EP0750092B1 - Roll-up device for venetian blinds - Google Patents

Description

The present invention relates to a device for winding cords or Venetian blind ribbons or pleated comprising, housed in a box, a motor electric equipped with a brake, a reducer, at least one output shaft driving two winding drums on which the cords are wound, respectively blind ribbons, automatic shutdown means when the blind is fully rolled up, means automatic shutdown when the blind has reached a state of the desired sequence, means for detecting a engine blocking causing the engine to stop when detection of such a blockage and adjustment means from the bottom breakpoint corresponding to the state of desired course.

Document DE 33 02 529, we know a device for winding ribbons for a Venetian blind equipped with a tubular gear motor whose automatic stop is provided by a lap counting device comprising two screws driven by the motor and bearing each a sliding nut in the form of toothed wheels in taken with a grooved tree which immobilizes them in rotation, each of these sliding nuts actuating a switch after a certain movement, actuation of these switches ensuring the stopping of the motor, respectively in the rolled up position and in unrolled position of the blind. Setting the breakpoint is done by manually driving the splined shaft, which has the effect of moving the sliding nuts the along their screw. Despite the adjustment possibilities offered by these winding devices, these have the disadvantage of not taking into account humidity conditions at the time of installation and variations of these conditions, which cause variations in cord length, respectively ribbons, nor variations in length due to wear. If the humidity is low, the cords elongate and this elongation, combined with the structural evolutions of the installation, has for result of changes in positions Stop highs appear. In the event that several blinds are arranged side by side on a facade building, for example, not all blinds are fully raised to the high stop position because the breakpoints are different from each other, this which is particularly unsightly. If the rate humidity is important, rather a reduction in the length of the cords, the consequence is a mechanical stop by stop of the package blades against the front installation box electroanic shutdown. The engine then remains under voltage, at the rate of the thermal safety cycle, and deteriorates quickly. In addition, adjusting the breakpoints are done by mechanical relatively complicated and fragile.

Document DE 1,763,272 discloses a device of roller blinds for venetian blinds high is ensured by an actuated switch directly through the blind when it is completely coiled and whose bottom breakpoint is determined by a lap counting device comprising a single screw on which a sliding nut moves actuating a switch. No means are planned for adjusting the breakpoint in the fully positioned position rolled out of the blind (bottom point). For this purpose, it would be necessary either to drive the screw of the device lap counting, which would require means of clutch, between the screw and the motor, or to move the switch, which would require mounting the switch on a screw. The use of a switch for stopping at high point requires in addition to pulling wires between the switch and the engine.

We also know winding devices blinds in which the rolling element stops is ensured by the detection of a drop in speed of displacement of the windable element (EP 0 533 625, EP 0 573 388). Such devices require means of relatively expensive detection and electronics.

We also know various devices detecting the braking or blocking of an engine by detection an overcurrent (JP 42 50 286, DE 42 44 378), the detection of a speed variation (DE 44 01 463) or a voltage drop on the auxiliary phase of an asynchronous motor (DE 43 12 987) or across the phase shift capacitor (EP 0 551 053).

We finally know Venetian blinds with drive manual in which part of the tree drive consists of a screw carrying a sliding nut moving between two stops made up of nuts mounted and locked on the same screw. The position of one of these nuts determines the position fully extended from the awning, position in which the sliding nut abuts against this stop. According to the mounting direction of the device, one or other of the stop nut is used as a stopper in unrolled position. To perform stitch adjustment shutdown of the blind in the unrolled position (low point), the sliding nut is brought into abutment against the abutment determining the low point and the blind deployed and then hooked. There is no way to modify later this setting and this is very annoying. he is indeed very difficult to fix a deployed blind exactly at the desired unrolled position. In addition, at use, especially in the early stages of use, the elements being put in place, it appears changes in the actual stop position. For modify the setting, it is then necessary to access with the stop nut and, for this, the box in which the device is mounted winding.

The object of the present invention is to provide a device winding comprising means for stopping the blind in mechanically simple high and low positions ensuring, in all circumstances, a recovery complete of the blind and allowing, by simple means, an adjustment of the setting of the blind bottom breakpoint.

The winding device according to the invention is characterized in that the means for stopping the blind in the desired unwinding position are made up a screw mounted coaxially and integral in rotation with said output shaft in a cylindrical cage immobilized in rotation in the box by means manually operable lock and nut player mounted on the screw and immobilized in rotation in said cage, stopping the engine in position completely rolled up of the blind being provided by the abutment of the blind against the box and the motor blockage detection and blind shutdown at low point being ensured by the abutment of the nut player against a fixed stop fixed to the cage and detecting an engine blockage, adjusting the low stopping point made by unlocking said cage and its rotation drive.

The engine can be stopped by detecting its blockage. do by any means of detection or analysis of a variation of an electrical quantity linked to blocking mechanics of the motor rotor, in particular by one of the devices described in the documents cited more high.

The cage locking means can be consisting, for example, of a simple screw, preferably a needle screw, or a gear screw meshing with helical teeth formed on the around the cage. In the second case, the screw allows also to train the cage in rotation for the low breakpoint adjustment.

The accompanying drawing shows, by way of example, a embodiment of the invention.

The only figure in the drawing is a partial view in axial section of a winding device mounted in a box.

