Cutting tool with a variable pivot system

Patent metadata

Field	Value
Publication number	US-9345200-B2
Application number	US-201414538130-A
Country	US
Kind code	B2
Filing date	Nov 11, 2014
Priority date	Nov 20, 2013
Publication date	May 24, 2016
Grant date	May 24, 2016

Abstract

A hand operated cutting tool includes a first cutting member; a first handle including a second cutting member, wherein the second cutting member is coupled to the first cutting member and includes a first set of projections; and a second handle including a lever, wherein the lever is coupled to the first cutting member and includes a second set of projections. The first and second handles are movable between a full open position and a full closed position, wherein during a first region of travel proximate the full open position the first and second set of projections are disengaged, and during a second region of travel proximate the full closed position the first and second set of projections are at least partly engaged.

First claim

What is claimed is:

1. A hand operated cutting tool, comprising:
a first cutting member;
a first handle including a second cutting member, wherein the second cutting member is coupled to the first cutting member and includes a first set of projections;
a second handle coupled to the first cutting member, wherein the second handle includes a lever that includes a second set of projections; and
a guide member coupled to the second cutting member;
wherein the first and second handles are movable between a full open position and a full closed position, wherein during a first region of travel proximate the full open position the first and second set of projections are disengaged, and during a second region of travel proximate the full closed position the first and second set of projections are at least partly engaged.

2. The hand operated cutting tool of claim 1 ,
wherein the first cutting member includes a first pivot point and a second pivot point; and
wherein the second cutting member is coupled to the first cutting member at the second pivot point and the lever is coupled to the first cutting member at the first pivot point.

3. The hand operated cutting tool of claim 1 , wherein the guide member includes a cam surface.

4. The hand operated cutting tool of claim 3 , wherein the lever includes a cam follower and a travel stop, wherein the cam follower travels along a continuous curvilinear path defined by an interaction between the cam follower and the cam surface in the first region of travel.

5. The hand operated cutting tool of claim 4 , wherein the interaction of the cam follower and the cam surface and an interaction between the travel stop and the first cutting member in the first region of travel proximate the full open position substantially prevents rotation of the lever.

6. The hand operated cutting tool of claim 4 , wherein at the end of the first region of travel proximate the full open position, the cam follower disengages from the cam surface, the travel stop disengages from the lever, and the first and second sets of projections at least partially engage to begin the second region of travel.

7. The hand operated cutting tool of claim 1 , wherein the second region of travel proximate the full closed position corresponds with a relatively greater mechanical advantage than the first region of travel proximate the full open position due to the at least partly engaged first and second set of projections.

8. The hand operated cutting tool of claim 1 , wherein the first and second set of projections are structured as first and second gear projections with at least a partially elliptical pitch.

9. The hand operated cutting tool of claim 1 , wherein the hand operated cutting tool is structured as a lopper.

10. The hand operated cutting tool of claim 1 , wherein the first region of travel corresponds with a handle angle between the first and second handles of approximately 140 degrees to 115 degrees, and wherein the second region of travel corresponds with a handle angle between the first and second handles of approximately 115 to 5 degrees.

11. A hand operated cutting tool, comprising:
a first cutting member including a first pivot point and a second pivot point;
a second cutting member coupled to the first cutting member at the second pivot point, wherein the second cutting member includes a first set of gear projections;
a lever coupled to the first cutting member at the first pivot point, wherein the lever includes a second set of gear projections; and
a guide member coupled to the second cutting member;
wherein the first and second cutting members are movable between a full open position and a full close position that defines a cutting stroke, wherein the first and second set of gear projections are disengaged during a first region of the cutting stroke and at least partly engaged during a second region of the cutting stroke.

12. The hand operated cutting tool of claim 11 , wherein the first region defines approximately one-third of the cutting stroke and the second region defines approximately two-thirds of the cutting stroke.

13. The hand operated cutting tool of claim 11 , wherein the lever rotates about the first pivot point in the second region of the cutting stroke.

14. The hand operated cutting tool of claim 11 , further comprising:
a cam follower coupled to and extending from the lever; and
a travel stop coupled to the lever, wherein the travel stop extends from the lever in an opposite direction relative to that of the cam follower.

15. The hand operated cutting tool of claim 14 , wherein an interaction of the cam follower and the guide member and an interaction of the travel stop and the first cutting member substantially prevents rotation of the lever about the first pivot point during the first region.

16. The hand operated cutting tool of claim 11 , wherein the first and second set of gear projections have at least a partially elliptical pitch.

17. The hand operated cutting tool of claim 11 , wherein the first cutting member includes a blade and wherein the second cutting member includes a hook.

18. A method for operating a hand operated cutting tool, comprising:
providing a first cutting member including a first pivot point and a second pivot point;
providing a second cutting member coupled to the first cutting member at the second pivot point, wherein the second cutting member includes a first set of projections;
providing a lever coupled to the first cutting member at the first pivot point, wherein the lever includes a second set of projections; and
providing a guide member coupled to the second cutting member;
wherein during a cutting stroke, the first and second cutting members are movable between a full open position and a full close position;
wherein during a first region of travel proximate the full open position of the cutting stroke, the first and second set of projections are disengaged; and
wherein during a second region of travel of the cutting stroke proximate the full close position, the first and second sets of projections are at least partly engaged.

19. The method of claim 18 , wherein the first region of travel defines approximately one-third of the cutting stroke and the second region of travel defines approximately two-thirds of the cutting stroke.

Assignees

• Fiskars Brands Inc

Inventors

• Cunningham Daniel

Classifications

• A01G3/02

  Secateurs; Flower or fruit shears · CPC title

• A01G3/021

  characterized by the arrangement of pivots · CPC title

• Y10T83/04

  Processes · CPC title

• A01G3/0251 Primary

  Loppers, i.e. branch cutters with two handles (hedge shears A01G3/0475) · CPC title

• B26B13/26 Primary

  with intermediate links between the grips and the blades, e.g. for remote actuation · CPC title