Construction machine

Abstract

To provide a construction machine capable of giving a sense of security to an operator when starting an engine.SOLUTION: A hydraulic shovel 1 comprises: a hydraulic pump 106 and a pilot oil pump 107; a plurality of hydraulic actuators; a plurality of operation levers 14, 25 provided in a driver's cab for operating the plurality of hydraulic actuators using pilot pressure oil from the pilot oil pump 107; a shut-off lever 20 that can be rotated between a locked position that disables operation of the operating levers 14, 25 and an unlocked position that enables operation of the operating levers 14, 25; an engine start switch 32; and an engine control portion 102j. The hydraulic shovel 1 has an engine start preparation switch 30 for preparing start of an engine 109, and the engine start preparation switch 30 is arranged on the shut-off lever 20.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a construction machine equipped with a shutoff lever. [Background technology]

[0002] Patent Document 1 discloses a control device for a work machine, which includes an engine as a power source that is started by a starter motor based on the operation of an engine switch, a hydraulic pump and a pilot oil pump driven by the engine, multiple hydraulic actuators driven by the hydraulic pump, multiple operating bodies that command the operation of the multiple hydraulic actuators, a control valve that controls the direction and flow rate of pressurized oil supplied from the hydraulic pump to the multiple hydraulic actuators, a pilot oil passage that supplies pressurized oil from the pilot oil pump to an operating section of the control valve via the operating body, engine control means that can perform auto idling stop control that automatically stops the engine when a preset auto idling stop condition is met, a shutoff lever (gate lock lever) that is provided in the driver's cab and can be rotated between a locked position (raised position) that disables operation of the operating body and an unlocked position (pushed down position) that enables operation of the operating body, and an engine start switch.

[0003] In Patent Document 1, when an operator operates an engine start switch, the starter motor starts, causing the engine drive shaft to rotate and start the engine. On the other hand, when the operator operates the shutoff lever to the lock position, pressure oil from the pilot oil pump is cut off and is no longer introduced to the operating part of the control valve. As a result, the operation of the control valve by the operating body is disabled, and the work machine is locked so that it cannot operate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-237161 A Summary of the Invention [Problem to be solved by the invention]

[0005] For example, push start switches have been introduced in recent automobiles. The driver operates the shift lever to the parking position, depresses the foot brake, and operates the push start switch to start the engine. In other words, depressing the foot brake is essential to start the engine. Therefore, the driver is aware that he or she is operating the brake and, at the same time, is starting the engine, so that the driver can feel secure that the car will not move off even if the engine starts.

[0006] On the other hand, in construction machines such as hydraulic excavators as described above, there are cases where a brake equivalent to a foot brake in an automobile does not exist. In the above-mentioned conventional technology, even if the engine start switch is operated to start the engine, the work machine will not operate as long as the shutoff lever is operated to the lock position, so a technology is adopted that allows the engine to start on the condition that the shutoff lever is in the lock position. However, the shutoff lever is operated in advance and is not operated by the operator at the same time as starting the engine, so it is not possible to obtain the same sense of security as in the case of an automobile.

[0007] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a construction machine that can give an operator a sense of security when starting the engine. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides a construction machine comprising an engine as a power source, a hydraulic pump and a pilot oil pump driven by the engine, a plurality of hydraulic actuators driven by the hydraulic pump, a plurality of operating levers provided in a driver's cab for operating the plurality of hydraulic actuators using pilot pressure oil from the pilot oil pump, a shut-off lever provided in the driver's cab and rotatable between a locked position for disabling operation of the operating lever and an unlocked position for enabling operation of the operating lever, a starter motor drive switch for driving a starter motor, and an engine control unit for driving the starter motor by the starter motor drive switch to start the engine, the construction machine having an engine start preparation switch for preparing for starting of the engine by the starter motor drive switch, and the engine start preparation switch is disposed on the shut-off lever. Effect of the Invention

[0009] According to the present invention, it is possible to give a sense of security to an operator when starting an engine. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a left side view showing a hydraulic excavator according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a hydraulic circuit diagram relating to actuator drive of the hydraulic excavator. [Diagram 3] FIG. 2 is a control block diagram showing the flow of control signals. [Figure 4] FIG. 2 is an explanatory diagram illustrating the contents of a control logic incorporated in an engine control unit. [Diagram 5] FIG. 2 is a perspective view showing a driver's seat provided in a cab. [Figure 6] FIG. 2 is a perspective view of the right console device as seen from above. [Figure 7] FIG. 2 is a perspective view of the left console device as viewed diagonally from above on the left side. [Figure 8]FIG. 13 is a left side view illustrating the shutoff lever in an unlocked position. [Figure 9] FIG. 4 is a left side view showing the shutoff lever in a locked position. [Figure 10] 10(a) is a left side view showing an engine start preparation switch and its surrounding area in detail, FIG. 10(b) is a view taken along an arrow A in FIG. 10(a), and FIG. 10(b) is an operation explanatory diagram of the engine start preparation switch. [Figure 11] 11A is a left side view showing a schematic diagram of another example of an engine start preparation switch and its surrounding area, a view taken along the line B in FIG. 11A, and an operation explanatory diagram of the engine start preparation switch. [Figure 12] 12(a) and 12(b) are a left side view and a view taken along the arrow C in FIG. 12(a), which show a schematic diagram of an engine start preparation switch and its surrounding area according to a comparative example. [Figure 13] 13(a) and 13(b) are a left side view and a view taken along the arrow D in FIG. 13(a), which show a schematic diagram of an engine start preparation switch and its surrounding area in detail according to another comparative example. [Figure 14] 14(a) and 14(b) are a left side view and a view taken along the arrow E in FIG. 14(a), which show a schematic diagram of an engine start preparation switch and its surrounding area according to still another comparative example. [Figure 15] 15(a) is a left side view showing a schematic diagram of the engine start preparation switch and its surrounding area in a modified example in which the engine start preparation switch is provided on the inner upper wall portion of the recess, a view seen from the arrow F1 in FIG. 15(a), an operation explanatory diagram of the engine start preparation switch, and a view seen from the arrow F2 in FIG. 15(c). [Figure 16] 16(a) and 16(b) are a left side view and a view taken along arrow G in FIG. 16(a), which show schematic details of an engine start preparation switch and its surrounding area in a modified example in which the engine start preparation switch is provided on the top of the operating part facing the unlocking direction. [Figure 17] 17(a) and 17(b). FIG. 17(a) is a left side view showing a schematic diagram of the engine start preparation switch and its surrounding area in a modified example in which the engine start preparation switch is arranged facing the unlocking direction side of the upper surface of the operating unit. [Figure 18]18(a) and 18(b) are a left side view and a view taken along the arrow I in FIG. 18(a), which show a schematic diagram of an engine start preparation switch and its surrounding area in a modified example in which the engine start preparation switch is provided on the inner lower wall of a recessed portion. [Figure 19] This is a left side view showing the locked position of the shutoff lever in a modified example in which the engine start preparation switch is located at a position away from the shutoff lever, and a left side view showing the state in which the engine start preparation switch is operated by rotating it in the opposite direction to the rotation to the unlocked position. [Figure 20] This is a left side view showing the locked position of the shutoff lever in another modified example in which the engine start preparation switch is located at a position away from the shutoff lever, and a left side view showing the state in which the engine start preparation switch is operated by rotating it in the opposite direction to the rotation to the unlocked position. [Figure 21] FIG. 11 is an explanatory diagram showing the contents of a control logic incorporated in an engine control unit in a modified example in which the function of the engine start switch is transferred to an engine start preparation switch and integrated into one switch. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An embodiment of the present invention will be described in detail below with reference to the accompanying drawings, taking as an example a case where the present invention is applied to a hydraulic excavator. In this embodiment, the traveling direction of the hydraulic excavator is defined as the front-rear direction, and the direction perpendicular to the traveling direction of the hydraulic excavator is defined as the left-right direction.

