GB2332165A

GB2332165A - Blade securing apparatus for a cutting roller

Info

Publication number: GB2332165A
Application number: GB9726286A
Authority: GB
Inventors: Timothy Leonard Kew
Original assignee: T & S Engineering Co
Current assignee: T & S Engineering Co
Priority date: 1997-12-13
Filing date: 1997-12-13
Publication date: 1999-06-16
Anticipated expiration: 2017-12-13
Also published as: GB2332165A9; GB9726286D0; GB2332165B

Abstract

A cutting roller 7 has a blade 2 lying parallel to its axis and cooperates with a backing roller 8 to make transverse cuts in a web 6 passing between them. The blade is secured against one side (15 fig 2) of an axial slot 14 on the cutting roller by means of a clamp bar 3. The clamp bar is forced against the blade by a resilient member 4 which itself reacts against a back plate 5 which rests against the other side (16 fig 2) of the slot. Radial movement of the clamp bar is prevented by means of bolts (23 fig 6) at either ends of the bar which are secured to the bottom surface of the slot. Adjusting screws 9 are threaded through the clamp bar and engage the bottom of the slot to provide a means for adjusting the height of the blade. A tool (18 fig 5) is used to engage the clamp bar and rotate it sufficiently in order to insert or extract the blade.

Description

2332165 1 DEVICE AND METHOD FOR SECURING BLADES This invention relates to

a device for securing blades in a rotatable cylinder. This invention also relates to a method for inserting the device and blade into such a cylinder.

More specifically, this invention relates to the securing of cutting or perforating knife blades in a rotatable cylinder, employed for cutting or perforating a running web passing through the nip between a rotatable cylinder provided with such blades and a corresponding anvil cylinder. The running web, may, for instance, be made from paper, card, or film, such as plastics sheet or film.

Such cutting and perforating knives are generally located in a slot in the rotatable cylinder, the knife blade being held in place by means of retaining device fitting within a slot in the surface of the cylinder, and extending in a direction parallel to the axis of the cylinder. In general, the devices in common use are complicated, so that replacing blunted blades, or inserting blades for a different form of cut, is a laborious process.

One commonly used device clamps a knife blade against a datum face of a slot by means of a clamp bar running longitudinally of the slot. The clamp bar is urged against the knife blade and datum face by means of a series of bolts rotatable in threaded bores which, when the clamp bar is in position within the slot, are perpendicular to the datum face and rear face of the slot. The heads of the bolts bear against the rear face of the slot, and the locking bar and knife blade are urged against the datum face by tightening lock nuts on the threaded bolt until they bear upon the rear face of the clamp bar. With such a system, it is a laborious process adjusting the individual bolts and lock nuts in order to 2 adjust the clamping force consistently along the length of the clamp bar when a knife blade is being inserted or replaced.

The purpose of the present invention is to solve the problem of providing a simple and inexpensive device for inserting and holding knife blades within a slot of conventional dimensions.

One embodiment of the present invention provides a device for securing a knife blade within a slot extending across the surface of a rotatable cylinder in a direction parallel to the axis of said cylinder, said slot having a datum face lying on a radius of the cylinder, a back face substantially parallel to the datum face, and a bottom face, which device comprises a clamp bar of substantially rectangular cross section having a first face and an opposing second face, with a step at the bottom or in a lower portion of the first face and a longitudinal groove extending across the second face, and the back plate having a first face provided with a longitudinal groove and a second face, with an extended resilient member adapted to fit partially within the respective grooves on the clamp bar and back plate, said clamp bar being provided with height adjustment screws parallel to the first and second faces.

The present invention also provides a method of inserting a device as described above within a slot extending across the surface of a rotatable cylinder in a direction parallel to the axis of said cylinder, said slot having a datum face lying on a radius of the cylinder, a back face substantially parallel to the datum face, and a bottom face, which method comprises applying force whereby the clamp bar and back plate pivot about the resilient member to urge the lower ends of the clamp bar and back plate towards one another to provide a wedge-shaped profile, inserting said wedge shape into the slot, and in providing force axial of the cylinder to push the device into the slot, inserting a knife blade between the first face of the clamp bar and the datum face of the slot, rotating the cylinder until the knife blade contacts an anvil 3 cylinder, thereby displacing the knife blade such that it is set at the correct height for perforating a running web, passing through the nip between the rotatable cylinder and the anvil cylinder' and turning the adjust screws until they contact the bottom face of the slot.

