US3570204A - Truss joists - Google Patents

Abstract

A TRUSS JOIST 20 INCLUDES COMPRESSION WEBS 33 HEAVIER THAN TENSION WEBS 32 AND DOUBLED IN THE HIGHER LOADED PORTIONS. JOINTS 36 INCLUDE KNURLED PINS KEYED TO THE WEBS AND ROTATABLE IN THE CHORDS. HEEL JOINTS 24 INCLUDE ANGLE MEMBERS EXTENDING BEYOND THE PIN 44 OVER THE BEARING WALL 22 AND ANCHORED BY NAILS 84 TO THE UPPER CHORD AND BY NAILS 86 TO THE BEARING WALL. A HIGH LOAD TRUSS JOIST 100 INCLUDES TWO BOARDS FOR EACH CHORD WITH CUPPED SPRING WASHERS 160 RETAINING THE BOARDS ON PINS 134. HEEL JOINTS 114 INCLUDE VERTICALLY SPACING ANGLE MEMBERS SECURED TO THE BEARING WALL.

Description

March 16, 1971 a. R. BIRKEMIER TRUSS JOISTS 2 Sheets-Sheet 1 Original Filed July 22, 1968 qm I w wdl om mmwmlk v GEORGE R. B/R/(EME/El? IN VE /V 7' 0/? BUG/(HORN, BLORE, KLAROU/ST a SPAR/(MAN ATTORNEYS Unitedstates Patent TRUSS JOISTS George R. Birkemeier, Portland, 0reg., assignor to Timber Structures, Inc., Portland, Oreg.

Continuation of application Ser. No. 749,253, July 22,

1968. This application Sept. 24, 1969, Ser. No. 860,841

Int. Cl. E04c 3/292 US. Cl. 52289 14 Claims ABSTRACT OF THE DISCLOSURE A truss joist 20 includes compression webs 33 heavier than tension webs 32 and doubled in the higher loaded portions. Joints 36 include knurled pins keyed to the webs and rotatable in the chords. Heel joints 24 include angle members extending beyond the pin 44 over the bearing wall 22 and anchored by nails 84 to the upper chord and by nails 86 to the bearing wall. A high load truss joist 100 includes two boards for each chord with cupped spring Washers 160 retaining the boards on pins 134. Heel joints 114 include vertically spacing angle members secured to the bearing wall.

This application is a continuation of application Ser. No. 749,253 filed July 22, 1958, now abandoned.

This invention relates to improved truss joists, and more particularly to improved composite wood-steel truss joists.

Truss joists of the type having wooden chords and metal webs known hitherto have had some serious defects. One has been that some of their heel joint constructions have necessitated notching supporting plates on the walls. Variations of the positions of the inside face of each wall required the notches to be of different depths, or all of maximum depth, in order to provide clearance for the webs of the joists. It would be desirable to provide a truss joist structure having a heel joint eliminating the need for notching the supporting plates. Another problem of the prior art truss joists has been that the webs have been expensive and not of a type permitting doubling up of the webbing where required. It would be desirable to provide inexpensive webs which can be doubled to accommodate higher loads. Another problem of prior art truss joists has been that flanges of the heel joints thereof project out beyond the sides of the chords and tend to catch on objects and bend in the handling thereof. Also, in some types of prior art truss joists, too loose a fit is made between the webs and pins connecting the webs to the chords which permits inelastic deformation and poor tolerance characteristics. It would be desirable to provide a truss joist in which there is no inelastic deformation between the webs and the pins connecting the webs to the chords. Another defect overcome by the present invention is that of end distances of webs being too short.

An object of the invention is to provide new'and improved truss joists.

Another object of the invention is to provide new and improved composite wood-steel truss joists.

A further object of the invention is to provide a truss joist having a flush heel joint which is adjustable relative to a wall plate without notching the wall plate and which does not have flanges extending beyond the sides of the chords.

