US1949511A

US1949511A - Grinding machine table operating mechanism

Info

Publication number: US1949511A
Application number: US329458A
Authority: US
Inventors: Carl G Flygare
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1928-12-31
Filing date: 1928-12-31
Publication date: 1934-03-06
Anticipated expiration: 1951-03-06

Description

March 6, 1934. c FLYGARE 1,949,511

GRINDING MACHINE TABLE OPERATING MECHANISM Filed Dec. 31, 1928 W 556 5 Car/ gar? Patented Mar. 6, 1934 UNITED STATES PATENT! OFFICE Carl G. Flygare, Worcester, Mass., assignor to Norton Company, Worcester, Mass., a. corporation of Massachusetts Application December 31, 1928, Serial No. 329,458

11 Claims.

This invention relates to grinding machines and more particularly to a mechanism for operating a grinding machine table and controlling the speed thereof.

In grinding many types of work, and particularly with a wide wheel fed directly and continuously into the work, it is often desirable to move the wheel first rapidly towards the work and then at a slower rate to grind the work and perhaps at a still slower speed to finish grind it, or to stop the wheel movement altogether. For rapid production methods the wheel feed should be substantially automatically controlled and the changes in its speed should take place when the wheel has reached certain definite locations. For example, in grinding crankshafts and other similar objects in which not only the cylindrical portion of the crankpin but also the cheeks and fillets adjacent the end of the crankpin are 20 ground, it is necessary to move the grinding wheel through a considerable distance to position it in proper relation with the object to be ground and also to remove it therefrom to an inoperative position. In grinding the pin, it is desirable that the grinding wheel be fed as rapidly as possible during the idle movement of the wheel and then to have a slower feeding movement to grind the cheeks and the fillets of the pin and a still slower speed to grind the cylindrical portion or body of the pin and a final stopping of the feed or a removal of the grinding wheel when the work has been reduced to the required size.

It is accordingly one object to provide a grinding machine table operating mechanism which is capable of moving the table in a stepped series of uniform speeds.

It is another object of this invention to provide a simplified control for a slidable grinding machine table which is so arranged that when the table has reached a predetermined position .it automatically actuates a mechanism to cause a different but uniform speed thereafter.

It is another object of this invention to provide a fluid pressure mechanism for moving a table which is arranged so that the movement of the table actuates a throttling device in the fluid pressure system, when the table has reached a predetermined position, to change the speed of the table to a slower but uniform rate.

It is still another object of this invention to provide a fluid pressure operating mechanism for a grinding wheel slide which permits a rapid withdrawal and a rapid approach of the grinding wheel into a position adjacent to the surface of the work and is so arranged that the movement of the wheel slide operates automatically, when the slide has reached a predetermined position, to actuate a throttling device in the fluid pressure system and slow down the movement of the 50 wheel slides to a different but uniform speed.

The drawing illustrates one embodiment of the invention as applied to a grinding wheel feed mechanism which is operated hydraulically in these drawings in which like reference nu merals indicate like parts:

Fig. 1 is a fragmentary perspective view partly broken away and partly in section to illustrate the relation of the hydraulic mechanism to a q grinding machine wheel slide; m

Fig. 2 is a longitudinal sectional view through the reversing valve which controls the direction of flow of fluid to the system and showing the valve piston in position to admit fluid to move the wheel slide rearwardly to an inoperative posltion;

Fig. 3 is a longitudinal horizontal section through the throttle valve having the valve stem broken away to show the v-port;

Fig. 4 is a fragmentary sectional view partly broken away showing the connections between the fluid pressure. piston and cylinder and the throttle valve;

I Fig. 5 is a similar fragmentary view with the fluid pressure piston and cylinder removed and @5 the first trigger released and the throttle valve moved to its second position; and

Fig. 6 is a sectional view through one of the stop members on an enlarged scale showing the construction and adjustment of the same.

