JP2005207065A - Safety device for construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safety device for a construction machine capable of ensuring safety during the tilt-up operation of a driver's cab and performing the operation of a front working machine if necessary after the tilt-up of the driver's cab. <P>SOLUTION: This safety device 44 is provided with a solenoid valve 37 provided on a hydraulic line 45 between a pilot pump 32 and pressure reducing valves 38A, 38B to communicate or shut off the hydraulic line 45; a battery 39 which is a power supply of the solenoid valve 37; a fuse 41 provided in series between the solenoid valve 37 and the battery 39 for overcurrent protection; and a gate lock switch 33 operated by a gate lock lever 28 and switching current application from the battery 39 to the solenoid valve 37 to switch the solenoid valve 37. The switch 23 is connected in series between the solenoid valve 37 and the battery 39. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a safety device for a construction machine such as a hydraulic excavator having a structure that supports a driver's cab so that the driver's cab can be tilted forward with respect to a revolving frame and allows the cab to be tilted up.

  In general, a construction machine such as a hydraulic excavator includes a traveling body, a revolving body, and a front work machine, and the revolving body includes a revolving frame and a cab, and the operation base operates the front work machine and the revolving body. The device and the driver's seat are arranged. In such a construction machine, for example, as described in Japanese Patent Application Laid-Open No. 2001-39352, a cab is supported so as to be tiltable forward with respect to the turning frame, and the cab can be tilted up. It has been known. By tilting up the driver's cab in this way, components hidden on the bottom side of the normal driver's cab floor, equipment / electrical (electronic) components and wiring housed in the swivel frame body below the driver's cab There is an advantage that maintenance such as the above becomes easy.

  On the other hand, the operating device provided in the cab operates the control lever by operating the operating lever and outputting the secondary pilot pressure from the pressure reducing valve based on the pilot primary pressure of the pilot pump to drive the hydraulic actuator. Thus, the traveling body, the revolving body, and the front work machine are operated. A gate lock lever device is disclosed in, for example, Japanese Patent No. 2567720, which permits or disables pilot operation of a control valve by such an operation device. This is because a gate lock lever is provided in the getting-on / off passage of the cab, and when the worker gets off the cab, when the gate lock lever is raised upward, the passage between the pilot pump and the pressure reducing valve is cut off, The primary pressure (pilot primary pressure) is cut off, and the pilot operation of the control valve is disabled (thus, the actuator cannot be driven), which makes it safer against accidental lever operation when the operator gets down. Can be secured.

JP 2001-39352 A Japanese Patent No. 2567720

  In construction machines equipped with a structure that allows the cab to be tilted up with respect to the swivel frame, service personnel who perform maintenance of the machine check the operation of the hydraulic equipment, etc. on the bottom side of the cab floor and the swivel frame. Front work with the cab tilted up to check the status of repairs or to check the operation of electrical components, for example, the operation of the alternator mounted on the engine or the operation of the excavator controller You may want to operate the machine. In this case, up to now, the gate lock lever has been lowered and the control valve has been allowed to be piloted for tilting up. However, when tilting up with the pilot operation of the control valve in this way, a tool or the like suddenly collides with the operating lever of the operating device on the cab during the tilting up operation, causing the front work machine to suddenly operate. There was a possibility. In addition, when the control lever itself is not operated, the control lever is in the neutral state, but the control lever cannot maintain the neutral state due to a failure of the support portion of the control lever, for example, a spring that holds the control lever in the neutral position There is. At this time, there is a possibility that the operation lever is tilted by the tilt-up operation and the front work machine suddenly operates.

  A first object of the present invention is to provide a construction machine safety device capable of ensuring safety during a tilt-up operation of a cab in a construction machine having a structure that allows the cab to be tilted up. It is.

  The second object of the present invention is to secure safety during the tilt-up operation of the cab in the construction machine having a structure that allows the cab to be tilted up. To provide a safety device for a construction machine that enables operation of a front work machine as required.

  (1) In order to achieve the first object, the present invention includes a traveling body, a turning body, and a front working machine, and the turning body includes a turning frame and a cab, and the front working machine and the turning machine are provided. An operating lever for operating the body and a driver's seat are arranged on the driver's cab, and the driver's cab is tiltably supported forward with respect to the turning frame, and the construction machine having a structure that allows the driver's cab to be tilted up is provided. In the safety device, it is assumed that an operation restricting means for prohibiting the operation of the front work machine when the cab is tilted up is provided.

  In this way, by providing operation restriction means and prohibiting the operation of the front work machine when the cab is tilted up, tools etc. are unexpectedly moved to the operating lever of the operating device on the cab during the tilt up operation. Even if the operation lever tilts due to a collision or failure of the support portion of the operation lever, the front working machine is prevented from operating suddenly, and safety during the tilt-up operation of the cab can be ensured.

  (2) Further, in order to achieve the second object, the present invention provides a safety device for a construction machine according to (1), wherein the operation restricting means is manually operated in a state where the cab is tilted up. It is further provided with prohibition canceling means for canceling the prohibition state of the operation of the front work machine.

  As a result, the front work machine can be operated as needed after tilting up. If you want to operate the front work machine with the cab tilted up to check the operation of hydraulic equipment, etc. Can be operated easily.

  (3) In the above (1), preferably, the construction machine includes a main hydraulic pump, and a plurality of hydraulic actuators that are driven by pressure oil discharged from the hydraulic pump to drive the front working machine and the swing body. Pilot operated by a plurality of control valves for controlling the flow of pressure oil supplied from the main hydraulic pump to the plurality of hydraulic actuators, a pilot pump, and the operation lever, and using a pilot pump discharge pressure as a pilot primary pressure. An operation lever device that generates a secondary pressure and switches the pilot operated control valve, and the operation restricting means is provided in a pilot primary pressure line that guides the pilot primary pressure from the pilot pump to the operation lever device. A solenoid valve for switching communication / shutoff of the pilot primary pressure line; Cab and a switching control means for switching the shut-off position the solenoid valve when it is tilted up from the communicating position.

  As a result, when the cab is tilted up, the pilot primary pressure line is cut off, so that the operation lever device becomes inoperable and the operation of the front work machine can be prohibited.

  (4) In the above (3), preferably, the construction machine further includes a gate lock lever disposed in the cab, and the electromagnetic valve is an electromagnetic valve that is switched by the gate lock lever.

  As a result, the operation restricting means can be configured using an electromagnetic valve that is switched by the gate lock lever, the total number of parts can be reduced, and the operation restricting means can be configured to be simple and inexpensive.

  (5) In the above (1), preferably, the construction machine includes a main hydraulic pump, a plurality of hydraulic actuators driven by pressure oil discharged from the hydraulic pump to drive the front working machine, An engine that drives a main hydraulic pump, and the operation restricting means is a fuel supply stopping means for stopping the supply of fuel to the engine when the cab is tilted up.

  As a result, when the cab is tilted up, the engine is stopped, so that the driving of the main hydraulic pump is also stopped and the operation of the front work machine can be prohibited.

