US3273434A - Shearing machine and method - Google Patents

Shearing machine and method Download PDF

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Publication number
US3273434A
US3273434A US413539A US41353964A US3273434A US 3273434 A US3273434 A US 3273434A US 413539 A US413539 A US 413539A US 41353964 A US41353964 A US 41353964A US 3273434 A US3273434 A US 3273434A
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United States
Prior art keywords
ram
shearing
movable
shearing element
shear
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US413539A
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English (en)
Inventor
Albert F Hausman
Felix A Chiplis
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Amsted Industries Inc
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Amsted Industries Inc
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Priority to US413539A priority Critical patent/US3273434A/en
Priority to DE1965A0048418 priority patent/DE1502680A1/de
Priority to FR6728A priority patent/FR1429541A/fr
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Publication of US3273434A publication Critical patent/US3273434A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D28/00—Shaping by press-cutting; Perforating
    • B21D28/02—Punching blanks or articles with or without obtaining scrap; Notching
    • B21D28/16—Shoulder or burr prevention, e.g. fine-blanking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D28/00—Shaping by press-cutting; Perforating
    • B21D28/002—Drive of the tools
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T225/00—Severing by tearing or breaking
    • Y10T225/30—Breaking or tearing apparatus
    • Y10T225/371—Movable breaking tool
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/04—Processes
    • Y10T83/06—Blanking
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/444—Tool engages work during dwell of intermittent workfeed
    • Y10T83/4501—Work feed means controlled by means mounted on tool or tool support
    • Y10T83/4503—Such means drives the work feed means
    • Y10T83/4511—On return stroke of tool
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/869—Means to drive or to guide tool
    • Y10T83/8788—Tool return mechanism separate from tool advance mechanism
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/869—Means to drive or to guide tool
    • Y10T83/8821—With simple rectilinear reciprocating motion only
    • Y10T83/8827—Means to vary force on, or speed of, tool during stroke
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/869—Means to drive or to guide tool
    • Y10T83/8821—With simple rectilinear reciprocating motion only
    • Y10T83/8841—Tool driver movable relative to tool support

Definitions

  • This invention relates to the die shearing of material such as metal, in which the material is stressed in shear to the point of fracture, that is, beyond its ultimate strength, between two cutting edges of die components, which are forced toward each other in passing relation, that is, in the direction of, and on opposite sides of, the plane of shear stress.
  • the invention relates especially to shearing operations in which the character and trueness of the cut face or faces are critically significant.
  • Operations which use die shearing include, for example, the punching of strip or sheet stock in punch presses to provide holes through the stock, the cutting of blanks from stock in blanking presses, the cutting of pieces from continuous rod or wire, etc.
  • the most common form of press used for performing operations of the kind mentioned is of the crank type in which a reciprocable member carrying one of the die components, such as the punch of a punch and die set, is connected through a connecting rod to a crank or eccen tric on a drive shaft.
  • the motion of the movable die or punch is essentially a harmonic motion in which the velocity of the die or punch is relatively low and decreasing as it approaches the work and moves through its cutting operation.
  • the linear velocity of the movable die as it engages the work and performs its cutting operation will depend upon the speed of the drive shaft; and where the work is automatically fed by mechanism driven from the same drive shaft, the linear speed of the movable die will depend upon the feeding frequency.
  • the lineal speeds of the moving punch or other shear die as it approaches and progresses through its shearing operation may be of the order of 1 foot per second and the practical upper limit does not exceed about 2 feet per second.
  • Another conventional shearing machine commonly used for cut-off operations, employs a cam to drive the cut-off die.
  • the die velocity accelerates from substantially zero at the start of the cutting movement to a maximum near the end of the die cutting movement.
  • the practical limit on die velocity is of the order of 2 feet per second as a maximum.
  • shearing dies used in conventional machines require certain critical clearances, depending on the type of material being cut, its thickness, and its hardness; and with those critical operating clearances, the dies produce certain characteristics results at the cut edges.
  • the stock undergoes plastic deformation which produces a rounded edge, or edge radius, bordering the contact area of each die on the face of the material.
  • the die edges penetrate and cut the material, which produces a substantially straight out band on the cut face. The penetration reduces the cross-section of stock remaining between the dies, and as penetration increases, fracture occurs through the remaining stock cross-section, and this produces a cleavage surface which is usually irregular and rough and which lies at an angle to the direction of die movement.
