GB2064406A

GB2064406A - Apparatus for Cutting Out Discs From a Workpiece

Info

Publication number: GB2064406A
Application number: GB8020766A
Authority: GB
Original assignee: TEMPO SANYS
Current assignee: TEMPO SANYS
Priority date: 1979-12-06
Filing date: 1980-06-25
Publication date: 1981-06-17
Also published as: CA1138326A; DE3023394A1; BE883871A; CH636799A5; AT373298B; MX150478A; FR2470663A1; GB2064406B; ATA317680A; ES493077A0; NL185990B; IT1131337B; IT8022840A0; JPS6330430B2; ES8702819A1; NL8003513A; NL185990C; JPS56154572A; FR2470663B1; GR69204B

Abstract

Apparatus for cutting out discs from a sheet or web (A) of flexible material, for example cotton, which is displaced with a stepping movement at a given frequency, comprises a punch assembly (1) comprising a plurality of punch members (2) co- operable with a die (3) provided with apertures (4) corresponding to the punch members (2). The apparatus comprises means for compensating for displacement of the axis of one or more of the punch members (2) with respect to the die (3). Such means may comprise spherical cutting surfaces (7) and/or resilient joint members (13) and/or (15). <IMAGE>

Description

SPECIFICATION Apparatus for Cutting Out Discs from a Workpiece The present invention relates to apparatus for cutting out discs from a workpiece, which may for instance be a,web or sheet, possibly of a flexible material, for example of cotton fibre.

Cutting presses which comprise a punch cooperable with a die are well known in the art, and it is possible to produce tools of this kind which are capable of operating with a very high degree of accuracy.

However, such equipment is of extremely high cost, out of proportion with a certain number of industrial operations such as cutting out cotton discs, which are used for removing makeup, from a cotton sheet or cloth.

Indeed, when cotton discs of this kind, for removing makeup, are to be cut out, for example using the apparatus described in French Patent No. 79 25 358, for reasons of speed, and therefore economy, it is usual to employ a press which comprises a punch having a plurality of twinned or paired punch members (i.e. punch members secured to one and the same punch) cooperable with a die provided with apertures corresponding to the punch members.

However, unless a press of this kind is built of high performance material, and unless it is built to very accurate dimensions, the press can result in the results obtained being unsatisfactory. Indeed, it may happen that the axis of the assembly or a part of the punch becomes offset with respect to the axis of the die, particularly due to non-uniform expansion of the punch, which results in alterations in the respective distances or dimensions of the different punch members, or different expansion of the punch and the die.

Now, such phenomena are harmful to the production rate or the quality of the product obtained, insofar as, when using punch members of conventional type, whose cutting surfaces are cylindrical or tapered, the axis of the cutting surface is no longer exactly opposite the corresponding punch members of the punch assembly and therefore the cutting surfaces become oval and non-circular; this means that one or more punch members of the punch assembly produce incomplete cutting which is therefore unsatisfactory.

Hitherto, in order to obtain a good cutting action, the above-indicated disadvantage required the use of presses whose quality was markedly higher than the work which was required therefrom.

According to the present invention there is provided apparatus for cutting out discs from a workpiece, the apparatus comprising a punch assembly with respect to which, in use, the workpiece is displaced with a stepping movement at a given frequency, the punch assembly comprising a plurality of paired punch members co-operable with a die provided with apertures corresponding to the punch members, and compensating means for compensating for any displacement of the axis of one or more of the punch members with respect to the die.

The compensating means of a preferred embodiment of the invention described hereinbelow makes it possible, for cutting out cotton discs, to use apparatus which is markedly less precise or sophisticated than the presses which had to be used hitherto, and therefore greatly reduces the cost of cutting out the discs.

In accordance with a preferred feature of the invention, the compensating means comprises a spherical cutitng surface provided on each of the punch members.

Indeed, if each punch member is provided with a spherical cutting surface, replacing the cylindrical or tapered cutting surfaces which are conventionally employed, when the axis of the punch member is displaced with respect to the axis of the die the punch member still presents a surface of circular section and not oval section, opposite the aperture in the die corresponding thereto, and consequently, by virtue of flexibility of means for guiding the punch member, it will still be possible to obtain satisfactory cutting over the whole of the periphery of the disc.

