US2642179A

US2642179A - Transfer apparatus

Info

Publication number: US2642179A
Application number: US763531A
Authority: US
Inventors: Ralph E Cross
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-07-25
Filing date: 1947-07-25
Publication date: 1953-06-16
Anticipated expiration: 1970-06-16

Description

June 16, 1953 v c oss 2,642,179

TRANSFER APPARATUS Filed July 25, 1947 8 Sheets-Sheet 1 June 16, 1953 R. E. cRoss 2,642,179

TRANSFER APPARATUS Filed July 25, 1947 8 Sheets-Sheet 2 F 4/21 Crass.

BY Ma?" June 16, 1953 R. E. CROSS 2,642,179

TRANSFER APPARATUS Filed July 25, 1947 s Sheets-Sheet 3 R4475 Crass.

June 16, 1953 R. E. cRoss TRANSFER APPARATUS 8 Sheets-Sheet 4 Filed July 25, 1947 I TOR/VEKST June 16, 1953 E. @055 2,642 179 TRANSFER APPARATUS Filed July 25, 1947 8 Sheets-Sheet 5 20: w me IN V EN TOR. fia/yl 1 Cross.

raga/ m.

R. E. CROSS TRANSFER APPARATUS June 16, 1953 s Sheets-She et 6 Filed July 25, 1947 INVENTOR. J Crass" June 16, 1953 312055 2,642,179

TRANSFER APPARATUS A Filed July 25, 1947 8 Sheets-Sheet 7 IN V EN TOR. fiaZv/F J. Cramv June 16, 1953 R. E. CROSS TRANSFER APPARATUS Filed July 25, 1947 8 Sheets-Sheet 8 )mw B w w g Q I W A J'lih o I J N R 0 W Patented June 16,

OFFICE TRANSFER APPARATUS Ralph' E., Cross, Grosse Pointe, Mich. Application July 25, 1947, Serial N 0. 763,531

3 Claims. 1 This invention relates broadly to transfer apparatus and moreparticularly to apparatus of this character which is adapted to transfer workpieces progressively through a series of work stations. vAn important object of the present invention is to provide an apparatus which will pick up a workpiece from one work station, transfer itlaterally to an adjacent station, deposit it, and then return to the first station.

Another object of the invention isto providean apparatus of the above-mentioned character which can be easily adapted to handle many types of work. J Still another object of the invention is to provide an apparatus of the above-mentioned character having means for automatically positioning workpieces properly with respectto a work station adjacent thereto.

Yet another object of the invention is to provide an apparatus of the above-mentioned character which is automatic in operation.

, A further object of the invention is to pro- .vide an apparatus of the above-mentioned character which can be readily ontrolled. by mechanism in the work station to cycle automatically .as soon as the operation to be performed in that .particular station is completed. r A still further object of the invention is to' provide an apparatus of the above-mentioned character having means for positioning theworkpiece during that portion of the cycle when it is transferred from one work station to another.

A yet further-object of the invention is, to pro vide an apparatus of the above-mentioned character which is simple but rugged in construction and relatively inexpensive to manufacture.

Other objects and advantages of the invention will be apparent during the course of the following description. I

In the drawings forming a part of this specification and wherein like numerals are employed 'to designate like part throughout the same:

' Fig. 1 is a top plan view of a. transfer apparatus embodying one form of the invention;

Fig. 2 is a vertical sectional view taken on the line 2-2 of Fig. l;

a Fig. 3 is a fragmentary, vertical sectional view taken on the line;33 of Fig. 2;

Fig. 4 is a fragmentary, vertical sectional view *taken on the line- 4-4 of Fig. 2; Y a Fig. 5 is a fragmentary, vertical sectional view taken on the line 5-5 of Fig. 1; i Fig. 6 is a fragmentary, vertical sectional view -taken on the line 66 of Fig. 1; v H

10A; and

spect to Fig. 7 is a schematic view of the control system for the transfer apparatus;

Fig. 8 is a partial View showing the positioning of certain of the limit switches and the actuators therefor; v

Fig. 9 is a partial view showing the positioning of certain other of the limit switches and the actuators therefor;

Figs. 10A and 10B illustrate leftand righthand portions respectively of a modified transfer apparatus embodying the invention;

Fig. 11 is an enlarged, fragmentary, vertical sectional View taken on the line II--Il of Fig. 10A;

Fig. 12 is an enlarged, fragmentary, vertical sectional view taken-onthe line I 2l 2 of Fig. 11; Fig. 13 is an enlarged, vertical sectional view taken on the line [3 -13 of Fig. 10A;

Fig. 14 is an enlarged, vertical sectional view taken on the line |4I4 of Fig. 10A;

Fig. 15 is an enlarged, fragmentary, horizontal sectional view taken on the line l5l5 of Fig. 10A; v

Fig. 16 is a fragmentary, vertical sectional view taken on the line Iii-l6 of Fig 15;

Fig. 17 is averti'cal, transverse sectional View taken on the line ll-ll of Fig.10A;

Fig. 18 is a vertical, longitudinal sectional view taken on the line l8-l8 of Fig. 17;

Fig. 19 is anenlarged, fragmentary, vertical sectional view taken on'the line l9l9 of Fig.

Fig. 20 is a schematic view of the control system for the modified transfer apparatus. -35

theinvention comprises an apparatus for moving workpieces q automatically from Considered in certain of its broader aspects,

v a one work station to another and progressively through a series of workstations. The work stations must be uniformly spaced and usually are occupied by machines which perform some operation on the work; however, ;the stations'may merely contain supports which hold idle workpieces between machining operations or they may contain apparatus for positioning the work properly with rea machine in the next succeeding station. v

= In general, the apparatus comprises stationary worksupports in each work station, transfer dev ces having a horizontally movable slide equipped with workfholding members, and hoists for raising and lowering the slide to move the work-holdingmem-bers between positions above and below the stationary work supports." Means is provided for shifting the slide horizontally and 3 for properly-controlling the movements both of the slide and of the hoists. By properly coordinating the movements of the various mechanisms, the apparatus can be made to cycle automatically either continuously or intermittently under the control of a manual starter switch.

At the beginning of a cycle, the apparatus is positioned with the hoists lowered, the slide retracted, and the work-holding members positioned to engage workpieces on the stationary work supports. In operation, the slide is first raised by the hoists to lift the work-holding members from a position below to a position above the stationary work supports so that the members pick up workpieces from the supports. The slide is then moved horizontally in the manner hereinabove described to transfer the workpieces to adjacent work stations, and the hoists are then lowered to deposit the workpieces on the stationary supports in the last-mentioned stations. To complete the cycle of operation, the slide is returned either with the hoist in lowered position or the motions hereinabove described are reversed with the work-holding members positioned to release or disengage the work- 1 pieces depending upon exigencies of the particular situation. The above steps are performed simultaneously in all of the work stations, and after each cycle of operation, an unfinished workpiece is placed either manually or by suitable mechanical means on the first station at one end of the apparatus, and a finished workpiece is removed from the last station at the opposite end thereof.

