US1318441A - Assjgknxm - Google Patents

Description

A. B. FOWLER KNIFE GRINDING MACHINE.

APPLICATION FILED DEC.8. 1916.

1 3 1 8,44 1 Patented Oct. 14, 1919.

' a SHEETS-SHEET I- 'rmz ccil'tv'nam PLANOGRAPH- co'., WASHINGTON, 01

A. B. FOWLER.

KNIFE GRINDING MACHINE.

APPLICATION FILED 0512.8.1916.

1,318,441. Patented Oct. 14,1919.

3 SHEETS-SHEET 2- I THE COLUMBIA PLANDGRAPH C0., WASHINGTON. r)v c.

A. B. FOWLER.

KNIFE GRINDING MACHINE.

APPLICATION FILED DEC.8, i916.

Patented Oct. 14:,1919.

3 SHEETS-SHEET 3.

m/ /vm/a THE animal s PLANDGRAPII- c0., WASHINGTON, Di 1:.

,ALFR'EED 'B. FOWLER, 0F BEVERLY, *MASSACH-USETTSQ ASSIGNOR, MESN'E .ASSIG'N- MENTS, UNITED SHOE MA HIFNERY CQfiPQJ-KI'ATI N, "QE'IATERSQN, NEW JER$EY,

A CQRPQRATION 0F JERSEY.

Specification of Letters Patent.

E'Patented @012. '14, 1919.

Applicationfilea December 8, 1916.. Serial No. 135,815

Tov all whom it may concern:

Be it known that 1, ALFRED. Be. FOWLER, a citizen of the United States, residing at Beverly, in the county of Essex and State of Massachusetts, have invented certainlnr provements in Knife-Grinding Machines, of which the following description,- in connection with the accompanying drawings is a specification, like reference characters on the drawingsind-icating like parts in the several figures.

This invention relates to grinding .ma chines and more particularly to machines for grinding the edges of" knives having curved cuttingedges with or without concaved faces, such, for exam-ple as the, knives used for breasting the, heels of boots and shoes, V V 1 The front or breast of the heels of boots and shoes has either a concave or a straight edge,.both styles being used, and the shank of the shoe at the junction of the heel breast is usually convex, Heel breasting knives form the breast of the heel with a concave or straight transverse surface and cut the material of the heel down to the line of the shank. The edges of such knives must be ground to conform to, the contour of the shank and, when the heel breast is concaved, they must be correspondingly curved transversely. w

VVhen this double curvature of cutting edge is to. be ground, the knife and grindingmember must not only have relative traverse in an are having a radius equal to that of the concave face of the knife but there must also berelative movementlongitudinal-ly of the knife to conform to the curvature of the cutting edge lengthwise of the knife, so as to grind the edge" at a uniform bevel and keep said curvature constant When the knife is flat for cutting a straight breast, on the other hand. there must be relative traverse of the knife and grinding wheel in a. straight line with coincident rela:

V nisrn constructed to permit relative traverse of a knife holder and grinding wheel and coincidently to. effect relative longitudinal movement and arranged to grind laterally curved and straight breasting v knives with equal facility, and in addition provides certain novel mechanism, for eflecting these results including novel and advantageous adjustment andiguiding means.

One feature-offtheinvention consists in the combination of a grinding member and knifeholding means ,cOnst-riictedand arranged for relative traverse,- with traverse guidingmeans constructed and arranged to e fl ect relative traverse along a line automatically determined by the transverse contour of- :the knife. More specifically and as .a related featuregthe knife holding means includes a knife. holder mounted for movement toward and from the grindingmember and guiding means. constructedv and .ar-' ranged tocohperate with the knife during relative traverse to conform the line of traverse to, the transverse contour of the knife Such mechanism is particularly advanta geous in that the line oftraverse automaticall conforms. to the transverse contour of t knife. edge Whether this contour be straight or curved. The automatic accommodation dispenses with the necessity of successive adjustments. for curve variance or for the change from transversely curved to.- transversely straight knives. A machine having thesecharacteristics also obviates the necessity of special equipment for transversely straight and curved knives,