  • edge radius, the cut band, and the angled cleavage surface appear on both edge faces produced by the shearing.
  • the plastic See deformation produces .a substantial edge radius at the punch-entrance end of the hole, the penetration produces a narrow substantially cylindrical cut band, and the fracture produces a frusto-conical cleavage surface which flares outward from the cut band to the opposite face of the stock.
  • it is necessary with conventional operations first to punch a hole having these non-cylindrical wall portions, and then to shave the hole to the desired cylindrical configuration and size in a separate secondary operation. Similar secondary operations are necessary on other conventionally sheared parts if it is desired to produce true faces at right angles to the work-piece surface.
  • the high die shearing speeds promote smoothness and increase trueness of the edge faces of the blanks.
  • cut-off operations such as in shearing pieces from rod or other continuous lengths of stock, the high speed shearing operations will produce substantially undistorted square and flat ends where prior shearing produced distorted ends and rough and angular end faces.
  • the mass and velocity of the ram must of course provide sufficient energy to shear and fracture the material being Worked on, and excess energy should be held within reasonable limits since it must be absorbed by the machine without performing useful work.
  • the minimum lineal tool velocities which are practical in accordance with the invention are velocities of at least 6 to 8 feet per second, with the lower velocities generally applicable to punching operations and with higher minimum velocities desirable for cut-off operations. Desirably, velocities higher than the minimums are used, and We preferably use velocities of at least to 12 feet per second. The velocities used may be substantially higher than these minimums, with improved results, and we have used velocities of the order of 50 feet per second in cut-off operations. While the shearing operation itself appears to impose no top limit on the velocity used, practical considerations require that the velocity not exceed the limitations of the mechanical design and strength of the die components and the machine structure.
  • the ram is accelerated by subjecting it to force derived from a confined body of air or other gas maintained under elevated pressure.
  • the ram is retracted with accompanying compression of the gas by power-operated means and, after retraction, is abruptly released to permit it to accelerate and acquire sufficient momentum to force the cutting tool through the work at high velocity.
  • the change in volume of the confined gas which accompanies retraction and advance of the ram is small relative to the total volume of the gas, in order that the ramaccelerating force exerted by the gas will not decrease unduly as the ram advances.
  • a portion of the confined gas is contained in a cylinder within which a piston is disposed.
  • Either the piston or the cylinder is stationary, while the other of those elements is operatively connected to the ram.
  • the ram and cylinder may conveniently be integral with each other.
  • Means for retracting and releasingthe ram may take various forms such, for example, as a rotating, spiral cam having a ram retracting lobe which terminates abruptly.
  • Another suitable form of such a means comprises a crank-reciprocated ram-retractor and a latch which retains the ram in retracted position while the retractor advances toward the work and is then abruptly released.
  • the working stroke of the ram is limited by a stop positioned to be engaged by the ram after it has struck the cutting tool and forced it through the cutting stroke, and to pervent substantial over-travel.
  • Retraction of the cutting tool after performance of its cutting stroke may in some instances be effected by a spring; while in other instances it may be desirable to effect its retraction by power-operated means operating in timed relation with the ram-retracting means.
  • the work-piece is held against the stationary die component during the shearing operation, as by a stripper plate or other hold-down device, under high pressure.
  • FIG. 1 is a side elevation of a punch press embodying the invention and adapted to punch holes in successively fed, discrete blanks;
  • FIG. 2 is a rear elevation of the punch press of FIG 1;
  • FIG. 3 is a vertical section through the bottom portion of the press on the line 33 of FIG. 1;
  • FIG. 4 is a horizontal section on the line 4-4 of FIG 3;
  • FIG. 5 is a detail view in partial section on the line 5-5 of FIG. 1;
  • FIG. 6 is a fragmental vertical section on the line 6-6 of FIG. 2;
  • FIG. 7 is a fragmental plan view of another machine which embodies the invention and is adapted to cut pieces of predetermined length from a continuous rod or wire;
  • FIG. 8 is a vertical, axial section through the shearing mechanism of the machine illustrated in FIG. 7, taken on the line 8-8 of FIG. 7, showing the ram and cutting tool in their retracted positions;
  • FIG. 9 is a vertical section onthe line 99 of FIG. 8;
  • FIG. 10 is a horizontal section on the line 10-10 of FIG. 8;
  • FIG. 11 is a view similar to FIG. 8 showing the positions of the ram and cutting tool at the termination of their working strokes.
