US2269522A - Highway grating - Google Patents

Description

Jan. 4 H. c. DREIBUSS ET AL HIGHWAY GRATING Filed June 17, 1940 THE/l? 147- To mm K5.

Patented Jan. 13, 1942 arse STATES HIGHWAY GRATING Harry C. Dreibuss and Fred H. Spenner, St. Louis, Mo., assignorsto Scullin Steel Co, St. Louis, Mo a corporation of Missouri Application June 17, 1940, Serial No. 340,960

4 Claims.

Our invention relates to gratings, particularly to highway gratings of the type that span drainage or vault openings in the roadway and are submitted to the full brunt of trafiic. The principal objects of the present invention are to devise a highway grating that will be able to withstand the stresses imposed by heavy vehicular traffic, that can be made of cast steel, that will have a maximum strength and a maximum area of inlet openings for the amount of metal embodied therein and whose openings will be selfcleaning.

The invention consists principally in a cast steel grating with continuous sides and ends, and

with cross beams extending from side to side, all

of said beams having their end portions extended below the side members and terminating in the same horizontal plane; it also consists in such a grating wherein the cross members consist of one series, whose bottom straight from the downward enlargement at one end thereof to the downward enlargement at the other end thereof, and a second series alternating with those of the first series and whose depth near their end enlargements is substantially equal to the depth of the cross members of the first series and which increase in depth to a maximum depth midway of their length; it also consists in such a grating wherein there are two members extending longitudinally from end to end with their top substantially flush with the tops of the cross members, the sides and cross members defining openings whose side walls diverge downwardly to make the device selfcleaning; and it also consists in the combina-v tions hereinafter described and claimed.

In the accompanying drawing, which forms part of the specification and wherein like symbols and like reference numerals refer to lik parts wherever they occur:

Fig. 1 is a plan view of a highway grating embodying our invention,

Fig. 2 is an end View of said grating,

Fig. 3 is a cross-sectional View on the line 3-3 in Fig. 1,

Fig. 4 is a longitudinal sectional view on the line 44 in Fig. 1,

Fig. 5 is a fragmentary side elevational view of said grating; and

Fig. 6 is an enlarged fragmentary vertical cross-section, showing our highway grating seated on a bearin plate in a drainage inlet opening.

Our highway grating is cast in a single piece of steel. It is of rectangular outline with conedge is substantially? tinuous straight side members I and two series of cross connecting members 2 and 3 respectively, extending from side member to side member. All of the cross members 2 and 3 are of substantially even height with the side members I. The cross members. 2 of one series are, throughout the greater portion of their length, straight and of substantially even depth with the side members, but their end portions are extended downwardly, as at t, below the plane of the side members I. The cross members .3 of the second series are arranged alternately with the cross members 2 of the first series and have downwardly extending end portions 5 of the same depth and shape as the end portions 4 of the cross members of the first series. Near the end portions 5 of the cross members 3 of the second series, the depth thereof is substantially equal to the depth of the intermediate portion of the cross members 2 of the first series and from these points the depth of the cross-members of the second series increases gradually to the middle portions 6 thereof where the depth is somewhat greater than at the downwardly extending end portions 5 thereof.

Extending lengthwise of the grating from end to end thereof are two longitudinal members I of substantially even depth with the side. members I and the intermediate portions of the shallow cross members 2. There are two of these longitudinal members 1 spaced evenly from each other and from the side members I of the grate. Thus a row of elongated openings 8 of even length are formed between the cross members 2 and 3 and the longitudinal two members 1 and additional rows of openings 9 of the same size are formed along each side of the middle row between said cross members, said longitudinal members and the side members I of the grate. The side members I, cross members 2 and 3 and longitudinal members 'I taper in width from top v to bottom, whereby the openings 8 and 9 have downwardly diverging side and end walls which make said openings self-cleaning,

The width of each opening is. determined with reference to requirements of trafiic and the total area of the openings is determined by reference to rainfall or other drainage consideration or ventilation and the length of the grating will vary with the required total area openings. On the other hand, the strength of the grating, the selfcleaning functionand its economical use of the materials are dependent upon the structural design of the grating and particularly upon functional coordination of the several parts thereof.

