US3400498A - Metal polisher - Google Patents

Description

D. F. KITZEL METAL POLI SHER Sept. 10, 1968 5 Sheets-Sheet 1 Filed Aug. 10, 1965 Sept. 10, 1968 D. F. KlTZEL 3,400,498

METAL POL I SHER Filed Aug. 10, 1965 5 Sheets-Sheet INVENTOR.

5 A 7 TOENEY.

Sept. 10, 1968 D. F. KITZEL 3,400,498

METAL POLISHEB Filed Aug. 10, 1965 3 Sheets-Sheet 5 f I INVENTOR. F2 2! w 23 1 United States Patent 3,400,498 METAL POLISHER Deilburt F. Kitzel, 4767 W. 211th St, Cleveland, Ohio 44126 Filed Aug. 10, 1965, Ser. No. 478,539 9 Claims. (Cl. 51-212) ABSTRACT OF THE DISCLOSURE The invention is directed to a polisher particularly adapted for supporting armature shafts for rotation against the polishing face while the face remains in substantially fixed position axially of the shaft, and polishing the shaft uniformly along the entire length of the engaged portion of the shaft to precise cylindrical shape free from circumferential grooves and ridges.

The polisher is in the form of a hard, compact, but slightly resilient body composed of a plurality of strands, each comprising a plurality of unbraided generally parallel wires. The strands are braided together to form a regular repetitive criss-cross pattern, of which the strands extend predominantly lengthwise of the polishing direction but oblique to said direction.

The interstices of the body are filled with fine abrasive grit in carrier material which is flowable under polishing pressure.

This invention relates to a metal polisher for polishing metal surfaces to a smooth finish free from objectionable surface irregularities. More specifically, the invention relates to a metal polisher for polishing surfaces of metal articles to vary precise dimension and mirror finish.

For the purposes of illustration, the polisher is described in connection with the polishing of metal shafts of alternators and the like, such as commonly used on many of the present day motor vehicles, its use for polishing other types of shafts and other metallic members being readily apparent from the illustrative example.

In connection with such alternator's, difiiculty has been encountered in producing consistently precise and highly finished bearing surfaces on the armature shafts which are to operate in rolling engagement with needle roller bearings. Very slight irregularities or lines on such surfaces result in chattering to a degree which is objectionable from the standpoint of noise and detrimental to the alternator parts. Irregularities and lines which cannot be detected readily by the usual inspection procedures nevertheless cause such objectionable operation and are usually not discovered until the alternator is assembled and test operated. If the faulty operation is thus discovered, the only manner of correction is to disassemble the alternator, remove the armature, repolish the shaft, reassemble the parts, and then retest the alternator.

With the present day polishing methods and instruments, such irregularities and lines are not consistently eliminated or reduced to such an extent as to eliminate the chatter and vibration. In the methods currently in use, the polishing is done while turning down the commutators for concentri-city with the shaft. Ordinarily, in turning down the commutator on such an armature, the armature is supported by the end portions of its shaft in upwardly open bearings and is rotated. Generally bearing blocks are pressed downwardly onto the shaft by spring pressure to prevent the shaft from shifting in its bearings. The polishers presently used are carried by, or seated by, the blocks against the upwardly exposed bearing surfaces of the shaft.

If the polishers are maintained in a stationary position axially of the shaft, they do not polish with the degree 3,400,498 Patented Sept. 10, 1968 of precision desired, but, on the contrary, form lines or repetitive patterns of irregularities on the shaft. Attempts have been made to eliminate these lines and patterns by reciprocating the polishers axially of the shaft during the shaft rotation. Reciprocating the polishers improves the results, but does not reduce the irregularities and lines consistently to a degree rendering them innocuous to proper alternator operation.

In accordance with the present invention, a polisher is provided which can be applied on the shaft under yielding pressure while retained in a fixed position axially of the shaft during turning down or polishing of the commutator in the manner hereinbefore described, and which, when so applied, polishes the shaft at the portion engaged by the polisher to a precisely dimensioned mirror finish free from detectable lines or surface irregularities which could adversely affect the operation of the alternator. Furthermore, the present polisher produces such precise mirror finishes without any appreciable reduction in shaft diameter.

