US3527132A

US3527132A - Cutting press having improved means for clamping dies on the beam

Info

Publication number: US3527132A
Application number: US682953A
Authority: US
Inventors: David F Creffield
Original assignee: USM Corp
Current assignee: Emhart Enterprises Corp; USM Corp
Priority date: 1966-11-16
Filing date: 1967-11-14
Publication date: 1970-09-08
Anticipated expiration: 1987-09-08
Also published as: US3656380A; FR1557730A; GB1208104A; DE1660132A1

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 an improved separator means comprising separator elements and a plurality of independently yieldable support elements disposed above a table for receiving the cut product to urge separation of the cut product along cuts made by the press to lay the cut product on the table.

Description

United States Patent [72] Inventor David F. Cremeld Bristol, England 21 Appl. No. 682,953 [22] Filed Nov. 14, 1967 [45] Patented Sept. 8, 1970 [73] Assignee USM Corporation Flemington, New Jersey a corporation of New Jersey [32] Priority Nov. 16, 1966 33 Great Britain [31] 51,259/66 [S4] CUTTING PRESS HAVING IMPROVED MEANS FOR CLAMPING DIES ON THE BEAM 4 Claims, 18 Drawing Figs.

[52] U.S. Cl 83/698 [51] Int. Cl 826d 7/26 [50] Field of Search 83/698 [56] References Cited UNITED STATES PATENTS 2,984,176 5/l96l Sommer etal.... 83/698 3,027,792 4/l 962 Hohl 83/698 Primary Examiner-William S. Lawson AtmrneysW. Bigelow Hall, Richard A. Wise and George C.

Fuller. Aubrey C. Brine and Vincent A. White ABSTRACT: A cutting press having a beam and a bed arranged for relative movement of approach and separation is provided with improved means for die loading and unloading, for clamping dies on the beam, and for handling the cut product. The die clamping means is selectively operable to clamp dies from, or release them on, a feed table carried by the bed for quick and easy die changes. The product handling means includes improved separator means 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.

Patented Sept. 8, 1970 Sheet M we wfim Q C! WMM 0 n n w d% B lPMnte-d Sept. 8, 1970 Sheet @NN NNN w% mum Q Pmented Sept. 8, 1970 Sheet 3 of 10 Pahented Sept. 8, 1970 Sheet 9:5 5 .0. Eg Q:

a a a a as Patented Sept. 8, 1970 Sheet Patented Sept. 8, 1970 3,527,132

Sheet 6 of l0 Patented Sept. 8, 1970 3,527,132

Sheet 7 of 10 x 7 1 EDT Patented Sept. 8, 1970 Sheet .0 U U U U U fi V flwwwg wmmw @w v QM s. 3w 4. %\.w 3w QM 5 J 3% www mum 3T Q .P 3 g x Q; a Tu Patented Sept. 8, 1970 Sheet em 3 83 R @sx QM mm N Patented Sept. 8, 1970 Sheet wnm CUTTING PRESS HAVING IMPROVED MEANS FOR CLAMPING DIES ON THE BEAM 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. Letters Pat. No. 3,406,602, issued Oct. 22, 1968 in my name.

2. Description of the Prior Art In the aforementioned patent theae 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 under-surface 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 uppersu faceof the stacki ng tablefor the tipper iirface 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.

Furthermore, in the apparatus referred to above cutting dies are mounted on the under-surface of the beam manually, using toggle clamps to secure the die in position. If the die selected is to be used over a long period on a single production the time and effort on the part of the operator required for fixing it to the beam is relatively unimportant. If however it is desired to change dies frequently, it is desirable to reduce the time required thereby to a minimum.

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.

It is a further one of the various objects of the present invention to provide improved apparatus for cutting cut sheet material in which dies can be changed in a less time-consuming and operator-fatiguing manner.

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 posi' tioned between the beam and the bed of the press, and an ad vanced 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 out 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.

