JP2000291435A - Construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fire extinguishing efficiency by injecting extinguishant in a required range, immediately after the inside of a housing cover reaches an abnormally high temperature. SOLUTION: This device is structured, such that a fan stopping device 20 forcing the rotation of a cooling fan stop almost as soon as a fire extinguishing device injects extinguishant is provided between a drive shaft of an engine 7 and a hub member 11 of a cooling fan 10. This structure allows the fan stopping device 20 to stop the cooling fan 10, independently of an operation state of the engine 7, thereby stopping the flow of cooling wind inside a housing cover, when the inside of the housing cover reaches an abnormally high temperature. Thus, extinguishant can be properly injected inside the housing cover, when the inside of the housing cover reaches an abnormally high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction machine such as a hydraulic shovel and a hydraulic crane, and more particularly to a construction machine having a fire extinguisher in a building cover.

[0002]

2. Description of the Related Art In general, a construction machine such as a hydraulic shovel or a hydraulic crane includes a lower traveling body and an upper revolving body rotatably provided on the lower traveling body. A working device for performing excavation work and the like is provided so as to be able to move up and down.

[0003] Further, the upper revolving superstructure comprises a revolving frame, a building cover provided on the revolving frame, an engine mounted on the frame and located in the building cover, and provided in the building cover. Heat exchanger, a cooling fan driven by the engine and supplying cooling air to the heat exchanger, and a fire extinguisher provided in the building cover and injecting a fire extinguisher into the building cover. .

[0004] The reason why the construction machine according to the prior art having such a structure is provided with a fire extinguisher is that this kind of construction machine is provided with an engine for operating various actuators for driving fuel and working equipment and the like. Oils and fats such as hydraulic oil and lubricating oil are used. When these construction machines start operating, the exhaust pipe of the engine becomes hot,
When the wiring connection of the electric system is loosened or damaged during long-term operation, the wiring connection may cause a contact failure or the like and a short circuit may occur in some cases. For this reason, management of oils and fats, inspection of oil and fat piping, cleaning of dust accumulated in the machine, and inspection and maintenance of electrical wiring and other connection parts are performed on a daily basis. In some cases, a fire may not occur if dust or the like containing water is accumulated. Therefore, this type of construction machine is provided with a fire extinguisher in case of emergency.

Therefore, in the event of a fire, for example, if an operator operates a manual switch provided in the cab or a temperature switch provided in the building cover detects an abnormally high temperature, the fire is extinguished. The device is operated and fire extinguishing agent is injected.

[0006]

By the way, in the construction machine according to the prior art described above, when the inside of the building cover becomes abnormally high, the fire extinguisher operates to inject fire extinguishing agent into the inside of the building cover.

However, since the cooling air is supplied to the heat exchanger such as the radiator by the cooling fan in the building cover, even if the fire extinguishing agent is injected into the building cover, the injected fire extinguishing agent is blown off by the cooling air. There is a problem that fire extinguishing cannot be performed efficiently.

Therefore, when injecting a fire extinguishing agent from a fire extinguisher, it is conceivable to stop the engine, wait for the cooling fan to stop, and then inject the fire extinguishing agent. There is a problem that it takes a long time from the start of the fire extinguishing operation to the fire extinguishing operation, and the delay in the fire extinguishing operation may increase damage.

The present invention has been made in view of the above-mentioned problems of the prior art. It is an object of the present invention to immediately extinguish a fire extinguisher into a desired range after a fire has occurred, thereby improving fire extinguishing efficiency. An object of the present invention is to provide such a construction machine.

[0010]

According to the present invention, there is provided a construction machine comprising: a frame; a building cover provided on the frame; an engine mounted in the building cover and mounted on the frame; A heat exchanger provided in the cover,
A cooling fan that is driven by the engine and supplies cooling air to the heat exchanger; and a fire extinguisher that injects a fire extinguishing agent into the building cover when the inside of the building cover becomes extremely hot.

Then, in order to solve the above-mentioned problem,
A feature of the structure adopted by the invention of claim 1 is that a fan stop device for forcibly stopping the rotation of the cooling fan almost simultaneously with the fire extinguishing device injecting the fire extinguishing agent is provided.

With this configuration, when the temperature inside the building cover becomes extremely high, the fan stop device forcibly stops the rotation of the cooling fan almost simultaneously with the fire extinguishing device injecting the fire extinguishing agent. The flow of the cooling air in the building cover can be stopped. As a result, the fire extinguishing agent can be immediately injected into a desired range, and the fire can be extinguished in a short time.

