GB2084641A

GB2084641A - Scaffolding coupling

Info

Publication number: GB2084641A
Application number: GB8032050A
Authority: GB
Original assignee: Burton Delingpole and Co Ltd
Current assignee: Burton Delingpole and Co Ltd
Priority date: 1980-10-04
Filing date: 1980-10-04
Publication date: 1982-04-15
Also published as: GB2084641B

Abstract

A coupling for use in the assembly of scaffolding comprises a body part (12), and a clamping jaw (13) pivotally mounted on the body part by means of a pivot (15). The coupling comprises a T-bolt (20), the head (21) of which is adapted to be seated within an outwardly facing arcuate recess (22) of the body part, with a two-start threaded shank (23) adapted to be inserted within a bifurcated part (17) of the clamping jaw. By tightening a corresponding two-start threaded nut (24) on the shank (23), the clamping jaw and the body part may be drawn together around a scaffold tube. <IMAGE>

Description

SPECIFICATION Improved scaffolding coupling This invention relates to a coupling which is used in the assembling of scaffolding and which includes at least one bolt and co-operating nut to perform a clamping function in the coupling.

The type of coupling to which the invention relates is that in which the bolt is connected pivotally by means of its head to a body part of the coupling, and has its threaded shank passing through an opening at one end of an arcuate-shaped clamping jaw, the other end of which is pivotally connected to the body part, the arrangement being that, with the shank of the bolt disengaged from the clamping jaw, this can be swung to an open position away from the body part so that a scaffolding tube can be accommodated between the clamping jaw and the body part, the jaw being then swung back to the closed position and the shank of the bolt passed through the said opening at one end of the clamping jaw so that when the nut is tightened up on the bolt, the clamping jaw will be drawn towards the body part and the scaffolding tube is securely clamped between the clamping jaw and the body part.

In the case of connecting two scaffolding tubes together, such as a horizontal tube to an upright tube, the coupling would include two clamping jaws, each with its associated bolt and nut fastening.

Hereinafter a scaffolding coupling having the above features is referred to as being a scaffolding coupling of the type specified.

When scaffolding is being erected, a major part of the time is taken up in the operation of tightening the nuts on the clamping bolts of the couplings. The initial tightening of each nut is usually performed by hand alone with the final tightening, to achieve the desired clamping force, being performed with the aid of a wrench and there is a call for some means to lessen the time of these operations.

One proposal to achieve this has involved the provision of a non-standard thread formed on the clamping bolt and in the associated nut, with a smaller number of threads per unit length. However, in practice this can result in the nut and bolt fastening being weaker than one which has a standard thread on the bolt and in the nut because the non-standard thread form has less surface area of thread engagement, and this can give rise to stripping of the thread under excess load conditions.

With the conventional nut and bolt fastening having standard thread form and thread pitch, the excess load on the fastening cannot result in stripping of the thread because, before this can happen, the bolt will fail in the normal way of a bar under tension with the shank first stretching (and thus giving an indication of overload) before breakage occurs. With the aforesaid proposal using a nonstandard thread form and pitch, the thread can be stripped under overload without warning and at a load value less than that capable of being sustained by the conventional form of bolt and nut fastening.

The object of this invention is to provide an improved scaffolding coupling of the type specified having a bolt and nut fastening capable of being operated for tightening and loosening more rapidly than the conventional form of fastening but without reduction in the maximum load capacity of the fastening.

According to the invention we provide a scaffold coupling of the type specified wherein the or each clamping bolt has a two-start thread of standard thread form and the or each associated nut has a corresponding thread form.

The invention is hereinafter described and illustrated in the accompanying drawing by way of example with reference to a particular form of scaffolding having a bolt and nut fastening embodying the present invention.

