GB2111098A

GB2111098A - Improvements in or relating to pick retaining devices

Info

Publication number: GB2111098A
Application number: GB08135467A
Authority: GB
Inventors: Henry Mcgaw Brown; Sidney Ernest Proctor
Original assignee: Anderson Strathclyde Ltd
Current assignee: Anderson Strathclyde Ltd
Priority date: 1980-12-04
Filing date: 1981-11-25
Publication date: 1983-06-29
Also published as: DE3147600A1; BR8107865A; FR2495685A1; AU7778781A

Abstract

A shanked tool (particularly a mineral mining tool) is received in the socket 3 of a holder 4 provided with a cam or eccentric 5 which can be turned so that a portion of its surface engages the tool shank to retain the shank in the socket. The cam or eccentric may be disposed wholly within the socket and may extend across the socket from side to side. The rotational axis of the cam or eccentric may be inclined at an acute angle to the socket axis normal. Where the socket is rectangular, the rotational axis of the cam or eccentric may lie at an acute angle to the side of the socket from which the cam or eccentric is arranged to project. The cam or eccentric may comprise threaded portions engaging correspondingly threaded portions of the holder. <IMAGE>

Description

SPECIFICATION Improvements in or relating to pick retaining devices The invention relates to a device for retaining a shanked tool in a socketed holder and more particularly, but not exclusively, to a device for retaining a shanked mineral cutter pick in a pick box.

According to the invention there is provided the combination of a shanked tool and a holder having a socket for receiving the tool shank to support tool during use, wherein the holder is provided with a cam or eccentric which can be turned so that a portion of its surface engages the tool shank to retain the shank in the socket.

The portion of the surface of the cam or eccentric which engages the tool shank is preferably curved. The arrangement may be such that rotation of the cam or eccentric causes a part thereof to project into the socket. The rotational axis of the cam or eccentric may be arranged substantially normal to the axis of the socket, or may be inclined at an acute angle to the socket axis normal. Where the socket is rectangular the rotational axis of the cam or eccentric may lie at an acute angle to the side of the socket from which the cam or eccentric is arranged to project.

The cam or eccentric may comprise threaded portions engaging correspondingly threaded portions of the holder, preferably one on each side of the socket.

Preferably means is provided for limiting rotation of the cam or eccentric in the holder.

The means may comprise a pin projecting generally normally from the cam or eccentric and engageable with abutments on the holder.

Preferably means is provided for preventing or reducing risk of unintentional slackening of the cam or eccentric during use. Where the cam or eccentric is screw-threaded into the holder, frictional inserts may be provided between the mating screw threads to achieve this purpose. Alternatively where the means for limiting rotation of the cam or eccentric is a pin projecting therefrom, the pin may be arranged to engage a face cam which biases the pin to rotate the cam or eccentric into engagement with the tool shank. The face cam may include a pair of oppositely sloped portions whereby, according to which portion is engaged by the pin, the cam or eccentric is either urged into the operative or non-operative position.

From another aspect the invention provides a holder for use in the combination described above, the holder having a socket for receiving the shank of a tool to support the tool during use, and tool retaining means comprising a cam or eccentric rotatable to cause a portion of its surface to engage the tool shank.

From yet another aspect the invention is a tool for use in the combination described above, the tool having a shank arranged for reception in a socket in a holder and the shank being formed with a recess the wall of which is adapted to be engaged by a cam or eccentric in the holder to secure the tool in the socket. The recess in the tool shank is preferably a groove extending generally normal to the axis of the shank. Where the cam or eccentric is inclined the recess is preferably correspondingly inclined at an acute angle to the normal to the axis of the tool shank.

From another aspect there is provided the combination of a shanked tool and a holder having a socket for receiving the tool shank to support the tool during use, wherein the holder is provided with a cam or eccentric disposed within the socket and which can be turned so that a portion of its surface engages a tool shank in the socket to retain the shank in the socket.

The cam or eccentric may extend across the socket from side to side or alternatively it may project only part-way across the socket. The tool shank is preferably formed with a slot or recess extending completely through the shank or partly through the shank as necessitated by the amount by which the cam or eccentric projects into the slot or recess to allow the tool shank to be fully inserted into the socket before the cam or eccentric is rotated to engage and retain the tool shank.