The illustrative press is further provided with means for detachably supporting a die on the beam, said means comprising two clamping bars mounted on opposite sides of the beam of the press and mounted for limited sliding movement along the length thereof between a loading position, in which a die can be brought into engagement with the beam, and a clamping position, in which the die is clamped on the beam, each clamping bar being provided with a plurality of (viz. four) slots, one end portion of each of which opens into the lower edge of the clamping bar to enable projections formed on a back plate of a die to be supported by the beam to pass into the slot. The die supporting means also comprises sensing means in the form of microswitches associated with the slots, tripping of the microswitches by engagement of the projections of the die therewith being effective to cause the clamping bars to move lengthwise of the beam from loading to clamping positions to clamp the die on the under-surface of the beam. The beam is also provided with die locating means in the form of depending pins which project into corresponding holes formed in the back plate of the die and thus also are effective to hold the die against movement lengthwise of the beam.

The illustrative apparatus also comprises electrical control means whereby selectively, instead of a cutting operation being effected upon initiation of a cycle of operation of the assembly, either a die supported on the beam can be unloaded on to the feed table or a die presented by the feed table can be loaded on to the press beam. Thus, when it is desired to unload a die, e.g. at the end of a series of cutting operations on a length of sheet material, the unload" electrical circuit is selected and a cycle of operation of the illustrative apparatus initiated. The feed table moves to its advanced position and thereafter the bed is raised to bring the feed table into engagement with the die. When the bed reaches the upper limit of its movement the clamping bars of the die supporting means are moved from their locking to their loading position and the die is released on to the feed table. The bed and thus the feed table are then lowered and the feed table, together with the die supported thereon, is returned to its retracted position. Similarly when it is desired to load a die on to the beam, the load circuit is selected. With the die to be loaded supported on the infeed portion of the feed table and located thereon by suitable die positioning means a cycle of operation is initiated and the feed table moves to its advanced position to carry the die beneath the press beam. The press bed is then raised together with the feed table to bring the die into engagement with the under-surface of the beam, the projections on the die back plate passing into the slots of the clamping bars, which at this time are in the loading position, and there tripping the microswitches to cause the clamping bars to move to their locking position to clamp the die in position. The bed and the feed table are then lowered and the feed table is returned to its retracted position. The illustrative apparatus is also provided with means whereby, when a die is to be loaded, the clamping member mounted on the feed table for clamping sheet material thereagainst is held in its inoperative position instead of being returned to its clamping position when the feed table returns to its retracted position, as in the case in a cutting cycle of operation of the assembly.

The load" electrical circuit of the illustrative apparatus is so arranged that the microswitches associated with either clamping bar must be tripped before the bar is moved as aforesaid. Furthermore when all the microswitches have been tripped, upward movement of the bed and the feed table is arrested. In this way a die can be loaded regardless of the depth thereof and thus damage to the die during loading is prevented.

The die positioning means whereby a die is located on the feed table prior to loading comprises a plurality of (viz. four) pegs supported on the clamping member of the feed table and arranged to be received in corresponding apertures formed in the projections on the die base plate, the pegs being withdrawn from the apertures when the die has been loaded as the bed of the press and thus the feed table are lowered 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 and which cooperates with a second separator member shaped complementarily thereto and supported on the rearward extension of the beam of the press to ensure that cut portions of sheet material are separated from the supply thereof when received by the stacking device, as the feed table moves from its advanced to its retracted position as aforesaid. Because of the complementary shapes of the two separator members, which shapes are the same as the cut portions to be separated thereby (and thus even the most intricate shapes are readily separable), a clean separation is achieved.

The second separator member is detachably mounted on the rearward extension of the press beam constituted by a plurality of (viz. four) rearwardly extending arms each having a plurality of spring urged members between any two adjacent ones of which a support block fixed on the second separator member can be received, whereby the second member is supported.

The illustrative apparatus further comprises a plurality of (viz. ten) 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.

The die supporting means of the illustrative apparatus is so constructed and arranged that instead of a single die, two separate dies can be supported on the beam side-by-side. Each of the two dies is provided with a plurality of (viz. two) projections at either side of its base plate for cooperating with two of the slots in either of the clamping bars, The die supporting means operates in a similar manner whether a single die or two dies side-by-side are presented thereto by the feed table.

Thus dies are readily changeable with a minimum of effort and time on the part of the operator. Furthermore because the feed table and press members used in carrying out a cutting operation are also utilized for loading and unloading operations, no additional mechanisms are employed to complicate the apparatus and render it more expensive.

