US2867185A - Transfer mechanism - Google Patents

Description

Jan- 6, 1959 c. E. HAYWARD 2,867,185

TRANSFER MECHANISM Filed Dec. 15, 1955 2 sheets-sheet 1 a7 62h ee a9 9o k\ s6 a5 l /j/ I 79 93 9| 3 92 I al m FIG. 5

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Jan. 6, 1959 C, E, HAYWARD 2,867,185

TRANSFER MECHANISM Filed Dec. l5, 1955 2 Sheets-Sheet 2 INVENTOR.

CHARLES E. HAYWARD ATTORNEYS United States Patent C) N' 2,867,185 TRANSFER MECHANISM ICharles E. Hayward, Alma, Mich., assignor to The Lobdell-Emery Manufacturing Company, Alma, Mich., a corporation of Michigan Application December 15, 1955, Serial No. 553,300

7 Claims. (Cl. 113-50) This invention relates broadly to transfer equipment and more particularly to apparatus for mechanically unloading stampings or the like from the dies of a press or similar machine without interrupting the operation of the machine.

As is well known in the art, manufacturers of this type of equipment have always sought to design transfer apparatus so that relatively little damage would result if the press ram ever struck the apparatus. Because there is always a very real danger that the timing of either the ram or transfer mechanism may be upset by some operational failure, designers have been prone to employ pneumatically operated mechanical grippers which grasp only an edge of the workpiece and need not move any appreciable distance in between the die elements. This design is recognized to be disadvantageous because a great many stampings cannot be gripped by an edge Without providing clearance slots in the die for the grippers, and this practice is costly, and in many cases not possible.

However, it has been thought practical` to minimize the risk that costly dies, and possibly the press and the transfer mechanism as Well, might be severely damaged, perhaps beyond repair.

One of the prime objects of the instant invention is to provide transfer mechanism having an operating arm or arms which can safely extend in between the die members because the mechanism incorporates elements cooperable with the ram for mechanically withdrawing the arm or arms in the event the pressure uid system for withdrawing them should fail. The transfer mechanism which I will disclose must be withdrawn from between the dies of the press before the ram can descend and accordingly the possibility of accidents in the press room resulting because the ram strikes the transfer apparatus is eliminated.

Another object of the invention is to design transfer means of the character described which can employ suction cup means for engaging the blank, this construction preventing marring of the surface which frequently occurs when mechanical grippers are used, and enabling a far greater variety of workpieces of all shapes and sizes to be unloaded or loaded as desired.

A further object of the invention is to design transfer mechanism which can very easily handle large and irregular shaped castings with a rapidity which greatly increases the productive capacity of a press.

A further object of the invention still is to design transfer means of the type described which can lift stampings that cannot be lifted by conventional edge gripping jaws, and can also lift stampings from a die which could not be slotted for jaw or gripper access and could not normally be mechanically unloaded.

Another object of the invention is to design transfer mechanism of simple and practical construction which is highly eflicient and reliable in operation and can be employed very conveniently in plants where available operating space is limited.

A still further object of the invention is to design 2,867,185 YPatented Jan. 6, 1959 transfer mechanism of rugged and durable construction which can be very economically manufactured and assembled.

With the above and other objects in view, the present invention consists in the combination and arrangement of parts hereinafter more fully described, illustrated the accompanying drawing, and more particularly pointed out in the appended claims, it being understood thatequivalent changes may be made in the various elements which comprise the invention without departing from the lspirit thereof or the scope of the appended claims. I

In the drawings- Fig. 1 is a sectional side elevational view of the transfer mechanism showing the work lifting and withdrawing element in out position moving toward the dies of a press.

Fig. 2 is a similar view showing the element swung in between the dies and lowered to bring' the suction cup into engagement with the workpiece, the broken lines indicating the manner in which the workpiece is irst lifted kout of the die prior to its withdrawal laterally.

'Fig 3 is a fragmentary view similar to Figs. l and 2 illustrating the positions of the elements when the' work transferring member is in the position in which it 4is shown in broken lines in Fig. 2.

Fig. 4 is an enlarged, sectional, elevational view illustrating the operation of the valves which control the pressure fluid actuating cylinders, the cylinder shown being arranged as shown for convenience in drawing.

Fig. 5 is a similar view of a valve which may be used to control the suction member. ,n

Referring now more particularly to the accompanying drawings wherein I have shown a preferred embodiment of the invention only, a letter F generally indicates the frame of a conventional press such as a stamping press which has as usual a bed 10 with a lower die 11 secured thereon.` A ram R reciprocates vertically in guides G in a stamping stroke and has a punch or upper die 12 thereon cooperable with the lower die 11 to stamp out a workpiece W from a suitable blank. The ram R will be continuously driven in the usual manner by mechanism such as that shown in Fig. l which it is not necessary to describe since it is well known and forms no part of the instant invention. The transfer mechanism, which will now be described, is shown as unloading the stampings from the press to a rearward position or stack. As will later be apparent identical apparatus could as easily be employed to load the blanks into the y press.