[0012] <Overall configuration of hydraulic excavator> In Fig. 1, a hydraulic excavator 1, which is an example of a construction machine of this embodiment, includes a crawler-type lower traveling body 2 that is self-propelled in the front-rear direction, and an upper rotating body 3 that is rotatably mounted on the lower traveling body 2. The lower traveling body 2 and the upper rotating body 3 form the body of the hydraulic excavator 1. A working device 4 is provided in front of the upper rotating body 3 so that it can be elevated and lowered. The hydraulic excavator 1 travels on the lower traveling body 2 at a work site, and performs work such as excavating earth and sand by elevating and lowering the working device 4 while rotating the upper rotating body 3.

[0013] The upper rotating body 3 has a rotating frame 5 that serves as a base. A counterweight 6 is provided on the rear side of the rotating frame 5 to balance the weight with the work implement 4. An engine 109 serving as a power source, a hydraulic pump 106, a pilot oil pump 107, a heat exchanger, and other on-board equipment (see FIG. 2, etc., described later) are mounted on the rotating frame 5. These on-board equipment are covered by an exterior cover 7 provided on the rotating frame 5. A cab 8 that defines the operator's compartment is provided on the front left side of the upper rotating body 3.

[0014] The cab 8 is formed in a box shape rising upward from the revolving frame 5, and a driver's compartment is defined inside the cab 8. On the left side of the cab 8, there are provided an access door 8A for an operator (operator) to get in and out of the cab 8, and a door 8B for opening and closing the access door 8A. In addition, in the driver's compartment inside the cab 8, there are provided a driver's seat 10, a left console device 11, a shutoff device 19, a right console device 24, etc., which will be described later.

[0015] As shown in FIG. 1, the working device 4 is composed of an articulated working device 4 consisting of a boom 101a, an arm 101b, and a bucket 101c, each of which rotates vertically, and a vehicle body consisting of an upper rotating body 3 and a lower running body 2, and the base end of the boom 101a of the working device 4 is supported at the front of the upper rotating body 3.

[0016] The boom 101a is supported on the front of the upper rotating body 3 so as to be able to move up and down, and is driven by a boom cylinder 103a. The arm 101b is rotatably supported on the boom 101a, and is driven by an arm cylinder 103b. The bucket 101c is rotatably supported on the arm 101b, and is driven by a bucket cylinder 103c. The upper rotating body 3 is driven to rotate by a swing motor 103d, and the lower traveling body 2 is driven by left and right traveling motors 103e, 103f. The drive of the hydraulic actuators, the boom cylinder 103a, the arm cylinder 103b, the bucket cylinder 103c, and the swing motor 103d, is controlled by operation levers 14, 25 (see FIG. 2, etc. described later) that are installed in the cab 8 of the upper rotating body 3 and output hydraulic signals.

[0017] <Hydraulic circuit> FIG. 2 is a hydraulic circuit diagram relating to actuator drive of the hydraulic excavator of this embodiment.

[0018] The hydraulic circuit shown in Fig. 2 includes a hydraulic pump 106 as a hydraulic source (drive source) for the hydraulic actuator, a pilot oil pump 107 as a hydraulic source (drive source) for pilot pressure oil, and a hydraulic oil tank 108. The hydraulic pump 106 and the pilot oil pump 107 are connected to the same drive shaft, and are driven by an engine 109 connected in series to this drive shaft. In addition, a pulley 123a is provided on the drive shaft between the engine 109 and the hydraulic pump 106, and the pulley 123a is connected to the rotating shaft of a starter motor 123 via a belt 123b.

[0019] A relief valve 130A and control valves 105a to 105f are provided in an oil passage 130 that supplies pressure oil from the hydraulic pump 106 to the boom cylinder 103a to the traveling motor 103f. The relief valve 130A limits the pressure of the pressure oil in the oil passage 130. The control valves 105a to 105f control the direction and flow rate of the pressure oil in the oil passage 130. The control valves 105a to 105f have their spool positions switched by the supply of pilot pressure oil from pilot secondary oil passages 144a to 144f to the pilot operation units. As a result, the control valves 105a to 105f supply pressure oil from the hydraulic pump 106 to each hydraulic actuator to drive the boom 101a, the arm 101b, the bucket 101c, etc.

