Electric actuator for driving a home automation screen

Technical field:

[0001] The invention relates to an electric actuator for driving an automated household curtain, a windshield type, a roller blind, a curtain, a lattice, a projection screen or a garage door. The actuating member according to the invention is provided with a spring brake. This type of brake is particularly suited for tubular motors.

State of the art:

[0002] The use of a helical spring brake in actuators for automated household curtains is known, in particular from patent FR-B-2 610 668. In this document, the helical spring is mounted in the friction part. At least one spring coil is stressed radially through the through hole of the friction part. Each end of the spring forms a grip extending radially to the inside of the spring. Each paw can be moved to drive the rotation of the spring relative to its axis. The input part, the output part and the spring are specially arranged to obtain the following kinematics: the operation of the entrance part located on one side of the first leg drives the rotation of the spring in the first direction. This movement releases the outlet part, i.e. it attempts to reduce the diameter of the outer shell of the spring. In this way, the friction between the through bore of the friction part and the spring coils decreases, which reduces the radial stress between the spring and the friction part. On the contrary, the operation of the outlet part on the opposite side of the first leg drives the rotation of the spring in the second direction, i.e., the opposite direction. This movement blocks the exit part, i.e. it attempts to increase the diameter of the outer shell of the spring. The friction between the through bore of the friction part and the winding of the spring therefore increases. It is the same for radial stress between the spring and the friction part. On the other hand, the entrance part can also act on a second spring paw to drive the spring rotation in the second direction freeing the output part completely. In addition, the outlet part may also act on a second spring paw, to drive the rotation of the spring in the first direction. In this case, the outlet part locks or at least is braked by the friction of the spring against the friction part. Consequently, the rotation of the entrance part allows the spring and the output part to rotate, while rotation of the outlet part locks the spring which blocks the initial movement of the outlet part.

[0003] The basic braking of the outlet part is thus obtained by the friction of the spring against the friction part. The second phenomenon contributing to the braking of the outlet part: It is about the friction of the outlet part at the level of its guiding means. This friction is directly related to the torque applied to the brake. When the motor torque is applied to the inlet part, the inlet part exerts a force on the outlet part via the spring clamp. This force is asymmetric with respect to the axis of the outlet part, it causes a radial force which causes the outlet part to move, until it is supported on its guiding means. This contact inhibits the output part. When the torque is applied to the spring-loaded examples of the outlet part, it exerts a force on the spring paw, attempting to immobilize the rotation of the spring. By reacting to this asymmetric force, the radial force causes the output part to move, until it is supported on its guiding means. In this way, in the classical concept of a spring-loaded brake, there is a secondary braking torque which is added to the braking moment of the main friction of the spring against the friction part. This secondary braking torque occurs during lifting and when lowering the curtain.

[0004] In the patent EP-B-0 976 909, the spring brake comprises an entrance part comprising two teeth, an output part also comprising two teeth, a spring and a friction part. The moment of the motor exerted on the input part is transferred to the outlet part by a tooth slop that rests on one of the spring lugs, which rests on the tooth of the outlet part. The force exerted on the starting part is asymmetrical, it causes the radial force applied to this part, and thus the secondary braking moment. When applying the moment to the outlet part, a phenomenon similar to the one occurring in the brake with FR-B2 610 668 is encountered. The tooth of the outlet part rests on the spring clamp, which locks the spring. By reacting to this asymmetrical force, the radial force causes the starting part to move,

[0005] The mode of operation of the classic brake concepts as described in the previous ones has disadvantages in certain configurations.

Indeed, when the actuator drives the curtain in the downstream direction, i.e. when the load torque exerted by the weight of the curtain at the level of the output part operates in the same direction as the torque of the actuator motor exerted on the level of the entrance part, the addition of a secondary braking torque to the main braking torque is advantageous because the brake response time is reduced, which protects the installation. On the other hand, the existence of a secondary braking torque when the curtain is raised, i.e. when the load torque exerted by the weight of the curtain at the level of the outlet part is opposite to the motor torque of the actuator exerted at the entrance part level, is particularly harmful because the brake brakes continuously, which causes the need for oversizing the engine.

[0006] Patent WO2006059840 A1 describes an electric actuator for driving an automated household curtain according to the preamble of claim 1.

