US3672250A

US3672250A - Cutting press having improved means for handling cut product

Info

Publication number: US3672250A
Application number: US48567*A
Authority: US
Inventors: David F Creffield
Original assignee: USM Corp
Current assignee: USM Corp
Priority date: 1970-04-27
Filing date: 1970-04-27
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27

Abstract

A cutting press having a beam and a bed arranged for relative movement of approach and separation is provided with improved means for handling the cut product. The product handling means includes a product feed table and a stacking device having a vertically movable table and control means operative in response to engagement of the upper surface of the stack with sensing means adjacent the under side of the feed table to terminate upward movement of the table of the stacking device.

Description

United States Patent Creffield [54] CUTTING PRESS HAVING IMPROVED MEANS FOR HANDLING CUT PRODUCT David F. Creffield, Bristol, England [73] Assignee: USM Corporation, Boston, Mass.

[22] Filed: April 27, 1970 [21] Appi. No.: 48,567

[72] Inventor:

Related US. Application Data [62] Division of Ser. No. 682,953, Nov. 14, 1967, Pat. No.

[52] [1.5. CI ..83/92, 83/94, 83/277 [51] Int. Cl ..B65h 31/10 [58] Field ofSearch ..83/86, 90,9l,92,94, 277

[15] 3,672,250 [451 June 27, 1972 [56] References Cited UNITED STATES PATENTS 3,406,602 10/1968 Creffield ..83/92 3,219,338 11/1965 Kastner et al ..83/92 X Primary Examiner-James M. Meister Attorney-W. Bigelow Hall, Richard A. Wise and George C. Fuller [57] ABSTRACT A cutting press having a beam and a bed arranged for relative movement of approach and separation is provided with improved means for handling the cut product. The product handling means includes a product feed table and a stacking device having a vertically movable table and control means operative in response to engagement of the upper surface of the stack with sensing means adjacent the under side of the feed table to terminate upward movement of the table of the stacking device.

5 Claims, 18 Drawing Figures PATfNTEnJuaz? m2 sum 02 or 10 MM U PATENTEDJUNZ'! we saw on or 10 PATENTEnJum 1912 sum as or 10 PATENTEDJum I972 3.672.250

sum as or 10 PATENTEDJUNQT I972 sum 10 or 10 \N am n A wk CUTTING PRESS HAVING IMPROVED MEANS FOR HANDLING CUT PRODUCT This is a division of application Ser. No. 682,953, filed Nov. 14, l967 in my name, now U.S. Pat. No. 3,527,132, issued Sept. 8, 1970.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improvements in apparatus for cutting sheet material and more especially to improvements in apparatus relating to assemblies for cutting sheet material of the type disclosed in U.S. Pat. No. 3,406,602, issued Oct. 22, 1968 in my name.

2. Description of the Prior Art In the aforementioned patent there is described apparatus for cutting sheet material comprising (i) a press having a beam and a bed which is mounted for movement towards and away from the beam whereby sheet material fed therebetween is cut by cutting means in the form of a cutting die mounted on the beam, (ii) a feed table arranged to move between a retracted position, in which an outfeed portion of the table is positioned between the beam and the bed, and an advanced position, in which an infeed portion of the table is so positioned and the outfeed portion is beneath a rearward extension of the press beam, (iii) means mounted on the feed table for clamping the sheet material against the feed table when the table is moved from its retracted to its advanced position, (iv) a clamping member which is supported on the rearward extension of the beam of the press and extends widthwise of the feed table, this clamping member being spring urged downwardly to engage the sheet material on the feed table therebeneath whereby, when the feed table is moved from its advanced to its retracted position, to restrain the sheet material from movement with the table, and (v) a stacking device disposed beneath the rearward extension of the press beam for receiving cut portions of the sheet material from the outfeed portion of the feed table when the table is moved from its advanced to its retracted position.

The stacking device referred to above comprises a stacking table which is movable heightwise with the press bed, in the operation of the apparatus, and also relative to the bed, upward movement of the stacking table being arrested by engagement of the upper surface thereof, or of the upper surface of a stack of cut portions supported thereon, with the undersurface of the outfeed portion of the feed table (which at this time is in its advanced position) with a result that in successive operations of the apparatus the upper surface of the stacking table, or the upper surface of a stack of cut portions supported thereon, is brought to the same, or substantially the same, heightwise position to receive a cut portion thereon when the feed table is moved from its advanced to its retracted position.

