Pressure balanced hydrostatic slip bearing used in a guide and restraint system

Claim 2

A pressure balanced hydrostatic slip bearing comprising means forming a movable wall chamber having a wall movable in a direction of expansion in response to fluid pressure in said chamber, means on the exterior of said movable wall forming a hydrostatic bearing for a member to be guided, a source of fluid under pressure, means including flow sensitive orifice means connecting said source of fluid under pressure to said chamber, drain orifice means leading from said chamber and being separate from the connection of said flow sensitive orifice means to said chamber, said drain orifice means including a portion responsive to movement of said movable wall whereby the size of said drain orifice means changes when said movable wall moves from a reference position established by flow of fluid under pressure to said chamber and through said drain orifice means.

Claim 3

The pressure balanced hydrostatic slip bearing of claim 1 wherein said drain orifice means includes a movable member biased in the direction of expansion of said movable wall means, said movable member extending to establish the reference position of said movable wall, and said movable member being retractable against the action of said bias means when engaged and moved by said movable wall as said movable wall moves in opposite dIrection from its direction of expansion.

Claim 4

The slip bearing of claim 1 wherein said hydrostatic bearing is formed between said movable wall and a surface to be guided, a seal mounted on the exterior of said movable wall in position to face and engage a surface to be guided, said seal defining an enclosed area, and means opening from said chamber through said movable wall in the area enclosed by said seal, said seal being operable to seal on a surface to be guided when said chamber is under fluid pressure.

Claim 5

The slip bearing of claim 3 and spring means acting to move said movable wall in its expansion direction to urge said seal toward a surface to be guided.

Claim 6

The slip bearing of claim 3 wherein said movable wall is moved outwardly by fluid pressure acting against an effective wall area within said chamber and wherein said enclosed area is less than said effective area.

Claim 7

The slip bearing of claim 3 wherein said seal comprises a first member adapted to slidably engage a surface to be guided, and a second resilient member positioned between said first member and said movable wall, said movable wall comprising a movable member slidably mounted on said chamber, and means cooperating between said movable member and said chamber to permit said movable member to swivel with respect to said chamber a limited amount.

Claim 8

The slip bearing of claim 1 wherein said slip bearing is used in combination to form a restraint system for a test table having oppositely facing guide surfaces, said means forming a hydrostatic bearing engaging one guide surface of said table, and means on an opposite guide surface of said table exerting a substantially constant force in opposite direction from the direction of expansion of said movable wall.

Claim 9

The combination of claim 7 wherein said means exerting a constant force comprises a fluid pressure actuated piston, a source of fluid under substantially constant pressure open to said piston, and inlet flow restrictor means to limit the rate of fluid flow between said piston and said source of fluid under substantially constant pressure.

Claim 10

A restraint system for guiding movement of an object in opposite directions along a direction axis, a first guide means exerting a substantially constant force through the range of travel of said first guide means, means between said first guide means and said object oriented so said constant force tends to move said object in a first direction substantially perpendicular to said direction axis throughout the travel of said first guide means, and second guide means, means acting between said second guide means and said object whereby said second guide means engages said object and opposes and balances the force from said first guide means with the object in a reference position, said second guide means including control means to change the force exerted by said second guide means on said object when said object moves from its reference position in a direction having a component perpendicular to the direction axis to thereby tend to restore said object to its reference position with the forces on the object from the first and second guide means balanced.

Claim 11

A restraint system for guiding movement of an object in opposite directions along a direction axis, a first guide means exerting a substantially constant force through the range of travel of said first guide means, means between said first guide means and said object oriented so said constant force tends to move said object in a first direction substantially perpendicular to said direction axis throughout the travel of said first guide means, and second guide means, means acting between said second guide means and said object whereby said second guide means engages said object and opposes and balances the force from said first guide means with the object in a reference position, said second guide means including control means to change the force exerted by said second guide means on said object when said object moves from its reference position in a direction having a component perpendicular to the direction axis to thereby tend to restore said object to its reference position with the forces on the object from the first and second guide means balanced.

Claim 12

The combination as specified in claim 9 wherein said second guide means comprises a fluid actuated cylinder, and said control means includes means operative to reduce the pressure in said fluid actuated cylinder when said object moves toward said first guide means from said reference position.

Claim 13

The combination as specified in claim 9 wherein said second guide means comprises a hydraulic cylinder creating an equal and opposite force to said first guide means when said object is in said reference position, and said control means includes an orifice in said cylinder providing a fluid bleed path from said cylinder which increases in rate of bleed as said object moves in a direction perpendicular to said direction axis and toward said first guide means from said reference position.

