WO2001032370A1

WO2001032370A1 - Retractable needle unit for a punching apparatus

Info

Publication number: WO2001032370A1
Application number: PCT/CA2000/001296
Authority: WO
Inventors: Benoît LECLERC
Original assignee: Bonar Inc.
Priority date: 1999-11-03
Filing date: 2000-11-03
Publication date: 2001-05-10
Also published as: AU1260701A; CA2288259A1

Abstract

A retractable needle unit (10) for use on the roller (12) of a punching apparatus is provided. The unit (10) has a support wheel (16) coaxially mountable on the shaft (14) of the roller (12). A plurality of needles (26) are mounted on the support wheel (16), each of which being pivotable in the radial plane of the support wheel (16) between an operative position where it partially projects beyond the outer circumference of the support wheel (16) and a retracted position where it lies within the outer circumference. The unit (10) also includes a guiding wheel (34) rotatably mountable on the shaft (14) besides the support wheel (16), and being provided with a plurality of needle guides to engage the punching needles (26). Therefore, rotating the guiding wheel (34) pivots the needles (26) between the retracted and operative positions. The guiding wheel (34) is lockable with respect to the support wheel (16).

Description

RETRACTABLE NEEDLE UNIT FOR A PUNCHING APPARATUS

FIELD OF THE INVENTION

The present invention relates to the field of paper or plastic perforation, and more particularly concerns a retractable needle unit for use on the roller shaft of a punching apparatus.

BACKGROUND

It is well known in the art of packaging or paper transformation in general to use perforation to increase the porosity of paper or plastic. For this purpose, punching apparatuses are provided using male and female type rollers as shown for example in FIG. 1 (prior art). The male roller is usually a shaft provided with a multitude of threaded holes therein, and a small punching needle is threaded individually in each hole. The holes are distributed evenly to provide a uniform and regular distribution of the perforations along the length and width of paper or plastic.

The above described system has several drawbacks. It is very difficult to change the pattern of the perforations. For example, to eliminate a row of perforations in the circulating direction of the paper, all the needles along a given cross-section of the roller have to be removed one by one. In addition to being tedious, this operation may provoke the degradation of the threads of the holes, eventually rendering certain holes unusable. The needles themselves are often fragile and may be easily damaged by the manipulation. As a consequence, the aesthetical aspect of the finished product is undermined. There is therefore a need for a device which would allow modification of the perforation pattern without the need to remove the punching needles of a given row by hand.

OBJECT AND SUMMARY OF THE INVENTION It is an object of the present invention to provide a roller shaft of a punching apparatus with easily retractable needles. Accordingly, the present invention provides a retractable needle unit for a punching apparatus having a punching roller provided with a shaft. The unit has a support wheel rigidly mountable around the shaft and having an annular face extending within a radial plane. The unit also includes a plurality of punching needles mountable in a circular pattern on the annular face of the support wheel. Each of these punching needles is pivotable in the radial plane between an operative position, where it partially projects beyond an outer circumference of the support wheel, and a retracted position, where it lies within said outer circumference. A guiding wheel rotatably mountable around the shaft proximate to the support wheel is also provided. The guiding wheel has a face provided with a plurality of needle guides therein, for engaging each of the punching needles. Therefore, a rotation of the guiding wheel with respect to the support wheel pivots the punching needle between the operative position and the retracted position. Finally, locking means for locking the guiding wheel with respect to the support wheel are provided.

Preferably, in another aspect of the invention, a punching roller for a punching apparatus is provided, having a shaft and a plurality of retractable needle units as described above. The retractable needle units are coaxially and rigidly mounted on the shaft. The punching roller also includes a plurality of resilient tightening members, each of said resilient tightening members being mounted on the shaft between two adjacent retractable needle units, in contact with both of these adjacent needle units.

The present invention and its advantages will be better understood upon reading the following non-restrictive description of embodiments thereof with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a pair of male and female rollers in a punching apparatus according to the prior art. FIG. 2 is a side view of a pair of male and female rollers in a punching apparatus in accordance with a preferred embodiment of the invention.

FIG. 3 is a top and side perspective view of a component of a retractable needle unit according to the preferred embodiment of the invention. FIG. 4 is a bottom and side perspective view of another component of the retractable needle unit, which cooperates with the component shown in figure 3, according to a preferred embodiment of the invention.

