FIELD OF THE INVENTION

The present invention relates to dental handpieces incorporating high speed turbines, and more particularly concerns a dental handpiece with a removable turbine housing.

BACKGROUND OF THE INVENTION

Many dental handpiece devices have been proposed in the prior art for use in removing carious material and preparing teeth for the application of various dental treatments. Most of these devices comprise a substantially cylindrical elongated handle including a plurality of elongated conduits therethrough, and having connection means at a proximate end for allowing communication between said conduits and sources of turbine impelling fluid, water, air, light, or the like. At the distal end of such handpieces is generally found a turbine housing permanently affixed to the handle, in which housing is mounted a high speed turbine. Recent increases in the public awareness and concern over infection control procedures used by dentists has led the American Dental Association to put in place fairly rigorous requirements conceming the post-use cleaning of dental handpieces. Such requirements have increased significantly the maintenance costs associated with these devices. One particular requirement in the standard cleaning procedure for dental handpieces is that such handpieces be autoclaved after each use, whereby the devices are subjected to sufficiently high temperatures for killing most infectious micro-organisms which may be found within such dental handpieces. Because the cleaning procedures prior to such autoclaving are not capable of removing all bio-matter from dental handpieces having high speed turbine assemblies (especially in internal areas of the turbine), such bio-matter is actually baked onto various components of these handpieces by this cleaning procedure. Understandably, this eventually leads to the need for sending these instruments to an industrial cleaning facility where the instruments are

taken apart for the cleaning or replacement of various parts which the dentist is unable to care for.

The public concern over infection control and the increase in maintenance costs associated with dental handpieces that has been precipitated by such concern, has led to a need for dental handpieces which can be more easily and economically cleaned and maintained. This need has precipitated various attempts to provide a dental handpiece having a disposable turbine assembly. Two basic schools of thought pertaining to the provision of such a handpiece are prominent in the art. 1 ) provide a dental handpiece having a permanent handle with an openable turbine housing, into which housing can be emplaced a removable turbine cartridge; and 2) provide a dental handpiece having a permanent handle and connection means to which a disposable turbine housing with enclosed turbine assembly may be removably affixed. Examples of devices which exhibit the first school of thought can be found in the following U S Letters Patent: #4,071 ,954 by Eibofner; #4,219,330 by Jaremus; #4,231 ,739 by ludica; and #5,252,065 by Nakanishi. Unfortunately, none of these devices has been commercialized successfully. The inventor believes that two key problems behind such lack of success with these devices concern the general difficulty in handling such small cartridges, and the high costs associated with the manufacture of such cartridges.

In order to overcome these problems, teachings of the earlier noted second school of thought have been proposed. Examples of devices which exhibit the second school of thought can be found in the following U S Letters Patent: # 3,955,284 by

Balson; and #5,252,067 by Kakimoto. Although the devices of Balson and Kakimoto provide a dental handpiece having a permanent handle with means for connecting to it a disposable turbine housing with turbine assembly, neither of these devices has been commercialized successfully. The inventor believes that the key concerns which have prevented these devices from achieving such success include the high costs associated with manufacturing each removable turbine housing, the difficulty with which each turbine housing is emplaced upon the permanent handle, and a deficiency in the stability of the connection between the turbine housing and the permanent handle. After reviewing the ensuing descriptive matter and illustrations conceming the instant invention, those skilled in the art will recognize that while the dental handpiece devices of the prior art which include high speed turbine assemblies may be suitable for a particular purpose to which they address, it will be apparent that said devices would not be as suitable for the purposes of the present invention.

SUMMARY OF THE INVENTION

In view of the foregoing disadvantages inherent in the known types of dental handpiece devices now present in the art, the invention disclosed herein provides an improved and enhanced dental handpiece with removable turbine housing. The instant invention comprises a permanent handle in which the only moving parts are attachable connectors for communicatively joining the handpiece to various fluid intake and exhaust tubes, water tubes and optic fibers; and a disposable head assembly which includes a turbine, bearings, a dental bur, means for increasing the kinetic energy of a column of fluid being directed at the turbine and an exhaust channel. A unique tensioned suspension system has been incorporated into the design of the head assembly for insuring a secure connection between the head assembly and the handpiece. The design for the suspension system is adapted around a unique rigid "proboscis" which extends from the handpiece and which includes a channel for extending therethrough various misting and optic-fiber means. By furnishing such a channel in the proboscis, rather than incorporating such misting and fiber-optic means into the disposable head assembly, cost efficiencies are obtainable which are far beyond those which have been available in disposable head assemblies of the prior art. Also, the uniquely snug fit between the disposable head and the handpiece of the instant invention, further provides the operator with a tactile sensitivity significantly greater than that which has been available through dental handpieces of the prior art which incorporate disposable head assemblies.

The instant invention further includes a new and improved high speed turbine housed within the disposable head assembly, which turbine includes means for dividing and rechanneling a stream of fluid impelled upon it from an intake port of the head assembly. The impelling fluid stream is divided into a plurality of smaller, vortic fluid masses which are further spun about the periphery of the turbine housing and expelled efficiently from said housing into the exhaust port of the disposable head assembly. Still further provided in the instant invention is a unique pair of self-aligning bearing races, which are designed to compensate for manufacturing variances between the components of the disposable head assembly. The unique design of the bearing races further allow for the use of far fewer components, and thereby the achievement of much greater cost

efficiencies, in the disposable head assembly than that which is available in disposable head assemblies of the prior art.

Upon a closer review of the more detailed description herein, those skilled in the art will recognize that the concepts of the present invention easily overcome the problems described above which have been heretofore commonly associated with dental handpiece devices. As such, the general purpose of the present invention is to provide a new and improved dental handpiece with removable turbine housing which has all the advantages of the prior art and none of the disadvantages.

It is an additional object of the present invention to provide a new and improved dental handpiece with removable turbine housing, which handpiece is easily cleaned and maintained.