According to the second aspect of the present invention, the fan stop device is provided coaxially with the hub member of the cooling fan and transmits a rotation of the engine to the cooling fan, and the rotation transmitting member and the hub of the cooling fan. The clutch mechanism is configured to fasten and disengage members from each other, and a clutch actuating mechanism that is actuated by a signal from the outside when the inside of the building cover becomes abnormally high temperature and releases the fastening of the clutch mechanism. It is in.

With this configuration, during normal operation, since the clutch mechanism fastens the rotation transmitting body and the hub member of the cooling fan, the cooling fan rotates together with the rotation transmitting body, and heat exchange occurs. Supply cooling air to the vessel. On the other hand, when the clutch operating mechanism is activated by an external signal, the engagement of the clutch mechanism is released by the fan stopping device, so that the rotation of the cooling fan can be stopped regardless of the operating state of the engine.

According to a third aspect of the present invention, the clutch operating mechanism comprises an electromagnetic actuator and an operating member which is operated by the electromagnetic actuator to release the engagement of the clutch mechanism.

With this configuration, power is supplied to the electromagnetic actuator, and the operating member is operated to release the engagement of the clutch mechanism by the operating member.

According to the fourth aspect of the present invention, the operating member includes
There is provided an inertial rotation stop portion that engages with the hub member of the cooling fan to stop the inertial rotation of the cooling fan.

With this configuration, the coasting rotation of the cooling fan can be forcibly stopped by engaging the coasting rotation stopping portion with the hub member of the cooling fan.

According to the fifth aspect of the present invention, the clutch operating mechanism is configured to be activated by a signal from a manual switch operated by an operator or a temperature sensor provided in the building cover and detecting the temperature in the building cover. It is in.

With this configuration, the clutch operating mechanism can be operated by a signal transmitted from a manual switch or a temperature sensor provided in the building cover, and the fan stop device is operated in synchronization with the fire extinguishing device. be able to.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A construction machine according to an embodiment of the present invention will be described in detail with reference to FIGS.

Reference numeral 1 denotes a lower traveling body, and 2 denotes an upper revolving body mounted on the lower traveling body 1 so as to be pivotable.
A cab 4 provided on the front left side of the turning frame 3 via a cab bed 4A; a building cover 5 provided on the rear side of the cab 4; A work weight (not shown) is mounted on the front side of the upper swing body 2 so as to be able to move up and down.

Here, the turning frame 3 has a front,
Two vertical plates 3A, 3A extending rearward (only one is shown)
And an upper plate 3B on the upper and lower surfaces of the vertical plate 3A.
A lower plate 3C is provided. As a result, a space is formed between the upper plate 3B and the lower plate 3C, and a cylinder 14, which will be described later, is provided in this space.

Reference numeral 7 denotes an engine mounted on the revolving frame 3 located in the building cover 5. The engine 7 is an engine block 7A containing a piston (not shown) and the like.
And a drive shaft 7B and the like extending in the engine block 7A in the front and rear directions and projecting at the rear end. 4 and 5, a cylindrical coil housing space 7C in which an electromagnetic coil 30 described later is housed is formed on the rear side of the cylinder block 7A.

Reference numerals 8 denote a plurality of hydraulic pumps (only two are shown) mounted on the front side of the engine 7. Each of the hydraulic pumps 8 is driven by a drive shaft via a speed reducer (not shown). 7B. As a result, the hydraulic pump 8 is driven by the engine 7 and supplies pressure oil to hydraulic equipment provided in the lower traveling body 1, the working device, and the like.

Reference numeral 9 denotes a radiator as a heat exchanger disposed on the rear side of the engine 7. The radiator 9 is connected to a water jacket (neither is shown) of the engine 7 via a hose.

Reference numeral 10 denotes a cooling fan provided to face the radiator 9. The cooling fan 10 includes a hub member 11 forming a center of rotation and a plurality of cooling fans integrally mounted on the outer peripheral side of the hub member 11. (Only two are shown). And the cooling fan 10
The blades 12 supply cooling air to the radiator 9 by being rotationally driven by the engine 7.

