Patent Description:
As a device that serves to control opening and closing of a damper, for example, there is the damper opening/closing device disclosed in <CIT>.

Such a damper opening/closing device is equipped with an opening/closing circuit unit in which there are formed a charging circuit for accumulating an electric charge in an electrical power storage means, and a discharging circuit for discharging the electric charge accumulated in the electrical power storage means, and a relay that switches to either one of the charging circuit or the discharging circuit, in accordance with a connected state of the opening/closing circuit unit and an external power source.

When the opening/closing circuit unit and the external power source are in an electrically connected energized state, the relay switches to the charging circuit, and an electric charge is accumulated in the electrical power storage means. Further, when the opening/closing circuit unit and the external power source are electrically disconnected, the relay discharges the electric charge that was accumulated in the electrical power storage means by the discharging circuit, and supplies the electric charge to a solenoid to drive a plunger of the solenoid, and by a damper opening/closing mechanism being operatively coupled to the plunger, the damper is changed from an open state into a closed state.

<CIT> describes a damper opening/closing device for an air conditioning duct to be used in a room which requires isolation in the event of a disaster.

However, in the damper opening/closing device disclosed in <CIT>, it is necessary for the electric charge to be accumulated in the electrical power storage means during a period in which electrical power is being supplied from the external power source. Therefore, the charging circuit for accumulating the electric charge, the electrical power storage means for accumulating the electric charge, and the discharging circuit for discharging the electric charge from the electrical power storage means at the time of a power failure are required.

Further, in the above-described damper opening/closing device, in the case of there being one electrical power storage means, it becomes impossible for the damper to be closed if the electrical power storage means has become damaged. This problem is solved by connecting a plurality of such electrical power storage means in parallel, but a concern arises in that the circuit system may become complex.

Further, if the amount of electric charge stored in the electrical power storage means is small, it is not possible to secure sufficient energy to close the damper, and there is a concern that the damper cannot be closed.

The present invention has been devised with the aim of solving the aforementioned problems, and has the object of providing a damper opening/closing device which, even in the case that supply of electrical power from an external power source is cut off, is capable of closing an air supply port or the like without using an electrical power storage means or the like, and in addition, is capable of being returned to its initial open state in the case that supply of electrical power from the external power source is restarted.

The damper opening/closing device according to the present invention is installed in an opening used for air conditioning, and is set out in claim <NUM>.

In accordance with the damper opening/closing device according to the present invention, even in the case that supply of electrical power from the external power source is cut off, the damper opening/closing device is capable of closing the air supply port or the like without using an electrical power storage means or the like, and in addition, is capable of being returned to its initial open state in the case that supply of electrical power from the external power source is restarted.

Hereinafter, an exemplary embodiment of a damper opening/closing device according to the present invention will be described with reference to <FIG>.

As shown in <FIG>, a damper opening/closing device <NUM> according to the present embodiment is installed, for example, in an opening <NUM> such as an air supply port installed on the floor surface of a container or the like.

The damper opening/closing device <NUM> includes a base platform <NUM> having a frame portion <NUM> mounted so as to surround the opening <NUM> within the floor surface, an opening/closing lid <NUM> that is installed to be capable of rotating with respect to the base platform <NUM> and that opens and closes the opening <NUM>, a retention mechanism <NUM> fixed to the base platform <NUM>, and a return mechanism <NUM>.

In addition to the above-described frame portion <NUM>, the base platform <NUM> integrally includes a pedestal <NUM>, which is installed adjacent to one side of the frame portion <NUM>.

The opening/closing lid <NUM> is formed, for example, by a metal plate, and with a sufficient size so as to close the opening <NUM>. In the example shown in <FIG>, since the opening <NUM> has a rectangular shape when viewed from above, the opening/closing lid <NUM> is formed in a rectangular shape in the same manner as the opening <NUM>. Of course, depending on the shape of the opening <NUM>, the shape of the opening/closing lid <NUM> may be a circular shape, an elliptical shape, a track shape, a polygonal shape, or the like. Moreover, such a track shape is a shape that is made up from two opposing semicircular portions, and two parallel straight line portions connecting the two semicircular portions. Further, a locked metal fixture <NUM>, which is locked and fixed by the retention mechanism <NUM>, is provided on an upper part of the opening/closing lid <NUM>.

The retention mechanism <NUM> retains the opening/closing lid <NUM> and places the opening <NUM> in the open state during a period in which supply of electrical power from an external power source or the like is being carried out, and releases retention of the opening/closing lid <NUM> when the supply of electrical power is stopped.

