US3388472A - Dental drill control - Google Patents

Description

June 18, 1968 N. P. BAKER 3,388,472

, DENTAL DRILL CONTROL Filed Oct. 1, 1965 s Sheets-Shet 1 AIR 8 TURBINE CONTROL BOX DIAPHRAGM SWITCH BOX AIR INTAKE TO DIAPHRAGM FIG. .2

INVENTOR NATHAN P. BAKER June 18, 1968 N. P. BAKER DENTAL DRILL CONTROL 3 Sheets-Sheet Filed Oct. 1, 1965 m 00m mm N0 INVENIOR NATHAN P. BAKER ISTORNEY June 18, 1968 N. P. BAKER DENTAL DRILL CONTROL 5 Sheets-Sheet 5 Filed Oct.

ATTORNEY United States Patent 3,388,472 DENTAL DRILL CONTROL Nathan Price Baker, 1311A Quarrier St., Charleston, W. Va. 25301 Filed Oct. 1, 1965, Ser. No. 492,082 13 Claims. (CI. 32-23) ABSTRACT OF THE DISCLOSURE A control for a turbine type dental drill is provided in which the operator by means of a mouth held controller connected to a diaphragm switch which through relays and solenoid valves selectively controls the supply of air and water to the drill. Parallel foot actuated controls are also provided for conventional operation of the drill.

tist position his finger around or on the drill handpiece,

which position is constantly changing with respect to the tooth he is working on. During such operation there are many positions that the handpiece will be in while working on various teeth in a patients mouth which will make it almost impossible for the dentist .to maintain a steady controlled pressure of such dental control and have a feeling of the grinding operation on a patients teeth. Also with only one switch on the conventional dental handpiece, the dentist has no selection between drilling with air or air and water. In other words, the dentist may only turn the drill on and oif.

If the dentist uses a foot control means for controlling the above operations of the above high speed type of turbine dental engine and drill handpiece, the dentist is handicapped in his movements about a patient, standing one leg and partially on the control foot which actuates a movable foot switch or the like on the fioor during the movement of the dentist when grinding the various positioned teeth in a patients confined mouth.

The instant new dental control means solves the above problems by providing a mouth and air control and diaphragm means in combination with an accompanying circuit, ratchet relay means and solenoid valve means for selective operation of a high speed air driven dentist drill handpiece accompanied with selective actuation of an air stream, or combined streams of air and water as directed by the dentist on a patients tooth during drilling thereof.

More specifically, this new dental control embodies a diaphragm actuated control or switch means which is responsive to a sucking or vacuum like impulse through the dentist control mouth piece and conduit connected to the diaphragm chamber which actuates the diaphragm and ratchet relay operated control switch to turn on the drill with air and water discharging at the tip of the drill and tooth being worked on. A blowing impulse by the dentist through the mouth tube imparts a difierent movement to the diaphragm which through the various aforementioned control system actuates the drill with only air discharging on the tip of the drill. It is to be understood, however, that the diaphragm switch may be also connected to the control circuit so that a sucking impulse on the mouth piece will only turn on air and the 3,388,472 Patented June 18, 1968 turbine of the handpiece while a blowing impulse on the mouth piece may selectively turn on air and water and the turbine within the purview of this invention.

It is to be further understood, that to start the dental drill with accompanying air at the tip of the drill, the dentist would blow an impulse (not a continuous pressure) through the mouth piece to actuate the diaphragm and cooperating ratchet relay switch means which will run both an indefinite period of time until the relay is stepped again by a like impulse to turn the dental drill and accompanying air supply off. The same is true with a sucking impulse through the mouthpiece which turns on both the drill with accompanying air and water at the tip of the drill and the drill and actuated air and water supply will remain turned on until a second sucking impulse is received by the diaphragm control box. Thus, the dentist not having to maintain a sucking or blowing impulse on the diaphragm during the operation of the drill, may be freed for other duties, such as, talking to the patient during a drilling or cleaning operation.

In operation, this invention leaves the dentists hands and feet free of continued use of foot switches and hand control means so that the dentist may move freely about the patient and talk to the patient during drilling operations of the dental drill, permitting the dentists hands to be free to hold the dental drilling mechanism in various positions in the patients mouth and freeing the dentists hands of duties except the holding of the drill mechanism enabling the dentists hands to get the exact feel of the drilling tool during high speed grinding of a tooth, which is critical in operation of cutting depths within a tooth structure, as understood by those skilled in the art.

