US2855672A - Dental apparatus - Google Patents

Description

E. J. FRANWICK ETAL 2,855,672

DENTAL APPARATUS Oct. 14, 1958- v -4 Shets-Sheet 1 Filed Sept.-27, 1956 INVENTORS.

EDMOND (.LFRA NW/CK a/x/R/cHA RD A. 854/ ATTORNEYS.

, Oct. 14, 1958 .E. J. FRANWICK ETAL 7 ,8

' DENTAL APPARATUS- Filed Sept. 27, 1956 1 4 Sheets-Sheet 2 A IR 5 UPPLY WA TE R SUPPLY INVENTORS."

EDMOND J. FRANW/CK aqq'R/c/MRo A. 560

@W, M Y @M,

ATTORNEYS. v

E. J.)FRANWICK ETAL DENTAL APPARATUS Oct. 14, 1958 Filed Sept. 27, 1956 4 Sheets-Sheet 4 INVENTORS.

EDMOND d. a R/cHA FRANW/CK R014. 850

United States Patent DENTAL APPARATUS Edmond J. Frauwick, and Richard A. Beu, Buffalo, N. Y., assignors to Hanan Engineering Co. Inc., Buffalo,

Application September 27, 1956, Serial No. 612,431

7 Claims. (Cl. 32-28) This invention relates to dental apparatus and more particularly to an improved system for delivering fluid to the field of operation for cooling, debris removal, or the like.

It has long been recognized that frictional heat during tooth preparation is a major pain factor, and with higher operating speeds of modern dental engines, trauma to the tooth structure due to increased frictional heat has become an increased danger. Use of local anesthetics to eliminate discomfort to the patient reduces the need for time consuming rest periods for patient recovery but has the disadvantages that the tooth remains unprotected from actual structural damage due to heat and that the patient is unable to indicate when danger areas are being approached.

Hence, the delivery of a coolant to the area of operation is a highly desirable means of combating the frictional heat problem, since the heat source of the pain is removed without deadening the patients sensitivity to approach of danger areas, and at the same time, the trauma to the tooth structure due to heat is avoided. In addition to the foregoing, application of a stream of fluid coolant is effective to displace debris from the field of operation, providing clear visibility for the dentist so as to still further contribute to safe, speedy operation.

The requirements of different procedures and the preferences of different operators with regard to various procedures make it highly desirable thata selection of fluid coolants be available, namely, air alone, water alone, and air-water atomized spray, conveniently and rapidly selectable as different operations or stages of the same operation may require. The most desirable if not the only practicable location for the nozzle device for emitting the fluid coolant is on the dental tool hand piece itself. Certain problems arise, however, in providing such coolant facilities, since for efiicient cooling action and debris removal, as well as for maintaining clear visibility of the field of operation, each of the various streams must be sharp and well directed toward the burr, diamond point stone or other cutting tool, and at the same time, the hand piece must be maintained unencumbered by bulky coolant apparatus. Furthermore, to obviate the expense of replacing hand pieces and other equipment now in use, it is of course desirable that the coolant apparatus be adapted for installation as an external attachment to the existing equipment, and in such case minimal size and out-of-the-way location of the coolant apparatus is especially important, particularly as to the parts installed onthe hand piece.

The present invention provides an efficient coolant supply apparatus which may be readily added to existing dental units, forming an unobtrusive accessory to the same and providing the desired three-way selective coolant facilities while in no way encumbering the usual facilities of such a unit. An important feature of the system of the present invention is that it provides threeway coolant facilities at the hand piece by means of a Very small yet fully efficient nozzle member attached to the tool chuck end of the hand piece and requiring only two small supply conduits, so that no substantial bulk is added to the hand piece such as might obscure the view of the field of operation or interfere with manipulation of the hand piece in the usual manner. The apparatus proves also a compact and yet rugged control rnechanism which is adapted to be located remote from the hand piece at an unobtrusive position on the main structure of the dental unit, this control unit utilizing the basic facilities present on the dental unit to supply air and water through the two conduits to the aforesaid nozzle in proper proportions for generation of a finely atomized spray, or a well-defined, gentle stream of air or water, according to the coolant selected for use at the moment.

Accordingly, a major object of the present invention is to provide an improved dental apparatus for the supply and application of fluid as a coolant or the like.

