Hydraulically-operated anti-skid vehicle braking system with pump

An hydraulically-operated anti-skid braking system for a vehicle comprising a brake for braking the wheel of the vehicle, a reservoir for hydraulic fluid, a pump for providing a supply of hydraulic fluid under pressure from said reservoir, first control means through which hydraulic fluid is delivered by said pump, an outlet port, said first control means including a first orifice through which fluid from said pump is passed to provide a pressure in response to which said brake is adapted to be applied by means of hydraulic fluid being delivered through said outlet port, an inlet port, second control means, and a master cylinder by means of which hydraulic fluid pressure is applied to said second control means through said inlet port, said second control means controlling operation of said pump in response to hydraulic fluid pressure applied to said second control means, wherein said pump is rotatable with rotation of said wheel to be braked whereby said wheel is automatically prevented from locking, and wherein said pump has substantially constant output flow at least throughout a wheelspeed range above a predetermined minimum.