US2220106A - Screen cloth and method of making same - Google Patents

Description

Nov. 5, 1940. R. D. HELLER SCREEN CLOTH AND METHOD OF MAKING SAME Filed Oct. 8, 1958 2 Sheets-Sheet l //YVEN7'OR.'

. RICHARD DHELLER,

BY MM 777. Wv'q/LW Arr'm R. D. HELLER SCREEN CLOTH AND METHOD OF MAKING. SAME NOV. 5, 1940.

Filed Oct. 8, 1938 2 Sheets-Sheet 2 b fimw m Q RR m W 1. wm HM W N \m mm T Nm rum mm LN NW0 N Um Wm lmwrm Y 0 Pm 9v MmN MM P9 3 mm K mm Nm L l u 2 n m l T 1 t 1 n" L 1 :II 1 1 n. n .n l n m" u L I h 1 m m" 1|: 3 1 u r Tl r I I- i x m I mm mm M o rm U5 fiYVE/YTOR RICHARD D. HELLER, sh BY EflKM 77 7 ATTY Patented Nov. 5, 1940 UNITED STATES PATENT OFFICE Richard D. Heller, Boise, Idaho Application October 8, 1938, Serial No. 234,015

9 Claims.

This invention relates to an improved type of screen cloth and a method of making the same. An object of the invention is to provide an improved method of making screen cloths which insures relatively long life thereof.

Still a further object of the invention is to provide an improved method of attaching a screen cloth to end bars which will insure a permanent attachment for the life of the screen cloth.

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

In the accompanying drawings, i

Fig. 1 is a perspective view of a loom on which screen cloths are formed;

Fig. 2 is a sectional view of a detail of the loom of Fig. 1 and taken on the line 2-2 of Fig. 3 looking in the direction of the arrows;

Fig. 3 is a longitudinal sectional view of a portion of the loom showing one of the early steps in the carrying out of the method of attaching the screen cloth to an end bar;

Fig. 4 is a view similar to Fig. 3 showing a further step in the method;

Figs. 5 and 6 show successive steps in the method of making the screen cloth and particularly of attaching intermediate strips thereto;

Fig. 7 is an enlarged diagonal view showing the arrangement of parts during one of the final steps of carrying out the method;

Fig. 8 is a plan view of a completed screen cloth comprising my invention;

Fig. 9 is a side view of the screen cloth of Fig. 8;

Fig. 10 is an enlarged side view showing the attachment between the screen cloth and the end bar as well as an intermediate strip attachment between the screen cloth wires;

Fig. 11 is an enlarged plan view of a portion of the screen cloth showing its attachment to an end bar; and

Figs. 12, 13 and 14 are perspective views of alternate forms of end bars.

The method herein disclosed relates particularly to the construction of a complete screen cloth formed of a plurality of parallel substantially straight or non-woven wires preferably made of high carbon Swedish steel known as bright music or piano wires. This type of wire is very hard and tough and consequently has a very long life when operating as a screen cloth, thus making it extremely desirable for this purpose. One of the difiiculties of employing this wire. for screen cloth has been that of attachin it rigidly to end bars and the present method and resulting screen cloth present solutions of this problem.

To construct a complete screen cloth in accordance with my invention a continuous wire -.5 of the above mentioned type is wound upon a loom 20 which may take any desired form, such as disclosed in my Patent No. 2,068,675, dated January 26, 1937.

As illustrated in Fig. 1 of the drawings, the 10 loom 20 is formed by a base or stand 2| upon which is journaled a rotatable frame 22 having at opposite ends removable threaded pipes 23, 23. The pipes 23, 23 are removable so that different thread spacings may be realized which determine the spacing of the parallel wire strands on the finished screen cloth. This makes for a simple and effective gauge to determine the gauge of the screen cloth.

To form the complete screen cloth an endlesssteel wire 24 of the type above mentioned is wound about the grooves of the threaded pipes 23 by rotating the rotatable frame 22 to form a plurality of parallel substantially straight strands, as illustrated in Fig. 1 of the drawings.

