U.S. patent number 3,893,242 [Application Number 05/476,748] was granted by the patent office on 1975-07-08 for air driven dental handpiece.
This patent grant is currently assigned to Star Dental Manufacturing Co., Inc.. Invention is credited to Franklin W. Kerfoot, Jr., Nathaniel H. Lieb, Kurt Sotman, Richard A. Wallace.
United States Patent |
3,893,242 |
Lieb , et al. |
July 8, 1975 |
Air driven dental handpiece
Abstract
An air driven dental handpiece comprising a hollow handle and a
turbine housing mounted at one end thereof. The turbine housing
includes a rotor having rotor blades with arcuate recesses formed
therein. An air supply line is positioned within the handle and
includes two spaced tubes adapted to inject air under pressure into
the turbine housing and against the turbine blades. A fiber optical
system is mounted within the handle, which is adapted to direct
light from two separate sources adjacent the rotating bur mounted
in the handpiece. A novel wrench is provided for securing a bur in
the collet of the handpiece.
Inventors: |
Lieb; Nathaniel H. (Narberth,
PA), Kerfoot, Jr.; Franklin W. (Newtown Square, PA),
Wallace; Richard A. (Audubon, PA), Sotman; Kurt (Wynne,
PA) |
Assignee: |
Star Dental Manufacturing Co.,
Inc. (West Conshohocken, PA)
|
Family
ID: |
26912220 |
Appl.
No.: |
05/476,748 |
Filed: |
June 5, 1974 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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217745 |
Jan 14, 1972 |
|
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Current U.S.
Class: |
433/29; 433/127;
433/132 |
Current CPC
Class: |
A61C
1/141 (20130101); A61C 1/144 (20130101); A61C
1/145 (20130101); A61C 1/05 (20130101) |
Current International
Class: |
A61C
1/08 (20060101); A61C 1/05 (20060101); A61C
1/00 (20060101); A61C 1/14 (20060101); A61c
001/10 () |
Field of
Search: |
;32/27,26,DIG.1
;279/102,66 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Peshock; Robert
Assistant Examiner: Lever; J. Q.
Attorney, Agent or Firm: Caesar, Rivise, Bernstein &
Cohen
Parent Case Text
This application is a division of U.S. application Ser. No. 217,745
filed Jan. 14, 1972 and entitled Air Driven Dental Handpiece.
Claims
What is claimed as the invention is:
1. A dental handpiece comprising a hollow handle, a turbine housing
mounted perpendicularly on one end of said handle, said turbine
housing having an air turbine rotatably mounted therein, said air
turbine comprising a rotor shaft and a plurality of radially
extending blades mounted thereon, said rotor shaft extending
perpendicularly to said handle, and means within said handle for
delivering air to said blades for rotating the same, said air
delivering means comprising a pair of spaced tubes in said handle,
said tubes having ends thereof coplanar and lying in a plane that
is perpendicular to the axis of said rotor shaft, said ends
terminating at said turbine housing and being in fluid
communication with the interior of said turbine housing, said ends
having outlet ports adjacent said blades, with each of said tubes
adapted to supply air which impinges directly and radially against
said blades, a fiber optic lighting system within said handle, said
fiber optic lighting system comprising a plurality of light
transmitting fibers having an opaque sheathing thereover, said
light system having a terminus adjacent said turbine housing, said
terminus projecting from said handle and being adapted to direct
light passing through said fiber optic system to the area around a
dental bur which is secured in said housing, said rotor shaft being
rotatably mounted in said housing, said rotor shaft having a hollow
bore, a collet threadedly secured within said rotor shaft, said
collet having a plurality of jaws which are compressible by said
rotor shaft when said collet is threadedly advanced within said
rotor shaft, and said jaws expanding when said collet is retracted
in said rotor shaft, said rotor shaft having at least one axial
slot formed in the top thereof, and a wrench for advancing and
retracting said collet in said rotor shaft, said wrench comprising
a housing, said wrench housing being placed over said turbine
housing of said dental handpiece, a tube mounted in said wrench
housing, said tube being secured to said wrench housing, said
wrench housing having a cavity formed therein, means within said
cavity securing said wrench housing on said turbine housing, said
securing means comprising a spring, said spring being positioned
within a groove formed in the wall of said cavity, said tube having
a finger which is received in said slot of said rotor shaft, and a
shaft rotatably mounted within said tube, said tube shaft being
adapted to threadedly advance or retract said collet relative to
said rotor shaft.
