US1839614A - Screen - Google Patents

Description

Jan. 5, 1932. l.. G. SYMONS 1,839,614

SCREEN Filed Nov. 13, 1929 5 Sheets-Sheet l M fiar/MVS L. G. SYMONS Jan. 5, 1932,

SCREEN Filed NOV. 13 1929 i. "lll, x l H. ril

Jan. 5, 1932. L G. SYMONS 1,839,614

SCREEN Filed Nov. 13, 1929 5 Sheets-Sheet 3 @MQ/wm Patented Jan. 5, ,1932

UNITED STATES PATENT ori-1er LOBEN G. SYMONS, F HOLLYWOOD, CALIFORNIA, ASSIGNOR T0 SYHONS BBODMLOP- MENT COMPANY, 0F LOS ANGELES, CALIFORNIA, A. COMORATION' OF DELAWARE SCREEN' Application. mea November 1s, 1929. serial m. mensa. v

My invention relates to an improvement in screens and relates particularly to an improved vibratory screen. One object of the invention is the provision of a screen, iexible 5 from end to end, which screen includes sections of different mesh. Another object is the provision of a screen structure, including' sections of different mesh, to which may be imparted a Wavelikevibration the waves of which pass along the entire screen structure,

actuating all the various sections and imparting to all of them a vibration of substan tially uniform amplitude. Another object is the provision of tensional iiexible supporting members for such a screen, which supporting members iex with the screen, and extend along and support the entire screen series of sections of different mesh. p Another object is the provision of means permitting the ready .20 removal of individual and separable screen Figure 6 is a section on the line 6-6 of 3,5 Figure 1. Like parts are indicated by like symbols throughout the speciication and drawings.

Referring to the drawings, A generally indicates any suitable frame member, of which I show the side channel members A1 A2 which may be connected as by the transverse end member A3. In order to support the frame and screen at any desired angle I may employ supports AA1 A5 of unequal height. A6 A7 are brackets welded to the ends of the channels A1 A2, each bracket including a generally cylindrical portion A8 with a restricted aperture A9 facing the opposite end of the screen and an enlarged aperture A1. A11 indicates a circumferential ledge or seat the purpose of which will later ap ear. A1 is a transverse brace or tube welded to the side channels A1 A2.

B generally indicates any suitable screening member, herein shown as of mesh. It is mounted upon a plurality of transverse members B1, which may be'relatively rigid and may, for example, be of wood, and which extend from side to side of the screen. These members B1 are secured to longitudinal cables B2 B2, extending along each side of the screen and being herein shown as of reater length than the screen and extending eyond the screen at each end thereof. The members B1 may be secured in relation to the cables or flexible tensional members B2, as by the lower clamp members B3, the up er clamp members B*1 and the securing bolts I3". B indicates any suitable cushion or more or less iexible member which may be interposed between the clamp B4 and the cable, in order to prevent a metal to metal contact, in case a metal cable is employed. B" indicate any suitable clamps, spaced along the members B1, whereby the mesh may be secured to the said transverse members at suiciently frequent intervals to insure that the entire structure vibrates virtually as a unit, and to constrain the mesh to downward vibration or movement with the supporting structure. Thus any whipping or free movement of the mesh is prevented and the entire structure can be vibrated as a unit.

It will be noted, as in Figures 1 and 2, that the screen or mesh, generally indicated as B, is divided into a plurality of separate and separable sections or panels. Referring to Figure 1, I illustrate panels, B1", of relatively fine mesh, panels B11 of intermediate mesh, and panels B12 of coarse mesh. Thus as the material undergoing separation passes along the screen there is a successive classification, the fines passing through the sections B1o and the largest particles passing over the end of the screen. I may employ any suitable separate means for receiving the discharge from the various sizes of mesh. I indicate, as in Figure 2, any suitable receiving hoppers or chutes B11 for the nes, B11 for the intermediate size, and B1l5 for the ma- 100 terial passing through the mesh B12. It will be noted that the indlvidual sections or panels are shown in Figure 1 as having thelr opposed edges termma'ting along or above the 5 transverse members B1, to which they are clamped as by the above'described clamp members Ba B4 B5. The individual screen panels, in case they Wear or sag or are otherwise damaged, may be separately and individually removed, without the replacement of the entire screening surface.

Positioned along the opposite edges of the screen are the flexible material guidin walls indicated as C C1. They are prefera ly of material which will flex with the screening and with the fiexible members B1. v'I may, for example, employ strips of rubber. These strips may be clamped in place, as by clamping elements Cz and U-bolts Cs which may pass about the members B1. These strips overlie the edges of the individual screen panels and may be employed to serve as clamps or to help in clamping or securing the side edges of the individual screen sections.

