US1839610A - Screen - Google Patents

Description

L. G. SYMONS Jan. 5, 1932.

SCREEN Filed Nov. 13, 1929 3 Sheets-Sheet l w w. E m

jam. 5, l932. G SYMONS 1,839,610

SCREEN Filed Nov. l5, 1929 3 Sheets-Sheet 2 L. G. SYMONS Jan. .5, 1932.

SCREEN s sheets-sheet s Filed Nov. 13, 1929 Wye/fa? [0r6/f @15j/730W.;

fiar/76361 ww MSN Patented Jan. 5, 1932 STATES- LOREN G. SONS, OF HOLLYWOOD, CALIFORNILBASSIGNOB. TO SYTEONS BROS. DEVELOP- MENU.' COMPANY, 0F LOS ANGELES, CALIFORNIA, A CORPORATION 0F DELAWARE SCREEN Application led November 13, 1929. Serial No. 406,780.

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 which shall be flexible from end to end. Another object is the provision of a screen structure to which may be imparted a wave-like vibration, the Waves of the vibration passing from end to end of the screen. Another object is the provision of tensional, fiexible supporting members for a screen, which supporting members fiex with the screen. Another object is the provision of means for constraining the screen to vibration in unison vwith its tensional supporting means. Another object is the provision of a screen having a wave-like vibration of consta'nt or relatively constant amplitudeI throughout the effective area of the screen. Other ob jects will appear from time to time in the course of the specification and claims.

I illustrate my invention more or less diagrammatically in the accompanying drawings, wherein- Figure 1 is a plan view;

Figure 2 is a section on the line 2 2 of Figure l;

Figure 3 is a section on the line 3 3 of Figure 1;

Figure 4 is an end elevation;

Figure 5 is a detail; and

Figure 6 is a section on the line 6-6 of Figure 1. Y

Like parts are indicated by like symbols throughout the speci fication 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 emi ploy supports A1 A5 of unequal height. A*1

A7 are brackets welded to the ends of the channels A1 A2, each bracket including a generally cylindrical portion A8 with a restricted aperture A, facing the opposite end of the screen and an enlarged aperture A10. A11 indicates a circumferential ledge or seal the purpose of which will later appear. A12

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 ri id and may for example be of wood, and w 'ch entend 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 length than the screen and extending. yond the screen at each end thereof. The members B1 may be secured in relation to the cables or flexible tensional members B1, asby the lower clamp members B3, the upper clamp members B4 and the securing bolts B5. B6 indicates any suitable cushion or more or less flexible member which may be interposed between the clamp B*1 and the cable, in order to prevent a metal to metal contact, in case a metal cable is employed. B7 indicates any suitable clamps, spaced along the members B1, whereby the mesh may be secured to the said transverse members at sufficiently 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.

Positioned along the opposite edges of the screen are the flexible material guiding Walls indicated as C C1. They are preferably of material which will flex with the screening and with the flexible members B2. I may for example employ strips of rubber. These strips may be clamped in place, as by clamping elements C2 and U-bolts C3 which may pass aboutthe members B1.

Whereas I do not wish to be li mited, ex cept so far as I limit myself in the 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 tension I provide an enlarged head at each end of each cable. Referring for example to eater Figure 5 I illustrate one end of the cable as ment of the cable end which will prevent it has been slipped about the cable.

from drawing through the sleeve D. Zinc is a satisfactory metal to be employed as an eX- panding filler for the cable end. In orden` to prevent the necessity of placing zinc in the cable in the field I may provide the sleeve D, which is channeled as at D3, with a pair of outwardly projecting half rings D4 which may be put in place after the full ISing (35 1 in icates 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 provide a transverse yokecE. This yoke may be secured to the end frame member A1, 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 through the aperture is anysuitable washer E3 having associated therewith a. more or less spherical surfaced bearing member E1 opposed to a spherical surface member E1 about the bolt E1. E11 E6 are any suitable adj usting 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 engagingmembers E1 and E5. Preferably -I constrain the yoke E to horizontal position, or rather, to a position normal to the plane of the frame. I may therefore provide blocks E7 opposed to the ends of the transverse yoke E, the bolts and nuts E8 E9 being provided to take up the slack and to prevent any up and down movement of the yoke due to the vibration of the cables.

Formed in each end of the yoke is a socket G with a ledge G1 and an aperture G2 through whichmay pass the end of the cable B2. G1 indicates a sleeve about the cable, with the abutment ledge G* and the enlarged central aperture G5 to receive the unravelled end (if the cable, with its filler G, for example of zinc. Gom ressed between the ledges or abutments 1 and G1 is the spring G1. As shown in Figure 5 it will be seen that each end of the cable is yieldingly mounted, the two springs D5 and G1 serving to put the cable under any desired tension, this tension being equalized by the yoke E.

