DE102015016253B4 - Belt tensioner coupling device - Google Patents

Abstract

Coupling device (11) for the belt shaft (22) of a belt tensioner system with a, a stationary support ring (12) opposite to a system axis (28) rotatable drive wheel (13) on which parallel to the system axis (28) offset a coupling pawl (16) pivotable is mounted, which is equipped at its front end (18) with a toothed profile (19) for driving into an outer toothing (20) on the belt shaft (22), wherein for reversing the toothing engagement (19-20) with a Umsteuer- and entrainment -Profil (27) for the clutch pawl (16) equipped control ring (25) is connected in a frictional engagement with a stationary locking ring (37), characterized in that for a pulse-like controlled clutch pawl (16) a catching device (30) is provided with a the coupling pawl (16) centrifugally oriented tentacle (32) and angularly offset with one of a catch ring (34) zentripetal projecting fishing hook (33), wherein the fan Gring (34) relative to the control ring (25) axially offset and, for peripheral release of the pulse-like controlled clutch pawl (16) from the catcher (30), temporarily with the retaining ring (12) is connected in a frictionally engaged manner.

Description

The invention relates to a coupling device for a belt tensioner system to be installed, especially in passenger vehicles.

From the DE 100 59 227 C1 It is known to equip a belt shaft for winding a seat belt on a front end torsionally rigid with an internally toothed ring gear. This takes coaxially a front end of a motor-driven drive shaft, on which a coupling bolt is arranged transversely displaceable. This shifts when turning the drive shaft to positive engagement of its teeth in the internal teeth of the belt shaft ring gear, so as to tighten the belt tensioned. With gearing between the coupling bolt and the belt shaft, the belt can be removed manually from the shaft.

In the DE 10 2014 009 038 A1 It is proposed to tension a safety belt in an emergency out of the regular operating condition by an electric motor. In order not to have to switch to return to normal operating state, the drive direction, a inertia switching control is used.

In more comfortable electric motor driven belt tensioner systems, the applied belt alternately undergoes a tightening and a release in the normal operation via periodic tooth engagement of a coupling device to the belt shaft. For this purpose, a coupling device according to the generic here DE 10 2011 119 343 A1 be provided.

Thereafter, a drive wheel is provided for tensioning of the belt, which is driven by a motor relative to a coaxial, in principle device to be mounted mounting ring and a correspondingly mounted blocking ring. Typically, a high-speed, low-voltage electric motor, usually via a torque-increasing reduction gear, rotates the drive wheel about the system axis of the clutch device. In drive-in direction of rotation, the drive wheel gets into a positive rotational connection to the belt shaft by means of a coupling pawl. This rotary connection is canceled again, and thereby released the belt shaft for removing the belt, as soon as and as long as the motor drive for the drive wheel is programmatically reversed in the opposite direction in the direction of rotation.

The belt shaft protrudes with its externally toothed front end at a certain radial distance coaxially into a hub opening of the drive wheel. The reversible rotational connection between the drive wheel and belt shaft via the mutual engagement of corresponding, rampen- or saw-shaped teeth on the belt shaft and the clutch pawl. For this purpose, the coupling pawl is articulated on the drive wheel eccentrically to the system axis about a shaft parallel to its axis between two drive wheel fixed stops pivotally.

The rotational direction-dependent pivotal movement of the coupling pawl for input or Aussteuern of the meshing engagement with the belt shaft resulting from a positive engagement of the clutch pawl in a concentric to the drive wheel control ring. The coaxial with the system axis is originally fixed non-positively under preferably radial static friction on the stationary blocking ring. Only by the coupling pawl has been pivoted against a stop on the drive wheel is released as a result of this positive support, the control ring from the previous static friction to the blocking ring and now rotated with sliding friction against the blocking ring in the current direction of rotation of the drive wheel.

Temporary standstill due to reversal of the direction of rotation of the drive wheel first puts the control ring back into the static friction to the stationary locking ring until the control ring has pivoted the clutch pawl on the re-rotating drive wheel against the other stop. Then a torque is transmitted from the drive wheel via the coupling pawl to the control ring, which releases it again from its static friction to the blocking ring and now rotates under sliding friction in the new, current direction of rotation of the drive wheel.

The positive engagement between the clutch pawl and the control ring thus has two phases of operation in this context: While the control ring is held in place by static friction on the stationary blocking ring, the clutch pawl supported against the control ring is pivoted by the rotating drive wheel until against a stop on the drive wheel. This support of the clutch pawl against the drive wheel leads, via the maintained engagement between the control ring and clutch pawl, the control ring to the transition from the static friction in the sliding friction against the blocking ring by the control ring is now taken from the drive wheel.

