US2788624A - Wheel dresser - Google Patents

Description

April 16, 1957 w. J. NEwELL 2,788,624

WHEEL DRESSER Filed July 29, 1955 2 Sheets-Sheet l INVENTOIL W/u/JM J /Vfwfu Arran/frye April 16, 1957 w. J. NEWELL 2,788,624

WHEEL DRESSER Filed July 29, 1955 2 ShSBtSfShSet 2 IN VEN TOR.

W/z/AM J /VfwaL www@ ,4 T TOR/VE y WHEEL Dnnssnn William J. Newell, Lakewood, Ohio, assignor to Harris- Seybold Company, Cleveland, Ohio, a corporation of Delaware Application July 29, 1955, Serial No. 525,114

9 Claims. (Cl. 51m-238) This invention relates to improvements in wheel dressers, that is to say mechanisms for dressing to the desired contour the active surfaces of grinding wheels. This application is a continuation-in-part of my former application Ser. No. 308,761, led September l0, 1952, now abandoned.

` One of the objects of the invention is the provision of a wheel dressing attachment for a grinding machine of the type in which the tool or other work to be ground is mounted between centers arranged on a line at iight angles to the plane of the grinding wheel.

Another object is the mounting of the dressing tool on a slide which is given a slight swinging movement about a pivot point which travels lengthwise as the template produces the swinging movement.

Another object is the provision of a wheel dressing unit adapted to be mounted between centers spaced apart the correct distance to take the holder for the work to be ground, the dressing tool being disposed in the dressing unit at the same point longitudinally of the unit as the Work in the work holder, whereby the dresser and the work may be interchangeably mounted in the machine with a minimum of adjustment.

Still another object is the provision of a novel spring means for holding the slide in operative engagement with the template.

Other objects and features of novelty will appear as I proceed with the description of that embodiment of the invention which, for the purposes of the present application, I have illustrated in the accompanying drawings, in which: Y

Fig.` l is a plan view of my wheel dressing unit.

Fig. la is a fragmental detail view on a somewhat larger scale.

Fig. 2 is a transverse sectional View taken substantially on the line 2 2 of Fig. l.

Fig. 3 is a transverse sectional view taken substantially on line 3-3 of Fig. l.

Fig. 4 is a plan view of a work holder for the work to be ground by the dressed wheel, the work being shown in position thereon, and

Fig. 5 is a longitudinal section taken substantially on the line 5-5, Fig. 4.

The invention is illustrated herein as applied to a dressing attachment for a grinding machine in which the grinding wheel is dressed to a contour required for the cutters of a reaming tool. However in some of its aspects the invention is susceptible of more or less general application for the contouring of grinding wheels. In the illustrated case reaming cutters with their holder are shown by way of example in Figs. 4 and 5.

In these figures there is shown at a holder provided with center holes 11 and 12 adapted to be engaged by a headstock center indicated at 13 and a footstock center indicated at 14 respectively. The holder 10 is provided with a transverse way 15 in which is tixed by means of a screw 16 and dowels 17 a block 18 having a centering projection 19. A bar 20 provided with a recess to t atent projection 19 is mounted at the bottom of way 15 abutting block 18. This bar is clamped in position against block 1S by a plate 21 which has a hat face engaging one side of the plate and an inclined face 22 engaging a similarly inclined face 23 on the holder. The clamping plate 21 is arranged to be drawn down and toward the bar 20 by the bolt 24 having a wing nut 25, a coil spring 26 being disposed in a cavity surrounding the bolt for raising the bolt when the nut is loosened.

Cutters 27 and 28 are mounted in diagonally disposed grooves 29 and 30 formed in bar 20. Their positions in the grooves may be adjusted by backing screws 3l, and they are secured in adjusted position by screws 32 the heads of which engage washers 33 that extend into rabbets 34 formed in the cutters. The grinding wheel is shown at 35. The centers 13 and 14 may be moved t0- ward and away from the grinding wheel by conventional means, not shown. It will be understood that when the working surfaces of the cutters 27 and 28 have been ground in a grinding machine having the centers 13 and 14 and a grinding wheel 35 positioned as indicated in Fig. 4, the cutter assembly may be removed from the machine and mounted in a reaming machine, not shown, for performing a reaming operation.

