US2288963A - Driving connection - Google Patents

Description

July 7, 1942. H. VON TAVEL DRIVING CONNECTION 4 Sheets-Sheet 1 Filed Oct. 29 1941 wwwwww July 7, 1942. H. VON TAVEL 2,288,963

DRIVING CONNECTION Filed Oct; 29, 1941 4 Sheets-Sheet 2 Fig.5

July 7, 1942. VON TAVEL 2,288,963

DRIVING CONNECTION Filed 001:. 29, 1941 4 Sheets-Sheet 5 K ll/Ill July 7, 1942. H. VON TAVEL 2,288,963

DRIVING CONNECTION Filed Oct. 29, 1941 4 Sheets-Sheet 4 aa mbm 215g Patented July 7, 1942 Application October 29, 1941, Serial No. 417,040 In Switzerland August 27, 1940 3 Claims.

Th present invention relates to a driving connection adapted to operate a rectilinearly reciprocable member by means of a shaft revolving on an axis or the like. Moreparticularly, the invention is concerned with an improved driving connection "between the reciprocable piston and the power driven revolving shaft of a plunger machine, said revolvingshaftcarrying an eccentric on which revolves with the same angular speed in the oposite direction a second eccentric having the same eccentricity and being supported in the reciprocable member.

In known driving connections of this class both eccentrics are formed by crank pins, and the crank associated with the pin which provides the second eccentric is connected to a gear wheel rolling on a stationary internally toothed gear ring, the diameter of the pitch circle of said gear ring being twice the diameter of the gear wheel. The eccentricity of each of the crank pins must therefore equal the radius of the pitch circle of the gear wheel. But the radius of said circle has a minimum length which is determined by the required mechanical resistance and the conditions of engagement, and the above construction is, therefore, not adapted for drives wherein the reciprocable member operates with small throws as compared with the amount of eiforts to be transmitted.

It is an object of the invention to greatly simplify and cheapen the construction of such driving connections as well as to secure greater reliability of performance and an economy of space, by employing eccentrics instead of crank pins as heretofore.

Another object of the invention is to provide means for so coupling the movable parts of the driving connection as to adapt said'connection to drives operating with a relatively small throw of the reciprocable member while transmitting rather high efforts to or from said member.

With these objects in view, the invention resides in those novel features of construction, combination and arrangements of parts which will be hereinafter first fully described, and then be specifically pointed out in the appended claims, reference being had to the accompanying drawings, illustrating, by Way of example, two preferred embodiments of the invention.

In the drawings:

Fig. 1 is "a longitudinal section taken on the lines AA in Fig. 2. of a driving connection according to the first embodiment of the invention.

Fig. 2 is a cross sectional view taken on the line 3-3 in Fig. 1 and Fig. 3 is a horizontal section taken on the line CC in Fig. 1; Figs. 4 and 5 are cross sectional views taken respectively on the lines DD and E-E in Fig. 1 showing the same driving connection.

Fig. 6 is a cross sectional view taken on the line F-F in Fig. 1 showing a part of the said driving connection.

The Figs. '7 to 11 represent each schematically a sectional view of essential parts of the said driving connection in different positions.

Fig. 12 is a longitudinal section taken on the line GG in Fig. 13, showing a driving connection according to the second embodiment of the invention.

Fig. 13 is a cross sectional view taken on the line HH in Fig. 12 of this second embodiment.

Fig. 14 showsa horizontal section taken on the line KK in Fig. 12 of a part of the said connection.

Figs. 15 to 18 are cross sectional views similar to Fig. 13 showing a part of the connection, the

movable members being represented in different positions.

The driving connection represented in Figs. 1 to 11, comprises 'a shaft 2 turning about the axis l and supported in bearings 3 and 4. The bearings are preferably constructed of two halfsections provided respectively in the upper casing part 5 and the removable lower casing part 6 of the driving connection. The shaft 2 is provided with an eccentric I formed integral therewith and having its working surface 8 concentrically disposed relative toaxis 9, the latter beingspaced from the axis 1 at, a distance equal to the eccentricity e1.