FIG. 5 is a top view of the guiding wheel of the retractable needle unit of FIG. 3, with the needle engaged in the needle guides in the retracted position. FIG. 6 is a top view of the guiding wheel of FIG. 3, with the needle engaged in the needle guides in the operative position.

FIG. 7 is a cross-sectional side view of the retractable needle unit.

FIG. 8 is a bottom view of the component shown in figure 4 mounted on a shaft, partially in cross-section. FIG. 9 is a bottom view of the component shown in figure 3 mounted on a shaft, partially in cross-section.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Referring to FIGs. 3 to 9, there is shown a retractable needle unit (10) for a punching apparatus having a punching roller (12) having a shaft (14), in accordance with a preferred embodiment of the invention.

The unit (10) includes a support wheel (16) rigidly mountable around the shaft (14). In order to make the support wheel (16) integral with the shaft (14), the support wheel has a threaded bore (18) extending radially therethrough, cooperating with a screw (20) or any other appropriate type of fastener. The screw is threaded through the bore (18) until it abuts on the shaft (14). Also preferably, the shaft (14) has a longitudinal notch (22) along its surface in which the end of the screw (20) is received, for better solidity. In the preferred embodiment, the screw (20) has a hexagonal head. The support wheel (16) has an annular face (24) extending within a radial plane. The unit (10) further includes a^* plurality of punching needles (26) mounted in a circular pattern on this annular face (24). Preferably, each of the punching needles (26) is L-shaped and defines a punching portion (28) and a mounting portion (30). The punching portion (28) extends in the radial plane, and the mounting portion (30) is insertable inside one of a plurality of holes (32) provided in the support wheel and distributed along the inner circumference of its annular face (24). Each of the punching needles (26) is pivotable in the radial plane between two positions; an operative position where it partially projects beyond the outer circumference of the support wheel (16) as shown in FIG. 6, and a retracted position where it lies within this outer circumference as shown in FIG. 5. The retractable needle unit (10) also includes a guiding wheel (34) which is, in operation, rotatably mounted around the shaft (14) in proximity to the support wheel (16). The guiding wheel (34) has a face (36) provided with a plurality of needle guides for engaging the punching needle (26). In this manner, rotating the guiding wheel (34) with respect to the support wheel (16) pivots the punching needles (26) between operative and retracted positions. Preferably, the face (36) of the guiding wheel (34) has a raised annular portion (40) provided with a plurality of cavities (38) therein defining the plurality of needle guides. In the preferred embodiment, each of the cavities (38) has an hourglass shape with first and second crossed axes (42) and (44). The first axis (42) is generally oriented along the radius of the guiding wheel (24), and thereby receives the corresponding punching needle (26) when it is in its operative position. The second axis (44) is oblique with respect to the first axis (42), to receive the corresponding punching needle (26) when in its retracted position.

The unit (10) finally includes locking means for locking the guiding wheel (24) with respect to the support wheel (16). The locking means are embodied by a threaded bore (46) and a screw (48). The threaded bore (46), is preferably provided through the guiding wheel (24), along a direction generally parallel to the radial plane and slanted with respect to the radius of the guiding wheel (24). The screw (48) is threaded through the bore (46) until it abuts against the shaft (14), preferably in the longitudinal notch (22). As before, the screw (48) is preferably a hexagonal head screw. In another considered embodiment, spring actuated means are used to lock the guiding wheel.

Referring to FIG. 2, according to a preferred embodiment, there are shown a plurality of retractable needle units (10) according to the invention mounted on the shaft (14) of a punching roller (12). The retractable needle units (10) are coaxially and rigidly mounted on the shaft (14). Preferably, a plurality of tightening members (52) are mounted on the shaft (14), one between each two adjacent retractable needle units (10), and in contact with both of these units (10). The tightening members (52) are made of a resilient material so that they act as a spring between the neighboring units, keeping a pressure applied on the guiding wheel when it is rotated so that the needles remain engage with the needle guides. In the preferred embodiment, each tightening member (52) comprises a circular portion coaxially disposed around the shaft (14) and having a wave-like shape in a direction parallel thereto. In the preferred embodiment, the needles are made of C1060 treated steel, the support and guiding wheels are made of conventional quick steel and the tightening members are made of a ring 1074 steel high in carbon provided with three longitudinal waves. All the other components described herein are of conventional design. It is of course understood that any other appropriate materials may be used to embody the present invention. Plastic may be particularly advantageous to mold the wheels, especially for mass production thereof.

