US1836350A - Surgical outfit - Google Patents

Surgical outfit Download PDF

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US1836350A
US1836350A US113885A US11388526A US1836350A US 1836350 A US1836350 A US 1836350A US 113885 A US113885 A US 113885A US 11388526 A US11388526 A US 11388526A US 1836350 A US1836350 A US 1836350A
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motor
controller
armature
shaft
coil
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US113885A
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Whiteside Howard Austin
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Whiteside Howard Austin
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    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61CDENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C1/00Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design
    • A61C1/0007Control devices or systems
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61CDENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C1/00Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design
    • A61C1/02Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design characterised by the drive of the dental tools
    • A61C1/06Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design characterised by the drive of the dental tools with electric drive
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61CDENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C1/00Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design
    • A61C1/08Machine parts specially adapted for dentistry
    • A61C1/18Flexible shafts; Clutches or the like; Bearings or lubricating arrangements; Drives or transmissions
    • A61C1/185Drives or transmissions

Description

Dec. 15, 1931. H. A. WHITESIDE SURGICAL OUTFIT 5 Sheets-Sheet 1 7 Filed June 5, 1926 VENTO 244mm:

ATIORNQX Dec. 15, 1931. HVA. WHITESIDE 1,836,350

SURGICAL OUTFIT File d June 5. 1926 5 Sheets-Sheet 2 INVENTOR we ,fMwz-s/as.

ATTORNEY 1931- H. A. WHITESIDE 1,836,350

SURGICAL OUTFIT Filed JJne 5, 1926 5 Sheets-Sheet s 75- wmfi i/liim ATTORNEY Dec. 15, 1931. H. A. WHITESIDE SURGICAL OUTFI '1' Filed June 5, 1926 5 Sheets-Sheet 4 INVENTOR ATTORNEY 4 mm wWMi? QNRNN. W N m5 Dec. 15, 1931. H. A. WHITESIDE SURGICAL OUTFIT Filed June 5, 1926 5 Sheets-Sheet 5 ATTORNE -Yi"; l

1 Ella lawn:

Patented Dec. 15, 1931 PATENT;- OFFICE HOWARD AUSTIN WEITESDE, 01' IBVINGTON, NEW YORK SURGICAL OUTFIT Application fled June 5, 1926. Serial No. 118,885.

The present invention relates to a complete surgical outfit and is'more particularly directed toward an electrically operated surgical outfit suitable for operations requiring 5 the cutting or grinding of bone or teeth, and go improvements in certain parts of such out- In bone operations and in dental work, it is common to use power operated tools for cutting and grinding the bone or teeth. Surgical and dental engines in common use for such purposes, however, generally have the motor separately supported and use a flexible drive for the tool. The present invention contemplates an outfit for this purpose in which an electric motor is directly connected to the tool, the motor and tool forming a unit which the operator can handle readily and without danger of shocking the patient or operator. The invention further contemplates electrically connecting such a motorized tool unit with a suitable controller by flexible wiring so that the operator will be able to manipulate the unit without interference and so that the motor speed may be under the control of a controller, operable by the operators foot, or automatically, as desired. The current may be supplied from the power mains, or from a storage battery or dry cells as desired. Outfits contemplated by the present invention are exceedingly light in weight and may be readily operated in any place, even where emergency operations are necessary and from an power source.

Either alternating current, irect current or battery may be used.

An object of the present invention 18 to provide an electrically operated surgical outfit which may be connected to a suitable source of power supply, and which includes a controller interconnected with the motor and power supply, so that the motor may be operated at various speeds in either direction, the speed control preferably being associated with the armature circuit, either in the form I of a potentiometer or a series parallel arrangement of resistances where power is obtained from station mains, or in the form of simple resistance, especially when low voltage battery power is used.

At a particular setting of the resistance, the speed of the motor operated tool is a function of the pressure applied by the operator in grinding oil the tooth structure or bone. Thls is on account of the drawing of an increased current drawn through the resistances which reduces the potential available at the motor terminals. These variations of the motor speed may be considerable and may be compensated for by varying the resistances. The resent invention contemplates the provision of a controller for the armature current by which a higher potential may be applied automatically or manually to the armature terminals to compensate for the drop of the armature speed on account of the load. Where the automatic form of controller is used, the tool speed may be main tained substantially constant. It has been found possible to obtain such automatic control by using an air core or iron core electrodynamometer having a moving coil in series withthe armature, or in shunt with it, for operating the movable contact over a stationary resistance. The connections for the resistance may be in the form of a potentiometer or series. The field of the electrodynamometer may be in series with the motor field where a shunt motor is used, or may be separately excited where a series motor is used. Another object of the invention is to provide an improved controller for electric motors in which the armature current is taken ofl'f a potentiometer having a large part of the resistance in a unit detached from the controller mechanism so as to reduce the heating of the controller proper.

Another object of the invention is to pro- Vide an outfit which will function equally well on alternating and on direct current, and, in carrying this out, substantially noninductive resistances in series with the field and the armature resistor (whether or not potentiometer control is employed) are provided, and the motor windings are made of comparatively few turns so that the power factor of the current in the motor field and.

armature will be greater than it would if the full potential were applied to the motor windings, and so that the power factor of the field tool and having an insulating casing to thoroughly insulate all the electrical parts of the motor from the operators hand aswell as insulation between the armature shaft and the motor driven tool so as to prevent shocking the patient.

A further object-of the invention is to provide a motor for the above purposes having an improved arrangement'of end yoke, bearings, and brush rigging, all of which may be made small enough to be attached to the surgical tool grasped by the fingers of the operator.

vAnother object of the invention is to provide improved dental tools particularly adapted for direct connection to and operation by a motor.

In the subjoined description of the invention, the foregoing objects, and others not specifically mentioned, will be amplified and additional objects and advantages of the inventioncwill be indicated.

The accompanying drawings show, for purposes of illustrating the invention, an embodiment thereof utilizing an automatic foot operated controller, an embodiment using a foot operated controller, together with a showin of the detailed construction of the control ers, the motor, the surgical tools, and modifications of certain of these parts.

