GB1587774A - Means for connecting two parts through a spigot and socket joint - Google Patents

Description

(54) MEANS FOR CONNECTING TWO PARTS THROUGH A SPIGOT AND SOCKET JOINT (71) We, SANDVIK AKTIEBOLAG, of Fack, S-811 01, Sandviken 1, Sweden, a Joint Stock Company organised in accordance with the laws of Sweden, 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 statement:- This invention relates to means for detachably connecting and locking a first part having a cylindrical shank into a corresponding hole in a second part, the said means being suitable for use in, for instance, coal mining machines. The second part in the form of a holder is fastened to the machine, while the first part comprising a tool is detachably fastened into the second part.

A very important requirement in coal mining machines and other similar machines is that it should be possible to take the tool out of and place it back into the holder with a minimum of handling so that the standstill time of the machine is reduced.

This invention meets the mentioned requirement, and, at the same time, the tool is safely and reliably kept in its place in the holder. This is important because there must be no risk that the tool gets loose during operation of the machine, since this would not only lead to large expenses for replacing the lost tool but also substantially reduce the efficiency of the machine.

German Federal Republic Patent Specification No. 2011 359 describes a device for connecting a tool with a holder provided with a locking device. The tool shank has rectangular form and is provided with a recess for co-operation with the locking device. When fastened the tool is put into the holder in which there is a corresponding rectangular hole, and is forced past the locking device which snaps into the recess.

Owing to design of the locking device and the recess there is a great risk for the tool to be wrenched off when heavily loaded. In addition, the tool is sensitive to side forces because of the rectangular form of the shank, which fact can also lead to the tool getting loose during operation.

Another publication, U.S. Patent No.

3 796 464, discloses a tool which is rotatably fastened in a holder and provided with a cylindrical shank. In a groove extending around the whole periphery of the shank engages a metal pin which is embedded in an elastic material permitting the pin to yield aside when the tool is inserted into the holder. This device does not permit a reliable attachment of the rotatable tool since the elastic material rapidly deteriorates, resulting in a risk of the tool getting loose from the holder.

According to the present invention we provide means for detachably connecting and locking a first part having a cylindrical or frustoconical shank into a corresponding hole in a second part, the said second part having a locking pin eccentrically positioned in the hole with its longitudinal direction perpendicular to that of the hole and the first part having a groove for engagement with the locking pin, which groove extends circumferentially round part of the periphery of the shank and a bevelled portion at the end of the shank of such depth and length that the shank can be pushed into the hole until the groove is at the level of the locking pin and then rotated to lock the first part in position with the pin in the groove.

By this invention, a very safe fastening of the two parts is achieved. In addition, the exchange of the first part can be done easily and quickly. Because of the form of the shank of this part, the connnection enables forces from all directions to be absorbed without the functional efficiency being reduced.

One embodiment of the invention will now be further described with reference to the accompanying drawings, in which: Fig. 1 shows a tool; Fig. 2 is a section along the line 2-2 of Fig. 1; Fig. 3 shows a holder for the tool; Fig. 4 is a section along the line 44 of Fig. 3; and.

Fig. 5 shows a locking pin.

The first part comprises a tool consisting of a cutting part 1 with a cylindrical shank 2. In the lower part of the shank there is a bevelled portion 3 extending in the axial direction. In the shank there is also a groove 4 extending round part of the periphery of the shank and merging into the bevelled portion 3 by an intermediate groove portion 4a.

The second part comprises a holder 5, in which there is a hole 6 having a diameter fitted to the diameter of the tool shank.

Excentrically in the hole there is positioned a locking pin 7 for instance made of steel which pin is fixed in a bore 9 in the holder 5. As can be seen in Fig. 4 the diameter of the pin 7 is less than that of the bore 9 to allow for some lateral movement of the centre of the pin. This can be readily achieved by making the pin of dumb-bell shape (as shown) with end flanges; the pin can readily be fixed in the bore 9 by a spot weld 8.

To fasten the tool, it is inserted into the holder, the bevelled portion 3 permitting the lower part of the shank to pass the locking pin 7. When the tool is completely inserted into the holder, i.e. when the cutting part 1 abuts the holder 5, the groove 4 is in line with the locking pin 7. Thereupon the tool is turned in relation to the holder. Since the distance B (see Fig. 2Y is smaller than the distance A the locking pin 7 will be flexed aside. When continuing the turning to the stop position which occurs after a turn of 90" the locking pin will spring back somewhat, as the distance C is somewhat larger than B.As the distance between the bottom of the groove at its maximum depth C and the diametrically opposite surface of the shank is greater than the distance between the surface of the locking pin nearest the centre of the hole when the shank is not inserted and the position of the diametrically opposite surface of the shank when this is inserted and in locked position, the tool is now locked in position and is held by the spring force of the locking pin.

It will be noted that the end of the groove, i.e. that part of the groove in which the locking pin lies when the first part is in locked position has a bottom which lies along a chord to the cylindrical shank, 2.

The invention is of course not limited to the described embodiment but can be modified within the scope of the following claims.

The invention is neither limited to the indicated area of use but can be applicable within the whole field of mining industry as well as for several types of drilling aggregates. For instance, the tools of an aggregate for raise boring can be attached by means of this type of connection. Furthermore, detachable bearing pins for roller drill bits can be attached and locked by this connection. Moreover, this type of connection can replace a threaded connection and also be used in conical connections for counteracting rotation between the conical elements.

WHAT WE CLAIM IS:- 1. Means for detachable connecting and locking a first part having a cylindrical or frustoconical shank into a corresponding hole in a second part, the said second part having a locking pin eccentrically positioned in the hole with its longitudinal direction perpendicular to that of the hole and the first part having a groove for engagement with the locking pin which groove extends circumferentially round part of the periphery of the shank and a bevelled portion at the end of the shank of such depth and length that the shank can be pushed into the hole until the groove is at the level of the locking pin and then rotated to lock the first part in position with the pin in the groove.

