(57) Proportioners may be used in hydraulic circuits to provide the symmetrical deployment
of components controlled by these circuits. In the airbrake-deploying circuit of an
aircraft, for example, certain fail-safe conditions must be satisfied i.e. the symmetrical
deployment of the airbraking surfaces, and therefore the inclusion of a proportioner
is desirable if not essential. The invention described herein relates to a proportioner
having twin fluid flow path which incorporates a stepper motor, the stepper motor
being operable to adjust the flow in each flow path via throttling means so that the
airbrakes, for example, are deployed synchronously. The proportioner is also inherently
fail-safe, as the pressure differential in the two fluid flow path acts to cancel
any imbalance which may be present in the hydraulic circuit should the stepper motor
fail.
|
|
