GB2162920A - Joint assembly between tubular members - Google Patents

Abstract

A joint assembly between a pair of tubes (11, 12) includes a separate first member (18, 19) within each tube (11, 12) and movable transversely towards the wall of the tube (11, 12) by a fastener (14, 15) passing through the tube wall, and two (or one) second members (25) each extending within each tube, the second member(s) 25 and/or the first members (18, 19) being so wedge-shaped that actuation of the fasteners (14, 15) in a tightening mode causes mutual clamping of the parts to form a rigid joint assembly. An enlarged assembly can include three or more tubes joint in a comparable manner, and the arrangement can be such that before final tightening of the fasteners one or more of the tubes can be pivotable relative to others of the tubes. <IMAGE>

Description

SPECIF.ICATION Joint assembly between tubular members This invention relates to a joint assembly between two tubular members.

When tubular members have to be joined to form a framework or other structure, it is desirable that they can be united simply and easily and in desired dispositions. It is furthermore desirable the originally chosen dispositions are maintained in use, and that if such a joint does -loosen, it can be easily tightened and the original dispositions easily reattained.

The invention will be discussed first in relation to the-co-axial end-to-end joining of tubes.

Previously, such co-axial end-to-end joints have. been made by a variety of methods. The commonest of these is a mortise and tenon joint, wherein one tube has an insert fixed within it permanently or temporarily which provides an outwardly extending tenon intended to fit within the lumen of the other tube, a screw or the like passing through the wall of the other tube and engaging the tenon to complete the joint. Such a system has several disadvantages. In order to take account of manufacturing tolerances in the tenons and tubes, the tenons have to be made undersize, which can lead to 'sloppiness' in the eventual joint, pivoting taking place about the screw fastening. Use of two or more screws introduces more tolerance problem and increases cost and complexity.Further, tenons are usually installed during manufacture before the application of paint or plastics sheathing to metal tube members. Such coatings increase the size of the tenons making it difficult to introduce them into the tubes.

Maskings is timeconsuming and therefore expensive. All these disadvantages are magnified when the joints concerned are in frames for furniture, when for reason of space, frame parts will normally be transported to customers and the frames assembled in situ. In these conditions workshop facilities are not available and the assembly process needs to be simple and- trouble free, not least by reason of the impression given to the customer if the assembler has to struggle for some time to errect the- frameworks.

It is an object of the present invention, therefore, to provide an improved joint assembly between two tubes.

Accordingly, the invention provides a joint assembly between two tubes comprising a first member disposed within an end portion of each tube engaged with a fastener passing through the tube wall and capable of moving the first member transversely of the tube major axis, and at least one second member having a portion thereof disposed within each tube, the first and/or the second member providing a wedging surface engaging with the other member such that actuation of said fastener causes movement of the first member into engagement with the second member to urge it into engagement with the tube wall.

The fastener can be a screw threaded fastener and can draw the first member towards the tube wall by engagement within a threaded aperture in the first member.

The first member can be a block having on its lateral edges wedge surfaces for cooperation with a respective second member on each side thereof.

The or each second member can be a length of circular section bar or tube.

As an alternative one or both lateral edges of the first member can be rectangular and the or each second member can provide a wedge surface.

A further possibility resides in both the first and second members providing complementary wedging surfaces.

The first member in each tube can have, on its end remote from the other tube, a plate or the like for limiting entry of the second member(s) into the one tube.

The invention also provides a joint assembly between two tubes comprising a first member disposed within an end portion of each tube engaged with a fastener passing through the tube wall and capable of moving the first member transversely of the tube major axis, and at least one second member having a portion thereof disposed within each tube, the first and/or the second member providing a wedging surface engaging with the other member such that actuation of said fastener causes movement of the first member into engagement with the second member to urge it into engagement with the tube wall, wherein the said portions of the second member are disposed at an angle to each other.

The invention will be described further, by way of example, with reference to the accompanying drawings, wherein: Fig. 1 is a sketch illustrating a first preffered embodiment of joint assembly of the invention; Fig. 2 illustrates how a cross joint can be made using assemblies of the invention; Fig. 3 illustrates a second way in which a cross joint can be made; Fig. 4 is a cross-sectional view illustrating the application of the invention to circular tubes; Fig. 5 illustrates a variation; and Fig. 6 illustrates the application of the invention to square section tubing.

