GB2298469A

GB2298469A - A spigot for a spigot-and-socket joint

Info

Publication number: GB2298469A
Application number: GB9504226A
Authority: GB
Inventors: Demetrios Georgio Papadopoulos
Original assignee: SGB Services PLC
Current assignee: SGB Services PLC
Priority date: 1995-03-02
Filing date: 1995-03-02
Publication date: 1996-09-04
Also published as: GB9504226D0

Abstract

A spigot (1), for connecting a pair of scaffolding poles (2, 3), comprises a spherically shaped head (7) for locating the spigot (1) in the hollow end (8) of a scaffolding pole (3) and a conical tapered portion (5) for guiding the spigot (1) into the hollow end (8) of the scaffolding pole (3). The cylindrical base (4) of the spigot (1) is attached to or integral with the end of another scaffolding pole (2). A pair of spigots (figure 5) are also used to connect a pair of scaffolding poles (2) of a scaffolding frame (10) to a second pair of poles (3) of a second scaffolding frame (11).

Description

A SPIGOT FOR A SPIGOT-AND-SOCKET JOINT The present invention relates to a spigot for a spigot-and-socket joint and, more particularly, to a spigot for joining scaffolding components such as frames, tubular poles and the like.

Scaffolding is a temporary framework often used in the construction industry to support or to allow the hoisting, lowering or standing of workmen or materials when, for example, carrying out construction, alteration or demolition of buildings. A scaffolding framework consists of a number of "step frames" or "span frames" each comprising a pair of vertical tubular side poles connected to each other by appropriate cross-pieces and/or braces.

The tubular scaffolding poles are often connected to each other within the step or span frames by means of spigotand-socket joints, the plain or spigot end of one pole fitting into the enlarged or socket end of another pole.

One type of spigot which has been commercially used for connecting scaffolding poles in this way can be enlarged by placing additional sleeves over the spigot or can be expanded by means of outer screws, bolts or the like. This ensures a tighter fit and, thus, a more secure connection, whilst also enabling the two scaffolding poles to be readily disconnected upon dismantling the scaffolding frame.

Another type of spigot for connecting scaffolding poles is described in GB-A-2239505 (Grayston Central Services Limited). This prior specification discloses a pre-formed plastic spigot member having a lower portion frictionally or adhesively retained in a lower scaffolding pole and an upper portion for releasably engaging in the lower part of an upper scaffolding pole. The upper portion of the spigot member is shown to comprise a tapered upper end part which serves to facilitate location of the spigot in the lower part of the upper scaffolding pole and an annular recess which allows for engagement of locking means which may be provided in the lower part of the upper scaffolding pole.A further annular recess between two cylindrical portions of the spigot is also'provided and helps to reduce the area of the upper portion of the spigot in contact with the upper scaffolding pole, thereby helping to reduce frictional resistance to insertion and removal of the spigot from the upper scaffolding pole.

The scaffolding poles of a scaffolding frame may, however, be long, bulky and a scaffolding frame can weigh up to 25kg. Thus, it is often difficult to line up the ends of a pair of scaffolding poles of a frame and fit the spigots on one frame into the sockets of another frame accurately so that the two frames can be connected together. Until now, erection of a scaffolding frame has been a laborious, time-consuming process and generally requires at least two persons to connect a pair of scaffolding frames.

It is already known to provide the hollow or socket end of a scaffolding pole with an external "guiding1 sleeve which helps to position the hollow or socket end of the scaffolding pole over the spigot end of another scaffolding pole. However, it has been found that such an arrangement does not entirely alleviate the problem of accurately positioning and fitting together the two ends of a pair of scaffolding poles and such an arrangement also has the disadvantage of high production costs. Thus, the problem still exists.

According to one aspect of the present invention, there is provided a spigot for a spigot-and-socket joint, which spigot comprises a substantially cylindrical base portion, a substantially conical tapered portion formed at one end of the base portion and sloping inwardly toward the first end of a shank, the shank being of reduced diameter relative to the base portion, and a shaped head formed at a second end of the shank, wherein the shaped head comprises a substantially spherical portion having a diameter substantially equal to the diameter of the base portion. The substantially spherical portion of the spigot head enables the spigot head to be quickly and easily located in the socket of the spigot-and-socket and enables the spigot head to be offered to the spigot-and-socket joint from any direction.The spherical portion of the spigot head also enables the spigot to be rotated in the spigot-and-socket joint, as in a ball-and-socket joint, such that the spigot may be quickly and easily positioned and fitted into the spigot-and-socket joint with minimum skill and effort. The substantially conical tapered portion acts as a cam which also helps to guide the spigot into the spigot-and-socket joint.

