DK2963218T3

DK2963218T3 - LOCKING DEVICE IN A LOCK SEQUENCE CONTROL DEVICE FOR A TWO-FLY SWING DOOR SYSTEM

Info

Publication number: DK2963218T3
Application number: DK15164405.1T
Authority: DK
Inventors: Joachim Augenstein
Original assignee: Geze Gmbh
Priority date: 2014-06-30
Filing date: 2015-04-21
Publication date: 2017-10-02
Also published as: HK1218944A1; PL2963218T3; EP2963218B1; EP2963218A1; DE102014212570B4; DE102014212570A1; ES2642168T3; CN105220977B; CN105220977A

Description

BLOCKING DEVICE OF A LOCKING SEQUENCE CONTROLLING DEVICE OF A TWO-LEAF ROTATING DOOR ASSEMBLY

The invention relates to a device for regulating the closing sequence of a two-leaf revolving door assembly according to the preamble of claim 1. DE 10 2006 028 875 B3 discloses a device for regulating the closing sequence of a two-leaf revolving door assembly, which has a active leaf and a passive leaf. The active leaf and the passive leaf are each operatively connected to a drive shaft of a drive device. Furthermore, a blocking device is provided, by means of which the active leaf may be blocked or released according to the position of the passive leaf, wherein it comprises a coupling point for a mechanical transmission element. The blocking device acts on a movable component of the drive device of the active leaf by having a brake drum coupled to the movable component via a freewheel bearing. The brake drum is surrounded by a one-piece brake lining, which is spring-loaded against the brake drum. The pivoting of an expansion element releases the brake lining from the brake drum. EP 1 870 551 A2, which discloses the features of the preamble of claim 1, discloses a device for regulating the closing sequence of a two-leaf revolving door assembly which blocks or releases a active leaf as a function of the position of a passive leaf by being applied to a motor shaft of a drive motor of the drive device of the active leaf. The actuating device is designed as a tilting element and is moved by a transmission element. Overload protection is not integrated here.

The invention is based on the object of providing a reliable and self-adjusting blocking device for a closing sequence control device of a two-leaf revolving door assembly.

The object is achieved by the features of patent claim 1.

The subclaims form advantageous embodiments of the invention.

According to the invention, the blocking device has a first brake element which is designed as a brake cone and on which at least one brake segment of a rotatable and axially-displaceable pressure part acts, wherein a pressure spring presses the brake segment axially in the direction of the brake cone to block rotational movement of the motor shaft in the closing direction, wherein the mechanical transmission element moves the pressure part axially away from the brake cone against the force of the pressure spring, so that the at least one brake segment is lifted off the brake cone to release the rotational movement of the motor shaft in the closing direction. In this way, an extremely reliable construction is achieved, while the blocking device is self-adjusting to compensate for wear.

In embodiments of the blocking device according to the invention for a closing sequence control device of a two-leaf revolving door assembly, the brake cone includes the freewheel on the motor shaft and is attached accordingly to the motor shaft depending on the direction of rotation.

According to the invention, overload protection is triggered by a twisting of the pressure part under load, wherein a run-on web arranged on the pressure part runs onto a stationary fixed run-on ramp when a predetermined torque threshold value is reached, so that the at least one brake segment is lifted from the brake cone to release the rotational movement of the motor shaft in the closing direction.

The release torque of the overload protection may be adjusted by adjusting a biasing force of a release spring, which is in operative connection with the pressure part and a fixed stop web. In this way, the pressure part may be rotated counter to the force of the release spring. Due to the overload protection, damage to the revolving door assembly may be prevented in an advantageous manner.

In a further advantageous embodiment, the pressure part may be supported rotatably and axially-displaceably by means of a guide sleeve in a guide opening of a base part, wherein the coupling point for the mechanical transmission element is arranged at the bottom of the guide sleeve. The pressure spring may, for example, be designed as a helical compression spring which is supported at one end at the bottom of the guide sleeve and at the bottom of the guide opening through which the mechanical transmission element is guided, at the other end.

In a further advantageous embodiment, the pressure part may be embodied symmetrically with respect to the vertical axis and have two braking segments which are arranged opposite one another with each acting on an angular segment of the brake cone of less than 90°.

