Patent Description:
In order to ensure safety of a worker working near a construction machine, a technique for emitting an alarm such as by sound and light when the worker and the construction machine come close to each other, as disclosed in <CIT> (Patent Document <NUM>).

<CIT> discloses an emergency automotive braking system in which a vehicle brake is movable between a braking position and a non-braking position. An electrically powered actuator is mechanically coupled to the vehicle brake and, when energized, moves the vehicle brake from the non-braking and to the braking position. A charging circuit electrically charges a capacitor bank. A collision avoidance system generates a trigger output signal upon detection of a potential vehicle collision to a control system which, in response to the trigger signal, electrically connects the capacitor bank to the actuator to energize the actuator.

<CIT> discloses a self-contained automatic control system for a vehicle to avoid collision thereof with an obstacle. The system comprises: a combined transmitter-receiver means for producing and emitting a high frequency radio signal and for receiving the reflection of such signal from an obstacle; amplification means; means producing a signal having a relatively low frequency equal to the difference in frequency between the signal emitted by said transmitter and the signal received by said receiver, said low frequency signal being fed to said amplification means; means controlled by the signal from said amplification means for operating said vehicle controls as a function of the distance of said vehicle from an obstacle reflecting signals from said transmitter to said receiver and as a function of the relative speed with which said vehicle approaches said obstacle; control means associated with said vehicle speed responsive mechanism and said amplification means for making actuation of said vehicle controls responsive to the speed of said vehicle, whereby said automatic control system governs deceleration and stopping of said vehicle responsive to its absolute speed and its distance and rate of closure with respect to said obstacle.

<CIT> discloses a safety device for public works vehicles. The safety device is intended to be used on vehicles equipped with brakes actuated by master cylinders connected into a main pneumatic circuit powered by a compressed air source. The device includes detection and signalling means which are actuated by an obstacle encountered in the path of the vehicle. It further includes emergency stop control means for the vehicle which are controlled by the detection means. The emergency stop control means include an auxiliary pneumatic circuit connected in parallel with the main circuit and comprising a relay valve for actuating the master cylinders which is normally closed and is controlled by the detection means with the aid of a solenoid valve linked to the compressed air source.

However, a sound alarm cannot be used during nighttime work for fear of complaints about noise, which sometimes makes it difficult to ensure the safety of a worker. Also, the awareness level of the alarm is decreased as the operator of the construction machine or the worker become accustomed to the alarm sound, and there is a possibility that the safety of the worker cannot be ensured.

Thus, it is an object of the present invention to provide an apparatus and a method for stopping a construction machine in an emergency, which is capable of ensuring the safety of the worker working around the construction machine.

The literal scope of the present invention is set out in the appended claims.

In order to solve the problem, an emergency stop apparatus for a working machine comprises: a detecting device for detecting an obstacle intruding into a predetermined area around the working machine; an actuator fixed to a vehicle body of the working machine or a member attached to the vehicle body; a coupling member for coupling an output shaft of the actuator and a brake pedal; and an electronic control unit. The electronic control unit actuates the actuator and moves the brake pedal in an actuation direction of a service brake when the obstacle is detected by the detecting device. The emergency stop apparatus is characterized in that the actuator is a power cylinder and the emergency stop apparatus further comprises a member to be detected mounted on an output shaft of the power cylinder (<NUM>); and at least one sensor for detecting the member to be detected, the at least one sensor fixed to the vehicle body of the working machine or a member attached to the vehicle body such that a position relative to an expansion and contraction direction of the output shaft of the power cylinder is adjustable,
wherein the electronic control unit controls an actuation area of the power cylinder in response to an output signal of the at least one sensor.

Additionally, in an emergency stop method for a working machine, when an electronic control unit which is capable of reading an output signal of a detecting device for detecting an obstacle intruding into a predetermined area around the construction machine and capable of outputting a driving signal to an actuator for moving a brake pedal in an actuation direction of the service brake detects an obstacle intruding into the predetermined area, the electronic control unit outputs the driving signal to the actuator to move the brake pedal in an actuation direction of the service brake to stop the working machine in an emergency. The method is characterized in that the actuator is a power cylinder and a member to be detected is mounted on an output shaft of the power cylinder and at least one sensor for detecting the member to be detected is fixed to a vehicle body of the working machine or a member attached to the vehicle body such that a position relative to an expansion and contraction direction of the output shaft of the power cylinder is adjustable; and wherein the electronic control unit is configured to control an actuation area of the power cylinder in response to an output signal of the at least one sensor.

