GB2043200A - Joints for tubular frameworks - Google Patents

Abstract

A tubular frame comprising tube portions (20) each having a bore which is of a star-like configuration by virtue of diametral clamping surfaces (30), and connectors (11) to connect the tube portions (20) together, each connector (11) having connecting spigots (12) with a cross-section complementary to the bores of the tube portions (20), wherein, in an initial relative rotary position of each tube portion (20) and cooperating connecting spigot (12) adopted for assembly the connecting spigot (12) can be freely inserted in the bore, subsequent rotation of the tube portion (20) about its axis with respect to the connecting spigot (12) securing the tube portion (20) to the spigot (12) by causing the clamping surfaces (30) of the bore of the tube portion (20) to fit tightly against edge regions (39) of the connecting spigot (12), the outer profile (21) of each tube portion (20) is generally circular but has longitudinal ribs (23) thereon to form radial abutment flanks for wall and/or shelf panels and for engagement by a tool (44) for rotating the tube portion (20), each of the clamping surfaces (30) in the bore is radially aligned with a respective one of the ribs (23) and each connecting spigot (12) of each connector (11) has a metal core with a sheathing of elastically flexible plastics material defining the edge regions (39) of the connecting spigot (12) which cooperate with the clamping surfaces (30) of the tube portion (20). <IMAGE>

Description

SPECIFICATION Tubular frameworks The invention relates to tubular frames for forming platforms, counters, shelves, cupboards and like articles.

Such a tubular frame may comprise tube portions, the tube portions having an angular outer profile for supporting selectively insertable wall and/or shelf panels and a bore which is of a star-like configuration by virtue of diametral clamping surfaces, and connectors to connect the tube portions, the connectors having connecting spigots with cross-section complementary to the bores of the tube portions.

Connection between one of the tube portions and one ofthe connectors is effected in a particular manner in that, in a starting rotational position of the tube portion, the tube portion can befitted overthe angular cross-section of the connecting spigot because the bore has clearance from the angular cross-ection. This is the free, assembly position in which the tube portion can be freely fitted onto or pulled off the connecting spigot. The tube portion may be easily fixed on the connecting spigot by rotating it about its axis relative to the spigot to cause the clamping surfaces which constrict the inner profile to be pressed firmly against edge regions of the connecting spigot. This results in the tube portion moving to a final secured position on the connector, to give the frame stability in the erected condition.

It has been previously proposed to use tube portions with a tetragonal bore for such a tubular frame (German Gebrauchsmuster No 72 02 922), wherein, in the erected condition, the tetragonal tubes point downwardly with a tip or corner and their side surfaces form support surfaces for correspondingly bevelled wall or bottom panels. The connecting spigots of the associated connectors (German patent specification No 813 634) are of a similartetragonal cross-section, with the connecting spigot corners being set diagonally and the tetragonal tubes being pushed thereoverwith a downwardly facing surface, because in that case the free spaces for receiving the edges of the spigots of the connectors are disposed at the corner points of their tetragonal bore.The important clamping surfaces lie in the bore of the tetragonal tubes against the side surfaces and, in the final fixed position of the tube portions, when the latter are rotated axially through 45", come into the above-mentioned diagonal position where they serve with thier outer surfaces for supporting the wall or bottom panels. Such an arrangement suffers from the disadvantages that the vertical position of the bottom panels on such tetragonal shaped members is not clearly defined, and the fact that the edges of the bottom panels must be cut diagonally for full contact with the support members.Although the loading is applied predominantly at the edges of the tetragonal tubes, the clamping surfaces of the tubes, which fit firm ly to the spigot edges of the connectors, are set back relative thereto, whereby the considerably shorter effective lever arm lengths in the shaped member cause the rotational moments which are applied to the corners in the event of a loading on the panel and which act in the direction of release of the tube portions to be slightly greater than the retaining rotational moments of the connecting spigots, which moments occur at the diagonal clamping surfaces which are radially further back.Because the assembly operation is made more difficult and the material is subjected to an excessively heavy loading, it is also impossible, by suitable cross-sectional adaptation, to compensate for this simply by having a larger press fit in respect of the connecting spigots against the clamping surfaces. A particular problem which arises in this respect is reliable vertical positioning of wall panels on a tetragonal tube of this kind.

