EP2036105B1 - Actuator for actuating a safety switch - Google Patents

Description

The invention relates to an actuator for actuating a safety switch with a fastening element, an actuating element and provided for connecting the fastening element with the actuating element connection arrangement. The invention further relates to a safety switch with such an actuator.

Safety switches are usually used to forcibly turn on or off a power supply. The fields of application of safety switches are numerous. In industrial as well as in the private sector application scenarios, such as a protective door, a protective flap, a protective fence or similar arrangements with a safety switch can be realized.

In the current state of the art, such safety switches have a basic design, also called housing, and a separate actuator. This two-part design is based on the way of using the safety switch. The separate actuator and housing are mounted on separate mechanical units to be merged for a particular operating condition. For example, the separate actuator could be mounted on a movable door, whereas the housing of the safety switch could be attached to a wall or door frame.

The basic design of the safety switch has a drive head and can be constructed in one or more parts. Furthermore, the switching contacts are arranged in the basic design. The drive head has one or more openings into which the actuator is introduced, for example, to close NC contacts.

In the safe system state, which is given when the danger zone is shielded by a protective device, the actuator is located within the drive head. If, for example, a protective door is opened on which the actuator is located, then this is pulled out of the drive head. This has the consequence that the system is switched off by the positive opening of the NC contact, or is transferred to a safe state. If the system can not be easily switched off or the associated risk can be eliminated, the safety switch can also be provided to block the protective door.

The targeted introduction of the actuator proves to be problematic in the mechanical actuation of the drive head by the actuator. The safe insertion of the actuator in the drive head must therefore be ensured under mechanical load and safely trigger despite any deviations from the intended insertion. This tolerance problem arises from the fact that the drive head and the separate actuator are attached to different carriers that allow a certain amount of play. This problem is usually exacerbated by wear of the safety switch, improper handling of the safety device or by inadequate installation already during commissioning. It can be assumed that normally the separate actuator has an unavoidable offset to the insertion opening of the drive head. When the actuator is inserted, therefore, the actuator of the insertion opening of the drive head must be able to align.

Another problem is the angular insertion of the actuator in the case of flap-like protective objects. This problem is due to the fact that, for example, protective flaps are not operated linearly, such as sliding doors. The movement of a protective flap corresponds to a partial rotational movement about an axis of rotation, which is usually determined by hinges. Consequently, the actuator must be under a certain angle to be set previously be inserted into the drive head. This ensures that the actuator is aligned with the same when it reaches an end position in the drive head.

Another problem is the flexible mounting of an actuator by means of rubber grommets. For example, actuators are often fastened by means of two screws on a mounting surface, the actuator plate is flexibly mounted on rubber grommets and thus to be able to compensate for tolerances between, for example, a protective door and a frame only to a very limited extent. Because the holes in the actuator plate are usually much larger than the screw heads of the mounting screws, such actuators must generally be mounted with large-sized lock washers. If the ratio of the lock washer to the actuator plate bore does not match (eg, the lock washer could be too small), the rubber grommets may be moved over the head of the screw, creating a safety hazard. Furthermore, it has a disadvantageous effect with such actuators that only with considerable effort can a desired preferred direction be pretensioned.

Out DE 295 16 230 U1 a radius actuator is known, which is mounted on a complex body. Due to its basic body, the possible tolerance compensation of the actuator is very limited. A lateral offset is not possible and also the base body has a high number of components.

The DE 101 16 054 A1 describes a device for actuating a safety switch with a fastener and a engageable with the safety switch key element. The key element is displaceable relative to the fastening element against the restoring effect of a force accumulator having a longitudinal axis from an initial position. The energy accumulator is axially biased in the device to an extent that the energy storage when the key element is displaced transversely to the longitudinal axis of the force accumulator, a restoring force sufficient for resetting the starting position is exerted on the key element.

From the DE 101 23 943 C1 shows an actuator for a safety switch, which is provided with at least one insertion opening for the actuator, with a fastened to a respect to its open or closed position to be monitored part holder having a foot-side extension, rotatably and tiltably, and slidably held Key carries and on the side facing the key comprises a front plate having an opening which allows movement of the extending with his foot-side extension through the opening key in the plane of the front panel. Furthermore, a spring is provided on the side facing away from the key of the front panel, wherein on the side facing away from the key side of the front panel with a foot-side extension movable, the opening covering disc is provided. The disc is stretched by means of the supported at the end of the foot-side extension spring against the front panel so that the key maintains a position occupied by rotation and displacement relative to the opening position.

The US 6,949,712 B1 describes an actuator with a connection arrangement of an actuating element and a fastening element, wherein the connecting arrangement provides a biasing element for connecting the fastening element with the actuating element.

The invention has for its object to provide a simple and universally applicable actuator that allows tolerance compensation in any direction.

This object is achieved in an actuator of the type mentioned above in that the connection arrangement at least a, biased by at least one biasing element elastic element, for connecting the fastener having the actuating element. The object is further achieved by a safety switch with the features specified in claim 11.