Thus all the cross members 2 and 3 function as beams to sustain vertical load. By making the shallow beams of less depth than the deep beams, the vertical depth of the openings between the deep and shallow beams is shortened with consequent decrease of the probability of trapping litter that might be unable to go through an opening of the same width with greater depth; and by extending the end portions of both the shallow and deep beams downwardly below the bottoms of the side members I, the openings 9 between adjacent beams open, as at 9a, through the sides of the grating below said side members.

The longitudinal members I serve to stabilize the cross members 2 and 3 and prevent them from buckling under beam action. The end portions 4 and 5 of the cross or transverse members 2 and 3, respectively, being the portions of increased depth, are intended to rest upon a bearing plate I!) provided therefor in the Wall ll of the inlet opening of the drain or vault system. Thus, there is a concentration of stresses, principally shearing stress, just inwardly of the end bearing portions 4 and 5 of the cross members 2 and 3 and such stresses are relieved by increasing the depth of all said members or beams from points somewhat inwardly of said end portions to the inner ends thereof; that is, by the addition of the fillets l2 and I3 that round or fill out the angles between deep end portions 4 and 5, respectively, of said cross members and the adjacent shallow portions thereof. These fillets function as gussets and are well adapted to stiffen and strengthen the cross or transverse members 2 and 3.

As stated above, the width of the openings in the grating is determined by the requirements of trafiic; but the length of the openings is within the control of the designer, the greater the length consistent with strength and economy, the more eificient it is for self-cleaning. It is for this reason that two longitudinal members I are sufficient to prevent buckling of the cross members 2 and 3 under all reasonable trafiic loads. It is noted that all parts of our grating cooperate directly with one another, the cross members 2 and 3 functioning as composite beams are spaced closely together at the top, for a shallow depth, below which the deeper beams 3 extend but with a wider spacing, while the gusset action of all of the beams near their supports develops greater strength than would otherwise be obtainable, while the longitudinal members prevent buckling of the beams and enable them to develop their efiicient beam strength.

While it is preferable to make the hereinbefore described grating in the form of a one-piece casting, it may be desirable in some instances, to make the grating of separate sections connected together in any desired manner.

What we claim is:

1. A highway drainage grating comprising side members connected by two series of spaced cross members having their tops substantially flush with the tops of said side members and their end portions extended downwardly below the bottoms of said side members, the cross members of one series alternating with those of the other series, the depth of the cross members of one series being substantially uniform between the downwardly extended end portions thereof, the cross members of the other series increasing in depth from their downwardly extended end portions to points midway of their length.

2. A highway drainage grating comprising side members connected by two series of spaced cross members having their tops substantiallyfiushwith the tops of said side members and their end portions extended downwardly below the bottoms of said side members and terminating in substantially the same horizontal plane, the depth of said cross members of one series between their downwardly extended end portions being substantially the same as the depth of said side members, the cross members of the other series increasing in depth from their downwardly extended end portions to a depth at their middle portions greater than the depth of said downwardly extended end portions.

3. A highway drainage grating comprising side members connected by two series of spaced cross members having their tops substantially flush with the tops of said side members, the cross members of both series having their end portions extended downwardly below the bottoms of said side members and terminating in the same horizontal plane, the cross members of one series having a depth intermediate their downwardly extended end portions substantially equal to the depth of said side members, the cross members of the other series alternating with those of the first series and having a depth which, adjacent to their downwardly extended end portions, is substantially equal to the depth of said side members and which increases to a maximum depth midway of their length.

4. A highway drainage grating comprising side members connected by two series of spaced cross members of even height with said side members, the cross members of both series having their end portions extended downwardly, and terminating below the bottoms of said side members in the same horizontal plane, the cross members of one series alternating with those of the other series the depth of the cross members of one series gradually increasing from their downwardly extended end portions to their middle portions and the depth of the cross members of the other series between the downwardly extended end portions thereof corresponding substantially to the depth of said side members, and spaced longitudinal members extending from end to end of said grating between said side members and of substantially even height and depth therewith, said side members, cross members and longitudinal members tapering in width from the top to bottom.

HARRY C. DREIBUSS. FRED H. SPENNER.

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