US2780214A

US2780214A - Method and device for forming grinding wheels

Info

Publication number: US2780214A
Application number: US404220A
Authority: US
Inventors: Alfred C Page
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-01-15
Filing date: 1954-01-15
Publication date: 1957-02-05
Anticipated expiration: 1974-02-05

Description

. Feb. 5, 1957 A. c. PAGE METHOD AND DEVICE FOR FORMING GRINDING WHEELS 5 Sheets-Sheet 1 Filed Jan. 15, 1954 INVENTOR. AZ/reJ C7. g

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Feb. 5, 1957 A. c. PAGE ,7 4

METHOD AND DEVICE FOR FORMING GRINDING WHEELS Filed Jan. 15, 1954 5 Sheets-Sheet 2 INVENTOR. fl/Y'ref (I @e,

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Feb. 5, 1957 A. c. PAGE 2,780,214

METHOD AND DEVICE FOR FORMING GRINDING WHEELS Filed Jan. 15, 1954 5 Sheets-Sheet 3 Feb. 5, 1957 A. c. PAGE 2,730,214

METHOD AND DEVICE FOR FORMING GRINDING WHEELS Filed Jan. 15, 1954 5 Sheets-Sheet 4 1&4 v

. I INVENTOR. /9//rea C @e.

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METHOD AND DEVICE FOR FORMING GRINDING WHEELS 5 Sheets-Sheet 5 IN V EN TOR. fl/ reJ C. Page. I 2 n 22, 9+? I xrrrarzvX/v Feb. 5, 1957 Filed Jan. 15, 1954 United States Patent METHOD AND DEVICE FOR FORMING GRINDING WHEELS Alfred c. Page, Detroit, Mich. Application January 15, 1954, Serial No. 404,220

26 Claims. (Cl. 125-11) The present invention relates to grinding wheels, and more particularly to a novel method and means for forming or dressing the grinding surface of a grinding wheel.

In modern grinding practice, it has been recognized that both flat and round machine work can be ground with remarkable speed and accuracy to innumerable intricate as well as awkward forms by the use of a surface grinder equipped with a grinding wheel having a multiformed or contoured grinding surface. An obstacle to the unlimited use of multiformed or contoured grinding wheels is the difiiculty in forming and dressing the precision contours on the grinding wheel quickly and within reasonable costs. In the forming of contours on the grinding wheel, the basic problem involves the physical removal of material from the grinding wheel, which removal is complicated by the fundamental character of a grinding wheel. Since a grinding wheel usually consists of fine abrasive grains securely bound together by a bond of varying hardness, an ordinary cutting tool placed against a wheel is quickly worn down by the abrasive with little or no effect on the grinding wheel.

In the conventional crushing method of forming and dressing grinding wheels, a metallic crushing roll having the desired contour formed on its periphery is forced, under high pressure, against the working surface of a grinding wheel. This high pressure exerted between the members as they are forced together crushes the bonding of the abrasive particles so that a complementary shape is formed on the grinding wheel. The contour is formed on the entire periphery of the wheel by the mounting of one member for free rotation and rotatably driving the other member whereby rotation is imparted to'the first member during the forming operation.

A major problem in the use of the conventional crushing method has been the relatively short life of the precise contours on the crusher roll. This excessive wear on the crusher rolls is due largely to the slipping action that takes place between the wheel and roll during a crushing operation. The latter factor becomes apparent when it is seen that the diameter of the crusher roll varies with the ridges on its periphery. Since the periphery of each ridge is in crushing and driving contact with the grinding wheel and each portion of the ridge has a different radial speed, there are in effect various driver-to-driven ratios operating simultaneously between the two members, whereby a slipping action occurs' This slippingaction, combined with the fact that the grinding wheel is an abrasive member and the further fact that a high pressure is being exerted between the members, results in an unusually high amount of wear on the crusher roll. Various attempts have been made to lessen this wear on the rolls including the use of very hard materials for the crusher rolls, which further increases the high cost of machining the units. However, even with crusher rolls formed from such hard materials, the wear on the crusher rolls is still excessive.

In accordance with the teachings of the present invention, a novel method and means is provided for formin and dressing a grinding wheel with a crusher roll whereb the life expectancy of the crusher roll is greatly increased Under this method, the desired material is quickly an accurately removed from the grinding wheel by the re peated application of a shock or impact force to th grinding wheel, so that the bond holding the abrasiv grains is broken by the impact of the applied force rathe than by a continuous crushing action. Thus, in one em bodiment of the invention a slowly rotating crusher rol having a contoured surface is rapidly reciprocated relativ to the grinding wheel for breaking the bond of the whee at the points of contact to form the complementary con tour on the grinding surface. As a result of this impac force, the continuous high pressure otherwise employer between the members is eliminated and the harmfu effects ,of slippage are greatly reduced. Without sucl slippage, the crusher roll may be suitably formed of 1 material which is easily and inexpensively machined Furthermore, the material is quickly removed from th grinding wheel and the wheel is thus completely former in a much shorter time than is possible by the conven tional. crushing method.

Accordingly, an object of the .present invention is th provision of a novel method and means for quickly am accurately forming and dressing a contour on the grind ing surface of a grinding wheel.

Another object is the provision of an improved methot and means for forming a grinding surface on a grindin; wheel by breakage of the bond of the grinding whee with a shock or impact force.

A further object of the present invention is the pro vision of an impact method and means for forming contoured grinding surface on a grinding wheel with z crusher roll which greatly increases the useful life of tht crusher roll.

A still further object is the provision of a method ant means for forming a grinding wheel which eliminate: the need for extremely hard materials for the crushe1 roll.

Still another object of the present invention is the pro vision of a means and method for forming the grinding wheel which materially decreases the manufacturing cos of a formed grinding wheel.