The example of scaffolding coupling shown in the accompanying drawings is one which is used for connecting two scaffolding tubes 10 and 11 with their axes in mutually perpendicular relationship and the coupling comprises a central body part 12 which has two arcuate seatings, the axes of which are mutually perpendicular, and which embrace parts of the external surfaces of the tubes 10 and 11 when the coupling is applied. The body part 12 has two clamping jaws pivotally connected thereto and hereinafter only one such clamping jaw is referred to and described, the other jaw being identical.

Referring to the right-hand half of the drawing, the clamping jaw 13 is of arcuate form and at one end has á pair of spaced apart lugs 14 by means of which the jaw 13 is pivotally connected by a pivot pin 15 to the end 16 of body part 12. At its other end, the clamping jaw 13 is bifurcated to provide two spaced apart lugs 17 between which is an opening in which is engaged the shank of the clamping bolt as hereinafter described.

At the end remote from the part 16, the body part 12 has a projecting lug 18 provided with an aperture 19 through which the shank of the clamping bolt is passed. The clamping bolt is of T-form having a shank 20 with a T-shaped head 21 at one end and when the shank 20 is passed through the aperture 19, the head 21 rests in the recess 22 provided by the form of the lug 18.

In accordance with the invention the threaded part of the clamping bolt is provided with a two-start thread as shown at 23 and there is a co-operating nut 24 and associated clamping washer 25 for tightening uponthetwo-startthread 23 to draw the jaw 13 towards the body part and clamp the tube 11 securely between the body part 12 and the interior surface of the jaw 13. By virtue of the two-start thread, the initial tightening down of the nut 24 by hand can be carried out more rapidly than is the case of a standard single-startthread form as used hitherto.

1. A coupling for use in the assembly of scaffolding and comprising: (a) a body part; (b) a clamping jaw mounted on the body part for movement relative thereto between an open position in which the coupling may be removed from or positioned around a scaffold tube, and a closed position in which the body part and the clamping jaw closely embrace the scaffold tube around which the