In accordance with the invention, and as illustrated in the drawing, a grinding'machine may comprise a grinding wheel 11 rotatably mounted on a wheel slide 12 which is slidably supported on the V-way l3 and flat way 14 on the base of the 95 machine. The work piece 16 shown as'a fragment of a crankshaft may bemounted on any of the well-known work supporting and rotating devices in an operative relation to the wheel. The mm wheel slide 12 is moved'toward and from the work piece by a feeding mechanism which is preferably so arranged that the grinding wheel will be given a rapid approaching movement to bring it into a position adjacent to the surface of the work, and then it will be slowed down to a definite and predetermined speed for rough grinding of the work. This speed continues until the wheel has reduced the work to a given size; then the mechanism 0perates to reduce the feed to a still slower but uniform rate to finish grind the piece of work.

In the preferred construction, this mechanism may comprise a fluid-pressure system such as a cylinder 20, which is preferably fixed tothe base of the machine and. a piston 21 which is'slidably mounted therein. The piston 21 is connected to one end of the piston rod 22 which is in turn connected to the wheel slide 12 by a bracket 23 depending therefrom. Fluid under pressure may be admitted to either end of the cylinder 20 to control the movement of the grinding wheel toward or from the work, and this fluid may be obtained from any suitable source of supply, such as a 1 arranged that the operator may manually control the direction of movement of the grinding wheel. To accomplish this, a reversing valve 25 is provided. This valve is preferably of the balanced piston type having the pistons 26 and 2'? slidably mounted within the valve casing 25 on a valve stem 28. Fluid under pressure is admitted through the inlet pipe 30 to the valve chamber 31 and through the pipe 32 to the cylinder chamber 33 to force the piston 21 toward the left, as viewed in Fig. l, to feed the grinding wheel toward the work. Fig. 1 shows the parts arranged for starting the forward feeding movement of the wheel.

In accordance with this invention, the fluid pressure system includes a throttling device arranged to control the fluid flow, and this device is actuated in timed relation with the wheel feeding movement, and preferably by direct connectionswith the wheel slide, so that when the wheel has reached a predetermined position in its forward movement, the fluid flow is throttled to give a different but slower rate of uniform movement. This throttling device may comprise a valve 35 having the

pistons

36 and 37 mounted on a valve stem 38 and arranged in the system to control" the exhaust of fluid from the chamber 34 of the wheel slide driving mechanism. When the piston 21 moves toward the lift, as viewed in Fig. 1, the

fluid in the chamber 34 is forced outwardly through the pipe 39 into the valve chamber 40 in the valve 25. The fluid entering the chamber 40 is then forced through pipe 41 and the V- shaped port 42 into the valve chamber 43 and then outwardly through the exhaust port 44 and the exhaust pipe 45 back to a pump or reservoir from which the flud supply is obtained. This V- port, as shown in Figs. 1 and 3, tapers towards the right (Fig. 1) so that when the piston 36 moves towards the right (Fig. 1) it gradually closes the port. The V-shape of the port permits a fine regulation of the wheel feed at the slower speeds. It will be noted that the V-shaped port is countersunk in the wall of the valve chamber, so that the fluid may have full access to the pipe 41. It will be readily seen from this construction, that the rate of movement of the grinding wheel slide may be readily controlled by properly positioning the valve piston 36 relative to the V-port 42 and so controlling the exhaust of fluid from the cylinder chamber 34 and consequently the rate of movement of the grinding wheel toward the work.

