Hydraulic vibrator for actuator drive

A hydraulic vibrator for the drive of actuators in metal-cutting machines, comprising:

• a casing;
• a differential piston arranged in said casing and moving reciprocally therein, said differential piston having a first pressure surface and a second pressure surface, the second pressure surface of the piston being larger than the first pressure surface;
• a spring-balanced slide valve having a plurality of plungers which are arranged coaxially in said differential piston and which move reciprocally therein;
• said differential piston and said casing being positioned so that they define at least one inlet chamber, one pressurized chamber and one discharge chamber, said inlet chamber being defined at least partially by the first pressure surface of said piston and by said casing, said pressurized chamber being defined by the second pressure surface of said piston and at least partially by said casing, and said discharge chamber being defined at least partially by said casing and by an end of said piston;
• said spring-balanced slide valve ensuring successive communication of said pressurized chamber with said discharge and inlet chambers;
• said slide valve defines by its plungers, together with said piston, a plurality of compensating chambers;
• throttles of constant section providing communication between said inlet chamber and said compensating chambers, said throttles of constant section ensuring a drop in the pressure, as a result of which the pressure in the compensating chambers is less than the pressure in the inlet chamber;
• and throttles of variable section controlling communication between the compensating chambers and said discharge chamber;
• whereby said differential piston performs reciprocating displacements smoothly and noiselessly.