CAST NODES AND PATTERNS FOR THEIR PRODUCTION

Abstract: A pattern (1) from which cast nodes can be produced, the pattern including a central ring or disc (2) against which one or more stubs (3) abut at selected stations to enable nodes of differing annular geometries and/or stub diameter to be produced from the same pattern.

Description: CAST NODES AND PATTERNS FOR THEIR PRODUCTION This invention relates to cast nodes. Steel node structures are conventionally formed with welded plate node points typically at the intersection of tubular or box members. Cast steel nodes have been developed to improve the performance of such node points in relation to stress flow and fatigue during use. One object of this invention is to reduce the cost and weight of such cast nodes by minimising the size of the node and by making savings in pattern making costs According to the present invention in one aspect, there is provided a pattern from which cast nodes can be produced, the pattern including a central ring or disc SUBSTITUTESHEET against which one or more stubs may abut at selected stations to enable nodes of differing annular geometries and/or stub diameter to be produced from the same pattern. The ring or disc is preferably of circular form, other configurations may, however, be employed. The presence of the ring or disc also allows the adoption of standardised pattern equipment in which stub pattern pieces may be positioned at selected stations around the circumference of the central ring to allow for differences in stub spacings and angles. The weight of cast nodes in accordance with the invention is also minimised when compared with more conventional cast or fabricated nodes by intersecting the nodes onto a disc, preferably of annular construction. The node stubs may be wholly or partly conical in shape prior to their being connected to the central ring or disc, the whole then making up a single piece integrated casting. Nodes in accordance with the present invention differ from those proposed previously in that:- (a) the stubs connect to a central ring or disc; (b) the stubs need only to reduce in diameter for part of their circumference because they meet at the centre, i.e. the "pinching in" of the diameter need not be uniform around the circumference; (c) the reduction in diameter on any plane towards the node centre may follow an elliptical profile, a SUBSTITUTE SHEET circular profile or even a straight sided cone; and (d) variations in stub angle can readily be made during node manufacture by rotating the stub pattern pieces around the central ring pattern form. In another aspect there is provided a cast node including a central ring or disc from the external periphery of which project two or more stubs. The invention will now be described by way of example only with reference to the accompanying diagrammatic drawings in which:- Figure 1 is a sectional view of a node produced from a pattern in accordance with the invention taken along line I-I of Figure 2; Figure 2 is a section taken along line II-II of Figure 1; and Figure 3 is a section taken along line III-III of Figure 1. The node 1 illustrated in the drawings was produced from a pattern in accordance with the invention and includes a central ring 2 from which protrude four major stubs 3 which lie in a common plane. One or more secondary stubs 4 which lie outside the plane of the ring 2 are additionally provided. Other numbers of major and secondary stubs may be provided. The stubs 3,4 may either include interconnecting bores to produce savings in weight or may have blind or partially blind bores which together SUBSTITUTESHEET define a rigid diaphragm between the stubs for extra stiffness. Alternatively, the central ring 2 may include one or more projections lying in directions outside the plane of the ring which can be used for connecting additional members by welding, pinning or the like. The centre lines of the stubs 3,4 may all intersect at one point or be variously separated in their intersection points. As mentioned previously the illustrated node was manufactured from a pattern in accordance with the present invention which includes a standard central ring of the same size and shape as ring 2 and which is suitable for producing a plurality of different node configurations. The stubs of the pattern are of the same shape and size as the stubs 3, 4 and are produced from wood as separate pattern pieces which abut the ring to form the complete piece to be cast. The individual stub pieces are rotaatable selectively about the circumference of the central ring to provide for variations in stub angles using the same pieces of pattern equipment. The stub pattern pieces may be interchanged with ones of differing diameter. In this way, a standard piece of pattern equipment is used to produce nodes being differing stub angles and diameters, thereby greatly reducing pattern making costs. SUBSTITUTESHEET Once assembled, the cast node is produced from the pattern by a conventional sand casting technique. It will be appreciated that the foregoing is merely exemplary of cast nodes in accordance with the invention and that modifications can readily be made thereto without departing from the true scope of the invention. SUBSTITUTESHEET

Claims: Claims 1. A pattern from which cast nodes can be produced, the pattern including a central ring or disc against which one or more stubs abut at selected stations to enable nodes of differing annular geometries and/or stub diameter to be produced from the same pattern. 2. A pattern as claimed in claim 1 wherein the ring or disc is of circular form. 3. A cast node including a central ring or disc from the external periphery of which project two or more stubs. 4. A cast node as claimed in claim 3 wherein the central ring and stubs lie in a common plane. SUBSTITUTESHEET

Inventors: WOOD ANTHONY, WOOD, ANTHONY
Applicants: RIVER DON CASTINGS LTD, WOOD ANTHONY, RIVER DON CASTINGS LIMITED
Application year: 1993
Main classification: B22C7
IPC codes: B22C7, E04B1