The actuator according to the invention for actuating a safety switch has a fastening element, an actuating element and a connection arrangement for connecting the fastening element to the actuating element. Furthermore, the connection arrangement has at least one elastic element, which is pretensioned by means of at least one pretensioning element, for connecting the fastening element to the actuating element. In this case, the biasing element assumes the task of biasing the elastic element between the fastening element and the actuating element. The biasing element and optionally also the elastic element are provided for alignment in the direction of actuation. In this case, the elastic element ensures an all-round flexible offset or bending of the connection arrangement. The rigidity required for the operation of the connection arrangement can be realized both by the biasing element, the elastic element or by both elements together.

In an advantageous embodiment, the actuating element is resiliently mounted on the fastening element via the elastic element. The prescribed for the safety switch positive opening is ensured here by the rigidity of the biasing element. Here, there is a clear division of tasks between the two elements, which is advantageous in the selection of the components.

In an advantageous embodiment, it is possible to bias the elastic element by means of the biasing element to train or pressure. As a result, the actuator is always in a defined position. Advantageously, the actuator can be laterally deflected, compressed, twisted, offset parallel and / or bent by the combination of these two elements. Such an established actuator can move freely in all axes and thus offers the greatest possible tolerance compensation.

Advantageously, the biasing member is fixedly connected to the actuating element and the fastening element, so that, for example, one-piece embodiment loads, such as shocks, shocks or the like, can be intercepted and canceling the actuator is avoided. Should the elastic element still break, for example due to high wear or high stress, the actuating element is still connected to the fastening element via the pretensioning element, so that misuse or malfunction can be ruled out.

In an advantageous embodiment, the biasing element is disposed within the elastic member. By this arrangement it is ensured that the force counteraction for expected direction of force is similar. At different directions of force action of the actuator reacts with the same counterforce. In addition, the structure of the connection arrangement is kept very simple, so that there is a cost savings due to the small number of components.

Advantageously, the elastic element and the biasing element is made in one piece, wherein the elastic properties of the one-piece design change radially, ie substantially perpendicular to the actuation direction. For example, it is conceivable that the material density of the connection arrangement decreases continuously or stepwise from the inside to the outside.

Advantageously, the actuator has a mechanism for presetting the actuating direction of the actuating element. Thus, it is possible, for example between connection assembly and actuator, or between the connection assembly and fastener to provide a mechanism for presetting, depending on the application accordingly can be adjusted. As a result, the actuator for any conceivable application is universal, virtually as a radius actuator or universal actuator, can be used. Optionally, it is possible to provide pre-set angles for a specific application at the factory so that the user is no longer able to change this angle.

In an advantageous embodiment, a certain angle of the actuating element or a specific actuating direction by a change in the position of the elastic element and the actuating element relative to each other is adjustable. An actuation direction can here be adjustable by the user, or factory preset. In order to avoid unnecessary material costs, use is made of the already existing elements (actuating element and elastic element) in order additionally to achieve an angular adjustment of the actuating element. This could for example be done by the points of application of the elastic element to the fastening element, the actuating element and / or on an actuator plate having the actuating element, be changed or moved.

Further advantageous embodiments and preferred developments of the invention can be taken from the description of the figures and / or the dependent claims.

In the following the invention will be described and explained in more detail with reference to the embodiments illustrated in the figures.

FIG 1

ein erstes Ausführungsbeispiel eines Betätigers mit einer Stahlseilvorspannung,

FIG 2

ein zweites Ausführungsbeispiel eines voreingestellten Betätigers,

FIG 3

ein drittes Ausführungsbeispiel eines winkelverstellbaren Betätigers in einer ersten Position,

FIG 4

ein viertes Ausführungsbeispiel eines winkelverstellbaren Betätigers in einer zweiten Position, und

FIG 5

ein fünftes Ausführungsbeispiel eines winkelverstellbaren Betätigers in einer dritten Position.

Show it:

FIG. 1

A first embodiment of an actuator with a Stahlseilvorspannung,

FIG. 2

A second embodiment of a preset actuator,

FIG. 3

A third embodiment of an angle-adjustable actuator in a first position,

FIG. 4

A fourth embodiment of an angle-adjustable actuator in a second position, and

FIG. 5

A fifth embodiment of an angle-adjustable actuator in a third position.

FIG. 1 shows a first embodiment of an actuator with a Stahlseilvorspannung. The actuator has an actuator tip 4 as an actuating element and as a fastening element designed as a base plate 1 fastener. The connection arrangement between said elements is realized by an elastic element, which is designed as a compression spring 2 and a biasing element, which is designed as a steel cable 3 realized.

The compression spring 2 and the steel cable 3 represent simple but inexpensive components that realize a connection arrangement that accomplishes a compensating movement in substantially all directions and also allows the greatest possible tolerance compensation. In addition, it is possible to absorb stresses caused by impacts or shocks.

Advantageously, the actuator has only one elastic element, namely the compression spring 2, which is the only element subject to high signs of wear. Even if the spring is broken due to high stress or high wear, the safety function when removing the actuator is not impaired. In addition, damage is immediately recognizable.

