Elevator for construction work

Abstract

To make it a task to bring a carriage to safely a stop when voltage drops in an elevator for construction works.SOLUTION: It is characterized that an elevator for construction works 100 capable of stopping at electric power dropping comprises an inverter 30 to supply an electric power source to a carriage driving unit 40 owned by the carriage 10, a voltage monitoring part 20 to monitor the supply voltage drop to the inverter, a power shut-off part 50 to cut off the power source supply to the inverter when the voltage monitoring part detects that the supply voltage to the inverter is not more than the predetermined threshold, and a carriage stopping part 60 to stop the carriage from ascending / descending when the power shut-off part cuts off the power source supply to the inverter.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention is directed to a construction elevator used at a construction site, which prevents a drop in power supply voltage and a decrease in torque of a motor for raising and lowering a carriage, thereby safely stopping the carriage in the event of a voltage drop. [Background technology]

[0002] In construction elevators used on construction sites, a stable power supply voltage is normally supplied to the carriage lifting motor mounted on the carriage from an inverter placed outside the carriage. However, voltage drops are likely to occur, especially when the carriage is rising, and although the inverter tries to maintain the voltage supplied to the carriage lifting motor, the torque is insufficient, affecting the carriage's lifting and lowering, and in the worst case scenario, the carriage may fall to the ground.

[0003] Patent Document 1 describes a method for detecting a voltage drop, cutting off the inverter, and bringing the door to an emergency stop. [Prior art documents] [Patent documents]

[0004] Patent document 1: Japanese Patent Application Laid-Open No. 4-133989 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 relates to the opening and closing of doors, and makes no mention of matters related to the raising and lowering of the carriage due to a voltage drop. As a result, even if a voltage drop was detected, the carriage could not be stopped safely.

[0006] The present invention aims to solve the above problems and to safely stop a carriage in a construction elevator when a voltage drop occurs. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a construction elevator that can be stopped when the power supply drops, An inverter that supplies power to a carriage drive unit provided in the carriage; a voltage monitoring unit that monitors a drop in a voltage supplied to the inverter; a power cutoff unit that cuts off power supply to the inverter when the voltage monitoring unit detects that a voltage supplied to the inverter falls below a predetermined threshold; The present invention provides a construction elevator, characterized in that it is equipped with a carriage lifting / lowering stop unit that stops the lifting and lowering of the carriage when the power supply cut-off unit cuts off the power supply to the inverter.

[0008] With this configuration, in a construction elevator, the carriage can be stopped safely even if the voltage supplied to the inverter drops.

[0009] In a construction elevator, the carriage drive unit may include a motor, and the carriage lifting / lowering stopping unit may be configured as a brake provided on the motor.

[0010] This configuration allows the carrier to be stopped safely with a compact configuration.

[0011] The construction elevator may be configured such that the voltage monitoring unit monitors a drop in the voltage supplied to the inverter when the carriage is ascending or descending.

[0012] With this configuration, by limiting voltage monitoring to when the torque is insufficient during ascent or descent, voltage drops can be detected efficiently and the effects of malfunctions can be minimized. Effect of the Invention

[0013] The construction elevator of the present invention allows the carriage to be stopped safely in the event of a voltage drop. [Brief description of the drawings]

[0014] [Figure 1]FIG. 1 is a schematic diagram illustrating a construction elevator in a first embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram for explaining a control circuit for dealing with a voltage drop in a construction elevator in the first embodiment of the present invention. [Diagram 3] FIG. 11 is a diagram for explaining a control circuit for dealing with a voltage drop in a construction elevator in a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLES

[0015] A first embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram illustrating an elevator for construction work in the first embodiment of the present invention. Figure 2 is a diagram illustrating a control circuit for dealing with a voltage drop in the elevator for construction work in the first embodiment of the present invention.

[0016] In the construction elevator 100 in the first embodiment, a carriage 10 on which people and cargo board and disembark is raised and lowered along a hoistway 11 by a carriage drive unit 40. The carriage drive unit 40 is provided at the bottom of the carriage 10, and power is supplied from an inverter 30 installed on the ground via a cable 12. In addition, a voltage monitoring unit 20 that monitors a drop in the supply voltage to the inverter 30 is installed on the ground, and a power supply cut-off unit 50 that cuts off the power supply to the inverter 30 when the voltage monitoring unit 20 detects that the supply voltage to the inverter 30 has fallen below a predetermined threshold (i.e., the voltage has dropped) is provided in the voltage monitoring unit 20. When the power supply cut-off unit 50 cuts off the power supply to the inverter 30, a carriage lifting stop unit 60 that stops the lifting and lowering of the carriage 10 is provided at the bottom of the carriage 10.