According to the present invention, the safety of a worker who works around the construction machine can be ensured.

Hereinbelow, embodiments for implementing the present invention will be described in detail with reference to the accompanying drawings.

<FIG> illustrates an example of a wheel loader <NUM> which uses a bucket attached to a tip of the vehicle body to scoop gravel or crushed stones and lade them on such as a dump truck. The wheel loader <NUM> is an example of the construction machine.

The wheel loader <NUM> includes a front vehicle body <NUM> and a rear vehicle body <NUM>. The front vehicle body <NUM> and the rear vehicle body <NUM> are foldably joined to each other through a vertically extending center pin <NUM>.

A pair of right and left front wheels <NUM> having rubber tires and wheel disks, for example, are fixed to a front lower part of the front vehicle body <NUM>. Additionally, base end portions of a pair of right and left lift arms <NUM> are rotatably fixed about a laterally extending axis at opposite sides of the front vehicle body <NUM>. A laterally extending bucket <NUM> is rotatably fixed about a laterally extending axis at a tip section of the pair of right and left lift arms <NUM>. The tip sections of a pair of right and left arm cylinders (not shown), having base end portions swingably fixed to the front vehicle body <NUM>, are rotatably fixed about a laterally extending axis at intermediate portions of the pair of right and left lift arms <NUM>.

Furthermore, the end of a tilt rod <NUM> is rotatably fixed about a laterally extending axis at the rear central portion of the bucket <NUM>. The end of a tilt arm <NUM>, having an intermediate portion swingably fixed relative to the front vehicle body <NUM>, is rotatably fixed about a laterally extending axis at another end of the tilt rod <NUM>. The tip section of the bucket cylinder <NUM>, having a base end portion swingably fixed relative to the front vehicle body <NUM>, is rotatably fixed about a laterally extending axis at the other end of the tilt arm <NUM>.

Accordingly, the height of the bucket <NUM> can be changed by extending and retracting the arm cylinders to move the tip sections of the pair of right and left lift arms <NUM> up and down. Additionally, the angle of the bucket <NUM> relative to the pair of right and left lift arms <NUM> can be changed through the tilt arm <NUM> and the tilt rod <NUM> by extending and retracting the bucket cylinder <NUM>. Therefore, the height and posture of the bucket <NUM> relative to the front vehicle body <NUM> can be changed by appropriately controlling the arm cylinders and bucket cylinder <NUM>.

A pair of right and left rear wheels <NUM> having rubber tires and wheel disks, for example, is fixed at a central lower part of the rear vehicle body <NUM>. Additionally, an engine as a prime mover (not shown) is loaded above the rear vehicle body <NUM>, and an engine hood <NUM> for covering the upper surface and opposite sides of the engine is mounted in an openable and closable manner. In front of the engine, a fuel tank <NUM> for storing engine fuel is fixed in a state in which an oil filling port is exposed outside. At a back of the rear vehicle body <NUM>, there is loaded a counter weight <NUM> for suppressing the back of the wheel loader <NUM> to be lifted when gravel or crushed stones, etc. are scooped by the bucket <NUM>.

Furthermore, the base end portions of a pair of right and left steering cylinders <NUM> are rotatably fixed about a vertically extending axis at the rear vehicle body <NUM>. The tip sections of the pair of steering cylinders <NUM> are rotatably fixed about a vertically extending axis at two spaced-apart positions at the back of the front vehicle body <NUM>. Accordingly, when the pair of right and left steering cylinders <NUM> are actuated such that one of the steering cylinders is extracted and another one is retracted, the front vehicle body <NUM> folds relative to the rear vehicle body <NUM>, and the wheel loader <NUM> can be steered. Additionally, a driver stand <NUM> for the operator of the wheel loader <NUM> is fixed at the front upper surface of the rear vehicle body <NUM>.

