GB2433302A

GB2433302A - Connector

Info

Publication number: GB2433302A
Application number: GB0525522A
Authority: GB
Inventors: David Legg
Original assignee: Redman Fisher Engineering Ltd
Current assignee: Redman Fisher Engineering Ltd
Priority date: 2005-12-15
Filing date: 2005-12-15
Publication date: 2007-06-20
Anticipated expiration: 2025-12-15
Also published as: GB0525522D0; GB2433302B

Abstract

A connector (10) comprises a socket (12c) comprising a socket wall (14c) which encloses a generally cylindrical space. An interior surface of the socket (12c) includes two support projections (16c, 16c') which extend inwardly into the generally cylindrical space.

Description

I 2433302 Title: Connector Descriition of Invention The present

invention relates to a connector for joining generally cylindrical structural elements.

It is known to use metallic tubes for creating structures such as safety barriers and handrails, market stalls and exhibition stands, and childrens' play equipment and the like. In order to create such structures, a plurality of different configuration tube connectors are provided to join tubes in a variety of different relative orientations. Such tube connectors typically comprise, for each tube to be joined, a generally cylindrical socket, and a grub screw which extends through a threaded aperture into the socket generally normal to a longitudinal axis of the socket.

Tubes are joined using such a connector by inserting into each socket of the connector a generally cylindrical tube with an outer diameter which is marginally less than the inner diameter of the socket so that a longitudinal axis of the tube generally coincides with the longitudinal axis of the socket. The grub screw is then screwed into the socket, typically using an Allen key, so that an end of the grub screw bears upon an end of the tube located in the socket, and pushes the tube against the interior surface of the socket, thus S. locking the tube in the socket.

It will be appreciated that exact shape and dimensions of the tubes and * connector sockets will vary slightly according to the tolerance to which the *. : 25 parts are manufactured, and thus the tubes will never fit perfectly inside the connector sockets, and there will be some lateral movement of a tube inside a * connector socket as the grub screw is tightened. Moreover, as neither the tube or connector socket are likely to be perfectly cylindrical, only a relatively small portion of the outer surface of the tube end is likely to be engaged with the interior surface of the socket. Thus, the location and magnitude of the loads to which the tube and connector are subjected will be highly variable, and therefore in order to ensure that the likelihood of failure of the connector is acceptably low, it is necessary to limit the maximum applied loading, thus resulting in the likelihood of over engineered structural designs. In particular, maximum structural efficiency through optimisation of material and fabrication is not achieved in all applications.

According to a first aspect of the invention we provide a connector for joining structural elements, the connector comprising a socket, the socket comprising a socket wall which encloses a generally cylindrical space with a longitudinal axis, an interior surface of the socket being provided with two support projections which extend inwardly into the generally cylindrical space.

By virtue of the provision of such support projections, the points at which a tube, when inserted into the socket, contacts the interior surface of the socket is more predictable, and thus the loads to which the connector is subjected during use may be more readily controllable. In particular, the maximum structural efficiency may be achieved through optimisation of material and fabrication in all fabrications.

Preferably the connector further comprises a securing device comprising a threaded fastener which extends through a correspondingly threaded aperture *. in the socket wall. In this case, preferably the threaded aperture extends into * :. the socket generally normal to the longitudinal axis of the socket.

* By virtue of the provision of the support projections, when a structural element such as a generally cylindrical tube is inserted into the socket and the threaded fastener tightened, the tube is pushed against the support projections rather than the generally cylindrical portion of the interior surface of the socket.

In this case, a centre point of each support projection and a centre point of the threaded aperture are preferably aligned so that they lie in a plane which extends generally perpendicular to the longitudinal axis of the generally cylindrical space.

Preferably the threaded aperture is located approximately diametrically opposite to the mid-point between the two support projections.

By virtue of this arrangement, when a structural element such as a generally cylindrical tube is inserted into the socket and the threaded fastener screwed into the socket, the threaded fastener may push the tube onto each of the support projections with an approximately equal force.

The threaded aperture and support projections may be spaced approximately equidistant from one another around the interior surface of the socket.

The support projections may have a generally circular uppermost surface.

