STRUCTURE ELEMENT

The subject invention concerns a device for interconnec¬ tion of a first and a second structural element, the first one of which has a wall with a number of slots formed therein, and the second one of which is an open-ended hollow element and is arranged, in the interconnected position, to be secure on the first structural element with its open end turned towards the first structural element. The second structural element houses a fastening device which is anchored in the first structural element in engagement with the slots formed therein and which comprises a gripping member, which is movable in the lengthwise direction of the second structural element and arranged for engagement with the edges of the slots in the first structural element, and means to urge the gripping member to move to effect the interconnection of the two structural elements.

A device of this kind is described e.g. in the Swedish Patent No. 7612579-8. This patent specification describes a coupling element wherein a hook-shaped grip po-rtion extends through one or several recesses formed in a bracket rail and merges into a portion which is guided for displacement inside a profiled bracket section of channel-like or tubular configuration and which, upon its displacement along said profiled bracket, forces the end of the channel-like or hollow profile into engagement against the bracket rail as a result of the wedging effect obtained between a wedge-he screw and the wall of the channel-like or hollow profile wall.

The main object of the invention is to provide an inter¬ connecting device of the kind outlined in the aforegoing which increases the manageability while at the same tiirte providing safe clamping force interconnection-, irrespectively of the cross-sectional configuration of the two structural elements to be interconnected. As a result the elements

may be of circular or square cross-sectional configuration. This purpose is achieved in accordance with the inven¬ tion by the use of a fastening device consisting of two separate parts or units, viz. the gripping member proper and a tightening member which is mounted in the second

* structural element to cooperate mechanically with the gripp¬ ing member. The tightening member is arranged to transfer the tightening force of a tightening screw extending cross¬ wise in relation to the second structural element, to a tightening force acting on the gripping member in the length¬ wise direction of the second structural element, i.e. trans¬ versely with regard to the first structural element.

In accordance with the characterizing features of the invention the tightening member forms a knee lever which is pivotally mounted in the second structural element. One arm of the knee lever extends in the lengthwise direction of the second structural element and is affected by the tightening screw, which abuts against a stationary part of the second structural element while the other arm of said knee lever extends in the transverse direction of the second structural element and, in its operative position, engages the gripping member. Owing to this arrangement the required re-direction of the tightening force is obtained. Furthermore, the second structural element preferably is formed in one side with a recess which opens towards the coupling end of the element and which is dimensioned to allow reception therein from the exterior of the structura element and in the crosswise direction thereof of the gripp¬ ing member for insertion of the latter in said direction into the inner cavity of the structural element for engage¬ ment with the tightening member. A channel is formed in the tighening member through which the hook member may pass to assume its position of engagement, in which position abutments formed on the gripping member and on the tightenin member, respectively, are juxtaposed relative to one another so as to enable interengagement of the gripping member and

the tightening member while the gripping member is inserted inside the first structural element. Owing to this arrange¬ ment, the two structural elements may be interconnected in a very simple manner in that the gripping member may be placed separately in its position of engagement in the associated slot in the first structural element prior to the assembly of the two structural elements for interconnec¬ tion thereof. Consequently, during this assembly operation, the tightening member is already placed in position inside the second structural element together with the tightening screw. This could be achieved without any risk that the components incorporated in the tightening device fall out during the assembly operation.

Preferably, the lateral recess in the second structural element presents laterally enlarged areas forming pivotal abutment means to allow the pivotal movement of the tighten¬ ing member. The latter is formed with side walls which straddle the gripping member and which are formed with pro¬ jections extending into the laterally enlarged areas of the lateral recess. The abutment cooperating with the gripp¬ ing member is formed by a web bridging the space between the lateral walls of the tightening member. Owing to this construction improved mutual guidence of the various compo¬ nents incorporated in the fastening device is achieved as well as improved guidence of the various components relative ly to the associated structural element.

Preferably, the gripping member is formed with an oblique edge adjacent its abutment designed for cooperation with the tightening member, said oblique edge designed to guide the tightening member relatively to the gripping member when the first structural element with the gripping member attached thereto is to be interconnected with the second structural element and the tightening member posi¬ tioned in the interior thereof. This arrangement efficientl prevents relative misalignment of the various components of the structural elements when the latter are assembled, an operation which thus is facilitated to a considerable degree.

