US 3055112 A
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Description (OCR text may contain errors)
Sept. 25, 1962 J. v. BORDEN 3,055,112
STABILIZED TURBINE FOR DENTAL HANDPIECE Filed July 28, 1959 INV E N TOR JOHN l. BORDEN BY jug awmwam ATTORNEYS United States Patent Ofilice 3,055,] 12 Patented Sept. 25, 1962 3,055,112 STABILIZED TURBINE FOR DENTAL HANDPIECE John V. Borden, Rauson, W. Va. Filed July 28, 1959, Ser. No. 830,102 Claims. (Cl. 32-27) This invention relates to dental handpieces and particularly to dental handpieces having an air turbine consisting of twin rows of rotor vanes on either side of a centrally disposed annular pressurized chamber. It is an object of this invention to so construct the rotor vanes whereby both axial and radial forces are administered to the turbine for a stabilizing effect.
A further objective of the invention is to provide structure to permit air to .act on all of the rotor blades at the same time, thereby permitting a smoother operation than those handpieces having the rotor blades sequentially hit by the air source. This structure also increases the torque potentiality of the handpiece.
A still further objective of the invention is to direct the pressurized air from the handle of the handpiece in both an axial and radial direction so that the capsule will be stabilized in the capsule housing.
It is another objective of this invention to provide directional stators about the annular space between the rows of vanes to confine and direct more accurately the pressurized air in the space between the vanes.
Further objectives and advantages of this invention will be apparent from the following description and claims wherein the construction, arrangement and cooperation of the several parts of the drive are set forth.
In the drawings:
FIG. 1 is an enlarged cross-sectional view of a handpiece; and
FIG. 2 is a partial view of a further embodiment of the invention wherein directional stators have been added.
FIG. 3 is a cross-section on a reduced scale taken on the line 3-3 of FIG. 1.
Referring now to FIG. 1, the numeral 10 designates a dental handpiece. The handpiece is comprised generally of a cylindrical capsule housing 12 and a handle 14. The cylindrical housing 12 is of a type adapted to re ceive a turbine capsule 16 therein.
The cylindrical housing 12 is comprised of tubular side wall 18, the removable bottom 20 which has shaftreceiving opening 22 centrally disposed therein, and the removable cap 21 which completes the housing. The bottom 20 is further characterized by having along its interior surface an annular bearing receiving step 24 defining by its rise 25 a space of slightly larger diameter than the outside diameter of the lower portion of the capsule 16.
The capsule 16 is circumferentially enclosed by a tubular member 26 adapted to fit snugly within the cylindrical housing 12. The member 26 is enclosed at its upper and lower ends by the slotted sleeves 27 and 29. Ball bearing units 28 and 30 are mounted on the sleeves 27 and 29 and are adapted to rotatably mount the shaft 32 and turbine 34. The sleeves have flanges 36 and 38 respectively to receive the bearing units. The bur shaft 41 is removably associated with the shaft 32 by any conventional means such as plastic liner 42. This method of removably aifixing the bur to the turbine and bearings can be accomplished by means known to the art, and such attaching means fall outside the scope of this invention.
The turbine 34 is comprised of an upper tier of vanes 36 and a lower tier of vanes 38. The tiers are disposed on either side of an annular air-receiving chamber 40. The vanes in the described embodiment are arc-shaped and are adapted to receive the air from chamber 40, as shown by the arrows in FIG. 1.
Disposed on either side of the turbine 34 and spaced slightly therefrom are the above-mentioned slotted sleeves 27 and 29. The sleeves are aflixed to member 26 about their peripheries and are so slotted that they will allow some part of the air expended from the vanes to escape through bearings 28 and 30, and a further fraction of the air to escape into the annular exhaust channels 52 and 54. These exhaust channels are,each in communication with the space between the steps 23' and 25 and the outer dimension of the capsule 26. The air which does not escape through the exhaust channel 54 will find its way into the atmosphere through the annular space defined by aperture 22 and the bur 41. The air not exhausted through channel 52 will find its Way through slotted sleeve 27, bearing 32 and out through a centrally disposed aperture 56 in the housing cap 21.
The speed and pressure of the air will isolate, to some extent, the capsule from the capsule housing at points near the bearings and thereby reduce much of the noise normally generated by handpieces of this nature.
A summary of the operation of the handpiece is as follows. The air which is utilized to operate the handpiece enters via the handle 14 by air delivery conduit 60. This conduit is aligned with an opening 62 in the capsule housing 12. The conduit 60 and the orifice 62 are, in turn, aligned with opening 64 in the capsule sleeve 26. This arrangement directs air pressure to be directed into annular space 40. The air in annular space 40 will rush axially and radially into the spaces between adjacent vanes of turbine 32. However, there will be a tendency for the pressure to equalize somewhat in space 40 before it changes its direction to strike the vanes. This distributed radial and axial flow will drive the turbine and maintain it in a balanced and modulated condition. Portions of the air escaping from the ends of the vanes opposite chamber 40 will escape into the space between slotted sleeves 27 and 29 and the raceways of the bearings. A portion will go to the space between the capsule and the capsule housing, and the remainder will be expended through the handpiece That portion of the air which escapes through the raceways of the bearings and the space between the capsule and the capsule housing will, through the space between the capsule aperture 22 and the bur shaft 41, or out through the centrally disposed aperture in the cap 21.