Fig. 7a is an exploded view of a further embodiment of assembly of the present invention; Fig. 7b shows this embodiment assembled; Fig. 7c shows this embodiment in a different configuration; Fig. 8a is an exploded view of a still further embodiment of assembly; Fig. 8b shows the embodiment of Fig. 8a assembled in a first configuration; Fig. 8c and 8d show the second embodiment assembled in second and third configurations; Fig 9a is an exploded view of a yet further embodiment of assembly of the invention; Fig. 9b to 9f are views of the further embodiment of Fig. 9a assembled in various configurations; Fig. 1 0a is an exploded view of another embodiment of assembly of the invention; Figs. 1 Ob to 1 0d are views of the embodiment of Fig. 1 Oa of assembly assembled in various configurations:: Fig. I la is an exploded view of a further embodiment of assembly of the invention; Fig. 11 b shows the assembly of Fig. 11 a in its completed form; Fig 1 2a is an exploded view of an additional embodiment of assembly of the invention; and Fig. 12b shows the assembly of Fig. 1 2a after completion.

A preferred joint assembly 10 of the invention (Fig.1) is made between two oblongsection steel tubes 11, 12, each of which has a square-cut free end surface 11 a, 1 2a. Tube 11 is shown secured, as by welding, to a further tube 13, but it could equally well simply be a straight length of tubing. Each tube 11, 1 2 has formed adjacent its end surface 11 a, 12a an aperture 14, 15 in a major-sidewall 16, 17. The end portion of each tube 11, 1 2 accommodates a first member in the form of a block 18, 19 of metal which is trapezium shaped having parallel front and rear walls and wedge surfaces 20 disposed at 45 to the front and rear walls.

Each surface 20 defines a generally triangular space with adjacent major and minor side wall portions. A fastener in the form of a hexagonal-socket-headed screw 21, 22 passes through each aperture 14, 15 and engages a complementarily threaded aperture 23, 24 in the blocks 18, 19.

A pair of second members are provided each in the form of a length of circular-section steel bar 25, half of which is accommodated in the aforementioned-triangular space in each tube 11, 12. Excessive penetration of bars 25, and possible loss within the tubes 11, 12 is prevented by a pair of respective end plates 26 secured to the blocks 18, 19.

When the screws 21, 22 are tightened with the end surfaces 11 a, 12a in abutting relationship, the blocks 18, 19 urge the bars 18, 19, into tight engagement with the adjacent side walls of the tubes 11. 12 and clamp them to form a secure and accurately aligned joint.

Fig. 2 shows a cross joint utilizing two joint assemblies comparable to that of Fig, 1, similar reference numerals having been used for similar parts.

Fig. 3 shows an alternative way of forming an "overlap" cross-joint. Here, a short length of tube 27 welded to an upright 28 has a single clamp block 29 which secures bars 30 which project on both sides and are engaged by clamp blocks 31, 32 in end portions of cross tubes 33, 34.

In Figs. 2 and 3 the operation of the parts is in all respects comparable to that of the joint assembly of Fig. 1.

Fig. 4 is a cross-sectional view through part of a joint assembly between two circular sectional tubes. Each tube 35 has a pair of apertures 36 adjacent its free edge and each accommodate a screw 37 which engages a clamp block 38 comparable with blocks 18, 19. Each block 38 engages and clamps a bar 40 against the tube sidewall.

A joint assembly using only one block 38 would be possible, but vr)ould be less secure than an assembly using two blocks 38.

Fig. 5 illustrates a variation wherein wedge surfaces are provided on second members which are in the form of generally triangular bars 42 a block 43 engaged by a fastener 44 being generally rectangular. If both the block 43 and the bars 42 are tapered, a particularly firm locking action can be generated, -suitable for high loadings, although manufacturing costs are increased.

Fig. 6 illustrates how the invention can be applied to joints in square section tubes, the principles involved being the same as those applicable to Fig. 4.

Figs. 7a to 7c show a further embodiment of assembly-of the invention wherein two oblong tubes 50, 51 having square cut ends 52, 53 are joined using first members 54 and bar-like second members 55, each having straight end portions disposed at 90, to each other. The operation of the assembly is comparable to the operation of the assemblies described in our above mentioned co-pending application. When the assembly is loosely connected, with members 55 free to pivot, the joint can be pivoted through 90 between the configurations illustrated in Figs. 7b and 7c.

Figs. 8a and 8d show a still further embodiment of assembly between three tubes 56, 57, 58. Each tube end has therein a first member 59 and three second members 60, 61 and 62 are provided. Member 60 is straight and members 61 and 62 have rightangle bends. The joint, when assembled can be a Tee-joint with the three tubes having their major planes in a common plane (as in Fig. 8a). Figs. 8b and 8c show a different type of Teejoint, and Fig. 8d shows how tube 58 can be pivoted relative to the other tube.

The fasteners can be tightened to secure the joint in any configuration.

Figs. 9a to 9f show a yet further embodiment of assembly wherein three tubes 63 are united using first members 64 and three rightangled second members 65. Figs. 9b to 9f show various possible configurations of the assembly.