Presentation of the invention:

[0007] The invention proposes an electric actuator equipped with a spring brake to improve the operation of the existing brakes while maintaining their advantages. For optimizing the dimensioning of the motor, the invention aims to eliminate the secondary braking torque when lifting the load. To this end, the invention relates to an electric actuator for driving an automated household curtain that moves between an open position and a closed position, this actuator being provided with a spring brake that includes a helical spring, each end of which forms a radially or axially extending catch. in relation to the central axis of the spring,

- a truncating portion having an approximately cylindrical friction surface against which the radial spring relies, at least one coil,

- an input part driven by an electric motor of the actuator and which may be in contact with at least one of the spring paws, so as to rotate the spring about the center axis of the brake in a direction allowing to reduce the contact force between the helical spring and the surface friction

- an outlet part connected to the curtain and which can be in contact with at least one of the spring paws so as to rotate the spring about the center axis of the brake in a direction allowing to increase the contact force between the coil spring and the friction surface,

In this actuator, when lowering the curtain, the input part drives the spring with a reduction of the contact force, at the point where the output part is released in rotation, without direct contact between the inlet part and the outlet part. According to the invention, the entrance part comprises at least two contact surfaces capable of transmitting the momentum of the motor lifting the screen, by direct contact, with at least two contact surfaces of the respective outlet parts.

[0008] The curtain generates a load moment at the level of the output part that allows the generation of a secondary braking torque. Consequently, this actuator is particularly adapted for vertical displacement curtains whose weight makes it possible to generate the aforementioned load moment. It may be the winding of the curtain around the pipe or the tilting of the garage door between the horizontal position and the vertical position.

[0009] The entrance part and the exit part are in direct contact only when the curtain is raised. In this way, during lowering, these two parts do not contact directly for motor torque transfer. Indeed, during this maneuver, the entrance part releases the brake by acting only on one of the spring lugs. The torque of the motor is exerted on this paw. There is no force transferred between the inlet part and the outlet part. The outlet part is held by the other spring clip. For this reason, it exerts a force, generated by the moment of loading, only on the gripper, in such a way as to rotate the spring about the center axis of the brake in a direction allowing to increase the contact force between the helical spring and the friction surface.

In this description, the direct contact between two parts means that one part acts on the other, either by direct cooperation of complementary surfaces, or by cooperation between complementary surfaces via a second rigid portion between these surfaces, or in a mixed manner comprising previously mentioned types of cooperation. The direct contact may be obtained by one or more contact surfaces provided on the outlet part, one such contact surface being the surface on which the complementary contact surface of the input part rests or the complementary surface of the intermediate part on which the entrance part operates. For implementing the invention, it is necessary that the moment is transferred by at least two contact surfaces of the outlet part.

[0011] Balancing the torque of the motor to reduce the secondary braking torque when lifting can cleverly be made by transferring the torque of the motor through several sets of contact surfaces positioned relative to the axis of rotation of the spring in such a way that the torque of the motor is transferred in a somewhat balanced way, making the outlet part is not tightened radially. Indeed, these sets of surfaces can be placed around the axis of the outlet part in such a way as to reduce or eliminate the resulting radial force. For example, the torque can be transferred through two contact surfaces of the outlet part that are approximately identical and diametrically opposed to the axis of the outlet part. This solution is easy to implement.

[0012] Preferably, the operation of the brake is identical regardless of the direction of the motor torque for lifting the screen. This characteristic makes it possible to obtain a universal actuator that can be installed independently of the configuration of the curtain. For example, for a tubular actuator entering a coiling tube, the operation of the actuator is identical when winding in a given direction or in the opposite direction. This symmetrical operation of the brake makes it possible to rationally select the range and simplify the installation of the actuator, because it is not necessary to distinguish whether the motor should be mounted in a manner specified in relation to the curtain. [0013] According to other aspects of the preferred but not binding invention:

- In the absence of engine torque, the output part exerts a force on the spring paw in such a way as to rotate the spring about the center axis of the brake in a direction allowing to increase the contact force between the spring and the friction surface.

- At the level of at least one contact surface, the direct contact between the inlet part and the outlet part is realized by means of a rigid part, such as one of the spring paws.

- The arrangement of the contact surface allows balancing the transfer of the lifting moment of the motor, in such a way as to eliminate or reduce the radial component, in relation to the axis of rotation of the spring, of forces transmitted to the outlet part.

- The two contact surfaces of the output part are diametrically opposed in the output.

It is possible to provide a means of contacting the ratio to the axis of the part that the outlet part is a part having a kinematics different from the kinematics of the outlet part, in particular a part connected to a friction part or an entrance part when the radial force exerts on the outlet part, this force radial is generated only when lowering the curtain.

