CRANE LOAD WINCH BRAKE CONTROL VALVE Russian patent published in 2000 - IPC

FIELD: mechanical engineering; materials handling facilities; hydraulic cranes. SUBSTANCE: valve has housing with two central ring grooves, two extreme grooves and two holes, one of which serves for connecting valve with brake hydraulic cylinder, and the other, for connecting valve with return hydraulic line of crane hydraulic system. Crane has spool with shank and pull-back spring, and two covers with holes for connecting valve with hydraulic line of load winch hydraulic motor. Central ring groove made on spool interconnects two central grooves of housing when spool is in neutral position. One of housing central grooves is connected by channels with first hole, and the other, with second hole. Spool can be provided with two extreme ring grooves connected by channels in spool and shank with holes in covers. It is expedient to connect extreme ring grooves made in housing with hole designed for connecting valve to brake hydraulic cylinder. EFFECT: provision of required braking margin coefficient and reliable operation of crane load winch brake under various operating conditions. 3 cl, 1 dwg