US2930373A

US2930373A - Grinding machine truing mechanism

Info

Publication number: US2930373A
Application number: US795710A
Authority: US
Inventors: Wilbur F Jessup; Robert H Weisgerber
Original assignee: Cincinnati Milling Machine Co
Current assignee: Milacron Inc
Priority date: 1959-02-26
Filing date: 1959-02-26
Publication date: 1960-03-29
Anticipated expiration: 1977-03-29

Description

March 29, 1960 w. F. JESSUP ETA GRINDING MACHINE mums MECHANISM 6 Sheets-Sheet 3 Filed Feb. 26, 1959 INVENTOR. WILBUR F. JESSUP ROBERT H.WE|SGERBER BY ATTORNEYS March 1960 w. F. JESSUP ETAIL 2,930,373

GRINDING MACHINE TRUING MECHANISM Filed Feb. 26, 1959 e Sheets-Sheet. 4

INVENTOR. WILBUR F. JESSUP ROBERT H. WEISGERBER ATTORNEYS March 29, 1960 w. F. JESSUP ETAL 2,930,373

GRINDING MACHINE TRUING MECHANISM 6 Sheets-Sheet 5 Filed Feb. 26, 1959 ATTORNEYS March 29, 1960 w. F. JESSUP ET AL 2,930,373 GRINDING MACHINE TRUING MECHANISM Filed Feb. 26, 1959 6 Sheets-Sheet 6 X INVENTOR.

WILBUR F'. JESSUP ROBERT H. WEISGERBER ATTORNEYS United States Patent GRINDING MACHINE TRUING MECHANISM Wilbur F. .lessup and Robert H. Weisgerber, Cincinnati, Ohio, assignors to The Cincinnati Milling Machine Co., Cincinnati, Ohio, a corporation of Ohio Application February 26, 1959, Serial No. 795,710

9 Claims. (Cl. 125-11) The present invention relates to a truing mechanism for a grinding machine and more particularly to a mechanism for forming an arcuate profile on the grinding or regulating wheel of the machine.

Forming an arcuate profile on a wheel by swinging a cutting element about 'a fixed center presents difficulties. If different curved profiles are required means must be provided to locate the fixed center at various positions without interference with the wheel or other elements of the machine. Moreover, if a particuarly shallow curved surface is required on the wheel the radius of the cutting element may be too large to locate the fixed center on the machine. The forming of an arcuate surface on the wheel by traversing the cutting element across the wheel and imparting contouring movement to the cutting element by a single cam also presents difficulties. The cam, which must be curved in conformity with the curve desired on the surface of the wheel, is expensive to produce and can only be used for a single arcuate conformation.

In the present invention an improved truing mechanism is provided by which arcuate surfaces can be formed on wheels without the need of a fixed center for the cutting element or the need of a specially shaped cam. In brief, in the preferred embodiment of the present invention, conventional means is provided to pass the cutting element transversely across the wheel. Contouring movement towards and away from the wheel is imparted to the cutting element by providing a pivotal follower bar connected at its center to the member carrying the cutting element, the ends of the follower bar engaging fixed cam surfaces. These cam surfaces, which may be simply straight bars, straddle the plane of the wheel and are each inclined with respect to the traversing path in opposite directions. Thus as the member carrying the cutting element is moved transversely relative to the wheel, the ends of the follower bar are guided by the oppositely sloping cam surfaces and the center of the bar describes an arcuate path, which will be an ellipse if the guides have straight cam surfaces. This motion of the center of the follower bar is transmitted to the cutting element through the member carrying said element and an arcuate conformation corresponding thereto will be formed on the wheel.

If, from the plane of the wheel, the cam surfaces slope away from the wheel as they extend outwardly from said plane, a convex peripheral surface will be formed on the wheel. If the cam surfaces slope away from the wheel as they extend inwardly toward said plane, a concave peripheral surface will be formed on the wheel. The cam surfaces can be easily angularly adjusted to provide concave and convex arcuate surfaces on the wheel of different radii of curvature.