After this pre-publication is not provided, in addition, axially offset relative to the coupling device, to the belt shaft a z. B. attack pyrotechnic drive to cause an accident in an extremely fast winding and thus tightening of the belt under irreversible modulation of the clutch device; a re-entry to return to normal operation is then no longer possible after such a rush drive has become effective once.

The present invention is based on the technical problem of designing a generic coupling device such that it can functionally reliably continue with normal operation with alternating tensioning and releasing of the belt after the end of an emergency drive.

This object is achieved by the essential features specified in the main claim. If, during the driving direction of rotation of the drive wheel, so at Gurtwelle driven clutch teeth, such - especially pyrotechnic - rapid drive in action, the clutch pawl along the Sägezahnflankenneigung the teeth of the belt shaft is raised because it suddenly rotates faster than the drive wheel , The clutch pawl is out of gear engagement, and it is due to their eccentric linkage on the rotating drive wheel to this articulation around slightly bowed radially outwardly thrown.

To reliably exclude kinetic interference during such temporary, impulse-initiated rapid drive, which may occur, for example, during a rebound of the clutch pawl, a catching device for the clutch pawl is provided. This serves to lock the clutch pawl which is controlled via the tooth flanks. For this purpose, the coupling pawl in a direction of actuation, ie away from the hub opening of the drive wheel away pointing arm with, for example, an angled free front end. As a result of the violent, superimposed radial and tangential components of movement of the clutch pawl whose tentacle engages behind an angularly offset fishing hook, the centripetally protrudes from a concentric to the system axis catching ring. Thus, the pulse-initiated modulation of the clutch pawl is locked latching in the catcher. Their catching ring is, similar to the control ring in the blocking ring, frictionally arranged on or in the stationary retaining ring.

If, when the only very briefly pending urgent drive of the belt shaft, the drive wheel is driven in Einsteuer-direction of rotation, this lock the modulation remains in the catcher still exist, the clutch pawl is therefore not yet reinstated. Because of the drive wheel, as a result of the positive engagement of the clutch pawl, the control ring and this formschlüssig via a stop under maintained the same orientation of fishing arm and fishing hook of the catch ring rotated, each under sliding friction against the stationary blocking or retaining rings.

The arresting effect of the catching device is automatically reversible. Because with the next program controlled reversal of the drive wheel drive in the direction of rotation direction first, at temporary standstill due to the reversal of direction, both the catch ring and the control ring from the previous sliding friction in the static friction to each stationary mounting or blocking ring. Since the clutch pawl has already been and still is controlled since the moment of initiation, nothing changes for her as yet. But while the catching ring with its catch hook remains frictionally resting, the drive wheel and the clutch pawl is rotated with its catch arm in the direction of drive. While the clutch pawl remains disengaged, the catching device opens because the catching arm has rotated relative to the catching hook. Upon reaching a constructive angle between fishing hook and tentacle a stop is reached, over which the catching ring from then on - as the clutch pawl - is rotated by the drive wheel.

If now, after the pulse initiation has subsided, the drive wheel is reversed to Einsteuerung, the clutch pawl, by means of their intervention in the control ring, pivoted into the Einsteuerung; and the belt coupling device is back to normal.

Thus, the coupling device works reversibly even after a pulse application, without manual intervention requirements due to mere change of the drive direction of their drive wheel.

According to an advantageous development of the solution according to the invention, it is still ensured that the coupling pawl only and only turns on when the catching device is in operational readiness with respect to the angle between the tentacle and fishing hooks; and also in operational readiness, if the clutch pawl is to steer again. For this purpose, the catching ring except the catch hook with a blocking base and the clutch pawl except for the tentacle also equipped with a blocking arm. These positively cooperating blocking means ensure that the coupling pawl can only be pivoted on or swung out when the catching device is already or ready for operation with regard to the angle assumed between catching arm and catching hook.

Further developments and their alternatives to the solution according to the invention will become apparent from the other claims and, taking into account the advantages thereof, from the following description of a preferred, scaled as greatly enlarged but outlined limited to the functional essentials simplified Implementation example of the invention. In the drawing shows:

1 the coupling device of the drive wheel without cover in axial view, namely

1a controlled and

1b Driven,

2 the output clutch device without consideration of the belt shaft in the axial cross-section along the indication II-II in 1a and

3 in interrupted axial cross section, the control catcher in operative position.