Description
This invention relates to a dental handpiece, and more
particularly, to a novel air driven dental handpiece that includes
a novel turbine, a novel internal light system and a novel wrench
for securing a dental bur in the handpiece.
It is now common practice in the dental art to supply rotative
power to a dental handpiece through the use of an air driven rotor
or turbine. Extremely high speeds have been attained utilizing
pneumatically driven dental handpieces. However, one of the
problems that has arisen with the air driven dental handpieces is
that the turbine housing of the handpiece has been found to be too
large to enable the dentist to have complete facility of use of the
handpiece when working on the posterior teeth. The size of the
turbine housing has been limited, however, by the necessity for
supplying sufficient power to the rotating bur in order to permit
it to accomplish its intended work. Thus, it is a necessity to
sacrifice the size in order to obtain sufficient power for the
rotating bur.
In one aspect of the device of this invention, the diameter of the
turbine has been reduced 25%, while at the same time obtaining all
of the power of the larger diameter turbine. This is accomplished
by utilizing a turbine having blades with arcuate recesses formed
therein and by utilizing a dual or tandom jet of air directed
against the turbine blades.
In another aspect of this invention, an improvement is made in
connection with a wrench for rotating a collet to secure the dental
bur in place. In this aspect of the invention, the wrench is an
improvement on the wrenches disclosed in U.S. Pat. No. 3,120,706
and No. 3,325,899.
Originally, the collet used for securing a bur in an air driven
dental handpiece comprised an elastic sleeve formed from rubber or
plastic. The first improvement on the collet for an air driven
dental handpiece is that disclosed in aforementioned U.S. Pat. No.
3,120,706. In this patent, a collet is threadedly secured within
the rotor shaft. The collet is rotated relative to the shaft in
order to insert a bur and lock it in place or in order to remove
the bur.
As disclosed in this patent, the rotor is prevented from rotating
by a finger that is inserted through the rotor housing into the
rotor blades while a hexagonal wrench is inserted in the upper end
of the collet in order to rotate the collet.
An improvement on this type of rotor securement has been provided
by extending the lower end of the rotor shaft adjacent the position
in which the bur is inserted. This extension has a non-circular or
hexagonal cross-section. A wrench is fitted upon the extension to
hold the rotor stationary as the collet is rotatably adjusted
therein from the opposite end. The problem presented by this
structure is that the hexagonal extension, if made large enough for
secure attachment of a rotor-locking wrench, may cause serious
injury to a patient should the hexagonal surfaces contact oral
membranes or teeth during the high speed drilling operations. If,
on the other hand, the extension is reduced in size to minimize the
dangers to patients, the surfaces of the extension will be too
small to provide secure attachment for a wrench without rapid wear
or deformation.
A later improvement on the locking mechanism for the rotor is the
use of a unitary wrench which will lock the rotor in place and
provide a means for rotating the collet relative to the rotor. This
wrench is disclosed in aforementioned U.S. Pat. No. 3,325,899. This
wrench is advantageous in that there are no openings in the wall of
the turbine housing, and no extensions on the rotor shaft are
necessary. Instead, the wrench includes pins which pass through the
upper end cap on the turbine housing and into openings in a flange
on the rotor shaft. This locks the rotor shaft in place, and then a
stem having a hexagonal cross-section, which is inserted in the
upper end of the collet, is then rotated to expand or compress the
jaws of the collet.
The wrench of the device of this invention includes all of the
advantages of the device disclosed in U.S. Pat. No. 3,325,899,
while at the same time possessing a number of additional advantages
of its own. There are no locking pins on the device of this
invention, and accordingly it is unnecessary to have holes for the
pins in the end cap of the turbine housing. Instead, the opening in
the end cap is sufficiently large to permit a sleeve to pass
therethrough. The sleeve includes a pair of arcuate fingers that is
received in arcuate slots in the rotor. The wrench includes a
housing which is releasably secured on the turbine housing, and
since the sleeve is secured to the wrench housing, the rotor will
be prevented from rotating when the fingers of the sleeve are
inserted in the rotor. Thereafter, a stem having a hexagonal
cross-section is used to rotate the collet.
