JPH0122789Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a driver's cab lifting device for a cab-over type automobile or the like.

[Prior Art] Conventionally, in cab-over type automobiles, etc., in which the engine is installed below the driver's cab, a device for lifting the driver's cab has been installed in order to inspect or repair the engine. In some cases, especially those whose cabs are heavy and have low rigidity, cab lifting devices are provided on both sides of the cab.

Conventional configurations in which cab lifting devices are provided on both sides of such a cab are as shown in FIGS. 1, 2, and 3.

FIG. 1 shows a sectional view in which one actuator device 10 of a conventional cab lifting device is interposed between a cab 5 and a chassis 6, and the cab 5 is connected to the chassis 6 in front of it. 5a indicates a perpendicular line drawn above the pivot point, and the degree in which the actuator device 10 lifts the driver's cab 5 in FIG. Fig. 2 shows a state in which the center of gravity of the driver's cab is behind the perpendicular line 5a, that is, a state in which the weight of the driver's cab 5 is applying a compressive force to the piston 1b. This shows a state in which the center of gravity of the driver's cab 5 is in front of the perpendicular line 5a, that is, a state in which the weight of the driver's cab 5 is applying a pulling force to the piston 1b.

FIG. 3 shows a system diagram of the driver's cab lifting device in FIG. 1 or 2. FIG.

In FIG. 1 or 2, the actuator device 10 is provided on both the left and right sides of the driver's cab 5 in the direction of movement, but in FIG. 1 or 2, the actuator device 10 is only on the left side.
The actuator device 10 on the right side corresponds to the actuator device 10 shown on the right side in FIG.
0 corresponds to the actuator device 10 shown on the left side of FIG. 3, and these left and right actuator devices 10 have exactly the same configuration as shown in FIG. 3.

Therefore, in the following description, in principle, the left actuator device 10 will be described as a representative.

The actuator device 10 includes an actuator 1
A piston 1b is fitted into the cylinder 1a bored in the cylinder 1a so as to be able to slide in the axial direction, and the pipe line 4 is connected to the throttle channel 4a.
and the displacement chamber 1c via the pilot check valve 4b, and the pipe line 3 is connected to the displacement chamber 1c via the throttle channel 3a and the pilot check valve 3b.
d, the pilot line 4c in the pilot check valve 3b communicates with the line 4, the pilot line 3c in the pilot check valve 4b communicates with the line 3, the piston 1b is connected to the cab 5, The cylinder 1a is connected to the chassis 6.

In the conventional configuration described above, the operation is as follows.

When pressure oil is fed into the pipe line 3 and the pipe line 4 is opened to a reservoir (not shown), in the left and right actuator devices 10, 10, the pressure oil in the pipe line 3 passes through the pilot pipe line 3c to the pilot check valve 4b. The valve opens, and at the same time, the pressure oil in the pipe line 3 flows through the throttle flow path 3a and the pilot check valve 3b.
through the piston 1 to the displacement chamber 1d.
b is pushed upward, and the displacement chamber 1c is pushed away by the piston 1b due to the pushing up.
The hydraulic oil is pilot check valve 4b, respectively.
The piston 1b, which is discharged into the reservoir through the throttle channel 4a and the pipe line 4 and is raised by this action, pushes up the driver's cab 5 as shown in FIG. 1 or 2.

In this case, since the driver's cab 5 is pivotally connected to a part of the chassis 6 in front of it as described above, as the respective pistons 1b and 1b push up the driver's cab 5, the result will be as shown in FIG. 1 or 2. As shown in the figure, the driver's cab 5 is tilted forward and lifted.

When the cab 5 is lifted, the pipe 3 is opened to the reservoir and pressure oil is pumped into the pipe 4. In the left and right actuator devices 10, 10, the pressure oil in the pipe 4 is transferred via the pilot pipe 4c. The pilot check valve 3b is opened, and at the same time, the pressure oil in the pipe line 4 is sent under pressure to the displacement chamber 1c via the throttle channel 4a and the pilot check valve 4b, and the pressure oil in the displacement chamber 1c pushes down the piston 1b. .

Due to this pushing down, the hydraulic oil displaced from the displacement chamber 1d is transferred to the pilot check valve 3b.
and the pistons 1 of the left and right actuator devices 10, 10 are discharged from the conduit 3 to the reservoirs via the throttle channels 3a, respectively.
b respectively descend, and those pistons 1b
As for the descent, cab 5 is lowered.

When the conduits 3 and 4 are simultaneously opened to the reservoir during lifting or lowering of the cab 5 as described above, the pilot conduits 3c and 4c are also brought to atmospheric pressure due to the opening, and the pilot check valve is closed. 3b and 4b are both in the same state as a normal check valve, but in this case, the operating state of the cab lifting device is as shown in Figure 1 and as shown in Figure 2. The effect is as follows.

As mentioned above, when the driver's cab 5 is lifted or lowered to the extent shown in FIG. Acting on piston 1b
As a result, the hydraulic fluid in the displacement chamber 1d is in a pressurized state when the driver's cab 5 is lifted or lowered.

Therefore, in this case, since the pipe line 3 is open to the reservoir, the hydraulic fluid in the pressurized displacement chamber 1d flows into the pilot check valve 3.
However, the pilot check valve 3b automatically closes due to the flow attempting to flow out, and as a result, the piston 1b is fluidly restrained, and the piston 1b is connected to the cab. 5
is designed to be able to hold it in that position.

Furthermore, when the degree of lifting or lowering of the cab 5 is as shown in FIG. A tensile force is applied to the piston 1b, and as a result, the hydraulic oil in the displacement chamber 1c is in a pressurized state when the driver's cab 5 is lifted or lowered.

Therefore, in this case, since the pipe line 4 is open to the reservoir, the hydraulic fluid in the pressurized displacement chamber 1c flows through the pilot check valve 4.
However, the pilot check valve 4b automatically closes due to the flow attempting to flow out, and as a result, the piston 1b is fluidly restrained, and the piston 1b is connected to the cab. 5
is designed to be able to hold it in that position.

Furthermore, the above-mentioned fluid restraint of the piston 1b is
As mentioned above, when the conduits 3 and 4 are opened to the reservoir, they respond very sensitively. This is because if the response is slow, the cab 5 will continue to descend within a certain range even after it has stopped, which is dangerous.

