times the interval between beginning energisation at step 1006 and stalling of the actuator motor and determines at step 1007 whether the interval is within an expected range. If the interval is within the expected range the controller de energises the hatch engaging member motor at step 1009 and continues on its procedure. If the interval is outside an expected range this indicates possibility of a fault and at step 1008 the controller either ceases machine operation and indicates an alert or enters a recovery routine.
This extended position of the drum engaging flap is depicted in
Referring again to
The controller continues to monitor the rate of interruptions of the light sensor signal to determine at step 1012 the instant when the drum ceases rotation. The controller may also be configured with a current sensing circuit to monitor the motor current to determine cessation of motor rotation by a rapid increase in motor current.
Rotation of the drum is eventually halted by an abutment on the underside of the hatch engaging flap 300 coming to rest against a halting abutment protruding from the outer surface of the side channel 109.
As soon as the controller detects halting of rotation of the drum at step 1012 it de-energises the drum drive motor. At step 1013 the controller determines whether the drum has reached a door fully open position from its current drum position calculation. If it is the controller stops operation of the machine and disengages the lid lock at step 1015. If the controller determines that the drum has not reached a door open position then at step 1014 the controller stops operation of the machine and indicates an alert or enters a recovery mode.
The controller may apply a mechanical or electrical brake to maintain the drum in its open position. The brake may for example comprise connecting a substantial electrical resistance across the windings of the drum drive motor.
Operation of Dryer Through a Drum Closing Operation
The drum closing operation is largely the reverse of the drum opening operation. It will be described with reference to
Prior to closing the drum in a drum closing operation the controller energises the lid lock solenoid at step 1020 and confirms at step 1022 that the lid lock has successfully activated. If the lid lock has not successfully activated then the lid lock solenoid is de-energised at step 1024 and a user alert is activated.
Once the lid lock has been successfully activated the closing operation proceeds to a drum slow closing loop comprising steps 1026, 1028 and 1030.
At step 1026 the controller energises the drum drive motor to rotate the drum in the drum closing direction at a drum closing speed.
The controller continues to energise the drum drive motor to rotate the drum at the drum closing speed until the drum is past a door closed position, detected at step 1030.
Between steps 1026 and 1030 in each loop the controller, determines that the drum is still rotating at step 1028. If it detects the drum has stalled then the controller executes an error catching operation, beginning with halting rotation of the drum by de-energising the drum motor at step 1032. The controller then executes a drum opening loop comprising steps 1034 and 1036. At step 1034 the controller energises the drive motor to rotate the drum in a door opening direction at a door opening speed, detecting completion of the opening operation at step 1036 by non rotation of the drum. Once the remedial drum opening operation is completed operation of the machine is stopped at step 1038 and a user alert is activated. Alternatively the controller may be configured to return to step 1026 and retry the closing operation.
Once it determines that it has reached the closed position at step 1030 the controller energises the actuator motor 323 at step 1040, in a reverse direction to withdraw the drum engaging flap to its disengaged position. At step 1042 the controller detects stalling of the actuator motor and compares the elapsed motor actuation time with an expected range. If the elapsed time is outside the expected range the controller ceases machine operation at step 1046 and activates a user alert. Alternatively the controller may be configured to initiate a recovery operation. If the elapsed time is within the expected range then at step 1044 the controller de energises motor 323 at step 1044. The controller then begins operation in a drying cycle at step 1048, including accelerating the drum to normal operating speed by ceasing chopping of the driving voltage of the drum drive motor.
Therefore in the drum closing operation the drum starts from rest and is rotated in a forward direction (anti-clockwise in
If, as in
Generally the controller is active even when the drying appliance is not operating. In its soft powered down mode the controller continues to retain in memory a record of the current drum position and hatch engaging flap position. However these position records are lost if the appliance is hard powered down, for example due to a power supply failure or being switched off at the wall or being unplugged, including on initial installation.
To establish correct status values for the appliance after a hard reset the controller progresses through an initialisation procedure. The initialisation procedure is illustrated in
The initialisation procedure begins with a drum closing operation substantially in accordance with steps 1020 to 1038 of
In particular at step 1050 the controller energises the lid lock solenoid, and checks correct activation of the lid lock at step 1052, stopping operation and activating a user alert at step 1054 if the lid lock has not engaged. If the lid lock has properly engaged then the controller begins a drum closing loop of steps 1056, 1058 and 1060. Step 1060 differs from step 1030 of the normal closing operation in that it detects only that the drum has rotated a sufficient rotational angle to have fully closed the door if the door had been fully open. If the controller detects at step 1058 that the drum has stalled, before determining at step 1060 that the drum has rotated a sufficient angle to have closed the door, then it halts rotation of the drum at step 1062 and initiates a drum opening loop of steps 1064 and 1066. It initiates rotation of the drum in a door opening direction in step 1064 until determining the drum as stalled at step 1066 at which time it stops machine operation and activates a user alert at step 1068.
If the controller determines at step 1060 that the drum has rotated sufficient distance to have closed the door then at step 1070 the controller de energises the drum drive motor at step 1070. The assumption is made that the drum is now in a closed condition irrespective of its starting condition.
At step 1072 the controller energises the hatch engaging flap actuator motor in a rotational direction to retract the hatch engaging flap. At step 1074 the controller determines if the actuator drive motor stalls within a short period, essentially instantly, and if so proceeds to a sub routine of steps 1076 to 1088.
If the motor did not stall instantly then at step 1090 the controller determines whether the actuator motor stalls within a present maximum time. If not then at step 1092 the controller stops operation of the machine and activates a user alert. If the actuator motor has stalled within a maximum time then at step 1094 the controller stops energisation of the actuator motor and re-energises the actuator motor in a direction to advance the drum hatch engaging flap. At step 1096 the controller determines whether actuator motor stalls within an expected elapsed time range, if not proceeding to step 1098, stopping machine operation activating a user alert. If the controller determines at step 1096 that the hatch engaging member motor has stalled with the elapsed time within the expected range then at step 1100 the controller stops energisation of the actuator motor, and re energises the actuator motor in a direction to retract the drum hatch engaging flap, detecting at step 1102 whether the actuator motor stalls with an elapsed time within the expected range. If the controller detects at step 1102 that the elapsed time is outside the expected range then at step 1104 the controller stops operation of the machine and activates a user alert. Otherwise at step 1106 the controller commences an opening operation in accordance with
If at step 1074 the controller determines that upon initial energisation the actuator motor stalled instantly, then at step 1076 the controller stops energisation of the actuator motor and re-energises the actuator motor in a direction to advance the drum hatch engaging flap. The controller determines at step 1078 whether the elapsed time between energising the actuator motor at step 1076 and the motor stalling falls within an expected range. If not, the controller stops operation of the machine at step 1080 and actuates an user alert. If at step 1078 the elapsed time was within the expected range then at step 1082 the controller stops energisation of the actuator motor and re-energises the actuator motor in a direction to retract the drum hatch engaging flap. At step 1084 the controller determines whether the elapsed time between energising the actuator motor at step 1082 and the motor stalling is within an expected range. If not then at step 1086 the controller stops operation of the machine and activates a user alert. Otherwise at step 1088 the controller de energises the actuator motor, and commences a drying procedure including energising the drum drive motor at a normal operating speed.
Automatically commencing a drying operation if the initialisation process indicated a closed drum position with hatch engaging member retracted may be a user option set in non volatile memory. It is a useful option which ensures that operations interrupted by power cut are completed without user intervention.