Chairs and seats – Movable back – Tiltable
Patent
1986-03-10
1987-09-15
Dorner, Kenneth J.
Chairs and seats
Movable back
Tiltable
297320, 297355, A47C 1024
Patent
active
046935142
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a chair as defined in the preamble of claim 1.
In a known chair of this type (DE-PS No. 2,927,377) the clamping device is axially supported at the seat or the seat carrier at which the lever for shifting the friction lock is also mounted. The laminar friction lock is controllable with the aid of the twin-arm lever design and the cooperation of tensionable spring washers. The friction lock is here produced and maintained by the spring washers. Such a clamping principle is therefore relatively expensive to produce. To release the friction lock, the spring washers are compressed by means of the actuation lever until the friction lock is released. This requires a relatively large path for the pivot movement of the lever.
A chair is also known which has a comparable clamping device (DE-OS No. 2,335,586, FIG. 2a) where the laminar friction lock is established without the aid of spring means but with the aid of an eccentric. In this case, however, the clamping device, which is asymmetrically arranged with respect to the plane of symmetry of the chair, is likewise axially supported at the seat or the seat carrier. Since such a clamping device requires that the eccentric be self-locking, the rise of the eccentric curve, when the eccentric engages at the frontal face of the clamping bolt, is of necessity relatively small. This small rise requires, on the one hand, less operating resistance, on the other hand, a relatively long pivot path for actuation of the eccentric.
In the known clamp mechanisms, the eccentric is always supported by a stationary portion of the chair. Therefore, the axial movement required to establish or release the laminar friction lock is effected exclusively by the axial thrust of the nonstationary (driving) part of the eccentric which must be designed for a correspondingly long thrust.
It is the object of the invention to modify a seat of the above-mentioned species so that, with favorable conditions for economic mass production, the pivot path of the lever for operating the eccentric is shortened and thus manual control the clamping device is facilitated.
This is accomplished by the invention with the features defined in the characterizing portion of claim 1.
In such a configuration, the relative movement between the clamping bolt and the adjacent friction lock discs produced by actation of the eccentric is converted into a simultaneous, but oppositely directed axial movement of the friction lock discs and laminae disposed on one side of the plane of symmetry a--a and the friction lock discs and laminae disposed on the other side of this plane of symmetry. The friction lock discs and laminae on the side of the eccentric are pushed toward the plane of symmetry. The friction lock discs and laminae disposed on the other side of the plane of symmetry, however, are pulled toward this plane of symmetry. This results in a shorter pivot path for the eccentric whose pivot axis is fixed to the clamping bolts and whose eccentric curves (eccentric discs) lie at the packet of friction lock discs. An approximately symmetrical construction of the clamping device arranged symmetrically to the plane of symmetry is beneficial for mass production.
The invention will be described below with reference to three embodiments and the drawing.
It is shown in:
FIG. 1, a top view of the stationary seat of the chair with the seat shell removed and an adjustable-inclination support for the back rest;
FIG. 2, a bottom view of the seat,
FIG. 3, an enlarged sectional view along line III--III of FIG. 1 of the seat according to FIGS. 1, 2;
FIG. 3a, an enlarged sectional view along line IIIa--IIIa of FIG. 1 of the seat according to FIGS. 1, 2;
A further embodiment [is shown in] FIGS. 4-6, 6a.
FIG. 4, is a top view of the seat without set shell of the chair having an adjustable-inclination support for the back rest.
FIG. 5 is a bottom view of the seat according to FIG. 4.
FIG. 6 is a sectional view along line VI--VI of FIG. 4 of the seat of FIG. 4.
FIG. 6a is a sectional view along line VIa--VIa of FIG.
REFERENCES:
patent: 2903046 (1959-09-01), Repaich
patent: 3989297 (1976-11-01), Kerstholt
Binder Mark W.
Dorner Kenneth J.
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