US3941403A — Hydro-pneumatic suspension unit

Claim 1

Independent Claim 342 words

A hydro-pneumatic self-levelling suspension unit for an automotive vehicle comprising first and second cylindrical members which are telescopically connected together and which are axially movable relative to each other, self-levelling valve means disposed in said first cylindrical member and having a first position operative to direct fluid pressure into the first and second cylindrical members for causing the first and second cylindrical members to axially move relative to each other in directions to axially extend the suspension unit and a second position operative to discharge the fluid pressure from the first and second cylindrical members for causing the first and second cylindrical members to axially move relative to each other in directions to axially contract the suspension unit, resilient biasing means disposed in the first cylindrical member and engaging said valve means for biasing the valve means toward an equilibrium position between said first and second positions of the valve means thereby holding the suspension unit in a balanced condition, hydro-pneumatic spring means operative to compensate for fluctuations in the fluid pressure in said first cylindrical member, valve actuating means disposed in said second cylindrical member and engaging said resilient biasing means, said valve actuating means being stepwise extensible in an axial direction of said cylindrical member between a fully contracted length and a fully extended length for actuating said valve means through said resilient biasing means into said first position responsive to extension of said valve actuating means and into said second position responsive to contraction of the valve actuating means, said valve actuating means being biased toward said fully contracted length partly by said resilient biasing means and partly by the fluid pressure in the first and second cylindrical members, fluid supply means having a plurality of operative positions for supply working fluid to the valve actuating means and causing the valve actuating means to be selectively stepwise extended or contracted between said fully contracted length and said fully extended length, and manually-operated control means for manually actuating the fluid supply means selectively into any of said operative positions thereof.

Claim 2

Dependent Claim 342 words

A hydro-pneumatic self-levelling suspension unit for an automotive vehicle comprising first and second cylindrical members which are telescopically connected together and which are axially movable relative to each other, self-levelling valve means disposed in said first cylindrical member and having a first position operative to direct fluid pressure into the first and second cylindrical members for causing the first and second cylindrical members to axially move relative to each other in directions to axially extend the suspension unit and a second position operative to discharge the fluid pressure from the first and second cylindrical members for causing the first and second cylindrical members to axially move relative to each other in directions to axially contract the suspension unit, resilient biasing means disposed in the first cylindrical member and engaging said valve means for biasing the valve means toward an equilibrium position between said first and second positions of the valve means thereby holding the suspension unit in a balanced condition, hydro-pneumatic spring means operative to compensate for fluctuations in the fluid pressure in said first cylindrical member, valve actuating means disposed in said second cylindrical member and engaging said resilient biasing means, said valve actuating means being stepwise extensible in an axial direction of said cylindrical member between a fully contracted length and a fully extended length for actuating said valve means through said resilient biasing means into said first position responsive to extension of said valve actuating means and into said second position responsive to contraction of the valve actuating means, said valve actuating means being biased toward said fully contracted length partly by said resilient biasing means and partly by the fluid pressure in the first and second cylindrical members, fluid supply means having a plurality of operative positions for supply working fluid to the valve actuating means and causing the valve actuating means to be selectively stepwise extended or contracted between said fully contracted length and said fully extended length, and manually-operated control means for manually actuating the fluid supply means selectively into any of said operative positions thereof.

Claim 3

Dependent Claim 221 words

A hydro-pneumatic self-levelling suspension unit, in which said valve actuating means comprise a plurality of plungers which are axially arrayed substantially in line with each other in the second cylindrical member and which are engageable end-to-end with each other, each of the plungers being axially movable between a first extreme position remotest from said self-levelling valve means and a second extreme position closest to the valve means, the plunger located closest to the valve means being connected to said resilient biasing means, said fully contracted length of the valve actuating means being achieved with all of the plungers held in the respective first extreme positions thereof and said fully extended length of said valve actuating means being achieved with the plunger remotest from said valve means held in the first extreme position thereof and the plunger closest to the valve means held in the second extreme position thereof, the plunger closest to the valve means being stepwise moved between the first and second extreme positions thereof by the fluid pressure developed in the valve actuating means by the working fluid directed to the actuating means from said fluid supply means, the working fluid from the fluid supply means being applied to at least one of the plungers which is selected depending upon the operative position selected in the fluid supply means.

