US2350217A - Hydraulic press control - Google Patents

Description

May 30, 1944.

P. c. COLLINS HYDRAULIC PRESS CONTROL Filed June 17. 1940 5 sheets sheeg 1 Paul. C. C OLLINS ATTORNEY May 30, 1944. P. c. COLLINS HYDRAULIC PRESS CONTROL Filed June 17, 1940 5 Sheets-Shoat 2 0 2 6 [ll -1- I m TI: \.i x m 4 6 3 5 5 l a 7 3 w 2 a 2 4 2 I 5 3 7 2 4 3 6 2 6T INVENTOR PRUL C. COLLINS ATTORNEY May 30, 1944. P. c. COLLINS 2,350,217

HYDRAULIC PRESS CONTROL Filed June 17, 1940 5 Shegts-Sheet 3 O INVENTOR PAUL C. C OLLINS mmzwuc rnnss conwnoz. 7

Filed June 17. 1940 5 sheets-sheet 4 ueuml INVENTOR PnuL C. COLLINS 21/ 4g g A'ITORNEY Patented May 30, 1944 HYDRAUIJOPBESS CONTROL Panic. Collins, Norwood, Pa., assignor to The Baldwin Locomotive Works,

Pennsylvania a corporation of Application June 11, 1940, Serial No. 341,046

8 Claims.

This invention relates generally to hydraulic presses and more particularly to improved control means therefor.

The hydraulic press shown herein is of the customary type having a movable platen operated by a main cylinder and ram and by pullback rains and cylinders, the fluid pressure being supplied alternatively to said cylinders from any suitable source such as a reversible hydraulic pump which is shifted selectively to its forward pressure position, to its reversing pullback position or to its neutral position to hold the movable platen in its uppermost position, or, if desired, fluid pressure may be supplied from a continuous source such as a uni-directional discharge pump or from an accumulator system in which cases fluid pressure is alternatively supplied to the main and pullback cylinders through a well-known reversing valve. This reversing valve and its source of pressure are equivalent to the fluid distributing function of the reversible pump mechanism although a reversible pump is shown herein for the purpose of illustration.

One object of the present invention is to provide an improved cam mechanism for controlling and shifting the fluid distributing means,

this cam mechanism being operated in synchronism with the platen movements. A further 'object is to provide an improved cam mechanism whereby the timing of the movements of the press platen, such as the upper and/or lower limits of travel of the platen, may be individually or relatively varied with accuracy, dispatch and convenience, preferably while the press is in continuous operation.

Another object is to provide an improvedvolumetric control for the pumping mechanism, this control being applicable during either the pressing or return stroke although duplication of the control adapts it to both strokes.

A further object is to provide an improved cam control mechanism in which the timing of the press controlled events are indicated on a suitable indicating mechanism that is instantly' and continuously visible to the operator. Another object is to provide an improved variable cam control mechanism that is relatively simple in construction, operation and maintenance and is compact and durable and has a high degree of sensitivity, accuracy and ease of operation, as well as being conveniently accessible to an operator at all times.

Other objects and advantages will be more lowing description of the accompanying drawings in which:

Fig. 1 is a diagrammatic illustration of my invention applied to a press which is only partially shown;

Fig. 2 is a vertical section of my improved cam control mechanism taken substantially on the lines 2-2 of Figs. 3 and 4; 1

Fig. 3 is a plan view of Fig. 2 but omitting the cam lobes for purposes of clarity;

Fig. 4 is a transverse section taken substantially on the lines 4-4 of Figs. 2 and 3;

Fig. 5 is a front elevation of Figs. 2 and 3 viewed from the left side thereof and Figs. 6, '7 and 8 are transverse section taken respectively on the lines 6-8, 1-1 and 8-8 of Fig. 2.

In the particular embodiment of the invention such as is disclosed herein merely for the purpose of illustrating one specific form among possible others that the invention might take in practice, I have diagrammatically illustrated in Fig. 1 one side of a hydraulic press having a base or stationary platen I joined by columns 2 to an upper stationary crosshead 3. The press is, of course, preferably symmetrically arranged but its details of construction do not enter into the present invention. A movable platen 4 is moved'downwardly during a pressing stroke by any suitable number of main rams and cylinders one set of which is generally indicated at 5 and is returned to itsupper position by usual pullback rams and cylinders generally indicated at 6. As is customary with hydraulic presses of this type during the initial portion of the pressing stroke pressure fluid is supplied to the main cylinders 5 from a usual filling tank (not shown) communicating through any suitable filling valve diagrammatically indicated at 1. After filling of the main cylinders with low pressure fluid during the initial portion of the pressing stroke the filling valve then closes and fluid under high pressure is supplied to the main cylinders from a pump diagrammatically indicated at 8, Fig. 1. This pump is to be considered for purposes of illustration as of the well-known variable positive displacement Hele-Shaw reversible type having uni-directional rotation driven by a suitable motor 9. Fluid pressure from this pump is alternatively supplied to the main and the pullback cylinders 5 and 6. For purposes of diagrammatic illustration, the pump is shown as connected to the main and the drawback cylinders by pipes l0, although it will, of course, be

