Claims:WE CLAIM:
1. A vibrating screen (1) comprises a swing frame assembly (2) having side plates (3, 3’) connected by one or more deck frames (4) is elastically mounted on a screen frame (14) with one or more compression springs (11) and carries an oscillation generator (12) driven by a drive system, characterized in that the vibrating screen (1) comprising one or more moveable supports (5, 5’,5’’) rigidly fitted to the side plates (3, 3’) of the swing frame assembly (2); one or more fixed supports (6, 6’, 6’’) arranged in parallel in between the moveable supports (5, 5’, 5’’) at pre-determined distance in the direction of flow of material; and one or more clamping angles (7, 7') fixed to the fixed supports (6, 6’, 6’’) and the moveable supports (5, 5’, 5’) in length wise direction, the clamping angles (7, 7') are provided with one or more threaded holes (7a) for fixing a flexible sieve mat (8) of pre-defined length,
wherein ends of the fixed supports (6, 6’, 6’’) extend through holes (3a, 3a’) provided on the side plates (3, 3’) and detachably mounted on longitudinally arranged bearing beam (10) and each pair of moveable supports (5, 5’, 5’’) and fixed supports (6, 6’, 6’’) are connected by the flexible sieve mat (8),
wherein when the swing frame assembly (2) oscillates by the oscillation generator (12), the moveable supports (5, 5’, 5’’) makes oscillatory movement with reference to the axis of the fixed supports (6’, 6, 6’’) in addition to the vibratory movement generated by the swing frame assembly (2), and
wherein the oscillatory movement of the moveable supports (5, 5, 5’’) results in dynamically tensioning and relaxing of the flexible sieve mat (8), and produces enhanced acceleration to the material present on the surface of the flexible sieve mat (8).
2. The vibrating screen as claimed in claim 1, wherein the flexible sieve mat (8) is in the form of strip of pre-determined dimensions and made of polymeric material and provided with one or more fixing holes (8a).

3. The vibrating screen as claimed in claims 1 and 2, wherein the flexible sieve mat (8) is made of polyurethane.

4. The vibrating screen as claimed in anyone of claims 1 to 3, wherein the fixing holes (8a) of the flexible sieve mat (8) is oblong in shape and arranged in the flow direction of material.

5. The vibrating screen as claimed in anyone of claims 1 to 4, wherein effective length of the flexible sieve mat (8) between a pair of the fixed supports ( 6, 6’, 6’’) and moveable supports (5, 5’, 5’’) is adjustable.

6. The vibrating screen as claimed in anyone of claims 1 to 5, wherein the flexible sieve mat (8) is fitted to the clamping angles (7, 7') fixed to the fixed supports (6, 6’, 6’’) and the moveable supports (5, 5’, 5’) with one or more clamping strips (9) using one or more fasteners.
, Description:FIELD OF INVENTION
The present invention relates to a vibrating screen used in sand manufacturing system. More particularly the present invention relates to a vibrating screen with flexible sieve mat for segregating materials according to the size after crushing during sand manufacturing process. The flexible sieve mat is made of elastomeric material which stretches between a fixed member and a moveable member for more effective screening of the aggregates.

DESCRIPTION OF PRIOR ART
Screening is an important step in the processing of bulk materials for classification of the aggregates and vibrating screen is one of such classifiers widely in use. The vibrating screen known in the art works based on the principle of linear displacement of the materials produced due to unbalance forces generated by two unbalance mass rotating in opposite direction of a rotary oscillator. The vibrating screens are basically used to separate a mix of particles into two or more groups depending on size. The vibrating screens are available as single deck or multi decks depending on the products produced by the plant.

The vibrating screen normally comprises a support provided with two side plates which are connected in their end regions by transverse bearing beams. The support is generally supported on springs and carries an oscillation generator which may be, for example, a rotary oscillator. The bearing beams also supports the screens of pre-determined openings used to classify two fractions of a feed material. The material fed to the screen moves along the screen due to gravity and screen motion. While the coarse material passes over the screen the finer material passes through the openings. The selection of the screen mesh depend on factors such as the materials to be screened, whether the material is dry and free flowing or is moist and sticky, particular size of the material to be screened, shape of the material etc.

