Granulator device and helical-shaped cutters therefor

Claim 2

Granulator apparatus for cutting material comprising an elongated first cutter member having a plurality of helically arranged cutting teeth, a second cutter member having a plurality of helically arranged cutting teeth meshing with and driving said plurality of cutting teeth of said first cutting means for mounting and rotatably driving said first and second cutter members with the driving side edges of the tips of the teeth on said second cutter member being in driving engagement with the driven side edges of the tips of the teeth on the first cutter member, the lines of intersection of the outer peripheries of the cutter members with said side edges forming cutting edges which cooperate to shear material placed between them immediately prior to the time at which the side edges on the second cutter member commence to overlap the side edges of the first cutter member and permit the cutting edges of the second cutter member to drive the cutting edges of the first cutter member, the tips of said teeth of the second cutter member measured along a circle at their maximum depth of overlapping penetration into the tooth spaces of the first cutter having a thickness no greater than 40 percent of the tooth to tooth distance between corresponding points of adjacent teeth as measured along the same circle, the maximum overlapping penetration of the tips of the teeth on said first and second cutter members being limited to facilitate exit of cut material from the tooth spaces, said shearing engagement taking place progressively and continuously along the length of several teeth at one time at points spaced from a plane containing their axes.

Claim 3

The granulator of claim 1 wherein said first and second cutter members comprise a first set of cutters which are adapted to shear material fed downwardly into their bite into a plurality of parallel strips which are formed at an angle to their direction of feed which is equal to the helix angle of the cutters forming them; said granulator further including a second set of cutters mounted adjacent to said first set and having its bite directly beneath the bite of the first set, the second set of cutters comprising third and fourth cutter members which are similar to said first and second cutter members respectively except that the helix angles of their teeth are arranged transversely to those of the cutter members positioned directly above them, whereby the parallel strips of material fed to them by the first set of cutters will be transversely sheared into generally rectangular-shaped particles.

Claim 4

The granulator of claim 1 and further including recirculating means for receiving material sheared by said cutter members and ejecting any portion of the material which is of smaller dimension than a predetermined size and carrying the remaining portion of the material upwardly around the cutter members and representing it to the bite of the cutter members.

Claim 5

The granulator of claim 3 wherein said recirculating means includes means for moving material being carried upwardly around the cutter members in a direction longitudinally of the cutter members and opposite to the general longitudinal direction in which the material is moved when it is engaged by the helical cutter members.

Claim 6

The granulator of claim 4 wherein said means for moving material comprises a source of air which is directed against material being recirculated to the cutter members to cause it to be moved and evenly distributed over the length of the cutter members.

Claim 7

The granulator of claim 3 wherein said recirculating means comprises screen means which is positioned adjacent the bottom and outer peripheral side portions of the cutter members, said screen means being perforated with openings corresponding in size to the size of the largest particle of cut material to be ejected, said recirculating means further comprising deflecting members for intercepting cut material guided upwardly by said screen member and directing it into the bite of the cutter members.

Claim 8

The granulator of claim 1 wherein each cutter member has its helically arranged teeth in a herringbone pattern wherein the teeth along one longitudinal portion of the cutter have a helix angle arranged transversely of the helix angle of the teeth of an adjacent longitudinal portion.

Claim 9

The granulator of claim 1 wherein said teeth on said second cutter member have a maximum tooth penetration into the tooth spaces of the first cutter member of 35 percent of their length and a maximum tooth thickness of 25 percent of said tooth to tooth distance, the sides of the teeth on said first and second cutter members being relieved behind their cutting edges to prevent contact of the teeth of said cutters except by their cutting edges.

Claim 10

A pair of cutting members for use in a granulating device comprising: a first rotatable, generally cylindrical cutting member having a plurality of helically arranged teeth, at least a portion of which are of a predetermined hand and arranged along its ouTer periphery at a predetermined helix angle relative to a plane passing through the axis of the cutter member; a second rotatable, generally cylindrical cutting member having a plurality of helically arranged teeth adapted to be positioned in driving meshing engagement with the teeth on said first cutting member the teeth on said second cutter being of an opposite hand and of an equal but opposite helix angle relative to the teeth which they engage on the first cutter member; said teeth on each of said cutters having cutting edges which are adapted to cooperate to shear material fed into their bite and to transmit driving motion of said second cutter members to said first cutter member, said cutting edges being defined by the lines of intersection of a side profile of each of said teeth with its outer periphery, said teeth on said second cutter member having tips which are of a thickness measured along a circle at their maximum depth of penetration into the tooth spaces of the first cutter member of no more than 40 percent of the distance between corresponding points of adjacent teeth on the same circle, the penetration of the teeth of the second cutter into the tooth spaces of the first cutter being limited, the teeth on at least one of said cutter members being relieved along substantially their entire profiles rearwardly of their cutting edges to prevent contact of the teeth of the two cutter members except at their cutting edges, the cutters being arranged so that a plurality of first cutter teeth penetrate tooth spaces in the second cutter simultaneously.

Claim 11

A pair of cutting members for use in a granulating device comprising: a first rotatable, generally cylindrical cutting member having a plurality of helically arranged teeth, at least a portion of which are of a predetermined hand and arranged along its ouTer periphery at a predetermined helix angle relative to a plane passing through the axis of the cutter member; a second rotatable, generally cylindrical cutting member having a plurality of helically arranged teeth adapted to be positioned in driving meshing engagement with the teeth on said first cutting member the teeth on said second cutter being of an opposite hand and of an equal but opposite helix angle relative to the teeth which they engage on the first cutter member; said teeth on each of said cutters having cutting edges which are adapted to cooperate to shear material fed into their bite and to transmit driving motion of said second cutter members to said first cutter member, said cutting edges being defined by the lines of intersection of a side profile of each of said teeth with its outer periphery, said teeth on said second cutter member having tips which are of a thickness measured along a circle at their maximum depth of penetration into the tooth spaces of the first cutter member of no more than 40 percent of the distance between corresponding points of adjacent teeth on the same circle, the penetration of the teeth of the second cutter into the tooth spaces of the first cutter being limited, the teeth on at least one of said cutter members being relieved along substantially their entire profiles rearwardly of their cutting edges to prevent contact of the teeth of the two cutter members except at their cutting edges, the cutters being arranged so that a plurality of first cutter teeth penetrate tooth spaces in the second cutter simultaneously.

Claim 12

A pair of cutting members in accordance with claim 9 wherein the teeth of said second cutting member are of less thickness than the teeth of the first cutting member at any point of equal penetration of either into a tooth space of the other, said second cutting member being smaller in outer diameter than the first cutting member.

Claim 13

A pair of cutting members in accordance with claim 9 wherein the thickness of the teeth of said second cutting member on the outer periphery of the cutter is less than 20 percent of the tooth to tooth distance on the periphery.