The present invention may be very conveniently used by a dentist who is disabled for health or accident reasons in his limbs.

It is therefore, a primary object of this invention to provide a mouth and air operated impulse control system for the dental engine and accompanying use of water and air supplied about the tip of the drill during drilling a patients teeth.

Another object of this invention is to provide a dental control system in which the dentists fingers are freed from holding down a control on the drill handpiece enabling the dentist to get the feel of a drilling operation on a pa-tients teeth and the like.

A further object of this invention is to provide a control system which will operate independently of foot operated control means or the dentist may still use foot control without operating any manual switch to actuate foot control. Therefore, both mouth control and foot control are instantly available for the convenience of the dentist at all times.

A still further object of this invention is to provide a control circuit which is free from danger of shock to a patient.

Another object of the invention is to provide an air actuated control system which is easily adapted to a conventional hand control or foot controlled switch means for an air driven dental engine and accompanying drill handpiece.

A further object of this invention is to provide a control system for an air driven dental turbine of a drill handpiece which is economical to produce, easy to maintain and substantially untiring to operate, leaving old foot control undisturbed in its operation.

Another object of this invention is to provide a relay control box which will handle the switching of other air turbines in the dentists office, if desired.

Further objects of this invention is to provide a control circuitry whereby an electrical impulse from a mouth operated switch or a foot operated switch will selectively turn on or off air or air and water to a dental turbine as desired by a dentist while working on a patient.

Still another object of the invention is to provide circuit means to convert the conventional on-olf foot switch to a locking on type switch which when actuated once will turn the drill on and the same will remain on without continuing pressure on the foot switch, leaving the dentist free to move about, the drill being turned off by a second actuation of the foot switch.

Still other objects of the invention reside in this dental drill impulse control system as embodied in a unique mouth actuated diaphragm and switch means isolated from the power circuit, having a minimum combination of elements, unique switching circuit arrangements, novel arrangement of parts, and stepping relay control circuits therefor.

In the drawings:

FIGURE 1 is a partial perspective view of the basic embodiment of a dental control system interconnected to the chair and dental drill handpiece being mouth operated by an attendant;

FIGURE 2 is a perspective view in partial section showing the mouthpiece communicating with the diaphragm chamber to selectively compress or depress the diaphragm to operate the three-wire switch connected thereto;

FIGURE 3 shows enclosure of the diaphragm mechanism and switch of FIGURE 2 connected to the relay operated control circuit to selectively control the operation of the air, air and water, and air driven turbine;

FIGURE 4 discloses how an attendant mouth operated switch and control circuit of the instant invention may be simply and economically connected to any installed threewire foot controlled system for a dental chair as illustrated in block form;

FIGURE 5 shows one arrangement of the ratchet relays and one switch with cooperating contacts therefor; and

FIGURE 6 shows a modified schematic circuit diagram of FIGURE 4 in which a three-pole-double-throw switch may be mounted on the relay control box or other suitable place and interconnected by a foot control switch to the circuit of FIGURE 3, as shown.

In the drawings like reference numerals refer to like parts of the invention.

In the drawings:

Referring to FIGURE 1, a dental chair 10a is being operated by a dental attendant 12 holding the mouth piece 14 connected by conduit 16 to diaphragm switch box 18 which is further connected by control cable 20 to ratchet relay control box 22. Relay box 22 is connected by control cable 24 to air turbine control box 26. Air turbine control box 26 is connected by air conduit 28 and water conduit 30 to the air turbine 32 and drill handpiece 34, of FIGURE 4, and is operated as hereinafter explained in connection with FIGURES 3, 4 and 6.

