US3352081A - Extensible girder construction and clamping means therefor - Google Patents

Extensible girder construction and clamping means therefor Download PDF

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Publication number
US3352081A
US3352081A US385598A US38559864A US3352081A US 3352081 A US3352081 A US 3352081A US 385598 A US385598 A US 385598A US 38559864 A US38559864 A US 38559864A US 3352081 A US3352081 A US 3352081A
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United States
Prior art keywords
girder
lower chord
pressure member
pressure
clamping
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Expired - Lifetime
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US385598A
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English (en)
Inventor
Hunnebeck Emil Mauritz
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Huennebeck AG
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Huennebeck AG
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    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G11/00—Forms, shutterings, or falsework for making walls, floors, ceilings, or roofs
    • E04G11/36—Forms, shutterings, or falsework for making walls, floors, ceilings, or roofs for floors, ceilings, or roofs of plane or curved surfaces end formpanels for floor shutterings
    • E04G11/48—Supporting structures for shutterings or frames for floors or roofs
    • E04G11/50—Girders, beams, or the like as supporting members for forms
    • E04G11/54—Girders, beams, or the like as supporting members for forms of extensible type, with or without adjustable supporting shoes, fishplates, or the like
    • E04G11/56—Girders, beams, or the like as supporting members for forms of extensible type, with or without adjustable supporting shoes, fishplates, or the like of telescopic type