In these drawings:

Figure 1 is a circuit diagram for an automatic foot controller having an air core electrodynamometer utilizing potentiometer control in the armature circuit;

Figure 2 is a vertical sectional view, parts being omitted, of the automatic controller shown diagrammatically in Figure 1;

Figure 3 is a sectional" view taken on the broken line 3 of Figure 2, parts being omitted Figure & is a sectional view taken on the line 44 of Figure 2, parts being omitted;

Figure 5 is a fragmentary elevational view taken in the direction of the arrow 5 of F igure 2, parts being omitted;

Figure 5a is a fragmentary view of a detail;

Figure 6 is a sectional view taken on the line 6-6 of Figure 5;

Figures'7 and 8 are plan and side elevational views respectively of an iron core type of electrodynamometer which may" be sub stituted for the air core structure;

Figure 9 is a vertical sectional view through a modified non-automatic form of controller designed more particularly for foot operation; 1

Figure 10 is a sectional view taken on the line 10-10 of Figure 9 and showing the wiring diagram for controlling a shunt motor;

Figure 11 is a fragmentary elevational view taken in the direction of the arrow 11 of Figure 10, and showing'the plug contacts for connecting the controller to the power supply and the motor;

Figure 12 is a view showing the interior of the controller taken in the direction of the arrow 12 of Figure 9, the bottom plate being omitted;

Figure 13 illustrates the contacts and wiring .for controlling a series wound motor, with a structure about like that shown in Figures 9-12 inclusive;

Figure 14 is an elevational view with parts in section, of a form of resistance adapter to be placed in the power supply;

Figure 15 is an elevational view of a motorized tool unit suitable to be held in and insulated from the operators hand while conducting surgical operations;

Figure 16 is a sectional view showing a handpiece detachable by means of a slip joint, and connections between the armature shaft of the motor and the handpiece and too v Figure 17 is a View similar to Figure 16 showing the dental handpiece andv tool with parts in a diiferent position;

Figure 18 is a fragmentary sectional View of a shorter form of driving connection for the handpiece;

Figure 19 is a sectional. view ofa threaded coupling which may be substituted for the slip joint; Figure 20 is an elevational view similar to Figure 15 showing a motorized unit provided with a difi'erent form of handpiece;

Figure 21 is an enlarged detailed view showing this form of detachable surgical handpiece having reversing gear and avariable speed gear drive with the reduction gearing arranged for reducing the speed of the tool below that of the armature speed;

Figure 22 is a fragmentary view of the parts shown in Figure 21 with the gearing shown for a direct drive;

Figure 23 is a sectional view taken on the line 23-23 of Figure 21'showing the mechanism for releasing the drill, mandrel or cutting tool;

Figure 24 is a sectional view taken on the line 24-24012 Figure 21 showing the gear shifting mechanism;

Figure 25 is a fragmentary view illustrating a right angle detachable surgical tool connected with the reduction gear handpiece;

Figures 26 and 26a are sectional views showing the, brush rigging endv of a commutator motor;

'Figure 27 is an end view taken in the direction of the arrow of Figure 26, the end cap and insulating sleeve having been removed from the motor; and

I Figure 28 is a diagrammatic illustration of an induction motor circuit embodying the present invention.

The automatic controller outfit Reference will first be made to the surgical outfit, including arrautomatic controller shown more particularly in Figures 1 to 6, inclusive. This outfit contemplates the use of a. controller which may be set by the operators foot so as to operate the motor at the desired speed'forward or reverse and to associate with this foot control an automatic control which will keep the motor speed substantially constant at the speed at which the controller is set. The detailed construction of a commutator motor is shown in Figures 16, 26, 26a and 27. This motor may be a series motor or a shunt motor. Certain features of the present invention may utilize an induction motor.

In the circuit diagramthe wires 30 and 31 have been designated plus and minus for convenience. A resistance adapter R, to be described in detail, is arranged to be plugged into any suitable outlet so as to take current oil the supply line. This resistance adapter preferably carries three lines designated as 32, 33 and 34 which extend to terminals 35, 36 and 37. This resistance adapter is in practice connected by a flexible cord, preferably carrying three wires, to a controller 38 which may be conveniently located for actuation by the operators foot. In Figure 1, however, the wiring is shown diagrammatically and such cords are omitted.

The current, after passing through the bar 32 of the adapter plug, passes through wiring indicated at 39, part of which is outside the controller and part of which is inside the controller structure, so that the current may be conducted to a ring 40 centrally mounted on an insulating plate 41 suitably carried in the controller housing 42, as shown in Figure 2. This plate has a centrally placed aperture 43 through which passes an operating shaft 44 on the lower end of which is mounted a swinging arm or bar 45 made of insulating material and carrying a number of movable contacts. These figures show a control for a shunt motor. Changes for converting the controller for a series motor i willbe indicated below.

The ring 40 is here shown in the form of a distributing ring and the current passes from it through the field circuit and the armature circuit; The armature circuit, as traced from the ring 40, includes a spring pressed brush 46 carried in the bar 45, a back connection 47 carried by this bar and a second spring pressed brush 48 which is adapted to travel over segments 49 and 50 placed outside the ring 40. These segments are inter- 0 connected by a strap 51 carried on the upper side of the insulating plate 41 and are separated by an insulated spot or segment 52.

The current passes from one or the other of these segments through a wire or lead 53 to asolenoid coil 54 mounted on a soft iron wire core 54'. This core has laminated iron pole pieces or end members 55 and 56 preferably made square, and connected to brackets 57 to facilitate mounting the solenoid on the up.- per side of theplate 41 above an aperture 58 therein. An insulating block or plate 59 is carried on the coil 54 and this block or plate supports a pair of spring contacts 60 and 61 provided with iron armatures 60 and 61' in a position to be held against the end members 55 or 56 when the solenoid coil is energized. The circuit continues from the coil 54 through a lead 62 into the core 54 of the solenoid and the end members and then continues from the contact 60 or 61 which ,is moved against the iron core in a manner to be described, and then through a wire 63 to a terminal marked a in Figure 1. It then passes through suitable leads and terminals in the controller and through a flexible cable into the motor.

For convenience, in Figure 1, these connections are indicated at 65 and the current flows through the same to one side 66 of the armature 67 of the motor.

The current then passes through the armature 67 and returns through a lead 68 to the controller, suitable flexible cord and terminals being provided. Inside the controller the current comes to a junction point 69, where it divides-and part of it passes through the movable coil 70 of an electrodynamometer 7 1. This current passes from the coil 70 through a lead 72 into a metal mounting 73 carried on the end of an arm 74 of insulating material. This mounting 73 carries a pair of knife edged rollers 75 and 76 which are adapted to move back and forth along an arc-shaped resistance coil 77. The wire is anchored to the tapered core by varnish which is scraped off where rollers contact with the wire. The movement of this arm and the rollers is accomplished either through the electrodynamometer 71 or through the movement of the arm 45 in a manner which will be described. A connection 78 is made between the point 69 and the roller mounting as indicated. This connection may be a permanent or a variable resistance 79 to permit adjusting the sensitivity of the electrodynamometer, where it is desired to have a dynamometer coil in parallel with another resistance, or it may be omitted where it is desired to have the dynamometer coil in series with the armature. It is indicated in the drawings, however, in the form of a variable resistance such as might be used in adjusting the device.

The current passes from the rollers 75 and 76 into the coil 77 and from the coil 77 another spring pressed brush 101in'to one or through a lead 80 to a back contact 81 carried on the armature of a relay 82. It then passes from the back contact 81 through a spring 83 to the iron pole piece 84 which car- 5 ries a solenoid coil 85 for a purpose to be pointed out below. The current passes from the frame of the coil through leads 86 and 87 to a terminal in the controller and thence through the suitable flexible leads to the point 37, indicating the terminal of the resistance adapter coil 34 to a junction point 88 where it connects with the negative side of the line.

In the, drawings, potentiometer control of the armature circuit is indicated, a connection 89 being made between the points a and b so that the resistance coils 77 and 34 are in series and so that the potential for the motor armature is tapped oil the coil 77. The connection 89 may be omitted where it is desired to have straight series resistance control of the armature circuit.

Returning now to the center ring 40, the circuit will be traced through the field side of the motor. Short. segments 90 and 91 are carried on the underside of the insulating plate 41 adjacent the ring 40 and opposite segments 49 and 50. Another pair of segments 92 and 93 are placed outside the segments 90 and 91. The segments in each pair areseparated by an insulated space or seg ment, as indicaied'at 94 and 95. A longer continuous segment 96 is placed outside the segments 92 and 93. The segments 91 and92 are connected bya strap97 on the upper side of the plate 41, while the segments 90 and 93 are similarly connected by a strap 98.

The current may pass from the ring 40 through a spring pressed brush 99 carried by the arm through a back connection 100 and the other of segments 90 or 91, provided the arm 45 has been swung out of the neutral position. The current then passes through plates 90 and through suitable wiring and and by terminals carried by the controller, the flexible cable, all of which are designated by the character 102, to the motor field 103. Returning from the motor field through similar connections 102 to the other'segments 92, the current passes through brushes 103 back connection 104 and brush 105 (all of which are carried by the arm 45) into the 5 fixed segment 96. The field current then continues through the connection indicated at 106 to the fixed coil 107 of the electrodyna mometer 71. It then passes from the fixed coil through wiring 108, part of which is inside the controller and part of which is in the flexible connections, to point 36 forming a terminal of the resistance adapter. It then passes through the resistance 33, which is preferably non-inductive or of very low inductance, into the negative side of the line.

Certain of the constructional details'of the electrodynamometer form of controller are indicated in these figures and will now be described. The insulating plate 41 is suitably fastened against a shoulder 110 on the inside of the inverted drum-shaped metal housing 42. Between the top of the plate and the top 111 of the housing are carried such electrical connections as may be conveniently housed therein, also the spring for returning the parts to neutral when the foot is taken away from the controller. -Thearm 45 carrying the movable brushes 46, 48, 99, 101, 103, and 105 may be moved back and forth by a foot operated arm indicated at 112. When this arm is in the neutral position the brushes 48, 99 and 101 rest on the insulated areas 52, 94, and 95 respectively, and the circuits for the armature, potentiometer, and field are broken in these points. This will de-energize the coil 54 and the spring contacts 60 and 61 will be separated from the pole pieces 55 and 56 of the solenoid 54. One or the other of these springcontacts 60 or 61 is adapted to be moved up to engage the corresponding end member of the solenoid when the arm 45 is moved out of neutral position.

As here shown, the mechanism for moving the above contacts 60 and 61 includes a pair of cams 113 and 114 which are pivoted at 115 and 116 on the upper side of the arm 45 and carried directly underneath the spring contacts 60 and 61 respectively These cams have a sloping surface indicated at 117 and 118 engageable with the arma'tures 60 and 61 so that the movementof the arm 45 will cause the cam to engage the contact member andbring it against the adjacent end mem- 4 the corresponding contact against the endof the solenoid until the arm has moved far enough to cause the brushes and jumpers to interconnect the stationary contacts and energize the motor circuits. This will complete the circuit through the solenoid 54vand armature, energizing the solenoid so that the contact will be held in the upper position to maintain the circuit closed until it is opened by the return of the arm to the neutral position, or otherwise. l

The power supply or motor circuit may be opened however, for various other reasons, and in order to permit the arm 45 to be brought back to the neutral position, even though the magnet coil 54 is de-energized, the cams are so arranged that they can pivot about the points 115 or 116 to permit the camto pass by the lowered contact 60 or 61. This contact will engage the side'of the corresponding cam member and press it inwardly against the scissors-likespring 120. This spring holds these cam members against stops 121 and 122 so that they remain underwhen these contacts are to be raised by the cam members. According to the present construction it is necessary to return the arm 45 to neutral before again starting the motor. During this return movement one or the other of these contact members will 'engage the outside of the corresponding cam member and press it inwardly to permit the, arm to return to neutral. 1

The arm 45, as here shown, carries two pins 123 and 124 which project downwardly referred to.

and which are adapted to engage the sides of segment-carrying arms 125 and 126, respectively. These arms have teeth 127 which are in mesh. A late 128,.preferably of insulatin materia, is attached to and sup ported%) the ,under side of the insulating plate 41 y means of a number of posts 129, or in any other suitable manner. This plate carries a pivot post 130 on \which is'pivotally mounted the segment arm 125 as well as the dynamometer which is carried on the underside of the plate 128. The movable parts of the dynamometer are carried on a shaft which supports the other segment arm 126 in a manner to be described.

As here shown the stationary coil 107 of the dynamometer has a supporting frame 131 which is mounted on insulating posts 132 and 133 attached to the lower side "of the plate 128. The movable coil 70 of the dynamometer is mounted. in a frame 134 which is mounted on trunnions 135 and 136.

: These frames are preferably made of a high resistance aluminum alloy to reduce eddy currents. The upper trunnion passes through, and is mounted in, the insulating plate 128 while the lower trunnion is pivote ally mounted in, and passes through, a strap 137 which extends across the lower ends of the posts 132 and 133. The upper end of the shaft or trunnion 135 is attached to and supports the segment arm 126, a s uare hole 138 in the segment arm may be tted onto the squared end of the shaft 135. The insulating arm 74, above referred to, is secured to the lower trunnion 136, and a spiral coiled spring 139 is supported from the plate 137 and is attached to the arm 74 so as to tend to move it in a counter clockwise direction, as indicated in Figures 1 and 4.