The shank is preferably formed with an abutment surface for engagement by the cam or eccentric, which abutment surface is preferably inclined with respect to the axis of the tool shank.

The slot or recess in the tool shank is preferably terminated with a further abutment face which may if desired be normal to the axis of the tool shank and which is arranged to be engaged by the cam or eccentric when it is turned in a direction to release the tool, to tend to lift the tool from the fully inserted position in the socket.

From another aspect the invention provides a holder for use in the combination described above, the holder having a socket for receiving the shank of the tool to support the tool during use, and tool retaining means comprising a cam or eccentric disposed in the socket and which is rotatable to cause a portion of its surface to engage the tool shank to retain it in the socket. The cam or eccentric may extend across the socket from side to side or alternatively it may project only part-way across the socket.

From yet another aspect the invention is a tool for use in the combination described above, the tool having a shank arranged for reception in a socket in a holder and the shank being formed with a recess or slot extending from its free end axially of the socket and having at its inner end an inclined abutment surface for engagement by the cam or eccentric. Preferably the slot or recess is terminated with a further abutment face which may be disposed normal to the axis of the tool shank and which is arranged to be engaged by the cam or eccentric when it is rotated in a direction to release the tool to tend to lift the tool from its fully inserted position in the socket. The recess or slot is preferably disposed substantially centrally of the width of the tool shank.Where, as is conventional, the tool shank is rectangular in cross-section the recess or slot preferably emerges from the major face or faces of the tool shank.

The invention is diagrammatically illustrated by way of example in the accompanying drawings in which: Figure 1 is a side view in cross section of a first embodiment according to the invention; Figure 2 is a front view of the eccentric used in the embodiment of Fig. 1; Figure 3 is a cross section on the line A-A of Fig. 2; Figure 4 is a side view of the eccentric shown in Fig. 2; Figure 5 is a side view of a holder shown in the embodiment of Fig. 1; Figure 6 is an end view of a holder similar to that shown in Fig. 5 but showing a second embodiment of the invention; Figure 7 is a side view of a tool shank for use in the embodiment of Fig. 6; Figure 8 is an end view of the tool shank shown in Fig. 7; Figure 9 is a plan view of a holder similar to that of Figs. 5 and 6 but showing a third embodiment;; Figure 10 is a side view of a holder similar to that of Fig. 1 but showing a fourth embodiment; Figure 11 is an end view partly sectioned of the holder of Fig. 10; Figure 12 is a view similar to that of Fig. 2 but showing modified form of eccentric; Figure 13 is a side view of a holder showing means for rotating the cam or eccentric and means for limiting the rotation; Figure 14 is an end view of the holder of Fig. 13; Figure 15 is a plan view of the holder of Figs. 1 3 and 14; Figure 16 is a sectional side view of a holder showing another embodiment; Figure 1 7 is a partly sectioned plan view of the holder of Fig. 16; Figure 18 is a side view of the holder of Figs. 16 and 17; Figures 19 to 22 show details of the tool retaining means of the embodiment of Figs.

16 to 18; Figures 23 and 24 show details of the device used for operating the tool retaining means of the embodiment of Figs. 1 6 to 18; Figure 25 is a side view of a further embodiment of holder which is generally similar to that of Figs. 1 6 to 18; Figure 26 is an end view of the holder of Fig. 25; Figure 27 is a sectional side elevation of a mineral cutter pick partly inserted in a pick box; Figure 28 is a view corresponding to that of Fig. 27 but showing the pick fully inserted into the pick box and fastened in place; Figure 29 is a plan view of a cam or eccentric latching device; Figure 30 is an end elevation of the latching device of Fig. 29; Figure 31 is a side view of the pick shank as shown in Figs. 27 and 28; Figure 32 is a side view of the pick box; and Figure 33 is an end view of the pick box of Fig. 32.

