US1994051A - Sugar cane cutting knife - Google Patents

Description

March 12, 1935. H.'J. B. SCHARNBERG 1,994,051

SUGAR CANE CUTTING KNIFE Filed June 10, 1931 2 Sheets-Sheet l INVENTOR i'frrman JIB. fickarnery MWM March 12, 1935. H. J. B. SCHARNBERG 1,994,051

SUGARICANE CUTTING KNIF Filed June 10, 1931 2 Sheets-Sheet 2 Patented Mar. 12, 1935 p This invention vrelates to improvements, in sugar cane milling apparatus, andmore especially to improvements in the cane cutting" knives, and the method oflholding the knives their 5 holders and for supporting the holders; 5

f Cane knives are extensively used for theshre'dding of the long stalks of :cane, beforethey enter, the crushing rolls, but during the operation many of the knife blades break off,.'close to the holder, and through bolt or rivet holes in, .the

shank of theblade, which are used for fastening the blades to the; holder, by means of bolts or rivets. s

Breakage oi the blades at these pointsfis due to the fact that the curved shaped'blades now in use renderthese blades-very much out of balance, and when the blades revolve at very high speed, 'centrifugalstresses are set up, causing; the metal to become iatigued. The broken blade moves withthe cut caneto the crushing rolls, damaging rolls and decreasing the emciency of thecrushingplant. Many'bladesbreak directly in the holder, due to striking on iron or other hard material, coming in with the cane,

' and which-cannotbe cut by the kniveswhile rotating at very high speed. v The bolts and rivets which hold the knife blades to the holder are under a; heavy shearing stress while the set is in. operation; and if they become loose, asthey often doduring operation,

the vibration set up at the ,point of blade-fastening causes the bolts 01' rivets to break, and the complete knife is-thrown into the cane before the failure is discovered; Due to the location of the rivets and bolts in the-holder, their projecting headsare dragged through thecut cane, causing an extra power consumption'..-

When one .of the blades breaks off, the whol rotating knife set: is thrown out of balance, causing the shaft on which the knife holderis mounted to become bent :due to heavy vibration, especially since it is common. practice to use one long continuous key inthe shaftfor holding18 to 21 knife holders each having-two knife blades bolted orri-veted thereto; Theamountof vibration and shaft stresses set up in the rotating element depends entirely on how much of the blade is broken off; the smaller the piece, 'the safer it is to keep the equipment in service until a new blade can be installed. In order to install a new blade, the bolts or rivetsholding theshank of the bladeto the holder have to be removed, and as there are sometimes as many as 5 bolts, orrivets, considerable time is lost,

When the'cu'tting edges ,Of the PATENT oF-F ICE blades become dull or worn the entireknife blades have to be removed "for sharpening, which requires that moved, order to unfasten the blades from the holder. 3 This requires much time, and in a cane crushing plant it is of great importance that V a minimum of timebe lost in making repairs able time is limited by weather condition.

other. objects of the invention are to improve generally the simplicity and eiriciencyfof such apparatus and to provide a device or apparatus of; this kind which is economical, durable and reliable in operation, and economical to manu-.

faeture,

" Still' other,

objectsof the invention will appear as the description proceeds; and whileherein details ofthe invention'are described and claimed, the invention is not limited to these, since many and various changes may be made without departing from'the scope of theinvennons claimed in the broader claims.

The J inventive features for the accomplishment of these and other objects are shown herein, in connection with an improved cane knife construction which, briefly stated, includes a series of, blade holders, on a shaft each holder comprising arms, and a hub,v having, a wedge face.

A side face of, each armhas a tapering recess havingundercut side walls, each recess receiv-' ing an outwardly tape'redblade-shank having side edges fitting under said under-cut walls, the innerendof the-shank having a'wedge face engaged by 'a wedge nut'heldv in wedging en,- gagement between the wedge faces of the, hub

and blade, bya bolt passing throughsaid arm' 4 and the wed e nut.

