US2804967A

US2804967A - Vibrating screen

Info

Publication number: US2804967A
Application number: US412205A
Authority: US
Inventors: Jr Andrew Hyslop
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-02-24
Filing date: 1954-02-24
Publication date: 1957-09-03
Anticipated expiration: 1974-09-03

Description

Sept. 3, 1957 A. HYsLoP, JR

VIBRATING SCREEN 2 Sheets-SheeI l Filed Feb. 24, 1954 FIG. 2

oooooooo JMU INYENTOR ANDREW ,NIW

Sept 3, 1957 A. HYsLoP, JR 2,804,967

4 VIBRATING SCREEN A Filed Feb. 24. 1954 2 snee t 2 FIG. 4 ,6

-F|G5 mvENTon ANDREW HYsLoP,'JR.

` ATTORNEY.

VIBRATING SCREEN Andrew Hyslop, Ir., Mount Pleasant, Ohio Application February 24, 1954, Serial No. 412,265

6 Claims. (Cl. 198-220) This invention relates to vibrating screens, conveyors, and the like, and, more particularly, to the vibratory driving mechanism therefor.

Specifically, the vibratory driving mechanisms of this invention belong to that class in which counter-rotating weights are employed. The forces exerted by the weights combine to produce a resultant force that is used to drive a screen or the Ilike in approximately rectilinear motion. The drive mechanisms of this class that are disclosed in the prior art as well as those in present use have disadvantages that severely restrict their commercial acceptance and application.

in many of the present units of the above-mentioned lclass of vibratory mechanisms, the forces producing motion are exerted in different planes. Consequently, there results a twisting force on the unit which serves no useful purpose. The twisting force may be counteracted by suitable bearing and housing design, but at some additional expense. The twisting force may also be eliminated by using weights composed of several units to introduce compensating forces. However, in such cases, the supporting shafts must be made large to transmit the large forces to widely separated support bearings. Since drive units of this type are more effective if the structure weight is kept to a minimum, it is highly desirable to eliminate any weight not necessary to achieving the useful objective of the mechanism.

Devices of the aforementioned class generally produce their usable force at approximately the center of the driving mechanism. ln screens or conveyors, the members transmitting this force to the screen or pans are usually the side frames of the screens or conveyors. Therefore, a relatively heavy beam member is necessary to transmit the motion producing force from the center of the drive unit to the screen side members. Such a beam adds greatly to the objectional dead weight. In fact, with this type of drive, the screens or conveyors are usually limited to a maximum width of six feet due to the very heavy beam construction necessary for a wider span. However, it is often desirable to use screens or conveyors wider than this in order to avoid the necessity for a multiplicity of smaller units.

' In accordance with the present invention, a vibratory driving mechanism is provided wherein the internal arrangement of parts permits the elimination of the above cited disadvantages. rl`he mechanism comprises two counter-rotating Weights which rotate in the same plane on supporting shafts. The Vlatter are so arranged with respect to each other and to the gear and drive assemblies that their axes of rotation may be placed in direct or as close alignment as 'desired with the side frames of the screen. Little structure is required to transmit the useful motion producing force to the side frames. Accordingly, the counterbalancing forces are easily taken care of through a light frame construction. The forces produced by the rotating weights occur in the same plane with no twisting force being produced. This arrangement provides for a minimum bearing spacing, thus nite States Patent O f Y ice allowing relatively light construction. Because of the resulting light construction, it becomes possible to make the screens considerably wider than heretofore and also to increase the motion producing force with a consequent improvement of the screening action. High screening forces with higher frequency of vibration are particularly desirable in the screening of material in ne sizes to prevent blinding and to improve screening efficiency. Even with these extremely high screening forces, no additional angular bracing is required in the supporting structure because of the inherently balanced construction of the mechanism. This effects important reductions in installation costs and is especially advantageous in screening additions to existing structures where it is often extremely diflicult to absorb the reactive forces of many high speed screening devices.

For a better understanding of my invention, its objects and advantages, reference should be had to the following description and to the drawings in which:

Figure l is a side view in elevation of a vibrating screen assembly embodying my invention;

Figure 2 is an end view in elevation of the assembly of Figure l, showing the relative arrangement of screen and vibrating mechanism;

Figure 3 is a View in elevation of the driving mechanism along line 3 3 of Figure 2;

Figure 4 is a View in elevation of the driving mechanism along line 4 4 of Figure 1; and

Figure 5 is a cross-sectional View of the driving mechanism along line 5 5 of Figure 4.

Referring to the drawings and particularly to Figure l, numeral 10 designates a combination conveyor and screen freely suspended in an inclined position from a pair of beams 12 by means of ropes 14. The latter are secured at their lower ends to side frames 16 of the screen assembly. An improved vibrating drive mechanism i8 is rigidly attached to and `carried by the upper portion of the screen frame. Suspended from a transverse l-beam 20 which is secured to the beams 12 is an electric motor 22 having a pulley and belt assembly 24 for driving the mechanism 18.