In the known vibrating screens, the screening of the material takes place due to the vibration and gravitational effect. Nowadays there is a growing demand for effective classification of the aggregates which poses an insurmountable challenge to most conventional screens. The presence of more and more moisture in the processing material causes the build up in the screens and the screened material passing through the screen openings may become entangled in the screen and more and more clogging of the material resulting in the ineffective performance of the screen.

US 4581132 discloses an apparatus that comprises an oscillatory support comprising two side plates defining transversely aligned window openings at spaced locations along the side plates and first transverse bearing beams extending between the aligned window openings and connecting the side plates. Inertia is imparted to the oscillatory support by two side bearing beams extending along the two side plates and second transverse beams passing through the aligned window openings in the side plates and connecting the side bearing beams. Pairs of spring elements are connected to the side plates of the support at the spaced location, the two side bearing beams being gripped between the spring elements of each pair. Sifting mats are secured between respective ones of the first and second transverse beams. In the above arrangement the performance is likely to deteriorate over a period of time due to the aging of the spring elements that connects the side plates.
It will be advantageous to construct a vibrating screen which will provide more gravitational force to the screen by incorporating a sieve mat which being alternately compressed and stretched in sections in addition to the basic oscillatory movement incorporated to the support by the oscillator.

OBJECTS OF INVENTION
One or more of the problems of the conventional prior art may be overcome by various embodiments of the present invention.

It is the primary object of the present invention to provide a vibrating screen with flexible sieve mat.

It is another object of the present invention, wherein the vibrating screen with flexible sieve mat is positioned in between a pair of fixed support and a moveable support which could be stretched and relaxed to incorporate acceleration on the surface of the sieve mat.

It is another object of the present invention, wherein the flexible sieve mat is made up of material which includes but not limited to elastomeric material.

SUMMARY OF INVENTION
Thus according to the basic aspect of the present invention there is provided a vibrating screen that comprises a swing frame assembly having side plates connected by one or more deck frames is elastically mounted on a screen frame with one or more compression springs and carries an oscillation generator driven by a drive system, characterized in that the vibrating screen comprising one or more moveable supports rigidly fitted to the side plates of the swing frame assembly; one or more fixed supports arranged in parallel in between the moveable supports at pre-determined distance in the direction of flow of material; and one or more clamping angles fixed to the fixed supports and the moveable supports in length wise direction, the clamping angles are provided with one or more threaded holes for fixing a flexible sieve mat of pre-defined length,
wherein ends of the fixed supports extend through holes provided on the side plates and detachably mounted on longitudinally arranged bearing beam and each pair of moveable supports and fixed supports are connected by the flexible sieve mat,
wherein when the swing frame assembly oscillates by the oscillation generator, the moveable supports makes oscillatory movement with reference to the axis of the fixed supports in addition to the vibratory movement generated by the swing frame assembly, and
wherein the oscillatory movement of the moveable supports results in dynamically tensioning and relaxing of the flexible sieve mat, and produces enhanced acceleration to the material present on the surface of the flexible sieve mat.

It is another aspect of the present invention, wherein the flexible sieve mat is in the form of strip of pre-determined dimensions and made of polymeric material and provided with one or more fixing holes.

It is another aspect of the present invention, wherein the flexible sieve mat is made of polyurethane.
It is another aspect of the present invention, wherein the fixing holes of the flexible sieve mat is oblong in shape and arranged in the flow direction of material.

It is another aspect of the present invention, wherein effective length of the flexible sieve mat between a pair of the fixed supports and moveable supports is adjustable.

It is another aspect of the present invention, wherein the flexible sieve mat is fitted to the clamping angles fixed to the fixed supports and the moveable supports with one or more clamping strips using one or more fasteners.

BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1: of the drawing illustrates the perspective view of the vibrating screen with flexible sieve mat according to the present invention.
Figure 2: of the drawing illustrate the front view of the vibrating screen with flexible sieve mat according to the present invention.
Figure 3: of the drawing illustrate the partial cross sectional top view of the vibrating screen with flexible sieve mat according to the present invention.
Figure 4: of the drawing schematically illustrate the front view of the fixed support and the moveable support of the vibrating screen with flexible sieve mat according to the present invention.
Figure 5: of the drawing schematically illustrate the side view of the fixed support and the moveable support of the vibrating screen with flexible sieve mat according to the present invention.
Figure 6: of the drawing schematically illustrate the flexible sieve mat according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
The present invention as discussed hereinbefore relates to a vibrating screen with flexible sieve mat for segregating materials according to the size after crushing during sand manufacturing process.

Referring to the figures 1 to 6, the vibrating screen (1) that comprises a swing frame assembly (2) having side plates (3, 3’) connected by one or more deck frames (4) as shown in Figure 1 is elastically mounted on a screen frame (14) with one or more compression springs (11) and carries an oscillation generator (12) driven by a drive system; material fed to the vibrating screen (1) moves along the vibrating screen (1) due to gravity and oscillatory motion; while coarse material passes over the vibrating screen (1) the fine material passes through one or more openings, characterized in that said vibrating screen (1) comprising one or more moveable supports (5, 5’,5’’) rigidly fitted to the side plates (3, 3’) of the swing frame assembly (2); one or more fixed supports (6, 6’, 6’’) arranged in parallel in between the moveable supports (5, 5’, 5’’) as shown in Figure 3 at pre-determined distance in the direction of flow of material. Ends of the fixed supports (6, 6’, 6’’) extend through holes (3a, 3a’) on the side plates (3, 3’) and detachably mounted on a bearing beam (10) longitudinally. One or more clamping angles (7, 7') are fixed to the fixed supports (6, 6’, 6’’) and the moveable supports (5, 5’, 5’) in length wise direction as shown in Figures 4 and 5.
The clamping angles (7) are provided with one or more threaded holes (7a) as shown in Figure 4 for fixing a flexible sieve mat (8) of pre-defined length with a clamping strip (9) using one or more fasteners. When the swing frame assembly (2) oscillates by the oscillation generator (12), the moveable supports (5, 5’, 5’’) makes oscillatory movement with reference to the axis of the fixed supports (6’, 6, 6’’) in addition to the vibratory movement generated by the swing frame assembly (2). The oscillatory movement of the moveable supports (5, 5, 5’’) results in dynamically tensioning and relaxing of the flexible sieve mat (8) and produces enhanced acceleration to the material present on the surface of the flexible sieve mat (8). The combination of the enhanced acceleration produced as above along with the acceleration generated by the vibration of the swing frame assembly (2) induced by the oscillation generator (13) results in enhanced acceleration on the surface of the flexible sieve mat (8) which facilitates more effective screening of the materials.

The moveable supports (5, 5’, 5’’) and fixed supports (6’, 6, 6’’) are made up of materials which include but not limited to cylindrical shaped metallic pipes. The clamping angles (7, 7’) are preferably made up of materials which include but not limited to metallic material of pre-determined dimension. The flexible sieve mat (8) is in the form of strip of pre-determined dimension having one or finer pin holes of pre-determined diameter. The flexible sieve mat (8) is made up of elastomeric material which includes but not limited to polyurethane. One or more fixing holes (8a) of the flexible sieve mat (8) as shown in Figure 6 are oblong in shape and arranged in the flow direction of the material. The clamping strip (9) is made up of materials which includes but not limited to sheet metal. The clamping strip (9) is provided with the row of fixing holes arranged at the same pitch distance as that of the fixing holes (8a) arranged on the flexible sieve mat(8).

In one embodiment, the flexible sieve mat (8) is provided with means for snap fixing of the flexible sieve mat (8) with the angle (7) without the fasteners.