JP4090126B2 - Pull cord switch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pull cord switch in which a plurality of switches are inserted in a long wire, and more particularly to a pull cord switch that can quickly find an abnormality occurrence location.
[0002]
[Prior art]
For example, a conveyor for carrying earth and sand and ore has a length of several hundred meters or 1 km or more. In such a long machine facility, a pull cord switch is used to make an emergency stop in the event of an abnormality. As shown in FIG. 4, the pull cord switch has a wire 4 in which a normally closed switch (hereinafter referred to as an individual switch) 1 whose contact (not shown) is normally closed is stretched between the individual switches 1. The wire 4 is hooked to the contact opening / closing mechanism (see FIG. 5) of each individual switch 1, and the one end of the wire 4 detects that the wire 4 has been pulled. The relay 5a held by the current flowing through the wire 4 is provided. The wires 4 are stretched so as to surround the mechanical equipment 41, and the individual switches 1 are provided at intervals of 50 m, for example.
[0003]
As shown in FIG. 5, the individual switch has a rod-shaped contact opening / closing mechanism 52 that is rotated around a fulcrum 51, and a contact (not shown) is opened / closed by rotating the contact opening / closing mechanism 52. It has become. As shown in FIG. 5 (a), the individual switch closes the contact when the contact opening / closing mechanism 52 has a large angle with respect to the direction in which the wire 4 is stretched, and as shown in FIG. The opening / closing mechanism 52 is provided so as to open the contact when it falls in the direction in which the wire 4 is stretched.
[0004]
A voltage E which is a rated operating voltage of the relay 5a is applied to both ends of the wire 4. The applied voltage E is, for example, a direct current, but may be an alternating current.
[0005]
In the above-described pull cord switch, the voltage E is applied to both ends of the wire 4, and when normal, all the contacts of the individual switches 1 are closed. Therefore, the voltage E is applied to the operating coil of the relay 5a. Is done. That is, the relay 5a is held. Therefore, the contact of the relay 5a may be connected to an alarm device, and the alarm device may be configured so that the alarm is off (normal) logic when the relay 5a is held. When stopping by inspection and repair of the mechanical equipment 41, or in case of emergency stop when an abnormality occurs, when the wire 4 is pulled, the contact opening / closing mechanism 52 is rotated in the nearest individual switch 1, and the contact of the individual switch 1 is thereby moved. be opened. The voltage is no longer applied to the operating coil of the relay 5a, and the relay 5a is cut off. For this reason, in the alarm device, the logic of alarm ON (abnormality) is detected, the mechanical equipment 41 is emergency stopped, and an alarm is issued to the supervisor.
[0006]
[Problems to be solved by the invention]
By the way, in the said pull cord switch, since all the individual switches 1 are connected in series, when the contact of any one individual switch 1 is opened, the detection element 5 operates and an abnormality is detected by the alarm device. However, it is unknown from the alarm device in which individual switch 1 the abnormality occurred. Therefore, in the prior art, a flag is added to each individual switch 1. As shown in FIG. 5, the flag 53 has a structure in which a flat plate is provided at the tip of the rod, and is attached to the individual switch 1 so as to rotate in conjunction with the contact opening / closing mechanism 52. The flag 53 is turned upside down so that the flat plate is not conspicuous under normal conditions. When the wire 4 is pulled, the flag 53 is raised with the rotation of the contact opening / closing mechanism 52 and the flat plate appears at a conspicuous position. Accordingly, the monitoring person who receives the warning and confirms the site can find the location where the abnormality has occurred by visually checking the flag 53.
[0007]
However, since the individual switches 1 are provided at a wide interval of, for example, 50 m, it is difficult for the monitor to determine whether or not the flag 53 having a size of about 20 cm is present, and the contact point is not visible. It is difficult to determine how far the individual switch 1 is in an operating state after standing up. For this reason, a quick on-site confirmation cannot be performed, and the operation efficiency of the conveyor is unnecessarily lowered.
