EP0021813A2
Expired / Lapsed
EP
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Height adjustable chair base
Assignee: Steelcase Inc
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Filing: 1980-06-20
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Granted: —
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Expires: 2000-06-20
Abstract
Abstract An easy to assemble, height adjustable chair base in vhich a column (20) telescopically received within a hub tube 10) includes a spring (40) and nut (50) located within the bottom of the column and carried on a threaded post (80) ixedly secured and projecting upwardly within the hub tube 10). A spring housing (30) is rotatably carried within the column (20) and the top abuts against an abutment shoulder 21) located within the column. The spring (40) is located vithin a spring housing (30) and both the spring and spring lousing bear down on a washer (20) which in turn bears down on the nut (50). The column includes detent means (60) ocated on the column below the nut which disengages the put when a person sits on the chair, but which is biased upwardly towards engagement with the nut by the action of he spring when the chair is unoccupied. When the chair is unoccupied, rotation of the chair will cause the nut to rotate upwardly or downwardly on the threaded post
Inventors
- 👤 Duane Milo Beukema
- 👤 Jack Richard Knoblauch
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 09:27
CPC Classifications
A; A47; A47C; A47C3/00; A47C3/20; A47C3/24; A47C3/18
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
228 words
A height adjustable chair base having a hub tube (10), a seat column (20) telescopically positioned within the hub tube and being operably carried on a nut (50) which is located within the column and which is threaded on an externally threaded post (80) located within the hub tube, characterised in that: the base comprises: abutment means (22) located within the column above the nut, and spring means (40) positioned between the abutment means and the nut and abuting both,whereby the column is biased upwardly relative to the nut; the nut includes detent-receiving means (54) opening towards the underside of the nut; the column extends downwardly outside the nut to a point below the detent-receiving means on the nut; the column including detent means (60) located below the detent receiving means on the nut; the threaded post being fixed against rotation within the hub tube; the spring means being sufficiently soft that it compresses when a chair mounted on the column is occupied by a person, but being sufficiently stiff that when the chair is unoccupied, the spring means biases the column upwardly and biases the detent means into engagement with the detent receiving means on the nut whereby, when the chair seat and column are rotated, the nut rotates on the threaded post to adjust the chair upwardly or downwardly depending on the direction of rotation thereof.
Claim 2
Dependent Claim
228 words
A height adjustable chair base having a hub tube (10), a seat column (20) telescopically positioned within the hub tube and being operably carried on a nut (50) which is located within the column and which is threaded on an externally threaded post (80) located within the hub tube, characterised in that: the base comprises: abutment means (22) located within the column above the nut, and spring means (40) positioned between the abutment means and the nut and abuting both,whereby the column is biased upwardly relative to the nut; the nut includes detent-receiving means (54) opening towards the underside of the nut; the column extends downwardly outside the nut to a point below the detent-receiving means on the nut; the column including detent means (60) located below the detent receiving means on the nut; the threaded post being fixed against rotation within the hub tube; the spring means being sufficiently soft that it compresses when a chair mounted on the column is occupied by a person, but being sufficiently stiff that when the chair is unoccupied, the spring means biases the column upwardly and biases the detent means into engagement with the detent receiving means on the nut whereby, when the chair seat and column are rotated, the nut rotates on the threaded post to adjust the chair upwardly or downwardly depending on the direction of rotation thereof.
Claim 3
Dependent Claim
62 words
A chair base according to Claim 1 wherein the spring means includes a housing (30) located within the column and rotatable with respect thereto, and a spring (40) located within the housing; the housing being fixed against rotation with respect to the threaded post but being slidable vertically thereon; and the abutment means of the column being rotatably positioned on the housing.
Claim 4
Dependent Claim
39 words
A chair base according to Claim 1 or 2 wherein the abutment means comprises: the column being lanced inwardly (21) and a shoulder washer (22) being positioned within the column and resting against the lanced portions of the column.
Claim 5
Dependent Claim
46 words
A chair base according to Claim 1, 2 or 3 which includes means (70, 72, 53) biasing the nut against rotation with respect to the post when the spring is compressed by the weight of a person seated in a chair mounted on the chair base.
Claim 6
Dependent Claim
65 words
A chair base according to Claim 4 in which; the base means biasing the nut against rotation with respect to the post when the spring is compressed comprises a washer (70) corrugated (72) at least on the bottom surface thereof and located between the spring means and the nut; the nut including a corrugated upper surface (53) mated with corrugated bottom surface of the washer.
Claim 7
Dependent Claim
49 words
A chair base according to any one of Claims 1 to 5 wherein the nut (50) comprises a threaded sleeve (51) having an upper radial flange (52) projecting radially outwardly therefrom, the corrugated upper surface of the nut comprising corrugated deviations (53) in the top surface of the flange.
Claim 8
Dependent Claim
99 words
A chair base according to any one of Claims 1 to 6 in which: detent receiving means (54) are located on the underside of the flange, the detent receiving means and the detent means (64) combine to form a deeper mating engagement than said corrugation (53) in the upper surface of the flange and the corrugation (72) on the washer (70) whereby the interaction of detent means and the detent receiving means will override interaction of the biasing washer and the nut, and the nut will rotate with the column when the detent means engage the detent receiving means.
Claim 9
Dependent Claim
47 words
A chair base according to any one of Claims 1 to 7 in which the detent means comprises a ring (60) secured in the bottom of the column, the ring including upwardly protruding detent projections (64); the detent receiving means (54) comprising mating depressions in the nut.
Claim 10
Dependent Claim
36 words
A chair base according to Claim 8 wherein the detent ring includes prongs (62) projecting laterally therefrom, the column including apertures receiving the prongs whereby the ring will snap fit into the bottom of the column.
Claim 11
Dependent Claim
62 words
A chair base according to any one of Claims 1 to 9 which includes quick fastening means (84) for securing the threaded post.to the bottom of the hub tube whereby the seat column, the spring means, the nut, the detent means and the threaded spindle can be assembled as a single sub-assembly and then readily inserted into and secured.to the hub tube.
Claim 12
Dependent Claim
82 words
A chair base according to any one of Claims 2 to 10 wherein the spring housing includes a collar (33) at the upper end thereof surrounding the threaded post, the collar including a projection (34) projecting inwardly therefrom, the threaded post including a vertical slot (81) extending generally from the top to the bottom thereof, the projection extending into the vertical slot whereby the spring housing is fixed against rotation with respect to the threaded post which slides up and down thereon.
References Cited (Backward Citations)
No citation records indexed.
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