[0020] The spool positions of the control valves 105a to 105f are switched by operating the operation levers 14, 25, etc. By operating the operation levers 14, 25, etc., pilot primary pressure oil supplied from the pilot oil pump 107 via pilot primary side oil passages 140, 141 is supplied to the pilot operation parts of the control valves 105a to 105f through pilot secondary side oil passages 144a to 144f.

[0021] A shutoff electromagnetic switching valve 120 is provided in a pilot primary side oil passage 141, one end of which is connected to the operation levers 14, 25. This shutoff electromagnetic switching valve 120 switches between communication and cut-off of the pilot primary side oil passage 141 in response to a command from a main control unit 102 (hereinafter referred to as MCU 102 as appropriate).

[0022] The other end of the pilot primary oil passage 140 is connected to the discharge portion of the pilot oil pump 107. A relief valve 140A that limits the pressure of the pressurized oil in the oil passage and a filter 114 that prevents impurities from entering the downstream side are provided in the intermediate portion of the pilot primary oil passage 140. A check valve 116 is provided in the pilot primary oil passage 141.

[0023] <Control block> FIG. 3 is a control block diagram showing the flow of control signals according to this embodiment. 3, the MCU 102 includes an input unit, a calculation unit, and an output unit. The calculation unit includes a lock lever control unit 102a and an engine control unit 102j.

[0024] The lock lever control unit 102a inputs the switching state of the shutoff lever 20, and outputs an open / close command to the shutoff electromagnetic switching valve 120 depending on the position. When the shutoff lever 20 is in, for example, the unlocked position (see FIG. 8 described later), the shutoff electromagnetic switching valve 120 is switched to the communicating position. As a result, pressure oil from the pilot oil pump 107 is introduced to the operation levers 14, 25, and operation of the control valves 105a to 105f by the operation levers 14, 25 becomes effective. When the shutoff lever 20 is in, for example, the locked position (see FIG. 9 described later), the shutoff electromagnetic switching valve 120 remains switched to the blocking position, and pressure oil from the pilot oil pump 107 is not introduced to the operation levers 14, 25. As a result, operation of the control valves 105a to 105f by the operation levers 14, 25 becomes ineffective.

[0025] The engine control unit 102j receives, for example, a rotation speed command from an engine control dial 125 provided in the driver's cab, an ON / OFF signal from an engine start switch 32 (starter motor drive switch), and an ON / OFF signal from an engine start preparation switch 30. Based on these, the engine control unit 102j outputs an engine control command to an engine controller 113 (hereinafter, appropriately referred to as ECU) and a starter motor control unit 124.

[0026] A starter motor control unit 124 controls the starter motor 123 to rotate at engine start based on an engine control command from the MCU 102. The ECU 113 controls the fuel injection amount and the rotation speed of the engine 109 based on the engine control command from the MCU 102 so as to achieve a predetermined engine rotation speed.

[0027] <Engine start control by the engine control unit> In this embodiment, when starting the engine 109, the operator needs to operate both the engine start preparation switch 30 and the engine start switch 32. That is, the engine start switch 32 functions as a switch for driving the starter motor 123, and the engine start preparation switch 30 functions as a switch for preparing the start of the engine 109 in which the starter motor 123 is driven by the engine start switch 32. The contents of the control logic incorporated in the engine control unit 102j for realizing the above processing are shown in FIG.

[0028] 4, for example, a state in which neither the engine start preparation switch 30 nor the engine start switch 32 is operated is the so-called KEY-OFF state. When the engine start switch 32 is operated for a relatively long time from this state (a so-called long press; the same applies below), the state transitions to the so-called KEY-ON state. When both the engine start switch 32 and the engine start preparation switch 30 are further operated in this state, an engine control command is output from the engine control unit 102j to the starter motor control unit 124, and the engine 109 is started.

[0029] Furthermore, when the engine start switch 32 is operated for a relatively short time (a so-called short press; the same applies below) in the KEY-OFF state, the state transitions to a so-called ACC state in which electricity is supplied to the electrical components. In this ACC state, when both the engine start switch 32 and the engine start preparation switch 30 are further operated, an engine control command is output from the engine control unit 102j to the starter motor control unit 124, and the engine 109 is started. Note that when only the engine start switch 32 is operated in the ACC state, the state transitions to the KEY-ON state.

[0030] Also, when both the engine start switch 32 and the engine start preparation switch 30 are operated from the KEY-OFF state, an engine control command is output from the engine control unit 102j to the starter motor control unit 124, and the engine 109 is started.

[0031] When the engine start switch 32 is operated in the KEY-ON state or the engine start state, the engine 109 is stopped based on an engine control command sent from the engine control unit 102j to the ECU 113.

[0032] <Driver's seat> The operator's seat 10 provided in the cab 8 of the hydraulic excavator 1 is shown in Fig. 5. As shown in Fig. 5, the operator's seat 10 is composed of an operator's seat base 10A attached to the floor member 9, and a seat 10B attached to the operator's seat base 10A and on which the operator sits. The operator's seat base 10A has a function for adjusting the position of the seat 10B in the vertical and longitudinal directions according to the physique of the operator. A left console device 11 is provided on the entrance / exit 8A side of the cab 8, i.e., on the left side of the operator's seat 10. A right console device 24 is provided on the opposite side, to the right of the operator's seat 10.

[0033] <Right console device> The right console device 24 includes a right operation lever 25, a right console cover 26, etc., and a right armrest 27 is attached to the rear end side of the right console frame. The right console device 24 has a switch box 67 in which a plurality of switches are provided, as shown in Fig. 6. Also, at a rear position of the right operation lever 25 on the right console device 24, there are arranged a wiper switching dial 80 for switching the rotation speed of the wipers (not shown), a numeric keypad switch 81 used for entering a PIN number to ensure security when starting up the hydraulic excavator 1, and the above-mentioned engine start switch 32.