Also, this good response means that each of the pilot check valves 3b or 4b is designed to operate with very high sensitivity, which means that the pilot check valves 3b or 4b are connected to Or, when hydraulic oil flows out to pilot check valve 3,
This is because the structure is such that b or 4b flows out in a slightly open state.

[Problems to be solved by the invention] However, as mentioned above, the pilot check valve 3
b and 4b operate very sensitively, the following problems occur when the cab 5 is lowered in the state shown in Figure 1 and when the cab 5 is lifted in the direction of arrow b in Figure 2. A point exists.

That is, to explain this using an example in which pipes 3 and 4 are simultaneously opened to the reservoir as the cab 5 descends in the state shown in FIG. When descending, hydraulic oil flows out from the left and right displacement chambers 1d, 1d into the pipe line 3 via the pilot check valves 3b, 3b, respectively. Since the hydraulic oil flows out in a slightly open state, the amount of hydraulic oil flowing out from the left and right pilot check valves 3b, 3b per unit time does not match. As a result, the left and right pistons 1b descend at different speeds, and the different speeds cause the driver's cab 5 to descend while tilting laterally.

This also applies when the driver's cab 5 is tilted in the direction of arrow b in the state shown in FIG.

This causes the driver's cab 5 to be twisted, and this phenomenon must be improved.

An object of the present invention is to provide a driver's cab lifting device that improves the above-mentioned problems.

[Means for solving problems] The present invention consists of the following structure.

Each of the first check valve device and the second check valve device includes: a: a first check valve and a second check valve connected in series between the first pipe line and the second pipe line; A second check valve and a pilot check valve are interposed in parallel, and b: A third pipe line is communicated between the first check valve and the second check valve. Each of the first actuator and the second actuator device is configured such that: a: a piston is fitted into the cylinder so as to be able to slide in the axial direction; b: one of the axial pistons in the cylinder; a first displacement chamber is formed on the side thereof, and a second displacement chamber is formed on the other side; c: either one of the piston or the cylinder is connected to the driver's cab; The other end of the check valve device has the above-mentioned configuration, and the driver's cab is pivotally connected to a part of the chassis other than the part to which the piston or the cylinder is connected, and the first check valve device In the second pipe line, the second displacement chamber in either the first actuator or the second actuator communicates with the second pipe line, and the third pipe line communicates with the second displacement chamber in either the first actuator or the second actuator. In the second check valve device configured as described above, wherein the second displacement chamber in either the other of the actuator or the first actuator communicates with each other, the second conduit includes: The first displacement chamber in either the first actuator or the second actuator communicates with the third conduit, and the third conduit is connected to either the second actuator or the first actuator. The first displacement chamber in the first check valve device is in communication with the first displacement chamber, and the first pilot pipe line of the pilot check valve in the first check valve device is in communication with the first displacement chamber in the second
A second pilot line of the pilot check valve in the second check valve apparatus communicates with a first line in the check valve apparatus, and a second pilot line of the pilot check valve in the second check valve apparatus communicates with the first line of the pilot check valve in the second check valve apparatus.
The check valve device is connected to the first pipe line in the check valve device, and has the above configuration.

[Function] The function of the configuration of the present invention described above is as follows.

In the following explanation, for convenience of explanation, a: the second displacement chamber communicating with the second pipe line of the first check valve device is named "one second displacement chamber", and b: The second displacement chamber communicating with the third pipe line of the first check valve device is named "another second displacement chamber," and c: the second pipe of the second check valve device. d: The first displacement chamber communicating with the third conduit of the second check valve device is named "another first displacement chamber." We will name it "No. 1 Pushing Room."

When pressurized fluid is pumped into the first conduit in the first check valve device and the first conduit in the second check valve device is opened to the reservoir, the pressure fluid is transferred to the second conduit.
The pilot check valve in the second check valve device is opened via the pilot line, and in the first check valve device, the pressure fluid in the first line is opened via the pilot check valve. The working fluid in the first conduit is forced to push up the piston in the actuator, and at the same time, the working fluid in the first conduit is forced into the second check valve and the third conduit. The actuating fluid is pumped through the channel into another second displacement chamber, and the pumped working fluid pushes up the piston in the pumped actuator.

As mentioned above, the working fluid displaced by their respective pistons drains into the reservoir via the second check valve arrangement as described below.

On the side of the second check valve device, the working fluid displaced from the other first displacement chamber is discharged into the reservoir via the pilot check valve and the first conduit, and at the same time The working fluid displaced in the displacement chamber is discharged into the reservoir via the third line, the first check valve, the pilot check valve and the first line.

In this case, in the second check valve device, the second check valve is closed by the flow of the working fluid discharged from the first displacement chamber, and the second check valve is closed by the flow of the working fluid discharged from the first displacement chamber. The working fluid is not discharged directly into the pipe line 1.

In this way, the first actuator and the second
In the actuator shown in FIG. It is lifted up to the state shown in Figure 2.

Contrary to the above operation, when pressure fluid is force-fed to the first conduit in the second check valve device and the first conduit in the first check valve device is opened to the reservoir, the pressure fluid is transferred to the first conduit in the first check valve device. The pilot check valve in the first check valve device is opened via the first pilot pipe, and on the side of the second check valve device, the pressure fluid in the first pipe opens the pilot check valve in the first check valve device. and a second conduit to the other first displacement chamber, the pumped working fluid depresses the piston in the pumped actuator, and at the same time, the working fluid in the first pipe is pumped into the second displacement chamber. The hydraulic fluid is pumped into the first displacement chamber through the check valve and the third conduit, and the pumped working fluid depresses the piston in the actuator.

As mentioned above, the working fluid in the respective second displacement chambers displaced by their respective pistons drains into the reservoir via the first check valve arrangement as described below.

On the side of the first check valve device, the working fluid displaced from the second displacement chamber is discharged into the reservoir via the second line, the pilot check valve and the first line, and at the same time , the working fluid displaced in the other second displacement chamber is discharged into the reservoir via the third line, the first check valve, the pilot check valve and the first line.

In this case, in the first check valve device, the second check valve is closed by the flow of the working fluid discharged from the other displacement chamber, and the second check valve is closed by the flow of the working fluid discharged from the other second displacement chamber. There is no direct discharge of working fluid to.

