JPH06119570A - Alarm system for working machine - Google Patents

Abstract

PURPOSE:To surely monitor a worker or the like and to generate a proper alarm corresponding to a distance by monitoring an object existing within a near distance which is dead space of microwave monitoring by means of ultrasonic waves to be detected at a wide angle. CONSTITUTION:Antennas 2a, 2b are fixed to both the ends of the rear face of a hydraulic shovel 1 e.g. and although microwaves from the antennas 2a, 2b are generated backwards at comparatively wide directional angles, the expanding angle is only about 90 deg.. Thereby an ultrasonic sensor 3 is fixed to the center of the dead space of microwaves from the antennas 2a, 2b. An ultrasonic wave is generated to the backward of the shovel 1 at about 180 deg. directional angle, so that an obstacle or the like is detected over the whole backward directions. Consequently almost all areas near the rear face of the shovel 1 can be detected by an ultrasonic wave transmitter/receiver through the sensor 3 as a detecting range 3a and the dead space of the microwave monitoring can be covered. In addition, the maximum detecting distance of an ultrasonic wave can be comparatively shortened correspondingly to the dead space of the microwave monitoring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alarm system used for a working machine such as a civil engineering and construction machine having an upper swing body such as a hydraulic excavator and a crane. The present invention relates to an alarm system capable of eliminating a blind spot even for an approaching object.

[0002]

2. Description of the Related Art At construction sites, road paving sites, civil engineering work sites, and the like, there are many work modes in which construction machines and workers intersect. In addition, depending on the location, general people also visit or carry in and carry out various machines used in association with work, and also obstacles. If these workers, ordinary people, obstacles, etc. are behind or diagonally obstructing the field of view of the driver of the work vehicle or the like, the risk of an accident is very high. Therefore, various safety systems have been conventionally proposed. One of them is a distance measurement method using microwaves or ultrasonic waves. This distance measuring method is a system that captures an echo from an object that reflects microwaves or ultrasonic waves to measure a distance, and issues an alarm of a level according to the measured distance to an object in an alarm area.

[0003]

The conventional alarm system utilizing the distance measuring method is not limited to workers, for example,
It has the drawback of generating an alarm in response to obstacles such as grass and trees, work equipment and devices that should not generate an alarm, and is not practical because it is alarm sensitive. In order to solve such a drawback, for example, a transponder method using microwaves has been proposed. The transponder system divides a driver and a worker into a master station and a slave station to exchange information.

The worker side, which is the slave station, is equipped with a device for receiving the microwaves transmitted from the vehicle side, which is the master station. Microwaves that have been switched and modulated are sent back to the main station. On the other hand, the vehicle that is the master station receives the signal from the slave station within the detection area, and when the modulated signal from the slave station is received, it is from the worker, and the unmodulated signal is received. Sometimes, it is detected that the reflected wave is received from an obstacle other than the worker.
Then, when a worker is detected within the danger range, the system issues a warning from the vehicle side.

However, in such a microwave transponder system, an antenna serving as a starting point for distance measurement is
Usually installed on the side of the work machine. Since the antenna of this microwave usually has a directivity of 90 degrees or less, there is a blind spot where the distance cannot be measured even near the antenna. Even if a plurality of antennas 2a and 2b are mounted on the same side surface of the vehicle 1 as shown in FIG. 2 to widen the monitoring range 2c, it is difficult to completely eliminate the blind spot 2d. Moreover, since this blind spot is very close to the work machine, it easily gets caught in the work machine and is a very dangerous place. It is a problem that a worker who enters such a dangerous area cannot detect it.
In addition, microwaves often have a phenomenon that the detection level of microwaves becomes low due to interference between transmitted waves and reflected waves and distance measurement cannot be performed, resulting in lack of detection reliability.

On the other hand, an ultrasonic distance measuring device generally has a short measuring distance and a narrow detection area. However, when trying to measure long distances to ensure a wide range of safety,
Since the propagation speed is limited, the measurement time per measurement becomes long and the detection performance deteriorates. Furthermore, if the sensitivity of the ultrasonic sensor is increased for long-distance measurement, even the sound generated by the operation of the work machine is erroneously detected.
This is rather a problem because it lowers safety and lowers work efficiency. The present invention solves the problems of the prior art as described above, and a work machine capable of reliably monitoring an operator or the like who should issue an alarm over a range from a long distance to a short distance. The purpose is to provide an alarm system.

