JP2000280940A - Detector for carburetor tilt cylinder extension and carburetor tilt controller using thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detector for cylinder rod extension capable of surely detecting the completion of the carburetor tilting-up of a large vehicle by a simple structure. SOLUTION: The extension detector 70 of a carburetor tilt cylinder 40 is provided with a stroke detecting plate 71 fixed to a cylinder rod 43 and moved following its elongation/contraction, a switch push lever 73 rotatably attached to a cylinder main body 40A to be abutted on the plate 71, a return spring for energizing it, and a cylinder extension detecting switch 75. The switch push lever 73 turns the cylinder extension detecting switch SW 75 ON/OFF according to the abutting or no abutting of the cantilever 73B of the plate 71 on the plate 71.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extension detector for a cab tilt cylinder and a cab tilt control device using the same.

[0002]

2. Description of the Related Art For large vehicles such as trucks, the cab is tilted during the vehicle inspection work, thereby increasing the work efficiency. A conventional cab tilt, as shown in FIG.
The cab 2 of the vehicle 1 is moved to the chassis 3 with the tilt center P
This is done by rotating about.

[0003] The rotation of the cab 2 is performed by a cab tilt cylinder 4 having one end connected to the chassis 3 and the other end connected to the cab 2. That is, the cab tilt cylinder 4 is connected to a hydraulic pump (electric pump) 5 connected thereto.
Is operated to apply a hydraulic pressure of a certain level or more to the cab tilt cylinder 4, whereby the cylinder rod 4A expands, and the cab 2 is tilted up (ascended). Cab 2
On the contrary, the oil pressure in the cab tilt cylinder 4 may be reduced to a certain level or less. This operation is also performed by the hydraulic pump 5.

Switching of the cab 2 between tilt-up (up) and tilt-down (down) by the cab tilt cylinder 4 is performed by operating a switching lever 5A of the hydraulic pump 5. Then, in this state, when the start button 5B provided on the hydraulic pump 5 is pressed, the ascent / descent of the cab 2 is started.

[0005] The vehicle 1 is provided with a tilt lock mechanism 6. The tilt lock mechanism 6 includes a lock hook 6A provided on the chassis 3 side and a pin 6B on the cab 2 side locked by the lock hook 6A. In the tilt lock mechanism 6, locking / unlocking is performed by operating a lock lever 6C provided on the chassis 3 side and prohibiting rotation of the locking hook 6A.

The cab tilt cylinder 4 is provided with a cylinder lock mechanism 7 so that the cab 2 (shown by a solid line in FIG. 11) does not descend. As shown in FIG. 12, the cylinder lock mechanism 7 includes a saw-tooth stopper lever 7A that moves as the cylinder rod 4A expands / contracts, and a lock lever 7B that fits the stopper lever 7A.
And a lock release link mechanism 7C and a wire 7D connected thereto.

In this cylinder lock mechanism 7, a lock lever 7B is moved by a return spring (not shown) to a distal end 7B thereof.
1 are urged toward the teeth 7A1... Of the serrated stopper lever 7A, and when these are fitted together, locking is performed. Thus, when the cylinder rod 4A of the cab tilt cylinder 4 is extended, the locking by the cylinder lock mechanism 7 is not performed, and only when the cylinder rod 4A contracts, the tip 7B1 of the lock lever 7B is brought into contact with the teeth 7A1 of the sawtooth stopper lever 7A. Fit. This inhibits the cab 2 from lowering during tilt.

The release of the cylinder lock mechanism 7 (the operation of removing the tip 7B1 from the teeth 7A1) is performed by operating a release switch 8 (FIG. 11) connected to a lock release wire 7D. The lock lever 7B has a cylinder extension detection switch SW13 for detecting a locked state (a lowering prohibited state) and a cylinder contraction switch SW14 for indicating a state in which the cylinder rod 4A is completely contracted.
Is provided.

[0009]

However, in recent large vehicles, the hydraulic pump 5 is increased in size and the cab 2 is tilted up until the center of gravity of the cab 2 is located forward of the tilt center P, thereby increasing the cab. There is no longer a danger of the 2 dropping by mistake. Therefore, if the cab tilt cylinder 4 provided with the above-described conventional cylinder lock mechanism 7 and various devices for driving the same (such as the hydraulic pump 5) are used as they are, the cylinder cab 2 is tilted up / down each time. Release switch 8 for lock mechanism 7
Must be unlocked by the operation of.

