US2058229A - Abrasive tool - Google Patents

Description

Oct. 20, 1936. A. A. HODGKINS 2,058,229

A'BRASIVE TOOL Filed Jan. 20, 1953 I Sheets-Sheet INVENTORJ ALBERT A. HODGlf/MS ATT RNEY- Oct. 20, 1936.

- Filed Jan. 20, 1933 A. A. HODGKINS ABRASIVE TOOL 2 Sheets-Sheet 2 F I610. e0

INVENTOR- 2,

Patented Oct. 20, 1936 UNITED STATES j PATENT OFFICE,

ABRASIVE TOOL Albert A. Hodgkins, Leonia, N. J., assignor to Surfacing Wheel Corporation,- New York, N. Y.,

a corporation of Delaware Application January 20, 1933, Serial No. 652,622

1 Claim. (CL 29-78) This invention relates to power driven abrading, cutting and polishing tools.

In many situations, articles of manufacture must be treated to remove excess material, en-

built by pouring concrete between forms made of rough boards, show ridges where the boards of the forms joined one another and the whole concrete surface appears rough and unfinished due to the texture of the rough board. In the renovation of articles of manufacture, it is often necessary to remove a coating of paint, or other preservative. And metal articles, such as castings, forgings, metal sheets and plates and the like often have a scale of iron oxide which must be removed prior to use or finishing. Ship bottoms must also be cleaned periodically to remove barnacles.

Heretofore, coatings, encrustations and other surfaces, even on ship bottoms, have been removed by means of wire bristle brushes, grinding wheels of composition or other material, steel burring wheels and the like. Such abrasive means have had a relatively short life. In the case of wire bristle brushes, the bristles spread apart and break after relatively few hours. Grinding wheels, when used on relatively soft material such as wood, copper, aluminum or plastic materials, soon become clogged with the material abraded and have to be resurfaced, that is,

the clogged surface is removed by redressing the surface of the wheel. In a short time, so much of;. the wheel has been removed as to render it in It is also fre-.

capable of further practical use. quently necessary, with existing abrasive devices, to use one tool, such as an emery wheel to cut off the undesired surface and a second tool, such as a wire bristle brush to polish such surface.

For instance, on concrete, to remove the rough spots formed by the wooden forms, and smooth the surface, abrasive wheels, chipping discs and wire brushes are used in conjunction with one another, thus increasing the time required to complete the smoothing operation, as well as the expense thereof.

Certain grades of steel, as they come from the mill, have a hard skin or tough surface which, in ordinary machine handling, requires time to remove and, in its removal, is hard on the present tool steel. I It is now removed in a planer or lshaper or by grinding-wheels or milling machines,

but the removing operation is necessarily slow as the tools overheat and must be run at slow speeds and require constant feeding of a cuttingrfluid to the cutting tool. 7

One object of the present invention -is to pro 5 vide a surface or coating removing devicewhich shallbe more effective than existing devices and which shall have a longer life.

Another object of the invention is to provide a device of the character described which shall both. 10

cut or abrade undesired material and polish the surface in one and the sameoperation- It is also an object of the invention to provide such a device with cutting and polishing teeth of aresilient character which shall retain their. 15

shape and characteristics substantiallyindefinite- 1y, only the cutting edge wearing down to the limit of its effectiveness.

The invention also seeks the provision of teeth for devices of the character described which shallnot crystallize and break in use.

Afurther object of the invention is a tool of the character described having, a plurality of flexible or resilient teeth thereby increasing'the cutting ability of the teeth and giving the teeth a self-cleaning ability.

Still another object of the invention is a device of the character described which ,will avoid overheating. Accordingly, teeth are provided which are spaced from one another on a hub whereby heat is dissipated readily.

Yet another object of the invention is a de- .vice of the character described which will not clog with the material abraded.