In a further advantageous embodiment, an electrical brake device may be provided with a solenoid and a rotatable and axially-displaceable brake block which has at least one braking segment. In this case, the solenoid in the energized braking state presses the brake block axially against the force of a restoring spring in the direction of the brake cone by means of an actuating ram and block the motor shaft from rotating in the closing direction, so that the at least one brake segment is lifted off the brake cone to release the rotational movement of the motor shaft in the closing direction. Advantageously, this results in a modular blocking device with an electrical braking function. For example, a base part may be arranged on a connection flange mounted on the electric motor, via which the blocking device for the integrated closing sequence control (IS) and the electrical brake may be installed in a modular manner. On the conical friction disc mounted on the motor shaft and containing a sleeve freewheel for determining the braking direction, presses the integrated closing sequence control system (IS) either via the blocking device or the electric brake.

In a further advantageous embodiment, the brake block may be mounted rotatably and axially-displaceably on a rounded guide surface of the base part via a rounded recess, wherein the actuating ram may act on an actuation plate of the brake block.

In a further advantageous embodiment, the brake block may be embodied symmetrically with respect to the vertical axis and comprise two brake segments which are arranged opposite one another and respectively act on an angular segment of the brake cone of less than 90°. The brake block and the pressure part may be arranged in such a way that the brake segments of the pressure part and the brake segments of the brake block alternate at the circumference of the brake cone. This allows a particularly compact design of the blocking device with an integrated electric brake.

In a further advantageous embodiment, the overload protection may be triggered by a twisting of the brake block under load, wherein the brake block acts on the pressure part and twists this when a predetermined torque threshold value is reached. In this case, the twisted pressure part may actuate a microswitch which interrupts a current supply to the solenoid, so that the restoring spring may move the brake block axially away from the brake cone in the non-energized state of the solenoid, so that the at least one brake segment of the brake block is lifted from the brake cone to release the motor shaft in the closing direction.

Embodiments of the invention advantageously result in a modularly-constructed blocking device with an electrical brake. In this case, the overload torque may be adjusted both for the electrical brake and for the blocking device of the integrated closing sequence control (IS). In this way, damage may be prevented or safe operation of the door assembly may be made possible. The blocking device of the integrated closing sequence control system (IS) may be lifted or released either by the mechanical transmission element or by the run-on ramps. The electrical brake is also supported by the integrated closing sequence control system (IS), thereby utilizing its torque setting to cancel the braking effect via the microswitches in the event of overload.

Exemplary embodiments of the invention are explained in more detail below with reference to drawings. In the drawings, the same reference numerals designate components or elements which perform the same or analogous functions.

Fig. 1 shows a two-leaf revolving door assembly with a closing sequence control device in a front view;

Fig. 2 shows a perspective view of a first exemplary embodiment of a blocking device according to the invention for the closing sequence control device of a two-leaf revolving door assembly from Fig. 1;

Fig. 3 shows a plan view of the first exemplary embodiment of a blocking device according to the invention from Fig. 2;

Fig. 4 shows a front view of the first exemplary embodiment of a blocking device according to the invention from Fig. 2 or 3;

Fig. 5 shows a sectional view of the first exemplary embodiment of a blocking device according to the invention along the cutting line V-V in Fig. 4;

Fig. 6 shows a perspective view of a second exemplary embodiment of a blocking device according to the invention for the closing sequence control device of a two-leaf revolving door assembly from Fig. 1;

Fig. 7 shows a plan view of the second exemplary embodiment of a blocking device according to the invention from Fig. 6;

Fig. 8 shows a front view of the second exemplary embodiment of a blocking device according to the invention from Fig. 6 or 7; and

Fig. 9 shows a sectional view of the second exemplary embodiment of a blocking device according to the invention along section line IX-IX in Fig. 8.

Fig. 1 shows a two-leaf revolving door assembly 1 with a active leaf 2 and a passive leaf 3, which are mounted on a stationary door frame 5 by means of hinge-type fittings 4 enabling it to rotate about a respective vertical axis of rotation. The active leaf 2 and the passive leaf 3 are each operatively connected to a drive device 6, 7 in the form of revolving door drives, which are mounted in the upper horizontal region of the door frame 5 in the illustrated exemplary embodiment.

Output members, each configured as output shafts 10, 11 with vertical axes of rotation, are mounted in the housings 8, 9 of the drive devices 6, 7, wherein the ends of the output shafts 10, 11 respectively protrude from the housings 8, 9. Force transmission elements in the form of sliding arms 12, 13, are mounted in a rotationally-fixed manner at the lower end, i.e. at the ends of the drive shafts 10, 11 facing the active leaf 2 or the passive leaf 3. The other ends of the sliding arms 12, 13 are respectively guided in a linearly-displaceable manner by means of a respective slider in a sliding rail 14, 15 mounted in the region of the upper horizontal edge of the active leaf 2 or of the passive leaf 3. A rotary movement of the output shaft 10, 11 of the drive device 6, 7 causes the sliding arms 12, 13 to pivot and move the active leaf 2 or the passive leaf 3 via the slider guided in the slide rail 14.

