US2925911A - Vibrating screening apparatus - Google Patents

Description

Feb. 23, 1960 w. J. PARKS 2,925,911

VIBRATING SCREENING APPARATUS Filed March 26, 1954 2 Sheets-Sheet 1 5 a 56 59 i 5 Ahi INVENTOR. WALTER J. PARKS ATTODN E76 Feb. 23, 1960 w. J. PARKS VIBRATING SCREENING APPARATUS Y 2 Sheets-Sheet 2 Filed March 26, 1954 s vn m MD J R E U A W ATTQR TS VIBRATING SCREENING APPARATUS Walter J. Parks, Cleveland, Uhio, assignor to The W. S. Tyler Company, Cleveland, Ghio, a corporation of Ohio Application March 26, 1954,Serial No. 418,982

' 7 Claims. (Cl. 269-412) This invention, relating as indicated to a vibrating screening apparatus, comprises a screening apparatus having a rectangular base frame member formed of tubular sections securely fastened together in a rigid manner, having mounted thereon a plurality of pedestal supports, said pedestal support being a multiplicity of resilient support means acting in combination to support the total dead load, balance such forces as may be developed in these units, and provide vibration isolation with respect to the base frame, all of said resilient mounting means being in close proximity to one another.

-This invention further reiates to a novel design in a vibrating screening apparatus of the self-balancing type, having an actuating means for producing a vibrating or gyratory action, which action must be isolated as far as possible from the base frame member, said vibrating or gyrating action, however, producing torsions and bendi'ng moments in the framing members, which must beadequately counteracted to prevent motion of vibratory intensity in the structural parts. An apparatus ofthis general type has been described in my Patent No. 2,066,- 362.

The construction of said base frame member must further provide for easy access to the various deck or decks of the screening apparatus, and access as well to the vibrating mechanism, wheels, bearings, etc. If any of these are encumbered by the shape of the base frame member, the problem of maintenance is considerably increased.

An object of this invention is to produce an efiicient support or base frame member which is inherently rigid, ofeasy access, and less expensive construction.

A further object of this invention is to produce a Sin!- p'lified support for a vibrating screening apparatus formed of rectangular framing members, which have high mo rnents of inertia in proportion to their weight, which combine with said base frame members a plurality of pedestals upon which are mounted a housing construction provided with resilient shear type supporting units mounted inclose proximity to each other, and extending.

from the stationary supporting structure to their designated portions of the vibrating structure, including shaft supporting housings, the combination of said resilient mounting means and housing providing a simplified construction in which there is a reduced bending moment in" the base frame members and which provide easy ac cess to the screen cloth, as well as to the parts of the vibrating 'means.

1 To the accomplishment of the foregoing and related endssaid invention, then, consists. of the means hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain mechanism or structure embodying this inverttion, such disclosed mechanism or structure constituting, however, but'one. of the various mechanical forms in. which the principles of the invention may be used.

- and depth.

ECQ

In the drawing:

Fig. 1 is a side view of this invention in a vibrating screening apparatus,

Fig. 2 is a view from the discharge end of said screening apparatus along the lines 2-2 of Fig. 1,

Fig. 3 is a perspective view of the base frame member and pedestal supports, and

Fig. 4 is a view of the resilient mounting means.

This invention of a vibrating screening apparatus is particularly directed to a pedestal type base frame for said apparatus. This is an improved supporting struc ture for a vibrating screening machine, or other equivalent type of apparatus, having an actuating mechanism comprising a rotating shaft adapted to produce a gym;- tory or vibrating action in said mechanism. Said invention, then, consists of framing members comprising tubu lar construction along the lateral sides and having at the ends thereof tubular members which are secured in and through said lateral tubular members, providing a supporting point on both the internal and external surface of the lateral tubular members. .Said structure comprises the base frame.

The advantages of this structure, in and for vibrating screening apparatus, is that they have a high moment of inertia (stiffness) for a given weight to resist the bending and twisting forces which occur in said apparatus.

