US2660838A - Cam grinding machine - Google Patents

Description

1953 c. J. GREEN 2,660,838

CAM GRINDING MACHINE Filed Dec. 17, 1950 6 Sheets-Sheet 1 CLARE/v5: =J. GREEN By ATT'or-ney I9 70 a 77 I w {I I5 i4 8/ a 79 l nven o 1953 c. J. GREEN 2,660,838

CAM GRINDING MACHINE Filed Dec. 17, 1950 6 Sheets-Sheet 2 I] Inverfl'br CLARENCE :J. GREEN By A Tfor-ne Dec. 1, 1953 c. J. GREEN CAM GRINDING MACHINE 6 Sheets-Sheet 3 Inver/Tor A RENEE IL/- GREEN By 'Afforney Filed Dec.

Dec. 1, 1953 c. J. GREEN 2,660,838

CAM GRINDING MACHINE Filed Dec. 17, 1950 e Sheets-Sheet 6 764 v 27 V v 774 277 17a FIG '1 7 1 78 I-n\/ enTor CLARENCE 1-J. GREE Patented Dec. 1, 1953 UNITED STATES PATENT OFFICE CAM GRINDING MACHINE Clarence J. Green, Worcester, Mass, assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application November 17, 1950, Serial No. 196,263

13 Claims. 1

The invention relates to grinding machines, and more particularly to an automatic cam grinding machine for grinding a plurality of spaced integral cams on a camshaft to predetermined contours and tapers.

One object of the invention is to provide a simple and thoroughly practical automatic cam grinding machine to grind a plurality of cams which taper in opposite directions. Another ob ject of the invention is to provide a grinding machine having a rotatable work: support on a longitudinally movable swivel table with an automatically actuated mechanism for swivelling the table in opposite directions to facilitate grinding opposite tapers on spaced portions of a workpiece. Another object is to provide a cam grinding machine having a longitudinally movable swivel table with a swivelling mechanism which is actuated automatically by and in timed relation with the longitudinal movement of the table successively to swivel the swivel table in opposite directions to grind oppositely tapering surfaces on certain of the cams being ground.

A further object of the invention is to provide a suitable wheel feeding mechanism having a table actuated stop mechanism for limiting the infeeding movement of the grinding wheel to compensate for the swivelling movement of the table. Another object of the invention is to provide a master cam assembly with stepped master cams which are arranged to compensate for the swivelling of the swivel in grinding oppositely tapering surfaces on spaced cams on a camshaft.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which willbe indicated in the following claims.

In the accompanying drawings in which is shown one of various possible embodiments of the mechanical features of the invention,

Fig. 1 is a front elevation of a grinding machine.

mately on the line 44! of Fig. 3, through the wheel slide and wheel slide base;

Fig. 5 is a fragmentary sectional view, on an enlarged scale, taken approximately on the line 55 of Fig. 4, showing the fluid motor for rapidly positioning the wheel slide;

Fig. 6 is a fragmentary vertical sectional view, on an enlarged scale, taken approximately on the line 66 of Fig. 3, showing the star wheel and dog indexing mechanism;

Fig. '7 is a fragmentary plan view, on an enlarged scale, of the hydraulically operated mecha-' nism for swivelling the worktable;

Fig. 8 is a fragmentary front elevation, taken approximately on the line 8-8 of Fig. 7;

Fig. 9 is a fragmentary sectional detail view, on an enlarged scale, taken approximately on the line 9--9 of Fig. 7;

Fig. 10 is a fragmentary sectional detail view, on an enlarged scale, taken approximately on the line ill-10 of Fig.7;

Fig. 11 is a fragmentary detail view, on an enlarged scale, taken approximately on the line H- l I of Fig. 7;

Fig. 12 is a fragmentary rear elevation, on an enlarged scale, of the rotary feed stop disc for positioning the wheel slide;

Fig. 13 is a fragmentary plan view, on an mechanism;

Fig. 14 is a diagrammatic view showing the worktable swivelled in a counter-clockwise direction for grinding cams I, 2, 5 and 6 with faces tapering toward the right;

Fig. 15 is a similar diagrammatic view showing the worktable swivelled in a clockwise direction for grinding cams 3, 4, I and 8 with faces tapering toward the left;

Fig. 16 is a combined hydraulic and electrical diagram of the operating mechanisms and the controls therefor;

Fig. 1'7 is a hydraulic diagram of the wheel feeding mechanism;

Fig. 18 is a diagrammatic view of a modified construction, showing the swivel table swivelled in a counter-clockwise direction in which stepped master cams are utilized; and

Fig. 19 is a similar diagrammatic view showing the swivel table swivelled in a clockwise direction.

An automatic cam grinding machine has been illustrated in the drawings comprising a base l0 which supports a longitudinally movable -work-.

table H on the usual fiatway l2 and V-way l3 formed on the upper surface of the base I 0. The longitudinally movable table I I supports a swivel table [4 which is arranged to pivot on a stud l5.

The base It also supports a transversely movable wheel slide l6 which is arranged to slide transversely on a V-way l1 and a flat/Way l8 formed on the upper surface of a transversely movable wheel slide base I9. The wheel slide base I9 is in turn supported on a V-way '28 and a fiatway 2| formed on the upper surface of the base Ill. The wheel slide I6 is provided with a rotatable wheel spindle 22 journalled in bearings (not shown). The wheel spindle 22 supports a rotatable grinding wheel 23'. A suitable driving mechanism is provided for driving the wheel spindle 22 and the grinding wheel 23 comprising an electric motor 24 adjustably mounted on the upper surface of the wheel slide 16. The motor 24 is connected by a V-belt drive (not shown) contained within a belt guard 25 (Figs. 1 and 2).