It is an additional object of the present invention to provide a new and improved dental handpiece with removable turbine housing including means whereby said housing may be affixed to the handpiece in a secure manner.

It is a further object of the present invention to provide a new and improved dental handpiece with removable turbine housing, which dental handpiece includes an extension arm or proboscis for extending various misting and lighting means through the turbine housing directly to the dental site at which an operator is engaged, and thereby avoiding the costs associated with including such misting and lighting means as a component of the removable turbine housing. It is a further object of the present invention to provide a new and improved dental handpiece with removable turbine housing which provides the operator a higher degree of tactile feedback than that which is provided in dental handpieces having a removable turbine housing of the prior art.

It is a further object of the present invention to provide a new and improved dental handpiece with removable turbine housing, including an ergonomically shaped handle which provides the operator a higher degree of tactile angular information conceming the angular positioning of a dental bur extending from the turbine housing than that which is provided in dental handpieces having a removable turbine housing of the prior art.

It is another object of the present invention to provide a new and improved dental handpiece with removable turbine housing which may be easily and efficiently manufactured, marketed and installed.

It is still a further object of the present invention to provide a new and improved dental handpiece with removable turbine housing which is of durable and reliable construction.

It is yet still a further object of the present invention to provide a new and improved dental handpiece with removable turbine housing which meets all federal, state, local and other applicable governing body statutes, regulations, private standards, guidelines, and industry recommendations with respect to health, safety, environmental responsibility, energy conservation, etc.

An even further object of the present invention is to provide a new and improved dental handpiece with removable turbine housing which is capable of being manufactured at a low cost with regard to both materials and labor, and which accordingly is then marketable at low prices of sale to the consuming public, thereby available to the buying public.

These together with other objects of the invention, along with the various features of novelty which characterize the dental handpiece with removable turbine housing of the present invention, are pointed out with particularity in the claims appended hereto and forming part of this disclosure. The more important objects of the present invention have been outlined rather broadly in order that the detailed description thereof which follows may be better understood, and in order that the present contribution to the art may be better appreciated. For a better understanding of the instant invention, its operational advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated various embodiments of the invention.

Those versed in the art will readily ascertain, however, that the present invention is capable of other embodiments and of being practiced and carried out in various other ways. In this respect, the details of construction disclosed herein, including the component materials and the arrangements of the components set forth in the following description and appended drawings, are for illustrative purposes, only, and are not intended to be limiting in scope. Those skilled in the art will appreciate, as well, that the conception upon which this disclosure is founded, may be readily utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. Said other structures may include, but are not limited to, those which are aesthetic in nature, or those which include the substitution of other materials as they become available, and which perform substantially the same function in substantially the same manner with substantially the same result as the present invention. It is important, therefore, that the claims appended hereto be regarded as including such equivalent materials,

structures, constructions, methods, and systems insofar as these do not depart from the spirit and scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description. Such description makes reference to the appended drawings, wherein: Fig. 1 is a side elevational view of an embodiment of a dental handpiece with removable turbine housing, according to the present invention; Fig. 2 is an exploded perspective view of a portion of the embodiment of the dental handpiece with removable turbine housing of Fig. 1 (minus part of the handpiece);

Fig. 3 is a top elevational view of the dental handpiece embodiment of Fig. 1 , with a portion of the plurality of internal passageways illustrated in phantom; Fig. 4 is a side elevational view of the dental handpiece embodiment of Fig.

1 , with a portion of a plurality of internal passageways illustrated in phantom;

Fig.'s A - F of Fig. 4 are various cross section views of the dental handpiece embodiment of Fig. 1 , illustrating the changing cross section shapes of the handpiece and the internal passageways extending throughout the handpiece; Fig. 5 is a bottom elevational view of the dental handpiece embodiment of

Fig. 1 , with a portion of the plurality of internal passageways illustrated in phantom; Fig. 6 is a top elevational view of the removable turbine housing embodiment of Fig. 1 ;

Fig. 7 is a cross section view of the removable turbine housing embodiment of Fig. 6, along line 7 - 7;

Fig.8 is a bottom elevational view of the removable turbine housing embodiment of Fig. 6;

Fig. 9 is an enlarged proximate-end elevational view of the removable turbine housing embodiment of Fig. 6, along line 9 - 9; Fig. 10 is a partial cross section view of the removable turbine housing embodiment of Fig. 7, along line 10 - 10;

Fig 11 is a partial cross section view of the removable turbine housing embodiment of Fig. 10, along line 11 - 11 ;

Fig. 12 is an enlarged cross section view similar to that in Fig. 7, of the removable turbine housing embodiment of Fig. 1 , and a similarly enlarged side

elevational view of a portion of the dental handpiece embodiment of Fig. 1 connected thereto in operable position;

Fig. 13 is an enlarged partial cross section view similar to that of Fig. 12, of another embodiment of a dental handpiece with removable turbine housing, according to the present invention; Fig. 14 is an enlarged partial cross section view similar to that of Fig. 13, of still another embodiment of a dental handpiece with removable turbine housing, according to the present invention;

Fig. 15 is an enlarged side elevational view of an upper self-aligning bearing race embodiment of the disposable head assembly embodiment of Fig. 2; Fig. 16 is a top elevational view of the upper self-aligning bearing race embodiment of Fig. 15;

Fig. 17 is a cross section view of the upper self-aligning bearing race embodiment of Fig. 16, along line 17 - 17;

Fig. 18 is an enlarged side elevational view of a lower self-aligning bearing race embodiment of the disposable head assembly embodiment of Fig. 2;

Fig. 19 is a top elevational view of the lower self-aligning bearing race embodiment of Fig. 18;

Fig. 20 is a cross section view of the lower self-aligning bearing race embodiment of Fig. 18, along line 20 - 20; Fig. 21 is an enlarged cross section view of the turbine and bearing assemblies of the disposable head assembly embodiment of Fig. 2, illustrating the upper bearings set in a first operable position within the upper bearing race, and the rotor with turbine and lower bearing race set in a position corresponding to said first operable position; and Fig. 22 is a cross section view similar to that of Fig. 21 of the turbine and bearing assemblies of the disposable head assembly embodiment of Fig. 21, illustrating the upper bearings set in a second operable position within the upper bearing race, and the rotor with turbine and lower bearing race in a position corresponding to said second operable position.

