US3861107A

US3861107A - Connecting fixture assembly for space frame system

Info

Publication number: US3861107A
Application number: US363368A
Authority: US
Inventors: Hristo V Papayoti
Original assignee: Unistrut Corp
Current assignee: Unistrut International Corp; Unistrut Corp
Priority date: 1973-05-24
Filing date: 1973-05-24
Publication date: 1975-01-21
Anticipated expiration: 1992-01-21
Also published as: BR7404290D0; NL7406878A; GB1476473A; DE2425279A1; AU6908574A; FR2230931B3; CA1007823A; BE815486A; FR2230931A1

Abstract

A connecting fixture assembly used in a space frame system of the type wherein an upper chord frame and a lower chord frame structure are formed of a plurality of strut members connected to each other and held together by a plurality of connecting fixtures. In each case, the struts used have an extending lug and hole arrangement which prealigns them with the connecting fixtures to insure accuracy of assembly and further to add to the resistance of the struts to tension, compression, and torsional load. A connecting fixture assembly is employed which uses a pair of connecting fixtures including a standard connecting fixture having lugs and holes engageable with those of standard struts and a second stacking connecting fixture assembled in back-toback relationship with the standard connecting fixture and having a plurality of through holes, each registerable with the opposed lugs and holes of the standard connecting fixture. The relative sizing of the holes and lugs allows the final attachment of the struts to the connecting fixture by registering their standardized lug and hole aligning end portions to the face of either of the two connecting fixtures.

Description

United States Patent [191 Papayoti [451 Jan. 21, 1975 CONNECTING FIXTURE ASSEMBLY FOR SPACE FRAME SYSTEM [75] Inventor: Hristo V. Papayoti, Ann Arbor,

Mich.

[73] Assignee: Unistrut Corporation, Wayne, Mich.

[22] Filed: May 24, 1973 211 Appl. No.: 363,368

[52] U.S. Cl 52/650, 52/648, 403/171,

403/172, 403/178 [51] Int. Cl E04h 12/10 [58] Field of Search 52/648, 633, 650, 651,

52/652, 655, 263, 758 B, 758 C, 758 D; 403/13,14, 174, 178, 217,176,171, 172

Primary ExaminerErnest R. Purser Assistant Examiner-Henry Raduazo Attorney, Agent, or Firm-Hauke, Gifford, Patalidis & Dumont [57] ABSTRACT A connecting fixture assembly used in a space frame system of the type wherein an upper chord frame and a lower chord frame structure are formed of a plurality of strut members connected to each other and held together by a plurality of connecting fixtures. In each case, the struts used have an extending lug and hole arrangement which prealigns them with the connecting fixtures to insure accuracy of assembly and further to add to the resistance of the struts to tension, compression, and torsional load. A connecting fixture assembly is employed which uses a pair of connecting fixtures including a standard connecting fixture having lugs and holes engageable with those of standard struts and a second stacking connecting fixture assembled in back-to-back relationship with the standard connecting fixture and having a plurality of through holes, each registerable with the opposed lugs and holes of the standard connecting fixture. The relative sizing of the holes and lugs allows the final attachment of the struts to the connecting fixture by registering their standardized lug and hole aligning end portions to the face of either of the two connecting fixtures.

17 Claims, 7 Drawing Figures 2,1 94 ey, i m

PATENTED U 3.861.107

SHEET 1 [IF 2 PATENTEI] JAN 21 I975 SHEET 2 0F 2 CONNECTING FIXTURE ASSEMBLY FOR SPACE FRAME SYSTEM BACKGROUND OF THE INVENTION I. Field of the Invention The present invention relates to building constructions of the space frame type and more particularly to an improved connecting fixture assembly for use in space frames.

II. Description of the Prior Art The C. W. Attwood U.S. Pat. No. 3,270,478, C. W. Attwood et al. U.S. Pat. No. 3,421,280, and H. V. Papayoti U.S. Pat. No. 3,443,348, all of which are of common ownership herewith, disclose a system of space frame construction involving the use of lightweight interchangeable elements manufactured to close tolerances and designed to be assembled at extremely low cost even by relatively inexperienced workers to form structures varying in design and capable of being readily disassembled, altered, or expanded to meet the changing needs of the user, the components being almost 100 percent salvageable. Such a flexible type of structural framework is well suited for many different types of building, pavilions, three dimensional trusses, structural spans and the like.

