US2390521A - Machine for sharpening cutters - Google Patents

Description

Dec. 11,1945. G. A. DE VLIEG MACHINE FOR SHARPENING CUTTERS Filed Nov. 19, 1942 5 Sheets-Sheet l INVENTOR Gcr'ard A.- .DeV/z'eg BY p cu flyh-J -u ATTORNEYS G. A. DE VLIEG MACHINE FOR SHARPENING CUTTERS Fil ed Nov. 19, 1942 5 Sheets-Sheet 2 INVENTOR Gerard A. DeVlieg BY 4 1., .JHq' A'I I'ORNE 1 G. A. DE VLIEG MACHINE FOR SHARPENING CUTTERS 5 Shets-Sheet 3 Filed Nov. 19 1942 INVENTOR Gerard A BY PM i-IuLI-m ATTORN .DgV/l'eg M G. A. DE V LIEG MACHINE FOR SHARPENING GUTTERS Dec. 11, 1945.

Filed Nov. 19, 1942 5 Sheets-Sheet 4 Gerard BY 4411 w r W W e l R m J N W E. V m

ATTORNEYS 1945- I G. AJ E VLlEG 2,390,521

MACHINE FOR SHARPENING CUTTER-S I Filed NOV. 19; 1942 5 Sheets-Sheet 5 INVENTQR Gerard A. Del/Hey dill 44.14. I rim ATTORNEY a cutter to be sharpened. taken along the line 5 of,

closure but aim' to Patented Dec. 11, 1945 UNITED STATES PATENT OFFICE FOR smaranmdcv'rmas Gerard A. De Vlieg, RockforlL'llL ApplicationNovember 19, 1942, Serial No. 468,189 8 Claims. (o1. 51-127) This invention relates to the sharpening of rotary cutters and more particularly to those in which the cutting edges have an irregular contour such as a plurality of tapers spaced apart or of diflerent inclinations relative to the rotational axis The general object of the present invention is to provide a novel apparatus for positively controlling the positional relation of a grinding wheel and a cutter during sharpening of the latter so that the cutting edges may be sharpened to aselected clearance angle and located with extreme precision, both radially and axially whereby to eliminate the necessity of hand stoning as has been the practice heretofore in finishing sharpening such cutters.

Still another-object is to provide novel means for selecting and establishing the clearance and relief angles to be formed on the cutter teeth.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which Figure 1 is a fragmentary perspective view of a machine for carrying out the present invention.

Fig. 2 is afragmentary plan view'with certain of the parts broken away andshown in section.

Fig. 3 is a section taken along the line 3-3 of Fig. 2.

Fig. 4 is an enlarged fragmentary longitudinal section of a portion of the grinding element and Fig. 5 is a section Fig. 2. I

Fig. 6 is a section taken along the line 5-8 of Fig. 5.

Fig. '7 is a section Fig. 2.

Fig. 8 is a fragmentary sectional view of a temporary set-up for gauging the location of a cutting face of a cutter to be sharpened.

Fig. 9 is an end view of a work piece on an enlarged scale showing the angles of various surfaces in relation to the grinding wheel.

Fig. 10 is a side view of the cutter.

While the invention is adapted to facilitate the accurate sharpening of a wide variety of tapered or form cutters, it is illustrated in the drawings and will be described herein as applied to the formation ofthe clearance faces II on the teeth I2 01 a reamer I 3 which has cutting edges i4 taper'ed relative to the longitudinal axis of the tool. It is to be understood that I do not intend to limit the invention by such exemplary distaken along the line 1-1 of desired angle 1, and each .relief face ll of somewhat alternative constructions, methods, and uses falling within the spirit and scope of the invention as expressed in the appended claims.

The cutting edges ll ofthe reamer selected for illustrating the invention are formed with two different tapers a and b inclined at different angles relative to the longitudinal or rotational axis of the cutter and adapted to ream a chamber of corresponding contour in a work piece. To provide proper rake or hook r. the cutting face l5 of.each tooth l2 lies in apla-ne I which is offset laterally from the cutter axis a distance 2 (Fig.9) determined by the amount of the rake which in this instance is about 10 degrees. The clearance faces or lands II also may be of any tooth is formed with a greater inclination 0.

