US1935772A

US1935772A - Car roof

Info

Publication number: US1935772A
Application number: US629419A
Authority: US
Inventors: Garth G Gilpin
Original assignee: PH Murphy Co
Current assignee: PH Murphy Co
Priority date: 1932-08-19
Filing date: 1932-08-19
Publication date: 1933-11-21
Anticipated expiration: 1950-11-21

Description

G. G. GILPN CAR n-oQF Nov. '21) 1933.

Filed Aug. `19, 19:52 -2 sheets-sheet 2 Patched Nov., 21, 1933 UNITED ,STATES CAR ROOF Garth G. Gilpin, Riverside, Ill., assigner to P. H.

Murphy Company, New Kensington, Pa., a corporation of Pennsylvania Application August 19, 1932. Serial N0. 629,419

9 Claims. (Cl. 10S-'5.4)

My invention relates to all metal car roofs. The principal object is to devise a design of roof sheet which is easy to manufacture, is well adapted for use in car roofs and'contributes resiliency to the roof. It consists principally in a roof sheet formed with a raised H-shaped rib disposed longitudinally of. the sheet at or near the middle thereof and decreasing in depth from the ridge towards the eaves.' It also consists in the parts and combinations of parts hereinafter described and claimed.

In the accompanying drawings, wherein like symbols refer to like parts wherever they occur,

Fig. 1 is a plan view of a portion of a. car roof embodying my invention; y

Fig. 2 is a partial cross-section thereof on the line 2-2 of Fig. 1;

Fig. 3 is a partial cross-section thereof on the line 3-3 of Fig. 1;

Fig. 4 is a partial longitudinal section along the ridge as indicated by the line 4 4 of Fig. 1; and

Figs. 5 and 6 are partial longitudinal sections on the lines 5-5 and 6 6 respectiveLv, oi Fig. 1.

'Ihe sheets 1 of the present construction span the distance between side plates 2 and have their ends turned down over and against the side plates, to which they are riveted by horizontal rivets 3, the sheets being preferably pitched. Adjacent sheets have upstanding flanges 4 along their side margins which flanges are straddled by inverted U-shaped seam caps or covers 5, said flanges and caps being riveted together by horizontalrivets. Preferably, the sidemarginal portions of the sheets are formed into panels 7 raised slightly above the adjacent portions of the roof sheets, which portions are herein considered as at the general level of the sheet.

Disposed longitudinally of each sheet at or near the middle thereof is a raised rib 4 which is of considerable depth at the vridge but which decreases in depth toward the eaves and preferably merges into the general level of the sheet above the side plates, the decrease in depth being quite gradual except at the end portions, where the decrease is somewhat more abrupt. The surface of the top 8 of this rib is substantially fiat from the ridge to each end of the rib. The portion 9 of the rib at or near the ridge is preferably of a width substantially equal to half the distance between adjacent roof seams.

Each end of said rib A is bifurcated or divided into two parallel branches 10 whose outer sides or walls 11 are continuous with the sides or walls oftherids! portionof theribA. Saidbranches are separated by an intervening `flat bottomed depression 12 which extends longitudinally of the rib and is preferably of about the same width as either of such branches. At the outer end of said depression, its bottom is at the general level of the sheets; and from this level said bottom incline's upwardly and inwardly and merges into the top of the rib at a distance from the ridge approximately equal to one-fourth of the distance between the ridge and the side plate. Thus e5 said rib is H-shaped in plan view. In longitudinal section at and near the ridge, the metal of the top of the rib is continuous the full width of the rib; whereas, in longitudinalI section through the end portions of the rib, the overall width of this rib remains substantially the same but there is a gap between the two stretches of metal constituting thetops of the branches of said rib. Whenvsheets with such H-shaped ribs are used in connection with standing seam constructions, they add nothing to the overall thickness of the roof, as the ribs need not be higher than such seams.

