US3348285A - Production line - Google Patents

Description

H. E. DAY

PRODUCTION LINE 4 Sheets-Sheet 1' Filed Nov. 6, 1964 Oct. 24, 1967 H. E. DAY 3,348,285

PRODUCTION LINE Filed Nov. e, 1964 Sheets-sheet 2 INVENTOR.

/v/d fry 124?.

H. E. DAY

PRODUCTION LINE Oct. 24, 1967 4 Sheets-Sheet 5 Filed NOV. 6, 1964 INVENTOR. /ay,

Har/"y ocr. 24, 1967 H. E. DAY 3,348,285

PRODUCTION LINE Filed Nov. e, 1964 4 sheets-sheet 4 INVENTOR.

United States Patent O This invention relates to productionlines, and more particularly to constructions of a multipurpose nature for performing welding, hemming, or similar successive high.

production operations on various workpiece shapes.

The increasing proliferation of styles and models in certain products such as automobiles, has made it impracticable in many cases to build highly automated equipment for performing successive operations on subassemybles for such products, since the lesser number of subassemblies needed for each style or model often makes prohibitive the unit cost of constructing fully automated equipment. Furthermore, if highly automated equipment is constructed, the production rate of such equipment is so high that the needs for any one model would be met in a relatively short time, the equipment thus having long periods of idleness. The time required to change tools on conventional types of equipment for different subassembly styles or models is quite lengthy.

It is an object of the present invention to provide a novel and improved construction for automated production lines which will permit easy and rapid changeover to different shapes or styles of assemblies, subassemblies or workpieces upon which a successive series of operations are to be performed.

It is another object to provide an improved production line of this nature which is especially adapted for operations which use bottom action presses,

It is a further object to provide a construction of this character which may be used with parts of greatly varying length and width.

It is also an object to provide an improved production line having these characteristics, in which each fixture carries with it guide rails especially adapted to support the particular shape of subassembly upon which the fixture is intended to operate, and in which these guide rails may be extended across other stations outside the fixture, such as idle stations or table top machines.

Other objects, features and advantages of the present invention will become apparent from the subsequent description, taken in conjunction with the accompanying drawings.

In the drawings:

FIGURE l is a perspective view showing the left hand portion of a production line made according to the invention, parts being omitted for clarity;

FIGURE 2 is a perspective view showing the right hand portion of the production line, parts likewise being omitted;

FIGURE 3 is an enlarged fragmentary elevational view, parts being sectioned, taken in the area marked 3 of FIGURE l, showing the slide stroke limiting cylinders for controlling the angular positions of the lower fingers;

FIGURE 4 is an enlarged fragmentary perspective view taken in the area marked 4 of FIGURE 1 and showl ing an extractor lift cylinder;

FIGURE 5 is an enlarged fragmentary perspective view taken in the area marked 5 of FIGURE 2 and showing the guide rails in -open and folded positions as Well as a roller track and roller for a fixture;

FIGURE 6 is a fragmentary perspective view taken in the area marked 6 of FIGURE 1 and showing the means for supporting the joints between the guide rail extension sections;

FIGURE 7 is a schematic elevational view in-cross section showing the manner in which two different types of ice automobile doors could be supported by the guide rails and side guides;

FIGURE 8 is a fragmentary and partially schematic perspective view showing the operation of the stop linkage actuated by forward movement of the carriage; andV FIGURE 9 is a schematic elevational view showing the manner in which the stops are disposed within the confines of the press posts. Y v

Briefiy, the illustrated embodiment of the invention comprises a series of work stations fora workpiece such as an automobile door subassembly to which parts are to be welded or otherwise attached. Two of these work stations have bottom action presses at whichwelding operations are performed, several transfer or idle stations being disposed between the two welding stations. The

workpieces are transported from a first station which has.

a table top machine past two idle stations to the first press station, from the first press station past three idle stations to the second press station, and from the second press station to a discharge ramp. Other arrangements, such as a different number of work stations, could be made with-V in the principles of the invention.

' The workpieces are spaced apart a distance equal to their length in the direction of movement plus an additional distance, and are moved simultaneously from station to station. The movement is accomplished by an overhead transfer assembly which extends along the entire series of stations and is operated bya reciprocating motor. The assembly comprises a plurality of sets of relatively short forward and rear fingers for engaging forward and trailing portions of the workpieces respectively at some of the idle stations and the table top machine station, additional short rear fingers for pushing the workpieces at other idle stations, relatively long pusher fingers engageable with the trailing portions of the workpieces to push them into the press stations, and relatively long hook-shaped extractors engageable with the leading portions of the workpieces to pull them from the press stations.

The-fingers and extractors areprovided in pairs, that is, there are two of each of these elements at each location along the line, spaced symmetrically on opposite sides of the centerline of theproduction line. Either one or the other of these will `be used, depending upon the lateral position of the particular workpiece. If the workpiece is very wide, both fingers may be used.

The short fingers are so mounted that they may be laterally adjusted to a variety of positions, so as to engage the particular workpiece involved at its center of resistance, thereby pushing it along theV guide rails without any tendency for the workpiece to turn laterally. This arrangement is unnecessary for the pusher fingers and extractors because side guides are provided in their vicinity. Stops automatically actuated by advancing transfer mechanism movement limit the forward workpiece positions when they are advanced by the additional short fingers, pusher fingers and extractors.