A still further object of the present invention is a mean: for forming a grinding wheel quickly and accurately ant which is simple in construction and sturdy in operation With these and other objects in view, as will herein after more fully appear, and which will be more par ticularly pointed out in the appended claims, reference is now made to the following description taken in con nection with the accompanying sheets of drawings it which:

Figure 1 is a longitudinal sectional view showing a pre ferred embodiment of the grinding Wheel forming appa ratus comprising the present invention;

'Figure 2 is a frontelevational view showing a multilobed cam employed in the embodiment of Figure 1 for concentric spindle and camshaft;

Figure 4 is a longitudinal view showing a further embodiment of the instant invention which is similar in construction with the embodiment of Figure 3 but employs direct drives for the spindle and camshaft;

if Figure 5 showing means for controlling the movement f the pivoted members;

Figure 7 is a rear elevational view of Figure 5 showing he reciprocating driving arrangement for the camshaft; vnd

' Figure 8 is a schematic view of an alternative embodinent showing means for moving the grinding wheel and rnsher roll toward and away from each other, this view vlso showing in schematic fashion means for rotating the .rinding wheel and a pulsating electromagnet for vibratng the crusher roll support.

In the drawings, wherein like reference characters desgnate like or corresponding parts throughout the several 'ie ws, there is shown in Figure l a conventional grinding lheel 10, of suitable shape and size, comprising a multiude of abrasive grains secured together as a unit by a onding agent and including a grinding surface 12. The rinding wheel is mounted for free rotation upon a suitble support (not shown) which may comprise a spindle If a surface grinder or the like. Engageable with the rinding surface of wheel 10 is a slowly rotated crusher on 14 having a contour formed on its periphery which, s illustrated in the drawings, comprises a plurality of idges 16 such as are present on grinding wheels used to rind taps. As will hereinafter more fully be described, he crusher roll is rapidly reciprocated relative to the minding wheel for repeatedly applying, by the ridges 16, sudden shock force to the grinding surface 12 to form omplementary ridges in the grinding wheel. While the .ontour of the crusher roll is illustrated as comprising a wlurality of ridges for forming a precision tap grinding urface on the grinding wheel, it is obvious that the conour may have other shapes as desired.

The mechanism 18 for supporting and driving the xrusher roll 14 comprises a stationary casing or housing 20 suitably supported adjacent the grinding wheel 10, .uch as on the work table of a surface grinder or the ike, and includes a main bearing frame 22, an intermediate supporting web 24 and an enclosingend section ll'ld gear housing 26., which are suitably secured together k8 by bolting or the like to form a unitary casing. The nain bearing frame 22 is provided with a suitable upper ;hell portion 28 defining an enlarged cavity in the casng, and an upstanding bearing and base portion 32. the shell portion has an upper section thereof cut away is at 30, for accommodating a protruding boss as will iereinafter be set forth. The lower end of portion 32 s provided with a pair of laterally extending integral iange member 34 for securing the forming mechanism to 1. suitable foundation, while the upper end of portion 32 s provided with a longitudinal bearing aperture 36 there- :hrough. The supporting web 24. is provided with an .ipstanding bearing web. 338 having a bearing aperture 39 therethrough, and gear housing 26 is also provided with an enlarged bearing portion 40 having a bearing aperture 42 therethrough. Bearing apertures 36, 39 and 42 are axially aligned.

J onrnaled within the apertures 36., 39 and 42 by suitable bearings 44, 46,, 4,8 and 50. is a camshaft 52 which extends beyond each end of the casing. Fixedly mounted the outer end; of camshaft 52 is a V-pulley 54 adapted to be rotatably driven at relatively high speeds from a suitable power source (not shown) for driving the mechanism. The other end of camshaft 52 has fixedly mounted thereon a cam 96 having a plurality. of flats 9.8; and lobes 99 (Figure 2) formed around its periphery. Although the size and shape of lobes 99 produced by flats 9% may vary according to the particular requirements of an installation, the flats 98 are preferably formed with their maximum depth approximating 0.003 to 0.006 inch. As will hereinafter be described, the cam functions, to provide the rapid reciprocating motion of the crusher roll relative to the. grinding wheel;

The crusher roll 14 is 'rotatably driven by the \t-pulley 54 through a gear reduction mechanism generally indicated at 56 which is preferably of the planetary gear type. The mechanism consists generally of three interconnected gear elements, namely a sun gear 53, a locked gear 60, and a plurality of planet cluster gears 62 carried by a cage member 64 fixedly secured to camshaft 52 as by a key. Each planet cluster includes a shaft 66 journaled by bearings 68 on cage 64 and carrying, at the ends thereof, planet gears 70 and 72 of slightly differing pitch diameters. Planet gears 70 mesh with locked gear which is fixed to the end section of gear housing 26, while the planet gears 72 mesh with sun gear 58. The sun gear is in turn journaled on hearing 46 within aperture 39 and has fixedly secured thereto a pinion 74. As a result of the construction thus far described, it will be seen that rapid rotation of V-pulley 54 will directly drive camshaft 52, cage 64 and thus planet cluster gears 62. Sun gear 58 and pinion 74 will thus be driven at a slow rate compared with shaft 52, in the normal manner of planet gear reductions.

Pivotally mounted within the cavity formed in casing 20 by shell 28 is a longitudinal spindle housing 78. The housing has formed on its upper, and outer end, a boss 77 protruding through the cut-away section of housing shell 28 and carrying a pivot pin 76 secured to stationary casing 20 whereby the spindle housing may pivot within the casing. Journaled within the pivoted spindle housing and extending from the housing at each end thereof is a crusher roll spindle 82. The outer end of the spindle is formed with a reduced portion 84 having a drive gear 86 fixedly mounted thereon and secured thereto by a collar nut 33. Gear 86 is positioned in loose meshing relation with pinion 74 so that gear 86 may be driven by pinion 74 at all times while permitting slight angular movement therebetween. It will be noted that the pitch diameter of gear 86 is larger than that of pinion 74 whereby a further speed reduction is obtained. As a result of the speed reduction obtained in the gearing, cam shaft 52 is driven at a high speed while spindle 82 which carries crusher roll 14 rotates at a much slower speed.

