CA1218213A

CA1218213A - Modular construction

Info

Publication number: CA1218213A
Application number: CA000442873A
Authority: CA
Inventors: Robert H. Barrow
Original assignee: GEODOME SPACE FRAMES Pty Ltd
Current assignee: GEODOME SPACE FRAMES Pty Ltd
Priority date: 1982-12-09
Filing date: 1983-12-08
Publication date: 1987-02-24
Also published as: HK93986A; MY8700273A; SG70786G; GB2131847B; GB8332226D0; AU2177283A; GB2131847A; AU572478B2

Abstract

MODULAR CONSTRUCTION
ABSTRACT

A structure comprising a plurality of connectors, a plurality of elongated strut members extending between said connectors and affixed thereto by threaded fasteners extending longitudinally outwardly from said struts and threadably engaging the connectors.

Description

MODULAR ~CONSTRUCTIO~
~a~3~
The present invention relates to the modular construction of structures which comprise a network of interconnected struts and may be conveniently built up from a plurality of modular components. Such structures have become increasingly popular for roofing large areas such as warehouses, stadiums, public open space, shopping halls and the like as they may be fashioned to span large areas without central supporting columns. Such structures may be either load bearing or primarily decorative and have the capacity to form space frames which clear span in two directions.
Typically such structures are huilt up using a pluralit~v of standard or modular components. The components may comprise a plurality of elongated struts held in spaced relationship to one another by a plurality of connectors whereby to form a network of interconnected struts.
Numerous means of joining the connectors and struts to one another have been proposed but none have proved entirely satisfactory.
The connecting means should proviae for a secure connec-tion of adequate strength which is easy to assemble. For this reason it would be preferable for power tools to be usable for connecting the elements to form the network.
In addition the connection should preferably facilitate erection of an array in situ and thus be self aligning and self supporting.
Previously proposed modular building methods have not proved entirely satisfactory in all of these respects.
It is an object of the present invention to provide, in one embodiment, a structure formed from a plurality of modular components. It is also an object of the invention to provide in another embodiment a method of forming a structure from a plurality of modular components.
Still further o~jects of the invention will become apparent from the following description of the invention.
In one embodiment the present invention provides a structure comprising a plurality of elbngated strut members , extending between a plurality of connectors and affixed thereto by threaded bolts extending longitudinally outwardly from said struts and threadedly engaging the connectors.

~ ~v~

The strut members according to the invention may each comprise an elongated rod-like member. The rod-like member preferably includes a sleeve portion extending into the hollow section with the tapered portion extending longitudi-nally beyond the hollow portion. The rod-like member is preferably substantially annular in transverse cross-section along the majority of its length although other configurations are also envisaged as falling within the scope of the present invention.
A strut member according to the present invention may have a tapered end~piece at each of its ends. The end-piece may be integral with the remainder of the strut member or a separable portion thereof. The external surface of the end-piece may be of a substantially conical, domed or other substantially smooth external surface which tapers toward an outer extremity or nose.
The tapered ènd-piece may be formed in a variety of ways. For example, the strut member may comprise a pipe or other hollow section and the end-piece may include a sleeve portion extending into the hollow section with the tapered portion extending longitudinally beyond the hollow section.
The end-piece and hollow section may be secured to one another such as by welding, screw threads, adhesives or other means suitable for the securement and consistent with the materials Gf which the respective pieces are composed. The end-piece is preferably machined from a solid block.
The end-piece may have a bore for receiving a bolt or other pin-type ~astener so that the fastener may extend longitudinally outwardly from the strut member.
Preferably the inner face of the end-piece is funnel-like and an~led toward the bore. By this means the end of a bolt being fed through the bore from within the strut member is directed toward the bore opening thereby facilita-ting the insertion of a bolt into the bore. MoreovPr, the funne]-like inner face of the end-piece allows a powered wrench or like tool to be used in the assembly of the structure.
Preferably the bore comprises a first portion adapted to receive the head of the threaded fastener and a second portion of a reduced size relative to the first portion and ~0 adapted to receive the shank but not the head of the fastener;