As disclosed in the aforesaid patents, a space frame is a structure in which forces act in three or more directions in space. The structure uses four substantially standardized basic parts; namely, connecting fixtures, struts, bolts and nuts. The essence of the four basic parts is a preformed universal type connecting fixture having both horizontally and angularly disposed faces with accurate locating and securing means to which the struts may be fastened by nuts and bolts. The space frame systems can be applied in assembly roof span constructions as well as floors and other structures. Until the appearance on the market of space frames, known by the trademarks UNISTRUT and ATTWOOD SYSTEM, trusses and the like, used in roofs, floors and other building structures were either welded together and carried to the construction site or assembled by welding, riveting or bolting in the field. A problem arises in limiting the design of the four basic components to a very restricted number of variations so that the struts, for example, used in the chord frames and the struts used in the web frames all may have the identical construction. Standardization of the parts again presents additional problems when the space frames are of the multiple deck type which will be further discussed hereinafter.

SUMMARY OF THE INVENTION The present invention relates to a space frame system and to a connecting fixture assembly in which a stacking connecting fixture is readily combined with a stan' dard connecting fixture to provide for multiple-decked space frame assembly when this is required or to provide for pyramidal column capitals or raised space frame portions or the like. The connecting fixture assembly provides a back-to-back mounting arrangement to which may be attached a single type of strut used for the several chord frame and web frame parts.

The invention more particularly comprises a stacking connecting fixture for use with standard connecting fixtures in back-to-back relationship with an arrangement of appropriately sized mating lugs and holes which allows use of a standardized strut in both web and chord I frames such struts being attachable to either face of the pair of assembled connecting fixtures. It is possible to use struts with lugs engaging both sides of a connecting fixture assembly when it is constructed in accordance with the teachings of the present invention. This adds greatly to the load carrying capacity of the strut assembly in tension and in compression and consequently increases the load bearing capacity of the space frame structure.

Other objects, advantages and applications of the present invention will become apparent to those skilled in the art of space frame structures when the accompanying description of the present invention is read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The description herein makesreference to the accompanying drawings wherein like reference numerals refer to like parts where they may occur throughout the several views and in which:

FIG. 1 is a diagrammatic fragmentary side elevational view of a space frame structure in which the connecting fixture assembly made according to the present invention is of particular importance;

FIG. 2 is a fragmentary perspective view showing a connecting fixture assembly constructed in accordance with the teachings of the present invention and with several web struts attached;

FIG. 3 is a vertically spread perspective view showing the two main parts of the connecting fixture assembly;

FIG. 4 is a side elevational view partly in section showing the two part assembly with chord struts being attached to it in accordance with the present invention;

FIG. 5 is an exploded view showing the upper portion of the connecting fixture assembly with preferred aligned strut, locking bar and nut and bolt fastener prior to their assembly one to the other;

FIG. 6 is a vertically opened perspective view showing a different embodiment of the present invention utilizing a three part flat plate connecting fixture and a like constructed stacking connecting fixture; and

FIG. 7 is an elevational view partly in section showing a back-to-back connecting fixture assembly using fixtures of the type shown in FIG. 6.

DETAILED DESCRIPTION Referring now to the drawings and more particularly to FIG. 1, there is shown the basic construction of a space frame structure in which there is included a double deck arrangement with a pair of space frames having in common an intermediate chord frame. The upper space frame includes an upper chord frame structure A, and a lower chord frame structure A held together in spatial relationship by way of an intermediate web structure A The lower space frame structure includes at its upper chord frame the chord frame first above identified as the chord frame A The lower chord frame of the lower space frame and the intermediate web structures are identified by the numerals A and A respectively.

It will be understood that while the multiple-decked space frame system is shown as having only two vertical space frames, it may as well include an even greater number of space frames in accordance with the load requirements of the application. The connecting struts in the several chord frame structures are identified by the numerals 10, while those in the intermediate web structure are indicated as struts 12.

