US3075513A

US3075513A - Grinding wheel truing mechanism

Info

Publication number: US3075513A
Application number: US68070A
Authority: US
Inventors: William B Seidel
Original assignee: Cincinnati Milling Machine Co
Current assignee: Milacron Inc
Priority date: 1960-11-08
Filing date: 1960-11-08
Publication date: 1963-01-29
Anticipated expiration: 1980-01-29
Also published as: DE1427470A1; GB912297A

Description

W- B. SEIDEL GRINDING WHEEL TRUING MECHANISM Jan. 29, 1963 4 Sheets-Sheet 1 Filed Nov. 8, 1960 INVENTOR. WILLIAM B. SEIDEL fjvbwav" ATTORNEYS Jan. 29, 1963 w. B. SElDEL GRINDING WHEEL TRUING MECHANISM 4 Sheets-Sheet 2 Filed NOV. 8, 1960 W. B- SEIDEL GRINDING WHEEL TRUING MECHANISM Jan. 29, 1963 4 Sheets- Shegt :5

Filed NOV. 8, 1960 sol.

Jan. 29, 1963 w. a. SEIDEL GRINDING WHEEL TRUING MECHANISM Filed Nov. 8. 1960 4 Sheets-Sheet 4 A1], ISOL.

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SCR 4n Inca ZCR

SCR I ZCR || lCR .ACR

| ICR 3,075,513 GRINDING WHEEL TRUllNG MEQHANISM Wiiiiam B. Seidel, Cincinnati, Ohio, assiguor to The Qincinnati Miliing Machine Co., Cincinnafi, Ohio, a corporation of Shin Filed Nov. 8, 19:30, Ser. No. 68,070 Claims- (Cl. 125-11) This invention relates to a grinding wheel truing mechanism adapted for use in a precision grinding machine.

in the manufacture of angular contact annular ball bearings, it is necessary to grind a workpiece profile which includes both an arcuate portion and an adjacent straight portion. it is a common practice not to make the straight portion exactly tangent to the arcuate portion, but rather to leave a slight corner condition between the two surfaces which will hold the balls in the arcuate ball track. The arcuate portion must be ground to a depth slightly greater than that to which the straight profile portion is ground. Each of the two surfaces is generally ground in a separate operation, the arcuate track being ground first and the straight portion being ground in a subsequent operation. It is a better practice to grind both the arcuate ball track and the fiat land in one operation.

In grinding both profile surfaces in one operation, an

ccurate grinding wheel profile must be generated and maintained. This requires an accurate truing mechanism which will create a peripheral contour, the parts of which will not change relative to one another in succeeding truing operations. With a wheel profile having a slight corner between straight and arcuate portions thereof, cam guidance at the corner is diificult. Moreover, the use of a cam restricts the flexibility of use of the machine since a different cam is required for each contour.

It is therefore an object of this invention to provide a truing mechanism whereby an arcuate portion and adjacent straight portion may be trued on a grinding wheel periphery by a single truing tool in a single truing operation without cam guidance.

It is a further object to provide a mechanism whereby an arcuate profile portion and an intersecting adjacent straight profile portion may be trued on the periphery of a grinding wheel.

It is another object of this invention to provide a truing mechanism whereby the path of the truing tool may be altered to true a variety of grinding wheel profiles having straight and arcuate profile portions.

Still another object is to provide a mechanism for truing a straight profile portion and an arcuate profile portion in one continuous movement of the truing tool which is simply and inexpensively constructed yet which is accurate through repeated operations.

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.

A truing mechanism constructed in accordance with the preferred form of this invention utilizes a single point truing tool mounted in a truing slide member. The truing slide member is received for reciprocal movement in a truing yoke which is pivotal relative to the grinding wheel. A rotary driving member develops a torque which is divided by the mechanism to produce movement of the truing slide in the yoke and pivotal movement of the yoke, the yoke remaining stationary while the slide is moved therein. The relative movements of the slide and yoke are adjustable to produce movement of the truing tool through a path by which an arcuate profile portion inter- 3,fi75,5l3 Patented Jan. 29, M963 sected by a straight profile portion may be trued as well as a profile in which the straight portion is tangent to the arcuate portion. The mechanism is accurate and the same profile may be repeatedly trued.

The construction and operation of the truing mechanism are described in the following detailed description with reference to the attached drawings wherein;

FIG. 1 is an elevational view of the truing mechanism.

