US1384975A - Dental-engine hand-tool - Google Patents

Description

W G SHELTON.

DENTAL ENGINE HAND TOOL.

APPLICATION HLED OCT. 6, I917.

Paten ted July 19, 1921.

' WITNESSES s mw n r w A y B WILLIAM GENTRY SHELTON, OF NEW YORK, N; Y: I

nnnrnn nnerun HAND-TOOL.

Specification of Letters Patent.

Patented July-1 9, 1921,

Application filed October 6, 1917. Serial No. 195,028.

To all 1/) 7mm it wm z concern:

Be it known that I, WILLIAM Gr. SHEL- TON, a citizen of the United States of America, residing in the borough of Manhattan, city, county, and State of New York, have invented certain new and useful Improvements in Dental-Engine Hand-Tools, of which the following is a specification.

The object of this invention is to provide in a hand tool a self-contained dental engine and hand piece wherein the-motor is at all times under the control'ofthe operator by a simple movement of the position of the hand, irrespective oftheposition of the fingers of the hand holding the hand piece. By control ofthe motor in the presentinstance is particularly meant the starting, stopping and reversing of the motor, as oocasion' may demand. The illustrated form: of the invention shows the motorswitch controlled by a. slight rotary movement of the hand piece upon its axis and upon the axis of rotation of the tool mounted therein when the tool is mounted in the prolongation of the axis of the hand piece. The various structural details of the invention" are developed in their proper order in the description;

In the drawings accompanying this 1pplication, one practicable embodiment oft e invention is illustrated, inwhich drawings,

Figure l, is a top view partly in horizontal section, of one form of my improved device.

Fig. 2, is a vertical section taken on a plan at about the line .2 2, ofFig. 1,. the crosssectional line ofFig, 1, being illustrated in this view by the line 1-1.

Fig. 3, is an elevationof the device shown in Figs. 1 and 2, but 011 a smaller scale. In this view, the outer casing is shown broken away, for the purpose of showing theswitch, and

Fig. 4, is a detailed view of the wiring which is found convenient inthis device;

In these drawings, Fig. 8', showsthe device full size and'Figs. 1 and 2, are'on a scale of two to one approximately.

l V hen the hand piece 5 of the instrument is grasped by the fingers of the operator in the usual manner of holding a dental hand piece, the motor casingG is dependent therefrom at the sideof' the hand. This present invention, particularly relates to the control ofthe motive power by means of a rotary movement of the hand piece relative to the motor casing, this" being rendered possible by the manner of connection be tween these two parts. The hand piece'is shown provided with an outer shell, orsleeve 7-, which is mounted tubular bracket 8, fast to-the upper portion of the motor casing. The tool carrying spindle 9, is located at-thebackend, within this tubular bracket 8. Of course, it is to be assumed that it is provided at itsforward end with a suiiicient or proper tool holding chuck. The bracket 8-; isshown-having a screw threaded platelO, at the back end, having a screw threaded connection with the upper portion of the motor casing, this plate constituting a closure for the gear housing 11. The sleeve 7, is held in its-loin gitudinal'position by a ring 12, engaging a flange on the sleevean'd drawing this up againsta screw threaded nut l3, mountedon an exterior screw thread on thebracket 8.

The spindle 9, is shown disposed trans versely ofthe motor shaft 14:, and the driving connection between these is preferably a reduction transmission, there-being a worm 15- onthe armatureshaft 14 and a worm wheel 16, fast upon this spindle 9, the gears being mounted in the-housing portion 11. According to the present showing, this is a ten to one reduction.

The motor illustrated issupposed to have a shunt wound field, havingat the lower side, or the side opposite the transmission mechanism a commutator- 17, which coacts with-brushes, one of'which is illustrated at 18, mounted parallel with the" axis of the rotation of the armature and engaging the rear face to the commutator; A reversing switch is illustrated at 19, which-switch is shown carried by a" reciprocatory bar 20, which is disposed substantially parallelwith the axis of rotation of the armature Compression springs 21, 22, are shown mounted upon the bar 20 and locatedbetween heads 23 and 24 on the bar and the wall of the motor casing. These springs normallyhold the switch in the neutral, Orcircuitopen position.

The switch illustrated is actuated upon the rotation of sleeve'l', relative to the motor casing by means of an arm 25 fast with such sleeve. In the presentillustration the arm-is shown provided with an integral collar 25 embracing and secured to the sleeve; This arm is articulated to the outer, or upperend of the bar 20. The arm 25 is shown for rotation upon a provided with a pin 26, transversing a slot 27 formed upon the motor casing.