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. 11 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 ofthe 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 iii are partial views showing said separator means at different stages in a cycle ofoperation;

FIG. 17 is a partial section, on an enlarged scale, ofthe 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 ofthe 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. 25, 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 ofthe 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.

DIE SUPPORTING MEANS For supporting the die K on the press beam 42 there is mounted for limited sliding movement on each of the brackets 52 a clamping bar 62 which has in cross-section the shape of an inverted L, slots 64 being provided in the horizontal portion of each clamping bar, through which slots screws 66 projecting upwardly from the plate 54 and bracket 52 pass, each screw being threaded into a securing block 68 against which the upper face of the horizontal portion of the clamping bar abuts. Apertures 70 are provided in the brackets 52 and accommodate springs 72 which serve to urge the clamping bars upwardly relative to the brackets 52 against the securing blocks 68.

Resiliently mounted at the right hand end of the front side of the press beam is a piston and cylinder arrangement Ccl a piston rod 74 secured to the piston of which carries a bracket 76 fixed to the clamping bar 62 slidably supported on the front side of the beam. A second piston and cylinder arrangement Cc2 is similarly mounted at the left hand end of the rear side of the press beam and has a piston rod 78 which is connected to the clampihg bar on the rear side of the beam through a bracket 80.

Each clamping bar 62 is provided with four horizontal slots 32 each provided, at the end thereof remote from the piston and cylinder arrangement, with a depending portion which opens into the lower edge of the bar. The slots are positioned on the clamping bars to correspond with projections 84 formed on the front and rear edges ofthe die backing plate 44 so that when a die is suitably located on the bed of the press and the bed is moved towards the beam, the projections 84 will enter the depending portions of the slots 82. An inclined face 82a joins the lower face of each slot with the face, nearer to the piston and cylinder arrangement, of its depending portion.

Associated with two of the four slots of the front clamping bar 62, viz. the second and fourth from the right, are two microswitches LS6, LS7 (see also FIG. 18) mounted on the clamping bar 62 and each provided with a downwardly spring urged plunger 86 which passes through an aperture 88 arranged in the clamping bar above its associated slot 82 and through apertures formed in the bracket 52 and plate 54 of the press beam, the plunger projecting below the plate 52 so as to be able to be engaged by the backing plate 44 of a die K presented to the beam as aforesaid. The rear clamping bar 62 similarly has associated therewith two microswitches LS8, LS9 (see FIG. 18) each provided with plungers 86.

In a cycle of operation of the illustrative apparatus for loading a die on to the press beam, a die K urged against the beam by the upward movement of the press bed first is effective to trip the microswitches LS6, LS7, LS8, LS9, whereupon the piston and cylinder arrangements Ccl, Cc2 are operated to cause the front and rear clamping bars to move to the left and right respectively, the inclined faces 82a engaging the projections 84 which have entered the depending portions of said slots and causing the die to be forced against the plate 54 under the pressure of the springs 72 urging the clamping bars 62 upwardly.

DIE LOCATING MEANS For locating a die K on the feed table 32 prior to presenting it for loading on to the press beam 42, the feed table has means provided on a clamping member 90 which operates, in a cutting operation of the illustrative assembly, to clamp sheet material to be cut against the feed table during a feeding stroke thereof. For supporting said means the clamping member 90, which comprises a hollow roller extending across the width of the feed table, is provided with grooves 92 cut away in the surface thereof at localities corresponding to the positions of the projections 84 formed on the die backing plate 44.

When a die is to be loaded, conveniently the operator places blocks 94 in the shape of an inverted U (FIG. 17) over the clamping member 90 and locates them in the grooves 92. The blocks 94 have rearwardly facing arms 96 which carry upstanding pins 98. The projections 84 are provided with apertures 100 for receiving the pins 98. Thus the die K to be loaded is located relative to the clamping member 90 and is carried into the press by the feed table. After the die K has been clamped against the plate 54 on the press beam as aforesaid, the press bed is lowered away from the beam, and thus the pins 98 are withdrawn from the apertures 100, prior to the feed table returning to its initial position.

For securing the blocks 94 against shifting during the operation of the illustrative assembly feet therefor may be provided by magnets 102.

