Note: Descriptions are shown in the official language in which they were submitted.
ROTARY TYPE~S~L;~CONTAlNED
PORTABLE DENTAL lNSTRUMENT
The invention is related to portable rotary type self-contained
dental instruments of the type used to perform rotary work on teeth such
as cleaning, polishing, or cutting. Numerous types of portable dental
instruments are known in the prior art as operable for powering rotary
type dental instruments to perform operations on teeth or dentures and
the like. The prior art devices are constructed to use rotary dental tools
of a conventional structure such as contra angle prophylaxis head mounting
same in a rigid position relative to the hand held portion of the device.
The prior art devices have miniature electric motors, such as a DC motor
and a storage battery therein with the shaft of the motor directly connected
with the shaft of the rotary dental tool. The prior art devices use a small
high speed direct current electric motor with the shaft thereof directly
connected by a shaft coupler to the shaft of the contra angle dévice or the
like so the shaft of the rotary tool is rotated at the same speed as the electric
motor. Typically, the small high speed direct current electric motor is
used in the prior art devices; these motors typically have a relatively low
operating torque at the operating speeds and stall when under a load such as
in cutting, cleaning, and polishing operations. A direct current motor used
for driving such prior art devices can be operated at speeds of approximately
12,000 revolutions per minute or more and require a working voltage of up
to 30 volts for such operation. Some prior art dental instruments utilize a
remotely connected battery or source of power for the motor in the hand-
piece. This type of portable device is somewhat portable; however, it is
cumbersome in that the battery pack or whatever source of power is used
must be carried by the person using the instrument and connected by a
flexible cord or the like. Some of the prior art devices are provided with
a variable resistor in the electrical circuit thereof between the battery and
the motor for controlling the operating speed of the instrument. Controlling
the speed of the instrument by changing the electrical power supplied to the
motor reduces the output torque or output power characteristics of the motor
. ~
.~ -2- ~
036~4s
~s well as decreasing the operating speed of the motor and of the instrument.
Reducing the speed of the instrument by thls means is not desirable because
this type of motor has inherently a relatively low torque and reducing the
speed proportionally reduces the torque more.
The dental instrument of this invention as disclosed herein includes
several embodiments of the basic instrument invention; in all cases the
structure includes a hand-piece with an electric motor mounted therein, a
source of power mounted in the hand-piece, a rotary dental tool mount on
the hand-piece for removably mountlng a rotary dental tool or the llke in
10 an operating position and further including a speed changing apparatus to
mechanlcally change the operating speed of the output sha$ to which the
rotary dental tool or the like is attached relative to the operating speed of
the motor. In one preferred specific embodiment, a dental instrument
structure includes a motor and a battery mounted in the hand-piece in line
in the hand-piece or handle, a rotatably mounted shaft connected by pulleys
and a belt with the operating shaft of the motor, a~ mount for the rotary
dental tool or the like to be driven from the rotatably mounted shaft, and with
a control swltch on the handle or hand-piece. In another preferred specific
embodiment, a dental instrument includes a motor and battery mounted in
20 the hand-piece or handle in an in-line fashion, a rotatably mounted output
shaft connected by a belt and pulleys with the motors of the output shaft, a
mount for the rotatable dental tool or the like with a control switch mounted
on the hand-piece and a second control switch mounted on the rotatable
dental tool mount. In another preferred specific embodiment, a dental instru-
ment structure includes a battery and a motor in a juxtapositional relation
in the handle or hand-piece, a rotatable output shaft connected by a belt and
pulleys with the motor's output shaft, a mount for the rotatable dental tool
or the like, a battery recharging device and a control switch mounted on the
hand-piece. In another preferred specific embodiment a dental instrument
30 structure includes a battery and a motor mounted in a handle or hand-piece,
-3--
~~ ~
` ~, 1036845
c~, ratatably mounted output shaft and a rotatably mounted intermediate shaft
which is connected by a belt and pulleys with the motor's output shaft and
another belt and other pulleys connected with the rotatably mounted output
shaft, a mount for the rotatable dental tool or the like and a control switch.
Another preferred specific embodiment of the dental instrument structure
includes a pair of power cells and a motor mounted in the handle or hand-
piece, a rotatably mounted output shaft connected by a belt and pulleys with
the motor output shaft, a mount for the rotatable dental tool or the like and
a pair of control switches to connect one or both of the power cells with the
10 motor to provlde for a two-speed operation.
One object of this invention is to provide a dental instrument structure
overcoming the aforementioned disadvantages of the prior art devices.
Still, one other object of this invention is to provide a portable dental
instrument structure having a mechanical speed changing apparatus between
the powering motor of the instrument and the output shaft of the instrument.
Still, another object of this invention is to provide a dental instrument
of a portable nature whlch has a mount for a rotatable dental tool or the like
whlch wlll mount the contra angle piece or the like in a rigid position with
the hand-piece or handle of the dental instrument yet be rotatable by finger
20 pressure about its axis of support for operation of the dental instrument with
a rotatable dental tool in a position about the axis of rotation of the mount.
Still, another object of this invention is to provide a dental instrument
of a portable nature which has a rotatable dental tool mount with a control
switch thereon operable to control the motor of the dental instrument by
finger pressure.
Still, another object of this invention is to provide a dental instrument
having a pair of power cells in the battery thereof connected to the motor
thereof by separate control switches to provide a portable self-contained
dental instrument for mounting a rotatable dental tool or the like which has
30 two operating speeds.
.,. 103~5
Yet, another object of this invention is to provide a dental lnstrument
of a portable nature to provide a rotary power for operatlng a rotatable
dental tool or the like which has a pulley mounted with the output shaft of
the motor in the hand-piece, a second pulley mounted with the output shaft
of the dental instrument with the pulleys being connected by an endless belt.