Preferably, the shaped head is partly cut away.

This reduces interference and allows relative contraction and expansion of the spigot head so that the spigot head may be inserted more easily into the socket of a spigotand-socket joint, even where the socket is slightly deformed.

More preferably, the spigot is formed from a onepiece member. This has the added advantage of ease of manufacture and reduced production costs.

According to another aspect of the present invention, there is provided a tubular element provided with a spigot for connecting the tubular element to a second substantially identical tubular element, which spigot comprises a substantially cylindrical base portion, a first end of which is retained in one end of the said tubular element, the diameter of the cylindrical base portion being substantially equal to the internal diameter of the tubular element, a substantially conical tapered portion formed at a second end of the base portion and sloping inwardly towards a first end of a shank, the shank being of reduced diameter relative to the base portion, and a shaped head formed at a second end of the shank, the shaped head comprising a substantially spherical portion having a diameter substantially equal to the diameter of the base portion, wherein the base portion and shaped head are adapted to be dimensionally received, in use, by one end of the said second substantially identical tubular element.

Preferably, the spigot is dimensioned to releasably engage, in use the second substantially identical tubular element by means of a friction fit between the base portion and shaped head and an inner surface of one end of the second substantially identical tubular element. Such an arrangement provides a connection which is both temporary and secure.

Preferably, the spigot is formed from the same material as the tubular element. Again, this can lead to reduced production costs.

Conveniently, the first end of the base portion is adhesively retained within one end of the tubular element.

Alternatively, the first end of the base portion is integrally formed with one end of the tubular element.

According to a further aspect of the present invention, there is provided a spigot-and-socket joint, which joint comprises a first tubular element, a second tubular element substantially identical to the first tubular element and a spigot, the spigot comprising a substantially cylindrical base portion, a first end of which is retained in one end of the first tubular element, the diameter of the cylindrical base portion being substantially equal to the internal diameter of the first tubular element, a substantially conical tapered portion formed at a second end of the base portion and sloping inwardly towards a first end of a shank, the shank being of reduced diameter relative to the base portion, and a shaped head formed at a second end of the shank, the shaped head comprising a substantially spherical portion having a diameter substantially equal to the diameter of the base portion, wherein the base portion and shaped head are adapted to be dimensionally received, in use, by one end of the second tubular element to releasably engage the second tubular element.

Preferably, the second tubular element comprises a wall which is dimensioned and adapted to act, in use, as a pivot point for the shank and/or tapered portion of the spigot. This not only helps to position and fit the first and second tubular elements with respect to each other, particularly where the tubular elements are long, bulky, elements such as scaffolding poles, but also enables one tubular element to be supported on the other tubular element whilst positioning and'fitting the first and second tubular elements together.

According to yet another aspect of the present invention, there is provided a scaffolding frame which comprises a pair of scaffolding poles and a pair of spigots, a respective spigot being retained at one end of each of the two scaffolding poles, each spigot comprising a substantially cylindrical base portion, a first end of which is retained in one end of one of the two scaffolding poles, the diameter of the cylindrical base portion being substantially equal to the internal diameter of the respective scaffolding poles, a substantially conical tapered portion formed at a second end of the base portion and sloping inwardly towards a first end of a shank, the shank being of reduced diameter relative to the base portion and a shaped head formed at a second end of the shank, the shaped head comprising a substantially spherical portion having a diameter substantially equal to the diameter of the base portion, wherein each spigot is adapted to be dimensionally received, in use, in one end of each of a pair of respective second scaffolding poles of a second scaffolding frame. This enables the two scaffolding frames to be quickly and easily connected, even by a single person, with minimum skill and effort, despite the bulkiness and heavy weight of the scaffolding frames.

