Powered rolling shutter equipped with automatic stopping means

BACKGROUND OF THE INVENTION

The invention relates to a motorized roller shutter or the like comprising an electric drive motor the stator of which is connected to a fixed support via elastic means which oppose the rotation of the stator under the effect of the resistive torque exerted by the roller shutter moving between a rolled up up position and an unrolled down position, stop means stopping the roller shutter in these up and down positions and means of controlling the stopping of the motor in these up and down positions comprising a switch the opening of which is actuated by the rotation of the stator when the resistive torque exceeds the retaining force exerted by the elastic means.

PRIOR ART

Roller shutters thus equipped are described in patents FR 2 740 824, the content of which is incorporated by reference, U.S. Pat. No. 6,392,374, the content of which is incorporated by reference, and EP 0 703 344, the content of which is incorporated by reference.

The roller shutter described in patent FR 2 740 824 uses a single spring. The switch is open when the roller shutter is in the unrolled position and the motor is powered via an auxiliary switch controlled by a revolutions counter associated with the motor. Such a roller shutter has to be mounted in a determined position in a window aperture.

The roller shutters described in patents U.S. Pat. No. 6,392,374 and EP 0 703 344 are equipped with two antagonist springs between which the stator of the motor is held. One of these springs is compressed when the roller shutter, completely rolled up, arrives at a top stop, while the other spring is compressed when the roller shutter, completely unrolled, has reached the bottom stop, generally against the bottom of the aperture. Now, as described in patent FR 2 740 824, the top stop spring has to be able to oppose the torque generated by the weight of the roller shutter. Now, when the shutter is almost completely unrolled, this weight may be very great. By contrast, the spring which controls the stopping of the motor when the roller shutter reaches the bottom stop has to give relatively readily in order to avoid needless compression of the shutter reaching the bottom stop, which compression could damage the shutter. It is therefore necessary to have two springs, one of them very strong, for the top stop, and the other far weaker, for the bottom stop. Now, by equipping the stopping device with two different springs, the direction of rotation of the motor corresponding respectively to the rolling-up and to the unrolling of the roller shutter, is determined, and this means that the motor has always to be arranged on the same side of the aperture, given that if the motor is arranged on the opposite side of the aperture its direction of rotation will have to be reversed, for the same position of the roller shutter, of course, which is generally the case. This represents a constraint that cannot always be satisfied and it is therefore necessary to have two motors with their stopping control device, one for mounting on the left and the other for mounting on the right of the aperture.

SUMMARY OF THE INVENTION

The object of the invention is to produce a roller shutter the motor and the stopping device of which can be mounted with equal ease on either side of the aperture. The stopping device has also to be compact so that it can be arranged inside a motor, particularly a tubular motor, without increasing the size thereof.

The roller shutter according to the invention is characterized in that the elastic means consist of two springs working in compression between two moving compression elements driven in turn by the stator respectively in each of the directions of rotation, the distance to be covered by the driven moving element, from the rest position, before one of the springs is compressed, exceeding the distance to be covered by the driven moving element before the other spring is compressed, and in that the stopping device comprises an actuating member kinematically linked to the stator and, on the one hand, driving the compression elements and, on the other hand, actuating the switch after a determined travel which differs for each direction of rotation of the stator and means of reversing the lengths of the travels.

When the stator rotates, just one spring is compressed first of all, this compression corresponding to the shortest travel of the actuating member, that is to say to the stopping of the motor when the roller shutter reaches the bottom stop. When the moving drive element moves in the opposite direction corresponding to its long travel, just one spring is compressed first of all, then both springs are compressed, offering significantly more resistance, this situation corresponding to the roller shutter arriving at the top stop. Actuation of the means of reversing the travel lengths makes it possible to obtain the same result when the motor is rotating in the opposite direction.

The distance to be covered by the driven moving element before one of the springs is compressed may be zero.