In the accompanying dr awings, showing, by,

wayof example, two blades and ablade holder, embodying my vinvention, a

Fig. 1 is a fragmental side elevation showing the shaft carrying holders and showing the blades in edge elevation; Fig. 2 is a fragmental elevation showingrthe end of the shafts and the side faces of the blades and holders;

"Fig; 3 is a fragme'ntal a holder andblade:

"Fig.4 is a fragmental sectional v the line 4-; of Fig. 3

side elevation showing iew taken on 5 I f-romj-l'it to 168'bolts orrivets have to be re- 0., during thegrinding season, because the avail Fig. 5 shows a section on the line 5-5 of Fig. 3;

Figs. 6 and 7 are respectively side and edge elevations showing another form of blade.

Fig. 8 is a sectional view, similar to Fig. 5, but showing the shank 44 of the cutter blade in Fig. 6with a double angle on its edges, when inserted in the seat of the holder.

My invention is shown embodied in a sugarcane-milling knife set comprising a knife shaft 10 driven by a motor 11 directly coupled to one end of the shaft, a flywheel 12 being carried on the other end, the shaft rotating in bearings 13, 14 adjacent to the motor and said flywheel respectively.

Said shaft 10 has a portion 15 of enlarged diameter adjacent to the bearing 13'to. form a stop, and a taper 16, adjacent to, and tapering away from said stop. Jam nuts 18, 19 are respectively received on reversed threads 20, 21 near the other end; and two spiral series of short longitudinal key seats 23, 24, 25, 26 extend between/said taper and threads.

A plurality of contacting one- piece blade holders 27, 28, 29, are carried on said shaft and clamped between said stop 15 and a collar 30 against the nut 20. Each blade holder comprises a pair of wide transversely disposed radial arms 27, 28, and a short hub 29, the hubs having flat end faces 32 (Fig. 4) engaging the adjacent hub 29, collar 30 or stop 15, and a central opening 34 received on said shaft and having a 1ongitudinal key seat 33 (Fig. 4), the two end hubs having tapered openings fitting on the shaft taper with a forced fit.

Blades 35 are mounted on said arms as will be explained. I

As stated, said shaft has a pair of helically arranged series of longitudinally disposed key seats 23, 24, disposed 25, 26 spirally in opposite directions toward the middle part of the shaft. Short keys 36 in said seats 23 to 26 and 33 (Fig. 4) key said holders to the shaft with the axes of the blades arranged in two helical series of opposite direction, adjacent arms .27 or 28 being here shown advanced 18 degrees apart, as indicated in Fig. 3, and the number of blades being ,such that the blades of each series are evenly spaced, thereby to distribute the load evenly throughout the cycle of the shaft, said series having helical directions tending to bring the material to the middle part of the shaft to prevent clogging at the ends of the shaft. Obviously a different number and angle for the blades may be used if desired.

Said hubs and stop 15 are provided at their adjacent faces 32 with radial bores 37 (Fig. 3) each having its axis substantially in the the plane of said faces, the bore terminating short of the large opening of the hub and receiving a pin 38 (Fig. 1) fitted tightly in each bore, the material adjacent to the bore being peened over the end of the pin to hold the pin inplace, whereby said hubs are locked together and transmit twisting strains to said stop 15.

Diagonally opposite side faces of each pair of arms 27, 28 are each provided in its wide face with a wide shallow outwardly tapering recess 40 (Fig. 4) having undercut straight side walls 41 (Fig. 5), a wide fiat floor 42, and a transverse outwardly beveled end wall 43 (Fig. 3) forming a continuation of the taper of the hub. Each blade 35 is wide, relatively thin, substantially radially disposed with its center of gravity substantially in its radial axis, and made preferably principally of mild steel, and comprises an outwardly tapered imperforate fiat shank 44 seated in said recess, and a widened active portion 45 having therein a plurality of openings 46 forming one or more divergent legs 47, 48, 49, and hardened steel welded to the active edge 50, 51 on the active portion form cutting edges.

The cutting edge 50, 51 is forwardlyintermediately curved, as at' 50, and gradually extending back, as at 51, to approximately coincide for a considerable distance with the path of revolution of the extreme outer part of the edge.