apparent to those skilled in the art from the folunderstood that usual relief valves, by-pass about three-fourths of a turn. The cam mech-- anism controls the up and down movements of a rod l which is connected through a suitable bell crank l5a to a usual pump servo-motor diagrammatically indicated at I517. The cam mechanism, linkages and pump are shown in Fig. l in their neutral position. When the rod l5 moves upwardly the pump 3 is shifted so as to supply operating fluid to the main cylinders 5 for a pressing operation whereas when the rod I5 is moved downwardly the pump 3 is shifted to the other side of its center so as to supply operating fluid to the pullback cylinders 3 and draw fluid from the main cylinders. Excess or make-up fluid during either of these operations is taken care of by usual communication with the filling tank. The gear rack ll, Fig. 3, is prevented from rotating by a removable pin ll.

, The cam mechanism for controlling the distribution of operating fluid comprises, Fig. 2, a cam supporting disc l3 keyed to a sleeve I! which is journalled upon an inner sleeve l3, this latter sleeve being keyed as at- I! to shaft l3. Shaft I3 is Journalled in bearings 23 and 2| of a suitable stationary frame 22 mounted preferably at a convenient front portion of the frame. A second cam supporting disc 23 is journalled upon the disc sleeve H. A worm gear 24 is keyed at 23 to a hub of disc 23 while a similar worm gear 23 is keyed at 2'! to sleeve H of the other cam disc l3. An outermost disc 23 is keyed as at 33 to sleeve l3 and is secured .to shaft I3 through key l3. The sleeve and disc arrangement so far described is held in axial position by a nut 3| threaded on shaft l3 and engaging sleeve I 3, while an inner nut 32 threaded on sleeve l3 engages disc 23. To either adiust.or hold the cam discs l3 and 23 in a predetermined angular relation to each other and to the shaft I3, I provided a worm 33 meshing with worm gear 24 and transversely journalled in a suitable bracket 35 which is secured to the rear side of front disc 23 for bodily rotation therewith. A similar worm 33 meshes with worm gear 23 and is transversely journalled in a bracket 31 which also is secured to disc 23 for bodily rotation therewith. To rotate the worm 33 there is provided, as shown in Fig. 4, a pair of bevelled gears 33 secured respectively to worm 33 and to a shaft 33 which is journalled in disc 23, the front end of shaft 33 being provided with a hand grip 43. Similarly, the other worm 33 is provided with a pair of bevelled gears 4| whose axial shaft 42 is also journalled in disc 23 and provided with a hand grip 43. By manually rotating either or both of the knurled grips 43 and 43, the cam discs l3 and 23 may be relatively angularly adjusted thereby adjusting the extent of movements of the press platen as hereinafter described. To indicate the positions of the cam discs there is provided, as shown in Fig. 4, small worm gears 45 and 43 secured respectively to the worms 33 and 33 so as to rotate therewith. Small worm gears 41 and 43 mesh with the worms 43 and 43 and are suitably Journailed in the brackets 33 and 31 which are secured to the back side of disc 23. The worm gears 41 and 43 are mounted upon shafts which extend through disc 23 and carry on their outer face index dials 33 and 3|, Fig. 5, suitably graduated so that the angular position of the cam discs l3 and 23 may be indicated by suitable pointers-32 secured to the front face of disc 23.

