WO1990008867A1 - Barres de renforcement de beton et leurs raccords - Google Patents

Barres de renforcement de beton et leurs raccords Download PDF

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Publication number
WO1990008867A1
WO1990008867A1 PCT/GB1990/000092 GB9000092W WO9008867A1 WO 1990008867 A1 WO1990008867 A1 WO 1990008867A1 GB 9000092 W GB9000092 W GB 9000092W WO 9008867 A1 WO9008867 A1 WO 9008867A1
Authority
WO
WIPO (PCT)
Prior art keywords
bar
jaws
section
ram
opening
Prior art date
Application number
PCT/GB1990/000092
Other languages
English (en)
Inventor
John David Clapson
John Howard Rogers
Original Assignee
Square Grip Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Square Grip Limited filed Critical Square Grip Limited
Publication of WO1990008867A1 publication Critical patent/WO1990008867A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21F—WORKING OR PROCESSING OF METAL WIRE
    • B21F5/00—Upsetting wire or pressing operations affecting the wire cross-section
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/16—Auxiliary parts for reinforcements, e.g. connectors, spacers, stirrups
    • E04C5/162—Connectors or means for connecting parts for reinforcements
    • E04C5/163—Connectors or means for connecting parts for reinforcements the reinforcements running in one single direction
    • E04C5/165—Coaxial connection by means of sleeves

