US2178381A

US2178381A - Abrading device

Info

Publication number: US2178381A
Application number: US204365A
Authority: US
Inventors: Trinkle Carl
Original assignee: BALDWIN CO
Current assignee: BALDWIN Co
Priority date: 1938-04-26
Filing date: 1938-04-26
Publication date: 1939-10-31
Anticipated expiration: 1956-10-31

Description

s. TRINKLE 2178.381

ABRADING mines Filed April 2a, 1938 INVENTOR Patented Oct. 31, 1939 ABRADING D'EVICE Carl Trinkle, Cincinnati, Baldwin Company,

Ohio, assignor to The Cincinnati, Ohio Application April 2s, 1938, Serial No. 204,365 5 Claims. (01.. 51-187) My invention has reference to means relating to abrading methods and more particularly to abrading processes employing liquids with the abrading substances. These wet processes of abrading, so called, are especially advantageous in finishing metals, such for example as stainless steel, aluminum andthe like, and article surfaces precoated with lacquers, varnishes, enamels or the like, to provide them with pleasing decorative appearance. The processes are often carried out by partially enclosing a suitable block or pad in a sheet of abrasive paper, with the abrading surface exposed, and rubbing the article surface with it, periodically dipping the abrasive sheet and its hacking into a liquid such as water or benzine.

The use of a liquid in fine abrasive finishing is advantageous, and in my opinion it acts both as a lubricative cooling agent to prevent local heating of the work and as a'distributant for the abraded particles, to prevent their agglomeration. It also reduces the loading of the abrasive sheet.

As carried out with the usual means for wet abrading, the rubbing of the article surface squeezes the liquid out from under the abrasive sheet and pushes it out of the path of operation. This drying of the work results in chattering or jumping of the abrading device thereon, with a consequent loss of time and annoyance to the operator, requiring frequent replenishment of the liquid. Moreover it reduces the probability of a high class of finishing. Again, during the wet abrading, abraded materials such as a sludge of lacquer or the like accumulates unevenly on the surface of the paper, impairs its action, and is so difiicultly removable that the paper is usually thrown away instead of being salvaged as by scrubbing.

The general objects of my invention are the provision of an abrading'means, structure and process whereby the disadvantages set forth above are obviated, and whereby the work is facilitated and shortened, the materials made to last much longer, and the several advantages attained without cost.

The attainment of these objects and other objects which will be apparent to those skilled in the art onreading this specification, I accomplish by that certan. construction and process of which I shall now set forth certain exemplary embodiments, reference being made, for clearness, to the drawing forming a part hereof. In the drawing, wherein all views are in perspective:

Figure 1 shows anabrasive sheet constructed 55 according to the invention;

Figure 2 represents a pad;

' Figure 3 shows the combination of the sheet of Figure 1 and the pad of Figure 2;

Figure 4 is a view of a holding block;

Figure 5 shows the combination of the block of Figure l and the sheet and pad of Figures 1 and 2, respectively; and

Figure 6 shows a modified'form of sheet construction.

I have made the discovery that if a paper or cloth surfaced with an abrasive suitable for wet abrading processes is perforated at intervals and is used in connection with a polishing block surfaced wlth absorbent substance such as felt, the Whole being dipped into the liquid vehicle, two 1 simultaneous actions occur during the course of the rubbing: First the liquid continues to feed through the perforations in the paper, so as to maintain at all times a film of liquid on the work. Even with highly volatile liquids, the film can be maintained with one dipping usually far longer than necessary to complete the rubbing cycle. Thus chattering or jumping of the rubbing device is prevented, and a superior finish is obtained. Second, at the same time the sludge produced by the rubbing goes into the holes in the abrasive sheet in countercurrent to the liquid, so that all sludge is either collected in these holes or accumulates beyond the edges of the abrasive sheet at the end portions of the rubbing stroke. The efflux of the liquid through the holes does not interfere with the entrance and collection of the sludge in the holes, nor does the liquid tend to spread the sludge over the surface of the abrasive sheet. At the conclusion of the rubbing cycle the surface of the abrasive sheet will be found quite clean; and the abrasive device may be redipped and reused until the abrasive is wholly worn away.

