Low friction folding knife

Abstract

A low friction folding knife has a blade with a distal end and a tang. The tang has a slot disposed in the thickness of the tang with a roller cam extending slightly outside of the perimeter of the tang and rotatably attached within the slot. There is a handle with a first outer side parallel and attached to a first liner, a second outer side parallel and attached to a second liner. The first liner and the second liner are spaced apart and parallel leaving a blade slot for receiving the blade when the folding knife is in the closed position. The blade is pivotally coupled to the handle with a pivot bolt. There is a safety assembly disposed within the first outer handle that has a safety stud extending through a safety slot in the first outer handle for moving the safety assembly between a safe position and a safe off position. The safety assembly in the safe position lodges a steel ball through a hole in the first liner and into a ball lock hole disposed through the tang of the blade thereby preventing opening of the blade. There is an adjustable bias element disposed between the first liner and the second liner. The adjustable bias element is positioned to assist the blade in exiting the blade slot. The adjustable bias has an adjustment end and a spring distal end. The spring distal end is in spring communication with the roller cam on the tang. With the adjustable bias element adjusted to full extension, it works as an automatic opening element by maintaining contact with and applying force to the roller cam in the tang of the blade throughout the opening of the blade. With the adjustable bias element adjusted to full retraction, the folding knife is in the assisted opening mode. The user must apply pressure to the opening stud to urge the blade from the closed position. As soon as the adjustable bias element is centered with the roller cam, the blade is forced to the fully open position by the spring force of the adjustable bias element on the roller cam.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above description and other objects, advantages, and features of the present invention will be more fully understood and appreciated by reference to the specification and accompanying drawings, wherein:

FIG. 1 is an isometric view of a folding knife according to the preferred embodiment of the present invention.

FIG. 2 is an exploded view of the folding knife of FIG. 1.

FIG. 3 is an exploded isometric view of the tang portion of the knife as shown in FIG. 1 depicting the insertion of the roller cam used for assisted opening of the knife.

FIG. 4 is an isometric view of the tang portion of FIG. 1 with the roller cam inserted and pinned into position.

FIG. 5 is an exploded isometric view of the safety assembly of the preferred embodiment of the present invention.

FIG. 6 is a cross sectional view of the safety assembly of the preferred embodiment of the present invention at line 6-6 of FIG. 1 with the safety ball in the non-safe position.

FIG. 7 is cross sectional view of the safety assembly of the preferred embodiment of the present invention at line 6-6 of FIG. 1 with the safety ball in the safe position.

FIG. 8 is a detailed view of the spring adjustment feature of the preferred embodiment of the present invention.

FIG. 9 is a side view of the knife blade and roller cam with the adjustable spring withdrawn to the assisted opening position.

FIG. 10 is a side view of the knife blade and roller cam of the preferred embodiment of the present invention with the adjustable spring inserted to the automatic opening position.

FIG. 11 is an exploded isometric view of an alternate embodiment of the present invention depicting an alternate assisted opening mechanism.

FIG. 12 is an exploded isometric view of another alternate embodiment of the present invention depicting another alternate assisted opening mechanism.

FIG. 13 is a side view of the knife blade in a full open position and an alternate safety assembly in the safety on/open position of an alternate embodiment of the present invention.

FIG. 14 is a side view of the knife blade in a half closed position and the alternate safety assembly in the safety off position.

FIG. 15 is a side view of the knife blade in a closed position and the alternate safety assembly in the safety on/closed position.

Claims

1. A low friction folding knife, comprising: a blade having a distal end and a tang, the tang having a thickness with a slot disposed in the thickness, a roller cam rotatably attached in the slot by a keeper pin and extending slightly outside of the slot;a handle having a first outer handle and a second outer handle spaced apart and parallel creating a blade slot for receiving the blade when the folding knife is folded closed, the blade being pivotally attached to the handle at the tang with a pivot bolt;a safety assembly disposed within the first outer handle adjacent to the blade slot having a safety stud extending through a safety slot in the first outer handle, the safety stud enables movement of the safety assembly between a safe position and a safe off position; andan adjustable bias element disposed between the first outer handle and the second outer handle, the adjustable bias element configured to assist the folding knife to open, the adjustable bias element having an adjustment end and a spring distal end, the spring distal end is in spring communication with the roller cam on the tang, the adjustment end having a screw adjustment that extends and retracts the spring distal end;wherein, the safety assembly in the safe position forces the safety assembly against the tang of the blade preventing opening of the blade, the spring distal end of the adjustable bias element when extended applies an opening pressure to the roller cam thereby automatically opening the blade when the safety assembly is in the safe off position, the spring distal end when retracted applies a closing pressure to the roller cam holding the blade closed and assisting the blade open only after the user initiates opening by urging the blade slightly from the blade slot wherein the opening pressure replaces the closing pressure as the spring distal end moves around the roller cam, the closing pressure assists and holds the blade closed.