Claim 14

The combination as specified in claim 11 whErein said orifice reduces in size to tend to retain fluid in said hydraulic cylinder of said second guide means when said object moves in a direction perpendicular to said direction axis toward said second guide means from said reference position.

Claim 15

The combination as specified in claim 9 wherein said object comprises a table having substantially parallel side surfaces, and said first and second guide means include surface portions comprising bearing means engaging said side surfaces of said table to permit sliding movement of said table past said first and second guide means along said direction axis, and means comprising a hydrostatic bearing area between said first and second guide means and said respective side surfaces.

Claim 16

The combination as specified in claim 9 wherein said second guide means comprises a fluid actuated cylinder having a piston movable between first and second positions, said piston being positioned at an intermediate location between said first and second positions with the object in said reference position, said control means including means to supply fluid under pressure to said fluid actuated cylinder including a fluid pressure source, a flow sensitive metering means in circuit between said source and said fluid actuated cylinder, for reducing fluid pressure between said source and said cylinder at a desired rate of fluid flow, and a variable size bleed orifice leading from said fluid actuated cylinder, said bleed orifice being changeable in size upon movement of said piston of said second guide means as said object moves from its reference position.

Claim 17

The combination as specified in claim 14 wherein said first guide means comprises a separate fluid pressure cylinder, and a regulated fluid pressure supply means connected to said separate fluid pressure cylinder.

Claim 18

A guide assembly for use with a movable test table, said test table having lateral side sliding guide surface means, lateral guide means for said table comprising first force generating means and a fluid cylinder on opposite lateral sides of said table respectively, means to move said table in a path as guided by said lateral guide means, said first force generating means being urged against said guide surface means on one side of said table under a substantially constant preselected first force in a lateral direction, said fluid cylinder including a piston and engaging the guide surface means on a second side of said table, means supplying pressure to said piston to urge said piston and table in an opposite direction from the first force under a substantially equal force to the first force to guide said table to an equilibrium position, said fluid cylinder including an orifice leading from the cylinder to drain, means controlling the size of said orifice to provide for a flow through said cylinder when the force exerted by said piston in a normal piston position is equal to the first force to hold said table at equilibrium, a source for fluid under pressure, means providing a flow sensitive pressure drop from said source of fluid under pressure to said fluid cylinder, and said means controlling the size of said orifice being sensitive to the position of said piston so that as said piston moves from its normal position said bleed orifice changes to control the pressure acting on said piston to reestablish said table at an equilibrium position controlled by the first force provided from said first force generating means.

Claim 19

A guide assembly for use with a movable test table, said test table having lateral side sliding guide surface means, lateral guide means for said table comprising first force generating means and a fluid cylinder on opposite lateral sides of said table respectively, means to move said table in a path as guided by said lateral guide means, said first force generating means being urged against said guide surface means on one side of said table under a substantially constant preselected first force in a lateral direction, said fluid cylinder including a piston and engaging the guide surface means on a second side of said table, means supplying pressure to said piston to urge said piston and table in an opposite direction from the first force under a substantially equal force to the first force to guide said table to an equilibrium position, said fluid cylinder including an orifice leading from the cylinder to drain, means controlling the size of said orifice to provide for a flow through said cylinder when the force exerted by said piston in a normal piston position is equal to the first force to hold said table at equilibrium, a source for fluid under pressure, means providing a flow sensitive pressure drop from said source of fluid under pressure to said fluid cylinder, and said means controlling the size of said orifice being sensitive to the position of said piston so that as said piston moves from its normal position said bleed orifice changes to control the pressure acting on said piston to reestablish said table at an equilibrium position controlled by the first force provided from said first force generating means.

Claim 20

The combination as specified in claim 16 wherein said first force generating means comprises a separate fluid pressure actuated cylinder having a piston, means to supply fluid under a substantially constant pressure to said separate fluid pressure actuated cylinder, and flow restrictor means between said separate fluid pressure actuated cylinder and said means to supply a substantially constant pressure.

Claim 21

The combination as specified in claim 16 wherein said orifice is formed between a surface movable with said piston and a drain port, said Drain port being defined in a separate member, said separate member being attached to a separate movable piston mounted on said cylinder, and means to supply a separate regulated pressure to actuate said separate movable piston.

Claim 22

The combination of claim 16 and means forming a hydrostatic bearing between said fluid cylinder and the guide surface means on a second side of said table comprising resiliently mounted seal means between said guide surface means on a second side of said table and said fluid cylinder, encompassing a hydrostatic bearing area, and passageway means opening from said fluid cylinder to the area encompassed by said seal means.

Claim 23

The combination of claim 16 wherein said piston and cylinder include cooperating part cylindrical wall means to permit angular movement between said cylinder and piston.