SE528041C2 - Rotary knife and rotary knife unit with such a rotary knife - Google Patents

Abstract

A rotary cutter drum includes a cutter portion formed of a multiphase material and includes first and second substantially cylindrical, radially outwardly exposed surfaces, and a knife member formed of one piece with the exposed surfaces and arranged to axially separate the first and second surfaces from one another. The knife member protrudes by a distance in the range of 1 to 5 mm radially outwardly beyond a smallest diameter portion of the first and second exposed surfaces. The knife member includes two sides terminating at respective ones of the first and second exposed surfaces.

Description

30 528 041 2 extends 6-14 mm yt from the surface Ea and forms an edge in said peripheral part. The rotary knife roller B is provided with a shaft G arranged to be connected to a drive unit, such as an electric motor (not shown).

Peripherally to the surfaces Ea., Eb

In addition, the abutment parts Ha, Hb have a diameter which is substantially the same as the radially peripheral part of said knife part F. The annular parts Ha, Hb are arranged to abut against and to transmit the rotation of the rotary knife roller B to said support roller C in such a way that it rotates in the direction opposite to the direction of rotation of the rotary knife roller B.

Fig. 6 shows the surfaces Ea, Eb covered with steel, plastic or rubber inserts Yes, Jb attached to the surfaces Ea, Eb with screws K. , 5 mm to 5 mm. Radially directed holes La are formed in the inside of the body of the knife part. Corresponding aligned holes Lb are made in the posts Yes. Holes Lc are also formed in the knife part D on the outside of the knife part F. In-line holes Ld are also formed in corresponding positions of said insert Jb.

The holes La, Lb and Lc, Ld communicate with axially extending channels Mi mentioned body, the holes La, Lb and Lc, Ld being optionally connected to a vacuum and / or a source of overpressure (alternatively atmospheric pressure) by means of a control unit (not shown) with suitable valves.

The holes La and Lc are provided with seals (not shown), such as O-rings or any kind of gasket suitable for sealing against the inserts Ja, Jb, so that leakage between the insert and the surface Ea and Eb, respectively, is avoided. 528 041 20 25 Rollers B, C rotate in the direction indicated by arrows in fi g. 5. A web N is introduced into the rotating knife unit A between the rollers B and C. The holes La, Lb and Lc, Ld i are checked to be connected to a vacuum source, so that the web adheres to the insert J a 'covering the surface Ea. With continued rotation, the knife cuts the fabric into the shape of the knife part.

Essentially at the same time, the holes La, Lb are controlled to be connected to overpressure or atmospheric pressure, so that the cut product detaches from the insert J a and is allowed to be transported by e.g. a conveyor belt not shown. The holes Lc, Ld are still exposed to vacuum, so that the clip P, i.e. the remainder of the fabric which is allowed to stick to the insert Ib covering the surface Eb in such a way that the clip is allowed to continue its rotation together with the roller B. When the cut-out articles Q have been securely separated from the clip, the holes Lc, Ld are connected to overpressure or atmospheric pressure, so that the clip P can be detached and collected. I Instead of screwing the inserts Ja, Jb on the surfaces Ea, Eb, these can be glued to them. In such cases, the insert may also be made of foam.

US-A-5 967 009 discloses a rotating knife with a roller made of steel provided with a number of knives formed in one piece on the roller. This type of roller is disadvantageous because the knife has limitations in its size, as a knife of this type and protruding more than 1A inch (6.25 mm) would cause a too large torque on the knife, which in turn causes cracks in steel, while a knife protruding less than 0.1 inch (2.5 mm) cannot be machined.

SUMMARY OF THE INVENTION The object of the invention is to obtain a less complex rotary writing device. 528 041 10 20 25 30 4 This object is solved in that a sleeve with an inner surface delimiting an inner diameter is made of a solid material, such as cemented carbide, ceramics or metallic powder and comprises at least said section.

This results in that the inserts can be eliminated, less machining of the knife part and that only a limited amount of asm erase material is needed.

Suitably the knife part comprises a pair of edges and an inclined section extending from the respective edge towards said respective surfaces, said inclined section extending at least 50% of the radial extent of the knife part. Alternatively, the inclined section extends substantially the entire radial extent of the knife part. In this way it is obtained that grinding can be performed in a faster and easier way; sharp corners are avoided. In addition, a longer life of the edge is obtained and thus also a longer life of this.

It should be noted that the edge forms an abutment surface that may not be visible to the eye, as it may have an extent that is fractions of a rnillirneter.

Preferably, a number of openings formed in the knife section are arranged to be associated with a gas source with a controllable pressure, wherein at least one opening is arranged substantially at said knife part. This makes it possible to provide the surface with more holes than before and a wider possibility of obtaining a desired hole distribution, so that a more efficient connection of the fabric and a more efficient detachment of the cut article and / or the clip from the surface can be obtained. In addition, leakage between the surface and the steel inserts is eliminated.

