US3058267A

US3058267A - Automatic bit grinder

Info

Publication number: US3058267A
Application number: US785241A
Authority: US
Inventors: John A Read; John E Calmusky
Original assignee: Joy Manufacturing Co
Current assignee: Joy Manufacturing Co
Priority date: 1959-01-06
Filing date: 1959-01-06
Publication date: 1962-10-16
Anticipated expiration: 1979-10-16

Description

Oct. 16, 1962 J. A. READ ETAL AUTOMATIC BIT GRINDER 5 Sheets-Sheet 1 Filed Jan. 6, 1959 INVENTOFLQ J. AKEAD J. ECALH USKY BY ATTOIKN EY Oct. 16, 1962 J. A. READ ETAL AUTOMATIC BIT GRINDER 5 Sheets-Sheet 2 Filed Jan. 6, 1959 INVENTQ J. A. g: J. E. CALMUSKI ATTORBEY Oct. 16, 1962 J. A. READ ETAL 3,053,267

AUTOMATIC BIT GRINDER Filed Jan. 6, 1959 3 Sheets-Sheet 5 /55 I il :04 Q FIOZK 34 5 24 23 q 35 33 INVENTOFQ J 25 JAIQAD 26 J. E. cALMusw ATTORQDEY United States Patent C) 3,058,267 AUTOMATIC BIT GRINDER John A. Read, North Bay, Ontario, and John E. Cairnusiry, Gait, Ontario, Canada, assignors to lay Manufacturing Company, Pittsburgh, Pa, a corporation of Pennsylvania Filed Jan. 6, 1959, Ser. No. 785,241 17 Ciaims. (CI. 51-35) This invention relates to an automatic bit grinder and in particular to a cross bit grinder which will automatically grind each cutting edge, indexing from position to position as each edge is dressed and which will automatically compensate for the Wear of the grind ng wheel and the material removed from the bit edge during dress it cross bit of the type used in boring through rock formations has the cutting edges in the form of a cross with opposing shoulders forming a V, a pair of opposing shoulders being hereinafter referred to as V-shaped shoulders. For best results it is important that, not only to avoid wastage of the bit but to obtain an efficient drilling operation, each V-shaped shoulder should be uniformly sharpened.

One object of the invention is to provide a grinder for sharpening cross bits which will sharpen all the V-shaped shoulders to the same extent within close tolerances and which will present the cutting edges to the grinding wheel in such a manner that the wheel will not wear out of true. The accomplishment of this object requires that each surface to be ground, and in a cross bit there are four V-shaped shoulders, must be passed over the same number of times. Furthermore, as each cut is made both the wheel and metal will be reduced. Consequently the grinding wheel must be moved towards the bit, at the end of each cut by the amount of abrasive lost from the wheel and the metal removed from the bit.

When one of the \!-shaped shoulders of the bit, has been sharpened it is necessary to rotate the bit 90 and then present the next shoulder to be sharpened to the wheel. It is also necessary, at the same time, to move the grinding wheel closer to the shoulder by the amount of the grinding wheel lost in the preceding grinding position. It is therefore a further object of the invention to provide the grinder with the means which will automatically adjust the relative position of the grinding wheel and the cutting edge of the bit whereby, within close tolerance, they will be maintained in substantially the same relative position to the end that:

(1) During each cut and in each position, the grinding wheel will remove the same amount of metal.

(2) The grinding face of the wheel will follow the shoulder presented to it at each position and will make a predetermined number of passes at each position.

(3) The grinding faces of the wheel will remain true.

The foregoing and other objects are accomplished by the grinding machine described in the following specification and illustrated in the accompanying drawings which exemplify one embodiment of the invention. In the drawings:

FIGURE 1 is a perspective view with parts cut away to show operative parts of the machine, with certain parts shown in FIGURES 6 through 8 omitted.

FIGURE 2 is an end view to show the relative position of the cross bit and the grinding wheel during the grinding operation with certain parts shown in FIGURES 6 through 8 omitted.

FIGURE 3 is a schematic view of the cam mechanism for oscillating the grinding wheel and for compensating for the material lost in making the cut.

FIGURE 4 is a fragmentary view of the cross bit and grinding wheel.

ice

FIGURE 5 is a schematic view of the profile of the cam for compensating for wear projected on a flat surface.

FIGURE 6 is an elevation of the bit positioning device which is mounted on the bit holder support and shown positioning the bit.

