US2086551A - Trommel - Google Patents

Description

R. D. HELLER July 13, 1937.

TROMMEL Filed Oct. 18, 1935 2 Sheets-Sheet l July 13, 1937'.

R. D. HELLER TROMMEL Filed Oct. 18, 1935 2 Sheets-Sheet 2 H) Richard D. Hellir gm A. W

Patented July 13, 1937 UNITED STATES PATENT OFFICE TROMMEL Richard D. Heller, Boise, Idaho Application October 18, 1935, Serial No. 45,554

My invention relates to trommels or screens for the purpose of classifying dry granular materials, as in mining operations, but its field of usefulness is not so limited, and it may be used wherever it is desired to separate line material from coarser material, particularly where the material is formed of comparatively hard granules.

The present invention is an improvement over the invention disclosed and claimed in my application Serial No. 727,897, filed May 28, 1934.

In the previous form of my invention, disclosed in said application, some difficulty was encountered in maintaining proper tension on the wires, all of which were originally pretensioned identically and therefore stretched uniformly and maintained in parallelism, by reason ofbending of the cross bars to which all the wires were secured, and by reason of unequal application of tension to the wires to retension them. Accordingly one of the objects of this invention is to provide means whereby the wires may all be equally tensioned again to restore each one of them individually and in relation to the others to the pretensioned relationship or condition, and to provide means such as these which are capable of accomplishing an even, yielding tension on all the wires.

A further object is to simplify the method of replacing worn screens.

One of the difiiculties in all parallel wire screens lies in providing a construction which will permit them to vibrate freely, throughout the length which is exposed to contact with the material, so that they will clwn themselves, and 'yet to prevent passage of small bits of material between the wires and the framework, 'or at the iunction of the wires with the framework, thus to dampen vibration,--to clog or spread the wires, or otherwise to interfere with the proper functioning of the machine. Accordingly it is a further object of my invention to devise means cooperating between the frame and the wires mounted thereon, which will not damp vibration of the wires throughout their entire exposed length, and which will prevent entrance of materials between the wires and the frame.

More specifically it is an object to provide a resilient member, engaging the wires inwardly of their anchorage to the cross bars, which will prevent passage-of material between this resilient member and the wires, which will not impede vibration of the wires substantially from one point of anchorage to the one at the opposite end, and

10 Claims. (01. 209-400) which will maintain proper spacing of the wires at all times. I

It is a further object to reinforce the wires and furtherto impede movement of bits of material between the wires running parallel to and adjacent to the edge of the openingthrough which the materials pass, the screen.

These and other objects will appear as this specification progresses.

My invention comprises the novel trommel and the novel parts thereof, alone and in combination, as shown in the accompanying drawings, described in this specification, and as will be more particularly pointed out by the claims which terminate the same.

In the accompanying drawings 1. have shown my invention embodied in illustrative forms as now'preferred by me.

Figure 1 is a side elevation of a three-section trommel, with parts broken away.

Figure 2 is an end view of such a trommel.

Figure 3 is an enlarged section on the line 3-3 of Figure 1, and Figure 4 is a similar view showing a modified arrangement.

Figure 5 is a side elevation of a two-section trommel of somewhat modified form from that shown in Figure 1.

Figure 6 is a side elevation of one of the anchorages for the wires, and Figure 7 is an elevation looking down on the same, showing exaggeratedly the manner in which vibration is permitted in the wires. 9

In general the trommel consists of a polyhedral cylinder, set preferably at an incline, and rotatable, whereby materials entering at one end will be lifted and dropped repeatedly, and will slide over each screen as the trommel rotates, and will be worked down toward the lower end, the screens being formed of parallel tensioned wires set in general parallel to the axis of rotation, so that as the trommel rotates, the fine material. of a size to pass between the wires, will pass between them, and larger material will remain inside the trommel, being discharged at the lower end.

Thus in Figures 1 and 5 the rotative frame is made up of corner bars ll joined by end'bars II and at intervals by cross plates i2, ll, it and I! to leave rectangular openings II, II and it, through which the screened material passes. The whole frame is supported by spiders is upon a rotative shaft l. The means for mounting and supporting the trommel, and the classifying bins into which the screened material drops. are not which opening is closed by illustrated, but by way of example reference may be made to the structure shown in my previous application, referred to above.