According to yet a further aspect of the present invention, there is provided a method of positioning a first tubular element with respect to a second substantially identical tubular element, which method comprises providing the first tubular element with a spigot having a substantially cylindrical base portion, a first end of which is retained in one end of the first tubular element, the diameter of the cylindrical base portion being substantially equal to the internal diameter of the first tubular element, a substantially conical tapered portion formed at a second end of the base portion and sloping inwardly towards a first end of a shank, the shank being of reduced diameter relative to the base portion and a shaped head formed at a second end of the shank, the shaped head comprising a substantially spherical portion having a diameter substantially equal to the diameter of the base portion, locating the shaped head in a receiving end of the second substantially identical tubular element and rotating the shaped head in, and guiding the spigot into, the receiving end of the second substantially identical tubular element until the spigot releasably engages the receiving end of the second substantially identical tubular element.

Preferably, the method further comprises the step of pivoting one or other of the first or second tubular elements against the other of the first or second tubular elements by means of the shank and/or tapered portion.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example only, with reference to the accompanying drawings in which: FIGURE 1 is a longitudinal part-sectional view of a scaffolding pole provided with a spigot according to the present invention, with the spigot in a first position with respect to the socket or receiving end of a further scaffolding pole; FIGURE 2 is a longitudinal part-sectional view of the arrangement of Figure 1 in a subsequent position; FIGURE 3 is a longitudinal part-sectional view of the arrangement of Figure 1 in a further subsequent position; FIGURE 4 is a longitudinal part-sectional view of the arrangement of Figure 1, with the spigot in a fully engaged position; and FIGURE 5 is an elevational view from one side of part of a scaffolding frame incorporating spigots according to the present invention, and part of a co-operating frame.

Referring to the drawings, a spigot 1 is provided for connecting a pair of elongate, tubular scaffolding poles 2, 3.

The spigot 1 is divided into four main portions, namely, a cylindrical portion 4, a chamfered portion 5, an elongate shank 6 and a substantially spherical head 7.

The scaffolding poles 2, 3 shown in figures 1 to 5 of the drawings each have a hollow end 8 and one end of the cylindrical portion 4 of the spigot is retained in the hollow end 8 of the upper 2 of the two scaffolding poles 2, 3. The diameter of the cylindrical portion 4, is equivalent to the internal diameter of the scaffolding poles 2, 3.

The chamfered portion 5 of the spigot 1 slopes inwardly from the unattached end of the cylindrical portion 4 towards one end of the elongate shank 6. The elongate shank 6 extends along the central longitudinal axis of the scaffolding pole 2 and separates the substantially spherical head 7 from the chamfered portion 5. The shank 6 is of reduced diameter relative to the cylindrical portion 4 and the substantially spherical head 7 has a diameter equivalent to the internal diameter of the scaffolding poles 2, 3.

The spigot 1 shown in FIGURE 4 is releasably received within the hollow or receiving end 8 of the lower 3 of the two scaffolding poles 2, 3. The diameter of the cylindrical portion 4 and the size of the substantially spherical head 7 of the spigot 1 is such that the cylindrical portion 4 and the substantially spherical head 7 fit tightly within the hollow end 8 of the lower scaffolding pole 3 to form a friction fit over two contact zones. This provides a connection which is both temporary and secure.

Each part of the spigot 1 plays an important role in the positioning and fitting together of the two scaffolding poles 2, 3.

Referring to Figures 1 to 4 of the drawings, an upper scaffolding pole 2 is connected to an already fixed, generally vertical, lower scaffolding pole 3 by initially positioning the spigot head 7 at the open mouth of the hollow end 8 of the lower scaffolding pole 3 with the shank 6 resting on or adjacent to the wall 9 of the hollow end 8 of the lower scaffolding pole 3. In this position, the upper scaffolding pole 2 and elongate shank 6 are at an angle to the lower scaffolding pole 3.

