EP1329582A1 - Automatic stopping device for an electric motor fitted into a rotational tube and designed especially for actuating a roller shutter - Google Patents

Abstract

The automatic stop device includes flexible elements which allow the casing to pivot in reaction to the couple appearing on the output of the speed reducing gear. When the pivoting action reaches a set angular value, the electrical supply to the motor is interrupted. The automatic stop device for an electric motor in a roller blind forms a junction between the casing (1) of the motor and a fixed mounting point. It includes flexible elements which allow the casing to pivot in reaction to the couple appearing on the output of the speed reducing gear. The opposing pivoting movements of the casing attain a particular angular extent, then interrupt the supply to the motor. The levels of couple attained when the motor is turning in the two different directions are different. The mechanism includes a device for modifying the action on the flexible elements (6) in order to reverse the levels of couple and adjust the equilibrium position of the motor casing.

Description

The present invention relates to a device that automatically stops an engine electric housed in a rotating tube which actuates a moving element and more especially a roller shutter.

Roller shutters powered by an electric motor whose power is simply programmed so that the winding tube carries out a determined number of revolutions are always at risk of being damaged when their operation comes to jam. Such an incident occurring in the absence of human surveillance, due to a automated operation or a general control grouping several components, a often for consequence of keeping blocked the engine whose shutter could not complete its cycle, which very quickly puts it out of use, or seriously deteriorate the shutter.

Improvements have therefore been made to replace the machines that are waiting simply the end of the run of the aprons to cut the power supply to their engine, by devices that cause this cut-off when a overload or an obstacle to the movement of these mobile elements. Means of blocking, at the end of the stroke, then makes it possible to trigger the stopping of the motors free these from any analog device that requires adjustment to reproduce the race of the apron.

Various means make it possible to obtain such a stop. The simplest are based on the measurement of the torque released by the motor, from the deformation of an elastic connection between the casing of its stator and the fixed point which retains it.

However, these devices have limited torque capacities because, given that one of the directions of rotation of the motor has the function of retaining the windable element during its descent, they must be able to detect the appearance of a very weak couple of opposite direction to that generated by the weight of the bulkhead so that the malfunction does not not become irreversible. This assumes that the elastic modulus of the spring (s) does not is not too high but it is then difficult, in the opposite direction, to obtain torque without rendering the very bulky device. In addition it is important that the sensitivities to the triggers stops are interchangeable.

Finally, the braking of the geared motors releasing a high torque whose level must to continue to maintain the stop always presents a risk. Indeed, the stability of the stop rests on the brake which is constantly used at its maximum. If this one comes to slip, there is a retrograde movement of the rotor which restarts the engine. A brake failure can therefore cause continuous jerks and cause engine damage.

The invention overcomes these difficulties.

A device according to the invention comprises a junction between the motor casing and a fixed point which allows the casing to pivot, in reaction to the torque appearing at the outlet of the speed reducer, swivels of a determined amplitude triggering the stop of the motor. The main characteristic of this device is that the housing of the motor not being the object of any request, this one presents an equilibrium position, from which the opposite direction swings that cause it to stop the motor have the same amplitude, its junction at the fixed point opposing resistances different to these moves.

• les résistances aux pivotements du carter, différentes selon son sens de déplacement à partir de sa position médiane, peuvent être interverties par une manipulation du tube rotatif déjà installé,
• la manipulation du tube rotatif peut comporter au moins une rotation entraínant un déplacement de l'élément normalement fixe de l'appareillage de coupure d'alimentation du moteur, tel le berceau qui porte les interrupteurs ou le levier qui les actionne, le carter adoptant alors une nouvelle position médiane de pivotement,
• le moyen par lequel les éléments flexibles qui retiennent le carter sont soumis à une déformation peut être désactivé par un mouvement latéral du tube rotatif, lors de sa manipulation, afin que son mouvement de rotation puisse être conduit sans que ces éléments n'en contrarient la menée à terme,
• un jeu existant, pour un sens de pivotement du carter à partir de sa position médiane, dans l'engrènement de sa jonction avec les éléments flexibles qui le retiennent, la manipulation du tube rotatif peut modifier l'engrènement de la jonction avec les dits éléments flexibles, d'une façon telle que le jeu est reporté sur l'autre sens de pivotement du carter, sans modifier sa position médiane de pivotement,
• les manipulations du tube rotatif peuvent être encadrées par des butées,
• la fermeture de celui des interrupteurs d'alimentation, dont l'ouverture a provoqué l'arrêt du moteur en fin de course, peut s'opérer pour une position du carter en retrait de sa position extrême de pivotement,
• le moteur tournant dans le sens qui demande de sa part le plus d'effort, l'atteinte du couple limite peut être suivie par une diminution de la résistance que les éléments flexibles opposent au pivotement du carter, celle-ci étant obtenue avant l'arrêt du moteur.

