JP2001055880A - Motor-driven opening/closing device for building, to be used together with spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor-driven opening/closing device for a building, to be used together with a spring, which can detect an obstacle or a limit position by detecting mechanical load applied from a motor to a driven part. SOLUTION: An endless drive chain 12 is extended over the output side sprocket 15 and the drive side sprocket 8 of a motor. The motor is mounted on a movable plate 11, which is energized in the direction in which tension is applied to the drive chain 12 by an adjusting spring 13. During the normal rise and fall of a shutter curtain, the spring constant of the adjusting spring 13 is adjusted to be greater than a mutually pulling force between the output side sprocket 15 and the drive side sprocket 8, so that the movable plate 11 does not move. At an obstacle or a limit position, overload is applied and the movable plate 11 slides to actuate a microswitch 10 to stop the motor 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction type electric opening / closing device using a spring such as an electric construction shutter.

[0002]

2. Description of the Related Art Conventionally, in an electric switch for architectural use in combination with a spring in an electric shutter or the like, as a method of detecting an obstacle or a limit position based on a load of a motor for driving the electric switch, a change in rotation speed (or A method of detecting a change in load by detecting an electrical characteristic such as a change in rotation speed or a change in current value (or a change in voltage value) is used. However, in this method, the electric characteristics of the motor are
Since it changes due to fluctuations in temperature, frequency, voltage, etc., it is necessary to evaluate the detection output with a safety factor in anticipation of the amount of change, and there is a problem that it is difficult to perform highly accurate detection. .

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and detects a mechanical load applied to a driven portion from a motor without using a method for detecting electric characteristics of the motor. Accordingly, it is an object of the present invention to provide a spring-operated electric switchgear for building which can detect an obstacle and a limit position.

[0004]

According to a first aspect of the present invention, there is provided a winding drum for winding an opening / closing body for opening and closing an opening, a fixed shaft coaxial with the winding drum, and one end of the winding drum. A balance spring attached to the take-up drum and the other end attached to the fixed shaft, a drive sprocket for driving the take-up drum, a drive chain meshing with the drive sprocket, and a motor for biasing the drive chain The motor is fixed to a movable plate movably provided with respect to the drive sprocket, and meshes with the drive chain attached to an output shaft thereof. The movable plate has an output side sprocket, and the movable plate is constantly driven by a spring that applies a biasing force in a direction of applying tension to the drive chain. It is energized, and is characterized in that the detection switch for detecting the movement of the movable plate are provided.

According to a second aspect of the present invention, there is provided the electric spring-operated open / close device according to the first aspect, wherein a pin is provided on one of the substrate supporting the movable plate and the movable plate, and the other is provided on the other side. A guide hole for guiding the pin.

According to a third aspect of the present invention, there is provided a winding drum for winding an opening / closing body for opening and closing an opening, a fixed shaft coaxial with the winding drum, and one end attached to the winding drum. A balance spring having an end attached to the fixed shaft, a drive sprocket for driving the winding drum, and a drive chain meshing with the drive sprocket;
In a spring-operated construction open / close device having a motor for biasing the drive chain, the motor is fixed to a fixed position with respect to the drive side sprocket and the drive chain attached to an output shaft thereof. The drive chain has a slack, and a spring that applies a biasing force in a direction to apply tension to the drive chain on both sides between the drive side sprocket and the output side sprocket. A detection switch which is always energized and which detects a movement of a path of the drive chain on both sides between the drive side sprocket and the output side sprocket is provided.

According to a fourth aspect of the present invention, there is provided the electric open / close device for a building with a spring according to the third aspect, wherein the drive chain by the urging force is provided on both sides between the drive sprocket and the output sprocket. A regulating member that regulates the movement of the inside of the path to the inside is provided.

According to a fifth aspect of the present invention, there is provided a winding drum for winding an opening / closing body for opening and closing an opening, a fixed shaft coaxial with the winding drum, and one end attached to the winding drum. A balance spring having an end attached to the fixed shaft, a drive sprocket for driving the winding drum, and a drive chain meshing with the drive sprocket;
In a spring-operated electric switchgear having a motor for biasing the drive chain, the motor is fixed at a fixed position with respect to the drive sprocket, and a gear is provided on an output shaft of the motor. The drive chain is driven via an idler member provided with a gear meshing with the gear and an intermediate sprocket meshing with the drive chain, and the idler member is provided movably with respect to the drive side sprocket. In addition, a detection switch is provided that is constantly urged by a spring that urges the output shaft toward the output shaft and that detects movement of the idler member.

