US1980514A - Hydraulic press - Google Patents

Description

Nov. 13, 1934. w FERRls ET AL 1,980,514

HYDRAULIC PRESS Filed Aug. 50, 1929 5 Sheets-Sheet 1 I I I I I I I I l I I I I- I I I v I I I I WALTER FERRIs. GLEN MACOMBER.

Nov. 13, 1934.

w. FERRIS ET AL HYDRAULIC PRESS Filed Aug. 30, 1929 5 Sheets-Sheet 2 III/III] x gvwento'a! WAL TEIR FERRIs,

GLEN MAC ONBER.

Nov. 13,1934. .w. FERRIS ET AL HYDRAULI C PRES S 5 Sheets-Sheet 4 Filed Aug. 3Q, 1929 wow H n w I gwtwntow WALTER FERRIS- GLEN MACOMBER.

' I Patented Nov. 13, 1934 UNITED STATES- PATENT OFFICE HYDRAULIC PRESS Walter Ferris, Milwaukee, and Glen Macomber,

Waukesha, Wis., assignors to The Oilgear Comp'any, Milwaukee, Wis., a corporation of Wisconsin most of the jobs that they have to do. The stroke requirements vary withthe variety of work to be performed and the stroke must be long enough to accommodate the longest job. Besides this excess stroke a certain amount of clearance is necessary in the up stroke position to permit inspection, adjustment, and resetting of dies. In

a crank press .the operating stroke includes this clearance and is thus much longer than the working portion only of the stroke.

The present invention makes it possible to provide the required clearance without including it in the operating stroke, and also to adjust the length of working stroke to suit the work, so that the length of operating stroke is much less than that required in a crank press. Due to this reduced length of stroke it is possible to obtain a much greater number of strokes per unit of time without excessive linear die speed.

In the operation of draw presses it is customary to bring the dies hard together at the lower dead point to eifect a desired finish on the work. In crank presses it is impossible to determine that pressure with any degree of accuracy, and very diflicult to maintain it constant. This is due to variations in the thickness of the metal to be stamped and to variations in the die spacing caused by changing temperatures in the press frame, etc. In fact press breakage is commonly theresult of the accidental feeding of two blanks at once between the dies or by lodgment of scrap material therebetween.

Another object of the present invention is to eliminate the difliculties above mentioned by permitting the ram to stall under a. predetermined hydraulic pressure at the end of each draw stroke. A

Other more specific objects and advantages of the present invention will appear from the following description of an illustrative embodiment thereof. V

In the accompanying drawings:- a

Fig. 1 is a front elevation, partly in section, of a press embodying the present invention.

Fig. 2 is an elevation of the left side of the press.

Fig. 3 is a top plan.

Fig. 4 is a fragmentary elevation of the right ide of the press illustrating the controls therefor. Fig. 5 ma diagrammatic illustration of the hydraulic drive system employed.

Figs. 6 and 7 are sectional views of the reversing valve shown in Fig.5, illustrating two additional characteristic positions thereof.

Fig. 8 is a sectional view of the pilot valve with its control mechanism, shown in Fig. 5, illustrating a second position thereof.

Fig. 9 is a sectional view of another valve shown in Fig. 5, illustrating a second positionthereof.

The press shown in Figs. 1 to 4 comprises a bed 10, supported on an appropriate base 11, and a pair of standards 12 which rise from the base at opposite sides of the bed and support an appropriate head casting 13. A ram 14, guided by and between the standards, is supported by a pair of pull-back cylinders. 15 seated and securely anchored in the head 13.- Pistons 16, reciprocable in the cylinders 15, are connected to the ram through suitable piston rods 17. The lower ends of both cylinders are supplied with liquid through a manifold pipe 18 in a manner to be later described. The ram 14 carries a plunger 19 which projects upwardly to and coacts with a press cylinder 20 whichgakalso anchored in the head 13. This cylinder is' upplied with liquid through a pipe 21 in a manner to be later described. 1

A shaft 22, journaled in appropriate bearings 23 on the head 13 of the press, is driven through a gear 24 and pinion 25 from a shaft 26, also supported by the head 13, and which is driven through a gear 27 and pinion 28 from an electric motor 29. The motor is mounted on a suitable bracket carried by the head 13. An adjustable throw crank 30 is carried by one end of the shaft 22. In this instance the crank 30 projects eccentrically from a split clamp-ring or collar 31 adjustably fixed to an eccentric 32 carried by the shaft. By rotative adjustment of the collar 31 upon the eccentric 32 the throw of the crank 30 may be regulated in a well known manner. A bifurcated link 34 provides a driving connection between the crank 30 anda double ended impeller plunger. 35. In this instance the link is pro- 'vided with a circular head 36 at the upper end thereof, journaled upon the crank .30, while the lower legs 37 thereof are provided with circular heads 38 journaled respectively upon the opposite ends of a cross pin 39in the plunger. The opposite ends of the plunger are guided and reciprocate in opposed cylinders 40 and 41 secured to one v of the standards 12 of the press frame. Pipes 42 and 43 from the cylinders lead to a valve 44.. The arrangement is such that as the shaft 22 is rotated the plunger 35 is reciprocated through a distance dependent upon the throw of the crank 30, to thereby cause liquid to flow back and forth through the pipes 42 and 43.