The springs are advantageously helical, with different diameters and nested coaxially one inside the other. Such a construction is particularly compact. To simplify the construction, the compression elements advantageously have a single distance between them and the springs are of different lengths.

The spring compressed second is advantageously pre-compressed at rest. Both springs may be pre-compressed. Pre-compressing the springs makes it possible to operate on a gentle slope with short travel, which allows better control over the forces developed by the springs and therefore makes it possible to enjoy great precision in the triggering forces, particularly in that of the spring which is compressed by itself which has not to be too high in order not to damage the roller shutter. Pre-compression also makes it possible to reduce the size of the stopping device.

The actuating member may be part of the stator.

According to one embodiment, the actuating member consists of a traveler guided in the support and equipped, on one side, with two arms for driving the compression elements in the compression direction and, on the other side, with two arms for actuating the switch which is mounted between these arms and the means of reversing the length of the travels consist of a rocker mounted between the actuating arms of the switch and equipped with two arms which act alternately as arm for actuating the switch depending on the position of the rocker, the other arm being retracted relative to the switch, the active arm being situated between one of the actuating arms of the traveler and the switch.

According to an improvement of this embodiment, the arms of the rocker are flexible in a direction parallel to its axis of pivoting and the stopping device comprises a fixed stop situated in the path of the arms of the rocker, facing the open position of the switch, this stop having the effect of moving the active actuating arm of the rocker away from its normal active path so as to make it inoperative. This improvement prevents the motor from being powered in the rolling-up direction if an attempt is made at raising the roller shutter by hand, for example in the event of an attempted break-in.

According to another embodiment, the switch is mounted between the arms of the traveler and can move in the same direction as the traveler, so as to be able to alter the distance separating it from each of the actuating arms of the traveler, that is to say the length of the travel needed to actuate it using the traveler in each of the directions of rotation of the stator.

According to one embodiment, the springs are mounted in a cage one of the ends of which has a lateral arm driven directly by the traveler, the compression element compressing the other ends of the springs consisting of a part in the form of a piston entering the cage and the strongest spring which is pre-compressed between the two ends of the cage.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawing depicts, by way of example, some embodiments of the invention. To simplify, the cylindrical surfaces are depicted as straight, that is to say in development.

FIG. 1

depicts, as a reminder, a tubular motor driving a roller shutter winding tube.

FIG. 2

is a schematic side view of a first embodiment of the stopping device.

FIG. 3

is a view in section on III—III of FIG.

2

.

FIG. 4

is a view in section on IV—IV of FIG.

2

.

FIG. 5

schematically depicts the conditions to be met by the springs and the compression elements.

FIG. 6

schematically depicts an alternative form of embodiment of

FIG. 2

in which the strongest spring is highly compressed.

FIG. 7

is a part view in section on VII—VII.

FIG. 8

illustrates an improvement to the embodiment depicted in FIG.

2

.

FIG. 9

is a side view on IX—IX of FIG.

8

.

FIG. 10

is a schematic view of a second embodiment.

FIG. 11

is a perspective view of one embodiment of the spring cage.

FIG. 12

is another perspective view of this cage.

FIG. 13

is a view in axial section of the cage depicted in

FIGS. 11 and 12

.

FIG. 14

is a schematic view similar to

FIG. 2

but in which a cage according to

FIGS. 11

to

13

is mounted.

FIG. 15

illustrates an alternative form of the embodiment depicted in

FIG. 2

, in which the inverter is replaced by two bistable switches.

FIG. 16

depicts the electrical diagram for controlling the motor using an inverter.

FIG. 17

depicts the electrical diagram for controlling the motor using two bistable switches.

FIG. 18

depicts the electrical diagram of a first alternative form with two monostable switches, which is applied to a conventional diagram comprising an additional control contact switch.

