US2764223A - Revolvable chair - Google Patents

Description

Sept. 25, 1956 K. MISCHKE REVOLVABLE CHA-IR Filed Aug. 24, 1954 Fig 1 Fig.3

United States Patent O 2,764,223 REVOLVABLE CHAIR Karl Mischke, Zurich, Switzerland Application August 24, 1954, Serial No. 451,810 Claims priority, application Switzerland August 25, 1953 3 Claims. (Cl. 155-95) The present invention relates to a swivel or revolving chair, which is characterized by the provision of a locking device, arranged between the seat and the support for the latter, and adapted to lock the seat against rotation when the latter is not loaded and to be automatically released when the seat is loaded.

The prime object of the invention is to obtain a swivel chair which is freely revolvable when in use, but the seat of which is immediately locked in its last angular position with respect to the support when the user of the chair stands up.

According to a preferred embodiment of the invention there is provided at least one locking pin connected with the seat and adapted to co-operate with one of a ring of stop grooves provided at the support for the seat, wherein spring means arranged between the seat and its support are adapted to maintain the said locking pin in engagement with one of the stop grooves as long as the seat is not loaded, while said locking pin comes out of engagement with said groove as soon as the seat is loaded thereby permit-ting free revolving of the latter with respect to its support.

Other features and advantages of the invention will become apparent from the description now to follow, of a preferred embodiment thereof, reference being had to the accompanying drawings showing the parts necessary for the understanding of the invention and in which:

Fig. 1 is an elevational view of the not loaded and thus disengaged locking device;

Fig. 2 is an elevational view of the locking device in locking position;

Fig. 3 illustrates the locking device as seen from the right hand side of Fig. 2, and

Fig. 4 is a plan view of Fig. 2 with a central tube shown in section.

The support for the seat 2a is indicated by the upper portion of its central hollow column 1 receiving a rod 2 rigidly connected with the seat 2a. The seat is revolvable and adjustable in height with respect to its support owing to the arrangement of rod 2 in the column 1. The rod 2 is provided with an axially adjustable clamping piece 3 fixed in the desired position by means of a set screw 4 operable by a lever 5a fixed to a nut 5 and having a hole therein to accommodate screw 4 onto which it is threaded. The square-shaped clamping piece 3 carries on two opposite sides a pair of downwardly directed jaws 6 and 7 having each, on their sides facing each other, a cylindrical locking pin 6a and 7a, respectively. The arrangement would of course also work satisfactorily if only one such jaw and locking pin would be provided. A ring 8, having a square cross section, is fixed to the upper end of the column 1 and is provided on its lower surface with a plurality of radially directed stop grooves 8a adapted to cooperate with the mentioned locking pins 6a and 7a. When the said pins 6a and 7a engage a pair of the said stop grooves, for example as shown in Fig. 2 and 3, the seat of the chair is locked against undesired swivelling with respect to its support.

A strong, band-shaped helical spring 9 is arranged about the rod 2 between the ring 8 and the clamping piece 3.

2,764,223 Patented Sept. 25, 1956 Upon a loading of the seat, as it occurs for example when a person sits down on the chair, the seat is forced downwardly against the action of spring 9 so that the locking pins 6a and 7a, which follow the movement of the seat, come out of engagement with the stop grooves 8a of the ring 8 rigidly connected with the column 1 and the seat may be revolved by the user with respect to its support, i. e. the column 1. As soon as the user of the chair stands up the seat is lifted under the action of the spring 9 and the locking pins may again engage a pair of stop grooves of the ring 8. According to the position of the seat at the moment the user stands up a slight revolving movement may be necessary to bring the pins into engagement with the grooves as is easily understandable.

A nut 10 is rigidly connected with the jaw 7 of the clamping piece 3. This nut 10 is adapted to receive a set screw 11, which is not shown in Figs. 1 and 3, and which, when the seat is not loaded, lies in the plane of the ring 8 of the column 1. Screwing of this screw 11 results in its forward end being pressed against the upper portion of the ring 8 so that the seat may be secured against rotation with respect to its support, i. e. to the column 1.

I claim:

1. In a swivel chair, a tubular support, a supporting rod for the seat arranged in said tubular support so as to be revolvable with respect to the latter, a ring of stop grooves fixed to the support, a clamping piece, axially adjustable on said supporting rod and having a downwardly extending jaw, a locking pin provided on said jaw and adapted to cooperate with said stop grooves, and spring means arranged between the clamping piece and the ring for maintaining the locking pin engaged in one of said stop grooves when the seat is not used and permitting disengaging of said pin out of the groove when the seat is loaded.

2. In a swivel chair, a tubular support, a supporting rod for the seat arranged in said tubular support so as to be revolvable with respect to the latter, a ring of stop grooves fixed to the support, a clamping piece, axially adjustable on said supporting rod and having a downwardly extending jaw, a locking pin provided on said jaw and adapted to cooperate with said stop grooves, and spring means arranged between the clamping piece and the ring for maintaining the locking pin engaged in one of said stop grooves when the seat is not used and permitting disengagement of said pin out of the groove when the seat is loaded, and a set screw on said jaw adapted to engage said ring of stop grooves for locking the seat in any angular position with respect to the support.

3. In a swivel chair, a tubular support, a supporting rod for the seat arranged in said tubular support so as to be revolvable with respect to the latter, a ring of stop grooves fixed to the support, a clamping piece axially adjustable on said supporting rod and having a downwardly extending jaw, a locking pin provided on said jaw and adapted to cooperate with stop grooves, a helical spring arranged around said supporting rod for the seat, said spring having its one end bearing against the said ring of stop grooves and its other end engaging the said clamping piece for maintaining the locking pin engaged in one of said stop grooves when the seat is not used, said spring being compressed upon loading of the seat so that said locking pin is disengaged from the stop grooves thereby permitting free revolving of the seat with respect to its support.

References Cited in the file of this patent UNITED STATES PATENTS

Images