Patent ID: 12188491

DETAILED DESCRIPTION

All the figures show at least parts of a failsafe drive which is denoted overall by1.

The failsafe drive1has an output shaft3and a driving shaft4. A planetary gear mechanism24is provided between a support shaft2and the driving shaft4, which planetary gear mechanism24converts a drive torque which acts on the driving shaft4, and transmits it to the support shaft2and further to the output shaft3.

An actuating drive (shown inFIGS.10and11) is coupled to the driving shaft4via a coupling means (a feather key here), in order to drive the support shaft2and, furthermore, the output shaft3during normal operation. The failsafe drive1serves to actuate the output shaft3in the case of a power failure, and to move an armature or a valve which is connected to the output shaft3into a defined position, preferably into a closed position.

In the example, the failsafe drive1therefore forms a failsafe unit which can be retrofitted as a module to an actuating drive42. The actuating drive42is shown inFIGS.11and12and is connected to the driving shaft4of the failsafe drive1. In the case of further exemplary embodiments, the failsafe drive and the actuating drive are of integrated configuration with one another.

The failsafe drive1has a counter-element5(in the form of an output disc9here) which is connected at least indirectly to the output shaft3of the failsafe drive1.

The sectional illustration fromFIG.1illustrates that the failsafe drive1has a drive energy store6which comprises fourteen restoring elements in the form of cup springs7. Each of the cup springs7has a non-linear spring characteristic curve.

Furthermore, the failsafe drive1has a cam disc8which interacts with the abovementioned counter-element5, namely the output disc9. The cam disc8is arranged axially displaceably on the support shaft2. The cam disc8and the counter-element5are configured for the common conversion of an axial movement of the cup springs7into a rotational movement of the output shaft3of the failsafe drive1. In the exemplary embodiment which is shown, the axial movement of the cup springs7is an axial relieving movement of the cup springs7.

The cam disc8can be displaced axially along the support shaft2by way of the axial relieving movement of the cup springs7of the drive energy store6, in order to actuate the output shaft9which is connected at least indirectly to the output shaft3, and in order thus to move the output shaft3into the position which is provided for emergencies, even if the coupled actuating drive no longer functions, for example on account of a power failure. In the case of another embodiment of the failsafe drive1, the kinematic reversal of the above-described functional principle which will be described in greater detail in the following text is realised. Here, the counter-element5is then loaded axially by way of the cup springs7, and is displaced axially and sets the cam disc8in rotation, in order to move the output shaft3of the failsafe drive1into the position which is provided for the emergency.

The cam disc8has three control cams10which are arranged distributed uniformly about its rotational axis. The control cams10in each case have a course which is adapted to the non-linear spring characteristic curve is of the cup springs7in such a way that, in the case of activation of the failsafe drive1, a constant output torque is produced.

As has already been mentioned above, the cam disc8is guided longitudinally displaceably on the support shaft2. To this end, the support shaft2has corresponding guide structures on its outer side in the form of grooves and strips. Corresponding counter-grooves and counter-strips are provided on the cam disc8of the failsafe drive1. The cam disc8is thus guided longitudinally displaceably on the support shaft2, but is connected fixedly to the latter for conjoint rotation.

Together with the output disc9, the axially displaceable cam disc8forms a type of cam mechanism, by way of which the axial movement, brought about by way of the cup springs7of the drive energy store6, of the cam disc8can be transmitted via the control cams10and output rollers11, which interact in each case with the control cams10, to the output disc9and can be converted into a rotational movement of the output disc9.

The output disc9has a total of three output rollers11which are arranged distributed uniformly at an angular spacing of 120° about the rotational axis of the output disc9. Therefore, the output disc9has a number of drive rollers11which corresponds to a number of control cams10of the cam disc8.

The output rollers11are arranged in a rotatably mounted manner on the output disc9, and serve to convert the axial movement of the cam disc8into a rotational movement of the output disc9. In the case of an axial displacement of the cam disc8, the output rollers11roll along the control cams and bring about a rotational movement of the output disc9relative to the cam disc8which is connected fixedly to the support shaft2for conjoint rotation. The relative rotation between the cam disc8and the output disc9is possible as a result of canceling of the locking action between the support shaft2and the output disc9. The locking action will be described further below.

