JPS6237917Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an automatic stopping device for electric Venetian blinds.

When the bottom bar of the blind falls to its lower limit or hits an obstacle, the motor must stop rotating immediately, but conventional devices press one end of the lever that engages the limit switch against the lifting tape. When the bottom bar reached its lower limit or hit an obstacle and the tape loosened, a lever turned off the limit switch and stopped the motor. However, in order for the lever to come into contact with the tape, the lever must be extended outside the top box, and because it is constantly in frictional contact with the tape, the lever may become deformed and the tape may wear out, making operation uncertain. It was hot.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device for operating a limit switch without contacting the tape to solve the above-mentioned problems. To achieve the above object, the gist of the present invention is to rotatably support a rudder drum in a holder in a head box, fit a tape drum to the rudder drum so that it can rotate relative to the rudder drum, and attach a stopper to the rudder drum so that it can move in and out in the radial direction. After installation, the cam of the tape drum is fitted into the cam groove provided in the stopper, and a spring is interposed between the tape drum and the ladder drum to press the tape drum in the winding direction. When the tape loosens, the tape drum reverses and closes the stopper. The device is provided with a lever that protrudes and engages with the protruding stopper to operate the limit switch.

The apparatus of the present invention will be explained based on the embodiments shown in the drawings. As shown in FIGS. 1 and 2, a drum holder 1 and a switch base 7 are fixed adjacent to each other in a head box 15 of a blind, a ladder drum 17 is rotatably supported on the holder, and a tape drum is attached to the ladder drum. 2 so that they can rotate relative to each other. A rise stop limit switch 12, a fall stop limit switch 9, and levers 13 and 10 for operating the switches are attached to the switch base 7. A drive shaft 14 is passed through the rudder drum 17 so as to be integrally rotatable, and is connected to an output shaft of a motor via a transmission device (not shown). A stopper 5 is attached to the cam portion 8 of the ladder drum 17 that is in contact with the tape drum 2. A tape 3 is wound around a tape drum 2, and a ladder cord is hung around a ladder drum 17 via a ladder ring 6. The tape 3 passes through the slats 16 and is secured to the bottom bar 11, and the ladder cord 4 supports each slat 16.

As shown in FIG. 3, the stopper 5 is fitted into the cam portion 8 of the rudder drum 17 so as to be freely retractable in the radial direction.
A circular arc groove 21 is formed on both sides of the circular groove 21.
Insert the coil spring 18 into one of the two. A cam 19 and a protrusion 20 are provided on the tape drum 2 to fit into a cam groove 22 of a stopper 5 and an arcuate groove 21 of a cam part 8.

Next, a description will be given of automatic stopping of raising and lowering the blind using the device of the present invention. When the bottom bar hangs down freely, whether the blind is moving up or down or stopped, the bottom bar's own weight is applied to the tape 3, causing tension and exerting a moment on the tape drum 2 in the counter-winding direction. Therefore, as shown in FIG. 4, the cam 19 is located at the upper end of the cam groove 22.
Therefore, the stopper 5 retracts and does not engage with the lever 10, and the limit switch 9 remains turned on.If the motor is rotating, the blind continues to move up and down, but if it is stopped, it continues to move up and down. The blinds also remained stopped in that position. If the bottom bar hits an obstacle or is completely lowered while the blind is lowering, the tape 3 becomes loose as shown in FIG. When the tape 3 loosens, the moment that rotates the tape drum 2 in the counter-winding direction disappears, and the spring 18 in the arcuate groove 21 pushes the protrusion 20 to rotate the tape drum 2.
Since the cam 19 is rotated in the winding direction, the cam 19 is rotated in the cam groove 22.
Move to the lower end of and advance stopper 5. As a result, when the rudder drum 17 rotates and the stopper 5 comes to the lower side, the stopper 5 pushes down the lever 10,
Turn off limit switch 9. As shown in FIG. 6, when the limit switch 9 is turned off, the motor is turned off and stopped, so that the blind automatically stops lowering.

When the blind is raised to its upper limit and the uppermost slat 16 pushes up the lever 13, the limit switch 12 is turned off and the motor is stopped, so that the raising of the blind is automatically stopped.

As mentioned above, the device of the present invention automatically turns off the limit switch to stop the blind from descending when the blind descends to the lower limit or is blocked by an obstacle while descending, thereby preventing accidents. can be prevented. The lever that operates the limit switch is located inside the head box.
There is no contact with the tape at all, and there is no contact with the stopper except when the tape is loosened, so the lever will not be deformed or the tape will wear out due to the lever.

[Brief explanation of the drawing]

1 and 2 are a partially cutaway top view and front view of a blind equipped with a device according to an embodiment of the present invention, and FIG. 3 shows the tape drum and ladder drum of FIG. 1. The schematic assembly view, FIG. 4, is a sectional view taken along the line -- in FIG. 2, showing the state of the cam when the tape is tensioned. FIG. 5 is a diagram corresponding to FIG. 4 when the tape is loosened, and FIG. 6 is an electric circuit diagram showing the operation of the limit switch. 1: Drum holder, 2: Tape drum, 3: Tape, 5: Stopper, 8: Cam section, 9: Limit switch, 10: Lever, 14: Drive shaft, 17:
Rudder drum, 18: Spring, 19: Cam, 20:
Protrusion, 21: Arc groove, 22: Cam groove.

Claims (1)

[Claims for Utility Model Registration] 1. A drive shaft from a motor is rotatably passed through a rudder drum bearing a bearing on a drum holder, a tape drum is relatively rotatably fitted to the rudder drum, and a stopper is mounted on the rudder drum in a radial direction. The cam of the tape drum is fitted into the cam groove of the stopper, and a spring is provided between the tape drum and the ladder drum to press the tape drum in the winding direction, so that when the stopper advances, it A lever is provided at an engaging position, and a limit switch of an electric circuit when the motor is lowered is opened and closed via the lever, and when the tape is loosened and the tape drum rotates relatively in the winding direction, the cam moves to the stopper. An automatic stop device for an electric Venetian blind, characterized in that the limit switch is turned off by advancing the limit switch. 2 A stopper is attached to the cam part of the ladder cord so that it can move forward and backward in the radial direction, arcuate grooves are provided on both sides of the cam part, a protrusion that fits into the arcuate groove is provided on the tape drum, and a spring is inserted into one of the arcuate grooves. The automatic stopping device for an electric Venetian blind according to claim 1, wherein the tape drum is pressed in the tape winding direction.