GB2226613A - Releasably connecting framework members - Google Patents

Description

1 "DEVICE FOR CONNECTING THE MEMBERS OF FRAMEWORK STRUCTURES CAPABLE OF

BEING DISMANTLED" The invention concerns a device for connecting the members of framework structures capable of being dismantled, claws being mounted at the free end of the upper chord and lower chord of each girder, the claws gripping in recesses of joint plates, and each two joint plates of a joint being connectible by means of a screw passed centrally through them.

A device of this kind is known for example from German Patent Specification No. 3222811.

In the known device, a claw is provided on both the upper chord and on the lower chord, in each case secured by means of welding, the claws being arranged to extend in opposite directions from one another. The claws are connected to the welded-on plates by means of narrow flanges extending vertically in the direction of assembly. These plates are mounted by welding on the corresponding chords of the lattice girders, the chords being formed as hollow sections. For assembling the joint plates, a joint member is provided, at a lower end of which a joint plate is fixedly welded on, while at its upper end, which is connectible to the upper chord, a releasably assembled joint plate is retained by means of a centrally disposed screw. In this known construction, the joint plates are provided, in their side regions which project above the joint member, with recesses open at the edges, in the form of slots and extending in the direction of the members to be connected, the claws or their flanges being engageable in the recesses.

The provision of slot-form recesses has proved disadvantageous in this form of embodiment, since they become widened out in the presence of tensile forces affecting the joint and in the extreme case they may even tear apart, so that a sufficient degree of safety is only to be achieved by substantial additional expense in construction, especially in the case of multi-storey construction.

1 Proceeding from this state of the art, it is an object of the invention to provide a device of the foregoing kind, which is able to withstand any loads applied in a problem-free manner by the use of connecting members which are very simple to manufacture, but without any consequent expectation of damage to the joint plates.

To meet this objective, the invention provides that the joint plates are formed as circular discs, one of which has a central through opening for a screw and another of which has a central threaded bore for the screw, the discs having groove-form recesses in their faces directed towards one another, concentric with the central opening or bore, and that the claws of the girders are formed by projections in the form of circular sectors mounted at each chord end, having on each side claws projecting in the direction of the groove-form recesses and curved to correspond to the configuration of the grooves, the claws being insertable between the joint plates and engageable in their groove-form recesses.

A divergence from the state of the art exists at each chord end. Thus both on the upper chord and also on the lower chord of a lattice girder, a claw is mounted directed upwardly in the assembly direction and another claw directed downwardly in the assembly direction. These claws are connected to welded-on plates by means of webs or flanges which are horizontal in the assembled position, the plates being welded on at the ends of the hollow sections which form the upper chord and the lower chord of the lattice girder. A further difference from the state of the art is that a pair of joint plates are provided for each pair of claws of a lower chord and of an upper chord, so that in the assembled position, the claws are covered on the upper side and on the lower side in each case by a joint plate, and further, the joint plates have groove-form recesses in their faces directed towards one another, concentric with the central opening, in which the claws may be engaged. The screw which in each case connects the joint plates of a joint and therefore also of the lower chord or of the upper chord has a length such that in preassembly of the joint plates relative to one another, the plates Z may be spaced at a distance from one another such that the corresponding chord with its claw may be inserted between the joint plates and engaged in the recess of the respective joint plate.

As soon as all upper chords and lower chords extending from the joint are correctly positioned at the joint, the screw may be tightened and optionally tensioned, so that a frictional and positive connection of the upper chords and the lower chords may be achieved by the joint plates. The manufacture of the connecting members, therefore of the welded-on components and the claws as well as the joint plates, is very easy to effect, since these connecting members may be made as straightforward turned components. For the manufacture of the connecting parts having the claws, these may be first of all turned from a circular disc, optionally shaped at its edges, and then divided into a suitable number of circular sectoral individual components, preferably into four identical sectoralform parts.

By means of the construction according to the invention, the formation of the open-edged slots which were hitherto necessary for engagement of the claws or their flanges is avoided, so that substantially higher loads may be taken up, and in addition, tearing apart of the slots, which was a hazard with the state of the art slots, is no longer possible.

It is also especially advantageous in the construction according to the invention that following completion of assembly, an optically unitary aesthetic impression is achieved at the joints, so that an aesthetically satisfying solution is also found. The construction according to the invention also facilitates the erection of multi-storey structures using this system, in which the framework formed by the lattice girders is suitable for mounting floor components, wall members and ceiling parts.

A preferred construction is also seen in forming and disposing the grooveform recesses of a pair of discs, as well as the discs themselves, to match each other.

More theoretically, it is also possible for the groove-form recesses to have a different spacing from the central axis of the respective joint plate. For reasons of uniform loading and transmission of forces, it is however preferred that these recesses should be arranged to match, the inevitable outcome being obviously that the claws also must in each case have the same spacings from the ends of the upper chord and of the lower chord.