The apparatus shown in Figs. l-9 was designed primarily for transferring pipe or the like; however, it is not intended that the apparatus be limited to this use, as it may be employed in any capacity where an apparatus Of this character has utility. In the apparatus here shown by way of illustration only four work stations designated generally by the numerals 20, 22, 24, and 26 are shown, but it will be readily apparent that the apparatus can be easily adapted to operate with any desired number of stations. Also, it will be observed that in the illustration all four stations are at one side of the transfer device. This arrangement, however, is not essential, since if desired, certain of the work stations may be at one side of the transfer device and other work stations at the other side thereof.

Work stations 22 and 26 are occupied by maehines'for performing certain operations on the workpieces, work station contains apparatus for positioning the work'properly withrespect to the machines in station 22, and work station 24 is merely an intermediate idle station in which no operations are performed on the work. The specific construction and operation of machines in stations 22 and 26 are conventional and comprise no part of -the present invention. They are shown merely by way of illustration, and since they are incidental to the invention a detailed description thereof is not necessary.

The apparatus here shown is adapted to transfor two workpieces side by side simultaneously through work stations 20, 22, 24, and 26. In this connection, however, it will be readily apparent that the apparatus can be readily adapted to handle a single workpiece in each work station or to handle three or more workpieces simultaneously in each work station. V

The first work station 20 comprises a series of rollers 28 which support the workpieces (not :shown) and a vertical stop 30 at one 'end or the rollers 28. In operation, the stop 30 abuts one end of the workpieces and positions the latter properly with respect to the machines in adjacent work station 22. As best shown in Fig. 1, the rollers 23 are arranged in pairs and the two rollers in each pair are fixed on a shaft 32, which shaft is supported at its ends by standards 34 (Fig. 5) and is continuously driven by a motor 36 through gears 38 and 40 and an endless chain 42. Corresponding rollers 28 in each pair are disposed in alignment with each other, so that a pipe or other workpiece of elongated structure can be laid thereon and collectively supported thereby.

Thus, in the work station 20 here shown, two pipes are placed side by side on the two series of rollers 28, and motors 36 continuously rotate these rollers in a direction to move the workpieces axially against the stop 30. The workpieces may be loaded on the rollers 28 either manually or mechanically by apparatus well known in the art, and, in practice, they preferably are placed on the rollers in approximately the desired position with respect to the stop 30. Thus, the axial travel imparted to the workpieces by the rollers 28 is relatively short, and as a consequence, the rollers can be rotated relatively slowly. The rollers continue to rotate after the workpieces have moved against stop 30 and hold the workpieces so positioned until they are picked up by the transfer device.

The apparatus for transferring the workpieces from one work station to another comprises stationary Work holders 44 and transfer devices 46 arranged alternately in laterally spaced relation at one side of the rollers 28 and extending across the entire series of work stations 20, 22, 24, and 2'5. In'the embodiment of the invention here shown, three stationary work holders l4 are provided between four transfer devices 46. In this connection, however, it will be readily understood that the number of work holders 44 or transfer devices 46 is not critical and that any number of these units required to handle a particular workpiece can b provided. Also, in many instances it may not be necessary to provide a stationary work holder 44 between each pair of transfer devices 46. For example, if the workpieces are uniformly long and rigid, two work holders at opposite ends of the apparatus may be sufiicient. On the other hand, if some of the workpieces are relatively short or are flexible in character, it may be necessary to provide more than'one stationary work holder'44 between each pair of adjacent transfer devices 46.

For a specific description of the stationary work supports 44 reference is had to Fig. 6. All of the supports 44 are identical in construction, and a detailed description of one therefore will suffice.

Each support 44 comprises a horizontal beam 58 which is supported at spaced intervals by upright standards 50 and carries a plurality of uniformly spaced upstanding V-blocks 52. All of the supports 44 are of uniform height and the height is determined by the character of the machines in stations 22 and 2B. In practice, the workpieces rest on the V-blocks 52 and these blocks should position the workpieces for proper engagement by the machines. Since the workpieces are supported by rollers 28 in work station 20, the supports 44 extend only across work stations 22, 24, and 26. Two V-blocks 52 are provided on each beam "48 for each of the work stations '22, 24, and 26, and the V-blo'cks are spaced uniformly with respect to each other and with respect to the rollers 28.

For a detailed description of the transfer devices 46 reference is had to Figs. 2, 3, and 4. .All of the transfer devices 46 are identical in constructionan-d operation, and'a detailed description of one therefore is sufiicient.

Each transfer device 46 comprises a slide 54 mounted for horizontal translatory movement on a supporting beam 56. The beam 56, in turn, is carried by and supported on two hoists 58 located adjacent opposite ends thereof. Slide 54 carries a row of V blocks 68 which are uniformly spaced on the same centers as V-blocks 52, and provision is made for driving these slides back and forth onv the beam'56 a distance equal to the distance be- .tween adjacent work stations 20, 22, 24, and 26.

At one end of its horizontal travel, slide 54 is positioned with the two endmost V-blocks 60 in alignment with respective rows of rollers 28, and at the other limit of its travel, the two V-blocks 50 referred to above are positioned in alignment with th two endmost v-blo-cks 52 on thestationary work holders 44. Hoists 58 raise and lower the slide assembly to move the V-blocks 66 between positions above and below the V-blocks 52.

At the beginning of a cycle of operation, slide 54 is retracted a maximum distance to the left as shown in Fig. 2 so that the two endmost V- blocks 62 are aligned with. the two series of rollers 28 -(Flg. l), and the hoists 58 are lowered to position V-blocks 56 below rollers 28 and also below the V-blocks 52. Two workpieces are then placed on respective rollers 28 and are immediately 48 from whi-clrzthey' are removed either manually or by suitablemechanical means before the transfer device completes anothercycle of operation.

scription of the same reference is had to Figs.

2-4. The slide 54 is shown in the form of an I-beam (Figs. 3 and 4), and the V-blocks 60 are welded or otherwise fastened permanently on. the upper flange thereof. The support 56 comprises a pair. of channels 62 arranged in parallel,

- spaced relation below the slide 54 and fastened shifted longitudinally by the latter against the 1 stop 35, which stop positions them for proper engagement with the machine in work station 22.

As soon as the workpieces engage stop 38, the transfer device operated to transfer them to work station 22. As the transfer device begins its cycle of operation, the hoists 38 raise the slide 54 and its supporting beam 56 sufiiciently to move .V-blocks 60 to a position above rollers 28. As V- blocks 68 rise to a position above the rollers 28, they pick up the workpieces and lift them sufficiently to clear the rollers. When hoists 58 reach the upper limit of their travel, the slides 54 are moved simultaneously to the right, as viewed in Fig. 2, to position the workpieces directly above the first two V-blo-cks 52 and in alignment with respective machines in work station 22. Hoists 58 are'then moved downwardly a distance sufiicient to position V-blocks 65 below V-blocks 52. Manifestly, when V-blocks 60 move below the V-blocks 52, workpieces carried thereby are deposited on the stationary work supports 48 and are entirely released by V-blocks 60. As soon as hoists 58 reach the lower limit of their travel, slides 54 traverse to the left as viewed in Fig. 2 to their initial or starting position. As suggested, two workpieces are then placed on the rollers 28 preparatory to another cycle of operation by the transfer device, while the two workpieces which were transferred to work station 22 are acted upon by the machines in the latter station.

