US2420112A

US2420112A - Method of making gratings having interlocked bars

Info

Publication number: US2420112A
Application number: US417501A
Authority: US
Inventors: Elmer W Utzler
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-11-01
Filing date: 1941-11-01
Publication date: 1947-05-06
Anticipated expiration: 1964-05-06

Description

E. w. UTZLER 2,420,112

METHOD OF MAKING GRATINGS HAVING INTERLOCKED BARS May 6, 1947.

Filed Nov. 1, 1941 2 Sheets-Sheet l May 6, 1947. E. w. UTZLER METHOD OF MAKING GRATINGS HAVING INTERLOCKED BARS Filed Nov. 1 1941 J u lv/ a v V m 0/ 9 m M/ I a A I M 9. d f u Z t u T. u

. 9 q f m u n L M 2 INVENTOR Patented May 6, 1947 UNITED STATES PATENT OFFICE METHOD OF MAKING GRATINGS HAVING INTERLOCKED BARS 1 Claim. 1

This invention pertains to steel grating of the type known as pressed steel grating, in which the component parts are assembled under pressure and retained in assembled relation through deflection of the cross members during the application of the aforesaid pressure.

One object of the present invention is to provide a grating of the character described in which the cross bars are deflected during the assembling of the grating and resist separation from the girder bars of the grating by reason of said deflection and frictional engagement of said girder bars and deflected portions of the cross bars.

Another object of the invention is to provide a grating of the character described, in which the cross bars are only partially dependent upon frictional engagement with the girder bars to resist separation therefrom.

Another object of the invention is to provide a grating of the character described, in which the cross bars space the girder bars independently of the engagement between the cross bars and girder bars for the purpose of retaining the said bars in assembled relation.

A further object of the invention is to provide a bearing engagement between the intersecting assembled girder and cross bars which is above the frictionally engaging portions to prevent destruction of the frictional engagement between said intersecting portions of the girder and cross bars during the alternate application and release of loading stresses on said bar or bars.

Steel gratings used as floors of bridges, decks of vessels, platforms of buildings and other structures, as coverings for apertures in various structures and a variety of other uses are well-known in the art. Various means have been used to retain the component parts of the grating in assembled relation, such as friction, rivets, welding and a combination of some or all of these means. Each said means has advantages as Well as disadvantages. Both welding and riveting are objectionable as being the most expensive means. The use of friction as the holding means has been objectionable because loading impacts and vibrations set up in the gratings during their intended use diminish the degree of frictional engagement between the component parts until it is insufiicient to retain the grating members in rigid assembled relation.

The majority of gratings utilizing friction to lock the component members thereof in assembled relation are formed by punching slots or otherwise forming apertures in the load-carrying members and forcing the cross bars down into these slots or apertures under considerable pressure. Many of these gratings, during the intended use thereof, have the cross members pounded into the slots of the load-carrying members which causes Wear of the members at their points of engagement and destroys the holding power of the frictional engagement between the adjacent portions of these intersecting members. Others of the so-called friction-locked gratings distort the cross members during or after application of the assembling pressure thereon as an additional locking means. Here again the cross members being subjected to pounding or vibration are worn or torn at their points of engagement with the load-carrying members, thereby destroying the effectiveness of the holding power of the frictional engagement between the members at the distorted portions. This latter type of grating is also objectionable in that the portions of the members being distorted are of such small crosssection that they are readily torn or worn at their points of engagement with the heavier loadcarrying members or they cut into the loadcarrying members.

Most of th well-known methods of assembling grating utilizing frictional engagement of the girder bars and cross bars to retain the bars in assembled relation perforate or slot one or both intersecting bars in such a manner that the bearing engagement between the intersecting bars is wholly or in major part below the portions of the bars frictionally engaged. It will be obvious that in metal gratings the bars have some degree of elasticity of compressibility under load and when this load is released the bars will return to their normal shape. This alternate application and release of the load upon the grating will cause relative movement between adjacent engaging portions of the intersecting bars which, if continued, breaks the frictional lock between them and causes a wearing away of one or the other of said adjacent engaging surfaces.