After the desired number of strands have been wound. upon the loom 20 the frame 23 is locked in a substantially horizontal position by any desired means, for example, by placing a support under one end of the frame 22. With the frame 22 in a substantially horizontal position a channel member 25'is placed upon the frame 22 near one of the pipes 23. This channel member 25 has a depth just slightly less than the distance between the frame 22 and the strands of wire 24. The bottom, inside and top surfaces of the channel member 25 are then covered by a strip of heat resisting material 26 which is antagonistic to liquid solder, such as sheet asbestos, the purpose of which is more fully described hereinafter.

In the bottom of the channel member 25 and resting on the material 26 is an electric strip heater 21. Above and resting directly on the strip heater 21 there is placed an end bar 28 which is to be attached to the strands of the steel wire 24. The upper surface of the end bar 28 is preferably roughened as by diagonal grooves 29, as illustrated in Fig. 12 of the drawings. In lieu of this particular form of end bar I may provide an end bar I28, with a longitudinally extending groove I29, as seen in Fig. 13 of the drawings, or an end bar 228 with a longitudinally extending groove 229 and transversely extending grooves 230 spaced apart equal to the spacings of the successive strands of the wire 24, as illustrated in Fig. 14 of the drawings.

With the above described parts in the positions illustrated in Fig. 3 of the drawings, a pair of 5 strips of wire solder 30 are laid upon the strands of the wire 24 directly above the end bar 28 and extending the full length of said end bar 28. Electric current is then supplied to the strip heater 21 which heats up and in turn heats the end bar 28 which, after a required length of time, melts the solder strips 30. By referring to Fig. 7 of the drawings it will be seen that the asbestos material 26 running along the top surfaces of the channel member 25 will act to confine this 15 liquid solder against lateral movement away from the end bar 28 because this material is antagonistic to liquid solder. That is, liquid solder will not attach to it or will not run'over it readily.

To confine the liquid solder against longitudinal movement away from the bar 28 there is a block 3| of heat resisting material which is antagonistic to solder, such as asbestos, placed at each end of the end bar 28 in direct contact therewith, and upon the strip heater 21, being confined between the side walls of the channel member 25. In other words, the top surface of the end'bar 28 is completely surrounded by asbestos material, or the like, which is not only resistant to heat but also confines the molten solder in a lake on top of the end bar 28.

After the applied solder has been completely liquified by heat derived from the end bar 28 which, due to the heating thereof, will insure a bonding with the solder when it cools thereafter, the liquid solder forming the mentioned lake will completely cover the portion of the strands of wire 24 directly above said end bar 28, or in other words, passing through the lake of liquid solder. Under these circumstances, a pair of strips 32, 33 of metal plate such, for example, as tin plate, are

laid on top of the strands of wire 24 above the end bar 28. The right hand edge of the strip 33, as viewed in Figs. 3, 4 and 7 of the drawings, is preferably in alignment with the right hand edge 5 of the end bar 28. The left hand edge of the strip 32 preferably extends slightly to the left of the left hand edge of the bar 28 for a purpose hereinafter described in full detail.

It has been found in practice that when the [50 strips, such as the strips 32 and 33, are laid in position as above described, they tend to attract a considerable portion of the liquid solder by virtue of capillary attraction and in some cases it has been found that this capillary action robs .55 certain areas of the bar 28 of solder which, un-

less corrected, will result in one or more of the strands of wire 24 becoming loose. The lateral spacing of the strips 32 and 33 is therefore very important because it acts in the nature of a window whereby the operator can see if solder has been attracted away from any particular area and, if so, additional solder is applied to insure a complete bond between all of the strands of wire 24 and the end bar 28.