A reciprocating motion is imparted to spindle 82 through a cam-follower arrangement comprising the rapidly rotated cam 96 and a follower 90 mounted on spindle 82. Since spindle 82 and cam 96 are rotated at greatly different speeds, follower 90 which is mounted on spindle 82 adjacent to housing 78 and in juxtaposed relation with cam 96, is preferably supported by non-friction bearings for reducing slippage and noise between these members. Because of this hearing construction, follower 90, which engages cam 96, will be rotatably driven at approximately the same speed as cam 96. At the same time, follower is rapidly reciprocated about pivot pin 76, due to its follower action, and serves to reciprocate spindle 82, housing 78 and crusher roll 14 which is carried on spindle 82.

The outer end of spindle 82, adjacent bearing 90, is formed with an enlarged mounting portion 92 which is adapted to carry crusher roll 14. Mounting portion 92 is provided with an integral annular stop flange 94 and an axially extended threaded bore 106 in its extreme outer end. Crusher roll 14, which comprises a cylindrical memher is mounted on portion 92 and positioned against stop flange 94. The roll is appropriately fixed for rotation with spindle 82 by suitable means such as a key and is locked in place by stop washer 102 and a securing bolt V 104. threaded in bore 100.

In order to control the upward movement of crusher roll 14 about pivot 76 and thus insure that the axis of crusher roll spindle 32 will not swing beyond a position in. which it is substantially parallel to the grinding wheel axis, a threaded adjustment screw 106 is positioned on the inner end of shell portion 28. Screw 106 passes through shell portion 28 and is adapted to engage a stop member 108 rigidly mounted on the spindle housing. A locking nut 110 coacts with screw 106 for locking the screw in an adjusted position.

ljuring the forming operation it is desirable to maintain constant rotation of the grindin'g'wheel through its engagement withthe slowly' rotating crusher roll in order to insure a uniform contour around the entire grinding wheel periphery. Since the crusher roll is alternately moved toward and away from the grinding wheel by the rapid reciprocating motion, there would ordinarily tend to be less rotational driving force exerted on the grinding wheel during these portions of the cycle when the crusher roll is retracted, and consequently, non-uniform rotation of the grinding wheel. To insure uniform movement of the wheel, a suitable spring 112 is placed within a pair of aligned counterbores 114 formed in spindle housing 78 and bearing portion 30 of casing 20, respectively, adjacent the lower outer end of spindle housing 78. This spring, which is seated on the stationary casing, is adjusted to exert a slight upward force on housing 78 and hence crusher roll 14 to force the crusher roll into light fric tional driving engagement with grinding wheel 11 at all times. This engagement is made such that proper functioning of the impact arrangement is not affected in any manner, and wear due to this engagement will be minimized because of such light pressure between the parts.

Pivot 76 and boss 78 are preferably provided with a suitable dust cap 116 which extends over these members and is secured to the main central frame 22 of the casing. A second dust cap 113 is suitably formed and secured to spindle housing 78 for covering the outer end of the mechanism including follower 90 and cam 96. If necessary, other protective members may be provided for the mechanism; all of which will be apparent to one skilled in the art.

Operation In the preparation of the mechanism for operation, the casing is secured in position on a suitable support, such as the work table of a surface grinder, with the axis of spindle 82 disposed in spaced, parallel relation with the grinding wheel axis. A suitable crusher roll is attached to spindle 82 adjacent grinding wheel 10 by means of washer stop 102 and bolt 1G4 and the mechanism actuated through V-pulley 54 from a suitable power source. The V-pulley is driven at a rapid speed and directly drives cam-shaft 52 for rapidly rotating cam 96 and cage 64 of planetary gearing 62. However, due to the speed reduction derived from the gearing, spindle 82 and the attached crusher roll .14 are slowly rotated. Meanwhile, because of the engagement of follower 9% with cam 96 a rapidreciprocating motion is imparted to spindle housing 78. The crusher roll 14, mounted on housing 78 is carried upward with housing 78 with each reciprocating motion and imparts a repetitive, sudden shock force to the grinding wheel for breaking the bond of the grinding wheel, and forming a complementary contour on its grinding surface.

The upward movement of housing 78 and crusher roll 14 is limited by adjustable stop 106 to a position in which the axis of spindle 82 is parallel to the axis of the grinding wheel. The contour will be evenly formed on the grinding wheel and distortions due to non-parallelism between the crusher roll and grinding wheel axis will be avoided. As the forming operation progresses, crusher roll 14 is held in light engagement with grinding wheel 10 by spring 112. This action produces ,a frictional drive such that crusher roll 14 slowly rotates the grinding wheel, whereby the grinding wheel is completely formed around its periphery.

It will be noted that in instances where it may require several revolutions of the grinding wheel to form a complete contour and wherein a small contour depth it attained during each revolution, the crusher roll and grinding wheel are moved towards each other during the form ing operation. Preferably the grinding wheel is moved downward towards the crusher roll in discrete intermittent 6 steps, and this may be done by the mechanism of a surface grinder used to support the parts.

Figure 3 illustrates another modification of the present invention for forming 'and dressing a grinding wheel. In this modification the mechanism operates in essentially the same manner as in the embodiment of Figure 1 but differs in the structural arrangement of the support and drive means for the crusher roll.

Referring in further detail to Figure 3 there is shown a grinding wheel including a grinding surface 152, rotatably mounted upon an axis (not shown) which is positioned in spaced parallel relation with the axis of a crusher roll 154. As described with respect to the embodiment shown in Figure 1, crusher roll 154 is formed with a contoured periphery and is rapidly reciprooated relative to the grinding wheel for repeatedly imparting a sudden shock force to the grinding wheel to form a complementary contour on the grinding wheel.

