US 2773338 A
Description (OCR text may contain errors)
Dec. 11, 1956 w. K. CARTER 2,773,338
ABRADING ARTICLE Filed April 5, 1954 I IIVENTOR ji 4 WHur K.Cartr.
A TTORNE Y nitecl States Paten This invention relates to abrading articles. In general, the invention comprises an abrading article formed from a multicellular ceramic product provided with flexible reinforcement.
It has been found that multicellular products, for example, such as disclosed in United States Patent No. 1,945,052; No. 2,156,457 and No. 2,337,672, and known under the trade name of Foamglas, can be used for abrading operations. These products have a great number of adjacent cells, usually devoid of communication with each other, which are extremely fragile and easily shattered. When broken the cell walls have value as an abrasive through the utilization of work surfaces formed from the sharp projecting residues of attached but broken and shattered cell walls. The cell wall shattering and breakage to produce a desired abrasive plane or contoured work surface may be obtained by sawing, cutting, or rubbing.
. The abrasion produced with these cellular structures results from the cutting action of the broken and shattered cell walls which remain attached to the abrading article. Abrasion is also produced from the cutting action of detached and broken-off particles of cell walls which are subject to progressive comminution as they move about upon the work piece. The detached particles are thus capable of producing smoothing of greater degree as comminution progresses.
One of the objects of the invention is to provide an abrading article of the type described having a flexible reinforcement. This feature of the invention provides for strengthening the structure generally and for maintaining broken cell walls in position to be most effective in abrading operations.
It is also an object of this invention to provide a coating substance forming a fringe which extends around the work surface of the abrading article. This fringe provides for holding debris from broken cell walls and cuttings in contact with the work surface.
One of the advantages of using a cellular ceramic product for abrading purposes is derived from the ability to remove clogging debris from the glassy smooth interiors of the partially hemispherically shaped cell por tions forming the cutting surface. The cutting surface may be cleaned simply by tapping or jarring the abrading article while the clogged surface is faced downward so that debris is free to drop away. This allows complete utilization of the abrading article without regard to the surface clogging which limits the usage range of paper coated abrasives. However, in cleaning, the fragility of the structure and the thinness of the cell walls present a disadvantage. The tapping or jarring necessary to free the debris from the work surface requires striking the structure upon an edge and this results in breaking away corner areas or other surface portions which otherwise could have been used for abrading purposes. In accordance therewith, it is another object of the invention to provide a cushioned surface or edge for striking the structure so that it can be 2,773,333 Patented Dec. 11, 1956 jarred or tapped to clean away the debris without causing excessive breaking of the surface structure.
It has been found that these cellular ceramic abrasives are unique in that they have an eraserlike wearing action. Thus, starting with an abrading surface of sharp, thin, broken cell walls, as work is accomplished by movement and pressure, the original sharp walls break and new underlaying walls are shattered and exposed. An abrading article thus formed from a suitable cellular ceramic structure is usable throughout its entire volume providing the structure can be held in such a manner as to permit use either manually or by means of fixtures or attachments. Accordingly, a specific object of the invention resides in providing a surface for a cellular ceramic abrading article, which the operator can grasp manually Without injury from the sharp edges of the broken cell walls, or which can be held by means of fixtures or attachments without breaking away the structure and diminishing the cross section.
Additional objects, advantages and features of the invention will be apparent from the following description, the appended claims and the accompanying drawings.
Referring further to the drawings, wherein a preferred embodiment only of the invention is shown:
Fig. l is a perspective view of an abrading article in block form incorporating the present invention and showing one end, side and bottom thereof;
Fig. 2 is a vertical sectional view through one end of an abrading article, such as shown in Fig. 1, on a work piece;
Fig. 3 is a partial, vertical sectional view of a corner portion of the abrading article of Fig. 2 illustrating its appearance after considerable use and the action of the fringe in collecting and holding debris and cuttings under the Work surface; and
Fig. 4 is a perspective view illustrating how an abrading article of the type shown in Fig. 1 is applied to a work piece by the operator.
In the following specification and in the accompanying drawings a specific embodiment of the invention is disclosed and this embodiment is described in detail. However, it is to be understood nevertheless that the primary purpose of illustrating the invention by reference to a specific form thereof and by the employment of detailed language herein is to facilitate an understanding of the principles underlying the invention, and that the scope of the invention is not intended to be limited thereby.
Fig. 1 discloses an abrading article formed from a cellular ceramic structure, indicated generally at 10, such as described in the patents previously referred to herein. This structure 10, which is in the form of a rectangular block, has substantially vertically extending and oposite ly disposed sides and end walls 11 and 12. The top surface of the block shown is indicated at 14 and the bottom, which is designated as the work surface, is indicated at 15. It is to be understood that the abrading article may be formed into any other desired shape and that the work areas may be contoured to provide an abrasive surface corresponding to the shape of the article to be finished.
In the preferred form of the invention, the abrading article is coated with a reinforcing substance indicated generally at 16. Referring to Fig. l, for example, the structure would be coated on all surfaces except the Work surface 15 which would remain free of the coating. it is to be understood, however, that for the purposes of this invention it is immaterial whether the abrading article, whatever shape it may be, is coated completely and then the coating removed from an. area to expose a work surface or whether the work surface is not coated at all when the coating is applied to the remaining surintegral part of the cellular structure through-surface impregnation.
