Cutting tool with a variable pivot system

Abstract

A hand operated cutting tool includes a first handle coupled to a first cutting member, the first handle having a first set of projections; and, a second handle coupled to a second cutting member and movably coupled to the first handle, the second handle having a second set of projections. The handles are movable between a full open position and a full closed position, wherein a first region of movement is defined by the first and second sets of projections being at least partly engaged, and wherein a second region of movement is defined by the first and second sets of projections being disengaged.

What is claimed: 
     
         1 . A hand operated cutting tool, comprising:
 a first handle having a cam follower and a first set of projections; and   a second handle movably coupled to the first handle, the second handle having an elongated member, wherein the elongated member has a cam surface and a second set of projections;   wherein the handles are movable between a full open position and a full closed position, wherein a first region of movement is defined by the first and second sets of projections being at least partly engaged, and wherein a second region of movement is defined by the first and second sets of projections being disengaged.   
     
     
         2 . The hand operated cutting tool of  claim 1 , wherein the elongated member at least partially overlays the first handle throughout a movement of the handles from the full open position to the full closed position, and wherein the second set of projections are positioned on an interior surface proximate the first handle of the elongated member. 
     
     
         3 . The hand operated cutting tool of  claim 1 , wherein the cam surface is positioned directly above the second set of projections on the elongated member. 
     
     
         4 . The hand operated cutting tool of  claim 1 , wherein the first region of the movement is also defined by the cam follower and the cam surface being disengaged, and wherein the second region of the movement is also defined by the cam follower and the cam surface being engaged. 
     
     
         5 . The hand operated cutting tool of  claim 1 , further comprising:
 a first locking projection coupled to the first handle; and   a second locking projection coupled to the second handle.   
     
     
         6 . The hand operated cutting tool of  claim 5 , wherein during the second region of the movement, the first locking projection and the second locking projection are engaged. 
     
     
         7 . The hand operated cutting tool of  claim 1 , wherein the first and second sets of projections are structured as gear projections. 
     
     
         8 . A hand operated cutting tool, comprising:
 a first handle having a pin, a cam follower, and a first set of projections;   a first cutting member having a bore, wherein the bore is structured to receive the pin to couple the first handle to the first cutting member; and   a second handle movably coupled to the first handle, the second handle having a second cutting member and an elongated member, wherein the elongated member has a cam surface and a second set of projections;   wherein the handles are movable between a full open position and a full closed position, wherein a first region of movement is defined by the first and second sets of projections being at least partly engaged, and wherein a second region of movement is defined by the first and second sets of projections being disengaged   
     
     
         9 . The hand operated cutting tool of  claim 8 , wherein the first region of the movement is also defined by the cam follower and cam surface being disengaged, and wherein the second region of the movement is also defined by the cam follower and the cam surface being engaged. 
     
     
         10 . The hand operated cutting tool of  claim 8 , wherein the cam surface is positioned directly above the second set of projections on the elongated member. 
     
     
         11 . The hand operated cutting tool of  claim 8 , further comprising:
 a first rotation stop coupled to the first handle;   a second rotation stop coupled to a first cutting member;   a first locking projection coupled to the first handle; and   a second locking projection coupled to the second handle.   
     
     
         12 . The hand operated cutting tool of  claim 11 , wherein during the first region of the movement, the first handle rotates relative to the first cutting member, and wherein during the second region of the movement, the first rotation stop and the second rotation stop are at least partly engaged as are the first locking projection and the second locking projection to substantially prevent rotation of the first handle to the first cutting member during the second region of the movement. 
     
     
         13 . A hand operated cutting tool, comprising:
 a first cutting member;   a first handle including a second cutting member, wherein the second cutting member is pivotably coupled to the first cutting member, and wherein the second cutting member includes a first set of projections;   a second handle coupled to the first cutting member, wherein the second handle includes a lever coupled to the first cutting member, wherein the lever includes a second set of projections and a cam follower; and   a guide structure coupled to the second cutting member, the guide structure including a cam surface;   wherein the first handle and the second handle are movable between a full open position and a full closed position, wherein in the full open position the first and second sets of projections are disengaged and in the full close position the first and second sets of projections are at least partly engaged.   
     
     
         14 . The hand operated cutting tool of  claim 13 , wherein the cam follower travels along a continuous curvilinear path defined by an interaction between the cam follower and the cam surface as the first and second handles move from the full open to the full close position. 
     
     
         15 . The hand operated cutting tool of  claim 13 , wherein the lever includes a travel stop, wherein an interaction between the cam follower and the cam surface and an interaction between the travel stop and the first cutting member substantially prevents rotation of the lever about the first cutting member. 
     
     
         16 . The hand operated cutting tool of  claim 15 , wherein at the full open position, the cam follower engages the cam surface, the travel stop engages the lever, and the first set of projections and the second set of projections are disengaged. 
     
     
         17 . The hand operated cutting tool of  claim 13 , wherein a cutting stroke is defined by the first handle and the second handle moving between the full open position to the full closed position, wherein a first region of the cutting stroke is proximate the full open position and a second region of the cutting stroke is proximate the full closed position, wherein the first region of the cutting stroke corresponds with a handle angle between the first handle and the second handle of approximately 140 degrees to 115 degrees, and wherein the second region of the cutting stroke corresponds with a handle angle between the first handle and the second handle of approximately 115 to 5 degrees. 
     
     
         18 . The hand operated cutting tool of  claim 13 , wherein the guide member projects outward and away from the second cutting member toward the lever. 
     
     
         19 . The hand operated cutting tool of  claim 18 , wherein the guide member at least partially overlays each of the first cutting member, the second cutting member, and the lever. 
     
     
         20 . The hand operated cutting tool of  claim 13 , wherein the hand operated cutting tool is a lopper.