Folding knife with blade locking mechanism

[0002] This Application claims benefit of Prov. No. 60/173,233 filed Dec. 28, 1999.

[0003] The present invention relates generally to knives, and more particularly to folding knives capable of being locked in an open position. Folding knives with various types of locking mechanisms are shown in U.S. Pat. Nos. 1,189,005, 1,454,665, 4,040,181, 4,240,201, 4,274,200, 4,404,748, 4,451,982, 4,502,221, 4,670,984, 4,805,303, 4,811,486, 4,837,932, 4,974,323, 4,979,301, 5,044,079, 5,060,379, 5,111,581, 5,293,690, 5,400,509, 5,425,175, 5,461,786, 5,515,610, 5,537,750, 5,689,885, 5,692,304, 5,737,841, 5,822,866, and 5,887,347, and in British Patent No. 3,490. U.S. Pat. Nos. 1,454,665, 4,274,200, 4,451,982, 5,111,581, 5,425,175, 5,737,841, and 5,822,866 are herein incorporated by reference. These patents disclose locking mechanisms where a blade is locked or held in place using a sliding-style locking device.

[0004] The present invention is a folding knife having a blade locking mechanism movably secured to the handle, so that the locking mechanism may be moved into a locking position. In the locking position, the locking mechanism blocks a protruding member extending transversely outward from the blade surface to lock the blade in an open position. This may be accomplished by providing a movable latch on the end of the knife handle, and biasing the latch into an extended position, in which it prevents blade rotation by obstructing a post secured to the blade. The latch may be configured in an exposed location on the knife handle so that the blade may be unlocked and moved to the closed position using one hand. In addition to assisting the locking function, the post may be configured to enable easy, one-handed opening of the blade.

[0005] FIG. 1 is an isometric view of a knife according to the present invention, depicting the blade in a closed position.

[0006] FIG. 2 is an isometric view of the knife shown in FIG. 1, depicting the blade as locked in an open position.

[0007] FIG. 3 is an isometric view of the knife shown in FIG. 1, with portions of the handle cut away to show the locking mechanism used to lock the blade in the open position.

[0008] FIG. 4 is an exploded, isometric view of portions of the knife shown in FIG. 1.

[0009] FIG. 5 is a side view of the knife shown in FIG. 1, depicting the blade moving toward the open position.

[0010] FIG. 6 is a side view of the knife shown in FIG. 5, depicting the blade locked in the open position.

[0011] FIG. 7 is a side view of an alternate embodiment of a folding knife according to the present invention, depicting an alternately configured locking mechanism.

[0012] FIG. 8 is a side view of the knife shown in FIG. 7, depicting the blade locked in the open position.

[0013] FIG. 9 is a side view of another alternate embodiment of a folding knife according to the present invention, depicting a blade locking mechanism with an actuating knob that is accessible from the back of the knife handle.

[0014] FIG. 10 is an isometric view of yet another alternate embodiment of a folding knife according to the present invention, depicting a blade locking mechanism with an actuating knob that is accessible from the side of the knife handle.

[0015] FIG. 11 is an isometric view of yet another alternate embodiment of a folding knife according to the present invention, depicting an alternately configured locking mechanism that interacts with, and is accessible from opposing sides of the knife handle.

[0016] FIG. 12 is a view depicting a user's hand retracting a blade locking mechanism according to the present invention, in order to unlock the blade.

[0017] Referring to the drawings, and more specifically to FIGS. 1 and 2, a folding knife 10 according to the present invention is shown, including handle 12 and folding blade 14. Handle 12 includes a pair of side members such as sideplates 16 and 18, which are separated at back portion 20 of handle 12 by a spacer such as backstrap 22 (FIG. 4). Handle 12 defines a blade-receiving channel 24 between sideplates 16 and 18. The tang of blade 14 is pivotally attached to handle end 12aby a pintle or pivot shaft 26, enabling blade 14 to pivot about pivot axis 28 between a closed position and an open position. In the closed position, blade 14 is at least partially received within blade-receiving channel 24, as shown in FIG. 1. FIG. 2 depicts the blade in the open position, in which it extends away from handle 12.