The valve 44 is shown in detail in Figs. 5, Band 7. It comprises a block 45 having a longitudinal bore therein with a valve plunger having four longitudinally spaced heads 46, 47, 48, and 49 closely fitted for reciprocation in the bore. An annular groove 50 in the bore, adjacent the head 46, communicates with a similar groove 50, adjacent the head 49, through a passage 51 in the block. Passage 51 communicates with the manifold pipe 18 leading to the lower ends of the pull-back cylinders 15. A similar groove 52, between the heads 46 and 47 communicates with the pipe 42. Another groove 53, between heads 46 and 47, communicates with a groove 53, be-

tween the heads 48 and 49, through a passage 54 which communicates with the pipe 21 leading to the press cylinder 20. Another groove 55 beand 43 from the impeller cylinders 40 and 41 communicate with each other through the grooves 52 and 53, passage 54, and grooves 53' and 55 so that there is an idle flow of liquid back and forth through those pipes during reciprocation of the impeller plunger 35. It will also be noted that, with the valve plunger in this neutral position, both grooves '50 and 50' are covered by the heads 46 and 49, respectively, so that the passage 51 isblocked and the ram 14 is supported by the column of liquid thus confined in the pipe 18 and in the lower ends of cylinders 15. A

Whenever the plunger of valve 44 assumes the upper position of Fig. 6, pipe 42 then communicates with manifold pipe 18 through the grooves .52 and 50 andpassage 51, and pipe 43 communicates with pipe 21 through grooves 55 and 53' and passage 54. The upper impeller cylinder 40 is thus connected with'the press cylinder 20 and the lower impeller cylinder 41 is connected with the lower ends of the pull-back cylinders 15, so that on each upstroke of the impeller plunger 35 the ram 14 is driven downwardly and uponeach down stroke of the impeller plunger the ram is driven upwardly. The length of ram stroke is of course dependent upon the length of stroke of the plunger 35.which is regulated conditions are reversed, the upper impeller cyl-- inder 40 being connected to the pull-back cylinders 15 through the pipe 43, grooves 55 and 50',

passage 51, and pipe 18, and the lower impeller cylinder 41 being connected to the press cylinder 20 through the pipe 42, grooves 52 and 53, passage 54, and pipe 21, so that the ram then travels downwardly during each down stroke of the impeller plunger 35 and upwardly during the upward stroke of the impeller plunger.

lower end of its stroke, the ram 14 will be forced I downwardly on a working stroke during the next up stroke of the impeller plunger; and that by shifting the valve plunger into the lower position of Fig. 7, while the impeller plunger 35- is at the upper end of its stroke, the ram 14 will be forced downwardly on a working stroke during the next down stroke of the impeller plunger. The ram 14 may thus be made to execute a working stroke during either the up or down stroke of the impeller plunger by'shifting the valve plunger at the proper time and in the proper direction from neutral position. It will also be noted that in order to complete the valve plunger is promptly returned into its neutral position of Fig. 5 immediately upon the return of the ram 14 to its upper position,,which occurs as the impeller plunger 35 returns to the end stroke position it had assumed when the valve plunger was originally shifted. In the press shown the valve 44 is actuated and controlled by mechanism which, upon operation of a control element, will eil'ect the automatic shifting of the valve plunger at such time and in such direction, as to effect a down stroke of the ram 14 during the following stroke of the impeller plunger (either up or down) and to hold the valve plunger in that position until the ram has completed its operating cycle by returning to its upper position or until any desired number of such cycles have been completed.

Mechanism for this purpose includesan auxiliary impeller cylinder 60 mounted upon one of the press standards 12 and containing a piston '61 whichis reciprocated synchronously withv the main impeller plunger 35. The piston 61 is shown connected through a rod 62 and link 63 with a crank 64 on arm 65 adjustably fixed to a disk 66 journaled on a stub shaft 67 in the head 13 of the press; The arm 65 is rotatably supportedon the end of the stub shaft 67 and is provided with an arcuate slot 68 for receiving a clamp screw 69 threaded into one of a series of sockets 70 in the face of the disk 66. The disk 66 is driven at the same speed as shaft 22 through a sprocket chain 71 whichpasses around a sprocket wheel 72 fixed on shaft 22 and around the toothed periphery of the disk 66. The throw of the crank 64 is non-adjustable but upon releasingthe clamp screw 69 the crank angle of arm 65 may be adjusted to parallel the crank angle of the crank 30in all positions of adjustment thereof, or to any desired angle in advance of said crank angle, so that the proper phase relation between piston 61 and plunger 35 may be maintained.

A pipe 73 connectedwith the cylinder 60 at opposite sides of the piston 61 forms a by-pass around the piston throughout an intermediate portion of the piston stroke, the by-pass being suddenly blocked by the piston as it approaches either end of its stroke. Two pipes 74 and 75 lead from the opposite ends of the cylinder to a control valve 82 to be later described. .The cylinder 60 and, pipes 73, 74 and 75 are maintained flooded with liquid at low pressure supplied from an appropriate pressure source such as a gear pump 81. In this instance a pipe 79 leading from the gear pump 81 communicates with two branch pipes 76 and 78 which lead to the ' pipes 74 and 75, respectively. Check -valves 77 and 80 in the branch pipes 76 and 7-8 prevent the escape of liquid from pipes '74 or '75 back to thegear pump. During reciprocation of the piston 61 in synchronism with the impeller plunger 35 liquid flows freely in one direction or the other through the pipe '73 during the intermediate portion of the piston stroke, but each time the piston approaches an end of its stroke, and thus covers an end of the pipe '73, the pipe '73 is suddenly blocked and thereafter liquid is forcibly ejected through pipe '74 or '75. The liquid thus suddenly forced through pipe '74 or is utilized to shift the plunger of valve 44 up or down into the position of Fig. 6 or Fig. '7. This action is controlled by a control valve 82 such as will now be described.

