Pressure cylinder with oil storing function

Abstract

A pressure cylinder includes a first cylinder body having accommodated therein a piston. a second cylinder body defining therein a first passage vertically connected to the first cylinder body, an oil storage chamber vertically connected to the first passage, a second passage vertically connected to the oil storage chamber and a pressure chamber vertically connected to the second passage and having a cross-sectional area smaller than the oil storage chamber, and a piston rod inserted through the first passage of the second cylinder body in an airtight manner and having its one end connected to the piston and its other end movable by the piston between a first position in the oil storage chamber and a second position in the pressure chamber to add a pressure to the hydraulic oil in the pressure chamber and to let the hydraulic oil in the oil storage chamber be supplied to the pressure chamber to make up any hydraulic oil loss, maintaining the output.

1 . A pressure cylinder, comprising:
 a first cylinder body having accommodated therein a piston;   a second cylinder body defining therein a first passage vertically connected to said first cylinder body, an oil storage chamber vertically connected to said first passage, a second passage vertically connected to said oil storage chamber and a pressure chamber vertically connected to said second passage, said oil storage chamber having a cross-sectional area larger than the cross-sectional area of said pressure chamber; and   a piston rod inserted through said first passage of said second cylinder body in an airtight manner, said piston rod having a first end connected to said piston and a second end suspending in said second cylinder body, said piston rod being movable by said piston to move said second end between a first position in said oil storage chamber and a second position in said pressure chamber.   
     
     
         2 . The pressure cylinder as claimed in  claim 1 , wherein said second cylinder body further defines an oil-storage passage kept in communication between said oil storage chamber and the outside of the pressure cylinder, said oil-storage passage being covered with a visual inspection window. 
     
     
         3 . The pressure cylinder as claimed in  claim 2 , wherein said oil-storage passage of said second cylinder body is sealed with a threaded seal member. 
     
     
         4 . The pressure cylinder as claimed in  claim 2 , wherein said second cylinder body further defines a tapered hole located on a bottom side thereof and gradually reducing in diameter in direction toward said second passage. 
     
     
         5 . The pressure cylinder as claimed in  claim 4 , wherein said oil storage chamber and said oil-storage passage of said second cylinder body are formed in an integral part of the second cylinder body. 
     
     
         6 . The pressure cylinder as claimed in  claim 5 , wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body. 
     
     
         7 . The pressure cylinder as claimed in  claim 4 , wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body. 
     
     
         8 . The pressure cylinder as claimed in  claim 2 , wherein said oil storage chamber and said oil-storage passage of said second cylinder body are formed in an integral part of the second cylinder body. 
     
     
         9 . The pressure cylinder as claimed in  claim 8 , wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body. 
     
     
         10 . The pressure cylinder as claimed in  claim 2 , wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body. 
     
     
         11 . The pressure cylinder as claimed in  claim 2 , further comprising an air passage connected between said first chamber and said second chamber at an elevation equal to the elevation of said oil-storage passage relative to said oil storage chamber, and an electromagnetic valve adapted for controlling a compressed air in and out of said air passage. 
     
     
         12 . The pressure cylinder as claimed in  claim 1 , wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body. 
     
     
         13 . The pressure cylinder as claimed in  claim 1 , wherein said oil storage chamber and said second passage of said second cylinder body are formed in an integral part of the second cylinder body. 
     
     
         14 . The pressure cylinder as claimed in  claim 1 , wherein said second cylinder body further defines a tapered hole located on a bottom side thereof and gradually reducing in diameter in direction toward said second passage. 
     
     
         15 . The pressure cylinder as claimed in  claim 14 , wherein said oil storage chamber and said oil-storage passage of said second cylinder body are formed in an integral part of the second cylinder body. 
     
     
         16 . The pressure cylinder as claimed in  claim 15 , wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body. 
     
     
         17 . The pressure cylinder as claimed in  claim 14 , wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body. 
     
     
         18 . The pressure cylinder as claimed in  claim 1 , wherein said second cylinder body further defines an oil output passage extending from said pressure chamber to the outside of said second cylinder body. 
     
     
         19 . The pressure cylinder as claimed in  claim 18 , wherein said second cylinder body further defines a bottom chamber kept in communication with said pressure chamber and disposed at a farther location in axial direction relative to said oil-output passage.