US3584616A

US3584616A - Truing mechanism for grinding wheels

Info

Publication number: US3584616A
Application number: US751152A
Authority: US
Inventors: William P Flohr Jr
Original assignee: Landis Tool Co
Current assignee: Landis Tool Co
Priority date: 1968-08-08
Filing date: 1968-08-08
Publication date: 1971-06-15
Anticipated expiration: 1988-06-15

Abstract

This disclosure relates to a truing mechanism for grinding wheels. A principal feature of the truing mechanism is that the truing roller is in the form of a relatively thin wheel having an axis of rotation parallel to the axis of rotation of the grinding wheel being trued. As a result, it is possible to rotate the truing roller during a first pass across the grinding wheel to perform a rough truing operation and to hold the truing roller stationary during a return pass, even across the rounded corners of the grinding wheel, to perform a light and highly desirable fine finish truing operation.

Description

United States Patent [72] lnventor William P. Flohr. Jr.

Waynesboro, Pa. [21] AppLNo 751,152 [22] Filed Aug. 8,1968 [45] Patented June 15. 1971 [73] Assignee Landis Tool Company Waynesboro, Pa.

[54] TRUING MECHANISM FOR GRINDING WHEELS 10 Claims, 7 Drawing Figs.

[52] US. Cl 125/11 [51] Int. Cl t t B24b 53/00 [50] Field of Search 125/11; 51/161 [56] References Cited UNlTED STATES PATENTS 2,528,621 11/1950 Sweetser 125/11 X 2,664.681 1/1954 Clark.. 3.313.285 4/1967 Price...

Primary Examiner-Harold D, Whitehead All0rney-Diller, Brown, Ramik and Holt ABSTRACT: This disclosure relates to a truing mechanism for grinding wheels. A principal feature of the truing mechanism is that the truing roller is in the form of a relatively thin wheel having an axis of rotation parallel to the axis of rotation of the grinding wheel being trued. As a result, it is possible to rotate the truing roller during a first pass across the grinding wheel to perform a rough truing operation and to hold the truing roller stationary during a return pass, even across the rounded corners of the grinding wheel, to perform a light and highly desirable fine finish truing operation.

PUMP

PATENTEDJUNISIHYI 3,584,616

UJILUHM P. FLOHR,Jr.

ATTORNEYS PATENIED JUN] 5197:

SHEET 3 OF 3 6 REVERSE M.

INVENTOR (AMLUAM P4 FLOHR,Jr.

BY GM; 35g

TRUING MECHANISM FOR GRINDING WHEELS This invention relates in general to new and useful improvements in truing mechanisms for grinding wheels, and more particularly to a truing mechanism which will permit a fine truing operation across the entire operative face of the grinding wheel, including the rounded corners thereof.

In the past it has been found that a single diamond truing device will produce a much finer surface on a grinding wheel. On the other hand, the life of a single diamond truing device is relatively short and therefore, on production grinders it is desirable to utilize a truing roller.

In order to not sacrifice the quality of finish obtainable with a single diamond, in the past, during the return truing operation, the truing roller has been held stationary as it passes across the peripheral face of the grinding wheel. However, it has not been possible to hold the truing roller stationary as it passes around the rounded corners of the grinding wheel due to the relationship of the truing roller relative to the grinding wheel.

In accordance with this invention, there is provided a novel truing mechanism wherein the relationship of the truing roller with respect to the grinding wheel is such that the truing roller may be held stationary during the entire return pass thereof across the grinding wheel whereby the truing roller is stationary not only as it passes across the peripheral face of the grinding wheel, but also as it passes around the rounded comers thereof.

A principal feature of this invention is the provision of a truing roller which has an axis of rotation parallel to the axis of the grinding wheel being trued.

Another feature of this invention is to provide a truing roller which is very thin as compared to the thickness of the grinding wheel being dressed and at the same time is of a large diameter as compared to existing truing rollers whereby the desired relationship between the truing roller and the grinding wheel to effect a fine truing operation on the grinding wheel and at the same time to provide for the desired long life of the truing roller.

Another feature of this invention is to provide in a truing mechanism for a grinding wheel a profiling assembly which includes a fixed profile and a cooperating follower, the follower having sliding contact with the profile and being of a size and shape corresponding to the size and shape of the peripheral portion of the associated truing roller.