Another object of the invention is to provide an improved miniature nozzle for a dental hand piece embodying facilities for generating well-defined streams of air, water, and atomized air-water spray in a selective manner.

Still another object of the invention is to provide an improved clip of minimum dimension for attaching a nozzle to a dental hand piece without creating an obstruction of any kind, the clip being readily attached and detached to and from a wide variety of different types of hand pieces in common use.

Another object of the invention is to provide a hand of coolant, in synchronism with the operation of the] dental engine of the unit.

Other objects of the invention will be apparent from the foregoing general discussion, the following detailed description and claims, and from the drawings, wherein:

Fig. 1 is an elevational view, partly broken away, of

a typical dental unit fitted with coolant supply apparatus in accordance with one embodiment of the invention;

Fig. 2 is an enlarged fragmentary detail of the hand piece of the unit of Fig. 1, showing hand piece portions of the coolant apparatus attached thereto and in operation; a v Fig. 3 is a detailed view similar to Fig. 2 but showing a contra-angle hand piece such as is commonly used alternately with the straight hand piece, and a preferred em bodiment of the nozzle of the invention as adapted for use on such a contra-angle hand piece;

Fig. 4 is a schematic diagram illustrating the organi.- zation of the control facilities of the apparatus of Fig. 1; v

Fig. 5 is an enlarged front elevation of the main control unit of the apparatus of Fig. 1, with the cover of the control partly broken away;

Fig. 6 is a sectional view taken about on line of Fig. 5; r

Fig. 7 is a fragmentary cross sectional view taken about on line VIIVII of Fig. 5;

VIVI

Figs. 8, 9 and 10 are side elevational, bottom plan,

and front end views, respectively, of the contra-angle type nozzle of Fig. 3, on a still further enlarged scale;

Fig. 11 is a front end view of the nozzle element of Fig. 2, on an enlarged scale;

Fig. 12 is a side elevation of the same, sectioned about along line XIIX[I of Fig. 11;

Fig. 13 is a still further enlarged perspective view of the orifice portion of the illustrated nozzle element for contra-angle hand pieces, taken with the nozzle element in inverted position; and

Fig. 14 isa; similarly enlarged perspective of the orifice portion of the illustrated nozzle element for straight hand pieces.

Referring more particularly to' the drawings, the typical dental unit illustrated in Fig. 1 comprises an equipment pedestal 20 housing the usual electric, water and air supply utilities and. mounting the dental engine 22 having the usual articulated engine arm 24' terminating in a hand piece 28. For greater clarity of illustration, the usual accessory table is omitted from the showing of the accessory table arm 26 as are numerous other accessory items usual on' a dental unit but irrelevant to the present invention. In the embodiment of the invention illustrated in Fig. 1 thecoolant apparatus comprises a control unit 30 attached to the cuspidor arm 32 of the dental unit, and a selector switch 34 mounted on the accessory table arm 26 and connected to the control unit 36 by a cable 36 for selection of the desired coolant under the master controlof the usual dental engine foot controller 38.

Whichever hand piece happens to be in use on the dental unit at the moment, illustrated in Fig. l to be the straight hand piece- 28, is fitted with the appropriate straight or contra-angle nozzle of the invention. Thus astraight nozzle 40 is applied to the straight hand piece 28 of Figs. 1 and 2, while a contra-angle nozzle 40' is attached to the well known, alternately used contra-angle type hand piece 28" of Fig. 3. In each case, the nozzle is connected by means of a dual passage plastic or other flexible conduit 42, 42' through a quick disconnection coupling 44 to the control unit 30, the coupling 44 being provided for rapid change of the nozzle-equipped hand pieces. The portion of the dual passage conduit upstream of the coupling 44'is sheathed in a flexible metal coil or other suitable conduit 46 whichis clamped to and becomes a part of the engine arm and dental unit pedestal as shown.

Referring now to the schematic diagram of Fig. 4, the control unit 30 is connected to the air pressure and water supply of the dental unit 48-50, air under pressure being conducted from the supply 48 through a shut-off valve 52, a throttling valve 54, and a solenoid valve 56 to one of the tubes 58' of the twin tube" conduit 42. The water supply 50 is connected through a shut-off valve 60 toan inlet manifold 62 supplying a spray water throttling valve 64 which is in turn connected to a spray water control solenoid valve 66 opening into an outlet manifold 68 and thence to the other tube 70 of the twin tube conduit 42. The inlet manifold 62 also opens into a throttling valve 72 for controlling the flow rate of water for a plain water coolant stream under the control of a solenoid valve 74 connected to the outlet manifold 68 and thence to the tube 70.

