US2556811A - Cam grinding machine - Google Patents

Description

June 12, 1951 R. P. HOOK 2,556,811

CAM GRINDING MACHINE Filed May 18, i950 r 3 Sheets-Sheet 1 .June12,1951 R RHO K 2,556,811

CAM GRINDING MACHINE Filed May 18, 1950 z sneak-sheet 2 filuezgcor R115 SELL I? HOOK June 12, 1951 R. P. HOOK CAM GRINDING MACHINE 3 Sheets-Sheet 5 Filed May 18, 1950 pzvewvor RUSSELL F2 HOOK Patented June 12, 1951 UNITED STATES FATENT @FFIQE Russell P, Hook, Worcester, Mass, assignor to Norton Company, Worcester, Mass, a corporation of Massachusetts Application May 18, 1950, Serial No. 162,729

. 4 Claims.

1 The invention relates to grinding machines, and more particularly to an improvement in cam grinding apparatus.

One object of the invention is to provide a simple and thoroughly practical cam grinding machine. Another object is to provide an automatic mechanism for separating the cam being ground from the grinding wheel when the nose or high point of the cam is in contact therewith. Another object is to provide an automatic nose lifting device which serves automatically to separate the cam being ground from the grinding wheel when a predetermined portion of the cam, such as the nose or high point of the cam, is in contact with the wheel. Another object is to provide an electrically controlled mechanism for automatically separating the cam being ground from the grinding wheel when the cam is in a predetermined position with respect to the grinding Wheel. solenoid-controlled spring-actuated wedge for automatically separating the cam being ground andv the grinding wheel when nose of the cam is in operative engagement with the grinding wheel. in part pointed out hereinafter.

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 will be indicated in the following claims.

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

Fig. l is a fragmentary plan view of a cam grinding machine embodying the invention, having a portion of the workhead cover broken away to show details of construction;

Fig. 2 is a cross-sectional view, taken approximately on the line 2-2 of Fig. '1;

Fig. 3 is a fragmentary view of the rock bar and associated parts together with the driving mechanism therefor;

Fig. 4 is a fragmentary plan view, on an enlarged scale, of the solenoid-actuated wedge mechanism for separating the master cam and the follower roller;

Fig. 5 is a fragmentary vertical sectional View, on an enlarged scale, through the master cam and the follower roller spindle and shaft respctively;

Fig. 6 is a fragmentary horizontal sectional view, on an enlarged scale, through the rock bar actuating: mechanism; and

A further object is to provide a Other objects will be in part obvious or Fig. 7 is a combined hydraulic and electrical diagram showing the rock bar actuating cylinder and control valve therefor, together with the electrically controlled nose lifting device.

A cam grinding machine has been illustrated in the drawings having a base It which supports a longitudinally movable work supporting table i l. The table l i is arranged to slide longitudinally relative to the base 50 on a V-way l2 and a flatway 83 formed on the upper surface of the base It. The table II serves as a support for a rock bar l5 having trunnicns I6 formed at the opposite ends thereof which are rotatably supported in bearings (not shown) fixedly supported on the upper eurface of the table II.

A transversely movable wheel slide of the conventional type is arranged to slide transversely on the base it on a V-way and a flatway (not shown) formed on the upper surface of the base It. The wheel slide 2% serves as a support for a rotatable wheel spindle 2! having a grinding wheel 22 mounted on the left-hand endthereof.

A master cam spindle 25 (Fig. 3) is rotatably supported in bearings 26 and 21 which are fixedly mounted on the rock bar 15. The master cam spindle 25 serves as a support for a plurality of master cams 28. The right-hand end of the master cam spindle 25 is provided with a work center 29 which is arranged to support the left-hand end of a camshaft 30 to be ground. A driving dog 3| is provided on the left-hand end of the camshaft to be ground by means of which the camshaft 30 may be rotated in timed relationship with the master cam spindle 25.

