GB2078154A

GB2078154A - Rotary cutting tools

Info

Publication number: GB2078154A
Application number: GB8020293A
Authority: GB
Original assignee: Winkler and Duennebier Maschinefabrik und Eisengiesserei GmbH
Current assignee: Winkler and Duennebier Maschinefabrik und Eisengiesserei GmbH
Priority date: 1980-06-20
Filing date: 1980-06-20
Publication date: 1982-01-06
Also published as: GB2078154B

Abstract

A rotary cutting tool for production of cuts on envelopes, flat bags, or the like includes a rotary cutting element 2 which describes a cylindrical path, the cutting element cooperating with a stationary abutment which comprises a cylindrical ceramic rod 3 held adjustably in a holder 5 so that, by releasing adjustment means 4, 7 the abutment can be rotated about its axis and re-secured in position on the holder. <IMAGE>

Description

SPECIFICATION Rotary cutting tools This invention relates to a rotary cutting tool for production of cuts on moving webs or individual blanks of paper or the like, more particularly for preparation of envelopes, flat bags, or the like.

Specifically it relates to cutting tools whose cutting edges describe a cylindrical envelope, and at the instant of cutting impinge on a stationary abutment.

The invention comprises an improvement over the disclosure of German Patent Specification Number 121 5495 in which the operative area of a back-up member or abutment is in the form of a rounded edge produced by appropriate machining of one edge of a hard metal strip of square crosssection. A disadvantage of this construction is that only one edge of the hard metal strip can be used for cutting and if this edge experiences excessive wear, or is damaged, the entire strip, which is fairly expensive, has to be changed with fairly long machine down time. The object of the invention therefore, is so to construct and mount the abutment as to provide a maximum number of usable edges.

According to one aspect of the present invention a rotary cutting tool for the production of cuts on moving webs or individual blanks of paper or the like, e.g. for the production of envelopes or flat bags comprises a cutting element having an edge which describes a cylindrical path and which cooperates with a stationary abutment, the abutment having a circular cross-section and being mounted in a holder to allow for adjustment of the abutment by a rotation about its axis. The arrangement may be such, for example, that after a few bolts have been released the cylindrical abutment can be turned through a small angle and then re-locked in position.

The great advantage of an abutment according to the invention is that once a first zone of the abutment has become unusable due to wear or damage, a fresh undamaged area is available simply by turning the strip through a small angle.

This operation can be repeated at least some ten times, depending on the nature of the damage.

Another advantage is that abutments according to the invention greatly reduce the tendance for the effective area to crumble as in the case of the strips according to the German Patent Specification referred to above. It is therefore advantageously possible to make the strip from materials other than expensive hard metal. For example, the abutments may be made of ceramic material.

According to another aspect of the present invention a method of adjustment of a rotary cutting tool which includes a cutting element having an edge which describes a cylindrical path and which cooperates with a cylindrical stationary abutment includes releasing the stationary abutment from a holder to which it is secured, rotating the abutment about the axis of its cylindrical surface through a small angle and resecuring the abutment to the holder.

The invention may be carried into practice in a number of ways but one specific embodiment will now be described by way of example with reference to the accompanying drawing which shows a diagrammatic cross-section through a rotary cutting tool according to the present invention.

The drawings disclosed a rotary supporting cylinder 1 arranged to be driven in the direction of the arrow and carrying a closed window blade 2 which cooperates with a stationary abutment in the form of a cylindrical strip 3 made from ceramic and secured in a holder by means of a clamping bar or bars 4. The holder is adjustable in the direction of the double arrow for setting-up purposes. Once the system has been set at an optimum cutting action, i.e. a radial distance between the blade 2 and the abutment 3 equivalent to a fraction of the thickness of the material 6 to be cut, the holder 5 is fixed in its position.If excessive wear or damage to the operative area of the abutment 3 causes the cutting effect to deteriorate, after the rotary punch has operated for some time, then the bolts 7 used for clamping the bar 4 to the holder 5 can be released to enable the cylindrical abutment 3 to be turned through a small angle. The bolt 7 can then be re-tightened and the punch is ready for operation again.

1. A rotary cutting tool for the production of cuts on moving webs or individual blanks of paper or the like, e.g. the production of envelopes or flat bags, comprising a cutting element having an edge which describes a cylindrical path and which cooperates with a stationary abutment, the abutment having a circular cross section and being mounted in a holder to allow for adjustment of the abutment by a rotation about its axis.