- In the schematic representation of Fig. 4, the control switch 34 is represented as a cam type switch having three normally open contactors 76, 78, 80 controlled by cams 82, 84, 86 inaccordance with the position of the control handle 88, sotliat when the control handle is turned to spray, contactors 76 and 78 are closed, when the control handle is turned to air, contactor 76 alone is closed, when the control handle is turned to water, contactor 80 alone is closed, and when the control handle is turned to off, none of the three cam controlled contactors are closed. As shown, the control switch 34 is connected to energize the air control solenoid 56 when the control switch is turned to air, both the air control solenoid 56 and spray water control solenoid 66 when turned to spray, and plain water control solenoid 74 when turned to water, power for this selective energization being taken from a standard house current supply existing in the dental unit and indicated'in the diagram at 90'under the ultimate control of the dental engine foot controller 38 illustrated schematically here by the normally open switch 92. Although the foot controller switch is illustrated for simplicity as a simple on-otf switch, it is understood of course that in the usual dental engine control the switch means corresponding to the illustrated switch 92 includes a number of circuit means for speed control and the like but insofar as its pertinency to the present invention is concerned, it may be considered as closing a circuit indicated at 94, 96 of the electric motor 98 of the dental engine 22, from which power may be taken for operating a device in synchronism with the dental engine. Thus, it will be understood that whenever the foot controller 38 isoperated to a dental engine energizing position, a dental engine operating circuit in the dental unit will become energized and, as will be readily understood by those skilled in the art, power so synchronized with the operation of the dental engine may be taken at a terminal in the dental unit as represented in the schematic diagram at 100. Where the dental unit to which the apparatus of the invention is applied has control circuits which result in voltage surges, it is preferred that the power taken from the dental engine synchronized source 109 be utilized merely to energize a relay 102 forming part of a control unit 36) and having a normally open contactor 104 controlling power from the supply 96, through a rectifier 106, where D. C. solenoid valves are used, to the selector switch 34. While a half wave rectifier is shown for simplicity of illustration, it will be understood that a bridge type full wave or other kind may be used, as desired.

From the foregoing it will be understood that operation of the solenoid valves 55', 66 and 74 will be synchronized with operation of the dental engine by the controller 38 subject to the closure of the corresponding hand switch contactors 76, 78, 88 as determined by the position of the handle 83 of the selector switch.

As will appear more fully hereinafter the collant nozzle 4t) or 46 of the invention is capable of delivering a well defined stream of cooling air when the solenoid 56 alone is open, a similar stream of cooling water when the solenoid valve 74 alone is operated, and a finely atomized air-water spray when solenoid valve 56 and 66 are energized simultaneously, the throttling valves 64 and 72 being set for low and higher rates of water flow, respectively, for delivery of proper amounts of water for the fine air-water spray and the plain water stream, respectively.

Aswili appear more fully hereinafter, the rates of flow delivered by the control 30 are small and require fine adjustment, and to enjoy the full benefits of the selective features of the invention means are provided whereby these adjustments may be made in a permanent manner in accordance with the preference of the operator. At the same time it is necessary that the control equipment be compact and reliable and adapted for attachment to the usual dental unit without in any way diminishing the utility of the other facilities of the same. To this end the control means of the unit 30 indicated in the scl1ematic diagram-of Fig. 4 are embodied in a compact and sturdy structure as shown in Fig. 5. Since the showing of Figs. 5, 6 and 7 is'directed primarily to the mechanical arrangement of the control unit 30, the wiring, which may be as in-Fig. 4, has been omitted to minimize confusion. As shown, the control unit comprises a coverlltl'mounted on a back or base member 112 which in turn is mounted on the cuspidor arm 32 of the dental unit, as by a bracket 114 and a resilient bumper 116. The principal element of the control is a grid-like structure comprising the three solenoid valves 56, 66, 74- mechanically interconnected at their inlet ends by an inlet conduit bar 118, which also mounts the inlet shut-off valves 52, 65). For supporting this structure the solenoid valves are bracketed about their mid-portions by a clamp structure comprising a forwardly directed U-shaped bracket spot welded or otherwise a'tfixed tdthe'back panel 112 and carrying a retainer bar 122,. and another back panel carried. U-shaped bracket member 124 having forwardly extending upper and lower legs slotted as at 126 to receive the inlet and outlet port members of the solenoid valves in bracketing relation, in which they are retained by the clamping. bar 122. For further rigidizing the aforesaid grid structure, the outlet portions of the two water solenoids 66, 74 are joined by an outlet conduit bar member 128.

