Safety element and coupling comprising several of these safety elements

Abstract

The invention relates to a safety element (5a) for a coupling (1) comprising two coupling elements (2, 3), wherein in a coupled state a torque can be transmitted between the two coupling elements (2, 3), and wherein by means of the safety element (5a) the two coupling elements (2, 3) can be switched into a disengaged state depending on the torque. The invention also relates to a coupling comprising at least one safety element according to the invention (5a).

Description

[0001] The invention relates to a safety element according to claim 1, which is provided for a clutch. It has the property of disengaging in a torque-dependent manner in the event of a malfunction due to overload. Furthermore, the invention relates to a clutch comprising several safety elements according to the invention, in particular a shaft coupling that can be switched in a torque-dependent manner using these safety elements.

[0002] The safety element is designed for a coupling comprising two coupling elements that can be regarded as coupling halves. In the case of a shaft coupling, a torque can be transmitted between the two coupling elements in the engaged state, wherein the two coupling elements can be automatically switched into the disengaged state by means of the safety element in a torque-dependent manner, i.e. when a defined torque is exceeded, with the proviso that the safety element comprises: a plunger which is displaceable in its axial direction by means of a provided bearing in order to provide the engaged state or the disengaged state of the coupling in the assembled state, a locking element which bears against the plunger, for example a ball, wherein the locking element preferably bears against a front end of the plunger, a spring device,by means of which a spring force can be transmitted into the plunger and further into the locking element, for example a disc spring assembly, wherein the plunger is provided with a shoulder element which protrudes in the radial direction on the plunger, preferably a circumferential annular shoulder element, wherein at least one transmission body is provided which is in contact with the shoulder element on the one hand and furthermore with at least one pressure body and cooperates therewith, wherein the transmission body is for example a rolling body and preferably the pressure body is designed as a circumferential annular pressure body, for which the pressure body has a deflection surface and the shoulder element comprises two functional surfaces, namely an inclined surface also pointing in the axial direction and a laterally arranged rest surface,wherein, in the engaged state of the coupling, the transmission body is in contact with the inclined surface of the shoulder element, transmitting the spring force, while in the disengaged state of the coupling (neutral), it rests against the lateral resting surface of the shoulder element. Further, in the assembled state, the plunger and the locking element are associated with a first of the two coupling elements of the coupling, and the other, second coupling element is associated with a locking region, e.g., a conical or dome-shaped opening, which locking region is complementary to the locking element. The locking region advantageously forms a component of the safety element or is associated with it.

[0003] Safety elements of this type, as well as couplings equipped with them, are required for heavy-duty machinery, for example, in mining, the construction industry, or in materials handling systems such as cranes, such as container cranes. For example, a container crane in a modern port terminal faces special requirements due to increasing automation.

[0004] Safety elements are also known which, if they are in the disengaged position and the coupling elements are separated after a malfunction, cannot automatically return to an engaged state. With this type of safety element, resetting must be achieved by manual operation, which is labor-intensive and always requires an operator on site. An example of this is US 2010 / 0224713 A1, which proposes a safety element and a coupling equipped with it. Each safety element is arranged on one coupling half and comprises a plunger which, when engaged, can transmit torque to the other coupling half by spring force in an advanced position. After a malfunction, the plungers and locking elements of all safety elements are pushed back into a position in which no further spring force can be transmitted to the plunger.The transmission of force from the spring mechanism is interrupted or neutralized. To switch the clutch back to torque-transmitting operation, the transmission of spring force to the tappet must be restored and the neutralization removed. With the aforementioned state of the art, this switching can only be achieved by manual intervention, which can be achieved, for example, with a targeted hammer blow and requires operating personnel.

[0005] Furthermore, in DE 10 2019 110 297 B3, the applicant has proposed a safety element which has a self-resetting function so that after disengagement, the clutch can be re-engaged without having to manually intervene on each safety element.

[0006] The known safety elements are subject to wear. This wear is essentially made up of a wear component that occurs when the clutch is disengaged while the torque limit is exceeded, and a wear component that occurs when the clutch is restored to the engaged state. A certain amount of wear occurs both when the clutch is engaged with a targeted hammer blow, and when the safety element is designed to reengage automatically.

[0007] The invention is based on the object of proposing a safety element which has an improved service life and a coupling equipped therewith.

[0008] According to the invention, the object is achieved in that a means for reducing wear is provided at least in the contact area of ​​the transmission body and the tappet and / or a means for reducing wear is provided at least in the contact area of ​​the transmission body and at least one pressure body.

[0009] Furthermore, it is advisable for the components within the housing to be operated in the presence of a suitable lubricant.

[0010] The transmission element is advantageously designed as a rolling element or a sliding element, with the wear-reducing means being designed as a groove for the transmission element. When installed, the groove acts as a guide for the transmission element. It is particularly advantageous if the cross-sectional shape of the groove conforms to the cross-sectional shape of the transmission element. The groove thus forms a channel that defines the path for the movement of the transmission element. By conforming the groove cross-section to the cross-section of the transmission element, the surface pressure between the two components can be reduced, thereby increasing the load-bearing capacity of the safety element. This increases the service life of the safety element.

[0011] It is very expedient if the transmission body is designed as a rolling element, e.g., a ball. When installed, a rolling element has three contact points with adjacent components of the safety element: a first contact with the plunger, a second contact with the pressure body, and a third contact, directly or indirectly, with the housing. Advantageously, at least one of the three components—plunger, pressure body, housing—is provided with a groove for the transmission body. Preferably, two components are provided with a groove for the transmission body: the plunger and the axially movable pressure body. Furthermore, the third contact point assigned to the housing can also be provided with a groove for the transmission body.

[0012] Even if the transmission element is designed as a rolling element, it does not necessarily have to perform a purely rolling motion; instead, it may have sliding components with the tappet or pressure elements. This results in a combination of rolling and sliding.

[0013] The groove extends in a radial direction or the shape of the groove has a radial component. When assembled, the groove acts as a guide for the transmission body. Preferably, the three components mentioned (plunger, pressure body, housing) are rotationally symmetrical, and preferably a plurality of grooves are provided around the circumference of all three components, which extend with a radial component. The grooves of each component have spacings from one another that are congruent with the grooves and spacings of the other components. When installed, the grooves of the different components lie exactly opposite one another and form a common groove guide for a corresponding number of transmission bodies, wherein each common groove guide preferably accommodates one transmission body.