[0034] The switch box 67 is divided into an operation mode area 67A which forms the rearmost area, an accessory area 67B which forms the area immediately preceding the operation mode area, and a detailed setting area 67C which forms the area immediately preceding the accessory area 67B.

[0035] The work mode area 67A is provided with the aforementioned engine control dial 125 for controlling the RPM of the engine 109, an auto idle dial 126 for maintaining the RPM of the engine 109 when the operating levers 25, 14 are not being operated, etc. The accessory area 67B is provided with a plurality of radio switches 138, 139 for operating a radio provided in the cab, etc. The detailed setting area 67C is provided with a rotary switch 92 for setting the details of various state quantities including the pressure of the hydraulic oil in the hydraulic system, etc.

[0036] <Left console device> As shown in FIGS. 5 and 7, the left console device 11 includes a left console frame 12, a left operation lever 14, a left console cover 15, and a shutoff device 19.

[0037] The left console frame 12 is attached to the left side of the driver's seat base 10A. The left console frame 12 has a base attachment part 12A that is attached to the driver's seat base 10A of the driver's seat 10, and a main frame part 12B that extends forward from the base attachment part 12A. A left armrest 13 is attached to the rear end side of the main frame part 12B, so that an operator sitting in the driver's seat 10 rests his / her left elbow on the left armrest 13. In addition, a left operation lever 14 and a shutoff device 19 are provided on the front end side of the main frame part 12B.

[0038] The left operating lever 14 is provided on the upper front end side of the main frame portion 12B that constitutes the left console frame 12. The left operating lever 14, together with a right operating lever 25 described below, is operated by the operator to control the rotational movement of the upper rotating body 3 and the movement of the work implement 4. The left operating lever 14 includes a pressure reducing pilot valve (not shown) and a lever portion 14A that extends upward from the pilot valve and is tilted in the front-rear and left-right directions by the operator.

[0039] The left console cover 15 is attached to the left console frame 12 and forms the outer shell of the left console unit 11. The left console cover 15 covers the left console frame 12, a pilot valve (not shown) of the left operation lever 14, a shut-off device 19, etc. The left console cover 15 is formed using an elastic resin material, and includes an upper cover 16, a side cover 17, and a shut-off cover 18.

[0040] The upper cover 16 covers the left console frame 12 and the like from above. The upper cover 16 is composed of a front cover portion 16A and a rear cover portion 16B. The front cover portion 16A is disposed in front of the left console frame 12 (main frame portion 12B) and covers the pilot valve of the left operating lever 14 and the like from above. The rear cover portion 16B rises downward from the rear end of the front cover portion 16A and extends rearward. The upper cover 16 is attached to the main frame portion 12B using bolts or the like (not shown). An upper surface 16C of the front cover portion 16A constituting the upper cover 16 is disposed at a position higher than an upper surface of the rear cover portion 16B and forms the upper surface of the left console device 11.

[0041] The side cover 17 is located below the upper cover 16 and covers the left console frame 12 and the like from the front-rear and left-right directions. The side cover 17 includes a front cover portion 17A disposed in front of the left console frame 12, an inner cover portion 17B extending rearward from the front cover portion 17A, and an outer cover portion 17C. The front cover portion 17A covers the left console frame 12, the pilot valve of the left operating lever 14, and the like from the front side. The inner cover portion 17B covers the left console frame 12, the pilot valve of the left operating lever 14, and the like from the right side (the driver's seat 10 side). The outer cover portion 17C covers the front portion of the left console frame 12 from the left side.

[0042] The shut-off cover 18 is attached to the left side surface of the side cover 17 (outer cover portion 17C). The shut-off cover 18 covers a rotation center portion 20A of the shut-off lever 20, a spring member 22, etc., from the left side, which will be described later. Note that Figures 8 and 9, which will be described later, show the shut-off cover 18 in a removed state.

[0043] <Shut-off device> Next, the shutoff device 19 according to the present embodiment will be described with reference to FIGS.

[0044] Of the left console unit 11 and the right console unit 24, the shutoff device 19 is provided in the left console unit 11, which is located on the door side of the driver's seat 10. The shutoff device 19 includes a shutoff lever 20, a spring member 22, a shutoff switch 23, the above-mentioned engine start preparation switch 30, etc. As described above, the shutoff lever 20 is pivotally displaced between the unlocked position shown in Fig. 8 and the locked position shown in Fig. 9. The shutoff device 19 functions to prohibit the operator from getting on and off the cab 8 when the shutoff lever 20 is in the unlocked position, and to allow the operator to get on and off when the shutoff lever 20 is in the locked position.

[0045] <Shut-off lever> The shutoff lever 20 is attached to a front portion of the main frame portion 12B constituting the left console frame 12 so as to be rotatable in the front-rear and up-down directions. The shutoff lever 20 is formed of a plate extending in the front-rear direction when in the unlocked position shown in Fig. 8. The shutoff lever 20 has a wide rotation center portion 20A located in the middle in the length direction, a narrow lever body portion 20B extending forward from the rotation center portion 20A when in the unlocked position, and an operating portion 20C extending rearward from the rotation center portion 20A when in the unlocked position.

[0046] The rotation center portion 20A is attached to the main frame portion 12B of the left console frame 12 via a support shaft 21 serving as a rotation fulcrum. The shutoff lever 20 is rotated and displaced about the support shaft 21 as a rotation fulcrum when an operator operates the operation portion 20C. The shutoff lever 20 is rotated and displaced between an unlocked position shown in Fig. 8 where the lever body portion 20B protrudes forward from the left console device 11, and a locked position shown in Fig. 9 where the lever body portion 20B extends downward.