  • the punch press illustrated in FIGS. 16 embodies a frame comprising vertical, parallel side plates 10 and 11 secured at their lower ends to a base 12 and at their upper ends to a top plate 13. Between the side plates, a hammer or ram 15 is mounted for vertical reciprocation. Conveniently, the ram 15 is a rectangular parallelapiped of metal the center portion of which is cut out to provide a vertically elongated opening extending through the ram from front to back. Guide rollers 16 supported in any convenient manner from the frame engage the sides, the front, and the back of the ram to guide it in its vertical reciprocation.
  • a piston rod 17 Connected to the top of the ram 15 is a piston rod 17 which extends upwardly through the top plate 13 and projects into the open lower end of a cylinder 18, where it is provided with a piston 19.
  • the upper end of the cylinder 18 is enlarged to provide an accumulator 2% adapted to contain a considerable volume of air or other gas under pressure.
  • the supply of air or other gas under pressure in the cylinder and accumulator is maintained through a pipe 21 containing a suitable pressure-regulating valve 22.
  • a main shaft 25 which is rotatably supported in suitable bearings 26 from the side plates 10 and 11 and which extends through vertical slots in the sides of the ram 15, such slots being long enough to permit the desired vertical movement of the ram.
  • the cam 27 is shaped so that as the shaft 25 rotates, in a counterclockwise direction as shown in FIG.
  • the cam will gradually raise the ram 15 and piston 19 against the pressure in the cylinder and accumulator and then abruptly move out of engagement with the roller 28 to permit the ram to descend rapidly under the fluid pressure exerted on the piston 19.
  • descent of the ram is limited by ram-stops 29 supported on the base 12 in position to be engaged by the descending ram before the roller 28 can impinge on the low point of the cam 27.
  • the shaft 25 projects outwardly beyond the bearing 26 on the side plate It] and is provided with a pulley 30 driven through a belt 31 from any convenient source of power.
  • the arrangement of punch and die mechanism embodied in the machine will of course depend upon the nature of the work the press is to perform.
  • the punch press shown in FIGS. 1-6 is designed for perforating small, automatically fed blanks, specifically, for providing the pitch holes in the link plates P of a powertransmission chain.
  • the base 12 is recessed for the reception of a die pad 32 containing die bushings 33.
  • a hold-down and stripper plate 34 carried by guide rods is normally urged downward to hold the link plates P against the face of the die pad 32 and bushings 33, by springs 152 acting on a crosshead 153 carried by the lower ends of the guide rods.
  • the pressure on the plates P is desirably about 1200 lbs. per square inch.
  • the plate 34 slidably receives and guides punches 35 respectively aligned with the holes in the die bushings.
  • the punches 35 are provided with enlarged heads 36 having at their lower ends still larger flanges 37. Upward movement of the punches in the stripper 34 is limited by a stop plate 38 supported from the ram stops 29 and provided with openings large enough to pass the heads 36 but too small to pass the head-flanges 37.
  • the bottom .of the ram 15 is provided with a punch-engaging member 40 which is vertically adjustable in the ram to vary the extent to which the punches 35 are forced downwardly when the ram descends.
  • the member 40 is a plug screwthreaded into the bottom of the ram.
  • the punches are loosely received (FIG. 6) below their flanges 37 in openings in the ends of lifting arms 42 secured to a rock-shaft 43 rotatably supported from the side plates and 11.
  • the shaft 43 projects outwardly beyond the side plate 11 where (FIG. 1) there is secured to it an arm 44 projecting upwardly and carrying at its upper end a follower 45 engaged by a cam 46 secured to the main shaft 25.
  • a spring 47 acting on the arm 44 may be employed to maintain the cam follower 45 in engagement with the cam 46.
  • the cam 46 is so shaped and so oriented on the shaft 25 that promptly after the cam 27 has moved out of engagement with the cam follower 28 and the ram has descended the cam 46 will rock the shaft 43 in a direction to cause the arms 42 of the cam 27.
  • the machine shown in FIGS. 1-6 embodies two independently operable latches, mounted respectively on the side plates 10 and 11.
  • the latch on the side plate 10 comprises (FIG. 3) a cup-like guide 50 mounted in a hole in the side plate '10 and adapted to receive a latch member 51 slidable in the guide between positions in which it lies respectively within and laterally beyond the path of the descending ram 15.
