TUBULAR STRUCTURES AND JOINT FOR CONNECTING TUBULAR MEMBERS

Abstract: The invention provides a tubular structure comprising a first tubular member (1) having slots (2) in the peripheral wall thereof and a second tubular member (3) and end por­ tion (4, 8 13) of which has been flattened and formed to pro vide hook portions (5, 6) adapted to cooperate with the slots (2) to connect the tubular members together. The invention also provides a method of connecting tubular members which comprises providing first and second tubular mem­ bers (1, 3) as aforesaid and engaging the hook portions (5, 6) of the second tubular member (3) in the slots (2) of the first tubular member (1). The invention further provides a tu­ bular member (3) at least one end portion (4, 8, 13) of which has been flattened and formed to provide hook portions (5, 6) as well as the method of producing such a tubular member.

Description: TUBULAR STRUCTURES AND JOINT FOR AND METHOD OF CONNECTING TUBULAR MEMBERS This invention relates to tubular structures and to a joint for and method of connecting tubular members. There are many occasions when it is desired to connect tubular members together, e.g. so that they extend at right angles to one another. Usually the tubular members are connected together by connector means such as clamping means adapted to embrace and clamp the tubular members which are to be connected together. Such connector means are usually expensive to produce and awkward in use so that it normally requires at least two people to erect a tubular structure such as a rack system for the hanging of clothes or the like. The present invention has as its object to provide a tubular structure and a joint for and method of connecting tubular members which is both simple and robust, and which obviates the need for separate and expensive connector means. The present invention provides a structure comprising a first member having at least one slot in the peripheral wall thereof and a second tubular member having an end portion thereof flattened and formed to define at least one hook portion adapted to cooperate with said at least one slot to connect the tubular members together. The first member may be constructed of rigid sbeet material or may be a tubular member. The present invention also provides a tubular member for forming a tubular structure, at least one end portion of which has been flattened and formed to provide at least one hook portion. The present invention further provides a method of connecting members to form a structure, the method comprising providing a first member having at east one slot 5 n the peripheral wli thereof, providing a second tubular member and end portion of which has been flattened and formed to provide at least one hook portion adapted to cooperate with said at least one slot, and engaging said at least one hook portion with said at least one slot to connect the members together. The present invention yet further provides a method of producing a tubular member having at least one hook portion at at least one end thereof, the method comprising flattening at least one end portion of a tubular member and forming the flattened end portion to provide at least one hook portion. The first member may be a tubular member which forms, or is to form, an upright of the tubular structure and said at least one slot may extend longitudinally thereof. Preferably the first tubular member has a plurality of aligned, longitudinally-extendina slots at spaced intervals along the length thereof so that the hook portion of the second tubular member can be engaged therewith at a selected position along the length thereof. Preferably the flattened end portion of the second tubular member is formed to provide two spaced hook portions adapted to engage two longitudinally spaced slots in the first tubular member so as to prevent any possibility of the second tubular member turning or twisting relative to the first tubular member. The two hook portions are preferably such that they can be inserted into a pair of spaced slots in the first tubular member and then moved into a force or friction fit with the wall of the first tubular member at one end of each of the slots. To enable the second tubular member to be mounted between two first tubular members, one or each end of the second tubular mem-rnr may be Sc flattened and formed that the flattened end portion at at least one end of the second tubular member can be inserted into the slot or slots in the adjacent first tubular member to such an extent that the flattened end portion at the other end of the said second tubular member can be engaged with the slot or slots in the other of the first tubular members when the pair of first tubular members are spaced apart a distance at which the slots therein will be engaged by the hook portions at opposite ends of the second tubular member. Whilst it is convenient to use tubing of circular cross-section for the first and second tubular members, it is possible to use tubing of other section. Indeed, if the second tubular member has to carry relatively large loads, it is convenient to form it from tubing of substantially elliptical cross-section. However, assuming