In practice it is preferred that sufficient solder be applied between the strips 32 and 33 so that upon cooling the exposed portions of the strands of wire 24, as illustrated inFig. 7 of the drawings; will be completely embedded in solid solder. .7 After the above described operations have been performed the current is turned off from the strip heater 21 and the parts allowed to cool, whereupon the solder will solidify and effect a rigid bond attaching the end bar 28, the strips 32 and 75 33 and the contacting portions of the strands of wire 24, also leaving a smooth glossy surface of solder between the strips 32, 33 due to the fact that the solder is heated from the end bar 28 rather than being applied by a soldering iron which inevitably leaves tracks.

After the parts have cooled sufiiciently, as above described, the channel member 25 is moved to a position adjacent the opposite end of the rotatable frame 22 or to some intermediateposition depending upon the length of the desired screen cloth and the above described operations are repeated to attach another end bar 28 to the ultimate edge of the completed screen cloth.

Thereafter, the rotatable frame 22 is rotated 180 degrees and the above described operations repeated. at each end of the ultimate screen cloth.

In addition to attaching the and bars- 28 to the strands of wire 24 said strands are preferably connected intermediate said end bars 28 at a plurality of positions, for example, as illustrated in Figs. 8 and 9 of the drawings, to provide bearing areas with the frame of a screen deck, for example, as disclosed in full detail in my application Serial No. 234,014, filed of even date herewith, wherein the screen cloth herein disclosed is also disclosed and claimed.

To effect these intermediate connections the channel member 25 with the heat resisting material 26 and heater strip 21 as well as with the end blocks 3| are positioned at the desired intermediate position on the frame 22, but in place of the end bar 28 there is substituted a slightly thinner plate 34, the top surface of which is provided with an anti-flux'to prevent solder attaching to it, such, for example, as ordinary stove blacking.

Upon the plate 34 and under and in direct contact with the strands of wire 24, there is placed a strip of metal 36, such as tin plate, directly above which and on top of the strands of wire 24 is placed a strip of solder 35, as best illustrated in Fig. of the drawings. The strip heater 21 is then supplied with current which, after appropriate time, melts the solder 35, after which another strip of metal 31, such as tin plate, is applied over the strip 36. Thereafter, the current to strip heater 21 is shut off and the parts allowed to cool, resulting in the solidifying of the solder when the consequent rigid attachment of the strips 36 and 31 and the strands of wire 34.

The desired soldering operations having been completed the channel 25, strip heater 21, heat resisting materials 26 and 31 are removed from the frame 22 and the strands of the wire 24 are clipped along the outer edges of the strips 32. It Y is thus evident that in the form of the looms disclosed in Fig. 1 of the drawings, two screen cloths will be made at a time.

To effect a further securing of the strands of wire 24 to the end bars 28 said bars and parts of depressible material 48, such as strip rubber, is

pressed along and over the metal strip 36 or 31, depending upon which is to be in contact with the supporting portion of the vibrating screen deck, as fully disclosed in my co-pending application above mentioned, the edges of which material 40 Thereafter, adjacent the inner edge of each extend laterallybeyond theedges of the strip 36 or 31, and are pressed between the adjacent strands of wire24, as clearly illustrated in Fig. 10 of the drawings. i

It may be stated generally that the strips 39 and 4|! perform three important functions. In the first place, they act as resilient cushion means between the screen cloth and the bearing areas of the deck of the vibratory screen. In the second place, they progressively dampen the individual vibration of each strand of wire 24 between points of anchorage to an end bar 28, or to the strips 36-3'|, and thereby prevent said individual strands becoming fatigued and broken in operation. In the third place, they prevent material becoming caught in this portion of the screen cloth where there is a minimum of vibration or, in other words, no individual vibration of the individual strand of wire 24, as distinguished from its vibration in unison with the entire vibratory deck.

By referring to Figs. 8 to 11, inclusive, of the drawings, it wil be seen that the complete screen cloth is formed by a pair of spaced end bars 28, 28 to which are rigidly attached the ends of a plurality of parallel substantially straight strands of high carbon steel wire, such as bright music or piano wire. The parallel strands are attached together intermediate the end bars 28 by the soldered strips 3631 of which there are three illustrated in the drawings, though, of course, the number may be varied as desired.