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 110 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 114 being provided in recesses 116 formed in the grooves and projecting upwardly into the grooves under the pressure of springs 118, 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 120 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 110 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 advancedposition 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.

When it is desired to unload or load a die, it is necessary that, regardless of the length of the feed stroke of the feed table during previous cutting operations, the feed table be moved to its extreme retracted, i.e. forward, position (as determined by the maximum length of stroke of the hydraulic piston and cylinder arrangement CH1). In addition if any sheet material remains to be fed to the press, it is desirable that this should not be clamped to the feed table for the die loading or unloading operations. Thus when it is desired to load or unload a die, the operator moves the bush 160 to its second position to render the cam block 148 inoperative so that the feed table is retracted to its extreme forward position and the clamping member 90 remains in its inoperative position.

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 Csl a piston rod 192 secured to the piston of which carries a sprocket 194. Mounted for heightwise movement on rails 182: 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 182s. 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 portions carried 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 under-surface 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 Ps1, 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 V53, 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 PsS, through pipe Ps6, with the manually operable valve V32.

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 Crl thereby causing the piston, and thus the sprocket 194 carried by the piston rod 192, to be lowered. The valve V53 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 Vsl 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 Vs2, 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 I94, 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 devices 206.

SEPARATOR MEANS The beam 42 of the illustrative press is provided with a rearward extension in the form of four rearwardly extending support arms 232 (two only shown in FIG. 9) carried on the rear side of the press beam and supported by stays 234 thereon. The four arms are of the same construction and one only will now be described.

Each arm 232 has in cross-section the shape of an inverted U and receives therein eleven support elements 236 of hollow section mounted in the arm 232 end to end. Associated with each element 236 the arm 232 has a boss 238 extending up wardly from the top of the arm for receiving a headed pin 240 the shank of which passes into the element 236 and abuts, at its lower end, against the inner surface of the bottom of the element. A countersunk screw 242 passes through an aperture in the bottom of the element and is threadedly received in a bore formed in the lower end portion of the pin shank so that the element is clamped between the lower end of the shank and the countersunk head of the screw. A spring 244 cmbraces the pin shank and acts between an inner face of the top of the 232 and the inner face of the bottom of the element 236 to urge the element downwardly relative to the arm. Also, associated with each element 236, a guide pin 246 is secured to the inner surface ofthe top ofthe arm 232 and projectirig downwardly to be received in a sleeve 248 mounted in the element 236. Thus the elements 236 are yieldingly mounted, independently of one another, in the arms 232.

The arms 232 are arranged to support a separator member 250 having a separating edge 250a (FIGS. 15 and 16) shaped complementarily to the shape of the edge of the cut portion to be separated thereby and also to the shape of the separating edge 1080 of the plate 108 (forming part of the feed table) with which the member 250 cooperates.

In order to enable the member 250 to be supported on the arms 232, it is provided with four hooks 252 secured on the upper surface thereof, each hook comprising an upright portion and a securing portion extending forwardly from the upright portion. The securing portion is received within one of the hollow section elements 236, a portion of the end, remote from the press beam, of the bottom of each element being cut away to receive the upright portion of the hook. In mounting a separator member 250 on the arms, conveniently the operator places it slightly to the left (viewing FIG. 1) of the position in which it is desired to support it and urges it upwardly so that the hooks 252 press against the elements 236 adjacent those on to which it is desired to hook the member thus causing them to retract against the pressure of the springs 244. When the upper surface of the member 250 engages the elements the member is then moved to the right (see FIG. 1) to cause the lower surfaces of the securing portions of the hooks and the upper surface of the member to pass along opposite sides of the bottom of the elements whereby the member is secured thereto. When the member is moved sufficiently to the right the adjacent elements are caused to spring back into their lowermost position, thereby locking the hooks 252, and thus the member 250, in position.

In order that the plate 108 can be positioned accurately in relation not only to the position of the member 250 but also to the length of the feed stroke of the feed table, the position of the feed table fore and aft of the illustrative apparatus can be varied. For this purpose each end plate 124 constituting the carriage for the forward end of the feed table is provided with an outwardly projecting lug 254 on which a clamp 256 can be secured, the arrangement being such that with the clamps 256 in an inoperative condition the feed table can be moved lengthwise of the support bars 110 to a desired position, whereafter it is clamped in position.