Yet, another object of this invention is to provide a dental instrument
of a portable nature to provide rotational power for operating a rotatable
dental tool or the llke which has two sets of belts and pulleys connecting
the output of a motor in the hand-piece or handle of the instrument through
10 an lntermediate shaft to the output shaft of the instrument for providing
rotational motion to operate the contra angle piece or the like.
Various other objects, advantages, and features of the invention
will become apparent to those skilled in the art from the following discussion
taken in conjunction with the accompanying drawings, in which:
Fig. 1 is a side elevation view of an embodiment of the dental instru-
ment having portions thereof cut away for clarity, with the motor and battery
portlons thereof shown ln dashed llnes, the instrument havlng a straight
shank type prophylaxis head rotatable dental tool;
Fig. 2 is a side elevation view of the dental instrument shown in
20 Fig. 1 with the rotatable dental tool pivoted on the mount;
~ ig. 3 is a cross-sectional view of the dental instrument shown in
~igs. 1 and 2, taken on line 3-3 of l~ig. 2;
Fig. 4 is a schematic diagram of the electrical circuit of the dental
instrument shown in Fig. l;
Fig. 5 is a side elevation view of an embodiment of the dental instru-
ment having a control switch on the tool mount, with portions thereof cut
away for clarity, the dental instrument having a contra angle prophylaxis
head rotatable dental tool;
l~ig. 6 is a side elevation view of the dental instrument shown in
30 l~ig. 5;
--5--
1036845
Fig. 7 is a top plan view of the dental instrument shown in Figs. 5
and 6 without a rotatable dental tool;
E;ig. 8 is a schematic diagram of the electrical circuit for the
dental instrument shown in Fig. 5;
l~ig. 9 is a side elevation view of an embodiment of the dental instru-
ment with the motor and the batteries thereof in juxtapositional relation as
shown in dashed lines, the dental instrument having portions thereof cut
away for clarity and fitted with a contra angle drill rotatable dental tool;
Flg. 10 is a side elevation view of the lower portion of the dental
10 lnstrument shown in Fig. 9;
l~ig. 11 is a top plan view of the dental instrument shown in Fig. 9
with the upper por~ion of the rotatable dental tool removed;
l~ig. 12 is a side elevation view of an embodiment of the dental
instrument having four pulleys and an intermediate shaft connecting the
motor and the dental instrument output shaft;
~ ig. 13 is a side elevation view of the dental instrument shown in
Flg. 12;
Fig. 14 is a cross-sectional elevation view taken longitudinally of
the resilient coupler member used to connect the output shaft of the dental
20 instrument and the shaft of the rotatable dental tool;
~ ig. 15 is a side elevation view of an embodiment of the dental
instrument which is constructed for two speed operation and has a control
switch on the mount thereof, with portions of the dental instrument and the
rotatable dental tool mounted thereon cut away for clarity;
Fig. 16 is a side elevation view of the dental instrument shown in
~ig. 15 with the instrument in a stand structure having a battery charging
apparatus, with portions of the stand structure cut away for clarity;
~ ig. 17 is a top plan view of the dental instrument shown in Fig. 15
with the prophylaxis head turned slightly from the position shown in Fig. 15;
30 and
--6--
1036845
l~ig. 18 is a schematic diagram of the electrical circui~ of the
dental instrument shown in ~ig. lS.
The following is a discussion and description of preferred specific
embodiments of the dental instrument structure of this invention such
being made with reference to the drawings, whereupon the same reference
numerals are used to indicate the same or similar parts and/or structure.
It is to be understood that such discussion and description is not to unduly
llmlt the scope of the invention.
The dental instrument of this invention is shown and disclosed
10 herein in five, (5), embodiments thereof which are closely related. An
embodiment, (1), of the dental instrument is shown on Sheet 1 of the
drawings and is generally indicated at 10. Another embodiment, (2), of
the dental instrument, indicated generally at 12 and is shown on Sheet 2
of the drawings in Figs. 5-8. Another embodiment, (3), of the dental instru-
ment of this invention is shown on Sheet 2 of the drawings generally indicated
at 14 and shown in ~igs. 9-11. Another embodiment, (4), of the dental
~nstrument of this invention is shown on Sheet 3 of the drawings, generally
indicated at 16, and shown in ~igs. 12 and 13. Another embodiment, (5),
of the dental instrument of this invention is generally indicated at 18 and
20 shown on Sheet 4 of the drawings.
The embodiment of the dental instrument, (1), shown on Sheet 1 of
the drawings and generally indicated at 10 is the most basic of the several
embodiments of the dental instrument of this invention. The dental instrument
10 includes a handle or hand-piece 20 with a chuck or mount 22 on the upper
portion thereof ~o mount a rotary dental tool head such as the prophylaxis
angle shown, and in the handle or hand-piece 20 a speed changing apparatus
26. The dental instrument 10 is shown with straight shank type prophylaxis
angle tool mounted therewith to illustrate one of the multiplicity of rotary
dental tools which can be operated with the dental instrument of this
30 invention.
--7--
- ~036s4s
The handle or hand-piece 20 includes the motor 28 and battery 30
as shown in dashed lines within the handle-like enclosure portion 32 of the
structure. The upper portion of the handle or hand-piece 20 is a hollow
enclosure 34 which encloses a speed changing apparatus 26 and supports a
portion of the chuck or mount 22. The motor 28 has a shaft 36 extending
therefrom into the hollow enclosure 34 with a pulley 38 mounted on its end
portion. The dental instrument 10 has an output shaft 40 mounted as shown
on bearlngs 42 and 44. A second pulley 46 is secured to the output shaft 40
and is connected by an endless belt 48 with the motor pulley 38. The bearings
10 44 and 42 are preferably low-friction roller bearings or ball bearings which
can be easily rotated by the roller 28. As shown in Figs. 1 and 3 the motor
pulley 38 is substantially smaller than the second pulley 46 so the output
shaft 40 is rotated at a slower speed than the motor 28. A support for the
hollow enclosure is attached to the side of the handle or hand-piece 20 as
indlcated at 43 to provide structural support for the output shaft and the
hollow enclosure 34 on the end of the hand-piece 20. The ratio of the motor
pulley 38 or drive pulley to the second pulley 46 or driven pulley is preferably
in the range of 2:1 to 5:1 as such has been found in pract ice to provide output
shaft rotatlng speeds suitable for prophylaxis, cutting and polishing of teeth,
20 dentures, and the like.