According to a second aspect of the invention we provide a method of assembling a structure comprising the steps of inserting an end portion of a structural element into socket in a connector, the socket comprising a socket wall which encloses a generally cylindrical space, the end portion of the structural element having an outer surface which is generally circular in transverse cross-section, screwing a threaded fastener into a correspondingly threaded aperture in the socket wall so that the fastener engages with the end portion of the structural element and pushes the end portion of the structural element against two support projections which extend inwardly from an interior surface of the socket wall.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings of which, Figure 1 is an illustration of a perspective view of a connector in accordance with the first aspect of the invention, Figure 2 is an illustration of a front elevation of the connector shown in Figure 1 with a structural element shown in place in a socket of the connector, Figure 3 is an illustration of a perspective view of a second embodiment of connector according to the invention, Figure 4 is an illustration of a perspective view of a third embodiment of connector according to the invention, Figure 5 is an illustration of a perspective view of a fourth embodiment of connector according to the invention.

Referring now to the figures there is shown various configurations of connector for connector structural elements which have an end portion with an outer surface having a generally circular transverse cross-section. In this example, the connectors are adapted to connect generally cylindrical tubes.

Considering first the embodiment of connector shown in Figure 1, the connector 10 is generally T-shaped, and is adapted to connect three generally cylindrical tubes. The connector 10 comprises three sockets 12a, 12b, 12c each of which has a socket wall 14a, 14b, 14c which encloses a generally cylindrical space with a longitudinal axis A, B and C. The longitudinal axes A, B of two of the sockets 12a, 12b generally coincide, whereas the longitudinal axis C of the third socket 12c extends at right angles to the other axes A, B. a...

An interior surface of each socket 12a, 12b, 12c is provided with two support projections 16c, 16c' which extend inwardly of the socket wall 14a, 14b, 14c into the generally cylindrical space. Each support pad is a protuberance . : which, in these examples has a generally circular, flat top surface of around * 13mm in diameter, and a height of around 1.5mm, 50 that the protuberance *e*aSS * 25 extends into the generally cylindrical space by around 1.5mm. Whilst the protuberances may have the form of a truncated cone, in this embodiment of the invention, the inclined sides of the protuberances are generally convex.

Each socket 12a, 12b, 12c of the connector 10 is provided with a threaded fastener 18a, 18b, 18c, in this example a grub screw, which is located in a correspondingly threaded aperture in the socket wall 14a, 14b, 14c. The threaded aperture is provided in a thickened portion 20a, 20b, 20c of the socket wall 14a, 14b, 14c, and extends into the generally cylindrical space provided by the socket 1 2a, 1 2b, 1 2c generally normal to the longitudinal axis A, B, C of the socket 12a, 12b, 12c in question.

The centre point of the circular top surface of each protuberance, and the centre of the threaded aperture are all aligned in a place which extends generally normal to the longitudinal axis A, B, C of the generally cylindrical space in question. This location of the support projections 1 6c, 1 6c' moves the stress exerted on the socket 12a, 12b, 12c inwardly from the edge of the socket 12a, 12b, 12c. The Applicant has found that in prior art arrangements, the load exerted by a tube on the socket 12a,12b, 12c tends to be concentrated at the edge of the socket 12a, 12b, 12c, which will yield if excessive loading is applied to the tube, resulting in failure of the connector at intersection between sockets 12a, 12b, 12c. By moving the loading inwardly of the socket edge, the Applicant has found that the tendency to fail at the intersection is reduced, and thus the permitted loading of the connector may be maximised, within all practical tolerance variations.

The threaded aperture in each socket is diametrically opposite the mid-point between the two support projections 16c, 16c', and in this example, the support projections 16c, 16c' and threaded aperture are spaced approximately equidistant around the socket wall 14a, 14b, 14c. This arrangement of the support projections 16c,16c' has an advantage that the force exerted by the grub screw 18a, 18b, 18c on the tube is distributed generally evenly between the support projections 16c, 16c'.

The connector 10 is used as follows.

An end portion of a structural element 22a, 22b, 22c, in this example a tube with a generally circular transverse cross-section, is inserted into each socket 12a, 12b, 12c, and the grub screw 18a, 18b, 18c screwed into the correspondingly threaded aperture in the socket wall 14a, 14b, 14c so that the grub screw 18a, 18b, 18c engages with the end portion of the structural element 22a, 22b, 22c and pushes the end portion of the structural element 22a, 22b, 22c against the support projections 16c, 16c', and the grub screw 18a, 18b, 18c tightened until the structural element 22a, 22b, 22c is locked in the socket 12a, 12b, 12c. The structural elements 22a, 22b, 22c are thus each supported in the socket 12a, 12b, 12c through three discrete contact areas, namely the grub screw 18a, 18b, 18c and the two support projections 16c, 16c'.

