GB2090367A - Scaffolding couplings - Google Patents

Abstract

In builder's scaffolding, the invention substitutes steel pressing for other forms of fabrication in making a spigot (4) for attachment to a cross-member (1) intended for coupling to an upright by insertion of the spigot into a loop-type socket (3) on the upright (2), yielding economic advantages in the manufacture of the scaffolding. In a preferred embodiment, the spigot (4) is a channel of U-section, the free edges of the channel (corresponding to the tips of the limbs of the U in cross-section) being profiled to match the exterior of the upright (2) to permit a tight fit on assembly with the aid of a wedge (5) inserted into the socket (3) and hammered home. <IMAGE>

Description

SPECIFICATION Improvements in or relating to builder's scaffolding This invention relates to builder's scaffolding of the kind which comprises upright members (hereinafter called standards), horizontal ledger and transom members (hereinafter called crossmembers) and coupling means for connecting cross-members to standards. It relates in particular to builder's scaffolding wherein the coupling means includes a loop-type socket fixed to and projecting laterally from a standard, and a spigot depending from an end of a cross-member and receivable in the socket. The standards and cross-members are commonly constructed from cylindrical mild steel tubing; but they may have any of various other crosssections, such as square or rectangular, L-section, T-section or H-section. Such scaffolding is hereinaf terdesignated scaffolding of the type described.

In scaffolding of the type described, it is conventional to form the spigot by the process of malleable casting or the process of drop forging, both of which are expensive. It is an object of this invention to provide builder's scaffolding utilising a more economical manufacturing technique.

The invention therefore provides builder's scaffolding of the type described, wherein the spigot comprises a steel pressing which is welded on to the end of the cross-member or an extension thereof.

Preferably the spigot is pressed from mild steel plate.

Advantageously the spigot has a face adapted to bear against the standarc. Advantageously also, the coupling means additionally comprises a wedge adapted for insertion into the socket to secure the spigot to the standard, thereby securing the entire cross-memberto the standard.

In a particular and advantageous embodiment of the invention, the spigot is a channel member of U-section, and the free edges thereof which appear in cross-section as the tips of the limbs of the U are profiled to match the exterior of the standard. Preferably this U-section channel tapers from the bottom to the top of the spigot in the orientation of use, so that the back or neck of the U, along the length of the spigot in side elevation in use, is inclined downwardly away from the standard, so as to present a sloping surface to cooperate with a wedge inserted from above. It is also preferred that the spigot be welded to a pair of parallel cheeks, themselves welded to the end of the cross-member, and defining between them a slot for the accommodation of the wedge. The wedge may be deformed locally, as by dimples, to secure it loosely but non-releasably in the slot.

The invention will be appreciated in greater detail from the following description of a particular and preferred embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which FIG. 1 is a perspective view of a detail of a builder's scaffolding, showing a cross-member coupled to a standard; FIG. 2 is a side elevation of the scaffolding detail of Fig. 1; FIG. 3 is a perspective view of the wedge used in the scaffolding detail of Figs. 1 and 2; FIG. 4 is a perspective view of an end of the cross-member shown in Figs. 1 and 2; and FIG. 5 is a perspective view of an intermediate portion of the standard shown in Figs. 1 and 2.

Referring now to the drawings, a builder's scaffolding comprises a generally rectangular assembly of cross-members 1, coupied to standards 2 by coupling means comprising, in each case, a socket 3, a spigot 4 and a wedges.

Each cross-member 1 is of straight tubular steel cutt off at both ends perpendicularly to its cylindrical axis. To each end a pair of angle brackets 6 is welded in a manner resembling a pair of book-ends in use, defining between their respective parallel projecting cheeks 7 a slot 8 to accommodate the wedge 5. The spigot 4 is a steel pressing of U-section channel form; it tapers from a wide lower portion 4a to a narrow upper portion 4b but the tapering is confined to the sides of the channel, whose radius of curvature is constant. The edges 9 of the channel are machined to lie in a curved cylindrical surface of radius equal to the external radius of the standard 2.

The cylindrical axis ofthis surface and that ofthe channel lie in a plane parallelto the cheeks 7.

The spigot 4 is welded to the cheeks 7 with its concave aspect directed away from the crossmember 1,the edges 9 being oriented perpendicu larly to the cylindrical axis of the cross-member 1.

Thus the convex aspect 10 of the spigot, seen in side elevation in use, is at a small angle to the perpendicular, enabling it cooperate with a sloping edge 5a of the wedges.

The socket 3 is a simple U-channel or loop of mild steel with parallel sides 3a terminating in spaced apart feet 3b which are welded to the standard 2 along lines parallel to the cylindrical axis of said standard. The base of the U-channel of this socket 3 is likewise parallel to said axis, i.e., is vertical in use.

Thus in use of the builder's scaffolding according to the invention, the coupling means, as best seen in Figs. 1 and 2, are assembled by offering the crossmember 1 to the standard 2 with the spigot 4 downwardly directed, inserting the spigot 4 into the socket 3 from above, inserting the wedge 5 into the slot 8 from above, and striking the top of the wedge 5 with a hammer to force the spigot 4 against the outer surface of the standard 2 by reaction of the wedge against the inner aspect or base ofthe U-channel of the socket 3.

The chief novel feature of the invention, as indicated above, is the use of steel pressing forthe fabri- cation of the spigot. In embodiments having parallel cheeks defining a slot for the wedge, and supporting the spigot, the cheeks are likewise made from steel pressings. In conventional builder's scaffolding (of the type described) however, the spigot and associ ated structures are commonly fashioned as a unit by malleable casting or drop forging.

When made by malleable casting, the unit is cast from molten iron in a first stage, and cooled and subjected to heat and chemical treatment in a second stage. For a standard size unit the estimated unit production cost is lR0.65 and the unit weighs about 340 grms. (Costs quoted are at late 1981 levels).

When made by drop forging, the unit begins its existence as a mild steel blank. This is raised to a high temperature and then subjected to the known drop forging process. The unit produced is commonly drilled and fixed to a cross-member by riveting or bolting. The estimated unit cost is lR0.60 and the unit weighs about 310 grms (for a standard size unit).

A unit of standard size produced according to the invention on the other hand, and before attachment to a cross-member, has a manufacturing cost of only It0.25, weighs about 114 grams, and has not involved the application of any heat. Its strength and reliability in use, however, are comparable to those ofthe above-mentioned prior art units.

It was found possible to equip a cross-member with a cheek-and-spigot assembly 7,4 at an exfactory cost of It0.32 at 1980 prices, including the cost of material (5p), the pressing operation (7p) to produce the spigot form, and the machining and welding (20p) necessary to form the finished assembly. The most competitive similar assembly of the prior art at that time hadan ex-factory cost of IR1.05, much of which was accounted for by the cost of casting (50p) and the subsequent cleaning and fettling (35p).

The economic advantages of builder's scaffolding constructed according to the invention are thus apparent.

Claims (11)

1. Builder's scaffolding which comprises standards, cross-members and coupling means therefor and wherein the coupling means includes a looptype socket fixed to and projecting laterally from a standard, and a spigot depending from one end of a cross-member and receivable in the socket, characterised in that the spigot comprises a steel pressing which is welded onto the cross-member or an extension thereof.

2. Builder's scaffolding according to claim 1 wherein the spigot is pressed from mild steel plate.

3. Builder's scaffolding according to claim 1 or 2 wherein the spigot has a face adapted to bear against the standard.

4. Builder's scaffolding according to claim 2 or 3 wherein the coupling means additionally comprises a wedge adapted for insertion into the socket to sec urethespigottothe standard.

5. Builder's scaffolding according to claim 3 or 4 wherein the spigot is a channel of U-section, and the free edges thereof which appear in cross-section as the tips of the limbs of the U are profiled to match the extenor otthe standard.

6. Builder's scaffolding according to claim 5 wherein the channel tapers from the bottom to the top of the spigot in the orientation of use, so that the back or neck of the U, along the length of the spigot in side elevation in use, is inclined downwardly away from the standard, so as to present a sloping surface to cooperate with a wedge inserted from above.

7. Builder's scaffolding according to any of claims 4 to 6, wherein the spigot is welded to a pair of parallel cheeks, themselves welded to the end of the cross-member, and defining between them a slot for the accommodation of the wedge.

8. Builder's scaffolding according to claim 1, substantially as herein described.

9. 8 spigot which comprises a steel pressing and is adapted for use in the fabrication of builder's scaffolding according to claim 1.

10. Builder's scaffolding substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

11. Any novel feature or combination of features disclosed herein.