US2175057A - Spindle reciprocating mechanism for grinding machines - Google Patents

Description

Oct. 3, 1939. B. A. KEARNS SPINDLE RECIPROCATING MEGHANISM FOR GRINDING MACHINES Filed March 28, 1938 5 Sheets-Sheet l B. A. KEARNS Oct. 3, 1939.

SPINDLE RECIPROCATING MECHANISM FOR GRINDING MACHINES 5 sheets-sneu 2 Filed March 28, 1938 MJHNI m Oct. 3, 1939. l B. A. KEARNs SPINDLE RECIPROCATING MECHANISM FOR GRINDING MACHINES 5 Sheets-Sheet 5 Filed March 28, 1938 ATTORNEY.

B( A. KEARNs oct. 3, 1939.

SPINDLE RECIPROCATING MECHANISM FOR GRINDING MACHINES Filed March 28 1938 5 Sheets-Sheet 4 ATTORNEY.

Och 3y i939., B, A, KEARNS A 2,175,157

SPINDLE RECIPROCATING MECHANISM FOR GRINDING MACHINES Filed March 28, 1958 5 sheets-sheet 5 jeg ATTORNEY.

Cil

Patented Oct. 3, 1939 UNITED lerares SPINDLE RECIPROCATING MECHANISM FOR GRINDING MACHINES Bernard A. Kearns, Cincinnati, Ohio, assigrxor to Cincinnati Grinders Incorporated,

Cincinnati,

Ohio, a corporation of Ohio Application March 28, 1938, Serial No. 198,440

1.3 Claims.

This invention relates to grinding machines and more particularly to an improved spindle reciprocating mechanism therefor.

One of the objects of this invention .is to provide a new and improved mechanism for axially feeding the spindle of a grinding wheel, either manually or automatically.

Another object of this invention is to provide a mechanism of the character described which Imay be conveniently operated manually by the operator to effect continuous reciprocation, or automatically actuated to perform a single stroke.

A further object of this invention is to provide a mechanism which is especially suitable for finish grinding a square shoulder on a Work piece at the same time that the diameter is finished.

An additional object of this invention is to provide a mechanism which is especially useful for shoulder grinding work and which is adjustable so that compensation may be made for wheel wear.

Other objects and advantages oi the present invention should be readily apparent by reference to the following specification considered in conjunction with the accompanying drawings' illustrative of one embodiment thereof, but it will be understood that any modifications may be made in the specc structural details within the scope of the appended claims without departing from or exceeding the spirit of the invention.

Referring to the drawings in which like reference numerals indicate like or similar part's:

F.' gure 1 isa side elevation of a grinding Wheel head unit showing the application of this invention thereto.

Figure 2 is a detail section on the line 2 2 of Figure 1 showing the spindle actuating piston.

Figure 3 is a detail section on the line -t of Figure 2.

Figure 4 is a vertical section through the grinding wheel spindle as viewed on the line il-4 of Figure 1.l

Figure 5 is an enlarged detail of a ratchet stop mechanism.

Figure 6 is an enlarged vertical section through the actuating mechanism for the spindle as viewed on the line 6-6 of Figure 4.

Figure 7 is a detail sec-tion on the lirici-'H of Figure 6.

Figure 8 is a section on the line 8 8 of Figure 6.

Fgure 9 is a detail section on the line S- of Figure 5.

Figure 10 is a detail section on the' line lil-I0 of Figure 6.

Figure 11 is a detail section on the line Il-II of Figure 6.

Figure 12 is a detail section on the line 12-12 of Figure 8.

Figure 13 is a diagrammatic view showing the relationship between a grinding wheel and a Work piece.

Figure 14 is an lil-iii of Figure 6.

