Hydraulic system of a tool

Patent metadata

Field	Value
Publication number	US-10428843-B2
Application number	US-201715616588-A
Country	US
Kind code	B2
Filing date	Jun 7, 2017
Priority date	Jun 8, 2016
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

An example tool includes a hydraulic actuator cylinder; a piston slidably accommodated within the hydraulic actuator cylinder, where the piston includes a piston head and a piston rod extending from the piston head along a central axis direction of the hydraulic actuator cylinder, the piston head divides an inside of the hydraulic actuator cylinder into a first chamber and a second chamber, and the piston rod is disposed in the first chamber and configured to move one or more jaws of the tool; a pump configured to provide pressurized fluid; and a sequence valve configured to block the pressurized fluid from flowing into the second chamber of the hydraulic actuator cylinder until pressure of the pressurized fluid exceeds a threshold pressure value.

First claim

What is claimed is:

1. A tool comprising:
a hydraulic actuator cylinder;
a piston slidably accommodated within the hydraulic actuator cylinder, wherein the piston includes a piston head and a piston rod extending from the piston head along a central axis direction of the hydraulic actuator cylinder, wherein the piston head divides an inside of the hydraulic actuator cylinder into a first chamber and a second chamber, wherein the piston is partially hollow, and wherein the piston rod is disposed in the first chamber and configured to move one or more jaws of the tool;
a pump configured to provide pressurized fluid;
a sequence valve configured to block the pressurized fluid from flowing into the second chamber of the hydraulic actuator cylinder until pressure of the pressurized fluid exceeds a threshold pressure value, wherein when the tool is triggered:
the pump provides the pressurized fluid to a hollow portion of the piston, causing the piston to extend at a first speed until at least one of the one or more jaws reach an object placed therebetween, and
thereafter, pressure of the pressurized fluid increases until the pressure reaches the threshold pressure value, causing the sequence valve to open providing a path for the pressurized fluid to the second chamber, causing the piston to extend at a second speed; and

a high pressure check valve configured to prevent the pressurized fluid from flowing into the second chamber as the piston extends at the first speed.

2. The tool of claim 1 , wherein the hydraulic actuator cylinder has a first end proximate to the one or more jaws and a second end opposite the first end, wherein the first chamber is formed between the piston head, the piston rod, and the first end of the hydraulic actuator cylinder, and wherein the second chamber is formed between the piston head and the second end of the hydraulic actuator cylinder.

3. The tool of claim 1 , further comprising:
an extension cylinder disposed within the partially hollow piston, wherein the extension cylinder is affixed to the hydraulic actuator cylinder at the second end, wherein the piston is configured to slide axially about an external surface of the extension cylinder as the piston extends, and wherein the pump provides the pressurized fluid to the hollow portion of the piston through the extension cylinder, causing the piston to extend at the first speed.

4. The tool of claim 3 , wherein the second chamber includes a portion of the extension cylinder.

5. The tool of claim 1 , further comprising:
a bypass check valve; and
a reservoir containing fluid having a respective pressure less than the pressure of the pressurized fluid, wherein, as the piston extends at the first speed, the bypass check valve allows fluid to be drawn from the reservoir into the second chamber to fill the second chamber.

6. The tool of claim 5 ,
wherein the high pressure check valve is configured to provide a path for fluid in the second chamber to flow back to the reservoir.

7. The tool of claim 1 , wherein when the sequence valve opens, the pressurized fluid flows into both the hollow portion and the second chamber.

8. The tool of claim 1 , wherein the threshold pressure value is a first threshold pressure value, the tool further comprising:
a motor configured to drive the pump;
a pressure sensor configured to provide sensor information indicative of the pressure of the pressurized fluid; and
a controller in communication with the motor and the pressure sensor, and configured to receive the sensor information from the pressure sensor, wherein the controller is configured to shut-off the motor when the sensor information indicates that the pressure has exceeded a second threshold pressure value.

9. The tool of claim 8 , wherein the pressure reaches the second threshold pressure value after the piston reaches an end of stroke of the piston within the hydraulic actuator cylinder.

10. The tool of claim 1 , further comprising:
a manually operated release lever; and
a release valve actuatable by the release lever, wherein actuation of the release lever actuates the release valve, causing the release valve to provide a respective path for fluid within the hollow portion and the second chamber to flow back to a reservoir containing respective fluid having a respective pressure less than the pressure of the pressurized fluid.

11. The tool of claim 10 , wherein the release valve comprises a valve pin coupled to a valve ball, and wherein actuation of the release lever moves a lever coupled to the valve pin to apply a force on the valve pin to move the valve ball off of a seat of the valve ball and provide the respective path for the fluid within the hollow portion.

12. The tool of claim 11 , wherein the manually operated release lever is coupled to the tool by way of a hinge operable as a fulcrum, wherein the manually operated release lever comprises a screw and a protrusion, wherein the screw is closer to the hinge than the protrusion, such that the screw initially applies a first force on the lever, then loses contact with the lever as the protrusion contacts the lever to apply a second force on the lever, and wherein the second force is less than the first force.

13. The tool of claim 1 , wherein the threshold pressure value is a first threshold pressure value, the tool further comprising:
a burst disk in fluid communication with the pressurized fluid, wherein the burst disk is configured to rupture when the pressure of the pressurized fluid exceeds a second threshold pressure value, and wherein the ruptured burst disk provides a respective path for the pressurized fluid to flow back to a reservoir containing respective fluid having a respective pressure less than the pressure of the pressurized fluid.

14. The tool of claim 1 , further comprising:
a frame and a bore formed therein, wherein the frame and the bore form the hydraulic actuator cylinder.

15. A hydraulic circuit, comprising:
a hydraulic actuator cylinder;
a piston slidably accommodated within the hydraulic actuator cylinder, wherein the piston includes a piston head and a piston rod extending from the piston head along a central axis direction of the hydraulic actuator cylinder, wherein the piston head divides an inside of the hydraulic actuator cylinder into a first chamber and a second chamber, wherein the piston is partially hollow, and wherein the piston rod is disposed in the first chamber;
a pump configured to provide pressurized fluid;
a sequence valve configured to block the pressurized fluid from flowing into the second chamber of the hydraulic actuator cylinder until pressure of the pressurized fluid exceeds a threshold pressure value, wherein:
the pump provides the pressurized fluid to a hollow portion of the piston, causing the piston to extend at a first speed until the piston rod meets a resistance, and
thereafter, pressure of the pressurized fluid increases until the pressure reaches the threshold pressure value, causing the sequence valve to open providing a path for the pressurized fluid to the second chamber, causing the piston to extend at a second speed; and

a high pressure check valve configured to prevent the pressurized fluid from flowing into the second chamber as the piston extends at the first speed.

16. The hydraulic circuit of claim 15 , wherein the hydraulic actuator cylinder has a first end proximate to the one or more jaws and a second end opposite the first end, wherein the first chamber is formed between the piston head, the piston rod, and the first end of the hydraulic actuator cylinder, and wherein the seco

Assignees

• Milwaukee Electric Tool Corp

Inventors

• Ballard James
• Zimmermann Ian
• Skinner Luke
• Norquist Eric

Classifications

• F15B2211/7057

  being of the telescopic type · CPC title

• B25B27/026

  fluid driven · CPC title

• H01R43/048

  Crimping apparatus or processes (H01R43/042 takes precedence) · CPC title

• F15B2211/6313

  the pressure being a load pressure · CPC title

• F15B15/16

  of the telescopic type · CPC title