FIG. 19

depicts the electrical diagram of a second alternative form with two monostable switches controlling a control contact switch contained in a radio receiver.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

FIG. 1

schematically depicts a well known way of driving a roller shutter, described for example in patent U.S. Pat. No. 5,105,871, the content of which is incorporated by reference. It is possible to discern a winding tube

1

about which a roller shutter is rolled up. This winding tube

1

, depicted in part, is borne, on the side depicted, by an annulus

2

mounted to rotate on the cylindrical tubular casing

3

of an electric geared motor unit. The other end of the winding tube

1

is mounted so as to rotate on a support which has not been depicted. The casing

3

is mounted on a fixed support

4

, for example, in the aperture of a window. Thus, mounted in the tubular casing

3

are an electric motor associated with reduction gearing the output of which drives an annulus

5

itself driving the rotation of the winding tube

1

.

As is the case of the constructions described in patents FR 2 740 824 and U.S. Pat. No. 6,392,374, the casing

3

of the motor, and therefore the motor stator fixed to this casing, is connected elastically to the fixed support

4

in such a way as to be able to turn slightly about its axis denoted in

FIG. 1

by the reference

6

.

This elastic connection is depicted in

FIGS. 2

to

4

. Mounted coaxially in a housing

7

of the fixed support

4

are two springs R

1

and R

2

, the spring R

1

, longer than the spring R

2

and of smaller diameter, being mounted inside the spring R

2

which itself is substantially stronger than the spring R

1

. These springs R

1

and R

2

are mounted between two compression pieces

8

and

9

equipped, on the one hand, with a guiding arm

8

a

and

9

a

respectively which are mounted to slide freely in guide slots

10

and

11

of the fixed support

4

. The compression pieces

8

and

9

are also equipped with a lateral arm

8

b

,

9

b

so that they can be driven by the arms

13

and

14

respectively of a traveler

12

which is secured to the casing

3

so as to rotate as one therewith by an arm

12

c

(

FIG. 3

) and guided in the fixed support

4

in guides

15

and

16

so as to move parallel to the springs R

1

, R

2

. This traveler

12

has two parallel arms

12

a

to

12

b

opposite the arms

13

and

14

. Mounted between these arms

12

a

and

12

b

is the arm

17

of a reversing switch

18

. The arm

17

can occupy three positions, a central position O in which the switch is open, a position M in which the motor is powered in the raising direction, that is to say in the direction for rolling up the roller shutter, and a position D in which the motor is powered in the down position, that is to say in the direction for unrolling the roller shutter. The traveler

12

bears a rocker

19

articulated about an axis

20

transversely to the traveler. This rocker

19

is equipped with two arms

19

a

and

19

b

which can be positioned, in turn, between the arms

12

a

and

12

b

of the traveler so that, in this position, the arm can actuate the switch when the traveler moves.

The device is depicted in its rest position. It is assumed first of all that the roller shutter is completely rolled up. Unrolling is triggered by the switch being placed in the position D which has the effect of powering the winding S

2

of the motor (FIG.

16

). When the roller shutter comes against the bottom stop it exerts on the motor a resistive torque which has a tendency to drive the casing

3

and therefore the traveler

12

, connected to the casing

3

, in the direction of the arrow F

1

. The arm

14

of the traveler exerts thrust on the arm

9

b

of the compression piece

9

. When the resistive torque is high enough to compress the spring R

1

, the traveler moves in the direction F

1

and, after a certain travel, the arm

19

b

of the rocker meets the arm

17

of the switch. After a travel c

1

this arm

17

is brought into the position O. The power supply to the motor is cut off.

The rolling-up of the roller shutter is brought about by placing the switch in the position M which has the effect of powering the winding S

1

of the motor (FIG.

16

). When the roller shutter reaches the top stop, it exerts on the motor a resistive torque which has the tendency to drive the traveler

12

in the direction of the arrow F

2

. This resistive torque is soon sufficient for the traveler

12

to drive the compression piece

8

via its arm

13

, compressing the spring R

1

. The compression piece continuing to move then compresses the two springs R

1

and R

2

, the switch

18

being brought into the position O only when the arm

12

a

of the traveler has covered the travel c

2

which is substantially greater than the travel c

1

. In this case, the resistive torque needed to actuate the switch is therefore substantially higher than the resistive torque needed to stop the motor against the bottom stop.