The present invention contemplates a positive control of the positions of and relative movements between the reamer l3 and a grinding element in the form of a rotary wheel III in such a manner that the clearance faces II and therefore the cutting edges are formed with great accuracy in relation to the reamer axis. The procedure of sharpening the reamer involves mounting the latter and wheel i8 with the active wheel surface l9 intersecting the planeiof' one cutting face ii at the clearance angle f, relatively moving the wheel and the reamer longitudinally of the reamer axis while'simultaneously moving the reamer and wheel relative to each other transversely of the reamer axis and parallel to the cutting face l5, and positively controlling the extent of said the intersection of said cutting face and the wheel surface along a line determined by the taper or contour to which the edge It is to be sharpened.

The reamer I3 is supported in a fixture mounted on a carriage 20 which is slidable longitudinally along dovetail ways 2| formed on the top of a base 22 and defining the direction of the relative longitudinal movement above referred to.

cover all modifications :and 5s travel. By

In this instance, reciprocation is effected manually by turning a hand wheel 23 (Fig. 1) which is connected transverse movements to locate by suitable gearing to a rack 2C on the carriage. The grinding wheel l8 which is be adjusted around a vertical axis adjusted axially and dressed so that its active face will be spaced accurately from the axis of the cutter being sharpened. In order to utilize the flattest portion of the ellipse of projection of the wheel face l9 as the active sharpen area,

the rotational axis I8 of the wheel is inclined relative to the plane I6 01' the cutting face I and intersects the latter adjacent the face.

In the present instance, the transverse movement above referred to is effected by moving the cutter laterally of the grinding wheel face. To this end, the cutter is supported at opposite ends and accurately centered by points 38 and 3| (Figs. 2 and 5) respectively carried by a tailstock 32 and a headstock 33 both of which are mounted on opposite ends of an elongated hollow arm 34 which is swingable about an axis 35 spaced beyond the shank end 36 of the reamer. Through a hand wheel 31, the point 38 may be adjusted axially on the tailstock which is slidable along ways, 38 on the arm 34 and may be fastened in any position by tightening a clamp 39.

The tapered end 48 of the headstock point 3| (Fig. 5) is received in the hub 4| of a disk 42 which is clamped by screws 43 against a surface 44 on an inturned end portion 45 of the supporting arm 34. The latter forms a yoke which supports anti-friction bearings 46 receiving the ends of a pin 41 that defines the pivotal axis 35 and extends through a head 48 on the end of a tapered shaft 49 which is journaled in bearings 58 on an upstanding post 5| of the carriage- 28. Caps 52 on the yoke 45 and bushings 53 (Fig. 5) between the head 48 and the bearings 46 serve to position the yoke axially of the pivot pin. Thus, the arm 34 is mounted to swing laterally about the pin axis 35 and is also adapted for adjustment about the axis of the shaft 49 which intersects and is perpendicular to the pin axis and in one position of the arm 34 is alined with the cutter axis. A split-ring 54 encircling the head 48 and connected to the post 5| by a pin 55 may be contracted by tightening a hand screw 56 to clamp the head to the post and thereby hold the arm 34 against turning about the longitudinal axis defined by the shaft 49.

Provision is made for supporting and guiding the other end of the arm 34 as the latter is swung about the pin 41. For this purpose, a roller 51 (Figs. 1, 2, and 3) is rotatable on a pin 58 supported by a post 59 in alinement with the shaft '49. The roller projects into a slot 68 in an inturned end 6! of the arm 34 and bears upwardly against .the surface 62 which is disposed perpendicular to the pivot axis 35.

Means is provided for establishing a plurality of different selectively adjustable angular positions of the cutter I3 relative to the supporting arm 34, each corresponding to correct position which one tooth I2 of the cutter is to occupy during formation of its clearance face II thereon. Herein, this means comprises a plurality of lugs 65 (Figs. 1, 5, 6, and 7) rotatable with the cutter but individually adjustable about the cutter axis, each lug being engageable in one direction of rotation of the cutter with a stop 66 which is adapted to yield and permit passage of a lug v moving in the opposite direction.