[0047] When the shut-off lever 20 is in the unlocked position (position in FIG. 8 ), the lever body 20B prevents the operator from getting on and off the cab 8 by preventing the operator from moving. In the unlocked position, as described above, the operation of the left and right operating levers 14 and 25 is enabled, and the rotational movement of the upper rotating body 3 and the operation of the working device 4 are controlled in accordance with the operation of the left and right operating levers 14, 25. On the other hand, when the shut-off lever 20 is in the locked position (position in FIG. 9 ), the lever body 20B allows the operator to get on and off the cab 8 without preventing the operator from moving. In the locked position, as described above, the operation of the left and right operating levers 14, 25 is disabled, and the rotational movement of the upper rotating body 3 and the operation of the working device 4 are prohibited regardless of the operation of the left and right operating levers 14, 25.

[0048] A movable pin 20D is provided at the rotation center 20A at a position separated from the support shaft 21. The movable pin 20D is provided by welding or other means to protrude from the left side surface of the rotation center 20A and rotates around the support shaft 21 integrally with the shutoff lever 20. The movable pin 20D constitutes a one-end side mounting portion to which one end 22A of a spring member 22 described later is attached.

[0049] The operating part 20C is disposed on the opposite side of the lever body part 20B across the rotation center part 20A. The operating part 20C is operated by an operator to rotate and displace the shutoff lever 20 from the lock position to the unlock position, or from the unlock position to the lock position. A gripped part 20F having a shape that is more bulging than other parts of the operating part 20C is provided at the rear end of the operating part 20C when the shutoff lever 20 is in the unlock position. The gripped part 20F is a part that is gripped by one hand of the operator, i.e., the left hand. A recessed part 20E recessed toward the driver's seat 10 is provided on the left side of the gripped part 20F, and the operator can reliably operate the operating part 20C by placing his / her left hand on the recessed part 20E.

[0050] <Spring parts> The spring member 22 is formed by using, for example, a tension coil spring. One end 22A of the spring member 22 is attached to a movable pin 20D protruding from the rotation center 20A, and the other end 22B of the spring member 22 is attached to a fixed pin 12C protruding from the main frame portion 12B. The tensile force (spring force) of the spring member 22 always acts on the movable pin 20D protruding from the rotation center 20A. The shutoff lever 20 is always biased to the unlocked position (position in FIG. 8) or the locked position (position in FIG. 9) by the tensile force of the spring member 22. The spring member 22 switches between biasing the shutoff lever 20 toward either the unlocked position or the locked position, with the boundary being a position (switching position) where the operating portion 20C is lower than the upper surface 16C of the upper cover 16 of the left console device 11.

[0051] In this embodiment, when the center of the movable pin 20D is located on the straight line LL that connects the center of the fixed pin 12C and the center of the support shaft 21, the height position of the top of the operating part 20C coincides with the height position of the top surface 16C of the upper cover 16. When the shutoff lever 20 is between the locked position and the unlocked position, the position where the height position of the top of the operating part 20C coincides with the height position of the top surface 16C of the upper cover 16 as described above, i.e., the position where the operating part 20C is below the top surface 16C, is set as the switching position of the shutoff lever 20.

[0052] When the shutoff lever 20 is in the switching position, the tensile force of the spring member 22 is at a maximum value. When the shutoff lever 20 is displaced by a rotation angle θ2 from the switching position to the unlocked position (position in FIG. 8), the tensile force of the spring member 22 becomes smaller than the maximum value. When the shutoff lever 20 is displaced by a rotation angle θ3 from the switching position to the locked position (position in FIG. 9), the tensile force of the spring member 22 becomes even smaller. That is, the tensile force when the spring member 22 holds the shutoff lever 20 in the unlocked position is set to be larger than the tensile force when the spring member 22 holds the shutoff lever 20 in the locked position.

[0053] <Shut-off switch> The shutoff switch 23 is located near the rotation center 20A of the shutoff lever 20, and is attached to the main frame portion 12B of the left console frame 12. The shutoff switch 23 has a detection portion 23A that is pressed by the rotation center 20A when the shutoff lever 20 is rotated and displaced to the locked position. When the shutoff lever 20 is rotated to the locked position, the detection portion 23A is pressed by the rotation center 20A to detect the locked position. This makes the operations of the left operating lever 14 and the right operating lever 25 invalid, as described above. On the other hand, when the shutoff lever 20 is rotated to the unlocked position, the detection portion 23A is separated from the rotation center 20A to detect the unlocked position. This makes the operations of the left and right operating levers 14, 25 valid.

[0054] <Engine start preparation switch> A feature of this embodiment is that the engine start preparation switch 30 is provided on the shut-off lever 20, and in particular, that the engine start preparation switch 30 is provided at a specific portion of the shut-off lever 20. The specific portion is a portion where the operating direction of the engine start preparation switch 30 is a direction that prevents the shut-off lever 20 from rotating from the locked position toward the unlocked position. Specifically, as shown in Figures 10(a) and 10(b), the engine start preparation switch 30 is provided on the gripped portion 20F of the operating part 20C of the shutoff lever 20, at the side that is touched by the operator's left hand when rotating the shutoff lever toward the locked position, in other words, at the front side of the gripped portion 20F as seen by the operator sitting in the driver's seat when the shutoff lever is in the locked position. In particular, in this example, the engine start preparation switch 30 is provided on the gripped portion 20F, which is gripped by the operator when operating the shutoff lever 20, at a location where the palm of the operator's left hand comes into contact.

[0055] The engine start preparation switch 30 is a so-called momentary switch that is turned ON when manually pressed as shown in Fig. 10(c) and turned OFF when released (it is ON only while it is being pressed). This allows the operator to start the engine 109 only by continuing to press the engine start preparation switch 30 with the left hand and then pressing the engine start switch 32 with the right hand in that state. By providing the engine start preparation switch 30 in the above-mentioned position, even if the shutoff lever 20 rotates when the switch is operated, it rotates in the opposite direction to the unlocked position, that is, in the direction from the unlocked position to the locked position (hereinafter simply referred to as the "lock direction"), as shown by the black dashed arrow in Figure 10(c). Therefore, operation of the shutoff lever 20 in the unlocked direction is inhibited (rotation in the unlocked direction is not induced).