The substantially spherical shape of the spigot head 7 enables the spigot head 7 to be positioned quickly and easily at the open mouth of the hollow end 8 of the lower scaffolding pole 3 and enables the spigot head 7 to be offered to the open mouth of the hollow end 8 of the lower scaffolding pole 3 from any direction. By resting the elongate shank 6 on the wall 9 of the hollow end 8 of the lower scaffolding pole 3, the lower scaffolding pole 3 is able to provide support for the upper scaffolding pole 2 such that a substantial amount of weight acting on a person (not shown) holding the upper scaffolding pole 2 is transferred to the already fixed, generally vertical, lower scaffolding pole 3.A person holding the upper scaffolding pole 2 is, therefore, able to retain the upper scaffolding pole 2 with a proportion of its weight being supported by the wall 9 of the hollow end 8 of the lower scaffolding pole 3 and is, thus, more easily able to guide the spigot 1 into the hollow end 8 of the lower scaffolding pole 3.

The upper scaffolding pole 2 is pivoted or rotated into an upright position, with the spherical head 7 rotating within the socket defined by the mouth of the hollow end 8 of the lower scaffolding pole 3. The spherical head 7 and the mouth form a ball and socket joint permitting smooth rotation of the upper pole 2 relative to the lower pole 3 and preventing the spigot 1 on the upper pole 2 from slipping or falling out of the hollow end 8 of the lower pole 3. The upper pole 2 is rotated until the elongate shank 6 no longer rests on the wall 9 of the hollow end 8 of the lower scaffolding pole 3 and the central longitudinal axis of the elongate shank 6 is brought into substantial parallel alignment with the central longitudinal axis of the lower scaffolding pole 3.

Pivoting or rotation of the upper scaffolding pole 2 into the upright position is aided by the substantially spherical shape 7 of the spigot head 1. The chamfered portion 5 then acts as a cam to guide the upper part of the spigot 1 into the hollow end 8 of the lower scaffolding pole 3. The upper scaffolding pole 2 is then pushed further downwards (in the direction of the arrows shown in Figure 3) such that the cylindrical upper portion 4 of the spigot 1 is pushed further into the hollow end 8 of the lower scaffolding pole 3 until the edges of the two scaffolding poles 2, 3 meet to complete the connection.

The inner diameters of the hollow ends 8 of the scaffolding poles 2, 3 shown in the drawings are equal and the spigot 1 may just as conveniently be retained in the already fixed, generally vertical, lower scaffolding pole 3. In this arrangement, the open mouth of the hollow end 8 of the upper scaffolding pole 2 is simply placed over the spigot head 7 with the wall 9 of the hollow end 8 of the upper scaffolding pole 2 resting against the upright, vertical elongate spigot shank 6. In this position, the upper scaffolding pole 2 is supported by the lower scaffolding pole 3.The upper scaffolding pole 2 may then be pivoted or rotated into an upright position such that the wall 9 of the hollow end 8 of the upper scaffolding pole 2 is brought away from the elongate shank 6 and the central longitudinal axis of the upper scaffolding pole 2 is brought into substantial alignment with the central longitudinal axis of the elongate shank 6. The upper scaffolding pole 2 can then be pushed downwards such that the hollow end 8 of the upper scaffolding pole 2 is pushed further over the cylindrical portion 4 of the spigot 1 until the two ends of the scaffolding poles 2, 3 meet, to complete the connection.In the same way as described above, the substantially spherical shape of the spigot head 7 enables the hollow end 8 of the upper scaffolding pole 2 to be quickly and easily positioned over the spigot head 1 from any direction and enables the upper scaffolding pole 2 to be pivoted or rotated into an upright position. The chamfered portion 5, then acts as a cam to guide the hollow end 8 of the upper scaffolding pole 2 over the spigot 1.

The embodiment of the spigot shown in the drawings is a one-piece spigot with no moving parts and this has the added advantage of ease of manufacture and reduced production costs.

The embodiment of the spigot shown in the drawings is formed of a plastic material. The spigot 1 may, however, be made from the same material as the scaffolding poles 2, 3 (generally aluminium or steel) and may be formed as a casting or a moulding. Furthermore, instead of being retained in the hollow end 8 of one of the scaffolding poles 2, 3, the spigot 1 may be integrally formed with or otherwise connected to the end of one of the scaffolding poles 2, 3, as long as the spigot 1 remains attached when the scaffolding poles 2, 3 are disconnected during dismantling of a scaffolding frame 10, 11.

In the case where the hollow end 8 of a scaffolding pole 2, 3 is slightly deformed, as sometimes occurs, it is difficult to fit a substantially spherical spigot head 7 into the slightly deformed hollow end 8.