The motor is preferably wound for operation from an ordinary electric light fixture and is provided with an opening 28 at the lower end for the entrance of the wires, which are indicated in the circuit diagram 4, by reference characters 29-30. One of the wires 29, is shown lead to a binding )ost 31, the other wire 30, being lead directly to one of the fingers, or switch blades 32, the other blade 33 being connected by a wireEA to thebinding post 81. The tern1inals35-36 of the field 37 are shown connected to this binding post 31. The switch illustrated comprises a block 38 of insulating material, provided on each edge with three notches and upon respective side with diagonally disposed plates 39 to. Plate 39 having a contact in Fig. 4; at the upper left hand portion of the block and at the lower right hand portion and connected by means of a wire l1, with the brush 18. The plate 10 has a contact at the upper right hand portion and at the upper left hand portion and is connected by a wire 42, with brush 18. In. Fig. at, the switch block is in the extreme opposite position of that shown in Fig. 2,, and the position intermediate to these two, brings the fingers 82-33 in the intermediate notches, and out of contact with either of the plates, which is the normal, or off circuit position and the idle position of the engine, and which position is automatically assumed by the parts, due to theaction' of the springs 21-22, when the operator releaseshishold upon the sleeve 7.

The motor shaft 14: is shown provided at its opposite ends with spherical bearing surfaces 140-141. At the upper end 14:0 is shown engaging a properly prepared bearing face on the screw. cap 1 12 and that of the lower end 1&1 engaging a properly formed socket in the end of an adjustable bearing, shown in the form of a set screw 1423, held in position by means of a lock set screw 14:45

It is to be noted that the motor portion ofthe device is normally dependent from the dental hand piece and that the center of gravity of the motor portion is well below the portion of such hand piece gripped by the fingers of the operator, and that there is a rotary motion of the sleeve 7 relative to the tool spindle 9 within it and relative to the motor casing 6, and the arma ture shaft 14. Of course, it is to be understood that if the operator wishes the entire structure to have a rigid feel in his hand, he will move the sleeve 7 and with it the actuating arm 25 to the limit of their movement, namely, until the pin 26 engages the end of its guide slot 27. As a matter of fact, in mostcases, the parts will be so proportioned that upon the switch fingers 32-33, coming in the end notches of the switch block 19, the 'pin 26 will be at the limit of its movement and positively stop in such position.

The operation of the device is substantially as follows:

The operator takes hold of the sleeve 7 of the dental hand piece in the usual, or customary manner of holding the same, and permits the motor casing 6 to depend therefrom at the back, or side of his hand. When he wishes to establish the current, he rocks his hand, or rotates the sleeve 7, as the case may be, in'the predetermined direction for moving the switch 19, by means of the arm 25, to establish the current for rotating the motor in its forward, or normal direction. When he desires to stop the operation of the tool he may do so without removing it from the point of application, by a slight reverse rotation of the sleeve 7 which will then bring the switch fingers 3233 into the intermediate position. Sometimes in dental operations, it becomes desirable to quickly reverse the tool, as for instance, when a drill gets stuck, or when some portion of the apparatus becomes entangled, as for instance with the rubber dam, in which case, the operator rotates the hand piece in the reverse direction to its full extent, causing such rotation to take place about the axis of the tool spindle 9, the switch then passes through the open circuit, or off current position before passing to the reverse position.

7 It is to be understood that changes in detail of construction may be made within the scope of the claims, as occasion requires, without departing from the spirit of my invention. 7

What I claim is:

1. In a device of the character described, the combination of a dental handpiece adapted to carry a tool, a motor, said handpiece and motor being formed as a portable unit, and means controlling the operation of said motor comprising a finger-actuated sleeve rotatable around said dental handpiece.

2. In a device of the character described, the combination of a dental hand-piece, adapted to carry a tool, a motor, said handpiece and motor being formed as a portable unit, means controlling the operation of said motor comprising a finger-actuated sleeve rotatable around said dental hand-piece, and stops limiting the turning movement of said sleeve.

3. In a device of the character described, the combination of a dental hand-piece, adapted to carry a tool, a motor, said handpiece and motor being formed as a portable unit, and means controlling the operation of said motor comprising a finger-actuated sleeve rotatable around said dental handpiece, said motor having its center 01": gravity below the axis of said hand-piece.

4. In a device of the character described, the combination of a dental hand-piece, adapted to carry a tool, a motor, said handpiece and motor being formed as a portable unit, and means controlling said motor comprising a finger-actuated sleeve rotatable around said dental handpiece, said controlling means having three operative positions, two running and a stop position, and means normally tending to bring said controlling means to its stop position.

5. In a dental engine hand tool, the combination with a dental hand piece, of a motor casing dependent from the rear end of the hand piece, a motor contained in such the operation of casing, a switch for starting, stopping and reversing the motor, the hand piece being 20 provided with a finger gripping portion having independent rotary movement, and an operative connection between such finger gripping portion and the said switch.

In a device of the character specified 25 the combination with a tool spindle and a finger grip surrounding the same, a motor casing dependent from the rear end of the spindle and having its center of gravity well below the axis of said spindle, a switch for lVILLIAM GENTRY SHELTON.

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