Since the wrench is not secured to the end cap, as is the case with
the pins passing through holes in the end cap, there is no fear of
loosening the end cap when the wrench is placed on the turbine
housing. Additionally, since the slots in the rotor are visible
from the exterior of the handpiece, there is no problem with
attempting to insert pins through the end cap and blindly insert
them in holes in an annular flange on the rotor. Additionally,
since no flange is necessary on the rotor of the device of this
invention, the height of the turbine housing is kept at a
minimum.
In a third aspect of the device of this invention, a novel fiber
optic system is provided for the handpiece. There are now fiber
optic systems in use on dental handpieces which are used to focus
light at the point where a rotating bur meets the tooth. The system
commonly in use comprises a fiber optic bundle that is secured on
the exterior of the handpiece by a clip. These units cause the
handpiece to be bulky and uncomfortable to use. Additionally, the
systems comprise a single light source at the terminus of the
system, and this can result in blockage of the light in use.
In the handpiece of this invention, the entire system is contained
within the handpiece, with the exception of two lights which
project from the handpiece and focus on the rotating bur. Having
the dual light sources possesses a number of advantages over the
single light source of the prior devices. Thus, there is no need to
adjust the lights when working in different intra-oral positions,
since there will be no total blockage of the light, as there is
with a single light source. Additionally, the dual light system
eliminates shadows on the bur, which occur with the single light
system. Another advantage of the device of this invention is that
the handpiece is readily usable with or without the fiber optic
system, and accordingly the fiber optic system will not interfere
in any way if a head without a fiber optic system replaces the one
with the fiber optic system.
It is accordingly an object of this invention to provide a novel
air driven dental handpiece.
It is another object of this invention to provide a novel wrench to
be used in combination with an air driven dental handpiece having a
threadedly secured collet in the rotor shaft.
It is a further object of this invention to provide a dental
handpiece having a novel fiber optic system therein.
It is yet a further object of this invention to provide an air
driven dental handpiece having a novel air supply for the
turbine.
These and other objects of this invention are accomplished by
providing a dental handpiece comprising a hollow handle, a turbine
housing mounted at one end of said handle, said turbine housing
having an air turbine rotatably mounted therein, and means within
said handle for delivering air to said turbine, said air delivering
means comprising a pair of spaced tubes in fluid communication with
said turbine housing, with each of said tubes being adapted to
supply air to rotate said turbine at different positions on said
turbine.
Other objects and many of the attendant advantages of this
invention will be readily appreciated as the same becomes better
understood by reference to the following detailed description when
considered in connection with the accompanying drawings
wherein:
FIG. 1 is an exploded side elevational view, partially broken away,
of the air driven dental handpiece and wrench of this
invention;
FIG. 2 is an enlarged sectional view taken along the line 2--2 of
FIG. 1;
FIG. 3 is a sectional view taken along the line 3--3 of FIG. 2;
FIG. 4 is an enlarged bottom plan view of the forward portion of
the air driven dental handpiece of this invention, and taken in the
direction of the line 4--4 of FIG. 1;
FIG. 5 is an enlarged sectional view taken along the line 5--5 of
FIG. 1;
FIG. 6 is a sectional view taken along the line 6--6 of FIG. 5;
FIG. 7 is a sectional view taken along the line 7--7 of FIG. 6;
FIG. 8 is an enlarged sectional view taken along the line 8--8 of
FIG. 6;
FIG. 9 is an exploded sectional view of the turbine and wrench of
the handpiece of this invention;
FIG. 10 is a top plan view of the turbine housing, and taken in the
direction of line 10--10 of FIG. 9;
FIG. 11 is a bottom plan view of the wrench, and taken in the
direction of line 11--11 of FIG. 9;
FIG. 12 is a sectional view showing the first position of the
wrench when it is mounted on the handpiece; and
FIG. 13 is a sectional view similar to FIG. 12, and showing the
final position of the wrench after its mounting on the
handpiece.
