EP0101268A2 - Spannpresse für vorgespannte Konstruktionen - Google Patents

Spannpresse für vorgespannte Konstruktionen Download PDF

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Publication number
EP0101268A2
EP0101268A2 EP83304537A EP83304537A EP0101268A2 EP 0101268 A2 EP0101268 A2 EP 0101268A2 EP 83304537 A EP83304537 A EP 83304537A EP 83304537 A EP83304537 A EP 83304537A EP 0101268 A2 EP0101268 A2 EP 0101268A2
Authority
EP
European Patent Office
Prior art keywords
stressing
jack
casing
cylinder
pulling cylinder
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP83304537A
Other languages
English (en)
French (fr)
Other versions
EP0101268A3 (de
Inventor
Michael Arthur Smith
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CCL Systems Ltd
Original Assignee
CCL Systems Ltd
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 CCL Systems Ltd filed Critical CCL Systems Ltd
Publication of EP0101268A2 publication Critical patent/EP0101268A2/de
Publication of EP0101268A3 publication Critical patent/EP0101268A3/de
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
    • E04G21/12—Mounting of reinforcing inserts; Prestressing
    • E04G21/121—Construction of stressing jacks

Definitions

  • the invention relates to the prestressing of concrete structures and in particular to a jack for use in stressing the elements, eg. wires, strands, cables, of the tendon in a prestressed concrete structure.
  • a jack for use in stressing the elements, eg. wires, strands, cables, of the tendon in a prestressed concrete structure.
  • Such jacks are well known see eg. our British patents 1066713 and 1375203 (Agents ref:7097 and 7141 respectively).
  • a stressing jack for use in stressing a plurality of elongate stressing elements for a concrete structure, the jack comprising a main casing including a forward nose portion adapted to bear on one end face of the concrete structure, a pulling cylinder within the casing and arranged to move axially of the casing and pull the elements towards the rearward end of the casing, lock off means arranged to operate with the pulling cylinder, and pulling cylinder, and limiting means to reduce the axial tension generated in the rearward end of the casing at or towards the limit of the rearward movement of the pulling cylinder.
  • the limiting means comprises a shuttle valve.
  • the valve is arranged to be opened by mechanically contacting an end plate at the limit of the rearward movement of the pulling cylinder.
  • the valve preferably includes a projecting plunger.
  • the stressing jack comprises a main casing having a thrust plate from a forward end of which extends a lock off assembly and a forward nose portion adapted to bear on an end face of the concrete structure, a pulling cylinder disposed-within the casing and in engagement with a piston disposed rearwardly of the thrust plate, the cylinder being arranged to move axially of the casing and pull the elements towards the rearward end of the casing, a source of pressurised fluid for moving the pulling cylinder and actuating the lock off assembly, and limiting means in association with the pressurised fluid acting on the thrust plate to reduce the axial tension generated in the rearward end of the casing at or towards the limit of the rearward movement of the pulling cylinder.
  • Figure 3 is a rear end view of the jack
  • the jack of Figures 1 to 3 comprises a main casing having an outer cylinder 1.
  • a thrust plate 2 is connectable by a thread connection to the forward end of the cylinder 1 and from the front of the thrust plate 2 extends a lock off assembly comprising a lock off cylinder 3, a lock off piston 4 and a lock off thrust plate 26.
  • a nose portion 5 extends forwardly of the lock off assembly and is adapted to engage a bearing plate 6 which engages an anchorage A of a concrete structure, Figure 2.
  • a piston cylinder 7 is present in the outer cylinder rearwardly of the thrust plate 2.
  • the inner cylinder 8 houses a nest of tubes 11 corresponding in shape and -number to the strands or wires of the anchorage element A.
  • the tubes are held at their forwards ends in a forward locating ring 23.
  • a set of gripping wedges 12 is present in a rear gripping plate 13 to engage the strands or wires and the plate 13 is connected to the piston head by clamps 14.
  • the tubes 11 also locate in the rear gripping plate 13 so that rotation of the plate 13 also rotates the tubes 11.
  • the tubes 11 and the plate 13 are free to-rotate with respect to the cylinder 8.
  • the plate 13 has handles 25 so that it may easily be mounted in the jack.
  • a retract cylinder 15 extends from the piston head 7 and the movement thereof is restricted by an end plate 16 depending from the rearward end of the outer cylinder 1.
  • the jack includes a supply of hydraulic fluid, not shown. Pressurised fluid may be admitted via inlet 17 and exit via outlet 18 to move an assembly of the piston head 7, inner cylinder 8 and retract cylinder 15 rearwardly.
  • a safety pressure limiting shuttle valve 19 is present in the path of the pressurised fluid through the piston head 7 and serves to direct the fluid back to the reservoir when a pressure limit has been reached, so avoiding the generation of axial tension in the outer cylinder 1.
  • Two bands 20 pass about the outer cylinder 1 and have lifting hooks 21 so that the jack may be moved as required.
  • the bands are rotatable so that the hoses carrying the pressure fluid to and from the jack can be -positioned anywhere on a circumference of 360 relative to the lifting points.
  • the parts of the jack are assembled by threading the thrust plate 7 into the forward end of the outer casing 1, and the hydraulic lines are connected.
  • the jack is advanced to a concrete body to be stressed and the ends of the wires or strands are then fed through the lock off thrust plate 26 and into the tubes 11.
  • the wedges 12 are engaged with the wire or strand ends.
  • Pressurised fluid is then admitted to urge the piston head 7 to the rear so stressing the wires or strands.
  • Rearward movement of the piston head 7 cannot go past the end plate 16 and when the piston head approaches the end plate the valve 19 opens so directing fluid to the reservoir and preventing axial tension being generated in the outer cylinder 1.
  • the valve 19 communicates between the extend side of piston cylinder 7, and the retract side.
  • the shuttle valve has a plunger 22 which projects from the retract side of the piston cylinder.
  • the plunger 22 strikes the end plate 16 which opens the shuttle valve 7, and. allows oil to pass from the extend side of the piston cylinder into the retract chamber on the retract side of the piston cylinder, and then back to the tank through the retract hose.
  • valve 19 When there is no load in the jack then the valve 19 is opened fully, the pressure created across it being very small, and hence the axial load generated in the outer cylinder is negligible.
  • valve 19 When the jack reaches full extension and is also loaded the valve 19 will not open far enough for the pressure in the extend side of the piston to be eliminated, as this would allow the jack to retract, the valve closing again immediately.
  • the valve is arranged to open just sufficiently to take the full flow of hydraulic oil from the pump, but with a pressure generated across the valve just sufficient to maintain load in the stressing elements. This means that the force in the jack is balanced exactly by the force in the stressing elements, and negligible force is transmitted into the end plate or outer cylinder.
  • the flow of oil from the retract side to the extend side of the piston cylinder closes the valve (in the opposite direction to the extend operation) and the jack retracts.
  • the lock off system is energised either at full stroke or at a predetermined load. Pressurised fluid closes the shuttle valve and acts to retract the inner cylinder, in known manner. The strands or wires are then held in position against the bearing plate 6 by the wedges W and excess lengths are cut off.