Another object of the invention is to provide a truss joist having a cantilever type heel joint which obviates notching the wall plate supporting the heel joint.

A still further object of the invention is to provide inexpensive, high strength webs for a truss joist.

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Another object of the invention is to provide a truss joist having webs which nest in one another to permit doubling of the webs for high load portions of the joist.

Yet another object of the invention is to provide truss joists having joints between the webs and chords which have no inelastic deformation.

' Another object of the invention is to provide simple, inexpensive, quickly assembled joints between Webs and chords of truss joists.

A further object of the invention is to provide truss joists having long end distances of webs thereof.

The invention provides new and improved truss joists of the composite, wood-steel type including joints between webs and chords thereof in which connecting pins have drive fits with the webs so that there is no inelastic deformation therebetween and very close tolerances are provided. In a truss joist forming one specific embodiment of the invention, an upper wooden chord and a lower wooden chord are provided with centrally located kerf slots extending completely therethrough into which extend flat end portions of steel webs having angular central portions. Pins having longitudinally knurled collar portions are driven through crossbores in the chords and bores in the end portions of the webs with the knurled collar portions cutting their way through the bores in the webs to provide interference fits therebetween, and a heel joint at one end portion of the upper chord has a pair of flanged plates having vertical flanges in a slot in the end portion of the upper chord and connected by a pin to the chord, the end portion of the upper chord resting directly on the wall of a building structure and horizontal flanges of the flanged plates resting on the top of the upper chord.

In a truss joist forming an alternate embodiment of the invention, an upper chord is formed of two parallel wood members on edge and the lower chord is similarly formed, and the webs, both tension and compression, are steel plates formed into angles except for flat end portions. The tension webs and the compression webs are joined together and to the chords by pins preferably having annularly knurled end portions and spring Washers locked on the end portions. The webs are adapted to nest in each other and are used singly in the central portion of the joist where loads are lighter than on the portions nearer the ends of the joist and, in the latter, to accommodate the higher loads, a pair of webs nested in each other are used for a single compression webbing, the fiat end portions of the pair of webs of a compression webbing bracketing the flat end portion of the adjacent tension web to balance the load on the connecting pin of the joint. Heel joints include pairs of angle members having vertical flanges whose upper portions are positioned between the wood members and connected to the wood members of the upper chord and the end tension webs by a pin. Horizontal base flanges of the angle members rest on and are secured to a plate of the wall.

A complete understanding of the invention may be obtained from the following detailed description of truss joists forming specific embodiments thereof, when read in conjunction with the appended drawings, in which:

FIG. 1 is a side elevation view of a truss joist forming one embodiment of the invention;

FIG. 2 is a top plan view of the truss joist of FIG. 1;

FIG. 3 is an enlarged, vertical, sectional view taken along line 33 of FIG. 2;

FIG. 4 is an enlarged, vertical, along line 44 of FIG. 3;

FIG. 5 is an enlarged, vertical, along line 5-5 of FIG. 1;

FIG. 6 is an enlarged, vertical, along line 66 of FIG. 5;

sectional view taken sectional view taken sectional view taken FIG. 7 is an enlarged, perspective view of a connecting pin of the truss joist of FIG. 1;

FIG. 8 is a side elevation view of a truss joist forming an alternate embodiment of the invention;

FIG. 9 is an enlarged elevation view taken along line 9-9 of FIG. 8;

FIG. 10 is an enlarged, vertical section taken along line 10-10 of FIG. 1;

FIG. 11 is an enlarged view of webbing of the truss joist of FIG. 8;

\FIG. 12 is an enlarged, sectional view taken substantially along line 1212 of FIG. 11;

FIG. 13 is an enlarged, vertical, sectional view taken along line 1313 of FIG. 10; and

'FIG. 14 is an enlarged, vertical, sectional view taken along line 114-14 of FIG. 8.