Definitions

  • This invention relates to reinforcement bars and means by which they may be adapted for coupling to each other and to surrounding for work in a reinforced concrete element. It relates particularly to the end of such bars and their adaptation to receive a male screw thread thereon.
  • the present invention is directed at a coupling system for reinforcement bars and related techniques which takes advantage of the benefits of enlarged bar ends as described above, but reduces the work required to form an enlarged end prior to formation of a screw thread thereon.
  • a concrete reinforcement bar according to the invention having a substantially uniform cross-section intermediate its ends is enlarged at at least one end thereof relative to such intermediate cross-section and formed with a tapering external male thread on the enlarged end.
  • the mean root diameter of the thread is at least equal to the diameter of the intermediate cross section of the bar, and preferably the minimum root diameter of the external thread is at least equal to the diameter of the intermediate cross-section of the bar.
  • the invention provides that a substantial axial length of the tapered thread has a root diameter at least equal to the diameter of the intermediate bar cross-section.
  • the adoption of a tapered thread on an enlarged bar end has a number of advantages. Primarily, the enlargement of a bar end by cold or hot working tends to result in a slight taper in any event, and thus by applying a tapered thread less working is required to achieve sufficient enlargement to apply the thread thereto.
  • the axial length of the thread in which the root diameter is greater than the intermediate diameter also strengthens the subsequent coupling where the potential tensile forces are likely to be greatest. Additionally, the step of coupling itself is simplified.
  • a tapered thread can be tightened in much fewer turns, and is self- locking when the root diameters of the male and female threads are matched.
  • Reinforcement bars according to the invention are almost invariably of metal, and normally formed in steel. Ends thereof can be enlarged by cold or hot working, although cold working is preferred. Bars are also usually hardened at the surface, and the enlargement technique adopted should be such as to at least retain the surface properties.
  • a coupling system between reinforcement bars according to the invention will have the end of each bar received in a coupler having a complementary female tapering thread formed in each of at least two openings therein.
  • the openings in the coupler will normally be aligned, and usually contiguous.
  • the female threads may be of the same or opposite senses depending on the threads formed on the bar ends and the particular application. Usually the female threads in the coupler will be of the same sense, as will the male threads on the bars, for ease of manufacture, and for ease of assembly of the system.
  • a coupler may of course have more than two openings, any or all of which can receive a bar end. For example, a coupler may have four orthogonally oriented openings if the reinforcement bars are to be laid in a mesh formation.
  • the present invention also relates to apparatus for forming an end portion on a reinforcement bar with an enlarged cross-section relative to the bar cross-section intermediate its ends.
  • Apparatus comprises a frame defining an axis; an holding member traversing the frame and formed with an opening substantially aligned with the frame axis, the wall of the opening tapering in one direction along the axis; a plurality of jaws disposed in the opening and adapted to clamp the reinforcement bar therebetween upon movement into the opening in one direction; and a ram fixed relative to the holding member.
  • the ram is operable to advance a ram head along the frame axis towards the jaws, and means are provided for locating a reinforcement bar along the frame axis with an end thereof protruding from the jaws and towards the ram end.
  • either or preferably both of the ram head and the jaws will be provided with a recess located substantially on the axis of the frame to receive the axial extremities of the enlarged end portion.
  • the recess on the ram will normally be closed at the base thereof. That on the jaws will be in the form of corresponding plurality of depressions in the inner edges of the jaws which together form a substantially annular recess. In some cases, bevelled or chamfered edges on the jaws will be sufficient in this respect.
  • the jaws in apparatus according to the invention will normally have an external surface which substantially matches the internal surface of the opening in the holding member, but the internal surface which engages the reinforcement bar may take any suitable form. It may be deliberatey roughened or formed with teeth so as to enhance its grip on the bar, although particularly where the bar itself is formed with ribs or some other surface projections, this can be unnecessary.
  • the internal surfaces of the jaws define a plurality of planar surfaces surrounding the frame axis.
  • two jaws are used which together define four substantially orthogonal planar surfaces surrounding the frame axis.
  • the advance of the ram head should preferably be controlled to achieve the desired degree of deformation of the bar end.
  • This latter technique has the advantage of accommodating dimensional irregularities in the bar itself, and of course prevents the ram head from advancing against the jaws in the event of unintentional operation or failure of the jaws to properly clamp the bar.
  • the jaws When using apparatus according to the invention, after enlargement of the bar end and withdrawal of the ram head, the jaws may remain in clamping engagement around the bar within the opening in the holding member. Provision may also be made for forcing the jaws out of the opening and towards the withdrawn ram head, and where a preliminary gripping device is employed as discussed above, this may be adapted to operate in a reverse mode to this end.
  • Figure 1 shows in partial cross-section two reinforcement bars received in a tubular coupler
  • Figures 2A, 2B and 2C show successive stages in the formation of a tapered male thread on the enlarged end of the reinforcement bar
  • Figure 3 shows a plan view of apparatus according to the invention for enlarging a bar end.
  • Figure 1 shows the end of two slightly different concrete reinforcement bars 2, 4 connected to the same coupler 6.
  • Each bar 2, 4 has a core 8, 10 with a pluarality of partially circumferential projections 12 thereon. Both bar ends are enlarged relative to the bar cross-section remote from the coupler 6, and are provided with tapered screw threads 14 on the enlarged sections.
  • the thread 14 on the bar 2 is right handed.
  • the thread 14 on the bar 4 is left handed.
  • the overall dimensions, pitch and taper of the thread 14 is the same on each bar end.
  • a standard 60° thread with a 2mm pitch is suitable, although other thread geometries may be adopted.
