GB2113348A - Oscillator for mechanical vibrations - Google Patents

Abstract

Relates to an oscillator having two unbalanced weights 34 which are arranged on parallel shafts 1, 2 and rotate synchronously in opposite directions with an infinitely adjustable relative phase position. Such oscillators are more especially used for the operation of continuously reversible vibrator plates. At least one of the unbalanced weights which is connected to the sun wheel 12 of an epicyclic gear with a spider 10 carrying the planet wheels 11 which is swivellable manually about the sun wheel by means of an adjustment device. An annulus 9 embracing the planet gears and the sun wheel is connected with the parallel shaft of the second and the effective diameters of the driving pulley 7 of the second shaft and of the internal gear are in the same ratio as the effective diameters of the sun wheel and the annulus. <IMAGE>

Description

SPECIFICATION Oscillator for mechanical vibrations The invention relates to an oscillator having two rotating unbalanced or eccentric members or weights on parallel unbalanced shafts and operated synchronously in opposite directions with infinitely adjustable relative phase through a drive train including an epicyclic or planetary gear train. Oscillators of this type are utilised particularly for driving continuously reversible vibrator plates.

Vibrator plates equipped with mechanical oscillators and with a sealing arrangement relative to the base determine, with the phase position of their synchonously operated unbalanced members or weights, both the running direction and also the running speed of the vibrator plate. Vibrator plates which are equipped with oscillators which can be switched as regards the phase position permit a switchable alteration of the running direction. Vibrator plates with infinitely adjustable phase position of the unbalanced weights of their oscillator are, however, distinguished by the possibility of adjusting, as desired, both the running direction and the running speed of the vibrator plate. Consequently, a number of oscillation are already known, with which the reciprocal phase position of the unbalanced members is capable of being varied by special gears.Thus, for example, in connection with the vibrator according to German Patent 94 59 17, the phase position of synchronously driven unbalanced members can be altered by interposition of two epicyclic or planetary gears, the spider of one gear being fixed and of the second is provided so as to be adjustable. This arrangement is both quite cumbersome and also undesirably costly.

In the oscillators according to German Gebrauchsmuster 1 841 635, one of two coaxially rotating unbalanced members or weights are operated by way of a differential gear constructed as bevel gears, the housing of the differential gearing being adjustable by means of a hand wheel. Two such bevel wheel differential gears are provided by German Offenlegungschrift 28 09 111, and at least one by German Offenlegungschrift 28 42 873.

These bevel wheel differential gears are also expensive to produce and take up considerable space which is highly disadvantageous, and the high axial pressures which occur in these are undesirable, as are also the high relative speeds of rotation which are imposed on the bearings. Because of these and also other disadvantages of the known oscillators, for example, their complicated structure and their high sensitivity to mechanical disturbance, German Offenlegungschrift 28 27 1 24 and also German Offenlegungschrift 29 09 204 disclose drive members which are displaceable mechanically or hydraulically and connect a longitudinal slot and a spiral groove of the unbalanced shaft and a bushing which enclose these latter and comprise the unbalanced weights, and a similar arrangement is already known from German Auslegeschrift 1 078 058.However, it has been found that, in addition to the complex structure and the undesirably high force requirement, even if the connection is achieved by way of an intermediate bushing, the arrangement necessitates an additional axial length, as a result of which the oscillator and thus the vibrator plate are undesirably made wider.

It is also know to couple the two unbalanced shafts by a sprocket chain or a toothed belt, which have in each of the top run and the bottom run, a loop which is formed by a deflecting roller and which can be reduced or enlarged in opposite directions. These deflecting rollers can be arranged on a common rocker arm, but the arrangement still involves an undesirably large space requirement and is undesirably expensive on account of additionally necessary chain tensioning means or the like. German Auslegeschrift 1 090 589 accordingly discloses coupling gear wheels which can be displaced by rocker arms, which wheels are, however, likewise unsuitable for oscillators which are to be of a compact construction.