The control valve 82 is mounted on one of the press standards 12, as indicated in Fig. 1.. It is shown in detail in Figs. 5 and 8. It comprises a substantially cylindrical block having a longitudinal bore containing a valve plunger having five spaced heads 83, 84, 85, 86 .and 8'7. Two spaced annular grooves 88 and 89' within the bore between the heads and 86 communicate with the pipes '74 and 75, respectively, from the upper and lower ends of the cylinder 60. (See Fig. 5). A groove 90 controlled by the head 85 communicates with a pipe 91 which leads to the upper end chamber 92 of the bore in the valve 44. Another groove 93 below the head 86 communicates with a pipe 94 which leads to the lower end chamber 95 of the bore of valve 44. Pipes 91 and 94 enter the end chambers 92 and 95 immediately above and below the intermediate positions of the upper and lower end heads 46 and 49, respectively, of the valve plunger, so that when the valve plunger is elevated, as in Fig. 6, pipe 91 is blocked lowered, as in Fig. '7, pipe 94 is blocked by the head 49. A branch pipe 96 controlled by a check valve 97 permits the escape of liquid from end chamber 92 into ppe 91 when that pipe is thus blocked by head 46; and a branch pipe 98 controlled by a check valve 99 permits the escape of liquid from end chamber 95 into pipe 94 when that pipe is thus blocked by head 49.

A groove 100 in the bore of valve 82 below the groove 93 is open to a pipe 101, a groove 102 in the bore below the head 84 is open to a drain pipe 103 which communicates with a drain pipe 104 through an enlarged chamber 104' in the lower end of the bore. An annular groove 105, con trolled by the head 84 of the valve plunger, communicates through a pipe 106 with an appropriate fiuid pressure source such as a pump 107 hereinafter described. A spring loaded pressure accumulator 108 of a well known type is preferably connected with the pipe 106 in order to promptly supply the sudden liquid demands made upon this pipe. Another groove 109, between groove and the head 83, communicates through a pipe 110 with a pair of branch pipes 111 leading to the outer ends of push cylinders 112 and 113, respectively, disposed adjacent the end chambers 92 and 95. A lower groove 109' also communicates with branch pipes 111 through a pipe 110'.

Pistons 114 and 115 in cylinders 112 and 113 carry push pins 116 and 117 which, when fully advanced, bear against the end heads 46 and 49 to thereby center and retain the valve plunger in the neutral position of Fig. 5.

The upper end of the bore of the pilot valve 82 is connected through a pipe 118 with the dis charge ends of two spring loaded relief valves 119 and 120, the intake side of valve 119 being connected to a pipe 121 which enters the bore of valve 44 at a point below the pipe 91, the intake side of valve 120 being connected to a pipe 122 which enters the bore of valve 44 at a point above the pipe 94. The arrangement is such that both pipes 121 and 122 are blocked by the heads 46 and 49 when the plunger of that valve is in the neutral position of Fig. 5; that-pipe 122 is open to the lower end chamber 95 when the valve plunger is in the upper position of Fig. 6; and that the pipe 121 is open to the upper end chamber 92 when the. valve plunger is in the lower position of Fig. '7.

The plunger of pilot valve 82 may assume either of two positions, namely:the lower position of Fig. 5 or the upper position of Fig. 8. It is provided with a control'stem 123 having a groove 124 for receiving a spring loaded detent 125 by which it is yieldably held in the lower position and a second groove 126 for coaction with the detent 125 by which it is yieldably retained in the upper position. When in the lower position of Fig. 5 the pipes '74 and 75 communicate through the grooves 88 and 89 so, that the auxiliary impeller circuit is by-passed and the piston 61 is reciprocating idly. Grooves 105 and 109 also communicate with each other so that both of the push cylinders 112 and 113 of the valve 44 are exposed to the pressure in pipe 106 through pipe 110 and branch pipes 111. The plunger of valve 44 is thus held in the neutral position of Fig. 5 so that the main impeller circuit, including the pipes 42 and 43, is also by-passed in the manner here-' inabove explained.

When the plunger of valve 82 is in the elevated position of Fig. 8, pipe 110 is blocked and pipe 110' is open to the drain pipe 103 so that the pressure in the push cylinders 112 and 113 is destroyed; the pipe 101 is blocked by the head 8'7 groove 89 is open to groove 93 and groove 88 is open to groove 90, so that the lower end of the auxiliary impeller cylinder 60 is connected to the lower end chamber 95 through pipes '75 and 94 and the upper end of cylinder 60 is connected to the upper end chamber 92 through pipes '74 and 91. It will thus be noted that if this valve plunger is thus elevated during the up stroke of the impeller piston 61, that piston, after covering the upper end of pipe '73, will suddenly induce a flow of liquid through pipes '74 and 91 into the upper end chamber 92 to thereby force the plunger of valve 44 downwardly into the position of Fig. '7

and thereby connect the press cylinder 20 with the lower impeller cylinder 41 through pipes 21 and 42 and connect the pull-back cylinders 15 with the upper impeller cylinder 40 .through the pipes 18 and 43. These connections are thus established'as the auxiliary piston 61 and the main impeller plunger 35 approach their upstroke position, so that on the next down stroke of the plunger 35 the ram 14 is driven downwardly by I it and in step with it. It will also be noted that if the plunger of valve 82 is thus elevated during a down stroke of piston 61, that piston, after covering the lower end of the pipe '73, will suddenly induce a flow of liquid through pipes '75 and 94 into the lower end chamber 95 to thereby force the plunger of valve 44 upwardly into the position of Fig. 6 and thereby connect the press cylinder 20 with the upper impeller cylinder 40 through pipes 21 and 43 and connect the pull-back cylinders 15' with the lower impeller cylinder 41 through the pipes 18 and 42., ince these connections are thus establishedas piston 61 and plunger 35 reach the lower ends of their strokes,