It is one of the various objects of the present invention to provide an improved assembly of the type referred to above wherein the pressure exerted by the stacking table against the under-surface of the feed table upon engagement therebetween to arrest the upward movement of the stacking table is reduced or eliminated.

SUMMARY OF THE INVENTION There is herein described, to illustrate the invention by way of example, apparatus for cutting sheet material from a supply of indefinite length, which is generally similar, except as hereinafter described to that described in the aforementioned patent, comprising a press having a stationary beam provided with a rearward extension, and a bed movable towards and away from the beam, a feed table arranged to move between a retracted position, in which an outfeed portion thereof is positioned between the beam and the bed of the press, and an advanced position, in which an infeed portion of the feed table is positioned therebetween and an outfeed portion is positioned beneath the rearward extension, and a stacking device disposed beneath the rearward extension of the press beam and arranged to receive cut portions of sheet material from the feed table when the latter is moved from its advanced to its retracted position, a clamping member being mounted on the feed table for clamping the sheet material to the feed table as the table moves from its retracted to its advanced position, and sheet material being restrained from moving with the feed table as it moves from its advanced to its retracted position.

In the operation of the illustrative apparatus, sheet material to be cut is clamped on the feed table, on the infeed portion thereof, with the feed table in its retracted position. The feed table then moves to its advanced position to carry the material to be cut between the beam and the bed of the press, a portion of sheet material cut during a previous operation of the press being carried on the outfeed portion of the feed table from between the beam and the bed to a position beneath the rearward extension of the beam and above the stacking device. The bed of the press is then raised whereby the sheet material is cut and also a stacking table of the stacking device is raised and its heightwise position is determined by engagement with the under-surface of the feed table. After the cutting operation the press bed is lowered a small distance, e.g. one-eighth inch, to relieve the pressure applied between the beam and the bed while maintaining the sheet material in frictional engagement with the beam and die mounted thereon. The clamping member is then released and the feed table moved to its retracted position while the sheet material is restrained from movement therewith, the cut portions beneath the rearward extension of the beam being thus deposited on the stacking device.

As in the apparatus described in the aforementioned patent, the stacking device of the illustrative assembly is arranged to cooperate with the feed table, the stacking table thereof being movable upwardly towards the feed table (after the latter has been moved to its advanced position), when the bed of the press is moved towards the beam, until the upper surface of the stacking table, or of a stack of cut portions supported thereon, engages with the under-surface of the feed table, thereby determining in each cycle of operation of the illustrative assembly the heightwise position of the stacking table relative to the feed table for receiving a further cut portion from the latter subsequently in the cycle of operation, sensing means being provided on the under-surface of the feed table whereby, upon engagement thereof by the upper surface of the stacking table, or of a stack of cut portions supported thereon, further upward movement of the stacking table is prevented.

The stacking device of the illustrative apparatus is generally similar to the stacking device described in the aforementioned application and comprises a support which is mounted for heightwise movement with the bed of the press and on which the stacking table is supported for heightwise movement relative thereto. The support also carries a hydraulic cylinder on a piston rod on which is supported a sprocket arranged to engage with a chain extending between the stacking table and a fixed base portion of the press, so that as the bed of the press is raised, thereby raising also the support of the stacking device and the hydraulic cylinder, the stacking table is raised relative to the support at the same rate.

The sensing means provided on the under-surface of the feed table comprises a plurality of (viz. six) sensors in the form of fluid logic devices, any one of which is responsive to engagement thereof by the upper surface of the stacking table, or of a stack of cut portions supported thereon, to transmit a signal through an amplifier to operate a hydraulic valve which is effective to exhaust fluid from the end of the hydraulic cylinder remote from the sprocket to allow the sprocket, and thus also the stacking table, to move downwardly relative to the support during continued upward movement of the latter together with the press bed, so that as the height of the stack of cut portions fed in successive cycles of operation of the assembly on to the stacking table increases, the heightwise position of the stacking table relative to the support is progressively lowered. As an alternative to merely allowing pressure fluid to exhaust from the cylinder, the hydraulic circuit may be so arranged that in addition pressure fluid is admitted to the opposite end of the cylinder whereby positively to drive the sprocket downwardly relative to the support.