The stroke length of the transfer mechanism is constant regardless of -the workpiece size and is equal to the length of the workpiece plus the distance between workpieces. Therefore, whatever the size of the workpiece in its direction of movement, the point or points at which it is engaged by the advancing elements of the transfer mechanism at the beginning of each stroke will always be in the same position at each work station. The construction of the fixtures is calculated by using this point to determine a reference line. For example, in the case of an automobile door, this reference line could pass through or be included in a surface which supports the lock or the hinge. In any case, the surface including the reference line will be on the trailing portion of the workpiece.

Each press station has a bottom action press with a bed and an upper platen fixedly supported above the bed by four posts at the corners thereof. Means are provided for alternately positioning two or more fixtures in each bottom action press. This means includes a pair of laterally extending roller tracks immediately below the upper press platen, the tracks extending to one or both sides of the press. The desired fixtures are mounted on these tracks by means of rollers, so that any fixture may be rolled into position within the press, the others being rolled out of position.

Each press further comprises a lower platen above the bed which is vertically movable by appropriate motor means and on which rests the lower plate of the fixture. Each fixture comprises upper and lower plates connected by telescoping vertical guide posts. These plates are secured to the press platens, and the upper plate carries guide rails below it for slidably supporting the workpieces. Means are provided on the die carried by the lower fixture plate for lifting a workpiece resting on the guide rails when the lower press platen is raised.

The guide rails on each fixture comprise tubular members secured to the upper or fixed portions of the telescoping guide posts. Preferably, folding guide rail extension sections are provided, these having an articulated connection with the fixed guide rail sections on the fixture and being movable from a folded position within the confines of the fixture to an extended position in which they serve as guide rails at the adjacent work or idle stations of the production line. Short lengths of semicircular tubing are provided for supporting the oldable guide rail sections in their extended position. When in their folded position, the guide rails will clear the press posts so that the entire fixture may be rolled into or out of position.

When the lower fixture plate is raised by the lower press platen, it will lift the workpiece off the .guide rails and support it in position for the welding operation, the welding guns being secured to the upper plate of the xture. After the welding is completed, the guns will be retracted and the press platen retracted downwardly, the workpiece being again brought to rest on the gui-de rails so that it may be advanced to the next station.

The pusher lingers are provided with retracting motors for clearing the workpieces when they are raised and when the reciprocating transfer mechanism is retracted for the next stroke. Similarly, the short fingers and the extrae tors are swingable out of their normal position for the retracting stroke of the transfer mechanism.

Each of the alternately usable fixtures at each press station will of course have its own welding gun or other tool arrangement as well as its own arrangement of guide rails to conform to the contour of the particular workpiece to Ibe operated upon. The transfer mechanism will be the same regardless of the type of workpiece. It is thus possible to quickly change from the production of one workpiece or subassembly to that of another by merely folding the guide rails of the fixture to be removed, detaching the fixture from the press platens, removing the fixture by rolling it along the roller tracks, rolling the new fixture into position, attaching it to the press platens, and unfolding its guide rails.

Referring more particularly to the drawings, FIGURES 1 and 2 show adjacent portions of a complete production line constructed according to the invention, and should be studied by positioning the figures in horizpntal alignment with FIGURE l to the left of yFIGURE 2. The production line shown in FIGURES l and 2 has eight stations. The first station, generally indicated at 11, has a table top machine generally indicated at 12, this machine being of a type which may support a workpiece for any of a variety of operations. A typical use would be to mount weatherstripping elements Iby welding them onto an automobile door subassembly. Machine 12 is moutned on laterally extending rails 13 so thatV it may be moved out of position and another machine, or a guide for an idle station, inserted in its place. Machine 12 is provided with guide rails 14 which are so positioned as=to conform to the contour of the workpiece 15 which it is intended to carry.

The next station, generally indicated a-t 16 in FIGURE l, is an idle station, and has an A-frame support 17 for guide rails which extend from the fixture at the nearest press station, these guide rails being described in detail below. For a particular workpiece 15, of course, the guide rails supported by frame 17 will be aligned with the guide rails on whatever machine is placed at station 11.

The next station is generally indicated at 1S and is also an idle station, resting on a support bracket 19 secured to the press of the adjacent station. Station 18 is provided with side guides 21 for guiding the workpieces and with guide rails for supporting the workpieces. Side guides 21 and the guide rails, described below in greater detail, cornprise extended sections which are foldably connected to the fixture at the press station.

The first press station is indicated generally at 22. and comprises a bottom action press generally indicated at 23 and any one of a number of fixtures, one such fixture being indicated generally at 24 in FIGURE l. Press 23 is of a conventional type, having a bed 25 and four posts 26 extending upwardly frorn the corners thereof, an upper platen 27 being secured to the upper ends of the posts. A lower platen 28 is provided above bed 25, this platen being vertically movable by motor means (not shown) to which it is connected by toggle crank linkage means 29. These crank linkage means are movable from the folded position shown in FIGURE l to an extended or overcenter position holding lower platen 28 in an upper position so that the welding operations may take place. One or more auxiliary cylinders 30 may be provided under platen 28 for assisting in lifting and holding the platen in position. Guide rollers indicated partially at 31 are carried by lower platen 28 and are engageable with posts 26.

Following station 22 there are three idle stations designated generally at 32, 33 and 34 in FIGURES l and 2. These idle stations are disposed between station 22 and a second press station generally indicated at 35, and are formed by outwardly extending support brackets 36 and 37 secured to stations 22 and 35 respectively. The guide rails for supporting workpieces 15 along these idle stations are mounted on the fixtures 24 and 38 within welding stations 22 and 35 respectively, and are foldable in a manner hereinafter described to positions confined within their respective fixtures so that the fixtures may be removed from or installed in the press stations.