The cam disc I3 is provided with a pump neutralizing cam lobe 33 secured in any desired fixed angular position with respect to disc 13 by bolts 34. A pair of cam lobes 33 and 33 is similarly secured to the second disc 23 as by bolts 51 and 53. To have the cam'lobes operate control rod l5, this rod is secured to a vertically movable crosshead 33 which is slidably guided in a crosshead guide 3| formed in the forward portion of frame 22 and provided, as shown in Figs. 3 and 5, with guide gibs 32 and 33. As shown'in Fig. 2, crosshead 33 has a shaft 34 extending therethrough and firmly held by an enlarged collar portion 33 and a nut 33. A pair of cam follower rollers 31 and 33 are journalled upon the outer ends of shaft 34. Rigidly secured to the lower end of crosshead 33 is a similar roller shaft 33 provided with a third cam follower roller 13. v

To manually shift the pump to any one of its three positions, namely, forward, neutral-or reverse, there is shown in Fig. 5 a hand lever 12 pivoted at 13 in a suitable stationary bracket 14 15 bearing against the under side of pin 13, Fig.

2, it being understood that the weight of rod l3 and crosshead 33 biases the crosshead and its pin 13 downwardly. To keep the hand lever 12 in a normally inactive relation 'to pin 13, a weight 11. Fig. 5. is pivotally connected by a rod 13, Fig. 2, to the bifurcated end of arm 13. The hand lever is thus normally maintained in its upper position 1211, Fig. 5. The frame 22 is supported on any suitable stationary part of the press frame or other stationary structure diagrammatically indicated in Fig. 2 at 13.

' To adjust the volumetric displacement of the pump, I provide an arm 33, Fig. 2,. pivoted at 3| to a stationary bracket 32. This arm has a pin. and slot connection 33 with a nut 34 which is non-rotatably but slidably supported on the base- 35 of bracket 32. An axially fixed screw 33 is threaded in nut 34 and has a hand grip 31 whereby rotation of the screw in either direction causes the nut 34 to move arm 33 upwardly or downwardly within a slot 33 of crosshead 33. To obtain any desired volumetric displacement of the pump for use on the pressing stroke and thereby determine the rate of pressing speed, the arm 33 is adjusted downwardly to a predetermined point at which it serves as a limit stop for the lower end 33 of crosshead 33. This limits the upward movement of the crosshead 33 beyond its neutral position and accordingdy limits thevolumetric displacement of the pump, it

being understood that the slot 33 is of sufilcient height that the'arm 33 may be adjusted upwardly to a point giving maximum volumetric displacement without having the upper end of the slot strike the arm. It will be understood that arm 30 is spaced from the lower end of slot 23 when pump neutralizing cam 33 is in engagement with roller 61 and hence this space allows crosshead 39 and pump rod Ilto be moved upwardly away from cam 33 to shift the pump of! of neutral to its forward or pressing position until lower end 39 strikes arm 30. Hence theextent to which the pump may be shifted wardly biasing but yieldable force of thrust or solenoid I29.

in its forward position to determine its volumetric displacement is controlled by the ad- .iustment of .arm 90. I

,'As shown in Fig. 5, three llm'tswitches diagrammatically indicated at I Is. In and m, provided respectively with pivotal actuating arms III, I39 and I34 are suitably mounted upon a portion of thestationary frame 22 or 39. These switch arms are actuated by various cams mounted upon certain of the cam discs, shown in Fig. 2, to be describedin connection with the operation of the equipment.

Operation The mode of operation of my improved cam mechanism will be more readily understood when described in connection with the control circuit of Fig. 1 which, for purposes of illustration, is of the electrical type.

The cam control of Fig. 2 and the circuit in Fig. 1 are shown in neutral with the press platen stopped in its upper postionwherein a switch H5 is closed by cam I6 thereby establishing a circuit from a current source I I5 through a solenoid Ill and a line H3, across a closed switch 9 and a line I to the other side of the current supply 8. Energization of solenoid'ill closes two swtches I2I and I22. The operator can now initiate down movement of platen 4 by closing a palm switch I23 whereby current is supplied from source IIB, thence through wire I24. across switches I2I, I23 and wire I25 to athrustorsoienoid I29 and thence back to the other side of the current supply IIB. Upon closure of palm switch I23, the switch II 9 is simultaneously opened to insure a single cycle control to be described later.