The master cam spindle and associated parts .are contained within a workhead housing 32 which is mounted on the left-hand end of the table H. An electric motor 33 mounted on top of the housing 32 is provided with a motor shaft 34 which carries a multiple V-groove pulley 35. The pulley 35 is connected by multiple V-belts 36 with a multiple V-groove pulley 37. The pulley 37 is rotatably supported on anti-friction bearings 38 and 39 which are in turn supported by a non-rotatable shaft 48 which is fixedly mounted Within the workhead housing 32. A multiple v-groove pulley 4| is formed integral with the multiple V-groove pulley 31 and is connected by multiple V-belts 42 with a multiple V-groove pulley 43. The pulley 43 is journalled on antifriction bearings 44 which are carried by a sleeve 45 which is fixedly mounted within the workhead housing 32. The pulley 43 is connected by means of a universal joint 46 with a drive shaft 41. The drive shaft 4? is connected by means of a universal joint 38 with the left-hand end of the master cam spindle 25 (Fig. 3). It will be readily apparent from the foregoing disclosure that rotation of the motor shaft 34 will be transmitted through the mechanism above de scribed to impart a rotary motion to the master cam spindle 25, the master cams 28, and also the camshaft 36 to be ground.

A master cam follower roller is slidably keyed on a rotatable shaft 51 which is journalled within the workhead housing 32 in fixed relationship with the work table I I. A suitable follower roller indexing mechanism 52 is provided for indexing the master cam roller 5% longitudinally relative to the shaft 5| in timed relationship with the indexing movements of the table II automatically to locate the master cam roller 5i! opposite a predetermined master cam 28 which corresponds with the cam to be ground. This indexing mechanism is not considered a part of the present invention and consequently has not been illustrated in detail. Ihis mechanism may be substantially identical with that shown in the expired U. S. Patent No. 1,783,?55 to C. G. Trefethen and A. G. Belden dated December 2, 1930, to which reference may be had for details of disclosure not contained herein.

A suitable mechanism is provided for moving the rock bar IE to and from an operative position and to maintain a suitable pressure on the rock bar to maintain the master cam 28 in operative engagement with the follower roller 58. This mechanism may com-prise a cylinder 69 and a piston 5i which is operatively connected to rock the rock bar to and from an operative position. It is desirable to rock the bar i5 to an inoperative position so as to separate the master cam 28 from the follower roller 5i before the table ii is indexed longitudinally. The piston 6i is connected to one end of a piston rod 62. A U-shape frame 83 is clamped in a fixed position on the piston rod 62 by means of nuts Bil (Fig. 6). An upwardly extending actuating arm 55 is fixedly mounted on the rock bar l5 by means of screws 86 and 51. ihe upper end of the arm 55 is provided with a pair of horizontally extending arms 58 and S9. A pair of tension springs H3 and H are connected by screws F2 and 73 to the arms 63 and 69 respectively of the arm 65. The other ends of the springs iii and H are connected to the oppositely projected arms 53a and 63b respectively of the U-shape frame 63. By adjust ing the screws 12 and 73, the tension of the springs 76 and H may be varied as desired. The arms 68 and 69 of the arm 65 are provided with rollers Hi and i5 respectively which are arranged .to be engaged by the U-shape frame 63 when the piston is moved toward the right to shift the rock bar to an inoperative position.

When fluid under pressure is admitted through a port 79 into a. cylinder chamber 78 to move the piston toward the right, the U-shape frame 63 will be moved into engagement with the rollers 14 and 15, after which continued movement of the piston 6| toward the right will swing the arm .GS-in a clockwise direction (Figs. 2 and 5) to impart a clockwise movement to the rock bar so as to separate the master cam 22 from the follower .roller 5!] and also to separate the cam being ground from the grinding wheel 22. During this movement of the piston 6|, fluid is exhausted from a cylinder chamber ll through a port '53. The screws l2 and '13 are preferably adjusted so that when the piston 6! is in its extreme left- 4 hand end position, the U-shape frame will be separated from the rollers '14 and "i5 and the tensicn of the springs '59 and ll will be sufficient to maintain the master cam 28 in operative engagement with the periphery of the follower roller 5:; during rotation of the master cam spindle 25 so as to impart a controlled oscillating movement to the rock bar l5 during a grinding operation.

When the piston 61 moves toward the right, to shift the rocl: bar to an inoperative position, the U-shape frame 63 moves toward the right and due to the clearance between the frame 53 and the rollers i l and i5 relieves the tension of the springs 7i] and 'il respectively. When the piston ti and the frame 63 have moved a sufficient distance toward the right, the frame 53 engages the rollers i i and i5 and rocks the arm 65 and the rock bar H5 in a clockwise direction (Figs. 2 and 5) into an inoperative position.