A portion of a Isolids feed chute 26 is shown merely to indicate the point where solids such as coal, sand, and the like may be added. A deck consisting, for purposes of illustration, of a screen 2S (see Figure 4) is supported from the side frames 16 above an imperforate bottom wall 3b of the `screen assembly. The smal-ler material passing through the screen plate 28 on to the bottom wall 39 is discharged through an outlet chute 32 (Figure l) for further treatment or recovery; while the larger portion remaining on the top of the screen plate is discharged through an outlet chute 34, also for further treatment or recovery.

The improved vibratory driving mechanism 18 which is adapted to vibrate the screen assembly 10 will now be described. The mechanism is arranged in a metal housing 4t) that is divided into two box-

like compartments

42 and 44 by a Wall 45. Compartment 42 contains a horizontal main drive shaft 46 positioned lengthwise of the compartment and transversely with respect to the side frames 1d of the screen assembly. The shaft is supported for rotation within the compartment by two

bearings

48 and 50 that are carried respectively by the legs of an inverted U-shaped member 52. The latter is suitably secured to the dividing wall 45. One end of the main shaft 46 extends laterally through a side wall of the compartment 42 in rotating and laterally locking engagement with a bearing assembly 54. A wheel S6 is provided at this end of the shaft outside the compartment to serve as part of the pulley assembly 24.

Compartment 44 contains two weights 6i) and 62 eccentrically supported for synchronized rotation in the same plane by two

parallel shafts

64 and 66 respectively. The two shafts are rotatably supported within the compartment by

suitable bearing assemblies

68 and 70, respectively, in the top wall of the compartment'andtby bearing assemblies '72 andl 74, respectively', in the dividing wall a5. The two

shafts

64 and 66 are arranged at right angles to the main drive shaft 46, with their axes of rotation in substantial alignment, respectively, with the two side frames 16 of the screen assembly. The

weights

60 and 62 are identically positioned on their respective shafts so that they rotate in the same plane.

The main drive shaft 46 is operatively connected to the two

weight supporting shafts

64 and 66 by means of two right angle gear assemblies located in compartment 42. The gear assembly connecting shaft 64 with mainv shaft 46 comprises a gear 76 carried by the main drive shaft and a constantly meshing gear 78 carried by the shaft 64 at right angles to gear 76. vThe gear assembly connecting shaft 66 with main shaft 46 comprises a gear St) carried by the main drive and a constantly meshing gear S2 carried by the shaft 66 at right angles to gear titl.

Gears

76 and 80 on the drive shaft 46 are identical and are arranged to engage their respective gears which also are identical onV the supporting shafts at such positions that the two supporting

shafts

64 and 66 rotate in opposite directions but at identical velocities.

v The operation of the above described screen assembly and vibratory drive mechanism is as follows. Upon encrgization of the electric motor 2, the main drive shaft 46 is rotated by means of the pulley assembly 24. Rotation of the drive shaft 46 produces rotation of the

supportingshafts

64 and 66 at the same velocity but in opposite direction. The

eccentric Weights

60 and 62 rotate in synchronism. Since they rotate in opposite directions their centrifugal forces balance and neutralize each other in such a Way that no resultant force is created at right angles to the screen frame 10. However, resultant forces are generated parallel to the screen frame it) and in alternating direction at the same frequency as the rate of rotation of the

weights

60 and 62, and with a maximum total combined force equal to the sum of the centrifugal forces of the weights.

Thus Vi t will be clear that the assembly is uniquely selfbalancing with no twisting force being produced. Little structure is required to transmit the useful -motion producing force to the side member. The counter-balancing forces are easily taken care of through light construction. Furthermore, because of the arrangement of the main drive shaft with respect to the two eccentric weight supporting shafts, the screen may be made any width by simply altering the length of the shaft and yet keeping the weight supporting shafts relatively close to the screen side frames, irrespective of frame width.

lt should be noted that the assembly is so constructed and arranged that the vibratory forces, i. e. the resultant forces, are transmitted directly to the side frame members 16. With this type of arrangement the need of heavy cross members is eliminated.

In prior practice, the vibratory forces would be transmitted from the vibrator mechanism to the cross members. Then the cross members in turn would transmit the vibratory forces to the side frame members. An inherent disadvantage of the cross members transmitting the vibratory forces to the side frame members is the torque or bending moment created in the cross members by the vibratory forces. When the resultant vibratory forces are not aligned with the side frame members, bending moment or torque will be exerted on the cross members equal to the product of the resultant vibratory force and the moment arm. The moment arm can be dened as the distance between the resultant vibratory forces exerted by the vibrator mechanism and the side frame members. This is so because the side frame members receive and transmit the vibratory forces to the screen. I t has heretofore been neessary to. compensate:

vassioma? for this torque or bending moment by including cross members of heavy construction which, as stated is unesirable because of the additional weight and screen width limitations.