Suitably, at least one annular part is arranged to abut against a rotatable support roller, the annular part having a diameter which extends substantially to the same extent above the surface of the knife part. In this way an optimal contact is obtained between the annular part and the support roller and between the knife part and the roller. Preferably, said at least one knife section and said at least one annular section are integral parts of a single sleeve having an inner surface defining an inner diameter, said sleeve being adapted to be arranged on a shaft.

Alternatively, said at least one knife section and one of said annular sections form an integral part, while the second annular part forms a separate part of a sleeve with an inner surface delimiting an inner diameter, said separate parts being adapted to be arranged on a shaft for forming of said sleeve.

Alternatively, said at least one knife section and said at least one annular part are separate parts of a sleeve with an inner surface defining an inner diameter, said separate parts being adapted to be arranged on a shaft to form said sleeve. This gives different possible rotation knives.

A wall thickness of said sleeve is defined by the difference between the diameter of the inner surface and that of the first and second outer surfaces having the smallest diameter, said wall thickness being in the range 1 cm to 10 cm. As a result, less material is needed for the manufacture of the rotary knife device compared with previously known rotary knives.

DRAWING SUMMARY In the following, the invention will be described in further detail with reference to the accompanying drawing, in which fi g. 1A-1D illustrate a rotational line: fi g. 2 is an enlargement of a section of a rotary knife roller according to any one of fi g. 1A-ID; fi g. 3 and 4 are schematic illustrations of variants of knife parts; and fi g. 5-6 illustrate a prior art rotary unit. DETAILED DESCRIPTION Fig. 1A shows a rotary knife roller 4 made of a curing material, such as a cemented carbide, core or metallic powder in a drive relationship with a rotatable support roller 6.

The roller 4 is solid and has at least one knife part 10 and a pair of annular abutment parts 12a, 12b, produced in one piece from a solid material, such as cemented carbide or ceramic. The rotating body roller 4 is provided with a knife section 8 with surfaces 9a, 9b on each side of at least one knife part 10 projecting from the surfaces 9a, 9b, the radially peripheral part of the body part 10 having a diameter greater than the diameter of surfaces 9a and 9b, respectively.

The knife part 10 extends 6-14 mm on the surface 9a and forms an edge at said peripheral part. The rotary knife roller 4 is provided with a shaft 11 arranged to be connected to a drive unit, such as an electric motor (not shown).

Peripheral to the surfaces 9a, 9b are arranged a pair of annular abutment parts 12a, 12b which have a diameter which is larger than the surfaces 9a, 9b of the knife section 8.

In addition, the abutment members 12a, 12b have a diameter substantially the same as the radially peripheral portion of the knife member 10. The annular abutment members 12a, 12b are arranged to abut and transmit rotation of the rotary knife roller array 4 to said support roller 6 so that it is rotated in a direction opposite to the direction of rotation of the rotary knife roller 4.

Radially directed heels 16a are formed in the body on the inside of the knife part 10. Holes 16b are also formed in the knife section 8 on the outside of the knife part 10. 528 041 10 15 20 25 30 7 The holes 16a, 16b communicate with axially extending channels 18 in said body , the holes 16a, 16b being optionally connected to a source of vacuum and / or for overpressure (alternatively atmospheric pressure) by means of a control unit (not shown) with suitable valves.

Fig. 1B shows a rotary blade roller 4 according to a first embodiment of the invention adapted to be arranged in operating relationship with a rotatable support roller 6 and to form a rotary knife unit. According to this embodiment, the roller 4 consists of a shaft part 17a and a sleeve part 17b, the sleeve part having a knife section 8 with at least one knife part 10 and a ring-shaped bearing part 12a, 12b on each side of the knife section 8.

The shaft part 11 is preferably made of steel, while the sleeve part is preferably made of a solid material. The sleeve part 17b has an inner surface 17c, the diameter of which is slightly smaller than the diameter of the outer surface 17d of the shaft part 17a.

The sleeve part 17h is mounted on the shaft part 17a 'with a press fit. This is done by exposing the shaft part 17a to a cold environment so that it shrinks, after which the sleeve part 17b can be easily pushed onto the shaft part 17a, and the corresponding holes on the sleeve part and the shaft part can be easily aligned with each other.

When the sleeve part 17b needs maintenance, Lex. due to a dull knife part 10, the sleeve part 17b is pushed off the shaft part 17a after cold treatment.

As shown in fi g. IC, the sleeve part 17b can be divided into three parts, i.e. a knife part 17e comprising a knife section 8 and two separate parts 17f, 17 g, comprising adjacent abutment parts 12a, 12b.

