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Publication numberUS3469359 A
Publication typeGrant
Publication dateSep 30, 1969
Filing dateJul 13, 1965
Priority dateJul 13, 1965
Publication numberUS 3469359 A, US 3469359A, US-A-3469359, US3469359 A, US3469359A
InventorsNagin Leon
Original AssigneeReliance Steel Products Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Friction locked grating and other open grid structures
US 3469359 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Sept. 30, 1969 L. NAGIN- 3,469,359

FRICTION LOCKED GRATING AND OTHER OPEN GRID STRUCTURES Filed July 15, 1965 2 Sheets-Sheet l L n v 1 n n r n n n 3 L n 1| n I u n u L I u n n u u u I u u MA u 11 n u u u u ll ll [I II ll H A II I] u u' n 1] I -n u 11 j Fig.1 2b 2c 20 2b r H r 2c K2 I I I 2 2 I l W |H% E d 2a I, I 3 91i 2a. Fig.6.

. 2c 2 2 Hi 2c [I Zc Fig.4. 2c 4 4 2 4 4 I I l I I I M Fig.5.


LEON NAGIN pflggjmawu his ATTORNEYS United States Patent US. Cl. 52-177 Claims ABSTRACT OF THE DISCLOSURE The invention is concerned with an open grid or grating whose bearing bars are slotted to slidably receive angularly disposed cross bars embodying an enlarged portion, which cross bars are subsequently rotated to final position and during rotation the said enlarged portions are deformed, locking the cross and bearing bars in assembled relation.

The present invention relates in general to open grid load bearing structures and to lattice type structures as used both for decorative architectural and other purposes wherein rigidity. and self-supporting strength are desirable. Such structures may be of ferrous and non-ferrous metals. Non-ferrous metal structures of the type herein described are generally lighter in weight than those of equal strength made of ferrous metals.

I Many attempts have previously been made to produce a friction locked grating which will remain in tight assembly under trafiic conditions. Much difficulty hase been encountered in attaining this result since the cross bars, under alternate application of load and release therefrom tend to cut into their supporting surfaces on the bearing bars and in moving relative thereto impair the initial friction lock.

Previous attempts to overcome this condition as by welding the bearing and cross bars together have not always been successful, particularly in light-weight grating. The welding of aluminum requires special equipment and is thus more expensive to fabricate and assemble, than are welded ferrous metal grating.

One object of the present invention is to provide novel forms of friction locked open grid load bearing structures and lattice type structures for other purposes which are light in weight and which remain in tight assembly under all conditions of their intended use.

Another object of the invention is to provide an aluminum open grid grating of the type described, wherein each cross bar is locked in frictional engagement to the bearing bars at a plurality of points along the length of each cross bar.

A further object of the invention is to provide a friction locked reversible load bearing grating, embodying the principles of the invention.

These and other objects of the invention will be made apparent from the following specification and the drawing forming a part thereof wherein:

FIG. 1 shows a plan view of a section of grating embodying one form of the invention;

FIG. 2 shows a cross-section taken on lines 22 of FIG. 1, illustrating the friction locked relation between the cross bar and the bearing bar in final assembly;

FIG. 3 shows an enlarged plan view of a portion of the grating of FIG. 1 illustrating a second friction lock between the bearing and cross bars adjacent the top of the bearing bar;

FIG. 4 shows a side elevation of a portion of a bearing bar illustrating the slotted openings therein to receive the cross bars;

3,469,359 Patented Sept. 30, 1969 ice FIG. 5 shows a side elevation of a portion of a cross bar, illustrating the manner of notching the cross bar for rotation thereof into final assembled position;

FIGS. 6 and 7 show end elevations of alternate forms of a cross bar;

FIG. 8 shows in plan view a section of reversible grating embodying an alternate form of my invention;

FIG. 9 shows in side elevation a portion of one form of bearing bar as employed in a reversible grating of the invention and having the web thereof slotted to initially receive the cross-bars;

FIG. 10 shows an end elevation of the bearing bar of FIG. 9;

FIG. 11 shows in side elevation a portion of one form of cross bar to be employed in a reversible grating embodying the invention;

FIG. 12 shows an end elevation of the cross bar of FIG. 11;

FIG. 13 shows a partial side elevation of the bearing bars of FIG. 9, illustrating the manner in which the cross bar is rotated to final position;

FIG. 14 shows a partial side elevation of a bearing bar as in FIG. 9 with an alternate form of slots in the web thereof to receive the cross bar of FIG. 15 and illustrates consecutively a bearing bar slot, the cross bar as initially received in the bearing bar slot and the cross bar rotated to final position;

FIG. 15 shows an end elevation of the cross bar of FIG. 14; and

FIG. 16 shows a partial elevation of the cross bar of FIG. 15 with slots in the cross bar to receive the bearing bar head portion when the cross bar is rotated to upright position.