Supported from the stationary frame F of the press by brackets 13 is a main transfer mechanism frame or support plate 14 on which a reciprocable support or slide frame 15 may be mounted. Suitable guides will be provided on the frame 14 in which the slide frame 15 can travel to andA fro vertically and it will be seen that the frame 15 is connected by an arm 16 to the piston rod 17 of a double acting, uid pressure cylinder 18 and that the piston of the cylinder moves the frame 15 up and down. The cylinder 18 is supported by the main frame 14 on a bracket 19 which serves as an upper stop for the slide 15, and lines 20 and 21 lead into opposite ends of the cylinder 18 as shown. n

Mounted on the slide frame 15 is an outwardly extending support plate 22 and a pair of arms 23 are pivotally suspended from the plate 22 as at 24 and 25. A tubular work transferring or support element 26 has angular clamp straps 27 pinned to the arms 23 at 28 which support the element 26 in horizontal disposition from the plate 22 regardless of the angular position of arms 23. A vacuum cup 29 having a passage 30 ktherethrough is mounted on the front or inner end of the tubular element 26 and a line 31 leads from the opposite end of the element to a vacuum source.

1The member 32 which supports the inner arm 23 on` pin 24 is aV bell crank lever which is connected' at its l vOpposite end to the piston 33-of a double acting c'ylinder 34. The latter cylinder 34 is pivotallysupported by a bracket 35 on plate 22 and has lines 36 and 37 leading into opposite ends thereof.

The cylinders 18 and 34 normally control the unloading stroke of the lifting element 26 in a manner `which will be described, however, in the event of an operational l failure, a safety mechanism or means is provided which p islmoved directly by the ram to Ylift the element 26 and swing it out of the path of the ram R. The main support frame 14 is slotted as at 38 and a bell crank lever 39 pivoted on a bracket as at 41 has an arm or end with a lroller 42 thereon extending through the slot 38 into a bushing 43 provided in the slide frame 15. The bracket 40 and lever 39 are laterally outward of the vertical path `of a cam 44 on the ram R, however, a roller 45 -on the opposite end of the lever 39 is disposed in the vertical path of travel of the cam 44.

Below the lever 39 is a slide or tappet 46 with a roller 47 thereon which is also disposed in the vertical path of the cam 44 on the ram. The slide 46 is mounted in a bushing 48 on the slide frame 15 and frame 14 is slotted t as at 49 to permit Vertical movement of the bushing 48 and slide 46 with relation thereto.

It will be seen that the rear end of tappet 46 is enlarged as at46a to engage the bushing 48 and limit the distance the tappet 46 can be moved forwardly and this end 46a has a pin 50 receivable in a vertically, elongated slot 51 provided in the l lever member 32 so that it is movable-with the inner l arm 23 or can move the arms if necessary.

y :The compressed air cylinders `18 and 34 are operated by a pilot andmaster valve system which is illustrated in Fig. 4. The cylinder 18 is` shown connected to a schematically depicted master valve 52 by the lines 36 and 37. The valve cylinder 52 has a non-rotatable slide i 53 which has annular grooves 54 and 55 therein and a central recess 56 with a pair of bores 57 and 58 communicating therewith. Axial ports 59 lead from the recess 56 through to the ends of the slide 53 and lateral lports 60 and 61 in the side wall of the master cylinder 52 of the master valve 52 leads. A spring 69 normally maintains the valve 67 on its seat 70 so that the portion 68a of chamber 68 which leads to atmosphere is closed off.

Pivotally mounted on the valve as at 71 is a trip arm 71a which when actuated moves the valve member 67 olf its seat and exhausts air from the chamber 68 to atmosphere. Fig. 4 shows the slide 53 at the right end of the valve 52 as it would be after the pilot valve 65 was tripped by the member 72 on the ram R as the latter moved upwardly (Fig. 1), and, of course, the piston 33 is being forced downwardly. When the valve was tripped and air was exhausted from its chamber 68 a pressure unbalance was created within master valve 52, the pressure at the right end of slide 53 being decreased so that the slide moved all the way to the right as shown. Compressed air from the line 62 was then able to reach the cylinder 34 through recess 56, port 58, and line 36 and move the piston 33. Simultaneously air from the other side .of piston 33 is exhausting to atmosphere through line 37, annular grooveV 54, and port 60. Later when the lpilot valve 66 is tripped the air'at the left end (Fig. 4) of master valve cylinder 52 will be exhausted and a pressure unbalance will be created which will move slide 53 to the left. Compressed air will then feed into the cylinder 34 through recess 56, port 57, and line 37 to return piston 33 to original position. When the slide 53 is at the left end of the master cylinder valve 52, air from the upper end of cylinder 34 exhausts through line 36, groove S5, and port 61 to atmosphere. The reduced axial ports 59 are, of course, for replacing the air bled to atmosphere via the pilot valves. It is to be understood that other master and pilot valves which will be referred to may be of exactly the same construction as those just described. n