The drive devices 6, 7 each have a control device (not shown here), which controls the movement sequence of the drive devices 6, 7, e.g. as a function of sensor signals and/or manual switching operations. The control device may comprise a memory device in which the parameters required for operating the drive devices 6, 7 may be stored in a non-volatile manner. A device for regulating the closing sequence has the effect that when the passive leaf 3 is not in its closed position, the active leaf 2 may not be moved in the closing direction, but instead remains in the at least partially open position until the passive leaf 3 reaches its closed position. For this purpose, a blocking device 20, 20A is provided in the drive device 6 of the active leaf, which is described in more detail below with reference to Fig. 2 to 9. The drive device 6 has an electrical drive motor 16, the motor shaft 17 of which protrudes from the drive motor 16 on both sides. On one side, the drive motor 16 may interact with a transmission (not shown). The transmission interacts with the output shaft 10 of the drive device 6 so that a rotary movement of the motor shaft 17 causes a rotary movement of the output shaft 10, To this end, a closing spring is provided, which is prestressed by the drive motor 16, which is actuated in the opening direction. When the energization of the drive motor 16 ends, the closing spring then relaxes again and causes a rotational movement of the output shaft 10 of the drive device 2 in the closing direction.

In principle, positioning of the output shaft 10 of the drive device 6 in the case of the at least partly open position of the connected leaf is only possible by the drive motor 16, wherein the drive motor 16 remains permanently energized after reaching this position of the output shaft 10, and thus generates a counterforce which compensates the force of the closing spring.

However, this would result in a higher current consumption and possibly also a disturbing noise emission by the stationary permanently energized drive motor 16,

In order to avoid this disadvantage, a blocking device 20, 20A, which interacts with the motor shaft 17 of the drive motor 16, is provided on the end face of the drive motor 16. As is further shown in Fig. 2 to 9, the illustrated embodiments of the blocking device 20, 20A according to the invention for a closing control device of a two-leaf revolving door assembly 1 block or release the active leaf 2 as a function of the position of the passive leaf 3, wherein it comprises a coupling point 21 fora mechanical transmission element 18 and acts on the motor shaft 17 of the drive motor 16 of the drive device 6 of the active leaf 2 by having a first brake element 19 coupled to the motor shaft 17 via a freewheel bearing 19.1. According to the invention, the first brake element is designed as a brake cone 19, on which at least one brake segment 35, 36 of a rotatable and axially-displaceable pressure part 30 acts, and which is pressed axially in the direction of the brake cone 19 by a pressure spring 39 and a rotational movement of the motor shaft 17 in the closing direction. The mechanical transmission element 18 moves the pressure part 30 axially away from the brake cone 19 against the force of the pressure spring 39, so that the at least one brake segment 35,36 is lifted off the brake cone 19 to release the rotational movement of the motor shaft 17 in the closing direction.

The transmission element 18 (shown here only in sections), which may be embodied as a thrust member, for example a push rod or Bowden cable, is a component of the device for controlling the closing sequence like the blocking device 20, 20A, and extends to the passive leaf 3, in particular to a movably-coupled component of the drive device 7 of the passive leaf 3. In the illustrated position of the pressure part 30, the blocking device 20, 20A blocks the movement of the motor shaft 17. The reaching of the closed position of the passive leaf 3 leads to a displacement of the transmission element 18 and thus to an axial displacement of the pressure part 30, wherein the blocking device 20, 20A releases the movement of the motor shaft 17 and the active leaf 2 may then be closed.