Referring now in detail to FIGS. 1 to 5 of the drawings, the grating comprises a plurality of longitudinally disposed and transversely spaced bearing bars 1 or load carrying members, connected by cross bars 2. As shown in FIGS. 2 and 3, the bearing bars 1 are preferably of rectangular cross section. Spaced longitudinally of bars 1 and intermediate the vertical marginal edges thereof, as shown in FIG. 3, are a plurality of openings 3 corresponding in shape to the shape of the cross bars 2. The openings 3 of the bearing bars are slightly larger than the cross bars to be received therein. Preferably the cross 'bars 2 are freely received in openings 3 with a minimum clearance. These openings 3 extend in spaced relation longitudinally of the bearing bar 1, preferably alternately disposed, so that the cross bars are initially disposed horizontally for insertion through openings 3 of successive bearing bars and thereafter are rotated as hereinafter discussed.

The cross bars 2 are preferably of a modified rectangular shape having a base portion 2a of greatest width and one side wall 2b sloping inwardly from above the base portion, as shown in FIG. 2. The top and bottom longitudinal edges and one side wall of cross bar 2 are preferably at right angles to each other. The height of the cross bar 2, when in erected position after rotation, brings its edge 26 preferably into the plane of the top edges of bearing bars 1. As best shown in FIG. 5, the cross bar 2 has rectangular slots 4 therein, of the same or slightly less width than that of the thickness of the bearing bars. Such slots 4 extend inwardly from the top edge 20 thereof to said rectangular base portion and are spaced longitudinally of the cross bar for a purpose to be herein dis cussed.

As best shown in FIGS. 2 and 3, the grating is assembled by threading the cross bars 2 horizontally through the aligned bearing bar slots 3. Each cross bar is thus alternately disposed relative to the next succeeding cross bar inwardly of the bearing bar, whereby each cross bar, in rotating to erect position, is rotated in an opposite direction relative to each preceding and succeeding cross bar. By reason of the slots 4 of the cross bars being of equal or less width than the thickness of the unslotted bearing bar portions, the unslotted cross bar portions between adjacent girder bars are deflected slightly during rotation and frictionally engage the adjacent girder bar portions.

During this same substantially 90 rotation of the cross bars relative to the bearing bars, the substantially square thicker base portion of the cross bar rotates within the slightly enlarged correspondingly shaped bearing bar slotted portions. Since such slotted bearing bar portions are only slightly larger than the cross bar base portion, the latter is deformed during this rotation and provides a strong frictional interlocking of the contacting surfaces. To facilitate deformation of one of the contacting surfaces, the cross bars may, but not necessarily, be formed of a softer metal than that forming the bearing bars.

Due to the foregoing rotation of the cross bars 2 relative to the bearing bars 1, the slotted portions 4 of the cross bars are in deflected frictional locking engagement with the adjacent unslotted portions of the bearing bars 1. As a result, portions of each cross bar 2 are locked into frictional engagement with the adjacent slotted and nonslotted areas of the bearing bars 1. Additionally the broad base 2a of the cross bars is in bearing engagement with the slotted portion of the bearer bars resisting penetration of the loaded cross bars into the underlying bearing bar portions.

It will be understood that alternate forms of suitable bearing and cross bars may be employed. It is desirable to have the cross bar base portion of greater cross-sectional area than that of the bearing bar, as hereinbefore stated. Cross sections of two alternate forms of cross bar are shown in FIGS. 6 and 7 of the drawing. It will be understood that in all cases the bearing bar slots will conform, in shape, to the cross bar to be freely received therein.

Referring now to FIGS. 8 to 13 of the drawing, wherein is shown a modification of the invention, the grating hereinafter disclosed is referred to as a reversible grating. That is, either planar face of the grating may be the load receiving surface and the grating may be inverted when desired.

As shown in FIG. 9, the bearing bars 101 are symmetrical about their longitudinal centerline or neutral axis. Such bars '101 may be of any desired contour and may be an extruded or rolled member.

Bearer bars 101, as shown, preferably comprise an aluminum extrusion having thickened top and bottom portions 102 connected by an intermediate web portion 103, of lesser thickness. Such bars, of course, may if desired be of uniform thickness throughout the vertical height thereof. The outer faces 102a of the bars 101 may have suitable corrugations therein, as indicated, to provide a non-skid surface. Spaced longitudinally of bearing bars 101 are suitable apertures or slots 104 to receive cross bars 105. Such slots 104 are slightly larger than the cross bars to be received therein so as to facilitate threading the cross bars 105 therethrough. The cross bars, as shown in FIG. 12, have a thickened intermediate portion and, as indicated by the longitudinal neutral axis x of the bar, this enlarged portion of slot 104 is preferably equally spaced about said neutral axis.