The wires, generally designated by the numeral 2, are permanently secured, as by welding or soldering, to end bars 20, about which they are wrapped, as may be seen in the large scale view,

Figure 6. Unless, of considerable strength, these end bars will bend when the wire is retensioned, but by engaging the inner edge of each end bar 20 with an upstanding transverse shoulder 30, which is carried by the rotative frame,the end bar is supported throughout its entire length, and thus cannot bend, and therefore holds the wires in the same relationship that they were when first secured to the end bars. The wires may be of a length to extend across only one opening, as shown in Figure 1, or of a length to extend from end to end of the frame, across two or more openings, as shown in Figure 5. In the form shown in Figure l the shoulder 30 upon the plate ii is fixed to the latter, as by bolts 3|, but the shoulders 30a; and 30b are part of a plate 32 which is slidable lengthwise of the frame, being guided on bolts 3m, and likewise shoulders 30c and 30d are siidabiy mounted upon a plate 32, and the shoulder 304: forms part of a plate 33 which rests upon the plate l2. and which has secured toit bolts 34. Springs 35, between nuts 36 on the bolts 34 and the shoulder plate Ii, serve to draw all the wires tight, and to maintain them tensioned as they were in their original pretensioned condition. In order to hold the several end bars 20 against their respective shoulders 30, 30a, 301), etc., clamping or hold-down plates 31, 31m, 311; and 310 may be provided, these being held down by the bolts 3|, Ila, etc. The clamping plate 310 is held down by bolts He received in an overhanging flange of plate 33,

so that the latter is not guided from the frame except by the bolts 34.

Preferably the wires 2 do not lie close to the plane defined by the corner angles 10; that is to say, there is no attempt made to keep the wires in the plane of each opening. Instead I have found it preferable to outline each opening with upstanding bars 40 which are of a height to lie just below the normal plane of the wires when stretched, and this space and a little more is occupied by a resilient strip of rubber or the like,

indicated at 4. The frame thus built up lies inwardly of the points of anchorage of the several wires, and also along each side of the opening, the wires at the sides of the opening lying.

in contact with the rubber strips 4 throughout their length, as seen in Figures 1 and 5. The rubber strips 4 serve in a sense as bridge members, the wires being slightly deflected by them to an extent sufficient to press the wires into the rubber, as may be seen in Figure 6. In consequence no material can pass between these wires and the rubber strips 4. By using, live resilient rubber the tendency of the wires to vibrate from their points of anchorage, as is illustrated in Figure '7, is but little, if any, dampened by the rubber strips 4, with the result that the wires vibrate freely, orsubstantially so, at the point where they emerge into the space defining any given opening, whereas if the wires were anchored or dampened at this edge there would importance to insure that the wires be so mounted as to vibrate freely at all points where they may come in contact with the materials. and that a zone of reduced or minimum vibration, if there be any, be outside of the screening opening.

Various means may be employed to vibrate the wires, or to insure their vibration. Reliancemay be placed wholly upon the action of the materials sweeping and sliding down over the wires.

or resiliently mounted picks 5 may be employed, as in my former .application, the points of these piclm engaging each individual wire in turn as the trommel rotates, and serving to set itinto vibration.

As may be seen in Figure 5, the wires may be of a length to extend from end to end of the rotative frame, but in such cases it is preferable to hold the wires down to the frame at intermediate points, and to this end I may provide the clampingplates '8 and 60 engaging each'set of wires at an intermediate point, to prevent of which are equally tensioned, can not bite into the longitudinally extending rubber strip 4 to quite the same extent that they do passing over the'narrow width thereof at each end of the screening opening; hence in order toprevent passage of large material or its lodgment between the wires, thus to clog the screen, I may increase the number of wires at the sides of eachscreen. Thus, for example, as may be seen in Figure 3, the wires may be laid in several layers at the side edge, creating a zone close to the edge which is yet of wire and vibratory, but more dimcult for materialsv to enter or pass through. As seen'in Figure 4, a similar result may be accomplished by doubling the number of wires in a given transverse space.

The manner of using the screen will be evident,

and its advantages have been pointed out'hereof, whereon the wires rest and into which the wires are pressed to prevent escape of materials between the wires and the frame.

