Coating implements with material supply – Solid material for rubbing contact or support therefor – Including holder
Reexamination Certificate
2000-08-04
2001-05-22
Walczak, David J. (Department: 3751)
Coating implements with material supply
Solid material for rubbing contact or support therefor
Including holder
C401S093000
Reexamination Certificate
active
06234697
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mechanical pencil, and in particular, to a knocking-type mechanical pencil in which a remaining or unconsumed lead portion is pressed out by a following or next lead portion, and in which the remaining lead portion can be used until its length is shortened.
2. Background Art
FIG. 9A
shows a conventional knocking-type mechanical pencil in which a remaining lead portion can be used until its length is shortened. The conventional knocking-type mechanical pencil has a cylindrical main body
1
and a lead-feeding mechanism disposed in the main body
1
. The lead-feeding mechanism comprises a lead tank
3
containing a lead
2
, a collet chuck
4
connected to the lead tank
3
, a clutch
5
for clutching the collet chuck
4
, and a spring
6
for biasing the lead tank
3
rearwardly. A mouthpiece
7
is connected to the main body
1
, and a slider
13
extends into the mouthpiece
7
. A lead-holding member
9
is disposed in the slider
13
and extends near to a front end of the slider
13
so as to hold the remaining lead portion. When a rear end portion of the lead tank
3
is knocked, since the collet chuck
4
is clutched by the clutch
5
at a lead-gripping position, the collet chuck
4
advances while gripping the lead
2
. Then, when a flange of the clutch
5
abuts on a stepped portion
8
disposed in the mouthpiece
7
, the collet chuck
4
comes out of the clutch
5
and its front end widens, whereby the lead
2
is released from gripping. At this time, the lead
2
is inserted into the lead-holding member
9
disposed in the mouthpiece
7
and is held at the advanced position by friction of the lead-holding member
9
. When the knocking is stopped, the collet chuck
4
is moved backwardly by the action of the spring
6
, and during this backward movement, the clutch
5
clutches the collet chuck
4
and the lead
2
is thereby gripped gradually. When the flange of the clutch
5
abuts on a shoulder portion
10
, the collet chuck
4
returns to the gripping position and the lead
2
can be firmly gripped. As mentioned above, since the chuck
4
grips the lead
2
on its return to the gripping position from the advanced position and the lead
2
is transferred, the lead
2
moves backwardly a little from the advanced position.
The lead-holding member
9
has a lead insertion hole
11
and is made of an elastic material, such as rubber, so that it frictionally holds the lead
2
. The lead-holding member
9
extends to near a front end in a slider
13
which is slidably fitted in a bore
12
of the mouthpiece
7
. Inside the mouthpiece, a slider-resisting member
14
is disposed in contact with the periphery of the slider
13
so that a frictional resistance larger than a frictional resistance of the lead-holding member
9
is applied to the slider
13
. By this structure, when the collet chuck
4
is moved to the advanced position by the knocking operation, the slider
13
is pushed forward and advances together with the chuck
4
. When the front end of the slider
13
abuts on the paper surface and is pressed backwardly, the slider
13
moves backwardly, but when the mechanical pencil is not used, the slider
13
will not unnecessarily protrude or retract.
During a writing operation, the lead
2
of the mechanical pencil is fed out to such an extent that the front end of the lead
2
protrudes slightly outwardly from the front end of the slider
13
. However, when the lead
2
is shortened or consumed and is no longer gripped by the collet chuck
4
, a space
15
is formed between a remaining lead portion
2
a
and a following lead portion
2
b
as shown in FIG.
9
A. Namely, as mentioned above, when the lead
2
returns from the advanced position to the gripping position by the lead-feeding mechanism, at the moment when the collet chuck
4
is engaged with the clutch
5
, the collet chuck
4
returns clamping the following lead portion
2
b
, but the remaining lead portion
2
a
remains at the advanced position, whereby the space
15
will be formed between the remaining and following lead portions
2
a
,
2
b
. Accordingly, if the writing operation is continued, the remaining lead portion
2
a
slips within the lead-holding member
9
and moves backwardly until it abuts on the following lead portion
2
b
since the movement of the lead-holding member
9
is frictionally restrained by the slider-resisting member
14
. As a result, the protruded front end of the lead
2
retracts in the distance of the space
15
(FIG.
9
B). Accordingly, there have been drawbacks that the writing operation can not be continued and further knocking of the mechanical pencil is necessary.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a knocking-type mechanical pencil wherein a remaining or unconsumed lead can be used until its length is shortened, and even if the front end of the lead is made to abut on a paper surface during a writing operation, the lead of which the tip protrudes from a front end of a slider does not retract into the slider.
It is another object of the present invention to provide a knocking-type mechanical pencil having a front end pipe disposed at a front end of a mouthpiece so that the remaining lead can be used until its length is shortened and the remaining lead does not retract into the front end pipe during a writing operation.
The foregoing and other objects of the present invention are carried out by a mechanical pencil comprising a cylindrical main body, a mouthpiece, a slider slidably fitted in the mouth piece, and a lead-feeding mechanism disposed in the cylindrical main body for gripping a lead at a lead-gripping position and for feeding the lead to an advanced position. A lead-holding member is disposed in the slider and frictionally holds the lead fed to the advanced position. A slider-resisting member is disposed in contact with the slider so that a frictional resistance larger than a frictional resistance of the lead-holding member is applied to the slider. A releasing portion for releasing the slider-resisting member brings the slider-resisting member in slight contact with or non-contact with the slider so that the frictional resistance of the slider-resisting member is smaller than the frictional resistance of the lead-holding member in a zone which corresponds to a return amount when the lead fed to the advanced position by the lead-feeding mechanism returns to the lead-gripping position.
REFERENCES:
patent: 3892495 (1975-07-01), Naruse et al.
patent: 4056325 (1977-11-01), Maruyama
patent: 4230413 (1980-10-01), Gartner
patent: 4358210 (1982-11-01), Hashimoto et al.
Kanari Hiroyuki
Kurihara Takeshi
Adams & Wilks
Micro Co., Ltd.
Walczak David J.
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