Definitions

  • the present invention relates to clamping means for temporary extensible girder units.
  • extensible girder units have increased more and more each year in view of the fact that such girder units can easily be adapted to various spans and can be employed over and over again.
  • the basis for the employment of extensible girder units consists in their economy which in its turn depends primarily on the price, ie on the cost of production of the girder units. Therefore, it is imperative to keep the Weight per unit of load carrying capacity of the girder unit as low as possible.
  • the inner girder is designed as a lattice girder or as a plate girder with relatively thin plate web, the diificulty of absorbing the clamping pressure on the inner girder increases. This pressure multiplied by the safety factor is to be absorbed by the diagonal braces of the lattice girder or the web of the plate girder.
  • a clamping device comprising a relatively long and narrow pressure member provided with two supporting surface sections spaced from each other in the longitudinal direction of said pressure member and an intermediate surface section between the supporting surface sections, said supporting surface sections elevated relative to said intermediate surface section for engagement with and conveying clamping pressure onto the lower chord of the inner girder of an extensible girder unit, and means for engaging the lower chord of an outer girder of the extensible girder unit and said pressure member adjacent the intermediate surface section and for conveying clamping pressure thereto adjacent the intermediate surface section between the supporting surface sections.
  • FIGURE 1 illustrates a front view of a clamping means according to the present invention in the form of a clamping screw
  • FIGURE 2 is a side view of FIGURE 1;
  • FIGURE 3 illustrates a side view of a modified clamping means according to the invention in the form of clamping wedges
  • FIGURE 4 is a fragmentary view showing the connecting point of the clamping means of FIGURE 2 on the outer girder of an extensible girder unit;
  • FIGURE 5 is a perspective view of the clamping means of FIGURES 1 and 2 with the transverse bridge removed for the purpose of better demonstration;
  • FIGURE 6 is an elevation of the extensible girder unit, showing a combination of the outer girder and the inner girder with a clamping device.
  • the clamping means according to the present invention for use in connection with extensible girder units, especially girder units with a lattice inner girder, is so designed that the clamping means rests on the lower chord of the inner girder by means of a pressure member in the form of a two-arm lever in such a way that the clamping force is conveyed to the lower chord at two supporting surfaces only which are located at the ends of the pressure member, while the point of attack of the clamping force is located between said supporting surfaces.
  • wedges have heretofore been employed as clamping means which wedges, however, rest along their entire length on the lower chord of the inner girder.
  • pressure members have also been inserted between a pressure screw and the inner girder inorder to distribute the pressure over the lower chord of the inner girder.
  • the pressure distribution is rather incomplete. In other words, there occurs, nevertheless, a more or less concentrated pressure transfer and thus a resultant force which the inner girder has to withstand at any portion thereof. This means that with a lattice inner girder, when this force attacks below a nodal point of the lattice-work (Case A), this force has to be absorbed solely by the diagonal braces meeting at the nodal point.
  • the clamping force is distributed over the diagonal braces of the neighbouring nodal points.
  • the force to be conveyed is the same as in the above mentioned Case C.
  • the present invention makes it possible to better exploit the diagonal braces than is the case where the clamping force is conveyed to the lower chord of the inner girder at a single point only (Cases A and B). Furthermore, the bending stress which is superimposed upon the tensile stress produced in the lower chord by the load resting upon the girder unit is reduced to one half.
  • the clamping means designed in the form of a pressure screw and provided in a transverse bridge between the side cheeks of the outer girder has a head which widens toward the upper end upon which the pressure member rests;
  • the transverse bridge is provided with jaws located laterally of the pressure member, the pressure memberbeirig guided between the jaws in any working position thereof, and
  • the screw has such a length that when occupying itshighest position, the pressure member is adapted to be laterally slipped off from the screw head over the jaws of the transverse bridge.
  • clamping means namely the transverse bridge, screw and pressure member
  • this construction of clamping means makes possible a lateral guiding of the pressure member and thereby avoids the danger of a lateral bending of the clamping screw in view of the pressure exerted by the inner girder.
  • the pressure member is additionally provided with lateral jaws, the lower chord of the inner girder will be guided whereby it will be protected against lateral displacement and against buckling under the clamping force.
  • the clamping means illustrated therein comprises a transverse bridge 7, a clamping screw 8 and a pressure member 23.
  • Pressure member 23 has two supporting surfaces 24 between which a depression 25 is provided, and has two lateral jaws or walls 26 for guid ing therebetween the lower chord of the inner girder of an extensible girder unit, said lower chord resting on said supporting surfaces 24.
  • the bottom side of said pressure member 23 is provided with two protrusions 27 of which the surfaces 28 facing each other form a part of a dovetail-shaped recess.
  • the lower end of the clamping screw 8 is provided with an eye 29 for receiving a bolt or the like for turning the screw.
  • the upper end of screw 8 has a head 37 of a truncated cone shape.
  • the generatrices of the cone define the same angle as the surfaces 28 of the protrusions of pressure member 23 which embrace the screw head 37.
  • Transverse bridge 7 is provided with lateral jaws 30 between which the pressure member 23 is guided.
  • the lateral jaws 30 have shoulders 31 by means of which the transverse bridge rests on the lower chords 6 (FIGS. 4 and 6) of the side cheeks of the outer girder of an extensible girder unit 2 and is welded by welding spot 33 to lower chords 6.
  • the bottom surfaces 32 and 33 of the shoulders 31 form an angle with each other which corresponds to the bend or angle which the lower chord 6 of the outer girder 2 forms at the connecting point of the clamping means where said lower chord 6 leads upwardly to the upper chord 3 of the outer girder 2.
  • This arrangement makes it possible to connect the transverse bridge 7 to the lower chord 6 of the outer girder 2 so that the axis of the screw passes through the nodal point of the lattice work of the outer girder 2.
  • the width of the shoulders 31 at the point of attack of diagonal braces 5 of the outer girder 2 is dimensioned sufficiently small so that the shoulders 31 can be connected to the lower chords 6 of the outer girder and to the diagonal braces 5 by a single correspondingly large welding spot 38 as shown in FIG. 4.
  • the lower chord 4 of the inner girder 4a rests on the supporting surfaces 24 of the pressure member 23 (not shown in FIG. 6) for better demonstration.
  • the pressure member When the clamping means occupies its position of operation, the pressure member is located below the illustrated position and is enclosed by the lateral jaws 3t ⁇ of the transverse bridge.
  • that portion of the transverse bridge which is provided with the screw thread is offset in downward direction with regard to the shoulders 31. This is of great advantage in order to obtain the necessary height of the free profile of the outer girder for the inner girder and the pressure member and for permitting the girder unit to be lowered a sufficient extent.
  • FIG. 3 illustrates a section through a transverse bridge 7a.
  • bridge 7a has a curved sup porting surface 34 for a pressure member 23a which occupies its operative position and is designed in the form of a wedge.
  • Pressure member 23a differs from pressure member 23 of FIGS. 1 and 2 in that its lower surface 35 forms an angle with the plane in which the supporting surfaces 24, are located, said angle corresponding to the required lip angle of the wedge.
  • the arrangement of FIG. 3 is equipped with abutments 36 which prevent the wedge 23a from being knocked out of the transverse bridge 7a and thereby also prevents any danger of the wedge 23a getting lost.
  • a combination comprising an extensible girder unit having an inner girder with a first lower chord and having an outer girder with spaced side cheeks each having a second lower chord and struts extending from said second lower chord to an upper chord and corresponding diagonal braces, a relatively long and narrow pressure member provided with two supporting surface sections spaced from each other in the longitudinal direction of said pressure member and an intermediate surface section between said supporting surface sections, said two supporting surface sections elevated relative to said intermediate surface section for engagement with and conveying clamping pressure onto said first lower chord of said inner girder, said pressure member having a bottom side provided with recess means adjacent said intermediate surf-ace section, a rotatable screw bolt having a head detachably engaging said recess means for supporting said pressure member and conveying clamping pressure thereto, and a transverse bridge member including surfaces resting on said second lower chords of said side cheeks of said outer girder and provided with a threaded bore in threaded engagement with said threaded bolt, said surfaces of said bridge member having a contour
  • a clamping device comprising; a relatively long and narrow pressure member provided with two supporting surface sections spaced from each other in the longitudinal direction of said pressure member and an intermediate surface section between said supporting surface sections, for engagement with and conveying clamping pressure onto the lower chord of the inner girder of an extensible girder unit, and means for engaging the lower chords of an outer girder of said extensible girder unit and said pressure member adjacent said intermediate surface section and for conveying clamping pressure thereto adjacent said intermediate surface section between said supporting surface sections.
  • a clamping device comprising; a wedge member having a top surface with two supporting surface sections spaced from each other in the longitudinal direction of said wedge member and an intermediate surface section between said supporting surface sections, said two supporting surface sections elevated relative to said intermediate surface section for engagement with and conveying clamping pressure onto the lower chord of the inner girder of an extensible girder unit, said wedge member including a bottom surface portion adjacent said intermediate surface section, and means for engaging the lower chords of an outer girder of said extensible girder unit and having an upper crowned surface for engaging said bottom surface portion of said wedge member and for conveying clamping pressure thereto adjacent said intermediate surface section between said supporting surface sections.
  • a clamping device comprising; a relatively long and narrow pressure member provided with two supporting surface sections spaced from each other in the longitudinal direction of said pressure member and an intermediate surface section between said supporting surface sections, said two supporting surface sections elevated relative to said intermediate surface section for engagement with and conveying clamping pressure onto the lower chord of the inner girder of an extensible girder unit, said pressure member including a bottom side provided with recess means adjacent said intermediate surface section, a rotatable screw bolt having a bolt head detachably engaging said recess means for supporting said pressure member and conveying clamping pressure thereto, and a bridge member provided with two spaced side walls mounted on the lower chords of an outer girder of said extensible girder unit, said bridge member having an upright threaded bore therethrough threadedly engaging said bolt to permit rotation of said bolt in said bore, and said bridge member provided with lateral guiding means laterally detachably
  • said recess means is formed by a groove extending transverse to the longitudinal extension of said pressure member and having a dovetailed cross section
  • said bolt head comprises an inverted truncated cone of a cross section conforming to said dovetailed cross section of said groove.
  • FRANK L. ABBOTT Primary Examiner.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Mechanical Engineering (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Bridges Or Land Bridges (AREA)
  • Mutual Connection Of Rods And Tubes (AREA)
  • Forms Removed On Construction Sites Or Auxiliary Members Thereof (AREA)
US385598A 1963-09-09 1964-07-28 Extensible girder construction and clamping means therefor Expired - Lifetime US3352081A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
LU44403 1963-09-09