During the movement of the arm one or the other of the pins 123 and 124 will be held against the corresponding segment arm 125 or 126 causing one of these armsto move with the controller arm 45, the other one swinging in the opposite direction, thereby moving the trunnion 135 and parts attached to it. This will carry the ovable coil of the electrotlynamometer and t e arm 74 along start the motor up at the desired speed, or can change the motor speed at will. The arrangement of segments and pins permits the same operation forward or reverse. The resistance 77 is wound on an insulating core 140 supported by a depending member 141 attached to the under side of the insulating plate 128 in a roper position to permit the knife-edged rollers 75 and 76 to engage the wire in the coil. The under side of the late 128 also carries the solenoid coil 85 a ve The insulating core 140 for the rheostat coil 77 carries a contact member 142 against which the rollers will be brought when the dynamometer moves the same to the extreme position, which is beyond the position to which the foot lever can move these parts. This will bring the contact 142 into the circuit, and will cause the armature current to flow from the coil 77 through the contact 142 through a lead 143 into the coil 85 andthence into the wire 87 leading to the negative side of the circuit. This will energize the coil 85 and its soft iron laminated core and will cause the armature to be attracted from the back contact 81 thereby opening the motor armature and potentiometer circuits. This will stop the motor and will cause the dynamometer to return from the high point. It will also de-energize coil 54 and release the spring contact or 61., It will then be necessary for the operator to start a sin by returning the operating arm 112 an parts carried thereby to the neutral position which is readily permitted by the cams 113 and 114 as above described. To again start up the motor, the arm ismoved' as before, mechanically closing the contact 60 or 61.

Where the motor is to be used on power mains such as volt house lightin mains, the motor field 103 is preferably designed to use but a very small part of the-line potential, the most of the potential drop being consumed in the fixed dynamometer coil 107 and the resistance 33 carried in the resistance adapter. In this manner the power factor f of the motor field circuit may be kept rela-- tively high where alternating current is used. Where the outfit is designed for power or lighting mains, the armature may be designed to stand the full 110 volts and to opcrate on part of this potential, tapping it ofi the potentiometer resistor. The selected voltages could be applied by the controller. When the motor has been started at the lower voltage, the electrodynamometer control, which will function according to the current drawn through the armature, will with increase in the load, cause the'arm to shift to with it over resistance 77. It will thus be apply greater potential to the armature terseen that the operator can move the controller to first close the circuit in either forminals so as to hold the speed more nearly constant with increased oadr The roller ward or reverse direction and then move contacts will move back and forth according the dynamometer armalong the resistanceto to the load. When, however, the motor is overloaded, which might happen should the grinding tool become caught in the teeth, or

.too great pressure be applied, the armature will stop, and the counter E. M. F. will disappear so that a heavy current would be momentarily drawn throu h the electrod namometer coil. This vvil move the rollers over against the limit contact 142 thereby energizing the coil 85, opening the motor armature circuit, and causing the coil 54 to release its armature contact 60 or 61 permanently opening the motor circuit.

I The resistance 34 in series with the motor armature circuit may be comparatively small or may be omitted, as desired. The control- 'ler above described operates entirely satisfactorily in controlling a shunt motor when operated by alternating or direct current. The resistances and inductances as 'well as the dimensions of the motorimay be so proportioned by calculation that the armature current will be approximately in phase with the field current so as to develop torque on alternating current; By a single change of connections to be indicated later, and changes in the resistances the controller may be adapted for" a series motor having the properly proportioned windings. Where the motor is to operate on low voltage storage batteries, the resistances 34 and 35 are omitted and straight resistance control employed, as the potentiometer would wear down the battery.

In order to eliminate sparking at the contacts, condensers 144 and 145 are connected across the field and armature terminals respectively. These condensers would in practice be placed inside the controller housing.

In Figures7 and 8, illustrating an electrodynamometer having an iron core which may be substituted for the air core dynamometer plate 128 in any desired manner. Straps 155 preferably made of brass,

of Figure 1, the stationary field coils are indicated at 150 and 151 and the movable coil at 152. These coils will be connected in the circuit in the same way as coils 107 and respectively. L The fixed coils 150 and 151 are wound in substantially the same manner as the field coils for a two pole motor and are mountedinside a field structure 153 comstampings having consequent poles 154. These stampings are fastened together in any suitable manner to provide a laminated structure and may be mounted underneath the and 156 are fastened to the top and bottom of the field structure 153' and 157 also made of laminated iron. Shaft 158 passes through this core and the upper end of it is adapted to be connected into the segment arm 126in the same manner as trunnion 135. The lower end of the shaft carriesthe arm 74 in the same manner as the trunnion these straps,-. support the core The foot operated controller, which in many particulars is like the automatic controller heretofore described, is shown in detail in Figures 9 to 12 inclusive. This controller is adapted to be placed on the floor convenient for the operator to actuate it by the foot and flexible connections are provided by plugging it to the power supply (which may include a resistance adapter if desired) and to a motorized tool unit.

The resistance adapter shown at R, and

in Figure 14, has two terminals 160 and 161 by which it may be plugged into a convenient outlet. The adapter has a through connection 162 and two resistance coils 163 and 164 preferably of low inductance.

These connections and coils lead to three unsymmetrically located contacts 165, 166, and 167 for a plug receptacle (not shown) on a three conductor cord indicated at 168, which may be plugged into the resistance adapter.

his cord isprovided-with a three contact plug by which it may be plugged into the controller as indicated at 169. (Figure 11.) The three contacts on the controllerindicated at the left of Figure 11 are so arranged that the connections can not be improperly made. it will, of course,- be understood that the resistance adapter maybe omitted and the desired resistances disposed in any other convenient fashion.

For convenience, the through connection 162 in the controller is termed positive. The connecting wire in the 3 conductor cord leads to a terminal 169' in the controller rece tacle and is there'connected to a terminal 1 0 inside the controller and a strap 171 carried on a. fixed insulating plate 172 conducts the current to a centrally placed ring173. An insulating arm 174 similar to the arm 45 is carried underneath the plate 172 and has contacts adapted to sweep over the lower face of this insulating plate.

