US1448181A

US1448181A - Vibrating screen

Info

Publication number: US1448181A
Application number: US417768A
Authority: US
Inventors: Joseph J Babka
Original assignee: Individual
Current assignee: Individual
Priority date: 1920-10-18
Filing date: 1920-10-18
Publication date: 1923-03-13
Anticipated expiration: 1940-03-13

Description

Mar. 13, 1923. 1,448,1`81

J. J. BABKA vIBATING scREN Filed Oct. 18, 1920 Patented Mar. 13, 1952.3.

tras s rafa a' asics.

VIBRATING SCREEN.

Application filed October 18, 1920.

To aZZ 'whom 'it 'may co'ncem:

Be it known that I, JosEPH J. BABKA, a citizen of the United States of America, and a resident of Berwyn, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Vibrating Screens, of which the following is a specification.

My invention relates in general to vibrating screens, such as are used for screening or grading sand, gravel, ore, crushed rock and the like material; and the object of the invention is to provide a novel, inexpensive and highly eificient method of eausing the screen to vibrate, thereby eifecting a'saving in first cost and increased efliciency in operation.

Numerous types of vibrating screens have been designed before, and some of these prior screens have been fairly successful. S0 far as is known, however, all former screens either do not accomplish the (lesired object effec'tively, which is to produce minute high frequency vibrations; or they do so by means of excessively complicated mechanical or electrical contrivances which are not only costly to start with, but are when rotated lat high speed by some suitable' source of power, itwill vibrate at a corresponding frequency. Sincev the shaft bearings are on the frame of the screen the Vi- 0 brations are transmitted to the screen through the bearings, and the'screen will vibrate in unison with the shaft.

Having explained in general terms the object and scope of the invention the means 5 by which the desired results are accomplished will now be described more in detail, reference being had to the accompanying drawing, i-n' which Fig. 1 is a side view of my improved vibrating screen, while Fig. 2 is a top view of the same.

The screen itself may be of any'approved type. As shown herein it comprises a rectangular wooden frame about 8 ft. over all in length, and 2 ft. width, with an inner' serial' No. 417,768.

frame of square strips on which a Sheet metal or wire mesh screen is stretched and held by staples, cleats or any suitable means. The method of construction is suificiently ini dicated in the drawing, and since it is well understood by persons familiar with screens, no further consideration will be necessary on this phase of the matter.

The means for supporting the screen will now be explained. The sides 2' and 3 of the frame are attached at opposite ends to the cross pieces 4 and 5, which support the weight of the frame. The cross pieces 4 and 5 are in turn supported by means of Springs on cross pieces 6 and 7, respectively. The latter may form part of some other machine, or may be supported in any preferred manner, depending on the circumstances. As shown, two heavy sill pieces of 2x6 are set on edge and the lower cross pieces 7 fits. in a mortise about a foot from the right end. At the left the cross piece 6 is supported by two uprights, one of which lis indicated by reference Character 10, at such a height that the screen will be inclined at an ang-le of about 80 from the horizontal.

The Springs which support the cross pieces 4 and 5 are four in' number and are indicated by reference characters 11 to 14, inclusive. These Springs and associated parts are all alike. v Considering spring 14 and its mounting more in detail, the centering bolt 15 fits tightly in a hole bored in cross piece 7 and is held firmly in place by nuts above and below. A large steel disc or washer 16 is placed on the centering bolt before the upper nut is screwed down. This washer forms a bearing surface for the spring 14,

the lower coil of which fits tightly around.

the upper nut. The upper coil of the spring fits loosely around the centering bolt 15 and supports one end of the cross piece 5, there being a second washer 17 interposed between the spring and cross piece. This second washer is drilled with small holesv and is` secured to the cross piece '5 with screws.

The centering bolt 15 passes up through a central hole in the washer and cross piece,

the hole being large enough to insure 'a loose fit. The upper end of the spring may, or may not beattached to washer 17. 'If the former, the end of the spring is bent up `at right 'angles and extend' into a hole drilled in the washer to receive it. As stated before, the other three Springs and associated parts are like the one described. These Springs evidently constitute a looseor flexible support for the frame of the screen, on.

which it is free to vibrate.

The means for causing the screen to vibrate lwill next be considered. This comprises a heavy shaft 20, supported in bearings 21 and 22, which are attached to the frame of the screen. The shaft is preferably mounted some-what to the left of the center of the screen and at this point the -side pieces 2 and 3 are strengthened by ladjusted by means of the outer nuts, and if desired a heavier weight can be substituted for clip 29. The U bolt 26 is similar to the one described and may be on the same side of the shaft, as shown in the drawing, or on the' opposite side, as vwill be vexplained prese-ntly.

Power is supplied to the pu'lley wheel 30 by means of a suitable belt 31 which may be driven by the pulley wheel 32. The latter wheel is driven by any desired sourceof power, as for example, a small electric motor.

In order to hold the screen in position against the tension of the' belt, two loose or flexible connections are provided at` the upper end offthe screen. These consist lof two i. shaped bars of iron 34 and 35 which are bolted to the cross piece' 6, and two similiar 11. shaped bars 36 land 37 which are bolted to the' cross piece 4, together with the bolts 38 'and 39 by means of which the corresp/onding bars are connected. 'It isv noted that the holes` through which bolts 38 and 39 pass are large enough to make a loose ifit, so 'that the attachments will not interfere with the vibrations of the screen.