Whereas I de not wish to be limited, except so far as I limit myself inthe claims, to any specific cable structure, I illustrate the members B2 as metal cables, formed of a plurality of metal strands or wires. In order to support these cables within the above described frame and to maintain them under About the end of the cable I illustrate a sleeve D the outer end of which is outwardly tapered as at D1, to provide an expansion of its bore to a diameter greater than the normal diameter of the cable B2. The end of the cable may be morev or less frayed out, as shown in Figure 5, and mtal or any other suitable packin or expanding medium D2 may be employe to provide an expansion or enlargement of the cable end which will prevent it from drawing through the sleeve D. Zinc isa satisfactory metal to be employed as an expanding filler for the cable end. In order to prevent the necessity of placing zinc in the cable in the field, I may provide the sleeve D, which is channeled as at D, with a pair of outwardly projecting half rings D4 which may be put in place after the full ring D5 has been sllpped about the cable. Da indicates a spring compressed between the ledge A11 and the ring D5, and tending to maintain the cable under constant tension.

In order to maintain both cables under a uniform tension, and to compensate for what would otherwise be differences in tension, I Bovide a transverse yoke E. This yoke may secured to the end frame member A5, as by the pin or bolt E1 which 'passes through an aperture E2 in the frame. Surrounding the end.of the member or bolt E1, where it passes throulgh the aperture, is any suitable washer Ea aving associated therewith a more or less spherlcal surfaced bearing member E* opposed to a spherical surface member E5 about the bolt E1. E8 Ee are any suitable adjusting and locking nuts, whereby the tension on the entire structure may be varied. It will be understood that the proportion of the parts is such that the yoke E may tilt somewhat about its point of support, this movement being permitted by the size of the aperture E2 and the spherical formation of the opposed engaging members E* and E5. Preferably lI constrain the yoke E to horizontal position, or, rather, to a position'normal to the lane of the frame. I may therefore provi e blocks ET opposed to the ends of the transverse oke E, the bolts and nuts E8 E9 being provi ed to take up the slack and to prevent any up and down movement of the yoke due to the vibration of the xcables.

Formed in each end of the yoke i's a socket G with a ledge G1 and an aperture G2 through which may pass the end of the cable B2. Gs indicates av sleeve about the cable, with the abutment ledge G* and the enlarged central aperture G5 to receive the unraveled end of the cable, withits filler G5, for example of zinc. Com ressed between the led es or abutmentsV 1 and G* is the spring 1. As` shown in Figure 5 it will be seen that each end of the cable is yieldingly mounted, the two springs D5 and G7 serving to put the cable'under' any desired tension, this tension being equalized by the yoke E.

In order to impart vibration to the cables I provide the lvibratory structure below described. A transverse housing'H, with terminal enlargements neath and mounted upon the frame. I may Yemploy for example the supporting webs H5 with the opposite end. Referring again to Figure 6, H9 indicates a cylindrical eccentric member surrounded by the inner ball race H10, the ball bearings H11 and the outer race H11. The outer race is mounted in the leye of a vibration transmitting link which includes the annular member H13 and the shaft or stem H14 extending upwardl therefrom. H15 is any suitable counterweig t associated' with the shaft H5.

In order to transmit movement of the ele- 1 H2 is positioned be- Athe connector H11, as by the' screwthreaded bolt portion J2 and the nut J 2. J 1 is a. spacer about said nut. The clamp elements J J1 may be secured together as by the bolts J" and the nuts J". J s J s are yielding pads associated with the clamp member, one engaging the upper and the other the lowery side of the cable B2. Theseypads serve to prevent a metal to metal contact andto more or less cushion the connection between the connector H14 and the cable, thus limitingwear.

In order to prevent the access -of dust to the working parts and to reduce the lubricating problem I provide a flexible connection between the above described clamp structure and the enlarged housing portion H1. This may take the form of a iexible member J 9, herein shown as tubular, the ends of which may be clamped into dust proof engagement with the housing portion H1 and the clamp structure J1 respectively, as yby the rings JIO Jll.

I ymay provide any suitable means for rotating the sha-ft H5 and as an illustration of a practical method I illustrate theshaft extension H2o with the pulley H21 thereupon.

In order further to constrain the material passing over the screen to longitudinal travel along the screen, and to prevent it from escaping from the edge'of the screen, I provide, in addition to the fiexible walls C1, the inner guiding walls enerally indicated as K. 'Ihese may be of s eet or strip metal and are shown, as in Figure 4, as termina-ting somewhat above the mesh, and as being ositioned within the iexible walls C C1. The iexible walls C-C1 bridge the gap between the normally fixed members K, and prevent any friction or damaging or wearing Contact between the members K and the mesh. The members K may be mounted upon brackets K1 pivoted as at K2 to the longitudinal frame members A1 or A2, whereby the members K may be rotated out of vertical alignment with the mesh, as shown at the left of Figure 4. This is advantageous, as giving full contact to the mesh, and as permitting the mesh to be lifted into and out of place, in setting up the screen.

