JPH026917B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to electric blinds that raise and lower slats and screens by transmitting the rotation of a DC motor to a rotating body for lifting and lowering blinds through a gear mechanism that does not have an automatic stop function. This invention relates to improvements in stopping devices.

[Prior Art] It is well known that a direct current motor placed inside a small blind can be used to raise and lower the screen of a roller blind or to tilt the slats of a Venetian blind. Because the internal space of both the roll pipe of a roll blind and the head box of a Venetian blind, in which the motor is installed, is narrow, the reduction mechanism of the motor is usually replaced with a worm gear mechanism in which the input and output shafts are orthogonal, making it difficult to fit compactly. A spur gear mechanism is used in which the input and output shafts are parallel and compact. With a worm gear mechanism, when the motor stops rotating, even if the rotating body of the blind tries to continue rotating due to the inertia, the rotation due to the inertia is prevented by an automatic stopping action, but with a spur gear mechanism, rotation due to the inertia is prevented. It reaches the motor and tries to rotate the motor. The motor of conventional electric blinds is
As disclosed in JP-A No. 59-68493, when the voltage supply circuit is cut off, a smoothing capacitor is simply connected in parallel to the DC motor, and there is virtually nothing to electrically stop the rotation of the motor. ,
The motor is rotated until the inertia of the rotating body is less than the mechanical resistance of the motor. This was the cause of the problem that even if the motor was stopped during the lowering of the blind, the screen and slats continued to lower. Also, in the case of blinds with a large weight, if you touch the bottom bar for some reason,
There was also the problem that the torque due to its own weight became greater than the mechanical resistance of the motor, etc., and the slats and screens suddenly began to descend while they were stopped.

[Problems to be Solved by the Invention] An object of the present invention is to provide an electric blind stopping device that can solve the above-mentioned problems. In other words, in a blind that transmits the rotation of the motor to the blind rotating body via a spur gear mechanism, if the motor stops rotating while the slats or screen are lowering, the slats or screen may continue to descend, or the blind may be accidentally damaged. The object of the present invention is to provide a stopping device in which there is no fear that a stopped screen or slat will start to descend even if the screen or slats are touched.

[Means for Solving the Problems] In order to achieve the above object, the characteristic means of the device of the present invention is that a braking circuit consisting of a diode is connected to both terminals of a DC motor that raises and lowers the blind. When the voltage supply to the motor is stopped, the weight of the blind tries to rotate the motor, and dynamic braking is applied.

The braking circuit consists of a first circuit that shorts both terminals of the motor via the first diode when the current to the motor is cut off, and a second diode and resistor that grounds the positive terminal when the motor stop button is pressed. It is desirable to provide a second circuit including the second circuit in parallel.

[Operation] When the voltage supply to the motor is stopped, the blind tries to rotate with inertia. When the blind is raised, the torque of the inertia and the blind's own weight are opposite, but when the blind is lowered, the direction of the inertia and the blind's own weight is the same, so the torque that tries to rotate the motor is large, and the motor is not rotated. Generates electromotive force. However, both terminals of the motor are short-circuited by a braking circuit that includes a diode, and the diode is in the forward direction of the electromotive force, so dynamic braking is applied to the rotation of the motor.
Rotation of the motor is blocked.

[Effect] As mentioned above, in the device of the present invention, a braking circuit consisting of a diode is connected in parallel to the motor,
The diode is set in the forward direction with respect to the voltage generated when the motor is rotated as a generator, so when the motor is stopped in the middle of lowering the blind, the relatively large inertia of the blind rotating body will be reduced. Even if an attempt is made to rotate the motor by acting on it, the motor cannot rotate because dynamic braking is applied. Therefore, when the motor is stopped during the lowering of the blind, the blind also stops instantaneously, which is an excellent effect that cannot be obtained with conventional blind stopping devices.
In addition, in the case of conventional blind stopping devices, if a stopped blind is subjected to its own weight or force in a downward direction, that force may rotate the motor and cause the blind to descend, causing an unexpected accident. In the device of the present invention, the motor cannot rotate even if its own weight or an external force that tries to lower the blind acts while the voltage supply to the motor is stopped, so the blind lowers at some timing. Such accidents can also be prevented.

[Example] The apparatus of the present invention will be described based on an example shown in the drawings.

As shown in FIG. 2, a DC motor M with a spur gear reducer of the electric Venetian blind is installed in a head box 10, and its output shaft is directly connected to a rotating shaft 15 which is a rotating body for opening and closing the blind. A drum 16 on which a lifting tape 14 for suspending the bottom bar 11 is wound, and a drum 17 on which a ladder cord for tilting the slat 12 is wound are attached to the rotating shaft 15 via a clutch 18. When the motor M rotates the rotating shaft 15 in one direction, the slat 12 is tilted in one direction by the ladder cord 13. When the motor M rotates the rotating shaft 15 in one direction, the slat 12 is tilted in one direction by the ladder cord 13. When the motor M rotates the rotating shaft 15 in the other direction, the slat 12 is tilted in one direction by the lifting tape 14 when it is fully closed. 13
When the lid is tilted in the other direction and the lid is fully closed, it is raised by the lifting tape 14, but these structures are the same as those of the conventional one.

