US1280269A - Reciprocating mechanism. - Google Patents

Description

C. L. MILLER.

RECIPIROCATING MECHANISM.

APPLlcAxoN FILED Nov. lo. 1911.

0mm 1 9 1 L L@ 0 d ma Mgg* CHARLESL. MILLER, OF SCOTTDALE, PENNSYLVANIA.

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Specification of Letters Patent.

Patenten, oct. i, iam..

Application led November 10, 1917. Serial No. 201,286.

To all 'whom'z't may concern.'

Be it known that I, CHARLES L. Minnen,

' a citizen ofthe United States of America,

the opposite direction.

and resident of Scottdale, in the county of Westmoreland and State of Pennsylvama, have invented a certain new and useful Improvement in Reciprocating Mechanism, of

which the following is a true and exact/de-` In carrying out my invention I employy -a plurality of systems of revolving bodies which I ordinarily mount directly on the screen or other body to be vibrated. Each system consists of. one or more bodies revolving with the same angular velocity' which is different from that at which the body or 'bodies vforming the other system or systemsV revolve. Each of these revolving bodies is mounted to revolve about an axis laterally displaced from the center of gravity of the body. The eccentrically mounted weights 0f the two systems are so relatively arranged and rotated that the maximum joint centrifugal .effect of the various revolving bodies in one of the two directions of movement permitted the screen or other body to be vibrated will be reater than the maximum 'oint centrifuga effectV of the bodies in t e opposite dlrection. In consequence the maximum acceleration given to the vibrating screen or like device will be greater in one direction than the other. This tendsA to'move particles supported by the screen or like object progressively in a direction opposite to that in which the acceleration of the screen or like object is most rapid.

In a simple preferred 'mode of carrying out my invention each system of revolving bodies comprises two similar eccentrically mounted weights rotating in opposite direcform y a Iparttions and each exerting its maximum centrifugal eii'ect along the line of movement of the screen or like'vibrating body at the same instants and in the same direction, and I revolve the two lbodies forming one system with half the angular velocity of the bodies 'forming the other system. A desirable consequence of employing two similar op ositely rotating wei hts 1n each system is t at the components o the centrifugal pulls of the weights in a direction transverse to the line of movement of the screen may thereby 'be balanced.

The variousl featuresof novelty which characterize my invention are pointed out with particular'ity in the claims annexed heretov and forming a part of this specification. For a better understanding of my invention, however, and the 4advantages possessed by it reference should be'had to the accompanying .drawings and descriptive` matter in which I have illustrated and described a preferred embodiment.

Of the drawings: y

Figure 1 is an elevation of a shaking table actuated by my novel vibration producing means.

Fig. 2 isfa plan view on a larger scale of a portion of thev shaking table shown in Fig. l. j

Fig. 3 is a section taken on the line 3 3 of Fig. 2.

' Figs. 4, 5,6 and 7 are diagrammatic viewsV illustrating the different relative positions of the revolving weights at successive'interva-ls.

Figs. 8, 9, 10 and 11 are force diagrams showing the centrifugal forces acting 1n the di'rection'of movement of the table exerted by the revolving weights in the positions of the latter shown in Figs. 4, 5, 6 and 7 respectively. l

In the drawings, A represents the shaking table proper, which, as shown, is sup- .ported by hangers B, pivoted at their upi after moving over the latter is discharged ,through lthe outlet A8.

The mechanism for giving th e shaking table its vibratory motion comprises a palr of revolving members F and F journaled on a vertical shaft E, which is shown as secured at its ends in the skeleton frame members D and D- secured to the shaking table proper. The members F and F', in the form'shown, are similar gear wheels provided with peripheral gear teeth which mesh with the peripheral gear teeth of gear wheels G and G journaled on a vertical shaft E also mounted in the frame members D and D. The members F and F arealso formed with bevel gear teeth on their ad-` F carries a similar andsimilarly mounted weight I. As shown, each of these weights is secured to the wheel carrying it by a bolt weights J, each secured in place by a corresponding bolt J2. Similarly the wheel G carries a pair ,of weights J', each of which is secured in place by a corresponding bolt J2. Each of the gear wheels G and G has half as many gear teeth as each of the gear wheels F and F', so that the wheels G and G' revolve with double the angular velocity of the wheels F and F. The various wei hts I, I', J and J', as shown, are so relatively positioned on the corresponding gear wheels that when the latter are in the relative positions shown in Figs. 2 and 3 the center of gravity of the weight I and of the two weights J are in the same vertical plane passing through they axes of the shafts E and E and on opposite sides of said axes, while the centers of gravity of the weights I and of the two weights J also lie in the same plane and on the opposite sides of the axes.

When the shaft H is rotated, the gear wheels F and F' are rotated in opposite directions with the'same angular velocity. As the wheel F rotates, the weight I passes successively through the positions relative to the shaft E, illustrated in Figs. 4, 5, 6

and 7. In the positionsillustrated in Figs.