Another feature of this invention is the utilization of a highly desirable friction type brake for quickly and effectively stopping the rotation of the truing roller at the end of one pass thereof across a grinding wheel and to retain the truing roller in such fixed position during the return pass thereof.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings:

IN THE DRAWINGS FIG. I is a schematic plan view showing the operational environment of the truing mechanism of this invention.

FIG. 2 is a fragmentary enlarged side elevational view of the grinding wheel of FIG. 1 and shows specifically the details of the truing mechanism.

FIG. 3 is an elevational view of the truing mechanism of FIG. 2, as viewed from the left side thereof with parts broken away and shown in section.

FIG. 4 is a fragmentary horizontal sectional view taken along the line 4-4 of FIG. 3 and shows specifically the mounting ofthe truing mechanism.

FIG. 5 is a fragmentary sectional view taken along the line 5-5 of FIG. 3 and shows specifically the details of the brake mechanism.

FIG. 6 is a fragmentary vertical sectional view taken along the line 6-6 of FIG. 5 and shows further the details of the brake mechanism.

FIG. 7 is a schematic showing the relative movement of the truing roller as compared with a profile for controlling the movement thereof.

Referring now to the drawings in detail, reference is made first to FIG. ll wherein the general environmental structure of the truing mechanism is illustrated. It will be seen that the truing mechanism, which is generally referred to by the numeral 10, has the diamond impregnated truing roller 1 I thereofillustrated in engagement with a grinding wheel 12 and performing a truing operation thereon. The movement of the truing roller 11 relative to the grinding wheel 12 is controlled by a fixed profile 13 which is engaged by a follower assembly 14 including a follower 15 which is in direct sliding contact with the profile 13 and which is of the same width as the truing roller 11 and has an end contour corresponding to the peripheral contour ofthe truing roller II.

The manner in which the truing mechanism 10 is operated is more specifically disclosed in the commonly assigned U.S. Pat. No. 3,121,423 of Ralph E. Price, et al. granted Feb. 18, I964. Accordingly, there will be described here only such operation of the mechanism for shifting and positioning the truing mechanism 10 as will be necessary to understand the invention.

The truing mechanism 10 is mounted on a truing bar 16 which is carried by a slide I7 for movement toward and away from the axis of the grinding wheel 12. The slide 17, in turn, is slidably mounted on a carriage 18 which is mounted for traverse movement parallel to the axis of the grinding wheel 12. The carriage 18 is mounted on a suitable portion of the bed (not shown) of the grinding machine of which the grinding wheel 12 is a part.

The truing mechanism 10 is advanced and retracted by means ofa cylinder 20 which is secured to the slide 17 and in which there is positioned a piston 21. The piston 21 has a piston rod 22 coupled to the carriage 18. The piston 21 and the cylinder 20 normally function to hold the follower 15 in engagement with the profile 13. The actuation of the cylinder 20 is controlled by means ofa valve 23 which is connected to a suitable pressure pump 24. The valve 23 is, in turn, actuated by

suitable solenoids

25 and 26.

Traversing movement of the carriage 18 is effected by means of a piston 27 which is mounted within a cylinder 28. The piston 27 has a piston rod 29 connected to the carriage 18. The movement of the piston 27 is controlled by means ofa conventional valve 30 which is connected to the pump 24 for receiving fluid under pressure therefrom. The valve 30 is actuated and positioned by means of a pair of solenoids 3i and 32 in a conventional manner.

Referring now to FIGS. 2 and 4 in particular, it will be seen that the truing mechanism It) includes a rigid frame 33 of a suitable configuration. The frame 33 is removably secured to the truing bar 16 by means of a plurality of fasteners 34.

As is best shown in FIGS. 3 and 4, the lower portion of the frame 33 supports a spindle assembly 35 which includes mounting cars 36 having slotted openings 37 therein receiving fasteners 38 which secure the spindle assembly to the frame 33.

The spindle assembly 35 includes a shaft 40 which is mounted for rotation and which is firmly supported so as to be free of vibrations. One end portion of the shaft 40 has mounted thereon the truing roller 11 while the other end of the shaft 40 is provided with a dual grooved pulley 41 for effecting the driving of the shaft 40.