Inl order to impart vibration to the cablesl I provide the vibratory structure beloW described. A transverse housing H, with terminal enlargements H1 H2 is positioned beneath and mounted upon the frame. I may employ for example the supporting Webs H3 with their flanges H1, which may be bolted to the longitudinal frame members A1 A2. Mounted for rotation Within the housing H is any suitable shaft or rotary member H5. It may be provided at each end with an inner ball race He fixed on the shaft, an outer ball race H7, and the intervening ball bearings H1. Figure 6 generally illustrates an eccentricat one end of the shaft H5 and it will be understood that a corresponding eccentric and actuating structure is associated with the opposite end. Referring again to Figure 6 H0 indicates a cylindrical eccentric member surrounded by the inner ball race H10, the ball bearings H11 and the outer race H12. The outer race is mounted in the eye of a vibration transmitting link which includes the vannular member H13 and the shaft or stem H11 extending upwardly therefrom. H15 is any suitable counterweight associated with the shaft H5.

In order to transmit movement of the element H11 to the cables B2 I provide a clamping structure which includes the upper clamp element J and the lower clamp element J1. The lower element J1 may be secured to the connector I-I11, as by the screwthreaded bolt e portion J2 and the nut J 3. J 1 is a spacer about said nut. The clamp elements J J1 may be secured together as by the bolts J 5 andthe nuts J1. J1 J 8 are yielding pads associated with the clamp member, one engaging the upper and the other the lower side of the cable B2. These pads serve to prevent a metal to metal contact and to more or less cushion the connection between the connector .H11 and the cable, thus limiting Wear.

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 flexible member J 2, 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-by the rings J1o I may provide any suitable means for rotating the shaft H5 and as an illustration of a practical method I illustrate the shaft extension H2 with the pulley H21 thereupon.

In order further to constrain the material passing over the screen to longitudinal travel in addtionto the flexible walls C1 the inner IIJ guiding walls generally indicated as K. These may be of sheet or strip metal and are shown, as in Figure `4, as terminating somewhat above the mesh, and as being positioned within the fiexible Walls C C1. The flexible walls C C1 bridge the gap between the normallyfixed members K, and prevent any friction or damaging or wearing contactbetween the members K and the mesh. The members K may be mounted upon brackets K1 pivoted as at K2 to the longitudinal frame lnembers 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.

` will not flex longitudinally.

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 thatwhereas I have described and shown a practical and operative device, nevertheless many changes might be Iliade 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 that mere variations in proportion or location of parts do not depart from my in- :ve-ntion. Where in certain ofthe 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 sufliciently 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 are as follows:

I provide herein a screen member to which may be imparted a wave-like vibration. In practice I find it desirable and adding highly to the eiiiciency of the screen that the Vamplitude of vibration be as nearly as possible uniform throughout substantially all points on the effective screening area. I impart the desired vibration to my screen by supporting the mesh B upon flexible supporting members, for example the cables B2, which extend along opposite edges of the scree'n and which not only flexibly support the screen, permitting it to flex freely, but are themselves the intermediary between the vibration imparting mechanism and the screen, and transmit to the screen the vibration which they receive. In order to cause the screen to vibrate completely in unison with the members B2 I mount the screen upon the relatively rigid transverse members B1, and clamp the screen to these members B1 at a number of spaced points- The result is a screen which will flex transversely of its ends but which 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 amplitude, and will move longitudinally alonO' the screen, unimpeded by any stifi'ening or amgering frame or other supporting means.

he nature of this wave-like vibration 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 the cable indicates the wave-like formation and travel of the vibration, with thewave troughs 'X1 X2 and the wave crest X3, or the wave crests Y1 Y2 and the wave trough Ys. Thus each point along the screen is vertically vibrated through a. vibration of substantially uniform amplitude, while the individual waves of this vibration travel in definite sequence from end H9. But this movement is translated, so far p 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 B1 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. 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 wave-like 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 J8. The cables themselves, being yieldingly mounted at each end, cannot transmit their wibrations 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 H5 imparts no vibration to the frame, because the shaft is provided with proper counterweights. No vibration is imparted to the housing portion H1, because its sole connection with the vibrated cables is through the flexible housing J9, which of course trans- It will be understood that I mits no shock or vibration. Itx is therefore 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 an upward movement along the full length of the cloth, with every wave set up, and a downward movement, the upward and downward movements corresponding to the diii'erence,--l

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 transversely across the screen from edge to edge, and follow each other 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. f

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 additional stationaryv sides it inside the rubber strips but are positioned far enough from the screen cloth to prevent contact or wear. The

result is a saving in power and a decrease in the amount of vibration transmitted to the supporting frame. The hinging of the stationary sides permits the screen cloth to be removed with a minimum of work.

The tensional mounting of the cables is an important and probably a necessary element in the production of the wave-like 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 G7 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 flexibility of the springs. This is important, since if a return wave were set up, it would kill the next initial wavetravelling in the op l posite direction at the point where they meet.

While it may be preferable to employ a spring connection between eachend of each cable andthe frame and yoke respectively, as shown in Figure 1, I nd it deslrable under somecircumstances 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 D and let the abutment D engage the abutment A. Or any other suitable abutment means may be -emloyed for maintaining the end of the cables i332 connected to the frame. In such case the springs at the upper end of the cable, the springs G7, may e emplo ed to take care of the shortening and lengt ening 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 throughout 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 limit myself 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 speciically at any given end ofthe cable, ex-

cept so far as I speciically so limit mysel In practice a very satisfacto arrangement is to connect the cables yie din ly to the yoke E and unyieldingly, at their opposite ends, to the frame. My tests have indicated that the yielding connection at the vibration transmitting end of the cable, namely between cable and yoke, is eiective in preventing return vibration or return waves of vibration along the cable.