' the ram 14 is driven downwardly by the plunger During upward movement of the plunger of valve 44 under the pressure in pipe 94 and chamher 95, liquid is free to escape through the pipe 96 and check valve 97 even after the end of pipe 91 has been covered by the head 46in its upward advance. Similarly during downward movement of this valve plunger under the pressure in pipe 91 and chamber 92 liquid is free to escape through the pipe 98 and check valve 99 after the end of pipe 94 has been blocked by the head 49. The plunger of valve. 44 remains in either'the upper or lower position into which it has been shifted until the plunger of valve 82 is returned into the lower position of Fig.. 5, which, as will hereinafter appear, can occur only at the end of a complete two stroke cycle of the plunger 35, piston 61, and ram 14, or in other words until the ram 14 reaches an up-stroke position. This is true in spiteof the periodic reversal of flow in the pipes 74 and 75 as the piston 61 travels up and down. This is due to the fact that if the plunger of valve 44 was raised into the position of Fig. 6 by the pressure in the chamber 95 and pipes 75 and 94 during the down stroke of the piston 61, the pipe 91 is then blocked by the head '46 and no liquid can enter the upper chamber 92 through this pipe or through the check valve 97 by the pressure produced in pipes 74 and 91 during an up-stroke of the piston. Likewise if the. valve plunger was lowered into the position of Fig. 7 during the up-stroke of the piston 61, liquid cannot enter the lower chamber 95 through the pipe '94 or check valve 99 during a down stroke of the piston. When the plunger of valve 82 is. returned however into the lower position of Fig. 5 the auxiliary impeller circuit is again bypassed through the grooves 88 and 89. the upper chamber 92 is again opened to drain pipe 103.

through pipes 96 and 91 and grooves 90 and 102, and the lower chamber 95 is opened to the drain pipe 104 through the pipes 98 and 94 and grooves 93 and 104'. Also both push pistons 114 and 115 are exposed to the pressure in pipe 106 through grooves 105 and 109 and pipes 110 and 111, so that both push pins 116 and 117 are advanced to return ancl'center the plunger of valve 44 into the neutral position of Fig. 5. This of course bypasses the main impeller circuit and stops the ram 14. as hereinabove described.

In the machine shown the plunger of valve 82 is mechanically elevated by a cam 127 and hydraulically depressedby liquid suppliedto the upper end thereof through pipe 118. The cam 127 .is rotatably supported on a stub shaft 128 anchored in a boss-129 projecting from one of the press uprights 12, and is provided with four symmetrically arranged, flat topped lobes 130 with intermediate low portions 131 which coact with a cam roller 132 on the end of the valve stem 123. The cam is intermittently rotated through successive angles of 45 degrees, by mechanism to be later described, to lift and supportthe valve plunger in the upper position of Fig. 8 or to permitlowering of the valve plunger into the position of Fig. 5. This plunger may thus be lifted at any time during either any up stroke or down stroke respectively of the impeller plunger 35, but the valve 44 is not operated to connect pipes 42 and 43 with pipes 18 and21 until completion of said up or down stroke during which the'plunger of valve 82 was lifted, and the hydraulie system does not function to return the plunger to; its lower position until the connection of pipes 18 and 21 with pipes 42 and 43 has been maintained during one or more full revolutions of the crank 30.

The functioning of the hydraulic system for this purpose will now be described it being understood that the plunger of valve 82 is elevated by rotation of the cam 127 and is supported in this position by the lobe 130 that has thus been positioned below the roller 132, as indicated in Fig. 8. If it is thus elevated during an up stroke of the plunger 35;and piston 61, the plunger of valve 44 is of course lowered by liquid supplied to end chamber 92 through- pipes 74 and 91 from the cylinder 60, as the piston 61 approaches the upper end of its stroke, as hereinabove described.

The volume of liquid thus supplied through pipes 74 and 91 however is considerably in excess of that required to thus lower that valve plunger, and the excess escapes through the pipe 121, which has been uncovered by the head 46, passes through the relief valve 119, and thence through pipe 118 into the upper end of the bore of valve 82. As long as the lobe 130 of the cam is in the position of Fig; 8 it keeps the plunger of valve 82 from lowering, and this excess liquid finds its way through pipe 133- and relief valve 134 to the drain pipe 103. Then, on the succeeding down stroke of the plunger and piston 61, the ram 14 is driven downwardly in the manner previously' described, and although the piston 61 as it approaches the lower end of its stroke ejects liquid through pipe '75, this liquid cannot affect the posi ion of the plunger of valve 44 because the head 49 thereof blocks pipe 94, and pipe 98 is blocked by check valve 99, so the plunger of valve 44 remains in the lower position of Fig. 7, and as the plunger 35 and piston 61 start upwardly, the ram 14 begins its return stroke. cam 127 is rotated so as to position a low portion 131 thereof beneath the roller 132, at any time 1 after the ram 14 has started down and before it If the 91 to-chamber 92 and then through pipe --121, M

check valve 119 and pipe 118. The plunger of valve 82 then returns to the lower position of Fig. 5, and the plunger of valve 44 returns to neutral in the manner hereinabove described and the ram 14 comes to rest'in its up-stroke position.

