Fixed-blade knife with pivotable side pieces
A fixed-blade knife includes a unitary blade having an implement, a tang, and a pivot region between the implement and the tang. The unitary blade is disposed between a pair of parallel and spaced-apart side pieces that pivot to cover or expose the implement. In the pivoted position wherein the implement is exposed, the side pieces form part of the handle that is used to grasp the knife. A locking structure locks the side pieces in a selectable position, and a limit structure prevents overrotation of the side pieces.
1 . A fixed-blade knife having a pivotable handle structure, the knife comprising:
a unitary blade having an implement, a tang, and a pivot region between the implement and the tang, wherein the unitary blade lies in a blade plane and wherein said tang further comprises a tang implement;
a pair of parallel and spaced-apart side pieces having the unitary blade disposed therebetween, wherein the side pieces are pivotable relative to the unitary blade about a pivot axis that is perpendicular to the blade plane; and
a side-piece locking mechanism that releasably locks the side pieces in at least one pivoted position.
2 . The fixed-blade knife of claim 1 , wherein the side-piece locking mechanism locks the side pieces in a first pivoted position wherein the side pieces overlie the tang, and also locks the side pieces in a second pivoted position wherein the side pieces overlie the implement of said blade.
3 . The fixed-blade knife of claim 1 , wherein said unitary blade comprises:
a blade pivot bore through the pivot region,
a locking slot through the pivot region, wherein the locking slot comprises a locking-slot angular segment of constant radius centered on the blade pivot bore, and
an enlarged locking-slot bore at an end of the locking slot.
4 . The fixed-blade knife of claim 3 , wherein each side piece comprises:
a handle pivot bore aligned with the blade pivot bore, and
the fixed-blade knife further comprises a pivot pin extending through the handle pivot bore of each side piece and the blade pivot bore and lying on a pivot axis.
5 . The fixed-blade knife of claim 4 , wherein the side-piece locking mechanism comprises
a lock-access opening extending through the first side piece and aligned with the locking slot,
a recess in the second side piece aligned with the lock-access opening and lying parallel to the pivot axis,
a locking button received through the lock-access opening and the locking slot, received in the recess, and lying parallel to the pivot axis, wherein the locking button comprises:
a head sized to be accessible through the lock-access opening,
a base sized to be slidably received in the recess,
a locking wedge extending from the base toward the head, wherein the locking wedge is too large to fit through the locking slot but does fit into and engage a side of the enlarged locking-slot bore when it is aligned with the recess,
a shank connecting the head and the locking wedge, wherein the shank is sized to fit through the locking slot, and
a biasing structure which biases the locking button toward the first side piece.
6 . The fixed-blade knife of claim 1 , wherein the unitary blade is elongated in a direction of elongation, and wherein a length of the tang measured parallel to the direction of elongation is at least about one-fourth of the length of the unitary blade measured parallel to the direction of elongation, but in no event less than about 1¼ inches.
7 . The fixed-blade knife of claim 1 , wherein said tang has a tang implement thereon that is exposed when the side pieces are pivoted away from the tang.
8 . A fixed-blade knife having a pivotable handle structure, the knife comprising:
a unitary blade further comprising an implement, a tang, and a pivot region between the implement and the tang, and wherein said tang further comprises a tang implement, the unitary blade comprising:
a blade pivot bore through the pivot region,
a locking slot through the pivot region, wherein the locking slot comprises a locking-slot angular segment of constant radius centered on the blade pivot bore, and
an enlarged locking-slot bore at an end of the locking slot;
a pair of parallel and spaced-apart side pieces having the unitary blade disposed therebetween, the pair of side pieces including a first side piece and a second side piece, wherein each side piece comprising:
a handle pivot bore aligned with the blade pivot bore,
a pivot pin extending through the handle pivot bore of each side piece and the blade pivot bore and lying on a pivot axis; and
a side-piece locking mechanism comprising
a lock-access opening extending through the first side piece and aligned with the locking slot,
a recess in the second side piece aligned with the lock-access opening and lying parallel to the pivot axis,
a locking button received through the lock-access opening and the locking slot, received in the recess, and lying parallel to the pivot axis, wherein the locking button comprising:
a head sized to be accessible through the lock-access opening,
a base sized to be slidably received in the recess,
a locking wedge extending from the base toward the head, wherein the locking wedge is too large to fit through the locking slot but does fit into and engage a side of the enlarged locking-slot bore when it is aligned with the recess,
a shank connecting the head and the locking wedge, wherein the shank is sized to fit through the locking slot, and
a biasing structure which biases the locking button toward the first side piece.
9 . The fixed-blade knife of claim 8 , wherein the implement of said blade includes a cutting edge.