From the foregoing, it will be readily apparent that each operation of the transfer devices 46 moves workpieces from any or all of work stations 20, 22, 24,.and 26 to the next succeeding work station. The workpieces are moved in groups of two and all of the workpieces are moved simultaneously. Those workpieces removed from the endmost work station 26 are deposited on the two endmost: V-blocks 52 of stationary supports solidly together by. a'transverse bar64. Rollers 66 carriedby and located at opposite sidesof the I-beam 54 travel on wear plates 68 welded or otherwise fastened on the upper flanges of channels 62. Wear plates 68 may extend the full length of the supporting channel 62 or they may extend only for a short distance corresponding to.

as shown in the d'raw- I the travel of the I-beam ings.

Hoists 58 are provided at opposite ends of the transfer device as perhaps best shown in Fig. 2,

and since the hoists are identical, a detailed de scription of but one is given. Each hoist comprises a housing 10 having base flanges 12 which are anchored solidly to the floor or other suitable support by bolts 14 or the like. A pair of laterally spaced racks 16 are mounted for vertical sliding movement in the housing 70, and the upper ends of the racks extend above the housing and are fastened to respective channels 62 by suitable mountings 78. The two racks 16 are raised and lowered simultaneously by pinions on a shaft 82 which extends transversely through and is journaled for rotation in the housing 10. Intermediate the: two pinions 80 is a driving pinion 84; and a horizontal rack 86, mounted for sliding movement in the housing 10, meshes with the pinion 84 to rotatably drive the same. In order to relieve the various racks and pinions of excessive strain, a counterweight 88 is provided for each of the vertical racks 76. In the form of the invention here shown, the counterweights 88 are disposed in suitable guides'90 on one vertical wall of the housing 18 and are connected to their respective racks 16 by flexible ca-- bles 92, which cables pass through openings 94 in the upper portion of the wall and over pulleys 96 which are journaled for rotation in the openlugs 94.

As best shown in Fig. 2, the two horizontal racks-86 of hoists 58 are connected for simultaneous operation by a connecting rod 98 so that all four of the vertical racks l6 operate in unison.

Provision also is made for co-ordinating the slides and hoists of the several transfer devices 46. To this end, a rack I08 is fastened to the bottom flanges of each I-beam slide 54, and these racks mesh with pinions l02'carried by a common shaft I04 which connects the transfer devices 46and is journaled for rotation in suitable bearings I06 in channel supports 62 (Fig. 3). Thus if any slide 54 is actuated, motion is transferred to the other slides in the assembly through the shaft I04. Asv a result, all of the slides 54- are positively connected for simultaneous operation. Similarly, the horizontal shafts 82 of hoists 58 are connected by suitable couplings I08 so that movement imparted to any hoist automatically is transferred to the other hoists in the assembly. f V

. According to the present invention, drivingmeans is provided only for the two middle transfer devices 46 and the two outer transfer devices are driven through the coordinating mechanisms hereinabove described. Both the slides 54 and the two hoists 58 are operated pneumatically.

To this end, each of the middle'transfer devices 46 is provided with a pneumatic cylinder and piston assembly, designated generally by the numeral IIO, which is mounted between channels 62 with the piston acting against the transverse connecting member 64 (Figs. 2 and 3). Also, each of the middle transfer devices 46 is equipped with a second pneumatic cylinder and piston assembly, designated generally by the numeral H2, which is mounted on a suitable support H4 beside one of the hoists 58 with the piston connected to the adjacent rack 86 (Fig. 2). The piston and cylinder assemblies of fluid motors III] and II2 are respectively controlled by three-way valves H6 and H8 operated by solenoids I20 and I22 under control of limit switches LSI, LS2, LS3, LS4 and LS5. The switches LSI, LS3 and LS4 are of the normally open type closed by their respective actuators while the switches LS2 and LS5 are of the normally closed type opened by their actuators. Switches LSI and LS2 are carried by one of the housings I and are actuated upon movement of the racks 86 to their left-hand limit of movement, while switch LS3 also carried by one of the housings I0 is actuated upon movement of the racks 86 to their right-hand limit of movement. Similarly, switches LS4 and LS are carried by the support 56 and actuated at the left-hand and righthand limits of movement of the slide 54.

More specifically, a pair of busses I24 and I26 energized from a suitable source of electrical energy upon closure of the line switches I28 supply the control energy for the operating relays and solenoids. A conductor I3Il having limit switches LSI and LS4, and a manually closed start switch SW, connects one terminal of the energizing coil of a relay RI to the buss I24. The other terminal of this winding is connected through a limit switch LS5 to the other buss I26 by a conductor I32. A conductor I34 connects the buss I24 through normally open contacts a of the relay RI to the same terminal of the energizing winding as does the conductor I38 in by-pass arrangement to provide a locking circuit therefor so that once the relay BI is energized it will remain in that condition until opening of the switch LS5. One terminal of the energizing winding of the solenoid I22 is connectedto the buss I24 by conductor l38'while its other terminal is connected by a conductor I38 having normally open contacts I) of the relay RI to the buss I26. A conductor I48 having the limit switch LS8 connects one terminal of the'energizing winding of a relay R2 to the buss I24, while a conductor I42 connects the other terminal of this energizing windingto the buss I26. A con-' ductor I44 having the limit switch LS2 connects the buss I24 through normally open contacts a of the relay R2 to the same terminal of the energizing winding as does the conductor I40 in bypass arrangement to the switch LS3. A conductor I46 connects the buss I24 to the normally open contactsb of relay R2 to one terminalof the energizing winding of the solenoid I20; hav ing' its other terminal connected by conductor I48 to the buss I26.

