(19)
(11) EP 0 251 603 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
06.12.1989 Bulletin 1989/49

(43) Date of publication A2:
07.01.1988 Bulletin 1988/01

(21) Application number: 87305491.0

(22) Date of filing: 22.06.1987
(51) International Patent Classification (IPC)4: F15B 11/02, F15B 13/16
(84) Designated Contracting States:
AT BE CH DE ES FR GB GR IT LI LU NL SE

(30) Priority: 24.06.1986 GB 8615427

(71) Applicant: GROUP LOTUS PLC
Norwich Norfolk NR14 8EZ (GB)

(72) Inventors:
  • Williams, David Allen
    Cranfield Bedford (GB)
  • Wright, Peter Godfrey
    Norfolk, NR17 OSN (GB)

(74) Representative: Jones, Ian et al
G. RATHBONE & CO. High Holborn House 52-54 High Holborn
London WC1V 6RY
London WC1V 6RY (GB)


(56) References cited: : 
   
       


    (54) Hydraulic actuator controlled by servovalve


    (57) In an hydraulic system in which an hydraulic actuator (1) is controlled by a servovalve (10;50), a feed back signal derived from fluid flow associated with actuator movement is used to operate the servovalve, to ensure accurate control of the hydraulic actuator. The feedback signal can be an hydraulic signal derived from the pressure differential developed across a restriction (30) in the fluid flow, which can be applied to the servovalve directly, or an electrical signal for application to an electrical input to the servovalve, after modification if required, obtained from the pressure differential.







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