US2283877A - Screen - Google Patents

Description

May 19; T942.

.3. D. HELLER D SCREEN F iled Oct. 8, 193a 4 Sheets-Sheet 1 f/Yl/E/YTOR RICHARD D. HELL-E R,

84) 19} 1942;; I RID. HELLER 2,283,877

7 SCREEN 'Filed Oct. 8,1938 4' Sheets-Sheet 2 179m? I0 f/vvg/v TOR.

RICHARD D. HELLER, BY

- ATT Y.

ay1 R. D. HELLER 2,2 3,817

7 v SCREEN.

Filed Oct. 8, 1938 i 4 Sheets-sheaf, s

JWENTOR: RICHARDDHELL ER, BY %A, 7349p,

ATT'Y.

May 19, 1942. R D. HELLER SCREEN Fi lred Oct. 8, 19:8

4 Sheets-Sheet v 4 f/WE YTOR v RICHARD D. HELLER;

m rm m v Mm E Q om mw WNW o MKS a g Q 5 Mi m 52 rw. Fm fm mm Wm mm\1 m H/wm m F Jr .JF w k PU Patented May 19, 1942 UNlTED STATES PTE OFFICE 7 Claims. (01. 209-400) This invention relates to a new and improved screen, particularly of the vibratory type, and

v more specifically, to a new and improved means for attaching the screen cloth to the deck and to a new and improved form of screen cloth. An object of the invention therefore, is to provide new and improved attaching means for attaching a screen cloth to a deck.

Another object of the invention is to provide a new andimproved screen cloth. 7

Still a further object of the invention is to provide a new and improved screen construction, particularly of the vibratory type. 7

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the accompanying drawings,

Fig. 1 is a side elevational view of the screen comprising my invention;

Fig. 2 is a front elevational view of said screen;

Fig. 3 is a transverse sectional view taken on the line 3-3 of Fig. 1 looking in the direction of the arrows;

Fig. 4 is an enlarged transverse sectional view similar to Fig. 3 except that it shows only the deck, screen cloth and means for attachin the screen cloth to the deck;

Fig. 5 is a plan view of a segment of the screen cloth;

Fig. 6 is a sectional View of a segment of the screen cloth; and

Figs. '7, 8 and 9 show alternate forms of the end bars of the screen cloth.

In a vibratory type of screen, particularly of the type energized from mixed or alternating current of 60 cycle frequency or from rectifiers, in which the frequency of vibration is relatively high, such as 3600 vibrations per minute, or in excess thereof, as derived from a source of commercial current of 60 cycle frequency, there is a considerable whipping action imparted to the screen cloth which tends to reduce the life of said screen cloth not only by virtue of the whipping action'which tends to break the cloth at its point of anchorage, but also because of the wearing at positions where the wires of the creen cloth contacts the deck of the vibrating screen.

In the invention herein disclosed an essentially new type of screen cloth is provided for a high frequency vibratory screen in which the life of the screen is materially increased due to the fact that very high carbon steel wires, such as music or piano wires, make up the screen cloth and further, at the points of bearing between the screen longitudinally cloth and the deck, resilient rubber or similar bearing means are provided.

Referring particularly to Figs. 1, 2 and 3 of the drawings, there is seen a screen comprising a main frame In comprising a steel casting which includes longitudinally extending side members H, II connected together at their opposite ends by transverse cross members l2, l2. Extending spring bars l3, IS the ends of which are attached in boxes l4, l4 formed as integral parts of the side members I l, l l, the bars l3 being clamped in said boxes M by clamp screws l5, 15.

To the centers of said spring bars l3, l3 there are clamped castings l6, 16 which are rigidly attached together by a transversely extending I- beam 11 by means of riveted plates l8, I8. The clamping of each casting IE to the centers of the cooperating spring bars I3 is effected by a clamp screw I9. Rigidly attached to each casting I6 is a bracket 20 which carries an armature 2| of a vibratory electro-magnetic motor 22, said armature 2| being formed of laminated sheet steel. Cooperating with the armature 2| to form the complete motor 22 is a U-shaped core 23 of laminated sheet steel'which is carried by a bracket 24, which bracket 24 is in turn adjustably mounted upon a U-shaped bracket 25 the ends of which are attached to a side member I l.

Each leg of the U-shaped core 23 carries an energizing field coil 26 adapted to be energized with pulsating, mixed or alternatin current by way of conductors 21.