  • the latch 51 has a shank which projects outwardly beyond the guide 50 for operative connection to a lever 52 fulcrumed to the side plate 10 near the rear edge thereof.
  • the other latch mechanism that carried by the side plate 11, is associated with feeding mechanism to be described below.
  • Such other latch mechanism comprising a cup like guide 55 mounted in a hole in the side plate 11 and arranged to receive a slidable latch member 56 which, like the latch member 51, can be projected into the path of the ram 15.
  • the latch member 56 is provided inside the guide 55 with a notch receiving the intermediate portion of an operating lever 57, which extends through slots in the front and back of the guide 55, and is fulcrumed at its rear end to the side plate 11.
  • 1-6 is intended for use in piercing the link plates of power transmission chain.
  • a supply of such plates to be pierced is contained in tubular magazine 60 supported vertically at the front of the machine with its lower end received in a socket 61 which has an opening permitting the plates in the magazine, while still stacked in superposed relation, to pass downwardly through the socket until the lowermost plate rests on the upper surface of the base 12, as will be clear from FIG. 6.
  • the rear of the socket 61 is provided with a notch leading to a guide groove through which the plates to be pierced may be advanced from the socket 61 into piercing position over the dies 32.
  • feed mechanism embodying a feed slide 62 mounted for fore-and-aft reciprocation in the front portion of the base 12.
  • a feed tongue 63 which rests on the upper surface of the base 12 and which has a thickness slightly less than the link plates to be pierced.
  • each of the locating jaws 64 is provided at its inner end with a pair of spaced rollers 65 which receive between them the rounded end of the link plate.
  • the jaws 64 are spring-pressed inwardly by spring 66 toward positions determined by adjustable stop screws 67.
  • a feed cam 70 rigidly secured to the drive shaft 25.
  • the cam 70 serves to oscillate a pivotally mounted arm 71 connected through a link 72 to an arm 73 rigidly secured to a rock-shaft 74 that extends transversely of the machine below the feed slide 62.
  • Such slide is provided with a slot which receives the end of a second arm 75 rigidly secured to the shaft 74.
  • a spring 71' acts on the arm 71 to maintain a cam following roller 76 on the arm in contact with the cam 70.
  • the cam 78 is so shaped and so oriented with respect to the earns 27 and 46 that it retains the feed slide 62 in retracted position against the force of the spring 71' until after the ram 15 has begun its upward movement and the fingers 42 have raised the punches to clear the plate just pierced so that such plate will be free to move when the feed slide does advance.
  • the cam 70 places the feed slide in retracted position preferably before the cam reaches the top of its stroke and in any event before the cam, in descending, reaches a position where it would obstruct inward movement of the latch member 56.
  • the arm '71 is associated with the latch member 56 in such a way that when the latch member is advanced to retain the ram 15 in elevated position the feed mechanism will be rendered inoperative.
  • the guide 55 for the slide 56 is formed at its outer end with a boss 78 on which the arm 71 is pivoted for oscillatory movement.
  • the latch member 56 has a shank 79 which projects through such boss and rotatably supports at its outer end a cross piece 80 from which a pair of parallel pins 81 project inwardly parallel to and on opposite sides of the shank 79 for slidable reception in holes in the arm 71.
  • the pins 8-1 lie within the arm 71 in the position shown in FIG. 5 and do not project into the holes 86 of the stationary plate 82. Accordingly the arm 71 is free to oscillate on the boss 78, carrying with it the pins 81 and the cross-piece 80. If it is desired to interrupt both reciprocation of the ram 15 and operation of the feeding mechanism, the lever 57 is urged inwardly, or to the right of FIG. 4.
  • the operator will advance the latch member 51 instead of the latch member 56.
  • This operation is effected byapplying an inward effort to the operating lever to cause the latch member 51 to move beneath the ram 15 as the latter reaches the upper end of its stroke.
  • the clearance beneath the latch members 51 and 56 and the lower face of the ram 15 when such ram is at the top of its stroke is made as small as practicable in order that the descending ram will not attain an unduly high velocity before it impinges on one or the other or both of the latch members.
  • the latch members may be provided with hardened nose pieces 85 to receive the impact of the descending ram, and such nose pieces may project laterally from the latch members to be received in slots 86 in the guides 50 and 55, thus preventing rotation of the latch members in the guides.
  • the cam 27 will alternately raise the ram 15 and permit it to descend under the influence of gravity and the fluid pressure existing within the cylinder-accumulator 1820.