,A feature of theinvention consists in the combination of a grinding member and knife. holding means constructed and1ar-. ranged for relative traverse, with a guiding member determinately and. fixedly positioned to-engage the roar face of the knife during such. relative traverse to maintain successive grindercontacting portions of the opposite knife face uniformly spaced; from said guiding member. This arrangementtendsto, secure uniform bevel of the, cutting edge. of the knife and to correct anyoriginal unevenness inthe. transverse of the cutting edge by grinding-the edge to. a uni: form bevel. 1 I

A further feature of. the invention consists in the combination of a grinding mem-.

ber and knife holding means constructed and arranged for relative traverse, with guiding means constructedand arranged to effect relative traverse in a lineautomati-.

cally determined by the transverse contour. of the knife and coincidently to eflect-bodily"- of traverse to the transverse contour of the blade but coincidently insures an invariable position for that portion of the edge of the knife which is in engagement with the grinder'to secure a determined curve and a uniform bevel along 'the shank-conforming edge of the knife by confining the line of grinding contact during such traverse to the line of such curved edge so as to present successive portions of the knife edgeat a uniform angle to the'per'iphery of the grinding'wheel. v In one embodim'ent,and as shown, a pat tern or templet' having an edge compleinental to the curve of the knife edge lengthwise of aid edge'coeperatcs with the knife holder to raise and lower the edge ofthe knife during traversing action. The templet is detachably mounted so thatdiffer ent templets maybe used for different edge curvatures.

A feature of the invention consists in the combination of a grinding wheel, a'frame positioned in coeperative relation to" the grinding wheel, a carriage guided on said frame for sliding movementtransversely of the periphery of the grinding. wheel and a knife holder mounted on and moving with said carriage and independently movable substantially perpendicularly to the line of transverse movement and'also movable toward and from the periphery of the grind in'gwheel. This construction permits of the knife curve conforming movements of the knife holder during traverse of the carriage.

A' related feature consists in" the combination with the grinding-wheel, frame, sliding carriage and knife holder mounted" on and movable withthe carriage and gindee p endently movable toward and from the periphery of the grinding wheel, of guiding means determinately and, fixedly positioned to engage and maintain successiveportions of the .edgeof the traversing knife uniformly in contact with the periphery'lofthe grind ing wheel, with; means operative to hold thev knife against said guiding means during traverslng movement of the; carriage and knife. In the construction shown, a spring holds the back face ofthe knifeagainst a frame-carried guiding member which ,main- I -tains the backo ofthe knife a uniform distance from the peripheryof't'he grinder and insures uniformity of thickness of the ground edge. In addition, the same structure is equally efficient in guiding transversely straight and curved knives since the spring will automatically move and. maintain the knife relatively to the periphery of the grinding wheel and against; the guiding member when the knife is transversely curved so as, to conform the. line of transverse movement of the knife to the transverse curvature of the knife.

, These and other features of the invention, including cert-am novel adjustment means shown in Fig; 1'; Figp3 is atop nism; and I 1 Fig. 4 is a vertical section taken on the line 44 of Fig. '1. i 1

A suitable bench 2 or other base is utilized as a support for an upstanding frame 4 supporting a grinding wheel 6 having a rounded relatively narrow periphery and driven by any suitable means, such as the pulley and belt, shown. j 1 Secured to the bench or base'2 is a' bracket 8 having a depending plate ldterminating in an elongated portion provided with a longitudinal ,slot therein and with. raised bearing faces around the edges oftheslot. A frame block '12 extends substantially'parallel withthe slotted plate 10 a nd'is formed with an offset portion 14L (Figs., 3 and 4t) extending through the slot of the plate" and plan View of the mechahaving at one side bearing faces resting" .lIO