Station 35 is constructed similarly to station 22 and need not be described in detail. However, FIGURE 2 shows two fixtures 38 and 39 provided for welding station 35, fixture 38 being mounted in the station and fixture 39 away from the station.

The manner in which the fixtures are removably mounted in their respective press stations will now be described. Referring to FIGURE 5, the upper platen 27 of each press (press 23 at station 22 and the press generally indicated at 41 at station 35), has on its underside a pair of parallel rail supports 42 and 43. These are channel-shaped members with their open sides facing each other, and roller tracks 44 are mounted on the insides of the lower iianges thereof. These roller tracks are adapted to support the four rollers 45 which are provided at the corners of the upper plate 46 of each fixture.

Each fixture also has a lower plate 47, the plates being connected by telescoping posts 48. These posts are secured to pedestals 49 fixed to plate 47 and slide in downwardly extending guides 51 secured to plate 46.

Means indicated partially at 52 in FIGURES l and 2 is provided for securing the fixture in its collapsed position, that is, with posts 48 telescoped into guides 51. Lower plate 47 of each fixture when in its operative position is adapted to rest on lower platen 2S of its corresponding press. Means indicated partially at 53 are provided on the upper platen of each press for drawing upper plate 46 of a fixture disposed thereunder upwardly toward plate 27, and securing it in such position. In this secured position, rollers 45 are spaced slightly above tracks 44. With elements 52 in locked position and elements 53 released, a fixture may be rolled along tracks 44 into or out of its corresponding press.

Each fixture also carries a plurality of welding guns 54, transformers 55 and other equipment needed for the welding operation.

The construction of the guide rails carried by the fixtures is perhaps best seen in FIGURES 5, 6 and 7. As indicated previously, the straight guide rails will together form different configurations from fixture to fixture to accommodate various workpiece configurations with which they are intended to be used. Brackets 56 are secured to guides 51 fixed to upper plate 46 and carry angle members 57 extending in the direction of movement of the workpieces. Cross straps 58 extend between the ends of the angle members on opposite sides of the fixture, and the angle members and end straps support a plurality of tubular members 59, 61, etc. in parallel relation, these members being secured to the xture. The height and spacing among tubular members 59, 61, etc. are such as to form in cross section the proper configuration for supporting the workpiece. Angle members 57 and tubular members 59, 60, etc. all terminate within the confines of posts 26 of the press, so that they will not interfere with the movement of the fixture into or out of its operative position. Cross straps 58 and tubular members 59, 61, etc, are so positioned as not to interfer with the lower fixture die (not shown) resting on plate 47 which lifts workpiece 15 during its upward movement.

FIGURE 7, for example, shows two possibilities. In solid lines we see a schematic showing of an automobile door 15 having a header, that is, a frame for a window. The rails 59, 61 and 61 are so positioned as to support the door in a cradled manner, with members 57 acting as side guides which are of course secured to the fixture. The center of resistance of such a door might be such that finger 103, described below, would be most effectively positioned when it is vertical, as indicated at 10'3 in FIGURE 7.

If the door does not have a header (for example, if it is intended for a hard-top car), it will end at the dotted line indicated at in FIGURE 7. In such case, the left hand glide rail 57 would be at the location marked 57, and only two guide rails might be required indicated at 61" and 61 in FIGURE 7. Also, the center of resistance might be such that finger 103 would be most effectively used if it is in the position marked 103m. The area 130 indicates a lateral location of a pusher finger with respect to such a workpiece. The pusher finger is described below.

A short link 62 is connected at one end by a pivotal tongue-and-,groove connection 63 to each end of each member 59, 61, etc. for which an extension is to be provided. This short link 62 may swing between the upper or folded position shown in FIGURE 5 and a lower position aligned with its corresponding fixed guide rail, being supported in this lower position by a semi-cylindrical mem'ber 64 secured at one end to the fixed guide rail and extending outwardly therefrom.

The other end of link 62 has a semi-cylindrical member 65 secured thereto, and an extension guide rail 66 is pivoted to that end of link 62 by a tongue-and-groove connection 67. In its folded position, extension 66 is folded back upon its corresponding fixed guide rail, and in its extended position is aligned with the fixed guide rail and the link 62, being supported by the outer end of semicylindrical member 65.

FIGURE 6 illustrates the manner in which a plurality of contiguous rail extensions may be supported on frame 17 or on a support bracket such as those indicated at 32, 36 and 37. A bed 68 is provided on the frame or bracket, and a nest block 69 is secured thereto for each two adjacent guide rails, this block being of L-shaped cross section and having a spring-loaded locking block 71 thereon, this locking block being slidingly mounted on block 69 and 6 urged by springs (not shown) toward the upstanding portion of block 69. A rail lock finger 72 is provided for each guide rail, this finger having a lower portion releasably disposed between members 69 and 71 and extending upwardly therefrom, the two members 72 in each block 69, 71 extending in opposite directions, as seen in FIGURE 6. The uper portion of each finger 72 has a semi-cylindrical member 73 secured thereto. Fingers 72 may be positioned so that members 73 will support the pivoted tongueand-groove joints 74 between each extension 66 and its additional extension 75. The arrangement is therefore such that the extensions may all be folded back on each other so as to be within the confines of the fixture, but when in extended position will be aligned and fully supported. As seen in FIGURE 2, the guide rail extensionsY from adjacent fixtures will be in abutting relation, so as to provide a smooth and uninterrupted guiding surface for the workpieces as they move from the first press station 18 through the idle stations to the second press station 35. In order to assure proper alignment of the guide rails, a fixture locking cylinder 76 is provided on the upper platen of each press, this cylinder operating a bolt (not shown) movable in a direction parallel to the direction of movement of ther workpieces, and receivable by a keeper 77 on the upper plate 46 of each fixture, as seen in FIGURE 5.