The structure of the chuck or mount 22 of the dental instrument 10
has an important feature of the dental instrument. The structure of the
chuck or mount 22 allows a rotary dental tool 24 to be easily mounted with
and removed from the dental instrument and rotated about the axis of the
attachment of the tool to a convenient position and retained in that position.
The mount has a base 50 secured to the end 52 of the hollow enclosure 34
and a removable portion attachable to the rotatable dental tool. The base 50
has a flat portion secured to the end 52 and an upturned and exteriorly
threaded portion 54 surrounding the instrument output shaft 40. The
30 removable portion of the mount is attachable to the base 50. The removable
--8--
' ` -` 103~845
portion of the mount 22 is indicated generally at 51 and is connectable
between the base 50 and the rotary tool 24 and includes an inner threaded
member 56, a sleeve 58 and an outer portion 60. The inner threaded
member 56 is engagable with the exteriorly threaded portion 54 of the
base 50. The sleeve 58 is expanded on its lower portion to encircle the
lnner threaded member 56 and ls of a reduced size in a cylindrical portion
62 on ~ts oppo~ite end portlon. The outer member 60 surrounds a lower
portion of the sleeve 58 and on its upper portion 64 is spaced from the
cyllndrical portion 62 of the sleeve. Preferably, the inner threaded member
56, the sleeve 58, and the outer member 60 of the removable portion of the
mount are bonded together in a unit-like structure. The output shaft 40
has an upper end portion indicated at 66 which extends into the mount 22.
The rotary dental tool 24 has a shaft 68 through the center portion thereof
by which rotary power is transmitted. The rotary tool 24 has a barrel- like
~tructure 70 surrounding the shaft 68 with an enlarged collar 72 on its lower
portlon that slldes over the cylindrlcal portlon 62 of the sleeve 58 in an
lnterference fit. The interference flt between the collar 72 and the
cylindrical portion 62 of the mounts is sufficiently tight to retain the rotary
dental tool 24 in position on the mount 22 yet allow it to be rotatable on the
mount 22. The collar 72 slides on the cylindrical portion 62 so that the tool
can be pi~sitioned as desired by finger pressure on the collar portion 72
of the tool 24. ~ig. 2 shows the prophylaxis head rotatable tool having the
cup 74 thereof rotated to a position different from that shown in Fig. l to
exemplify the positionability of the tool. A resilient coupler indicated at 76
connects the upper end portion 66 of the output shaft and the tool shaft 68.
~ig. 14 on Sheet 3 of the drawings shows the resilient coupler in
detail. The resilient coupler is indicated generally at 77 and illustrates
the preferred coupler used with all embodiments of this invention. The
coupler 77 is preferably a resilient member of synthetic rubber or neoprene
or other suitable material formed as shown. Preferably, the coupler has a
`' 1036~45
S~;Xd center portion 78 and similar end portions to receive the end portions
of the shaft. The coupler as shown in Fig. 14 has a solid center portion 78
and similarly constructed opposite end portions with the outer wall thereof
indicated at 80 and the interior wall thereof indicated at 82. Preferably, in
use the shafts of the tool and the dental instrument will extend into the
coupler 77 with the ends of the shafts contactable or in a closely adjacent
relation to the solid center portion 78. It is preferable, but not necessary
that the coupler 77 be of a cylindrical construction,
Power for the dental instrument 10 is provided by the battery 30.
10 A control switch 75 preferably mounted on a side portion of the handle-like
enclosure portion 32 of the dental instrument. The control switch 75 is
connected as shown in the schematic diagram in Fig. 4 in a series relation
with the motor 28 and the battery 30. The control switch 75 is preferably
a push-button type switch to control on and off operation of the motor 28.
The motor 28 is preferably a direct current electric motor of a relatively
high speed powered by the battery 30. The battery 30 is preferably
permanently mounted in the hand-piece structure 20 and is of a rechargeable
type. The lower end portion of the hand-piece enclosure 32 is preferably
provided with an induction coil 79 connected with the battery 30 and usable
20 for recharging of the battery. The lower portion of the hand-piece enclosure
32 has a small cavity 80 used for support of the hand-piece on a mount or
supporting standO The induction coil battery recharging apparatus 79 is
shown in a rectangle of dashed lines in ~ig. 4 and illustrates the preferred
apparatus for recharging the battery. It is to be understood that a re-
charging appara~us other than the reduction coil type can be used with the
dental instrument 10. In practice it has been found that the induction coil
type recharging apparatus provides a convenient and simple means of
recharging the battery 30. It is to be noted that if desired the control switch
75 can be replaced by a rheostat with an on-off swi~ch included to provide a
30 variable speed control for the motor 28 without departing from the scope of
the invention.
- 10-
- 10368~5
In practice in using the dental instrument 10 of this invention, such
has been accomplished by the use of a small electric motor of the general
size used in portable electric toothbrushes and with a battery of a similar
type. In this practice of the invention the motor has a rotation speed of
approximately 8, 000 to 10, 000 revolutions per minute and the output sha*
of the dental instrument has a rotating speed of approximately 400 revolutions
per minute to 600 revolutions per minute which has proven to be adequate
for dental prophylaxis. Typically, rotating tool speeds for dental prophy-
laxis are in the range of 400 revolutions per minute to 5, 000 revolutions
10 per mlnute. Rotating tool speeds for cutting and polishing operations on
teeth and the like are in the range of 5, 000 revolutions per minute to
30, 000 revolutions per minute. In the use of the dental instrument 10 for
prophylaxis the speed changing apparatus 26 enables the motor 2~ to
operate at a very high speed where it has favorable torque characteristics
and the output shaft 40 rotates at a speed which is favorable for prophylaxis.
