WO1992014066A1

WO1992014066A1 - A joining system

Info

Publication number: WO1992014066A1
Application number: PCT/AU1992/000044
Authority: WO
Inventors: Darrell William Geatches
Original assignee: MINING CONCEPTS Pty Ltd
Current assignee: MINING CONCEPTS Pty Ltd
Priority date: 1991-02-07
Filing date: 1992-02-06
Publication date: 1992-08-20
Anticipated expiration: 1993-08-07
Also published as: NZ241550A; ZA92825B

Abstract

A joining system is disclosed in which a first member (1) is connectable to a second member (2). Formed within the first member (1) is a female receptacle (3) which includes at least one curved inner surface (6). Extending from the second member (2) is a male protrusion (8) arranged for insertion into the receptacle (3) and includes a first curved outer surface (9) complementing the curved inner surface (6) and a second curved outer surface (10) opposite the first curved outer surface (9). The interengagement of the surfaces (6) and (9) permits a longitudinal connection between the members (1) and (2) with the curvature of the surface (10) permitting ready insertion of the protrusion (8) into the receptacle (3).

Description

A JOINING SYSTEM Field of the Invention

The present invention relates to a system for joining two members and in particular discloses an arrangement that permits transmission of longitudinal and twisting forces between the members. Background Art

In mining operations, it is commonly required to drill into the face of the mine for the setting of explosive charges and the like. Long bores are drilled using a drill head that -is attached via a number of connecting lengths of rod which return to the drilling machine located in the mine cavity. Typically, the connecting rods are coupled using a screw thread and/or nut arrangement.

However, problems exist with the known arrangement in that through use, and the constant twisting associated with the drilling rods, the screw threads can become jammed and their connection and disengagement can at times be quite difficult and time consuming. Object and Summary of the Invention

It is an object of the present invention to substantially overcome, or ameliorate the above entioned difficulties through provision of a system for joining two members that requires no additional fastening device.

In accordance with the present invention there is disclosed a system for joining a first member and a second member, said system comprising: a female receptacle in said first member having a (first) curved inner surface; and a male protrusion extending from said second member and having a first curved outer surface complementing said first curved inner surface, and a second curved outer surface opposite said first curved surface, said second curved outer surface being sufficiently curved so as to permit insertion of said protrusion into said receptacle for joining said members. Preferably, the members are intended for longitudinal alignment and connection and preferably are connecting rods of a drilling device. Brief Description of the Drawings

Two embodiments of the present invention will now be described with reference to the drawings in which: Fig. 1 is a perspective view of a first embodiment showing the two joining members;

Fig. 2 is a perspective view of second embodiment showing the two joining members; Fig. 3 is a transverse cross-section of the two joined members of the second embodiment; and

Fig. 4 is a longitudinal end view of the male joining member of Fig. 2.

Referring to Fig. 1, a first member .1 and a second member 2 are shown arranged for longitudinal joining. The members 1 and 2 in this embodiment are of a square cross-sectional shape but can have any cross-sectional shape as determined by the specific application.

The first member 1 includes a female receptacle 3 of substantially cubic shape. The receptacle 3 is distanced from the longitudinal wall faces 4 of the member 1 by an abutment surface 5 arranged at the end of the member 1.

The receptacle 3 includes a curved inner surface 6, concave in shape, that extends from the opening of the receptacle 3 adjacent the abutment surface 5 to a location 15 short of an inner rear wall 7 thereof.