Referring to FIGURE 2, the pneumatic diaphragm and switch control means of this inventive control system comprises a diaphragm enclosure designated generally by reference numeral 36, comprising a cup-like enclosure portion 38 having a closed bottom 40 adapted to be secured by conventional means, such as screws means 41 or the like to a conventional base support, as best shown in FIGURES 3 and 4. The upper part of the enclosure portion 38 is comprised of a circumferentially and inwardly extending lip 40a and an outer circumferential threaded portion 42 which threadably mates with the inwardly threaded portion 46 of diaphragm retaining ring 44 of enclosure 36. Ring 44 of enclosure 38 has a circumferentially and inwardly extending lip portion 48 to sealably secure flexible and resilient diaphragm gasket 50 between lips or flanges 40a and 48. The central portion of diaphragm gasket 50 is sealably secured by aperture (not shown) to a threaded base member or washer 52, as shown in FIGURE 3, which is fixedly secured in any conventional manner to shaft 54 which distally terminates in a shoulder portion 55 integrally connected to a smaller shaft end 56 which extends through aperture 58 of switch blade 59 and is secured thereto in a conventional manner by a cotter key 60, pin or the like. Switch blade 59 ineludes contact 62 which when moved upwardly by diaphragm 50 contacts contact 64 of blade 66, and likewise, when moved downwardly contacts contact 68 of blade 70 of single-pole double-throw switch 72, of a suitable conventional type. Blades 59, 66 and 70 of switch 72 are spaced apart by insulation blocks 74 and 76 and externally covered by insulation 74a, which are all secured together by insulated pins 78 and 80, as shown. Blade 66 is electrically secured to cable wire 82. Blade 60 is like wise secured to cable wire 84, and blade 70 is secured to cable wire 86.

Switch 72 is electrically insulated from mouth piece 14 and container 36 by the non-conducting flexible diaphragm 50. Tube 16 is also preferably of an electrically non-conducting material such as rubber, neoprene and the like.

Tube 88 may be of any desired material and communicates with the internal space 90 of diaphragm enclosure 36 and terminates at an outer end which is suitably connected to a flexible conduit 16 having its distal end secured to mouth piece 14, as shown in FIGURE 2.

A blowing or mouth actuated air pressure impulse by attendant 12 of FIGURE 1 causes diaphragm 50 to deflect upwardly making contact 62 suitably engage contact 64. A sucking or vacuum impulse on mouth piece 14 by operator 12 causes diaphragm 50 to deflect downward allowing contact 62 to engage contact 68, as will be more fully explained in connection with FIGURE 3.

Referring to FIGURE 3, a schematic wiring diagram is shown of the circuit for operating the air and water solenoid valves 92 and 94, respectively, which are located in the air turbine control box 26 of FIGURE 1, in which compressed air is used for energizing the dental turbine 32 of FIGURES l and 4, and voltage stepdown transformer 96 is energized by leads x and y which energizes the lower voltage control circuit comprising conventional stepping relays 93 and 100 for selectively controlling the air and water solenoid valves 92 and 94, respectively, to the dental handpiece which are in turn all selectively controlled by impulses from the dentist through the air and mouth operated diaphragm 50 of FIGURE 2, as hereinbefore described.

The power circuit, in general, comprises leads 102 and 104 operatively connected to a suitable electrical power source (not shown). Leads x and y are connected to leads 102 and 104 to energize the primary winding 106 of transformer 96, as shown. Lead 102 is further connected in parallel with windings 108 and 110 of solenoid valves 92 and 94, respectively. Winding 108 is connected by lead 112 to lead 114. Lead 114 is further connected to switch 116 having a cam follower 116a which operates switch 116 between contacts 134 and 135, as shown. Lead 112 is further connected to switch 118 operated by armature actuated switch 101 of relay 100. Lead 136 is connected to switch 128. Switch 128 when closed on contact 126 connects lead 124 to lead 136. Lead 124 is further connected in parallel to leads 104 and 132. Lead 132 is further connected to contact 134 of switch 116. Solenoid coil 110 is connected to leads 102 and 136. Lead 112 is connected to solenoid coil 108 and is also connected by lead 114 to switch 116. Switch 116 is operated by armature 99b, shaft 99 and cam 99a of relay 98 between contact 134 and open contact 135, as shown in FIGURE 5.

Relays 98 and 100 may be of any conventional ratchet type relay, as desired. For example, they may be of a type similar to that as manufactured by Potter and Brumfield, AP Series, ratchet type (AP17A), as shown on page 1118, of The Radio Electronics Master Catalog, 28th Edition (1964), published by United Catalog Publishers, Inc., 645 Stewart Ave., Garden City, NY. Relays 98 and 100 may be also of an SR type with cams of various shapes as generally desired, some of which are illustrated by cams D, E and F of FIGURE 150, page 283 of Relay Engineering Reference Book, by Charles A. Packard, published in 1946 by Struthers-Dunn, Inc., 139 N. Juniper Street, Philadelphia, Pa.

