An air-driven hydraulic pump

Abstract

An air-driven hydraulic pump, comprising an air motor, and an oil pump, which is operatively connected with the air motor, wherein the air motor includes a cylinder element in which an air piston is arranged movable in a reciprocating manner along a centre axis. The air piston is connected with an oil piston of the oil pump for transmitting the reciprocating movement of the air piston to the oil piston. The air piston separates a first cylinder chamber from a second cylinder chamber within the cylinder element. A control valve element is arranged to control the application of pressurized air from a source of pressurized air to the cylinder element. At least one pressure control valve is arranged in the air motor, allowing an air flow from one of the cylinder chambers to the other cylinder chamber when the pressure difference between the two cylinder chambers exceeds a predetermined value.

1 - 15 . (canceled) 
     
     
         16 . An air-driven hydraulic pump, comprising an air motor, and an oil pump, which is operatively connected with the air motor, wherein the air motor comprises a cylinder element in which an air piston is arranged movable in a reciprocating manner along a centre axis, wherein the air piston is connected with an oil piston of the oil pump for transmitting the reciprocating movement of the air piston to the oil piston, wherein the air piston separates a first cylinder chamber from a second cylinder chamber within the cylinder element, wherein a control valve element is arranged to control an application of pressurized air from a source of pressurized air to the cylinder element, wherein at least one pressure control valve is arranged in the air motor, allowing an air flow from one of the cylinder chambers to the other cylinder chamber when a pressure difference between the two cylinder chambers exceeds a predetermined value. 
     
     
         17 . The air-driven hydraulic pump according to  claim 16 , wherein a single pressure control valve is arranged. 
     
     
         18 . The air-driven hydraulic pump according to  claim 16 , said at least one pressure control valve being arranged in the air piston. 
     
     
         19 . The air-driven hydraulic pump according to  claim 18 , said at least one pressure control valve penetrating the air piston in the direction of the centre axis. 
     
     
         20 . The air-driven hydraulic pump according to  claim 16 , said at least one pressure control valve being a check valve. 
     
     
         21 . The air-driven hydraulic pump according to  claim 20 , wherein the check valve comprises a housing in which a valve element is elastically biased against a seat by means of a spring element. 
     
     
         22 . The air-driven hydraulic pump according to  claim 21 , wherein the valve element is a ball. 
     
     
         23 . The air-driven hydraulic pump according to  claim 21 , wherein the spring element is a helical spring. 
     
     
         24 . The air-driven hydraulic pump according to  claim 21 , wherein the housing has a substantially hollow cylindrical form. 
     
     
         25 . The air-driven hydraulic pump according to  claim 24 , wherein an axis of the housing is parallel to the centre axis of the cylinder element. 
     
     
         26 . The air-driven hydraulic pump according to  claim 25 , wherein the axis of the housing and the centre axis of the cylinder element are radially distanced from each other. 
     
     
         27 . The air-driven hydraulic pump according to  claim 16 , said at least one pressure control valve comprising means for adjusting the pressure difference between the two cylinder chambers at which the at least one pressure control valve opens. 
     
     
         28 . The air-driven hydraulic pump according to  claim 27 , said means for adjusting the pressure difference comprising a screw element which is screwed into a thread in the housing. 
     
     
         29 . The air-driven hydraulic pump according to  claim 28 , wherein the screw element has a hexagon socket at one of its face sides. 
     
     
         30 . The air-driven hydraulic pump according to  claim 16 , wherein the air piston and the oil piston are arranged coaxially. 
     
     
         31 . The air-driven hydraulic pump according to  claim 18 , said at least one pressure control valve being a check valve. 
     
     
         32 . The air-driven hydraulic pump according to  claim 18 , said at least one pressure control valve comprising means for adjusting the pressure difference between the two cylinder chambers at which the at least one pressure control valve opens. 
     
     
         33 . The air-driven hydraulic pump according to  claim 18 , wherein the air piston and the oil piston are arranged coaxially. 
     
     
         34 . The air-driven hydraulic pump according to  claim 19 , wherein the air piston and the oil piston are arranged coaxially.