In the grating hereinafter described I have utilized the method of slotting the load-carrying members, hereinafter called girder bars, and pressing the cross members, hereinafter called cross bars, into the slots in the girder bars in order to reduce the cost of manufacture. I have eliminated the tendency for tearing, cutting or wearing of the members at their points of contact in the said slots during the intended use of the grating by providing broad bearing surfaces at the intersection of the cross bars and girder bars. I have also eliminated all tendency to destroy the frictional engagement between the intersecting surfaces of the girder and cross bars by placing the bearing surfaces of the intersecting bars above the frictional engaging portions of the intersecting bars. In addition thereto I have so formed each cross bar that it has two oppositely deflected or distorted portions engaging each intersecting cross bar at the place of intersection therewith, thereby materially increasing the holding power of the deflected and frictionally engaged portions.

In the drawings forming part of these specifications, Fig. 1 shows a lan view of a portion of a grating embodying the invention; Fig. 2 shows a section taken on lines 2-2 of Fig. 1; Fig. 3 shows a section taken on lines 33 of Fig. 1; Fig. 4 shows a cross section of the cross bar before assembly with the girder bars; Fig. 5 shows a cross section through the cross bar when assembled with the girder bars; Fig. 6 shows a side elevation of a portion of a cross bar of the form shown in Fig. 4; Fig. 7 is a composite view of a side elevation of a girder bar and three steps in the assembly of the cross bars therewith; Fig. 8 shows one view of a locking means for securing the grating in position during the intended use thereof; Figs. 9 and 10 show side elevations at opposite sides of the locking means of Fig. 8.

In the drawings forming part of the specifications wherein like reference characters are used to refer to like parts; the girder bars indicated by reference character I are the load-carrying members and the cross bars '2 serve principally to lock the girder bars in assembled relation, to brace the girder bars against forces applied in a direction transversely thereof and to transmit all imposed loads on the cross bars to the girder bars.

Each girder bar I is illustrated as of substantially rectangular cross-section and disposed upon one edge. Obviously the girder bar may be of any other shape suitable for performing the intended function of'a girder bar. These girder barsare of a suitable'size, depending upon the load to be supported and the spacing of the supports therefor. Spaced longitudinally of each girder bar I are inverted V-shaped slots 3 extending inwardly ofthe bar from the top edge thereof and of a suitable size and shape to receive the cross bars and deflect same when pressed into the slots 3. As illustrated in Figs. 3 and 7 of the drawings the slots 3 are of substantially inverted V-shape and of a vertical dimension less than the vertical dimension of the assembled cross bars 2. At the apex of the inverted V-shaped slots 3, each side slot is enlarged a'suitable amount to permit ready 'entrance of the undefiected cross bars as will hereinafter be described. The bottoms of the slots 3in the bars I preferably'terminate above the neutral axis of the bars to avoid weakening of the bars to the extent which would occur were the slots carried down below the neutral axis. The inner' top surfaces 4 of the intersecting sides of the slots 3 are suitably formed to provide a bearing for the cross bars I. These slots 3 in a plurality of girder bars are in transverse align ment. I

'Each cross bar2, when in unassembled position, is of substantially inverted U-shape as shown in Figs. 4 and 7 of the drawings and when inassembled relation with the adjacent girder bars I isof substantially inverted V-shape. Spaced longitudinally of each cross bar 2 and corresponding to the spacing of the girder bars tare a plurality of slots 5 extending inwardly from the free edge of each armof the cross bar and 'of sufiicient width to permit the ready entrance of the girder bars. Each arm of thecross bar 2 is preferably of less thickness than that of thegirder bars and are joined together by an arcuate portion corresponding in size to the surface at the juncture of the slots 3 in thegirder bars I. Each cross bar 2 is of a length sufficient to span a plurality of girder bars I and prefer- 4 ably extends the width of the particular section of grating being formed.