In particular, whether the cab 2 has been tilted up or not is determined by the lock lever 7 of the cylinder lock mechanism 7.
B is detected by the cylinder extension detection switch SW13 which is turned on / off by the rotation of B. Since the on / off of the cylinder extension detection switch SW13 is interlocked with the release switch 8 which is manually operated, the tilt-up is completed. It cannot be detected only by the actual extension state of the cylinder rod 4A.

If the detection of whether or not the tilt-up is completed is related to the manual operation of the release switch 8, the automatic control of the tilt-up / tilt-down of the cab 2 cannot be performed. There is. The present invention has been made in view of such circumstances, and a first object of the present invention is to provide a cylinder rod extension detector capable of reliably detecting the completion of tilt-up by a cab tilt cylinder with a simple configuration. is there.

A second object of the present invention is to provide a cab tilt control apparatus which can easily and safely perform automatic tilt-up / tilt-down control using the extension detector of the cab tilt cylinder. It is to provide.

[0013]

In order to achieve the above object, an extension detector for a cab tilt cylinder according to claim 1 is provided so as to be rotatable on a plate moving with extension / retraction of a cylinder rod and a cylinder body. A rotating lever attached to be in contact with the plate and rotating in accordance with the shape of the plate; biasing means for biasing the rotating lever toward the plate; and rotation of the rotating lever. And a switch that operates according to the amount.

According to a second aspect of the present invention, there is provided a cab tilt control device, comprising: an extension detector according to the first aspect; a cab tilt cylinder for raising / lowering the cab in a tilt direction;
A drive unit for causing the cab tilt cylinder to perform an extension / contraction operation, and a control circuit for outputting a drive signal to the drive unit, wherein the control circuit starts the extension / contraction operation of the cab tilt cylinder by the drive unit. A first switch interlocked with a button, a second switch that switches depending on whether the operation of the cab tilt cylinder by the driving unit is in the extension direction or the contraction direction, and a third switch provided in the extension detector And the fourth is switched in accordance with the contracted state of the cylinder rod of the cab tilt cylinder.
The control circuit further comprises: a control unit that controls the operation of the cab tilt cylinder in the extension direction by the second switch; and that the cylinder rod is not extended to a target stroke by the third switch. thing,
And outputting a drive signal to the drive unit on condition that the start is started by the first switch.
That the operation of the cab tilt cylinder is in the contraction direction by the second switch, and that the cylinder rod is not contracted below a certain value by the fourth switch,
Further, a driving signal is output to the driving means on condition that starting is started by the first switch.

According to a third aspect of the present invention, the drive means controls the cab tilt cylinder to rotate the cab until the center of gravity of the cab is located forward of a tilt center. .

(Operation) According to the first aspect of the present invention, the extension state of the cab tilt cylinder can be directly detected according to the actual extension of the cylinder rod. Further, according to the second aspect of the present invention, the tilt up / tilt down of the cab can be automatically controlled by pressing the start button.

Further, according to the third aspect of the present invention, there is no possibility that the cab which has been tilted up may fall down erroneously, and the load on the cab tilt cylinder and the driving means can be reduced.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. This embodiment corresponds to claims 1 to 3.

First, a vehicle 1 to which the extension detector for a cab tilt cylinder and the cab tilt control device of the present invention are applied.
The structure of 0 and its tilt operation will be described. FIG.
As shown in (a), the cab 12 of the vehicle 10 rotates about the tilt center P with respect to the chassis 13. A cab tilt cylinder 40 for tilting up (up) / tilting down (down) the cab 12 is disposed between the cab 12 and the chassis 13.

The cab tilt cylinder 40 has a mounting portion 41 at one end connected to the chassis 13 and a mounting portion 4 at the other end.
2 is connected to the cab 12 side. An electric hydraulic pump (drive means) 50 is connected to the cab tilt cylinder 40 via an oil pipe 51, and a first hydraulic pressure equal to or higher than a predetermined value / a second hydraulic pressure equal to or lower than a predetermined value is selected from the hydraulic pump 50. Specifically, the cylinder rod 43 is provided inside the cylinder main body 40A so that the cylinder rod 43 expands / contracts.

The switching between the first hydraulic pressure and the second hydraulic pressure is performed by operating the switching lever 52 of the hydraulic pump 50. The hydraulic pump 50 is provided with a start button 5
Pressing 3 starts its operation. Further, the vehicle 1 is provided with a tilt lock mechanism 60. The tilt lock mechanism 60 includes a lock hook 61 provided on the chassis 13 side, a pin 62 on the cab 12 locked by the lock hook 61, and a lock lever 63 on the chassis 3 side.
The lock lever 63 prohibits / permits rotation of the lock hook 61.