The invention reversibly latching coupling device 11 has a stationary, but not rigid but device-mounted under rotation angle game to be mounted retaining ring 12 concentric on a drive wheel 13 on. Under a cover 14 ( 2 ) is by means of paraxial from the drive wheel 13 worn pillar 15 concentric to the system axis 28 on rotation frictional also an equally stationary blocking ring 37 clamped.

At a pillar 15.1 or on a separate stub shaft is on the drive wheel 13 a clutch pawl 16 in the plane parallel to the drive wheel 13 pivoted. The clutch pawl 16 runs in this implementation example in principle as a one-armed lever angled or bent around a partial circumference of the hub opening 17 in the drive wheel 13 around. At the free forehead area 18 , the linkage 15.1 opposite, is a gearing 19 the clutch pawl 16 with a ramp or sawtooth profile to the hub opening 17 oriented.

A, also rampen or sawtooth shaped, sheathing 20 at the front end 21 the belt shaft 22 engages coaxially through the hub opening under radial play 17 of the drive wheel 13 through to at least the axial cross-sectional plane through the pawl tooth profile 19 one.

In the projection of the hub opening 17 controlled, stands the tooth profile 19 the clutch pawl 16 with the geometrically corresponding outer toothing 20 the belt shaft 22 engaged. That's why the belt shaft 22 then with the rotational speed of the motor-driven drive wheel 13 in belt winding - so clamping direction of rotation 24.1 emotional. How out 1a can be seen, it supports the controlled front end 18 the clutch pawl 16 positive fit against the drive wheel 13 off, about here about their Schwenklager 15.1 approximately diametrically opposite to the drive wheel 13 anchored or trained pillars 15.2 as a tax stop 36.1 , Between the drive and the drive wheel 13 usually there is at least one geared transmission element 23 such as B. a spur gear.

The retaining ring 12 is so far divided into two axially, as on him in principle the same acting, here so-called blocking ring 37 rests with the same rotation angle game.

One to the system axis 28 coaxial clutch control ring 25 is in principle non-positive with the blocking ring 37 connected. Preferably, the control ring 25 designed as a centrifugal expansion ring. The can be against a concentric support on the blocking ring 37 issue; if not as outlined in a hub opening 35 of the blocking ring 37 is coaxially sunk. In order to increase the spreading force, so the centrifugal contact pressure against the surrounding ring 37 , is the tax ring 25 for clamping a pressure-elastic (screw) spreading spring 26 interrupted. Also, more concentric expansion rings are suitably equipped with such expansion springs (not visible in the drawing). All rings and wheels are preferably made by plastic injection molding.

The clutch pawl 16 stands with the tax ring 25 positively displaceable in connection. That's what the tax ring is for 25 , Preferably on its inner circumferential surface, a Umsteuer- and entrainment profile 27 educated. About that and the clutch pawl 16 support the drive wheel 13 and the tax ring 25 form-fitting against each other, by the clutch pawl 16 a molded or attached rib 29b in the profile 27 intervenes. In the illustrated, preferred implementation example of this procedure 29 for pawl swivel control act for the two legs 29a of the u-like limited, centripetal opening tax profile 27 with the between the thighs 29a engaging rib 29b together. The slope of the leg inner surfaces relative to one another outlined in the drawing is the kinematics of the rib 29b in the course of the input and output swivel movements of the clutch pawl 16 owed.

If the according to 1a on the stop 36.1 controlled clutch pawl 16 due to external drive of the drive wheel 13 in one-turn direction 24.1 around the system axis 28 is turned, takes the drive wheel 13 over the top of the leg in the drawing 29a the Umsteuerprofiles 27 positive locking the control ring 25 with - under sliding friction the play stop twisted and then stationary blocking ring 37 across from; while at the same time the controlled clutch pawl 16 the belt shaft 22 in winding direction 24.1 rotates.

Once as a result of program-controlled drive reversal of the rotary motion 24 the drive wheel 13 in the direction of rotation 24.2 changes, learns the control ring 25 due to the reversal of motion a temporary stoppage, which is why its previous sliding friction in stiction to the blocking ring 37 replaced. The inevitable with the drive wheel 13 twisted clutch pawl 16 now supports herself with her rib 29b against the lower of the two thighs 29a on until then temporarily stationary profile 27 the tax ring 25 from; and the backdrop of this procedure 29 then pivots the clutch pawl 16 until against a drive wheel fixed drive stop 36.2 , thus under the influence of their gearing 19 from the sheath toothing 20 the belt shaft 22 out. With further twisting of the drive wheel 13 in the direction of rotation 24.2 will be against the attack 36.2 supported tax ring 25 , under transition from static friction to sliding friction the stationary locking ring 37 opposite, due to the positive reversing intervention 29 rotated; the gearing 19 - 20 the clutch pawl 16 to the belt shaft 22 remains until the next reversal of direction 24.2 => 24.1 modulated.