DETAILED DESCRIPTION:

The present invention comprises an improved dental handpiece with removable turbine housing assembly, including a permanent handle having a plurality of conduits or channels which extend longitudinally therethrough, a rigid extension arm or "proboscis" extending distally and axially from a distal end of the handle, and

means for securing to the handle distal end and proboscis a removable turbine housing which may be adapted for disposal after limited use. Said plurality of handle channels include separate turbine impelling fluid intake and exhaust channels, at least a cooling water/misting air channel through which an insertable water or air conduit may be extended for dividing said air from said water, and optionally a fiber-optic channel. The air-and-water and the fiber-optic channels extend through both the handle and the proboscis for communicating directly with a dental work area to which a bur extending from a turbine mounted in the turbine housing may be applied. The turbine housing comprises a turbine chamber that is affixed to an elongate handle engaging member, through which engaging member the proboscis of the dental handpiece may be extended for placing the turbine housing into operable position in communication with the handle distal end and proboscis. Said turbine housing further includes separate turbine impelling fluid intake and exhaust channels for communicating between the turbine chamber and similar channels of the handle. The turbine housing may optionally include means for increasing the kinetic energy of a column of turbine impelling fluid passing through the impelling fluid intake channel toward the turbine chamber.

Also, the removable turbine housing assembly may optionally include a new and improved high speed pneumatic turbine housed within the turbine housing, which turbine includes means for dividing and rechanneling a column of fiuid impelled upon it from the fluid intake channel, for efficiently moving said fluid about the internal periphery of the turbine housing and into the fluid exhaust channel. The turbine housing assembly still further may optionally include a unique pair of self-aligning angular contact bearing races, which are designed for overcoming dimensional variances between the various components of the turbine housing assembly, which variances may result from the high speed mass production of such components.

Various embodiments of the invention are illustrated in the appended drawings and described in greater detail, below. (All like numerical designations in the figures represent the same or a similar element.)

Fig.'s 1 through 22 illustrate an embodiment of a dental handpiece with removable turbine housing assembly 10 according to the present invention. For purposes of clarity, the terms "lower" or "downward" as used herein make reference to the direction in which a dental bur would extend from the turbine housing of the assembly 10 when the bur is affixed in operable position to a turbine mounted in operable position inside the turbine housing. Further, the terms "upper" or "upward" as used herein make reference to a direction which is opposite that in which a dental bur would extend from the turbine housing of the assembly 10 when the bur is affixed

in operable position to a turbine mounted in operable position inside the turbine housing.

In Fig. 1 is illustrated a removable turbine housing 21 mounted in operable position on a handpiece 23 of the dental handpiece with removable turbine housing assembly 10, while the remaining Fig.'s 2 through 12 illustrate various features of the turbine housing 21 or handpiece 23. In accordance with the present invention, the handpiece 23 of the assembly 10 comprises a handle 25 with extension arm, or proboscis 27. The proboscis 27 is affixed to the handle 25 at a distal end 29 of the handle 25, which distal end 29 is substantially planar and perpendicular to an axis of the handle 25. The proboscis 27 has a cross section area which is substantially less than that of the handle 25, and further extends distally from the distal end 29 in a line that is substantially parallel to the axis of the handle 25.

A plurality of channels extend longitudinally through the handle 25 from a handle proximate end 31; said channels including a turbine impelling fluid intake channel 33, a turbine impelling fluid exhaust channel 35, at least a cooling water/misting air channel 37 through which an insertable water or air conduit such as those which are known may be extended for dividing said air from said water, and an optional fiber-optic channel 39. While the turbine impelling fluid channels 33 and 35 extend to, and terminate at, the distal end 29, the air-and-water channel 37 and the optional fiber-optic channel 39 continue past the distal end 29 and through the extension arm or proboscis 27, to a proboscis distal end 41. Those skilled in the art will recognize that by extending said channels 37 and 39 through the proboscis 27, rather than incorporating such misting and fiber-optic means into the removable turbine housing 21, as taught in the prior art, cost efficiencies are obtainable in the manufacture and use of the instant invention which are far beyond those that have been available in removable turbine assemblies of the prior art.

Referring to the side elevational view of Fig. 4, it will be noted that the axis of the handpiece 23 follows substantially a straight line from the handle proximate end 31 to a first reference plane 43 in close proximately to the handle distal end 29, at which plane 43 said axis is angled upward about fifteen degrees (15°). After said fifteen degree angle, the handle 25 ends at the distal end 29, and the handpiece 23 axis continues through the proboscis 27 in a substantially straight line to a second reference plane 45, which plane 45 is in close proximately to the proboscis distal end 41, at which plane 45 said channels 37 and 39, and the proboscis 27 are angled downward about thirty degrees (30°), for communicating directly with an operating site at which a dental bur extending from the removable turbine housing 21 may be directed. Those skilled in the art will recognize that the handpiece 23 may also be

formed in various other configurations for meeting the tactile considerations of a wide variety of operators, in accordance with the present invention.