The materialmay be vfed to the screen in any desired manner, many ways being well known. Undercertain circumstances some type of beltconveyor may be used. I have shown, however, a hopper indicated by reference character 40, which is suitably supported so that the opening at the bottom is about two inches above the surface of the screen. The hopper is preferably provided with a vertically movable gate at 41 in order I that the width of the opening may be adjusted. 'f

Hav'i'ng explained the construction of my improved screen, I will now describe its operation briefiy. Assume that the hopper i 40 is filled with gravel or crushed rock, or any other material that is' to be run through the screen. lVhen the material, gravel for instance, is dumped into |the hopper it/will run through' the opening at the bottom of the hopper and form a hill or ridge extending across the screen the full width of the hopper. Some of the' finei' particles of course fall through the screen but the openings are soon plugged by larger pieces of material and a stable condition is reached almost at once. The power is now switched on. As the shaft speeds up it begins to vibrate, and at full speed, about` 1800 R. P. M., a. steady high frequency vibration is secured. The motion of the shaft is communicated to the screen and as a matter of fact the shaft and screen vibrate in unison and as a single unit. The'vibrations have an immediate effect on the material which has flowed through the hopper. The fine particles pass through the screen in a steady stream, while the larger pieces descend on the surface of the screen and pass' over the end. Fresh material ,of course runs down from the hopper as fast as that below is displaced.

It is not to be understood that the screen is shaken violently up and down during these Operations. On the contrary, the up and down motion is slight, being scarccly perceptible to the eye, and is accompanied y`by ahumming sound of a pitch corresponding to the frequency of the vibrations. As

stated, the amplitude of the vibrations is extremely small, and is largely independent of the size of the weights, which are much too light to cause forced vibrations of the screen. As a matter of fact the screen is operative if the weights are entirely omitted, since any heavy shaft has a'tendency to vibrate' when rotated at high speed. The combination of the spring supported screen and the heavyv shaft, however, have a certain natural period of vibration and the weights are useful in adjusting this period to the frequency of the power source. this purpose they may be set on the shaft at different angles to each other, or the out- For side clips may be moved relative to the shaft.

' It will be seen that I have devised novel and effective means for vibrating a. screen of the type described, comprising an unbalanced shaft mounted on the frame of the screen, whereby the vibrations of the shaft may be transmitted direct to the screen without intervening mechanism. VVhile have shown and described a certain specific embodiment 'of my invention, it is possible to apply the principles involved to many types of screens and similar devices, and fin different ways; andl do not therefo-re wish to be held strictly to the precise form gles to the plane of said belt.

of my invention which is shown herein, but desire rather to secure and have protected by Letters Patent all modifications of my invention which come fairly within the scope of the app'ended claims. IVhat I claim is:

l. In a vibrating screen, a frame supported on Springs, a' vibrating device comprising a shart supported on said frame, a belt for driving Said shaft, and holding means at one end of said screen independent of the supporting springs for takmg the pull of the said belt, the said belt and holding means constitut-ing means for limiting the` vibrations of said Screen to a plane at right an- 2. In a vibrating screen, a frame supported on Springs, a vibrating device comprising a Shaft supported on said frame, a belt for driving said shaft, and a pair of holding devices at one end of Said screen for holding the same in position against the pull of the said belt, the said belt and holding'devices constituting means for preventing said screen from vibrating horizontally while permitting the same to vibrate freely up ,and down.

3. In a vibrating screen, a frame, a vibrating device comprising a shaft supported on said frame, a belt for driving the said sha-ft, a plurality of compression coil Springs beneath the said frame to support the weight thereof, the Said frame resting loosely on said Springs, and retaining means for holding the screen in position against the 'pull'o-f the said belt.

4. In a vibrating screen. a frame, a vibrating device comprising a shaft supported on said frame, a belt for driving the said shaft, a plurality of compression coil Springs beneath the said frame to support the weight thereof, the said frame resting loosely on said Springs, independent means for holding the :screen against the pull of said belt, and

loose fitting positioning means associated with each spring for retaining said screen in approximate position.

5. In a vibrating screen, a frame, Springs at opposite ends of said frame supporting it at an angle from the horizontal, an unbalthe screen while at the lower end the vibrations are unrestricted.

6. In a vibrating screen, a frame, a vibrating device comprising a shaft supported on said frame, a substantially horizontal belt for driving said shaft, retaining means at one endl of said screen for holding the same in position against the 'pull of the belt, the

.arranged to permit said frame to vibrate freely up anddown.

7. In a vibrating Screen, a frame, a' vibrating device comprising an unbalanced shaft supported on said frame, a driving belt and suitable holding devices pulling in opposite directions on said frame, whereby longitudinal movement of the frame is substantially prevented, and a plurality of compression ccil Springs upon which the said frame is loosely supported, whereby it is adapted to vibrate freely up 'and down.

8. In a vibrating Screen, an inclined frame, a vibrating device comprising .a transverse rotatable shaft supported in bearings on said frame, weights on said shaft to unbalance the same in order to Set up vibrations in the screen When the shaft is rotated, and means for retaining said screen in position arranged to permit the same to vibrate freely up and down whileopposing vibrations in the plane of the screen, said means including Springs of the compression type offering a resilient action only to vibrations in a plane perpendicular to' the plane of the Screen.

9. In a vibrating screen, an inclined frame,

a vibrating device comprising a transverse rotatableshaft supported in bearings on said frame, weights on said shaft-to unbalance the same in order to cause the screen to Vibrate when the shaft is rotated, means for suppressing vibrations inthe plane of the screen, and means for supporting the weight of the screen comprising compression Springs acting in a plane perpendicular to the plane vof the screen, thereby permitting the screen to vibrate freely up and down.

'Signed at Chicago, county of Cooka and State of Illinois, this ninth day of October, 1920.

JOSE-PH J.