Side-knock type mechanical pencil

Details Side-knock type mechanical pencil Side-knock type mechanical pencil

2000-02-08

2001-03-20

Huson, Gregory L. (Department: 3751)

Coating implements with material supply

Solid material for rubbing contact or support therefor

Including means to advance material

C401S067000, C401S092000, C401S093000, C401S094000

Reexamination Certificate

active

06203226

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mechanical pencil in which a knock-lever mounted in a side wall of a barrel of the mechanical pencil having a chuck mechanism is knocked by a fingertip holding the barrel to draw out lead.
2. Description of the Prior art
FIG. 1
is a longitudinal sectional view showing a conventional side-knock type mechanical pencil. In this drawing, a barrel
11
is provided in the side wall thereof with an opening comprising a first opening portion
13
a
and a second opening portion
13
b
which are continuous through a fulcrum
12
formed at a contact position of a fingertip portion holding the barrel
11
during writing.
A knock lever
14
is mounted in the opening portions
13
a
and
13
b
. As shown in
FIG. 2
, the knock lever
14
is provided with a knock surface
15
knocked by a fingertip in order to draw out lead, a locking stepped surface
17
continuous to the knock surface
15
and in contact with a stepped surface wall
16
of the barrel
11
at the end of the second opening portion
13
b
to prevent the knock lever
14
from moving backward, a locking surface
18
continuous to the stepped surface
17
and in contact with an inner wall of the barrel
11
and a pair of acting flaps
24
inserted into the barrel
11
, ends of which come in contact with an inclined surface
22
of a slider
21
provided on a joint
20
, each of the acting flaps
24
being provided with a laterally projecting protrusion
26
to be locked at a locking stepped portion provided axially of the inner wall of the barrel
11
.
The knock lever
14
is provided so that the locking surface
18
is inserted into the second opening portion
13
b
, and the locking stepped surface
17
is placed in contact with the stepped surface wall
16
, the acting flaps
24
being pressed inward by a finger to press the knock surface
15
in an axial direction of the barrel
11
in a curved state, whereby the flange
26
is locked at the locking stepped portion.
The operation for drawing out lead in the prior art will be described hereinafter. The knock surface
15
is knocked whereby the acting flaps
24
come in contact with the inclined surface
22
of the slider
21
provided on the joint
20
, the joint
20
is moved forward along the inner surface of the barrel
11
against a spring
23
to open the chuck mechanism
19
to enable drawing-out of lead.
Since the conventional side-knock type mechanical pencil is constructed as described above, mounting of the knock lever on the barrel is troublesome and requires skill. Further, since the knock lever is pressed in its extreme end portion into the barrel, and the inclined surface of the rear end portion of the slider is pushed by the extreme end portion to advance the slider, it was difficult to take a knock stroke sufficiently. As a result, the opening and closing operation of the chuck mechanism is possibly unreliable. Furthermore, since the knock lever causes the slider to operate directly by the pressing force thereof, the fingertip needs to have great force. In particular, in case of a slide type mechanical pencil of a pipe provided in a tip slide, that is, a tip member, the stroke for pushing out the pipe is necessary, which had been very inconvenient in a so-called inclined surface system making use of an inclined surface portion in prior art.
This invention has been accomplished in order to solve the problem as described above. It is an object of the invention to provide a side-knock type mechanical pencil which is easy in mounting a knock lever on a barrel, and which can take a large knock stroke with small operating force.
SUMMARY OF THE INVENTION
According to this invention, there is provided a side-knock type mechanical pencil comprising a barrel having an opening in a side wall, a chuck mechanism housed in the forepart of the barrel, a slider slidably moved within the barrel to open and close the chuck mechanism, a knock lever which is inserted into the opening and pivotally mounted with respect to the barrel with an upper front end thereof acting as a fulcrum, a lower front end thereof being able to come in contact with the slider, and a resilient member for holding the knock lever in an initial position.
Further, in the side-knock type mechanical pencil according to this invention, a part of the knock lever is projected outside the barrel in the aforesaid initial position.
Furthermore, the resilient member in the side-knock type mechanical pencil according to this invention holds the knock lever in the initial position through the slider.
Further, in the side-knock type mechanical pencil according to this invention, a spherical protrusion is formed at the lower front end of the knock lever in contact with the slider.


REFERENCES:
patent: 3813176 (1974-05-01), Kamo
patent: 3836264 (1974-09-01), Saito et al.
patent: 3854824 (1974-12-01), Kamo
patent: 3883253 (1975-05-01), Naruse et al.
patent: 3892495 (1975-07-01), Naruse et al.
patent: 4627756 (1986-12-01), Kageyama
patent: 4955739 (1990-09-01), Kageyama et al.

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