US 3050764 A
Description (OCR text may contain errors)
Aug. 28, 1962 E. scHMlEDr-:R ETAL 3,050,764
GRINDING AND POLISI-IING MAT Filed March 17, 1959 2 Sheets-Sheet 1 FIG. 8% FIG. 9a. FIG. lOo..
F/cs. 8c. FIG. QC. 3 FIG. lo..
INVENTORS EMIL SCHMIEDER WERNER HAISS BY #MQ/fw@ ATTORNEY.
Aug. 28, 1962 E. scHMlEDER ETAL 3,050,764
GRINDING AND PoLsHING MAT Filed March l?, 1959 2 Sheets-Sheet 2 FIG. 3. FIG. 4. FIG. 5.. FIG.6. FIG.7.
INVENTORS EMIL SCHMIEDER WERNER HAISS ATTORNEY.
Patented Aug. 28, 1962 3,050,764 GRINDING AND POLISmG MAT Emil Schmieder and Werner Haiss, Haslach (Kinzigtal), Germany, assignors to FA. Ernst Hass Eisenund Metall-KG., Haslach (Kinzigtal), Baden, Germany, a corporation of Germany Filed Mar. 17, 1959, Ser. No. 800,005 9 Claims. (Cl. 15-209) The present invention relates to a grinding and polishing mat, which comprises a suitable carrier, as for instance paper, a layer of artiiicial material, or a textile material, to which a layer of steel wool, preferably in the form of a woven work, is glued.
Such grinding and polishing mats may lbe used in the rst place in all such instances where grinding mats or polishing ribbons are used which are made of emery cloth, emery paper or glass paper.
Compared with the mentioned conventional grinding mats and polishing ribbons, the grinding and polishing mat, designed in accordance with the present invention, brings about the advantage that the spaces between the iine cutting organs contained in the steel wool are not filled up with grinding dust and with the removed grinding means and in addition, that the layer of steel wool has a certain inner yielding power and elasticity.
By using grinding and polishing mats in accordance with the present invention, which are applied, for instance, in form of endless ribbons in conventional ribbon grinding machines, appreciable centrifugal forces are experienced at the points of turning direction of said bands, which may lead, among other results, to an undesirable loosening or even removal of the outer steel wool layers, which are only more or less entangled with the lower steel wool layers.
It is, therefore, one object of the present invention to provide a grinding and polishing mat, which applies the steel wool in form of woven or braided Works, whereby always two adjacent steel wool strands cross each other with the result that the outer layers of the crossed strand are retained by the inner -layers of the crossing strand which are directly adjacent thereto, which strands are, thereby, subjected substantially only to a pull in its longitudinal direction.
lt is another object of the present invention, to provide a grinding and polishing mat, wherein the active layer of the grinding and polishing mat formed of steel wool is applied in form of a woven or plait work, which extends over the entire Width of the grinding and polishing band and is plaited of a plurality of steel wool strands.
It is still another object of the present invention, to provide a grinding and polishing mat wherein the active layer is applied in the form of groups of three strands which are joined into narrow plaits, and which are glued in side-byside arrangement in Such a manner that the carrier is completely covered thereby. `Particularly in the latter case, the design of the individual three strand steel wool plaits glued to the carrier is preferably arranged similar to the point of an arrow in the direction of the run of the polishing band, as may be ascertained from FIG. 1 of the drawings, looking towards the working side by a viewer. This arrangement brings about the result that the steel wool bers, which are pressed onto the work piece face to be worked, cut from the plait center pulling in outward direction, so that the steel wool strands which form the plait do not tear in outward direction with the result of a loosening of the plait works; rather the plait works structure is pushed together towards the center line of the plait.
It is yet another object of the present invention, to provide a grinding and polishing mat wherein the rigidity and liie of the steel wool layer glued to a carrier is appreciably increased by an arrangement according to which the steel wool iibers, which are anchored to that carrier by means of a glue layer, do not project in some way uncovered and emerge from the surface of the practically plane layer of the glue without any change in the border line of the surface. if this would be the case, particularly in a comparatively hard layer of glue, the danger would be brought about that the steel wool iibers, which are subjected to a bending moment, crack or break at the point at which they emerge from the glue layer.
