Cutlery – Sheathed – Pivoted blade
Reexamination Certificate
2000-06-05
2001-10-23
Watts, Douglas D. (Department: 3724)
Cutlery
Sheathed
Pivoted blade
C030S160000
Reexamination Certificate
active
06305085
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a clasp knife.
BACKGROUND OF THE INVENTION
A standard clasp knife comprises a generally planar blade pivoted on an elongated handle between an open or extended position with the plane of the blade and the longitudinal axis of the handle aligned or coinciding and a folded or closed position with the blade recessed in a pocket formed in the handle. In U.S. Pat. No. 4,083,110 of Goldin the handle is basically U-shaped and the blade pivots about an axis lying in the plane of the blade. When folded the blade is surrounded by the U-shaped handle. When extended there is, however, no system for holding the blade in place so that this knife is quite difficult and even dangerous to use.
U.S. Pat. No. 4,947,551 of Deisch pivots similarly but a catch is provided to hold the blade in the extended position. While this structure is quite a bit safer than the Goldin system, the knife is quite complex. It is therefore expensive to manufacture and is fairly bulky even when folded up. Operating the catch takes two hands, making the device inconvenient to use.
While the knife of U.S. Pat. No. 4,536,959 of Ross has a catch and is of fairly simple construction, the system for holding the blade in the extended position is not very reliable. It relies on the user tightly gripping the handle in a certain way to maintain the blade lock. It is relatively easy to inadvertently release the blade so that this system is also fairly dangerous to use.
U.S. Pat. No. 5,953,821 of Mearns works like the Goldin system with a U-shaped handle. The catch is fairly weak in this system so that the blade can be easily unlatched. In U.S. Pat. No. 2,174,947 of Barsby another such system is shown where the catch is also quite weak and could release the blade or, at the very least, allow it to wobble while cutting.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide an improved clasp knife.
Another object is the provision of such an improved clasp knife which overcomes the above-given disadvantages, that is which is of simple and inexpensive construction, which can be operated with one hand, and which securely locks the blade in the extended position.
SUMMARY OF THE INVENTION
A clasp knife has according to the invention a handle lying generally in a plane and forming an elongated recess extending longitudinally in the plane, open laterally of the plane, and having an outer longitudinally open end formed with a retaining formation. A pivot pin at the outer end defines an axis substantially parallel to the plane and transverse to the recess. A blade lying generally in a plane including the axis has a cutting edge extending generally perpendicular to the axis adjacent the axis, pivots on the pin about the axis between a closed position received in the recess and an extended position with the blade plane generally coplanar with the handle plane, moves limitedly axially relative to the handle between a pair of end positions, and has a formation fitting complementary with the handle formation in one of the end positions. A spring braced axially between the blade and the body urges the blade into the one end position. A catch element is displaceable between a holding position engaging the blade in the extended position thereof and retaining the blade in the extended position and a releasing position out of engagement with the blade.
Thus this knife is of extremely simple construction, yet the blade is positively retained in the extended position. In this extended position the blade complementarily interfits with the handle so it can be used to cut and pry without moving relative to the handle.
The blade and handle are formed offset from the axis with an axially directed bump and recess that fit together when the blade is in the closed position. Thus the blade is also retained positively in the closed or closed position.
The spring according to the invention urges the bump and recess into engagement with each other in the closed position. In addition the blade is symmetrical to a longitudinally extending line perpendicular to the axis and is formed to each side of the line with one such handle formation. The blade is reversible on the pin to engage either of the handle formations so that the knife can be made right- or left-handed.
An elastic clip carries the catch element. This catch element is a pin carried on the clip and extending substantially perpendicular to the handle plane. It fits in a rearwardly open notch in the blade so that, when the pin is engaged in the notch, the blade cannot move axially on the pin and the blade and handle formations are retained together. The clip must be pulled outward to disengage the catch pin from the notch at the rear end of the blade, something that cannot normally happen when the handle is being grasped as the knife is being used, making it impossible for the knife to fold up when in use.
REFERENCES:
patent: 701686 (1902-03-01), Day
patent: 4083110 (1978-04-01), Goldin et al.
patent: 4536959 (1985-08-01), Ross
patent: 4947551 (1990-08-01), Deisch
patent: 5953821 (1999-09-01), Mearns
patent: 2 174 947 (1986-11-01), None
Stallegger Harald
Stinner Sami
Dubno Herbert
Watts Douglas D.
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