According to the invention there is provided a tubular frame comprising tube portions each having a bore which is of a star-like configuration by virtue of diametral clamping surfaces, and connectors to connect the tube portions together, each connector having connecting spigots with a cross-section complementary to the bores of the tube portions, wherein, an initial relative rotary position of each tube portion and coopoerating connecting spigot, which relative rotary position characterises a free assembly position, the connecting spigot can be freely inserted in the bore, subsequent rotation of the tube portion about its axis with respect to the connecting spigot securing the tube portion to the spigot by causing the clamping surfaces of the bore of the tube portion to fit tightly against edge regions of the connecting spigot, the outer profile of each tube portion has a circular base contour with longitudinally extending and projecting ribs thereon to form radial abutment flanks for wall and/or shelf panels and for a tool for rotating the tube portion to engage, each of the clamping surfaces in the bore is radially aligned with a respective one of the ribs, between which ribs are form-elastic tube wall zones with arcuate portions of the circular profile and each connecting spigot of each connector has a metal core with a sheathing of elastically flexible plastics material, which defines the edge regions of the connecting spigot which cooperate with the clamping surfaces of the tube portion.

Such a tubular frame, while it can be easily assembled and dismantled, can remain reliably connected together and permit wall and shelf panels to be easily and quickly fitted into place.

By means of their radial flanks, at a clearly defined position in the direction of the height of the frame, the ribs define shoulders for supporting the wall or shelf panels, although a basically circular tube is used, for reasons of good elasticity. The circular outer profile remains only in the zones of the tube which remain between the ribs and which only have an elastic action by virtue of their form, when the connecting spigots of the connectors are clamped and released, because the clamping surfaces in the bore are disposed in alignment with the axial ribs on the outer profile, for which purpose the walls in the tube wall regions of the axial ribs are strengthened on the inside. The clamping surfaces are more desirably of a flat configuration, in this arrangement.

This results in the bore of the tube being of a star-like configuration which is rotationally displaced relative to the outer profile configuration defined by the axial ribs. By virtue of this alignment of the axial ribs and the clamping surfaces, the position at which the panels are supported on the axial ribs is very close to the position at which the tube is clamped firm to the connector. This firm clamping action may be achieved in particular by virtue of forming the angular cross-section from the plastics material, if a metal core which provides for stability is embedded therein.In this arrangement, it is particularly advantageous for the core in turn to be of a suitable angular profile which is rotationally displaced relative to the outer angular cross-section of the connecting spigots so that the regions of the edges of the connecting spigots, which are formed by the angular cross-section, have greater thicknesses of plastics material, which have a particularly significant effect on their elastic flexibility and which can produce a particularly effective pressing action to provide for firm clamping. The angular profiles of the core, which are rotationally displaced for this purpose can, nonetheless, provide for a sufficient degree of stability in respect of shape, in this combination of materials.

Even if a circular tube cross-section in the zones of the tube wall which are disposed between the axial ribs is found to be advantageous, it is also possible for these regions to have arcuate portions of a shape which differs from a circular configuration, whether such regions are of a concave or a more convex configuration, or whether such regions still have therein edges which can be utilised for supporting the wall or shelf panels.

It is desirable for the ribs to be provided in the region of their positions of attachment to the tube with undercut portions, for which purpose the ribs are for example of an Q-shaped configuration. The ribs with their undercut portions may now be used in a highly advantageous mannerforthe mounting of cover strips or retaining springs, because bent edge portions of such components engage into the undercut portions of the ribs and thereby provide for axial and radial positioning of the components and the object carried thereby. In this way, for example retaining springs may be provided with clip ends which engage around the edges of bottom panels.

Other retaining springs may be provided with lugs or table which either engage into the undercut portions or come to lie at a distance in front of the ribs, which distance corresponds to the wall thickness, and thus provide a support means for the panels to be assembled, on the side opposite the ribs. As can be seen, such retaining springs and strips can permit simple and quick fitting of the panels. These means can be cheap to produce and compact to store.