As illustrated in Fig.s 4 A - F, the preferred cross section shape of the handle 25 changes from substantially circular at the handle proximate end 31 to substantially cardioid as the distance between a cross section and the handle proximate end 31 increases and the distance between said cross section and the handle distal end 29 decreases. The cross section area of the proboscis 27 also decreases as the distance between a cross section and the handle distal end 29 increases and the distance between said cross section and the proboscis distal end 41 decreases. This change in cross section shape and area is further manifested along that portion of the removable turbine housing 21 which connects to the handle distal end 29 and acts as an extension of the handle 25 with regard to the area that is manipulatable by an operator when the components of the assembly 10 are in operable position in one of the operator's hands. This preferred ergonomic shape of the assembly 10 provides an operator a significantly higher degree of tactile angular information conceming the angular positioning of a dental bur extending from the turbine housing 21 than that which is provided in dental handpieces of the prior art, which dental handpieces tend to be substantially circular in cross section. It is further believed that the ease with which the dental handpiece ^' with removable turbine housing 10 is manipulated may offer significant relief to those operators afflicted with carpal tunnel syndrome or arthritis. Those skilled in the art will recognize, however, that the instant invention may be formed having a more traditional cross section shape for those operators desiring a more traditional tactile sensation with their dental handpiece.

Referring again to the cross section views A - F of Fig. 4, the reader should observe that the cross section shapes of the channels 33 - 39 also change as the distance between a cross section and the handle proximate end 31 increases and the distance between a cross section and the proboscis distal end 41 decreases, for providing in each of said channels 33 - 39 a substantially consistent cross section area. The outer surfaces of the handle 25 and the removable turbine housing 21 may further include annular ridges (not shown) for providing a non-slip gripping surface. The handle proximate end 31 further includes means for mounting thereto a standard industry pneumatic supply connector, such as a MIDWEST five-hole connector, a rotatable swivel coupler, or the like, for allowing communication between the channels 33 - 39 and external conduits in communication with various resources, such as sources of turbine impelling fluid, air, water and light, or the like. Said mounting means is a proximate cavity 47 formed in the handle proximate end 31.

With regard to the fiber-optic channel 39, it is preferred that a fiber-optic bundle 49

which is insertable therein, an associated fiber-optic portion of said supply connector such as that which is known, and an external fiber-optic conduit such as that which is known and which is in communication with a light source such as that which is known, comprise coherent fiber-optic image transmission means such as that which is known, for allowing light reflected by an operating site to be communicated through said bundle 49, said supply connector and said external fiber-optic conduit for use by video imaging means such as that which is known.

That there are so few movable parts in the handpiece 23, allows said handpiece 23 to be manufactured via inexpensive manufacturing methods, and thereby be made available to the consuming public at a cost which is substantially less than that of dental handpieces of the prior art. In the preferred embodiment, the handpiece 23 is manufactured of stainless steel via inexpensive casting and post-cast polishing means, although those skilled in the art will recognize other materials and methods of manufacture which may be used within the scope of the present invention, such as the cast forming of other metals, the form-cutting of metals, the die cutting of other metals, or the injection molding of metals or various other materials such as plastic-like materials, it will also be observed that methods of manufacture which are in current use pertaining to other dental handpieces, may also be employed in producing the handpiece of the instant invention. Such current methods include forming the handpiece out of a tube which may then be shaped in accordance with the present invention, with a plurality of smaller diameter tubes being inserted therein for providing the various channels for turbine impelling fluid, cooling water/misting air, and fiber-optic means. The handle can then be capped off at each of the distal and proximate ends via means which are known, leaving the cooling water/misting air and fiber-optic conduits free to extend through the removable turbine housing, for communicating directly with a dental operating site.

Fig.'s 5 - 12 illustrate various characteristics of a preferred embodiment of the removable turbine housing 21 according to the instant invention, which housing 21 comprises a cup shaped turbine chamber 51 having a substantially cylindrical outer side wall 53, an open cartridge-insertion upper end 55 and a semi-open bur-side lower end 57, which lower end 57 includes a downward oriented central aperture 59 through which a bur 61 (Fig. 1) may be extended. The turbine chamber 51 further includes a peripheral lower shelf 63 near the central aperture 59 for holding a turbine assembly (not shown) thereon; and still further includes a peripheral upper shelf 65 near the upper end 55 for holding a lid or cover (not shown) thereon, and thereby securing a turbine inside the chamber 51. A peripheral upper flange 67 may be optionally provided between the upper shelf 65 and the upper end 55, for securing a

portion of said lid between the upper shelf 65 and said upper flange 67. Those skilled in the art will recognize still other configurations in which the turbine chamber of the instant invention may be formed for cooperating with, or securing, various turbines which may be mountable within said chamber 51 , each of which other configurations are included within the scope of the instant invention. The removable turbine housing 21 further includes an elongate handle engaging member 69 having a distal end 71 which is affixed to the wall 49 of the turbine chamber 47, and a proximate end 73. The engaging member 69 further includes a plurality of elongate engaging member channels extending longitudinally therethrough, two of which engaging member channels include a turbine impelling fluid intake channel 75 and a turbine impelling fluid exhaust channel 77 for communicating between the turbine chamber 51 and corresponding channels of the handle 25. Another of the engaging member 69 channels is an extension arm engaging glove 79 into which the extension arm 27 of the handle 25 may be inserted for placing the removable turbine housing 21 in operable position on the handpiece 23. In the assembly 10, the engaging glove 79 is positioned within the engaging member 69 between the lower outer surface of said engaging member 69 and the intake and exhaust channels 75 and 77, and is further substantially parallel to said channels 75 and 77. Said engaging glove 79 further has an open proximate end 81 into which the handle extension arm 27 may be inserted; and a partially open distal end 83 including a misting/lighting aperture 85 located between the axis of the engaging glove 79 distal end 83 and the turbine chamber 51 lower end 57, through which aperture 85 channels 37 and 39 of the proboscis 27 may communicate directly with an operating site toward which a dental bur 61 extending from the removable turbine housing 21 may be directed. The pair of engaging member 69 fluid intake and exhaust channels 75 and 77, respectively, extend longitudinally between the turbine chamber 51 and the engaging member proximate end 73, whereat they are in communication with corresponding handle intake and exhaust channels 33 and 35, respectively, when the engaging member 69 is mounted in operable position on the handpiece 23. Referring now to Fig.'s 6 and 10 - 12, it will be observed that a significant difference exists between the cross section areas of the preferred embodiments of the engaging member 69 intake and exhaust channels 75 and 77, respectively. Whereas the cross section area of the exhaust channel 77 is substantially consistent throughout the length of said channel 77, the cross section area of the intake channel 75 decreases as the distance between a cross section and the engaging member 69 proximate end 73 increases and the distance between said cross section and the

engaging member 69 distal end 71 decreases. The purpose of such decreasing in cross section area of the intake channel 75 is two-fold: 1) to provide means for increasing the kinetic energy of a column of fluid being directed through said intake channel 75, and thereby increasing the velocity of said fluid as it exits the channel 75 and enters the turbine chamber 51 ; and 2) to provide a fluid focusing means whereby fluid which exits the channel 75 into the chamber 51 will impel each vane of a turbine mounted within the chamber 51 at a selected point of impact.