Similarly when fluid under pressure is admitted through the port into the cylinder chamber if to move the piston 8i toward the left, the tension of the springs 70 and H serves to maintain the rollers 74 and 15 in operative engagement with the U-shape frame 63 until the master cam 28 moves into operative engagement with the follower roller 50. Continued movement of the piston 65 toward the left causes the U- shape frame 63 to separate from the rollers 14 and i5 and to increase the tension of the springs iii and H to the desired operating tension for maintaining the master cam 28 in operative engagement with the follower roller 5!] with the desired pressure during a grinding operation. By utilizing this construction, the extending and contracting of the springs id and II are reduced to a minimum.

A control valve is provided for controlling the admission to and exhaust of fluid from the cylinder 59. The control valve 85 is preferably a piston-type valve comprising a valve stem 86 having a plurality of spaced valve pistons 81, 8B and 89 formed integrally therewith. Fluid under pressure from any suitable source of supply is conveyed through a pipe 99 into a valve chamber 9| located between the valve pistons 88 and 89. In the position of the valve (Fig. 7) fluid entering the valve chamber 9| passes through a pipe 92 into the cylinder chamber 7'! to cause the piston 6| to move into a left-hand end position. During movement of the piston 6| toward the left, fluid within the cylinder chamber 78 exhausts through a pipe 93 into a valve chamber 94 located between the valve pistons 81 and 88 and passes out through a passage 95 and a pipe 96 into the fluid reservoir (not shown). A compression spring 91- surrounding the valve stem 86 serves normally to hold the valve stem 86 in a right-hand end position. An electric solenoid 88 is provided when, when energized, serves to shift the valve stem 86 into a left-hand end position.

It is desirable to provide an automatic control for the solenoid 98 so that after the cam being round has rotated a predetermined number of rotations in operative engagement with the grinding wheel, the solenoid 98 will be deenergized to cause fluid under pressure to pass into the cylinder chamber 18 to move the piston 6| toward the right thereby rocking the rock bar [5 in a clockwise direction to an inoperative position. In order to facilitate automatic control of the valve 85, an electric counter I00 is provided.

This electric counter l 00 may be one of the comas shown a Microfiex electric counter such as manufactured by the Signal Electric Corporation'of Moline, Illinois. Electric power is suppliedfrom any suitable source such as indicated by the power lines IUI. The rock bar I5 is provided with an arm I02 (Figs. 2, 5 and 7) which is arranged to rock in the path of an actuating roller I03 which is mounted on the actuating arm I04 of a normally closed limit switch I05. The arm I02 is preferably arranged so that during' the normal oscillation of the rock bar during each rotation of the master cam 28, the limit switch I05 will be opened to impart an impulse to thecounter )0. After a predetermined number of impulses on the counter, a circuit is broken to deenergize the solenoid 98 thereby rel-easing the compression of the spring 91 which moves the valve stem 86 toward the right into a righ hand end position. When the valve stem is in the right-hand end position fluid under pressure in the pipe line 99 passes through the valve chamber 94, through the pipe 93 into the cylinder chamber I8 to move the piston 6i toward the right (Fig. 7) thereby rocking the arm 65 and the rock bar 15 in a clockwise direction to separate the master cam 28 from the follower roller 5E! and at the same time to separate the cam being ground from the grinding wheel 22.

It has been found desirable in the grinding of caries to separate the cam being ground from the grinding wheel when the nose or high point of the cam is in contact with the grinding wheel thereby eliminating slight reentrant curve on the surface of the cam being ground when the cam and grinding wheel separate. This is preferably accomplished by means of an automatically controlled mechanism comprising a follower, such as a slidably mounted plunger IE6 having a tapered end portion Iili. The slidably mounted plunger I06 is supported in a bracket H2 mounted within the upper portion of the workhead housing 32. A compression spring IE8 is provided which is arranged normally to tend to move the plunger I06 toward the right. A solenoid I09 is provided which, when energized, serves to movethe plunger [05 toward the left into an inoperative position as illustrated in Fig. '6. The tapered face ID! of the plunger i 06 is arranged to engage cam faces I I!) and HI fixedly mounted on the upper end of the arm 65. When the solenoid I09 is deenergized, the release compression of the spring m8 serves to move the plunger I05 toward the right so that the tapered portion l! thereof moves into the full line position Ifi'la (Fig. 4) into engagement with the cam face III).