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the second portion being positioned outwardly of said first portion, i.e. closer to the outer extremity or nose of the end-piece. Thus the head of a bolt may be at least partly housed within the first portion with the shank extending through the second portion and longitudinally outwardly of the strut member for threadedly engaging a connector according to the invention.
The outer surface o~ an end-piece according to the invention may be in the form of a cone. Conveniently the outer face is in the form of a truncated cone whereby the nose terminates in an annular mating face. The surface of the mating face may be substantially planar with the plane extending substantially normally of the longitudinal a~is of the strut member.
Preferably each elongated strut member further includes an access port positioned adjacent each end of the strut member whereby in use a threaded fastener may be passed through the access port into the interior of the strut member and positioned to extend through the bore. The access port may be substantially circular, oval or other convenient shape. Conveniently the access port is of a teardrop like shape with its longer axis extending along the strut member.
The broader end of the tear-drop may face toward the nearer end-piece of the strut.
To minimize the reduction in strength o~ the strut member the a~ess port should be of the smalles'~ practicab~e size. The radius of curvature of the broader end of a tear-drop shaped access port may accordingly be only marginally larger than that of the bolt head to be projected through the bore.
The access port may be provided with a cover. The cover preferably seals the port to minimize moisture access.
The cover may take the form of a grommett conveniently formed from metal, rubber or plastics materials.
The strut members provided by the invention may be formed from a variety of materials including steel, stain-less steel, plastics and aluminium. T~e choice of material will depend upon a number of factors including the function of the structures and the desired strength characteristics.
~0 When steel components are employed they may be -- 4 ~

protected against corrosion by galvanising, painting, po~der coating and other coatings.
A connector according to the present invention comprises an enclosed body having a plurality of threaded passages. The longitudinal axis of the threaded passa~es of each body all intersect at a single point. Preferably the body is substantially symmetrical in shape.
Substantially spherical bodies are preferred although faceted spheroids such as platonic and semi-platonic bodies and all shaped bodies are all considered as falling within the scope of the invention. The size of the body with respect to that of the strut members may be varied considerably. The extent of variation may be influenced by such factors as the number, angle, length, and diameter of the threaded passageways and the weight cost and structure of the body.
The angles between the passageways in any one connector may be varied to suit the geometry of the desired structure.
The connector body may be hollow or substantially solid and may be conveniently formed ~rom steel, aluminium, stainless steel or plastics materials. The selection of material for any particular application is dependent upon a number of factors including the desired structural strength indoor/outdoor applications, compatability with other components, and the like.
The outer surface of the body may be facetted in the region of the passagewa~s to provide a substantially planar mating surface about each passageway. A counter-bore or counter-sink may be provided at the entrance to each passageway to facilitate mating ~etween the connector and a strut member. The mating surface may be conveniently provided ~ithin the counter bore i.e. the mating surface may be below the outPr surface of the body.
In a structure according to the invention the nose of the strut may abut the connector. In an alternative arrangement a spacer may be interposed between the strut and the connector. Preferably the spacer is in the form of a sleeve having an internal diameter sufficient to allow free passage of a bolt therethrough. The external surface of the sleeve may be of the same cross sectional shape as tha-t of the strut. Preferably -the sleeve is subs-tantially cylindrical.
The end Eaces of -the sleeve may form a complemen-tary angle with the faces of the connector and stru-t with which they are to abut.
The nose of the strut member may be substantially planar with the plane being substantially normal -to the longi-tudinal axis. The end faces of the sleeve are preferably also substantially planar, with the plane being substantially normal to the longitudinal axis whereby to nes-t against the nose. In one arrangement a counter-bore or counter-sink may be pro-vided in the nose of the end--piece for receiving one end of a sleeve in accordance with the invention.
The optional counter-bore or counter-sink in the connector and/or nose may each be dimensioned to receive a separate end face of the sleeve.
The use of counter-bores or counter-sinks may serve to alleviate the bending and shear forces on the bolts in an erected structure according to the invention.
The rims of intersection between the end faces and longitudinal wall of the sleeve may each be chamfered.
The sleeve may be a separate component as described above. In an alternative arrangement the sleeve may be affixed to the end of the strut such as by welding or adhesives. In yet another embodiment the sleeve ma~ be formed as an integral part of -the strut end piece. In this arrangement the sleeve may appear as an extension of the nose of the end piece.
The bolt provided in accordance with the lnvention may have a partly or fully threaded shank. The head of the bolt may be shaped to receive a spanner or similar tool.
Preferably the head is substantially cylindrical with a socket provided in its top face. Such an arrangement facili-ta-tes tightening of the bolt using a wrench with a complemen-tary stud and a universal joint, the shank of the wrench projecting out of the strut through the access port. The shank of the wrench may be fitted with a handle for manual operation or may be coupled to an impact drill or similar power tool for rotation of the bolt.

