US3890719A

US3890719A - Broken belt power-disconnect system for dryers

Info

Publication number: US3890719A
Application number: US436448A
Authority: US
Inventors: Albert T Braga; Robert A Brenner; Jr Ralph S Odle
Original assignee: Whirlpool Corp
Current assignee: Whirlpool Corp
Priority date: 1974-01-25
Filing date: 1974-01-25
Publication date: 1975-06-24
Anticipated expiration: 1992-06-24

Abstract

A clothes dryer employs a pivotally mounted resilient idler for tensioning a drive belt which is entrained about a pulley of the dryer drive motor and a rotatable dryer drum, the idler pivoting to a free position upon release of belt tension due to belt breakage or the like. A separable connector is serially connected in at least one power lead of the drive motor and associated with the idler to be separated and thereby to break the power circuit of the motor as the idler moves towards its free position.

Description

Unite Sttes Patent Braga et al.

BROKEN BELT POWER-DISCONNECT SYSTEM FOR DRYERS Inventors: Albert T. Braga, Stevensville;

Robert A. Brenner, St. Joseph; Ralph S. Odle, Jr., Michigan City, all of Ind.

Whirlpool Corporation, Benton Harbor, Mich.

Filed: Jan. 25, 1974 Appl. No: 436,448

Assignee:

US. Cl. 34/55; 34/43; 74/2l6.5 Int. Cl. F26b 19/00 Field of Search 34/44, 43, 45, 46, 55;

References Cited UNITED STATES PATENTS 12/1951 Butler 34/55 June 24, 1975 2,641,062 6/1953 Wentz 34/44 2,803,454 8/1957 Tatro 74/2165 Primary Examiner-John J Camby Attorney, Agent, or FirmHill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson A clothes dryer employs a pivotally mounted resilient idler for tensioning a drive belt which is entrained about a pulley of the dryer drive motor and a rotatable dryer drum, the idler pivoting to a free position upon release of belt tension due to belt breakage or the like. A separable connector is serially connected in at least one power lead of the drive motor and associated with the idler to be separated and thereby to break the power circuit of the motor as the idler moves towards its free position.

A STRACT 11 Claims, 5 Drawing Figures BACKGROUND oF THE INVENTION 1. Field of the Invention This invention relates to automatic clothes drying machines, and more particularly to a power disconnect system for automatically terminating operation of a clothes dryer in response to breakage of the dryer drum drive belt.

2. Description of the Prior Art Various apparatus is known in the prior art for sensing the condition of a drive belt. For example, U.S. Pat. No. 3,308,795 discloses an engine cut off device for an automobile in which contacts are closed by a pulley, upon release of tension on its mount, to short circuit the engine ignition system. U.S. Pat. No. 1,213,968 discloses a web moisture sensing arrangement for a paper making machine for controlling the amount of moisture in the traveling web. U.S. Pat. No. 1,882,275 discloses an engine cut off mechanism for an internal combustion engine in which a switch is employed to open the energizing circuit thereof in response to breakage or displacement of the fan belt. Further, U.S. Pat. No. 2,679,112 discloses a pivotally mounted idler mechanism for adjusting the tension on a belt drive for a clothes dryer drum.

SUMMARY OF THE INVENTION The primary object of the present invention is' to provide a safety feature for a clothes drying machine which will effect automatic shut off of the machine if the belt driving the dryer drum should break or otherwise become inoperatively displaced with respect to the dryer drum or the drive motor. A more specific object of the invention is to provide a power disconnect system for a clothesdryer which will remove power from the dryer drive motor in response to belt breakage or the like.

Another object of the invention is to provide a power disconnect system for a clothes dryer which will terminate the operation of the dryer, especially the heater means for supplying hot or warm' air to the dryer drum, in order to protect fabrics within the drum and to prevent any damage to the dryer or its surroundings caused by overheating.

According to the invention, a resilient idler bracket carrying an idler pulley is pivotally mounted on the base of a clothes dryer. A flexible drive means in the form of a drive belt which constitutes a tensioned transmission member between the drive motor and the dryer drum biases the resilient idler bracket to a first position, its normal operating position. If the transmission member or drive belt should break, or otherwise become inoperatively associated with the dryer drum or drive pulley of the drive motor, the resilient idler bracket will pivot toward a second position wherein it is in a free attitude.

