US 3021649 A
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Description (OCR text may contain errors)
Feb. 20, 1962 R. ROBBINS PERFORATED ABRASIVE FACED SCRUBBING PAD Filed. Feb. 4, 1959 INVENTOR. A341 PH Rama/N5 in M fates Foam Rubber Corp., New York, N.Y., a corporation of New York Filed Feb. 4, 1959, Ser. No. 791,174 -1 Claim. (Cl. 51-485) This invention relates to an improved cleaning pad having an abrasive coating on at least one face thereof.
Abrasive faced cleaning pads have come into wide use for many purposes in recent years as a substitute for steel wool and similar cleaning abrasives. One such pad in common use today consists of a rubber or plastic foam backing, having a coating of silicon carbide fixed to one face thereof. These pads have been generally effective but they are not completely efiicient because the application of the abrasive to the face of the backing material produces a zone at which the two are joined through which liquid will not pass with the result that the surface being worked on receives only the liquid which is applied thereto by the abrasive face of the pad, or which is otherwise applied.
This invention, therefore, contemplates an abrasive pad having liquid passages extending to the abrasive face such that all parts of the surface of the article being Worked on may be supplied with the passage of liquid through the abrasive face of the pad at a plurality of contiguous points within the area of the abrasive surface.
It is a further and more specific object of the invention to provide an abrasive pad having a flexible backing of liquid absorbing material, which backing, in effect, comprises a liquid holding reservoir, in combination with means for conducting liquid from the absorbent backing through a generally liquid impervious zone, and to the abrasive face of the pad.
It is the most specific object of the invention to provide an abrasive pad having a flexible backing of rubber or plastic foam which comprises a liquid absorbing and holding reservoir, in combination with a plurality of con tiguous liquid passages extending through the foam base and through the abrasive facing on the pad such that liquid held in the absorbent base can be discharged through the passages to the area of the work being processed by the abrasive face of the pad.
These and other objects and advantages of the invention will become clear upon perusal of the following detailed description when read in light of the drawing forming a part hereof, and in which drawing like reference numerals indicate like parts, and in which:
FIG. 1 is a perspective view of a preferred form of the improved cleaning pad comprising the invention;
FIG. 2 is a sectional view on line 2-2 of FIG. 1;
FIG. 3 is a sectional view of a modified form of the cleaning pad herein; and
FIG. 4 is a sectional view of still a further modification of the cleaning pad herein.
FIGS. 1 and 2 of the drawing disclose a cleaning pad having a backing member 10 and a coating of abrasive material 12 fixed to one face thereof, while that form of the invention shown in FIG. 3 discloses a modification in which a backing member 14 has a layer of abrasive material 16 and 18 afiixed to the opposite faces thereof. In the pads of FIGS. 1-3 liquid passages 22 and 24 extend through the backing member and through the coating of abrasive material, while that form of the invention shown in FIG. 4 illustrates a structure in which liquid passages are formed in the coating of abrasive only.
atent lice 3,021,649 Fatented Feb. 20, 1952 As stated above, abrasive faced cleaning pads consisting of a backing member and a coating of abrasive material are well known. In the formation of such pads and specifically in the application of the abrasive coating thereon, there is formed a coating on the face of the backing material which is impervious to the passage of liquids. This impervious coating, depending on the manner in which the abrasive material is applied, may comprise the entire abrasive layer or at least an impervious zone 20 at the juncture of the abrasive coating 12 and the backing material 10, as indicated in FIGS. 1 and 2. The impervious surface of the pad resulting from the application of the abrasive materially reduces the efiiciency of the pads because liquids useful in the cleaning or abrading action cannot pass through the pad and must, therefore, be separately applied to the 'surface being operated on. The pad is, therefore, made much more efficient by forming a plurality of liquid ducts 22 which extend through the abrasive facing 12 and through any liquid-resistant zones, such as the juncture 20 between the backing member 10 and the abrasive face 12.
The utility of the passages 22 is particularly marked when the backing member 10 is absorbent and will retain a substantial quantity of liquid which, during use, is expelled through the passages 22 to the area of the abrasive pad face.
- In a preferred form, the backing 10 consists of a rubber or plastic foam, which is not only absorbent, but is also flexible. The abrasive element of the pad face 12 may be selected from a Wide variety of abrasives suitable for the purpose and among those successfully used has been silicon carbide. The abrasive coating can be formed on the backing material in a number of Ways, such as by first mixing theabrasive particles with a waterproof glue or cement and then spreading the mixture on the backing 10. Alternately, the backing material 16 may be coated with a waterproof cement or glue and the abrasive particles may then be sprinkled over the coated surface while the coating is still wet.