[0018] A protruding member such as a post or thumbstud 30 may be secured to blade 14. Typically, post 30 is cylindrically shaped and extends transversely to blade 14 from one or both of the broad flat sides of the blade. When provided on both sides of the blade, post 30 may include two separate post portions (one for each side of the blade), or a single unitary post may be disposed through a hole formed in the blade. Post 30 typically is spaced from pivot axis 28, so that the post defines an arcuate path of travel P centered about the pivot axis when the blade is rotated between the open and closed positions respectively depicted in FIGS. 1 and 2. The post and blade typically are configured so that the post is exposed and accessible for at least a portion of the blade's pivotal travel between the closed and open positions. Preferably, the post is exposed through the whole range of pivotal travel, to enable a user to selectively move the blade by applying force to the post.

[0019] Post 30 performs a locking function, which will be explained in detail below, and enables a user of knife 10 to easily move the blade between the open and closed positions. Referring to FIG. 1, the exposed configuration of post 30 allows a user to perform a one-handed opening operation by simply applying an outward-directed force F to the post. When knife 10 is held with back 20 of the knife cradled in the palm of the hand, the thumb of the hand may be used to exert force F and cause the blade to rotate toward the open position shown in FIG. 2. This opening motion is also illustrated in FIG. 12. Rotating force may also be applied to thumbstud 30 to rotate the blade into the closed position.

[0020] Knife 10 also includes a locking mechanism that is movably secured to handle 12, typically near handle end 12a. The locking mechanism typically is movable between a retracted position and a locking position (also known as the extended position), in which it interacts with the protruding structure provided on the blade to lock the blade in the open position.

[0021] In the folding knife embodiment depicted in FIGS. 1 and 2, the locking mechanism includes a latch 32 movably secured to handle end 12aon one of sideplates 16 and 18. Latch 32 is movable in and out of an area partly bounded by latch recess 34 and coverplate 36, which are provided on the sideplate to which the latch is secured. Latch 32 is movable out of recess 34 into an extended or locking position, though typically the latch is at least partially retained within latch recess 34 even when in the extended position.

[0022] Latch 32 typically is configured so that, when moved into the extended position, the latch extends at least partly into path of travel P of the post 30. In this position, latch 32 obstructs movement of the post, as shown in FIG. 2, to prevent rotation of the blade and lock the blade in the open position. The latch and post preferably are configured so that the latch contacts or otherwise engages the post when the blade is in the open position. This eliminates play or wobble resulting from the blade moving slightly out of the open position.

[0023] Latch 32 may be biased toward, or into, the locking/extended position shown in FIG. 2. Typically, this is accomplished by some sort of spring assembly, such as plunger assembly 40, which is shown in FIGS. 3 and 4. Plunger assembly 40 biases latch 32 into the extended position and includes a bent wire latch spring 42 that is operatively connected between knife handle 12 and latch 32. Specifically, first end 42a(the “latch end”) of the latch spring engages latch 32 and second end 42b(the “handle end”) is received within hole 22ain backstrap 22.

[0024] Alternatively, the spring assembly may be configured with a wire plunger 44 connected to a coiled latch spring 46 that is held by the knife handle within a cavity in the backstrap, as shown in FIGS. 7 and 8. One end of wire plunger 44 contacts latch 32, while the opposite end of the plunger engages latch spring 46. Latch spring 46 resists compression to provide a biasing force that urges latch 32 into the extended locking position.

[0025] As indicated above, post 30 contacts, engages or otherwise interacts with latch 32 as blade 14 is rotated between the closed and open positions. For example, folding knife 10 typically is configured so that, during an intermediate portion of the rotational range of the blade, post 30 contacts latch 32 and forces the latch into the latch recess. This is shown in FIG. 5. It will be appreciated that the spring cavity in which the latch spring is received is sized and shaped to allow the latch spring to compress and deform when latch 32 is pushed into latch recess 34. Typically, post 30 does not force latch 32 into recess 34 when blade 14 is fully rotated into either the open or closed position.