The side edges 53 of each shank outwardly converge and are beveled to fit under said undercut edges 41 of. the recess, whereby, in operation, centrifugalforce' on the blade wedges the shank between the undercut edges 41 and flat against the floor 42 of the recess.

{The inner end edge 55 of the shank is disposed substantially perpendicular to'the axis of the shank and terminates short of the inner end 43 of the recess to'form'a'wedge-receiving space 56, the edge portion 55 being beveled toward the floor of the recess, to' form a wedge face 57. A lug 58 (Fig. '7) is integral with or welded on the exposed face of the shank to form a continuation of said wedge face 57 at the radial axis of the shank. A Wedge nut 60 (Figs. 3 and 4) in the middle part of 'saidspace 56 wedges between wedge faces 61 (Fig. 4) and 57 of the hub and blade. The holder arm is provided with a radially slightly "elongated bolt opening 62, registering with the, wedge-nut opening, loosely receiving the bolt 63 having a large diameterthreaded portion 64 received by the threads of the wedge nut forclamping said wedge nut into wedging engagement with said wedge faces for forcing the shank tightly between the under-cut edges of the recess, to prevent vibration.

The end of said bolt 63 has a reduced diameter portion 65 having threads reverse to, and of less pitch than, the-threads of-the larger-portion and receiving a lock or jam nut 66 engaging the wedge nut.

The end of the spaces 56 arevacant, and the floor thereof is provided'with large-openings 68 in approximate alinement with bolts '63 of adjacent arms and positioned 'to facilitate the removal of the nuts and bolts from said adjacent arms.

As stated, the shaft 16 is provided with a separate key 36 for each blade holder, the keyway being cut in such manner, that when the holders are mounted on the shaft, the holders will be preferably about 18 degrees apart, and will form a helical series up to or from the center of the shaft,-so that during operation the load on the shaft is constant, because the. knives will cut cane throughout the entire cycle.

Because of the independent keys 36 for the holders, it ispossible to fit the holders much better to the shafty'and after the holders have all been mounted, they are drawn tight together by means of the large right hand nut 18, which by means of the left handed, nut 19 is locked, to prevent the holders from becoming loose on the shaft.

After everything has been drawn up tightly, the hole 37 is drilled between the first holder and the shoulder onjthestop, and between every pair'of, holders; and the round pin 38 is fitted tightly into each hole, set slightly below the surface of 'the'metal, and the'edge ofthe metal 1;ee4;o51" I t of the cane," the shank :end of. the blade .re-

is peened over, so that the "centrifugal -force cannot throw the pins out during operation.

method of fastening locks theqholders together like a solid unit; and should any I of the knives hit a piece of iron coming in with the much finer, and the finer the cane stalks are-cut up, the higher will be the sucrose recovered from the cane.

Each holder is'so constructed, that can hold two knives, ;mounted opposite to "each other, making each holder unit perfectly balanced. Because of the tapering recess 40, any outward movement of the blade radial to the shaft will force the blade tighter into the recess especially during operation, when centrifugal force will hold the blade tightly in the holder. This makes it "impossible for any vibration to be set up bei tween the knife blade and the holder and no breaking of a knife blade at this point will take place. The shank of the blade is not drilled, and

therefore no breakage of' the blade can take place through bolt or rivet holes.

The bolt 63 for holding "the wedged nut is provided with a right hand thread'yten 'threads per inch, and a left hand thread of nine threads per' inch. This is done to prevent the bolt from becoming unscrewed from the wedged nut. The wedged 'nut having a right hand thread; .is locked tight by the lock nut 66, which has left hand threads of greater pitch; and *when there is a tendency for the bolt 'tounscrew from the wedged nut, it will be drawn up tighter, on the left 'handthread lock nut. It will not be possible to remove the bolt from the wedge nut without first removing the left hand threaded lock nut.