A Eirst sealing member may also be provided in accordance with the invention. The member is preferably in the form of an O-ring which may be formed from elastomeric, polyurethane, rubber, neoprene or other resiliently deformable material. In use, the sealing member may surround -the shank of the bolt adjacent the nose of the strut. The inner rim of the nose and the abutting inner rim of the sleeve or other connector are preferably chamfered and the sealing member may conveniently be situated within the void so formed.
The sealing member may firstly serve the purpose of sealing the strut by acting as a barrier to moisture migrating along the bolt to the interior of a hollow strut.
The sealing member may secondly serve the puxpose of holding the bolt in place in the end of the strut prior to engagement with the connector.
A second sealing member may optionally be provided between the connector and the sleeve. Preferably a void is created to receive the sealing member in this location by chamfering the neighbouring rims. Where the sleeve is integral with the strut a single sealing member may be provided between the connector and the sleeve.
A seat or washer may be provided for the bolt in accordance with the present invention. The seat or washer may be adapted to receive the shank of the bolt or in-ternal diameter of the washer may be sufficient to allow passage of the shank or the bolt but retain its head. The washer may be positioned between the head of the bolt and the inner face of the end piece. The washer or seat may be of greater diameter than -the bolt head. The washer may be of a hardy material to reduce wear. For example the washer may be manufactured in a high tensile steel.
In use, the assembly of -the elements provided by the invention may be effected simply and positively as will now be described in rela-tion to one preferred embodimen-t.
The bol-t is inserted head firs-t through the access port with the head being directed up the tube away from the adjacent end-piece. When the bolt is wholly within the tube the tube is angled for the bolt -to fall by gravity -through the bore.

The washer or seat when presen-t may be positioned within -the end piece prior to insertion of the bolt. Alternatively, -the washer may be placed around -the shank of the bolt prior to its insertion into the end piece.
An O-ring is placed over the protruding shank of -the bolt~ The bolt is -thereby captured wi-thin the bore. The sleeve is then placed over the protruding shank and a wrench engages the socket in the head. The other end of the wrench is coupled to an impact drill. The shank of the bolt is entered into the desired passageway of the connector and the bolt rotated by the impact wrench to engage the threads of the passageway. The strut is thereby affixed to -the connector. A network of interconnected struts may be built up following the above described procedure by affixing a plurality of struts to each connector.
The present invention will now be more fully described with reference to the accompanying drawings. It should be unders-tood, however, that the following description is illustrative only and should not be taken in any way as superceding the generality of the preceding description.
In the accompanying drawings Figure 1 is a cut-away view of one possible form of elements according to the present invention.
Figure 2 is a schematic representation of one possible form of network incorporating an embodiment of a structure according to the present invention.
Figure 3 is a perspective view of an embodiment of the structure according to the present invention.
In more detail Figures 1 to 3 illustrate a structure according to the present invention comprising a plurality of connector~ 1 f~om which extend a plurality of elongated strut members 2 in a variety of networks. An example of such a ne-twork is illustrated in Figure 2.
The elongated strut members 2 include an access port 3 to assist in the assembly of the elements provided by the invention~. The elongated strut mernber 2 includes a tapered end piece 4 at each of its ends. the end piece may be secured to a hollow section of the elongated strut member in any suit--able manner. The end piece 4 includes a stepped bore 5 adap-ted to receive a bolt 6 and which commences in a countersunk end face 5A.

