GB1596961A - Electromagnetic control device - Google Patents

Description

(54) ELECTROMAGNETIC CONTROL DEVICE (71) We, ETABLISSEMENTS CARPANO & PONS, a French Body Corporate, of Place du Cretet-74302 Cluses, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to electromagnetic control devices, comprising a plurality of electromagnets each able to move at least one movable flexible contact support plate.

In known electromagnetic control devices of this type, the electromagnets, which control movement of flexible support plates each bearing the movable contact of at least a pair of electrical contacts of a contact set, are arranged independently of each other and nothing is provided to prevent undesired movement of the movable support plate controlled by a said electromagnet, when another movable support plate is moved by its electromagnet. Incorrect operations are thus possible at the time of the movement of any movable support plate by its electromagnet.

This is the case in the device illustrated diagrammatically in Fig. 1 of the accompanying drawings, which is provided for controlling the rotation of a motor of, for example, a washing machine. This control device comprises two electromagnets 1 and 2.

The electromagnet 1 controls a reversing device constituted by two contact sets 3 and 4, whereof one is closed when the other is open. The contact set 3, which is closed when the electromagnet I is de-energised, controls the rotation of the motor in a first direction (herein called direction A), at slow speed.

The contact set 4 is open when the electromagnet 1 is de-energised. When the electromagnet 1 is energised the contact set 3 opens and the contact set 4 is closed to control the rotation of the motor at slow speed in the opposite direction (herein called direction B).

Contact set 5 is normally open but closes when electromagnet 2 is energised. The closed contact set 5 controls rotation of the motor at high speed in direction A. The device is intended to operate so that contact set 5 is closed to cause transition to high speed rotation from low speed only when the motor is rotating in the direction A at slow speed, known as the "preferred" direction. A pre-established programme can control the rotation of the motor at slow speed alternately in the direction A and in the direction B, during the washing operation, by alternately controlling the closure of the contact set 3 and the contact set 4. The programme then controls the rapid rotation of the motor in direction A, whilst the contact set 3 is closed.

This device has drawbacks, in particular if it is used in an electronic programmer, since stray currents may energise electromagnet 1 and cause the closure of the contact set 4 when the contact set 5 is closed for high speed spin-drying. Such a closure of contact set 4 causes a change in the direction of rotation of the motor whilst it is rotating at the high spin-drying speed. This may result in more less rapid deterioration of certain electrical or mechanical parts of the machine.

In order to control the rotation of the motor at slow speed in the preferred direction A, it is necessary to choose that this be done by the contact set 3 which is closed when the electromagnet 1 is de-energised. If instead one chose to control the low speed rotation in direction B from the closed contact set 3 and the low speed rotation in direction A from contact set 4 which only closed when electromagnet 1 is energised, then an accidental interruption in the winding of electromagnet 1 would result in contact set 3 closing to cause a reversal of the direction of rotation during the spin-drying operation.

According to the invention there is provided an electromagnetic control device comprising a plurality of electromagnets each able to move at least one movable flexible contact support plate, at least one rocking lever of insulating material located between at least two of the flexible plates, a part of the lever constituting an abutment for one of two said flexible plates when another part of the lever is moved by the other flexible plate, said electromagnets being located side-by-side on an insulating casing, and the rocking lever having a pivot point comprising a notch in the lever, a knifeshaped part on the casing, the notch and knife-shaped part being in mutual engagement, a rounded part on the lever, and means for cooperating with said rounded part on the lever to maintain said mutual engagement.

The invention will now be further de scribes by way of example, with reference to the accompanying drawings in which: Fig. 2 is a section on the line 11-il of Fig.

3 of a fragment of an electromagnet control device formed according to the invention; Fig. 3 is a section on line III--III of Fig. 2, and Figs. 4. 5 and 6 diagrammatically show the device in Figs. 2 and 3 during use of the device to control, for example, operations of a washing machine.

In Figs. 2 and 3, the control device comprises three electromagnets 11, 12, 13 mounted on and in an insulating casing 14 which interconnects the electromagnets.

Each electromagnet comprises a winding 15, a magnetic circuit 16, a plunger core 17 terminating at one end in an armature 18 and at the other end in an insulated rod 19 whose end part passes through an orifice 20 in the magnetic circuit 16. Located in the path of the insulated rods 19 of the electromagnets 11, 12 and 13 are movable members constituted by flexible contact support plates 21, 22 and 23 respectively secured at 27 at their end opposite their respective contact 28, 29 or 30.

Located opposite each movable contact 28, 29, 30 is a stationary contact 31, 32 and 33 respectively. These contacts are connected electrically to conductors such as 34 provided on a printed circuit 35 serving as a support for the insulated casing 14 and the arrangement of the control device.