Referring now to Figs. l to 3 inclusive, the same centers of the grinding machine are indicated at 13 and 14, and the grinding wheel at 35. A bar 36, hereinafter termed a track bar, preferably of the same length as the holder 1i), is similarly provided with center holes 37 and 3S to receive the centers 13 and 14 respectively. To

steady the bar 36 and prevent it from turning clockwise as viewed in Fig. 2 there is attached to the bottom of the bar an arm 39 which is disposed to bear upon the top of a rail 4t) in the bed of the grinding machine.

41 is a slide which is of inverted channel shape throughout the major part of its length, the side elements of the channel being interiorly spaced a distance suiicient to leave clearance between the slide and the bar 36, as indicated in Figs. 2 and 3. Side rails 42 and 43 are secured to the side members of the channel and. extend beneath and slidably engage track bar 36. On the side of the slide 41 facing the grinding wheel there is a projection 44 in which is mounted a diamond dressing tool 45 xed in position by a setscrew 46.

On the upper side of the bar 36 near one end thereof there is mounted a hardened bearing block 47 which is securely fastened in place by a screw 48 and a pair of dowel pins 49. Near the opposite end of the bar there is a hardened template block 50 secured in place by a screw 51 and pins 52, this block having a cam profile surface 53 on one side thereof. The opposite side of block 5t) is recessed and provided near its ends with bearing surfaces 54 against which is a ilat leaf spring 55 bears. This spring is held in place against endwise movement by projecting portions 56 of the block.

Means is provided for a slow even traverse of the slide 41 on the bar 36. This may be accomplished by the mounting of a rack 58 on bar 36 in mesh with a pinion 59 secured to a shaft (it) that is journaled in an enlargement 61 on the slide. Shaft 6d also carries a worm wheel 62 with which meshes a worm 63 pinned to a shaft 64 upon the outer extremity of which is a wheel 65 carrying a handle 66, by means of which the worm may be turned for causing pinion 59 to travel over rack 58 and thereby move the slide in one direction or the other. The travel of the slide is necessarily slow because of the gearing down provided by the worm and worm wheel drive, and hence the operation of the dressing tool is easily controlled and accidental rapid travel is presented. A slot 63 is formed in one side wall of the slide 41 and a screw 69 extends through this slot and is threaded into a tapped hole in bar 36, by means of which the travel of the slide is limited and accidental disassembly of the parts when the unit is not in the machine is avoided.

ln the upper portion of the slide al near the right hand end lthereof as viewed in the drawing there are mounted two ball bearing rollers 70 and 7l. directly opposite each. other and spaced apart a distance only slightly greater than the width of bearing block 47. it should be understood that balls or other rounded followers could be substituted for the rollers 70 and '71, the purpose being to effect line or point engagement resulting in effect in a moving pivotal mounting for the slide.

As the slide travels back and forth upon the track bar 36 these wheels roll upon the block i7 and in effect form a movable pivot for the slide. Near the Oppositeend of the slide there are mounted in the upper .portion thereof two other ball bearing rollers 72 and 73. Roller 72 runs upon the Vprofile surface 53 of template block 5t), while Vroller 73 runs upon leaf springS. The'snacing of rollers 72 and 73 is such that when theroller 72 is in'engagement with the highvpoint of the profile surface 53 leaf `spring 55 isflexed. When the Vrollers approach either end of the template block the flexing of the spring decreases, butin all positions roller 72 is held rmly against the cam surface 53.

During cndwise travel of the slide, roller 72 running on cam surface 53 causes the left hand end of the slide to move transversely, swinging the slide to a slight extent upon its pivotal mounting provided by the rollers 7G, 7l engaging the bearing block 47. The clearance between track bar Eli/sand the side walls of the slide is provided in order to accommodate this swinging motion.

As will be apparent from the preceding description, the wheel dressing unit and the cutter mounting are interchangeably carried by the centers of the grinding machine, whereby the dressing unit may first be mounted on these centers and the dressing tool moved across the face of the wheel to produce the 'desired contour andthereafter the rea-ming cutters and their support may be mounted as a unit on the same centers and the cutters may be swung about thesecenters into contact with the wheel, without relative movement of the wheel and critters along. the line of centers, for grinding them with a contour comple'men tary to the contour of the dressed wheel.

Thus a novel an'd Vhighly accurate `and efficient method of grinding roaming cutters of the type described is employed.

As is well known in the art, reai'ners of this type `(known asfloating reamers since only two cutters are used and these are mounted at opposite ends of a support bar vwhich is self centering as it is rotated within 'the hole being'reamed) 'must be 'ground with a lead angle portion, a straight portion and a back taper portion and with back clearance behind all three of these portions of the cutting edge. Accuracy in allthese respects is very important.