In this way, the first actuator and the second
In the actuator shown in FIG. The state shown in Figure 2 is returned to the normal position set on the chassis.

In this case, since the driver's cab is pivoted at a part of the chassis other than the part to which the piston or cylinder is connected, the state in which the driver's cab is lifted by the first actuator and the second actuator is The following two states exist.

Draw a perpendicular line above the pivot point where the driver's cab is pivoted to the chassis, and when lifting the driver's cab, 1. The center of gravity of the driver's cab will be at the first and second points from the perpendicular line.
actuator, the weight of the cab exerts a compressive force on the first and second actuators, thereby causing the working fluid in one second displacement chamber and the other second displacement chamber to is in a pressurized state, and the center of gravity of the cab is at the first and second points from the perpendicular line.
actuator, the weight of the cab exerts a pulling force on the first and second actuators, causing actuation in one first displacement chamber and the other first displacement chamber. The fluid is pressurized.

For this reason, when lifting or lowering the driver's cab as described above, the first pipe line in the first check valve device and the first pipe line in the second check valve device If the reservoir is opened at the same time, the opening also opens the second pilot line and the first pilot line to the reservoir, and both pilot check valves in the first and second check valve devices normally operate. As a result, the operation is similar to that of the check valve in the above case, and as a result, the operation can hold the cab in that position, but the operation in this case is both the case 1) and the case 2) above, as described below. It will be divided into cases.

That is, in case 1) above, since the working fluid in one second displacement chamber and the other second displacement chamber are in a pressurized state, on the side of the first check valve device, The working fluid pressurized in the second displacement chamber attempts to discharge into the reservoir via the second line, the pilot check valve and the first line, and is pressurized in the other second displacement chamber. The working fluid attempts to discharge into the reservoir through the third pipe line, the first check valve, the pilot check valve, and the first pipe line, and the flow of the working fluid to be discharged causes the pilot check to be discharged. The valve automatically closes and prevents the flow of the working fluid, so that the cab is fluidly held in that position.

In this case, the second check valve automatically closes the flow that is trying to be discharged directly from the third pipe line to the first pipe line, and prevents the flow from flowing out. There is.

In contrast to the above situation, in the case of 2) above,
Since the working fluid in one first displacement chamber and the other first displacement chamber is in a pressurized state, the other first displacement chamber is pressurized on the second check valve device side. The working fluid attempts to discharge into the reservoir via the second line, the pilot check valve and the first line, and the working fluid pressurized in the first displacement chamber passes through the third line, the first line. The flow of working fluid to be discharged automatically closes the pilot check valve and prevents its operation. Fluid escape is prevented, so that the cab is fluidly held in its position.

In this case as well, the second check valve automatically closes the flow that is attempting to be discharged directly from the third pipe line to the first pipe line, and also prevents the flow from flowing out. ing.

As mentioned above, in the case of 1) or 2), the driver's cab is The action of holding it in place is such that it is held securely at the same time as the first conduit is opened to the reservoir.

That is, when the working fluid is being discharged to the first line in the first or second check valve device, the pilot check valves discharge pressure into the first or second pilot line. When the fluid pressure signal to the pilot pipe disappears because the valve is being discharged in a slightly open state, the valve is opened by the fluid pressure signal being sent to the pilot pipe. This is because the pilot check valves will immediately close off the flow of the working fluid that they are discharging.

Furthermore, when the working fluid is being discharged to the first pipe line in the first or second check valve device by lifting or lowering the driver's cab, the first check valve is not activated. The flow resistance as the fluid flows out is negligibly small compared to the flow resistance of the pilot check valve when the fluid flows out.

This is because the first check valves are ordinary check valves, and these ordinary check valves are designed to have very low flow resistance when operated in the direction of passing the working fluid.

From the above, in the case of 1) above, the first
When the working fluid is discharged from the check valve device to the first pipe line, the working fluid is discharged from the second displacement chamber to the first pipe line via the second pipe line and the pilot check valve. When the working fluid is discharged, and when the working fluid is discharged from another second displacement chamber to the first conduit through the third conduit, the first check valve and the pilot check valve, the flow resistance is: It is essentially equal to the flow resistance through the pilot check valve only.

As a result, the flow rate of the working fluid per unit time discharged from one second displacement chamber and the flow rate of the working fluid per unit time discharged from the other second displacement chamber become equal, and the flow rate of the working fluid per unit time discharged from the second displacement chamber becomes equal. The speed at which the driver's cab is lifted by the second actuator and the second actuator is the same speed.

Similarly, in the case of 2) above, when the working fluid is discharged from the second check valve device to its first pipe line, the working fluid is discharged from the other first displacement chamber to the second pipe line and the pilot check valve. When the working fluid is discharged from the first displacement chamber to the first pipe line through the third pipe line, the first check valve, and the pilot check valve, Even when fluid is discharged, its flow resistance is
It is essentially equal to the flow resistance through the pilot check valve only.

As a result, the flow rate of the working fluid per unit time discharged from the other first displacement chambers and the flow rate of the working fluid per unit time discharged from one first displacement chamber become equal, and the flow rates of the working fluid discharged from the other first displacement chambers per unit time are equal to each other. Beyond the position, the first actuator and the second actuator further lift and tilt the cab at the same speed.

In addition, when the above-mentioned cab is lifted or lowered and the position of the cab is maintained in the state of 1) above, and the engine is inspected or repaired under the cab in that state, the first When the third pipe line in the check valve device is damaged, the working fluid in the other second displacement chamber flows out from the damaged part, and the actuator constituting the other second displacement chamber is becomes unable to hold the driver's seat.

However, in this case, although the working fluid tries to flow out from the damaged part from the second displacement chamber, the first check valve is interposed between the second displacement chamber and the damaged part. Since the flow that is about to flow out closes the first check valve, the flow of the working fluid from the second displacement chamber to the damaged part is prevented, and the second displacement chamber of the one The actuator constituting the chamber holds the driver's cab in that position. In such a case, in particular: a. By configuring the first check valve device integrally with the first actuator, , the configuration is such that one actuator device is mounted on one side of the cab, and the second check valve device is integrally configured with the second actuator, so that the configuration is changed to the other side of the cab. the other actuator device to be attached to the side; b: and the second displacement chamber of the first actuator is the second displacement chamber of the first actuator;
When the other second displacement chamber is configured as the second displacement chamber in the second actuator, the following effects occur.