EMBODIMENT OF FIGS 1 TO 7 Referring now in detail to the drawings, a truss joist (FIG. 1) spanning the distance between and supported by walls 22 by heel joints 24, provides clearance so as to fit on the walls regardless of tolerance variations in the spacing between the two walls 22. The heel joints are adapted to provide either a cantilever support as in the illustrated embodiment or to have the joints directly centered over notched plates (not shown) on the tops of the walls, the notches in the plates being provided for clearance of end tension webs 26. The truss joist includes an upper chord 2'8 and a lower cord connected together by the end tension Webs 26 of steel, intermediate steel tension webs 32 and steel compression webs 33, 34 and 35, the heel joints 24 and joints 36 and 38. The chords 28 and 30 may be wood 2" X 4"s to which the webs are connected at joints 38 by pins 44. The tension webs, while in some conditions as, for example, in a Windstorm which tends to lift the roof, have compression loads, need be lighter or less strong in compression than the compression webs and are narrower than the compression webs. The loads on the several webs increase progressively proceeding from the two center webs outwardly to the heel joints 24. To accommodate the higher loading in long joists, two nested web members may be used for each outer Web needing greater strength than a single web member while each web near the center of the joist is a single web. In the joist 20 being described, extra strength over a single web member for each outer tension web is not needed and each of the tension webs is a single web member. For a joist designed to have a higher load than that of the joist 20, the tension webs 26 and 32' can be doubled. The outer compression webs 33 each is two web members, two web members, like the web members 34 and 35, being nested together with flat end portions bracketing flat end portions 42 of the tension webs at the joints 36 and 38 to provide symmetrical or concentric loading on connecting pins 44 of the joints and the adjacent portions of the chords 28 and 30. Also, to provide high strength for compression loads, each compression web 33, 34 and 35 is of the same thickness but is wider than each of the tension webs 26 and 32. For normal length joists or joists with light loads, the webs may all be single rather than double as are the webs 33.-

The webs 26 and 32 to 35 are formed from flat strip stock with central angle portions and 52 formed into the angles to siffen or make the webs strong or column like in compression except for the short end portions 40 and 42 which are left flat with holes 54 punched therefrom. Ribs (not shown) or other stiffening may be provided at the portions of the end portions 40 and 42 between the chords and the angle portions 50 and 52. The angle portions laterally extend equidistantly beyond the two faces of the end portions of the webs. The angle portions extend substantially to the portions of the flat end portions which are supported by the chords.

At the joints 36 and 38, which are the same but inverted, between the chords 28 and 30 and the webs, the

end portions 40 and 42 of the webs fit closely in slots or kerfs 60 in the chords. The slots 60 extend completely through the chords to provide clearance for the long end distances of the webs. The pins 44 are precisely machined, and have chamfered ends 62 to facilitate driving and have enlarged, knurled keying portions or ribs 64 which cut into material around the holes 54, as the pins 44 are driven through the holes 54, and key the pins rigidly to the webs. The keying portions form interference fits with the end portions 40 and 42 and hold the pins against longitudinal movement as well as against rotary movement relative to the holes 54. The pins fit snugly in crossbores 66 in the chords.

Each heel joint 24 (FIGS. 3 and 4) includes a pair of angle members having top flanges 82 resting on and nailed to the top of the upper chord 28 by nails 84 and also are nailed to the wall 22 by long nails 86. Vertical flanges 88 fit into an end slot 90 in the upper chord and have aligned holes receiving one of the pins 44 with interference fits. The two flanges 88 are on opposite sides of the web 26. The heel joint permits the chord 28 to' rest directly on the wall with the pin 44 and the web 26 spaced inwardly slightly from the inner face of the wall so that the wall need not be notched to provide clearance for the web. The load from the web 26 is transferred to the pin 44. The vertical component of the load is transferred from the pin 44 to the angle members 80 and the horizontal component of the load is transferred by the pin to the chord 28.. The vertical component of the load is transferred by the top flanges 82 of the angle members, which extend over the wall 22, vertically to the portion of the chord 28 thereunder, and from this portion of the chord to the wall 28, this vertical component of the load being perpendicular to the direction of the grain in the wand chord.

