LOCKING PIN FOR SHORING SUPPORT STRUCTURE

Abstract

A locking pin 240 for an extendable structure, such as a acrow prop, having a first protrusion 244 and a second protrusion 248 extending from the shaft 242 of the pin, the first protrusion 244 extending from an intended lower surface of the shaft and having a curved inner wall facing towards the centre of the shaft and the second protrusion 248 extending from an intended upper surface of the shaft 242 and forming a box-like structure having a recess 245 for receipt of a leash 250.

Claims

1. A locking pin for an extendable structure comprising: an elongated shaft member, the shaft member having at least one protrusion extending from an intended upper or lower surface thereof.

2. The locking pin as claimed in claim 1, wherein two protrusions extend from the shaft member wherein a first protrusion extends from an intended lower surface of the shaft member and a second protrusion extends from an intended upper surface of the shaft member.

3. The locking pin as claimed in claim 1, wherein the shaft member and protrusions are formed of a load bearing metallic material, selected from forged or machined steel.

4. The locking pin as claimed in claim 1, wherein the first protrusion has an inner wall facing towards the centre of the shaft and an opposing outer wall, the inner and outer walls defining opposing side walls.

5. The locking pin as claimed in claim 4, wherein the outer wall extends substantially perpendicularly to the longitudinal axis of the shaft and wherein the inner facing wall is curved.

6. (canceled)

7. The locking pin as claimed in claim 5, wherein the radius of curvature corresponds substantially to a curvature of an inner tube of a shoring structure in relation to which the locking pin is to be used.

8. The locking pin as claimed in claims 4, wherein the inner and outer facing walls of the first protrusion extend across the whole of the underside of the shaft, i.e., at the point where it meets the shaft the protrusion has a width corresponding substantially to the diameter of the shaft.

9. The locking pin as claimed in claims 4, wherein each side wall of the protrusion tapers to an apex at the end of the protrusion.

10. The locking pin as claimed in claims 2, wherein the second protrusion extends substantially perpendicularly from an intended upper surface of the shaft, the protrusion being spaced laterally from the first protrusion towards an outer end of the shaft.

11. The locking pin as claimed in claim 2, wherein the second protrusion forms a box-like structure having four sides extending upwardly from the shaft, wherein the width of each side is slightly less than the diameter of the shaft, the protrusion having a slight tapering towards it free end.

12. (canceled)

13. The locking pin as claimed in claims 2, wherein the second protrusion has a recess or hole through its centre for receipt of a leash.

14. (canceled)

15. The locking pin as claimed in claim 2, wherein the second protrusion has a recess or hole through its centre for receipt of a leash, wherein the leash is formed from a wire.

16. The locking pin as claimed in claim 2, wherein the second protrusion has a recess or hole through its centre for receipt of a leash, and the leash extends upwardly from the protrusion and shaft.

17. The locking pin as claimed in claims 2, wherein the second protrusion has a recess or hole through its centre for receipt of a leash, wherein the leash is provided with a loop spaced apart from the shaft.

18. The locking pin as claimed in claim 2, wherein the second protrusion has a recess or hole through its centre for receipt of a leash, wherein the leash is provided with a loop spaced apart from the shaft and the loop is formed by the provision of a ferrule which is cold formed onto the junction of the loop of the leash.

19. The locking pin as claimed in claim 1, wherein one or both ends of the elongated shaft includes a taper for mating with a central bore of a pinion gear.

20. An extendable structure comprising: an outer tube having a threaded region with opposing longitudinal slots therethrough; an inner tube slidable within the outer tube and having a plurality of pairs of transverse holes at spaced apart intervals; a locking pin according to claim 1, the pin being receivable through the slots of the outer tube and a pair of transverse holes of the inner tube; and a collar mounted on the threaded region and being rotatable to raise and lower the pin within the slots, the protrusion of the pin being received between the collar and the inner tube; wherein the collar includes a driven member for mating with a driving member connectable to an actuator, actuation of the driving member causing rotation of the driven member to effect rotation of the collar.

21. The extendable structure as claimed in claim 20, wherein the driven member is a bevel gear provided on an upper or lower surface of the collar and the driving member is a pinion gear that meshes with the bevel gear provided on the collar, the pinion gear receiving an end of the locking pin.

22. The extendable structure as claimed in claim 21, wherein an outer surface of the pinion gear is provided with a recess or protrusion for mating with a corresponding protrusion or recess of an actuator.

