System of chipper knives and knife stops

A system of chipper knives and knife stops for use in a disc chipper used to chip wood logs for the production of wood fiber containing pulp;

• the system comprising:
• a plurality of chipper knives, each chipper knife having a length, a width, and a thickness, wherein each chipper knife has an upper surface and a parallel lower surface, and along the length of the chipper knives at least one cutting edge plane extends from the upper surface to the lower surface to define a first cutting edge spaced in a width direction from a second engagement edge, the distance in the width direction between the first cutting edge and the second engagement edge defining the width of the chipper knife, and wherein each chipper knife of the plurality of chipper knives is releasably associated with the same chipper disc and extending within one of a plurality of pockets and positioned by a knife stop engaged against a back surface, said knife stop being one of a set of knife stops;
• for each of the plurality of chipper knives, the set of knife stops comprises:
• a series of knife stops, in which a first knife stop is narrower in the width direction than a second knife stop, which is narrower in the width direction than a third knife stop, and each member of the series of knife stops is narrower than the subsequent member;
• and
• such that all the first knife stops of all the sets of knife stops for all the chipper knives are of the same width, and the subsequent knife stops of all the sets are wider than the previous knife stops;
• such that as the plurality of chipper knives are repeatedly removed from their pockets and sharpened to a common and narrower width, the chipper knives may be returned to their association with the chipper disc, and the combined width of each sharpened chipper knife in combination with one of the subsequent knife stops remains the same, so the plurality of chipper knives are similarly positioned in the disc chipper.

A method of sharpening and using a plurality of chipper knives in a disc chipper, wherein each chipper knife has a first cutting edge spaced in a width direction from a second engagement edge, the method comprising the steps of:

• securing the plurality of chipper knives to a chipper disc, such that each chipper knife is engaged against a first knife stop of a first width in the width direction, wherein a combined width in the width direction of each combination of chipper knife and first stop is a first measure, and the first cutting edges are disposed to engage incoming wood logs;
• using the plurality of chipper knives in the disc chipper to chip wood logs until the plurality of chipper knife first cutting edges become dull;
• removing the plurality of chipper knives from the chipper disc;
• sharpening the chipper knife first cutting edges, thereby decreasing the widths of the chipper knives;
• removing the first knife stops and replacing them with second knife stops of a second width which is greater than the first width;
• replacing the plurality of sharpened chipper knives to engage against the second knife stops and securing them to the chipper disc, wherein the combined width of the each replaced sharpened chipper knife and its engaged second knife stop is said first measure;
• and
• using the plurality of chipper knives in the disc chipper to chip wood logs.