GB2055667A - Guillotines - Google Patents

Abstract

A power-operated guillotine for cutting paper and other materials has its knife (6) mounted on a frame (23) of greater strength and weight compared with the knife, which frame extends beyond the upper and lower ends of the knife and is guided for up and down movement in a fixed frame (10) which extends downwardly below the level of a die (7). The frame 23 is balanced by air springs. A clamp is provided in front of the knife and is loaded by an air spring. <IMAGE>

Description

SPECIFICATION Guillotines This invention relates to power-operated guillotines for cutting paper and other materials.

Such guillotines operate either with a scissor action in which the knife cuts progressively across the paper or with a vertical action in which the whole length of the knife makes simultaneous engagement with the material to be cut.

One disadvantage of scissor-action guillotines is that the movable carriage supporting the knife is usually disposed above the knife and slides in guides which terminate several inches short of the cutting edge. Consequently any thrust exerted on the knife by the material being cut in a direction at right angles to the cutting direction puts these guides under severe stress and makes it extremely difficult to maintain the cutting edge in the correct position relative to the face of the die, past which the knife must shear in order to make a clean cut through a plurality of sheets of material.

Consequently, it has been proposed to provide rubbing strakes which are movable with the knife and remain in permanent contact with the die, in order to prevent the knife from being forced out of position by even so much as one thousandth of an inch, which would be sufficient to cause the knife either to strike the die or to move away from the die and thus effect a ragged cut on the lowermost sheets of material in a stack.

It is a principal object, therefore, of the present invention to provide a guillotine in which the knife, whether operating with a vertical or scissor action, is always correctly positioned relatively to the die without the need for rubbing strakes and is capable of cutting any number of sheets up to the limit of the power available, without deformation of the moving parts.

To this end, according to the invention, the knife is mounted on a carriage having great strength and weight relative to the knife, which carriage extends beyond the upper and lower ends of the knife and is guided for up and down movement in a fixed frame which extends downwardly below the level of the die.

One embodiment of the invention will be described, by way of example, with reference to a machine comprising two guillotine units, each constructed in accordance with the invention, which are mounted on a frame supporting an endless conveyor and are adapted to cut two opposite edges of stacks of material fed thereto by the conveyor.

Such a machine is shown in the accompanying drawings in which: Figures 1 and 2 show the machine in partsectional side elevation and in horizontal sec tion respectively; Figure 3 is a vertical section at right angles to Fig. 1 showing the right-hand guillotine unit in front view; Figures 4 and 5 are vertical sections at right angles and Figure 6 is a horizontal section, through clamping mechanism for one of the dies; Figures 7 and 8 are vertical sections at right angles and Figure 9 is a horizontal section, through adjusting mechanism for one of the dies; and Figures 10 to 12 are detail sectional views showing the manner in which the knife of each guillotine unit is mounted on and se cured to a knife support.

Referring to the drawings, the two guillotine units are designated 1 and 2 and are shown as being mounted on a base frame 3 which supports endless conveyors 4 and 5 driven from a prime mover through suitable gearing and designed to feed paper or other material to and from a central cutting position beneath the knives 6 of both units to enable two opposite edges of the material to be cut simultaneously. Each knife 6 cooperates with a die 7 screwed to a bolster 8 which is shaped to permit conveyor belts or rollers to come as close to the edge of the die as possible and thus allow the passage of work of very small dimensions in the space be tween the two dies.Each bolster 8 is adjusta bly mounted on a cross-beam 9 forming the lower part of a frame 10 which also includes side plates 11 and 1 2 (Fig. 2), an upper cross-beam 1 3 and an end plate 14. Each frame 10 constitutes a rugged, robust, defiec tion-free box which, in the case of the guillo tine unit 1, is provided with slides 1 5 screwed to the side plates 11 and 1 2 and running in guides 1 6 on the frame 3 to enable the unit 1 to be moved towards and away from the unit 2 to accommodate different sizes of work to be cut.This movement is effected by rotation of a handle 1 7 which is operable through worm gearing 1 8 and a chain drive 1 9 to rotate a shaft 20 carrying pinions 21 which mesh with racks 22 on the frame 3.

