GB2132306A

GB2132306A - Space framework connection

Info

Publication number: GB2132306A
Application number: GB08333463A
Authority: GB
Inventors: Randall Griffin Satterwhite
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-12-22
Filing date: 1983-12-15
Publication date: 1984-07-04
Also published as: GB8333463D0

Abstract

Several linear keyways (4) of uniform cross section extend through a connector (1) and have axes defining the edges of a regular octahedron. Each keyway has an end opening through the exterior of the connector (1) into which a spline (20) extending linearly and transversely of the length of an elongated stringer (2) can be inserted to join an end of the stringer (2) to the connector (1) at any one of various fixed angular relationships. Several identical connectors (1) and stringers (2) are interconnected in this manner to form a skeletal space framework, e.g. composite girders, roof trusses, building frames. <IMAGE>

Description

SPECIFICATION Space framework connection The present invention relates to standardized connections used for joining elongated stringers in three-dimensional or space frameworks.

Known space frameworks having standardized connections include elongated structural members or stringers acting as beams, struts and ties and having adjacent end portions joined at preselected angles by separate connectors. Typical uses for the frameworks include composite girders or trusses spanning long distances or supporting skeletons for roofs or domes without any weightbearing internal posts.

The cost of manufacture, ease of assembly, disassembly or modification, and the variety of the frameworks that can be made usually are determined by the design of the connector. One known connector is in the form of a ball having several radially extending sockets. Corresponding end portions of adjacent stringers are inserted into the appropriate sockets and secured to the ball.

For example, the sockets and stringer ends may have complemental threads or the stringer ends may be welded in their appropriate sockets.

In another known connection, one leg of an angle bracket is bolted to an end portion of a stringer and the other leg of the bracket is bolted to a connector plate to dispose the stringer at the desired angle to one or more other stringers connected to the plate in the same manner.

The principal object of the present invention is to provide novel standardized connections for joining adjacent end portions of stringers in a space framework.

It also is an object to provide such a connection of simple design so that it is inexpensive to manufacture.

An additional object is to provide a versatile connection in a form that can be used for constructing space frameworks of different designs and for different uses.

A further object is to provide such a connection for two or more stringers at various selectible fixed angular relationships.

A further object is to provide such a connection enabling quick and easy assembly and disassembly or modification of a desired space framework.

Another object is to provide a connection that is strong and durable, even when the desired space framework has stringers in the form of wood poles.

Some of the foregoing objects can be accomplished by providing in a connection for a space framework, the improvement comprising the combination of: a connector having therein several elongated keyways arranged with their axes substantially defining the edges of a polyhedron, each of said keyways having at least one open end at the exterior of said connector; and an elongated structural member having an elongated spline, the length of said spline extending generally transversely of the length of said elongated structural member, said spline being fittable through the open end of any selected one of said keyways for joining said connector and said elongated structural member.

Others of such objects can be accomplished by providing a connector for joining adjacent end portions of adjacent elongated structural members in a skeletal space framework, said connector comprising a body having several elongated keyways arranged with their axes substantially defining the edges of a polyhedron, each of said keyways extending generally linearly through said body and having at least one end opening through the exterior of said body.

Others of such objects can be accomplished by providing in a connection for connecting elongated structural members in a skeletal space framework, the improvement comprising the combination of: a connector for joining adjacent end portions of adjacent elongated structural members, said connector having several elongated keyways arranged with their axes substantially defining the edges of a polyhedron, each of said keyways extending generally linearly through said connector and having at least one open end at the exterior of said connector; and fittings securable to the end portions of the elongated structural members to be joined by said connector, each of said fittings having an end portion forming a spline extending generally transversely of the length of its elongated structural member, said spline being fittable through the open end of any selected one of said keyways for joining said connector and such fitting.

Others of such objects can be accomplished by providing for use in a space framework forming a three-dimensional array of elongated structural members and having a connector for joining adjacent end portions of adjacent elongated structural members which connector includes several elongated keyways each extending through the connector and having at least one open end at the exterior of the connector, the improvement comprising an elongated fitting having a flat tang plate securable in an end portion of one of the elongated structural members and an elongated spline extending along an edge portion of said flat tang plate, said spline being fittable through the open end of any selected one of the connector keyways for joining the connector and the fitting.