2. A tool as claimed in Claim 1 in which the abutment is made from ceramic material.

3. A rotary cutting tool substantially as specifically described herein with reference to the accompanying drawing.

4. A method of adjustment of a rotary cutting tool for the production of cuts on moving webs or individual blanks of paper or the like which tool includes a cutting element having an edge which describes a cylindrical path and which cooperates with a cylindrical stationary abutment, the method comprising releasing the stationary abutment from a holder to which it is secured, rotating the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Rotary cutting tools This invention relates to a rotary cutting tool for production of cuts on moving webs or individual blanks of paper or the like, more particularly for preparation of envelopes, flat bags, or the like. Specifically it relates to cutting tools whose cutting edges describe a cylindrical envelope, and at the instant of cutting impinge on a stationary abutment. The invention comprises an improvement over the disclosure of German Patent Specification Number 121 5495 in which the operative area of a back-up member or abutment is in the form of a rounded edge produced by appropriate machining of one edge of a hard metal strip of square crosssection. A disadvantage of this construction is that only one edge of the hard metal strip can be used for cutting and if this edge experiences excessive wear, or is damaged, the entire strip, which is fairly expensive, has to be changed with fairly long machine down time. The object of the invention therefore, is so to construct and mount the abutment as to provide a maximum number of usable edges. According to one aspect of the present invention a rotary cutting tool for the production of cuts on moving webs or individual blanks of paper or the like, e.g. for the production of envelopes or flat bags comprises a cutting element having an edge which describes a cylindrical path and which cooperates with a stationary abutment, the abutment having a circular cross-section and being mounted in a holder to allow for adjustment of the abutment by a rotation about its axis. The arrangement may be such, for example, that after a few bolts have been released the cylindrical abutment can be turned through a small angle and then re-locked in position. The great advantage of an abutment according to the invention is that once a first zone of the abutment has become unusable due to wear or damage, a fresh undamaged area is available simply by turning the strip through a small angle. This operation can be repeated at least some ten times, depending on the nature of the damage. Another advantage is that abutments according to the invention greatly reduce the tendance for the effective area to crumble as in the case of the strips according to the German Patent Specification referred to above. It is therefore advantageously possible to make the strip from materials other than expensive hard metal. For example, the abutments may be made of ceramic material. According to another aspect of the present invention a method of adjustment of a rotary cutting tool which includes a cutting element having an edge which describes a cylindrical path and which cooperates with a cylindrical stationary abutment includes releasing the stationary abutment from a holder to which it is secured, rotating the abutment about the axis of its cylindrical surface through a small angle and resecuring the abutment to the holder. The invention may be carried into practice in a number of ways but one specific embodiment will now be described by way of example with reference to the accompanying drawing which shows a diagrammatic cross-section through a rotary cutting tool according to the present invention. The drawings disclosed a rotary supporting cylinder 1 arranged to be driven in the direction of the arrow and carrying a closed window blade 2 which cooperates with a stationary abutment in the form of a cylindrical strip 3 made from ceramic and secured in a holder by means of a clamping bar or bars 4. The holder is adjustable in the direction of the double arrow for setting-up purposes. Once the system has been set at an optimum cutting action, i.e. a radial distance between the blade 2 and the abutment 3 equivalent to a fraction of the thickness of the material 6 to be cut, the holder 5 is fixed in its position.If excessive wear or damage to the operative area of the abutment 3 causes the cutting effect to deteriorate, after the rotary punch has operated for some time, then the bolts 7 used for clamping the bar 4 to the holder 5 can be released to enable the cylindrical abutment 3 to be turned through a small angle. The bolt 7 can then be re-tightened and the punch is ready for operation again. CLAIMS

4. A method of adjustment of a rotary cutting tool for the production of cuts on moving webs or individual blanks of paper or the like which tool includes a cutting element having an edge which describes a cylindrical path and which cooperates with a cylindrical stationary abutment, the method comprising releasing the stationary abutment from a holder to which it is secured, rotating the abutment about the axis of its cylindrical surface through a small angle and resecuring the abutment to the holder.

5. A method of adjustment of a rotary cutting tool substantially as specifically described herein with reference to the accompanying drawing.