US1458111A - Electrically-vibrated screen - Google Patents

Description

June 5, 1923.

T. J. STURTEVANT ELECTRICALLY VIBRATED SCREEN "'2 Sheets-Sheet 2 Filed April 28. 1922 NM N R M M Y 5 o a g 2 M mm M N 2 0 N m M W T N WM mm. m6; 7 B N@ 2 .[ili wmmuli L QQ EN mm mm m? mm m mm mm Jill on. ll A l unrelated o,

ones vans a. srnn'rnvsnr, or ivnnnnsrnr night. COMPANY, or nearest, arassaorznsnrrs, A conrona'rron or MASSACHUSETTS, ASSIGNUR TO STUIWZLF ELECTlEtICALLY-VEERATED SCREEN.

Application filed April 28, $22.

To all to from it may concern 7 Be it known that l, THOMAS J. Sutfn'rnvans, a citizen of the United States, residing at Wellesley, in the county of Norfolk and State of Massachusetts, have invented an Improvement in Electrically Vibrated Screens, of which the following description, in connection with the accompanying draw ings, is a specification, like characters on the drawings representing like parts.

The invention to be hereinafter described relates to separators for grading materials, and more particularly to separators employing one or more screens.

In. order that the meshes of the screen clothing shall be kept open for etficient classification of the materials, it is necessary to provide means for vibrating-the clothing. Various types of vibrating mechanisms have been employed, such, for example, as cams and eccentrics for shaking the screens, at" hammer devices for imparting blows to the screen clothing.

These devices are liable to subject the clothing to severe strains-which stretch the wires of the clothing so as to enlarge the meshes thereof, and thereby prevent uniform classification of the materials. These strains "also tend to cause pockets or local sagging in the clothing, which interfere with proper classification. The severe and vigorous vibration of the clothing by such devices. causes the clothing to tier back and forth along the lines of juncture of the clothing with its supporting frame, thereby weakening the Wires of the clothing and ultimately rupturing the same, so as to necessitate substitution of new clothing therefor.

Une of the purposes of the present invention, therefore, is to provide means for vibrating the screen clothing by causing rapid tremors or pulsations of the clothing throughout the area thereof, so that the clothin is in a continuous state of rapid agi tatiomhut without substantial amplitude of vibration. To accomplish this, electro-magnetic vibrating mechanism is employed in circuit with a source of electricity which is of a character or so controlled that the electromagnetic force is rapidly varied and the armature of the magnet is rapidly agitated or vibrated. The pulsations of the armatnroin turn are transmitted to the screen, and the clothing of the latter is in a highly Serial 150. 557,309.

vibrant state which etl'ectively prevents clogging of the meshes of the clothing, so that the meshes are always kept open for uniform, etiicient classification of the materials.

Heretofore. electromagnetic devices have been employed for vibrating screens, and usually the armature of the magnet is secured to th screen, so that the latter receives vibrations or pulsations corresponding to those of the armature.

On the other hand, in accordance with the present invention, the armature is not connected to the screen, but the screen is supported by the armature independently of positive connection therewith, and the weight of the screen is yieldingly sustained by a spring means which acts on the armature in opposition to the vibrant pull by the armaf duccd by the pulsating current supiereto. The construction is such that on is free "to floaton its vibrant support and without materially deadening the lively vibration produced by the electromagnet.

ilith the aforesaid and other purposes in view, the character of the invention may be best understood by reference to the following description of one good form thereof shown in the accompanying drawings, in which:

Fig. 1 is a vertical longitudinal section through a separator embodying the invention;

2 on an enlarged scale is a transverse section taken on line 2-2 of Fig. 1; and

Fig. 3 on an enlarged scale is a section taken on line 3-3 of Fig. 1.

Referring to the drawings, the separator shown therein as one good form of the in vention, comprises a frame 1 supporting a casing in inclined position. This casin comprises a bottom 3, sides 5 and a cover having its upper end connected to the body by hinges 9.

'1 o introduce materials to be graded into this casing, a feed box ll is provided at the upper end of the casing and in communication therewith. The materials are introduced into the feed box at one end. thereof through a neck 13, and are conducted longitudinally of the feed icon by a screw conveyor 15 which may be driven by usual. well.

known means, unnecessary to show herein. The materials fed along the feed box by the conveyor, flow over a distributing plate 17, held in different vertical positions by adjustin screws 19. The materials" flowing over 1: e distributor plate gravitate downward and are directed into the upper end of the casing by a deflecting plate 21. The feed box may be provided with hinged doors 23 and 25 which enable ready access to the parts therein.

A screen or screens may be mounted in the casing, and in the present instance, two screens are employed, one an upper or scalper screen, and the other a'lower or fine screen.