However, opening of switch I I9 does not interrupt the current for relay solenoid 1 because the circuit therefor connects from wire H3 across 9 switch I22 and wire I2'I to the other side of the current supply. Energization of solenoid I29 shifts the pump 9 to its full forward pressing pos tion, fluid being discharged from the pump to the main cylinders 5. It is desirable to have the operator keep his hands on the palm switch I23 so as to avoid injury during down movement of the press but when the press has moved down sufliciently so as to close the dies it is permissible for the operator to take his hands off of the palm switch I23. To do this it is necessary to maintain the solenoid I29 energized which is done by For reversing the' press in accordance with pressure, a pressure responsive switch "I opens automatically in response to a-predetermined main cylinder pressure. Opening of this switch automatically de-energizes thrustor solenoid I29 thereby allowing the weight of rod I6 and associated parts to shift the pump to its reverse position and thus supplyfiuid to the pullback cylinders 3. Rod I3 and crosshead 30 move downwardly until roller 63, Fig. 2, engages the cam 33, this cam limiting the extent of downward movement of roller 68 so that the-pump effects only a very restricted rate of reverse press movement if at'all. If a rubber pad or other resilient-means is interposed between the pressplatens as is ,re-

quired in some operations. then the foregoing restricted pump reversal avoids a sudden rebound of the movable press platen upon release of pressure in the main cylinder. For instance if the cam 58 is adjusted to give a very restricted press reversal, the resilient force will be controlled to' allow only agradual upward movement of the a cam 23' closing a switch I30 placed in parallel downwardly so as to partially reduce the pump stroke and thereby slow down the press speed. This partial down movement is against the uppress and even though th s is for a'short distance it will be sufficient to rotate disc 23 and hence move cam 56 out of the path of roller 39. This roller will thereupon drop until the roller engages the periphery of disc 23 and thus allow the pump to move past its neutral position and into reverse so as to supply operating fluid to the pullback cylinders and move the press upwardly. when the main cylinder pressure initially drops, the pressure responsive switch I3I immediately recloses but this will not allow re-energization of relay solenoid I" because top position switch 5 has been previously opened on the initial down stroke. The press w ll therefore continue upwardly until neutralizing cam 53, Fig. 2, engages roller 61 and shifts rod I5 and-thep'un'ip back to their neutral position thereby bringing the press to a stop. Substantially simultaneously with shifting of the pump to neutral, cam '13 closes switch I I 5 but reclosure of this switch does not cause the press to restart on its down stroke even though closure of switch H5 re-energizes relay solenoidl I1 and closes switches HI and I22. The reason why closure of switch I2I does not re-energize thrustor solenoid I29 is because palm switch I23 is presumed to be open and also switch Safety single cycle control.--If the operator fails to take his hands off of palm switch 423 during .retum movement of the platen, stll the press will not restart on its down stroke after returning to its upper position for the reason that switch H9 is connected to switch I23 and is open when'switch I23 is closed. Hence, so long as switch I I9 is openrelay solenoid II'I cannot be reenergized even though switchi II! is reclosed when the press returns to its upper position. Therefore, with solenoid II1 de-energized, the switch I2I cannot reclose and the circuit through the now assumed closed palm switch I23 is fully broken. Hence, energization of solenoid I" requires closure of both switches I I5 and II 9. However, if the operator removes his hand from palm switch I23, then switch II9 will close thereupon re-energizingrelay III to close switches I2I and I22. Thereupon the operator can reclose palm switch I23 to energize thruster solenoid I29 to start the next down cycle.

Position reversaL-A normally closed switch I33 is provided with a switch arm I34 adapted to be engaged by a cam 29' when the press platen reaches a predetermined lower position. Opening of switch I33 breaks the control circuit in the same manneras opening of the pressure responsive switch I3I. 'It will be understood that when pressure reversal is employed the positioning switch is maintained closed preferably by removing the position reversal cam. Conversely, when position reversal is employed the pressure reversal switch I3I is maintained closed preferably by closing the fluid pressure pipe thereto.

To obtain full automatic operation wherein the press moves up and down without stopping, it is only necessary to maintain a continuously closed circuit across switches I I 9 and I23, this being accomplished by the provision of by-pass circuits I35 and I35 both of which would be closed by manual switches I31 and I33. Circuit I 36 is also provided with a switch I39 which is closed by a solenoid I40, this solenoid being energized upon momentary closure of a manual switch I. Energization of this solenoid then closes a holding circuit I42. Switch I39 remains closed so long as there is no emergency stop of the' press. Hence, when the press moves to its upper position to close top limit switch I I5, a circuit is immediately established for energizing relay solenoid II'I thereby to close switch I2I which establishes a circuit for thrustor solenoid I29 to shift the pump to its forward pressing position. At the lower position of the press it is reversed in accordance with a predetermined condition of operation brought about either by position reversal or pressure reversal through switches I3I or I33. Hence, the press will move continuously up and down.

