Cutlery – Sheathed – Pivoted blade
Reexamination Certificate
1999-05-11
2001-07-10
Rada, Rinaldi I. (Department: 3724)
Cutlery
Sheathed
Pivoted blade
C030S160000, C030S159000
Reexamination Certificate
active
06256887
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention lies in the field of folding knives with mechanisms to secure blades in position. In particular, this invention is directed to a release mechanism for folding blades which are secured in an open position.
Lock back systems have been in use for many years. In a typical lock back folding knife, as a blade is extended or opened, a follower rides along the edge of a cam on the tang of the blade and drops into a notch complementary to the follower. A spring holds the follower in the notch and secures the blade in the open position. In order to close the blade the lock must be released. Conventional release mechanisms provide means for vertically displacing the follower out of the notch. Examples of such knives have been disclosed by Johnson in U.S. Pat. No. 4,040181 and Sawby et. al. in U.S. Pat. No. 4,240,201.
In 1884, in British patent No. 9352 for an automatic pocketknife, Haddan disclosed a mechanism for closing a pocketknife in which a follower was laterally displaced into a groove on the cam of a blade. In Haddan, the follower is part of a locking arm or spring that is under tension. The tension applies a rotational force, or torque, along the edge of the cam to automatically open the blade.
SUMMARY OF THE INVENTION
In the present invention, mechanisms that perrit the closing of a secured folding blade by displacing a torque free follower from a notch are disclosed.
The lock is released and the blade can be closed when a follower is laterally displaced from a notch into a side plate recess, a groove on the cam, or a combination of a side plate recess and a cam groove.
When a follower is displaced out of a notch and into a side plate recess, the blade can be closed. When the blade is in the closed position, the follower may remain in the recess or, in the alternative, the follower can be released from the recess into an insert or indentation, such as, for example, a kick or kickback, on the blade to secure the blade in the closed position.
When a follower is laterally displaced into a groove on a cam, the follower runs in the groove as the blade is folded to the closed position. If the groove runs the entire length of the cam, the follower remains in the groove when the knife is closed. In this instance, when the knife is opened, the follower runs in the groove and slides into the notch from the side to secure the blade in an open and secured position.
Alternatively, the depth of a cam groove tapers to the level of a ridge on the cam. In this instance, when the knife is opened, the follower runs along the ridge of the cam and drops down into a notch to secure the blade in the open position in a manner similar to a conventional lock back system.
A folding knife made in accordance with the disclosed invention comprises a blade, a first side plate, a second side plate, and a locking arm. The blade comprises a first side, a second side, a first edge and a second edge. The first edge and the second edge meet at one end of the blade and are joined together by a tang at the other end of the blade. The tang is preferably curved. The length of the blade extends from one end, such as, for example, a point, of the blade to the other end, such as, for example, a tang, of the blade. The width of the blade extends from the first edge of the blade to the second edge of the blade. The thickness of the blade is measured from the first side of the blade to the second side of the blade. The blade comprises a notch near the junction of the first edge and the tang. The notch extends from the second side of the blade through at least a portion of the thickness of the blade. Preferably, the notch extends across the entire thickness of the blade. Preferably, the blade comprises a kick near the junction of the tang and the second edge of the blade. The kick is a partial thickness inclination of the second surface of the blade toward the first surface of the blade. Optionally, the tang comprises a partial thickness groove along the second side of the blade. The first side plate comprises an inner surface and an outer surface. The inner surface of the first side plate faces the first side of the blade. The second side plate comprises an inner surface and an outer surface. The inner surface of the second side plate faces the second side of the blade. The thickness of each side plate blade is measured from the inner surface of the side plate to the outer surface of the side plate. The locking arm is attached at one end to the inner surface of a side plate. The unattached or free end of the locking arm comprises a follower. The locking arm has a spring like tension that causes the free end of the locking arm to move into the notch when the knife is in the filly open position. For example, when the locking arm is attached to the second side plate and there is no groove in the tang, the tension of the free end of the locking arm causes the free end of the locking arm to displace away from the inner surface of the second side plate and into the notch. As another example, when the locking arm is attached to the first side plate and there is a groove in the tang along the second side of the blade, the tension of the free end of the locking arm causes the free end of the locking arm to displace towards the inner surface of the first side plate and into the notch. When the blade is in the fully open position, the tension of the locking arm displaces the follower into the notch of the blade to secure the blade in the open position. Preferably, the first side plate comprises a thumb indent which extends across the thickness of the first side plate. Optionally, the first side plate comprises means, such as for example, a button, to laterally displace a locking arm. Preferably, the second side plate comprises a recess. A recess is shaped to accommodate at least part of the locking arm. In order to close the knife from its open position, the follower is laterally and completely displaced out of the notch toward the second side plate. When a recess is present in the second side plate, in order to close the knife, at least part of the locking arm, including the follower, is displaced into the recess. When a grove is present in the tang, at least part of the locking arm, including the follower, is displaced into the groove. Furthermore, if both a recess and a groove are present, part of the locking arm will be displaced into the groove and part of the locking arm will be displaced into the recess.
In a knife with a recess in one side plate, the blade notch, the locking arm follower and the side plate recess are aligned so that, when the blade is in the fully open position, the follower is laterally and reversibly displaceable between the notch and the recess. In a knife with an indentation or kickback, the tension of the locking arm causes the follower to displace into the indentation or kickback when the knife is in the fully closed position. In general, when a blade is in a fully closed position an indentation and a recess are aligned such that the follower is laterally and reversibly displaceable between the indentation and the recess.
Furthermore, in a folding knife comprising a blade, a first side plate, a second side plate, and a torque free locking arm, wherein said blade comprises a notch and a tang, said tang comprises a cam, said cam comprises a ridge and a groove, and said locking arm comprises a follower; and wherein, when said blade is in a fully open position, said follower rests in said notch whereby the manual lateral displacement of said follower from said notch into said goove permits said blade to be manually closed; and wherein, when said blade is in a fully closed position, the manual opening of said blade permits said follower to travel along said cam.
REFERENCES:
patent: 557760 (1896-04-01), Brauer
patent: 589737 (1897-09-01), Miller
patent: 2304601 (1942-12-01), Schrade
patent: 4040181 (1977-08-01), Johnson
patent: 4240201 (1980-12-01), Sawby et al.
patent: 4604803 (1986-08-01), Sawby
patent: 4811486 (1989-03-01), Cunningham
patent: 5325588 (1994-07-01
Ashley Boyer
Costa John G.
Rada Rinaldi I.
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