WO1987001150A1

WO1987001150A1 - Adjustable space frames

Info

Publication number: WO1987001150A1
Application number: PCT/AU1986/000239
Authority: WO
Inventors: Garry Randall Hart
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-08-16
Filing date: 1986-08-18
Publication date: 1987-02-26
Anticipated expiration: 1988-02-16
Also published as: AU6226886A; GB2199865A; JPS63500877A; EP0267914A1; AU593011B2; GB8803500D0; EP0267914A4; GB2199865B

Abstract

An adjustable space frame (10) has upper and lower grids (11, 12) formed of longitudinal and lateral chords (13, 14) connected to vertical posts (15) at nodal connection points. Tension braces (16) interconnect the chords (13) in the respective grids (11, 12). By selective adjustment of the tension in the tension braces (16), the degree of rigidity in the space frame (10) can be varied and the space frame (10) may be selectively curved or cambered in either the longitudinal and/or lateral directions. When rigid braces (17) are used in the lateral direction, the curvature will be in the longitudinal direction. The posts (15) may be inclined to provide lateral restrain for the space frame (10) and the grids (11, 12) may be relatively offset.

Description

TITLE: "ADJUSTABLE SPACE FRAMES"

BACKGROUND OF THE INVENTION

(1) Prior Art

THIS INVENTION relates to adjustable space frames. The invention is also directed to improved methods for connecting and bracing the space frame components .

(2) Prior Art

Spaces frames are particularly suited to span- ning large areas where minimal obstruction by support¬ ing columns is required. Existing space frames gen¬ erally consist of interconnected members which form non-adjustable triangulated structures which have a number of practical limitations. The frames often require expensive mode connectors and the components manufactured to close tolerances. The space frames are generally rigid and unyielding and are difficult to assemble. Curved structures generally require special members and increase construction time. Finally, they are difficult to design as the use of a large number of components connected at modes make them difficult to computer model as complex computer design analysis techniques must be employed. SUMMARY OF THE PRESENT INVENTION It is an object of the present invention to provide adjustable space frames which are easy to assemble and which do not require close tolerances in the components .

It is a preferred object to provide adjustable space frames which avoid the need for complex mode connectors and yet allows for a wide range of geo¬ metries, including curved frames.

It is a further preferred object of the present invention to provide adjustable space frames which can be pre-ca bered and which can be very ductile to very rigid dependent on the proposed appli¬ cation.

It is a still further preferred object to provide adjustable space frames which can be easily analysed and assembled in the manner of two dimen¬ sioned trusses and which can be easily tarried to suit different stresses on the components throughout the frames .

Other preferred objects of the present invention will become apparent from the following description.

In one aspect the present invention resides in an adjustable space frame including: an upper grid of chords intersecting at a plurality of modes and a lower grid of chords inter¬ secting at a plurality of modes wherein: at least one of- the modes in the upper grid is connected to at least one of the modes in the ^'lower grid by a tension and/or compression brace or strut being adjustable to apply and curvature to the space frame and/or to vary the rigidity of the space frame.

Preferably the modes of the upper grid are connected to corresponding modes in the lower grid by posts to which the chords are connected, and a pair of diagonal tension braces interconnect the modes on an adjacent pair of posts in the frame.

Alternatively, in a rectangular frame, which is plan view, appears to consist a series of inter¬ connected "boxes", the tension braces may extend dia- gonally across the boxes between the posts at opposite corners of the boxes .

The tension braces may be arranged longitudi¬ nally and/or laterally relative to the frame to enable cambering of the frame in one or two directions. Non-adjustable braces may be provided in the direction which does not require cambering or curvature. The frames may be triangular, square, rectangular, hexa¬ gonal or any other suitable regular polygon in plan view and the chords of the lower grid may underlie, or be offset relative to the chords of the upper grid. In a second aspect the present invention resides in a method for connecting the chords to a mode of a space frame including: a post at the mode; at least one stub extending from the post to engage a respective chord in the space frames; and means to connect the chord to the stub. In a third aspect the present invention resides in a method for connecting the chords to a mode of a space frame including: a post at the mode; at least one hole or slot in the post to receive a respective chord in the space frame; and means to connect the chord to the hole or slot in the post.

The tension bracing may include a pair of U- or D-shaped brackets, or L-shaped straps, connectable to the chords and/or posts by bolts or other fasten¬ ers, interconnected by rods or flexible cables; tensioned rods received in holes in the chords are tensioned by nuts on threaded ends of the rods; or a pair of rods connected by a turnbuckle.

BRIEF DESCRIPTION OF THE DRAWINGS To enable the invention to be fully understood a number of preferred embodiments will now be des¬ cribed with reference to the accompanying drawings, in which:

FIG. 1 is a isometric view of a space frame adjustable in one direction; FIGS. 2 to 4 are isometric views of triangu- lar, hexagonal and hexagonal space frames respect¬ ively;

FIG. 5 is an isometric view of a space frame where the lateral chords in the grid are offset; FIGS. 6 to 16 show alternative methods of connecting the chords to the posts;

FIGS. 17 to 21 show alternative types of tension braces ;

FIG. 22 is a rigid panel which can be used in substitution for the rigid, non-adjustable brace;

FIG. 23 shows a method for relieving stress in a strut or brace;

FIG. 24 is a side view of a second type of space frame having blocks at the modes in substitution for posts ;

FIG. 25 is an underside isometric view of one of the blocks;

FIG. 26 is a side view of a third type of space frame using inclined posts and adjustable chords; and

FIG. 27 is an isometric view of the space frame of FIG. 26.

