U.S. patent number 3,848,336 [Application Number 05/375,625] was granted by the patent office on 1974-11-19 for dental instrument.
Invention is credited to John W. Copeland.
United States Patent |
3,848,336 |
Copeland |
November 19, 1974 |
DENTAL INSTRUMENT
Abstract
A portable hand-piece dental instrument has a handle mounting a
motor and battery. A speed changer is mounted in the handle. It
removably mounts a chuck which in turn removably mounts a rotating
dental tool.
Inventors: |
Copeland; John W. (Wichita,
KS) |
Family
ID: |
23481633 |
Appl.
No.: |
05/375,625 |
Filed: |
July 2, 1973 |
Current U.S.
Class: |
433/99; 15/28;
433/110; 433/105 |
Current CPC
Class: |
A61C
17/005 (20130101) |
Current International
Class: |
A61C
17/00 (20060101); A61c 003/06 () |
Field of
Search: |
;32/59,58 ;15/28,29 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mancene; Louis G.
Assistant Examiner: Lever; J. Q.
Attorney, Agent or Firm: Widdowson; John H.
Claims
I claim:
1. A portable dental instrument, comprising:
a. a hollow handle,
b. an electric motor mounted in said handle, said electric motor
having a power output shaft,
c. means to power said electric motor mounted in said handle and
connected to said motor,
d. speed changing means mounted on said handle and connected to
said electric motor output shaft, said speed changing means, having
an output shaft, and
e. rotary dental tool mounting means for removably mounting a
rotary dental tool in operating position, mounted on said speed
changing means, and connected to said rotary dental tool when
mounted to change the operating speed of said tool relative the
operating speed of said motor, said mount means has a resilient
coupler member connectable between said output shaft and a drive
shaft of said rotary dental tool and a sleeve member slidably
engagable with said rotary dental tool and mounting said tool by
friction pressure such that said tool is rotatable on said sleeve
by finger pressure.
2. The dental instrument of claim 1, wherein:
a. said speed changing means has means to operate said rotary
dental tool at a rotating speed different from the rotating speed
of said motor output shaft,
b. said means to power has a rechargeable battery and means to
connect said battery with a battery charger means for recharging
same said battery, and
c. a motor control switch is mounted with said hand-piece and
connected with said motor and said battery.
3. A dental instrument of claim 2, wherein:
a. said speed changing means has a first pulley secured to said
motor output shaft, a second pulley secured to said output shaft
and a drive belt therearound said pulleys.
4. The dental instrument of claim 3, wherein:
a. said sleeve member is removably mountable with said handle,
b. said sleeve member is slidably engagable in an annular mount
portion of said rotary dental tool,
c. said motor is mounted in said handle in a position generally
aligning with said battery,
d. said means to connect said battery with a battery charger is an
induction coil means, and
e. said speed changing means is constructed and adapted to operate
said rotary dental tool at a rotating speed lesser than the
rotating speed of said motor, with said second pulley being larger
than said first pulley.
5. The dental instrument of claim 1, wherein:
a. said speed changing means has means to rotate said rotary dental
tool at a speed different than the rotating speed of said motor
output shaft,
b. said means to power has a rechargable battery and means to
connect said battery with a battery charger means for recharging,
and
c. said means to power has a pair of parallely connected control
switches, one switch mounted with said handle and a second switch
mounted with said rotary dental tool mount means.
6. The dental instrument of claim 5, wherein:
a. said speed changing means has a first pulley secured said motor
output shaft, a second pulley secured to said output shaft and a
drive belt therearound said pulleys,
b. said mount means has means to connect said second switch with
said motor and said battery, and
c. said mount means has a resilient coupler member connectable
between said output shaft and a drive shaft of said rotary dental
tool, and a sleeve member slidably engagable with said rotary
dental tool mounting said tool by friction pressure such that said
tool is rotatable on said sleeve by finger pressure.