As shown in fi g. 1D, the sleeve section 17b may instead be divided into two parts, i.e. in the knife section 8 and one of the abutment parts 12a, constituting a part 17h and a separate part 17i, comprising the other of the abutment parts 12b. 528 041 20 25 8 Fig. 2 shows a knife part 10, the surfaces 9a, 9b and one of the annular abutments in the egg parts 12a in accordance with any of the embodiments shown in fi g. 1A-ID.

The knife part 10 extends in the range 1 mm to 5 mm radially above the surface 92t-D61! annular abutment portion 12a extends substantially in the corresponding circumference above the surface 9a as the knife portion 10. However, the difference in radial extent may be e.g. -0.5 mm to 0.5 mm depending on the material of the fabric to be cut. This difference is shown as a positive value in fi g. 3 and 4 and has been given the designation 19.

The reason operation in the embodiments showed in fi g. 1A-ID is performed in the manner described in connection with fi g. 5 and 6 above with respect to the prior art.

As shown in fi g. 2, however, it is also possible to form the holes 16a, 16b near the knife part 10, which would be impossible with the rotating knife of the prior art shown in fi g. 5 and 6, as this would cause leakage problems between the inserts 14a, 14b and the surfaces 9a, 9b.

As shown in fi g. 3, the knife part 10 comprises a pair of cutting edges 20a, 20b separated from an abutment surface 20c. On each side of the edges 20a, 20b, a side section 21 extends to the surfaces 9a and 9b, respectively. The side section 21 includes a sloping section 22 and a raised section 24 to simplify the manufacture of the edge in such a way that its strength is optimal. It should be noted that the abutment surface 20c may or may not be visible to the eye, i.e. be in the range between pm and 0.5 mm.

According to fi g. 4, the knife part 10 comprises an inclined section 22 and a substantially radially extending section 26. However, the radially extending section constitutes less than half the height d of the knife part 10.

Claims (10)

10 20 25 30 528 041 PATENT REQUIREMENTS A rotary writing device for a rotary knife apparatus (2), including at least one knife section (8) having a first and a second substantially circular-cylindrical outer surface (9a, 9b), said knife section (8) comprising at least one knife part (10) protruding from and dividing said first and second surfaces (9a, 9b), said first and second surfaces (9a, 9b) and said knife part (10) forming integral parts of said knife section (8), the knife part (10) extending radially in the range 1 to 5 mm above that of the first and second surfaces (9a, 9b) having the smallest diameter, are characterized! in that a sleeve (17b) with an inner surface delimiting an inner diameter is made of a solid material, such as cemented carbide, ceramics or metallic powder, and comprises at least said knife sections (8). A rotary knife device according to claim 1, wherein the knife part (10) comprises a pair of edges (20a, 20b) and an inclined section (22) extending from the respective edge (20a, 20b) towards said respective surfaces (9a, 9b), said inclined section extending at least 50% of the radial extent of the knife part. A rotary knife device according to claim 2, wherein the inclined section (22) extends substantially the entire radial extent of the knife part (10). A rotary blade device according to any one of claims 1 to 3, wherein a plurality of openings (16a, 10c) are formed in the knife section (8) arranged to be associated with a gas source with a controllable pressure, wherein at least one opening (16a, 16b) is arranged substantially at said knife part (10). A rotary knife device according to any one of claims 1 to 4, wherein at least one annular section (12a, 12b) is arranged to abut against a rotatable support roller (6), the annular section (12a, 12b) having a diameter extending substantially to the same extent above the surface (9a, 9b) of the knife part (10). 528 041 '10 15 20 10 A rotary knife device according to claim S, wherein said knife section (8) and said annular section (12) are integral parts of a single sleeve (17b), said sleeve being adapted to be arranged on a shaft (11). A rotary housing device according to claim 5, wherein said knife section (8) and one of said annular sections (12) form an integral part (171), while the other annular section (12) constitutes a separate part (17g) of a sleeve (17g). 17b) with an inner surface delimiting an inner diameter, said separate parts (17c, 17d, 17e) being adapted to be arranged on a shaft (11) to form said sleeve (17b). A rotary blade device according to claim 5, wherein said at least one knife section (8) and said annular section (12) are separate parts (17c, 17d, 17e) of a sleeve (17b) having an inner surface defining an inner diameter, said separate parts (17c, 17d, 17e) being adapted to be arranged on a shaft (1 1) to form said sleeve (17b). A rotary knife device according to claim 6, 7 or 8, wherein a wall thickness of said sleeve (17b) is defined by the difference between the diameter of the inner surface and that of the first and second outer surfaces (9a, 9b) having the smallest diameter, wherein said wall thickness is in the range of 1 cm to 10 cm. A rotary writing apparatus comprising a support roller (6) characterized in that it comprises a rotary knife device (4) according to any one of the preceding claims.