Every time the drive wheel is returned 13 in the winding or belt tensioning direction of rotation 24.1 supports the clutch pawl 16 with her rib 29b against the upper of the thighs 29a at the Umsteuer profile 27 the entrainment procedure 29 opposite the still non-locking stationary control ring 25 from. This pivots the clutch pawl 16 from the drive stop 36.2 back against the entry stop 36.1 ; then to the control profile 27 the tax ring 25 , under sliding friction the locking ring 37 opposite, as well as the belt shaft 22 positively with the drive wheel 13 in one-turn direction 24.1 take.

But if the belt shaft 22 under meshing intervention 19 / 20 very strong in the winding direction 24.1 is accelerated, in particular because an approximately pyrotechnic drive (not shown) briefly on the belt shaft 22 then the sawtooth profile hurls 20 on the outer surface of the belt shaft 22 the corresponding sawtooth profile 19 the clutch pawl 16 out of engagement - namely the frontal area 18 around the storage pillar 15.1 around to the outside, from the central system axis 28 the coupling device 11 continued.

To any damage or malfunction due to rebound of the pawl front end 18 to the toothing 20 on the belt shaft 22 to avoid and the latch 16 to fix in a defined driving position, is a reversible catching device 30 between the clutch pawl 16 and the device-fixed retaining ring 12 intended. The catcher 30 according to 3 at the clutch pawl 16 a centrifugally oriented, for example at the free end of the front 31 buttoned tentacle 32 on. The acts with a fishing hook 33 together, which in turn of a catch ring 34 centripetally projecting. tentacle 32 and fishing hooks 33 In this case, they can also be geometrically reversed.

Because of geometric details regarding the design of the adhesive and sliding co-operating rings 12 . 25 . 34 . 37 in relation to each other is on their sectional representations in 2 and 3 the drawing reference.

The plastic injection molding, here on its inner surface, with the fishing hook 33 trained catching ring 34 lies opposite the tax ring 25 axially offset, centrifugally frictionally against the retaining ring 12 preferably also using a spreading spring (not visible in the drawing; 26 ).

The tentacle 32 and the fishing hook 33 are in the controlled normal mode (in the direction of rotation 24.1 , like out 1 visible) slightly against each other rotational angle offset. As a result, they only engage in mutual intervention, if - not the regular about the tax profile 27 controlled, but - a pulse-generated pivoting of the clutch pawl 16 in which, thereby further expansive, modulation leads.

If after that the drive wheel 13 (with the now up to the catcher 30 in controlled clutch pawl 16 ) relative to the retaining ring 12 in one-turn direction 24.1 is turned further, is the drive wheel 13 positive locking via the intervention 29 the tax ring 25 and of this over a not visible in the drawing stop the catch ring 34 rotated; the catcher 30 remains therefore, when gearing is controlled 19 - 20 , in function.

When reversing the motion in the direction of rotation 24.2 of the drive wheel 13 remains the clutch pawl 16 according to regulations. But while the tax ring 25 now due to positive engagement of the reversal 29 and consequently also the clutch pawl 16 immediately with the drive wheel 13 Turn back, the catch ring goes 34 when reversing the direction of rotation in static friction with the stationary retaining ring 12 over and therefore initially also stands. By this relative rotation pivot the tentacle 32 at the clutch pawl 16 and the fishing hook 33 at the catch ring 34 against each other; namely, from their previous, mutual latching out stop due just in the original, small mutual angular misalignment into it. About this stop (not apparent from the drawing) is then the catching ring 34 while maintaining that angular offset 32 / 33 from the drive wheel 13 in its driving direction of rotation 24.1 taken.

When the drive wheel 13 , After the short-acting Eilantriebes has faded away, then once again in the driving direction 24.1 reversed, is now the catcher 30 out of engagement. The clutch pawl 16 can therefore again by means of the tax profile 27 against the currently friction-locked stationary control ring 25 turn on and off the drive wheel 13 the belt shaft 22 drive.