As indicated in dotted lines, in Figure 10, and in full lines in Figures 9 and 12, the plate 172 carries segments 175 and 176 ad- ]acent the central contact 173. These segments are separated by an insulated area 177 and are back connected by a strap 178.-

ried on the bar 174 to one or the other of the segments 175 or 176, provided the arm has been moved out of neutral position. The

current then passes through the lead 187 to.

"through a brush 195 back contact 196, and

brush 197, allof which are carried by the bar 174, into one or the other of the pairs of buttons 180 to 183', inclusive. The buttons 180 to 183 inclusive, are connected by taps 198 to a resistance coil indicated at 199 and mounted inside the controller. The current passes through this resistance coil to a button 200, then by lead 201 to the terminal 202 carried by'the controller. The current then returns through the three conductor flexible cord previously referred to, to the contact 167 and then through the resistance 164 to the opposite side of the line.

As shown in the drawings, a connection 203 is made from the strap 178 to the end of the resistance coil 199. This connection places the resistance coil 199 in circuit at all times when the controller arm is moved out of neutral position, and permits potentiometer control of the armature current. The omission of thislead 203 makes the device a straight series resistance control. The

disposition of these resistances and their dimensions and characteristics may be the same as previously described or referred to and for the same purposes.

The field side of the motor connections asvhere shown aresubstantially the same same as is shown at the left of Figures 1 and- 6. The current may be traced from the inner segment 204'through the lead 211 to a terminal 212 on the controller, thence through a wire 213 in the four-conductor cord to the motor field 214 and returning from the inotor field through a conductor 215 to the other field terminal 216 on the controller; thence to the wire 217 in the controller to the segment 206 and through the jumper contacts. on the arms 174 to the segment 208; thence from terminal 218 through the wiring in the controller to the .fiel d connection terminal 219 of the controller and throughthe thiee conductor flexiblecord to the resistance coil 163 as indicated. To reduce sparking small condensers 144 and 145 are connected in the controller.

The insulating plate 172 is carried in a housing 220, and a foot operated arm 221 is pivotally mounted on the top of this casing and operably connected to a shaft 222 which extends down into the casing through the plate 172 and carries the swinging arm 174 ina position to sweep the brushes across the contacts carried by the plate 172. The resistance coil 199 may be conveniently mounted above the plate 17 2 and space is also provided for a spring 223 which cooperates with pins 224 and 225 carried by the casing and by an arm 226 attached to the shaft, respectively, so that the spring will return the foot lever to the neutralposition when pressure is removed from it. The same sort of sprin return would be used in the controller 0% Figure 2, it being omitted therein to simplify the drawings.

While the description above given relates to circuits for, and the control of a shunt wound motor, it is really possible to control a series wound motor by substantially the same controller and to supply substantially .the same surgical outfits with series motor.

Figure 13 indicates the connections for the series motor. In a foot operated controller,

the parts are arranged similar to those shown in Figures 9 and 12 inclusive. The coil characteristics and resistances will, of course, he designed according to the motor being controlled. Instead of using a central ring 174 one may now employ a split ring having segments 174' and 17 and may dispense with the outer segment 179 on the armature side. The jumper 230 is designed to reach from the ring 174" to the buttons 180, etc., so as to connect the series resistance 231 into the circuit. The current then passes from the segment 174" to the armature 232 of the motor to the outer segment 208', corresponding with segment 208, and through the field side of the motor and field side of the controller in the same 'fashion as heretofore described, returning from the segment 174 through a connection 233 to the other terminal of the controller which ma be connected to the line through a series resistance 234 if desired. If it is desired to use potentiometer control of a series motor,.connection 235 is made from the resistance 231 across to the controller terminal.

It will, of course, be understood that in all these outfits the proportioning of and disposition of the various resistances will be dependent upon the characteristics of the motor, the voltage of the power supply, and

other variables. The accurate determination of'these variables is essential to secure satisfactory operation. I

F igure- 28 diagrammatically illustrates a surgical outfit employing single .phase alternating current. Here the power supply is under the control of a switch 240 which.

may be conveniently made up in the form of a foot operated switch. Thecurrent is carried to the motorized tool unit by a flexible cord indicated at 241. Here the motorized tool unit will include-an induction motor 242, a hand piece 243, and tool indicated at 244. This hand piece is preferably provided with a reversing gear and speed reduction gear an example of which is shown in detail in Figures 20 to 24, inclusive.

While the outfits above described utilize either potentiometer or series resistance control for the commutator type motor, and reverse the motor by reversing the connections of the field relative to the armature connections, it will of course. be understood that the commutator motor may be reversed by other means such as shifting the brush rigging, and that the speed of the tool may becon- Y trolled by a variable speed hand piece. Also alternating current motor.

that a reversing hand piece may be used with orwithout variable speed control the same as above indicated with respect to the The motor Y 26, 26a, and 27 An insulating casing 250 is preferably used to form the outside of the motor, as well as to support the field structure and the bearings for the armature shaft. As shown in Figure 16, the end of the motor to which the hand piece above referred to, is attached, is provided with a permanently closed end wall 251 having ventilation o enings 252 if desired, and carrying a meta bushing 253 preferably made of light metal. This bushing is permanently secured inthe end of the motor housing in any suitable manner, as for 'ex-' ample, by a screw 253'. The exposed end of the bushing 253 is preferably threaded as "indicated at 254 to receive a coupling or slip joint used in the hand piece. Acase hardened steel bearing member 255 is carried inside the bushing 253 so asto provide a wearresistant bearing having minimum friction.

The left end of the armature shaft 256 may be kerfed as indicated at 257 and is insulatively mounted'in a bearing member 258 by an insulating sleeve 259 and an insulating washer 260. This bearing member 258 is drilled in from the right, as indicated, to provide a recess to receive the washer and insulating sleeve, and the washer and tube previously treated with suitable varnish are ing dogs 261 to cooperate with the hand piece. It is preferably recessed at 262 in the exposed end for a purpose to be described, a closed wall 262 being provided to prevent oil 'from' passing from the hand piece into the insulating coupling.

The insulating casing 250 forms a rigid self ,supporting housing for the motor, is an integral part of the motor and directly supports the armature shaft bearings and the field structure indicated at 263. The field structure preferably is made out of very thin laminations of silicon steel, and a field winding of few turns is preferred, so as t9 improve the power factor of the field circuit. In making up the motor the inside of the casing is accurately turned to size and the field structure and windings forced into place and held there by suitable varnish thereby accurately centering the same.

