US2208596A - Reciprocating screen - Google Patents

Description

July 23, 1940. w. J. PARKS 2,208,596

RECIPROCATING SCREEN Filed Sept. l. 1937 2 Sheets-Sheet l l?) INVENTOR. @5g 5 CJaZZe/ f SPa/'s ATTORNEY5 July 23, 1940. w, J, PARKS 2,208,596

RECIPROCATING SCREEN Filed Sept. l, 1957 2 Sheets-Sheet 2 ATTORNEY Patented July 23, 1940 UNITED STATES PATENT oFFicE- 2,208,596 BECIPBOCATING SQREEN Walter J. Parks, Shaker Heights, Ohio Application September l, 1937, Serial No. 161,987

8 Claims. ((1209-365) The present invention relates to a reciprocating screen construction and has for its particular object the elimination of vibration from the supporting structure of the mechanism. My invention relates to a multiple screen frame type of construction wherein two or more screen frames are mounted upon a common base and reciprocated by the operation of a common actuating mechanism. The construction embodying the principle of my invention is particularly adapted for flat angle operation or reciprocating screens disposed in a horizontal plane.

To the accomplishment of the foregoing and related ends, said invention, then, 'consists of the means hereinafter fullydescribed and particularly pointed out in the claims.

The annexed drawing and the following description set forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of. various mechanical forms in which the principle of the'invention may be used.

In said annexed drawings:

Fig. 1 is a side elevational view of an apparatus embodying the principle of my invention;

Fig. 2 is an end elevation of the apparatus shown in Fig. 1;

Fig. 3 is an enlarged, detailed sectional view taken substantially along line 3-3 of Fig. 1;

Fig. 4 is an enlarged, detailed sectional view taken substantially along line 4-4 of Fig. 3, and in the direction of the arrows;

Fig. 5 is an enlarged, detailed sectional view taken substantially along line 5-5 of Fig. 1;

Fig. 6 is a top plan View of the apparatus showing a modified form of construction;

Fig. 7 is a side elevational view of the apparatus shown in Fig. 6, and

Fig. 8 is an enlarged, detailed sectional view taken substantially along the line 8-9 of Fig. 6.

Now referring more particularly to the drawings, there is shown therein a supporting structure or base I above and below which are mounted thescreen frames 2 and 3 by means of the resilientrubber mounting blocks 4 and 5 respectively. As will be seen from Fig. 5, therubber blocks 5 are cured, vulcanized, or otherwise attached to themetal plates 1 and 8. 'I'he metal 'plate 1 is bolted to theflange 9 on the cross shaft I0, and themetal plate 8 is bolted to the vehicle bracket Il on the base I.

A drive shaft I2 is mounted in the bearings I3 on the base I and carries the drive pulley Il on its outer end. A hollow cylindrical member or tube I5 is journalled by means of the bearmaximum velocity. Similarly, the accelerations ing I6 on the eccentric portion Il of the drive `shaft I2. Connecting rods I8 and I9 lead-from the tube I5 to thescreen frames 2 and 3 respectively. The connecting,V rods as shown in the accompanying drawings are in the form of laminated or leaf springs so that they will be longitudinally rigid but capable of lateral deection. Equivalent connecting means` such as solid connecting rods pivotally connected at each end can equally well lbe employed in place of the leaf spring rods I8 and I9. y

Thescreen frames 2 and'3 can carry one or more screen decks, but due to the fact that theV relative motions are such that the materialto be screened travels in opposite directions on the screen frames, it is preferable that a solid plate 2l be mounted on the bottom of thetop screen 2 in order to convey Screen material down through thedelivery chute 22 to the right hand or feed end of thelower screen frame 3. 20

It will be noted that the connecting rods I8 and I9 are disposedat 90 to each other, and at 54? to the horizontal. This means that the direction of travel of each of thescreen frames 2 and 3 will be at 45 to the horizontal, but one of the frames will be moving forwardly and upwardly while the other is moving forwardly and upwardly in the opposite direction, and the resultant motion of each of the screens is a complementary simple harmonic motion at right angles to each other. Thus when one of the screen frames or reciprocating bodies is at the end of its stroke and has a zero velocity, the other screen frame will be at the center of its stroke with a 5 and consequently the reciprocating forces exerted upon and by each of the screen frames will be so related that the vector sum of these forces, transmitted through the connecting rods I8 and I9 will always have an instantaneous constant value directed away from the center of the drive shaft I2 and revolving in synchronism with it, and accordingly they can be balanced bymeans of a set of rotating eccentric weights orbalance wheels 20 mounted upon the shaft I2, thus eliminating the transmission of any reciprocating forces or vibration to the base I.