A fuller understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawings, in which: Figure 1 is a top perspective of a connector in accordance with the present invention; Figure 2 is a top plan of such connector; Figure 3 is a side elevation of such connector; and Figure 4 is a central section through such connector taken along line 4-4 of Figure 1; Figure 5 is an exploded top perspective of the connector of Figure 1, illustrating the separate halves thereof; and Figure 6 is a plan of the interior side of one half of such connector; Figure 7 is a fragmentary top perspective of an end portion of a stringer in accordance with the present invention usable with the connector of Figures 1 through 6;Figure 8 is a somewhat diagrammatic, fragmentary, side elevation of such stringer end portion with parts broken away; Figure 9 is a somewhat diagrammatic, exploded, top perspective of the component parts of the stringer of Figure 7, namely, an elongated structural length and a separate fitting; and Figure 9a is a fragmentary top perspective of an alternate stringer fitting; Figure 10 is a somewhat diagrammatic, fragmentary, top perspective of the connector of Figure 1 and the stringer of Figure 7, illustrating the procedure for joining of the connector and stringer in construction of a space framework, with parts broken away; and Figure 11 is a fragmentary, enlarged, detail, transverse section showing the joint between adjacent stringers and a connector; Figure 12 is a diagrammatic top perspective of a representative space framework that can be made by use of the present invention;Figure 13 is a diagrammatic top plan of such framework; and Figure 14 is a diagrammatic side elevation of such framework; Figure 15 is an exploded top perspective of an alternative embodiment of a connector in accordance with the present invention, illustrating the separate halves thereof; Figure 1 6 is a plan of the interior side of one half of such connector; and Figure 1 7 is a central section taken along lines 17-17 of Figure 15, again showing the two halves of the connector in exploded relationship; Figure 18 is a fragmentary top perspective of an end portion of an alternative stringer in accordance with the present invention usable with the connector of Figure 15; and Figure 19 is a fragmentary side elevation of the stringer of Figure 18, with parts broken away; and Figure 20 is a central section through the connector of Figure 15, corresponding to Figure 17 but with the two halves of the connector joined, illustrating the connection of the stringer of Figure 1 8 to the connector of Figure 1 5.

The connection of the present invention is used in forming skeletal, three-dimensional or space frameworks of various types and for various uses.

In general, as indicated in Figures 10 and 11, the connector 1 shown in Figures 1 through 6 is used to join elongated structural members or stringers 2 of the type shown in Figures 7 through 9 for making a desired framework. Such framework can be used in construction of a building structure, such as by forming a composite girder or truss, a supporting skeleton for a roof or a dome, or a skeletal shell for an entire building structure.

Optionally, the assembled framework itself can be the final product, such as shown in Figures 12 through 14 which illustrate a children's playground structure. The miniaturized connector 1' and stringer 2' shown in Figures 1 5 through 20, while similar in design to the other disclosed connector and stringer, are intended to be used in making much smaller space frameworks, such as scale models, or simply as a construction toy.

The assembled connector 1 shown in Figures 1 through 6 is a hollow body formed by several, preferably twelve, substantially identical, peripheral ribs 3 joined at their ends and giving the connector the general appearance of a polyhedron, preferably a regular octahedron. A cylindrical bore or keyway 4 of uniform cross section extends linearly through each rib, parallel to but inward of its planar exterior edge 5. A narrow slot 6 extends longitudinally the full length of each rib 3 and communicates between the planar exterior edge 5 of the rib and the corresponding keyway 4.

The axes of the keyways precisely define the twelve edges of a regular octahedron having eight complemental, equilateral triangular faces. Each combination keyway 4 and slot 6 has at least one unobstructed end that opens through one of the six corners or apexes of the connector. In addition, a hole 7 extends radially through each apex of the connector.

As best seen in Figures 5 and 6, preferably the connector is formed of two identical halves 8 each in the general shape of a square pyramid having equilateral triangular sides. As best seen in Figure 4, the two connector halves are joined base-to-base to form the assembled connector by a bolt and nut 11 fitted, respectively, in countersunk relationship in the holes 7 through tips of the pyramid halves. The nut and the head of the bolt block the ends of the keyways 4 and the slots 6 opening at the tips of the pyramid halves, but the ends of the keyways and slots opening through the pyramid base corners remain unobstructed.