The upper portion of the frame 33 is provided with a motor support 39, the upper portion of which has mounted thereon a motor bracket 39A supporting a power unit 42 which is preferably in the form of an electric motor, but which may be in the form of any desired type of power unit. It is to be understood that the power unit 42 is of a conventional type and is mounted on the motor bracket 39A in a manner wherein it may be vertically adjusted. The power unit 42 is provided with a dual grooved pulley 43 which is aligned with the pulley 41 and which is drivingly connected thereto by means of belts 44. It is to be noted that the

pulleys

41 and 43 and the belts 44 are encased within a housing 45.

The frame 33 also has secured thereto a coolant head 46 for distributing coolant on the truing roller 11 and the grinding wheel 12 during a truing operation. A coolant supply line 47 is suitably connected to the coolant head 46.

The truing mechanism also includes a brake which is generally referred to by the numeral 48 (FIG. 3). The brake functions to both stop the rotation of the truing roller 11 and to hold the truing roller 11 against rotation during one part of a truing operation on a grinding wheel. Basically, the brake 48 includes a brake drum 49, which is mounted on the shaft 40 adjacent to and outwardly of the truing roller 11, and a pair of

opposed shoes

50 and 51 which are engageable with the brake drum 49 in diametrically opposed relation.

Referring now to FIG. 6 in particular, it will be seen that the brake 48 is carried by a mounting plate 52 which is adjustably secured to the frame 33 by means of a plurality of fasteners 53 to assure the alignment of the

shoes

50, 51 with the brake drum 49. The mounting plate 52 has mounted thereon for pivotal movement a pair of shoe supports 54 and 55 which are best illustrated in FIG. 5. The shoe support 54 carries the shoe 50 while the shoe support 55 carries the shoe 51 with the shoe supports 54 and 55 being pivotally mounted on

pivots

56 and 57, respectively.

In order that the

shoes

50 and 51 may move in unison, the shoe supports 54 and 55 are interconnected. It is to be noted that the shoe supports 54 and 55 have overlapping

end portions

58 and 60, respectively. The end portion 60 carries a hardened ball 61 which is engaged with a hardened insert 62 carried by the end portion 58.

At this time it is pointed out that the

shoes

50 and 51 are constantly urged away from the brake drum 49 by means of a tension spring 63 which is coupled to the shoe support 54. The spring 63 urges the shoe 511 in a counterclockwise direction with the result that the hardened insert 62 will move to the right, moving the ball 61 to the right and urging the shoe 51 in a clockwise direction.

The

shoes

50 and 51 are moved into contact with the brake drum 49 by means of a lever 64 which is secured to the shoe support 55 and which is actuated in a manner to be described hereinafter. It is to be noted that the lever 64, when actuated, urges the shoe 51 in a counterclockwise direction. At the same time, the ball 61 will move to the left, moving the insert 63 to the left and effecting clockwise movement of the shoe 50 into engagement with the brake drum 49.

It is to be understood that the structure of the shoe supports 54 and 55 may vary. In a like manner, the construction and attachment of the

shoes

50 and 51 may vary. Accordingly, no attempt has been made to show the specific details thereof. On the other hand, it is pointed out that it is preferred the shoe support 55 be of a two-piece construction with the two pieces being connected together by fasteners whereby the angular relationship of the two pieces of the shoe support 55 may be slightly varied so as to assure simultaneous contact of the

shoes

50 and 51 with the brake drum 49.

Referring now to FIGS. 2 and 3 in particular, it will be seen that there is secured to the central portion of the frame 33 a fluid motor 67. The fluid motor 67 includes a combination bracket and cylinder 66 and is attached to the frame 33 by means of the bracket. The fluid motor 67 also includes a piston 69 which is positioned within the cylinder 66 for relative axial movement. The lever 64 is provided with an adjustable pin 70 which engages the exposed end of the piston 69 eccentrically of the center thereof.

Fluid is supplied into the cylinder 66 through a fitting 71. When fluid under pressure is directed into the cylinder 66, the piston 69 will move to the right, as is shown in FIG. 2, swinging the lever 64 in a clockwise direction so as to actuate the brake 48. It is to be noted that the lever 64 is normally retained in a brake releasing position by means of a tension spring 72 which has one end connected to the upper end of the lever 64 and the opposite end connected to the cylinder 66. It is also to be noted that the tension spring 63 is connected to the cylinder 66.