The invention accordingly seeks to provide an oscillator of the type as initially referred to, which is capable of being compactly constructed, requires little maintenance and is reliable in operation, is of relatively low cost and has a broad range of adjustment. Accordingly the invention provides an oscillator having a mechanism including two rotating unbalanced members mounted on respective first and second parallel shafts which are rotatable synchronously in use, in opposite directions with relatively adjustable phase positions, wherein the shaft of at least one of the unbalanced members or weights is connected to a gear assembly including an annular gear having internal teeth which drive the unbalanced member via planet wheels and a sun wheel, and including a spider (10) supporting the planet wheels which can be rotated by an adjustment means.The annulus can in this case be constructed with a relatively small diameter and more especially a small axial length, and the planetary or epicyclic gear involves only moderate expense, by virtue of radial serrations or teeth which may be used with this compact structure. As a consequence, an uncomplicated construction is produced, which contains tested normal commercial machine elements and, while being of an inexpensive and compact construction, also permits the transmission of high output. Particularly when the connection is effected by toothed belts or sprocket chains, it is possible to have large spacings of the unbalanced shafts without any apparent increase in cost.

In a preferred arrangement the mutual phase position can, when desired, be altered through 360 , and the relatively small dimensions make it possible for the complete oscillator to be arranged without any difficulties in an common housing and thus in a manner so as to be protected from the dust which is often predominant at building sites, or the oscillator can be fitted directly on the vibrator plate, it being expedient only to cover the epicyclic or planetary gearing.

The sun wheel of the planetary gearing is preferably connected to one of the unbalanced shafts while the spider can be mounted on the unbalanced shaft, or on a housing attachment concentric with the shaft, a fixed bushing or an extension of the unbalanced member or weight.

The sun wheel of the planetary gearing is preferably connected to one of the unbalanced shafts while the spider can be mounted on the unbalances shaft, or on a housing attachment concentric with the shaft, a fixed bushing or an extension of the unbalanced member or weight.

The directly driven unbalanced shaft and the annulus of the planetary gearing driving the other unbalance shaft can be fitted with belt pulleys or sprockets and can be connected by means of a toothed belt or a chain.

Alternatively they may comprise gear wheels or ring gears and be connected to one another by way of an odd number of interposed gear wheels. The diameter of the gear wheel or chain wheel or respectively of the belt pulley of the unbalanced shaft end of the annulus will then preferably have the same ratio to one another as the diametr of the teeth of the sun wheel and of the annulus.

The adjustment means of the spider will be arranged differently depending upon the ac tual requirements and circumstances: It is for example possible to provide on the spider an eccentrically disposed pivot for a substantially axially displaceable adjusting rod of the adjustment means or mechanism. In another arrangement, the spider may be equipped with an external toothing covering at least a segment of the periphery. A cooperating axially displaceable adjusting rod of the adjusting mechanism has a rack which engages in the said toothing, the said rod being displaceable manually or by means of hydraulic cylinders.

Partial compensation of the torque reacting on the spider can be achieved by a spring which biases the adjusting rod, and the setting of the adjusted value can be achieved by a friction member engaging the adjusting rod and/or the setting means. A particularly broad range of adjustment may be achieved if the spider is constructed as a worm gear and the adjustment means comprises a worm which meshes with the teeth of the worm gear; for the purpose of producing a rapid adjustability, the worm is preferably made with multiple threads, or the worm and worm gear are provided with helical toothing.

A further possibility of adjustment, also with small angles of traverse of the spiders, can also be provided by means of symmetrical construction, in which each of the unbalanced shafts has associated therewith a planetary gearing, having spiders which are adjustable for acting in opposite directions. Rotation and swivelling movements of the vibrator plate may also be facilitated if at least one of the unbalanced weights is divided axially into two separate, independently mounted component weights, each of the component weights having associated therewith a planetary gearing which drives it and has an adjustment means acting on its spider.The adjustment means may be so designed as to comprise separate adjusting members one of which adjusts the spiders in the same direction and the other of which adjusts the said spiders in opposite directions, or it may comprise a common adjustment member which is able, by employing different actuating means, to cause an adjustment in the same direction or an adjustment in the opposite direction.