In addition, a blocking device is preferred 44 intended. That causes the clutch pawl 16 can only turn on when their catching device 30 already taken the ready angular position; and that the ready position due to pivoting of the tentacle 32 is abandoned from this angular position only when the clutch pawl 16 is already controlled. This ensures that the catching device 30 with activated clutch pawl 16 always ready.

To realize this, here is the kinematics of the catching ring 34 resorted. At the, about again on the inner surface 41 , is to over a certain arc length zentripetal applying blocking base 42 attached or molded. The acts as sketched, with the free front end 43 one - to tangential behind the beginning of the approaching blocking base 42 about L-shaped angled - blocking arm 40 together, which at the clutch pawl 16 attached, preferably also formed. In the example case outlined in the example designed as a one-armed lever clutch pawl 16 becomes so as a result of the blocking arm 40 over her pivot bearing 15.1 extended to the unbalanced two-armed, non-linear lever.

In one-turn direction 24.1 of the drive wheel 13 becomes the clutch pawl 16 swiveled to the entry - but initially prevented from entering. Because there in the path of movement of the latching locking arm 40 the base 42 at the catch ring 34 is located, the blocking arm is running 40 centrifugal on this, causing a further pivoting of the clutch pawl 16 prevented in the control. The blocking arm 40 only then runs from the blocking socket 42 down (and the clutch pawl 16 device engages with the belt shaft 22 ) when the tentacle 42 at the clutch pawl 16 and the fishing hook 33 at the catch ring 34 in Einsteuerdrehrichtung 24.1 the clutch pawl 16 the predetermined mutual angular position to catch a pulse output of the clutch pawl 16 have taken. This angular position still exists when switching to the direction of rotation 24.2 the clutch pawl 16 modulates.

In a coupling device 11 for the belt shaft 22 a belt tensioner system with one, stationary mounting and locking rings 12 / 37 opposite, motor-driven drive wheel 13 So it is on this to drive the belt shaft 22 Offset a clutch pawl 16 pivoted, the at the front end 18 with a tooth profile 19 for driving into a corresponding sheath toothing 20 on the in the hub opening 17 of the drive wheel 13 Coaxially protruding belt shaft 22 Is provided. When reversing the drive direction of rotation 24.1 / 34.2 of the drive wheel 13 , to change between input and output control of the gear meshing 19 - 20 by pivoting the clutch pawl 16 against drive wheel-fixed attacks 36.1 respectively 36.2 , is a tax ring 25 with Umsteuer- and entrainment profile 27 for the clutch pawl 16 temporarily adhesive-locked with the stationary blocking ring 37 connected.

A catching device 30 for the clutch pawl 16 serves the radial locking but peripheral release of the short-time rush drive the belt shaft 22 impulsively controlled clutch pawl 16 , which with umsteuertedem release from the catcher 30 automatically returns to regular Umsteuerbetrieb. But as long as the modulation not impulsive, but only direction of rotation occurs, the catcher occurs 30 not in action; because their tentacle 32 and fishing hooks 33 because of their mutual angular misalignment, they do not mesh with each other when the clutch pawl 16 only as a result of their intervention in the profile 27 at the control ring 25 controls, the current during the reversal due to friction in the stationary blocking ring 37 stationary.

The interaction of a blocking arm 40 at the clutch pawl 16 with a peripherally displaceable stop blocking base 42 at the catch ring 34 Make sure the clutch pawl 16 only opens when the catching device 30 the angle between tentacle given for their function 32 and fishing hooks 33 has taken, and that this angle until the disengagement of the clutch pawl 16 maintained.

LIST OF REFERENCE NUMBERS

11

Coupling device (for 22 )

12

Retaining ring (fixed to device)

13

Drive wheel (with 16 )

14

Cover (by means of 15 raised up 13 )

15

Pillars (from 13 to 14 ); 15.1 Warehouse (for 16 )

16

Clutch pawl (on 13 swiveling around 15.1 )

17

Hub opening (in 13 )

18

swiveling front end (from 16 )

19

Tooth profile (on 16 at 18 )

20

(Shell) toothing (up 22 )

21

Forehead (from 22 )

22

Belt shaft (in 17 so as to project)

23

Transmission element (eg toothed ring of 13 )

24

Direction of rotation (from 13 in relation to 12 / 37 );

24.1

A control rotation direction,

24.2

Modulation rotational direction

25

Control ring (with 27 )

26

Compression spring (in 25 )

