Cutlery – Sheathed – Sliding blade
Reexamination Certificate
1999-06-11
2001-02-20
Watts, Douglas D. (Department: 3724)
Cutlery
Sheathed
Sliding blade
C030S002000, C030S319000
Reexamination Certificate
active
06189218
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a grip-type cutter knife wherein a knife blade is projected from a cutter body thereof by pressing a trigger lever.
FIGS. 1 and 2
show one example of a well-known conventional grip-type cutter knife
10
. This cutter knife comprises an elongated cutter body
11
provided with a grip portion
12
. At the front end of the body
11
, there is provided a circular rotary blade
15
. In
FIG. 1
, the rotary blade
15
is projected from the body for cutting. In
FIG. 2
, the rotary blade
15
is retracted in the body, and the cutting is impossible.
The rotary blade
15
is connected to a swing member which is pivotally supported in the cutter body
11
. A part of this swing member is projected from the grip portion
12
to serve as a trigger lever
14
(FIG.
2
). The swing member is forced into the non-cutting position (
FIG. 2
) by a spring member (not shown) arranged in the cutter body
11
. That is, when grasping the trigger lever
14
into the cutter body
11
against the spring force, the rotary blade
15
is projected from the forward end of the cutter body
11
(FIG.
1
). On the other hand, when releasing the grasping hand, the rotary blade
15
is retracted into a platform
13
at the forward end of the cutter body
11
.
Among the grip-type cutters, there are some products which have a cover on the platform
13
of the cutter body
11
, or which have a locking mechanism prohibiting the swing of the swing member, in order to avoid the unintentional projection of the blade. The cutter having the locking mechanism is more convenient in handling than that having the cover.
Even among the grip-type cutters having a locking mechanism, although a mechanism locking the knife blade in retracted position is known, a mechanism locking the knife blade in projected position is unknown. It is understood from
FIG. 1
that, in order to keep the knife blade projected, a user must keep on grasping the grip portion
12
against the spring force to press the trigger lever in. This would bring physical fatigue to the user in continuous working.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a grip-type cutter knife wherein a knife blade can be locked in both retracted and projected positions with a locking mechanism the construction and handling of which are both simple.
In view of the above object, the present invention provides a grip type of cutter knife comprising:
a knife blade which is projected by grasping, against spring force, a trigger lever projected from a grip portion of a cutter body; and
a push-type locking mechanism which is selectively held in an unlocking position wherein the trigger lever is allowed to swing, or a locking position wherein the swing is prohibited.
Further, the present invention provides a grip type of cutter knife comprising:
a cutter body having a grip portion;
a swing member being pivotally supported in the cutter body and carrying a knife blade, wherein one end of the swing member serves as a trigger lever;
a biasing member forcing the swing member into a non-cutting position wherein the knife blade is retracted in the cutter body and the trigger lever is outwardly projected from the grip portion of the cutter body; and
a locking member which is longer than a thickness of the cutter body and which is placed through an opening formed in the cutter body and through an elongated opening formed in the swing member, the locking member comprising a larger diameter cylindrical body and a smaller diameter portion partially formed in the cylindrical body;
wherein the opening formed in the cutter body fits a cross sectional configuration of the locking member so as to allow the locking member to slide only in the thickness direction of the cutter body;
wherein the elongated opening formed in the swing member comprises a first wider space and a second wider space with a neck portion therebetween, through which neck portion the smaller diameter portion of the locking member is able to pass, but the larger diameter cylindrical body is not able to pass, and
wherein the locking member has a holding mechanism which holds the locking member itself selectively in an unlocking position wherein the smaller diameter portion of the locking member is in a swing route of the swing member so as to allow the swing member to swing, or a locking position wherein the larger diameter cylindrical body of the locking member is in the swing route of the swing member so as to engage with the first or second wider space to prohibit the swing of the swing member.
In the cutter knife of the present invention constructed as above, the locking member longer than the thickness of the cutter body is held in the cutter body so as to slide only in the thickness direction of the cutter body, so that the locking member can be selectively placed in the “unlocking position” wherein one end of the locking member is projected from one side of the cutter body, or the “locking position” wherein the other end of the locking member is projected from the other side of the cutter body. When the locking member is placed in the “unlocking position” , the smaller diameter portion of the locking member is in the swing route of the swing member. Because the neck portion of the elongated opening formed in the swing member can pass through the smaller diameter portion, the swing member is allowed to swing. On the other hand, when the locking member is placed in the “locking position”, the larger diameter cylindrical body of the locking member is in the swing route of the swing member, and engages with the first or second wider space of the elongated opening formed in the swing member. Because the neck portion of the elongated opening formed in the swing member can not pass through the larger diameter cylindrical body, the swing of the swing member is prohibited.
The locking member is to be projected from the different side of the cutter body depending on its positioning in the “unlocking position” or in the “locking position”. Further, the locking member is provided with a holding mechanism which selectively holds the locking member itself in the “unlocking position” or the “locking position”. Therefore, the switching between the “unlocking position” and the “locking position” can be easily executed by pushing the locking member with a finger.
Further, the knife blade can also be locked in the projected position by switching the locking member from the “unlocking position” to the “locking position” when the knife blade is in the projected position (cutting position), as well as that the knife blade can be locked in the retracted position by switching the locking member from the “unlocking position” to the “locking position” when the knife blade is in the retracted position (non-cutting position). Thanks to this function, in the case of continuous working with the cutter knife for a long time, at least the “gripping force for keeping the rotary blade in the projected position” is not needed, so that the physical fatigue due to the continuous working can be lowered.
In the present invention, the holding mechanism of the locking member can be preferably constituted by a protrusion which is laterally projected from the larger diameter cylindrical body and is able to elastically retract into the larger diameter cylindrical body. This protrusion engages with an edge of the opening formed in the cutter body so as to selectively hold the locking member in the “unlocking position” or the “locking position”.
In the case this holding mechanism is employed, because of the appropriate snap fitting at the time of reaching the “unlocking position” or the “locking position” of the locking member, not only the holding of the locking member at each position is ensured, but also a sense of safety at handling is enhanced.
REFERENCES:
patent: 4541175 (1985-09-01), Boyd et al.
patent: 5101564 (1992-04-01), Melter
patent: 5299355 (1994-04-01), Boda et al.
patent: 5355588 (1994-10-01), Brandenburg
patent: 5924203 (
Evenson, McKeown, Edwards & Lenahan P.L.L.C.
Olfa Corporation
Watts Douglas D.
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