the major axis of the tubing will be greater than the diameter of tubing of circular cross-section normally used, the elongation created by flattening the elliptical tubing parallel to the major axis thereof will mean that the two hook portions will be spaced incorrectly relative to the slots in the first tubular member if these have been standardised to accept the normal tubing of circular cross-section, and if the hook portions are formed without removinq the curved and smooth transition between the two flattened tubing walls at the opposed lateral side marqins of the flattened end portion. If this transition were removed, there would be a danger of the walls of the flattened end portion opening out with a consequential difficulty of engaging the slots in the first tubular member. This problem may be obviated by forming a swage or indentrt o:l n oa-hi rl flattened end. portion of the second tubular member whereby the lateral dimension of the flattened end portion is reduced to the required size. The hook portions can then be formed as before. Alternatively, a central and longitudinally extending slot may be formed in each flattened end portion, and then the end squeezed, either before or after the hook portions are formed, in the direction of the major axis of the tubing, again to achieve the desired dimension. According to a preferred embodiment of the present invention the tubular structure comprises a rack assembly having a plurality of said first tubular members, e.g. arranged at four corners of the assembly, said first tubular members forming uprights of the assembly and each having two or more pluralities of slots at different angular positions, e.g., at 900 or 1800 from one another, therearound, the slots of each plurality being aligned longitudinally-extending slots provided at spaced intervals along the length of the upright, and a plurality of second tubular members which form cross-members of the assembly and the hook portions of which are engaged with selected slots in said uprights to connect the uprights together. At least one cross-member may be provided, e.g., which extends between a pair of opposed intermediate uprights, which forms a hanging rail for the hanging of goods such as clothes on clothes hangers. The assembly may comprise at least one shelf supported on two or more said cross-members. The or each said shelf may be of sheet metal construction and may have a depending flange therearound which is relieved at the four corners of the shelf so that the flange can be engaged over the supporting cross-members to locate the shelf on the cross-members. The assembly may further comprise one or more cross-members W71 which are of sheet metal construction and which are provided with hook portions at each end thereof adapted to engage the slots in said uprights. Said sheet metal cross-members may form a plinth at the bottom of the assembly and/or a lintel at the top of the assembly to improve the appearance of the assembly. Also, if desired, one or more sheet metal crossmembers may be provided, e.g., at the top of the assembly, which has spaced along the length thereof laterally extending slots adapted to receive the hook portions of a said cross-member such as a cross-member which is to form a hanging rail. The or each said slotted sheet metal cross-member may have spaced at intervals along the length thereof pluralities of laterally aligned, laterally spaced and laterally extending slots adapted to receive the hook portions of a said cross-member. The invention will be more particularly described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a fraqmentary exploded perspective view of a joint for connecting tubular members according to the present invention, Figure 2 is a fragmentary side view of a partially formed first alternative component for the joint of Figure 1, Figure 3 is a diagrammatic end view from the right of Figure 2, Figure 4 is a view similar to Figure 1 but showing the component completely formed, Figure 5 is a fragmentary side view of a partially formed second alternative component for the joint of Figure 1, Figure 6 is a view similar to figure 5 but showing a subsequent stage of formation, Figure 7 is a perspective view of a partly asenibled tabular structure according to the present invention, and Figure 8 is a similar perspective view of the tubular structure of Figure 7 assembled, and superimposed thereon additional components of a rack assembly shown in portions that they might occupy in the completed rack assembly, certain parts being cut away for clarity. Referring to Figure 1 of the drawings, it will be seen that there is provided a first tubular member 1 of circular cross section having in the peripheral wall thereof a series of longitudinally extending slots 2 spaced along the length thereof, and a second tubular member 3 of circular cross section, and end portion 4 of which has been flattened and formed to provide a pair of spaced hook portions 5, 6 adapted to cooperate with a selected adjacent pair of slots 2 to connect the tubular members 1 and 3 together. The hook portions 5 and 6 are so dimensioned that they can be inserted into adjacent slots 