The present invention will be further described with reference to the accompanying Drawings, in which:

Fig. 1 is a view of the rotatable cylinder, an anvil cylinder and a running web; Fig. 2 is a partially cut-away view of a device within a slot, showing the various components of the device in section; Fig. 3 is a partial sectional view of the periphery of a cylinder showing the device and a blade located in a slot.

Fig. 4 is a partial sectional view of the periphery of a cylinder showing the initial stages of insertion of the device within the slot.

Fig. 5 is an elevation of a tool employable for use in inserting a device according to the invention into a slot or in removing it.

Fig. 5A illustrates the use of the tool.

Fig. 6 is a partial sectional view of a clamp bar in a slot.

Referring now to the Drawings, a web [6] runs through the nip between a rotatable cylinder [71 and an anvil cylinder [81. The rotatable cylinder [71 is provided with a pair of slots [141 so located that each contains a blade [21, the blades being diametrically opposed at the periphery of the cylinder. If desired, 4 the number of slots could be varied, the only requirement being that the blades are so located as to produce cuts or perforations at desired intervals in the running web.

Each slot has a datum face [151, against which a knife blade is urged, a back face [16] and a bottom face [171. The datum face and the back face will generally be substantially perpendicular to the bottom face 1141, and the datum face [151 will lie on a radius of the cylinder. The slots and the cylinders are generally of conventional construction. The dimensions of the slots and the materials from which the cylinders are formed will be well known to those skilled in the art.

The device itself comprises a clamp bar [31 for urging a blade [21 against the datum face [151, in a manner to be described more fully below. The back plate [51 is urged against the back f ace of the slots [ 161, and the clamp bar [31 and the back plate [51 are each provided with a respective longitudinal groove [12,12'] which, when the device is in position in the slot, will be parallel tothe axis of the cylinder. An extended longitudinal member [41, formed from natural or synthetic rubber, or other resilient material, is adapted to fit partially within the respective grooves and is of such dimensions as to provide a space between the clamp bar and the back plate and to urge each of them in opposed directions so as to bear against the respective faces of the groove. The longitudinal member [141 is conveniently circular in cross- section, but other profiles may be used, if desired. The clamp bar [31 is provided with threaded bores for one or more height adjusting screws [91, and one or more locking screws [101, and a plurality of bores [111 for use in inserting the device, and replacing knife blades, in a manner described below. The clamp bar [31 is provided with a step [131 at the bottom of the face not having the groove [121, so as to support a blade [21 being urged against the datum face of the slot by means of the resilience of the longitudinal member [41 acting upon the clamp bar and the back plate, pushing them away from one another.

The device may be inserted into, or removed from a slot, or a blade may be changed without removing the device from a slot making use of a tool [183 as shown in Fig. 5 of the Drawings. The tool [181 has a handle [191 connected to a cross piece [201 by means of bolts [221 or in any other convenient manner. The cross piece [201 has a series of projections [211 parallel to the handle [201 and adapted to engage in corresponding bores [111 in the clamp bar [31.

