JPS6326978Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a device for preventing the platform of a dump truck from descending.

Conventional Technology In general, dump trucks are equipped with a safety lock device that is linked to the dump control operating device in the driver's seat. Preventing descent. For example, a non-return fitting is provided on the side of the hydraulic cylinder, one end of a wire is connected to the non-return fitting, and the other end of the wire is connected to an operating device for a dump control in the driver's seat for activation. However, there was a fear that such a device would be damaged due to unexpected large external force.

For this reason, in the hydraulic circuit for operating cargo boxes, etc., the pipe is always maintained in a communicating state in the middle of the communication pipe that communicates the hydraulic cylinder and the control switching valve, and only when necessary, the pipe can be opened by any operation. A safety device for dump trucks, etc. that closes the
In addition, a cargo box is mounted on the vehicle body so that it can be lifted by a hydraulic cylinder for lifting the cargo box, and a mechanical system in a normally open state is inserted in the hydraulic circuit for operating the hydraulic cylinder for lifting the cargo box. an operating type check valve; and an operating device linked to the mechanically operated check valve and configured to extend and hold the box lifting hydraulic cylinder by appropriately operating the mechanically operating type check valve to a closed state; proposed a device for preventing the fall of cargo boxes for dump trucks, etc., which consists of a rotatable operating lever, a transmission cam that converts the rotating motion of the operating lever into reciprocating motion, and an actuating piece as Japanese Patent Publication No. 54-43766. has been done.

However, these devices cannot be used because the switch that operates the control switching valve or the operation lever that operates the mechanically operated check valve is located far away from the operation member for dump control. It was a hassle.

Problems to be Solved by the Invention The purpose of the invention is to address the above-mentioned problems and to enable the lever provided on the operating member for dump control to be engaged by pressing the push button with the hand holding the handle of the operating member for dump control. When the mating member disengages from the stepped part of the fixed member, the switch is opened by the lever to enable the loading platform to tilt, and in that state, the operating member is moved up and down to raise and lower the loading platform, and the push button is pressed. Simply release the lever and engage the engaging member of the lever with the stepped part of the fixed member, and the lever closes the switch to stop the tilting of the loading platform. To provide a device for preventing the lowering of a loading platform of a dump truck, which can be easily operated with one hand while grasping the handle of an operating member for raising and lowering a box.

Means for Solving the Problems In the dump truck platform lowering prevention device of the present invention, an operating member is rotatably provided on a fixed member by a rotating shaft, and the operating member has a pusher protruding from the tip of a handle. A pressing rod having a button is provided so as to be movable in the axial direction of the operating member, the pressing rod is attached to a lever pivotally connected to the operating member, and an engaging member is provided on the lever, and the rotating member is formed on the fixed member. The engaging member is detachably engaged with a plurality of stepped portions sandwiching arcuate peaks centered on the shaft, and a switch is provided on the operating member so that the operating piece of the engaging member is connected to the stepped portion. The switch is provided opposite to the lever so that the switch is released from the lever when the engagement member engages with the stepped part, and comes into contact with the lever to operate the switch when the engagement member does not engage with the step part, and is used to raise the loading platform of a dump truck. A remote operating valve is provided in the oil pipe leading into the hydraulic cylinder, and the switch is connected to the remote operating valve so that the remote operating valve is opened and closed by operating the switch.

Operation By pressing the push button with the hand holding the handle of the operating member, the lever rotates via the push rod, the engagement member of the lever is released from engagement with the plurality of steps, and the operation is completed. The member is rotatable with respect to the fixed member, so that the cargo box can be tilted, and the cargo platform is raised and lowered by raising and lowering the operating member.

When the operating member is in the raised and lowered positions, the pushbutton is pressed to cause the lever to open the switch, the remote-operated valve is deactivated, the oil in the oil pipe is allowed to flow, and the cargo platform can be tilted.