Thus, it is envisaged that the spigot head 7 could also be partially cut away in order to reduce interference and to allow relative contraction and expansion of the spigot head 7, so that the spigot head 7 may be inserted into the deformed hollow end 8 of a scaffolding pole 2, 3 more easily. In fact, in the case of a partially cut away spigot head 7, only three or four contact points between the inner surface of the wall 9 of the hollow end 8 of the scaffolding pole 2, 3 and the spigot head 7 would be necessary for a secure, but temporary, connection.

The shank 6 of the spigot 1 shown in the drawings is long enough to separate the head and chamfered portions 5. 7 such that one scaffolding pole 2, 3 can be pivoted or rotated about the other 2, 3 into a position in which connection may take place. Other embodiments are envisaged in which the shank 6 may, for example, be in the form of a web.

Although the embodiment of the invention has so far been described for use in connecting two scaffolding poles 2, 3 in a substantially vertical position, there is no reason why a spigot 1 according to the present invention cannot also be used to connect scaffolding poles 2, 3 in a substantially horizontal or diagonal position.

Furthermore, the spigot 1 according to the present invention will be useful for connecting many other types of different components, typically large, elongate components, rather than just scaffolding poles 2, 3.

The spigot 1 shown in the drawings, may be used with existing components or frame scaffolds and with existing cuplock components (not shown). No substantial modification of existing scaffolding components, is, therefore, required.

Figure 5 shows part of a pair of scaffolding frames 10, 11 each of which comprises a pair of scaffolding poles 2, 3 connected by cross-pieces 12. The lower ends of the scaffolding poles 2 in the upper scaffolding frame 10 are each provided with a spigot 1 according to the present invention. Although positioning and fitting together a pair of scaffolding poles 2, 3 is relatively difficult the situation is further complicated where a pair of scaffolding poles 2, 2 are connected by cross-pieces 12 in one scaffolding frame 10 and must be connected to another pair of scaffolding poles 3, 3 connected by cross-pieces 12 in another scaffolding frame 11, as shown in Figure 5. The spigots 1 provided at the end of the scaffolding poles 2, 2 of the upper scaffolding frame 10 in Figure 5, however, enable the two scaffolding frames 10, 11 to be quickly and easily positioned and fitted together in order to connect the two frames 10, 11. In fact, very little skill and effort are required to position and fit the scaffolding frames 10, 11 together using the spigots 1 of the present invention, and a pair of scaffolding frames 10, 11 can even be connected by a single person.

Claims

1. A spigot for a spigot-and-socket joint, which spigot comprises a substantially cylindrical base portion, a substantially conical tapered portion formed at one end of the base portion and sloping inwardly towards a first end of a shank, the shank being of reduced diameter relative to the base portion, and a shaped head formed at a second end of the shank wherein the shaped head comprises a substantially spherical portion having a diameter substantially equal to the diameter of the base portion.

2. A spigot according to claim 1, wherein the shaped head is partly cut away.

3. A spigot according to claim 1 or 2, wherein the spigot is formed from a one-piece member.

4. A spigot according to any one of claims 1 to 3, wherein the shank comprises a web.

5. A tubular element provided with a spigot for connecting the tubular element to a second substantially identical tubular element, which spigot comprises a substantially cylindrical base portion, a first end of which is retained in one end of the said tubular element, the diameter of the cylindrical base portion being substantially equal to the internal diameter of the tubular element, a substantially conical tapered portion formed at a second end of the base portion and sloping inwardly towards a first end of a shank, the shank being of reduced diameter relative to the base portion, and a shaped head formed at a second end of the shank, the shaped head comprising a substantially spherical portion having a diameter substantially equal to the diameter of the base portion, wherein the base portion and shaped head are adapted to be dimensionally received, in use, by one end of the said second substantially identical tubular element

6. A tubular element according to claim 5, wherein the shaped head is partly cut away.

7. A tubular element according to claim 5 or 6, wherein the spigot is dimensioned to releasably engage, in use, the second substantially identical tubular element by means of a friction fit between the base portion and shaped head and an inner surface of one end of the second substantially tubular element.