2. Means according to claim 1 wherein the distance between the bottom of the groove. at its maximum depth and the diametrically opposite surface of the shank is greater than the distance between the surface of the locking pin nearest the centre of the hole when the shank is not inserted and the position of the diametrically opposite surface of the shank when this is inserted and in locked position, the pin being mounted so that it can flex slightly.

3. Means according to claim 1 or claim 2, wherein the part of the groove in which the locking pin lies when the first part is in locked position has a bottom which lies along a chord at a cross-section of the shank.

4. Means according to any one of the preceding claims wherein the groove extends past the edge of the bevelled portion, the depth of the groove being at a maximum at the point where it contacts the centre of the pin when the first part is in locked position.

5. Means according to any one of the preceding claims, wherein the groove and the locking pin are on the same level when the first part is wholly inserted into the second part.

6. Means according to any one of the preceding claims, wherein the locking pin is made of steel and is fixed in the bore in the second part by means of a weld.

7. Means according to claim 6 wherein the pin has a flange at each end and is inserted into a hole capable of accepting the flanges with a sliding fit.

8. Means for detachably connecting and locking two parts together substantially as described with reference to the accompanying drawings.

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

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. Fig. 4 is a section along the line 44 of Fig. 3; and. Fig. 5 shows a locking pin. The first part comprises a tool consisting of a cutting part 1 with a cylindrical shank 2. In the lower part of the shank there is a bevelled portion 3 extending in the axial direction. In the shank there is also a groove 4 extending round part of the periphery of the shank and merging into the bevelled portion 3 by an intermediate groove portion 4a. The second part comprises a holder 5, in which there is a hole 6 having a diameter fitted to the diameter of the tool shank. Excentrically in the hole there is positioned a locking pin 7 for instance made of steel which pin is fixed in a bore 9 in the holder 5. As can be seen in Fig. 4 the diameter of the pin 7 is less than that of the bore 9 to allow for some lateral movement of the centre of the pin. This can be readily achieved by making the pin of dumb-bell shape (as shown) with end flanges; the pin can readily be fixed in the bore 9 by a spot weld 8. To fasten the tool, it is inserted into the holder, the bevelled portion 3 permitting the lower part of the shank to pass the locking pin 7. When the tool is completely inserted into the holder, i.e. when the cutting part 1 abuts the holder 5, the groove 4 is in line with the locking pin 7. Thereupon the tool is turned in relation to the holder. Since the distance B (see Fig. 2Y is smaller than the distance A the locking pin 7 will be flexed aside. When continuing the turning to the stop position which occurs after a turn of 90" the locking pin will spring back somewhat, as the distance C is somewhat larger than B.As the distance between the bottom of the groove at its maximum depth C and the diametrically opposite surface of the shank is greater than the distance between the surface of the locking pin nearest the centre of the hole when the shank is not inserted and the position of the diametrically opposite surface of the shank when this is inserted and in locked position, the tool is now locked in position and is held by the spring force of the locking pin. It will be noted that the end of the groove, i.e. that part of the groove in which the locking pin lies when the first part is in locked position has a bottom which lies along a chord to the cylindrical shank, 2. The invention is of course not limited to the described embodiment but can be modified within the scope of the following claims. The invention is neither limited to the indicated area of use but can be applicable within the whole field of mining industry as well as for several types of drilling aggregates. For instance, the tools of an aggregate for raise boring can be attached by means of this type of connection. Furthermore, detachable bearing pins for roller drill bits can be attached and locked by this connection. Moreover, this type of connection can replace a threaded connection and also be used in conical connections for counteracting rotation between the conical elements. WHAT WE CLAIM IS:-

1. Means for detachable connecting and locking a first part having a cylindrical or frustoconical shank into a corresponding hole in a second part, the said second part having a locking pin eccentrically positioned in the hole with its longitudinal direction perpendicular to that of the hole and the first part having a groove for engagement with the locking pin which groove extends circumferentially round part of the periphery of the shank and a bevelled portion at the end of the shank of such depth and length that the shank can be pushed into the hole until the groove is at the level of the locking pin and then rotated to lock the first part in position with the pin in the groove.

2. Means according to claim 1 wherein the distance between the bottom of the groove. at its maximum depth and the diametrically opposite surface of the shank is greater than the distance between the surface of the locking pin nearest the centre of the hole when the shank is not inserted and the position of the diametrically opposite surface of the shank when this is inserted and in locked position, the pin being mounted so that it can flex slightly.

3. Means according to claim 1 or claim 2, wherein the part of the groove in which the locking pin lies when the first part is in locked position has a bottom which lies along a chord at a cross-section of the shank.

4. Means according to any one of the preceding claims wherein the groove extends past the edge of the bevelled portion, the depth of the groove being at a maximum at the point where it contacts the centre of the pin when the first part is in locked position.

5. Means according to any one of the preceding claims, wherein the groove and the locking pin are on the same level when the first part is wholly inserted into the second part.

6. Means according to any one of the preceding claims, wherein the locking pin is made of steel and is fixed in the bore in the second part by means of a weld.

7. Means according to claim 6 wherein the pin has a flange at each end and is inserted into a hole capable of accepting the flanges with a sliding fit.

8. Means for detachably connecting and locking two parts together substantially as described with reference to the accompanying drawings.

9. A part having a cylindrical or frusto

conical shank, a groove which extends circumferentially round part of the periphery of the shank and a bevelled portion at the end of the shank, and the said part being a first part of means according to any of claims 1 to 7.