In accordance with another preferred feature of the invention, the compensating means comprises members which make it possible to give each punch member a certain degree of autonomy or independence with respect to the punch assembly.

This arrangement makes it possible to provide, as it were, an individual guide action in respect of each punch member, which accordingly automatically takes up a position precisely facing the aperture in the die corresponding to that punch member.

In accordance with another preferred feature of the invention, each punch member is disposed in a housing in the punch assembly and the members which permit a certain degree of independence for each punch member are resilient joint or packing members disposed in the housings.

The joint members may be flat joint members of a flexible plastics material disposed in a shoulder provided in the upper part of each housing, which permits each punch member to enjoy independence in the axial direction. The joint members may instead or also be toric joint members of a flexible plastics material disposed in grooves provided on the peripheries of the punch members, thus providing each punch member with radial independence with respect to the punch assembly.

It will be appreciated that it is particularly attractive for a flat joint member and one or more toric joint members to be combined for each punch member, thus making it possible to overcome any offset which may occur in any direction whatsoever in any of the three dimensions.

In accordance with another preferred feature of the invention, each punch member comprises therewithin a piston capable of pushing a cut-out disc into the corresponding aperture in the die.

Moreover, in the same vein, it would be possible to provide for the die to have means permitting it to be mounted or guided in a flexibility mode, without thereby departing from the scope of the invention.

A cutting apparatus embodying the present invention will now be described in detail by way of illustrative and non-limiting example, with reference to the accompanying drawing, which is a diagrammatic sectional view of such apparatus, wherein only a single punch member is illustrated, for the sake of clarity.

Referring to the drawing, the apparatus embodying the invention is intended to cut discs B from a sheet or web A of a flexible material such as for example cotton which is displaced with a stepping movement as diagrammatically illustrated by an arrow X.

In conventional manner, the apparatus comprises a punch assembly 1 comprising a plurality of paired punch members 2, only one of which is shown in the drawing, which co-operates with a die 3 provided with apertures 4 corresponding to the punch members 2. The statement that the punch members 2 are 'paired' means that the members 2 are mounted on one and the same punch assembly 1.

Each punch member 2 comprises therein a piston 6 which is capable of moving downwardly, as indicated by an arrow Z, under the control of a mechanism which is not shown in the drawing.

The punch assembly 1 is connected to a control mechanism (not shown) capable of driving it with a vertical reciprocating movement, as indicated by an arrow Y, being guided by a slide 5.

Thus, in the lower position (shown in the drawing), the lower surface or cutting surface 7 of the punch member 2 strikes against the outside edge of the aperture 4 in the die 3, which causes the disc B to be cut out. At that moment, the piston 6 pushes the disc B into the aperture 4 in which it is collected in a device (not shown).

In order to produce satisfactory cutting of the discs B, the axis h-h' of each punch member 2 must coincide precisely with the axis of the corresponding aperture 4 in the die 3, which is not always the case by virtue of the different expansion phenomena to which the different parts of the punch assembly 1 and the die 3 are subjected.

In order to compensate for the possible effects of such differences in expansion. the cutting surfaces 7 of the punch members 2 are of spherical shape so that, even when there is a slight degree of displacement as between the axis h-h' of a punch member 2 and the corresponding aperture 4 in the die 3, the punch member 2 presents a circular section with respect to the aperture 4 corresponding thereto, thus permitting a satisfactory cut to be produced around the whole periphery of the disc B.

In the drawing, the cutting surfaces 7 have been extended by broken lines, in order clearly to show their spherical shape.

Moreover, the punch assembly 1 comprises two parts 8 and 9 which are assembled by screws 10 (shown in diagrammatic form in broken lines in the drawing). Provided between the different parts 8 and 9 are housings 11 for the punch members 2. The upper part 12 of each housing 11 has a shoulder for receiving a flat flexible joint or packing member 13 which permits the punch members to enjoy a certain degree of freedom in the vertical direction.

