US1686910A - Lever arch - Google Patents

Description

H. F. FREAsE Oct. 9, 1928.

LEVER ARCH Filed March 15, 1926 Patented Oct. 9, 1928.

HURXTHAL. F. FREasE, or CANTON, 07H10.

LEVER ARCH.

Application mea March 15, 192s. seran N6. 94,757.`

The invention relates to structures land structural members for supporting transverse loads; and the objects ot the invention are to provide structures of theA above character, more efficient than beams, trusses and the like, of usual construction, and` more economically and easily manufactured. Y l

These obects are attained in the present 1nvention by combining in a single structure parts co-acting with each other to provide arch and lever action tor the structure, and by so arranging the parts that the reactions at the bearings for the cantilever arch are normally vertical under normal condi-tions of transverse loading.

'A preferred embodiment of the invention.

is illustrated in the accompanyii'ig drawing, forming part hereof, in which Figure 1 is a top plan view of an improved lever arch structure, embodying the present invention, supported at its 'ends for use for example as a floor oist in combination with other similar joists, metal lath and concrete, not shown, according to well known methods of joist floor construction;

Fig. 2, a side elevation thereof Fig. 3, an elevation illustrating the method of cutting triangular arch struts for `the preferred structure from a rectangular plate;

Fig. 4, a .transverse cross section ot an improved lever arch, as .on lines P-4l, Figs. 1 and 2;

Fig. 5, a transverse cross section, as on lines 5 5, Figs. 1 andQ; and t Fig. 6, a transverse cross sectionof `t-.hesalrne on line 6 6, Figs. 1 and'Q..

Similar numerals refer A throughout the drawing.

The improved lever arch, indicated gener-rv ally at 1, includes triangular arch struts 2y and 2", which may be cut from a rectangular plate, as illustrated in Fig. 3. The struts 2a and 2b are arranged with their apexes 53a and 3b preferably abutting each other, as at 4,.

A pair of top arch bars 5 and 5 are secured along the upper edges 6a and 619.01? the struts 2fL and 2b, as by arc welds 7; and the bars 5 and 5, respectively, are preferably provided with terminals 5a and 5b and a and 5" extending beyond the ends of the struts 2 and 2b.

For providing tie-rod sleeves 8a and 8b.', `at

the lower outer cornersofthe' struts, U-str'aps" 9 a`-nd9b areseeured, respectively' as by rivet-'s 10, to the bases 11a and 11b' of the triangular vstruts 2A and 2b. Atie-rod 172 provided" withl threaded ends 12a and V12b extends through the `sleeves 83L and 8* respectively, and nuts 13 and 13" are screwed uponthe threaded ends 12 and 12b of the tie-rod and abutthe `U- straps as at 14a and 14". y

F or resisting lateraly displacement of the lower corners of the strut apeXes-B and 33,

a pair of guide angles' 15 ,and` 154 may be se-y cured as by are Wedin-g' to the'apex 3*." of the strut 2b, thus forminga U-notch guide foruthe apex 3 of the strut 2*".

For' providing lever end` supports for the arch structure, spaced angle end supports 16a and 16 and 16" and'16b maybe secured, as by welding, on bot'h'sides, atthel upper'oute'r corners 17 a and 17.1 of the struts=2"and2b,re` spect'iv'ely, and theaugle end supports are transversely s aced'froJinv the tiel-rodi, that isto say und'ert e normaluse of thelever arch structure, the lever end supports aref abovey the tie-rod, and the' end support-s may extend longitudinally beyond the ends of' the Lstruts any desired distance coextensive with: theter- y minals 5 ,and 5 and 5b and 5" of the xarch* bars 5 and- 5"; and the end angles and the arch bar terminalsare preferably securedv to each other as by arc'welds. Spacer plateslla and A 18b may 'be secured between they outerends of angles 5a and a and the angles 5* and 5', respectively. 1 v i Iny use the nuts 13a and 13b-may be screwed up upon the tie-rod 12-distances sufficient to provide any desired arch, as indicatedby the viding arc weld abutment collars 20a and 20' for securing the tie-rodto the U-s'traps opposite the nuts 13a and 13", respectively.

The angle end supports 1,6 and '16, and

16b and 1'6" may rest upon bea-ringsfas concrete beams Ba and Bb, and the lever arch 1 is f then in positionto carry transverse loads ap-k pliedbetween the bearings Ba and BS. t

It is a well known fact `that an ordinary arch arranged between the bearings Ba' and Y Bl and subject to the usual vertical transverse loads will set up reactiones in the bearings BfL and B"f having horizontal, as well as vertical components; which horizontal coinponents have heretofore been resisted by tierods directly connectingl to bearings B and Bb.