  Conventionally, when the cab is tilted up while the engine is running, the engine cooling fan is rotating at a high speed, and the hydraulic main hydraulic pump and hose pressurized to high pressure are Since it was exposed, the service staff could come in contact with the rotating engine cooling fan and the high-pressure hose, and it was necessary to work with caution. When the cab is tilted up, the supply of fuel to the engine is stopped and the engine is stopped, so that the rotation of the engine cooling fan stops and the drive of the main hydraulic pump is also stopped, and the hydraulic pressure becomes the tank pressure. Therefore, there is no danger even if the service person contacts the engine cooling fan or the hose, and the safety during the tilt-up operation of the cab is further improved.

  (6) In the above (1), preferably, the operation restricting means operates when a current is supplied from the power source, and the electromagnetic switching means for disabling the front work machine, Switch means capable of interrupting the supply of current from the power source to the electromagnetic switching means, the switch means having a first position that is closed when the cab is tilted down, and the cab is tilted up And a third position that is closed by manual operation and maintains this state when in the second position.

  As a result, since the switch means can be configured using a single switch, the operation restricting means can be configured to be simple and inexpensive.

  (7) In the above (1), preferably, the operation restricting means operates when a current is supplied from the power source, and the electromagnetic switching means that disables the front work machine, Switch means capable of interrupting the supply of current from the power source to the electromagnetic switching means. The switch means includes first and second switches connected in series, and in parallel with the first and second switches. The first and second switches are closed when the cab is tilted down, the first switch is closed, the second switch is open, and the cab is tilted up when the cab is tilted up. The first switch is closed and the second switch is open. The relay is turned on when the first switch is closed, and once the switch is turned on while the second switch is closed, the relay then forwards. The first switch and the second switch are in the order of the first switch and the second switch when the cab tilts up. When the cab tilts down, the first switch and the second switch are arranged in this order.

As a result, it is possible to configure the switch means by using a momentary operation switch that is easily available, and it is possible to make the operation regulating means inexpensive.

  According to the present invention, even if a tool or the like suddenly collides with the operating lever of the operating device on the cab during the tilt-up operation, or the operating lever tilts due to a failure of the operating lever support, the front work machine suddenly The operation is prevented, and the safety during the tilt-up operation of the cab can be ensured.

  In addition, according to the present invention, the front work machine can be operated as necessary after tilting up, so that the front work machine can be operated with the cab tilted up to check the operation of hydraulic equipment and the like. If desired, the front work machine can be operated easily.

Further, according to the present invention, when the cab is tilted up, the engine stops, the engine cooling fan stops rotating, and the main hydraulic pump stops driving, so that the hydraulic pressure becomes the tank pressure. There is no danger even if it comes into contact with the engine cooling fan or the hose, and the safety during the tilt-up operation of the cab is further improved.

  Embodiments of the present invention will be described below with reference to the drawings.

  A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a side view showing the overall structure of a small hydraulic excavator to which the safety device for a construction machine according to this embodiment is applied. In the following description, the front side (right side in FIG. 1), rear side (left side in FIG. 1), right side (FIG. 1) of the worker when the operator is seated on the driver's seat in the state shown in FIG. The front side of 1 paper side and the left side (back side of the paper surface in FIG. 1) are simply referred to as front side, back side, right side, and left side.

  In FIG. 1, the hydraulic excavator includes a lower traveling body 1 having traveling means, an upper revolving body 2 that is turnably mounted on an upper portion of the lower traveling body 1, and a front work machine 3. The lower traveling body 1 is a right / left traveling hydraulic motor for driving driving wheels 10R and 10L (only 10R is shown in FIG. 1) rotatably supported near the rear ends of both right and left sides of the track frame 9. 11R and 11L (however, only 11R is shown in FIG. 1), and a blade 14 for soil removal that moves up and down by a hydraulic cylinder 13 for blades is provided on the front side of the track frame 9.

  The upper swing body 2 includes a swing frame 4 that forms a basic lower structure, a swing post 5 that is pivotally attached to the tip of the swing frame 4 around a vertical pin (not shown), and a swing frame. 4 includes a so-called cabin type cab 7 and an exterior cover 8 that covers most of the swivel frame 4 other than the cab 7. The swing post 5 is connected to a swing hydraulic cylinder 16 provided on the revolving frame 4 via a connection pin (not shown), and the swing post 5 extends and contracts in the vertical direction by expansion and contraction of the swing hydraulic cylinder 16. By rotating around the axis, the front work machine 3 swings to the right and left. The front work machine 3 includes a boom 17, an arm 18 that is rotatably connected to the boom 17, and a bucket 19 that is rotatably connected to the arm 18. The boom 17, the arm 18, and the bucket 19 are operated by a boom hydraulic cylinder 20, an arm hydraulic cylinder 21, and a bucket hydraulic cylinder 22, respectively. Inside the exterior cover 8 are an engine 34 (see FIG. 8 to be described later), a main hydraulic pump 35 (see FIG. 8 to be described later) driven by the engine 34, a pilot pump 32, and a fuel tank for storing fuel of the engine 34. 42 (see FIG. 13 to be described later), equipment such as a hydraulic oil tank (not shown) serving as a pressure oil source of the hydraulic pump is accommodated.

  FIG. 2 is a side view showing the inside of the cab 7 of the small hydraulic excavator shown in FIG. A driver's seat 25 on which a worker sits is provided in the operator's cab 7, and a bucket / boom manual operation lever 26R and a swivel / arm manual operation lever 26L (see FIG. 8) are provided on the right and left sides of the driver's seat 25. ) Are provided in front of the driver's seat 25, and right / left travel operation levers 29R and 29L (only 29L is shown in FIG. 2) are provided. On the right side of the driver's seat 25, a blade manual operation lever 27 for driving the blade hydraulic cylinder 13 and moving the blade 14 up and down is provided. A gate lock lever 28 is provided on the left side of the driver seat 25. The gate lock lever 28 opens and closes an operator's boarding / alighting passage and enables or disables the hydraulic pilot system in accordance with the opening / closing operation.

  The above-described small hydraulic excavator is provided with a tilt-up mechanism for enabling the cab 7 to be tilted up. FIG. 3 is an external perspective view showing a state where the small hydraulic excavator shown in FIG. 1 is tilted up from the right front side. In this figure, a part of the outer cover 8 of the upper swing body 2, the engine 34, the tank and the like are removed, and reference numeral 60 indicates a tilting mechanism which is a main part of a tilt-up structure for tilting up the cab 7. . Hereinafter, this tilt-up structure will be described with reference to FIGS.

  FIG. 4 is a side view showing a main part of the upper-part turning body 2 in a state where the outer cover 8, the engine 34, the tank and the like of the small hydraulic excavator are removed. FIG. 5 is a view showing a state in which the cover or the like is removed as in FIG. 4 and the cab 7 is tilted up.