23. A kit of parts for adapting an existing extendable structure, particularly but not exclusively a shoring support structure, the kit comprising a collar with a bevel gear on an upper or lower surface thereof, a locking pin according to claims and a pinion gear.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which:

[0034] FIGS. 1A, 1B and 1C are respectively front and rear perspective views and a cross-sectional view of a shoring support structure fitted with a collar and bevel gear according to the prior art;

[0035] FIG. 2A is an isometric view of a locking pin according to an embodiment of the present invention;

[0036] FIG. 2B is a side view of the locking pin of FIG. 2A;

[0037] FIG. 2C is an end view of the locking pin of FIG. 2A;

[0038] FIG. 2D is a section through line B-B of FIG. 2B;

[0039] FIG. 2E is a lower view of the locking pin of FIG. 2A;

[0040] FIG. 2F is a sectional view through line D-D of FIG. 2E;

[0041] FIG. 3A is a side view of the locking pin and leash assembly according to an embodiment of the present invention;

[0042] FIG. 3B is an isometric view of the locking pin assembly of FIG. 3A;

[0043] FIG. 3C is a sectional view through line A-A of FIG. 3A;

[0044] FIG. 3D is a sectional view through line B-B of FIG. 3A;

[0045] FIG. 3E is a top view of the locking pin with wire of FIG. 3A;

[0046] FIG. 3F is a perspective view of the ferrule of the locking pin and wire of FIG. 3A;

[0047] FIG. 4A is a side view of a shoring support structure provided with a locking pin and wire of FIGS. 2A to 3F;

[0048] FIG. 4B is a partial sectional view through line A-A of FIG. 4A; and

[0049] FIG. 4C is an expanded view of region B shown in FIG. 4B.

DETAILED DESCRIPTION OF THE INVENTION

[0050] The present invention provides an improved locking pin that may be used to lock any type of extendable structure requiring relative linear movement or loading effected by a driven rotating collar.

[0051] In the illustrated examples, the extendable structure is a shoring support structure for use during building work that may be more quickly and easily installed and removed by the user than entirely manual installation of the structures. The shoring support structure may be used in the conventional manner of a standard acrow prop or may be powered by a drill or impact driver, equipment that is normally readily available where building work is being undertaken.

[0052] Referring to FIGS. 1A to IC of the accompanying drawings, one example of a shoring support structure 3 according to the prior art is illustrated. The structure has a pair of telescopically extendable cylindrical tubes of galvanised steel, comprising an inner tube 4 and an outer tube 2. The free end of the inner tube is provided with a head plate 6 and the free end of the outer tube is provided with a base plate 6. The inner tube 4 is provided with a series of spaced apart pairs of opposing transverse holes 14 and the outer tube is provided with a threaded region 22 in an upper region of the tube which includes two opposing longitudinal slots 16. Gross adjustment of the height of the support structure is achieved by sliding the inner tube out of the outer tube so that the tubes almost fill the gap, within which supporting will be performed, and then a pin 24 in the form of a small cylindrical rod is placed through the most appropriate holes 14 and slot 16 in the tubes. The pin sits on a collar 8 threaded onto the outer tube 2 and the collar may be raised and lowered by rotating it on thread 22 to cause the inner tube to rise and fall to provide fine adjustment of the support structure. Different ranges of adjustment can be achieved by fitting the pin in different holes 14 in the inner tube 4. The collar 8 is adapted to include a driven member in the form of a bevel gear 30 on its upper surface whereby the pin 24 that is placed through the holes of the inner tube serves as a shaft for connection to, or support of, a driving member or pinion gear 40 having means for engagement with an actuator (not shown). The pinion gear 40 is provided with a flange 42 to maintain close contact between the gears.

[0053] A manual actuator may be used to turn the shaft and cause rotation of the collar via the pinion and bevel gear, such as a T-handle or right-angled square drive but, more advantageously, a powered actuator is used to operate the support structure, such as a drill or impact driver. Thus, the support structure may be installed in a conventional manner or its installation may be powered by an existing power tool, enabling one person to fix the structure in position quickly and easily.

[0054] Preferably, the gears are provided with an inclined face so that pushing the shaft axially inwards brings the bevel gear 30 and pinion gear 40 into closer contact.

[0055] It is to be appreciated that the pinion 40 may be entirely removable from the support structure such that this part may be provided as a tool for use on the installation of multiple support structures. Additionally, the gears may be sized such that they are only in partial contact and can be driven in further over time. This will increase the longevity of the structure because wear will occur in areas such as the holes, gears and pins. The act of pushing the driving member inwards will tend to keep the gears in contact but the structure could be adapted further to provide means to maintain the shaft in an appropriate axial position, such as by shaping the holes of the inner tube.