It issufficient, however, if the coating when applied adheres to the cellular structure, either. by chemicalormechanical adhesion, with sufficient tenacity that ordinary handling-will notcause-partingi between the coated surfaceand the coating. The: coating 16 is applied soas topro'vide. sufiicient thickness to cover protruding parts of. shattered and broken cell walls at the surface ofthe structure.
The coating providedsis tough enough and has sufficient adherencev to remainintact and provide an edge fringe about the uncoatedworking surface, as indicated at 2% in the drawings as the'work surface is worn away during abrading operations. In operation, the fringe formsabouttheworking surface. 15 as shown most clearly in Figs. 2, 3 and 4. -This fringevaries from a starting length of about inch and may develop to a length of approximately /8 inch as the work surface of the structure wears away during the abrading operations. This fringe provides for keeping debris from the work surface and cuttings from the work. piece 22 under the work surface, as indicated at 23. in Figs. 2 and 3, where it serves as an eifective cutting medium. Thus, the action of this coating fringe is to prevent the escape of broken cell wall debris out from under the work surfaceiS and to keep such debris and cuttingsfrom the work piece 22 under the work surface 15. The action'of the-fringe may be likened to that of a broom as .it sweeps around the edges of the work surface.
Anumber of coatings havebeen'found to be: satisfactory for the purposes of this invention; for example, and among others,rubber.base paints, plastic coatings, natural rubber emulsions, many oil-base paints and synthetics. However, a preferred coatingwhichnis very suitable comprises astabilized. dispersion of a copolymer of styrene and butadienethaving-.aniodinenumberof about 140. In thedispersedphase,..this.coating1 is composed of microscopic-particles of. solid. styrene-butadiene copolymer, the particles being approximately-0.2 micron in diameter. The particles coalesce -.as the water evaporates and form a continuous, colorless film having a slight opacity. This coating can also be pigmented and otherwise compounded with 'thickeners and common paint ingredients before applicationto'the cellular structure if desired. The coatings may 'betre'ated with. deodorants or odor producing additives such as cedar or pine" oil, which will be released'or exposed to volatilization as 'the abrading-article is worn. These additives are desirable where the cellular ceramic structure :used'is one con parent that in practice a cellular ceramic structure is fabricated to the approx-imatecr exact shape desired to be used as an abrading article or tool. This structure 'is thenl coated, leaving one surface "thereof 'free of'coating or thereafter removing the coating from an areapreviously covered to expose a work surface. Thestructure 'is then dried or otherwise treated according to'common practice to stabilize the coating so as to" permit handling and use.
-By-covering and supportingshattered and broken cell walls, the coating keeps these surface "fragments from being further :bro'ken' and -"separated-fromthe structure during ordinary handling *and use. The coating also-permitshandling the structure without tearing. and. abrading the skin of the operators hands, as well as making it possible to utilize cellular ceramic structures of greater fragility and hence greater potential abrading ability than would be possible without the coating. Coating also prevents the wear, handling disintegration and clipping from the cutting tool as itleaves or enters the structure when fabricating the abrading article to a desired shape, which uncoated cellular ceramic structures are subject to.
The coating fringe which developes, about the work surface as the-structure wears away 'during abrading operations, keeps the debris and cuttings tunder ,the work surface and on. fiat work. pieces, provides for approximately double theam'ount of abrasion obtained from an uncoated structure under comparable conditions. The cushioning effect and support given to the structure by the coating also contributes to the work life of the abrading article by" permitting the strikingrof: an edge to clean .a.clogged work surface 1 by :jarringwdebris and: cuttings 20;
While the invention disclosed hereinlis of :primary importance in 'the'applicationthereof to abrasive articles formed from cellularceramic structures, :it is to be-understood that the; principles off the invention canabeapplied to otherarticles and devices. 'Applicationof the invention to other types, of structures. can'aiso be readily effected by those skilled inthe art to'which this invention relates.
PHaving .;thus :describedwthe invention,-.what is claimed as newv andcde'siredxto' be securedabyt Letters Patent is: 1. An 'abrading' article formed: from a-fragile multicellular ceramic-structure coated with-a compound comprising a stabilized dispersion of a. copolymer of styrene and butadiene.
2. A coating for a fragile multi-cellular ceramic abrading structure comprising. a" flexible coating. substance adhering to the outersurface thereof which asthe ceramic structure wears devel'opes. a'fringe surrounding a work surface producedironz'said.abrading. article, said fringe projecting from each edge'ofthe'work. surfaceand-providing for retaining'particlestbroken'from said ceramic structure 'in contact with' the work surface.
3. An-.abrading article formed from a fragilem'ulticellular ceramic structure having alwork surface andhav- :ing a flexible coating: reinforcing :the .outer surface of said abradingv article adjacent .tosaid work' surface and forming .aafringe-qaround thezedge of :the-wo'rk surface,
whereby debris from the wearing away of the work sur face is collected and held'incontact with the work surface by said fringe 5. In combination,.a cellular ceramic block structure .havinga plurality'of sides, a flexible coating adhered to some but not to all of saidsides andzcomposed-of a materialwhich abrades moreslowly than the ceramicstructureand which as.the:ceramic structure Wearsforms a flexible fringe which holds 'brokenparticles'of the ceramic structure and other debris within :t-heconfines of said fringe.
References Cited in'the file of this patent UNITED STATES PATENTS 155,461 Ott '.'Sept. 29, i874 1,901,891- Bartholomew Mar. 2], 1933 2,140,650 Quick et al .J Dec. 20,1938