[0014] As an alternative means for reducing wear, it is expedient to provide the locking element at least partially made of a ceramic material and / or the locking area element at least partially made of a ceramic material. This alternative means for reducing wear can also be combined with the previously described means of grooves or groove guides or can be provided with a chromium coating, preferably a hard chromium layer.

[0015] As a further means for reducing wear, at least one pressure body and / or at least one transmission body and / or the tappet are at least partially made of a ceramic material or provided with a chromium coating, preferably a hard chromium layer. This alternative means for reducing wear can also be combined with one of the aforementioned means for reducing wear.

[0016] An additional benefit is seen when the rest surface of the shoulder element of the plunger is further developed into an action surface that has an inclination relative to the axial direction of the plunger, namely, it is inclined at an angle α relative to the axial direction of the plunger. This measure allows for self-resetting of the safety elements after a malfunction if they have been switched to a disengaged state after a torque exceedance.

[0017] A clutch disengagement performed for safety purposes can be used, thanks to the self-resetting effect of the proposed safety element, to return a clutch to an operational engaged state. With this proposal, no operator on site needs to manually manipulate the clutch or intervene in all of the clutch's safety elements.

[0018] The direction of the suggested inclination of the resting surface corresponds to the direction in which the inclined surface of the shoulder element is also inclined. A correct angle for the inclination of the resting surface is required for proper function.

[0019] According to this concept, safety elements are provided that are designed for different torques and / or graded according to different sizes. This results in type series. For each safety element in a series, a suitable angle for the inclination of the rest surface on the shoulder element of the plunger is defined. The angle can be determined empirically, for example, for each size or for each desired torque.

[0020] During operation of a clutch, both coupling elements rotate at a certain speed. If the torque to be transmitted increases at this speed and exceeds the capacity of the combined safety elements, they automatically disengage, i.e., their plungers are returned against the force of the spring device. In the returned position, the transmission element, which is preferably a ball, rests neutrally against the rest surface.

[0021] In the safety element of US 2010 / 0224713 A1 and DE 10 2019 110 297 B3, a rest surface is provided on the shoulder element of the plunger, which is arranged parallel to the axial direction of the plunger. At the same time, the force of the spring device also acts in a direction parallel to the axial direction of the plunger. The spring force generated by the spring device always presses against the pressure body, and this against the ball as the transmission body. However, a transmission of force from the ball to the plunger is neutralized when the ball rests on the rest surface, because the ball cannot further deflect the spring force into the plunger due to the lack of an inclination of the rest surface. The known parallel rest surface prevents a deflection of force from the transmission body to the plunger.

[0022] In contrast, the new solution proposed here changes the function of the rest surface in a measured way by arranging the rest surface at an acute angle slightly inclined to the axial direction of the tappet instead of an exactly parallel alignment. In this way, the spring force that reaches the transmission body (ball) can be redirected by the ball in a defined transmission ratio, which can be adjusted by means of the moderate inclination of the rest surface. By choosing a suitable inclination of the rest surface, it can be ensured that after disengagement due to exceeding a defined torque, re-engagement is only possible with a reduced restoring force in the axial direction for safety reasons; the speed difference between the two coupling elements must be sufficiently small so that the reduced restoring force is sufficient to allow engagement.

[0023] If a technical problem has led to an increased torque load, causing the clutch's safety elements to disengage as a precaution, the underlying technical problem should first be resolved before slowly restarting the clutch. During an initial slow rotation of one clutch element, a slight restoring force in the plunger, generated by the gear ratio of the inclined resting surface, is sufficient to advance the locking element (e.g., ball) back into the engagement area of ​​the other clutch element.

[0024] The gear ratio, due to the inclination of the rest surface, is specifically selected so that re-engagement of the locking element is only possible at a significantly reduced speed. To do this, the clutch is first brought to a standstill and, before being put back into operation, the cause of the torque excess is identified and eliminated. To put the clutch back into operation, each plunger can be moved back to its advanced position without the need for an operator on site. To do this, the clutch simply needs to be slowly rotated again. The movement must be slow enough that the spring force, which is low due to the gear ratio, is sufficient to move the plunger into its advanced, engaged position. The clutch can then transmit its full torque again, for which it is designed.

[0025] Advantageously, the angle α of the inclination of the resting surface of the shoulder element is in a range of 3° to 12°, preferably in a range of 5° to 10° and particularly preferably in a range of 7° to 8°.

[0026] Advantageously, a first axially movable pressure body and a second pressure body are provided, wherein the second pressure body is arranged fixedly relative to the housing.

[0027] Advantageously, both pressure bodies are directly or indirectly spring-loaded, wherein each of the two pressure bodies has an inclined deflection surface, wherein each of the deflection surfaces is in contact with the transmission body, and wherein at least the deflection surface of one of the two pressure bodies is arranged inclined at an acute angle to a radial plane.

[0028] The bearing of the plunger can advantageously be integrated into a housing, wherein the housing has a connecting means designed for easy mounting of the safety element to a coupling element. If the housing has a cylindrical shape, then the connecting means can be, for example, an external thread on the housing, which can be screwed into a complementary internal thread of the coupling element.

[0029] The housing is expediently provided with an adjustment means or a combined fastening and adjustment means by means of which its axial position relative to the supporting coupling element can be adjusted when assembled. For the proposed safety element, it is considered important to enable adjustability of the axial position of several components that are arranged in a row when assembled. The components in question are the plunger, the locking element, and the engagement area. They should be arranged with as little play as possible or with a defined small amount of play relative to one another. The plunger and the locking element are located in the housing, which is assigned to one coupling element, while the engagement area is assigned to the other coupling element. This results in certain positional tolerances between the aforementioned components in their axial direction, which can be compensated for by the adjustability of the housing.

[0030] The aforementioned measure is considered not only dependent on the solution to the underlying problem stated above, but also as an independent inventive solution to the differing technical problem arising from the positional tolerances of the aforementioned components. Therefore, based on the preamble of claim 1, a safety element is hereby proposed, which is additionally provided with the aforementioned adjustment means for the housing in order to adjust its axial position relative to the supporting coupling element and indirectly adjust the axial position of the components: plunger, locking element, and locking area relative to one another.

[0031] The aforementioned independent solution for the adjustability of the aforementioned components is supplemented by the latching area being designed as an exchangeable latching area element which has a fixed positioning aid, wherein the positioning aid interacts with a stop means of the respective coupling element in the assembled state.