The mechanism for supporting and driving the crusher roll in this embodiment comprises an integral stationary casing 156 having a supporting flange 158, a shell portion 160 defining a cavity therein and a lower section 162. Carried Within a bore 164 formed in section 162 is a follower shaft 166. The right end of shaft 166 protrudes from bore 164 and is provided with a brushing 167 having a concentric follower 168 rotatably mounted thereon. Preferably, shaft 166 is provided with an integral annular flange 170 at its extreme end for retaining the follower in position. As will hereinafter become apparent, follower 163 operates in conjunction with a cam for reciprocating the crusher roll.

An elongated spindle housing 172 is pivotally supported within the cavity of casing 156 by a pivot pin 174. Pin 174 is journaled in a boss 176 formed on the spindle housing and mounted at its ends on the stationary casing 156 by suitable means. The spindle housing 172 serves to carry a concentric driving arrangement for crusher roll 154 including a tubular camshaft 180 journaled within housing 172 by suitable bearings 182 and 184, and spindle 186 journaled within camshaft 180 by a bearing 188 and an integral bearing flange 190. Each of the members 180 and 186 extend well beyond spindle housing 172 with spindle 186 protruding from the ends of camshaft 180. The left ends of camshaft 180 and spindle 186 serve to support a gear reduction mechanism in the suit.

In this modification, the same basic type of planetary speed reduction mechanism is provided as in the embodiment of Figure 1, and includes a sun gear 192, a locked gear 194 and a plurality of planet cluster gears 196 carried by a cage 198. A groove 200 is provided on the periphery of cage 198 and is adapted to function, with cage 198, as a V-pulley for driving the apparatus from an external power source. Each planet cluster carried by cage 198, which is appropriately fixed to the tubular camshaft 180 for rotation therewith, includes a shaft 202 journaled in bearings 204 and a pair of planet gears 206 and 298 of slightly different pitch diameters carried on the ends of shaft 202. Planet gears 206 mesh with gear 194 which is locked to bearing 182 and spindle housing 172 by suitable means such as a bolt 210. The other planet gears 208 mesh with sun gear 192 fixedly mounted on spindle 186 and locked in place by locking nut 212 on the extreme end of the spindle. As in the embodiment of Figure 1, it will be seen that upon rotation of cage 198. from an external power source, shaft 130 will be driven at a rapid rate compared with spindle 186 in the normal manner of planet gear reduction. In order to protect this gearing mechanism from the outside elements,

dust protectors

214 and 216 are provided which completely enclose the mechanism.

Integral with camshaft 180 and in juxtaposed relation with follower 168, is a multilobed cam 220 which cooperates with follower 168 for rapidly reciprocating crusher roll 154- about pivot pin 174. Adjacent cam 220 and integral with camshaft 180 is an annular StQp ledge 222 having a shoulder surface 224 on its outer side and an annular groove 22% formed in its inner side. Groove 228 is adapted to co-operate with an annular dust flange 230 positioned on casing 156. Shoulder 224 of ledge 222 functions to position a tubular crusher roll bearing and support member 226 on the end of camshaft 180. Support member 226 is provided on one end with an upstanding stop portion abutting the stop ledge 222 and at the other end with an inwardly extending drive portion 227. Carried on the support member is crusher roll 154. Preferably, the crusher roll is provided with an axial bore adapted to fit over the support member and mounted thereon as by thread means. The crusher roll is further locked in position against the stop portion of the support member by a lock nut 232. Member 226 and crusher roll 154 carried thereon are driven from spindle 186 through a bearing end stop 234 appropriately fixed to spindle 186 by a key and locked in position by a lock nut 236 on the extreme end of spindle 186. The

end stop is, in turn, locked to the bearing and support member by suitable means such as a pin 23%. As in the last modification, an adjustable screw 240 having a locking nut 242 is mounted on the stationary casing 156 and adapted to coact with a stop member 244 mounted on the spindle housing for limiting the pivotal movement of the housing. Also, a coil spring 246 is positioned within suitable aligned counterbores 248 and 256 located between the lower inner end of spindle housing and casing 156. The spring serves to bias the housing and crusher roll upwardly, to produce a light frictional drive between crusher roll and grinding wheel 156 for rotatably driving wheel 150 during the forming and dressing operation.

From the foregoing, it will be seen that in this modification of the invention, rotation of cage 198 by an external power source produces a rapid rotation of cumshaft 189 and a slow rotation of spindle 156. Since cam 229. carried on shaft 186 is in constant engagement with rigidly mounted but rotatable follower 168, and due to the pivotal arrangement of the driving apparatus, a reciprocating motion will be imparted to housing 156, shaft 130, spindle 186 and crusher roll 154. As a result, the crusher roll will in turn impart repeated shock or impact forces against the grinding wheel for breaking the bond of the grinding wheel at points of engagement therebetween to form the grinding wheel contour. During this forming operation, spring 246 and adjustable stop 240, will control the upward movement of the members and the frictional drive force between the wheel and roll such that the crusher roll will slowly drive the grinding wheel and produce an accurate, even, complementary contour on the grinding wheel.

Figure 4 discloses another modification of the invention. This mechanism is substantially the same as the modification shown in Figure 3 with the exception that it has been modified to permit a direct drive for both the slowly rotated spindle 186 and the rapidly rotated camshaft 189. Also, the spindle housing 172 is provided with a pivotal axis passing substantially through and normal to the spindle axis, inasmuch as the two embodiments are otherwise identical, the reference characters designating the individual components in Figure 3 have been retained in Figure 4 and it is not believed that a further description with respect to these components is necessary.

Referring more specifically to Figure 4, there is shown a stationary casing 151 having a follower shaft 166 carried in the lower end and a spindle housing 1'72 carried in a cavity in the upper portion of casing 159. concentrically iournaled in spindle housing 172 is tubular camshaft 181i and spindle 186. Crusher roll 154- is rotatably mounted on camshaft 130 and driven by spindle 186 during the forming operation. Cam 220 integrally formed on camshaft 180 engages follower 163 on shaft 162 for imparting a reciprocating motion to crusher roll 154.