  3 to 5, the revolving frame 4 has a bottom plate 56, a pair of vertical plates 57 erected on the bottom plate 56, a front beam 58 extending in the left-right direction on the front side of the vertical plate 57, and a rear portion of the bottom plate 56. And a support member 51 located at the same position. The cab 7 includes a floor board 50 and a cab 15 provided on the floor board 50 so as to cover the periphery of the driver seat 25. The floor plate 50 of the cab 7 is attached to the front beam 58 of the swivel frame 4 via the floor plate support mechanism 53 so that the front portion thereof can be tilted. A support base 59 is provided at the upper rear end portion of the support member 51, and a cab mounting plate 52 is provided at the lower rear end portion of the cab 15. The cab mounting plate 52 has a shape extending in the left-right direction, and is connected to the support base 59 by a bolt. By removing this bolt, the floor plate 50 can be tilted up.

  The tilt mechanism 60 is provided between the support member 51 on the revolving frame 4 and the side plate 54 provided in the cab 7. FIG. 6 is an external perspective view showing the tilting mechanism 60 in an enlarged manner.

  The tilting mechanism 60 has a mounting bracket 61, a guide rail 63, a screw shaft 64, and a moving member 65. The base end of the guide rail 63 is attached to the mounting bracket 61 by a connecting pin 62 so as to be vertically rotatable. The bracket 61 is bolted to the support member 51 on the revolving frame 4 side. The guide rail 63 is for guiding the moving member 65 linearly between the base end side (mounting bracket side) and the free end side. The screw shaft 64 is a rod-like body having a thread cut on the outer periphery, is provided between the rails of the guide rail 63, and is screwed into a screw hole 67 formed in the moving member 65. A distal end connecting plate 68 is provided on the free end side of the guide rail 63, and a screw shaft 64 is rotatably supported by the distal end connecting plate 68 via a thrust bearing. The other end of the screw shaft 64 is a free end. The moving member 65 is disposed so as to be movable between the rails of the guide rail 63, and the other end is inserted into a sleeve 55 attached to the side plate 54, and in this state, is screwed by a bolt 66 and is prevented from being pulled out. A hexagonal tool connecting portion 69 is provided on the tip end side of the screw shaft 64 and is fixed to the screw shaft 64. The tool connecting portion 69 can connect a screw tightening tool such as an impact wrench for fastening a bolt from the outside. Thereby, the screw shaft 64 can be rotationally driven by the impact wrench, and the screwed moving member 65 can be moved along the guide rail 63.

  3 to 6, when the cab 7 is tilted up, the bolts to which the support member 51 and the cabin mounting plate 52 are attached are removed, and the screw shaft 64 of the tilting mechanism 60 is located on the tip side of the screw shaft 64. An impact wrench or the like is connected to the square tool connecting portion 69, and the screw shaft 64 is rotationally driven. As a result, the moving member 65 moves along the guide rail 63 in the direction of arrow C shown in FIGS. 3 to 6, and the tilting mechanism 60 rotates upward about the connecting pin 62, and at the same time, the moving member 65. The driver's cab 7 including the side plate 54, the floor plate 50, and the like to which can be attached can be tilted up from the floor plate support mechanism 53 toward the upper side or the front side indicated by the arrow A direction in FIGS. Become.

  In this manner, with the cab 7 tilted up, the service staff can perform maintenance operations such as inspection, maintenance, and repair. After various operations are finished, the screw member 64 is driven to rotate in the reverse direction with an impact wrench, so that the moving member 65 moves in the direction of arrow D shown in FIGS. A cab 7 that rotates downward about 62 and includes a side plate 54 and a floor plate 50 to which a moving member 65 is attached at the same time is shown as an arrow B direction in FIGS. It is possible to tilt down in the downward direction. Then, the maintenance work can be completed by fastening the cabin mounting plate 52 with the support member 51 bolts.

  When service personnel perform maintenance work such as inspection, maintenance, repair, etc. with the cab 7 tilted up as described above, check the operation of hydraulic equipment, electrical equipment, engine 34, alternator, excavator control controller, etc. For this reason, there is a case where it is desired to operate the work implement while the cab 7 is kept in the tilted up state. Until now, the cab 7 was tilted up with the gate lock lever 28 lowered and the pilot operation permitted, but the tool in the cab 7 was unexpectedly moved during the tilt-up operation and in the tilt-up state. There is a danger that the operating lever tilts and the working machine suddenly starts to move due to a collision of the operating lever or the like, or a malfunction of the neutral maintaining mechanism of the operating lever. The hydraulic excavator of the present invention includes a safety device that ensures safety in such a case. The safety device will be described below.

  3 to 5, the safety device has a switch 23 provided on a vertical plate 57 on the revolving frame 4. An enlarged view of the switch 23 is shown in FIG. In FIG. 7, the switch 23 has a switch body 70 and a button 71, and the switch body 70 is mounted on a vertical plate 57 on the revolving frame 4 by a bracket 72, and the button 71 is provided on the upper part of the switch body 70. . The button 71 can be switched to three positions A, B, and C. At the position A, the switch 23 is OFF (open), and at the positions B and C, the switch 23 is ON (closed). The positions A and B are momentary operation switches at the normal A position (OFF), and the position C is a position when the button 71 is pulled up manually, and after the button 71 is once switched to the position C. The position is maintained. Therefore, the button 71 is at the position B (ON) when the cab 7 is tilted down, and when the cab 7 is tilted up, the button 71 is switched from the position B (ON) to the position A (OFF). Further, when the operator's cab 7 is tilted up and the button 71 is manually pulled up, the position C (ON) is obtained, and the position C is held even if the hand is released thereafter. When the button 71 is manually pressed thereafter, the button 71 is switched to the position A (OFF).

It is a figure which shows the hydraulic drive device of the small hydraulic excavator provided with the safety device of the construction machine of this invention of FIG.
In FIG. 8, the hydraulic drive device includes the engine 34, the main hydraulic pump 35, and the hydraulic cylinder 80 described above. The hydraulic cylinder 80 is representative of various actuators such as a boom hydraulic cylinder 20, an arm hydraulic cylinder 21, a bucket hydraulic cylinder 22, a swing hydraulic cylinder 16, a blade hydraulic cylinder 13, and the like. The hydraulic cylinder 80 is driven by the engine 34 (the prime mover), and the hydraulic cylinder 80 is driven by the pressure oil discharged from the hydraulic pump 35. The hydraulic drive device includes a hydraulic pilot control valve 36 that controls the flow rate of the pressure oil supplied from the hydraulic pump 35 to the hydraulic cylinder 80, an operation lever device 31 that instructs the operation of the hydraulic device, and a pilot pump 32. It has.