In connection with the wave-like 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 upand 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 transversely flexible but longitudinally inflexible. I mean a screen which will -iex 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 exible transversely, but is held against longitudinal iexure.

I claim:

1. In a screen, a screen member and a cable extending from end to end thereof and means for maintaining said cable under substantial tension, the screen member being supported upon the cable and being mounted for movement in unison with it, and means for imparting to said cable a wave-like vibration, the crests of the waves of such vibration travelling from end to end of the screen.

i 2. In a screen, a screen member and a' cable extending from end to end thereof and means for maintaining said cable under substantial tension, the screen member being supported upon the cable and being mounted for movement in'unison with it, and means for imparting to said cable a wave-like vibration, the crests of the waves of such Vibration travel ling from end to end of the screen, including an eccentric, means for rotating it, and an actuating connection between the eccentric and the cable.

3. In a screen, a screen member, a plurality of cables extending from end to end there of and means for maintaining said cable under substantial tension and means for imparting a wave-like vibration to said cables, lthe screen member being supported upon said cables and being constrained to movement therewith throughout substantially its entire eiiective area.

4. The structure of claim 3 characterized by means for varyingthe tension upon said cables.

5. The structure of claim 3 characterized by means for maintaining said cables under tension, and means for equalizing the tension upon said cables.

6. The structure of claim 3 characterized by transverse connections between said cables, the screen member being supported upon and held against movement in relation to said transverse connections.

v'i'. In a screen, a normally fixed base, a screen member and means for supporting it lupon said base, said means including a plurality of flexible vibratory actuating members, upon which the screen member is mounted, means for maintaining said members under tension,.means for equalizing the tension upon said members, including a yoke to which said members are secured, said yoke being pivoted upon said base, and means for imparting to said flexible members a generally wave-like vibration.

8. In a screen, a screen member, a plurality of flexible vibratory members upon which the screen member is mounted, means for im-k parting vibration to said vibratory members, transverse connections between said vibratory members Vadapted to prevent flexure of the screen member along axes parallel with said members and means for constraining the Dcreen member to vibration with saidvi- -bratery members and transverse connections,

mounted, means for imparting vibration to' said cables, transverse screen supporting connectionsbetwecn said cables and means for securing them to said cables, including clamps extending about said cables and transverse connections, and yielding elements interposed'between said cables and the clam s.

10. In a screen, a screen member, a lexi le cable upon which said member is supported, means for imparting vibration to said cable and means for maintaining said cable under tension, said tensioning means including a collar about said cable and an enlargement of the end of the cable, adapted to prevent the passage of the cable through the collar.

l1.. The structure of claim l0 characterized by a cable abutment and a yielding member interposed between said collar and said abutment.

12. The structure of claim l0 characterized in that said collar is iiared to a diameter somewhat greater than the normalV diameter of thevcable, the cable being partially unwound, and being provided with a filling or enlargement at said unwound portion, of sufficient diameter to conform generally to the enlarged diameter of the collar.

18. In a screen, a frame, a yoke pivoted to said frame, intermediate the ends of the yoke a plurality of iiexible cables, each of sai cables being secured at one end to said-yoke and at the other end to the frame, a screen mounted upon said cables, and means for vibratingsaid cables.

14. In a screen, a frame, a yoke pivotally secured to said frame, intermediate the ends of the yoke, a plurality of flexible screen supporting members, each of said members being secured atone end to the yoke and at the 'other to the frame, a screen mounted upon said members, means for vibrating the members, and means v`or holding said yoke in parallelism with the general horizontal plane of the screen.

l5. In a screen, a iexible screen member and means Jfor imparting to it a generally uni-directional wave-like vibration, and

means for preventing return or reverse waves 4 said supporting frame and the opposite end of the screen.

16. In a screen, a supporting frame, flexible cables mounted on said frame, a screen mountedzupon said cables, and means for maintaining said cables under tension including an abutment for each said cable, associated with the frame, an abutment mounted upon the cable and a s ring adapted to be compressed between sai abutments, one of.

said abutments including a plurality of removable segmental iange elements.

17. In a screen, a screen member and flexible supporting cables therefor, means for maintaining said cables under tension, and

means for equalizing said tension, said tensioning and equalizlng means including a transverse yoke-and a yielding connection -between said yoke and each of said cables, and

means for imparting Vibration to said cables.

18. In a screen, a screen member and flexible supporting cables therefor, means for maintaining said cables under tension, and means for equalizing said tension, said tensioning and equalizing means including a transverse yoke and a yielding connection between said yoke and each of said cables, and means for imparting vibration to saidcables, said means including an actuating connection with each said cable adjacent its ilexible connection with the oke.

Signed at Hollywoo county of Los Angeles and State of California, this 23rd day of October, 1929.

LORE-N G. SYMONS.

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