According to particular embodiments:

• the resistances to the pivoting of the casing, which differ according to its direction of movement from its central position, can be inverted by manipulation of the rotary tube already installed,
• manipulation of the rotary tube may include at least one rotation causing displacement of the normally fixed element of the engine power cut-off device, such as the cradle which carries the switches or the lever which actuates them, the casing then adopting a new central pivot position,
• the means by which the flexible elements which retain the casing are subjected to deformation can be deactivated by a lateral movement of the rotary tube, during its manipulation, so that its rotational movement can be carried out without these elements opposing the completed,
• an existing clearance, for a direction of pivoting of the casing from its median position, in the meshing of its junction with the flexible elements which hold it, the manipulation of the rotary tube can modify the meshing of the junction with the said elements flexible, in such a way that the clearance is transferred to the other direction of pivoting of the casing, without modifying its median pivoting position,
• the manipulations of the rotating tube can be framed by stops,
• the closing of that of the power switches, the opening of which caused the engine to stop at the end of its travel, can take place for a position of the casing set back from its extreme pivoting position,
• with the engine rotating in the direction which requires the most effort from it, reaching the limit torque can be followed by a reduction in the resistance which the flexible elements oppose to the pivoting of the casing, this being obtained before the engine shutdown.

The accompanying drawings illustrate the invention.

Figure 1 shows a view along a section along the part of a housing motor containing the stop device according to the invention; Figure 2 shows a section through this device and Figure 3, a view of its end located in depth in the housing.

Figure 4 shows a view of a variant of the device in a longitudinal section of the casing, FIGS. 5 and 6, views of the engagement parts of the junction of this variant of the device with its flexible elements and FIG. 7 a specific switch for this first variant of the device.

Figures 8, 9 and 10 relate to another variant of the invention. They represent cuts similar to the basic version.

We refer to FIG. 1. The motor and its speed reducer, not shown, are housed in a cylindrical housing (1), a wheel at the outlet of the reducer, driving the rotary tube (2) into which the housing (1) is fully inserted. A deformable junction (3) links the casing (1) to an axis (4) whose projecting end (5) is intended to connect to a fixed point. Normally, this side of the housing is centered in the rotating tube by the sequence of the axis of its junction with that of a stroke limiter housed in a independent drum. This element, not shown, then forms an end piece for the tube. rotatable and ensures centering of the axis of the junction. It is intended to create the obstacle, in the end when the stop will be triggered, the stresses due to the remaining blockage then internal to the rotating tube.

The junction (3) comprises flexible elements (6) equidistant from each other, consisting of bars each provided with a roller (7) coming into contact with the axis (4). Cams (8), in a number equal to that of the rollers (7), fill so regular around the axis (4) by being inserted between the rollers.

Two shells (9) each connected to the casing (1) laterally frame the assembly rollers (7) to place them in the center of the bars (6). These shells (9) hold the ends of the bars (6) by constraining them to bending prerequisite which increases by the rise of the rollers (7) on the cams (8). The bending of bars (6) is guided by the shells (9) so that the distance of the rollers (7) takes place radially around the axis (4). When the rollers (7) are in a area from the foot of one cam (8) to that of another cam, it is possible to move laterally the rotary tube (2) which then drives the casing (1) by the drive wheel, not shown, of the motor reducer linked to this rotary tube (2). Such displacement drives the shells (9) and their content, bars (6) and rollers (7), which then slide on the axis (4) of the junction (3). This sliding is counteracted by a spring (10) placed in one of the shells (9), but, when obtained, it allows the rollers (7) to turn on a cylindrical part of the axis (4) escaping from the cams (8). Lateral displacement of the housing is limited by the mating of the cams with the bottom of the countersink provided in one hulls. It is carried out by preferentially pressing the axis into it, the axis of the rotary tube located on the side opposite the motor being telescopic with the consequent end of the tube.

Figure 2 provides a view of one of the shells (9), by its side adjoining the other shell and from which it is separated by the thickness of the rollers (7). In the case presented, the there are two bars, but we will see that their quantity can be increased. Depending on the desired torque, the device will therefore be fitted with as many bars as necessary, their diameter may also vary.

