DE8701561U1 - Control circuit for roller blind drive - Google Patents

Description

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Control circuit for RoI&Igr;&ogr; drive

This innovation relates to a control circuit for a roller blind drive and is also applicable to other applications, such as driving curtains on curtain rails for opening and closing or all applications where a limit switch on both sides and a braked intermediate position are necessary.

The previously known control circuits for roller blind drives had the disadvantage that these control circuits were relatively complicated and expensive. All previously known control circuits were based on the problem that the direction of rotation of a motor had to be reversed, and so-called pole strips are common here. The aim of this innovation is to further develop a control circuit of the type mentioned at the beginning in such a way that a significantly lower circuit effort is required and that the control circuit in question still works reliably and safely.

To solve the problem, the innovation is characterized by the technical teaching according to claim 1. There are therefore two relays whose normally closed contacts, connected in series, short-circuit the motor.

This ensures that when the power is off, the motor is always short-circuited and thus electrically locked.

A limit switch is arranged in each line branch to the DC motor, with one limit switch for the upper end position and the other limit switch for the lower end position

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corresponds.

A relay excitation coil is arranged in each of the two lines to the electric motor, whereby the relays have both a resting contact and a working contact. The resting contacts of the two relays are connected in series and short-circuit the motor when the relays are de-energized.

It is important that on this bridge, which is connected to the two contacts assigned to the idle state, one pole of the

^ Power supply is switched on, for example the positive pole. This ensures that the motor has positive potential at both winding ends. The two excitation coils are led to a changeover contact, with each excitation coil being assigned to a changeover contact.

The middle contact of the switch is connected to the other potential.

This design has the significant advantage that, depending on the position of the switch, negative potential is applied to one or the other excitation coil, for example, and that the ( \ new circuit diagram provides a current flow through the Motor takes place due to the positive potential of the relay that is not carried by the current flow.

The motor then starts in the described switching position and the current flow is only interrupted by a limit switch.

The limit switch is designed so that it can interrupt the full motor power.

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This means that the relay contacts switch off without power and are subject to much less wear. If the drive is to be stopped in any intermediate position, the switch is operated, the circuit is interrupted and the associated relay contact switches off without power.

Several embodiments of the present innovation are now described in more detail with reference to the drawings.

The drawing and its description show further features and advantages of the innovation.

Figure 1 shows a first embodiment of the invention with a motor 1 which is designed as a direct current motor and which can be braked in a short circuit with its short-circuit current.

One motor winding is connected via line 2 and a limit switch 4 to one end of the excitation coil 6 of a first relay 22. The other end of the excitation coil is connected via line 8 to one pole of a changeover switch 12.

The other end of the winding of the motor 1 is in turn connected via the line 3 and the limit switch 5 to one pole of the excitation coil 7, the other pole of which is connected via the line 9 to the other contact of the changeover switch 12.

The excitation coils 6,7 are each connected to an armature in a manner known per se, which actuates a changeover switch 24,25.

In the rest position shown, the excitation coils 6,7 are not traversed by current and the changeover switches 24,25 are therefore

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assigned rest contacts 16,17. The rest contacts 16*17 are connected to one another via a bridge 26 _, to which one pole of the power supply - preferably the positive pole - is connected via connection 15.

The changeover switches 24, 25 are in turn connected via lines 18, 19 to the lines 2, 3 in the manner shown, so that in the rest position shown in detail, the lines 18, 19 in connection with the changeover switches 24, 25, the contacts 16, 17 and the bridge 26 form a short circuit across the motor 1, which is thereby electromagnetically locked.

® This ensures that the roller blind or the motor 1

the drive to be driven does not move independently.

The center contact of the switch 12 is connected via the connection 14 to the other pole - preferably the negative pole - of the power supply.

At the same time, the working contacts 20,21 of the relays 22,23 are connected to one connection of the power supply via the lines 10,11.

If the motor is to be driven in one direction, then the changeover switch 12 is moved to the left, for example in the direction of arrow 27, so that one pole of the power supply at connection 14 makes contact with line 9. This causes current to flow through the excitation coil 7 of the relay 23, because the current passes through the limit switch 5, line 3, line 19, the changeover switch 24, the bridge 26 and the connection 15.

With the current flowing through the excitation coil 7, the switch

25 from the rest contact 16 to the work contact 20 and the current now flows via the motor 1, the line 18, the changeover switch 23, the contact 20 and the line 11 to the negative pole of the power supply.

The motor runs until the current flow is interrupted by one of the limit switches 4,5.

When the current flow is interrupted by one of the limit switches 4,5, the current flow through the excitation coil 7 is interrupted, the relay 23 drops out and the changeover switch 25 returns to its position v ' according to Figure 1, i.e. it connects the line 18 to the contact 16 and the bridge 26, whereby the connection to the positive pole of the power supply is established via the connection 15.

