US1500988A - Mechanism for converting rotary into reciprocatory motion - Google Patents

Description

July 8 1924-` 1,500,988

v R. GoLDscHMlDT MECHANISM FOR CONVERTING ROTARY INTO RECIPROCATORY MOTION Filed June 22. 1921 4 Sheets-Sheet 1 /f Wig 2. fig. 5, Z ,g i

July 8, 1924. f 1,500,988

R. GoLDscHMlDT MECHANISM FOR CONVERTING ROTARY INTO RECIPROCATORY MOTION Filed June 22, 192! 4 Sheets-Sheet 2 FIG. 5a.

July 8, 1924.`

R. GOLDSCHMIDT MECHANISM FOR CONVERTING ROTARY INT0 RECIPRocAToRY MoTIoN 4 Sheets-Sheet 3 Filed June 22 1921 Jaya/afar.' Mmmm MMM J/'fagt Juny s, 1924. 1,500,988

R. GOLDSCHMIDT MECHANISM FOR CONVERTING ROTARY INTO RECIPROCATORY MOTION Filed June 22. 1921 4 Sheets-Sheet 4.

RUDOLF GOLDSCHIM'IDT, 0F BERLIN, GERMANY, ABSIGNOB T0 DET TEKNBE FOR8GSAKTIESELSKAIE 0F CEARLOTTENLUND, DENMARK, A COMPANY 0F mnonsmsu non coNvERrI'Ne Ronny INTO BEcIPBocATonY nunon.

. application med June 22, 1921. serial No. 479,573.

To all 'wwm t may concem.'

Be it known that I, RUnoLF Gomsonum'r, a citizen of Germany, and a resident of Berlin, Germany, have invented certain new and i useful Improvements in Mechanism for Converting Rotary into Reciprocatory Motion, of which the following 1s a specification.l

This invention relates to certain improvements in or modifications of the mechanism described in the specification of my prior patent application No. 441097 of 29th Jan' uary, 1921, wherein reciprocation is imp arted to a reciprocatory member by a weight (or weights) carried on the outer part of a jointed arm pivoted on ,the .reciprocatory member, the outer part of sald arm bein so jointed to the inner art as to capable of complete rotation-a out the axis of the joint. The geometrical path of the centre of inertia of the weight is 1n s uch case of epicycloidal character, depending on the direction of rotation of the outer arm, the

' relative angular velocity and the relative lengths of the inner and outer parts of the arm.

The object of the present invention is to enable the weight to describe curved paths of different character..

In order that the invention may more clearly understood, reference is hereinafter made to the accompanying drawings, whereonzi Fig. 1 is a diagram of a common form of centrifugal mechanism. l

Figs. 2 and 3 are, views showing two p ositions of a form of mechanism described 1n myparent specification aforesaid.

Figs. 4 and 5 are views showing two positions of one form of mechanism according tothe present invention.

Fig. 5a is a side view at right angles to Fig. 5 showing a constructive form of the mechanism illustrated in Figs.' 4 and 5.

Figs. 6 and 7 are views corresponding to Figs. 4 and 5 showing a modified form of mechanism.

Figs. 8 and 9 are views corresponding to Figs.'4 and 5 showing the same applied tol eccentrics.

. Fig. 10 is a side view at right angles to Figs. 8 and 9 showing a constructive form thereof.

Figs. 11 and 12 illustrate different forms of driving mechanism hereafter referred to.

g to an inner arm S1 of equal sired surface lcan Fig. 13is a sectional view at right angles to Fig. .9.

Fig. 14 illustrates (in section) a modiication ofthe mechanismshown m Fig. 13.

Fig. 15 is a cross-section showing a still further modification.

Fig. -16 is a side view cfa form of mechanism hereafter described.

Throughout the drawings `the direction of rotation of the the arrows.

By reference to Fig. 1, it will be seen that a weight O carried on'an arm S pivoted at W describes a circle. If the weight O is carried by an outer arm S2 'ointed at W2 ength ivoted at W1, thevweight O may be gear to describe a straight line Z-Z (Figs. 2 and In Fig. 1 the operation of setting a body on which the arm S rotates, in reciprocatory motion, 1s produced purely by centrifugal force. As the centrifugal action takes place in all directions, the reciprocatory .movement of the body in a plane or on any deonly be regulated if the body V to be moved is either .positively guided or if a second oppositely rotating centrifugal weight is employed. In 2 and 3, the production of the alternating force on the body V de ends entirely on the acceleration and retar ation of the mass O, which roduces corresponding reacting forces on t e pivot W1. For convenience, the arrangement according to Fig. 1 will hereinafter `be designated a centri ugal gear and that according to Figs. 2 -and 3 a reaction gear, that isi to say a centrifugal action will be referred to if the centrifugal weight O or two oppositely rotating centrifugal weights carry out clrcular rotation relative to the body 'to be set in oscillation, whereas a reaction effect will be implied if the centrifugal weight (or weights) is subject to linear acceleration and retardation. `vIn the general application of the present invention producing epicycloidal movement, elliptical movement, or the like, both actions are combined.

