Shearing tool for synthetic resin tubes

Abstract

A shearing tool for synthetic resin tubes, in which a lower jaw is connected to the leading end of an upper handle portion, a lower handle portion is pivoted to said lower jaw at its leading end, an opening is provided in forward portion of said upper handle portion extending therefrom to the leading end of said lower jaw, an arcuate tube receiving recess is provided in the upper surface of said lower jaw, said shearing blade is pivoted in an intermediate position of the length to said upper handle portion within said opening, said shearing blade is provided at the rear and lower end with an engaging pawl, a rocking bar having notches in the upper surface is pivoted at one end to the leading end of a lower handle portion, a slot is provided in the rear portion of said shearing blade, a connection link has at one end a pin freely received within said slot and is pivoted at the other end to an intermediate position of the length of said rocking bar, a spring is provided for urging said rocking bar against said engaging pawl and a spring is provided for normally urging said upper and lower handle portions away from each other.

What is claimed is: 
     
       1. A shearing tool for synthetic resin tubes comprising: an upper handle portion; a lower jaw connected to the leading end of said upper handle portion and provided with an arcuate tube receiving recess in the upper surface of said jaw;   said upper handle portion being further provided with a blade receiving opening extending from the forward portion of said upper handle portion to the leading end of said lower jaw;   a lower handle portion pivoted at the leading end of said lower handle portion to said lower jaw;   a shearing blade pivoted in an intermediate position of the length of said blade to said upper handle portion within said opening and having an engaging pawl formed at and extending downwardly from the rear end of said blade;   said shearing blade further including a slot formed in the rear portion thereof;   a rocking bar pivoted at one end to the forward portion of said lower handle portion and provided with notches in the upper surface of the rocking bar;   a connection link pivoted at one end to an intermediate position of the length of said rocking bar and having at the other end a pin freely received within said slot in the blade;   a spring normally urging said rocking bar against said engaging pawl; and   a return spring for returning said lower handle portion to the initial position when a gripping force is released from said upper and lower handle portions.   
     
     
       2. The shearing tool as set forth in claim 1, in which said lower jaw is connected to said leading end of the upper handle portion by means of a neck portion. 
     
     
       3. The shearing tool as set forth in claim 1, in which a washer is provided about said pivot connection of said shearing blade to said upper handle portion within said opening in abutment against the side of the blade to hold the blade in position. 
     
     
       4. The shearing tool as set forth in claim 1, in which said lower handle portion is provided with a pin which is adapted to engage said rocking bar. 
     
     
       5. The shearing tool as set forth in claim 1, said notches are in series, and the series of notches are inclined with respect to the longitudinal axis of the cutting edge of said shearing blade in the counterclockwise direction. 
     
     
       6. The shearing tool as set forth in claim 5, in which said series of notches have engaging faces disposed substantially normal to the longitudinal axis of said rocking bar. .Iadd. 7. A shearing tool for cutting elongated stock and the like comprising: first and second handles;   said first handle having a J-shaped jaw fixed to and projecting from the forward portion of the first handle, and said second handle being pivotally connected to and projecting rearwardly from the bottom of the stem portion of the J;   an elongated cutting blade pivotally supported at the mid-length thereof near the top of the jaw stem portion;   a rock lever pivoted at one end to said second handle at a point spaced from the lower end of the jaw stem and provided with a plurality of ratchet teeth along the edge thereof facing toward the rear end of said cutting blade;   link means having one end pivoted to the mid-length of said rock lever and having a lost motion connection between the other end thereof and the rear portion of said cutting blade;   the rear end of said cutting blade having a pawl positioned to engage successive ones of said ratchet teeth during successive movements of said first and second handles toward and away from one another; and   means biasing said rock lever toward engagement with said pawl on said   
     
     
        cutting blade. .Iaddend. .Iadd. 8.  A shearing tool as set forth in claim 7 in which the ends of said link means respectively straddle said rock lever and said cutting blade and cooperate therewith in holding said pawl and said ratchet teeth in planar alignment with one another. .Iaddend. 
     
     
        .Iadd.9.  A shearing tool as set forth in claim 7 including a stop positioned to limit pivotal movement of said rock lever toward said pawl and cooperating with said lost motion connection to permit said ratchet teeth to under-ride said pawl as said first and second handles are pivoted apart to restore said blade to the open position thereof. .Iaddend. .Iadd.10. A shearing tool as set forth in claim 9 in which said lost motion connection includes an elongated slot in the rear end portion of said blade loosely seating therein a pivot connection to the adjacent end of said link means. .Iaddend. .Iadd.11. A shearing tool as set forth in claim 7 including means frictionally restraining said blade against 
     
     
        pivotal movement about said pivot support therefor. .Iaddend. .Iadd.12.  A shearing tool as set forth in claim 7 in which said blade is pivotally supported lengthwise of an elongated slot extending along the stem of said J-shaped jaw and the forward end of said first handle. .Iaddend. 
     