More specifically, as shown in <FIG> and <FIG>, the retention mechanism <NUM> includes a motor base <NUM>, and an electromagnetic chuck <NUM> fixed to a distal end portion of the motor base <NUM>. The motor base <NUM> includes, on the base platform <NUM>, two metal plates (a first metal plate 32A and a second metal plate 32B: see <FIG>) installed in an L-shape when viewed from above. Both the first metal plate 32A and the second metal plate 32B are installed so that plate surfaces thereof extend in a vertical direction, in other words, so that the plate surfaces are oriented along a horizontal direction. The first metal plate 32A is installed on the base platform <NUM>, and the second metal plate 32B is installed from the base platform <NUM> to a location above the opening/closing lid <NUM>. However, the second metal plate 32B is not fixed to the opening/closing lid <NUM>. Further, a part of a lower portion of the second metal plate 32B is removed or cut off, so as not to interfere with an opening operation of the opening/closing lid <NUM>.

In addition, a mounting metal fixture <NUM> used for mounting the electromagnetic chuck <NUM> and having a U-shaped cross section is attached to the plate surface of the second metal plate 32B, and the electromagnetic chuck <NUM> is attached to a distal end portion of the mounting metal fixture <NUM>. Further, a retaining metal fixture <NUM> is rotatably attached by a support shaft <NUM> to the mounting metal fixture <NUM>. The retaining metal fixture <NUM> includes an attracted site 36a facing an attracting surface of the electromagnetic chuck <NUM>, and a locking site 36b having, for example, an L-shaped cross section, and integrally provided on a distal end of the attracted site 36a.

In addition, as shown by the two-dot-dashed line in <FIG>, in a state in which the mounting metal fixture <NUM> is retained (attracted) by the electromagnetic chuck <NUM>, a portion of the locked metal fixture <NUM> provided on the upper part of the opening/closing lid <NUM> is locked onto the locking site 36b, whereby the opening/closing lid <NUM> is retained in the open state. When the supply of electrical power is stopped, and retention (attraction) by the electromagnetic chuck <NUM> is released, the retaining metal fixture <NUM> is rotated about the support shaft <NUM> by the weight of the opening/closing lid <NUM>, whereby the locked metal fixture <NUM> of the opening/closing lid <NUM> is disengaged from the retaining metal fixture <NUM>. As a result, the opening/closing lid <NUM> rotates (falls) about hinges <NUM>, and the opening <NUM> is placed in a closed state (refer to the solid line in <FIG>).

The hinges <NUM> are attached between the opening/closing lid <NUM> and portions of the frame portion <NUM> of the base platform <NUM> where the pedestal <NUM> is provided. Consequently, at first, the opening/closing lid <NUM> is retained by the retention mechanism <NUM> in a state of being oriented obliquely upward with the hinges <NUM> serving as a fulcrum or point of rotation. When the retention by the retention mechanism <NUM> is released, the opening/closing lid <NUM> falls downward due to its own weight, and at this time, the opening/closing lid <NUM> rotates downward about the hinges <NUM>, and closes the opening <NUM>. Moreover, in the example shown in <FIG>, a case is shown in which the hinges <NUM> are attached on both left and right sides of a long side of the opening/closing lid <NUM> that are adjacent to a portion where the pedestal <NUM> of the frame portion <NUM> is provided. Of course, the positions where the hinges <NUM> are attached and the number of the hinges <NUM> may be appropriately set in accordance with the shape of the opening/closing lid <NUM>.

As shown in <FIG>, when the supply of electrical power is restarted, the return mechanism <NUM> lifts the opening/closing lid <NUM> upward, and causes the opening/closing lid <NUM> to be returned to the state of being retained by the retention mechanism <NUM>. Further, during the supply of electrical power, even if the retention by the electromagnetic chuck <NUM> is released and the opening/closing lid <NUM> is placed in the closed state, the opening/closing lid <NUM> is lifted upward, and the opening/closing lid <NUM> is returned to the state of being retained by the retention mechanism <NUM>.

More specifically, as shown in <FIG> and <FIG>, the return mechanism <NUM> includes a motor <NUM>, an arm <NUM> that rotates the opening/closing lid <NUM> upward accompanying rotation of the motor <NUM>, a rotation control unit <NUM> that controls rotational driving of the motor <NUM> (see <FIG>), and a transmission mechanism <NUM> that transmits a rotational force of the motor <NUM> to the arm <NUM> (see <FIG>, <FIG>).