One of the items which adds to the cost of manufacturing multiple diameter work pieces is the operation of finishing the internal corners formed by two intersecting surfaces. A common example of this is the internal corner formed by a shoulder at one end of a cylindrical surface. If the cylindrical surface is to serve as a bearing member, and the shoulder asa lateral guide, it will be apparent that a part mounted on the cylindrical surface must have unhindered utilization of that surface in order that the shoulder may serve -as a guide. It is therefore essential that no superfluous material be left in the corners by the manufacturing processes. Heretofore, an extra machining operation was usually necessary in order to remove this material.

This invention is directed to a mechanism for so manipulating the grinding wheel that it will not only simultaneously finish grind the two intersecting surfaces but will also produce a square corner between the two surfaces in such a manner that subsequent finishing operations are unnecessary.

Briefly, this is accomplished by supporting a grinding wheel indicated by the reference numeral ii! in the diagrammatic sketch, Figure 13, for oscillation about an axis li which is arranged at a slight angle with respect to the axis of rotation i2 of the work piece I3. If the axis of rotation li is arranged below the laxis of rotation Il! of the grinding wheel, as shown in Figure 1,

enlarged section on the line it vwill be apparent that as the grinding wheel support l5 moves about the axis il, that the grinding Wheel il) will move toward and from the work piece I3. On account of the angular relationship of the axes i l and I2, the grinding wheel will not move toward the workalong a path perpendicular to the axis indicated by the reference numeral I6 in Figure 13 whichis perpendicular to the axis ll and therefore slightly. inclined with respect to the axis I 2. This means that the grinding wheel can be trued to provide a first grinding surface l1, and a second grinding surface I8, having an included angle of intersection I9 which is equal l2 but along a path y to the angle of intersection 28 of the cylindrical surface 2i of the work and the face l22.

In addition, the grinding wheel is provided with a movement parallel to its axis of rotation and in a direction indicated by the arrow 23V in Figure 13. If the movement along the path I8 and the one along the path 23 are executed simultaneously there will be a resultant movement along the path 24. It will be noted that if the grinding wheel can follow the path -24 in moving toward the work piece, that the corner 25 of the grinding wheel will move directly toward the internal corner 26 of the work piece, and in so doing will simultaneously grind both the cylindrical surface 2| and the face 22. The mechanism for reciprocating the grinding wheel either manually or automatically, whereby this and kindred results may be obtained, will now be described, the manual control mechanism being described iirst.

In Figure 1 of the drawings, the reference numeral 21 indicates generally a grinding wheel support unit, which may be mounted on a fixed support, such as 28, with the axis of the grinding wheel parallel to the axis of the work, a8 when grinding cylindrical surfaces having shoulders at each end; or inclined to the axis of the work as suggested in connection with Figure 13.

The grinding wheel I8 is supported on the end of a spindle 28, Figure 4, which is antifrictionally journaled at spaced points 38 and 3l in the housing l5. The end of the spindle opposite to the grinding wheel is provided with a driving pulley 32 which, as shown in Figure 1, may be connected by a plurality of belts 33 to a driving pulley 34 secured to the end of the armature shaft of the motor 35. Thus the spindle is adapted to be power rotated by means self-contained in the housing l5 and movable therewith.

The spindle 29 has an intermediate collar 88, which is antifrictionally connected to a ring 81, the ring being pivotally connected at diametrically opposite points to a lever 38 which is pivotally supported at 39 in the housing I5 and operatively connected at the outer end 48 to a reciprocating mechanism. It should now be apparent that as the end 48 of the lever 38 is moved in the plane of Figure 4, that the grinding wheel spindle will be axially moved.

The mechanism for reciprocating the spindle is more particularly shown in Figure 6, and is entirely contained in a housing 4l which is adapted to be mounted and secured over the top of an opening 42 in the support I5, and automatically operatively interconnected with the end 48 of the lever 38 upon assembly.