The valve 25 is arranged to control the direction of flow of fluid through the system and is preferably controlled by a manually operable lever pivotally mounted on a stud 51 on the'base of the machine. The lever 50 has a short arm 52 which is connected by a pin 53 to the yoked member 54 on the outer end of the valve 6 3.- By

swinging the lever 50, the positions of the

valve pistons

26 and 27 may be readily changed, when it is desired to reverse the direction of flow of fluid to move the griding wheel towards or from the work. To stop the infeed of the grinding wheel, the lever 50 is shifted into a position 50a (Fig. 1) thereby moving the valve pistons 26 and 2'7 into

positions

26a and 27a, as shown in dotted lines in Fig. 2. In this position of the parts, the valve piston 26 covers the port leading to the pipe 39 which leads to the cylinder chamber 34 and the piston 27 in position 27a covers the port leading to the pipe 32 which leads to the cylinder chamber 33 thereby preventing fluid under pressure from entering either side of the piston 21, and so stopping the movement of the grinding wheel. To reverse the direction of movement of the wheel slide, the operator may shift the lever 50 to a position 50b (Fig. 1) thereby moving the pistons 26 and,2.7 into the positions 261) and 27b (Fig. 2). In this position of the valve, fluid entering through the inlet pipe 30 into the valve chamber 31 passes through the pipe 39 into the cylinder chamber 34 to force the piston 21 toward the right as viewed in Fig. 1 and thereby removes the grinliing wheel from operative contact with the wor One of the objects of this invention is to produce a stepped series of uniform feeds of the grinding wheel. To this end, mechanism is provided which operates in timed relation with the movement of the grinding wheel slide 12 to move the throttle valve piston 36 and partially close the V-shaped port 42 at predetermined intervals in the forward feeding movement of the grinding wheel, -,thereby producing successively slower wheel feeding movements. This may comprise an adjustable stop, and preferably a series of stops, arranged inthe path of a part of the throttling device, such as the valve stem 38. The stops are moved successively out of the path of the valve stem when the table has reached predetermined locations and so permits the throttling valve to be moved successively to definite positions relative to the port 42 and thereby control the flow of fluid in the table actuating system. A simple means for actuating the stops comprises triggers which are successively moved by the moving piston rod 22 and these in turn move the stops away from the path of the valve stem 38.

As illustrated, this mechanism may comprise a lever arranged to rock about a vertical stud 61 secured to the base of the machine. The forward end of the piston rod 22 is provided with a head 62 adapted to contact with the end of an adjustable screw 63 which permits the operator to vary the point at which the head 62 will operate to swing the lever 60. The other end of the lever 60 is provided with an enlarged portion 64 having the adjusting

screws

65, 66 and 6'? passing therethrough and arranged to contact with the projections 68, 69 and 70 of the levers 71, '72 and '73 which are pivotally supported on the vertical stud '74. These levers '71, '72 and '73 are diagrammatically illustrated in Fig. l and are shown in detail in Figs. 4, 5 and 6. The other ends of the levers '71, '72 and '73 are provided with the adjustable stops '15, 76 and 7'? which are mounted on the ends of the rods '78, '79 and 80. The rods '78,

'79 and 80 pass through the ends of the levers '71, j

'72 and '73 respectively and are provided with the

adjustable nuts

81, 82 and 83 which are screw threaded on rods '78, 79 and 80 respectively so that the operator may readily adjust the position of the

stops

75, 76 and 77 relative to their supporting

levers

71, 72 and 73. The stops are thus arrangdd to be moved out of the path of the member 85 mounted on the outer end of the valve stem 38 by the trigger mechanism comprising the swinging levers operated by the piston rod 22. The valve 36 is normally biased to a closed position by means of a spring 86 surrounding the valve stem 38 and interposed between the piston 36 and the valve head. The tension of the spring 86 tends to move the valve piston 36 toward the right, as viewed in Fig. 1, thereby holding the member 85 in contact with the surface of one of the stop pins 75, 76 or 77.

