US1886173A - Screen - Google Patents

Description

J. A. FLlNT Nov. 1,'1932.

SCREEN Filed Jan 9, 1928 2 Sheets-Sheet NG@ A INVENTOR. BY 7% A TTORNEYS.

J. A. FLINT Nov. l, 1932.

SCREEN Filed Jan. 9, 1928 2 Sheets-Sheet 2 Y web@ ATTRNEYS.

'i Patented Nov.v l, 19.32

UNITED s'ra'ras IPA'raN'i OFFICE JAMES A. FLINT, F DENVER, COLORADO, ASSIGNOB T0 THE TRA'YLOB VIBBATOB onPAN, OF DENVER, COLORADO, A CORPORATION OF COLORADO SCREEN Application inea January e, 192s. serial No. 245,298.

This invention relates to screens for use in connection with screening apparatus in which the screen is vibrated at a high frequency for the purpose of screening or separating materials placed thereon or lfed thereover.

The screen forming the subject matter of this invention is particularly adapted for use in connection with electro-magnetic vibratable screening apparatus, in which the screen is vibrated by means of an electric reciprocating motor or motors, to the reciprocating or vibrating velement or elements of which the screen is attached, and by which it is vibrated at a high frequency.

movement thereof, and the wire or cloth then v springs back against the sash, giving an undesirable flapping action which disturbs the true or proper vibration and results in a wearing out of the screen cloth or wire more quickly than it should do.

The object of the invention is to provide an improved construction of screen whereby the screen cloth or wire is securely and tightly held down upon the screen sash or frame, so that such screen cloth or wire will vibrate exactly with the lsash or frame, thereby providing for a true and proper vibration of the screen as a whole, and avoiding undesirably rapid wear of the screen cloth or wire.

The invention is illustrated in di'erent forms thereof in the accompanying drawings, in which:

Figure 1 is a side elevation, partly in section, of one form of screen constructed in accordance with the present invention;

Figure 2 is an end elevation of the screen shown in Figure 1;

Figure 3 is a somewhat enlarged end elevation, with parts in section, of one-half of the screen as shown in Figures 1 and 2, and adapted' for use where the screen cloth is of tine mesh;

Figure 4 is anenlarged end elevation of one-half of a' screen similar to that. shown in Figures 1 and 2, the construction being modi- 55 fied somewhat for use where the screen wire is of large mesh;

Figure 5 is an end elevation of a modified form of the screen frame or sash; and

Figure 6 is a detailed view showing the application of the invention to a double deck screen. V

Referrin firstly to the construction shown in Figures 1, 2 and 3, the screen frame or sash shown therein comprises two parallel side members 1, which are connected to-` gether by means of a plurality of parallel cross ribs 2, the ends of the cross ribs being dovetailed into suitable ,slots 3 formed in the upper edges of the side frame members, and suitably secured in such slots, as by gluing and fastening with wood screws and dowel pins.

It is usual in making such screen frames or sash, to make the upper edges of the vcross ribs straight or horizontal from one side member to the other, and to mount the screen clothA or wire so that it rests upon the horizontal upper surfaces of the cross ribs. This has been found to be undesirable for the reason ao above indicated that the screen cloth or Wire tends during vibration of the sash or frame to move away from the cross ribs and to fly beck into engagement therewith, producing a flapping action which interferes with the proper vibration and causes rapid wearing out of the screen vcloth or wire.

'To avoid this disadvantage, the upper surfaces of the cross ribs are arched, cambered, or curved, as shown at 4 in Figures 2 and 3, 90

Improved means are provided for effecting the stretching or tightening of the screen 1 cloth or wire transversely of the frame or sash over the arched or cambered upper surfaces of the cross ribs 2. The upper edges of the side frame members 1 are cut away or bevelled to provide downwardly and outwardly inclined surfaces as shown clearly in Figures 2 and 3. Bars or stri s 6, preferably co-extensive in length wit the side members l are provided, these bars or strips having the lower surfaces thereof inclined or bevelled n to mate or coact with the inclined or bevelled up r surfaces 5 of-the side members. Prefernily thebars or strips are of triangular cross section as shown, and they are made somewhat narrower than the side members to provide some allowance for different amounts of stretch in the various sizes of Yscreen cloth, as well asfor variation in cutting the width ef the cloth.

