Patent ID: 8316757

Claim:
A hydraulic valve assembly ( 1 ), comprising: a monolithic valve body ( 5 ) formed of a single piece, the body having a top face ( 7 ) and a bottom face ( 9 ) and four sides ( 11 , 13 , 15 , 17 ) extending between the top and bottom faces ( 7 , 9 ), the four sides defining a front side ( 11 ), a left side ( 13 ), a rear side ( 15 ), and a right side ( 17 ); plural valve bores ( 21 , 23 , 25 ) extending between the front side and the rear side of the valve body; a hydraulic supply inlet ( 27 ) and a discharge tank outlet ( 29 ) located on the left and right sides of the valve body and in fluid communication with the valve bores ( 21 , 23 , 25 ); plural work port pairs ( 31 , 32 ; 33 , 34 ; 35 , 36 ), each work port pair having an opening at the top face and extending to a different one of the valve bores, each work port pair comprising a first work port ( 31 , 33 , 35 ) and a second work port ( 32 , 34 , 36 ); plural pilot port pairs ( 41 , 42 ; 43 , 44 ; 45 , 46 ), all pilot port pairs located on the front side, each pilot port pair having an opening at the front side and extending to ends of a different one of the valve bores; plural control spools ( 51 , 52 , 53 ), one of the control spools in each of the valve bores, each control spool being moveable to control flow of hydraulic fluid between each work port and the inlet and the outlet, wherein, there are three valve bores, three work port pairs, three pilot port pairs, and three control spools that define three separately operable valves ( 81 , 82 , 83 ), one of the control spools being a lift spool ( 53 ), the two other control spools being a tilt spool ( 52 ) and an auxiliary spool ( 51 ), a positioner spring ( 71 , 72 ; 73 , 74 ; 75 , 76 ) located at each end of all of the three control spools; and a single port lock spool ( 61 ) located in fluid flow intermediate the openings of the first work ports ( 31 , 33 , 35 ) and the valve bores, the port lock spool being moveable and operatively connected to operate as an ON-OFF valve to lock at least two of the first work ports at the same time, wherein, with the first work ports locked close, fluid flow is prevented to the corresponding valve bores.