Figs. 1 0a to 1 0d show another embodiment of joint assembly for four tubes 66 using four first members 67 and four rightangled second members 68. Figs. 1 Ob to 10d show three possible configurations for the completed assembly.

Figs. 11 a and 11 b show a still further embodiment of joint assembly between a pair of oblong section tubes 69, 70 with mitred ends. The tubes 69, 70 are united using two first members 71, and a 90 angled second member 72, one straight member 73 and a balancing rod 74. Fig. 11 b shows the assembly completed.

Figs. 1 2a and 12b show an additional embodiment of joint assembly of the invention. A pair of square-section tubes 75, 76 having mitred ends are-united using two first members 77 and two 90 angled second members 78.

The method of completing and constructing each of the above embodiments is comparable to the methods described in relation to the embodiments of Figs. 1 to 6.

The invention is not limited to the precise details of the foregoing and variations can be made thereto. For example, the joint assemblies of the invention can be applied to tubes of any practicable crosssection. In making an angled joint, eg a right angles mitred joint or a 145 angle joint, the tube ends would be cut accordingly, and the straight bars replaced by angled second members, the angles of the second members being arranged at the plane of contact of the two ends of the tubes. The shapes and angles of the wedge surfaces and the shape of the second members can be chosen at will to suit various circumstances.

Claims (18)

1. A joint assembly between two tubes comprising a first member disposed within an end portion of each tube engaged with a fastener passing through the tube wall and capable of moving the first member transversely of the tube major axis, and at least one second member having a portion thereof disposed within each tube, the first and/or the second member providing a wedging surface engaging with the other member such that actuation of said fastener causes movement of the first member into engagement with the second member to urge it into engagement with the tube wall.

2. An assembly as claimed in claim 1, wherein the fastener is a screw threaded fastener and is mounted to draw the first member twoards the tube wall by engagement within a threaded aperture in the first member.

3. An assembly as claimed in claim 1 or 2 wherein the first member is a block having on its lateral edges wedge surfaces for cooperation with a respective one of said second member on each side thereof.

4. An assembly as claimed in any preceding claim wherein the or each second member is a length of circularsection bar or tube.

5. An assembly as claimed in claim 1, 2 or 3, wherein one or both lateral edges of the first member is or are rectangular and the or each second member provides a wedge surface.

6. An assembly as claimed in claim 1, 2 or 3 wherein both the first and second members provide complementary wedging surfaces.

7. An assembly as claimed in any preceding claim wherein the first member in each tube has, on its end remote from the other tube, means for limiting entry of the second member(s) into the one tube.

8. An assembly as claimed in claim 7 wherein said means is a plate or block.

9. A joint assembly between two tubes comprising a first member disposed within an end portion of each tube engaged with a fastener passing through the tube wall and capable of moving the first member transversely of the tube major axis, and at least one second member having a portion thereof disposed within each tube, the first and/or the second member providing a wedging surface engaging with the other member such that actuation of said fastener causes movement of the first member into engagement with the second member to urge it into engagement with the tube wall, wherein the said portions of the second member are disposed at an angle to each other.

10. An assembly as claimed in claim 9 wherein the angle is 90 , 45', 120' or 145".

11. An assembly as claimed in claim 9 or 10 wherein two said second members are provided, one disposed radially

12. An assembly as claimed in claim 9, and forming part of a T-joint, the aforesaid two tubes lying at right-angles to each other and a third tube lying coaxial with one of the said tubes, said third tube and said one of said first tubes being united by a straight second member and said third tube and said one of said first tubes each being connected to the second of the two tubes by second members each having a 90 bend and each having at least that portion which engages the third member and the one of the first tubes of circular cross-section so that before final tightening of the fasteners in the third tube and the one tube the second tube can be pivoted relative to them.

13. An enlarged assembly comprising an assembly as claimed in claim 9, in combination with a third tube adjacent pairs of said tubes being connected by respective second members.

14. An enlarged assembly as claimed in claim 13, wherein two of said three tubes lie in a common plane and the third lies at right angles to that plane.

15. An enlarged assembly as claimed in claim 14, wherein said two tubes lie at right angles to each other.

16. An enlarged assembly including an assembly as claimed in claim 9, wherein the total number of tubes is four or more, at least two thereof are in-line and at least one lies at right angles to the two which are in line, the or each tube which lies at right angles to the or a pair of in-line tubes being pivotable about the mutual axis of the in-line tubes before final clamping of the second members by the first members.

17. An enlarged assembly as claimed in claim 16 wherein there are four tubes only arrangeable in a rectangular cross-shaped array in a common plane, each of the tubes being pivotable about the common axis of the adjacent pair of in-line tubes.

18. A joint assembly between two or more tubes substantially as hereinbefore described with reference to the accompanying drawings.