7. The dental instrument of claim 6, wherein:
a. said sleeve member is removably mountable with said handle,
b. said sleeve member is of a diameter to be slidably engagable in
an annular portion of said rotary dental tool,
c. said mount means has an outer member secured to said sleeve
member and mounting said second switch,
d. said means to connect said second switch has one pair of
contacts secured to said hand-piece and a second pair of contacts
secured to said outer member, said pairs of contacts being
cooperatively engagable when said outer member is mounted with said
handle.
8. The dental instrument of claim 3, wherein:
a. said sleeve member is removably mountable with said handle,
b. said sleeve member is of a size to be slidably engagable in an
annular mount portion of said rotary dental tool,
c. said motor is mounted in said handle in a juxtapositional
relation to said battery, and
d. said output shaft is positioned with said rotatable axis thereof
in a spaced relation to said motor and generally aligning with said
battery.
9. The dental instrument of claim 8, wherein:
a. said output shaft is positioned with said rotatable axis
parallel to said motor and in the space adjacent an end portion of
said battery, and
b. said means to power has a battery recharger means mounted in
said handle connected to said battery and connectable to a source
of electrical power.
10. The dental instrument of claim 2, wherein said speed changing
means has a first pulley secured to said motor output shaft, a
rotatably mounted intermediate shaft having a second pulley and a
third pulley secured therewith, said output shaft having a forth
pulley secured therewith, a first drive belt therearound said first
pulley and said second pulley and a second drive belt around said
third pulley and said fourth pulley.
11. The dental instrument of claim 10, wherein:
a. said intermediate shaft is mounted in a spaced relation to said
motor, and
b. said output shaft is mounted in a spaced relation to said
intermediate shaft and generally aligning with said motor.
12. The dental instrument of claim 1, wherein:
a. said speed changing means has means to rotate said rotary dental
tool at a speed different than the rotating speed of said motor
output shaft,
b. said means to power has a rechargable battery and means to
connect said battery with a battery charger means for
recharging,
c. said battery has a first power cell and a second power cell,
and
d. said means to power has a first switch means connected to said
first power cell and to said motor and a second switch means
connected to said first power cell, to said second power cell and
to said motor in a series relation.
13. The dental instrument of claim 12, wherein:
a. said speed changing means has a first pulley secured to said
motor output shaft, a second pulley secured to said output shaft
and a drive belt therearound said pulleys,
b. said mount means has a resilient coupler member connectable
between said output shaft and a drive shaft of said rotary dental
tool, and a sleeve member slidably engagable with said rotary
dental tool mounting said tool by friction pressure such that said
tool is rotatable on said sleeve by finger pressure,
c. said first switch means has a first switch secured with said
mount means,
d. said second switch means has a second switch secured with said
mount means, and
e. said mount means has means to connect said first switch and said
second switch to said battery and to said motor.
14. The dental instrument of claim 13, wherein:
a. said sleeve member is removably mountable with said handle,
b. said sleeve member is slidably engagable in an annular portion
of said rotary dental tool,
c. said mount means has an outer member adjacent said sleeve member
with said first switch and said second switch secured therewith,
and
d. said means to connect said first switch and said second switch
each has a pair of contacts secured said outer member and another
portion of each contacts secured to said handle, said pairs of
contacts being cooperatively engagable when said outer member is
mounted with said handle.
15. The dental instrument of claim 1, wherein, said speed changing
means is constructed to rotate said rotary dental tool at a speed
lesser than said motor output shaft.
16. The dental instrument of claim 1, wherein, said speed changing
means is constructed to rotate said rotary dental tool at a speed
greater than said motor output shaft.
Description
BACKGROUND OF THE INVENTION
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 a 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 device 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 as well as decreasing the operating
speed of the motor and of the instrument. Reducing the speed of the
instrument by this means is not desirable because this type of
motor has inherently a relatively low torque and reducing the speed
proportionally reduces the torque more.
SUMMARY OF THE INVENTION
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 therin, a source of power mounted in the hand-piece,
a rotary dental tool mount on the hand-piece for removably mounting
a rotary dental tool or the like in an operating position and
further including a speed changing apparatus to mechanically change
the operating speed of the output shaft 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 switch on the
handle or hand-piece. In another preferred specific embodiment, a
dental instrument includes a motor and battery mounted in 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 instrument
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
structure includes a battery and a motor mounted in a handle or
hand-piece, a rotatably 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 motor to provide 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 which has a mount for a rotatable
dental tool or the like which will 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 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 two operating
speeds.
