GB2164679A

GB2164679A - Tool retaining devices

Info

Publication number: GB2164679A
Application number: GB08424015A
Authority: GB
Inventors: Ian Gregory Wiley
Original assignee: SPENCER TODWICK Ltd
Current assignee: SPENCER TODWICK Ltd
Priority date: 1984-09-21
Filing date: 1984-09-21
Publication date: 1986-03-26
Also published as: GB2164679B; GB8424015D0

Abstract

A tool retaining device for releasably retaining a tool shank 12 of a mineral cutting tool, in a socket 11 in a tool holder 10, and comprising a rigid member 16 having a portion to engage in a recess in the tool shank 12 and a further portion engageable in an opening in the holder 10, communicating with the socket therein, and a resilient member 17 having a surface 21 engageable with a complementary surface 18 on the rigid member 16, said surfaces being tapered with respect to the lengths of these members so that a wedging action is achieved between the members 16, 17 to secure the tool 12 in the tool holder 10. <IMAGE>

Description

SPECIFICATION Tool retaining devices This invention relates to tool retaining devices, primarily, though not exclusively, for mineral cutting or mining picks, whereby they are releasably retained in holders which may be attached to or form part of a chain, drum or other cutter assembly.

In the type of tool and tool holder combination with which the invention in concerned, the holder has a socket into which a shank of the tool fits, there being also a bore or other opening extending generally transversely with respect to the socket and entering the interior of the socket for receiving a tool retaining member which is releasably engaged with the tool shank to secure it in the tool holder. A pin or other rigid part may serve as the tool retaining member and this may be resiliently mounted.

A number of systems have been devised to hold the tool in the holder and many of them rely upon a resilient element to secure the tool retaining mem ber in place. The resilient element may conveniently be made from rubber or equivalent elastic material.

This is preferable to springs which could become choked with mineral dust and thus resist removal when the tool is to be extracted for maintenance or replacement. However several of the known systems which use this arrangement are complicated and some are not reliable in use. Reliability of the retaining device is obviously necessary since tools may otherwise become loose. Build up of dust or dirt must not unduly impair the reliability nor the ability to extract the tool when needed. One example, which is however effective in certain operating conditions is described and claimed in Patent No.

2,032,980.

It is the object of this invention to provide a tool retaining device which is simple but reliable in operation as well as enabling tool removal to be simply carried out. According to the invention there is provided a tool retaining device for releasably retaining a tool shank in a socket in a tool holder, comprising a rigid member having a portion to engage in a recess in the tool shank and a further portion engageable in an opening in the holder communicating with the socket, and a resilient member engageable in the opening in the holder, having a surface engageable with a complementary surface on the rigid member, said surfaces on the resilient member and the rigid member being complementarily tapered, with respect to the lengths of those members, so that in use a wedging action is achieved between the rigid member and the resilient member, by movement of the resilient member in one direction of its length.

In accordance with a further aspect of the invention there is provided a tool and tool holder combination wherein the tool has a shank and the tool holder has a socket to receive the shank of the tool, the holder having an opening extending laterally of the direction of entry of the tool shank into the socket, said opening communicating with the interior of the socket, the tool shank having a recess which, when the tool shank is within the socket, is in communication with the opening in the tool holder, and wherein the tool shank is arranged to be secured in the tool holder by a tool retaining device compris ing, in combination a rigid member having a portion engageable in the recess of the tool shank and a further portion engageable in the opening in the tool holder and a resilient member movable in the said opening lengthwise thereof, the resilient member and the rigid member having complementary interengageable surfaces which are tapered relatively to the lengths of the said resilient and rigid members and the arrangement being such that movement of the resilient member relatively to the rigid member tends to move the rigid member towards and into contact with the tool shank or away therefrom to lock or release the tool shank relatively to the tool holder.

Preferably the complementary interengageable surfaces of the resilient member and the rigid member are serrated or otherwise formed to increase frictional resistance to relative movement between those members, and preferably, in particular, in one direction.

Conveniently the portion of the rigid member engageable in the recess in the tool shank is shaped to engage the sides of the socket in the tool holder, to resist movement of the rigid member lengthwise thereof.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a cross-sectional view of a tool and tool holder combination constructed in accordance with the invention, and Figure 2 is a side view of the tool holder of Figure 1.

The drawings show a tool holder 10 in the form of a generally rectangular body having a rectangular socket 11 for reception of the rectangular shank 12 of a tool which is typically a mineral pickthough other tools may be held by the device described.

As shown in Figure 2, the socket extends right through the tool holder and the tool shank extends also substantially the full depth of the tool holder.

The tool head is indicated generally at 13 in Figure 2.

