US2909253A

US2909253A - Adjustable girder

Info

Publication number: US2909253A
Application number: US640477A
Authority: US
Inventors: Hinze Otto
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-03-02
Filing date: 1957-02-15
Publication date: 1959-10-20
Anticipated expiration: 1976-10-20

Description

Oct. 20,` 1959 o. H lNzE ADJUSTABLE GIRDER 2 Sheets-Sheet 1 Fiied Feb. 15, 195'/ mlrl Era

Inventar? Oct. 20, 1959 l 0, HlNzE t 2,909,253

ADJUSTABLE GIRDER Filed Feb. 15, 1957 2 sheets-sheet 2 2 '57g' 9 7 ff .Im/enten' 077'0 H/NZE @mm fem niteci States Patent Oce azs Patented Oct. I20,l 195? ADJUSTABLE GIRDER Otto Hinze, Hannover-Kleefeld, Germany Application February '15, l1957, Serial No. 640,477

Claims priority, application Germany March 2, 1956 2 Claims. (Cl. 189-37) Girders, particularly formwork girders, which consist of outer and inner girder parts and which can be telescopically increased and reduced `in length Iare known, which comprise a wedge member which is effective between the lower chords of the outer and inner girder parts to locate the girder parts 4relative to each other. The arrangement of the wedge in an imaginary plane which envelops the outer girder part, however, has given rise to diiculties in operation. Furthermore, the driving of the wedge has caused an impermissible deformation of the inherently parallel lower surfaces of inner and outer girder parts.

The girder, particularly formwork girder, which is proposed according to the invention to eliminate all these disadvantages and which consists of outer and inner girder parts and can be telescopically increased and reduced in length, comprising a wedge member which is effective between the lower chords of the outer and inner girder parts to locate the girder parts relative to each other, is characterized according to the invention in that part of the wedge member extends through the lower chord of the outer girder part. In this connection the term lower chord does not refer only to that part of a lattice girder which is stressed in tension under the usual load but also to those parts of a plate girder, e.g. a box girder, which contain the bre stressed in tension under the usual load conditions.

When the profile of the outer girder part has a lower chord consisting of a closed chord strip, the invention is characterized in that part of -the wedge member extends through a slot-like aperture of that lower chord of the outer girder part. Special advantages are obtained thereby that only that part of the wedge member extends through the lower chord of the outer girder part which is effective as a wedge so that in this case a special abutment carried by the outer girder part has to take up the wedge forces. This eliminates the need vfor special wedge ramps in the outer girder part, which would involve an increase in the clearance between the outer and inner girder parts, resulting in undesirably large differences between the overall heights of the two girder part-s; moreover, these wedge ramps deform the inner girder part in the driven condition ofthe wedge. If that part of the wedge member which is disposed between the lower chords of the outer and inner girder parts is enlarged in width relative to that part of the wedge member which extends through the lower chord of the outer girder part, the dropping of the wedge member through the aperture provided in the lower chord of the outer girder part will be prevented in a simple man-ner.

The abutment itself consists preferably of a strap which entirely or partly embraces the outer girder part in order to be able to accommodate the taper of the wedge. This 2 inner Vgirder parts from being pulled entirely apart of the overlap required for carrying strength will always be provided; thus a complete falling apart of the girder is eliminated.

Based on the known girder design having G-sectioli outer and inner girder parts, arranged so that the part with respect to the center line of the sections, which is parallel to their webs, the central part of one C-section, which central part is elective as a web, lies opposite to the central part yof the other C-section, where the central part is 'also effective as a web. In that case the wedge member extends partly through a slot in the lower side ange of the outer C-section.

The drawing illustrates a possible embodiment of the invention -as applied to a formwork girder.

Fig. 1 isv a side view of an outer girder part with aninner girder part inserted therein.

Fig. 2 is a similar view showing only the outer girder part. s

Fig; 3 is a cross-sectional view of this outer girder part.` Fig. 4 is a side view of the inner girderpart, whereas Fig. 5 is a cross-sectional view of such an inner girder part.

Fig. 6 is an enlarged side view showing the area where both girder parts overlap.

Fig. 7 is a vertical cross-sectional view taken on the line VII- VII through the formwork girder of Fig. 1, and

is particularly advantageous because that inclination can Fig. 8 is a vertical cross-sectional view takenon line VIII-VIII of Fig. l through the girders.

lFig. 9 is a sectional view taken along the lines IX-IX of Fig. 8 and shows the position of the wedge when it is wedged between the strap and the inner girder part;

Fig. 10 is a sectional View similar to that of Fig. 9 but showing the wedge when it is released ifrom its wedging position and resting upon the outergirder part.