The swivel table 14 serves as a support for a pivotally mounted rock bar which is pivotally supported by a plurality of spaced bearing brackets 3| and 32 which are in turn fixedly mounted on the upper surface of the swivel table I4. The rock bar 30 serves as a support for a master cam spindle 33 which extends within a headstock housing 29. The master cam spindle 33 is provided with a camshaft supporting center 34 for supporting the left-hand end of a camshaft 35 to be ground. The rock bar 30 also supports a footstock 36 having a footstock center 31 for supporting the right-hand end of the camshaft 35.

The master cam spindle 33 may be driven by an electric motor 38 (Figs. 1 and 2) mounted on the upper surface of the headstock housing 29. The motor 38 is drivingly connected in a manner (not shown) positively to rotate the master cam spindle 33 and the camshaft 35 to be ground. The master cam spindle 33 is provided with a plurality of master cams 39 which are arranged to be successively engaged by a master cam follower roller 40, which is slidably supported on a rotatable shaft 4|, for controlling the rocking movement of the rock bar 30 so as to generate predetermined contours on the cams being ground. This mechanism is not considered to be a part of the present invention and therefore has not been illustrated in detail. The drive for the master cam spindle 33 and the arrangement of the master cams 39 and the follower roller 49 may be substantially the same as that shown in the prior U. S. Patent No. 2,185,837, to G. Crompton, Jr., dated January 2, 1940, to which references may be had for details of disclosure not contained herein.

A suitable mechanism is provided for rapidly moving the wheel slide 66 relative to the wheel slide base [9 to cause a rapid approaching movement of the grinding wheel 23 to and from an operative position relative to the camshaft 35 to be ground. This mechanism may comprise a fluid pressure cylinder which is fixedly mounted on the wheel slide base l9. The cylinder 45 contains a slidably mounted piston 46 which is connected to one end of a piston rod 41. The other end of the piston rod 4'! is connected to a de' pending bracket 48 which is fixedly mounted on the underside of the wheel slide [6.

Due to the swivelling of the swivel table I 4 for grinding tapered cams, to be hereinafter described, a suitable stop mechanism is provided to limit the forward approaching movement of the wheel slide Hi. This mechanism may comprise a rotatable shaft 50 (Fig. 3) which is journalled in a pair of spaced bearings 5! and 52 in the wheel slide base I9. A plate 53 is fixedly keyed on the right-hand end of the shaft 50. The plate 53 is provided with a plurality of spaced adjustable stop studs 54 which are arranged to be indexed into an operative position in the pathv of a bracket 55 which is fastened to the right-hand 4 end of the wheel slide l6 (Fig. 3). A shaft 55 is journalled in a bearing 51 which is fixedly mounted within the wheel slide base IS. The shaft 55 is slidably keyed within a central aperture formed within the left-hand end of the shaft 50. A gear 58 is mounted on the left-hand end of the shaft 56 and meshes with a gear 59 mounted on a rotatable shaft 60. The shaft 60 is journalled in a bearing 6! which is fixedly mounted relative to the base Ill. The shaft 60 is also provided with a star wheel 62 (Figs. 3 and 6) which is arranged in the path of a plurality of adjustably spaced dogs 63. The dogs 63 are adjustably mounted on the rear surface of the worktable II. A T-slot B4 is formed in the rear edge of the table H to facilitate supporting and adjusting the dogs 63. The mechanism just described is provided to regulate the extent of a rapid approaching movement of the wheel slide 16 when the swivel table 14 is swivelled for taper cam grinding. The stops 54 are numbered 1 to 8 inclusive to correspend with the cams l to B on the camshaft 35.

In order to obtain a predetermined controlled feeding movement of the grinding wheel 23, a suitable feeding mechanism is provided comprising a rotatable feed screw 10 which is journalled in bearings H and I2 fixedly mounted relative to the base [0. A depending half-nut T3 depends from the under side of tne wheel slide base I9 and meshes with or engages the feed screw 10. A suitable mechanism is provided comprising manually operable feed wheel 19 for manually rotating the feed screw 10. The feed wheel 79 is mounted on the front of the machine base. A micrometer feed adjusting mechanism an is provided of the well known type, such as for example that shown in the expired U. S. patent to C. H. Norton, No. 762,838, dated June 14, 1904, to which reference may be had for details of disclosure not contained herein. This micrometer feed adjusting mechanism 80 serves to facilitate precisely adjusting a stop abutment not shown relative to a pivotally mounted stop pawl 81 which is pivotally supported on the front of the machine base I0.

A suitable power operated mechanism is provided for automatically rotating the feed screw 10 to impart a feeding movement to the grinding wheel 23. This mechanism may comprise a hydraulic cylinder 16 (Fig. 1'7) which contains a slidably mounted piston 11. A rack bar 18 is formed on the upper surface of the piston 11 and meshes with a gear 15 mounted on the end of the shaft 14. The gear 15 meshes with a gear (not shown) mounted on the forward end of a shaft 14a (Fig. 3). This feeding mechanism is substantially identical with that shown in the prior United States Patent No. 2,522,485 to Herbert A. Silven et al., dated September 12, 1950, to whichreference may be had for details of disclosure not contained herein. It will be readily apparent from the foregoing disclosure that movement of the piston 11 caused by fluid admitted to the cylinder 16 will impart a rotary motion to the gear 15 and through the shaft 14 will transmit a corresponding rotary motion to the shaft 14a and the feed screw 10.