Referring now in greater detail to the various figures of the
drawings wherein like reference characters refer to like parts, an
air driven dental handpiece embodying the present invention is
generally shown at 20 in FIG. 1. Device 20 basically comprises a
handle 22 having a connector sleeve 28 secured at the rear thereof.
Handle 22 includes an angled neck 30 and a turbine housing 32
mounted perpendicularly to neck 30. A wrench used in connection
with the chucking mechanism of the turbine is generally shown at 34
in FIG. 1.
As best seen in FIG. 6, the handle 22 comprises a hollow tube, and
is externally threaded at its rear end, as shown at 36. An adaptor
nut 38 is threadedly secured on the rear end of handle 22. Adaptor
nut 38 includes an inwardly projecting annular shoulder 40. A
cylindrical portion 42 extends rearwardly on nut 38. Portion 42 is
externally threaded, as shown at 44. Connector sleeve 28 is
threadedly secured on cylindrical portion 42, and its forward end
abuts shoulder 46 on adaptor nut 38.
A plate 48 is positioned within handle 22 at the rear end thereof.
Spacer 48 includes an upper lip 50 and a lower lip 52. The spacer
is held in place by securing the lips 50 and 52 between the rear
edge 54 of handle 22 and shoulder 40 of adaptor nut 38.
As best seen in FIG. 7, an air tube 56, a water tube 58 and a fiber
optic bundle 60 pass through openings in plate 48. The fiber optic
bundle comprises a plurality of individual glass fibers having a
resilient plastic sleeve thereover. Preferably, the plastic sleeve
comprises an elastomeric impregnation which will soak into the
interstitial spaces between the individual fibers which are near
the periphery of the bundle and hold the bundle together, while
retaining flexibility. The elastomeric material can be any material
known to the art for coating and encapsulating light transmitting
glass fibers, such as a silicone rubber or polyvinyl chloride. The
glass fibers are shown schematically at 62 in FIG. 6 and the
elastomeric impregnant and covering sleeve is shown at 64 in FIG.
6.
A metal sleeve 66 is positioned at the rear end of the fiber optic
bundle 60 and telescoped thereover. Sleeve 66 includes a rear
annular lip 68. The sleeve 66 is adhesively secured to fiber optic
bundle 60. Sleeve 66 is slidably mounted in plate 48, and the lip
68 prevents the bundle from being pulled rearwardly out of plate
48.
Referring to FIG. 7, it is seen that plate 48 is non-circular in
cross-section. Thus, there is an opening 70 between one edge of
plate 48 and the internal wall of adaptor nut 38 and a second
opening 72 between the edge of plate 48 and the internal wall of
adaptor nut 38. Openings 70 and 72 provide a channel for the
exhausting of air that is used to drive the turbine, as will be
explained hereinafter.
At an intermediate point between sleeve 66 and the forward end of
handle 22, the glass fiber bundle 62 is split into two smaller
bundles 74 (FIG. 4). This is easily accomplished since the large
plurality of individual glass fibers can readily be divided or
bifurcated into two or more equal, or unequal, branches. The two
branches 74 of the glass fibers are then placed in stainless steel
tubes 76.
The glass fibers 62 and branches 74 form a Y-shaped junction 78
(FIG. 4). The glass fibers can be covered at the junction by any
means known to the art. The critical feature of the covering is
that the glass fibers not be exposed at that point. By way of
example, the fibers at the junction can be covered in the same
manner as the other fibers are covered, that is, impregnating and
coating the fibers with an elastomeric material. Alternatively, a
Y-shaped sleeve can be provided which will be cemented to the
stainless steel tubes 76 and the sleeve 64 covering the glass
fibers.
As seen in FIGS. 1 and 4, the stainless steel tubes 76 containing
the glass fiber bundles 74 therein extend along the handle 22, and
project from the handle adjacent a dental bur 80 which is secured
in the chucking mechanism of the turbine. As seen in FIG. 1, the
termini 82 of the tubes 76 are angled downwardly in the direction
of the dental bur. As seen in FIG. 4, the termini 82 are laterally
spaced on the bottom of neck 30 of handle 22. The glass fiber
bundles 74 terminate at apertures 84 at the ends of tubes 76. The
glass fibers are highly polished at the apertures. The glass fibers
are also highly polished at their other point of termination, which
is at the rear end of sleeve 66 (FIG. 6).