There is a vertical sleeve 43 which is antifrictionally supported at 44 and 45 in the housing 4l. The end of this sleeve, as shown in Figure 4, is provided with a guideway 46 in which slides a pin carrying slide 41., A pin 48 carried by this slide ts in a block 48, as shown in Figure 11, the block fitting in across slot 58 formed in a plunger 5I. This plunger is surrounded by a sleeve 52 which has a portion cut away to formshoulders 53, and means are provided whereby the plunger 5l is continuously urged in the direction of arrow 54, and the sleeve 52 is continuously urged in the direction of arrow 55 whereby any lost motion between the plunger 5I and the sleeve 52 is climi nated.

The end 40 of lever 38 ts between the end of plunger 5I, and the end of a second plunger 56 which is urged in one direction by a spring 51 interposed between the end of the plunger and a plug 58 fixed in the end of the sleeve 52. It

is this spring which continuously urges the parts shown in Figure 11 in opposite directions. It will beapparent that if` the pin 48 is located eccent'rlcally to the axis of rotation of the sleeve 43, that when the sleeve is rotated the pin will cause movement of lever 38 by means of the mechanical connections j ust described.

No positive stops are providedfor limiting the,

movement of the spindle, the length of movement being controlled by oscillating the pin 48, 90 to "each side of a center position. Therefore the axis of eccentricity of the pin is made to normally lie in a plane perpendicular to the axis of rotation of the spindle in order to determine the center position. The movement of the spindle in each direction from this center position will then depend upon the length of the effective radius of eccentricity. Therefore, means are provided for centralizing the pin, and thereby the spindle in this center position. This aids in work set-up.because a work piece having an annular groove and opposing shoulders to be ground, may be positioned with the center of an annular groove in the plane of this center position.

By adjusting the eccentricity of the pin to make the radius equal to one-half oi the desired width of the groovethe grinding wheel may be moved into the center of the groove and then oscillated to grind the shoulders.

This centralizing mechanism comprises an elongated sleeve 58, Figures 6 and 14, upon the periphery of which are cut rack teeth 68 which inter-mesh with gear teeth 6| cut in the periphery of the sleeve 43. The sleeve 59 has cap members 62 mounted in each end and interconnected by a spring 63 which passes through the center of the sleeve. The cap members' are sufllciently large in diameter to overlap the sleeve and lengage a part of the housing 4l. The sleeve is made of the proper length so-that when both cap members are in engagement with the housing there is The fixed housing 4I has an upstanding bracket 81 attached to one side, as by screws .88, and the upper end of this bracket has an elongated tubular portion 68 which forms a vertical bearing fora crank housing 10. This crank housing 'carries two pins 1l and 12 which, as shown in Figure 8, depend into engagement with opposite sides of the roller 86 whereby upon rotation of the crank, the roller 88 is picked up and moved to rotate the sleeve (i3. The upper end of the housing 18 has a boss 13, as shown in Figure 7, through which is formed a bore 14 for receiving an operating lever 15. The boss 13 is split on one side and clamping bolts 18 serve to draw the two parts together and clamp the lever 15 in proper longitudinal position.

The lever 15 consists of a tube, on one end of which, as shown in Figure 6, is mounted a second telescoping tube 11. A split collar 18 serves to clamp the parts together and at the same time permit telescoping adjustment to carry the length of the operating lever. It will be noted that the operating lever 15 extends toward the operator's 2,175,057 position on the side of the' work opposite to the grinding .wheel I0, as more particularly shown in Figure 1. When the operator oscillates the lever 15, he will rotate the crank housing 10 and thereby, through the pin and roller connection, rotate the housing 65 and the sleeve 43 integrally connected therewith, whereby the pin 48 eccentricalQ ly carried on the lower end of the sleeve 43 will move in an arc about the axis of rotation of the sleeve 43 and cause axial movement of the grinding wheel spindle in either direction from its normal central position.