2. In a screen for a trommel, a frame defining an opening, a plurality of parallel tensioned wires extending across said opening, means disposed on said frame outwardly of the opening to anchor the ends of the wires and to maintain them under tension, to vibrate, and strips of live rubber extending transversely of I the wires, upstanding from the frame to above the level of the wires, inwardly of the anchoring means, and into which the wires are pressed, but yieldable to such vibration, yet preventing escape of materials between the wires and the frame.

3. In a screen for a trommel, a frame defining an opening, a plurality of parallel tensioned wires extending across said opening, means disposed on said frame outwardly of the opening to anchor the ends of the wires and to maintain them under tension, to vibrate, strips of live rubber disposed inwardly of the anchoring means and extending 1 transversely of the wires, and extending upwardly from the frame to a level above that of the wires, and into which the wires are pressed, but said strips being yieldable to such vibration, yet preventing escape of materials between the wires and the frame, and other strips of live rubber extending parallel to the wires, and similarly disposed between the frame and the wires, to be pressed by the wires, and with the first mentioned strips defining the edges of the opening and closing the space between the wires and the frame, without unduly damping vibration of the wires.

4. In a screen for a trommel, a frame defining an opening, live rubber strips upstanding from the frame entirely about the edge of said opening, a plurality of parallel tensioned wires extending across said opening and pressing into said rubber strips, means to anchor the ends of the wires disposed on the frame outwardly of the rubber strips, to maintain the wires tensioned so that they will vibrate, the wires between the side edges of the opening being equally spaced, and the wires along each side edge being more closely spaced.

5. A trommel comprising a rotative polyhedral frame, each side of which has an opening, a plurality of parallel equally tensioned wires extending lengthwise of each side, across the opening therein, means to anchor the ends of the wires upon the frame, to maintain them tensioned, to vibrate, and a live rubber strip upstanding from 1 the frame around each opening, into which the wires press at every edge of the opening.

6. In a screen for a trommel, a frame defining an opening, live rubber strips upstanding from the edges of the opening, a plurality of parallel, equally pretensioned wires of a length to extend across said opening and over said strips, a cross bar at each end of the wires, to which all the wires are permanently secured, while pretensioned, to retain them in such relationship, and

spring means urging said cross bars apart, to tension said wires equally and to restore such wires to their pretensioned relationship, and to press them into said rubber strips.

7. In a screen for a trommel, a frame defining an opening, a plurality of parallel, equally pretensioned wires of a length to extend across said opening, a cross bar at each end of the wires, to which all the wires are permanently secured, while pretensioned, to retain them in such'relationship,

'an opening,

a shoulder at each end of said frame opening, whereon the corresponding cross bar bears, spaced members extending transversely of the frame and engaging the wires, intermediate their ends, a transversely extending plate engaging the opposite sides of the wires, intermediate the spaced members, and means to draw said plate downward into the space between said members, to tension said wires equally while the cross bars are thus engaged with said shoulders, to restore such wires to their pretensioned relationship.

8. In a screen for a trommel, a frame defining a plurality of parallel, equally pretensioned wires of a length to span said opening, a cross bar at each end of the wires, to which all the wires are permanently secured, while pretensioned, to retain them in such relationship, an upstanding shoulder at each end of said frame opening, whereon the corresponding cross bar bears, a clamping plate engaging the cross, bar and the wires secured thereto from above and clamping them down upon the frame, and spring means urging the shoulders and associated clamping plates apart, to tension said wires equally, and to restore the wires to their pretensioned relationship.

9. In a screen for a trommel, a frame defining an opening, a plurality of parallel, equally pretensioned wires of a length to extend across said opening, a cross bar at each end of the wires, to which all the wires are permanently secured, while pretensioned, to retain them in such relationship, a shoulder at each end of said frame opening, whereon the corresponding cross bar bears, means urging said shoulders apart, to tension said wires equally while the cross bars are thus engaged with said shoulders, to restore such wires to their pretensioned relationship, and a live rubber strip upstanding from the frame, inside said shoulders, and into which the wires are pressed, to prevent passage of material outwardly of said strips, without detracting appreciably from the vibration of said wires immediately at each side of and through said strip.

10. In a screen for a trommel, a frame defining an opening, a plurality of parallel wires extending across said opening, anchored at each end thereof and tensioned, whereby they tend to define a given plane, and a transverse strip of resilient material upstanding from the frame, inward of each end of the wires, of a height, when unrestrained, to extend above the level of such plane, whereby the wires are pressed into such strip,

RICHARD D. HELLER.

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