It will be observed further, that the exhaust channel 77 has a cross section shape and area which is substantially circular throughout, except that there is provided between the turbine housing 51 and the interior periphery of the channel 77 (with respect to the exterior of the engaging member 69) a fluid turbulence dampening flange 87, for dampening fluid turbulence which may exist between the housing 51 and the exhaust channel 77 when a turbine is operating within the chamber 51. Said flange 87 extends outwardly from the interior periphery (with respect to the exterior of the engaging member 69) of the channel 77, toward the nearest exterior surface of the engaging member 69. As fluid which is provided through the intake channel 75 for impelling a turbine within the chamber 51 moves about the periphery of the chamber 51 and comes into contact with the flange 87, it is moved efficiently into the exhaust channel 77. As each vane of said turbine passes the flange 87, there is a slicing effect that conveys the turbine impelling fluid away from said turbine and out of the chamber 51. Also it has been found that use of the flange 87 provides a turbine housing of the instant invention which is significantly quieter during operation of a turbine mounted therein, than such turbine housings of the prior art.

It is preferred that the removable turbine housing 27 is formed of a semi-rigid plastic material via injection molding for economic mass production, although those skilled in the art will recognize other materials, including metals, and methods of manufacture which will be just as suitable for the purposes of the instant invention. For purposes which are disclosed in the ensuing description, it is preferred that the material of which the turbine housing 21 is formed also has a modulus of elasticity which is sufficient for providing the semi-rigid elasticity that is required for providing the unique suspension system of the instant invention, which system is described further herein.

Still further included in the dental assembly 10 is means for securing the removable turbine housing 21 to the handpiece 23. Said securing means includes at least a rigid latch 89 affixed to the lower outer surface of the proboscis 27 (Fig.'s

4, 5 and 12), near the proboscis distal end 41. Said rigid latch 89 works in

cooperation with a movable latch 91 formed in the removable turbine housing 21 , and a unique tensioned suspension system of the removable housing 21 which is described further herein. As the removable housing 21 is placed into operable position on the handpiece 23, the movable latch 91 is slidably moved over the rigid latch 89 until such point at which the movable latch 91 has passed the rigid latch 89 and snaps into securing cooperation with the rigid latch 89. While the movable latch

91 is in such securing cooperation with the rigid latch 89, the turbine housing 21 cannot be slidably removed from its engagement with the handle 25 and extension arm 27. Those skilled in the art will recognize that such securing means can be formed in other configurations and located elsewhere on the handpiece 23 according to the instant invention. In such embodiments of the instant invention in which the movable latch is located on the removable turbine housing, it is preferred that the movable latch have an arc of movement which is slightly less than that which is required for removing the movable latch from cooperation with the rigid latch, for allowing the movable latch to be broken simultaneously with such removing. This will insure that each removable turbine housing sees only limited use, and will further encourage operators of the instant invention to dispose of such removable turbine housings after each use, and thereby insure aseptic conditions.

In order to overcome various problems associated with dental hand pieces having removable turbine housings of the prior art, which problems relate to the connection between a removable turbine housing made of a plastic type material and a handpiece made of metal, a unique tensioned suspension system has been provided in the illustrated embodiments of the dental handpiece with removable turbine housing assemblies of the instant invention. Such suspension system comprises means whereby a distally oriented pressure is exerted by the handpiece 23 against various suspension points of the removable turbine housing 21 , responsive to a proximately oriented pressure applied against the turbine chamber 51 of the removable turbine housing 21 by an operator of the invention when mounting said housing 21 onto the dental handpiece 23. Cooperation between the movable and rigid latch means of the prior discussion allows the removable turbine housing 21 to overcome such distally oriented pressure and stay mounted to the handpiece 23.

The first part of said suspension system comprises a pair of channel extension and compression nipples 93 (Fig.'s 2 and 6 - 9) which extend proximately from the proximate end 73 of the engaging member 69, for communicating between the intake/exhaust channels 75 and 77 of the engaging member 69 and the intake and exhaust channels 33 and 35, respectively, of the handle 25. Each of said

compression nipples 93 are coaxial with the corresponding intake or exhaust channel

75 or 77 of the engaging member 69, and have an intemal cross section area which is substantially equivalent to the intemal cross section area of the proximate end of said corresponding channel 75 or 77. The extemal cross section area of each compression nipple 93 is tapered, decreasing as the distance between the proximate end 73 of the engaging member 69 and said cross section increases. A corresponding compression nipple female mating cavity 95 is provided at the distal end 29 of each of the handle 25 intake and exhaust channels 33 and 35, respectively, for communicating with one of the compression nipples 93. The cross section shape of each mating cavity 95 is tapered substantially similar to the extemal cross section shape of the corresponding compression nipple 93. However, it is preferred that the smallest cross section diameter of each mating cavity 95 is less than the similar smallest extemal cross section diameter of the corresponding compression nipple 93; and that the length of each mating cavity 95 is greater than the length of the corresponding compression nipple 93, with the cross section diameter of the distal portion of each mating cavity 95 being slightly smaller than the largest external cross section diameter of the corresponding compression nipple 93. The difference in size and shape between the compression nipples 93 and the corresponding mating cavities 95 allow each compression nipple 93 to be insertable into the corresponding mating cavity 95 in such a manner as to provide a fluid-tight seal between each compression nipple 93 and corresponding mating cavity 95. Also, as the compression nipples 93 are inserted into the mating cavities 95, a distally oriented force is applied against each compression nipple 93 by the corresponding mating cavity 95, for stabilizing both angular and radial alignment of the removable turbine housing 21 onto the handpiece 23 as part of the tensioned suspension system of the dental handpiece 10.