Relays 98 and 100 are uniquely interconnected by control circuitry as shown in FIGURE 3.

Lead 86 of switch 72 is connected to contact point 138 which contacts movable switch means 140 through armature means 99b of relay 98. Switch 140 contacts open contact 137 when relay 100 is not operating to uniquely prevent operation of relays 98 and 100 at the same time. Switch 140 contacts contact 138 of lead 86, in FIGURE 3. Switch 140 is connected by lead 142 to the winding 100a of relay 100. Winding 100a is further connected by lead 144 in parallel to winding 98a of relay 98 and the secondary winding 107 of transformer 96. Winding 107 is further connected by lead 84 to switch 59 containing contact 62 of switch 72. The operation of armatures 99 and 101 and their switches are so interrelated in the circuit of FIGURE 3 that relays 98 and 100 cannot operate at the same time.

Lead 82 is connected by contact 150 to switch 148 of relay 100, as shown. Switch 148 is further connected by lead 147 to winding 98a of relay 98, as shown in FIG- URE 3.

As shown in FIGURE 3, switch 116 is operated by the armature 99b of relay 98 and shaft 99 through cam 9% which cause switch 116 to contact contact 134 of the power circuit; and switch 140 is similarly operated by cam 99d between contacts 138 and open contact 135. In operation, if cam 99e is of the alternate stepping type, the first blowing impulse on tube 88 will close contact 62 to 64 of switch 72 causing switch 116 to move from contact 135 to contact 134. The second blowing impulse will cause switch 116 to move up again to contact 135 and cut air off to turbine 32. Insulation collar 74a insulates switch 72 from diaphragm control enclosure 18. While contact 62 is in the open position, switch 128, operated by armature 100b and cam 101d contacts open contact 127, and switch 120, also operated by armature 100b and cam of shaft 101 contacts open contact 121, of the power circuit. Switch 148, also operated by armature 100b and cam 101b, contacts contact 150, as shown in FIGURE 3. Switch 148 operates between contacts 150 and 146 by cam 101b of shaft 101 rotated by armature 100b coacting with ratchet 101a, as shown.

Armature 99b of relay 98 operates switches 116 and 140, of FIGURE 3, through ratchet 99c, shaft 99 and contact cams 992 and 99d, respectively.

Armature 100b of relay 100 operates switches 120, 128 and 148 of FIGURE 3 through ratchet 101a, shaft 101, contact cams 1010, 101d and 101b, respectively, as shown in FIGURE 3.

Leads 104b, 11% and 136b may be suitably connected to another pair of air and water solenoid valves similar to valves 92 and 94, respectively, if desired.

Leads 112a, 130 and 136a may be suitably connected to the three terminals of an orthodox foot control switch (not shown), to operate solenoid valves 92 and 94 directly from the power circuit, in a conventional manner, if desired.

Leads 82a, 84a and 86a may be suitably connected with another diaphragm switch control box 18 for flexibility of operation of the dental turbine engine by the dentist.

Referring to FIGURE 4, it may be seen how simply and economically the diaphragm new switch control box 18 and relay control box 22 of this invention may be connected to points 8, 9 and of a conventionally installed foot controlled switch means and solenoid air and water control box 26 interconnected by air hose 28 and water hose 30 to the dental handpiece 34 containing therein a conventionally installed air turbine portion 32 connected to drill 32a.

The solenoid valves 92 and 94 and the relay control circuit of control box 22 are energized by leads 102 and 104 connected to a suitable source of electrical energy (not shown).

The operation of the components of FIGURE 4 are identical with those of FIGURE 3, as explained above. Switch 72 is insulated from control box 18 and diaphragm enclosure 36 by insulated bracket 39 being secured by screw means 41 to control box 18, of FIGURE 4.

Diaphragm control box 18, relay control box 22 and air and turbine control box 26 may be mounted in any position about a dental chair, as desired for convenience of the dentist. It is to be understood, however, that these units may also be attractively packaged as a single unit and mounted, as desired, by the dentist on or in close proximity to the dental chair within the purview of this invention.