If the plunger of valve 82 happens to be elevated by rotation'of cam 127 into'the position of Fig. 8, during a down stroke of the plunger 35 and piston 61, liquid discharged through pipe 75 into chamber 95, atthe end of the down stroke, first elevates the plunger of valve 44 into the position of Fig. 6 and the excesspasses through pipe 122, check valve and pipe 118 and attempts to force that valve-plunger down. Again the upright lobe 130 of the cam holds the valve plunger in its elevated position against this .momentary hydraulic thrust, and the plunger If at any time before the ram 14 reaches 7 the end of its return stroke the cam 127- is again rotated to position one of the low portions 131 after one complete ram cycle. "This mechanism draulicthrust produced as the piston 61 again approaches-the lower end of its stroke and thus forces liquid through pipes 75, 94 and 122, check valve 120 and pipe 118.

It will thus be noted that whenever the cam 127 is rotated into the position of Fig. 8 so as to elevate the plunger of valve 82 (whether during an up or down stroke of the plunger and piston 61) the plunger of valve 44 will automatically shift (either down or up) at the instant of the next reversal of movement of the plunger 35 and piston 61, so as to cause the ram 14 to first move down and then up in synchronism with the plunger 35; that the ram 14 will thus continue to reciprocate until the cam 127 is again rotated so as to position a low portion 131 thereof be low the roller 132; and that thereafter the ram 14 will always come to rest in its up-stroke position.

It will also be noted that when the plunger of valve 44 is in the neutral position of Fig. 5 grooves 56 and 57 thereof communicate, so that the pipe 118 is then open through pipe 58 to the drain pipe 59 and liquid can escape freely from the upper end of the bore of valve 82 so there is no hydraulic resistance to the elevation of this valve plunger. However, when the plunger of valve 44 is in either the upper position of Fig. 6 or the lower position of Fig. 7, pipe 58 is dead ended so that when pipe 118 receives a charge of liquid through either of the relief valves 119 and 120 that liquid cannot escape except through the relief valve 134 whose setting thus determines the degree of pressure available to force down the plunger of valve 82.

The cam 127 is in this instance placed under the control of an attendant through mechanism which will now be described, reference being made to Figs. 4, 5. and 8. The cam is formed integral with an eight toothed ratchet wheel 135. A disk 136 rotatable on the shaft 128, adjacent the ratchet wheel, carries a clamp screw 137 which may be advanced into engagement with is yieldably held in the upper position of Figs.

4 and 5 by a suitable spring 141. A stop screw 142 limits the throw of the pedal.

The arrangement is such that with the clamp screw 137 released a step-by-step rotation is imparted to the cam'by successive depressions of the pedal soas to position the lobes 130 and 7 low portions 131 of the cam below the roller 132,

successively. A depression of the pedal will thus elevate the plunger of theyalve 82 to thereby start the press, and the ram 14 will continue to reciprocate until the pedal is again depressed, after which the valve plunger will automatically return to its lower position to stop the ramwhen the ram next reaches its up-stroke position.

With the clamp screw 137 applied to the wheel the plunger of valve 82 is elevated to start the press whenever the pedal is depressed and the press continues to operate until the pedal. is released and until the ram 14 thereafter returns to its up-stroke position.

The control mechanism shown also includes mechanism for automatically stopping the press valves or by ordinary leaka comprises an arm 143' rockably supported on the shaft 128 and carrying a second pawl 144 which coacts with the ratchet wheel 135. A

piston 145 in a cylinder 146 is connected to the arm 143 through appropriate linkage 147. A

spring 148 yieldably retains the piston 145 in ing from the rear end of the cylinder 146 connects with the pipe 118. An appropriate cutoff valve 150 in the pipe 149 may be closed to render the piston 145 inactive but when this valve is open and the clamp screw 137 is released this control mechanism functions in the following manner. Depression of the pedal 139 efiects rotation of cam 127 so as to lift the plunger of valve 82 to start the press. Then as the ram 14 approaches its up-stroke position the piston 61 is of course approaching an end of its stroke so as to suddenly subject the upper end of the valve 82 to hydraulic pressure through pipe 118. This pressure is simultaneously transmitted through pipe 149 to cylinder 146 to thereby advance .the piston 145. and rotate the cam so as to permit the valve plunger to go down and High pressure relief valves 151 and 152 connected with the pipes'74 and 75, respectively, and arranged to discharge into the drain pipe 103, protect the auxiliary impeller circuit against excessive'pressures. These valves, are set to resist considerably higher pressures than either of the valves 119 and 120, or the valve 134. Any liquid escaping from the circuit either through these is promptly replaced by liquid supplied from the gear pump 81 through pipe. 79, check valve 77 or 80, and pipe 73.

Also two high pressure reversely arranged relief valves 153 and 154 connected across pipes 42 and 43 protect the main circuit against excessive pressures. Any liquid escaping from the main circuit is promptly replaced by liquid supplied from the.

gear pump 81 through pipes 79 and 155 and check valves 156 and 157 connected to the pipes 18 and 21, respectively. The gear pump 81 is enclosed within the casing of the pump 107 and receives its supply from a reservoir 158 in the base of that casing. A low pressure relief valve 159 connected to pipe 79 and arranged to discharge into the reservoir 158 determines the pressure within the pipe 79 and parts connectedtherewith.