The engine loaded on the rear vehicle body <NUM> generates a hydraulic pressure for causing the arm cylinders, bucket cylinder <NUM> and steering cylinders <NUM> to work, and drives the front wheels <NUM> of the front vehicle body <NUM> and the rear wheels <NUM> of the rear vehicle body <NUM>. Here, the front wheels <NUM> and rear wheels <NUM> may also be driven by the hydraulic pressure.

<FIG> illustrates an example of an emergency stop apparatus <NUM> loaded on the wheel loader <NUM>. The emergency stop apparatus <NUM> is broadly divided into a detecting device <NUM> for detecting an obstacle intruding into a predetermined area around the wheel loader <NUM>, a driving device <NUM> for moving a brake pedal BP of the wheel loader <NUM> in an actuation direction of the service brake, and an electronic control unit <NUM> with a built-in microcomputer.

The detecting device <NUM> is mounted on a predetermined place of the wheel loader <NUM>, for example, at the rear upper part of the rear vehicle body <NUM>. Additionally, the detecting device <NUM> detects an obstacle intruding into a predetermined area around the wheel loader <NUM>, specifically, the obstacle intruding into the predetermined area behind the wheel loader <NUM>. The predetermined area for detecting the obstacle is, for example, between <NUM>-<NUM> width and <NUM>-<NUM> from the wheel loader <NUM>, preferably <NUM>-<NUM> from the wheel loader <NUM>, although it may vary according to site situation and the like.

A stereo camera with excellent water resistance, stain resistance and dust resistance, such as "BLAXTAIR (Trademark)" sold by EUREKA Ltd. , can be used as the detecting device <NUM>. The detecting device <NUM>, as shown in <FIG>, can arbitrarily switch detecting either a person (such as a pedestrian and a worker) or some other objects in the area A located closest to the wheel loader <NUM> and detecting only a person in the area B which is located more distant from the area A. When the stereo camera is used as the detecting device <NUM>, a monitor may be installed in the driver stand <NUM> of the wheel loader <NUM> to display an image taken by the stereo camera on a monitor.

Examples of the obstacle are a person and other objects. Additionally, the detecting device <NUM> processes an image taken by the camera to detect the obstacle, and thus, the detecting device <NUM> may be equipped with a function which can freely set the detecting area of the obstacle.

The driving device <NUM> has an actuator <NUM> fixed to the rear vehicle body <NUM> or a member attached to the rear vehicle body <NUM> (for example, a bracket), and a coupling member <NUM> for coupling an output shaft of the actuator <NUM> and the brake pedal BP. Here, it is desirable to use an electric actuator as the actuator <NUM> so as to be easily retrofitted to the wheel loader <NUM>.

The electronic control unit <NUM>, as shown in <FIG>, incorporates a processor 560A such as a CPU (central processing unit), a nonvolatile memory 560B, a volatile memory 560C, an input and output circuit 560D, and a bus 560E for communicatively connecting them. The nonvolatile memory 560B, for example contains such as an electrically data rewritable flash ROM (read only memory), and stores such as a control program and a control variable of the emergency stop apparatus <NUM>. The volatile memory 560C, for example, contains a dynamic RAM (random access memory), and provides a temporal storage area in an arithmetic process of the processor 560A. The input and output circuit 560D, for example, contains an IC (integrated circuit), and provides input and output functions of the analog and digital signals with external equipment. Additionally, as shown in <FIG>, a buzzer <NUM> for notifying intrusion of the obstacle in a predetermined area, and a switch <NUM> for switching a detection area of the obstacle between the area A and area B, are mounted on a housing of the electronic control unit <NUM>. The switch <NUM> may also switch the detection area of the obstacle between the area B and both of the areas A and B.

The electronic control unit <NUM>, upon receiving an obstacle detection signal from the detecting device <NUM>, outputs a driving signal to the actuator <NUM> of the driving device <NUM>, and actuates the buzzer <NUM> mounted on the housing. In short, when the obstacle is detected by the detecting device <NUM>, the electronic control unit <NUM> actuates the actuator <NUM> to move the brake pedal BP in an actuation direction of the service brake. When the brake pedal BP is moved in the actuation direction, even if the operator of the wheel loader <NUM> does not step on the brake pedal BP, the service brake (not shown) is actuated to perform braking so that the wheel loader <NUM> can be emergency stopped. At this time, in order to suppress the back of the wheel loader <NUM> to be lifted by inertia, it is desirable for the electronic control unit <NUM>, for example, to gradually move the brake pedal BP from an unactuated position to an actuated position of the service brake over a predetermined time, for example, <NUM> to <NUM> second.