Any lines or irregularities which might be present on the precise polished mirror finish are not detectable without substantial magnification and are innocuous insofar as concerns the cooperation of the surfaces with needle roller bearings.

Various specific objects and advantages of the invention will become apparent from the following description wherein reference is made to the drawings, in which.

FIG. 1 is a perspective view of a polisher embodying the principles of the present invention;

FIG. 2 is a right end elevation of the polisher illustrated in FIG. 1;

FIG. 3 is an enlarged fragmentary view of the polisher with the braids expanded to show a preferred relation of the individual wires and strands, and the disposition of impregnating polishing material relative thereto;

FIG. 4 is a fragmentary end view of the structure illustrated in FIG. 3;

FIG. 5 is a top plan view of the modified shape of the polisher;

FIG. 6 is a right end elevation of the polisher illustrated in FIG. 5;

FIG. 7 is a top plan view of another modified shape of the polisher;

FIG. 8 is a right end elevation of the polisher illustrated in FIG. 7;

FIG. 9 is a top plan view of the polisher mounted in a suitable tool support;

FIG. 10 is a right end elevation of the structure illustrated in FIG. 9;

FIG. 11 is a top plan view of a band of braided material embodying the principles of the present invention, and which may be used in the form illustrated or in folded and compacted form;

FIG. 12 is a front elevation of the band illustrated in FIG. 11;

FIGS. 13 and 14 are diagrammatic illustrations of the steps of forming a band of the material, such as illustrated in FIGS. 11 and 12, into a compacted lbody;

FIG. 15 is a perspective view of a tubular form of band used as the starting material for making a compacted polishing body;

FIGS. 16 through 19 are diagrammatic illustrations of successive steps in the forming of the polisher from the starting material illustrated in FIG. 15; and

FIGS. 20 and 21 are diagrammatic illustrations showing the manner in which a polisher of the present invention may be used for polishing the shaft of the armature of an alternator, such as commonly used on automobiles.

In accordance with the present invention, the polisher comprises a compact body v1 which is slightly resilient as distinguished from being extremely rigid and unyielding.

The body is in the form of a block composed of a plurality of strands 2 which are braided together. Each strand 2 preferably comprises a plurality of individual wires 3. The wires 3 of each individual strand preferably are unbraided with respect to each other, and are braided only as a unit with respect to the units forming other strands, due to the braiding of the strands as a whole.

The interstices between the strands and the individual wires of the strands are impregnated with a very fine abrasive grits or powder and a solid carrier material which is flowable under pressure. The impregnation preferably is throughout the entire body, but the polishing face and contiguous strata must be well impregnated.

The polisher may comprise a single layer of strands. However, the polisher preferably comprises a plurality of layers, each layer comprising braided strands as described. In such instance, the layers are arranged in juxtaposed face to face relation, the strands of each layer extending generally parallel to corresponding strands of the other layers. In this application, the direction in which the polisher moves relative to the surface it is polishing is endwise, and the strands extend generally endwise of the polisher, but somewhat oblique to the length of the body.

For polishing the surfaces of a shaft, the operating face of the resultant body 1 is indented with an indentation 5 which extends entirely across the body transversely of the length of the body and, therefore, transversely of the wires 3. Thus when a shaft is resting in the indentation and rotating, the periphery of the shaft travels in a direction generally endwise of the strands 2; for example, from the bottom to the top of the body 1 in the position illustrated in FIG. 1.

The advantages of having the identation disposed transversely of the direction of relative travel of the body 1 and periphery of the shaft are extremely pronounced, as distinguished from an identation which would extend, for example, in the direction of relative travel, or endwise of the body. The body 1, as shown in FIGS. 1 through 4, is particularly desirable for the particular polishing operation heretofore described.

The modification illustrated in FIGS. 5 and 6 is a body 6 of the same general type as the body 1, heretofore described, but it is provided with an indentation 7 at a corner portion.

The indentations 5 and 7 are not the result of cutting away any of the metal of the body, but are the result of bending and deforming the strands during formation of the associated body.

In many cases it is satisfactory to provide a body, such as indicated at 9 in FIGS. 7 and 8, in which an indentation 10 is provided consisting of two planar surfaces 10:: and 10b angularly disposed with respect to each other.

