US2077678A - Screening apparatus - Google Patents

Description

April 20, 1937. G. R. DELAMATER SCREENING APPARATUS Filed March 3, 1933 3 Sheets-Sheet 1 INVENTOR. 6 co r 6 fyZa me 76/ April 1937- G. R. DELAMATER 2,077,678

SCREENING APPARATUS Filed March s, 1935 3 Sheets-Sheet 2 INVENTOR. 660796 A? Z7eZama7 /r BY ATTORNEYS April 20, 1937. G. R. DELAMATER SCREENING APPARATUS Filed March 3,- 1935 3 Sheets-Sheet 5 r 6 M M m I P .6 .9 A 73 68 6 however, but one of various ways in which the.

Patented Apr. 20, 1937 UNITED STATES SCREENING APPARATUS George R. Deiamater, Shaker Heights, Ohio, as-

signor to The W. S. Tyler Company, Cleveland, Ohio, a corporation of Ohio Application March 3, 1933, Serial No. 659,573

. 1 Claim.

The present improvements; relating as indicated to screening apparatus, are more particularly adapted to improved apparatus for screening or classifying materials, although, as will be apparent from the following description, the use of the present apparatus is not necessarily limited to any particular type of material. One of the principal objects of the invention is the provision of a simple and rugged apparatus for accurately classifying bulk material, providing a close separation and handling a large tonnage. A further object of the invention is the provision of apparatus which will carry out the above purposes with a minimum of maintenance expense.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claim; the annexed drawings and the following description setting forth in detail certain means of carrying out the invention, such disclosed means illustrating,

principle of the invention may be used.

In said annexed drawings:-

Fig. 1 is a view in perspective, partially sectioned, of one form of my improved apparatus; Fig. 2 is a side elevation of one corner of the apparatus, showing one of the means for imparting movement to the screening surface; Fig. 3 is a transverse'central section through one 'of the vibrating means;'and Fig. 4 is a partial plan view, partially in section, of one comer of the apparatus showing the relation between the frame and one of the vibrating mechanism.

In the classifying of bulk materials the two generally employed methods are the separation of material by air, which is ordinarily applied only to remove the extremely fine material from the coarse and vibrating, shaking or other types of screens for the separations which cannot be handled by air separation methods.

This apparatus employs woven wire cloth as the final separating instrument and provides for uniform ten'sioning of this cloth which assures maximum screening eificiency and life of screen cloth. Provision is also made to vibrate this cloth rapidly in a plane at an angle to the plane of the material passing thereover. Materials of almost any reasonable size may be fed to this apparatus but its type of vibration makes it more suitable for vibrating screen cloth not exceeding 1%" clear opening.

In the present apparatus I have developed a simple and rugged mechanism for the handling of coarse material in which a frame carrying a section of taut woven-wire screen is vibrated uniformly throughout its area by simple and rugged mechanism disposed preferably at the corners of the rectangular frame, the mechanism being also provided with means for accentuating or increasing the movement given to the frame by the vibrating mechanism. In Fig. 1 I have shown a view in perspective of one form. of my improved apparatus consisting of a supporting frame composed of I-beams I and 2, which are rigidly secured together to form a rectangular enclosure which is mounted upon any suitable supports in an inclined position, as shown in Fig. 1. The mounting or base for the rigid frame may of course take various forms and may be provided, as is common in such apparatus, with means for adjusting the inclination of the frame for various purposes. Mounted within the outlines of the base, but above the screen, is a second and separate rectangular frame consisting of end members 3 and side angles 4, which are rigidly secured together and provide the frame on which the woven wire screen or screen bar or rods are mounted. Mounted longitudinally and equidistantly from the side channels 4 are anglemembers 5 and 6 which are rigidly secured to the end members 3 of the movable frame and which act to stiffen this frame and to provide raised members, over which the screen cloth I may be stretched to give the latter a curved or arched upper surface. To further insure complete rigidity, the longitudinal angles 4 of the movable frame are reinforced by truss members H! extending from end to end of each angle. The movable frame is further stiffened by means of transverse members 9 mounted below the plane of the screen so that the movable frame is an extremely rigid, rectangular member for supporting the screen in a predetermined condition as regards the contour of the upper surface and the tension.

Since the screen-receiving frame Just described is mounted in an inclined position and is freely supported between springs acting at an angle to the plane of the screen, as will presently be described, it will be desirable to anchor the frame in a predetermined position with respect to the base,. the supporting springs to be described and the vibrating means. For this purpose I employ members l5, which of fiat strip elements which are fixed in spaced brackets l6 intermediate the ends of the frame and which, at their ends, are attached to U-bolts 50 engaged with channel members 18 which are secured to the ends of the screen-receiving frame.

These guide members i5 serve the double purpose of maintaining the frame in the desired position with respect to the base, the supporting springs and the vibrating mechanism and absorb all end thrust which might otherwise be directed onto some part of the vibrating mechanism or the spring supports.