It is therefore an object of the present invention to control the movement of the cutting element.

, It is another object of the present invention to provide ice 4 2 a truing mechanism which is simply and quickly adjustable to form surfaces of different radii of curvature on the wheel of a grinding machine.

It is yet another object of the present invention to provide a mechanism capable of forming either a concave or convex periphery on a grinding or regulating wheel of a machine tool.

It is still another object of the present invention to provide a grinding wheel truing mechanism which is guided to form arcuate surfaces on a wheel of the machine by two straight camming surfaces.

It is a further object of the present invention to provide a simple, effective, and easily adjustable truing mechanism operable to form various arcuate surfaces on the wheels of a grinding machine.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof, and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

In the drawings:

Fig. 2 is a view through the line 22 of Fig. 1; Fig. 3 is a view through the line 3--3 of Fig. 8;

Fig. 4 is a view, partly in cross-section, of the grinding;

wheel truing mechanism as viewed in Fig. 1;

Fig. 5 is a view through line 5-5 of Fig. 1; Fig. 6 is a view through line 66 of Fig. 4;

Fig. 7 is a view through line 77 of Fig. 11;

Fig. 8 is a cross-sectional view of the regulating wheel truing mechanism through line 8-8 of Fig. 10;

Fig. 9 is a fragmentary elevational view of the regulating wheel truing mechanism as viewed in Fig. 1;

Fig. 10 is a view through line 1010 of Fig. 1;

Fig. 11 is a view through line 11-11 of Fig. 4;

Figs. 12 and 13 are schematic diagrams showing the contours formed on the grinding wheel and regulating wheel, respectively, by the respective truing mechanisms; and

Fig. 14 is a schematic diagram showing another embodiment of the present invention.

In Fig. 1 there is shown a centerless grinding machine having a base 15, a control cabinet 16 connected to the base, and a grinding wheel 17 rotatably mounted in a housing 18 on the base. The grinding wheel truing mechanism, shown generally at 19, is mounted on the base behind the housing 18 and extends through the housing to engage the grinding wheel. A slide 20, having a workpiece support 21 at one end, is movably mounted on the base 15 and supports a regulating wheel slide 22. The slide 22 has a housing 23 in which is rotatably mounted a regulating wheel 24, opposite the grinding wheel 17, to engage a workpiece 25 supported by the workpiece support 21 and hold the same in engagement with the grinding wheel. The regulating wheel truing mechanism, shown generally at 26, is mounted on the housing 23. r

The grinding wheel 17 which rotates in plane A,'and regulating wheel 24 which rotates in plane B have arcuate peripheral workpiece engaging surfaces 17a and 24a, surface 17a being concave and surface 24a being truing device 26 includes a support 30 (see Fig. 8), mounted on housing 23 for swiveling relativethereto; and having an upstanding wall 30a on the side facing" the grinding wheel 17, which may be considered a front wall. The top of the housing 23 has a circular recess 31 through which passes a slot 32 extending transversely relative to the .regulating wheel 24. The base 30b of support 30 has a circular portion 33 through which slot 34 passes, the circular portion 33 being received in recess 31. The base 30b also hasan upstanding rear portion 302. The base 30b has slots 35 (see Fig. with shoulders 35a spaced from the pivot mounting defined by portion 33 and recess 31 to receive the heads of bolts 36, which are threadedly received in housing 23 to clamp the base 30b thereto in an angularly adjusted position. The support 30 has

side plates

30c and 30d secured to the base 30b.