Referring now to Fig. 12, it will be observed that the shape and size of the proboscis 27 and the engaging glove 79 are substantially similar, with the main exception being that the proboscis 27 is slightly longer than the glove 79, for providing various locations where distally oriented pressure is applied by the handpiece 23 against the removable turbine housing 21 when the turbine housing 21 is mounted onto the handpiece 23 in operable position. It will be further observed that each of the mating cavities 95 exert a distally oriented pressure against the compression nipples 93; and that the upper portions of the proboscis distal end 41 also exert an upward and distally oriented pressure against corresponding areas of the engaging glove 79 with which said proboscis 27 upper portions are engaged. It will be still further observed that a lower region 97 of the proboscis 27 also exerts a

downward and distally oriented pressure against areas of the engaging glove 79 which correspond to said proboscis 27 lower region 97. Also, referring back to the cross section views A and B of Fig. 3, it will be observed that the preferred embodiment of the proboscis 27 includes substantially three outer surface regions: two substantially congruent elongate upper regions 99 which are substantially planar; and the lower region 97; each of which regions terminate at its distal end for forming the distal end 41 of the proboscis 27. Each of the upper regions 99 meet along corresponding interior elongate edges at a convex angle for forming a proboscis spine 102. Also, the lower region 97 joins each upper region 99 along corresponding elongate edges. A cross section of the lower region 97 is substantially semi-cardioid in shape. Although the engaging glove 67 is shaped and tapered substantially similar to the extemal shape of the proboscis 27, it is preferred that the largest cross section diameter of said engaging glove 67 is slightly less than the similar largest external cross section diameter of the proboscis 27; and that the length of the proboscis 27 is slightly greater than the length of the engaging glove 67, with the cross section diameter of the distal portion of the engaging glove 67 being slightly smaller than the extemal cross section diameter of the proboscis 27. The difference in size and shape between the engaging glove 67 and the proboscis 27 allows the proboscis 27 to be insertable into the engaging glove 67 in such a manner as to provide a tight engaging seal between said proboscis 27 and the engaging glove 67. At this juncture, the reader should note that there are several key areas where the handpiece 23 is exerting distally oriented pressure against the turbine housing 21 , which pressure should be sufficient for forcing the housing 21 away from the handpiece 23, except for the earlier noted provision of means whereby the removable turbine housing 21 can overcome such distally oriented pressure and stay mounted to the handpiece 23. Such overcoming means is designed for working in conjunction with the earlier noted means of the handpiece 21 for securing to itself the removable turbine housing 23. Said securing means of the assembly 10 is the rigid latch 89 which is affixed to the lower region 97 of the proboscis 27. Said rigid latch 89 is designed for engaging the corresponding movable latch 91 , formed in a portion of the lower wall of the engaging glove 79 which corresponds to the proboscis 27 lower region 97, between the rigid latch 89 and the distal end 29 of the handle 25, when the turbine housing 21 is in operable position mounted to the handpiece 23. In the assembly 10, said movable latch 91 extends from a proximate side of a substantially rectangular elongate latch aperture 104 positioned in the lower wall of the engaging glove 79, for engaging the rigid latch 89 when the turbine housing 21 is placed in operable position mounted to the handpiece 23. The movable latch 91 is

substantially rectangular in shape and extends distally from said proximate side of the elongate latch aperture 104 to which it is affixed, toward a distal end of said latch aperture. A gap 106 exists between the distal end of the movable latch 91 and the distal end of the latch aperture 104, through which gap 106 the rigid latch 89 extends when the movable latch 91 is in securing cooperation with said rigid latch 89. As the movable latch 91 of the housing 21 engages the rigid latch 89 of the proboscis 27, the distally oriented pressure which is being applied against the turbine housing 21 by the handpiece 23 is held in check, keeping the removable turbine housing 21 in a secure position on the proboscis 27. It is preferred that the distance between the distal end of the movable latch 91 and the engaging member proximate end 73 is slightly greater than the distance between the proximate end of the rigid latch 89 and the handle distal end 29. This will result in the movable latch 91 being placed into longitudinal compression when said movable latch 91 is securingly engaged by the rigid latch 89; and thereby, cause the movable latch 91 to exert a dynamic proximately oriented force against the proximate end of the latch aperture 104. Such dynamic proximately oriented force cooperates with the distally oriented forces which are exerted by the cavities 95 and the proboscis 27 against the housing 21 , for creating a dynamic engaging seal between the housing 21 and the handpiece 23, which seal is not degraded by extensive handling of the joined handpiece 23 and housing 21. A latch aperture 108 is still further provided through the distal end of the movable latch 91 , into which aperture 108 a sharp instrument may be inserted for pulling the distal end of the latch 91 away from the proboscis 27, and thereby disengaging the movable latch 91 from the rigid latch 89 of the removable turbine housing 21 for removing said turbine housing 21 from the handpiece 23. The uniquely snug fit between the removable turbine housing 21 and the handpiece 23 of the instant invention which is provided via the tensioned suspension system, further provides an operator with a tactile sensitivity which is significantly greater than that which has been available through dental handpieces of the prior art that incorporate removable turbine housings. Such tactile sensitivity can be enhanced even further by decreasing the size of the gap between the proboscis distal end 41 and a turbine assembly placed inside the chamber 51. It has been found that the instant invention can be formed quite readily with this gap being less than 1/27 of an inch in breadth.