' Carried on the inner ends of shaft 180 and spindle 186 are V-

pulleys

300 and 302, respectively. V-pulley 300 is secured to. spindle 186 by a key (not shown) and locking nut 212. Pulley 3th is adapted to be driven directly from an external power source (not shown) at a slow speed for slowly rotating spindle 186 and crusher roll 154. The second V-pulley 302, positioned between pulley 300 and casing 150, is appropriately fixed for rotation with camshaft 180 and is provided with bosses 304 and 306, respectively, on its opposite sides for spacing purposes. Camshaft 180 is driven directly through V-pulley 382 from an external power source (not shown) at a relatively fast rate for rapidly rotating camshaft 180. The spindle housing 172 is pivoted in casing 150 by a pair of axially aligned pivot pins 312. The pivot pins are formed adjacent the left end of spindle housing 172 and on oppo e sides of housing 172 with the axis of the pivot pins lying in the same plane as and normal to the spindle axis.

inasmuch as the remaining structure is similar to the modification of Figure 3 additional description of the mechanism in Figure 4 is believed unnecessary for a complete understanding thereof. However, it will be apparent that in this embodiment both camshaft 130 and spindle 186 are driven independently of each other at suitable speeds and that upon rotation of shaft 18 cam 221) engages followcr 168 for reciprocating housing 172 and crusher roll 154 about pivot pins 312. Crusher roll 154 therefore impinges upon grinding wheel 150 with repeated shock or impact forces to form a contour on the grinding wheel.

In each of the embodiments described thus far the crusher roll is reciprocated about an axis positioned normal to its own axis. Figures 5-7 disclose a modification of the present invention wherein the crusher roll is reciprocated about an axis positioned parallel to its own axis. Due to this pivotal arrangement of the crusher roll, an impact or shock force exerted by the crusher roll upon the grinding wheel will always be evenly distributed across the working surface of the wheel to form an even contour thereon.

Referring more particularly to Figures 5-7, there is shown a grinding wheel 400 rotatably mounted upon an axis (not shown) which is positioned in spaced parallel relation with the axis of a crusher roll 402. As in the prior described embodiments, crusher roll 402 is adapted to be rotated and reciprocated relative to grinding wheel 46% for imparting repeated shock forces to the working surface of the grinding wheel to form or dress the wheel. The mechanism for driving and supporting crusher roll 402 comprises an integral stationary casing 404 including an upstanding shell or frame 496 having an enlarged cavity therein and a base portion 403 defined by a plurality of mounting flanges appropriately located on the casing. An elongated box-shaped spindle housing 410 is pivotally supported in the cavity of casing 404 by a pivot pin 412 suitably journnled at the upper end of housing 410; Pin 412 is in turn mounted in a pair of axially aligned bosses formed on opposite sides of casing 404 and secured thereto as by lock nut 414.

Spindle housing 410 pivotally carries crusher roll 482 and its supporting and driving members including a camshaft 416 positioned in the lower portion of housing 416 and extending in a direction normal to pivot pin 412. Camshaft 416 is journaled within housing 410 by suitable bearings 418, 420 and 422 inserted in aligned. bores formed on opposite sides of the housing. The ends of shaft 416 extend well beyond housing 410 with one end terminating in a largealigned bore formed in casing 494 and the other drive end protruding through an enlarged" axially aligned bore 424 on the opposite side of casing 494. Appropriately fixed on the drive end of shaft 416 and on the outside of casing 404 is a V-pulley 426 having a t -belt 423 drivingly trained thereon. V-pulley 426 is locked on the shaft as by nut 430 and adapted to be driven at a rapid speed: from an external power source indicated at 432. The other end of shaft 416 has a cam 434 fixedly mounted for rotation therewith as by a key and locked in position by nut 43%; and snap ring 438. Cam 434 is preferably provided with a plurality of lobes 440 and flats 442 on its outer periphery and cooperates with a rigidly positioned but rotatably mounted follower 443 for imparting a reciprocating motion to the housing 410. Follower 443 is positioned on the lower portion of the casing 404 and comprises a non-friction bearing suitably mounted on a stub pin 444 which is rigidly secured to a side of casing 404 by a bolt 446 passing through an aperture formed in the casing and into the stub pin.

Intermediate the ends of shaft 416, within the cavity of casing 404, is a worm 448 fastened to shaft 416. Worm 448 meshes with a worm wheel 450 for driving the wheel from the external power source. Wheel 450 is suitably fixed intermediate the ends of a crusher roll spindle 452 as by a key for driving spindle 452, whereby the spindle is driven at a slow rate compared with shaft 416, in the normal manner of worm and wheel speed reduction. Spindle 452 is suitably journaled on the upper end of housing 410 by spaced, aligned bearings 454 and 456. The spindle is positioned in spaced parallel relation with pivot pin 412 and is adapted to support and drive crusher roll 402. Preferably, the rearward end of spindle 452 is provided with a spring retaining washer 458 while the other end extends through an enlarged bore 459 in casing 404 and outwardly of the casing for a limited distance. An integral annular flange 460 is formed on the spindle portion positioned in bore 459 and serves as an abutment for a spacer washer 462 fitted between housing 410 and the flange. Retaining washer 458, spacer washer 462 and flange 460 function to retain the crusher roll spindle within housing 410 and maintain worm wheel 450 in proper aligned relation with worm 448. On the extreme front end of spindle 452, outwardly of the casing, is the cylindrical crusher roll 402. The roll is secured against rotation on the spindle by a key or the like and locked in position by a washer and nut arrangement 464. *If desired, a dust protector may be provided around spindle 452 adjacent bore 459 for preventing the passage of foreign particles into the casing. This protector includes a cup-shaped dust seal 466 having an annular portion which is slipped over flange 460, bearing 462 and into bore 459. A metallic cup-shaped protective cap 468 is placed over the dust seal and suitably secured to casing 410. It will be noted that while the dust seal 468 has portions thereof disposed in the bore 459, sufiicient clearance is provided between seal 466 and the internal bore surfaces to permit relative movement between spindle 452 and casing 404 during reciprocation of spindle housing 410.