Referring to FIGURES 5 and 3, ratchet relay 98, of FIGURE 5, is comprised of winding 98a having energizing leads 144 and 147 which actuates hinged armature means 9% hinged at point 99ba and has a distal end terminating in a bent portion 99b]; which contacts the teeth 99' of ratchet wheel 990 to turn shaft 99. Shaft 99 rotates cam contact means 992 fixed thereon having recesses 9911a and raised portions 99db which operates cam follower 116a fixed to contact means 116 to contact either contact means 134 or 135, as understood by those skilled in the art. In FIGURE 3, armatures 99b and 10011 may be of a reciprocating type as shown in the above publication of StruthersDunn publication for relays 98 and 100, respectively. The relay of FIGURE 3 is similar in structure and operation to relay 98. In operation, it takes one mouth pulse through tube 16 to energize relay 98 to rotate cam 99d through one tooth of rotation 99 as indicated by arrow w. In other words, it takes one mouth pulse to actuate relay 98 to close contact means with contact means 135 and another month pulse to actuate relay 98 to open contact 116 with relation to contact 135 and another similar pulse to allow contact 116 switch to contact contact means 134. Cam means99d may have intermediate land portions (not shown) to hold contact means 116 free of either contacts 134 and 135, if desired, as understood by those skilled in the art.

In FIGURE 3, switch means including cam follower means 140a is operated by cam means 99d between contracts 137 and 138 in a manner similar to that described for switch 116 above.

Armature 100b may be a hinged armature means as shown by armature 99b of FIGURE 5, or a reciprocating armature and pawl member 100b as shown in FIGURE 3, to operate ratchet wheel 101a to turn shaft 101 carrying'fixed thereon cam members 101b, 1010 and 101d to operate switch means 148, 120 and 128, respectively, between contacts 146 and 150; contacts 118 and 121; and contacts 126 and 127, as best shown in FIGURE 3.

In FIGURE 3, switch s may be used to connect line 102 to solenoid windings 108 and 110, as desired.

Leads 82, 84- and 86 may each be insulated and all be nested together in cable CE, as desired.

Leads 104, 112 and 136 may each be insulated and all be nested together in cable AB, as best shown in FIGURE 3.

FIGURE 6 discloses how three-pole-double-throw switch may uniquely be used to selectively connect elements 162 and 164 of foot switch 161 to leads to con tacts 166, 167 and 168 of leads 112a, 136a and 130, respectively, to operate solenoid valve means 92 and 94 of FIGURES 3 and 4 independently of the control circuitry of FIGURE 3. Switch element 162 when closed on contact 162a operates water solenoid valve 94 and switch element 164 when closed on contact 164a operates air solenoid valve 92 of FIGURES 3 and 4.

If switch means is thrown to the contact means 82b, 86b and 84b of leads 82a, 86a and 84a, respectively of FIGURE 3, then switch means 161 may be used to operate the control circuitry of FIGURE 3 including relays 93 and 100 by a touch or impulse of the operators foot on foot switch 161 creates an electrical impulse for the ratchet electrical impulse of relays 98 and 100 of FIGURE 3 in a manner similar to the electrical impulse created during control by mouth operated switch 72. Thus, either the mouth operated switch 72 or foot switch 161 may be alternately used by the dentist for such electrical impulse control at his convenience for movement about a patient in a dental chair during working on a patient. By using the impulse method of operating the control circuitry and relays 98 and 100 of FIGURE 3, by either mouth operated switch 72 or foot operated switch 161, leaves the dentist free for other duties while at work on a patient other than sucking or blowing to operate mouth operated switch 72 or the dentist continuously holding closed either of the foot switch elements 162 and 164 of conventional foot switch 161 by pressure from the dentists foot, permitting the dentist to have more freedom of movement while working on a patient in a dental chair.

Air solenoid valve 92 is connected by conduit 28a to a suitable supply of compressed air (not shown), and is further connected by conduit 28 to dental turbine 32 as shown in FIGURE 4. Armature 108:: is operated by winding 108 of solenoid valve 92.