2, and the slots 5a and 6a defining the hook portions 5 and 6 are of such a width that when the hook portions 5 and 6 are inserted into adjacent slots 2 and the hook portions 5 and 6 are moved downwardly in the aspect of the drawing, the slots Sa and 6a will make a force or friction fit with the wall of the tubular member 1 at the lower ends of the adjacent slots 2 with which the hook portions 5 and 6 are engaged. The end portions 4 of the tubular member 3 is preferably flattened to an extent greater than that necessary to form the hook portions 5 and 6 and the cut-out 7 between the hook portions 5 and 6 extends longitudinally of the tubular member 3 to an extent greater than that necessary to enable the hook portions 5 and 6 to engage with adjacent slots 2 in the first tubular member 1 so that the end portion 4 can be inserted into adjacent slots 2 in the tubular member 1 to an extent greater than that required to engage the hook portions 5 and 6. This enables the tubular member 3 to be engaged between a pair of tubular members 1 which are spaced apart by a distance such that they can be correctly engaged by hook portions 5 and 6 at opposite ends of the tubular member 3 without any necessity for moving the spaced tubular members 1 further apart. This facility is useful when it is desired to insert a further tubular member 3 between a pair of tubular members 1 which are already connected together by one or more tubular members 3. If desired, the tubular member 1 may have one or more further series of spaced slots 2, e.g. as illustrated at 2a in the drawinq, so as to enable the tubular members 3 to be engaged therewith at other radial positions therearound. Also, if desired, screw or other locking means may be provided for locking the hook portions 5 and 6 in engagement with the slots 2 in the tubular member 1, although in general this will not be necessary, particularly where the hook portions 5 and 6 are in interference fit with the wall of the tubular member 1 at the bottoms of the slots 2. The joint of the present invention is particularly applicable to tubular members of circular section which are formed from a suitable metal such as steel or aluminium although it can also Xe applied to tubular members wherein one or both of the tubular members is non-circular in cross-section and to tubular members which are formed from materials other than metal but which are capable of being flattened and formed to provide the hook portions 5 and 6. Thus, for example, the tubular members could be formed from a suitable plastics material. One ins(.anc where tubular members of non-circular cross-section may be employed is where the tubular member 3 has to carry relatively large loads. In this case, it is desirable to provide the necessary load-bearing capability by using a tube of elliptical cross-section for the tubular member. However, one of the problems associated with the use of such a tube is that when the end is flattened parallel to the major axis the resulting elongation in the direction of that axis is greater than that occasioned by the flattening of a tube of circular cross-section as in Figure 1, assuming the major axis of the elliptical section tube is greater than the diameter of the circular section tube. Therefore in order to be able to standardise on the upright tubular member 1, it is necessary to vary the formation of flattened ends of tubes of elliptical cross-section used for the tubular member 3 on the basis that two hook portions 5 and 6 are to be provided as before, rather than a single hook portion. Such a tubular member 3 is shown in Figures 2 to 4 of the accompanying drawings, Figure 2 showing a partially formed flattened end portion 8. In the flattening process, a swage or indentation 9 of predetermined dimensions is formed centrally of the end portion 8, and extending longitudinally of the tubular member, the swage tapering from the end of the latter. The result of forming the swage 9 as the end portion is flattened is that the dimension A (Figure 2) is reduced to the same as the similar dimension of the tubular member 3 of Figure 1. Thus, when the hook portions 5 and 6 are formed (Figure 4) they can be received in the selected slots 2 of the standard upright tubular member 1 of Figure 1. The hook portions 5 and 6 and slots Sa and 6a are formed by stamping and it will be seen that the cut-out 7 removes the majority of the swage 9, and that the otherwise inclined outer ends 11 of the hook portions 5 and 6 are trimmed in the stamping operation. A further alternative tubular member 3 formed from tubing of elliptical cross-section is shown in Figures 5 and 6, Figure 5 showing the member after a first stage of formation, and Figure 6 showing the member after a subsequent stage of operation. In this embodiment, no swage is formed but merely a cut-out 12 from the end of the tubular member as the end portion 13 is flattened. This means that the dimension B is too great relative to the spacing of the slot 2 on the tubular member 1 of Figure 1. Therefore, the next stage of formation is to reduce this dimension to the required size by squeezing the end portion 13 in the direction of the major axis of the