It will be noted that the total Weight or mass of thescreen frames 2 and 3 are substantially equal in weight, and that the connecting rods I8 and I9 are connected so that their lines of action are substantially through the center of gravity of each one of them.

In the modified form of construction shown in Figs. 6, 7 and 8, the actuating shaft instead 55portion 25. The center line of theeccentric portion 26 is denoted by the line B. An eccentric bushing 21 is mounted on the end of theshaft 25 adjacent the eccentric portion y25, and the center line of the eccentric bushing 21 is denoted by the line C. The eccentricities of theportion 28 and ofthe bushing 21 are thus opposed. 'I'heeccentric portion 26 is iournalled in thebearing 28 which in turn is mounted in thehousing 29. Laminatedspring connecting rods 30 lead from thehousing 29 to the upper screen frame 2' and similar connecting rods ,Si lead from thehousing 25 to the lower screen frame 3'.

The eccentric bushing 21 on thedrive shaft 25 is journalled by means of thebearing 32 in the housing Il. Rigid connectingarms 34 extend from the housing -32 to therubber mountings 35 which in turn are mounted upon the supporting frame l'. Tie bars I5 connect the rubber mountings or the ends of the connectingarms 34 on opposite sides of the screenframe I'.

A drive sheave pulley 51 and aily wheel 35 are mounted upon thedrive shaft 25. The center line of the pulley I1 and of theily wheel 32 is indicated by the line D, which substantially coincides with the center line A of thedrive shaft 25. serrated v vebs 39 are provided on theily wheel 38 for the adjustable location of balance weights such as indicated at 40.

In the last described form of construction it will be seen that the center of rotation of thedrive shaft 25 is midway between the center lines ofeccentric portion 26 and of the bushing 21, so that under high-speed rotation the resiliently supported housing 23 will gyrate in a circular or approximately circular path, and the reactions in its resilient supports, viz., therubber mountings 35, will at all times balance the reactions in the complementary resilient supports I' and 5' of thescreen frames 2 and 3' respectively, thus eliminating any tendency of these resilient reactions to be transmitted to the supporting frame l and cause Vibration in the latter. Accordingly, the resiliency of therubber mountings 35 and of the rubber mountings 4' and 5' should be substantially equal, or alternatively, the relative eccentricities of theeccentric portion 25 and of the bushing 21 should be made proportional thereto.

Therefore, in the last described form of construction, there is provided a gyratory body, con-- sisting of thedrive shaft 25 and its attached parts which generates forces in its resilient supports to balance the complementary reciprocating yforces generated in the resilient supports of a plurality of screenframes or bodies having substantially straight line motions.

It should be obvious to thoseskilled in the art that more than two screen frames could be assembled in an apparatus embodying the principle of my invention, as long as the angular displacement of each of the reciprocating bodies or screen frames with reference to the others is properly determined. For example, three screen bodies could be assembled and operated from a common drive shaft if the conn ting rods were spaced 120 apart.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

l. In a reciprocating screen mechanism, the combination of a pair of symmetrically disposed screen bodies of substantially equal mass, a supporting member, said screen bodies being resiliently mounted on said supporting member, a drive shaft having eccentric portions,.a member Journalled on said eccentric portion 0f the drive shaft, a set of connecting rods rigidly secured to said member and rigidly connected to one of said screen bodies, a second set of connecting rods rigidly secured to said member and rigidly connected to the other of said screen bodies, said second set being disposed at an angle of 90 to the first set, and a counterweight carried on said shaft and of suilicient mass and so positioned as to balance the resultant vector sum of the forces transmitted through said connecting rods.