To support the screen flexibly I provide four hang rods 28 attached to the main frame Ill by means of I-bolts 29, the upper ends of which hang rods 28 are flexibly attached to a superstructure 30. The flexible attachment of each rod 28 of the superstructure 30 i provided by attaching means comprising a base3l, a cap 32 and a coil spring 33 interposed between said base and cap. It is manifest that the two lock nuts 34 on the upper end of each hang rod 28 will transmit the load from said rod to the cap 32 which would then be supported from the base 3| through the interposed coil spring 33. This prevents any damage being done to the superstructure by virtue of vibrations which may be present in the main frame It.

It may be stated that the structure of the screen and its general mode of operation, insofar as above described, is disclosed and claimed in the patent to J amcs A. Flint, No. 1,846,326, dated along the side members II, II are February 23, 1932, for an Electric reciprocating motor.

Mounted upon and rigidly attached to the castings I6 to vibrate therewith is a deck 35. The deck 35 is formed by a pair of longitudinally extendin channel members 36, 36 the bottoms of which are rigidly attached together by cross channels 31 of which there is one at each end and preferably two intermediate the ends. The tops of the channel members 36 are also attached together by three spaced angle members 38.

Extending longitudinally of the deck and supported in notches in the channels 31 to which they are welded is a plurality of upstanding ribs 39 having channel tops 40 adapted to receive longitudinally extending wood strips M which bear against the screen cloth 42, as hereinafter described in complete detail.

Referring particularly to Figs. 4 to 9, inclusive, of the drawings, it will be seen that the screen cloth 42 comprises a pair of end bars 43, 43, preferably rectangular in shape, though other shapes may be employed, said end bars 43 being made of steel or iron.

Extending between the said end bars 43 is a plurality of parallel wires 44 which are preferably made of high carbon steel, such as bright piano or music wire. It is to be noted that these parallel wires 44 are straight or substantially straight, and when this expression is used in the claims it is meant to distinguish between the common screen cloth in which the strands are interwoven transversely and longitudinally whereby substantially each strand forms a zigzag path or is crimped at each contact area with another strand.

To attach the wires 44 securely to each end bar 43 said end bar 43 is preferably provided with a roughened surface, such as the diagonal grooves 45 seen in Fig. 7 of the drawings; the longitudinal notch 46 seen in the end bar I43 in Fig. 8 of the drawings; or the combination of a longitudinal notch 41 and transverse grooves 48 seen in the end bar 243 in Fig. 9 of the drawings. It is, of course, to be understood that any form of the end bars, as illustrated in Figs. 7, 8 and 9 of the drawings, may be employed.

The wires 44 are soldered or otherwise adhesively attached to the end bars 43, I43 and 243 preferably in the manner as described in complete detail in my application, Serial No. 234,015 filed of even date herewith.

To insure the secure attaching of said wires 44 with said end bars 43, I43 or 243 a pair of tin strips 49 and 50 are placed over the ends of the wires 44 and are attached to the solder above mentioned, the extreme ends of said wires 44 being bent over the outer corner of the end bar 43 with the outer end of the tin strip 50 to contact the outer edge of the associated end bar 43, as clearly illustrated in Fig. 6 of the drawings.

Intermediate the end bars 43, 43 the wires 44 are preferably attached together through the longitudinal length of the screen by top and bottom tin strips I which are attached together and to said wires 44 by solder. The tin strips 5I are preferably so positioned that the will be directly above the aforementioned wood strips 4 I.

Adjacent each bearing area between the screen cloth 42 and the deck 35 I provide rubber or other depressible material cushion means which performs three functions, hereinafter set forth.

Adjacent the positions of attachment of the wires 44 to the end bars 43 are strips of rubber 52 or any other similar material which extend longitudinally the entire length of the screen cloth and are compressed against the wires 44 so as to extend on both sides of them, being attached to said wires as by rubber cement. Rubber strips 53 are also laid over one of each of the tin strips 5I which is to bear against a wood strip 4I thereby forming a cushion between the wood strip 4I and the tin strip 5|. The rubber strip 53 extends laterally beyond the extremity of the associated tin strip 5| and is compressed between the wires 44 adjacent each edge of said tin strips 5 I.

