US2500671A - Hydraulic press with continuously rotating dial - Google Patents

Description

Mrch 14, 1950 w. A. FLETCHER Erm.

HYDRAULIC PRESS WITH CONTINUOUSLY ROTATING DIAL Filed Sept. 5, 1946 5 Sheets-Sheet 1 INVENTORS March 14, 1950 w. A. FLETCHER ETAL 2,500,671

HYDRAULIC PRESS WITH CONTINUOUSLY ROTATING DIAL 5 Sheets-Sheet 2 Filed Sept. 5, 1946 March 14, 1950 w. A. FLETCHER Erm. 2,500,671

HYDRAULIC PRESS WITH CON'I'INUOUSLY ROTATING DIALl Filed Sept. 5, 1946 5 Sheets-Sheet 3 Va@ Mw@ Mx im "o INVENTOR Bv 'Mv March 14, 1950 w. A. FLETCHER ErYAL 2,500,671

HYDRAULIC PRESS WITH CONTINUOUSLY ROTATING DIAL I 5 Sheets-Sheet 4 Filed Sept. 5, 1946 March 14, 1950 w. A. FLETCHER ETAL HYDRAULIC PRESS WITH CONTINUOUSLY ROTATING DIAL Filed Sept. 5, 1946 5 Sheets-Sheet 5 l /l/l l /l /l/l/l/ Potented Mar. 14, 1950 HYDRAULIC PRESS WITH CONTINUOUSLY ROTATING DIAL William A. Fletcher, Basil S. Sample, and Max E. Todd, Anderson, Ind., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application September 5, 1946, Serial No. 695,000

2 Claims. (Cl. 113-45) This invention relates to presses for performing operations on work-pieces which are placed on workholders moved by a conveyor from a loading station to a position under the ram of a press. A press of this type is commonly known as a dial feed press, the conveyor being a rotatable table or dial which is moved intermittently. During the rest period of the dial, the ram of the press moves a tool against the workholder underneath. 4

- When handling certain kinds of Work-pieces, it

is not always convenient or practical to secure them to the workholders in a manner such that they will always remain in place upon the workholders during the starting and stopping of the conveyor or dial as it carries the work from the loading station to the work station underneath the press tool.

Therefore, it is an object of the present invention to provide a press having a continuously moving conveyor or dial and to provide for movement of the support for the press tool laterally with the dial during a portion of the dial movement so that the tool'will remain in alignment with the work While moving toward it. Accordingly, the disclosed embodiment of the invention comprises a conveyor such as a dial, carrying a plurality of workholders, means for moving the dial continuously, a ram for supporting a tool movable into engagement with the work on a workholder, means -for moving the ram toward and away from the work, means for causing the ram to move laterally with the conveyor during a portion of its movement when the tool carried by the ram moves into engagement with the work i and means for returning the ram laterally to a starting position.

The further objects and advantages of the present invention will beapparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Figs. l and 1A together constitute a plan view of a press embodying the present invention.

Fig. 2 is a front elevation;

Fig. 3 is a sectional View on line 3-3 of Fig. 1;

Fig. 3A is the top view of a piston rod shown in Fig. 3;

Fig. 4 is a s-ide elevation partly in section, the part in section being on the line 4-4 of Fig. 2;

Fig. 5 is a diagram of hydraulic circuits.

Referring particularly to Fig. 3, there is a base.

I0, or table top which is supported above the floor level in any suitablemanner, not shown. Base Ill supports a fixed rod II and a roller thrust bearing I2 which supports one arm I3 of a C- shaped frame I5 having an arm I4 also journaled on the rod II. Upward movement of the C- frame I5 is restricted by a roller thrust bearing I6 clamped against a shoulder I'l of the rod II by nuts I8 threaded on the rod and located in a recess I9 closed by a cover 20 attached to the frame I5. A dial 2| is journaled on the rod Il and is located between the arm I3 of the C-frame I5 and a collar 22 pinned to the rod Il. The weight of the dial 2l is transmitted to the base I0 through a thrust ball bearing 23, the hub of arm I3 of C- frame I5 and the thrust roller bearing I2. The dial 2| carries a plurality of workholders equiangularly spaced adjacent the periphery of the dial. One of these workholders is represented by the block 25 which obviously would be shaped to conform to. the Work-pieces. holder 25 is located for the press operation, it is above the plane surface 26 of a pad provided by the arm I3 of C-frame I5 so that the pressure exerted by the press tool upon the work tending to deflect the dial will cause the dial to be pressed against the surface 26.

