US2278713A - Hydraulic cutting machine - Google Patents

Description

April 7, 1942.-

W. J. RIDDLE HYDRAULIC CUTTING MACHINE 2 Sheets-Shet 1 Filed March 28, 194,1

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l l M V April7,1942.' w1 mDDLE d .2,278,713-

HYDRAULIC CUTTING MACHINE .y

Filed Maron 28, 1941y 2 sheets-sheet 2 ATTOWEVS Patented Apr. 7, 1942 to The Hydraulic Development Corporation, Inc., Wilmington, Del., a'corporation of Delaf Ware Application March 28, 1941, serial 15 claims.

This invention relates to hydraulic machinery and, in particular, to hydraulically operable cutting machines.

It is an object of the. invention toy provide a cutting machine with a hydraulically operable y cutter and a hydraulic work piece holder, in which the work piece .holder is operable hydraulically without actuation of the cutter.

Another'object of the invention consists in the provision of a hydraulic cutting machine, in which the operation of the cutter automatically initiated in response to a predetermined pressure with which the work piece to be cut is pressed upon a support therefor. Y

It is another object of the invention to provide a cutting machine, in which the last portion of the cutting stroke is slowed down.

No. scam It is another object to provide a cutting mal chine, in which the cutter' is hydraulically operated by a fluid motor having adi a' :icing means and retracting means, and in which fluid expelled from said retracting means during the operation of said advancing means is usedl for assisting, the latter. n

Still another object consists in the provision of a cutting machine comprising a iluid motor with advancing and retracting-means, in which A the release of uid from the retracting means of said uid motor is responsive to the admittance of pressure iiuid to the advancing mean o f y said motor.

It is a still further object of the invention to provide a cutting machine vwith a fluid lmotor having advancing and retracting means, in which a pilot unloader valve is providedfor allowing release of fluid from said retracting means only when a predetermined pressure has builtl up in said advancing means.l

These and other objects and advantages of the invention will appear more clearly from the folmounted therein a piston 2 with apiston rod 3. The'said cylinder pistons and piston rods are substantially equal. Connected to the piston rods 3-'in any convenient manner is the cutter bar 4 for cutting the work piece.

The main' cylinders I arestationary and supported by the press head 5` which is spaced from and connected in any convenient manner with the press bed 6 for .supporting the1 work piece.

-A work piece placed on 'the press bed 6 is clamped or held thereagainst by means of hold-down .cylinders 1, the effective number of which may be varied according to .the size of the'work piece, which may b e sheet metal, paper, or the like.

Reciprocably .mounted in eachv hold-down cylindex' 1 is a piston 8 with a piston' rod 9 adapted to engage the work piece. Between the lower surface of the piston 8 and the bottom of the cylinder 1 is arranged a lspring I0 for lifting or returning,- the piston 8 to its initial position when the hold-down or clamping operation has been l completed. l Y I The upper. portion of each of the hold-down cylinders 1 communicates with a conduit I l leading into a'common conduit I2 which in its turn is connected to a conduit I3, comprising an adjustable'choke I4. The opening in the choke valve Il determines the rate at. which pressure iluid enters the hold-down cylinders -1. The `conduit I3 leads to an adjustable admission valve I5 of the type shown in Figure 2, which valve will be described in detail later.

Communicating with the admission valve I5 is a conduit I6 leading into aconduit I1, which communicates with the upper portion of the two main cylinders I. The lower portion of the main cylinders l isadapted to communicate with each other through a conduit I8. The ports I9 at which the conduit I8 communicates -with the lowing specication in connection with the accompanying drawings, in whichz Figure .1 is a front view of a hydraulically operable cutting machine according to the invention.

Figures 2 and 3 illustrate valves used in the hydraulic circuit of the -present invention.

Figure 4 illustrates diagrammatically the hydraulic circuit of a cutting machine according to the invention.

Structural arrangement Referring to the drawings in detail, the cutting machine shown therein comprises a pair of main cylinders I, each of which has reciprocably main cylinders I are adapted'to be by-passed' by conduits 20 pertaining toeach of the main cylinders l comprising a choke valve 2l, and communicating with al conduit 22 respectively leading into the cylinders I adjacent the bottom portionthereof. Each of the conduits 22 com- .prises a. check valve 23, which opens in the direction of the respective arrow.