[0015] The outlet part is preferably able to abut against the centering member of the outlet part in relation to the entrance part under the effect of the radial component of the moment of loading through the curtain when lowering the screen.

[0016] It can further be provided that the outlet part is pivotable with respect to the entrance part. The inlet part and the outlet part should actually be centered one in relation to the other. The inlet part and the outlet part can be centered by a shaft passing through these parts. The shaft is mounted clamped in the inlet or outlet part and is slidably mounted in the second part of the outlet part or the entrance part, respectively. This centering is simple to implement and compact. This subassembly consisting of the entrance part and the outlet part is then preferably centered with respect to the friction part. This centering can be performed either through the outlet part or through the entrance part. Preferably, the subassembly is centered by the entrance part,

Description of drawings:

[0017] The invention will be better understood by reading the following description, presented only by way of example and made with reference to the accompanying drawings, in which:

- figure 1 is a simplified illustration of the architecture of a tubular actuating member according to the invention comprising a spring brake according to the invention;

- figure 2 is an exploded perspective view of a spring brake belonging to the actuator of figure 1;

- figure 3 is a simplified cross-sectional illustration of the operation of the spring brake of figure 2 when lifting the load;

- figure 4 is a simplified cross-sectional illustration of the operation of the spring brake of figure 2 when lowering the load;

- figure 5 is a simplified cross-sectional illustration of the prior art spring-brake operation during load lifting;

- figure 6 is a exploded perspective view of a second embodiment of a spring brake that may belong to the actuator of figure 1;

- figure 7 is a perspective view of the components of the spring-loaded brake of figure 6 arranged at an angle;

- figure 8 is a simplified illustration, in the end view in the direction of the arrow F of figure 6 with a partial cross-sectional view of the spring-brake function of figure 6 when lifting the torque-generating load in the clockwise direction on the output part of the brake;

- figure 9 is a simplified illustration analogous to figure 8, end view with a partial cross-section of the spring-loaded brake operation of figure 6 when lowering the torque load in the clockwise direction on the output part of the brake;

- figure 10 is a simplified illustration analogous to figure 8, end view with a partial cross-section, of the spring-brake function of figure 6 when lifting the torque-generating load in an anti-clockwise direction on the output part of the brake;

- figure 11 is a simplified illustration analogous to figure 8, end view with a partial cross-section, of the spring-brake function of figure 6 when lowering the torque-generating load in the counterclockwise direction on the output part of the brake;

Description of the embodiments:

[0018] Figure 1 schematically illustrates a rotary tubular actuating member 100 for driving a rotating winding tube 1 on which a curtain 2 closing the orifice O can be wound to a greater or lesser extent. The tube 1 is driven by the actuator 100 rotationally about the rotation axis XX which is placed horizontally in the upper part of the hole. The hole O is, for example, an opening placed in the walls of the building. The actuator 100, pipe 1 and curtain 2 then form a mechanized roll-up roller shutter.

The actuator 100 comprises a cylindrical tube 101, in which a gearmotor 102 comprising an electric motor 103, a first reduction stage 104, a spring brake 105, a second reduction stage 106 and an output shaft 107 that projects from the end 101A of the tube 101 and drives a crown wheel 3 rotatably connected to the pipe 1.

[0020] The winding tube 1 rotates about an axis XX and a fixed tube 101 thanks to two rotatable connections. One annular bearing 4, mounted on the outer circumference of the pipe 101 near its end 101B opposite to the end 101 A, provides the first rotary connection. A second rotary connection is installed at the other end of the pipe 1 and is not shown.

[0021] The actuator 100 also includes a mounting portion 109 protruding from the end 101B and allowing the actuator 100 to be fastened to the frame 5. This fixing part 109 is further intended for closing the pipe 101 as well as for supporting the motor control module 108 103. This control module is powered by the mains power cable 6.

During operation of the tubular actuator 100, the gearmotor 102 rotates the shaft 107, which in turn drives the tube 1 via the crown wheel 3. For example, when the actuator 100 is installed in the roller shutter housing, the rotation of the shaft 103 drives the opening and alternately, closing the opening O. The curtain 2 thus moves vertically in the opening O, between the upper opening position and the lower position of the closure.

