US1553552A - Balancing grinding wheels - Google Patents

Description

Sept. 15,1925.

* M. o.'REEvEs BALANCING GRINDING WHEELS Filed July 14. 1922 INVENTOR Wilton Q. J2ee mes,

BY1 l AT ORNEY Sept. l5, 19.25. (E 1,553,552

M. o. REEVES y BALANGING GRINDING WHEELS Filed July 14, 1922 2 Sheets-Sheetv 2 NVENTOR RNEY Patented Sept. 15, 1925.

UNITED STATES PATENT OFFICE.

MILTON O. REEVES, OF COLUMBUS, INDIANA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE HEIM GRINDER COMPANY, OF DANBURY, CONNECTICUT, A. CORPORATION OF CONNECTICUT.

BALANCING GRINDING- WHEELS.

Application led July 14, 1922. Serial No. 574,873.

To all whom t may concern.

Be it known that I, MILTON O. REEVES, a citizen of the United States, residing at Columbus, in the county of Bartholomew and State of Indiana, have invented new and useful Balancing Grinding lVheels, of which the following is a specification.

In the operation of grinders, difficulty has been experienced, to a considerable extent, in a lack of that high degree of accuracy which is desirable, due to a relative chattering between the work and the grinding element.

It has heretofore been commonly supposed that an undesirable condition of this kind was due to lack of rigidity and extreme nicety of it in the supports and bearings for the grinding wheel (and feed wheel in centerless grinders), and users of such machines have heretofore attempted to eliminate the difficulties by tightening the bearings of said wheels. Such manipulation does not, however, result in a cure, and in many instances results in damage to the machine.

A fundamental cause of chattering and lack of accuracy of production is due to a lack of accurate balancing of the grinding wheel. This lack of balancing is likely to occur and recur at any time during the normal operation of the machine and resulting wear of the grinding wheel, the variation in balancing being due to the fact that the grinding element is not entirely uniform throughout its structure and the center of gravity shifts from time to time as the element wears. Heretofore no practical means has been provided by which the average machine could rc-balance the wheels.

The object of my present invention is, therefore, to provide means by which the operator of machines of this type may vary easily and accurately balance and re-balance the grinding wheel as a part of the normal operation and use of the machine.

The accompanying drawings illustrate my invention. Fig. 1 is a perspective view of the Reeves centerless grinder which is wellknown on the market; Fig. 2, a perspective of a fragmentary portion of the base of such machine equipped with a portion of my improvements and showing the grinder element in position to be balanced or re-balanced; Fig. 3, a side elevation of one of the balancing ways designed as an attachment to existing grinding machines; Fig. 4, an end elevation; Fig. 5, a plan; and Fig. 6, an axial section of a grinding wheel equipped with my improved hub construction for facilitating balancing. It will be understood that my invention is applicable to all precision grinding machines.

In the drawings, 10 indicates a suitable base upon which is mounted a horizontally adjustable carriage 11, carrying the grinding wheel 12 which cooperates with the feed wheel 13 and work supporting bar 14, to automatically rotate, axially advance, and grind articles placed in the grinding throat upon the bar 14. The feed wheel 13 is mounted to rotate upon a horizontal axis substantially at right angles to the axis of the grinding wheel 12 and is carried by vertically adjustable carriage 15 mounted on suitable ways on base 10.

The above construction is Well-known on the market and is merely referred to here as typical of a grinding machine.

The grinding and feed wheel elements of machines of this type are generally artificial compositions and are provided with an axial bore 17. Extended through the bore is a sleeve 18 provided at one end with a flange 19. Splined upon sleeve 18 is a collar 20 arranged in opposition to iange 19, the flange and collar being provided with central portions 19 and 20, respectively, which enter and lit the bore 17. The element 12 is clamped iirmly between 'Hange 19 and collar 18 by means of a nut 21 threaded upon the end of sleeve 18. parts 18, 19, 19, 20, 20 and 21 form a chuck for the wheel.

Sleeve 18 is provided with a tapered axial bore 22 adapted to receive an arbor by means of which it is to be supported in the grinding machine.

Thus far, the elements described are common and well-known. It will be, of course, understood that the above reference to wheel 12 is intended to apply to any rotative element which is subject to wear, and because of that wear, varies in its balance, relative to its axis and, consequently, needs re-balancing.

In the above described construction, which is typical of abrasive wheels as they are prepared for use, it has long been well known that, with the wear of the wheel, its center of gravity shifts laterally relative to The its axis of rotation and, in order to balance the wheel upon its axis, 1t has been cus- .tomary to dig out portions from the heavy side of the wheel or, in some instances, to dig out from the light side and insert a heavier substance. Such operations, however, are tedious and, in many instances, require successive withdrawals of the wheel from the balancing ways.

To obtain the best results from grinding machines, the grinding wheel must be kept in very accurate balance., I, therefore, provide a pair of runways or balancing ways 25, 25 which may be permanently incorporated in the machine, or formed by separate brackets as shown in the present drawing, which may be attached to the machine. I prefer, however, that the runways be closely associated with the grinding machine in order that the best results may be most conveniently obtained.