The drain pipes 103 and 104 connect with the drain pipe 59. which leads back to the reservoir 158. A drain pipe 160 connecting the inner ends of the push cylinders 112 and 113 also communicates with the drain pipe 59, through the cylinder 113 so that the liquid therein also escapes back to the reservoir 158. A manifold pipe 161 connected with the upper ends of the pull-back cylinders through pipes 160 and 59.

During normal operation of the press the stroke of the ram 14 is ordinarily only slightly greater than'is necessary to completethe required draw portion of the stroke between the upper and lower dies 162 and 163 and to provide clearance for removing the finished work and for feeding fresh work therebetween. This stroke is adjusted to suit the particular job by adjusting the throw of the crank 30 in the manner hereinabove explained} However in order to provide suflicient clearance between the dies for purposes of in- -15 also communicates with the reservoin 158'- spection, resetting or replacement, provision is made for elevating and lowering the range of re- 1926. It is a multiple piston, variable displacement pump which is ordinarily driven at constant speed through a pulley 164 and whose displacementis varied from zero to a maximum by adjustment of a rock arm 165. It discharges through a pipe 166, which in this instance communicates with branch pipes 106 and 1 68, and it receives liquid through a pipe 169. A compression spring 170 acting against the end of arm 165 urges this arm toward maximum displacement position. The spring 170 is opposed by a piston 171 in a cylinder 172, the cylinder being connected to the pipe 106 so that the pressure in discharge pipe 166 urges the arm 165 toward zero stroke position. The displacement of this pump is thus automatically reduced by increased discharge pressure. A high pressure relief valve 173 protects the pump against excessive pressures. In this instance the pipe 106 leads to the groove 105 of valve 82 to return the plunger of valve 44 to the neutral position of Fig. 5 when the plunger of valve 82 is lowered, as hereinabove explained. The other branch pipe 168 and the return pipe 169 are interchangeably connected to pipes 21 and 18, respectively, through pipes 174 and 1'75 and a valve 176 which will now be described.

The valve 176 is shown in detail in Fig se5 and 9. It comprises a casing having two aligned bores 177 and 178 separated by an intermediate partition 179. A plunger having three heads 180, 181

and 182 is closely fitted for reciprocation inbore 177 and is connected through a stem 183 with a double headed plunger 184 in bore 178. A spring 185 in the left end of bore 177 yieldably retains both plungers in the right extreme position of Fig. 5 A groove 186 controlled by head 180 and a groove 187 controlled by head 182 are both connected to the pipe 175. Spaced grooves 188 and 189, both controlled by head 181, are connected through a pipe 190 with a groove 191, controlled by plunger 184. A second groove 192 controlled .by plunger 184 is connected with the pipe 174.

A check valve 193 permits liquid to flow from pipe 190 into pipe 174. A groove 194 between the head 180 and groove 188 is connected by a pipe 210 with pipe 169, and a groove 195 controlled by head 181 is connected with pipe 168. The right end of bore 177 is connected through a pipe 196 with the pipe 101. .Both ends of the bore 178, as

well as the left end of bore 177, are connected,

and 169 back-to the pump 107. This of course 'causes the ram 14 to rise. With the valve 176 in the left extreme position of Fig. 9 the pump discharges through pipes 166 and 168, grooves 195 and 189, pipe 190, check valve 193, and pipes 174 and 21 to cylinder 20, liquid returning from the pull-back cylinders 15 through pipes 18 and 175, grooves 186 and 194, pipe 210 and pipe' 169 back to the pump 107. This, of course, causes the ram 14 to move downwardly. The safety relief valve 210 allows liquid to escape through it into the drain pipe 59 in case the pressure in the pull back cylinder 15 becomes too high. The plungers of valve 176 are yieldably retained by the spring 185 in the right extreme position of Fig. 5, a position assumed while the press is idle, or, in other words, while the plunger of valve 82 is down and the plunger of valve 44 is in neutral. The plunger of valve 176 is aut0- matically shifted however into the left extreme position of Fig. 9, by liquid pressure supplied through pipe 196 whenever the plunger of valve 44 assumes either the upper position of Fig.6 or the ,lower position of Fig. 7, oi, in other words, whenever the press is rendered active. The hydraulic operation of valve 176 is accomplished in the following manner. Two branch pipes 198 and 199leading from the end chambers 92 and 95 of the valve 44, respectively, are connected to the pipe 101 through individual check valves 200 and 201, so that liquid may escape from either of,

circuit, as hereinabove explained, and the pipe 101 is exposed to and sustains the pressure thus established in one or both of these end chambers.

'to the opposite sides of the auxiliary impeller (It will be remembered that a pressure is always I maintained in the auxiliary impeller circuit by thegear pump 81 and pipe 79.) The pressure thus established in pipe 101 when the plunger of valve 82 is elevated is transmitted through pipe 196 into the right end of the bore 177 of valve 176 to thereby shift the plungers thereof into the left extreme position of Fig. 9.