FIGURE 7 is a side elevation showing the positioning device, partly in cross section in the same position as in FIGURE 6.

FIGURE 8 shows the positioning device moved through 90 out of contact with the bit which is its normal position during the grinding operation.

By way of explanation, the distance that the grinding wheel reciprocates is schematically indicated by the dimension B, the extent of oscillatory movement (rocking) of the wheel is schematically indicated by the dimension A and the compensation for wear is schematically illustrated by the dimension C.

The grinder illustrated in the drawings has all of its operative parts mounted on the base It). Each of the operative parts will be described in detail. They may be divided into the following units, namely,

(a) The bit holder, its mounting and the mechanism for rotating the bit holder from index position to index position through 360;

(12) The grinding unit and its mounting including the shaft on which the unit is mounted for reciprocatory and oscillatory movement;

(c) The cam devices for reciprocating and oscillating the grinding unit and for compensating for wear; and

(d) The timing mechanism and valve arrangement for controlling the air motor and for indexing the bit holder from one grinding position to the next grinding position until a complete cycle of 360 has been eifected.

Bit Holder and Related Assembly The bit holder and the related assembly comprises a support member 11 which is fastened to the base 10 and has its upper edges shaped to form a pair of parallel, spaced tracks l2, 13 extending toward the grinding wheel which is hereinafter described in detail. A feed screw 14 is mounted centrally between the tracks 12, 13 and provided with a hand wheel 15. Slidably mounted on the tracks I2, 13 is a carriage 16 which is connected to the feed screw 14 so that the carriage can he slid back and forth on the tracks by means of the feed screw, the carriage being formed with a pair of upright spaced part arms l8, 19. A bit holder support 20 having a pair of supporting

arms

21, 22 is rockably mounted on the arms I8, 19 by means of a pair of

axles

23, 24 journalled therein and is extended through the supporting

arms

21, 22. Mounted on the axle 24 on the inside end thereof is a crown gear 25 which has associated therewith a ratchet 26 and a pawl 27, the latter being pivotally mounted on the lug 28 carried on the carriage 16. With this arrangement the crown gear can only rotate in one direction, namely, counterclockwise as viewed in FIG- URE 1.

Mounted on the other shaft 23, on the outside end thereof, and keyed thereto by the key 23a is a crank arm 29. The arm 29 carries a lever arm which engages against the spaced apart stop pins 83, 84 on the arm 18 to thereby limit the movement of the crank between the two positions as hereinafter described. The means for actuating the crank arm 29 comprises a double acting fluid cylinder 30 having located therein a piston (not shown) and a piston rod 31 which has its upper end connected to the crank arm by means of a crank pin 31'. It will thus be seen that, upon actuation of the piston rod, the support 20 can be caused to rock on the

axles

23, 24 from the position shown in FIGURE 1 toward a substantially horizontal plane. As hereinafter 3 described this movement of the bit holder rotates the bit from one index position to the next as hereinafter described. The stops 83, 84 mounted on the arm 13 are engaged by the arm 85 and serve as stops limiting the up and down movement of the holder support 26.

The means for holding the bit 55 in its grinding position comprises a collet 32 which is rotatably journalled in the support 20. The collet extends through the support and has mounted on the lower end thereof a crown gear 33 which meshes with the crown gear 25. A ratchet 34 has spaced teeth corresponding in number to the number of index positions, in the present embodiment there are four teeth and, is attached to the crown gear 33. A pawl 35 is pivotally connected or mounted on the arm 21 and engages with the ratchet 34. The pawl and ratchet are constructed so that the crown gear 33 will rotate only in a clockwise direction. The upper end of the collet is formed hollow and has mounted therein a bit mount 36 which has its upper end threaded to mate with the threaded recess of the cross bit. The bit mount is provided with a set screw 38 locking the bit in position when it has been correctly aligned as hereinafter described.

The foregoing operates in the following manner. When the piston rod is actuated downwardly by the fluid pressure as hereinafter described, the support 26 is rocked in the direction indicated by the arrow applied to the arm 18 which movement rotates the pinion 33 through an angle, in the present construction, of 90. This movement rotates the collet 32 and indexes the bit to the next grinding position. When the piston rod 31 is actuated in the opposite direction the bit holder is rocked in the reverse direction so as to again present the cross bit to the grinding wheel in the next position. When moving in the latter direction the crown gear 25 rotates while the crown gear 33 remains stationary.