The particular reasons for this type of construction is that the apparatus must be designed and built in a great variety of widths and lengths. It must also be suitable for handling a wide variety of materials, some of which are very abrasive in character. It is very important, therefore, that the area immediately below the screening surface, which, of course, fits within this framing memher, be clear of members that can Wear or obstruct the necessity of providing support for actuating means nearthe center of mass of the vibrating body, is very ethciently met in this construction by the position and the elements in combination, which were, asindicated, longitudinal tubular framing members having cross tubular members which are secured as by welding through the tubular members, one of said members, of cou1'se,'be ing Onto said tubuiar members formlarger than the other; ing a base frame are a plurality of pedestals, placed symmetrically on the base frame, which serve to position the actuating vibrating mechanism.

Accordingly, this supporting structure, consisting of the base frame and pedestals, is by preference arranged.-

with reference to the base frame and the vibrating body so that the vibrating body of the mechanism is positioned above the upper edge of the base frame. two purposes. It provides that the actuating mechanism, and such eccentric weights, wheels, or other means, may havefull clearance, positioned as they normally would be centrally of the vibrating mechanism both in length bers.

adjusted without delay. This is necessary because oc- This serves It further provides room for the mechanism. to be removed and taken out, but in addition to this it insures that such additional mechanisms as are required" for the screen cloth tightening on the various decks of the vibrating mechanism are accessible for tightening Of course, the upper deck is always accessible,but where" second and third decks are required and positioned be low the center of gravity and below the vibrating mechanism, they sometimes conflict with the framing m'em- However, by this arrangement of parts thelowen ecks are accessible so that they may be tightenedand casionally new screen cloth must be installed, or the present screen cloth must be re-stretched.

This construction, then, provides for all decks ofthe vibrating mechanism to be equally accessible. As above stated, this type of construction is particularly important in multiple deck machines, generally of two,'three, or more decks, when one or more of these decks are below the actuating mechanism. In these additional decks the screen cloth is frequently difficult to adjust because the tightening bolts are in line with the framing members. By this construction of base frame and pedestals the accessibility of the lower decks is greatly improved. It can be understood that it is common practice and desirable in vibrating screens to have the actuating means in the vicinity of the center of mass of the vibrating body. This means longitudinally as well as in depth. It has also been customary in machines of this type to locate the resilient supports in pairs along the side plates of the vibrating mechanism and on the framing mechanism, said supports being preferably on a line with the axis of the shaft.

These foregoing specifications require certain definite arrangements of the shaft assembly relative to the screen body, and with prior designs without the pedestal, it was necessary to cut large portions of the top of the longitudinal supporting member away to allow the wheel or bearing housing to be removed from the shaft without raising the entire body above the base. This seriously weakened this longitudinal framing member; This invention comprises the base frame, together with a plurality of raised portions on said base frame, consisting of four symmetrically spaced pedestal mounts, two on each side on the base frame. Said pedestals are equally distant from the center of the actuating means. The top of this pedestal member serves as a platform, on which the resilient supports of the vibrating body are mounted and also where a bearing means is provided for the shaft support, in addition to the bearing means mounted on the vibrating body. It similarly provides a platform for attaching resiliently or otherwise the bearing housing of this bearing means to the base frame. By this construction the resilient supporting mounts between the base frame and the vibrating screen body, and the supporting and balancing mounts for the rotating mechanism itself, are moved closer together, and such bending moment as takes place between these two parts because of the nature of the vibrating action is reduced by their proximity to one another.

In the specification there is described the actuating,

mechanism for this vibrating screening apparatus, which consists of a revolving shaft having portions thereon eccentric with respect to each other and so balanced with respect to mass distribution that the center of revolution of the mechanism during operation is between these relatively eccentric portions. ings attached to these eccentric portions, therefore, have a gyratory motion, and when this center of revolution is midway between the eccentric portions, and the rubber units are of equal stiffness, the opposed displacement of the resilient units attached to the relatively eccentric bearing portions of the shaft, will balance each other.

The base frame structure herein disclosed is particularly eflective in supporting this mechanism inasmuch as the outside bearing housing construction is of an elongated shape and reaches out to the normal and desired location of the pedestal with side arms, and permits a closely spaced compact arrangement of the rubber, or other resilient supporting means, for both the body and the hearing housing, thus keeping to a minimum the screened sideplate area covered by parts of the mechanism. This spaced location of the pedestals, and the height of the center line of the actuating shaft, makes possible a clearance area, defined by the inside of the pedestal structure and the top of the beam, in a U shape, thus no portion All parts carried by the bear of the balance Wheel is behind any part of the structure,