DETAILED DESCRIPTION OF THE PREFERREDEMBODIMENTS Referring to FIG. 1, the space frame 10 has respective upper and lower grids 11, 12 with longitu¬ dinal and lateral chords 13, 14 connected to vertical posts 15 at modal connection points defining regular rectangular boxes. Tension braces 16, indicated by dashed lines, interconnect the longitudinal chords 13 of one grid with the aligned longitudinal chords 13 of the other grid, while rigid braces 13 interconnect the lateral chords 14. By selective adjustment of the tension braces 16, the frame 10 may be cambered or curved along the longitudinal "trusses".

As an alternative, the tension braces may be provided diagonally across the "boxes" as indicated by the solid lines 16a to produce a highly rigid frame. (If the tension braces 16 have a low tension, the frame 10 will be very ductile in the longitudinal direction while being very rigid in the lateral direction due to the rigid braces 17.) By increasing the tension in the tension braces 16, the frame 10 will become more rigid in the longitudinal direction.

FIGS. 2 and 3 show triangular and hexagonal space frames 20, 30 respectively, where the tension braces 21, 31 lie within vertical planes inter- connecting the posts 22, 32, while FIG. 4 shows a hexagonal space frame 40 where the tension braces 41 extend diagonal across the frame to connect diagonally opposed posts 42. In all these frames, the chords 23, 33, 43 in the upper and lower grids are vertically aligned.

FIG. 5 shows a space frame 50 where the posts 51 are inclined so that the lateral chords 52 of the upper grid are offset relative to the lateral chords 53 of the lower grid, the longitudinal chords 54 being aligned and the tension braces 55 lie along the longi¬ tudinal and lateral axes of the frame. This arrange¬ ment provides lateral restraint. in the longitudinal directions of the frame.

The methods of connecting the chords to the posts will now be described.

Referring to FIG 6, tubular stubs 60 are welded to, and extend laterally from the vertical post 61, each stub 60 being arranged to be received in a respective chord 62, with aligned holes 63, 64 being provided to receive suitable fasteners (not shown) to transfer the load from the chord to the stub in shear.

In FIG. 7, a block 70 is provided with the stubs 71.

FIG. 8 shows a post 80 where the stubs 81 are formed by a pair of tubes 82 extending through the post, while FIG. 9 shows a post 90 where a chord 91 extends through the post and receives and supports a chord 92 of reduced diameter. This arrangement is particularly suitable where different forces occur in the space frame. . Alternatively, the posts 100 has a pair of sleeves 101 to receive chords 102 in one direction and a pair of stubs 103 to be inserted in the chords 102 in the other direction.

The stubs 110 (or sleeves) may be inclined to the posts 111 to receive the chords^" 112 at any suit- able angle.

The post 120 in FIG. 2 has aligned pairs of

"slots 121, 122 to receive sleeve connectors 123 (or continuous chords) in an overlapping arrangment .

Alternatively, slots 130 may be provided adjacent the ends of the chords 131 to engage the side t walls of the posts 132. In FIG. 14, the post 140 has slots 141 which receive the chords 142, which are locked by the engagement of the side walls of the slots 141 in slots 143 formed in the chords. FIG. 15 shows the chords 150 received in holes in the posts 151 and locked by wedges 152 engaged in slots 153 in the chords.

In FIG. 16, the ends of the chords 160 abut the side walls of the post 161 and are secured thereto by threaded tension rods 162 which extend through the chords and are tensioned by nuts 163.

The embodiments described and illustrated are not exhaustive of the methods available to connect the chords to the posts in the space frames of FIGS. 1 to 5. Referring now to FIG. 17, a tension brace 170 has a U-shaped bracket 171 at each end, each bracket being connected to a respective stub 172 (or sleeve) and chord (not shown) adjacent the post 173 by a bolt fastener 173. The brackets of each brace 170 are connected by a tension rod 175 fitted with tensioning nuts 176. (As an alternative, short thread lengths of tension rod 175 can be provided at each end of a tension cable - not shown. ) In FIG. 18, the tension brace 180 has substan¬ tially L-shaped brackets 181 which receive the ends of the tension rod 182, while in FIG. 19, the ends of the tension rods 190, forming the tension braces, are bent to enable connection directly to the stubs 191 (or chords) on the post 192, the tensioning being effected by the nuts 193.

As shown in FIGS. 20 and 20a, the tension braces 200 may also be connected to the posts 201 or be overlapped for connection to the stubs and chords 202 on the opposite sides of the posts.