As shown in Figs. 8 and 10, a slide 40 is slidably received in ways 41 in front wall 30a and threadedly receives lead screw 42 journaled in

side plates

30c and 30d. The slide 40 is reciprocated transversely relative to regulating wheel 24 by reversible hydraulic motor 43 (see Fig. 10) mounted on side plate 30d and operatively connected to lead screw 42. An elongated member, indicated generally at 39, is slidably received in slide 40 and is axially movable toward and away from the wheel. The member 39 has a sleeve 44 which carries a bar 45, at one end of which is mounted a diamond cutting element 46. At its upper end the sleeve 44 has a cap 47 secured thereto on which is mounted an annular ring 48 (see Fig. 8) in which screw 49 is rotatably carried by two antifriction bearings 50 mounted in ring 48 and sandwiched between flange 51 and nut 52 on screw 49. Within the sleeve 44 the screw 49 is threadedly engaged with collar 53, secured to the top of the diamond holder bar 45, and extends into a central bore 54 in bar 45 where it threadedly engages backlash nut 55 threadedly received in bore 54 for adjustment relative to collar 53. Outside the sleeve 44 and above cap 47 the hub 56 of lever 57 is connected to the screw for adjustment of the holder bar 45 relative to the sleeve 44. Key 58 prevents rotation of cap 47 relative to sleeve 44, and key 59, rotatably carried by a plunger 60 threadedly received in cap 47, prevents rotation of the holder bar 45 relative to sleeve 44 and cap 47.

The sleeve 44 moves axially in 'slide 40 between straight tracks 65 and 66 (see Fig. 3) secured in the slide and extending parallel to the sleeve 44. The sleeve rolls on balls 67 held in ball retainers 63 and sandwiched between the sleeve 44 and the

tracks

65 and 66, the balls engaging with grooved races 69 in the tracks and sleeve. The sleeve 44 has a lug 70 connected to its outer surface to which is connected a pair of rods 71 extending parallel to the sleeve and having springs 72 thereon. The slide 40 has a top plate 73 (see Fig. 8) having an opening 74 through which the sleeve extends. The rods 71 abut against the top plate 73 when the sleeve is .in its upper position, relative to the slide, and the springs, which are sandwiched between the lug 70 and top plate 73 and under compression, urge the sleeve downward relative to the slide. The sleeve may be manually raised to its upper position to disengage the cutting element 46 from the wheel 24 by lever 75 (see Fig. 10) pivotally connected to cap 47 of sleeve 44 at 76. The lever 75 has a leg 77 with roller 78 thereon, which is swung by operation of the lever to engage the top 73 of the slide and urge the sleeve upward. V

The cap 47 has behind the sleeve 44 a depending clevis 85, by means of which the member 39 is pivotally connected, at 84 to the midpoint of a follower bar 86. At one end bar 86 has a shoe 88 pivotally connected theretoadjacent its forward face by bolt 87, and at its opposite end has a similar shoe 90 pivotally connected thereto adjacent its rear face by bolt 89 (see Fig. 10).

A bracket 91 is connected to the upstanding rear portion 302 of base 30b of the support 30 by bolts 92 and is adjustable laterally relative thereto by set screws 93 threadedly received in bracket 91, and engaged with lugs 94 connected to portion 30s and extending through slots 95 in bracket 91. Connected to the forward and rear faces, respectively, of bracket 91 by bolts 96 and pins 97 are spaced

square plates

99 and 100 having circular openings 101 therein.

Discs

102 and 103 are rotatably received, respectively, in openings 101 and are each connected to guides which may be in the form of bars, disc 102 being connected to guide bar 104 and disc 103 being connected to guide bar 105 by screws 106 and pins 107.

A plate 112 is connected to bracket 91 by bolts 113 and is adjustable relative thereto by set screws 114 threadedly received in bracket 91 and engaged with pins 115 extending from plate 112 through slots 116 in bracket 91. Plate 112 lies between the planes of guide bars 104 and 105 and these guide bars are adjustably connected thereto, guide bar 104 being adjustably connected to the front face of plate 112 by bolts 117 extending through slots 117a in plate 112, and guide bar 105 being adjustably connected to the rear face of plate 112 by bolts 118 extending through slots 118a in plate 112 so that the guide bars can be pivoted about the points at which they are rotatably connected to the support by

discs

102 and 103 received in

plates

99 and 100. Gages 119 are mounted on brackets 122 (see Fig. 9) carried on rods 120 which are received in lugs 121 connected, respectively, to

side plates

30c and 30d of support 30. Sensitive adjustment of the guide bars relative to plate 112 is accomplished by means of set screws 123 thread edly received in plate 112 and engaged with pins 124 mounted in the guide bars and extending into slots 125 in plate 112.