FIG. 2 shows a second embodiment of a preset actuator. As in the first embodiment, the actuator has a base plate 1, a compression spring 2, a Steel cable 3 and an actuator tip 4, wherein the actuator tip 4 is preset in the direction of actuation. This default is permanent in this embodiment, so factory preset. The user has no way to manipulate the actuator, which can be a misuse excluded.

Advantageously, an unnecessarily large force on the drive head mechanism of the switch can be avoided by the default setting of the actuator and also by its flexibility.

Depending on the application of the safety switch, it may also be advantageous to make the default between the executed as a base plate 1 fastener and the connection assembly 2, 3, wherein the default is fixed preset or is changeable by the user.

A user-selectable orientation of the actuator tip 4 can be realized, for example, via a screw locking mechanism.

FIG. 3 shows a third embodiment of an angle-adjustable actuator in a first position. Compared to the first two embodiments, the actuator of this embodiment has an actuator plate 5 between the actuator tip 4 and the connector assembly 2, 3, on which the actuator tip 4 is mounted remotely. The decentralized position is not mandatory here. A central, near-edge or similar positions can also be advantageous depending on the geometry favored by the respective application. By a certain choice of the points of attack of the compression spring 2 and / or the steel cable 3 on the actuator plate 5, an angle adjustment of the actuator tip 4 is adjustable, wherein the steel cable 3 and the compression spring for different angles occupy a different relative position to each other.

The steel cable 3 is mounted decentralized within the compression spring 2, wherein the actuator plate 5 inclines together with the actuator tip 4 in the direction which is predetermined by the shortest distance of the steel cable 3 with the compression spring 2.

FIG. 4 shows a fourth embodiment of an angle-adjustable actuator in a second position. As already stated for the preceding exemplary embodiments, this exemplary actuator can also be used as an actuator preset for a specific actuating direction.

However, this second position occupied by the actuator could also represent a starting position for an actuator whose actuation direction setting can be adjusted variably by the user, for example, by the user FIG. 3 changed attack points are changed. Thus, the third, fourth and following fifth embodiments would be combined in a kind of universal actuator, which is application-related for various actuators.

The embodiments three, four and five could be combined into one, when the relative position of the compression spring 2 to the steel cable 3 is made variable and the actuation directions of the FIGS. 3 to 5 can be realized by a change of attitude. In the case of this type of universal radius actuator, for example, this could be achieved on the one hand by a steel cable mounted on at least one disk whose position can be changed by means of the disk. Advantageously, this disc is rotatable. In addition, the compression spring 2 can be made to change settings by, for example, on the base plate 1 and / or on the actuator plate provided for spring receiving recesses, such as grooves, in particular annular grooves are arranged, wherein the respective groove a new point of attack or another actuator direction Are defined. FIG. 5 shows a fifth embodiment of an angle-adjustable actuator in a third position. The remarks to 3 and FIG. 4 are applicable accordingly.

In summary, the invention relates to an actuator for actuating a safety switch with a fastening element, an actuating element and a connection arrangement for connecting said elements. A technical teaching is proposed which proposes a universally applicable and cost-effective actuator. For this purpose, the connection arrangement is realized with at least one elastic element, which is biased by means of at least one biasing element. In particular, by the inside bearing of the biasing element within the elastic element results in a very simple and robust construction of the connection arrangement.

Claims (11)

1. Actuator for actuating a safety switch, said actuator having a fixing element (1), an actuating element (4) and a connection arrangement (2, 3) provided for connecting the fixing element (1) to the actuating element (4), wherein the connection arrangement (2, 3) has at least one resilient element (2) which is pretensioned by means of at least one pretensioning element (3) for the purpose of connecting the fixing element (1) to the actuating element (4), characterised in that the pretensioning element (3) is a steel cable.
2. Actuator according to claim 1, wherein the resilient element (2) is provided to allow a flexible changing of the position of the actuating element (4) in relation to the fixing element (1) when force is applied.
3. Actuator according to one of claims 1 or 2, wherein the connection arrangement (2, 3) is provided for absorbing applications of force on the actuating element (4) along and/or perpendicularly with respect to an actuating direction.
4. Actuator according to one of the preceding claims, wherein the pretensioning element (3) is arranged inside the resilient element (2).
5. Actuator according to one of the preceding claims, wherein the resilient element (2) and the pretensioning element (3) are embodied as a single piece.
6. Actuator according to one of the preceding claims, wherein the resilient element (2) is a spring or a diaphragm.
7. Actuator according to one of the preceding claims, wherein the actuating element (4) and/or the fixing element (1) are also provided for the purpose of pretensioning the resilient element (2).
8. Actuator according to one of the preceding claims, wherein the actuator has a mechanism for setting the actuating direction of the actuating element (4).
9. Actuator according to one of the preceding claims, wherein the mechanism for setting the actuating direction of the actuating element (4) has different actuating directions in the case of different arrangements of the actuating element (4) relative to the resilient element (3).
10. Actuator according to one of the preceding claims, wherein the mechanism for setting the actuating direction of the actuating element (4) is disposed between actuating element (4) and connection arrangement (2, 3) or between the fixing element (1) and the connection arrangement (2, 3).
11. Safety switch having an actuator according to one of claims 1 to 10.

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