GB1566340A

GB1566340A - Rotary percussion drilling devices

Info

Publication number: GB1566340A
Application number: GB19837/77A
Authority: GB
Original assignee: Hawera Probst Hartmetall Werk Zeugfabrik Ravensburgh KG; Hawera Probst GmbH
Current assignee: Hawera Probst Hartmetall Werk Zeugfabrik Ravensburgh KG; Robert Bosch Power Tools GmbH
Priority date: 1976-05-15
Filing date: 1977-05-11
Publication date: 1980-04-30
Also published as: SE7705496L; DE2621809A1; FR2351242A1; BE854497A; DK204077A; NL7705354A; DE2621809C2; IT1084823B; CH619027A5; JPS5314101A; ATA348277A; AT349411B; FR2351242B1

Abstract

The drilling appliance has a mounting device (1) with a longitudinal bore (4) for a drill, a drive part (5, 6) for connecting to the drilling machine, and a driver member (12) which is movable transversely to the longitudinal bore (4) and lies on a base (9), serving as driving surface, of a recess provided in the drill shank (2, 3). The recess is of segmental design in cross-section with a continuous base (9). Mounted on the drive part (5, 6) is a locking part (15) which can be moved approximately in the axial direction of the drive part (5, 6) into a position locking the driver member (12) in its driving position and into a position releasing the driver member (12) for its movement. The drill is connected to the mounting device (1) in a positive-locking manner in both directions of rotation and can be pushed into the longitudinal bore (4) and pulled out of it without additional tools. The recess is very simple to produce as a result of the segmental design. <IMAGE>

Description

(54) ROTARY PERCUSSION DRILLING DEVICES (71) We, HAWERA PROBST GESELLSCHAFT MIT BESCHRANK TER HAFTUNG + CO., a Kommanditgesellschaft orginised under the Laws of the Federal Republic of Germany, of 77 Schützenstrasse. 798(1 Ravensburg, Federal Republic of Germany, 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:: The invention relates to a percussion drilling device having an arrangement for the detachable rotational fixing of a drill, particularly a rock drill, in a receiving device which has a driving head having a longitudinal bore for receiving a shaft of the drill and a driving pin arranged for connection to a drilling machine coaxially with said longitudinal bore and a rotary drive transmitting member movable in the driving head cross wise to said longitudinal bore, which member is arranged to engage a bottom face of a recess provided in said drill shaft and having its major axis parallel to the axis of the shaft.

A drilling device of this kind (German GmS7.439.278) is known in which the driving of the drill is effected via a bolt consisting of hardened steel or hard metal which is guided movably radially in a cross bore of the driving part and is held in the driving position by a spring band placed on the driving part with elastic tension.

An object of the present invention is on the one hand to facilitate the exchanging of one drill for another drill, and on the other hand to ensure that, after such exchanging, the new drill can be firmly held with sufficient security in the receiving device.

According to the invention therefore, said recess is in cross section substantially segment-shaped, and that on the driving head a securing part is mounted which is movable axially of the driving head between a position at which it locks said member in its driving position and a position at which it releases the member for movement.

thereof.

In consequence of the construction according to the invention the drill inserted in the receiving device can be held satisfactorily by the securing part. The drill in both directions of rotation can be connected in locking manner with the receiving device so that a high degree of working reliability of the drilling device can be ensured. The drill may be inserted into the longitudinal bore of the receiving device simply without additional tools and may be withdrawn from this when the securing part has been moved into the release position. The recess in the drill shaft may in consequence of its crosssectional segment-shaped construction be very simply made so that the manufacture of the drill may be carried out economically.

The invention will now be described further by way of example only and with reference to the accompanying drawings in which: Figure 1 shows one foerm of a drilling device according to he invention partly in section and partly in elevation; Figure 2 shows a section along the line II-II of Figure 1; Figure 3 shows the same section as Figure 2 and illustrates the driving forcess occurring in the driving position of the driving member; Figure 4 shows a radial section through a drilling device in which an edge region of the bottom face of the recess in the drill shaft has become hammered radially outwards; Figure 5 shows a driving head of the driving part of the receiving device; Figure 6 shows the drill shaft of the rock drill in side view; and Figure 7 shows a section on the line VII-VII of Figure 6.

The drilling device has a receiving device 1 and a rock drill the shaft 2 of which has a thickened end zone 3 with which the rock drill is inserted in a longitudinal bore 4 of a driving head 5 of the drilling device. The driving head 5 is part of the receiving device 1 which has a driving pin 6 arranged coaxially to the longitudinal bore 4 and which driving pin has a substantially smaller diameter than the driving head 5 and serves for the connection of the drilling device to a drilling machine, not shown.