lWhen the grinding wheel is used to grind both the diameter and two shoulders at opposite ends of an annular groove in a work piece, it will be;

apparent that it is necessary to true the sides of the wheel as well as the peripheral surface in order to maintain square corners on the work piece. It will be Iobvious that as the sides of the 'wheel are 'trued away, the width of the wheel grows smaller whereby a greater stroke becomes necessary in order to move the sides of the wheel into contact with the shoulders and grind the width of the groove to the same size. Since the stroke of the grinding wheel is dependent upon the eccentricity of the pin 48, it will be obvious that the stroke can only be changed by varying the eccentricity of this pin. Means have therefore been provided whereby the eccentricity of this pin may be varied, and this mechanism is so contrived that it may be actuated from the operators position by means of a plunger 19 located in the end of the lever 15.

It is to be understood that the eccentricity of the pin will be a minimum when the grinding wheel is new and that as the grinding wheel wears away, the plunger is actuated to increase the eccentricity of the pin. This plunger is frictionally held in the end of a. tube 80 and may be axially adjusted -relative thereto whenever the outer telescoping sleeve 11 is adjusted relative to the lever 15 so that the plunger 19 always projects beyond the end of the tube 1. The plunger 19 comprises a tube 8| which is split on the inner end and has a taper ended draw bar 82 which is threaded in the end of the head 83 so that as the draw bar is pulled axially by rotating the head 83, the end of the tube 8U will be expanded within the tube 90 and frictionally locked.

The tube 80 carries a'collar 84, and a spring d5 n is mounted between this collar and a fixed sleeve 88 carried within the member 15. The end of the sleeve 80 has a tubular rack member 81 attached to the end thereof, as shown in Figure '1, in intermeshing relation with a pinion 88. The pinion @8 is keyed to the upper end of a shaft 89, as shown in Figure 6, and the lower end of this shaft is reduced in diameter and provided with pinion teeth 90 which intermesh with a gear segment 9|.

Referring to Figure 8, the gear segment 9| is supported for free rotation on the end of an upstanding pin 92. The segment 9| carries a radial arm 99 in the end of which a pawl 94 is pivotally mounted. A spring 95 normally urges this pawl into engagement with teeth 96 of a ring gear 91. The housing 61 has an L-shaped portion 98 surrounding the pawl and providing a shoulder 99 which is adapted to engage the heel of the pawl so that when the segment 9| is moved clockwise to its extreme position, the pawl 94 will be out of engagement with the gear teeth. Upon axial movement of the plunger 19 toward the right, as viewed in `Figure 6, the pinion 88 will be rotated and thereby through the pinion 90 will cause movement of the gear segment 9| in a counterclockwise direction whereby the heel of the pawl will move away from 4the shoulder 99 and the spring 95 will cause engagement of the pawl with the gear teeth thereby rotating the gear 91.

The gear 91v which is supported for free rotation on the pin carried by the housing 65. The segment |00 has a radial arm |02 which ts into a slot |03 of a slide |04. The slide |04 carries twin pawls |05 and |06 which are normally urged into engagement by a leaf spring |01 with teeth on the periphery of a ratchet wheel |08. The ratchet wheel |08, as shown in Figure 14, is pinned to the end of a shaft |09 which carries a worm ||0. 'Ihis worm meshesgwith a. worm wheel keyed to the upper end of shaft I2. The shaft H2, as shown in Figure 6, passes directly through the center of the sleeve 43 and is provided on the lower end with pinion teeth ||3, as more particularly shown in Figure 10. These pinion teeth mesh with a short rack bar I4 which is fastened by bolts to the slide 41.

'A second rack bar directly under the rack'bar |4 and continuously urged in one direction by a spring pressed plunger ||1 so as to take out lost motion between the pinion ||3 and the slide 41. In Figure 10, the axis of rotation of the sleeve 43 is indicated by the reference numeral ||8, and it will be noted that the rack bar moves parallel to a radial line H9 passing through the center |18 and the center |20 of the pin 48. Since the pinion l I3 is xed in space, it will be apparent that upon its rotation that the slide 41 will be moved in a direction to vary the effective eccentric radius of the pin 4E.