In one embodiment of the invention a power lead from the electrical supply to the .drive motor includes a separable connector having first and second parts, the first part being fixedly. mounted on the drive motor mounting bracket and thesecond partincluding an arm portion which extends into the path oftravel of the idler bracket. Therefore, upon movement 'of the idler bracket toward its free second position or free attitude, the idler bracket strikes the extending arm of the second connector part to effect separation of the two parts of the separable connector and thereby disconnection of the drive motor from the electrical supply.

In another embodiment of the invention, the power lead to the drive motor is secured at a first point thereof to the base of the laundry machine and at a second point thereof to the idler bracket. A separable connector is provided in the power lead between the first and second points so that movement of the idler bracket toward its free attitude or second position causes one connector part to be yanked out of engagement with the other connector part to effect an opening of the power circuit for the drive motor.

In both embodiments, the heater circuit of the clothes dryer is connected to the electrical supply by way of a drive-motor-operated centrifugal switch which is only closed when the drive motor rotates above a predetermined speed. Therefore, a deenergization of the drive motor and consequent slowing of the motor to a speed below the predetermined speed effects deenergization of the heater circuit, and thus the heater means, and prevents damage to fabrics or other hazards which could be occasioned by excessive heat.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the invention, its organization, construction and operation will be best understood from the following detail description of certain embodiments of the invention taken in conjunction with the accompanying drawings, on which:

FIG. 1 is a cut away sectional view of an automatic clothes dryer constructed in accordance with the principles of the present invention;

FIG. 2 is a side elevational view of a terminal block type disconnect system constructed in accordance wit the invention; I

FIG. 3 is another view of the apparatus illustrated in FIG. 2, as viewed in the direction IIIIII of FIG. 2;

FIG. 4 is a side elevational view of another embodiment of a power disconnect system according to the present invention; and

FIG. 5 is a schematic circuit diagram of a typical dryer control circuit with which the present invention may be utilized to great advantage.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a laundry machine or clothes drying appliance 10 is illustrated as comprising an enclosure cabinet or housing 12 with a control console 14 thereon, housing a control device 16 for regulating the drying operation. A control knob 18 selectively sets the control device 16 for various drying cycles of operation, as for example, automatic or timed drying cycles. The enclosure cabinet or housing 12 comprises a horizontal top panel 20 and a horizontal bottom panel or base 22, a pair of vertical side panels 24, a vertical front panel 26 and a vertical rear panel 28. An access opening 30 is provided in the front panel 26, as defined by an axially in-turned flange 31, having a closure door 32 cooperating therewith for loading and unloading the clothes drying appliance or dryer 10.

The dryer 10 further includes a fabric treatment zone or drying container for tumbling clothes, in the form of a rotatable drum '34 housed within the cabinet 12 and extending axially from the front panel 26 to a bulkhead '36 spaced forwardly of the rear panel 28. In order to encourage tumbling action in the clothing being dried, a plurality of circumferentially spaced baffles 78 (only one being illustrated) are mounted on the inner surface of the drum 34. The drum 34 includes a radially inwardly extending front closure wall 41 having an access opening 42 therein formed by means of an axially outturned flange 43. The flange 43 provides a forwardly extending bearing annulus which overlies and is suitably journalled on the complemental flange 31 of the cabinet 12. It will be apparent from the foregoing that the opening 42 into the drum 34 and the opening 30 formed in the front panel 26 are substantially concentric, providing access into the rotatable drum 34 from outside the cabinet 12. The drum 34 is supported at the rear by a pair of support rollers 48 (only one being illustrated) mounted on the bulkhead 36. A raceway or circumferential groove 50 indented in the peripheral wall of the rear portion of the drum 34 serves as a track for the rollers 48.

