US4592590A — Hydraulic lifting mechanism for a chair or the li…

Claim 1

Independent Claim 114 words

A hydraulic lift mechanism for an article of furniture comprising: a base; a support member moveable between extended and retracted positions; a first reservoir containing a two phase working fluid and a hydraulic liquid; a second reservoir supported by said base and containing hydraulic liquid, said second reservoir including a flexible wall and having a variable volume, said second reservoir supporting said support member for movement between said extended and retracted positions in response to variations in said variable volume; conduit means for connecting said first reservoir to said second reservoir to transfer hydraulic liquid therebetween; and control valve means operatively connected in said conduit means for selectively enabling fluid transfer through said conduit.

Claim 2

Dependent Claim 114 words

A hydraulic lift mechanism for an article of furniture comprising: a base; a support member moveable between extended and retracted positions; a first reservoir containing a two phase working fluid and a hydraulic liquid; a second reservoir supported by said base and containing hydraulic liquid, said second reservoir including a flexible wall and having a variable volume, said second reservoir supporting said support member for movement between said extended and retracted positions in response to variations in said variable volume; conduit means for connecting said first reservoir to said second reservoir to transfer hydraulic liquid therebetween; and control valve means operatively connected in said conduit means for selectively enabling fluid transfer through said conduit.

Claim 3

Dependent Claim 42 words

The mechanism of claim 1 wherein said first reservoir includes a dividing wall means for dividing said reservoir into two chambers, the first of said chambers containing said hydraulic liquid and the second of said chambers containing said two phase working fluid.

Claim 4

Dependent Claim 20 words

The mechanism according to claim 1 wherein at least a part of said working fluid is in the liquid state.

Claim 5

Dependent Claim 45 words

The mechanism of claim 1 wherein part of said working fluid is in the liquid state and part of said working fluid is in the gaseous state, the vapor pressure of said gaseous working fluid being substantially constant for all positions of said support member.

Claim 6

Dependent Claim 14 words

The mechanism of claim 2 wherein said dividing wall means comprises a flexible diaphragm.

Claim 7

Dependent Claim 14 words

The mechanism of claim 2 wherein said wall means comprises a flexible rubber diaphragm.

Claim 8

Dependent Claim 19 words

The mechanism of claim 1 wherein said first reservoir is positioned remotely from said base and said second reservoir.

Claim 9

Dependent Claim 26 words

The mechanism of claim 1 wherein said article of furniture comprises a chair and wherein said first reservoir is secured to the seat of said chair.

Claim 10

Dependent Claim 41 words

The mechanism of claim 1 wherein said conduit means is flexible and wherein said control valve means comprises a valve including a cam operable by a lever for selectively pinching off and closing said flexible conduit to prevent liquid flow therethrough.

Claim 11

Dependent Claim 135 words

A hydraulic lifting mechanism for an article of furniture comprising: a base; a support member supported by said base and movable between an extended and a retracted position; a variable volume flexible bag member containing an incompressible hydraulic liquid supported by said base, said support member moving in response to variations in said volume; a fixed volume reservoir including first and second chambers, the respective volumes of said chambers being variable, said first chamber containing hydraulic liquid and connected to said bag member by a hollow conduit; said second chamber containing a compressed two phase working fluid, said compressed working fluid tending to decrease the volume of said first chamber to transfer hydraulic liquid therefrom to said bag member; and control valve means in said conduit for enabling and disabling transfer of said hydraulic liquid.

Claim 12

Dependent Claim 135 words

A hydraulic lifting mechanism for an article of furniture comprising: a base; a support member supported by said base and movable between an extended and a retracted position; a variable volume flexible bag member containing an incompressible hydraulic liquid supported by said base, said support member moving in response to variations in said volume; a fixed volume reservoir including first and second chambers, the respective volumes of said chambers being variable, said first chamber containing hydraulic liquid and connected to said bag member by a hollow conduit; said second chamber containing a compressed two phase working fluid, said compressed working fluid tending to decrease the volume of said first chamber to transfer hydraulic liquid therefrom to said bag member; and control valve means in said conduit for enabling and disabling transfer of said hydraulic liquid.