In the prior designs which have hearings on the shaft outside of the screen body mounting bearings, attached resiliently or otherwise to the base frame, it has been necessary to either lift the machine clear of the base frame for disassembly of the wheels, or to cut recesses in the main structural members, thereby weakening this beam and its stifiness to a marked degree. This decrease in stiffness is very important as it increases the deflection of the beam under static and dynamic loading. For long beams this static deflection, as affecting the natural frequency of vibration, and the change in deflection under the alternating dynamic load when the resilient supporting units, for the type of mechanism described, can cause movement of the structural parts themselves which is of the nature of a vibration in amplitude and frequency. This movement is just as objectionable as any unbalance of a rotating part and must be eliminated. At times this has caused expensive engineering analyses and field work to correct. The use of a high pedestal type mount eliminates this rather unsatisfactory construction and provides in a normal way for the necessary rigidity to resist these deformations in the vibrating apparatus. This particular single pedestal means, which is used in a group to accomplish this end, carries both the resilient means for the screen body and the resilient means carrying the outside bearing housing, permitting the mounting of both these resilient units in a single housing, and again reduces to a minimum the obstructed area of sideplates, permitting easier access to the screen cloth.

Basically, then, this invention consists of a vibrating screening apparatus, which consists of a screen body shown generally at 10 floating on four large shear type resilient mountings, 11, 12, 13 and 14, and motivated by an eccentric shaft shown generally at 15. This shaft is supported by side arms 16 and 17 which also float on resilient mountings similar to those supporting the screen body, said resilient mountings being shown at 18 and 19. The displacements of the screen body 10 and its attached resilient units 11 and 12. and that of the side arms 16 and 17 and their attached resilient units 18 and 19 are in opposite directions, so that they balance each other at all times. The only contact between the screen body 10 and the base frame member 20 being through the resilient mounting means, and these being balanced against each other, there is no possibility of vibration being transmitted to the base frame member.

By this construction and arrangement of parts there is provided a drive shaft 15 and housing 21 supported by a plurality of resiliently supporting bodies, such as 18 and 19, and a portion of said shaft is offset from said screen body and a further portion of the shaft is offset out of phase with said first offset to be attached to a second resilient mounting means comprising a pair of arms 16 and 17 supported in a shear rubber mounting housing. A counterbalance fly sheet 22 is used together with the side arms assembly and this balances the screening body. Details of the vibrating structure are shown in US. Patent No. 2,066,362.

The actual operation in connection with the resilient mounting means for the side arms, and its connection with the resilient mounting means for the screen body, will be described shortly.

The base frame member comprises a tubular construction consisting of elongated members 23 and 24, of rectangular shape, formed of strong, rigid material and having side portions 25 and 26 and top and bottom portions 27 and 28. The ends of said members may be capped up as shown at 29 in the drawings. Two of said members form the lateral framing elements. Between said members are cross-framing members 30 and 31, whichabraded or wear with the rough abrasive materials which are screened in this vibrating screening apparatus. Within the confines of this framing member, and slightly above it, is the screening apparatus, supported by'means about to be described. Positioned symmetrically upon the top side at 34 to 37 of said lateral members-23 and 24 of the base framing element, are aplurality of pedestal mounts, suchas 38, said pedestal mounts comprising tubular members having a front and rear wall 39 and 40 connected by side walls 41 and 42, forming a rectangular column projecting upwardly a short distance. Across the top of each of said framing members is positioned a fiat plate forming a platform, shown at 43, and said flat plate M is connected and bent at 45 to form a side portion 46; A further bent plate 47 forms an acute angle with said first plate and is securely fastened as by bolts or rivets 98 to said first member. The ends are secured together, and a rubber shear mounting 49 comprising a mass of rubber 50 in shear formed by a central pilot 51 having a plurality of faces at an acute angle, said faces 52 and 33 being parallel to the walls 46- and 47 against which they are disposed. Projecting upwardly from said rubber shear mounting is a connection 54 to the screening body. Said resilient mounting for the screening body supports the Weight of the body so that the screening body is substantially in shear, and may move both forwardly and to the rear and up and down,

and is capable of taking a certain amount of unbalance in the screening device, caused by shifts and changes in load and other considerations.