  The operation lever device 31 includes an operation lever 81 and a pair of pressure reducing valves 38A and 38B that output an operation pilot pressure obtained by reducing the primary pilot pressure from the pilot pump 32 in accordance with the operation amount of the operation lever 81. . The operation lever 81 is representative of various levers such as the bucket / boom manual operation lever 26R, the swing / arm manual operation lever 26L, and the blade manual operation lever 27 shown in FIG. The operation pilot pressure (secondary pilot pressure) is output from the pressure reducing valve 38A or 38B according to the operation direction and the displacement amount (operation amount), and this operation pilot pressure is guided to the pilot operation section 36a or 36b of the control valve 36. . As a result, the control valve 36 is switched, pressure oil from the hydraulic pump 35 is guided to the hydraulic cylinder 80, and the hydraulic cylinder 80 is driven.

  In FIG. 8, reference numeral 44 denotes a safety device according to the present embodiment. The safety device 44 is provided on a hydraulic line 45 between the pilot pump 32 and the pressure reducing valves 38 </ b> A and 38 </ b> B. A solenoid valve 37 that communicates and shuts off, a battery 39 that is a power source of the solenoid valve 37, a fuse 41 provided in series between the solenoid valve 37 and the battery 39 for overcurrent protection, and the gate lock lever And a gate lock switch 33 for switching the solenoid valve 37 by switching the energization from the battery 39 to the solenoid valve 37, and the switch 23 is connected in series between the solenoid valve 37 and the battery 39. Yes.

  In the above, the electromagnetic valve 37 and the switch 23 constitute an operation restricting means for prohibiting the operation of the front work machine 3 when the cab 7 as a cab is tilted up, and the electromagnetic valve 37 and the switch 23 are operated. In a state where the chamber 7 is tilted up, a manual release operation, that is, a prohibition canceling means for canceling the prohibition state of the operation of the front work machine 3 by the motion restricting means by manually lifting the button 71 of the switch 23 to the position C (ON) Configure.

  The switch 23 constitutes switching control means for switching the solenoid valve 37 from the communication position to the shut-off position when the cab 7 is tilted up. When the solenoid valve 37 is supplied with a current from a battery 39 as a power source. The electromagnetic switching means that operates and makes the front work machine 3 inoperable is constituted, and the switch 23 constitutes a switching means that can cut off the supply of current from the battery 39 to the electromagnetic switching means.

  Next, the operation of the safety device 44 including the switch 23 will be described.

  During work operation, the engine 34 is in an operating state and the cab 7 is tilted down. The gate lock lever 28 is in the lowered position (unlock position), and the contact 33a of the gate lock switch 33 is closed. In the state where the cab 7 is tilted down, the button 71 of the switch 23 is pushed by the floor board 50 to the position B, and the switch 23 is ON. Therefore, in such a state, the battery 39 energizes the solenoid 37a of the electromagnetic valve 37 via the switch 23, and the electromagnetic valve 37 is switched to the communication position 37R shown on the right side in FIG. As a result, the primary pilot pressure from the pilot pump 32 is guided to the pressure reducing valves 38A and 38B, the operation lever device 31 becomes operable, and the operation pilot pressure is output by the operation of the operation lever 81 to drive the hydraulic cylinder 80. can do.

  When the work is completed, the worker turns off the engine, raises the gate lock lever 28, and gets off the driver's seat. When the gate lock lever 28 is raised, the contact 33a of the gate lock switch 33 is opened, the power supply to the solenoid 37a is cut off, and the electromagnetic valve 37 is switched to the cut-off position 37L. As a result, transmission of the primary pilot pressure from the pilot pump 32 is cut off, and the operation lever device 31 becomes inoperable. In this state, even if the operation lever 81 is operated, the operation pilot pressure is not output, and the hydraulic cylinder 80 cannot be driven. As a result, transmission of the primary pilot pressure from the pilot pump 32 is cut off, and the operation lever device 31 becomes inoperable. In this state, even if the operation lever 81 is operated, the operation pilot pressure is not output and the hydraulic cylinder 80 cannot be driven.

  Service personnel who perform maintenance of the hydraulic excavator check the operation and repair status of hydraulic equipment etc. on the bottom side of the cab floor and the swivel frame, or check the operation of electrical equipment, for example, installed in the engine In order to perform an operation check of an alternator and an operation check of an excavator control controller (hereinafter referred to as maintenance / inspection), it may be desired to tilt up the cab 7 and operate the front work machine in that state. In this case, the service person activates the engine 34 and lowers the gate lock lever 28 once raised when the worker gets out of the driver's seat. Thereby, the contact 33a of the gate lock switch 33 is closed, the solenoid 37a of the electromagnetic valve 37 is energized, and the electromagnetic valve 37 is switched to the communication position 37R. In this state, the operation lever device 31 can be operated.

  FIG. 9 is a diagram showing changes in the switch 23 and the solenoid valve solenoid 37a until the operator's cab 7 is tilted up from such a state for maintenance and inspection, and then the operator's cab 7 is tilted down again. In the state where the cab 7 is tilted down, the switch 23 is in the B position as described above, and is ON (closed) (S101). At this time, since the gate lock lever 28 is lowered, the gate lock switch 33 is also closed, and the solenoid valve solenoid 37a is energized (ON) (S101).

  When the cab 7 is tilted up, the button 71 of the switch 23 is switched from the position B to the position A, and the switch 23 is turned OFF (S102). As a result, the energization of the solenoid valve solenoid 37a is released and the solenoid valve solenoid 37a is turned off (S103), so that the solenoid valve 37 is switched to the cutoff position 37L. As a result, transmission of the primary pilot pressure from the pilot pump 32 is cut off, and the operation lever device 31 becomes inoperable. When the operation lever device 31 becomes inoperable as described above, when the cab 7 is tilted up, a tool or the like suddenly collides with the operation lever 81 in the cab 7, or the neutral maintenance mechanism of the operation lever 81 breaks down. Thus, even if the operation lever 81 is tilted, the front working machine is prevented from suddenly operating, and safety is ensured.

  When the maintenance / inspection that does not require the operation of the front work machine is performed after the cab 7 is tilted up, the cab 7 is tilted down when the work is completed.

  When the cab 7 is tilted down, the button 71 of the switch 23 is switched from the position A to the position B, and the switch 23 is turned on (S104). Therefore, since the battery 39 energizes the solenoid valve solenoid 37a via the switch 23, the solenoid valve solenoid 37a is turned on (S105), and the solenoid valve 37 is switched to the communication position 37R. As a result, the primary pilot pressure from the pilot pump 32 is guided to the pressure reducing valves 38A and 38B, the operation lever device 31 becomes operable, and the operation pilot pressure is output by the operation of the operation lever 81 to drive the hydraulic cylinder 80. Can do.

  When the operator's cab 7 is tilted up and the front work machine is temporarily moved for maintenance and inspection, the button 71 of the switch 23 is pulled up to switch from the position B to the position C. Turn on (S106). As a result, the battery 39 energizes the solenoid valve solenoid 37a via the switch 23, so that the solenoid valve solenoid 37a is turned on (S107), and the solenoid valve 37 is switched to the communication position 37R. As a result, in this case as well, the operation lever device 31 becomes operable, and the operation pilot pressure is output by the operation of the operation lever 81, and the hydraulic cylinder 80 can be driven.

