WO2007030077A1

WO2007030077A1 - Shear blade

Info

Publication number: WO2007030077A1
Application number: PCT/SE2006/050315
Authority: WO
Inventors: Göran SKOOG
Original assignee: Uddeholm Machining Aktiebolag
Priority date: 2005-09-06
Filing date: 2006-09-05
Publication date: 2007-03-15

Abstract

11888 7 ABSTRACT The invention relates to a shear blade (1) for cutting an extrusion moulded body, for example an extrusion moulded body made of ceramics, plastics or metal, preferably extruded objects made of aluminium or cupper or alloys containing mainly aluminium or cupper, the shear blade comprising a front side (4), a back side (5), an upper end (6) 5 and a lower end (7), the front side being directed in the feed direction towards a front end of the extrusion moulded body and the back side being directed towards a rear end of the extrusion moulding body and towards an extrusion moulding matrix block, said shear blade comprising a shear blade holder (3) in the form of a guillotine-like plate (3) and a cutting portion (8) comprising a cutting edge (2) wherein said cutting portion 10 being detachably arranged to the holder portion.

Description

SHEAR BLADE

FIELD OF THE INVENTION

The present invention relates to a shear blade for cutting an extrusion moulded body, and more particularly an extrusion moulded body made of ceramics, plastics or metal, preferably extruded objects made of aluminium or cupper or alloys containing mainly aluminium or cupper, or other materials suitable for extrusion moulding. The shear blade comprising a front side, a back side, an upper end and a lower end, the front side being directed in the feed direction towards a front end of the extrusion moulded body and the back side being directed towards a rear end of the extrusion moulded body and towards an extrusion moulding matrix block, said shear blade comprising a shear blade holder in the form of a guillotine-like plate and a cutting portion comprising a cutting edge.

BACKGROUND INFORMATION

In extrusion moulding of ceramics, plastics or metals, the extruded object is cut at a certain length at the end of the operation when the rest part is cut off. For example, cutting of aluminium is difficult since the shear blade (cutting knife) is subjected to wear at the elevated temperature at which the operation takes place. Inadequate steel or design results in excessive damage to the shear blade. The result is increased cost for these blades and higher labour costs for changing the blade. In addition to this, worn and damaged shear blades results in lower yield since the extruded objects is damaged during the cutting. One must also consider the cost of downtime. Furthermore, changing the blades is a difficult job. It causes long interruptions that lead to decreased availability and poor plant performance.

The Japanese patent application with publication No. JP 07-205093, publication date 08.08.1995, disclose a cutting device for cutting extrusion moulded objects and comprises a pair of conveyors which move a moulded body in a feed direction, a cutting machine with a cutting blade moving up and down, said cutting blade being attached to an ultrasonic vibrator.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome the drawbacks and disadvantages of the above described shear blades for cutting an extrusion moulded body. This can be obtained by a shear blade which is characterised in that a cutting portion of the shear blade is detachably arranged to the holder portion of said shear blade. According to one aspect of the invention, plant performance can be increased and costs can be decreased.

According to another aspect of the invention, only the working part has to be changed which saves time as well as material.

According to still another aspect of the invention, the shear blade withstands abrasive wear and still the cost for the shear blade can be kept low.

According to yet another aspect of the invention, the shear blade has adequate hardness and abrasive wear resistance at elevated temperatures significant for the specific operation, which prolongs the time between each shutdown for changing the blade which leads to increased availability and better plant performance.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a view of a shear blade according to prior art,

Fig. 2 is a perspective view and an exploded view of a shear blade according to a preferred embodiment of the invention, and Fig. 3 is a side view of the cutting portion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 is a view of a shear blade 1 according to prior art. The shear blade is made of one solid plate with the cutting edge 2 and the holder 3 being integrated parts of the plate. When the cutting edge is worn, the complete shear blade has to be replaced.

Fig. 2 is a perspective view and an exploded view of a shear blade 1 according to a preferred embodiment of the invention. The shear blade 1 for cutting an extrusion moulded body, for example an extrusion moulded body made of ceramics, metal or plastics, comprises a front side 4, a back side 5, an upper portion 6 and a lower portion 7, the front side being directed in the moving direction towards the front end of the extruded body and the back side being directed towards the rear end of the extruded body, towards the extrusion moulding matrix block. Said shear blade comprises a shear blade holder 3, preferably in the form of a guillotine-like plate and a cutting portion 8 comprising a cutting edge 2. The cutting portion is detachably arranged to the holder portion. The coupling ends 9a, 9b of the holder and the cutting portion respectively are form fitted to one another and the cutting portion may be fastened to the holder by means of bolts or other appropriate fastening means. Preferably the cutting portion is fastened by countersunk bolts 10.