By reason of the fact that the stresses set up in an arch by proper loading', are allv of the same character, that is tosay compression, an arch is a very desirable type of structure for supporting transverse loads. Arch floor constructions, howeverA have not heretofore been in very general use because of the necessity vfor providingtie-rods connecting the v bearings to take up the horizontal components ofthe reaction set up in the bearings by the arch.

The lever arch. or' the present invention, when subject to the usual vertical transverse loads, set up in the bearings Ba and B", rcactions which are substantially vertical; since in the arch made up of the triangular struts 2a and 2b and the arch bars 5 and 5, any horizontal thrusts set up therein by transverse loading, are resisted and absorbed by the tierod l2.

rlhe lever portions of the improved structure l are the outwardlyextending angle supports-for each end of the structure in combination with the sleeve forming U-straps secured thereto; by which any desired upward arch may be given tothe arch bars and the struts by the heretofore described manipulation of the nuts 13d and 13b screwed upon the threaded ends l2 and 12b of the tie-rod 12,'

the line ot action ot the tie-rod being transversely spaced from the point ot contact of` the lever end supports 16'r1 and 16a', and 16 and 16h', respectively, with the bearings Ba and Bb. e

It is obvious that a sufficient arch may be given to the arch bars and struts so that mare imum transverse leading will not deflect the upper lever of the bars 5 and 5 below the horizontal.

It is moreover obvious that tlielower tie rod l2 may remain substantially horizontal during normal conditions or" loading; so that a plaster ceiling secured thereto will not be subject to any cracking deflection caused by.

transverse loads superimposed upon the upper arch bars. It is well known that ordinary beams and trusses for use in joist licor construction subject plasterI ceilings secured to their lower portions to cracking deflection caused by transverse loads applied upon their upper portions.

Itmay be seen by inspection of Fig. 3, that the arch struts require only half the weight of mateiial which would be requiredpfor the solid web plate ot an ordinary plate girder of the same external dimensions, and the same quantitv ot material in its langes as is contained in the arch bars and tie rods.

In such a plate girder the web plate is usually depended upon to resist shear loa-ds.

Shear loads are normally a maximum at the On the other hand, the use of triangulan arch struts provides a desirable form of strut member and enables the attainment of an arch action, at the same time presenting a substantially horizontal upper level for the structure, ot particular advantage in light weight floor construction. r

As illustrated in dotted lines in Fig. 2, and in full lines in Fig. 6, .re-enforcing means such as angle bars 2la and 21?, and 2lb and 211 may be provided when desired for the lower edges et the struts 2 and 2b. Such reenii'orcenient will be found desirable when the strut triangles are made ot relatively light gauge n'iaterial.

lt will be noted that structural members struts, normally substantially at or above the horizontal, should deflect below the hori zontal.

It will also be noted, that while structural:

members made according to the presentI invention are substantially as easy to inanutacture as ordinary plate girders, the improved cantilever arches herein set iorth have a large open triangular space betweenthe lower tierod and the upper arch struts, through which laterally extending pipes, wires and the line may be inserted'with even more ease than in the case ot the use trussed bar joists and the like.

I claim: y f v 1. A structural member [including triangular arch struts having apexes and bases opposite the apexes, means providing apex abutments between adjacent apeXes, and means spaced from the adjacent apexes connecting the bases opposite the apeXes, and an arch bar secured along the outer edges 'of thc arch struts.

2. A structural member including triangular arch struts having apexes and bases opposite the apertures, means providing apex abutinents between adjacent apeXes, and means spaced from the adjacent apeires connecting the bases opposite the apeXes, and lever end supports extending longitudinally beyond the bases, and an arch bar secured along` the outer edge of the arch struts. y

3. A structural member includingtriangular arch struts having apexes. and bases opposite the apeXes, means providing apex abutinents between adjacent apeXes, and means spaced from the adjacent apeXes cona tie-ro l e necting the bases opposite the rapexes, and al plurality of arch-bars secured along the outer edges of the arch struts. f f* a. A structural member including triangular arch struts having apexes and bases opposite the apexes,-1neans providing apex abutments between adjacent-j apexes, and means spaced from the' adjacent apexes connecting the bases opposite the apexcs, and lever end supports extending longitudinally beyond the bases, and a plurality ofl arch bars secured along the outer edges of the arch struts.