Grinding Unit The grinding unit includes a rotatable cam shaft 39 which is journalled in bearing blocks 40, 41 secured in the base 10. A cam housing 42 is mounted on the cam shaft to reciprocate back and forth along the shaft and oscillate (rock) forward and backward upon the shaft in the manner hereinafter described. The cam housing 42 is shaped to serve as a support for a grinding wheel 43 carried on the spindle 44 which is journalled in the cam housing 42. The spindle 44 is driven by an air motor 45 through the belt drive 46 which drives the pulley 47 mounted on the spindle 44. The drive for the cam shaft 39 comprises a worm 48 mounted on and driven by the spindle 44, a pair of spaced apart worm wheel and

worm

49, 50 mounted on the shaft 51 journalled in the cam housing 42. The worm wheel 49 is driven by the worm 48 which in turn drives the worm 50, the latter engaging with and driving a worm wheel 52 mounted on and keyed to the cam shaft 39 in such a manner that the worm wheel 52 will have reciprocating movement on the shaft in unison with the reciprocating movement of the housing 42.

The Cam Arrangements The cam arrangement for effecting the oscillating (rocking) of the cam housing hereinbefore mentioned, comprises the following elements. Mounted on the underside of the cam housing 42 is a cam follower 53 which rides over a V-cam 54 shown in FIGURE 3 and is co-related to the V-shaped shoulders of the cross bit 55 so that the total width indicated by B is equal to or slightly greater than the distance between the outside ends of a V-shaped shoulder of the cross bit and the total depth of the cam, indicated by A is equal to the height of the V. It will thus be seen that the V-cam 54 will cause the cam housing 42 to oscillate (rock) back and forth the total distance A while reciprocating through distance B.

Reciprocating movement of the housing 42 is induced 'by means of an endless helical cam 56 cut in the cam shaft 39 and a cam follower 57 carried by the cam housing 42. The overall length of the cam 56 is equal to the distance 13" indicated in the drawings. The cam housing is counter-balanced by means of a tension spring 58 whereby the cam follower 57 works against the spring tension. The V-cam 54 is slidably mounted in the block 59 and has its inner end chamfered as indicated at 60, the chamfered end riding against a cam plate 61 which is mounted on the ratchet wheel 62 which will be described in relation to the timing devices, and indexing. The cam plate 61 has four cam sections corresponding and related to the four index positions. The cams provide a means for allowing the grinding wheel to progressively move closer and closer to the bit in an amount equal to the material lost from the wheel. The compensation on these cams for wheel wear is by having one cam a little higher than the other progressively, thus each cam will have the same rise, however, the beginning depth of advance of each cam is progressively forward of the preceding one to account for the wheel wear.

Timing Device, Indexing and Valve Arrangements The timing device, for the purpose of illustrating the invention, includes the ratchet wheel 62 which is rotatably mounted on the bearing block 63 and it carries four cam members 64 at 90 intervals and a stopping cam 65 located to shut down the machine at the end of each complete cycle of four index positions. The ratchet wheel 62 is driven in the following manner. Mounted on and rotating with the cam shaft 39 is a two-lobed cam 66 on which the cam follower 67 rides, the cam follower being mounted on a slidable rod 68 which in turn actuates a pawl 69 to move the ratchet wheel one increment in one direction. The idler pawl 70 which engages With the ratchet wheel 62 prevents the wheel 62 rotating in a reverse direction.

The position of cam follower 67 relative to the cam may be adjusted by means of the adjusting screw 68a whereby the advance of the ratchet wheel 62 may be controlled as described.

In order that the ratchet wheel may be advanced manually there is provided a hand operated cam 71 which over-rides the two-lobed cam 66 pulling its follower 67 in the direction to rotate the ratchet wheel 62 sufficient to start the machine as hereinafter described. In that position, since the cam follower is held out of contact with the lobes on the cam 66, no cycling of the indexing or timing mechanism takes place until the starting cam 71 is returned to the run position in which position it is shown in FIGURE 1. .In order that the hand operated cam may be turned manually, it is provided with an operating handle 72. By this means the operator may therefore start up the grinding wheel and adjust the bit for y the first cut in the first index position before letting the automatic operation take over.