[0023] Figures 2 to 4 illustrate more specifically the structure of the spring-loaded brake 105 according to the first embodiment of the invention. As shown in FIG. 1, the motor rotor 103 rotatably drives the first reduction stage gear box 104. The planetary gear barrel 110, which supports the three planet gears, also forms an input portion of the brake 105. This brake 105 includes a helical spring 130 whose coils are centered on the axle. X130 coincident with the axis XX when the brake 105 is positioned as shown in figure 1. This spring is mounted compressed inside the through hole 141 of the friction part 140. In other words, the outer shell 131 of the spring 130, which is defined by the external coils forming it, rests for the radial surface of the "teeth" 111a of the screw 130 through hole 141,

[0024] Each end of the spring 130 forms a grip 132a, 132b extending radially from its turns to the axis X130 and into the interior of the spring.

[0025] The input part 110 comprises two protrusions or and 111b extending inside the spring. Each projection 111a or 111b comprises a surface 113a or 113b that may contact respectively with the surface 133a of the first leg 132a forming the first end of the spring or with the surface

133b of the second lug 132b forming the other end of the spring. The surface 133a is arranged in such a way that the action on it drives the rotation of the spring about the axis X130 in the direction opposite to the direction of rotation of the spring if the action is exerted on the surface 133b.

which itself is coincident with the axis XX in the configuration of the assembled actuator 100 shown in figure 1. The direction or dimension is called "axial" when it extends or is measured parallel to the axis X105. The direction is called radial, when it is perpendicular and intersecting the X105 axis.

Opposite the entrance part 110 there is an exit part 120 of the brake 105. It comprises two lugs 121a, 121c also entering into the helical spring 130. The ear 121a is provided with two notches or empty slots 122a, 122b provided on both sides of the same. ear. Each notch 122a or 122b is intended to receive one of the spring paws 132a, 132b and is limited partially by the surfaces 124a, 124b that may contact the finger surface 132a, 134b 132a, 132b. Surfaces 134a and 134b are respectively opposite to surfaces 133a and 133b.

Operation on one of the surfaces 134a, 134b attempts to extend the legs 132a and 132b, resulting in radial enlargement of the turns of the spring 130 relative to the axis X130 and increasing the contact force between the spring 130 and the friction surface of the through hole 141. This results in the brake action that is, blocking or firmly braking the rotation of the spring 130 relative to the portion 140. In this way, the radial stress between the outer sheath 131 of the helical spring and the friction surface 141 increases, which immobilizes or strongly brakes the portion 120 about the X105 and X130 axes.

For the brake to work, it is necessary to have an angular clearance between the teeth 111a and 111b of the inlet portion 110 and the spring paws 132a and 132b. Likewise, an angular clearance between the eye 121a and the spring paws 132a and 132b is also needed. Ear width 121 is provided for this purpose. Furthermore, the axial length L111 or L121 of portions 111a, 111b and 121a is slightly greater than the axial length L130 of the spring.

[0030] The outlet part 120 also comprises a toothing 129 forming a coupling with the second reducing stage 106.

The centering of the outlet part 120 in relation to the inlet part 110 is effected by a shaft 118 projecting axially with respect to the entrance part, from the side of the outlet part 120. This shaft 118 serves as a guiding means for the outlet part thanks to a through hole 128 made in its middle.

[0032] As can be seen more clearly from figures 3 to 4, the load L formed by the cover 2 can be treated as connected to the outlet part 120 by means 1, 3, 106 and 107, as shown by the vertical broken line in figures 3 to 4. .

[0033] The load weight L exerts on the output portion 120 a moment CL attempting to rotate it about the axis X105, clockwise in figures 3 and 4.

[0034] Attention is drawn to X120 the central axis of the outlet part 120 which is coincident with the axis X105 in the assembled configuration of the brake.

[0035] During the lifting of the load L i as shown schematically in figure 3, the rotation in the clockwise direction in figure 3 of the output part 120, the rotation which is normally caused by the torque CL is blocked by the entrance part 110. Input part 110 it is rotatably driven in the counterclockwise direction of figure 3 by the torque CM generated by the motor and balanced by the efficiency of the first reduction stage 104. The two projections 111a and 111b of the inlet portion 110 rotate about the X105 and XX axis of the concurrent ones until one of the protrusions 111a or 111b will be in contact with the surface 123a or 123b of the ear 121a of the outlet part. At this point, the second projection 111b or 111a also begins to contact one of surfaces 123c or 123d of the second ear 121c of the outlet part. Consequently, the torque of the CM motor is transferred to the outlet part via two sets of contact surfaces formed between surfaces 113a and 113d and surfaces 123a and 123d diametrically opposed to the X105 axis and to the X120 axis of the outlet part, which consequently reduces or eliminates the radial component from the resulting torque CM on the output part 120. The motor torque CM is in the opposite direction to the load CL. The surfaces 123a and 123d are the contact surfaces of the outlet part 120. which in effect reduces or eliminates the radial component from the resulting torque CM exerted on the output part 120. The torque of the CM motor is in the opposite direction to the load moment CL. The surfaces 123a and 123d are the contact surfaces of the outlet part 120. which in effect reduces or eliminates the radial component from the resulting torque CM exerted on the output part 120. The torque of the CM motor is in the opposite direction to the load moment CL. The surfaces 123a and 123d are the contact surfaces of the outlet part 120.