The bolt hole 62 in the knife holder is radially elongated, and if there-is any-wear in the taperedv the bolt can follow outwardly, by action of the 7 centrifugal force, while the equipment is still in service rotating at high speed. Tightening upon the bolt 63 while the equipment is out of service, will also cause the wedge nut to compensate such wear. v The blade shanks 4i of both types of blades, as shown in Figs. 3 and 6 may have-their edges 53 tapered on both sides, best indicated in Fig. 8 where the double tapered edges are shown. This form of edge permits of reversing the "blades in the bracket tapers 41, when desired without any" appreciable loss of. strength. 7

The knifeblade is'shaped so that during opera'tion it is practically balanced, the center of gravitybeing almostexactly in the center 'line of the blade, radially to the center of -the shaft. This condition prolonges the lite of the blade.

--I-n order to reduce the centrifugal stresses set up in the shank end of the blades, part of the material has been cut out of the-blade as at 4:6, in' order to reduce the weightiand for other purposes herein stated. Usually heretofore the material used for cane knives is of steel, so

that it can :be tempered at the cutting edge i where allwthe wear takes .p'lace'idue. toicntting: v

maining soft. Due to the width :of the material where the temper is drawn, very often cracks develop in the material, on account .of uneven cooling; and to'prevent this,..I cut some of the material-out :of the blade thus forming a .number=of legs in the blade, whichmakesiit possible to temper the blade, without cracking it, the legs 47,48, 49 in the blade being free to Jadjust' themselves to any expansion, or contraction while the'cutting edge is being tempered.

This 'c'onstruction also makes it safely possible, to use a veryrnild steel for cane, knives, and to use only for the actual :cutting edge a hard steel which'is welded to the legs .in the .blade, 'withoutfdanger of setting up shrinkage stresses at the points where the hard steel is joined to the soft-steel. This construction greatlyreduces the cost of the blades," :as onlythe cutting edge will "have to be renewed after; it has wornout. L 7 Should the-blade --strike on a piece of iron or other hardsubstance during the regular operation, a fracture would take place in the weakest ;sectioniof the knife,v which is in the outer ends of the legs; and should the cutting edge bleak at this point, only a very small piece of the knife would be thrown intothe cane, and

thebalanced condition of the rotating set would .not be much disturebd, neither would there-be much damage done "to the crushing rolls, when,

the small piece of blade passes through with the can'e.

holders on the shaft, my new construction makes it very easy t'o'get to the broken blade renew it quickly with another blade.

sary to remove a bolt completely from hold-f er, the bolt can be removed by passing it through a h'ole in the adjacent holder. This makes it'possible to mount the holders in ahelical "series-on the shaft.

The location of the bolts in the holder is such,

. Due 'to'the setting and fastening the 'blade' that at no timedo the heads drag through the cane; only the smooth shaped end of the holder does this. This reduces the power consumption greatly and thek'nife set operates much more smoothly.

'In ordertoget more service but of the cutting "edge ofthe'cane knife blade, the curve of the cutting edge is such that the angle between the cutting edge 51 of the blade and the circle the cutting edge describes in a'revolutionis :very small and .very long. r

The blade 35 (Fig. 6) can also be constructed with a double cutting edge 50, 50" so that :one

cutting edge dragging through the cut cane be I side can be cutting while the other. is dragging 3 ing the direction of the blade without reversing the direction of rotation of the shaft.

- I claim as my invention:

1. In combination, a holderhaving a recess having undercut outwardly converging side walls and an inner end wall having a wedge, face; a blade having a shank, the side edges of said shank fitting under. said under-cut walls of the recess, the inner end edge of the shank being formed with a wedge face; a wedge nut wedging between said wedge faces; the holder being provided with a bolt opening registering with the wedge nut opening; the bolt in said opening having a threaded inner portion received by the Wedge nut for clamping said wedge put into wedging engagement with said wedge faces, said bolt having a reverse threaded outer portion; and a jam nut on said outer portion engaging the wedge nut.