Fig. 2 to 5 show a first exemplary embodiment of the blocking device 20, wherein only the drive motor 16 with the motor shaft 17 of the drive device 6 of the active leaf 2 is shown here for the sake of clarity. A connection flange 22, which carries the components of the blocking device 20, serves to connect the blocking device 20 to the drive motor 16. In the illustrated exemplary embodiment, the connection flange 22 comprises an L shape, wherein the connection flange 22 is connected to the drive motor 16 on a first leg. On a second leg, which is perpendicular to the first leg, the connection flange 22 has a base part 24 with a guide opening 25, in which the pressure part 30 is rotatably and axially-displaceably supported by a guide sleeve 38. The coupling point 21 for the mechanical transmission element 18 is arranged at the bottom of the guide sleeve 38. In the exemplary embodiment shown, the pressure spring 39 is designed as a helical compression spring and is supported, on the one hand, at the bottom of the guide sleeve 38 and, on the other, at the bottom of the guide opening 25, through which the mechanical transmission element 18 is guided. In addition, the pressure part 30 is designed symmetrically with respect to the main axis z and has two brake segments 35, 36 which are arranged opposite one another and respectively act on an angular segment of the brake cone 19 of less than 90°. The brake segments 35, 36 have beveled braking surfaces facing the brake cone 19 and are connected to the guide sleeve 38 by means of angled connection elements.

As may be seen in Fig. 2 to 5, an overload protection may be triggered by a twisting of the pressure part 30 under load, wherein a run-on web 37 arranged on the pressure part 30 runs onto a stationary run-on ramp 28 when a predetermined torque threshold value is reached, so that the at least one brake segment 35, 36 is lifted from the brake cone 19 to release the rotational movement of the motorshaft 17 in the closing direction. The run-on ramp 28 is formed on the first leg of the connection flange 22 and extends essentially perpendicularly from the first leg of the connection flange 22. In order to ensure that the overload protection is effective in both directions of rotation of the pressure part 30, the pressure part 30 has two run-on webs 37, which respectively interact with a run-on ramp 28 arranged on the first leg of the connection flange 22. A release torque of the overload protection may be adjusted by adjusting the prestressing of a release spring 34, which is arranged in a receiving bore 32 of an adjusting block 31. The release spring 34 is operatively connected to the connection flange 22 by means of an adjusting screw 33 and the adjusting block 31 in operative connection with the pressure part 30 and a stationary fixed stop web 26, which protrudes essentially perpendicularly from the first leg of the connection flange 22. The prestressing of the release spring 34 is adjustable via the adjusting screw 33 which is screwed into an internal thread of the receiving bore. The pressure part 30 is displaceable against the force of the release spring 34. In order for the overload protection to be effective in both directions of rotation, the pressure part 30 has two adjusting blocks 31 with corresponding receiving bores, release springs 34 and adjusting screws 33, wherein the stop web 22 is arranged between the two adjusting blocks 31 so that the release springs 34 are each arranged on a side surface of the stop web 22.

Fig. 6 to 9 show a second exemplary embodiment of the blocking device 20A, wherein only the drive motor 16 with the motor shaft 17 of the drive device 6 of the active leaf 2 is shown here for the sake of clarity. In addition to the components already described with reference to Fig. 2 to 5, the blocking device 20A in the illustrated second exemplary embodiment has an electrical brake device 40 with a solenoid 41 and a rotatable and axially-displaceable brake block 44, which comprises at least one braking segment 45, 46. The electrical brake device 40 is provided for the purpose of positioning the active leaf 2 when the integrated closing control system (IS) releases a movement of the active leaf 2 due to the position of the passive leaf 3, i.e. when the mechanical transmission element 18 moves the pressure part 30 axially away from the brake cone 19 against the force of the pressure spring 39 into the release position of the pressure part 30, so that the at least one brake segment 35, 36 is lifted off the brake cone 19 and the rotational movement of the motor shaft 17 is released in the closing direction. In the energized braking state, the solenoid 41 presses the brake block 44 axially in the direction of the brake cone 19 against the force of a restoring spring 43 via an actuating ram 42, and blocks a rotational movement of the motor shaft 17 in the closing direction. When the solenoid 41 is not energized, the restoring spring 43 moves the brake block 44 away from the brake cone 19 so that the at least one brake segment 45, 46 is lifted off the brake cone 19 to release the rotational movement of the motor shaft 17 in the closing direction.

