Hammer protection system and method

Patent metadata

Field	Value
Publication number	US-10377028-B2
Application number	US-201615068645-A
Country	US
Kind code	B2
Filing date	Mar 14, 2016
Priority date	Mar 14, 2016
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

A hydraulic hammer is provided. The hydraulic hammer includes a fluid inlet configured to receive a pressurized fluid for running the hydraulic hammer and a fluid outlet for discharging hydraulic fluid from the hydraulic hammer. A bypass passage fluidly connects the fluid inlet and the fluid outlet, the bypass passage has a bypass inlet fluidly connected to the fluid inlet and a bypass outlet fluidly connected to the fluid outlet. An automatic shut-off valve is disposed in the bypass passage between the bypass inlet and the bypass outlet and is configured to open or close the bypass passage. The automatic shut-off valve is configured to open the bypass passage under pressure of the pressurized fluid on continuous running of the hydraulic hammer for a set time to stop the hammer.

First claim

What is claimed is:

1. A hydraulic hammer comprising:
a fluid inlet configured to receive a pressurized fluid for running the hydraulic hammer;
a fluid outlet for discharging hydraulic fluid from the hydraulic hammer;
a bypass passage fluidly connecting the fluid inlet and the fluid outlet, the bypass passage having a bypass inlet fluidly connected to the fluid inlet and a bypass outlet fluidly connected to the fluid outlet; and
an automatic shut-off valve disposed in the bypass passage between the bypass inlet and the bypass outlet and configured to open or close the bypass passage,
wherein the automatic shut-off valve is configured to open the bypass passage under pressure of the pressurized fluid on continuous running of the hydraulic hammer for a set time thereby stopping the hammer,
wherein the automatic shut-off valve includes:
a cavity, and
a spool provided in the cavity, the spool being movable within the cavity between an open position to fluidly connect the bypass inlet to the bypass outlet and a closed position to fluidly disconnect the bypass inlet from the bypass outlet,
wherein an intermediate cavity and a first orifice are defined in the spool, the first orifice extending from the intermediate cavity to a second chamber, and
wherein the first orifice is configured to allow flow of the volume of fluid through the first orifice from the second chamber at a restricted rate and thereby delay movement of the spool from the closed position to the open position under pressure of the pressurized fluid by the set time.

2. The hydraulic hammer of claim 1 , wherein the automatic shut-off valve further includes:
a first chamber fluidly connecting the bypass inlet to the bypass outlet,
the second chamber, which is configured to hold a volume of fluid against the spool to restrict the movement of the spool from the closed position to the open position, and
a biasing member configured to bias the spool towards the closed position.

3. The hydraulic hammer of claim 2 , further comprising:
a pressure equalization loop fluidly connecting the second chamber to the bypass outlet.

4. The hydraulic hammer of claim 3 , wherein the pressure equalization loop has a unidirectional check valve configured to block a flow of the hydraulic fluid from a first end towards the bypass outlet.

5. The hydraulic hammer of claim 3 , wherein the pressure equalization loop has a second orifice to restrict the flow of fluid in the pressure equalization loop, the second orifice is configured to allow the flow of fluid at a rate of at least five times greater than the rate of flow allowed by the first orifice.

6. The hydraulic hammer of claim 2 , wherein the biasing member is a spring.

7. They hydraulic hammer of claim 6 , wherein the spool pushes the spring while moving from the closed position to the open position, the spool having a stepped surface facing fluid from the bypass inlet to counter biasing force of the spring as the spool moves from the closed position to the open position.