Landscapes

  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Mechanical Engineering (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • On-Site Construction Work That Accompanies The Preparation And Application Of Concrete (AREA)
  • Actuator (AREA)
EP83304537A 1982-08-07 1983-08-05 Spannpresse für vorgespannte Konstruktionen Withdrawn EP0101268A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8222830 1982-08-07
GB8222830 1982-08-07

Publications (2)

Publication Number Publication Date
EP0101268A2 true EP0101268A2 (de) 1984-02-22
EP0101268A3 EP0101268A3 (de) 1985-11-27

Family

ID=10532185

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83304537A Withdrawn EP0101268A3 (de) 1982-08-07 1983-08-05 Spannpresse für vorgespannte Konstruktionen

Country Status (4)

Country Link
EP (1) EP0101268A3 (de)
AU (1) AU551307B2 (de)
IN (1) IN160947B (de)
ZA (1) ZA835495B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2589536A1 (fr) * 1985-11-04 1987-05-07 Framatome Sa Dispositif de tension pour le serrage et le desserrage de boulons ou goujons
ES2084538A2 (es) * 1992-10-14 1996-05-01 Mekano 4 S A Gato hidraulico para tesar tendones de hormigon pretensado.
CN101798876A (zh) * 2010-04-28 2010-08-11 赵正义 退张前减小钢筋应力的构造

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1243980B (de) * 1964-07-11 1967-07-06 Frieseke & Hoepfner Gmbh Hydraulische Hubeinrichtung mit hydraulischem Kolbenrueckzug
US3338552A (en) * 1965-04-23 1967-08-29 Christiani & Nielsen Ltd Hydraulic jacks and the like
DE7012963U (de) * 1970-04-09 1970-07-30 J P Sauer & Sohn Maschb Gmbh Vorrichtung zum vermeiden von unzulaessigen druckdifferenzen in druckmittelzylindern.
DE2308216A1 (de) * 1973-02-20 1974-08-29 Max Paul & Soehne Maschf Spannpresse zum gleichzeitigen spannen einer gruppe zugstraenge in vorgespannten konstruktionen
US4106752A (en) * 1976-05-04 1978-08-15 Buildinter Ag Jack for stressing concrete re-inforcement elements

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1243980B (de) * 1964-07-11 1967-07-06 Frieseke & Hoepfner Gmbh Hydraulische Hubeinrichtung mit hydraulischem Kolbenrueckzug
US3338552A (en) * 1965-04-23 1967-08-29 Christiani & Nielsen Ltd Hydraulic jacks and the like
DE7012963U (de) * 1970-04-09 1970-07-30 J P Sauer & Sohn Maschb Gmbh Vorrichtung zum vermeiden von unzulaessigen druckdifferenzen in druckmittelzylindern.
DE2308216A1 (de) * 1973-02-20 1974-08-29 Max Paul & Soehne Maschf Spannpresse zum gleichzeitigen spannen einer gruppe zugstraenge in vorgespannten konstruktionen
US4106752A (en) * 1976-05-04 1978-08-15 Buildinter Ag Jack for stressing concrete re-inforcement elements

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2589536A1 (fr) * 1985-11-04 1987-05-07 Framatome Sa Dispositif de tension pour le serrage et le desserrage de boulons ou goujons
EP0222625A1 (de) * 1985-11-04 1987-05-20 Framatome Spannvorrichtung zum Schrauben und Entschrauben von Bolzen oder Stiften
US4802806A (en) * 1985-11-04 1989-02-07 Framatome Tension device for tightening and loosening bolts or pins
ES2084538A2 (es) * 1992-10-14 1996-05-01 Mekano 4 S A Gato hidraulico para tesar tendones de hormigon pretensado.
CN101798876A (zh) * 2010-04-28 2010-08-11 赵正义 退张前减小钢筋应力的构造
CN101798876B (zh) * 2010-04-28 2012-09-12 赵正义 退张前减小钢筋应力的构造

Also Published As

Publication number Publication date
IN160947B (de) 1987-08-15
AU1758083A (en) 1984-02-09
EP0101268A3 (de) 1985-11-27
ZA835495B (en) 1984-09-26
AU551307B2 (en) 1986-04-24

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Inventor name: SMITH, MICHAEL ARTHUR