Automatic adjuster for vehicle headlamp - aims headlamp relative to vehicle load using hydromechanical actuator in which oil pressure acts on conical piston surface

摘要

The automatic adjuster for headlamp aiming derives its operating power from a hydraulic pressure cell responsive to vehicle load. A pipe (80) connects the cell to a sealed cylinder (68, 81) which contains the piston (61) which also forms part of the mechanical adjuster for giving the initial headlamp aiming. The piston is enclosed in an elastically deformable sheath (73) impervious to oil. On the piston rod is a conical section (62) against which the variation in hydraulic pressure acts. The operating end of the piston (59) is attached to the hinged headlamp reflector (79), and also to a reset spring (66). As the vehicle load increases the hydraulic pressure in the cylinder drops, and the reset spring acts to aim the reflector downwards. On reducing the load the increased pressure moves the piston against the spring. The construction requires little space.