The first check valve device and the first actuator are configured as an integrated actuator device, and the second conduit in the first check valve device communicates with the second displacement chamber in the first actuator. Therefore, the second conduit is enclosed within one of the actuator devices, and it is highly unlikely that the second conduit will be damaged.

On the other hand, the third pipe line in the first check valve device is routed between one actuator device and the other actuator device while being exposed to the outside. Therefore, the third conduit is in a state where it is easily damaged in case of any emergency.

However, even if the third conduit were to be damaged as described above, one actuator device would hold the driver's cab due to the presence of the first check valve as described above, and in such a case, Prevents the driver's cab from falling.

In addition, when the above-mentioned cab is lifted or lowered and the position of the cab is maintained in the state of 2) above, and the engine is inspected or repaired under the cab in that state,
When the third pipe line in the second check valve device is damaged, the working fluid in the first displacement chamber flows out from the damaged part, forming the first displacement chamber. The actuator that is in the position will no longer be able to hold the driver's cab.

However, in this case, the working fluid tries to flow out from the damaged part from the other first displacement chamber, but the first check valve is interposed between the other first displacement chamber and the damaged part. Since the flow that is about to flow out closes the first check valve, the flow of the working fluid from the other first displacement chamber to the damaged part is prevented, and the other first displacement chamber closes the first check valve. The actuator forming the chamber holds the cab in position.

In such a case, in particular, a: By configuring the second check valve device integrally with the second actuator, the configuration can be used as the other actuator device mounted on the other side of the driver's cab. , by configuring the first check valve device integrally with the first actuator, the configuration becomes one actuator device that is mounted on one side of the driver's cab; Let the displacement chamber be the first displacement chamber in the first actuator,
In the case where the above-mentioned other first displacement chamber is used as the first displacement chamber in the second actuator, the above configuration is as follows.

The second check valve device and the second actuator are configured as an integrated actuator device, and the second conduit in the second check valve device communicates with the first displacement chamber in the second actuator. Therefore, the second conduit is enclosed within the other actuator device, and it is highly unlikely that the second conduit will be damaged.

On the other hand, the third pipe line in the second check valve device is routed between the other actuator device and one actuator device while remaining exposed to the outside. Therefore, the third conduit is in a state where it is easily damaged in case of any emergency.

However, even if the third conduit is damaged as described above, the presence of the first check valve in the second check valve device allows the other actuator device to close the cab. This prevents the driver's cab from falling in such cases.

In particular, a: the first check valve device is configured integrally with the first actuator, so that the configuration is one actuator device mounted on one side of the cab, and the second check valve device is configured as one actuator device mounted on one side of the cab; By configuring the check valve device integrally with the second actuator, the configuration becomes the other actuator device mounted on the other side of the driver's cab; The second pipe is
communicating with the second displacement chamber in the first actuator, a third conduit in the first check valve device communicating with the second displacement chamber in the second actuator, c: second check valve; A second conduit in the device is communicated with a first displacement chamber in the second actuator, and a third conduit in the second check valve device is communicated with the first displacement chamber in the first actuator 1. When this is done, the following effects occur.

That is, in this case, the pipes communicating between one actuator device and the other actuator device are the third pipe line in the first check valve device and the third pipe line in the second check valve device. becomes.

Therefore, when lifting the driver's cab, any pipe or both pipes communicating between one actuator device and the other actuator device (the third pipe in the first check valve device and Even if the third conduit in the second check valve device is damaged, as can be understood from the above explanation of the operation, the driver's cab will always be operated by either the first actuator or the second actuator. will be retained.

As mentioned above, when the cab is in the state shown in FIG. 1, the first actuator holds the cab in that position, and the lifted state of the cab is in the state shown in FIG. This is because at some times the second actuator holds the cab in that position.

[Example] The present invention will be described below based on examples.

FIG. 4 shows a system diagram of a cab lifting device as an embodiment of the present invention, and is an improved version of the conventional cab lifting device shown in FIG. 1 or 2. The actuator device 10A corresponds to the actuator device 10 provided on the left side in the direction of movement of the cab 5 in FIG. 1 or 2, and the actuator device 10A provided on the right side of the cab 5 is the fourth actuator device This corresponds to the actuator device 10B in the figure.

The actuator device 10A has a piston 1b fitted into the cylinder 1a of the actuator 1 so as to be able to slide in the axial direction, and the displacement chamber 1c is connected to the actuator device 10B via a third conduit 1h.
The first pipe line 3 is connected to the throttle passage 3a, the pilot check valve 3b and the second pipe line 7g.
The pilot check valve 3b is connected to the displacement chamber 1d via a pipe 1i, and the pilot pipe 3c of the pilot check valve 3b communicates with the pipe 4. The first check valve 1e and the second check valve 1f connected in series are Road 1i
and a pilot check valve 3b,
Check valves 1e and 1f, first pipe line 3, second
The pipe line 1i and the third pipe line 2 constitute a first check valve device on the side of the actuator device 10A, the piston 1b is connected to the driver's cab 5, and the cylinder 1a is connected to the chassis 6. .

In the actuator device 10B, a piston 7b is fitted into a cylinder 7a of the actuator 7 so as to be able to slide in the axial direction, and the first pipe line 4 is connected to a throttle passage 4a, a pilot check valve 4b and a second pipe line 7i. The displacement chamber 7d communicates with the conduit 1g via the third conduit 2, and the pilot conduit 4c in the pilot check valve 4b communicates with the conduit 3 and is connected in series. The first check valve 7e and the second check valve 7f are connected between the first pipe line 4 and the second pipe line 7i, and the pilot check valve 4b and the first check valve 7
e, second check valve 7f, first pipe line 4, second
The pipe line 7i and the third pipe line 1h constitute a second check valve device in the actuator device 10B, the piston 7b is connected to the driver's cab 5, and the cylinder 7a is connected to the chassis 6.

The operation of the embodiments of the present invention described above will be explained below.