It is, therefore, still a further object of the present invention, to provide a grinding and polishing mat wherein the steel wool bers, which are embedded in the glue layer with their lower portion, have still a downwardly tapered sleeve of the glue material on the vborderline between the glue layer and the air for a certain length. This sleevelike covering may be also formed by a second new material layer which is applied after drying of the iirst layer, which second layer may have yielding or elastic characteristics.
In order to provide such sleeve-like or layer covering of the steel wool fibers, it is, for instance, possible to apply to the flat carrier at iirst one glue layer, into which the steel wool is pressed after the steel wool has been treated with a solvent or thinning medium of the glue material.
With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:
FIGURE l is a schematic showing of a steel wool plait;
FIG. 2 is a cross-section of the grinding and polishing mat showing schematically the steel wool iibers at an enlarged scale;
FIG. 3 is a top plan view of a band showing one ernbodiment of applying the plaits to the carrier;
FIGS. 4 to 7 show similar additional embodiments of applying the plaits to the carrier; and
FIGS. 8a, 8b, 8c, 9a, 9b, 9c, 10a, 10b and 10c show three diiierent embodiments of the edge formation of the band, as well as three diiierent embodiments of the carrier.
Referring now to the drawings, and in particular to FIG. 2, the carrier 1 has applied thereto a layer of any suitable glue material 2, which layer of glue material has at least partly embedded therein individual steel wool chips 3. Sleeve-like projections have been formed on said steel wool chips due to the eiiect of the surface tension on the outer substantially plane surface of the still liquid glue layer 2. These sleeve-like projections are tapered down in outward direction so that upon subjecting the steel wool chips to a bending moment, no sharp break can occur, which would happen if said sleeve-like projections would not be present.
In order to prevent the occurrence of so-called shade lines on the goods to be polished, particularly with endless grinding and polishing bands, which are equipped, in accordance with the present invention, with a steel wool plait glued thereon, which shade lines do occur if the borders between two steel wool plaits are disposed on the carrier exactly parallel to the direction of movement of the band, the carrier formed as an endless band has glued thereto a steel wool plait which is of corresponding length and is disposed thread-like with a slight angular deviation from the direction of movement of the band, the beginning and the end of the lsteel wool plait being disposed below the plait portion which forms the directly adjacent thread turn.
For the same purpose, it is possible to dispose the steel wool plaits, which are glued to the endless carrier, in any other manner more or less inclined towards the direction of the run of the grinding and polishing band and for this `purpose the steel wool plaits may be disposed, for instance, in form of serpentine lines or wave lines, whereby the amplitude of the wave line is at least equal to one half of the width of the plait.
For the protection of endless grinding and polishing bands against possibly occurring'edge tears or the like, caused by the strong mechanical wear in band polishing machines, the carrier band may be equipped, in accordance with the present invention, at bath edges with edge protecting means surrounding the steel wool layer. The partial section of the edge of such band is shown in FIGS. 8a, 8b and 8c as being constituted by a cord glued along the carrier edge. FIGS. 9a, 9b and 9c show an L-shaped protecting band and FIGS. 10a, 10b and 10c a flange formation of the carrier band, whereby the anged edge is glued together to the carrier from which it has been bent over.
The grinding and polishing mat, designed in accordance with the present invention, permits of, in contradiction to known conventional non-expandable emery bands, also the polishing of .uneven faces, and for this purpose the carrier lband is formed of an elastic yielding material, which is made possible due to the use of a corresponding elastic glue medium and upon consideration of the use of steel wool plaits which are expandable within certain limits. f
Theexpandability of the carrier may be obtained, for instance, in such a manner that it is formed of a knitted fabric, as shown in FIGS. 8a, 9a and 10a, or of a rubber band, as shown in FIGS. 8b, 9b and 10b, or of a corressponding elastic -sheet of artificial material as shown in FIGS. 8c, 9c and 10c. Since generally an expandability of the endless grinding and polishing band is crosswise direction is found sucient for Vthe intended purpose and an expandability of the endless polishing band in its longitudinal direction could possibly interfere with the proper working on a -band polishing machine, the carrier band which is basically expandable, is equipped with nonelastic cords or the like in parallel arrangement to the direction of its run, whereby only a crosswise expansion between the bands, cords or the like, is made possible.
