GB2087465A

GB2087465A - Pin Assembly for Adjustable Scaffolding

Info

Publication number: GB2087465A
Application number: GB8104779A
Authority: GB
Original assignee: LOMBARD ENGINEERS Ltd
Current assignee: LOMBARD ENGINEERS Ltd
Priority date: 1980-11-15
Filing date: 1981-02-16
Publication date: 1982-05-26
Also published as: GB2087465B

Abstract

A pin assembly for adjustable scaffolding of a type in which relative axial positions of a pair of telescoping members (12 and 14) are determined at least partly by a transverse pin (11) passing through aligned apertures (19) in the inner telescoping member and (22, 23) in the outer telescoping member (12). The aperture (23) is larger than the aperture (22), which is surrounded by a depression (26) on the inner surface of the member (12). The pin (11) is cold headed at one end to form a small head (24) which can be held captive by the small aperture (22) and which lies within the depression (26). The other end of the pin (11) is formed with an enlarged head (25) after assembly so that the pin is totally captive to the outer telescoping member. In the example described, the pin forms part of a unitary head or base jack (13). <IMAGE>

Description

SPECIFICATION Pin Assembly for Adjustable Scaffolding This invention relates to a pin assembly for adjustable scaffolding.

The term "adjustable scaffolding" as used in this Specification is intended to mean any form of scaffolding in which the relative axial positions of a pair of telescoping members are determined wholly or partly by the use of a transverse pin passing through apertures or otherwise abutting the members.

For example, at the foot of an upright scaffolding stanchion a base jack may be provided for adjusting the level of the scaffold tube relative to a substrate surface. A similar form of jack, known as a head jack, can be provided at the upper end of the scaffold stanchion in order to adjust the level of formwork or a platform supported by the scaffolding.

Other forms of adjustable scaffolding include builders' trestles used for supporting platforms at relatively low levels and props of the type which may be used for temporary support to lintels, ceilings or the like during building or alteration work.

For convenience of description, the invention will be described in relation to a base jack but it will be appreciated that the principles of the invention are equally applicable to other forms of adjustable scaffolding.

One of the problems at present encountered in the use of adjustable scaffolding is that the pin needed for setting the correct height for the scaffolding can become lost, damaged or covered with such materiais as concrete or mortar which may make it difficult to use. Although the problem of loss of scaffold pins has been tackled in the past by chaining them to a lug welded onto, or otherwise formed on a scaffold element adjacent the position where the pin is to be used, this is by no means satisfactory since the chain can break or become corroded, it is necessary to have a lug or the like welded externally to the scaffold element and because it is difficult to handle a pin attached by a relatively bulky chain to the scaffolding element.

It is an object of the present invention to provide a pin assembly for adjustable scaffolding as herein defined which overcomes or reduces these disadvantages.

It is a further object of the invention to provide a new or improved form of scaffold jack incorporating such a pin assembly.

According to the invention, there is provided a pin assembly for adjustable scaffolding as herein defined, the assembly comprising a pin and an outer telescoping member of the adjustable scaffolding, said member having a pair of diametrically oppositely disposed apertures to receive the pin, one of said apertures being small in size than the other, said one aperture being surrounded by a depression provided in the inner surface of the outer telescoping member and the pin being headed at both ends, one end of the pin having a head capable of passing through said other aperture, but not said one aperture, and adapted to be received in the depression surrounding said one aperture without substantially projecting therefrom.

The other end of the pin may be headed by a deforming operation comprising pressing or forging at a pair of diametrically opposed positions to cause the metal to bulge outwardly between these positions, the operation being carried out after assembly of the pin with the telescoping member.

Said one end of the pin may be headed before assembly of the pin with the outer telescoping member, by performing an axial cold heading operation thereon.

The outer telescoping member may form an externally screw-threaded part of a jack, adapted to receive a spigot of a base or head plate having axially spaced transverse apertures to receive the pin.

Alternatively, the outer telescoping member may comprise an outer tube of an adjustable prop or an outer tube of a trestle and, in the former case, may include external screw threads.