Referring to FIG. 6, it is seen that connector sleeve 28 includes
internal threads 88 which are threadedly secured on threads 44 of
adaptor nut 38. Sleeve 28 also includes an internal annular
shoulder 90. An adaptor plate 92 is slidably mounted in cylindrical
section 42 of adaptor nut 38. Plate 92 includes an upper lip 94 and
a lower lip 96 at the rear thereof. Lips 94 and 96 abut shoulder
90, and when connector sleeve 28 is threadedly secured in place,
the connector plate 92 is likewise secured in place by the shoulder
90.
As seen in FIG. 8, adaptor plate 92 has a metal water tube 98
secured therein, a metal air tube 100 secured therein and a fiber
optic bundle 102 secured therein. The metal tubes 98 and 100 are
welded or soldered in place, and the fiber optic bundle 102 is
adhesively secured in place. As seen in FIG. 6, a flexible tube 104
covers the fiber optic bundle, a flexible tube 106 is frictionally
held on air tube 100 and a flexible tube 108 (FIG. 1) is
frictionally held on water tube 98. The flexible tubes can be
formed from any of the fluid carrying materials known to the art,
such as rubber or polyvinyl chloride.
Referring again to FIG. 8, it is seen that there is an opening 110
formed between plate 92 and the internal wall of connector sleeve
28. Likewise, there is a second opening 112 formed between the
connector plate and the connector sleeve. Openings 110 and 70 and
openings 112 and 72 are respectively aligned with each other in
order to create conduits for the exhausting of air from the turbine
through the back of the handpiece.
A gasket 114 is positioned between plate 48 and plate 92. Gasket
114 is formed from rubber, and water tube 58 and air tube 56 pass
through the gasket. When the connector sleeve 28 is secured in
place with the connector 92 therein, the water tube and air tube
are received in channels within the connector. One of these
channels is shown at 116 in FIG. 6, with respect to air tube 56.
Metal sleeve 66 containing the fiber optic bundle 60 is cleared by
a notch 118 formed on the side of the gasket (FIG. 5).
When the connector sleeve 28 is secured on handle 22, along with
connector 92, sources of all of the media needed for the operation
of the handpiece are automatically secured in place. Thus, air and
water are supplied through flexible tubes 106 and 108 to tubes 56
and 58, respectively. The gasket 114 provides a fluid-tight
connection for these tubes. The tubes 106 and 108 are also
connected to suitable sources of air and water, as is common in the
art.
One of the features of the device of this invention is the manner
of supplying light to the fiber optic bundle 60. Thus, when the
connector 92 is secured in place, the leading face of fiber optic
bundle 102, which is highly polished, is automatically brought into
alignment with the trailing face of the fiber optic bundle 60,
which is adjacent gasket 114. As pointed out above, the sleeve 66
containing the fiber optic bundle 60 is slidably mounted within
plate 48, and normally projects slightly beyond the rear edge of
gasket 114. When the connector is secured in the position shown in
FIG. 6, the leading edge of the bundle 102 contacts the trailing
edge of the bundle 60, and slightly compresses the bundle in view
of the slidable mounting of the sleeve 66 in plate 48. Thus, the
resilient nature of the elastomeric sleeve 64 of bundle 60 tends to
force the bundle rearwardly through the opening in plate 48. The
rearward movement is stopped by the abutment of lip 68 of sleeve 66
against the plate 48. When the bundle 102 is brought in contact
with sleeve 66, the sleeve 66 is pushed forwardly against the
urging of the elastomeric sleeve. This assures good contact of the
abutting faces of the fiber optic bundles and therefore effective
light transmission through the interface of the two bundles.
The plastic tube 104 carrying the fiber optic bundle 102 is mounted
at its remote end to a light source, in a manner common to all
fiber optic systems. This light source is generally a lamp which is
focused on the fiber optic bundle, and the bundle 102 will in turn
transmit the light to the bundle 60. The light then emanates from
the apertures 84 (FIG. 4) in the exposed termini 82 of the steel
tubes 76. This light will then illuminate the area around the
rotating dental bur 80.
