GB2154922A

GB2154922A - Improvements relating to collar splitters

Info

Publication number: GB2154922A
Application number: GB08405225A
Authority: GB
Inventors: Joseph Lockey
Original assignee: Coal Industry Patents Ltd
Current assignee: Coal Industry Patents Ltd
Priority date: 1984-02-29
Filing date: 1984-02-29
Publication date: 1985-09-18
Also published as: GB2154922B; GB8405225D0

Abstract

An improved collar splitter comprises a draw bolt (1), a pair of cutter blades (3 and 4) and a bias collar (2). The cutter blades (3 and 4) sever the collar, e.g. a collet (11) crushed onto a huck bolt (12), when the bias collar (2) forced along the draw bolt (1) onto the cutter blades (3 and 4). <IMAGE>

Description

SPECIFICATION Improvements relating to collar splitters This invention relates to improvements in collar splitters. In particular this invention relates to improvements in splitters for huck bolt collets as used, for example, in underground mining operations.

In many fields of engineering fastenings of the nut and bolt type are used, the nut effectively forming a collar at one end of the bolt. One derivative of the conventional nut and bolt is the huck bolt and collet. This type of fastening incorporates a "bolt" having a head and shaft with a series of annular grooves in place of the conventional thread onto which grooves is crushed the collet after the huck bolt has been positioned through the work pieces to be joined. Again the collet effectively forms a collar at the end of the huck bolt. When it is necessary to dismantle the equipment the nut and bolt or collet and huck bolt must be undone viz the "collar" must be removed from the bolt.

In modern underground mining a lot of expensive equipment is used. Due to the restricted access within mine workings most equipment is transported to, for example, a face in pieces and bolted together in situ.

When the mineral reserve of the face is exhausted it is preferable to dismantle and recover as much of the equipment as possible.

Conventional nuts and bolts are used but suffer the disadvantage of loosening due to vibration etc. during use. Huck bolts and collets offer the advantage over conventional nuts and bolts that they cannot loosen or come undone in service. They do however pose a problem when the equipment in which they are used is being dismantled. Various methods may be used to remove the collet, including manual or powered chisels. These methods have proved timeconsuming and far from ideal as positioning of a single chisel edge on the round contour of the collet is difficult and also access to the collet may be awkward, for example, in certain positions within armoured face conveyor line pans. It has therefore been necessary to devise some means of simplifying the removal of collets from huck bolts.It is therefore an object of the present invention to provide an improved collar splitter that will overcome in part the disadvantages of existing means for splitting collars.

Accordingly a primary aspect of the present invention provides a collar splitter comprising a draw bolt, a plurality of cutter blades pivotally mounted at one end of the draw bolt arranged to swing radially from the centre line of the draw bolt, and a bias collar adapted to slide along the draw bolt and bias the cutter blades towards the centre line of the draw bolt.

Preferably the bias collar may have a number of axial grooves around its inside diameter adapted to locate on the back of each cutter blade.

There may be two cutter blades diametrically opposite one another.

The draw bolt may advantageously be adapted to fit an existing huck bolt assembly tool.

Preferably the cutter blades may be adapted so as to close only to the diameter of a selected size huck bolt.

A second aspect of the present invention provides a method for splitting collars off bolts, comprising positioning a collar splitter, according to a first aspect of the present invention, about a collar and operating the collar splitter so as to split the collar diametrally or chordally.

One embodiment of a collar splitter according to the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a side view of a collar splitter according to the invention; and Figure 2 is a section view of the collar splitter taken on line A-A of Fig. 1.

Referring now to the drawings, a collar splitter according to the invention is based on a draw bolt 1, one end of which is adapted to fit a conventional powered huck bolt assembly tool (not shown) and the other end of which has pivotally mounted thereof a pair of cutter blades 3 and 4. The cutter blades 3 and 4 are free to swing radially from the end of the draw bolt 1 and, being diametrically opposite one another, actually swing along a common diameter of the draw bolt 1. A bias collar 2 has a first internal diameter 5, which allows a smooth sliding fit on the draw bolt 1, and a second, larger internal diameter 6. Within the second internal diameter 6 are a pair of axial grooves 7 and 8 which are diametrically opposite one another and which are adapted to fit the outside edges of the two cutter blades 3 and 4.The cutter blades 3 and 4 have cutting edges 9 and 10 which are adapted, when sitting diametrically across a huck bolt 12, to sit substantially parallel to the sides of the huck bolt 12 so that in use, a collet 11 is completely severed across its entire section without the cutting edges 9 and 10 damaging the huck bolt 12 to any material extent.

In use the collar splitter draw bolt 1 is inserted into a powered huck bolt assembly tool. The cutter blades 3 and 4 are opened and positioned, preferably diametrically, across the collet 11 sitting on the end of the huck bolt 12. The powered assembly tool is operated at which point the bias collar 2 is forced along the draw bolt 1 (right to left on Fig. 1) which forces cutter blades 3 and 4 together which severs the collet 11 in two places preferably at 1 80' to each other. The collet 11 is thus split by the pincer like action of the cutter blades 3 and 4 and falls off leaving the huck bolt 12 free to be withdrawn. It should be noted that the collar splitter may be positioned on the collet to effect a diametral or chordal cutting action.

As can be seen the collar splitter according to the invention is simple and therefore reliable. It may be used with existing powered huck bolt assembly tools which may greatly reduce the need for additional specialist power tools and its operation is so close to that of assembly that a trained huck bolt assembler may easily use the collar splitter of the invention. It is expected to find considerable application in mining installations which use huck bolt and collet assembly but may just as well be used as a conventional nut splitter as the tool may easily be adapted to suit a variety of "collar" and bolt type fastenings.

Claims

1. A collar splitter, comprising a draw bolt, a plurality of cutter blades pivotally mounted at one end of the draw bolt arranged to swing radially from the centre line of the draw bolt, and a bias collar adapted to slide along the draw bolt and bias the cutter blades towards the centre line of the draw bolt.

2. A collar splitter according to claim 1, wherein the bias collar has a number of axial grooves around its inside diameter adapted to locate on the back of each cutter blade.

3. A collar splitter according to claim 1 or 2, wherein there are two cutter blades diametrically opposite one another.

4. A collar splitter according to any one of the preceding claims, wherein the draw bolt is adapted to fit an existing huck bolt assembly tool.

5. A collar splitter according to any one of the preceding claims, wherein the cutter blades are adapted so as to close only to the diameter of a selected size huck bolt.

6. A collar splitter substantially as hereinbefore described with reference to the accompanying drawings.

7. A method for splitting collars off bolts, comprising positioning a collar splitter, according to a first aspect of the present invention, about a collar and operating the collar splitter so as to split the collar diametrally or chordally.