According to a sixth aspect of the present invention, there is provided an electric switchgear for use with a spring according to any one of the first to fifth aspects, wherein the biasing force is adjustable. It is.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross-sectional view, as viewed from the front side, showing the outline of a winding portion when a spring-operated constructional opening / closing device of the present invention is applied to an electric shutter. In the figure, 1 is a winding drum, 2 is a fixed shaft, 3 is a wheel, 3a is a collar, 4 is a flat bar, and 5 is a balance spring.

A take-up drum 1 for taking up a shutter curtain is composed of a plurality of wheels 3 and a flat bar 4 connecting the wheels 3, and is rotatably supported on a fixed shaft 2. A collar 3a is attached to the wheel 3 at a portion where the wheel 3 is rotatably supported by the fixed shaft 2, and has a vibration-preventing action and also serves as a bearing structure. Although two flat bars 4 are provided in this example, three or more flat bars 4 may be provided. Further, a cylindrical plate-like body may be used instead of the flat bar 4. The balance spring 5 is provided around the fixed shaft 2, and has one end attached to the wheel 3 and the other end attached to the fixed shaft 2.
The load increases as the shutter curtain descends,
As the shutter curtain descends, the energy stored in the balance spring 5 is increased to achieve balance.
The difference between the load on the shutter curtain and the energy stored in the balance spring is covered by the motor.

FIGS. 2 to 7 are views for explaining a first embodiment in which a spring-operated construction type electric switching device of the present invention is applied to an electric shutter, and FIG. 2 is a winding drum. 3 is a schematic diagram viewed from the side (the motor is shown by a dashed line), FIG. 3 is a schematic diagram of FIG. 2 viewed from the front, FIG. 4 is a front view showing an overloaded state, and FIG. (A) is a plan view, (B) is a side view,
FIG. 6 is a component diagram of the movable plate, (A) is a plan view,
(B) is a side view as viewed from the B direction, (C) is a side view as viewed from the C direction, (D) is a cross-sectional view taken along the line DD, FIG. 7 is a component diagram of the spring adjustment bracket, and (A) is FIG. 2B is a plan view, FIG. 2B is a side view seen from the B direction, and FIG. 1C is a side view seen from the C direction. In the figure, 6 is a motor plate, 6a is a fixing screw hole, 6
b is a long hole, 7 is a bracket, 8 is a driving sprocket,
9 is a motor, 9a is a motor mounting member, 10 is a micro switch, 11 is a movable plate, 11a is a round hole, 11b is a pin, 11c is a spring engagement hole, 12 is a drive chain, 13 is an adjustment spring, and 14 is spring adjustment. Metal fittings, 14a is a spring mounting terminal, 14b is a stopper,
14c is a wire, 14d is an adjustment bolt, 14e is a fixture, 14f is a lock nut, and 15 is an output sprocket. 2 and 4, only a part of the chain is shown, and the path of the chain is shown by a dashed line, and the motor is shown by a dashed line. In FIG. 3, the illustration of the chain is omitted.

The motor plate 6 is fixed to a bracket 7 and is connected to the take-up drum 1 by a driving sprocket 8.
Is rotatably mounted. Also, the motor plate 6
Micro switch 1 for outputting a stop signal of motor 9
0 is set. The bracket 7 is provided with a protrusion at a portion where the motor plate 6 is fixed, and the motor plate 6 is fixed to the bracket 7 with a gap by the protrusion. A movable plate 11 for mounting a motor is movably disposed in a gap between the plate 6 and the bracket 7, and the motor 9 is mounted on the movable plate 11 by a motor mounting member 9a.

The movable plate 11 includes a motor plate 6
A round hole 11a for escaping the protrusion of the bracket 7 corresponding to the fixing screw hole 6a is formed. The movable plate 11 has two pins 11 b protruding toward the motor plate 6. In this embodiment, the pin 11b
Is formed by drawing as shown in FIG. 6D, but a pin may be fixed as a separate member. The motor plate 6 is formed with two long holes 6b at positions corresponding to the pins 11a of the movable plate 11, and the pins 11a are inserted into the long holes 6b and guided, and the movable plate 11 slides. The restriction of the moving direction and the amount of movement of the movable plate 11 are restricted by the elongated holes 6b serving as guide holes.

