US2243666A - Knife unit for meat cutters - Google Patents

Description

May 27, 1941.

I D. o. BECKNER KNIFE UNIT FOR MEAT CUTTERS Original Filed Feb. 24, 1939 Patented May 27, 1941 UNITED STATES TENT orrlo Divided and this application October H, 1939, Serial'No. 298,933

5 Claims.

My present invention relates to plural-bladed rotary knife units, including the knife or cutter proper and an associated die plate, particularly for meat cutters, and aims to provide extremely durable, non-corrosive and otherwise improved units of the character referred to. This application: a division of my Patent No. 2,176,867 dated October 24, 1939.

In the drawing illustrating by way of example one embodiment of the invention and certain steps for practicing its method-- Fig. 1 is a section through the delivery end of a meat cutter having a knife unit of the invention installed therein; 7

Fig. 2' is a plan of a core, blank or forging for the knife;

' Fig. 3 illustrates an early stage in the formation of the knife, showing in plan certain stainlesssteel members in position for uniting with the core of Fig. 2;

Fig. 4 is a plan view ofthe knife of Fig, 3 at an intermediate stage;

Fig. 5 shows in plan the knife of Figs. 3 and 4, inverted and in substantially complete form;

Figs, 2a, 3a., 4a and 5a are enlarged cross secknife, after grinding and polishing to the extent desired and Fig. 6a is an enlarged end View of one arm of said finished knife.

Referring to the drawing in more particular, in Fig. 11 have represented the delivery end of a typical meat cutter or grinder, including the mmn. head '3 housing the feed. screw 8 and having a retaining cap 9 threaded ontov its outer edge. The feed screw 8 has an outwardly projecting central shaft ill with a non-circular portion l l for receiving the knife, the latter indicated as a Whole by the numeral 5. The knife has a central correspondingly shaped aperture fitting said. noncircular portion of the shaft, so. that the knife is caused to rotate with the feed screw 8.

outwardly of the knife 55 is a stationary perforateplate. or die element It of novel construction. Desirably it is composed of a special extremely hard stainless steel, and. has formed integrally in one piece with it a central boss 13 apertured to receive and form a bearing for the outer cylindrical portion of the shaft it]. This die plate I2 is clamped in. fixed position in the head I, by the threaded cap 9, being held against turning as by a notch I4 at some peripheral portion of the plate engaging a correspondingly shaped projection on thehead. The platehas a multiplicity of apertures l2a drilled. through it, the meat being forced through the apertures by the feed screw and. out off by the knife rotating across them with its cutting edges contacting the inner or rear face of the plate.

Referring now more particularly to Figs. 2 to 6', and first to Fig, 2," I have there shown inplan a core, blank or forging indicated as a Whole by the numeral: l6. feet a base for the composite knife as a whole. It is forged or otherwise formed from ordinary relatively low-grade steel, such'as any good coldrolled steel, having substantial toughness, as contrasted with brittleness, but relatively soft and hence unsatisfactory for the formation of cutting edges which are subject to substantial wear.

Said core comprises a hub I! having a noncircular aperture to conform to the like-shaped portion II of the meat-cutter shaft In, Fig. 1.

The hub H has formed integrally with it a plurality of lateral arms 18 extending in a generally radial direction, one arm for each of the. blades of the knife. Any plurality of. blades and arms. may be employed, usually at least three, but in most instances I findv that four such elements,

disposed substantially at right angles to each other, are preferable; The arms l8 may be variously shaped in cross section; see for example Fig. 2a. and the other sectionalviews. one corresponding longitudinal side made approximately straight and flat, as indicated at I9.

As described inmy earlier application, this core or forging It is positioned substantially flatwise on a welding table, with either face up, that shown in Figs. 2, 3 and4 being the face corresponding to the outer or front. face of the finished knife. As illustrated in. Fig. 3, I apply along each of the arms it, in abutting relation to their fiat side faces it, a, rod or bar 2i] of a high-grade hard stainless steel. As clearly seen in the corresponding enlarged section, Fig, 3a, these rods are some- What larger in section than the arms of the core, and have a polygonal or other cross sectional shape herein rectangular, to provide along at least one longitudinal portion an angular corner section 2i adapted to constitute the cutting edge element for the corresponding finished blade.

With the parts positioned as in Figs. 3 and 3a the material at theupper and inner longitudinal portion of each stainless-steel rod 20, inwardly from the corner sections 2!, is subjected This element provides in ef- Each has to a fuse welding operation in the course of which it is flowed over onto and across the then upper face of the adjacent arm l8. During this operation said outer corner portions 2| of the stainless-steel rods 20 are kept intact, in their original condition. The resulting formation, wherein the arms l8 of the core and the juxtaposed stainless-steel elements 20 have been united into embryo blades 22,. is illustrated in Fig. 4 and Fig. 4a. In the several sectional views the original shape of the stainless-steel rods is indicated by the dotted lines.

The partly formed knife of Fig. 4 is then inverted and positioned on the welding table with its other face upward, as represented in Fig. 5 and as disclosed in said earlier application. The then upper longitudinal portions of the stainlesssteel rods 20, again excepting the corner portions 2|, are similarly fused and flowed across and about the adjacent portions of the corresponding arms l8, so as substantially to enclose the latter, and outer portions of the hub I! if desired, in a coating of said non-corrosive material; see particularly Fig. 5a.

