Untitled record

No. 30,706.

(PATENTED NOV. 20, 1860.

V. VAN VLEOK.

DENTAL CHAIR.

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UNITED STATES PATENT OFFICE.

V. VAN VLECK, OF NEW YORK, N. Y., ASSIGNOR TO HIMSELF AND RALPH LOCKWOOD, OF NEW YORK, N. Y.

DENTAL CHAIR.

Specification of Letters.Patent No. 30,706, dated November 20, I860.

To all whom it may concern:

Be it known that I, V. Van Vleck, of the city, county, and State of New York, have invented a new and Improved Dental 5 Chair; and I do hereby declare that the following is a full, clear,“and exact description of the same, reference being had to the accompanying drawing, forming a part of this specification.

The drawing represents a vertical central section of this invention.

My invention consists in the arrangement of a longitudinally sliding bolt in combination with the seat of a chair, and with two 15 hemispheres one working inside the other in such a manner that by depressing said bolt the seat of the chair may be retained in any desired position, whether horizontal or inclined; also in the combination with said 20 longitudinally sliding bolt and with the two hemispheres of two toggle arms acting on the head of the bolt and acted upon by a treadle in such a manner, that by depressing the treadle the two hemispheres are 25 locked and the seat retained in its position.

To enable those skilled in the art to make and use my invention, I will proceed . to describe its 'construction and operation with reference to the drawing.

The seat A, of the chair is fastened to the upper surface of the hemisphere B, which is provided with a flange a, by means of screws b. The hemisphere B fits into the top end of the foot or stand C, said top end being 35 hollowed out so as to form a socket D, and in the center of the upper surface of the hemisphere B, a socket E, is formed which receives the hemisphere F. A bolt G, which is firmly secured in the hemisphere F, passes 40 through a conical recess c, in the hemisphere B, and through a central opening in the stand down near to the ground, and the recess c, in the hemisphere B, is of such a size and it is so formed, that said hemisphere 45 is at liberty to move in the socket D, without coming in contact with the bolt G.

By exerting a slight pressure in a downward direction on the bolt G, the two hemispheres are kept down in their respective 50 sockets and the hemisphere B, with the seat can be brought in a horizontal or in an inclined position as may be desired, while the hemisphere F, always retains its horizontal position and serves to keep the hemisphere 55 B, down in its socket. But if a strong pres sure is exerted on the bolt G, the two hemispheres are firmly wedged down into their sockets, and the seat with the hemisphere B, is retained in the position, into which it may have been brought before the pressure on the 60 bolt is applied.

A longitudinal sliding motion is imparted to the bolt G, by means of two pairs of toggle arms H, which are inserted into a cavity d, in the bottom end of the stand or foot 65 C. The top ends of these toggle arms are retained by notches e, in a metal plate /, that is screwed to the top of the cavity d, and the bottom ends of said toggle arms rest in grooves g, on the inner side of the head of 70 the bolt G. The length of the toggle arms H, in relation to the bolt is so adjusted that, if no strain is exerted on the bolt leaving the hemisphere B, with the seat A, free to be brought in any desired position, the centers 75 of said toggle arms are slightly thrown out of straight/lines drawn through their ends as clearly shown in the drawing. By forcing the center of the toggle arms in toward the bolt, their ends are forced apart and a pow- 80 erful pressure in a longitudinal direction is exerted on the bolt G.

The toggle arms H, pass through a slot h, in the treadle I, which works in slots i, j in the lower end of the stand C, being, re- 85 tained in its place by a plate 7c, catching into a groove in the end of the treadle. The backs of the toggle arms are slightly curved and the length of the slot h in the treadle is so adjusted, that the same, when the treadle 90 is raised to the position shown in the drawing, leaves the centers of the toggle arms free to recede from the bolt, so as to exert no pressure on the hemispheres B, and F. But if the treadle is depressed, the ends of 95 the slot h, in sliding down over the backs of the toggle arms, force the centers of the same in toward the, bolt, and the pressure thereby exerted on the bolt causes the hemispheres to be wedged down into their sock- 100 ets thereby retaining the seat A, in the position, into which it may have been brought before the treadle is depressed.

By these means the operator has both his hands free to bring the patient into the .de- 105 sired position and to hold him there until by a pressure of the foot on the treadle the seat is retained in the desired position.

The construction of this chair is very simple and cheap; both hemispheres B and HO

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F, and also the socket D, can be cast and secured in their places without requiring any fitting and the whole device is so easily put together and adjusted, that it can be 5 done with little loss of time.