In the normal state shown in FIG. 1A (for example, during running), the lock lever 63 is in the tilt lock position, and the rotation of the lock hook 61 is prohibited. When the rotation of the locking hook 61 is prohibited, the tilt up of the cab 12 is prohibited while the pin 62 remains locked. When tilting up from this state, first, the lock lever 63 is released. When the lock lever 63 rotates in the direction shown by the arrow in FIG. 1A, the lock hook 61 also rotates in the direction shown by the arrow in FIG. 1A, and the pin 62 on the cab 12 side is released.

In this state, the start button 53 of the hydraulic pump 50 is
Is pressed, the cylinder rod 43 of the cab tilt cylinder 40 is extended, and the cab 12 rotates about the cab center P as shown by the arrow in FIG. 1B (tilt up). In addition, in the vehicle 10, the cab 1
2 is rotated until the center of gravity G is at least forward of the tilt center P.

In the vehicle 10 configured as described above, a start switch SW1 (first switch) for detecting a start state of the hydraulic pump 50 (pressing of the start button 53), a switching lever 5
2, a bypass switch SW2 (second switch) that switches in accordance with the ascending / descending direction (tilt up / tilt down) of the cylinder rod 4 of the cab tilt cylinder 40
Cylinder extension detection switch SW for detecting the extension state of 3
3 (third switch), a cylinder contraction detection switch SW4 (fourth switch) for detecting the contraction state of the cylinder rod 43, and a tilt lock switch SW5 (fifth switch) for detecting the tilt lock state based on the position of the lock lever 63.
Switch) is arranged.

As will be described in detail later, a drive signal is output from the cab tilt control device 100 (FIG. 8) in accordance with the on / off of the switches SW1 to SW5, and the hydraulic pump 50 is driven. Elongation / contraction takes place. Here, the configuration of the cab tilt cylinder 40 for tilting the cab 12 and the extension detector 70 and the contraction detector 80 provided therein will be described with reference to FIGS.
This will be described with reference to FIG. The extension detector 70 is provided with the cylinder extension detection switch SW3, and the contraction detector 80 is provided with the cylinder contraction detection switch SW4.

As shown in FIG. 2, the cab tilt cylinder 40 has a mounting portion 41 formed at one end of a cylinder body 40A. From the cylinder body 40A, a cylinder rod 43 that expands / contracts according to the hydraulic pressure supplied to the inside thereof extends. A mounting portion 42 is provided at a distal end portion 43a of the cylinder rod 43 via a link mechanism (not shown).

The cylinder body 40A is provided with an extension detector 70 and a contraction detector 80. The extension detector 70 is, as shown in FIGS. 2 to 4, fixed to the cylinder rod 43 by the connecting portion 44 and moves along with the extension / contraction of the stroke detection plate (plate) 71.
A mounting portion 72 fixed to the cylinder body 40A side,
A switch push lever (rotary lever) that is rotatably mounted on the mounting portion 72 about a rotary shaft 73A.
73, a return spring (biasing means) 74 for urging the cantilever portion 73B of the switch push lever 73 in the direction of contacting the stroke detection plate 71, and the rod 75A can contact the pressing portion 73C of the switch push lever 73. Extension detection switch 75 (SW
3).

In the thus constructed extension detector 70, when the cylinder rod 43 is in a contracted state (FIG. 2), the cantilever portion 73B is pressed against the wall surface of the stroke detection plate 71. Return spring 74
The rotation of the switch push lever 73 due to the urging is restricted by the stroke detection plate 71. When the rotation is limited in this manner, the pressing portion 73C
Does not push back the rod 75A of the cylinder extension detection switch 75 (SW3) (SW3 is ON).

From this state, when the cylinder rod 43 expands and the stroke detection plate 71 moves along with the stroke and reaches a desired stroke (FIG. 5), the cantilever portion 7 is moved.
3B is disengaged from the stroke detection plate 71 that has been in contact therewith (FIG. 6), and the switch push lever 73 is disengaged.
Is rotated about the rotating shaft 73A by the biasing force of the return spring 74 (from the broken line to the solid line in FIG. 6), and the pressing portion 73C pushes back the rod 75A of the cylinder extension detection switch 75 (SW3) (SW3). Is off).