to rock the rock bar so as to separate the master cam '28 from the roller E! but serves to hold the arm 65 as the master cam rotates so that when the high point of the master cam is in engagement with the grinding wheel, the taper I01 will be moved into engagement with the cam face III, as shown in Fig. 1. The taper I0! holds the ca'm'III' in this position and does not allow the arm 65 to rock in a counter-clockwise direction after the high point has been passed.

In order that the plunger I66 may be operated on the last rotation of the cam being ground, the solenoid N39 is preferably connected so as to be actuated by the electric counter I013. The electric counter I08 is preferably adjusted so that is receives the last impulse when the high point of the cam being ground approaches contact with the grinding wheel. As the counter I00 counts out, it serves to break a circuit there- The compression of the spring IE8 is not strong enough by deenergizingthe solenoid I09 so as to allow the tapered end m1 of the plunger I06 to move under the influence of the spring I08 into opera-'- tive engagement with the cam faces H0 or III so that the arm 65 will be locked when it reaches its extreme throw in a clockwise direction when the high point of the master cam is in engagement with the follower roller 50. At the same time the solenoid N39 is deenergized, the solenoid es is also deenergized so that the released-compression of the spring 9'! shifts the valve stem 36 into a right-hand end position so that fluid under pressure within the pipe 90, passes through the valve chamber 94, through the pipe 93, the port '39 into the cylinder chamber 78 to move the piston 6! toward the right. During the initial movement of the piston 6| toward the right, the tension of the springs 10 and II is gradually released during the last motion period until the U-shape frame 63 moves into engagement with the rollers M and 15. Continued movement of the piston 6i toward the right then serves to rock the arm 65 and the rock bar I5 in a clockwise direction (Figs. 2 and 5) to separate the master cam 28 from the follower roller and to separate the cam being ground from the grind-'- ing wheel 22. During the last motion interval before the U-shape frame EBengages the rollers :74 and T5, the plunger H has moved into engagement with the cam faces H0 and thereafter into engagement with III to lock the lever when the high point of the master cam 28 moves into engagement with the follower roller 50. It will thus be seen that provision has been made for automatically separating the master cam from the follower roller when the high point qftne master cam is in engagement with thefollower roller and when the high point of the cam "being ground is in engagement with the grinding wheel. I

The arm N32 is preferably adjustab'ly mounted on the rock bar I-5'by means of a pair ofscre'w's H5 and lit which pass through elongated slots (not shown) which allow the'arm II12to be ad iusted vertically so as to vary the time at which the limit switch 405 is opened during the normal oscillation of the rock bar I5.) As above men'- tioned the arm N12 is preferably positioned so as to open the limit switch 595 slightly before the high point of the master cam 28 is engaged with the follower roller 56.

The operation of this improved cam grinding apparatus will be readily apparent from the fore:- going disclosure. A control switch II! in the power lines I'IJI serves to render the electric circuit operative. When a grinding operation'is started, the switch HTis closed to energize the solenoid 98 so that fluid under pressure is assed into the cylinder chamber 1? to cause the piston 6| to move into a left-hand end position thereby swinging the rock bar I5 in a counter-clockwise direction to position the master cam 28 'in opera,- tive "engagement with the follower roller 59'. At th'e'same time the solenoid I09 is; energized to withdraw the plunger I06 so that the taper IUI is out of engagement with the cam faces I I0-I I I thus allowing free movement of the arm 65. The grinding operation continues for a predetermined number of oscillations of the rock bar 15. That is a predetermined number of rotations of the master cam 28 and the cam being ground ac cording to the setting of the adjustable electric counter Iilii. After a predetermined number of oscillations of the rock bar IS, the counter I09 breaks a circuit to deenergize'the solenoid I09 3 thus releasing the compression of the spring 18 to move the taper 1G1 into engagement with the cam faces HBI l I. At the same time the solenoid 98 is deenergized and the release compression of the spring 91 shifts the valve stem 86 toward the right so that fluid under pressure is passed from the pipe 90 through the valve 85, the pipe 93, the port 19 into the cylinder chamber 78 to move the piston 6| toward the right thereby rocking the rock bar ii in a clockwise direction to separate the master cam 28 from the follower roller 5| when the high point of the master cam is in engagement therewith and when the high point of the cam being ground is in engagement with the grinding wheel.