Referring now to Fig.'s 2, 7, 9, and 13 - 22, it will be observed that a unique pneumatic turbine assembly 110 is provided for mounting in the turbine chamber 51 of the turbine housing 21. Said turbine assembly 110 comprises a new and improved high speed pneumatic turbine 112 including means for dividing and rechanneling a

column of fluid impelled upon it from the fluid intake channel 75 of the turbine housing

21 , whereby said fluid may be moved efficiently about the intemal periphery of the turbine chamber 51 and into the fluid exhaust channel 77 which is in communication with the turbine chamber 51. The turbine 112 may further include the bur 61 manufactured as an integral part of the turbine 112, or said turbine 112 may include means whereby a removable bur (not shown) may be inserted into the turbine 112.

Referring to the cross section view of the turbine 112 (Fig. 14), it will be observed that the turbine 112 comprises a plurality of substantially congruent rotor vanes 114 formed in an annular array about, and extending radially from, a turbine rotor 116. Each vane 95 comprises a central ridge 118 defining its outermost periphery, a driving face 120 and a trailing face 122. Each driving and trailing face,

120 and 122 respectively, further comprises an upper half (120U or 122U) and a lower half (120L or 122L), with respect to the bur 61 , each of which halves are substantially mirror images of the other. The plurality of vane central ridges 118 are connected in an annular array and lie in substantially the same plane. Each vane central ridge 118 is further formed in a wave-like pattem having a crest 124 and a trough 126 (Fig. 13). In the preferred embodiment, both the crest 124 and the trough 126 of each wave form of the central ridge 118 lie in substantially the same radial plane of the turbine 112; and the remaining portion of the wave-form is in the pattem of a gentle slope increasing in radial distance from the rotor 116 as the distance between any point along the central ridge 118 and the trough 126 increases, which is a form substantially similar to that of a breaking wave of water.

A radial plane which includes the crest 124 and trough 126 of each vane 114, and which plane is further perpendicular to the vane central ridge 118, extending from the rotor 116 to the crest 124, substantially defines the driving face 120 of each vane 114. As the distance between each similar cross sectional radial plane in the trailing face of a vane 114, and the corresponding vane trough 126 increases, and the distance between said plane and the next crest 124 decreases, the angle X formed in the plane between the corresponding upper and lower half vane 114 surfaces, 128 and 130 respectively, becomes increasingly convex. As the distance between each similar radial plane in the driving face 120 of a vane 114 and the vane trough 126 decreases, and the distance between said plane and the prior crest 124 increases, the angle Y formed in the plane by the corresponding upper and lower half vane surfaces, 128 and 130 respectively, becomes increasingly concave. In other words, the central ridge 118 angle X or Y formed in a radial plane between the corresponding upper and lower half vane 114 surfaces, 128 and 130 respectively, becomes increasingly greater as the radial distance between said angle and the rotor

116 increases; and, said angle X or Y becomes increasingly smaller as the radial distance between said angle and the rotor 116 decreases.

This preferred design for the vane driving and trailing faces, 120 and 122 respectively, overcomes a significant problem of inefficiency in the prior art of single medium turbines having an axis perpendicular to the direction from which an impelling medium is impacting each turbine vane. In such turbines of the prior art, the impelling medium is not readily expelled away from the turbine vane which it impacts, and thus creates a significant parasitic drag upon the turbine elements by its remaining near the impact site in a highly turbulent state and its impelling the incoming medium jet before said incoming jet can strike the subsequent turbine vane. The turbine 112 of the instant invention differs from such traditionally designed impulse turbines in that the incoming jet stream of the impelling medium is diverted away from a selected high point of impact with respect to the turbine rotor 116, and channeled toward the rotor 116 by the driving face 120. Upon initial impact with the driving face 120, said jet stream becomes simultaneously split into two components while beginning to change its direction of flow from a tangential direction into an axial direction, resulting in the efficient expulsion of the spent jet stream from the driving face 120 and trailing face 122 areas. The incoming jet stream is intercepted by the curved vane tip of the driving face 120, which redirects the stream from a tangential path to a radial path, inward on the vane 114 toward the rotor 116. The central ridge 118 divides the incoming jet stream into two smaller component streams. Each component stream is then redirected inward radially, and outward axially, along the concave curvature of the driving face 120, for producing a resultant force against the driving face 120 until the jet stream reaches the rotor 116 area, where it is subsequently expelled outward from the turbine 112 as spent jet medium. Therefore, the jet stream begins tangentially, is redirected radially and axially, and then redirected further axially for efficient expulsion out the exhaust channel 77. These stream redirections are engineered to produce a minimum of turbulent flow, and thereby maximize the efficiency of transforming the kinetic energy of the impelling jet stream into mechanical rotation of the turbine 112. Also, the central ridge 118 of each vane 114, in conjunction with the selected contour of each vane 114 surface, serves the purpose of reducing drag by cutting through any ambient fluid and expelling said fluid in an axial direction. The radial and axial components of motion which are imparted to each of the component jet streams by the contour of the driving face 120, combine to produce a swirl or vortic flow of the jet medium at a point away from the turbine 112 driving and trailing face areas, 120 and 122 respectively. The vortic shape of each component of the redirected jet medium confines most of the

high energy turbulence resulting from the initial impact of the jet stream with the driving face 120, into a contained space away from the moving turbine components, until the spent stream can exit the chamber 51 through the exhaust channel 77.