FIG. 21 shows a tension brace 210 which com¬ prises a pair of hollow tension tubes 211 internally threaded to receive a connecting rod 212 in the manner of a turnbuckle to provide the necessary tension. In FIG. 1, rigid braces 17 were provided in the lateral direction of the frame. These may be replaced by rigid infill panels 220 (see FIG. 22) which may engage stubs 221 on the posts 222.

FIG. 23 shows a modification of the modal connection of FIG. 16 where washers 230 of neoprene (or other suitable elastomeric material) are inter¬ posed between the ends of the chords 231 and the post 232 to accommodate differences in tolerances in the chords . In all the preceding embodiments, the posts interconnect the upper and lower grids in the space frames.

In the space frame 240 in FIG. 24, the chords 241 are of the type shown in FIGS. 16 or 23 and are connected to mode blocks 242 the blocks 242 in the grid being connected to compressure/tension brackets 243 formed in the manner of the chords 231 in FIG. 23, being provided with the washers 230. and with tension rods extending through the braces. As the longitud- inal and lateral chords of the upper grid are offset relative to the chords of the lower grid, a multi- way triangulation is generated in the frame 240.

The space frame 260 shown in FIGS. 26 and 27 has fixed length posts 261 which are interconnected to adjustable length chords 262 at the modes, the ends of the post being angled in two directions to allow for the inclination of the posts 261 and of the truss 270 indicated by shading in FIG. 27. The chords 212 may comprise a pair of tubular lengths interconnected by a threaded rod in the manner of the tension braces 210 in FIG. 21.

In all the space frames, the chords may be sealed to the stub/sleeves or posts and water circu¬ lated therethrough to give the frames a fire rating. During assembly the chords and braces are connected to the posts and the assembly may be effected at ground level before hoisting to the desired height. The tension braces may be tensioned on the ground or after raising the frame and may be tensioned to produce a ^'camber in the frames to-oppose any loads e.g. due to the weight of roof panels applied to the f ames.

The potential applications for the space frame of the present invention are almost infinite, aided by the ability to curve the frames in one or two directions as desired.

The advantages of the space frames, even existing space frames , will be readily apparent to the skilled addressee, who will also appreciate that the present invention is not limited to the embodi¬ ments disclosed by way of illustrative examples only

Claims

1. An adjustable space frame including: an upper grid of chords intersecting at a plurality of modes and a lower grid of chords intersecting at a plurality of modes wherein: at least one of the modes in the upper grid is connected to at least one of the modes in the lower grid by a tension and/or compression brace or strut, the length of the brace or strut being adjustable to apply- a curvature to the space frame and/or to vary the rigidity of the space frame.

2. A space frame according to Claim 1 wherein: the modes of the upper grid are connected to the modes σf the lower grid by posts to which the chords are connected.

3. A space frame according to Claim 2 wherein: a pair of diagonal tension braces inter¬ connect the chords or modes on an adjacent pair of posts in the frame.

4. A space frame according to Claim 2 wherein: a pair of diagonal tension braces inter¬ connect the chords or modes of a diagonally opposed pair of posts in the frame.

5. A space frame according to any one of Claims 2 to 4 wherein: the longitudinal and/or lateral chords of one of the grids are offset relative to the corresponding chords of the other grid and the posts are inclined to the vertical.

6. A space frame according to any one of Claims 1 to 5 wherein: the tension braces includes U-, D- or L- shaped brackets attachable to the chords or posts, the brackets being interconnected by tension rods or cables.

7. A space frame according to any one of Claims 1 to 5 wherein: the tension braces include tension rods received in holes in the chords or posts and having nuts threaded on the ends of the rods to apply tension to the rods.

8. A space frame according to any one of Claims 1 to 5 wherein: the tension braces include a pair of rods or tubes connected to the chords or posts , the rods or tubes being interconnected by a turnbuckle or threaded rod.

9. A space frame according to any one of Claims 2 to 5 wherein: the chords are engaged with stubs or sleeves on the post, or in holes or slots in the post and are connected thereto by fasteners which apply the loads between the chords and the stubs, sleeves or posts by shear forces in the fasteners.

10. A space frame according to any one of Claims 2 to 8 wherein: the chords are connected to the posts by tension rods provided internally in the chords engageable with the posts.

11. A space frame according to Claim 10 wherein: elastomeric compression washers are inter¬ posed between the ends of the chords and the adjacent posts to accommodate variation in tolerances in the components of the space fram .

12. A space frame according to any one of Claims 1 to 11 wherein: the grids may be interconnected by rigid braces on infill panels in one direction, with the tension braces interconnecting the grids in a second direction.

13. An adjustable space frame including: an upper grid of chords intersecting at a plurality of modes and a lower grid of chords inter- secting at a plurality of modes wherein: inclined posts or struts interconnect the modes of the grids and the longitudinal and/or lateral chords in the grids are adjustable in length to apply a curvature to the space frame and/or to vary the rigidity of the space frame.

14. A method for connecting the chords to a mode of a space frame including: a post at the mode; at least one stub extending from the post to engage a respective chord in the space frame; and means to connect the chord to the stub.

15. A method for connecting the chords to a mode of a space frame including: a post at the mode; at least one hole or slot in the post to receive a respective chord in the space frame; and means to connect the^' chord to the hole or slot in the post .