U.S. patent number 3,909,946 [Application Number 05/303,126] was granted by the patent office on 1975-10-07 for dental handpiece.
This patent grant is currently assigned to Kabushiki Kaisha Morita Seisakusho. Invention is credited to Yoshiaki Watanabe.
United States Patent |
3,909,946 |
Watanabe |
October 7, 1975 |
Dental handpiece
Abstract
A dental handpiece comprising a body portion and a forward tool
receiving end portion and detachably attached to said body portion.
The body portion has an axial bore with an axial slot in the inner
surface thereof and a lateral recess in the slot, and the forward
end portion has a shaft with an engaging pin thereon. The shaft is
inserted into the axial bore with the pin sliding in the slot, and
the shaft is turned to engage the pin in the recess for secure
connection of the two portions of the handpiece.
Inventors: |
Watanabe; Yoshiaki (Kyoto,
JA) |
Assignee: |
Kabushiki Kaisha Morita
Seisakusho (Kyoto, JA)
|
Family
ID: |
14390706 |
Appl.
No.: |
05/303,126 |
Filed: |
November 2, 1972 |
Foreign Application Priority Data
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Nov 9, 1971 [JA] |
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46-104808[U] |
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Current U.S.
Class: |
433/126 |
Current CPC
Class: |
A61C
1/18 (20130101) |
Current International
Class: |
A61C
1/08 (20060101); A61C 1/18 (20060101); A61c
001/08 () |
Field of
Search: |
;32/26,27
;285/7,317,168,308,310,314,318,317,361,396,402,403
;403/349,316,319,315 ;220/40 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mancene; Louis G.
Assistant Examiner: Lever; J. Q.
Attorney, Agent or Firm: Christensen, O'Connor, Garrison
& Havelka
Claims
What I claim is:
1. A dental handpiece comprising: a body portion and a forward end
portion detachably connected to said body portion; said body
portion being provided with an axial bore which opens at the
forward end of said body portion, an axial slot formed in the inner
surface of said bore, a lateral recess formed in said slot and a
slide key in said slot normally urged to a position to close said
recess, said slide key being normally urged by a spring to said
recess closing position and being movable out of said position
against the force of spring to a recess opening position; and said
forward end portion having means for supporting a rotary dental
tool and a shaft removably inserted into said axial bore of said
body portion and being provided with a pin slidably engageable in
said slot in said axial bore when said shaft is inserted into said
axial bore so that said pin pushes said key out of said recess
closing position and, upon relative rotation of said forward end
portion to said body portion, engages in said recess, whereupon
said key is restored to said original recess closing position and
said pin and thereby said forward end portion are securely
connected with said body portion so as to prevent relative axial
and rotative movement therebetween.
2. The handpiece of claim 1, further including a slide member
provided on the outside of said body portion and connected to said
slide key, so that when said slide member is moved, said slide key
is moved out of said recess closing position.
3. The handpiece of claim 1, wherein said axial bore of said body
portion functions as a bearing for said shaft of said forward end
portion.
4. A dental handpiece, comprising: a body portion having an axially
centered bore at the forward end thereof; detachable dental tool
supporting means including rearwardly extending shaft means on the
rear end thereof insertable into the axial bore, and means for
receiving a dental tool on the forward end thereof; transverse
extension means projecting transversely outwardly from the side of
the shaft means; means defining a slot extending lengthwise along
the interior of the axial bore; means defining a notch in
communication with the slot, the transverse extension means being
guided by the slot into the notch during insertion of the shaft
means into the axial bore; and means for preventing escape of the
transverse extension means from the notch once the shaft means are
inserted into the axial bore so as to restrain the dental tool
supporting means against rotative and axial movement relative to
the body portion, wherein the escape prevention means includes a
reciprocative member mounted for sliding movement along the
lengthwise slot between a locking position blocking passage of the
transverse extension means between the lengthwise slot and the
notch and a release position permitting passage of the transverse
extension means between the lengthwise slot and the notch.
5. The dental handpiece according to claim 4, wherein the slot
extends axially along the interior of the axial bore.
6. The dental handpiece according to claim 4, wherein the
lengthwise slot has a width representing the width of the shaft
transverse extension means, and wherein the notch is disposed
intermediate the ends of the lengthwise slot transversely to the
length thereof, the depth and width of the notch representing,
respectively, the length and width of the shaft transverse
extension means.
7. The dental handpiece according to claim 6, wherein the notch
extends depthwise circumferentially of the axial bore and widthwise
longitudinally of the axial bore.
8. The dental handpiece according to claim 4 wherein the
reciprocative member comprises a slide key mounted for sliding
movement inside the lengthwise slot.
9. The dental handpiece according to claim 8, wherein the slide key
is nestled conformably within the lengthwise slot to fair together
the interior of the axial bore and the outer surface of the slide
key, whereby unobstructed insertions of the shaft means into the
axial bore is permitted.
10. The dental handpiece according to claim 8, wherein the
lengthwise slot includes an extension portion to the rear of the
notch, the slide key in the release position thereof being slidably
mounted inside the rearward slot extension.
11. The dental handpiece according to claim 4, including means for
displaceably positioning the escape prevention means for engagement
with the transverse extension means, the escape prevention means
being temporarily displaceable by the transverse extension means so
as to permit entry of the transverse extension means from the
lengthwise slot into the notch during insertion of the shaft means
into the axial bore.
12. The dental handpiece according to claim 4, including an
operator member slidably mounted on the outer surface of the body
portion, and means for interconnecting the operator member with the
reciprocative member whereby the reciprocative member is moved
conjointly with the operator member.
13. The dental handpiece according to claim 12, including means for
normally biasing the reciprocative member to the locking position.
