GB1604668A

GB1604668A - Coal cutter tool holder assembly

Info

Publication number: GB1604668A
Application number: GB1091180A
Authority: GB
Original assignee: WIMET Ltd
Current assignee: WIMET Ltd
Priority date: 1978-02-27
Filing date: 1978-02-27
Publication date: 1981-12-16

Description

COAL CUTTER TOOL HOLDER ASSEMBLY (71) We, WIMET LIMITED, of Torrington Avenue, Conventry CU4 9AD, England, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: In our patent specification 1 344 010 we described and claimed a cutter tool holder assembly comprising a shank to be mounted in a milling cutter for rock drilling and a tool holder mounted in said shank by means of a tongue and groove connection.This tongue and groove connection was said to preferably be a T-slot connection, one part of the connection having a T-shaped tongue projecting from its body and fitting into the groove in the other part of the connection, the cross of the T providing one pair of the contact surfaces of the holder and the body providing respecitvely opposed contact surfaces of the holder.

In the patent specification No. 1 388 503 the same principle is applied to cutter tool holders mounted directly in the milling cutter head of a rock drilling machine. In Patent Specifications Nos. 9074/77 and 4968/77 (Serial No.

1604667) from which the present case is divided-out, the groove of a tongue and groove connection between a rock drilling machine cutter tool holder and the cutter head is narrowed by a projection from one only of its sides and the tongued member is shaped to engage the portion of the projection nearer the base of the groove.

The idea of using a tongue and groove connection for mounting a cutter tool holder on a carrier for the holder is not only applicable to milling cutters, for which purpose it was described in patent specification No 1 344 010: it is likewise useful in coal mining machines. When used for such a purpose, however, it is highly desirable also to have locking means to hold the cutter tool holder and carrier in place when the machine is reversed, and consequently the forces on the cutter tool holder are also reversed and thus tend to loosen the mounting of the holder on the carrier.

According to the present invention we provide a coal cutter tool holder assembly comprising a cutter tool holder and a carrier for said holder on which said holder is mounted by means of a tongue and groove connection comprising opposed divergent contact surfaces of the tongued member of the connection that are respectively engageable with co-acting opposed contact surfaces on the grooved member of the connection, the contact surfaces being arranged so that the two members can be wedgedly connected together by their engagement whilst the end of the tongue is still short of the end of the groove. In an especially preferred embodiment we provide such an assembly having locking means to prevent disengagement of the tool holder from the carrier until the locking means has been released.

Two embodiments of the invention will now be described in further detail, by way of example only, with reference to the accompanying drawings wherein: Figure 1 is a slde view, partly in section, showing a cutter tool holder carried in a cutter head, part only of the cutter head being shown in section; Figure 2 is a section on the line VII-VII of Figure 1; Figure 3 is a front view of the holder of a second embodiment of the invention; Figure 4 is a section through part of the cutter head of the second embodiment of the invention showing a cutter tool holder in position; and Figure 5 is a section on line X-X of Figure 4, In the embodiments shown in the drawings we have departed from the tongue and groove connection described in the parent patent specification No. 1 344 010 in which the mouth of the groove was narrowed by respective projections from opposite sides of the groove, each said projection having opposed contact surfaces which converge together in the direction from which the tongue part is mounted and engage corresponding contact surfaces on the tongue part.

With the above mentioned T-slot connection there is obtained a connection of sufficient strength but considerable costs are connected therewith to an extent that makes it desirable to find less expensive alternatives which still provide a connection of adequate stability and strength.

In Figures 1 and 2 we show a tool holder 10 having a cutting insert 11 of wear resistant material, usually sintered carbide. The holder 10 has a downwardly projecting portion 12 forming a tongue which enters a groove 17 in the cutter head 16. When the holder 10 is in position, shoulders 14 above the downwardly projecting 12 lie against the surface 20 of the cutter head 16 in which the groove 17 is formed.

A cylindrical pin is secured by welding at 29 into a recess at the side of the groove 17, thus leaving a substantially semicylindrical projection 21 which makes an angle of 10 to 15 with the surface 20. A groove 23 is formed in the projecting portion 12 of the holder 10, and this makes the same angle with the line of the shoulders 14. The groove 23 is of such a size that the projection 21 fits slidingly therein.

The lower side of the groove 23 and the shoulders 14 form opposed divergent contact surfaces which are engageable with opposed contact surfaces formed by the lower side of the projection 21 and the surface 20. In the position shown in Figure 1 tool holder 10 is held firmly in the cutter head 16 by wedging between these contact surfaces; it will be noted that the tool holder 10 is thus held in a position where the projecting portion 12 is clear of the base of the groove 17. As the movement of the cutter head is in the direction of the arrow A any force caused by the cutting action will jamb the tool holder more firmly in the cutter head.The tool holder 10 can be removed from the groove 17 by moving it to the right and upwardly and, to enable this to be done, the end of the face of the portion 12 to the left of the line 30 (as seen in Figure 1) is cut back level with the rear of the groove 23.

