Jack for prestressed concrete structure

(19)

(11)

EP 0 101 268 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	27.11.1985 Bulletin 1985/48

(43)	Date of publication A2:
	22.02.1984 Bulletin 1984/08

(21)	Application number: 83304537

(22)	Date of filing: 05.08.1983

(84)	Designated Contracting States:
	AT BE DE FR GB IT NL

(30)

Priority:

07.08.1982 GB 8222830

(71)	Applicant: CCL SYSTEMS LIMITED
	()

(72)	Inventor:
	Smith, Michael Arthur ()

(54)	Jack for prestressed concrete structure

(57) A stressing jack is of light weight because limiting means (19) are provided to reduce the axial tension generated in the rearward end of the jack casing (1) at or towards the limit of the rearward movement of the jack pulling cylinder (8).
Preferably the limiting means is a safety pressure limiting shuttle valve (19) having a plunger (22). Because of the limiting means the outer cylinder wall can be of low thickness which saves weight and creates stability.

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