Furthermore, the failsafe drive1has a position indicator12for its output disc9. The position indicator12can be seen in the perspective illustration of FIG.4. With the aid of a curved rack25which is connected fixedly to the output disc9, the movement of the output disc9is transmitted to a second rack27via a transmission shaft26which has two pinions. The second rack27is connected to an indicator element28. The indicator element28can be moved into a viewing window29of the housing30by way of the movement of the output disc9, as a result of which the position of the output disc9can be read off from the outside.

The counter-element5of the failsafe drive1(that is to say, the output disc9here) is coupled at least indirectly to a movement damper13. In the movement damper13is shown inFIG.5, for example.

The movement damper13comprises a liquid chamber14which is filled with liquid, for example with oil, and at least one displacer element15which can be moved therein. The displacer element15is coupled to the support shaft2and, as a result, is connected at least indirectly to the counter-element5, that is to say the output disc9.

A degree of damping of the movement damper13can be set. The setting of the degree of damping can take place with the aid of its total of two flow regulators16and17which can be seen in the partially sectioned illustrations ofFIGS.6and7.

With the aid of the two flow regulators16and17, furthermore, the movement damper13is configured to provide different degrees of damping along an adjusting travel of the displacer element15through the liquid chamber14. It is provided here that the degree of damping which is provided by the movement damper13is greater in the region of an end position of the displacer element15on its adjusting travel through the liquid chamber14than a degree of damping in a region of the adjusting travel of the displacer element15between the end positions.

FIGS.6and7illustrate that two outlet openings31and32are provided within the liquid chamber14, through which outlet openings31and32liquid which is displaced with the aid of the displacer element15can be fed to the two flow regulators16and17.

On its main path, the displacer element15displaces the liquid in such a way that it can exit from the liquid chamber14through the two outlet openings31and32and can be fed to the two flow regulators16and17. As soon as the displacer element15passes the outlet opening31for the main path, the liquid which is displaced by way of the spacer element15can still flow out of the liquid chamber14only via the outlet opening32for the end position and can be fed to the flow regulator17for the end position. This leads to a degree of damping which is increased in comparison, with the result that the failsafe drive1, the actuating drive42and the machine part or fitting which is to be actuated by way of the actuating drive42are projected reliably against jolt-like loads when the output shaft3is moved into its end position.

The outlet openings31and32are connected via corresponding channels to the flow regulators16and17. Via a return channel33, the oil which is displaced out of the liquid chamber14on one side through the outlet openings31and32is fed to the liquid chamber14again.

FIG.4illustrates a locking apparatus18of the failsafe drive1. With the aid of the locking apparatus18, the cup springs7of the drive energy store6can be held in a tensioned state. This takes place by virtue of the fact that the locking apparatus18fixes, in particular rotationally fixes, the output disc9relative to the support shaft2and relative to the cam disc8, as has already been indicated above.

For this purpose, the locking apparatus18has a locking means19which is held close to a locking position by way of a restoring means20, by way of a restoring spring here. In this position, the locking means19does not yet connect the output disc9to the support shaft2. Furthermore, the locking apparatus18also comprises a clamping magnet21, by means of which the locking means19can be moved into its locking position and can be held counter to the restoring force of the restoring means20.

The locking means19is a latching lever which is connected via a toggle lever to the restoring means20and, in its locking position, engages into a corresponding latching recess34on the drive disc9and thus connects the output shaft9to the support shaft2fixedly for conjoint rotation. The latching apparatus has a latching carrier35which is connected fixedly to the support shaft2for conjoint rotation.

In the case of a power failure or in the case of emergency triggering, that is to say when the clamping magnet21is no longer activated or is currentless, the locking means19is no longer held in its locking position. The locking means19is moved on the output disc9by way of the torque which acts on the output disc. The fixed connection for conjoint rotation which the locking apparatus18provides between the output disc9and the support shaft2is canceled.

As a result of the cancellation of the fixed connection for conjoint rotation, the output shaft9can be rotated relative to the cam disc8. The drive energy store6with its stacked cup springs7thus becomes active and displaces the cam disc8axially on the support shaft2and in the process brings about a rotation of the output disc9, by way of which rotation the output shaft3and ultimately a machine part and/or a fitting which is connected to this output shaft3can be moved into the setpoint position which is provided for the case of an emergency. In the case of renewed activation of the clamping magnet21, the restoring means20assists it being possible for the locking means19to be moved into its locking position again.