The amount of change that can be effected in the eccentricity of the pin for a given stroke of the plunger 19 may be made very small and is determined by the setting of two set screws |21 and |22, shown in Figure 8. These set screws urges the lever |02 in a counterclockwise direcl tion against the set screw |2| thereby returning the ratchet pawls |05 and |06 into position for the next' stroke. As the slide |04 returns these pawls to the position shown in Figure 12, the heels |24 of these pawls.engage a plate |25 thereby rotating the pawls in a clockwise direction a suicient amount to disengage them from the ratchet wheel. This makes it possible to reset the mechanism when a new grinding wheel is placed in the machine, because the shaft |09 which carries the ratchet wheel |08 projects beyond its housing, as'shown in Figure 14, and is provided with a square end |26 to which-may be applied a suitable crank for rotating the shaft |09 in a clockwise direction to effect retraction of the pin 48 toward the center ||8.

If so desired, a pair of positive stops may be provided for limiting the oscillating movement of the crank housing by providing a pair of stop screws |21 and |28 which are threaded into the housing 10 and in such position that as the housing rotates about the center of the bearing 69, the ends of the screws will alternately contact on opposite sides of the enlarged diameter |29 of pin 92. Conventional power operable means may be utilized to eiect' the movement of the grinding wheel toward and from the work meshes with a gear segment |00' Hs is mounted in the slide |33 having a reduction worm and worm gear and the rate of this movement may be controlled by a suitably formed cam |30 which, as shown `in Figure 1, is supported on a rotatable shaft |3| in adjacent relation to the under side of the sup-v port I whereby the support may be provided with a roller |32 for contacting the periphery of the cam. The cam may be actuated by a motor such a rate that one revolution of the cam will the end ofthe sleeve.

effect a complete cycle of the grinding wheel toward and from the work.

It may be desirable to effect automatic lateral movement of the grinding wheel in timed .relation to the automatic ineeding movement and e if this is desired a second control cam |31 may be applied to the shaft |3| and provided -with a spring urged follower |38 which has a lever connection |39 to a control valve |40.'

' For purposes of lillustrating one manner of obtaining automatic control, mechanism has been disclosed herein for effecting automatic lateral movement of the `grinding wheel for work that falls under the class illustrated in Figure 13. In this ca se, it is only necessary to move the wheel laterallyin one direction until the shoulder has been ground to the desired dimension after which the wheel is retracted and a new work piece substituted. g l v This movement may be effected by a piston |4| which, as shown in Figure 2, may be, slidably mounted in a cylinder |42 attached to the end of the housing 4| and in axial alignment with the sleeve 59. In order not to interfere with the spr-ing centering means*A for the sleeve, the cap4 member 62, as shown in Figure 3, may be cut away to permit the fingers |43 integral with the end of the piston |4| to pass through and engage Thus, upon admission of fluid pressure to the end of cylinder |42, the sleeve v59 will be moved and thereby through the rack and pinion connection with' the sleeve 43, the pin 48 may be moved in a direction to shift the grinding Wheel in a direction towards the shoulder 22 of the work.

The end of the cylinder |42 is connectedI by a channel |44, as more particularly shown in Figure 1, to a port of the control valve |46 which contains the valve plunger |40. This valve may have a pressure port |41 which ls supplied from a suitable source' of pressure, such as a pump |48, having an intake |49 through which fluid is withdrawn from a reservoir |50. The pump may be provided with a relief valve |5|. The plunger |40 has two annular grooves |52 and |53 whereby when the plunger |40 is shifted to the left, the port |41 will be connected to port |45 and pressure fluid will flow to the end of cylinder |42. When the plunger |40 is shifted to its right hand position, the port |45 will be connected to` an exhaust port |54 which is connected by a return channel |55 to reservoir |50. l

Thus, the admission of uid pressure to the cylinder |42 may be automatically controlled from the cam |31 and the rate of flow may be governed in accordance with the amount that the pressure port |41A is opened.

