AU646920B2

AU646920B2 - A tripod

Info

Publication number: AU646920B2
Application number: AU10564/92A
Authority: AU
Inventors: Danny Williams
Original assignee: ACHIEVEMENT HOLDINGS Pty Ltd
Current assignee: ACHIEVEMENT HOLDINGS PTY Ltd
Priority date: 1992-01-29
Filing date: 1992-01-29
Publication date: 1994-03-10
Anticipated expiration: 2012-01-29
Also published as: AU1056492A

Description

P/00/01I Reguladon 3.2

AUSTRALIA

PATENTS ACT 1990 c~ S ;i COMPLETE SPECIFICATION FOR A STANDARD PATENT

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Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: ACHIEVEMENT HOLDINGS PTY. LTD.

276 Treasure Road Welshpool W.A. 6106 MR. DANNY WILLIAMS GRIFFITH HACK CO., Patent and Trade Mark Attorneys of 256 Adelaide Terrace, (6th Fir.), Perth, Western Australia, Australia 6000.

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Standard Complete Specification for the invention entitled: A TRIPOD The following is a full description of this invention, including the best method of performing it known to me:- 2 A TRIPOD The following invention relates to a tripod and in particular, but not exclusively, to a tripod for use in the mining and oil industries for supporting a cable or the like which in turn supports a load above or in a hole or shaft.

There has always been a need to support loads such as drilling heads or recording equipment and men above or within a hole or shaft, particularly in the mining and oil industries. Where tripods are used to support the load, it is critical that the tripod maintain its stability while supporting, raising and lowering of the load. One problem in the use of tripods, is that they tend to become unstable and collapse with disastrous and unfortunately sometimes fatal consequences. There is thus a need to improve the stability of tripods.

Prior art tripods essentially comprised three legs, each leg having one end bolted to the ground with the opposite ends of each leg connected together to form an apex of the tripod. The tripod can be erected over an existing hole or shaft, or alternatively, once the tripod is erected a hole or shaft can be drilled within a footprint defined by the tripod's legs. Typically, a winch is provided to support a load and to .subsequently allow the load to be raised or lowered. A concrete slab to which the winch is mounted, is formed on the ground outside the footprint created by the tripod. A cable to which the load is connected runs from the winch to an upper end of the tripod and then to the hole. Because the load is connected to a point outside the footprint of the tripod, two of the legs of the tripod are in tension and one leg is in compression. As a result of this forced distribution, bolts anchoring the legs, which are in tension, to the ground have a tendency to pull out which has resulted in tripods collapsing and overturning. In one such collapse, the concrete block holding the winch was pulled out of the ground and dragged into the hole, tragically killing two workers.

The present invention was developed in an attempt to alleviate the above described deficiency in the prior art.

According to the present invention there is provided 3 a tripod for supporting a load comprising: three elongate legs, forming a tripod structure; and, mounting means adapted for mounting a winch on a tripod, said winch being of the kind for winding a load supporting cable where said cable can be supported via the apex of the tripod; whereby, in use, a load supported on said cable produces compressive forces in all three legs of the tripod.

Preferably said mounting means located near a free end of said tripod.

Preferably said mounting means supported by one omore of said legs.

Preferably said tripod further comprises a first oooo brace connected between first and second ones of said legs, and wherein said mounting means is supported by said first brace.

In an alternative arrangement said tripod further comprises a plurality of first braces, each one of said first braces being connected between different pairs of said legs, :and wherein said mounting means is supported by one of more of said first braces.

Preferably said tripod comprises a second brace connected between said mounting means and a first point intermediate the length of a first one of said legs.

Preferably said tripod further comprises a third brace connected between said mounting means and a second point intermediate the length of.a second one of said legs, wherein a winch can be mQ'lnted to said mounting means in a region between said first and second braces.

Preferably said tripod further comprises a fourth brace connected between said first and second points.

One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of the tripod from the side; Figure 2 is an elevation view of the tripod from the front; Figure 3 is a side elevation view of the tripod; and, 4 Figure 4 is a plan view of the tripod.

As shown in the accompanying drawings a tripod 2 for supporting a load (not shown) comprises three legs 4a, 4b, 4c (referred to in general as "legs forming a tripod structure and mounting means in the form of a platform 6 adapted for mounting a winch 8 on the tripod 2. The winch 8 is of the kind for winding a load supporting cable 10, the cable being supported via the apex 12 of the tripod 2 for example by a snatch block 14. By virtue of this arrangement when the tripod 2 is in use, the load supported by cable 10 produces compressive forces in all three legs 4 of the tripod 2.