Between the movable plate 11 and the motor plate 6, there is provided an adjusting spring 13 for constantly applying an urging force in a direction for applying a tension to the drive chain 12. The adjustment spring 13 has one end fixed to the spring locking hole 11 c of the movable plate and the other end attached to a spring mounting terminal of a spring adjustment fitting 14 fixed to the motor plate 6.

As shown in FIG. 7, the spring adjustment fitting 14 has a spring mounting terminal 14a at one end and a wire 14c having a stopper 14b attached at the other end, and an adjustment bolt 14
Adjusting bolt 1 so that it does not come out through the hollow hole of d
It is locked by a stopper 14b at the tip of 4d. The screw formed on the outer periphery of the adjustment bolt 14d is a fixing bracket 1
4e, and is fixed by a lock nut 14f. Loosen lock nut 14f and adjust bolt 1
4d, and adjust bolt 14 from fixing bracket 14e.
By moving d forward or backward, the urging force of the adjustment spring 13 (FIG. 2) can be adjusted.

An endless drive chain 12 is stretched between the output sprocket 15 and the drive sprocket 8 of the motor 9. The attractive force between the output sprocket 15 and the driving sprocket 8 of the motor 9 changes according to the mechanical load output by the motor 9. When the shutter curtain is normally moved up and down and stopped, the movable plate 11 is adjusted so that the spring constant of the adjustment spring 13 is larger than the attractive force between the output side sprocket 15 and the driving side sprocket 8. , The micro switch 1 does not move due to the urging force of the adjustment spring 13.
0 does not work.

If an obstacle is caught in the middle of the lowering of the shutter curtain, the load of the shutter curtain is applied to the obstacle, and the motor 9 tries to wind the balance spring, so that an overload is applied and the motor 9 outputs. The pulling force between the side sprocket 15 and the driving side sprocket 8 becomes larger than the spring constant of the adjustment spring 13, and the movable plate 11 slides so that the pin 11b of the movable plate 11 is aligned with the elongated hole 6b, and the micro switch is moved. By operating the motor 10, the motor 9 is stopped. This state is shown in FIG. The same applies to the lower limit stop of the shutter curtain.

The upper limit is stopped when the seat plate of the shutter curtain is locked in the lintel at the upper limit position.
Further, the overload is applied to further raise the shutter curtain, and the movable plate 11 slides to operate the microswitch 10 and stop the motor 9 in the same manner as in the case of the lowering. The micro switch 10
It is sufficient that the movement of the movable plate 11 can be detected, and it can be arranged at an appropriate location.

In this embodiment, the detection sensitivity of the overload when the shutter curtain is lowered and when the shutter curtain is raised is affected by the direction of the elongated hole 6b and the direction in which the adjustment spring 13 is attached. Therefore, a desired detection characteristic can be realized by those designs. In the case of FIG. 2, the detection sensitivity when the shutter is lowered is more sensitive than the detection sensitivity when the shutter is raised. Further, by adjusting the urging force of the adjustment spring 13 with the spring adjustment fitting 14, the overload detection force can be adjusted according to the load on the shutter curtain.

FIGS. 8 to 10 are views for explaining a second embodiment in which the spring-operated construction open / close device of the present invention is applied to an electric shutter. FIG. 8 shows a winding drum. 9 is a schematic diagram viewed from the side (the motor is shown by a dashed line), FIG. 9 is a schematic diagram of FIG. 8 viewed from the front, and FIG. 10 is a front view showing an overloaded state. In the figure, the same parts as those in FIGS. 10a and 10b are micro switches, 13
Reference numerals a and 13b denote adjustment springs, 16a and 16b denote drive chain regulating members, and 17a and 17b denote spring adjustment fittings. In FIGS. 8 and 10, the motor is shown by a chain line. In FIG. 9, illustration of the chain is omitted.