[0008]
Further, in the pull cord switch, since the wire 4 is elongated, the sensitivity may change due to the expansion and contraction of the wire 4 due to a temperature difference, and inspection and adjustment are necessary. For example, since the operation cannot be started if the individual switch 1 remains in the activated state at the start of the operation of the mechanical equipment, it is necessary for the supervisor to check and return the activated individual switch 1 to the non-activated state. However, at this time, it is difficult to determine whether the individual switch 1 is in the operating state or the non-operating state from the standing angle of the flag 53. For the same reason, it is difficult to understand the result when adjusting the extent to which an abnormality is detected when the wire 4 is pulled on site.
[0009]
Accordingly, an object of the present invention is to provide a pull cord switch that solves the above-mentioned problems and can quickly find an abnormality occurrence location.
[0010]
[Means for Solving the Problems]
To accomplish the above object, Ru hooked the wire into the contact opening and closing mechanism of the individual switches with a plurality of individual switches which contact is closed to connect in series by a tension passing wires between these individual switches Accordingly, in the pull cord switch configured to open the contact of the individual switch when the contact opening / closing mechanism falls in the wire extending direction, the detection element for detecting that the wire is pulled It consists of a relay in which an operation coil is connected in series to a wire, and an indicator lamp that lights when the contact is opened is connected in parallel to the contact of each individual switch, and flows to the wire when the contact is closed the relay current is maintained, the current flowing through the wire when the indicator the contact is opened is lit the holding current of the relay In which said wire is cut off the relay is pulled has to be detected by the turn.
[0011]
The indicator lamp may be composed of a light emitting diode.
[0012]
An additional resistor may be provided in series with the indicator lamp so that the current flowing through the wire when the indicator lamp is turned on is less than the holding current of the relay .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
[0014]
As shown in FIG. 1, in the pull cord switch of the present invention, an indicator lamp 3 that is turned on when the contact 2 is opened is connected in parallel to the contact 2 of each individual switch 1, and the indicator lamp 3 is lit. In some cases, the relay 5a, which is the detection element 5, is activated by the current flowing through the wire 4. Here, the indicator lamp 3 is a light-emitting diode lamp composed of a light-emitting diode such as a high-intensity LED, and 6 is an additional resistor for current limitation inserted in series with the light-emitting diode. That is, when the contact 2 of the individual switch 1 is opened, the pull cord switch of FIG. 1 has a rated current for turning on the light-emitting diode of the indicator lamp 3 or a current lower than that, and lower than the holding current of the operating coil of the relay 5a. In this configuration, a current flows through the wire 4. The pull cord switch is installed as shown in FIG. 4 as in the prior art.
[0015]
A voltage E that is a rated operating voltage of the relay is applied to both ends of the wire 4. Here, the applied voltage E is a direct current, but may be an alternating current.
[0016]
In the above-described pull cord switch, the voltage E is applied to both ends of the wire 4, and since the contacts 2 of the individual switches 1 are all closed during normal operation, the voltage E is applied to the operating coil of the relay 5a. Applied. That is, the relay 5a is held. Therefore, the contact (not shown) of the relay 5a may be connected to an alarm device (not shown), and the alarm device may be configured so that the alarm is turned off when the relay 5a is held. At this time, since no voltage is applied to the indicator lamps 3 corresponding to the individual switches 1, none of the indicator lamps 3 is lit. When stopping at the time of inspection and repair of mechanical equipment or when an emergency stop occurs when an abnormality occurs, when the wire 4 is pulled, the contact opening / closing mechanism 52 is rotated in the nearest individual switch 1, whereby the contact 2 of the individual switch 1 is moved. be opened. A voltage is applied to the indicator lamp 3 corresponding to the individual switch 1, and a current flows through the indicator lamp 3 via the wire 4. The current flowing through the wire 4 is determined by the series resistance of the additional resistor 6 and the internal resistance of the operating coil of the relay 5a. This current is a current that causes the light emitting diode of the indicator lamp 3 to emit light with sufficient brightness and is not excessive for the light emitting diode. Further, this current is less than the holding current of the operating coil of the relay 5a. Therefore, the relay 5a is cut off. For this reason, the alarm device detects the alarm-on logic, the machine is emergency stopped, and an alarm is issued to the supervisor.