Heretofore the manner of grinding such cutters has been to grind each of these three portions of the cutting edge Vseparately by the manual setting of an adjustable cutter holder at `the desired angle and then the motion of the holder along the ways of the grinding machine to carry the cutter past the grinding wheel. For veach portion of the cutting edge at least two passes of the cutter past the wheel were required, with the cutter and wheel adjusted to slightly different positions, in order to get socalled primary and secondary back clearance. rfhus six distinct manual operations have heretofore been required which consume much time and necessitate a high degree of skill on the part of the operator. The possibility of errors and improper' finish is correspondingly high.

In contrast to past procedure, themethod of this invention involves mounting a dressing unit between the centers-of the grinding machine, `dressing the Ydesired contour into the face of the grinding wheel by the motion of the dressing tool along and transversely to the line of centers, and, after removal lof the dressing unit, mounting the cutters and' their support lbaron the same centers and in line with the dressed wheel and swinging the cutters into vctritait"with the wheel yto `g`rindth`inwitha cbiitoiir complementary to that of the wheel.

ln practice and as shown in the drawing the cutters are so mounted as to be spaced vertically a short distance above the line of centers so that a desired amount of radial back clearance is provided behind all portions of the cutting edge as the cutters move past the grinding wheel.

The method and device of the invention provide large savings in time of grinding, `superior surface fnishin'the reamed hole, higher ratio of feed and -less downtime of production equipment for correction of errors.

Having thus described my invention, I claim:

l. In a grinding machine, a grinding wheel, a wheel dressing unit mounted adjacent tothe wheel to be dressed, comprising a track bar with its lengthwise dimension at an angle to the plane of the wheel, a slide reciprocable on the'track bar, a wheel dressing tool -tired-in said slide, a bearing block on said bar Vnear one endthereoa template block on said bar near the opposite end thereof, said template block having a curved profile surface on One side thereof, a pair -of opposed rollers mounted on 'said slide engaging opposite sides of said bearing block to provide a-travelingpivot for the slide, a'follower-on said slide engaging said profile surface, means holding said follower in nf'sngager'nent with said profile surface during movement of the slide, and means operatively connected to'said slide for slowly traversing said slide over Asaid track bar, whereby the wheel may be dressed to a contour governed by saidprolile surface.

2. vIn a grinding machine of the typein which the work is mounted between centers, a wheel dressing unit comprising a ytrack bar mounted between said centers, a slide reciprocable on said track bar, a wheel dressing tool fixed in said slide,la bearing block mounted on said track bar near one end thereof and a template block mounted on thebar near the opposite `end thereof, said template block having a prole surface on one side land a `leaf spring on the other, -a pair of opposed rollers mounted on said slide engaging opposite sides of said bearing block to provide a traveling pivot for the slide, a second pair of opposed rollers mounted on'said slide one roller engaging saidtemplate surface and the other on saidsplin'g, and means operatively connected to said slide for moving said slide lengthwise of said track bar, whereby the wheel may be dressed to a contour governed by the profile surface sof Asaid template.

3. In a grinding machine of the type in which the Work is mounted between centers, a'wheel dressingunit comprising a track barmounted between the centers -of the machine, a bearing block mounted on the uppersurface of said track Vbar near one end of the latter, a template block mounted on the upper surface of the Vbar near the opposite end thereof, "said template block having a profile surface on one side thereof and a leaf spring supported at its lends in 'the block at the other side thereof, a slide of inverted channel shape embracing said track bar and movable lengthwise thereon, said slide carrying a pair of opposed rollers bearing on opposite sides of said bearing block and carrying a second pair of opposed rrollers bearing upon said profile surface and said leaf spring, 'a dressing tool fixed in said slide, and means operatively connected to said slide for slowly traversing said `slide`over lsaid track bar, whereby the wheel may be dressed toa contour governed by said profile surface.

4. Ina grinding machine of the type in which the work is mounted between centers, a wheel dressing unit c'omprising a track bar mounted between the centers 'of the machine, a slide reciprocable on the track bar, means at one end of the unit constituting a` pivot for thev slide Inovable lengthwise on the track bar, a template block 'mounted on the track bar"near the opposite end thereof, said template blockhavingaprole surface on vone side thereof, a leaf 'spring supported Iat its ends in the' block "at the other 'side thereof,v saidslide carrying a pair of opposed assenze rollers bearing upon the said profile surface and the said leaf spring, a dressing tool fixed in said slide, and means operatively connected to said slide for slowly traversing said slide over said track bar, whereby the wheel may be dressed to a contour governed by said prole surface.