Accordingly, even if the operator cannot recognize the obstacle intruding in a travel direction due to such as a blind spot and noise when the wheel loader <NUM> is moving backward, the service brake is automatically actuated through the brake pedal BP upon detection of the obstacle in the predetermined area, and enables the wheel loader <NUM> to stop in emergency. For this reason, even if, for example, the worker concentrates on work and fails to recognize that the wheel loader <NUM> approaches, the wheel loader <NUM> automatically stops so that the safety of the worker working around the wheel loader <NUM> can be secured. Here, the electronic control unit <NUM> can control the actuator <NUM> of the driving device <NUM> such that the emergency stop apparatus <NUM> is actuated only when the wheel loader <NUM> moves backward.

If the wheel loader <NUM> stops in emergency, in response to the operator pressing the switch (not shown), for example, the electronic control unit <NUM> may actuate the actuator <NUM> of the driving device <NUM> in an opposite direction so as to bring the brake pedal BP back to the unactuated position of the service brake.

Here, various embodiments of the driving device <NUM> will be explained.

In the explanations hereunder, in order to avoid confusion among the embodiments, the driving device will be explained with a new reference number.

<FIG> and <FIG> illustrate the driving device <NUM> according to an example not belonging to the invention. The driving device <NUM> has an electric motor <NUM> as an example of the actuator, a fixing member <NUM>, and a linear member <NUM> such as a chain or a wire having flexibility.

The electric motor <NUM> is, for example, fixed in a state in which an output shaft extends in the lateral direction to a floor panel FP of the back side of the brake pedal BP. The fixing member <NUM> is a member that can fix the brake pedal BP by sandwiching the brake pedal BP, and has, for example, a pair of plate members for sandwiching the brake pedal BP from the front and the back, and a bolt, a washer and a nut for coupling the pair of plate members in the thickness direction. Additionally, a ring 620A for connecting the linear member <NUM> is fixed to a surface of the fixing member <NUM> located at the back side of the brake pedal BP. The ring 620A may be substituted with a protrusion, for example. The linear member <NUM> is wound onto the output shaft of the electric motor <NUM>, and a free end of the linear member <NUM> is connected to the ring 620A of the fixing member <NUM>. At this time, the linear member <NUM> couples the electric motor <NUM> with the fixing member <NUM> so as not to obstruct the operator stepping on the brake pedal BP in the unactuated state of the emergency stop apparatus <NUM> (the same applies hereafter). Here, combination of the fixing member <NUM> and linear member <NUM> is the example of the coupling member.

According to the driving device <NUM> of the example when the operator of the wheel loader <NUM> steps on the brake pedal BP in the unactuated state of the emergency stop apparatus <NUM>, the linear member <NUM> slackens, so that it does not hinder the operation of the brake pedal BP. Accordingly, the operator of the wheel loader <NUM> can actuate the service brake by stepping on the brake pedal BP at will.

On the other hand, when the obstacle intrudes into a predetermined area located behind the wheel loader <NUM>, the electric motor <NUM> rotates, and as shown in <FIG>, the linear member <NUM> is wound onto the output shaft. When the linear member <NUM> is wound onto the output shaft of the electric motor <NUM>, the relative distance between the electric motor <NUM> and the fixing member <NUM> is shortened, and the brake pedal BP is pulled in the electric motor <NUM> direction to actuate the service brake.

<FIG> and <FIG> illustrate a driving device <NUM> according to a first embodiment of the present invention. The driving device <NUM> has a power cylinder <NUM> as an actuator, a fixing member <NUM>, and a linear member <NUM>. At a back side of the brake pedal BP and through a bracket BK rising upward from the floor panel FP, the power cylinder <NUM> is fixed in a state in which the output shaft is located below. A ring <NUM> for connecting the linear member <NUM> is mounted on a tip section of the output shaft of the power cylinder <NUM>. The ring <NUM> may be substituted with a protrusion, for example. The fixing member <NUM>, which is the same as the previous first embodiment, will not be explained in order to avoid duplicate explanation. See the previous explanation in the example, if necessary (the same applies hereafter). An end of the linear member <NUM> is connected to the ring <NUM> mounted on the output shaft of the power cylinder <NUM>, and another end of the linear member <NUM> is connected to a ring 670A of the fixing member <NUM>. Here, combination of the fixing member <NUM> and linear member <NUM> is the example of the coupling member.