In a cycle of operation of the illustrative apparatus a cut portion of sheet material deposited on to the plate 106 of the feed table is carried to a position above the stacking device when the feed table is moved to its advanced position. Thereafter the press bed and stacking table are raised as aforesaid to the limit of approach of the beam and bed, the feed table also being raised with the press bed to urge the cut portion supported thereon against the separator member 250 which, together with the elements 236, is caused to yield upwardly against the pressure of the springs 244. After the sheet material on the steel plate 104 has been cut the bed is lowered through a small distance such that when the feed table is moved to its retracted position the sheet material is restrained from movement therewith. As the plate 108 is drawn forwardly each element 236 returns under spring pressure to its initial position and the cut portion is progressively laid on the stack S. As the plate 108 is drawn past the separator member 250 the latter is held in its retracted position until the plate moves out of engagement therewith, the member 250 then being urged downwardly under the spring pressure and the edge thereof effecting a shear action with the edge of the plate 108 to insure that the cut portion is completely severed from the next portion of sheet material (see FIGS. 15 and 16).

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. I) mounted in a frame 262 inclined at an angle of 30 to the horizontal. Mounted along the frame, at each side thereof, are ten 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 by two 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 ofsheet material to be cut comprises ten 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 ten cut portions ofsheet 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 ten 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 L514 mounted on the side of one of the channels. This switch has a normally closed part LS14a and a normally open part LSl4b. 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 L514. The normally closed part LS14a 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 LS16 also mounted on the side of one of the channels 272, which switch breaks the circuit to the feed table, the latter being thus returned to its retracted position.

OPERATION: CUTTING (SINGLE STROKE) When it is desired to operate the illustrative apparatus on single stroke cutting, the operator sets a selector switch Sla, $112,510 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 L516, 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 RLl closes normally open contacts RLla, RLlb thereby bypassing respectively the limit switches LSl4b, L515, 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 movement 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. [8 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 RLl 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 90 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 TMRl 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 3 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, Sllc 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 PM. The operation of the operation ofthe 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 51c with a relay RL4 and also a lamp LP3 to indicate that automatic cutting is selected. Energization ofthe 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 RL4b (held closed by the relay RL4), a batch counter operated switch B510 normally held in its position shown in FIG. 18, and limit switches L516, LS14b and L515, 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 B510 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 rnakes a circuit to a lamp LP2 to indicate that the operation is ended.

OPERATION: DIE UN LOADING When it is desired to operate the illustrative apparatus to unload the die It from the press beam, the operator sets the selector switch Sla, Slb, 51C to a position designated 3 in FIG.

The operator again initiates an unloading cycle of operation in the same manner as for single cutting arid the cycle of operation continues in a generally similar manner to a single cutting operation until the press bed reaches its upper limit, opening the limit switch LS and thus causing the relay RL3 to be de-energized. When the contact RL3a now returns to its position shown in FIG. 18 a circuit is made, through the limit switch LS3, said contact RL3a, the limit switch LS4 (which has been moved from its position shown in FIG. 18) and the selector switch Slb. to a relay RL2 and also to a solenoid SOLS effective to cause the front and rear clamping bars 62 to move to the right and left (viewing FIG. 2) respectively, thus to release the die K on to the press bed. Movement of the piston rod 74 of the piston and cylinder arrangement C01 associated with the front clamping bar 62 is also effective to allow a normally closed part LS17a of a switch LS17 mounted on the press beam to close and a normally open part LS17b thereof to open and to allow a further switch L510 mounted adjacent the switch L517 on the press beam to move from its position shown in FIG. 18 whereby a circuit is made to the solenoid SOLZ to initiate the downward movement of the press bed. When the die moves away from the clamping bars 62, the switches LS6, LS7, LS8, LS9 move to their positions shown in FIG. 18.