  Further, when it is desired to perform the inspection while prohibiting the operation of the front work machine again from this state, the button 71 of the switch 23 is pushed down to switch from the position C to the position A, and the switch 23 is turned OFF (S110). As a result, the solenoid valve solenoid 37a is turned OFF (S111), and the solenoid valve 37 is switched to the cutoff position 37L. As a result, transmission of the primary pilot pressure from the pilot pump 32 is cut off, and the operation lever device 31 becomes inoperable.

  Here, when the button 71 of the switch 23 is pulled up again and switched to the position C (ON), the solenoid valve solenoid 37a is turned on as described above, and the solenoid valve 37 is switched to the communication position 37R (S106, S107). ), The operation lever device 31 becomes operable again.

  When the maintenance / inspection work in which the front work machine is operated is finished, the cab 7 is tilted down. As a result, similarly to the steps S104 and S105 described above, the switch 23 is turned on at the B position (S108), the solenoid valve solenoid 37a is also turned on (S109), and the operation lever device 31 is operable.

As described above, according to the present embodiment, when the cab 7 is tilted up, the operation of the front work machine is prohibited, so that the operation lever 81 in the cab 7 is unexpectedly moved during the tilt-up operation. If the operation lever 81 is tilted due to a collision of the operation lever 81 or a failure of the support portion of the operation lever 81, the front work machine is prevented from suddenly operating, and safety during the tilt-up operation of the cab 7 is ensured. Can do.
In addition, the front work machine can be operated as needed after tilting up. If you want to operate the front work machine with the cab 7 tilted up to check the operation of hydraulic equipment, etc. The machine can be operated easily.
Further, since the safety device 44 is configured by the electromagnetic valve 37 switched by the gate lock lever 28, a simple and inexpensive configuration can be achieved. Further, by using the switch 23 that can be switched to the three positions, the safety device 44 can be configured to be simple and inexpensive.

  A second embodiment of the present invention will be described with reference to FIGS. FIG. 10 is an enlarged view of a main part of a small hydraulic excavator according to the second embodiment of the present invention, and shows a state where the cover and the like are removed and the cab 7 is tilted up as in FIG. In the figure, the same components as those shown in FIGS. 1 to 6 are denoted by the same reference numerals.

  In FIG. 10, two switches 73 and 74 are provided side by side in the front-rear direction on the vertical plate 57 on the revolving frame 4. The switch 73 is a normally open (OFF) momentary switch, and the switch 74 is a normally closed (ON) momentary switch. In the state where the cab 7 is tilted down, the buttons 73 and 74 are pressed by the floor board 50, so that the switch 73 is turned on and the switch 74 is turned off. Further, when the cab 7 is tilted up, the load on the buttons of the switches 73 and 74 is released, so the switches 73 and 74 return to the normal state, the switch 73 is turned off, and the switch 74 is turned on. Further, since the switch 73 is located farther from the switch 74 with respect to the floor support mechanism 53, which is the pivot point of the cab 7, the switch 73 and the switch 74 are arranged in the process in which the cab 7 is tilted up. Are switched from ON to OFF and from OFF to ON, respectively, and in the process of tilting down the cab 7, the switches 74 and 73 are switched from ON to OFF and from OFF to ON, respectively. In this case, the height of the button of the switch 73 may be made lower than the height of the button of the switch 74, so that the switch 73 and the switch 74 are reliably switched in that order.

FIG. 11 is a diagram showing a circuit configuration of a hydraulic drive apparatus including a safety device according to the second embodiment of the present invention. In the figure, the same parts as those shown in FIG.
In FIG. 11, reference numeral 44 </ b> A is the safety device of the present embodiment, and this safety device 44 </ b> A has the above-described switch 73, switch 74, and relay 40. The switch 73, the switch 74, and the relay 40 are provided between the electromagnetic valve 37 and the battery 39. Further, the switch 73 and the switch 74 are connected in series, the switch 73 is connected to the battery 39 side, and the switch 74 is connected to the electromagnetic valve 37 side. The relay 40 is composed of a solenoid 40a and a normally closed relay switch 40b that is switched from OFF to ON by energizing the solenoid 40a. The solenoid 40a is on a line branched between the switch 73 and the switch 74, The relay switch 40 b is connected between the battery 39 and the solenoid 37 a of the solenoid valve 37 in parallel with the switch 73 and the switch 74. Other configurations are the same as those in the first embodiment.

  In the above, the electromagnetic valve 37, the switch 73, the switch 74, and the relay 40 constitute an operation control means for prohibiting the operation of the front work machine 3 when the cab 7 as a cab is tilted up. The switch 73, the switch 74, and the relay 40 are in a state in which the operation of the front work machine 3 is inhibited by the manual operation, that is, by manually pressing the switch 73 in the state where the cab 7 is tilted up. The prohibition canceling means for canceling is configured.

  Further, the switch 73, the switch 74, and the relay 40 constitute switching control means for switching the electromagnetic valve 37 from the communication position to the cutoff position when the cab 7 is tilted up. The electromagnetic valve 37 is supplied from a battery 39 as a power source. When the current is supplied, it operates to constitute an electromagnetic switching means that disables the front work machine 3, and the switch 73, the switch 74, and the relay 40 can cut off the supply of current from the battery 39 to the electromagnetic switching means. The switch means is configured.

  Next, the operation of the safety device 44A including the switch 73 and the switch 74 will be described.

FIG. 12 shows the switch 73, the switch 74, and the solenoid valve solenoid 37a until the cab 7 is tilted up with the gate lock lever 28 lowered to perform maintenance and inspection, and then the cab 7 is tilted down again. It is a figure similar to FIG. 10 which shows a change.
When the cab 7 is tilted down, the switch 73 is turned on and the switch 74 is turned off (S201). At this time, the solenoid 40a of the relay 40 is energized, the relay switch 40b is closed, and the relay 40 is turned on (S201). At this time, since the gate lock lever 28 is lowered, the gate lock switch 33 is also closed. Therefore, in this state, the battery 39 energizes the solenoid valve solenoid 37a via the switch 73 and the relay 40, the solenoid valve solenoid 37a is turned on (S201), and the solenoid valve 37 is moved to the communication position 37R shown on the right side in FIG. Can be switched. As a result, the primary pilot pressure from the pilot pump 32 is guided to the pressure reducing valves 38A and 38B, the operation lever device 31 becomes operable, and the operation pilot pressure is output by the operation of the operation lever 81 to drive the hydraulic cylinder 80. can do.

  When the cab 7 is tilted up, the switch 73 is first turned off (S202), and then the switch 74 is turned on (S205). At the same time as the switch 73 is turned off, the energization of the solenoid 40a of the relay 40 is cut off, the relay switch 40b of the relay 40 is turned off, and the relay 40 is turned off (S203). As a result, the energization of the solenoid valve solenoid 37a is released and the solenoid valve solenoid 37a is turned off (S204), so that the solenoid valve 37 is switched to the cutoff position 37L. As a result, transmission of the primary pilot pressure from the pilot pump 32 is cut off, and the operation lever device 31 becomes inoperable. When the operation lever device 31 becomes inoperable as described above, when the cab 7 is tilted up, a tool or the like suddenly collides with the operation lever 81 in the cab 7, or the neutral maintenance mechanism of the operation lever 81 breaks down. Thus, even if the operation lever 81 is tilted, the front working machine is prevented from suddenly operating, and safety is ensured.