Cross bars 105, as shown in FIGS. 11 and 12, are of a modified T-shape, having an elongated top portion 105a. and a substantially rectangular mid-portion 105b of greater thickness than said top portion 10511. The portion 105a, at opposite ends of mid-portion 105b, is provided with inwardly extending suitably shaped slots 105c therein conforming to the shape of the bearing bar portions to be received therein, as hereinafter discussed. The respective widths of slot portions 105c in the cross bars are preferably that of the corresponding portions of the bearing bar 101 to be engaged thereby.

Referring now to FIGS. 9 and 13, after the bearing bars 101 and cross bars 105 have been slotted, as above described, the cross bars 105 initially disposed in a horizontal position are freely threaded through the corresponding bearing bar slots 104 of FIG. 9. Thereafter each of the cross bars 105 are rotated through an angle of substantially into the position as best shown in FIG. 13. By reason of the cross bar initially conforming to the shape of the slots 104 in the bearing bar and being only slightly smaller than the adjacent bearing bar slot portions, the cross bar portions 10511 must deform during rotation from horizontal to vertical position. To facilitate such deformation, the rolled or extruded aluminum cross bars 105 may, but not necessarily, be made of a softer alloy than that from which the bearing bars are made. During such deformation of cross bar portions 105b, a strong friction locking effect is established at this portion of the intersection of the bearing and cross bars.

The slotted upper and lower portions 105c of the cross bars 105, being substantially of the same dimensions as that of the bearing bar portions to be engaged thereby, may also deflect or distort during the aforesaid rotation. This deflection or distortion would provide a strong frictional locking engagement at the respective areas of contact as the cross bars move into vertical position. As a result thereof each of the cross bars, at each area of engagement with the several bearing bars, effects a strong frictional locking engagement for substantially the full vertical height of the cross bar. If desired, the cross bars, being symmetrical about the mid-portion 105c thereof, may be alternately rotated clockwise or counter-clockwise upwardly from horizontal to vertical position, about such mid-portion 105b as previously described in connection with FIG. 2 of the drawing.

A further modification of the invention is shown in FIGS. 14, 15 and 16 of the drawings. Here the longitudinally extending bearing bars 201 comprise enlarged head portions 202 at opposite longitudinal edges of a web portion 203. Each head portion 202 may have a grooved face 202a similar to that shown at 102a of FIG. 10. Such shaped members are sometimes referred to as I-bars.

The cross bars 205, as shown in FIG. 15, are comprised of a substantially square or rectangular base portion 206 and an upstanding thinner portion 207. Portions 207, above the base portion 206, as shown in FIG. 16, has suitable slots 205a therein to receive the web 203 and one head portion 202 of the bearing bar 201. The base portion 206 of the cross bar at one or more sides thereof may be provided with indentations, such as 208 extending the length thereof. These latter indentations facilitate deformation of portion 206 during movement from initial to final position as illustrated in FIG. 14.

As shown in FIG. 14, the web 203 of the bearing bar 201 is slotted at 204 to freely receive the cross bars 205. Slots 204, instead of being horizontally disposed as at 104 in FIG. 9, are disposed substantially at 45 to the horizontal centerline of each bearing bar 201. Slots 204 are preferably of such size as to permit freely threading the cross bar therethrough, but with a minimum of clearance. For purposes of illustration, FIG. 14, at A shows the slotted opening 204 only, at B is shown slot 204 with a bearing bar 205 mounted therein, and at C is shown slot 204 with the bearing bar 205 rotated to vertical position. As will be noted upon comparison of B and C, the indentations 208 facilitate deformation of the cross bar base portion 206 in moving from position B to final assembled position C.

Having disclosed and described several species of the invention, it will be apparent that the longitudinal or bearing bars may be of a plurality of different shapes, as may also the connecting cross bars. Additionally, the herein described methods of assembly may be employed to provide other forms of assemblies in addition to gratings, such as lattice type structures.

The friction lock between the enlarged portions of the cross bars and the webs of the longitudinal bars is obtainable from a variety of shapes, provided only that one or the other or both are partially distorted during movement relative to each other. Thus the cross bars may be friction locked only at their intersection with the longitudinal bars, or as shown in FIG. 13, a cross bar may have two frictional locking engagements with each longitudinal bar.

When non-ferrous metals are employed in the longitudinal and cross bars, I have found that many suitable alloys may be employed, depending upon the end use of the completed structures. In the case of aluminum, many of the alloys may be employed in both longitudinal and cross bars. If desired, and the conditions of use permit, a softer alloy may be employed in one of the intersecting bars to facilitate assembly.