Referring to FIG. 1, it is seen that water tube 58, which is rigid,
is connected through flexible tubing 122 to a rigid spray tube 120
(FIG. 4). Likewise, a rigid tube 124 (FIG. 1) is tapped into air
tube 56. Tube 124 is connected to a rigid spray tube 126 by
flexible tubing 128. Tubes 120 and 126 are secured to a clip 130,
which is in turn slidably mounted on neck portion 30 of handle
22.
Tubes 120 and 126 each contain downwardly disposed apertures 132 at
the ends thereof. The tubes 120 and 126 are slidable into and out
of the area of the bur 80 by sliding the clip 130 on neck portion
30. The sliding is accomplishable in view of the fact that the
flexible tubes 122 and 128 can be contracted or expanded. When the
spray system is in use, water will be expelled through the
apertures in tube 120 and air will be expelled through the
apertures in tube 126. The air will then atomize the water into a
mist.
The spray system used on the handpiece of this invention is old in
the art, and in itself forms no part of the invention. For further
description of the spray system, reference is made to U.S. Pat. No.
3,120,706 and No. 3,199,196, the disclosures of which are
incorporated by reference herein. Any spray system known to the art
can be used with the handpiece of this invention.
As best seen in FIGS. 2, 3 and 9, turbine housing 32 is basically
cylindrical, and projects perpendicularly to neck portion 30 of
handle 22. Housing 32 has an end cap 134 threadedly secured on its
top and an end cap 136 threadedly secured at its bottom. End cap
134 includes a central opening 138 for the reception of a chuck
wrench, as will be explained hereinafter. End cap 136 also has a
central opening 140, through which dental bur 80 is inserted.
A turbine cartridge 142 is inserted in turbine housing 32 by
removing the end caps 134 and 136, and sliding the cartridge in
place. As best seen in FIG. 9, the cartridge comprises a rotor
shaft 144 having a collet 146 threadedly secured therein. A rotor
having a hub 148 and spaced blades 150 is keyed to rotor shaft 144
on the outer surface thereof. Rotor shaft 144 is mounted in an
upper ball bearing 152 and a lower ball bearing 154. The turbine
cartridge comprises a single unit consisting of the upper and lower
ball bearings, the rotor, the rotor shaft and the collet. This unit
is integrally insertable and removable from the turbine housing
32.
To the extent described, the turbine cartridge is the same as that
disclosed in U.S. Pat. No. 3,120,706. The insertion and removal of
the turbine cartridge are discussed in further detail in said
patent. As explained in said patent, the rotor shaft 144 includes
an inwardly tapering wall 156 at its bottom. Likewise, the exterior
wall of the collet sleeve 146 is inwardly tapering, as shown at 158
in FIG. 9. The collet includes a pair of diametrically opposed
slots (one shown in phantom at 160 in FIG. 9), which slots divide
the collet into a pair of jaws. The top of collet 146 is provided
with a bore 162 of non-circular cross-section. In the embodiment of
the invention shown, the bore has a hexagonal cross-section. As
will be explained hereinafter, the rotation of the collet 146 in
rotor shaft 144 causes the compression of the jaws of the collet,
thereby securing the shaft of bur 80 within the collet.
As seen in FIG. 9, ball bearings 152 and 154 each comprise an inner
race 164, an outer race 166 and a plurality of balls 168. The outer
races 166 are contacted by the inner surfaces of the end caps 134
and 136 when the turbine cartridge is secured in place. However,
each end cap is provided with an internal recess whereby the end
caps will not be contacted by the inner races 164. Accordingly, the
rotor shaft is freely rotatable, along with the inner races,
between the end caps 134 and 136.
As seen in FIG. 2, air tube 56 is provided with a coupling 170 at
its inner end. A pair of rigid tubes 172 and 174 is mounted in
coupling 170 and projects therefrom. As seen in FIG. 2, tubes 172
and 174 are mounted in horizontally aligned openings in turbine
housing 32. As further seen in FIG. 2, the tubes 172 and 174
project angularly into the turbine housing, and in the direction of
rotation of the rotor blades 150.