[0036] The force balance of the output part 120 is shown in figure 3. The load torque CL is balanced by the forces F1a and F1b resulting respectively from the abutment between the surface 113a of the tooth 111a and the surface 123a of the ear 121a and from the abutment between the surface 113d of the tooth 111b and the surface 123d ucha 121c. These two forces F1a and F1b define in the force category the motor torque CM necessary to overcome the load torque CL. The two forces F1a and F1b have approximately the same intensity and are approximately symmetrical with respect to the central axis X120 of the outlet part, the radial component of the resulting moment CM on the outlet part 120 is negligible and even zero. It is noted that the shaft 118 of the entrance part allowing the outlet part to center does not come into contact with the through hole 128 of the outlet part in this configuration,

[0037] For lifting the load, the torque CM should be greater than the sum of the load torque CL and the moment of resistance of the brake spring due to residual friction between the outer shell 131 and the friction surface 141. At start-up, the applied torque CM should be larger because Releasing the brake 105, you must overcome the static friction force. In this way, the projection 111a acts on one of the spring lugs, in a given case a grip 132a, placed in the notch 122a, when the lug 121a is rotatably driven.

[0038] When lowering the load L i as shown schematically in figure 4, the rotation of the output part in the clockwise direction in this figure is not stopped by the entrance part but by the spring 130. In this way, the load moment CL is pressed down. an ear 121a to one of the legs 132a or 132b, in the present case item 132a. This results in a radial enlargement of the turns of the spring 130 and actuation of the brake 105, as explained previously. The torque CL exerted by the ear 121a on the surface 134a of the leg 132a is balanced by the efficiency of the second reduction stage 106. The leg 132a is inserted into the seat 122a. The motor torque CM has the same direction as the load torque CL.

[0039] The balance of forces of the output part is shown in figure 4. The load moment CL is balanced by the two forces F2a and F2b. The first force F2a corresponds to the reaction of the surface 134a of the leg 132a of the spring 130 on the abutment surface 124a of the notch 122a. Because this first force F2a does not allow complete compensation of the load moment CL, the output part 120 attempts to move perpendicular to the axis X105, relative to the previous back configuration, until the outlet part contacts the guide means formed by the shaft 118, which it is connected to the inlet part 110. The through hole 128 of the outlet part of the outlet contacts this way with the shaft 118, thus generating a second radial force F2b to balance the load moment CL. This second force F2b creates friction during the load lowering movement. This friction inhibits the load and adds to the braking moment of the spring. It therefore has a part in the reactivity of the brake. His response time is faster than the brake response time, which would not have this friction.

[0040] It is noted that, for this embodiment, the inlet part 110 is itself centered with respect to the friction part 140 due to the cylindrical shell whose surface of the shell, not shown, cooperates with the through hole 141 of the friction part. Consequently, the previous strength

2b induces an equivalent force, not shown, between the input part 110 and the grip portion 140. This equivalent force participates in the formation of a secondary braking torque and contributes to the reactivity of the brake.

[0041] In order to be able to lower the load, the brake must be released. To this end, the torque of the CM motor rotatably drives the projections 111a and 111b of the inlet portion 110 until the protrusion 111b abuts the surface 133b of the leg 132b of the spring 130. By this action, the spring 130 is expanded and the outlet part 120 can rotate due to the torque CL loads. Parts 110 and 120 do not come in direct contact then.

[0042] If the winding direction of the load is opposite, the operation is identical. The brake operation is therefore symmetrical, which facilitates its installation, because the brake parameters are the same, regardless of the direction of assembly of the actuator, i.e. the direction of the motor torque CM, which is used to lift the curtain 2.

[0043] Figure 5 shows the classic of the prior art, the lifting behavior of the spring brake and its more exactly

The parts of the brake depicted in figure 5, which are analogous to the same designations. For this type of brake, the brake parts 105 have a referral reduced by 100 the output part is not provided for balancing the load moment when lifting. The exit part 20 comprises only one ear 21a. During lifting, the action is similar to the action of the brake 105 in the configuration of figure 3. The moment of the motor CM drives the projection 11a to rotate until it contacts the surface 33a of the spring 32a of the spring 30. The counter surface 34a, for its part, is based on the surface 23a of the ear 21a of the outlet part 20 due to the load torque CL. Consequently, the torque of the CM motor is transferred to the outlet part 20 via the clamp 32a of the spring 30.

