US1931657A

US1931657A - Vibrating screen

Info

Publication number: US1931657A
Application number: US551073A
Authority: US
Inventors: Theodore B Hetzel
Original assignee: Link Belt Co
Current assignee: Link Belt Co
Priority date: 1931-07-16
Filing date: 1931-07-16
Publication date: 1933-10-24
Anticipated expiration: 1950-10-24

Description

' ci 24, 1933. T, B. HETZEL 1,931,657

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BY his ATTORNEY@ Patented Oct. 24, 1933 UNITED STATES VIBRATING SCREEN Theodore B. Hetzel, West Chester, Pa., assignor to Link-Belt Company, Chicago, Ill., a corporation of Illinois Application July 16, 1931. Serial No. 551,073

7 Claims.

This invention relates to improvements in vibrating screen structures.

One of the objects of this invention involves a novel combination of supporting screen box, eccentric drive for the screen box, and long leaf springs interconnecting the screen box and the support.

A further object of this invention is the pro- Vision of an association of these velements for` the purpose of securing a screen action which is uniform, ste. dy, and of considerable intensity. A further object of this invention involves the interconnection of the screen box and supportby means of leaved springs terminating in spiral spring connections for modifying the normally circular movement of the screen surface into a more or less elliptical movement.

These and other objects, as will appear from the following disclosure, are secured by means of this invention.

This invention resides substantially in the combination, construction, arrangement, and relative location of parts, all as will be described in greater detail below.

Referring to the drawings- Figure` 1 is a side elevational View of the screen of this invention;

Fig. 2 is an enlarged detail cross-sectional view, taken on the line 2--2 of Fig. l;

Fig. 3 is a vertical central cross-sectional view through one of the bearing supports and one of the driving eccentrics; and

Fig. 4 is a side elevational view of a modified form of screen employing this invention.

'Ihe structure of this invention comprises a supporting frame 1 of anysuitable form and shape made preferably of steel channel beams cross braced in any suitable manner. Mounted on the sides of this frame arebearing supports 2 40 in which a shaft 3 is journaled. The shaft is provided at one end 'with a driving pulley 4, or

other suitable driving connection. Mounted on this shaft by means of the bearing housing shown generally at 6 is the screen box 5. This screen 45 box has not been shown in detail since it may be of many known forms of construction and,

of course, includes in the bottom thereof a suitable screen cloth or wire secured vin. place by any one of a number of well known tensioning devices. Mounted on the shaft are two unbalancedpulleys shown at 7. Depending from the under surface of the screen box near each end thereof, and on each side thereof, are the brackets 8 provided with pintles 9. A long compound leaf spring 10 is secured near the center to a supporting bracket 12 which is provided with an arcuate slot 13. Secured to 'the cross braces 17 is an anchoring plate 16 mounted so as to be adjacent the bracket 12. A suitable fastening nut and bolt 14 pass through the plate 16 and the slot 13 of the plate l2 so that the bracket 12 may be secured in any one of a number of different positions with respect to the fixed plate 16. An opening 15 in the side frame of the support permits of access'to the nut and bolt 14. The ends of the upper leaf of the compound spring 10 terminate in spiral springs 11 which are secured at their centers to the pintles 9. As is clear from Fig. 1, and the construction described above, the screen box may be adjusted to any one lof a number of inclined positions with respect to the horizontalv between predetermined limits.

Fig. 2 shows the relationship of the supporting frame, cross braces, bracket 12, plate 16, and the fastening nut and bolt 14.

The details of construction are shown in Fig. 3. The shaft 3, of course, extends between the sides of the'fsupporting frame 1 andA is provided with eccentric portions 20 of reduced diameter. As shown in Fig. 3 the center line of the concentric portion of the shaft is shown at A. vThe center line of the eccentric portion 20 is shown at B., .'I'he eccentricity therefor is represented by the distance between the lines A and B. The shaft 3 is provided with a second reduced concentric portion 19 which jourf naled in the bearing 2. This portion is provided with a bearing sleeve 21 upon which isv mounted an inner roller race 22. Surrounding this inner roller race is an outer roller race 23 which is mounted in the bearing 2 between the parts 24 and '26 thereof, which forms an enclosed casing. Thisenclosed casing is mounted on a suitable support 25 by means of which it may be attached to the side frames l. The reduced portion 18 of shaft 3 extends through this casing and is provided with a pulley or other suitable driving connection 4. The unbalancedflywheel 7 is shownprovided with a weight 28 which may be circumferentially adjusted and then locked in place. The eccentric casing, shown generally at 6, comprises a shell 29 closed by means of a cover plate 30 and within which is mounted an outer roller race 32. Mounted within the outer roller race is an inner roller race 31 which surrounds the eccentric portion 20 of the shaft 3. Extending between the eccentric housings 6 is a cylindrical casing 33 which entirely encloses the shaft 3 so that it is protected from the intrusion of dirt, sand, and other foreign materials. It is, of course, apparent that the portions 18, 19 and the central concentric portion of the shaft 3 are all on the same central axis and that the eccentric portion 20 is cylindrical and formed about the axis B which is displaced a slight distance from the main axis A. Thus, as the shaft revolves, the screen frame and eccentric housings would travel in a small circular path determined by the eccentricity of the eccentric portion 20.

