Abstract: The present invention relates to an automatic gear box and a control therefor of a motor vehicle, including two pulleys connected by a transmission belt (driving belt), each of which is formed by a couple of disks, of which one is movable in regard to the other one, in order to vary the winding radius of the belt. The control for the automatic gear box includes an hydraulic circuit which incorporates a number of actuating cylinders, a couple of delaying valves and a valve for issuing a fluid gradually and under increasing pressure only if the inlet pressure is above a preestablished value.

Abstract: The valve is arranged to control the pressure of a hydraulic fluid by discharging a proportion of its flow, and comprises a mobile valve element arranged to control the opening of a discharge port of a first chamber and kept normally closed by the action of a spring, a piston element rigid with said valve element and arranged to define a second chamber which is in hydraulic communication with the first by way of a first bore of predetermined size, and a third chamber in hydraulic communication both with the preceding by way of a second bore also of predetermined size, and with the discharge outlet by way of a discharge port the opening of which is controlled by an interception member operated by an electromagnet; the pressure of said fluid is controlled by varying the discharge port controlled by said interception member and consequently the rate of a flow of control fluid passing through said first bore, second chamber, second bore and third chamber.

Abstract: The valve of the invention is provided with a movable slide valve operable to open a first flow passage between a supply duct, which connects a source of fluid under pressure with the valve, and a utilization duct, which connects the valve itself with the utilizer, and a second flow passage between this utilization duct and a discharge duct; the slide valve is in equilibrium between a resilient force generated by a spring which acts on it and the force, in the opposite direction, generated by the fluid pressure which is supplied to a control chamber and the discharge flow cross section of which is controlled by a valve member operated by an electromagnet.

Abstract: The distributor is designed to control the supply of a fluid under pressure into a chamber of a hydraulic actuator and the outlet of fluid from another chamber of said actuator, and comprises a first chamber and a second chamber, which are designed to be communicated with one of said chambers of the actuator, and a slide valve movable in the direction of its axis in a corresponding seat of the distributor; the distributor comprises means which respond to the pressure prevailing inside said first and second chambers of the distributor and means for choking the cross-section of the outlet for the fluid from said first and second chambers of the distributor, said pressure-responsive means being connected to said choking means so that, as a result of a movement of the movable member of said actuator at a velocity higher than a predetermined velocity, said choking means bring about a reduction in the velocity of said movable body.

Abstract: The regulator is designed to control the flow of a pressurized fluid between a source of said fluid which feeds it at a feed pressure, and a user device in which the fluid is at a utilization pressure which depends on the operating conditions of the device; the regulator also comprises a valve element mobile in the direction of its axis and arranged to vary the degree of closure of an orifice between a feed chamber and a utilization chamber, and a first and second cavity in which there is housed a first and second active surface respectively, on one of which there acts the utilization pressure and on the other of which there acts a control pressure arranged to control the movement of the valve element.

Abstract: A suspension system for motor vehicles of the type designed to maintain automatically the horizontal attitude of a motor vehicle with variations in loads on the front suspensions and on the rear suspensions comprises two hydraulic cylinders interposed between the springs of the rear suspensions and the suspended masses in correspondence with the rear axle of the motor vehicle. Each hydraulic cylinder incorporates a distribution valve comprising a slide valve subject at one of its ends to the pressure within the hydraulic cylinder and its opposite end to the pressure transmitted by a hydraulic pump by means of a control valve which is responsive to the subsidence of the front suspensions.

Abstract: A fluid control device for the selective control of at least one group of three movable members each displaceable between a first working position and a second working position, and each having a rest position intermediate between the first and the second working position includes, for each group of three movable members, a group of three hydraulic control units, each control unit being intended to control a respective movable member, and control means for controlling the feeding of a fluid under pressure coming from a feed source to each of the three feed ducts of each group of three control units.