In order to operate the machine automatically the table II is preferably moved longitudinally by a hydraulic mechanism comprising a cylinder 85 which contains a slidably mounted piston 86. The piston 86 is connected tothe left-hand end of a piston rod 81 (Fig. 16). The right-hand end. of the piston rod 81 is connected by a, bracket 88 which is fixedly mounted on the under side of the table II. It will be readily apparent that when fluid under pressure is passed through a pipe 89 into a cylinder chamber 90, the piston 86 together with the table II will be moved toward the right. During this movement, fluid within a cylinder chamber 9| may exhaust through a pipe 92. Similarly when fluid under pressure is adv mitted through the pipe 92 into the cylinder chamber 9 I, the piston 86 together with the table I I will be moved toward the left.

An automatic control mechanism may be provided for controlling the admission of fluid to the cylinder 85 for automatically indexing the table II successively to position cams on the camshaft 35 to be ground into operative relation with the grinding wheel 23. This mechanism is not con-. sidered to be a part of the present invention and consequently has not been illustrated in detail. This mechanism may be substantially identical with that shown in the prior U. S. Patent No. 2,185,837, above referred to, to Which reference may be had for details of disclosure not contained herein.

In modern practice in grinding camshafts for the automotive industry, it is desirable to grind cams not only having a predetermined contour but also tapering from side to side so that when installed in an automotive engine, the rotation of the cam on the valve tappet will cause a rotary motion to be imparted to the tappet. In some automotive engine designs it is necessary due to arrangement of the valves and tappets to provide cams having peripheral surfaces tapering in opposite directions. In some cases it is desirable to provide a taper toward the left on all cams on the left-hand end of the camshaft 35 and to provide a taper toward the right on the remainder of the cams on the right-hand end of the camshaft 35. As illustrated in the drawings the machine is set up for grinding alternate pairs of cams tapering in the opposite direction. In order to accomplish this desired result, a hydraulically operated mechanism is provided for swivelling the swivel table I4 about its pivot stud in a clockwise direction or counterclockwise direction so as to produce the desired taper on the cam being ground. This mechanism may comprise a hydraulic cylinder 98 which is fixedly mounted on the longitudinally movable table II. The cylinder 98 contains a slidably mounted piston 99 which is connected to one end of a piston rod I00. The other end of the piston rod I is reduced slightly in diameter and passes through an elongated hole IIlI formed in a, block I02 (Fig. 10). The block I02 is pivotally supported on a stud I03 which is fixedly mounted on a bracket I94 fastened to the left-hand end of the table II (Figs. 7 and 9-). The piston rod I09 passes through a clearance hole I05 in the stud I03. The elongated hole IOI and the clearance hole I05 are provided to facilitate a free swivelling movement of the table I4 when fluid under pressure is admitted to the cylinder 98.

When fluid under pressure is passed through a pipe I09 into a cylinder chamber I01 (Fig. 7) the piston 99 is moved downwardly to impart a counter-clockwise swivelling movement to the swivel table I4. During this movement fluid within a cylinder chamber I08 may exhaust through a pipe I09. A pair of throttle valves I I0 and I I I are provided respectively in the pipes I09 and I09 to facilitate controlling the speed of movement of the piston 99 and the swivelling movement of the swivel table I4. Similarly when fluid under pressure is passed through the pipe (ill I09 into the cylinder chamber I08, the piston 99 will be moved upwardly (Fig. 7) thereby swivelling the swivel table I4 in a clockwise direction.

It is desirable to provide precise means for limiting the swivelling movement of the swivel table I4 in either direction to facilitate grinding predetermined tapers in opposite directions on the cams being ground. The worktable II is provided with a pair of spaced upwardly projecting lugs H5 and H6. The lugs H5 and H6 are provided with adjustable stop screws II! and H8 respectively which are arranged in the path of a stop lug I I9 which is fastened to the left-hand end of the swivel table I4. By manipulation of the stop screws Ill and II 9, the clockwise and counter-clockwise swivelling of the swivel table I4 may be precisely controlled.

The actual taper produced on the cams being ground is very slight for example a small frac tion of one degree. This taper has been somewhat exaggerated in the drawings (Figs. 14 and 15) to clarify the illustration. As shown in Fig. 14, the swivel table I4 is swivelled in a counterclockwise direction to illustrate diagrammatically the relative position of the camshaft 35 and the grinding wheel 23 while grinding cams I, 2, 5 and 6. Similarly in Fig. 15, the swivel table has been swivelled in a clockwise direction to show diagrammatically the relative position of the camshaft 35 and the grinding wheel 23 while grinding cams 3, 4, I and 8 on the camshaft 35. It will be readily apparent from the foregoing disclosure that cams I and 2 are ground while the swivel table I4 is swivelled in a counterclockwise direction after which the table is swivelled in a clockwise direction for grinding cams 3 and 4. The swivel table I4 is again swivelled in a counter-clockwise direction to position the camshaft 35 for grinding'cams 5 and 6 after which the swivel table is again swivelled in a clockwise direction to position the camshaft 35 for grinding cams l and 8 so that alternate pairs of cams will be ground tapering in opposite directions.