' To control the upward swing of spindle housing 410 caused by the cam-follower arrangement, a threaded adjustment screw 470 is positioned on an overhanging boss 472 formed on casing 404 (Figures 6 and 7). The inner end of screw 470 is operative to engage a stop 474 rigidly attached to an enlarged control abutment 476 integrally formed on the housing 410 adjacent cam 434. By adjustment of screw 470 in a vertical direction for varying the distance between the screw and stop, the upward swing of housing 410 and hence, the depth of penetration of crusher roll 402 may be controlled. A coil spring 478 carried on a guide pin 480 and inserted in an enlarged vertical bore 482 formed in control abutment 476 is provided for urging the crusher roll toward the grinding wheel, as inthe previous embodiments. The lower end of spring 478 seats against a raised portion 484 of casing base 408 while the upper end seats against a flat head portion 4860f pin 480. An adjustment screw 490 is posirapid rotation of shaft 416 by power source 432, cam

434 will be rotated upon rigidly positioned follower 440 to impart a reciprocating motion to the spindle housing. Meanwhile, worm 448 will drive spindle 452 slowly through wheel 450. As spindle 452 rotates, it drives crusher roll 402 fixedly carried thereon. This rotation combined with the reciprocating motion of spindle housing 410, forces crusher roll upwardly into repeated shock engagement with grinding wheel 400 to form a contour thereon and, due to the force exerted by spring 478, rotates grinding wheel 400. The working depth of the crusher roll in grinding wheel 400 is controlled by varying adjustment screw 470 which limits the upward movement of housing 410 about pivot pin 412 and thus limits the movement of crusher roll 402. a

it is to be noted that although the invention has been described with relation to the forming of a grinding wheel, it is equally applicable to dressing of the wheel. Dressing is defined as the reconditioning of a grinding wheel after the wheel has been operating for a period of time and the contours thereon have become dull through wear. Thus, in dressing the grinding wheel, the basic contour still remains on the grinding wheel but it has lost its fine edges for producing precision work. In applying the instant invention to the dressing of the wheel, the apparatus will operate in the same manner as in the forming of the grinding wheel by removing the necessary material from the wheel.

While several forms of the invention are illustrated and described, it will be apparent that variations in the design and construction of various elements of the forming apparatus may be made without departing from the spirit or the scope of the appended claims. In particular, it should be observed that while the crusher roll is driven from an external source and the grinding wheel is driven by the crusher roll in the preferred embodiments, this driving operation may be reversed with the grinding wheel being the power-driven member and the crusher roll rotated thereby. Moreover, other means may be used to reciprocate the crusher roll relative to the grinding wheel. As for example, a pulsating electromagnet may be used to intermittently attract the crusher roll spindle support for causing rapid impact engagements between the grinding wheel and the crusher roll. It is also contemplated that the gradual closing movement between the grinding wheel and the crusher wheel during-the forming operation may be effected by motion of the crusher roll towards the grinding wheel, rather than moving the grinding wheel towards the crusher roll.

Figure 8 illustrates schematically the alternative construction described above. In this figure grinding wheel 502 has a spindle 504 which is rotated by driving means indicated schematically by arrow 506. A crusher roll 508 is rotatably supported by a spindle 510 at one end of an arm 512. The other end of arm 512 is pivoted at 514 to a carriage-516. A pulsating electromagnet 518 has an armature 520 connected to an intermediate portion of arm 512, the pulsations of the electromagnet serving to force'crusher roll 503 toward grinding wheel 502. -A spring 522 between carriage 516 and arm 512 serves to constantly urge crusher roll 503 into engagement with grinding wheel 502. and to maintain this engagement betweenthe impacts caused by the pulsating electromagnet. With this arrangement, rotation of grinding wheel spindle 504 will cause continuous rotation of crusher roll 50-8 during the impacts and the intervening engagement intervals. "Means indicated schematically by double-ended arrow 524 may be provided for progressively moving the crusher roll toward the grinding wheel during the operation. This means may be in addition to the means shown schematically by arrow 526 for progressively moving the grinding wheel toward the crusher roll.

What is claimed is: v

1. In a mechanism employing a crusher roll for forming a contoured pattern on the grinding surface of a grinding wheel, a stationary casing having an enlarged cavity in the upper end and a bearing bore in the lower end, a housing pivotally mounted in the cavity of the casing and havinga spindle journaled therein, said spindle supporting said crusher roll in juxtaposed relation with a grinding wheel to be formed, a camshaft journaled in the bearing bore of the casing, means for slowly rotating said spindle and rapidly rotating said camshaft, saidlast-named means including a direct drive connected between a power input member and said camshaft and a speed-reduction mechanism interposed between said power input member and said spindle, and means for reciprocating said housing. comprising an irregularly formed member mounted on said rapidly rotated camshaft and a juxtaposed, concentric follower member mountedv on said spindle, whereby rotation of said camshaft operates to reciprocate the crusher roll into rapid periodic shock engagement with the grinding wheel;

2. In a. mechanism employing a crusher roll for forming. a contoured pattern on the grinding surface of a grinding wheel, a stationary casing having an enlarged cavity in its upper end and a bearing bore in its lower end, a housing pivotally mounted in the cavity and having a spindle journaled therein, said spindle supporting said crusher roll, means for biasing the crusher roll into light engagement with the grinding wheel, a camshaft journaled in said bearing bore, means for slowly rotating said spindle including a speed reduction mechanism interposed between the spindle and a power input member, means for directly driving said camshaft for rapid rotation, means for reciprocating said housing to reciprocate said spindle and crusher roll relative to the grinding wheel, said last named means including a multilobed cam secured to the camshaft and a follower member on said spindle in engaging relation with the cam, and adjustable means for limiting the reciprocating movement of said housing.