     
        .Iadd.     A shearing tool as set forth in claim 12 in which said pivot support for said blade comprises bolt and washer means on said bolt, said bolt extending through said blade and the portions of said stem to either side thereof which bolt is tightened to compress said stem into frictional contact with a juxtaposed face of said blade thereby to prevent unintended pivotal movement of said blade the blade being compressed between the end of said washer means and the face of said slot on the opposite side of the 
     
     
        blade from the washer means. .Iaddend. .Iadd.14.  A shearing tool as set forth in claim 7 in which said J-shaped jaw is slotted to receive the adjacent edge of said cutting blade when the blade is pivoted to the closed position thereof. .Iaddend. .Iadd.15. A cutting tool as set forth in claim 7 in which said biasing means includes spring means tending to urge said first and second handles apart and the teeth of said rock lever toward engagement with said pawl on said blade. .Iaddend. .Iadd.16. A cutting tool as set forth in claim 15 in which said spring biasing means includes spring means constantly urging said first and second handles apart. .Iaddend. .Iadd.17. A cutting tool as set forth in claim 7 in which said biasing means comprises spring means constantly urging the outer end of said rock lever to pivot away from said second handle and toward the pawl of said blade. .Iaddend. .Iadd.18. A cutting tool as set forth in claim 7 including stop means interposed between said second handle and said rock lever positioned to limit the pivotal movement of said rock lever toward said pawl thereby to hold said ratchet teeth out of contact with said pawl during movement of said first and second handles toward the 
     
     
        spaced apart open positions thereof. .Iaddend. .Iadd.19.  A shearing tool as defined in claim 7 characterized in that said pivot support for said blade includes frictional resistance auqmentation means for varying the resistance of said blade to pivot about the axis of said pivot support. 
     
     
        .Iaddend. .Iadd.20.  A shearing tool for cutting elongated stock and the like comprising: first and second handles;   said first handle having a J-shaped jaw fixed to and projecting from the forward portion thereof and the second handle being pivotally connected to and projecting rearwardly from the bottom of the stem portion of the J;   an elongated cutting blade pivotally supported at the mid-length thereof near the top of said jaw stem portion;   a rock lever pivoted at one end to said second handle at a point spaced from the lower end of said jaw stem portion and extending crosswise of the adjacent end of said blade and having the free end thereof spring-biased toward engagement with said blade end; and   the free end of said rock lever and the adjacent and of said cutting blade being inter-engageable by a pawl and a series of ratchet teeth, said pawl and said teeth being relatively movable and sequentially interengageable at substantially the same distance from said blade pivot and cooperable with one another to provide the same mechanical advantage as said first and second handles are operated through successive opening and closing   
     
     
        cycles. .Iaddend. .Iadd.21.  A shearing tool as defined in claim 19 characterized in the provision of means operatively interconnecting said cutting blade and said rock lever for pivoting said blade away from said J-shaped jaw as said first and second handles are pivoted away from one another. .Iaddend. .Iadd.22. A shearing tool as defined in claim 21 characterized in the provision of stop means fixed to said second handle and positioned to limit the movement of said rock lever away from the 
     
     
        adjacent end of said blade. .Iaddend. .Iadd.23.  A shearing tool as defined in claim 21 characterized in that said J-shaped jaw and the adjacent end of said first handle are slotted longitudinally thereof and a substantial portion of said cutting blade being located in said slot and pivotally supported on a pivot pin extending crosswise of said slot adjacent the junction of said first handle and said J-shaped jaw. .Iaddend. .Iadd.24. A shearing tool as defined in claim 21 characterized in that said second handle in a one-piece molded unit, and in that said first handle and said J-shaped jaw is a one-piece molded unit. .Iaddend. .Iadd.25. A shearing tool as defined in claim 23 characterized in that said pivot pin includes frictional resistance augmentation means for varying the force required to be applied to said blade to pivot the same about said pivot pin. .Iaddend. .Iadd.26. A shearing tool as defined in claim 21 characterized in that said pivot support for said blade includes washer means encircling a bolt passing through said blade and into a threaded bore in said first handle, said bolt being wrenchable to vary the frictional resistance between the faces of said blade and the juxtaposed surfaces of said first handle and said washer means.