Some embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic perspective view of an oscillator, Figure 2 is a longitudinal section through one practical constructional form of the oscillator according to Fig. 1, Figure 3 is a horizontal section through the oscillator of Fig. 2, Figure 4 is a diagrammatic view which shows the transmission employed with the oscillators according to Figs. 1 to 3, Figure 5 is an oscillator having a divided unbalanced member, the components of which are adjustable in the same and/or opposite directions, and Figure 6 is a diagrammatic perspective view of an oscillator, in which both unbalanced shafts have respective epicyclic gears.

Fig. 1 shows two unbalances shafts 1 and 2 which are arranged parallel to one another and on which are mounted weights 3 and 4 respectively. The shaft 1 is driven by a motor (not shown) by way of a driving belt 5 and a belt pulley 6 which is arranged thereon. The V-belt pulley 7 drives the annulus 9 through a toothed belt 8, the said annulus engaging planet wheels 11 with its internal teeth. Each plant wheel 11 is mounted on one of the three journals of a spider member 10, and engages with the external toothing of a sun wheel 12, which is mounted on the unbalanced shaft 2. The member 10 has a disc shaped part which is mounted on the unbalanced shaft 2 and whose circumference is formed as a gear wheel. The free end of a control rod 14 is formed as a rack and engages these gear teeth.The control rod 1 4 is guided in the plate 1 3 and is pretensioned by means of a spring 1 5.

In operation, the shaft 1 with the unbalance member or weight 3 is driven by the driving motor, which is not shown. The annulus 9 is driven by the shaft 1 via the belt 8 in such a manner that, when the member 10 is secured to the shaft 2, the sun wheel 1 2 and the shaft 2 run in synchronism with the belt pulley 7 and the unbalanced shaft 1.The use of the toothed belt 8 prevents the occurrence of "slip"; alternatively, instead of a toothed belt, it is possible to use a roller type chain, or the pulley 7 and the annulus 9 may be respectively provided with external teeth, which mesh with an interposed spur gear 1 6. If the control rod 1 4 is displaced longitudinally, the member 10 will be rotated about the axis of the unbalanced shaft 2, and the sun wheel 1 2 is given an additional rotation by displacement of the planet wheels 11, which rotation is effective as an alteration of the phase position of the unbalanced weight 4 with respect to that of the unbalanced weight 3.

By displacement of the control rod 14, the unbalanced weight 4 can thus be displaced from the in phase position which is represented in Fig. 1 to a sealing or lagging relationship with respect to the unbalanced weight 3.

One example of a practical form of such an oscillator mechanism is shown in longitudinal section in Fig. 2 and as a horizontal section taken at the level of the unbalanced shafts in Fig. 3. The housing or casing is expediently divided in this horizontal plane.

Unbalanced shafts 1 and 2 are mounted on roller bearings in a housing and the ends of the shafts are fitted with closure caps, of which one is provided with a packing or seal through which the stub shaft can pass carrying the belt pulley 6. The unbalanced weights are connected to the respective unbalanced shafts by a key and keyway 1 8 and the sun wheel is connected to the unbalanced shaft 2 by a key and keyway arrangement 1 9. The annulus 9 is mounted on the unbalanced shaft by means of the roller bearing 20 and the sun wheel 1 2 is mounted thereon by means of the roller bearing 21.The control rod 1 4 is mounted in a projection on the housing 1 7 and is connected to an adjusting or setting lever 22, which permits the manual adjustment of the member 1 0. The torque which is exerted during operation on the member is in this case substantially taken up by the spring 15; a safeguard against any accidental displacement is offered by the frictional resistance provided in the adjustment means. Furthermore, it is possible to establish preferential positions by a gating system wimilar to that used in a gear shift.As a consequence, it is only necessary for the person operating the vibrator or shaker plate to swing the setting lever 22 from its middle position, which is shown in full lines and which corresponds to the stationary position, according to the required running direction and also running speed. The transmission ratios which exist with the arrangement according to Figs.