2. Ina reciprocating screen mechanism, the combination of a pair of symmetrically disposed screen bodies of substantially equal mass, a supporting member, said screen bodies being resiliently mounted on said supporting member, a drive shaft having eccentric portions, sets of connecting rods disposed at an angle of 90 to each other, one set of said rods rigidly secured to one of said screen bodies and the other set rigidly secured to the other screen body, means for operatively connecting said rods to said eccentric portions of said shaft, the connection between said rods and said means being rigid, and a counterweight carried on said shaft and of suiilcient mass and so positioned as to balance the resultant vector sum of the forces transmitted through said connecting rods.

3. In a reciprocating screen mechanism, the combination of a. pair of symmetrically disposed screen bodies of substantially equal mass, a supporting member, said screen bodies being resillently mounted on v said supporting member, a drive shaft having eccentric portions, a member journalled on said eccentric portion of the drive shaft, a set of resilient connecting rods rigidly secured to said member and rigidly connected to one of said screen bodies, a second set of resilient connecting rods rigidly secured to said member and rigidly connected to the other of bodies, said second set being disposedy at an angle of 90 to the rst set, anda counterweight carried on said shaft and of suilicient mass and so positioned as to balance the resultant vector sum of the forces transmitted through said connecting rods.

4. In a reciprocating screen mechanism, the combination of a pair of symmetrically disposed screen bodies of substantially equal'mass, a supporting member, said screen bodies being resiliently mounted on said supporting member, a drive shaft having eccentric portions, a member journalled on said eccentric portion of the drive shaft, a set of connecting rods rigidly secured to said member and rigidly connected to one of said screen bodies, a second set of connecting rods rigidly secured to said member and rigidly connected to the other of said screen bodies, said second set being disposed at an angle of 90 to the first set, each set of connecting rods comprising spaced resilient arms mounted on opposite sides of the shaft, and a counterweight carsaid screen of the forces transmitted through said connecting rods.

5In a reciprocating screen mechanism, the combination of a pair of spaced screen bodies, a supporting member, said screen bodies being resiliently mounted on said supporting member, a drive shaft having journal portions operatively eccentric to the center of revolution of said shaft, sets of connecting rods disposed at an angle of 90 to each other, one set of said rods rigidly secured to one of said screen bodies and the other set rigidly secured to the other screen body, means for operatively connecting said rods to said eccentric portions of said shaft, the connection between said rods and said means being rigid, and counterweight means carried on said shaft and of sufficient mass and so positioned as to balance the resultant vector sum of the forces transmitted through said connecting rods.

6. In a reciprocating screen mechanism, the combination of a pair of spaced screen bodiesa supporting member, said screen bodies being resiliently mounted on said supporting member, a drive shaft having journal portions operatively eccentric to the center of revolution of said shaft, sets of connecting rods disposed at an angle of to each other, one set of said rods connected to one of said screen bodies and to a journal portion of said shaft and the other set of rods connected to the other of said screen bodies and to said journal portion of said shaft, said connections permitting oscillatory motion of said connecting rods, and a counterweight carried on said shaft and of suicient mass and so positioned as to balance the resultant vector sum of the forces transmitted through said connecting rods.

7. In a reciprocating screen mechanism, the combination of a pair of symmetrically disposed screen bodies of substantially equal mass, a supporting member, said screen bodies being resiliently-mounted on said supporting member, a drive shaft having eccentric portions, sets of connecting rods disposed at an angle of 90 to each other, one set of said rods connected to one of said screen bodies and to said eccentric portions of said shaft and the other set of rods connected to the other of said screen bodies and to said eccentric portions of the shaft, said connections permitting oscillatory motion of said connecting rods, and a counterweight carried on said shaft and of sufficient mass "and so positioned as to balance the resultant vector sum of the forces transmitted through said connecting rods.

8. In a reciprocating screen mechanism, the

-combination of a pair of symmetrically disposed screen bodies of substantially equal mass, a supporting member, said screen bodies being resiliently mounted on said supporting member, a drive shaft having eccentric portions, a member journaled on said eccentric portions of the drive shaft, a set of connecting rods secured to said member and connected to one of said screen bodies, a second set of connecting rods secured to said member and to the other of said screen bodies, said second set being disposed at an angle of 90 to the first set, and a counterweight carried on said shaft and of sufficient mass and so proportioned as to balance the resultant vector sum of the forces transmitted through said connecting rods.

WALTER J. PARKS.

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