In the present instance, each lug 65 lies against the face of a two part disk 61 fitting against and clamped by bolts 68 to the hub 4| (Fig. 5). This disk has formed therein an annular T-slot 69 receiving bolts 18 whose heads are seated in the lugs 65 and adapted to be tightened to clamp the lugs in adjusted positions. The inner end of each lug flts against the periphery of a flange 1| on a cap II which is fastened by screws 12 over the hub 4| and the point 3|. A shouldered sleeve 13 connected to the cap 1| by a clamping nut 14 is slotted longitudinally to receive a pin 15 projecting laterally from a coupling 16 which receives the reduced end 11 of the reamer and thus provides a driving connection between the reamer it will be observed that the next mg 65 will engage the stop and thus establish a definite angular position of the next reamer tooth which position is predetermined by the angular adjustment of said next lug 65. To hold the reamer in a selected position during setting of each lug 65, the disk 61 may be clamped temporarily against the supporting arm 34. This is accomplished by turning a hand lever 83 (Figs. 2 and 6) projecting from a nut 84 on a screw 85 which projects through the inturned arm end 45 and has a head 66 overlapping an annular shoulder 81 on the disk 61.

To enable the work supporting arm 34 to be set in different angular positions for determining the angles of the clearance surface II and also the relief surface I1, lugs 98 and 9| (Figs. 1 and '7) are adjustable along a slot 93 in a sector 94 which is rigid with and projects downwardly from the arm 34 and is backed by a surface 95 on an upstanding bracket 96. The latter is clamped against the front wall of the base 22 by T-bolts 91 which are adjustable along a slot 88. Screw clamps hold the lugs 98 and 9| in adjusted positions along the slot 93, and the lugs are engageable with a stop pin 98 projecting laterally from the bracket 96. When the arm 34 is swung upwardly to bring the lug 98 against the pin 98 as shown in Figs. 1 and 7, the arm 34 and the reamer will be positioned relative to the wheel for grinding of a clearance facev II at an angle indicated on a scale I88 (Figs. 1 and 6) formed on the clamping ring 54. During setting of the lugs 98 and 9| or to hold the arm 34 with one of the lugs against the stop 96, the sector 94 may be clamped to 'the bracket 96 by tightening a clamping nut I8 During setting of the cutter supporting arm 34 for the desired clearance angle, the arm 34 and the sector 94 are clamped together. Herein, this is accomplished by turning a hand screw I28 (Figs. 1 and ,7) journaled on a lug I2I on the sector 94 and threading into a nut I22 which is slidable in the lug and has a pointed end I23 adapted to enter a complemental notch I24 on the arm 34 as shown in Fig. 7. By turning the screw reversely, the point may be backed out of the notch to disconnect the arm 34 from the sector.

In accordance with .the present invention, lateral swinging of the arm 34 about the axis 35 during longitudinal movement of the cutter along the wheel I8 is controlled positively by a cam pattern or template I82 (Figs. 2 and '7) having a cam surface I83 divided in this instance into sections ac and bb which accurately correspond as to taper to the edges and b to be formed on the reamer teeth but which may be somewhat longer than the corresponding reamer tapers. In the present instance, the template is simply an accurately formed plate supported on theledge I04 and lying against a block I which rests on the ledge and fits against guide surfaces I08 and I01 formed inside of the arm 34. Manually releasable screw clamps I08, hold the block I05 in position on the arm 34. the block overlies one end of the template and the other end is held in place by a screw actuated clamp IIO-.

The cam surface I03 is engaged by the knife edge III (Figs. 2 and 7) of a follower H2 in the form of a hardened block fastened .by a screw I I3 to the upper end II 4 of the adjustable sector 84. The cam and follower are urged yleldably to- Uether so that the reamer will be moved transversely of the wheel face to produce the tooth form automatically during th longitudinal movement of the work carriage. Such engagement is maintained in the present instance by a spring II5 (Figs. 2 and 3) stretched between the end of the stationary pin 58 and a sleeve- II6 mounted in the free end of the arm 34 foraxial adjustment to different positions to tensionv the spring as desired. The relation of the cam I02 and its follower II2 may be adjusted longitudinally by turning a hand crank II! on a shaft II8 (Figs. 1 and 2) journaled in the arm 34 and carrying a screw I I8 which threads into the cam support-- ing block I05.