As seen in FIG. 3, turbine housing 32 includes a pair of openings
176 and 178. These openings are positioned above and below tube
172, and place the interior of neck 30 in fluid communication with
the interior of turbine housing 32. Openings 176 and 178 are used
for exhausting the air which drives the rotor.
The rotor in the handpiece of this invention is a Pelton wheel.
Thus, as seen in FIG. 3, each rotor blade 150 includes a pair of
aligned recesses 180. The advantage of having the recesses in the
rotor blades in that a greater amount of energy is extracted from
the moving air in turning the rotor when the air contacts the
recessed blades, as opposed to contacting the flat blades of the
prior art. As seen in FIG. 3, the recesses 178 extend axially on
the rotor blades.
The details of the wrench 34 are best seen in FIG. 9. Thus, as seen
therein, the wrench 34 comprises a housing 182, a tube 184 secured
in a central opening in the housing and projecting vertically, a
shaft 186 rotatably mounted in tube 184 and a cap 188 secured to
the shaft 186. Housing 182 includes a lower cavity 190 which is
basically circular in cross-section. Cavity 190 has an internal
diameter which is slightly larger than the external diameter of
turbine housing 32. An arcuate slot 192 is formed in cavity 190. An
annular groove is formed on the wall of cavity 190, and a circular
spring 194 is mounted in the groove. Spring 194 is provided with a
cut 196 therethrough, in order to permit for the expansion of the
spring when the wrench 34 is secured in place.
Tube 184 is secured in housing 182, and includes a pair of
diametrically opposed slots 198 at the bottom thereof (see FIG.
11). A pair of downwardly projecting fingers 200 is formed by the
slots 198. Shaft 186 has a hexagonal cross-section. This is the
same cross-section as the cross-section of bore 162 of collet 146.
Shaft 186 can have any non-circular cross-section, which
cross-section, however, should be the same as the cross-section of
the bore 162.
A sleeve 202 is keyed to shaft 186 and is positioned within tube
184. Tube 184 includes an inwardly projecting annular lip 204 at
the top thereof. Cap 188 is also keyed to shaft 186. Thus, sleeve
202 prevents shaft 186 from being pulled upwardly through the top
of tube 104 by the abutment of the sleeve against lip 204, and cap
188 prevents the shaft 186 from falling downwardly through tube
184. The rotation of cap 188 will in turn rotate shaft 186, and its
associated sleeve 202, within tube 184.
Rotor shaft 144 is provided with a pair of slots 208 (FIG. 10) at
the top thereof. Each slot 208 is slightly larger than a finger 198
on tube 184. As seen in FIG. 10, slots 208 are accessible through
opening 138 in end cap 134. Neck 30 of handle 22 is provided with a
recess 210 at its top.
The use of wrench 34 is shown in FIGS. 12 and 13. As seen in FIG.
12, housing 182 is slid downwardly over turbine housing 32, in the
direction of arrow 212. Shaft 186 automatically enters bore 162 in
collet 146 when this is done. The bottom of rotor shaft 144, which
projects slightly through end cap 136 is then rotated until the
fingers 200 are aligned with slots 208 in rotor shaft 144. When
this occurs, downward pressure on housing 182 is continued, in the
direction of arrows 214 of FIG. 13, until the fingers are received
in the slots.
The final, secured position for the wrench 34 is shown in FIG. 13.
As seen therein, the spring ring 194 has been expanded, and
securely clamps the side wall of upper end cap 134. The wall of
slot 192 of housing 182 is received in recess 210 of neck 30. The
opening 138 in end cap 134 is sufficiently large to permit the
insertion of tube 184 through the end cap.
After the wrench has been secured in place, it is ready for use in
securing or removing a bur 80 from collet 146. Referring again to
FIG. 13, once the shaft of bur 80 has been inserted in collet 146,
cap 188 is rotated in a clockwise direction, as indicated by arrow
216. The rotation of the cap will in turn rotate shaft 186 and its
associated sleeve 202. Since the shaft is received in the bore 162
of collet 146, the collet will also be rotated in a clockwise
direction. The rotor 144 will be prevented from rotating by the
engagement of fingers 200 in slots 208 of the rotor. Thus, the tube
184 is held rigidly in place by the engagement of the housing 182
on the turbine housing and by the abutment of the wall of slot 192
against neck 30 of the handle of the handpiece. Accordingly, the
collet will rotate relative to the rotor shaft.