2. In combination, a: shaft; a series of blade holders on said shaft having arms, the arms being near each other and arranged in a helical series; a blade carried by each arm; means holding the blade on the arm comprising a nut,

and a bolt longitudinal to the shaft; each arm having a vacant opening substlantially alined with the bolt of the adjacent arm, to facilitate insertion or removal of said bolt. 7 V V 3; In sugar cane milling apparatus, in combination, a cane knife set comprising a knife shaft; a motor directly connected to one end of the shaft and a pulley carried on the, other; bearings for said shaft adjacent to the motor and said pulley; said shaft having a portion of enlarged diameter adjacent to the bearing at the motor end, to form a stop, sets of relatively,

4. In a cane cutting apparatus in combination with a shaft, a hub rigidly carried by said shaft and having at opposite sides thereof wedge faces, Opposed arms extending from said hub at said faces and having outwardly tapering recesses therein, a blade for each arm, said blades having expanded inner ends disposed in the respective recesses, wedge faces on said ends. opposite the first mentioned faces, bolts having wedge nuts disposedbetween said opposite faces, and bolt stems turnably engaging said nuts for drawing the latter inwardly whereby to urge said expanded ends into said recesses.

5. In a cane cutting device comprising a hub havingan arm extending therefrom, said arm having therein an outwardly tapered recess and said hub having an inclined face at the inner end of said recess, said arm having also therein and at the base of said face an elongate aperture, a blade disposed in axial relation with said arm and having an inner expanded end which is disposed in said recess, another inclined face on the last mentioned end and disposed opposite the first mentioned face, a bolt including an axially movable wedge nut and having faces slidably engaging said opposed faces, and a threaded shank turnably mounted in said nut and slidably movable in said aperture, whereby on turning said shank said nut may be drawn inwardly to urge said expanded end intolocking engagement in said recess.-

6.,In a cutting device in combination with a hub having an arm extending therefrom, said arm having therein an outwardly tapered recess and said hub having an inclined face at the inner end of said recess, said arm having also therein and at the base of said face an elongate aperture, a blade disposed in axial relation with said arm and having an inner expanded end which is disposed in said recess, another inclined face on the last mentioned end and disposedopposite the first mentioned face, a bolt including an axially movable wedge nut and having faces slidably engaging said opposed faces, a threaded shank turnably mounted in said nutand slidably movable in said aperture, whereby on turning said shank said nut may be drawn inwardly to urge said expanded end into: said'recess, said shank having thereon a reduced threaded terminal, and a lock nut for said terminal.

'7. In a cane cutting apparatus comprising a shaft having a hub rigid therewith and including an arm which extends from said hub,'a metal blade having its inner end mounted on the outer end of said arm and including adjacent the latter a reduced portion, a terminal band of hard metal having a cutting edge thereon, andspaced legs'extending outwardly from said portion and integrally carrying said band.

3. A cane cutting apparatus including in combination a shaft, mutually engaging flat hubs mounted on said shaft, opposed arms extending from each of said hubs, means holding said hubs individually on the shaft so that said arms point in different radial directions, each of said arms having in its inner end and onfan are having its center on the axis of said shaft openings, blades having their inner ends engaged on the outer ends of said arms, and means carried by the first mentioned ends and holding the inner ends of said blades in the engaged position, said means including fastening elements which are disposed between the openings of the respective arms, so that parts of said elements may be disposed in the opening of adjoining arms. 7

9. Ina cane cutting apparatus, the combination of a revolvable hub having opposed arms extending therefrom, each of said arms having at its outer end a relatively long tapered recess the lateral boundary faces of which are undercut, each of said arms having also therein a screw receiving aperture; a blade carried by each arm and including an inner end having a short expanded portion which is provided with lateral beveled edges, so that said portions may be freely placed in the inner ends of the respective recesses and then moved outwardly, whereby to engage said edges against said faces; and means for holding said edges in the engaged position, said means including a screw in each aperture.

10. In a cane cutting apparatus, the combination of a;revolvable shaft, a hub rigid with said shaft and having opposed arms expanding therefrom, each of said arms having at its outer end a relatively long outwardly tapered recess the lateral boundary facesof which are undercut, each of said arms having also therein a screw receiving aperture; a blade carried by each arm and including an inner end having a short outwardly tapering portion which is provided with lateral beveled edges, so that said portions may be freely placed in the inner ends of the respective recesses and then moved outwardly, whereby n a e i idaed esase n a clifec a d m a o -.h ld nesa ed es mine en ed p itiqm i .m s h v n s r dis os in eaohapertura-said screws-being adaptedto engage the inner ends of saidblades; 1 a v 11;.-Ina cane cutting,apparatus-the combi-- t n of rerol-v b e s t aahu wi saidflShflf-t and having opposed armsextnding 7 with lateral beveled'edges, so that said portions ma e r c d-im t i l rl w th respective recesses and thenrnovedoutwardly, whereby to engage;said;edges against said faces; saidouter end including; a forwardly curved edge carrying portion,the outer terminal part ,of which is curvedrearwardlfi and means forhold ing said edges .in-the-engaged position said means including; a-screw in each aperture, said screws being adapted tocooperatewith the inner ends of said-blades; 1