When pressure fluid is fed to the pipe line 3 and the pipe line 4 is opened to a reservoir (not shown), the pressure fluid in the pipe line 3 passes through the pilot pipe line 4c, opens the pilot check valve 4b, and The pressure fluid in the piston 1 is fed under pressure to the displacement chamber 1d via the throttle channel 3a, the pilot check valve 3b and the pipe 1i.
At the same time, the working fluid in the pipe 3 is forced into the displacement chamber 7d via the check valve 1f and the pipe 2, and the pumped working fluid pushes up the piston 7b.

As mentioned above, the working fluid in the displacement chamber 1c displaced by the piston 1b is discharged to the reservoir via the pipes 1h and 7g, the check valve 7e, the pilot check valve 4b, the throttle channel 4a and the pipe 4. At the same time, the working fluid in the displacement chamber 7c displaced by the piston 7b is discharged to the reservoir via the pipe 7i, the pilot check valve 4b, the throttle passage 4a and the pipe 4.

In this case, the check valve 7f is connected to the displacement chamber 1.
It is closed by the flow of the working fluid discharged from the displacement chamber 1c, and there is no possibility that the working fluid is directly discharged from the displacement chamber 1c to the pipe line 4.

In this way, in the actuator devices 10A and 10B, the pistons 1b and 7b are pushed up, thereby causing the pistons and cylinders to extend relative to each other, and as a result, the cab 5
is lifted relative to the chassis 6 to the state shown in FIG. 1 or 2.

Contrary to the above operation, when pressure fluid is force-fed to the pipe line 4 and the pipe line 3 is opened to the reservoir, the pressure fluid in the pipe line 4 opens the pilot check valve 3b via the pilot pipe line 3c, and The pressure fluid No. 4 is sent under pressure to the displacement chamber 1c via the check valve 7f and the pipe line 1h to push up the piston 1b,
At the same time, the pressure fluid in the conduit 4 is restricted to the constricted flow path 4a,
It is fed under pressure to the displacement chamber 7c via the pilot check valve 4b and the conduit 7i, and pushes down the piston 7b.

As mentioned above, the working fluid in the displacement chamber 1d displaced by the piston 1b is
i. The working fluid in the displacement chamber 7d, which is discharged into the reservoir via the pilot check valve 3b, the throttle passage 3a and the line 3, and at the same time is displaced by the piston 7b, is discharged into the reservoir via the pilot check valve 3b, the throttle passage 3a and the line 3. It is discharged into the reservoir via valve 1e, pilot check valve 3b, throttle channel 3a and pipe 3.

In this case, the check valve 1f is the displacement chamber 7.
It is closed by the flow of the working fluid discharged from the displacement chamber 7d, and there is no possibility that the working fluid is directly discharged from the displacement chamber 7d to the conduit 3.

As the pressure fluid is fed to the displacement chambers 1c and 7c in this manner, the pistons and cylinders in the actuators 1 and 7 are relatively contracted, thereby causing the driver's cab 5 to move relative to the chassis 6. Then, the state shown in FIG. 1 or 2 is returned to the normal position set on the chassis.

In this case, the cab 5 has the piston 1b
and 7b are pivotally connected in a part of the chassis 6 other than where they are connected, the state in which the driver's cab 5 is lifted by the actuator devices 10A and 10B is different from that shown in FIGS. 1 and 2 described above. As explained, the following two states exist.

Draw a perpendicular line 5a onto the pivot point where the driver's cab 5 is pivoted to the chassis 6. 1. If the center of gravity of the driver's cab 5 is on the right side of the perpendicular line 5a as shown in FIG. The weight of the platform 5 acts as shown by the arrow a, and the weight applies compressive force to the pistons 1b and 7b, pressurizing the working fluid in the displacement chambers 1d and 7d, so that the center of gravity of the cab 5 is In the state shown in FIG. 2, which is to the left of the perpendicular line 5a, the weight of the cab 5 acts as shown by arrow b, and the weight applies a pulling force to the pistons 1b and 7b, displacing them. The working fluid in chambers 1c and 7c is pressurized.

Due to this, the driver's cab 5
If lines 3 and 4 are simultaneously opened to the reservoir while lifting or lowering the
Due to the opening, the pilot line 4c is opened to the reservoir via the line 3, and the pilot line 4c is opened to the reservoir via the line 3.
c is also open to the reservoir via line 4, and each of the two pilot check valves 4b and 3b becomes like a normal check valve, so that by its action it is possible to hold the cab 5 in its position. However, the effect in this case can be divided into the cases 1) and 2) above, as described below.

That is, in case 1) above, since the working fluid in the displacement chambers 1d and 7d is in a pressurized state, the working fluid pressurized in the displacement chamber 1d flows through the pipe 1i, the pilot check valve 3b, and the throttle flow. The working fluid which is being pressurized in the displacement chamber 7d and is about to be discharged into the reservoir via the line 3a and the line 3 is discharged through the line 2, the check valve 1e, the pilot check valve 3b, the throttle passage 3a and the line 3. However, the flow of the working fluid to be discharged automatically closes the pilot check valve 3b, preventing the working fluid from flowing out, and as a result, the operator's cab 5 It will be fluidly held in position.

In this case, the check valve 1f automatically closes the flow that is to be directly discharged from the pipes 2 and 1g to the pipe 3 by the action of the flow, thereby preventing the flow from flowing out.

In contrast to the above situation, in the case of 2) above,
Since the working fluid in the displacement chambers 1c and 7c is in a pressurized state, the working fluid pressurized in the displacement chamber 7c is transferred to the reservoir via the pipe 7i, the pilot check valve 4b, the throttle passage 4a and the pipe 4. The working fluid that is being pressurized in the displacement chamber 1c is being discharged to the pipes 1h and 7g, and the check valve 7.
e. The pilot check valve 4b is automatically closed by the flow of the working fluid to be discharged into the reservoir via the pilot check valve 4b, throttle channel 4a and pipe 4; The outflow of the working fluid is prevented, so that the cab 5 is fluidly held in its position.

In this case as well, the check valve 7f automatically closes the flow that is to be directly discharged from the pipes 1h and 7g to the pipe 4 by the action of the flow, thereby preventing the flow from flowing out.

