Electric-dental-instrument holder.

Application filed November' 3,1904. Serial No. 231,307.

To a,ll, whom it may concernBe it known that I, Monroe N. Callender, a citizen of the United States, residing at San Francisco, in the county of San Francisco and 5 Stateof California, have invented certain new and useful Improvements in Electric-DentalInstrument Holders, of which the following is a specification.

This invention relates to improvements in :o electric dental-instrument holders, the object of the invention being to provide an apparatus for supporting in a manner convenient to the operator dental instruments which utilize an electric current.

:5 In present forms of switchboards for electric dental instruments in which the instruments are supported upon the board the cords for each instrument must be of sufficient length to allow complete freedom of movement^of 10 the instrument when being used by the operator, and these cords hang down when the instrument is in position upon the switchboard, and therefore are inconvenient and present an untidy appearance.

It is the object of my invention to provide a switchboard and holder which shall be free from this objection.

In the accompanying drawings, Figure 1 is a front elevation of the apparatus. Fig. 2 is a 0 section thereof on the line 2 2 of Fig. 1, one of the drums being shown in section. Fig. 3 is a broken vertical section of the apparatus on the line 3 3 of Fig. 2.

Referring to the drawings, 1 represents a 5 cabinet within which the apparatus is inclosed.

This cabinet may form the upper portion of a larger cabinet containing drawers and the like, the remainder of which, however, is omitted from the drawings as immaterial to the pres0 ent invention. Upon the front wall or supporting-board 2 of the cabinet are mounted any desired number of spring-clips 3, each adapted to hold a dental instrument. In the present instance only two of such spring-clips 5 are shown; but as many more may be supported thereon as desired. The dental instruments shown in the present instance are an electric lamp 4 and a hot-air injector 5. In each case the current is supplied to the dental instrument by means of wires 6, which pass 50 through an opening 7 in the front wall of the cabinet and are coiled around a drum 8, the ends.of the wires then being connected to two binding-posts 9, extending inwardly from the flanged end 10 of the drum, said binding-post 55 being connected through said end with concentric collector-rings 11 on the end, which revolve in contact with spring-contacts 12 13, supported upon one of the posts 14 which support the shaft 15 of the drum. 60

When the operator takes down a dental instrument and moves the same from the switchboard, thereby drawing the cords through the aperture 7 and causing the drum to revolve, he thereby winds up a spring 16, secured to the 65 drum and to the shaft 15, upon which it revolves, and upon releasing the cord the spring 16 rewinds the same upon the drum, withdrawing it through the aperture 7, so that when the dental instrument is replaced in its proper 70 spring-clip upon the switchboard the cord is withdrawn behind the switchboard and wound up out of sight. There is provided with each drum the pawl-latching device commonly used on window-shades— that is to say,upon the end 7 5 of the drum are pivotally mounted a pair of pawls 17, one or the other of which is adapted to engageanotch 18,formed in the periphery of a circular support 19 for the pawls secured to the post 14. When the operator draws out the 80 cords, unwinding the same from the drum, he will allow one of these pawls to fall into the notches, so that the drum is held stationary while the instrument is being used, and after use the operator will slightly pull the 85 cords to withdraw the pawl out of the notch, and thereby allow the spring to wind up the drum. The two spring-contacts are connected to the source of electricity, one contact, 12, directly with a wire 20 and the other contact, 90 · 13, through the members of the spring-clip by a wire 21, leading to one of said members, and by a wire 22, leading from the other member to a source of electricity. Thus when the dental instrument is withdrawn from the 95 spring-clip the circuit is closed through said

780,322 spring-clip; but when the instrument is inserted into the elip the circuit is broken and no current is being used.