As shown in Figure 1, 100V AC is transformed into 25V and 5V through transformer T, and diode D5,
A rectifier circuit including D6 supplies the motor as a DC voltage. When the low speed switch S1 is turned to the down side or the opposite up side, the relay coil RL2 or RL
Not only is relay coil RL1 turned on for a certain period of time, selection switch RLS is turned on.
1 switches to the 5V side. Therefore, during tilting before raising or lowering the slat, a voltage of 5V is applied to the motor M.
The motor rotates at a slow speed and the slat tilts slowly. When the down button SD or up button SU is pressed, relay coil RL2 or RL3 is turned on, and the selection switch RLS1 has returned to 25V, so a voltage of 25V is supplied to the motor M, and the motor M rotates at high speed. The slats rise or fall rapidly. The circuit has upper and lower limit switches.
When ULS, LLS are inserted and the blind reaches its upper or lower limit, the current to motor M is interrupted.
Also, press the pushbutton ST while the slat is rising or falling.
When you press , relay coil RL2 or RL3 is turned off, so press selection switch RLS2 or relay switch.
RLS3 is cut off and the current to motor M is cut off.
If the current to the motor M is cut off while the slat is rising, the torque due to the slat's own weight is in the opposite direction to the inertia, so there is almost no rotation due to the inertia, and the motor is rotated in the downward direction by the slat's own weight after stopping. Furthermore, if the current to the motor M is cut off when the slat is lowered, the torque due to the slat's own weight is in the same direction as the inertia, so the motor is rotated in the direction in which the slat is lowered without stopping. In this way, in either case, the motor M is rotated in the direction in which the slats descend, so that an electromotive force having the symbol shown in FIG. 1 is generated at the terminals of the motor M.

If the upper limit switch ULS goes out during ascent, the third
As shown in the figure, both terminals A and B of the motor M are short-circuited via a first diode D1. Even when the lower limit switch LLS is turned off during the descent, the selection switch returns to the same state, and the motor M is dynamically braked to prevent its rotation.

When the stop button ST is pressed during descent, the second relay switch is first turned on, so as shown in Figure 4, the positive side terminal A of the motor M is connected to the second diode D.
2 and a second circuit including a resistor R to ground. Then, as shown in FIG. 5, the first diode D1
A first circuit is connected to both terminals A and B of the motor M. Therefore, dynamic braking of the rotation of the motor M is applied more effectively. The same situation will occur if the low speed switch is returned during low speed descent using the low speed switch.

When the stop push button is pressed during ascent, or when the low speed switch is returned during low speed ascent using the low speed switch, the second circuit is grounded, but before the slat reverses due to its own weight, the selection switch RLS2 returns.
Since the limit switch RL3A is turned on, the state shown in FIG. 5 is reached.

Note that when the low speed switch S1 is turned to the lower side, current flows not only to the motor but also to the second circuit, but the current flowing through the second diode D2 and the resistor R is small.

Even if the dead weight of the blind rotating body is large, the rotation of the motor is prevented by dynamic braking, so if the voltage supply to motor M is interrupted by operating the limit switches ULS, LLS, low speed switch S1, and push button ST, the slat The descent also stops instantly.
Also, even if a force in the direction of lowering the slat acts on the stopped blind and attempts to rotate the motor, the rotation of the motor will be blocked.
Accidents such as touching the blind while the motor is stopped and causing the slat to start descending will not occur.

Although a Venetian blind is shown as an example, it goes without saying that the device of the present invention can also be applied to a roll blind.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram of a Venetian blind equipped with the device of the present invention, and FIG. 2 is a front view showing essential parts of the Venetian blind of FIG. 1. 3 to 5 are circuit diagrams showing dynamic braking of the motor. In the figure, reference numeral 15 is a rotating shaft (rotating body for opening and closing blinds), M is a motor (alternating current), A and B are motor terminals, R is a resistance, ST is a stop push button, D1,
D2 indicates first and second diodes, RL3A indicates a first relay switch, and RL1A indicates a second relay switch.

Claims (1)

[Scope of Claims] 1. A DC motor that raises and lowers a blind, a switch that cuts off voltage supply to the motor, and a first diode that connects both terminals of the motor when the voltage supply to the motor is interrupted by the switch. An electric blind stopping device comprising a braking circuit that is short-circuited through a brake circuit, wherein the first diode is in a forward direction with respect to a voltage generated when the motor is rotated in a blind lowering direction. 2 The switch that cuts off the voltage supply to the motor includes a manual stop button, and the braking circuit is a circuit that grounds the positive voltage terminal generated when the motor is rotated in the blind downward direction via a second diode and a resistor. An electric blind stopping device according to claim 1, characterized in that it includes: