Axially Driven Piston-Cylinder Unit

Abstract

An axially driven piston-cylinder unit comprising a cylinder, a piston that can be moved back and forth in the axial direction of the cylinder, between first and second piston positions, and a drive element that can be moved back and forth in the axial direction of the cylinder and is mechanically connected to the piston by means of a piston rod. The piston rod is connected to the piston or the drive element against the pretension of an elastic device, in such a way that it can be moved axially in relation to the piston or the drive element, such that when the piston head comes into contact with the front wall of the cylinder borehole, on the side of the cylinder head, the other movement of the drive element is performed against the force of the elastic device, thus braking the drive element.

1 - 7 . (canceled) 
   
   
       8 . An axially driven piston-cylinder unit comprising:
 a cylinder having a cylinder bore with a top end face wall;   a piston having a piston head and being movable back and forth along an axial direction of the cylinder between a first piston position, in which a cylinder chamber enclosed between the piston and the cylinder is largest, and a second piston position, in which the cylinder chamber is smallest;   a drive element being movable back and forth along the axial direction of the cylinder; and   a piston rod mechanically coupling the drive element and the piston and including a first end coupled to the piston and a second end coupled to the drive element; and   an elastic device coupling the piston rod to at least one of the piston and the drive element with the piston rod being movable axially relative to at least one of the piston and the drive element respectively against a pretensioning force of the elastic device such that, when the piston moves into the second piston position at the top end face wall, the piston head lands on the top end face wall of the cylinder bore, then the further movement of the drive element is made against the force of the elastic device, and thus the drive element is braked.   
   
   
       9 . The axially driven piston-cylinder unit as claimed in  claim 8 , further comprising:
 an opening provided in the piston head and the first end of the piston rod extending through the opening;   the piston rod being movable in relation to the piston in the axial direction of the piston;   the elastic device coupling the piston rod and the piston; and   the elastic device pretensioning the piston rod from the piston towards the drive device, the piston rod including a piston end-stop restricting the piston rod from coming out of the opening.   
   
   
       10 . The axially driven piston-cylinder unit as claimed in  claim 9 , wherein the piston rod has a sealed passage into the piston opening and a seal surrounding the piston rod. 
   
   
       11 . The axially driven piston-cylinder unit as claimed in  claim 9 , wherein the elastic device includes an annular spring disk. 
   
   
       12 . The axially driven piston-cylinder unit as claimed in  claim 8 , further comprising:
 an opening provided in the drive element and the second end of the piston rod extends through the opening;   the piston rod being movable in relation to the drive element in the axial direction of the drive element;   the drive elastic device coupling the piston rod and the drive element; and   the drive elastic device pretensioning the piston rod from the drive element towards the piston, the piston rod including a drive end-stop restricing the piston rod from coming out of the drive opening.   
   
   
       13 . The axially driven piston-cylinder unit as claimed in  claim 12 , wherein the elastic device includes a spring. 
   
   
       14 . The axially driven piston-cylinder unit as claimed in  claim 8 , wherein the piston is subject to the back and forth drive from a movable drive element of a linear drive. 
   
   
       15 . A compressor for producing a pressurized fluid comprising:
 at least one axially driven piston-cylinder unit comprising:
 a cylinder having a cylinder bore with a top end face wall; 
 a piston having a piston head and movable back and forth along an axial direction of the cylinder between a first piston position, in which a cylinder chamber enclosed between the piston and the cylinder is largest, and a second piston position, in which the cylinder chamber is smallest; 
 a drive element being movable back and forth along the axial direction of the cylinder; and 
 a piston rod mechanically coupling the drive element and the piston and including a first end coupled to the piston and a second end coupled to the drive element; and 
 an elastic device coupling the piston rod to at least one of the piston and the drive element with the piston rod being movable axially relative to at least one of the piston and the drive element respectively against a pretensioning force of the elastic device such that, when the piston moves into the second piston position at the top end face wall, the piston head lands on the top end face wall of the cylinder bore, then the further movement of the drive element is made against the force of the elastic device, and thus the drive element is braked. 
   
   
   
       16 . The compressor as claimed in  claim 15 , further comprising:
 an opening provided in the piston head and the first end of the piston rod extending through the opening;   the piston rod being movable in relation to the piston in the axial direction of the piston;   the elastic device coupling the piston rod and the piston; and   the elastic device pretensioning the piston rod from the piston towards the drive device, the piston rod including a piston end-stop restricting the piston rod from coming out of the opening.   
   
   
       17 . The compressor as claimed in  claim 16 , wherein the piston rod has a sealed passage into the piston opening and a seal surrounding the piston rod. 
   
   
       18 . The compressor as claimed in  claim 16 , wherein the elastic device includes an annular spring disk. 
   
   
       19 . The compressor as claimed in  claim 15 , further comprising:
 an opening provided in the drive element and the second end of the piston rod extends through the opening;   the piston rod being movable in relation to the drive element in the axial direction of the drive element;   the drive elastic device coupling the piston rod and the drive element; and   the drive elastic device pretensioning the piston rod from the drive element towards the piston, the piston rod including a drive end-stop restricing the piston rod from coming out of the drive opening.   
   
   
       20 . The compressor as claimed in  claim 19 , wherein the elastic device includes a spring. 
   
   
       21 . The compressor as claimed in  claim 15 , wherein the piston is subject to the back and forth drive from a movable drive element of a linear drive.