1-2, In a'high speed cane cuttinge apparatus,

ahigh speedshaft; blade holders mounted on the-'shaftand each comprisingan arm; spaced from; adjacent armsand havingja' wide out wardly tapering recess havingundercut side walls; and a radialblade each hold r-. -com prisinga shank having beveled side edges fittingunder said undercut walls. i i r 13. Inf-a cane cutting apparatusya shaft; a series-of blade holders secured on said' shaft each having a thin radial arm spaced from adjaeentar-ms and each havingawideside face having therein agwide, recess having its axis substantially radial to the shaft and outwardly pe in andh e i sis de awal sieach undercut to form a groove adjacent to the floor of the recess, the grooves outwardly converging toward each other; a blade comprising an outwardly tapered shank having its side edges fitting in said grooves; the outer end of the shank beyond the recess being narrow and the inner end of the recess being unobstructed, whereby the shank may be removed by inward and lateral movement. 7

14. In a cane cutting apparatus, a shaft; a series of blade holders secured on said shaft each comprising a hub on the shaft and a thin radial arm, each arm being spaced from adjacent arms and-having a wide side face perpendicular to the shaft; a side face on each arm having a wide recess axially radial to the shaft and outwardly tapering and having undercut side walls giving to the recess a dove-tail shaped cross-section perpendicular to the axis of the recess; a blade comprising an outwardly tapered shank having beveled side edges fitting under said under-cut walls; the taper and bevel of the recess and shank being such that the shank, when wedged in place by centrifugal force is held against outward or lateral movement relative to the recess, and is wedged by the underout Walls against the floor of the recess.

15. In a cane cutting apparatus, a shaft; a series of blade holders each comprising a, hub on the shaft, and a thin radial arm each having a wide side face'substantially perpendicular to the shaft; said side having a wide recess having 1 its axis radial to the shaft and having outwardly the holders are secured in place.

9% f i. Sha e em t on: 9. 1 en a t t exi lof. e es b s v 29 prising an outwardly taperedshank having bev eled side edges-fitting under said under -cut I walls; releasable; means for holding the shank against inward movement in the recess toward said shaft thereby to hold the shank wedged in the recess; the I inner end of the shank being spaQedva 1distaree from I the inner endfof the reeess, and'the part of the shankand blade outwa 'dly of therecess being narrowenthan the recess; said distance andthe taper and bevel of the'recess' andshank, and thewidth of the nar rower part being such thatinward movementof the shanktoward the shaft unwedgesthe shank and allowslateral movement of the shank from the recess and such that the shank; when wedged is held against outward or lateral movement rela-tive to the recess, the arms of adjacent holders being sufficiently spaced to admit-lateral movement of the shank from thezfrecesses when 16 1pcombination;ashaftg a series of blade holders ore-said shaft having arms,- the arms I arrangedin a helical series anddisposed closely adja-cent-toform a-deep narrow recess between the-arms; blades;havin'g shanks carried by the arms respectively; andmeans holding the blade on, the ar-m comprising anutand a headed bolt at the-inner endof-the'shank; saidvnut and the belt headbeing disposed in the; deepestpart of 'theadjacentrecesses and protected by the arms aeei t d as ine ro h the e-- 151-7. Ingahigh-speedcanecutting apparatus,- a high-speed shaft; blade holders mounted on-the shaft:- anda ra'dialblade of mild steel in each holder comprising a shank firmly mountedon saidholder-pthe cuttingedge of-the' blade being intermediately curved and gradually extending back -along thepath'of the extreme outer part ofsaida edge; 3 said; blade comprising an active portion having a plurality of one or more approximately radial openings forming one or more divergent legs, and a hardened steel leg portion welded to the side of said active portion to form a cutting edge; said hardened leg being welded at its-ends only to form said opening,

thereby reducing tendency to crack at the weld;

said openings reducing the width of the'blade surface, thereby avoiding unequal cooling and cracking when the temper is drawn.