at one end to theoflset let-by means of a screw bolt 18 and bears against'the bearing edges extending about the slot atthat side of the plate. The bracket plate 10 at its forward-'end i's formed with a'lateral offset 20 (Fig; 3) terminating "in a smooth-bored bearing sleeve 22through which extends an adjusting spindleaejthe outer end of which ispositionedat the front of the bench or support and is provided with a hand wheel 26 for manipulation by the workman. The

other end ofthe plate 16 is securedlto the offset 14;"and' is held against the bearing internally threaded sleeve 28 having a threaded stem30- entering through the plate 16 into the offset 14 of th 'frame block 12. This sleeve 2'8 is'locked tothe frame block edges of the bracketplate' by means of an by a check, nut 32. and is. carriedby the v threaded inner end ofthe adjusting spindle 24c. This spindle held against longitudinal movement. inv the bearing sleeve 22 by any suitable means: suchas collars 25 fixed t 'the, spindle at the ends of the bearingsleeve by set screws QTKsee Fig. Obi viously, rotation of the adjusting screw 2% will move the sleeve 28 longitudinally ofthe bracket plate 10. and with it, will slide the attached frame block 12 longitudinally of said bracket plate to adjust. the grinder frame. supported by'said block toward or from, the grinding wheel 6. This adjust,- Inent ,mean is utilized to, more the knife toward the grinder for initial adj ustmeng additional grinding pressure or for adjust, ment in compensation. for Wear on the grinder,v ;It may be used also to. more the knife holder away from the grinder for the. removal or insertion of a. knife.

. The forward end ofthe frame blo'ckjl2 bifureated,,a s seen, in dotted lines at 34, Fig, 3 and to receive a lug 3.6 (Figs. land 3). ex,- tending rearwardly from a threaded sleeve 38- and pivotal'ly connected to the end of the, frame, bar by a pin 40. The angular rela tion of the sleeve 38 to the frame bar 12 may.

be varied, in turn to vary the inclination of. knifesupporting parts carried by the sleeve 38 inany suitable manner. Preferably, and as shown, the sleeve 38- is provided with an offset 42, and the frame bar 12 at its end is provided with eomplemental lateral" offsets 44L having alined threaded bores therein, through which set screws 4 :6, 4' 88Xb611d to engage the'upper and lower faces of the ofiset 4:2 and support and maintain the sleeve in angularly adjusted position relatively to the frame bar 12.

A threaded standard extends vertically through the sleeve 38..and ringed threaded sleeves 52 on the standard at the upper and lower ends of the sleeve 3.8 act ascheck. nuts to lock the standard'5O in vertically adjusted.

position.

: The'upper end of the spindle is threaded into the'lojwer bar of a rectilinear framebt and is leckedin position by means of acheck nut 56. A. rod 58 extends transverselyiof the frame adjacent to its lower end and is provided witha key 60 fitting in a keyway formed in a sliding carriage in the .form of a sle'eve62 guided-by the rod 58and its keyway for straight line movement transversely of" the periphery of the grinding wheel 6 This sleeve may be manually moved lengthwise of-the. shaft 58 and transversely of the periphery of the grinding wheel by any; convenient meansi As shown, it is formed with alaterally extending ear Selto which is pivoted the bifurcated'end of a link, 66',tlie outer endof which is 'connected to oneend of a bellicrank 6.8-, pivotally mounted upon a postupstandingfmm a lateral offset 55' at the lower-edge 0f. the, frame 54. The outer end of the bell crank leverconstitutes an op.- erating handle, (Fig. 3 by means of which the, sleeve may be reciprocated upon the guiding rod 5.8.. Y

The sleeve 62,

's provided adjacent to its opposite ends with upstanding threaded bosses 7 2into which are threaded the lower ends of vertically extending guide rods/M,

on. which are guided for vertical movement screws, in an appropriate channel formed in the upper edge of a, bar 86- outwardly offset 7 from the frame 54:. The connected sleeves '16, form part of a support for the knife.

holder,v as will be seen later.