In the modification illustrated in FIGS. 9 and 10, the

body 11 is such as illustrated in FIG. 1 but mounted in r a suitable tool support in the form of a channel 12 in which the body is firmly seated, the body preferably being formed therein in the channel during compaction of the body, as is later described herein. The channel 12 is provided with a shank 13 which is receivable in a suitable tool holder for supporting the polisher in operating position.

Several methods may be employed in the manufacture of the polisher. For example, as shown in FIG. 11, the polisher may be formed of a single band 15 comprised of a plurality of strands braided together, each strand preferably being composed of a plurality of wires which are unbraided with respect to each other. The band 15, while it is in relatively loose condition, as distinguished from a tight, firm band, affords ample opportunity for abrasive grits or powder and flowable carrier material to enter into the interstices between the strands and then between the individual wires. While in this loose condition, the band is impregnated with abrasive powder or grit and the flowable carrier material. When so impregnated, the

band is compressed normal to its face to a relatively rigid, self-supporting, but somewhat resilient body. This body may be of any length desired and of any width. The faces may be planar, curvilinear or of other desired selected configuration.

Instead of a single ply band, the polisher is preferably made up of a plurality of layers of the band material, these layers being juxtaposed in face to face relation and then compressed into final form by the application of pressure normal to the faces. For example, as shown in FIG. 13, the single band 15 is shown as folded back and forth upon itself to provide a stack of portions of band material. Of course, if desired, the band may be cut into lengths and a number of the cut lengths stacked. The layers or stack of band material, with faces juxtaposed, are placed in a cavity of suitable die 17 and are compressed by means of a ram or companion die 16 having a bulge 18, to provide an indentation 19, such as above described, in the resultant body. This manner of making the polisher is quite satisfactory.

As illustrated in FIGS. 15 through 19, another method is disclosed. In this form, the starting material is a tube 20 with strands which are braided together, each strand comprising a plurality of individual unbraided wires, such as illustrated in FIG. 11. The length of the strands is generally lengthwise of the tube but oblique to the length of the tube. The tube is preferably relatively loosely braided so as to provide ample interstices for impregnation. The tube first may be flattened, as illustrated in FIG. 16, by rolling, or by the application of pressure transversely to its longitudinal axis. When thus collapsed and flattened, it may be folded or bent endwise about an axis extending transversely of its length and parallel to its flat faces and the two resultant portions juxtaposed in face to face relation, as illustrated in FIG. 17. The portions thus juxtaposed then may be wound into a coil about an axis extending transversely of its length, to a shape such as indicated in FIG. 18. At any time during this procedure, before or .after it is wound into a coil, it is impregnated with the flowable carrier and the abrasive powder. After impregnation it is placed in a cavity of die 21 and, by a companion die 22, is compacted fiatwise or in a direction normal to its flat faces, into a body, such as hereinbefore described.

The impregnation may be carried out in various ways, the use of hypodermic type needles and the like for pressure injection of the impregnating material, being preferred. The impregnation is such that the material is distributed throughout the entire body.

The wire used for the strands is preferably copper, though other soft wire may be used.

The abrasive or powder should be extremely fine, depending on the time to be used in polishing, the preciseness and degree of finish desired, and the circumferential speed or relative travel speed between the polisher and the surface to be polished. The particle size preferably ranges from minimum size that can be measured up to 5 microns.

The abrasive preferably is diamond grit, silicon carbide, aluminum oxide, and mixtures of all or part thereof. Other well known abrasive grits, depending upon the particular type of metal to be polished, may be used. The diamond is superior, being sharp and retaining its sharpness for long periods of use.

The carrier material is preferably a composition of propylene glycol, stearic acid, castile soap and polymerized ethylene oxide. Other carrier material may be used, the important features being that it is solid, but flowable under pressure so that it and the abrasive are fed to the polishing surface. It preferably has the consistency at room temperature of hard or chilled butter.

An example of the composition of grit and impregnating material is as follows:

Grit up to five microns particle size 2%; Polypropylene glycol Stearic acid 28%;

Castile soap and Polymerized ethylene oxide 10%.