If the motor

3

with its support

4

are mounted on the other side of the aperture, so that the direction of rotation of the motor for rolling up and unrolling is reversed, then the rocker

19

is rocked into the position shown in chain line and it is then the arm

19

in the position

19

a′

which actuates the switch. The travels c

1

and c

2

are therefore reversed and the device for stopping the motor is thus adapted to the change in direction of rotation of the motor.

In

FIG. 2

, the spring R

1

can be slightly pre-compressed. By contrast, the spring R

2

is not pre-compressed at rest.

It is, however, more advantageous to work with two pre-compressed springs, as this makes it possible to use springs with a gentle slope and to operate linearly over short travels, which makes it possible to have better control over the forces developed by R

1

and R

2

and therefore makes it possible to enjoy great precision in the triggering forces, particularly in those of the spring R

1

which has not to be too high in order not to damage the shutter.

The different lengths and the different stiffnesses of the springs are not necessary conditions for obtaining the desired result. The springs could have the same stiffness. It would be sufficient for a travel c

1

of the traveler for just one spring to be compressed and, for a longer travel c

2

, for both springs to be compressed.

FIG. 5

illustrates these conditions for compression elements

8

,

9

compressing two springs, here depicted in parallel. The distance between the compression elements for each of these springs is not necessarily the same. In general, for the spring R

1

to be compressed by itself first of all, it is necessary and sufficient for 12 to be greater than 11, that is to say for the distance 12 to be covered by the driven compression element before it compresses R

2

to be greater than the distance 11 to be covered by the compression element before it compresses R

1

.

In general, there will be 11=zero, that is to say that there is no dead travel. The spring R

2

may be pre-compressed or not.

FIG. 6

illustrates schematically an alternative form of embodiment of the embodiment depicted in

FIG. 2

, in which alternative form the two springs R

1

and R

2

are pre-compressed. The spring R

1

is pre-compressed between the compression pieces

8

and

9

. The spring R

2

is pre-compressed in a cage

20

, more specifically between two pairs of forks

21

and

22

of this moving cage which is guided in a guide

23

of the fixed support

4

. These forks

21

and

22

allow the compression pieces

8

and

9

to pass. In the direction F

1

, the compression piece

9

can thus pass through the fork

22

to compress the spring R

2

when the fork

21

comes into abutment and, conversely, the compression piece

8

can pass through the fork

21

to compress the spring R

2

.

FIGS. 8 and 9

schematically illustrate an improvement to the first embodiment or to its alternative, avoiding reapplication of power to the motor in the raising direction if, once the shutter has stopped in the down position, it is lifted up by hand by its last lath, for example during an attempted break-in. In this case, if

FIG. 2

is considered, the thrust on the roller shutter exerts on the motor a torque in the direction of the arrow F

1

, that is to say a torque the direction of which is the same as the resistive torque which caused the motor to stop. The traveler

12

will therefore rock the switch into the position M which causes the rolling-up of the roller shutter. To prevent this, the traveler

12

is equipped with a rocker

19

the arms of which are flexible at least in a direction parallel to the axis of articulation of the rocker and fixed to the support

4

is a stop

24

which, on each side, has a ramp

24

a,

24

b

and is placed, between the arms of the traveler

12

, in the path of the active arm of the rocker

19

, for example the arm

19

b.

The top of the stop

24

also faces the position O of the switch

18

. When the roller shutter is unrolled in the down position and stopped, the switch

18

is in the position O. When the roller shutter is lifted up, the arm

19

b

of the rocker meets the ramp

24

b

which moves the arm away from its normal path as depicted by the arrow F

3

, so that it does not meet the arm

17

of the switch and so that the motor is not powered.

Reversing the lengths of travel c

1

and c

2

can also be obtained by moving the switch. This alternative is depicted in FIG.

