Patent Application
20150132713
The present invention relates to a dental handpiece having a turbine head containing high-speed turbine for rotating a dental workpiece drill burr. More particularly, the present invention relates to dental handpiece having a turbine head with a vortex-washer-driven particulate discharge.
During a dental procedure involving the application of a rotating dental workpiece to a dental worksite, particulate matter from the worksite may be introduced in the air reducing or obscuring visibility of the worksite. This problem is commonly mitigated by the presence of a suction device proximal to the worksite. The suction device, itself, may also block visibility of the worksite.
Accordingly, there is a need in the art for a dental handpiece having a turbine head that is able to remove small particulate entrained in the air proximal to the worksite.
Briefly stated, one embodiment of the present invention is directed to a dental handpiece for rotating a dental workpiece has a housing having a generally cylindrical housing side wall terminating at a first end having a housing end wall. A gas-driven handpiece motor assembly includes a rotor shaft having an axis of rotation substantially coincident with a central longitudinal axis of the housing. A chuck assembly is secured to the rotor shaft. The chuck assembly has a burr tube configured to releasably hold the dental workpiece. A portion of the burr tube passes through the housing end wall forming an opening concentric with and spaced from the burr tube. A bearing assembly radially supports the motor assembly. The bearing assembly has a first hearing disposed toward and supported by the first end of the housing and includes an inner race fixed to the burr tube and an outer race having an inner wall facing radially inwardly toward the axis of the rotor shaft. A first flange is connected to a first end of the inner wall of the outer race and extends radially inwardly of the inner wall in a plane substantially perpendicular to the axis of the rotor shaft. The first flange has a lateral face disposed toward the housing end wall. A cavity is formed by the first lateral face of the first flange, the first end of the housing and the housing end wall. The cavity is in fluid communication with the opening in the housing end wall and a vent in the first end of the housing. A vortex washer is disposed in the cavity and fixed to the burr tube.
The foregoing summary, as well as the following detailed description of preferred embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, the drawings show embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.
In the drawings:
Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
As used in the description of the invention and the appended claims, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The words “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The words “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
The words “right,” “left,” “lower” and “upper” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the dental handpiece, and designated parts thereof. The terminology includes the words noted above, derivatives thereof and words of similar import.
Although the words first, second, etc., are used herein to describe various elements, these elements should not be limited by these words. These words are only used to distinguish one element from another. For example, a first bearing could be termed a second bearing, and, similarly, a second bearing could be termed a first bearing, without departing from the scope of the present invention.
The following description is directed towards various embodiments of a dental handpiece in accordance with the present invention.
Referring to the drawings in detail, where like numerals indicate like elements throughout, there is shown in
The dental handpiece 1 includes an elongated tubular housing 2 which terminates at a first end 2a in a turbine head 10 attached at an angle to the tubular housing 2. A dental workpiece 3, such as the drill burr shown in
Referring to
A gas-driven turbine motor assembly 20 is disposed in the turbine head housing 12.
The turbine motor assembly 20 has a turbine rotor shaft 22 supporting a plurality of turbine vanes 24. The turbine rotor shaft 22 has an axis of rotation substantially coincident with the central longitudinal axis “A” of the turbine head 12. The turbine motor assembly 20 further includes a chuck assembly 26 and a bearing assembly 28. The chuck assembly 26 has a burr tube 30 secured to the turbine rotor for rotation wherewith. The burr tube 30 is configured to releasably hold the dental workpiece 3. A portion of the burr tube 30 passes through the housing end wall 18 and forms an opening 32 concentric with and spaced from the burr tube 30. The bearing assembly 28 supports the burr tube and has a first bearing 34 disposed toward and supported by the first end 12a of the turbine head housing 12 and a second bearing 36 disposed toward the turbine head endcap 14 and supported by a portion of the housing side wall 16 proximal to the turbine head endcap 14.
Referring to
The first bearing assembly 34 has an annular inner race 38 fixed to the burr tube 30. and an annular outer race 40 . A set of bearing elements 42 are confined between and in frictional engagement with the inner and outer races 38, 40. The outer race 40 has an inner wall 44 facing radially inwardly toward the axis of the rotor shaft 22. A first flange 46 is connected to a first end 44a of the inner wall 44 of the outer race 40. The first flange 46 extends radially inwardly from the inner wall 44 in a plane substantially perpendicular to the axis of the rotor shaft. The first flange 46 has a lateral face 48 disposed toward the housing end wall 18.
The outer race 40 has an outer wall 50 facing radially outwardly of the axis of rotation of the rotor shaft 22. A second flange 52 is connected to a first end 50a of the outer wall 50 of the outer race 40. The second flange 52 extends radially outwardly from the outer wall 40 in a plane substantially perpendicular to the axis of the rotor shaft 22. The second flange 52 has a first lateral face 54 disposed toward the first end 16a of the housing side wall 16. A substantially flat washer 56 couples the first lateral face 54 of the second flange 53 to a portion of the housing sidewall 16. A snap ring 58 in a circumferential groove 60 proximal to a second end 50b of the outer wall 40 couples the outer race 40 to a portion of the housing sidewall 16. A pair of rings 62 fabricated from a resilient mater is disposed between the substantially flat washer 56 and the snap ring 58 and provide a compressive fit between the outer wall 40 and a portion of the housing sidewall 16.
A cavity 64 is formed by the first lateral face 48 of the first flange 46, the first end 16a of the housing sidewall 16 and the housing end wall 18. The cavity 64 is in fluid communication with the opening 32 in the housing end wall 18 and a vent 66 to atmosphere in the first end 16a of the housing 16. In some embodiments, the first end 16a of the housing 16 has a plurality of spaced apart vents 66 in fluid communication with the cavity 64.
A vortex washer 68 is disposed in the cavity 64 and fixed to the burr tube 30. Preferably, the vortex washer 68 is fixed to the burr tube 30 by a press or compression fit. The vortex washer 68 extends radially outwardly of the burr tube 30 in a plane substantially perpendicular to the axis “A” of the turbine head “A”. Preferably, in some embodiments the vortex washer 68 adjoins the inner race 38. In other embodiments, the vortex washer 68 may be spaced from the inner race 38. Although in some embodiments, the vortex washer 68 may have a uniform thickness, in a preferred embodiment, the vortex washer 68 comprises an inner portion 68a extending outwardly a first radius R1 from the burr tube 30 and has a first thickness T1 and an outer portion 68b extending outwardly from the burr tube 30 a second radius R2 greater than the first radius R1 and has a second thickness T2 less than the first thickness T1. (See,
During use of the dental handpiece 1, when pressurized drive air is applied to the turbine motor assembly 20, the turbine vanes rotates causing the burr tube 30 with the vortex washer 68 fixed thereto to rotate in turn. As the vortex washer 68 rotates, the concentric opening 32 in the housing end wall 18 functions as an inlet port through which air outside the turbine head housing 12 proximal to the housing end wall 18 is drawn into the cavity 64 and forced by the rotation of the vortex washer 68 out of the cavity through the vent 66 which functions as an outlet port in the first end 16a of the housing sidewall 16a. Small particulate entrained in the air flow is therefore drawn from the dental work site into the cavity 64 and discharged through the air vent 66.
The foregoing detailed description of the invention has been disclosed with reference to specific embodiments. However, the disclosure is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Those skilled in the art will appreciate that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. Therefore, the disclosure is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.