10 . The fixed-blade knife of claim 8 , wherein the locking-slot segment is a semicircle.
11 . The fixed-blade knife of claim 8 , further comprising:
fasteners extending between the side pieces to hold the side pieces in the parallel and spaced-apart orientation, wherein the fasteners are positioned so as not to interfere with pivoting of the side pieces between a closed position and an open position.
12 . The fixed-blade knife of claim 8 , wherein the locking button is cylindrically symmetric about a button axis.
13 . The fixed-blade knife of claim 8 , further comprising:
a limit structure that prevents overrotation of the side pieces past a position corresponding to the alignment of the locking button with the enlarged locking-slot bore.
14 . The fixed-blade knife of claim 8 , wherein the biasing structure comprises a spring reacting between the second side piece and the locking button.
15 . The fixed-blade knife of claim 8 , further including a second enlarged locking-slot bore positioned at an opposite end of the locking slot from the enlarged locking-slot bore.
16 . The fixed-blade knife of claim 8 , further comprising:
a second enlarged locking-slot bore positioned at an opposite end of the locking slot from the enlarged locking-slot bore, and
a limit structure that prevents overrotation of the unitary blade past a position corresponding to the alignment of the locking button with the enlarged locking-slot bore and past a position corresponding to the alignment of the locking button with the second enlarged locking-slot bore.
17 . The fixed-blade knife of claim 8 , wherein the unitary blade is elongated in a direction of elongation, and wherein a length of the tang measured parallel to the direction of elongation is at least about one-fourth of the length of the unitary blade measured parallel to the direction of elongation, but in no event less than about 1¼ inches.
18 . The fixed-blade knife of claim 8 , wherein the tang implement of said tang is exposed when the side pieces are pivoted away from the tang.
19 . A fixed-blade knife comprising:
a unitary blade having an implement, a tang, and a pivot region between the implement and the tang, and wherein said tang further comprises a tang implement, the unitary blade comprising:
a blade pivot bore through the pivot region,
a locking slot through the pivot region, wherein the locking slot comprises a locking-slot angular segment of constant radius centered on the blade pivot bore,
an enlarged locking-slot bore at an end of the locking slot, and
a limit pin extending outwardly from a side of the unitary blade;
a pair of parallel and spaced-apart side pieces having the unitary blade disposed therebetween, the pair of side pieces including a first side piece and a second side piece, wherein each side piece comprising:
a handle pivot bore aligned with the blade pivot bore,
a limit slot in at least one of the side pieces, wherein the limit slot comprises a limit-slot angular segment of constant radius centered on the blade pivot bore, and wherein the limit pin of the unitary blade engages the limit slot;
a pivot pin extending through the handle pivot bore of each side piece and the blade pivot bore and lying on a pivot axis; and
a side-piece locking mechanism comprising
a lock-access opening extending through the first side piece and aligned with the locking slot,
a recess in the second side piece aligned with the lock-access opening and lying parallel to the pivot axis,
a locking button received through the lock-access opening and the locking slot, received in the recess, and lying parallel to the pivot axis, wherein the locking button comprising:
a head sized to be accessible through the lock-access opening,
a base sized to be slidably received in the recess,
a locking wedge extending from the base toward the head, wherein the locking wedge is too large to fit through the locking slot but does fit into and engage a side of the enlarged locking-slot bore when it is aligned with the recess,
a shank connecting the head and the locking wedge, wherein the shank is sized to fit through the locking slot, and
a spring bore within the base and extending parallel to the pivot axis; and
a spring lying within the spring bore and reacting to a bottom of the recess in the second side piece, the spring biasing the locking button toward the first side piece.
20 . The fixed-blade knife of claim 19 , wherein the implement of said blade includes a cutting edge.
21 . The fixed-blade knife of claim 19 , wherein the locking-slot segment is a semicircle.
22 . The fixed-blade knife of claim 19 , wherein the limit-slot segment is a semicircle.
23 . The fixed-blade knife of claim 19 , further comprising:
fasteners extending between the side pieces to hold the side pieces in the parallel and spaced-apart orientation, wherein the fasteners are positioned so as not to interfere with pivoting of the side pieces between a closed position and an open position.
24 . The fixed-blade knife of claim 19 , wherein the locking button is cylindrically symmetric about a button axis.
25 . The fixed-blade knife of claim 19 , wherein the unitary blade is elongated in a direction of elongation, and wherein a length of the tang measured parallel to the direction of elongation is at least about one-fourth of the length of the unitary blade measured parallel to the direction of elongation, but in no event less than about 1¼ inches.
26 . The fixed-blade knife of claim 19 , wherein the tang implement of said tang is exposed when the side pieces are pivoted away from said tang.