GB2575460A

GB2575460A - Method for producing a waste saw segment and segment thus produced

Info

Publication number: GB2575460A
Application number: GB1811284.7A
Authority: GB
Inventors: Robert Kitching James
Original assignee: Fernite Of Sheffield Ltd
Current assignee: Fernite Of Sheffield Ltd
Priority date: 2018-07-10
Filing date: 2018-07-10
Publication date: 2020-01-15
Anticipated expiration: 2038-07-10
Also published as: GB2575460B; GB201811284D0

Abstract

A method of producing a heavy duty saw blade segment using an alloyed high speed band ( may be HS 6-5-3) of at least 20mm width, at least 5mm thickness and 50-100mm length, comprising a cutting edge and attachment edge, wherein the segment is machined down on both flanks by at least 1mm towards the cutting edge up to within 6mm of the cutting edge, wherein the remainder of both flanks is machined in a curved path reducing the cutting depth to zero at the edge, forming a flared edge, and wherein thereafter the flared edge is machined back by at least 1.3mm at regular intervals on one side (first side) of the flared edge, and regular intervals are machined on the other side (second side) but off set from the intervals of the first side, wherein teeth are then ground into the cutting edge.

Description

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BACK FACE

Method for producing a Waste Saw Segment and Segment thus obtained.

Saw blades for cutting up waste material of all sorts need to be made from extremely hard material to survive the wear and tear of production line cutting.

Such blades are mainly made from materials such as M42 or M3 steel and ground or milled to form teeth. Some are machined by passing a section of a large reel under a grinding wheel, others are first cut into sections and then machined.

Multi-purpose chopper blades are usually first cut into segments of about 100 mm since they are made from relatively thick steel which does not roll up willingly.

The inventors found that the availability of the M3 material increasingly scarce and a material available easily and in economic quantities was needed.

So a search for a better material was made and the inventor found a material which is an alloy of high speed steel and several other metals produced by powder metallurgical techniques.

An example of such a material is known as “HS 6-5-3” and is an alloy of chromium, molybdenum, tungsten, vanadium with high speed steel, which up to now has been little used in chopper blades, chiefly because of its price and formability with respect to setting.

Statement of the invention.

A method of producing a heavy duty saw blade segment wherein an alloyed high speed steel band of at least 20 mm width and of at least 5 mm thickness is cut into length of between 50 and 200 mm to form a sturdy chopper segment comprising a cutting edge and an attachment edge, which segment is then machined down on both flanks by at least 1 mm towards the cutting edge to within 6 mm of said cutting edge and wherein the remainder of both flanks is machined in a curved path reducing cutting depth to zero at the edge itself, thus forming a flared edge and wherein thereafter at regular off set intervals said flared edge is machined back by at least 1.3 mm on both flanks and wherein lastly teeth are created by machining said segment edge into an appropriate teeth shape thus producing a saw segment suitable for chopping up waste material of most consistencies.

As mentioned above, the chopper blank is made from alloyed high speed produced by a powder metallurgical process, such as “HS 6-5-3”.

It is produced in segments of between 50 and 200 mm in length, between 20 and 30 mm in height and between 6 and 8 mm in thickness. It comprises a cutting edge and an attachment edge.

Rather than set the teeth by bending as it is standard procedure, this chopper segment is milled on both flanks from the attachment edge up towards the cutting edge for approximately % of the way towards the cutting edge.

The last quarter is milled in a curve turning outward to arrive at the cutting edge at blank width, i.e. no machining at the cutting edge such that at the top of what will constitute the tip of the tooth, the segment will retain close to its starting thickness.

The same is repeated on the opposite face of the segment thus creating a flared segment which is then machined back on alternate sides to form throw for the saw teeth. The machined back areas form semi-circular depressions which determine the location of the saw teeth.

In this way, the chopper teeth are set without bending the material, which would damage the tooth structure and increase the likelihood of them breaking during production or operation.

To enable the segment to be conveniently mounted on the on the saw, apertures are drilled through the back of the segment, about 5 mm from the edge of the back. To increase the stability of the mount, a slot may be machined into the back of the segment which may cooperate with the apertures for a secure fixing.

Description of the Drawings.

Sheet 1 shows the segment prepared on one side only

Sheet 2 shows the segment prepared on both sides

Sheet 3 shows the segment completed except for the teeth

Sheet 1.

Figure 1(a) we see a side view of a segment, according to the invention, machined to a flaring taper on one flank and the semi-circular depressions machined in on the same flank and the position of the location apertures indicated.

Above figure 1 (a) we see a view onto the bottom (attachment edge) (fig 2 (a)), with the semicircular machining visible.

Figure 1 (b) represents a cross section on figure 1(a) along the line A-A showing the segment milled on one flank whilst figure 2(b) represents an end view on figure 2(a).

Figure 3 shows an enlargement of part B of figure 1 (B).

Sheet 2,

This sheet shows essentially the same views of the segment, side view (fig 4 (a), top view (fig 5 (a) and cross section (fig 5 (b), machined on both flanks.