The feed table of the illustrative apparatus comprises two support bars extending forwardly and rearwardly of the apparatus over a large proportion of the length thereof, grooves being provided therefor in the press bed and the bars being yieldingly supported therein on spring-urged rollers. The support bars carry a hardened steel plate, which constitutes the infeed portion of the feed table and against which the sheet material is cut, a synthetic material plate which constitutes the outfeed portion of the feed table, and a further plate (made for example of polymethyl methacrylate), which constitutes a separator member.

The illustrative apparatus further comprises a plurality of (viz. 10) supports for rolls constituting the supply of sheet material, the rolls being supported along a conveyor which is advanced step-by-step in timed relation with the operation of the press of the assembly. Provision is made for a lazy loop of material between the conveyor and the feed table and electrical control means in the form of two microswitches (acting as upper and lower indicator switches for a carrier for the lazy loop) is provided whereby, when the illustrative assembly is in use, a cycle of operation thereof can only be initiated when a lazy loop is provided therein.

In addition the feed table is no longer required to be of as robust a construction as that of the assembly described in the aforementioned application, since it no longer serves to resist the force of the stacking table (as determined by a hydraulic relief valve) but carries sensing means for controlling the movement of the stacking table.

It will of course be realized that the illustrative apparatus herein described has been selected for description by way of exemplification of the invention and not by way of limitation thereof.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described further in connection with the attached drawings in which:

FIG. 1 is a left elevation of apparatus including a press, feed table, conveyor and stacking device thereof embodying the present invention;

FIG. 2 is a front elevation partly in section on an enlarged scale of a portion of the apparatus of FIG. 1 and illustrating die supporting mechanism;

FIGS. 3, 4 and 5 are partial views of the die supporting mechanism;

FIG. 6 is a rear elevation with parts broken away, of the apparatus of FIG. 1, showing the stacking device thereof;

FIG. 7 is a front elevation of the illustrative apparatus, on an enlarged scale and with parts broken away, showing the feed table, a sheet material clamping member thereof (in a position in which it is held during retraction of the feed table), and means on the press beam for controlling the extent of retracting movement of the feed table;

FIG. 8 is a left elevation, with parts broken away, of parts shown in FIG. 7;

FIG. 9 is a plan view, with parts broken away, of a rear portion of the apparatus of FIG. 1;

FIG. '10 is a left elevation of said rear portion on an enlarged scale and with parts broken away;

FIG. 1 1 is a partial rear elevation, partly in section, showing parts illustrated in FIG. 10;

FIG. 12 is a fragmentary view, on an enlarged scale, of a fluid logic sensing head of the illustrative apparatus;

FIG. 13 is a diagrammatic representation of the fluid logic, pneumatic and hydraulic circuits of the stacking device of the illustrative apparatus;

FIG. 14 is a partial side elevation, on an enlarged scale, of the illustrative apparatus showing separator means of the illustrative apparatus;

FIGS. 15 and 16 are partial views showing said separator means at different stages in a cycle of operation;

FIG. 17 is a partial section, on an enlarged scale, of the illustrative apparatus showing one of four die locating means for use in a die loading operation; and

FIG. 18 is a diagrammatic representation of an electrical control circuit of the illustrative apparatus.

GENERAL ARRANGEMENT Referring to FIG. 1, the illustrative apparatus, which is generally similar to the apparatus described in the abovementioned patent, is adapted for use in cutting sheet material from a supply of indefinite length. It comprises a moving bed toggle press generally designated 30, a feed table generally designated 32 movable forwardly and rearwardly of the press, a conveyor generally designated 34 arranged at the front of the press for feeding sheet material on the feed table, and a stacking device generally designated 36 disposed at the rear of the press for receiving cut portions of sheet material from the feed table.

Referring now also to FIGS. 2 5, the press 30 comprises a bed 38 movable heightwise on four pillars 40 towards and away from a beam 42 on which is supported a die K comprising a steel backing plate 44 on which is mounted a plywood block 46 for supporting blade portions 48; ejector members 50 of a resilient synthetic material are provided within the areas defined by the blade portions whereby cut material is ejected therefrom. The beam is provided at both its front and rear sides, extending along the length thereof, with brackets 52 to which is secured a hardened ground steel plate 54 covering the whole area of the beam and constituting a die engaging surface thereof. The plate 54 is secured to the brackets by a plurality of screws 56 which pass through the brackets and the plate and have threaded on to depending shank portions thereof peg members 58 which also serve to cooperate with correspondingly positioned apertures 60 formed in the backing plate 44 of the die thus to receive the die in a predetermined relation on the press beam.