Inasmuch as the dental instrument of all the herein disclosed
embod~ments are provlded w{th a dlrect current electric motor, lncreasing
or decreasing the voltage and power capacity of the battery will cause the
motor to rotate at a higher speed or a lower speed thereby raising or
20 lowering the output rotating speed of the tool. The battery used with the
dental instrument can be of a voltage and power capacity to sustain operation
of the motor at the upper speed range requirement for the use for which
the instrument is intended, such as drilling and a rheostat or variable
resistor used to reduce the tool speed as required or as desired. It is to
be noted that the dental instrument can be provided with means to modify the
capacity of the battery such as by adding or removiElg individual power cells
in the battery. The dental instrument 10 can be constructed to receive and
hold a single replaceable dry cell or a plurality of replaceable dry cells.
The dental instrument 10 of this invention is completely portable
30 and can easily be held in a person's hand. The dental instrument 10 can
1036B45
be grasped and operated between the thumb and the fingers either in the
palm of the hand or above the hand. Posltioning of the control switch 75
on the side of the handle or hand-piece 20 makes it conveniently pressable
as the dental instrument is grasped and held. The handle or hand-piece
20 is constructed such that it can be held in the palm of the hand by the
fingers and the control switch 75 can be operated by the thumb which is
convenient and safe considering some dental operations and procedures
requlre quick motions and relatively rapid reflex action on the part of the
dentist.
Another embodiment, (2), of the dental instrument of this invention
is indlcated at 12 and is shown on Sheet 2 of the drawings in l~igs. 5-8
thereof. The dental instrument 12 of this embodiment of this invention is
basically similar to the hereinbefore described first embodimen., (1), of
the dental instrument of this invention and further includes a second control
swltch on the tool mount portion of the structure in addition to the control
switch on the hand-piece portion of the structure. The dental instrument 12
includes a handle or hand-piece 90 enclosing the motor and battery in an
interlor portion thereof on one end and on its opposite end portion a hollow
enclosure for the speed changing apparatus 92. The rotatable tool mount
94 or chuck is on the upper portion of the handle or hand-piece 90; it has a
control switch thereon and is adapted to removably engage in a rotatable
operating position the rotatable dental tool such as the contra angle prophylaxis
tool shown. The dental instrument 12 is constructed so that it can be held
in the hand and operated by the control switch on the side of the handle or
hand-piece 90 or held in the hand and operated by the control swltch on
mount 94. The control switch on the mount 94 makes it possible to support
the dental instrument 12 in a balanced condition as may be comfortable or
necessary for precision movements of the rotary dental tool or for comfort
of the user.
The hand-piece or handle 90 is provided with an enclosure portion 97
036~4S
wltj~ch encloses a motor 98, a battery 100 and preferably an induction coil
recharging device 102 as illustrated in the schematic diagram in ~ig. 8.
The control switch 103 is provided on the side of the handle-like enclosure
97 to control the motor 98. The motor 98, battery 100, and recharging
apparatus 102 al e preferably constructed similar to that shown in Figs. 1
and 2 and described in conjunction with the first described embodiment, (1).
The speed changing apparatus 92 connects the motor 98 to an output shaft
for the dental instrument. The motor 98 has an output shaft 104 with a
pulley 106 secured thereto and positioned in the hollow portion of the hand-
piece adjacent to the end indicated at 108. The output shaft of the dental
instrument is indicated at 110 and is supported by the roller bearings 112
and 114 in the hand-piece end enclosure. A pulley 116 is secured to the
rotatably mounted output shaft 110 and connected by a belt 118 with the
motor pulley 106. The output shaft extends from the handle or hand-piece
90 as shown and into a portion of the mount 94.
The mount 94 or chuck has a base member 120 secured to the end
108 and a removable portion indicated generally at 119. The base 121
includes an upwardly extendlng anl externally threaded center portion 121
on which a removable portion of the mount 94 is attachable. The mount or
chuck removable portion 119 includes an internally threaded member 122
engagable with the externally threaded portion 121 of the mount basè 120,
a sleeve 124 expanded on its lower end portion to fit over the threaded
member 122 cylindrical on its upper end portion 126 and an outer member
128 expanded on ~ts lower portion 130 around the sleeve 124 and internally
cylindrical on its upper portion 132 and having the second control switch
134 mounted on its upper portion 132. The interior of the outer member
upper portion 132 is preferably cylindrical as indicated at 136 and is sized
to be spaced from the exterior of the rotatable tool as shown. The rotatable
tool 96 as shown is a typical contra angle prophylaxis tool and has a barrel
portion 138 with a shaft 140 contrally disposed therein, with the barrel 138
-13-
03684s
betng used to connect the tool and support the tool with a powering device.
The cylindrical sleeve 126 fits inside of the barrel 138 as shown in an
interference fit which is sufficiently tight to retain the tool in position
yet allow for rotation of the barrel 138 relative to the sleeve 126 and the
chuck or mount 94 by finger pressure. The upper end of the dental instru-
ment output shaft 110 is indicated at 142 and extends into the interior of
the mount 94. A resilient coupler member 144 connects the output shaft
end p~rtlon 142 with the shaft 140 of the rotary dental tool 96. The resilient
coupler 144 is shown in detail in Fig. 14 and generally indicated therein at
77. The coupler 144 transmits rotary motion from the speed changing
apparatus 92 to the rotary tool 96.
The electrical system of the dental instrument 12 is shown in the
schematic diagram in Fig. 8 and includes a set of contacts to electrically
connect the control switch 134 on the mount 94 with the motor 98 and
battery 100. The structure of the set of contacts includes a contact support
block 146 secured to the end of the hand-piece enclosure end 108 adjacent
to the base 120, a set of contacts 148 and 150 on the upper portion of the
block 146, and a cooperatlng palr of contacts 152 and 154 secured to the
outer flange-like expanded portion 130 of the removable mount portion 119.