Figure 3 provides a view of the end of the device located deep in the casing with the means for interrupting the electrical supply to the engine. These means consist of two switches (11) between which is placed a lever (12). The switches are sealed on supports (13) belonging to the shell (9) whose base is visible here. They are therefore movable in rotation with the casing, while the lever (12) is held by the fixed axis (4) of the junction (3) with a tightening making its orientation precarious. Also, facing a push of the supports (13) of the switches (11), this lever (12) pivots after that he has depressed the switches of the switches (11).

If we consider Figure 2, an angular location with respect to the cam wheel determines four positions for a caster moving from the top of a cam to that of a neighboring cam, stopping at their foot. A movement leading its center to pass from position A to position B encounters strong resistance, due to the rise of all the casters on their cam. On the other hand, a movement of the casing in the same way amplitude but in opposite direction does not offer significant resistance. Movements inverses after the wheel has been brought to A 'lead to the same effects, too, when the caster is in one or other of the positions A and A 'the casing is in a position pivot median insofar as the movements just considered stop the engine. We will therefore arrange for the gaps between the sides of the lever and a trigger position of the push-button of each switch correspond to these considered movements of the housing.

In Figure 3, we see that the extreme limits of pivoting are bounded by stops (14) belonging to the shell (9) carrying the switches (11), which strike a fixed arm (15) linked to the axis (4) in an irremovable manner. The housing has not moved by compared to FIG. 2, but the angular location has been shifted so that it is opposite the stops, and, in this case, the device provides resistance to a rotation of the casing which is carried out clockwise.

In order for this resistance to affect rotation in the opposite direction, manipulation of the rotating tube will first consist of a lateral displacement which allows the rollers to escape from the cams, then in a rotation bringing the rollers from position A to B '. During this rotation, the casing (1) will sweep a much more angular sector vast as the space available between the lever (12) which actuates the switches (11) and their support (13). Note in Figure 3 that the switch concerned is on the left. The lever (12) which is normally fixed will therefore be driven by the support (13) of the switch (11) during this rotation and a return back bringing the rollers (7) below the position A 'will allow their reintroduction between the cams (8).

Several remarks should be made here.

The resistance of the device to the displacement of the casing depends on the component eccentric of the movement of the casters which drops very quickly to become zero when these have reached the top of the cams. The torque resistance of the device therefore starts from a maximum and then weakens, even if the bending of the bars increases. This feature is therefore advantageous insofar as the torque remains after engine stopping is significantly reduced. However, we arrange for a imbalance tends to spontaneously lower the rollers of their cam.

On the other hand, the space between the cams must allow the housing to be moved at less equal to that required by the torque generating phase. To the extent that this space is greater, it is not advised that the middle pivot positions correspond to a position of the casters attached to the feet of the cams. We can, in effect, adjust the distance between the switches in order to obtain a stop, on the one hand, when the maximum torque has been exceeded enough, on the other just before a resumption of reverse torque due to the meeting of the rollers with a neighboring cam. In this way, the rotating tube will have very little free play when it stops after turning in the sense that the device does not generate resistance to this stop.

The middle positions will then be in the area where the rollers are spaced cams and a slight vacuum rotation will precede the appearance of the torque, in the direction who is called upon to produce them. These median positions will no longer completely coincide with the marks A and A 'in figure 2, but they will always correspond to positions of the housing where, in the absence of stress, it is in equilibrium. On the other hand, the space between the stops will depend on the extreme pivot positions defined by the position chosen for the casters, more or less cantilevered at the top of the cams, and we will also take into account the crushing of the push-button switches which has exceeded the opening of the contacts during the movement of the lever which controls them to establish the precise position of these stops.

To show that the embodiments of the device can be very diverse, we will still describe two forms with very different conceptions.

In the variant illustrated in FIGS. 4 to 6, the flexible elements (6) are always bars arranged equidistantly around the fixed axis (4) of the junction, parallel to it, their deformation no longer taking place radially but tangential to the rotation and proportional to it. The ends of these bars (6) are fixedly held by two fixed wheels (18), locked on the axis (4) of the junction, here formed by a simple square tube. These wheels form spans on which the casing (I) can rotate and slide longitudinally. The flexible bars (6) cross the sides of two rings (16,17), one of which (16) is pinned to the housing. The other ring (17) remains on a defined location of the axis (4) while being able to rotate on it, and, to do this, this ring (17) consists of two elements joined by screws (19) which enclose a elastic ring (20) positioned on notches made in the edges of the axis (4) to equidistance from the fixed wheels (18). The thickness of the wire of this ring is distributed between a throat of the ring and the notches of the axis. A spring (10) placed between a fixed wheel (18) and the ring (16) linked to the casing (1) tends to expel the fixed wheel (18) out of the latter, but the axis (4) which holds it is retained by the ring (17) locked longitudinally on it which found pressed against that (16) from which the spring (10) is supported. A depression of the axis in the housing therefore causes the spacing of the two rings in compressing the spring.