As best seen in Figure 5, a recess 9 is formed inward of each base corner of a connector half and of a shape complemental to the shape of the exterior of a hex nut 10 which is fitted in the recess. The recesses 9 of the two halves and the nuts 10 between them interlock to assure precise registration of the two halves as they are joined.

The keyways 4 and slots 6 extending along the pyramid base edges are formed partly in each connector half, as are the holes 7 extending radially through the pyramid base corners. Each such hole 7 is of a diameter at least slightly greater than the diameter of the threaded bore through a nut 10.

The stringer 2 shown in Figures 7 through 9 includes an elongated structural length 12 and a separate fitting 13 secured to each end portion of the structural length. In the embodiment illustrated, the structural length is a cylindrical wood pole having each of its end portions tapered frustoconically toward its tip. Acute planar bevels 14 in opposite sides of each tapered end portion extend to the narrow planar end 15 of the length.

Each such planar end is perpendicular to the axis of the length.

A narrow central through slot 16 extends inward from each length end 1 5 between the bevels 14. The stringer fitting 1 3 has a flat tang plate 1 7 snugly received in the slot 1 6 and, as best seen in Figure 8, secured therein by nails or pins 18 embedded in the tapered end portion of the structural length and extending through the tang plate. A narrow stem 19 of the tang plate projects outward from the planar end 1 5 of the structural length and ends in a larger, substantially cylindrical edge rib or spline 20 of uniform cross section extending generally linearly, transversely of the length.

Figures 3, 10 and 11 illustrate the interconnection of stringers 2 and a connector 1.

The diameter of each stringer spline 20 is slightly less than the diameter of each connector keyway 4, so that the stringer can be secured to the connector by sliding the spline and its stem 1 9 lengthwise through the open end of any one of the keyways and its slot 6 by movement of the stringer transversely of its length. It will be noted that the length of a spline is substantially the same or slightly less than the length of a keyway and that the thickness of the stringer stem is substantially the same as or less than the width of each connector slot 6. In addition, the planar end 1 5 of the stringer structural length 12 is closely adjacent to and of a width about the same as the planar exterior edge 5 of the adjacent connector rib 3.

When the spline is inserted fully into the keyway, any substantial swinging movement of the stringer relative to the connector is prevented by engagement of the stem 19 against a side of the connector slot 6. Should sufficient force be exerted to bend or bow the stem 19, the end 1 5 of the structural length 12 abuts against the exterior edge 5 of the connector rib 3 to prevent further relative movement. The angular relationship of the stringer and the connector is fixed with the axis of the stringer bisecting the dihedral angle between adjacent faces of the octahedron defined by the axes of the keyways.

After insertion of the one or more stringer splines into the appropriate connector keyway or keyways, the externally threaded shanks of pins or bolts 21 are inserted into the adjacent, radially extending connector holes 7 through the base corners of the pyramid halves. Such bolts are screwed tightly into the corresponding nuts 10 so that, as best seen in Figure 1 , the enlarged heads of the bolts block the ends of the keyways to prevent the stringer splines from the sliding out of their keyways.

Figures 12 through 14 illustrate diagrammatically a skeletal space framework constructed by the embodiment of the present invention shown in Figures 1 through 11 for use as a children's playground structure. The connector halves are cast aluminum alloy having keyways of a diameter of about .5 inch (12.7 mm), ribs of a length of about 3 inches (7.6 cm) and central slots of a width of about .2 inch (5.1 mm).

The width of the planar external edge of each connector is about 1 inch (2.5 cm) which corresponds approximately to the width of the planar end of each stringer structural length. The stringers 2 are wood poles of a main diameter of about 6 inches (15 cm) with their ends tapered generally frustoconically to a diameter of about 3 inches (7.6 cm). The stringer fittings have mild steel tang plates of a thickness of about .19 inch (4.8 mm) which allow use of a pneumatic nailer (Senco Model SN-IV) for driving a 2 inch (5.7 cm) 7 penny hardened steel nails into the tapered stringer end portions and through the tang plates of the fittings. The stringer splines are rolled steel cylinders of a diameter of about 44 inch (11 mm) joined to the fitting stems by welding.