Here, the hub member 11 is formed in a disk shape, and a rod insertion hole 11A through which the operation rod 31 is inserted is formed in the center of the shaft. Further, a plurality of engagement holes 11B, which are located on the outer peripheral side of the rod insertion hole 11A and are engaged with the engagement protrusion 27B of the connecting body 27 to be described later, are removably engaged with the proximal end surface of the hub member 11. , 11B (only two are shown). Further, a plurality of stopper holes 11 </ b> C with which stopper protrusions 31 </ b> D of the operation rod 31, which will be described later, engage, are formed on the distal end surface of the hub member 11.

Reference numeral 13 denotes a fire extinguisher provided on the upper swing body 2. The fire extinguisher 13 injects a fire extinguishing agent into the building cover 5 when the temperature inside the building cover 5 becomes abnormally high. As shown in FIGS. 1 and 2, the fire extinguisher 13 includes a cylinder 14, a hose 16,
7, a manual switch 18, a temperature sensor 19, and the like.

.., 14 are lower plates 3 of the revolving frame 3.
For example, three cylinders arranged on C, each cylinder 1
4 is filled with a fire extinguishing agent composed of powder, liquid, or the like. The cylinders 14 are connected to each other, and one of the three cylinders 14 is normally closed, and is provided with an electromagnetic opening / closing valve 15 that opens when power is supplied to allow the extinguishing agent to flow out. I have.

Reference numeral 16 denotes a hose having a base end connected to each cylinder 14 via an electromagnetic on-off valve 15 and a front end extending up to the inside of the building cover 5. The front end of the hose 16 branches off.
Injection nozzles 17, 17 for injecting a fire extinguishing agent toward the engine 7, the hydraulic pump 8 and the like are attached to the respective distal ends.

Reference numeral 18 denotes a manual switch provided in the cab 4. The manual switch 18 is manually operated by the operator when the operator visually detects that a fire has occurred in the building cover 5. Things.

Reference numeral 19 denotes a temperature sensor provided inside the building cover 5 above the engine 7.
When the temperature inside the building cover 5 becomes abnormally high, the temperature is sensed and a signal is transmitted.

Reference numeral 20 denotes an engine block 7A of the engine 7.
And a cooling fan 10 provided between the cooling fan 10 and the fan stopping device 20, as shown in FIGS.
It includes the hub member 11 of the cooling fan 10 described above, and is generally constituted by a rotation transmitting body 22, a clutch mechanism 26, a clutch operating mechanism 29, and the like, which will be described later.

A pedestal 21 is located on the rear side of the engine 7 and arranged coaxially with the coil housing space 7C.
The base end is bolted to the rear end face of the engine block 7A, and the front end is expanded to form a disc shape, and is formed in a round table shape as a whole. A rod insertion hole 21 </ b> A through which the operation rod 31 is inserted is formed in the axis of the pedestal 21.

Reference numeral 22 denotes a rotation transmission member which is coaxial with the hub member 11 of the cooling fan 10 and is rotatably mounted on the pedestal 21 via a bearing 23. The rotation transmission member 22 is formed in a disk shape and has a shaft. Concave part 2 opening toward the tip at the center
2A is formed. The rotation transmitting body 22 is formed with a plurality of fitting holes 22B which are located on the bottom surface of the concave portion 22A and in which fitting protrusions 27A of a connecting body 27 described later are slidably fitted. Further, the hub member 11 of the cooling fan 10 is rotatably attached to the rotation transmitting body 22 via a bearing 24. The rotation transmitting body 22 is driven by a drive shaft 7B of the engine 7 via a plurality of belts 25, 25,.
It is connected to the.

Reference numeral 26 denotes a clutch mechanism provided between the rotation transmitting body 22 and the hub member 11 of the cooling fan 10. The clutch mechanism 26 can fasten and detach the rotation transmitting body 22 and the hub member 11 from each other. And a connecting member 27 which is disposed between the connecting member 27 and the rotation transmitting member 22 and is connected to the connecting member 27.
Spring 2 for urging the spring in the direction of arrow A, which is the fastening side
8 and is roughly constituted.

Here, the connecting body 27 is formed as an annular plate body, and has a plurality of fitting projections 27A, slidably fitted in the respective fitting holes 22B of the rotation transmitting body 22 on one end surface. 2
7A is protruded, and a plurality of engaging projections 2 are provided on the other end surface so as to engage with and detach from the respective engaging holes 11B of the hub member 11.
7B and 27B (in each case, only two are shown) protrude.