FIG. 2 is a sectional View of FIG. 1 on line 2-2.

FIG. 3 is a sectional view of FIG. 2 on line 3-3.

FIG. 4 is a sectional view showing the details of the drive input mechanism.

FIG. 5 is a sectional View of FIG. 4 on line 5-5.

FIG. 6 is a schematically represented hydraulic circuit to operate the truing attachment.

FIG. 7 is an electrical control circuit for operation of the hydraulic circuit of FIG. 6.

FIG. 8 is a sectional view of FIG. 3 on line 88.

FIG. 9 is a partial section of a grinding wheel showing the profile of the grinding periphery.

As shown in FIG. 1, the truing mechanism is located behind the grinding wheel it which is rotatably supported in a grinding machine Wheelhead 11. The truing mechanism is supported by a truing carriage 12 which is received by a slide housing 14 that is fixed in the wheelhead l1 and forms a part thereof. The grinding wheel 19 rotates about an axis which is fixed relative to the slide housing 14 of the wheelhcad. The truing carriage 12 is movable toward and away from the grinding wheel It by selected rotation of a compensation screw 16 which is axially fixed relative to the slide housing 14 and threadedly engaged with the truing carriage. The compensation screw 16 is utilized to move the truing carriage 12 relative to the slide housing 14 toward the grinding wheel 19 to maintian the truing mechanism in a position to perform a truing operation as the grinding wheel it! is reduced in diameter through use.

Fixed on the end of the truing carriage l2 and forming a part thereof is a bracket is in which a yoke 2a is pivotally received. The yoke 20 is held in the bracket 13 by

pins

22, 24 fixed therein and extending from the yoke into the bracket where they are in pivotal contact with

balls

26, 28 respectively. The

balls

26, 28 are held in place in the bracket 18 by pin seats 3-9, 32 respectively, fixed in the bracket. Also contained in the bracket it; above the yoke 29 is a gear mechanism 34- by which a truing tool 42 is moved during a truing operation. The mechanism 34 is actuated by a pair of pistons $6, 38 (FIG. 6) which are received in a cylinder block it; that is fixed on the rear of the bracket 13.

The single point truing tool 42 is carried in the yoke 23 for truing the grinding wheel it? when moved across the peripheral cutting surface thereof. As shown in FIGS. 2 and 3, the truing tool 42 is received in a truing slide member 44 which is received in the yoke it) on antitriction balls is. The anti-friction balls it are received in ball tracks 48, St} in the yoke 2t} and held in spaced relationship to one another by

cage members

52, 54. The truing tool 42 is adjustable toward and away from the grinding wheel It} by rotation of a screw as which is received through a sleeve 53 that extends through a slot 659 at the rear of the yoke Ed. The truing tool 42 is held in a fixed angular position in the truing slide 44 since it has a longitudinal slot 62 (see FIG. 8) on one side engaged by a key pin 64 fixed in the truing slide. When the truing tool 42 is axially positioned to true a particular radius, with the point of truing tool 42 a predetermined distance from the axis defined by the center of pivot balls 26, 2d, a locking screw 66 is tightened down to rigidly fix the tool in the truing slide 44.

By moving the truing slide 44 in the yoke 2t? while holding the yoke stationary, a straight profile portion may be sweets is trued on the grinding wheel it). By stopping the movement of the truing slide 44 in the yoke 29 and then by swinging the yoke, the point of the truing tool 42 will move in an arcuate path for truing an arcuate profile portion on the peripheral surface of the grinding wheel The gear mechanism 34 is shown in detail in PEG. 4. Limited rotary motion is introduced to the actuating mechanism 34 from the pair or" reciprocating pistons 36, 355 in the cylinder block 4% (FIG. 6). Connected to each of the pistons as, 33 is a drive chain 6%. The chain 68 is pinned at its center to to a rotatable sleeve '72. "the sleeve 72 is received in annular bearings 74, 6 which are received in a retainer member '77 fixed in the bracket 33. The sleeve is rotatable around the pin 22, ball 25, and pin seat so as the chain ss is moved. On the lower end of the sleeve '72 is a gear 78 Which is fixed for rotation tl1erewith by a key 8%. A nut 82 holds the gear 78 on the sleeve '72. In mesh with the gear 78 is a sector gear which is fixed to the upper end of a shaft 85 which extends into the yoke 29, as shown in FIG. 1, where it is journalcd for rotation. As shown in FIG, 3, a pinion gear 88 is fixed on the lower end of the shaft as. The pinion 38 is engaged with a rack gt} which is machined on the rear of the truing slide 44.