[0056] The afore-mentioned arrangement is fit for purpose but the use of a standard acrow prop pin to provide a shaft for the pinion gear is not ideal, primarily because the standard pin is not secured sufficiently within the tube. The present invention provides an improved locking pin for this purpose. FIGS. 2A to 2F illustrate one embodiment of a locking pin 240, shown without a securing wire fitted to it. The main body of the locking pin 240 forms a shaft 242, the length a of which is around 120 mm with a diameter b of around 16 mm, albeit the shaft is not limited to this size. The ends of the shaft are rounded and two protrusions 244 and 248 extend approximately at right angles to the main shaft. The first protrusion 244 extends from an intended lower surface of the shaft and has an inner wall facing towards the centre of the shaft and an opposing outer wall, the inner and outer walls defining opposing side walls. The inner and outer walls extend substantially perpendicularly to the longitudinal axis z (see FIG. 2F) of the shaft 242 but the inner facing wall 246 (see FIG. 2B) is curved to substantially correspond with the curvature of an inner tube 4 and the outer facing wall is curved to substantially correspond with the curvature of an outer tube 2 of a shoring structure (see FIGS. 4B and 4C). The inner and outer facing walls of the first protrusion 244 extend across the whole of the underside of the shaft, i.e., at the point where it meets the shaft the protrusion has a width corresponding substantially to the diameter of the shaft but has a slight tapering a of around 5 degrees (see FIG. 2C). However, each side wall of the protrusion (see FIG. 2B) tapers to an apex at the end of the protrusion. For example, in the illustrated embodiment the apex have a width g of 3.1 mm (see FIG. 2E).

[0057] It is to be appreciated that while it is preferred for the inner facing wall of the first protrusion to be curved to substantially correspond with the curvature of an inner tube and/or the outer facing wall is curved to substantially correspond with the curvature of an outer tube, these curvatures of the inner and outer faces of the projection are not essential as long as the projection fits between the outside diameter of the inner tube and the inside of the thread of the collar (unless a counter bore is added to allow the outer face to move outwards).

[0058] The second protrusion 248 extends substantially perpendicularly from an intended upper surface of the shaft 242, the protrusion being spaced laterally from the first protrusion 244 towards an outer end of the shaft. The second protrusion forms a box-like structure having four sides extending upwardly from the shaft. The width of each side is slightly less than the diameter of the shaft and again the protrusion has a slight tapering towards its free end (for example a tapering a of around 5 degrees). Additionally, the protrusion 248 has a recess 245 through its centre (discussed in further detail in relation to FIGS. 3A to 3F below). The second protrusion is slightly longer than the first protrusion, with the second protrusion having a length c of around 18 mm and the first protrusion having a length d of around 14 mm (see FIG. 2C). The arc of the shaft is intended to fit within the paired holes of the inner tube (see 4 in FIG. 1C). In this embodiment the arc is around 16 mm.

[0059] FIGS. 2D and 2F show further details of the preferred dimensions of the locking pin according to a preferred embodiment of the present invention. These dimensions are dictated by a particular size of acrow prop in relation to which the locking pin is used. However, it is to be appreciated that these dimensions could be altered to fit acrow prop structures of different sizes. FIG. 2D illustrates a cross-section through the shaft 242 of the pin. An optional draft angle a of around 5 degrees may be applied to the top and bottom of the cylindrical profile to allow the part to be created using a forging operation.

[0060] FIG. 2F more clearly illustrates the outer positioning of the second protrusion 248 relative to the first protrusion. In this respect. The inner facing wall of the second protrusion commences at around a length j from the end of the shaft that contacts an actuator, j being around 90.4 mm in contrast to the inner facing surface of the first protrusion 244 being at a distance h of around 84.4 mm from the end of the shaft that contacts an actuator. The outer facing wall of the second protrusion is a length k of around 20.4 from a non-contact end of the shaft, with the outer facing wall of the first protrusion being at a length i of around 32.0 mm from the non-contact end of the shaft 242. Each tapered contact end of the shaft is also shown as providing angle for mating with a central bore of a pinion gear.

[0061] FIGS. 3A to 3F illustrate a locking pin according to the invention provided with a safety wire or leash 250. In the illustrated embodiment a PVC coated wire is provided for the leash but other materials may be used. The second protrusion 248 is able to receive the leash 250 within the recess 245 and the leash can be secured within the protrusion by cold forming, pointing upwardly away from the shaft 242, as shown in FIGS. 3A and 3B. The leash is also provided with a loop 252 spaced apart from the shaft, ideally being at a distance x of at least 110 mm from the top of the protrusion 248 (see FIG. 3A). The loop is formed by the provision of a ferrule 254 which is cold formed onto the junction of the loop of the leash. Any suitable material may be provided for the ferrule that may be deformed around the leash but in a preferred embodiment the ferrule is formed from aluminium.