Further, as shown in <FIG>, the return mechanism <NUM> includes a handle <NUM> provided on an upper surface of the opening/closing lid <NUM>, and a hinge pin <NUM> provided on the handle <NUM>. The handle <NUM> is formed by, for example, opposing two L-shaped metal plates 52a and 52b (see <FIG>) that extend from a side on which the hinges <NUM> are attached toward a side opposing to that side. The hinge pin <NUM> is connected between the two metal plates 52a and 52b.

The motor <NUM> is installed on the pedestal <NUM> in a manner so that an output shaft <NUM> (rotary shaft) of the motor <NUM> penetrates through the second metal plate 32B (see <FIG>) of the motor base <NUM>.

As shown in <FIG>, the transmission mechanism <NUM> includes a cam plate <NUM> attached to the output shaft <NUM> of the motor <NUM> that penetrates through the second metal plate 32B. The cam plate <NUM> includes a cam surface 56a formed by an outwardly bulging portion of a disk-shaped peripheral surface thereof.

As shown in <FIG>, the rotation control unit <NUM> includes a damper internal circuit <NUM> connected between a power supply line <NUM> and a ground line <NUM>, and a first switch 66A and a second switch 66B connected respectively between the power supply line <NUM> and the damper internal circuit <NUM>. The first switch 66A includes, for example, a normally open type make contact 68a (a-contact), and is turned on when supply of electrical power from the external power source or the like is started. Consequently, electrical power is supplied to the damper internal circuit <NUM> through the power supply line <NUM>. On the other hand, the second switch 66B includes, for example, a normally closed type break contact 68b (b-contact), and normally, electrical power from the external power source or the like is supplied to the damper internal circuit <NUM> through the power supply line <NUM>.

The damper internal circuit <NUM> includes, for example, four contacts (first through fourth contacts 70a to 70d). The first switch 66A is connected between the power supply line <NUM> and the first contact 70a, and the second switch 66B is connected between the power supply line <NUM> and the second contact 70b. The third contact 70c and the fourth contact 70d are connected to the ground line <NUM>.

Further, the damper internal circuit <NUM> includes the motor <NUM> connected between the first contact 70a and the third contact 70c, a first limit switch 74A and a second limit switch 74B connected in parallel between the first contact 70a and the motor <NUM>, and the electromagnetic chuck <NUM> connected between the second contact 70b and the fourth contact 70d.

The first limit switch 74A includes, for example, a normally closed type first break contact 78a, and the second limit switch 74B includes, for example, a normally closed type second break contact 78b. Accordingly, as can be understood from <FIG>, the motor <NUM> is rotationally driven when at least one of the first break contact 78a and the second break contact 78b is placed in an on state.

Further, as shown in <FIG>, the first limit switch 74A is attached, for example, between the mounting metal fixture <NUM> and the opening/closing lid <NUM>. Preferably, the first limit switch 74A is attached at a position where the first break contact 78a of the first limit switch 74A becomes placed in the off state by the opening/closing lid <NUM>, at a stage when the opening/closing lid <NUM> transitions to the open state. Of course, the first limit switch 74A may be attached at a position where the first break contact 78a thereof becomes placed in the off state, at a stage when the opening/closing lid <NUM> is fully opened.

The second limit switch 74B, for example, is attached to a surface of the second metal plate 32B of the motor base <NUM>, the surface facing the arm <NUM>, above the cam plate <NUM>. Preferably, the second limit switch 74B is attached at a position where the second break contact 78b is placed in the off state by the cam surface 56a of the cam plate <NUM>. In an initial state, specifically, in a state in which the arm <NUM> is in an initial position, as shown in <FIG>, a pin 80a of a crank plate <NUM> is in an upper limit position, and the cam surface 56a of the cam plate <NUM> presses the second break contact 78b of the second limit switch 74B, whereby the second break contact 78b becomes placed in the off state. Moreover, the upper limit position refers to a position from which the pin 80a is incapable of being moved upward any further.

Accordingly, when the cam plate <NUM> is rotated due to rotation of the motor <NUM>, the second break contact 78b becomes placed in the off state over a period of time during which the cam surface 56a presses the second break contact 78b of the second limit switch 74B. When the cam surface 56a separates away from the second break contact 78b, the second break contact 78b is placed in the on state.

As shown in <FIG>, <FIG>, the transmission mechanism <NUM> includes the crank plate <NUM>, which is disposed on an outer side of the cam plate <NUM> and is attached to the output shaft <NUM> of the motor <NUM>. The crank plate <NUM> is provided with, on the surface thereof that is opposite to the cam plate <NUM> side and at an eccentric position, the pin 80a which projects outwardly.