Claim 4

Dependent Claim 221 words

A hydro-pneumatic self-levelling suspension unit, in which said valve actuating means comprise a plurality of plungers which are axially arrayed substantially in line with each other in the second cylindrical member and which are engageable end-to-end with each other, each of the plungers being axially movable between a first extreme position remotest from said self-levelling valve means and a second extreme position closest to the valve means, the plunger located closest to the valve means being connected to said resilient biasing means, said fully contracted length of the valve actuating means being achieved with all of the plungers held in the respective first extreme positions thereof and said fully extended length of said valve actuating means being achieved with the plunger remotest from said valve means held in the first extreme position thereof and the plunger closest to the valve means held in the second extreme position thereof, the plunger closest to the valve means being stepwise moved between the first and second extreme positions thereof by the fluid pressure developed in the valve actuating means by the working fluid directed to the actuating means from said fluid supply means, the working fluid from the fluid supply means being applied to at least one of the plungers which is selected depending upon the operative position selected in the fluid supply means.

Claim 5

Dependent Claim 220 words

A hydro-pneumatic self-levelling suspension unit as set forth in claim 2, in which said valve actuating means further comprise cylindrical wall means fast on said second cylindrical member and defining a plurality of axial bores which are axially arrayed substantially in line with each other in said second cylindrical member and in which said plungers are respectively axially slidable and lateral wall means including an apertured intermediate wall separating axially adjacent two of the axial bores from each other, a lateral end wall forming part of the second cylindrical member and defining an axial end of the axial bore located remotest from said self-levelling valve means and an apertured end wall defining an axial end of the axial bore located closest to said valve means, said walls providing stop means defining said first and second extreme positions of said plungers, said apertured intermediate wall being formed with an opening in which the plunger in remoter one of the adjacent two axial bores to said valve means is axially slidably received and engageable with the plunger in the other of the adjacent two axial bores, said apertured end wall being formed with an opening through which the plunger in the axial bore located closest to the valve means axially projects toward the valve means and connected to said resilient biasing means.

Claim 6

Dependent Claim 162 words

A hydro-pneumatic self-levelling suspension unit as set forth in claim 3, in which said valve actuating means further comprise wall portions formed with fluid passageways leading from said fluid supply means and including a first fluid passageway terminating at the axial end of the axial bore remotest from said self-levelling valve means for moving the plunger in the axial bore from the first extreme position to the second extreme position when the working fluid is directed into the first fluid passageway, and at least one second fluid passageway terminating intermediate between the axially adjacent two of said axial bores for moving the plunger in the remoter one of the two axial bores from the valve means from the second extreme position to the first extreme position thereof and simultaneously moving the plunger in the other of the two axial bores from the first extreme position toward the second extreme position thereof when the working fluid is directed into the second fluid passageway.

Claim 7

Dependent Claim 165 words

A hydro-pneumatic self-levelling suspension unit as set forth in claim 4, in which said self-levelling valve means comprise a valve member axially movable in said first cylindrical member between a first position directing the fluid pressure into the first and second cylindrical members and a second axial position discharging the fluid pressure from the first and second cylindrical members and in which said resilient biasing means comprise a first preload spring urging the valve member toward the first axial position thereof and a second preload spring urging the valve member toward the second axial position thereof against an opposing force of the first preload spring, said first and second preload springs being balanced with each other for urging the valve member toward an equilibrium position providing said equilibrium position of said valve actuating means, said first preload spring being seated at one end on said valve member and connected at the other end to the plunger in the axial bore closest to said valve member.

Claim 8

Dependent Claim 67 words

A hydro-pneumatic self-levelling suspension unit as set forth in claim 4, in which said fluid supply means comprise a source of fluid under pressure, and a control valve having a first operative position directing the working fluid into said first fluid passageway from the fluid source and a second operative position directing the working fluid to said at least one second fluid passageway from the fluid source.

Claim 9

Dependent Claim 171 words

A hydro-pneumatic suspension unit as set forth in claim 6, in which said manually operated control means comprise an elongate control member axially movable in an axial bore formed in a stationary member and formed with a plurality of recess corresponding in number to the number of operative positions of said fluid supply means and accordingly to the number of said plungers, a plurality of locking members received in said stationary member and engageable with said control member through any one of said recesses depending upon the axial position of the control member relative to the locking member, biasing means for urging the locking member against the control member and holding the locking member in locking engagement with the control member when the locking member is received in any of said recesses, and a control lever operatively connected to said control member and adapted to be manually operated to drive said control member to axially moved into an axial position having any of said recesses located to receive said locking member.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1979-03-02	1979-09-01	1980-03-02	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1983-03-02	1983-09-01	1984-03-02	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1987-03-02	1987-09-01	1988-03-02	$7700.00	Window Closed / Lapsed

Hydro-pneumatic suspension unit

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