In the present instance, each track or runway 25, is supported, in an accurate horizontal position by means of a bracket 26 provided at its upper corner with a horizontal cross foot 27 and a perforation adapted to receive a horizontal bolt 28, the foot 27 being so shaped as to form a fulcrum upon which the bracket may be rocked. At its lower corner the bracket is provided with a perforation adapted to receive bolt 29 and is so shaped as to normally stand some distance away from the machine base 10 so that a nut 30 may be threaded upon the bolt 29 between the base 10 and the bracket 26 so as to form an adjustable support for the lower end of the bracket, the bracket being clamped in desired position by the nut 31 on bolt 29. Nut 32 on bolt 28 serves to clamp'foot 27 against base 10.

By this arrangement, the bracket 26 may be readily adjusted so as to bring its track 25 into a truly horizontal position so that the pair of tracks 25, 25 will be level and will serve as a support upon which the balancing arbor 33 may roll, said arbor being provided with a central portion 33 adapted to fit the bore 22 of sleeve 18.

Extending through flange 19 and the adjacent portion 19l is a. circumferential series of closely and equally spaced, axially extending holes 35, leading into the annular space which exists between wheel 12 and sleeve 18. Registering with the holes 35 is a circumferential series of threaded holes 36. Each wheel is provided with a plurality of balancing weights 37 in the form of rods having a diameter fitting the holes 35, one end being threaded as indicated at 37 to enter holes 36 and the other end being diametrically slotted, as indica-ted at 37 for the reception of a screw driver. Balancing of the wheel, either initial or subsequent to the period of wear, is acomplished by removing the wheel from its machine arbor, inserting the balancing arbor 33 in the sleeve 18 and placing the arbor on the tracks 25 as indicated in Fig. 2. y

The wheel will, of course, automatically roll until its heavy side is down. The heavy side may then be compensated by a proper insertion of weights 37 on the light side. I have found that the most satisfactory results can be obtained by placing the balancing pins in pairs and on opposite sides of the vertical line of the light-heavy position of the wheel, and in the first holes above the horizontal center, as indicated at 37, 37 in Fig. 6.

The wheel is then again rolled and if it again assumes the same light-heavy position, the two weights are placed in the next higher holes 35. This loperation is repeated until the wheel is balanced or the weights reach the holes nearest the light-heavy line. If these weights are insufficient, a second pair of weights, etc., is utilized as before described. This operation is continued until the heavy portion of the wheel is compensated.

During the balancing operation the weights 37 may be merely inserted into openings 35, without being screwed into final position, but when the best balanced condition has been reached, all of the weights 37 should be screwed tightly into place.

When the wheel has worn to an unbalanced condition, the operation will be repeated, all of the weights 37 being first removed so that the unbalanced condition of the wheel itself may be initially determined.

The term abrasive wheel used in the claims, is intended to cover any rotative element desired to be maintained in balance relative to its axis of rotation and subjected to normal wear which may cause it to reach a condition of imbalance relative to its axis of rotation.

I claim as my invention:

1. The lcombination with an abrasive wheel of a supporting chuck therefor comprising a sleeve member having a periph- -eral shouldered portion for interior engagement with the central aperture in the grinding wheel and having a peripheral flange adjacent the shoulder for clampingly engaging one face of the wheel, a collar splined on the sleeve and having a. shouldered portion for engaging the aperture of the wheel, means for securing the collar on the sleeve to clampingly retain the wheel, the flange and collar being formed with alined apertures extending throu h the shouldered portions thereof interme iate the sleeve proper and wheel, said apertures being adapted to receive balancing members extending transversely of the wheel, substantially as illustrated.

2. The combination with a grinding for mounting said wheel, including a sleeve portion, having a spindle receiving socket, a shouldered portion and an adjacent peripheral flange, a clamp collar on the sleeve, having a shouldered portion filling the space intermediate the sleeve and the wall o-f the aperture in the wheel and balancing members extending transversely of the space thus provided between the wall of the aperture in the wheel and the sleeve, said balancing members extending between the flange and collar and having threaded engagement with one of said parts for removably retaining the balancing member in desired adjusted relation thereto.

3. In a grinding machine a mounting for a wheel having a central bore, comprising a chuck, including a sleeve adapted to be disposed within the bore and means for holding the bore in spaced relation to the body of the sleeve to provide an annular chamber, the chuck being formed with a multiplicity of apertures communicating with said annular chamber and balancing members removably mounted in certain of the apertures and extending transversely of the chamber, whereby an equalized balanciing action is performed by said members transversely of the Wheel and within the bounding planes thereof.

In witness whereof, I MILTON O. REEVES have hereunto set my hand at Indianapolis, Indiana, this 8th day of July, A. D. one thousand nine hundred and twenty tw'o.

MILTON O. REEVES.

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