One embodiment of the invention will be described in closer detail in the following with reference to the accompa ing drawings, wherein:

Fig. 1 illustrates the interconnected parts of two structural elements with parts cut away for illustration of the functior. of a fastening device incorporated in the elements;

Fig. 2 illustrates the first step of the sequence of assembly steps; Fig. 3 illustrates the second step of the sequence of assembly steps;

Fig. 4 illustrates the third step of the sequence of assembly steps;

Fig. 5 illustrates the fourth step of the sequence of assembly steps at the end of which the components assume the position illustrated in Fig. 1;

Fig. 6 is a perspective view of a first component in¬ corporated in the fastening device; and

Fig. 7 illustrates, likewise in a perspective view, a second component incorporated in the same fastening device For the purpose of clarity, all drawings figures 2 to 5 are partly cut perspective views.

In the drawings are shown two structural elements which are interconnected by means of the device in accordance with the invention. One of said elements is generally indi¬ cated by reference numeral 1 and the other one is generally indicated by reference numeral 2. Reference numeral 3 design the fastening device 3 which constitutes the interconnecting member proper. In accordance with the embodiment illustrated in the drawings, structural element 1 is in the form of a tube having rows of spaced-apart slots 4 along its length. The number of rows of slots may vary from one row to several according to need. In accordance with the embodiment illu¬ strated in the drawings, the structural element 1 is in the form of a vertical rod but obviously the inventive idea is applicable also to an element which is directed in another way. Also, the element 1 could have another cross-

sectional configuration than the circular one illustrated in the drawings. For instance, it could have a quadrangular configuration, such as a square or rectangular configuration In accordance with the embodiment shown, the structural element 2 is in the shape of a tube projecting from the structural element 1 at an angle α which need not be 90° as in the example illustrated in the drawings in order to make the inventive idea applicable. The fastening device 3 consists of two main parts, i.e. a gripping member 5 and a tightening member 6. The gripping member 5 is intended for insertion in either one of the slots 4 while gripping the edges thereof whereas the tightening member 6 is intende to exert a strong pulling force on the gripping member 5 in the direction inwards, into the structural element 2 while urging end edge 2A of the latter into abutment agains the external face of the structural element 1.

In accordance with the embodiment illustrated in the drawings, the gripping member 5 is in the shape of a disc having two wider hook portions 7 and 8 which are joined together by a narrower throat portion 9. At its lower edge, the throat portion 9 is defined by a downwardly open recess 10 the width a. of which equals or exceeds the thickness of the tube 1 in the slot 4. At its top, the neck portion is delimited by an upwardly open recess 11 the bottom of which is stepped in the form of ledges 12 and 13. The verti cal distance b between the ledge 12 and the inner delimitin edge 14 of the recess 10 equals or is smaller than the height of the associated slot 4. The vertical position of the ledge 13 is, however, chosen to ensure that the grippin member may be pivoted into position in the slot, as illustr in Fig. 2, when this ledge rests on the upper limiting edge face of the slot 4 and then be allowed to fall into the position illustrated in Fig. 3. In this position, the reces 10 engages the lower limiting edge face of the slot 4 and the ledge 12 slides inside the slot until the ertical edge face 15 of the hook portion 7 abuts against the? inner face of the tube. The hook portion 8 is delimited from the reces

11 by means of an abutment edge 16 which merges into an oblique wedge-shaped edge 18 via a projecting nose 17.

