Telescopic hydraulic cylinder

Abstract

An extension cylinder is provided and includes an elongated tube having a distal end, a proximal end, and a first fluid opening formed proximate the proximal end. The extension cylinder also includes an elongated rod that is telescopically received within the elongated tube through the distal end thereof. The elongated rod has a second fluid opening formed proximate a rod distal end. A fluid communication tube is disposed between, and enables fluid communication between, the first and second fluid openings. The fluid communication tube includes a length that varies depending on how far the elongated rod is extended or retracted from the distal end of the elongated tube.

What is claimed is:  
     
         1 . An extension cylinder, comprising: 
 an elongated tube having a distal end, a proximal end, and a first fluid opening formed proximate the proximal end;    an elongated rod that is telescopically received within the elongated tube through the distal end thereof, the elongated rod having a second fluid opening formed proximate a rod distal end; and    a fluid communication tube disposed between, and enabling fluid communication between, the first and second fluid openings, wherein the fluid communication tube includes a length that varies depending on how far the elongated rod is extended or retracted from the distal end of the elongated tube.    
     
     
         2 . The extension cylinder of  claim 1 , wherein the fluid communication tube comprises: 
 a first fluid chamber formed by an interior surface of the elongated rod; and    a second fluid chamber formed by an interior surface of an internal tube member that is positioned within the elongated tube, wherein at least a portion of the internal tube member extends into the first fluid chamber, the internal tube member and the first fluid chamber being configured such that the amount of the internal tube member that extends into the first fluid chamber varies depending on how far the elongated rod is extended or retracted from the distal end of the elongated tube, thereby enabling uninterrupted fluid communication between the first and second fluid openings during and following an extension or retraction of the elongated rod.    
     
     
         3 . The extension cylinder of  claim 2 , wherein the elongated tube further comprises a tube interior surface that forms an extension chamber, the internal tube member and the elongated rod being radially displaced from the tube interior surface.  
     
     
         4 . The extension cylinder of  claim 3 , further comprising a piston attached to the elongated rod, the piston being slidably received within the extension chamber.  
     
     
         5 . The extension cylinder of  claim 1 , wherein the elongated tube further comprises a tube interior surface that forms an extension chamber, said fluid communication tube being radially displaced from the tube interior surface.  
     
     
         6 . The extension cylinder of  claim 5 , further comprising a piston attached to the elongated rod and dividing the extension chamber into first and second portions, the piston being configured to extend or retract the elongated rod in response to fluid being added and subtracted to the first and second portions of the extension chamber.  
     
     
         7 . The extension cylinder of  claim 1 , further comprising a base end member that is attached to the proximal end of the elongated tube and includes a fluid conduit opening and a fluid chamber formed by an interior surface, wherein the fluid chamber extends between, and enables fluid communication between, the fluid conduit opening and the first fluid opening formed proximate the proximal end of the elongated tube.  
     
     
         8 . The extension cylinder of  claim 1 , further comprising a base end member that is attached to the proximal end of the elongated tube, wherein the fluid communication tube extends through the base end member.  
     
     
         9 . The extension cylinder of  claim 1 , further comprising a rod end member that is attached to the distal end of the elongated rod and includes a fluid conduit opening and a fluid chamber formed by an interior surface, wherein the fluid chamber extends between, and enables fluid communication between, the fluid conduit opening and the second fluid opening.  
     
     
         10 . The extension cylinder of  claim 1 , further comprising: 
 a rod end member that includes a fluid conduit opening that is connected to a fluid chamber formed by an interior surface, wherein the fluid chamber extends through the rod end member and enables fluid communication to the fluid conduit opening;    a rod extension piece that is secured between the distal end of the elongated rod and the rod end member, wherein the rod extension piece includes an extension fluid chamber formed by an interior surface, and wherein the extension fluid chamber extends between, and enables fluid communication between, the second fluid opening and the fluid conduit opening.    
     