It is also possible for intermediate panel carriers for additional shelf panels to be fitted in the region of the tube portions, without requiring the use of connectors at that point. The intermediate panel carriers are arranged in the tube wall zones which are of a circular configuration and they are used at the same time for supporting vertical wall panels on the inside, because, with their boundary edges, they form cooperating abutment surfaces which are directed towards the ribs and which are spaced from the ribs at a distance corresponding to the thickness of the panels. Suitable forms of such intermediate panel carriers are simple tri-angular plate members which carry an offset or bent assembly hook portion on one surface, which hook portion can be fitted in a hole in the wall in the tube portion.On the other side, it is sufficient to provide a support leg portion whose axis extends parallel to the axis of the tube portion.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 shows a storage unit having a tubular frame according to the invention; Figure 2 shows a perspective exploded view of a tube portion and a corner connector of a tubular frame according to the invention, together with an assembly tool; Figure 3 shows a cross-sectional view through the end of the tube portion of Figure 2 with a connecting spigot of the connector inserted therein, in the free, assembly position in which the components are capable of relative movement, with a shaped holder for a glass shelf shown engaged on the outer profile, and a cover panel shown engaged by way of a retaining clip;; Figure 4 is a view corresponding to Figure 3 but with the components in the secured position relative to each other, and with a retaining spring for a shelf panel and a wall panel shown on the outer profile; Figure 5 shows a perspective view of the retaining spring shown in Figure 4; Figure 6 shows a perspective view of a tube portion with a cover strip which can be fitted to and removed from the tube portion by a snap action; Figure 7shows a side view of a corner connector before assembly thereof; Figure 7a shows a view of the connector of Figure 7, on an enlarged scale and in cross-section taken on line Vlla-Vlla of Figure 7; Figure 8 shows a side view in section taken on line VIII-VIII of Figure 10 of an intermediate panel carrier which is mounted on a tube portion and which also serves for retaining vertical wall panels;; Figure 9 shows a view of the assembled intermediate panel carrier in section taken on line IX-IX of Figure 10, with such an intermediate panel being shown in section; and Figure 10 shows a view from below in section taken on line X-X in Figure 8, of the connection provided by such an intermediate panel carrier, the intermediate panel carried thereby itself being omitted.

Referring to the drawings, and firstly to Figures 1 and 2, a tubular frame 10 can be used to produce a storage or display unit which is of different configurations in different parts thereof and which can be varied or supplemented as required. The components of the frame structure are tube portions 20 of suitable lengths and connectors 11 which are provided at the junctions of the tube portions 20 and which have two to six connecting spigots 12, according to the particular forms of the junction which they secure. As required, horizontal shelf panels 13 or vertical wall panels 14 can be disposed between the assembled tube portions 20. The panels are dimensioned in accordance with the predetermined lengths of the tube portions, without connectors having to be present and intermediate panels 15 can also be arranged selectively in the longitudinal region of the tube portios 20.

The tube portions 20 have the particular configuration seen in Figures 3 and 4, the outer profile 21 being different to the bore 22. The tube portion is generally in the form of a round tube with four projecting axial ribs 23 disposed on the outer profile 21. The axial ribs 23 project radially beyond a base contour 24 which is of a round configuration. The axial ribs 23 form diametral edges which, by virtue of their flanks or sides 25, form radial abutment surfaces for the panels 13 and 14, as will be seen from Figures 3 and 4. On the outer profile of the tube portion, the axial ribs 23 form a four-armed star configuration.

If the hollow space 26 in the interior of the tube portion is now considered, the above-mentioned round or circular form provides that the bore 22 has longitudinally extending tube wall zones 27 which in themselves comprise circular tube wall arcuate portions. The hollow space 26 in the tube has, in regions 28 of the tube wall between the zones 27, constrictions which are produced by inwardly projecting portions 29 which increase the wall thickness of the tube. The increased-thickness portions 29 form clamping surfaces 30 which are oriented towards the axis of the tube and which are in particular of a flat configuration.The constrictions in the bore 22, which are formed by the increasedthickness portions 29, also give the bore 22 a four-armed star-like cross-sectional configuration in the hollow space 26 in the interior of the tube, which star-like configuration is rotationally displaced through 45" relative to the above-mentioned fourarmed star-like outer profile 21.

As can be seen from Figures 3 and 4, the clamping surfaces 30 are precisely radially aligned with the axial ribs 23 so that the clamping surfaces 30 come to lie as close as possible to the flanks 25 of the axial ribs 23, which carry the loadings of the panels 13 and 14. This is of significance with regard to the action of fixing the tube portions on the connecting spigots 12 of the connectors 11 which have the basic structure shown in Figures 2 to 4 and 7.

