Apparatus and method for maintaining positional alignment between two spaced-apart points on a moveable member

Claim 1

An apparatus for maintaining relative positional alignment between two spaced-apart points on a movable member, comprising: (a) a hydraulic pump; (b) first hydraulic means operatively connected to said hydraulic pump and to a first point on the member for applying a reference hydraulic pressure to the member and for moving the member to maintain said applied pressure at a constant, pre-determined pressure level; (c) second hydraulic means operatively connected to said hydraulic pump and to a second point on the member spaced apart from said first point; (d) sensing means cooperating with the member for detecting movement of the member at said first point relative to said second point; and (e) hydraulic servo-valve means cooperating with said sensing means and selectively directing hydraulic fluid to said second hydraulic means in response to said sensing means for moving the member at said second point in a direction and for a distance corresponding to the movement of the member at said first point, said hydraulic servo-valve means comprising a circular valve housing adapted for unison movement with one of said first and second points on the member and including port means for conveying hydraulic fluid to said second hydraulic means, and a valve body mounted for rotational movement within said valve housing and cooperating with the other of said first and second points on said movable member for directing fluid to said second hydraulic means in response to and proportional to the relative movement between said first point and said second point on the movable member; whereby tthe member at said second point follows the movement of the member at said first point and thereby maintains relative positional alignment between said first point and said second point on the member.

Claim 2

An apparatus for maintaining relative positional alignment between two spaced-apart points on a movable member, comprising: (a) a hydraulic pump; (b) first hydraulic means operatively connected to said hydraulic pump and to a first point on the member for applying a reference hydraulic pressure to the member and for moving the member to maintain said applied pressure at a constant, pre-determined pressure level; (c) second hydraulic means operatively connected to said hydraulic pump and to a second point on the member spaced apart from said first point; (d) sensing means cooperating with the member for detecting movement of the member at said first point relative to said second point; and (e) hydraulic servo-valve means cooperating with said sensing means and selectively directing hydraulic fluid to said second hydraulic means in response to said sensing means for moving the member at said second point in a direction and for a distance corresponding to the movement of the member at said first point, said hydraulic servo-valve means comprising a circular valve housing adapted for unison movement with one of said first and second points on the member and including port means for conveying hydraulic fluid to said second hydraulic means, and a valve body mounted for rotational movement within said valve housing and cooperating with the other of said first and second points on said movable member for directing fluid to said second hydraulic means in response to and proportional to the relative movement between said first point and said second point on the movable member; whereby tthe member at said second point follows the movement of the member at said first point and thereby maintains relative positional alignment between said first point and said second point on the member.

Claim 9

An apparatus for maintaining relative positional alignment in a plane between two spaced-apart points on a rotatable axle, comprising: (a) a hydraulic pump; (b) first hydraulic means operatively coupled to said hydraulic pump and to a first point on the axle for applying a reference hydraulic pressure to the axle and for moving the axle in said plane to maintain said applied pressure at a constant, pre-determined pressure level; (c) second hydraulic means operatively coupled to said hydraulic pump and to a second point on the axle spaced-apart from said first point; (d) sensing means cooperating with the axle for detecting movement of the axle at said first point relative to said second point; and (e) hydraulic servo-valve means cooperating with said sensing means and selectively directing hydraulic fluid to said second hydraulic means in response to said sensing means for moving the axle at said second point in a direction and for a distance corresponding to the movement of the axle at said first point, said hydraulic servo-valve means comprising a circular valve housing adapted for unison movement with one of said first and second points and including port means for conveying hydraulic fluid to said second hydraulic means, and a valve body mounted for rotational movement within said valve housing and cooperating with the other of said first and second points on said axle for directing fluid to said second hydraulic means in response to and proportional to the relative movement between said first point and said second point on the axle; whereby the axle at said second point follows the movement of the axle at said first point and thereby maintains relative positional alignment in said plane between said first point and said second point on the axle.