The side guides 21 for the idle stations are also shown as being pivoted to the fixed side guides 57; this pivotal connection is indicated at 21' in FIGURES l and 5. Additional extensions could be pivoted to sections 21. The side guides would thus be foldable to positions within the confines of the fixture at the same time that the rail extensions are so that the fixture may be moved into or out of the press station.

Referring now to the means for moving workpieces 15 along the guide rails, a plurality of posts 78 are provided along the assembly line and outwardly of the path` of movement of the workpieces, these posts supporting an elongated framework 79 which forms parallel rails, as

seen in FIGURES 1 and 2. A transfer drive cylinder 81v is mounted at the forward end of frame '79 on one side thereof and is connected to a frame 82 which rotatably supports a tooth pinion 83. The lower side of this pinionv meshes with an upwardly facing rack 84 fixed to frame 79, and the upper side of the pinion meshes with a downwardly facing rack 85 secured to a transfer carriage 86. This transfer carriage rests on the rails of frame 79 by means of rollers 87, so that, for example, when frame 82 and pinion 83 is pushed to the right in FIGURE 2 by motor 81 at a certain speed, carriage 86 will move to the right at twice the speed of pinion 83. Similarly, when frame 82 and pinion 83 are moved to the left, carriage 86 will move in the same direction at twice the speed of pinion 83.

A second transfer carriage 88 is provided on an intermediate portion of frame 79, this carriage being connected with carriage 86 by a tie rail 89. Carriage 88 has rollers 91 which support it for movement along frame 79.

A third transfer carriage 92 is mounted on the left hand end of frame 79, as seen in FIGURE l, by means of rollers 93, and is connected with carriage 88 by means of a tie rail 94. Therefore, all three carriages`86, 88 and 92 will move in unison as driven by motor 81.

Carriages 88 and 92 are each provided with a finger supporting frame generally indicated at 95 whic-h carries the various workpiece-engaging elements. Each frame has a pair of downwardly extending columns 96 secured at their upper ends to their respective carriage, and a downwardly and rearwardly inclined member 97, the lower ends of these frame members being connected by a horizontal member 98.

A forward and a rear finger bar supporting block, designated at 99 and 101 respectively, in FIGURE 1, are secured to each side of the lower portion of each r frame 95. Each pair of blocks 99 and 101 rotatably supports a finger bar 102 which extends alongside frame member 98. This bar is of non-circularcross section, and a rear or trailing finger 103 is secured to the rear end of each bar. Fingers 103 extend downwardly and are adapted to engage the trailing edges of workpieces 15, the fingers having intermediate horizontal portions for extendingthe effective rearward position of fingers 103. Fingers 103 are fixed to their respective bars 102. A forward finger 104 is slidably but non-rotatably mounted on an intermediate portion of each bar 102, between blocks 99 and 101 thereof. The position of each finger 104 along bar 102 is determined by the rotation of a lead screw 105 rotatably mounted on frame 95 alongside bar 102. This lead screw carries a nut 106 with a downward extension 107 rotatably connected to the forward end of finger 104.

The position of nut 106 on lead screw 105 is determined by a reversible motor 108 which drives a countershaft 109 rotatably supported by and extending between carriages 92 and 8S. A motor 108 is provided for the lead screws 105 on each side of the unit, and countershafts 109 are rotatably supported by bearings 111 carried by cross beams 112 mounted on tie rail 94, as well as by gear boxes 113 on carriage 92 and gear boxes 114 on carriage 88.

Gear boxes 113 and 114 contain bevel gears (not shown) which connect the countershafts with vertical shafts 115, `the lower ends of the vertical shafts leading to gear boxes 116 having bevel gears which connect them with lead screws 105. Rotation of either motor 108 will therefore simultaneously adjust both forward fingers 104 toward or away from its rear finger 103. This adjustment will be made so as to nest the workpiece 115 between the forward and rear fingers.

When the lingers 103 and 104 on either side of frames 95 are actually transporting workpieces 15, they will be in the vertical positions shown in FIGURES 1 and 2, or in an angularly adjusted position. Means are provided for retracting the fingers upwardly at the forward end of each stroke, this means also including means for adjusting the angular position of the fingers when in their transporting position so as to accommodate workpieces of varying widths and push these workpieces at approximately their center of resistance to avoid lateral motion thereof. More particularly, when viewing .fingers 103 in FIGURE 1 at the extreme trailing end of the machine, the left hand finger 103, when in its transporting position, may be in either of two positions which are located clockwise of the vertical position shown, and on the retracting stroke, may be swung to a completely horizontal position so as to be above and clear workpieces (see also FIGURE 7). Similarly, the right hand finger 103 could either be in its vertical position as shown in FIGURE l, or in either of two positions spaced angularly in a counterclockwise direction from the FIGURE l position when it is transporting a workpiece, and will be swung counterclockwise 90 to a horizontal position when it is being retracted. The other two operative positions of the right hand finger 103 at the trailing end of the production line in FIGURE l, are indicated schematically in dot-dash lines at 103a and 103b, while the retracted position is indicated at 103C. Since forward fingers 10'4 are nonrotatably connected to bars 102 they likewise will be capable of the three other positions described with respect to fingers 103.