[0007]

An alarm system for a work machine according to the present invention which achieves the above object has a first detector mounted on a predetermined side surface of the work machine or the like and has the first detection. The first range defined by the first detection angle having a predetermined width and the first maximum detection distance having a predetermined length depending on the characteristics of the child, and the detection target within the first range and the first range. A first distance measuring means for measuring a distance from the first detector;
A second detection angle wider than the first detection angle and a first maximum angle depending on a characteristic of the second detection element, the second detection element being mounted on the side surface of the work machine; Second distance measuring means for measuring the distance between the detection target and the second detector within the second range defined by the second maximum detection distance shorter than the detection distance; , And the detection target detected by the second detection unit even if the detection target is not detected by the first measurement unit is included in the monitoring target for issuing an alarm.

Specifically, a first radio wave transmitting / receiving device mounted on a work machine as a transponder type main station, and a radio wave transmitted from the first radio wave transmitting / receiving device mounted on an outer surface of the work machine. And a radio wave transmitter that emits a radio wave, and enters a predetermined radio wave monitoring range around the work machine that is restricted by the radio wave transmittable range of the radio wave transmitter, and is monitored by the master station as a slave station of the transponder system. The second radio wave transmission / reception device is mounted on the same surface as the mounting surface of the radio wave transmitter with respect to the work machine, and extends beyond the radio wave monitoring range toward the periphery of the mounting surface of the work machine. An ultrasonic transmitter that emits a sound wave; and an ultrasonic transceiver that detects the presence of an ultrasonic reflector by receiving the ultrasonic wave emitted through the ultrasonic transmitter, wherein the slave station is the master station. Station Even when it is outside the radio wave monitoring range, when it is within the proximity range of the radio wave transmitter mounting surface of the work machine, the ultrasonic wave transmitting / receiving device is detected as the ultrasonic wave reflector, thereby issuing an alarm. Are included in the monitoring target.

[0009]

As described above, slave stations located at medium and long distances from the work machine are monitored using microwaves that can be measured at high speed even over long distances. Is monitored using ultrasonic waves that can be detected in. Therefore, the worker or the like can be reliably monitored over a range from a long distance to a short distance of the work machine, and an appropriate alarm can be issued according to the distance.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of an embodiment to which an alarm system for a working machine according to the present invention is applied, and is a schematic plan view. Here, 1 is a hydraulic excavator as a working machine, 2
a and 2b are microwave antennas also serving as radio wave transmitters,
An ultrasonic sensor 3 also serves as an ultrasonic transmitter. Although the radio wave transmitting / receiving device and the ultrasonic wave transmitting / receiving device are mounted inside the hydraulic excavator 1, their illustration is omitted.

The antennas 2a and 2b are attached to, for example, substantially both ends of the rear surface of the hydraulic excavator 1. The microwaves from these antennas 2a and 2b are emitted to the rear of the hydraulic excavator with a relatively wide directional angle as a microwave, but still spread only about 90 degrees. On the other hand, there is a margin for measurable distance,
It is possible to sufficiently cover the turning range of the shovel. Then, when a worker enters the microwave reachable area 2c, the worker receives the microwave transmitted from the main station.

A helmet or the like of a worker to be monitored is provided with a transponder as a slave station. When the transponder receives a microwave from the master station, it modulates the microwave and returns it to the master station. By detecting the modulated microwave, the main station can properly distinguish the worker from other obstacles. Furthermore, by measuring the return time from the transponder, etc., the antennas 2a, 2b
And the distance between the transponder. This distance is used as the distance between the work machine and the worker, and the risk of the worker is estimated. Therefore, an appropriate alarm according to the degree of danger can be issued to the worker and the operator of the hydraulic excavator.