On the working surface 8' of the eccentric l is seated a second or outer eccentric Hlhaving a working surface 'I I concentric to'the axis I2; the eccentricity of the eccentric I'G, that is the distance eg between the axes 9 and I2 of its inner and outer working surfaces, is equal to the eccentricity e1 of the inner eccentric I.

The outer eccentric I0 is held against axial displacement, on the one side, by a collar 13 fast with the inner eccentric I and, on the other side, by a distance sleeve l4 interposed between said eccentric and the inner end face of the bearing 4. Since the outer periphery of the flange l5 of the sleeve l4 has its center on the eccentric axis 9, the sleeve must be held against rotation on the shaft I, and this is conveniently effected by means of a pin l6 seated in said shaft and engaging a slot ll of the sleeve.

The outer eccentric I6 is itself mounted in a solid eccentric strap l8 which is shown having a pin l9 projecting into a rectilinear guide slot 28 provided in the lower casing part 6.

The numeral 2| designates two pistons of a plunger machine, 1. e. a pump, which are both of equal size and symmetrically disposed as to the axis of the shaft 2. Said pistons are reciprocable and fit comparatively snug within two cylindrical bores 22 of the upper casing part 5 which are shown communicating with each other by means of a duct 23 in said casing part.

The lower end of each of the pistons is shown forming a head 24 set laterally into a slot 25 of the eccentric strap I8, said slot having an inverted T-shaped transverse formation. There is no play between the piston heads 24 and said slot, neither in the upward or downward direction nor in the direction parallel to the axis of the working surface II; the pistons 2| thus partake of the up-and-down movement of the eccentric strap and prevent said strap from axial displacement on the working surface I I.

On the driving shaft 2, adjacent the bearing 3 is fixedly mounted a bevel gear 26 by means of a key 27. Opposite this gear is mounted a second bevel gear 28 which is freely rotatable on the shaft 2, the pitch and number of teeth of said second gear wheel being equivalent to the pitch and number of teeth of the bevel gear 26. Between the bevel gear 28 and the inner eccentric I is interposed a distance sleeve 29 seated on the shaft 2.

The bevel gears 25 and 28 are shown meshing with an intermediate bevel gear 38 which is fixedly mounted by means of a key 32 on the shaft 3| extending perpendicularly to the driving shaft 2 and supported in the upper casing part 5. A cap screw 33 prevents the bevel gear 38 from axial displacement.

The shaft 3| may be used for driving an auxiliary apparatus, i. e. a gear pump 34 sucking liquid from a tank 35. Said gear pump comprises a gear wheel 36 keyed to the shaft 3| and which meshes with a second gear wheel 31 journalled on a stud 38 extending parallel to the shaft 3| (see Fig. 3). Both said gear wheels closely fit the gear pump casing on their side faces and over a considerable portion of their circumferences, so that when driven, they suck liquid from the tank 35 through the supply pipe 39 into the gear pump casing and displace said liquid to a delivery chamber 4|] in said casing. From the delivery chamber 49 the liquid flows through a duct 4| in the gear pump casing into a conduit 42 and from there through a filter 43 into a conduit 44 leading to the duct 23 of the cylindrical bores 22 in the casing part 5. Upon upward stroke of the pistons 2| the admission of liquid in the cylinders 22 is interrupted and liquid is pressed through the check valves 45 into the delivery piping 46.

The bevel gear 28, which by reason of the intermediate gear wheel 30 has to turn with the same speed and in the opposite direction as the bevel gear 26, is rigidly coupled with the outer eccentric I8 by means of an intermediate disk 53.

The said disk has on its side facing the bevel gear 28 two square projections 54 disposed diametrically opposite each other and engaging with a corresponding slot 55 extending diametrically on the backside of the bevel gear 28; the disk 53 is thus displaceable in this slot relativeto the said bevel gear, perpendicularly to the axis of rotation and, at the same time, partakes of the rotation of said gear. On the side of the disk 53 looking towards the eccentric I0, there is provided a slot 56 extending along a diameter which is perpendicular to the diameter connecting the projections 54. This slot'engages two projections of the eccentric Ill, lying on a diameter which crosses the axes 9 and I2 of the two working surfaces 8 and II respectively. The eccentric I9 is thus displaceable along this diameter perpendicular to the axis of rotation and, at the same time, partakes of the rotation of the disk 53. Consequently it is also coupled for rotation with the bevel gear 28, while being freely movable relative thereto in a plane perpendicular to the axis of rotation, this movement being possible in either direction as far as required to allow for rotation of the outer eccentric I8 on the inner eccentric I. The said movement generally causes a displacement of the intermediate disk 53 relative to the bevel gear 28, and also a displacement of the eccentric I0 relative to the intermediate disk 53, said displacements being perpendicular to one another.