Alternatively, as shown in Figure 9a, a cylindrical stringer edge rib or spline 20a can be formed integral with the flat steel tang plate 1 7 and stem 1 9 by rolling the narrower end portion of the fitting into a hollow cylinder, preferably with the plane of the tang plate intersecting the spline axis.

The framework shown in Figures 12 through 14 is constructed with all connectors oriented as shown in Figure 1 , that is, with opposite apexes of each connector at the top and bottom, respectively. Other orientations of the connectors can be used, such as arranging opposite connector edges at the top and bottom, but the versatility of the connection of the present invention can be indicated by describing the fixed angular relationships permitted with reference to the framework shown in Figures 1 2 through 14.

Since each connector has twelve keyways, an end portion of a stringer can be connected to adjacent end portions of up to eleven other stringers. "Reference" stringer 2R shown in Figures 12 through 14 extends horizontal and has one of its ends connected to stringers 2A, 2B, 2C and 2D (directly behind stringer 2C as viewed in Figure 12) joined by the connector 1 R. Stringers 2A and 2B make angles of 120 degrees, respectively, with stringer 2R and an angle of 60 degrees relative to each other. Stringers 2C and 2D make angles of 60 degrees, respectively, with stringer 2R and an angle of 60 degrees relative to each other.Up to seven other stringers could be connected to stringer 2R by connector 1 R as follows: four stringers collinear, respectively, with stringers 2A, 2B, 2C and 2D but projecting oppositely from them and flaring upward from the connector; one stringer collinear with stringer 2R and extending oppositely from the connector; and two collinear, oppositely extending, horizontal stringers each disposed at an angle of 90 degrees to stringer 2R.

Various planes containing four or six stringers radiating equiangularly from connector 1 R are defined by the twelve possible stringers that can be connected by such connector. Stringers 2A and 2D, and the possible stringers projecting oppositely from and collinear with stringers 2A and 2D, respectively, define a first vertical plane containing these four mutually orthogonal stringers. Similarly, stringers 2B and 2C and the possible stringers collinear with and projecting oppositely from them define a second vertical plane containing those four mutually orthogonal stringers. Stringer 2R, the possible stringer collinear with and projecting oppositely from it and the two oppositely extending horizontal stringers perpendicular to it define a horizontal plane containing those four mutually orthogonal stringers.Each of the first and second vertical planes and the horizontal plane is perpendicular to each of the other two planes.

In addition, there are four different planes each containing six stringers radiating from connector 1 R, adjacent stringers having an angle of 60 degrees between them in each instance. One of such planes contains stringers 2R, 2A and 2C and the possible stringers collinear with and projecting oppositely from them; another of such planes contains stringers 2R, 2B and 2D and the possible stringers collinear with and projecting oppositely from them; one of such planes contains stringers 2A and 2B, the possible stringers collinear with and projecting oppositely from them, and the possible oppositely-projecting horizontal stringers perpendicular to stringer 2R; and the last such plane contains stringers 2C, 2D, the possible stringers collinear with and projecting oppositely from them, and the possible oppositely-projecting horizontal stringers perpendicular to stringer 2R.

Considering the various selectible fixed angular relationships between adjacent stringers permitted by the connection of the present invention, the variety of space frameworks that can be made is limited only by the imagination of the user. The sliding connection of stringers to connectors affords quick and easy assembly and disassembly of a desired space framework, and also permits modification of the framework by adding and/or rearranging stringers without necessarily destroying the structural integrity of the remainder of the framework.

As noted above, the embodiment of a connection in accordance with the present invention shown in Figures 1 5 through 20 is intended to be used in making miniaturized space frameworks but its design is very similar to the design of the previously described embodiment.

The miniaturized connector 1' is a solid body, rather than being hollow, and has 12 substantially identical, planar exterior edges 5' corresponding to the exterior edges 5 of the ribs 3 of the previously described embodiment. Such edges 5' are disposed generally in regular octahedral relationship. A cylindrical keyway 4' of uniform cross section extends linearly, parallel to and inward of each planar exterior edge 5' and has opposite ends opening through the corners or apexes of the connector. A narrow central slot 6' extends longitudinally the full length of each edge 5', communicates between the corresponding keyway 4' and the exterior of the connector and has unobstructed opposite ends opening through the corners or apexes of the connector. A blind bore 7' extends radially inward from each such corner or apex.Preferably, the axes of the keyways precisely define the twelve edges of a regular octahedron having eight complemental equilateral triangular faces.