In order to limit the movement `of the sleeve 59, the opposite end of the housing 4| 4may be provided with a cup shaped member |56 inwhich' ticularlyin Figure 5.

is threaded an adjustable stop screw I |51 axially aligned with the screw |58 threaded in the end of the cap member 62 and holding one end of lthe spring 63. By adjusting the stop screw |51,

the movement of the sleeve 59 may be adjusted to thereby determine the throw ofthe spindle actuating pin 48.

In order to prevent interference from -the mechanism shown in the upper part of Figure 6 with power rotation of the sleeve 43, the pin 12, shown in Figure 8, may be withdrawn,whereby lupon rotation of the housing which is integrally connected with-,the sleeve 43, there will be no feed-back motion transmitted to the crank arm 10, and this may be, locked in position by a set screw |59 which is threaded in the housing and engageable with part of the fixed bearing 69. Additionally, thestop screw |28 may be backed away or removed to prevent interfering with the motion.

As previously mentioned, the grinding Wheel I0, shown in Figure 13, will have the face I8 as well as the face I1 periodically trued, which means that for the same starting position of the grinding wheel, the distance between the face i3 of the wheel and the face 22 of the work will gradually increase thereby normally requiring a. greater stroke in order to effect the desired contact between these surfaces so that the work may be ground. movement down to a minimum, means have been provided for limiting the return stroke to a maximum predetermined amount. The mechanism for accomplishing this is shown more parsleeve 52 is provided with a toothed block |60 and over this block and pivotally mounted on a pin |6| are pawls |62. y

The teeth onnthe block |60 are spaced a sufiicient distance apart to permit a maximum reciprocating movement of a desired amount, such as 115 of an inch or 3% of an inch, after which one of the pawls will engage a tooth so as to reduce the return movement. In other words, the st'p screw |51, shown in Figure 2,.limits the movement of the sleeve 59 in one direction, and although the spring 63 tends to return the parts in the other direction, the pawls |62 limit this return. Thus the stroke of the piston |49 is gradually reduced so that the starting position In order to keep this waste The end of the movable t:

return to the same position'each time for truing v and therefore means have been provided for releasing the pawls |62 so that the spring 63 can centralize the parts for truing. In addition, it is desirable that no inadvertent movement of the cutter spindle take place during truing and therefore means have also been provided for locking the sleeve 52. This mechanism comprises a lever arm |63 integral with the pawls and engaging a shoulder |64 on a bar |65. This bar has a threaded engagement with the end of` a vertical plunger |66. The lever arms |63 are continuously urged in a counter-clockwise direction by a spring pressed plunger |61 which also serves to hold the pawls in engagement with the teeth on the member |60. 'I'he leverarm |63 is also provided with an arm |68 which', upon clockwise rotation, will engage the sleeve 52 and lock the same.

For the purpose of merely releasing the pawls from' engagement with the teeth on member |60, the plunger |66 is simply pulled up the desired distance, and when the pawls have become disengaged from the teeth, the spring 63, shown in Figure 14, will centralize the actuating pin. If it is desired to lock the parts for any period ol time, the plunger |66 is rotated, and since thc member |65 is held against rotation by two guide screws |69 and |10, as shown in Figure 9, the member |65 will be permanently held in an upward position, which will be limited by the clamp arm |68 engaging the sleeve 52. As shown in Figure 9, the member I 65 will be permanently held in an upward position which will be limited by the clamp arm 68 engaging the sleeve 52.

As shown in Figure 9, springs lll may be provided for urging the return of the member |65 when it is merely lifted. In order to limit the axial movement of member |66, it is provided with a groove |12 into which is threaded the end of a limiting screw |13, there being sufcient lost motion between the end of the screw and the groove to permit a limited axial movement of the plunger.