  When the maintenance / inspection that does not require the operation of the front work machine is performed after the cab 7 is tilted up, the cab 7 is tilted down when the work is completed.

  When the cab 7 is tilted down, the switch 74 is first turned OFF (S206), and then the switch 73 is turned ON (S207). At the same time as the switch 73 is turned on, the solenoid 40a of the relay 40 is energized, the relay switch 40b of the relay 40 is closed, and the relay 40 is turned on (S208). Accordingly, since the battery 39 energizes the solenoid valve solenoid 37a via the switch 73 and the relay 40, the solenoid valve solenoid 37a is turned on (S209), and the solenoid valve 37 is switched to the communication position 37R. As a result, the primary pilot pressure from the pilot pump 32 is guided to the pressure reducing valves 38A and 38B, the operation lever device 31 becomes operable, and the operation pilot pressure is output by the operation of the operation lever 81 to drive the hydraulic cylinder 80. Can do.

  Further, when it is desired to perform maintenance / inspection by temporarily moving the front work machine with the cab 7 tilted up, the switch 73 is pushed ON by manual operation (S210). As a result, the solenoid 40a of the relay 40 is energized, the relay switch 40b of the relay 40 is closed, and the relay 40 is turned on (S211). Therefore, since the battery 39 energizes the solenoid valve solenoid 37a via the switch 73 and the relay 40, the solenoid valve solenoid 37a is turned on (S212), and the solenoid valve 37 is switched to the communication position 37R. Since the switch 73 is a normally open (OFF) momentary operation switch as described above, when the pressed hand is released, the switch 73 returns to the normal state and the switch 73 is turned OFF (S213). However, since the switch 74 is ON in this state, when the switch 73 is pressed to ON and the relay switch 40b is once closed, the battery 39, the relay switch 40b of the relay 40, the switch 74, the solenoid 40a of the relay 40, and the GND are switched to. Even when the switch 73 returns to OFF, the solenoid 40a continues to be energized and the relay 40 remains ON. As a result, the electromagnetic valve 37 holds the communication position 37 </ b> R, the operation lever device 31 can be operated, the operation pilot pressure is output by the operation of the operation lever 81, and the hydraulic cylinder 80 can be driven.

  In addition, when it is desired to perform the inspection while prohibiting the operation of the front work machine again from this state, the switch 74 is manually turned off (S218). As a result, the above circuit is cut off, the relay 40 is turned off (S219), the solenoid valve solenoid 37a is turned off (S220), and the solenoid valve 37 is switched to the cutoff position 37L. Thereafter, when the hand is released from the switch 74, the switch 74 is turned on. However, since the relay switch 40b is already OFF at this time, as long as the switch 73 is OFF, the relay 40 remains OFF and the electromagnetic valve 37 maintains the cutoff position 37L. As a result, transmission of the primary pilot pressure from the pilot pump 32 is cut off, and the operation lever device 31 becomes inoperable.

  Here, when the switch 73 is pressed again and turned on, the relay 40 is turned on as described above, the electromagnetic valve 37 is switched to the communication position 37R (S210, S211, S212, S213), and the operation lever device 31 is It becomes operational again.

  When the maintenance / inspection work in which the front work machine is operated is finished, the cab 7 is tilted down. As a result, the switch 74 is turned off (S214) and the switch 73 is turned on (S215) similarly to the above-described steps S206, S207, S208, and S209, and the relay 40 is turned on (S216). As a result, the solenoid valve solenoid is turned on. 37a is turned on (S217), and the operation lever device 31 becomes operable.

As described above, according to the present embodiment, when the cab 7 is tilted up, the operation of the front work machine is prohibited, so that the operation lever 81 in the cab 7 is unexpectedly moved during the tilt-up operation. If the operation lever 81 is tilted due to a collision of the operation lever 81 or a failure of the support portion of the operation lever 81, the front work machine is prevented from suddenly operating, and safety during the tilt-up operation of the cab 7 is ensured. Can do.
In addition, the front work machine can be operated as needed after tilting up. If you want to operate the front work machine with the cab 7 tilted up to check the operation of hydraulic equipment, etc. The machine can be operated easily.
Further, since the safety device 44 is configured by the electromagnetic valve 37 switched by the gate lock lever 28, a simple and inexpensive configuration can be achieved. Further, by using a momentary operation switch that is easily available, the safety device 44 can be made inexpensive.

A third embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a diagram showing a circuit configuration of a hydraulic drive apparatus including a safety device according to the third embodiment of the present invention. In the figure, the same parts as those shown in FIG.
In FIG. 13, reference numeral 44 </ b> B is a safety device of the present embodiment, and this safety device 44 </ b> B has a stop solenoid valve 43 in addition to that of the second embodiment shown in FIG. 11. The stop solenoid valve 43 is provided between the engine 34 and the fuel tank 42. By switching the energization of the stop solenoid 43a, the flow of fuel supplied from the fuel tank 42 to the engine 34 via the fuel pump 44 is permitted and cut off. Is. That is, the supply of fuel is permitted when the stop solenoid 43a is energized (ON), and the fuel flow is interrupted when the stop solenoid 43a is deenergized (OFF). The stop solenoid 43a is connected to the battery 39 in parallel with the solenoid valve solenoid 37a via the relay switch 40b and the switch 74 of the relay 40, and is turned ON and OFF simultaneously with the switching of the solenoid valve solenoid 37a.
The other configuration is the same as that of the second embodiment.

  In the above, the electromagnetic valve 37, the stop solenoid valve 43, the switch 73, the switch 74, and the relay 40 constitute an operation control means for prohibiting the operation of the front work machine 3 when the cab 7 as a cab is tilted up. The solenoid valve 37, the stop solenoid valve 43, the switch 73, the switch 74, and the relay 40 are operated by the operation restricting means when the cab 7 is tilted up, by manually pressing the switch 73 manually. A prohibition canceling means for canceling the prohibition state of the operation of the front work machine 3 is configured.

  Further, the stop solenoid valve 43, the switch 73, the switch 74, and the relay 40 constitute fuel supply stop means for stopping the supply of fuel to the engine 34 when the cab 7 is tilted up, and the electromagnetic valve 37 and the stop solenoid. The valve 43 is operated when current is supplied from the battery 39 as the power source, and constitutes electromagnetic switching means for disabling the front work machine 3. The switch 73, the switch 74, and the relay 40 are connected to the electromagnetic from the battery 39. The switch means is configured to cut off the supply of current to the switching means.

  Next, the operation of the safety device of the present invention including the stop solenoid valve 43 will be described.