The illustrated solenoid valves are commercially available purchased parts, and may be of the general kind shown in U. S. Patent No. 2,616,452, having inlet and outlet port members 130, 132, rigidly interconnected through end plates 134, 136 and a shell member 138, the end plates and shell member forming a housing for the solenoid 140, valve seat 142, and armature valve member 144. In the type of valve shown, the inlet port member incorporates the corresponding throttling valve 54, 64, 72 as a needle valve 146 interposed in the inlet bore 148, 150.

The inlet conduit bar 118 comprises a body bored transversely at positions corresponding to each of the inlet port members 130 and also at each of the shut-off valves 52, 60, the bodies 152, 154 of which are held recessed in notches 156, 158 in the bar 118 as shown. A plug- like member 160, 162, 164, or 166, 168 is passed through each of these transverse bores and threadedly engages in the inlet entrance portion of the corresponding inlet port member 130 or the outlet port of the corre sponding shut-off valve 52, 62, respectively. Accordingly, these plug-like members provide rigid interconnection between the inlet conduit bar 118, the inlet port members of the three solenoid valves, and the body parts of the two shut-off valves. In addition to providing mechanical rigidity, this structure carries the inlet flow of fluid to the control; for this purpose the joint at each of the plug-like members is sealed by rings as shown, and the conduit bar 118 has a bore 170 extending from one end to communicate between the positions of the pluglike elements 160 and 166, and another bore extending from the other end to form the water inlet manifold 62 communicating between the positions of the elements 162, 164, 168. The exterior ends of the bores 62 and 170 are closed by plugs 172, 174. To complete the communication through the two fluid inlet conduits so formed, each of the plug- like elements 160, 162, 164, 166, 168 is formed with a longitudinal bore 175 from its inner end communicating with a transverse bore 176 ending in an annular groove 178 in alinement with the conduit bore 62 or 170 as the case may be.

The outlet port members 132 of the water solenoid valves 66 and 74 are mechanically inter-connected in a similar fluid conducting manner, the outlet manifold bar 128 being transversely bored at positions corresponding to each of the outlet port members 132 of the two valves to receive plug- like members 180, 182. These plug-like 1 members extend through the outlet manifold bar into threaded connection with the outlet port member 132 of the corresponding valve, and have longitudinal and transverse fluid passageways 184, 186 for opening through an annular groove 1.88 into communication with a longitudinal bore in the bar forming the outlet manifold 68 as shown. It will be observed that all of the plug- like members 160, 162, 164, 166, 168, 180, 182 are identical with the exception that the members 166 and 168 are lightly shorter than the rest, approximately by the amount that the bodies of the valves 52, are set into the conduit bar 118.

The shut-oft valves 52, 68 are identical to each other, and the showing of Fig. 7 may be taken as representative of either, this figure showing the air inlet valve 52 as having a solid body 152 which is threadedly attached to the conduit bar 118 by the plug-like member 166 as before described and is longitudinally bored to house a valve seat member 190 threadedly engaged therein, being sealed thereto by 0 rings 192, 194 as shown.

Threadedly engaged in the valve seat member 190 is a needle type valve member 196, sealed thereto by 0 rings 198 and arranged to open and close communication through the valve upon the turning of a control knob 200. At the upstream end of the valve seat member, the same has a nipple projection mounting a collar 202 having an annular groove 204 mounting the edge of the open end of a hollow filter element 206. This filter element removes any particles that may be present in the fluid entering the inlet port of the valve 208 from the air supply of the dental unit, as indicated by the connection conduit 210, or in the case of the Water shut-otf valve 60, from a similar conduit connection (not shown) from the water supply of the dental unit.