[0056] As another example, the engine start preparation switch 30 may be provided on the left side surface of the gripped portion 20F of the operating unit 20C at a location (specific location) that can be operated with the fingers of the left hand when the operator rotates it toward the locked position, as shown in Figures 11(a) and 11(b). By providing the engine start preparation switch 30 at this location, as shown in Fig. 11(c), the direction of depression when the switch is operated is along the axis of the rotation center portion 20A, so the shutoff lever 20 does not rotate. Therefore, as in the above, at least operation in the unlocking direction is inhibited (rotation in the unlocking direction is not induced).

[0057] <Effects of the embodiment> As described above, in the hydraulic excavator 1 of this embodiment, the rotatable shutoff lever 20 is provided in the operator's cab. When the shutoff lever 20 is rotated to the unlocked position, operation of the control levers 14, 25, etc. for operating the hydraulic actuators (the boom cylinder 103a, the arm cylinder 103b, the bucket cylinder 103c, etc.) is valid. As a result, the operator can operate the hydraulic excavator 1 as intended by operating the control levers 14, 25, etc. When the shutoff lever 20 is rotated to the lock position, the operation of the operating levers 14, 25, etc. is disabled, and the hydraulic excavator 1 will not operate even if the operating levers 14, 25, etc. are operated.

[0058] Moreover, the hydraulic excavator 1 of this embodiment is provided with an engine start preparation switch 30 and an engine start switch 32. When the operator operates both the engine start preparation switch 30 and the engine start switch 32, the starter motor 123 is driven via the engine control unit 102j, and the engine 109 is started. At this time, of these two switches, the engine start preparation switch 30 is provided on the shutoff lever 20. When the operator operates the engine start switch 32 to start the engine 109, the operator must always operate the engine start preparation switch 30. As a result, similar to a foot brake in an automobile, the operator can feel secure when starting the engine 109.

[0059] In particular, the engine start preparation switch 30 is provided at a specific portion of the hydraulic excavator 1, i.e., at a portion whose operation direction is a direction that prevents the shutoff lever 20 from rotating from the locked position to the unlocked position. Therefore, when the operator operates the engine start preparation switch 30 to start the engine 109, it is ensured that the shutoff lever 20 has not been operated to the unlocked position (=operated to the locked position). As a result, it is possible to reliably give the operator a sense of security when starting the engine 109.

[0060] In this embodiment, in particular, an engine start switch 32 for driving a starter motor is provided, and the engine start preparation switch 30 is a switch for preparing the start of the engine 109 in which the starter motor 123 is driven by the engine start switch 32. The engine start preparation switch 30 is provided in the above-mentioned specific portion on the same side as the shut-off lever 20 (the left side in the cab), while the engine start switch 32 is provided on the opposite side to the shut-off lever 20 (the right side in the cab). As a result, when starting the engine, the operator must operate both the engine start preparation switch 30 on the same side as the shutoff lever 20 and the engine start switch 32 on the opposite side to the shutoff lever 20. According to this embodiment, the engine 109 will not start unless the two switches 30, 32 located on both the left and right sides of the cab are simultaneously operated, which further enhances the sense of security of the operator.

[0061] In this embodiment, in particular, the shutoff lever 20 is provided with an operating portion 20C. The operation unit 20C is used when an operator rotates the shutoff lever 20 to the lock position. The engine start preparation switch 30 is provided on the operation unit 20C. This allows the operator to smoothly operate the engine start preparation switch 30 in conjunction with or in conjunction with the operation of rotating the shutoff lever 20 to the locked position using the operating unit 20C (see Figure 10(c) or Figure 11(c)). As a result, a specific configuration can be realized that ensures that the shutoff lever 20 is in the locked position when the engine start preparation switch 30 is operated.

[0062] Particularly in this embodiment, the shutoff lever 20 includes an operating portion 20C, a rotation center portion 20A, and a lever body portion 20B. An operator can switch the shutoff lever 20 from the unlocked position to the locked position by holding the gripped portion 20F of the operating portion 20C with one hand (the left hand in the above example) and rotating the entire shutoff lever 20 around the rotation center portion 20A. 10(a)-(c), the engine start preparation switch 30 is provided at a position that is abutted by the palm of the operator when the gripped portion 20F is gripped with one hand (left hand) as described above. This allows the operator to operate the engine start preparation switch 30 naturally and effortlessly when gripping the gripped portion 20F to switch it to the locked position. 11(a) to 11(c), the engine start preparation switch 30 is provided on the side surface of the gripped portion 20F at a position operable with the fingers of the one hand (left hand) when the gripped portion 20F is gripped by the operator as described above. This allows the operator to operate the engine start preparation switch 30 naturally and effortlessly when gripping the gripped portion 20F to switch it to the locked position.

[0063] On the other hand, as a comparative example, consider a case where the engine start preparation switch 30 is provided on a portion of the operation unit 20C that is touched by the left hand when the operator rotates the switch toward the unlocked position (in other words, the portion on the locking direction side) as shown in Figures 12(a), 12(b) or 13(a) and 13(b). In this case, if the shutoff lever 20 rotates when the switch is operated, it will rotate in the unlocking direction as shown by the dashed arrow in Figures 12(a) and 13(a) (rotation of the shutoff lever 20 in the unlocking direction is induced and not hindered). As shown in Figures 14(a) and 14(b), which are further comparative examples, if a push-type engine start preparation switch 30 is provided at the top of the operating unit 20C, it is possible that the shutoff lever 20 will be induced to rotate in the unlocking direction and will not be hindered, as described above.

[0064] 10(a)-(c) or 11(a)-(c), the present embodiment, unlike the comparative example, prevents the shutoff lever 20 from being operated in the unlocking direction. As a result, it is reliably guaranteed that the shutoff lever 20 is in the locked position when the engine start preparation switch 30 is operated.

[0065] In particular, in this embodiment, as described above with reference to FIG. 3, when the engine start switch 32 is operated in a state in which the engine 109 has already started, the engine is stopped by the engine control unit 102j. According to this embodiment, it is possible to prevent unexpected operation of the hydraulic excavator 1 due to control complications resulting from overlapping engine start operations.