The remainder of the details of the control circuit may best be described by a description of its operation. With the racks 86 in their left-hand position and, consequently, the support 56 lowered and with the slide 54 at its left-hand position with rsepect to the support 56, the switches LSI, LS4 and LS5 will be closed and the switches LS2 and LS3 will be opened as shown in Fig. '7. Assuming that the line switches I28 are in closed circuit position so that the busses I24 and I26 are energized, closure of the switch SWI will energize the relay RI through the closed switches LSI, LS4 and LS5. Closure of the contacts a of relay RI establishes a holding circuit for the relay RI in by-pass arrangement to the switches SW, LSI and LS4 which can now be opened without interrupting the cycle of operation about to be described. Closure of the contacts b of the relay RI establishes a circuit from the buss I24 through conductor I36, the energizing winding of the solenoid I22 and the conductor I38 to the buss I26. Energization of the solenoid I22 moves the valve II8 downward thereby admitting fluid pressure to the left-hand pressure chamber of the fluid motor I I2 whereby the piston I50 thereof is moved to the right causing the racks 86 to rotate the pinions 80 and 84 and drive the rack I6 in an upward direction raising the slide 54 and support 56 to cause the V-blocks 60 to lift the work from the V-blocks 52. Initial movement of the racks 86 and the connecting rod 98 in a direction toward the right acts to open the limit switch LSI without effect since the by-pass circuit through the conductor I34 and the contacts a of the relay RI is now closed and to close the switch LS2 without efiect since the contacts a of the relay R2 are now open. As the slide 54 reaches its uppermost position due to the racks 86 reaching their rightmost position, the limit switch LS3 is closed thereby energizing the relay R2 through an obvious circuit and closing contacts a and b of this relay. Closure of contacts a completes a holding circuit through the conductor I44 for the energizing winding of the relay R2 since the limit switch LS3 is now closed. Closure of the contacts I) of the relay R2 completes an obvious energizing circuit for the solenoid I20 whereby the valve H6 is moved downwardly to supply fluid pressure through the left-hand chamber of the fluid motor I I0 so that the piston thereof will move toward the right moving the slide 54 relative to the support 56 in a right-hand direction, whereby the respective V-blocks 60 and the work supported thereby are transferred from one station to the next station. Upon initial movement of the slide 54 to the right, limit switch LS4 is opened without efiect since the relay BI is energized through the by-pass conductor I34, Upon completion of the stroke of the slide 54 to the right, the limit switch LS5 is opened thereby deenergizing the relay RI permitting the contacts a and b thereof to open. The opening of the contacts a of the relay RI is without effect since the circuit therethrough was broken upon opening of the limit switch LS5. Opening of the contacts b de-energizes the solenoid I22 so that the valve II8 may be moved upwardly by the spring I50 permitting fluid pressure to be applied to the right-hand pressure chamber of the fluid motor H2 and to permit the fluid to exhaust from the left-hand chamber thereof.

- The racks 86 now move in a left-hand direction by the V-blocks 60 to be received by the work supporting V-blocks 52. Initial movement of the racks 86 in a leftward direction opens the limit switch LS3 which opening is without effect since a by-pass circuit therearound is made through the now closed limit switch LS2 and the contacts a of the relay R2. Upon completion of the leftward travel of the racks 86 and consequent downward movement of the slide 54 and its support 56, the limit switchLSI is closed without effect since the. switches LS4 and LS5 are now open. The switch LS2 is opened thereby de-energizing the relay R2 causing its contacts a and b to open. Opening of the contacts b de-energizes the solenoid I20 permitting the spring I52 to actuate the valve II6 back to the position shownwhereby fluid pressure is supplied to the right-hand-pressure chamber of the fluid actuator III) and the left-hand chamber is open to exhaust. 'The slide 54 now moves leftwardly with respect .to the sup- .56 and the slide 54 permitting the work carried Two V-blocks, I 64 should be provided in each station but these blocks may be spaced various distances apart. For example, in the idle stations I54, I58, and I62 the V-blocks I64 are positioned to engage the axle housing immediately behind the end flanges thereof; whereas, the V-blocks in work stations I56 and I66 are positioned to engage the axle housing at the. outer sides of the flanges;

stations I56 and I60-the V-blocks are mounted on supporting arms I10 which are fastened on the machines in such stations. In this connection, however, it will be readily apparent port 56 bringing the slide 54 back to its-original position. In its initial movement of the slide 54 toward its original position, the switch LS5 closes without eifect since switchLS4 is still open. Upon completion of the movement to the original position, switch LS4 is closed and if the'manually operated switch SWI is still closed another cycle exactly the same as the one just described will be initiated whereby additional workpieces are transferred from one station to the next station.

Theapparatus shown in Figs. 10-20 is adapted primarily for transferring axle housings of automotive vehicles progressively and automatically through a series of work stations designated generally by the numerals I54, I56, I58, I60, and I62. In the form of the invention here shown, alternate stations I54, I58, and I62 are idle stations and the remaining stations I56 and I66 are occupied by machines which perform some operation 6 on the workpiece.

The machines here shown in stations I56 and I60 are conventional and comprise no part of the present invention.

In this connection, however, it will be readily apparent that the sequential relationship of the work stations is not critical; viz;, the machines need not be arranged alternately with respect to the idle stations. If desired, two or more machines may occupy adjacent positions or two or more idle stations may be disposed between adjacent machines, depending upon the exigencies of the particular situation. Also, although five work stations" are here shown,v it will be readily apparent that the apparatus can be adapted to a greater or lesser number of stations. In each instance, the number of stations that, if'desired, aseparate supporting structure may be provided for the V-blocks' I66 in those stations occupied by machines.

In this form of the invention, the transfer device is mounted above and extends the full length of work stations I54I62. A suitable 1 supporting framework'for the device is .provided,

will vary, depending upon the character ofthe I work being handled and the nature of the oper 'ations to be performed thereon. It is essential that the work stations be arranged in alignment and that they be spaced equal distances apart; however, it is contemplated that several apparatuses of the type here shown maybe used side by-side and in conjunction with means for transferring the workpieces from one apparatus to another if a large number of operations are to be performed on the workpiece. I

Each work station is equipped with suitable stationaryworksupports upon which the workpiece rests, and the work supports in the various stations are all arranged at a uniform height.

.In the apparatus here shown, the work supports .comprise spaced V-blocks I64 which engage the .axle housing workpiece I66 adjacent its ends.

and this framework is here shown in the form of-a plurality of inverted 'U-shaped supports I12 which straddle the line of work stations and are disposed substantially equidistantly therealong. Welded or otherwise fastened'substantially centrally to the crosspieces of supports I12 is a longitudinal stringer -I14. This framework can be fabricated'from structural members of any suitable size or shape and the elements thereof are ,welded, bolted, or otherwise fastened solidly together toprovide an essentially-rigid structure. In the form of the in-v vention here shown, the supports I12 are made of I beams, and the stringer I14 comprises-a pair of channelsarranged backto back in spaced parallel relation.

The transfer device itself is suspended from the supporting structure hereinabove described and comprises a longitudinal slide support I16 which extends across all five work stations and is suspended from the stringer I14 by a plurality of hoists I18. Carried by and depending from the slide support I16 is a slide member I which extends longitudinally of the apparatus across four of the five work stations and is equipped with a pair of work-holding members I82 for each of the four work stations. It will be observed that the slide I 86 is adapted to travel horizontally with respect to the slide support I16 on a series of rollers I64 and that the workholding members I82 in each pair are positioned to engage opposite ends ofthe-workpieoe I66. Also, it will be observed that the work-holding .members I82 are pivotally mounted on the slide I86 and that they are movable on their pivots is raised and lowered by the hoists I18. When the transfer mechanism is fully lowered, the portions of work-holding members I82 which engage the workpiece I 66 are positioned below the terminal portions of the workpieces, and when the transfer mechanism is raised with the work-holding members closed, the workpieces are raised simultaneously from the stationary'work supports I64. Suitable mechanism is provided for operating and co-ordinating hoists I18 so that they raise and lower the slide support I16 and its appurtenances a distance sufficient to move the work-holding members I82 from a position below the terminal portions of the workpieces I66 to a position where the workpieces I66 carried by work-holding members clear the stationary work supports I64. Manifestly, if the hoists I18 are raised with the work-holding members I82 closed, the workpieces I66 are raised from the stationary work supports I64 and transposed to another station when slide I80 is moved horizontally; whereas, if the hoists are raised with the work-holding members open, the workpieces remain on stationary supports I64 and the transfer device is raised sufficiently to clear the workpiece when the slide I80 is moved horizontally. Mechanism also is provided for translating the slide I80 a distance equal to the distance between adjacent work stations, which mechanism is operable only when hoists I18 are raised but with the workholding members I82 either opened or closed.