As the aperture in which each grub screw 1 8a, 1 8b, 1 8c is located is generally diametrically opposite to the mid-point between the two support projections 16c, 16c', the force exerted by the grub screw 18a, 18b, 18c on the structural element 22a, 22b, 22c is distributed generally evenly between the two support projections 16c, 16c'. Moreover, the height of the support projections 16c, 16c', and the relative dimensions of the socket wall 14a, 14b, 14c and the structural element 22a, 22b, 22c are selected such that when the structural element 22a, 22b, 22c is pushed against the support projections 1 6c, 1 6c', the structural element 22a, 22b, 22c is located generally centrally in the socket 12a, 12b, 12c. This improves the visual appearance of the assembly.

* :. It will be appreciated that the invention is not restricted to use with a T-shaped * . connector. A wide variety of configurations of connector are currently in use to * 25 join structural elements such as cylindrical tubes, and the invention may be applied to any such configuration of connector. Further examples of connectors are illustrated in Figures 3, 4 and 5.

Figure 3 shows a connector 10' for joining two structural elements generally in line with one another (known as a sleeve connector). Figure 4 shows a connector 100 for joining three structural elements together to form a right-angled corner. Figure 5 shows a connector 100' for joining four structural elements to a fifth structural element. Each socket of these connectors 10', 100, 100' also include two support projections, and the connectors 10', 100, 100' operate in exactly the same way as the connector 10 illustrated in Figures 1 and 2.

It should be appreciated that in certain arrangements of connector, it may not be possible for the top surface of every support projection to be circular, because of limited space within the socket in question. In this case, the top surface of each support projection may be semi-circular.

Connectors 10, 10', 100, 100' according to the invention may, for example, be used to connect steel tubes conforming to EN 392001, BS EN 10210-1 or BS1387 (light, medium or heavy duty) standards, or BS1139-1.2 1990 aluminium scaffold tubes, and can be configured to be used in relation to tubes of a variety of outside diameters. When used in relation to a tube with an outer diameter of 26.9mm, the outer diameter of each socket is typically 39.6mm, and for tubes with outer diameters of 33.7mm, 42.4mm, 48.3mm and 60.3mm, the outer diameter of each socket is typically 48mm, 56.7mm, 62.6mm and 75.7mm respectively.

Typically the connectors 10, 10', 100, 100' are made from a metallic material, by casting. The connectors 10, 10', 100, 100' may, however, be made from a S...

plastic, or polymeric material.

When used in this specification and claims, the terms comprises1' and "comprising" and variations thereof mean that the specified features, steps or *:.: 25 integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for perlorming the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof. S.

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Claims

Claims 1. A connector for joining structural elements, the connector

comprising a socket, the socket comprising a socket wall which encloses a generally cylindrical space with a longitudinal axis, an interior surface of the socket being provided with two support projections which extend inwardly into the generally cylindrical space.
2. A connector according to claim 1 wherein the connector further comprises a securing device comprising a threaded fastener which extends through a correspondingly threaded aperture in the socket wall.
3. A connector according to claim 2 wherein the threaded aperture extends into the socket generally normal to the longitudinal axis of the socket.
4. A connector according to claim 3 wherein a centre point of each support projection and a centre point of the threaded aperture are aligned such that they lie in a plane which extends generally perpendicular to the longitudinal axis of the generally cylindrical space.
5. A connector according to claim 2 or 3 wherein the threaded aperture is located approximately diametrically opposite to the mid-point between the two support projections.

*
6. A connector according to claim 5 wherein the threaded aperture and support projections are spaced approximately equidistant from one another around the interior surface of the socket.

*.
7. A connector according to any preceding claim wherein the support * projections has a generally circular upper surface.

*.**** * *
8. A method of assembling a structure comprising the steps of inserting an end portion of a structural element into socket in a connector, the socket comprising a socket wall which encloses a generally cylindrical space, the end portion of the structural element having an outer surface which is generally circular in transverse cross-section, screwing a threaded fastener into a correspondingly threaded aperture in the socket wall so that the fastener engages with the end portion of the structural element and pushes the end portion of the structural element against two support projections which extend inwardly from an interior surface of the socket wall.

9. A connector substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

10. A method of assembling a structure substantially as hereinbefore described with reference to the accompanying drawings.

11. Any novel feature or novel combination of features described herein and/or in the accompanying drawings. S. * S * *5. *55 S * S S. I. **

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