The pipe 168 contains a valve 202 for regulating the rate of flow through the pipe 168, this valve being in the form of an ordinary cock having an operating lever 203. A spring 204 connected with 9. lug 205 acts upon the lever 203 to open the valve, and an adjustable stop screw 206 in the lug 205 limits this opening. The lever 203 projects into the path of movement of a stop 207 .adjustably fixed by a set screw 208 to a rod 209 which is anchored to and depends from the ram 14. The spring 204; serves to yieldably retain.

the valve 202 in a partially open condition, as determined by the screw 206, so long as theram 14' is in a lower position, but as the ram 14 moves upwardly under the action of the liquid suppl ed through pipes 168, 175, and 18, the stop 207 ultimately engages the lever 203 and gradually closes the valve 202 so as to gradually reduce the'fiow through pipe 168 and thus terminate this upward movement of the ram. ,This upward travel of the ram 14 occurs when the valve 176 is held by the spring 185 in the right extreme position of Fig.

5, a position assum d when the press ram isidle.

3. In a hydraulic press the combination of a shown in Fig. 9 so that the pump 107 then delivers liquid into the cylinder 20 and the ram 14 moves downwardly, the valve 202 being opened by the spring 204 on the initial down stroke of the ram 14 under the action of the impeller plunger 35. The ram 14 then continues to reciprocate, under the action of plunger. 35, and also continues to travel downwardly under the action of the pump 107, so that the range of reciprocation of the die 162 approaches the die 163. This continues at a rate determined by the setting of the stop screw 206, which controls the amount of opening of the valve 202, until the upper die 162 actually stalls against the lower die 163 on each down stroke thereof. Each time that the upper die 162 thus stalls against the lower die, a small amount of liquid escapes from the main impeller circuit through one or, the other of the relief valves 153 or 154 which thus determine the pressure exerted upon the work on each down stroke of the upper die. The pump 107 continues to supply additional liquid to the,

cylinder to cause the upper die to continue to stall against the lower die as the reciprocation continues. Then when the plunger of valve 82 is lowered to stop the press, the plungers of valve 176 return to the right extreme position of Fig.- 5 and the ram 14 moves upwardly under the action of liquid supplied to the pull-back cylinders 15 from the pump 107, until the valve 202 is again closed by the action of the stop 207 upon the valve lever 203.

It will be noted that the upper idle position of the ram 14 is thus determined by the position of the stop 207 upon the rod 209, so that this vertical travel of the ram may actually be eliminated by proper adjustment of the stop 207 on the rod 209. Thus for work that requires only one ram reciprocation the stop 207 may be set to close the valve 202 upon each return stroke of the ram, so that upon each down stroke of the ram 14 the ram will start from such position that the upper die will stall against the lower die at the end of each down stroke thereof.

Various changes may be made in the embodiment of the invention hereinabove specifically described without departing from or sacrificing any of the advantages of the invention as defined in the appended claims.

We claim:-

1. In a hydraulic press the combination of a ram, hydraulically actuated means for driving said ram, a reciprocating hydraulic impeller, channel connections between said means and impeller through which said ram is driven in one direction by movement of saidimpeller in one direction, other channel connections between said means and impeller through which said ram is reversely driven by reverse movement of said impeller, and valve means for modifying said connections to reverse the movement of said ram relative to that of said impeller.

2. In a hydraulic press the combination of a press ram, hydraulically actuated means for reciprocating said ram, a reciprocating hydraulic impeller, hydraulic connections between said impeller and means through which said ram may be reciprocated synchronously by and with said impeller, said connections including a fluid actuated valve for rendering said rain active or inactive, an auxiliary impeller reciprocated in unison with the aforesaid impeller for delivering liquid to said valve to operate the same, and a valve.

press ram, hydraulically actuated means for reciprocating said ram, a reciprocatingv hydraulic impeller, hydraulic connections between said impeller and means through which said ram may be reciprocated synchronously by and with said impeller, said connections including a-valve operable to render said ram active or inactive, and fluid pressure means for shifting said valve into and out of active position, said fluid pressure means being effective only at an end of a stroke oi said impeller.

4. In a hydraulic press the combination of a press ram, hydraulically actuated means for reciprocating said ram, a reciprocating hydraulic impeller, hydraulic connections between said impeller and means through whichsaid ram may be reciprocated synchronously by and with said impeller, said connections including a valve operable to cause said ram to efiect first a working stroke and then a return stroke irrespective of the direction of motion of said impeller, and means for shifting said valve into and out of active position, said last named means being effective only at an end of a strokeof said impeller.

5. In a hydraulic press the combination of a press ram, hydraulically actuated means for reciprocating said ram, a reciprocating hydraulic impeller, hydraulic connections between said impeller and means through which said ram may be reciprocated synchronously by and with said impeller, said connectionsincluding a hydraulically actuated valve for controlling said ram, and an auxiliary hydraulic impeller reciprocating synchronously with said first named impeller for operating said valve.

'6. In a hydraulic press the combination of a press ram, hydraulically actuated means for reciprocating said ram, a reciprocating hydraulic impeller, hydraulic connections between said impeller and'means through which said ram may be reciprocated synchronously by and with said impeller, said connections including a hydraulically actuated valve, an auxiliaryhydraulic impeller for operating said valve, and a second valve between said auxiliary impeller and said first named valve for controlling said first named valve.

7. In a hydraulic press the combination of -a' press ram, hydraulically actuated means for reciprocating said ram, a reciprocating hydraulic impeller, hydraulic connections between said impeller and means through which said ram may be reciprocated synchronously by and with said impeller, said connections including a hydraulically actuated valve for controlling said ram, an auxiliary impeller reciprocating synchronously with said first named impeller for operating said .valve, a second valve for controlling said first named valve, means for shifting said second valve in one direction to start said ram, and means responsive to a predetermined increase in fluid IOU pressure for shifting said second valve in another y direction to stop said ram.