The ring (16) linked to the casing has oblong lights (22) in the form of arcs of circle. These lights (22) are centered on the circle passing through the center of the bars (6). They are all identical and equidistant from each other. The second ring (17) has the same number of lights (23), of the same shape, but the latter represent a smaller angular sector, the screws (19) which are used for its assembly interposed between these lights (23). These screws (19) have a body which extends out of the total thickness of this ring (17), their point forming lugs which are introduced in the big lights when the bugs are side by side. Either screw (19) neighboring a small light (23) of a ring (17) can then be alternately engaged in the same large light (22) of the other ring (16), occupying a corner or the other of it, and that, respectively, for each pairing of screws.

The lights (22,23) of the two rings (16,17) are such that, these rings being separated from each other, that (16) provided with large lights (22) can, without deforming the bars (6), pivot on an angular sector twice as large as the ring (17) provided with small lights (23), and, joined together, they can rotate together all the play allowed by the small lights (23). The game provided by small lights in the engagement of the rings with the bars will affect one or the other direction of pivoting of the casing from a central pivoting position common, obtained when the bars (6) occupy the center of the large lights (22).

If, during installation, there is a bad adjustment, a depression of the axis (4) in the casing (1) which separates the second ring (17) from the first (16) followed by a rotation of the casing (1) driving the ring (16) linked to it will see the bars (6) retain the ring (17) carrying the screws (19), which will allow the large lights (22) to accommodate different screw tips (19) and the small lights will be pushed back facing each other half of the big ones.

Furthermore, a buffer (25), linked to the casing (1), is placed equidistant from two switches (11) when the bars (6) occupy the center of the large lights (22). The engine stops will therefore be obtained with identical pivoting of the casing and under opposite couples whose value of one is zero and the other strong.

The manipulation of the already installed rotary tube can find its limit, laterally, by the crushing of the spring (10), as well as by stops (14) which restrict the rotation of the ring (16) linked to the casing when they meet the edges of the square axis (4). The spaces between the switches and the buffer that activates them will be such that the engine stops are triggered just before these stops act, however these can be suppressed insofar as the device leans against a resumption of torque due to reverse bending of the bars which is obtained even when the two rings (16, 17) are dislocated.

The said torque recovery may be interesting in the case where a certain pressure must be exerted on the apron at the end of closing. We will then accommodate low sensitivity of the device to cause a stop in the event of an obstacle to the descent. An increased gap between the switches and the buffer will create this effect.

We can also provide that the tampon does not have a constant thickness and that its position can be changed in the housing to obtain a sensitivity adjustment.

The number of bars, their length and their section are all variables that achieve the desired torque, which can be very high here, but, as has been said, stopping the engine on such torque is a factor in malfunction, in the event of loss of braking. Also, it will be prudent to plan for this embodiment of particular switches whose operating principle is illustrated in Figure 7, which will secure the engine stops by the fact that the contact closure of these switches corresponds to a recessed position of the housing from the extreme position he had to reach to get their opening.

This is obtained with a switch, the swing lever of which carries one of the contact pads (26) is a stirrup (27) which holds a leaf spring (28) against a fixed support (29), surrounding this spring and this support. Spring edge (28) resting on the support (29) has an invariable position on it, so that, when the loop of the stirrup (27) which slides on the back of the support (29) comes and goes around this spring support position, the floating loop of the stirrup (27) which holds the free end of the spring (28) rocks back and forth under the effect of said spring.

To give better precision when crossing this critical position, the loop of the stirrup (27) which surrounds the support (29) is provided with a roller (30) and the back of the support (29) on which this roller (30) travels is slightly convex at the place where the spring presses.

