US2694994A - Air operated ejector for presses - Google Patents

Description

Nov. 23, 1954 Filed May 27, 1950 G. J- WEYMOUTH ET AL AIR OPERATED EJECTOR FOR PRESSES 2 Sheets-Sheet l Zinnentors (lttomegs Nov. 23, 1954 ,J. WEYMOUTH ET AL 9 AIR OPERATED EJECTOR FOR PRESSES Filed May 27, 1950 2 Sheets-Sheet 2 62 5b 69 5/ 49 w fi 44 8/ 46 WWF/P Zhmentora' United States Patent AIR OPERATED EJECTOR FOR PRESSES George I. Weymouth and William C. Cooper, Bridgeport, Conm, assignors, by mesne assignments, to Cooper Weymouth, Incorporated, Bridgeport, Conn., a corporation of Connecticut Application May 27, 1950, Serial No. 164,688

2 Claims. (Cl. 11350) This invention relates to work ejectors for ejecting work pieces from a machine after the completion of a working or forming operation, and more particularly it relates to ejectors employing fluid pressure in the form of a relatively short sudden blast of air, for example, to accomplish the ejecting operation.

Heretofore, such ejectors have usually delivered an air blast directly against the work piece to be ejected. In power presses, for example, a ram controlled mechanism is operated after each stroke of the ram to direct a short, sharp blast of air against a work piece and blow it from the forming die or other Work holder under the ram. However, ejection by this means is not sufficiently positive to be entirely reliable. Frequently the work piece will stick to the die or other holder and will not be ejected, with resulting damage to the work or the machine, or both, on the next operation of the ram.

An object of the present invention is to provide a work ejector employing a blast of fluid pressure, but constructed and arranged to positively eject a work piece.

A further object is to provide a pneumatically operated positive work ejector capable of use with the standard air blast supply and control equipment heretofore employed in connection with conventional air ejectors.

A further object is to provide an ejector having a pneumatically operated ejecting member arranged to be instantly retracted upon completion of the ejecting operation to avoid any interference with the operation of the associated ram.

With the foregoing and other objects in view, We have devised the construction illustrated in the accompanying drawings forming a part of this specification. It is, however, to be understood the invention is not limited to the specific details of construction and arrangement shown, but may embody various changes and modifications within the scope of the invention.

In these drawings:

Fig. 1 is a side elevation of an ejector mechanism constructed in accordance with one embodiment of the invention, and showing one arrangement for mounting the ejector on an associated press;

Fig. 2 is a perspective view showing a different arrangement for mounting the ejector shown in Fig. 1;

Fig. 3 is a longitudinal section of the ejector shown in Figs. 1 and 2;

Fig. 4 is an elevation of the fluid pressure cylinder forming a part of the ejector shown in Fig. 3;

Fig. 5 is an end elevation of the cylinder shown in Fig. 4;

Fig. 6 is an elevation of the plunger and plunger rod forming a part of the illustrated embodiment;

Fig. 7 is an end view thereof;

Figs. 8 and 9 are side and end views respectively, of a detail, and

Fig. 10 is a side view of a work piece to be ejected looking from the right of Fig. l.

The ejector of the present invention is designed to be mounted in any suitable manner, for example on a universal supporting fixture permitting adjustment of the ejector to the proper position; or it can be rigidly supported as a permanent part of the machine. In Fig. 1 the ejector 11 is mounted in a supporting bracket 12 having an arm 13 vertically adjustable on an upright supporting post 14 which is secured in a bracket 15 horizontally adjustable on a supporting shaft 16 mounted on and extending outwardly from the machine bolster 17. The adjacent end of an air supply line 18 is connected to 2,694,994 Patented Nov. 23, 1954 the outer end of the ejector 11 and is mounted on a similar adjustable support including a bracket 21 vertically adjustable on a post 22, in turn supported by a bracket 23 for horizontal adjustment on the shaft 16. The press illustrated in Fig. 1 comprises a bed plate 24 supported on the bolster 17, and a ram 25, the reciprocations of which control the operation of the ejector. For example, a roller type tripper 26 is shown in Fig. l mounted on the ram in position to engage an angle or cam lever 27 on an air valve 28 to deliver a quick, short blast of air to the ejector 11 after the completion of each working stroke of the ram and the die is retracted. For this operation the tripper 26 is pivoted to yield upwardly on downward movement of the ram so as not to open valve 28, but does not yield on upward or retracting movement of the ram and so opens the valve for a short time on this movement. Compressed air is delivered to the valve 28 through a supply line 33 and shut-off valve 34. However, instead of applying this blast of air or other fluid directly to the work piece 29 in the die or work holder 31 on the bed plate 24 to eject it after it has been formed or shaped by the die 32 on the ram 25, the present invention is so constructed as to provide a positive ejection of the work piece 29 while continuing to employ the operating blast.