The dial 2I is rotated continuously by an electric motor, not shown. Referring to Fig. 2, the

motor is connected by a belt drive with a pulley 30 which, through a speed reducing mechanism 3l, drives a shaft 32 connected by a coupling 33 with a shaft 34 journaled in-bearings 35 and 36 (Fig. 4) supported by a bearing frame 31 attached to the base I0. The shaft 34 provides a pinion 38 meshing with a gear 39 attached to the underside of the dial 2I. A gear ratio between the shaft 34 and the dial 2l corresponds to the number of workholders 25 on the dial. For example, if the dial carries twelve Workholders, the speed ratio of the shaft 34 and dial 2| is l2 to 1. Therefore, the pinion 38 may have twelve teeth and the dial 144 teeth. For each revolution of the shaft 34 the dial will rotate 30 which is the angular spacing of the twelve workholders on the dial.

Since the shaft 34 makes one revolution during each press cycle it may be used to control the movement of the press ram to be described. Accordingly, the shaft 34 drives a cam 40 which engages a roller 4I carried by a valve rod 42 of an oil pressure distributing valve 43 to be described. Valve 43 is supported by bracket 44 attached to the table III, said bracket `supporting also the speed reducing gear 3l.

The c-frame I5 includes a tubular part 50 (Fig. 3) which carries a sleeve 5I and a head 52 When the Workadjustment is made rotation of the piston is prevented by a lock nut 51.

The lower end of rod 55 provides a piston 58 fitting the inner wall of a cylinder or ram 59` which is guided for vertical movement by sleeve Axial rotation of the cylinder 59 is prevented by a key 60 which slides in a vertical groove 62 provided by the sleeve 5|. The key 60 is iixed to the cylinder 59 -by a nut 6I which has sliding t with theA rod 55 and which closes the upper end of the cylinder 59. The rod 55 is provided with passages 64 and 65 into which pressure oil is distributed by the valve 43 (Fig. 4). When passage 64 is connected with the pressure source and 65 is connected with drain, cylinder 59 will move down until the lower end of nut 6I engages 1 the upper side of the piston 58. When passage 65 is connected with the pressure source and passage 64 with drain, the cylinder 59 will move up until the nut 6| engages the flange 52a of head 52. The frame I5 provides an oil seal 66 for vpreventing the passage of oil downwardly from the lo-wer end of the cylinder 59. The oil which accumulates above the seal is conducted through passage 61 connected by a pipe, not shown, with drain or tank.

The lower end of the cylinder or ram 59 provides for attachment thereto of a tool for performing an operation upon the workpieces carried by the workholders.

ibut it will be understood to be one which is designed to perform a particular operation.

The head 52 supports a valve 10 moved into engagement with a valve seat 1I by a spring 12 which surrounds the valve stem and is conned between a surface 13 of the head and a washer 14 retained on the valve stem by a pin 15. The head 52 has a hole 16 which provides clearance around the valve stem. The valve 10 moves in a recess 11 closed by a nut 18. A passage 19, which is connected with one of the pressure lines to the The tool is not shown piston in a manner to be described, connects dial while the tool is moving into engagement with the work. For this purpose the dial is provided with pins 90 (Figs. 1 and 4) equi-angularly spaced and equal in number to the number of workholders 25. Acarried by the C-frame I5. Dog 9| is a lever attached to a shaft 92 which extends through a spacing collar 93 (Fig. 4) and through bearings 94 in a'bearing bracket 95 attached to the frame I5. A spring 96 which surrounds the spacer 93 urges the dog 9| clockwise as viewed in Fig. 1 or looking in the direction of arrow 91 (Fig. 4), said motion being arrested when a lever 98 attached to the lower end of the shaft 92 engages Each pin 90 engages a dog 9| a stop pin 99 fixed to the bracket 95. Lever 98 l carries a roller |00 for engagement by a cam surface |0I provided by a bracket |02 having a slot table or base I0 (Fig. 2).

Awithin the cylinder III urges an arm I| 4 clock- |03 through which screws |04 extend which are threaded into the table I0. The

an adjustment of the bracket |02.

The dial 2| rotates counterclockwise as viewed in Fig'. 1. Therefore, when the pin 90 engages `slot provides the dog 9| the C-frame I5 will move laterallyv with the dial about the dial axis O. Fig. 1 shows C-frame I5 in a. position represented by its center line C-O which is between its limits of travel. At that instant, the pin which engages the dog 9| is on line B-O and the pin 90' which is next to engage the dog is von line A-O. At a position to the right of C-O theipin 90 engaged this dog 9| and started movement of the frame I5. As the frame I5 starts moving with the dial 2|, cam 40 which rotates clockwise as viewed in Fig. l, causes the valve rod roller 4I to move up (Fig. 1) to cause valve 43 to be conditioned for effecting downward movement of the ram 59. A latch to be described maintains the valve 43 in that condition independently of the cam 40. Fig. 1 shows that the cam 40 is about to leave the roller 4|. At a position of the frame I5 to the left ofB-O, through the coaction of surface I 0I of bracket |02 and roller |00, the dog 9| will be moved counterclockwise away from the path of movement of the pin 90 so that the frame I5 can be returned by means to be described to a starting position at the right of C-O, and th'e dog 9| Iwill be returned by spring 96 (Fig. 4) to a position when the dog will be engaged by the next pin 90 which had lbeen moving to the left of A-O while the frame I5 had been moving to the left of C-O.