The switch push lever 73 is configured to rotate when the cantilever portion 73B is disengaged from the end of the stroke detection plate 71, thereby turning off the cylinder extension detection switch 85, but is not limited thereto. For example, the shape of the stroke detection plate 71 in the portion that comes into contact with the cantilever portion 73B is changed in accordance with the movement of the stroke detection plate 71 so that the switch push lever 73 rotates appropriately as the cylinder rod 43 expands. Alternatively, the switch push lever 73 may be rotated with the movement of the stroke detection plate 71.

In this case, when the switch push lever 73 rotates by a predetermined rotation amount, the pressing portion 73C may turn on / off the cylinder extension detection switch 75. On the other hand, as shown in FIG. 2, the shrinkage detector 80 provided on the cylinder body 40 </ b> A has an L-shaped fitting 81 fixed to the cylinder rod 43 side, and the rod 85 </ b> A can contact the L-shaped fitting 81. And a cylinder shrinkage detection switch 85 (SW4) disposed at

In the contraction detector 80 thus configured, when the cylinder rod 43 is completely contracted (FIG. 2), the L-shaped bracket 81 is set to the cylinder contraction detection switch 8.
The 5 (SW4) rod 85A is pushed back (SW4 is in a first connection state described later). Then, when the cylinder rod 43 expands and the L-shaped bracket 81 separates from the rod 85A of the cylinder contraction detection switch 85 (SW4), a second connection state described later is established (FIG. 5).

Next, the structure of a hydraulic pump 50 for selectively supplying the first hydraulic pressure / second hydraulic pressure to the cab tilt cylinder 40 will be described with reference to FIG. Hydraulic pump 50
Has an oil tank 54, a pump body 55, and a motor 56 as main components. Pump body 55
Is provided with an operation section 57, to which the switching lever 5 is attached.
2, a start button 53, and a bypass switch SW2 for detecting a switching direction (tilt up / tilt down) of the switching lever 52 are arranged.

Here, the switching lever 52 determines which of the first hydraulic pressure for expanding the cylinder rod 43 and the second hydraulic pressure for contracting the cylinder rod 43 is generated when the motor 56 is operating. To decide. In this embodiment, the start button 53 also functions as the start switch SW1. Further, the oil pipe 51 shown in FIG. 1 is connected to the pump body 55.
Does not appear in.)

The hydraulic pump 50 thus configured is
Under a certain condition (for example, when the tilt lock is released), the switching lever 5
2 is switched between tilt-up and tilt-down, and when the start button 53 is pressed, the motor 56 starts operating. Then, one of the first and second hydraulic pressures is supplied from the hydraulic pump 50 to the cab-lift cylinder 40.

Next, the above-mentioned five switches SW1 to SW
The configuration of the cab tilt control device 100 using W5 will be described with reference to FIGS. As shown in FIG. 8, the cab tilt control device 100 includes a hydraulic pump 50 (motor 56), a relay switch 101 for turning on / off the motor 56, a relay switch 101 and a fuse 1
8, a battery 103 that supplies a power supply voltage to the motor 56 via a motor 02, a switch circuit unit (control circuit) 110 that controls on / off of a relay switch 101, a cab-side battery 104, and a cabtilt cylinder 40 (FIG. Not appearing).

In the cab tilt control device 100 configured as described above, the switches SW1 to SW5 are turned on / off.
In accordance with the OFF state, electrical connection / disconnection between the cab-side battery 104 and the coil of the relay switch 101 is performed, and the motor 56 operates accordingly. In addition, the switch circuit unit 110 includes the five switches SW1 to S
W5 is connected, and a warning buzzer (warning means) 111 for warning a tilt operation is connected between the start switch SW1 and the cylinder contraction detection switch SW4.

Here, ON / OFF of the switches SW1 to SW5 connected to the switch circuit unit 110 will be described. The start switch SW1 is turned on when the operator presses the start button 53 to perform a tilt operation (tilt up / tilt up), and is turned off otherwise. The bypass switch SW2 is turned off when the switching lever 52 is switched in the ascending direction (tilt up) (FIG. 7A).
When switching to the descending direction (tilt down) (Fig. 7
(B)) Turns on.

The cylinder extension detection switch SW3 is normally turned on, and is turned off when the cylinder rod 43 of the cab tilt cylinder 40 is extended beyond a certain value (for example, at the time of the maximum extension at which a target stroke is reached). When the cylinder rod 43 is completely contracted, the contacts N0 and N1 are connected (first connection state). When the cylinder rod 43 is slightly extended, the contact SW0 is connected to the contact N0. N2 is connected (second connection state).