Fig. 3 is a side view of the cutting portion. Preferably, the back side of the cutting portion have a milled-out portion or recess 11 with a width that is adopted to the width of the extrusion moulded body in order to avoid direct contact between the cutting portion and the extrusion moulding matrix block in the area of the profile slot, whereby only the outer parts of the shear blade are in direct contact with and supported by the extrusion moulding matrix block during operation. The front side of the cutting portion is preferably designed in a conventional manner with a relief in order to facilitate the release of the cut off material.

In a preferred embodiment the cutting portion is made of tool steel having hardness of at least 52 HRC, preferably 52-54 HRC and in addition to this, the tool steel shall have excellent abrasive wear resistance at elevated temperatures. The holder portion can be made of a steel having a hardness of at least 46 HRC, preferably 46-48 HRC, and suitably the holder is made of a steel having less sophisticated properties than the steel of the cutting portion. However, it is to be understood that within the scope of the invention, it is possible to choose materials for the cutting edge portion and holder portion respectively thereby providing the shear blade any desired combination of properties adopted for cutting a specific material and also adapted to a specific cutting machine. Naturally other materials than steel may be used. In fact, the shear blade may be manufactured from other materials than metal, e.g. laminated wood, reinforced plastics, etc.

With a shear blade according to the invention, the cost for one unit is but half the cost and the time for changing the cutting edge is but 10% compared to the shear blade of prior art shown in fig. 1.

As will be understood by those skilled in the present field of art, numerous changes and modifications may be made to the above described and other embodiments of the present invention, without departing from its scope as defined in the appending claims. For example, the height and width as well as the thickness of the shear blade may be varied. The shear blade may be a solid plate, but it may also contain recesses or be perforated. Further, the holder portion may be assembled of several cooperative parts with different function, e.g. one part may transmit the cutting force to the cutting portion and another part may serve as coupling means to the actual moulding machine, etc. The holder portion may also comprise different layers of materials, e.g. inner and outer materials, with different properties. The cutting portion can be designed in any conventional manner depending on the form of the extruded object. The cutting edge need not be arranged in a horizontal way, a sloped cutting edge may be used. The coupling edges may be designed in another manner. The number of coupling means may vary and be placed in any appropriate way.

Claims

1. Shear blade (1) for cutting an extrusion moulded body, for example an extrusion moulded body made of ceramics, plastics or metal, preferably extruded objects made of aluminium or cupper or alloys containing mainly aluminium or cupper, the shear blade comprising a front side (4), a back side (5), an upper end (6) and a lower end (7), the front side being directed in the feed direction towards a front end of the extrusion moulded body and the back side being directed towards a rear end of the extrusion moulding body and towards an extrusion moulding matrix block, said shear blade comprising a shear blade holder (3) in the form of a guillotine-like plate (3) and a cutting portion (8) comprising a cutting edge (2) characterised in that said cutting portion being detachably arranged to the holder portion.

2. Shear blade according to claim 1, characterised in that the shear blade holder (3) is a guillotine-like plate.

3. Shear blade according to claim 1 characterised in that the cutting portion being made of a material having excellent hardness and anti erosion properties at elevated temperatures.

4. Shear blade according to claim 1 characterised in that the holder portion is provided with a holder coupling portion (9a) and the cutting portion is provided with a cutting coupling portion (9b), said coupling portions being form fitted to one another.

5. Shear blade according to claim 1 characterised in that the cutting portion is fastened to the holder by means of countersunk bolts (10).

6. Shear blade according to claim 1 characterised in that the back side of the cutting portion has a milled-out portion or recess (11) with a width that is adopted to the width of the extrusion moulded body in order to avoid direct contact between the cutting portion and an extrusion moulding matrix block in the area of a profile slot, whereby only outer parts of the shear blade are in direct contact with and supported by the extrusion moulding matrix block during operation.

7. Shear blade according to claim 1 characterised in that the cutting portion is made of tool steel having a hardness of at least 52 HRC, preferably 52-54 HRC, and excellent abrasive wear resistance at elevated temperatures.

8. Shear blade according to claim 1 characterised in that the holder portion is made of steel having a hardness of at least 46 HRC, preferably 46-48 HRC, and suitably the holder is made of steel having less sophisticated properties than the steel of the cutting portion.