FEED TABLE The feed table 32 is in the form of a composite member comprising an infeed portion, in the form of a hardened steel cutting plate 104 on which sheet material is supported during a cutting stroke of the press of the illustrative assembly, an outfeed portion, in the form of a plate 106 of synthetic material which receives cut portions of sheet material and transfers them to the stacking device, and a separator member, in the form of a clear plastic plate 108, which will be referred to hereinafter. The three

plates

104, 106, 108 are mounted on two support bars 1 10 extending fore and aft of the illustrative assembly so as to provide a continuous surface. The bars 110 are supported in grooves 112 formed in the press bed 38, rolls 1 14 being provided in recesses 1 16 formed in the grooves and projecting upwardly into the grooves under the pressure of springs 1 18, so that the feed table is held clear of the press bed during movement fore and aft of the press but can be urged thereagainst during an operative stroke of the press.

Referring now also to FIGS. 7 and 8, secured to the front end portions of the two support bars 110 is a cross plate reinforced by a channel section cross bar 122 at each end of which is mounted an end plate 124 constituting a carriage on which are supported two rollers 126 which ride on rails 128 on support arms 130 secured to the front of the press bed 38 and extending forwardly therefrom.

The rear end portion of each of the support bars 1 10 is provided with a bracket 132 on which is carried a roller 134, the rollers 134 being arranged to ride on rails 136 mounted on further support arms 138 secured to the rear of the press bed 38 and extending rearwardly therefrom.

Furthermore the feed table 32 is supported centrally by means of four sets of rollers 140 supported on brackets two mounted on the front and two at the rear of the press bed 38.

The feed table 32 is thus supported for movement fore and aft of the illustrative assembly between an advanced position, in which the steel plate 104 lies beneath the press beam 42 and the plate 106 is disposed above the stacking device 36, and a retracted position, in which the plate 106 lies beneath the press beam. For effecting movement of the feed table there is provided in the press bed 38 to the right of center thereof, a hydraulic piston and cylinder arrangement CH1 to the piston of which is secured a forwardly extending piston rod 144, the front edge portion of the piston rod being fixed to a plate 146 secured to the cross bar 122 and depending therefrom.

The feed stroke of the feed table 32 is adjustable, for different sizes of workpieces to be cut from the sheet material, the maximum stroke being determined in relation to the size of the press beam and bed. Since the advanced position of the feed table is constant, in that successive feed strokes carry the sheet material to be cut to a determined position relative to the press beam 42 and die K mounted thereon, the retracted position is varied according to the desired length of feed stroke (corresponding to the size of the die). The pressure fluid admitted to the hydraulic piston and cylinder arrangement CH1 (FIG. 7) is controlled by a valve VH1 supported on the front of the press bed 38. The valve is operated by means of a cam block 148 mounted in a hollow member 150 of square cross-section accommodated in a bore 152 in the press bed and threadedly receiving a rearward end portion of the rod 154 secured at its forward end portion in the plate 146, a knob 156 being provided at the forward end of the rod 154. The position of the cam block 148 fore and aft is thus adjustable by turning of the knob 156 to vary the relative fore and aft positions of the member 150 and the rod 154.

The member 150 passes through a square aperture 158 formed in a flanged bush 160 clamped, by means of two clamp screws 162 passing through slots 164 formed in the bush to the front of the press bed for limited rotational movement thereon. Rotation of the bush 160 is effected by means of a handle 166 at the left hand side of the press connected to the disc by a link 168, rotation of the disc between a first and a second position being effective to move the cam block 148 between an operative position, in which during a return stroke of the feed table it engages a plunger 151 connected to the valve VH1, and an inoperative position.

Operation of the valve VH1 by the cam block 148 is effective not only to cause the movement of the feed table to its retracted position to be arrested but also causes the clamping member 90 to move from an inoperative position, away from the upper surface of the feed table, to an operative position.