The tilt lock switch SW5 is turned off when the tilt lock is performed by the tilt lock mechanism 60 and turned on when the lock is released. Next, the operation control of the motor 56 by the cab tilt control device 100 (the cylinder rod 4 of the cab tilt cylinder 40) is performed.
3 will be described focusing on the connection states of the switches SW1 to SW5 in the switch circuit unit 110.

The state shown in FIG. 8 shows the cab tilt control device 100 in a normal state. In normal times (FIG. 1A), since the tilt lock is performed by the tilt lock mechanism 60, the tilt lock switch SW5 is off.
Further, since the cylinder rod 43 of the cab tilt cylinder 40 is completely contracted (FIG. 2), the cylinder extension detection switch SW3 is turned on, and the cylinder contraction detection switch SW4 is turned on.
Is in the first connection state (contact points N0 and N1 are connected). At this time, the start button 53 is not pressed, the start switch SW1 is turned off, and the bypass switch SW2 is kept on. At this time, the relay switch 101 is not turned on, and neither the motor 56 nor the warning buzzer 111 is operated.

The case of performing the tilt-up from this state (FIG. 8) will be described with reference to FIGS. 9 (a) to 9 (e). When performing tilt-up, first, as shown in FIG. 9A, the tilt lock is released, and the tilt lock switch SW5 is turned on. At this time, the warning buzzer 111 operates to notify a tilt operation.

In this state, when the switching lever 52 is rotated to the tilt-up (up) side, the bypass switch SW2
Is turned off (FIG. 9B). At this time warning buzzer 11
1 continues to operate. When the start button 53 is pressed in this state, the start switch SW1 is turned on (FIG. 9).
(C)), a current flows as shown by an arrow in the figure, the relay switch 101 is turned on, and the motor 56 starts operating. At this time, the warning buzzer 111 remains activated.

When the first hydraulic pressure is supplied to the cab tilt cylinder 40 by the operation of the motor 56 (at this time, the switching lever 52 is tilted up), the cylinder rod 43
Starts expanding, and the cylinder contraction detection switch SW4 switches from the first connection state (the contacts N0 and N1 are connected) to the second connection state (the contacts N0 and N2 are connected) (FIG. 9).
(D)). At this time, the warning buzzer 111 remains activated.

Further, when the cylinder rod 43 is extended by the operation of the motor 56 and reaches a certain extended state (maximum extended position: FIG. 5), the cylinder extension detecting switch SW3
Is turned off (FIG. 9E). At this time, the electrical connection between the cab-side battery 104 and the coil of the relay switch 101 is disconnected, and the motor 56 stops operating again. At this time, the warning buzzer 111 also becomes inactive (tilt up is completed). Usually, when the warning buzzer 111 stops sounding, the operator recognizes that the tilt-up is completed and stops pressing the start button 53.

Next, the case where the cab 12 is tilted down from the state where the tilt up is completed, will be described with reference to FIG.
This will be described with reference to (a) to (e). When performing tilt-down, first, the switching lever 52 is turned to the tilt-down (down) side, and the bypass switch SW2 is turned on as shown in FIG. At this time, the warning buzzer 111 starts operating to notify the start of the tilt-down operation.

In this state, when the operator presses the start button 53 again, the start switch SW1 is turned on (FIG. 10).
(B)), a current flows as indicated by an arrow in the figure, the relay switch 101 is turned on, and the motor 56 starts operating. At this time, the warning buzzer 111 remains activated. The current flows at this time because the bypass switch SW2 is already turned on before the start switch SW1 is turned on (bypass function).
The cab side battery 104 and the start switch SW1 are electrically connected by the cylinder contraction detection switch SW4 in the second connection state (contact points N0 and N2 are connected) with W2.

When the hydraulic pressure to the cab tilt cylinder 40 becomes the second hydraulic pressure by the operation of the motor 56 (at this time, the switching lever 52 is in the tilt down position), the cylinder rod 43 starts to contract. When the cylinder rod 43 contracts even slightly, the cylinder extension detection switch SW3 is turned on (FIG. 10C). At this time, warning buzzer 111
Remains active.

