GB2180180A

GB2180180A - Collar splitters for lock bolt fastening systems

Info

Publication number: GB2180180A
Application number: GB08522668A
Authority: GB
Inventors: Joseph Lockey
Original assignee: Coal Industry Patents Ltd
Current assignee: Coal Industry Patents Ltd
Priority date: 1985-09-13
Filing date: 1985-09-13
Publication date: 1987-03-25
Also published as: GB2180180B; GB8522668D0

Abstract

The collar splitter comprises a body (1) having a partly tapered passage (2,3), a draw rod component (5,10,11) slidable within the passage, and a cutter blade arrangement (13,14,15,18) pivotally mounted on the draw rod component. A toggle link arrangement (15,18) ensures that when the collar splitter is activated to split the relatively soft locking collar (26) the cutter blades (13,14) do not contact the relatively hard lock bolt (27). <IMAGE>

Description

SPECIFICATION Collar splitters for lock bolt fastening systems This invention relates to improvements in collar splitters for lock bolt fastening systems, the fastening systems comprising a lock bolt having a head and a shaft provided with a number of annular grooves in place ofthe conventional screwthread. Instead of a conventional nut having a screwthread a locking collar is provided which, in use, is slid along the lock bolt shaft into a tightly retaining position and is then crushed on to the annulargroovesto rigidly secure the lock bolt fastening system. When it is desired to disconnectthefastening system it is necessary to splitthelocking collarwhichtherebyisreleasedfrom the bolt.

Various methods have been used to remove the locking collar including manually held chisels and power activated chisels including a pair of opposed cutting blades for engaging the collar. Unfortunately, in many installations using lock boltfastening systems the prior available power activated chisels are prevented from locating on the nuts because of adjacent items of equipment mounted in the vicinityofthe nuts. Previously, in such installations it has been necessary to turn to the time consuming and arduoustasks of using manually held chisels and hammers to release the collar.

An object of the present invention is to provide an improved collarsplitterfor lock bolt fastening systems which tends to overcome or reduce the above mentioned problem.

Accordingtothe present invention acollarsplitter for disconnecting a lock bolt fastening system having a lock bolt and locking collar comprises a bodydefining passage means, a rod componentslidablewithin the passage means, and a cutter blade arrangement pivotally mounted on the rod component, the body and the rod component being adapted for engagement by a powered tool such that in use when the tool is activated the rod componenttogetherwith at least a portion of the cutter blade arrangement slide relative to the passage means, the cutter tool arrangement co-operating with the passage means such that in use when the cutter blade arrangement is en gaged on the locking collar and the tool is activated, the cutter blade arrangement is urged to close to split the locking collarto disconnect the lock boltfastening system.

Preferably, at least a portion ofthe passage means is tapered. Advantageously, the cutter blade arrangement comprises a plurality of cutter blade components pivotally mounted on the rod component.

Preferably, each cutter blade component comprises a cutter blade and a toggle link pivotallyconnecting the associated blade to the rod component.

Conveniently, the rod component is a draw rod for urging the cutter blade arrangementfurther into the tapered passage means.

Preferably, the body defines groove means for guidably receiving portions of the cutter blade arrangement.

Bywayofexample,oneembodimentofthepre- sent invention will be described with reference to the accompanying drawings, in which: Figure 1 is a side elevation, partly in section, of a collar splitter constructed according to the present invention and shown in an operational position; and Figure2 is an incomplete cross sectional view taken along line Il-Il of Figure 1.

In the drawings the locking collar splitter is shown mounted on a hydraulically actuated powered tool 6 and engaging a locking collar 26 fixedly mounted on a lock bolt 27 of a lock bolt fastening system fixedly securing equipment 28.

The drawings showthe locking collar splitterto comprise a hollow body 1 defining a through stepped passage 2 a portion 3 of which, as seen in Figure 1 is tapered outwardly towards one end. The end 4 of the passage opposite to said one end substantially is parallel and defines a slidewayfora draw rod component 5 as will be explained later in the specification. The end of the body adjacent to the parallel portion 4 of the passage 2 is provided with means (notshown)forfixedly attaching the body to a nose portion ofthe hydraulically powered tool 6. The outwardly tapered portion 3 ofthe passage 2 is prov ided with two opposed g rooves 7 and 8 for guidably supporting portions of a cutter blade arrangement 9.