At, its. upper endthe web, 78 connecting the. sleeves. 7 6. terminates in a sleeve 88 ex tending in substantial al-inement with the.

periphery of the grinding wheel 6v and at rightangles to the complementary sleeves 7 6. Preferably the sleeve 88 is formed integrally with the sleeves 76 and the web 7.8,

This sleeve 88, supports for movement towarda'n'd from the peripheryof the grinding wheelv 6 the spindle 90 of a knife holder, the rearward or inner end of the spindle being provided with an integral laterally curved bar 92 theopposite ends of which are provided with aline'd plates 94%, having their adjacent faces channeled as at 96 (Fig, 3), to A form-seats. for the edges. of a knife, such as the heel breasting knife 9:8, best seen in Fig. 1. The: offsets 94 are provided with horizontallyextended threaded bores and knife clamping. blocks, 100, correspondingly bored, are brought into clamping engagement with the faces of the knife at its opposite sides between its cutting and its rear edges by means of clamping screws 102 having their outer ends provided for convenience with operating handles'lOa i [The sidebars ofthe frame 54am for wardly curved in the direction of the grinding wheel and centrally of the top bar of the franne. and in alinement with the periphery of the grinding wheel is a threaded sleeve 106preferably formed integrally with the frame; This sleeve serves to carry a guiding pin 108 threaded through the sleeve and having ache'ck nut 110 to lock it in. ad-

j nsted position. 2 This guide pin will be adjusted so that its forward end'will'engage the rear face of a knife clamped-between the platesJ96, 1 00 id urin rel'atlve movement of the knlfe transverse y of the periphery ofv the grinding wheel to ma ntain successive grind encontact'ing port ons of the opposite knifeface un formly'spaced from the end of the grinding pin so thata uniforr'n beveled side edges.

edge may be secured by the grinding operation. The rear face of the knife will be maintained in guided engagement with the end of the pin 108 at all times by means of a tension spring 112 having one end anchored to a'stud projecting fromsleeve 88 and having its other and rearward end secured'to a stud dependingfrom the spindle 90-." Preferably, and in order'toprevent'any flexure or yielding of the knife when under grinding pressure, bracing pins 114 are seated'in vertical sockets in the clamping plates 94' closely adjacent to the knife seat and extend upwardly beyond the holder parallel with and in contact with the rear face of the prosertion of the knife, is now moved inwardly,

through hand wheel 26,, as previously 'described', to position the knife withits' edge engaging the periphery of the grinding Wheel 6 at thebevel predeterminedby adjustment ofi the set screws 46, 48, as 'de scribed. v a v With'a knife mounted in the knife holder and. positioned relatively to the peripheral grinding edge of the wheel 6, as described, the operation of the grinding machine will betas follows: The workman actuates the hand lever 68, reciprocating the carrier sleeve transversely of the periphery of the grindingjvvheel so that the. full width of the grinding edge of the knife traverses the grinding wheel, V a o V 7 Assuming that the, supported knife is transversely concaved as shown, and that its cutting edge is also concave, the action will be as follows: Transverse movement of the sleeve 62 willmove the knife transversely ofthe edge ofthe grinding wheel, the proj'ection of theknife being coincidently varied by the raising and lowering of sleeve 88 supporting the knife holder through the actionof the templet 84 upon the roll 82. As the knife traverses the periphery of the grinding wheel, the spring 5112 will, hold successive portions of the rear face of the knife pressed against the :relatively stationary guiding 'pin,;1( )'8, the spindle 9O sliding toward and from" the periphery of thegrinding'wheel as the transverse curvature of the transversely moving l'r nife approaches or recedes from the grinding wheel periphery.l

matic determination of the line of-traverse or transverse knife movement and the lateral turning movement of'the knife the grinding wheel will be relatively narrow. s V When transversely straight or flat breast ing knives'are to be ground, (the edge of the -kn1fe, of course, being curved to conform to the shank of the'shoe), the" same parts are used Without change, the coiled spring 112 maintainingsuccessive portions of the rear face of the transversely moving knife against the roundedendof the guiding pin so that the transverse path of movement of the straight knife is in astraight line while the appropriate templet 84 will cause the projection of the knife to be varied during its traverse of the grinding wheelperiphery so as to conform with the lengthwise curvature of the' cutting edge ofthe knife, as previously described. The described con struction is therefore employed with'equal facility for both transversely straight and curved knives without any special adjust ment or changebeing necessary, the guiding means provided being arranged to cooperate with thefknife automatically to conform the line of transverse movement to the transverse contour of theguidedknife while the and determined by the knife edge curvature o and the transverse-knifecontour;