The periphery 14 of each punch member 2 is provided with grooves for receiving toric joint or packing members 1 5 which also allow the punch member 2 to have a certain degree of independence in its housing 14. It will be appreciated that this arrangement is the same in regard to all the punch members of the same punch assembly, thus permitting all the punch members to have a certain degree of independence relative to each other, this independence making it possible automatically to compensate for possible angular or radial displacement of the axis h-h' of a punch member 2 relative to the axis of the aperture 4 in the die 3, which corresponds to that punch member.

It will be appreciated that the punch assembly 1 may comprise any number of punch members without thereby departing from the scope of the invention.

Claims

1. Apparatus for cutting out discs from a workpiece, the apparatus comprising a punch assembly with respect to which, in use, the workpiece is displaced with a stepping movement at a given frequency, the punch assembly comprising a plurality of paired punch members co-operable with a die provided with apertures corresponding to the punch members, and compensating means for compensating for any displacement of the axis of one or more of the punch members with respect to the die.

2. Apparatus according to claim 1, wherein the compensating means comprises a spherical cutting surface provided on each of the punch members.

3. Apparatus according to claim 1 or claim 2, wherein the compensating means is operative to compensate for angular or radial displacement of the axis of one or more of the punch members with respect to the die and comprises members which permit each punch member to have a certain degree of autonomy with respect to the punch assembly.

4. Apparatus according to claim 3, wherein each punch member is disposed in a housing provided in the punch assembly and said members allow each punch member a certain degree of autonomy in the axial direction and comprise resilient joint members disposed in said housings.

5. Apparatus according to claim 4, wherein the resilient joint members comprise flat joint members of a flexible plastics material disposed in shoulders in an upper part of each housing.

6. Apparatus according to claim 4 or claim 5, wherein the resilient joint members comprise toric joint members of flexible plastics material disposed in grooves in the peripheries of the punch members.

7. Apparatus according to any one of claims 1 to 6, wherein each punch member comprises therewithin a piston capable of pushing a cut-out disc into the corresponding aperture in the die.

8. A roll mill or calender operatively associated with an extruder head, substantially as herein before described, with reference to the accompanying drawings.

8. Apparatus for cutting out discs from a workpiece, the apparatus being substantially as herein described with reference to the accompanying drawing.

9. A disc cut out by apparatus according to any one of the preceding claims.

Claims

1. A roll mill or calender operatively associated with an extruder head, the rollers of which are coupled for rotary propulsion to a drive motor through a transmission and which can be moved selectively by means of a drive means out of a work position into a cleaning position and optionally into an extruder worm demounting position at a distance from the extruder head, wherein the roll mill or calender is mounted for pivotal movement about a pivot bearing which is arranged at a predetermined lateral distance from the longitudinal axis of the extruder.

2. A roll mill or calender according to Claim 1, wherein the pivot bearing is arranged beneath the drive means which forms a unit comprising the drive motor and the transmission.

3. A roll mill or calender according to Claim 1 or Claim 2, wherein the pivot bearing is arranged on the side nearer the extruder of a vertical plane passing through the axes of the rollers and at a distance from this plane.

4. A roll mill or calender according to any one of Claims 1 to 3, wherein the calender includes a support means which is supported at mutually spaced bearing positions on sliding tracks which are constructed in the manner of hydrostatic sliding guides.

5. A roll mill or calender according to any one of Claims 1 to 4, wherein the drive motor and the transmission are supported on a sliding track which is constructed in the manner of a hydrostatic sliding guide.

6. A roll mill according to any one of Claims 1 to 5, wherein the pivot bearing is mounted with freedom of movement in the direction of the longitudinal axis of the extruder.

7. A roll mill or calender according to any one of Claims 1 to 6, and having a hydraulically operable piston/cylinder drive means serving as the swivelling drive, which drive is articulated at one end to the roll mill or calender and is connected at its other end relatively fixed point, wherein the swivelling drive can be articulated by one end selectively to one of two articulation points.