As in the previously described embodiment, the connector 1' is formed of two identical halves 8' each in the general shape of square pyramid having complemental equilateral triangular sides.

The keyways 4', slots 6' and blind bores 7' along the pyramid base edges and at the pyramid base corners are formed partly in each connector half.

The connector halves 8' do not have any recess corresponding to the recesses 9 of the previously described embodiment. Rather, substantially complementally shaped, triangular projections 22 and recesses 23 are formed at opposite sides, respectively, of a diagonal between opposite corners of each pyramid base so that, as best seen in Figures 1 7 and 20, the projections and recesses interfit as the two halves are brought together to assure precise registration of the two halves.

Preferably, the connector is molded plastic material and the two halves can be conveniently cemented together.

The miniaturized stringer 2' shown in Figures 18 and 19 is of the same general design as the stringer 2 shown in Figures 7 through 9. Each end portion of a cylindrical, structural length 12' is tapered frusto-conically towards its tips and each tip portion has acute planar bevels 14' in its opposite sides that end at a narrow planar end 15' of the length 12'. In the stringer 2', however, the narrow stem 19' projecting outward from the structural length between the bevels 1 4' and the linearly extending cylindrical edge rib or spline 20' of uniform cross section supported on the stem are integral with the structural length. Preferably, the integral stringer 2' is molded plastic material.

The relative proportions of the connection components and the manner of interconnection of the stringers 2' and the connectors 1' is substantially the same as that for the previously described embodiment. A stringer may be moved transversely of its length to slide its spline and stem through the open end of a desired keyway and slot to the position indicated in Figure 20. For retaining the stringer spline in the slot, the cylindrical shanks of plastic pins or plugs 21' can be manually pressed into the blind bores 7' straddling the appropriate keyway. The plugs have enlarged heads that can be grasped to remove the plugs from the connector for quick and easy disassembly or modification of a constructed skeletal space framework. In addition or alternatively, the keyways or splines could be tapered to provide a fit sufficiently snug that a reasonably stable framework could be assembled without using plugs for blocking the ends of the keyways.

The embodiment of Figures 1 5 through 20 is particularly useful for making scale models of larger frameworks that can be made by use of the present invention, such as by the first described embodiment. In either embodiment, the connection of the present invention is strong and durable over a long period in a permanent framework or after repeated use in temporary frameworks.

Claims

1. In a connection for a space framework, the improvement comprising the combination of: a connector having therein several elongated keyways arranged with their axes substantially defining the edges of a polyhedron, each of said keyways having at least one open end at the exterior of said connector; and an elongated structural member having an elongated spline, the length of said spline extending generally transversely of the length of said elongated structural member, said spline being fittable through the open end of any selected one of said keyways for joining said connector and said elongated structural member.

2. In the connection defined in claim 1, the keyways being of substantially uniform cross section and extending generally linearly through the connector and the spline being of substantially uniform cross section and extending generally linearly, transversely of the length of the elongated structural member.

3. In the connection defined in claim 1 or claim 2, the cross-sectional shape of the spline being substantially complemental to the cross-sectional shape of the selected keyway.

4. In the connection defined in claim 1, claim 2 or claim 3, the axes of the keyways defining the edges of a regular polyhedron.

5. In the connection defined in claim 4, the axes of the keyways defining the edges of a regular octahedron.

6. In the connection defined in any preceding claim, the improvement further comprising means for blocking the open end of the selected keyway after the spline has been inserted so as to prevent the spline from being withdrawn from the keyway.

7. In the connection defined in claim 6, the connector having bores through the apexes of the polyhedron defined by the keyway axes and the blocking means including pins insertable into said bores.

8. In the connection defined in any preceding claim, the improvement further comprising a narrow slot extending lengthwise of the selected keyway and communicating between such keyway and the exterior of the connector, and the elongated structural member including an elongated structural length and a thin, substantially flat stem projecting from an end of said elongated structural length, said stem carrying the spline and being slidable in said slot as the spline is inserted into the selected keyway.

9. In the connection defined in claim 8, swinging movement of the elongated structural member relative to the connector being limited by engagement of the stem with a side of the slot.

