US2005917A - Means for the production of circular or elliptical oscillations - Google Patents

Description

G. LINKE June 25, 1935.

MEANS FOR THE PRODUCTION OF CIRCULAR OR ELLIPTICAL OSCI'LLATIONS Filed Dec. 14, 1932 2 Sheets-Sheet 1 June 25, 1935. G. LINKE 1 ION OF CIRCULAR OR ELLIPTICAL OSCILLATIONS Filed Dec. 14, 1932 2 Sheets-Shee t 2 MEANS FOR THE PRODUCT Patented June 25, 1935 PATENT OFFICE MEANS FOR THE PRODUCTION OF CIRCU- LAR OR ELLIPTICAL OSCILLATIONS Gerhard Linke, Magdeburg, Germany, assignor to I firm Fried. Krupp Grusonwerk Aktiengesellschaft, Magdeburg-Buckau, Germany Application December 14, 1932, Serial No. 647,291 In Germany December 19, 1932 6 Claims.

The present invention relates to the support of a body, for example a sieve, by means of springs or some other elastic medium which can yield in all directionsin one plane, to which body, by

means of a crank or a mechanism wherein there is generated an out-of-balance force, there is imparted motion in a circular or elliptical path so that each point on the body moves in a plane at right angles to the driving shaft. For the sake of brevity, such a motion in a closed path is referred to as a circular or elliptical oscillation. In the case of devices whose motion is caused by a crank drive, e. g. a crank shaft, it is quite easy to balance completely all centrifugal forces by arranging auxiliary masses eccentrically in relation to the main frame, since, in this way, the main and balancing masses both rotate about the same axis in the main frame and move in similar closed curves, for example circles or ellipses, the throws of the crank arms being related to one another inversely as the magnitudes of the masses. There remains, however, in the case of these arrangements a disadvantage in that there is no balancing of the weight of the oscillating mass, so that the springs are stressed more strongly in the direction of the gravitational force than in the other directions. In the case of the mechanism operated by out-of-balance devices, wherein in addition to the last-men tioned disadvantage, there further exists the difficulty of the balancing of the forces exerted by the masses because the shaft carrying the outof -balance discs is not mounted on the base frame but oscillates freely with the mass. In the case of these arrangements there consequently remains unbalanced the reactive pressure of the guiding springs which is caused by the oscillating masses and which must be taken up by the base frame.

It is the main object of the invention to avoid in a simple manner the disadvantages that occur in the case 'of the arrangements mentioned. This is attained by the fact that, in the case of both kinds of apparatus, the weight of the oscillating (Cl. Fl-61) with the out-of-balance driving device by means of a yielding coupling.

Some constructional examples of the subjectmatter of the invention are shown in the drawings, in which:

Figure 1 shows a side elevation of an apparatus driven by unbalanced masses,

Figure 2 shows a plan view of a modified embodiment of the apparatus shown in Figure 1,

Figure 3 shows a perspective view of an apparatus driven by an eccentric shaft,

Figures 4, 5 and 6 show details, and

Figure '7 shows, in side elevation, an apparatus mounted obliquely.

Referring to Figure 1, the mass I, which is 15 formed for example by a frame sieve, is mounted on springs 2 so as to be capable of oscillation in all directions in the plane of the paper. Through the centre of gravity S of the mass, there extends a shaft 3, which is mounted in the mass, and on the free ends of which discs 4, carrying the unbalanced masses U, are fastened.

When suchan arrangement is put into operation, the mass l is moved under the action of the unbalanced, masses out of its initial position 0 which it assumes in its position of rest, the mass then oscillating about its points of support in a closed path during the operation. The springs 2 being equally stiff in all directions in the plane of the paper, and consequently the spring reactive pressure being equally great in eachposition of the springs, and the weight of' the oscillating masses being neglected, a circular movement would then result-as indicated by the circles 5 in Figure 1. The centrifugal forces of the oscillating masses occurring during the operationnamely, the centrifugal force P of the mass I and the centrifugal force P of the unbalanced mass-cancel. The balance of the forces is, however, appreciably disturbed by the weight of the mass moving in the gravitational field of the earth, so that th oscillation curves become non-uniform; in addition there occur, according to experience, vibrations and particularly undesirable resonance phenomena. 45

In order. to avoid this disadvantage there are provided, according to the invention, supplementary springs 6 which, for the purpose of avoiding disturbing resonance phenomena, have as weak a characteristic as possible and are capable of carrying the weight of the mass I. By these springs the effect of the weight of the mass is diverted from the springs 2 so that they are stressed uniformly in all directions. v

In Figure 2, all the elements shown in Figure 1 are indicated in plan view. Additional members are also provided in this embodiment, the purposes of' which are explained hereinafter.

In the construction shown in Figure 3 the mass I is compelled to effect circular oscillations, in a way'known per se,-by means of a crank shaft of small eccentricity. As has already been mentioned, in the case of this mode of driving, a balancing of the centrifugal force of the mass I may be obtained by means of eccentrically arranged centrifugal masses, and, indeed, for this purpose there are provided balancing masses I, which revolve with a displacement of 180 in relation to the main mass I and are arranged on the portion of the eccentric shaft that is mounted in the base frame of the apparatus. The reactive pressure of the springs 2, supporting the mass I which acts on the base frame is in this case also balanced by the balancing masses I. The crank shaft 8, which runs in bearings 9 on the mass I and in bearings I0 on the base frame, extends likewise through the centre of gravity S of the mass I. The weight of the mass I is taken up by the springs II which are formed correspondingly to the springs 6 shown in Figures 1 and 2. When this apparatus is set in operation the mass I oscillates on the circle prescribed by the eccentric shaft. The centrifugal force P produced by the mass I is balanced by the centrifugal forces exerted by the balancing masses I. The reactive pressure of the springs 2 is likewise balanced by the forces of the centrifugal masses 1 through the base frame and the bearings I0.