In the case of the mechanism shown in Fig. 2 no positive guide or oppositely rotating weights are required for the reason that forces are not set up at right angles to the line ZZ, provided that the masses within the arms and bearings are practically parts are indicated by l small compared to the position shown 4 O1 and O2 'l l amuse mass of the weight O. Suilicient space must be provided at right angles to the line Z Z, for the movement of the arms 1 and S1 which are of equal length. Nevertheless the arms S1 and S2 are only half the length of the corres ndin arm S of the centrlfuga'l gear ig. 1. In order to utilize the rotary movement of the arm S1, a. weight O1 (as in Figs. 4 5 and 51), may be mounted on the arm S1, but then the length L2 of the arm S2 must be eater than the length L1 of the arm S1 an the weight O2 must be greater than the wei ht O1 when L2 is less than twice L1 if a uplicate set of opposltely rotating mechanism is to be obviated. If the weight O is rotated in one d1- rection and the weight O2 is rotated 1n the opposite direction at twice the angular velocity of O', then when O" moves from the in Fig. 5 through either 90 or 270 degrees, the arm S2 will overlap the arm S substantially as shown in Fig. `4f, where has turned through just over 270 degrees from the position s own in Fig. 5. The weights O and O2 may be so related to the length of the arms S and S2 that the moments of the weights balance each other when the arms S and S2 overla Thus, for-exam le, the weights O and 2 may be equal an the length L2 of arm S2 may be twice the length L of arm S. Then when the arms S2 and S overlap (substantially as shown in Fig. 4 the moments of the weights O1 and O2 will alance each other and there will be no tendency to move 'the pivot W1. If the pivot W1 is to be moved for any purpose (as, for example, if the pivot W1 is mounted on the wing of a vibrating wing iiying machine) the moments of the weights must be made unequal in the position referred to.

The arm S may be sub-divided into a lurality of jointed arms. Figs. 6 and 7 s ow a three-part armv in which the arms S3 and S2 are equal in length and the arm S2 twice the length of the arm S1. The wei hts O1 and O1 in this case are together equa to the weight O2, so that, in the overla ping position (substantially as shown in ig. 6) the moment of the weight O2 balances the combined moments of the Weights O1 and O1 whilst in the extended position (Fig. 7)v the combined moments are equal to twelve times the weiht of O1 or Ox1 multiplied by the length 1. l v

By increasing the diameter of the pivot W1, W2 etc. the mechanism may assume the form of an eccentric. Figs. 8, 9 and 10 show an arrangement which corresponds to Figs.

4, 5 and 51, in which the dimensions of the ivots W1 and W2 transform the mechanism into eccentrics andin which the weights O1 and O2 are integral with the arms S1 and S2 of Figs. 4 and 5. l

Whilst Figs. 8 9 and 10 arepmore suitable for apparatus which require to withstand the vio ent shocks of hammers and the like, the arrangements according to Figs 2 to 7 may be employed for devices whic have to carry out comparatively Alarge movements, free from shock, such as the wingsof vibratin wing flying machines.

In t e parent4 specification aforesaid, the driving means for the outer-arm S' may be chain-and-chain wheel mechanism 11 illustrates modified driving means. In i 11, a planet wheel A carried by the arm S1 and turning with the arm S2 is driven by a fixed wheel B.

In Fig. 5, the body V to be reciprocated slides in a guide block C on which is mounted apmot'or D. The motor shaft M is connected b a universal joint H to a flexible shaft I aving a universal joint connection K to the shaft W1 which rotates in the body V. The shaft W1 passes through a gear wheel L which'is fixed to the side of the bod V so that it does not rotate. The shaft WX carries the arm S1 which has a stud R supporting an idle gear wheel N which rotates between the gear wheel L and a gear wheel P iixed upon the shaft W2 which rotates in the wei ht O1 and carries the arm S2 and weight 2. The gear wheel N thus forms a planet wheel which turns around the lixed sun Wheel L and drives the outer wheel P.

