Cutter knife for left handed and right handed persons

Cutlery – Sheathed – Sliding blade

Reexamination Certificate

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Details

C030S320000, C030S335000

Reexamination Certificate

active

06708410

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a cutter knife in which the blade is slidably retracted into an elongated sleeve member. In particular, the present invention relates to a cutter knife wherein a space is kept between the blade edge and an inner wall of the sleeve member, in order to prevent the blade edge from being damaged by rubbing against the inner wall of the sleeve member, while sliding.
FIGS. 1
to
3
B show a cutter knife, which is disclosed in Japanese examined utility model publication No. 59-20872. A blade
1
and a slider
10
are connected in an elongated sleeve member
20
. A user can manipulate the slider
10
to cause the blade
1
to slide, so that the blade
1
is protruded from and retracted into the sleeve member
20
. The sleeve member
20
is provided with a pair of side walls
20
a
and
20
b
, which extend in parallel to the sliding direction of the blade
1
. Being guided between the side walls
20
a
and
20
b
, the blade
1
and the slider
10
slide in the longitudinal direction of the cutter knife.
As shown in
FIG. 2
, a spring member
11
is provided on one side of the slider
10
. Under the biasing force by the spring member
11
, the blade back
1
b
is pressed onto the inner surface of the side wall
20
a
(the side wall at the upper location in FIG.
1
). As a result, a space is kept between the blade edge
1
a
and the inner surface of the side wall
20
b
(the side wall at the lower location in FIG.
1
). Thanks to that space, the blade edge
1
a
can be prevented from rubbing against the inner surface of the side wall
20
b
, and thus the blade edge
1
a
can be protected from damage.
The slider
10
is provided with two engagement protrusions
15
,
16
, which are located at the forward end and at the rearward end of the slider
10
in the sliding direction. One of the engagement protrusions is inserted into a connection hole
2
of the blade
1
, so that the slider
10
and the blade
1
are connected. As shown inside the dash-lined frame in
FIG. 1
, when the inserting direction of the slider
10
into the sleeve member
20
is reversed, the engagement protrusion
16
is now engaged with the connection hole
2
, rather than the engagement protrusion
15
. As a result, the direction of the biasing force applied to the blade
1
by the spring member
11
is also reversed. In other words; when the inserting direction of the slider
10
is reversed, and further the blade
1
is turned so that the edge
1
a
faces upward as shown in
FIG. 1
, the blade back
1
b
is pressed onto the inner surface of the side wall
20
b
under the biasing force of the spring member
11
, As a result, a space is kept between the blade edge
1
a
and the inner surface of the side wall
20
a.
The reason why the biasing direction of the blade is reversed is for accommodating the cutter knife to both right handed users and left handed users. This is explained with reference to
FIGS. 3A and 3B
, which are partially broken end elevations seen from the user side who is grasping the cutter knife.
FIG. 3A
shows a situation where a left handed user uses the cutter knife, which corresponds to the case where the slider
10
shown inside the dash-lined frame in FIG.
1
and the blade
1
connected thereto are inserted into the sleeve member
20
. In
FIG. 3A
, the blade edge
1
a
faces downwards. The user grasps the cutter knife in his left hand, and manipulates the slider knob
18
attached to the slider
10
with his left thumb for protruding and retracting the blade
1
. The blade
1
is connected with the slider
10
at the engagement protrusion
16
, and the engagement protrusion
15
in disengagement can be seen from the user side. The slider knob
18
is in threaded engagement with a threaded hole
17
provided on the slider.
FIG. 3B
shows a situation where a right handed user uses the cutter knife, which corresponds to the case where the slider
10
and the blade
1
connected thereto are inserted into the sleeve member
20
as shown by the solid-lined arrow in FIG.
1
. Also in
FIG. 3B
, the blade edge
1
a
faces downwards. The user grasps the cutter knife in his right hand, and manipulates the slider knob
1
a
attached to the slider
10
with his right thumb for protruding and retracting the blade
1
. The blade
1
is connected with the slider
10
at the engagement protrusion
15
, and the engagement protrusion
16
in disengagement can be seen from the user side.
In the conventional cutter knife as explained above, with reversing the inserting direction of the slider, right handed users and left handed users can properly use it. However, the construction of the slider is inconveniently complicated. Specifically, in order to provide the spring member
11
constructed an shown in
FIG. 2
on the slider
10
, it is necessary to attach a separate member of a leaf spring on the slider
10
, Alternatively, even if a spring portion is integrally formed into the slider
10
, a very complicated mold would be necessary, which would increase the cost.
SUMMARY OF THE INVENTION
In view of the above-mentioned circumstance, an object of the present invention is to provide a cutter knife, which has simpler construction and can be properly used by both right handed users and left handed users.
According to the present invention, there is provided a cutter knife, comprising: an elongated sleeve member, a blade slidably held in the sleeve member, and a slider which is connected with the blade and is slidable in the sleeve member in the longitudinal direction, via which the blade is manipulated to protrude from and retracted into the sleeve member. The slider is provided with a first engagement protrusion and a second engagement protrusion located on the forward end and the rearward end in the sliding direction of the slider, one of which is to be inserted into a connection hole of the blade for connecting the slider and the blade. The distance from each of the first engagement protrusion and the second engagement protrusion to an inner surface of one of the sidewalls of the sleeve member when the slider is inserted into the sleeve member is smaller than the distance between the connection hole and the back of the blade. The back of the blade is thereby biased against the inner surface of the sleeve member to keep a space between the edge of the blade and the inner surface of the other sidewall of the sleeve member while the blade is sliding. The first engagement protrusion and the second engagement protrusion are aligned parallel to the sliding direction of the slider. Thus, when the inserting direction of the slider into the sleeve member is reversed, the biasing direction of the blade is also reversed,
In the cutter knife constructed as above, when the facing direction of the blade and inserting direction of the slider are reversed, the biasing direction of the blade against the inner surface of the sleeve member is reversed. This advantage itself can be achieved also in the above-mentioned conventional cutter knife. However, in the present invention, the biasing force is attributed to the location (or arrangement) of the engagement protrusions provided on the slider. Thus, any separate members (such as a spring member
11
) for providing the biasing force are not necessary, and thanks to this, the construction of the slider can be more simplified than in the conventional cutter knife. Accordingly, the cutter knife can be easily manufactured, leading to a lower manufacturing cost and a lower selling price.


REFERENCES:
patent: 4089112 (1978-05-01), Richards
patent: 4170062 (1979-10-01), Machida
patent: 4240202 (1980-12-01), Gilbert
patent: 4292738 (1981-10-01), Osada
patent: 5269063 (1993-12-01), Okada
patent: D398829 (1998-09-01), Okada
patent: 6006433 (1999-12-01), Baltazar
patent: 6314646 (2001-11-01), Schmidt
patent: 59-20872 (1984-06-01), None

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