Analogously to the first exemplary embodiment, the connection flange 22 carries the components of the blocking device 20A and serves to connect the blocking device 20A to the drive motor 16. In the illustrated second exemplary embodiment, the connection flange 22 has an L shape, wherein the first leg is connected to the drive motor 16, and the second leg comprises the base part 24 with the guide opening 25 in which the pressure part 30 is rotatably and axially-displaceably arranged via a guide sleeve 38. As may be seen in Fig.6 to 9, in addition to the pressure part 30, the brake block 44 is supported rotatably and axially-displaceably on a rounded guide surface 24.1 of the base part 24 by means of a rounded recess 44.1, wherein the actuating ram 42 is mounted on an actuation plate 47 of the brake blocks 44. The actuating plate 47 is supported on a flattening of the base part 24 and is arranged in the z direction above the recess 44.1, so that the brake block 44 may execute the axial sliding movement. The solenoid 41 with the actuating ram 42 and the restoring spring 43 is arranged on a flattened upper side of the base part 24. The brake block 44 is also designed symmetrically with respect to the main axis z and has two brake segments 45, 46, which are arranged opposite one another and which have beveled braking surfaces facing the brake cone 19. The braking surfaces each act on an angular segment of the brake cone 19 of less than 90°. As may be further seen in Fig, 6 to 9, the brake block 44 and the pressure part 30 are arranged in such a way that the brake segments 35, 36 of the pressure part 30 and the brake segments 45, 46 of the brake block 44 alternate on the circumference of the brake cone 19.

As is further apparent from Fig. 6 to 9, the electrical brake device 40 uses the overload protection of the pressure part 30. This means that the overload protection may be triggered by a rotation of the brake block 44 under load, wherein the brake block 44 acts on the pressure part 30 and twists this when a predetermined torque threshold value is reached. The twisted pressure part 30 actuates a microswitch 48, 49, which interrupts a current supply to the solenoid 41 so that the restoring spring 43 moves the brake block 44 axially away from the brake cone 19 in the non-energized state of the solenoid 41, so that the at least one braking segment 45,46 moves the brake block 44 away from the brake cone 19 and releases the rotary movement of the motor shaft 17 in the closing direction. To ensure that the overload protection is also effective in both directions of rotation in the second exemplary embodiment of the blocking device 20A, the pressure part 30 also has two adjusting blocks 31 with corresponding receiving bores, release springs 34 and adjustment screws 33, wherein the stop web 22 is arranged between the two adjusting blocks 31 so that the release springs 34 may each be supported on a side face of the stop web 22. In addition, two microswitches 48, 49 are arranged on the pressure part 30, the actuating elements of which are triggered in the direction of the stop web 22 by a corresponding rotational movement.

The second exemplary embodiment provides a combined, modular blocking device 20A with an electrical brake device 40 for a closing-sequence control device of a two-leaf revolving door assembly 1, which is distinguished by the overload torque for both the electric brake device 40 and the integrated closing sequence control system (IS) being adjustable thus preventing damage or being operationally reliable.

The pressure part 30 of the integrated closing sequence control (IS) and the electrical brake device 40 are modularly mounted on the connection flange 22, which is attached to the drive motor 16 on the base part 24. The pressure part 30 either presses the integrated closing sequence control system (IS) or the brake block 44 of the electric brake device 40 via the conical friction disk 19 supported on the motor shaft 17 and containing the sleeve freewheel 19.1, to determine the braking direction. The integrated closing sequence control system (IS) may be lifted or released by the mechanical transmission element 18 or by the run-on ramps 28, respectively. The brake block 44 of the electric brake device 40 is also supported on the pressure part 30 of the integrated sequence control system (IS) and thus uses its torque setting to cancel the braking effect in the event of an overload via the microswitches 48, 49.

List of reference numerals 1 Revolving door assembly 31 Adjusting block 32 Receiving 2 Active leaf bore 3 Passive leaf 33 Adjusting screw 4 Fitting 35,36 Brake segment 5 Door frame 37 Run-on web 6 Drive device 38 Guide sleeve 7 Drive device 39 Compression spring 8 Housing 40 Electrical brake device 9 Housing 41 Solenoid 10 Outputshaft 42 Actuating ram 11 Output shaft 43 Restoring spring 12 Sliding arm 44 Brake block 13 Sliding arm 44.1 Recess 14 Slide rail 45,46 Brake segment 15 Slide rail 47 Actuating plate 16 Drive motor 48,49 Microswitches 17 Motor shaft 18 Transmission element 19 Brake cone 19.1 Freewheel 20,20A Blocking device 21 Coupling point 22 Connection flange 24.1 Guide surface 25 Guide opening 26 Stop web 28 Run-on ramp 30 Pressure part