  • the ram 15 approaches the lower limit of its stroke, it first strikes the heads of the punches 35 to effect the piercing operation and then engages the stops 29, which limit its further descent.
  • the stops 29 are so positioned that the ram will engage them before the roller 28 on the ram can come into contact with the cam 27.
  • the cam 46 operates to lift the fingers 42 and restore the punches to raised position.
  • the feed slide 62 which was in retracted position when the ram began its descent, advances to feed a link plate from the magazine and to cause'ejection of the plate just pierced.
  • the cam 70 operates to move it into retracted position before the ram begins its next descent.
  • the lever 57 can be operated to advance the latch member 56 and retain the ram in elevated position and simultaneously to lock the arm '71 in a position which will retain the feed-slide 62 retracted. If it should be desired to interrupt reciprocation of the ram while permitting the feeding mechanism to remain in operation the latch member 51 instead of the latch member 56 can be advanced to retain the ram in elevated position.
  • Shearing velocity can be changed by varying the ram weight or stroke or, in a particular set-up, by adjusting the air pressure.
  • a series of experimental operations were run on the machine described above, using different ram velocities and different die clearances, with the following results.
  • the holes produced in the link plates had smoother walls and less taper than those produced by conventional punching equipment, and it was readily possible to produce holes which were substantially free from taper and had smooth walls comparable to or even better than those produced by conventional punching followed by a secondary shaving operation which removes a few thousandths of an inch of metal from the wall of the pierced hole.
  • Substantially narrower clearances could be used between the high velocity punch and its die than are required on conventional presses piercing corresponding holes in corresponding material.
  • conventional die clearances on the link plate material used are of the order of 6% of the stock thickness, or about .005" each side, for .080" stock.
  • We operated the high velocity machine satisfactorily with clearances of the order of .001" on each side or .002 on the diameter. Both clearance width and ram velocity affects hole shape and size.
  • an increase in punch velocity from 358 to 690 feet per minute increased hole diameter from .2740 to .2745 inch with the same tools.
  • the link plates being punched were of the type used in power transmission chain, in which the load is transmitted from link to link by the bearing contact between the hole walls of the link plates and the pins received in such holes. It will be understood that the smoothness and straightness of the hole walls have a critical influence on the area and character of the bearing surface available to transmit the load.
  • a punch press employing our invention has other substantial advantages.
  • a press having the specifications set forth above is capable of performing punching operations which would require a 13- ton punch press of conventional type.
  • the machine is therefore much lighter in weight and occupies considerably less floor space.
  • the ram-guiding means is not subjected to the side loads and wear which result from inclination of the connecting rod or link in presses of the conventional type.
  • the shearing machine shown in FIGS. 7-11 is one adapted to cut pins of predetermined length from intermittently fed stock in the form of a rod or wire.
  • the stock-feeding means which is of known type, comprises a stationary stock-clamp 91 and a second clamp 92 which reciprocates over a path parallel to the stock 90.
  • a stationary stock-clamp 91 and a second clamp 92 which reciprocates over a path parallel to the stock 90.
  • the clamp 92 During the forward or feeding stroke of the clamp 92 such clamp is closed to grip the stock, while the clamp 91 is released, with the result that the stock is fed forwardly into a shear 93.
  • the reverse stroke of the clamp 92 it is re leased while the clamp 91 is closed to hold the stock in fixed position as the shear operates to sever a pin.
  • .piston is mounted in stationary position.
  • the stroke of the reciprocating clamp 92 . is of controlled length corresponding to the length of the pins to be cut from the stock.
  • the clamps 91 and 92 and the shear 93 may all be supported from a base 94 and operated by a common, continuously rotating drive shaft 95 extending along the rear of the base.
  • the particular shear shown in the drawing comprises a stationary shear-member 96 and a horizontally reciprocating shear member 97, respectively carrying abutting bushings 98 and 99 of hard material which receive the stock and perform the shearing operation. Both of the shear members are mounted in a block 100 supported in fixed position from the base 94. As shown, the movable shear member 97 is received between upper and lower wear shoes 101 (FIG. 8) in the block 100 and is acted on by a third shoe 102 urged by springs 103 in a direction to maintain the adjacent ends of the bushings 98 and 99 in abutting relationship, as indicated in FIG. 10.