The three-fold function of the rubber strips 52 and 53 is as follows. In the first place, these rubber strips provide a resilient cushion between screen cloth 42 and the associated bearing portion of the deck 35 thereby preventing undue wear of both the deck and the screen cloth. In the second place, these rubber strips are, of course, positioned at areas on the screen cloth at which there is no substantial independent vibration of the wires 44, said wires 44 being free to vibrate individually between any two bearing areas of said screen cloth 42 and the deck 35. Consequently since the rubber extends beyond the point of rigid connection between an end bar 43 and a wire 44, or a tin strip 5I and the wire 44, this rubber will progressively dampen the vibration of each individual wire 44 as it progresses towards its point of rigid attachment thereby reducing appreciably the tendency of the wire to break 011 at its point of rigid attachment to a bar 43 or tin strip 5| under the influence of the relatively high frequency vibration of the vibratory screen. In the third place, since there is a very small amount of vibration of each wire 44 adjacent its point of attachment to an end bar 43 or a tin strip 5I the wires 44 are not able to clear themselves of any material which tends to become lodged between adjacent wires due to this lack of vibration and this rubber along this area prevents material being caught between adjacent wires or strands 44 and thereby becoming lodged in the screen cloth 42.

To provide for the attachment of the screen cloth 42 to the deck 35 and for its adjustable tensioning I provide a novel attaching means which is designed particularly to aid in maintaining the wires 44 in attachment with the end bars 43. As clearly seen by reference to Fig. 4 of the drawings, adjacent the left hand side of the deck 35 there is a longitudinally extending channel member 54 the top flange of which is pivoted in a longitudinally extending groove 55 formed by the top flange of the channel member 36 and a notched longitudinally extended member 56 welded to the upper corner of said channel member 36.

Adjacent the bottom of the channel 54 and distributed along the length thereof is a plurality of holes adapted to receive tensioning bolts 51 which extend through apertures in the channel 36 and receive adjusting nuts 58 provided with bearing sleeves 59 which extend through the receiving apertures in the channels 36. A washer 60 is also preferably positioned between the outer face of the channel 36 and the head of each nut 58. Another washer BI is also preferably placed between the head of each bolt 57 and the inner face of the channel member 54.

The bottom flange of the channel 54 carries a downwardly extending channel 62, the inner flange of which carries a bearing plate 63 to in- Crease the bearingarea in contact with the rubber strip 52 which bears against said plate 63 and the inner flange of said channel 62.

Extending longitudinally substantially the full length of the channel 62 and in the corner'adjacent the inner flange is a ledge 64 formed by a longitudinally extending rectangular bar which is welded at the position indicated. Carried on the opposite or outer flange of the channel 62 is an abutment 65 formed by a longitudinallyextending bar which is spaced from the outer corner of said channel 62 and is welded to said outer flange thereof.

As is clearly illustrated in Fig. 4 of the drawin'gs, the outer end of an end bar 43 projects under the abutment 65 and rests on the bottom of the channel 62 which is, of course, in an inverted position. The top inner edge of the bar 43 abuts the inner flange of the channel 62, and said bar 43 at a position adjacent said top inner edge rests on the ledge 64. It will be seen that the structure defined locks the end bar 43 to the attaching and tensioning mechanism after the end bar 43 is inserted in place.

Furthermore, it is to be noted that the abutment 65 cooperates with the end bar 43 to effect a clamping action on the wires 43 and the tin strip 56 to prevent any of the wires 44 being pulled loose from the end bar 43.

As a further action to prevent any wire 44 being pulled from an end bar 43 it is to be notedthat the wire 44 bends as it leaves the end bar 43 and bends in a direction to force said wires 44 into engagement with the bar 43. In other words, this results in the wires 44 being at least partially wrapped around the bars 43 which is carried even further at the outer ends of said wires 44, thereby resulting in a very secure connection between the two, particularly when supplemented by the aforementioned attaching solder and tin strips 49 and 50.

At the right hand end of the deck 35 the screen cloth 42 is attached in a manner quite similar to that above described by an attaching bracket indicated generally by the reference character 66, except for the fact that the bracket 66 is not adjustable but is fixed to the channel 36, and the structure of which is obvious from the above description of the adjustable attaching means and by reference to said Fig. 4 of the drawings.

It may additionally be mentioned that to reinforce the deck 35 there is provided a plurality of spaced outward extending webs or fins 61 which provide vertical rigidity to the channel members 36.

In the operation of the screen comprising my invention alternating, mixed or rectified, pulsating current is supplied to the vibratory motors 22 which will cause vibration of the deck 35 relative to the main frame II] in a manner well understood in this art and more completely described in the above mentioned patent to James A. Flint. This vibration will be at a relatively high frequency, such as 3600 vibrations per minute though, of course, other frequencies of vibration are contemplated.