3. in a mechanism employing a crusher roll for forming a grinding wheel, a casing, a power input member, a housing pivotally mounted within said casing, a pair of coaxial members journaled within said housing including a tubular camshaft and a spindle, means for rotatably mounting said crusher roll on one endof said camshaft, means connecting said spindle to the crusher roll, means for slowly rotating said spindle including a speed reduction mechanism interposed between said power input member and the spindle, means directly connecting the camshaft to the power input member for rapidly rotating said camshaft, and means for rapidly reciprocating the spindle housing to bring the crusher roll into periodic shock engagement with the grinding wheel.

4. In a mechanism employing a crusher roll for forming a grinding wheel, a casing, a housing pivotally mounted within said casing, a pair of coaxial members joinnaled within said housing including a tubular camshaft and a spindle, means for rotatably mounting said crusher roll on said camshaft, means interposed between the easing and housing for biasing the crusher roll into light engagement with the grinding wheel, power input means directly connected to said camshaft for rapidly rotating the shaft, means for slowly rotating said spindle including planetary speed-reduction gearing interposed between the power input means and the spindle, said spindle being connected to the crusher roll for driving the roll, means for rapidly reciprocating the pivoted housing to bring the crusher roll into periodic shock engagement with the grinding wheel, said last named means including a multilobed cam member on the camshaft and a concentric follower rotatably mounted on the casing in engaging rotation with the cam member, and means for limiting the reciprocating movement of the housing.

5. in a mechanism employing a crusher roll for forming a grinding wheel, a casing, a housing pivotally mounted within said casing, 21 pair of coaxial members journalcd within said housing including a tubular camshaft and a spindle, said. crusher roll being rotatably mounted on the camshaft and connected to the spindle for rotation thereby, a first and a second power input means, said first power" input means being directly connected to said spindle for slowly driving the spindle, said' second power input means being directly connected to the camshaft for rapidly rotating the shaft, and means for rapidly reciprocating said housing about its pivotal axis, said last named means including an irregular member on the camshaft and a concentric follower rotatably mounted on the casing in engaging relation with the irregular member, whereby rotation of the camshaft is operative to reciprocate the crusher roll carried on the camshaft into periodic shock engagement with a juxtaposed grinding wheel.

6. In a mechanism employing a crusher roll for forming a grinding wheel, a stationary casing, a housing pivotally mounted within the casing and carrying a pair of coaxial shafts therein, said shafts including a camshaft ley means for directly driving said camshaft at a rapid rate, second pulley means for directly driving said spindle at a slow rate, means for reciprocating the pivoted housing including a multilobed cam on the camshaft and a concentric follower rotatably mounted on the casing in engaging relation with the cam, said reciprocating motion being imparted to said crusher roll whereby the crusher roll periodically imparts a shock force to a juxtaposed grinding wheel, and adjustable means for limiting the movement of the housing.

7. in a mechanism employing a crusher roll for forming a grinding wheel, a stationary casing, a housing pivotally mounted on said casing, a spindle rotatably journaled in said housing for supporting a crusher roll, said spindle having its axis positioned parallel to the pivotal axis of said housing, a camshaft rotatably journaled in said housing on an axis normal to said spindle axis, means for reciprocating said housing about its pivotal axis to bring said crusher roll into periodic shock engagement with a grinding wheel, said last named means including an irregular member secured to the camshaft and a follower member secured on the casing in engaging relation with the irregular member, driving means for rapidly rotating said camshaft, and means including a speedreduction mechanism between said driving means and said spindle for slowly rotating the spindle.

8. In a mechanism employing a crusher roll for forming a grinding wheel, a stationary casing, a housing pivotally mounted on said casing, a spindle rotatably journaled in said housing for supporting a crusher roll, said spindle having its axis positioned parallel to the pivotalaxis of said housing, a camshaft rotatably journaled in said housing, means for reciprocating said housing about its pivotal axis to bring said crusher roll into periodic shock engagement with a grinding wheel, said last named means including an irregular member secured to the camshaft and a follower member secured on the casing in engaging relation with the irregular member, driving means for rapidly rotating said camshaft, and means for slowly rotatingsaid spindle.

9. The combination according to claim 8, further provided with resilient means disposed between said casing and housing and urging said. crusher roll into light engagement with the grinding wheel.

10. in a mechanism employing a crusher roll for form ing a grinding wheel, a stationaray casing, a housing pivotally mountedon said casing, a spindle'rotatably journaled in said housing and supporting a crusher roll, said spindle having its axis positioned parallel to the pivotal ax s of said housing, a camshaft rotatably journaled in said-housing on an axis normal to said spindle axis, means for reciprocating said housing about its pivotal axis to brmg said crusher roll into periodic shock engagement with a grinding wheel, said last named means including 21 13 cam. secured to the camshaft and a follower fixedly mounted on the casing in engaging relation with the cam, means for rapidly rotating said camshaft, means including a worm and wheel for slowly rotating said spindle, adjustable means mounted in said casing and operative to engage said housing for limiting the movement of the housing, and resilient means interposed between the casing and housing, said resilient means urging said crusher roll into light engagement with the grinding Wheel.

11. The method of forming a profile inverse to that of a forming member on a grinding wheel having a crushable bond, comprising the steps of positioning a grinding wheel and a forming member adjacent each other, urging said forming member and grinding wheel into engagement, forcing said forming member and grinding wheel together in; arapid succession of small-amplitude impacts, maintaining said engagement between the forming member and grindin'gfwheel in the time intervals between said impacts,

, a forming member on a grinding wheel having a crushable bond, comprising the steps of positioning a grinding wheel and a forming member adjacent each other, urging said forming member and grinding wheel into engagcment, forcing said forming member and grinding wheel together in a rapid succession of small-amplitude impacts, maintaining said engagement between the forming memher and grinding wheel in the time intervals between said impacts, causing relatively slow movement of said forming member along the Working surface of said grinding wheel, said movement being continuous during said impacts and said intervening engagement, and progressively moving said forming member and grinding wheel toward each other.