27

Umsteuer- and entrainment profile (with 29a / 29a at 25 ) For 16 With 29b

28

(System) axis (from 11 )

29

Intervention (for 16 )

29a

U-thighs (from 27 at 25 );

29b

Rib (on 16 , between 29a - 29a from 27 )

30

Catching device (for 16 , between 16 and 34 )

31

Forehead area (from 32 )

32

Tentacle (on 16 )

33

Fishing hook (on 34 )

34

Fangring (for 30 )

35

Hub opening (in 37 ; corresponding 17 ) With 25

36

Umsteuer-stops (for 16 on 13 );

36.1

A control-stop,

36.2

Dowry-stop

37

Blocking ring (fixed to the device)

38

39

40

Blocking arm (on 16 )

41

Inner circumferential surface (from 34 )

42

Blocking base (on 41 , at 40 )

43

Forehead (from 40 )

44

blocking device

Claims (9)

Coupling device ( 11 ) for the belt shaft ( 22 ) of a belt tensioner system with one, a stationary retaining ring ( 12 ) to a system axis ( 28 ) rotatable drive wheel ( 13 ) parallel to the system axis ( 28 ) displaces a coupling pawl ( 16 ) is pivotally mounted, which at its front end ( 18 ) with a tooth profile ( 19 ) for driving into an outer toothing ( 20 ) on the belt shaft ( 22 ), wherein for reversing the gearing ( 19 - 20 ) with a reversal and carryover profile ( 27 ) for the clutch pawl ( 16 ) equipped control ring ( 25 ) with a stationary locking ring (FIG. 37 ), characterized in that for a pulse-like controlled clutch pawl ( 16 ) a catching device ( 30 ), with one on the coupling pawl ( 16 ) centrifugally oriented tentacle ( 32 ) and angularly offset with one of a catching ring ( 34 ) centripetally projecting catch hooks ( 33 ), the catching ring ( 34 ) against the tax ring ( 25 ) axially offset and, for peripheral release of the pulse-like controlled clutch pawl ( 16 ) from the capture device ( 30 ), temporarily with the retaining ring ( 12 ) is connected in a friction-locked manner. Coupling device according to the preceding claim, characterized in that the control ring ( 25 ) and the catching ring ( 34 axially adjacent to each other as expanding rings in the hub opening ( 35 ) of the blocking ring ( 37 ) or the retaining ring ( 12 ) are used. Coupling device according to one of the preceding claims, characterized in that in the driving-in direction of rotation ( 24.1 ) with the coupling pawl ( 16 ) positively engaged control ring ( 25 ) then with the catching ring ( 34 ) is positively engaged. Coupling device according to the preceding claim, characterized in that when changing over to the direction of rotation ( 24.2 ) the drive wheel ( 13 ) only after a certain angle of rotation relative to the catching ring ( 34 ) under pivoting of tentacle ( 32 ) and catch hooks ( 33 ) of the catching device ( 30 ) out of their mutual locking with the catching ring ( 34 ) engages positively. Coupling device according to one of the preceding claims, characterized in that the catching ring ( 34 ) with a blocking base ( 42 ) equipped with a locking arm ( 40 ) on the clutch pawl ( 16 ) in the sense interlocking effect that their Einsteuern only when already prepared and their dues only with still prepared catching device ( 30 ) is no longer positively locked. Coupling device according to the preceding claim, characterized in that the blocking arm ( 40 ) an angled, against the approaching blocking base ( 42 tangentially trailing front end ( 43 ) having. Coupling device according to one of the preceding claims, characterized in that the control ring ( 25 ) while reversing the clutch pawl ( 16 ) with frictional locking with the blocking ring ( 37 ), however, from reaching a reversal stop ( 36.1 respectively 36.2 ) on the drive wheel ( 13 ) with this form-fitting, and now sliding frictionally with the blocking ring ( 37 ), connected is. Coupling device according to one of the preceding claims, characterized in that the coupling pawl ( 16 ) over a rib ( 29b ) between the thighs ( 29a ) of a U-shaped centripetally opening profile ( 27 ) on the control ring ( 25 ) is engaged with this. Coupling device according to one of the preceding claims, characterized in that the coupling pawl ( 16 ) about an axis-parallel on the drive wheel ( 13 ) ( 15.1 ) is pivotally mounted, wherein it in controlled stop ( 36.2 ) a portion of the hub opening ( 17 ) surrounds arcuate, but controlled by overlapping the hub opening ( 17 ) against a stop ( 36.1 ) on the drive wheel ( 13 ) is supported.

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