JPS6235652Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a drive device for a cab tail mechanism, and is capable of guaranteeing safety when driving the cab tail mechanism.

A cab tilt mechanism is a mechanism for tilting the cab of a cab-over type automobile to expose the engine part. Generally, this cab tail mechanism has a power cylinder, and the power cylinder is driven by hydraulic pressure to perform a predetermined operation. However, the cab tail mechanism according to the prior art does not have a means to notify that it is being driven, and therefore there is a problem with safety during the drive.

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, an object of the present invention is to provide a drive device for a cab tail mechanism that can guarantee safety when driving the cab tail mechanism. The technical concept of the present invention, which achieves this object, is based on the fact that a warning means such as a buzzer is driven by switching a switching valve that changes the elevation of the cab tail mechanism.

Embodiments of the present invention will be described in detail below with reference to the drawings. As shown in FIGS. 1 and 2, the hydraulic circuit includes a hydraulic pump 2 driven by a motor 1, and a manual hydraulic pump 3 connected in parallel to the hydraulic pump 2 for use in the event of a failure of the motor 1. , a manual switching valve 4 for switching the cab tail mechanism up and down, and a power cylinder 5 for lifting and lowering a driver's cab (not shown). When starting the cab tail as shown in FIG.
position) to supply pressure oil to the power cylinder 5. At this time, the piston 5 of the power cylinder 5
Pressure oil acts on piston 5a from above and below, but the force acting on the upper surface of piston 5a is smaller by the cross-sectional area of piston rod 5b, so the differential pressure causes piston 5a to rise and start a tilting motion. Further, the control valve 6 is a valve equipped with a pilot and operates when pressure oil is present at point A, and communicates in both directions. On the other hand, when the cab starts lowering as shown in FIG. 2, the manual switching valve 4 is operated to the right in the figure (down position) to supply pressure oil to the power cylinder 5. At this time, pressure oil acts on the upper surface of the piston 5a of the power cylinder 5, while the lower surface of the piston rod 5a is opened to the oil tank 7, so the piston 5a descends and starts the cab lowering operation. In addition, 8, 8a, 8b, 8 in the figure
C is a filter, 9, 9a, 9b, 9c, and 9d are check valves, and 10 is a relief valve that operates when the pressure at point B becomes abnormally high and releases this pressure to the oil tank 7 side. .

The motor 1 of this hydraulic circuit is driven by being supplied with current from a battery 12 by the operation of a relay 11. At this time, the conditions for operating the relay 11 are as follows.

(i) When manual switching valve 4 is in the up position (during cab tail operation).

In this case, the manual changeover valve switch 4a is the first
Since the position shown in the figure, that is, the tail-up side contact 4b is selected, the switches 13, 14, and 15 of the tail-up detection circuit consisting of the carburetor switch 13, power cylinder switch 14, and tail switch 15 are turned on.

(ii) When manual switching valve 4 is in the down position (during cab lowering operation).

In this case, the manual changeover valve switch 4a is
Since the position shown in the figure, that is, the tilt-down side contact 4c is selected, each switch 15, 1 of the tilt-down detection circuit consisting of the cab drive detection switch 16 and the tilt switch 15 is selected.
6 is ON.

At this time, the cab lock switch 13 is in the OFF state (normally) in which the cab is locked to prevent it from tilting by a cab lock lever (not shown), which is a cab lock device, and is locked by operating the cab lock lever. When you release
Turns on. Therefore, for example, the limit switch a that operates when the cab lock lever is released.
Formed using contacts. The power cylinder switch 14 is normally ON, and is turned OFF when the cab reaches a predetermined highest position due to cab tilt operation. Therefore, for example, it is formed using the b contact of a limit switch that operates when the driver's cab reaches its highest position. The tail switch 15 is a switch that can be turned ON and OFF by manual operation, and is turned OFF during normal operation and turned ON when the cab is tilted or lowered. The cab drive detection switch 16 is turned OFF when the driver's cab is in the lowest position, that is, the normal position, and turned ON when the cab is tilted or lowered.
It is a switch that is named. Therefore, for example, it is formed using the b contact of a limit switch that operates when the driver's cab is in the lowest position (normal position).

A buzzer 17, which is the alarm means of this embodiment, is connected to ground at a position between the power cylinder switch 14, the cab drive detection switch 16, and the tail switch 15 via diodes 18 and 18a. As a result, the battery 12, manual changeover valve switch 4a, cab lock switch 13,
Power cylinder switch 14 and diode 18
The circuit leading to the buzzer 17 via the battery 1
2. A circuit is formed which leads to the buzzer 17 via the manual changeover valve switch 4a, the cab drive detection switch 16, and the diode 18a.

Next, the operation of this embodiment will be explained together with the tilt operation procedure. First, remove the cab lock lever. This turns the cab lock switch 13 ON. Subsequently, the manual switching valve 4 is operated to the up side to turn on the tail switch 15. As a result, the coil 11a of the relay 11 is energized and the relay 11 is operated, so that the motor 1 is driven and the power cylinder 5 starts the cab tilt operation. This is the state shown in FIG.
At this time, current is also supplied to the buzzer 17, so that it sounds during its operation. When the operator's cab reaches the predetermined highest position as a result of this operation, the power cylinder switch 14 is turned OFF, so the relay 11 is deenergized, the operation of the motor 1 is stopped, and the sound of the buzzer 17 is also stopped. . In this state, turn off tail switch 15.

On the other hand, if the cab is to be lowered from this state, the manual changeover valve switch 4 is operated to the down side and the tail switch 15 is turned on. At this time, since the cab drive detection switch 16 is ON, the relay 11 is operated and the motor 1 is driven, so that the cab lowering operation is started by the power cylinder 5. This is the state shown in FIG. At this time, current is also supplied to the buzzer 17, so that it sounds during its operation. When the cab reaches the lowest position due to this operation, the cab drive detection switch 16 is activated.
Since the relay 11 is turned OFF, the operation of the motor 1 is stopped by deenergizing the relay 11, and the sounding of the buzzer 17 is also stopped.

As specifically explained above with the examples,
According to the present invention, when the cab tilts or lowers the cab, it can be known through the operation of a warning means such as a buzzer that the cab is being tilted or lowered, thereby improving safety.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams showing an embodiment of the present invention. In the drawing, 1 is a motor, 2 is a hydraulic pump, 4 is a manual switching valve, 4a is a manual switching valve switch, 5 is a power cylinder, 11 is a relay, 11a is a coil, 1
2 is a battery, and 17 is a buzzer.

Claims (1)

[Scope of Claim for Utility Model Registration] In a cab tilt mechanism that tilts a driver's cab by switching the hydraulic circuit of pressure oil discharged from a hydraulic pump and expanding and contracting a power cylinder, a relay that supplies current to a motor that drives the hydraulic pump. , a tail switch that opens and closes a circuit that supplies current to the excitation coil of the relay, and a switching valve that selectively switches the power supply current between the tail-up side contact and the tail-down side contact in conjunction with the switching valve that switches the hydraulic circuit. A cab lock switch that closes when the cab lock device that holds the tail-up side contact and the driver's cab from tilting is released, and a power that opens when the power cylinder reaches a predetermined extended position. A tail-up detection circuit in which a cylinder switch and the above-mentioned tail switch are sequentially connected in series, the above-mentioned tail-down side contact, a cab drive detection switch that is opened when the above-mentioned power cylinder reaches a predetermined contracted position, and the above-mentioned tail switch. A driving device for a cab tail mechanism, comprising: a tail down detection circuit connected in series; and an alarm means connected to the tail switch side of the power cylinder switch and the cab drive detection switch.