The upper screen comprises screen clothing'27 which may be stretched on a frame having side members 29 connected by end members 31. Intermediate the side members and extending longitudinally of the screen are members 33 which may be suitabl secured to the screen clothing 27.

Tile upper screen, in the present instance, may be supported on hanger plates 35 secured to and depending from the casing cover. Secured to the opposite sides of the screen are inclined members 37 adapted to engage the hanger plates 35 and prevent materials from escaping from the screen into the spaces between the side edges of the screen and the hanger plates.

The lower screen, in the present instance 01 the invention, comprises screen clothing 39 which may be stretched on a frame of wood or other suitable material. This frame has side members 41 connected by end members 4:3. Intermediate the side members t1 and extending longitudinally of the frame, are members 45 which may be suitably secured to the screen clothin At opposite sides of the screen are incllned memers 17 adapted to'engage the sides of the casing and prevent materials from escaping from the screen into the spaces between the side edges of the screen and the sides of the casin Suitable means may be provided for supporting the lower screen. To accomplish this, in the present instance, the lower portion of. the screen is so ported on a pair of leaf springs as (Fig. 1 having their lower ends secured to feet 51 mounted on the bottom of the casing. The upper ends of these leaf springs engage angle plates 53 secured to the side members 11, the construction being such that the lower portion of the screen is yieldably supported by the leaf springs 19, and the screen is prevented from sliding downward by engagement of the angle plates 53 with the upper ends of the leaf springs. The upper portion of "thelower screen is supported by electro-magnetic mechanism for vibrating the screen to be described.

This electromagnetic vibrating mechainseam nism, in the present instance of the invention, comprises an electro-magnet 55 having feet 57 secured to and depending from a channel 59 carried by U-shaped hangers 61 secured to and depending from the bottom of the casing adjacent the sides of the latter.

The electro-magnet has a coil 63, and cooperating therewith is an armature, in the present instance, in the form of a core 65 which projects downward into the coil, so that its lower end is spaced somewhat from a stop core 67 The upper end of the armature core is secured by a bolt 69 to a sup port, in the present instance, in the form of a channel bar 71.

The support 71 is yieldingly sustained by upper portions 73 of coil springs 7 5. Embracing these coil springs intermediate the ends thereof, are clamps 7 secured by bolts 79 to the channel 59 referred to. Each of these clamps comprises a fixed part 83 (Fig. 3) and a removable part 85 secured to the fixed part by through bolts 87, said parts having helical seats conforming to the convolutions of the spring. The construction is such that on release of the through bolts 87, the coil springs may be given a rotary motion to screw them up or down in the seats of the clamps, thereby to vary the effective lengths of the spring portions as desired.

Projecting upward through the coil springs 75 are posts 89 having their lower portions threaded to receive flanged collars 91 secured in different positions of adjustment by nuts 93, washers 95 being interposed between the collars and the nuts. The lower portions 97 of the coil springs are confined between the clamps 77 and the collars 91, and by adjustment of the nuts and collars, the tension of the lower portions of the springs may be varied as desired.

The posts 89 project upward through the coil springs and through collars 99 and nuts 100 respectively beneath and above the supporting bar 71, and threaded on said posts. The posts project thence upward through holes in the bottom of the casing, and through collars 101 and sleeves 103 mounted on the casing bottom. The upper ends of the posts are secured by nuts 105 and 107 to a cross channel or support 109.

Mounted on the cross channel 109 adjacent the ends thereof, are plates 111 riveted to said channel. Plates 113 rest freely-on the plates 111, and are secured to a transverse channel 115 beneath and secured to the side members 4.1 and the intermediate longitudinal members 45 of the lower screen frame. Sockets 117 are secured on the intermediate members 45 and resting in the sockets 117 are short posts 118 which engage plates 119 secured to a transverse channel 120 beneath and secured to the side members 29 and 111-- The construction is such that the upper lilt portions 7 3 of the coil springs and the posts 89' serve ieldingly to support the lower screen, and through the short posts 118, sup port the upper screen.

' The upper portions 73 of the coil springs are confined between the clamps 77 and the collars 99 which are secured to the supporting channel 71, and since the core 65 of the electromagnet is connected to the chan 'nel 71,-the upper portions of the coil springs will support the core in opposition to the pull thereon by the magnet.

The eleotro-magnet is in circuit with a source of electricity which is of a character or so controlled that the electro-magnetic force is rapidly varied, and the armature core is rapidly agitated or vibrated. In the present instance, the magnet is connected by conductors 123 and 125 with a source of alternating electric current which increases in a positive direction to a maximum value, falls to zero, and increases to a maximum negative value, the current frequency being such that the magnet core receives a pulsating movement, but the changes in the direction of the current are so rapid that the sup porting channel 71 is pulled down against the upper portions 73 of the coil springs 7 5 continuously, but with a rapidly varying force. The magnet and upper and lower spring portions, therefore, place the support 71 in a highly vibrant state, but the amplitude of vibration may be so small or minute that the channel support does not have substantial movement.