According to the driving device <NUM> of the first embodiment, when the operator of the wheel loader <NUM> steps on the brake pedal BP in the unactuated state of the emergency stop apparatus <NUM>, the linear member <NUM> slackens, so that it does not hinder the operation of the brake pedal BP. Accordingly, the operator of the wheel loader <NUM> can actuate the service brake by stepping on the brake pedal BP at will.

On the other hand, when the obstacle intrudes into a predetermined area located behind the wheel loader <NUM>, the output shaft of the power cylinder <NUM> extends, and as shown in <FIG>, an end of the linear member <NUM> moves in the floor panel FP direction, that is, the direction away from the brake pedal BP. When the end of the linear member <NUM> moves in the floor panel FP direction, the other end of the linear member <NUM> also moves in the floor panel FP direction, because the linear member <NUM> has a constant length. When the other end of the linear member <NUM> moves in the floor panel FP direction, the brake pedal BP is pulled in the floor panel FP direction to actuate the service brake.

<FIG> illustrate a driving device <NUM> according to a second embodiment. The driving device <NUM> has a power cylinder <NUM> as an actuator, a link mechanism <NUM>, a fixing member <NUM>, and a linear member <NUM>. At a back side of the brake pedal BP, the power cylinder <NUM> is fixed to a floor panel FP in a state in which an axial line extends in the lateral direction. The link mechanism <NUM> has a vertically extending rotating shaft 720A, a first lever 720B fixed to an intermediate portion of the rotating shaft 720A in a cantilevered state, a second lever 720C fixed to an upper end section of the rotating shaft 720A in a cantilevered state, and a holder 720D fixed to the floor panel FP and rotatably pivotally supports the rotating shaft 720A.

A free end of the first lever 720B is rotatably fixed to the output shaft of the power cylinder <NUM> through a pin member 720E vertically extending like the rotating shaft 720A. The second lever 720C is, for example, fixed to the rotating shaft 720A at an angle of substantially <NUM> degrees to the first lever 720B in a side view, and a ring 720F for connecting the linear member <NUM> is fixed to a free end of the second lever 720C. An end of the linear member <NUM> is connected to a ring 720F of the second lever 720C, and another end of the linear member <NUM> is connected to a ring 730A of the fixing member <NUM>. The first lever 720B and second lever 720C are not limited to the separate type levers but can be an integrated lever having an L shape in a side view. Here, combination of the fixing member <NUM> and linear member <NUM> is the example of the coupling member.

According to the driving device <NUM> of the second embodiment, when the operator of the wheel loader <NUM> steps on the brake pedal BP in the unactuated state of the emergency stop apparatus <NUM>, the linear member <NUM> slackens, so that it does not hinder the operation of the brake pedal BP. Accordingly, the operator of the wheel loader <NUM> can actuate the service brake by stepping on the brake pedal BP at will.

On the other hand, when the obstacle intrudes into a predetermined area located behind the wheel loader <NUM>, the output shaft of the power cylinder <NUM> extends, and as shown in <FIG> and <FIG>, the rotating shaft 720A rotates through the first lever 720B of the link mechanism <NUM>. When the rotating shaft 720A rotates, the second lever 720C which extends in a direction different from the first lever 720B rotates in a direction away from the brake pedal BP. When the second lever 720C rotates, the free end of the second lever 720C moves away from the brake pedal BP so that the brake pedal BP is pulled in the floor panel FP direction through the linear member <NUM> to actuate the service brake.

Accordingly, as can be easily understood by comparing <FIG> with <FIG>, the link mechanism <NUM> exercises a function which changes the actuation direction (expansion and contraction direction) of the power cylinder <NUM> by substantially <NUM> degrees, so that it can handle a small-sized wheel loader <NUM> having a smaller space for installing the emergency stop apparatus <NUM>, for example. A distance for pulling the brake pedal BP can be changed by differentiating the length or angle of the first lever 720B and second lever 720C.