At this time it is pointed out that the brake drum 49 is in the form of a detachable sleeve which is suitably mounted on the shaft 40 in any desired manner. The brake drum 49 and the truing roller 11 are readily removable from the shaft 40 by the removal ofa retaining nut 73 which is clearly shown in FIG. 3. It will be readily apparent from FIGS. 3 and 4 that the truing roller is in the form of a relatively thin wheel. In actual practice the wheel has a width of 0.1875 inch and a diameter on the order of 3 inches. In addition, it is to be noted that the truing roller has rounded corners. These rounded corners not only facilitate the proper truing of the rounded corners of the grinding wheel 12, but also facilitate the movement of the follower 15 around the contours of the profile 13, as is best shown in FIG. 7. It is to be noted that the contour of the follower 15, which corresponds to that of the truing roller 11, is clearly shown in FIG. 7.

Referring once again to FIG. 1, it will be seen that the operation of the brake 48 is controlled by means ofa valve 75. The valve 75 is suitably connected to the pump 24 and the actuation thereof is controlled by a solenoid 76.

At this time it is also pointed out that the actuation of the valve 30 for controlling the transversing of the carriage 18 may be controlled by suitable limit switches, such as the limit switch 77 which is operable by means of an abutment 78 carried by an extension of the carriage 18. In addition, it is to be noted that the limit of retraction of the slide 17 may be controlled by a limit switch 80 which is engaged by an abutment 81 carried by the slide 17.

OPERATION Referring now generally to FIGS. 1 and 7, it is to be un derstood that the truing roller 11 will normally be disposed in a retracted position at one side of the grinding wheel 12. At this time the follower 15 will be out of contact with the profile 13. When it is desired to initiate the truing operation, the solenoid 31 will be actuated to shift the valve 30 to a position where fluid is directed into the left hand end of the cylinder 28, thereby moving the carriage 18 to the right until the follower 15 is aligned with the profile 13 adjacent a corner portion thereof. Then with the truing roller 11 being rotated by the power unit 42, the valve 23 directs fluid into the cylinder 20 so as to urge the slide 17 toward the grinding wheel 12 with the result that the follower 15 comes into contact with the profile 13 and the truing roller 11 engages the grinding wheel 12 at the left-hand corner thereof. Then, while the slide 17 is still urged toward the grinding wheel 12, the valve 30 is actuated to move the carriage 18 to the right with the result that the follower 15 moves around the left-hand corner of the profile 13 for the truing roller 11 to dress the left-hand corner of the grinding wheel 12. Then the carriage 18 is moved further to the right with the peripheral face of the grinding wheel 12 being trued. Thereafter, as the carriage 18 continues to move to the right, the right-hand corner of the grinding wheel 12 is trued. When the carriage and slide reach a predetermined point in the truing of the right-hand corner of the grinding wheel 12, the movement of the carriage 18 is reversed. At this time, the power unit 42 is deenergized and the brake 48 is actuated to not only stop the rotation of the truing roller 11, but also to hold it in a fixed position.

The carriage 18 moves back toward the starting position thereof until the follower 15 is in contact with the profile 13 at the right-hand corner thereof, after which the truing roller 11 is again moved to the left, truing the right-hand corner, the peripheral face and the left-hand corner of the grinding wheel 12, after which the mechanism is deenergized.

It is to be understood that during the first pass across the grinding wheel 12 by the truing roller 11, since the truing roller 11 is rotating, the truing operation will be a rough truing operation. However, since the truing roller is fixed against rotation when making the return pass across the grinding wheel 12, it will be seen that the second passperforms a light truing operation. Thus, the grinding wheel 12 is reshaped to the desired contour and at the same time provided with the desired finish without an undue wearing away of the truing roller.

It is to be understood that in view of the specific configuration of the truing roller and the fact that it rotates about an axis parallel to the axis of the grinding wheel 12, it is possible for the truing roller to be fixed against rotation during the reverse pass thereof across the grinding wheel 12 so that not only may the peripheral face of the grinding wheel 12 be dressed while the truing roller is fixed against rotation, but also the two corners thereof.