As shown in Figures 26 and 27,a metal ring 264 is passed in to the open end 265 of the motor housing and may be held in place by a number of screws 266. This ring 264 is provided with a yoke 267 which supports the brush rigging and the adjacent end 268 of the armature shaft. As here shown this end of the shaft is carried in a case hardened, steel bushing 255' carried in the tubular end 270 of the yoke 267. A screw 271 is threaded into the end 270 of the yoke and a spring pressed plunger 272 is utilizedto urge the shaft to the left and to hold the shoulder on the bearing 258 against the hearing at the other end of the motor.

The armature 273 and commutator 274 are spring 279 preferably made of steel music wire. These springs each have free ends 280 which are adapted to ride in a groove 281 in the commutator. the springs thereby acting as brushes. The opposite ends of the springs are anchored in holes in the insulating disc 27 5. The posts 277 and 278 extend through the insulating disc and are provided with terminals 282and 283. Similar terminals 284 and. 285 are carried by the .insulating disc, all the terminals projecting toward the right as indicated in full lines in Figures 26 and 27. 283 provide connections for thearmature leads, while the terminals 284 and 285 provide connections for the field leads, the field connection in the motor being soldered to these terminals.

The terminals 282 and slipped onto the motor so as to surround the brush rigging and yoke and to be supported on the yoke. An insulating cap 287 is provided with four receptacle contacts, two of which are indicated at 288 and 289. These receptacle contacts are placed so that they may be connected with the field and armature terminals 282, 283, 284 and 285. By placing these terminals unsymmetrically, it is obvi ous that the cap 287 can not be connected so as to confuse the armature and field connections. This insulating cap preferably carries the flexible cord indicated at 290 in Figures 15 and 20, which cord carries the four wires leadingto the controller. In order to secure the cap 287 in lace without imposing any strain upon the rush rigging, an insulating coupling member 291 is provided with a threaded metal sleeve 292 adapted to cooperate with threads on the outside of tubular end 268 of the yoke. This coupling member 291 has a shoulder indicated at 293 to engage the cap 287 and hold it in place in an obvious manner. This coupling member may also be provided with a swiveled eye 294' to facilitate hanging the motorized unit on a suitable hook when not in use.

As the motor contemplated by the present invention is preferably a reversible one, it is necessary to accurately adjust the brush rigging so as to place the brushes in the neutral zone for good commutation. This may be accomplished by adjusting the disc 275 and contacts and brushes carried by it as a unit until proper commutation is obtained. The

, parts are drilled and pins 276 are then inserted in place and it is impossible to get the brushes out of adjustment. The yoke 267 is constructed so as to be open at the' sides so as to permit observation of the motor and to reduce the weight.

A modified form of motor is shown in Figure 26a. Here the end 294 of the motor casing 295 extends over as far as the right-end of the insulating ring 286 of Figure 26. An insulating disk 296 having a tubular flange 297 is attached to the end of the motor casing by screws 298. The disk 296 carries a light metal tubular bearing holder 299 corresponding with the tubular end 270 of the yoke 267, these parts being clamped together by lock nut'275 and screw 275". This disk 296 carries the brush rigging in the same manner as the disk 275, the parts being given the same reference characters. It also carries the case hardened bearing and cap thrust bearing and supporting eye as in Figure 26.

In assembling this form of motor, the armature commutator, and disk 296 are assembled and the brushes placed on the commutator. The brushes are adjusted to the neutral position before the screws 298 are placed.

It is possible to construct a motor as above described and make it sufiiciently small to be attached directly to the hand piece of a surgical tool. For example a motor suitable for dental work may be 1 in diameter by 2 long over all and weigh less than three ounces. Carefully proportioning the parts and accurate assembly permits the motor to operate The ham? pieces Figures 15 to 25, inclusive, show various forms of hand pieces more particularly designed for use in the motorized tool units. They may, however, be used with any sort 'of surgical engine. The type of hand piece shown in Figures 15 to 19, inclusive, will first be described. A'few of the details of the slip joint of this hand piece are shown more clearly in Figures 20 and 21.

As above described, the exposed end of the metal bushing 253 is threaded at 254 for the reception of a coupling or slip joint for carrying the hand piece, and the exposed end of the bearing member 258 (connected to the armature shaft) is provided with a pair of dogs 261 for driving the rotatable parts of the hand piece.

As shown in Figure 16, a slip joint is provided. As here shown it has an inner slip joint sleeve 300 threaded at 301 to cooperate with the threads on the end of the bushing 253. It is open at the outer end 302 so that the shaft of the tool can be passed into it. The sleeve 300 is provided with a spring catch member 303 having a conveniently placed thumb piece or actuating member 304 on which the operator may press the thumb to release the catch from the other sleeve in the slip joint. This catch member 303 may be attached to the sleeve 300 by screws 305, as indicated.

The shaft 306 of the hand tool is threaded as indicated at 307 and a dog carrying clutch member 308 is threaded thereon. This dog carrying clutch member has dogs 309 to cooperate with dogs 261 carried on the end of the motorshaft, and is threaded against a tapered shoulder 310 on the shaft 316 so as to bind the parts tightly together. A split pin 311 is attached to the dog carrying member 308 by a transverse pin 312, these parts being swiveled together to prevent binding. This split pin is adapted to extend between the pairs of dogs as indicated and to pass into the recess 262 in the end of the bearing member 258. This split pin fits the walls of the recess closely and tends to prevent overrunning of the hand piece shaft and motor shaft so as to make the apparatus run more quietly and with less jarring.

The shaft 306 is provided with a collar 313. This collar runs between shoulders 314 and 315 carried on members 316 and 317 respectively, these members being threaded together as indicated at 318 so as to hold the collar between them. The member 317 constitutes the outer slip joint sleeve and extends towards the motor, passing outside the tubular slip joint member 300. It is notched as indicated at 319 (shown the more clearly in Figure 21) to receive the base 320 of the slipjoint catch member, and is also cut away at 321 so that the catch 303 on the slip joint may engage and hold the parts in place. In order to insulate the slip joint and this part of the hand piece, one may, if desired, attach an insulating ring 322 to the slip joint piece .which threads onto the motor and another insulating ring 323 to the ring 317 which is coupled to this member. This insulation may be used or omitted as desired.

The left end 324 of the hand tool shaft 306 is rotatably carried in the long bearing 316 in the member 316. This member 316 is recessed as indicated at 325 to receive and house one end 326 of the two-part slidable outer sheath S used in coupling and uncoupling the tool to the hand piece. The inside of this recess 325 is provided with a keyway 327' to receive a key 328 carried inside the sheath member 326 so that the sheath is normally non-rotatable relative to the motor housing. The other part 329 of the sheath, preferably knurled as indicated so that it can be easily grasped by the operator, is threaded at 330 to the part 326. It extends to the end of the hand piece and houses the clutch to be described. An inner sheath 331 is rotatably carried inside the outer sheath member 329 and is clamped in place.