The mechanism just described is in effect an Oldham coupling which, as well known, permits relative lateral displacement of two rotating bodies, but constrains them to rotate at equal angular velocities.

The Figs. 7 to 11 show schematically the movable members of the driving connection in different positions. The arrow 58 indicates the direction of rotation of the shaft 2 and the inner eccentric 7. The outer eccentric It then rotates in the opposite direction, that is in the direction of the arrow 59 with the same angular speed relative to the stationary casing 5, 6. The arrows BI) and GI may be engraved in the eccentrics I and I8, respectively, to indicate the angular position of the said eccentrics.

Fig. 7 shows the movable members in the position whereby the pump pistons attain the lower limit of their stroke. The axes I, 9 and I2 are then placed in one and the same vertical plane which is symmetrical to the pistons 2| In the positions shown in Fig. 8 the driving shaft has turned over angle a in the clockwise direction. The .axis 9 lies no more in the vertical plane intersecting the axis I and extending symmetrically to the pistons 2|. But since the angle ,8 over which the eccentric II] has turned about the axis 9 in counterclockwise direction corresponds to the angle ac, and since the distance e1 between the axes I and 9 is equal to the distance eg between the axes 9 and I2, the axis I2 lies again in the said plane. This is the case in any angular position of the driving shaft 2 and, consequently, the eccentric strap I9, which is concentric with the axis I2, reciprocates upon rotation of the shaft 2 in a rectilinear to and from movement in said vertical plane through the axis I, which is symmetrical to the pistons 2|, thereby entraining said pistons to follow this movement.

Fig. 9 shows the axes I and I2 coinciding with one another as soon as the angles a and p become right angles. In Fig. 10 the members are shown in a position wherein the pistons 2| have reached the upper limit of their stroke. The axis 9 then lies in the vertical plane intersecting the axis I, as well as the axis I2 movable in said plane. The latter of the said axes is then spaced at a distance e1+e2 above the axis I while, according to Fig. 7, it was spaced at the same distance below said axis. The total throw of the pistons thus equals four times the eccentricity of one of the eccentrics.

Finally Fig. 11 shows the position during the downward stroke of the pistons, the axes I and I2 coinciding with one another.

In the embodiment shown in Figs. 12 to 18 the outer eccentric I carries on its side facing the bevel gear I28 two pins I 42, the axes of which are parallel to the axes I, 9 and- I2. Upon each of said pins is rockingly mounted a lever I43 having each a toothed sector I 44; the toothed sectors I44 of the two levers are shown meshing with each other along pitch circle arcs of equal radius, the centers thereof lying in the pivots of the levers. The arms of the two levers I43 remote from the toothed sectors ltd are of equal length; they carry on their ends pins I45 whereupon are applied steering bars Hit of equal length; the opposite end of each of said bars is pivoted on a pin I i? fast with the bevel gear I28. The two pins Iii are disposed diametrically opposite each other on the bevel gear and their distance is approximately equal to the mean distance separating the pins M5 on the levers hi3.