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improved scaffolding coupling This invention relates to a coupling which is used in the assembling of scaffolding and which includes at least one bolt and co-operating nut to perform a clamping function in the coupling. The type of coupling to which the invention relates is that in which the bolt is connected pivotally by means of its head to a body part of the coupling, and has its threaded shank passing through an opening at one end of an arcuate-shaped clamping jaw, the other end of which is pivotally connected to the body part, the arrangement being that, with the shank of the bolt disengaged from the clamping jaw, this can be swung to an open position away from the body part so that a scaffolding tube can be accommodated between the clamping jaw and the body part, the jaw being then swung back to the closed position and the shank of the bolt passed through the said opening at one end of the clamping jaw so that when the nut is tightened up on the bolt, the clamping jaw will be drawn towards the body part and the scaffolding tube is securely clamped between the clamping jaw and the body part. In the case of connecting two scaffolding tubes together, such as a horizontal tube to an upright tube, the coupling would include two clamping jaws, each with its associated bolt and nut fastening. Hereinafter a scaffolding coupling having the above features is referred to as being a scaffolding coupling of the type specified. When scaffolding is being erected, a major part of the time is taken up in the operation of tightening the nuts on the clamping bolts of the couplings. The initial tightening of each nut is usually performed by hand alone with the final tightening, to achieve the desired clamping force, being performed with the aid of a wrench and there is a call for some means to lessen the time of these operations. One proposal to achieve this has involved the provision of a non-standard thread formed on the clamping bolt and in the associated nut, with a smaller number of threads per unit length. However, in practice this can result in the nut and bolt fastening being weaker than one which has a standard thread on the bolt and in the nut because the non-standard thread form has less surface area of thread engagement, and this can give rise to stripping of the thread under excess load conditions. With the conventional nut and bolt fastening having standard thread form and thread pitch, the excess load on the fastening cannot result in stripping of the thread because, before this can happen, the bolt will fail in the normal way of a bar under tension with the shank first stretching (and thus giving an indication of overload) before breakage occurs. With the aforesaid proposal using a nonstandard thread form and pitch, the thread can be stripped under overload without warning and at a load value less than that capable of being sustained by the conventional form of bolt and nut fastening. The object of this invention is to provide an improved scaffolding coupling of the type specified having a bolt and nut fastening capable of being operated for tightening and loosening more rapidly than the conventional form of fastening but without reduction in the maximum load capacity of the fastening. According to the invention we provide a scaffold coupling of the type specified wherein the or each clamping bolt has a two-start thread of standard thread form and the or each associated nut has a corresponding thread form. The invention is hereinafter described and illustrated in the accompanying drawing by way of example with reference to a particular form of scaffolding having a bolt and nut fastening embodying the present invention. The example of scaffolding coupling shown in the accompanying drawings is one which is used for connecting two scaffolding tubes 10 and 11 with their axes in mutually perpendicular relationship and the coupling comprises a central body part 12 which has two arcuate seatings, the axes of which are mutually perpendicular, and which embrace parts of the external surfaces of the tubes 10 and 11 when the coupling is applied. The body part 12 has two clamping jaws pivotally connected thereto and hereinafter only one such clamping jaw is referred to and described, the other jaw being identical. Referring to the right-hand half of the drawing, the clamping jaw 13 is of arcuate form and at one end has á pair of spaced apart lugs 14 by means of which the jaw 13 is pivotally connected by a pivot pin 15 to the end 16 of body part 12. At its other end, the clamping jaw 13 is bifurcated to provide two spaced apart lugs 17 between which is an opening in which is engaged the shank of the clamping bolt as hereinafter described. At the end remote from the part 16, the body part 12 has a projecting lug 18 provided with an aperture 19 through which the shank of the clamping bolt is passed. The clamping bolt is of T-form having a shank 20 with a T-shaped head 21 at one end and when the shank 20 is passed through the aperture 19, the head 21 rests in the recess 22 provided by the form of the lug 18. In accordance with the invention the threaded part of the clamping bolt is provided with a two-start thread as shown at 23 and there is a co-operating nut 24 and associated clamping washer 25 for tightening uponthetwo-startthread 23 to draw the jaw 13 towards the body part and clamp the tube 11 securely between the body part 12 and the interior surface of the jaw 13. By virtue of the two-start thread, the initial tightening down of the nut 24 by hand can be carried out more rapidly than is the case of a standard single-startthread form as used hitherto. CLAIMS

1. A coupling for use in the assembly of scaffolding and comprising: (a) a body part; (b) a clamping jaw mounted on the body part for movement relative thereto between an open position in which the coupling may be removed from or positioned around a scaffold tube, and a closed position in which the body part and the clamping jaw closely embrace the scaffold tube around which the coupling has been positioned and (c) screw-threaded clamping means which may be operated to draw the clamping jaw and the body part together securely to clamp the coupling around a scaffold tube, wherein the screw-threaded means comprises a multi-start thread.

2. Acoupling according to Claim 1 wherein the body part and the clamping jaw are pivotally mounted together at end portions thereof and the screw-threaded means is operative between opposite end portions thereof.

3. A coupling according to one of Claims 1 and 2 wherein the screw-threaded means is adapted for pivotal connection to the body part.

4. Acoupling according to any one of the preceding claims wherein the screw-threaded means comprises a T-bolt and a nut adapted for screw-threaded engagement with the shank of the T-bolt

5. A coupling according to Claim 4 wherein the head of the T-bolt is adapted to be seated within an outwardly-facing, arcuate recess of the body part.

6. A coupling according to one of Claims 4 and 5 wherein the clamping jaw comprises a bifurcated end portion, the nut being adapted to engage an outwardly-facing surface of said bifurcated portion.

7. Ascaffold coupling ofthetype specified wherein the or each clamping bolt has a two-start thread of standard thread form and the or each associated nut has a corresponding thread form.

8. A coupling for use in the assembly of scaffolding, constructed and arranged substantially as hereinbefore described with reference to the accompanying drawing.

9. Any novel feature or novel combination of features hereinbefore described and/or shown in the accompanying drawing.