As mentioned above, in the case of 1) or 2) above
In this case, the effect of holding the cab 5 in that position by simultaneously opening conduits 3 and 4 to the reservoir is to ensure that the cab 5 is held at the same time as conduits 3 and 4 are opened to the reservoir. This is due to the following reasons.

When the working fluid is being discharged to the pipe 3 or 4, the pilot check valve 3b or 4
The valve b is designed to be discharged in a slightly open state depending on a fluid pressure signal sent to the pilot pipe 3c or 4c.

Therefore, when the fluid pressure signal to the pilot line 3c or 4c disappears, the pilot check valve 3b or 4b can immediately close the flow of the working fluid being discharged.

Furthermore, when the working fluid is discharged into the pipe 3 or 4 by lifting or lowering the driver's cab 5, the flow resistance of the working fluid flowing out through the check valves 1e or 7e is as follows.
Compared to the flow resistance of the pilot check valve 3b or 4b at the time of outflow, this value is negligibly small.

This is because the check valves 1e and 7e are ordinary check valves, and these ordinary check valves are designed to have very small flow resistance when operated in a direction to allow working fluid to pass through.

For this reason, in case 1) above (in the state shown in Figure 1), when the working fluid is discharged to the first pipe line 3 via the first check valve device, it is necessary to discharge the working fluid from the displacement chamber 1d. Even when the working fluid is discharged to the first pipe line 3 via the second pipe line 1i, the pilot check valve 3b and the throttle passage 3a, the working fluid is discharged from the displacement chamber 7d to the third pipe line 2 and the first check valve. 1e,
Even when the working fluid is discharged into the first line 3 via the pilot check valve 3b and the throttle channel 3a, the flow resistance is substantially equal to the flow resistance flowing only through the pilot check valve 3b.

As a result, the flow rate of the working fluid per unit time discharged from the displacement chamber 1d becomes equal to the flow rate of the working fluid per unit time discharged from the displacement chamber 7d, so that the actuator 1 and the actuator 7 each have the driver's cab 5. The lowering speed remains the same.

Similarly, when the working fluid is discharged from the displacement chamber 7c to the first conduit 4 via the second check valve device in case 2) (the state shown in FIG. 2), the second When the working fluid is discharged to the first pipe line 4 through the pipe line 7i, the pilot check valve 4b and the throttle passage 4a, and when the working fluid is discharged from the displacement chamber 1c to the third pipe line 1h, the first check valve 7e, Even when the working fluid is discharged into the first conduit 4 via the pilot check valve 4b and the throttle channel 4a, the flow resistance is substantially equal to the flow resistance flowing only through the pilot check valve 4b. .

As a result, the flow rate of the working fluid discharged from the displacement chamber 7c per unit time and the flow rate of the working fluid discharged from the displacement chamber 1c per unit time become equal, and the flow rate of the working fluid per unit time discharged from the displacement chamber 1c becomes equal, and the piston 1b and the piston 1b exceed the position of the perpendicular line 5a. 7b lifts and tilts the driver's cab 5 to the state shown in FIG. 2 at the same speed.

Furthermore, when the position where the cab 5 is lifted or lowered is maintained in the state shown in FIG. 1, and the engine is inspected or repaired under the cab 5 in that state, , when the pipe line 2 communicating between the actuator device 10A and the actuator device 10B is damaged, the working fluid in the displacement chamber 7d flows out from the damaged part, and the piston 7
b becomes unable to hold the driver's cab 5.

However, in this case, the working fluid also tries to flow out from the displacement chamber 1d to the damaged part, but since the first check valve 1e is interposed between the displacement chamber 1d and the damaged part, The flow which is about to flow out closes the first check valve 1e, preventing the flow of working fluid from the displacement chamber 1d to the damaged part, and the piston 1b holds the cab 5 in that position.

Note that if the side of the pipe line 1h that communicates the actuator device 10A and the actuator device 10B is damaged in the state shown in FIG. 1, this state is a state in which the working fluid in the displacement chambers 1c and 7c is expanded. That is, since the working fluid in the displacement chambers 1c and 7c is not in a state to support the pistons 1b and 7b, it is impossible for the driver's cab 5 to fall due to damage to the pipe line 1h.

Furthermore, when the cab 5 is lifted or lowered in the position shown in FIG. 2, the engine may be inspected or repaired under the cab 5 in that condition. If the pipe line 1h that communicates the actuator device 10A and the actuator device 10B is damaged, the working fluid in the displacement chamber 1c will flow out from the damaged part, and the piston 1b will displace the driver's cab 5. It becomes impossible to hold it.

However, in this case, the working fluid also tries to flow out from the displacement chamber 7c to the damaged part, but since the first check valve 7e is interposed between the displacement chamber 7c and the damaged part, The flow which is about to flow out causes the first check valve 7e to close, preventing the flow of working fluid from the displacement chamber 7c to the damaged part, and the piston 7b holding the cab 5 in that position.

Note that if the side of the pipe line 2 that communicates the actuator device 10A and the actuator device 10B is damaged in the state shown in FIG. 2, this state is a state in which the working fluid in the displacement chambers 1d and 7d is expanded. , that is, the displacement chamber 1
The working fluids d and 7d are connected to the pistons 1b and 7
Since it is not in a state to support b, the pipe 2
It is impossible for the driver's cab 5 to fall due to damage.

In addition, in the explanation of the operation shown in FIG. 4 above, the role of the throttle channel 3a or 4a is that the check valve function of the pilot check valve 3b or 4b is suppressed when a foreign object is caught in the seat of the pilot check valve 3b or 4b. When this becomes incomplete, the speed at which the working fluid is discharged into the pipe 3 or 4 is throttled to prevent the operator's cab 5 from falling rapidly.

Furthermore, in the above description of FIG. 4, even if the first actuator 1 and the first check valve device are not necessarily configured integrally, the essence of the present invention does not change; It will be easily understood that the essence of the present invention does not change even if the second check valve device is not integrated.

In addition, in the above description of FIG. 4, instead of communicating the pipe line 2 with the displacement chamber 7d, the pipe line 2 is made to communicate with the displacement chamber 1d, and the pipe line 1i
Instead of communicating with the displacement chamber 1d,
Even if the pipe line 1i is configured to communicate with the displacement chamber 7d, the essence of the present invention remains the same.