Owin to the engagement of the toothed sectors Hi l the rocking movements of the two levers I43 relative to the eccentric Iiii! are equally opposed to each other, that is each rocking move ment of one of the levers causes a rocking movement of the other lever over the same angle in the opposite direction. Moreover, since the axes of the pins i 35 lie approximately in the plane intersecting the axes of the pins I i-2, the distance of the pins I 55 remains practically unaltered. They are, on the one hand, displaceable relative to the bevel gear I28 in a parallel movement to the said plane along the arcs of circle determined by the steering bars I 66. On the other hand, owing to their distance which remains practically constant the plane connecting their axes is displaced approximately parallel to itself with respect to the bevel gear. Also the plane intersecting the axes of the pins I42 may be allowed to move parallel to itself upon rocking of the levers I 33 about the pins I432; this parallel displacement occurs, however, in a direction which is perpendicular to the direction of the displacement of the pins I45 relatively to the bevel gear I23; the pins IM and therewith the outer eccentric it are, thus, freely displaceable, within certain limits perpendicularly to the axis of rotation I of the driving shaft 2 and, at the same time, are coupled for rotation with the bevel gear I23. The very small angular displacements which the eccentric mu may undergo relatively to the bevel gear I28 are due to the variation of the distance between the pins I45 during displacement of the eccentric Hi and thus depend upon said variation. For the rest, the embodiment of Figs. 12 to 18 will be the same as has been described relative to Figs. 1 to 11.

In Fig. 15 the movable members are shown in a position which they assume when the pump pistons 2| have reached the lower limit of their stroke. Figs. 16 and 17 show these members in two positions which they occupy during the upward stroke of the pump pistons, whereby in the position according to Fig. 17 the axes I and I2 are shown coincident with each other. Finally, in Fig. 18 the movable members are shown in the position corresponding to the upper limit of stroke of the pump pistons ZI.

It will be apparent from the Figures 15 to 18 that during rotation of the driving shaft 2 the deviation of the levers I43 and, hence, the variation of the distance between the pins hi are of minor importance and not apt to cause a measurable angular displacement of the eccentric I90 relatively to the pins I41 connected to the bevel gear I28.

From the foregoing, it is believed that the construction and advantages of the present invention ma be readily understood by those skilled in the art without further description, it being borne in mind that numerous changes may be made in the details disclosed without departing from the spirit of the invention as set out in the following claims.

What is claimed and desired to be secured by Letters Patent is:

1. A driving conn ction adapted to operate at least one rectilinearly reciprocable member by means of a rotatable shaft, comprising in combination an inner eccentric fast on said shaft, an outer eccentric rotatably supported on said inner eccentric and having an eccentricity equal to the eccentricity of said inner eccentric, a ring member rotatably supported by said outer eccentric and coupled to said reciprocable member for reciprocating therewith, guiding means for preventing rotation of the said ring member relatively to the axis of reciprocation of the reciprocable member, a driving member rotatable about the axis of said shaft, a coupling between said driving member and said outer eccentric serving to constrain them to rotate at equal angular velocities, while permitting displacement of the eccentric in directions transverse to the axis of rotation, and driving connections between said shaft and said driving member for rotating the latter at the same angular velocity as said shaft and in the opposite direction.

2. A driving connection adapted to operate at least one rectilinearly reciprocable member by means of a rotatable shaft, comprising in combination an inner eccentric fast on said shaft, an outer eccentric rotatably supported on said inner eccentric and having an eccentricity equal to the eccentricit of said inner eccentric, a ring member rotatably supported by said outer eccentric and coupled to said reciprocable member for reciprocating therewith, guiding means for preventing rotation of said ring member relative to the axis of reciprocation of the reciprocable member, driving member rotatable about the axis of said shaft, an Oldham coupling connecting said driving member with said outer eccentric, and driving connections between said shaft and driving member for rotating said driving member at the same angular velocity as said shaft and in the opposite direction.

3. A driving connection adapted to operate at least one rectilinearly reciprocable member by means of a rotatable shaft, comprising in combination an inner eccentric fast on said shaft, an outer eccentric rotatably supported on said inner eccentric and having an eccentricity equal to the eccentricity of said inner eccentric, a ring member rotatably supported by said outer eccentric and coupled to said reciprocable member for reciprocating therewith, guiding means for preventing rotation of the said ring member relative to the axis of reciprocation of the reciprocable member, a driving member rotatable about the axis of said shaft, a pair of rocking levers pivoted to the outer eccentric and meshing with one another to effect equally opposed rocking movements relative to said outer eccentric, two steering bars connected each to one of said rocking levers and pivoted to the said driving member so as to couple said outer eccentric for rotation with said driving member, and driving connections between said shaft and driving member for rotating said driving member at the same angular velocity as said shaft and in the opposite direction.

I-IESPER VON TAVEL.

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