Before the disengagement of the dog 9| from roller 90, the cam 40 had entirely released the roller 4| so that by means responsive to the completion of the operation upon the work by the ram supported tool, the valve latch is retracted in a manner to be described and a spring causes the valve 43 to be conditioned for causing the ram 59 to be lifted.

The return of the frame I5 from a position to the left of C-O to a position to the right of C-O Is eiected by the instrument IIO commonly known as a door closer. The door closer I|0 comprises a cylinder II I having a mounting pad II2 attached to a bracket II3 supported by the A spring, not shown,

Wise (Fig. l) about its axis II5. Arm II4 Iis pivotally connected at I I6 with an arm I I 1 pivotally connected at I|8 with a lever II9 pivotally con' nected at I 20 with a bracket I2I which screws |22 attach to the frame I5. The door closer IIIJ includes a pneumatic or hydraulic check which retards the clockwise return movement of thel frame I5. The check can be adjusted to .vary the time of return of the frame I5 to a starting Iposition. 'I'he frame I5 -is timed to return to its starting position just before the next pin 90' moves into engagement with the dog 9|. Consequently the oscillation of the frame I5' is almost continuous. The object is to return the frame I5 to its starting position just in time for the dog 9| -to be engaged by the next pin 90 which is moving asodevi cylinder |31 receives a piston |39 which provides a valve which is held upon a seat |4| by the force of a spring |43 and by the pressure of oil above the piston |39, said oil entering through a small passage |42. A central passage |44 in the rod of piston |39 leads from a chamber |45 in the head |38 to a passage |46 below the seat |4I connected by pipe |41 with the tank. The head |38 is provided with a passage |48 connecting cylinder |31 with a valve seat |49 normally closed by ball valve urged against the seat by a spring |5|, the pressure of which is adjusted by screw |52.

The passage |34 is connected by pipe |54 with port provided by the body |56 of the valve unit 43. A port |51 is connected by pipe |58 with passage 64 in the piston rod 55. A port |59 in body |56 is connected by pipe |60 with passage 65 in the piston rod 55. The valve body |56 provides exhaust ports |6| and |62 connected by a passage |63, connected by pipe |64, connected with pipe |41. Pipe |65 connects pipe |60 with passage 19 leading into the chamber 11 of the head 52 as shown in Fig. 3. Passage 80 is connected by pipe |66 with pipe |41. The valve rod 42 provides a land |10 for controlling ports |51 and I6| and a land |1| for controlling port |59 and |62. A spring |12 urges the valve rod 42 toward the right so that the roller 4| (Fig. 4) may engage the cam 40. The valve rod provides a shoulder |13 for engagement by a -pin |14 extending from a piston |15 received by a cylinder |16 provided by the valve body |56. A spring |11 urges the piston |15 upwardly in Fig. 5. A pipe |18 connects passage |48 of the valve unit |35 with the cylinder |16.

Fig. 5 shows the status of the valve 43 after the cam 40 (Figs. 1 and 4) has moved the valve rod 42 left into the position shown in' Fig. 5 to lpermit the spring |11 to push the pin |14 between the shoulder |13 and the land I1|. The valve rod 42 is then held in that position temporarily independently of the cam action. The pump is then connected by passage |34 and pipe |54, port |55, |51 and pipe |58, passage 64 with the lower side of piston 58 thereby causing the cylinder or ram 59 to move downwardly to cause the tool carried thereby to engage the work. When the tool has completed its operation, downward movement of the ram 59 ceases and pressure increases in the -passage |34 of the valve unit |35. When the pressure exceeds the limit for which the spring |5| is adjusted, the ball valve |50 opens and Ipressure above the piston |39 decreases because oil can discharge from the cylinder |31 through the passages |48 and |44 faster than it can enter through the smaller passage |42. Then the spring |43 is no longer able to maintain the piston |39 down; and the valve |40 lifts from the seat |4| thereby permitting the pump to discharge back to the tank through the pipe |41.