The clutch mechanism 26 normally engages the engagement protrusion 27B of the connecting member 27 with the engagement hole 11B of the hub member 11 by the coil spring 28, thereby connecting the rotation transmitting member 22 and the hub member 11 to each other. Between the two. On the other hand, when the coupling body 27 is moved in the direction of arrow B by the clutch operating mechanism 29 described later, the engagement protrusion 27B of the coupling body 27
Is disengaged from the engagement hole 11B of the hub member 11, and the connection between the rotation transmitting body 22 and the hub member 11 is released.

Reference numeral 29 denotes a clutch operating mechanism for operating the coupling body 27 of the clutch mechanism 26 to release the engagement of the clutch mechanism 26. The clutch operating mechanism 29 is generally constituted by an electromagnetic coil 30, an operating rod 31, and the like, which will be described later. ing.

Reference numeral 30 denotes an electromagnetic coil which forms an electromagnetic actuator accommodated in the coil accommodating space 7C of the engine 7. The electromagnetic coil 30 is energized by being supplied with power and displaces the operating rod 31 in the direction of arrow B. It is.

Reference numeral 31 denotes the engine block 7A and the hub member 1
The operation rod 31 is made of a magnetic material. The operation rod 31 is inserted into the electromagnetic coil 30 at the base end, and is inserted into the rod insertion hole 11A of the hub member 11 at the base end. A penetrated rod portion 31A, and a disk portion 31 provided with an enlarged diameter at the tip of the rod portion 31A
And B. Also, the operating rod 3
1 includes a connecting member 27 located on the distal end side of the rod portion 31A.
And a stopper portion 11C of the hub member 11 which protrudes from an end surface of the disc portion 31B.
Stopper projections 3 that form an inertial rotation stop that engages with
1D and 31D (only two are shown).

Reference numeral 32 denotes a detent lever which is located in the coil accommodating space 7C of the engine 7 and is attached to the rod portion 31A of the operation rod 31. The detent lever 32 extends parallel to the operation rod 31 and has an end portion. Is the engine block 7A
Is slidably engaged with the detent pin 33 fitted to the pin. Thereby, the detent lever 32 and the detent pin 3
Reference numeral 3 restricts rotation of the operation rod 31 while allowing the operation rod 31 to be displaced in the axial direction.

Reference numeral 34 denotes a coil spring disposed between the bottom surface of the coil accommodating space 7C of the engine 7 and the end surface of the rod portion 31A of the operation rod 31. The coil spring 34 constantly moves the operation rod 31 in the direction of arrow A. It is energizing.

Here, the electromagnetic on-off valve 15, the electromagnetic coil 30
Referring to FIG. 3, a manual switch 1 is connected between the power terminals 35A and 35B.
8. Parallel circuit of temperature sensor 19 and coil 3 of relay 36
6A is connected to the series circuit, and the solenoid on-off valve 1
5. A series circuit of the parallel circuit of the electromagnetic coil 30 and the normally open contact 36B of the relay 36 is connected.

Thus, when one of the manual switch 18 and the temperature sensor 19 is closed, the coil 36A of the relay 36 is excited, the contact 36B is closed, and the electromagnetic switching valve 15 and the electromagnetic coil 30 are connected. It is configured to operate.

The fan stopping device 20 configured as described above
In the normal operation state, the clutch actuating mechanism 29, as shown in FIG.
4, the operation rod 31 is urged in the direction of arrow A, and the stopper projection 31D of the operation rod 31 is separated from the stopper hole 11C of the hub member 11. Also, the connecting body 27
Is urged in the direction of arrow A by the coil spring 28, and the engagement protrusion 27B is engaged with the engagement hole 11B of the hub member 11. Thus, when the rotation transmitting body 22 is rotationally driven by the drive shaft 7B of the engine 7, the cooling fan 10 rotates via the connecting body 27, and the cooling fan 10 supplies cooling air to the radiator 9.

On the other hand, when power is supplied to the electromagnetic coil 30 of the clutch operating mechanism 29, the operating rod 31 is displaced in the direction of arrow B against the coil spring 34 as shown in FIG. As a result, the connecting body 27 is pushed in the direction of arrow B by the flange 31C of the operating rod 31 against the coil spring 28, so that the engagement projection 27B of the connecting body 27
The rotation transmission body 22 and the cooling fan 10 are disengaged from the first engagement hole 11B. At this time, a stopper projection 31D provided on the operation rod 31 is provided with a stopper hole 11C provided on the hub member 11 of the cooling fan 10.
Therefore, the cooling fan 10 rotating by inertia can be forcibly stopped.