A drive motor 52 is mounted on the bottom panel or base 22 in a rear corner of the cabinet 12 and rotatably drives the drum 34 by means of a transmission, in this instance a tensioned transmission member or endless drive belt 54, which extends around the periphery of and in frictional engagement with the drum 34 and around a motor pulley 56 mounted at one end of a motor shaft 58. An idler device 91 has an idler pulley 94 rotatably mounted on a resilient idler bracket 92 which, in turn, is pivotally mounted about point P on the bottom panel 22 so as to be biased against the tension of the drive belt 54. As shown in FIGS. 24, a power lead 104 supplies or delivers power to the motor 52 and includes a separable connector (82 in FIGS. 2 and 3 and 108 in FIG. 4) for disconnecting the drive motor 52 from the electrical supply in response to an inoperative belt condition, as will be more specifically set forth below. The other end of the motor shaft 58 drives a blower 60, arranged to circulate air through the drum 34. The blower 60 is included in a warm air system 62 positioned between the rear panel 28 and the bulkhead 36.

The bulkhead 36 serves to enclose the openended rear portion of the drum 34 and provides a fixed rear wall in which to locate a pair of spaced openings comprising an air inlet 64 and an air outlet 66. The blower draws moisture-laiden air from the interior of the drum 34 through the outlet 66, through a removable lint screen 68, an air duct 70, through the blower 60 and out of the cabinet 12 through an exhaust duct 72. Air exhausted from the drum 34 is replaced by ambient air entering the warm air system 62 by way of an air intake opening (not shown) in the rear panel 28, the ambient air being drawn through a fresh air duct 74, passing over a heater means 76 and into the drum 34 through the inlet 64. The warm air system 62 thus circulates a stream of warm air through the drum 34, subjecting clothing placed therein to a drying environment to remove moisture from the fabrics while the clothing is tumbled as the drum rotates.

Referring now to FIGS. 2 and 3, one embodiment of a power-disconnect system is illustrated wherein a separate connector 82, in this instance a terminal block, is fixedly attached to a motor bracket 84 by a pair of screws 86. A removable portion 88 of the separable connector 82, having a laterally extending arm portion 96, is located by a pair of pins 90, and is disconnected from the fixed portion 88a of the terminal block 82 when the extended arm portion 96 is struck by the idler bracket 92. The idler bracket 92 is constructed of spring steel, or a like material, and, as shown, in its extended position is biased against the tension of the drive belt 54. The drive belt 54 rides on the idler pulley 94 which is, in turn, rotatably mounted on the idler bracket 92 by a bearing 98. Should the drive belt 54 break, for example, the idler bracket 92 is released to its free position or attitude (illustrated by broken lines). In the course of travel from its extended to its free position or attitude, the idler bracket 92 strikes the extended arm portion 96 of the removable portion 88 of the terminal block 82, thereby breaking the connection between the fixed and movable parts 880 and 88, respectively, of the terminal block to interrupt power to the motor being supplied by way of the power lead 104. The circuitry of the clothes dryer appliance 10 is such that when the motor 52 is inoperative no power is delivered to any component which could affect fabric treatment. Therefore, the breaking of the drive belt 54 has the effect of shutting down the clothes drying appliance 10.

Referring now to FIG. 4, another embodiment of the invention is illustrated for a power-disconnect system wherein the power lead 104 is firmly attached at one point to the idler bracket 92 by means of a clamp 106. A separable connector 108 forms a part of the power lead 104 and is rigidly located on the motor base plate 110 by a screw 112 so that both separable parts of the connector are between the point of connection of the power lead to the idler bracket and the point of connection of the power lead to the base plate. In this embodiment, if the drive belt 54 should break, the power lead 104 is opened at the connector 108 by the force of the idler bracket 92 traveling toward its free position (the free position being again shown by broken lines).

FIG. 4 further illustrates the provision of a relatively simple pivot for the idler bracket 92 which comprises a slot 114 in the base plate 110 for receiving an S- shaped portion 116 of the idler bracket 92. Upon release, the bracket 92 is therefore free to pivot without the necessity of providing a pin or the like for the pivot access.

