Chair height adjustment mechanism
OwnerJames M. Janninventor
Life of this patent
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Abstract
A chair height mechanism in which a threaded nut (30) is threaded onto a threaded spindle (16) and a hub tube (18) supports the spindle through a clutch comprising a locking tube (34) secured to the nut (30) and having lower tapered portion (36), and a cylindrical liner (46) secured to the hub tube and having an upper tapered outer surface (48) which mates with the cylindrical liner (46) inner surface. A compression spring (42) biases the tapered surfaces of the liner (46) and the locking tube (34) into engagement.
Claims15
In a chair height adjustment mechanism wherein a nut is threaded onto a threaded spindle, a clutch selectively couples the nut to a hub tube for adjusting the axial height of the spindle with respect to the hub tube and means bias the clutch into engagement relationship between the hub tube and the nut so that the spindle is adjustable with respect to the hub tube when a chair attached to the spindle is unoccupied and the clutch is disengaged so that the relationship between the hub tube and the spindle is not adjustable when the chair is unoccupied;
- the improvement in the clutch which comprises:
- a cylindrical locking tube secured to said nut and extending downwardly thereof, a portion of said locking tube forming an inwardly tapering locking surface beneath said nut;
- said hub tube including a cylindrical wedge member telescopingly received within said locking tube, said wedge member having a flared outer surface complementary to said tapered locking surface;
- wherein slight upward movement of said wedge member with respect to said locking tube disengages said clutch and said clutch is engaged by slight downward movement of said wedge member with respect to said locking tube.
Dependencies are inferred from the claim text.