In Fig. 10, the shaft W1 likewise rotates in the body V and passes through a ear wheel L fixed to the side of the body In this case, however, the shaft W1 is fixed excentrically to a. disc forming the weight O1 and to the side of the disc is fixed the stud R sipporting the planet Wheel N. The shaft 2 su porting the outer wheel P passes central y through the disc O1 and rotates therein. On the side of the disc O1 opposite to the wheel P, the shaft W2 is connected to the arm S2, the outer end of which is fixed to an eccentric forming the weight O2 and rotating on the disc O1.

In Fig. 12 'a crank T1 is provided which, by means of the connecting rod T2, sets the arm S2 in the desired rotation. The crank and connecting rod T1, T2 may be replaced by pin-and-slot mechanism as'e. g. by dispensing with the rod T2 and providing a longer crank T1 with a pin on the end thereof to slide in a groove in the arm S2- The arrangement shown in Fig. 12 may be adopted for multiple-divided arms such as shown in Figs. 6 and 7, thus obtaining a form of lazy-tongs device.

Fig. 13 shows an arrangement similar to Fig. 12 applied to eccentrics. The eccentric O1 is driven by the bevel wheel F and the eccentric O2 by the bevel Wheel E and crank T2. In this case, in order to obtain uniform angular velocity the distance between the centres of the crank pins is prefer ably made equal to the eccentricity and to avoid dead points a plurality of (say four) cranks T2 are distributed equally about the circumference.

I In Fig. 13 the forces produced by the ec' I centrics O1 and 02, which are to displace the body V, act thereon at a. oint outside the centre of gravity of the ody V, because the eccentrics O1 and O2 are unilaterally mounted on the axis W1. That is generally possible where, as in flapping wings, the body V swings about a pivot or the tendency ofthe body V tocarry out a rotational movement about its own centre of gravity is counter-acted by guides. If this is not the case, the eccentrics OL and Oa must be so arranged that their centre line passes through the centre of avity of the body V, in which case the axis W1 may be held in a fork. This fork, however, is not desirable if (as in the case of a hammer) the fork is liable to be highly stressed by shocks or to hinder the movement -of the eccentrics, 'should the latter be of considerable diameter. In 'such case the eccentrics O1 and O2 would preferably be sub-divided into two parts and these parts so disposed that their common centre plane passes throu h the centre of gravity o the body In order then todispense with separate driving. gear for the parts of the' eccentrics, the arrangement according to Fig. 14 may be adopted. In this case the axle W1 is made hollow and the separate eccentrics are connected together through the hollow axle W1 so that a single driving gear only is necessary and the se arate eccentrics co-act as a single one. T is arrangement is Vof fundamental importance and may be applied also where the eccentric AO2 is dispensed with, in which case a centrifugal gear is obtained.

Fig. 15 is a view in section at right angles to Fig. 14 in which the eccentrics O1 and O' are constructed as hollow chambers and in order to dis lace their centres of gravity as far as possi le outwardly,^two of the chambers P1 and P2 are lled with a heavy metal such Ias lead.

The turning moment which is necessary for driving the centrifugal weights or eecentrics varies very considerably through out one complete revolution, particularly with hammers where the arising shock also reacts on 'the weights. It is therefore desirable and in fact frequently indispensable, for the'protection of the driving ear, to interpose a means of storing energy etween the driving gear and the centrifugal weights, in the form of alspring or s rings, either a single spring or one for eac centrifugal weight.

Fig. 16 shows such an arrangement where a spring F (diagrammatically illustrated as ber and sub-divided into three or more parts jointed together, driving connections between the arm parts for rotating each arm part relative to the adjacent arm part, means for rotating the innermost arm part and a weight on the outer part of said arm.

2. Mechanism for converting rotary into reciprocatory motion comprisinga reciprocatory member, an arm pivoted to said member, means for rotating said arm, a weight carriedby said arm, an outer arm jointed to the outer end of the inner arm, means for rotating the outer arm relative to the inner arm and a weight carried by the outer arm.

3. Mechanism as s ecified in claim 1 having a weight carrie by each of the inner parts of the arm. l

. 4. Mechanism as specified in claim 2 1n which the inner and outer arms and weights are so related that the turning moments thereof substantially counter-balance each other when the arms are in overlapping positions.

5. Mechanism as s eciied in claim 1 having a weight carrie v by each of the inner parts 'of the arm and means for rotatin the parts 'relative to each other, the weights and arm parts being so related that the turning moments thereof substantially counterbalance when the arms are in overlapping positions.

6. IMechanism for converting rotary into reciprocatory motion comprising a reciprocatory member, an eccentric pivoted thereto, means for rotating said eccentric, a second eccentric rotatable on the first eccentric and means' for rotating the second eccentric on the first eccentric.

7. Mechanism as specified in claim 2 in which the outer arm `is driven by planet signature.

RUDOLF GOLDSCH'MIDT.

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