By the described mechanism, reciprocal motion of the pistons 36, 38 (FIG. 6), to which the chain n3 is attached at each end, is converted into rotary motion at the sleeve '72 (HQ. 4). The rotary motion of the sleeve 72 produces a torque which is transmitted from the gear 78 through the sector gear so to the shaft 86. The shaft 36, pinion $8, and rack 98* converts the torque into motion of the truing slide. To allow the truing slide 44 to be moved by the pinion 88, the yoke 23 must offer more resistance to movement than the slide 5 or otherwise the yoke would tend to be swung by the movement of the gear 72. An annular drag seal 2 is received in the bracket 18 and engaged with an annular surface 94 on the top of the yoke The drag seal 92 in addition to keeping grinding dirt out of the gear mechanism, creates a resistance to movement of the yoke which, in combination with antifriction balls as, renders the truing slide 44 more freely movable than the yoke. Consequently rotary motion of the shaft 86 in the yoke 2i) will occur and the truing slide 44 will move transversely in the yoke.

if the movement of the truing slide in the yoke 26 is stopped before the rotary input of sleeve 72 is exhausted, the remaining torque produced at the sector gear 84 may be utilized to swing the yoke in the bracket 18. Therefore a pair of stop members 98, 161) (FIG. 2) are received in one side of the yoke 24} and a third stop member M2 (PEG. 8) is received in the same side of the yoke but extends through the truing slide 44 to the opposite side where it is adapted to engage the bottom of a counterbored portion 194 thereof. (As shown in FIG. 2, stop 19?; extends from the side of the yoke Ztv and is covered by a guard member 96 which is normally received over the adjusting knob 162a of the stop during machine operation.) The stop S (FIG. 2) is a fixed stop and limits the extreme movement of the slide 44 at the right side of the yoke 29. The stop 1% is an adustable stop which may be used in place of the fixed stop 98 to restrict the extreme movement of the slide 44'; to the right in the yoke 26) but to a selected point to the left of the fixed stop 93. As shown in FIG. 2 the truing slide 44 is in its extreme right position. The left side stop 102 (FIG. 8) is adustable relative to the yoke 2b in which it is threadedly received. Assuming that the stop 16-2 is at its extreme left adjustment, the dimension 1% represents the allowable movement of the truing slide 44 in the yoke or the length of the strai ht path which the truing tool 42 may trace. 7 7

By the construction described, assume that the sleeve 72 (FIG. 4) may be rotated through a reciprocal rotary movement of 180 degrees by operation of the pistons 36, 33 (FIG. 6). Of this motion, 90 degrees in' one direcltion is necessary to move the truing slide 44 (FIG. 2) from engagement with the fixed stop 98 through a dis tance 1% to engagement with the left stop 162. When the stop 102 is engaged by the truing slide 44 and the sleeve 72 (FIG. 4) continues to rotate in the same direction, the balance of the rotary movement, degrees, is transferred to the yoke 29 to swing it thrOugh an arcu ate path. The engagement of the stop Hi2 by the truing slide 44 fixes the truing slide in the yoke 2 and the force created by the continued rotary movement of the sleeve '72 in the same direction is transmitted through the stop 182 to the yoke 2d. The force produced thereby tending to swing the yoke 2% is greater than the resistance to movement of the yoke created by the drag seal 92. The yoke 2b then becomes more freely movable than the truing slide 44- during cOntinued rotation of the sleeve 72 through the second 90 degrees.

By the combination of the movement of the truiug slide 44 in the yoke 2t) and the subsequent pivotal movement of the yoke, the truing tool is carried along a path havinga straight portion and an arcuate portion. The point of the vtruing tool 52 then may be utilized to true a grinding Wheel l0 having a profile contour which includes a straight portion and an arcuate portion. If the stop 102 (FIG. 8) is positioned such that the point of the truing tool 42 is swung about a radius which is equal to the perpendicular distance from the center of the radius to the straight portion of the path traced by the point, the straight portion of the path would be tangent to the arcuate portion of the path. The mechanism may thcnbe used to true such a profile on the periphery of the grinding wheel ill. The point of tangency and the center C of the arcuate portion define a centerline of pivot CL, FIG. 9, used as a reference line for altering the relationship of the straight and arc-uate portions of the path traced by the truing tool 42.