Located respectively between the plates 21 and 22 and between the plates 22 and 23 are two mechanical connecting members, constituted by rocking levers 38 and 39. Each rocking lever is pivoted at its central part by means of a V-shaped notch 40 provided in its upper part in which a knife-shaped part 41 of the casing 14 is housed, the notch 40 and part 41 being thus mutually engaged. A lower part of the rocking lever is rounded in the shape of an arc of a circle, and is supported on a rib 42 to maintain the mutual engagement of the notch and corresponding knifeshaped part. The rib 42 is provided on a small bar 43 located transversely with respect to the casing 14. The bar 43 extends substantially parallel to the row of the electromagnets 11, 12 and 13, and the bar 43 is housed in notches 44 provided in the casing 14. The two ends of each rocking lever 38 or 39 comprise rounded parts 45 and 46 respectively, intended to bear against the corresponding contact support plate with which they co-operate. Each rounded part 45, 46 is located on the trajectory followed by one of the plates 21, 22, 23 as the plate moves from a contacts open to a contacts closed position.

The plate 21 is shown in Fig. 2 in its normal position position, the contact set 28, 31 being open, the plate 21 maintaining the armature 18 of the de-energised electromagnet 11 raised.

If an electromagnet, for example the electromagnet 12 in Figs. 2 and 3, is excited, its armature 18 and its plunger core 17 move downwards in the direction of arrow 48 thus entraining the plate 22 in the same direction, so that the plate assumes its operative position in which the contact set 29, 32 is closed.

During its movement in the direction of arrow 48, the plate 22 entrains the rounded part 46 of the rocking lever 38 in the same direction, which causes the movement in the opposite direction, namely in the direction of arrow 49, of the rounded part 45 of the same rocking lever 38. The plate 22 also entrains the rocking lever 39 whose rounded part 46 moves in the direction of arrow 49. Thus if one of the other electromagnets, for example the electromagnet 11, is excited, the rounded part 45 of the rocking lever 38 constitutes an abutment which prevents the movement in the direction of arrow 48 of the plate 21 which itself prevents the movement of the plunger 17 and the corresponding insulating rod 19 in the same direction. In fact, the maintaining force of the electromagnet 12, which in this example is approximately 250 grammes, is much greater than the force of attraction of the electromagnet 11 necessary for initiating movement the plunger core 17 of the electromagnet 11 in the direction of arrow 48. In fact, in this example, this force of attraction has a value of the order of 25 grammes. The same would be true if the electromagnet 13 were excited. The rounded part 46 of the rocking lever 39 would prevent the movement in the direction of arrow 48 of the plate 23 and the corresponding plunger core 17.

Figs. 4, 5 and 6 show diagrammatically an application of the control device illustrated in Figs. 2 and 3, to the control of operations of a washing machine. When they are closed, the contact sets 28, 31 and 29, 32 respectively control the directions of rotation A and B of a motor 60 at slow speed, provided for carrying out a washing operation. The contact set 30, 33 controls the rotation of the motor 60 in the so-called "preferred" direction A at high speed, provided for carrying out a spin-drying operation. The closure or opening of these various contacts is controlled for example, by an electronic programming device (not shown) which excites one or other of the electromagnets 11, 12 or 13, at the desired instant.

When the electromagnet 12 is excited, the contact set 29, 32 is closed and the motor 60 rotates at slow speed in the direction B. The various members occupy the position illustrated in Fig. 4. The rocking lever 38 prevents the contact set 28, 31 from closing, even if the electromagnet 11 is excited inopportunely, which prevents the two directions of rotation of the motor being called for simultaneously. Similarly, the rocking lever 39 prevents the switch 30, 33 from closing, even if the electromagnet 13 is excited inopportunely, which prevents a demand being made on the motor 60 to rotate in direction A at high speed at the time when it is rotating in direction B at slow speed.

When the electromagnet 12 is no longer excited, the programming device demands the excitation of the electromagnet 11, which closes the contact set 28, 31 and the motor 60 rotates at slow speed in the preferred direction A. The various members now occupy the position shown in Fig. 5. The rocking lever 38 prevents the closure of the contact 29, 32 controlling the other direction of rotation B of the motor 60. The rocking lever 39 does not prevent possible closure of the contact set 30, 33 subsequent to excitation of the electromagnet 13.

The motor 60 is thus set in rotation at the slow speed, alternately in the directions A and B. When the washing operation is completed and whilst the electromagnet 11 is excited and the motor 60 is rotating in the direction A, the programming device causes the excitation of the electromagnet 13 and the closure of the contact set 30, 33 and simultaneously the opening of the contact set 28, 31. The motor 60 thus continues to rotate in the direction A, but at high, spin-drying speed. The various members thus occupy the position shown in Fig. 6. The rocking lever 39 prevents the closure of the contact set 29, 32 controlling the rotation of the motor 60 in the other direction of rotation B, which thus prevents an attempt to change the direction of rotation of this motor 60 whilst the latter rotates at high speed. This could be the case if, for example, stray currents accidentally caused an excitation of the electromagnet 12.