Publications (1)

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US3352081A true US3352081A (en) 1967-11-14

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US385598A Expired - Lifetime US3352081A (en) 1963-09-09 1964-07-28 Extensible girder construction and clamping means therefor

Country Status (6)

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US (1) US3352081A (de)
AT (1) AT253759B (de)
DE (2) DE1534971C3 (de)
DK (1) DK115951B (de)
LU (1) LU44403A1 (de)
NL (1) NL6410459A (de)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB739057A (en) * 1952-05-03 1955-10-26 Rapid Metal Developments Ltd Improvements relating to telescopic beams particularly for supporting shuttering
US2974762A (en) * 1952-09-23 1961-03-14 Hunnebeck Emil Mauritz Girder units
FR1257884A (fr) * 1960-03-28 1961-04-07 Firme Antonio Orsenigo Poutrelle à treillis extensible avec dispositif mobile de blocage des éléments en pénétration
FR1275163A (fr) * 1960-11-24 1961-11-03 Poutre réglable de coffrage
CA633673A (en) * 1962-01-02 M. Hunnebeck Emil Temporary supporting girder
US3045786A (en) * 1960-03-23 1962-07-24 Hico Corp Of America Form supporting girder for use in concrete construction
CH366960A (it) * 1958-08-09 1963-01-31 Metalliche Rocca Mario Costruz Trave metallica di sopporto estensibile
US3180463A (en) * 1960-12-30 1965-04-27 Seco Steel Equipment Company P Composite girder assembly
US3240021A (en) * 1961-07-22 1966-03-15 Mines Domanlales De Potasse D Mine roof supporting structure

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA633673A (en) * 1962-01-02 M. Hunnebeck Emil Temporary supporting girder
GB739057A (en) * 1952-05-03 1955-10-26 Rapid Metal Developments Ltd Improvements relating to telescopic beams particularly for supporting shuttering
US2974762A (en) * 1952-09-23 1961-03-14 Hunnebeck Emil Mauritz Girder units
CH366960A (it) * 1958-08-09 1963-01-31 Metalliche Rocca Mario Costruz Trave metallica di sopporto estensibile
US3045786A (en) * 1960-03-23 1962-07-24 Hico Corp Of America Form supporting girder for use in concrete construction
FR1257884A (fr) * 1960-03-28 1961-04-07 Firme Antonio Orsenigo Poutrelle à treillis extensible avec dispositif mobile de blocage des éléments en pénétration
FR1275163A (fr) * 1960-11-24 1961-11-03 Poutre réglable de coffrage
US3180463A (en) * 1960-12-30 1965-04-27 Seco Steel Equipment Company P Composite girder assembly
US3240021A (en) * 1961-07-22 1966-03-15 Mines Domanlales De Potasse D Mine roof supporting structure

Also Published As

Publication number Publication date
DE1534971A1 (de) 1969-08-28
AT253759B (de) 1967-04-25
DE1908377U (de) 1965-01-14
DE1534971C3 (de) 1973-09-27
NL6410459A (de) 1965-03-10
LU44403A1 (de) 1963-11-09
DE1534971B2 (de) 1973-03-08
DK115951B (da) 1969-11-24

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