If the stop 192 (MG. 8) is adjusted to terminate th movement of the truing slide 44 in the yoke 29 at a place where the point of the truing tool 42 (FIG. 3) is swung about a radius which is greater than the perpendicular distance from the center of the radius to the straight poi tion of the path, the straight portion of the path traced by the truing tool would intersect the arcuate portion of the path, that is, the straight portion would not be tangent to the arcuate portion. One form of this condition is shown in FIG. 9. The grinding wheel 15} has a straight profile portion res and an arcuate profile portion 110. The available straight movement of the truing tool is represented by dimension 112 and is equal to th dimension 106 in FIG. 8. If all available straight movement were used, the resulting form would be a straight portion tangent to an arcuate portion. The stop 102, however, is adjusted to the right (FIG. 8) to shorten the path of the truing slide by an amount equal to dimension 114 to offset the start of the arcuate path from the center line of pivot CL. When the straight movement of the truing slide 42 is stopped, the swing of the yoke 26 begins. The point of the truing tool 42 now traces an arcuate path the radius R of which is greater than the perpendicular distance 116 from the center C of the arcuate portion to the straight portion of the path. Thus a stepped relation is created on the grinding wheel periphery, the step being represented by the dimension S, and the straight portion 108 intersects the arouate portion 110. The offset dimension 114 may be expressed relative to the radius R and step S by the formula;

' ofiset= /R (RS) Therefore, by calibrating the knob 162a (FIG. 8) on the stop 102, the truing mechanism'may be conveniently adjusted to true a range of stepped forms on the grinding wheel.

In the specific embodiment described herein, the total straight movement is assumed to be suchthat at full 'rnoven'ient of the'truingslided i, a straight'suri'ace tangent to an arcuate surface is trued. By extending the beyond the dimension lilo (H6. 8), a straight surface which would intersect the arcuate surface but which would produce no step. In such a case the offset would be in the opposite direction from the centerline of pivot CL from the ofiset 114 shown in FIG. 9.

In truing the wheel form in FIG. 9, the truing tool 42 would move from position 118 through a straight path and succeeding arcuate path and stop at position 129. The truing tool must then be returned to its starting position 118. This is done by reversing the action of the pistons 36, 38 (FIG. 6). The sleeve 72 (FIG. 4) is then rotated through 180 degrees in the opposite direction. Initially, the truing slide 44 moves more freely since the shaft 86 is rotated in a direction tending to move the truing slide from engagement with stop 162 (FIG. 8) toward stop 93 (H6. 2) and the drag seal ;92 (FIG. 4) opposes movement of the yoke in the opposite direction. Therefore the truing slide 44 moves first in the yoke 29 and then the yoke finally swings to its starting position. In such a motion, the truing tool 42 would be moved away from the grinding wheel ll} (FIG. 9) and returned to its starting position file without contacting the grinding wheel. Truing contact then occurs only when the truing tool 42 moves from the start position 118 to the stop position 12%.

To insure that the mechanism tunes the same contour each time and that the spaced relationship of the aircuate portion and the straight portion of the periphery remains constant, the return swing of the yoke 20 to the starting position must end at the distance from the line CL each time. Therefore, a stop pin 122 (FIGS. 4, 5) is fixed in a cap 124 which is adjustable relative to the top of the bracket 18 and may be locked thereto by a draw-down bolt 126. The stop pin 122 extends through an arcuate clearance slot 128 in the bracket 18. The lower end of the stop pin 122 is adapted to engage a stop 130 fixed in an angle bracket 132 which is secur d to the top of the yoke 29 and moves therewith. As shown in FIG. 5, the stop 13% is engaged with the stop pin 122 at the starting position 118. In a truing operation, the yoke 29 would move counterclockwise (as viewed in FIG. 5) and the stop 13o would move away from the stop pin 122 during the truing of the arcuate portion of the grinding wheel periphery. Upon the return swing of the yoke 20, the stop 13a would move back toward the stop pin 122 for engagement therewith. The use of the rigid stop 122 to terminate the return swing of the yoke 2% then places the yoke in the same starting position relative to line CL each time.

Rigid stops

98, 100, 1ii2 (FIGS. 2, 8) in the yoke 20 control the movement of the truing slide 44 and the result is repeated movement of the truing tool through an identical ath.

