Abstract The knife blade disclosed has outer layers of a relatively soft carrier material, such as steel or aluminum, and an inner layer of relatively hard material such as tungsten carbide. The inner layer may be deposited on one or the other, or both outer layers, or may be bonded thereto as a separate member, or may be inserted in cavities defined by these outer layers of carrier material. When assembled, the thickness of the harder inner layer varies in the longitudinal direction so that when the longitudinally extending cutting edge is used to cut in a reciprocating action, said edge will wear away in an uneven fashion producing a serrated edge which need not be sharpened as frequently as a conventional knife blade.
A blade for cutting sheet material and comprising elongated carrier means having a longitudinally extending edge portion which defines a plurality of cavities opening laterally outwardly onto said carrier edge portion, a plurality of inserts in said cavities and made from a material which is considerably harder than the carrier material, said inserts being of generally elliptical cross sectional geometric shape and being equally spaced along the carrier edge portion to define a cutting edge in cooperation therewith.
Claim 2
Dependent Claim
78 words
A blade for cutting sheet material and comprising elongated carrier means having a longitudinally extending edge portion which defines a plurality of cavities opening laterally outwardly onto said carrier edge portion, a plurality of inserts in said cavities and made from a material which is considerably harder than the carrier material, said inserts being of generally elliptical cross sectional geometric shape and being equally spaced along the carrier edge portion to define a cutting edge in cooperation therewith.
Claim 3
Dependent Claim
33 words
A blade as set forth in claim 1 further characterized in that each insert has the longer of its elliptical axes being oriented in the longitudinal direction with respect to said carrier means.
Claim 4
Dependent Claim
107 words
A blade as set forth in claim 2 further characterized in that the generally elliptical cross sectional shape of each of said inserts is constant throughout its length, and said inserts being arranged adjacent one another in said carrier means to provide a series of valleys and ridges of said harder material, said cutting edge being defined by relieved side edges of said carrier means and thereby having alternately hard and less hard segments so that normal use tends to wear away the latter segments fastEr than the former with the result that said cutting edge tends to become serrated with use rather than merely becoming dulled.
Claim 5
Dependent Claim
53 words
A blade as set forth in claim 3 further characterized in that said carrier means comprises oppositely arranged layers of material each of which defines an alternating series of valleys and ridges, said valleys and ridges in one layer cooperating with those in the other layer to define said laterally outwardly opening cavities.