Fluid Pressure System and Valve Mechanism The delivery of the fluid pressure for driving the air motor 45 and for reciprocating the piston rod 31 is controlled by a control valve 73 mounted on the bracket 74 carried by the bearing block 63. Air pressure is delivered to the control valve by the conduit 75 which is connected to a suitable supply of air pressure and controls the delivery of air pressure to the air motor through the conduit 76 and to the cylinder 30 through the

conduits

77, 78.

The delivery of air under pressure to the air motor 45 through the conduit 76 is controlled by a reciprocating valve 79 having a valve stem 80 extending through and actuated by the stopping cam 65. In the position shown in FIGURE 1, the valve 79 has uncovered the inlet to the conduit 76 and the valve stem is in a position to commence the cycle of operation. When the outer end of the valve stem 80 rides onto the cam 65, the valve 79 will be reciprocated to close the inlet to the conduit 76 and thus stopping the grinder. When the valve stem is released from its engagement with the cam 65 by manual operation of the hand operated cam, the air pressure in the line will move the valve to its open position and deliver air pressure to the air motor.

The delivery of air pressure to the cylinder 30 is controlled by the reciprocating valve 81 which is provided with a valve stem 82 which is actuated by one of the cams 64 in one direction to shut off the supply of air pressure through the conduit 77 to the bottom of the cylinder 30 and at the same time open the inlet to the conduit 78 for the supply of air pressure to the top of the cylinder and thus cause the downstroke of the piston rod 31. When the stem 82 has ridden over one of the cam lobes 64 the air pressure supply will reciprocate the valve 81 in the opposite direction to close the inlet to the conduit '7 8 and open the inlet to the conduit 77 and thus supply air pressure to the bottom of the cylinder to give the upstroke of the piston rod 31. It will be seen from this arrangement that the bit is held in the sharpening position by fluid pressure.

Positioning Device and Lock Out Valve Mechanism In order that the bit may be properly positioned and aligned relative to the grinding face of the grinding wheel 43 a positioning device is mounted on the support 20.

The positioning device is illustrated in FIGURES 6, 7 and 8 and includes a support member 90 rising vertically from the support 20 and terminating in a pair of spaced apart arms 91, only one of which is shown in the drawings. Mounted in and extending across the arms 91 is a pivot 92 on which is pivotally mounted a positioning support member or lever arm 93 of sufiicient length, when in the horizontal position, to extend over the bit 55. The end of member 93 which overlies the bit, carries a pair of aligned bit positioners or bit

engaging pins

94, 95, the positioners being carried on a support 96 pivotally mounted between the forked ends 97, 93 of the support member 93. When the positioning support member 93 is swung to a horizontal position as shown in FIGURE 7, the

members

94, 95 ride down the relatively inclined faces of the bit and with a wedging action rotate it so that the bit is correctly aligned with the grinding wheel 43. When aligned, the set screw 38 is tightened to secure the bit in its set position.

The positioning device is operated by means of a toggle clamp comprising a hand lever 113 which is bifurcated to straddle the support member 93. The lower end of the lever 113 is pivotally attached to the support 90* below the pivot 92 and slightly forward thereof. A link 99 connects the lever 113 to the member 93, the pivot points of the lever 113 and the link 99 being in the same vertical plane when the lever is moved to a vertical position, which movement brings the member 93 to a horizontal position thus to provide a self locking toggle. A stop 114 carried by the member 93 positions the lever 113 in the correct vertical position. The lever is pulled backwards to swing the arm 93 completely clear of the bit during the grinding operation by means of a pair of tension springs 100, 101, on each side of the lever and connected to the lever 113 and support 90 so that a slight touch on the lever, in the direction of the arrow, FIGURE 7, will unbalance'the toggle and permit the arm and lever under the influence of the

springs

100, 101, to swing from the position shown in FIGURE 7 to the position shown in FIGURE 8.

In order that the grinding machine cannot be operated while the positioning device is in use, that is in the horizontal position shown in FIGURE 7, a lock out device is associated with the positioning device. The lock out device comprises a valve chamber 102 formed in the support 90; a valve disc 103, a valve seat 104 and a compression spring 105, a valve stem 106 extending vertically through the support and of sufficient length to be engaged and depressed by the member 93 when it is in the horizontal position. The valve chamber 102 has a discharge 6 port 107 opened by the unseating of the valve disc 104, and an inlet 10% which is in communication with the control valve 73 through a conduit 109.