To retain the tool shank in the socket in the holder, there is a retaining device which occupies an opening 14 which extends right through the tool holder body in a direction transversely to the direction of the length of the socket 7. The opening 14 as seen in Figure 2 is of key-hole shape and communicates with the socket. At the position corresponding with that at which the opening breaks into the socket, the tool shank has a V-shaped slot 15 which extends transversely with respect to the length of the tool shank 11.

Occupying the opening 14 in the tool holder body 10 is the retaining device which comprises a rigid member 16 and a resilient member 17. The rigid member 16 is of generally wedge-shape from end to end and has a serrated surface 18. Projecting from the opposite surface is a tongue-form extension 19 having a length corresponding with that of the tool shank 12. As seen in Figure 1 the extension 19 projects into the V-shaped slot 15 in the shank and has a complementary V-form as seen in Figure 2. At either side of the extension 19 the rigid member 16 has semi-cylindrical surface portions as seen in Figure 2 at 20.Figure 2 also shows that the opening 14is off-set from the tool shank slot 15 by a small amount so that the rigid member 16 tends to bear on one surface of the slot 15 in the tool shank, thus tending to hold it securely in the tool holder. The heel of the head 13 of the tool engages the end surface of the tool holder to iimit inward movement ofthetool shank with respect to the tool holder socket.

The resilient member 17 of the tool retaining device is also a wedge-shaped member having a truncated triangular cross-sectional form as seen in Figure 2. One surface of the resilient member 17 is serrated at 21 to correspond with the serrations of the surface 18 of the rigid member 16. The serrations of both members are of dog-tooth form so that when engaged the rigid and resilient members are prevented from moving relatively to one another in the directions of their lengths. Movement in one direction is easier than the other because of the dog-tooth form of the serrations and it is therefore relatively easy to push the resilient member in the direction of the arrow 22 in Figure 1. Pushing in of the resilient member tends to apply a force to the rigid member 16 in the direction of the arrow 23 in Figure 1, thus forcing this against the shank of the tool to hold it firmly in place.

Fitting of the tool into the tool holder and securely fixing it in place is therefore accomplished by inserting the rigid member 16 to engage the extension 19 into the slot 15 in the tool shank 12. The resilient member 17 is now entered from the opposite side of the tool holder opening 14 and is driven in as indicated by the arrow 22 until a tight fit is achieved.

To remove the tool from the tool holder the resilient member 17 is driven out in the direction opposite to the arrow 22 and this will usually result in shearing of the serrations on the resilient member. Refitting will therefore require the use of a new resilient member.

Claims

1. Atool retaining device for releasably retaining a tool shank in a socket in a tool holder, comprising a rigid member having a portion to engage in a recess in the tool shank and a further portion engageable in an opening in the holder communicating with the socket, and a resilient member engageable in the opening in the holder, having a surface engageable with a complementary surface on the rigid member, said surfaces on the resilient member and the rigid member being complementarily tapered, with respecs to the lengths of those members, so that in use a wedging action is achieved between the rigid member and the resilient member, by movement of the resilient member in one direction of its length.

2. Atool retaining device as claimed in claim 1 in which the complementary interengageable surfaces of the resilient member and the rigid member are serrated or otherwise formed to increase frictional resistance to relative movement between those members.

3. Atool retaining device as claimed in claim 2 wherein the complementary interengageable surfaces of the resilient member and the rigid member are shaped to increase frictional resistance to movement, particularly in one direction.

4. A tool retaining device as claimed in any one of the preceding claims in which the portion of the rigid member engageable in the recess in the tool shank is shaped to engage the sides of the socket in the holder, to resist movement of the rigid member lengthwise thereof.

5. A tool and tool holder combination wherein the tool has a shank and the tool holder has a socket to receive the shank of the tool, the holder having an opening extending laterally of the direction of entry of the tool shank into the socket, said opening communicating with the interior of the socket, the tool shank having a recess which, when the tool shank is within the socket, is in communication with the opening in the tool holder, and wherein the tool shank is arranged to be secured in the tool holder by a tool retaining device comprising, in combination, a rigid member having a portion engageable in the recess of the tool shank and a further portion engageable in the opening in the tool holder and a resilient member movable in the said opening lengthwise thereof, the resilient member and the rigid member having complementary interengageable surfaces which are tapered relatively to the lengths of the said resilient and rigid members and the arrangement being such that movement of the resilient member relatively to the rigid member tends to move the rigid member towards and into contact with the tool shank or away therefrom to lock, or release the tool shank relatively to the tool holder.

6. Atool retaining device substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

7. Atool and tool holdercombination substantially as hereinbefore described with reference to and as shown in the accompanying drawings.