A large robust tool frame 23 is slidably mounted in guideways formed in each frame 10 by metal rails 24 and 25 secured to the side and end plates 11, 1 2 and 14 and faced with anti-friction material 26. Each tool frame 23 is machined to conform exactly with the guideways and is secured at its lower end to cross-bridges 27 extending between and slida ble in slots in, two beams 28 which are reciprocable in a vertical direction by eccentric devices 29 driven by the prime mover which drives the conveyors 4, 5. Each frame 23 is supported by air springs in the form of cylin ders 30 which are mounted on the frame 3 and continuously exert an upward thrust on the beams 29 and thereby serve to counterbalance the weight of the frame 23.

Each knife 6 is mounted on its associated frame 23 through the medium of a knife support 31 to which it is secured by bolts 32 passing through elongated slots 33 in the knife support into tapped holes in the knife, and relative to which it is adjustable by means of screws 34 which extend out of bores 35 in the upper end of the knife into engagement with a flange 36 on the knife support. As the knife 6 wears, the screws 34 can be wound out of the knife to maintain the cutting edge of the knife at a constant distance from the lower face of the flange 36 and the bolts 32, when slackened, move down with the knife in the slots 33, before being tightened once again to clamp the knife to the support 31.

Each knife support 31 is formed, on its side remote from the knife 6, with T-slots 37 to receive the T-shaped heads 38 of threaded studs 39 which are passed through tapped holes in the frame 23 and secured thereto by nuts 40 which serve, when tightened, to draw the heads 38 towards the frame and clamp the knife support against it. The knives 6 can thus be fitted to their supports 31 outside the machine and the supports then slide transversely into position on the frames 23 over the heads 38 of the studs 39 without any need for further setting. A plate 41 is secured to the machined upper end of the tool frame 23 and supports two pairs of plates 42 and 43 in which is journalled a rotatable shaft 44 carrying clamp levers 45, 46 and 47.The levers 45 and 46 are connected to vertical rods 48 and 49 which are in turn secured to a clamp 50 in such a manner that when the shaft 44 is rotated, the clamp 50 moves up and down, in close relationship to the face of the knife 6, on vertical pillars 51 screwed to the plate 41.

The lever 47 is connected to the piston of an air cylinder 52 pivotally mounted in the plates 43 and in permanent communication at its upper end with an air reservoir (not shown), so that when the lower end of the clamp 50 engages the work 53 to be cut, the upward force exerted on the clamp by the work is transmitted through the levers 45, 46, the shaft 44 and the lever 47, to the air cylinder which acts as an air spring and the actual pressure applied to the clamp varies in direct proportion to the pressure applied to the air cylinder. Accordingly, as soon as the clamp 50 engages the work 53, it stops and the knife 6 carries on moving, relative thereto, into contact with the work, and eventually shears past the die 7 on the bolster 8.

Each die 7 on its bolster 8 is adjustable relative to the associated knife 6 at two points on the cross-beam 9 by die adjustment units 54 and is capable of being clamped in its adjusted position at three points on the crossbeam by die clamping units 55.

The die clamping units 55 are positioned at each end and at the mid-point of the crossbeam 9 and each unit includes a T-bolt 56 which is adapted to enter a T-shaped slot 57 in the underside of the bolster 8 when the latter is slid longitudinally along the top of the cross-beam. The threaded shank 58 of the bolt 56 is received in the tapped bore 59 of a spur gear 60 provided in an aperture in a shell plate 61 sandwiched between bearing plates 62 and 63 on the upper surface of the cross-beam 9. The spur gear 60 meshes with a spur gear 64 provided with a square or hexagonal head 65 which is accessible through an aperture 66 in the bearing plate 62 to enable it to be rotated by a square or hexagonal key. Rotation of the spur gear 64 acts through the spur gear 60 and bolt 56 to clamp the bolster 8 to the cross-beam 9.