Guide bars 104 and 105 each have a straight upper cam surface 104a and 105a, respectively, to engage the shoes, cam surface 104a engaging shoe 38, and cam surface 105a engaging shoe 90 to impart contouring movement to the sleeve 44 as the slide is reciprocated transversely relative to the regulating wheel. The shoes are urged against the guide surfaces by the action of springs 72 which urge member 39 toward the wheel.

The grinding wheel truing device 19 is shown in Figs. 4, 6 and 11. A swivel support plate is pivotally connected by pin 131 to base 15 (see Fig. 4). The swivel plate 130, which defines a support for a slide 132, has ways 131' extending transversely to the grinding wheel 17 to slidably receive the slide. Lead screw 133 is operatively connected to reversible hydraulic motor 134 (see Fig. 6) and engages nut 135 fixed in the slide 132 to reciprocate the slide on the ways. An elongated member, designated generally at 129, is slidably received in the slide 132 and includes a sleeve 136 mounted for axial movement towards and away from the grinding wheel by means which may include tracks and balls similar to the structure shown in Fig, 4 for the regulating wheel truing device. A lever 137 (see Fig. 1) permits manual rotation of an eccentric pin 138 engaged with sleeve 136 to manually retract the sleeve relative to the wheel. The member 129 includes a bar 139 (see Fig. 4) slidably received in the sleeve and held against rotation relative thereto by key 140. The bar 139 has a diamond cutting element 141 at one end for engagement with the grinding wheel and is adjustable axially relative to the sleeve by crank 142. The crank 142 rotates lead screw 143 journaled at one end in collar 144 which is connected to bar 139. The screw threadedly engages at the opposite end with bracket 145 connected to the end of sleeve 136. The bracket 145 has a slot 146 dividing the bracket into two portions where screw 143 is threadedly received, screws 147 (see Fig. 11) being provided to adjustably space said portions to eliminate backlash in screw 143.

The bracket 145 has below the sleeve 136 a clevis 151 by means of which the member 129 is pivotally connected, at 150, to the midpoint of a follower bar 152. At one end the follower bar has a shoe 153 pivotally connected thereto above the .uppersurface of the bar and at the opposite end has shoe 154 pivotally connected thereto below the bottom surface thereof (see Figs; 6 and 11).

'Bracket 155 is connected to the lower surface and edge .of the swivel support plate 130 by bolts 156. The bracket has an upper platform 157 on one side of the plane A of the grinding wheel and a lower platform 158 on the other side thereof. The

platforms

157 and 158 have connected to their upper surfaces, by

bolts

159 and 160, guides 161 and 162, respectively, which may, for example, be bars or plates. The bolts 159 define a pivot point for each guide bar, and bolts 160 are received in slots 163 in the guide bars, so the guide bars may be adjustably pivoted about the bolts 159. The guide bars 161 and 162 have

straight cam surfaces

161a and 162a which engage, respectively, the

shoes

153 and 154. The guide bars have pins 164 extending therefrom and extending into recesses 165 in

platforms

157 and 158 of bracket 155, the pins being engaged by set screws 166 threadedly received in the platforms for sensitive adjustment of the guide bars relative to the bracket. Indexed plates 167 are located on the upper surfaces of

bracket platforms

157 and 158 to gage the. location of the guide bars.