Pressure exerted on the pusher (31) which projects out of the housing (32) of the switch acts on the movement of the roller (30) only from a certain recess in the housing, due to a recess (33) in the body of the pusher (31) which creates a delay before it takes effect. Also, as soon as the roller (30) has exceeded the support position of the spring (28) on the support (29), the stirrup (27) escapes entirely in opening the contact (26). When the pressure on the pusher (31) is released, another spring (34) pushes the latter out of the housing but the reverse tilting of the caliper (27) does not takes place only after catching up with the delay due to the recess (33) of the pusher and which now applies the other way around. Contact (26) will therefore be closed for a clearly more prominent position of the pusher (31) out of the housing (32) than for its opening.

As an indication, a beat of three millimeters will reduce the residual torque of the junction of about a third in the case of the variant of the invention.

A third embodiment of the invention will also be described, which presents a different mounting of its power cut-off elements.

Figure 9 is a cross-sectional view of the junction of the housing to the fixed axis which equips this second variant. The flexible elements (6) consist of steel plates locked in the housing (1), equidistant from each other, by reliefs (35) generated by a puncture with depression of the wall of the casing. The width plates (6) is such that, their edges bearing on the internal wall of the casing (1) and their center on cylindrical sectors of a grooved tube (36), they must bend slightly to be introduced into the housing. The grooves in the tube (36) are numerous equal to that of the plates (6) and receive rollers (37) which partially emerge out of these gorges, over their entire length. The grooved tube (36) contains another tube cylindrical (4) which forms the fixed axis of the Carter junction. The rollers (37) are housed between the plates (6) when the junction is at rest, and a rotation of the casing (1), then that the rollers (37) and the grooved tube (36) maintain a fixed position, causes the eccentric bending of the plates (6). The central part of these plates (6) can have a boss (38) forming an obstacle intended to increase the torque.

A fallout of the torque appears when the rollers have crossed this obstacle, from the same way as in the first version of the device. To further increase the resistance of the device, rods (39) of elastomeric material can be inserted between the flexible plates (6) and the housing (1), the deformation of the plates resulting in crushing of these rods. We will therefore play on the thickness of the plates and the presence, or not, of bosses or rods to vary the torque resistance, the hardness of the elastomer being also a setting factor.

We consider Figure 8 where we see that the grooved tube (36) constitutes a spacer between two flanges (40) which it connects to each other, which form spans for the casing (1). The flexible plates (6) are contained between the flanges (40) which, themselves, are trapped between retainers of the casing (1). The housing (1) can rotate on these flanges (40) and if it moves laterally it drives them with it, the grooved tube (36) being able, on its side, to slide on the fixed axis (4). To facilitate mounting of the motor in the casing (1) it will be preferable to accommodate the junction (3) in a part separable from that which contains the motor and to reunite these two parts by a sleeve (41). The collar (40) located near the sleeve (41) has an imprint in which a dog is nestled (42) linked to the fixed axis (4) of the junction (3). A spring (10) acting between this dog (42) and the sleeve (41) which reunites the casing (1) tends to hold the dog clutch (42) in its niche.

On the other hand, the end of the fixed axis (4) internal to the casing carries a cradle (44) to which the switches (11) are attached. This cradle (44) is held by a pin (45) engaged in the core of the fixed axis (4) in which it can rotate with friction. To facilitate the realization of the cradle, it is advantageous to make it in two parts, the switches being parallel to each other. Two fingers (12), visible in Figure 10, from the sleeve (41) connecting the casing (1), will be provided to actuate them. Through elsewhere, stops (14) formed in the same sleeve (41) limit the amplitude of the swivels that can be given manually to the housing. These stops (14) cooperate with the stud (43) of a ring (46) linked to the fixed axis (4).

A lateral displacement of the casing (1) which aims to push in the axis (4) of the junction (3) within it causes the spring (10) to be crushed and the dog clutch (42) to exit from the collar (40). We can then rotate the rotating tube by hand to move the centering of the cradle on another median pivot position, which will bring the plates to change support roller just like the casters of the first form of realization changed cam. The operation here is perfectly identical. and we will therefore not repeat its entire explanation.

Let us simply note that Figures 9 and 10 show that the casing has already largely left its central pivoting position when the plates come into contact with the rolls. Indeed the fact of deforming the plates requires a rotation of the casing much less important than that causing the plates to leave a roll for come into contact with a neighboring roller. However, we know that to remove the empty game, it is necessary that the stop obtained without resistance occurs when the junction is backed by its resumption of resistance. We also know that for the housing to be in its middle position, the the distances separating each switch from its actuating finger are similar. By taking a moving pointing with the casing, we see on figure 9 that the position median relative to the scenario is obtained when this score starting from A is positions in the vertical plane, which moves the plates away from their roller.