  • the coupler 6 is formed with corresponding right and left handed threads enabling it to be turned in one direction to simultaneously tighten the threaded connection with each bar 2, 4.
  • the bars 2, 4 shown in Figure 1 differ only in the base diameter of the respective cores 8, 10.
  • the diameter of the core 8 in bar 2 is less than the diameter of the core 10 in bar 4. More particularly, the diameter of the core 8 is equal to or less than the minimum root diameter of the thread 14 at the end of bar 2.
  • the diameter of core 10 is substantially equal to or less than the mean root diameter of the thread 14 on bar 4.
  • Figure 1 illustrates two bars of different core diameter connected to the same coupler 6 for the purpose of illustration only. While in some applications, bars of different core diameters would be coupled in this way, it is unusual.
  • the core diameter and thread on a reinforcement bar will be adapted for use with only one size of coupler to ensure that only reinforcement bars of one core diameter are used in a given application. It is normally not recommended for on-site work to use couplers with opposite threads, and threads of the same sense will usually be used at both end of the coupler, so that couplers and bars can be successively connected by screwing onto one another in the same sense.
  • FIG. 2A shows the end of a bar prior to the formation of a thread 14 thereon.
  • the bar comprises a core section 10 of substantially uniform cross-section, with ribs 12 projecting from the surface thereof.
  • Figure 2B shows the bar end after it has been cold worked to enlarge the end section thereof.
  • the ribs 12 have been brought closer together in the enlarged section, where the diameter of the core 10 has been increased by around 20%.
  • the initial length of the section to be enlarged is normally around two times the bar core diameter, and this length is reduced by around 25% to achieve the desired core diameter enlargement.
  • Figure 2B the shape of the enlarged end section of the bar has a slightly bowed profile, with the maximum core diameter developing substantially centrally within the axial length of the enlarged section.
  • An enlarged bar end as shown in Figure 2 is thus not readily suitable for the formation of a parallel thread thereon.
  • Figure 2C shows the enlarged bar end of Figure 2B in which a tapering thread 14 had been cut or roll formed thereon. It will be readily apparent that the minimum pitch diameter of the thread 14 is less than the minimum diameter at the end of the enlarged section of Figure 2B , enabling the thread to be directly cut thereon.
  • Figures 2 show a bar similar to that identified as 4 in Figure l, in which the minimum root diameter of the thread 14 is less than the diameter of the core 10.
  • Figure 2C shows in schematic elevation apparatus according to the invention for enlarging or upsetting the end of a bar 4 to form an enlarged end section of the kind illustrated in Figure 2B.
  • the apparatus comprises a frame 16 which defines an axis 18.
  • an holding member 22 Mounted on the frame 16 by bolts 20 is an holding member 22, a portion 24 of which traverses the frame 16 and the axis 18. In the portion 24 is formed a conical opening with its larger end directed to the left as shown. Installed within the opening 26 is a plurality of jaws 28 with external conical surfaces which complement the wall of the opening 26 such that upon movement to the right as shown into the opening 26 the jaws converge upon the axis 18.
  • a hydraulic cylinder 30 with connections 32.
  • a piston 34 extends from the cylinder 30 to a bracket 36.
  • the cylinder 30 may be actuated to urge the bracket 36 to the left as shown along the axis 18 to release the jaws 28 from the opening 26 as will be described below.
  • an hydraulic ram 38 Also mounted in the frame 16, and fixed relative to the holding member 22 is an hydraulic ram 38. With connections 40.
  • the ram has a ram head 42 which is in juxtaposition with the exposed faces of the jaws 28 along the axis 18.
  • the connections 40 are connected to a source of fluid under pressure, and actuation of the ram urges the head 42 to the right as shown along the axis 18.
  • a limit switch (not shown) may be mounted either on the holding member 22 or the end face of a jaw 28 to prevent excessive advance of the ram head 42.
  • the limit switch may be coupled to the connections 40 or the source of fluid under pressure to depressurise the ram when it reaches the specified limit of advance.
  • the limit switch is set to act in response to the spacing between the exposed face of the jaws 28 and the ram head 42 falling below say 4 mms.
  • a reinforcement bar 4 is located in the frame 16 with its end 44 protruding from the exposed face of the jaws 28 as shown. Additional support for the bar 4 is provided remote from the holding member 22 by an adjustable clamp 46.
  • the clamp 46 is adapted to only lightly engage the bar 4. It is adjustable so as to accommodate bars of differing diameter, but should not substantially restrict the movement of the bar 4 along the axis 18. With the bar 4 mounted in the apparatus, and the ram head 42 withdrawn, the protruding length of the bar end 44 is adjusted to approximately twice the bar diameter. The jaws 28 are then moved to the right while retaining the protruding length of the bar end 44 at this value, until the bar is firmly held in the opening 26.
  • the ram 38 is actuated, and the ram head 42 moves to the right as shown along axis 18, up to and beyond its engagement with the bar end 44. Its progessive advance beyond engagement with the bar end 44 deforms the end while simultaneously applying an axial force to the jaws 28 which tightens their radial engagement with the bar 4 in the opening 26.
  • the ram 38 will normally have a capacity around 150 tonnes, and the apparatus described will normally be suitable for bars of diameter in the range 16mm to 40mm.
  • the degree of advance of the ram head 42 will be selected according the degree of enlargement required at the bar end 44.
  • the ram is depressurised and the ram head 42 withdrawn.
  • the cylinder 30 is then activated to urge the jaws 28 to the left as shown, enlarging the space between them to an extent sufficient to withdraw the enlarged bar end 44 therethrough to the right as shown along the axis 18.
  • the jaws 28 Upon being urged to the left, the jaws 28 will normally be separated as they are carried over the enlarged end.
  • resilient spring mechanisms may be deployed to draw them outwards as they are released. Alternatively, they may be mounted in guideways on the wall of the opening 26 which retains them on convergant paths of movement at all times.
  • the ram head 42 is formed with a recess 46 for receiving the end, and the inner edges of the jaws 28 facing the ram head 42 are beveled or chamfered.
  • the provision of these features extends the length of the bar end that can protrude from the jaws 28 without risk of excessive deformation. Normally though, the protruding length should not exceed 2.5 times the diameter of the bar 4.