[0032] Advantageously, in a coupling with a plurality of safety elements, each of the locking elements (e.g. ball) can be brought into contact with each of the engagement area elements without having to pay attention to an aligned position of the two coupling elements, because for example only one engagement area element would be suitably adjusted for each locking element.

[0033] Advantageously, a guide bush is assigned which, in the assembled state, serves to guide the plunger and / or to guide the locking element, wherein the guide bush is also assigned to the first coupling element concentrically to the plunger.

[0034] The guide bush can be assigned as a separate component or it can be assigned as an integral part of the safety element, for example assigned to a housing part of the housing safety element.

[0035] The housing can have a closure element as a housing part, wherein the closure element acts as a counter bearing for the spring device and / or acts as a guide for the plunger and / or the locking element.

[0036] The closure element expediently comprises a means by which its axial position relative to the housing can be adjusted. The closure element is simply provided with a guide bore for the plunger and has an edge with an external thread. The external thread can serve as a means of fastening. Furthermore, the external thread can form the aforementioned means for adjusting the axial position. The external thread of the closure element expediently interacts with a matching internal thread provided in the housing, preferably a fine thread. Furthermore, a securing element can be provided, e.g. an aluminum piece that is embedded in a blind bore arranged in the region of the external thread and transverse to it.The aluminum piece extends into the area of ​​the external thread and is only deformed when the external thread is screwed into the internal thread of the housing, achieving a stopping effect, similar to the embedded plastic of a self-locking hexagon nut DIN 985, which deforms during screwing and acts as a screw lock.

[0037] The spring device can comprise at least one disc spring, preferably a disc spring package consisting of several disc springs is provided.

[0038] For the tappet, it is further proposed that it be composed of at least one tappet shaft and a shoulder element connectable to it, in particular a shoulder ring. The shoulder ring can have a conical action surface, or the conical action surface can additionally be provided with radial grooves. A suitable connection between the tappet shaft and the shoulder ring establishes a defined, fixed relationship between the tappet shaft and the shoulder ring, particularly in the axial direction. The two-piece design has the advantage of allowing the shoulder ring to be replaced separately. It is subject to particular wear during operation and may need to be replaced at a time when the tappet shaft can still be used. In this case, the existing tappet shaft is simply fitted with a new shoulder ring.In addition, it is possible to subject the shoulder ring to a targeted treatment that improves its wear properties and to leave the tappet shaft untreated or to subject it to another suitable treatment.

[0039] The coupling comprises two coupling elements which can be rotated about an axis and which can be switched into a coupled state and a disengaged state, wherein in the coupled state a torque can be transmitted, wherein on one of the coupling elements at a defined diameter and concentric to the axis of rotation of the coupling element at least one safety element according to one of claims 1 to 18 (preferably axially or radially) is arranged and in the case of a plurality of arranged safety elements a defined distance between the safety elements is preferably provided, and wherein on the second coupling element at an identical diameter and concentric to its axis of rotation a corresponding number of latching area elements are arranged and at congruent distances as the safety elements.

[0040] A circumferential groove is provided on the second coupling element, which interacts with the locking elements of the safety elements when disengaged.

[0041] The invention is illustrated below by way of example in a drawing and described in detail with reference to several figures. They show: Fig. 1 a coupling provided with six safety elements according to the invention, Fig. 2 a partial sectional view of a safety element according to the prior art mounted on a coupling and shown in the engaged state, Fig. 3 a partial sectional view of the known security element of the Fig. 2 in a fictitious separated state of the clutch, Fig. 4 a partial sectional view of a first embodiment of the safety element according to the invention mounted on a coupling and shown in the coupled state, Fig. 5 a partial sectional view of the embodiment of the Fig. 4 in another section plane in the coupled state, Fig. 6 a partial sectional view of the embodiment of the Fig. 4 and Fig. 5 in a separated state of the clutch, Fig. 7 a partial sectional view of a second embodiment of the safety element according to the invention mounted on a coupling and shown in the coupled state, Fig. 8 a partial sectional view of the embodiment of the Fig. 7 in a separated state of the clutch, Fig. 9 a perspective view of an alternative plunger for a third embodiment of the security element according to the invention, Fig. 10 is a perspective view of an alternative movable pressure body for the third embodiment of the safety element, Fig. 11 is a perspective view of an alternative stationary pressure body for the third embodiment of the safety element, Fig. 12 a perspective view of another alternative plunger for another embodiment of the security element according to the invention.

[0042] In Fig. Figure 1 shows a clutch 1 according to the invention, which has two clutch elements 2 and 3 (clutch halves) that are movable relative to one another and can be switched depending on the torque. In the present example, the clutch elements 2 and 3 are rotatable about a rotational axis 4 of the clutch 1. Therefore, the clutch 1 is a shaft coupling. It is torsionally rigid and switchable. Switching is possible between an engaged and a disengaged state and occurs depending on the torque.

[0043] Coupling 1 is intended, for example, for drive trains of machines such as those used in mining, the construction industry, or in material handling systems such as cranes. In particular, it is intended for use in container cranes. Sudden overloads can occur in such machines, endangering machine components such as motors, gearboxes, etc. To protect these components, the proposed coupling 1 separates the power transmission between the two coupling elements 2 and 3, thus keeping overloads away from these machine components and protecting them. Coupling 1 can therefore be referred to as a safety coupling or overload coupling.

[0044] To enable clutch 1 to fulfill its torque-dependent safety function, it is equipped with six safety elements 5a according to the invention. Each safety element 5a has a specific torque transmission capacity. In the present example, the total torque transmittable by clutch 1 is based on six safety elements 5a, so that clutch 1 essentially has six times the transmission capacity of a single safety element 5a.

[0045] The safety elements 5a are subject to wear. Certain components of the safety element 5a that are critical to operational safety are typically inspected regularly and replaced if necessary.

[0046] In order to improve the service life of the safety element 5a according to the invention, they are provided with means for reducing wear, as follows below.

[0047] The coupling element 2 carries the six safety elements 5a. For this purpose, it is designed like a flange. The positions for the safety elements 5a are distributed on the coupling element 2 on a circle (pitch circle) that is coaxial with the rotational axis 4 of the coupling 1. Each safety element 5a is rotationally symmetrical and has a central axis 6a. It is positioned with the central axis 6a on the pitch circle of the coupling element 2. In the present example, the central axes 6a of the safety elements 5a are arranged parallel to the rotational axis 4 of the coupling 1 or the coupling element 2. Alternatively, safety elements 5a can also be arranged in a radial orientation on a coupling element, for example, to obtain a coupling acting in the axial direction.