Emergency stopping and return of the press at any point during its pressing stroke during semi-automatic operation (one complete pressing and return cycle only) is accomplished merely by momentarily opening a switch I43 which thereupon breaks the circuit for relay solenoid III so that switches I2I and I22 open. The pump then is automatically shifted to its reverse po-v sition to move the press upwardly, the press coming to a stop at its uppermost position by action of cam 53 moving the pump to neutral. The press can then be restarted merely by closing palm button I23. During full automatic operation the same emergency switch can be employed.

However, to restart the press operation it is necessary to momentarily close switch I to re- 'energize solenoid I4II thereby to close-switch I39 and re-establish the by-pass circuit I35.

To stop the press in any desired position during the down stroke without having the press then move upwardly, it is only necessary to shift the pump to its 'neutral position, this being accomplished by closure of a switch I44 which closes a circuit I 45 for energizing a neutralizing thruster specifically shown herein for the purpose of illustration in the form of a solenoid I45. The solenoid I45 engages the lever of. bell crank I54: and is able to move the same upwardly only to its neutral position. To restart the cycle the switch I44 is opened thereby causing the weight of rod I and associated parts to shift the pump to its forward pressing position.

-Ope1'a1.ion--cam adjustments The present invention has particular reference gree of accuracy together with providing an ar .rangement that is sturdy and compact so that it may be installed in a remote control stand separate from the press structure per se if so desired. This adjustment can be eiiected either during operation of the press or while the same is at rest. To make such adjustments, for example to vary the position neutralizing cam 53, Fig. 2, and thereby determine the top position of the press platen, it is only necessary for theoperator to manually rotate knob 43 which rotates shaft 42, bevel gears 4 I, worm and worm gear 25 thereby causing a key 21, Fig. 2, to rotate sleeve II which in turn rotates cam disc I5 and accordingly angularly adjusts the position of neutralizing cam 53. Similarly, to adjust the position of slow draw stroke cam 55, as well as cam 55 which allows initial resilient reversal-of the press platen by virtue of a rubber pad or other means, the operator manually adjusts knob 40, Fig. '3, which, as shown in Figs. 2 to 4, rotates shaft 39, bevel gears 38, worm 33 and worm gear 24 thence through key 25 causing rotation of cam disc 23 and cams 55 and 59. The foregoing cam adjustments are indicated on the-face of front disc 29 by indexed dial discs 50 and 5I, Figs. 2 and 5, connected to the adjusting mechanisms for discs I8 and 23 through a small worm and worm gear shown in Fig. 4 at 45, 41 and at 45, 48. Suitable pointers 52, Fig. 5, have a normally fixed position with respect to disc 29 thereby to indicate the angular position on the dials 50 and 5| A position reversal cam 29', Fig. 2, may be remov ably bolted to disc .29 at any desired angular position thereon thereby determining the position at which the press platen is reversed. To allow for such adjustment a series of angularly spaced bolt holes I05, Fig. 4, may be placed around the disc circumference.

During operation of the press it will be understood that the-cam discs I9, 23 and 29 have a continuous back and forth movement, specifically an oscillating movement, in synchronism with movement of the press platen. During such oscillating movement it is possible for the operator to grasp handle or 43, rotate the same for adjusting the discs I5 and 23 thereby permitting the operator to observe the extent of platen movement and its immediate eflects in response to the cam adjustments. In this way no time is lost and all mechanical elements are in continuous operative relation without any need of making disconnections or other time consuming or expensive adjustments.

The eifectiveness'with which my improved cam mechanism is adapted to be brought into compact relationship to position reversal switch I33, top position switch H5 and switch I30 while allowing the operator to remove his hands from palm switch I33is seen in Fig. 5 wherein these switches are conveniently spaced around the disc 29.

Also brought into compact cooperative relationship to the cam operated crosshead 60, Fig. 2,

is my improved .pump volume control 8II5'I whereby the operator without changing his position with respect to the cam control mechanism may manually rotate handle 81, Fig. 2, thereby swinging arm 30 upwardly or downwardly to pro vide a limit stop for upward movement of crosshead 59 through engagement of lower portion 89 thereof with arm 80. The extent of upward movement of crosshead 60 determines the extent of eccentricity of the Hele-Shaw type of pump thereby controlling the rate of discharge or volume from the pump. Such volume control in turn determines the rate of movement of the press platen. In addition to this convenient volumetric control, I have also brought into cooperative control with the crosshead 60 but without interfering with the cam or volume controls a manual operating lever 12, Figs. 2 and 5, whereby by swinging lever 12 downwardly to position 12a the short arm 15 of the lever engages pin 16, Fig. 2, to raise crosshead 60 and thereby effect a pressing operation, whereas by moving lever 12 to position 12b, Fig. 5, the lever arm 15 permits the weight of crosshead 60 and rod l5 to move said elements downwardly thereby reversing the pump and sending the press platento its upper position.