It will be realized that whereas I have described and shown a practical and operative device, nevertheless many changes might be made in the size, shape, number and disposition of parts without departing from the spirit of my invention. I therefore wish my description and drawings to be taken as in a broad sense illustrative and diagrammatic, rather than as limiting me to my specific showing. In particular I wish it to be understood thatmere variations in proportion or loc'zation of parts do not depart from my invention.` Where in certain of the claims I describe cables as extending from end to end of a screen member it will be understood that such claims are to-be interpreted suiciently broadly to cover a screen in which the distance between the cables exceeds the length of the screen.

The use and operation of my invention ar as follows:

I provide herein a screen member to whic may be imparted a wavelike vibration. In practice I nd it desirable and 'adding highly to the eiiciency of the screen that the ampliytude. of vibration be as nearly as possible uniform throughout substantially all points on the effective screening area. I impartthe desired vibration to my screen by supporting themesh B upon iexible supporting memp bers, for example the cables B2, which extend will flex transversely of its ends but which` will not iex longitudinally. Hence I may impart to the screen a uni-directional wavelike vibration, and the crests and troughs of the waves of this vibration will extend from side to side of the screen, with equal ampitude, and will move longitudinally alon the screen, unimpeded by any stifening or ampering frame or other supporting means. The nature of this wavelikQvibrati-.on which is imparted to the cables B2, and through them to the screen, is illustrated somewhat diagrammatically,- in Figure 3. The position of the cable at one instant is indicated in full line as at X. The position of the cable at another limit 'of its vibration is indicated in dotted line as at Y. Note that lthe cable indicates the wavelike formation and travel of the vibration,y with the wave troughs X1 X2 and the wave trough Ya. Thus each point along the screen is vertically vibrated through 'a vibration of uniform amplitude, while the individual waves of this vibration travel in definite sequence from end to end of the supporting members and screen.

As the screen structure includes panels ofvarying mesh, it will be understood that the vibration imparted to the iexible supports extendsthroughout the entire screen series, imparting a characteristic wavelike vibration of uniform amplitude for all the screening sections.

As an eifective means of imparting the desired vibration to tlie cables B2 I provide the eccentric structure shown in detail in Figure 6. Its effect, broadly stated, is the vertical reciprocation or oscillation of the upper end of the member H1". The lower end, the e e H, is constrained to a circular oscillation by its position about the rotated eccentric H9. But this movement is translated, so far as relates to the point of connection of the clamping structure with the cable,

. to a vertical reciprocation or oscillation.

This oscillation or vibration is imparted to each cable B2 in unison and it is imparted `to the cables, adjacent their upper ends, and adjacent the upper ends of the screen. The point of application shown in Figures 2 and 3 is a. convenient one. It will be understood that I might apply the vibrations elsewhere along the length of the flexible members B2. In any case, the vertical oscillation of the upper end of each of the cables imparts to the cable the characteristic wavelike vibration diagrammatically shown in Figure 3, and this wavelike vibration is fully imparted to the entire surface of the screening mesh through the members B1 and the clamps. Although the oscillating mechanism is mounted on the frame, it is in cushioning engagement with the cables, through the pads J 8. The cables themselves, being yieldingly mounted at each end, cannot transmit their vibrations to the frame. In practice, although the screen is undergoing 'a rapid and ample vibration, the frame does not vibrate and will not vibrate even though it may be supported loosely on the floor of a plant. The rotation of the shaft H*s imparts no vibration to the frame, because thc shaft is provide with proper counter weights. No vibration is imparted to the housing portion H1, because its sole connection with the vibrated cables in through the flexible housing J 9, which of course transmits no shock or vibration. It is therefore possible to employ a. light, open screen frame and to employ light and simple supporting means therefor. The frame is freed from wire or vibratory distortion.

rIfhe movement of the cable resembles that of the body of a snake when crawling, the wavelike vibration, however, being in a generally vertical plane. It istrue that the cable could be vibrated slowly enough to cause it to vibrate as a violin string, which would give a pronounced movement' in the center of the screen, with the amplitude of vibration diminishing from the center toward both ends. But in practice in the structure shown herein, a somewhat more rapid rate of vibration causes the travel of waves lengthwise along the cable and all parts of the screen cloth supported on the cable will be given yan upward movement along the full length of the cloth, with ever wave set up, and a downward movement, t e upward and downward movements corresponding to the dierence between the crests and troughs of the waves which travel along the screen. The mechanism is actuated at such speed that the waves follow each other in rapid succession, the crests and troughs extending transversal across the screen from edge to edge, and fo low eachother lengthwise along the screen. As earlier stated, the screen reproduces the vibratory movement of the cables in a downward as well as in an upward direction,the transverse members B1 and their clamps rendering this the necessary result of the vibration of the cables.