FIGS. 2 and 4 show the manner in which several upwardly and downwardly diagonally extending web struts 12 and chord struts are mounted on and attached to a connecting fixture assembly. Each of the struts l0, 12 used in the web structure and in the chord frame structure normally includes at its end a central hole 14 and a pair of outwardly disposed lugs 16 spaced on opposite sides of each hole 14. Each lug 16 has formed behind it a complementary coined recess 16a of similar cross-sectional size. The mode of construction and relative sizing of the lugs and holes in the struts 12 and likewise in the struts 10 is clarified in FIG. 4. The connecting fixture assembly of the back-to-back connectors is indicated generally by the numeral 18. The lower of the two plates 20 represents a stacking connecting fixture and is shown in back-to-back relationship with the upper of the two plates 22 which represents a standard connecting fixture. The general arrangement of both of the connecting fixtures includes a plurality of spaced, angularly sloped faces 24 to which are attached the several diagonal or web struts 12 and a second plurality of spaced, relatively flat and horizontally disposed faces 26 to which are attached the respective chord struts 10 which lie in the several horizontal chord frames A,, A and A as illustrated in FIG. 1. Each angularly shaped face 24 is spaced from the adjoining horizontal face 26 by a gusset 23. The standard connecting fixture plate 22 includes in each angularly sloped face 24 a pair of lugs 17 and a central opening 19. It will be understood that the web struts 12 are attached to the lower connector fixture 20 as illustrated in FIG. 2.

FIG. 3 shows the differences in the aligning arrangement as between the two connecting

fixtures

20 and 22. It will be seen that the lower stacking connecting fixture 20 has a plurality of through hole openings 28, three in number, formed in each of its flat or horizontal faces 26. To be registered in alignment with these are the aligned portions of the upper connecting fixture 22 including a plurality of outwardly extending lugs 30 arranged in pairs at both sides of each bolt hole 32. As previously shown in FIG. 2, the angularly disposed faces 24 of the upper fixture plate 22 include the lugs 17 and the intermediate opening 19. When the lower and

upper fixture plates

20 and 22 are placed in backto-back relationship prior to their attachment one to the other, and to the associated struts 10 and 12, it will be seen that the downwardly extending lugs 30 of the upper fixture plate 22 will be in each case aligned with the opposed openings 28 formed in the lower stacking fixture plate 20. The assembled parts are shown in FIG. 4 which further clarifies the manner in which the chord struts 10 are finally connected with respect to the flat or horizontally disposed faces 26 of both the upper and lower connecting fixtures. It will be seen that the struts 10 are preferably of a general channel shaped type and have a fastener nut 33 and bolt 34 fastened through their openings 14 and the

holes

32 and 28 in the connecting fixtures.

In the assembled position as illustrated in FIG. 4 it will be seen that the lower stacking fixture 20 is registered in proper position with the upper standard connecting fixture 22 through its downwardly extending lugs 30 registering with the openings 28 formed in the lower connector 20. The thickness of the plate at the horizontal face portion 26 of the lower stacking connecting fixture 20 is approximately twice the raised height of the opposed lugs 30. This leaves a lower surface pattern of openings 31 adapted to receive a strut 10 for attachment to the lower horizontally disposed faces 26 of the fixture 20. The center hole 28 is thus left aligned with the upper hole 32 to permit fastening of the two fixture plates together through a suitable fastener. The double back-to-back struts 10 shown at the center of the assembly 18 demonstrate the manner in which they are held together to the connecting

fixtures

20, 22 by a nut 33 and bolt 34 passing through the aligned strut hole 14 and the connecting fixture holes 28 and 32. At the right hand side of FIG. 4 drawing, a chord strut 10 is shown just prior to its being assembled to the lower face 26 of the lower fixture 20. The strut includes a pair of lugs 16 extending from its upper surface and tightly engageable with the opposed opening 31, left in the lower connecting fixture 20. To permit the fastening to the two

fixtures

20 and 22 together as well as the fastening of the strut 10 to the

fixtures

20, 22, there is included the intermediate hole 14 at the end of the strut 10 which is alignable with the

holes

28 and 32 formed through each horizontal face 26 of the upper fixture 22 and the lower fixture 20, respectively. A second strut 10 may be attached to the opposed horizontal surface of the upper fixture 22. It will be seen that a coined recess 30a of sufficient size is provided behind each lug 30 to engage tightly lugs 16 of the attached strut 10.