The rotation of the collet in a clockwise direction will move the
collet vertically downward within the rotor shaft. The abutment of
the tapered wall 158 of the collet against the tapered wall 156 of
the rotor shaft will compress the jaws of the collet. This in turn
will securely clamp the dental bur within the collet. At this
point, when the turbine is rotated, the dental bur will be rotated
therewith.
When it is desired to remove the dental bur, the wrench 34 is
secured in place in the manner described above. However, the cap
188 is rotated in a counterclockwise direction. This raises the
collet vertically within the rotor shaft, thereby permitting the
jaws to expand. With the jaws thus expanded, the dental bur 80 will
drop out of the collet. A new collet can then be inserted and
tightened in the manner described above.
The wrench 34 of this invention possesses a number of advantages
over the similar wrenches presently in use. Since the tube 184 is
inserted directly through a large opening in the end cap 134, there
is no problem with the attempted blind alignment of pins through
small openings in the end cap and into openings in the top of a
flange on the rotor. Additionally, since slots are provided
directly in the top of the rotor, which slots are visible through
the opening 138 in end cap 134, there is no need for the flange at
the top of the rotor. This permits the use of a smaller height to
the turbine housing, since no room need be provided for the rotor
flange.
The air turbine is operated in the same manner as the prior art air
turbines. The control for the air can be any of the conventional
controls, such as a foot pedal. The air for driving the turbine
enters the handpiece through tube 106, and then passes into tube
56. As seen in FIG. 2, the air is split and emanates from tubes 172
and 174 against a pair of adjacent rotor blades 150. The air is
received in the arcuate recesses 178 of the rotor blades, and will
drive the rotor or turbine.
As seen in FIG. 3, after the air is used to rotate the turbine, it
is exhausted through openings or ports 176 and 178. It then passes
rearwardly through the hollow handle 22, and is exhausted through
the open end of connector sleeve 28. Referring to FIGS. 7 and 8, it
is seen that the openings on the sides of plates 48 and 92 provide
channels for the exhausting of the air.
The fiber optic system utilized in this invention includes glass
fiber bundles. The glass fibers are preferred because they are
autoclavable, and will encounter less scratching in use. However,
any light transmitting fibers known to the art can be used in
carrying out this invention. Thus, plastic fibers, such as
polymethyl methacrylate, can also be used. These fibers can be
encapsulated and sheathed in any resilient jacket, such as
polyethylene, a silicone resin or polyvinyl chloride.
Having the dual light sources at apertures 84 (FIG. 4) insures
continued lighting of the area of the mouth being treated,
regardless of the angle at which the dentist holds the handpiece.
Thus, if one of the light sources is blocked, the other will not
be. There is no need for continual readjustment of the light
source, as is necessary when using the externally clipped fiber
optic system presently in use. The fiber optic system of this
invention is contained entirely within the handpiece, and is not
disturbed during use. The rigid termini 82 of the stainless steel
tube 76 are held securely in place in the position shown in FIG.
4.
The fiber optic system of this invention enjoys all of the other
advantages of the prior art fiber optic system. Thus, light is
transmitted from a remote source, and is easily carried around
bends or curves. Thus, regardless of the manner in which the
dentist will twist the handpiece, the fiber optic systems will
still carry light from its light source, which is at a remote
point, such as on the dentist's console.
The manner of connecting the fiber optic system, as best seen in
FIG. 6, is also unique. The handpiece can be used either with or
without a source of light and a fiber optic system. Thus, the
handpiece can be coupled to an air and water supply, without being
coupled to a light source, and still carry out its intended
functions. Likewise, a handpiece without the fiber optic system can
be connected to the connector plate 92. The coupling of the fiber
optic system to the light source is automatic when the connector is
secured in place, and the resilient abutment of the glass fiber
bundle 102 with the end of the glass fiber bundle 60 insures
efficient light transmission and continuity.
Without further elaboration, the foregoing will so fully illustrate
our invention, that others may, by applying current or future
knowledge, readily adapt the same for use under various conditions
of service.
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