Device for control of an electric motor driving a moving object

BACKGROUND OF THE INVENTION

The subject of the present invention is a device for control of an electric motor driving a moving object, for example a roller shutter or a door.

Such a device is known from the DE patent application 27 34 512. In this device, the switch controlling the power supply to the motor is open at rest, and it is closed by a centrifugal mechanism driven by the motor, the starting of the motor being undertaken by a delayed-drop-out start-up relay controlled by a manual push-button switch. The means of starting up the motor and the means of automatic stopping in the event of excess torque are thus combined, but in addition to its relative complexity, such a device requires special-purpose wiring for supplying the start-up relay.

A control device for a motorized roller shutter is also known from the patent EP 0 703 344, operating by detecting a sudden increase in the resisting torque exerted by the roller shutter on the motor. To this end, the chassis of the motor is mounted so that it can rotate and its rotation is limited by two springs acting in opposition and determining the excess torque to be reached in each direction of rotation for the rotation of the chassis to actuate a switch which cuts off the power supply to the motor. The reacting against the moving object may be caused either by its arrival at end-of-travel, or by an obstacle. Starting up the motor is carried out, in the conventional way, by means of a switch.

SUMMARY OF THE INVENTION

A device is provided for control of an electric motor driving a moving object, for example a roller shutter or a door, comprising a switch controlling the power supply to the motor and means for actuating this switch reacting to the moving object being restrained, particularly by an obstacle, so as to cause said switch to be opened and to cut off the power supply to the motor, these actuating means comprising a mechanical actuating device capable of taking up a first state in which the switch is closed and a second state in which the switch is open, and means for putting the mechanical actuating device into its first state, the actuating device being brought into its second state by the reacting against the moving object.

The object of the present invention is also to combine the means for automatic stopping of the motor with the manual control of the starting up of the motor, but via simple mechanical means requiring no auxiliary wiring and using a mechanical manual control, such as a rod control, with a cable or a cord.

The control device according to the invention is characterized by the fact that the mechanical actuating device is a bistable device and in that the means for putting the actuating device into its first state are exclusively manual.

The invention is applicable equally to a motor with one direction of rotation and to a motor with two directions of rotation.

The device requires no external wiring other than that necessary for supplying power to the motor. Installation is thereby simplified.

In its simplest execution, the actuating device is a rotating cam actuating a monostable switch and having, on its periphery, a notch with an angular width corresponding to the rotation of the cam which is necessary for actuating the switch and in which a spigot of the casing of the motor is engaged for driving it when the casing of the motor is driven in rotation, against the action of a spring, by the resisting torque.

According to another embodiment, the bistable mechanical device consists of a cylindrical part which is movable in translation and in rotation within a fixed cylindrical tubular part to which it is linked by the interaction of at least one stud guided by at least one ramp, this moving part being, on the one hand, pushed by a spring in the direction of the switch and, on the other hand, linked to a pulling element which can be actuated manually, making it possible to exert a pulling force opposite to the thrust of the spring, the device being brought into its second stable state either by the rotation of the casing of the motor against the action of a spring, this rotation of the casing being caused by the resisting torque created by said moving object being restrained, or by a further pulling force on the pulling element.

BRIEF DESCRIPTION OF THE DRAWING(S)

The attached drawing, by way of example, represents three embodiments of the invention, as well as two embodiment variants of the first embodiment.

FIG. 1

represents a theoretical diagram illustrating the philosophy of the control device according to the invention.

FIG. 2

, by way of reminder, represents the diagram of an electric motor used in the two embodiments described.

FIG. 3

is a partial view, in perspective, of the first embodiment.

FIGS. 4

a

,

4

b

,

4

c

,

4

d

and

4

e

represent five successive states of the bistable device used in the embodiment represented in FIG.

3

.

FIG. 5

represents a first embodiment variant, and a first improvement respectively, of the first embodiment.

FIG. 6

represents a second variant of the first embodiment.

FIG. 7

is a diagrammatic view in a radial section of a second embodiment applied to the case of a roller shutter.

FIG. 8

is a view in section along VIII—VIII of FIG.

7

.

FIG. 9

is a partial diagrammatic view in a radial section of a third embodiment.

FIG. 10

is a section along X—X of

FIG. 9

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

In

FIG. 1

, C designates a manual control, for example a flexible cord to be pulled or a rigid rod to be pushed/pulled, B is a bistable actuating device, M a motor the casing of which can pivot about the axis of the motor against the action of a retaining spring, and D a detector of the angular offset between the casing of the motor M and a fixed point. The motor M drives a load L, for example a roller shutter. Assuming initially that the power supply switch of the motor is open, that is to say that the actuating device B is in a stable state P, action by the user on the control C has the effect of causing the bistable device B to switch over from its state P into its state P. If, in this state, the angular offset detector D does not detect any angular offset, the motor M is energized. This function can be expressed M=(P & S).

When the detector D detects an angular offset of the casing of the motor, it sends out a stop signal S to the bistable device B which then switches over into its state P. The motor M is no longer supplied with power.