Landscapes

  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Mechanical Engineering (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Reinforcement Elements For Buildings (AREA)

Abstract

Une barre (2,4) de renforcement de bêton comporte des extrémités élargies sur lesquelles on forme des filetages (14) extérieurs coniques. Les extrémités sont adaptées pour être reçues dans des raccords (6) de sorte que l'on puisse assembler une barre ou une formation d'accouplement de barres étendue. Une machine d'élargissement des extrémités des barres comporte un élément de maintien (22) à mâchoires (28) afin de serrer la barre (4) avec son extrémité (44) saillante vers un pilon (38). Ledit pilon est doté d'une tête (42) avançant pour venir au contact de l'extrémité (44) saillante de la barre, afin d'élargir la section transversale de cette dernière.
PCT/GB1990/000092 1989-01-26 1990-01-23 Barres de renforcement de beton et leurs raccords WO1990008867A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8901723.0 1989-01-26
GB8901723A GB2227802A (en) 1989-01-26 1989-01-26 Concrete reinforcement bar couplings and apparatus for enlarging bar ends

Publications (1)

Publication Number Publication Date
WO1990008867A1 true WO1990008867A1 (fr) 1990-08-09

Family

ID=10650653

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1990/000092 WO1990008867A1 (fr) 1989-01-26 1990-01-23 Barres de renforcement de beton et leurs raccords

Country Status (3)

Country Link
AU (1) AU4942690A (fr)
GB (1) GB2227802A (fr)
WO (1) WO1990008867A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0448488A1 (fr) * 1990-03-23 1991-09-25 Etablissements A. Mure Liaison mécanique de ronds à béton, manchon de liaison permettant la mise en oeuvre de la dite liaison et procédé de réalisation d'une telle liaison
FR2671365A1 (fr) * 1991-01-04 1992-07-10 Techniport Sa Liaison mecanique de ronds a beton, manchon de liaison permettant la mise en óoeuvre de la dite liaison, et procede de realisation d'une telle liaison.
US5308184A (en) * 1989-01-27 1994-05-03 Techniport S.A. Method and apparatus for mechanically joining concrete-reinforcing rods
EP0947642A3 (fr) * 1998-03-31 2000-01-12 Gyeng Ok Chung Procédé de réalisation d'une extrémité de jonction à une barre déformée pour béton armé, barre déformée réalisée au moyen de ce procédé et structure de jonction pour barre déformée
EP1048798A1 (fr) * 1999-04-22 2000-11-02 Ancotech Ag Procédé de fabrication de fers à béton à filet extérieur
SG112795A1 (en) * 1998-03-31 2005-07-28 Gyeng Ok Chung Method of working connection end of deformed bar for reinforcing concrete, deformed bar worked by the method and structure of connecting deformed bar

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI922525A0 (fi) * 1992-06-01 1992-06-01 Tartuntamarkkinointi Oy Foerfarande foer skaerning av en gaenga i en staong.
US5776001A (en) 1994-02-16 1998-07-07 Ccl Systems Limited Thread formation
AUPO219296A0 (en) * 1996-09-06 1996-10-03 Alan H. Reid Pty Ltd Threaded fastener having insertion depth indicator
US6880224B2 (en) 2003-06-25 2005-04-19 Erico International Corporation Deformed reinforcing bar splice and method
GB2426012A (en) * 2005-05-12 2006-11-15 Screwfast Foundations Ltd Modular helical anchoring system
CN112144760A (zh) * 2020-08-20 2020-12-29 中建二局第一建筑工程有限公司 一种钢筋续接结构