The hydraulic shovel according to the present embodiment has the above-described configuration. Next, the operation of the hydraulic shovel will be described.

First, each hydraulic pump 8 is operated by the engine 7.
, The hydraulic oil is supplied from each of the hydraulic pumps 8 to the lower traveling body 1 to cause the lower traveling body 1 to travel. Also, pressurized oil is supplied to the working device, and excavation work of earth and sand is performed by the working device.

When the engine 7 is driven, the cooling fan 10 connected to the drive shaft 7B of the engine 7 via the fan stop device 20 is driven to rotate and the cooling air is supplied to the radiator 9, so that the engine 7 is driven. 7 can be cooled.

Next, a case where a fire occurs in the building cover 5 and the inside of the building cover 5 becomes abnormally high will be described. In this case, the switch 36 is closed by operating the manual switch 18 or closed by the temperature sensor 19 detecting an abnormally high temperature, so that the coil 36A of the relay 36 is excited and the contact 36B is closed, and the cylinder is closed. Both the electromagnetic on / off valve 14 of 14 and the electromagnetic coil 30 of the fan stopping device 20 operate.

As a result, the electromagnetic on-off valve 15 is opened, and the fire extinguishing agent in the cylinder 14 is discharged from the injection nozzle 1 through the hose 16.
From 7, it is injected into the building cover 5. Simultaneously with this operation, the fan stop device 20 forcibly stops the rotation of the cooling fan 10, so that the flow of the cooling air can be stopped. As a result, the fire extinguishing agent can be properly injected into a desired range without being blown off by the cooling air.

Thus, according to the present embodiment, when the temperature inside the building cover 5 becomes abnormally high, the cooling fan 10 is rotated by the fan stopping device 20 almost simultaneously with the injection of the fire extinguishing agent by the fire extinguishing device 13. Since it can be stopped and the cooling air from the cooling fan 10 can be stopped, the fire extinguishing agent can be immediately injected into a desired range, and the initial fire extinguishing can be performed at a stage where the range of the fire is small. As a result, the fire can be extinguished in a short time and the amount of the fire extinguisher used can be reduced, so that the fire extinguishing efficiency can be improved and the reliability can be improved.

When the cooling fan 10 is forcibly stopped, the clutch operating mechanism 29 releases the engagement between the rotation transmitting body 22 and the cooling fan 10 by the clutch mechanism 26. The cooling fan 10 can be stopped without giving it, and damage to the engine 7 and the like can be prevented.

In the embodiment, the radiator 9 for cooling the cooling water of the engine 7 has been described as an example of the heat exchanger. However, the present invention is not limited to this, and an oil cooler for cooling hydraulic oil, an air cooler, and the like. The present invention may be applied to a heat exchanger such as a condenser of a harmony device, or may be applied to an arrangement in which these heat exchangers are arranged in an overlapping manner.

Further, in the embodiment, the case where the manual switch 18 is provided in the cab 4 has been described as an example. However, the present invention is not limited to this, and the position that can be operated from outside the excavator is described. Alternatively, a manual switch may be provided in the device.

Further, in the embodiment, the hydraulic shovel has been described as an example of a construction machine. However, the present invention is not limited to this, and may be applied to other construction machines such as a hydraulic crane and a bulldozer. Alternatively, the present invention may be applied to a wheel type excavator.

[0059]

As described in detail above, according to the first aspect of the present invention, a fan stop device for forcibly stopping the rotation of the cooling fan almost simultaneously with the fire extinguishing device injecting the fire extinguishing agent is provided. Therefore, when the inside of the building cover becomes extremely hot, the fan stop device can forcibly stop the rotation of the cooling fan at almost the same time as the fire extinguisher injects the fire extinguishing agent. Flow can be stopped.

As a result, the fire extinguishing agent can be immediately injected into a desired range, and the initial fire extinguishing can be performed at a stage where the range of the fire is small. It can reduce the fire extinguishing efficiency and increase the reliability.