18. In a high speed cane cutting machine, a

high-speed shaft; blade holders mounted on the shaft; and a radial blade in each holder comprising a shank firmly mounted on said holder; said blade having one or more approximately radial openings forming one or more divergent legs, said blade having its largest cross section at the inner end of the shank and gradually decreasing in cross-section to near the outer end of theblade, thereby rendering the blade increasingly unlikely to break at points approaching said inner end, thereby reducing the length, cross section and weight of the broken pieces, thereby reducing eccentricity of weight and re ducing damage to subsequent parts of the machine.

19. In a cane cutting apparatus, a shaft; blade holdersmounted on the shaft; and a radial blade in each holder comprising a shank mounted in the holder; the cutting edge of the blade widened active portion having a plurality of approximately radial inwardly tapered openings forming one or more divergent legs, one of said legs being hardened steel portion welded to the forward part of said active portion'formed with a cutting edge, thereby to avoid formation of stresses, during shrinkage, at the points of the welding of the hard steel on the mild-steel.

20. In a high speed cane cutting apparatus, a high speed shaft; blade holders mounted on the shaft; and a radial blade in each holder comprising a shank mounted in the holder; the cutting edge of the blade being intermediately curved and gradually extending back to substantially coincide for a considerable distance with the path of the extreme outer part of the edge; said blade being shaped to dispose with its center of gravity substantially in the radial axis of the shank thereby to prevent twisting of the blade and fatigue-causing stresses at said shank and consequent breaking off of the blade at the shank. r 21-. In a high speed cane cutting apparatus, a high speed shaft; radial blades mountedon the shaft; each comprising a shank; the cutting edge of the blade being forwardly intermediately curved and gradually extending back to substantially coincide'for about 18 with the path of the extreme outer part of the edge; said blade being shaped to dispose its center of gravity substantially in the radial axis of the blade thereby to prevent twisting of the blade andfatiguecausing stresses at the inner 'endof the blade and consequent breaking off of the blade at the inner end. a

22. In a high speed cane cutting apparatus, a high speed shaft; blade holders mounted on the shaft and each comprising an arm having a wide outwardly tapering radial recess having undercut side walls; and a radial blade in each holder comprising a shank having beveled side edges fitting under said undercut walls; the cutting edge of the blade being intermediately curved and gradually extending back tosubstantially coincide for a considerable distance with the path of the extreme outer part of the edge; said blade being shaped to dispose its center of gravity substantially in the radial axis of the shank thereby to prevent twisting of the blade and fatigue-causing stresses at said shank and consequent breaking off of the blade at the outer end of the tapering recess.

' 23. In a cane milling apparatus, a shaft having a stop near each end; a'series of blade holders having hubs contacting each other on said shaft, end hubs of the series engaging said stops respectively; said hubs and a stop being provided at their adjacent faces with radial'bor'es forming recesses in said faces respectively; parts of the wall of the recesses being inclined to the hub faces; and a pin secured tightly in each bore, said pins tending to push the hubs apart should there be slight relative motion therebe tween, thereby tightening the hubs between the stops, thereby to distribute the strain longitudinally and tangentially of the shaft.

24. In a cane milling apparatus, a shaft having a stop near one end, and threads near the other end; a nut on said threads; a series of blade holders havinghubs contacting on said shaft, and hubs or the series engaging said nut and stop respectively; said hubs and stop being provided at their adjacent faces with radial bores forming semi-cylindrical recesses in said faces respectively; and a pin secured tightly in each bore, said pins tending to push the hubs apart, should there be slight relative motion between the hubs, thereby tightening the hubs between the stop and nut, thereby to distribute the strain longitudinally and tangentially of the shaft.

HERMAN J. B. SCHARNBERG.

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