The vibrations or tremors of the'core and support 71, are transmitted by the posts 89 to the cross channel 109', and from the latter to the lower screen resting freely thereon, and from the lower screen through the short posts 118 to the upper screen. It will be noted that the lower screen plates 113 rest freely upon the cross channel plates 111, but are independent of positive connection therewith. As a consequence, the lower screen may float upon the cross channel, and the plates 111 pulsating or vibrating, produce a rapid succession of taps or hammer blows against the plates 113 secured to the under side of the lower screen. As a result, the longitudinal members of the lower screen are placed in a highly vibrant condition, and the vibrations thereof are transmitted to the clothing and distributed throughout the area thereof, so that all of the meshes of the clothing are maintained in open condition for efiicient grading efieot.

The upper screen may be introduced into the casing when the cover is in open position, by sliding the screen longitudinally inward along the hanger plates which depend from the cover. When the screen has been slid fully inward, the flange of the upper end member of the screen -frame will slide over a pair of leaf springs 127 mounted on the upper ends of the hanger plates. When the flange of the end member reaches the ends of said leaf springs, it will drop downward and engage the ends of said springs, thereby preventing the screen from slidin downward when the cover has been close The lower portion of the upper screen may rest on leaf springs 129 mounted on the hanger plates. g

- The upper screen iswholly supported by the hanger plates when open, and while the cover is being rocked down toward its closed position. As the cover approaches its closed position, the transverse channel 120 which is secured to the under side of the screen, and the plates 119, will be brought downward so that said plates will engage the short posts 118. This will transfer the support for the upper portion of the upper screen from the hanger plates to said posts, so that the latter will be effective to transmit the tremors or vibration from the lower screen to the upper screen.

As stated, the lower screen is mounted freely and floats on the cross channel 109, so that it may be vibrated by said cross channel, but since the screen is separate from the cross channel, it is susceptible of vibratory movements independent of and at a different rate from said cross channel. Lateral movements of the screen in the direction of the plane thereof, ma be limited by engagement of the incline members 47 with the sides of the casing. Lateral movement of the upper screen in the direction of the plane thereof may be limited by enga' ement or. the inclined members 37 with the anger plates 35.

The upper portions of the coil springs 75 yie ldingly support the upper portions of both screens, and oppose downward pull by the armature of the magnet. The lower portions of the coil springs 75 work in opposition to the upper portions of the springs, and enable the tension and efiect of the upper port-ions of the springs to be adjusted as required. It is desirable that the core of the magnet shall have its lower end adjusted a predetermined distance from the upper end of the stop core, and adjustment of the coil springs enables the space between said cores to be regulated as desired.

It will be noted that the axis of the core of the magnet is disposed in oblique position in order that it may vibrate transversely to the planes of the screens. Since the coil springs 75 are of strong construction and are securely gripped intermediate the ends thereof, the tendency is to prevent lateral flexion of the springs, and the latter there fore will so support the posts 89 and channel 71 as to relieve the core of the magnet from side pressure and friction.

The electromagnetic vibrating mechanism is located beneath the casing where it is out of the way and protected from the dust w th in the casing, and it is readily accessible for purposes of inspection, adjustment and r pair.

Also, the screens are readily accessible. W hen the cover is raised, it will carry the upper screen with it, thereby rendering easily visible both the upper screen and the lower screen. The upper screen, if desired, may be easily removed by pulling the same longitudinally outward from the hanger plates, and the lower screen may be easily removed if desired, by lifting the same from the supporting springs beneath the lower end thereof, and from the cross channel be neath the upper end thereof.

By my invention, simple and efficient electro-magnetic means is provided for placing the screen or screens in a highly vibrant condition, but the vibrations may be of small amplitude, so that there is not r0- nounced flexion of the screen clothing a ong the lines of juncture with the supporting frame therefor, and this vibration is accomplished without imparting blows directly to tile screen clothing. The construction is such that the clothing is efficiently vibrated throughout. the area thereof, so as to maintain the meshes of the clothing in open condition, but the destructive effects of the vibration, on the clothing is reduced to a minimum.

lit will be understood that the invent-ion is not limited to the specific embodiment shown, and that various deviations may be made therefrom without departing from the spirit and scope of the appended claims.

What is claimed is 1. A separator for grading materials, comprising, in combination, a support, a screen resting on, but not connected to said support, and electro-magnetic means for imparting vibrations of minute amplitude to said support and through the support to the screen in a direction transverse to the plane of the screen the latter being free to vibrate on and relatively to said support.