However, in such a configuration, the actuator device 10A and the actuator device 10B
In this case, as described above, if the communicating pipe 1i is damaged, the working fluid in the displacement chamber 7d will flow out from the damaged part, and Push-off room 1
The working fluid in d is also connected to the pipe line 2, the check valve 1e,
It will flow out from the damaged part via the pipe line 1i.

On the other hand, in the piping configuration of FIG. 4, since the pipe line 1i can be enclosed inside the integral structure of the actuator device 10A, first, the pipe line 1i
If the pipe 2 exposed to the outside for piping between the actuator device 10A and the actuator device 10B is damaged,
As explained above, the presence of the first check valve 1e allows the actuator device 10A to hold the driver's cab 5.
It can be said that the configuration shown in FIG. 4 is superior.

Similarly, in the above description of FIG.
h to the displacement chamber 1c, the conduit 1h is communicated to the displacement chamber 7c, and instead of communicating the conduit 7i to the displacement chamber 7c, the conduit 7i is connected to the displacement chamber 1c. The essence of the present invention is the same even if the configuration is made to communicate with 1c.

However, in such a configuration, the actuator device 10A and the actuator device 10B
In this case, as mentioned above, if the communicating pipe 7i is damaged, the working fluid in the displacement chamber 1c will flow out from the damaged part, and Pushing room 7
The working fluid in c is also connected to pipe 1h and check valve 7.
e, it will flow out from the damaged part via the pipe 7i.

On the other hand, in the piping configuration shown in FIG. 4, the piping 7i can be enclosed inside the integral structure of the actuator device 10B.
There is no possibility of damage to the pipe line 1h, which is exposed to the outside for piping between the actuator device 10A and the actuator device 10B, and if the pipe line 1h exposed to the outside is damaged, the first
Because the presence of the check valve 7e allows the actuator device 10B to hold the driver's cab 5, it can be said that the configuration shown in FIG. 4 is superior.

In addition, in the above description of the present invention, the piston 1
b and piston 7b are connected to the driver's cab 5, and the cylinder 1a and cylinder 7a side are connected to the chassis 6, but in the present invention, on the contrary, the piston 1b and the piston 7b are connected to the chassis 6. ,
It will be easily understood that even if the cylinder 1a and the cylinder 7a are configured to be connected to the driver's cab 5, the essence remains the same.

[Effects of the invention] As is clear from the above explanation, the effects of the invention are as follows.

1 As described above, the second displacement chamber 7d in the second actuator 7 and the second displacement chamber 1d in the first actuator 1 are both connected to each other via the pilot check valve 3b in the first check valve device. By discharging the working fluid into the first conduit 3, the outflow resistance of the working fluid when the working fluid is discharged from the displacement chamber 1d and the displacement chamber 7d to the conduit 3 becomes equal, so that When descending, the driver's cab 5 descends while maintaining its horizontal position.

In addition, the first actuator 1
The displacement chamber 1c of the second actuator 7 and the first displacement chamber 7c of the second actuator 7 are configured to discharge the working fluid to the first pipe line 4 through the pilot check valve 4b of the second check valve device. Therefore, by lifting the driver's cab 5 in the direction of arrow b in the state shown in FIG. The outflow resistance at the time of outflow is equal to the outflow resistance outflowing from the displacement chamber 1c to the pipe line 4 and the outflow resistance outflowing from the displacement chamber 7c, and when the cab 5 is further lifted in the state shown in FIG. The driver's cab 5 is lifted while maintaining its horizontal position.

As a result, the pilot check valve 3b or 4b is designed to discharge the working fluid when the valve is slightly opened, but the operation of the driver's cab 5 at the time of discharge causes twisting of the driver's cab 5. The driver's cab 5 can be operated without having to do so.

This contributes to preventing twisting of the driver's cab 5, compared to the conventional operation of the driver's cab 5 in which the driver's cab 5 could not be maintained horizontally.

2 In addition, the driver's cab lifting device according to the present invention has a first check valve 1e in the first check valve device.
and a second check valve 2e are provided, and a third pipe line 2 connecting between the first check valve 1e and the second check valve 1f is connected to the second Since the structure is configured such that it communicates with the displacement chamber 1d or 7d, even if the third pipe line 2 in the first check valve device is damaged when the cab 5 is lifted up in the state shown in FIG. , the driver's cab 5 will not fall.

Further, the second check valve device is provided with a first check valve 7e and a second check valve 7f, and a third check valve communicating between the first check valve 7e and the second check valve 7f is provided. Since the conduit 1h is configured to communicate with one of the displacement chambers of the first actuator 1 or the second actuator 7, when the driver's cab 5 is lifted up as shown in FIG. Even if the third pipe line 1h in the valve device is damaged, the driver's cab 5 will not fall.

This contributes to ensuring safety when lifting the driver's cab 5.

3 In the above case, in particular, a: By configuring the first check valve device integrally with the first actuator 1, the configuration can be changed to the one installed on one side of the driver's cab 5. By configuring the actuator device 10A and the second check valve device integrally with the second actuator 7, the configuration is changed to the other actuator device 10B mounted on the other side of the driver's cab 5, b: Second pipe line 1 in the first check valve device
i is the second actuator in the first actuator 1
The third pipe line 2 of the first check valve device communicates with the second displacement chamber 7d of the second actuator 7. When configured as above, the following effects can be obtained. get.

In the first check valve device, the second conduit 1i is enclosed within one actuator device 10A, so the second conduit 1i will not be damaged by external force.

On the other hand, the third pipe line 2 in the first check valve device is exposed to the outside and communicates between the actuator device 10A on one side and the actuator device 10B on the other side. Even if the third pipe line 2 is damaged and the lifted state is as shown in Fig. 1, the presence of the first check valve 1e in the first check valve device by the first actuator 1
The driver's cab 5 is held in that position, and its safety is improved.

4 Furthermore, a: The first check valve device is configured integrally with the first actuator 1, and the configuration is such that one actuator device 10A is installed on one side of the driver's cab 5, and the second check valve device is configured integrally with the first actuator 1. The check valve device is integrally configured with the second actuator 7,
Its configuration is the other actuator device 10B installed on the other side of the driver's cab 5, and b: the second pipe line 7 in the second check valve device.
i is communicated with one displacement chamber 7c in the second actuator 7, and the third pipe line 1h in the second check valve device is communicated with one displacement chamber 1c in the first actuator 1. obtains the following effect.

