GB2053315A - Cutter pick and pick mounting combinations for mining machines - Google Patents

Abstract

A cutter pick and pick mounting combination for use on a cutter head of an underground mining machine comprises a pick having a head (1) provided with two oppositely directed cutting portions (9 and 11) associated with two alternative pick cutting positions, respectively, and a shank (15) mounted in a passage (20) provided in the pick mounting comprising a pivotal arrangement (25) provided in a pick mounting box (2), in use pivotal movement of the pick carrying pivotal arrangement being prevented beyond the two alternative cutting positions by the shank contacting the passage wall (22 or 24). <IMAGE>

Description

SPECIFICATION Cutter pick and pick mounting combinations for mining machines This invention relates to cutter pick and pick mounting combinations for mining machines.

In particular the present invention relates to cutter pick and pick mounting combinations in which the cutter pick is adapted to cut in two opposed cutting directions and the pick mounting permits the pick to move between two operational modes associated with the two opposed cutting directions, respectively.

It is known in a cutter pick and pick mounting combination used with a rotary cutter head which repeatedly traverses to and fro across a working rock or mineral face and which reverse the direction of rotation at the end of each traverse for the pick to have two opposed cutting portions and for the pick to pivot in its mounting upon the reverse of rotation of the cutter head enabling the pick to take up a desired cutting position relative to the working face in which it cuts a necessary clearance for that portion of the pick following behind the current cutting position of the pick.

Unfortunately, such known cutter pick and pick mounting combinations tend to involve intricate pick mounting mechanisms which tend to be unsuitable for use in the dirty and arduous conditions encountered in underground mining and which tend to have relatively short operational lives.

An object of the present invention is to provide a cutter pick and pick mounting combination which tends to overcome or reduce the above mentioned problems.

According to the present invention a cutter pick and pick mounting combination for use on a cutter head on a mining machine comprises a cutter pick having a head provided with two oppositely directed cutting portions, shank extending from the head, and an abutment, and a pick mounting comprising a box fixedly securable to the cutter head and defining a passage for receiving the shank and providing a formation for engagement by the abutment when, in use, the pick is fully inserted in the passage, and a pivotal arrangement mounted at least partly within the box to carry the pick in two alternative cutting positions associated with the two oppositely directed cutting portions, respectively, in use, pivotal movement of the pick carrying pivotal arrangement being prevented beyond the two alternative cutting positions by the shank contacting the passage wall.

Preferably, the pivotal arrangement comprises a generally cylindrical member slidably engaged in a cross bore formed in the box, the axis of the cross bore being transverse to the axis of the passage.

Advantageously, the generally cylindrical member is retained within the cross bore by an end cap closing the cross bore.

Preferably, the generally cylindrical member has an abutment portion providing the formation for engagement by the abutment.

Conveniently, the generally cylindrical member has a through passage for receiving a portion of the pick shank.

Preferably, pivotal movement of the pick when carried by the pivotal arrangement is prevented when a portion of the shank remote from the head abuts the passage wall.

Conveniently, the portion of the shank remote from the head alternatively abuts two sides of the passage wall to prevent pivotal movement of the pick depending upon the cutting position of the pick.

Advantageously, the portion of the passage wall contacted by the pick is on the side of the pivotal arrangement remote from the head.

Preferably, the first mentioned passage extends through the box.

Preferably, the pick has two abutments for abutting formations provided by the pick mounting.

Advantageously, the abutments are constituted by shoulders formed at the junction of the pick head and shank.

Preferably, pick locking means are provided to releasably retain the pick in the pick mounting.

By way of example only, one embodiment of the present invention will be described with reference to the accompanying drawings, in which: Figure 1 is a side view of a cutter pick and pick mounting combination constructed in accordance with the present invention, the pick being shown in one of two alternative operational positions; Figure 2 is a part section of the pick mounting taken along line Il-Il of Figure 1, the pick not being shown in section and being positioned midway between its two alternative operation cutting positions; and Figure 3 is an incomplete perspective view of the combination of Figure 1 , the combination being viewed from below.

Referring to the drawings, a cutter pick 1 is shown fully inserted in a pick mounting 2 comprising a pick box 3 welded to a cut rock or mineral loading vane 4 (only a part of which is shown in Figures 2 and 3) constituting part of a rotary cutter head mounted on a mining machine.

In use, the cutter head is repeatedly traversed to and fro across a rock or mineral working face 5 (only the adjacent portion of which is shown) to win rock or mineral from the face. When the cutter head reaches the end of a traverse along the working face its direction of rotation is reversed before the cutter head is traversed along the working in the opposite direction.

The cutter head will have a plurality of pick boxes 3 and associated cutter picks 1 arranged around the cutter head in a desired pattern. As will be explained later in the specification the pick has two alternative cutting positions depending upon the direction of rotation of the cutter head.

The cutter pick 1 comprises a head 8 provided with two oppositely directed cutting portions 9 and 11 each presenting a cutting tip of relatively hard wearing material, for example tungsten carbide. The head is also provided with a cross pin 12 enabling an extraction tool (not shown) to grip the head to withdraw the pick from the pick box.

A shank 15 extends from the head 8 and two abutment shoulders 16 and 1 7 are formed at the junction of the shank with the head, the abutment shoulders abutting formations 34 and 35 respectively provided on the pick mounting when the pick is fully inserted in the pick box.