As previously referred to, each cross bar is initially formed of inverted U-shape and is in this form when initially inserted in the inverted v-shaped slots of the girder bar. When each cross bar is first disposed across a plurality of spaced girder bars, the slots 5 in the cross bars 2 engage the girder bars I and permit the lower portions of the cross bar to move downwardly and between the girder bars. This downward movement of the cross bar is arrested by the portions above the slots therein engaging with the slots 3 in the girder bars I. Pressure is then applied to the so-positioned cross bars and of a sufficient amount to force the portions of the cross bars above the slots 5 therein down into the slots 3 of the girder bars. During this downward movement of the cross bar, the inverted V-shaped girder bar slots 3 spread and at the same time distort the cross bars at and between the girder bars into a form corresponding to that of the slots 3 in the girder bars I. This movement continues until the upper inner portions at the juncture of the arms of the cross bars seat on the portions 4 of the girder bars.

When the cross bar 2 has seated on the girder bars 2, as described above, the portions of the arms of the cross bar 2 within the slots 3 of th girder bar may engage the bottom of said latter slots, but need not do so. In fact, if the cross bar portion within the slots are so proportioned as to terminate above the bottoms of the girder bar slots, assembly of the cross and girder bars is greatly facilitated and a full bearing of the juncture of the arms of the cross bars upon the portion 4 of the girder bars between the slots therein is assured. Inasmuch as these cross bars are deflected at or above the portion 4 of the girder bar, when entering the slots 3 of the latter the reverse movement must take place when an attempt is made to remove the cross bar from within the slots of the girder bars. Hence each cross bar is doubly locked in each girder bar and as the bottom of each cross bar is wider than the top of the slot in the girder bar the cross bar can not be removed-or separated from the girder bars without a redistortion of the entire cross bar, which i resisted by the girder bar portions between slots 3.

Since the cross bars 2 have bearings on the girder bars I at the points 4, which bearings are above theportions of the cross bar engaged in the slots of the girder bar, there is substantially nomovement of the cross bar within the girder bar slots t when vertical load isapplied to the cross bars, so that any frictional engagement between the cross 'and girder bars'is not destroyed through movement of those portions of the cross bars withintheslots 3 of the girder bars.

There are numerous occasions where it is'desirable to rigidly secure sections of grating'in place by the use of fastening means which are quickly and readily moved from locked tounlocked position so that the grating s'ectionsmay be quickly and readily removed from position or replaced. One such means is illustrated 'in Figs. 8 to 10 of the drawings. This locking means utilizes a novel and positive connection between the'grating'sections and the supports therefore to readily and quicklysecure or remove a section of grating to or from the supports. 1Referring now to Figs. 8 to 10 of the drawings, reference characters I and 2 respectively in'diate the assembled girder and cross bars of a portion of a section of grating. Disposed beneath the section of grating are suitable supporting members l which may be of any desired form and size arranged in sufficient numbers to provide adequate support for the grating and the loads imposed thereon. These supports 1 have been illustrated as inverted pressed channels. One or more of the members 1 beneath each section of gratings are used to lock the grating section in place, in addition to providing a support therefor. One or more of the hereinafter described locking means may be used in looking the grating section to a member 1.

Each locking means comprises the members 8 and 9 on opposite sides of the member 1 and connected together beneath the member 1 by means of the member 19.

The upper end of member 8 has a jointed connection to a member it which terminates in a hook-shaped portion l2 inserted in the aperture i8 of girder bar 4 beneath the cross bar 2 and between the depending arms thereof. The lower end of member 8 terminates in a jointed connection with one end of the member 10.

The members 9 are preferably arranged in pairs on the opposite side of member 1. The members 9 are preferably joined together at their upper ends and have a jointed connection to a member 14 which terminates in a hook portion 55 inserted in the aperture 16 in girder bar I beneath cross bar 2 and between the depending arms thereof. The lower ends of each member 9 terminates in an apertured portion ll depending below the lower edge of member 1. Disposed between these portions ll of members 9 is a locking member i8 and connected with said members 9 by means of pin l9 inserted thru the apertured portions i1 and a suitable aperture in member I8. This pin 19 has a head 29 at one end thereof and an aperture in the opposite end thru which a cotter pin 2! or other suitable fastening means is inserted to retain the pin [9 in position.