An additional finger 117 is secured to each bar 102, this finger serving the same purpose as finger 103 but for the station next ahead on the production line. Finger 117 is not adjustable along bar 102, nor does it have a corresponding forward1M finger similar to finger 104. It too, however, will be'adjustable to the various angular positions described with respect to fingers 103 and 104.

Each fixture is provided with a stop 118 automatically movable from a retracted to an operative position by linkage, described in detail below but indicated partially at 119, in response to forward movement of the transfer carriages, to limit forward movement of the workpiece by a finger 117. Stop 118 is retractable by linkage 119 in response to rearward movement of the carriages.

The means for selecting the angular position of fingers 103, 104 and 117 are seen best in FIGURES l and 3. Each bar 102 has a crank arm 102 secured thereto, and a pair of links 121 connects each pair of crank arms with a vertically movable slide 122 mounted on the rearwardly facing surface of the rearward post l96- of each frame 95. A uid actuated reciprocable motor 123 is vertically mounted on this post 96 above slide 122, its piston rod 124 being connected thereto as seen in FIGURE 3. A stop 125 secured to post 96 limits the lowermost position of slide 122, this position being such that fingers 103, 104 and 117 will be in their vertical positions as shown in the drawings. A pair of cylinders 126 and 127 are secured to the forward side of post 96 and actuates stops 128 and 129, respectively, .between retracted position as shown in FIGURE 3 and operative positions extending to the left of those shown in FIGURE 3. When piston rod 124 is completely retracted upwardly, slide 122 will be raised to a point at which fingers 103, 104 and 117 will be horizontal, as indicated schematically at 103e for finger 103, thus clearing the workpieces 15. If stop 128 is extended to the left in FIGURE 3, stop 129 being retracted, downward movement of piston rod 124 will cause slide 122 to engage stop 128. At this position, fingers 103 will -be in the position indicated schematically at 103b, and fingers 104 and 117 will be similarly positioned. Should stop 128 be retracted and stop 129 extended to the left, slide 121 will be permitted to move down to a position in which fingers 103 will be in the 103a position, with fingers 104 and 117 similarly positioned. It will be noted that except for very wide workpieces, only the left or the right hand fingers will actually be in use, although the other set of fingers will swing at the same time between retracted and operative positions because the bars 102 on both sides of frame 95 are connected to slide 122.

Two relatively long pusher fingers 130 on opposite sides of the production line are carried by the forward ends of each frame 95 for alternate or simultaneous use in pushing workpieces from idle station 18 to press station 227 and from idle station 34 to press station 35. Each pusher finger is movably connected at 131 to a cross bar 132 mounted on the forward end of frame 95 and eX- tends forwardly and downwardly therefrom when in its operative position. A fluid-operated reciprocable motor 133 is provided for each pusher finger 130. This motor is connected by cam slot-and-follower means (not shown) to finger 130 in such manner as to move it between the operative position shown and a retracted position which is preferably slightly rearwardly of the operative position and swung upwardly to a horizontal position. The slight rearward movement of the pusher finger may be required to clear a rearwardly projecting lip at the lower portion of the trailing edge of a workpiece such as an automobile door subassembly. The horizontal position of pusher finger 130, when retracted, will enable the entire transfer assembly to be retracted to the left in the figures in readiness for the next transfer stroke. Each fixture is provided with an automatically actuatable stop (described below) similar to stop 118 for limiting the forward movement of workpieces advanced by pusher 130 into the press station.

Two alternately or simultaneously usable extractors 134 are provided on opposite sides of the production line for removing workpieces 15 from press station 22. The extractors are mounted on the rearwardly facing portion of member 97 on frame 95 which depends from transfer carriage 88. As seen in FIGURE 4, each extractor cornprises a bar pivotally connected by a pin 135 to a bracket 136 on the upper portion of a frame 137 which encloses an extractor lift cylinder 138. The lower end of the extractor is hook-shaped so as to be capable of engaging the workpiece when in its operative position and pulling the workpiece out of the work station. The upper end of the extractor has an extension 139 which is en- 9 gageable by the end of a piston rod 140 actuated by fiuidoperated motor 138. When piston rod 140 is moved to the left in FIGURE 4, extractor 134 will be swung clockwise about pin 135 to a retracted position, whereas retraction of piston rod 140 will permit the extractor to return to its operative position. The fixtures carry stops, described below, similar to stops 118 for limiting the advancing movement of the workpieces by extractors 134.

It should be noted that neither pusher fingers 129 nor extractors 134 are adjustable laterally so as to be aligned with the center of resistance of the workpieces. This is unnecessary in view of the fact that workpieces 15 when engaged by these transfer members will also be guided by side guides 21.

A stripper seen partially at 141 in FIGURE 2 is mounted in each fixture to be received by press 41. This stripper is actuable through a one-way connection by a reciprocable fluid-actuated motor (not shown) to push workpieces 15 from station 35 onto a discharge ramp 142. Stripper 141 may be pivotally mounted s0 as to permit workpieces being advanced by pusher 130 to ride over it into station 35.