There has thus been provided an improved mechanism for the purposes described whereby the spindle of a grinding machine may be manually reciprocated during power infeeding thereof toward a work piece, and that additional means have been provided whereby the spindle may be moved by power in synchronous relation to an infeed cycle, and that improved means have been provided to make the necessary adjustments and compensations for wear and truing of the grinding wheel.

What is claimed is: I

l. In a grinding machine having a support, a spindle rotatably mounted on said support, and a grinding wheel attached to said spindle, .the combination of means for eiecting axial reciprocation of said spindle during rotation thereof, including a rotatable member, a shifter carried thereby disposed eccentric to the axis of rotation of said member, means operatively connecting the shifter with said spindle, whereby upon rotation of said member, said spindle will be oscillated, and means to vary the effective eccentricity of the shifter with respect to the axis ofI rotation of the member, whereby the axial movement of said'spindle for a given angle of rotation of said member is varied,

2. In a grinding machine having a xed support,V an oscillatable support mounted on saidV xed support: a spindle journaled in saidoscillatable support and. having a grinding wheel attached thereto, the combination of means carried by said oscillatable support for reciprocating the grinding wheel spindle during rotation thereof and during movement toward a work piece, including an oscillatable member, power means for eiecting successive oscillations of said member during the grinding operation, la pin located eccentrically to the axis of oscillation, means operatively connecting the pin for axial movement of said spindle, and axially arranged means within said oscillatable member and movable relative thereto `for adjusting'the eccentricity of said pin to thereby vary the throw thereof fora given angular movement of said member.

3. In a machine tool having a xed support, an oscillatable support mounted thereon, and a grinding wheel spindle journaled in said oscillatable support and having a grinding wheel attached thereto for movement toward and from a work piece vupon movement of saidioscillatable support, the combination of a housing carried by said oscillatable support, a manually operable control lever pivotally mounted on said housing for oscillationl by the operator, motion transmitting connections carried by said housing for transmitting the motion of said lever to said spindle for effecting a limited axial movement thereof, said means including an adjustable eccentric, and means carried by said control lever and movable axially thereof for increasing the effective throw of said eccentric connection.

4. ln a grinding machine having a grindingwhe-el, a spindle therefor, and a support for mov:- ing the grinding wheel toward and from a workA piece, the combination of means carried by said support for effecting lateral movement of the grinding wheel while in engagement with a work piece to grind shoulders thereon, including a housing carried by said support, a rotatable sleeve in said housing, motion transmitting connections .from said sleeve to said spindle, means for oscillatng said sleeve, including a roller eccentrically connected to the upper end of said sleeve, a crank arm supported for rotation about an axis parallel to the axis of oscillation of said sleeve and having a pair of depending members engaging opposite sides oi said roller, and manually operable means for oscillating said crank arm..

'5. In a grinding machine having a grinding wheel, a support, and a spindle for supporting said wheel for rotation relative to said support, the combination of means for reciprocating said spindle while the grinding wheel is in engagement with said work, including a reciprocable plunger` operatively connected to said spindle, a crank arm engaging said plunger, manually operable means for oscillating said crank arm, and means normally maintaining said crank arm in a plane perpendicular to the axis of said plunger, including a tubular member, caps engaging opposite ends of said tubular member and fixed parts of the housing, and resilient means passing through said tubular member and connected atv opposite ends of said cap members.