Water solenoid valve 94 is connected by conduit 30a to a suitable water supply (not shown), and is further connected by conduit 30 through conventional dental handpiece 34 to a conventional water aperture for dispersal of the water about drill 32a, as best indicated in FIGURE 4. Armature 110a is operated by winding 110 of water solenoid valve 94.

It is to be understood that the sucking and blowing impulses on diaphragm 50 may be reversed in the opera tion of solenoid valves 92 and 94, if desired, without departing from the scope of the invention.

From the above description of the circuits of FIGURES 3 and 4, if a first blowing or compression air impulse is imparted by the mouth of the dentist to diaphragm 50, contact 62 contacts 64 electrically connecting leads 82 and 84, which energizes relay 93 actuating armature 99b and switch 140 to contact open contact 137, opening the energizing circuit to relay 100, and closes switch 116 on contact 134 of the power circuit to energize winding 108 and armature 108a of air solenoid valve 92 which supplies air to the dental turbine engine 32 of FIGURE 4.

If a first sucking or vacuum impulse is imparted by the dentists mouth through tube 88 to diaphragm 50, shaft 52, of FIGURE 2, closes contact 62 on contact 68 placing control leads 84 and 86 in circuit with the energized secondary winding 107 of transformer 96, which energizes winding 100:: of relay 100 and actuates armature to close switch 148 on open contact 146 to uniquely prevent relay 98 from being actuated, while at the same time armature 100b closes switches 120 and 128 on contacts 118 and 126, respectively of the power circuit energizing windings 108 and 110 of air solenoid valve 92 and water solenoid valve 94, respectively, to supply both air and water to the dental handpiece 34, of FIGURE 4.

The cam 99a of FIGURE 5 may be of a shape for operation in the circuit of FIGURE 3, so that when the first blowing impulse is given in tube 88 the double contact 62 rises up to contact 64. This causes current to flow from transformer 107 winding by lead 84 through contact 62 to contact 64 connected by lead 82 to switch 148 connected to lead 147 to coil 98a, through lead 144 and back to coil 107. This causes relay 98 to close switch 116 on contact 134 which causes current to flow from lead 104 connected to lead 132 to contact contact 134 through switch 116 to lead 114 to lead 112 to coil 108 to 102 which causes air to be delivered to dental handpiece 34. Also, this first blowing impulse as above causes switch 140 to drop out of contact with contact 138 and make contact with contact 137. This causes an open circuit to relay and it cannot be actuated until switch 140 is brought back in contact with contact 138. Thus, with this first blowing impulse as above, relay 100 is cut off from being actuated by an accidental sucking impulse. The only way it can be actuated is for the dentist to give another first blowing impulse which will cause the ratchet relay 98 to close switch 140 against contact 138. The same is true of sucking impulses.

In FIGURE 6 the invention also provides a means by which the dentist can still use the standard foot control switch 161 to turn the dental drill on with accompanying air or air and water therefor. The standard foot switch 161 customarily supplied with the dental air turbine, only works while the dentists foot applies pressure to this switch. By throwing switch to contacts 82b, 86b and 84b of FIGURE 6, standard floor switch 161 can be placed in action or closed by momentarily applying pressure to switch 161 which will cause the dental drill to come on and stay on until the dentist again steps on switch 161 which will open the circuit and stop the dental drill. Standard switch 161 has two ends and depending on which end is stepped on determines whether air or air and water is turned on. Thus, the dentist can operate switch 161 in the standard way directly from the power circuit by throwing switch to contacts 166, 167 and 168, or operate the dental drill by selective ratchet relays 98 and 100 of the control circuit as explained above for FIGURE 3.

While FIGURES l and 4 only show one relay control box for one dental chair, it is to be understood that one relay control box 22 may be wired in parallel with the power circuit to a plurality of dental chairs to selectively control by electrical impulses the dental drills for operation for each dental chair, by the mouth operated switch 72 or foot switch 161 from one relay control box 22, if desired, Within the purview of this invention.

From the foregoing it will now be seen that there is herein provided a mouth operated or foot operated control system for a turbine dental engine which accomplishes by electrical impulses all the objects of this invention during use, and others, including many advantages of great practical utility and commercial importance.

In all cases it is to be understood that the particular arrangements of the invention described herein are presented by way of illustration only, and not restriction, and that various other arrangements, variations and adaptations may be devised without departing from the true scope of the invention.