Bracket 145 has

ears

145a and 145b extending on either side thereof (see Fig. 11) which receive rod 170 which is slidably received in slide 132. The rod has nuts 169 on one end to engage the ears on the side thereof opposite the slide and a nut 171 at the end within the slide, A spring 172 is received on the rod within the slide between the nut 171 and a plate 173 connected to the rear of the slide. Thus, the spring, which is under compression, urges the bracket 145, and hence the sleeve 136, toward the wheel, thereby urging the shoes against the guide bars. A rod 174 secured in the plate 173 engages an adjustable bolt 175 threadedly received in

ears

145a and 145b and defines a stop to limit the forward movement of the sleeve toward the wheel. A clamp 176 received in plate 173 looks the rod 170 at selected positions.

The operation of the truing mechanisms will be best understood by reference to Figs. 1'2 and 13. The support 130 associated with the grinding wheel 17 has ways extending transversely to the wheel, and the support may be positioned with the ways normal to the plane A of the wheel. The slide 132 is reciprocated on the ways by motor 134 for traversing movement relative to the wheel as indicated by arrow C in Fig. 12. The member 129, which is carried in the slide, will therefore move in translation across the wheel but contouring movement, that is, movement towards and away from the wheel, will be imparted thereto, and to the cutting element 141 carried thereby, by the follower bar 152 pivotally connected to member 129 at 150. The movement of the follower bar 152, the ends of which are engaged with

cam surfaces

161a and 162a of the guides, is determined by the

guides

161 and 162 which straddle the plane of the wheel and are inclined equally in opposite directions relative to the ways, and which slope away from the wheel as they extend toward the plane A of the wheel, as shown in Fig. 12. The pivot point 150, which is at the midpoint of bar 152, describes an elliptical are E as the slide, and member 129, is traversed across the wheel. The are E described by the point 150, which will be the same as the are F described by cutting element 141 and the concave profile cut in the wheel, may be expressed mathematically with reference to an x axis extending parallel to the ways through the point where the cam surfaces of the guides intersect, and a y axis through the point 0,

2 r L FEE /2 =1 4 4 tan 04 2 Where a is the angle between the guide surfaces, as shown in Fig. 12, and L is the length of the follower barbetween the guide surfaces. The radius of curvature'of are E at x--0 is:

L a p= tan 01/2 The support 30 associated with the regulating wheel 24 (see Fig. 13) has ways 41 extending transversely to the wheel which may be positioned normal to the plane B of the wheel so that the slide 40, when reciprocated by motor 43, will have a traversing movement as indicated by arrow D. The guides and 104 straddle the plane of the wheel and are inclined at equal but opposite angles to the ways, as the guides associated with the grinding wheel, but slope away from the wheel as they extend outwardly from the plane B of the wheel as shown in Fig. 13. The midpoint of the follower bar 86 which is engaged with guide cam surfaces 104a and 105a and pivotally connected at 84 to member 39, will describe an elliptical arc G as the slide 40 and member 39 are moved in translation across the wheel. However, the profile imparted to wheel 24 by the cutting element 46 which describes an arc H similar to arc G, will be convex and, if bar 86 is equal in length to bar 129 and a, which is the angle between the guide surfaces 104a and 105a, is equal to a, will bear a mating relation to the profile imparted to the grinding wheel 17.

The present invention has been shown and described in conjunction with a centerless grinder, and it will be evident that the invention is suitable for the truing of wheels used in through feed grinding where the wheels are held a fixed distance apart and the workpiece passed therebetween, or for the truing of wheels used in infeed grinding, where a workpiece is placed between the wheels which converge to form the workpiece. Similarly, the invention can be used in association with a grinding wheel for form grinding on a center type machine or in conjunction with any machine for forming an arcuate surface, or profile, on a wheel.

The arcuate profile formed on the grinding or regulating wheel will be symmetrical about the central plane of the wheel A or-B if, as shown in Figs. 12 and 13: the ways are normal to the plane of the wheel; the guides associated with a particular wheel are inclined at equal but opposite angles to the ways; the member (129, 39) is pivotally connected to the midpoint of the follower bar; and the cutting element is at the central plane of the wheel when the pivot point (150, 84) is at the line which bisects the angle a or a between the guide cam surfaces.