  • a compression spring 104 acts on the movable block 97 to urge it toward a position, determined by engagement of a flange 105 on the block with the shoes 101, in which the openings in the bushings 98 and 99 are in alignment with each other to permit the stock 90 to enter the bushing 99 during the feeding stroke of the clamp 92.
  • the movable cutting element in this case the movable block 97, is
  • FIGS. 7-11 diifers from that of FIGS. 1-6 in that the cylinder, which, in part contains the body of pressurized gas, is formed in the reciprocating ram, while the associated Other differences between the two machines reside in the means employed to retract and release the ram and in the use of the spring 104 to retract the movable cutting element.
  • the shear 93 is mounted on a plate 110 provided, in rear of the shear, with spaced, upwardly extending front and rear posts 111 and 112.
  • the front post slidably receives the ram 113, which is provided at its front end with a centrally located boss 114 adapted to engage the movable shear member 97.
  • the ram 113 is provided with a centrally located cylindrical recess 116 constituting a cylinder which receives a piston 117 mounted in fixed position on and projecting forwardly from the rear post 112.
  • An axial passage 118 extending through the piston 117 connects the cylinder 116 with a passage 119 extending upwardly through the rear post 112 and communicating at its upper end with an accumulator 120.
  • a supply of gas under pressure is maintained in the accumulator 120 and cylinder 116, as by the means employed for the purpose in the machine of FIGS. l-6.
  • the passages 118 and 119 should have as large a cross-sectional area as practicable in order to avoid throttling of gas displaced between the cylinder 116 and the accumualtor 120.
  • a reciprocable yoke 121 comprising a front member 122 and a rear member 123 rigidly interconnected by shouldered bolts 124 slidably received in the rear post 112.
  • the ram 113 is loosely received in the front yoke member 122, whose rearward movement relative to the ram is limited by its engagement with an abutment in the form of an annular flange 126 provided at the rear end of the ram.
  • the yoke is reciprocated in timed relation with the stock-feeding mechanism by means of an eccentric 127 carried by the drive shaft 95, such eccentric being received in the rear end of a connecting rod 128
  • a connecting rod 128 Whose front end is pivotally connected to the rear yoke-plate 123, as by a pin 129.
  • a latch 131 pivotally mounted in the rear post 112 and adapted to engage the ram-flange 126 and retain the ram in retracted position until the latch is released.
  • a spring 132 resiliently urges the latch toward engagement.
  • it is provided with an upwardly projecting tail 133 located in the path of movement of a pin 134 projecting forwardly from the rear yoke-plate 123.
  • FIG. 11 the parts of the shearing mechanism are shown in the positions they occupy at the completion of a shearing operation.
  • the yoke 121 is at the forward limit of its movement, as is also the ram 113, which has struck the movable shear member 97 and driven it forwardly to shear the stock and compress the spring 104.
  • the front yoke plate 122 is spaced forwardly from the ram-fiange 126 to prevent it from interfering with the forward movement of the ram 113 under the influence of pressure in the cylinder 116.
  • the yoke 121 In the rotation of the drive shaft, the yoke 121 is moved rearwardly, bringing the front yoke plate into engagement With the ram flange 126, retracting the ram, and permit ting the spring 104 to restore the movable shear-member 97 to its normal position (FIG. 10) in which the bushings 98 and 99 are aligned.
  • the ram-flange 126 clears the latch 131, which is then moved upwardly by the spring 132 into engaging position in front of the ram flange.
  • the pin 134 on it strikes the latch-tail 133 and releases the latch, thereby permitting the ram to move forwardly under the accelerating influence of the pressurized gas in the cylinder 116, strike the movable shear-member 97 and drive it through its cutting stroke.
  • Forward movement of the ram is limited by a pad 136 of rubber or like resilient material secured to the rear face of the block 100, while a similar pad 137 mounted in the block 100 limits forward movement of the shear-member 97.
  • the pin shearing machine of FIGS. 7-11 is a true shearing machine in which the stock is stressed in shear to the point of fracture by dies which move in a direction to pass each other with a close clearance.
  • the pin shearing machine like the punching machine, produces materially better results than are obtainable on conventional shearing presses.
  • Conventional machines tend to produce pin ends which are deformed by plastic deformation and which have an objectionable rounded corner or radius where the shearing cut began that merges into a crescent-shaped cut band where the tool has penetrated the cross-section before fracture occurred, and on which the major portion of the end face is an oblique fracture surface.