Energization of the relay RL2 is also effective to cause a normally open contact RLZa to close and the contact RL2b to move from its position shown in FIG. 18. Thus when the press bed is moved downwardly, the tripping of the switch LS3 is rendered ineffective since a circuit is made through the contact RL2b, contact RL3a, switch LS4 (which has been moved from its position shown in FIG. 18), selector switch S112, and switches LS17a and L510 to the solenoid SOL2 whereby the press bed is moved continuously downwardly. Movement of the contact RL2b from its position shown in FIG. 18 breaks the circuit to the solenoid SOL3 but an alternative circuit is made through the contacts RL2b and RL3a, the switch LS4 and the contact RLZa. When the press bed reaches its lower limit and thus returns the switch LS4 to its position shown in FIG. 18 said alternative circuit is broken, whereby the feed table is then caused to return to its retracted position, and the relay RL2 is de-energized thus returning the contacts RLZa, RL2b to their positions shown in FIG. 18.

OPERATION: DIE LOADING When it is desired to load a die K on to the press beam, the operator sets the selector switch Sla, Slb, Slc to a position designated 4 in FIG. 18.

With the die K to be loaded supported on the feed table and located thereon by means of the blocks 94, the operator presses the start switch PM!) and. as with a single cutting operation, the feed table moves to its advanced position and thereafter the press bed is raised. As the die K is moved against the press beam the backing plate 44 thereof engages with the switches LS6, LS7, LS8, LS9 closing the normally open parts LS6a, L57a, LS8a, L590 whereby a circuit is made to a solenoid SOL6 effective to cause the front and rear clamping bars 62 to be moved to the left and right respectively to clamp the die on the press beam. At the same time normally closed parts LS6b, LS7b, LS8b, LS9b of the switches are opened thereby breaking the circuit to the solenoid SOLI, thus preventing further upward movement of the press bed and de-energizing the relay RL3; in this way any possible damage to the die is avoided. Also at the same time the switches L510, LS17a, and LSl7b are returned to their positions shown in FIG. 18 thereby making a circuit to the solenoid SOL2 which is effective to cause the press bed to move downwardly again.

The remainder of the cycle of operation is then effected in the same manner as for single cutting, the bed first being lowered sufficiently to ensure that the pins 98 of the blocks 94 are first withdrawn from the apertures 100 of the projections 84 on the die.

It will thus be noted that with the illustrative apparatus, dies can be loaded and unloaded using only the parts of the apparatus which are provided for the cutting operation thereof. Furthermore the stacking device of the apparatus operates without applying undue stress to the feed table which may consequently be made of a lighter material than would otherwise be the case.

As an alternative to loading a single die which covers the whole of the area of the base, the separate dies (not shown) may be mounted side by side on the beam without affecting in any way the operation of the press described above.

I claim:

1. Apparatus for cutting sheet material comprising in combination a press having a beam and a bed mounted for relative movement of approach and separation, die supporting means carried by said beam and operable selectively for clamping thereon a die presented thereto in a predetermined relative disposition and/or for unclamping a die supported thereby and a sensing means associated with said die supporting means and operative upon engagement of a die therewith to cause the clamping means of said die supporting means to be actuated to clamp the die on said beam.

2. Apparatus for cutting sheet material comprising in combination a press having a beam and a bed mounted for relative movement of approach and separation, die supporting means carried by said beam and operable selectively for clamping thereon a die presented thereto in a predetermined relative disposition and/or for unclamping a die supported thereby, a feed table movable between an advanced position in which a portion of the feed table is positioned between the beam and the bed of the press, and a retracted position in which a die to be detachably secured to the beam of the press can be placed on said portion of the feed table, said feed table having means thereon for locating a die thereon in a predetermined disposition when the feed table is in its retracted position, whereby when the feed table is caused to move to its advanced position to carry the die between the beam and the bed of the press, and a relative movement of approach is effected between the beam and the bed of the press to cause the die and the beam to be brought into engagement with one another, the die is in said predetermined relative disposition whereby the die supporting means is operative for clamping the die onto the beam.

3. Apparatus as in claim 2 and additionally comprising die sensing means carried by the die supporting means and operative in response to engagement of a die therewith to cause clamping means of the die supporting means to clamp the die onto the beam.

4. Apparatus as in claim 3 in which said die sensing means is additionally operative in response to engagement of a die therewith to terminate relative movement of approach of said beam and bed.