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2255096A (en) * 1936-03-16 1941-09-09 B W Mfg Company Heading machine
US3333456A (en) * 1964-12-28 1967-08-01 Prescon Corp Machine for cold heading wire
US3415552A (en) * 1966-11-29 1968-12-10 Howlett Machine Works Splicing metallic reinforcing rods with a threaded coupling sleeve
FR2435576A1 (fr) * 1978-09-07 1980-04-04 Lande Irving Procede et dispositif pour la jonction d'aboutement de barres d'armatures a beton
EP0017462A1 (fr) * 1979-04-05 1980-10-15 Geoffrey Arnold Snell Procédé pour la fabrication des articles en fil métallique
US4237942A (en) * 1975-11-21 1980-12-09 Hans Dietrich Apparatus to produce an anchor on a tendon twisted of several steel wires
US4486991A (en) * 1979-05-07 1984-12-11 Kurt Rahlwes Tie-anchor for reinforcing cable
WO1985004456A1 (fr) * 1984-03-28 1985-10-10 Gerd Elger Accouplement lineaire
EP0327770B1 (fr) * 1988-02-03 1993-01-20 Etablissements A. Mure Procédé de réalisation de liaison mécanique de ronds à béton, rond à béton autorisant la mise en oeuvre du dit procédé et liaison mécanique de ronds à béton ainsi réalisée

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3850535A (en) * 1972-09-11 1974-11-26 Hewlett Machines Works Connecting means and method for forming reinforcing rod connection
ZA785370B (en) * 1978-09-21 1979-11-28 Boart Int Ltd Thread structure for percussion drill elements

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2255096A (en) * 1936-03-16 1941-09-09 B W Mfg Company Heading machine
US3333456A (en) * 1964-12-28 1967-08-01 Prescon Corp Machine for cold heading wire
US3415552A (en) * 1966-11-29 1968-12-10 Howlett Machine Works Splicing metallic reinforcing rods with a threaded coupling sleeve
US4237942A (en) * 1975-11-21 1980-12-09 Hans Dietrich Apparatus to produce an anchor on a tendon twisted of several steel wires
FR2435576A1 (fr) * 1978-09-07 1980-04-04 Lande Irving Procede et dispositif pour la jonction d'aboutement de barres d'armatures a beton
EP0017462A1 (fr) * 1979-04-05 1980-10-15 Geoffrey Arnold Snell Procédé pour la fabrication des articles en fil métallique
US4486991A (en) * 1979-05-07 1984-12-11 Kurt Rahlwes Tie-anchor for reinforcing cable
WO1985004456A1 (fr) * 1984-03-28 1985-10-10 Gerd Elger Accouplement lineaire
EP0327770B1 (fr) * 1988-02-03 1993-01-20 Etablissements A. Mure Procédé de réalisation de liaison mécanique de ronds à béton, rond à béton autorisant la mise en oeuvre du dit procédé et liaison mécanique de ronds à béton ainsi réalisée

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5308184A (en) * 1989-01-27 1994-05-03 Techniport S.A. Method and apparatus for mechanically joining concrete-reinforcing rods
EP0448488A1 (fr) * 1990-03-23 1991-09-25 Etablissements A. Mure Liaison mécanique de ronds à béton, manchon de liaison permettant la mise en oeuvre de la dite liaison et procédé de réalisation d'une telle liaison
FR2671365A1 (fr) * 1991-01-04 1992-07-10 Techniport Sa Liaison mecanique de ronds a beton, manchon de liaison permettant la mise en óoeuvre de la dite liaison, et procede de realisation d'une telle liaison.
EP0947642A3 (fr) * 1998-03-31 2000-01-12 Gyeng Ok Chung Procédé de réalisation d'une extrémité de jonction à une barre déformée pour béton armé, barre déformée réalisée au moyen de ce procédé et structure de jonction pour barre déformée
SG112795A1 (en) * 1998-03-31 2005-07-28 Gyeng Ok Chung Method of working connection end of deformed bar for reinforcing concrete, deformed bar worked by the method and structure of connecting deformed bar
EP1048798A1 (fr) * 1999-04-22 2000-11-02 Ancotech Ag Procédé de fabrication de fers à béton à filet extérieur

Also Published As

Publication number Publication date
AU4942690A (en) 1990-08-24
GB8901723D0 (en) 1989-03-15
GB2227802A (en) 1990-08-08

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