It is desirable to provide a wheel spindle reciprocating mechanism for reciprocating the grinding wheel spindle 22 axially within its bearings during a grinding operation. This mechanism may comprise a worm I25 (Fig. 13) mounted on the wheel spindle 22. The worm I25 meshes with a worm gear I25 mounted on a vertical shaft I27. The vertical shaft I2! is provided at its upper end with an eccentric stud I28 which supports an eccentric disc I29. The eccentric disc I29 is surrounded by one partof a connecting rod I30. The connecting rod I30 is provided with a yoked end I3I which engages a stud I 32 carried by a pivotally mounted yoked member 533. The yoked member I33 is pivotally supported on a stud I34 which is fixed relative to the wheel slide I5. A tension spring I35 is connected between a stud I35 on the yoked member I 33 and a stud I31 fixedly mounted within the wheel slide I9. The spring I35 serves normally to maintain the stud I32 positioned within the yoke I3I. The yoked member I33 is provided with opposed studs (not shown) which engage a groove (not shown) formed on the wheel spindle 22. It will be readily apparent from the foregoing disclosure that rotation of the wheel spindle 22 will be imparted through the worm I25, the worm gear I25, the shaft I21, the eccentric stud I28, the eccentric disc I29 to oscillate the connecting rod I39 which serves to impart an oscillating movement to the yoked member I33 thereby reciprocating the wheel spindle 22 axially within its bearings. A pipe I55 connects the control valve I60 with a cylinder I56. The cylinder I56 contains a slidably mounted piston I51 which is arranged automatically to stop and to start wheel spindle reciprocation before and after a grinding wheel truing operation. A pipe I58 connects the control valve I66 with other mechanisms of the machine (not shown).

The mechanism as above described includes a stop plate 53 having a plurality of stop pins or studs 54 for limiting the approaching movement of the grinding wheel 23 so as to compensate for the swivelling movement of the swivel table I4. This compensation may also be obtained as illustrated diagrammatically in the modification shown in Figs. 18 and 19. In the latter figures, the diameter of the master cams 39 may be stepped or graduated, that is, of different diameters to compensate for the swivelling of the swivel table I 4 so that the cams on the camshaft 35 to be ground will be ground to the same diameter. In utilizing this modified construction as diagrammatically illustrated in Figs. 18 and 19, the wheel slide I6 is fed into a predetermined forward approaching position before the wheel 23 is moved into operative engagement to grind each successive cam on the camshaft 35.

The grinding wheel 23 is formed with a true cylindrical operative face. The wheel may be maintained in true cylindrical form by means of a suitable truing apparatus such as for example, a wheel guard truing mechanism mounted on top of the wheel guard or the wheel slide or a truing tool adjustably fixed on the longitudinally movable worktable II, in which case the truing tool is traversed in a direction parallel to the grinding wheel axis. With such an arrangement the grinding wheel may be readily trued regardless of the position of the swivel table. If desired a table type truing apparatus may be provided such as a truing tool I40 which is mounted on the rock bar 30. This truing apparatus may be substantially the same as that shown in the prior U. S. patent to Crompton above referred to. In utilizing this type of truing mechanism, the swivel table must be swivelled to a central position for the truing operation. In order to locate the swivel table I4 in position for truing, a hydraulically operated mechanism may be provided comprising a cylinder I45 (Fig. '1) which contains a slidably mounted piston I46. The piston I46 is provided with an integral piston rod I41 which carries a stop block I48. The stop block I48 is arranged so that it may be moved into the path of the lug I I6 on the table I I and a stop screw I49 carried by the lug II9 on the end of the swivel table. When fluid under pressure is passed through a pipe I58 into a cylinder chamber II, the piston I46 is moved toward the right (Fig. '1) to move the stop block I48 into an operative position. During this movement, fluid within a cylinder chamber I52 may exhaust through a pipe I53 and through a valve I54. The valve I54 is provided in case it is desired to render the cylinder I45 and the piston I46 inoperative. In the latter case when the piston I46 is in a left-hand end position (Fig. '1), the cylinder chamber I52 is filled with fluid, the valve I54 may be closed thereby lockingthe fluid within the cylinder chamber I52 and holding the piston I46 and the stop block I48 in an inoperative or left-hand end position. The operation of the cylinder I45 is automatic and ties in with the automatic control system to be hereinafter described.

A suitable hydraulic control mechanism is provided for controlling the admission to and exhaust of fluid from the cylinders 98 and I45. This control mechanism may comprise a solenoid actuated valve I66 which is actuated by means of a solenoid SI, a control valve I6I which is actuated by a solenoid S4 and a control valve I62 which is actuated by the solenoids S2 and S3. The control valve I60 serves to control the admission of fluid to the cylinder chamber I5I in the cylinder I45 for moving the stop block I48 into an operative position. The control valve I62 serves in one position to admit fluid under pres sure to the control valve I6I and in the other position to admit fluid through the pipe I69 into the cylinder chamber I08 to move the piston 99 upwardly (Figs. 7 and 16) to swivel the swivel table I4 in a clockwise direction. The control valve I6I, in the position illustrated in Fig. 16, serves to pass fluid under pressure through the pipe I06 into the cylinder chamber III! to move the piston 69 downwardly thereby rocking the swivel table I4 in a counter-clockwise direction into the position illustrated in Fig. 16. In the reverse position of the valve I6I, fluid is passed through the pipe I53 into the cylinder chamber I52 to move the piston I46 toward the left (Figs. 7 and 16) to withdraw the stop block I48 to an inoperative position. As above explained if desired the stop block I48 may be locked in an inoperative position by closing the valve I54 when the piston I46 is in a left-hand end position (Figs. 7 and 16).