FIG. 5 shows the upper half of a connecting fixture assembly 18, namely the upper connecting fixture 22. A chord strut 10 is shown above the connecting fixture 22 preparatory to assembly. It will be understood that the same downwardly extending pattern of lugs 16 and intermediate opening 14 is provided near the end of the strut 10 as illustrated in FIG. 4. To complete the assembly there is included a reinforcing bar 50 which has a central depressed or flat portion 52 and includes three bolt openings 54 spaced along its length. The reinforcing bar 50 is included in the fixture assembly to further rigidify the assembly of struts 10 and connecting fixture assembly 18 thus to increase the capacity of the space frame. It will be understood that the reinforcing bar 50 may be in the form of a cross bar. The fastening of the connecting assembly 18, strut l0 and reinforcing bar 50 is completed by a plurality of nuts 33 and bolts 34 as illustrated.

FIGS. 6 and 7 show a different embodiment of the present invention in which the two back-to-

back connecting fixtures

60 and 80 are embodied in the form of separate multiple plate welded parts. Included in the upper connecting fixture 60 are a pair of orthogonally disposed

vertical plates

62 and 64 both of which are mounted on a base plate 66. The

vertical plates

62 and 64 have downwardly extending tabs 67 which fit into opposed mating recesses 68 formed in the base plate 66 to receive them in properly aligned relationship. The vertically oriented

plates

62 and 64 further have central cut out portions 70 and 72 which are best shown in FIG. 7. The two

vertical plates

62, 64 are thus registered one in the other and finally connected to the base plate 66 prior to a weld being applied to hold the three in tightly assembled relationship. The weld 61 may be applied as shown along the lines of intersection between the two vertically

upstanding plates

62, 64 and the base plate 66 and further to the bottom of the base It will be seen that the lower connecting fixture 80 is substantially similar to the upper connecting fixture 60 with respect to the parts, namely the vertical upstanding portions 82 and.84 which are fitted one in the other and to the lower base plate 86, which plate is adapted to be registered in back-to-back relationship with the base plate 66 of the upper connecting fixture 60. For this purpose and in a like manner to the apparatus of FIGS. 1-5, there is provideda plurality of openings 88 extending through the lower base plate 86 which register with downwardly projecting lugs 90 projecting downwardly from the lower surface of the upper base plate 66. A central through hole 92 is formed through the base plate 66 in alignment with ,each central opening 88 in the base plate 86 to admit attachment of the two plates and their associated struts by a suitable bolt and nut fastener. The lower connecting fixture 80, which is of a stacking connector type, has its

vertical plates

82 and 84 similarly aligned with the base plate 86 by means of a plurality of tabs 94 extending into recesses 96 formed through the base plate 86. Each of the vertically

upstanding plates

62, 64 in the upper fixture 60 correspond to

plates

82, 84 in the lower fixture 80.

FIG. 7 shows the assembled relationship of the upper and lower connecting

fixtures

60 and 80 respectively. The upper fixture 60 has formed on its

vertical plates

62, 64 an arrangement of lugs 98 and a central opening 100 in a manner substantially similar to the arrangement of lugs 17 and holes 19 on the angularly disposed surfaces 24 of the embodiment shown in FIGS. 25. This arrangement of lugs and openings is adapted again to register with corresponding lugs and openings formed in the diagonally positioned web struts 12 which are connected to the vertically upstanding members of the two connecting

fixtures

62, 64 and 82, 84. Also shown in FIG. 7 is the detail of the back-to-back relationship existing between the