The ultrasonic sensor 3 is, for example, a hydraulic excavator 1.
It is attached to the center of the rear surface. That is, they are positioned at the centers of the blind spots of the microwaves from the antennas 2a and 2b on both ends of the same plane. Ultrasonic waves are emitted to the rear of the hydraulic excavator with a directivity angle of approximately 180 degrees, and obstacles and the like are detected in all rearward directions of the hydraulic excavator. In this way, the ultrasonic transmission / reception device via the ultrasonic sensor 3 sets the detection area 3a in substantially the entire vicinity of the rear surface of the hydraulic excavator 1 to cover the blind spot of microwave monitoring. Moreover, the maximum detection distance by ultrasonic waves may be considerably short corresponding to the blind spot of microwave monitoring. Therefore, since the measurement cycle can be shortened, the detection performance will not be impaired.

For the same reason, since the detection sensitivity of the ultrasonic sensor 3 can be lowered, the risk of erroneous detection is greatly reduced. Further, within the ultrasonic detection range 3a,
It is extremely close to the hydraulic excavator 1 and is extremely dangerous. For this reason, when something is detected within this range, an emergency level alarm may be issued without distinguishing the worker from other obstacles. Therefore, it is sufficient for the ultrasonic sensor 3 and the ultrasonic transmitting / receiving device to have a simple configuration. Moreover, even a worker who unfortunately leaked from the monitoring of the main station due to the interference of microwaves can be reliably detected by ultrasonic waves when approaching the hydraulic excavator,
Safety is improved.

The slave station transmitter / receiver may be attached to various obstacles, equipment, persons requiring monitoring, etc., in addition to the workers mentioned in the embodiment. Even if they are mixed, they can be monitored according to their respective risk levels. Further, in the embodiment, for simplification, a case has been described in which the entire reachable range of microwaves and ultrasonic waves is detected, but in reality, only a received signal in a certain range is extracted by applying a gate. This is to eliminate noise and unnecessary received signals.

[0016]

As can be understood from the above description, according to the present invention, the dead angle of the monitoring device using the microwave, which has a limited detection angle but can be measured at high speed over a long distance,
This is complemented by monitoring using ultrasonic waves, which is suitable for short-range and wide-angle detection. As a result, the monitoring target can be reliably detected over a range from a long distance to a short distance, and an appropriate alarm can be generated. As a result, it is possible to improve the safety of the work machine and improve the work efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment to which an alarm system for a work machine according to the present invention is applied.

FIG. 2 is an application example of a conventional warning system for a working machine using microwaves.

[Explanation of symbols]

 1 Hydraulic excavator 2a, 2b Microwave antenna 3 Ultrasonic sensor

Claims (2)

[Claims] 1. A first detector mounted on a predetermined surface of a work machine, having a first detection angle of a predetermined width and a predetermined length depending on the characteristics of the first detector. A first distance measuring means for measuring a distance between the first detection element and a detection target within the first range determined by the first maximum detection distance; and the working machine. A second detection angle, which has a second detection element mounted on the side surface, is wider than the first detection angle, and is larger than the first maximum detection distance, depending on the characteristics of the second detection element. A second range which is defined by a short second maximum detection distance, and second distance measuring means for measuring a distance between the detection target and the second detector within the second range, Even if the detection target is not detected by the first measuring unit, the detection detected by the second detecting unit Elephant, work machine alarm system, characterized in that are monitored for issuing an alarm. 2. A first radio wave transmission / reception device mounted on a work machine as a main station of a transponder system, and a radio wave transmitter mounted on the outer surface of the work machine to emit a transmission radio wave from the first radio wave transmission / reception device. And a second radio wave transmission / reception that is a monitoring target of the main station as a slave station of the transponder system when it enters a predetermined radio wave monitoring range around the work machine which is restricted by the radio wave transmittable range of the radio wave transmitter. An ultrasonic wave that is mounted on the same surface as the mounting surface of the radio wave transmitter with respect to the device and the working machine, and that emits ultrasonic waves at a wider angle than the radio wave monitoring range toward the periphery of the mounting surface of the working machine. A transmitter and an ultrasonic transmitter / receiver that detects the presence of an ultrasonic reflector by receiving ultrasonic waves emitted via the ultrasonic transmitter, wherein the slave station monitors the radio wave of the master station. Example Even if it is outside, when it is within the proximity range of the radio wave transmitter mounting surface of the work machine, it is detected as the ultrasonic reflector by the ultrasonic transmission / reception device, so that a monitoring target for issuing an alarm An alarm system for work machines characterized by the following.