No. 659,2l6. Patented Oct. 9, I900; C. B. BOWLING 8|. W. D. DURHAM.
DENTAL CHAIR.
 (Application filed Jan. 9 IQ'OO.) (N0 MOdOI.) 2 Shear-Sheet I.
wil
witwemo M z 6 aawaw No. 659,216. Patented out. 9, I900. c. B. uowum; &.w. n. DURHAM.
DENTAL CHAIR.
 (Application filed Jan. 9. 1900.: (I10 Model.) 2 Sheets-Sheet 2.
UNITED STATES PATENT OFFICE.
CHARLES E. DOWLING AND WILLIAM D. DURHAM, OF SWANSEA, SOUTH CAROLINA.
DENTAL CHAIR.
SIEGIFIGATION forming part of Letters Patent No. 659,216, dated October 9, 190i).
Application filed January 9, 1900. Serial N6. 851. (No model.)
To all whom it may concern:
 Be it knownthat we, CHARLES B. DOW LING and WILLIAM D. DURHAM, citizens of the United States, residing at Swansea, in the county of Lexington and State of South Carolina, have invented certain new and useful Improvements in Dental Chairs; and we do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.
 This invention relates to improvements in folding-chairs, and has particular reference to that class known as dental chairs.
 The object of this invention is to provide a dental chair that can be easily and readily moved from place to place and set up in proper position for use with little or no expense or trouble.
 The invention consists, essentially, of a chair-seat, an adjustable back therefor, a suitable frame adapted to raise the chair at different heights, and an adjustable means for locking said chair in any desired position upon the frame.
dicates a rack held together by suitable rungs.
and provided in the upper side of its rails with notches (1,. k
 B are strips or supports pivotally secured at one end of the rack A and having their opposite ends pivotally secured to a chair-seat O by means of a hollow shaft D.
E E are supports or braces pivotally secured to the under side of the seat 0 of the chair and upon the hollow shaft D and have their lower free ends secured together by suit= able rungs E, having its ends e projecting out beyond the sides of the supports E, as shown. These projections or ends care adapted to removably fit in the notches aof the rack A.
v To the under side of the chair-seat O, pivoted upon the hollow shaft D, is a suitable leg and foot support F, which is removably pivoted on the shaft D beneath the seat and connected to the under side of the said seat at its forward edge by suitable adjustable connecting means F, having a suitable spring F for holding said connecting means in po- 'sition and is provided at its lower end with a foot-rest f;
Gr G are segmental racks secured to the .sides of the chair-seat and have their curved portion depending downwardly adjacent to the supports B B, as shown, and are provided at suitable intervals with holes or openings 9 g for a purpose hereinafter stated.
 H H are suitable spring-arms secured to the supports B B and are provided about midway thereon, to the inside thereof, with I suitable pins 71 h, adapted to fit into the openings g g in the racks G G for the purpose of The invention further consists in the novel holding said racks in locked position. To the upper end of the spring-arm H is secured a rod I, which passes through the hollow shaft D beneath the chair-seat and is attached to the angle-lever K, which is pivoted to the. top of the spring-arm H and is for the purpose of causing said arms H and H to simultaneously approach their respective racks and lock the same or to be simultaneously thrown away from said racks, as desired.
 L is the back of the chair, hinged to said chair in any suitable manner, and is provided with stay or brace rods L L, having suitable notches Z, as shown, and pivoted to the back of said chair. The notches Z l are adapted to fit on suitable pins Z, secured at or near the front side of the chair-seat, and are for the purpose of holding said back at any desired angles to the seat of the chair, as is evident. The chair-back L is provided with a suitable head-rest, supported upon an adjustable bar M, adapted to be raised or lowered and to be held at any desired position thereon by means of a set-screw N or any other suitable means.
 In the back L are suit able slots L L through which set and are adjustably secured bolts L L which secure the hinges L L for the purpose of permitting the raising or lowering of the back of said chair, as desired. These bolts are adjustable, whereby they may be set and secured in any parts of the slots L L as is evident. v
 Having thus described our invention, What we claim, and desire to secure by Letters Patent, is
 1. In a dental chair of the character described, a suitable support,a hollow tube journaled in said support, a chair-seat pivoted on said tube, and segmental racks secured to said seat; with arms secured to said support and provided with suitable means for engaging said racks, and suitable means extending through said hollow tube and connecting said arms, whereby said arms are operated to simultaneously move inward to engage said segmental racks, and to be simultaneously disengaged therefrom, as set forth.
 2. In a dental chair of the character described, a suitable support,ahollow tube j on rnaled therein, a seat provided with an adj ustable back pivoted on said hollow tube, and segmental racks secured to said seat; with spring-arms secured to said support and provided with suitable means for engaging said racks, and suitable means extending through said hollow tube connecting said spring-arms,
whereby said arms are simultaneously operated to move inward to engage said racks, and moved away to be disengaged therefrom, as set forth.
 3. In a dental chair, the combination of a suitable support, a hollow tube journaled therein, a seat pivotally mounted thereon, and segmental racks secured to the sides of the seat, with spring-arms secured on said support and adapted to each engage one of said racks, a lever pivoted to one of said springarms, a movable rod in said hollow tube, said rod being secured at one end to the lever, and having its opposite end secured to the opposite spring-arm, whereby said arms are operated to move inward to engage said segmental racks, and to be simultaneously disengaged therefrom, as set forth.
 4E. The combination with a suitable base, having journaled therein a hollow tube, of a chair-seat rockably mounted on said tube, a rod passing through said tube and provided at each end with spring locking-arms, a rack adapted to be engaged by said arms, and means for operating said arms and rod to lock the seat at any desired angle, as set forth.
 In testimony whereof we aifix our signatures in presence of two witnesses.
CHARLES E. DOWLING. WVILLIAM D. DURHAM.
Witnesses:
D. O. HERBERT, A. S. HYDRIOK, Jr.