[0017] The carriage 10 moves up and down on a rack provided in the elevator 11 by a carriage drive unit 40 provided at the bottom of the carriage 10 driving a pinion. The carriage drive unit 40 has two motors, a first motor 41 and a second motor 42, and these two motors each drive a different pinion. In addition, the two motors are connected in parallel to the outputs of the inverter 30.

[0018] The inverter 30 converts the supplied AC voltage to DC once, and then converts it back to AC and outputs it. In the first embodiment, the supply voltage is 440V at 50 / 60Hz, and the output voltage is also 440V. However, this is not necessarily limited to this and can be changed as appropriate. For example, the output voltage may be 400V or 480V. The supply voltage may also be changed to a voltage value other than 440V.

[0019] In the first embodiment, the carriage drive unit 40 is provided at the bottom of the carriage 10, but this is not necessarily limited to this and can be modified as appropriate. For example, the carriage drive unit 40 may be provided at the top of the carriage 10.

[0020] In addition, although the carriage drive unit 40 has two motors, this is not necessarily limited to this and can be modified as appropriate. For example, it may have one motor, or three or more motors. This can be determined based on the weight of the carriage 10, etc.

[0021] The voltage monitoring unit 20 has a voltage drop detection unit 21 that detects a drop in the three-phase power supply voltage supplied to the inverter 30. The voltage drop detection unit 21 includes a voltage detection relay (manufactured by Omron) and is normally turned on. The voltage drop detection unit 21 is configured to turn off an internal relay contact when the voltage input to the inverter 30 falls below a predetermined threshold. This predetermined threshold can be set in advance by a volume provided in the voltage detection relay, and is set to 380V in the first embodiment.

[0022] One relay contact PW1 of the voltage drop detection unit 21 is connected to the power source S, and the other relay contact R2 is connected to the MS relay 51a and MSY relay 52a in the power supply cutoff unit 50, and then connected to the power source R. As a result, when the relay contact of the voltage drop detection unit 21 is turned off, the MS relay 51a and the MSY relay 52a are no longer driven, and the MS relay contact 51b in the power supply cutoff unit 50 is opened (turned off), cutting off the voltage supplied to the inverter 30. At the same time, the MSY relay contact 52b is turned off, opening the c-terminals and b-terminals of the inverter 30, and notifying the inverter of an inverter abnormality.

[0023] When the inverter 30 is notified of an inverter abnormality, it instructs the carrier lifting / lowering stop unit 60 provided in the carrier 10 to make an emergency stop of the lifting / lowering of the carrier 10. Specifically, the driving of the first motor 41 and the second motor 42 is stopped, and the first brake 61 and the second brake in the carrier lifting / lowering stop unit 60 are driven to make an emergency stop by friction, thereby bringing the carrier 10 to an emergency stop.

[0024] Here, in reality, the first brake 61 is built into the first motor 41, and the second brake 62 is built into the second motor 42. Normally, the first brake 61 and the second brake 62 are released, but an emergency stop command from the inverter 30 drives an electromagnetic coil (not shown) to stop each motor by friction.

[0025] In the first embodiment, the voltage drop detector 21 is configured with a voltage detection relay (manufactured by Omron), but this is not necessarily limited to this and can be modified as appropriate. For example, it may be configured with any electronic circuit. In the first embodiment, the threshold for detecting the voltage drop is variable, but this is not necessarily limited to this and can be modified as appropriate. For example, the threshold for detecting the voltage drop may be fixed to make the configuration more compact.

[0026] Thus, in the first embodiment, the elevator for construction work can be stopped when the power supply drops, An inverter that supplies power to a carriage drive unit provided in the carriage; a voltage monitoring unit that monitors a drop in a voltage supplied to the inverter; a power cutoff unit that cuts off power supply to the inverter when the voltage monitoring unit detects that a voltage supplied to the inverter falls below a predetermined threshold; A construction elevator that is characterized by being equipped with a carriage lifting stop unit that stops the lifting and lowering of the carriage when the power supply cut-off unit cuts off the power supply to the inverter, allows the carriage to be stopped safely even if the input voltage to the inverter drops. EXAMPLES

[0027] The second embodiment of the present invention differs from the first embodiment in that a drop in the voltage supplied to the inverter is monitored only when the carriage is ascending or descending. The second embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram for explaining a control circuit for dealing with a voltage drop in a construction elevator in the second embodiment of the present invention.

[0028] In the construction elevator 200 in the second embodiment, a carriage 10 on which people and cargo board and disembark is raised and lowered along a hoistway 11 by a carriage drive unit 40. The carriage drive unit 40 is provided at the bottom of the carriage 10, and power is supplied from an inverter 30 installed on the ground via a cable 12. In addition, a voltage monitoring unit 20 that monitors a drop in the supply voltage to the inverter 30 is provided on the ground, and a power supply cutoff unit 50 is provided that cuts off the power supply to the inverter 30 when the voltage monitoring unit 120 detects that the supply voltage to the inverter 30 has fallen below a predetermined threshold (i.e., the voltage has dropped). When the power supply cutoff unit 50 cuts off the power supply to the inverter 30, a carriage lifting stop unit 60 that stops the lifting and lowering of the carriage 10 is provided at the bottom of the carriage 10.