The die adjustment units 54 are positioned inwardly of and adjacent to the die clamping units 55 at the ends of the cross-beam 9 and each includes a thrust block 67 which projects into the T-slot 57 in the bolster 8 and is tapped at 68 for the passage of a threaded stem 69 fixed to a worm wheel 70 on a shaft 71.

The worm wheel 70 meshes with a worm 72 having a square or hexagonal head 73 which is accessible through a hole in the bolster 8, and a shank 74 formed with a circumferential series of recesses 75 into which clicks a ball 76 biassed towards the worm by a spring 77. The recesses 75 are preferably so spaced that each angular movement of the worm 72 between clicks is operative, through the worm wheel 70, threaded stem 69 and thrust block 67 to move the bolster 8 by one thousandth of an inch with respect to the cross-beam 9.

To correctly position each die 7 with respect to the associated knife 6, the frame 23 is halted in its lowermost position with the cutting edge of the knife below the level of the die, feelers of plastics or other suitable material are inserted between the die and the knife and the bolster 8 is then eased toward the knife until the feelers are gently trapped between the die and the knife, If the thickness of each feeler is already known it is a simplematter to determine how many of the incremental movements of the worm 72 are required to bring the face of the die 7 into exact cutting position with respect to the knife 6.

Thus, with only one tool, in the form of a square or hexagonal key, it is possible, not only to carry out fine adjustment of each die 7, but also to lock the die in its adjusted position.

It can be seen that each frame 23 extends for some distance both above and below the level of the cutting edge of the associated knife 6 and accordingly, any thrust applied to the cutting edge in a direction at right angles to the direction of cut is evenly distributed over the whole of the frame without causing any deviation of the cutting edge from its predetermined path. Provided, therefore, that the associated die 7 is accurately set with respect to the face of the knife 6, the latter will cut satisfactorily over very long periods without having to be sharpened, due to the extreme rigidity of its relationship with the die.

The guillotine units may be operated in pairs as shown in the drawings, or singly, and in the latter case it is only necessary to provide one reciprocating beam 28.

In a modification for cutting one edge of work passing across the face of the machine, a single guillotine unit has a tool frame which, although extending below the level of the cutting edge of the knife, does not extend downwardly as far as the frame 23 shown in the drawings and, instead of being reciprocated by a beam at its lower end, has its upper end connected by links to one end of a rocker lever the other end of which is operatively connectedto an eccentric driving device by a vertically extending connecting rod. The whole machine is movable to enable material of different sizes to be cut, without having to alter the die and bolster relatively to the knife.

The invention has so far been described as applied to guillotines employing a vertical cutting action but there are some cases where a diagonal or "scissor" action could be an advantage. When, for instance, a pad having a paper strip applied to the back of it is required to be cut immediately after the application of the strip, a vertical action tends to compress the strip and cause it to separate from the back of the book with the consequence that slight tearing occurs as the knife passes through the paper. This can be reduced by pushing a metal block against the back edge but it is then necessary either to use metal blocks of different height with different thicknesses of work or to recess the clamp on the tool to miss the metal block.By employing a scissor action towards the back edge of the book, the strip on which the glue is not yet dry will be pushed towards the back face of the book which then acts as a shear die to ensure that the strip is cut cleanly.

With this in mind, the tool frame may be mounted with its sides extending at an inclination to the vertical while the knife still extends horizontally and parallel to the work. When the frame is reciprocated in a direction parallel to its sides the knife is given a horizontal component to its motion. Since the clamp must not have a horizontal component to its motion it can either be mounted separately or provided, at its lower end, with a section slidably horizontally relative to the main body of the clamp. In operation, when the lower section engages the work it remains stationary thereon to clamp it while the main body of the clamp continues to move with a horizontal component and is thus displaced horizontally with respect to the lower section.

Claims (22)

1. A power-operated guillotine, comprising a die, carried by a stationary frame of great strength which extends downwardly below the level of the die and a knife mounted for cutting movement past said die on a movable frame of great strength and weight which extends above and below the levels of the upper and lower ends of the knife and is slidably mounted for generally vertical movement in said stationary frame.