Initially, hoists I18 are in lowered position with the slide I80 in retracted position above the first four work stations I54, I56, I58, and I60 and with the work-holding members I82 open. In a typical cycle of operation all of the work-holding members I82 are first closed simultaneously to engage all four workpieces I66 in stations I54, I56, I58 and I60, and hoists I18 are then raised to lift the workpieces simultaneously from the above stations. When the hoists I18 are fully raised, slide I80 is actuated to move all of the workpieces I66 one station to the right. as viewed in the drawing (Figs. A and 10B). Hoists I18 are then lowered to deposit workpieces I66 inthe adjacent stations I56, I58, I60, and I62 respectively, and the work-holding members I82 are opened to disengage the workpieces. Hoists I18 are then raised, slide I80 retracted to its initial position, and the hoists lowered with the work-holding members I82 open to complete the cycle of operation.

Control mechanism may be provided for performing the series of operations described above automatically either continuously or periodically at fixed intervals, or, alternatively, the control mechanism may be made to operate only under the control of a manual starter switch and to perform the series of operations automatically only when the starter switch is operated.

After each cycle of operation, a new workpiece is placed either manually or automatically on the stationary work supports I64 of work station I54, and a workpiece is removed either manually or automatically from the work supports of station I62.

Each of the hoists I18 is identical in construction and operation, and a detailed description of one therefore will suflice. For this description reference is had to Figs. 11 and 12 wherein the numeral I86 designates a housing for a rack I88 and a pinion I90. The housing I86 is arranged below the stringer channels I14 and is fastened solidly thereto by bolts I92. Within the housing I86 and disposed substantially midway between the channels I14 is a vertical bore I94 which receives the rack I88, and sleeve bearings I86 are provided in opposite ends of the bore to slidably support the rack. Rack I88 extends entirely through the housing I86, and a cap I98 is fastened to the upper end thereof to limit downward movement of the rack. On the projecting lower end of rack I88 are brackets 200, which brackets are fastened to the slide carrier I16 by bolts 202 or 'gether by cross plates 234.

the like. A plate 284 interposed between brackets 200 and slide carrier I16 hold the two channels which make up the carrier in fixed spaced relation. The pinion I90 is keyed on a stub shaft 206 which is rotatably supported in the housing I86 by roller bearings 208. Packing glands 2 I0 around the projecting terminal portions of stub shaft 62 and fastened to housing I86 by bolts 2I'2 retain the bearings 208 and prevent lubricant in the housing from escaping along the shaft. As best shown in Fig. 11, the pinion I90 is disposed in a chamber 2 I4 which opens exteriorly of the housing and communicates at right angles with bore I84. The pinion is inserted in housing I86 through the open outer end of chamber 2 I4, and 2h: latter is normally closed by a removable plate 'In operation, the pinion I90 is rotatably driven to raise or lower the rack I88. It will be readily apparent that actuation of the rack raises or lowers the slide carrier I16 and its appurtenances.

In order to co-ordinate the hoists I18, connecting rods 2I8 are inserted between the pinion shafts 206 of the various hoists and connected thereto by suitable couplings 2 I 8. Thus, rotation of the shafting 206, 2I8 operates the hoists I18 in unison.

In the form of the invention here shown by way of illustration, hoists I18 are operated by means of a fluid motor 220 which is mounted on the stringer I14 at substantially the middle thereof. Fluid motor 220 comprises the usual cylinder 222 and a piston (not shown) having the usual piston rod 224. The latter extends downwardly from the cylinder and carries a rack 226 which meshes with a pinion 228. Both the rack 226 and pinion 228 are mounted in a suitable housing 230 which is generally similar to the housings I86 hereinabove described. The housing 238 is disposed below and bolted to the stringer I14 in alignment with the fluid motor 220 (Fig. 19). Pinion 228 is keyed or otherwise fixed on a shaft 232 which is coupled in the shafting which operates the hoists I18 (Fig. 10A).

Manifestly, when the fluid motor 220 is operated to move piston rod 224 and rack 226 downwardly, pinion 228 drives the shafting 206, MB, and 232 in a clockwise direction, as viewed in Fig. 19, to raise hoists I18 and the work transfor device carried thereby. Alternatively, operation of the fluid motor 220 to raise piston rod 224 and rack 226 rotates the pinion 228 and the shafting associated therewith in a counterclockwise direction, as viewed in Fig. 19, to lower the hoists I18 and the work-transfer device carried by the hoists.

. The slide I 88 comprises a pair of channels arranged back to back and in spaced parallel relation as shown in Fig. 14 and held rigidly to- As suggested, the slide I extends over four of the five work stations and is movable from a position above stations I54, I56, I58, and I60 to a position above stations I56, I58, I60, and I62. Cross plates 234 are provided with upstanding arms 236 (Fig. 10A) which carry the rollers I84. As suggested, sets of rollers are provided at longitudinally spaced intervals along the slide; and there are two rollers in each set, which rollers ride on the lower flanges of respective slide-supporting channels I16.

Slide I80 is actuated by a fluid motor 238 (Fig. 18) which comprises the usual cylinder 240 and a piston (not shown) having a piston rod 242.

On the distal end of the piston rod 242 is a rack 244 which operates in suitable guides 246 and aotuates a second rack 248 through the medium of a small gear 258 disposed between the two racks. As clearly shown in the drawing, the fluid motor 238 and rack 244 are mounted between and carried by the two carrier channels I16, and the rack 248 is fixed to the slide I88.

When piston 242 is advanced, rack 244 is moved to the right, as viewed in Fig. 18, and pinion 258 is rotated in a clockwise direction to move rack 248 to the left. Manifestly, slide I88 will move with the rack 248. Conversely,retraction of the piston rod 242 moves rack 244 to the left,

as viewed in the drawing, and rotates the pinion 258 in a-counterclockwise direction to move rack 248 and its appurtenances to the right. As suggested, the stroke of piston 242 is sufficient to move the slide I88 a distance equal to the distance between adjacent work stations.

With reference to the work-holding, members I 82, it will be observed (Fig. 15) that. the two supporting channels I88 are held in fixed relation by spacers 252 and that the channels are bolted or otherwise held solidly together. A pair of work-holding members. I82 is provided for each'work station covered by the. slide I88, and

each work-holding member is pivoted to a supporting bracket 254 which in turn is weldedor otherwise secured to the slide I 88. As best shown in Fig. 16, members I82 are arranged vertically on horizontal pivots and the lower ends'thereof carry blocks 256 which project laterally to support a terminal of the workpiece I66, An actuator linkage connects the upper ends of each pair of work-holding members and means is provided for operating the linkage to open and close the members in the manner hereinabove described,

viz., to movethe work-holding members between the fulland broken-line positions in .Fig. 16.