The motor represented in

FIG. 2

is a conventional single-phase motor with two windings and a phase-shifting capacitor, in which each of the windings acts as an auxiliary winding according to whether the power supply voltage is applied between P1 and N or P2 and N.

The first embodiment will be described in connection with

FIGS. 3 and 4

a

to

4

e.

In

FIG. 3

, a cylindrical support

1

is represented, constituting a fixed point, for example one of the supports of the tube for winding a motorized roller shutter. This cylindrical support

1

has two diametrally opposed longitudinal slots

2

. Coaxially with the cylindrical support

1

, and in the extension thereof, is a cylindrical sleeve

3

integral with the casing of the motor (not represented), capable of constituting the extension of this casing. The other end of the casing of the motor is held so as to be able to turn freely about is axis. The sleeve

3

is extended by two longitudinal bars

4

and

5

fixed rigidly to the sleeve

3

and extending respectively in each of the slots

2

of the fixed cylinder

1

. These bars

4

and

5

are held, in angular terms, by means of a pair of springs in a V,

6

and

7

, inserted between each bar and the walls of the corresponding slot

2

. The casing of the motor is thus held in position elastically, in angular terms. The bars

4

and

5

are additionally linked by a crosspiece

8

within the sleeve

3

. This crosspiece

8

, in its mid-part, carries a pair of cams

9

and

10

arranged symmetrically relative to a plane passing through the axis of pivoting of the sleeve

3

. The cam

9

is intended to interact with a first bistable actuating device

11

and the cam

10

to interact with a second bistable actuating device, not represented, arranged, like the cams

9

and

10

, symmetrically relative to the same diametral plane of symmetry. The bistable device

11

actuates a switch

12

which controls the power supply of the motor for one of the directions of rotation. The other bistable device controls a second switch identical to the switch

12

and mounted, like the bistable device, symmetrically relative to the same plane of symmetry.

The bistable device

11

consists of a fixed tubular cylindrical part

13

and of a cylindrical part

14

which is movable in rotation and in translation in the part

13

. The wall of the fixed part

13

is pierced by a slot

15

forming a circuit of ramps and traps for a radial spigot

16

fixed to the movable part

14

passing through the slot

15

with a slight clearance and extending radially outside the part

13

so as to be able to be driven by the cam

9

, as far as the bistable

11

is concerned. The movable part

14

is linked to one end of a rod or cable

17

so as not to be impeded in its rotation. The movable part

14

is furthermore subject to the action of a spring

18

working in compression and tending to push the part

14

toward the switch

12

.

The operation of this embodiment will be described in connection with

FIGS. 4

a

to

4

e.

In the position represented in

FIG. 4

a

, the spigot

16

of the movable part

14

of the bistable is held by the spring

18

in the left-hand end of the circuit

15

close to the switch

12

. The part

14

bears against the pusher of the switch

12

and its contact

12

a

is open: the motor is not supplied with power. If the user pulls on the rod

17

in the direction of the arrow F1, the part

14

is pulled backwards. During this movement, its spigot

16

slides along the ramp

15

a

, driving the part

14

, as indicated by the arrow F2. The spigot

16

finally comes into abutment against the stop

15

b.

When the pulling force on the rod

17

is released, the spigot

16

becomes engaged in the trap

15

c

of the circuit

15

, as represented in

FIG. 4

b

. The bistable device is then in its second stable state. The part

14

is moved away from the switch

12

, its contact is closed and the motor is supplied with power.

If the casing of the motor is then driven in rotation by the reacting against the moving object driven by the motor, for example by the arrival in abutment against the box housing of the end of a roller shutter while it is being wound, the sleeve

3

pivots against the action of one of the springs

6

or

7

, for example the spring

7

, and the cam

9

drives the spigot

16

which escapes from its trap

15

c

so as to come back to its first stable position along the groove

15

, as indicated by the arrow F3,

FIG. 4

c

, under the thrust from the spring

18

. The switch

12

is then actuated, its contact

12

a

opens and the power supply to the motor is cut off.

Stopping can also be controlled manually by pulling on the rod

17

. The bistable device

11

operates in this case as represented in FIGS

4

d

and

4

e

. When there is a pulling force on

17

, the spigot

16

comes into abutment against the ramp

15

d

which moves away from the trap

15

c

. Once released, the spigot

16

moves axially along

15

e

, the ramp

15

f

and brings it back into its position represented in

FIG. 4

a.

If the two bistable actuating devices equipping the control device are independent, nothing prevents the user simultaneously actuating these two bistable devices, that is to say giving two contradictory orders. This can be avoided mechanically or electrically.

FIG. 5

illustrates a mechanical solution. The moving parts

14

and

14

′ of the two bistable devices have an annular groove

19

,

19

′ respectively. Between the two moving parts

14

and

14

′ a slider

20

is mounted, capable of sliding transversely between the two bistable devices and of engaging alternately in the grooves

19

and

19

′. The length of this carriage

20

is such that it is always engaged in one of the grooves

19

or

19

′. In the position represented in

FIG. 5

, the carriage

20

is engaged by one of its ends in the groove

19

of the moving part

14

, while its other end abuts against the cylindrical surface of the moving part

14

′. The part

14

is thus locked, so that a pulling force on its rod

17

has no effect. In contrast, as soon as the part

14

′ comes into abutment against the switch

12

′, the part

14

is freed.

