Self-charging hydraulic hammer

Patent metadata

Field	Value
Publication number	US-9656377-B2
Application number	US-201414455715-A
Country	US
Kind code	B2
Filing date	Aug 8, 2014
Priority date	Aug 8, 2014
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A self-charging assembly having a first side wall, a second side wall, a third sidewall, a first chamber, a second chamber, a first valve assembly, and a second valve assembly. The second side wall is disposed within the first side wall. The third sidewall connects the first side wall and the second side wall. The first chamber is defined by the first, second, and third sidewalls. The second chamber is disposed within the first chamber and is defined by the second side wall. The first valve assembly is configured to selectively place an interior portion of the second chamber in communication with an atmosphere outside of the self-charging assembly. The second valve assembly is configured to selectively place an interior portion of the first chamber in communication with the interior portion of the second chamber.

First claim

What is claimed is:

1. A self-charging assembly for a hammer assembly, the self-charging assembly comprising:
a first side wall,
a second side wall disposed within the first side wall, and
a third side wall connecting the first side wall and the second side wall;
a first gas chamber defined by the first side wall, the second side wall and the third side wall, the first gas chamber configured to hold a compressible gas;
a second gas chamber disposed within the first gas chamber and defined by the second side wall, the second gas chamber configured to hold a compressible gas;
a first valve assembly configured for selectively placing an interior portion of the second gas chamber in communication with an atmosphere outside of the self-charging assembly; and
a second valve assembly having,
an inflow valve configured to
place the interior portion of the first gas chamber in communication with interior portion of the second gas chamber when an air pressure within the first gas chamber is below an air pressure of the second gas chamber, and
block communication between the interior portion of the second gas chamber and the interior portion of the first gas chamber when the air pressure within the first gas chamber is greater than the air pressure in the second gas chamber, and

an outflow valve configured to
place the interior portion of the first gas chamber in communication with interior portion of the second gas chamber when an air pressure within the first gas chamber is greater than or equal to a threshold pressure, and
block communication between the interior portion of the second gas chamber and the interior portion of the first gas chamber when the air pressure within the first gas chamber is less than the threshold pressure.

2. The self-charging assembly according to claim 1 , wherein the first valve assembly is configured to place the interior portion of the second gas chamber in communication with the atmosphere outside the self-charging assembly when an air pressure within the second gas chamber is below an air pressure of the atmosphere outside of the self-charging assembly; and
wherein the first valve assembly is configured to block communication between the interior portion of the second gas chamber and the atmosphere outside of the self-charging assembly when the air pressure within the second gas chamber is equal or greater than the air pressure in the atmosphere outside of the self-charging assembly.

3. The self-charging assembly according to claim 2 , wherein the first valve assembly is a check valve having a biasing member, which holds the check valve closed when the air pressure within the second gas chamber is equal or greater than the air pressure in the atmosphere outside of the self-charging assembly.

4. The self-charging assembly according to claim 1 , wherein the inflow valve is a check valve having a biasing member, which holds the check valve closed when the air pressure within the first chamber is greater than the air pressure in the second gas chamber.

5. The self-charging assembly according to claim 1 , wherein the threshold pressure is greater than or equal to 100 PSI and less than or equal to 230 PSI.

6. A hammer assembly comprising:
the self-charging assembly according to claim 1 ;
a work tool supported below the self-charging assembly; and
a piston movably disposed in the self-charging assembly between the second gas chamber and the work tool, the piston configured to move in a first direction away from the work tool, thereby compressing the compressible gas in the second gas chamber producing a biasing force on the piston acting in a second direction toward the work tool.

7. A self-charging assembly for a hydro-mechanical device, the self-charging assembly including
a first gas chamber configured to hold a compressible gas;
a second gas chamber disposed within the first gas chamber, the second gas chamber configured to hold a compressible gas;
a first flow passage connecting an interior portion of the second gas chamber with an atmosphere outside of the self-charging assembly, the first flow passage having a first valve assembly configured for selectively blocking flow through the first flow passage; and
a second flow passage connecting an interior portion of the first gas chamber with the interior portion of the second gas chamber, the second flow passage having a second valve assembly, the second valve assembly having
an inflow valve configured to
allow flow through the second flow passage when an air pressure within the first gas chamber is below an air pressure of the second gas chamber, and
block flow through the second flow passage when the air pressure within the first gas chamber is greater than the air pressure in the second gas chamber, and

an outflow valve configured to
allow flow through the second flow passage when an air pressure within the first gas chamber is greater than or equal to a threshold pressure, and
block flow through the second flow passage when the air pressure within the first gas chamber is less than the threshold pressure.

8. The self-charging assembly according to claim 7 , wherein the first valve assembly is configured to allow flow through the first flow passage when an air pressure within the second gas chamber is below an air pressure of the atmosphere outside of the self-charging assembly; and
wherein the first valve assembly is configured to block flow through the first flow passage when the air pressure within the second gas chamber is equal or greater than the air pressure in the atmosphere outside of the self-charging assembly.

9. The self-charging assembly according to claim 8 , wherein the first valve assembly is a check valve having a biasing member, which holds the check valve closed when the air pressure within the second chamber is equal or greater than the air pressure of the atmosphere outside of the self-charging assembly.

10. The self-charging assembly according to claim 7 , wherein the inflow valve is a check valve having a biasing member, which holds the check valve closed when the air pressure within the first chamber is greater than the air pressure in the second gas chamber.

11. The self-charging assembly according to claim 7 , wherein the threshold pressure is greater than or equal to 100 PSI and less than or equal to 230 PSI.

12. A hydro-mechanical device comprising:
the self-charging assembly according to claim 7 ; and
a piston movably disposed in the self-charging assembly between the second gas chamber and a work tool, the piston configured to move in a first direction away from the work tool, thereby compressing the compressible gas in the second gas chamber producing a biasing force on the piston acting in a working direction opposite the first direction.

13. A method of charging a hydro-mechanical device having a self-charging assembly with a compressible gas, the self-charging assembly defining a first gas chamber and a second gas chamber, and having a piston movably disposed in the self-charging assembly adjacent the second gas chamber, the method comprising:
moving the piston toward the second gas chamber to decrease an internal volume of the second gas chamber;
opening an inflow valve to allow communication from the second gas chamber to the first gas chamber, when a pressure within the second gas chamber exceeds a pressure within the first gas chamber;
closing the inflow valve to block communication from second gas chamber to the first gas chamber when the pressure within the first gas chamber equals or is less than the pressure within the second gas chamber;
moving the piston away from the second gas chamber to incre

Assignees

• Caterpillar Inc

Inventors

• Moore Cody Thomas
• Fisher Bart A

Classifications

• B25D2250/375

  Fluid springs · CPC title

• F15B11/072

  Combined pneumatic-hydraulic systems (F15B11/032 takes precedence) · CPC title

• B25D9/12

  comprising a built-in liquid motor {, i.e. the tool being driven by hydraulic pressure} · CPC title

• B25D9/18 Primary

  involving a piston-type slide valve · CPC title

• B25D9/16 Primary

  Valve arrangements therefor {(B25D9/145 takes precedence)} · CPC title