It may, however, be desirable to form an unsymmetrical profile on the wheel to facilitate through feeding of the workpieces or to form unsymmetrical workpieces by infeed grinding or form grinding. This may be done either by: swiveling the supports so that the ways are not normal to the plane of the wheel; inclining the guides on each side of the member at unequal angles relative to the ways;

displacing the pivot point from the midpoint on the follower bar; or by displacing the cutting element so that it will not bisect the periphery of the wheel when the pivot point bisects the angle a or at between the guides. Thus it will be evident that a wide variety of arcuate profiles can be formed on either the regulating wheel or grinding Wheel by the mechanism of the present invention.

It will be noted that with the use of one continuous straight cam surface oneach guide, as shown in Figs. 12 and 13, a continuous elliptical arcuate conformation is imparted to the

wheel

17 or 24 across the entire periphery of the wheel. Other profiles will be formed with different shaped guide bars. For example, as shown in Fig. 14, the guide surfaces can each have two straight cam surfaces 261a-261b; and 262a--262b, respectively, with the surfaces on each of the guides inclined relative to each other. The follower bar 252 is of a length to engage simultaneously the two inner cam surfaces 261a and 262a during a portion of the traversing movement of. the member 229 carrying the cutting element, and.

smears to engagesimultaneously the inner earn surface of one guide bar and the outer cam surface of the other guide bar during another portion of the traversing movement. With this construction different curves will be imparted to difierent segments across the periphery of the wheel. When the ends of the follower bar 252 are engaged, respectively, with the inner cam surfaces 261a and 262a, one curve will be imparted to segment 21711 of the periphery of the grinding wheel 217. When one end of the follower bar 252 is engaged with outer surface 262k and the other end thereof engaged with inner cam surface 261a a different curve will be formed on segment 21711 of the periphery of the grinding wheel. Similarly, yet another curve will be imparted to segment 2170 when the follower bar is engaged simultaneously 'with outer cam surface 261b and inner cam surface 262:: during another portion of the traversing movement.

What is claimed is:

l. A truing mechanism for a grinding machine having a rotatable wheel mounted thereon comprising a support, a member mounted on the support for traversing movement relative to the wheel and having a cutting element at one end to engage the wheel, said member being movable towards and away from the wheel for contouring of the wheel as said member is traversed, a follower bar pivotally connected to the member, and guides mounted on the support to engage the follower bar on both sides of the member and thereby control the contouring movement of the member relative to the wheel as the member is moved transversely thereto.

2. A truing mechanism for a grinding machine having a rotatable wheel mounted thereon comprising a support, a slide mounted on the support for traversing movement relative to the wheel, a member slidably received in the slide and having a cutting element atone end to engage the wheel as the slide is moved transversely thereto, a follower bar pivotally connected to the member, and guides on the support to engage the follower bar on both sides of the member.

3. A truing mechanism for a grinding machine having mounted thereon a rotatable wheel with a workpiece engaging periphery comprising a support having ways extending transversely to the wheel, a slide mounted on the ways, an elongated member slidably received in the slide for axial movement relative thereto and having 'a cutting element at one end to engage the periphery of the wheel, means to reciprocate the slide on the ways, a follower bar pivotally connected to the elongated member, and two guides mounted on the support and oppositely inclined relative to the ways to engage the follower bar on both sides of the elongated member and thereby control the axial movement of the elongated member as the slide is moved transversely relative to the wheel.