     
         11 . The extension cylinder of  claim 10 , wherein an extension coupler is secured between the distal end of the elongated rod and the rod extension piece to facilitate connection of the rod extension piece to the distal end of the elongated rod.  
     
     
         12 . The extension cylinder of  claim 1 , further comprising a rod end member that is attached to the distal end of the elongated rod, wherein the fluid communication tube extends through the base end member.  
     
     
         13 . An actuator rod for use within a hydraulic extension cylinder, comprising: 
 a proximal end and a distal end;    an exterior surface;    a fluid opening formed proximate the distal end;    a tube-receiving opening formed proximate the proximal end;    a fluid chamber formed by an interior surface of the elongated rod, the fluid chamber being connected to, and extending between, the fluid and tube-receiving openings; and    a piston engaged proximate the proximal end and having a piston opening configured to accommodate and prevent significant obstruction of the tube-receiving opening.    
     
     
         14 . The actuator rod of  claim 13 , further comprising a rod end member that is attached to the distal end and includes a fluid conduit opening and a fluid chamber formed by an interior surface, wherein the fluid chamber extends between, and enables fluid communication between, the fluid conduit opening and the fluid opening.  
     
     
         15 . The actuator rod of  claim 13 , further comprising: 
 a rod end member that includes a fluid conduit opening that is connected to a fluid chamber formed by an interior surface, wherein the fluid chamber extends through the rod end member and enables fluid communication to the fluid conduit opening;    a rod extension piece that is secured between the distal end of the actuator rod and the rod end member, wherein the rod extension piece includes an extension fluid chamber formed by an interior surface, and wherein the extension fluid chamber extends between, and enables fluid communication between, the fluid opening of the actuator rod and the fluid conduit opening of the rod end member.    
     
     
         16 . The actuator rod of  claim 15 , wherein an extension coupler is secured between the distal end of the actuator rod and the rod extension piece to facilitate connection of the rod extension piece to the distal end of the elongated rod.  
     
     
         17 . The actuator rod of  claim 13 , further comprising a rod end member that is attached to the distal end of the actuator rod, wherein the fluid chamber formed by an interior surface of the elongated rod extends through the base end member.  
     
     
         18 . A power machine, comprising: 
 a frame;    a plurality of ground engaging wheels supporting the frame;    a cab operably coupled to the frame and defining an operator compartment;    an engine operably coupled to the wheels;    a telescoping lift arm operably coupled to the frame;    a hydraulically actuated device secured to the power machine proximate a distal end of the telescoping lift arm; and    a hydraulic cylinder that is attached to a portion of the telescoping lift arm for extending and retracting the telescoping lift arm, while at the same time providing a path for fluid communication to the hydraulically actuated device, comprising: 
 an elongated tube having a distal end, a proximal end, and a first fluid opening formed proximate the proximal end;  
 an elongated rod that is telescopically received within the elongated tube through the distal end thereof, the elongated rod having a second fluid opening formed proximate a rod distal end; and  
 a fluid communication tube disposed between, and enabling fluid communication between, the first and second fluid openings, wherein the distance between the first and second fluid openings varies depending on how far the elongated rod is extended or retracted form the distal end of the elongated tube.  
   
     
     
         19 . The power machine of  claim 18 , wherein the fluid communication tube comprises: 
 a first fluid chamber formed by an interior surface of the elongated rod; and    a second fluid chamber formed by an interior surface of an internal tube member that is positioned within the elongated tube, wherein at least a portion of the internal tube member extends into the first fluid chamber, the internal tube member and the first fluid chamber being configured such that the amount of the internal tube member that extends into the first fluid chamber varies depending on how far the elongated rod is extended or retracted from the distal end of the elongated tube, thereby enabling uninterrupted fluid communication between the first and second fluid openings during and following an extension or retraction of the elongated rod.    
     
     
         20 . The power machine of  claim 18 , wherein the elongated tube further comprises a tube interior surface that forms an extension chamber, said fluid communication tube being radially displaced from the tube interior surface.