The motor plate 6 is fixed to a bracket 7 and is connected to the take-up drum 1 by a driving sprocket 8
Is rotatably mounted. Also, the motor plate 6
Above, the motor 9 is fixed by a motor mounting member 9a. Microswitches 10 a and 10 b for outputting a stop signal for the motor 9 are provided on the motor plate 6 on both sides of the drive chain 12 between the output sprocket 15 and the drive sprocket 8. When the output side sprocket 15 is driven to the descending side, the microswitch 10a installed on the side to which the drive chain 12 is applied with the driving tension outputs a stop signal when the load is overloaded at the time of descending. When the side sprocket 15 is driven to the ascending side, the microswitch 1 installed on the side to which the driving tension is applied to the drive chain 12
0b outputs a stop signal when an overload occurs during ascending.

An endless drive chain 12 is stretched between the output sprocket 15 of the motor 9 and the drive sprocket 8, and the drive chain 12 is elongated to have a slight slack. The drive chain 12 is pressed from the outside toward the inside by two right and left paired adjustment springs 13a and 13b, and passes through a path bent inward. Drive chain regulating members 16a and 16b are provided inside the drive chain 12 so as to face the portions pressed by the adjustment springs 13a and 13b. Although the drive chain regulating members 16a and 16b are not necessarily required, by providing them, the tension applied to the drive chain 12 by the pressing of the drive chain 12 by one of the adjustment springs causes the other adjustment spring to adjust the tension. The spring does not affect the portion where the drive chain 12 is pressed.

According to the mechanical load output by the motor 9,
The tension applied to the drive chain 12 changes. During normal lifting and lowering and stopping of the shutter curtain, depending on the direction of rotation, the tension applied to the drive chain 12 adjusts the path of the drive chain 12 that is bent inward rather than the force that tends to become a straight path. Spring 13
Since the spring constant of a or 13b is adjusted to be large, the drive chain 12 transmits the driving force from the output sprocket 15 to the drive sprocket 8 in a bent state, and the microswitch 10a or 10b Do not work.

If an obstacle is caught in the middle of the lowering of the shutter curtain, the load of the shutter curtain is applied to the obstacle, and the motor 9 attempts to wind the balance spring, so that an overload is applied and the motor 9 is driven. Due to the tension applied to the chain 12, the force for straightening the drive chain 12 becomes larger than the spring constant of the adjusting spring 13a, and the micro switch 10a is operated by the drive chain 12 to stop the motor 9.
This state is shown in FIG. The same applies to the lower limit stop of the shutter curtain. In the upper limit stop, in a state where the seat plate of the shutter curtain is locked in the lintel at the upper limit position, the motor 9 is overloaded by further trying to wind up the shutter curtain, and in the same manner as in the case of descent, the motor 9 is moved to the opposite side. The tension applied to the drive chain 12 increases, and the micro switch 10b is operated to stop the motor 9.

The spring adjusting brackets 17a and 17b adjust the positions of the ends of the adjusting springs 13a and 13b opposite to the ends of the adjusting springs 13a and 13b which are in contact with the drive chain 12.
This is for adjusting the biasing force of the adjustment springs 13a and 13b, and by this adjustment, the overload detection force can be adjusted according to the load on the shutter curtain.

The drive chain regulating members 16a, 16
Although b uses a rotatable wheel, it may be a wheel with a collar so that it does not come off from the drive chain 12, or it may be meshed with the drive chain 12 using a sprocket. A portion of the adjusting springs 13a, 13b against which the drive chain 12 is pressed is also provided with a rotatable wheel, a flanged wheel, a sprocket, or the like attached to the distal end thereof.
May be pressed. Although a linear spring is used, the drive chain 12 may be pressed by a rotatable wheel, a flanged wheel, a sprocket, or the like using a coil spring or the like.

The drive chain 12 is pressed inward by adjusting springs 13a and 13b.
The adjustment springs 13a and 13b may be arranged inside to press the drive chain 12 outward. The microswitches 10a and 10b only need to be able to detect a change in the path of the drive chain 12, and can be arranged at appropriate locations.

FIGS. 11 to 13 are views for explaining a third embodiment in which the spring-operated constructional open / close device of the present invention is applied to an electric shutter.
1 is a schematic view of the side view with the winding drum removed, FIG.
2 is a schematic view of FIG. 11 viewed from the front side, and FIG. 13 is a front view showing an overload state. In the figure, the same parts as those in FIGS. 17 is a spring adjusting bracket, 18 is an idler member, 18a is a gear, 1
8b is a sprocket, 19 is a mounting member, 20 is a support shaft,
21 is an output gear. In FIGS. 11 and 13, only a part of the chain is illustrated, and the path of the chain is illustrated by a dashed line, and the motor is illustrated by a dashed line. In FIG. 12, the illustration of the chain is omitted.