In the operation of the transferapparatus the pilot vvalve 65 is as noted tripped by a shoulder 72 on the ram -wise direction. This movement continues until the suction cup 29 is disposed substantially centrally over the stamping W as in Fig. 2. Just prior to completing its forward swing a lateral projection 73 on one of the arms 23 trips a pilot valve 74 which is in communication with master valve 75 through line 76 and causes master valve 75 to be actuated such that air is forced into the cylinder 18 through line 20. The piston 17 yis forced downwardly and slide plate 15 moves downwardly until the. cup 29 engages the workpiece W. During the downward passage of plate 15 a shoulder 77 on member 22 trips a pilot valve 78 which operates a control valve 79 (Fig. 5) in a manner which will be described to bring the line 31 into communication with a vacuum source.

As the slide 15 reaches the bottom of its downward stroke a pilot valve 80 which is in communication with master valve 75 through line 81 is tripped by a shoulder 82 on the plate 15 to actuate master valve 75 to admit air into the cylinder 18 through line 21 and raise slide 15 to its former position. The workpiece W, of course, moves vertically with the cup 29and when shoulder 83 on an upper extension of piston rod 17 trips pilot valve 66 master valve 52 is actuated to admit air through line 37 and the piston 33 is returned upwardly. In this manner the arms 23 are swung outwardly from between the dies and at the end of their outward or rearward travel the outer strap 27 trips a pilot valve 84 which actuates valve 79 (Fig. 5) to disconnect the vacuum sourceso that the cup 29 drops the workpiece W. The cup 29` drops the workpiece on top of a stack of similar workpieces and the cycle is ready to be repeated again after the immediately following forming stroke of the ram R.

In Fig'. 5 I have illustrated a valve 79 which is suitable for controlling the operation of the cup 29 and operates in the same manner as the master valves 52 and 75. Lines 85 and 86 lead from the pilot valves 78 and 84 respec-y tively and a non-rotatable slide 87 is mounted therein. Line 62b leads from a source of compressed air and communicates with a recess 88 in the slide which replenishes the air exhausted from the pilot valves in the operation of the valve 79 through passage 89 and an axial port 90. The slide 87 has also a recess 91 with line 31 and a vacuum line 92 in communication therewith when the slide is in the position illustrated. A port 93 in the valve wall leads to atmosphere so that the vacuum in line 31 is replaced'by air at atmospheric pressure when the pilot valve 84 is tripped and the slide 87 moves to the left. The pilot valves 78 andy 84 operate the slide 87 by creating.V pressure differentials at ythe ends thereof in the same manner as the slides in master valves 52 and 75-are operated.

If, when the lifting element 26 is in between the dies yof the press, the air cylinders or valves should refuse to operate or operate properly t0 withdraw the. work carrying element 26, the ram R in its forming stroke will as Roller 45 would rst be contacted by the angular surface 44a of cam 44 as the ram descends and would be forced outwardly so that slide was raised. The vroller 47 on tappet 46 would then be engaged by the surface 44a and forced outwardly to swing arms 23 outwardly and force the work carrying element 26 outwardly. With a safety return mechanism of this nature ready in case of an operational failure in the compressed air system, clearly designers need not fear specifying the more advantageous suction gripper which extends a substantial distance in between the dies and never distorts the workpiece in removing it as conventional edge grippers frequently do.

It should be apparent that I have perfected a considerably improved transfer mechanism which will find wide use in industry. While I have shown the apparatus operating as an unloader obviously it could as easily be used to load blanks into the press by adjusting the operation of the valve 79 so that the cup 29 drops the workpiece when the lifting element 26 is between the dies and picks up another blank when the element 26 is in out position. It is therefore not to be thought that, because for convenience sake I have shown an unloader, I intend to restrict my invention in any Way.

It is to be understood that the drawings and descriptive matter are in all cases to be interpreted as merely illustrative of the principles of the invention rather than as limiting the same in any way sinceit is contemplated that various changes may be made in the various elements to achieve like results without departing from the spirit of the invention or the scope of the appended claims.

