US1597173A - Screening device - Google Patents

Description

Patented Aug. 2 1926.

umrso STATES PATENT OFFICE.

CHARLES E. BARH IG-IZT, OF CARBONDALE, PENNSYLVANIA, ASSIGNOB TO CROSS EN- GINEERING COMPANY, A CORPORATION OF PENNSYLVANIA.

SCREENING DEVICE.

Application filed August 7, 1924. Serial No. 730,584.

My invention relates particularly to that class of screening or sifting devices or machines in which material to be separated or graded is delivered upon an inclined foram inous diaphragm or table, which is mechanically vibrated to so agitate said material that the fine particles pass through the mesh of the screen while the coarse material is caused to traverse the full length of said diaphragm or screen and be discharged therefrom, and is especially directed to the mechanism by which said foraminous diaphragm is supported for agitation.

In vibrating screens it is desirable to pro vide strong vibration of'considerable amplitude at the receiving or initial end of the screen, in order to properly agitate and move the heavy load of material as received, and to quickly carry the finer particles to the bottom of the mass, so as to pass the mesh. It is also desirable to graduallyreduce the amplitude of vibration toward the discharge end of the screen so as to permit those particles of material that are just slightly smaller than the mesh to pass through. If the entire screen were subjected to the strong vibration required to treat the heavy mass of material at the receiving end, the slightly under-sized parti cles would be caused to travel the length of the screen in a series of jumps which might prevent their passing through the mesh except where they just happen to strike a perforation in such a way as to register therewith, but by reducing the vibration toward the discharge end so that these particles are just kept moving without the jumping action, they may pass through to effect the desired sizing.

Furthermore, in devices of the type contemplated wherein screens mounted upon coiled or spiral springs, or even upon springs of the leaf type transversely disposed are vibrated, considerable longitudinal movement is produced which causes the vertical vibratory movement to have such a longitudinal component as to effect a compound vibration resolving into an approximately circular or'oval movement of the it screen, which is not only less effective than a direct perpendicular movement of sald screen, but tends to be destructive both to the apparatus and to the building in which it may be housed.

The principal objects of my invention are to provide a screen so mounted that its vibratory action will be restricted to a motion perpendicular or normal to the plane of its screening surface, and when actuated the vibratory effect on said. screen will diminish gradually from its initial end to ward its discharge end.

Other objects of my invention are to provide a mounting for a screen upon which it may he so adjusted as to vary the relative amplitude of vibration ofits initial and discharge ends. a

My invention comprehends a screen adjustably mounted for vibration upon spring supports which are extended in longitudinal relation with respectto said screen, and includes means tending to relieve the weight of the screen on said spring supports.

Further objects of my invention are to embody in. a single unit a foraminous dia phragm and a subjacent imperforate pan, having means to so connect their plane effective surfaces as to vibrate in unison.

Specifically stated, the form of my inventionas hereinafter described comprises a base frame having longitudinally extended spring members supported adjacent to their ends and having an unbalanced rotary member mounted for rotation intermediate of the supports and a screen having its frame supports spaced longitudinally on said spring members and arranged for longitudinal adjustment thereon into different spaced relation to the supports of i said spring members,

My invention also includes all of the varr ous novel features of construction and arrangement as hereinafter more definitely specified.

In the accompanying drawings, Figure 1 is a side elevational view of a screening machine showing a convenient embodiment of my invention in cooperative relation with a bin for discharging material therein; Fig. 2 is a plan view of the screening structure illustrated in Fig. 1 ,as viewed in a direction normal to the plane of the screen surface,

and Fig. 3 is a transverse sectional view of the screening structure illustrated in Figs. 1 V

may be secured. together and to the stringers 1 to form the composite base frame by the bolts 7 and 8 which also respectively er;- tend through the cross ties 2 and '3.

At the region substantially equidistant from their sup-ports Q'and 3-, the spring members5 are provided with the journals or bearings 9 in which the shaft 10 carrying a pair of eccentrics or out-of-balance wheels 11 having weights 12 is mounted for rotation by having its pulley 13 connected by the belt 15 with the pulley 16 of the mo-' tor 17 which is suitably disposed adjacent to the spring support 3.

.Superposed upon the spring members 5 and connected therewith for longitudinal, adjustment is the screen frame whose standards QO-and 21 rest upon the spring members 5 and may be secured in any desired longitudinal position thereon by the bolts 22 and 23 which extend upwardly through the longit-udinally directed slots 25 and 26 in said spring members 5 and through the bores 27 and 28 in said standards, which bores intersect the transversely disposed apertures 29 and 30 according convenient shoulders 31 and 32 upon which the nuts 33 and 34 may impinge to rigidly secure said standards and spring members together in any desired longitudinal position.

The construction of the screen frame is not important in its precise details and may be widely varied. The typical illustration as shown in the drawing comprises the perforated plate or foraminous diaphragm 35 and the imperforate subjacent pan 36 arranged tocarry off the under size material which is precipitated through said foraminous diaphragm, both of which have their lateral margins clamped between the side timbers 39 and 40 of the screen frame by the bolts 11.

The side timbers 39 and 40 are conveniently connected near their ends and central region by the transversely disposed angle irons 412 and at the initial end of the screen by the cross beam l3 which also serves as' Said supporting the base frame comprising the stringers 1 upon one of the transversely dis posed brace bars serving to connect and brace the uprights or standards 51 of the bin 52 containing the material to be sifted or screened which is delivered to. the screen by the extended inclined floor'53 of said bin and controlled by the reciprocatory gate 5%.