For the transmission of the driving tor use from the drilling machine to the drill shatt 2 there is provided in the end zone 3 a drive transmitting recess 8 (Figure 6). The recess 8 is segment-shaped in radial section through the shaft 2. The bottom 9 of the recess 8 forms a drive transmitting face 9 whih extends without discontinuities across the whole width of the drill shaft 2. The face 9 has a distance a from the drill axis 10 (Figure 7) which is at most 40%, and amounts advantageously to about 1/5th, of the diameter d of the end zone 3 of the drill shaft 2. In the embodiment shown the face 9 is made with the aid of a disc cutter the outer cutting face of whih has a working diameter D which advantageously amounts to 60 to 140mm, in the embodiment shown about 120mm.

For the locked driving of the drill there is provided a drive transmitting member 12 formed as a bolt which is guided in a cross bore 13 in the driving head 5. The member 12 is chamfered on its front face and towards the drill shaft (Figure 2) and has a chamfered edge 14 contacting the face 9 which extends diametrically relative to the bolt cross section and the cross bore 13.

In consequence of this construction of the front face of the member 12 a very favourable pressure distribution takes place which is shown more precisely in Figure 3. The chamfered edge 14 lies mainly on the face 9 such that a contact angle d results which suitablv lies between 5 and 450 and advantageously amounts to 20 - 30".

In the embodiment shown, the receiving device 1 and its driving head 5 are surrounded by a securing part 15 movable longitudinally in the axial direction, which securing part 15 is formed as a sleeve and with which the member 12 can be locked in the driving position as shown in Figure 1 in full lines.

The sleeve 15 is, under the pressure of a coil spring 16 arranged coaxially with the driving head 5. held in or urged to a position in respect of the driving head 5 in which a narrow bore section 17 of the axial bore of the sleeve overlaps in the axial direction the cross bore 13 and the member 12 guided therein against which radially acting driving forces exerted thereon are supported.

The sleeve 15 is tubular at its driving side end section 18 and is mounted with sliding seating on an annular collar 19 which lies at the zone at which the driving head 5 merges with the driving pin 6. This annular collar is bounded by an annular shoulder 20 on the drill side extending crosswise to the driving axis on which shoulder the coil spring 16 abuts. An opposite abutment face 21 for the coil spring 16 is defined by an axial end of the section 17. The section 17 as indicated with dot and dash lines in Figure l can be moved so far to the rear by traction on the sleeve 15 that the section 17 releases the member 12 in the radial direction so that the member 12 can be pushed outwards by counter-rotation of the drill to a release position thereof as shown in Figure 1 in dot and dash lines.The drill 2 may then be withdrawn from the longitudinal bore 4 of the driving head 5.

For retaining the member 12 in the release position of the sleeve 15, as indicated in Figure 1 with dot and dash lines, the sleeve 15 has on its drill side an end section 23 reaching from the inner collar 22 defining the section 17 as far as the front end of the sleeve 15, which section 23 allows for sufficient radial deflection of the member 12 and in the driving position engages over an O-ring 24 limiting the axial movement of the sleeve 15, which O-ring is inserted in an annular groove 25 provided in a cylindrical peripheral face of the driving head 5. In the embodiment shown, the O-ring consists of rubber. During operation of the drilling device the O-ring 24 serves also as a seal and prevents drilling dust and the like from reaching the receiving device 1.

The construction of the receiving device 1 shown and in particular of the driving head 5 in conjunction with the sleeve 15 as well as with the member 12, ensures an easily detachable but rotationally fixed connection between the drill and the driving machine whereby the possibility indicated in Figure 4 that the drill shaft upon drilling becomes hammered radially outwards can be substantially avoided. With this undesired hammering out there is formed a burr 31 projecting radially outwards on the edge of the face 9 which prevents the drill from being able to be withdrawn from the longitudinal bore 4 of the driving head 5.

The member 12 is slightly flattened on its periphery 27 and contacts a flat zone of the cross bore 13 adjacent to the peripheral face of the driving head 5 when the member 12 is inserted in to the cross bore 13. This insertion forms a rotational fixing for the member 12 and ensures that this takes up in relation to the face 9 the correct position.

