GB2205379A - A joint - Google Patents

Abstract

A joint (14) between two elements (10, and 12) of a structure comprises e.g. a hollow upright (10) having an opening in a side wall to receive the end of the second element (12) and an opening (18) in an opposite side wall to receive a threaded member (22). The second element (12) has an internal thread formed from two or more lips (26) pressed from the wall of the second member (12). <IMAGE>

Description

A JOINT This invention relates to a joint to enable two elements of a structure to be secured together, and to a method of forming a thread in one of said elements.

It is known in a joint between two elements of a structure to secure the two elements together by a threaded member such as a bolt passing through one of the elements and engaging with a nut secured to the other one of said elements. The nut can be welded or otherwise secured in the other one of the elements.

The present invention seeks to provide a method of forming a thread or part of a thread in one of the elements both in order to avoid the necessity of providing a separate nut and of securing the nut within the element, but also to provide a relatively inexpensive, neat and strong joint between the two elements.

Accordingly the present invention provides a hollow structural element having a wall including thread means, the thread means comprising at least two lips formed from the wall of the structural element, the lips extending inwardly from the wall to form at least part of an internal thread engagable by a threaded member.

The lips can be staggered to more closely simulate an internal thread and two pairs of lips can be formed, the lips in each pair being staggered axially with respect to one another.

Each lip can be rectangular in form or the end of each lip engagable by the threaded member can have an arcuate surface.

The present invention further provides a joint for two elements of a structure, the joint comprising a first element in the form of a hollow structural element having a wall including thread means, the thread means comprising at least two lips formed from the wall of the first element, the lips extending inwardly from the wall to form an internal thread engagable by a threaded member, and a second element having an opening to receive a threaded member.

The second element can be a sheet or a further hollow structural section.

The first element can be hollow and rectangular in section and the second element can be hollow and tubular in section and also have a rectangular opening to receive the first element.

The thread means in the first element can be formed at a distance from one end of the first element at a distance less than the external diameter of the second element.

The present invention will now be more particularly described with reference to the accompanying drawings in which Fig. 1 shows part of a structure incorporating two joints according to the present invention, Fig. 2 shows one of the joints shown in Fig. 1 in greater detail, Fig. 3 shows in greater detail an end of one of the elements of the joint shown in Fig. 2 and Fig. 4 shows in greater detail the other part of the joint shown in Fig. 2.

Referring to the figures, in Fig. 1 there is shown part of a structure which includes an upright 10 and two cross pieces 12.

The structure for example can be a frame for an article of furniture, a display stand, an audio equipment rack or an audio visual equipment rack. The cross pieces 12 are secured to the upright 10 by a joint 14 which is shown in more detail in Fig. 2.

Referring to Figs. 2, 3 and 4, the upright 10 is hollow and tubular in cross-section and the cross piece 12 is rectangular in cross-section. The upright 10 has a first opening 16 which is rectangular in shape in order to receive the cross piece 12.

Opposite to the first opening 16 there is a second circular opening 18 in a part 20 of the upright 10 which has been dished.

The opening 18 is sized to receive a screw 22 having a countersunk head 24.

Adjacent to one or both ends of the cross piece 12, four lips 26 are formed from the walls of the cross piece 12 so as to form two pairs of opposed lips. The two pairs are staggered axially with respect to one another so as to simulate part of an internal thread with which the screw 22 can engage.

In order to assemble the upright 10 and cross pieces 12 to make the joints 14, each cross piece is inserted through the first opening 16 in the upright 10 and the screw is passed through the opening 18 so that the ethread engages with one or more of the lips 26. Rotation of the screw 22 draws the cross piece 12 into the upright 10 so that the cross piece 12 is held against axial movement by the tightening of the screw 22 in the lips 26 and is also supported by contact with the edges of the hole 16.

The lips 26 are formed at a distance from the nearest end of the cross piece 12, less than the external diameter of the upright 10 so that the openings formed by the creation of the lips are concealed from view when the upright of the cross pieces are assembled to make the joints 14.

The lips are rectangular in shape and are inclined at an angle greater than 90 degrees to the walls of the cross pieces 12.

The cross pieces 12, or similar elements need not always be attached to uprights, or other hollow sections, but can be attached to sheets or walls or articles of furniture. In such cases the sheet or wall need only have an opening for a screw or bolt to engage the thread means.

In order to simulate an internal thread it may not be necessary to provide four or more lips and two oppositely arranged tabs would normally be sufficient to simulate an internal thread for engagement with a screw of the type illustrated.

If necessary the ends of the lip which engage the screw can be radiused so that the surface of the lips contacted by the screw are continuous as opposed to a point contact in the case of a purely rectangular lip.

It is not essential that the upright is circular in section and the cross piece rectangular, though it is preferred that the cross piece is polygonal so that rotation of the cross piece with respect to the upright can be prevented.

For example, both the upright and the cross piece can be circular, rectangular or polygonal and other means if necessary may be provided to prevent relative rotation.

It will be appreciated that the present invention avoids the need for providing and securing a separate nut within the cross piece 12 by the relatively simple means of ereating an internal thread by pressing out the lips from the walls of the cross piece 12.

Claims (12)

1. A hollow structural element having a wall including thread means, the thread means comprising at least two lips formed from the wall of the structural element, the lips extending inwardly from the wall to form an internal thread engagable by a threaded member.

2. An element as claimed in claim 1 in which the lips are axially staggered with respect to one another.

3. An element as claimed in claim 1 in which the thread means includes four lips arranged in two pairs, the pairs of lips being staggered axially with respect to one another.

4. An element as claimed in any one of the preceding claims in which each lip is rectangular in form and is inclined at an angle greater than 90 degrees to the wall of the element.

5. An element as claimed in claims 1 to 3 in which the free end of each lip has an arcuate surface to engage the threaded member.

6. A joint for two elements of a structure, the joint comprising a first element as claimed in any one of the preceding claims and a second element having an opening to receive a threaded member.

7. A joint as claimed in claim 6 in which the second element is a sheet and the elements are secured together by a threaded member passing through an opening in the second element and engaging the thread means of the first element.

8. A joint as claimed in claim 6 in which the second element is hollow and tubular in section and the first element is hollow and rectangular in section, the second element having a rectangular opening to receive the first element.

9. A joint as claimed in claim 8 in which the thread means in the first element is formed at a distance from one end of the first element less than the external diameter of the second element.

10. A structural element constructed and arranged substantially as herein described and with reference to the accompanying drawings.

11. A joint constructed and arranged substantially as herein described and with reference to the accompanying drawings.

12. A structure including a joint as claimed in any one of the preceding claims.