1 and 3 are represented by reference to Fig.

4. Since the two unbalanced or eccentric shafts are intended to run synchronously, i.e.

the belt pulley 7 is to rotate at the same speed of rotation as the sun wheel 12, the ratio of the diameters will be in accordance with the formula: d,/d2 = d4/d3 The planet gears do not enter into the transmission ratio, since they engage both with the internal of the annulus and on the sun wheel, and as a consequence do not alter the circumferential speeds of these two wheels.

However, the preferred arrangement of the invention not only permits the continuous alteration of the phase positions of two unbalanced or eccentric members, in order constantly to change over from one running direction to the stationary position and to the opposite running directions, but also permits the simplification of the reversing and pivoting of a vibrator plate equipped with the oscillator. In the arrangement of Fig. 5, at least one of the unbalanced or eccentric weights is divided into two component weights 4 and 4', which are of th same size and disposed axially following one another, which weights are respectively mounted separately by means of roller bearings 39 and 39' on the eccentric shaft 2, which in this case is fixed in the housing.

The oscillator of Fig. 5 is driven by way of belt pulley 6 which is arranged externally of the housing on the unbalanced shaft 1. This latter shaft not only carries the eccentric weights or members 3, but also two belt pulleys 7 and 7', which drive the annuli 9 and 9' of two epicyclic gears by way of toothed belts 8 and 8', each of which epicyclic gears is operative on one of the component weights 4 and 4', respectively. In order to reduce the loads on the bearings, the annuli 9 and 9' are mounted on lateral shoulders of the eccentric members 4 and 4', which at the same time carry the sun wheels 1 2 and 12'. The reference numerals which have already been used in Figs. 1 to 4 are also employed for corresponding parts in Fig.

5. The control rods 14 may in this case always be adjusted separately by setting levers 22 and 22'. For the normal running conditions, the setting levers 22 and 22' will be shifted by equal angles in the same direction. If the vibrator plate is to be reversed, then the setting levers 22 and 22' are oppositely actuated. In this way, one of the eccen tric weights 4 and 4' is adjusted with a lead with respect to the eccentric weight 3 and the other with a lag with respect thereto, and the result is thereby obtained that the resultant oscillations in two planes which are parallel to one another and normal to the eccentric shafts differ from one another and the required reversing operation is assisted by different oscillations which cause moments.A simplification of the operation is provided when using one setting lever, the control rods 1 4 and 14' are moved in the same direction, so that the normal functions are capable of being set with this setting lever, while a second setting lever causes an additional and opposite movement of the two control rods 14 and a sconsequence initiates rotational movements of the vibrator plate. In addition, however, the possibility also exsists of providing an adjustment means 40 with a setting lever movable in two components, with which the movement in one component causes adjustments of the control rods in the same direction and a movement in the other component causes adjustments in the opposite direction.Correspondingly, the members 10 and 10' are also moved in the same or in opposite directions and corresponding displacements of the phase positions of the component members 4 and 4' are executed.