In the drawings referring more particularly to Figs. 1 to 5 there is shown a mineral cutter pick 1 having a shank 2 which is retained in a socket 3 in a holder or pick box 4. The shank of the pick is retained in the holder by means of an eccentric mechanism 5 mounted in a bore 35 in the holder and which projects into the socket 3 so as to engage in a recess 6 in the shank 2 of the pick. As can be seen in Figs. 2 to 4 of the drawings, the eccentric mechanism 5 is generally cylindrical in form and comprises a pair of threaded portions 7 disposed on either side of a central cylindrical portion 8 which is the portion which projects into the socket to engage the pick shank, the mechanism being terminated at each end with a square section which can be engaged by a suitable spanner or other tool to rotate the mechanism.It will be seen from Fig. 3 of the drawings that the central cylindrical section 8 is axially offset with respect to the threaded section 7. The eccentric mechanism is arranged in the holder 4 so that the threaded portions 7 engage correspondingly internally threaded portions 10 of the bore 35 disposed one on either side of the socket 3 so that rotation of the mechanism causes the central portion 8 to protrude into the socket 3.

The arrangement shown in Figs. 6 to 9 of the drawings is generally similar to that described above except that, as shown in Fig. 6 of the drawings, the axis of the bore 35 in the holder 4 for receiving the eccentric mechanism 5 is inclined with respect to the normal to the axis of the socket 3, and, as shown in Fig. 9 of the drawings, the axis of the bore 35 is arranged to lie at a small angle with respect to the side of the rectangular socket 3 from which the mechanism projects into the socket.

Figs. 6 and 7 of the drawings show how the recess 6 in the tool shank 2 is correspondingly inclined.

The purpose of inclining or twisting the bore 35 for receiving the eccentric mechanism is to enhance the latching effect, on the basis that the axial load thereby imposed on the eccentric mechanism will force the threads 7 more firmly into contact with the correspondingly threaded portions 10 of the bore 35 so as to avoid accidental loosening of the device during use.

In the arrangements described above, the eccentric mechanism is screwed into the holder to a position where its central portion 8 coincides with the socket 3 in the holder. The pick shank is inserted into the holder when the portion 8 of the eccentric is in its rearward position, that is to say when it does not project into the socket. When the mechanism 5 is subsequently rotated through approximately 120 the portion 8 will contact the lower edge of the recess 6 in the pick shank and will exert a force on the pick shank tending to force the shank further into the socket. Entry of the shank into the socket is, of course, limited by conventional abutments on the pick.

Figs. 10 and 11 illustrate an embodiment generally similar to those described above except that the threaded portions of the eccentric mechanism are replaced by plain discs 11 which are rotatable in recesses 1 2 in the sides of the holder 4. The parts 8, 9 and 11 which together make up the eccentric mechanism are secured together so that they rotate together and as in the previous embodiment the axis of the central part 8 is offset from the axis of the discs 11.

As shown in Fig. 1 2 of the drawings, the threaded portion 7 of the eccentric mechanism 5 of Fig. 2 may be provided with hard resilient inserts 1 3 e.g. of neoprene to resist unintended rotation of the mechanism in use.

Referring to Figs. 1 3 to 1 5 of the drawings there is shown an arrangement of the kind generally described above and comprising means for limiting the angle through which the eccentric mechanism can be rotated. This is achieved by replacing the flat portions 9 of the eccentric mechanism 5 of Fig. 2 with generally wedge shaped terminal portions 1 4 which can be engaged in one position only by a wrench 1 5 having an aperture shaped to receive a terminal portion to rotate the eccentric mechanism.Rotation of the eccentric mechanism is limited by means or pegs 1 6 which are received frictionally in bores in the holder 4, which project from the sides of the holder and which are arranged to engage the wrench after rotation through an angle of 120 . If however it becomes necessary to remove the eccentric mechanism, it is necessary only to knock the pegs 1 6 flush with the face of the holder whereupon the wrench can be rotated freely.

The arrangement described in Figs. 1 6 to 22 is generally similar to those described above except that the eccentric mechanism comprises a D-section pin 1 7 eccentrically mounted in a correspondingly shaped cavity in a cylindrical sleeve 1 8 which is cut away at 21 (see Fig. 21) to expose a portion of the pin 1 7 which corresponds to the central portion 8 of the eccentric mechanism of Fig. 2. The sleeve 1 8 is mounted in a cylindrical bore 35 in the holder which intersects the socket 3.

Near each end the pin 1 7 carries spring pins 1 9 disposed in cavities 22 therein and which project from the pin 1 7 to prevent axial movement of the eccentric mechanism in use and also to limit rotational movement of the eccentric mechanism. For this purpose the pins 1 9 are disposed in recesses 20 in the holder 4 and rotation of the eccentric mechanism is limited by abutment of the pins with the extremities of the cavity as can best be seen in Fig. 18. Figs. 23 and 24 illustrate a wrench 1 5 which may be engaged with the end of the D-shaped pin 1 7 of the eccentric mechanism of Figs. 1 6 to 22 to rotate the mechanism.