[0048] The Fig. 2 and Fig. 3 show a safety element 5b, which is part of the prior art and is attached to a flange-like coupling element 2. The coupling element 2 has a mounting plane 7, which is orthogonal to the rotation axis 4, and the safety element 5b also has a defined mounting plane 8. In the mounted state shown, the mounting plane 8 of the safety element 5b is in contact with the mounting plane 7 of the coupling element 2. As a result, in this prior art, the relative position of the coupling element 2 and the safety element 5b is fixed in the axial direction. The safety element 5b comprises a plunger 9 in a housing 10, wherein a housing edge 10a defines the mounting plane 8 of the safety element 5b. The plunger 9 is indirectly spring-loaded and presses against a detent ball 11. The detent ball 11 is according to Fig. 2 is engaged in a locking area 12, which is arranged on the opposite coupling element 3 and is axially adjustable by means of an adjusting screw 13. The plunger 9 has a shaft on which a shoulder element 14 is provided circumferentially. The shoulder element 14 is in contact with balls as transmission bodies 15. In Fig. Figure 3 shows the disengaged state of the safety element 5b, in which a cylindrical rest surface 16, as part of the shoulder element 14, has contacted the transmission bodies 15. In this position, the transmission of a spring preload to the plunger 9 is neutralized. To switch from the disengaged state back to the engaged state, the plunger 9 must be advanced from the outside, thereby pushing the locking ball 11 back into the engagement area 12.

[0049] As an embodiment of the invention (without figure) a security element is proposed which has the spatial physical design according to the Fig. 2 and Fig. 3, wherein a means for reducing wear is additionally provided. The means for reducing wear comprises a transmission body made of a ceramic material. Another exemplary embodiment provides that at least one component is made at least partially of a ceramic material or is at least partially provided with a wear-reducing coating. The component in question is selected from the group of the following components: tappet, tappet shoulder element, movable pressure body, static pressure body, transmission body. A tappet shoulder element means a separate shoulder element that can be assembled with a separate tappet shaft to form a complete tappet.

[0050] Fig. 4 shows a first illustrated embodiment of the security element 5a according to the invention. For comparable features, the same reference numerals are used for the sake of simplicity as previously in the description.

[0051] Fig. Figure 4 shows in particular that the safety element 5a is mounted on a coupling element 2 in a different manner than in the prior art. The proposed safety element 5a comprises a rotationally symmetrical plunger 9, which presses with a front end 17 against a spherical locking element (locking ball 11), wherein the plunger 9 is arranged in a housing 10, which has a bearing for the plunger 9 and enables its displaceability in its axial direction. The internal structure in the housing 10 of the safety element 5a corresponds to the structure of the known safety element according to Fig. 2 and Fig. 3 at least largely corresponds. In contrast to this prior art, however, the safety element dispenses with a housing edge as a mounting plane for fixed positioning on the respective coupling element 2.

[0052] Instead, the housing 10 is provided with a fastening and adjustment means 18, by means of which its axial position relative to the supporting coupling element 2 can be adjusted. The housing 10 is arranged coaxially with the tappet 9 and around it and has two end faces 10b and 10c. The end faces 10b and 10c form a bearing which has bearing openings L1 and L2, respectively, which serve as guide bearings for the axial mobility of the tappet 9. A seal S1 and S2 is arranged in each of the bearing openings. The fastening and adjustment means 18 is simply an external thread 19, which is provided on the outside of a cylindrical side wall 20 of the housing 10. The external thread 19 is expediently designed as a fine thread. To match this, the coupling element 2 is provided with a complementary internal thread 21, into which the external thread 19 of the housing 10 can be screwed.The screw connection, consisting of the external thread 19 and the internal thread 21, has a dual function. It serves both assembly and fastening purposes, and the aforementioned axial adjustability. The axial position of the housing 10 determines the axial position of the plunger 9, which is arranged in a row with the locking ball 11 and in a row with the associated engagement area 12, which is arranged on the other coupling element 3. The appropriate screw-in depth for the housing 10 is determined during assembly. This ensures a play-free connection between the plunger 9 and the engagement ball 11, and subsequently a play-free connection between the engagement ball 11 and the engagement area 12.

[0053] In addition, the plunger 9 is indirectly subjected to a preload generated by a spring device 22 arranged in the housing 10. The spring device 22 comprises a disc spring assembly 23 which is arranged coaxially around the plunger 9.

[0054] Alternatively, the screw-in depth of the housing 10 can also be selected such that a slight play is provided between the plunger / locking ball / locking area during assembly, for example, to ensure zero play only once the machine has warmed up and reached its intended operating state. A certain amount of heat-induced expansion of the components involved can reduce or eliminate play to a defined extent. During assembly, the housing 10 can, for example, be screwed in with a defined torque, in order to then rotate the housing 10 back in the opposite direction by a defined angle, thus creating a defined play.

[0055] The final screw-in depth of the housing 10 in the coupling element 2 is suitably secured. A suitable means 24 is provided for securing, as in the example of Fig. 4 a threaded pin 25 arranged in a bore 26 of the coupling element 2. When screwed in, the threaded pin 25 presses radially against the external thread 19 of the housing 10, fixing its position relative to the coupling element 2. To protect the external thread 19, an intermediate piece 27 made of aluminum as a soft metal is provided in front of the tip of the threaded pin 25, which is pressed against the external thread 19 of the housing 10 without damaging it. The intermediate piece 27 is deformed, thereby achieving a stopping effect, similar to the plastic of a self-locking hexagon nut DIN 985, which is deformed during screwing in and counteracts the loosening of the screw connection.

[0056] The engagement areas 12 for the locking balls 11 of each safety element 5a are arranged on the other coupling element 3. In the present example, the engagement areas 12 are each designed as an exchangeable engagement area element 28. The engagement area element 28 has an external thread that is screwed into an internal thread of the coupling element 3. Each engagement area element 28 has an engagement recess 29, here a recess with a conical inner surface 30. Furthermore, each engagement area element has a fixed positioning aid, which in this example comprises a radially projecting collar 31. In the assembled state, the projecting collar 31 interacts with a radial surface of the coupling element 3, which serves as a stop means. The correct axial position is always defined for the engagement area element 28.This eliminates the need to bring the two coupling elements into a specific rotational position relative to each other before engaging, as was the case with the prior art. The proposed engagement area elements 28 are manufactured with such high quality and dimensional accuracy that the locking ball 11 of each safety element 5a of the coupling can interact with any mounted engagement area element 28. In this way, the proposed safety element 5a generally facilitates engagement.

