Work vehicles

Abstract

To provide a working vehicle which prevents an operator of a working vehicle from putting a crane apparatus in a dead-end state.SOLUTION: A working vehicle comprises a control device 12 for a crane apparatus 21. The control device 12 has an overload prevention function to regulate operations on the crane apparatus 21 when the condition of the crane apparatus 21 reaches the overload condition. The control device 12 regulates the operation toward the safety side when the loads suspended by the crane apparatus 21 reaches a load dropping prohibited area with the overload condition maintained, after the crane apparatus 21 is operated toward the safety side which is allowed in the overload condition when the overload prevention function is activated. It is possible to prevent the crane apparatus 21 from being in a dead-end state because the regulations etc. of the operation are carried out when it is known in advance that the load enters the load dropping prohibited area with the overload prevention function activated.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a work vehicle, and more particularly to a work vehicle equipped with an overload prevention device. [Background technology]

[0002] A loading truck crane, which is one type of work vehicle, is a vehicle that has a crane device mounted on a truck with a loading platform. The crane device is mounted between the driver's cab and the loading platform. The crane device is operated by drawing power from a driving motor. With a loading truck crane, when performing crane operations, the boom of the crane device rotates around the base of the crane device, and the boom is extended and lowered. These operations are used to lift cargo and transport it.

[0003] Patent Document 1 discloses an overload prevention device for a loaded truck crane. FIG. 8 shows an explanatory diagram of the operation of a conventional loaded truck crane 50. The overload prevention device regulates a predetermined operation of the crane device 61 when the state of the crane device 61 of the loaded truck crane 50 reaches an overload state (for example, a state of a load factor of 110% as shown in FIG. 8(A)). Here, the overload state is a state in which the tipping moment acting on the crane device 61 exceeds the rated moment required for the stability of the crane device 61. The tipping moment changes depending on the rotation, extension, and elevation of the boom constituting the crane device 61. When the boom is extended with a load suspended, the tipping moment increases. Similarly, when the boom is lowered with a load suspended, the tipping moment increases. In addition, when the boom is moved from the side to the front of the loaded truck crane 50 with a load suspended, the rated moment in the front is smaller than the rated moment in the side, so the ratio of the overturning moment to the rated moment becomes larger.

[0004] When this overload prevention device is in operation, movement in the direction that increases the overturning moment is restricted, but movement in the direction that decreases the overturning moment is not restricted or warned in any way, and it is possible to operate the crane so that the load factor reaches 102% as shown in Figure 8(B). In other words, when an overload state is reached, the boom retraction and boom erection are permitted. This is to return the crane apparatus 61 to a normal state that is not overloaded. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-58856 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the loaded truck crane 50, when the boom is retracted or raised from the state shown in Fig. 8(A) to the state shown in Fig. 8(B), the load suspended from the hook at the tip of the boom approaches the base of the boom. Near the base of the boom, there are the driver's cab 62, outriggers 63, and platform fence, and there is an area where the suspended load will interfere when it is lowered, that is, a load drop prohibited area. When the overload prevention device is working, the operation in the direction that increases the tipping moment is restricted, so if the load reaches the load drop prohibited area while in an overloaded state, the load cannot be lowered because the load drop prohibited area is in the direction that decreases the tipping moment, and the direction to leave the load drop prohibited area is the direction that increases the tipping moment, so the crane cannot be operated due to the function of the overload prevention device, resulting in a so-called dead end state.

[0007] SUMMARY OF THE PRESENT INVETION The present invention has been made in consideration of the above circumstances, and has an object to provide a work vehicle, such as a loading truck crane, that prevents an operator of the work vehicle from putting the crane device into a dead end state. [Means for solving the problem]

[0008] The work vehicle of the first invention is equipped with a control device for a crane apparatus, and the control device has an overload prevention function that restricts operation of the crane apparatus when the state of the crane apparatus reaches an overload state, and when the overload prevention function is working, when the crane apparatus is operated to the safe side, which is permitted in the overload state, the load suspended by the crane apparatus is lifted while the overload state is maintained, Predefined by model When the crane reaches a no-loading area, the control device at least restricts operation to the safety side or notifies an operator of the crane equipment that the no-loading area has been reached. The work vehicle of a second invention is the first invention, characterized in that the movement towards the safety side is only either a retracting movement of the crane apparatus or an erecting movement of the crane apparatus. A work vehicle of a third invention is the first or second invention, characterized in that the control device restricts the operation of the crane apparatus to the safety side after notifying an operator of the crane apparatus. Effect of the Invention