Fig 4 (b) shows a cross section on figure 4 (a) along line A-A which highlights the semicircular machining and fig 6 shows an enlarged view of area B on that cross section.

Sheet 3,

Figures 7(a) and 7 (b) show the segment finished off, ready to have the teeth machined onto the cutting edge.

Figure 8 a slot machined into the main body of the segment to improve the location of the segment on a shredding machine.

Claims

Claims.

1. A method of producing a heavy duty saw blade segment wherein an alloyed high speed steel band of at least 20 mm width and of at least 5 mm thickness is cut into length of between 50 and 100 mm to form a sturdy chopper segment comprising a cutting edge and an attachment edge, which segment is then machined down on both flanks by at least 1 mm towards the cutting edge to within 6 mm of said cutting edge and wherein the remainder of both flanks is machined in a curved path reducing cutting depth to zero at the edge itself, thus forming a flared edge and wherein thereafter at regular off set intervals said flared edge is machined back by at least 1.3 mm on both flanks and wherein lastly teeth are created by grinding said segment edge into an appropriate teeth shape thus producing a saw segment suitable for chopping up waste material of most consistencies.

2. A method of producing a heavy duty saw blade according to claim 1 wherein the alloyed high speed steel is a powder metallurgical product known as HS 6-5-3

3. A method of producing a heavy duty saw blade according to claims 1 or 2 wherein said flared edge grinding creates a semi-circular depression at the cutting edge of said segment.

4. A method of producing a heavy duty saw blade according to any one or all of claims 1 to 3 wherein said semi-circular depressions on each flank of the segment are off set to each other such that each depression on one side is matched by non-depressed part on the opposite flank of the segment edge.

5. A method of producing a heavy duty saw blade according to any one or all of claims 1 to 4 wherein said teeth are machined into said cutting edge such that each tooth flares out of the plane of the segment in the opposite direction to its neighbour.

6. A method of producing a heavy duty saw blade according to any one or all of claims 1 to 5 wherein said segment comprises said cutting edge and said attachment edge, which attachment edge comprises apertures on the said segment’s flank near said attachment edge, opposed to the cutting edge, for attaching said segment to a cutting machine.

7. A method of producing a heavy duty saw blade according to any one or all of claims

1 to 6 said segment further comprises a slot rising from said attachment edge up towards said cutting edge for further securing said segment to a cutting machine.

8. A heavy duty saw bade segment formed from alloyed high speed steel band of at least 20 mm width and of at least 5 mm thickness is cut into length of between 50 and 100 mm is formed into a sturdy chopper segment comprising a cutting edge, an attachment edge and two flanks between said cutting edge and said attachment edge, each forming the surface between respective said cutting edge and attachment edge, which segment is then machined down on said flanks by at least 1 mm towards the cutting edge and to within 6 mm of said cutting edge and wherein the remainder of said flanks is machined in a curved path reducing cutting depth to zero at said cutting edge itself, thus creating a flared cutting edge and wherein thereafter at regular intervals said flared edge is machined back by at least 1.3 mm on alternate flanks and wherein lastly teeth are created by grinding said cutting edge into a toothed shape

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8. A heavy duty saw bade segment formed from alloyed high speed steel produced by the method of any one or all of the claims 1 to 7.

Amendments to the claims have been filed as follows:

Amended Claims.

1. A method of producing a heavy duty saw blade segment wherein an alloyed high speed steel band of at least 20 mm width and of at least 5 mm thickness is cut into length of between 50 and 100 mm to form a sturdy chopper segment comprising a cutting edge, an attachment edge and two flanks, each forming the surface between respective said cutting edge and attachment edge, which segment is then machined down on said flanks by at least 1 mm towards the cutting edge and to within 6 mm of said cutting edge and wherein the remainder of said flanks is machined in a curved path reducing cutting depth to zero at said cutting edge itself, thus forming a flared cutting edge and wherein thereafter at regular intervals said flared edge is machined back by at least 1.3 mm on alternate flanks and wherein lastly teeth are created by grinding said cutting edge into a toothed shape and so producing a saw segment suitable for chopping up waste material of most consistencies.

4. A method of producing a heavy duty saw blade according to any one or all of claims 1 to

3 wherein said semi-circular depressions on each flank of the segment are off set to each other such that each depression on one side is matched by non-depressed part on the opposite flank of the segment edge.

5. A method of producing a heavy duty saw blade according to any one or all of claims 1 to

4 wherein said teeth are machined into said cutting edge such that each tooth flares out of the plane of the segment in the opposite direction to its neighbour.

6. A method of producing a heavy duty saw blade according to any one or all of claims 1 to

5 wherein said segment comprises said cutting edge and said attachment edge, which attachment edge comprises apertures on the said segment’s flank near said attachment edge, opposed to the cutting edge, for attaching said segment to a cutting machine.

7. A method of producing a heavy duty saw blade according to any one or all of claims 1 to

6 said segment further comprises a lengthwise slot, rising from said attachment edge up towards said cutting edge for further securing said segment to a cutting machine.