The admission valve I5 may be by-passed by a conduit 24 comprising a-check valve 25 and communicating with its conduits I6 and I3a respectively, which latter is connected4 to the admission valve I5. vConnected to the conduit I8 is a conduit 26 leading to a pilot unloader valve A 21 of the type shown in Figure 3, which will likewise be described later. A pilot line 28 in- 21 through a leakage line 31.

Aterconnects the pilot unloader valve 21 and the conduit Ita. A further conduit 29 comprising a check valve 38 also leads from lthe pilot un loader valve 21 to the conduit I3a, which is connected to a four-way valve 3 I Also connected to the four-way valve 3|- is a conduit 32 comprising a shutoi valve 33 and a check valve l34 and leading to the1c'onduit'28.

prising a needle valve 39 and leading to the conduit 26. Another line, 40, comprising a check valve 4| is adapted to effect communicationV between the tank 31 and the conduit. I1. The tank 38 is also connected with a conduit l42 leading movedbeyond the same by a predetermined distance.

Referring now tothe valve of Figure 2, the same comprises substantially a casing 19 which is joined to a valve housing 88, for instance, by a threaded connection. Reciprocably mounted partly within the casing 19 and the valve housing 88 is a plunger 8| which is vfree to move up 4and down against the pressure of a compression spring 82, which makes contact against the head 83 on the plunger 8|.v The compression spring 82 `may be adjusted to any desired pressure by to the suction side of a pump 43, the pressure side of which is connected to the conduit 44 comprising a pressure relief valve 45, which inits structure may correspond to the valve shown in Figure 2.

The relief valve 45 is adapted'to communicate on one hand through conduit 46 with the'tank 36 and on the other hand through conduit 415 with the four-way valve 3l. The iour-way'valve 8| is so arranged that when its valve member (not shown) is moved into its left-hand end .position with regard to Figure 4, the conduit 41 communicates with `the conduit I3a, whereas when the valve member of the four-way valve 8| is shifted to its right-hand end position, the conduit 41 communicates with the conduit 32. When the valve member of the four-way valve 3| is in its intermediate position, the conduit 41 communicateswith the conduit 35. The fourway valve 3| does not form a part of the present invention and for a more detailed description thereof, reference may be had to Patent No. 2,109,162 to Boehle.4 The valve member of the valve 3| is connected with a shift arm 48 pivotimmature sl which carnes a third switch made 82 adapted to electrically connect the line 83 comprising a normally vclosed limit switch 84 and leading to the main supply line 85 with the line 86 connected to one end of the solenoid 61. The solenoid 81 is ,furthermore 'connected with a line 88 adapted by closureof the push button 69 to be electrically connected with the line 10.1eading to the main supply line 65. 'I'he other end of the solenoid 61 is connected, by means of line 1I, with the main supply line 12which is also connected with the line `58. 1

Thearm 13 of the three-arm lever 50 is continuously urged in anti-clockwise direction by..

means of a spring 14 attached to the arm 13,

which arm is also pivotally connected to a push rod `1li. 'I'he push rod 15 has adjustably mounted thereon a collar 18 adapted to be engaged by an arm 11 carried by the cutter bar 4. Also carried by the cutter bar 4 is an adjustable abutment screw 18, which is preferably so adjusted that it opens the limit switch 84 after the cutter bar 4 has completely cut thev work piece and rotating the adjusting screw 84, which pushes Vthe spring cap 85 downwardly against the compression spring 82. 'The adjustment is maintained in locked position by the lock nut 86.

Contained within the' upper part of the valve housing 88 is a plunger lifting chamber 81 through which the plunger 8| passes. Within this chamber, the plunger diameter is enlarged to form the differential lifting area 88 which is of annular form. One side of the plunger lifting chamber 81 has the inlet port 89 passing through the walls of the valve housing 80 where it con tinues in the pilot line 28 (Figure 4).

- The chamber 90. below the lower end of the plunger 8| .is connectedwith the conduit 29.