Specifically, each linkage comprises a relatively short lever 258 which is disposed between the two channels I88 and substantially,midwayv between the two work-actuating, members 182. Lever 258 is keyed or otherwise fixed on a shaft 268 which is journaled in a mounting attached to one of the channels I 88. The ends of lever 258 are connected to respective work-holding members I82 by links 264, and each link is connected to its respective work-holding'member by a lostmotion connection designated generally by the numeral 286,

When the shaft 268 is rotated to position lever 256 substantially horizontally, as shown by broken lines'inFig. 16, the links 264 close the 11.4 work-holding members by a pneumatic actuator means. For this purpose a fluid motor 268 is bolted to a mounting plate 218 at one end of the slide I88 with'the piston rod 212 disposed behind andparallel to the channel which carries the stub shafts 268. Preferably the mounting plate 218 extends beyond the motor 268, and the projecting portion thereof forms one of the spacers 252 as shown in Fig. 15. Each of the stub shafts 268 is provided with a pinion 214 and aligned racks 216 mesh with these pinions. a guide assembly 218 which is welded on-the. adjacent channel I88, and the racks are con nected to each other and to the piston rod 212 by suitableconneeting rods 288.

From the foregoing it will be readily apparent that, when piston 212 is retracted, racks 216 are moved simultaneously to the left-hand limits of theirtravel and stub shafts 268'are rotated in a clockwise direction, as viewed in Fig. 16, to close the work-holding members 282. Conversely, ad vancement of piston 2'12 moves the racks 218 in unison to the right as viewed in Fig. 15 and rotates'the stub shafts 268 in a counterclockwise direction to open the work-holding members I82. Since all of the racks 216 operate in unison, all of the pairs of work-holding members operate synchronously.

In the'form of the invention here shown, each work-piece I 66 is supported middle by a holding pad 282 which is suspended from and bolted to'a mountingblock 284 on the slide I881 The mounting bolts 286 which hold pad 282 on the block 284 permit limited movement of'the-pad relative to'the mounting plate, and spring means 288 interposed between the mounting and pad urge the latter downwardly against the workpiece I66. By reason of the springpressed engagement between pad 282 and work piece I66 the latter is held in a selected rotatably adjusted position in the work holders I82.

The control system for the modifiedform of transfer apparatus shown in Figs. 18 through 20 comprises three-way valves-288, 296, and 382 for controlling the flow of pressure fluid to the fluid motors 268,228, and 238 respectively. Each of the valves is operated by a pair of solenoids 292-294, 298-388, and 384'386 respectively. The

valves

298, 286, and 382 are each of the type in which the energization of one of its controllingv solenoids will actuate the valve into-the respective controllingposition after which the valve will reholding members I82. Conversely, when shaft 268 is rotated tomove the lever 256 to the position shown by full lines in Fig. 16, links 264 pull the attached ends of work-holding members I82 toward each other and rock such members about their pivots to the fullor open-line position. In the latter position, work-holding members I82 release the workpiece I 66.

It may thus be seen that both work-holding members I82 in each pair are operated in synchronism and that they are opened or closed simultaneously. Also, by reason of-the instant arrangement, the actuator linkage is positioned between and protected by the spaced slide channels I88. In this connection, it will be readily .apparent that the strong rigid slide provides an excellent support for' the work holderspand the actuator mechanism and that the entire structure is compact and exceedingly strong. 7

According to the present invention, the pairs of main in that position irrespective of the con- .tinued 'energization thereof until such time as the other of its controlling solenoids is energized. The energization: of the various solenoids is controlled by a series of normally open limit switches are actuated to closed position at the end limits of travel of the'various movable members.

Limit switches LS-? and LS-8 are actuated re spectively when thework-holding members are in a releasedand a work-holding position and are with the fluid motor 258. Limitswitches LS4! andLS-i8 carried by the slide'support I16 are actuated respectively upon movement of the slidelail to its left-hand and its right-hand positions by abutments 388 and 3 I8 carried. by the rack 244. Limit switches LS-II and'LS-IZ, carried by the housing I88 of the hoist I18, are engaged by an abutment 3H2 carried by the. rack I 88 for actuation thereof upon'downward' and upward movement respectively of the work-carrying slide I88. The limit I82 are operated together Each rack 216 is slidably mounted in I substantially at its switch LS-l2 is of the double-circuit-controllins type having two independent sets ofnorrnally open contacts LS-l'aa and LEAR), each being arranged to be moved to closed position upon actuation of the limit switch LS-(Z by the abutment 3l2.

A manually operable starting switch SS-! is moved to closed position to start the cycle of operation which comprises actuating the workholding members or hooks Hi2 into work-holding position with respect to the workpiece 55, actuating the hoist 6TB to lift the workpieces E53 upwardly, actuating the slide member 80 to move the workpieces H56 horizontally to the next station, actuating the hoists 118 to lower the workpieces E96, actuating the hooks 82 to move them out of work-holding position with respect to the workpieces I56, actuating the hoists lit to raise the hooks I32, actuating the slide member I86 whereby it is returned to its left-hand position, and actuating the hoists {7-8 to lower the hooks H32 into a position in which they are in a position to be actuated for lifting the next workpiece I65. As each of the foregoing steps is completed, limit switches LS-l' through LS-l2 are actuated, whereby the series of steps is carried on automatically without further efiort on the part of the operator. 1

Power from a suitable source of supply is supplied to the bus conductors 3M and 316 through usual line switches Bit! and 329 respectively. One terminal of the energizing winding of the solenoid 292 is directly connected to the bus 314 while the other terminal is connected through the start switch SS4 and contacts a of a work-cycle control switch WS-l to the bus 3H5. One terminal of the energizing windingof the solenoid 294 is connected directly to the bus 3M while the other terminal is connected through the contacts I) of the switch WS-l and through the contacts a, of the control relay CR-l to the line 316. Likewise, one terminal of each of the energizing coils of the solenoids 298, 399, 304. and 396 is connected to the bus conductor 314. The other terminal of the energizing winding of the solenoid 298 is connected to the bus 318 through two parallelly arranged conductors 322 and 324. The conductor 322 has therein the contacts a of the control relay CR4 and the contacts a of the control relay CR ri. The conductor 324 contains the contacts a of the control'relay Cit-3 and the contacts a of the control relay CR-B. The other terminal of the energizing winding for the solenoid 303 is also connected through two parallelly extending conductors 326 and 328 to the bus conductor 3I6. The conductor 325 contains the normally open contacts b of the control relays CR-3 and CR-B while the conductor 328 contains the normally open contacts b of the control relays CR4 and CR4. The other terminal of the energizing winding for the solenoid 3% is connected through the normally open contacts LS-l2a and the normally open contacts 0 of the control relay CR;-3 to the bus conductor 3H5. Likewise, the other terminal of the energizing winding of the solenoid 395 is connected through the normally open contacts LS-iZb and contacts 0 of the control relay CR-t to the bus conductor SIB. A conductor 339 is interconnected between thebus conductors 3M and 3l6 and has therein-the limit switch LS-ll and the control winding for the control relay CR-l. A conductor 332 isalso connected between the bus conductors 3M and 319 and has therein the limit switch LS-9 and the energizing winding for the control relay CRr-G.