All of these factors tend to shorten the rubbing operation, and make the cutting action much more efficient.

Thus in one form of sheet construction, as in Figure l, a sheet of smooth paper I is coated with finely divided aluminum oxide 2 attached to the sheet by suitable cement, and interspacedin the sheet are a plurality of openings such as the holes 3 for liquid transmissivity. My invention is not limited to any particular abrasive material; hence the term aluminum oxide is to be construed as meaning any suitable abradant, reduced to the required fineness according to the character of the work to be done; similarly, the word paper is to be construed as meaning any sheet comprising a porous liquid-absorbent member and to which an abradant may be attached. In Figure 2 is shown an absorbent pad 4 which may be of felt, cloth, absorbent paper or the like ca.- pable of storing liquid, and in Figure 3 this pad or backing 4 is combined by juxtaposition with the sheet I, with the abradant 2 exposed, to form an abrading device of the invention.

As a convenient means for holding an abrasive sheet, a block 5 (Figure 4) may be of rubber, wood or the like and has slots 6 and 1, one on each side as shown. The edges of the sheet I may be placed in these slots with the pad 4 between the sheet and block, as shown in Figure 5, to form an abrading device operative according to the invention, in which the abrasive sheet may be readily disengageably attached to the absorbent backing 4, 5.

In a modified form of sheet construction, Figure 6, a sheet of cloth 8 is coated with abrasive particles, but in interspaced areas 9 of the cloth the cement for adherence of the coating has been omitted, and in these areas 9 the porosity of the cloth permits transmissivity of liquid.

In practicing my invention, I have found that the best finishes on article surfaces are obtained when the abrasive particles of the abrasive sheet are not larger than will pass through a 240 mesh screen. Moreover it is not advantageous to employ liquid transmissive areas in the sheet, of less than an equivalent hole diameter of inch, nor to provide a total liquid transmissive area in excess of per cent. of the sheet area.

The present device may be modified in form and construction within the spirit of the invention. It may be of various sizes suitable for machine or manual use. Accordingly the scope of the invention is pointed out in the appended claims and having thus described my invention, I claim:

1. A rubbing pad for wet abrasive finishing an abrasive sheet having perforations therethrough and backed by said member so that when wetted said member causes liquid to feed through said perforations in said sheet when said pad is applied as an abrasive means in a wet abrasive finishing operation.

2. A rubbing pad for wet abrasive finishing comprising a porous liquid-absorbent member and an abrasive sheet having areas transmissive of liquid therethrough and backed by said member so that when wetted said member causes liquid to feed through said perforations in said sheet when said pad is applied as an abrasive means in a wet abrasive finishing operation.

3. A rubbing pad for wet abrasive finishing comprising a porous liquid-absorbent member and a sheet of suitable paper having perforations therethrough and having a coating thereon of suitable abrasive particles cemented thereto of a size that will pass through a 240 mesh screen, said sheet being backed by said member so that when wetted said member causes liquid to feed through said perforations in said sheet when said pad is applied as an abrasive means in a wet abrasive finishing operation.

4. A method of wet abrasive finishing which comprises cementing a coating of suitable abrasive particles to a suitable sheet as a base and providing areas transmissive of liquid there through at intervals in said coating and said sheet, backing said sheet with a porous liquidabsorbent member, Wetting said member with a suitable liquid, and rubbing a surface to be finished by wet abrasion with said sheet as backed by said member.

5. A method of wet abrasive finishing which comprises cementing to a suitable sheet of paper a coating of suitable abrasive particles of a size that will pass through a 240 mesh screen and providing perforations at intervals in said coating and said sheet, backing said sheet with a porous liquid-absorbent member, wetting said member with a suitable liquid, and rubbing a surface to be finished by wet abrasion with said sheet as backed by said member.

CARL TRINKLE.