FIGURES 8 and 9 show the arrangement for automatically raising and retracting the stops which limit advancing movement of the workpieces engaged by fingers 117, pushers 130 and extractors 134. This mechanism has been omitted from FIGURES 1 and 2 for purposes of clarity. A laterally extending bar 143 is secured to the lower end of a frame 95, and carries an angle member 144 to the underside of which is secured a cam 145. This cam has a sloping portion 146 and a straight portion 147 and is adapted to engage a rod 148 secured to the rear end of a shaft 119. This shaft is rotatably supported by brackets 149 secured to and extending laterally outwardly from the lower edge of one of the stationary side guides 57 secured within each fixture. Three arms, 151, 152 and 153 are secured to shaft 119 and extend inwardly therefrom, the ends of these arms carrying stops 118, 154 and 155 respectively. The positions of these stops along shaft 119 are such that, as shown in FIGURE 9, they will be adapted to stop workpieces 15 moved by members 117, 130 and 134 respectively, as the carriage mechanism reaches the end of its stroke.

The entire stopping mechanism including elements 148, 119 and 149 through 155, are within the confines of the fixture and thus will be removable and insertable therewith with respect to the work station. For this purpose, stop 155 is positioned so as to be engageable by a fiange 156 on the trailing portion of the workpiece being removed by extractor 134.

The movement of stops 118, 154 and 155 will be between the upper or operative stopping position indicated in solid lines in FIGURE 8, and a lower or retracted position indicated with respect to stop 118 by dot-dash lines. This movement will ensue from the fact that when the carriage mechanism is in its retracted or rearward position, cam 145 will be separated from rod 148 and the weight of arms 151 to 153 will cause counterclockwise rocking of the stop assembly, with rod 148 engaging a limiting member 157 secured to side guide 57. As the carriage mechanism advances in the direction of arrow 158 in FIGURE 8, surface 146 of cam 145 will first engage rod 148, rocking the stops upwardly, in which position they will remain as rod 148 rides on surface 147 of the cam. It will thus been seen that cam 146 will coact with rod 148 on any fixture, the positions of the workpiece stops being adjustable in the direction of movement of the workpieces on differentV fixtures to compensate for varying workpiece lengths and shapes.

In operation, welding stations 22 and 35 will be provided with the desired fixtures, the fixtures rolling along tracks 44 by means of their rollers 45 and being locked in position utilizing the locks operated by cylinders 76 which enter keepers 77. The upper plates 46 of the fixtures will be secured to upper platens 27 of their respective presses by -means of fasteners 53, lifting rollers 45 slightly off tracks 44, and locks 52 will be released so that posts 48 of the fixtures may telescope into and out of guides 51. With the lower plates 47 of the fixtures secured to lower platens 28 of the presses, guide rail extensions 66 and 75 may be unfolded to their aligned positions, being supported by members 64, 65 and 73, as described above.

Let us assume that workpieces 15 are in position on the guide rails with their lateral position determined by the cradled nature of the guide rails or by side guides 57 and extensions 21. Let it be further assumed that the transfer mechanism is initially in the position shown in FIGURES 1 and 2, with fingers 103, 104 and 117 angularly adjusted, as indicated at 103a, 103b for fingers 103, in accordance with the center of resistance of the workpiece, by vertically adjusting slides 121 as controlled b v stops 128, 129 or 125. Piston rod 81 will be actuated to the right in FIGURE 2, pulling transfer carriages 86, 88V

and 92 to the right along the rails formed by frame 79. This will push workpieces 15 a distance equal their length plus the distance between them so that they will arrive at the next station. During this transfer movement,'thev workpiece -at station 11 will be held by fingers 103 and 104, it being kept in mind that unless the workpiece iS fairly wide, only the fingers to the left or to the right willV be used in any one operation. The workpiece at station 16 will be pushed by a finger 117 and the workpiece at station 18 by a pusher 130. At station 22, the workpiece will be pulled toward station 32 by an extractor 134. A workpiece will be transferred from station 32 to station 33 by a set of fingers 103 and 104, and from station 33 to station 34 by a finger 117. The workpiece at station 34 will be moved to station 35 by a pusher 130 and thev workpiece at station 35 will be pushed by stripper 141 onto discharge ramp 142. v

After the forward stroke of the transfer mechanism has been completed, slides 121 will be pulled upwardly by motors 122, retracting fingers 103, 104 and 11'/ to their retracted position, as indicated at 103e` for finger 10-3. -Pushers 130 will be pulled vrearwa-rdly and upwardly by motors 133, and extractors 134 will be swung upwardly into retracted position by extension of piston -rod 140. IPinion 8,3 will then be drawn to t-he left by piston rod 81, moving the transfer carriages and their attached parts to the left in readiness for the next advancing stroke.

Meanwhile, the operator at each press station 32 andV 35 will place parts to be welded to the workpiece in proper position. Each press platen 28 will be moved upwardly by its actuating mechansm which is not fully shown but includes links 29 .and cylinders 30. This will raise lower plate 47 of each fixture, causing the workpiece resting on the guide rails above to be lifted from the guide rails. The workpieces will belifted off the guide -rails with the parts to .be welded thereto still resting on them. When links 29 have reached an overcenter position, welding guns 54 will be extended, welding the parts to the workpiece. The welding guns will then be retracted.

Platens 28 of presses 23 and 41 will then be lowered, causing the workpieces to be again lowered onto the guide rails. Fingers 103, 104 and 117 as well as pushers 130 and extractors 1134 will again be moved to their operative position and the transfer mechanism again actuated to move the workpieces to their next stations.

