AU641034B2 - Connection means - Google Patents

Description

410534

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION For a Standard Patent

ORIGINAL

e.

0 0 0 TO BE COMPLETED BY APPLICANT Name of Applicant: Actual Inventor(s): Address for Service: NOVAPLAS PTY LTD PHILLIP GRAHAM CALOW WRAY ASSOCIATES, Primary Industry House, 239 Terrace, Perth, Western Australia, 6000.

Adelaide Attorney code: WR Invention Title: "Connection Means" Details of Associated Provisional Application: No: PK 468 The following statement is a full description of this invention, including the best method of performing it known to us:- 2 THIS INVENTION relates to space frames and in particular to screw connection means for connecting a frame member to a nodal connecting member.

In one form the invention resides in a screw connection means for space frame structures for connecting a frame member to a nodal connecting member, the screw connection means comprising: a rotatable member disposed between the frame member and the nodal connecting member, the rotatable member being rotatable relative to the frame member and the nodal connecting member, said rotatable member comprising a turning means to enable rotation to be imparted thereto; a threaded bolt comprising a portion of non-circular crosssection disposed between a threaded end and a head end; and a locking element adapted to engage with said portion of o non-circular cross-section of the bolt such that relative ^rotation therebetween is substantially prevented, said locking element being further adapted to be engagable in a recess in the rotatable member such that relative rotation therebetween is substantially prevented; wherein rotation of the bolt is effected by rotation of the rotatable portion thereby threadingly engaging the bolt to the nodal connecting member, and wherein the portion of the threaded bolt which is of non-circular cross-section comprises a 4 neck portion made up of two parallel planar surfaces recessed into laterally opposite sides of the bolt.

f The rotatable member preferably comprises a frusto-conical housing, having an axially extending circular hole adapted to allow the threaded end of the bolt to pass through, and having its smaller end thereof adjacent the nodal connecting member.

In a preferred form of the invention, the bolt is axially displaceable to a limited extent relative to the rotatable member, while the locking element may also be axially 3 displaceable to a limited extent within the recess in the rotatable member. In addition or alternatively, the locking element may be axially displaceable to a limited extent with respect to the bolt.

Further, the locking element preferably comprises a "U" shaped clip, the two legs of which are parallel, the distance between the inner sides of the two legs corresponding to the distance between the two parallel planar surfaces recessed into laterally opposite sides of said bolt.

Preferably, the turning means comprises one or more indentations on the outer surface of the rotatable member adapted to be engagable with a spanner for imparting a 3. turning torque thereto.

;o '"Furthermore, the shaped clip may be of a rectangular shape and the recess in said rotatable member may be of a corresponding rectangular shape.

The invention will be better understood by reference to the following description of one specific embodiment thereof as shown in the accompanying drawings in which:- Figure 1 is a schematic view of a space frame incorporating frame member interconnected by screw connection means, according to the embodiment; Figure 2 is an exploded view of a screw connection means according to the embodiment; and Figure 3 is an assembled and sectioned view of the screw connection means as shown in Figure 2.

The embodiment shown in the drawings is directed to a screw connection means which is employed in a space frame structure which is shown schematically in Figure 1 and 3a which comprises a defining cords, 13 defining webs.

and intersect at plurality of horizontal frame members 11 and a plurality of inclined frame members .he frame members 11. and 13 are tubular nodal connecting members which are in the .i i 4 4 .4 4 4 4*44 4.

*4 fl~ 4 form of spherical joints 15. A screw connection means 17 according to the embodiment provides a means for connecting at least one end of a frame member to a corresponding spherical joint.

Each screw connection means 17 comprises a rotatable member in the form of a frusto-conical housing 19 having a recess in the form of a rectangular hole 21 and an axially extending circular hole 23 therethrough. Turning means in the form of indentations 25 and a spanner (not shown) are also provided. At the larger end of the frusto-conical housing, that is the end having the recess in it, there is provided a raised section 26 which has a circular periphery i. and which is adapted to fit into the end of the tubular frame member 11 such that the annular surface 51 defined 15 between the raised portion 26 and the outer diameter of the frusto-conical housing, is able to come into close contact with the annular surface 53 of the tubular frame member 11.