EMBODIMENT OF FIGS. 8 TO 14 For very high loads, truss joists are used. Each truss joist 100 includes an upper chord 102 connected by joints 106 and 107 and webs 108 and 110 to a lower chord 112. Heel joints 114 including angle members 115 mount the truss joists on walls 116. The webs 108 and 110 are similar to the webs 26 and 32 to 34 and the joints 106 are similar to the joints 24 except for pinning to the pairs of chord members 122 which make up the chords 102 and 112 and which may be 2" x 4". Bridges 124 and cross braces 126 tie the adjacent trusses 100 together.

Each heel joint 114 includes the angle members 115, each having a base 131 and a vertical portion 132 connected by a pin 134 to the web 108 and to the chord member 102. The pin 134 can be positioned directly over the Wall 116, the vertical portions 132 spacing the pin 134 sufficiently above the top of the wall to provide clearance for the web 108. The joint 114 also may be positioned offset slightly from the top of the wall and be supported by ap late (not shown). Nails or other fastening members secure the angle members 115 to the wall.

As illustrated best in FIGS. 11 and 12, the webs 110 nearer the ends of the truss joist bear higher loads and are doubled up, the two Webs making up each Webbing being nested with flat end portions of the webs 108 being centered between two flat end portions 152 of the webs 110. The pins 134 may be solid or tubular and may be smooth or may have raised longitudinal knurled keying portions or ridges 154 cutting keyways through the webs to form interference fits with the webs and fitting snugly in crossbores 156. Outer end portions of the pins have annular threads or knurls 158 and cuppel spring washers 160 are snapped onto these end portions and are firmly locked on the pins. The annular threads or knurls may be omitted if less holding force is needed.

What is claimed is:

1. In combination:

a supporting member having a top of a predetermined width and an inner face,

wood chord members including a top chord member having an end portion resting on the top of the supporting member,

web members connecting the chord members including an end web member,

load transferring angular plate means having an elongated top portion bearing on the top of the end portion of the top chord member and extending over the supporting member and also having a vertical portion extending downwardly from the top portion,

and pin means extending through one end portion of the end web member and the vertical portion of the plate means and at least partially through the top chord member,

the pin means being spaced substantially from the adjacent end of the top chord member and connecting the end web member to the top chord member and the plate means to transfer load from the end web member along the plate means toward the adjacent end of the chord member and through the plate means and the top chord member to the top of the supporting member,

the pin means being positioned sufliciently inwardly from the inner face of the supporting member to space the upper end portion of the end chord member inwardly from the inner face of the support member,

the top portion of the angular plate means extending from the pin means substantially to the adjacent end of the top chord member and across substantially the entire width of the supporting member to transfer load from the pin means to the supporting member through the upper chord member.

2. The combination of claim 1 wherein the angular plate means comprises a rigid angle having a top flange abutting the top face of the top chord member and a vertical flange abutting the top chord member.

3. The combination of claim 1 wherein the end portion of the top chord member has a longitudinally extending slot therein extending to the end of the top chord member, and the angular plate means comprises a pair of angle members having vertical flanges positioned in the slot and having aligned holes therein fitting closely on the pin means and also being provided with top flanges resting on the top of the end portion of the upper chord member and extending substantially to the end of the top chord member.

4. The combination of claim 1 wherein the pin means and said one end portion of the end web are positioned beyond the supporting member and the angle members extend over at least the major portion of the width of the supporting member.

5. In a truss joist:

a wood chord member having a slotitherein and a crossbore intersecting the slot,

a pair of metal webs having end portions positioned in the slot and having holes therethrough aligned with the crossbore,

and pin means extending through the crossbore and the holes,

the pin means comprising a pin having a central portion provided with raised portions and smooth cylindrical portions at each side of the central portion, the raised portions effectively engaging only the end portions of the webs and preventing longitudinal movement of the pin through the holes from normal forces on the pin.