The manner in which the device may be inserted into a slot [141 is shown in Figs. 4 and SA of the Drawings. Inward pressure may be applied to the base of the device by urging the handle [191 in the opposite direction to the arrow as shown in Fig. SA, so that the clamp bar [31 and the back plate [51 pivot about the elongated longitudinal member [41, temporarily providing a wedge shape for the device which allows it to be inserted into the slot. On the application of firm pressure towards the axis of the cylinder, the device will be urged into the slot, and the elongated longitudinal member [41 will be deformed, as a consequence of its resilience. As a result, when the device is fully inserted, the resilience of the member [41 will urge the back plate [51 against the back face [161 of the slot, and urge the clamp bar [31 against the datum face [151 of the slot [141. A knife blade [21 can then be inserted, by means of the tool [181, which is urged in the direction shown by the arrow in Fig - SA so as partially to compress the longitudinal member [41 and permit the clamp bar 131 to rotate about a centre where the step bears on the datum face of the slot. The knife blade 121 can then be slipped into the space between the clamp bar and the face. The tool [181 can then be removed. Abladecan be replaced, without removing the device from the slot, by applying force to the handle of the tool, in the direction of the arrow shown in Fig. SA, removing one blade, and replacing it with another. The rotatable cylinder [71 is then rotated relative to the anvil cylinder [81. This has the consequence that the knife blade [21 is displaced axially of the rotatable cylinder [7) until it provides the correct height for perforation of a running web. Height 6 adjustment screws [91 are then screwed down so that they contact the bottom face [171 of the slot [141, and the height adjustment screws [91 are then secured by the locking screws [10]. Displacement of the device radially outwards of the centre can be prevented by means of the stop member [231 fitting in a bore of the cylinder.

7

Claims

1. A device [11 for securing a knife blade [21 within a slot [141 extending across the surface of a rotatable cylinder [71 in a direction parallel to the axis of said cylinder, said slot [141 having a datum face [151 lying on a radius of the cylinder, a back face [161 substantially parallel to the datum face, and a bottom face [171, which device comprises a clamp bar [31 of substantially rectangular cross section having a first face and an opposing second face, with a step [131 at the bottom or in a lower portion of the first face and a longitudinal groove [ 121 extending across the second face, and the back plate [51 having a first face provided with a longitudinal groove [12'] and a second face, with an extended resilient member [4] adapted to fit partially within the respective grooves [12,12'] on the clamp bar and back plate, said clamp bar being provided with height adjustment screws [91 parallel to the first and second faces.

2. A device according to Claim 1 wherein the clamp bar [31 is provided with locking screws [101 for securing the height adjustment screws [91.

3. A device according to Claim 1 or 2 wherein the clamp bar is provided with a plurality of bores [111 for engaging corresponding projections [211 in an insertion tool [181.

4. A device according to any one of Claims 1 to 3 wherein the resilient member [41 has a circular cross section.

5. A device according to Claim 1 and substantially as hereinbefore described.

6. A method of securing a device according to any one of Claims 1 to 5 within a slot [141 extending across the surface of a rotatable cylinder [71 in a 8 direction parallel to the axis of said cylinder, said slot [ 141 having a datum face [ 151 lying on a radius of the cylinder, a back face [16] substantially parallel to the datum face, and a bottom face [171, which method comprises applying force whereby the clamp bar and back plate pivot about the resilient member [41 to urge the lower ends of the clamp bar and back plate towards one another and to provide a wedge-shaped profile, inserting said wedge shape into the slot [141, and in providing force axial of the cylinder to push the device into the slot, inserting a knife blade [21 between the first face of the clamp bar [31 and the datum face [151 of the slot, rotating the cylinder until the knife blade contacts an anvil cylinder [8], thereby displacing the knife blade such that it is set at the correct height for perforating a running web [61, passing through the nip between the rotatable cylinder [7] and the anvil cylinder [81, and turning the height adjustment screws [9] until they contact the bottom face [17) of the slot.

7. A method according to Claim 6 wherein the knife blade [21 is inserted by means of a tool [ 181 having a handle [ 191 and a cross piece [201 provided with a plurality of projections [211 adapted to engage corresponding bores [ 111 in the clamp bar [31, wherein said projections are inserted into said bore, pressure is applied to said handle 1191 wherein to urge the upper portion of said clamp bar [3) towards the upper portion of said back plate [51, about a pivot by said step [131 bearing on the datum face [151 of said slot, inserting the knife blade [21, and allowing the resilient member [4) to urge the clamp bar to sandwich the knife blade [21 between the first face of the clamp bar and the datum face of the slot.

8. A method as claimed in Claim 6 and substantially as hereinbefore described.