In accordance with the function which it is re quired to perform, a corner connector 11 has a number of connecting spigots 12 which are disposed at right angles to each other and which are carried on an intermediate body portion 16 which carries lug portions 17. The lug portions 17 have shoulder surfaces 8 which are provided for abutting against the end faces 31 of the respective tube portions 20, as can be seen from Figure 2. The lug portions 17 are of an outer configuration which corresponds to the outer profile 21 of the tube portion 20. Thus the connectors 11 also carry axial ribs 19 which each extend in a respective common plane, which planes meet at corner points 32 in the three-spigot corner connector 11 shown in Figure 2.By virtue of this arrangement, for the purposes of supporting bottom panels 13 or wall panels 14 which are to be selectively disposed on the frame structrue, the connectors 11 themselves contribute to retaining the panels thereon by their own axial ribs 19. This arrangement also eliminates sharp corners and edges in the tubular frame 10, which could otherwise result in injury.

The structure and form of the connecting spigot 12 is shown in Figures 3 and 4, and Figure 7. The intermediate body portions 16 carry metal cores 33 which, as shown in Figure 7, can project somewhat out of the end of one of the spigot projections 12, in order to simplify manufacture. The actual peripheral surface of the connecting spigot 12 is however formed by a plastics sheathing 34 whose thickness 35 varies greatly in different regions. As can best be seen from Figure 7a, the core 33 is of a tetragonal configuration and is fixed in the body of the intermediate body portion 16. The corners 36 of the tetragonal core 33 face into the intermediate positions with respect to the positions of the axial ribs, as indicated at 19. It is in the corner regions 36 that the sheathing 34 is of its minimum thickness.The maximum thickness 35 of the sheathing 34 is precisely at the middle of longitudinal sides 37 of the tetragonal core 33 and is thus aligned with the respective axial rib 19 provided at that location. At the position where the core 33 is of the minimum height of material, with respect to its axis 38, the plastics sheathing 34 is of its maximum thickness 35; and vice-versa, at the position where the core 33 is of the greatest height of material relative to the axis 38, in the region of the corner points 36, the plastics sheathing 34 is of the minimum thickness.In this arrangement, the plastics sheathing 34 is of a stronger construction, with regard to its abovementioned difference in height, with respect to the core 33, so that, in alignment with the axial ribs 19, there is such a great maximum thickness 35 that the entire connecting spigot 12 has a contour in its sheathing 34 which provides a certain edge-forming or angular profile, although the edge regions 35 are rounded off. Therefore, there is a rounded tetragonal configuration for the connecting spigot 12. The maximum thicknesses 35 are precisely aligned with the axial ribs 19 on the connecting spigot. With regard to its edges, the plastics sheathing 34 is in phase with the axial ribs 19 of the connector, while the tetragonal core 33 is phase-shifted through 45" at its corner points 36, relative to the plastics sheathing 34.

The assembly process will now be described with reference to Figure 2. It should be assumed that the connector 11 is in the inserted position in the tubular frame 10 with its free connecting spigot 12 is in the rotational position shown in Figure 7a, that is to say with the edge regions 39 thereon aligned vertically and horizontally. In this position the tube portion 20 is freely axially movable relative thereto. The tube portion 20 is thus in the rotational position shown in Figure 2, which shows the free, assembly position of alignment of the two components. The clamping surfaces 30 in the bore of the tube portion are aligned with radially inwardly disposed regions 40 of the spigot with a clearance 41 therebetween when the spigot is inserted into the bore of the tube portion by movement in the direction indicated by arrow 42.

In order to secure these components in the connected position, the tube portion 20 must be rotated through 45 relative to the connector 11, as indicated by arrow 43. For this purpose, a tool 44 can be used, the tool 44 having a handle at its free end and, at its working end, a bent or curved portion 45 which can be engaged behind one of the axial ribs 23, while the portion 46 of the tool which is adjacent to the end portion 45 bears against the outside periphery of the tube portion 20. This arrangement thus provides a lever arm length which makes it possible to produce a high-strength connection, with only a small amount of force being applied, because, With the illustrated arrangement, the rounded radially projecting edge regions 39 press laterally against the flat clamping surfaces 30, with the elastic sheathing 34 being deformed.After rotation through 45", the assembly arrives at the final position as between the tube portion 20 and the connecting spigot 12 of the connector, as shown in Figure 4. The radially projecting edge regions 39 are now aligned with the clamping surfaces 30 and thus with the radial ribs 23 of the tube portion 20. The components are now in the fixed position. Excessive elastic amounts of material can now be pressed flexibly or yieldingly into the free hollow spaces 26. The material of the curved tube wall zones 27 can yield elastically. The solid increased-thickness wall portions 29 in the region of the clamping surfaces 30 and the axial ribs 23 aligned therewith remain substantially rigid in this situation. This provides, so-to-speak, a tube which 'breathes' in respective regions thereof, in the connecting operation.The components are dismantled by a reverse rotation or by a further 45 rotation in the same direction.