Claim 13

Dependent Claim 17 words

The mechanism of claim 10 wherein said first and second chambers are divided by a flexible diaphragm.

Claim 14

Dependent Claim 15 words

The mechanism of claim 10 wherein said chambers are divided by a flexible rubber diaphragm.

Claim 15

Dependent Claim 12 words

The mechanism of claim 10 wherein said working fluid is a refrigerant.

Claim 16

Dependent Claim 11 words

The mechanism of claim 10 wherein said working fluid is Freon.

Claim 17

Dependent Claim 30 words

The mechanism of claim 10 wherein said article of furniture comprises a chair and wherein said fixed volume reservoir is secured to the bottom of the seat of said chair.

Claim 18

Dependent Claim 38 words

The mechanism of claim 10 wherein said conduit means is flexible and wherein said control valve means includes a cam member operable by a lever for selectively pinching and closing said flexible conduit to prevent fluid flow therethrough.

Claim 19

Dependent Claim 123 words

A chair height adjustment mechanism comprising: a base member; a first reservoir supported on said base, said reservoir including a flexible wall member and containing an incompressible hydraulic liquid; a vertically movable support member supported by said first reservoir; a chair seat supported on said support member and vertically movable therewith; a second reservoir having a fixed volume and divided into first and second chambers by a flexible diaphragm, said first chamber being sealed and including a compressed two phase working fluid, said second chamber containing said hydraulic liquid; a hollow conduit means interconnecting said second chamber and said first reservoir for transfer of liquid therebetween; and control valve means connected in said conduit means for selectively enabling liquid flow through said conduit.

Claim 20

Dependent Claim 123 words

A chair height adjustment mechanism comprising: a base member; a first reservoir supported on said base, said reservoir including a flexible wall member and containing an incompressible hydraulic liquid; a vertically movable support member supported by said first reservoir; a chair seat supported on said support member and vertically movable therewith; a second reservoir having a fixed volume and divided into first and second chambers by a flexible diaphragm, said first chamber being sealed and including a compressed two phase working fluid, said second chamber containing said hydraulic liquid; a hollow conduit means interconnecting said second chamber and said first reservoir for transfer of liquid therebetween; and control valve means connected in said conduit means for selectively enabling liquid flow through said conduit.

Claim 21

Dependent Claim 19 words

The mechanism of claim 17 wherein at least a part of said working fluid is in the liquid state.

Claim 22

Dependent Claim 47 words

The mechanism of claim 17 wherein a part of said working fluid is in the liquid state and the remainder of said working fluid is in the gaseous state, the vapor pressure of said gaseous working fluid being substantially constant for all positions of said support member.

Claim 23

Dependent Claim 14 words

The mechanism according to claim 17 wherein said flexible diaphragm is comprised of rubber.

Claim 24

Dependent Claim 21 words

The mechanism according to claim 17 wherein said second volume reservoir is positioned remotely from said base and said first reservoir.

Claim 25

Dependent Claim 42 words

The mechanism according to claim 17 wherein said hollow conduit means is flexible and wherein said control valve means includes a rotatable cam member operable by a lever for selectively pinching off and closing said flexible conduit to prevent liquid flow therethrough.

Claim 26

Dependent Claim 48 words

The mechanism of claim 22 and including a spring bias means for biasing said cam member into said conduit closing position said lever being selectively operable against the urging bias force of said spring member to open said conduit and to permit selective adjustment of the chair height.

Claim 27

Dependent Claim 11 words

The mechanism of claim 16 wherein said working fluid is refrigerant.

Claim 28

Dependent Claim 11 words

The mechanism of claim 24 wherein said working fluid is freon.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-06-02	1989-12-02	1990-06-03	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-06-02	1993-12-02	1994-06-03	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-06-02	1997-12-02	1998-06-03	$7700.00	Window Closed / Lapsed

Hydraulic lifting mechanism for a chair or the like using a two phase working fluid

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