The clamping member 90 comprises, as above stated, a hollow roller and is mounted on a rod 170 pivotally supported at either end by arms of bell crank levers 172 in turn pivotally mounted in lugs 174 secured to the end plates 124. The other arms of the bell crank levers 172 are pivotally connected to links 176 mounted for sliding movement transversely of the feed table in bearings 178 depending from the under-surface of the cross plate 120. Mounted to the left of center of the plate 146, depending from the cross bar 122, is a piston and cylinder arrangement CH2 a piston rod 179 secured to the piston of which carries a cross pin 180 to opposite ends of which are secured ends of two chains 181, each chain being secured at its other end, to one of the links 176. Movement of the piston rod 179 downwardly is thus effective, through the chains 181, to cause the clamping member 90 to be raised to its inoperative position, springs 177 action between the bearings 178 and the links 176 being effective to return the piston rod heightwise and thus also to move the clamping member to its operative position. In a cutting cycle of operation of the illustrative apparatus, the clamping member is in its operative position during a feed stroke of the feed table, i.e. during movement of the feed table from its retracted to its advanced position, a hydraulic valve (not shown) being provided whereby the clamping member 90 is caused to move to its inoperative position during a return stroke of the feed table.

STACKING DEVICE The stacking device 36 of the illustrative apparatus comprises a supporting frame comprising two vertical posts 182 secured on the rearward extending support arms 138 of the press and three cross struts 184 secured therebetween. The posts are slidable in linear bearings 186 supported in brackets 188 secured on a base portion 190 of the press. The cross struts 184 support a hydraulic piston and cylinder arrangement Cs1 a piston rod 192 secured to the piston of which carries a sprocket 194. Mounted for heightwise movement on rails 182s formed integral with the posts 182 are two rearwardly extending arms 196 connected to one another by cross rods 198 to form a stacking table, each arm 196 having secured at its front end a plate 200 on which are carried four rollers 202, the arrangement being such that two rollers run at either side of the rail 182:. A chain 204 is secured, at one end, to one of the cross rods 198 of the stacking table and, at the other, to the base portion 190 of the press. Thus upward movement of the press bed 38 is effective to raise the supporting frame of the stacking device 36 therewith and is also effective, through the sprocket 194 and chain 204, to cause the stacking table to be raised relative to the supporting frame, the arrangement being such that the distance moved by the stacking table is in a 2:1 ratio with the distance moved by the press bed.

Upward movement of the stacking table is limited by engagement of the upper surface of a pallet P or stack S of cut portionscarried thereby with the under-surface of the plate 106 of the feed table 32, which is in its advanced position when the press bed is caused to rise. For controlling the movement of the stacking table there is provided, as may be seen in FIG. 9, in recesses formed in the under-surface of the plate 106 six fluid logic sensing devices generally designated 206. Each sensing device 206 comprises a block 208 (FIG. 12) of synthetic material having an inlet bore 210 and an outlet bore 212 both of which open into a chamber 214 which is open to atmosphere through an aperture 216. The inlet bores 210 of the six devices are connected by small diameter pipes 218 to a manifold block 220 mounted on the undensurface of the plate 106 towards the rearward end thereof. Air under pressure is supplied to the manifold block 220 through a rigid pipe 222 which depends from the block and is connected through a recoil pipe 224 with an air source piped to a housing 225 for the fluid logic system of the illustrative assembly mounted on the rear of the press bed 38. The outlet bores 212 of the six devices are connected to small diameter pipes 226 which pass together inside a rigid large diameter pipe 228 depending from the plate 106 and inside a large diameter recoil pipe 230. The pipes 226 are connected to a turbulence amplifier arrangement TA (shown schematically in FIG. 13) as a single turbulence amplifier) and therethrough to a step up transformer SUT which controls a valve Vsl in the pneumatic circuit of the stacking device 36.

Referring now to FIG. 13, air under pressure is admitted through pipes Psl, PS2 to the valve Vsl and to a manually operable valve Vs2 respectively. When the illustrative assembly is at rest air will not be allowed to pass through either valve. When, however, the upper surface of a pallet P or stack S of cut portions is raised into engagement with the plate 106, the apertures 216 of the sensing devices are closed and thus a signal, in the form of an air pulse returned now along the outlet pipe 212, is transmitted to the turbulence amplifier TA, thereby upsetting the signal passing to the step up transformer SUT when the assembly is at rest. When no signal is transmitted to the transformer SUT the valve Vsl is opened to admit air under pressure to pipes Ps3, Ps4 thereby operating respectively three way valve Vs3, to shift it to the right viewing FIG. 13, and valve Vs4, to shift it to the left viewing FIG. 12. Operation of valve Vs4 in this manner exhausts pipe Ps5, connected to the opposite (right hand, viewing FIG. 13) side of the valve Vs3, to atmosphere. The valve Vs4, is normally spring urged to the right, thus to connect pipe Ps5, through pipe P56, with the manually operable valve Vs2.