  • the high velocity shearing will produce pin blanks which meet high quality standards without requiring secondary end-finishing operations, in sizes which it was not possible to produce to the same standards by conventional shearing, and which required more expensive sawing or screw-machine operations.
  • a shearing machine such as that of FIGS. 711 will depend upon the effort required to perform the shearing operation.
  • a production machine in accordance with the invention may utilize the following representative values:
  • a reciprocable ram movable over a predetermined path into and out of engagement with the movable shearing element, means constantly urging said ram toward engagement with the movable shearing element, said means comprising a cylinder and piston one of which is movable with the ram, a rotatable shaft, means including a cam carried by said shaft and operable in rotation thereof to move the ram to a retracted position spaced from said movable shearing element and then to release it to permit fluid-pressure in said cylinder to force the ram toward engagement with said movable shearing element, means for maintaining fluid pressure in said cylinder sufiicient to accelerate the ram to a velocity such that, upon striking the moving shearing element following its release, it will cause the movable shea
  • a machine as set forth in claim 1 further characterized in that the volume of said cylinder is many times the displacement of said piston.
  • a machine as set forth in claim 1 with the addition of means operated in timed relation with said shaft for feeding work into position to be operated on by said shearing elements and means for interrupting operation of said feeding means while said shaft continues to rotate.
  • a machine as set forth in claim 1 with the addition of means operated in timed relation with said shaft for feeding work into position to be operated on by said shearing elements.
  • a machine as set forth in claim 1 with the addition of means operated in timed relation with said shaft for feeding work into position to be operated on by said shearing elements and means operable to simultaneously retain the ram in retracted position and interrupt operation of said feeding means.
  • a machine as set forth in claim 9 in which the latch is released in response to movement of the cam to said lost-motion-providing position.
  • a reciprocable ram movable over a predetermined path into and out of engagement with said movable shearing element, means constantly urging said ram toward engagement with said movable shearing element, power-operated means for moving the ram against the effort exerted on it by said ram-urging means to a retracted position spaced from said movable shearing element and then releasing it to permit said ram-urging means to force the ram toward engagement with the movable shearing element, said ram urging means exerting on the ram a force sufiicient to impart to the ram before it engages the movable shearing element a kinetic energy at least equal to that required both to accelerate the movable shearing element to a velocity of at least 6 to 8 feet
  • a shearing machine as set forth in claim 11 with the addition of means operable in timed relation with said power-operated means for feeding work into position to be sheared by the shearing elements, and means for interrupting operation of said feeding means while said power-operated means continues in operation.
  • a reciprocable ram movable over a predetermined path into and out of engagement with the movable shearing element, means constantly urging said ram toward engagement with the movable cutting element, said means comprising a cylinder and piston one of which is movable with the ram, means to move the ram to a retracted position spaced from said movable shearing element and then to release it to permit fluid-pressure in said cylinder to force the ram toward engagement with said movable cutting member, means to maintain fluid pressure in said cylinder sufficient to accelerate the ram to a velocity to impart to the moving shearing member, upon striking the same following its release, a velocity of at least 6 to 8 feet per second to cause the movable shearing element to perform the cutting operation, and means operating in timed
  • a reciprocable ram movable over a predetermined path into and out of engagement with the movable shearing element, resilient means constantly urging said ram toward engagement with the movable shearing element, a rotatable shaft, means including a cam carried by said shaft and operable in rotation thereof to move the ram to a retracted position spaced from said movable shearing element and then to release it to permit said resilient means to force the ram toward engagement with said movable cutting member, said resilient means being stressed to maintain a force on said ram sufficient to impart to it before it engages the movable shearing element a kinetic energy at least equal to that required both to accelerate the movable shearing element to a velocity of at least 6 to 8 feet per second and to cause the movable
  • a reciprocable ram for driving the movable shearing element through the shearing operation, resilient means urging said ram in a shear actuating forward direction, power-operated means for moving the ram against the effort exerted on it by said resilient means to a retracted position and then releasing it to permit the resilient means to force the ram forward to drive the movable shearing element through a shearing operation
  • said resilient means exerting on the ram a ram-accelerating force suflicient to impart to the ram before the shearing operation begins a kinetic energy sufficient to cause the movable shearing element to perform the shearing operation at an initial velocity of at least 6 to 8 feet per second, and means for retracting the movable shearing element to a work-piece
  • a shearing machine as set forth in claim 25 in which said resilient means comprises an expansible gas chamber in which the gas pressure acts to urge the ram forward, and means to maintain said chamber under elevated pressure to exert continuous ram-urging force.