When the structure of the tubular frame 10 has been formed from the tube portios 20 and the connectors 11, the frame structure can now be selectively fitted with vertical and horizontal panels.

For this purpose, use is made of retaining springs 50 and 51 which are suited to the particular outer profile 21 of the tube portions 20 and whose configuration and mode of operation are shown in Figures 3 to 5.

Forthis purpose, as shown in Figure 4, the axial ribs 23 are provided with undercut portions 47 which act as axial grooves or channels, atthe base portions of the axial ribs, which are at the rounded portion of the tube. An axial rib is therefore then provided with an shaped profile.

The retaining spring 50 shown in Figures 4 and 5 extends approximately over a quarter of the periphery of the tube portion and bears against the zone 48 which is of a round or circular contour, as shown in Figure 5, over a portion 49 of the length of the tube portion, where it is to be used to support panels 13 and 14, as shown in Figure 4. The retaining spring 50 which is formed of sheet metal is cut at its end, thereby forming four tongue portions 52 which, by virtue of bent edge portions 53 which are directed in opposite directions, point towards respective mutually opposite sides, when tongue portions 52 which are disposed one beside the other or which are disposed opposite each other at the ends of the spring are considered. The retaining spring could have more than only two such tongue portions at its ends, and could extend over a longer portion 49 of the tube portion.Because of the mirror-image configuration of the tongue portions 52, the retaining spring 50 can be used in a reversed position. The tongue portions 52 which are towards the outer profile 21 of the tube portion 20 engage by way of their tips or points 55 into the above-mentioned channel-shaped undercut portions 47 of the associated axial ribs 23 and thus ensure that the retaining spring 50 is secured to the tube portion 20, in particular when they are in a condition of subsequently cooperating with the panels 13 and 14. The retaining spring 50 which is clipped into position is displaceable in the undercut portions 47 as in rails in the longitudinal direction of the tube portion, so that the retaining spring can be slid into the selected position in the length of the tube portion.The narrow edge of both a horizontal bottom panel 13 and a vertical wall panel 14 bears against the respective tongue portions 52, as can be seen in Figure 4. One surface of the panels comes to bear against the above-mentioned side or flank 25 of the respective axial rib 23. The respective other tongue portion 52 which faces away from the tube portion 20 provides a cooperating abutment surface 56 on the respective opposite surface of the panels 13 and 14, because the tongue portions are arranged at a spacing from the sides 25 of the axial ribs, corresponding approximately to the thickness 60 of the panels 13 and 14.It will be seen therfore that the tongue portions of one end of a retaining spring 50 serve to support a wall panel 14 while the opposite tongue portions at the other end of the retaining spring serve to secure a bottom panel 13. Buy virtue of this mutual supporting action, the two panels 13 and 14 are reciprocally secured to the retaining spring 50.

In the case of the retaining spring 51 shown in Figure 3, use is made of a sheet metal strip portion which extends over more than a quarter of the periphery of the tube and which includes an Qshaped bent portion 57 which is fitted snapably about the outer contour of an axial rib 23 and thereby secures the retaining spring 51. At at least one of.its ends, the retaining spring 51 is bent over to form a hook 58 which engages over a covering panel 13 at its narrow side and its one surface, and holds it pressed against the outer profile 21 of the tube. The end 59 of the hook is at a spacing, corresponding to the thickness 60 of the panel, above the abutment region in which the panel bears against the arcuate portion of the contour of the tube against which an intermediate portion of the retaining spring 51 lies.