I claim:

l. In work transfer apparatus for a press or like machine, the combination with the reciprocating ram and stationary frame, including the bed of the machine, of a support reciprocable on said frame parallel to the ram, a work engaging element, at least one pendant arm pivotally mounted on said support supporting said element, first power actuated means remote from the ram operatively connected to said arm for swinging the arm and moving the element in between the ram and bed and out therefrom, second power actuated means remote from the ram and operatively connected to said reciprocable support for normally moving the latter toward said bed when the element is in between the ram and bed to lower said element, and for returning the support in the opposite direction to raise said element prior to removing it, and means mounted on said frame and connected to said support so as to be normally moved out of the path of said ram by said first and second power actuated means concurrently with said pendant arm and support by the ram on its forming stroke for actuating said reciprocable support and said pendant arm to raise the element and move it out from betwen the ram and bed in the event the first and second power actuated means fail.

2. The combination defined in claim 1 in which said rst mentioned power actuated means comprises a pressure fluid cylinder activated to swing the arm inwardly when the ram commences its return stroke and to swing the arm outwardly when the reciprocable support has returned, and said second mentioned power actuated means comprises a pressure fluid cylinder activated to lower the element when the arm has swung inwardly and to raise the element when the support has reached the bottom of its stroke. p

3. The combination defined in claim l in which said element is tubular and has a suction member thereon, and means for connecting |and disconnecting said element to a vacuum source.

4. In work transfer apparatus for a press or like machine, the combination with the reciprocating ram and stationary frame, including the bed of the machine, of a support plate ixed to the frame of the machine, a slide plate vertically reciprocable on said support plate, said support plate having a pair of lvertically elongated and 6 spaced openings therein, a cam surface on said ram, a bell crank lever having one end extending through the upper opening in said support plate into engagement with said slide plate, the opposite end of said lever being disposed in `the path of the cam surface of the ram except when the slide plate is in up position, atleast one pendant arm pivotal on said slide plate and having a work engaging, substantially horizontally disposed element supported on the lower end thereof, an inwardly extending tappet connected to the arm and extending through the lower slot in the support plate into the path of the cam surface on the ram except when the work engaging element is in out position, means for swinging said arm inwardly to dispose thel work engaging element in lbetween the ram and bed and the tappet in the path of the ram, means for lowering the slide plate and thereby lowering the element toward the bed from said latter position, said bell crank lever being pivoted into the path of the ram when the slide plate is lowered, the down stroke of the ram Ibringing the cam surface firstly into engagement with the bell crank lever to pivot the same out of engagement therewith and raise the slide plate and work engaging element and secondly into engagement with the tappet to force the latter outwardly and swing said arm outwardly to return the work engaging element to out position.

5. The combination defined in claim 4 in which said means for swinging said arm inwardly comprises a pressure fluid cylinder normally also returning said arm and thereby said work engaging element and tappet to original position, and said means for lowering the slide comprises a pressure uid cylinder normally also returning said slide and thereby said bell crank lever to original position.

6. The combination defined in claim 4 in which the cam on the ram comprises a block with an inwardly and downwardly inclined surface.

7. In work transfer apparatus for a press or like machine, the combination with the reciprocating ram and stationaryframe of a support plate xed to the frame of the machine; a slide plate vertically reciprocable on said support plate; a cam surface on the ram; a bell crank lever pivotal on said support plate having one end extending into engagement with said' slide plate and the other end being disposed in the path of the cam surface of the ram except when the slide plate is in up position; at least one pendant arm pivotal on said slide plate and having a work engaging element supported on the lower end thereof; an inwardly extending tappet connected to the arm and extending into the path of the cam surface on the ram except when the work engaging element is in out position; means for swinging said arm inwardly to dispose the work engaging element between the ram and frame bed, and the tappet in the path of the arm; and means for lowering the slide plate Iand thereby lowering the element toward the bed from said latter position, said bell crank lever being pivoted into the path of the ram when the slide plate is lowered, the down stroke of the ram bringing the cam surface firstly into engagement with the lbell crank lever to pivot the same out of engagement therewith 'and raise the slide plate and work engaging element and secondly into engagement with the tappet to force the latter outwardly and swing said arm outwardly to return the work engaging element to out position.

References Cited in the file of this patent UNITED STATES PATENTS 1,797,239 Newman Mar. 24, 1931 2,233,935 Blackhouse Mar. 4, 1941 2,275,561 Sahlin Mar. 10, 1942 2,609,776 Sahlin Sept. 9, 1952 2,615,713 Blackhouse Oct. 28, 1952 2,677,342 Miller May 4, 1954

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