The flattened face 27 of the member 12 serves at the same time as an axial restraint when, for example, the drill, on removal from its drill hole becomes jammed in the hole and for the loosening of same force is applied to the receiving device 1. Then as can be seen from Figure 6 the member 12 bears against the rear side face 7 by which the recess 8 is limited in the axial direction.

Upon drawing back, the member 12 lies flat on the side face 7 of the recess 8 so that the forces occurring upon drawing back are transmitted between flat faces from the member 12 to the side face 7. Thereby in an advantageous manner burr formation on the side face can be obviated which would occur in the case of line contact and the removal of the drill from the receiving device 1 would be rendered more difficult.

The end zone 3 of the drill shaft 2 has a bevel 28 the size of which corresponds approximately to the depth 11 of the recess 8 and enclosing an angle of about 40 , preferably 300, with the axis of the drill shaft. The truncated cone shaped bevel 28 facilitates the introduction of the drill shaft into the receiving device 1 because with the bevel 28 the member 12 can be pushed radially outwards when the sleeve 15 is in the released position indicated in Figure 1 with dot and dash lines.

In addition, by means of the bevel 28 the plane face 29 on the rear front side of the drill shaft is considerably reduced. Thereby despite impact forces exerted with percussion drilling on the plane face 29 a bending of the drill shaft in the region of the recess 8 arranged only on one side can be prevented.

The plane face 29 has thus advantageously for avoiding bending in the region of the recess 8, such a position that a cylindrical core 30 (Figure 6) containing this plane face of the end zone 3 of the drill has a diameter which reaches at the most as far as the face 9 of the recess 8.

The particular advantage of the drilling device described consists in that with a diameter of the end zone 3 provided with the recess 8 of 10 - 12mm depth the drilling tool may have a core or working diameter up to 20mm. Due to the forced locking with the aid of the sleeve 15 the drills used are held in both directions of rotation whereby a considerable increase of the working reliability is achieved. In addition the drill is prevented from being clamped and deformed in the receiving device.

The construction of the receiving device permits furthermore a rapid exchange of drilling tools without additional aids such as keys, wedges or the like.

In the above described embodiment the face 9 is curved slightly convex. It may, however, also be formed flat or slightly concave. Essential only is the fact that the face runs without discontinuities over its whole width.

WHAT WE CLAIM IS: 1. A rotary percussion drilling device having an arrangement for the detachable rotational fixing of a drill, particularly a rock drill, in a receiving device which has a driving head having a longitudinal bore for receiving a shaft of the drill and a driving pin arranged for connection to a drilling machine coaxially with said longitudinal bore, and a rotary drive transmitting member movable in the driving head crosswise to said longitudinal bore, which member is arranged to engage a bottom face of a recess provided in said drill shaft, and having its major axis parallel to the axis of the shaft, characterised in that, the said recess is in cross-section substantially segment-shaped, and that on the driving head a securing part is mounted which is movable axially of the driving head between a position at which it locks said member in its drive transmitting position and a position at which it releases said member for movement thereof.

2. A drilling device according to claim 1, characterised in that the recess in the axial direction of the drill shaft is limited by at least one cross face running perpendicularly to the drill axis.

3. A drilling device according to claim 1 or 2, characterised in that the bottom face of the recess is curved slightly convex in relation to the bore axis.

4. A drilling device according to any one of the claims 1 to 3, characterised in that the bottom face of the recess lies at a distance from the drill axis which amounts at the most to 20% of the diameter of the drill shaft.

5. A drilling device according to any one of the claims 1 to 4, characterised in that on the end of the drill shaft received in said longitudinal bore there is provided a bevelled, conically truncated zone.

6. A drilling device according to claim 5, characterised in that the truncated conical zone encloses with the drill axis an angle of about 40 preferably 30".

7. A drilling device according to claim 5 or 6, characterised in that the plane face bounding the truncated conical zone has a diameter of substantially double the distance of the bottom face of the recess from the drill axias.

8. A drilling device according to claim 7, characterised in that the cylindrical core of the drill shaft having the diameter of the plane face reaches at the most as far as the