As shown in <FIG> and <FIG>, the arm <NUM> is constituted by an elongate metal fixture having an L-shaped cross section and extending from the base platform <NUM> side toward the opening/closing lid <NUM> side. As shown in <FIG>, the arm <NUM> includes a rotary shaft <NUM> provided in a central portion thereof, and an elongate hole <NUM> which is provided on the base platform <NUM> side, and through which the pin 80a of the crank plate <NUM> is inserted. The elongate hole <NUM> is formed so that a major axis thereof lies along the longitudinal direction of the arm <NUM>.

When the crank plate <NUM> is rotated in one direction (in a counterclockwise direction when viewed from the output shaft <NUM> of the motor <NUM>) by rotational driving of the motor <NUM>, the pin 80a of the crank plate <NUM> slides along the elongate hole <NUM> of the arm <NUM> while rotating. Consequently, the arm <NUM> rotates in a counterclockwise direction about the rotary shaft <NUM>, and the hinge pin <NUM> of the handle <NUM> is hooked on a distal end portion 42a (see <FIG>) on the opening/closing lid <NUM> side, and is lifted upward. As a result, the opening/closing lid <NUM> is rotated upward about the hinges <NUM>, and is retained in the open state by the electromagnetic chuck <NUM>.

In this instance, operations of the damper opening/closing device <NUM> according to the present embodiment will be described with reference to the time chart shown in <FIG>.

First, at time t1, when supply of electrical power to the power supply line <NUM> from the external power source or the like is carried out, the first switch 66A is placed in the on state, and electrical power is supplied to the motor <NUM>, together with electrical power being supplied to the electromagnetic chuck <NUM> via the second switch 66B. For example, as shown in <FIG>, by electrical power being supplied to the motor <NUM> (see <FIG>), the cam plate <NUM> and the crank plate <NUM> are rotated in a counterclockwise direction, and along therewith, the cam surface 56a of the cam plate <NUM> separates away from the second break contact 78b of the second limit switch 74B, and the second limit switch 74B becomes placed in the on state (at time t2). Further, the arm <NUM> is also rotated in a counterclockwise direction about the rotary shaft <NUM>, and gradually lifts the opening/closing lid <NUM> upward (refer to the two-dot-dashed line in <FIG>). Consequently, the opening/closing lid <NUM> rotates upward about the hinges <NUM>.

In addition, accompanying rotation of the cam plate <NUM> and the crank plate <NUM>, the pin 80a of the crank plate <NUM> arrives, for example, at a lower limit position, or alternatively in the vicinity thereof, and at a stage (for example, at time t3) at which the opening/closing lid <NUM> is fully opened, the opening/closing lid <NUM> is retained by the electromagnetic chuck <NUM>. Moreover, the lower limit position refers to a position from which the pin 80a is incapable of being moved downward any further. Further, at this time, in accordance with the first break contact 78a being pressed by the opening/closing lid <NUM>, the first limit switch 74A becomes placed in the off state. At this stage, since electrical power is being supplied to the motor <NUM> via the second limit switch 74B, the cam plate <NUM> and the crank plate <NUM> continue to rotate in the counterclockwise direction.

Thereafter, accompanying rotation of the cam plate <NUM> and the crank plate <NUM>, the cam surface 56a of the cam plate <NUM> presses the second break contact 78b of the second limit switch 74B, whereby the second break contact 78b becomes placed in the off state (at time t4), and supply of electrical power to the motor <NUM> is stopped. At this time, since the pin 80a arrives at the upper limit position, or alternatively in the vicinity thereof and the cam plate <NUM> and the crank plate <NUM> stop rotating, the arm <NUM> is returned to the initial state (refer to the solid line in <FIG>).

If the retention of the opening/closing lid <NUM> by the electromagnetic chuck <NUM> is released and the opening/closing lid <NUM> becomes placed in the closed state due to its own weight, since the first break contact 78a of the first limit switch 74A is placed in the on state (at time t5), rotational driving of the motor <NUM> is started (restarted) again, the operations at the times t2 to t4 are repeated, and the opening/closing lid <NUM> is returned to the open state. Such a returning operation is based on priority being given to driving of the opening/closing lid <NUM> to be opened, because basically, it is necessary for the opening/closing lid <NUM> to be maintained open (in a state of supplying air) at all times.