P An electrical control circuit is shown in FIG. 7 for operation of the truing hydraulic circuit shown in FIG. 6. In the starting condition, the piston as is in its forward position as shown and piston 33 is in the retracted position. Therefore, limit switch lLS is operated and limit switch 2L8 is in t o released condition at the start of a truing cycle. (The trip point of both limit switches lLS and 2L8 may be adjusted in machine set up for a particular job.) With limit switch llLS operated relay SCR is energized. Switch SW1 is momentarily closed to start the truing cycle. During the moment that switch SW1 is closed, relay lCR is energized through that switch and immediately relay 2CR is energized through contacts of relays 1CR and SCR. Relay 20R latches around the contacts of relay SCR. Immediately, relay ECR is energized through the contacts of relays lCR, 2CR and CR (normally closed). Solenoid ISOL is then energized through contacts of relay 30R.

When soleonid 1501. is energized the plunger of the reversing valve 134 shifts to the right from the position slide movement the mechanism would true shown in PEG. 6. The main fluid pressure line 136 is connected to the fluid line 138 which is connected in the cylinder block as to the left side of piston 36. Line 14a is connected through the valve 134 to return line 142. Piston 36 is forced to the right and the other piston 38 moves to the left as the chain 68 is moved. The sleeve 72 is rotated counterclockwise, and the truing tool movement begins. At this time limit switch 11.3 is released and relay 50R is deenergized. Switch SW1 may now be released since the latch circuit through contacts of relays lCR and 56R (normally closed) will hold relay lCR energized.

After the pistons 35, 38 have completed their stroke, limit switch ZLS is operated by piston as have completed their stroke, limit switch 2L8 is operated by piston 36 and as a result, relay 60R is energized. When relay CR is energized relay 3C3 is dropped to deenergize solenoid lSOL. Relay 42CR is energized at this time through contacts of relays 5C3. (normally closed), lCR, and dCR. Relay 40R latches around contacts of relay 6C3. Solenoid 2501. is now energized through contacts of relay 4-CR and the plunger of valve 134 shifts to the left. Pressure line 1136 is connected to fluid line 140, and return line 142 is connected to iluid line 138. The movement of the

pistons

36, 38 is reversed to return the truing tool' 4-2 to its starting position. Limit switch 21.8 is released immediately as the reverse movement begins, dropping relay GCR, and the limit switch 1L3 is operated when the return is completed. Relay SCR is energized when limit switch lLS is operated. Relays 1CR and 40R are dropped when relay ECR is energized. When relay 10K is deenergized, relay 208. is also cleenergized, and when relay 4GB. i deenergized, solenoid ZSOL is deenergized.

The truing cycle is then completed, the truing tool having moved from its starting position to its finished position and then returned to the starting position. The length of the straight portion of the path of the truing tool 42 relative to the arcuate portion is determined by the length of movement of the slide 4 in the yoke 2d allowed by the setting of the stops 1%, N2 relative to one another and to the fined stop 93 and the amount of rotary movement of thes leeve '72 produced by the

pistons

36, 38. The relationship of the straight portion to the arcuate portion is determined by the adjustment of the stop 1 92 relative to the centerline of pivot CL (FIG. 9).

if the stops il -319, 1G2 (FIGS 2, 3) are adjusted to hold the truing slide 44 in a fixed position in the yoke, the entire rotary movement of the sleeve '72 (FIG. 4) would be transmitted to the yoke 29 which would rotate with the sleeve 72. The stop 122 (FIG. 5) would then be adjusted counterclockwise to allow a predetermined amount of arcuate movement of the yoke beyond the point shown. The full 180 degrees of movement of the sleeve 72 can be transmitted to move the yoke through a 180 degree swing for truing an arcuate profile across the entire grinding wheel width 1&9 FIG. 9). The stop 122 would then be moved in the slot 128 to the end opposite that in which the stop is shown to allow for the full swing. As shown, the stop 122 is in a position which would allow for a swing of the yoke 26 of approximately degrees with full movement of the truing slide 44 through the distance 1%. The range of swing in the mechanism described can therefore be adjusted to any value between 90 and degrees. It a radius of less than 180 degrees is desired on the profile with no straight portion, the stop 122 may be set in the appropriate position to provide an accurate starting position. The trip plungers of limit switches 1LS and 21.5 (FIG. 6) would have to be adjusted to operate the control relays at the proper time since the

pistons

36, 38 would not complete full travel in the cylinder block as.

lt is understood that the specific arcuate movements scream referred to herein are for purposes of illustration only and are not intended to limit the scope of this invention.