Movement of the valve Vs3 to the right as aforesaid allows hydraulic fluid to be pumped to the upper side of the piston and cylinder arrangement Csl thereby causing the piston, and thus the sprocket 194 carried by the piston rod 192, to be lowered. The valve Vs3 is self-centering so that when the signal to the step up transformer SUT is again applied and admission of air under pressure through the valve Vs1 is prevented, the valve Vs3 assumes the position shown in FIG. 13, in which hydraulic fluid is admitted to neither side of the piston.

When the stack S of cut portions is full it is removed and thereafter the stacking table can be raised to its upper limit by operating the manually operable valve Vr2, air under pressure being then admitted through pipe Ps6, valve Vs4 and pipe Ps5 to the right hand side (viewing FIG. 13) of the valve Vs3 to shift it to the left. Hydraulic fluid is then admitted to the underside of the piston of the arrangement Csl to raise the piston rod 192 and sprocket 194, thereby, through the chain 204, raising the stacking table also.

The fluid logic system is so arranged that a signal from any one of the sensing devices 206 is effective to cause no signal to be transmitted to the transformer SUT.

In case it is desired to cause the stacking table to be lowered, a manually operable valve Vs7 is arranged in the fluid logic system, actuation thereof being effective to transmit a signal to the turbulence amplifier TA in the same manner as the sensing d evices 206.

CONVEYOR The conveyor 34 of the illustrative apparatus (FIG. 1) comprises an endless belt 258 which passes round drive rollers 260 (one only shown in FIG. 1) mounted in a frame 262 inclined at an angle of 30 to the horizontal. Mounted along the frame, at each side thereof, are 10 supports 264 (one only shown in FIG. 1), the supports being thus arranged in pairs of supporting rolls R of sheet material to be cut.

The frame 260 of the conveyor is supported at its rearward ends bytwo support structures 266 having in side view an H arrangement. The rearward ones of the uprights of these structures are longer than the forward ones and support between the upper ends thereof a roll of paper Rb which is fed into the press with the sheet material. Thus, a lay of sheet material to be cut comprises 10 layers of sheet material (e.g. cloth) and a layer of paper, whereby when the portions have been cut and stacked a layer of paper is interspersed between each 10 cut portions of sheet material.

Also supported in the structures 266, for heightwise movement therein, is a roller 268 supported at its ends by blocks 270 slidable in channels 272 formed in the structures, the arrangement being such that the 10 layers of sheet material pass round the roller 268 to the feed table thus forming a lazy loop in the material. The forward ends of the support bars 110 carry a roller 274 to facilitate feeding of the material from the lazy loop. When the roller 268 is in its lowermost position one of the blocks 270 trips a microswitch L814 mounted on the side of one of the channels. This switch has a normally closed part LS14a and a normally open part LS14b. At the start of a cycle of operation the feed table moves towards its advanced position and draws the material of the lazy loop thereby raising the blocks 270 and releasing the microswitch LS14. The normally closed part LSl4a is arranged in a conveyor motor M3 circuit and release thereof closes the circuit to cause the conveyor to be driven. Operation of this motor is arrested when the microswitch is again tripped.

Should it be that the conveyor does not operate as aforesaid upon movement of the feed table, the lazy loop roller 268 is carried to the top of the channels 272 and there trips a normally closed upper limit switch L816 also mounted on the side of one of the channels 272, which switc h breaks the circuit to the feed table, the latter being thus returned to its retracted position.

OPERATIONzCUTTlNG (SINGLE STROKE) When it is desired to operate the illustrative apparatus on single stroke cutting, the operator sets a selector switch 510, Slb, Slc to a position designated (1) in FIG. 18.

He then presses a normally open start switch P124 comprising two parts Pb4a, Pb4b. In single stroke cutting, part Pb4a is rendered inoperative. Closing part Pb4b of the start switch is effective, through a limit switch LS3 and a contact RL2b both normally in their positions shown in FIG. 18, the normally closed limit switch LS16, the part LS14b of the lazy loop lower limit switch held closed by one of the blocks 270, and a further normally closed limit switch LS15 (which is tripped to open when the stacking device has a full stack S of cut portions thereon), to make a circuit to a relay RLla and a solenoid SOL3 which is effective to cause the feed table 32 to move to its advanced position. Energization of relay RL1 closes normally open contacts RLla, RLlb thereby bypassing respectively the limit switches LS14b, LS15, and the start switch Pb4b, which latter can then be released. Since the limit switch LS14b is bypassed movement of the feed table is not arrested when it opens upon the lazy loop roller 268 being raised.

