GB1601470A - Mineral cutting picks - Google Patents

Description

(54) MINERAL CUTTING PICKS (71) We, WIMET LIMITED, a British company of Torrington Avenue, Tile Hill, Coventry CV4 9AD do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to picks for cutting minerals such as coal from a seam. The pick is mounted upon a disc, drum or chain and is traversed thereon across the coal or other mineral seam face by rotation of the drum or movement of the chain. Such a pick is replaceable and has a hard metal insert fixed in a head which has a shank formed integrally therewith.

In common use, there are two types of picks which are used on one disc or drum.

Some of the picks have sharpened cutting edges to cut the coal or other mineral but the remainder of the picks do not require sharpened cutting edges and are wedge shaped at their operative ends. The invention is concerned with picks which are shaped to provide both functions. This has the advantage that on a disc or drum, only one type of pick is used instead of two.

The object of the invention is to provide a mineral cutting pick in which the cutting action has maximum efficiency.

According to the invention a mineral cutting pick comprises a leading cutting edge defined at the junction of surfaces which meet an an obtuse included angle, and in which the leading cutting edge lies forwardly of a line joining the extremities of the leading cutting edge, in a direction in which the pick is traversed in use, and a pair of lines joining the extremities of the leading cutting edge to the point on the leading cutting edge which in use will be the first point to contact the mineral face meet at an included obtuse angle, the said surfaces merging into respective platforms terminating, at their respective outer edges, remote from said leading cutting edge, in sharpened cutting edges.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure I is a side view of a mineral cutting pick in accordance with the invention; Figure 2 is an enlarged side view of the insert of the pick shown in Figure 1; Figure 3 is a plan view of the insert as seen from the direction of the arrow 3 in Figure 2; Figure 4 is a cross-sectional view on the line 4-4 in Figure 2; and Figure 5 is a cross-sectional view on the line 5-5 in Figure 3.

The pick shown in Figure 1 is primarily intended for coal cutting and comprises a shank 10 for securement to a chain, disc, or drum which is moved or rotated so that the pick travels to the left as seen in Figure 1.

The pick has an integral head having a generally arcuate reinforcement 11. To the upper, outer corner of this head is fitted a hard metal cutting insert 12. Tungsten carbide or other hard material may be used for the insert, whereas the remainder of the pick is made from steel.

The insert has a complex form as seen in the drawings. The insert defines a leading cutting edge 13 which is flanked by a pair of convex surfaces 14, 15 which join at the leading cutting edge at an obtuse angle as shown in Figure 4. There are therefore a pair of lines joining the extremities of the leading cutting edge with the point on that edge which will, in use, be the first point on the leading cutting edge to contact the mineral face.

The leading cutting edge itself is convex as seen in Figures 1 and 2 with the leading portion being approximately midway along its length. The leading cutting edge 13 therefore lies forwardly of a line joining the extremities of this edge, in a direction in which the pick is traversed in use.

The surfaces 14, 15 merge into respective narrow platforms 16, 17 which are of arcuate form as seen from Figure 2. These platforms moreover terminate at their outer edges in respective sharpened edges 18, 19.

These edges are defined by substantially flat sides 20, 21 of the insert which as seen in Figure 4 converge in a direction away from the leading cutting edge 13.

The platforms 16, 17 run out to a line defined by the termination of the surfaces 14, 15 respectively such line being identified in Figure 2 at 22. The point at which platforms run out coincides also with the terminations of sides 10, 21 such termination being identified in Figures 2 and 5 at 23 and 24 respectively.

The insert also has two surfaces 25, 26 joining at a further edge 27 which forms the outermost extremity of the head of the pick.

The surfaces 25, 26 are convex in the plane of the section of Figure 5 as seen in that Figure.

Portions of the head adjacent to the insert 12 have surface configuration merging with or being substantially co-planar with those on the insert. Continuations of the surfaces 14, 15 are formed by zones of which one is identified in Figure 1 and 2 at 28.

In an alternative construction, the convex surfaces 14, 15 and 25, 26 are flat in the plane seen in the crossectional views in Figures 4 and 5.

The platforms 16. 17 may be disposed with positive, negative or zero cutting rakes.

giving differing inclinations to the edges of the insert respectively, and furthermore may be convex as viewed in Figure 2 or straight edged and therefore flat.

WHAT WE CLAIM IS: 1. A mineral cutting pick comprising a leading cutting edge defined at the junction of surfaces which meet at an obtuse included angle, and in which the leading cutting edge lies forwardly of a line joining the extremities of the leading cutting edge, in a direction in which the pick is traversed in use, and a pair of lines joining the extremities of the leading cutting edge to the point on the leading cutting edge which in use will be the first point to contact the mineral face, meet at an included obtuse angle, the said surfaces merging into respective platforms terminating at their respective outer edges, remote from said leading cutting edge, in sharpened cutting edges.

2. A mineral cutting pick as claimed in claim 1 in which said surfaces which meet to define said leading cutting edge are convex, the leading cutting edge being of convex curvature.

3. A mineral cutting pick substantially as hereinbefore described with reference to and as shown in the accompanying draw ings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. extremities of this edge, in a direction in which the pick is traversed in use. The surfaces 14, 15 merge into respective narrow platforms 16, 17 which are of arcuate form as seen from Figure 2. These platforms moreover terminate at their outer edges in respective sharpened edges 18, 19. These edges are defined by substantially flat sides 20, 21 of the insert which as seen in Figure 4 converge in a direction away from the leading cutting edge 13. The platforms 16, 17 run out to a line defined by the termination of the surfaces 14, 15 respectively such line being identified in Figure 2 at 22. The point at which platforms run out coincides also with the terminations of sides 10, 21 such termination being identified in Figures 2 and 5 at 23 and 24 respectively. The insert also has two surfaces 25, 26 joining at a further edge 27 which forms the outermost extremity of the head of the pick. The surfaces 25, 26 are convex in the plane of the section of Figure 5 as seen in that Figure. Portions of the head adjacent to the insert 12 have surface configuration merging with or being substantially co-planar with those on the insert. Continuations of the surfaces 14, 15 are formed by zones of which one is identified in Figure 1 and 2 at 28. In an alternative construction, the convex surfaces 14, 15 and 25, 26 are flat in the plane seen in the crossectional views in Figures 4 and 5. The platforms 16. 17 may be disposed with positive, negative or zero cutting rakes. giving differing inclinations to the edges of the insert respectively, and furthermore may be convex as viewed in Figure 2 or straight edged and therefore flat. WHAT WE CLAIM IS:

1. A mineral cutting pick comprising a leading cutting edge defined at the junction of surfaces which meet at an obtuse included angle, and in which the leading cutting edge lies forwardly of a line joining the extremities of the leading cutting edge, in a direction in which the pick is traversed in use, and a pair of lines joining the extremities of the leading cutting edge to the point on the leading cutting edge which in use will be the first point to contact the mineral face, meet at an included obtuse angle, the said surfaces merging into respective platforms terminating at their respective outer edges, remote from said leading cutting edge, in sharpened cutting edges.

2. A mineral cutting pick as claimed in claim 1 in which said surfaces which meet to define said leading cutting edge are convex, the leading cutting edge being of convex curvature.

3. A mineral cutting pick substantially as hereinbefore described with reference to and as shown in the accompanying draw ings.