The pick box 3 defines a through passage 20 for accommodating the pick shank 15, the surface side portions 22 and 24 of the passage wall which are alternatively contacted by the shank depending upon the cutting position of the pick are inclined outwardly towards the end of the passage remote from pick box recess formations 1 8 and 1 9 which provide clearance pockets on opposite sides of the pick head tending to ensure no cut rock or mineral becomes trapped between the pick and the pick box so as to hinder movement of the pick between its two operational cutting modes.

A pivotal arrangement 25 mounted within the pick box 3 comprises a generally cylindrical member 26 having a through passage 27 for accommodating the pick shank and two cylindrical bearing portions 28 and 29 slidably engaged in a cylindrical cross bore 30 formed in the pick box, the longitudinal axis of the cross bore 30 being substantially normal to the longitudinal axis of the passage 20. The generally cylindrical member 26 is retained in the cross bore 30 by an end cap 31 welded to the box and closing the cross bore.

The generally cylindrical member presents two abutment shoulders 34 and 35 which are contacted by the abutments 1 6 and 1 7 on the pick to retain the pick in its fully inserted position throughout cutting and which absorb a substantial proportion of forces exerted along the axis of the pick during cutting.

A pick locking device (not shown) is provided to retain the pick 1 in the fully inserted position.

In operation, with the cutter head traversing along the working face and rotating in a clockwise direction as seen in Figures 1 and 3, the cutter pick 1 is urged to take up the position as seen in Figures 1 and 2 with the shank contacting the side portion 22 of the passage wall and retaining the pick in position with the cutting portion 9 engaging the working face against the reaction exerted on the pick by the winning of rock or mineral from the working face 5. All the picks on the cutter head will be in a similar position to the pick shown in Figures 1 and 3.

Upon the cutter head reaching the end of its traverse along the working face, its direction of rotation is reversed ie to an anticlockwise direction as seen in Figures 1 and 3 and each cutter pick 1 is urged towards its other operational cutting position with the cutting portion 11 engaging the working face. The reaction between the working face and the pick causes the pick together with the pivotal arrangement 25 to pivot in a clockwise direction as seen in Figures 1 and 3.

The pick is carried by the pivotal arrangement until the shank contacts the side portion 24 of the passage wall. Further clockwise pivotal movement of the pick is prevented. During the time the pick is carried by the pivotal arrangement the abutments 1 6 and 1 7 are abutting the abutment shoulders 34 and 35 of the pivotal arrangement.

During pivotal movement of the pivotal arrangement 25 the cylindrical members 28 and 29 slide around the circumference of the cross bore 30.

When the cutter head reaches the opposite end of its traverse and its rotational direction once again is reversed the cutter picks are urged to take up a position as indicated in Figures 1 and 3.

From Figures 1 and 3 it can be seen that one side wall of the pick box is cut away at 37 and 38 to facilitate the passage of any small pieces of rock or coal which may pass along the passage 20 when the cutter pick is being replaced. Also, the cut away side wall portions tend to expose the base of the pick shank (as seen in Figure 3) which will assist removal of the pick should the cross pin 12 become damaged.

From the above description it will be seen that the present invention provides a simple and robust cutter pick and pick mounting combination.

Claims (12)

1. A cutter pick and pick mounting combination for use with a cutter head on a mining machine comprising a cutter pick having a head provided with two oppositely directed cutting portions, shank extending from the head, and an abutment, and a pick mounting comprising a box fixedly securable to the cutter head and defining a passage for receiving the shank and providing a formation for engagement by the abutment when, in use, the pick is fully inserted in the passage, and a pivotal arrangement mounted at least partly within the box to carry the pick in two alternative cutting position associated with the two oppositely directed cutting portions, respectively, in use, pivotal movement of the pick carrying pivot arrangement being prevented beyond the two alternative cutting positions by the shank contacting the passage wall.

2. A combination as claimed in claim 1, in which the pivotal arrangement comprises a generally cylindrical member slidably engaged in a cross bore formed in the box, the axis of the cross bore being traverse to the axis of the passage.

3. A combination as claimed in claim 2, in which the generally cylindrical member is retained within the cross bore by an end cap closing the cross bore.

4. A combination as claimed in claim 2 or 3, in which the generally cylindrical member has an abutment portion providing the formation for engagement by the abutment.

5. A combination as claimed in claim 2, 3 or 4, in which the generally cylindrical member has a through passage for receiving a portion of the pick shank.

6. A combination as claimed in any one of the preceding claims, in which pivotal movement of the pick when carried by the pivotal arrangement is prevented when a portion of the shank remote from the head abuts the passage wall.

7. A combination as claimed in claim 6, in which the portion of the shank remote from the head alternatively abuts two sides of the passage wall to prevent pivotal movement of the pick depending upon the cutting position of the pick.

8. A combination as claimed in claim 7, in which the,portion of the passage wall contacted by the pick is on the side of the pivotal arrangement remote from the head.

9. A combination as claimed in claim 8, in which the first mentioned passage extends through the box.

1 0. A combination as claimed in any one of the preceding claims, in which the pick has two abutments for abutting two formations provided by the pick mounting.

1 A combination as claimed in claim 10, in which the abutments are constituted by shoulders formed at the junction of the pick head and shank.

12. A combination as claimed in any one of the preceding claims, in which pick locking means are provided to releasably retain the pick in the pick mounting.

1 3. A cutter pick and pick mounting combination substantially as described herein and as shown in the accompanying drawings.