The control switch 134 is mounted in the wall of the upper mount portion 132
with a button 135 on the exterior of the outer surface. The wires from the
control switch 134 are located in the removable portion of the mount 128 as
shown in ~ig. 5. When the removable portion of the mount is screwed onto
the mount base 120 the contacts 152 and 154 are brought into cooperating
contact with the contacts 148 and 150 on the mount block 146. Referring to
the schematic diagram of ~ig. 8 the switches 103 and 134 are in a parallel
relation so closing of either of the switches will operate the motor 98. The
motor 98, the battery 100 and induction coil recharging apparatus 102 are
preferably similar to that hereinbefore described being in conjunction with
the first embodiment, (1), and functionally operate the same. It is to be
-14-
1036~45
ul.~erstood that the speed changing apparatus ~2 shown in Fig. 5 is a
speed reducing apparatus that can be constructed with the pulleys thereof
sized so as to provide a speed increase, if desired, for the output shaft
relative to the motor shaft.
In practice and in use of this dental instrument 12, it has been
found that the second control switch 134 on the mount 94 is a useful and
conven~ent feature. A structure of the mount 94 is sized such that it can
be comfortably grasped by the fingers with the hand-piece 90 resting on the
portion of the hand between the thumb and forefinger with the push-button
135 on the second control switch 134 operated by the thumb or the forefinger.
The structure of the hand-piece 90 is such that the control switch 103 can
be operated with a thumb or a finger with the hand-piece positioned generally
between the thumb and the fingers and used similar to the dental instrument
lO of the first described embodiment, (1).
Another embodiment, (3), of the dental instrument of this invention
is shown on Sheet 2 of the drawings in Figs. 9, 10 and 11 and generally
lndlcated at 14 therein. The dental instrument 14 includes a handle or hand-
p{ece 160 with a speed changing apparatus 162 in a hollow portion thereof,
a chuck or mount 164 on the end portion of the handle or hand-piece 160 to
removably mount a rotary dental tool 166. The rotary dental tool 166 shown
in ~ig. 9 has a contra angle drill tool mounted thereon which is illustrative
of the types of rotary dental tools usable with the dental instrument 14 and
the other embodiments of the dental instrument of this invention. The hand-
piece or handle 1~0 is an enclosure as shown in E~igs. 9, 10 and 11 and
encloses a battery having a pair of cells 170 and 172 shown in dashed lines,
a motor 174 and a battery recharging apparatus 176. The end of the handle
or hand-piece 160 which encloses the speed changing apparatus 162 is a
hollow enclosure portion with an end member 178 to which a portion of the
chuck or mount 164 is secured. The shape of the hand-piece enclosure 168
can be seen in the combination of the views of the dental instrument 14 shown
- 15-
~`` 10:~6845
,- ~igs. 9, 10 and 11 as generally corresponding to the cylindrical shape
of the battery cells 170 and 172 and the motor 174.
The mount or chuck portion of the dental instrurr.ent indicated at
164 has a stationary base portion secured to the handle or hand-piece 160
and a removable portion attachable to a rotary dental tool 166. The speed
changing apparatus 162 has a first pulley 180 secured to the output shaft
182 of the motor 174, a rotatably mounted dental instrument output shaft
184 supported in bearings 186 and 188 in the structure of the hand-piece
enclosure 168 with a second pulley 190 secured to the shaft 184 and a belt 192
therearound the pulleys. The speed changing apparatus 162 as shown has
the first pulley or drive pulley 180 larger in diameter with the second pulley
190 or the driven pulley so the rotational speed of the output shaft 184 is
greater than the rotational speed of the motor shaft 182 during operation.
It is to be noted that the speed changing apparatus 162 can be constructed
with the first pulley 180 smaller than the second pulley 190 so the rotational
speed of the output shaft 184 is slower than the rotational speed of the motor
sbaft 182.
The mount or chuck 164 of the dental instrument 14 has a base 194
secured to the handle or hand-piece end 178 with a central upwardly
extending and exteriorly threaded portion 196 therearound the output shaft
184. The removable portion of the chuck or mount 164 is indicated at 198
and includes an interiorly threaded inner member 200, a sleeve 202
expanded on its lower end portion around the inner member 200 with a
cylindrical upper portion 204, and an outer member 206 therearound the
exterior of the sleeve 202. Preferably, the outer member 206, the sleeve
202 and the inner member 200 are bonded together by an adhesive material
as a unitary structure. The inner member 200 is threadedly attachable to
the base central upright portion 196 providing for removably mounting the
mount portion 198 with the hand~piece. The rotary dental tool 166 has a
barrel portion 208 with the tool shaft 210 centrally disposed therein. The
-16-
103684S
~;~A er portion of the barrel 208 slips over the exterior of the cylindrical
sleeve 204 in an interference fit. The interference fit between the barrel
208 of the rotary dental tool 166 and the cylindrical portion 204 of the
sleeve 202 is an important feature of the chuck or mount 164 in that the
fit is sufficiently tight to hold the rotary tool 166 in a rigid poæition
relative to the chuck or mount 164 yet it's not so rigid as to prevent
rotation of the tool barrel 208 by finger pressure as desired. The particular
mounting of the rotary tool 166 enables it to be rotated about the barrel 208
on the cylindrical sleeve portion 204 to any desired position. A resilient
coupler member 212 connects the tool shaft 210 and the upper end portion
214 of the dental instrument output shaft 184. The resilient coupler member
212 is shown in detail in ~ig. ]4, generally indicated at 77 therein and
preferably the same as described hereinbefore. The upper inner portion
of the outer mount portion 206 is spaced from the cylindrical portion of
the sleeve 204 as shown.
The electrical circuit for the dental instrument 14 is substantially
the same as the electrlcal clrcuit shown in Fig. 4 wherein the battery is
connected ln series wlth a control switch and the motor and a recharging
apparatus is connected with the battery. The battery for the dental instru-
ment 14 consists of two power cells 170 and 172 connected in a series
connection. The battery recharging apparatus as indicated at 176 in l~ig.
