Blade sharpening apparatus and methods of making and using same

A method of grinding a blade comprising a plurality of teeth and setting the blade by providing an offset to the plurality of teeth, the method comprising:

• securely holding the blade as a grinding wheel is moved along a profile thereof responsive to an actuation input received via an input shaft to grind the teeth at the grinding wheel;
• respectively pivoting, via first and second bending cams actuated by a camshaft, first and second levers about respective pivot points to provide the offset by selectively setting each tooth inwards or outwards or leaving the tooth in place according to a setting pattern;
• engaging each tooth, at a pawl mechanically connected to the input shaft, to advance the blade one tooth at a time, the pawl configured to feed and release the blade as the input shaft receives the actuation input, thereby selectively permitting the blade to advance by lifting up over each tooth and dropping into a gullet of a subsequent tooth;
• engaging with the pawl, at an upper crank arm, to move the pawl along the blade, wherein the upper crank arm is connected to a lower crank arm in communication with a rotating plate for receiving rotation from the camshaft;
• and
• enabling, at a tracer arm shaft, tracing out a predefined grinding pattern by communicating with the predefined grinding pattern, wherein the tracer arm shaft has a radially slotted arm rigidly attached thereto for engaging with a double-ended stylus, wherein the double-ended stylus is attached to a tracer arm for following the predefined grinding pattern including tracing out the predefined grinding pattern with the opposite end of the stylus.

A method of assembling an apparatus for grinding a blade comprising a plurality of teeth and for setting the blade by providing an offset to the plurality of teeth, the method comprising:

• providing a grinding head comprising a grinding wheel for grinding the blade;
• disposing below the grinding wheel a plurality of clamping jaws for securely holding the blade as the grinding wheel is moved along a profile thereof responsive to an actuation input;
• providing first and second bending cams configured to be actuated by a camshaft;
• providing first and second levers configured to be pivoted by the first and second bending cams, respectively, about respective pivot points to provide the offset by selectively setting each tooth inwards or outwards or leaving the tooth in place according to a setting pattern;
• providing an input shaft for receiving the actuation input, the input shaft comprising a roller chain sprocket, a camshaft for actuating the first and second bending cams, the camshaft comprising a camshaft sprocket, and a tracer arm comprising a tracer sprocket;
• connecting, via a chain, the input shaft at the roller chain sprocket with the tracer arm at the tracer sprocket and the camshaft at the camshaft sprocket thereof, the roller chain sprocket configured, upon receiving the actuation input via the input shaft, to drive the tracer arm and the camshaft;
• providing a tracer arm shaft for enabling tracing out a predefined grinding pattern by communicating with the predefined grinding pattern, wherein the tracer arm shaft has a radially slotted arm rigidly attached thereto for engaging with a double-ended stylus, wherein the double-ended stylus is attached to a tracer arm for following the predefined grinding pattern including tracing out the predefined grinding pattern with the opposite end of the stylus;
• providing an upright to which the tracer arm is hingedly attached, the upright mounted on a linear rail bearing for guiding movement of the tracer arm, and a top arm attached to the grinding head and disposed at a top portion of the upright at a hinged joint, wherein as the tracer arm follows the predefined grinding pattern, the top arm is configured to follow the predefined grinding pattern;
• providing a depth adjustment rod for connecting and separating the grinding head from the tracer arm to keep the tracer arm and the grinding head mutually synchronized;
• providing a pawl mechanically connected to the input shaft for engaging each tooth to advance the blade one tooth at a time, the pawl configured to feed and release the blade as the input shaft receives the actuation input, thereby selectively permitting the blade to advance through the apparatus by lifting up over each tooth and dropping into a gullet of a subsequent tooth;
• providing an upper crank arm for engaging with the pawl to move the pawl along the blade and a lower crank arm connected to the upper crank arm and in communication with a rotating plate for receiving rotation from the camshaft;
• and
• providing:
• first and second precision guide blocks respectively comprising first and second dies for pushing against the plurality of teeth to provide the offset, wherein the first and second levers are configured to push against the first and second dies, respectively;
• or:
• providing first and second adjustable pins protruding from the first and second levers, respectively, and configured to work on an arc to provide the offset.