In the embodiment of the invention described previously with reference to figures 1 to 4, the motor torque is transferred directly to the output part 120 by contact between the surface 113a of the entrance part 110 and the surface 123a of the outlet part 120, the spring paw is then hidden in the seat 122a provided For this purpose. This allows better torque transfer and less part load.

that during lifting, the output part 20 has a relative speed relative to the friction part 40, this force F'1b generates friction during the load lifting movement. To increase the load L, the motor torque CM should therefore be greater than the sum of the load torque CL, this friction, and at the start, the torque necessary to release the brake. Consequently, this friction is disadvantageous for the dimensioning of the motor, because it should be stronger so that it can compensate for the additional friction arising from the force F'1b. the torque necessary to release the brake. Consequently, this friction is disadvantageous for the dimensioning of the motor, because it should be stronger so that it can compensate for the additional friction arising from the force F'1b. the torque necessary to release the brake. Consequently, this friction is disadvantageous for the dimensioning of the motor, because it should be stronger so that it can compensate for the additional friction arising from the force F'1b.

[0046] For lowering the load, the operation is analogous to that shown in figure 3 for the brake according to the invention. The balance of forces is, on the other hand, more similar to the equilibrium shown in FIG. 5. The load is inhibited by the braking moment of the spring 30 and the friction with the guiding means formed by the through hole 41 of the outlet part.

[0047] Figures 4 and 5 show two different means for guiding the exit part 20 or 120. In the first case, the outlet part 120 is guided with respect to the entrance part 110. The entrance part 110 is, moreover, centered with respect to the friction part 140. In the second case, the outlet part 20 is guided relative to the friction part 40 which is constant. Trials have shown that the brake 105 behaves better in the first case. In fact, the centering of the outlet part relative to the entrance part makes it possible to reduce the vibration of the brake.

[0048] Figures 6 to 11 illustrate a second embodiment of the brake. The principle of operation is similar to the first embodiment. The reference numerals of these parts are the same as the corresponding reference numerals in the first embodiment increased by 100.

The output of the first reduction reduction gear 104 rotatably drives the portion 210 forming the brake input 105. The inlet portion 210 is provided with a polygon shaft 219 for receiving and transferring a torque from the reduction stage 104. The brake 105 includes a helical spring 230 whose turns are centered on the X230 axis concurrent with the axis XX when the brake 105 is in place as shown in figure 1. The axes X230 and XX are coincident with the central axis X105 of the brake 105 in the configuration of the assembled actuator 100 comprising the brake 105 of this second embodiment.

The spring 230 is mounted compressed inside the through hole 241 of the friction part 240. In other words, the outer shell 231 of the spring 230, which is defined by the outer coils forming it, abuts the radial surface of the through hole 241, which attempts to connect by friction, spring 230 and part 240.

[0051] Each end of the spring 230 forms a leg 232a, 232b extending radially to the axis X230 and into the interior of the spring, from its coils.

[0052] The entrance part 210 comprises a protrusion or "tooth" 211a entering into the helical spring 230 between the pawls 232a and 232b. This tooth 211a has two surfaces 213a, 213b that can respectively contact the surfaces 233a of the first leg 232a forming the first end of the spring and the surface 233b of the second leg 232b forming the other end of the spring. The surface 233a is arranged in such a way that the action on it drives the rotation of the spring about the axis X230 in the direction opposite to the direction of rotation of the spring, if the action is exerted on the surface 233b.

[0053] Operation through tooth 211a on surface 233a or 233b attempts to release the brake, i.e., to pivotally rotate the gripper 232a or 232b about the axis X230 and X105 in a direction such that the radial stress between the outer shell 231 of the spring 230 and the friction surface of the through hole 241 is reduced.

Indeed, the action of the tooth 211a on one of the surfaces 233a or 233b attempts to compress radially the spring 230 about the axis XX, so that its outer shell moves away from the surface of the through hole 241. The portion 210 thus allows action on the spring 230 to reduce the contact force between the spring and the spring. the friction surface of the through hole 241. Opposite the entrance portion 210 is the exit portion 220 of the brake 105. It includes two lugs 221a, 221b also entering the helical spring 230. Each ear is respectively provided with a blank notch or slot 222a, 222b intended for receiving one of the paws 232a, 232b of the spring 230. Each cutout 222a, 222b is limited in part by the surface 224a, 224b that may be in contact with each other.with the surfaces 234a, 234b of the tabs 232a, 232b. Surfaces 234a and 234b are respectively opposite to surfaces 233a and 233b.