Referring to FIG. 2, there is shown structure which will aid in directing the air more efiiciently against the vanes 46 and 48. This structure includes the annular stators 70 and 72 fixedly positioned between the upper and lower tiers of vanes 46 and 48 and the annular space 50. The stators are comprised of angularly disposed vanes 74 and 76 leading from the space 50 to the turbine vanes. The stator is secured to the interior of tubular member 26 by the press-fit seals 78 and 80.
It should be understood that the scope of this invention should not be limited to the particular type dental handpiece disclosed. The pressurized space between tiers to distribute the force of the fluid driving the rotors would find uses in many applications. The slotted sleeves for seating the bearings and evenly disbursing the exhaust air likewise would find many applications other than in the embodiments described. Therefore, while I have, in a general manner, in the above description, disclosed what I deem to be practical and eificient embodiments of my invention, it should be well understood that I do not wish to be limited thereto, as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.
14 via exhaust ports 52 and 54.
in turn, be expended I claim:
1. In a dental handpiece, the combination including, a housing, a capsule removably received within said housing, said capsule comprising a self-contained highspeed, fluid-driven turbine, said capsule including a tubu lar shell having enclosed ends, a turbine rotor having a shaft to receive a drill bur, a pair of spaced anti-friction bearings attached to the respective ends of the tubular shell to support said rotor Within the capsule, said rotor having two sets of peripherally arranged vanes between said bearings and axially spaced from each other to provide a centrally disposed annular fluid chamber between said vanes, said capsule being provided with an inlet aperture in communication with said fluid chamber to admit fluid to drive said turbine and being also provided with an annular chamber at each end between the respective anti-friction bearings and said vanes to provide a path for a portion of the exhaust fluid to escape to the exterior of the capsule, said capsule being also provided with a discharge aperture adjacent each end thereof for the remainder of said fluid discharged from said vanes.
2. The invention as defined in claim 1, wherein two sets of axially spaced annularly arranged stator vanes are fixed within said tubular shell between said rotor vanes to direct fluid in said chamber axially toward said rotor vanes.
3. The mechanisms described in claim 1 wherein said rotor blades are arcuate in shape.
4. A turbine capsule for a dental handpiece comprising, in combination, a shaft for receiving a bur, two tiers of rotor blades mounted longitudinally along said shaft and defining an annular space therebetween, ball bearings mounted near both ends of said shaft to position said shaft concentrically within said capsule, the ends of said capsule comprising a pair of radially slotted sleeves hav ing seats therein for receiving said bearings, and a tubular member connecting the outer peripheries of each of said sleeves, said tubular member having an inlet aperture in communication with said annular space, said ball bearings being in fluid communication with the exterior of the capsule to permit the passage of a portion of the discharged air therethrough.
5. A turbine capsule for a dental handpiece comprising, in combination, two slotted end members, a tubular sleeve connecting said end members, a ball bearing unit mounted in each of said end members, a shaft for holding a bur supported at each end by said ball bearing units, two tiers of rotor blades mounted longitudinally along said shaft and defining a central annular space between the two tiers and also defining an annular space 50 between said ball bearings mounted near both ends of said shaft and the other ends of the respective tiers of blades, means to deliver fluid under pressure to said central annular space whereby when pressure throughout said space becomes distributed, said turbine will rotate, and exhaust means at both ends of said housing for exhausting the fluid expended in driving said turbine.
6. The invention described in claim 5 wherein said end members are slotted radially.
7. In air-driven dental drills, a-handpiece having a turbine housing at one end, rotor means for driving a dental bur contained within the housing, a pair of airlubricated anti-friction bearing means attached to opposite walls of the housing to rotatably support the ends of the rotor means, said rotor means including a hub and two axially spaced rows of axial-flow blades, the tips of the blades and the inner wall of the housing having complementary configurations of surfaces of revolution to confine the flow of motive air to axial directions from one side to the other of the blades, the mid-portion of the peripheral portion of the hub being radially spaced from the inner wall of the housing to provide a common annular air inlet for both said rows of blades, an annular portion of each end of the hub being spaced from the inner wall of the housing to provide a pair of annular outlets for air exhausted from the respective rows of blades, means to direct a single jet of air under pressure into said annular inlet in a direction tangential to the surface of the hub, means to exhaust air from said outlets, and means to exhaust a portion of said air to the atmosphere through said anti-friction bearing means.
8. The invention as defined in claim 7, wherein two axially spaced rows of guide vanes are fixed to the interior wall of the housing adjacent the inlet sides of the respective rotor blades.
9. The invention as defined in claim 7, wherein guide vanes are fixed to the interior of the housing adjacent the respective outlet sides of said respective rows of rotor blades.
.10. The invention as defined in claim 7, wherein the cross-sectional configuration of the rotor blades in a plane tangent to the periphery of the rotor means is crescent-shaped, the inlet and outlet angles being equal with respect to the plane normal to the axis of the rotor means.
Poole July 5, 1904 Warman Apr. 16, 1907