Yet, another object of this invention is to provide a dental
instrument of a portable nature to provide a rotary power for
operating 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 like which has two sets of
belts and pulleys connecting the output of a motor in the
hand-piece or handle of the instrument through an intermediate
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:
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation view of an embodiment of the dental
instrument having portions thereof cut away for clarity, with the
motor and battery portions thereof shown in dashed lines, the
instrument having a straight shank type prophylaxis head rotatable
dental tool;
FIG. 2 is a side elevation view of the dental instrument shown in
FIG. 1 with the rotatable dental tool pivoted on the mount;
FIG. 3 is a cross-sectional view of the dental instrument shown in
FIGS. 1 and 2, taken on line 3--3 of FIG. 2;
FIG. 4 is a schematic diagram of the electrical circuit of the
dental instrument shown in FIG. 1;
FIG. 5 is a side elevation view of an embodiment of the dental
instrument 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;
FIG. 6 is a side elevation view of the dental instrument shown in
FIG. 5;
FIG. 7 is a top plan view of the dental instrument shown in FIGS. 5
and 6 without a rotatable dental tool;
FIG. 8 is a schematic diagram of the electrical circuit for the
dental instrument shown in FIG. 5;
FIG. 9 is a side elevation view of an embodiment of the dental
instrument 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;
FIG. 10 is a side elevation view of the lower portion of the dental
instrument shown in FIG. 9;
FIG. 11 is a top plan view of the dental instrument shown in FIG. 9
with the upper portion of the rotatable dental tool removed;
FIG. 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;
FIG. 13 is a side elevation view of the dental instrument shown in
FIG. 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 instrument and the shaft of the rotatable dental
tool;
FIG. 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
FIG. 15 with the instrument in a stand structure having a battery
charging apparatus, with portions of the stand structure cut away
for clarity;
FIG. 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; and
FIG. 18 is a schematic diagram of the electrical circuit of the
dental instrument shown in FIG. 15.
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 limit the scope of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
The dental instrument of this invention is shown and disclosed
herein in five 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 instrument of this invention is shown on Sheet 2
of the drawings generally indicated at 14 and shwon in FIGS. 9-11.
Another embodiment, (4), of the dental instrument of this invention
is shown on Sheet 3 of the drawings, generally indicated at 16, and
shown in FIGS. 12 and 13. Another embodiment, (5), of the dental
instrument of this invention is generally indicated at 18 and 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 to 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 invention.
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 bearings 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 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 indicated 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
practice to provide output shaft rotating speeds suitable for
prophylaxis, cutting and polishing of teeth, 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
removable portion of the mount is attachable to the base 50. The
removable 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 inner threaded member
56 and is of a reduced size in a cylindrical portion 62 on its
opposite end portion. The outer member 60 surrounds a lower portion
of the sleeve 58 and on its upper portion 64 is spaced from the
cylindrical 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
structure 70 surrounding the shaft 68 with an enlarged collar 72 on
its lower portion that slides over the cylindrical portion 62 of
the sleeve 58 in an interference fit. The interference fit 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 positioned as desired by finger pressure on the collar portion
72 of the tool 24. FIG. 2 shows the prophylaxis head rotatable tool
having the cup 74 thereof rotated to a position different from that
shown in FIG. 1 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.
FIG. 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 solid 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. 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 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 stand. The induction coil battery recharging apparatus
79 is shown in a rectangle of dashed lines in FIG. 4 and
illustrates the preferred apparatus for recharging the battery. It
is to be understood that a recharging apparatus 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 switch included to
provide a variable speed control for the motor 28 without departing
from the scope of the invention.
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 shaft 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 prophylaxis are in the range of 400 revolutions per
minute to 5,000 revolutions per minute. 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 28 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
embodiments are provided with a direct current electric motor,
increasing 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 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 removing
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
and can easily be held in a person's hand. The dental instrument 10
can be grasped and operated between the thumb and the fingers
either in the palm of the hand or above the hand. Positioning 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 require quick
motions and relatively rapid reflex action on the part of the
dentist.