The failsafe drive1has a test stop22. The test stop22can be seen inFIG.10and can be moved out of the non-use position into a use position. The use position, into which the test stop22can be moved, lies between two end positions of the output disc9, one end position of the output disc9being assigned to a tensioned position, and a second end position being assigned to a relieved position of the plurality of cup springs7of the drive energy store6of the failsafe drive4. A latch bolt which moves out of its starting position which is shown inFIG.10into its use position serves as test stop22.

If the test stop22is moved electromechanically into its use position, the function of the failsafe drive1can be checked, without the output shaft3being moved completely into its position which is provided for the case of an emergency. It thus becomes possible that the drive energy which is stored in the drive energy store6does not have to be discharged completely when the failsafe drive1is to be triggered for test purposes.

An electromechanical actuator36which can likewise be seen inFIG.10is provided for the actuation of the test stop22. The actuator36moves the test stop22into its use position, where it limits a rotary angular range, within which the output disc9can be rotated.

The failsafe drive1has a total of two limit position switches23in the form of in each case one microswitch. The limit position switches23are shown inFIGS.8and9, for example. The limit position switches23are mounted in a holder39in a sprung manner by means of a suspension means38, and are arranged in the housing30of the failsafe drive1. The limit position switches23are assigned to the counter-element5of the failsafe drive1. When the counter-element5reaches its end position, it makes contact with one of the limit position switches23by way of one of its two stops40. The stops40are mounted rotatably on the counter-element5, in order to make flat contact of the stops40against the limit position switches23which are assigned to them possible. As a result of the sprung mounting of the limit position switches23, the limit position switches23are protected against damage when the counter-element5(here, the output disc9) of the failsafe drive4loads the limit position switches23. Each limit position switch23is assigned a setting screw41. With the aid of the setting screws41, the positions of the holders39and therefore also the positions of the limit position switches23can be changed.

FIGS.11and12show the combination of the actuating drive42with the failsafe drive1. The actuating drive42has a drive motor43. The drive motor43is connected to an output shaft45of the actuating drive42. The output shaft45is connected to the driving shaft4of the failsafe drive1for the transmission of torque by means of a worm gear mechanism47. In this way, the output disc9of the failsafe drive1is also connected at least indirectly to the output shaft45of the actuating drive42.

It is possible for the output shaft45to be fixed. In the exemplary embodiment which is shown, the fixing of the output shaft45takes place via the abovementioned worm gear mechanism47which is a self-locking gear mechanism. It is prevented in this way that the drive motor43of the actuating drive42is rotated by way of the activated failsafe drive1. The fixing of the drive motor43ultimately leads to the support shaft2of the failsafe drive1being held fixedly by way of the carrier shaft2of the drive motor43for conjoint rotation when the drive motor43is currentless.

The actuating drive42has an electrical connector44. The actuating drive42can also be actuated manually via a handwheel46as required.

The invention is concerned with improvements in the technical field of actuating drives. To this end, inter alia, a failsafe drive4for an actuating drive1is proposed, which failsafe drive4has a drive energy store6which comprises at least one cup spring7and/or one cam disc8for the conversion of an axial drive movement of a restoring element into a rotational drive movement.

LIST OF REFERENCE NUMERALS

1Failsafe drive2Support shaft3Output shaft4Driving shaft5Counter-element6Drive energy store7Cup spring8Cam disc9Drive disc10Control cam11Output roller12Position indicator13Movement damper14Liquid chamber15Displacer element16Flow regulator for the main path17Flow regulator for the end position18Locking apparatus19Locking means20Restoring means21Clamping magnet22Test stop23Limit position switch24Planetary gear mechanism25First rack on926Transmission shaft27Second rack28Indicator element29Viewing window30Housing of131Outlet opening for the main path32Outlet opening for the end position33Return channel34Latching recess35Latching carrier36Electromechanical actuator37Guide means on238Suspension means for2339Holder for2340Stop on5/941Setting screw for2342Actuating drive43Drive motor44Electrical connection of4245Output shaft of4246Handwheel47Worm gear mechanism