2. The low friction folding knife of claim 1, wherein the adjustment end of the adjustable bias element, further comprises: a receiver notch on the spring distal end;a threaded adjuster having a receiver end and a screw driver end;a threaded pillow block fixedly attached between the first liner and the second liner opposite the pivot bolt having a spring end and an open end;wherein, the threaded adjuster is screwed into the threaded pillow block and the receiver end is rotatably coupled to the receiver notch of the spring distal end such that a screw driver inserted through the open end of the threaded pillow block adjusts the threaded adjuster by engaging the screw driver end and turning clockwise, only the threaded adjuster rotates and extends the spring distal end closer to the roller cam, turning the threaded adjuster counter clockwise retracts the spring distal end.

3. The low friction folding knife of claim 1, wherein the handle further comprises a first liner parallel and attached to the first outer handle and a second liner parallel and attached to the second outer handle, the blade slot disposed between the first liner and the second liner.

4. The low friction folding knife of claim 3, wherein the safety assembly is disposed between the first outer handle and the first liner; and further comprises: a slotted ramp adjacent to the first liner, the slotted ramp having a deep ramp end and a shallow ramp end; anda safety ball;wherein, the safety ball is forced to the shallow ramp end when in the safe position thereby forcing the safety ball through a hole in the first liner and lodging the safety ball into a ball lock hole in the tang of the blade thereby locking the blade in a closed position, and in the safe off position, the safety ball is moved to the deep ramp end thereby releasing the safety ball from the ball lock hole allowing the blade to open.

5. The low friction folding knife of claim 4, wherein the safety assembly is round.

6. The low friction folding knife of claim 4, wherein the safety ball is hardened tool steel.

7. The low friction folding knife of claim 4, wherein the safety ball is ceramic.

8. The low friction folding knife of claim 1, wherein the roller cam is hardened tool steel.

9. The low friction folding knife of claim 1, wherein the roller cam is ceramic.

10. A low friction folding knife, comprising: a blade having a distal end and a tang, the tang having a thickness with a slot disposed in the thickness, a roller cam rotatably attached in the slot by a keeper pin inserted perpendicular to the slot and the roller cam extending slightly from the slot;a handle having a first outer handle parallel and attached to a first liner, a second outer handle parallel and attached to a second liner, the first liner and the second liner spaced apart and parallel creating a blade slot for receiving the blade when the folding knife is closed, the blade being pivotally coupled to the handle with a pivot bolt;a safety assembly disposed within the first outer handle and held in place by the first liner having a safety stud extending through a safety slot disposed in the first outer handle for moving the safety assembly between a safe position and a safe off position, the safety assembly in the safe position forces a safety ball through a hole in the first liner and into a ball lock hole disposed in the tang of the blade thereby preventing opening, the safety assembly in the safe off position removes force from the safety ball allowing the blade to open; andan adjustable bias element disposed between the first liner and the second liner, the adjustable bias element configured to assist the blade in exiting the blade slot, the adjustable bias element having an adjustment end and a spring distal end, the spring distal end is in spring communication with the roller cam on the tang, the adjustment end having a screw adjustment that extends and contracts the spring distal end;wherein, the spring distal end when retracted applies a closing pressure to the roller cam holding the blade closed and assisting the blade open only after the user initiates opening by urging the blade slightly from the blade slot wherein the opening pressure replaces the closing pressure as the spring distal end moves around the roller cam, the closing pressure assists and holds the blade closed.

11. The low friction folding knife of claim 10, wherein the safety ball is hardened tool steel.

12. The low friction folding knife of claim 10, wherein the safety ball is ceramic.

13. The low friction folding knife of claim 10, wherein the roller cam is hardened tool steel.

14. The low friction folding knife of claim 10, wherein the roller cam is ceramic.

15. The low friction folding knife of claim 10, wherein the safety assembly further comprises: a slotted ramp adjacent to the first liner, the slotted ramp having a deep ramp end and a shallow ramp end;wherein, the safety ball is forced to the shallow ramp end when the safety stud is moved to the safe position thereby forcing the safety ball through the hole in the first liner and lodging it into the ball lock hole in the tang of the blade thereby locking the blade closed, and when the safety stud is moved to the safe off position, the safety ball is forced to the deep ramp end thereby releasing the safety ball from the ball lock hole allowing the blade to open.

