US 6,742,440 B2 · Servo-controlled integral stop for use with a servo-controlled hydraulic piston

Abstract

Apparatus, and an accompanying method for use therein, that utilizes working and stopping servo-controlled hydraulic pistons wherein the stopping piston acts as a controlled mechanical stop for the working piston. Both pistons are spaced apart along and coaxially arranged around a common shaft, with each piston moving in a separate cylinder. The working piston is securely attached to the shaft, while the shaft moves through a central, longitudinal bore of the stopping piston. The stopping piston effectively “floats” in its cylinder and produces a greater force than the working piston. A radially extending stop element, situated on the shaft, has a surface configured to abuttingly engage with a complementary surface on the stopping piston such that the stopping piston, once appropriately positioned, controllably stops continued movement of the working piston in a very short time and over a very short distance with little strain induced in the apparatus.

Claims14

Dependent claims

Apparatus for providing a controlled mechanical stop that halts further movement of a first hydraulic piston, the apparatus comprising:

the first hydraulic piston controllably moveable in a first piston cylinder, the first piston having a piston shaft attached to the first piston and extending outwardly therefrom;
a second hydraulic piston controllably positionable in a second piston cylinder to a desired stopping position therein, said second cylinder being separate from the first piston cylinder and said second piston producing greater force than the first piston;
the shaft extending longitudinally through a bore in second piston such that shaft can slidably move through the second piston;
and
a stopping element situated on the shaft such that during movement of the first piston and the shaft in a predefined direction, the stopping element will abuttingly engage with the second piston at the stopping position such the second piston will over-power and stop further movement of the shaft and the first piston in the predefined direction.

2 more elements

In apparatus for providing a controlled mechanical stop that halts further movement of a first hydraulic piston, the apparatus having:

the first hydraulic piston controllably moveable in a first piston cylinder, the first piston having a piston shaft attached to the first piston and extending outwardly therefrom;
a second hydraulic piston controllably positionable in a second piston cylinder to a desired stopping position therein, said second cylinder being separate from the first piston cylinder and said second piston producing greater force than the first piston;
the shaft extending longitudinally through a bore in second piston such that shaft can slidably move through the second piston;
and
a stopping element situated on the shaft;
a method comprising the steps of:
moving the second piston to the stopping position and thereafter holding the second piston in said stopping position;
and
then moving the first piston at a predetermined rate and in a predefined direction until such time as the first stopping surface of the stopping element abuttingly engages with the second piston such that the second piston over-powers continued movement of the first piston and halts further movement thereof in the predefined direction.

6 more elements

Dependencies are inferred from the claim text.

Servo-controlled integral stop for use with a servo-controlled hydraulic piston

Life of this patent

Servo-controlled integral stop for use with a servo-controlled hydraulic piston

Life of this patent

Abstract

Claims14