Setting of the machine preparatory to sharpening a cutter is accomplished with the aid of a gauging device shown in Fig. 8 and including an accurate dial indicator I26 fixed on the end of arod I2! which is held by a set-screw I28 in a block I28 adapted to rest on knifeedges I30.

formed on the top of and extending along the supporting arm 34. A flange I3I on the block bears against a surface I32 on the arm to locate the block laterally ofthe edges I30. The edges and the surface I32 are located precisely with respect to the axes of the supporting arm 34 and therefore bear a definite relation to the grinding wheel face. When the block shown in Fig. 8, the rod I21 projects over the reamer I3, and a movable feeler finger I33 is adapted to bear against-a cuttingface I5 on one tooth of the reamer. The setting ing zero, the cutting face I 5 of the engaged tooth will be disposed exactly parallel to the plane in which the. arm 34 is swingable about the pivot axis 35. Such setting may be effected by the use contoured reamer of the character shown, it being assumed that the cutting faces I5 have been formed previously with their planes ofiset from the reamer axis the distance e to provide the desired -r8ke angle. After mounting of the reamer on the points and 3I,- the wheel I8 is adjusted vertically so that its center is disposed above the center of the reamer in accordance with the usual I20 is positioned as A portion I08 (Fig. 2) of ance and relief angles" on the reamer teeth, the hand screw I20 is turned to project the point I23 into the notch I24 and thereby lock the arm 34 to the sector 84 with the follower H2 in proper relation to the cam I02. Then, with the nut IOI loosened to free the sector 84 and the clamp 55 loosened to release the shaft 48, the arm 34 is turned until the desired clearance angle f is indicated on the scale I 00. Thereupon. the nut II is tightened temporarily while the lug 80 is beingset against the pin 88 and clamped to the sector. The 1113 8| which determines the relief angle is set on the sector in a similar way when the arm 34 is positioned to indicate the desired clearance on the scale I00. The point I23 may then be retracted freeing the arm 34 for turning :lletween the'limits-determined by the lugs 80 and Next, the gauging device is placed on the arm 34 as shown in Fig. 8. With the clamping lever 83 loosened, the reamer is turned relative to the arm, counterclockwise as viewed in Fig. 8,. until the cutting face I5 of one tooth engages the tip of the gauge finger I33 and the dialpointer registers zero. The clamp 83 is tightened to maintain this exact relation temporarily while one of the lugs 86 is being shifted around the slot 68 against the stop 88 and locked in this position by the screw 10. The clamp 83 may then be released freeing the reamer for counterclockwise turning relative to the supporting arm 34. However, when the lug 85 thus set is again turned clockwise and v brought against the stop 68 as shown in Fig. 7, a

of the gauging device is such that with the finger I33 thus con 'tacting one tooth face and the indicator I26 read;

definite relation will be established positively and precisely between the particular reamer tooth and the direction of swing of the supporting arm 34 as well as the active face I9 of the grinding wheel. This relation is such that the plane of the cutting face I5 of the tooth is exactly perpendicular to the arm axis 35 so that the arm will swing parallel to the cutting face I5. Preferably, this same procedure is followed in setting the lugs for all of the other reamer teeth preparatory to actual sharpening.

If the wheel face I8 has been dressed to the proper contour as shown, the parts are now set and positioned for grinding or the clearance faces II on the reamer teeth; In order to locate the junction points between the different tapers with extremeaccuracy both as to diameter and axial spacing, the end tapers a on the successive teeth are first sharpened. To bring each tooth successively into operative position, the reamer is turned counterclockwise as viewed in Fig. 7 until one lug passes the stop after which the rotation is reversed to interengage the stop and lug and thus locate the tooth precisely in its correct preselected position. The same procedure is followed in positioning the successive teeth. To

practice. Next, the cam I02 is mounted in the block I05 and by adjustment of the bracket 86 along the slot 88, the follower H2 is shiftedlongitudinally of the cutter axis until the edge I II is disposed opposite the point of contact between the-wheel face I8 and the reamer tooth to be sharpened.