10. In the connection defined in claim 8 or claim 9, the elongated structural length having a substantially planar end adjacent to and extending substantially parallel to the length of the spline, and the connector having a substantially planar exterior edge extending substantially parallel to the length of the selected keyway, said substantially planar end of the elongated structural length and said substantially planar exterior edge of the connector being closely adjacent when the spline is inserted into the selected keyway.

11. In the connection defined in any preceding claim, the elongated structural member being in substantially fixed angular relationship to the connector when the spline is fully inserted into the selected keyway.

12. In the connection defined in claim 11, the axis of the elongated structural member substantially bisecting the dihedral angle between adjacent faces of the polyhedron defined by the axes of the connector keyways when the spline is fully inserted into the selected keyway.

13. In the connection defined in any preceding claim, the connector being formed of two halves each having a base abuttable against the base of the other connector half, at least one of the connector keyways being formed partly in each of said connector halves.

14. In the connector defined in claim 13, the two connector halves including substantially complemental interfitting projections and recesses.

1 5. In the connection defined in claim 13 or claim 14, the connector halves including respective recesses registered with each other, and the improvement further comprising aligning means fitted in the recesses between the two halves.

1 6. In the connection defined in any preceding claim, the connector being a hollow body formed of substantially identical ribs joined at their ends, the connector keyways extending lengthwise through said ribs, respectively.

1 7. In the connection defined in any preceding claim, the elongated structural member including an elongated structural length and a separate fitting securable to an end portion of said length.

1 8. In the connection defined in claim 17, the elongated structural length having a through slot in an end portion thereof and the fitting including a flat tang plate secured in said slot for connecting the fitting to the elongated structural length.

1 9. In the connection defined in claim 17 or claim 18, the elongated structural length being a solid wood pole.

20. In the connection defined in any of claims 1 through 16, inclusive, the elongated structural member including an elongated structural length and a thin, substantially flat stem projecting from an end of said length and carrying the elongated spline, the spline and said stem being integral with said length.

21. A connector for joining adjacent end portions of adjacent elongated structural members in a skeletal space framework, said connector comprising a body having several elongated keyways arranged with their axes substantially defining the edges of a polyhedron, each of said keys extending generally linearly through said body and having at least one end opening through the exterior of said body.

22. In a connection for connecting elongated structural members in a skeletal space framework, the improvement comprising the combination of: a connector for joining adjacent end portions of adjacent elongated structural members, said connector having several elongated keyways arranged with their axes substantially defining the edges of a polyhedron, each of said keyways extending generally linearly through said connector and having at least one open end at the exterior of said connector; and fittings securable to the end portions of the elongated structural members to be joined by said connector, each of said fittings having an end portion forming a spline extending generally transversely of the length of its elongated structural member, said spline being fittable through the open end of any selected one of said keyways for joining said connector and such fitting.

23. For use in a space framework forming a three-dimensional array of elongated structural members and having a connector for joining adjacent end portions of adjacent elongated structural members which connector includes several elongated keyways each extending through the connector and having at least one open end at the exterior of the connector, the improvement comprising an elongated fitting having a flat tang plate securable in an end portion of one of the elongated structural members and an elongated spline extending along an edge portion of said flat tang plate, said spline being fittable through the open end of any selected one of the connector keyways for joining the connector and the fitting.

24. A connection for a space framework substantially as described hereinbefore with reference to the accompanying drawings.

25. A connection according to Claim 24 and as illustrated in Figures 3, 8, 10 and 11 to 14 or 20 of the accompanying drawings.

26. A connector for joining adjacent end portions of adjacent elongated structural members in a skeletal space frame substantially as described hereinbefore with reference to the accompanying drawings.

27. A connector according to Claim 26 and as illustrated in Figures 1 to 6 and 10 to 14 or in Figures 1 5 to 17 and 20 of the accompanying drawings.

28. An elongated fitting for use in a space framework substantially as described hereinbefore with reference to the accompanying drawings.

29. An elongated fitting according to Claim 28 and as illustrated in Figures 3, 7 to 9, and 10 to 14, or modified as illustrated in Figure 9a, or as illustrated in Figures 1 8 to 20 of the accompanying drawings.

30. Any other novel feature or combination disclosed hereinbefore or in the accompanying drawings.