It will be readily seen that when the head 62 on the piston rod 22 contacts with the' screw 63 and rocks the lever 60, the screw 65 will contact with the portion 68 of the lever 71 and swihg it into the position shown in Fig. 5, thereby withdrawing the stop 75 from its position in contact with the member 85. Then the released tension of the spring 86 forces the valve piston 36 toward the right to partially close the V-port 42. This movement continues until the member 85 contacts with the second stop 76 which is suitably located to give the desired throttling position to the valve 36.- This operates to give a. slower but uniform feeding movement to the grinding wheel. In this particular case, the rapid approaching movement of the grinding wheel is reduced to a grinding feed suitable for grinding the cheeks or side faces of the work piece. 'This slower but uniform rate of feed continues until the adjusting screw 66 contacts with the portion 69 of the lever 72 and swings the lever and thereby withdraws the stop 76 from engagement with the member 85, whereupon the throttle valve piston 36 moves to a new postion and further closes the V-port 42 and produces a still slower but uniform feed to grind the body or cylindrical portion of the work piece. This slower grinding feed continues until the third adjusting screw 67 contacts with the portion of the lever 73 and swings the stop 77 out of contact with the surface of the member 85 thereby closing the V-port 42 entirely and stopping the exhaust of fluid from cylinder chamber 34 and preventing the feeding movement of the grinding wheel toward the work. This permits the grinding wheel to grind out or finish grind the work. During this iinal or finish grinding period, the operator observes the indicator on the grinding gauge to tell when the work has been properly sized, and he throws the lever 50 from the position illustrated in full lines in Fig. i into position 50?) thereby reversing the direction of flow of the fluid under pressure in the system and removing the grinding wheel rapidly to 'an inoperative position.

By adjusting the screw 63, the operator may vary the time at which the throttle valve operates relative to the position of the grinding wheel slide. By manipulation of the adjusting screws 65, 66

, and 67, the operator may adjust the time at which each

stop

75, 76 and '77 is tripped relative to the movement of the slide 12; and by manipulation of the nuts 81, 82 and 88 the operator may adjust the position of the stops 75, '76 and 77 relative to

levers

71, 72 and 73 so as to vary the amount of movement of the throttle valve piston 36 for each successive step in the feeding movement.

In the use of this type of mechanism, it is necessary to reset the throttle valve 36 after a grinding operaton has been completed before it is in condition for the starting of the next grind ng operation. To accomplish this, a piston- 90 is provided as an integral part of the piston ily apparent from the foregoing disclosure.

27. This piston 90 has a passage 91 (Fig. 2) ex'- tending longitudinally of the portion 92 and having and outlet 93 which moves into or out of alignment with the port 94 in the valve casing 25 when the valve is moved. When the lever 50 is moved into position 50?) thereby moving the

valve pistons

26 and 27 into the positions 26b and 27b, as shown in Fig. 2, to admit fluid through the pipe 39 to cause a rearward movement oi. the grinding wheel, fluid is also forced through the passage 91, outlet 93, port 94 and through pipe 95 to the chamber 96 in the rear end of the throttle valve 35. This fluid under pressure operates against the valve piston 37 to move the

pistons

37 and 36 toward the left, as viewed in Fig. 1, to bring the valve and its locking member 85 to their initial positions, as shown in Figs. 1 and 4. A port 97 is prov ded in the valve 25 to permit fluid to exhaust from the chamber 96 when the valve piston 37 moves rearwardly. The port 97 is connected by a pipe 98 to the exhaust pipe 45. When the reversing valve is in the position shown in Fig. 1, fiu'd may exhaust from valve chamber 96, through pipe 95, valve chamber 99, port 97, pipe 98 and into the main exhaust pipe 45.

When the wheel slide 12 travels rearwardly and the head 62 moves away from the adjusting screw 63, it is desirable that the

stops

75, 76 and 77 be swung back into their normal operating positions in the path of the member 85. To accomplish th's, a construction such as that shown in Fig. 6 is employed. The stop rod 78 is provided with an enlarged portion 100 sliding with'n an opening in the lever '11. con cal collar 101 is slidably mounted on rod 78 and contacts with a projection 102 in the cutout portion 163 of the fixed stud 7a. A spring 104 surrounds the rod 78 and is interposed between the enlarged portion 100 and the col'ar 161. The tension of the spring 10% normally tends to hold the stop and its supporting rod in the operating position so that the stop is in the path of the member 85. As thescrew 65 contacts with the portion 68 of the lever '71, the lever is thereby swung relative to the fixed stud 74 and causes the member 100 to approach the collar 101 thereby compressng the spring 104. .l/Vhen the grinding wheel recedes the released tension of the spring 10% operates to swing the lever 71 and the stop 75 back into the normal operating position as shown in Figs. 1, i and 6. Similar mechanisms for controling the movement of each of the other levers 72 and 73 are employed.