[0066] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and technical concept of the present invention. Such modifications are described below. The same reference numerals are used to designate parts equivalent to those in the above-described embodiment, and descriptions thereof will be omitted or simplified as appropriate.

[0067] (1) When the engine start preparation switch is provided in a location other than the gripped part For example, Figs. 15(a) and 15(b) show an example in which the engine start preparation switch 30 is provided on the inner upper wall portion (specific portion) of a deeply formed recessed portion 20E. In this case, the engine start preparation switch 30 is turned on by being operated so as to be lifted substantially obliquely upward as indicated by the black arrow in FIG. 15(c) and FIG. 15(d).

[0068] Further, for example, Figs. 16(a) and 16(b) show a case where the engine start preparation switch 30 is provided at a position (specific position) facing the unlocking direction along a substantially horizontal direction on the top of the operation portion 20C. In this case, the engine start preparation switch 30 is turned on by being operated toward the lock direction along a substantially horizontal direction as indicated by the white arrow pointing leftward in FIG. 16(a).

[0069] Further, for example, Fig. 17(a) and Fig. 17(b) show a case where the engine start preparation switch 30 is provided at a portion (specific portion) facing the unlocking direction side on the upper surface of the operation unit 20C. In this case, the engine start preparation switch 30 is turned on by being operated toward the lock direction along a substantially horizontal direction as indicated by the white arrow pointing leftward in FIG. 16(a).

[0070] Further, for example, Figs. 18(a) and 18(b) show an example in which the engine start preparation switch 30 is provided on the inner lower wall portion (specific portion) of a deeply formed recessed portion 20E. In this case, the engine start preparation switch 30 is turned on by being operated substantially diagonally downward as shown by the outlined arrow in FIG. 18(b).

[0071] 15 to 18, even if the shutoff lever 20 rotates when the engine start preparation switch 30 is operated, the rotation will be in the locking direction, which is the opposite direction to the unlocking position, as shown by the black dashed arrows in Fig. 15(c), Fig. 16(a), Fig. 17(a), and Fig. 18(a). Therefore, even in these modified examples, operation of the shutoff lever 20 in the unlocking direction is inhibited (rotation in the unlocking direction is not induced). As a result, similarly to the above embodiment, it is ensured that the shutoff lever 20 has not been operated to the unlocked position, providing the operator with a sense of security.

[0072] (2) When the engine start preparation switch is provided at a location away from the shutoff lever 20 For example, in the example shown in Fig. 19(a), the shutoff lever 20 is configured to be rotatable in the opposite direction to the rotation from the locked position shown in Fig. 9 to the unlocked position shown in Fig. 8. The engine start preparation switch 30 is provided at a position away from the operating part 20C of the shutoff lever 20 in the locked position. In detail, the engine start preparation switch 30 is provided at a position (specific position) away from the forward side within the rotational trajectory R when the shutoff lever 20 rotates from the locked position shown in Fig. 19(a) in the opposite direction shown in Fig. 19(b).

[0073] In the example shown in Fig. 20(a), the engine start preparation switch 30 is provided at a position away from the lever body 20B of the shutoff lever 20 in the locked position. In detail, the engine start preparation switch 30 is provided at a position away from the lever body 20B in the locked position. In particular, the engine start preparation switch 30 is provided at a position (specific position) away from the lever body 20B in the locked position.

[0074] In the above two configurations, when an operator wishes to start the engine 109, it is necessary to operate the operating part 20C and rotate the shutoff lever 20 in the direction opposite to the unlocked position. By this rotation operation, the operator can abut the operating part 20C or the lever body part 20B of the shutoff lever 20 against the engine start preparation switch 30 located within the rotational orbit R, and operate the engine start preparation switch 30. Therefore, in these two modified examples, the operation of the shutoff lever 20 in the unlocking direction is inhibited (rotation in the unlocking direction is not induced). As a result, as in the above embodiment, it is guaranteed that the shutoff lever 20 is not operated to the unlocking position when the engine start preparation switch 30 is operated, which gives the operator a sense of security.

[0075] (3) In the case where the function of the engine start switch 32 is transferred to the engine start preparation switch 30 and integrated into one switch That is, in this modified example, the engine start switch 32 in the right console device 24 shown in Fig. 5 is omitted. Then, a single engine start preparation switch 31 (not shown) that combines the functions of the engine start preparation switch 30 and the engine start switch 32 is provided at the specific location on the operation part 20C of the shutoff lever 20 or in the vicinity thereof (including a location distant from the operation part 20C).

[0076] <Engine start control by the engine control unit> In this modification, the operator is required to operate the engine start preparation switch 31 when starting the engine 109. The contents of the control logic incorporated in the engine control unit 102j in this modification are shown in FIG. 21, which corresponds to FIG. 4 above.

[0077] As shown in Fig. 21, for example, a state in which the engine start preparation switch 31 is not operated is a so-called KEY-OFF state. When the engine start preparation switch 31 is operated for a relatively long time from this state (a so-called long press; the same applies below), the state transitions to a so-called KEY-ON state. When the engine start preparation switch 31 is further operated for a relatively long time in this state, an engine control command is output from the engine control unit 102j to the starter motor control unit 124, and the engine 109 is started.

[0078] Furthermore, when the engine start preparation switch 31 is operated for a relatively short time (a so-called short press; the same applies below), the state transitions from the KEY-OFF state to a so-called ACC state in which electricity is supplied to the electrical components. When the engine start preparation switch 31 is further operated in this ACC state, the state transitions to the KEY-ON state.

[0079] In addition, if the engine start preparation switch 31 is further operated for a relatively short time in the above-mentioned KEY-ON state, or if the engine start preparation switch 31 is further operated in the engine start state, the engine 109 is stopped based on an engine control command from the engine control unit 102j to the ECU 113.

