Jack device and work machine equipped with same

Patent metadata

Field	Value
Publication number	US-12454252-B2
Application number	US-202118044643-A
Country	US
Kind code	B2
Filing date	Sep 14, 2021
Priority date	Sep 30, 2020
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

Provided is a jack device rendering an operation of changing the posture of a jack cylinder easy without using a device that actively changes the posture. The jack device includes an arm, a jack body including the jack cylinder, and a reaction-force application unit supported by the arm. The reaction-force application unit makes a reaction-force moment act on the jack body in all postures from the upright posture to the storage posture in response to a force applied from the jack body. The reaction-force application unit makes a reaction-force moment greater than a self-weight moment act on the jack body in the storage posture and makes a reaction-force moment smaller than the self-weight moment act on the jack body in the upright posture.

First claim

The invention claimed is:

1 . A jack device attached to a machine body of a work machine including the machine body to be able to lift up the machine body, the jack device comprising:
an arm mountable on the machine body so as to be rotatable about an arm rotation axis extending in a machine up-down direction, which is an up-down direction of the machine body; a jack body including a jack cylinder expandable and contractable in a cylinder expansion-contraction direction and attached to the arm rotatably about a cylinder rotation axis to be shiftable between an upright posture and a storage posture, the upright posture being a posture where the jack body is capable of lifting up the machine body by expansion of the jack cylinder and the storage posture being a posture where the cylinder expansion-contraction direction is tilted from the machine up-down direction more largely than the upright posture and the jack cylinder lies along an upper surface of the arm; and a reaction-force application unit supported by the arm and configured to apply a reaction force to the jack body in response to a force applied from the jack body to make a reaction-force moment act on the jack body in all postures from the upright posture to the storage posture, the reaction-force moment being a moment caused by the reaction force about the cylinder rotation axis and having a direction to make the jack body closer to the storage posture, wherein the reaction-force application unit is configured to make the reaction-force moment greater than a self-weight moment act on the jack body in the storage posture and configured to make the reaction-force moment smaller than the self-weight moment act on the jack body in the upright posture, the self-weight moment being a moment caused by a weight of the jack body about the cylinder rotation axis and having a direction to make the jack body closer to the upright posture, and the reaction-force application unit includes at least one reaction-force application member composed of a gas spring, which includes a gas housing filled with a reaction-force application gas and configured to generate the reaction force by the reaction-force application gas with expansion and contraction in a gas-spring expansion-contraction direction in response to the force applied from the jack body.

2 . The jack device according to claim 1 , wherein the gas-spring expansion-contraction direction is a longitudinal direction of the reaction-force application member, and the reaction-force application unit is supported by the arm rotatably about a reaction-force-application-unit rotation axis, which is located at a center part of the reaction-force application member with respect to the longitudinal direction.

3 . The jack device according to claim 1 , further comprising a cover that covers at least a part of the reaction-force application unit, the gas spring including the gas housing and a piston rod held by the gas housing capably of relative movement to the gas housing in the gas-spring expansion-contraction direction, and the cover covers at least the piston rod of the gas spring.

4 . The jack device according to claim 1 , wherein the jack body includes a jack weight, which is incorporated into the jack body so as to make the center of gravity of the jack body closer to the cylinder rotation axis than the center of gravity of the jack body without the jack weight.

5 . A work machine comprising:
a machine body defining a storage space; and a jack device according to claim 1 , the jack device mounted on the machine body, wherein the jack device is shiftable between a use state where the jack device projects from the machine body to an outside of the storage space to enable expansion of the jack cylinder in the upright posture to lift up the machine body and a storage state where the jack cylinder is stored in the storage space in the storage posture, by a rotation of the arm relative to the machine body about the arm rotation axis.

Assignees

• Kobelco Constr Mach Co Ltd

Inventors

• Arita Ryuichi

Classifications

• E02F9/085 Primary

  Ground-engaging fitting for supporting the machines while working, e.g. outriggers, legs (for vehicles in general B60S9/00, for cranes B66C23/78) · CPC title

• B66F3/26

  Adaptations or arrangements of pistons · CPC title

• B66F3/247

  pneumatically actuated (B66F3/35 takes precedence) · CPC title

• B66C23/78

  Supports, e.g. outriggers, for mobile cranes · CPC title

• E02F9/2271

  Actuators and supports therefor and protection therefor · CPC title