5. A structuralmember including triangular arch strut-s having apexes and bases opposite the apexes, means providing apex abutments between adjacent apexes, sleeves at the bases opposite the adjacent apexes and tending through the sleeve.

6. A structural member including triangular arch struts having apexes and bases opposite the apexes, means providing apexA abutmentsbetween adjacent apexes, sleeves the bases opposite the` adjacent apexes, anda tie-rod extending through the sleeve, and lever end supports extending longitudinally beyoncL the bases.

7. A structural member including arch having vouter bases, tension means connecting the outer bases of the arch and adapted 'to resistfthe end thrust thereof, and end supports on the arch extending outwardly 'l gitudinally therefrom andy transversely spaced from the tension connecting m .s.

S. A structural member including normally upper arch having outer bases, tension means below the arch connecting the outer vbases thereof and adapted to resist the end thrust thereof, and end supports on the arch extending outwardly longitudinally ther-efrom and transverselyv spaced above the tension connecting means. Y

1 1 1' 1 9. A structural` member including ai cn having outer bases, means for resisting the end thrust of the outer bases, and end supports on the arch er ending outwardly 'longitudinally 'therefrom and tra sversely spaced from the thrust resisting means.

10. A structural member .including a normally upper arch having outer bases, means below the srch for the end thrust of the and end supports on the arch extending outwardly longitudinally therefrom and transversely spaced above the thrust re. -sting means.

11. A structural member including an arch having outer bases, means for resist-ing the rend thrust of the outer bases, and lever end supports on the arch longitudinally extending outwardly beyond the'bases thereof and transversely spaced from the thrust resisting means.

12. A structural member including a normally upper arch having outer bases, means below the arch for resisting the end thrust of the bases, andlever .end ,supports on the arch longitudinally extending outwardly beyond the bases thereof and transversely `spaced above the thrust resisting means.'y

13. A structural member including an arch having outer bases, tension means connecting the outer of the arch and adapted to resist the end thrust thereof, and lever end supports on the arch longitudinally extending outwardly beyondthe bases and transversely spaced from they tension connecting means.

14:. A structural memberincluding a normally upper arch having outer bases, tension means below thek arch connecting the outer bases thereof and adapted to resist the end thrust thereof, and lever end supports on the arch longitudinally extending outwardly beyond the bases and transversely spaced above the tension connecting means.

15. A structural member including an arch `having outer bases, tension means connecting acting end supports on the arch outwardly extending longitudinally beyond the bases.

16. A structural member including an arch having outer bases, means for resisting the end thrust of the outer bases, and vertically reacting end supports on the arch outwardly extending longitudinally beyond the bases.

17 A structural member including an arch having outer' bases and a normally substantially level load supporting upper surface, tension means connecting the outer bases of the arch and adapted to resist the end thrust thereof, and end supports on the arch extending outwardly longitudinally therefrom and transversely spaced from the tension connecting means.

18. A structural member including an arch having outer bases and a normally substantially level load supporting upper surface, means for resisting the end thrust of the outer bases, and end supports on the arch extending .outwardly longitudinally therefrom and transversely spaced from the thrust resisting means.

v19. A structural member including an arch having outer bases, adjustable tension means connecting the outer bases of the arch and adapted to resist the end thrustthereof, and end supports on the arch extending outwardly longitudinally therefrom and transversely spaced from the tension connecting means. 20. A structural member including an arch having outer bases, adjustable means for resisting the end thrust. of the outer bases, and end supports on the arch extending outwardly longitudinally therefrom and transversely spaced from the thrust resisting means.

21. A structural member including' arch struts having apexes and bases opposite the apexes, means providing apex abutment between adjacent apexes, a tie-rod spaced from the adjacent apexes and connecting the bases,

and end supports on the struts extending outand lever end supports on the struts longivvardly longitudinally therefrom and transtudnelly extending outwardly beyond the 10` versely spaced from the tie-rod. bases thereof and transversely spa-Ced from 22. A'struetural member including arch the tie-rod.

'5 struts having Vapexes and bases opposite the 1n testimony that I Claim the aloove7 I have apexes, Ineens providing apex abutment behereunto subscribed my name. tween adjacent epexes, am tie-rod spaced from e the adjacent npexes and connecting the bases, HURXTHAL F. FREASE.

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