Braces 18a, 18b and 18c are connected between legs 4a, and 4b; 4b and 4c; and, legs 4a and 4c respectively, and lie in the plane substantially perpendicular to the longitudinal axis of the tripod 2. The platform 6 is connected intermediate the length of brace 18a. An end of platform 6 proximate leg 18a is connected to leg 18a by arms 20a and The arms 20a and 20b extend from a first common point 16 intermediate the length of leg 18a to opposite sides of the platform 6. The end of. platform 6 proximate leg 4b is connected to leg 4b by arms 22a and 22b. The arms 22a, 22b extend from a common point 24 intermediate the length of leg 4b to opposite sides of the platform 6. Opposite ends of a brace 26 are connected to legs 4a and 4b at points 16 and 24 respectively.

A leg connecting member 27 for connecting the legs 4 of the apex 12 comprises a U-shaped plate 28 having three cylindrical sleeves 30 extending from one side. The cylindrical sleeves 30 are dimensioned so as to receive an end of respective ones of the legs 4. A plate 32 is connected to ie neath and parallel to plate 28 by means of a rod 34. The rod 34 extends above plate 28 and terminates in a lug 36. The lug 36 is provided with a hole to facilitate lifting of the tripod 2 by means of a crane.

Two lugs 37, 38 (shown in Figure 2) are also connected with a side of plate 32 opposite plate 28. Snatch block is connected with lugs 37, with a second snatch block 5 connected to lug 38.

A cross-bar 42 is attached to a side of the plate 28 opposite the cylindrical sleeves 30. The cross-bar 42 extends parallel to brace 18a and have opposite ends 44 and 46 which extend beyond plate 28. A generally rectangular plate 48 is attached near each end of the cross-bar 42. The plates 48 lie in a plane perpendicular to that containing the braces 18.

As illustrated in Figure 4 the upper portion of the tripod 2 is further stabilised by means of bracing arms 50 to 62. Arm 50 is connected at one end to end 44 of cross-bar 42 and at an opposite end to the U-shaped plate 28 near its apex 63. Arm 52 is connected at one end to end 46 of cross-bar 42 and at an opposite end-to U-shaped plate 28 near its apex 62.

Arm 54 extends between end 44 of cross-bar 42 to leg 4a. Arm 56 extends from end 46 of cross-bar 42 to leg 4b and arms 58, 60 and 62 extend between legs 4a and 4b; legs 4a and 4c and 4b and 4c respectively. (Representations of the arms 50 to 62 have been omitted from Figure 1 for clarity.) A snatch block 64 (shown in Figure 3) is connected with leg 4c near arm 60 on a side opposite by means of a bracket 66.

Two hoists 8, 70 are attached to platform to facilitate raising and lowering of a load into and out of a hole formed beneath the tripod 2. Hoist 8 includes a drum 72 for winding and unwinding the associated cable 10. Cable S. runs from the hoist 8 about snatch block- 14 and to the load to be supported. Hoist 70 includes a drum 76 for winding and unwinding of an associated cable 78. Cable 78 runs from hoist about snatch blocks 39 and 64 to the load. The hoists 8, are orientated so that a longitudinal axis of their respective drums 72 and 76 are substantially perpendicular to the direction of cable pull.

The second end of each of the legs 4 is provided with a ground engaging pad 80. Each of the pads 80 is orientated so that when the tripod 2 is erected, a plane containing respective ones of the pads 80 is substantially parallel with the ground on which the tripod 2 rests. In order to connect the braces 18 to the legs 4 a pair of cleats 82 are welded to 6 each of the legs 4 in the vicinity of its respective free end.

Cleats 84 are also welded to opposite ends of each of the braces 18. The braces 18 are connected with the legs 4 by bolting respective cleats 82 and 84 together. Opposite ends of the arms 20 and 20; 22a and 22b; and the brace 26 are also provided with cleats 86, 88 and 90 respectively. A bracket 92 is connected to each of legs 4a and 4b at points 16 and 24 respectively. The brace 26 is connected between legs 4a and 4b by bolting cleats 90 to a portion of the respective brackets 92. One end of both arms 20 and 20 is bolted via cleats 86 to a second portion of the bracket 92 on leg 4a. Similarly, an end of arms 22a and 22b are bolted to a secorn.d portion of bracket 92 on leg 4b via cleats 88. Elongate brackets 94 are provided at each end of platform 6 to allow connection with cleats 86 and 88 of arms 14a, 14b; and 22a, 22b; respectively.

The tripod 2 is erecZed in the following manner. An end of one of the legs 4 is inserted into a corresponding cylindrical sleeve 30 of the member 27 and bolted in place.

That leg together with the member 27 is then lifted by means of a crane. Another one of the legs 4 is then lifted by a crane then inserted and bolted into a corresponding cylindrical sleeve 30. Thereafter the remaining leg is lifted and then inserted and bolted to the remaining cylindrical sleeve The braces 18 are now connected between respective pairs of the legs 4. Connection is effected by means of bolts passing through corresponding cleats 82 and 84. The platform 6, arms 20, 22a, 22b, and brace 26 are then bolted in place. The legs 4 are further secured in place by means of bolts (not shown) connecting respective ground engaging pads 80 to the ground..