horizontal surfaces

102 and 104 of the two

base plates

66 and 86. In a like manner to the FIG. 4 embodiment, the downwardly extending lugs 90 in the upper plate 66 extend into the lower holes 88 of the lower plate 86 in properly aligned relationship. The height of the lugs 90 is substantially less than the thickness of the base plate 86 of the lower fixture 80 so that there is left an opening 106 which allows the connecting of a lower chord strut with its protruding and upwardly extending lugs 16, as shown in FIG. 4. The opening 88 provided in the lower base plate 86 is further aligned with the opening 92 provided in the upper base plate 66 so that a suitable bolt and nut fastener of the type illustrated in FIGS. 4 and 5 may be used to assemble the two

base plates

66, 86 and their corresponding struts together. It will likewise be seen that provision is made for attaching an additional strut 10 to the upper surface of the upper fixture 60 by reason of the recesses 108 coined behind each of the lugs 90 in the upper base plate 66. These openings are of a sufficient size to receive in tight engagement a mating lug 16 extending from an associated strut 10 after the manner shown in FIG. 4. Thus it will be seen that it is possible in the assembly of FIG. 7 to assemble struts 10 to either or both the upper and lower surface of the

base plates

66, 86. It is possible to attach web struts 12 in accordance with the pattern of lugs 98 and openings 100 in the upper fixture 60 or with lugs 110 and openings 112 provided in the lower fixture 80.

-It will thus be understood that the present invention represents an improved connecting fixture assembly which is adapted for use in multiple-decked space frames, in pyramidal column capitals, or raised spaceframe portions or the like. By reason of the arrangement and sizing of the mating holes, lugs, and recesses in the upper connecting fixture relative to the lower connecting fixture and the double lug type attachment of struts to both sides of the connecting fixture assembly, it is possible to increase substantially the strength of the space frame structure.

What is claimed is:

1. A space frame system framework comprising a plurality of elongated stress and load transmitting struts interconnected by stress and load distributing fixtures to define upper and lower grid like chord frame structures disposed in spaced parallel planes; a plurality of elongated stress'and load transmitting struts, each connected respectively with the fixtures of the upper and lower chord frame structures; means for fastening said struts to said fixtures, said frame work further comprising a double deck arrangement of said chord frames wherein there is an uppermost and a lowermost chord frame and a common intermediate chord frame between the two, said fixtures in said intermediate chord frame comprising an upper and a lower connecting fixture, each having alternate angularly and horizontally disposed strut attachment faces, each of said horizontally disposed faces in one of said fixtures having a plurality of through holes radially thereon, said other fixture plate having on each of its horizontally disposed faces an alternating arrangement of lugs and holes in opposed relationship with said through holes of the other fixture, with the lugs of one of said fixtures received in the aligning through holes in the other of said fixtures, said fixture with said through holes having a base of thickness approximately twice the thickness of said lugs of said other fixture whereby when said lugs are disposed in said through holes, recesses are formed on the base of said fixture opposite said lugs, said struts comprising in each case a member having an attachment end portion having alternately disposed through holes and lugs engageable with the outer sides of the back-to-back horizontally disposed faces of said fixture with the lugs of said struts receivable in said recesses to provide a rigid connecting fixture assembly.

2. The combination as set forth in claim 1 wherein said plurality of holes in said first fixture comprise a plurality of radially disposed holes and wherein the opposed alternating lug and hole arrangement of the other fixture comprises in each case a through hole with a pair of lugs, one on each side thereof.

3. The combination as set forth in claim 1 wherein the through holes of said two connecting fixtures and said associated strut are all aligned and a common fastener is fixed through said aligned holes.

4. The combination as set forth in claim 2 wherein the angularly disposed faces of said fixtures comprise in each case an array comprising a through hole and a pair of lugs at either side of said hole, said associated struts in a like manner to the first mentioned struts having a centrally disposed through hole and a pair of lugs engageable with said hole and lugs of said array.