Since in the endless grinding and polishing bands, in yaccordance with `the present invention, in contradiction to the known emery bands and glass paper bands, the steel Wool chips which function as removing means are not rigidly connected with the carrier, rather only the lower layers of the steel wool chips are rigidly connected with the carrier, the danger is created that in case of a great running speed of the grinding or polishing band the steel wool layer is loosened due to the great centrifugal forces experienced at the point of the turning rollers, or are even removed completely from the carrier. -In order to meet this danger, the band polishing machines using the grinding and polishing bands, in accordance with the present invention, are equipped on the turning rollers with pressureor enclosing belts or the like, which engage from outside the steel'wool layer, whereby a release or removal of the steel wool layer from the carrier band is prevented. i The enclosing belts may extend over the entire width of the grinding or polished band. They may comprise, however, also a plurality of correspondingly narrow individual belts.
In order to exploit the centrifugal forces experienced at the point of the turning rollers carrying the band for the removal of the polishing dust accumulated between theindividual steel wool fibers, the engaging or enclosing belts are formed as grids and comprise, for instance, a plurality of crossed wires or a knitted wire arrangement from stretching metal or the like.
While we have disclosed several embodiments of the present invention, it is to be understood that these embodiments are given by example only and not in a limiting sense, the scope of the present invention being determined by the claims.
1. A grinding and polishing mat, particularly for bandpolishing machines, comprising a carrier and a lcoextensive layer of steel wool secured to one side of said carrier and having a front side and a back side, said layer of steel wool comprising a plurality of at least individual plaits disposed in side-by-side relationship, and a layer of adhesives securing said backside of the steel wool layer to said carrier. Y
2. The grinding and polishing mat, as set forth in claim 1, wherein saidplaits are multistranded.
said plaits are disposed obliquelyfrelative to they longi entire width of said 'carrier band.
4. The grinding and polishing mat, as set tprth inv claim 3, wherein said carrier band has edge protecting means.
5. The grinding and polishing mat, as set forth in claim 1, wherein said plaits ofsaid layer 'of steel Wool have three-strands, and said strandsV are ydisposed adjacent each other.
6. The grinding and polishing mat, as set forth in claim 5, wherein said layer of adhesive has a yielding characteristic after assuming the dry state thereof, and wherein portions of the free surface of said adhesive layer project from and surround said strands of said layer of steel wool, in order to prevent breaking of steel wool fibers under bending stresses.
7. The grinding and polishing mat, as set forthin claim 1, wherein said plaits of' said steel wool layer are disposed along a serpentine line, the amplitude of said serpentine line being at least equal to one half of the width of said plaits.
8. The grinding and polishing mat, as set forth in claim 1, wherein said 'carrier is formed as a carrier band, the latter yielding in cross-wise direction only and having longitudinal, non-elastic threads.
9. The grinding and polishing mat, at set forth in claim 1, wherein said, layer of adhesives has a lower region and an upper region, the latter being softer than said lower region, the' lower portion of said plaits being embodied in said upper region of said layer of adhesives.
References Cited in the le of this patent 'UNITEDv STATES PATENTS 1,602,505y Robbins Oct. 12, 1926 v1,879,083 Casper Sept. 27, 1932 2,160,885 Martin June 6, 1939 2,308,405 Tully Jan. l2, 1943 2,735,721 Ralferty Feb. 21, 1956 2,845,650 Ashley Aug. 5, 1958 l2,854,286 Salick Sept. 30, 1958 FOREIGN PATENTS 744,376 France Jan. 21, 1933V 801,795 France May 23, 1936 1,053,180 France Sept. 30, 1953 3. The grinding and polishing mat, as set forth in clainrfv 1, wherein said carrier is formed as a carrier band and 'y