[0009] According to the first invention, when the overload prevention function is activated and it is determined in advance that a load will enter a no-load-drop area while the crane equipment is operating to the safe side, the operation is restricted, etc., thereby preventing the crane equipment from reaching a dead end state. According to the second aspect of the present invention, the operation to the safe side is only either the raising operation or the retracting operation of the crane apparatus, so the operation of the crane apparatus is narrowed down to one, making it easier for the worker to check the operation of the crane apparatus. Also, the calculation load of the control device can be reduced because the calculation of whether the load suspended by the crane apparatus will reach the no-loading area is not complicated in advance. According to the third invention, the control device notifies the operator of the crane equipment and then restricts the operation to the safe side, so that the operator of the crane equipment can continue operating to the safe side until the operation to the safe side is restricted, and can continue working until the crane equipment is in a dead end state. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is an operation flow diagram of the work vehicle according to the first embodiment of the present invention. [Diagram 2] 1 is a side view of a work vehicle according to a first embodiment of the present invention. [Diagram 3] FIG. 3 is a hydraulic circuit diagram of the work vehicle of FIG. 2. [Figure 4] 3 is a control circuit diagram of the work vehicle of FIG. 2. [Diagram 5] Fig. 5 is an explanatory diagram of the operation of the work vehicle of Fig. 2. Fig. 5(A) is a diagram showing the state before operation to the safety side, and Fig. 5(B) is a diagram showing the state after operation to the safety side. [Figure 6] FIG. 11 is an operation flow diagram of a work vehicle according to a second embodiment of the present invention. [Figure 7] FIG. 11 is an operation flow diagram of a work vehicle according to a third embodiment of the present invention. [Figure 8] 8A and 8B are explanatory diagrams of the operation of a conventional work vehicle, in which Fig. 8A shows the state before operation to the safety side, and Fig. 8B shows the state after operation to the safety side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Next, an embodiment of the present invention will be described with reference to the drawings. However, the embodiment shown below is an example of a work vehicle for embodying the technical concept of the present invention, and the present invention does not limit the work vehicle to the one described below. For example, a work vehicle equipped with a crane device at the rear of the loading platform is also included. Note that the size or positional relationship of the members shown in each drawing may be exaggerated for clarity of explanation.

[0012] First Embodiment (Loading truck crane 10) Fig. 2 shows a side view of a work vehicle according to a first embodiment of the present invention. The work vehicle in this embodiment is a loaded truck crane 10. As shown in Fig. 2, the loaded truck crane 10 has a crane device 21 mounted on a vehicle frame 29 between a driver's cab 27 and a bed 28 of a general-purpose truck 20. A bed fence 24 is attached to the front end of the bed 28. The general-purpose truck 20 has front wheels 22 symmetrically arranged on the left and right. Furthermore, the general-purpose truck 20 has rear wheels 23 symmetrically arranged on the left and right.

[0013] As shown in Fig. 2, the crane apparatus 21 includes a base 30 fixed on a vehicle frame 29, a post 31 rotatably provided with respect to the base 30, a boom 32 provided on the upper end of the post 31 so as to be able to be raised and lowered, and an outrigger unit 33 provided on the base 30 and extending outward to the left and right from the base 30. That is, the outrigger unit 33 is located between the operator's cab 27 and the loading platform 28 when viewed from the side. Hydraulic jacks 38 (see Fig. 3) are provided on the left and right ends of the outrigger unit 33, respectively. The boom 32 is configured in a nested manner by a base boom, an intermediate boom, a tip boom, etc., and extends and retracts by extending and retracting an internal boom extension actuator 46b (see Fig. 3).

[0014] A winch is built into the post 31. A wire rope is led from this winch to the tip of the boom 32 and passed around a hook 34 via a pulley at the tip of the boom 32, so that the hook 34 is suspended from the tip of the boom 32.

[0015] The crane apparatus 21 is hydraulically driven by a hydraulic circuit 40, which will be described later. A group of levers 35 for operating this hydraulic circuit 40 is provided on both the left and right sides of the base 30. In addition, the base 30 is provided with a control device 12 that electrically controls the hydraulic circuit 40 and controls the work vehicle.

[0016] (Hydraulic circuit 40) Fig. 3 shows a hydraulic circuit diagram of the loading truck crane 10. As shown in Fig. 3, the hydraulic circuit 40 of the crane device 21 mainly includes a hydraulic valve unit 41, a hydraulic pump 43 that supplies hydraulic oil in a tank 42 to the hydraulic valve unit 41, a main oil passage 44 that connects the hydraulic pump 43 and the hydraulic valve unit 41, a return oil passage 45 that connects the hydraulic valve unit 41 and the tank 42, a plurality of crane device actuators 46 for performing the raising and lowering operation of the crane device 21, the extending and retracting operation of the boom 32, the rotating operation of the boom 32, the lifting and lowering operation of the winch, and two jacks 38. The crane device actuators 46 and the jacks 38 are connected to the hydraulic valve unit 41.