In a box 1 of rectangular section are mounted a gear motor 2 having two output shafts opposite 3 and 5 and a revolution counting device 5. The counting device 5 comprises a screw 6 extending the output axis 4 and integral, by a pin 18, in rotation of this axis and a nut portable player 7 immobilized in rotation in a groove longitudinal 8 provided in the inner wall of a cage 9 in the form of a cylindrical pot mounted in a cradle 10 secured to the housing 1. The end of the screw 6 opposite to the gear motor 2 is secured in rotation, by a pin 19, of a shaft 11 carrying a first winding cone 12 on which comes wind a first cord 13 of a blind not represented. On the other side, the shaft 3 carries a second winding cone 14 on which is wound a second cord 15. Winding cones 13 and 15 are, for example, winding cones such as described in document EP 0 554 212. The cage 9 is provided, on at least part of its circumference, a helical toothing 16 meshing with a screw transverse 17 rotating in cradle 10, immobilized in translation in this cradle and accessible from the outside of the box 1. The cage 9 is therefore immobilized in rotation by the screw 17, but it can turn in its cradle during the training of the screw 17 in rotation. The engine is also equipped with a brake, for example an electromagnetic brake operating by lack of supply current and means of detection of an engine blockage detecting, by example, overconsumption causing the cut of said motor and brake supply when a over consumption of current is detected. These means of detection can be achieved, for example, as described above in one of the documents cited more high. Instead of an electromagnetic brake, the motor could be fitted with a mechanical device brake non-return.

The operation of this device is as follows:

When installing the awning, the sliding nut 7 is brought into abutment against the bottom of its cage 9, that is to say on the side of the shaft 11. The blind is then hung in its unrolled position. To perfect the low breakpoint so as to allow a little more unwinding, we act on screw 17. The motor being at the stop is kept blocked by its brake, the screw 6 is immobilized, so that the rotational drive of the cage 9 allows the sliding nut 7 to be moved away from the bottom from the cage. The motor is then reactivated and the blind unrolls until the sliding nut 7 comes to a stop against the bottom of the cage 9. The engine is then blocked, overcurrent consumption is detected and the power supply to the motor and its brake is cut off. By successive approaches, we perfect the adjustment.

If, at the start, the blind is not rolled out enough, we start by rewinding it slightly by activating the motor in the winding direction so that bring the blind to a slightly higher position at the desired low stop position. With the engine at the stop, the cage 9 is rotated by means of the screw 17 so as to bring the sliding nut 7 into abutment against the bottom of the cage. We then find ourselves in the previous situation in which the blind is less proceed as desired and the adjustment is carried out as previously.

The shutter stop in the fully rolled up position is ensured by the coming into abutment of the blade pack of the blind against box 1, which has the effect of strongly brake the engine, the means of detection detect overcurrent consumption, this which has the effect of cutting off the power to the motor.

According to an alternative embodiment, the screw 17 is replaced by a simple radial screw, preferably a screw needle. In this case, the low breakpoint setting, so as to get a little more unwinding, can be executed in another way. The needle screw being loose, the engine is started. Although the nut player 7 is in abutment against the bottom of the cage 9, the screw 6 can rotate by driving the cage 9. When the desired stop position is reached, we cut power to the engine and block cage 9 at using the needle screw.

To get less progress, we start with wind the cords by means of the motor so that bring the blind to a slightly higher position at the desired low stop position, as before.

In this variant with a needle screw, the cage 9 unlocked could be manually rotated at through a cutout provided in the box. The training could be direct or by through a thumb wheel.

The pot-shaped cage 9 also constitutes a casing dustproof that protects screw 6 and its nut music player. It has indeed occurred, in known devices, that dust disturbs the operation of the automatic stop device.

Claims (4)

1. A device for rolling up cords or tapes of a Venetian or folded blind comprising, housed in a casing (1), an electric motor (2) equipped with a brake, a reduction gear, at least one output shaft (3, 4) driving two roll-up drums (12, 14) over which the cords (13, 15) or the tapes of the blind are wound, means for automatically stopping when the blind is completely rolled up, means for automatically stopping when the blind has reached a desired state of unrolling, means for detecting a blockage of the motor, causing the motor to be stopped on detecting such a blockage and means for adjusting the bottom stopping point corresponding to the desired state of unrolling, characterized in that the means for stopping the blind in the desired unrolled position consist of a screw (6) mounted coaxially and rotationally integral with said output shaft (4, 11) in a cylindrical cage (9) prevented from rotating in the casing by manually actuable blocking means (17) and of a traveling nut (7) mounted on the screw and prevented from rotating in said cage, the motor being stopped in the completely rolled-up position of the blind by the blind coming up against the casing and a blockage of the motor being detected, and the blind being stopped at the bottom stopping point by the traveling nut (7) coming up against a stop integral with the cage (9) and a blockage of the motor being detected, the bottom stopping point being adjusted by unblocking said cage and rotationally driving it.
2. The roll-up device as claimed in claim 1, characterized in that the means (7) for blocking the cage rotating in the casing consist of a transverse meshing screw (17) meshing with helical toothing (16) of the cage, said screw simultaneously constituting the means for adjusting the bottom stopping point.
3. The roll-up device as claimed in claim 1, characterized in that the means for blocking the cage rotating in the casing consist of a screw extending radially relative to the cage, the bottom point being adjusted by unblocking the cage and rotationally driving it, in particular by means of the motor.
4. The roll-up device as claimed in one of claims 1 to 3, characterized in that the cage (9) is pot-shaped and in that said fixed stop consists of the bottom of the cage.

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