9 is provided with a jack 216 for connecting same with an external source
of electrical power, preferably common household power of 115 volts
alternating currents. The battery recharging apparatus 176 is contained
in the hand-piece 160 and permanently connected with the battery cells
170 and 172. A plug and cord, (not shown) are used to connect the jack
216 to a source of electrical power for recharging the battery. The control
switch for the electrical circuit is preferably mounted on the side of the
hand-piece 160 and is indicated at 218 on an extended portion of the enclosure
168. Preferably, the control switch 218 is positioned such that it can be
- 17 -
~ " 1036~4S
easily contacted and pressed by the thumb or a finger when the dental
instrument 14 is held in the hand. It is to be understood that the dental
instrument 14 can be constructed with a single rechargéable battery
having multiple cells, or it can be constructed having multiple batteries
to provide the electrical power.
Another embodiment, (4), of the dental instrument of this invention
is shown on Sheet 3 of the drawings in Fig. 12 and l~ig. 13 and indicated
generally at 16 The dental instrument 16 is basically similar to the here-
inbefore described embodiments of the dental instrument of this invention
and includes a hand-piece or handle 220, a speed changing apparatus 222
and rotary dental tool chuck or mount 224. The hand-piece or handle 220
encloses the battery, the speed changing apparatus 222 and electric motor.
The speed changing apparatus 222 is contained in a hollow enclosure on one
end of the handle or hand-piece 220 and here includes a two-stage belt
driven speed changing apparatus. The mount 224 has a stationary portion
and a removable portion and is similar to the mount of the first described
embodiment, (1), and the third described embod{ment, (3). Only the
statlonary base portion of the chuck or mount 224 is shown in ~igs. 12 and
13. The removable portion of the chuck or mount 224 is the same as that
shown in Figs. 1, 2, 9 and 10 and is omitted in E~igs. 12 and 13 to more
clearly show the stationary portion of the mount.
The hand-piece or handle 220 has a handle- like enclosure 228
enclosing the direct current electrical motor and the battery and having
mounted on the exterior thereof the control switch 230. Preferably, the
hand-piece or handle 220 has a battery recharging apparatus of the induction
coil type as shown and described hereinbefore in conjunction with the first
described embodiment, (l), of the dental instrument of this invention.
Preferably, the enclosure 228 is a cross-sectional annular structure with
elongated and tapered side walls. The speed changing apparatus 222 is
mounted in a hollow enclosure end portion of the hand-piece or handle 220
-18-
~ ~` 103684S
a~d is indicated generally at 232. The hollow portion of the enclosure 232
is shown removably mounted with the handle-like portion of the hand-piece
260. The removable portion of the enclosure has lugs 234 and 236 ex-
tending therefrom which are securable with the sides of the hand-piece by
bolts or the like as shown. The hollow enclosure portion 232 has an end
portion 238 to which the mount base 240 is secured. Sides of the hollow
enclosure portion 232 enclose and support the structure of the speed changing
apparatus 222. The statlonary portion of mount 224 has a base 240 secured
to the hollow enclosure end 238 and an upwardly extending and exteriorly
10 threaded center portion used for threadedly attaching the removable portion
of the mount. The removable portion of the mount 234 being structurally
the same as the removable portion of the mount shown in Figs. 1, 2, 9, and
10.
The speed changing apparatus 222 is comprised of two connected
stages, a primary stage from the motor and a secondary stage to the dental
instrument output shaft. In the primary stage the motor output shaft 244
has a pulley 246 secured thereto, a rotatably mounted intermediate shaft
248 with a second pulley 250 secured thereto and a belt 252 therearound
the first pulley or motor rotated pulley 246 and the second pulley 250. The
20 intermediate shaft 248 is preferably mounted with substantially friction-free
bearings such as roller bearings, not shown in the drawings. The secondary
portion of the speed changing apparatus 222 has the third pulley 252 secured
to the intermediate shaft 248, a dental instrument output shaft 254 rotatably
mounted with the enclosure end 238, a fourth pulley 256 secured to the
output shaft 254 and a belt 258 therearound the third pulley 252 and the fourth
pulley 256. The primary and secondary stages of the speed changing
apparatus is so constructed that rotation of the motor output shaft 244 causes
the intermediate shaft 248 to be rotated and the dental instrument output
shaft 254 also to be rotated. Preferably, the dental instrument output shaft
30 is mounted with substantially friction-free bearings such as roller bearings,
- 19-
1036~345
t~oTishown in the drawings. The end of the dental instrument output shaft
254 extends above the mount base 240 and is indicated at 255. In the
speed changing apparatus 232 shown in ~igs. 12 and 13 the first, second,
and third pulleys 246, 250 and 252, respectively, are substantially the
same diameter and the fourth pulley 256 is substantially larger. In this
instance the speed ratio between the motor output shaft 244 and the dental
instrument output shaft 254 causes the dental instrument output shaft 254
to rotate at a slower speed than the motor shaft 244. It is to be understood
that the slzes of the several pulleys 246, 250, 252, and 256 of the speed
10 changing apparatus of this dental instrument can be varied in size to obtain
any desired speed ratio between the motor output shaft and the dental
instrument output shaft which would cause the effective speed of the dental
instrument output shaft 254 to be lesser than or greater than the speed of
the motor shaft 244. The primary and secondary portions of the speed
changlng apparatus can be fitted with pulleys of suitable selected sizes to
substantially increase or decrease the rotation ratio of the output shaft
relatlve to the ir~put shaft or motor shaft as desired by the user. The
compound type speed changlng apparatus 222 of this embodiment, (4), of
this invention by virtue of its two stages is particularly adapted for using
20 a relatively high speed motor and by selecting the size ratio of the pulleys
obtaining an extremely high operating speed or an operating speed slower
than that of the motor. Additionally, the speed changing apparatus 222 is
adapted for use with a motor of a low or nominal speed and by selecting the
size ratio of the pulleys obtaining a relatively high instrument output speed
or a relatively low instrument output speed. The compound type speed
changing apparatus of this embodiment, (4), of this invention provides a
compact speed changing apparatus capable of providing a substantial speed
ratio between the dental instrument motor and the dental instrument output
shaftO
The electrical system of the dental instrument 16 is preferably
-20-
~ 036845
si~i lar to the electrical system shown and described in conjunction with
the first embodiment, (1), of this invention and includes a motor, a battery,
and the control switch 230 connected in a series relation and having an
induction coil type recharging apparatus connected with the battery. The
schematic diagram of this preferred electrical circuit is shown in l~ig. 4.