Figs. 25 and 26 illustrate a modification of the holder of the arrangement of Figs. 1 6 to 22 in which the face of the recesses 20 in which the pins 1 9 are disposed are sloped so that rotation of the mechanism causes the pins to engage the faces to resist further movement. Preferably (as shown) the faces comprise two oppositely sloped portions 23 which act as face cams whereby the mechanism is either urged into its operative position or into its inoperative position, the arrangement being such that in the operative position i.e. when the eccentric or cam is engaged with the pick shank the pins are in engagement with the faces of the recesses to bias the eccentric mechanism more firmly into engagement.Preferably in the inoperative position the pins are out of contact with the sloped portions of the recesses as shown diagrammatically in Fig. 26.

In Figs. 27 to 33 of the drawings there is shown the combination of a shanked mineral cutter pick 1, a pick box 4 having a socket 3 adapted to receive the shank 2 of the mineral cutter pick 1 and a latching device in the form of a cam or eccentric 5 mounted in the pick box and rotatable to engage a recess 6 in the tool shank to retain the tool in the pick box.

In general terms this arrangement is as described and illustrated above but in the present arrangement the cam or eccentric 5 is mounted to be disposed within the socket 3 and to extend across the socket from side to side with its axis of rotation disposed centrally of the cross-section of the socket and towards the bottom of the socket. Thus to enable insertion of the tool shank into the socket its lower portion is bifurcated, the two limbs 30, 31 being separated by a central slot 32 extending axially of the shank 2 from its free end, the slot being terminated at is upper end by an enlarged portion 33 having a laterally projecting inclined abutment surface 34 ar ranged to be engaged by the portion 8 of the cam or eccentric to hold the mineral cutter pick in the pick box.The enlargement 33 is bounded at its upper end by a surface 35 extending normally of the axis of the tool shank and which is arranged to be engaged by the cam or eccentric on rotation thereof in the direction to release the inclined abutment to tend to lift the cutter pick from its fully inserted position in the socket. For this purpose the cam or eccentric is located so that when it is positioned as shown in Fig. 27 to allow insertion of the tool shank, it will engage the inner end 35 of the slot to prevent the heel 36 of the pick from engaging the top surface of the pick box. The pick is drawn into the fully inserted position shown in Fig. 28 of the drawings by rotation of the cam or eccentric in the counter-clockwise direction so that it engages the inclined abutment 34 on the tool shank.It will be evident that if the cam or eccentric is rotated in the opposite sense that is to say clockwise it will engage the upper surface 35 of the slot to force the pick away from its seat in the pick box.

It is an advantage of this embodiment of the invention that the pick is secured in the pick box substantially on its centre line rather than by one side.

It is a further advantage of this embodiment of the invention that the pick is reversible in the pick box to face in the opposite cutting direction, since the locking mechanism is centrally disposed and the cam or eccentric can be operated in both directions of rotation.

Figs. 34 and 35 of the drawings illustrate a further example of means for resisting any tendency for the eccentric mechanism to slacken during use. In this embodiment, the shank 2 of the cutter pick 1 is provided with a hard neoprene insert 24 which projects from the recess 6 but which does not project beyond the side of the pick shank. The Dshaped eccentric 1 7 is provided with a flat 25 on its surface so that on turning the eccentric into its operating position (see Fig. 35) the hard insert 24 engages the flat 25 and becomes deformed to an extent whereby it will tend to resist reverse rotation of the eccentric.

The working surface of the insert may incorporate a wear resistant metal member.

Claims

1. The combination of a shanked tool and a holder having a socket for receiving the tool shank to support the tool during use, wherein the holder is provided with a cam or eccentric which can be turned so that a portion of its surface engages the tool shank to retain the shank in the socket.

2. The combination of claim 1, wherein the holder is provided with a cam or eccentric disposed wholly within the socket and which can be turned so that a portion of its surface engages a tool shank in the socket to retain the shank in the socket.