Further, when the cylinder rod 43 contracts due to the operation of the motor 56 and the pin 62 on the cab 12 engages with the locking hook 61 to be locked, the tilt lock switch SW5 is turned off again (FIG. 10
(D)). At this time, the warning buzzer 111 remains activated. When the motor 56 continues to operate, the cylinder rod 43 is completely contracted, and the cylinder contraction detection switch SW4 is changed from the second connection state (contacts N0 and N2 are connected) to the first connection state (contacts N0 and N1 are connected). Return to connection (Figure 1)
0 (e)). At this time, the electrical connection between the cab-side battery 104 and the coil of the relay switch 101 is disconnected, and the motor 56 stops operating again. At this time warning buzzer 11
1 also becomes inactive (tilt down completed). When the warning buzzer 111 stops sounding, the operator recognizes that the tilt-down operation has been completed, and stops pressing the start button 53.

[0050]

According to the first aspect of the present invention described above,
Since the extension state of the cab tilt cylinder can be directly detected in accordance with the actual extension of the cylinder rod, the completion of tilt-up by the cab tilt cylinder can be reliably detected with a simple configuration.

According to the second and third aspects of the present invention,
The cab tilt up / down is controlled according to the extension state of the cylinder rod detected by the extension detector of the cab tilt cylinder, the contraction state of the cylinder rod, the operation state of the start button, and the like, which are detected by other switches. Tilt down can be automatically controlled easily and safely.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a structure of a vehicle 10 to which a cab-tilt cylinder extension detector and a cab-lift control device of the present invention are applied.

FIG. 2 is a side view showing a configuration of the cab tilt cylinder 40.

3 is an enlarged side view showing an extension detector 70 of the cab tilt cylinder 40. FIG.

FIG. 4 is an enlarged plan view showing an extension detector 70 of the cab tilt cylinder 40.

FIG. 5 is a side view showing the cab tilt cylinder 40 with the cylinder rod 43 extended.

FIG. 6 is an enlarged side view showing the extension detector 70 when the cylinder rod 43 is extended.

FIG. 7 is a side view showing the configuration of the hydraulic pump 50.

FIG. 8 is a circuit diagram showing a configuration of the cab tilt control device 100.

FIG. 9 is a circuit diagram showing a state of switches SW1 to SW5 of the switch circuit unit 110 at the time of tilt-up.

FIG. 10 is a circuit diagram showing a state of switches SW1 to SW5 of the switch circuit unit 110 during tilt down.

FIG. 11 is an explanatory diagram showing tilt-up of a cab 2 in a conventional vehicle 1.

FIG. 12 is an explanatory view showing a cylinder lock mechanism provided in a conventional cab tilt cylinder 4.

[Explanation of symbols]

12 Cab 13 Chassis 40 Cabylt cylinder 50 Hydraulic pump (drive means) 52 Switching lever 53 Start button 53 56 Motor 70 Extension detector 71 Stroke detection plate (plate) 73 Switch push lever (rotary lever) 74 Return spring (biasing means) 75 cylinder extension detection switch (SW3: third switch) 80 contraction detector 85 cylinder contraction detection switch (SW4: fourth switch) 100 cab tilt control circuit 101 relay switch 110 switch circuit unit SW1 start switch (first switch) SW2 Bypass switch (second switch) SW5 Tilt lock switch (fifth switch)

Claims (3)

[Claims] 1. An extension detector for a cab tilt cylinder that rotates a cab in a tilt direction, the extension detector comprising: a plate that moves in accordance with extension / contraction of a cylinder rod; A rotating lever attached to be in contact with the plate and rotating according to the shape of the plate; a biasing unit for biasing the rotating lever toward the plate; and a rotation amount of the rotating lever. And a switch that operates in response to the signal. 2. The extension detector according to claim 1, a cab tilt cylinder for raising / lowering the cab in a tilt direction, a driving unit for causing the cab tilt cylinder to perform an extension / contraction operation, and a driving unit for driving the cab. A control circuit for outputting a signal, the control circuit comprising: a first switch interlocked with a start button for starting an extension / retraction operation of the cabtilt cylinder by the driving unit; The direction is switched depending on whether the direction or the contraction direction is the second.
, A third switch provided in the extension detector, and a fourth switch that is switched in accordance with a contracted state of a cylinder rod of the cab tilt cylinder, wherein the operation of the cab tilt cylinder is performed by the second switch. Is driven in the extension direction, the cylinder switch is not extended to a target stroke by the third switch, and the activation is started by the first switch. Outputting a signal, that the operation of the cab tilt cylinder is in the contraction direction by the second switch, that the cylinder rod is not contracted below a certain value by the fourth switch,
And a drive signal is output to the drive means on condition that start-up is started by the first switch. 3. The cab tilt control device according to claim 2, wherein the drive unit rotates the cab until the center of gravity of the cab is located forward of a tilt center by using the cab tilt cylinder. .