What is claimed is:

1. In combination with a dental turbine and drilling handpiece having compressed air supply means and water supply means thereto for discharge at the drilling tip, control means for the air and Water supply comprising solenoid valves for the water supply means and air supply means, electrical means for energizing said solenoid valves, relay means for selectively controlling said electrical means to said solenoid valves, mouth actuated diaphragm switch means for selectively controlling current to said relay means and said solenoid valves to supply air to a dental turbine engine and water and air to the tip of the drill during grinding of a tooth workpiece.

2. In combination with a dental turbine and drilling handpiece as in claim 1, including a foot control means connected in parallel with said mouth operated diaphragm switch means, said mouth operated diaphragm switch means having one electrical control circuit actuated by blowing into the diaphragm switch means to actuate a solenoid air valve to supply compressed air to said dental engine, said diaphragm switch means having a second electrical control circuit which is actuated by a sucking impulse of the attendants mouth on said diaphragm switch means to actuate solenoid valves to supply both air and water to the dental drill during operation.

3. In combination with a dental turbine and drilling handpiece as in claim 1, wherein said relay means comprises a first relay and circuit means for operating the solenoid valve of the air supply means, and a second relay and circuit means for selectively operating the air supply means and the water supply means independently of said first relay and circuit means.

4. In combination with a dental turbine and drilling handpiece as in claim 3, including insulation means therefor, wherein a dental attendant is electrically insulated from electrical shock therefrom.

5. In combination with a dental turbine and drilling handpiece as in claim 4, wherein said relay and circuits comprise control circuits, and transformer means energized by said electrical means to energize said control circuits.

6. In combination with an air turbine and drilling handpiece having a drilling and grinding bit, compressed air supply means and water supply means thereto, control means for the air and water supply comprising solenoid valves for the water supply means and air supply means, electrical energy means for energizing said solenoid valves, relay means for selectively controlling said electrical energy means to said solenoid valves, mouth actuated diaphragm switch means for selectively controlling current to said relay means and said solenoid valves to supply air to said turbine, and water and air to the tip of said bit during grinding of a workpiece.

7. In combination with an air turbine and drilling handpiece as in claim 6, wherein said mouth actuated diaphragm switch means includes circuit means having one electrical control circuit actuated by blowing into the diaphragm switch means to actuate said air solenoid valve, and another control circuit energized by a sucking impulse on the diaphragm switch for operating simultaneously said air solenoid valve and water solenoid valves to supply air and water to said bit during operation thereof.

8. In combination with an air turbine and drilling handpiece as in claim 7, including a power circuit, control circuit means connected by a transformer to said power circuit, said power circuit being operatively connected to said electrical energy means.

9. In combination with an air turbine and drilling handpiece having a drilling and grinding bit, compressed air supply means and water supply means thereto, control circuit means for the air and water supply comprising solenoid valves for the water supply means and air supply means, electrical energy means for energizing said solenoid valves, ratchet relay means for selectively controlling said electrical energy means to said solenoid valves, mouth actuated diaphragm switch means for selectively controlling current to said relay means and said solenoid valves to supply air to said turbine, and water and air to the tip of said bit during grinding of a workpiece.

10. In combination with an air turbine and drilling handpiece as in claim 9, including a power circuit, impulse operated control circuit means connected by a transformer to said power circuit, said control circuit being connected by said transformer to said power circuit.

11. In combination with an air turbine and drilling handpiece as in claim 10, including alternate switching means including circuit means and a foot switch means for selectively operating said compressed air supply means and said water supply means directly by said power circuit.

12. In combination with an air turbine and drilling handpiece and control as in claim 9, including alternate switching means including circuit means and a foot switch means for selectively operating said ratchet relay means by said foot switch means.

13. In combination with an air turbine and drilling handpiece as in claim 12, wherein a plurality of dental chairs may be selectively and simultaneously operate by said impulse control circuit means.

References titted UNITED STATES PATENTS 2,671,268 3/1954 Crawford 3223 3,035,349 5/1962 Reid et a1. 3223 3,313,025 4/1967 Hertz 3223 LOUIS G. MANCENE, Primary Examiner.

R. PESHOCK, Assistant Examiner.

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