Claim 10

An apparatus for maintaining relative positional alignment in a plane between two spaced-apart points on a rotatable axle, comprising: (a) a hydraulic pump; (b) first hydraulic means operatively coupled to said hydraulic pump and to a first point on the axle for applying a reference hydraulic pressure to the axle and for moving the axle in said plane to maintain said applied pressure at a constant, pre-determined pressure level; (c) second hydraulic means operatively coupled to said hydraulic pump and to a second point on the axle spaced-apart from said first point; (d) sensing means cooperating with the axle for detecting movement of the axle at said first point relative to said second point; and (e) hydraulic servo-valve means cooperating with said sensing means and selectively directing hydraulic fluid to said second hydraulic means in response to said sensing means for moving the axle at said second point in a direction and for a distance corresponding to the movement of the axle at said first point, said hydraulic servo-valve means comprising a circular valve housing adapted for unison movement with one of said first and second points and including port means for conveying hydraulic fluid to said second hydraulic means, and a valve body mounted for rotational movement within said valve housing and cooperating with the other of said first and second points on said axle for directing fluid to said second hydraulic means in response to and proportional to the relative movement between said first point and said second point on the axle; whereby the axle at said second point follows the movement of the axle at said first point and thereby maintains relative positional alignment in said plane between said first point and said second point on the axle.

Claim 16

A method of maintaining relative positional alignment between two spaced-apart points on a movable member, comprising the steps of: (a) applying a hydraulic reference pressure to said member at a first point thereon; (b) moving said member at said first point to maintain said reference hydraulic pressure at a constant pre-determined pressure level; (c) sensing the movement of said member at a second point on said member spaced-apart from said first point by means of a hydraulic servo-valve which includes a circular valve housing adapted for unison movement with one of said first and second points on the member and a valve body mounted for rotational movement within said valve housing in unison with the other of said first and second points on the member; (d) directing hydraulic pressure to the member at said second point in response to the sensed movement of said first point on the member relative to said second point on the member; and (e) moving the member at said second point in a direction and for a distance corresponding to the movement of the member at said first point.

Claim 17

A method of maintaining relative positional alignment between two spaced-apart points on a movable member, comprising the steps of: (a) applying a hydraulic reference pressure to said member at a first point thereon; (b) moving said member at said first point to maintain said reference hydraulic pressure at a constant pre-determined pressure level; (c) sensing the movement of said member at a second point on said member spaced-apart from said first point by means of a hydraulic servo-valve which includes a circular valve housing adapted for unison movement with one of said first and second points on the member and a valve body mounted for rotational movement within said valve housing in unison with the other of said first and second points on the member; (d) directing hydraulic pressure to the member at said second point in response to the sensed movement of said first point on the member relative to said second point on the member; and (e) moving the member at said second point in a direction and for a distance corresponding to the movement of the member at said first point.

Claim 20

A method of maintaining relative positional alignment between two spaced-apart points on a rotatable axle, comprising the steps of: (a) applying a hydraulic reference pressure to said axle at a first point thereon; (b) moving said axle at said first point to maintain said reference hydraulic pressure at a constant, pre-determined pressure level; (c) sensing the movement of said axle at a second point on said axle spaced-apart from said first point by means of a hydraulic servo-valve which includes a circular valve housing adapted for unison movement with one of said first and second points on the axle and a valve body mounted for rotational movement within said valve housing in unison with the other of said first and second points on the axle; (d) directing hydraulic pressure to the axle at said second point in response to the sensed movement of said first point of the axle relative to said second point of the axle; and (e) moving the axle at said second point in a direction and for a distance corresponding to the movement of the axle at said first point.

Claim 21

A method of maintaining relative positional alignment between two spaced-apart points on a rotatable axle, comprising the steps of: (a) applying a hydraulic reference pressure to said axle at a first point thereon; (b) moving said axle at said first point to maintain said reference hydraulic pressure at a constant, pre-determined pressure level; (c) sensing the movement of said axle at a second point on said axle spaced-apart from said first point by means of a hydraulic servo-valve which includes a circular valve housing adapted for unison movement with one of said first and second points on the axle and a valve body mounted for rotational movement within said valve housing in unison with the other of said first and second points on the axle; (d) directing hydraulic pressure to the axle at said second point in response to the sensed movement of said first point of the axle relative to said second point of the axle; and (e) moving the axle at said second point in a direction and for a distance corresponding to the movement of the axle at said first point.