The material is held on the screen by means of the rubber or flexible strips C C1, which are fastened securely along each edge of the cushion and which vibrate freely with the cushion and with the cables B2. The addi- .tional stationary sides fit inside the rubber strips but are positioned .far enough from th e screen cloth to prevent contact or wear. The result is a saving in power and a decrease in the amount of Ivibration transmitted to the supporting frame. The hinging of the stationary sides permits the screen cloth to be removed with a minimum of work. The rubber strips serve also as clamping means for holding the edges of the individual screen panels.

The tensional mounting of the cables is an important and probably a necessary element in the production of the wavelike movement of the cables, as when the movement is set up in the cables it has a tendency to shorten the distance from one end of the cable to the other. The springs Gr'r and D6 take care of this variation in length, and permit the cable to take this wave movement without adding any undue strain due to the increase in tension. The springs also prevent any tendency to throw back a wave in the opposite direction, and each wave, as it reaches the end of the cable, is killed through the ilexibility of the springs. This is important, since if a return wave were set u it would kill the next initial wave traveling in the opposite direction at the point Where they meet.

In connection with the wavelike vibration the transverse yoke or equalizer E is of great importance, as unless the tension of one cable is almost exactly the same as the tension of the other there will be a marked difference in the length and height of the Waves produced by the eccentric action. The result of the use of the yoke is not only to equalize the tension of the cables, but to equalize the rate and amplitude of vibration throughout the width of the screen. In its action the screen suggests the dusting of a carpet by holding a strip at its two corners and moving it up and down, to cause waves of vibration to travel from end to end of the carpet. In this connection will be understood the importance of providing a screen which is trans' versely flexible but longitudinally inflexible. I mean a screen which will ex to permit transverse waves of vibration to move from end to end of the screen, but will not flex to permit waves of vibration to move laterally across the screen. In this sense the screen is flexible transversely, but is held against longitudinal lexure.

While it may be preferable to employ a spring connection between each end of each cable and the fram-e and yoke respectively, as shown in Figure l, I find it desirable under some circumstances to eliminate one of the springs and to eliminate the yielding connection for one end of each cable. For example I may omit the spring Do and let the abutment D5 engage the abutment A11. 0r any other suitable abutment means may be emat any ployed for maintaining the end of the cables B2 connected to the frame. In such case the springs at the upper end of the cable, the springs G7, may be employed to take care of the shortening and lengthening of the distance, to permit the wave-like vibration to take place, but the solid connection of the opposite end of the cable may produce a much stronger vibration throu hout the lower portion of the screen cloth than would otherwise be produced. In the accompanying claims it will be understood that I do not wish to limit myself to the employment of a yielding connection for each end of the cable unless I specifically so limitmyself by the language of the claims. Also I do not wish to be limited, when employing a single yielding connection, to the position of that connection specifically 'ven end of the cable, except so far as I speci cally so limit myself. In practice a very satisfactory arrangement is to connect the cables yieldlngly to the yoke E and un` yieldingl at their opposite ends,to the frame.

`My tests ave indicated that the'yielding connection at the vibration 'transmltting end of the cable, namely between cable and yoke, is effective in preventing return vibration or return waves of vibration along the cable.

I claim:

1. In a screen, a fiexible screen member, a plurality of cables, upon which said flexible screen member is mounted, said screen including a plurality of sections of vary'in mesh spaced along said cables, and means or imparting to said cables and, thereby to the sections of said screen member, a wave-like vibration, of substantially uniform amplitude from end to end of the screen member and means for maintaining said cables under tension.

2. In a screen, a flexible screen member, a plurality of cables, upon which said flexible screen member is mounted, said screen includ ing a plurality of sections of varying mesh spaced along said cables, and means for imparting to said cables and, thereby to the sections of said screen member, a wave-like vibration, of substantially uniform amplitude from end to end of the screen member, and means for maintaining said cables un-der tenslon, and means for constraining the screen member to a substantially uniform amplitude of vibration from side to side thereof.

3. In a screen, a flexible screen member, a plurality of cables, upon' which said flexible screen member is mounted, said screen including a plurality of sections of varying mesh space along said cables, and means for lmparting to said cables, and, thereby to the sections of said screen member, a wave-like vibration, of substanti ally uniform amplitude from end to end of the screen member, means for maintaining said cables under tension, and means for constraining the screen member to a substantially uniform amplitude of vibration, from side to side thereof, including transverse supporting members extending between the cables, and means for holding the screen against movement in relation to said transverse supporting members.

Signed at Hollywood, county of Los Aneles and State of California, this 23rd day of 'cmber 1929.

LOREN G. SYMONS.

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