[0062] As shown in FIG. 3A, distance y between the apex of the first protrusion and the top of the second protrusion is about 32 mm. FIG. 3C shows further detail regarding the fixing of the leash to the protrusion 248 of the locking pin 240. To clamp the wire leash 250 in place a mechanical pressing operation is used to deform the protrusion 248 while in a cold condition (cold forming). The deformation could be applied to any side of the protrusion. In this embodiment it is shown to occur over length p and to a maximum depth o from the centre of recess 245. The PVC coating is stripped from the steel wire to ensure a high clamping force when recess 245 is deformed. A small gap between end of PVC coating and top of the protrusion is expected and denoted by distance q. Again, the dimensions provided for the pin and leash are illustrative and it is to be appreciated that they could be altered dependent upon the component sizes of the shoring structure support.

[0063] The leash envelops an arc r (see FIG. 3E) that is greater than the arc of the outer tube (2 in FIG. 1C). This enables it to be secured to the outer tube preventing loss/separation.

[0064] The ferrule is crimped over the end of the wire with an offset s that ensures the end of the wire does not protrude, preventing it from fraying and being a hazard.

[0065] FIGS. 4A to 4C illustrate the locking pin of FIGS. 2A to 3F in use. A shoring structure similar to that shown in FIGS. 1A to IC is shown fitted with a locking pin 240 of the invention. For the sake of simplicity, identical features already discussed in relation to FIGS. 1 to 3F are given the same reference numerals. The structure comprises an inner tube 4, an outer tube 2 having end plates 6. The inner tube 4 is provided with a series of spaced apart pairs of opposing transverse holes 14 and the outer tube is provided with a threaded region 22 in an upper region of the tube which includes two opposing longitudinal slots 16. A collar 8 is threaded onto the outer tube 2, the collar having a bevel gear 30 on its upper surface. Gross adjustment of the height of the support structure is achieved by sliding the inner tube out of the outer tube so that the tubes almost fill the gap, within which supporting will be performed, and then a locking pin 240 according to the invention is placed through the most appropriate holes 14 and slot 16 in the tubes. As most clearly demonstrated in FIGS. 4B and 4C, the shaft 242 of the pin lies above the bevel gear 30 of the collar 8 and the first protrusion 244 locates in the slot of the outer tube and is wedged between the collar and inner tube 4. This prevents axial movement of the pin when it is connected to a driving member or pinion gear 40 having means for engagement with an actuator (not shown). The pin 240 sits on the collar and mates with the pinion gear which may be driven by a handle or powered actuator, the pinion gear imparting motion to the bevel gear of the collar to cause the inner tube 4 to rise and fall to provide fine adjustment of the support structure. Different ranges of adjustment can be achieved by fitting the pin in different holes 14 in the inner tube 4. The leash 250 is provided around the inner tube 4. As shown most clearly in FIG. 4B, the attachment of the leash 250 at the second protrusion 248 of the locking pin laterally from the first protrusion and upwardly from the collar ensures that the leash does not get snagged by the gear teeth during installation of the prop.

[0066] Thus, the locking pin and leash according to the present invention allows for the pin to be securely held between the collar and inner tube during operation of the gears to adjust the height of the prop. This also provides for less wear and tear of the component parts. Furthermore, the cold formation of the leash extending upwardly away from the collar prevents damage to the leash and snagging of the leash that would hinder operation of the device.

[0067] It is clear that the shoring support structure and locking pin of the present invention may be provided as a completely new product or the component parts, in particular the collar with a bevel gear and pinion with locking pin, may be provided separately to allow retrospective fitting to existing acrow props to enable these devices to be powered by an impact driver or drill.

[0068] While the illustrated embodiments are in relation to a vertical shoring support structure with flat base and head plates, it is to be appreciated that the support may be used in alternative orientations with different types of fixings, such as U-shaped head plates or L-shaped head plates. The plates may also be adjustable, for example, to enable them to be fixed at an angle depending upon the structure supported. As with conventional acrow props, the structures could be provided in a range of sizes to fit different sizes of gaps. All the component parts may be provided as a kit.

[0069] Further modifications to a locking pin for a shoring support structure may be made without departing from the principles embodied in the examples described and illustrated herein.