Air Cooling and Oil Separation The grinding wheel is cooled by air from the exhaust of the air motor. For this purpose, a conduit 110 (FIG. 2) is connected to the discharge outlet of the air motor 45 and delivers it to an oil filter 111. Then the motor discharge is directed against the wheel 43 by means of a conduit 112.

Operation The :grinder operates in the following manner to initiate the grinding operation. The operator moves the handle 72 to the starting position which actuates the ratchet wheel 62 to the starting position in which position both stems 80, 82 move out of engagement with their respective cam lobes. This permits fluid pressure to be delivered to the air motor 45 which thereupon commences to drive the grinding wheel 43. The turning of the starting cam moves the cam follower 67 out of contact with the cam lobes on the cam 66 so that the machine will run without indexing. The operator then turns the hand wheel 15 to adjust the carriage 16 to position the bit 55 for the first cut. As soon as that has been accomplished the operator then returns the starting cam back to its original position which allows the mechanical indexing to take over.

The cams 54, 56 cause the grinding wheel and its mount to reciprocate and oscillate (rock) with the result that the grinding wheel follows the V-shaped profile of the shoulders of the bit. The cam 61 which presses against the V-cam 54 causes the grinding wheel to be fed slowly towards the bit during grinding. When the valve stem passes over one of the cam lobes 64, in the next position, the bit holder support 20 will be rocked on its shaft 23 causing the collet 32 and bit 55 to be rotated through 90. When the index ratchet 62 has turned through a full 360 the valve stem will ride up the cam lobe 65 shutting down the grinder.

The operation of the positioning device has already been described. The lock out valve is automatically unseated when the bit positioning member 93 is brought into the position shown in FIGURE 7 to position the bit. Such action on the part of the operator places the whole machine in an inoperative condition by bleeding oif the air from the valve 73. This is important for the safety of the operator. The machine cannot be placed in an operative condition without the deliberate action of the operator. Such action consists of the operator striking the lever 113 to move it sufficiently to unbalance the toggle. The

springs

100, 101, then snap the lever and member 93 back to the position shown in FIGURE 8. The release of the member 93 automatically closes the lock out valve by permitting the valve disc 103 to seat. This in turn allows the air (pressure fluid) to follow its normal path to the air motor and indexing device as previously described.

The foregoing describes a specific construction of a grinder that has been built for use in dressing a cross bit which has equal angles between the cutting edges. However, the grinder can be modified within the scope of the invention and appended claims to grind bits which have different angles between the cutting edges. It will be apparent to those skilled in the art that by modifying the cam structure and the timing mechanism the grinding wheel can be made to follow the profile of the cutting edges of a bit whether there be more or less than four and even though they are spaced with diiferent angles between them.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What we claim as new and desire to secure by Letters Patent is:

1. In a fluid operated bit grinder, a grinding wheel, a rotatable bit holder, a bit holder support mounted on a carriage for rocking movement towards and away from said grinding wheel, indexing means responsive to said rocking movement on said holder, said carriage mounted on a base, manually operated means mounted on said carriage connected to said support for initially presenting a cutting edge of the bit to said grinding wheel, fluid actuated means operatively connected to said support for rocking said support for rotating said bit holder through a number of index positions, a mounting for said wheel, said mounting being mounted on a rotatable shaft for reciprocation and oscillation movement relative to said shaft, said shaft journaled on said base, a fluid motor rotating said shaft and driving said wheel, cam means oscillating said mounting on said shaft, other cam means mounted on said shaft operatively engaging said mounting for reciprocating said mounting, valve means mounted on said base controlling the delivery of fluid pressure to said fluid motor and to said fluid actuated means, cam means rotatably mounted on said base for operating one of said valve means to shut oil the fluid pressure to said motor at a predetermined setting of said last mentioned cam and said last mentioned cam operating other of said valve means to actuate said first mentioned fluid actuated means to move said bit holder away from said wheel, turn said holder through an angle equal to the angle between two adjacent index positions and present the next cutting edge to the wheel.

2. In an automatic bit grinder according to claim 1 including a cam having lobes equal in number to the number of index positions, each lobe being shaped to advance the grinding wheel to the cutting edge by an amount approximately equal to the amount of grinding material and metal lost in each cut.

3. An automatic bit grinder according to claim 1 including means for adjusting the duration of each complete operating cycle of the grinder.