[0057] The Fig. 5 and Fig. 6 show how Fig. 4, the first embodiment. However, it is shown in a different sectional plane. Fig. 5 the engaged state, while Fig. 6 shows the plunger 9 and the detent ball 11 in a retracted position, which they assume when the clutch is disengaged. The detent ball has retracted from the engagement area. In Fig. 6, the locking area element 28 is shown in simplified form aligned with the plunger and the locking ball. In practice, however, the locking area element 28 has already rotated further; during the further rotation, the locking recess 29 has pushed the locking ball 11 back into the Fig. 6 shown position. In this respect, Fig. 6 a simplified theoretical representation of the disengaged state, showing the engagement area (simplified) at an incorrect rotational position.

[0058] Furthermore, in the section plane of the Fig. 5 shows another threaded pin 32 in another pin hole 33 in the coupling element 2. The section according to Fig. 5 lies in a different cutting plane than the cut in Fig. 4. The threaded pin 32 has a conical tip. It is used to assemble and secure the position of a guide bushing 34, which has a V-shaped circumferential groove on its outer surface. The tip of the threaded pin 32 is screwed into the V-shaped groove and thus fixes the position of the guide bushing 34, which serves to guide the detent ball 11 as well as a front end 9a of the plunger 9. For this purpose, the guide bushing 34 is provided with a first cylindrical inner surface 35, which forms the guide for the detent ball 11. A second cylindrical inner surface 36 forms the guide for the front end 9a of the plunger 9. In this example, the detent ball 11 has a larger diameter than the front end 9a of the plunger 9. The two cylindrical inner surfaces 35 and 36 of the guide bushing 34 are adapted to the two aforementioned diameters.Between the cylindrical inner surfaces 35 and 36, the guide bush 34 has the conical inner surface 37, which serves as a stop to limit the movement of the locking ball 11.

[0059] The coupling element 2 has a larger diameter than the coupling element 3 and accommodates a shaft seal 38 (shaft seal) comprising a sealing lip 39 that rests against the coupling element 3. The shaft seal 38 is arranged in such a way that the ingress of dirt into the guide bushing 34 and the engagement area 12 is counteracted.

[0060] In the sectional view of the Fig. 5 shows two transmission balls 15, each in contact with a stationary pressure body, which is designed as a ring-shaped pressure ring 40. In addition, an axially movable pressure body is provided, designed as a movable pressure ring 41. Finally, the tappet 9 has a shoulder element 14, which is designed as a ring-shaped shoulder ring. The shoulder ring comprises two functional surfaces. A first functional surface 42 is an inclined surface, which is designed as a circumferential groove 42a. The groove is designed such that its cross-section adapts to the shape or radius of the transmission balls 15. A second functional surface 16a of the shoulder element 14 is formed by a cylindrical rest surface 16, which in the present example, as in the prior art, is arranged parallel to the axial direction of the tappet 9.

[0061] Furthermore, Fig. 5 shows the spring device 22, which comprises six disc springs that are assembled to form the disc spring assembly 23. In the coupled state shown, the disc spring assembly 23 is in a slightly preloaded state. On the end face 10c of the housing 10, a housing opening is provided with a closure element 43, which serves as a counterbearing for the disc spring assembly 23 and encompasses one of the bearing openings for the tappet, which is provided with the seal S2. The closure element 43 is designed to be able to adjust the preload of the disc spring assembly 23 or to remove preload. For this purpose, a cylindrical inner wall 44 of the housing 10 is provided with an internal thread 45, and the closure element 43 has a cooperating external thread 46. Thus, the closure element 43 can be screwed into the housing 10 and can be preloaded more or less strongly against the disc spring assembly 23, or it can be left unloaded.To secure the desired setting, the cylindrical surface of the locking element 43, which is provided with the external thread 46, is provided with a pocket, simply a radial blind bore 47, into which a soft material, e.g., an aluminum spacer 48, is embedded. The soft material has no threads, but comes into contact with the internal thread 45 of the housing 10 during assembly and is deformed in the process. The deformed spacer 48 serves to secure the set position of the locking element 43. The deformed spacer 48 achieves a stopping effect, similar to the embedded plastic of a self-locking hexagon nut DIN 985.

[0062] The spring force of the disc spring assembly 23 acts on the transmission ball 15 via two deflection components, namely the static pressure ring 40 and the movable pressure ring 41. The latter, in turn, deflect a component of the spring force into the annular shoulder element 14 of the plunger 9. The plunger 9 is thereby subjected to a force component that preloads it toward the engagement area 12.

[0063] In Fig. 6, which shows the safety element in a disengaged state of the coupling, the plunger 9 has retracted from the engagement area 12, causing the transmission balls 15 to be moved radially outward beyond the first functional surface 42. In this position, the transmission balls 15 rest against the second functional surface 16a, which is designed as a cylindrical rest surface 16. The spring force emanating from the disc spring assembly 23 is thus neutralized. Although the spring force presses against the movable pressure ring 41 and this against the transmission balls 15, the transmission balls 15 cannot introduce any force or movement into the rest surface 16, as a result of which the plunger 9 remains stationary. The functionality of the rest surface 16 therefore corresponds to the cylindrical rest surface identified as such in DE 10 2019 110 297 B3.The publication proposes switching the plunger 9 into the engaged state by providing a spring-operated external actuating lever. Reference is hereby made to this type of reset; it can be used with the present first embodiment according to the . Fig. 4 to 6. Alternatively, the ram 9 can be manually advanced by an operator to restore the engaged state. Manual actuation can be performed, for example, by striking the ram with a hammer.

[0064] As a means of reducing wear, the first embodiment shown is the Fig. 4 - 6 at least one component is at least partially made of a ceramic material or at least partially provided with a wear-reducing coating. The component is selected from the group of the following components: tappet, tappet shoulder element, movable pressure body, static pressure body, transmission body.

[0065] The Fig. 7 and Fig. 8 refer to a second illustrated embodiment of the safety element. It comprises a wear-reducing means comprising at least one component that is at least partially made of a ceramic material or at least partially provided with a wear-reducing coating. The component is selected from the group of the following components: plunger, plunger-shoulder element, movable pressure body, static pressure body, and transmission body.