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3665794A (en) * 1970-03-23 1972-05-30 Littell Machine Co F J Apparatus for positioning scroll shaped metal strips
US3735656A (en) * 1971-05-12 1973-05-29 Hjo Mekaniska Verkstad K & V Arrangement in and relating to high speed impact cold planar flow shearing apparatus
US3905258A (en) * 1972-10-04 1975-09-16 Novex Rt Method of and apparatus for high speed shearing off of workpieces

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US423119A (en) * 1890-03-11 Punching-machine
US655267A (en) * 1900-02-03 1900-08-07 Alexander Obermeyer Machine-tool for punching, stamping, &c.
US957942A (en) * 1908-05-12 1910-05-17 Francis R Eden Cutting or trimming machine for sheet metal.
US1431651A (en) * 1921-10-17 1922-10-10 Sigmund L Goldman Bottle-capping device
GB279229A (en) * 1926-09-27 1927-10-27 Richard Johnson & Nephew Ltd Improvements relating to the production of dies for wire drawing
US1859372A (en) * 1929-09-30 1932-05-24 A & H G Mutschler Inc Feeding apparatus
US1983842A (en) * 1933-08-18 1934-12-11 Drucker Abraham Cutting press
GB428674A (en) * 1933-11-29 1935-05-16 Fernand Beaudouin Metal punching, rivetting and rivet removing machine
US2039840A (en) * 1933-12-14 1936-05-05 Charles H Howland-Shearman Method for causing cold flow in substances
US2602507A (en) * 1946-03-01 1952-07-08 Adams Ida Nichols Tool press and operating means therefor
US2708970A (en) * 1951-01-26 1955-05-24 Wales Strippit Corp Punch holder with controllable lifting spring
US2850093A (en) * 1955-12-06 1958-09-02 Roto Bag Machine Corp Perforating apparatus
US2956464A (en) * 1955-09-29 1960-10-18 Emhart Mfg Co Notching press with work indexing means and tool disabling means
US3096015A (en) * 1960-01-27 1963-07-02 Scm Corp Ball perforator

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US423119A (en) * 1890-03-11 Punching-machine
US655267A (en) * 1900-02-03 1900-08-07 Alexander Obermeyer Machine-tool for punching, stamping, &c.
US957942A (en) * 1908-05-12 1910-05-17 Francis R Eden Cutting or trimming machine for sheet metal.
US1431651A (en) * 1921-10-17 1922-10-10 Sigmund L Goldman Bottle-capping device
GB279229A (en) * 1926-09-27 1927-10-27 Richard Johnson & Nephew Ltd Improvements relating to the production of dies for wire drawing
US1859372A (en) * 1929-09-30 1932-05-24 A & H G Mutschler Inc Feeding apparatus
US1983842A (en) * 1933-08-18 1934-12-11 Drucker Abraham Cutting press
GB428674A (en) * 1933-11-29 1935-05-16 Fernand Beaudouin Metal punching, rivetting and rivet removing machine
US2039840A (en) * 1933-12-14 1936-05-05 Charles H Howland-Shearman Method for causing cold flow in substances
US2602507A (en) * 1946-03-01 1952-07-08 Adams Ida Nichols Tool press and operating means therefor
US2708970A (en) * 1951-01-26 1955-05-24 Wales Strippit Corp Punch holder with controllable lifting spring
US2956464A (en) * 1955-09-29 1960-10-18 Emhart Mfg Co Notching press with work indexing means and tool disabling means
US2850093A (en) * 1955-12-06 1958-09-02 Roto Bag Machine Corp Perforating apparatus
US3096015A (en) * 1960-01-27 1963-07-02 Scm Corp Ball perforator

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3665794A (en) * 1970-03-23 1972-05-30 Littell Machine Co F J Apparatus for positioning scroll shaped metal strips
US3735656A (en) * 1971-05-12 1973-05-29 Hjo Mekaniska Verkstad K & V Arrangement in and relating to high speed impact cold planar flow shearing apparatus
US3905258A (en) * 1972-10-04 1975-09-16 Novex Rt Method of and apparatus for high speed shearing off of workpieces

Also Published As

Publication number Publication date
FR1429541A (fr) 1966-02-25
DE1502680A1 (de) 1969-11-20

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