The invention seeks further a device of the character .described in which the cutting or polishing teeth are replaceable whereby different degrees of abrasive or polishing. action is obtained and worn teeth may be1replaced as required. I I 1 Furthermore, an abrading tool is sought by this invention, which may be operated at relatively high speeds and no cutting. fluid or cooling medium is required.

I The invention has for another of its objects a device of the character described in which the abrading or polishing elements may not become displaced with respect to one another to leave portions of-the surface not acted-upon.

The invention further seeks a cutting and/or. polishing device which is practical from the standpoint ofease and cheapness' of manufacture and convenience;universality. and durability in use.

These and other objects of the 'inventionand the means for their attainment willbe more apiparent from the following detailed description, taken in connection with the accompanying drawings illustrating various embodiments by which the invention may be realized and in which:

Figure 1 is a view, in side elevation, showing one form taken by the device of this invention;

Figure 2 is a view, in end elevation, looking from the left in Figure 1 and showing one way in which the cutting teeth of this invention may be secured in a hub, parts being broken away in the interest of clearness.

Figure 3 is an enlarged fragmentary sectional view showing the teeth in the hub, taken on the line 3-3 of Figure 2;

Figure 4 is a detail view showing teeth used in cutting or abrading a surface;

Figure 5 is a detail view similar to Figure 4 showing the teeth used in polishing a surface;

Figure 6 is an exploded view showing the blades going to make up one form of the cutting or polishing tooth of this invention;

Figure '7 is a view showing a modified form of the invention;

Figure 8 is a sectional view taken on the plane indicated by the line 88 of Figure '7 and looking in the direction of the arrows;

Figure 9 is a sectional view, taken on a diameter of still another modification of the abrasive wheel of this invention;

Figure 10 is a fragmentary view, on an enlarged scale showing details of construction of the modification of Figure 9; and

Figure 11 is a fragmentary view showing the modification of Figure 9 in side elevation, parts being broken away in the interest of clearness.

In carrying the invention into effect, a plurality of teeth are distributed in spaced relation about the periphery of a hub or wheel.

The cutting or abrading tooth of this invention is laminated. Were a single blade, such as the leaf or lamination l2 of Figure 4, 5 or 6, used and tightly clamped in a holder and moved across a surface at high speed with cutting or abrading friction, it would be deflected substantially in a plane and bend on a transverse line at the point ll (Figure 4 or 5) at which it is secured in the holder. The repetition of shocks, as the holder is revolved, of the blade contacting with the work soon crystallizes the steel of the blade at the line II and causes it to fracture. If, however, the blade I2 is yieldingly reenforced so that it bends in an arc as shown in Figures 4 and 5, no deleterious eifects arenoted and the blade will function until it is worn down after long use to a length less than its designed effective operative length.

As shown in Figures 4 and 5, the cutting or abrading tooth, as a whole, is indicated at II]. It is conveniently comprised of a plurality of formed blades or leaves or laminations of different lengths. The blade [2 is the longest. Back of this blade l2 (considering the direction of rotation as shown by the arrow in thesefigures) is a shorter blade I3 and back of the blade I3 is a still shorter blade l4. Any number of blades as deemed necessary may be used. The respective blades l2, l3 and [4 are shorter for stiifness, as in Figure 4, where abrading is required and longer for greater flexibility as shown in Figure 5 where polishing or use on soft materials is required. The blades are held in a slot IS in a holder l8. In commercial use, a series of such multiple or laminated teeth [0 are disposed about the periphery of a cylindrical holder, as seen in Figures 1 and 2, all disposed in the same plane,

equally spaced about the circumference. Then,

as the holder revolves, the teeth come into contact with the surface to be acted upon, in succession, each tooth removing a portion of the surface.