Advantageously, the use of retractable needle units according to the present invention, considerably reduces the amount of time necessary to add or remove a row of needles from the punching roller shaft. Handling the apparatus is also safer and wrist injuries to the worker assigned to remove the needles are avoided. In addition, the quality of the perforation work is not damaged as it may be when frequent needle-handling is necessary.

Of course, numerous changes could be made to the preferred embodiments disclosed hereinabove without departing from the scope of the invention as defined in the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A retractable needle unit (10) for a punching apparatus having a punching roller (12) provided with a shaft (14), characterized in that it comprises: a support wheel (16) rigidly mountable around the shaft (14), said support wheel (16) having an annular face (24) extending within a radial plane; a plurality of punching needles (26) mountable in a circular pattern on the annular face of the support wheel (16), each of said punching needles (26) being pivotable in the radial plane between an operative position where it partially projects beyond an outer circumference of the support wheel (16) and a retracted position where it lies within said outer circumference; a guiding wheel (34) rotatably mountable around the shaft (14) proximate to the support wheel (16), said guiding wheel (34) having a face (36) provided with a plurality of needle guides therein for engaging each of said punching needles (26) so that a rotation of the guiding wheel (34) with respect to the support wheel (16) pivots the punching needle (26) between the operative position and the retracted position; and locking means for locking the guiding wheel (34) with respect to the support wheel (16).

2. A retractable needle unit (10) according to claim 1 , characterized in that: the support wheel (16) has a plurality of holes (32) therein for mounting the punching needles (26), said holes (32) being distributed along an inner circumference of the annular face (24); and each of the punching needles (26) defines an L-shape comprising a punching portion (28) for extending in the radial plane and a mounting portion (30) insertable inside one of the plurality of holes (32).

3. A retractable needle unit (10) according to claim 1 , characterized in that the locking means are embodied by a threaded bore (46) extending through the guiding wheel (34) along a direction generally parallel to the radial plane and slanted with respect to a radius of said guiding wheel (34), the locking means also comprising a screw (48) threadable through said bore (46) and abutable against the shaft (14) to lock the guiding wheel (34) with respect to the support wheel (16).

4. A retractable needle unit (10) according to claim 3, characterized in that the screw (48) is a hexagonal head screw.

5. A retractable needle unit (10) according to claim 3 in combination with the shaft (14) of the punching roller (12), characterized in that the locking means further comprise a longitudinal notch (22) extending in an outer surface of the shaft (14) for receiving an end of the screw (48) in abutment therewith.

6. A retractable needle unit (10) according to claim 1 , characterized in that the face of the guiding wheel has a raised annular portion (40) provided with a plurality of cavities (38) therein defining the plurality of needle guides.

7. A retractable needle unit (10) according to claim 6, characterized in that each of said cavities (38) defines an hourglass shape having first and second crossed axes (42 and 44), the first axis (42) being generally oriented along the radius of the guiding wheel (34) to receive the corresponding punching needle (26) when in its operative position, and the second axis (44) being oblique with respect to said first axis (42) to receive the corresponding punching needle (26) when in its retracted position.

8. A retractable needle unit (10) according to claim 7,characterized in that: the support wheel (16) is provided with a threaded bore (18) extending radially therethrough; and said retractable needle unit (10) comprises a screw (20) threadable through said bore (18) and abutable on the shaft (14) for rigidly mounting the support wheel (16) on said shaft (14).

9. A punching roller (12) for a punching apparatus, comprising a shaft (14), and characterized in that it further comprises: a plurality of retractable needle units (10) according to claim 1 , said retractable needle units (10) being coaxially and rigidly mounted on the shaft (14); and a plurality of resilient tightening members (52), each of said resilient tightening members being mounted on the shaft (14) between two adjacent retractable needle units (10) in contact with both of said adjacent needle units (10).

10. A punching roller (12) according to claim 9, characterized in that each of said resilient tightening members (52) comprises a circular portion coaxially disposed around the shaft (14), said circular portion having a wave-like shape in a direction parallel to said shaft (14).