A loose washer 332 is placed outside the shaft 324 and between the adjacent ends 333 and 334 of the inner sheath 331 and the outer sheath part 326 respectively. A slight clearance is provided between these parts so that they do not bind. A pin 335 couples the left or outer end of the shaft 324 with the adjacent end 336 of a clutch operating member 337 slidably mounted in and non-rotatably carried by the inner sheath 331 thereby providing a driving connection and a swiveled joint so that the parts carried in the inner sheath may be driven from the shaft 324. The inner sheath 331 is slotted on the upper side as indicated at 338 to guide a projection 339 on the member 337. A clutch operating bell crank lever 340 is pivoted at 341 in the inner sheath 331 and is provided with a long inclined arm 342 which passes through a slot 343 in the member 337'. This slot has an inclined upper wall indicated at 344 which may be serrated to engage with the bell crank arm 342. The heel-345 of the bell crank is adapted to press a sleeve 346 which is slidably carried in the inner sheath 331 to cause an inclined surface 347 thereon to engage against the inclined end of a tubular springclutch member 348. The other end of this clutch member 348 and the adjacent end of the inner sheath 331 are inclined as indicated at 349 so as to permit clamping a tool shank in place.

Figure 16 shows the parts in the position from. the motor, it is merely necessary to.

grasp the motor in the hand and press the thumb against the thumb-piece 304 and separate the slip joint sleeves. When one desires to insert a tool, the parts are moved from the position of Figure 17 to the position of Figure 16. To accomplish this movement, the operator grasps the knurled surface on the outer sheath and presses toward the motor.- The parts move slightly to take up the clearances and then the shoulder 313 on the hand tool spindle 316 is brought against the shoulder 315 on the slip joint sleeve 317. Then the sheath and clutch parts may be moved to the right,-the key 328 sliding along the keyway in an obvious manner. To fasten the tool in place, it is merely necessary to pass the shank of the tool in through the outer end of the sheath and into the clutch 348 and then pull outwardly on the sheath. During this clutching operation the key 328 travels in the keyway 327 and the outer sheath 331, clutch parts and bell crank lever move to the left causing the arm 343 of the bell crank to travel along the inclined sur- 324 and all the parts which need to be lubricated are efi'ectively concealed, and that the insertion and removal of the tool does not uncover any lubricated surface. There will,

therefore be no occasion for soiling the operators hand by the escape of lubricant from the hand piece. It will further be noted that itis impossible in practice for the hand piece to come apart and permit the motor driven parts to accidentally slide out of the sheath. This is on account of the threading of the two parts 326 and 329 of the sheath together and the locking of the parts thereby. In hand pieces of somewhat similar construction heretofore available the outer sheath has been attached to the non-rotatable parts by a set screw which occasionally loosens and permits all the motor driven parts to drop out of the outer sheath especially where a small drill happens to be fastened into the hand piece. The dropping of these power driven parts is likely to cause injury.

Figure 18 shows a short form of connection which may be substituted for certain parts of the construction shown in Figure 16. Here the does 309, corresponding with the dogs 309 of Figure 16, are out directly on the shaft 306 adjacent the shoulder 314, corresponding with the shoulder. 314. The split pin 311 is attached in place by the transverse pin 312 as before, and the similar member 316 can be used as in Figure 16. This short form of connection, particularly suitable for persons with small hands, may be used with a short form of coupling, shown in Figure 19 in the form of a metal tube 350. threaded as shown at 351 to cooperate with the threads 318 on the hand piece and threads 254 on the metal bushing. Thiscoupling member may of course be made the length of the slip joint and substituted for it, if desired. It may also be covered with insulation as indicated at 352.

Figures 20 to 24, inclusive, show a different form of hand piece suitable for use in a motorized tool unit of the nature heretofore referred to. This form of hand piece has a variable speed reduction gear and may or may not be provided with a reverse gear drive as desired.

The hand piece is provided with a. shaft 360 having driving dogs 361' cooperable with the dogs on the end of the motor shaft as before, this shaft being rotatably carried in a coupling member 362 which may be coupled to the slip joint member in the same manner as themember 316 shown in Figure 16. The end of the shaft carrying" member 362 is threaded as indicated at 363 and a second coupling member 364 is threaded onto it as indicated. Th s coupling member 364 is adapted to house the reversing gear which will now be described.

The reversing gear is driven from the end of the shaft 360, which is provided with a gear 365. The shaft is drilled as indicated at 366 to receive a short shaft 367 slidably mounted therein and keyed to it. as indicated by thekey 368. The shaft 367 is provided with dogs 369 which engage with corresponding dogs 370 carried'on the end of a shaft 371. The shaft 371 also carries a gear 372. An idler gear 373 is suitably mounted on the end of the first coupling member 362 and is in mesh with the gear 365 on the end of the driving shaft. A counter shaft 374 is carried in the coupling member 364 and is provided with gears 375 and 376 which may be in the position indicated or which may be moved to the right so as to mesh the gear 375 with the gear 372 and the gear 376- with the idler gear 373. This movement is accomplished by a finger piece 377 which projects out through the side of the hand piece and which is carried on the shaft 374. This finger piece has an arm 378 which engages in a groove in the shaft 367 so as to slide it back and forth inside the shaft 366 in the driving shaft 360.

When the parts are in the position indicated in the drawing, there is a direct drive from the shaft 366 through the slidable shaft 367, dogs 369, 370 to the shaft 371. When the slidable gear is moved to the right, the

dogs are disconnected and the idler and reversing'gear are brought into play so that the shaft 371 will run in the opposite direction.

The shaft 371 is mounted in the second coupling member 364 and in the plug 379 carried inside a third coupling member 380. The plug 379 and second coupling member 364 may be made integral, if desired. The third coupling member 380 houses the reduction gear and carries the tool holder.