Furthermore it is preferably provided that each circular sectoral-form projection covers at least approximately one quadrant of the associated disc.

A preferred further embodiment is seen in that the connecting part of each sectoral-form projection is curved to correspond to the exterior shape of the discs in the region abutting against the chord of the girder, as a result of which in particular the discs in their mounted disposition terminate flush with the one and the other side edge of the curvature and the components forming the chord also align flush with the curvature.

In this it can be further advantageous if the claws are not disposed at the free end of the projection carrying them, but that the projection extending from the part which is secured to the chord projects beyond the claws in the longitudinal direction of the projection, which extends horizontally to the assembly direction, so that the groove-form recesses for reception of the claws may bedisposed at a substantial spacing from the central opening of the disc-form joint plates.

It is further provided that the hooks have a free length corresponding approximately to the thickness of the projection carrying them.

Preferably it is further provided that the discs are approximately three times as thick as the projection.

In order to achieve a good fit, it is further provided that the grooves and the claws are shaped conically.

In order to avoid a double fit, it is preferably provided that the grooves are slightly deeper than corresponds to the free length of the claws.

Furthermore it is preferred that the heads of the screws are in each case arranged on the inner side of the girder with respect to the upper and lower chord of a girder, and the discs provided with a threaded bore are arranged on the outer side.

In a further embodiment it is proposed that the inwardly-disposed discs of a joint be connected to one another by means of a joint member or pillar.

In this manner it is possible to be able to also provide joint members or pillars at structurally determined positions.

Furthermore, it is possible for the outwardly disposed discs to be connected by a pillar or an upright.

In this manner it is possible for the lattice girders to be supported on their upper side by the floor located above them and to be supported on their lower side either on the floor located below them or the ground floor.

Embodiments of the invention are shown in the drawings and are now described in detail in the following text.

Figure 1 shows a joint in a chord of a lattice girder in side view, partially in section; Figure 2 shows the same joint seen from below; 1 Figures 3 to 8 show the individual connecting members of joint in individual views; Figure 9 shows the connection of lattice girders having joint members and struts, in side view, partially broken away; Figure 10 shows a joint in a view corresponding to that of Figure 1; Figures 11 and 12 are representations of the principles underlying framework assemblies according to the invention; Figure 13 shows a variant in the representation according to Figure 1.

In the drawings, the device for connecting the girders of framework structures capable of being dismantled is shown, in which at the free end of the upper chord 1 and of the lower chord 2, double claws 3 are mounted, which engage in corresponding recesses of joint plates 4 and 5. In each case, the two joint plates 4 and 5 of a joint are connectible by means of a screw 6 passing centrally through them. According to the invention, the jqint plates 4 and 5 are formed as circular discs, as can be seen in particular from'Figures 3 to 6. One of the discs, 4, has a central through opening 7 for a screw, while the other disc 5 has a similar central threaded bore 8. Concentric with the central opening 7 or 8, channel-shaped recesses 9 are provided in the faces of the discs 4 and 5 which are directed towards one another. The channels or grooves are formed by closed annularly-configured recesses. The members carrying the claws 3 are formed in circular segmental or sectoral manner by means of welded-on parts 10, as can be seen in particular from Figure 7. These members are for welding onto the girders.

At each end of an upper chord 1 or of a lower chord 2, a member of this kind is welded on. The claws 3 extend therefore during assembly vertically from a connecting web or flange 11 of the 2 1 1 welded-on part, this connecting web or flange extending in a horizontal direction in the assembled position. The sectoral projections formed by the flanges 11 are provided on each side with claws 3, projecting in the direction of the groove-form recesses 9 and curved to correspond to the shape of these grooves or channels. These claws are in each case insertable, in the assembly position, between the joint plates 4 and 5 and engageable in their groove-form or channel-shaped recesses 9. During pre-assembly, the screw 6 is only loosely screwed into the threaded hole 8 of the disc 5, so that the discs 4 and 5 have a spacing between their facing surfaces such that the double claw 3 may be inserted into the intermediate space thus defined and then introduced into the recess 9 which is lowermost in the assembled position. During assembly, the attachment of further lattice girders to an already finished erected lattice girder takes place in such a manner that the discs 4 and 5 are engaged against the corresponding end portion (double claw 3) of the erected lattice girder by means of the loosely screwed-in screw 6, so that the disc 4 or 5 which is uppermost in the assembly direction is located with its recess over the claw 3 which extends upwards with respect to the assembly direction. The further lattice girders may then be introduced into the space defined between the discs 4 and 5 of a joint, following which the lower claws 3 of these lattice girders are located in the recess 9 which is then lowermost. After the insertion of all connecting members at this joint, the screws 6 are tightened up, following which the connection at this joint is complete. The screws are preferably formed as screws having internal polygonal openings in their heads by which they may be tightened using a suitable key or spanner (high tensile screws).