A hole or shaft may now be drilled by transporting men and drilling equipment on the tripod 2. In such instances, it will be readily apparent that each of the legs 4 is in compression. In order to raise or lower a load into or out of a hole or shaft, hoists 8 and/or 70 are bolted to platform 6 and snatch blocks 14 and 40 attached to lugs 37 and 38 respectively. Cable 10 is threaded through snatch block 14, while cable 78 is threaded through snatch blocks 40 and 64.

7 Cable 78 which passes through snatch block 64 forms an emergency cable and is directed by snatch block 64 to run along or near the side wall of a hole or shaft.

It will be appreciated that when a load is connected to either one of cables 10 or 78 that all of the legs 4 of the tripod will be in compression. The compressive forces act along each of the legs 4 in a direction from the apex 12 toward the ground engaging pads 80. Accordingly, no force exists which tends to pull or lift any of the legs from the ground.

From the foregoing description, it will be apparent to those skilled in the relevant arts that numerous modifications and variations may be made without departing from the basic inventive concepts. For exar,1le, in the embodiment, two hoists 8 and 70 are illustrated for raising and lowering L. load. However, such raising and lowering can also be effected by a single hoist or other lifting means connected with brace 8a. In addition, the dual arms 20, 20; and 22a, 22b; may be completely omitted or replaced with respective single arms. Also, the platform 6 may be replaced by any suitable arrangement which will allow connection of a winch or other lifting means to the tripod 2. All such modifications and variations are deemed to be within the scope of the present Sinvention the nature of which is to be determined from the foregoing description.

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Claims

1. A tripod for supporting a load comprising: three elongate legs, forming a tripod structure; and, mounting means adapted for mounting a winch on said tripod, said winch being of the kind for winding a load supporting cable where said cable can be supported via the apex of the tripod; whereby, in use, a load supported on said cable produces compressive forces in all three legs of the tripod.

2. A tripod according to claim 1 wherein, said mounting means is located near a free end of said tripod. iooe

3. A tripod according to claim 2 wherein, said mounting 0000 means is supported by one or more of said legs.

4. A tripod according to any one of claims 1 to 3 further comprising a first brace connected between first and second ones of said legs, and wherein said mounting means is supported by said first brace. 000eo

5. A tripod according to any one of claims 1 to 3 further comprising a plurality of first braces, each one of said first braces being connected between different pairs of said legs, and wherein said mounting means is supported by one of more of said first braces.

6. A tripod according to claim 4 or 5 further comprising a second brace connected between said mounting means and a first point intermediate the length of a first one of said legs.

7. A tripod according to claim 6 further comprising: a third brace connected between said mounting means and a second point intermediate the length of a second one of said legs, wherein a winch can be mounted on said mounting means in a region between said second and third braces. 9

8. A tripod according to claim 7 further comprising: a fourth brace connected between said first and second points.

9. A tripod according to any one of claims 1 to 8 wherein said mounting means comprises a platform.

A tripod according to claim 9 wherein, said second brace comprises first and second arms, said arms extending from said first point to respective opposite sides of said platform.

11. A tripod according to claim 10 wherein said third *0o S. brace comprises third and fourth arms extending from said second point to respective opposite sides of said platform.

12. A tripod according to any one of claims 1 to 11 further comprising leg connecting means for connecting the legs of the tripod at the apex, said leg connecting means including receiving means for receiving an end of each of said legs. p

13. A tripod according to claim 12 wherein said receiving means comprises three cylindrical sleeves, each sleeve adapted to receive a length of respective ones of said legs.

14. A tripod substantially as herein described with reference to and as illustrated in the accompanying drawings. Dated this 29th day of January, 1992. ACHIEVEMENT HOLDINGS PTY. LTD. By its Patent Attorneys: GRIFFITH HACK CO. Fellows Institute of Patent Attorneys of Australia. 10 ABSTRACT A deficiency in presently available tripods is their tendency to collapse and overturn which has catastrophic and sometimes fatal results. This problem arises because a cable supported via the apex of the tripod for supporting a load is wound by a winch which is usually connected to a concrete pad formed in the ground outside the footprint of the tripod. By virtue of this arrangement, one or two of the legs of the tripod are in tension with the remainder being in compression. Such a force distribution results in the legs which are in tension having a tendency to lift from the ground causing the tripod to collapse or overturn. ;A tripod 2 is disclosed for supporting a load above or in a hole or shaft formed beneath the tripod. The tripod comprises three legs, 4a, 4b and 4c which form a tripod structure and mounting means in the form of a platform 6 adapted for mounting a winch 8 on the tripod 2. The winch 8 ir of the kind for winding a load supporting cable 10, the cible being supported via the apex 12 of the tripod 2, for example by a snatch block 14. A plurality of braces 18 is connected between respective pairs of the legs 4a, 4b and 4c. The platform 6 is supported on brace 18a. By virtue of this arrangement, when a tripod 2 is in use, the load supported by the cable 10 produces compressive forces in all three legs of the tripod 2. Accordingly, there are not forces tending to tip the tripod 2 over.