Metal founding – Means to shape a forming surface – Pattern
Patent
1997-07-21
1999-03-23
Ryan, Patrick
Metal founding
Means to shape a forming surface
Pattern
164 45, 164249, B22C 700
Patent
active
058846867
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to 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 nodes by minimising the size of the node and by making savings in pattern making costs. Nodes in accordance with the invention are one piece castings whose stubs are formed onto a central ring or disc.
According to the present invention in one aspect, there is provided a pattern from which a node can be cast as a single integral piece, the pattern being characterised in that it includes a central ring or disc against which one or more stubs abut at selected stations to enable nodes of differing angular geometries and/or stub diameters to be produced from the same pattern.
The axis of the ring or disc is generally, but not always normal to the axes of the main stubs. 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.
SUMMARY OF THE INVENTION
According to the present invention in another aspect, there is provided a node cast as a single integrated piece characterised by a central ring or disc from the circumference of which extends two or more stubs, the axis of the central ring lying generally normal to the axis of each stub.
The weight of nodes in accordance with the invention is also minimised when compared with more conventional cast or fabricated nodes by intersecting the stubs onto a disc, preferably of annular construction. The node stubs may be wholly or partly conical or necked in shape at their point of connection with 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: normal to the axes of the main stubs. circumference because they meet at the centre, i.e. the "pinching in" of the diameter need not be uniform around the circumference; follow an elliptical profile, a circular profile or even a straight sided cone; and rotating the stub pattern pieces around the central ring pattern form.
In another aspect there is provided a case steel node characterised by a central ring or disc from the external periphery of which project two or more stubs.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will not be described by way of example only with reference to the accompanying diagrammatic drawings in which:
FIG. 1 is a sectional view of a node in accordance with the invention taken along line I--I of FIG. 2;
FIG. 2 is a section taken along line II--II of FIG. 1; and
FIG. 3 is a section taken along line III--III of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
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, and where the axis of the ring is normal to the plane of the main members. 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 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 variousl
REFERENCES:
patent: 3461635 (1969-08-01), Hugues
patent: 4115975 (1978-09-01), Bliss
patent: 4790172 (1988-12-01), Simensen et al.
patent: 5144830 (1992-09-01), Ferrotti et al.
Lin I.-H.
River Don Castings Limited
Ryan Patrick
LandOfFree
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