16. The low friction folding knife of claim 10, further comprising a second ball lock hole in the tang of the blade such that when the blade is fully open and the safety stud is moved to the safe position, the safety ball is forced into the shallow ramp end of the slotted ramp forcing the safety ball through the hole in the first liner and lodging it into the second ball lock hole in the tang of the blade thereby locking the blade open.

17. A low friction folding knife, comprising: a blade having a distal end and a tang, the tang having an outer edge and a finger cam extending from the outer edge, the tang having a thickness with a slot disposed in the thickness, a roller cam rotatably attached in the slot by a keeper pin inserted perpendicular to the slot and the roller cam extending slightly outside the slot;a handle having a first outer handle parallel and attached to a first liner, a spring cavity and a safety cavity extending through the first liner, a second outer handle parallel and attached to a second liner, the first liner and the second liner spaced apart and parallel creating a blade slot for receiving the blade when the folding knife is closed, the blade being pivotally coupled to the handle with a pivot bolt;a safety washer fixedly attached to the tang and adjacent to the first liner, the safety washer having a closed safety engagement notch on the perimeter;a safety assembly having a safety engagement end and disposed within the first outer handle and held in place within the safety assembly cavity in the first liner, the safety assembly having a safety stud extending through a safety slot disposed in the first outer handle for moving the safety assembly between a safe position and a safe off position; anda bias element disposed between the first liner and the second liner, the bias element having a spring distal end and a spring attach end, the spring distal end in spring communication with the roller cam on the tang, the spring attach end is fixedly attached between the first liner and the second liner;wherein, the safety assembly in the safe position forces the safety engagement end into the closed safety engagement notch on the safety washer thereby preventing opening, the safety assembly in the safe off position retracts the safety engagement end from the closed safety engagement notch allowing opening of the blade, with pressure applied to the finger cam on the tang of the blade to rotate the blade out of the blade slot, the spring distal end of the bias element applies spring force on the roller cam thereby forcing the blade open.

18. The low friction folding knife of claim 17, further comprising an open safety engagement notch on the perimeter of the safety washer opposite the closed safety engagement notch such that when the folding knife is open, the safety stud moved to the safe position slides the safety engagement end into the open safety engagement notch thereby locking the folding knife open.

19. The low friction folding knife of claim 17, wherein the bias element having a finger cam clearance offset portion proximate the spring distal end that recesses into the spring cavity in the first liner allowing the passage of the finger cam by the bias element during opening and closing of the folding knife.

20. The low friction folding knife of claim 17, wherein the roller cam is hardened tool steel.

21. The low friction folding knife of claim 17, wherein the roller cam is ceramic.

22. A low friction folding knife, comprising: a blade having a distal end and a tang, the tang having an outer edge and a finger cam extending from the outer edge, the tang having a thickness with a slot disposed in the thickness, a roller cam rotatably attached in the slot by a keeper pin inserted perpendicular to the slot, the roller cam extending slightly outside the slot;a handle having a first outer handle parallel and attached to a first liner, a spring cavity and a safety cavity extending through the first liner, a second outer handle parallel and attached to a second liner, the first liner and the second liner spaced apart and parallel creating a blade slot for receiving the blade when the folding knife is closed, the blade being pivotally coupled to the handle with a pivot bolt;a safety washer fixedly attached to the tang and adjacent to the first liner, the safety washer having a closed safety engagement notch on the perimeter;a safety assembly having a safety engagement end and disposed within the first outer handle and held in place within the safety assembly cavity in the first liner, the safety assembly having a safety stud extending through a safety slot disposed in the first outer handle for moving the safety assembly between a safe position and a safe off position; anda bias element disposed in the spring cavity in the first liner, the bias element having a spring distal end and a spring attach end, the spring distal end has a contact end that is bent toward the blade slot to make spring communication with the roller cam on the tang, the spring attach end is fixedly attached within the spring cavity with only the contact end extending into the knife slot thereby eliminating contact between the bias element and the finger cam during opening and closing;wherein, the safety assembly in the safe position forces the safety engagement end into the closed safety engagement notch on the safety washer thereby preventing opening, the safety assembly in the safe off position retracts the safety engagement end from the closed safety engagement notch allowing opening of the blade, with pressure applied to the finger cam on the tang of the blade to rotate the blade out of the blade slot, the spring distal end of the bias element applies spring force on the roller cam thereby forcing the blade open.

23. The low friction folding knife of claim 22, wherein the spring attach end is press fitted into the spring cavity.

24. The low friction folding knife of claim 22, wherein the spring attach end is staked into the spring cavity.