4 and 6 the weight I' lies immediately beneath the weight I. In the intermediate positions shown in Fi 5 and 7 the weights I and I lie on opposlte sides of their com- The wheel G in the form shown car` ries two similar.. eccentrically mounted mon axis of rotation. The weights J and J vary their positions with respect to their common axis of rotation in a manner simi- .lar to that in which the weights I and I' in ig. 6 the full centrifugal effect of the' two weights I and I is to theright and the lso full centrifugal e'ect of the weights J and J is in the same direction.

In all :positions of the weights I and I', except those in which the weights have their centers of gravity in a line passing through the axes of the shafts E and E', the centrifugal pulls ofthe weights I and I', will include components transverse to the said line, but the transverse components of the centrifugal .forces exerted by the two weights will always be equal and opposite. Similarly the centrifugal forces exerted by the weights J and J will include components transverse to the line of movement permitted the table, which are equal and opposite. In consequence, these various transverse components do not tendto give the table any movement of translation transverse to its permitted and intended line of movement.

` In the diagrammatic Figs. 8, 9, 10 and 11, z' represents the resultant of the components of the centrifugal forces to the weights I and I in a direction parallel to the line of movement permitted 4the table, and j represents the component in the same .direction of the centrifugal forces exerted by the weights J and J In each of these figures, j re resents the resultant of the centrifugal orces exerted on the table by all of the revolving weights I and I' and J and J'. As these diagrams make clearly apparent, 4the maximum value of j .occurs when and only when the weights are in the positions shown in Fig. 6. Wlth the weights 1n the positions shown in Fig. 6'the full centrifugal pull of each is to the right. With the maximum value of the component much larger than the maximum value of j, as indicated in the diagrams, the Amaximum resultant centrifugal pull of the weights to Ithe left will occur when the wei hts are\in the position shown in Fig. 4. ith certain smaller maximum values of z' relative to the maximum value of j the maximum pull to the right will occur when .the weights are near the positions occupied by them in Fig. 7, as will be readily apparent to those skilled in the srt. less of the relative masses of the weights and their eccentricities the maximum centrifugal Regard! Lacasse pull exerted by them along the path of movement of the table will be greater 1n one direction than in the other.

With the particular mounting for the table described the table swin upward in each direction from the position occupied by it when at rest'and the acceleration ofthe table roduced by the centrifugal forces is modi- Eed by the action of gravit to a slight extent. Furthermorawhen t e material supported by the table starts to slide, as hereinafter explained, the relation between the centrifugal pull or accelerating force, and the acceleration which it gives the table is slightly modified. In general, however, the acceleration of the table at an instant will be in the 'saine direction as, an directly proportional, or approximatel so, to the comonent of the resultant o the centrifugal orces ofthe various weights I, I', J, and acting in the direction of movement permitted the table at that'instant. In consequence the arrangement described insures a maximum acceleration of the table in one direction greater than the Inaxirnumacceleration of the table .in the opposite direction. It will be understood, of course, that I use the h term acceleration in its generic sense to designate a change in velocity .regardless of whether the change` in velocity is an increase or decrease.

.The movement of the shaking table in either of the two directions of movement permitted it, tends to impart similar movements to,free particles supported by the table. :The extent to which these particles share the reciprocatory movements of the table depends upon the character of the contact friction between the particles and the table, and the acceleration of the latter. With the table horizontal, and with any usual contact friction, slow reciprocatory movements of the table will be shared bythe particles supported thereby. As the speed of lreciprocation increases a point will be reached at which the acceleration of the table duringa portion of the time required for each complete reciprocationl of the table will be so great that the inertia of the parti cles tending to prevent them from sharing the changes in velocity of the table, overcomes the frictional force tending to cause the particles to travel with the table.

With the table horizontally disposed similar reciprocatory movements, with similar rates of acceleration of the table made rapidly enough to prevent the particles from fully sharing these movements, would simply caiise the particles to slide back and forth on the table, and would not give them any progressive movement along the table or screen in either direction. Where, however,V

as in accordance with the present invention, the maximum. acceleration lof the table is greater in one direction than iii the opposite may direction the particles maybe given progressive movements in one direction over the table by reciprocatory movements of the table caused by the centrifugal effects of the revolving weights. The direction of ro'- gressive movement of the particles wil of course, be opposite to the direction of movement of the screen in which the acceleration is most rapid.

The character of the progressive movementof the particles over the table may be varied, of course, by inclinin the table to the horizontal. While the tab e must necessarily be generall horizontal, a suitable proportioning of tlie parts and of speed of operation may be employed to give the particles a desired progressive movement in one exerted b the weights I and I on the oneA hand, an the weights J and J on the other hand. This variation may readily be obtained by varying the distancebetween the centers of gravity of the two weights J, and similarly varying the relative positions of the two weights J. For this purpose each of the wheels G and Gr" is formed with a series of bolt holes, Gr2 to receive the`bolts J 2, by which the weights J and J are secured to their carrying Wheels. The spreading of the two weights J and J thus made possible operates in the same way as would a reduction of the masses of the two weights or an adjustment of the centers of gravity of the Wei lits toward their axis of rotation.

