Contaminant removal from a hydraulic cylinder

• US 3,943,717 A
• Filed: 02/13/1975
• Issued: 03/16/1976
• Est. Priority Date: 01/07/1974
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Americas Company (Caterpillar Incorporated)
• Inventors: Schexnayder, Lawrence F.
• Primary Examiner(s): Geoghegan, Edgar W.
• Application Number:
  US05/549,609
• Time in Patent Office: 397 Days
• Field of Search: 60/378, 60/453, 60/454, 60/455, 92/82, 92/86, 92/165 R, 277/19, 277/59
• US Class Current: 60/453
• CPC Class Codes: F16J 15/004 forming of recuperation chamber for the leaking fluid
• CPC Class Codes: F16J 15/40 by means of fluid

Abstract

A hydraulic cylinder comprises a piston reciprocally mounted in a housing thereof. A pair of annular sealing means, slidably receiving a rod of the piston, are disposed on either side of an annular chamber which has pressurized fluid pumped therethrough for flushing purposes.

Claims

1. A hydraulic cylinder in combination with flushing means therefor, said cylinder comprising

a housing,

a piston reciprocally mounted in said housing, and

inboard and outboard annular sealing means mounted on said housing for slidably receiving a rod of said reciprocating piston in sealing contact therewith, said flushing means comprising

means forming an annular chamber in said housing, said chamber disposed axially between said inboard and outboard sealing means,

a pressurized fluid source, including a pump and a reservoir, and

conduit means communicating said pump with said chamber and said chamber with said reservoir for continuously circulating fluid into and out of said chamber for flushing out and for pressurizing said chamber, said inboard annular sealing means comprising annular buffer seal means for substantially restricting outflow of pressurized fluid from one of said working chambers and a separate annular first lip seal disposed adjacent to said buffer seal and facing axially theretowards, said buffer seal means including a flat elastomeric ring member.

2. The combination of claim 1 wherein said pressurized fluid source further comprises a second pump operatively connected to working chambers disposed at head and rod ends of said cylinder and further comprising control valve means operatively connected between said second pump and said working chambers for selectively and alternately pressurizing and exhausting said working chambers of said cylinder.

3. The combination of claim 1 wherein said flushing means further comprise filter means operatively connected in said conduit means between said cylinder and said reservoir for removing contaminants tending to collect in said chamber.

4. The combination of claim 1 further comprising a second said hydraulic cylinder integrated into said conduit means, between said first-mentioned cylinder and said reservoir, an inlet to the annular chamber of said second cylinder operatively connected by said conduit means to an outlet of the annular chamber of said first-mentioned cylinder and having an outlet thereof operatively connected by said conduit means to said reservoir.

5. The invention of claim 1 wherein said outboard annular sealing means comprises a second separate annular lip seal facing inwardly towards said first sealing means and a third separate annular lip seal facing axially away from said second lip seal.

6. A hydraulic cylinder in combination with flushing means therefor, said cylinder comprising

a housing,

a piston reciprocally mounted in said housing, and

inboard and outboard annular sealing means mounted on said housing for slidably receiving a rod of said reciprocating piston in sealing contact therewith, said flushing means comprising

means forming an annular chamber in said housing, said chamber disposed axially between said inboard and outboard sealing means,

a pressurized fluid source, including a pump and a reservoir, and

conduit means communicating said pump with said chamber and said chamber with said reservoir for continuously circulating fluid into and out of said chamber for flushing out and for pressurizing said chamber, said pressurized fluid source further comprising a second pump operatively connected to working chambers disposed at head and rod ends of said cylinder and further comprising control valve means operatively connected between said second pump and said working chambers for selectively and alternately pressurizing and exhausting said working chambers of said cylinder, said inboard annular sealing means comprising annular buffer seal means for substantially restricting outflow of pressurized fluid from one of said working chambers and a separate annular first lip seal disposed adjacent to said buffer seal and facing axially theretowards, said buffer seal means including a flat elastomeric ring member.

7. The combination of claim 6 wherein said outboard annular sealing means comprises a second separate annular lip seal facing inwardly towards said first sealing means and a third separate annular lip seal facing axially away from said second lip seal.