This circular movement of the screen frame and the cloth mounted therein is modified into an elliptical movement by reason1of the long compound leaf springs 10 which interconnect the screen frame with the supporting base. This modiiication of the normal action of the screen driven by an eccentric is further attained by reason of the fact that the transverse supporting shaft 3 is mounted ouside of and spaced from the center of gravity of the screen box. It will, of course, be apparent that although this shaft is shown mounted below the center of gravity, the structure may be modified within the scope of this invention so that it is mounted above the center of gravity. It is hardly necessary to point out that the weighted pulley is mounted in relation to the eccentric so that they counterbalance each other insuring smoother operation.

Byfmounting the shaft 3 away from the center of gravity. of the screen box the eccentric drive shaft effects greater unbalanced kinetic forces to provide a uniform, intense screening action. 'I'he inter-position of the leaf springs in the manner shown causes the particles on the screen cloth to describe qelliptical paths of such size and direction that the action on the material passing over the screen is most eective. Experience with a screen of this nature has demonstrated that at the receiving end of the screen the tendency is for a retardation and quick screening of the material thereon, while at the discharge end the motion assists the oversized particles to leave the screening surface rapidly. l

A modified form of structure is shown in Fig. 4 employing the principles of this invention. At 40 are the supporting standards which are provided at their top with arcuate surfaces upon which complementary supporting members il are mounted and secured thereto in any one of a number of different angular positions by f`stening means 42. -The bearing housings 47 are mounted on the supports 41 and have journaled in them a transverse shaft 48 which is connected to the screen box 44 by means of eccentrics and eccentric housings, as previously described. The shaft 48 is provided with a' suitable driving member 49. As before, an unbalanced pulley 50 is mounted on the shaft 48. 'I'he long compound leaf springs-43 are secured to the support 41 near their center and terminate as before in spiral springs 46 which are attached to the ends of the screen box by means o f brackets 45.

It should be noted here that if desired the spiral springs 46 instead of extending upwardly could just as well extend downwardly without departing from this invention. The operation of this form of screen structure is substantially the same as that described in connection with Figs. 1 to 3 inclusive.

From the above description it will be apparent that this invention resides in certain principles of construction and operation which may be set forth in other physical forms and I do not, therefore, desire to be Strictly limited to the disclosure as given for purposes of illustration but rather to the scope of the appended claims.

What I seek to secure by United States Letters Patent is:

l. A vibrating screen of theV type described .comprising a supporting frame, a screen box, a

shaft journaled on the frame, eccentric driving connections between the screen box and the shaft, compound leaf springs terminating in involutely curved springs, means for securing the leaf springs near their center to the supporting frame, and means for attaching the involutely coiled ends of the leaf springs to the screen box.

2. A vibrating screen of the ntype described comprising a supporting base, a screen box, a shaft journaled on the base, eccentric driving connections between the shaft and the screen box, long leaf springs secured to the supporting base, said leaf springs terminating at their ends in coiled springs, and means for connecting the centers of the coiled springs with the screen box.

3. A vibrating screen of the type described comprising a supporting base, a screen box, a shaft journaled on the base, eccentric driving connections between the shaft and the screen box, long leaf springs secured to the supporting base, said leaf springs terminating at their ends in coiled springs,means for connecting the centers of the coiled springs with the screen box, and counter balancing means mounted on said shaft.

4. A vibrating screen of the type described comprising a supporting base, a shaft journaled on said base, a screen box 'supported on said 'shaft by eccentric driving means, a compound leaf spring terminating at each end in coiled springs, means for securing the coiled springs at their inner ends to the screen box, and adjustable means for securing the leaf springs near ltheir center to the supporting base, whereby the lscreen box may be inclined at different angles to the horizontal.

5. -A vibrating screen of the type described comprising a supporting frame, a screen box, eccentric driving means for supporting the screen box on the frame and for vibrating it, long leaf springs -terminating in involute spring coils secured to the supporting frame, and means for attaching the coiled ends of the springs to the screen box.

6. A vibrating screen of the type described comprising a supporting frame, a transverse shaft journaled on said frame and having spaced eccentrics formed thereon, a screen box, means for attaching the screenbox to the transverse shaft at the eccentrics, long compound leaf springs terminating in spirally coiled ends, means for attaching the leaf springs to the supporting frame, anunbalanced Weighted pulley secured to said shaft and pintled brackets interconnecting the screen box and the centers of the coiled ends of the leaf springs.

7. A vibrating screen of the type described, comprising a supporting frame, a screen box, a shaft journaled on the frame, eccentric driving connections between the screen box and the shaft, longitudinal members terminating in coiled springs at each end, means for anchoring said members at their centers, means for attaching the coiled spring to the screen box and said screen box longitudinal members, means for anchoring said members at their centers being angularly adjusted about said shaft and means for securing them in various angular positions.

THEODORE B. HETZEL.