Likewise conductors 334, 336, and 338 are also connected between the bus conductors 3H!- and 316 and have respectively therein the limit switch LS-l t and the energizing winding for the control relay (IR-5, the limit switch LS-i and the energizing winding for the control relay CR-B, and the limit switch LS-S and the energizing winding for the control relay CRPA. It is believed that the remaining details of the electrical circuit for the invention as illustrated in Figs. 10 through 20 may best be understood by description of operation which is ,as follows: 3

Upon closure of the switches SH! and 320 the conductor busses-3l4 and 319 will be energized with electrical potential from a suitable source of supply. Since at the end of each cycle of operation the slide l89'will be lowered and in its lefthand position and the hooks I82 will be open, the limit switches LS-l, 16-9, and LS-! i will be actuated and maintain the relays CIR-3, CR-B, and CR-l energized. Energization of the relays CRF3 and CR-B completes an energizing circuit for the solenoid 398 through the now closed contacts b thereof. The work cycle control switch will normally be in its'shown position with the contacts In closed so that the closure of the contacts a of the relay CRHI will act to energize the solenoid 294, whereby the hooks I82will be maintained out of work-engaging relation. If by any possible chance the hoist H8 should be elevated at the time the line switches 3i8and 320 were closed, the limit switch LS-l2 will be closed; and since the contacts c of the control relay CR-3 are also closed due to the aforesaid energization' of the relay CR-3 the solenoid 386 will be energized to provide the necessary actuation for the fluid motor.233 whereby the hoist H8 is actuated to lowered position closing the limit switch LS-H for energization of relay CRFI.

When it is desired toinitiate a cycle of operation of the transfer apparatus, the work cycle control switch WS-! is moved to its up position whereby contacts a thereof are closed so that when the starting switch S84 is closed, an obvious energizing circuit for the solenoid 292 will be closed, The switch WS-l may be moved to its up position manually or such movement may be the consequence of some other associated function such as the completion of a machining or other work operation at the various stations. It mayfurther be stated that the switch W-S-l is actuated to its shown or down position at some instant after the limitswitch LS-ll has opened 'due to upward movement-of the hoistllB and before the workpiece has been completely lowered into its next position. Again this actuation of the switch WS-l to down position may be as a consequence of the movement of the workpiece or of the transfer apparatus or maybe manual, as desired.

Closure of the starting switch SS-l establishes an obvious circuit for the solenoid 292 through the now closed contacts a of the switch WS-l whereby the valve 299 is moved in an upward direction so that fluid pressure is applied to the fluid motor 238 for moving the connecting rod 212 thereof in a direction toward the left which, as stated hereinbefore, will 'actto close the hooks 132 against the ends of a workpiece I65. Initial movement of the fluid motor 288 to the left will cause the limit switch LS-T-to open, thereby deenergizing the control relay VCR-3 and opening the contacts a, b, and 0 thereof. Opening the contacts a is without effect since the control relay CIR-5 is now tie-energized and the contacts a .thereof are open, breaking the circuit-through the conductor 324. Opening of the contacts b ofthe control relay CR-t de-energizes the solenoid 300, which circuit was previously completed through the conductor 32B and the closed contacts b of the control relay (IR-6 under control of the limit switch LS-S. Opening of the contacts of the control relay CR-3 is without effect since the contacts LS-i2a are already in open position;

As the fluid motor completes its stroke to the left, the limit switch LS-8 will be 'closed, completing an obvious energizing circuit for the control winding of the relay CR- l, causing the contacts a, b, and 0 thereof to be closed. Closure of the contacts a completes an obvious circuit through the conductor 322- for the solenoid 298 since the contacts a of the control relay CR-B .are at this time closed due to the closed 'con- CHI-5 are now open circuited due to the opencircuit condition of the limit switch LS-IO' and due to the open-circuit conditions of the con tacts LS-l2b of the limit switch L842. Y

Initial movement of the hoist H8 in an up.- ward direction opens the limit switch LS4! which de-energizes the energizing winding of the control relay CR-l causing the contacts a thereof to open without eifect since the. contacts I) of the switch WSV-l were already in opencircuit condition as before described, maintaining the solenoid 294 .de-energized. Upon completion of the movement of the hoist in an upward direction, the limit switch LS-l2 will be actuated and the contacts LS-l2a and LS-I2b thereof moved to closed position. Closure of the contacts LS-l2b is without effect, since the contacts 0 of the control relay CR4 are now in open-circuit position. Closure of the contacts LS-lZa, however, completes "an obvious energizing circuit for the solenoid 304 through the now closed contacts 0 of the control relay CR- l. Energization of the solenoid 3,04 moves the control valve 302 in its upward position in which fluid pressure is supplied to the fluid motor 238 to move the piston and piston rod 242 thereof.

Initial movement of the rod 242 in a lefthand direction causes the limit switch LS-9 to open, thereby de-energizing the control relay CR-6 whereby the contacts a and b thereof move to open position. Opening of the contacts a of the relay CRFB de-energizes the solenoid 298 without effect. Opening of the contacts b of the control relay CR-B is without effect,'since the circuit through the conductor 326 is already broken, due to the open-circuit condition of the contacts I) of the relay CR-3. Upon completion of the movement of the piston rod 242 contacts b of the switch to .lower the hoist I18.

the limit switch LS-l.

300 without effect. prepare the valve 296 for operation by the stroke of the fluid ;LS-l' will be closed thereby energizing the energizingthet solenoid 300, since the contacts b of the relay CR4 are now in closed condition due to the closed-circuit position of the limit switch LS-T. Energization of the solenoid 300 'is'fsupplied to the lower side of the piston to move the piston rod 224 in an upward direction Initial'movementof the hoist H8 in a down ward direction opens the switch LS-i2 whereby the contacts LS-lZa and'LSl2b thereof are open. Openingof the contacts LS-l2b is without effect since the contacts CR-3c are already in open-circuit condition. Opening of the contacts LS-lZa. de-energizes the. solenoid 304 since the contacts 03-40 are in closedircuit position due to the closed condition of As stated with respect to the de-energization of the solenoid 298, the

LdeI-e'nergization of the solenoid 304 is without effect upon the valve 302, except as tov place it in condition for operation by the solenoid 306 as will be subsequently described. Upon completion of the downward movement of the hoist I18 the limit switch LS-ll will be closed, thereby re-establishing a circuit through the conductor 330 and re-energizing the control winding of the relay CR-l causing the contacts .d thereof to move to closer position. Since the WS-l are now closed, the closureof the. contacts CR-la will energize the solenoid 29 moving the valve 292 to its lower positionas shown inthe'drawing whereby fluid pressure is. supplied to the fluid motor "268: for movement of the piston 'rod 212 in a tactsa, is without effect, since the circuit through the conductor 322 has already been broken by the open condition of the contacts a of the relay CRJ-G." Opening of the contacts'b of the relay CR- i de-energizes the circuit through the conductor 328 which de-energizes the solenoid However, such action does solenoid 298. Opening of the contacts 0 of the relay CR is without effect, since the contacts LS-l2a are already in open-circuit condition. Upon completion of the right-hand motor 268,'the limit switch control winding of the causing the contacts close.

control relay Cl-t-3 a, b, and 0 thereof to Closure of the contacts a energizes the 'fsolenoid 298 through the now closed circuit of conductor 324, since the contacts a of relay to the left, the limit switch LS-IO will be actu Iated and closed thereby establishing an obvious energizing circuit for the control winding of the .circuit through the conductor 324 is also broken at the contracts a of the control relay CR-3.