Connecting the members 8 and 9 on opposite sides of the member I is a member if! disposed beneath member I. This member ID is preferably a fiat substantially rectangular member, one end of which is hinged to member 8 and the opposite end of which is bifurcated at 22 so that when the member 19 is disposed against member 1 the members 9 will lie within the bifurcation 22 of member 10. This bifurcated portion of member in also provides a bearing for the looking member 18 as will now be explained.

The locking member [8 is preferably a relatively long thin member having a handle shaped. portion l8 at one end and a, cam shaped head portion I8 at the opposite end. This head portion 18* is apertured and mounted on pin [9. The member l9 when mounted on pin I9 is disposed in a direction transversely of the assembled member 19 and the cam shaped head l8 is so formed that the portion I8 thereof will pass beneath member ID to permit assembly and disassembly of the lockin means. The portion I8 of member 18 has a cam shaped surface extending from portion 18 to l8 thereof so as to produce a progressively increasing bearing upon member I as the member I8 is rotated.

The operation of the locking means is as follows. The member 19 is permanently assembled on member 8 and the end I0 of member 8 is assembled in aperture l3 of girder bar I beneath cross bar 2 The members 9 are permanently assembled with member 5 which is engaged in aperture 16 of girder bar i beneath cross bar 2 These members 8 and. 9 are preferably permanently attached to girder bar I on opposite sides of the member 1. The members 9 and assembled locking member 13 are moved laterally away from member I and member 19 is moved across member I so that its bifurcated portion projects beyond the side of member 1 as shown in Fig. 8.

The member 9 with member l8 depending therefrom are moved within the bifurcation 22 of member ID and member I8 is disposed beneath member l0. Member i8 is then rotated until portion [8 thereof engages the under side of member I9 and upon a further slight rotation looks the grating to member 1. The portion I8 is of sufiicient size to take up slight variations in the members 1, i9 and 9 so that a tight bearing of girder bars 1 on top of member 1 and of member [0 upon the underside of member 1 is always obtained.

In the foregoing description and drawings the details of construction of the locking means are more or less conventional in form and many variations in details of construction will suggest themselves to those skilled in the art which may be used without departing from the principle of operation of my invention. Likewise variations in the details of construction and form of the cross and girder bars will suggest themselves to those skilled in the art and it is to be understood that I do not wish to limit myself to the exact form of the invention illustrated except as made necessary by the scope of the appended claim.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

The method of making a grating which comprises providing girder bars in spaced relation, each girder bar having spaced inverted substantially V-shaped slots extending inwardly from one longitudinal edge thereof so that the intersection of the slots provide a cross bar bearing portion below the plane of said longitudinal edge of the girder bar, providing cross bars of inverted substantially U-shape, and assembling the grating by forcing the free ends of the cross bar arms into the girder bar slots and locking the cross bars therein thru progressive deformation until the rounded portion of the cross bar engages the bearing provided therefore on the girder bar.

ELMER W. UTZLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,612,236 Thomson Dec. 28, 1926 1,734,660 Williams et a1 Nov. 5, 1929 2,014,451 Pfeifer, Jr Sept. 1'7, 1935 2,162,497 Barrett June 13, 1939 455,717 Howard et al. July '7, 1891 1,301,981 Smith Apr. 29, 1919 1,348,360 Howell Aug. 3, 1920 1,789,280 Armstrong Jan. 13, 1931 940,083 Stimpson Nov. 16, 1909 886,515 Jude May 5, 1908 1,016,584 Shepherd et a1 Feb. 6, 1912 1,631,691 Nagin June 7, 1927 FOREIGN PATENTS Number Country Date 2,029 British 1910