[0026] Preferably, post 30 and latch 32 are shaped so that, when extended, the latch permits rotational movement of the blade toward the open position, but does not permit rotation out of the open position. This typically is achieved by providing the outer portion of the latch with a cam-like profile that enables post 30 to “ride” onto latch 32 and force the latch downward into recess 34 when the blade is rotated from the closed position toward the open position.

[0027] By contrast, when the blade is in the open position, the extended latch presents a planar blocking surface to post 30 that is perpendicular to travel path P of the post. Therefore, the blade cannot be rotated out of the open position unless the latch is retracted from the extended position. As explained below, various alternatives exist for operating latch 32 and causing it to be retracted when the blade is to be unlocked and folded into the closed position.

[0028] In the embodiment shown in FIGS. 1-5, the latch moves in and out of the latch recess translationally, however the latch may be configured to pivot into and out of the latch recess. FIGS. 7 and 8 depict such a pivoting latch 50. FIG. 7 depicts latch 50 in both the retracted position (solid lines) and the extended position (dashed lines), while FIG. 8 depicts latch 50 in the extended locking position only. Latch 50 is secured to handle sideplate 16 using pivot pin 52, enabling the latch to pivot outward into the extended locking position shown in FIG. 8. In the extended position, the latch is still partially received within latch recess 34. As with the previously described latch configurations, latch 50 may be biased into the extended position using a spring or other biasing mechanism.

[0029] As indicated above, the blade may be provided with a post that extends from both sides of the blade. The locking mechanism of the present invention may similarly be configured for operation on both sides of the blade. For example, latch 32 (FIGS. 1 and 2) may be modified in order to engage a thumb/locking post having portions extending from both sides of blade 14. FIG. 11 depicts such an alternately configured latch 60. Latch 60 includes all of the structural components of latch 32, but with various of those components duplicated on the other side of knife handle 12, including a latch recess, coverplate, and cam-like member configured to move into and out of the latch recess. In addition, a second biasing assembly may be provided to assist in biasing the entire latch assembly toward the extended/locking position. An advantage of the two-sided approach is that the design is symmetrical with respect to both sides of knife handle 12, enabling either right- or left-handed operation of the thumb post and locking mechanism.

[0030] The locking latches described above are exposed to enable manual retraction of the latch with a user's thumb. For example, FIG. 12 depicts a user's hand 61 retracting the locking latch (not shown) to unlock blade 14 and fold it toward the closed position. Alternatively, a manual actuating mechanism may be operatively connected to the latch such that selectively operating the actuating mechanism causes the latch to be retracted from the extended locking position. For example, referring now to FIG. 9, knob 62 is operatively connected to latch 32 through a slot in back 20 of handle 12. Alternatively, an actuating knob 64 may be provided to extend out of a slot in the side of the knife handle, as shown in FIG. 10.

[0031] In addition to the various features discussed above, a blade spring may be provided to assist opening and/or closing of the knife blade. The blade spring is operatively connected between the blade and knife handle, and has one end secured to the blade and a second end held by a slot formed in the knife handle. Typically, the blade spring is configured to undergo maximum deformation (compression or tension) when the blade is pivoted to an equilibrium point between the open and closed positions. When the blade is pivoted to one side of the equilibrium point, the blade spring exerts a closing force upon the blade to urge it toward the closed position. On the other side of the equilibrium point, the spring exerts an opening force upon the blade.

[0032] Although the invention has been disclosed in its preferred forms, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense, because numerous variations are possible. The subject matter of the invention includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions, and/or properties disclosed herein. No single feature, function, element or property of the disclosed embodiments is essential. The following claims define certain combinations and subcombinations of features, functions, elements, and/or properties that are regarded as novel and nonobvious. Other combinations and subcombinations may be claimed through amendment of the present claims or presentation of new claims in this or a related application. Such claims, whether they are broader, narrower, equal, or different in scope to any earlier claims, also are regarded as included within the subject matter of the invention.