Description
This invention relates to a dental handpiece and more particuraly
to a mechanism for connecting the forward end portion of a dental
handpiece to the body portion thereof.
As is well known, the dental handpiece comprises a body portion
enclosing therein a micromotor or a turbine rotor and a forward end
portion detachably attached to the body portion and having a tool
at the fore end thereof. As occasions demand in treatment, various
types of forward portions are alternatively attached to the common
body portion of the handpiece. It is necessary in view of
efficiency and safety in treatment that the forward end portion of
the handpiece should remain firmly attached to the body portion and
not fall off inadvertently therefrom while in use for
treatment.
In one known type of handpiece, the forward end portion is
connected to the body portion by frictional contact. However, such
a way of connection cannot ensure 100 % firmness in connection. To
improve the firmness in connection, a screw may be used to clamp
the forward portion of the dental instrument to the body portion
thereof. With this arrangement, however, two actions are required
to connect the two portions, that is, first the forward end portion
is inserted to the body portion and then the screw must be put in
place, so that speedy operation cannot be expected.
It is one object of the invention to provide a dental handpiece
wherein firm and secure connection between the foward end and body
portions of the handpiece can be easily effected by a single action
of inserting the former into the latter portions and subsequent
relative rotation of the two portions.
The invention will be described in detail with reference to the
accompanying drawings, wherein:
FIG. 1 is a perspective view of the handpiece of the invention,
with the forward end portion thereof being disconnected from the
body portion thereof;
FIG. 2 is an enlarged perspective view in longitudinal section, of
the forward end of the body portion;
FIGS. 3a, 3b and 3c are schematic views illustrating the operation
of the connecting mechanism of the invention.
Referring to the drawings, there is shown in FIG. 1 a dental
handpiece comprising a body portion 1 and a forward end portion 2
detachably attached to the body portion in the manner to be
described later in detail. The body portion 1 encloses a
micromotor, not shown, which rotates a tool 3 detachably attached
to the tip of the forward end portion 2 when the two portions 1 and
2 are connected. The power transmission between the motor and the
tool is so well-known that it is neither shown nor requires further
explanation.
The body portion 1 is provided at its forward end with an axial
bore 11 adapted to receive the rear end of the forward end portion
2 of the handpiece in the manner to be described later. The bore 11
is provided in its inner surface with an axial slot 12 which a
slide key 13 engages. The key is rigidly connected by means of a
pin 15 to a slide member 14 provided on the outer surface of the
body portion 1. By sliding the member 14 from outside the handpiece
it is possible to move the key 13 along the slot 12 inside the
instrument body 1.
A spring 16 normally urges the member 14 and consequently the key
13 toward the forward end of the body 1. The slot 12 is provided at
a predetermined longitudinal position thereof with a lateral recess
or notch 17 extending in the circumferential direction of the bore
11. The recess 17 is normally closed by the spring-urged key 13 as
shown in FIG. 3a.
The forward end portion 2 of the handpiece has a connecting shaft
21 adapted to be inserted into the bore 11 of the body portion 1
for connection of the two portions 1 and 2. The shaft 21 has an
outer diameter a little smaller than the inner diameter of the bore
11, so that the shaft can be rotated inside the bore 11. The shaft
21 is provided on the outer surface thereof with a small engaging
pin 22 having a diameter a little smaller than the width of the
slot 12 and the recess 17, so that the pin 22 can freely move in
the slot 12 and the recess 17. The length of the recess 17 in the
circumferential direction of the bore 11 is much the same as the
diameter of the pin 22.
Without the forward end portion 2 in the bore 11, the slide key 13
is urged forwardly by the spring 16 to close the recess 17 as
previously mentioned with reference to FIG. 3a. When the forward
end portion 2 is to be connected to the body portion 1, the shaft
21 of the former portion 2 is inserted into the bore 11 of the
latter portion 1, with the pin 22 engaging in the slot 12. As the
shaft 21 is moved inwardly, the pin 22 hits against the slide key
13 in the slot 12 and pushes the key 13 against the resiliency of
the spring 16 further inwardly in the slot as far as the key 13 is
stopped by the inner end of the slot 12, where the key 13 opens the
recess 17 as shown in FIG. 3b. The length of the slide key 13 is
the same as the distance between the inner end of the slot 12 and
the inner side edge of the recess 17. Under the condition that the
key 13 opens the recess, the forward end portion 2 of the handpiece
and consequently the shaft 21 is turned in the direction as
indicated by arrows in FIG. 3b, so that the pin 22 engages in the
recess 17, whereupon the pin 22 no longer exists in the slot 12 so
that the key 13 is pushed by the spring 16 back to the original
position as shown in FIG. 3c. Now the portions 1 and 2 of the
handpiece have been connected, and with the slide key 13 confining
the pin 22 within the recess 17, no axial pulling or rotation of
the forward end portion 2 relative to the body 1 is allowed, so
that the two portions 1 and 2 are securely connected.
In order to disconnect the foward end portion 2 from the body
portion 1, the slide member 14 is simply moved toward the rear end
of the body against the force of the spring 16 so as to remove the
key 13 from in front of the recess 17 and then the forward end
portion 2 is simply turned to disengage the pin 22 from the recess
17 and then axially pulled out of the body portion 1.
Thus, in accordance with the invention, a simple action suffices to
connect the two portions of the handpiece, that is, to simply
insert the forward end portion into the body portion and turn the
two portions relative to each other. Under the connected condition,
unless the slide member 14 is moved, the two portions are never
separated, and in view of the position of the slide member 14 there
is no likelihood that the dentist handling the handpiece
inadvertently touches the slide member 14 to effect separation of
the two portions. Disconnection of the two portions when necessary
can be effected as simply and easily as the connecting operation
.
* * * * *