4. A truing mechanism for a grinding machine having mounted thereon a rotatable wheel with a workpiece engaging periphery comprising a support having ways extending transversely to the wheel, a slide mounted on the ways, an elongated member slidably received in the slide for axial movement relative thereto and having a cutting element at one end to engage the periphery of the wheel, means to reciprocate the slide on the ways, a follower bar pivotally connected to the elongated memher, two guides mounted on the support having straight cam surfaces oppositely inclined relative to the ways, a shoe pivotally mounted to the follower bar on each side of the elongated member for engagement with the cam surfaces, and means to urge the shoes against the cam surfaces as the slide is moved transversely relative to the wheel. I

5. A truing mechanism for a grinding machine having mounted thereon a wheel rotatable in a-plane with a workpiece engaging periphery comprising a'supporthaving ways extending transversely to the plane of the wheel and normal thereto, a slide mounted on the Ways, an

elongatedmember slidably received in the slide for axial movement relative thereto and having a cutting element atone end to engage the periphery of the wheel, means to reciprocate the slide on the ways, a follower bar pivotally connected to the elongated member, two guides mounted on the support having cam surfaces adjustably inclinable at equal but opposite angles relative to the ways, a shoe pivotally mounted to the follower baron each side of the elongated member and atequal distances therefrom for engagement with the cam surfaces, and means to urge the shoes against the cam surfaces to guide the cutting element of the elongated member in contouring movement as the slide is moved transversely relative to the wheel.

6. A grinding machine truing mechanism for forming a convex surface on the periphery of a wheel mounted on the machine and rotating in a plane comprising 'a support, a member mounted on the support for traversing movement relative to the wheel and having a cutting element at one end to engage the periphery of the wheel, said member being movable towards and away from the wheel for contouring of the wheel as said member is traversed, a pair of guides mounted on the support straddling the plane of the wheel and sloping away from the wheel as they extend outwardly from said plane, and a follower bar pivotally connected to the member and engaging said guides on each side of said member to control the contouring movement of the cutting element relative to the wheel as the member is moved transversely thereto.

7. A grinding machine truing mechanism for forming a concave surface on the periphery of a wheel mounted on the machine and rotating in a plane comprising a support, a member mounted on the support for traversing movement relative to'the wheel and having a cutting element at one end to engage the periphery of the wheel, said member being movable towards and away from the wheel for contouring of the wheel as said member is traversed, a pair of guides mounted on the support straddling the plane of the wheel and sloping away from the wheel as they extend inwardly toward said plane, and a follower bar pivotally connected to the member and engaging said guides on each side of said member to control the contouring movement of the cutting element relative to the wheel as the member is moved transversely thereto.

8. A truing mechanism for a grinding machine having a grinding wheel rotatable in a plane and a regulating wheel rotatable in a plane, the wheels being positioned and contoured to form arcuate profiles on workpieces placed therebetween, the mechanism comprising a support associated with each wheel, a slide mounted on each support for traversing movement relative to the wheel associated therewith, a member slidably received in each slide and having a cutting element at one end to engage the wheel as the slide is moved transversely thereto, guides on each support straddling the plane of the wheel associated therewith, the guides on one support sloping away from the wheel associated therewith as they extend outwardly from said plane and the guides on the other support sloping away from the wheel associated therewith as they extend inwardly toward said plane, and a follower bar pivotally connected to each member and engaging the respective guides on each side of the member to control the contouring movement of the cutting element relative to the wheels as the respective members are-moved transverselythereto.

9. A truing mechanism for a grinding machine having mounted thereon a rotatable wheel with a workpiece engaging periphery comprising a support having ways extending transversely to the-wheel, a slide mounted on the ways, an elongated member slidably received in the slide for axial movement relative thereto and having a cutting element at one end to engage the periphery of the wheel, means to reciprocate the slide-on the ways, a follower bar pivotally connected to the elongated member, two guides mounted on the support to engage the follower bar on both sides of the elongated member, at least one of said guides having two straight cam surfaces inclined relative to each other whereby the axial movement of the elongated member is controlled as the slide is moved transversely relative to the wheel to impart one curve to one segment of the periphery of the wheel when one end of the follower bar is engaged with one of the cam surfaces on said one guide and to impart another curve to a different segment of the periphery of the wheel when said one end of the follower bar is engaged with the other cam surface on said one guide.

References Cited in the file of this patent UNITED STATES PATENTS 1,825,753 Nenninger Oct. 6, 1931