13. The method of forming a profile inverse to that of a crusher roll on a grinding wheel having a crushable bond, comprising the steps of positioning a grinding wheel and a crusher roll adjacent each other, urging said grinding wheel and crusher rollinto mutual engagement, forcing said grinding wheel and crusher roll together in a rapid succession of small-amplitude impacts, maintaining said engagement in the time intervals between said impacts, and imparting slow rotation to one of said members so as to cause the other member to be continuously rotated thereby during said impacts and said intervening engagement intervals.

14. The method of forming a profile inverse to that of a crusher roll on a grinding wheel having a crushable bond, comprising the steps of positioning a grinding wheel and a crusher roll adjacent each other, urging said grinding wheel and crusher roll into mutual engagement, forcing said grinding wheel and crusher roll together in a rapid succession of small-amplitude impacts, maintaining said engagement in the time intervals between said impacts, and imparting slow rotation to said crusher roll so as to cause the grinding wheel to be continuously rotated thereby during said impacts and said intervening engagement intervals.

15. The method of forming a. profile inverse to that of a crusher roll on a grinding wheel having a crushable 16. The method of forming a profile inverse to that of a crusher roll on a grinding wheel having a crushable bond, comprising the steps :of positioning a grinding wheel and a crusher roll adjacent each other, urging said grinding wheel and crusher roll into mutual engagement, forcing said crusher roll toward said grinding wheel in a rapid succession of small-amplitude impacts, maintaining said engagement in the time intervals between said impacts, imparting slow rotation to said crusher roll so as to cause the grinding wheel to be continuously rotated thereby during said impacts and said intervening engagement intervals, and progressively moving said crusher roll and grinding wheel toward each other. 1

17. The method of forming a profile inverse to that of a crusher'roll on agrinding wheel having a crushable bond, comprising the steps of positioning a grinding wheel and a, crusher roll adjacent each other, urging said grinding wheel and crusher roll into mutual engagement, forcing said grinding wheel and crusher roll together in a rapid succession of small-amplitude impacts with the axes of the crusher roll and grinding wheel in a common plane, maintaining. said engagement in the time intervals between said impacts, and imparting slow rotation to said crusher roll so as to cause said grinding wheel to be continuously rotated thereby during said impacts and said intervening engagement intervals.

18. In combination, a spindle adapted to support a crusher roll, means for slowly rotating said spindle, a spindle housing rotatably supporting said spindle, means supporting said housing for reciprocatory movement transverse to the spindle axis, means continuously biasing said housing in one direction of reciprocation, and means independent of said biasing means for forcing said housing in said one direction in a rapid succession of smallamplitude movements.

19. A device as defined in claim 18, said housing supporting means comprising a pivot having an axis parallel to the crusher roll spindle axis.

20. In combination, a crusher roll having a profile for forming an inverse profile on a grinding wheel having a crushable bond, a casing, a housing mounted for recipnocatory movement within said casing, a crusher roll spindle in said housing, the axis of said spindle being transverse to said reciprocatory movement, means for rotating said spindle at a predetermined rate, a spring urging said housing in one direction of reciprocation, means for forcing said housing in said one direction in a rapid succession of small-amplitude impacts, said means including a cam member and a follower member mounted on said housing and said casing, and means for rotating said cam at a much faster rate than said spindle.

21. The combination according to claim 20, further provided with an adjustable stop for limiting the movement of said crusher roll in said one direction.

22. The combination according to claim 21, said cas ing supporting means comprising a pivot parallel to said spindle.

23. The combination according to claim 20, the rotating means for said cam and spindle comprising a shaft supporting said cam, a drive connection for said cam shaft, and speed reducing means between said cam shaft and said spindle.

24. In combination, a spindle adapted to support a crusher noll, means for slowly rotating said spindle, a spindle housing rotatably supporting said spindle, means supporting said housing for reciprocatory movement transverse to the spindle axis, said housing supporting means comprising a pivot having an axis lying in a plane normal to the crusher roll spindle axis, means biasing said housing in one direction of reciprocation, and means for forcing said housing in said one direction in a rapid succession of small-amplitude movements.

25. In combination, a spindle adapted to support a crusher roll, means for slowly rotating said spindle, a

1 5 spindle housing r'ota-tably supporting said spindle means supporting said housing for re'ciprocatory transverse to the? spindle axis, means biasing. said housing in: one direction of reciprocation, means for forcing said housing in said one direction in a rapid succession of small-amplitude movements, said last-named means comprising a cam member and a follower member, oneof said members being carried by said spindle housing, and means for rotating said cam member.

26. In combination, a crusher roll having a profile for forming an inverse of said'profileon a grinding Wheel having a crushable bond,- 21' spindle supporting said crusher roll, means for slowly rotating said spindle, a spindle housing rotatably supporting said spindle, means supporting said housing for reciprocatory movement transverse to the spindle axis,- means biasing said housing in one direction of reciprocation, andmeans for forcing s said housing in' said one direction in a rapid succession of small-amplitude movements.

References Cited in the file of this patent UNITED STATES PATENTS 151,449 Swan May 26, 1874 161,183 Venners Mar. 23, 1875 200,689 Brombacher Feb. 26, 1878 1,776,318 Keet Sept. 23, 1930' 2,156,584 Benedetti May 2, 1939 2,658,259 Aldino Nov. 10, 1953 FOREIGN PATENTS 11,990 Great Britain Apr. 28, 1865 340,164 Germany Sept. 3, 1921 401,615 Germany Sept. 8, 1924' 519,081 Great Britain Mar. 15, 1940 1,041,107

France May 27, 1953