4. In an automatic bit grinder according to claim 1 including a manually actuated cam member engageable with a cam follower associated with the indexing mechanism to advance the indexing mechanism to the starting position.

5. In a fluid operated bit grinder, a rotatable bit holder in which a cross bit is mountable, a bit holder support mounted on a carriage for rocking movement towards and away from a grinding wheel, manually operated means for initially presenting a cutting edge of the bit to the grinding wheel, fluid actuated means rotating said bit holder through a number of index positions, a grinding wheel, a mounting for said wheel, the mounting being mounted on a rotatable shaft for reciprocation and oscillation movement, a fluid motor rotating said shaft and driving said wheel, cam means reciprocating and oscillating said mounting on said shaft, said cams cooperating to move said wheel in a path to follow the profile of the cutting edge during each complete cut, valve means controlling the delivery of fluid pressure to said fluid motor and to said fluid actuated means, cam means operating one of said valves to shut off the fluid'pressure to said motor when the bit holder 'has been turned through 360 and the other of said valves to actuate said first mentioned fluid actuated means to move said bit holder away from the wheel, turn said holder through an angle equal to the angle between two adjacent index positions and present the next cutting edge to the Wheel, a pivotally mounted positioning device for positioning the cross bit, said positioning device being manually swingable to engage and rotate said cross bit to align with said grinding Wheel, and spring means urging said positioning device out of engagement with the cross bit.

6. In an automatic bit grinder according to claim 5 including a valve operatively connected to said valve means and arranged to by-pass fluid pressure to atmosphere when open, a valve stem positioned to be engaged by said positioning device when it is swung to position the bit whereby said valve is unseated to render the machine inoperative during the time that the positioning device is in engagement with the bit.

7. In a fluid operated bit grinder, a rotatable bit holder in which a cross bit is mountable, a bit holder support mounted on a carriage for rocking movement towards and away from a grinding wheel, manually operated means for setting the cutting edge of the bit relative to the grinding wheel at the commencement of the grinding cycle, fluid actuated means for rotating said bit holder through four index positions, a grinding wheel, a mounting for said wheel, said mounting being mounted on a rotatable shaft for simultaneous reciprocation and oscillation move ment, a fluid motor rotating said shaft and driving said wheel, cam means simultaneously reciprocating and oscil lating said mounting on said shaft, said cams cooperating to induce said wheel to follow the profile of the cutting edge during each complete cut, valve means controlling the delivery of fluid pressure to said fluid motor and to said fluid actuated means, cam means operating time of said valves to shut oflf the fluid pressure to said motor when the bit holder has been turned through 360 and the other of said valves to actuate said first mentioned fluid actuated means to move said bit holder away from the wheel, turn said holder through an angle equal to the angle between two adjacent index positions and present the next cutting edge to the wheel, a pivotally mounted positioning device for positioning the cross bit, said posi tioning device being manually swingable to engage and rotate said cross bit to align with said grinding wheel, and spring means urging said positioning device out of engagement with the cross bit.

8. An automatic bit grinder according to claim 6 including an air conduit having one end connected to the discharge of the air motor and the other end positioned adjacent to said wheel and an oil separator disposed in said conduit whereby cool, oil free air is directed against said wheel.

9. An automatic bit grinder according to claim 7 including an air conduit having one end connected to the discharge of the air motor and the other end positioned adjacent to said wheel and an oil separator disposed in said conduit whereby cool, oil free air is directed against said wheel.

10. In an automatic bit grinder having an elongated base, a Work holder supported on said base, said holder being indexed about an axis that is transverse to said elongated base, a rotatable shaft mounted on said base with its axis of rotation subtantially perpendicular to said index axis, a housing slidably mounted on said. rotatable shaft, a rotatable grinding wheel mounted on said housing for machining a work piece held by said work holder, means mounted on said housing for rotating said wheel and said shaft, means on said rotatable shaft cooperative with means on said housing for reciprocating said housing and said wheel on said shaft, feed means mounted on said base cooperative with said housing for oscillating said housing on said shaft to perform a machining operation on the work piece held by said Work holder, cam means mounted on said base cooperative with said feed means for controlling the depth of cut of said feed means, and said cam means having linkage means cooperative with said shaft for actuating said cam means.

11. A grinder as set forth in claim 10 wherein said cam means comprises a series of control elements wherein each control element is tapered progressively to advance said feed means.

12. A grinder as set forth in claim 11 wherein each series of control elements has the same taper but are incrementally greater in depth.