The circuit works in an analogous manner if the changeover switch 12 is moved to the right in the opposite direction to the arrow 27 shown, so that the connection 14 is connected to the line 8 and the relay 22 is thereby controlled.

For example, one limit switch 4.5 is assigned to the upper end position of the drive, while the other limit switch 5.4 is assigned to the lower end position of the drive.

Figure 2 shows a modified embodiment, which differs from the previous embodiment in that the lines 11, 12, which are assigned to the working contacts 20, 21 of the relays 22, 23, are not connected to the negative pole of the power supply as in the embodiment according to Figure 1, but the lines 11, 12 are directly connected to the lines 8, 9 in the present embodiment. This results in a simpler structure, whereby the motor current runs through the changeover switch 12, whereas in the

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In the embodiment according to Figure 1, the changeover switch 12 is not traversed by the motor current, but only by the control current for controlling the relays 22, 23.

Overall, the two embodiments described result in a reliable drive for a direct current motor, which is reversible in the direction of rotation, using only a few components. This avoids complicated semiconductor circuits, although the scope of the present innovation also includes the possibility of replacing the fx electromechanical relays described here with corresponding electronic Equivalents can be replaced. The rest and work contacts shown can of course be replaced by corresponding electronic equivalents, whereby it is important to note that the contacts shown are not power contacts, but merely control contacts, which means that the electronic equivalents must be correspondingly small; ie expensive triacs can be avoided and simple TTL flip-flop ¹ S can be used instead.

The core of the present innovation is that in the rest state the motor is short-circuited via corresponding rest contacts of two relays arranged symmetrically in a circuit C ' and the motor is thus braked in the short circuit both when the limit switches and when the changeover switch are operated from its operating position to a middle rest position.

Since both the control current and the motor current are routed together via a single-pole changeover switch, a power-free shutdown is achieved.

Another advantage is that the engine only needs two

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Supply lines must be routed, because the lines 18,19 that cause the motor to short-circuit in the rest position can be installed directly above the limit switches 4,5.

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Claims (4)

.", ." pPATJEWTANWÄLTB ". '"&iacgr; DR.-ING. GVRIEBLING ÖR.-lNG. R RIEBLING Dipl.-lng., Ing. (grad.) Dipl.-lng. EUROPEAN PATENT ATTORNEYS Our symbol /our ret: H 2253-31-ku Please repeat in the answer your reference your message from D-8990 Lindau (Bodensee) Rennerle 10 ■ PO Box 3160 &lgr; February 2, 1987 Reference: Applicant: Senator h.c. Dr.Ing. h.c. Walter Holzer, Drosteweg 19, 7758 Meersburg S chut za &pgr; sayings || 1. Control circuit for a drive for roller blinds, curtains, doors and the like, consisting of a direct current motor, the current flow of which is reversible by means of a current inverter, and in each of whose two current paths a limit switch is arranged, ' characterized in that the current commutator consists of two relays (22, 23) arranged symmetrically to one another in the control circuit, each of which has a changeover switch (24, 25) with at least one normally closed contact (16, 17) and one normally open contact (20, 21), that the excitation coils (6, 7) of the relays (22, 23) are connected to the terminals (2, 3) of the motor (1) via the limit switches (4, 5), that a short-circuit circuit for the motor (1) is formed via a bridge (26) connecting the normally closed contacts (16, 17) and the connection (15) of one pole of the power supply is connected to the bridge, and that the changeover switch (27) used to reverse the direction of rotation of the motor (1) is connected to Telephone: Telex; Facsimile/Fax; Bank accounts; Posicheck account Lindau (Ö 83 821 S 43 U (sponsored) +49-8382-5027 Bayor, Vefelnsbänk Lindau (B) No. (20 857« (bank code 735 200 U) Munich 295 25-809 25 telegfafnm addresses! Gn)IJpIIAlII ₁ . &EEgr;^&udigr;&phgr;&Bgr;&bgr;&rgr;&Igr;&iacgr; Lindau (B) Nf. 667Ö 27892U(BLJt 733 204 42) patrl'lindau ■ '· .' , ; ■; yolfsbirjk, Llridkji (B) Nf, 51720000 (BLZ 7/l5 901 20) its center contact (12) is connected to the other connection (14) of the power supply, and its changeover contacts are each connected to the respective excitation coil (6,7) of the relays (22,23). 2. Control circuit according to claim 1, characterized in that the changeover switch (12) is single-pole. 3. Control circuit according to claim 1 or 2, characterized in that the respective working contacts (20, 21) of the relays are connected via lines (10, 11) to the other connection (14) of the power supply (Fig. 1). 4. Control circuit according to one of claims 1-3, characterized in that the respective working contacts (20, 21) of the relays are connected via lines (10, 11) to the lines (8, 9) which lead to the changeover contacts of the changeover switch (12) reversing the direction of rotation of the motor (1).