Self-locking cutting tool for plastic pipes

Abstract

A locking mechanism for a cutting tool for plastic pipes. The tool includes two elongated members pivotally connected to each other in a scissors-like manner. Each elongated member has a handle portion and a jaw portion with one jaw portion including a knife blade and the other an anvil. In the preferred embodiments, the jaws of the cutting tool are spring-biased apart toward an open position. The locking mechanism for the tool includes a bail member on one handle and a C-shaped catch member on the other. In operation, the bail member can be pivoted to an extended position to contact and automatically slide along the opposite handle into a locking position with the catch member as the handles are squeezed together.

1 . A cutting tool ( 1 ) primarily intended for cutting plastic pipe ( 2 ) said cutting tool including first and second elongated members ( 3 , 5 ) connected to each other for pivotal movement about a first pivotal axis ( 9 ) between the respective ends ( 3 ′,  3 ″ and  5 ′,  5 ″) of the first and second elongated members,
 said first elongated member ( 3 ) having a curved anvil ( 13 ) adjacent one end ( 3 ′) thereof and a handle portion ( 3 ″) adjacent the other end, said second elongated member ( 5 ) having a knife blade ( 11 ) adjacent one end ( 5 ′) thereof and a handle portion ( 5 ″) adjacent the other end, said knife blade ( 11 ) having a cutting edge ( 11 ′) and said curved anvil ( 13 ) of said first elongated member ( 3 ) having a slot ( 131 ) therein for receiving the cutting edge ( 11 ′) of said knife blade ( 11 ) when said elongated members ( 3 , 5 ) are moved to a closed position by squeezing said handle portions ( 3 ″, 5 ″) together,   said cutting tool ( 1 ) further including a spring ( 15 ) to bias said handle portions ( 3 ″, 5 ″) of said elongated members ( 3 , 5 ) apart toward an open position to separate said knife blade ( 11 ) and curved anvil ( 13 ) to receive the pipe ( 2 ) therebetween, and   a locking mechanism to selectively lock said first and second elongated members ( 3 , 5 ) in said closed position, said locking mechanism including a substantially U-shaped bail member ( 20 ) and a catch member ( 40 ) with a substantially C-shape with a center section ( 43 ) and a freestanding end portion ( 41 ), said U-shaped bail member ( 20 ) having two legs ( 22 ) and a base portion ( 24 ) extending therebetween, said legs being pivotally mounted to the handle portion of one of the elongated members for movement relative thereto about a second pivotal axis ( 30 ) with the base portion ( 24 ) of the bail member ( 20 ) spaced from said second pivotal axis ( 30 ), said C-shaped catch member ( 40 ) being fixedly mounted to the handle portion of the other elongated member and having a freestanding end portion ( 41 ) positioned at a location along said other elongated member spaced farther from the first pivotal axis ( 9 ) of the cutting tool ( 1 ) than the spacing of said second pivotal axis ( 30 ) of the bail member ( 20 ) from said first pivotal axis ( 9 ) wherein said second pivotal axis ( 30 ) of said bail member ( 20 ) is spaced closer to said first pivotal axis ( 9 ) than said freestanding end portion ( 41 ) of said C-shaped catch member ( 40 ),   said handle portion of the other elongated member having a surface ( 5 ″′) extending away from the first pivotal axis ( 9 ) of the cutting tool ( 1 ) toward the C-shaped catch member ( 40 ), said bail member ( 20 ) being manually positionable about the second pivotal axis ( 30 ) with the legs ( 22 ) thereof extending toward the handle portion of the other elongated member and with the base portion ( 24 ) of the bail member ( 20 ) positioned to abut the surface ( 5 ″′) of the handle portion of the other elongated member at an acute angle (A) as the handle portions ( 3 ″, 5 ″) are moved together toward said closed position, said base portion ( 24 ) of the bail member abutting and sliding along said surface ( 5 ″′) away from said first pivotal axis ( 9 ) as said handle portions ( 3 ″, 5 ″) are moved together to engage said bail member ( 20 ) with the freestanding end portion ( 41 ) of said C-shaped catch member ( 40 ) at a location spaced from the center section ( 43 ) of the C-shape of the catch member ( 40 ) in a locking position to secure said elongated members ( 3 , 5 ) in said closed position.   
   
   
       2 . The cutting tool of  claim 1  wherein the base portion ( 24 ) of the bail member is positionable about said second pivotal axis ( 30 ) in a non-locking position extending outwardly beyond the handle portion of the one elongated member relative to the first pivotal axis ( 9 ). 
   
   
       3 . The cutting tool of  claim 1  wherein said handle portion of the one elongated member has a substantially U-shaped inner cross section with two legs ( 56 ) and a base portion ( 58 ) extending therebetween, said bail member being pivotally mounted to the base portion ( 58 ) of the inner cross section. 
   
   
       4 . The cutting tool of  claim 3  wherein said bail member is pivotally mounted to said handle portion by a frictional fitting ( 28 ) wherein said bail member frictionally resists being moved about said second pivotal axis ( 30 ). 
   
   
       5 . The cutting tool of  claim 1  wherein said bail member is pivotally mounted to said handle portion by a frictional fitting ( 28 ) wherein said bail member frictionally resists being moved about said second pivotal axis ( 30 ). 
   
   
       6 . The cutting tool of  claim 1  wherein the legs ( 22 ) of the bail member extend away from one another in a direction from the second pivotal axis ( 30 ) toward the base portion ( 24 ) of the bail member. 
   
   
       7 . The cutting tool of  claim 1  further including pivot members ( 26 ) mounted on the legs ( 22 ) of the bail member to extend toward one another along the second pivotal axis ( 30 ). 
   
   
       8 . The cutting tool of  claim 7  wherein the pivot members ( 26 ) are mounted to the handle portion of the one elongated member by a frictional fitting ( 28 ) to resist movement of the bail member relative to the handle portion about the second pivotal axis ( 30 ). 
   
   
       9 . The cutting tool of  claim 1  wherein said C-shaped catch member ( 40 ) extends away from the surface ( 5 ″′) of the handle portion of the one elongated member in a direction toward the handle portion of the other elongated member. 
   
   
       10 . The cutting tool of  claim 9  wherein the handle portion of the other elongated member has a substantially U-shaped inner cross section and at least a portion of the C-shaped catch member is received in said cross section when the elongated members are moved together. 
   
   
       11 . The cutting tool of  claim 1  wherein the handle portion of the other elongated member has a substantially U-shaped inner cross section and at least a portion of the C-shaped catch member is received in said cross section when the elongated members are moved together. 
   
   
       12 . The cutting tool of  claim 1  wherein said spring with said bail member and C-shaped catch member engaged biases said bail member and C-shaped catch member in said locking position. 
   
   
       13 . The cutting tool of  claim 12  wherein said spring is a leaf spring. 
   
   
       14 . The cutting tool of  claim 1  wherein said second elongated member ( 5 ) is received in a central aperture ( 21 ) through said first elongated member ( 3 ).