tubular member 3 so that the shape of Figure 6 is achieved, this being generally similar to the overall shape of the tubular member 3 shown in Figure 4. Finally the hook portions 5 and 6, slots 5a and 6a and the cut-out 7 are formed by a stamping operation, these being shown in broken lines in Figure 6. At the same time, the otherwise inclined outer ends 14 are trimmed as in the embodiment of Figures 2 to 4. The alternative tubular members 3 of Figures 2 to 6 are employed in precisely the same manner as the tubular member 3 of Figure 1 and, as already mentioned, are fully compatible with the upright tubular members 1, and are able to accept greater loads. In these alternatives, it will be appreciated that the curved and smooth transition 15 at opposed sides of the respective flattened end portions 8 and 13 is preserved which helps to minimise the tendency of the ends to open out which would create difficulty in engaging the hook portions 5 and 6 with the slots 2. If this were not a desirable feature, then the hook portions 5 and 6 could be stamped or otherwise formed at the required relative spacing from the flattened end portions 8 and 13 without the need for any of the extra stages of formation described. Tubular members as shown in Figures 1 to 6 and joints as shown in Figure 1 are utilised in the tubular structure shown in Figures 7 and 8 Figure 7 shows an intermediate stage in the assembly of a rectangular structural framework for use as a modular part of a stock rack assembly in a shop, store or warehouse. The framework shown, comprising a tubular upright member 21 at each of four corners, defines one bay of the rack assembly, and is formed from two parallel rectangular end frames 22 connected by four tubular bay tie members 23 at top and bottom, front and rear. Each end frame 22 comprises a pair of spaced apart upright members 21 connected at the top by a top frame tie 24 and at the bottom by a bottom frame tie 25. The upright members 21 are similar to the tubular member 1 of Figure 1, except that the slots 2 are in four sets at 900 angular spacing about the member. Each frame tie 24 and 25 is of sheet metal construction, and each end terminates in two spaced hook portions, formed e.g., by cutting or stamping the sheet metal, which engage the slots in the uprights 21 in like manner to the engagement of the hook portions 5 and 6 with the slots 2, as already described with reference to Figure 1. The bay tie members 23 are similar to the tubular members 3 of Figures 1 to 6 and engage the slots in uprights 21 as the tubular members 3 engage the slots 2 in the tubular member 1. The hook portions of the tie members 23, 24 and 25 are a force fit witi the walls of the tubular uprights 21 at the ends of the slots therein, so as to form a relatively permanent (although separable when required) connection. The top frame tie 24 and bottom frame tie 25 are provided with horizontally extending flanges 28 on each side thereof, for supporting shelves 29, as shown in Figure 8. Adjustable support members 30, similar to the top frame ties 24 except that their hook portions are a loose fit in the slots of the uprights 23, extend between the uprights of each end frame 22 at any selected height. To enable the adjustable support members to be mounted between the uprights, their hook portions 31 can be received into the slots of one upright to such an extent that the hook portions on their other ends can be aligned with the slots of the other upright, before the hook portions at both ends are moved into engagement with their respective slots. The top frame ties 24 and adjustable support members 30 are also provided with vertically aligned pairs of slots 32 at spaced intervals along their lengths. An adjustable tubular hanging rail 33, similar to the tubular members 3 of Figures 1 to 6, is shown engaged with opposite pairs of slots in opposite support members 30, and others can similarly be engaged with opposite pairs of slots in the uprights 21 or in the top frame ties. Further sheet metal cross-members are provided by an adjustable shelf back 36, which extends between the two rear tubular upright members 21 at the back of the rack assembly bay, a pair of adjustable divider supports 38 each having one pair of vertically aligned slots at its mid-length, which extend between the two uprights 21 of each end frame 22, and an adjustable shelf divider 37, which extends between the stairs of slots in the divider supports. Each of these adjustable sheet metal cross-members, including the adjustable support members 30, has terminal pairs of hook portions 31 formed thereon, e.g., by cutting or stamping, identically as regards their loose engagement with the walls at the ends of the slots in the tubular upright members and in the sheet metal members and as regards the extent to which they can be inserted into the slots to allow the hook portions at the other ends of the crossmembers to be aligned and engaged with their respective slots. A further adjustable sheet metal cross-member is provided by end panel 39. This panel has an inturned flange therearound which is relieved at the four corners thereof to permit the panel to embrace the two upright members 21 of an end frame 22. Four hook members 41 are mounted on the inner face of the panel to engage slots in the upright members. It can thus be seen that the hook portions provided in the flattened and formed end portions of the tubular members 3, 23 and 33 and the slots provided in the tubular members 1 and 21 and in the sheet metal members 24, 30 and 38 can be utilized not only for connecting the tubular members together but also for connecting the tubular members to other components provided with similarly dimensioned hook portions and slots, thus showing great versatility which is particularly useful in the construction of, for example, rack assemblies as described, utilising tubular members which are provided with integrally formed hook portions without the need to attach further parts to make the joints. It will readily be appreciated from a consideration of the drains and of the preceding description that the present invention provides a joint which is both simple and robust and which enables tubular members to be readily and quickly assembled to other tubular or sheet metal members. The present invention is particularly suited to tubular structures such as rack assemblies as hereinbefore described for the hanging of clothes on clothes hangers or for similar applications where goods are suspended by hooks and/or stored on shelves but is also suited to other tubular structures such as to scaffolding.

Claims: CLAIMS: 1. A tubular structure comprising a first member having at least one slot in a wall thereof and a second member having at least one hook portion adapted to cooperate with said at least one slot to connect the members together, characterised in that the second member is a tubular member having an end portion thereof flattened and formed to define the at least one hook portion. 2. A structure according to claim 1, wherein the first member is constructed of rigid sheet material. 3. A tubular structure according to claim 1, wherein the first member is a tubular member. 4. A tubular structure according to claim 3, wherein the first tubular member forms an upright of the tubular structure and said at least one slot extends longitudinally thereof. 5. A tubular structure according to claim 3 or claim 4, wherein said first tubular member has a plurality of aligned longitudinally-extending slots therein at spaced intervals along the length thereof. 6. A tubular structure according to claim 5, wherein said first tubular member has two or more pluralities of slots at different angular positions there around. 7. A tubular structure according to claim 6, wherein said pluralities of slots are angularly displaced 900 or 1800 from one another. 8. A structure according to any one of the preceding claims, wherein the flattened end portions of the second tubular member is formed to provide two spaced hook portions adapted to engage two longitudinally spaced slots in the first member. 9. A structure according t-o claim 8, wherein said hook portions are such that they can be inserted into a pair of spaced slots in the first member and then moved into a force or friction fit with the wall of the first member at one end of each of the slots. 10. A structure according to any one of the preceding claims, wherein said second tubular member is mounted between a pair of said first members, one or each end of the second tubular member being so flattened and formed that the flattened end portions at at least one end of the second tubular member can be inserted into the slot or slots in the adjacent first member to such an extent that the flattened end portion at the other end of the said second tubular member can be inserted into the slot or slots in the other of the first members when the pair of first members are spaced apart a distance at which the slots therein will be engaged by the hook portions at opposite ends of the second tubular member. 11. A structure according to any one of the preceding claims, wherein the flattened and formed end portion of the second tubular member has been formed by forming a swage or indentation in the flattened end portions to reduce the lateral dimension thereof and then forming the at least one hook portion. 12. A structure according to any one of the preceding claims 1 to 10, wherein the flattened and formed end portion of the second tubular member has been formed by forming a central and longitudinally extending slot in the flattened end portion and the flattened end portion squeezed, either before or after the forming of the at least one hook portion, to reduce the lateral dimension of the flattened end portion. 13. A tubular structure according to any one of the preceding claims, wherein the or each said hook portion is so formed that the curved and smooth transition between the two flattened tubing walls at each of the opposed lateral side margins of the flattened end portion is preserved. 14. A tubular structure according to any one of claims 11 to 13, wherein said second tubular member is substantially elliptical in cross-section and said flattened end portion is flattened parallel to the major axis of said cross-section. 