<FIG> and <FIG> illustrate a driving device <NUM> according to a third embodiment. The driving device <NUM> has a power cylinder <NUM> as an actuator, and a pressing member <NUM>. A base end portion of the power cylinder <NUM> is swingably fixed in a position facing a surface of the brake pedal BP, that is, a surface to be stepped on by the operator, about a laterally extending axis within a predetermined angle through, for example, a bracket (not shown) which is fixed to an inner panel of the driver stand <NUM>. Additionally, a pressing member <NUM>, which is capable of being contacted with and separated from a surface of the brake pedal BP and having an elastic member such as one of rubber affixed to a joint surface of the brake pedal BP, for example, is fixed to a tip section of the output shaft of the power cylinder <NUM>. The pressing member <NUM> can be any shape such as a channel shape (U shape), a rectangular parallelepiped shape, a cylindrical shape, and a hemispherical shape, for example, for sandwiching opposite sides of the brake pedal BP. Here, the pressing member <NUM> is the example of the coupling member.

According to the driving device <NUM> of the third embodiment, when the operator of the wheel loader <NUM> steps on the brake pedal BP in the unactuated state of the emergency stop apparatus <NUM>, the pressing member <NUM> can be contacted with and separated from brake pedal BP, and thus, even if the driving device <NUM> is in the unactuated state, it does not hinder the operation of the brake pedal BP. Accordingly, the operator of the wheel loader <NUM> can actuate the service brake by stepping on the brake pedal BP at will.

On the other hand, when the obstacle intrudes into a predetermined area located behind the wheel loader <NUM>, the output shaft of the power cylinder <NUM> extends, and as shown in <FIG>, the pressing member <NUM> pushes the brake pedal BP to actuate the service brake. At this time, a base end portion of the power cylinder <NUM> is swingably fixed in a predetermined area, and thus, the power cylinder <NUM> also swings according to the rotation of the brake pedal BP to suppress the pressing member <NUM> to be removed from the surface of the brake pedal BP.

In the case of a hanging brake pedal BP, as shown in <FIG> and <FIG>, the power cylinder <NUM> can also press the pedal arm PA through the pressing member <NUM>. That is, the power cylinder <NUM> may press the brake pedal BP or a movable member attached to the brake pedal BP to actuate the service brake.

In the case if the emergency stop apparatus <NUM> is retrofitted to the existing wheel loader <NUM>, an operation angle of the brake pedal BP may be different according to for example the specification and size of the wheel loader <NUM>. Thus, as shown in <FIG> and <FIG>, a member <NUM> to be detected extended in a perpendicular direction relative to an axial line of the output shaft is mounted on an output shaft of the power cylinder <NUM>, for example. Additionally, a first sensor <NUM> and a second sensor <NUM> such as a proximity switch and a limit switch, for example, are mounted on a rear vehicle body <NUM> or a member attached to the rear vehicle body <NUM>. Here, the member <NUM> to be detected consists of a member which is detectable by the first sensor <NUM> and second sensor <NUM>, and can be any shape such as an annular shape, a cube shape and a lever shape, for example.

The first sensor <NUM>, as shown in <FIG>, is mounted on a position for detecting the member <NUM> to be detected when in the state in which the output shaft of the power cylinder <NUM> is contracted and the service brake is released. The second sensor <NUM>, as shown in <FIG>, is mounted on a position for detecting the member <NUM> to be detected when in the state in which the output shaft of the power cylinder <NUM> is extended and the service brake is actuated.

Each output signal of the first sensor <NUM> and second sensor <NUM> is input to the electronic control unit <NUM>. The electronic control unit <NUM>, at the time of extending the output shaft of the power cylinder <NUM>, stops actuating the power cylinder <NUM>, if the second sensor <NUM> detects the member <NUM> to be detected. Additionally, the electronic control unit <NUM>, at the time of contracting the output shaft of the power cylinder <NUM>, stops actuating the power cylinder <NUM>, if the first sensor <NUM> detects the member <NUM> to be detected.

Accordingly, the actuation area of the power cylinder <NUM> can be changed arbitrarily by mounting the first sensor <NUM> and second sensor <NUM> to positions adapted for the characteristics of the wheel loader <NUM>. For this reason, it is possible to easily handle different operation angles of the brake pedal BP according to the specification and size of the wheel loader <NUM>. The actuation area of the power cylinder <NUM> defines at least one of the state in which the output shaft is contracted and the service brake is released, and the state in which the output shaft is extended and the service brake is actuated.