2. A power-operated guillotine, comprising a stationary frame, a clamp movable relative to said frame into engagement with work to be cut, a knife movable with and relative to said clamp for cutting the work engaged by the clamp, and a die mounted on said frame for cooperation with said knife, said knife being carried by a reciprocable frame which extends above and below the knife and is slidably mounted in said stationary frame, said movable frame being of a strength and weight sufficient to prevent any deflection of said knife away from its predetermined path of cutting movement past said die.

3. A guillotine according to Claim 1 or 2, wherein adjustment and clamping means are provided for correctly positioning said die on said stationary frame in relation to the path of cutting movement of the knife.

4. A guillotine according to Claim 3, wherein said die is mounted on a bolster provided on its underside with a shouldered slot upon the sides and shoulders of which the adjustment and clamping means operate respectively.

5. A guillotine according to Claim 4, wherein said adjustment means comprises a thrust block movable along the threaded stem of a worm wheel in response to manual rotation of a worm meshing with said wheel.

6. A guillotine according to Claim 4 or 5, wherein said clamping means comprises a bolt the head of which engages said shoulders and the shank of which is movable axially in the threaded bore of a spur gear in response to manual rotation of another spur gear meshing with said first spur gear.

7. A guillotine according to Claims 5 and 6, wherein said worm and said other spur gear are rotatable by the same tool.

8. A guillotine according to any preceding claim, wherein said knife is detachably secured in a holder which is detachably secured to said movable frame.

9. A guillotine according to Claim 8, wherein said knife is adjustable in said holder in the direction of cutting to maintain a constant distance between the cutting edge and a fixed point on said holder.

10. A guillotine according to Claim 9, wherein adjustment of the knife is effected by the rotation of screws, the lower ends of which enter the upper end of the knife and the heads of which engage a flange at the upper end of the holder.

11. A guillotine according to any one of Claims 8 to 10, wherein the side of the holder remote from the knife is formed with T-slots which engage over the heads of bolts passing through the movable frame and tightened by nuts on their outer ends.

1 2. A guillotine according to any preceding claim, wherein said movable frame is secured at its lower end to a beam which is reciprocable in a vertical direction by an eccentric device driven by a prime mover.

13. A guillotine according to Claim 12, wherein downward movement of said beam is resisted by a piston and cylinder device connected to an air reservoir.

14. A guillotine according to any preceding claim, wherein said clamp is mounted on said movable frame for limited movement with said frame into and out of engagement with the work to be cut and for movement relative to said frame against the action of a piston and cylinder device connected to an air reservoir while in clamping engagement with the work.

1 5. A guillotine according to Claim 14, wherein said clamp is slidable on pillars secured to said movable frame and is connected to said piston and cylinder device by a horizontal shaft rotatable in said frame and connected both to said clamp and to the piston of said device.

1 6. A guillotine according to any one of Claims 1 to 11, wherein the upper end of said movable frame is connected by links to one end of a rocker lever the other end of which is operatively connected, by a vertically extending connecting rod, to an eccentric device driven by a prime mover.

17. A guillotine according to any one of Claims 1 to 15, wherein the sides of said movable frame extend at an inclination to the vertical and said frame is mounted in the stationary frame for movement in a direction parallel to its sides, whilst the knife extends in a horizontal direction parallel to the work.

1 8. A guillotine according to Claim 17, wherein said clamp comprises a lower part which moves vertically into engagement with the work and an upper part which is movable horizontally with respect to the lower part when the latter is in engagement with the work.

1 9. A machine for cutting paper and other materials comprising two guillotines according to any one of Claims 1 to 1 5 mounted in spaced relationship on a base frame supporting endless conveying means for feeding work to be cut at two opposite edges to the space between the guillotines.

20. A machine according to Claim 19, wherein one of said guillotines is adjustable on said base frame towards and away from the other guillotine.

21. A machine according to Claim 20, wherein the stationary frame of said adjustable guillotine is slidable in guides in said base frame in response to the operation of a rack and pinion mechanism.

22. A guillotine substantially as hereinbefore described with reference to and as shown in the accompanying drawings.