The second member 2 includes a substantially elongate male protrusion 8 adapted for insertion into the female receptacle 3. The protrusion 8 is generally quasi-cubic and substantially corresponds to the inner shape of the receptacle 3. The protrusion 8 includes a first curved outer surface 9, convex in shape that complements the curved inner surface 6 of the receptacle 3. The protrusion 8 also includes a second curved surface 10, arranged opposite the first curved surface 9 that permits entry of the protrusion 8 into the receptacle 3. The protrusion 8 is distanced from the longitudinal faces 11 of the member 2 by an abutment surface 12 (illustrated in phantom) that corresponds, and when the members 1 and 2 are joined, abuts with the abutment surface 5 of the first member 1. The protrusion 8 also includes a front face 13 that extends between the curved surfaces 9 and 10 and is adapted to abut the rear wall 7 of the receptacle 3. The joining of the members 1 and 2 can now be described. The members 1 and 2 are arranged so that the curved surfaces 6 and 9 are adjacent. The leading edge 14 adjacent the front face 13 and curved surface 9, is then, without longitudinal alignment between the members 1 and 2, inserted into the recess 3 to abut the surface 6. The shape of the second curved surface 10 permits full insertion of the protrusion 8 into the receptacle 3 through urging of the surface 10 upon a surface 16 opposite the surface 6 within the receptacle 3. The protrusion 8 is then pushed into the receptacle 3 by sliding the complementary surfaces 6 and 9 across each other. This sliding motion brings the members 1 and 2 into longitudinal alignment. When fully inserted, the front face 13 abuts the rear wall 7 and the abutment surfaces 5 and 12 are in contact. This joining arrangement has a number of advantages. Firstly, any longitudinal compression between the members 1 and 2 is absorbed by the abutting surfaces 7 and 13, and 5 and 12. These surfaces define almost all the cross-sectional area of the members 1 and 2, with the exception of that area lost through curved surface 10. Accordingly, the longitudinal compressive strength of the members is not substantially reduced within the join. Also, the join retains much longitudinal tensile strength through friction between the complementary curved surfaces 6 and 9 and the requirement for longitudinal misalignment for disengagement. Also, the arrangement has substantial torsional strength as provided by the abutting side walls of the receptacle 3 and protrusion 8.

It will be understood by those skilled in the art that the embodiment shown in Fig. 1 can be used for the joining of any two members at any orientation, however, it is much preferred that the members have preferably a longitudinal alignment when joined.

The embodiment shown in F1gs. 2, 3 and 4 Is specifically adapted for drilling operations in mines.

Fig. 2 shows a male connecting piece 20 of a drilling connecting rod 21 and a female connecting piece 23 of a rod 22. The rods 21,22 are of hexagonal longitudinal cross-section as better seen in Fig. 4 and include a feedwater line or air passage 22 passing along their longitudinal axis for the supply of cooling and flushing feedwater or air to a drilling bit (not illustrated).

As better seen in Fig. 3, the connecting pieces 20 and 23 are joined to their respective rods 21 and 22 at recesses 40,39 formed therebetween, by threaded connections 38 and 37 respectively. This permits ease of manufacture of the rods 21,22 and pieces 20,23 separately, whilst also permitting ease of maintenance through the replacement of broken or damaged connections. Alternatively, the connecting pieces 20,23 can be integrally formed with their respective rods 21,22. Also, welded connections can be used, particularly to increase the strength of the threaded connections 37,38. Generally a single connecting rod has a male connecting piece 20 at one end and a female connecting piece 23 at the other.

Returning to Fig. 2, the male connecting piece 20 is formed with a hexagonally shaped abutment surface 35 from the centre of which extends a elongate male protrusion 50 having opposite curved outer surfaces 26 and 34. The protrusion 50 substantially corresponds in shape to an extent to the hexagonal shape of the rod 21 of which two side faces 30 and 31, adjacent the curved surface 26, correspond. The curved surface 34, at the surface 35, substantially corresponds to a portion of a hexagon, but, as it extends towards a front face 32 of the protrusion 50, the surface 34 obtains a bell-shaped profile. This is best seen in Fig. 4. This shaping acts to increase the contact surface area between the pieces 20 and 23 when joined.

The male connecting piece 20 has a channel or bore 41 which aligns with the feedwater line 22 of the rod 21 at the connection 38. The channel 41 extends, substantially centrally through the connecting piece 20 and ends in an aperture 42, seen in Fig. 2. In view of the shape of the front face 32 and the desirability of locating the aperture 42 centrally on the face 20, the channel 41 is slightly Inclined, when compared with the feedwater line 22, as best seen in Fig. 3.

The female connecting piece 23 includes a surface 36 arranged to abut with the surface 35. A receptacle 27 is provided to receive the male protrusion 50 of the piece 20 and has a curved convex inner surface 25 configured to meet the concave surface 26. Unlike the first embodiment, the receptacle 27 includes an additional curved inner surface 33 which is configured to meet the surface 34, thereby increasing contact between the two pieces 20 and 23 as alluded to above.

