Control for deflection reduction means

Claim 2

In a vehicle across terrain: a chassis vertically deflectable relative to said terrain; a load-handling boom pivotally mounted on said chassis and vertically deflectable relative to said chassis; a boom-hoist cylinder for raising and lowering said boom; a source of hydraulic fluid for operating said hoist cylinder boom; deflection reduction means, including a spring, and a volume of compressible gas and a gas piston, connected between said boom and said chassis and operable to reduce deflection of said chassis relative to said terrain as said vehicle moves thereacross; and a control system including valve means operable to connect said boom-hoist cylinder to said source in order to effect boom-hoist operations of said boom, said valve means being further operable to connect said boom-hoist cylinder to said deflection reduction means so that deflection of said boom causes said boom-hoist cylinder to operate to impose or relieve forces acting on said spring and said volume of compressible gas in said deflection reduction means.

Claim 3

A vehicle according to claim 1 wherein said boom-hoist cylinder comprises a boom-hoist piston and hydraulic fluid chambers on opposite sides of said piston, wherein said valve means in said control system includes a selectively operable three-way valve operable to raise and lower said boom, a holding valve operable to maintain said boom in a raised position, and selectively operable valve means to by-pass said three-way valve and to connect said hydraulic fluid chambers to each other so that fluid-flow between said chambers effected by movement of said boom-hoist piston in response to deflection of said boom effects movement of said gas piston which is associated with said spring and said volume of compressible gas.

Claim 4

A vehicle according to claim 2 wherein said boom-hoist piston has a larger area than said gas piston.

Claim 5

A vehicle according to claim 3 wherein one side of said gas piston is in communication with one of said hydraulic fluid chambers of said boom-hoist cylinder at least when said chambers are connected to each other.

Claim 6

A vehicle according to claim 4 wherein said one side of said gas piston is in communication with one of said hydraulic fluid chambers regardless of the operative condition of said selectively operable valve.

Claim 7

A vehicle according to claim 2 wherein said selectively operable valve means of said control system comprises a solenoid-operated valve having one position wherein it operates as a check valve and maintains said three-way valve in circuit and able to effect hoisting operation of said boom, and another position wherein it by-passes said three-way valve.

Claim 8

In a vehicle (10) movable across terrain (T) and comprising: a vehicle chassis (18) capable of reciprocable vertical and angular deflection relative to said terrain (T) as said vehicle (10) moves thereacross; load-handling a boom component (12) carried by said chassis (18) and capable of reciprocable vertical angular deflection relative to said chassis (18) as said vehicle (10) moves across said terrain (T); a lift cylinder connected between said chassis and said load-handling boom component and selectively operable to vertically move said load-handling boom component relative to said chassis, said lift cylinder comprising an outer cylinder having a main bore, a main piston slidably mounted in said main bore and dividing said main bore into two chambers, a piston rod connected to said main piston and extending from an end of said outer cylinder, means for supplying hydraulic fluid from a source to said lift cylinder; deflection reduction means connected between said chassis (18) and said load-handling boom component (12) to reduce said deflection of said chassis (18) relative to said terrain (T); said deflection reduction means including resiliently compressible and expandable load-bearing spring means (60) connected between said chassis (18) and said load-handling boom component (12) and damping means (62) connected between said chassis (18) and said load-handling boom component (12) and to said spring means (60), said damping means comprising a chamber containing pressurized compressible gas; and a control system including valve means selectively operable to conduct hydraulic fluid between said chambers and said source to operate said lift cylinder to raise and lower said boom; and to connect said chambers of said lift cylinder to raise and lower said boom; and to connect said chambers of said lift cylinder to each other so that motion of said main piston effected by deflection of said load-handling boom effects hydraulic fluid flow to thereby apply or relieve forces acting on said spring means and said damping means.

Claim 9

In a vehicle (10) movable across terrain (T) and comprising: a vehicle chassis (18) capable of reciprocable vertical and angular deflection relative to said terrain (T) as said vehicle (10) moves thereacross; load-handling a boom component (12) carried by said chassis (18) and capable of reciprocable vertical angular deflection relative to said chassis (18) as said vehicle (10) moves across said terrain (T); a lift cylinder connected between said chassis and said load-handling boom component and selectively operable to vertically move said load-handling boom component relative to said chassis, said lift cylinder comprising an outer cylinder having a main bore, a main piston slidably mounted in said main bore and dividing said main bore into two chambers, a piston rod connected to said main piston and extending from an end of said outer cylinder, means for supplying hydraulic fluid from a source to said lift cylinder; deflection reduction means connected between said chassis (18) and said load-handling boom component (12) to reduce said deflection of said chassis (18) relative to said terrain (T); said deflection reduction means including resiliently compressible and expandable load-bearing spring means (60) connected between said chassis (18) and said load-handling boom component (12) and damping means (62) connected between said chassis (18) and said load-handling boom component (12) and to said spring means (60), said damping means comprising a chamber containing pressurized compressible gas; and a control system including valve means selectively operable to conduct hydraulic fluid between said chambers and said source to operate said lift cylinder to raise and lower said boom; and to connect said chambers of said lift cylinder to raise and lower said boom; and to connect said chambers of said lift cylinder to each other so that motion of said main piston effected by deflection of said load-handling boom effects hydraulic fluid flow to thereby apply or relieve forces acting on said spring means and said damping means.

Claim 10

A vehicle according to claim 7 wherein said deflection reduction means comprises a secondary bore in said piston rod, a secondary piston slidably mounted in said secondary bore and dividing said secondary bore into two chambers, said load-bearing spring means being located in said secondary bore for biasing said secondary piston in a predetermined direction, and a passage communicating between one of said chambers in said main bore and one of said chambers in said secondary bore for admitting fluid to said last-recited chamber to act against the bias of said biasing means.

Claim 11

A vehicle according to claim 7 wherein said pressurized compressible gas is entrapped in the other of said chambers in said secondary bore.