It will be evident that between any two points of anchorage an individual strand of the wire 24 is free to vibrate as an individual unit independent of the complete vibration of the whole screen cloth with the deck upon which it is mounted.

While the screen cloth is particularly designed ,6 for use with a vibratory type of screen and is designed particularly to withstand the severe stresses and strains incident to this type of screen, it is, of course, manifest that the cloth may be used with other types of screens, such as 45 stationary or trommel screens.

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 50 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. The method of forming a screen cloth with an attached end bar which comprises positioning an end bar along an ultimate cloth edge in contact with said cloth, placing solder on the cloth above the end bar, placing heat resisting material on each side ofthe end bar and under the cloth in contact therewith, and heating the solder to melt it and attach the screen cloth and bar.

2. The method of attaching a screen cloth and end bar which comprises placing an end bar under and in contact with a screen cloth, soldering said screen cloth to and between said end bar and two longitudinally extending laterally spaced metal strips one of which extends laterally beyond said end .bar with an edge of said screen cloth, and bending over the laterally extending portion of said one strip and the adjacent portion of said screen cloth.

3. The method of attaching a screen cloth and end bar which comprises placing an end bar under and in contact with a screen cloth, soldering said screen cloth to and between said end bar and a longitudinally extending metal strip which extends laterally beyond said end bar with an edge of said screen cloth, and bending over the laterally extendingv portion of said strip and the adjacent portion of said screen cloth.

4. The method of attaching an end bar to a screen cloth which comprises supporting a strip heater and an end bar in a channel support, insulating the inside and top of said channel with heat resisting material, pressing a screen cloth against the end bar and heat resisting material on top of said channel, applying solder to said screen cloth above said end bar, and heating said end bar from said strip heater to meet said solder and thereby attach said end bar and screen cloth while said heat resisting material confines the molten solder to the desired area.

5. The method of attaching an end bar to a screen cloth which comprises supporting a strip heater and an end bar in a channel support, insulating the inside and top of said channel with heat resisting material, pressing a screen cloth against the end bar and heat resisting material on top of said channel, placing solder on said screen cloth above said end bar, heating said end bar from said strip heater to melt the solder, and applying a metal strip above said solder, said solder on cooling attaching said end bar, screen cloth and metal strip together.

6. The method of attaching an end bar to a screen cloth which comprises supporting a strip heaterand an end bar in a channel support, insulating the inside and top of said channel with heat resisting material; pressing a screen cloth against the end bar and heat resisting material on top of said channel, placingsolder on said screen cloth above said end bar, heating said end bar from said strip heater to melt said solder, applying a pair of laterally spaced metal strips above said end bar, and adding any necessary solder between said spaced strips to insure a complete attachment between the strips, screen cloth and end bar when said solder cools.

7. The method of attaching an end bar to a screen cloth which comprises supporting a strip heater and an end bar in a channel support, insulating the inside and top of said channel with heat resisting material, pressing a screen cloth against the end bar and heat resisting material on top of said channel, placing solder on said screen cloth above said bar, heating said end bar from said strip heater to melt the solder, applying a metal strip above said end bar which extends over one edge thereof with an edge of the screen cloth, allowing said solder to cool to attach said end bar, strip and screen cloth, and bending over the portion of said screen cloth and strip which extend beyond said end bar.

8. The method of making screen cloths which comprises wrapping a continuous wire about a loom to form a plurality of ultimate screen cloths, supporting an end bar near each ultimate edge of each screen cloth, placing a metal strip above each end bar which extends laterally beyond one edge thereof, attaching each end bar and metal strip to the screen cloth by a heating action which melts material and binds the screen cloth, metal strips and end bars, severing the screen cloth near to but slightly beyond the edge of each end bar, and bending over the portion of each screen cloth and metal strip extending beyond an end bar.

9. The method of attaching a screen cloth and end bar which comprises bringing said screen cloth and end bar into contact at an area of attachment, surrounding the area of attachment with heat resisting material having proper- RICHARD D. HELLER.

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