Auxiliary brake system for outdoor grounds maintenance vehicles having hydrostatic traction drive systems

An outdoor grounds maintenance vehicle, which comprises:

• (a) a frame supported for movement over a ground or turf surface by a plurality of ground engaging wheels, the frame carrying a prime mover, a throttle for establishing a rotational speed of the prime mover, a seat for an operator, and an implement for performing a grooming or working operation on the ground or turf surface;
• (b) a hydrostatic traction drive system powered by the prime mover and operatively coupled to at least one wheel for self-propulsion of the frame over the ground or turf surface, the drive system providing hydrostatic dynamic braking for slowing or stopping the frame during operation of the vehicle;
• and
• (c) an auxiliary brake system having a prime mover kill device that is separate from the throttle and that provides graduated control by the operator of the rotational speed of the prime mover to reduce the rotational speed of the prime mover from a predetermined value as established by the throttle;
• and
• (d) a parking brake system that is separate from the auxiliary brake system, wherein the parking brake system and the auxiliary brake system can be activated independently of each other.