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Publication numberUS550685 A
Publication typeGrant
Publication dateDec 3, 1895
Filing dateOct 4, 1894
Publication numberUS 550685 A, US 550685A, US-A-550685, US550685 A, US550685A
InventorsCharles W. Mujstz
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
US 550685 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

4 2 Sheets-Sheet 1. C. W. MUNZ.

(No Model.)


Patented Deo. s, 1895..


{No Model.) 2 Sheets-Sheet 2. G. W. MUNZ. PIANO STOOL.-

No. 550,685. Patented Deo. 3, 1895.





SPECIFICATION forming part of Letters Patent No. 550,685, dated December 3, 1895. Application iiled October 4,1894. Serial No. 524,895. (No model.)

To all whom, it may concern Be it known that I, CHARLES NV. MUNZ, a citizen of the United States, residing at Hillsdale, in the county of Hillsdale and State of Michigan, have invented certain new and useful Improvements in Piano Stools, of which the following is a specification, reference being had therein tothe accompanying drawings.

The invention consists in the peculiar construction of a ratchet device for raising and lowering the seat, in the means for supporting -and holding1 that ratchet device in the seat-standard formed to turn, in the peculiar construction of the ratchet operating spindle, and in the construction of an adjustable back carried by the stool-seat, all as more fully hereinafter described.

In the drawings, Figure l is a vertical longitudinal section through the piano-stool embodying my invention. Fig. 2 is a detached perspective view of the rack-standard and the pawl-lever. Fig. 3 is a cross-section on line 0: Fig. l. Fig. 4L is a section through the push-pin of the paWl-lever, showing the parts separate and illustrating the manner of connecting the pin with apawl. Fig. 5 is a side elevation of the seat, illustrating the adjustable back. Fig. 6 is a central section through the bracket. Fig. 7 is a detached perspective view of the parts of the back-supporting arm and the actuating-lever.

A is the usual wooden standard supported upon the legs B.

C is the seat, cushioned, if desired, and provided with the depending tubular post D, adapted to enter an aperture in the standard A. This post D, Ipreferably make of metal, provided with a lianged upper end, by means of which it may be secured on the under side of the seat.

In the lower end of the socket in the standard A is a pivot-block made in two interlocking sections a b and having an interior bearing c, adapted to receive the cone-shaped point F ofthe rack-bar G. The plates a l) have overlapping lianges d engaging over the top `of the conical head F to prevent its withdrawal from the stool, the pivot-block being secured in position by means of the bolt or pin H, passing through the standard.

The rack G is substantially semicylindrical in cross-section, as shown in Fig. 2, and its inner face on each side is provided with the teeth M. These teeth are separated sufficiently to form between them a space for the movement of the spring N, which at its upper end is connected to the upper end of the rack G, and is connected at its lower end to the lower end of the pawl-lever C. This pawl-lever is provided at its lower end with a substantially triangular-shaped iange or foot P, adapted to engage in the interdental spaces between the teeth M to lock the stool in its adjusted position vertically, and the lever is pivoted on the pivot-point M in the post D. The lever is provided centrally with the enlargement or lugs Q, which are adapted to bear against the edges of the rack G, as shown in Fig. 3, to act as a guide therefor.

c are lugs or shoulders at the top of the rack-bar, adapted to engage upon the top of the lugs Q in the uppermost position of the parts to prevent the withdrawal of the post.

h is a lateral pin having an eye at its inner end engaging over the upper end of the pawl-lever O. This pin at its opposite end is provided with an oifset or bend i, adapted to pass through an aperture j in the pushpin 7c, which is guided in sliding bearings on the under side of the seat C. Between the aperture j and the inner end of the pushpin 7a is a groove m, in which the pin 7L is adapted to lie and is secured by means of the covering-block Z, glued or otherwise secured thereon.

ois a spring sleeved over the pin h between a shoulder on the stool and the' end of the pin 7c and acts, with its tension, to normally hold the iiange P into engagement with the notches in the rack-bar. lt will be evident from this construction that the stool may be turned in the usual manner, but that the rotation thereof will not effect its height, the stool turning upon the conical head F in the bearing c of the pivot-block.

To raise or lower the stool, the operator pushes on the pin k, which will rock the lever O on its pivot to release the iiange P from the rack bar. The spring N is of sufficient tension to substantially balance the weight of the seat and its connecting parts, so that in raising the seat practically no effort is required.