The system of course permits the inclusion of any desired number of work stations in the production line. Should it be desired to change the production line to operate on a workpiece having a different shape or style, or requiring different welding or metal forming operations, the fixtures in one or both of the presses shown may be removed and alternate fixtures placed therein. Removal of a fixture is accomplished by first folding guide rail extensions 66 and-75 and side guides 21 which are connected to the fixed guide rails and side guides respectively on the fixture to collapsed positions within the confines of the fixture. The corresponding press platen 28 is raised until the upper guides 51 of the fixture may be secured to the lower posts 29 thereof by locks 52. The lower plate 47 of the fixture is then detached from lower platen 28 of the press and the upper plate 46 detached from upper platen 27 of the press. The latter detachment will permit rollers 45 of the fixture to be lowered onto tracks 44.

Platen 2S of the press is then rlowered and the fixture isl ready to be removed.

While it will be apparent that the preferred embodiment of the invention disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning o-f the subjoined claims.

What is claimed is:

1. -In a production line having at least one work station with vertically spaced and relatively movable tool and workpiece supports, an overhead transfer mechanism mounted above the line, means for repeatedly advancing and retracting said transfer mechanism along the path of the movement of the workpieces, downwardly extending portions on said transfer mechanism disposed forwardly and rearwardly of said station and having elements engageable with said workpieces to move `them along the production line, means for moving said elements between upper retracted positions and lower operative lpositions in which the elements engage the workpieces, means for advancing said transfer mechanism while said elements are in their operative positions, means for retracting said transfer mechanism while said elements are in their retracted positions, at least one fixture for said station, and a track at the upper portion of said station and extending transversely thereto, said fixture being mounted on said track for movement into and out of said station.

2. rl'he combination according lto claim 1, further provided with workpiece-supporting guide rails having portions fixedly secured to said fixture, and extensions for said guide rails movably secured thereto -and adjustable between operative positions aligned with. their respective fixed portions and folded positions within the confines of said fixture.

3. The combination according to claim 1, further provided with stops on said fixture movable between retracted and operative positions, and coacting means on said downwardly extending transfer mechanism portions and on said fixture responsive to advancing movement of s-aid transfer mechanism to move said stops to their operative positions and responsive to retracting movement of said transfer mechanism to permit movement of said stops to thei-r retracted positions, the stops and the portion of said coacting means on said fixture being disposed within the confines of said fixture, whereby they will be in non-interfering relation with the compounds of said station when the fixture is moved into and out of the station.

4. The combination according to claim 3, said coacting means comprising a shaft rock-ably mounted on said fixture, arms secured to said shaft and carrying said stops at the outer ends thereof, and a cam on said downwardly extending transfer mechanism portion engageable with anothe-r arm secured to said shaft.

5. In a production line having at least one bottom action press at a first station with a fixed bed and upper platen and a movable lower platen, a second station rearwardly of said press, and a third station forwardly of said press, the press having corne-r posts connecting the bed and upper platen thereof, roller tracks secured beneath the upper press platen and extending transversely thereto, at least one fixture for said press having upper and lower plates securable to the upper and lower pla-tens respectively of said press, rollers secured to said upper plate and rollable on said roller tracks, and workpiece transfer carriage means mounted above said stations.

6. The combination according to claim 5, further provided with telescoping vertically disposed connections be- Vtween said upper and lower plates having upper portions fixed to said upper plate, workpiece guide rails having portions fixed to said last-mentioned portions, and extensions for said guide rails pivotally secu-red to said fixed guide rail portions and movable between operative positions aligned with the fixed guide rail portions and folded positions within the confines of said fixture, whereby the fixture may clear the press posts when moved into and out of the press.

7. The combination according to claim 6, further provided with workpiece side guides having portions fixed to the upper portions of said telescoping connections, and extensions for said side guides movably secured to said fixed side guide portions and movable between operative positions aligned with the fixed side guide portions and folded positions within the confines of said fixture.

8. The combination according to claim 5, further provided with an overhead iframe extending along said production line above said stations, said transfer carriage means being movably mounted on said overhead frame, means for reciprocating sai-d transfer carriage means a distance greater than the length of the longest workpiece to be carried by said production line, portions extending downwardly from said transfer carriage means forwardly and rearwardly of said press, a pusher finger on the portion which is disposed rearwardly of the press, said pusher finger extending forwardly toward said press, means for moving said pusher finger between an operative position in which it is inclined forwardly and downwardly, and a retracted position above said operative position, an extractor carried by the downwardly extending portion of sai-d transfer mechanism which is disposed forwardly of said press, said extractor comprising a rearwardly extending member, and means for moving said extractor between an operative position inclined rearwardly and downwardly and a retracted position above said operative position.

9. The combination according to claim 8, said fixture being further provided with stops for wor-kpieces engaged by said pusher finger and extractor to limit the advancing movement thereof, and coacting means on said transfer carriage means and said fixture for moving said stops to operative positions in response to advancing movement of said transfer carriage means and to retracted positions in response to retracting movement of said transfer carriage means.

1t). The combination according to claim 5, said production line being further provided with a fourth station rearwardly of said second station, the downwardly extending portion of said transfer mechanism disposed rearwardly of said press further carrying a finger for engaging a workpiece at said last-mentioned station and moving it 4to said second station, and means fo adjustably positioning said finger in a variety of laterally spaced positionsfor engagement with workpieces having centers of resistance at various locations.