Referring again to Fig. 5, the outlet port member of the air control solenoid valve 56 is fitted with a nipple member 212 connecting to an air outlet tube 214 to which the air tube 58 of the dual passage flexible conduit 42 is connected, and the water tube 70 of the conduit 42 is fed in like manner through a tube 216 and a nipple connector 218 to the outlet manifold 68 of the water valve assembly. Accordingly it will be seen fluid flow passages are provided through the control unit 30 for water, as shown by the arrows 220, 222, and for air as shown by the arrows 224, in accordance with the flow pattern of the schematic diagram of Fig. 4.

In addition to the fluid conducting mechanism 7 described, the control unit 30 houses the rectifier 106, the relay 102 and a connection terminal block 226.

Referring now to the nozzles of the apparatus, the contra-angle type nozzle 40 as shown in Figs. 8, 9 and 10 comprises a pair of tubes 230, 232 for air and water as delivered by the twin tube conduit 42, soldered or otherwise joined to a mounting clip 234. The mounting clip has a plurality of opposing spring legs 236, 238, 240, 242 arranged in planes transverse to the tubes 230, 232 as shown and third pair of spring legs at the end of the noz zle member whose root portions 248, 250 are disposed similarly to the previously mentioned spring legs but mount forwardly extending ears 250, 252. Accordingly when the clip is installed on a contra-angle type head asshown, the several spring legs embrace the head portion 254 and the adjacent neck portion 256 of the hand piece, independently accommodating to the irregularities of the hand piece. Contra-angle hand pieces in wide use are made in a variety of conformations, but it is general that at the drill chuck or head end portion the sides of the tool head are arranged in more or less parallel planes, or comprise a cylindrical conformation coaxial with the drill presenting an outline transverse to the general axis of the hand piece, and the forwardly extending ears 250 grasp these transverse surfaces or outlines thereby providing positional stability to the clip against twisting motions about the major axis of the hand piece. It will be seen that, by reason of the many closely arranged but independently sprung legs, the clip can accommodate to a wide variety of contra-angle hand piece shapes.

The nozzle tubes 230, 232 are closed at their outer ends and are provided with small orifice ports 260, 262 which are angularly directed outwardly toward the end of the clip and inwardly toward each other so as to be directed approximately toward the end 264 of the usual tool when the same is in use in the hand piece to which the nozzle is applied.

As shown at 265 the space between the tubes in the region of the orifices is partly filled in with solder or the like and a groove 266 is provided transverse of the tube assembly slightly forward of, but is close as practicable to, the orifices 260, 262. This groove constitutes an important feature of the invention, providing a complex action which conducts the water from its orifice to the stream of air emerging from the other orifice as illustrated in Fig. 13, wherein the nozzle is shown in air- Water spray generating operation. It is believed that the function of the groove 266 is to provide a combined damming, capillary and windage directing action with the result that the water follows a course generally as indi-- cated by the arrow 268, being conducted from the water orifice to the air stream instead of being lost off the end of the nozzle element.

As shown by the dotted line 270, when the water and air are turned ofi, as by release of the dental engine foot controller, the elasticity of the conduit 42 causes a slight additional discharge of water and this water builds up in a pool generally between the groove 266 and the transverse edge 272 of the nozzle clip at the other side of the orifices. Accordingly any tendency to establish a wet drip path off the end of the nozzle element is minimized, and in any event when the spray is again put into operation the water is quickly removed by the air stream to establish a steady state situation as shown by the shading 274, that is a visible wetness at the end of the groove 266 adjacent the water orifice, with the film of water progressively thinning toward the air orifice. Accordingly the groove 266 is, in cooperation with the surrounding edge 272 of the clip, a water confining element, and more importantly, the groove acts as a water flow directing and conducting element to convey the water to the air orifice where it is picked up by the air stream by a kind or" aspirator action. At the same time the groove is entirely external of the water and air orifices so that the stream path from these orifices is entirely open when air or water alone are used in accordance with the selective control of the invention. Accordingly the air and water streams when used alone are entirely undisturbed by the atomized spray forming elements.