According to a further aspect of the invention there is provided an adjustablr scaffolding jack comprising an inner telescoping member comprising a spigot having a base plate and a plurality of axially spaced transverse apertures adapted to receive a pin; an outer telescoping member comprising an externally threaded sleeve having a pair of diametrically oppositely disposed apertures adapted to receive the pin, the spigot having one or more outwardly projecting nibs retaining the sleeve captive on the spigot; and a pin assembly according to the first aspect of the invention.

The invention will now be described in more detail by way of example only with reference to the accompanying drawings in which Figure 1 is a vertical sectional view of a base jack embodying a pin assembly; Figure 2 is a side elevational view of the pin of Figure 1; Figure 3 is an end elevational view on the arrow 3 of Figure 2; Figure 4 is a detail sectional view illustrating the pin assembly in an alternative condition.

Referring firstly to Figure 1 of the drawings, a pin assembly is generally indicated at 10 and comprises a pin 11 and an outer telescoping member 1 2. In this particular case, the outer telescoping member comprises an externally threaded sleeve forming part of a base jack generally indicated at 13, which additionally comprises an outer sleeve 14. The outer sleeve 14 is formed, in the example shown, as a metal pressing, the upper end being inwardly turned at 1 5 to form an abutment for receiving a scaffold tube 16, shown in dotted outline. The lower end of the outer sleeve 14 is also pressed inwardly at 1 7 to form a collar which is provided with an internal thread, co-operating with the external thread of the member 12. The threads can be cut or rolled.

It will therefore be seen that the outer sleeve 14 can be raised and lowered relative to the member 12 by rotating the parts relative to each other, so that the internal and external threads cooperate.

In use, a base jack to support a scaffold tube 1 6 is roughly positioned for height from a base plate (not shown) which carries a rigid upstanding spigot 18. The spigot 18, which may be hollow or solid, extends upwardly by a certain distance sufficient to bring it into the lower end of the scaffold tube 1 6. It therefore provides lateral location to prevent the scaffold tube 1 6 from being displaced sidewards.

The spigot 18 is provided with pairs of diametrically opposed openings 19, the pairs of openings being regularly spaced axially along the spigot.

One or more outwardly pressed nibs 9 can be formed on the upper end of the spigot 18 after the jack has been slid onto the spigot. The nib or nibs effectively hold the jack captive to the spigot since it cannot pass over the nib at one end or over the base plate (not shown) which is welded to the other end of the spigot The nib 9 has a shallow taper facing the free end of the spigot so as not to obstruct the scaffold tube 16, which can be slid over the spigot to abut the upper end 1 5 of the outer sleeve 14.

The jack is positioned at the chosen pair of openings 19 by means of the pin which passes through the member 12 and through the openings 19 in the spigot. Fine adjustment of the height of the base of the scaffold tube 16 can then be carried out by rotating the sleeve 14 relative to the member 12, for which purpose an external lug 20 is provided on the sleeve 14.

The pin 11 has a head at each end. A small head 21 is formed prior to assembly by means of a cold heading operating, involving one or more impacts being exerted axially on the end of the pin.

It will be seen that the member 12 has a pair of diametrically opposed apertures, one aperture 22 being smaller than the other aperture 23. The small head 21 of the pin can pass through the larger aperture 23 but not through the small aperture 22 of the member 12.

The small aperture 22 of the member 12 is surrounded on the inner surface of the member by a depression 26 which may be formed, for example, by a plunging operation such that the wail of the member 12 is distorted outwardly around the aperture 22. The depression is sized so that the small head 21 on the pin can rest within the depression without substantially projecting inwardly into the bore of the member 12. Figure 4 of the drawings shows a detail of the pin in this position relative to the member 12.

As referred to above, the head 21 is provided on the pin before it is assembled with the member 12. A large head 25 is provided on the other end of the pin after assembly with the member 12, thereby making the pin 11 captive to the member 12.