Because of the annular configuration of the recesses 9 and the corresponding circular sectoral shape of the claws 3, it is possible to assemble lattice girders at different angles to one another at a joint. In a particular embodiment, the dimensions are so chosen that in the case of four lattice girders coming together at a single joint, only a rightangle disposition of the lattice girders with respect to one another is possible. In so far however as only i three such lattice girders are to be connected together at a joint, a relative angular disposition deviating from the symmetrical 120 0 disposition is possible.

The groove-form recesses 9 of a pair of discs 4, 5 are also formed and designed to be the same as one another, as are the discs themselves. Furthermore, each circular sectoral projection formed by the flange or web portion 11 extends over at least a quarter circle of the associated disc 4 or 5. The connecting part 10 of each sectoral projection is curved to correspond to the exterior shape of the disc 4 or 5 in the region abutting against the chord 1 or 2 of the girder, so that the discs 4, 5 are flush with the one or the other edge periphery of the curvature in their mounted positions, as is shown for example in Figure 1, and the components forming the chords 1 and 2 are also aligned flush with the curvature. In the embodiment, the claws 3 have a free length corresponding approximately to the thickness of the projection 11 which carries them. The discs 4, 5 are approximately three times as thick as the projection 11. As can be seen for example from Figures 3, 6 and 8, the grooves 9 and the claws 3 have conical shapes which match one another, the grooves 9 having a depth slightly greater than the free length of the claws 3, so that in the desired assembled disposition, as is shown for example in Figure 1, the end surfaces of the claws 3 in the vertical direction have a spacing from the base of the recess 9. In this way, a double fit is avoided.

For cantilevered or self-supportingly located lattice girders, the assembly is preferably so arranged that the heads of the screws 6, which project on the external side of the thread-free disc 4, are in each case disposed on the inner side of the girder with respect to the upper chord 1 or the lower chord 2 of a girder, while the disc 5 provided with the threaded hole is disposed on the outer side. This is shown for example in Figure 10. In this way, an aesthetically especially successful impression is achieved, since the heads of the screws as a disturbing element are practically invisible from the exterior. In addition, the screw heads do not then form z 1 projections interfering with the installation of ceiling or floor elements. In the embodiment according to Figure 9, the inwardly-disposed discs 5 of a joint are connected to one another by means of a joint member or column 12. The joint member is formed as a hollow section. For securing the joint member, a connecting member 13 is in each case welded onto the disc 5. These connecting members are aligned coaxially with one another. The joint member 12 is mounted by means of corresponding securing screws 14, preferably screws having internal polygonal openings in their heads. Member 12 has centrally apertured end plates 15. In order for the screws 14 to be accessible for a suitable tool, the joint member has openings 16, into which the flexible shaft of a screwdriver may be introduced in known manner, so that the screws 14 may be tightened by motor means. Similarly, in Figure 9 of the drawings, the outwardly located discs 4 are shown to be connected by a pillar 18 or an upright 17. For adjustment and to ensure correct positioning, a sleeve-form socket 19 is welded onto the disc 4 centrally, over which a corresponding end plate 20 of the pillar or of the upright engages. In this manner, a sufficient level of accuracy in positioning is achieved. Obviously it is also possible to connect up the pillar or the upright by means of a welded connection or a screw connection. In order to achieve sufficient clearance for movement relative to the inclined struts 21 of the lattice extending from the lower chord 2 or the upper chord 1 and to achieve an at least approximately concentric entry of the inclined struts 21 into the joint, the inclined struts 21 are received in the connection region of the discs 5 and 4, the recess 22, which corresponds to the required spacing of the discs 4 and 5 from one another, having a height such that the introduction of the claws 3 between the pre-assembled discs 4 and 5 is possible.

In Figures 11 and 12 of the drawings, two possible variants of embodiments of girder structures are shown. In the variant of Figure 11, an upright or a pillar 17 or 18, as well as a joint member or column 12, is provided at each joint of the lattice girders. In this manner, for example, the construction of multi-storey structures is possible. In the variant according to Figure 12, the arangement is so devised that only uprights 17 are provided, with as a result the fact that the inclined struts of the lattice girder converge in each case at the upper end point of the upright 17. In this arrangement additional joint members 12 may be avoided. This means on the one hand a substantial cost saving, and on the other hand, a slopingly extending configuration of the framework is in this manner possible on the outer skin of the structure, as is to be seen at the left-hand side of Figure 12.

The embodiments in no way represent a limitation.

In deviation from the embodiments shown, the head of the screw 6 may obviously also be arranged to be sunk in an appropriately stepped receiving bore in the disc 4, a screw having an internal polygonal head opening then preferably being used.

All components of the device preferably consist of steel.