An electrical solution is represented in FIG.

6

. One of the switches, for example the switch

12

, is equipped with an inverter contact making it possible to link terminal a either to terminal b or to terminal c, this terminal c being linked to the switch

12

′ in such a way that the closing of the switch

12

′ is effective only if the switch

12

is actuated and conversely, the actuation of the switch

12

having the effect of bringing the contact

12

b

into the position represented and its release having the effect of bringing it back to the terminal b.

The second mode will now be described in connection with

FIGS. 7 and 8

.

These figures represent one of the ends of a roller shutter installation mounted in a window aperture. The casing

3

of the tubular motor is again visible, housed within a winding tube

21

, shown in part, driven by the motor. The end of the casing

3

which is shown is equipped with a flange

22

by which it is mounted into a rectangular framework

23

complete with a main circular cutout

24

. The flange

22

is equipped with a ring

25

engaged in the circular cutout

24

in which it can turn freely. At its lowest point, the ring

25

is fitted with a first spigot

26

turned toward the center of the ring and with a second radial spigot

27

turned outward, in a rectangular cutout

28

of the framework

23

in which two springs

29

and

29

′ are housed, working against each other in compression and bearing on each of the sides of the spigot

27

. In the center of the ring

25

a switch

30

is fixed, equipped with a bistable latch

31

, that is to say a switch with a central terminal and two contacts for making an electrical connection between the central contact and one or the other of the contacts alternately, that is to say either between N and M1 or N and M2 (

FIG. 2

) so as to make the motor turn in one direction or the other. The visible part of the latch

31

has the profile of an obtuse V. The switch

30

is carried by a support

32

fixed to the framework

23

. Coaxially with the axis X of the motor and of the winding tube, a cam

33

is mounted exhibiting, in its lower part, a notch

34

extending over a well-defined angle, and a projecting part

35

in the form of a dihedron with an angle equal to the angle of the V-shaped profile of the latch

31

of the switch and engaged in this profile. The spigot

26

is engaged in the notch

34

. The space between each of the ends of the notch

34

and the spigot

26

is equal to the angular displacement of the cam

33

which is necessary for actuating the latch

31

, that is to say for closing of the switch

30

in one position or the other. The cam

33

can be driven manually in rotation by a shaft

36

. In order not to risk damaging the switch

30

, the link between the shaft

36

and the cam

33

is an elastic or friction link.

The device is represented at rest, motor stopped. In order to start up the motor, the user turns the shaft

36

in one direction or the other, according to the desired direction of rotation of the motor. The rotation of the cam

33

has the effect, on the one hand, of closing the switch via the dihedron

35

and, on the other hand, of bringing one of the sides of the notch

34

against the spigot

26

. Let us suppose, for example, that the cam

30

was driven in the clockwise direction. It is therefore the right-hand end of the notch

34

,

FIG. 7

, which comes into contact with the spigot

26

. When a resisting torque manages to make the casing

3

turn in the anti-clockwise direction, by compressing the spring

29

′, the spigot

26

drives the cam

33

in rotation in the same direction, which has the effect of bringing the dihedron

35

into the position represented. The power supply to the motor is cut off. After the resisting excess torque disappears, the spring

29

′ brings the casing

3

back into the position represented.

In this mode of execution, the bistable device therefore consists of the switch itself.

The third embodiment represented in

FIGS. 9 and 10

is in fact an embodiment variant of the second embodiment and replicates the majority of the elements thereof, in particular the elements which are not represented. In

FIG. 9

, the ring

25

of the flange of the casing

3

can be seen with its radial spigots

26

and

27

. The rotating cam

33

′ differs from the cam

33

in that it exhibits a projecting central part

37

engaged between two monostable switches

38

and

38

′ the contact of which is open at rest, in contrast to the switches

12

and

12

′ of the first embodiment. The projecting part

37

of the cam has a shape such that, at rest, the switches

38

and

38

′ are not actuated, although a rotational drive of the cam

33

′ by the shaft

36

actuates one or other of the switches via the part

37

. It can therefore be seen that the part

37

can take various shapes, and that it could also be separated into two parts, for example two pips. Moreover, the outer contour of the cam

33

′, like that of the cam

33

, may be of any shape, except for the notch

34

.

The operation of this third embodiment is the same as that of the second embodiment, the only difference being that the bistability is provided here by the cam

33

′. In the actuated position of one of the switches, the stability of the cam is ensured by the friction between the pusher of the switch and the cam. This stability could be increased by forming a slight recess in the part

37

. The stability in the neutral position could be ensured by friction or by an auxiliary means such as an elastically mounted ball. By means of such a ball, it would be possible to provide stability of the cam

33

′, in its three positions. Such means could also be provided on a knob for driving the shaft

36

.

The bistability can also be provided by offsetting the switches

38

and

38

′ downward, in such a way that their pushers are situated under the axis of pivoting of the cam

37

.

Although illustrative embodiments of the invention have been shown and described, a wide range of modification, changes and substitutions is contemplated in the foregoing disclosure. 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.