5. In a grinding machine, a wheel dressing uni-t mounted adjacent to the wheel to be dressed, comprising a track bar with its lengthwise dimension at right angles to the plane of the wheel, a slide reciprocable on the track bar, a wheel dressing tool fixed in said slide, means at one end of the unit constituting a pivot for the slide movable on the track bar lengthwise of the unit, a template block mounted on the track barnear the opposite end thereof, said template block having a profile surface on one side thereof and a leaf spring supported at its ends in the block at the other side thereof, said slide carrying a pair -of opposed rollers bearing upon the said profile surface and the said leaf spring, and means operatively connected to said slide for slowly traversing said slide over said track bar, whereby the wheel may be dressed to a contour governed by said prole surface.

6. In a grinding machine, a wheel dressing unit mounted adjacent to the wheel to be dressed, comprising a track bar, a slide reciprocable on the track bar, a wheel dressing tool fixed in said slide, a bearing block mounted on 4said track bar near one end of the latter, a template block mounted on the track bar near the opposite lend thereof, said template block having a profile surface on one side thereof and a leaf spring supported at its ends in the block at the other side thereof, said slide carrying a pair of opposed rollers bearing on opposite sides of said bearing block and carrying a second pair of opposed rollers bearing upon the profile surface and upon said leaf spring, and means operatively connected to said slide for slowly traversing said slide over said track bar, whereby the wheel may be dressed to a contour governed by said protile surface.

7. Dressing apparatus for the grinding wheel of a grinding machine, comprising a track bar, a slide reciprocable on the track bar, a wheel dressing -tool fixed in said slide, a bearing block on said bar near one end thereof, a template block on said bar near the opposite end thereof, said template block having a curved profile surface on one side thereof, a pair of opposed rollers mounted on said slide engaging opposite sides of said bearing block to provide a traveling pivot for the slide, a follower on said slide engaging said prole surface, means holding said follower in engagement with said profile surface during movement of the slide, and means operatively connected to said slide for slowly traversing it over said track bar, whereby the wheel may be dressed to a contour governed by said profile surface.

8. The method of grinding to an accurate curved contour the working surface of each of a pair of reaming cutters which during the reaming operation are mounted at opposite ends of a support bar, comprising mounting a wheel dressing unit on aligned work supporting centers of a grinding machine having a grinding wheel adjacent the line of said centers, dressing said grinding wheel to a curved contour by motion of the dressing tool of said unit along and transversely to the line of said centers in a curved path extending across the surface of said wheel, removing said dressing unit from said centers, mounting said pair of cutters and their support bar as a unit on said centers with the working surfaces of `said cutters at substantially equal distances from the line of said centers and in xed longitudinal vposition in line with the dressed curved surface of said wheel, and grinding both cutters while thus mounted by movement thereof about said centers into contact with said wheel.

9. For use in a grinding machine having a pair of centers spaced apart a given distance vbetween which centers the work to be ground may be mounted in a given transverse plane for rocking movement about said centers in fixed longitudinal relation thereto and having a grinding wheel mounted to rotate in said given transverse plane to one side of the line of said centers; a wheel dressing unit comprising a track bar provided with mounting means at its ends spaced apart said given distance as aforesaid for supporting the bar on centers spaced apart said given distance with the lengthwise di'- mension of the bar extending along a line joining said mounting means, a templet block mounted on the track bar and having a cam profile surface, a wheel dressing tool, a mounting supporting said tool on said track bar for limited movement of the tool lengthwise of and transversely to said track bar across the grinding surface of a wheel disposed relative to said mounting means in a position corresponding to the position of the grinding wheel of the machine relative to the centers of the machine as aforesaid, a follower on said mounting in fixed relationship to said tool and engaging said profile surface, means for holding said follower in engagement with said prole surface during movement of said tool lengthwise along said track bar, and means for moving the mounting lengthwise on said track bar, whereby the wheel of the grinding machine disposed in said given transverse plane may be dressed to a contour governed by said profile surface when said track bar is mounted between the centers of the grinding machine.

References Cited in the tile of this patent UNITED STATES PATENTS 850,014 Johnston Apr. 9, 1907 1,530,357 De Jong Mar. 17, 1925 1,937,961 Hutchinson Dec. 5, 1933 2,220,647 Harley Nov. 5, 1940 2,348,354 Miller May 9, 1944 2,373,187 Johanson Apr. 10, 1945

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