*4 Advantageously the maximum outer diameter of the frusto-conical housing is the same as the outer diameter of the tubular frame member, thereby providing an aesthetically pleasing transition from the tubular frame a member to the corresponding spherical joint.

Each screw connector means 17 further comprises a threaded bolt 27 which is retained in the frame member 11 by a retaining plate 31 which is welded into position. The threaded bolt is free to rotate and/or move axially within the retaining plate. However, to prevent the bolt from S* dropping into the frame member during assembly the bolt may be provided with an elastic O-ring (not shown) which has an outer diameter larger than the corresponding diameter of the hole in the retaining plate.

The bolt is provided with a portion of non-circular cross-section in the form of a neck portion made up of two parallel planar surfaces 33 recessed into laterally opposite sides of the bolt. The positioning of the neck 5 portion with respect to the axial extent of the bolt will be determined by a requirement for the bolt, when the screw connection means is assembled, to allow axial displacement, to a limited extent relative to said frame member.

The bolt is to provide a convenient gripping means whereby the bolt may be acted upon so as to cause rotation of same.

An advantageous aspect of having the non-circular crosssection portion in the form of a neck portion is that to form the neck material can be removed from the bolt rather than, say, building up the material onto the bolt. In this way a conventional bolt and conventional machining processes may be utilised. Furthermore, by careful consideration of the configuration of the portion of non- 6circular cross-section, stress raising factors caused in 15 the bolt may be minimised. In the particular embodiment the use of recessed faces has the advantage in that it creates lower stress raising factors than, say, a lateral a. hole, which to achieve the desired result of a gripping means would have to have some type of pin engaging with it.

Each screw connection means further comprises a locking element in the form of a shaped clip 35 having a base e. portion 37 and two leg portions 39 depending therefrom.

The clip has a constant cross-section through its main plane. The outer envelope of the clip, taken in the main plane, forms a generally rectangular shape the dimensions of which conform to the rectangular recess 21 in the ,housing 19.

The leg portions 39 have inner faces 41 each of which faces the other and is parallel thereto, the distance therebetween corresponding to the distance across the parallel planar surfaces 33 of the bolt.

To assemble a frame member, including the screw connection means, into a space frame, various methods can be used.

The particular case described below is but one example.

6 In this example a frame member is to be inserted between two established spherical joints 15. The distance between the two spherical joints is fixed and they are not movable, at least to any great extent, relative to each other.

The frame member has one end to which a bolt has been fixed into position. This bolt cannot move relative to the frame member and in order for it to engage a spherical joint the frame member must be bodily rotated.

In order that the frame member may be aligned into position between the two spherical joints the frusto-conical housing 19 is not assembled onto the frame member and the bolt 27 is retracted into the frame member such that only a relatively small portion of the threaded end is exposed.

*e This arrangement will allow the overall length of the frame S 15 member to fit between the spherical joints. The frame member is then bodily rotated so that the fixed bolt engages with its respective spherical joint.

Subsequently, the bolt 27 is extracted from the frame member. The frusto-conical housing is then guided over the 20 bolt and a sufficient gap is left between the housing and the frame member so as to enable the U-shaped clip 35 to Sengage with the neck portion of the bolt. The frusto-conical housing is then manipulated so that the U-shaped clip is received within the recess 21.

25 In order that the bolt 27 may be able to move axially relative to the frame member, allowance has been made in the depth of the rectangular recess 21 so that it is greater than the thickness of the U-shaped clip The frusto-conical housing is then rotated by a spanner which engages the indentations 25, until the frame mimber is pulled up tight against the frusto-conical housing which is in turn pulled up tight against the spherical joint.

A particularly advantageous aspect of using a frusto-conical housing orientated with its smaller end towards the spherical joints is that it allows more frame members to be attached to the same spherical joint, or conversely it allows for the use of a smaller spherical joint for a particular sized frame member.