11. The combination according to claim 10, said lastmentioned means comprising a bar extending in the direction of movement of said workpieces and rotatably carried by said downwardly extending transfer mechanism portion, said finger being attached to said bar, and means for rotating said bar about its axis including a crank fixed to said bar, a slide carried by said downwardly extending transfer mechanism portion, alternately actuatable stops for limiting the movement of said slide, and a link connecting said slide with said crank.

12. The combination according to claim 11, said production line being further provided with a fifth station rearwardly -of said fourth station, forward and rear fingers mounted yon said bar for moving a workpiece from said fifth station to said fourth station, said rear finger being secured to said bar, and means for adjustably positioning said forward finger along the Ilength of said bar to accommodate workpieces having vari-ous lengths in their direction of movement.

13. The combination according to claim 12, said last-mentioned means comprising a lead screw mounted on said downwa-rdly extending transfer mechanism portion parallel to said bar, means carried by said transfer mechanism for rotating said lead screw, and a connection between said lead screw and said forward finger.

14. The combination according to claim 12, said bar being on one side of said downwardly extending transfer mechanism portion, another bar on the other side of said downwardly extending transfer mechanism portion, another linger fixed to said last-mentioned bar, ya crank on said last-mentioned bar, and a link connecting said last-mentioned crank with said slide, whereby movement of said slide will simultaneously adjust the lateral positions of both of said fingers.

15. The combination according to claim 14, said slide being further adjustable to a position in which said lingers are retracted upwardly a suficient distance to clear said workpieces.

16. In a production line, a plurality of Work stations in spaced relation, a transfer mechanism extending above said work stations, said transfer mechanism comprising a frame having a rail, transfer carriage means movably mounted on said rail, means for reciprocating said carriage means in unison, a first structure depending from said carriage means on one side of `one of said work stations, a second structure depending from said carriage means `on the other side of said work station, a pusher finger carried by the first depending structure and adapted to push a workpiece into said work station when the carriage means moves in one direction, an extracto-r carried by the other depending structure and adapted to pull a workpiece from the work station when the carriage means moves in the same direction, said depending structures each -being provided with a horizontally extending finger-supporting bar, means for rotating said bars to a variety of angular positions about their own axes, at

least one conveyor finger slidably but nonrotatably mounted on each bar, stop means for limiting the forward movement of a workpiece pushed by each of said fingers, and linkage means responsive to forward movement of said carriage means for moving said stop means from la retracted position to an operative position.

17. A work station for a production line comprising a bottom action press having a bed, a fixed upper platen, and a vertically reciprocable lower platen, roller tracks mounted below said upper press platen and extending transversely thereof, a fixture comprising a lower plate and an upper plate, rollers carried by said upper plate and mounted on said roller tracks, whereby the -fixtures may be rolled into and out of position with respect to said press, telescoping members at the corners of said fixture plates whereby the plates may be moved together or apart, means for locking the telescoping members in a collapsed position, means for attaching the upper fixture plate :to the upper press platen, said last-mentioned means including means for drawing the upper fixture plate upwardly so that its rollers will be lifted from the roller tracks, coacting means on the press and upper fixture plate for locking the fixture in its operative position whereby it may not be moved laterally, reciprocating means mounted above said production line and having portions depending therefrom rearwardly and forwardly of said press, workpiece moving means carried by said depending portions, workpiece stops carried by said fixture, and coacting means on said reciprocating means and said fixture responsive to forward movement of said reciprocating means to move said stops to operative positions with respect to said workpieces.

No references cited.

RICHARD EANES, JR., Prz'maiy Examiner,

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTIGN Patent No. 3,348,285 October 24, 1967 Harry E. Day

It is hereby certified that error appears in the above numbered patent requiring correction and that Jhe said Letters Patent Should read as Corrected below.

Column l, lines 1S and 16, for "subassembles" read subassemblies column 3, line 71, for "moutned" read mounted column 5, line 25, for "60" read 61 Column 6, line 7 for "uper" read upper Column 8, line 6, for "crank arm 102l read crank arm 120 Column 12, line 53, for "fo" read for column 14, line 12, for "fixtures" read fixture Signed and sealed this 19th day of November 1968.

(SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD BRENNER Attesting Officer Commissioner of Patents

Claims (1)

1. IN A PRODUCTION LINE HAVING AT LEAST ONE WORK STATION WITH VERTICALLY SPACED AND RELATIVELY MOVABLE TOOL AND WORKPIECE SUPPORTS, AN OVERHEAD TRANSFER MECHANISM MOUNTED ABOVE THE LINE, MEANS FOR REPEATEDLY ADVANCING AND RETRACTING SAID TRANSFER MECHANISM ALONG THE PATH OF THE MOVEMENT OF THE WORKPIECES, DOWNWARDLY EXTENDING PORTIONS ON SAID TRANSFER MECHANISM DISPOSED FORWARDLY AND REARWARDLY OF SAID STATION AND HAVING ELEMENTS ENGAGEABLE WITH SAID WORKPIECES TO MOVE THEM ALONG THE PRODUCTION LINE, MEANS FOR MOVING SAID ELEMENTS BETWEEN UPPER RETRACTED POSITIONS AND LOWER OPERATIVE POSITIONS IN WHICH THE ELEMENTS ENGAGE THE WORKPIECES, MEANS FOR AD-

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