US428664A - Adjustable chair or stool - Google Patents

Description

J. BRIGGS. ADJUSTABLE'GHAIR 0R STOOL.

(No Model.)

910. 428,664 Patented May 27, 1890.

' UNITED STATES PATENT OFFICE.

JOSHUA BRIGGS, OF BOSTON, MASSACHUSETTS.

ADJUSTABLE CHAIR OR STOOL.

SPECIFICATION forming part of Letters Patent No. 428,664, dated May 27, 1890.

Application filed November 25, 1889. Serial No. 331,438- (No model.)

To all whom it may concern:

Be it known that I, JOSHUA BRIGGS, of Boston, county of Suffolk, State of Massachusetts, have invented an Improvement in Adjustable Chairs or Stools, of which the following description, in connection with the accompanyin g drawings, is a specification, like letters and numerals on the drawings representing like parts.

This invention has for the object the production of an improved adjustable chair or stool, more especially adapted as a musicstool.

In my invention the seat has at each end rigid brackets, the said brackets being each provided with a carriage adapted to slide upon an inclined track secured to the main body of the chair, and to hold the seat in adjusted position I have combined therewith a paWl-and-ratchet mechanism constituting a locking device, the pawls being under the control of a rock-shaft exposed at one or both sides of the chair.

Figure l of the drawings in front elevation represents an adjustable chair embodying my invention; Fig. 2, a longitudinal section thereof in the line at, Fig. 3 being a partial section in the line 93', and Fig. 4 is a side View partially broken out.

The chair-frame is composed, essentially, of bifurcated side pieces A, connected by suitable rounds A A the branches of the side pieces being represented as stiffened by a brace B. Each side piece at its inner side, as herein represented, has attached to it a track a, the cross-sectional shape of which is represented in Fig. 3, and below each track is a rack or ratchet plate I), attached by screws 1), the said rack-plate having a series of notches to be engaged by the pawls c, of which there are two, the said pawls being attached to a rook-shaft 0, supported in suitable bearings in the brackets or arms cl at each side of the seat 01', which latter is and may be suitably upholstered.

The rock-shaft has a suitable handle, as (1 by which to turn it to cause the pawls to be disengaged from the notches of the rack-plates whenever it is desired to lower or to raise the seat, the pawls being kept in engagement with the said notches by means of a spring, as 6, shown as attached to the under side of tracks, so as to slide thereon, as best shown in Figs. 2 and 3.

In the chair herein described the seat is always in horizontal position; but it slides up and down upon inclined tracks.

The brackets 01 are connected together at opposite sides of the seat by means of a rung g. r

The round or cross-piece A at the top of the side pieces constitutes a back for the chair, and near this round or cross-piece I have pivoted an auxiliary back D, it being composed'of a wooden bar, the ends of which are inserted into and secured in sockets or openings formed in two metal arms D, pivoted to the side pieces at D the said pivots being herein supposed to be studscrews. This auxiliary back may be either used in the full-line position to make an extension upwardly of the back of the chair, or may be turned down into its dotted-line position to close the space between the cross-piece A and the seat, the arms D in their downturned position resting against suitable stops h.

Viewing Fig. 4, it will be seen that the edge of the bracket 01 next the frame-A is recessed or chambered to receive a spiral spring m, which at its lower end is attached to a stud 10 of the brackets and at its upper end to a suitable stud 011 the frame, there being such a spring on each bracket. These springs counterbalance the weight of the seat, so that it maybe moved up and down with great ease, and may be used to advantage with any form of locking device or adjusting means for the seat.

I claim- 1. A chair composed, essentially, of the side pieces having inclined tracks a, rack-plates located below and projecting beyond said tracks, and a vertically-adj ustable seat having brackets rigidly secured thereto and provided With inclined faces to rest on the side pieces, to thereby always maintain the seat horizontal, carriages secured to the inner side of said brackets to embrace the projecting edges of the tracks, and a rock-shaft having its bearings in said brackets, and pawls eonneeted to said rock-shaft to normally engage said rack-plates, substantially as described.

2. The combination, with the side pieces, the rack-plates connected to the inner sides of the side pieces, the horizontal seat having rigidly-attached brackets, a rock-shaft extended through said bracket-s having pawls attached thereto, and an arm 6', a spring to normally actuate the roek-shaft,and handles (Z upon the projecting ends of the rock-shaft to turn the same, and thereby remove the v pawls from the rack-plates without tilting the seat, of carriages secured to the inner sides of the brackets and adapted to engage with and slide on the said brackets, substantially as described.

JOSHUA BRIGGS.

WVitnesses'.

Geo. W. GREGORY, E. J BENNETT.

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