[0029] The carriage 10 moves up and down on a rack provided in the elevator 11 by a carriage drive unit 40 provided at the bottom of the carriage 10 driving a pinion. The carriage drive unit 40 has two motors, a first motor 41 and a second motor 42, and these two motors each drive a different pinion. In addition, the two motors are connected in parallel to the outputs of the inverter 30.

[0030] The construction elevator 200 of the second embodiment includes a voltage monitoring unit 120. As in the first embodiment, the voltage monitoring unit 120 includes a voltage drop detection unit 21 that detects a drop in the three-phase power supply voltage supplied to the inverter 30. The voltage drop detection unit 21 is configured such that a relay contact is normally on, but the internal relay contact is turned off when the voltage input to the inverter 30 falls below a predetermined threshold value.

[0031] In the second embodiment, one contact terminal PW1 of the relay contact of the voltage drop detection unit 21 is connected to one terminal of the UTY relay contact 124. The other terminal of the UTY relay contact 124 is connected to a circuit (not shown) and then to a power source S, and one contact terminal R2 of the relay contact of the voltage drop detection unit 21 is connected to the MS relay 51a and the MSY relay 52a and then to a power source R.

[0032] The UTY relay contact 124 is normally open (OFF) and is turned on by a circuit not shown when the carrier 10 ascends. In other words, when the carrier 10 ascends, one contact terminal PW1 of the relay contact of the voltage drop detection unit 21 is connected to the power source S.

[0033] In the first embodiment, the UTY relay contact 124 is turned on only when the carriage 10 ascends, but this is not necessarily limited to this and can be modified as appropriate. For example, the UTY relay contact 124 may be turned on only when the carriage 10 descends, or the UTY relay contact 124 may be turned on when the carriage 10 ascends and descends.

[0034] As a result, when the carrier 10 rises or falls, the relay contact of the voltage drop detection unit 21 turns off, the MS relay 51a and the MSY relay 52a are no longer driven, and the MS relay contact 51b in the power supply cutoff unit 50 is opened (off) to cut off the input power to the inverter 30. At the same time, the MSY relay contact 52b turns off, the c terminals and b terminals of the inverter 30 are opened, and the inverter 30 is notified that an inverter abnormality has occurred.

[0035] Then, when the inverter abnormality is notified to the inverter 30, an instruction is given to the carrier lifting / lowering stop unit 60 provided in the carrier 10 to make an emergency stop of the lifting / lowering of the carrier 10. Specifically, the first brake 61 and the second brake in the carrier lifting / lowering stop unit 60 are driven to stop the first motor 41 and the second motor 42 in the carrier drive unit 40 by friction, thereby making an emergency stop of the carrier 10.

[0036] In this way, in Example 2, the voltage monitoring unit monitors the drop in the voltage supplied to the inverter when the carrier rises or falls, and by monitoring the voltage during rise or fall when there is a risk of torque insufficiency, the voltage drop can be detected efficiently and the effects of malfunction can be minimized. [Industrial Applicability]

[0037] The construction elevator of the present invention can be applied to all construction elevators that prevent a drop in power supply voltage and a decrease in torque to the motor for raising and lowering the carriage, and safely stop the carriage in the event of a voltage drop. [Explanation of symbols]

[0038] 10:Carrier 11: Lift 12: Cable 20: Voltage monitoring unit 21: Voltage drop detection unit 30: Inverter 40: Carriage drive unit 41: First motor 42: Second motor 50: Power cutoff section 51a: MS Relay 51b: MS relay contact 52a:MSY Relay 52b: MSY relay contact 60: Carriage lift stop 61: First brake 62: Second brake 100: Construction elevator 120: Voltage monitoring unit 124: UTY relay contact 200: Construction elevator W: Wall G: Ground

Claims

1. A construction elevator that can be stopped when the power supply drops, An inverter that supplies power to a carriage drive unit provided in the carriage; a voltage monitoring unit that monitors a drop in a voltage supplied to the inverter; a power cutoff unit that cuts off power supply to the inverter when the voltage monitoring unit detects that a voltage supplied to the inverter falls below a predetermined threshold; A construction elevator comprising: a carriage lifting / lowering stop unit that stops the lifting / lowering of the carriage when the power supply cut-off unit cuts off the power supply to the inverter.

2. 2. The construction elevator according to claim 1, wherein the carriage drive unit includes a motor, and the carriage lifting / lowering stopping unit is a brake provided on the motor.

3. 3. The construction elevator according to claim 1, wherein the voltage monitoring unit monitors a drop in the voltage supplied to the inverter when the carriage is ascending or descending.

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