In theory, infinite phase adjustment can be achieved by rotating the spider member or an epicyclic gear. If it desired to provide considerable phase displacements, the stroke or travel of the control rods 1 4 and 14', respectively, can be suitably designed or the rotational movement can be caused by a worm engaging in an external toothing of the member 1 0. To reduce the number of rotations of the worm shaft required to cause the adjustment, a multi-thread worm, or spiral may be provided; an adjustment from the side of the gearing will certainly not be considered to be very desirable in most cases, but a spur gear would also be able to engage from the side in a tooth formation of a member 1 0. In the constructional example of Fig. 6, a rapidly effective adjustment through larger phase angles is achieved by symmetrical construction or design. The two eccentric shafts 1 and 2 comprising eccentric members 3 and 4 are respectively driven by way of epicyclic gears, and the common drive is provided by the fact that the belt pulley 6 driven from the motor via the belt 5 is arranged on a separate lay shaft 23 which drives the teeth of one of the annuli by means of a pinion 24. This annulus in its turn meshes directly with the second annulus 29.In this case also, the sun wheels 1 2 and 32 are directly connected to the eccentric shafts 1 and 2, respectively, and the planet wheels 11 and 31 are respectively arranged on a member or spider 10 or 30, which are provided with external toothing. A toothed section of a piston 25 engages in the teeth of the spider 10 and has one end guided in a cylinder 26 and the other end guided in a cylinder 27. A piston rod 35 engages in the cylinder 27 from the other side and has a toothed region which meshes with the teeth of the spider 30. Its opposite end is guided in a cylinder 34. The cylinders 26, 27 and 34 are filled with a fluid under pressure, the cylinder 26 being connected to the outlet 36 and the cylinder 34 to the outlet 37 of a hydraulic setting arrangement 28, which includes a piston 38 which is actuated by a handle.If the handle is shifted towards the left, fluid under pressure is displaced from the left hand piston chamber of the cylinder 28 and moves the piston member 25 towards the left, at the same time also displacing the piston 35 by way of the pressurising medium contined in the cylinder 27. At the same time the pressurising fluid displaced from the cylinder 34 flows to the outlet 37 and into that cylinder chamber of the adjustment arrangement 28 which is on the right hand side.

As a result the directly meshing and thus oppositely running annuli 9 and 29 cause the eccentric shafts 1 and 2 of Fig. 6 to be synchonously driven in opposite directions and the displacements in the same directions of the plungers 25 and 35 which are caused by a displacement of the piston 38 of the adjusting arrangement 28 also cause rotations in the same direction of the members 10 and 30, which in their turn cause phase displace ments in opposite directions of the eccentric members 3 and 4. A reliable locking of the adjusted position can easily be achieved in this connection, by providing one of the feed lines to the outlets 36 or 37 with a shut-off valve, which may for example be opened by a slight rotation of the toggle lever connected to the piston rod of the piston 38.Thus, before each adjustment, the toggle lever is slightly rotated, the required position of the members 10 and 30 is effected by advancing or retract ing the toggle lever and, after releasing the latter, the said lever is swung back under the action of a spring (not shown) against a stop member, and this closes the shut-off valve.

The invention is also capable of being modified in many different ways. Thus, the connecton between setting levers of adjustment ar rangements and the spiders of the epicyclic gear can be caused hydraulically or mechani cally, in which case, as regards the mechani cal system, linkages and/or Bowden cables, possibly with interposed levers, can be used, and also various combinations of mechanical and hydraulic elements are possible. In order to improve the controlling properties, the com ponent eccentric members 4 and 4' which are shown in Fig. 5 can be separated by a greater distance from one another.In this case in order to keep the shaft length within limits, the eccentric members 3 may also be divided, and the belt pulleys 7, in the same way as the epicyclic gears, are in each case positioned between the component eccentric members, in order to utilise the space between them. In this connection, the belt pulleys 7 and 7' can be replaced by a common belt pulley, and the toothed belt 8 driven from this latter jointly drives the annuli 9 and 9' which are connected to one another.

According to the invention, it is possible to dispense with the large and heavy housing required by known arrangements by arranging the bearings of the unbalanced shafts 1 and 2 on the vibrator plate itself, or on the section members which rinforce the said plate. It may then be necessary to weld short horizontal stays on the vibrator plate or on the reinforcing means thereof, which stays are able to receive the bearings. The entire oscillator then bears almost directly above the vibrator plate, thereby avoiding additional dead weights, so that an extremely compact structure is produced.If the shafts are driven through belts, and with the transmission of the rotational movement between the eccentric shafts by means of toothed belts, particular protective measures are not necessary in this case; it is thus sufficient for the respective bearings and the epicyclic gear or gears to be sealed off and for them to be covered by a simple sheet metal cover which prevents any access of dirt.

