GB2072241A

GB2072241A - Pick box

Info

Publication number: GB2072241A
Application number: GB8105167A
Authority: GB
Original assignee: Hall and Pickles Ltd
Current assignee: Hall and Pickles Ltd
Priority date: 1980-03-07
Filing date: 1981-02-18
Publication date: 1981-09-30
Also published as: GB2072241B

Abstract

A pick box 1 having an aperture 5 to receive the shank of a replaceable mineral cutting pick, comprises a body member 2, a generally rectangular aperture 5 provided in the body member 2, extending inwardly from an open mouth 8 at one end 4 of the body member 2 and serving to receive a pick shank of generally rectangular cross-section, the aperture 5 having an enlarged, lead-in portion 10 that extends inwardly from the open mouth 8, is provided in at least one side 6 of the aperture 5 and extends over part of the length of the aperture 5. <IMAGE>

Description

SPECIFICATION Pick box This invention relates to a pick box which is apertured to receive the shank of a replaceable, mineral cutting pick, the shank conventionally extending from an integral carbide tippped head.

Such pick and pick box combinations are commonly employed in coal mining operations e.g. by welding the box onto a spiral vane rotary cutting drum of a mining machine; or in underground roadway driving operations, e.g. by welding the box onto a rotatable cutting head of a roadway driving machine; or in civil engineering being part of a road surface planing machine.

Because of the severe working conditions, mineral cutting picks usually have to be replaced daily, and various latching arrangements have been proposed for releasably retaining the pick shank in the aperture. One such latching arrangement is shown in British Patent 1,557,398 where a resilient latching member is located towards the end of the pick shank remote from the pick head, a multiple toothed.surface projecting beyond the adjacent shank surface and adapted to engage behind a shoulder provided in the pick box, the particular part of the toothed surface which effects engagement being determined by the extent of penetration of the shank into the pick box aperture. Such penetration is not critical and varies according to the amount of wear on any particular pick box and/or pick.It will be appreciated that with the limits on space and visibility imposed by mining conditions, removal of a worn pick and insertion of a replacement pick should be made as easy as possible, but difficulties are sometimes encountered initially forcing the toothed surface of the resilient latching member of a replacement pick into the aperture, and thereby compressing the teeth of that surface until, after the shank has been pushed fully into the aperture, the pick is latched in position with certain leading teeth passing the shoulder, other intermediate teeth engaging the shoulder, and yet other, trailing teeth remaining compressed within the aperture.

According to the present invention, a pick box having an aperture to receive the shank of a replaceable cutting pick comprises a body member, a generally rectangular aperture provided in the body member, extending inwardly from an open mouth at one end of the body member and serving to receive a pick shank of generally rectangular cross-section, the aperture having an enlarged, lead-in portion that extends inwardly from the open mouth, is provided in at least one side of the aperture and extends over part of the length of the aperture.

Thus, due to the provision of the enlarged, leadin portion, the aperture in the pick box does not immediately compress the teeth of the resilient latching member, and therefore the shank may be always readily inserted into the aperture, over a distance corresponding to the length of the lead-in portion, so that only after the shank finds some support from the lead-in portion can deformation of the teeth commence upon further insertion of the shank. In practice, this means that the end of the shank may be readily inserted into the lead-in portion of the aperture, and the pick driven home by a blow from a hammer.

An enlarged, lead-in portion may be provided in one sidewall only of the aperture, if the shank is of a kind where the resilient latching member projects from one side only thereof, or alternatively, an enlarged, lead-in portion may be provided in each of two opposite sidewalls of the aperture if the shank is of a kind where the resilient latching member projects from two, opposite sides thereof.

Conventionally, the aperture is formed in the body member by drilling a hole through the body member in the direction in which the aperture is to extend, with the hole subsequently expanded from this circular section to the required rectangular section by broaching. Conventionally therefore, the enlargement may be produced by counterboring the previously drilled hole, to provide a lead-in portion of slightly greater diameter than the drilled hole, and capable therefore of accommodating a shank with a resilient latching member projecting to one side, or to two opposite sides of the shank.

The aperture is preferably oblong with the enlargement(s) provided in the longer, parallel side(s) of the aperture. Obviously it is desirable for there to be some merging between the aperture and its enlarged, lead-in portion, and conveniently this may be effected by an interconnecting, inclined, or radiussed face. Additionally, an inner end of the aperture may be provided with grooves to achieve an enhanced latching effect on a shank of a pick insertable into the aperture.

The invention will now be further described, by way of example, with reference to the accompanying drawings', in which: Figure 1 is a plan view of a pick box in accordance with the invention; Figure 2 is a section on the line 1I--II of Figure 1;and Figure 3 is a section on the line Ill-Ill of Figure 1.

In the drawings, a pick box 1 comprises a body member 2 having an inner end 3 adapted to be seated on or in, and welded to, a rotary member (not shown) such as a spiral vane rotary cutting drum or a cutting head of an underground roadway driving machine, and an outer end 4.

An oblong aperture 5 having longer parallel sides 6 shorter parallel sides 7 extends in length through the body member 2 from an open mouth 8 at the end 4 to the end 3, the aperture being formed by drilling an initial hole 9, visible in part in all the Figures, and thereafter broaching to oblong section. The aperture 5 has an enlarged lead-in portion 10 extending inwardly from the open mouth 8, provided in both longer aperture sidewalls 6, over part of the length of the aperture 5. The lead-in portion 10 is formed by counterboring the initial hole 9 as far as an inclined face 11 which interconnects the initial hole 9 and the lead-in portion 10. Additionally, an inner end 12 of the aperture 5 may be provided with grooves 13 to achieve an enhanced latching effect on a shank (not shown) of a pick insertable into the aperture 5, the body member 2 also being provided at its inner end 3 with a machined slot 14 for the insertion of a drift to remove a worn or damaged pick from the box 1, in a conventional manner.

Claims

CLAIMS:

1. A pick box having an aperture to receive the shank of a replaceable mineral cutting pick comprising a body member, a generally rectangular aperture provided in the body member, extending inwardly from an open mouth at one end of the body member and serving to receive a pick shank of generally rectangular cross-section, the aperture having an enlarged, lead-in portion hhat extends inwardly from the open mouth, is provided in at least one side of the aperture and extends over part of the length of the aperture.

2. A pIck box as claimed in Claim 1, wherein an enlarged, lead-in portion is provided in one sidewall only of the aperture.

3. A pick box as claimed in Claim 1, wherein an enlarged lead-in portion is provided in each of two opposite sidewalls of the aperture.

4. A pick box as claimed in any preceding Claim, wherein the aperture is formed in the body member by drilling a hole through the body member in the direction in which the aperture is to extend, with the hole subsequently expanded from this circular section to the required rectangular section by broaching and the enlargement is produced by counterboring to provide a lead-in portion of slightly greater diameter than the drilled hole, and capable therefore of accommodating a shank with a resilient latching member projecting to one side, or to two opposite sides of the shank.

5. A pick box as claimed in any preceding Claim, wherein the aperture is oblong with the enlargement(s) provided in the longer, parallel side(s) of the aperture.

6. A pick box as claimed in any preceding Claim, wherein an interconnecting, inclined, or radiussed face is provided between the aperture and its enlarged, lead-in portion.

7. A pick box as claimed in any preceding Claim, wherein an inner end of the aperture is provided with grooves to achieve an enhanced pick-latching effect.

8. A pick box having an aperture to receive the shank of a replaceable mineral cutting pick, substantially as hereinbefore described with reference to the accompanying drawings.