When the feed table has almost reached its advanced position, a normally open limit switch LS1 is momentarily tripped, thereby making a circuit to a relay RL3 and energizing two solenoids SOL10, SOL11 which operate a batch counter and a total counter respectively. Energization of the relay RL3 causes contacts RL3a, RL3b to move from their positions shown in FIG. 18 whereby a holding circuit to the relay RL3 is made through the contact RL3a, the selector switch Sla and a normally closed press bed upper limit switch LS5. When thereafter the feed table reaches its advanced position a normally open limit switch LS2 is closed which makes a circuit to a solenoid SOLl effective to cause the press bed to be raised. Raising of the press bed is effective to allow a press bed lower limit switch LS4 to move from its positions shown in FIG. 18.

When the press bed reaches the upper limit of its movement the normally closed switch LS5 is opened thereby de-energizing the solenoid SOLl, thus preventing further upward move ment of the bed, and the relay RL3, thus causing the contacts RL3a, RL3b to return to their positions shown in FIG. 18. A circuit is then made, through the limit switch LS3 normally held in the position shown in FIG. 18, the contact RL3a, limit switch LS4 and selector switch Slb, to the solenoid SOL2 whereby lowering movement of the press bed is initiated.

When the press bed has been lowered through a small distance such that the sheet material is still held in frictional engagement with the die K mounted on the press beam, the limit switch LS3 is tripped and moves from its position shown in FIG. 18 to break the circuit to the solenoid SOL2, to arrest the downward movement of the press bed, and make a circuit to a timer device TMR, which is set to allow a dwell period in said downward movement. In addition the movement of the limit switch as aforesaid breaks the circuit held through the contact RLlb, limit switch LS16 and contact RLla to the relay RL1 and to the solenoid SOL3 thus de-energizing them whereby the feed table is caused to be returned to its retracted position. Movement of the feed table is arrested by engagement of the cam block 148 with the valve VH1, which is effective to prevent further admission of hydraulic fluid to the piston and cylinder arrangement CH1 which drives the feed table and also to exhaust hydraulic fluid from the piston and cylinder arrangement CH2 to allow the clamping member to clamp the sheet material on to the feed table under the influence of the springs 177. The timer TMR is so set that the feed table is returned and the sheet material clamped as aforesaid before any further movement of the press bed is effected.

When the dwell period controlled by the timer TMR is completed, a normally open timer switch TMR] is closed thereby again making the circuit to the solenoid SOL2 and thus causing the downward movement of the press bed to be continued. The switch LS3 is thereupon returned to its position shown in FIG. 18. When the press bed reaches the lower limit of its movement, the limit switch LS4 is returned to its position shown in FIG. 18. and the circuit to the solenoid SOL2 is broken.

The cycle of operation of the illustrative apparatus is then completed. It will of course be understood that the stacking table of the stacking device moves with the press bed in the manner described above and a cut portion of sheet material is deposited on the stack S of cut portions when the feed table is retracted, as above described OPERATION AND CUTTING( AUTOMATIC) When it is desired to operate the illustrative apparatus in an automatic cutting mode, the operator sets the selector switch Sla, Slb, to a position designated (2) in FIG. 18. He also conveniently sets the batch counter to the number of cuts desired.

The operator starts the operation of the illustrative assembly in the same manner as for single cutting, viz. by pressing the start switch Pb4. The operation of the assembly then takes place in the same manner as for single cutting except as follows:

Pressing the, start switch Pb4a makes a circuit through the selector switch 810 with a relay RL4 and also a lamp LP3 to indicate that automatic cutting is selected. Energization of the relay RL4 causes normally open contacts RL4a, RL4b to be closed; a holding circuit through the contact RL4a is thus made to the relay RL4 bypassing the start switch. This holding circuit is maintained throughout the whole of the automatic cutting operation. In addition, when the lower limit switch LS4 is moved to its position shown in FIG. 18 at the end of each cutting stroke, it makes, through the limit switch LS3, contact RL3a, contact RLAb (held closed by the relay RL4), a batch counter operated switch B810 normally held in its position shown in FIG. 18, and limit switches LS16, SLl4b and LSlS, a circuit to the solenoid SOL3 whereby a new cutting cycle of operation is initiated.