The hub may comprise one or a plurality of discs or holders 20 each formed with a plurality of the radial slots l6, preferably equally spaced about the periphery. The thickness of each disc 20 is less than the width of the teeth In so that the teeth extend outwardly on both sides, as shown in Figure 3. To hold the teeth in the slots, teeth retaining means are provided. In the modification of Figures 3, 4, 5 and 6, the blades l2, l3 and I4 are notched, as at 22, preferably with rectangular notches, and the notches register with one another when the blades are assembled into a tooth. When the series of teeth is inserted in a disc I8, rings 24 of substantially rectangular cross-section are inserted in the notches and prevent the withdrawal or displacement of any one tooth or any one blade l2, [3 or 14. The thickness of each ring is preferably the same as the depth of the notch or slot 22 in the tooth and the ring fits snugly therein.

In those situations where a wider cutting or abrading surface is required than may conveniently be provided by a single tooth, a plurality of rows of teeth may be provided. The teeth in the several rows are preferably staggered, respectively, as shown in Figure 1, and overlap one another so that the entire area of the surface to be acted upon is treated by the teeth as the wheel revolves and no ridge of untreated material is left between the treated surfaces. Each tooth of the next adjacent series is slightly behind the tooth next ahead of it in order to permit the overlapping of adjacent teeth, that is, it is in a different radial plane through the axis.

As seen in Figures 1, 2 and 3, the several series of teeth are numbered H1, Hi), 2) and 3"], respectively. It is for the purpose of permitting the blades to overlap, as shown, that the slotted discs [8 are made narrower than the blades by the Widths of the two retaining or looking rings 24. The rings 24 serve as spacers to separate the adjacent discs and permit adjacent teeth to overlap by being disposed one in a radial plane between the other. The discs 20, I20, 220, 320, etc. are assembled on an arbor 26 and clamped between end plates or end discs 28, Figure 3, the discs being all suitably apertured to receive the arbor. The assembly is held on the arbor in any convenient manner as against a back up collar 30 by a nut 32 and washer 34.

Obviously only one series of teeth l0 may be used where a narrow cutting member is required, in which case one disc 20 suitably provided with teeth I0, is clamped between end plates 28. The

disc or discs and end plates comprise the hub' member of the tool.

It may be desirable, in some situations, that the front lamination, i. e., that lamination having the abrading edge, be of a different and/or higher grade or heavier material than the socalled backing up laminations.

In Figures 7 and 8, a modified tooth is illustrated. As before, the tooth comprises a plurality of blades 36, 38, 40, 42, 44 and 46, each one slightly shorter than the tooth immediately in front of it (considering the direction of rotation as shown by the arrow). The disc or hub 48 is formed, as before, with a plurality of radial slots, one of which is shown at 50, and, in the lowermost part, the slot is widened as a rectangular passage 52 with downwardly and outwardly slop-v ing walls 53. The lower end of, preferably, an equal number of the blades on each side is bent away from the other group, as at 54, parallel to the wall 53 of the slot and the bent ends 55 are locked against displacement, that is, wedged fast by a transverse rectangular pin or slug 56. Here again, the cutting blade 36 is backed by a Series of shorter blades each one slightly longer than the blade immediately therebehind so that the blade will have flexibility and tend to bend on an are when in contact with the work. By virtue of the Width of the slot 50, as viewed in Figure 7, greater flexibility of the tooth is aifo-rded since a greater number of backing up spring members 38, 40 etc. can be used, as shown, for a given length of tooth. Obviously, any means of securing the teeth in the hub may be availed of.

In the modification of Figures 9, and 11, a tool with a single series of teeth is shown. Such a tool is adapted particularly for small molded articles of relatively soft material or where a corner is to be cleaned.

A circular disc 69 is formed, at its periphery, with a plurality of radial slots 62 to receive the teeth 64, 65 and 66 of this invention. The disc is of substantially constant thickness throughout and is formed centrally with an aperture 68 of convenient size to receive, say, the arbor of a motor.

On either side of the disc 60 is an end plate 10. The two end plates are identical in construction, merely facing in opposite directions. They are of substantially the same diameter as the disc 60 and are utilized to retain the teeth in position. They, too, are formed with central apertures 12 of the same diameter as that of the disc 6|].