Referring to Figures 2 and 3 ofthe drawings, it will be seen that the head 12 is formed by a pressing or forging operation at two opposed positions of the end of the pin. A pair of flats 26 are thereby provided, and the remaining metal bulges outwardly at 27 to such an extent that the pin cannot then be withdrawn through the small aperture 22 of the member 12.

It will be seen that the pin is therefore rendered captive to the member 12 in such a way that it does not project into the bore of the member 1 2 so that, when the pin is pulled outwardly to the position illustrated in Figure 4, the adjustable scaffolding can be telescoped without the pin fouling the inner telescoping member. In the particular example of the base jack shown, the member 12 can be slid over the spigot to bring it into a position where the apertures 22 and 23 are aligned with the openings 1 9 of the spigot 1 8.

The pin 11 can then be simply pushed through the aligned apertures and openings to the condition shown in Figure 1 of the drawings.

There is no danger of the pin being lost because it is captive to the member 12. It does not form an obstruction to the telescoping movement of the adjustable scaffolding.

No chain is necessary to retain the pin and this eliminates the operations which have to be performed at present to secure both ends of the chain, one to the pin and one to the outer telescoping member. Furthermore, because no lug is needed on the outer telescoping member to hold the pin captive, an additional part and an additional welding operation are avoided.

Because of the absence of any chain, and because the pin is retained in position in the aperture 22 at all times, it is very easy to manipulate the pin to bring it through the aligned openings and apertures of the adjustable scaffolding. This is a particular advantage when it is realised that the use of the apparatus is likely to be carried on in cold or wet weather conditions when handling any small article tends to become difficult.

The only movement which needs to be performed by the pin is an axial sliding movement through aligned openings. This means that any mortar or concrete which may fall on the pin is likely to be scraped off. In contrast, where a chain is provided to hold a captive pin, the chain is always accessible from the outside of the apparatus and concrete or mortar may build up on it, restricting the degree of movement available for manipulating the pin.

Claims

1. A pin assembly for adjustable scaffolding as herein defined, the assembly comprising a pin and an outer telescoping member of the adjustable scaffolding, said member having a pair of diametrically oppositely disposed apertures to receive the pin, one of said apertures being smaller in size than the other, said one aperture being surrounded by a depression provided in the inner surface of the outer telescoping member and the pin being headed at both ends, one end of the pin having a head capable of passing through said other aperture, but not said one aperture, and adapted to be received in the depression surrounding said one aperture without substantially projecting therefrom.

2. A pin assembly according to Claim 1 wherein the other end of the pin is headed by a deforming operation comprising pressing or forging at a pair of diametrically opposed positions to cause the metal to bulge outwardly between these positions, the operation being carried out after assembly of the pin with the telescoping member.

3. A pin assembly according to Claim 1 or Claim 2 wherein said one end of the pin is headed by performing an axial cold heading operation thereon, before assembly of the pin with the outer telescoping member.

4. A pin assembly according to any preceding claim wherein the outer telescoping member forms an externally screw-threaded part of a jack, adapted To receive a spigot of a base or head plate having axially spaced transverse apertures to receive the pin.

5. A pin assembly according to any one of Claims 1 to 3 wherein the outer telescoping member comprises an outer tube of an adjustable prop.

6. A pin assembly according to Claim 5 wherein the outer telescoping member includes external screw threads.

7. A pin assembly according to any one of Claims 1 to 3 wherein the outer telescoping member comprises outer tube of a trestle.

8. A pin assembly for adjustable scaffolding substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

9. An adjustable scaffolding jack comprising an inner telescoping member comprising a spigot having a base plate and a plurality of axially spaced transverse apertures adapted to receive a pin; an outer telescoping member comprising an externally threaded sleeve having a pair of diametrically oppositely disposed apertures adapted to receive the pin, the spigot having one or more outwardly projecting nibs retaining the sleeve captive on the spigot; and a pin assembly according to any one of claims 1 to 4.

10. An adjustable scaffolding jack incorporating a pin assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.