' Having thus describedmy invention, what I claim as new-and desire to secure by 'Let" ters Patent of the United States is:-

1. A machine of the class ,described,'having in combination, a grinding member and.

knife holding" means constructed and an ranged for'relative traverse to grind the edge of 'a knife, and traverse guiding means constructed and arranged to vdirect said relative traversing movement; along a line automatically determined by thecooper'ation of said guiding means with fthe transverse face of a knife mounted holding means;

a 2. A machine of the classedes cri'bed hav-j ing, in combination, a grindingmem'ber and a knife holding means supported for relative movement transversely of the grinding member, and guiding means arranged to cooperate with the knife during such relative movementto conform the line of traverse to the transverse contour of the ife.

6'5 Manifestly, in order to permit this auto-iii 3. A machine of the class described hav retain Lin-g in co'Inbination, a grinding=meifiber, and knife a holding means construeted and arranged: for movement" along straight line transversely 'of tlie grinding member; and "guiding me'ans; arranged to coeper'ate With the supported-kni-fe -during -saidi transverse movement 'ofz the lmifeto maintain successive portions o'f the edge of the transversely moving knife uniformly in manta- 51; with the surface of the grinding member.

4. "A "machine of the class describe- 1 having; *in-oombina'tion, grinding member and knife holding -mean'ssupported for relative movement transvers'ely of the grinding member and including =a knife holder mounted for independent movement toward andf-rom the grinding member, and guiding nieansarrangd-to cooperate with the sup ported kni'fe du ring' such transverse "movement automatically' to *posi-tion the knife holder I'ela' tively to theg'rinding member to conform the line of transverse knife movement to the transverse contour of the guided knife.

5. machine 'for grinding transversely curved knives having, in --combination, a grinding "Wheel of relatively narrow peripheral grinding surface, knife holding .means constructed and arranged for movement transversely of the periphery of the grinding wheel and for coincident movement to- Ward and'from saidperiphery, andfguiding means arranged to coiiperate With'one'fa'ce of the transversely moving knife to move said knife holding -means-toward "or from the wheelperiphery to maintain successive portions of the transversely curved edge of the knife unifonnly in-conta'ct with the-periphery'of'the grinding Wheel. i

6. A machine of he class described having, i'n-combination,-a grinding member and knife holding means '*constructed andarranged for relative traverse, Witha "guiding 'memberdeterminately positioned to engage the rear face of the knife during such relative traverse to maintain successive grindercontact'ing portions of the oppositeknife face uniformly spaced from said guiding member.

7. 'A machine of the class described having, in combination, a -'grinding member and acarriage arranged for relative traverse,- a knife holder moving with said carriage" and mounted for independent movement j-toWard and from said grindinga'member, afguiding member determinately and "fixedly ":positioned to engage the rear face. 'ofthe knife "during such relative traverse to) maintain successive grinder-contacting portions of "the opposite knife face uniformly spaced from said guiding member, and means ootiper- 'ating With said knife holder to maintain the rear facefl of the knife in contact with said guiding-member during such relative" trav- 8. A machinei of the' elass described having, in eembinatio a grinding Wheel er relatively narrow enphery; teen e: arranged for movement in P a straight, 1 line transversely of said wheerperiphery, lm i fe holder moving vvith said-"carriage aiid mountetl for independent movement toward and from "saidw'vheel iperiphery,-, and "ajguiding 'Inemb'er de'terminately and fixedly posi- 'tioned toengage the rear face of the kn-i'fe as it ds "moved transversely to'inaintam successive gririder-contacting jportions of the oppositekni fe"face imiformi'y spaced "from said "guiding meihberwvhereby a" uniformly groundi knife edge. is='-seeured.