It will be readily apparent from this construction, that when the fluid under pressure is admitted to the valve chamber 96, the

pistons

36 and 37 will move towards the left as viewed in Fig. 1, thereby forcing the member 85 over the ends of the

stops

77, 76 and 75 which spring outward and then swing behind the member 85 into their normal positions. This arrangement automatically sets the throttling valve in its initial starting position as the grinding whee. is moved rearwardly so that the mechanism is ready to start on its forward feeding movement when the grinding wheel is brought into alignment with the next piece of work.

The operation of this mechan sm will be readwill also be seen that various modifications of the mechanism may be made within the scope of my invention as covered by the appended claims.

Having thusv described this invention, what is A frustoclaimed as new and desired to secure by Letters Patent is:

1. A grinding machine comprising a grinding wheel slide, a rotatable grinding wheel on said slide, a fluid pressure mechanism connected to move said slide, a fluid pressure system including a throttling valve to convey fluid to said mechaniim, means tending to bias the valve to a closed position, a member movable with the valve, and a plurality of adjustable stops actuated by movement of the slide which successively engage said member to position the throttling valve and thereby cause the fluid to flow at successively different rates.

2. A grinding machine comprising a grinding wheel slide, a rotatable grinding wheel on said slide, a piston and cylinder connected to feed said grinding wheel rapidly towards the work, a fluid pressure system including a reversing valve to conduct fluid under pressure to and from said cylinder, a throttle valve mechanism in said system, means actuated by movement of said grinding wheel slide to position said throttle valve in a predetermined position depending on the position of the slide to diminish the flow of fluid when the slide has reached a predetermined position and cause the slide to move thereafterat 'a uniform but slower rate, and means to adjust the position of the slide at which said throttle valve is operated.

3. A grinding machine comprising a base, a grinding wheel slide, a rotatable grinding wheel on said slide, a fluid pressure mechanism including a cylinder and piston connected to feed said grinding wheel towards the work axis, a fluid pressure system including a reversing valve to admit fluid to either end of said cylinder, a throttling valve in said system, means actuated by movement of said slide to operate said throttle valve to change the fluid flow when the grinding wheel has reached a predetermined position and thereby cause the grinding wheel to feed at a diflerent but uniform rate, means to adjust the time at which said throttling valve operates relative to the grinding wheel movement, and means to adjust said throttling valve to vary the rate of the fluid flow and the grinding wheel movement.

4. A grinding machine comprising a grinding wheel slide, a rotatable grinding wheel thereon, a cylinder and piston arranged to move said slide to feed the grinding wheel towards the work axis, a fluid pressure system for conveying fluid under pressure to and from said cylinder, a reversing valve interposed in said system, a manual control for said valve arranged to admit fluid to either end of said cylinder, a throttle valve interposed in said system to control the exhaust of fluid from said cylinder to regulate the feeding movement of the grinding wheel towards the work axis, adjustable means actuated by movement of said grinding wheel to partially close said throttle valve and produce a slower but uniform rate of movement of said grinding wheel at a predetermined point, and means to adjust the extent of movement of said throttle valve to regulate the rate of feed of the grinding wheel.