Closure of the contacts CR-Sb completes, however, acircuit through the conductor 328 for of the limit switch LS-IO.

grelay gen-3 1 is {condition of thelimit switch LS-H.

(JR-5 are closed due to the closed condition The valve 296 is 'rnov'ed to its upward position whereby fluid pressure is supplied to the fiuid'motor 2?.ilfor moving the rod 224 thereof in a downward direction raising the hoist [.78.

. Closure of the contacts b of the relay CR-3 is without effect, sincethe contacts b of the relay (JR-6 are open,

,due to the open-circuit condition of the limit switchLS-B. Closure of the contacts 0 of the without effect due to the open Initial upwardmovement of the hoist I18 opens the switch LS -l-l whereby the control relay CR-l pressure is supplied to sagas LS-8 is now opened and the contacts c'of the control relay CR-l are now in open-circuit position. Closure of the contacts LS-l2b completes obvious energizing circuit for the solenoid 306,

are now closed due to the closed condition of the limit switch LS-I. E ergizatien of the solenoid 306 moves the valve 302 to its position as shown in the drawings, whereby fluid pressure is supsame as that initially described in which the hoist I18 is down, the slide member I80 is in its left-hand position, and the hooks I82 are in open position. To restart a transfer cycle the switch WS-I is moved to close its contacts a and the start switch SSV-I closed.

It may now be seen that there is provided an automatic system in which closure of the starting switch SS-I will initiate a complete series of operations in which the workpieces are engaged by the hooks I82, are lifted by the hoist I18, are

since the contacts of the control relay 'CR -3 plied to the fluid motor 238 for move ent the piston and rod 242 thereof in a right-hand direc'- tion to cause the slide I80 to move in "a left-hand direction.

Initial movement of the slide 1 B0 in aloft-hand direction or the piston rod 242 in a right-hand direction causes the contacts L's-I0 to open, thereby de-energi'zing the control relay QR-"S. Opening of the contacts aof the relay'CR-o acts to 'de-energize the circuit through the conductor 32! and the now closed contacts a of the relay CR-3 thereby de-energizing the solenoid 208 without effect upon position of the valve 296. Opening of the contacts I) of the relay CR-S is without effect, since the contacts b of the relay CR-l have reviously been opened due to the opening of the limit switch LS-8. Upon completion of the stroke of the slide member I80 to the left or the stroke of piston rod 212 to the right the limit switch LS-9 will be closed thereby completing an obvious energizing circuit for the control relay CR-B whereby the contacts a and 1) thereof will be moved to closed position. Closure of the contacts a is without effect, since the circuit through the conductor 322 is now openby'the open contacts a of the relay CR- -fl due to the open limit switch LS-8. Closure of the contacts b of the relay CR-6 establishes a circuit through the conductor 326 and the now closed contacts I) or the relay CR-3 whereby the solenoid 300 is energized moving the control valve 296 to its lower position as shown in the drawing, whereby fluid V the fluid motor 220 Ifor moving the piston rod 224 thereof in an upward direction and lowering the hoist I18. 7,

Upon initial movement of the hoist I10 in a downward direction, the limit switch LS-I2 will be opened, opening the contacts LS-I; and LS-I2b thereof. Opening of the contacts L's- 12a is without efiect due to the open-circuit condition moved to the right under control of the slide member I80, are lowered by the hoist I18, and are released by the hooks I82 at the next work station. The hoist I78 then raises the work-carrying member, moves it to the left along the slide member I80, and lowers it at the original station with the hook members I82 open ready for reception of a new workpiece.

Having thu described the invention, I claim:

1. A mechanism for transferring workpieces through a series of equispaced stations comprising work-supporting means associated with each of said stations and disposed in substantially aligned equispaced relation, pairs of pivoted work-carrying arms for said stations arranged with the pairs of arms spaced according to the spacing of said work-supporting means, each pair of arms positioned to straddle workpieces on the work-supporting means of a station and movable to engage or release the terminal portions of said workpieces, means for simultaneously actuating said arms between engaged and released positions, an elongated slide common to "and carrying all of said work-carrying arms "mounted to travel in a direction substantially parallel to said series of stations for moving each pair of work-carrying arms back and forth from one station to another, and a hoisting mechanism carrying said slide for moving the latter together with the work-carrying arms associated there- 'with vertically with respect to said work -supporting means.

2. A mechanism for transferring workpieces through a series of equispaced stations comprising work-supporting means associated with each of said stations and disposed in substantially aligned equis'pac'ed relation, pairs of workcarrying arms for said stations arranged with of the contacts 0 of the relay CR-4 under control p or the open-limit switch Ls-a. Opening "of the contacts LS-I2b tie-energizes the circuit 'forthe solenoid 306 through the now closed contacts 0 of the relay CR-3 under control of the "closed limit switch LS4. De-energization of the solenoid '306 is without effect upon the position ofthe control valve 302. 'Upon completion of the'movement of the hoist I18 in a downward direction the switch LS-II is closed, thereby establishing an obvious energizing circuit for'the control relay I CR-I whereby its contacts a are closed without effect since the work-cycle control switch WS I is now in its upward position and the contacts 2: thereof are open circuited. Upon completion of the before-described steps, the apparatus, "will stop and stay in 'thefin'al position which is the the pairs of arms spaced according to-the spacing of said work-supporting means positioned 'to straddle a workpiece on said work-supporting means and provided with V blocks movable under the terminal portions of said workpieces, an elongated slide common to and carrying all of said work-carrying arms mounted to travel in a direction substantially parallel to said series of stations for moving said arms back and forth between adjacent stations, a hoisting mechanism carrying said slide for moving the latter together with the work-supporting means car- 'ried thereby vertically with respect to said worksupp'orting means, and spring-biased pressure pads carried by and movable with said slide en- 'gageable with the workpieces intermediate the ends thereof when the hoisting mechanism is operated to lower the slide, said pressure pads 'being engageable with the workpieces before the V "blocks are positioned to engage under theends of the workpieces whereby said pads press the workpieces downwardly against the V blocks when the hoisting mechanism is operated to raise the slide.

V "3. A mechanism for transferring workpieces through a series of "stations comprising work ward projections engageable under the terminal portions of said workpieces, means for, actuating the arms in each pair toward and away from each other and into and out of engagement with a workpiece, means co-ordinating said actuator means for simultaneous operation, an elongated slide commonto and carrying all of said work-carrying arms mounted to travel in a direction substantially parallel to said series of stations for moving each pair of said workcarrying arms back and forth between said stations, and a hoisting mechanism carrying said slide for moving the latter together with the work-carrying arms associated therewith vertically with respect to said work-supporting means.

RALPH E. CROSS. 7

References Cited in the file of this patent UNITED STATES PATENTS Number Platz Aug. 13, 1942