US 3900393 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
United States Patent 1 1 1 1 3,900,393 Wilson Aug. 19, 1975 1 RUBBER GROMMET ARRAY FOR SIZING 3.143.733 5/1964 Rose 209/393 SCREENS 3,273,745 9/1966 Stec 3,624,867 l2/l97l Reynolds 29/45l X [75} Inventor: Earl D. Wilson, Lodi, Calif FOREIGN PATENTS OR APPLICATIONS 1731 Assignee: Randtron, Menlo Park, Calif.
108,053 8/1939 Australia 209/397  Filed: NOV. 5, 1973 l,00l,l66 8/l965 United Kingdom 209/399 121] App], Nd: 413,029
Primary ExaminerRobert Halper Attorney, Agent, or Firm-Roger B. Webster  US. Cl 209/399; 210/498  B07B 1/46 158] Field of Search 209/397, 399, 392; [571 ABSTRACT 210/498; 29/451. 45 A rubber grommet array-for a power-actuated vibratory-type sizing screen which includes an inclined bed l l References Cited plate having a multiplicity of holes UNITED STATES PATENTS therein-comprised of grommets individually engaged 118385 6/1929 Sherwood 209/397 in such holes to define therein a wear-resistant lining, 2,896,889 7/1959 Hershberger 29/453 x and Said grommets 11$ 50 engaged tOgethar Presenting 2,964,187 12/1964) Riedel 0. 209/399 X a wear-resistant facing on the bed plate. 3042206 7/1962 Olender 4 209/395 3,090,: 15 5/1903 Curr 29/453 x 4 Clams 7 Drawmg F'gures Z//' may RUBBER GROMMET ARRAY FOR SIZING SCREENS BACKGROUND OF THE INVENTION Powcractuated vibratory-typc sizing screenssuch as those employed to size sand, gravel, and rockcommonly include an inclined metallic bed plate having a multiplicity of material-sizing holes therein; the abrasive action of the material passing over the bed plate, and certain of the material through the holes, not only undesirably enlarging such holes but also causing substantial surface wear on the bed plate generally. The present invention was conceived in a successful effort to overcome such wear and tear on the perforate bed plate.
SUMMARY OF THE INVENTION The present invention provides, as a major object, a rubber grommet array-for a power-actuated vibratory-type sizing screen which includes an inclined bed plate having a multiplicity of holes therein-comprised of grommets individually engaged in such holes to define therein a wear-resistant lining, and said grommets as so engaged together presenting a wear-resistant fac ing on the bed plate.
The present invention provides, as another major object. a rubber grommet array wherein, in one embodiment, numbers of the grommets are initially integrally related in strip form with a plurality of such strips edgemated, and, in another embodiment, the grommets are initially separate and edge-mated with adjacent grommets. With either embodiment the holes in the bed plate are lined, and the bed plate faced, with rubber, thus effectively providing the desired wear-resistance when the sizing screen is in operation.
The present invention provides, as a further object, a rubber grommet array, for a sizing screen, which is designed for ease and economy of manufacture.
The present invention provides, as a still further object, a practical, reliable, and durable rubber grommet array, for a sizing screen, and one which is exceedingly effective for the purpose for which it is designed.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat diagrammatic, perspective view of a sizing screen embodying the grommet array of the present invention.
FIG. 2 is an enlarged, fragmentary plan view of the assembly of the bed plate with grommets, in strip form, thereon; the strips being partially broken away.
FIG. 3 is a transverse sectional elevation taken substantially on line 33 of FIG. 2.
FIG. 4 is a somewhat diagrammatic, fragmentary perspective view, partially exploded, of another embodiment of the grommet array.
FIG. 5 is a plan view of one of the grommets of the array shown in FIG. 4.
FIG. 6 is a transverse sectional elevation of such grommet; the view being taken substantially on line 66 of FIG. 5.
FIG. 7 is a view similar to FIG. 5, but shows the grommet with a substantially square hole.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the drawings and to the characters of reference marked thereon, and at present to the embodiment shown in FIGS. I 3, inclusive, a sizing screen, indicated generally at 1, includes a perforate bed plate 2, upstanding longitudinal sides 3, and longitudinal guards 4 which slope downwardly and inwardly from the upper portion of the sides 3. The sizing screen 1, which inclines from its receiving to its discharge end, is supported, and longitudinally oscillated or vibrated, by suitable mechanism here shown only in part, as at 5. The above structure of the sizing screen 1 is substantially conventional, and the present invention provides-in combination with the bed plate-a rubber grommet array as follows:
The bed plate 2 is initially formed with a multiplicity of holes 6 arranged in transverse rows wherein such holes are equally spaced; such rows of holes being parallel and equally spaced lengthwise of said bed plate. The holes 6 are of a diameter somewhat greater than the ultimate mesh size desired; this in order to accommodate the rubber lining of such holes 6 by the grommet array, and which comprisesin the FIGS. 1 3 embodimentrows of rubber grommets 7 initially integrally related in flat-faced strip form; the strips-which are rectangular but elongated-being indicated at 8.
The grommets 7 of each strip 8-corresponding in number and spacing to a row of the holes 6 in the bed plate-are removably snap-engaged, from above, in related holes 6. More particularly, the grommets 7 each include a depending neck 9 of a greater outside diameter than that of the related hole 6, and such neck is formed with a circumferential groove 10 which receives the corresponding portion of the bed plate 2 when the grommet 7 (i.e., the neck 9) is inserted from above and snap-engaged in such hole 6. In order to facilitate such insertion of the neck 9 in hole 6, the neck is tapered downwardly, as at 11, below the groove 10.