' To set the arm 34 for forming the desired clearbring one tooth into operative position, the reamer is turned counterclockwise as viewed in Fig. 7 and then clockwise until its previously set corresponding lug comes against the stop 66 where it is held during sharpening of the tooth. I

Now with the wheel I8 backed away from the reamer, the carriage 20 is shifted until the 7 active face I8 is disposed opposite the edge portion a.as shown in Fig. 4. Also, the cam I02 is shifted by turning the handle I" until the follower H2 contacts the corresponding end of the surface ,aa. Then, the wheel is advanced and brought into engagement with the tooth and fed to the desired depth. As, the carriage is now shifted back and forth with the follower in contact with the cam surface aa, the reamer supporting arm 34 will swing about the axis 35 in accordance with the contour of the cam surface thus sharpening the tooth to form a new taper a, as indicated by the dotted line in Fig. 4. In a similar way, the edge portions a are sharpened on each of the teeth I! successively, the lugs 85 being brought against the stop 66 successively to locate the cutting faces l5 of the teeth in the plane in which the arm 34 is moved under the control of the cam I02.

The same procedure is used in following the cam surface bb to produce the new edges 2) as indicated by the dot-dash line in Fig. 4. Preparatory to this, however, the hand wheel III is turned to shift the cam block I05 somewhat to the left so that the control by the cam surface bb will overla v the edge b being formed and thereby enable a sharp junction pin c to be formed. Several passes across the edge I) may be made and the wheel l8 fed successively to depth to locate the junction points c at precisely the correct radii as determined by suitable gauges.

It will be observed from the foregoing that the relative positions of each reamer tooth and the grinding wheel may be established with great accuracy by the' setting of the lugs 65 and that by means of the cam I02, the relative motions which produce the edges a and b are controlled positively so that all of the cutting edges are spaced from the reamer axis and formed with extreme precision, and this, for each of the various clearance angles for which the apparatus may be adjusted. The necessity of finish sharpening by hand stoning as has been the practice heretofore is eliminated and the cost of sharpening is reduced materially. Moreover, owing to the greater precision obtained, it has been found that the number of work pieces that may be produced with one sharpening'may be multiplied several times. 7

I claim as'my invention:

1. In a cutter sharpener, the combination of a member mounted for adjustment about a, fixed axis, a second member pivotally mounted on said first member to swing about an axis extending perpendicular to and intersecting said fixed axis, a headstock mounted on said second member for adjustment around an axis which coincides with said fixed axis in one position of the second memher, a tailstock mounted on said second member and coacting with said headstock to support a cutter to be sharpened, said cutter having a plurality of angularly spaced teeth, means selectively operable to locate said headstock and cutter in a plurality of different angular positions each corresponding to one of said teeth, and gauge means mountable on said second member and adapted when engaging the cutting face of one of said teeth to establish a predetermined relationship between such face and the plane in which the second member is adapted to swing.

2. In a cutter sharpener, the combination of, a member mounted for adjustment about a fixed axis, a second member pivotally mounted on saidfirst member to swing about an axis extending across said fixed axis, a support carried by said second member to support a cutter for adjustment around an axis which coincides with said fixed axis in one position of the second member, means selectively adjustable to locate said support and cutter in a plurality of different selected angular positions relative to said second member, and means operable to limit the movement of said first member about said fixed axis to a predetermined position and selectively adjustable to vary such position.

