Cutlery – Sheathed – Sliding blade
Reexamination Certificate
1999-03-18
2001-05-08
Rada, Rinaldi I. (Department: 3724)
Cutlery
Sheathed
Sliding blade
C030S335000
Reexamination Certificate
active
06226873
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an automatic locking type cutter knife.
BACKGROUND OF THE INVENTION
The present invention relates to an automatic locking type cutter knife. The automatic locking type cutter knife is known to have a variety of operations and structures. The automatic locking type cutter knife, as disclosed in Examined Published Japanese Utility Model Application No. 57-54771 or 61-35177, is equipped with a stopper mounted on the back face of the center protruding portion of a retaining leaf spring for preventing the leaf spring from turning. This structure can prevent the turning of the leaf spring when the stopper is moved in one direction. When the spring is released, it is troublesome to return the stopper. When a force acts to move a slider to be coupled to a cutter blade while the slider is being retained by the stopper, the center protruding portion of the leaf spring is pushed forward or backward onto the square hole of a blade holder. As a result, the center protruding portion of the leaf spring is pushed so much between the square hole and the corrugated ridge of the knife frame that it is unusably deformed.
On the other hand, an automatic locking type cutter knife, as disclosed in Unexamined Published Japanese Patent Application No. 6-327849, employs a leaf spring having a generally triangular projecting portion for a triangular engaging groove. This structure raises a problem in the reliability of the retaining force of the cutter blade. Another problem is that the leaf spring is liable to come out from the opening of a center recess, as formed in a body member of the slider, and to be deformed.
In an automatic locking type cutter knife, as disclosed in Examined Published Japanese Patent Application No. 7-85752, a leaf spring is provided with a flat spring portion extending in the forward direction of a cutter blade, and a protruding portion having an inverted U-shaped section and protruding at a right angle with respect to the spring portion. This structure has a problem that the force to be applied by the leaf spring to an engaging groove is weak in a neutral position.
The invention has been conceived with a view to the background thus far described and has an object to provide a cutter knife which can be stepwise automatically locked while preventing the leaf spring from being unusably deformed.
SUMMARY OF THE INVENTION
According to an embodiment of the invention there is provided a cutter knife comprising: a holder having a plurality of engaging recesses of an isosceles trapezoid shape formed intermittently in its upper face to have a larger width outward and a slide groove into which a cutter blade is to be inserted movably back and forth; a slider inserted in the slide groove of said holder and formed to mount said cutter blade thereon; and a leaf spring member supported by said slider to come into and out of engagement with said engaging recesses, characterized: in that said slider includes a body member, an operation member supported movably on said body member, and a leaf spring member; in that said leaf spring member includes leg portions expanded obliquely, a protruding portion of an isosceles trapezoid formed at the center portion of said leg portions and capable of engaging with said engaging recesses, and a wide portion formed in the vicinity of the root portion of said protruding portion and made wider than said obliquely expanded leg portions; in that said body member includes a center recess, an opening formed at the center in the upper face of said center recess for allowing the protruding portion of said leaf spring to go into and out of it, and a boss positioned in the vicinity of said opening for preventing the deformation of the protruding portion of said leaf spring; and in that said operation member includes a movable stopper for engaging with said wide portion at its neutral position to prevent the protruding portion of said leaf spring from moving backward, and an engaging groove for pushing downward said protruding portion against the elasticity of said leaf spring by the moving operation of said operation member so that the protruding portion of said leaf spring may be released from said engaging recesses.
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Davis , Wright, Tremaine, LLP
Kyoto Doki, K.K..
Rada Rinaldi I.
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