What is claimed is:

1. In a grinding machine having a grinding Wheel with a contoured profile thereon, a truing mechanism comprising in combination, a pivotally movable member mounted adjacent the grinding wheel, a slidably movable member received in said pivotally movable memher for transverse movement therein, a truing tool recoived in said slidably movable member and extending therefrom toward said riiiding wheel, means initially to render one of said movable members more freely movable than the other of said movable members, means to render the other of said movable members more freely movable than said one movable member after a predetermined movement of said one movable member, a drive member operatively connected to both of said movable members, one at a time in one direction in accordance with relative freedom of movement therebe tween for truing a straight portion and an arcuate portion on the profile or" said grinding wheel, and means to reversely move said drive member whereby said movable members move in the reverse direction one at a time to return said truing tool to a starting position.

2. in a grinding machine having a grinding wheel with a contoured profile thereon, a truing mechanism comprising in combination, a bracket mounted adjacent the grinding wheel, a pivotally movable member mounted on said bracket, a slidably movable member received in said pivotal member for transverse movement therein, means to render said slida'ole member more freely movable than said pivotal member, a truing tool received in said slidable member and extending therefrom toward said grinding wheel, a rotatable drive shaft journaled in the pivotal member and connected to said slidable member for movement thereof when rotated, a drive member connected to said drive shaft, means to rotate said drive member a predetermined amount initially to transmit rotation to said drive shaft in the pivotal member and move said slidable member therein, and means to stop movement of said slidable member in said pivotal memher before said drive member has rotated said predetermined amount and to connect said drive shaft to said pivotal member for pivotal movement thereof, said truing tool thereby moved for truing a straight portion and an arcuate portion on the profile of said grinding wheel.

3. In a grinding machine having a grinding wheel with a contoured profile thereon, a truing mechanism comprising in combination, a bracket mounted adjacent the grinding wheel, a pivotally movable member mounted on said bracket, a slidably movable member received in said pivotal member for transverse movement therein, a truing tool received in said slidable member and extending therefrom toward said grinding wheel, means to render said slidable member more freely movable than said pivotal member, a rotatable drive shaft journaled in the pivotal member and connected to said slidable memher for movement thereof when rotated, a drive member journaled in the bracket and connected to said drive shaft, means to rotate said drive member a fixed amount in one direction initially to transmit rotation to said drive shaft in the pivotal member and move said slidable member therein, means to step movement of said slidable member in one direction in said pivotal member before said drive member has rotated said fixed amount and to connect said drive shaft to said pivotal member for pivotal movement thereof in one direction a predetermined amount, said truing tool thereby moved for truing a straight portion and an arcuate portion on the profile of said grinding wheel, means to efiect rotation of said drive member said fixed amount in the other direction, and means to stop movement of said slidable member in the other direction in said pivotal member before said drive member has rotated said fixed amount and to connect said drive shaft to said pivotal member for pivotal movement thereof in the other direction a pred termined amount, said truing tool thereby returned to a starting position.

4. In a grinding machine having a grinding wheel with a contoured profile thereon, a truing mechanism comprising in combination, a bracket mounted adjacent the grinding wheel, a pivotally movable member received in said bracket on an axis, a slidably movable member received in said pivotally movable member for transverse movement therein, a truing tool received in said slidably movable member and extending therefrom toward said grinding wheel, means to render said slidably movable member more freely movable than said pivotally movable member, a rotatable drive shaft journaled in the pivotally movable member and spaced from said axis, said shaft connected to said slidably movable memher for movement thereof when rotated, a drive member journaled in said bracket for rotation on said axis and connected to said drive shaft for rotation thereof, means to rotate said drive member a fixed amount one way and the other way, a pair of adjustable stop members received in said pivotally movable member for engaging said slidably movable member to stop movement thereof before said drive member rotates said fixed amount and to connect said drive shaft to said pivotally movable member for movement thereof, the adjustment of said stop members determining the relative amount of movemerit of said movable members eifected by said fixed rotation of the drive member and the direction of said fixed rotation determining the direction of movement of said movable members, and means to advance said pivotally movable member toward said grinding wheel 5. in a grinding machine having a grinding wheel with a grinding profile including an arcuate portion and a straight portion, a truing mechanism comprising in combination, a truing carriage received adjacent said grinding wheel, a yoke pivotally received in said carriage, a pair of transversely spaced stops in said yoke, a truing slide received in said yoke for movement between said stops, a truing tool fixed in said truing slide and extending therefrom toward said grinding wheel, a drive shaft journaled in said yoke and connected to said truing slide, said drive shaft operable, when a torque is applied thereto, to move said truing slide from one of said stops to the other of said stops and thereafter to pivot said yoke for movement of said truing tool to true said straight and arcuate portions, and means to apply a torque to said drive shaft.