2. A separator for grading materials, comprising, in combination, an electro-magnet having an armature, means for energizing said magnet to produce rapid pulsations of said armature, and a screen having a frame and screen clothing, said frame being separate from the magnet and its armature and adapted to receive the pulsations from said armature in a direction transverse to the plane of the screen, the frame of the latter being susceptible of vibratory movements independent of and at a different rate from said armature.

3. A separator for grading materials, comprising, in combination, a screen having a frame and screen clothing, spring means supporting said frame, and electric means for imparting vibrations of minute amplitude to the screen frame, the being independent of said spring supporting means and electric means, that it may be susceptible of vibratory movements independent of those produced by the electric means.

4:. A separator for grading materials, comprising, in combination, a screen hav' ing a frame and screen clothing, a support for said frame, and electro-magnet means for imparting vibrations of minute amplitude through said support to the screen frame, the latter being unattached to said support and electro-magnetic means, so that said frame may be susceptible of vibratory movements independent of those produced by said electromagnetic means.

5. A'separator for grading materials, comprising, in combination, a plurality of screens, a support for one of said screens, electro-magnetic means for imparting vibrations to the support and through the latter to the screen sustained thereby, and means to transmit vibrations from the vibrated screen to another of the screens, said screens being susceptible of vibratory movements independent of those of the vibrating means.

6. A separator for grading materials, comprising, in combination, an electromagnet having an armature, spring means sustaining said armature, a screen supported freely on said armature, and means for energizing said magnet to cause the armature to vibrate with rapid pulsations and impart vibrations to said screen, the latter being free from said spring means and susceptible of vibratory movements, independent of the vibrations of said armature and spring means.

7. A separator for grading materials, comprising, in combination, a support, a screen resting on but separate from said support, and an electro magnet having an armature connected to said support, said magnet being adapted to be energized by an alternating electric current, thereby rapidly to vibrate said support, and the screen resting thereon, the screen being susceptible of vibratory movements independent of said support.

8. A separator for grading materials, comprising, in combination, an electromagnet, an armature bar cooperating with said magnet, means to energize the magnet to draw the armature bar toward the same with varying force, a screen for grading mate rials supported on said armature bar, and a pair of springs at opposite sides of said magnet supporting said armature bar and opposing movement of said armature bar toward said magnet.

9. A separator for grading materials, comprising, in combination, an electromagnot having an armature, a screen supported freely on said armature, spring means for i ii .ing means cooperatin supporting said armature, means for vary- .ing the tension of said spring'means, and

means for energizin said magnet by an alternating current, t ereby to vibrate said armature between the screen and the spring means and transmit vibration to the screen.

10. A separator for grading materials, comprising, in combination, an electro-magnet having a core, a stop adjacent the lower end of the core, a support connected to said core, spring means tending to move said support away from said magnet, adj ustwith said support to vary the distance 0 said core from said stop, a screen mounted on said support independent of positive connection therewith, and means to energize said magnet with varying force, thereby to vibrate said support and the screen mounted thereon.

11. A separator forgrading materials, comprising, in combination, an electro-magnet having an armature, spring means supporting said armature, a screen freely supported by said armature, means to energize said magnet with varying force, thereby to vibrate the armature and the screen supported thereon, a seal r screen above the firstnamed screen, an means to transmit vibrations from the latter to the scalper screen.

'12. A separator for grading materials, comprising, in combination, a casi prising a bod and a cover, hangers. epending from sai cover, a scalper screen adapted to be supported by said hangers, a lower screen beneath the seal er screen, electromagnetic-means for v1 rating the lower screen, and means to lift the scalper screen from said hangers and impart vibration COIII'.

thereto from the lower. screen when the cover is in closed position.

13. A separator for grading materials, comprising, in combination, a screen, a support for the screen, and electrical means for imparting vibrations of minute amplitude through the support to the screen in a direction transverse to the plane of the latter, said screen resting on sa1d support but unattached thereto so that the screen may have vibratory movements on said support independent of those of said support.

14. A separator for grading materials, comprising, in combination, a screen havin a frame and screen clothing carried by sai frame, means supportin the frame and unattached thereto that the screen may move up and down relatively to the support, and electrical means for imparting a rapid succession of vibratory movements to the supporting means, and through the latter to the screen frame.

15. A separator for grading materials, comprising, in combination, an inclined screen having a frame and screen clothing, means for supporting the lower end ,of th frame, sprin means for supporting the upper end of t e frame, and electrical means cooperating with said s ring means for imparting vibrations to t e upper end of the frame, the latter being unattached to the electrical means so that the frame may be susceptible of vibratory movements independent of those produced by said electrical means.

In testimony whereof, I have signed my name to this s ecification.

TH MAS J. STURTEVANT.

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