When pump pressure is thus relieved the pressure in the cylinder |16 of the valve unit 43 de creases and the pressure within the valve body |56 acting upon the stop pin |14 and the upper end of the piston |15 is sufficient to overcome the spring |11 thereby pushing the pin |14 away 'i from the shoulder |13 whereupon the spring |12 6 |55 and |59 while'land |10 blocks communication between ports |55 and |51 and permits connection between port |51 and |6|. Therefore, While piston rod passage 64 is connected by the pipe |64 with tank, piston rod passage 65 is connected with pipe |54. Therefore, pressure iluid is being admitted to the upper side of the piston 58 while the lower side is connected with the tank. Therefore the cylinder or ram 59 will movel up. As it does so, it lifts the valve 10 for the purpose of relieving pressure on the pump independently of the action by the valve unit |35. Because the piston rod 55 and the head 52 are movable laterally with the C-frame I5, the pipes |58, |60, |65 and |66 are provided respectively with flexible sections |56a, |60a, |65a and |66a.

The attendant who loads the workpieces on.

the workholders usually sits in front of the dial as viewed in Fig. 2, which is below Fig. 1. It has been found that there is no disadvantage to the attendant to load a Workholder on a continuously moving dial. The attendant soon becomes accustcmed to the steady movement of the dial. In fact it is less trying to load a steady moving dial than one which stops and starts intermittently. Since more than normal loading time may be consumed in loading a workholder it may happen that the attendant is still loading the dial when it suddenly starts moving. He may not then be ready to release the part he has placed on the workholder, and the part may become dislodged before he releases hold of it. With a continuously moving dial this difliculty is not present. Furthermore, there is no jerking of the dial by starting and stopping such as to dislodge the pieces which the attendant has placed upon the workholder. Therefore, for certain kinds of work where it is not practical or convenient to clamp the workpieces to the workholder or secure them in a manner which will resist any -jerking of the dial, a press having a continuously moving dial is a decided advantage.

vThe guard |25 (Fig. 3) which is attached to the table I0 protects the attendant from the gear 39.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scopel of the claims which follow.

What is claimed is as follows:

' 1. A press comprising a conveyor carrying work holders for supporting work pieces, means for moving the conveyor continuously, a ram for supporting a tool which `engages a work piece when aligned with the ram, an hydraulic servomotor for moving the ram toward and away from the work piece in alignment therewith, an oil supply tank, a pump for forcing oil from the tank under pressure to the hydraulic means, a valve for controlling the application of pressure oil to the servo-motor, said valve being actuatable into a status for causing the ram toV move toward the work piece and being actuatable into another status for causing the ram tomove away `vfrom the work piece, cam operated means cowill move the valve rod 42 to the right. The cam y 40 is so constructed that before downward movement of the ram is arrested the low land of the ordinated with movement of the conveyor for causing the valve to be actuated into the first status, a spring for causing the valve to be actuatedinto the second status, a latch for temporarily holding the valve in the rst status, a pressure relief valve responsive to the application of a certain pressure by the ram on the work piece for causing the load on the pump to be relieved, means responsive to action of the pressur@ relief 'valve for causing retraction of the latch whereby the spring can actuate the valve into the second status, means for causing the ram to move laterally with the conveyor during a portion of its movement when the ram .is aligned with the Work piece, and means for causing lateral return movement of the ram to a starting position.

2. A press comprising a conveyor carrying work holders for supporting work pieces, means for moving the conveyor continuously, a ram for supporting a tool which engages a work piece when aligned with the ram, an hydraulic servomotor for moving the ram towardV and away from the work piece in alignment therewith,v an oil supply tank, a pump for forcing oil from the tank under pressure to the hydraulic means, a

valve for controlling the application of pressure oil to the servo-motor, said Valve being actuatable into a status for causing the ram to move toward the work piece and being actuatable into another status for causing the ram to move away from the work piece, cam operated means coordinated with movement of the conveyor for causing the valve to be actuated into the first status,

'a spring for causing the valve to be actuated into the second status, a latch for temporarily holding the valve in the first status, a pressure relief valve responsive to the application of a certain pressure by the ram on the work piece for causing the load on the pump to be relieved, means responsive to action of the pressure re- `REFEREN CES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 441,260 Tybel'g Nov. 25,v 1890 1,136,275 Roenrich Apr. 20, 1915 1,692,771 Ferris Nov. 20, 1928 2,028,225 Larson Jan. 21, 1936 2,055,530 Hallenbeck Sept. 29, 1936 2,122,356 Bullard June 28, 1938 2,249,964 Lindner July 22, 1941 2,276,979 Jacobi Mar. 17, 1942 2,362,054 Denison Nov. 7, 1944 2,425,170 Wunsch Aug. 5, 1947

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