13. In a machine having an elongated base for supporting a work holder, means for indexing said work holder about an axis that is transverse to said elongated base, a rotatable shaft mounted on said base with its axis of rotation substantially perpendicular to said index axis, a housing slidably mounted on said rotatable shaft, a rotatable grinding wheel mounted on said housing for machining a work piece held by said work holder, means mounted on said housing for rotating said wheel and said shaft, means on said rotatable shaft cooperative with means on said housing for reciprocating said housing and said wheel on said shaft, template control means mounted on said base cooperative with a follower on said housing for oscillating said housing on said shaft to perform a machining operation on the work piece held by said work holder, cam means mounted on said base cooperative with said template means for controlling the position of said template means, said cam means having linkage means cooperative with said shaft for actuating said cam means.

14. In a machine having an elongated base for supporting a work holder, means for indexing said work holder about an axis that is transverse to said elongated base, a rotatable shaft mounted on said base with its axis of rotation substantially perpendicular to said index axis, a housing slidably mounted on said rotatable shaft, a rotatable grinding wheel mounted on said housing for machining a work piece held by said work holder, means for rotating said wheel and said shaft, means on said rotatable shaft cooperative with means on said housing for reciprocating said housing and said wheel on said shaft, contour control means mounted on said base operative with follower means on said housing for oscillating said housing and said wheel on said shaft as said housing and said wheel are reciprocated on said shaft, cam means mounted on said base for controlling the position of said control means, said cam means having linkage means cooperative with said shaft for actuating said cam means.

15. In a machine as set forth in claim 14 wherein said cam means comprises a series of sequentially operated cam elements, and each element having the same contour with each successive element being of incrementally greater depth to compensate for wear of said wheel.

16. In an automatic bit grinder, a rotatable bit holder, a bit holder support mounted for rocking movement towards and away from a grinding wheel, said bit holder mounted on said support, means for rotating said bit holder step-by-step through a number of index positions, a power driven grinding wheel, a mounting for said wheel, said mounting being mounted on a rotatable shaft for reciprocating and oscillating movement relative to said shaft, power means for rotating said shaft and driving said wheel, cam means simultaneously reciprocating and oscillating said mounting on said shaft, cam actuated means selectively operable to actuate said first mentioned means through a complete cycle of index positions equal in number to the number of index positions and means stopping the grinder when the bit holder completed the cycle of index positions wherein said cam actuated means comprises a cam mounted on and rotated by said shaft, a reciprocable rod having a cam follower mounted on one end to be engaged by said cam, a pawl carried by said rod, a ratchet wheel rotated by the said pawl, cam lobes carried by said wheel at uniformly spaced intervals and corresponding in number to the number of index positions, a fluid valve mechanism operated by said cam lobes, and a reciprocable member operatively connected to said bit holder support and selectively reciprocated by said valve mechanism to thereby rock said bit holder support.

17. In an automatic bit grinder, a rotatable bit holder, a bit holder support mounted for rocking movement towards and away from a grinding wheel, said bit holder mounted on said support, means for rotating said bit holder step-by-step through a number of index positions, a power driven grinding wheel, a mounting for said wheel, said mounting being mounted on a rotatable shaft for reciprocating and oscillating movement relative to said shaft, power means for rotating said shaft and driving said wheel, cam means simultaneously reciprocating and oscillating said mounting on said shaft, cam actuated means selectively operable to actuate said first mentioned means through a complete cycle of index positions equal in number to the number of index positions and means stopping the grinder when the bit holder completed the cycle of index positions wherein said cam actuated means comprises a cam mounted on and rotated by said shaft, a reciprocable rod having a cam follower mounted on one end to be engaged by said cam, a pawl carried by said rod, a ratchet wheel rotated by the said pawl, cam lobes carried by said wheel at uniformly spaced intervals and corresponding in number to the number of index positions, a fluid valve mechanism operated by said cam lobes, and a reciprocable member operatively connected to said bit holder support and a manually actuated starting cam engageable with and actuating said rod whereby said ratchet wheel is moved to its starting position.

References Cited in the file of this patent UNITED STATES PATENTS 641,107 Heister Jan. 9, 1900 1,905,094 Hirvonen Apr. 25, 1933 1,982,050 Gleason et al Nov. 27, 1934 2,055,361 Oliver Sept. 22, 1936