6. In a grinding machine having a grinding Wheel with a grinding profile including an arcuate portion and a straight portion, a truing mechanism comprising in combination, a truing carriage mounted adjacent said grinding wheel, a yoke pivotally received in said carriage on an aXis, a pair of transversely spaced stops in said yoke, 21 truing slide received in said yoke for movement between said pair of stops, a truing tool fixed in said truing slide and extending therefrom toward said grinding wheel, a rotatable drive shaft journaled in said yoke and spaced from the pivot axis thereof, said drive shaft connected to said truing slide for movement thereof from one stop to the other stop of said pair of stops and thereafter for pivotal movement of said yoke when a torque is applied to said drive shaft, and a drive mechanism operable to produce a torque and including a drive member journaled in said carriage and rotatable about the pivot axis of said yoke, said mechanism connected to said drive shaft for transmission of said torque thereto to effect movement of said truing slide and said yoke for truing said straight and arcuate profile portions.

7. in a grinding machine having a grinding wheel with a grinding profile including a straight portion and an arcuate portion, a truing mechanism comprising in combination, a truing carriage received adjacent said grinding wheel, a yoke pivotally received in said carriage, a pair of transversely spaced stops in said yoke, a truing slide received in said yoke for movement between said steps, a truing tool fixed in said truing slide and extending therefrom toward the grinding wheel, a rack fixed to said truing slide, a rotatable drive shaft journaled in said yoke, said shaft having a pinion fixed thereto and engaged with said rack, a drag member received in said carriage and engaged with said yoke, said drag member effective to impede movement of said yoke and to render said truing slide more freely movable than said yoke, means to apply a torque to said shaft to effect movement of said truing slide from one of said stops to the other of said stops and thereafter to pivot said yoke a predetermined amount in one direction, said truing tool thereby tracing a path for truing said straight portion and said arcuate portion, and means to reverse said torque to effect movement of said truing slide from the other of said stops to the one of said stops and thereafter to pivot said yoke said predetermined amount in the other direction.

8. In a grinding machine having a wheelhead and a grinding wheel rotatably received therein, said grinding wheel having a grinding profile including a straight portion and an arcuate portion, a truing mechanism comprising in combination, a truing carriage received in said wheelhead, a pivotally movable yoke received in said carriage on an axis, a positive stop in said carriage adapted to engage said yoke, a pair of transversely spaced stops in said yoke, a truing slide received in said yoke for movement between said pair of stops, at truing tool fixed in said trning slide and extending therefrom toward said grinding wheel, a rack fixed to said truing slide, a rotatable drive shaft journaled in said yoke, said drive shaft parallel to the pivotal axis of said yoke and spaced therefrom, a pinion fixed to said drive shaft and engaged with said rack, a drag member received in said bracket and engaged with said yoke to render said truing slide more freely movable than said yoke, means to apply a torque to said drive shaft to effect movement of said truing slide from one stop to the other stop of said pair of stops and thereafter to pivot said yoke a predetermined amount away from said positive stop, said truing tool thereby tracing a path for truing said straight portion and said arcuate portion, means to reverse said torque applied to said drive shaft to effect movement of said truing slide from the other stop to the one stop of said pair of stops and thereafter to pivot said yoke to engage said positive stop, and means to adjust the other stop of said pair of stops relative to the one stop of said pair of stops to change the path traced by said truing tool for altering the relation of said straight portion to said arcuate portion.