As shown in Fig. 16 the machine is set up for grinding alternate adjacent pairs of cams on the camshaft 35 tapering in th opposite directions as shown in Figs. 14 and 15. A pipe I64 serves to supply fluid under pressure to the solenoid actuated valve I68. The valve I 68 comprises a slidably mounted valve member I63 which is normally held in a right-hand end position by means of a compression spring I66. When the solenoid SI is energized, the valve member I63 is shifted toward the left. When the solenoid SI is energized, fluid under pressure from the pipe I64 may pass through a valve chamber I65, through the pipe I56 into the cylinder chamber I5I to move the piston I46 toward the right into the position illustrated in Fig. '7 thus moving the stop block I48 into an operative position.

The fluid actuated control valve I6I is a pressure actuated valve comprising a slidably mounted valve member I68 the movement of which is controlled by a pilot valve I69. The pilot valve I69 comprises a slidably mounted valve member I10 which is normally held in a right-hand end position by means of a compression spring Ill. The solenoid S4 when energized serves to shift the valve member I 68 into a right-hand end position. In the position as illustrated in Fig. I6, fluid under pressure passing through the pipe I64 passes through a passage I13 into an end chamber I14 .to move the valve member I68 into an extreme left-hand end position as shown in Fig. 16. During this movement fluid within an end chamber I15 may exhaust through a passage I16, through a central passage I11 in the pilot valve member I10 and exhaust through a pipe I18.

In the position of th valve member I68 (Fig. 16) fluid under pressure passing through the pipe I86 passes through a valve chamber. I81

9 and through the pipe I86 into the cylinder chamber I81 to cause a downward movement of the piston 99, thereby rocking the swivel table in a counter-clockwise direction into the position illustrated in Fig. 16. When the valve member I68 is shifted into a reverse position, that is, its extreme righthand end position, fluid under pressure passing through the pipe I86 passes through the valve chamber I81 and through the pipe I53 into the cylinder chamber I52 to move the piston I46 toward the left (Figs. 7 and 16) thereby moving the stop block I48 to an inoperative position.

The control valve I62 comprises a slidably mounted valve member I80 which is controlled by a slidably mounted pilot valve member I8I. The pilot valve member is shown in an extreme left-hand end position and is arranged to be actuated by means of the solenoids S3 and S2.

In the position of the valve I92 (Fig. 16) fluid under pressure from the pipe I64 passes through a chamber in the pilot valve member I8 I, through a passage I82 into an endchamber I83 to move the valve member I89 into a right-hand end position as illustrated in Fig. 16. During this movement of the valve member I89 fluid within an end chamber I84 may exhaust through a passage I85 and out through an exhaust pipe I18. When the valve member I80 is in a right-hand end position fluid under pressure in the pipe I64 passes through a valve chamber I88! and through the pipe I86 to admit fluid to the valve chamber I8? in the central valve I6 I.

When the solenoid S2 is energized, the pilot valve member I8I is shifted toward the right so that fluid under pressure from the pipe I68 passes through the passage I85 to shift the valve member I88 toward the left so that fluid under pressure from the pipe I64 passes through the valve chamber I86a and through the pipe I09 into the cylinder chamber 588 to cause an upward movement of the piston 99 thereby imparting a clockwise swivelling movement to the swivel table I4.

To facilitate automatically controlling the valves I60, IEiI and I62, a plurality of limit switches actuated by adjustable dogs on the front edge of the table are provided; .An adjustable table dog I98 is provided for actuating a vertically movable plunger I9I against the compression of a spring I92. A downward movement of the plunger I9I caused by dog I99 serves to close the normally open limit switches LS9 and LSIIl. A normally open limit switch I95 is arranged to be actuated by a pair of adjustable dogs I96 and I9! when the table is moved toward the right. A normally open limit switch I98 is arranged to be closed by an adjustable dog I99 when the table II is moved toward the right. Similarly a normally open limit switch 208 is arranged to be actuated by an adjustable table dog I when the table II is moved toward the right. In the operation of the arrangement shown in Fig. 16, the swivel table I4 is swivelled after each pair of cams have been ground so that surfaces tapering in the opposite direction are produced on adjacent pairs of cams. The table dogs I96, I91, I99 and 20I'are arranged so that during the movement of the table II toward the left, the dogs ride idly over the respective limit switches. 'As shown in Fig. 16, the table is shown in a start position, that is, with the table in a left-hand end position. When a grinding cycle is started, the table II indexes toward the right to position cam No. I on the camshaft in an operative position relative to the grinding wheel 23. After the first two cams on the right-hand end of the camshaft have been ground and the table starts the next indexing movement toward the right, the dog I91 engages and closes the limit switch I95 to energize the solenoid S2 thereby shifting the pilot valve member I8I toward the right so that fluid under pressure from the pipe I84 passes through the passage I into the end chamber I84 to shift the valve member I88 toward the left. In this position of the valve member I80, fluid under pressure passing through the pipe I64 passes through the valve chamber I86a and through the pipe I99 into the cylinder chamber I88 to move the piston 99 upwardly (Fig. 16) to swing the swivel table I4 in a clockwise direction to position the camshaft 35 for grinding cams No. 3 and No. 4 so that the surfaces will taper toward the left. After the third and fourth cams have been ground and the table starts its indexing movement toward the right, the dog I99 engages and closes the limit switch I98 which serves to energize the solenoid S3 to shift the pilot valve member I8I toward the left into the position illustrated in Fig. 16. In this position of the pilot valve member I8I, fluid under pressure from the pipe I64 passes through the passage I82 into the end chamber I83 to shift the valve member I88 toward the right so that fluid under pressure passing through the pipe I64 may pass through the pipe I86 into the valve chamber I81 of the valve NH and through the pipe I08 into the cylinder chamber I09 to cause a downward movement of the piston 99 (Fig. 16) to again swivel the swivel table-I4 in a counter-clockwise direction to position the camshaft 35 for grinding cams No. 5 and No. 6 on the camshaft 35 with surfaces tapering toward the right.