Turning now to FIG. 5, an exemplary electrical circuit for controlling the operation of the dryer 10 is illustrated as comprising a drive motor 52, and a programmer or control device 16 including a timer motor 122 coupled to the control knob 18. The control device 16 further includes a plurality of timer-controlled,

camoperated contacts

124, 126, 128, 130, 132 and 134. The electrical circuit also includes a heater circuit, and a door-controlled

switch having contacts

142 and 144. The drive motor 52 and the timer motor 122 are connectable to a power source, normally a conventional electrical supply, by way of the terminals L1 and N, while the heater circuit is connectable to the electrical supply by way of the terminals L1 and L2. The heater circuit includes a pair of thermostats 1'36 and 138, heater means 76 shown as having

heater elements

146 and 148, and a motor-controlled centrifugal switch 150 for interrupting power to the heater means when the motor speed drops below a predetermined,

value. A detailed description of the operation of this form of dryer circuit is specifically set forth in US. Pat. No. 3,571,941, issued to Richard L. Garfield and Harold S. Stacik and assigned to Whirlpool Corporation. Therefore, a detailed description of the operation 5 of the'circuit will not-'be given here. It should here be noted,-however, that 'tlieswitch -150 is only closed to supply power to the heater means 76 when'the drive motor 52has a rotational speed above a predetermined value. When the motor-s rotational speed falls below the predetermined value, at termination of a drying operation, or in response todeenei'gization of the motor in accordance with the presenti'nvention, the heater means is deenergized to prevent overheating of the fabrics being dried, the machine itself, or the area in proximity to the machine.

Although the circuit could be broken at other points, or at multiple points of the circuit, an X in FIG. 5 denotes one such point in the power circuit for delivering electrical power from a power source to the drive motor which may be controlled by the terminal block 82 or by the connector 108. It is readily apparent that if this power lead L is opened, power delivery via lead L will be interrupted, and the drive motor 52 will become deenergized and the operation of the motor and heater will terminate.

Although we have described our invention by reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. We, therefore, intend to include within the patent warranted hereon all such changes and modifications as may reasonably and properly be included within the scope of our contribution to the art.

What is claimed is: l. A clothes drying machine comprising: a rotatable drum; a drive motor; a power lead for delivering power from a power source and electrically connected to said drive motor; flexible drive means coupling said drive motor and said drum for rotating said drum when said drive motor is energized via said power lead; and power-disconnect apparatus including a separable connector in said power lead, idler means in mechanical contact with and tensioning said flexible drive means, and

separating means mechanically interacting together with said idler means for separating said connector in response to loss of tension from said flexible drive means.

2. A clothes drying machine comprising:

a base;

a housing and a drive motor mounted on said base, a power lead for delivering power from a power source and electrically connected to the motor;

a drum rotatably mounted within said housing;

flexible drive means driven by said drive motor and coupled to said drum for rotating said drum; and

a power-disconnect system including an idler means mounted on said base and having a first position tensioning said flexible drive means.v

and a second position wherein said idler means is in a free attitude, and

means responsive to the tension of the flexible drive means for moving the idler means from its first to its second position,

a separable connector, located in said power lead at some point along its length, said power lead being rigidly attached to said base at a first point on one side of said separable connector and to said idler means at a second point on the other side of said separable connector, said connector being separated in response to movement of said idler means from said first position toward said second position.

3. A clothes drying machine according to claim 2, wherein said means for moving the idler means includes a resilient member urged by said flexible drive means toward said first position.

4. A clothes drying machine according to claim 2, wherein said idler means includes a resilient idler bracket pivotally mounted on said base and connected to said second point of the power lead.

5. A clothes drying machine according to claim 2, wherein said flexible drive means includes an endless drive belt.

6. A clothes drying machine according to claim 2, having heater means for affecting the temperature in the drum and controlled by a heater circuit connected to the power source, said heater circuit including a centrifugal switch for controlling power to said heater means in response to operation of said drive motor, said centrifugal switch operating to terminate power to said heater means in response to a rotational speed of said drive motor below a predetermined level.

7. A clothes drying machine according to claim 6, wherein said flexible drive means includes an endless drive belt, and said idler means includes a resilient idler bracket pivotally mounted on said base and held in said first position biased toward said second position by said belt, said second point of connection of said power lead being near the distal end of said bracket with respect to its pivot on said base.