[0017]
The supervisor who goes to the site confirmation after receiving the alarm only needs to find the indicator lamp 3 that is lit, so it can be found more easily than the conventional flag. Therefore, the location where an abnormality has occurred can be found quickly. Also during the inspection and adjustment, it can be immediately judged by the indicator lamp 3 whether the individual switch 1 is in the activated state or inoperative state.
[0018]
The indicator lamp 3 includes an incandescent lamp, a light-emitting diode lamp, and the like. In the embodiment of FIG. 1 using the relay 5a as the detection element 5, the operation stability is good when the light-emitting diode lamp is used. The light-emitting diode lamp may be composed of a single light-emitting diode or may be composed of an array in which a plurality of light-emitting diodes are assembled.
[0019]
As shown in FIG. 2, by connecting a plurality of light emitting diodes 21 in series, the total amount of emitted light can be increased and the forward voltage drop can be increased at the same time. As the amount of emitted light increases, visual recognition becomes easier even in a bright environment or from a long distance. Further, as the forward voltage drop increases, the current limiting resistance can be reduced. If there is a sufficient forward voltage drop, the additional resistor 6 can be eliminated and the current can be limited only by the internal resistance of the operating coil of the relay 5a. is there.
[0020]
The detection element 5 is not limited to the electromagnetic relay 5a, and a switching element such as a semiconductor relay or a logic gate can be used.
[0021]
As in the prior art shown in FIG. 5, the individual switch 1 has a contact opening / closing mechanism 52 that rotates around a fulcrum 51, and the contact opening / closing mechanism 52 rotates to open and close a contact (not shown). It has become so. However, the indicator lamp 3 does not need to be mechanically integrated with the individual switch 1 like a flag. Therefore, as shown in FIG. 3, the indicator lamp 3 may be installed at an easily viewable position in the vicinity of the individual switch 1 and electrically connected to the contact of the individual switch 1 via the lead wire 31. The indicator lamp 3 shown in FIG. 3 is an array in which a plurality of light emitting diodes are arranged on a plane or a three-dimensional surface.
[0022]
【The invention's effect】
The present invention exhibits the following excellent effects.
[0023]
(1) Since the indicator lamp is turned on when the contact of the individual switch is opened, the visual recognition becomes easier as compared with the conventional flag.
[0024]
(2) When a conventional pull cord switch is already installed, it can be easily implemented only by adding an indicator lamp.
[0025]
(3) Since the individual switch does not need to support the flag, the individual switch can be expected to be smaller and lighter.
[0026]
(4) Since the indicator lamp only needs to be electrically connected to the individual switch, the indicator lamp can be placed at any easily viewable position.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a pull cord switch showing an embodiment of the present invention.
FIG. 2 is a circuit diagram of an individual switch showing an embodiment of the present invention.
FIG. 3 is an external view of an indicator lamp showing an embodiment of the present invention.
FIG. 4 is a plan view showing an installation state of the pull cord switch.
FIG. 5 is a structural diagram of a conventional individual switch.
[Explanation of symbols]
1 Individual switch 2 Contact 3 Indicator light 4 Wire 5 Detection element

Claims (3)

The Rukoto hooked the wire into the contact opening and closing mechanism of the individual switches with a plurality of individual switches the contacts are closed connected in series by the transfer wire stretched between these individual switches, said contact opening and closing mechanism of the wire In the pull cord switch configured to open the contact of the individual switch when it falls in the spanning direction ,
A detection element for detecting that the wire has been pulled is configured by a relay in which an operation coil is connected in series to the wire, and an indicator lamp that is lit when the contact is opened at each individual switch contact By connecting in parallel, the relay is held by the current flowing through the wire when the contact is closed, and the current flowing through the wire when the contact is open and the indicator lamp is lit is below the holding current of the relay A pull cord switch characterized in that it is detected that the relay is cut off and the wire is pulled .   2. The pull cord switch according to claim 1, wherein the indicator lamp comprises a light emitting diode. 3. The pull cord switch according to claim 1 , wherein an additional resistor is provided in series with the indicator lamp so that a current flowing through the wire is less than a holding current of the relay when the indicator lamp is turned on .

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