Figure 1 also shows locking means (shown generally at 27) which prevents disengagement of head 16 and holder 10 when the cutters are moved in the direction opposite to that indicated by arrow A. The locking means 27 comprises a locking pin 24 and resilient material 25 which urges the pin 24 to extend into the mouth 22 of the groove, so that disengagement of head 16 and holder 10 is prevented by the engagement of the pin 24 with wall 28 of the groove. The locking pin 24 is further provided with a resilient tubular pin 26 for keeping the locking pin 24 in a fixed position. For removal of the holder from the head, pin 24 is urged upwards from the groove by a tool engaging pin 26.

The embodiment shown in Figures 3 to 5 differs from that of Figures 1 and 2 in that the downwardly projecting portion 12 of the holder 10 is at right angles or substantially at right angles to the under surface 14 which is to form the upper contact means of the holder. This means that the groove 23 in the projecting por- tion 12 must be cut at an angle, as shown in the drawings, in order to form the wedging angle with the surface 14. The cylindrical pin 21 is mounted as before in a semi-circular recess at the side of the groove 17 in the cutter head 16, where it is welded at 29; it is of course angled in the same way as the groove 23 in the projecting portion 12.

The locking pin 31 is generally J-shaped comprising a longer leg 32, a cross-piece 33 and a shorter leg 34. The two legs are located in bores 35 and 36 in the head 16, the leg 34being fitted with an O-ring 37 to prevent the passage of dirt. The cross-piece 33 lies in an open passage 39 in the head 16 which connects the two bores 35 and 36.

As seen in Figure 5, the shorter leg 34 extends inwardly into the groove 17 in which the projecting portion 12 of the holder 10 lies and prevents its removal when in the position shown. The bore 35 passes through the cutter head 16 and, at the end remote from the passage 39 opens out into a cylindrical chamber 40 of greater diameter in which is located a rubber pad 41. A collar 42 fixed adjacent the outer end of the leg 32 of the locking means 31 bears against the rubber pad 41 which biasses the locking means into the position shown.

It can readily be seen that manual pressure on the end of the locking means 31 adjacent the collar 42 can push this against the bias of the rubber pad and the means will move into a position where the shorter leg 34 lies clear of the groove 17, thus allowing the holder 10 to be removed from the cutter head.

WHAT WE CLAIM IS: 1. A coal cutter tool holder assembly comprising a cutter tool holder and a carrier for said holder on which said holder is mounted by means of a tongue and groove connection comprising opposed divergent contact surfaces ofthe tongued member of the connection that are respectively engageable with co-acting opposed contact surfaces on the grooved member of the connection, the contact surfaces being arranged so that the two members can be wedgedly connected together by their engagement whilst the end of the tongue is still short of the end of the groove.

2. A coal cutter tool holder assembly comprising a cutter tool holder and a carrier for said holder on which said holder is mounted by means of a tongue and groove connection comprising opposed divergent contact surfaces of the tongued member of the connection that are respectively engageable with co-acting opposed contact surfaces on the grooved member of the connection, the contact surfaces being arranged so that the two members can be wedgedly connected together by their engagement whilst the end of the tongue is still short of the end of the groove, locking means being provided to prevent disengagement of the tool holder from the carrier until the locking means has been released.

3. An assembly according to Claim 2 wherein the locking means comprises a pin on the tongued member associated with urging means such that when the tool holder is wedgedly supported in