Starting from this middle position, the casing will therefore begin to pivoting without its junction presenting resistance against the torque.

Claims (9)

Device automatically stopping an electric motor housed in a rotary tube which actuates a mobile element and more particularly a rolling shutter, this device forming the junction between the motor casing and a fixed fulcrum and having flexible elements which allow the casing to pivot in response to the torque appearing at the output of the speed reducer, the opposite pivotings of the casing which reach a determined amplitude from an angular position in which the flexible elements are at rest interrupting the supply of the motor and the action of the device on the flexible elements being such that the levels of torque reached at the time of triggering the stopping of the motor rotating in one or the other direction are different, characterized in that , on the one hand, being mounted to operate with a given correlation between the levels of stopping torque and the directions of pivoting of the casing (1), it has a hub n to modify its action on the flexible element or elements (6) capable of inverting the levels of stopping torque in the said correlation, on the other hand, there is always, whatever the mounting, an equilibrium position at vacuum of the casing (1) from which its opposite pivotings which trigger an engine stop have the same amplitude. Device according to claim 1 characterized in that , on the one hand, two adjacent support elements (8 or 37) are capable of acting in the same way on the same flexible element (6) of the junction (3) with reverse pivoting of the casing (1), a pivoting of the latter encountering no significant resistance as long as the flexible element (6) is not attacked by one or the other of the support elements (8 or 37) and the choice of the levels of stopping torque relating to the directions of pivoting being obtained by causing the flexible element (6) to be deformed by one or other of the support elements (8 or 37), d 'on the other hand, there are two positions for the normally fixed element of the electrical power cut-off device of the engine, such as the cradle (44) which carries the switches (11) or the lever (12) which actuates them, the displacement of this element (11 or 44) normally fixed, from one to the other of its two positions, obtaining that the flexible element (6) , which was deformed by a support element (8 or 37), when the casing (1) pivoted from its initial median pivoting position, is by the other element (8 or 37) when the casing ( 1) pivots in an opposite direction from its new central pivot position. Device according to claim 1 characterized in that , on the one hand, the same element (17) of the junction (3) meshes with the flexible element or elements (6), a play in the meshing affecting a given direction of pivoting of the casing (1) from its central pivot position, making the levels of stopping torque dependent on the directions of pivoting of the casing (1) different, on the other hand, this element (17) is provided with catches ( 19) which allow it to be driven by another element (16) linked to the casing (1), the joining of these elements (16, 17) being able to operate according to two different relative positions and a modification of the position of these elements (16, 17) between them, after having been removed, having the effect that the play which affected a direction of pivoting of the casing (1) from its central pivot position, is transferred to the other direction , thereby reversing the stop torque levels in the same assembly. Device according to either of claims 2 or 3, characterized in that the reversal of the levels of stopping torque, in the same assembly, is implemented by manipulation of the rotary tube (2) already installed which does not require disassembly. Device according to either of Claims 2 and 4, characterized in that the manipulation of the rotary tube (2) comprises a lateral displacement which allows the support elements (8 or 37) to escape from the flexible elements ( 6) of the junction (3), during a rotation generating a displacement of the normally fixed element of the electrical power cut-off device of the engine, the manipulation ending with a lesser rearward rotation, followed of the lateral return of the rotary tube (2) obtained under the effect of a spring (10) which will have been kept compressed during the rotations. Device according to either of Claims 3 and 4, characterized in that the manipulation of the rotary tube (2) comprises a lateral displacement which separates the element (17) which meshes with the flexible elements (6) of the element (16) linked to the casing (1), followed by a rotation which changes the orientation of the meshing element (17) relative to that of the element (16) linked to the casing, followed by a return lateral of the rotary tube (2) obtained under the effect of a spring (10), during which the meshing element (17) reintroduces its cleats (19) in locations of the element (16) linked to the casing ( 1) different from the original ones. Device according to either of Claims 5 or 6, characterized in that the rotational movements, in the manipulation of the rotary tube (2), are surrounded by stops (14). Device according to claim 1 characterized in that the closing of that of the power switches (11), the opening of which caused the engine to stop, is operated for a position of the casing (1) set back from its extreme position of pivot that triggered the stop. Device according to claim 1, characterized in that , the motor turning in the direction which requires the most effort from it, the triggering of the stop is preceded by a reduction in the torque which the flexible element (s) (6) oppose pivoting of the housing (1).

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