In the illustrated embodiment, the end plates '36 are formed as castings, interchangeable one with another. They are conveniently reduced in thickness, as at 14, between a hub portion 15 and an annular thickened bearing portion 16 proximate the tooth engaging periphery, the hub '15 and spacing portion 16 contact to properly position the plate and disc and form a rigid construction with the slotted disc. Conveniently, at this shoulder portion 16 of increased thickness, the disc and end plates are secured together, as by the rivets 78 or other fastening means, the heads of which are preferably disposed, partially at least, in depressions formed in the outer faces of the plates or otherwise countersunk.

Outwardly of the shoulder 76, the inner or opposing faces of the end plates are recessed inwardly of the periphery, for a radial distance somewhat greater than the depth of the radial grooves 62 in the disc to receive the teeth. Each recess is formed with, or otherwise provided with, an inwardly directed rib 80 preferably formed with bevelled side walls 82 to receive similarly shaped notches 6| of the teeth.

Thus, in assembly, the teeth 64-66 each comprised of a plurality of laminations 64, 65, 66, in creasing in radial length, are inserted in the peripheral grooves 62. These teeth, being of greater width than the supporting disc Bl], extend outwardly on either side of the disc so that the notches 6| are substantially wholly exposed on the sides thereof. The notches 6| are preferably narrower at their bottom than at the mouth so that the sides 69 are sloping. The two end plates 10 are next applied to the sides of the disc, the circular ribs 80 fitting into the notches in the teeth and the walls of the recesses engaging the sides of the teeth. The tapering surface of the ribs 80 engage the tapering wall 69 of the notches for rigidly securing the blades thereto. Then, when the end plates 10 are clamped against the disc by the rivets 18, the teeth are firmly held in position by the ribs, in the notches of the teeth 64, 65, 66.

The teeth are held against lateral displacement by the end plates. They cannot be removed from the slots because of the ribs 80 and the radial walls of the slots hold the teeth in a radial direction.

If desired, the several plates or leaves forming a tooth may be permanently secured together as a unit, as by spotwelding at, for instance, the point 84, Figure 10.

The tool of this invention replaces all of the existing abrading and polishing brushes, wheels, etc. now on the market. It cuts and removes rust and scale on metal. It will also abrade hard and soft metals, moulded material and wood. It polishes the material where it has abraded it in one and the same operation. It will remove paint from wood and smooth the roughened surface of cement more efiiciently and quicker than wire brushes and has a life many times greater than wire brushes used in this situation.

The resilient backing of the cutting tooth per:

mits each tooth to bend in an are instead of on a line at the point of its security in the retaining hub and, therefore, there is no tendency for the tooth to break.

Due to the open spaces between the blades the temperature of the tool is kept very much lower than the temperature of the metal being acted upon. Moreover, where soft materials, such as wood, copper, aluminum and moulded synthetic resinoids are acted upon, the material removed does not clog the teeth but probably due to the resiliency thereof, the material is thrown clear of the tool.

It will thus be seen that a cutting tool is provided which is self-cleaning and self-cooling and that the cutting or abrading elements thereof do not clog and do not crystallize due to the supporting leaves which hold the cutting, i. e., the longest blades, toa curved flexure instead of to a hinged flexure. With a relatively small number of disc diameters complete units of any desired diameter can be secured while the length of the tool can be readily varied by adding or subtracting units in the assembly.

Various modifications will occur to those skilled in the art in the configuration, composition and disposition of the component elements retaining the teeth in position as well as in the number and disposition of such teeth and no limitation is intended by the phraseology of the foregoing specification or illustrations in the accompanying drawings.

What is claimed is:

In a rotary abrasive tool, a hub member and a plurality of flexible laminated teeth carried radially with the hub member, the respective laminations of each tooth lying in radial planes and increasing successively in radial length in the direction of rotation of the hub member, the inner ends of said laminations lying in the same plane whereby the lamination on the side toward the direction of rotation is the longer and serves as the abrading edge.

ALBERT A. HODGKINS.

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