[0066] Based on the Fig. 7 and Fig. Figure 8 illustrates another essential aspect of this embodiment of the invention, namely how the safety element 5a is designed to provide a simplified self-resetting capability. Fig. 7 and Fig. 8 differs from the embodiment of the Fig. 5 and Fig. 6 essentially by a modified plunger 9, whose second functional surface forms an action surface 49, which has an inclination relative to the axial direction of the plunger 9. In the present example, the action surface is inclined at an angle α of 7.5° relative to the axial direction of the plunger 9. In the example, the action surface 49 is arranged circumferentially. This results in a truncated cone-shaped shape of the action surface 49.

[0067] But first, Fig. 7 shows the engaged state of the safety element 5a. The purpose is to be able to restore the engaged state after a malfunction when the clutch 1 is disengaged, without having to carry out any external operation on the safety element 5a, in particular without requiring any action on site, for example by an operator.

[0068] In Fig. 8 shows the separated state of the clutch 1. The two clutch elements 2 and 3 are disengaged. As in Fig. 6 is also Fig. 8 is a simplified theoretical representation of the disengaged state of the safety element 5a. The engagement area 12 has pushed the locking ball 12 and the plunger back against the spring force, so that the locking ball 11 has retreated from the engagement area 12. The engagement area has rotated further, the locking ball 11 rests against a radial surface of the coupling element 3, and in this position can no longer transmit any torque to the coupling element 3.

[0069] In addition, the axial retraction of the plunger 9 causes the transmission balls in Fig. 8 has been pushed radially outward beyond the first functional surface 42. Now the transmission balls 15 rest against the second functional surface, ie, the action surface 49, which is inclined at an angle α of 7.5° relative to the central axis of the tappet.

[0070] In contrast to the prior art, in the disengaged state, the inclined action surface 49 immediately redirects movement to the transmission balls 15. The origin of the movement is the spring force due to the preload of the disc spring assembly 23, which presses the movable thrust ring 41 against the transmission balls 15. As a result, the transmission balls 15 are pressed radially inward and, via the inclined action surface 49, redirect a force component into the plunger 9, which advances it toward the engagement area 12.

[0071] Due to the flat inclination of the action surface 49, the spring force is translated. The translation is selected such that a defined limitation of the force component occurs, which advances the plunger 9 in the axial direction. The intention is to allow the engagement process of the detent balls 11 into the engagement areas 12 in a material-friendly manner. The force is dimensioned such that engagement is preferably only possible with a small speed difference. With a larger speed difference, a greater advancing force in the plunger 9 would be required for engagement. The invention aims to prevent the associated increased material wear by reducing the axial force that can be introduced into the plunger 9 for advancement and engagement.On the one hand, the low advancing axial force reduces wear immediately after a malfunction, when coupling elements 2 and 3 are still rotating and frictional contact occurs due to a speed difference, causing material wear. On the other hand, subsequent commissioning also takes place in a material-friendly manner.

[0072] In the first case, when clutch 1 has disengaged torque-dependently during full operation, clutch elements 2 and 3 are initially still rotating, whereby a certain speed difference can quickly develop. Then, detent balls 11 and engagement areas 12 overtake each other while moving at different speeds and maintaining a certain degree of frictional contact. This causes a certain amount of wear. However, because the tappets 9 and detent balls 11 are only subjected to a defined, low advancing axial force, wear can be kept to a minimum during this operating phase.

[0073] During re-commissioning, it is recommended that, starting from the standstill of both coupling elements 2 and 3, the driving coupling element 2 or 3 should only be allowed to start up again slowly in order to be able to use the defined low advancing force that arrives in the tappet 9 to press the locking balls 11 into engagement with the locking areas 12 on the coupling element 3. If the driving coupling element accelerates too much, the clutch cannot be re-engaged.

[0074] A third illustrated embodiment is shown below with reference to Fig. 9. This shows a perspective view of an alternative tappet, which is to be referred to as a grooved tappet 9a. Starting from the first illustrated embodiment of the Fig. 4-6, its plunger is further developed into the grooved plunger 9a. The grooved plunger 9a can replace the plunger 9 to obtain the third illustrated embodiment of the safety element 5a.

[0075] The design of the grooved tappet 9a dispenses with a "built-in" self-resetting function. The grooved tappet 9a has a cylindrical shaft and an annular shoulder element 14 (shoulder ring 14a). The shoulder ring 14a is provided with a cylindrical resting surface 16. In the disengaged state, the effect of the disc spring assembly 23 is neutralized. The shoulder ring 14a is provided with grooves 50, which, when mounted, serve as a guide for the transmission bodies 15. According to the proposal of Fig. 9, the groove design of the groove tappet 9a represents a means according to the invention for reducing wear.

[0076] The proposed grooves 50 begin on the inside of the circumferential, fillet-shaped surface of the shoulder ring 14a and extend radially outward. The grooves 50 continue in the axial direction at the cylindrical rest surface 16 of the shoulder ring 14a.

[0077] The functional surfaces are now formed by the groove surfaces. The grooves 50 have adapted cross-sections, which, like the raceways of a rolling bearing equipped with rolling elements, are adapted to the shape of the respective transmission bodies 15. As a result, the groove surfaces increase the contact area for the transmission bodies 15. In this way, the surface pressure is reduced, and this design serves as a wear-reducing means.

[0078] When the safety elements 5a are disengaged, their transmission balls 15a are located in the outer region of the groove 50, which is aligned parallel to the center axis of the grooved plunger 9a. The effect of the spring force of the disc spring assembly 23 is then neutralized. To switch the separated clutch 1 back on, the grooved plunger 9a can be actuated from the outside to advance it so that the transmission bodies 15 can move inward again. For switching, the grooved plunger 9a can be advanced manually by an operator, for example, by striking with a hammer. Alternatively, the external spring-operated mechanism with an actuating lever known from DE 10 2019 110 297 B3 can be provided to automate advancement into the engaged state.

[0079] A further advantage is achieved when the safety element 5a is switched between the engaged and disengaged states, which in the first embodiment may involve neighboring transmission balls 15a being able to change their distance from one another. In the disengaged state, the distance between the transmission balls 15a is greatest. Without lateral guidance by grooves 50, transmission balls 15a may, under certain circumstances and disadvantageously, move toward or away from one another in the circumferential direction. This can be avoided by guiding them through the proposed grooves 50 of the grooved tappet 9a.