In contrast thereto, at the time of an emergency (at a time when a combustible gas is detected or the like), the opening/closing lid <NUM> is placed in the closed state by stopping the supply of electrical power to the power supply line <NUM>. More specifically, for example, at time t6, in the case that a combustible gas is detected, the supply of electrical power to the power supply line <NUM> from the external power source or the like is stopped. Consequently, the supply of electrical power to the electromagnetic chuck <NUM> and the motor <NUM> is stopped, and the opening/closing lid <NUM> becomes placed in the closed state.

In this manner, in the damper opening/closing device <NUM> according to the present embodiment, the opening/closing lid <NUM> is retained by the retention mechanism <NUM> in a state of being oriented obliquely upward with the hinges <NUM> serving as a fulcrum or point of rotation, whereby the opening <NUM> can be placed in the open state. Even if the retention by the electromagnetic chuck <NUM> is released and the opening/closing lid <NUM> is placed in the closed state, the opening/closing lid <NUM> is driven by the return mechanism <NUM>, and the opening/closing lid <NUM> can be returned to the state of being retained by the retention mechanism <NUM>. In particular, when the opening/closing lid <NUM> is retained in the open state by the retention mechanism <NUM>, the arm <NUM> is returned to the initial position. Therefore, the opening/closing lid <NUM> can be smoothly returned to the open state by the return mechanism <NUM>.

On the other hand, at the time of an emergency or the like, when the supply of electrical power to the retention mechanism <NUM> is stopped, the retention by the retention mechanism <NUM> is released, and the opening/closing lid <NUM> falls downward due to its own weight. At this time, the opening/closing lid <NUM> rotates downward about the hinges <NUM>, and closes the opening <NUM>. More specifically, the opening <NUM> can be placed in the closed state. Even if the supply of electrical power from the external power source is cut off, the opening <NUM> can be closed without using an electrical means such as an electrical power storage means or the like, and consumption of electrical power (standby power or the like) can be reduced.

In the case that the supply of electrical power from the external power source is restarted, the opening/closing lid <NUM> is retained again by the retention mechanism <NUM> in a state of being oriented obliquely upward with the hinges <NUM> serving as a fulcrum or point of rotation, whereby the opening <NUM> can be placed in the open state.

Further, according to the present embodiment, there are included the crank plate <NUM> which is rotated by driving of the motor <NUM>, and rotates the arm <NUM> in a direction to open the opening/closing lid <NUM>, and the cam plate <NUM> which is rotated together with the crank plate <NUM> by driving of the motor <NUM>. The cam plate <NUM> includes the cam surface 56a that places the second break contact 78b in an off state based on the arm <NUM> being returned to the initial position.

By rotating the crank plate <NUM> together with the cam plate <NUM> by the motor <NUM>, it is possible to perform, by the single motor <NUM>, the operation of rotating the arm <NUM> in the direction to open the opening/closing lid <NUM> by the crank plate <NUM>, and the operation of placing the second break contact 78b in the off state by the cam surface 56a of the cam plate <NUM> based on the arm <NUM> being returned to its initial position, and it is possible to effectively simplify the structure and reduce the number of component parts.

The above-described embodiment can be summarized in the following manner.

The damper opening/closing device <NUM> is a damper opening/closing device installed in the opening <NUM> used for air conditioning, and comprises the opening/closing lid <NUM>, the retention mechanism <NUM> that retains the opening/closing lid <NUM> and places the opening <NUM> in the open state during a period in which supply of electrical power is being carried out, and releases retention of the opening/closing lid <NUM> and places the opening <NUM> in a closed state when the supply of electrical power is stopped, and the return mechanism <NUM> that returns the opening/closing lid <NUM> to the state of being retained by the retention mechanism <NUM>, in the case that the opening/closing lid <NUM> is in the closed state during the period in which supply of electrical power is being carried out.

In accordance with these features, initially, during the period in which electrical power is being supplied, the retention mechanism <NUM> retains the opening/closing lid <NUM> and places the opening <NUM> in the open state. When the supply of electrical power is stopped, the retention mechanism <NUM> releases the retention of the opening/closing lid <NUM>, and thereby places the opening <NUM> in the closed state. In this manner, even if the supply of electrical power from the external power source is cut off, the opening <NUM> can be closed without using an electrical means such as an electrical power storage means or the like, and consumption of electrical power (standby power or the like) can be reduced. Additionally, even if the retention by the retention mechanism <NUM> is released and the opening/closing lid <NUM> is placed in the closed state during the period in which supply of electrical power is being carried out, it is possible for the opening/closing lid <NUM> to be returned to the state of being retained by the retention mechanism <NUM>, by the return mechanism <NUM>.

