A piston assembly for hydraulically operated piston-type retarders

(19)

(11)

EP 0 752 357 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	05.11.1997 Bulletin 1997/45

(43)	Date of publication A2:
	08.01.1997 Bulletin 1997/02

(21)	Application number: 96304982.0

(22)	Date of filing: 05.07.1996

(51)	International Patent Classification (IPC)⁶: B61K 7/02

(84)	Designated Contracting States:
	AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

(30)

Priority:

05.07.1995 ZA 9505575

(71)	Applicant: TRANSNET LIMITED
	Parktown (ZA)

(72)	Inventor:
	van Heerden,Andre Jacques Johannesburg 2000 (ZA)

(74)	Representative: Godwin, Edgar James
	MARKS & CLERK, 57-60 Lincoln's Inn Fields London WC2A 3LS London WC2A 3LS (GB)

(54)	A piston assembly for hydraulically operated piston-type retarders

(57) The invention relates to a piston assembly for use in a hydraulically operated piston-type retarder. The piston assembly comprises a piston rod 1, a piston head 2, a speed spring 3, a closure member 4, a spacer member 5, a retainer member 9 and a lock nut 6. The piston head 2 is provided with a set of first hydraulic fluid passageways with corresponding energy extraction ports 8 and a set of second hydraulic fluid passageways with corresponding idling ports 7. A method of retarding wagon stock is also provided.

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