During the next indexing movement of the table toward the right, the dog I96 engages and closes the limit switch I so as to again energize the solenoid S2 thereby shifting the valve member I88 toward the left and in a manner above described causing fluid under pressure to pass into the cylinder chamber I08 to cause an upward movement of the piston 99 thereby swivelling the swivel table I4 in a clockwise direction to position the camshaft 35 in position for grinding cams No. I and No. 8 on the camshaft 35 with surfaces tapering toward the left.

After the cam No. 8 has been ground, the table moves through an idle stroke toward the left. As the grinding wheel 23 approaches the truing tool I40, the dog I98 engages and depresses the plunger I9I to close the limit switches LS9 and LSI 8. The closing of the limit switch LS9 serves to energize the solenoid SI to shift the valve member I63 so that fluid under pressure from the pipe I64 passes through a chamber in the valve member I63, through the pipe I58 into the cylinder chamber I5I to cause the piston I46 to move toward the right (Figs/'7 and 16) to position the stop block I48 in an operative position between the lug H6 and stop screw I49. At the same time the closing of the limit switch LSI8 energizes the solenoid S3 to shift the valve member I88 into a right-hand end position (Fig. 16) so that fluid under pressure will be passed through the pipe I88 into the valve chamber I81 of the valve I6I and through the pipe I86 into the cylinder chamber I81 to cause a downward movement of the piston 99 to swivel the swivel table I4 in a counter-clockwise direction. The swivelling movement of the table in a counterclockwise direction continues until the stop screw aceas'ee I49 engages the stop block I48 thereby locating the swivel table in a central position for a grinding wheel truing operation. Continued movement of the table II toward the left passes the truing tool I40 across the face of the grinding wheel. During this movement, the dog 20I rides idly over the limit switch 200. After the truing tool has completed one pass across the grinding wheel 23, the table II is automatically reversed and starts its movement in the reverse direction to again traverse the truing tool I40 across the operative face of the grinding wheel. After the second pass of the truing tool I40 across the face of the wheel 23, the dog 20I momentarily closes the limit switch 200 to momentarily energize the solenoid S4 which shifts the pilot valve I toward the left (Fig. 16) to pass fluid through the passage I'Ifi into the end chamber I to shift the valve member I68 toward the right so that fluid under pressure passing through the pipe I86 passes through the valve chamber I8? and through the pipe I53 into the cylinder chamber I52 to move the piston I40 toward the left thereby withdrawing the stop block M8 to an inoperative position.

The valve member I58 remains in the righthand end position only momentarily. As soon as the solenoid S4 is deenergized, the released compression of the spring I'II shifts the valve member I10 into the position illustrated in Fig. 16 to shift the Valve member I63 into its lefthand end position (Fig. 16) so that fluid under pressure in the pipe I86 passes through the chamber I81, through the pipe I05 into the cylinder chamber IN to continue the downward movement of the piston 99 thereby completing the swivelling movement of the swivel table I4 in a counter-clockwise directionso that the swivel table I4 is positioned correctly for'grinding cams Nos. I and 2 on the next camshaft 35. The traversing movement of the table II stops at the end of the cycle in the position as illustrated in Fig. 16. The ground camshaft 35 may then be removed from the machine and a new camshaft inserted therein after which the cycle of operation can again be carried out in a manner above described. 7

The operation of the positioning and feeding movements is coordinated as follows: fluid under pressure is passed through a pipe 205, through a throttle valve 206, into a cylinder chamber 201 to cause the piston 46 to move toward the left (Figs. 5 and 17) to cause a rapid approaching movement of the slide I5. During th rapid approaching movement of the slide, fluid within a cylinder chamber 208 may exhaust through a pipe 209, through a control valve 2) and exhaust through a pipe 2II. At the same time fluid under pressure passes through the pipe 205, it passes also through a throttle valve 2I2 into a cylinder chamber 2I3 to cause the piston TI to move toward the right thereby imparting a rotary motion through the gear 14 to rotate the feed screw I0 to impart a feeding movement to the wheel slide base I9 and the grinding wheel slide I6. This latter feeding movement serves as a grinding feed to advance the grinding wheel 23 into the cam being ground during the grinding operation. During the infeeding movement caused by the piston 'I'I, fluid within a cylinder chamber 2I4 to cause a rapid movement of the piston 'Il toward the left thereby returning the wheel slide base I9 'to its initial position. At the same time fluid under pressure also passes through a check valve 2I8 into the cylinder chamber 208 to cause a rapid movement of the piston 45 toward the right to return the wheel slide IE to a rearward or inoperative position. It will be readily apparent from the foregoing disclosure that the throttle valves 205, M0, 2I2, and H6 serve to control the speed of movement of the pistons 40 and TI.