[0080] Based on Fig. 10, a further measure is proposed which concerns a modified axially movable pressure body and contributes to a means of wear reduction. The movable pressure body can replace the movable pressure body 41 of the first illustrated embodiment, or it can be used, for example, in a safety element 5a in combination with the grooved tappet 9a. The axially movable pressure body is annularly designed as a pressure ring 41a and has wear-reducing radial grooves 51, the cross-section of which is also adapted to the shape of the transmission bodies 15, here transmission balls 15a. In the grooves 51, the surface pressure relative to the transmission body 15 is again reduced, thus providing the means of wear reduction.In order to be able to combine the pressure ring 41a with the grooved tappet 9a, the pressure ring has radial grooves 51 in a congruent arrangement, so that in pairs one groove 50 of the grooved tappet 9a and one groove 51 of the pressure ring can act as a common guide for the transmission body 15.

[0081] Based on Fig. 11, a further measure is proposed which concerns a modified static pressure body. The static pressure body can replace the static pressure body 40 of the first illustrated embodiment or it can be used in a safety element 5a in combination with the grooved tappet 9a according to Fig. 9 and or with the movable pressure ring 41a according to Fig. 10. The static pressure hull of the Fig. 11 is designed as a ring-shaped pressure ring 40a and has radial grooves 52, the cross-section of which is also adapted to the shape of the transmission bodies 15, here again the transmission balls 15a. For a combination with the grooved tappet 9a and / or with the pressure ring 41a of the Fig. 10, the thrust ring 40a also has the radial grooves 52 in a congruent arrangement. Thus, a groove 50 of the plunger and / or a groove 51 of the movable thrust ring can interact in pairs with a groove 52 of the static thrust ring 40a. This results in common guides for the transmission bodies 15.

[0082] Fig. Figure 12 shows a design of an alternative grooved plunger 9b, which can replace the plunger 9 of the first illustrated embodiment and then results in a further embodiment of the security element 5a according to the invention. The grooved plunger 9b has a cylindrical shaft and an annular shoulder element (shoulder ring 14b) with two functional surfaces based on those functional surfaces of the second embodiment according to the Fig. 7 and Fig. 8. Its plunger has a shoulder element with two functional surfaces. The first functional surface is an inclined surface formed as a circumferential groove 42a. The second functional surface is the action surface 49, which has an inclination relative to the axial direction (center axis) of the plunger 9. Just as in the second embodiment, a safety element 5a provided with the grooved plunger 9b has a self-resetting function. Due to the self-resetting, the grooved plunger 9b, when it has entered the disengaged state, is subjected to an axial force that advances it toward its position for the engaged state, as shown in Fig. 7.

[0083] According to Fig. 12, additional radial grooves 53 are provided, which extend over both functional surfaces, with the second functional surface being arranged in the area of ​​the action surface 49 (conical outer surface). Because only the grooves 53 interact with the transmission bodies 15, in the present example the groove surface of each groove 53 serves as a replacement for the truncated conical action surface 49. Advantageously, the grooves 53 have the same inclination as the conical outer surface, which in Fig. 7 forms the action surface 49. In the assembled state, the radial grooves 53 act in Fig. 12 as a guide for the respective transmission body 15, preferably a rolling element. In the present example, the proposed transmission balls 15a are provided as the transmission body. The cross-sections of the radial grooves 53 are adapted to the shape of the transmission balls 15a, like the raceways of a rolling bearing.

[0084] An important aspect of this embodiment is again to reduce the surface pressure between the transfer bodies 15 and the grooves 53 of the shoulder ring 14b. This is achieved by adapting the cross-sections of the radial grooves 53, as mentioned, to the cross-sections of the transfer bodies 15, such as the transfer balls 15a proposed here.

[0085] A further advantage is also apparent here when the safety element 5a is switched between the engaged and disengaged state. In the first embodiment, this can be accompanied by neighboring transmission balls 15a changing their distance from one another. Generally, in all embodiments, the distance between the transmission balls 15a is greatest in the disengaged state. Without lateral guidance by grooves 53, transmission balls 15a can, under certain circumstances and disadvantageously, move towards or away from one another in the circumferential direction. By means of guidance by the proposed radial grooves 53 of the Fig. 12 this can be avoided. List of reference symbols 1 clutch 2 coupling element 3 Coupling element 4 rotation axis 5a Security element 5b Security element 6a Central axis 7 mounting level 8 mounting level 9 plungers 9a Grooved tappet 9b Grooved tappet 10 housings 10a Housing edge 10b front side 10c Front side (with housing opening) 11 locking ball 12 Snap-in area 13 Adjusting screw 14 shoulder element 14a Shoulder ring 14b Shoulder ring 15 transfer bodies 15a Transmission ball 16 cyl. rest area 16a second functional area 17 Pin end (plunger) 18 Fastening and adjustment devices 19 external threads 20 cyl. side wall (housing) 21 internal thread 22 Spring device 23 Disc spring element 24 remedies 25 threaded pin 26 Hole 27 Intermediate piece 28 Snap-in area element 29 Snap-in recess 30 interior surface 31 protruding collar 32 threaded pin 33 pin hole 34 Guide bushing 35 cyl. inner surface 36 cyl. inner surface 37 conical inner surface 38 Shaft seal 39 Sealing lip 40 Pressure ring (stationary) 40a Pressure ring (stationary) 41 Pressure ring (movable) 41a Pressure ring (movable) 42 first functional area 42a cove 43 Closure element 44 cyl. inner wall 45 internal thread (housing 10) 46 external thread (closing element) 47 Blind hole 48 intermediate piece (aluminum) 49 Action area 50 groove 51 groove 52 grooves 53 groove L1 bearing opening L2 bearing opening S1 sealing ring S2 sealing ring QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2010 / 0224713 A1 [0004, 0021] DE 10 2019 110 297 B3 [0005, 0021, 0063, 0078]