When line mesh screen cloth is to be used on the screen, a narrow slot 7 is cut or rabbeted out at'the upper side of each bar or strip 6, and the edge of the screen cloth is inserted in this slot as shown in Figure 3.

Above the bars or strips 6 are provided side boards 8, which are of approximately the same length as' the bars or strips, and may be of substantially the same thickness. These side boards act primarily as bearing members upon the side edges of the screen cloth and the bars or strips 6, to transmit pressure thereto,

but they also serve as guards to keep the ore or other material being treated, on .the screen cloth.

The means for applying ,pressure to the,

side boards 8 and bars 6, comprises a suitable number of clamps 9, for example, twoof such clamps at each side of the screen frame. Each of these clamps is provided with an inwardly extending foot 10 which engages beneath the lower edge of one of the side members 1, such edgev preferably being notched as indicated at 11, Figure 1, to provide a proper bearing for the foot of the clamp. Preferably also the clamps are attached to the side members 1, as by means of bolts 12, passing through such side members and threaded into the clamps. These bolts are not intended to take any strain but simply to hold the clamps in place on the screen frame when the screen cloth is being chan The heads 13 of the clamps are provided with threaded apertures in which are arranged relatively large screws 14, which C5 at their ower ends bear against shoes 15 which rt upon the upper edges of the side boards 8.

It will be seen that with the feet 10 of the clamps bearin upwardly against the lower edges of the si( e members 1, by adjusting the screws 14 downwardly against the shoes 15, pressure will be transmitted downwardly through these shoes and through the side boards 8, to the side edges of the screen cloth and to the bars or strips 6. As the bars or strips rest with their bevelled or inclined surfaces upon the upper bevelled or inclined surfaces of the side members 1, the transmission of the pressure to the bars or strips will result in the forcing of these strips downwardly and outwardly upon the inclined surfaces 5, the two bars or strips moving away from each other transversely of the screen frame. As the side edges of the screen cloth are held securely down on to the bars or strips 6 and within the slots 7 thereof by the side boards 8, the movement of the bars or strips away from each other will result in the transverse stretching or tightening of 'the screen cloth 16, and such screen cloth will be held tightly down upon the arched or cambered upper surfaces 4 of the cross ribs 2.

It will be understood that the clamps are so positioned, and the shoes 15 are of such length that through the medium of the side boards 8 the pressure will be transmitted uniformly to the edges of the screen cloth and to the bars or strips 6, and that the screen cloth is .thereby stretched over the cross ribs 2 uniformly throughout its entire area.

In cases where the screen wire is of large or coarse mesh, it is preferred to use the modified arrangement of bar or stripv shown in Figure 4. In this form the side edges of the wire mesh 17 are bent down around the outer side of the triangular bar or strip 6 and an angle iron member 18 is employed to hold the wire mesh securely to the bar or strip. This angle iron member is substantially co-extensive in length with the bar or vstrip and the member and bar are formed at intervals throughout the lengths thereof with diagonally extending holes to .receive securing or clamping bolts 19. The side boards 8 in this form bear upon the upper surfaces of the angle members 18. The construction and operation are otherwise the same as described with reference to Figures 1 to 3.

Figure 5 illustrates a modified construction of thescreen frame or sash. This constrllction comprises side members lsimilar to ithose reviously described, and cross ribs 20 exten ing between and connected with the side members in a similar manner to that described with reference to the cross ribs 2 of Figures 1 to 3. The upper surfaces of these cross ribs, however, are straight or horizontal, and the cross ribs are each provided with a plurality of notches 21 in the upper part thereof. In the notches of the cross ribs are positioned and suitably secured a plurality of longitudinally extending ribs 22: These longitudinal ribs areof varying helghts 1nwardly from the side edges toward the center of the screen frame, although each rib 1s of the same height throughout its length. These longitudinal ribs -of varying height constitute in effect an arched or cambered supporting means for thescreen cloth or w1re. It will be understood that the screen frameor sash is provided with similar stretching or tightening means to that described 1n connection with the preceding modifications, and that when such stretching or tightening means is operated, the screen cloth or wire will be stretched tightly over and down upon the upper surfaces of the ribs 22 and Will assume the arched or cambered condition indicated by the dotted line 23.