T e arrangement described for securing the weights J and J to their supporting wheels also makes ossible a change in the phase relation. of t ese weights relative to the weight J may occupy a position slightly behindthat in which lthe weight J is shown in Fig. v6. Adjustments if this character e necessary to under differing operating conditions, and particularly in handlingmaterials havin different coefficients of contact friction wit the table. These hase adjustments of the weights tendto displace or shift the ortions of the movements of the table in wii the particles slip over the table. With the ich progressive motion of translation of the llOlll lll() get the best results particular setting of the weights illustratedin the drawings, slippage of the particles to theleft commences somewhat before the table completes its movement to the left and continues during the initial portion of the movement of the table to the right. Inother words, with this setting, the sli page is started by so suddenlyarrestmg t e movet the table from beneath t e l articles.

. weight J wi ment of the table to the left that the particles overrun the table, 'and is continued during` the initial portion of the movement of the tableto the'right b in effect jerklng shifting the weights so that w en the weight I is in .the 1posltion shown in Fig. -6 the in order to avoid unbalanced transverse comlso ponents when the v'weig'htsJ are adjusted Arelatively to the weight I the weights J must also be so adjusted that the weights J and J will still cross the plane, including the axes of the shafts E and E at the' same instants..

In general the revolving weights should be so pro ortioned with regard to their masses, thelr eccentricities, and their speeds of revolution that slippage between the table and the material sup orted by, and progressivell moved over't e latter will occur in one irection only, though where much agitation of material is required a small slippage in one direction and a greater slippage 1n the opposite 'direction may not be undesirable. In general also the arts should be so proportioned and adjuste as to avoid more abrupt chan es in acceleration than are required to fro uce the desired agitation and sllppage o the particles over the table, since the more violent the changes in acceleration, the greater are the shocks and wear thereby given the table and its operating mechanism, and in general the greater the power consumption required for a given useful effect. i

With the mechanism described the progressive movement imparted to the material in one direction tends to produce a displacement of the table'in the opposite direction. This tendency must be counteracted in some'wa With the particular mechanism descri edit is. counteracted'by ravity, the tendency to progressively shi t the table to the left merely causing the left hand end of the path ofi movement of the table to be farther awayfrom, and higher above the position of fthe. table when the parts are at rest, than is the ri ht end of the path of movement of the tab e.

- While in accordance with the provisions Byv occupy a position somewhat' of. the statutesv I have illustrated'and described the best form of my invention'now known to me, it will be apparent to those skilled in the art that changes may be made in the form of my inventlon without departing from. its spirit, and that some features of my invention may sometimes be used to advantage without a corresponding use of other features of the'invention.

HavingD now described my invention, what I claim-as new, anddesire to secure by Letters atent, is: p

1. The -combination with a body to be vibrated, of means for vibratin lit consisting of a pair of eccentrical y mounted weights revolu-ble about parallel axes, a secf ond pair of eccentrically mounted weights- `revoluble about axes parallel with one another and means for rotating the two weights of the first mentioned pair with the same angular velocity butin opposite directions,

and for rotating the other weights in .opposite direction and each at double the rst mentioned an lar velocity.

2. The com ination with a body to'be v ibrated, of means for vibrating it ,consisting of a pair' of eccentrically mounted weightsV revoluble about parallel axes, a second pair of eccentrically mounted weights revoluble about axes parallel with one another, means for rotating the two weights of the first mentioned locity but 1n opposite directions, 'and for rotating the other weights in opposite direction and eachat double the iirst mentioned angular velocity, and means'for varying the centrifugal eiiect of one system relative to the other.

3. 'In combination a body free to move back and forth, means for impressing-forces thereon tending to give said body to and fro movement comprising two systems of revolving weights mounted onsaid body, each of said welghts being laterally displaced from its axis ofrotation, and each system consisting of `one or more weights, means for revolving each weight of lone system with one angular velocity, and for revolving each weight of the other system with an angular velocity which is an even multiple of the first mentioned velocity, said weights revolving in such phase relation lthat the maxiair with the same angular vei, Leone@ placed lfrom its axis of rotation, and eech system consisting of one or more weights,

means for revolving each Weight of one sys- 'tem with one angular velocity, and for revolving each weight of the other systemv with enl angular velocity which is an evenl mltiple of the first mentioned velocity, seid weights revolving in ,such phase' relation that `falle mirnum resultant; component in one direeion ,of movement Iof lthe body of the centrial forces exerted by `ell of the said revolving weights is greater then the maximum resultent'component of the centrifugal forces exerted by all of said weights in the opposite direction.

CHLES L. MILLER.

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