The valve chamber 9| of the valve housing 80 is connected with the conduit 26, while the casing 19 is connected with the leakagev conduit 31 leading to the tank. The device of Figure 2 operates in suchv a manner that when the pressure in the plunger lifting chamber 81 reaches a predetermined value, the plunger 8| is lifted by lthe uid acting on thelifting area 88 so that i'luid from conduit 28 may pass through the valve chamber 9| into the conduit 29.

Referring to Figure 3, the valve shownA therein is somewhat similar to the valve of Figure 2, and similar parts are, therefore, designated with the samerreference numerals, however, with the additional letter a. In contrast to the valve of Figure 2, the valve chamber 9Ia communicates on one hand with the conduit I3 and on the other hand with the conduitv I3a so that a continuous'connection is established between the conduits I 3 and I3a, irrespective of the position of the plunger 8Ia. The chamber 98a below the lower end of the plunger 8Ia communicates with the conduit I6. When a predetermined pressure is built up in the valve chamber 9Ia, this pressure acts on the lifting area 88a, thereby lifting the plunger v8Ia and'establishing communication between the conduit I6 and the conduits I3 and I3a.

Operation Assuming that all parts of the device shown in the drawings occupy the position of Figure 4, and that it is now desired to start a working cycle, the operator pushes the push button 69, thereby closing a circuit comprising the main supply line 85, lines 10 and 68, solenoid 61, line 1I and main supply line 12. Asa result thereof solenoid 61 is energized and causes the armature 6| to move upwardly so that the switch blade 62 establishes a lholding circuit for the solenoid 61, while the switch blades 59 and 60 close the energizing circuit for the solenoid 54. As a result of the enerestablishes connection between the conduit `41V and the conduit I3a, while simultaneously establishing connection between the conduits 35 and 32.

Assuming that previously the pump 43 was' solenoid 54. 'rhesprmg 14 then shifts the threestarted, pressure fluid is now delivered by the pump 43 through the conduit 41, the four-way valve 3l, the conduit I3a, valve chamber 9Ia of the valve I5, vthe conduits I3 and I2 and into the hold-down cylinders 1 where the pressure fiuid acts upon the respective pistons 8 and moves the latter downwardly against the thrust of the springs I0 so that the piston rods 9 grip the work piece to be cut.

When a predetermined pressure has built up in the cylinders 1 so' that the work piece is' pressed with a predetermined pressure against its support or press bed 6, this pressure overcomes the thrust of the spring 82a so that the plunger 8Ia is lifted, thereby establishing connection between theconduit I 6 and the conduits I3 and I3a. As a result thereof, pressure fluid from the con- Y duit I3a now passes through conduit I6 into the conduit I1 from where it flows into the main cylinders I above the pistons 2. This pressure acting upon the pistons 2 causesV the latter to compress the fluid in the. main cylinders I below the pistons 2 which, up to this time, could not escape since the check valve 34 allows passage of fluid only in the direction indicated by the arrow pertaining thereto, while the needle valve 39 is closed and the plunger 8'I of the valve 21is in its lower position, in which it prevents communicaticn betweenthe conduits 26 and 29. However, since the pressure, now acting upon the pistons-2 and c-onveyed thereto through the conduit I1, also prevails in the pilot line 28, this pressure is conveyed into the-lifting chamber 81 valve 3D into the conduit 29, and is then conveyed.

through the conduit I3a, the valve I5 and the conduits I6 and I1 into the upper portion of the main cylinders I. In other words, the pressure uid expelled by the pistons 2 aids the downward movement of the said pistons.

As will be seen from the drawings, before the pistons 2 have completed their downward stroke, i. e., preferably before they have completely cut through the work piece, the pistons 2 close the ports I9 so that the fluid beneath the pistons 2 can escape from the main cylinders I only through the conduits 22, the choke valves 2I and the conduits into the conduit I8. Depending on the adjustment of the choke valves 2|, the last portion of the downward movement or cutting stroke of the pistons 2 may' be slowed down to any desired degree. This slow-down movement prevents any damage to the work piece, whichv otherwise might be caused if the cutter bar 4 cuts through the work piece atahigh speed and then suddenly meets no further resistance.