It is desirable that the ends of the bands of braided strands be soldered to prevent unraveling. This is done before impregnation. As mentioned, the strands may be impregnated by the use of a hypodermic type needle so that the material fills the interstices between the various wires, strands and layers, thus being distributed throughout the entire body and thereby providing additional material to be fed out as that at the surface is carried away.

It is preferable that the metallic composition body be the same throughout, but this is not absolutely essential, except for longer life. The important feature is that the polishing face he of the braided, impregnated material as heretofore described.

For reasons not fully understood, it appears that due to the use of the fiowable carrier material with the braided wire, the body resists loading by particles of metal from the part being polished. Due to the slight resilience of the resultant body, the continual feeding of the abrasive material from the inner portion of the body to the surface is effected and replaces any surface material that may be rubbed off or carried away by the surface being polished.

Furthermore, it has been found that with polishers of this character, shafts can be polished precisely to a mirror finish without any objectionable lines or patterns of any nature without any noticeable reduction in the diameter of the shaft as the result of the polishing operation.

Referring to FIGS. 20 and 21, the use of the present polisher for polishing the shafts of the armature of an alternator Av is illustrated. In such case, the shafts rest in the polishers 23, which may be the same as body 1 heretofore described, which acts as a lower bearing for the portion of the shaft to be polished. A suitable fixture 24, having rollers 25, is pressed by a spring 26 firmly and resiliently onto the upwardly exposed surface of the shaft so as to assure its proper contact with the block 23. The polisher 23 and shaft remain in fixed axial position during rotation of the shaft.

The relative surface travel of the polisher and the pe ripheral surface of the shaft is generally endwise of, but oblique to the strands.

If the polisher is used to polish surfaces by being moved to and fro thereon, for example, in hand polishing, the direction of movement of the polisher is preferably endwise of the strands.

Having thus described my invention, I claim:

1. A metal polisher comprising a hard and compact, but slightly resilient, body formed of a plurality of strands braided together in a regular criss-cross pattern to provide a polishing face of which the strands extend predominantly lengthwise of the body, but oblique to the length of the body, each strand being a plurality of relatively soft wires which are parallel and unbraided with respect to each other, and the interstices between the strands being impregnated with fine abrasive grit and a solid carrier material which is flowable under polishing pressures.

2. A structure according to claim 1 wherein the Wires are copper.

Percent Grit of particle size up to 5 microns from the group consisting of diamond, silicon carbide, aluminum oride, and mixtures thereof 2 Polypropylene glycol Stearic acid 28 Polymerized ethylene oxide 10 5. A rnetal polisher according to claim 1 wherein the body is composed of a plurality of layers of said strands, the layers being in face to face juxtaposition and cornpacted in a direction normal to their juxtaposed faces.

6. The metal polisher according to claim 5 wherein the wires of each strand extend from one edge entirely to an opposite edge of the stack.

7. A metal polisher according to claim 1 wherein the body comprises a radially collapsed hollow tube of which the wall is composed of said braided strands, the strands extending generally endwise of the tube oblique to the tube length and having face portions along its length disposed in face to face relation to each other.

8. A metal polisher according to claim 1 wherein the body has an exteriorly exposed polishing portion, the strands of said portion being bent and distorted so as to provide, in the polishing face of said portion, an indentation extending transversely of the length of the body for the full width thereof, and of uniform shape throughout said width.

9. A metal polisher according to claim 1 wherein the criss-cross pattern of the strands exposed in the polishing face of the body is such that half of the strands are oblique to the length of the body at an acute angle to said length and in a direction from the left edge to the right edge and the other strands are oblique at an obtuse angle to the length of the body in said direction.

References Cited UNITED STATES PATENTS 1,147,279 7/1915 Sweetland 15209.5 2,284,738 6/ 1942 Hurst 51400 2,395,068 2/1946 Rimer 15-506 X 2,413,551 12/1946 Englund 15506 X 2,983,941 5/1961 Beyer et a1. 15209.5 3,078,489 2/1963 Miller 15-2095 3,150,470 9/ 1964 Barron 51400 3,175,331 3/1965 Klein 51400 2,780,041 2/ 1957 Larsen 51-304 X 2,899,290 8/1959 Riegler 51-304 2,980,524 4/1961 Morton 51-304 X LESTER M. SWINGLE, Primary Examiner.

D. G. KELLY, Assistant Examiner.

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