In accordance with the embodiment illustrated, the tightening member 6 is punched from a flat starting sheet 5 metal blank which is bent to the shape illustrated in Fig. 4. The tightening member 6 consist of two laterally spaced plates which in principle have the shape of a knee lever. The upwardly directed arms 19 of the knee lever are inter¬ connected by means of a bridge 20 extending between the

10 two laterally spaced arm plates. The other arms of the knee lever are indicated by numeral reference 21 in the drawing. At their lower ends, the laterally spaced plates are formed with one projection 22 each. Reference numeral 23 designates a tongue positioned adjacent the free end of one of the

•15 plates of the knee lever arm 21, which tongue is bent to the position illustrated in Fig. 7, wherein the free end thereof lies over and thus is supported by the opposite plate of the corresponding knee lever arm. In this manner, the tongue 23 bridges the space between the two laterally

20 spaced plates of the knee lever arm 21 in the form of a support. The height of the bridge 20 exceeds the distance between the ledge 13 on the hook portion 8 and the nose 17. The spacing between the plates forming the arms 19, 21 exceeds the thickness of the gripping member 5, allowing

25 the latter to be accommodated between the arm plates. The structural element 2 which is shown as a tubular element in the drawings, is formed in one of its faces, in accordanc with the embodiment shown the lower face, with a slit 24 the mouth of which is turned towards the end of the element

30 and which has a width exceeding the thickness of the gripp¬ ing member 5. In addition, the slit 24 is formed with two laterally enlarged opposite recesses 25 which are spaced from the end edge 2A of the tube and the extension of which in the longitudinal direction of the slit exceeds the width

35 d of the projections 22 at the bases of the latter. Numeral reference 26 designates an aperture disposed internally of the slit 24, through which projects a tightening screw

27 which is screwed into a threaded hole 28 formed in the support bridge 23 in the assembled condition of the device. Preferably, the head 29 of the tightening screw 27 has a conical configuration and is seated in a corresponding

' conical recess in the aperture 26 to ensure that the screw head will not project beyond the external face of the tube 2

The two structural elements are assembled in the follow manner.

Preferably, the gripping member 5 is inserted into the desired one of the slots 4 in the element 1, i.e. the slot at the vertical level at which it is desired that the structural element 2 should be positioned. The tightening member is then pivoted to the position illustrated in Fig. 3, as described in the aforegoing, i.e. the position, in which the bottom recess 10 in the tightening member engages the lower edge of the slot 4 and the ledge 12 in the grippin member assumes a position underneath the lower face of the upper delimiting edge of the slot. In this position, the abutment edge of the face 15 on the hook portion 7 abuts against the internal face of the tube. Consequently, the gripping member is prevented from being lifted from its position of cooperation with the upper as well as the lower edge face of the slot.

The tightening member 6 could be mounted in position inside the structural element 2 in advance. To mount the tightening member, one proceeds by tilting the member sligh and introducing the projections 22 thereon into the laterall enlarged recesses 25 of the slit 24. In the assembled posi¬ tion of the device these enlarged recesses form a pivotal connection allowing the pivotal movement of the tightening member 6. Af er introduction of the tightening member 6 into the hollow profile element 2 the tightening screw 27 is inserted into the support bridge 23 via the aperture 26.

With the gripping member 5 thus mounted in the structu element 1 and the tightening member 6 mounted inside the structural element 2, the end of the structural element 2

is placed adjacent or in abutment against the vertical element 1, as indicated by arrow A in Fig. 4, the gripping member 5 sliding inside the tube 2 along the slit 24 until its nose portion 17 has passed the abutment bridge 20, as indicated in Fig. 5. The tightening screw 27 is then tensio whereby a clockwise pivotal movement is imparted to the tightening member 6, the abutment bridge 20 of which abuts against the abutment edge 16 in the gripping member, forcin the latter into the interior of the structural element 2 with the result that the end edge of the structural element 2 will be pressed against the external face of the strucura element 1. By appropriate choice of the length of the arms 21 it is possible to obtain the desired magnitude of the clamping force interconnecting the two structural elements for a predetermined torque of the set screw 27.

In order to further improve the guided movements of the gripping member 5 the portion thereof that is positione inside the structural element 2 could be further prolonged downwards so as to project down into and be guided by the slit 24 in the tightened position of the device illustrated in Fig. 1.

The invention has been described and illustrated in the drawings by way of one embodiment thereof which is not, however, intended to limit the invention except as defined in the appended claims. The aforegoing description of the invention refers to its application to coupling together two tubes of circular cross-sectional configuration but obviously other shapes are possible without departing from the scope of the invention. The tightening member has been described as having the configuration of a tiltable knee lever but other types of tightening members are possible, for instance members designed for re-direction of the force by means of wedge-shaped members or similar means.