The operation of a roof with my H-shaped ribs' may be explainedv by comparison with similar roofs wherein the tops of the ribs are continuous from side to side throughout the length of the rib. In both cases, the rib functions after the manner of a beam, that is, the metal in the top of the rib acts in compression and the metal in the bottoms of the channel acts in tension. As the compressive stress in 'a beam is a maximum midway between its ends and gradually decreases towards its ends, it is obvious that, for equal carrying strength, less metal is required in the vtop of the rib near the ends thereof than is required near the middle thereof. It is also obvious that if there is enough metal in the top of a plain or non-bifurcated rib in and near the ridge for proper beam action, then thereis more metal in the top of the end portion of said rib than is required for the strength of the rib. On the other hand, lessening the amount of the metal towards the ends of the rib decreases the stiffness of the ribs. In conformity with these prin- 100 Vciples, applicants H-shaped rib has a great load carrying capacity due to the metal-being continuous from side to side of the rib throughout its ridge region wherein the compression stress is greatest; and still it has a sufilcient degree of 105 -resiliency, without being springy, due to the bifurcation of the rib and the consequent decrease in the amount of metal in the top thereof in the neighborhood of the ends and the concomitant formation of additional vertical web 1 10` members. Thus. as the bifurcation begins beyond the region of maximum compression stress, the load carrying capacity of the rib is not decreased, while the gradual depression of the middle portion of the ends of the ribs makes it feasible to obtain the desired resiliency without undue springiness. Consequently, the roof is not only light, thin and strong but is well adapted to.

yield resiliently to stresses which might disrupt a rigid roof and has the special merit of cushioning the roof againsty such shocks as are occasioned by low joints in the railway track and the like.

What I claim is:

1. A car roof sheet comprising a substantially flat-topped raised H-shaped rib disposed lengthwise thereof, the portions between the branches of the H being substantially flat and of uniform width and rising from the plane of the sheet at their eaves ends to the plane of the top of the rib at their ridge ends.

2. A car roof sheet comprising a substantially flat-topped raised H-shaped rib disposed lengthwise thereof, said rib being located near the middle of the sheet and being approximately one-half as' wide as said sheet, the portions between the branches of the H being substantially fiat-and of uniform width and rising from the plane of the sheet at their eaves ends to the plane of the top of the rib at their ridge ends.

3. A car roof sheet comprising a substantially nat-topped raised H-shaped rib disposed longitudinally of the sheet in the middle thereof, said rib decreasing in depth from the ridge towards the eaves with its ends merging into the plane of the sheet short of the ends of said sheet, the portions between the branches of the H being substantially flat and of uniform width and .rising from the plane of the sheet at their eaves ends to the plane of the top of the rib at their ridge ends.

4. A car roof comprising side plates, roof sheets with their ends secured thereto and with upstand- 4ing side flanges capped and secured together by horizontal rivets, each roof sheet comprising a raised H-shaped rib disposed lengthwise of the sheet near the middle thereof and extending beyond the inner edges. of theside plates.

5. A car roof comprising roof sheets with up.- standing side flanges capped and secured together by horizontal rivets, each roof sheet comprisingA a substantially flat-topped raised H- shaped rib disposed lengthwise of the sheet near the middle thereof and being approximately onehalf as Wide as `said sheet, the portions between the branches of the H being substantially flat and of uniform width and rising from the plane of the sheet at their eaves ends to the plane of the top of the rib at their ridge ends.

6. A car roof comprising roof sheets with upstanding side flanges capped and secured together by horizontal rivets, each roof sheet comprising a substantially fiat-topped raised H- shaped rib disposed longitudinally of the sheet in the middle thereof, said rib decreasing in depth from the ridge towards the eaves with its ends merging into the plane of the sheet beyond the inner edges of the side plates.

7. A car roof comprising roof sheets having upstanding flanges along their side margins rig-n idly secured together, each sheet having a substantially flat-topped raised H-shaped rib along its longitudinal middle portion, the cross-sectional area of said rib in the neighborhood of the ridge being substantially equal to the sum of the cross-sectional'areas of the lower side portions of said sheet.

8. A car roof comprising roof sheets whose side margins are rigidly secured together, said sheets comprising a raised H-shaped rib disposed longitudinally of the sheet in the middle thereof and decreasing in depth from the ridge towards the eaves with its ends merging into the plane of the sheet above the side plates thereof.

9. A car roof comprising roof sheets whose side margins are rigidly secured together, each sheet comprising a substantially fiat-topped raised H-shaped rib disposed lengthwise of the sheet near the middle thereof and being approximately one-half as wide as said sheet, the portions between the branches of the H being substantially fiat and of uniform width and rising from the plane ofthe sheet at their eaves ends to the plane of the top of -the rib at their ridge ends.

GARTH G. GILPIN.