Dentistry – Apparatus – Having motor or means to transmit motion from motor to tool
Reexamination Certificate
2002-05-21
2004-11-23
O'Connor, Cary E. (Department: 3732)
Dentistry
Apparatus
Having motor or means to transmit motion from motor to tool
Reexamination Certificate
active
06821120
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a dental handpiece, in particular to a dental handpiece having a tool holder for detachably holding a dental treatment tool therein.
BACKGROUND OF THE INVENTION
Dental handpieces have a tool holder for detachably holding a dental treatment tool therein. Two of such conventional dental handpieces with a tool holder are exemplified in
FIGS. 6 and 8
.
FIG. 6
is a sectional view of head
10
of an angle type dental handpiece having an air turbine. The head
10
accommodates rotor axis or bur sleeve
21
, on which rotor
14
is fixed for rotatably driving the bur sleeve
21
by means of compressed air supplied from an external source. Coil spring
19
is introduced into the bur sleeve
21
and rests on a shoulder near the lower end opening
21
a
of the bur sleeve
21
. Chuck member
40
is inserted into the bur sleeve
21
and contacts the upper end of the coil spring
19
. There is a clearance between the inner surface of the bur sleeve
21
and the outer surface of the chuck member
40
, which clearance is filled with inner tube
22
inserted from the upper end of the bur sleeve
21
and threadedly fixed on the inner surface of the bur sleeve
21
. This inner tube
22
has a downwardly flared inner surface
22
a
in its lower end portion.
The chuck member
40
is shown in detail and partially exploded in FIG.
7
. The chuck member
40
has upper tubular section
45
having a uniform outer diameter along its length, flaring section
44
having a downwardly increasing outer diameter, and annular section
41
having a uniform outer diameter. The upper tubular section
45
, the flaring section
44
, and the annular section
41
are formed integrally, with circumferential grooves
42
and
47
being interposed therebetween. The flaring section
44
has three axial slits
49
arranged at angular intervals. Each of these slits
49
receives a chucking die
43
of a complementary configuration.
In the bur sleeve
21
, the chuck member
40
having the chucking dies
43
fitted in their corresponding slits
49
, is biased upwardly by the coil spring
19
, so that the outer surface of the dies
43
are contacted with the flared surface
22
a
. This flared surface
22
a
presses the dies
43
radially inwardly, so that the dies
43
press the periphery of a dental treatment tool
50
in the bur sleeve to hold the tool
50
in position.
In manufacturing the dental handpiece of the above structure, predetermined portions of the chucking member
40
should be cut away for forming the slits
49
, and the corresponding dies
43
should be produced separately from the chucking member
40
. Thus the dental handpiece of this type requires additional labor in producing separate parts and troublesome stock control of various parts. In assembling, this handpiece also requires additional labor in positioning the tiny dies
43
in the corresponding slits
49
.
A chucking system including separate chucking dies fitted in corresponding slits in a chucking member to hold a dental treatment tool with these dies, is also disclosed in U.S. Pat. No. 4,595,363 assigned to the applicant of the present application.
FIG. 8
is a sectional view of a conventional dental handpiece of a straight type, wherein spindle
72
having coupling
84
at its proximal end is rotatably driven via the coupling
84
by means of a motor unit (not shown). The spindle
72
has an axial bore
72
a
in its distal portion for receiving dental treatment tool
90
therein. A plurality of apertures
72
e
communicating with the bore
72
a
are formed through the spindle
72
at angular intervals, and receive radially slidable pins
87
therein. A tubular member
75
is fitted around the spindle
72
slidably in the axial direction, and is distally biased by coil spring
78
. The tubular member
75
has flared inner surface
75
a
in its distal portion for contact with the pins
87
.
With this structure, since the tubular member
75
is distally biased by the spring
78
, the flared surface
75
a
is brought into contact with the pins
75
a
in the spindle
72
to press the pins radially inwardly, so that the dental treatment tool
90
in the spindle
72
is held in position with these pins
75
.
The dental handpiece of this type requires, however, production of separate tinypins
87
, formation of apertures
72
e
, assembling of these parts, and stock control of various parts, which adds complexity and labor, as with the case of the handpiece of
FIGS. 6 and 7
.
SUMMARY OF THE INVENTION
The present invention aims to solve these problems in the prior art handpieces. It is therefore an object of the present invention to provide a dental handpiece, the number of which parts are minimized to eliminate problems in parts production and stock control. It is also an object of the present invention to provide a dental handpiece of which assembly is simplified compared to the prior art handpieces.
According to the present invention, there is provided a dental handpiece comprising:
a tool holder for receiving and detachably holding a dental treatment tool therein; and
a tubular compressor disposed around said tool holder, said tubular compressor having a flared inner surface along a portion of its length;
said tool holder and said tubular compressor being relatively slidable with respect to each other between a tool holding position and a tool releasing position,
wherein said tool holder has a plurality of presser tongues formed integrally with said tool holder, each of said presser tongues being partially separate from said tool holder with a slit to have a free tip and a connecting root with a reduced thickness,
wherein said flared inner surface of said tubular compressor elastically urges said tongues into pressure contact with said dental treatment tool to securely hold the tool in position, when said tool holder and said tubular compressor are in said tool holding position.
In the dental handpiece of the above structure, the presser tongues for securely holding a dental treatment tool in position are formed integrally with the tool holder simply by providing slits and reducing the thickness of the connecting root of the presser tongues. These presser tongues are elastically urged by the flared inner surface of the tubular compressor into pressure contact with the dental treatment tool, when the tool holder and the tubular compressor are in the tool holding position, to thereby securely hold the dental treatment tool in position. Thus no tiny dies or pins are required to be produced separately from the tool holder, and accordingly no assembling step of the dies or pins and the tool holder is needed. This remarkably simplifies production, stock control, and assembly of the parts, compared to the conventional dental handpiece.
In the tool holder of the above handpiece, the presser tongues may have a flared outer surface for snugly contacting with the flared inner surface of the tubular compressor.
The slits which partially separate the presser tongues from the tool holder may be of a U-shape. The tips of the presser tongues formed by the slits may be oriented in the direction of insertion of a dental treatment tool into the tool holder in use.
The tool holder may have a plurality of connecting portions also formed integrally with the tool holder, and positioned between the presser tongues in an alternate arrangement, and the outer surfaces of the connecting portions may be offset radially inwardly from the outer surfaces of the presser tongues, so that the connecting portions do not contact with the flared inner surface of the tubular compressor.
The tubular compressor may be made stationary, while the tool holder may be made slidable with respect to the tubular compressor. Alternatively, the tool holder may be made stationary, while the tubular compressor may be made slidable with respect to the tool holder.
In the former embodiment, the handpiece may have a spring for biasing the tool holder into the tool holding position, and a push button for contacting and sliding the tool holder into
Shibata Yuichi
Suzuki Tetsuji
Dergosits & Noah LLP
Nakanishi Inc.
O'Connor Cary E.
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