When the push button is released and the engagement member of the lever engages with the stepped portion of the fixed member, the lever leaves the switch and closes the switch, the remote operated valve is operated and the oil in the oil pipe is stopped, The tilting of the loading platform is stopped.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is an overall view of a dump truck equipped with the device of the present invention, in which a dump control operating device 1 is provided in the driver's seat.
is connected to one end of a cable 2 that transmits the operation. The other end of the cable 2 is connected to one end of a link bar 3, and the other end of the link bar 3 is connected to an oil pump 4. The oil pump 4 is connected to an output shaft 6 for engine work via a drive shaft 5, and also to a hydraulic cylinder 8 for lifting the cargo platform 7. In addition, 9 is an arm, 10 is a rotating shaft of the loading platform 7, and 11 is a vehicle body frame.

Figure 2 is a side sectional view of the main parts of the device of the present invention;
The figure is a partially cutaway plan view. Reference numeral 12 denotes a fixed member, which pivotally supports the operating member 13 on a rotating shaft 14. A lever 15 is pivotally attached to the operating member 13 by a lever rotation shaft 16, and a lock pin 22 is provided at one end of the lever 15 on the fixed member 12, sandwiching a mountain portion having an arcuate surface centered on the rotation shaft 14. Engagement step portions 17A and 17B that engage with an engagement member consisting of
will be established. One end of a pressing rod 18 is pivotally attached to the other part of the lever 15 so as to be movable in the axial direction of the operating member 13.
The other end of the pressing rod 18 is fixed to a push button 19 protruding from the tip of a handle portion 23 provided at the end of the operating member 13, and functions together with the push button 19 as a release device. Note that the pressing rod 18 is housed within the operating member 13, a pressing spring receiver 21 is provided in a part of the operating member 13, and a pressing spring 20 is provided between the push button 19 and the pressing spring receiver 21. The other end 15A of the lever 15
extends outside the operating member 13, and a pressing piece 27 of the switch 26 is provided on the operating member 13 opposite to this extension. When the push button 19 is pressed, the switch 26 is opened, and when the push button 19 is released, the switch 26 is opened. so that it is closed. In addition, 24 is the lock pin 22
This is a long groove for guiding.

FIG. 4 is a diagram showing the hydraulic circuit of the hydraulic cylinder 8.
9 are each provided with a solenoid valve 30 which is a remotely operated valve, and connected to the switch 26.

First, in order to raise the loading platform 7, press the push button 19.
While pressing , insert the lock pin 22 into the engaging stepped portion 17B.
When the handle part 23 is lifted upward and the lock pin 22 is brought to the position of the engagement step part 17A, the movement of the operating member 13 is linked to the position shown in FIG.
As shown in FIG. 2, the spool valve 31 is fully pushed in, and the A, B, and C lines of the oil pump 4 are closed. Then, the hydraulic pressure sent from the gear pump 32 enters the chamber 8A of the hydraulic cylinder 8 through the check valve 33 and the pipe 28, pushes up the piston 34 and the piston rod 35, and raises the loading platform 7. At this time, the other end 15A of the lever 15
is in contact with the actuating piece 27 of the switch 26, and the solenoid valve 30
is not activated, and pipes 28 and 29 are filled with oil. In this case, when the push button 19 is released, the switch 26 is closed and the solenoid valve 30 is activated, the flow of oil in the pipes 28 and 29 is stopped, the movement of the piston 34 is stopped, and the loading platform 7 is stopped. The rise stops.

When it is desired to stop the loading platform 7 at a neutral position, the lock pin 22 is positioned between the engagement steps 17A and 17B. Then, as shown in FIG. 4, the spool valve 31 is pulled out one stage, the A line and the B line in the oil pump 4 are connected, and the oil pumped from the gear pump 32 circulates in the oil pump 4 and reaches the piston 34. does not move, and the loading platform 7 remains stationary.