It is to be noted that the electrical system of the dental instrument 16 can
be constructed with a battery having multiple cells of a rechargeable nature
and it can be constructed having multiple cells of a replaceable type as
previously discussed. It is also to be noted that the control switch 230
10 can be substituted for a rheostat type switch to connect a resistor or load
in the electrical circuit thereby providing for a variable speed control for
the motor.
Another embodiment, (5), of the dental instrument of this invention
is shown on Sheet 4 of the drawings, in Figs. 15-18 and generally indicated
at 18. The dental instrument 18 includes a handle or hand-piece 262 with
the speed changing apparatus 262 in a hollow end portion thereof, a chuck
or mount 264 on the end of the hand-piece 260 removably mounting a rotary
dental tool indicated at 266.
The hand-piece or handle 260 is constructed with contacts on an end
20 portion thereof and designed to fit into a recharging base or stand apparatus
268 for recharging the rechargeable batteries enclosed in the handle or hand-
piece 260. The dental instrument 18 of this embodiment, (5), is constructed
with a battery having two separate power cells connectable with the motor
individually or in series to provide a two-speed operation of the dental
instrument. Control for the dental instrument 18 is accomplished by control
switches on the rotatable dental tool mount or chuck 264. The hand-piece
or handle 260 has an enclosure encasing the motor, the battery, the speed
changing apparatus 262, and a switch which is part of the electrical circuit.
The enclosure 270 of the handle or hand-piece 260 has a hollow end portion
30 to enclose a speed changing apparatus. The enclosure has an end 272 that
-21-
1036B~S
Fo~n s a support for the dental instrument output shaft and for the fixed
or stationary portion of the mount 264.
The speed changing apparatus is enclosed in the hollow end portion
of the hand-piece 260 as shown in ~ig. 15. The speed changing apparatus
262 includes a first pulley 274 secured to the motor output shaft 276, a
rotatably mounted dental instrument output shaft 278 with a second pulley
280 secured thereto and a belt 282 therearound the first pulley 274 or drive
pulley and the second pulley 280 or driven pulley. The dental instrument
output shaft 278 is preferably supported by low friction-free bearings, one
of which ls shown and indicated at 284. The outer end of the shaft 278 is
indicated at 286 and extends above the base portion of the mount 264. The
rotatable dental tool mount 264 includes a base 288 secured to the hand-
piece enclosure end 272 and a removable portion indicated gener~lly at 292.
The base member 288 has an upwardly extended and exteriorly threaded
portion 290 therearound the dental instrument output shaft 278. The removable
portion 292 has an internally threaded inner member 294 removably engagable
with t~e upwardly extended base portion 290, a sleeve 296 expanded on the
lower portlon around the inner member 294 and an outer member 298 there-
around the sleeve 296. The sleeve 296 has an elongated cylir~rical upper
portion 300 within the upper portion of the mount outer portion 298. The
rotatable dental tool 266 has an outer barrel- like portion 302 enclosing a
shaft 304. The interior of the rotatable tool barrel 302 is sized to slip over
the cylindrical sleeve portion 300 in an interference fit. The interference
fit between the tool barrel 302 and the sleeve 300 has an important feature
of the dental instrument 18 in that it is sufficiently tight to retain the
rotatable dental tool 266; however, it is sufficiently loose to permit rotation
of the tool barrel about the sleeve 300 by finger pressure on the two exposed
portions of the dental tool 266. Preferably, there is a space between the
exterior of the dental tool barrel 302 in the interior of the mount upper
portion 398 as indicated at 306 to facilitate easy insertion of the tool into
-22-
"` " 1036~45
the mount and to provide a mount which will accommodate rotary dental
tools of varying exterior of various dimensions. With the rotatable tool
266 in place as shown in Fig. 15 a resilient coupler member 308 connects
the dental instrument output shaft on its outer end portion 287 with the
tool shaft 304. The resilient coupler member is the type of coupler member
shown in Fig. 14 and generally indicated therein at 77. The mount or
chuck 264 supports the control switches for the motor and contacts for
connecting the switches in the electrical circuit of the dental instrument.
The electrical circuit of the dental instrument 18 is shown in
Fig. 18 and includes a battery with two cells, one indicated at 310 and
one lndicated at 312. The electrical system shown is constructed to connect
the battery cell 310 to the motor 314 or in the alternative connect the battery
cells 310 and 312 in series and with the motor 314 as well as connecting
the battery cells and series for recharging thereof. A first control switch
or a low speed control switch 316 is connected between the battery 310
and the motor 314. Two pairs of contacts 318 and 320 join the switch 316
with the circuit. The contacts 318 and 320 have one contact of each set
secured to the removable mount portion 292 and the matching contact of
each set on a contact base 322 that is secured to the hand-piece enclosure 270.