Operation on one of the surfaces 234a, 234b attempts to approach the legs 232a and 232b, which has the effect of radially enlarging the turns of the spring 230 relative to the axis X230 and increases the contact force between the outer shell 231 of the spring 230 and the friction surface of the through hole 241 This causes the brake to function, i.e. blocking or strong braking of the rotation of the spring 230 relative to the portion 240. In this way, the radial stress between the outer sheath 231 of the helical spring and the friction surface 241 increases.

Furthermore, each ear 221a, 221b of the outlet portion 220 includes a protruding portion 226a, 226b extending axially toward the entrance portion and that can seat respectively in the banana-shaped opening 2106c, 216d, of the inlet portion 210 when the brake 105 is connected. These protruding portions 226a and 226b are dimensioned and arranged so that one of their faces 227a, 227b contacts the inner surface 217c, 217d delimiting the corresponding opening 216c, 216d when the surface 213b, 213a of the tooth 211a of the entrance portion 210 is in contact with the surface 223b, 223a of the ear 221b, 221a of the outlet part 220.

[0057] Figures 8 and 10 illustrate two possible configurations of the brake 105. The dimensioning of the holes 216c, 216d is such that, in addition to the two previous configurations, the protruding parts 226a, 226b do not abut against the inner surface of the opening.

In order for the brake to work, it is necessary to have an angular clearance between the tooth 211a of the inlet portion 210 and the spring paws 232a and 232b. Likewise, an angular play between the ear 221a and 221b and the spring paws 232a and 232b is also needed. The tooth width 211a is provided for this purpose. Furthermore, the axial length L211 and L221 of parts 211a, 221a and 221b is slightly greater than the axial length L230 of the spring.

[0059] The centering of the outlet portion 220 relative to the inlet portion 210 is required by the shaft 270. This shaft is equipped with a centered through hole 218 of the inlet portion 210. A portion of the shaft 270 projects from the side of the outlet portion 220.

[0060] Figures 8 to 11 illustrate the operation of the brake 105. Figures 8 and 9 correspond to winding the curtain on the shaft 1 in the clockwise direction in these figures. Figure 8 illustrates load lifting, while figure 9 illustrates the lowering thereof. Figures 10 and 11 correspond to winding the curtain on shaft 1 in an anti-clockwise direction in these figures. Figure 10 shows the load lifting, while Figure 11 shows the lowering.

[0061] In the first phase, the operation of the brake is explained in relation to the first configuration of the winding of the curtain, i.e. winding in a clockwise direction in figures 8 and 9.

[0062] By default, the weight of the load L exerts on the moment 220 a torque CL which presses one of the ears 221a or 221b, if applicable, the ear 221b, to one of the legs 232a or 232b, in the case of the paw 232b, as shown in figure 9. As a result, the coils of the spring 230 are radially enlarged and the brake 105, as explained previously, is activated. The torque CL exerted by the ear 221b on the surface 234b of the pin 232b is balanced by the efficiency of the second reduction stage 106. This moment is represented by the vector associated with the ear 221b. The pad 232b is then inserted into the seat 224b.

[0063] When lifting the load L i as shown in figure 8, the input part 210 is rotatably driven by the torque CM generated by the motor and balanced by the efficiency of the first reduction stage 104. The protrusion 211 a of the entrance part rotates until it contacts with the ear 221b of the outlet part, in engagement between surfaces 213b and 223b. For lifting the load, the torque CM should be greater than the sum of the torque CL and the moment of resistance of the brake spring resulting from the residual friction between the outer shell of the spring and the friction surface of the through hole 241.

The CM moment is presented in the form of a vector drawn with a dashed line associated with the entrance part.