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. strength. In Figures 1 and 2 we show a tool holder 10 having a cutting insert 11 of wear resistant material, usually sintered carbide. The holder 10 has a downwardly projecting portion 12 forming a tongue which enters a groove 17 in the cutter head 16. When the holder 10 is in position, shoulders 14 above the downwardly projecting 12 lie against the surface 20 of the cutter head 16 in which the groove 17 is formed. A cylindrical pin is secured by welding at 29 into a recess at the side of the groove 17, thus leaving a substantially semicylindrical projection 21 which makes an angle of 10 to 15 with the surface 20. A groove 23 is formed in the projecting portion 12 of the holder 10, and this makes the same angle with the line of the shoulders 14. The groove 23 is of such a size that the projection 21 fits slidingly therein. The lower side of the groove 23 and the shoulders 14 form opposed divergent contact surfaces which are engageable with opposed contact surfaces formed by the lower side of the projection 21 and the surface 20. In the position shown in Figure 1 tool holder 10 is held firmly in the cutter head 16 by wedging between these contact surfaces; it will be noted that the tool holder 10 is thus held in a position where the projecting portion 12 is clear of the base of the groove 17. As the movement of the cutter head is in the direction of the arrow A any force caused by the cutting action will jamb the tool holder more firmly in the cutter head.The tool holder 10 can be removed from the groove 17 by moving it to the right and upwardly and, to enable this to be done, the end of the face of the portion 12 to the left of the line 30 (as seen in Figure 1) is cut back level with the rear of the groove 23. Figure 1 also shows locking means (shown generally at 27) which prevents disengagement of head 16 and holder 10 when the cutters are moved in the direction opposite to that indicated by arrow A. The locking means 27 comprises a locking pin 24 and resilient material 25 which urges the pin 24 to extend into the mouth 22 of the groove, so that disengagement of head 16 and holder 10 is prevented by the engagement of the pin 24 with wall 28 of the groove. The locking pin 24 is further provided with a resilient tubular pin 26 for keeping the locking pin 24 in a fixed position. For removal of the holder from the head, pin 24 is urged upwards from the groove by a tool engaging pin 26. The embodiment shown in Figures 3 to 5 differs from that of Figures 1 and 2 in that the downwardly projecting portion 12 of the holder 10 is at right angles or substantially at right angles to the under surface 14 which is to form the upper contact means of the holder. This means that the groove 23 in the projecting por- tion 12 must be cut at an angle, as shown in the drawings, in order to form the wedging angle with the surface 14. The cylindrical pin 21 is mounted as before in a semi-circular recess at the side of the groove 17 in the cutter head 16, where it is welded at 29; it is of course angled in the same way as the groove 23 in the projecting portion 12. The locking pin 31 is generally J-shaped comprising a longer leg 32, a cross-piece 33 and a shorter leg 34. The two legs are located in bores 35 and 36 in the head 16, the leg 34being fitted with an O-ring 37 to prevent the passage of dirt. The cross-piece 33 lies in an open passage 39 in the head 16 which connects the two bores 35 and 36. As seen in Figure 5, the shorter leg 34 extends inwardly into the groove 17 in which the projecting portion 12 of the holder 10 lies and prevents its removal when in the position shown. The bore 35 passes through the cutter head 16 and, at the end remote from the passage 39 opens out into a cylindrical chamber 40 of greater diameter in which is located a rubber pad 41. A collar 42 fixed adjacent the outer end of the leg 32 of the locking means 31 bears against the rubber pad 41 which biasses the locking means into the position shown. It can readily be seen that manual pressure on the end of the locking means 31 adjacent the collar 42 can push this against the bias of the rubber pad and the means will move into a position where the shorter leg 34 lies clear of the groove 17, thus allowing the holder 10 to be removed from the cutter head. WHAT WE CLAIM IS:

1. A coal cutter tool holder assembly comprising a cutter tool holder and a carrier for said holder on which said holder is mounted by means of a tongue and groove connection comprising opposed divergent contact surfaces ofthe tongued member of the connection that are respectively engageable with co-acting opposed contact surfaces on the grooved member of the connection, the contact surfaces being arranged so that the two members can be wedgedly connected together by their engagement whilst the end of the tongue is still short of the end of the groove.

the carrier, said urging means causes said pin to project into said groove whereby to prevent unwedging movement of the holder.

4. An assembly according to Claim 2 wherein the locking means comprises a Jshaped pin located in the grooved member and movable between a first position in which the shorter leg of the pin extends into the groove and blocks the unwedging movement of the tool holder and a second position in which this leg ceases to block such movement, the pin being resiliently biassed towards the first position but readily movable against this bias into the second position to allow the tool holder to be removed.

5. An assembly according to any one of the preceding claims in which the groove has a closed base and the tongue is supported clear of the base.

6. An assembly according to any one of the preceding claims in which the tongued member is the tool holder and the grooved member is the carrier.

7. An assembly according to Claim 6 wherein the opposed divergent contact surfaces of the tongued member are formed by a groove in a projecting portion on the tool holder and a pair of shoulders spaced from the said groove.

8. An assembly according to Claim 4 or Claim 5 wherein the opposed contact surfaces on the carrier are formed by a in set in one wall of the groove and the surface in which the groove is formed.

9. A coal cutter tool holder assembly consstructed and arranged for use substantially as shown in Figures 1 and 2 of the accompanying drawings and described herein with reference thereto.

10. A coal cutter tool holder assembly constructed and arranged for use substantially as shown in Figures 3 to 5 of the accompanying drawings and described herein with reference thereto.