Although only a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made in the truing mechanism and the operation thereof without departing from the spirit of the invention.

I claim:

1. A mechanism for truing a grinding wheel having a peripheral grinding face merging with rounded corners, said mechanism comprising a truing roller, means for moving said truing roller along a path corresponding to the profile of the grinding face and corners first in one direction and then in return, means for rotation said truing roller during the movement thereof along said path in said one direction to thereby perform a relatively heavy initial truing operation, and means for stopping said truing roller at the end of movement in said one direction and for holding said truing roller against rotation during said return movement thereof along said path including said grinding wheel corners to thereby perform a relatively light final truing operation on both the grinding face and corners of the grinding wheel.

2. The truing mechanism of claim 1 wherein said truing roller has an axis of rotation disposed parallel to the axis of rotation of the grinding wheel.

3. The truing mechanism of claim 1 wherein said truing roller has an axis of rotation disposed parallel to the axis of rotation of the grinding wheel, and said truing roller is in the form ofa thin wheel having rounded corners.

4. The truing mechanism of claim 1 wherein said truing roller is in the form of a thin wheel having rounded corners.

5. The truing mechanism of claim 1 wherein said means for stopping and holding said truing roller against rotation includes a brake for both stopping the rotation of said truing roller and holding said truing roller against rotation.

65. The truing mechanism of claim 1 wherein said means for moving said truing roller along said path includes a fixed profile and a follower having nonrotational sliding contact with said profile, and said follower being of a contour corresponding to the face contour of said truing roller.

7. A method of truing a grinding wheel having a peripheral grinding face merging into rounded corners, said method comprising the steps of subjecting the grinding wheel to a rotatable truing roller and rough truing the peripheral face and rounded corners thereof while moving the truing roller in one traverse direction, stopping the rotation of the truing roller of said movement and holding said roller against rotation and when subjecting the grinding wheel to the nonrotating truing roller and lightly truing the peripheral face and rounded corners thereof while moving the truing roller in a reverse traverse direction.

8. The method of claim 7 wherein said truing roller is rotated about an axis parallel to the grinding wheel axis during the rough truing.

9. The truing mechanism of claim 1 wherein said truing roller is in the form of a wheel having rounded corners.

10. A mechanism for truing a grinding wheel having a peripheral grinding face merging with rounded corners, said mechanism comprising:

a. a diamond impregnated truing roller rotatable about an axis parallel to the axis of said grinding wheel,

b. means for moving said truing roller axially along a path corresponding to the profile of the grinding face and corners, first in one direction and then in the return direction,

c. a profile bar,

d. a follower in contact with said profile bar and movable with said truing roller for guiding said roller along said path,

e. means for rotating said truing roller during the movement thereof along said path in said one direction to thereby perform a relatively heavy initial truing operation,

f. and means for stopping said truing roller at the end of movement in said one direction and for holding said truing roller against rotation during movement thereof in said return direction along said path including said grinding wheel corners to thereby perform a relatively light finish truing operation on both the grinding face and corners of said grinding wheel.

Claims

3. The truing mechanism of claim 1 wherein said truing roller has an axis of rotation disposed parallel to the axis of rotation of the grinding wheel, and said truing roller is in the form of a thin wheel having rounded corners.

6. The truing mechanism of claim 1 wherein said means for moving said truing roller along said path includes a fixed profile and a follower having nonrotational sliding contact with said profile, and said follower being of a contour corresponding to the face contour of said truing roller.

10. A mechanism for truing a grinding wheel having a peripheral grinding face merging with rounded corners, said mechanism comprising: a. a diamond impregnated truing roller rotatable about an axis parallel to the axis of said grinding wheel, b. means for moving said truing roller axially along a path corresponding to the profile of the grinding face and corners, first in one direction and then in the return direction, c. a profile bar, d. a follower in contact with said profile bar and movable with said truing roller for guiding said roller along said path, e. means for rotating said truing roller during the movement thereof along said path in said one direction to thereby perform a relatively heavy initial truing operation, f. and means for stopping said truing roller at the end of movement in said one direction and for holding said truing roller against rotation during movement thereof in said return direction along said path including said grinding wheel corners to thereby perform a relatively light finish truing operation on both the grinding face and corners of said grinding wheel.