6. In a mechanism for eiecting oscillation of a grinding wheel, a housing for supporting said grinding wheel spindle, a plunger reciprocably mounted in said housing for movement parallel to the axis of said spindle, a pair of parallel rotatable members mounted in said housing, a crank connection for transmitting rotary motion from one of said members to the other, one of said members carrying a crank pin engaging said plunger, a slide supporting said pin, means to adjust said side to vary the eccentricity o1' said pin,

' including shafts extending axially through each able by the shaft in said second sleeve for effecting a predetermined amount of rotation of said gear, and a second ratchet means operable by said gear for imparting rotation to the shaft mounted in the first sleeve,

8. In a mechanism for effecting axial moven ment of a grinding wheel spindle and attached grinding wheel supported for rotation and radial movement toward a work piece, the combination of a rotatable sleeve, an eccentric pin carried by said sleeve and operatively connected to said spindle, fluid operable means connected to said sleeve for effecting one direction of rotation thereof, and thereby one direction of axial movement of said spindle, manually operable means inlcuding a shaft passing through said sleeve for adjusting the-eccentricity of said pin, and resiliently operable means for returning said sleeve when fluid pressure lis removed from said -uid operable means.

9. In a mechanism for effecting axial movement of a grinding wheel spindle and attached grinding wheel supported for rotation and radial movement toward a work piece, the combination of a rotatable sleeve, an eccentric pin carried by said sleeve and operatively connected to said spindle, fluid operable means connected to said sleeve for effecting one direction of rotation thereof, and thereby one direction of axial movement of said spindle, manually operable means including a shaft passing through said sleeve for adjusting the eccentric'ity of said pin, resiliently operable means for returning said sleeve when fluid pressure is removed from said fluid operable means,

and means for limiting the return movement effected by said resiliently operable means when the advancing movement exceeds a predeter mined amount.

10. In a mechanism for effecting axial movement of a grinding wheel spindle and attached grinding wheel supported for rotation and radial movement toward a work piece, the combination of a rotatable sleeve, an eccentric pin carried by said sleeve and operatively connected to said spindle, fluid operable means connected to'said sleeve for effecting one direction of rotation thereof, and thereby one direction of axial movement of said spindle, manually operable means including a shaft passing through said sleeve for adjusting the eccentricity of said pin, resiliently operable means for returning said sleeve when fluid pressure is removed from said iluid operable amount.

means, and automatically operable `means for shortening the return movement when the advancing movement exceeds a predetermined 1l. A mechanism for reciprocating the grind- Aing wheel spindle of a grinding machine, including a rotatable member carrying an adjustable crank pin, motion transmitting connections connecting said pin for movement of the spindle, fluid operable means for rotating said member in one direction, resiliently operable means for rotating the member in an opposite direction, means carried by the member for increasing the eccentricity of said pin, ratchet means for decreasing the return movement of said spindle when the advancing movement exceeds a predetermined amount whereby the length of movement of said spindle will remain within prescribed limits, and manually operable means for releasing said ratchet means to permit full return u movement of said spindle.

12. A mechanism for reciprocatingthe grinding wheel Aspindle of a grinding machine, including a rotatable member carrying an adjustable crank pin, motion transmitting connections connecting said pin for movement of the spindle, fluid operable means for rotating said member in one direction, resiliently operable means for rotating the member in an opposite direction, means carried by the member for increasing the eccentricity of said pin, ratchet means for decreasing the return movement of said spindle when the advancing movement exceeds a predetermined amount, manually operable means for releasing said ratchet means to permit full return movement of said spindle, and clamping means operable by said manually operable means for holding the spindle in a, fixed position during truing operations on the grinding wheel.

13. A mechanism for effecting synchronized lateral and axial movement of a grinding wheel spindle of a grinding machine, comprising an oscillatable support for supporting the grinding wheel spindle, power operable means for moving said support in one direction to feed the grinding' wheel toward the work, including a. power driven shaft, a cam carried by said shaft and peripherally engaging said support, means carried by the support for moving the spindle laxially, including a fluid operable member, mo-

tion transmitting. connections from said member to said spindle, additional means for returning said member, a source of fluid pressure, a control valve variably positionable `for determining the rate of ilow from said source to said member, and a cam driven by said shaft for controlling the extent of variable positioning of said valve and thereby the rate of axial movement of saidv spindle.

" BERNARD A. KEARNS.

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