15. A tubular structure according to any one of claims 3 to 7, or any one of claims 8 to 14 appendant to any one of claims 3 to 7, wherein the tubular structure comprises a rack assembly having a plurality of said first tubular members forming uprights of the assembly and each having two or more pluralities of slots at different angular positions therearound, the slots of each plurality being aligned lonitudinally-extending slots provided at spaced intervals along the length of the upright, and a plurality of second tubular members which form cross-members of the assembly and the hook portions of which are engaged with selected slots in said uprights to connect the uprights together. 16. A tubular structure according to claim 15, comprising at least one cross-member which forms a hanging rail for the hanging of goods. 17. A tubular structure according to claim 15 or 16, comprising at least one shelf supported on two or more cross-members. 18. A tubular structure according to claim 17, wherein said shelf is of sheet metal construction and has a depending flange therearound which is relieved at the four corners of the shelf so that the flange can be engaged over the supporting crossmembers to locate the shelf on the cross-members. 19. A tubular structure according to any one of claims 15 to 18, comprising at least one crossmember which is of sheet metal construction and which is provided with hook portions at each end thereof adapted to engage the slots in the uprights. 20. A tubular structure according to claim 19, wherein said sheet metal cross-member has spaced along the length thereof laterally extending slots adapted to receive the hook portions of a said cross-member. 21. A tubular structure according to claim 20, wherein said sheet metal cross-member has at spaced intervals along the length thereof pluralities of laterally aligned, laterally spaced and laterally extending slots adapted to receive the hook portions of said cross-member. 22. A tubular member for use in forming a tubular structure, characterised in that at least one end portion thereof has been flattened and formed to provide at least one hook portion. 23. A tubular member according to claim 22, wherein said at least one end portion has been flattened and formed to provide two spaced hook portions. 24. A tubular member according to claim 22 or 23, wherein said at least one end portion has been flattened and formed with a swage or indentation to reduce the lateral dimension thereof and then formed to provide said at least one hook portion. 25. A tubular member according to claim 22 or 23, wherein said at least one end portion has been flattened, formed with a central and longitudinally extendinq slot and squeezed, either before or after the forminq of the at least one hook portion, to reduce the lateral dimensions of the flattened end portion. 26. A tubular member according to any one of claims 22 to 25, wherein the or each said hook portion is so formed that the curved and smooth transition between the two flattened tubing walls at each of the opposed lateral side margins of the flattened end portion is preserved. 27. A tubular member according to any one of claims 22 to 26 wherein the tubular member is substantially elliptical in cross-section and said at least one end portion is flattened parallel to the major axis of said cross-section. 28. A method of connecting members to form a structure, the method comprising providing a first member having at least one slot in the peripheral wall thereof, providing a second member having at least one hook portion adapted to cooperate with said at least one slot, and engaging said at least one hook portion with said at least one slot to connect the members together, characterised in that the second member is a tubular member and the at least one hook portion is defined by a flattened and formed end portion of the tubular member. 29. A method of prodicing a tubular member having at least one hook portion at at least one end thereof, the method comprising flattening at least one end portion of a tubular member and forming the flattened end portion to provide at least one hook portion. 30. A method according to claim 29; which comprises forming the flattened end portion to provide two spaced hook portions. 31. A method according to claim 29 or 30, which comprises forming the flattened end portion with a swage or indentation to reduce the lateral dimension thereof and then forming the flattened end portion to provide the at least one hook portion. 32. A method according to claim 29 or 30, which comprises providing a central longitudinally extending slot in the flattened end portion and squeezing the flattened end portion, either before or after the forming of the at least one hook portion, to reduce the lateral dimension thereof. 33. A method according to any one of claims 29 to 32, which comprises so forming the at least one hook portion that the curved and smooth transition between the two flattened tubing walls at each of the opposed lateral side margins of the flattened end portion is preserved

Inventors: DEACON PAUL, THORNBORROW, JOHN W. T. K.
Applicants: J.R. COMMERCIAL ENTERPRISES LIMITED
Application year: 1983
Main classification: E04G7
IPC codes: F16B7