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US 8,800,426 B2Granted
Hydraulic load control valve device
AssigneeNordhydraulic AB
InventorBo Andersson
Life of this patent
Estimating the term…
Abstract
A hydraulic load control valve (10) accommodated between a hand valve (H) and a hydraulic engine (D) has got at least one proportional load control valve (E), controlled by the pump pressure independent of the flow of hydraulic fluid to the engine. The flow to the engine (D) flows via a non-return valve (12), that is prestressed to open at a pump pressure above the upper limit before a given pressure interval, within which the load control valve (E) is adjusted between completely closed and completely open position of the pump pressure.
Claims15
A hydraulic load control valve device, comprising:
- a first engine connecting port (L′) and a second engine connecting port (N′) that are arranged to be connected to a first engine port (L) and a second engine port (N), respectively, on a double acting hydraulic cylinder (D);
- a first valve connecting port (M′) and a second valve connecting port (O′), which are arranged to be connected to separate operational ports (M and O, respectively) on a hand valve (H);
- a normally closed proportional load control valve (E), which has an inlet connected to the first engine connecting port (L′) and an outlet connected to the first valve connecting port (M′) and a control inlet that is hydraulically connected to the second valve connecting port (O′), said load control valve (E) arranged to vary between a closed position and a fully opened position as a pressure on the control inlet varies over a predetermined pressure interval;
- and
- a first check valve (12), an outlet side of said first check valve (12) connected to the second engine connecting port (N′) and an inlet side of said first check valve (12) connected to the second valve connecting port (O′), said first check valve (12) being pre-stressed or pre-stressable to open only when a pressure on the inlet side is higher than the predetermined pressure interval.
2 more elements
Dependencies are inferred from the claim text.