Each time that the switch LS1 is tripped, as the feed table is moved to its advanced position, a pulse is transmitted to the batch counter. When the number of pulses equals the pre-set number the switch BS10 is moved from its position shown in FIG. 18 thereby breaking the circuit to the solenoid SOL3 and bringing the automatic cutting operation to an end. In addition it makes a circuit to a lamp LP2 to indicate that the operation is ended.

Having thus described by invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for cutting sheet material from a supply of indefinite length comprising, in combination, a press having a beam and a bed mounted for relative movement of approach and separation whereby sheet material fed therebetween is cut by cutting means supported on the beam, a feed table for feeding a portion of sheet material, after it has been cut by the cutting means, said table being movable between a retracted position in which an outfeed portion thereof is positioned between the beam and the bed of the press, and an advanced position in which said outfeed portion is positioned beneath a rearward extension of the press, means for restraining the cut portion of sheet material from movement with the feed table when said table is returned to its retracted position, and a stacking device disposed between the rearward extension of the beam for receiving the cut portion of sheet material as the feed table is returned to its retracted position, said stacking device comprising a stacking table movably upwardly toward the feed table only when relative movement of approach is effected between the beam and the bed of the press, sensing means operative to sense engagement between the under surface of the feed table and the upper surface of the stacking table or of a stack of cut portions supported therein, means controlled by said sensing means for terminating said upward movement of stacking table in response to the sensing of said engagement, and means responsive to said terminating means for u wardly moving said stacking table. I

2. n a press apparatus for cutting sheet material wherein the press comprises a beam and bed mounted for relative movement of approach and separation whereby sheet mate rial fed therebetween is cut by cutting means supported on the beam and a feed table for feeding a cut portion of sheet material out of the press, a stacking device for receiving the cut portion of sheet material from the feed table, the stacking device comprising a stacking table movable for approach and separation from the feed table, meanS disposed between the feed table and the stacking table for sensing engagement between the under surface of the feed table and the upper surface of the stacking table or a stack of cut portions supported thereon, the engagement occurring during approaching movement of the stacking table, means controlled by the sensing means and connected to the stacking table for terminating approaching movement of the stacking table in response to the sensing of the engagement and means for moving the stacking table.

3. Apparatus as defined in claim 2 in which the sensing means comprises a plurality of sensing devices mounted on the feed table and operative at a corresponding plurality of sensing locations adjacent the under surface of the feed table.

4. Apparatus as in claim 2 in which the means controlled by the sensing means for terminating approaching movement of the stacking table is responsive to sensing the engagement at any sensing location thereof for effecting termination of the approaching movement of the stacking table.

5. Apparatus as in claim 2 wherein the sensing means are fluidic logic sensing devices.

Claims

1. Apparatus for cutting sheet material from a supply of indefinite length comprising, in combination, a press having a beam and a bed mounted for relative movement of approach and separation whereby sheet material fed therebetween is cut by cutting means supported on the beam, a feed table for feeding a portion of sheet material, after it has been cut by the cutting means, said table being movable between a retracted position in which an outfeed portion thereof is positioned between the beam and the bed of the press, and an advanced position in which said outfeed portion is positioned beneath a rearward extension of the press, means for restraining the cut portion of sheet material from movement with the feed table when said table is returned to its retracted position, and a stacking device disposed between the rearward extension of the beam for receiving the cut portion of sheet material as the feed table is returned to its retracted position, said stacking device comprising a stacking table movably upwardly toward the feed table only when relative movement of approach is effected between the beam and the bed of the press, sensing means operative to sense engagement between the under surface of the feed table and the upper surface of the stacking table or of a stack of cut portions supported therein, means controlled by said sensing means for terminating said upward movement of stacking table in response to the sensing of said engagement, and means responsive to said terminating means for upwardly moving said stacking table.

2. In a press apparatus for cutting sheet material wherein the press comprises a beam and bed mounted for relative movement of approach and separation whereby sheet material fed therebetween is cut by cutting means supported on the beam and a feed table for feeding a cut portion of sheet material out of the press, a stacking device for receiving the cut portion of sheet material from the feed table, the stacking device comprising a stacking table movable for approach and separation from the feed table, meanS disposed between the feed table and the stacking table for sensing engagement between the under surface of the feed table and the upper surface of the stacking table or a stack of cut portions supported thereon, the engagement occurring during approaching movement of the stacking table, means controlled by the sensing means and connected to the stacking table for terminating approaching movement of the stacking table in response to the sensing of the engagement and means for moving the stacking Table.