5. A grinding machine comprising a grinding wheel slide, a rotatable grinding wheel thereon, a cylinder and piston operatively connected to move the slide, a fluid pressure system for conveying fluid to and from said cylinder, a reversing valve interposed in said system, a manually operable control for said valve arranged to admit fluid to either end of said cylinder, a throttle valve in said system arranged to control the exhaust of fluid from said cylinder which is normally biased to a closed position, a trigger mechanism arrangedto normally hold said throttle valve open, adjustable means actuated by movement of said slide to trip said trigger mechanism at apredetermined point to permit the throttle valve to partially close and thereby reduce the speed of the slide to a slower but uniform rate when the slide reaches a predetermined position, and adjustable means to control the extent of movement of said throttle valve.

6. A grinding machine comprising a grinding wheel slide, a grinding wheel rotatably mounted thereon, a cylinder and piston arranged to move said slide in either direction, a fluid pressure system for conveying fluid under pressure to said cylinder, a manually operable reversing valve in said system arranged to control the direction of flow of fluid to either end of said cylinder, a throttle valve in said system to control the exhaust of fluid from one end of said cylinder which is normally biased to a closed position, a plurality of triggers arranged to hold said throttle valve open, and means actuated by the movement of said slide to successively trip said triggers to partially close said throttle valve when said slide reaches predetermined positions to produce a stepped series of uniform speeds of the wheel slide.

'7. A grinding machine comprising a grinding wheel slide, a rotatable grinding wheel therefor, a cylinder and piston operatively connected to move the slide, a fluid pressure system for conveying fluid to either end of said cylinder, a reversing valve in said system arranged to control the direction of flow of fluid to said cylinder, a throttle valve in said system arranged to control the exhaust of fluid from one end of said cylinder, a trigger mechanism arranged to normally hold said throttle valve open, adjustable means actuated by movement of said slide to trip said trigger mechanism when the slide reaches a predetermined position, and fluid connections between said reversing valve and said throttle valve to return said throttle valve to its initial position when the reversing valve is changed to move the slide rearwardly, so that the throttle valve is in proper position for starting the next grinding operation.

8. A grinding machine comprising a wheel slide, a rotatable grinding wheel on said slide, a fluid pressure mechanism including a piston and cylinder one of which is connected to feed the grinding wheel towards the work axis, a fluid pressure system including a reversing valve to conduct fluid to either end of said cylinder to cause a rapid approaching or receding of the grinding wheel relative to the work axis, a throttle valve mechanism in said system and means operated in timed relation with the wheel movement to actuate said throttle valve when the grinding wheel has reached a predetermined position and cause a slower but uniform feed of the grinding wheel into the work to size the same.

9. A grinding machine comprising a wheel slide,- a rotatable grinding wheel on said slide, a

fluid pressure mechanism connected to feed the grinding wheel towards the work axis, a fluid pressure system including a valve to conduct fluid to said mechanism and cause a rapid approach of the grinding wheel towards the work axis, means j operated in timed relation with the wheel movement to actuate said valve when the grinding wheel has reached a predetermined position and cause a slower but uniform feed of the grinding wheel into the work to rough grind the grinding wheel towards the work axis, a fluid pressure system including a valve to conduct fluid to said mechanism and cause a rapid approach of the grinding wheel towards the work axis, means operated in timed relation with the wheel movement to actuate said valve when the grinding wheel has reached a predetermined position and cause a slower but uniform feed of the grinding wheel into the work to rough grind the work,

a second means operated in timed relation with the wheel movement to actuate said valve and cause a still slower but uniform feed of the grinding wheel to finish grind the work and a third t means operated in timed relation with the wheel movement to close said valve and stop the wheel feeding movement.

11. A grinding machine comprising a wheel slide, a. rotatable grinding wheel on said slide, a fluid pressure mechanism connected to feed the grinding wheel towards the work axis, a fluid pressure. systemincluding a valve to conduct fluid to said mechanism and cause a rapid approach of the grinding wheel towards the work axis, means operated in timed relation with the wheel movement to actuate said valve when the grinding wheel has reached a predetermined position and cause a slower but uniform feed of the grinding wheel into the work to size the same, and a second means operated in timed relation with the wheel movement to close said valve and stop the feeding movement of the grinding wheel.