Referring now to Figs. 10, 12 and 14, the above described principle is embodied in the nozzle 40 for the straight hand piece in the form of a groove 280 traversing the ends of the water and air tubes 282, 284 and into which the water and air orifices 286, 288 open. It is believed that the physical principles involved in the operation of this hand piece are the same as those described in connection with Fig. 13, it having been observed that during air-water atomized spray operation a thin film of water is present in the groove 280 adjacent the water orifice and this film becomes progressively thinner toward the air orifice, as shown in Fig. 14. Thus it is evident that there is a Water flow along the line indicated at 290, conducting the water from the water orifice to the air stream to provide a fine Well directed spray in the same manner as the contra-angle nozzle of Fig. 13. As in the contra-angle type nozzle, when the spray is turned ofi, a small amount of water builds up in the groove 280, but this is rapidly removed upon operation of the unit without any substantial tendency to establish a drip path which would disturb the spray.

Also similarly to the contra-angle clip, the straight clip as illustrated in Figs. 11 and 12 comprises a plurality of pairs of opposed spring arms 2%, 2%, 2%. 300 arranged to embrace the head of the straight hand piece as shown in Fig. 2, the body 292 of the clip being soldered or otherwise attached to the twin tubes 302, 3&4 of the nozzle. As in the contra-angle hand piece, it is preferred that, whether solder or some other method of attachment is used, the spaces between the tubes at the water air spray forming slot 280 be filled in somewhat, as shown at 306, to provide continuity to the slot.

It will be seen that in each form of the nozzle of the invention, the orifices open into contiguous relation with the water flow directing groove. In the straight type nozzle 40, these openings are in the groove itself, and this relationship could be employed, although with a less than fully efficient effect, in the contra-angle type of nozzle 40. Actually, although the orifices in the contra-angle nozzle are located adjacent to the groove, it must be remembered that the size of the nozzle is quite small and that the actual relation of the orifices and the groove in this nozzle is one of very close proximity, which, taken together with the angular relation of the orifice which happens to be conducting water, results in effective delivery of the water directly to the groove. For example, in one highly efficient production model of the contra-angle clip 40 the oriffices 260, 262 are 0.0135 inch in diameter, spaced 0.065 inch apart and located as close as practicable to the groove 26o, that is with a spacing of about 0.005 to 0.010 inch between the edge of each orifice and the adjacent edge of the groove. The groove of the aforesaid model itself is small enough to have considerable capillary action as aforesaid, being about 0.015 to 0.025 inch wide and 0.010 to 0.015 inch deep.

The effectively contiguous adjacent relation of the water bearing orifice to the groove in the contra-angle nozzle is preferred to actual location in the bottom of the groove since it has been found that with the latter location the water emerging from the angularly directed nozzle has some tendency to jump the groove and be lost in part off the end of the nozzle structure. However, even with the preferred adjacent relationship of the nozzle orifice shown, it is necessary for full efliciency only that the water emitting orifice be contiguously adjacent to rather than in the bottom of the groove, both orifices being located in this position simply to make them fully interchangeable so that no care need be taken in connecting the conduit 42, particularly at the quick disconnection coupling 44.

It will be appreciated that numerous other variations can be made without departing from the spirit of the invention. For example, the exact form of the spring legs of the nozzle clip members is not mechanically important, the principle being that a number of separately spring biased grasping members are provided in spaced relation to conform to irregularities of the hand piece, the forward pair of such members having forwardly extending portions in the case of the contra-angle type clip. However, the form of each of these legs can vary widely; for example, they could be made simply from pieces of spring wire, or they could be articulated parts mounting pads at their extremities for grasping the hand piece head and neck portions.

From the foregoing it will be appreciated that a highly flexible and convenient apparatus is provided for supplying fluid to the area of operation as a coolant and/or for debris removal. This results from the capability of the nozzle for providing a clean, sharp jet of air alone, a similar stream of water alone or a spray of finely atomized air-water spray while providing this three-way operation with a supply means of only two conduit passageways and yet without requiring any selective valving or other adjustable mechanism on the hand piece, together with the provision of a compact, rugged control capable of providing the pressures, such as the low pressure water for atomized spray and the higher pressure water for a free water stream, required for this threeway operation.

While only one form of the complete apparatus of the invention, embodying only two forms of the three-way nozzle of the invention, has been shown and described in detail it will be understood that the invention may be otherwise embodied within the spirit of the invention and the scope of the appended claims.