When the cutter bar 4 has completely cut arm lever in anti-clockwise direction and by means of the shiftarm 4'8 shifts the valve member of the four-way valve-3l into its left-hand endposition, thereby establishing hydraulic connection between the conduits 41 and 32, while simultaneously effecting communication between the conduits I3a and 35. Pressure fluid is now delivered by the pump 43 through conduit 41, four-way valve 3|, conduit 32, the open shutoff valve 33, check valve 34, conduits 26, I8 and 20, check valves 23 and conduits 22 into the lower portion of the main cylinder I. Consequently, the pistons 2 start their upward or retraction movement, while expelling the fluid in the upper portion of the main cylinders I into the conduit I1, from where it ows through conduits I6 and 24, check valve 25, conduit I3a and the conduit 35 into the tank-36. y

Since, due to the hydraulic communication now established between the conduits I3a and 35a pressure drop occurs in the conduits I3 and I2, the springs I0 beneath the hold-down pistons 8 immediately return thecutter bar 4 to its lifted position, thereby enabling the operator to remove the cut off portion of the work piece and to place thework piece into a ynew -position for a further cut, While the cutter bar 4 is still moving to its retracted position.

Due to the pressure drop inthe conduit I3a, the pressure in the pilot line 28 likewise drops so that the compressing spring 82 of the valve 21 again causes the plunger 8l t0 closethe hydraulic communication between the conduits 26 and 29. l v

When the pistons 2 and the cutter bar '4 connected thereto havereached a predetermined position during the said retraction stroke, the arm 11 engages the collar 16, thereby lifting the push rod 15 so that the latter, through the intervention of the three-arm lever 50 and the shift arm 48, moves the valve member of the four way valve 3I to its intermediate position, in which the conduit 35 is connected with the conduit 41. When this connectionl has been established, the pressure uid delivered by the pump 43 is merely circulated through the conduit 41, the four-way valve 3I, conduit 35 and tank 36, from where it ows through the conduit 42 tothe suction side of the pump 43. As a result the pistons 2 and, therefore, the cutter bar 4 come to a halt.

Since, as previously mentioned, the pilot unloader valve 21 had closed the hydraulic connection between the conduits 26 and 29, the pressure in the lower portion of the main cylinders I is `maintained and the pistons 2 are held in their llfted posit1on. A new cycle may then be started by again actuating the push button 69.

In order to assist in setting up the cutter bar 4,

provision is made to inch the' cutter bar slowly.

is running. The needle valve 39 may then be opened to allow the weight of the pistons 2 to expel any desired restricted quantity of iiuid from the lower portion of the main cylinders I into the mature 6I with itsblades 62, 59 and 68 drops back to its open position, thereby deenergizing the conduits I8, 26 and 38, from where the fluid may pass into the tank 36. In this way any gradual downward movement of the pistons 2 and the cutter bar 4 connected thereto may be effected.

Fluid is supplied to the upper portions of the ranlam cylinders I through the small check valve vIf, for some reason, any .undue pressure' fshoulddevelop' in the' conduit 44 or the conduit 41,1thispressure will be released into the tank 3i =throughthe valve 45` which, as previously men- 'f tioned, corresponds in yits construction to that of the Valve l5. Y

It will be understoodthat I desire to comprehend within my invention such modifications as come within the scope of the claims and the invention.

Having now fully described my invention, what I claim as new and desire to secure by Letters I Patent is:

means hydraulically `'connected with said pressure responsive means for allowing iiow of iluid from said retracting means to said advancing means, while preventing the flow of iluid in the reverse direction.