The aforementioned draw rod component 5 is slidably mounted within the passage 2 and is slidably supported by the parallel portion 4 of the passage.

The draw rod component 5 comprises adaptor means 6 for drivable engagement by a working portion of the tool which when the tool is activated draws the draw rod component 5 further into thetool body relatively to the nose portion. Thus when the tool is activated the draw rod component is effectively slid along the passage 2 in a direction tow ards the tool 6. The working portion ofthetool is not shown in the drawings.

The end of the pull rod component 5 remote from the tool 6 is provided with an enlarged head 10 having an outwardly directed flange 11 on to which is pivotally mounted the aforementioned cutter blade arrangement9,the arrangement comprising two opposed cutter blade components each pivotally con nectedtotheflange 11 ofthedraw rod component head 10. Each cutter blade component comprises a cutter blade 13 having a radiallyinwardlydirected cutting edge 14 and a toggle linkarrangement 15 pivotally engaged on opposite sides oftheflange 11 and of the associated blade 13.Pivot pins 18 pivotally retain the toggle link arrangements to theflange and blades. The provision of the toggle link arrangement enables that during cutting the associated cutting edge 1 4 of each blade 1 3 to be maintained substanti- ally parallel to the passage's longitudinal axis thereby enabling a substantially uniform cutting action to be maintained across thefull width of the locking collar 26. This is important, as in use, such a constructionenablesthebladestocutthroughthe relatively soft collar sufficiently to split the collar before any part of the blades contacts the relatively hard lock bolt 27. Thus, damage to the blades is avoided and wearofthe cutting edge reduced to a minimum.

In use, the cutter blades of the cutter blade arrangement are located on opposite sides of the locking collar 26 to be split (as shown in the drawings). The relatively long body enabling the collarsplitterto be threaded past any adjacent items of equipment. The hydraulically powered tool 6 then is activated to draw the draw rod componenttowards the tool thereby drawing the cutter blade arrangement along the passage 2further into the body 1 The effect of this sliding movement is to urge the cutter blades along the guide grooves and further into the tapered portion of the passage thereby urging the cutting edges to close and cut through the locking collar 26. Upon sufficient closing ofthe cutter blades the relatively soft collar splits to release the collarfrom the lock bolt to disconnectthe lock bolt fastening system.

It will be appreciated that the present invention provides a simple, effective and reliable locking collarsplitterwhich is able to engage locking collars, installed in the vicinity of other items of equipment.

The sides ofthe body are cut away to assist collar engagement in restricted zones and the leading edges of the body are chamfered to assist in locating the collar.

In modified embodiments the two cutter blades are not diametrically opposed but arranged to cut along a chord across the locking collar.

Claims

1. Acollarsplitterfordisconnecting a lock bolt fastening system having a lock bolt and collar, comprising a body defining passage means, a rod com ponentslidablewithinthe passage means, andacut- ter blade arrangement pivotally mounted on the rod component, the body and the rod component being adapted for engagement by a powered tool such that in use when the tool is activated the rod component together with at least a portion ofthe cutter blade arrangement slide relative to the passage means, the cutter tool arrangement co-operating with the passage means such that in use when the cutter blade arrangement is engaged on the locking collar and the tool is activated, the cutter blade arrangement is urged to close to splitthe locking collarto disconnect the lock boltfastening system.

2. Acollarsplitteras claimed in claim 1, in which at least a portion ofthe passage means is tapered.

3. Acollarsplitteras claimed in claim 1 or2, in which the cutter blade arrangement comprises a plurality of cutter blade components pivotally mounted on the rod component.

4. A collar splitter as claimed in claim 3, in which each cutter blade component comprises a cutter blade and a toggle link pivotally connecting the associated blade to the rod component.

5. Acollarsplitteras claimed in any one ofthe preceding claims, in which the rod component is a draw rod for urging the cutter blade arrangement further into the tapered passage means.

6. Acollarsplitterasclaimedinanyoneofthe preceding claims, in which the body defines groove means for guidably receiving portions of the cutter blade arrangement.

7. Acollarsplitterfordisconnecting a lock bolt fastening system substantially as described herein and substantially as shown in the accompanying drawings.