9. In a grinding machine having a wheelhead and a grinding wheel rotatably received therein, said grinding wheel having a grinding profile including a straight portion and an arcuate portion, a truing mechanism comprising in combination, a truing carriage received in said wheelhead for movement toward said grinding wheel, said carriage having a bracket extending therefrom, a pivotally movable yoke received in said bracket on a pivot axis, an adjustable positive stop received in said bracket and adapted to engage said yoke, a pair of adjustable transversely spaced stops in said yoke, a truing slide received in said yoke for movement between said pair of stops, a truing tool fixed in said truing slide and extending therefrom toward said grinding wheel, a rack fixed to said truing slide, a rotatable drive shaft journaled in said yoke, said drive shaft spaced from and parallel to the pivot axis of said yoke, a pinion fixed to said drive shaft and engaged with said rack, a drag member received in said bracket and engaged with said yoke, said drag member effective to render said truing slide more freely movable than said yoke, means to apply a torque to said drive shaft in one direction to move said truing slide from one stop to the other stop of said pair of stops and thereafter to pivot said yoke away from said positive stop a predetermined amount for movement of said truing tool in said straight and arcuate paths to true said straight and arcuate portions of said grinding wheel profile, the relative adjustment of said pair of stops determining the relative length and relationship of said straight and arcuate paths and the positive stop determining the starting position from which said truing tool is moved, means to reverse said torque to rotate said drive shaft in the other direction and move said truing slide from the other stop to the one stop of said pair of stops and thereafter to pivot said yoke to engage said positive stop, and means to advance said carriage toward said grinding wheel for positioning said truing tool relative to the periphery of said grinding wheel.

10. In a grinding machine having a wheelhead and a grinding wheel rotatably received therein, said grinding wheel having a grinding profile including a straight portion and an arcuate portion, a truing mechanism comprising in combination, a truing carriage received in said wheelhead for movement toward said grinding wheel, said carriage having a bracket extending therefrom, a pivotally movable yoke received in said bracket on an axis, a positive stop received in said bracket and adapted to engage said yoke, a pair of transversely spaced stops in said yoke, a truing slide received in said yoke for movement between said pair of stops, a drag seal received in said bracket and engaged with said yoke, said seal effective to render said truing slide more freely movable than said yoke, a truing tool fixed in said truing slide and extending therefrom toward said grinding wheel, a rack fixed to said truing slide, a rotatable drive shaft journaled in said yoke and extending therefrom, said drive shaft parallel to and spaced from the pivot axis of said yoke, a gear fixed to said drive shaft outside said yoke, a pinion fixed to said drive shaft in said yoke and engaged with said rack, a drive member journaled in the bracket on the pivot axis of said yoke, said drive member having a drive gear fixed thereon and engaged with said gear, means to apply a torque to said drive member in one direction to effect movement of said truing slide from one stop to the other stop of said pair of stops and thereafter to effect pivotal movement of said yoke a predetermined distance away from said positive stop for truing said straight and arcuate portions of said grinding wheel profile, means to reverse said torque to effect movement of said truing slide from the other stop to the one stop of said pair of stops and thereafter to pivot said yoke to engage said positive stop, means to adjust the other stop relative to the one stop of said pair of stops for altering the relationship of said straight and arcuate paths, and means to advance said carriage toward said grinding wheel.

2,294,492 Wilson Sept. 1, 1942

Claims

5. IN A GRINDING MACHINE HAVING A GRINDING WHEEL WITH A GRINDING PROFILE INCLUDING AN ARCUATE PORTION AND A STRAIGHT PORTION, A TRUING MECHANISM COMPRISING IN COMBINATION, A TRUING CARRIAGE RECEIVED ADJACENT SAID GRINDING WHEEL, A YOKE PIVOTALLY RECEIVED IN SAID CARRIAGE, A PAIR OF TRANSVERSELY SPACED STOPS IN SAID YOKE, A TRUING SLIDE RECEIVED IN SAID YOKE FOR MOVEMENT BETWEEN SAID STOPS, A TRUING TOOL FIXED IN SAID TRUING SLIDE AND EXTENDING THEREFROM TOWARD SAID GRINDING WHEEL, A DRIVE SHAFT JOURNALED IN SAID YOKE AND CONNECTED TO SAID TRUING SLIDE, SAID DRIVE SHAFT OPERABLE, WHEN A TORQUE IS APPLIED THERETO, TO MOVE SAID TRUING SLIDE FROM ONE OF SAID STOPS TO THE OTHER OF SAID STOPS AND THEREAFTER TO PIVOT SAID YOKE FOR MOVEMENT OF SAID TRUING TOOL TO TRUE SAID STRAIGHT AND ARCUATE PORTIONS, AND MEANS TO APPLY A TORQUE TO SAID DRIVE SHAFT.