In the present invention, since the resultant forces are aligned with the side frame members, the torque or bending moment on the cross members is eliminated. Thus,

, the cross members are notv required to function as force transmitting means and hence can be of lighter construction which increases the efficiency and adaptability of the vibrating screen.

According to the provisions of the patent statutes, I have explained the principle, preferred construction, and mode of operation of my invention, and have illustrated and described what I now consider to represent its best embodiment. However, l desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

l. Vibratory apparatus comprising a frame to be vibrated, said frame having two sidc members supporting a deck therebetween, a vibratory mechanism carried by and rigidly attached to said frame and arranged to vibrate said frame, said mechanism including a pair of similar eccentric weights mounted for rotation in the same plane on a pair of rotatable shafts whose axes of rotation are in substantial alignment, respectively, with the side members of said frame, a main drive shaft arranged at right angles to said rotatable shafts and transversely with respect to said frame, and similar right angle gear assemblies operatively associated with said main drive shaft and said rotatable shafts for providing rotation of the latter in synchronized opposite directions to thereby effect vibration of said frame, and means for effecting rotation of said drive shaft.

2. Vibratory apparatus comprising a frame to be vibrated, said frame having two side members supporting a deck in an inclined position therebetween, a vibratory mechanism carriedV by and rigidly attached to said frame below the higher end of said deck and arranged to vibrate said frame, said mechanism including a pair of similar eccentric weights mounted for rotation in the same plane en a pair of rotatable shafts whose axes of rotation are in substantial alignment, respectively, with the side members of said frame, a main drive shaft arranged at right angles to said rotatable shafts and transversely with respect to said frame, and similar right angle gear assemblies operatively associated with said main drive shaft and said rotatable shafts for providing rotation of the latter in synchronized opposite directions to thereby effect vibrations of said frame, and means for effecting rotation of said drive shaft.

3. Vibratory apparatus comprising a frame to be vibrated, said frame having two side members supporting a deck therebetween, a vibratory mechanism carried by and rigidly attached to said frame and arranged to vibrate said frame, said mechanism including a pair of similar eccentric weights mounted for rotation in the same plane on a pair of rotatable shafts whose axes of rotation are in substantial alignment, respectively, with the side members of said frame, a main drive shaft arranged at right angles to said rotatable shafts and transversely with respect to said frame, and means operatively associated with said main drive shaft and said rotatable shafts for providing rotation of the latter in synchronized opposite directions to thereby effect vibration of said frame, and means for effecting rotation of said drive shaft.

4. Vibratory apparatus comprising, in combination, a frame movably suspended from a rigid supporting structure, said frame having two parallel side members supporting a deck in an inclined position therebetween, a vibratory mechanism carried by and rigidly attached to said frame below the higher end of said deck, said mechanism includinga pairof similar eccentric weights mounted for rotation in the same plane on a pair of rotatable shafts whose axes of rotation are in alignment, respectively, with said side members of said frame and whose plane of rotation intersects said deck at approximately the center thereof, a main drive shaft arranged at right angles to said rotatable shafts and transversely with respect to said frame, and similar right angle gear assemblies operatively associated with said main drive shaft and said rotatable shafts for providing rotation of the latter in synchronized opposite directions to thereby effect vibration of said frame, power means secured to said rigid supporting structure and movable means operatively interconnecting said power means and said drive shaft for effecting rotation of said drive shaft.

5. Vibratory apparatus comprising a frame member having a pair of side members, vibratory mechanism secured to said frame member and operable to impart mo tion thereto, said vibratory mechanism comprising a pair of supporting shafts, eccentric weights carried by each of said supporting shafts and operable to rotate in the same plane, each of said supporting shafts having its axis of rotation substantially aligned with said respective side member so that upon rotation the vibratory forces exerted by said eccentric weights will be transmitted directly to said side members, and means to rotate said supporting shafts in synchronized opposite directions.

6. A vibratory apparatus comprising in combination a frame movably suspended from a rigid supporting Cil structure, said frame having two parallel side members supporting a deck in an inclined position therebetween, a vibratory mechanism carried by and rigidly attached to said frame, said mechanism including a pair of similar eccentric weights mounted for rotation in the sameplane on a pair of rotatable shafts whose axes of rotation are in substantial alignment, respectively, with said side meinbers of said frame and whose plane of rotation intersects said deck at approximately the center thereof, a main drive shaft arranged at right angles to said rotatable shafts and transversely with respect to said frame, and similar right angle gear assemblies operatively associated with said main drive shaft and said rotatable shafts for providing rotation of the latter in synchronized opposite directions to thereby effect vibration of said frame, power means secured to said rigid supporting structure, and movable means operatively interconnecting said power means and said drive shaft for effecting rotation of said drive shaft.

References Cited in the tile of this patent UNITED STATES PATENTS 1,668,984 Simpson May 8, 1928 FOREIGN PATENTS 887,444 Germany Aug. 24, 1953