It will be understood from what has been said that a simple and effective stretching or tightening means has been provided for stretching or tightening the screen cloth or wire upon the screen frame or sash, and that due to the provision of the arched or cambered supporting means upon which the screen cloth or wire is stretched, the screen cloth or wire will at all times be held' tightly down against the sash and will vibrate exactly as a unit with the sash during vibratory movement 0f the latter.

It will be understood that the screen frame or sash is mounted in the screening apparatus so that vibratory movement will be imparted thereto to effect the screening or separation of the materials placed upon or fed over the screen cloth. For example, the side members of the sash may be secured, as by means of through bolts, to the reciprocatory or v1- bratory elements of electromagnetic reciproeating or vibrating motors. With the screen cloth or wire stretched and supported in the condition before described there will be no tendency for the cloth or wire to leave the supporting ribs of the screen frame as in the known forms of screen frame or sash, but the cloth or wire will always be held in close engagement with the supporting ribs whereby the undesirable flapping action previously mentioned will be avoided and the screen cloth or wire will have materially longer life as well as providing for a more effective screening or separation of the materials.

The invention may be readily applied to multiple or double deck screens, for example, as shown in Figure 6, in which the side members la of an upper frame or sash coact with the bars or strips 6 of a lower sash in the same manner as the sideboards 8 cooperate with such bars or strips in the single deck screen previously described. The sideboards 8a are then arranged in coacting relation with the bars or strips 6a of the upper screen frame or sash and the clamps 9a are made longer downwardly and outwardly disposed sur-k face on said bar and coacting with the surface on the side member, and means for exerting substantially vertical pressure on said bar adapted to vcause relative movement between said surfaces to force the bar outwardly.

2. In a screening device, a supporting frame including side members, a screen` disposed across said side members, there being an inclined surface at an angle to the screen surface on at least one of said side members,

a bar to which one edge of the screen is secured, there being an inclined surface on said bar coacting with the inclined surface on the side member, and means for exerting substantially vertical pressure on said bar adapted to cause relative movement between said inclined surfaces to force the bar outwardly.

3. In a screening device, a supporting frame including side members, a screen disposed across said side members, there being an inclined surface at an angle to the screen surface on at .least one of said side members,

- ai bar to which one edge of the screen is secured, there being an inclined surface on said bar coacting with the inclined surface on the side member, a board member substantially coexten'sive in length with said bar and coacting therewith and means for exert ing substantially vertical pressure on said board member adapted to cause relative movement between said inclined surfaces to force the bar outwardly.

4. In a. screening device, a supporting frame including side members, a screen disposed across said side members, there being an inclined surface at an angle to the screen surface on at least one of said side members, a bar to which one edge of the screen is secured, there being an inclined surface on said bar coacting with the inclined Surface on the side member, and screw clamps coacting with said side member and said bar and operative to exert substantially vertical pressure on said bar adapted to cause relative movement between said inclined surfaces to force the bar outwardly. l

5. In a screening device, a supporting frame including side members, a screen disposed across said side members, there being an inclined lsurface at an angle to the screen surface on at least one of said side members, a bar to which one edge of the screen is se- RSU cured, there being an inclined surface on said bar coacting with the inclined surface on the side member, a board member substantially coextensive in length with said bar and coactin therewith, shoes engaging the side of said ard member opposite to said bar and screw clamps coacting between said side member and said shoes and operative to apply substantially vertical pressure on said bar adapted to cause relative movement between said inclined surfaces to force the bar outwardly.

In testimony whereof I aix my signature.

JAMES A. FLINT.

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