[0080] In this modification, the engine start preparation switch 31 can be configured as a so-called momentary switch, similar to the above-described engine start preparation switch 30. This allows the operator to start the engine 109 only when the operator presses the engine start preparation switch 31 with the left hand for a comparatively long period of time. By providing the engine start preparation switch 31 at the same position (specific portion) as the engine start preparation switch 30 described above, as described above, when the engine start preparation switch 31 is operated, the shutoff lever 20 does not rotate, or even if it rotates, it rotates in the lock direction, which is the opposite direction to the unlock position. Therefore, the operation of the shutoff lever 20 in the unlock direction is inhibited (rotation in the unlock direction is not induced). That is, in this modified example, as described above, when the operator operates the engine start preparation switch 31 to start the engine 109, it is guaranteed that the shutoff lever 20 is not operated to the unlock position (=operated to the lock position). As a result, like the foot brake in an automobile, a sense of security can be given to the operator when starting the engine 109.

[0081] (4)Other In the embodiment, the hydraulic excavator 1 has been taken as an example of the construction machine, but the present invention is not limited to this and can be widely applied to other construction machines, such as hydraulic cranes and wheel loaders, that are equipped with actuators driven by pressure oil from a hydraulic pump driven by an engine.

[0082] <About shape, values, structure, etc.> Concerning the components illustrated in the embodiments and drawings, the shapes, values, and interrelationships between multiple components can be modified and improved as desired within the scope of the technical concept of the present invention. For example, the term "same" in the above description does not have a strict meaning. In other words, "same" means "substantially equal" while allowing for design and manufacturing tolerances and errors. Moreover, the arrows shown in FIG. 3 and other figures show an example of the flow of signals, and do not limit the direction of the signal flow. In addition to the above, the methods according to the above embodiments and their modifications may be used in appropriate combination. Although not specifically illustrated, the present invention can be implemented with various modifications without departing from the spirit and scope of the present invention.

[0083] <About the problem to be solved and the effects of the invention> Furthermore, the problems to be solved by the invention and the effects of the invention are not limited to those described above. In other words, the present invention may solve problems or achieve effects that are not described above, or may solve only some of the problems or achieve only some of the effects that are described. [Explanation of symbols]

[0084] 1. Hydraulic excavator (construction machinery) 14 Left operation lever 20 Shut-off lever 20A Rotation center 20B Lever body 20C Control unit 20F Grasped part 25 Right operation lever 30 Engine start preparation switch 31 Engine start preparation switch 32 Engine start switch (starter motor drive switch) 101a Boom 101b Arm 101c Bucket 102j Engine control unit 103a Boom cylinder (hydraulic actuator) 103b Arm cylinder (hydraulic actuator) 103c Bucket cylinder (hydraulic actuator) 103d Swing motor (hydraulic actuator) 103e Travel motor (hydraulic actuator) 103f Travel motor (hydraulic actuator) 106 Hydraulic Pump 107 Pilot oil pump 109 Engine 123 Starter motor R rotation orbit

Claims

1. The engine as a power source, a hydraulic pump and a pilot oil pump driven by the engine; A plurality of hydraulic actuators each having the hydraulic pump as a drive source; a plurality of operation levers provided in a cab for operating the plurality of hydraulic actuators using pilot pressure oil from the pilot oil pump; a shutoff lever provided in the driver's cab and rotatable between a lock position that disables operation of the operation lever and an unlock position that enables operation of the operation lever; a starter motor drive switch for driving the starter motor; an engine control unit that drives the starter motor by the starter motor drive switch to start the engine; In a construction machine equipped with an engine start preparation switch for preparing to start the engine by the starter motor drive switch; The engine start preparation switch is disposed on the shutoff lever. A construction machine characterized by:

2. 2. The construction machine according to claim 1, The engine start preparation switch is The operating direction of the lock lever is a direction that prevents the shutoff lever from rotating from the lock position to the unlock position. A construction machine characterized by:

3. 2. The construction machine according to claim 1, The starter motor drive switch is The shutoff lever is provided on the opposite side of the left and right sides of the cab. A construction machine characterized by:

4. 2. The construction machine according to claim 1, The engine start preparation switch is The shutoff lever is provided at or near an operating portion for rotating the shutoff lever toward the lock position. A construction machine characterized by:

5. 2. The construction machine according to claim 1, The shutoff lever is A rotation center portion located at a middle portion in a longitudinal direction including the rotation center; a lever body portion extending forward from the rotation center portion when the lever is in the unlocked position; an operation portion extending rearward from the rotation center portion when the lock lever is in the unlocked position; having The operation unit includes: A gripping portion has a shape that is larger than other portions and is gripped by one hand of an operator, The engine start preparation switch is The gripping portion is provided at a portion where the palm of the one hand comes into contact. A construction machine characterized by:

6. 2. The construction machine according to claim 1, The shutoff lever is A rotation center portion located at a middle portion in a longitudinal direction including the rotation center; a lever body portion extending forward from the rotation center portion when the lever is in the unlocked position; an operation portion extending rearward from the rotation center portion when the lock lever is in the unlocked position; having The operation unit includes: A gripping portion has a shape that is larger than other portions and is gripped by one hand of an operator, The engine start preparation switch is The gripping portion is provided at a portion of a side surface thereof that can be operated by the fingers of the one hand. A construction machine characterized by:

7. 2. The construction machine according to claim 1, The shutoff lever is A rotation center portion located at a middle portion in a longitudinal direction including the rotation center; a lever body portion extending forward from the rotation center portion when the lever is in the unlocked position; an operation portion extending rearward from the rotation center portion when the lock lever is in the unlocked position; having The locking mechanism is configured to be rotatable in a direction opposite to the direction of rotation from the locking position to the unlocking position, The engine start preparation switch is The shutoff lever is provided at a location separated from the shutoff lever and located within a rotational trajectory when the shutoff lever rotates in the opposite direction from the lock position. A construction machine characterized by:

8. 2. The construction machine according to claim 1, The engine control unit includes: A construction machine characterized in that, when the starter motor drive switch is operated while the engine is started, the engine is stopped.

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