[0064] At start-up, the applied torque CM should be larger, because to release the brake 105, the static friction force has to be overcome. For releasing the brake

105, protrusion 211a acts on the paw 232b located in the notch 222b when the ear 221b is rotatably driven. The transfer of motor torque CM from the input part 210 to the output part 220 is realized by a double contact. On the one hand, the surface 213b of the projection 211a rests on the surface 223b of the ear 221b. And, diametrically opposite, the inner surface 217c of the hole 216c rests on the surface 227a of the protruding portion 226a. In this way, the load moment CL is balanced by the forces F1a and F1b resulting from the support between the parts 211a and 221b, on the one hand, 216c and 226a, on the other hand. These two forces have approximately the same intensity and are approximately symmetric with respect to the central axis X105 of the brake 105 and the axis X220 of the outlet part, the resulting radial component of the torque CM at the outlet part being negligible, and even zero. Surfaces 223b and 227a are the contact surfaces of the outlet part.

[0065] When lowering the load L i as shown schematically in figure 9, the rotation of the outlet part 220 is not stopped by the entrance part 210 but by the spring 230. In this way, the load moment CL presses the ear 221b to one of the legs 232a or 232b , in case of the case 232b. This results in a radial enlargement of the turns of the spring 230 and actuation of the brake 105, as explained previously.

[0066] The torque CL exerted by the ear 221b on the surface 234b of the leg 232b is balanced by the efficiency of the second reduction stage 106. The leg 232b is inserted into the seat 222b. The motor torque CM has the same direction as the load torque CL.

The balance of forces is then different than the balance of forces during lifting. The load torque CL is balanced by the forces F2a and F2b. The first force F2a corresponds to the reaction of the load-locking spring at the level of engagement between the surface 234b of the spring 232b of the spring 230 and the abutment surface 224b of the mouth 222b of the ear 221b of the outlet part. Since this first force F2a does not enable the load moment CL to be compensated, the output part 220 attempts to rotate relative to the previous back configuration until the outlet part contacts the guide means formed by the shaft 270 connected to the entrance part 210. Opening The through-run 228 leading the output portion 220 relative to the shaft 270 is in this way contacted with the shaft 270, thereby generating a second force F2b to balance the load moment CL. This force is radial in relation to the X220 axis. This force F2b creates friction during the movement of load L when lowering. This friction inhibits the load and adds to the braking moment of the spring. It therefore has a part in the reactivity of the brake. His response time is faster than the brake response time, which would not have this friction.

[0067] It is noted that for this embodiment, the inlet portion 210 is itself centered with respect to the friction part 240 by a cylindrical shell whose shell surface, not shown, cooperates with the through hole 241 of the friction part. Consequently, the previous force F2b then evokes an equivalent force, not shown, between the entrance portion 210 and the grating portion 240. This equivalent force participates in the formation of a secondary braking torque and contributes to the reactivity of the brake.

[0068] In order to be able to lower the load, the brake must be released. For this purpose, the torque of the CM motor rotatably drives the projection 211a of the inlet portion until it abuts on the surface 233a of the spring 232a of the spring 230. By this action, the spring 230 is expanded and the outlet part 220 can rotate due to the load moment CL, parts 210 and 220 are not in direct contact then.

[0069] The operation of the brake in the second winding configuration is illustrated in figures 10 and 11.

[0070] When lifted and as illustrated in Figure 10, the load torque CL is balanced by the forces F1a and F1b arising from one side, as a result of contact between the surface 213a of the tooth 211a and the surface 223a of the ear 221a and the other, as a result of contact between the inner surface 217d of the opening 216d and surface 227b of the protruding portion 226b. These forces F1a and F2a are balanced, the resulting radial torque component CM on the output part 220 is negligible. The motor should therefore provide a motor torque greater than the load moment CL, to which only the moment of brake resistance is added, which results from the friction between the spring 230 and the friction part 240. There is or there is a small secondary braking torque generated by the friction between the output part 220 and its guide shaft 270.

[0071] During lowering, the load torque CL is balanced by the forces F2a and F2b. The first force F2a corresponds to the reaction of the spring 230 blocking the load L at the coupling level between the surface 234a of the spring 232a of the spring 230 and the abutment surface 224a of the cut 222a of the ear 221a. The second force F2b corresponds to the force placed at the level of the guide shaft 270 of the output portion 220, while the portions 210 and 220 do not come in direct contact. This friction generates a radial force that inhibits the load. In this way, the brake reacts quickly because the secondary braking torque is no longer negligible.

[0072] Two embodiments describe a brake spring whose ends are bent inside the spring. Of course, these ends can be bent outside. Another variation consists in bending the ends parallel to the center axis of the spring. These feet then extend axially from one side of the spring, extending the center of the spring.

[0073] Furthermore, the spring brake should not especially be positioned between the two reducing stages. It can be placed on the output of the motor or on the output of the reducer.

Somfy SAS

Proxy:

81P30154PL00

EP 2 267 330 B1