At this time, in order to be able to adjust the mounting positions of the first sensor <NUM> and second sensor <NUM>, for example, a long hole, which extends in a direction in which the output shaft of the power cylinder <NUM> is extended and contracted, is formed at a bracket attached to the power cylinder <NUM>, and the first sensor <NUM> and second sensor <NUM> may be mounted by using the long hole. By doing so, the mounting positions of the first sensor <NUM> and second sensor <NUM> can be changed freely within the area of the long hole, even if the member adapted for the characteristics of the wheel loader <NUM> is not used.

The detecting device <NUM> is not limited to the stereo camera provided with a function for detecting an obstacle in the predetermined area, but the technique disclosed in <CIT>, which is previously presented by the Applicant, may be used. That is, the detecting device <NUM>, as shown in <FIG>, has two magnetic field generators 520A, an IC tag 520B worn by a worker <NUM> who works around the wheel loader <NUM>, and a receiver 520C for receiving radio waves emitted from the IC tag 520B responsive to the magnetic field generated by the magnetic field generators 520A.

The two magnetic field generators 520A, which are installed in the right and left end portions at the back of the wheel loader <NUM>, generates a magnetic field in the predetermined area C behind the wheel loader <NUM> as shown in <FIG>. Here, the two magnetic field generators 520A are controlled by the electronic control unit <NUM>, and the predetermined area C for generating the magnetic field can be changed freely, for example, by changing the magnetic field strength according to the control signal from the electronic control unit <NUM>.

The IC tag 520B can suppress consumption of the built-in battery by adopting a semi-active type which is activated upon detection of the magnetic field. Additionally, since the IC tag 520B is small and light in weight, the IC tag 520B can be mounted on a helmet of the worker <NUM>, and can be placed in a pocket of the worker <NUM>. The receiver 520C is mounted on a central portion at the back of the wheel loader <NUM>, and an output signal of the receiver 520C is input to the electronic control unit <NUM>.

The electronic control unit <NUM> monitors the output signal of the receiver 520C, and detects, for example, radio waves emitted from the IC tag 520B in response to the change. The electronic control unit <NUM>, upon detection of the radio waves emitted from the IC tag 520B, determines that the worker <NUM> intrudes into the predetermined area C behind the wheel loader <NUM> to actuate the emergency stop apparatus <NUM>.

Claim 1:
An emergency stop apparatus (<NUM>) for a working machine (<NUM>), comprising:
a detecting device (<NUM>) for detecting an obstacle intruding into a predetermined area around a working machine (<NUM>);
an actuator (<NUM>) fixable to a vehicle body (<NUM>, <NUM>) of the working machine (<NUM>) or a member attached to the vehicle body (<NUM>, <NUM>);
a coupling member (<NUM>) for coupling an output shaft of the actuator (<NUM>) and a brake pedal (BP);
an electronic control unit (<NUM>) for actuating the actuator (<NUM>) and moving the brake pedal (BP) in an actuation direction of a service brake when the obstacle is detected by the detecting device (<NUM>); and
characterised in that the actuator is a power cylinder (<NUM>) and the emergency stop apparatus (<NUM>) further comprises:
a member (<NUM>) to be detected mounted on an output shaft of the power cylinder (<NUM>); and
at least one sensor (<NUM>, <NUM>) for detecting the member (<NUM>) to be detected, the at least one sensor (<NUM>, <NUM>) fixable to the vehicle body (<NUM>, <NUM>) of the working machine (<NUM>) or a member attached to the vehicle body (<NUM>, <NUM>) such that an actuation area of the power cylinder (<NUM>) defines at least one of a state in which the output shaft is contracted and the service brake is released, and a state in which the output shaft is extended and the service brake is actuated;
wherein the actuation area of the power cylinder (<NUM>) can be changed arbitrarily by mounting the at least one sensor (<NUM>, <NUM>) to positions adapted for the characteristics of the working machine; and
wherein the electronic control unit (<NUM>) controls the actuation of the power cylinder (<NUM>) in response to an output signal of the at least one sensor (<NUM>, <NUM>).