The motor plate 6 is fixed to a bracket 7 and is connected to the winding drum 1 by a driving sprocket 8.
Is rotatably mounted. Also, the motor plate 6
An idler member 18 is movably mounted thereon, and a microswitch 10 that outputs a stop signal of the motor 9 includes:
It is installed at a position where the movement of the idler member 18 can be detected. The motor 9 is fixed on the motor plate 6 by a motor mounting member 9a.

The idler member 18 is connected to the gear 18a and the sprocket 18b, and is interposed between the driving sprocket 8 and the output shaft of the motor 9. A mounting member 19 for mounting the idler member 18 is rotatably supported by a support shaft 20 fixed to the motor plate 6. The gear 18 a of the idler member 18 is pressed by an adjustment spring 13 that urges the mounting member 19 so as to mesh with the output gear 21 mounted on the output shaft of the motor 9.

The sprocket 18 connected to the gear 18a
b and the drive sprocket 8 with the endless drive chain 1
Two have been bridged. In accordance with the mechanical load output by the motor 9, the tension applied to the drive chain 12 changes and the force applied from the output gear 21 to the gear 18a changes. When the shutter curtain is normally moved up and down, mechanical output is transmitted from the output gear 21 to the gear 18a, and transmitted from the sprocket 18b to the drive sprocket 8. When the shutter curtain is normally moved up and down and stopped, the idler member 18 is pressed against the output gear side of the motor 9 by the adjustment spring 13, and the microswitch 10 does not operate.

If an obstacle is caught in the middle of the lowering of the shutter curtain, the load of the shutter curtain is applied to the obstacle, and the motor 9 tries to wind the balance spring, so that an overload is applied and the motor 9 outputs. The force transmitted from the side gear 21 to the gear 18a is increased, and the force for pushing the output side gear 21 is adjusted by the adjustment spring 1
3, the output side gear 21 is disengaged from the gear 18a, and the mounting member 19 rotates counterclockwise in FIG.
To stop the motor 9. This state is shown in FIG.
3 is shown. The same applies to the lower limit stop of the shutter curtain.

The upper limit stop is performed when the seat of the shutter curtain is locked in the lintel at the upper limit position.
Is overloaded to further wind up the shutter curtain, and the mounting member 19
Rotates to operate the microswitch 10 to stop the motor 9. The microswitch 10 only needs to be able to detect the movement of the idler member 18, and can be arranged at an appropriate location.

The spring adjusting member 17 adjusts the biasing force of the adjusting spring 13 by adjusting the position of the end of the adjusting spring 13 opposite to the end that presses the mounting member 19. The overload detection force can be adjusted according to the load on the shutter curtain.

In the above embodiment, the electric shutter using the shutter curtain constituted by the slats has been described. However, the present invention can be applied to an electric shutter such as a shutter using a panel. Can be applied to an electric power switch for construction using a spring.

[0037]

As is apparent from the above description, according to the present invention, in a spring-operated electric switchgear for construction use, a failure is detected by detecting a mechanical load applied to a driven part from a motor. There is an effect that an object and a limit position can be detected.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a winding unit when a spring-operated electric building switchgear of the present invention is applied to an electric shutter.

FIG. 2 is a view for explaining a first embodiment in a case where the spring-operated electric building switchgear of the present invention is applied to an electric shutter, in which a winding drum is removed and viewed from a side. It is a schematic diagram.

FIG. 3 is a schematic view of FIG. 2 as viewed from the front side.

FIG. 4 is a front view showing an overload state.

5A is a plan view of a part of a motor plate, FIG.
(B) is a side view.

FIG. 6 is a part view of the movable plate, (A) is a plan view,
(B) is a side view as viewed from the B direction, (C) is a side view as viewed from the C direction, and (D) is a cross-sectional view along the line DD.

FIGS. 7A and 7B are part views of the spring adjustment fitting, in which FIG. 7A is a plan view, FIG. 7B is a side view seen from the B direction, and FIG. 7C is a side view seen from the C direction.