It will thus be seen that there has been pro vided 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 embodiment 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 machine having a pivotally mounted rock bar, a rotatable master cam spindle thereon, a master cam on said spindle, a follower roller cooperating with said master cam, means to rotate said spindle so as to impart a controlled oscillation movement to said rock bar, a cam on said rock bar, a follower movable into engagement with said cam, a compression spring normally tending to move said follower into engagement with said cam, said follower and cam being shaped so that the follower when in engagement with said cam serves to limit the rocking movement of said rock bar, a solenoid normally to maintain said follower in an inoperative position, and electrical control means to deenergize said solenoid after a predetermined grinding operation has been completed to allow the follower to move into engagement with said cam to facilitate separation of the master cam andfollower roller when the high point of the master cam is in engagement with the follower roller.

2. In a cam grinding machine having a longitudinally movable table, a rock bar pivotally mounted on said table, a rotatable master cam spindle on said rock bar, a master cam on said spindle, a rotatable follower roller on said table, means rotatably to support a camshaft to be ground in axial alignment with the spindle, means to rotate said spindle and camshaft to impart a controlled rocking movement to said rock bar, an arm on said rock bar, yieldable means acting on said arm to maintain the master cam in operative engagement with the roller during a grinding operation, a cam on said arm, a slidably mounted follower arranged to move into engagement with said cam, a compression spring normally to maintain said follower in engagement with said cam, an electric solenoid which when energized serves to hold the follower in an inoperative position, and an electric counter actuated by the oscillation of the rock bar to deenergize said solenoid after a predetermined number of oscillations of the rock bar to stop the oscillation of the rock bar when the high point of the master cam is in engagement with the follower roller.

3. In a cam grinding machine having a longitudinally movable table, a rock bar pivotally mounted on said table, a master cam spindle on said rock bar, a master cam on saidspindle, a follower roller on said table, means rotatably to support a camshaft to be ground in axial alignment with said spindle, means to rotate said spindle to rotate the camshaft to be ground and to impart a controlled rocking movement to said rock bar, an upwardly extending arm on said rock bar, yieldable means acting on said arm to maintain the master cam in operative engagement with the follower roller during a grinding operation, a piston and cylinder to rock said arm and rock bar to an inoperative position, a solenoid-actuated control valve therefor, a cam on said arm, a spring pressed taper plunger arranged to engage said cam, a solenoid normally to hold said plunger in an inoperative position, and an electric counter actuated by oscillation of the rock bar to deenergize both of said solenoids after a predetermined number of oscillations of the rock bar to stop the oscillation of the rock bar when the high point of the master cam is in engagement with the follower roller and thereafter to rock the rock bar to an inoperative position.

4. In a cam grinding machine having a longitudinally movable table, a rock bar pivotally mounted on said table, a master cam spindle on said rock bar, a master cam on said spindle, a follower roller on said table, means rotatably to support a camshaft to be ground in axial alignment with said spindle, means to rotate said spindle to rotate the camshaft to be ground and to impart a controlled rocking movement to said rock bar, an upwardly extending arm on said rock bar, yieldable means acting on said arm to maintain the master cam in operative engagement with the follower roller during a grinding operation, a piston and cylinder to rock said arm and rock bar to an inoperative position, a solenoidactuated control valve therefor, a cam on said arm, a spring pressed taper plunger arranged to engage said cam, a solenoid normally to hold said plunger in an inoperative position, an electric counter operatively connected to control both of said solenoids, and a limit switch actuated by each oscillation of the rock bar to impart an impulse to said counter, said counter serving after a predetermined number of oscillations of the rock bar to stop the oscillation of the rock bar when the high point of the master cam is in engagement with the follower roller and thereafter to rock the rock bar to an inoperative position.

RUSSELL P. HOOK.

No references cited.

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