On the other hand, an interruption occurring accidentally, during the spin-drying operation, in the winding of the electromagnet 11 would cause solely the stoppage of the motor 60 and not its rotation in the reverse direction B. The spin-drying operation would only be interrupted. Thus, in all cases, the electrical or mechanical parts of the washing machine are protected from damage.

The electromagnetic control device described above with reference to the drawings may be used for controlling machine parts or mechanisms electrically or mechanically, with safety. It may or may not be incorporated in an electronic programmer. It may be used, for example, for controlling operation of a washing machine or dish-washing machine.

WHAT WE CLAIM IS: 1. An electromagnetic control device comprising a plurality of electromagnets each able to move at least one movable flexible contact support plate, at least one rocking lever of insulating material located between at least two of the flexible plates, a part of the lever constituting an abutment for one of two said flexible plates when another part of the lever is moved by the other flexible plate, said electromagnets being located side-by-side on an insulating casing, and the rocking lever having a pivot point comprising a notch in the lever, a knifeshaped part on the casing, the notch and knife-shaped part being in mutual engagement, a rounded part on the lever, and means for cooperating with said rounded part on the lever to maintain said mutual engagement.

2. An electromagnetic control device substantially as hereinbefore described with reference to Figs. 2 to 6 in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. contact set 29, 32 is closed and the motor 60 rotates at slow speed in the direction B. The various members occupy the position illustrated in Fig. 4. The rocking lever 38 prevents the contact set 28, 31 from closing, even if the electromagnet 11 is excited inopportunely, which prevents the two directions of rotation of the motor being called for simultaneously. Similarly, the rocking lever 39 prevents the switch 30, 33 from closing, even if the electromagnet 13 is excited inopportunely, which prevents a demand being made on the motor 60 to rotate in direction A at high speed at the time when it is rotating in direction B at slow speed. When the electromagnet 12 is no longer excited, the programming device demands the excitation of the electromagnet 11, which closes the contact set 28, 31 and the motor 60 rotates at slow speed in the preferred direction A. The various members now occupy the position shown in Fig. 5. The rocking lever 38 prevents the closure of the contact 29, 32 controlling the other direction of rotation B of the motor 60. The rocking lever 39 does not prevent possible closure of the contact set 30, 33 subsequent to excitation of the electromagnet 13. The motor 60 is thus set in rotation at the slow speed, alternately in the directions A and B. When the washing operation is completed and whilst the electromagnet 11 is excited and the motor 60 is rotating in the direction A, the programming device causes the excitation of the electromagnet 13 and the closure of the contact set 30, 33 and simultaneously the opening of the contact set 28, 31. The motor 60 thus continues to rotate in the direction A, but at high, spin-drying speed. The various members thus occupy the position shown in Fig. 6. The rocking lever 39 prevents the closure of the contact set 29, 32 controlling the rotation of the motor 60 in the other direction of rotation B, which thus prevents an attempt to change the direction of rotation of this motor 60 whilst the latter rotates at high speed. This could be the case if, for example, stray currents accidentally caused an excitation of the electromagnet 12. On the other hand, an interruption occurring accidentally, during the spin-drying operation, in the winding of the electromagnet 11 would cause solely the stoppage of the motor 60 and not its rotation in the reverse direction B. The spin-drying operation would only be interrupted. Thus, in all cases, the electrical or mechanical parts of the washing machine are protected from damage. The electromagnetic control device described above with reference to the drawings may be used for controlling machine parts or mechanisms electrically or mechanically, with safety. It may or may not be incorporated in an electronic programmer. It may be used, for example, for controlling operation of a washing machine or dish-washing machine. WHAT WE CLAIM IS:

1. An electromagnetic control device comprising a plurality of electromagnets each able to move at least one movable flexible contact support plate, at least one rocking lever of insulating material located between at least two of the flexible plates, a part of the lever constituting an abutment for one of two said flexible plates when another part of the lever is moved by the other flexible plate, said electromagnets being located side-by-side on an insulating casing, and the rocking lever having a pivot point comprising a notch in the lever, a knifeshaped part on the casing, the notch and knife-shaped part being in mutual engagement, a rounded part on the lever, and means for cooperating with said rounded part on the lever to maintain said mutual engagement.

2. An electromagnetic control device substantially as hereinbefore described with reference to Figs. 2 to 6 in the accompanying drawings.