Hydraulic safety circuit

A hydraulic safety circuit for a hydraulic motor adapted to be driven from a source of pressurized hydraulic fluid, said circuit comprising:

• a inlet means associated with said motor for admitting said fluid to said motor to drive said motor, said fluid entering said motor being at a first pressure,
• b outlet means associated with said motor for removing said fluid from said motor, said fluid leaving said motor at said outlet means being at a second pressure, said first pressure being higher than said second pressure when said fluid is driving said motor, said second pressure being higher than said first pressure when said source is shut off and said motor is coasting,
• c first conduit means for conducting spent fluid from said outlet means,
• d second conduit means connecting said inlet means and said outlet means,
• e and check valve means associated with said first and second conduit means and responsive to said first and second pressures for directing fluid from said outlet means through said first conduit means when said fluid is driving said motor and said first pressure is higher than said second pressure and for directing fluid from said motor through said second conduit means and hence back to said inlet means of said motor when said second pressure is higher than said first pressure, whereby when said source is shut off to shut said motor off, and when said motor is coasting so that said second pressure is higher than said first pressure, said fluid may circulate through said motor, through said outlet means, through said check valve means, through said second conduit means back to said inlet means, and again through said motor, whereby to supply said motor with fluid during coasting and hence to reduce the likelihood of motor burnout during coasting.