To insure the best results in the operation of the screen it is desirable that the vibratory spring members 5 be relieved of the weight of the screen frame so as to permit the vibrating foraminous diaphragm 35 to vibrate freely under heavy load. For this purpose the springs 55 are provided, which may be connected at one end by the hooks 56 with the screen frame as shown, and at the other end with the eye-bolts 57 which are adjustably engaged with the brackets 58 suitably carried by the standards 51 of the bin 52.

The constituents of the material separated by the screen may be conveniently directed to different containers by the chute 60 which is arranged to'receive the material discharged-from the foraminous diaphragm 35 and the chute 61 onto which the material from the pan 36 is discharged.

My invention is advantageous in that by the construction contemplated the vibration is so restricted as to be directly perpendicular to the plane of the screen surface, which motion has been found to be highly desirable and far more effective and efficient than such devices as heretofore constructed where- 'in the vibration embodied a longitudinal component. Furthermore, by so adjusting the screen frame that its rear standards 21 are disposed on the spring members 5 relatively remote from the spring support 3 while the forward standardsQO are disposed relatively close to the spring support 2, a greater vibratory action is naturally effected upon the screen where the material is delivered' thereto, to wit, the initial or rearend thereof, and such vibratory action consequently diminishes gradually toward the discharge end of the screen, whereby the screen approaches a maximum efficiency.

It is to be understood that the word spring may mean any yielding member and therefore I do'not desire to limit my invention to the precise terms or details of construction and arrangement as herein set forth as it is obvious that various modifications may be made therein without deparfl ing from the essential features of my invention as defined in the appended claims.

Having thus described my invention, I claim 1. A device of the class described comprising a spring support, ascreen mounted thereon and capable of longitudinal adjustment with respect thereto, means for vibrating the support, and means for suspending the support in such inamier that when the support is vibrated th vibratory impulses throughout the support will vary in amplitude.

2. A device of the class described comprising a spring support, means for suspending the support at its ends so that when vibrated the vibratory impulses will vary throughout its length and have a maximum amplitude of vibration equidistant from said points of suspension, means for vibrating the support, a screen, and means carried by the screen and adjustable longitudinally of the support for mounting the screen at spaced points upon the support.

3. A device of the class described comprising a spring having spaced points of suspension, means arranged to vibrate said spring, arscreen and means for supporting the screen on the spring, adjustable longitudinally thereof and having spaced points of contact therewith whereby the impulses of vibration throughout the length of said screen may be varied.

4t. A device of the class described comprising a spring having spaced points of suspension, means arranged to effect the vibration of said spring, and a screen carried by said spring and restricted thereby to a vibratory motion in a direction normal to the plane ofthe screen surface and having spaced points of contact with said spring at relatively different distances from the respective points of suspension of said spring.

5. A device of the class described comprising a spring having spaced points of suspension, a vibrator carried by said spring arranged to effect vibratory impulses thereof, a screen carried by said spring and having longitudinally spaced points of contact therewith, and means whereby said screen may be adjustedlongitudinally of said spring and secured thereto with its points of contact at relatively different distances from the respective points of suspension. of said spring.

A 6. A device of the class described comprising a spring having spaced points of suspension, means arranged to effect vibration of said spring, a screen carried by said spring and having spaced points of contact therewith and adjustable thereon to vary the relative distances between said points of contact and the points of suspension whereby the impulses of vibration of said screen may be varied, and means effective to relieve the weight of said screen from said spring.

7. A device of the class described comprising a screen, a longitudinally extending resilient support therefor disposed substantially parallel thereto, having spaced points of suspension and operative to restrict the screen to a vibratory motion normal to the plane of the screen surface, means arranged to effect vibration of said support, and an auxiliary spring tending to uplift said support and thereby counter-balance the weight of the screen.

8. A device of the class described comprising a yielding support having spaced points of suspension, an out-of-balance wheel carried by the support and arranged when actuated to effect vibration of said support intermediate of its points of sus pension, whereby the region of maximum amplitude of vibration is normally equidistant from said points of suspension, and a screen carried by said yielding sup port and having spaced points of contact therewith and adjustable thereon to vary the relative distances between said points of contact and the points of suspension whereby the region of maximum amplitude of vibration of said yielding support is shifted and the impulses of vibration of the screen so varied that said impulses gradually diminish throughout the length of said screen.

9. In a screening device, the combination with a yielding support having longitudinal slots, of relatively spaced mountings for said support permitting its free vibration, means arranged to effect vibration of said support, a screen having relatively spaced standards engaged with said sup port and arranged for longitudinal adjustment along said support, and means cooperative with said standards and said slots arranged to adjustably secure the screen and support together in different longitudinal relation.

10. In a screening device, the combination with a spring having spaced points of suspension, :of means arranged to effect vibration of said spring, a screen hav ing a frame carried by said spring and having spaced points of contact therewith, a pan carried by the screen frame and extending substantially parallel with said screen in spaced relation thereto, and means independent of said frame arranged to connect said screen and pan to insure their vibration in unison.

11.-In a screening device, the colnbinal'aininous diaphragm With said transverse tion With a screen frame comprising side bars intermediate of said side bars, and bars, of means arranged to effect the vi'braspacing sleeves through Which said bolts tion of said fralne a foraininous diaextend arranged to space said foraniinous phragn havingitsinargins engaged with said diaphragm and said pan and to insureside bars, an iznperiorate pan subjacent to their vibration in unison. I

said fera-n'iinous diaphragin a plurality of In Witness Where -i, I have hel eunte set transverse bars connecting said side bars my hand this lth day of August, 1924.

and underlying said pan, bolts extended through said pan and connecting said to- CHARLES 'E. BARHIGHT.

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