5. In a hydraulic system for a cutting machine, a main plunger having associatedtherewith uid operable advancing and retracting means for vreciprocating said plunger, a fluid operable auxiliary plunger, conduit means for hydraulically interconnecting said advancing means and said auxiliary plunger, meansarranged in said con- 1. In a hydraulically operable cutting machine,

a main plunger having associated therewith fluid operable advancing and retracting means for reciprocating said plunger, cutting means operduit means and responsive to a predetermined pressure on said auxiliary plunger for eiiecting hydraulic connection betweensaid advancing means and saidl auxiliary plunger, and valve means hydraulically connected with said retracting means for preventing escape of iluid from said retracting means prior to the establishment of said predetermined pressure to prevent acciy dental advancing movement of said main plunger.

movable independently of said main plunger for holding a work piece to be cut, said holding plunger being adapted hydraulically to be connected with said advancing means, and pressure responsive means `responsive to a predetermined pressure on said holding plunger for establishing hydraulic connection between said holding plunger and said advancing means.

3. In a hydraulically operable cutting machine, a cylinder, a double-acting plunger reciprocably mounted in said cylinder, cutting means operatively connected with said plunger, a iiuid source adapted to supply pressure uid to saidcylinder for actuating said plunger, work piece holding means for vholding a work piece during the cutting operation, iiuid operable advancing means associated with said work piece holding means for advancing the same, conduit means for conveying pressure fluid from said iiuid source to said fluid operable advancing means independently of the supply of pressure fluid to said cylinder, yielding means associated with said holding 6. In a hydraulically operable cutting machine, a main cylinder, a double-acting main plunger reciprocable in said main cylinder, a cutter bar operatively connected with saidl main plunger, an auxiliary uid operable plunger for holding a work piece during-the cutting operation, a fluid source adapted to supply 'pressure fluid to said main plunger and saidauxiliary plunger, conduit means for hydraulically interconnecting said iiuid source with said plunger, valve means in said conduit means for sequentially admitting pressure uid from said iluid source first to said auxiliary plunger and thereafter to said main plunger, and fluid pressure vresponsive means hydraulically connected with the'retraction side of said main plunger and responsive to a predetermined pressure on the advancing side oi' said means and constantly urging said holding means into retraction position, and iiuid pressure responsive means responsive to a predeterminedl pressure on said work piece holding means for establishing hydraulic connection between said fluid source and one side of said cylinder and for conveying iiuid expelled from the other side of said cylinder to said iirst mentioned side of `said cylinder to assist the advancing movement of said plunger.

4. In a hydraulically operable cutting machine, a main plunger having associated therewith fluid operable advancing and retracting means for selectively advancing orretracting said plunger,

cutting means operatively `connected with said4 main plunger, a fluid operable holding'plunger movable independently of said main plunger for holding the work piece to Vbe cut, said holding plunger being adapted hydraulically to be connected with said advancing means, pressure responsive means responsive to a predetermined pressure on said holding plunger for establishinghydraulic connection between Isaid holding plunger and said advancing means and between the latter and said retracting means, and valve -main plunger for conveying pressure iiuid expelled from the retraction side oi said main plunger to the advancing side thereof.v

7. In a hydraulically operableA cutting machine, a main cylinder, a double-actingmain plunger reciprocably mounted insaid main cylo inder, cutting means operatively connected with said main plunger, said main cylinder having two ports spaced in the longitudinal direction of said main cylinder, Achoke means associated with one of saidv ports for restricting the escape oi iluid from said main cylinder when said main plunger approaches the end of its cutting stroke, an auxiliary uid operable plunger for holding a work piece during the cutting operation, and valve means hydraulically connected with said auxiliary plunger and adapted to prevent the supply oi' pressure iluid to the advancingside of said main plunger prior to the-,establishment of a predetermined pressure on said auxiliary plunger.

8. In a hydraulically operable cutting machine, a main cylinder, a double-acting main plunger reciprocably mounted in said main cylinder, cutting means operatively connected with said'main plunger, said main cylinder having two ports spaced in the longitudinal direction of said main cylinder, choke means associated with one of said ports for restricting the escape of iluid from said main cylinder when said main plunger approaches the end of its cutting stroke, bypass y or to said auxiliary plunger, control valve means hydraulically connected with said uid source for preventing hydraulic communication between the latter and the advancing side of said ymain plunger prior to the establishment of a predetermined pressure on said auxiliary plunger, and by-pass valve means for hydraulically by-passing said control valve means during the retraction stroke of said main plunger to effect hydraulic communication between said advancing means and said fluid source.