9. A machine of the class described 'fhaving, in conibination, a grinding *Inember and knife holding means supported' for relative :mo-vement' transversely -of the operative face of the grinding member, and guiding means arrangedto cooperate with the knife! during such rel a-tive transverse move'ment to elfect relative traverse along "a line atitomatical ly determined by the transversecontonr of the knife, and coincident-1y 'to' efi'ectbodi-ly longitudinal proj ec-ting movementof the knife in the "path of andduring such traversing movement.

10. A machine Ofthc class described havin g in combination; a grinding "member and knife held-mg means supported for relative movement transversely of the operative face of the grinding meinbery'and' guiding means the longitudinal curvature of said edge.

'11. A -ma'chine for "grinding breasting knives having, infcombination, a grinding wheel having a relatively narrow peripheral grinding surface, knife holding-means supported for -mo'v'em'ent I transversely of L the periphery of the grinding Wheel and toward and""ffron1 said periphery, 'linife"'gn iding means e0nsitructed'and arranged to cooperate with and position the knife "holding means during such' transverse movement to 'oflect'trave-rseof'the knife along a line corresponding to and automatically determined and controlled by the transverse contonr'of the knife, and additional knife guiding means comprisingai'templet having a-:gu-icl-' ing edge -com 'iiltnnental' to the curve er the knife edge length-Wise of the edge and -ar.

ranged to cooperate ith the knife" holding means durlng its-transverse movement to effect variable bodily longitudinal projec tion of the, knife conforming to'said lengthwise curvatureof the. edge @uniformly. to

bevel said edge in grinding. v 12. A machine of the class described, having,ein combination, a 'g fil ding Wheel, ,a

relatively rigid frame, a carriageguided on said ,frame for sliding movement transversely of the periphery of the grinding wheel, and knife holding means mounted von and moving with said carriage transversely ,oi the, grinding wheel and independently and 'coincidently movable substantially perpendicularly to the line of transverse move mentand also coincidently movable toward and from the periphery of the grinding he i a,

18.: A machine vof the class described having, in combination, a grinding wheel, a

relatively rigid frame,a carriage mounted on said frame forsliding movement along a .line substantially parallel to the axis of said wheel and transversely of its periphery, knife holding means mounted on and moving with said carriage and independently pendicularly to the hue oftransverse carand coincidently movable substantially perriage move mef1t, with guiding means cooperating with the knife holding means automatically and determinately to control said perpendicular movement of the knife.

14:. A machine of theclass described having, in combination, a grinding wheel, a

relatively rigid fra1ne, a carriage mounted on said frame for stra ghtline movement "substantially parallel. to the axis of the grinding wheel, knife holding means mounted on said carriage for straight line move ment therewithandfor coincident and independent movements. substantially I perpendicularly of the line of carriage movement and substantially horizontally toward and from theperiphery of the grinding Wheel, guid- -ing means cooperating with th e held knife and withthe knife holding means automatically to position saidholdingmea-ns during straight line carriage movement to effect transverse knife movement in a line corresponding to and determined by the transverse contour of the knife, and means to V vary the perpendicular position of 'theknife relatively .to saidflcarriage, knife holding means; and grinding wheel and; arranged to engage the rear face of a'transversely moving knife to maintain successive. portions of said rear ,face uniformly spaced from the periphery of the grinding :wheel, andfmeans operative to hold the rear face of, the knife in .contact with said guiding means during traverse ofthe knife.