FIG. 14 shows the switch 73, the switch 74, and the solenoid valve solenoid 37a until the cab 7 is tilted up for maintenance / inspection with the gate lock lever 28 lowered and then the cab 7 is tilted down again. It is a figure similar to FIG. 12 which shows a change and the change of the state of the stop solenoid 43a and the engine 34. FIG.
When the cab 7 is tilted down, the switch 73 is ON, the switch 74 is OFF, the relay 40 is ON, the solenoid valve solenoid 37a is ON (S301), and the solenoid valve 37 is as shown in FIG. It is switched to the communication position 37R shown on the middle right side. Further, the stop solenoid 43a is also turned on (S301), the stop solenoid valve 43 permits fuel supply, and the engine 34 is in an operating state.

  When the cab 7 is tilted up, the switch 73 is first turned off (S302), and then the switch 74 is turned on (S306). As a result, as in the case of FIG. 12, the relay 40 is turned off (S303), the solenoid valve solenoid 37a is turned off (S304), and the solenoid valve 37 is switched to the cutoff position 37L. As a result, transmission of the primary pilot pressure from the pilot pump 32 is cut off, and the operation lever device 31 becomes inoperable. At the same time as the solenoid valve solenoid 37a is turned off, the stop solenoid 43a is also turned off (S304), the stop solenoid valve 43 shuts off the fuel supply, and the engine 34 is stopped (S305). When the engine 34 is stopped in this manner, the drive of the hydraulic pump 35 is also stopped. Therefore, when the cab 7 is tilted up, a tool or the like unexpectedly collides with the operation lever 81 in the cab 7, or the operation lever 81 Even if the operation lever 81 is tilted due to a failure of the neutral maintenance mechanism, the operation of the front work machine is prohibited, and safety is ensured. Further, since the engine 34 is stopped, the rotation of the engine cooling fan (not shown) is stopped, and the drive of the hydraulic pump 35 is stopped, so that the hydraulic pressure becomes the tank pressure. There is no danger in contact with the hose, and safety is further improved. Further, even if the stop solenoid 43a is turned OFF and the stop solenoid valve 43 cuts off the fuel supply, the remaining fuel in the fuel pipe is supplied to the engine 34, so the engine 34 does not stop immediately. However, since the solenoid solenoid 37a is also turned off at the same time as the stop solenoid 43a is turned off prior to the stop of the engine 34, the solenoid valve solenoid is kept until the engine 34 is stopped after the stop solenoid 43a is turned off. The operation lever device 31 becomes inoperable by turning OFF 37a, and safety during that time is also ensured.

  When the maintenance / inspection that does not require the operation of the front work machine is performed after the cab 7 is tilted up, the cab 7 is tilted down when the work is completed.

  When the cab 7 is tilted down, the switch 74 is first turned OFF (S307), and then the switch 73 is turned ON (S308). Accordingly, as in the case of FIG. 12, the relay 40 is turned on (S309), the solenoid valve solenoid 37a is turned on (S310), and the solenoid valve 37 is switched to the communication position 37R. At the same time, the stop solenoid 43a is turned on (S310), the stop solenoid valve 43 permits the supply of fuel, and the engine 34 can be operated. Thereby, if the engine 34 is started, the operation lever device 31 becomes operable.

  Further, when it is desired to perform maintenance / inspection by temporarily moving the front work machine with the cab 7 tilted up, the switch 73 is pushed and turned on manually (S311). Accordingly, as in the case of FIG. 12, the relay 40 is turned on (S312), the solenoid valve solenoid 37a is turned on (S313), and the solenoid valve 37 is switched to the communication position 37R. At the same time, the stop solenoid 43a is also turned on (S313), the stop solenoid valve 43 permits fuel supply, and the engine 34 can be operated. Accordingly, the operation lever device 31 can be operated, and the operation pilot pressure is output by the operation of the operation lever 81, and the hydraulic cylinder 80 can be driven.

Further, when it is desired to perform the inspection while prohibiting the operation of the front work machine again from this state, the switch 74 is pushed OFF by manual operation (S320). As a result, the relay 40 is turned off (S321), the solenoid valve solenoid 37a is turned off (S322), and the solenoid valve 37 is switched to the cutoff position 37L. At the same time, the stop solenoid 43a is also turned off (S322), the stop solenoid valve 43 shuts off the fuel supply, and the engine 34 is stopped (S323). As a result, the operation lever device 31 becomes inoperable and the engine cooling fan and the like also stop.
Here, if the switch 73 is pressed again and turned on, the relay 40 is turned on as described above, the solenoid valve 37 is switched to the communication position 37R, and the stop solenoid 43a is also turned on, so that the engine 34 can be operated. If the engine is started in this state, the operation lever device 31 can be operated again (S311, S312, S313, S314, S315).

  When the maintenance / inspection work in which the front work machine is operated is finished, the cab 7 is tilted down. As a result, the switch 74 is turned off (S316), the switch 73 is turned on (S317), the relay 40 is turned on (S318), and the solenoid valve solenoid 37a is turned on in the same manner as the steps S307, S308, S309, and S310 described above. At the same time, the stop solenoid 43a is also turned on (S319). As a result, the engine 34 can be operated, and when the engine 34 is started, the operation lever device 31 is also operable.

As described above, according to the present embodiment, when the cab 7 is tilted up, the operation of the front work machine is prohibited, so that the operation lever 81 in the cab 7 is unexpectedly moved during the tilt-up operation. If the operation lever 81 is tilted due to a collision of the operation lever 81 or a failure of the support portion of the operation lever 81, the front work machine is prevented from suddenly operating, and safety during the tilt-up operation of the cab 7 is ensured. Can do.
In addition, the front work machine can be operated as needed after tilting up. If you want to operate the front work machine with the cab 7 tilted up to check the operation of hydraulic equipment, etc. The machine can be operated easily.
Also, by stopping the engine when tilting up, the rotation of the engine cooling fan stops and the main hydraulic pump stops driving, and the oil pressure becomes the tank pressure, so service personnel come into contact with the engine cooling fan and hoses. There is no danger, and the safety during the tilt-up operation of the cab 7 is further improved.
Further, even if the stop solenoid valve 43 cuts off the fuel supply, the remaining fuel in the fuel pipe is supplied to the engine 34. Therefore, the engine 34 does not stop immediately, but prior to the engine 34 being stopped, the stop solenoid 43a Since the solenoid valve solenoid 37a is also turned off simultaneously with turning off, the operation lever device 31 becomes inoperable by turning off the solenoid valve solenoid 37a until the engine 34 is stopped after the stop solenoid 43a is turned off. Safety during that time is also ensured.
Further, since the safety device 44 is configured by the electromagnetic valve 37 switched by the gate lock lever 28, a simple and inexpensive configuration can be achieved. Further, by using a momentary operation switch that is easily available, the safety device 44 can be made inexpensive.