If, on the contrary, the mass is, as in the case of the constructional example according to Fig ures 1 and 2, caused by unbalanced masses to execute circular or elliptical oscillations, the balancing of the centrifugal forces and the reactive spring pressure above mentioned cannot be produced without further steps, for the reason 'mentioned in the opening part of the specification. Ii order, nevertheless, to produce this result, according to the invention there is provided a balancing mass which is mounted so as to be capable of rotation but incapable of oscillation and which is driven by the shaft mounted in the oscillating main mass by means of a yielding coupling and which rotates with a displacement of 180 in relation to the unbalanced mass. The apparatus according to Figure 2 is provided with such balancing masses. The discs 4 are connected on each side by yielding couplings I2 with discs I3 which are mounted in the base frame and each of which carries a balancing mass I4. These balancing masses are displaced by 180 in relation to the unbalanced masses U and are-of such dimensions that the centrifugal forces produced by them are equal to the reactive pressure of the springs2. In this way the centrifugal forces are balanced in the base frame and the foundation of the apparatus remains free from the forces and the vibrations produced by them. For the couplings I2 there may be used leather strips or the like, which indeed in the case of eccentricity of the discs 4 in relation to the discs I 3 allow displacement of these discs parallel to one another, but prevent their relative rotation, so that the unbalanced masses U remain always displaced by 180 in relation to the balancing masses I4.

Instead of separate springs 6 or II for taking up the weight of the oscillating mass, the springs 2 or corresponding yielding means may be made beforehand in such a manner that they are stiffer in the direction of the gravitational force than in the other directions by an amount corresponding to the weight of the oscillating mass. In order to enable the springs to be easily adjusted to possible variations in weight of the mass, they are advantageously provided with a regulating device by means of which their initial stress can be altered. The movement of the springs under initial stress must be a multiple of their oscillatory movement if spring characteristic that is.

as weak as possible is to be produced. As compared with .the supporting springs hitherto employed in apparatus of a similar kind, the present spring device is a considerable improvement because in the case of. known springs it is not possible to make them stiffer in the direction of the gravitational'force than in other directions and also to obtain an exact adjustment of the springs in the case of weight variation of the masses. In Figure 4 there is represented a spring device adapted to yield in all directions in two planes that are at right angles to each other. There are arranged four helical springs of which the springs I5, I6, II are equally strong, whilst the spring I8, which acts in the direction of the gravitational force, is made correspondingly stronger to carry. the weight of the oscillatin mass.

In Figures 5 and'6 there is shown a rubber ring such as is known for the mounting of circularly oscillatory devices. In contradistinction to the hitherto usual kind, in:which such rubber rings exhibit the same strength in all directions, the rubber ring'according to the invention is so made that it also effects at the same time the balancing of the gravitational action of with initial tension into a steel ring 20, may have a stiffer mass of rubber over the sector 22 located under the axle M. It is also possible to make the rubber ring broader at this place than at the other places-as indicated in the lower cross-section shown in chain-dotted lines in Figure 6. In this way also the reaction of the rubber ring is increased in the direction of the gravitational force. a

In the case of an arrangement with an inclined oscillating mass, the means for balancing the weight of this mass must of course be arranged vertically as is shown in Figure 7. If the angle of inclination of the base frame is subject to alteration, there may advantageously be arranged on the base frame 23 arc-shaped guides 24. The lower ends of the springs 25, which are connected with the oscillating mass at their upthe springs are always vertical.

As a constructional example there has been mentioned a sieve arrangement. The described force and weight balancing device may, however, be applied to all kinds of apparatus that are compelled to execute circular or elliptical oscillations, as, for example, shaking troughs, packing machines, and the like.

What I claim is:

1. In an apparatus of the class described, a mass; means for imparting to said mass oscillations in a closed path; resilient means for supporting said mass having a substantially constant reactance to movement of said mass in all directions in a plane containing the closed path, in addition to a supplementary vertical reactance for neutralizing the gravitational force exerted by said mass; said supplementary vertical reactance being exerted by resilient means whose movement under initial stress is a multiple of its movement caused by oscillation of said mass.

2. In an apparatus of the class described, a mass, means for imparting to said mass-oscillations in a closed path, resilient means for supporting said mass having a substantially constant reactance to movement of said mass in all directions in a plane containing the closed path, and supplementary resilient means for neutralizing the gravitational force exerted by said mass, said supplementary resilient means having a movement under initial stress which is a multiple of its movement caused by oscillation of said mass.

3. In an apparatus oi. the class described, an inclined mass, an inclined support therefor, means for actuating said mass to impart thereto oscillations in a closed path, resilient means fixed on said support for carrying .said mass, said resilient means having a substantially constant reactance in all directions of movement of said mass in a plane containing the closed path, supplementary springs for supporting said mass to neutralize the gravitational force exerted thereby, are shaped guide members on said support,

one end of each of said springs being rotatable at a the point of engagement thereof with said mass and the other end being adjustable along said 5. The combination claimed in claim 1, wherein the resilient means consist of rubber rings for supporting the oscillating mass, wherein each rubber ring is increased in thickness over a. portion located in the direction of the gravitational force or the oscillating mass.

6. The combination-claimed in claim- 1, wherein the resilient means consist of springs for supporting the oscillating mass extending at right angles to each other, whereof the spring acting in the direction of the gravitational force is made stronger than the others to take up the weight of the oscillating mass.

GERHARD LINKE.

Images