From the foregoing disclosure it is seen that I have provided an extremely simple, effective and sturdy control mechanism having a high degree of flexibility of operation with maximum compactness and convenience, together with accuracy and sensitivity.

It will of course be understood that various changes in details of construction and arrangement of parts maybe made by those skilled in the art without departing from the spirit of the u invention as set forth in the appended claims.

I claim:

1. A control apparatus for a hydraulic press comprising, in combination, an oscillatable shaft, a plurality of cam discs-Journalled coaxially of said shaft to have oscillating movement therewith and each being independently adjustable relative thereto and to each other, a plurality of members arranged concentrically with respect to each other and to said shaft for adjusting said cam discs, and means whereby said plurality of concentric members oscillate at all times as a normal continuous part of the oscillation of said shaft.

2. The combination set forth in claim 1 further characterized in that said means includes a member rigidly connected to said shaft, operat ing members carried by said latter member in positions onset from the shaft axis, and gearing connecting said operating members with said concentric adjusting members.

3. The combination set forth in claim 1 further characterized in that said means includes a member fixed to said shaft, a plurality of operating elements journalled in said latter memher and offset from the axis of said shaft, worms carried by said member and adapted to be rotate'd respectively by said operating elements. and worm gears secured respectively tosaid concentric adjusting members whereby rotation of said worms effects adjustment of their respective cam discs.

4. A control apparatus for a hydraulic press comprising, in combination, a shaft, a plurality of cam discs iournalled coaxially of said shaft to have movementtherewith and each being adiustable relative thereto and to each other. means for effecting said adiustment'of the cam discs including actuating members disposed coaxially of said shaft, a member fixed to said shaft to move therewith at all times as a continuously normal part of the movement thereof, a plurality of operating elements journalled in said latter member and oflsetfrom the axis of said shaft. worms carried in said member and adapted to be at right angles to said worms thereby to indicate the angular position of said cam discs.

5. The combination set forth in claim 1 further characterized in'that said means includes a member fixed to said shaft, a plurality of operating elements journalled in said latter member in positions offset from the axis of said shaft,

worms carried by said member and adapted to be rotated respectively by said operating elements, worm gears secured respectively to said concentric adjusting members whereby rotation of said worms effects adjustment of their respective cam discs, and. means for oscillating said shaft whereby said cam discs and operating elements oscillate therewith.

6. A control mechanism for a hydraulic press having a movable member whose movement is under the control of hydraulically operated means for which fluid is supplied from a pressure fluid source comprising, in combination, means for variably controlling the pressure fluid for the hydraulically operated means, a shaft, a pair of axially spaced cam discs arranged coaxially of said shaft to be driven thereby, a crosshead for effecting actuation 'of said variable controlling means and being disposed between said discs and having ends extending in opposite directions from said shaft, means for reciprocably guiding said crosshead, and a pair of cam followers mounted on the opposite sides of said crosshead at one end thereof and a third cam follower mounted on one of said sides of the other end of said crosshead whereby the cam followers at opposite ends of said crosshead but on the same side thereof are both engageable by one of said cam discs to control successive portions'of movement of said crosshead in one direction of movement thereof and the other cam is engageable with said third cam follower to control movement of said crosshead in opposite direction of movement thereof thereby to effect a predetermined movement of said movable press member.

v 7. A control mechanism for a hydraulic press comprising, in combination, a press control member having a reciprocable crosshead, an oscillating shaft traversing the plane of reciprocation of said crosshead, a cam disc disposed coaxially of said shaft and driven thereby to move said crosshead in one direction, and means for controlling the extent of movement of said cross? head in a part of its movement including a pivoted arm engageable with said crosshead and a A screw and nut operatively connected to said arm to adjust the same.

8. A control mechanism for a hydraulic press comprising, in combination, a press control member having a reciprocable crosshead, an oscillating shaft traversing the plane of reciprocation of said crosshead. a cam disc disposed coaxially of said shaft and driven thereby to move said crosshead in one direction, said crosshead having a slot elongated in the direction of reciprocation, a pivotal arm extending into said slot to control the extent of movement of said crosshead in a part of its movement, and a screw and nut operatively connected to said am for adjusting the same. 7

' PAUL (J. OOH-INS.

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