The operation of this improved cam grinding apparatus will be readily apparent from the foregoing disclosure. Assume the valve I 54 to be closed to lock the piston I46 in a left-hand end position (Fig. 16) that is with the stop block I48 in an inoperative position. The swivel table I4 is swivelled in a counter-clockwise direction to position the cams No. I and No. 2 on the shaft 35 in position relative to the grinding wheel 23. The table is successively indexed longitudinally toward the right to first grind No. I and then No. 2 cam. When the table indexes for the No. 3 cam, the dog I9! actuates the limit switch I95 to energize the solenoid S2 thereby shifting the valve member I in the control valve I62 into a left-hand end position so that fluid under pressure is passed through the pipe I09 into the cylinder chamber I08 to move the piston 99- upwardly (Fig. 16) thereby swinging the swivel table I4 in a clockwise direction to position cams No. 3 and No. 4 in proper position relative to the grinding wheel 23 so that the grinding wheel 23 has an opposite taper thereon. When the table is indexed to position cam No. 5 in operative relation with the grinding wheel 23, the table dog I99 actuates the limit switch I to energize the solenoid S3 thereby shifting the valve member I80 of the control valve I02 into the position 11- lustrated in Fig. 16 so that fluid under pressure passing through the pipe I 64 enters the valve chamber I86a, passes through the pipe I80 into the valve chamber I81 in the control valve IBI and through the pipe I06 into the cylinder chamber I01 so as to cause a downward movement of the piston 99 to swing the swivel table I4 in a counter-clockwise direction into the position illustrated in Fig. 16 to position cams No. 5 and No. 6 relative to the grinding wheel 23 so that the peripheral surfaces thereof taper in a direction toward the right. When the table indexes to position cam No. I in operative relation with the grinding wheel 23, the dog I96 again actuates the limit switch I to energize the solenoid S2 thereby shifting the valve member I80 in the control valve I62 into a left-hand end position so that fluid under pressure causes an upward movement of the piston 99 to swing the swivel table I4 in a clockwise direction so that the cams Nos. I and. 8 will be ground with a peripheral surface tapering toward the left. After cam No. 8 has been ground, the table I I traverses through an idle stroke toward the left and'returns to its initial position.

If a truing operation is desired after a camshaft has been ground, a truing operation'may be initiated when the table reaches or approaches its left-hand end position. If a wheel guard truing device is employed then the grinding wheel may be trued at any time during the cycle and if desired the truing operation may be performed automatically. If desired the truing. tool I40 may be fixedly mounted on the table II, in which condition the grinding wheel may be'automatitherein specified of essary to return the swivel table to a central position unless desired.

The apparatus as illustrated in the drawings is set up so that alternate pairs of cams on a camshaft will be ground with peripheral surfaces tapering in opposite directions and a camshaft having eight cams thereon has been illustrated. If desired the apparatus may be set up so that alternate cams will be ground tapering in opposite directions by adding additional table dogs for controlling the limit switches I95 and I98. If desired all of the cams on one end of the camshaft may be ground tapering in one direction while the cams on the other end of the camshaft may be ground tapering in the opposite direction by rearrangement of the dogs on the table ll.

It will thus be seen that there has been provided by this invention apparatus in which the 'various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiments above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a cam grinding machinehaving a base, a transversely movable wheel head, a rotatable grinding wheel thereon, means to feed said head transversely, a longitudinally movable table, a swivel table thereon, a rotatable camshaft support thereon, means including a motor for intermittently indexing the table longitudinally successively to position a plurality of spaced cams to be ground in operative relation to the grinding wheel, means including. an independent motor to swivel said swivel table in either direction, adjustable stops to limit the swivelling movement of the table in either direction, and means actuated by and in timed relation with the longitudinal table movement to control the swivelling means so as to alternately swivel said table in opposite directions after each pair of cams has been grounds to facilitate grinding a predetermined taper in opposite directions on alternate pairs of cams to be ground. I

2. In a grinding machine, as claimed in claim 1, in combination with the parts and features therein specified of means to compensate for the swivelling of the swivel table including an indexable member having a plurality of spaced adjustable stops successively to limit the approaching movement of the wheel slide, and means including adjustable dogs on said table to index said member to shift the stop corresponding to the cam being ground into an operative position.

3. In a grinding machine, as claimed in claim 1, in combination with the parts and features means for automatically varying the operative position of the wheel head so as to compensate for the swivelling of the swivel table including a rotatable indexable plate, a plurality of spaced stops on said plate to correspond with the spaced portions on the workpiece to be ground, means including a star wheel to retate said plate, and means including a plurality of adjustable dogs on said table intermittently to actuate said star wheel to index said plate automatically to position the stop corresponding to the cam being ground into an operative position to determine the forward operative position of the wheel head.

4. In a cam grinding machine having a base, a transversely movable wheel head, a rotatable grinding wheel thereon, means to feed said head transversely, a longitudinally movable worktable, a swivel table thereon having a rotatable camshaft support thereon, means including a motor for intermittently indexing the table longitudinally successively to position a plurality of spaced cams to be ground in operative relation with the grinding wheel, means including an independent motor to swivel said swivel table in either direction, adjustable stops to limit the swivelling movement of the swivel table in either direction, and means automatically actuated by and in timed relation with the longitudinal movement of the table to control the swivel means so as to swivel the swivel table in one direction to facilitate grinding a predetermined taper in one direction on a portion of the cams to be ground and to swivel said swivel table in the opposite direction to facilitate grinding a, predetermined taper in the opposite direction on the remainder of the cams to be ground.

5. In a grinding machine having a base, a transversely movable wheel head having a rotatable grinding wheel thereon, a longitudinally movable table, a swivel table thereon having a rotatable work support thereon, means for moving the table longitudinally to position a Workpiece relative to the grinding wheel, means to swivel said swivel table in either direction to facilitate grinding tapers in opposite directions on spaced portions of the workpiece, means including an index pawl to facilitate locating the swivel table in a central position for a truing operation, and means actuated by and in timed relation with the longitudinal movement of the table to control the movement of said pawl.

6. In a grinding machine having a transversely 'movable Wheel head, a rotatable grinding wheel table movement to control the swivel motor so as to swivel said swivel table in one direction to facilitate grinding a predetermined taper in one direction on part of the portions to be ground, and to swivel said swivel table'in the opposite direction to facilitate grinding a predetermined taper in the opposite direction on the remainder of the portions to be ground,

'7. In a cam grinding machine having a base, a

transversely movable wheel head, a rotatable grinding wheel thereon, means to feed said head transversely, a longitudinally movable table, a swivel table thereon having a rotatable camshaft support, means for moving the table longitudinally successively to position spaced cams in operative relation to the grindingwheel, a piston and cylinder to swivel said swivel table in either direction, adjustable stops to limit the swivelling movement of the swivel table in either direction, and means including a control valve mechanism actuated by and in tiined relation with the table movement to control the piston and cylinder so as to alternately swivel said swivel table in opposite directions after each cam has been ground to facilitate grinding a predetermined taper in opposite directions on alternate cams to be ground.

8. In a cam grinding machine having a base, a transversely movable wheel head, a rotatable grinding wheel thereon, a means to feed said head transversely, a longitudinally movable table, a

swivel table thereon having a rotatable camshaft support, means for moving the table longitudinally successively to position spaced cams in operative relation to the grinding wheel, a piston and cylinder to swivel said swivel table in either direction, adjustable stops to limit the swivelling movement of the swivel table in either direction, and means including a control valve mechanism actuated by and in timed relation with the table movement to control the piston and cylinder so as to alternately swivel said swivel table in opposite directions after each pair of cams has been ground to facilitate grinding a predetermined taper in opposite directions on alternate pairs of cams to be ground.

9. In a cam grinding machine having a base, a transversely movable wheel head, a rotatable grinding wheel thereon, means to feed said head transversely, a longitudinally movable worktable, a swivel table thereon having a rotatable camshaft support thereon, means for moving the 2 table longitudinally successively to position successive cams in operative relation with the grinding wheel, a fluid motor to swivel said swivel table in either direction, adjustable stops to limit the swivelling movement of the swivel table in either direction, and means including a control valve mechanism automatically actuated by and in timed relation with the longitudinal movement of the table to control the swivel motor so as to swivel the swivel table in one direction to facilitate grinding a predetermined taper .in one direction on a portion of the cams to be ground and to swivel said swivel table in the opposite direction to facilitate grinding a predetermined taper in the opposite direction on the remainder of the and means including a piston and cylinder actu ated by and in timed relation with the longitudinal movement of the table to control the movement of said pawl.

11. In a grinding machine having a base, a transversely movable wheel head, .a rotatable grinding wheel thereon, means to feed said head transversely, a longitudinally movable worktable. a swivel table thereon having a rotatable work support thereon, means for moving the table longitudinally successively to position spaced portions on a workpiece relative to the grinding wheel, a fluid motor to swivel said swivel table in either direction, adjustable stops to limit the swivelling movement of the swivel table in either direction, means including a solenoid-actuated control valve for controlling said swivel motor, a plurality of table dogs adjustably mounted on said table, and means including a switch actuated thereby for controlling said valve automatically to swivel .said swivel table in timed relation with the table movement.

12. In a grinding machine having a base, a transversely movable wheel head, a rotatable grinding wheel thereon, means to feed said head transversely, a longitudinally movable worktable, a swivel table thereon having a rotatable work support thereon, means for moving the table longitudinally successively to position spaced por tions on a workpiece relative to the grinding wheel, a fluid motor to swivel said swivel table in either direction for a taper grinding operation, adjustable stops to limit the swivelling movement of the swivel table in either direction, means including a solenoid-actuated control valve for controlling the fluid motor, means including an index pawl to facilitate locating the swivel table in a central position for a truing operation, a fluid motor to actuate said pawl, means including a solenoid-actuated control valve therefor, a plurality of adjustable dogs on said table, and a plurality of limit switches actuated by said dogs to actuate the control valves in timed relation with the longitudinal movement of said table.

13. In a cam grinding machine having a base, a transversely movable wheel head, a rotatable grinding wheel thereon, means to feed said head transversely, a longitudinally movable table on said base, a swivel table thereon, a rock bar pivotally supported on said swivel table, a rotatable camshaft support on said rock bar, means including a plurality of master cams and a follower roller in engagement therewith interposed between the rotatable work support and the table to impart a rocking movement to said bar to facilitate grinding predetermined contours on a plurality of spaced cams on a cam shaft to be ground, means including a motor for indexing said table longitudinally successively to position a plurality of spaced cams to be ground in operative position relative to the grinding wheel, and means including an indepedent motor to swivel said swivel table in either direction, adjustable stops to limit the swivelling movement of the table in either direction and means actuated by and in timed relation with the longitudinal movement of the table to control the swiveling motor so as to alternately swivel said table in opposite directions after each pair of cams has been ground to facilitate grinding a predetermined taper in opposite directions on alternate pairs of cams tobe ground.

CLARENCE J. GREEN.

References Cited in the file of'this patent UNITED STATES PATENTS Number Name Date 1,693,723 Mitchell Dec. 4, 1928 1,845,172 Morey et al. Feb. 16, 1932 1,970,000 Dunbar et a1 Aug. 14, 1934 2,041,244 Green May 19, 1936 2,244,643 Flygare June 3,1941 2,356,394 Garside Aug. 22, 1944

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