When lowering the loading platform 7 by its own weight, hold down the push button 19 and move the lock pin 22 to the engagement step 17.
A, lower the handle part 23, and remove the lock pin 22.
to the position of the engagement stepped portion 17B. Then,
As shown in FIG. 4, the spool valve 31 has two
The stage is pulled out, the A line and C line in the oil pump 4 are connected, and the oil flows without the aid of the oil pressure of the gear pump 32 due to the weight of the loading platform 7. At this time,
Since the other end 15A of the lever 15 remains in contact with the operating piece 27 of the switch 26, the solenoid valves 30 provided in the pipes 28 and 29 do not operate, and the oil flows in the opposite direction to when the loading platform 7 is raised. . In this case as well, when the push button 19 is released, the other end 15 of the lever 15 is released.
A is separated from the actuating piece 27 of the switch 26, the switch 26 is closed, and the solenoid valve 30 is actuated to open the pipe 2.
8 and 29 is stopped, and the piston 3
4 stops moving, and the lowering of the loading platform 7 is stopped.

Figure 5 is a hydraulic circuit diagram when lowering the loading platform 7 using its own weight and hydraulic pressure.
A″ line and C line are connected and gear pump 32
The hydraulic pressure passes through the B line and the A' line, enters the other chamber 8B of the hydraulic cylinder 8, and lowers the piston 34. At the same time, the loading platform 7 is lowered by its own weight, and the oil in the chamber 8A of the hydraulic cylinder 8 returns to the gear pump 32 from the C line to the A'' line.At this time, the position of the lever 15 is the same as when it is lowered only by its own weight. position, the solenoid valve 30 does not operate and the pipe 2
Oils 8 and 29 also flow in the same direction.

Note that a remote operated valve of another mechanism may be used as the solenoid valve, and the valve may be provided in either or both of the two pipes that send oil to the hydraulic cylinder.

Effects of the invention According to the invention, by pressing the push button with the hand holding the handle of the operating member for dump control, the engaging member of the lever provided on the operating member engages with the stepped portion of the fixed member. When the switch is released, the lever opens the switch to allow the loading platform to tilt, and in that state, the operating member can be moved up and down to move the loading platform up and down, and when the push button is released, the engagement member of the lever is released. By simply engaging the stepped portion of the fixing member, the lever can be used to close the switch and stop the tilting of the loading platform. It can be easily operated with one hand while grasping the handle of the operating member.

[Brief explanation of the drawing]

Fig. 1 is an overall view of a dump truck equipped with the device of the present invention, Fig. 2 is a sectional side view of the main part of the device of the present invention, and Fig. 3 is a partially cutaway plan view of Fig. 2. 4. FIGS. 1, 2, and 3 are hydraulic circuit diagrams of the device of the present invention, and FIG. 5 is a circuit diagram of another embodiment of the hydraulic circuit. 1... Dump control operating device, 4... Oil pump, 7... Loading platform, 8... Hydraulic cylinder,
12... Fixed member, 13... Operation member, 14...
Rotating shaft, 15... Lever, 16... Lever rotating shaft, 17A, 17B... Engaging step portion, 18... Pressing rod, 19... Push button, 20... Pressing spring, 21
... Spring receiver, 22 ... Lock pin, 23 ... Handle section, 26 ... Switch, 27 ... Actuation piece, 2
8, 29... Oil pipe, 30... Solenoid valve, 31...
Spool valve, 32... Gear pump, 33...
Check valve, 34...piston, 35...piston rod.

Claims (1)

[Scope of utility model registration request] An operating member is provided on the fixed member so as to be freely rotatable around a rotating shaft, and the operating member is provided with a press rod having a push button protruding from the tip of the handle portion so as to be movable in the axial direction of the operating member, and the press A rod is attached to a lever pivotally connected to the operating member, and an engaging member is provided on the lever, and a plurality of stepped portions are provided sandwiching a mountain portion having an arcuate surface centered on the rotation axis formed on the fixed member. The engaging member is detachably engaged, and the operating member is provided with a switch that releases the operating piece from the lever when the engaging member engages with the stepped portion, and when the engaging member engages with the stepped portion, the operating piece is released from the lever. A remote operated valve is provided opposite to the lever so that the switch is actuated by contacting the lever when not engaged, and a remote operated valve is provided in an oil feed pipe leading to a hydraulic cylinder for raising the platform of the dump truck, and the remote operated valve is connected to the remote operated valve. A loading platform lowering prevention device for a dump truck, characterized in that the switch is connected to open and close the remotely operated valve by operating the switch.