In the present embodiment, the retention mechanism <NUM> may be the electromagnetic chuck <NUM> that electromagnetically retains the opening/closing lid <NUM>. The opening/closing lid <NUM> can be retained in the open state by supplying electrical power thereto.

In the present embodiment, movement of the opening/closing lid <NUM> when retention of the opening/closing lid <NUM> by the retention mechanism <NUM> is released takes place due to the weight of the opening/closing lid <NUM>. In accordance with this feature, even if the supply of electrical power from the external power source is cut off, the air supply port or the like can be closed by the opening/closing lid <NUM> without using an electrical power storage means or the like.

In the present embodiment, the return mechanism <NUM> includes the first break contact 78a and the second break 78b, the motor <NUM> which is rotationally driven based on at least one of the first break contact 78a and the second break contact 78b being placed in an on state, and the arm <NUM> that rotates in a direction to open the opening/closing lid <NUM> from the initial position as the motor <NUM> is rotationally driven. The first break contact 78a is placed in the off state based on the open state of the opening/closing lid <NUM>, and the second break contact 78b is placed in the off state based on the arm <NUM> being returned to the initial position. In accordance with these features, when the opening/closing lid <NUM> is retained in the open state by the retention mechanism <NUM>, the arm <NUM> is returned to the initial position. Therefore, the opening/closing lid <NUM> can be smoothly returned to the open state by the return mechanism <NUM>.

In the present embodiment, the open state of the opening/closing lid <NUM> is a state in which the opening/closing lid <NUM> is retained by the retention mechanism <NUM>, and the second break contact 78b is placed in the off state based on the arm <NUM> being returned to the initial position, after the first break contact 78a has been placed in the off state.

In the present embodiment, there are further included the crank plate <NUM> which is rotated by driving of the motor <NUM>, and rotates the arm <NUM> in the direction to open the opening/closing lid <NUM>, and the cam plate <NUM> that is rotated together with the crank plate <NUM> by driving of the motor <NUM>, and the cam plate <NUM> includes the cam surface 56a that places the second break contact 78b in the off state based on the arm <NUM> being returned to the initial position.

The crank plate <NUM> and the cam plate <NUM> are rotated together by the motor <NUM>. Consequently, it is possible to perform, by a single motor, the operation of rotating the arm <NUM> in the direction to open the opening/closing lid <NUM> by the crank plate <NUM>, and the operation of placing the second break contact 78b in the off state by the cam surface 56a of the cam plate <NUM> based on the arm <NUM> being returned to its initial position, and it is possible to effectively simplify the structure and reduce the number of component parts.

Claim 1:
A damper opening/closing device (<NUM>) installed in an opening (<NUM>) used for air conditioning, the damper opening/closing device (<NUM>) comprising:
an opening/closing lid (<NUM>);
a retention mechanism (<NUM>) configured to retain the opening/closing lid (<NUM>) and place the opening (<NUM>) in an open state during a period in which supply of electrical power is being carried out, and to release retention of the opening/closing lid (<NUM>) and place the opening (<NUM>) in a closed state when the supply of electrical power is stopped; and
a return mechanism (<NUM>) configured to return the opening/closing lid (<NUM>) to the state of being retained by the retention mechanism (<NUM>), in a case that the opening/closing lid (<NUM>) is in a closed state during the period in which the supply of electrical power is being carried out;
characterized in that
the return mechanism (<NUM>) includes:
a first break contact (78a) and a second break contact (78b);
a motor (<NUM>) configured to be rotationally driven based on at least one of the first break contact (78a) and the second break contact (78b) being placed in an on state; and
an arm (<NUM>) configured to rotate in a direction to open the opening/closing lid (<NUM>) from an initial position as the motor (<NUM>) is rotationally driven,
the first break contact (78a) is placed in an off state based on an open state of the opening/closing lid (<NUM>), and
the second break contact (78b) is placed in an off state based on the arm (<NUM>) being returned to the initial position; and
a crank plate (<NUM>) configured to be rotated by driving of the motor (<NUM>), and to rotate the arm (<NUM>) in the direction to open the opening/closing lid (<NUM>); and
a cam plate (<NUM>) configured to be rotated together with the crank plate (<NUM>) by driving of the motor (<NUM>), wherein
the cam plate (<NUM>) includes a cam surface (56a) configured to place the second break contact (78b) in the off state based on the arm (<NUM>) being returned to the initial position.