The receptacle 27 has a rear wall 28 of shape similar to the front face 32 but of slightly larger size about the curved surface 33. This creates a small vacant space 43, seen in Fig. 3, which provides for ease of insertion and extraction, in the same manner as the first embodiment, of the piece 20 into and out of the piece 23. So as to permit the communication of feedwater between the pieces 20,23, the female connecting piece 23 has a water channel or bore 44 configured to meet with the aperture 42. The channel 44, like to channel 41 is also inclined, so as to meet with the feedwater line 22 of the rod 24. A rubber grommet 45, seen in Fig. 2, provides sealing between the pieces 20 and 23 and is arranged to be seated within a suitably shaped recess 46, which defines an aperture, at the end of the channel 44.

On insertion of the protrusion 50 into the receptacle 27, the front face 32 engages the grommet 45, forcing it- into the recess 46 such that the face 32 also engages the rear wall.

In a similar manner, annular washers (not illustrated) can also be used to ensure a water tight seal at the threaded connections 37 and 38.

The foregoing describes only two embodiments of the present inventions and modifications, obvious to those skilled in the art can be made thereto without departing from the scope of the present invention. For example, it is apparent that the curved surface 6 can be concave in shape provided the surfaces 9 and 10 on the protrusion 8 are appropriately transformed. Industrial Applicability The present Invention is useful in joining rods and like members and particularly use in mining and drilling operations.

Claims

1. A system for joining a first member and a second member, said system comprising: a female receptacle in said first member having a (first) curved inner surface; and a male protrusion extending from said second member and having a first curved outer surface complementing said first curved inner surface, and a second curved outer surface opposite said first curved surface, said second curved outer surface being sufficiently curved so as to permit insertion of said protrusion into said receptacle for joining said members.

2. A system as claimed in claim 1, wherein upon insertion of said protrusion into said receptacle, said first outer curved surface engages and slides across said first curved inner surface.

3. A system as claimed in claim 1, wherein the abutment between said receptacle and said second curved outer surface urges said first curved out surface towards said first curved inner surface.

4. A system as claimed in claim 3, wherein said receptacle has a second curved inner surface opposite said first curved innner surface curved in a manner substantially complementary to said second curved outer surface.

5. A system as claimed in claim 1, wherein said first curved inner surface has a shape selected from the group consisting of concave and convex surfaces.

6. A system as claimed 1n claim 1, wherein a face arranged at the free end of said protrusion is arranged to abut a rear wall of said receptacle.

7. A system as claimed in claim 1, wherein adjacent said protrusion said second member comprises a first abutment surface adapted to abut a corresponding second abutment surface of said first member adjacent said receptacle.

8. A system as claimed in claim 7, wherein said first and said second abutment surfaces surround said protrusion and said receptacle respectively.

9. A system as claimed in claim 1, wherein each of said members includes a bore passing therethrough and adapted to permit fluid communication through said first member to said second member, or vice versa, when said members are joined.

10. A system as claimed in claim 9, wherein said fluid is selected from the group consisting of water and air.

11. A system as claimed in claim 9 or 10, wherein said bore of said first member ends with a first aperture opening into said receptacle, and said bore of said second member ends with a second opening at said protrusion, said apertures having corresponding alignment locations upon joining of said members.

12. A system as claimed in claim 11, wherein said first aperture is formed in a rear wall of said receptacle and said second aperture is formed at the free end of said protrusion.

13. A system as claimed in claim 12, wherein said first aperture includes a recess thereabout within which a sealing means can be positioned for compression between said rear wall and said peripheral face upon joining of said members to seal the interconnection of said bores.

14. Apparatus comprising at least one of said first member as defined by the system of claim 1.

15. Apparatus comprising at least one of said second member as defined by the system of claim 1.

16. A connecting device incorporating the system as claimed in claim 1, said device comprising one said first members connected to a main body, and one said second member connected to said main body.

17. A connecting device as claimed in claim 16, wherein said body is a rod and said members are arranged at opposite ends of said rod.

18. A connecting device as claimed in claim 17, wherein said protrusion and receptacle are longitudinally aligned to permit joining of said connecting device to another, like connecting device.

19. A connecting device as claimed in claim 17 or 18, wherein a said rod and said members have a bore passing therethrough.