Claims

LOCKING DEVICE IN A LOCK SEQUENCE CONTROL DEVICE FOR A TWO-FLY SWING DOOR SYSTEM

A locking device (20, 20A) for a closing sequence control device for a two-wing pivot door system (1) having a transverse mobile wing (2) and a subordinate fixed wing (3) each connected to a drive shaft (10) , 11) in a drive (6, 7) wherein the blocking device (20, 20A) blocks or releases the mobile wing (2) depending on the position of the fixed wing (3), having a switching point (21) for a mechanical transmission element ( 18) and operates on a motor shaft (17) of a drive motor (16) in the mobile device (2) drive device (6), said blocking device having a first brake element (19) coupled to the motor shaft (17) by of a freewheel bearing (19.1) the blocking device (20, 20A), a press member (30) and a press spring (39), the first brake element being designed as a brake cone (19), on which at least one brake element (35, 36) of the rotatable and axially displaceable press members (30) act which press member, in press springs ns (39) locking state, is pressed axially in the direction of the brake cone (19) and the blocker rotary movement of the motor shaft (17) in the closing direction, where the mechanical transmission element (18), in the released position, moves the axial portion (30) axially away from the brake cone ( 19) against the force of the compression spring (39) such that the at least one brake segment (35, 36) lifts away from the brake cone (19) and releases the rotational movement of the motor shaft (17) in the closing direction, characterized in that the blocking device (20, 20A) has a an overload protector with an inlet tab (37) and a stationary inlet ramp (28), which overload protector can be triggered by the inlet tab (37) disposed on the press member (30) running against the stationary inlet ramp (28) when the preset torque threshold is such that the at least one brake element (35, 36) lifts away from the brake cone (19) and releases the rotational movement of the motor shaft (17) in close keretningen.

Locking device according to claim 1, characterized in that the release torque of the overload protection means can be adjusted by setting a biasing for a release spring (34), wherein the release spring (34) is operatively connected to the press part (30) and a stationary stop tab (26), where the press part (30) can be rotated against the force of the release spring (34).

Locking device according to one of the preceding claims, characterized in that the pressing part (30) is rotatably and axially displaceably mounted in a guide opening (25) in a base part (24) by means of a guide sleeve (38), wherein the coupling point (21) for the mechanical transmission element (18) is arranged on the bottom stool sleeve (38).

Locking device according to claim 3, characterized in that the compression spring (39) is in the form of a helical compression spring which is supported on the foot of the guide sleeve (38) at one end and on the bottom stool opening (25) at the other end. mechanical transmission element (18) is passed through said bottom stool opening.

Blocking device according to one of the preceding claims, characterized in that the pressing part (30) is designed symmetrically with respect to the vertical axis (z) and has two brake segments (35, 36) which are arranged opposite to each other and each act on a angular segment of the brake cone (19) less than 90 °.

Blocking device according to one of the preceding claims, characterized in that an electric brake device (40) is provided with a lifting magnet (41) and a rotatable and axially displaceable brake block (44) having at least one brake segment (45, 46) wherein the lifting segment (41), in the power-assisted braking condition, urges the brake block (44) axially in the direction of the brake cone (19) against the force of the return spring (43) by means of an actuating pressure rod (42) and blocks a rotational movement of the motor shaft (17) in the closing direction. and wherein the return spring (43) moves the brake block (44) axially away from the brake cone (19) in the non-energized state of the lifting magnet (41) so that at least one brake segment (45, 46) lifts away from the brake cone (19) and releases the rotational movement of the motor shaft (17) in the closing direction.

Blocking device according to claim 6, characterized in that the brake block (44) is mounted rotatably and axially displaceable on a rounded guide surface (24.1) of the base part (24) by means of a rounded recess (44.1), wherein the actuating pressure rod (42) acts on an actuating plate (47) of the brake block (44).

Locking device according to claim 6 or 7, characterized in that the brake block (44) is designed symmetrically with respect to the vertical axis (z) and has two brake segments (45, 46) which are arranged opposite to each other angular segment of the brake cone (19) less than 90 °.

Locking device according to claim 8, characterized in that the brake block (44) and the pressing part (30) are arranged such that the brake segments (35, 36) and the brake blocks (45, 46) of the pressing part (30) alternate over the brake cone ( 19) perimeter.

Blocking device according to one of the preceding claims 6 to 9, characterized in that the overload protection means can be released by rotating the brake block (44) under load of the brake block (44) acting on the pressing part (30) and rotating said pressing part when a a preset torque threshold is reached where the rotated press member (30) triggers a microswitch (48, 49) which interrupts a power supply to the holding magnet (41) so that the return spring (43) moves the brake block (44) axially away from the brake cone (19). the non-energized state of the holding magnet (41) so that at least one brake segment (45, 46) of the brake block (44) lifts away from the brake cone (19) and releases the rotational movement of the motor shaft (17) in the closing direction.