The bolt 6 thus extends longitudinally outwardly from the elongated s-trut member 2.
The bol-t 6 passes through a passage 7 in the form of a sleeve. The bolt -then is threadably connec-ted to a threaded passage 8 in the connector 1. As best illustrated in Figure 3 the outer surface of the connec-tor is faceted around -the threaded passage to provide a substantially planar mating surface for the passage 7 or elongated strut member 2. A
sealing member 10 in the form of an O-ring is provided on the shank of -the bolt 6 and is positioned between the nose of the end piece 4 and the passage sleeve 7. The inner rim of the nose and the abutting inner rim of the sleeve 7 are camphered to provide a void for the O-ring 10.
A washer 11 is provided between the head of the bolt 6 and the base of the bore 5.
Finally it is to be understood that various altera-tions, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention-

Claims

CLAIMS:
(1) A three-dimensional space frame structure comprising a plurality of elongated tubular struts or ties connected together at their ends through a plurality of connectors, each connector comprising a body having an outer face and a plurality of screw threaded bores, the axes of which intersect and are inclined to each other, the end of each strut or tie having an end piece pro-viding an end face and an axial passage which receives a bolt, the bolt having a head, which acts against the in-side of the end piece, and a shank, which is screwed into one of the screw threaded bores of one of the connectors to hold the end face on the end piece in mating engage-ment with the other face of the connector body surround-ing a bore into which the bolt is screwed, and each strut or tie having an access port in its wall adjacent the end piece to enable an implement to be engaged with the head of the bolt to rotate the bolt and screw it into the bore.
(2) A structure according to Claim 1 wherein the access port is of a tear-drop like shape with its longer axis extending along the strut, the broader end of the tear-drop like shape being adjacent the end piece.
(3) A structure according to Claim 2 wherein each strut has a tapered end piece at each of its ends, the passage extending through the end piece.
(4) A structure according to Claim 3 wherein each end piece includes a sleeve extending from a tapered por-tion, the passage extending through the sleeve.
(5) A structure according to Claim 4 wherein the inner face of the end piece is funnel-like and leads to the passage.
(6) A structure according to Claim 5 wherein the passage comprises a first portion adapted to receive the head of the bolt and a second portion of a reduced size relative to the first portion and adapted to receive the shank but not the head of the bolt.
(7) A structure according to Claim 6 wherein each body is generally spherical and the outer surface of the body is facetted in the region of the screw threaded bores to provide a substantially planar mating surface around each bore.
(8) A structure according to Claim 7 wherein each body further comprises a counterbore at the entrance to each bore to facilitate mating between the connector and the strut.
(9) A structure according to Claim 8 wherein each strut has a countersink in the nose of the tapering por-tion adjacent the sleeve member.
(10) A structure according to Claim 9 further comprising a sealing member which surrounds the shank of the bolt in each end piece.
(11) A structure according to Claim 10 wherein at least one of the inner rim of the nose of each elon-gated strut member and the abutting inner rim of the threaded passage of each connector is chamfered.
(12) A structure according to Claim 11 in which the sealing member is provided between the tapering por-tion and the sleeve member.
(13) A structure according to Claim 12 further comprising a washer surrounding the shank of the bolt adjacent the head thereof.