With the grommets 7 of each strip 8 so engaged in the related holes 6 of a row thereof, the strip providesover such rowa rubber facing on the bed plate 2. The strips 8 are dimensioned so that they edge-mate and define an unbroken facing on such bed plate 2, i.e. on the bed plate at each side of a central, longitudinally extending filler strip 12 which overlies a portion of the bed plate which contains no holes. Also, the facing on the bed plate provided by the grommet strips 8 is bordered by longitudinal side strips 13. The strips 12 and 13 are secured to the bed plate 2 in any suitable manner.
The grommets 7, of each strip 8, have materialpassage holes 14 which are substantially rectangular in plan, and such holes 14 progressively increase in size in a downward direction whereby to assure free flow therethrough of the material being sized.
With the bed plate 2 fitted with the rubber grommet strips 8, the sizing screen 1 has a much longer working life without repair than with a conventional metallic bed plate; the grommets 7 lining the bed plate holes 6, and the strips 8 facing said bed plate, with a material which is elastic or resilient and thus most resistant to abrasive wear and tear.
In the course of time, however, replacement of the grommet strips 8 will be necessary, and this is readily accomplished by merely peeling such strips from the bed plate, and which extractsbecause of their resiliencythe grommets 7 from the bed plate holes 6. Thereafter, new strips 8 are applied to the bed plate by snap-engaging the grommets into the related bed plate holes 6. This is a removal and replacement operation which can be readily accomplished by hand.
Turning now to the embodiment of the invention shown in FIGS. 4 6, inclusive. the bed plate of the siring screen is indicated at 15, andagain-is formed with a multiplicity of holes 16 arranged in transverse rows wherein such holes 16 are equally spaced: the rows of holes 16 being parallel and equally spaced lengthwise of said bed plate 15.
In this embodiment, the individual grommets 17 are separate, flat-faced, and of regular hexagonal form in plan; such grommets being of identical form and size.
Each of the grommets l7 includes-as in the embodiment of FIGS. 1 3, inclusive, and for like purposea depending circular neck 18 having a circumferential groove 19 therein, and with the neck tapered, as at 20, below the groove. Also, as before, the material-passage hole 21 (here circular) in each grommet progessively increases in size in a downward direction.
When the grommets 17 are snap-engaged on the bed plate with the necks 18 projecting downwardly through and rubber-lining the holes 16 in the latter, the grommets 17 are set to matchingly edge-engage and define a rubber facing on said bed plate, except at its borders, and where such facing isin effect-notched. The borders are, therefore, completed, in matching relation, by toothed border strips 22, one of which is shown in H0. 4', each border strip being adapted to be secured to the bed plate 15 by suitable means, and of which a bolt 23 is exemplary.
With the bed plate 15 provided with individual, snapengaged, edge-matching grommets 17, the holes 16 are effectively rubber-lined, and such bed plate is desirably rubber surfaced; both for the advantages hereinbefore described, i.e., long wearing life and yet with the grommets readily removable and replaceable when necessary.
The grommet 24, shown in H0. 7, is substantially the same as the grommets 17 of FIGS. 4 6, inclusive, except that the material-passage hole 25 is substantially rectangular in planjust as the grommets 7 shown in FIGS. 1 3, inclusive. in all embodiments, the materialpassage holes in the grommets may be either circular or substantially rectangular as working conditions, and the kind of material being screened, may require.
The term rubber" as used herein shall be deemed to embrace natural rubber as well as synthetic rubber, including elastomers.
While here disclosed on a power-actuated, vibratorytype sizing screen, the invention can also be used on stationary, and rotary trommel, sizing screens.
From the foregoing description it will be readily seen that there has been produced such a rubber grommet array, for a sizing screen, as substantially fulfills the objects of the invention as set forth herein While this specification sets forth in detail the present and preferred construction of the rubber grommet array, for a sizing screen, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention as defined by the appended claims.
1. A rubber grommet array for a sizing screen which comprises a bed plate having a multiplicity of holes therein, and grommets individually engaged in such holes to define therein a wear-resistant lining, and the grommets together providing a wear-resistant facing on the bed plate; characterized by each rubber grommet being of onepiece and removably snap-engaged directly in the related hole in the bed plate and including a depending neck having an outside diameter greater than the inside diameter of said related bed plate hole, there being a circumferential groove in said neck and the latter tapering downwardly below the groove whereby to facilitate entry of the neck into such related hole and reception of the corresponding portion of the bed plate in such groove upon said snap-engagement of the grommet.
2. A rubber grommet array for a sizing screen which comprises a bed plate having a multiplicity of holes therein, and grommets engaged in each of such holes to define therein a wear-resistant lining, and the grommets together providing a continuous wear-resistant facing on the bed plate; characterized by the rubber grommets including depending necks removably snapengaged in related holes in the bed plate, the grommets being integrally formed and mounted in strips, and the mounted strips edge-mating adjacent strips whereby to define such continuous facing on the bed plate when the grommet necks are so snap-engaged.
3. A rubber grommet array, as in claim 2, for a sizing screen wherein the holes in the bed plate are in rows; the grommet necks of each strip corresponding in number and position to the related holes in the corresponding row.
4. A rubber grommet array, as in claim 3, for a sizing screen wherein the rows of holes in the bed plate extend transversely thereof and are in spaced parallel relation; the strips being transverse, of elongated rectangular form, and longitudinally edge-mated.