.10. In a hydraulically operable cutting machine, a main plunger, fluid operable advancing and retracting means associated with said plunger for actuating the same, cutting means operatively connected with said main plunger,` a uid operable auxiliary plunger for holding a work piece to be cut, a fluid reservoir, a pressure iiuid pump having its suction side connected with said reservoir and adapted selectively to supply pressure fluid to said auxiliary plunger and said advancing means or to said retracting means, iirst conduit means connecting said fluid reservoir with said advancing means, a check valve agranged in said first conduit means and adapted to admit fluid from said reservoir to said advancchine, a main plunger having associated therewith uid operable advancing and retracting means for actuating said plunger, a constant delivery pump adapted selectively to supply pressure fluid to said advancing and retracting means, a four-way valve adapted selectively to connect said pump with said advancing means or said retracting means or to by-passthe delivery of said pump to an exhaust, cutting meansA operatively connected with said main plunger, an

auxiliary plunger adapted hydraulically to be connected with said pump to lexert holding pressure on awork piece to be cutyfluid pressure responsive means hydraulically connected with said auxiliary plunger and adapted in response to a predetermined pressure on thelatter to efiect hydraulic communication between the advancing side of said main plunger and said pump, and valve means operable in response to a predetermined point of travel of said main plunger after completion of the cutting operation for reversing hydraulic communication between said.pump and said advancing and lsaid retracting means.

13. In a hydraulically operable cutting ma chine, a plurality of double-acting main plungers,

cutting means-'operatively connected with said main plungers, conduit means connecting the advancing sides 0f said main plungers and being adapted hydraulically to be connected with the pressure side of a pressure pump, a plurality of auxiliary plungers adapted to be supplied with ing means, but not vice versa, controlling means for sequentially admitting pressure iiuid to said auxiliary plunger and said advancing means, second conduit meansadapted to supply pressure uid 4from said pump to said retracting means, a shutoff valve in said second conduit means for interrupting hydraulic communication between the pressure side of said pump and said retracting means, third conduit means adapted to establish hydraulic communication between said retracting means and said reservoir, and adjustable choke means for varying the rate of ow of uid from said retracting means to said reservoir.

11. In va. hydraulically operable cutting machine, a main plunger having associated therewith fluid operable advancing and retracting means for reciprocating said plunger, cutting means operatively connected with said plunger, a fluid operable auxiliary plunger for holding a work piece during the cutting operation, a pressure :duid source for supplying pressure fluid selectivelyA to said auxiliary plunger and said advancing means or to said retracting means, fluid pressure responsive means hydraulically connected with,said iiuid source for admitting pressure iiuid 'to said advancing means in response to a predetermined uid pressure on said auxiliary plunger, and yielding meansresponsive to the release of fluid pressure on said auxplunger for spacingy the same from the work piece.

12. In a hydraulically operable cutting mahydraulically connected pressure liiuid from said pump to hold a work piece during the cutting operation, yielding means continuously tending'to space said aux-` iliary plungers from said work piece, further conduit means interconnecting the retraction sides of said main plungers, rst control valve means with said auxiliary plungers for preventing supply of pressure fluid to the advancing sides of said main plungers prior to the establishment of a predetermined pressure on said auxiliary plungers, second control valve means for preventing the escape of fluid from the retraction Vsides of said main plungers priorto the establishment of a predetermined pressure on the advancing sides of said main plunger, and by-pass valve means for bypassing said nrst and second control valve means during the retraction stroke of said main plungers.

14. In a hydraulic system, the combination of A a hydraulic hold-down means, a hydraulically operable shear, and means to bring about the actuation of the shear upon the accomplishment of a predetermined pressure on said hydraulic holddown means.

l5. In a hydraulically operable shear, a main plunger having associated therewith fluid operable advancing and retracting means for reciprocating said main plunger, a uid operable auxiliary plunger, conduit means hydraulically interconnecting said advancing means and said auxiliary plunger',4 and means arranged in said conduit means and responsive to a predetermined pressure on said auxiliary plunger for effecting hydraulic communication between said advancing means and said auxiliary plunger.

WILLIAM J. RIDDLE.

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