On such a seat as this I prefer to apply an adjustable back, as is shown in Figs. 5 to 7, inclusive, in which 1 is a bracket having depending ears 2, in the lower end of which is supported the ends of the shaft 3, centrally upon which is journaled one end of the bifurcated lever 4, which terminates in the upwardly-curved head 5. On one side of this head is a groove 6, engaging over a camflange 7 on the block S, secured to the shaft 9, which is journaled near the top of the bracket and has a handle or knob 10 at the outer end beyond the side of the seat.

The seat-back 11 is supported at the upper end of the standard or post 12. At the lower end the standard has a vertical slot, in which is the set-screw 13, which lat its inner end en ters one arm of the bell-crank lever 14, which at its elbow is pivoted on the pin 15, supportzwith a hollow base and a seat, of a tubular extension on the seat, a pawl carried by the ed in the outer ends of the bifurcations of the lever 4. The other arm of this lever extends inwardly and has a segmental slot 16, engag ing over the shaft 3, anda hooked extension 1S is a spring secured limiting the vertical adjustment of the pawl 1 and seat, comprising lugs on the upper end of the rack and oppositely extending lugs on the pawl at or near the pivot thereof below the plane of the rack lugs, substantially as described.

17'beyond that shaft. at one end to the top of the bracket and bent into a graceful curve downwardly and rearwardly, engaging at its opposite end the notched extension 17 of the bell-crank lever.

The position of the seat-back may be adj usted by turning the rod or shaft 9, which will rock the lever 4 upon its pivot and carry j i ard, a rack bar pivotally secured in an aperture therein, a seat, a tube depending from the up or down the pin 15, which supports the back, throwing it forward or back, as shown in Fig. 5.

The sitter resting his back against the seatback moves it and rocks the bell-crank lever against the tension of the spring. The movement of the back is limited by the slot 16 of the shaft 3.

Vhile I have shown the spring N in connection with my device, I do not wish to be 3 ing seat, of a bracket secured to the rear edge limited to its use, it being evident that the stool may be operated without it.

IVhat I claim as my invention is 1. In a piano stool, the combination with a tubular standard and a seat, of a tubular extension on the seat slidingly engaging in the standard, a rack bar in the standard and disconnected from the tubular extension having an enlarged inverted conical shaped shouldered head at its lower end, a removable pivot in presence of two witnesses.

block located in the base of the standard consisting of two independent sections having overlapping portions at their upper ends enl gaging over the shoulder on the head of the rack, a removable securing pin in the standard located above the pivot block, a pawl member pivotally supported in the tubular extension, and interlocking means on the pawl and rack for limiting the upward movement of the seat, substantially as described.

2. In a piano stool, the combination with a tubular standard and seat, of a tubular extenf sion on the seat working in the standard, a rack bar pivotally supported on the standard having a channeled side, with oppositely disposed teeth at its lower end, a pawl pivoted in the tubular extension, and formed with a tooth on its lower endJ means for moving the Y pawl, and a spring located in the channel of the rack having its upper end secured to the upper end thereof and its lower end secured to the tooth on the pawl and adapted to work between said teeth, substantially as described.

3. In an adjustable stool the combination extension, a rack carried by the base, means for moving the pawl to engage the rack at different points, and means on the rack for 4. In a stool, the combination of the standseat and embracing the rack bar, a pawl lever pivoted in the tube, the spring connected to the top of the rack bar and the bottom of 1 the pawl lever, the lugs Q on the pawl lever, and lugs c on the rack bar acting as stops to 1 limit the movement of the tube, substan- 5 tially as described.

5. In a stool, the combination of the revolvthereof, a lever journaled in the lower part of the bracket, a seat back standard supf ported on a pivot at the end of the lever, a lever or arm extending inward from the seat end of the arm, and a cam controlling the movement of the first named lever, substann g tially as described.

In testimony whereof I affix my signature CHARLES W. MUNZ. 4 IVitnesses M. B. ODOGHERTY, L. J. WHITTEMORE.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5393125 *May 28, 1993Feb 28, 1995Steelcase Inc.Height adjustable chair arm assembly
US5439267 *May 28, 1993Aug 8, 1995Steelcase Inc.Chair with adjustable arm assemblies