Hydraulic chair height adjustment mechanism
AssigneeSteelcase Inc.
InventorsLarry DeKraker, Richard P. Thorn
Life of this patent
Estimating the term…
Abstract
An adjustment mechanism for adjusting the height of a chair seat, table top or the relative position of other items includes an outer support tube and a telescoping, column tube subassembly. The column tube subassembly includes an inner support tube, a cylinder and a piston and piston rod subassembly. The piston rod is connected to the piston at one end and to the outer support tube at the other end. An elastomeric sleeve surrounds the cylinder. A valve controls flow of hydraulic fluid from the interior of the cylinder to and from an expandable chamber defined by the elastomeric sleeve. The piston snap-fits onto the piston rod and allows rotation of the column tube subassembly with respect to the outer support tube. A shock-absorbing element is disposed in the cylinder.
Claims73
An adjustable column assembly, said assembly comprising:
- an outer support tube having a lower end and an open, upper end;
- a column tube subassembly telescopingly disposed within said outer support tube, said subassembly including:
- an inner support tube;
- a cylinder within said inner support tube;
- a piston within said cylinder;
- a piston rod connected to said piston at one end and to said outer support tube at its other end so that said cylinder may move into and out of said outer support tube on said piston;
- an elastomeric sleeve surrounding said cylinder, said sleeve and said cylinder defining an expandable chamber having an inlet;
- valve means between said cylinder and the inlet to said expandable chamber for controlling the flow of fluid between the cylinder and the expandable chamber so that the flow rate from the cylinder to the chamber is different than the flow rate from the chamber to the cylinder.
A height adjustment device for raising, lowering and locking a chair seat and the like in position with respect to a base, said device comprising:
- a support tube;
- a cylinder disposed within said support tube, said tube and cylinder defining an annular space;
- a piston disposed within said cylinder;
- a rod connected to said piston at one end and extending from said cylinder, said piston and cylinder being rotatable on said rod;
- an expandable chamber within said annular space for receiving and pressuring a fluid;
- passage means between said cylinder and said chamber for defining a passage and allowing flow of fluid between the cylinder and chamber as said piston moves within said cylinder;
- and
- flow control means within said passage for controlling flow of fluid between the cylinder and expandable chamber, said flow control means allowing flow between said cylinder to said chamber at different rates depending on the direction of flow.
A hydraulic actuator comprising:
- a cylinder having a first end and a second end;
- a closure disposed within said second end, said closure defining a rod bore;
- a rod extending into said cylinder through said rod bore;
- a piston on said rod, said piston being within said cylinder;
- an expandable, elastomeric sleeve surrounding said cylinder, said sleeve defining an inlet;
- a passage connecting said sleeve inlet with the cylinder;
- and
- valve means within said passage for controlling flow of a hydraulic fluid from said cylinder to said sleeve inlet, said valve means being moveable from a closed position to an open position and allowing flow from the cylinder to the sleeve inlet at a rate less than the rate of flow from said sleeve inlet to said cylinder.
A piston/cylinder actuator comprising:
- an elongated cylinder;
- a bushing disposed in an end of said cylinder, said bushing defining a central bore;
- an elongated rod extending through said bore and into said cylinder, said rod defining a circumferential groove adjacent an end thereof within said cylinder;
- and
- a piston, said piston having an expandable skirt and a retention bead thereon, said piston fitting over said rod with said bead disposed in said groove and said piston being held captive on said rod by contact with the inner surface of said cylinder.
A hydraulic actuator, comprising:
- a cylinder including incompressible fluid therein;
- a piston disposed within said cylinder;
- a rod connected to said piston;
- a valve on said cylinder for controlling flow of the incompressible fluid into and out of the cylinder;
- and
- a compressible shock absorber disposed within said cylinder and immersed in the incompressible fluid such that said incompressible fluid compresses the compressible shock absorber volumetrically when the incompressible fluid is loaded.
An adjustable column assembly for a chair or the like comprising:
- an outer support tube having an open end;
- and
- a column tube subassembly telescopingly disposed within said outer support tube, said subassembly adapted to move into and out of said outer support tube, said subassembly including:
- an inner support tube;
- a cylinder within said inner support tube;
- a piston within said cylinder;
- a piston rod connected to said piston at one end so that said cylinder may move into and out of said outer support tube on said piston;
- an elastomeric sleeve surrounding said cylinder, said sleeve and said cylinder defining an expandable chamber having an inlet, said sleeve having a preload force capable of extending said cylinder to its outermost position when said chair is unoccupied;
- and
- valve means between said cylinder and the inlet to said expandable chamber for controlling the flow of fluid between the cylinder and the expandable chamber.
Dependencies are inferred from the claim text.