10

. The switch

18

is mounted in a moving support

25

which can be moved in a housing

26

of the fixed support

4

. The moving support

25

is equipped with guide arms sliding in a guide of the fixed support

4

. The moving support

25

is used in abutment against one or other of the ends of the housing

26

.

One practical embodiment of the part of the stopping device concerning the springs R

1

and R

2

is depicted in

FIGS. 11

to

13

.

The springs R

1

and R

2

are mounted in a cage

27

consisting of a transverse wall

28

forming the end of the cage and of two arms

29

and

30

extending from the wall

28

parallel to the axis of the springs and connected, near their ends, by a bow

31

. The ends of the arms

29

and

30

end in two walls

32

and

33

which are mutually parallel and parallel to the axis of the springs. The spring R

2

is pre-compressed between the end

28

of the cage and the edge of the walls

32

and

33

. Also extending from the end

28

is a tubular part

34

surrounded by the spring R

2

. This tubular part serves to guide the spring R

1

engaged freely in this part

34

so as to press against the end

28

. At the end

28

, the arm

30

of the cage is bent twice at right angles to form a radial tab

37

by which the traveler

12

can drive the cage.

Also engaged in the spring R

2

is a part

35

in the form of a hollow piston, at the end of which the other end of the spring R

1

rests. This part

35

has a head

36

of a diameter that exceeds the body of the piston

35

but which is cut with two parallel flats so that the head

36

can pass between the walls

32

and

33

of the cage. The head

36

can therefore compress the spring R

2

.

The use of the cage depicted in

FIGS. 11

to

13

in a stopping device according to

FIG. 2

is depicted schematically in FIG.

14

. The arm

13

of the traveler

12

rests directly on the head

36

of the piston

35

which piston, at rest, also rests against the fixed support

4

. The radial arm

34

can be driven by the arm

14

of the traveler. The arm

29

of the cage

27

is used for guiding the cage, that is to say for preventing it from rotating about its axis. To this end, the arm

29

is engaged in a guide slot. At rest, the spring R

1

is also pre-compressed. The piston

35

thus has to be kept pushed slightly into the cage

27

in order to mount this cage in the fixed support

4

. In this case, the compression pieces

8

and

9

consist respectively of the head

36

of the piston and of the end

28

of the cage

27

.

Apart from these few embodiment differences, the way in which the device works is the same as in the case of the device depicted in FIG.

6

.

In the devices depicted in

FIGS. 2

,

6

and

8

to

10

, it is possible to replace the reverser

18

with a pair of switches. By way of example,

FIG. 15

depicts a modification to

FIG. 2

in which up and down stoppage is provided by two bistable switches

18

′ and

18

″. The switch

18

′ controls stopping in the down direction. It is depicted in the closed position. The switch

18

″ controls stopping in the up direction. It is depicted in the open position.

The device is depicted in its position of rest as in FIG.

2

. It is assumed that the shutter is completely rolled up. Unrolling is triggered by action on the switch

18

′ placed in the down position D (FIG.

17

). The device works in the same way as the device according to FIG.

2

. To raise the shutter, the switch

18

″ is placed in the up position M.

Instead of bistable switches it is possible to use monostable switches by adapting the control circuit.

In the diagram depicted in

FIG. 18

, use is made of two monostable switches

118

′ and

118

″, which are closed in the rest position, in conjunction with a control switch

119

. The switches

118

′ and

118

″ correspond to the circuit breakers in a conventional diagram.

In the diagram depicted in

FIG. 19

, the bistable switches

218

′ and

218

″ are open in the rest position. They control a control contact switch of the installation which is contained in a radio receiver

219

. The contact switch can also therefore be controlled by a transmitter.

Although illustrative embodiments of the invention have been shown and described, a wide range of modification, change and substitution is contemplated in the foregoing disclosure and in some instances, some features of the present invention may be employed without a corresponding use of the other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.