The efficiency of the instant turbine design is much less dependent upon a contrasting density between the fluid jet and that of the ambient medium. The incoming jet stream impacts the driving faces 120 of the vanes 114 in a direction which is tangential to the rotation of the turbine 112. Said stream is immediately intercepted by the driving face 120 surface, and efficiently redirected away from the driving face 120 toward the rotor 116. Simultaneously with said redirecting, the stream is split into two component streams, each of which is further channeled in an axial direction away from the turbine 1 12 plane of rotation, in a direction which is opposite that of the corresponding component stream. That is, the impelling fluid stream gradually transitions from a tangential direction of flow into a radial orientation, and then into an axial direction. The radial and axial components of the redirected jet stream components form a vortex which tends to follow the rotation of the rotor 116 about the periphery of the chamber 51 until they reach the exhaust channel 77 and exit the chamber 51. With the turbine of the instant invention, all resultant forces from the transition of the jet stream's tangential direction to its final axial direction act upon the driving face 120 of the vane 114 in the relative absence of destructive turbulence, resulting in improved torque, increased rotational velocity and optimized mechanical efficiency. Simply stated, a column of impelling fluid is divided by the turbine of the instant invention into a plurality of vortic fluid masses, which masses are then moved out of the path of following incoming medium and spun efficiently about the periphery of the chamber 51 for being expelled from said chamber 51 into the exhaust channel 77. It is preferred that the turbine 112 and rotor 116 be formed as an integral unit of a semi-rigid plastic material which is light-weight and injection moldable, so that the bur 61 may be joined economically into the turbine assembly 110 as part of the same injection molding process. However, those skilled in the art will recognize other materials and methods of manufacture which may be just as suitable for the purposes of the instant invention.

Although the turbine of the instant invention has been designed primarily for use in a dental handpiece, those skilled in the art will recognize that it has further uses which are quite broad. For instance, commercial or passenger jet airplanes could employ a version of the instant turbine affixed to the sides of their landing gear wheels for the purpose of employing the rushing airstream for producing spin of the wheels prior to touchdown. This spin can significantly reduce wear and tear on the

landing gear tires. Since airplane tires are quite expensive and incur the great majority of their wear at landing speed touchdown, such an improvement in the design of the adjoining landing gear wheels can produce significant cost savings. Other uses for the turbine of the instant invention include the many diverse applications for fluid or pneumatic turbines which are already, or which will be, in use throughout the world.

Referring to Fig.'s 15 - 22, the dental handpiece 10 or turbine assembly 110 may further comprise a pair of self-aligning angular contact duplex bearing groups, or bearing races, which are designed for overcoming dimensional variances between the various components of the disposable head assembly, which variances may result from the high speed mass production of such components. Said pair includes: a semi-rigid upper bearing race 132 having an enlarged and semi-spherical (in cross section) multi-track bearing housing 134 which is circumscribed by a circular seating plane 136 which is of a diameter substantially similar to the turbine chamber 51 ; and a semi-flexible lower bearing race 138 having a single track housing 140 which is semi-toroidal (in cross section) and which is circumscribed by a seating plane 142, which plane 142 has a diameter smaller than that of the chamber 51 and further having a plurality of spring arms 144 extending angularly therefrom. Each of the spring arms 144 extends radially from the plane 142 a distance W and then forms a substantially right angle for circumscribing a portion of the seating plane 142. Each arm 120 is further crimped at a location 146 between the point at which it forms said right angle and the free end 148 of the arm 120, for bending the arm 120 in the same angular direction from the seating plane 142 as that in which the housing 140 extends away from the plane 142. Said crimp at location 146 is made in a canted fashion, for increasing the angle in which the arm 120 extends from the seating plane 142, such that a distance V between the free arm end 148 and the periphery of the seating plane 142 is greater than the distance W. The greatest diameter of the lower bearing race 138 is slightly greater than the diameter of the chamber 51.

Those skilled in the art are aware that conventional angular contact duplex pairs require extreme accuracy in the diameters, concentricity, and planar parallelism of the mounting means thereof. This degree of accuracy is unattainable in inexpensive molded parts. Prior art depicts machined metal members as the mounting components for these angular contact bearings, and further, must include means for creating the precise bearing preload which is required by such duplex angular contact bearings. These are expensive manufacturing requirements to accomplish, and, therefore, are not conducive to use in disposable, throw-away

products. The angular contact bearing duplex pair of the instant invention was invented in order to make possible a suitably inexpensive disposable head assembly.

Refemng to Fig.'s 21 and 22, it will be observed that the turbine assembly 110 is suspended in the embodiment of the bearing assembly of the instant comprising the upper bearing race 132, lower bearing race 138 and bearings 150. Self-alignment of the turbine assembly 110 is accomplished via mechanical communication between the bearing races 112 and 116 through the turbine assembly 110. The semi-spherical shape of the housing 134 cross section shape of the upper bearing race 132 has a diameter which is greater than that of the bearings 150, which allows the bearings 150 to set in a variety of planes, as illustrated in their setting in a plane P - P in Fig. 21 and their setting in a different plane R - R in Fig. 22. Unlike the upper bearing race 132, the cross section shape of the housing 140 of the lower bearing race 138 is substantially toroidal, not allowing any angular movement of the bearings out of a rotational plane between said housing 116 and an inner bearing race 152 which is circumscribed angularly about the turbine rotor 116. However, the appropriate compensation for the different setting of the upper bearings into various rotational planes is achieved via flexing of the spring arms 144. Such flexing allows the bearings 150 of the lower bearing race 138 to remain in their rotational plane S about the rotor 116, even though the rotor 116 has changed angular position resultant to the resetting of the upper bearings 150 into the plane R - R. After considering the Fig.'s 21 and 22, those skilled in the art will recognize that the spring arms 144 members which serve the purposes of (1 ) preload, (2) allowance of raceway tilt, and (3) positions the race radially with respect to the turbine chamber. Both inner raceways 128 are formed on the rotor 116 and are of conventional toroidal design. The advantages of this self-aligning angular contact duplex bearing pair are that they: (1) are inexpensive to manufacture; (2) have wide adaptability; (3) are tolerant of manufacturing variances; (4) have reduced part count; and (5) lends itself well to automatic assembly.

The inventor has given a non-limiting description of several embodiments of the present invention, to which many changes may be made without deviating from the spirit of the inherent inventive concept. While this invention has been described with reference to such illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the various embodiments as well as other embodiments of this invention will be apparent to a person skilled in the art upon reference to this description. It is therefore contemplated that the appended claims cover any such modifications and/or embodiments that fall within the true scope of the present invention.