Immediately inwardly from saidrubber shear mountings there are a total of four shear mountings, which provide for a connection inwardly, in the form of side arms 16 and 17, so that the movement between the base frame and the screening body may be compensated for by the structure earlier described in connection with the eccentrics and the gyratory motion of the driving mechanism. Said resilient mountings are directly in line with the shaft and with the center of gravity of the body, the center of gravity of the body being longitudinally centrally located as well as in depth, so that the screens are substantially in balance. By this means and by the mechanism previously described, when the screen moves in one direction the force on the internal resilient mounting means for the bearings would be in the opposite direction. Because the motion to the screening body is translated directly to its support means, by this means there is a balance of forces in said pedestal. Of course, it will be seen that under certain conditions said forces will compensate for one another, particularly when in the horizontal plane, or in the horizontal component, but in the vertical plane said forces while equal, .will be opposite, causing a bending moment. Because of the close proximity of both of said units, the relative size of said bending moments is considerably reduced over' that of earlier constructions, where the side arm mounting means and the resilient mounting means of the screening body were displaced some distance.

Thus the combination ofthe upright pedestals on the base frame member, each of said pedestals having a platform and a pair of resilient mounting means thereon, form a U. Between said U and on the center line of said resilient mounting means is the driving mechanism. Since this mechanism must be frequently maintained, this combination of structural elements permits ready access thereto without having the construction changed in other ways. This combination of units also provides access to the tightening bolts for the screen cloth on the upper deck, as well as on the lower deck, since the lower decks are positioned above the base frame elements, and the pedestal units obstruct only to avery minor extent, if at all, the efforts to tighten or remove said bolts. Thus this combination of units provides two advantages at the same time.

In addition to the above an electrical motor 55, which is frequently used as a drive means, may be mounted in some manner above the screen on the framing elements, or may be mounted to'the side, as is frequently the case. This installation is shown generally at 56. Since side mounting provides additional torsion to the base frame element, it is frequently a troublesome installation. This construction, because of its'inherent stiffness, allows the motor to be assembled in this Way without difficulty; Figs. 1 and 2 show an example of this construction. Said motor 55 drives by means of a plurality of belts 57 from its pulley 58 to the vibrating mechanism previously described. This construction provides a cantilever support 59, which projects through and is secured to a lateral framing element 23. This element is sufiiciently' rigid to withstand the torsion of'this load, and the entire framing assembly 20 is able to withstand the load.

' Although the present invention has been described in connection with a few preferred embodiments thereof, variations and modifications may be resorted to by those skilled in the art without departing from the principles of the invention. All of these variations and modifications are considered to be within the true spirit and scope of the present invention, as disclosed in the foregoing description and-defined by the appended claims.

I claim:

1. In a vibrating screening apparatus having a vibrat ing screen body withside frame members, a substantially horizontal drive shaft extending centrally through the vibrating body and having eccentrics thereon engaging. bearing members in said body for gyrating the-same as well as gyrating bearing mounting means and a side arm assembly support therefor, means for mounting resiliently the vibrating screen body, and further means for resilient mounting of the gyrating bearing members for the opposite ends of said shaft, said bearing forming with the side arm assembly support means which extend laterally in line with said resilient mounting means and connect into the inner set of mounting means, the displacement of the screen body and that of the side arm assemblies being 180 out of phase with one another, and driving means for said drive shaft, said resilient mounting means being raised on a series of pedestals, said pedestals being formed of tubular members securely fastened together to a rectangular base frame formed of tubular members.

2. In a vibrating screening apparatus, a vibratory screen body, a base frame member, means for causing a vibrating action in said vibratory body, resilient support means between said vibratory body and said base member, actuating means for said vibrating action, said base frame comprising a plurality of tubular elements having,

both lateral and cross members formedin a rectangle, said tubular elements being mounted through the ends at the junctions of the rectangle to provide a rigid support and an unobstructed area in the rectangle for the passage of material, a pair of tubular pedestal uprights on said lateral members of the base frame element, plat-forms on said pedestals, each of which has an external and an internal portion, resilient mounting means on said pedestals between said vibratory body and the external portion of said platform, vibratory mounting means on said pedestals on the internal portion between said actuating means and the platform, said resilient mounting on one side of the vibratory screen body being in a line passing through the center of the vibratory actuating means, support elements between said vibratory means and said internal resilient mounting means, said vibrating means having the support arm out of phase with the action on said vibratory body whereby the action in the screening body and the arms are opposite to one another.