What is claimed is:

1.In a dental apparatus adapted to be applied to a dental unit having air supply means, water supply means and a dental engine having a hand piece, control means adapted to be connected to said air and water supply means and comprising a first solenoid valve adapted to adjustably control flow of air from said air supply means, and second and third solenoid valves connected in parallel and adapted to separately adjustably control flow of water from said water supply means, first and second flexible conduits arranged to conduct flow from said first valve and the parallel combination of said second and third valves, respectively, to said hand piece, nozzle means connected to said conduits and adapted to be mounted on said hand piece and comprising means providing first and second nozzle orifices connected respectively to said conduits and means providing an open external conduction path for water from said second orifice to the periphery of said first orifice, and electric control means comprising a switch adapted to operate said first valve alone to open position, said third valve alone to open position, and said first and second valves to open position simultaneously, in a selective manner.

2. A nozzle element for use in a dental apparatus for applying fluid from a dental engine hand piece to the field of operation, comprising a dual passage conduit body, said body being formed with a pair of adjacent orifices opening from the respective passages thereof and directed to converge on a tool in use in the hand piece to which the nozzle element is applied, and said body being formed with an open groove having a wall contiguous with each of said orifices adapted to join them and direct a water flow path from one of said orifices to the other for forming a spray.

3. A nozzle element for use in a dental apparatus for applying fluid from a dental engine contra-angle hand piece to the field of operation, comprising a dual passage conduit body, said body being formed with a pair of adjacent orifices opening from the respective passages thereof and directed at an angle outwardly along the nozzle element and inwardly toward each other to converge on a tool in use in the hand piece to which the nozzle element is applied, and said body being formed with an open transverse groove in the lateral face of said body bearing said orifices and located immediately forward of at least one of said orifices, said groove having a wall contiguous with each of said orifices and being adapted to join them and direct a water flow path from said one of said orifices to the other.

4. A nozzle element for use in a dental apparatus for applying fluid from a dental engine straight hand piece to the field of operation, comprising a dual passage conduit body, said body being formed with an open groove across its outer end and said body being formed with a pair of adjacent orifices opening from the respective passages thereof into the base Wall of said groove, said groove being adapted to join said orifices and direct a water flow path from one of said orifices to the other.

5. A nozzle element for use in a dental apparatus for applying fluid from a dental engine hand piece to the field of operation, comprising a dual passage conduit body, said body being formed with a pair of adjacent orifices opening from the respective passages thereof and directed to impinge on a tool in use in the hand piece to which the nozzle element is applied, and said body being formed with an open groove having a wall contiguous with each of said orifices adapted to join them and direct a water flow path from one of said orifices to the other.

6. In a dental unit, air supply means, water supply means and a dental engine having a hand piece, control means connected to said air and water supply means and comprising a first solenoid valve adapted to adjustably control flow of air from said air supply means, and second and third solenoid valves connected in parallel and adapted to separately adjustably control flow of water from said water supply means, first and second flexible conduits arranged to conduct flow from said first valve and the parallel combination of said second and third valves, respectively, to said hand piece, nozzle means connected to said conduits and mounted on said hand piece and comprising means providing first and second nozzle orifices connected respectively to said conduits and means providing an open external conduction path for water from said second orifice to the periphery of said first orifice, and electric control means comprising a switch adapted to operate said first valve alone to open position, said third valve alone to open position and said first and second valves to open position simultaneously, in a selective manner in synchronism with said dental engine.

7. In a dental apparatus adapted to be applied to a dental unit having air supply means, water supply means and a dental engine having a hand piece, control means adapted to be connected to said air and water supply means and comprising a first solenoid valve adapted to adjustably control flow of air from said air supply means, and second and third solenoid valves connected in parallel by inlet and outlet manifold members and adapted to separately adjustably control flow of water from said water supply means, said manifold members acting as structural members to support said second and third valves, first and second flexible conduits arranged to conduct flow from said first valve and said outlet manifold, respectively, to said hand piece, nozzle means connected to said conduits and adapted to be mounted on said hand piece and comprising means providing first and second nozzle orifices connected respectively to said conduits, and electric control means comprising a switch adapted to operate said first valve alone to open position, said third valve alone to open position, and said first and second valves to open position simultaneously, in a selective manner, said inlet manifold member having a structural extension supporting said first valve and forming the inlet .conduit thereto, and air and water inlet shut ofi valves mounted by said inlet manifold member and connecting therethrough to said inlet conduit and said inlet manifold, respectively.

References Cited in the file of this patent FOREIGN PATENTS 483,400 Germany Oct. 1, 1929

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