As is apparent from the figures the outer .girder part comprises a C-section, which consists of -the solid central part 1, the

flanges

2 and 3` adjoining the central part and effective vas upper and lower chords, and the

short anges

4 and 5 continuing'said

ilanges

2 and 3. The C-section of the outer girder part is closed at several points of its length by straps 6, 'which are slightly outwardly cambered for reasons which will be set forth hereinafter. The somewhat larger closing plate 7 is disposed at the overlap with the inner girder part, which will be described later. As is apparent from Fig. 5 the inner girder part consists also of a C-section, namely, of the central part 8, the

flanges

9 and 10 effective as upper and lower chords, and the

flange extensions

11 and 12. The C-section of the inner girder part is also bridged by straps 13 at several points. An enlarged closing plate is provided at 14. Opposite to the closing plate 14 the supporting claws l5 are disposed, which are suitably forked. The

outer girder part

1, 2, 3, 4, 5 has also such supporting claws 16. The outer and inner girder parts are so related to each other that the solid central part 1 of the outer girder part lies directly opposite to the

flange extensions

11, 12 of the inner girder part and that the solid central part 8 of the inner girder part yadjoins the inside of the

flange extensions

4 and 5 of the outer girder part. The central part 8 of `the inner girder part has at 17 a screw arrangement, which in its end position shown at the right in Fig. l engages the closing plate 7 in order to establish the largest possible length of the girder. For this reason ythe straps 6 must be cambered to enable the bypassing of the screw arrangement 17, which would otherwise engage one of these straps if the girder is of insucient length.

The following means are provided for locating the inner and outer girder parts relative to each other:

A wedge member is disposed in the clearance space 3 18 left between the inner and outer girder parts because the ange 9 of the inner girder part engages the ange 2 of the outer girder part. jAs is apparent from Fig. 8 that ,wedge member .llaa-tagelang gf a T- lil ,generali Q1f1` y 'thepat't 19 'Qt th'welg. Illemlen corresponding t0 ge of the liesintheclearance space 1S, whereas theVv tliewebof the wedge member corresponding to the web of the T extends through a slot 21 in the'lower chord angl of the

section

1, 2, 3, 4, 5 of the outer girder part'. QT he wedge

4member

19, 20 atj2 2 a wedge nose, to whichfthe f orces can b e applied which are required `for driving thewedge in and out. I n accordance therewith thefo'uter boundary face 2 3V of the web 2 0 of the wedge has tlilecsSary Wedge taper aatlanabtltmetlt sgnformitia t that' wedge fairer ,and `corisiistirlg .of the Strap ,24 transmitsithe Wedgeforces Voeetmrirrg to the outer girder part T0 thisgad .the strap" ..241is"wel. ld with ,a ,Cerresponding incli1 1a,tic 1 1 -tontlre'outer girder -part,tn ore particularly, it `isvvfeltlsd at 2 5 toi the .teatral Hartl andslosing plate 7 of the outer girder'part Whatis claimed is: l t

1.'Atelescoping formwork girder comprising, in comb ination: at least one outer girder Pari CQIlSisting of a hllov/ girder', t leest .011,6 limer girder' Part lgrlgitudn'ally movabie in said outer girder' part, onechord of saidfouter girder part being formediwith van 'elongated slot which extends in the ,direction of the length Q f .Said guter slrtler pa'rtgthe ends of vsaid slot beingispaced from theends of said one chord so that s aid slot is' shorter than sadone chord, lan abutment on o uter girder part, ,and means for positioning Ysaid inner' girder part relative to said outer girder part ,sai d positioning 'means comprising a wedge member of T-shaped 'cross-section, ysaid wedge member having a wedge web forming the vertical portion of said T-shap'ed wedge member, said wedge web passing through said elongated slot and having an inclined surface engaging said abutment, and ya slide piece forming the upper cross-piece of T-shaped wedge member, said slide piece being arranged between said one chord of said outer girder partand a'chord o f said inner girder part and constituting 4the sole means for preventing passage of the entire wedge member through saidslot irrespetive of the position which said wedgemember occupies relative to Seid .Slat While ptmtttine'removel of said wedge member when inward movement of said wedge member into the interior of said outer girder part is not obstructed by said inner girder part.

2. A telescoping formwork girder comprising, in combination: at least one outer girder part consisting of a hollow girder having a C-profile, at least one inner girder part having `a v,Gfproile and being longitudinally movable in said outer girder part, said inner and outer girder partsbeing so positioned with respect to each other that theproles ofboth girder parts enclose a hollow space, one leg of said outer girder part being formed with an elongated slot which extends .in tthe direction ,of the length of said outer girder part, the ends of said slot being spaced from the ends of said one 'leg so that said slot is shorter than said one leg, ,an abutment on said outer girder part, and means for positioning said inner girder part relative to said outer girder part, said positioning means comprising a wedge member of T-shaped crosssection, said wedge member having a wedge web forming the vertical portion of said T-shaped wedge member, said wedge web passing through said elongated -slot and having an inclined surface engaging said abutment, Aand a slide piece forming the upper cross-piece of said T- shaped wedge member, said slide piece being arranged between said one -leg of said outer girder part and a -leg of said inner girder part and constituting 'the sole means for preventing passage of the entire wedge member through said slot irrespective of the position which said wedge member occupies relative to said slot while permitting removal of said wedge member when inward movement of said wedge member into the interior of said outer girder part is not obstructed by said inner girder part.

References Cited in the le of this patent UNITED STATES PATENTS 1,306,700 Kafka June 17, 1919 1,552,912 Colt Sept. 8, 1925 1,999,783 Riesbol Apr. 30, 1935 2,612,243 Campbell Sept. 30, 1952 FOREIGN PATENTS 11,297 Switzerland Mar, 17, 1896 688,782 Great Britain Mar. 11, 1953 739,057 Great Britain O ct. 26, 1,955y