It will be particularly noted that in any and all stages the stainless-steel material along the corner portions 2| of the rods is not touched but remains unchanged from its original condition and shape. Hence with the completion of the operation illustrated in Figs. 5 and 5a the knife l5 as a whole is substantially complete, subject only to such finishing byway of grinding and polishing as may be desirable. Since said corner portions 2| of the stainless-steel rods have not been fused or melted they are entirely free of irregularities such as blow holes which are likely to result from welding. Accordingly they present a uniform surface and edge available as the cutting element for the blades, with but a minimum of grinding or finishing to conform them to the inner face of the die plate [2 with which they are to cooperate.

Fig. 6 illustrates a completed knife, with its outer or front face upward, as in Figs. 2 to 4. The ends of the composite blades 22 may be rounded off as there shown, making them uniform and giving the knife an attractive appearance. The leading edge portions 2| of the several blades 22, provided by the intact corner portions of the stainless-steel rods, are ground to any extent necessary to sharpen their edges and true their front surfaces into a given plane, affording flat riding faces 23 for moving over and in contact with the die plate l2. The attractive appearance of the knife may be further improved by polishing, giving it a bright surface and making it easy to clean.

In the resulting knife substantially all surfaces which in operation come in contact with the meat are rendered non-corrosive, so that they are not affected by the acids of the meat, by the coating of stainless steel on the arms of the core or bas l6, completely along them to and onto the hub portion I! to any extent desired. The cutting and plate-engaging portions of the blades, being formed of the hard stainless steel, are extremely durable and in practice are found to stand up over long periods of use without sharpening or other attention. The composite knife, the method of making which as herein described and illustrated is claimed in my patent previously mentioned, is superior to one formed entirely of stainless steel of similar quality and hardness, due to the comparative brittleness of said material. Since the knife has in effect a base of the relatively soft but tough steel, by reason of the core or forging I6, breakage of the blades is reduced to a minimum, the operating stresses and vibrations being largely absorbed by the comparatively soft steel core. At the same time a substantial saving is effected in the quantity of the relatively expensive stainless steel employed, as contrasted with a cutter composed entirely of such material.

My invention is not limited to the particular embodiment as herein illustrated or described, its scope being pointed out in the following claims.

I claim:

1. A rotary knife for a meat cutter, comprising a core including a hub and a plurality of lateral arms, said core comprising a forging of a relatively soft tough steel, each arm of the core having along a corresponding side a relatively hard stainless-steel rod of original polygonal cross section and of which an outer longitudinal corner portion provides a cutting edge element along the corresponding arm, other portions of each rod being disposed around its arm as a coating substantially completely enclosing the latter and adjacent meat-contacting portions of the hub, whereby the knife as a whole presents to the meat a surface unaffected by the acids thereof and is equipped with cutting edge elements of extreme durability and so supported and connected by the tough, relatively soft core that breakage tendencies under operating stresses and vibrations are reduced to a minimum.

2. In a meat cutter, a knife comprising a core element of relatively soft steel including laterally extending integral arms each having one substantially straight side face, at corresponding sides, each arm having along its said side face an edge-forming relatively hard stainless-steel bar of polygonal cross section and having the material of said bar distributed as a coating substantially completely around the corresponding arm from its outer end inward for at least a major portion of its length and with one original longitudinal corner edge section of the bar providing a cutting edge along the full cutting length of the arm.

3. A rotary knife for a meat cutter, comprising a hub and a plurality of generally radial blades, each such bladeincluding a coextensive longitudinal supporting core of a relatively soft tough steel and having a substantially straight longitudinal side face, said core faces of the several blades being correspondingly disposed, and each blade also including a substantially enclosing coating of a relatively hard stainless steel material distributed from an angular-sectioned bar thereof set along the straight side face of its core and welded thereon with an intact longitudinal corner portion of said bar presenting the cut ting edge for the blade.

4. In a meat cutter, a knife unit comprising a one-piece perforate di plate element of superhard stainless steel, said plate element having, at one face only, an integral centrally disposed hub with a shaft-receiving bearing aperture, and a cooperating plural-bladed knife element comprising a core of relatively soft steel having a lateral arm for each blade, each arm having fuse welded thereon a substantially enclosing coating of a hard stainless steel derived from a juxtaposed bar thereof of polygonal cross section one edge and corner portion of which is preserved intact to provide the cutting edge for the particular blade.

5. A rotary meat-cutter knife comprising a centrally apertured hub and a plurality of substantially radial arms each with a cutting edge formation along its leading longitudinal edge,

said hub and arms constituted as a unit having 5 a core portion, for both the hub and the arms, of a relatively soft tough steel, such core portion of each arm having along the leading longitudinal edge thereof a bar of relatively hard stainless steel having one longitudinal portion 10 of angular form in cross section and disposed to tially completely around the corresponding arm from its outer end inward over substantially its full length and integrally uniting the cutting edge formation thereof with said core portion.

DONALD O. BECKNER.

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