Claims

[1] Safety element (5a) for a clutch (1) comprising two clutch elements (2, 3), wherein in a coupled state a torque can be transmitted between the two clutch elements (2, 3), and wherein by means of the safety element (5a) the two clutch elements (2, 3) can be switched into a disengaged state in a torque-dependent manner, with the proviso that the safety element (5a) comprises: - a tappet (9, 9a, 9b) which is displaceable in its axial direction by means of a provided bearing in order to provide the engaged state or the disengaged state of the clutch in the assembled state, - a locking element which rests on the plunger, - a spring device by means of which a spring force can be transmitted to the plunger (9, 9a, 9b) and further into the locking element, - wherein the plunger (9, 9a, 9b) is provided with a shoulder element (14) which protrudes in the radial direction on the plunger (9, 9a, 9b), - wherein at least one transmission body (15, 15a) is provided, which on the one hand is in contact with the shoulder element (14) and furthermore with at least one pressure body (40, 40a, 41, 41a) and cooperates therewith, - for which the pressure body (40, 40a, 41, 41a) has a deflection surface and the shoulder element (14) comprises two functional surfaces (16a, 42), namely an inclined surface (42a) also pointing in the axial direction and a laterally arranged rest surface (16), - wherein the transmission body (15, 15a) is in contact with the inclined surface of the shoulder element (42a) in the engaged state of the coupling (1) to transmit the spring force, while in the disengaged state of the coupling (1) it rests against the lateral rest surface (16) of the shoulder element, and with the further proviso that in the assembled state the tappet (9, 9a, 9b) and the locking element (11) are assigned to a first of the two coupling elements (2) of the coupling (1), and that the other second coupling element (3) is assigned a locking region (12) which is designed complementarily to the locking element (11), - characterized by that a means for reducing wear is provided at least in the contact area between the transmission body (15, 15a) and the tappet (9, 9a, 9b) and / or a means for reducing wear is provided at least in the contact area between the transmission body (15, 15a) and at least one pressure body (40, 40a, 41, 41a). [2] Security element (5a) according to claim 1, characterized by that the transmission body (15, 15a) is designed as a rolling body or sliding body, and that the means for reducing wear is designed as a groove (50, 51, 52, 53) for the transmission body (15, 15a). [3] Security element (5a) according to claim 2, characterized by that the groove (50, 51, 52, 53) extends in a radial direction or has a radial component which, in the mounted state, acts as a guide for the transmission body (15, 15a). [4] Security element (5a) according to one of claims 1 to 3, characterized by that as a means for reducing wear it is provided that the locking element (11) and / or the locking area element (28) is made at least partially from a ceramic material. [5] Security element (5a) according to one of claims 1 to 4, characterized bythat as a means for reducing wear it is provided that at least one pressure body (40, 40a, 41, 41a) and / or at least one transmission body (15, 15a) is at least partially and / or the tappet (9, 9a, 9b) is at least partially made of a ceramic material. [6] Security element (5a) according to one of claims 1 to 5, characterized by that the rest surface (16) of the shoulder element of the tappet (9, 9b) is further developed into an action surface (49) which has an inclination relative to the axial direction of the tappet (9, 9b), namely is inclined by an angle (α) with respect to the axial direction of the tappet (9, 9b). [7] Security element (5a) according to claim 6, characterized by that the angle (α) of the inclination of the action surface (49) of the shoulder element (14) is in a range of 3° to 12°, preferably in a range of 5° to 10° and particularly preferably in a range of 7° to 8°. [8] Security element (5a) according to one of claims 1 to 7, characterized by that a first axially movable pressure body (41, 41a) and a second pressure body (40, 40a) are provided, and that the second pressure body (40, 40a) is arranged fixedly relative to the housing (10). [9] Security element (5a) according to claim 8, characterized by that both pressure bodies (40, 40a, 41, 41a) are spring-loaded, that at least one of the two pressure bodies (40, 40a, 41, 41a) has an inclined deflection surface, that each of the deflection surfaces is in contact with the transmission body (15, 15a), and that at least the deflection surface of one of the two pressure bodies (40, 40a, 41, 41a) is arranged inclined at an angle to a radial plane. [10] Security element (5a) according to one of claims 1 to 9, characterized bythat the bearing (L1, L2) of the plunger (9, 9a, 9b) is integrated into the housing (10), and that the housing (10) has a fastening means (18) which is prepared for the purpose of simple mounting of the safety element (5a) on a coupling element (2). [11] Security element (5a) according to one of claims 1 to 10, characterized by that the housing (10) is provided with an adjusting means (18) by means of which, in the assembled state, its axial position relative to the supporting coupling element (2) can be adjusted. [12] Security element (5a) according to one of claims 1 to 11, characterized by that the latching area (12) is designed as an exchangeable latching area element (28) which has a fixed positioning aid (31), wherein the positioning aid interacts with a stop means of the relevant coupling element (3) in the mounted state. [13] Security element (5a) according to one of claims 1 to 12, characterized bythat a guide bush (34) is assigned which, in the assembled state, serves to guide the tappet (9, 9a, 9b) and / or to guide the locking element (11), wherein the guide bush (34) is also assigned to the first coupling element (2) concentrically to the tappet (9, 9a, 9b). [14] Security element (5a) according to claim 13, characterized by that the guide bush (34) is assigned as a separate component or is assigned as an integral part of the safety element (5a), for example is assigned to a housing part of the housing (10). [15] Security element (5a) according to one of claims 10 to 14, characterized by that the housing (10) has a closure element (43) as a housing part, that the closure element (43) acts as a counter bearing for the spring device (23) and / or acts as a guide for the plunger (9, 9a, 9b) and / or the locking element (11). [16] Security element (5a) according to claims 10 to 15, characterized bythat the closure element (43) comprises a means by means of which its axial position relative to the housing (10) can be adjusted. [17] Security element (5a) according to one of claims 1 to 16, characterized by that the spring device comprises at least one disc spring, preferably a disc spring package (23) consisting of several disc springs. [18] Security element (5a) according to one of claims 1 to 17, characterized by that the tappet (9, 9a, 9b) is composed of a tappet shaft and a shoulder element connectable thereto. [19] Coupling (1) comprising two coupling elements (2, 3) which are rotatable about an axis (4) and which can be switched into a coupled state and into a disengaged state, wherein a torque can be transmitted in the coupled state, wherein on one of the coupling elements (2, 3) on a defined diameter and concentrically to the axis of rotation (4) of the coupling element (2) a plurality of safety elements (5a) according to one of claims 1 to 18 are arranged and have a defined distance from one another, and wherein on the second coupling element (3) on an identical diameter and concentrically to its axis of rotation (4) a corresponding number of latching area elements (28) are arranged, namely at congruent distances as the safety elements (5a). [20] Coupling (1) according to claim 19, characterized bythat a circumferential groove is provided on the second coupling element (3) which, in the uncoupled state, interacts with the locking elements (11) of the safety elements (5a).

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