When the abrasive coating is formed by first mixing the abrasive particles with a glue or a cement, the entire abrasive layer appears to constitute a barrier to the passage of liquids. In the case where the backing 10 is first coated with a glue or cement there is apt to be formed a barrier zone, such as the zone 20, which comprises the principal part of the adhesive coating. In cases wherein the backing material 10 is in the form of rubber or plastic foam, the adhesive material by which the abrasive particles are fixed to the face of the backing, may constitute a mild solvent for the foam backing and in such cases, the liquid impervious zone 2% will again be formed.
After the adhesive coating 12 has been fixed to the backing 10, this operation preferably being performed on relatively large sheets of the backing material, the sheets so coated are perforated in any suitable manner to formfhe liquid passages 22 therein. The orientation of the hquid passages 22 in respect to each other is of importance only to the extent that they be provided in sufficient numbers to permit the relatively free passage of liquid from the backing 10 to the face of the abrasive coating 12, such that when pressure is applied to the backing, liquid absorbed within the backing will flow through the passages 22 onto the work area at the face of the pad.
The modified form of the invention illustrated in FIG. 3 in all respects may be the same as that shown in FIGS. 1 and 2, with the exception that a pair of abrasive faces 16 and 18 are employed. It will be noted that when both faces of the backing material 14 are provided with an abrasive coating, the liquid passages 24 therein serve the specially useful purpose not only of providing for the egress of liquid to the face of the pad which is being used, but they also control the ingress of liquid into the absorbent backing material 14 which is enclosed between the abrasive faces 16 and 18.
As indicated, the preferred embodiment of the invention utilizes a flexible, absorbent backing material, such as rubber or plastic foam, but certain advantages of the invention are realized even if the backing material does not absorb substantial amounts of liquid and even though it is of a rigid nature.
In FIGS. 1 through 3, the liquid passages extend not only through the liquid impervious zone at the face of the pads but also through the body of the backing material on which the abrasive faces are formed. This structure is a convenient one particularly when the abra sive coatings are formed directly on the backing material and, indeed, the through-liquid passages assist in channeling the treating liquid to the face of the pad so formed. It should be understood, however, that the important feature of the invention is the formation of the contiguous passages through the portions of the structure which do not ordinarily pass liquid readily. Therefore, particularly in cases wherein the backing material is an absorbent material such as rubber or plastic foam into which andthrough which liquids pass with ease, the liquid passages need be formed only in the liquid barrier at the face of the backing material. A form of pad having liquid passages through the abrasive face of the pad only is shown in FIG. 4, wherein the base material 26 is a sheet of rubber or plastic foam to which a preformed layer of abrasive material 28 has been affixed. The pad illustrated in FIG. 4 can be made by securing an abrasive sheet 30 to the face of the backing material. In such event, the liquid passages 32 need extend only through the abrasive material and its carrier sheet 30, such passages being formed conveniently before the abrasive-carrying sheet is affixed to absorbent backing material 26.
While the fundamentally novel features of the invention have been illustrated and described in connection with specific embodiments of the invention, it is believed that these embodiments will enable others skilled in the art to apply the principles of the invention in forms departing from the exemplary embodiments herein, and such departures are contemplated by the claim.
A unitary abrasive cleaning pad comprising a flexible body of liquid absorbent backing material, a substantially homogeneous coating layer on and contiguous with a surface of said body and adherent thereto, said homogeneous coating layer consisting essentially of a waterimmiscible adhesive which is solidified in the final article and which exists in said coating layer as a flexible continuous phase and a solid abrasive material in fine granular form existing in said coating layer as a discontinuous phase, and a plurality of apertures extending through said coating layer and through said body of backing material, whereby an aqueous liquid may pass into said absorbent body of backing material and from said body of absorbent backing material through said apertures to the face of said coating layer. 1
References Cited in the tile of this patent UNITED STATES PATENTS 1,690,960 Yamanaka -n Nov. 6, 1928 2,178,381 Trinkle Oct. 31, 1939 2,268,403 Kingman Dec. 30, 1941 2,650,158 Eastman Aug. 25, 1953 2,780,533 Hurst Feb. 5, 1957 2,804,728 Politzer et a1. Sept. 3, 1957 2,838,890 McIntyre June 17, 1958 2,880,439 Schwartz Apr. 7, 1959 2,935,823 Heymes May 10, 1960 FOREIGN PATENTS 208,389 Great Britain Dec. 27, 1922