In Fig. 2, the ejector 11 is shown mounted on the back face 35a of the machine 35 as a permanent part of the machine. As shown, it is gripped between the lower jaws 36 of a bracket 37 for horizontal adjustment in an axial direction. The bracket 37 is in turn supported for horizontal adjustment in a direction at right angles to the ejector 11 on a supporting shaft 38 by upper jaws 39. Both upper and lower jaws 36, 39 are respectively clamped together by suitable clamping screws or bolts 40, 41.

The illustrated embodiment of the invention comprises a cylinder 44 having a plunger 45 slidable in the bore 46 of the cylinder with a sufliciently loose fit to permit some passage of trapped fluid past the plunger on the return stroke, as hereinafter described, for the purpose of facilitating the quick return of the plunger 45 after ejecting a work piece 29. A plunger rod 47 is integral with the plunger 45 and extends through a reduced bore 48 at one end of the cylinder 44. To prevent injury to the work piece as a result of being struck by the plunger rod 47, the end 49 of the rod is threaded for connection to a cap 51 of rubber, plastic or other suitable material and shape, depending upon the work piece to be ejected. As illustrated, a key, such, for example, as a pin 52, extends radially inward through a hole 53 and slidably engages a keyway 54 in the plunger rod to prevent turning thereof in the cylinder 44.

In the illustrated embodiment, the pressure end of the cylinder opposite the projecting plunger rod 47 is connected to the fluid pressure supply line 18 by a fitting formed by a cap 56 which, in effect, forms the end of the cylinder and has a threaded bore or pipe tap 57 forming a continuation of the inlet port 58 to the cylinder 44. The threaded end 59 of the line 18 is threaded directly into the bore 57. The inner end 61 of the cap 56 has an enlarged bore 62, the outer portion 62a of which is threaded to the external threads of an axial hollow stem 63 on the pressure end of the cylinder 44. An annular cushioned stop member 64 is mounted in the inner unthreaded portion 64a of the bore 62 in the cap 56 to form a stop for limiting the retracting or return movement of the plunger 45 and rod 47, and to accurately locate them when retracted. As illustrated, the stop member 64 is of laminated form with a center layer 65 of rubber, plastic or other suitable yieldable resilient material between outer protective layers 66 of steel or other harder protective material. This forms a cushion bumper or stop for the plunger. In the opposite end of the cylinder o'r bore 46 a resilient annularbumper 69 is provided to form a stop member for the plunger on its working stroke. As shown, it comprises an annular resilient ring 71 of rubber, plastic or other suitable material and a supporting bushing 72 of steel or other suitable relatively hard protective material. The bushing has a collar or flange 73 covering the inner face 74 of the ring 71 and a sleeve 75 extending through the ring and into a counterbore 76 at the end of the cylinder bore 46 around the plunger rod 47. The bushing protects the resilient collar 71 against being distorted out of shape by the repeated blows of the plunger 45 and hammered into the bore 48 around the plunger rod 47 with resulting trouble. The plunger 45 has a cylindrical extension 77 which strikes the collar 73 of the bushing 72 at the end of each working stroke of the plunger 45, and means is provided for quickly returning the plunger to retracted position. As illustrated, a helical spring 78 is compressed between the plunger 45 and the collar 73 on the bumper bushing 72, the end 79 of the spring adjacent the plunger 45 directly engaging the plunger and surrounding the plunger extension 77 which extends through the coils of the compressed spring to engage the stop collar 73 on the working stroke and also acts as an inner guide and support for the coils on compression.

The cylinder 44 is provided with radial exhaust ports 81 which are so located longitudinally of the cylinder as to be uncovered by the plunger adjacent the end of its working stroke, permitting the compressed air to escape and the spring 78 to retract the plunger immediately upon its reaching the end of the cylinder. A bleed or leak port 82 is provided in the end cap 56 at one side of the inlet port 58 to permit the air back of the plunger to escape and to enable the spring 78 to quickly return the plunger and rod to retracted position by allowing any fluid pressure that may be trapped ahead of the plunger 45 to escape through the leak port 82 on the return movement. At the same time, this operation is also expedited by the loose fitting of the plunger in the cylinder 44 by which trapped fluid can escape past the plunger 45 and out through the exhaust ports 81 during the return stroke, if necessary. The leak port 82 is so located with relation to the end of the supply line 18 and the inlet port 58 that the velocity of the fluid entering the cylinder through the inlet port has a jet effect which prevents the escape of any substantial operating pressure through the leak port 82 before operating the ejector plunger. If desired, flat wrench faces 83 can be provided on the outer face of the cylinder 44, and similar faces 84 on the end cap 56.