8. The hydraulic hammer of claim 2 , wherein the first orifice fluidly connects the second chamber to the bypass outlet.

9. A hydraulic hammer comprising:
a housing;
a piston arranged for reciprocating motion within the housing when the hydraulic hammer is run;
a fluid inlet configured to receive pressurized fluid for running the hydraulic hammer;
a fluid outlet for discharging hydraulic fluid from the hydraulic hammer;
a bypass passage fluidly connecting the fluid inlet and the fluid outlet, the bypass passage having a bypass inlet fluidly connected to the fluid inlet and a bypass outlet fluidly connected to the fluid outlet; and
an automatic shut-off valve disposed in the bypass passage between the bypass inlet and the bypass outlet and configured to open or close the bypass passage, the automatic shut-off valve including:
a cavity,
a first chamber fluidly connecting the bypass inlet to the bypass outlet,
a spool provided in the cavity, the spool being movable within the cavity between an open position to fluidly connect the bypass inlet to the bypass outlet and a closed position to fluidly disconnect the bypass inlet from the bypass outlet, an intermediate cavity and a first orifice being defined in the spool, the first orifice extending from the intermediate cavity to a second chamber, and
a second chamber to hold a volume of fluid against the spool to restrict movement of the spool from the closed position towards the open position based on a flow of the volume of fluid from the second chamber,
wherein the first orifice is configured to allow the flow of the volume fluid from the second chamber at a restricted rate to delay movement of the spool from the closed position towards the open position by a set time.

10. The hydraulic hammer of claim 9 , wherein the automatic shut-off valve further comprises a biasing member configured to bias the spool towards the closed position.

11. The hydraulic hammer of claim 10 , wherein the biasing member is a spring, the spool configured to push the spring while moving from the closed position to the open position, the spool having a stepped surface facing fluid from the bypass inlet to counter increase in biasing force of the spring as the spool moves from the closed position towards the open position.

12. The hydraulic hammer of claim 9 , further comprising:
a pressure equalization loop fluidly connecting the second chamber to the bypass outlet.

13. The hydraulic hammer of claim 12 , wherein the pressure equalization loop has a unidirectional check valve to allow the flow of fluid from the bypass outlet towards the second chamber and block flow of fluid from the second chamber towards the bypass outlet.

14. The hydraulic hammer of claim 12 , wherein the pressure equalization loop has a second orifice to restrict the flow of fluid in the pressure equalization loop, the second orifice is configured to allow the flow of fluid at a rate of at least five times greater than the rate of flow allowed by the first orifice.

15. The hydraulic hammer of claim 9 , wherein the bypass passage and the automatic shut-off valve are positioned in the housing.

16. The hydraulic hammer of claim 9 , wherein the first orifice fluidly connects the second chamber to the bypass outlet.

17. A method of protecting a hydraulic hammer, the hydraulic hammer having a fluid inlet for receiving a pressurized fluid for running the hammer and a fluid outlet to discharge fluid from the hydraulic hammer, a bypass passage fluidly connecting the fluid inlet to the fluid outlet, and an automatic shut-off valve positioned in the bypass passage and configured to open or close the bypass passage, the automatic shut-off valve comprising a spool provided in a cavity and movable in the cavity between a closed position to close the bypass passage and an open position to open the bypass passage, the automatic shut-off valve being biased towards the closed position, an intermediate cavity and a first orifice being defined in the spool, the first orifice extending from the intermediate cavity to a second chamber, and the first orifice being configured to allow flow of the volume of fluid through the first orifice from the second chamber at a restricted rate and thereby delay movement of the spool from the closed position to the open position under pressure of the pressurized fluid by the set time, the method comprising:
operating the hammer by providing the pressurized fluid through a passage connected to the fluid inlet and simultaneously moving the automatic shut-off valve from the closed position t

Assignees

• Caterpillar Inc

Inventors

• Grzybowski Joshua
• Moore Cody

Classifications

• B25D9/12 Primary

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

• E02F5/30

  Auxiliary apparatus, e.g. for thawing, cracking, blowing-up, or other preparatory treatment of the soil · CPC title

• B25D9/20

  involving a tubular-type slide valve · CPC title

• B25D9/26

  Control devices for adjusting the stroke of the piston or the force or frequency of impact thereof {(control systems adapted for earth drilling E21B44/00)} · CPC title

• B25D9/16 Primary

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