  In the above embodiment, as the operation system of the control valve 36, the pressure reducing valves 38A and 38B for outputting the operation pilot pressure according to the operation amount of the operation lever 81 based on the primary pilot pressure from the pilot pump 32 are provided. The present invention is applied to a hydraulic pilot system, but the operation of the operation lever is electrically detected, the electric signal is input to the controller, a control signal is generated, and the solenoid valve is operated based on the control signal. The present invention may be applied to an electric lever system that is driven to generate an operation pilot pressure.

  In the above embodiment, the present invention is applied to a hydraulic excavator including a cabin type cab 7 as a cab. However, the present invention is applied to a hydraulic excavator having a canopy type cab in which the left and right fronts are released. Also good.

  In the above embodiment, the stop solenoid is used. However, as long as the fuel supply is stopped as a means for stopping the rotation of the engine, not only the stop solenoid but also a fuel pump and an electronic governor may be used. good.

It is a side view showing the whole structure of the small hydraulic excavator which is the application object of the safety device of the construction machine of the present invention. It is a side view showing the inside of the cab of the small hydraulic excavator which is the application object of the safety device of the construction machine of the present invention. A part of the outer cover of the upper swing body of the small excavator equipped with the first embodiment of the safety device for a construction machine of the present invention, the engine, the tank, etc. are removed, and the cab 7 is tilted up from the right front side. It is an external perspective view. It is a side view which shows the principal part of the upper turning body of the state which removed the exterior cover, the engine, the tank, etc. of the small hydraulic excavator provided with 1st Embodiment of the safety device of the construction machine of this invention. It is a side view which shows the state which removed the exterior cover, the engine, the tank, etc. of the small hydraulic excavator provided with 1st Embodiment of the safety device of the construction machine of this invention, and the cab 7 was tilted up. . It is an external appearance perspective view which expands and shows the tilting mechanism of the small hydraulic shovel which is the application object of the safety device of the construction machine of this invention. It is an enlarged view of the switch part which comprises 1st Embodiment of the safety device of the construction machine of this invention. It is a figure which shows the hydraulic drive device of the small hydraulic excavator provided with 1st Embodiment of the safety device of the construction machine of this invention. The change of the state of the safety device until the cab of the small hydraulic excavator provided with the first embodiment of the safety device of the construction machine of the present invention is tilted up for maintenance and then the cab is tilted down again is shown. FIG. It is an enlarged view of the revolving frame part of the state which removed the exterior cover, the engine, the tank, etc. of the small hydraulic excavator provided with 2nd Embodiment of the safety device of the construction machine of this invention. It is a figure which shows the hydraulic drive device of the small hydraulic excavator provided with 2nd Embodiment of the safety device of the construction machine of this invention. The change of the state of the safety device until the cab of the small hydraulic excavator provided with the second embodiment of the safety device of the construction machine of the present invention is tilted up for maintenance and then tilted down again is shown. FIG. It is a figure which shows the hydraulic drive device of the small hydraulic excavator provided with 3rd Embodiment of the safety device of the construction machine of this invention. The change of the state of the safety device until the cab of the small hydraulic excavator equipped with the third embodiment of the safety device of the construction machine according to the present invention is tilted up for maintenance and then tilted down again is shown. FIG.

Explanation of symbols

1 Lower traveling body (traveling body)
2 Upper swing body (swivel body)
3 Front work machine 4 Swivel frame 7 Driver's cab (cab)
25 Driver's seat 28 Gate lock lever 31 Operation lever device 32 Pilot pump 34 Engine 35 Hydraulic pump (main hydraulic pump)
36 Control valve 37 Solenoid valve 39 Battery (power supply)
40 relay 73 switch (first switch)
74 switch (second switch)
80 Hydraulic cylinder (hydraulic actuator)
81 Control lever

Claims (7)

A traveling body, a revolving body, and a front working machine, the revolving body includes a revolving frame and a cab, and an operation lever and a driver's seat for operating the front working machine and the revolving body are disposed on the cab. In a safety device for a construction machine having a structure that supports the cab so that it can tilt forward with respect to the swivel frame, and the cab can be tilted up,
A safety device for a construction machine, comprising operation restriction means for prohibiting the operation of the front work machine when the cab is tilted up. The safety device for a construction machine according to claim 1,
A safety device for a construction machine, further comprising: a prohibition canceling unit that cancels the prohibition state of the operation of the front work machine by the operation restricting unit by manual operation when the cab is tilted up. The safety device for a construction machine according to claim 1,
The construction machine supplies a main hydraulic pump, a plurality of hydraulic actuators driven by pressure oil discharged from the hydraulic pump to drive the front work machine and the swing body, and a supply from the main hydraulic pump to the plurality of hydraulic actuators. A plurality of control valves for controlling the flow of pressure oil, a pilot pump, and the operation lever, and generating a pilot secondary pressure using the discharge pressure of the pilot pump as a pilot primary pressure, the pilot operated control An operation lever device for switching a valve,
The operation restricting means is provided in a pilot primary pressure line that guides a pilot primary pressure from the pilot pump to the operation lever device, and an electromagnetic valve that switches communication / blocking of the pilot primary pressure line, and the cab tilts up. And a switching control means for switching the solenoid valve from the communication position to the shut-off position when it is operated. The safety device for a construction machine according to claim 3,
The construction machine further includes a gate lock lever arranged in the cab, and the electromagnetic valve is an electromagnetic valve that is switched by the gate lock lever. The safety device for a construction machine according to claim 1,
The construction machine includes a main hydraulic pump, a plurality of hydraulic actuators that are driven by pressure oil discharged from the hydraulic pump to drive the front work machine, and an engine that drives the main hydraulic pump,
The safety device for a construction machine, wherein the operation restricting means is fuel supply stopping means for stopping supply of fuel to the engine when the cab is tilted up. The safety device for a construction machine according to claim 1,
The operation restricting means operates when a current is supplied from the power supply and the power supply, and the electromagnetic switching means for disabling the front work machine, and the supply of current from the power supply to the electromagnetic switching means can be cut off. A first position that is closed when the cab is tilted down, a second position that is open when the cab is tilted up, and a second position of the switch means. A safety device for a construction machine, having a third position that is closed by manual operation when the position is maintained, and maintains the state. The safety device for a construction machine according to claim 1,
The operation restricting means operates when a current is supplied from the power supply and the power supply, and the electromagnetic switching means for disabling the front work machine, and the supply of current from the power supply to the electromagnetic switching means can be cut off. The switch means includes first and second switches connected in series, and a relay connected in parallel to the first and second switches, the first and second switches. The second switch is a switch that closes the first switch and opens the second switch when the cab is tilted down, and closes the first switch and opens the second switch when the cab is tilted up. Yes, the relay is turned on when the first switch is closed, and once turned on while the second switch is closed, then the relay is kept on even when the first switch is opened. When the cab tilts up, the first and second switches are switched in the order of the first switch and the second switch, and when the cab tilts down, the first and second switches A safety device for a construction machine, wherein the switch is arranged so as to be switched in the order of 1 switch and 2nd switch.

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