It is also possible, as shown in Figure 6, to use cover strips which extend in the longitudinal direction of the tube portions 20 and which also have to clad only given longitudinal regions of the outer profile 21. The cover strip shown in Figure 6 is intended to serve for surface stiffening of an axial rib 23 and comprises a scratch-proof, corrosionresistant spring steel of an shaped cross-section.

The cover strip 61 can be snapped over a respective one of the ribs 23. This arrangement provides that even if a soft material such as aluminium is used for the tube portion 20, the tube portion 20 can be used as a clothes hanging rail, as shown in Figure 1 in realtion to some horizontal sections, without being marked by the hooks of clotheshangers.

As shown in Figures 8 to 10 it is possible to fit an intermediate panel 15, using an intermediate panel carrier 61. The carrier 62 comprises a small triangular plate member 63 which is shown as seen from below in Figure 10 and which comes to lie with its apex 64, which is suitably rounded, against a desired intermediate vertical position on the tube portion 20, in a round or circular tube wall zone 27. This zone is provided with openings 65 through which a hook portion 66 which is disposed in the region of the apex 64 of the triangular configuration of the plate member 63 and which projects vertically from the top surface of the plate member can be selectively inserted, at the desired position in the height of the tube portion.On the underside, the triangular plate member 63 has a support leg portion 67 which depends in a wedge-like configuration from the surface of the plate member and which, at its wedge end, by virtue of a wedge-shaped recess, forms supporting knife edges 68 which come to lie against the outside surface of the arcuate tube wall zone 27, parallel to the axis of the tube portion, and thereby, in interaction with the hook portion 66 which faces in the opposite direction, provide for the desired horizontal portioning of the triangular plate member 63. A support surface 69 of the member 62 is set down in a step-like configuration and defined by abutment surfaces 70 which are parallel to the sides of the member 62 and which serve as abutments for the edges of an intermediate shelf panel 15 which is to be fitted into position, as shown in Figure 9.The outer sides 71 of the plate member 63 form cooperating abutment surfaces which can be used for positioning wall panels 14. In the manner already referred to many times above, the wall panels are supported along their one longitudinal edge by the sides 25 of the axial ribs 23. At the other side, the wall panels 14aresecured by the above-mentioned cooperating abutment surfaces 71 of the plate members 63 because those surfaces are disposed at a spacing form the sides 25 of the axial ribs, which corresponds to the thickness 60 of the panels. Thus, the intermediate panel carrier 62 serves not only to hold horizontal panels 15 but also for supporting vertical wall panels 14.

It should be noted that the outer profile 21 of the tube portions 20, as indicated in Figure 10 by means of the subsidiary lines 72 and 73 can be positioned in a square whose sides, as can be seed from lines 72 and 73, form tangents to the arcuate tube wall zones 27 and at the same time have points in contact with the tube profile in the region of the axial ribs 23. The above-mentioned square circumscribes the particular profile of the tube portions 20. This is significant with regard to handling and strength, while respecting the requirement for an economical level of material cost.

Further connecting components can also be connected to the outer profile of the tube portions 20, such as base or foundation bars, base support means and a housing for rollers with which an assembled tubular frame is movable. Bottom panels can also be supported directly on the sides of horizontally disposed axial ribs. It is also possible however to use holders 74 for glass panels, as shown in greater detail in Figure 3. These comprise members or elongate bars of H-shaped profile. The limbs 75 of the member enclose a space which can receive an edge of a glass panel. The opposite limbs 76 of the member enclose between them an Q- shaped recess 77 which can be snap-connected over one of the axial ribs 23. For this purpose the limbs 76 are resilient with respect to each other.Desirably, the glass panel holder 74 is formed from flexibly elastic material or rubber-like quality.

As can be seen from the broken lines in Figure 7, the cores 33 which are arranged in an angular configuration relative to each other are fixedly welded together at their abutment locations 78.

Thereafter, the connector 11 with its further components is produced in a common mould by an injection moulding process, from plastics material.

This operation produced both the sheathings 34 and the intermediate body portions 16 with their ribs 19.

In comparison, the tube portions 20 are preferably formed as aluminium extrusions.

The good form-elasticity of the plastics material used for the sheathings 34 of the connecting spigots 12 can in many cases permit the rotary motion, indicated at 43 in Figure 2, to be omitted from the connecting operation. Thus the tube portion 20 can be rotated to its final rotational position with respect to the configuration of the profile of the connector 11 before insertion is effected and the connecting spigot 12 pressed into the bore of the tube portions 20 if this is necessary or desirable in some circumstances.

