Eaton Corporation

The Toro Company

John B Heckel

Marvin L Bernstrom

Rex R Bergsten

Wayne B Wenker

Michael W Barto

David H Torborg

Matthew J Decker

Luke R Nahorniak

Mark D Schuster

An outdoor grounds maintenance vehicle is self-propelled by a hydrostatic traction drive system that provides dynamic braking to the vehicle without the need for separate service brakes acting on the wheels of the vehicle. An engine kill device can be manually actuated by the operator to access the dynamic braking of the traction drive system by reducing the speed of the prime mover that powers the pump of the traction drive system. This provides an auxiliary braking system that can be used in an emergency or on demand by the operator in the event the accelerator pedal does not properly control the pump swashplates. The operator can control the rate at which the auxiliary brake system reduces the speed of the prime mover to zero.

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

A mower having a cutting deck for cutting grass has four drive wheels arranged in a square or rectangular configuration on the mower's frame. Four wheel drive and four wheel steering are employed with the drive wheels. The four wheel drive is provided by a hydraulic drive system that employs a pair of identical serial circuits which have their own pumps with each pump serially sending its output through a rear drive motor and a front drive motor that are catty-corner to one another on the frame, i.e. are on opposite sides of the motor. Various flow crossover paths and flow recirculation paths are provided in the serial circuits to ensure the drive motors receive adequate flow in maximum turns of the mower. The flow recirculation paths around a pair of drive motors at one end of the frame are shut off during reverse and during braking so that all drive motors retain hydraulic braking in these conditions.

Mower with four wheel steering and hydraulic four wheel drive

A two-speed gerotor motor ( ) including motor valve means ( ) to communicate fluid to and from expanding ( E) and contracting ( ) fluid volume chambers. The motor includes a shift valve spool ( ) to cause the motor to operate either in the normal, low-speed, high-torque (LSHT) mode (FIG. ) or in a high-speed, low-torque (HSLT) mode (FIG. ). When the motor operates in HSLT mode, certain of the volume chambers comprise recirculating volume chambers ( R). The motor ( ) defines a supplemental fluid passage ( ) through which fluid is communicated from a system charge pump ( ) to each of the recirculating volume chambers ( R). A control valve ( ) is operable, in a shift mode (S) to permit fluid communication from the charge pump ( ) to the supplemental fluid passage ( ), thus preventing cavitation during shifting of the motor ( ), especially when shifting from the HSLT mode to the LSHT mode.

Anti cavitation system for two-speed motors

A multiple speed ratio gerotor motor having first ( ) and second ( ) gerotor gear sets as the displacement mechanisms, and a commutating valve member ( ) of the well known type. In one embodiment (FIGS. ) there is provided a selector valve section ( ) disposed between the first and second gerotor gear sets, and in a low speed mode (FIG. A), fluid flows from the commutating valve member ( ) through the first volume chambers ( ), then through the selector valve section, then through the second volume chambers ( ). In a high speed mode (FIG. B), flow out of the first volume chambers ( ) is blocked by the selector valve section ( ), and fluid in the second volume chambers ( ) flows through the selector valve section to the case drain region ( ). In a free wheel mode (FIG. C), both the first and second volume chambers are open to case drain. In another embodiment (FIG. ), the selector valve section ( ) is disposed between the commutating valve member ( ) and the first gerotor gear set ( ), and can permit, or block, fluid communication to either gerotor gear set separately, thus providing three speed capability. In either embodiment, the relative speed ratios which can be achieved are determined by the relative axial lengths of the two gerotor gear sets, thus providing much greater flexibility in the choice of high-speed, low-torque speed ratios.

Hydraulic motor having multiple speed ratio capability

A brake assembly of the type in which there are provided brake discs (,) which are pressed into frictional engagement by a lock piston (,). The lock piston is of the type applied by a set of Belleville washers (,) and released by fluid pressure in a chamber (,). The invention provides a disengagement mechanism (,) associated with the lock piston (,) and including a manually operable handle (,) disposed external to a housing (,) enclosing the brake assembly. The handle is moveable between a normal position (FIG.,) and a disengagement position (FIG.,) in which the lock piston is moved toward at least a partially retracted position, in opposition to the force of the Belleville washers. When pressurized fluid is again communicated to the chamber (,), the lock piston is biased to its fully retracted position, and the handle (,) of the disengagement mechanism (,) returns to its normal position (FIG.,), ready for the next time the operator wants to manually disengage the brakes.

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Shakopee, MN, United States of America

John B Heckel