I claim:

1. In a grating, the combination of,

(a) a plurality of longitudinally disposed transversely spaced rectangularly shaped bearing bars, each having a depth greater than the thickness thereof and each bar provided with a plurality of longitudinally extending spaced slotted openings therethrough for reception of cross bars extending between a plurality of said bearing bars,

(b) each said beairng bar slotted openings being of sufficient dimensions to freely receive the cross bar disposed therethrough and conforming to the contour of said cross bar being initially disposed therein,

(c) a plurality of transversely disposed cross bars spaced longitudinally of said bearing bars within said slotted openings thereof and each comprising a longitudinal disposed angularly shaped intermediate portion of maximum thickness with portions of lesser thickness extending laterally from opposite margins thereof, and

(d) slotted openings in said laterally extending cross bar portions at each side of said cross bar intermediate portion for embracing the upper and lower marginal portions of the bearing bars during rotation of the cross bar mid-portions into frictional locking engagement with said bearing bar slotted openings.

2. The grating as defined in claim 1, wherein said cross bar angularly shaped intermediate portions, when initially mounted in said bearing bar slots, extends above and below the neutral axis of said bearing bars.

3. The grating as defined in claim 1, wherein said hearing bar has its longitudinal marginal portions of greater thickness than the slotted connecting web portion receiving said cross bars.

4. The grating as defined in claim 3 wherein the exposed faces of said bearing bar longitudinal marginal portions are serrated to provide a non-skid surface.

5. In an open grid structure of the character described,

the combination of (a) a plurality of longitudinally disposed and transversely spaced bearing bars each having a depth greater than the thickness thereof and each having a plurality of longitudinally spaced slotted openings therethrough for reception of cross bars extending transversely thereof,

(b) each cross bar opening being of suflicient dimensions to slidably receive a cross bar being threaded therethrough at an angle to the vertical axis of the bearing bar and including a rectangular shaped portion, slidably receiving a correspondingly shaped portion of said cross bar,

(c) a plurality of transversely disposed cross bars each extendable through a plurality of the transversely aligned slots in said longitudinally disposed bars into fully threaded position relative thereto,

(d) each said cross bar having an enlarged portion thereon in spaced relation to at least one longitudinal edge of the 'bar and which corresponds in shape to said bearing bar rectangularly shaped opening and having a plurality of slotted openings therein extending from said longitudinal edge to said enlarged portion and in registry with adjacent areas of the bearing bar when the threaded cross-bar is in said fully threaded position so that each said cross bar may be rotated about its longitudinal axis from said full threaded position to a final position angularly displaced therefrom, and

(e) said cross bar enlarged portion being so dimensioned relative to the corresponding opening in said bearing bar that it will be permanently distorted by the bounds of said opening in the course of such rotation.

References Cited UNITED STATES PATENTS 1,132,021 3/1915 Mark et al. 52667 1,426,736 8/1922 Hess 52-667 2,287,558 6/1942 Nagin 52-667 FOREIGN PATENTS 810,856 1/1937 France. 1,007,873 2/ 1952 France.

FRANK L. ABBOTT, Primary Examiner PRICE C. FAW, JR., Assistant Examiner US. Cl. X.R. 52-667; 669

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1132021 *Jul 1, 1914Mar 16, 1915Mark & Mohl IncGrating.
US1426736 *Feb 10, 1921Aug 22, 1922Hess William HGrating
US2287558 *May 21, 1938Jun 23, 1942Reliance Steel Prod CoGrating structure
FR810856A * Title not available
FR1007873A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3710529 *Jul 13, 1970Jan 16, 1973Pass & Sohn GummiwerkGrate
US3943675 *Mar 11, 1975Mar 16, 1976Otto WyssGrating
US4566243 *Nov 21, 1984Jan 28, 1986Benchcraft, Inc.Plank grating assembly
US4727704 *May 7, 1987Mar 1, 1988Fibergrate CorporationGrating structure and method for assembly
US4903444 *Oct 3, 1988Feb 27, 1990Berndt Jr Fred PFloor grating
US5791102 *Jun 23, 1995Aug 11, 1998Gary SheathCruciform joint of glazing bars
CN103591448A *Oct 18, 2013Feb 19, 2014天长市飞龙金属制品有限公司Cross-penetrating fixed steel lattice plate
CN103591448B *Oct 18, 2013Aug 17, 2016天长市飞龙金属制品有限公司一种交叉穿插固定型钢格板
WO1996000340A1 *Jun 23, 1995Jan 4, 1996Gary SheathA cruciform joint of glazing bars
U.S. Classification52/177, 52/669, 52/667
International ClassificationE04C2/30, E04C2/42
Cooperative ClassificationE04C2/425
European ClassificationE04C2/42A1B