In the second check valve device, the second conduit 7i is enclosed within the other actuator device 10B, so the second conduit 7i will not be damaged by external force.

On the other hand, the third pipe line 1h in the second check valve device is exposed to the outside and communicates between one actuator device 10A and the other actuator device 10B. When being lifted, if the third pipe 1
h is damaged and its lifting is in the state shown in FIG. 2, the presence of the first check valve 7e in the second check valve device prevents the second actuator 7
This will hold the driver's cab 5 in that position, further improving its safety.

5 In particular, a: By configuring the first check valve device integrally with the first actuator 1, the configuration can be changed to one actuator device 10A mounted on one side of the driver's cab 5. , by configuring the second check valve device integrally with the second actuator 7, its configuration becomes the other actuator device 10B mounted on the other side of the driver's cab 5, b: the first The second pipe line 1 in the check valve device of
i is the second actuator in the first actuator 1
c: the third pipe line 2 in the first check valve device communicates with the second displacement chamber 1d in the second actuator 7; 2 conduit 7
i is communicated with one displacement chamber 7c in the second actuator 7, and the third pipe line 1h in the second check valve device is communicated with one displacement chamber 1c in the first actuator 1. obtains the following effect.

As can be understood from the effects of 3) and 4) above, when lifting the driver's cab 5, which pipe (first or second) communicating between one actuator device 10A and the other actuator device 10B Even if the third conduit 2 or 1h) or both of the third conduit 2 or 1h in the check valve device is damaged, if the cab 5 is lifted up as shown in FIG. When the driver's cab 5 is held in that position and the driver's cab 5 is lifted up as shown in FIG. 5 from falling.

[Brief explanation of the drawing]

1 and 2 are side views of a conventional cab lifting device installed in a car, and in FIG. 1 or 2, the actuator device 10 is replaced with the actuator device of the present invention. , Fig. 1 or 2 is an embodiment of the present invention as it is, Fig. 3 is a system diagram showing a conventional cab lifting device, and Fig. 4 is a system diagram of the conventional cab lifting device. An embodiment of the platform lifting device is shown in a system diagram. The symbols used in the examples are as follows.
1 and 7: Actuator, 1a and 7a:
Cylinders, 1b and 7b: Pistons, 1c, 1
d, 7c and 7d: displacement chamber, 1e, 1f,
7e and 7f: check valve, 1g, 1h, 1
i, 7g and 7i: pipe line, 2: pipe line, 3 and 4: pipe line, 3a and 4a: throttle channel, 3b and 4b: pilot check valve, 3c and 4
c: Pilot conduit, 5: Cab, 6: Chassis.

Claims (1)

[Claims for Utility Model Registration] 1. Each of the first check valve device and the second check valve device is: a: connected in series between the first pipe line and the second pipe line; the first check valve and the second
A check valve and a pilot check valve are interposed in parallel, b. A third pipe line is communicated between the first check valve and the second check valve. None, each of the first actuator and the second actuator: a: A piston is fitted into the cylinder so as to be able to slide in the axial direction; b: In the cylinder, one side of the piston in the axial direction forms a first displacement chamber, and the other side forms a second displacement chamber, c: either the piston or the cylinder is connected to the driver's cab, and the other of the piston or the cylinder is connected to the driver's cab; The first check valve device has the above-mentioned configuration and is connected to a chassis, and the driver's cab is pivotally attached to a part of the chassis other than the part to which the piston or the cylinder is connected, and the first check valve device has the above-mentioned configuration. The second displacement chamber in either the first actuator or the second actuator communicates with the second conduit, and the third conduit communicates with the second displacement chamber in either the first actuator or the second actuator. In the second check valve device configured as described above, wherein the second displacement chamber in one of the first actuators is in communication with the second displacement chamber, the second The first displacement chamber in either one of the actuator or the second actuator communicates with the third conduit, and the first displacement chamber in the other of the second actuator or the first actuator communicates The first displacement chamber communicates with the pilot check valve in the first check valve device, and the first pilot pipe line of the pilot check valve in the first check valve device communicates with the second displacement chamber.
A second pilot line of the pilot check valve in the second check valve apparatus communicates with a first line in the check valve apparatus, and a second pilot line of the pilot check valve in the second check valve apparatus communicates with the first line of the pilot check valve in the second check valve apparatus.
A driver's cab lifting device having the above configuration and communicating with the first pipe line in the check valve device. 2 a: By configuring the first check valve device integrally with the first actuator, the configuration becomes one actuator device mounted on one side of the driver's cab, and the second check valve device is integrated with the first actuator. By configuring the valve device integrally with the second actuator, the configuration thereof becomes the other actuator device mounted on the other side of the driver's cab, and b: the second check valve device in the first check valve device. A utility model wherein the conduit communicates with a second displacement chamber in the first actuator, and the third conduit in the first check valve device communicates with a second displacement chamber in the second actuator. A driver's cab lifting device according to claim 1. 3 a: By configuring the first check valve device integrally with the first actuator, the configuration becomes one actuator device mounted on one side of the driver's cab, and the second check valve device is integrated with the first actuator. By configuring the valve device integrally with the second actuator, the configuration thereof becomes the other actuator device mounted on the other side of the driver's cab, and b: the second actuator device in the second check valve device. A utility model wherein the conduit communicates with the first displacement chamber in the second actuator, and the third conduit in the second check valve device communicates with the first displacement chamber in the first actuator. A driver's cab lifting device according to claim 1. 4 a: By configuring the first check valve device integrally with the first actuator, the configuration becomes one actuator device mounted on one side of the driver's cab, and the second check valve device is integrated with the first actuator. By configuring the valve device integrally with the second actuator, the configuration thereof becomes the other actuator device mounted on the other side of the driver's cab, and b: the second check valve device in the first check valve device. a conduit communicates with a second displacement chamber in the first actuator, a third conduit in the first check valve device communicates with a second displacement chamber in the second actuator, c: The second conduit in the second check valve device communicates with the first displacement chamber in the second actuator, and the third conduit in the second check valve device communicates with the first displacement chamber in the first actuator. The driver's cab lifting device according to claim 1, which communicates with the displacement chamber.