3. A base frame member for a vibrating screening apparatus, particularly of the multiple deck screen type,

7 with screen cloth thereon, said base frame comprising a pair of longitudinal members formed of tubular section and a pair of cross members of-tubular section connected to said first tubular section and securely fastened onto both sides thereof, said tubular sections forming a rectangular base frame member, the center portion of which is free of obstructions for the passage of screening material therethrough, each of said longitudinal-members having a pair of tubular elements securely fastened on the upper face thereof and projecting upwardly to form pedestals, said pedestals being symmetrically mounted on the base, said pedestals having an elongated platform extending along the length ofthe longitudinal members an equidistance on each side of the pedestal, said base frame and pedestal mounts being adapted to support a vibrating screen body andactuating means therefor, together with the base frame element symmetrically positioned, platforms on said pedestals, each of which has an external and an internal portion, said platforms being in the same plane and extending parallel tothe longitudinal members and an approximate equal distance on either side of the pedestal, resilient mounting means on said pedestal between said vibratory body and theexternal portion of said platform, vibratory mounting means on said pedesteal on the internal portionbetween the actuating means and the platform in theform of a sidearm assembly, said resilient mounting means on one side of the vibratory screen body being in a line passing through the center of the vibratory actuating means, said screen body having two oirmore decks, one abovethe actuating means and one or more below the actuating means and above the lateral framing elements, access for adjustment and tightening of I said screen decks being on the external side of the screen body, vibrating means therefor, a rectangular base frame comprising a pair of longitudinal members formed from tubular section, and a pair of cross members connected to said tubular section and securely fastened on both sides thereof, ,providing a rigid, rectangular base frame having an unobstructed area therebeneath for the passage of screened material,v a pair of tubular elements forming pedestals on eacl'rof said longitudinal members symmetrically positioned, said pedestals having elongated platforms extending along the length of the longitudinal tubular members, and extending approximately an equal distance on either side of said pedestals, said platforms all being in the same plane, vibrating means connected to said platforms, and a vibrating screen body connected resiliently to the platforms and to the vibrating means, motor support means cantilevered outwardly having a base frame projectingthrough said longitudinal tubular members, said motor member having drive means connected to the actuating means of the vibrating apparatus and screen body, said longitudinal framing members being sufficiently rigid and resistant to torsion to take the load of the'ca'ntilevered motor mounting mean-s.

5. In a vibrating screening apparatus, a vibratory screen body, a base frame member, means for causing a vibrating action in said vibratory body, resilient mounting means between said vibratory body and said base frame member, actuating means for said vibrating action, said base frame comprising a plurality of tubular elements having both lateral and cross members formed in a rectangle, said tubular elements being mounted through the ends at the junction of the rectangle to provide a rigid support and an unobstructed area in the rectangle for the passage of screened material, a pair of tubular uprights or pedestals on said lateral members of body and being unimpeded by the pedestal mounts and the platforms thereon since a portion of the area along the sides of the screen body has no uprights or projections to prevent easy access therethrough, said resilient supporting means being in close proximity to one another on said pedestals and platforms, whereby the bending moment between said resilient mounting means is redueed by said proximity, said vibrating means and support arms into the internal resilient mounting means being out of phase with the action on said vibratory screen body, whereby the forces on the base frame are balanced, though causing bending moments in the rigid framing elements. v

6. The vibratory screening apparatus of claim 5, in 'which each of said resilient mounting means comprises a pair of plates positioned apart and at an'acute angle to one another, anda pilot attached to said vibratory screen body positioned between said plates and having sides which are opposed and parallel to said first mentioned plates, andapproximately equidistant therefrom, rubber mounting means in shear between said pilot and said plates, whereby the body of the apparatus is supported in rubber, which is substantially all in shear.

' 7. The vibratory screening apparatus of claim 6, in which the resilient mountingmeans and platforms are formed from a plate bent at an obtuse angle and a second plate oppositely disposed thereto at an acute angle, said plates being secured together to form an acute angle therebetween, rubber mounting means on the internal faces of said plates, a pilot therebetween'whose outer faces are parallel to said plates, said plates being on the platform and pedestals whereby the screening apparatus is supported substantially inshear.

v References Cited in the file of this patent UNITED STATES- PATENTS Great Britain May 30, 1951

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