Claims (15)

1. Atubularframe comprising tube portions each having a bore which is of a star-like configuration by virtue of diametral clamping surfaces, and connectors to connect the tube portions together, and connector having connecting spigots with a cross-section complementary to the bores of the tube portions, wherein, in an initial relative rotary position of each tube portion and cooperating connecting spigot, which relative rotary position characterises a free assembly position, the connecting spigot can be freely inserted in the bore, subsequent rotation of the tube portion about its axis with respect to the connecting spigot securing the tube portion to the spigot by causing the clamping surfaces of the bore of the tube portion to fit tightly against edge regions of the connecting spigot, the outer profile of each tube portion has a circular base contour with longitudinally extending and projecting ribs thereon to form radial abutment flanks for wall and/or shelf panels and for a tool for rotating the tube portion to engage, each of the clamping surfaces in the bore is radially aligned with a respective one of the ribs, between which ribs are form-elastic tube wall zones with arcuate portions of the circular profile and each connecting spigot of each connector has a metal core with a sheathing of elastically flexible plastics material, which defines the edge regions of the connecting spigot which cooperate with the clamping surfaces of the tube portion.

2. Atubularframe according to claims 1, in which a core member of each connecting spigot has an angular profile coaxial with the outer crosssection of the spigot, and edges of the core member are rotationally displaced with respect to edge regions of the sheathing disposed therearound and in the secured position of the tube portion on the spigot are radially aligned with the circular profile tube wall zones of the tube portion.

3. Atubularframe according to claim 1 or claim 2, in which each of the connectors has an intermediate body portion which carries the connecting spigots and has lug portions which are correspondingly arranged in a cross or corner configuration relative to each other, and lug portions have an outer profile to be engaged thereon and ribs which correspond to each other extend in a common plane adjacent lug portions and meet at a cross or corner position.

4. Atubular frame according to any one of claims 1 to 3, in which the longitudinally extending ribs have undercut portions forming longitudinal grooves, at their positions of attachment to the tubes.

5. Atubularframe according to any one of claims 1 to 4, in which the longitudinally extending ribs have an shaped contour.

6. Atubularframe according to any one of claims 1 to 5, including separate cover strips which can be selectively snapped over the longitudinally extending ribs and also extend in the longitudinal direction of the tube portions.

7. Atubularframe according to claim 6, in which the cover strips are of an shaped section.

8. Atubularframe according to claim 4, including retaining spring members adapted to the outer profile of the tube portions and which can be disposed in an annular zone on one of the tube portions to extend along a part of the tube periphery, each spring member having bent edge portions which on the one hand form spring portions which engage into the undercut longitudinal grooves of the ribs and on the other hand form retaining portions to engage wall or shelf panels.

9. Atubularframe according to claim 8, in which a bent edge retaining portion of the retaining spring member forms a clip which engages around the edge of a wall or shelf panel.

10. Atubularframe according to claim 9, in which, when in position, a bent-edge retaining portion of the retaining spring member is arranged at a distance in front of an axial rib, which distance corresponds to the thickness of a wall or shelf panel.

11. A tubular frame according to any of claims 8 to 10, in which the retaining spring member carries at least two tongue portions at each end, of which tongue portions both those which are disposed one beside the other and those which are disposed opposite each other are bent over in opposite directions to each other.

12. Atubular frame according to any one of claims 1 toll, including intermediate shelf carriers which can be arranged externally on the circularprofile tube wall zones of the tube portions and which carry cooperating abutment surfaces facing towards the axial ribs, which cooperating abutment surfaces which distance corresponds to the thickness of the wall or shelf panel.

13. A tubular frame according to claim 12, in which the carrier surface is stepped in a manner corresponding to the edge contour of the intermediate shelf panel for positioning thereof.

14. Atubular frame according to claim 12 or claim 13, in which the intermediate panel carrier comprises a triangular plate member which, on one of its faces, carries a vertical support leg portion which extends with its axis parallel to the axis of the tube portion and on its opposite side, carries an assembly hook portion which extends in the opposite direction to the support leg portion and which can be fitted into an opening in the wall of thetu be portion.

15. A tubular frame substantially as hereinbefore described and illustrated with reference to the accompanying drawings.