8. In a hydraulic press the combination of a reciprocatinghydraulic impeller, a hydraulically actuated ram, hydraulic connections through 9. In a hydraulic press the combination of a reciprocating hydraulic impeller, a hydraulically actuated ram, hydraulic connections energized by and with said impeller for actuating said ram synchronously therewith, means including a valve for controlling said ram, an element for controlling said valve, means under the control of the operator and operable on said element tostart said ram, and hydraulically actuated means operable on said element to stop said ram.

10. In a hydraulic press the combination of reciprocating hydraulic impeller, ,a hydraulically actuated ram reciprocated synchronously by and with said impeller, means including a valvefor controlling said ram, a rotary element for controlling said valve, a control lever, ratchet mechanism between said lever and element to normally effect a step-by-step rotation of said element by rocking said lever, and means for rendering said ratchet mechanism ineffective to thereby efiect oscillation of said element by rocking said lever.

11. In a hydraulic press the combination of a reciprocating hydraulic impeller, a hydraulically actuated ram reciprocated synchronously by and with said impeller, means for advancing and retracting the range of reciprocation of said ram, means for starting the reciprocation of said ram, and means responsive to said last named means for controlling said advancing and retracting means.

12. In a machine of the character described the combination of a hydraulically actuated member, hydraulic means for reciprocating said member, means for controlling said hydraulic means to. stop or start ram reciprocation, additional hydraulic means for advancing and retracting said member along the line'of reciprocation thereof, and means controlled by said member for automatically controlling the extent of advance and retraction of said member.

13. In a hydraulic press thecomblnation of *a hydraulically actuated ram, hydraulic means for reciprocating said ram, control means under the control of the operator for controlling ram reciprocation, additional hydraulic means for advancing and retracting said ram, means controlled by said ram for limiting the retraction thereof, and means under the control of said first named control means for'controlling said advancing and retracting, means.

14. In a hydraulic press the, combination of a hydraulically actuated ram, hydraulic means for reciprocating said ram within a limited range,

' additional hydraulic means coacting with said first named means for advancing and retracting said ram through an extended range, means under the control of the operator for starting and stopping reciprocation of said ram, and hydraulically actuated means for controlling theof said ram when reciprocation thereofceases.

.16. In a hydraulic press the combination of a hydraulically actuated ram, hydraulic means for reciprocating said ram within a limited range and for advancing and retracting the same through an extended range, automatic means normally controlled by said ram for normally controlling the advance and retraction'of said ram, and additional means under the control of the operator for controlling the advance and retraction of said ram.

17. In a hydraulic press the combination of a ram, means including an oscillatable hydraulic f circuit for reciprocating said ram, a second oscilnamed circuit, a reciprocating impeller for cscillating said second circuit, and valve mechanism for making and breaking communication between said'circuits to render said ram active or inactive.

18. In a hydraulic press the combination of a hydraulically actuated ram, a reciprocating impeller, hydraulic means energized by said imlatable'hydraulic circuit for energizing said first peller for reciprocating said ram, said means invalve operable to start and stop said ram, an

auxiliary impeller reciprocable in timed relation with said first named impeller for operating said valve, and means adjustable to vary the timed relation between said impellers to thereby regulate the time of operation of said valve.

20. In a hydraulic press the combination of a hydraulically actuated ram, a reciprocable im peller, hydraulic means energized by said im-. peller for driving said ram,'an auxiliary impeller reciprocable in timed relation with said first named impeller, meansactuated by said auxiliary impeller for starting and stopping said ram, and means for varying the timed relation between said impellers to thereby regulate the time of operation of said starting and stopping'means.

211 In a hydraulic press the combination of a reciprocating liquid impeller, a ram reciprocated synchronously with and by said impeller, a three position valve for controlling said ram, and fluid actuated means for shifting said valve selectively into one position to bypass liquid deliveredby said impeller and into either of two other positions to direct said liquid in a direction to cause said ram to be advanced irrespective of the direc-' tion of movement of said impeller.

22. In a hydraulic system the combination of a hydraulicpressure source, a member driven by liquid supplied from said source, a multi-position valve for controlling the operation oi said member, fluid channels connecting said valve to said source, fluid actuated .means for shifting said valve longitudinally into one position to bypass said liquid, a plurality. of fluid actuated means for shifting said valve longitudinally i to either a second or a third position'to cause saidmemher to be driven in a given direction irrespective of the direction of flow of liquid in said chan-' nels, and means for controlling said several fluid actuated means.

23. In a hydraulic system'the combination of a hydraulic pressuresource; a member driven by liquid supplied from said source, a multi-position valve for controlling the operation of said mem ber, fluid channels connecting said valve to said source, a pair of opposed fluid actuated means operable on said valve to shift the same into an intermediate position to bypassliquid 'from one chanriel to the other, and-additional fluid actuated -ram, a main impeller for delivering liquid to said v hydraulic means to operate the same and thereby reciprocate said ram in synchronism with said impeller, hydraulically actuated valve means for controlling said hydraulic means, an auxiliary impeller for supplying liquid to said valve means to operate the same, means ifor reciprocating said impellers, and means for bypassing the output of said auxiliary impeller during a part of the impeller stroke to thereby eiifect operation oi! said valve means at a given point in the stroke of said auxiliary impeller. v WALTER FERRIS.

GLEN MACOMBER.

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