8. A clothes drying machine comprising:

a base;

a housing and a drive motor mounted on said base;

a power lead for receiving power from a power source and electrically connected to the motor;

a drum rotatably mounted within saidhousing;

a power-disconnect system including an idler means mounted on said base and having a first position tensioning said flexible drive means and a second position wherein said idler means is in a free attitude, means responsive to the tension of the flexible drive means for moving the idler device from its first to its second position, and

a separable connector, located in said power lead at some point along its length,

said separable connector including first and second parts,

said first part being fixedly mounted in proximity to said idler means and said second part including means for contacting said idler means as said idler means moves toward its second position, whereby said parts are separated by said contact from said idler means whenever tension is removed from said flexible drive means.

9. A clothes drying machine according to claim 8, wherein said flexible drive means includes an endless drive belt, and said idler means includes a resilient idler bracket pivotally mounted on said base and held in said first position biased toward said second position by said belt.

having heater means for affecting the temperature in the drum and controlled by a heater circuit connected to the power source, said heater circuit including a centrifugal switch for controlling power to said heater means in response to operation of said drive motor, said centrifugal switch operating to terminate power to said heater means in response to sensing of a rotational speed of said drive motor below a predetermined level.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3, 890, 719 DATED June 24, 1975 INVENTOR(S) Albert T. Braga it is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Page 1, column 1, line 5, after "Stevensville" insert Mich,-;

Page 1, column 1, line 6, after "St. Joseph" insert Mich,--;

Page 1, column 1, line 8, delete "all of",

' Signed and Scaled this fourth Day Of November 1975 ISEAL] AIMS!) RUTH C. MASON C. MARSHALL DANN Arresting Officer (bmmissinner nflalenrs and Trademarks

Claims

1. A clothes drying machine comprising: a rotatable drum; a drive motor; a power lead for delivering power from a power source and electrically connected to said drive motor; flexible drive means coupling said drive motor and said drum for rotating said drum when said drive motor is energized via said power lead; and power-disconnect apparatus including a separable connector in said power lead, idler means in mechanical contact with and tensioning said flexible drive means, and separating means mechanically interacting together with said idler means for separating said connector in response to loss of tension from said flexible drive means.

2. A clothes drying machine comprising: a base; a housing and a drive motor mounted on said base, a power lead for delivering power from a power source and electrically connected to the motor; a drum rotatably mounted within said housing; flexible drive means driven by said drive motor and coupled to said drum for rotating said drum; and a power-disconnect system including an idler means mounted on said base and having a first position tensioning said flexible drive means and a second position wherein said idler means is in a free attitude, and means responsive to the tension of the flexible drive means for moving the idler means from its first to its second position, a separable connector, located in said power lead at some point along its length, said power lead being rigidly attached to said base at a first point on one side of said separable connector and to said idler means at a second point on the other side of said separable connector, said connector being separated in response to movement of said idler means from said first position toward said second position.

8. A clothes drying machine comprising: a base; a housing and a drive motor mounted on said base; a power lead for receiving power from a power source and electrically connected to the motor; a drum rotatably mounted within said housing; flexible drive means driven by said drive motor and coupled to said drum for rotating said drum; and a power-disconnect system including an idler means mounted on said base and having a First position tensioning said flexible drive means and a second position wherein said idler means is in a free attitude, means responsive to the tension of the flexible drive means for moving the idler device from its first to its second position, and a separable connector, located in said power lead at some point along its length, said separable connector including first and second parts, said first part being fixedly mounted in proximity to said idler means and said second part including means for contacting said idler means as said idler means moves toward its second position, whereby said parts are separated by said contact from said idler means whenever tension is removed from said flexible drive means.

10. A clothes drying machine according to claim 8, comprising a bracket mounted on said base adjacent said idler means and carrying said first connector part, and said second connector part includes an arm portion extending into the path of travel of said idler means in moving from the first position to the second position for being struck by said idler means to effect separation of said connector parts.

11. A clothes drying machine according to claim 8 having heater means for affecting the temperature in the drum and controlled by a heater circuit connected to the power source, said heater circuit including a centrifugal switch for controlling power to said heater means in response to operation of said drive motor, said centrifugal switch operating to terminate power to said heater means in response to sensing of a rotational speed of said drive motor below a predetermined level.