Another embodiment, (2), of the dental instrument of this invention
is indicated at 12 and is shown on Sheet 2 of the drawings in FIGS.
5-8 thereof. The dental instrument 12 of this embodiment of this
invention is basically similar to the hereinbefore described first
embodiment, (1), of the dental instrument of this invention and
further includes a second control switch 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 interior 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 switch 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 which encloses a motor 98, a battery 100 and preferably an
induction coil recharging device 102 as illustrated in the
schematic diagram in FIG. 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 are
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 extending and 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 base 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 its 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 centrally disposed therein, with the
barrel 138 being 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 instrument 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 portion 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
cooperating pair 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 FIG. 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 FIG. 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
understood that the speed changing apparatus 92 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 convenient 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 10 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 indicated at 14 therein. The dental instrument 14
includes a handle or hand-piece 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 FIG. 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 160 is an enclosure as shown in
FIGS. 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 in FIGS. 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 instrument 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 shaft 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 lower 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 position
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 FIG. 14, 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 electrical circuit shown in FIG. 4
wherein the battery is connected in series with a control switch
and the motor and a recharging apparatus is connected with the
battery. The battery for the dental instrument 14 consists of two
power cells 170 and 172 connected in a series connection. The
battery recharging apparatus as indicated at 176 in FIG. 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 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
rechargeable 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 FIG. 13 and
indicated generally at 16. The dental instrument 16 is basically
similar to the hereinbefore 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 embodiment, (3).
Only the stationary base portion of the chuck or mount 224 is shown
in FIGS. 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
FIGS. 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,
(1), 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
and 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 extending 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 stationary portion of mount 224 has a base 240
secured to the hollow enclosure end 238 and an upwardly extending
and exteriorly 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 224 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 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 a 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 is mounted with substantially
friction-free bearings such as roller bearings, not shown 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 FIGS. 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 sizes of the
several pulleys 246, 250, 252, and 256 of the speed 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 changing apparatus can be fitted
with pulleys of suitable selected sizes to substantially increase
or decrease the rotation ratio of the output shaft relative to the
input shaft or motor shaft as desired by the user. The compound
type speed changing apparatus 222 of this embodiment, (4), of this
invention by virtue of its two stages is particularly adapted for
using 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 shaft.
The electrical system of the dental instrument 16 is preferably
similar 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 FIG. 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 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
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 to enclose a speed changing apparatus.
The enclosure has an end 272 that forms 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 FIG. 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
is 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 generally 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 the
upwardly extended base portion 290, a sleeve 296 expanded on the
lower portion around the inner member 294 and an outer member 298
therearound the sleeve 296. The sleeve 296 has an elongated
cylindrical 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 faciliate easy insertion of the
tool into 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 lof 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 indicated 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. 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.
FIG. 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 of contacts is connected
preferably by wires in the electrical circuit. Referring to the
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. Connections for 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 FIGS. 15-17. The base or recharger stand 268 is shown in FIGS.
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 stand 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 discharge same.
In the manufacture of the dental instrument structure of this
invention, it is obvious that the several embodiments of the dental
instrument of this invention are adequately and properly
constructed to achieve the end product. 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 manufacture 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
techniques common in the art of plastic and metal bonded
structures. The dental instrument of this invention 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 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 modifying only the speed changing apparatus pulleys to
produce dental instruments of a high speed capability or a low
speed capability without substantially altering the manufacturing
process. The several embodiments of the dental instrument 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 of 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-piece makes the dental instrument easy
to grasp and control. In practice it has 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
performing 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 means are being shown to provide a portable dental
instrument which is extremely 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
which will allow them to be rotated by finger pressure and to
operate in any position of rotation about the axis of the
mount.
While the invention has been described in conjunction with the
preferred specific embodiments thereof, it will be understood that
this description is intended to illustrate and not to limit the
scope of the invention, which is defined by the following
claims.
* * * * *