For aesthetic reasons, it may also be advantageous for the threaded bore 8 to be formed as a blind hole, so that the outwardly directed surface of the disc 5 in the assembled position may be formed to be flat and smooth and free from openings. It is also possible to connect girders rigidly to one another using the connecting components formed according to the invention, in which for example at the end of two girders to be connected to one another, connecting parts 10 forming a circular sector of 1800 are in each case welded-on. In the assembly of girders of this kind with ' corresponding discs 4, 5, a continuous connection is achieved which is rigid in the axial and the radial directions of the connecting member. It is also possible to fit girders with welded-on components 10 having web or flange portions 11 extending over 900 of a circular sector. The free space between the two 900 sectors may then be filled by means of appropriate filler portions (also 900 sectors).

1 1 In particular in the case of tensile loading occuring, it is advantageous for the transition between the curved welded-on part 10 and the sectoral flange part 11 to have a radius of for example 10 mm, the discs being bevelled to extend conically corresponding to said radius. The conical bevelling of the discs 4, 5 in their radially outwardly disposed regions should therefore extend at a maximum over approximately one-third of the height of the disc 4 or 5 from its inner abutment edge against the flange part 11. By bevelling the discs 4 and 5, a further aid to assembly is also provided. Furthermore, it is possible for the fitting of the welded- on part 10, claws 3 and recesses 9 of the discs 4 and 5 to be effected so that in the event of tensile forces occurring, the flanks of the claws 3 that are loaded in the tension direction abut in a load-carrying manner on the sides of the recesses 9, while in the case of compressive forces occuring, the surfaces of the welded-on parts 10 abut against the radially outwardly-disposed surfaces of the discs 4, 5. The side edges of the claws 3 which are forwardly located with respect to the direction of compressive loading may have therefore a certain spacing or clearance from the corresponding associated flanks of the recesses 9 of the discs 4, 5.

This variant is shown in Figure 13 of the drawings.

The invention is not limited to the embodiments, but may be varied in a multiplicity of manners within the scope of the disclosure.

All new features disclosed either individually or in combination in the description and/or the drawings are regarded as forming part of the invention.

a

Claims (14)

1. A device for connecting the members of framework structures capable of being dismantled, claws being mounted at the free end of the upper chord and of the lower chord of each girder, the claws engaging in recesses of joint plates, and each two joint plates of a joint being connectible by means of a screw passing centrally through them, wherein the joint plates are formed as circular discs, one of which has a central through opening for a screw and another of which has a central threaded bore for the screw, the discs having groove-form recesses in the faces of the discs directed towards one another, concentric with the central opening or bore, and the claws of the girders are formed by projections, of circular sectoral form, mounted at each chord end, the projections having on each side claws curved to correspond to the configuration of the grooves and projecting in the direction of the groove-form recesses, the claws being insertable between the joint plates and being engageable in the grooveform recesses of the plates.

2. A device according to Claim 1, wherein the groove-form recesses of a pair of discs as well as the discs themselves are formed and disposed to match one another.

3. A device according to Claim 1 or Claim 2, wherein each circular sectoral projection covers at least approximately a quarter circle of the associated disc.

4. A device according to any of Claims 1 to 3, wherein a connecting part of each sectoral-form projection is curved to correspond to the exterior shape of the discs in a region abutting against the chord of the girder, the discs terminating flush w ' ith the one or the other side edge of the curved portion of the connecting part in the mounted position and the components forming the chords being likewise aligned flush with said curved portion.

5. A device according to any of Claims 1 to 4, wherein the t claws have a free length corresponding approximately to the thickness of the projection carrying them. 0

6. A device according to any of Claims 1 to 5, wherein the discs are approximately three times the thickness of the projection.

7. A device according to any of Claims 1 to 6, wherein the grooves and the claws are conically shaped.

8. A device according to any of Claims 1 to 7, wherein the grooves are slightly deeper than corresponds to the free length of the claws.

9. A device according to any of Claims 1 to 8, wherein the heads of the screws are in each case disposed on the inner side of the girder with respect to the upper and lower chord of a girder and the disc provided with a threaded bore is disposed on the outer side.

10. A device according to any of Claims 1 to 9, wherein inwardly disposed discs of a joint are connected to one another by a joint member.

11. A device according to any of Claims 1 to 10, wherein outwardly disposed discs of a joint are connected by means of a pillar or an upright.

12. A connecting device substantially as described herein with reference to and as shown in Figures 1 to 8, Figure 9, Figure 10 or Figure 13 of the accompanying drawings.

13. A framework assembly comprising a connecting device according to any of Claims 1 to 12.

14. A framework assembly substantially as described herein with reference to Figure 11 or Figure 12 of the accompanying drawings.

Pubhshed 1990 at The Patent Office, State House, 6671 High Hol oorn. London WC 1R 4TP Further copies maybe obtained from The Patent office