6. The truss joist of claim 5 wherein the raised portions comprise keying ribs extending along the pin and through the holes and cutting into the portions of the webs around the holes.

7. The truss joist of claim 5 wherein the raised portions comprise keying ribs extending through the webs and having an interference fit therewith.

8. The truss joist of claim 5 wherein the slot extends completely through the chord and the end portions of the webs extend substantially completely through the slot.

9. In combination:

a bearing wall having a top and an inner face,

an upper chord having an end portion extending substantially completely across the top of a bearing wall and having a longitudinal slot extending substantially from the adjacent end of the chord to a point spaced substantially inwardly from the bearing wall, the upper chord also having a transverse horizontal bore therethrough positioned inwardly from the inner face of the bearing wall and intersecting the slot, a web having an end portion extending into the slot and provided with a hole aligned with the bore in the chord, a EOilZOnlfil pin extending through the bore and the o e, and load-transferring elongated sheet metal support means having a first portion extending into the slot and engaging the underside of the pin and also having a second portion engaging the top face of the upper chord and extending along substantially the entire length of said top face of the adjacent end portion of ltlhe upper chord and extending over said bearing wa 10. The combination of claim 9 wherein the sheet metal support means comprises a pair of angle members having vertical flanges extending into the slot and provided with bores receiving the pin and also having horizontal flanges engaging said one horizontal face of the upper chord.

11. The combination of claim 10 wherein the hori Zontal flanges rest on the upper face of the upper chord and have holes over the walls for nails to secure the joist to the wall.

12. The combination of claim 9 wherein the second portion of the sheet metal support means rests on the upper face of the upper chord.

13. In combination: a supporting wall having a top and an inner face, wood chord members including a top chord member having an end portion resting on the top of the supporting wall and having a vertical slot therein,

web members connecting the chord members including an end web member having an end portion extending into the slot,

load-transferring angular plate means having an elongated top portion bearing on the top of the end port on of the top chord member and also having a ver- U031 portion extending downwardly from the top portion into the slot,

and pin means extending through said end portion of the end web member and the vertical portion of the plate means and at least partially through the end portion of the top chord member,

the pin means being spaced substantially from the adacent end of the top chord member and connecting the end web member to the top chord member and the plate means to transfer load from the end web' member through the plate means and the top chord member to the top of the wall,

the pin means being positioned at least partially inwardly from the inner face of the wall to space the end web member inwardly from the inner face of the wall,

the elongated top portion of the angular plate means extending from the pin means substantially to the adjacent end of the top chord member and substantially entirely across the wall to transfer load from the pin means to the wall through the end portion of the top chord member.

14. In a truss joist:

an upper chord,

a lower chord,

a plurality of tension webs secured to the chords in positions in which the webs are tensioned when the chords are placed under load,

a plurality of compression webs of which some are located near the center of the joists and others are located near the ends of the joists and in positions in which the compression webs are compressed when the chords are placed under load,

each of the compression webs including at least one web having plate-like end portions and an angular central portion,

each compression Web located near the ends of the joists comprising a nested pair of the webs,

and pins connecting the webs to the chords and forming joints therewith,

the end portions of each nested pair of webs at each joint being positioned concentrically relative to the end portion of the Web forming the joint therewith, the end portions of each nested pair of webs are positioned on opposite sides of the end portion of the 8 tensioning web forming the joint therewith to make the loading at the joint concentric.

References Cited 5 UNITED STATES PATENTS 1,693,660 12/1928 Obbard 52-693 3,333,874 8/1967 Gelfarb 287-2092 3,330,087 7/1967 Troutner 50-693 3,059,293 10/1962 Eddleblute 52-639 10 3,426,498 2/1969 Ezell 52-695 FOREIGN PATENTS 1,373,404 8/1964 France 52-693 15 1,028,902 1966 Great Britain 5'2-693 JOHN E. MURTAGH, Primary Examiner US. 01. X.R.

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