16. A machine oftheclass .ing," in? combination, a grinding wheel, a

relatively rigid frame, a carriage mounted on said framefor sliding movement along a straight line transversely of the periphery of said wheel and substantially parallel with its axis, and a knife holder mounted, on 'anidfmoving transversely with said carriage and supported on said carriage for ;inde pendent movements in directions substantially perpendicular to the line of trans verse' movement and transversely1 ofsaid line'of movement toward orfrom the grind ing wheel periphery. V V k V;

17 A machine of the class described hav ing, -in combination, a grinding wheel, a relatively rigid frame,a carriage mounted on said frame for sliding movement trans,-

versely of the grinding wheel periphery, and

a knife holdermounted 011 said carriage and moving transversely with-said carriage and supported for independent movement ina direction having components substantially perpendicular to the line of transverse movement and horizontally towardor from the grinding wheel periphery, with guiding means cooperating with said knife "holder arranged automatically to efiect such independent'movement of the knife'holder coincidently with transverse movement of the carriage and knife holder and in determinate relation to the lengthwise edge curve and transverse contour of the supported knifea' 18.;A machineof the class described having, ,incombination, a grinding wheel, a rel atively rigid frame, a carriage guided on saidframe for straight line movement transversely of the periphery of the grinding wheel, a knife-holder support mounted on said carriage for transverse movement with the carriage and for independent vertical ;movement substantially perpendicularly to theline of transverse movement, and a knife holder mounted in said support for transw verse and verticalmovement therewith and I for independent movement toward and from @the periphery of the grinding wheel. 7

7 '19. A machine of the class described having, in combination, a grinding wheel, a relatively' rigid frame, a carriage guided. on said frame for straight line movement transversely of the grinding wheel-periphery,.a

,- knife holder support mounted on'saidcarriage for transverse movement with the ear- I ,riage and for independent vertical move-f ment substantially perpendicular to the line 1 1,

of transverse movement, a templet arranged to cooperate with said support during transverse carriage movement determinately to effect independent vertical movement of said support, a knife holder mounted on said support for transverse and vertical movement therewith and for independent sliding movement toward and from the grinding Wheel periphery, a guide determinately positioned on said rigid frame to engage the rear face of a knife carried by and moving with said carriage and support to maintain successive portions of the cutting edge of said knife in contact with the periphery of the grinding wheel, and means to maintain said face of the knife against said guide.

20. In a machine of the class described, in combination, a base, a grinding wheel mounted on said base, a bracket supported by said base, a bar carried by said bracket and guided for adjusting movement toward and from the periphery of the grinding wheel, means for efi'ecting adjustment of said bar, and a knife supporting frame supported by and movable with said bar, with means angularly to adjust the frame relatively to the bar and to the periphery of said grinding wheel.

21. In a machine of the class described, in

combination a grinding wheel, a bracket, a 7

bar supported by and guided for longitudinal movement in said bracket, means to effect adjustment of said bar longitudinally of said bracket, a standard carried by and extending upwardly from said bar in the di- Copies of. this patent may be obtained for rection of said grinding wheel, a frame supported by said standard, and knife holding means supported on and movable relatively to said frame.

22. In a machine of the class described, in combination, a supporting bracket having a longitudinally slotted arm, a bar supported by and guided in said slotted arm for adjustment longitudinally of the arm, a threaded adjusting spindle, a connection between said spindle and bar longitudinally movable by rotation of the spindle to eflect lengthwise adjusting movement of said bar, and a knife-carrying frame supported by and adjustable with said bar.

23. In a machine of the class described, a knife holder having means to engage and clamp opposite portions of the side edges of a knife between its cutting and rear ends, and backing means arranged to engage the clamped knife beyond said holder to brace the projecting portion of the knife against distortion or fiexure by grinding pressure.

24. In a machine of the class described, in combination, a support, a knife holder slidably mounted thereon and having means to clamp a knife, a rigidly supported guide pin to engage a face of a clamped knife, and a spring connecting said support and knife holder and operative to maintain the face of a clamped knife in contact with said guide In testimony whereof I have signed my name to this specification.

ALFRED B. FOWLER.

five cents each, by addressing the "Commissioner of Patents, Washington, D. G.

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