According to the second aspect of the present invention, the fan stopping device is provided coaxially with the hub member of the cooling fan, and transmits a rotation of the engine to the cooling fan. A clutch mechanism for fastening and releasably connecting with the hub member, and a clutch operating mechanism which is actuated by an external signal when the inside of the building cover becomes abnormally high temperature and releases the fastening of the clutch mechanism. are doing. Therefore, when the clutch operating mechanism is operated by an external signal, the fan stop device can release the engagement of the clutch mechanism and stop the rotation of the cooling fan regardless of the operating state of the engine. Thus, the rotation of the cooling fan can be stopped immediately without imposing a load on the engine.

According to the third aspect of the present invention, since the clutch operating mechanism is constituted by the electromagnetic actuator and the operating member which is operated by the electromagnetic actuator to release the engagement of the clutch mechanism, power is supplied to the electromagnetic actuator. By operating the operation member, the engagement of the clutch mechanism can be released by the operation member.

According to the fourth aspect of the present invention, the operating member includes
Since the inertia rotation stop part which engages with the hub member of the cooling fan and stops the inertia rotation of the cooling fan is provided, the inertia rotation stop part engages with the hub member of the cooling fan, thereby causing the inertia rotation of the cooling fan. Can be forcibly stopped, and a fire extinguishing operation can be performed at an early stage.

According to the fifth aspect of the present invention, the clutch operating mechanism is operated by a manual switch operated by an operator or a signal from a temperature sensor provided in the building cover and detecting the temperature in the building cover. Therefore, the clutch operation mechanism can be operated by a signal transmitted from a manual switch or a temperature sensor provided in the building cover, the fan stop device is operated in synchronization with the fire extinguishing device, and the fire extinguishing agent is efficiently injected. can do.

[Brief description of the drawings]

FIG. 1 is a partially broken front view showing a hydraulic excavator applied to an embodiment of the present invention.

FIG. 2 is an enlarged front view of a partly broken view showing an enlarged structure inside a building cover in FIG. 1;

FIG. 3 is a circuit diagram for operating an electromagnetic on-off valve and an electromagnetic coil.

FIG. 4 is an enlarged sectional view showing a main part of the fan stopping device in FIG. 1 in a normal operation state.

FIG. 5 is an enlarged cross-sectional view of a main part of the fan stop device when the cooling fan is forcibly stopped, as viewed from the same position as in FIG. 4;

[Explanation of symbols]

 Reference Signs List 3 Revolving frame 5 Building cover 7 Engine 9 Radiator (heat exchanger) 10 Cooling fan 11 Hub member 13 Fire extinguisher 18 Manual switch 19 Temperature sensor 20 Fan stopping device 22 Rotation transmitting body 26 Clutch mechanism 29 Clutch operating mechanism 30 Electromagnetic coil (electromagnetic) Actuator) 31 Operation rod (operation member) 31D Stopper projection (coasting stop)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F01P 7/08 F01P 7/08 C

Claims (5)

[Claims] 1. A frame, a building cover provided on the frame, an engine located in the building cover and mounted on the frame, and a heat exchanger provided in the building cover. A construction machine comprising: a cooling fan driven by the engine to supply cooling air to the heat exchanger; and a fire extinguisher that injects a fire extinguishing agent into the building cover when the inside of the building cover becomes abnormally high. 3. The construction machine according to claim 1, further comprising a fan stop device for forcibly stopping the rotation of the cooling fan substantially simultaneously with the fire extinguishing device injecting the fire extinguishing agent. 2. The cooling device according to claim 1, wherein the fan stopping device is provided coaxially with a hub member of the cooling fan, and transmits a rotation of the engine to the cooling fan. A clutch mechanism for releasably connecting and disconnecting the clutches, and a clutch operating mechanism that is activated by an external signal when the inside of the building cover becomes abnormally high temperature and releases the fastening of the clutch mechanism. The construction machine according to claim 1. 3. The construction machine according to claim 2, wherein the clutch operating mechanism includes an electromagnetic actuator and an operation member that is operated by the electromagnetic actuator to release the engagement of the clutch mechanism. 4. The construction machine according to claim 3, wherein the operation member is provided with an inertia rotation stop portion that engages with a hub member of the cooling fan to stop the inertia rotation of the cooling fan. 5. The clutch operating mechanism according to claim 2, wherein said clutch operating mechanism is operated by a signal from a manual switch operated by an operator or a temperature sensor provided in said building cover and detecting a temperature inside said building cover.
The construction machine according to 3 or 4.