As here shown, the left end of the shaft 371 is provided with a gear 381 and with driving dogs 382. A hollowshaft 383 is mounted in the endof the coupling members 380 and this hollow shaft is slidably mounted on an inner shaft 384 to which it is pinned by a pin 385 extending into a slot 386. The hollow shaft 383 is provided with dogs 387 adapted to cooperate with the dogs 382 on the shaft 371 for direct drive, and the shaft 384 carries a hollow member 388 pinned to it by a pin 389. This hollow member has gear teeth 390. The gear 381 on the driving shaft 371 is in mesh with a gear 391 carried on a shaft 392 suitably mounted in the coupling member 380. This shaft also carries a gear 393 which is adapted to be in mesh with the gear 390 when the parts are in the position shown in Figure 21. These pairs of gears are proportioned so as to reduce the speed of the shaft 392 to about half of the speed of the shaft 371. The shaft 392 is moved by a finger piece 394 similar to the finger piece 37 7. This finger piece has an arm similar to the arm 37 8 so as to engage with and slide with the hollow shaft 383 to disengage the dogs 387 from the dogs 382. Springs 395 and 396 are reduction gears 393 and 390. A nose piece 400 is attached to the coupling member 398 by screws 401. One of these screws acts as the pivot for a tool locking and releasing dog 402 shown more clearly in Figure 23. This locking dog has a projection 403 adapted to extend down into a groove 404 in a tool shank 405. The end of this tool shankis cut away at one side as indicated at 406 to fit in a non-circular hole in member 388. The releasing dog 402 has a slight extension 408 which the operator may engage with the fin ger so as to swing it far enough to release the tool. The motion of this dog 402 is limited by a slot 4:09 through which one of the screws 401 passes. A projection 410 on the dog is adapted to enter a recess in the coupling member 398 to hold the dog in its inner pos1- tion.

The hand piece shown in Figures 20 to 24, inclusive, may be made with or without the reversing gear or with or without the re'-. duction gear. It is suitable #for being attached to the motor by the slip jgint or con- %likrlig in the manner heretofore indicated.

en this form of hand piece is used, one may use a non-reversible motor or may operate the motor at constant speed. This form of hand'piece is more particularly designed for use with an alternating current induction motor which preferably operates at one speed and which is inconvenient to reverse.

Where a tool hand piece of the type used in Figures 21 to 24, inclusive, is to have a right angle tool, the connections may be those shown in Figure 25 in which the threaded joint between the coupling members 380 and 388 is indicated in section. Astandard right angle end is substituted for the straight end.

What is claimed is:

- 1. In combination, an electric motor having field and armature windings, a controller adapted to be connected to a power source, a

pair of field leads and a pair of armature leads interconnecting the controller and 1110- tor, said controller including a resistance coil,

I an electrodynamometer having a movable coil whose current is proportional to the current in the armature circuit, and a movable contact carried by the movable coil for cooperating with the resistance to vary the voltage v 7 applied to the armature according to the load.

2. In combination, an electric motor having field and armature WindingS a controller adapted to-be connected to a powertsource, a pair of field leads and a pair of armature leads interconnectingrthe controller andmotor, said controller including a resistance coil which is connected across the line when the controller is actuated to start the motor, an electrodynamometer having a movable coil whose current is proportional to the current in the armature circuit, and a movable contact carried by the movable coil for cooperating with the resistance to vary the voltage tapped ofi the coil and applied to the armature according-to the load.

3. In combination, an electric motor having field and armature windings, a controller adapted to be connected to a power source, a pair of field leads and a pair of armature leads interconnecting the controller and mo tor, said controller including a movable circuit controlling arm, a solenoid having an armature contact adapted to be closed when the arm is moved from its neutral position, a resistance coil in series with the solenoid coil, an electrodynamometer having a movable coil whose current is proportional to the current in the armature circuit, and a movable contact carried by the movable coil for cooperating withthe resistance to vary the voltage applied to the armature according to the load.

4. In combination, an electric motor'having field and armature windings, a controller adapted to be connected to a power source, a pair of field leads and a pair of armature leads interconnecting the controller and motor, said controller including amovable c1rcuit controlling arm, a solenoid havlng an armature contact adapted to be closed when the arm is moved from its neutral positlon, a resistance coil which is connected in series with the solenoid and across the line when the controller is actuated to start the motor, an electrodynamometer having a movable 0011 whose current is proportional to the current in the armature circuit, and a movable contact carried by the movable coil for cooperating with the resistance to vary the voltage applied to the armature according to the load.

5. In combination, an electrlc motor having field and armature windings, a controller adapted to be connected to a power source, a pair of field leads and a pair of armature leads interconnecting the controller and motor, said controller. including a resistance coll, an electrodynamometer having a movable coil whose current is proportional to the current in the armature circuit, a movable contact carried by the movable 0011 for cooperating with the'resistance to vary the voltage field leads and motor armature leads for controlling the speed and direction of rotation of the motor, certain of said movable contacts being carried by an arm, a solenoid coil the motor circuit.

having a normally open armature contact which is closed when the arm is moved out of neutral position to establish a circuit through the solenoid coil, and an electrodynamometer having a movable coil whose current is proportional to the current in the armature circuit, there bein a movable contact carried by the movable coll for cooperating with the resistance in the motor circuit to vary the HOWARD AUSTIN WHITESIDE.

US113885A 1926-06-05 1926-06-05 Surgical outfit Expired - Lifetime US1836350A (en)

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Application Number Priority Date Filing Date Title
US113885A US1836350A (en) 1926-06-05 1926-06-05 Surgical outfit
US58092031 US1960470A (en) 1926-06-05 1931-12-14 Brush rigging and end cap assembly for surgical motors and the like

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1207548B (en) * 1961-07-15 1965-12-23 Werner Hartmann Surgery Hand Motor
US3229369A (en) * 1962-03-02 1966-01-18 Kaltenbach & Voigt Dental handpieces
US3353272A (en) * 1963-09-18 1967-11-21 Micro Mega A Joint Stock Compa Dental hand pieces
DE1266444B (en) * 1964-05-27 1968-04-18 Austenal Europa Inc Zweigniede Hand motor for driving surgical tools
US3530586A (en) * 1964-02-27 1970-09-29 Sybron Corp Speed reducer construction for driving dental tools

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1207548B (en) * 1961-07-15 1965-12-23 Werner Hartmann Surgery Hand Motor
US3229369A (en) * 1962-03-02 1966-01-18 Kaltenbach & Voigt Dental handpieces
US3353272A (en) * 1963-09-18 1967-11-21 Micro Mega A Joint Stock Compa Dental hand pieces
US3530586A (en) * 1964-02-27 1970-09-29 Sybron Corp Speed reducer construction for driving dental tools
DE1266444B (en) * 1964-05-27 1968-04-18 Austenal Europa Inc Zweigniede Hand motor for driving surgical tools

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