A further r cinement may be made to the above embodiment by adapting a seal between the frusto-conical housing and the frame member and the frusto-ccnical housing and the spherical joint. With respect to the first seal arrangement a convenient form would be to place a seal between face 51 of the frusto-conical housing and face 53 of the frame member. A sealing arrangement as described above would ensure that the working parts of the screw connection means and the internal areas of the frame member o* are protected from contamination and corrosion. A certain 15 aesthetic appeal is also created by the fact that the working parts of the screw connection means are either hidden or take on a general pleasant form, such as the frusto-conical housing described above.

It should be appreciated that the scope of the invention is not limited to the scope of the embodiment described.

In particular an arrangement wherein the bolt 21 is retained within the nodal joint member and threadingly engages the frame member envisaged.

9

Claims (8)

1. A screw connection means for space frame structures for connecting a frame member to a nodal connecting member, said screw connection means comprising: a rotatable member disposed between the frame member and the nodal connecting member, the rotatable member being rotatable relative to the frame member and the nodal connecting member, said rotatable member comprising a turning means to enable rotation to be imparted thereto; a threaded bolt comprising a portion of non-circular cross-section disposed between a threaded end and a head end; and a locking element adapted to engage with said portion of non-circular cross-section of the bolt such that relative rotation therebetween is substantially prevented, said locking element being further adapted to be engagable in a recess in the rotatable member such that relative rotation therebetween is substantially prevented; wherein rotation of the bolt is effected by rotation of the rotatable portion thereby threadingly engaging the bolt to the nodal connecting member, and wherein said portion of non-circular cross-section comprises a neck portion made up of two parallel planar surfaces recessed into laterally opposite sides of said bolt.

2. A screw connection means according to claim 1, wherein said bolt is axially displaceable to a limited extent relative to said rotatable member.

3. A screw connection means according to claim 1 or claim 2, wherein said locking element is axially displaceable to a limited extent within said recess in Paid rotatable member.

4. A screw connection means according to any one of claims 1 to 3 wherein said locking element is axially displaceable to a limited extent with respect to said bolt. 9 A screw connection means according to any one of claims 1 to 4, wherein said locking element comprises a "U" shaped clip, the two legs of which are parallel, the distance between the inner sides of the two legs corresponding to the distance between the two parallel planar surfaces recessed into laterally opposite sides of said bolt.

6. A screw connection means according to claim 5, wherein said shaped slip i. of a rectangular shape and said recess in said rotatable member is a corresponding rectangular shape.

7. A screw connection means according to any one of claims 1 to 6, wherein said rotatable member comprises a frusto-conical housing, having an axially extending circular hole adapted to allow the threaded end of the bolt to pass through, and having its smaller end thereof adjacent said nodal connecting member.

8. A screw connection means according to any one of claims 1 to 7, wherein said turning means comprises one or more indentations on tha outer surface of said rotatable member adapted to be engagable with a spanker for S" imparting a turning torque thereto,

9. A screw connection means according to claim 1 substantially as herein described in relation to the accompanying drawings. DATED this SECOND day of JULY 1993 NOVAPLAS PTY LTD Applicant. WRAY ASSOCIATES, Perth, Western Australia, Patent Attorneys for the Applicant. ABSTRACT A screw connection means for space frame structures for connecting a frame member to a nodal connecting member. The screw connection means comprises a rotatable member disposed between the frame member and the nodal connecting member, the rotatable member being rotatable relative to the frame member and the nodal connecting member. The rotatable member also comprises a turning means to enable rotation to be imparted thereto. The screw connection means also includes a threaded bolt comprising a portion of non-circular cross-section disposed between a threadel end and a head end, and further includes a locking element adapted to engage with said portion of non-circular cross- section of the bolt such that relative rotation 4 S therebet-een is substantially prevented. The locking G. element is further adapted to be engagable in a recess in the rotatable member such that relative rotation therebetween is substantially prevented. Rotation of the bolt is effectid by rotation of the rotatable portion thereby threadingly engaging the bolt to the nodal connecting member. 6 0 *a a a am c 0 40 0 S