In operation, the cylinder 44 is mounted in properly adjusted position on a machine adjacent the forming or holding dies 31, for example, as shown in Fig. l, or permanently secured in place as shown in Fig. 2. In the case of a press, the ram 25 may actuate the blow valve 28 or its upward movement after the end of the rarns working stroke in the usual manner, delivering a short, quick blast of fluid pressure, usually compressed air, to the cylinder 44 through the inlet port 58 thereof, forcing the plunger 45 and rod 47 to the left as seen in Figs. 3 and 4, and to the right in Fig. 1, against the pressure of the spring 78. This operation drives the cap 51 on the end of the plunger against the work piece 29 with such positive force and a hammer blow as to eject it with dependable certainty from the die or holder 31. Adjacent the end of its stroke the plunger 45 uncovers the exhaust ports 81, permitting exhausting of the operating pressure from the cylinder 44 and permitting the return spring 78 to quickly retract the plunger and rod and get it out of the way of the ram 25 on its next stroke. The resilient bumper 69 cushions the end of the plunger stroke and assists in quickly reversing the plunger movement and initiating the return movement thereof. The spring 78 is able to act quickly as a result of the exhaust of the working fluid through the exhaust ports 81 and the escape of any trapped fluid through the leak port 82 on the return movement of the plunger 45, the looseness of the plunger in the cylinder being sufficient to also permit the escape of trapped fluid past the plunger and out the exhaust ports, if that is necessary.

The invention thus provides an ejector which operates on a work piece with a positive operation while employing a conventional air blast supply system and control mechanism. The plunger is retracted so quickly as to avoid interferring with the ram of a press or the like and without requiring any reduction in the speed of operation of the associated machine.

IHaving thus set forth the nature of our invention, we c arm:

1. A work ejector comprising a fluid pressure cylinder, 2:. plunger reciprocable therein, a work engaging and ejecting plunger rod connected to said plunger and projecting outwardly at one end of the cylinder, fluid pressure inlet means for delivering a short blast of plunger operating fluid pressure at the other end of said cylinder, said cylinder having exhaust ports located in the wall thereof spaced from the inlet and so as to be uncovered by said plunger to exhaust the operating pressure from said cylinder near the end of a working stroke of the plunger, an annular resilient bumper surrounding said plunger rod adjacent the first end of the cylinder to limit the working stroke of the plunger including a ring of resilient material surrounding said plunger rod and compressible against the adjacent end of the cylinder and a bushing of non-resilient material including a sleeve extending between said ring and said rod with one end extending into a counterbore in the end of the cylinder and a collar on the inner end of the sleeve interposed between the resilient ring and said plunger, spring means for returning said plunger to the inlet end of said cylinder, and a leak port adjacent the inlet end of said cylinder, so that after the blast is terminated the trapped fluid pressure is permitted to escape through said leak port and said means is enabled to quickly return said plunger to the inlet end of said cylinder.

2. A work ejector comprising a fluid pressure cylinder having a first end and an opposite inlet end, a plunger reciprocable therein and having a relatively loose fit in said cylinder to permit escape of fluid pressure past the plunger, 2. work engaging and ejecting plunger rod con nected to said plunger and projecting outwardly at the first end of the cylinder, fluid pressure inlet means at the other end of said cylinder, said cylinder having exhaust ports located in the wall thereof spaced from the inlet end so as to be uncovered by said plunger to exhaust the operating pressure from said cylinder near the end of a working stroke of the plunger, an annular resilient bumper surrounding said rod at the first end of the cylinder to limit the working stroke of the plunger and rod, including a ring of resilient material surrounding said rod and compressible against the adjacent end of the cylinder and a bushing of nonresilient material having a sleeve extending between said ring and rod with one end extending into a counterbore in this end of the cylinder and a collar on the inner end of the sleeve between the resilient ring and said plunger, a helical spring adapted to be compressed between said bumper and said plunger on the working stroke for returning said plunger to the inlet end of said cylinder, a cylindrical extension on said plunger located within said helical spring in position to engage said collar at the end of each working stroke, and a leak port adjacent the inlet end of said cylinder so that after the fluid pressure is cut ofif any trapped fluid pressure escapes through said leak port and past the loosely fitting plunger to said exhaust ports and said spring means is enabled to quickly return said plunger and rod to the inlet end of said cylinder.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 975,314 Baker Nov. 8, 1910 1,774,905 Smrdel Sept. 2, 1930 2,021,580 Osgood Nov. 19, 1935 2,071,752 Lloyd Feb. 23, 1937 2,122,648 Johnson July 5, 1938 2,173,358 Ernst Sept. 19, 1939 2,275,561 Sahlin Mar. 10, 1942 2,349,502 Koehler -2 May 23, 1944 2,367,515 Moon Jan. 16, 1945 2,482,280 Lerma Sept. 20, 1949

Images