8. A tubular element according to any one of claims 5 to 7, wherein the spigot is formed form a one-piece member.

9. A tubular element according to any one of claims 5 to 8, wherein the shank comprises a web.

10. A tubular element according to any one of claims 1 to 9, wherein the tubular element comprises a scaffolding pole.

11. A tubular element according to any one of claims 5 to 10, wherein the spigot is formed from the same material as the tubular element.

12. A tubular element according to any one of claims 5 to 11, wherein the first end of the base portion is adhesively retained within one end of the tubular element.

13. A tubular element according to any one of claims 5 to 11, wherein the first end of the base portion is integrally formed with one end of the tubular element.

14. A spigot-and-socket joint, which joint comprises a first tubular element, a second tubular element substantially identical to the first tubular element and a spigot, the spigot comprising a substantially cylindrical base portion, a first end of which is retained in one end of the first tubular element, the diameter of the cylindrical base portion being substantially equal to the internal diameter of the first tubular element, a substantially conical tapered portion formed at a second end of the base portion and sloping inwardly towards a first end of a shank, the shank being of reduced diameter relative to the base portion and a shaped head formed at a second end of the shank, the shaped head comprising a substantially spherical portion having a diameter substantially equal to the diameter of the base portion, wherein the base portion and shaped head are adapted to be dimensionally received, in use, by one end of the second tubular element to releasably engage the second tubular element.

15. A spigot-and-socket joint according to claim 14 wherein the first and second tubular elements comprise a pair of scaffolding poles.

16. A spigot-and-socket joint according to claim 14 or 15 wherein the second tubular element comprises a wall which is dimensioned and adapted to act, in use, as a pivot point for the shank and/or tapered portion of the spigot.

17. A scaffolding frame comprising a spigot according to any one of claims 1 to 4, or a tubular element according to any one of claims 5 to 13.

18. A scaffolding frame which comprises a pair of scaffolding poles and a pair of spigots, a respective spigot being retained at one end of each of the two scaffolding poles, each spigot comprising a substantially cylindrical base portion, a first end of which is retained in one end of one of the two scaffolding poles, the diameter of the cylindrical base portion being substantially equal to the internal diameter of the respective scaffolding poles a substantially conical tapered portion formed at a second end of the base portion and sloping inwardly towards a first end of a shank, the shank being of reduced diameter relative to the base portion and a shaped head formed at a second end of the shank, the shaped head comprising a substantially spherical portion having a diameter substantially equal to the diameter of the base portion, wherein each spigot is adapted to be dimensionally received, in use, in one end of each of a pair of respective second scaffolding poles of a second scaffolding frame.

19. A method of positioning a first tubular element with respect to a second substantially identical tubular element, which method comprises providing the first tubular element with a spigot having a substantially cylindrical base portion, a first end of which is retained in one end of the first tubular element, the diameter of the cylindrical base portion being substantially equal to the internal diameter of the first tubular element, a substantially conical tapered portion formed at a second end of the base portion and sloping inwardly towards a first end of a shank, the shank being of reduced diameter relative to the base portion, and a shaped head formed at a second end of the shank, the shaped head comprising a substantially spherical portion having a diameter substantially equal to the diameter of the base portion, locating the shaped head in a receiving end of the second substantially identical tubular element and rotating the shaped head in and guiding the spigot into, the receiving end of the second substantially identical tubular element until the spigot releasably engages the receiving end of the second substantially identical tubular element.

20. A method according to claim 19, further comprising the step of pivoting one or other of the first or second tubular elements against the other of the first or second tubular elements by means of the shank and/or tapered portion.

21. A spigot substantially as hereinbefore described, with reference to, and as shown in, Figures 1 to 5 of the accompanying drawings.

22. A tubular element, substantially as hereinbefore described, with reference to, and as shown in, Figures 1 to 5 of the accompanying drawings.

23. A spigot-and-socket joint, substantially as hereinbefore described, with reference to, and as shown in, Figure 4 of the accompanying drawings.

24. A scaffolding frame, substantially as hereinbefore described, with reference to, and as shown in, Figure 5 of the accompanying drawings.

25. A method substantially as hereinbefore described, with reference to the accompanying drawings.

26. Any novel feature or combination of features described herein.