5. A connecting fixture assembly for use in a space frame system comprising at least one space frame, said frame comprising a plurality of elongated stress and load distributing struts interconnected by stress and load distributing fixtures to define upper and lower grid-like chord frame structures disposed in spaced parallel planes; a plurality of elongated stress and load transmitting struts, each connected respectively with fixtures of the upper and lower chord frame structures to define a web structure intermediate said chord frame structures", means for fastening said struts to said fixtures, said fixtures connected in assemblies comprising a pair of back-to-back plates, each having a plurality of flat horizontally disposed faces symmetrically formed thereon relative to the other, said plates further having oppositely disposed angularly directed faces adapted to be connected to struts of said web structure, the

aligned horizontal faces of said plates having a plurality of holes adapted to be connected to struts of said chord frame structure, wherein the improvement comprises a plurality of through holes formed in a radial pattern in each of said flat faces of one of said plates, a plurality of lugs and corresponding coined recessed portions formed in a like pattern in the other of said plates, said lugs having a height substantially less than the thickness of said first plate, whereby when said plates are mounted back-to-back said lugs of said second mentioned plate are received in said through holes of said other plate and a like pattern of holes and recessed portions is provided in the outer surfaces of both said plates, said struts having an arrangement of lugs fitting in said recessed portions and holes aligned with the holes in said plates.

6. The combination as set forth in claim wherein said mating pattern in each of said plates includes at least one through hole, and a fastener is fixed through said through hole to hold said plates and the associated struts in tightly assembled relationship.

7. In a space frame system including a space framework, said framework comprising a plurality of elongated stress and load transmitting struts interconnected by stress and load distributing fixtures to define upper and lower grid-like chord frame structures disposed in spaced parallel planes; a plurality of elongated stress and load transmitting struts each connected respectively with fixtures of the upper and lower chord frame structures to define a web structure intermediate said chord frame structures; and means for fastening said struts to said fixtures; said fixtures including in each case an upper and a lower plate; each of said plates having a like plurality of spaced horizontally disposed attachment faces, each of said plates further having a like plurality of angularly disposed attachment faces, said horizontally disposed face portions being assembled in tight back-to-back relationship; the first of said plates including a pattern of a plurality of radially disposed through holes in each of its horizontally disposed attachment faces, the second of said plates including a like pattern of opposed lugs and through holes, said other plate being substantially twice the thickness of said lugs whereby said lugs extend part way into the opposed through holes of said other plate and form recessed portions on the opposite side thereof, recessed portions being formed in said second of said plates on the side thereof opposite said lugs, said struts including in each case an attachment end portion, said end portion including a pair of raised lugs aligned with and receivable by said recessed portions, and central fastener hole aligned with a like plurality of holes in the horizontally disposed faces of one of the aforesaid plates.

8. The combination as set forth in claim 7 wherein said angularly and horizontally disposed attachment faces are rigidly connected each to the other through connecting gusset portions of said plates.

9. The combination as set forth in claim 7 wherein each of said struts comprises a channel member having a closed flat surface and an open side, said struts further having a like arrangement of lugs and holes located on its closed flat surface.

10. The combination as set forth in claim 7 wherein said struts, and both of said plates, are assembled and held together through an intermediate bolt and nut fastener mounted through said aligned holes.

11. In a space frame system including a space framework, said framework comprising a plurality of elongated stress and load transmitting struts interconnected by stress and load distributing fixtures to define upper and lower grid-like chord frame structures disposed in spaced parallel planes; a plurality of elongated stress and load transmitting struts each connected respectively with appropriate fixtures of the upper and lower chord frame structures to define an intermediate web structure, and means for fastening said struts to said fixtures; said fixtures connected in a connecting fixture assembly including an upper and a lower base plate in back-to-back relationship, each of said base plates further having a pair of upstanding plates mounted thereon and at right angles to the other on its outer surface; each of said vertical plates having an arrangement of openings and lugs for engagement with an associated web strut; the first of said base plates having a pattern of a plurality of radially disposed through holes; the second of said base plates including a like pattern of opposed lugs and through holes, each of said lugs including a coined opening behind it, said first of said base plates being substantially twice the thickness of said lugs whereby said lugs extend only part way into the opposed through holes of said first base plate and leave an opening therein, said chord struts including in each case an attachment end portion, said end portion including a complementary pattern of lugs and holes engageable with a like plurality of said openings in the horizontally disposed surfaces of said base plates.

12. The combination as set forth in claim 11 wherein each of said struts comprises a channel member having a closed flat portion and an open side portion, said struts further having said pattern of said lugs and holes located on its closed flat portion.