20 A second control switch or high speed control switch is indicated at 324
and is connected between the second battery cell 312 and the first battery
cell 310. Two sets of pairs of contacts 326 and 328 connect the second
control switch 324 in the circuit. The contact sets 326 and 328 also have
one contact each on the mount 292 and one contact each secured to the contact
base 322. ~ig. 15 shows in detail the structure of a set of contacts which
is representative of the several sets of contacts in the electrical circuit of
this dental instrument 18. The upper contact is indicated at 331 and is
secured to the removable mount portion 292. The lower contact 330 is secured
to the contact base member 322 on the enclosure end 272. Each of the sets
30 of contacts is connected preferably by wires in the electrical circuit. Referring
036845
~o7h e schematic diagram of Fig. 18 a third switch indicated at 332 is
provided in the circuit and functions to control operation of the circuit
between a first condition allowing the motor 314 to operate and a second
condition for recharging of the battery cells. The switch 332 is a double
throw double pole switch connected as shown with the high speed control
switch 324, the battery cells and the motor 314. One side of the switch
332 bridges the high speed control switch 324; the other side of the switch
332 connects the negative pole of the battery cell 310 and the motor 314.
In a condition to running the motor 314 the switch 332 is thrown to the
right as shown in the drawing for connecting the negative pole of the battery
cell 310 and the motor 314. When set in a condition for recharging the
battery the switch 322 is thrown to the left as it appears in the drawings
bridging the high speed control switch 324 and connecting the negative pole of
the battery cell 312 with the positive pole of the battery cell 310. Connectionsfor recharging the battery are made at the positive pole of the battery cell
312 and the negative pole of the battery cell 310 as indicated. Contacts 330
and 334 and 336 are provided on the positive connection and negative
connection, respectively. The contacts 334 and 336 extend from the
enclosure end 338 on what is shown as the lower portion of the hand-piece
260. The control switch 322 is preferably mounted on a side portion of a
hand-piece 260 as shown in ~igs. 15-17. The base or recharger stand 268
is shown in Figso 16 with portions removed with the dental instrument 18
therein. The stand has a socket portion in which the hand-piece 260 is
placed in an upright position with the hand-piece end 338 being on the bottom.
A pair of contacts 340 and 342 are provided to match with and cooperatively
engage the contacts 334 and 336 on the hand-piece 260. The contacts 340
and 342 are connected to a recharger apparatus indicated at 344 for recharging
the battery of the dental instrument 18. The recharger apparatus is preferably
powerable by household power or the like and connectable thereto by an
electrical wire indicated at 346. The structure of the base or recharging
-24-
' 1036845
57~ 268 can be varied from the structure shown as desired by the user
with the important feature of the structure being a support for the hand-
piece 260 and contacts to cooperatively engage the matching contacts on the
hand-piece 260 for recharging of the battery. For recharging of the dental
instrument battery the control switch 322 must be positioned as described
to connect the cells of the battery in a series relation with the contacts
334 and 336. It is to be noted that the structure of the recharging stand 268
can be constructed so the dental instrument 18 cannot be inserted without
the switch 332 being in the proper position. The structure of the dental
instrument 18 with the contacts 334 and 336 on the bottom thereof provides
a hand-piece structure which is well suited to the drop-in type support of
the dental instrument by the base or stand 268 or a similar suitable supporting
structure. It is to be noted that once the hand-piece 260 is removed and
the control switch 332 is set for the running condition and electrical
connection between contacts 334 and 336 will not short the battery so as to
dlscharge same.
In the manufacture of the dental instrument structure of this invention,
lt is obvious that the several embodiments of the dental instrument of this
invention are adequately and properly constructed to achieve the end product.
20 The manufacture of the handle or hand-piece portions of the structure can
obviously be accomplished by processes similar to those currently used in
the art of manufacturing portable electrically powered toothbrushes as the
structures are of a generally similar nature. The speed reducing apparatus
portion of the dental instrument structure presents no difficulty in manu-
facture as the current art is well developed in the production of small belts,
pulleys, and the like as exemplified by the structure of small portable tape
recorders and the like. The mount or chuck portion of the several embodiments
of the dental instruments of this invention are constructed generally similar
and can be easily manufactured by molding techni~ues common in the art
30 of plastic and metal bonded structures. The dental instrument of this invention
-25-
`` ` 103684S
Is adapted tO use the standard size and popular construction of rotatable
dental tools such as the prophylaxis angles, drills and the like.
In the use and operation of the dental instrument of this invention
it is seen that same provides a portable power source for operating
rotatable dental tools which is superior to the prior art. The speed changing
apparatus of the dental instrument makes the best available use of the power
produced by the small direct current electric motor. The speed changing
apparatus of the dental instrument can be constructed to increase or decrease
the output speed of the dental instrument relative to the operational speed
10 of the motor thereof which is a desirable feature and which will enable a
manufacturer to produce more or less standard hand-pieces or handles
modifylng only the speed changing apparatus pulleys to produce dental instru-
ments of a high speed capability or a low speed capability without substantially
altering the manufacturing process. The several embodiments of the dental
lnstrument of this invention provide various conveniences for the dentist
which are not available on current art dental instruments. These advantages
are namely the on-off control switches on the mount portion ~f the dental
instrument and the two-speed operation capability of the dental instrument.
Positioning the control switches on the mount and on the sides of the hand-
~0 piece makes the dental instrument easy to grasp and contn31. In practice ithas been found that positioning of the control switches on the side of the hand-
piece and on the mount do not detract from the reflexes of the user in per-
forming dental operations. It is to be noted that the dental instrument of this
invention allows a dentist to assume a standing position with both feet flat
on the floor while performing dental operations and thereby allowing the
dentist to assume a more comfortable position than possible with foot switch
controlled dental instruments.
As will become apparent from the foregoing description of the
applicant's dental instrument structure, relatively inexpensive and simple
30 means are being shown to provide a portable dental instrument which is
-26-
1036~345
~iTr emely convenient to use. The dental instrument structure is simple to
use, economical to manufacture, attractive in appearance and is adapted
to use standard rotary dental tools. The dental instrument structure has
a speed changing apparatus to make the best use of available torque from
the small D. C. electric motor. The mount of the dental instrument is
adapted to removably mount conventional rotatable dental tools in a manner
whlch will allow them to be rotated by finger pressure and to operate in any
posltton of rotation about the axis of the mount.
-27-