3. The combination according to claim 2, wherein the cam or eccentric extends across the socket from side to side.

4. The combination according to claim 2, wherein the cam or eccentric projects only part-way across the socket.

5. The combination according to claim 3, wherein the tool shank is formed with a slot or a recess extending completely through the shank.

6. The combination of any preceding claim, wherein the shank is formed with an abutment surface for engagement by the cam or eccentric, which abutment surface is inclined with respect to the axis of the tool shank.

7. The combination of claim 6, wherein the slot or recess in the tool shank is terminated with a further abutment face which is arranged to be engaged by the cam or eccentric when it is turned in a direction to release the tool, to tend to lift the tool from the fully inserted position in the socket.

8. The combination of claim 1, wherein the arrangement is such that rotation of the cam or eccentric causes a part thereof to project into the socket.

9. The combination of any preceding claim, wherein the portion of the surface of the cam or eccentric which engages the tool shank is curved.

1 0. The combination of any preceding claim, wherein the rotational axis of the cam or eccentric is arranged substantially normal to the axis of the socket.

11. The combination of any one of claims 1 to 9, wherein the rotational axis of the cam or eccentric is inclined at an acute angle to the socket axis normal.

12. The combination of claim 11 when dependent on claim 8, wherein the socket is rectangular and wherein the rotational axis of the cam or eccentric lies at an acute angle to the side of the socket from which the cam or eccentric is arranged to project.

1 3. The combination of any preceding claim, wherein the cam or eccentric comprises threaded portions engaging correspondingly threaded portions of the holder.

14. The combinations of claim 13, wherein the holder is formed with threaded portions on opposite sides of the socket.

1 5. The combination of any preceding claim, comprising means for limiting rotation of the cam or eccentric in the holder.

16. The combination of claim 15, wherein the means for limiting rotation of the cam or eccentric comprises a pin projecting generally normally from the cam or eccentric and engageable with abutments on the holder.

1 7. The combination of any preceding claim, comprising means for preventing or reducing risk of unintentional slackening of the cam or eccentric during use.

18. The combination of claim 17, wherein the cam or eccentric is screw-threaded into the holder, and wherein frictional inserts are provided between the mating screw threads to prevent unintentional slackening.

1 9. The combination according to claim 16, wherein the pin is arranged to engage a face cam which biases the pin to rotate the cam or eccentric into engagement with the tool shank.

20. The combination according to claim 19, wherein the face cam includes a pair of oppositely sloped portions whereby, according to which portion is engaged by the pin, the cam or eccentric is urged to rotate to bring it either into the operative or non-operative position.

21. A holder for use in the combination defined in any preceding claim, the holder having a socket for receiving the shank of a tool to support the tool during use, and tool retaining means comprising a cam or eccentric rotatable to cause a portion of its surface to engage the tool shank.

22. A holder for use in the combination of any one of claims 2 to 7, the holder having a socket for receiving the shank of the tool to support the tool during use, and tool retaining means comprising a cam or eccentric disposed within the socket and which is rotatable to cause a portion of its surface to engage the tool shank to retain it in the socket.

23. A holder as claimed in claim 22, wherein the cam or eccentric extends across the socket from side to side.

24. A tool for use in the combination defined in any preceding claim, the tool having a shank arranged for reception in a socket in a holder and the shank being formed with a recess the wall of which is adapted to be engaged by a cam or eccentric in the holder to secure the tool in the socket.

25. A tool for use in the combination of any one of claims 2 to 7, the tool having a shank arranged for reception in a socket in a holder and the shank being formed with a recess or slot extending from its free end axially of the socket and having at its inner end an inclined abutment surface for engagement by the cam or eccentric.

26. A tool according to claim 25 wherein the slot or recess is terminated with a further abutment face which is arranged to be engaged by the cam or eccentric when it is rotated in a direction to release the tool to tend to lift the tool from its fully inserted position in the socket.

27. A tool according to claim 26, wherein the slot or recess is disposed substantially centrally of the width of the tool shank.

28. A tool according to claim 27, wherein the tool shank is rectangular in cross-section and wherein the slot or recess emerges from the major face or faces of the tool shank.

29. The combination of claim 1, substantially as hereinbefore described with reference to, and as illustrated in the accompanying drawings.

30. A tool holder according to claim 21, substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

31. A tool according to claim 24, substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.