It has also proved to be advantageous in this respect for the member or spider not only to be mounted on the phase adjustable unbalanced shaft, but also on the support of the bearing of this said shaft or another fixed point, so that a plain bearing is sufficient for the mounting of the adjustable spider, or for the roller bearing employed to be only lightly loaded.

In the case of all constructional examples which have been indicated, there is provided the possibility of the phase displacement of unbalanced or eccentric bodies by the use of an epicyclic gearing which has a radial toothing, without any great expense being involved for the production thereof and without any complicated structure being necessary, and without there being any need for any appreciable additional space requirement.

Claims (18)

1. An oscillator having a mechanism including two rotating unbalanced members mounted on respective first and second parallel shafts which are rotatable synchronously in use in opposite directions with relatively adjustable phase positions wherein the shaft of at least one of the unbalanced members or weights is connected to a gear assembly including an annular gear having internal teeth which drive the unbalanced member via planet wheels and a sun wheel, and including a spider supporting the planet wheels which can be rotated by an adjustment means.

2. An oscillator mechanism according to claim 1, in which the sun wheel is mounted on the first said parallel shaft.

3. An oscillator according to claim 1 or 2, wherein the spider is mounted on one of the parallel shafts.

4. An oscillator mechanism according to claim 1 or 2, wherein the spider is fixed centrally in relation to the unbalanced shaft.

5. An oscillator mechanism according to any of claims 1 to 4, wherein the second unbalanced shaft and the annulus of the epicyclic gear operating the first unbalanced shaft are equipped with pulleys or sprocket wheels and are connected by means of a belt or chain.

6. An oscillator mechanism according to any of claims 1 to 4, wherein the second shaft and the annulus of the planetary gearing driving the first shaft are interconnected by means of an odd number of gear wheels.

7. An oscillator mechanism according to any of claims 1 to 6, wherein the spider includes an eccentrically provided knuckle pin to engage with an adjustment rod.

8. An oscillator mechanism according to any of claims 1 to 6, wherein the spider is provided with external teeth which engage a rack formed on an axially displaceable adjustment rod.

9. An oscillator mechanism according to claim 7 or claim 8 wherein the adjusting rod is displaceable by hydraulic cylinders.

10. An oscillator mechanism according to any one of claims 7 to 9, wherein the adjusting rod is biassed by a spring and is restrained by a friction member.

11. An oscillator mechanism according to any one of claims 1 to 10, wherein the spider is formed as a worm gear or helical gear and the adjustment means comprises an intermeshing worm or helical wheel respectively.

1 2. An oscillator mechanism according to any of claims 5 to 11, wherein the diameters (d, and d2) of the gear wheel sprocket wheel, or belt pulley of the second shaft and of the annulus have the same ratio as that of the diameters (d4 and d3) of the toother portion of the sun wheel to the internal toothing of the annulus.

1 3. An oscillator mechanism according to any preceding claim wherein an epicyclic gear train is provided for each gear and arranged before the unbalanced shafts, the spiders of the said gear trains being adjustable so as to act in opposite directions.

1 4. An oscillator mechanism according to any preceding claim, wherein one of the unbalanced members or weights is divided axially into two independently mounted component weights each of the components weights having associated therewith an epicyclic gear train driving it and having an adjustment means acting on its spider.

1 5. An oscillator mechanism according to claim 14, wherein the adjustment means in cludes two adjustment means, one of which adjusts the spiders in the same direction and the other of which adjusts them in opposite directions.

1 6. An oscillator mechanism according to any of claims 1 to 1 5 mounted in an open support or frame.

1 7. An oscillator mechanism according to any of claims 1 to 6, in which the support or frame includes a vibrator plate.

18. An oscillator mechanism substantially as herein described with reference to Figs. 1 to 4 or Fig. 5 or Fig. 6 of the accompanying drawings.