FIG. 8 is a view for explaining a second embodiment in which the spring-operated architectural electric switchgear of the present invention is applied to an electric shutter, in which the winding drum is removed and viewed from the side. It is a schematic diagram.

FIG. 9 is a schematic view of FIG. 8 as viewed from the front side.

FIG. 10 is a front view showing an overload state.

FIG. 11 is a view for explaining a third embodiment in which the spring-operated architectural electric switchgear of the present invention is applied to an electric shutter, in which the winding drum is removed and viewed from the side. It is a schematic diagram.

FIG. 12 is a schematic view of FIG. 11 as viewed from the front side.

FIG. 13 is a front view showing an overload state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Winding drum, 2 ... Fixed shaft, 3 ... Wheel, 3a ... Color, 4 ... Flat bar, 5 ... Balance spring,
6 ... motor plate, 6a ... fixed screw hole, 6b ... long hole,
7 bracket, 8 drive sprocket, 9 motor, 9a motor mounting member, 10, 10a, 10b micro switch, 11 movable plate, 11a round hole,
11b: Pin, 11c: Spring locking hole, 12: Drive chain, 13, 13a, 13b: Adjusting spring, 1
4 ... Spring adjustment fitting, 14a ... Spring mounting terminal, 14b ... Retaining, 14c ... Wire, 14d ... Adjustment bolt, 14e ... Fixing fitting, 14f ... Lock nut, 1
Reference numeral 5: output side sprocket, 16a, 16b: drive chain regulating member, 17, 17a, 17b: spring adjusting bracket, 18: idler member, 18a: gear, 18b: sprocket, 19: mounting member, 20: support shaft, 21 ... Output gear.

Claims (6)

[Claims] 1. A winding drum for winding an opening / closing body for opening and closing an opening, a fixed shaft coaxial with the winding drum, and one end attached to the winding drum and the other end attached to the fixed shaft. A spring for balance, a driving sprocket that drives the winding drum, a driving chain that meshes with the driving sprocket, and a spring combined use type electric opening / closing device having a motor that biases the driving chain. The motor is fixed to a movable plate movably provided with respect to the drive sprocket, and has an output sprocket that meshes with the drive chain attached to an output shaft of the motor. The chain is always urged by a spring that applies an urging force in the direction of applying tension to the chain, and moves the movable plate. An electric switchgear for construction using springs, which is provided with a detection switch for detecting. 2. The movable plate according to claim 1, wherein a pin is provided on one of the substrate supporting the movable plate and the movable plate, and a guide hole for guiding the pin is provided on the other. An electric switchgear for construction using springs. 3. A winding drum for winding an opening / closing body for opening and closing an opening, a fixed shaft coaxial with the winding drum, and one end attached to the winding drum and the other end attached to the fixed shaft. A spring for balance, a driving sprocket that drives the winding drum, a driving chain that meshes with the driving sprocket, and a spring combined use type electric opening / closing device having a motor that biases the driving chain. The motor is fixed at a fixed position with respect to the drive sprocket, and has an output sprocket that meshes with the drive chain attached to the output shaft of the motor. On both sides between the sprocket and the output side sprocket, a direction for applying tension to the drive chain is provided. A spring which is always urged by a spring for applying a force and which is provided with a detection switch for detecting a movement of a path of the drive chain on both sides between the drive side sprocket and the output side sprocket, respectively. A combined electric switch for construction. 4. A control member provided on both sides between the driving sprocket and the output sprocket, for restricting movement of the driving chain inward of the path by the urging force. An electric switchgear for construction using a spring as described in the above. 5. A winding drum for winding an opening / closing body for opening and closing an opening, a fixed shaft coaxial with the winding drum, and one end attached to the winding drum and the other end attached to the fixed shaft. A spring for balance, a driving sprocket that drives the winding drum, a driving chain that meshes with the driving sprocket, and a spring combined use type electric opening / closing device having a motor that biases the driving chain. An idler member having the motor fixed to a fixed position with respect to the drive side sprocket, a gear provided on an output shaft of the motor, and a gear meshing with the gear and an intermediate sprocket meshing with the drive chain attached thereto; The drive chain is configured to drive the drive chain through the drive sprocket. A spring that is movably provided, is always urged by a spring that urges the output shaft, and is provided with a detection switch that detects movement of the idler member. A combined electric switch for construction. 6. The electric power switch according to claim 1, wherein the biasing force is adjustable.