GB2177451A - Fastening for scaffolding strut - Google Patents

Abstract

A scaffolding strut 13 adapted in use to form a diagonal brace being part of a scaffolding structure is an elongate structural element and has adjacent at least one end thereof a spigot 14 extending transversely from the longitudinal axis of the strut. Said spigot being provided with a concentric bore along its longitudinal axis houses the shaft 16 of a rotatable locking member adapted for setting in either operative or inoperative positions for retention and release respectively of the strut. A balance weight 17 is used to maintain the locking member in the aperture position (Fig. 4). <IMAGE>

Description

SPECIFICATION Scaffolding strut This invention relates to a scaffolding strut, particularly, though no exclusively, for use in constructing shoring orfalsework structures.

In GB 1579825 and 1599646 is described a ledger, which in use is disposed horizontally, and which has an end connectorfitting each ledger end; and a strut, which in use is disposed diagonally, to form a brace, and which is provided with a laterally extending mounting pin adjacent each strut end, each end fitting having a pair of additional circular apertures, one or both of which selectively, may receive a mounting pin. It is, of course, desirable, once such a mounting pin has been inserted, and the strut erected, that the mounting pin should not be inadvertently dislodged and accordingly the above-mentioned Patents disclose catch arrangements to preclude inadvertant dislodgement. However, these catch arrangements, comprising a pivotable, spring loaded safety finger carried internally of the strut, are relatively complex in design and hence costly to produce.

According to the present invention, there is provided a scaffolding strut adapted, in use, to form a diagonal brace, the strut being of elongate construction and having, adjacent at least one end thereof, an elongate mounting formation extending transversely with respect to the longitudinal axis of the strut, said mounting formation including a central bore parallel to its longitudinal axis within which bore being housed a rotatable locking chamber adapted for setting in either operative or inoperative positions and having provision for chosen positions to be maintained by gravity.

Said mounting formations referred to as spigots are being provided with circular bearing surfaces for pressure contacts on matching surfaces of receiving formations namely sockets.

The locking formation being part of the rotatable locking means is located at the end of the spigot being in the form of a projection extending transversely from the longitudinal axis of the spigot having a retaining abutment cooperating with the receiving formation.

The locking means further include a rotatable bar extending through a central bore on the longitudinal axis of the spigot. One end of said bar is rigidly connected to a conical head portion which forms the point of the spigot. The head portion carries the aforementioned locking formation over a short portion of its perimeter.

The other end of the bar is rigidly connected to an eccentrically mounted balance weight. If the said bar is allowed to rotate freely it will come to rest under gravitational force when the centre of gravity of the locking means and the axis of the bar are in a vertical plane. This state is referred to as the operative position of the locking means.

The receiving formations include a cylindrical bore and a recess from the cylindrical surface over a short portion of the circumference extending the length of the bore. Said recess having shape and size to allow the passage of the aforementioned projection on the head portion of the spigot.

In the operative position the conical head portion is not in register with the aperture provided by connecting means on the scaffold namely the socket. The spigot cannot be introduced into or removed from the socket. For engagement and disengagement the locking means have to be held in an inoperative position.

In preferred type of construction the bar of the locking means is longer than the length of the spigot. In such arrangement the locking means are slidably mounted for movement parallel with the longitudinaly axis of the spigot. The two extreme positions of such movement correspond to the operative and inoperative positions of the locking means. The arrangement provides for a holding position of the locking means without moving the strut from its assembly.

The invention will be further presented by the use of an example and with reference to accompanying drawings.

Fig. 1 is a longitudinal section of a spigot and socket assembly according to the invention with the locking means in the inoperative position.

Fig. 2 shows section A-A of Fig. 1.

Fig. 3 is a section similar to Fig. 1 but witch locking means in the inoperative position.

Fig. 4 shows elevation B-B of Fig. 3.

Referring now to Figurs 1 to 4 inclusive, there is shown connector provision of a horizontal socket 10 mounted on either a horizontal or a vertical member of a scaffold of the kind described (not shown).

Attachment is indicated by jagged line 11. The socket has a circular aperture opening on both sides. The aperture is extended on one side by a rectangular groove 12. Grooves of other geometric shapes can also be used. The combined aperture has a key-hole appearance.

A brace member inclined at an angle is shown at 13. On the end of the brace there is mounted a transversely projecting spigot 14 engaged in the aperture of the socket. The length of the socket approximately equals the length of the spigot.

The locking means comprise of the head 15, the bar 16 and the balance weight 17. There is a projecting rib 18 on the head which includes an abutment portion 19.

It can be seen that in the inoperative position the locking abutment 19 is located within the groove 12.

The locking means are thus prevented from rotating.

The spigot can be disengaged by sliding out of the socket and there is no need to hold the locking means while this is effected.

In the inoperative position the balance weight is spaced apart from the brace by a distance that exceeds the depth of the enclosed portion of the locking abutment 19 within the groove 12. When the balance weight is moved towards contact with the brace the locking abutment 19 is disengaged from the groove and the locking abutment 19 is disengaged from the groove and the locking means can rotate into the operative position due to gravity bringing the abutment 19 against the rim around the aperture.

The bar or shaft 16 has a diameter that is somewhat smaller than the aperture of the socket. A slack fit ensures easier sliding and rotating movements.

It may be desirable to make provision to hold the locking means in the inoperative position to facilitate assembling of the scaffold. One such method mayemploytheslidable mounting of the balance weight on the bar of the locking means. The balance weight would have a rectangular aperture for engaging the corresponding rectangular cross section formed at the end of the cylindrical bar. The balance weight would not be set apart from the brace in the inoperative position and it would prevent the sliding movement of the bar along the axis of the spigot as the rectangular hole on the balance weight would not be in register with the rectangular portion of the bar.

There may be several other designs embodying the principles of the invention that may be apparent to those skilled in the art.

Claims (12)

1. A scaffolding strut adapted, in use, to form a diagonal brace, the strut being of elongate construction and having adjacent at least one end thereof an elongate mounting formation extending transversely with respect to the longitudinal axis of the strut, said mounting formation including a central bore parallel to its longitudinal axis within which bore being housed a rotatable locking member adapted for setting in either operative or inoperative positions and having provision for chosen positions to be maintained by gravity.

2. A strut as claimed in Claim 1 wherein the mounting formation includes a cylindrical spigot member adapted to be received within matching socket formations on the horizontal and vertical components of the scaffold structure.

3. A strut as claimed in Claim 1 wherein the mounting formation includes a conical spigot member.

4. A strut according to any of the preceding claims wherein the mounting formation includes a rotatable head portion being also part of the locking means.

5. A strut according to Claim 4 wherein the head portion has the shape of a truncated cone with largest diameter being equal to that of the spigot.

6. A strut according to Claims 4 and 5 wherein the head portion includes a transversely projecting retaining formation having an abutment surface engagable with the rim of the receiving formation.

7. A strut according to Claim 6 adapted for mounting within receiving formations consisting of a circular bore and a groove extending the length of the socket providing a recess allowing the passage of the retaining formation on the head portion of the spigot.

8. A strut according to any preceding claims wherein the locking means include a circular shaft located in the bore of the spigot said shaft having length exceeding that of the spigot thus allowing sliding movement parallel with the axis of the spigot for effecting operative and inoperative attitudes of the locking means.

9. A strut according to any preceding claims being an elongate member of tabular construction.

10. A strut according to any preceding claims having mounting means produced of malleable cast iron.

11. A scaffolding strut substantially as hereinbefore described with reference to Figures 1 to 4 of the accompanying drawings.

12. A scaffolding structure incorporating at least one scaffolding strut as defined in any preceding claim.