13. The combination as set forth in claim 11 wherein said struts, and both of said base plates are assembled and fastened together through an intermediate bolt and nut fastener mounted through their corresponding aligned holes.

14. The combination as set forth in claim 8 wherein a separate reinforcing bar having a plurality of bolt holes formed in it complementary to those of said struts and base plates is attached across said struts and said plates to further rigidify the resultant connecting fixture assembly.

15. The combination as set forth in claim 11 wherein said vertical plates and said base plates in each of said connecting fixtures of said assembly are fastened by welding one to the other.

16. The combination as set forth in claim 15 wherein said vertical plates and said base plate in each of said has fixed on its vertical surface a pattern of outstanding lugs and holes corresponding and complementary to a lug and hole pattern formed on the attachment end portion of each of said web struts.

Claims

1. A space frame sysTem framework comprising a plurality of elongated stress and load transmitting struts interconnected by stress and load distributing fixtures to define upper and lower grid like chord frame structures disposed in spaced parallel planes; a plurality of elongated stress and load transmitting struts, each connected respectively with the fixtures of the upper and lower chord frame structures; means for fastening said struts to said fixtures, said frame work further comprising a double deck arrangement of said chord frames wherein there is an uppermost and a lowermost chord frame and a common intermediate chord frame between the two, said fixtures in said intermediate chord frame comprising an upper and a lower connecting fixture, each having alternate angularly and horizontally disposed strut attachment faces, each of said horizontally disposed faces in one of said fixtures having a plurality of through holes radially thereon, said other fixture plate having on each of its horizontally disposed faces an alternating arrangement of lugs and holes in opposed relationship with said through holes of the other fixture, with the lugs of one of said fixtures received in the aligning through holes in the other of said fixtures, said fixture with said through holes having a base of thickness approximately twice the thickness of said lugs of said other fixture whereby when said lugs are disposed in said through holes, recesses are formed on the base of said fixture opposite said lugs, said struts comprising in each case a member having an attachment end portion having alternately disposed through holes and lugs engageable with the outer sides of the back-to-back horizontally disposed faces of said fixture with the lugs of said struts receivable in said recesses to provide a rigid connecting fixture assembly.

5. A connecting fixture assembly for use in a space frame system comprising at least one space frame, said frame comprising a plurality of elongated stress and load distributing struts interconnected by stress and load distributing fixtures to define upper and lower grid-like chord frame structures disposed in spaced parallel planes; a plurality of elongated stress and load transmitting struts, each connected respectively with fixtures of the upper and lower chord frame structures to define a web structure intermediate said chord frame structures; means for fastening said struts to said fixtures, said fixtures connected in assemblies comprising a pair of back-to-back plates, each having a plurality of flat horizontally disposed faces symmetrically formed thereon relative to the other, said plates further having oppositely disposed angularly directed faces adapted to be connected to struts of said web structure, the aligned horizontal faces of said plates having a plurality of holes adapted to be connected to struts of said chord frame structure, wherein the improvement comprises a plurality of through holes formed in a radial pattern in each of said flat faces of one of said plates, a plurality of lugs and corresponding coined recessed portions formed in a like pattern in the other of saiD plates, said lugs having a height substantially less than the thickness of said first plate, whereby when said plates are mounted back-to-back said lugs of said second mentioned plate are received in said through holes of said other plate and a like pattern of holes and recessed portions is provided in the outer surfaces of both said plates, said struts having an arrangement of lugs fitting in said recessed portions and holes aligned with the holes in said plates.

6. The combination as set forth in claim 5 wherein said mating pattern in each of said plates includes at least one through hole, and a fastener is fixed through said through hole to hold said plates and the associated struts in tightly assembled relationship.

16. The combination as set forth in claim 15 wherein said vertical plates and said base plate in each of said connecting fixtures of said assembly are further accurately aligned and interconnected by a tongue and groove arrangement of mating tabs and recesses.

17. The combination as set forth in claim 16 wherein said vertical plates of each of said connecting fixtures has fixed on its vertical surface a pattern of outstanding lugs and holes corresponding and complementary to a lug and hole pattern formed on the attachment end portion of each of said web struts.