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. when, for example, the drill, on removal from its drill hole becomes jammed in the hole and for the loosening of same force is applied to the receiving device 1. Then as can be seen from Figure 6 the member 12 bears against the rear side face 7 by which the recess 8 is limited in the axial direction. Upon drawing back, the member 12 lies flat on the side face 7 of the recess 8 so that the forces occurring upon drawing back are transmitted between flat faces from the member 12 to the side face 7. Thereby in an advantageous manner burr formation on the side face can be obviated which would occur in the case of line contact and the removal of the drill from the receiving device 1 would be rendered more difficult. The end zone 3 of the drill shaft 2 has a bevel 28 the size of which corresponds approximately to the depth 11 of the recess 8 and enclosing an angle of about 40 , preferably 300, with the axis of the drill shaft. The truncated cone shaped bevel 28 facilitates the introduction of the drill shaft into the receiving device 1 because with the bevel 28 the member 12 can be pushed radially outwards when the sleeve 15 is in the released position indicated in Figure 1 with dot and dash lines. In addition, by means of the bevel 28 the plane face 29 on the rear front side of the drill shaft is considerably reduced. Thereby despite impact forces exerted with percussion drilling on the plane face 29 a bending of the drill shaft in the region of the recess 8 arranged only on one side can be prevented. The plane face 29 has thus advantageously for avoiding bending in the region of the recess 8, such a position that a cylindrical core 30 (Figure 6) containing this plane face of the end zone 3 of the drill has a diameter which reaches at the most as far as the face 9 of the recess 8. The particular advantage of the drilling device described consists in that with a diameter of the end zone 3 provided with the recess 8 of 10 - 12mm depth the drilling tool may have a core or working diameter up to 20mm. Due to the forced locking with the aid of the sleeve 15 the drills used are held in both directions of rotation whereby a considerable increase of the working reliability is achieved. In addition the drill is prevented from being clamped and deformed in the receiving device. The construction of the receiving device permits furthermore a rapid exchange of drilling tools without additional aids such as keys, wedges or the like. In the above described embodiment the face 9 is curved slightly convex. It may, however, also be formed flat or slightly concave. Essential only is the fact that the face runs without discontinuities over its whole width. WHAT WE CLAIM IS:

1. A rotary percussion drilling device having an arrangement for the detachable rotational fixing of a drill, particularly a rock drill, in a receiving device which has a driving head having a longitudinal bore for receiving a shaft of the drill and a driving pin arranged for connection to a drilling machine coaxially with said longitudinal bore, and a rotary drive transmitting member movable in the driving head crosswise to said longitudinal bore, which member is arranged to engage a bottom face of a recess provided in said drill shaft, and having its major axis parallel to the axis of the shaft, characterised in that, the said recess is in cross-section substantially segment-shaped, and that on the driving head a securing part is mounted which is movable axially of the driving head between a position at which it locks said member in its drive transmitting position and a position at which it releases said member for movement thereof.

bottom face of the recess.

9. A drilling device according to any one of claims 1 to 8, characterised in that the securing part is movable against spring force into its released position.

1U. A drilling device according to any one of the claims 1 to 9, characterised in that the securing part is a sleeve surrounding the driving head which sleeve is movable along the driving head into the locking position and the release position and that between the sleeve and the driving head there is disposed a coil spring coaxially with this.

11.A drilling device according to claim 10, characterised in that the sleeve has a locking section projecting approximately radially inwards which in the locking position of the sleeve contacts on the member and supports this against the drive force acting radially exerted on the member.

12. A drilling device according to claim 10 or 11, characterised in that the sleeve is tubular on its driving side end section and is mounted there with sliding seating on an annular collar on the transition zone from the driving head to the driving pin of the receiving device.

13. A drilling device according to claim 11 or 12. characterised in that the locking section of the sleeve is arranged in the region of the drill side end of the sleeve and is formed as an inner collar which has a smaller bore diameter than the driving side end section taking the compression spring.

14. A drilling device according to any one of the claims 10 to 13. characterised in that in the cylindrical peripheral face of the driving head on its front part lying outside the sleeve an annular groove is provided in which an annular sprring in particular an O-ring is inserted which serves as an axial stop for the sleeve.

15. A drilling device according to claim 14, characterised in that the sleeve has a bore section widened in diameter with which the sleeve in the locking position engages over the annular resilient member.

16. A drilling device according to any one of the claims 1 to 15. characterised in that the member, on its end zone facing the bottom face of the recess, is chamfered and contacts on the bottom face with the cham fered edge which runs diametrically of the member.

17. A drilling device according to claim 16, characterised in that the drive transmitting member, having a chamfered edge, lies on the bottom face of the recess with a contact angle of between 5 and 45 , preferably between 20 and 30".

18. A drilling device according to any one of the claims 1 to 17, characterised in that the member has a flattened portion on its periphery and is movable in a cross bore in the driving head, and with this flattened portion contacts a flat portion of said cross bore.

19. A drilling device substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings Figures 1 to 3 and 5 to 7.