3. Apparatus for sharpening the longitudinally extending contoured blades of a rotary cutter comprising, in combination, a bed, a carriage reciprocable along said bed, a part mounted on said carriage for angular adjustment about an axis parallel to the path of reciprocation of the carriage, a member pivotally mounted on said part to swing back and forth about an axis extending perpendicular to and intersecting said first axis, a grinding wheel having its active peripheralsurface facing axially toward said first axis and spaced along said path from the second axis, head and tailsto'cks carried by said member and adapted .to support said cutter opposite said wheel surface with the rotational axis of the cutter intersecting said first axis in all positions of said member; said headstock being indexable relative to said member to present different blades of the cutter to said wheel, a cam element and a follower element engaged thereby, said cam element extending along said cutter axis and being shaped according to the contour to which each blade edge is to be sharpened, one of said elements being fixed to said member, means on said bed adjustably supporting the other of said elements for angular adjustment in unison with said member about said first axis whereby to change the angle of the clearance face ground on the cutter blade without changing the positional relation between the cam and follower elements, and means for locking said other element to said bed whereby to cause actuation of said member in accordance with the changing cam contour during reciprocation of said carriage. i

4. Apparatus for sharpening the longitudinally extending and contoured blades of a rotary cutter comprising, in combination, a bed, a carriage reciprocable along said bed, a part mounted for angular adjustment about an axis parallel to the path of reciprocation of said carriage, a member mounted on said part to move back and forth transversely of said first axis, a grinding wheel having its active peripheral surface facing axially toward said first axis, head and tailstocks on said member adapted to support said cutter opposite said wheel surface, said headstock being indexable relative to said member to present different blades of th cutter to said wheel, a cam element and a follower element engaged thereby, said cam element extending along said cutter axis and being shaped according to the contour to which each blade edge is to be sharpened, one of said elements being fixed to said member and the otherbeing supported on said bed for angular adjustment of the two elements in unison with saidmember about said first axis, and means for connecting said other element to said bed and thereby cause relative reciprocation between the elements during reciprocation of said carriage.

5. Apparatus for sharpening the blades of a rotary cutter having, in combination, a grinding wheel, a member supporting said wheel, a second member for supporting said cutter for indexing movement about the cutter axis to present different blades thereof to said wheel, means supporting one of said tudinally of said axis to said wheel, means members for movement longibers for adjustment about the cutter axis to vary the clearance angle of said blade edge, cam and follower elements coacting during said longitudinal movement to effect said transverse movement and sharpen the engaged blade to a desired contour, one of said elements being secured to said second member, and means supporting the other element for angular adjustment about said cutter axis in unison with said second member whereby to maintain a fixed relation between the elements for all clearance angles, said last mentioned supporting means being operable to hold said other element stationary.

8. Apparatus for sharpening the blades of a rotary cutter having, in combination, a grinding 7. Apparatus for sharpening the blades of a rotary cutter having, in combination, a grinding wheel, a support for said cutter, means supporting said wheel and said support with a cutter thereon for relative movement longitudinally of the cutter axis to present a blade edge to the wheel and also for relative movement laterally of the axis .to determine the sharpened contour of the blade, cam and follower elements coacting with each other during said longitudinal movement to control said lateral movement, and means supporting said elements and said cutter support for adjustment in unison about the cutter wheel, a member supporting said wheel, a second member for supporting said cutter for indexing movement about the cutter axis to present different blades thereof to said wheel, meanssupporting one of said members for movement longitudinally of said axis to present a length of blade to said wheel. means supporting one of said members for movement transversely of the axis to control the contour to which the blade edge is sharpened, means supporting one of said mem bers for adjustment about the cutter axis to vary the clearance angle of said blade edge, cam and follower elements coacting during said longitudinal movement to efl'ect said transverse moveaxis to change the angle of the clearance face ground on the cutter. blade.

8. Apparatus for sharpening a rotary cutter having blades extending longitudinally of the rotational axis of the cutter with their cutting faces oflset from this axis, said apparatus having, in combination, a rotary cupped grinding wheel. means for supporting said wheel and a cutter for relative movement transversely of said axis in a plane disposed parallel to the cutting face or one of said blades and inclined relative to the axis of said wheel, means for effecting relative movement between said wheel and said supporting means longitudinally of said rotational axis with the cutting edge of one blade engaging the face of said wheel, and means operable during said longitudinal movement to control said transverse movement and sharpen the blade edge to a desired contour.

GERARD A. DE VLIEG.

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