The extending portions i8 of the transverse frame members 3 are secured to the armature 20 of an electromagnetic device which is mounted are here shown in the form upon a coil spring it supported upon a suitable plate 22 carried in an enclosing housing 23, one of which is'mounted at each corner of the entire frame. The armature 2G is actuated by an electro-magnet 26 mounted in the upper portion of the housing 23, where it is appropriately secured. Mounted in an extension housing 3t secured in the main housing 23 is a spring 25, which engages against the top of the frame end iii, causing this frame end and the entire movable frame to be fioatingly supported between the springs 2i and 25. The latter spring may be adjusted as to its tension by means of an adjusting bolt 26 and thrust plate 2?, adjustment being had by removing the top or cover 28 of the extension housing.

The woven wire screen i is provided with a reinforced rebent edge portion adapted to be secured by hook bolts 36, which are carried in the longitudinal side members i of the movable frame where they are adjustably secured by means of nuts bl. By loosening the nuts 37, the bolts may be moved inwardly toward the center of the movable frame a sumcient distance to permit the rebent hooked edges of the screen i to be caught, after which the bolts can be tightened to bring the entire woven Wire screen into any desired tension and into a curved condition over the supporting members 5 and t in the central portion of the frame. A guard 39 is pivotally mounted about a longitudinally extending rod Mi carried upon suitable posts extending upwardly from the longitudinal members l of the inner frame, and this guard may be swung upwardly about its axis to permit of removal of the screen and is provided with an inwardly curved lower edge ill adapted to fit between the book ends of the bolts as and the curved edge strip of the screen so that tensioning of the bolts locks the guard member into the position shown in Fig. 1, and the latter prevents the leakage of any material through the side of the frame. The bolts, guard and edge portion of the screen are so proportioned that tensioning of the bolts tightens the reinforced edge portion of the screen against the horizontal flange d2 of the angle.

4 adjusting the tension of the spring 25, but regardless of this adjustment the mounting of the entire frame is made resilient and lively and the movement thus imparted to it permits a relative ly small current consumption to provide a rapid, lively and, if desired, wide amplitude of movement for the screen frame which produces a sharp separation and a marked increase in tonnage over machines heretofore used in the screening of coarse materials. By this mechanism all portions of the screen surface are in precisely the same degree of tension and are given the same degree of movement, which has never been the case with prior apparatus commonly used for the classifying of coarse material, and this accounts partially for the increase in the capacity and also for the increase'in the accuracy of the separation.

While I have referred above to the. fact that it is possible, if desired, to impart a considerable amplitude of movement to the entire screen, it

aoraere will be evident that one of the chief distinctions of the present apparatus over prior mechanically operated screening apparatus is that a very much shorter amplitude of motion imparted to the screen surface will have a greater effect than in prior machines. In any machine in which vibration is imparted directly to the screen surface either at the center of the screen or along the center line of the screen which is stretched between any two spaced edges, the amplitude at the point of connection of the vibration-imparting apparatus has to be greater than is really desirable in order to produce an approximation of the desired amplitude at points spaced from the point of connection. In one type of screening apparatus in which one or more electro-magnets are secured to the screen along a central line a screening action is secured which has been superior in the screening of fine materials to that obtainable by any other apparatus, but

even this machine has represented a compromise in that an excessive amplitude of movement had to be imparted to the center of the screen. in order to secure the desired amplitude between the central part and the edges. It is of course impossible in such an apparatus to secure the same amplitude all over the surface, and the edge portions are substantially unvibrated and represent dead areas so far as active screening is concerned.

The present apparatus for the first time presents a machine for the screening of fine materials in which the entire screen surface is in tension and therefore equally effective and equally resistant to wear, and in which a rapid electro= 7 magnetic vibration can be imparted to the entire screening area instead of the slower mechanical vibration imparted by unbalanced weights, cranks cams and. similar devices. Furthermore, exactly the desired strolre can be given to the screen and this amplitude will be uniform all over the screen surface. This inevitably increases the tonnage and the accuracy of the separation, while the movement of the entire screen and screen frame at an angle to the plane of the screen allows a lower screening angle, again tending to increase the tonnage, and acts to feed the material over the screen surface. The lower the screen angle and the shorter the amplitude of movement, the more continuous the contact between the material and. the screen and the greater the opportunity for the particles to pass through the meshes of the screen, which of course tends to increase the capacity and the accuracy.

Other'modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the means herein disclosed, provided those stated by the following claim or its equivalent be employed.

1 therefore particularly point out and distinctly claim as my invention:-

In a screening apparatus the combination of a I. base, a rigid frame mounted in an inclined position, resilient supporting means mounted between said base and frame, and resilient cushioning means above said frame, said frame being rectangular, thus providing corners, there being electrc-magnetic vibrating means mounted at each corner, said frame being maintained in superposed position with respect to said base by means of resilient anchoring elements connected to the central portion of said base and to the opposite ends of said frame.

- GEORGE R. DELAMATER.

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