Apparatus for breaking brittle rods or fibers

A hand tool for breaking a rod of brittle material comprising:

• first and second handles arranged in a plierslike configuration so as to pivot relative to each other about a principal tool axis;
• one pair of adjacent ends of said handles being adapted for gripping;
• a post being mounted at a selected point at the other end of said first handle;
• a pair of spaced, L-shaped rod holding clamps being mounted pivotally at separate points near the other end of said second handle respectively on opposite sides of the post for holding a rod-supporting member against the upward thrust of said post when said handles are squeezed together;
• said rod-supporting member being bendable when said handles are squeezed together and such that there is essentially no relative motion between said rod and said support member when said rod is held by said support member and said L-shaped clamps facilitating the breaking thereof.

Apparatus for breaking brittle material in the form of a rod having an axis, said apparatus having means for producing a score on said rod, means for holding said rod on either side of said score, and causing a fracture to propagate from said score characterized in that

• said apparatus is specifically adapted for breaking a fibrous, relatively bendable rod of said material in that
• said holding means comprises a first clamp having surfaces for clamping said fibrous rod in place at one point and a second clamp having surfaces for clamping said fibrous rod in place at a second point, said second clamp being adjustably movable along the direction of the axis of said fibrous rod thereby adjustably applying tension to said fibrous rod;
• and said apparatus further comprises a form having a surface having a radius of curvature adjustably movable and located relative to said holding means so that a portion of said fibrous rod between said clamps assumes said radius of curvature when taut, said second clamp and said form being sufficiently adjustable so that an always-positive stress distribution is produceable in said fibrous rod,
• whereby said fibrous rod is able to be broken with a substantially perfect mirror zone fracture.