Under the influence of this relatively high frequency of vibration the individual wires 44 of the screen cloth 42 vibrate as individual units between the points of bearing between them and the deck, for example, between each of the rubber strips 53 and between each rubber strip 53 and a rubber strip 52. As a consequence, blinding of the screen cloth 42 is substantially prevented because this individual vibratory motion of each portion of a wire 44 in addition to the entire vibratory motion of the deck 35 will clear the screen cloth 42 of any material which tends to'adhere thereto. As a consequence, the screen cloth of my invention is extremely desirable in combination with a relatively high frequency'v'ibratory type of screen, though its use is not entirely so restricted.

As previously mentioned, to prevent undue wear of the screen cloth 42 or of the deck, cushion means in the form of rubber'strips 52 and 53 or any other appropriate cushioning material is provided and interposed-between the screen cloth 42 and each point of bearing or contact with the deck 35. These rubber strips 52 and 53 additionally prevent breakage of the individual wires 44 due to their vibration by virtue of the dampening of the vibration thereof adjacent their'points of rigid attachment either to end bars 43 or to tin strips 5!.

Still further, these rubber strips 52, 53 prevent blinding of the screen at the areas where there is no appreciable individual vibration of the wires 44 as distinguished from the vibration of said wires due to their attachment to the vibratory deck 35. The wood strips M are preferably provided because there is inherently some wearing at these bearing areas and as said wood strips 4| become worn they can be replaced.

Another important advantage of this type of screen cloth lies in the fact that it may be made of veryhigh carbon steel such as music or piano wire. This steel wire has a very long life even when used to screen abrasive materials and due to the fact that the strands of wire 44 are substantially straight, as distinguished from crimped or zigzag wire found in woven screen cloth, it is possible to employ this relatively stiff, high carbon steel wire.

It will, of course, be understood that material will be fed to the screen at its upper end, as viewed in Fig. 1, and will travel downwardly over said screen under the influence of gravity aided by the vibratory motion of the deck 35, as well as the superposed individual vibration of the free portions of the wires 44. The material which is of sufficiently small size to pass through the screen cloth 42 will do so and will be discharged through the bottom of the screen while the oversize material will discharge over the lower end of said screen cloth 42.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I therefore wish not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

1. In a screen, the combination with a frame, of a screen, means for attaching said screen to said frame comprising a channel having .a ledge in one inside corner adjacent a channel flange and an abutment on the inside of the opposite flange and spaced from the other corner, and an end bar on said screen adapted to extend under said ledge at one edge and rest on said abutment at the other edge, said screen extending from said end bar adjacent the said ledge.

2. An attaching and tensioning means for a screen cloth comprising a channel member, a ledge formed in one inner corner thereof, and. an abutment spaced from the otherinner corner and on one of the flanges of said channel.

3. In a screen, the combination with a frame,

of a screen cloth, an end bar attached to said screen cloth, said screen cloth being bent over the outer edge of said bar, means for attaching said screen to said frame comprising a channel having a ledge in one inner corner and an abutment spaced from the other inner corner and on one of the flanges of said channel, said end bar extending over and in contact with said abutment at its outer edge to clamp said screen cloth between said bar and said abutment and extending under said ledge at its inner edge.

4. In a screen, the combination with a frame, of a screen cloth, means for attaching and tensioning said screen cloth comprising a channel, an abutment spaced from the bottom of said channel and extending inwardly from one flange thereof, and a bar attached to said screen cloth adapted to extend between the channel bottom and abutment and in contact therewith at one edge with the opposite edge in contact with the other channel flange.

5. An attaching means for a screen cloth comprising a channel member, a ledge in one inner corner thereof adjacent one flange of the channel and an abutment on the other flange of the channel extending inwardly thereof and spaced from the channel bottom.

6. A screen cloth comprising an end bar, parallel wires permanently attached near their ends to said bar while extending therebeyond, a metal strip permanently attached to said bar and wires and extending therebeyond and bent over said bar with the ends of said wires, and metal strips removed from said bar and attaching said wires permanently together.

7. A screen cloth comprising end bars each having a rough top surface, parallel wires permanently soldered to said top surfaces, and a pair of laterally spaced metal strips attached to and above each end bar by said solder, one of each of said pair of metal strips extending beyond the end bar and bent over with overextending wire ends to insure a permanent attachment between said wires and end bars.

RICHARD D. HELLER.

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