[0017] The hydraulic pump 43 is connected to the engine 36 of the utility truck 20 via a PTO (power take-off) device and is driven by the engine 36 .

[0018] The hydraulic valve unit 41 is provided with a boom rotation control valve 47a, a boom extension / retraction control valve 47b, a boom hoist control valve 47c, a winch control valve 47d, a right jack control valve 48a, and a left jack control valve 48b. The boom rotation control valve 47a is connected to the boom rotation actuator 46a, the boom extension / retraction control valve 47b is connected to the boom extension / retraction actuator 46b, the boom hoist control valve 47c is connected to the boom hoist actuator 46c, and the winch control valve 47d is connected to the winch hydraulic motor 46d. The right jack control valve 48a is connected to the jack 38 located on the right side, and the left jack control valve 48b is connected to the jack 38 located on the left side.

[0019] A lever is attached to each of these switching control valves, and by manually operating the lever, it is possible to switch the direction and flow rate of the hydraulic oil supplied from the hydraulic pump 43. The levers attached to the control valves are provided on both the left and right sides of the base 30 as a lever group 35 (see FIG. 2).

[0020] The control device 12 is also connected to an ECU (engine control unit) of the engine 36, and is configured to be able to control at least the rotation speed of the engine 36. The control device 12 can control the rotation speed of the hydraulic pump 43 by controlling the rotation speed of the engine 36, and can adjust the discharge amount of the hydraulic pump 43.

[0021] (Control circuit) 4 shows a control circuit diagram of the loaded truck crane 10. The input side of the control device 12 is electrically connected to the boom length detector 15, the boom rotation angle detector 16, the boom hoist angle detector 17, and the hoisting support force detector 18. The output side of the control device 12 is electrically connected to the alarm 14, the boom rotation control valve 47a, the boom extension and contraction control valve 47b, the boom hoist control valve 47c, the winch control valve 47d, the right jack control valve 48a, and the left jack control valve 48b. Note that the notation of the input side and the output side of the control device 12 is for convenience, and for example, the pressure value of the boom hoist control valve 47c may be input to the control device 12.

[0022] The boom length detector 15 detects the length of the boom 32, and is, for example, a cord payout length detector. The cord payout length detector detects the payout length of the measuring cord by detecting the amount of rotational displacement of the cord winder.

[0023] The boom rotation angle detector 16 detects the rotation angle of the boom 32 and is disposed on the base side of the post 31. For example, the boom rotation angle detector 16 is a potentiometer. A rotary encoder may be used instead of the potentiometer.

[0024] The boom hoist angle detector 17 detects the hoist angle of the boom 32 and is disposed at the base side of the boom 32. For example, the boom hoist angle detector 17 is a potentiometer. A rotary encoder may be used instead of the potentiometer.

[0025] The alarm 14 is for notifying the user of the loading truck crane 10 of a predetermined condition, for example, when the lifting load exceeds the rated load. In this embodiment, the alarm 14 is provided outside the operator's cab 27.

[0026] The hoisting support force detector 18 is provided to detect the load suspended from the hook 34. In this embodiment, the hoisting support force detector 18 is a differential pressure gauge provided on a boom hoisting cylinder. The differential pressure detected by the hoisting support force detector 18 is output to the control device 12. Note that the detection of the load suspended from the hook 34 is not limited to detection by the hoisting support force detector 18. For example, it is also possible to detect the load from the line pull load using a load cell.

[0027] (Overload prevention function and operation flow of this embodiment) The overload prevention function of the control device 12 is a function that restricts the operation of the crane device 21 when the state of the crane device 21 reaches an overload state. In the loaded truck crane 10, the load that can be lifted by the hook 34 for each working radius and hoisting angle, i.e., at that location, is defined as the rated load. This is because the load that can be lifted varies depending on the length of the boom 32 and the hoisting angle of the boom 32. For this reason, the concepts of rated moment and overturning moment are introduced, and when the value of this overturning moment exceeds the value of the rated moment, the control device 12 determines that an overload state has occurred as the overload prevention function, and restricts, for example, the extension operation and the overturning operation of the boom 32. Note that it is also possible to use a load value other than the moment as the reference value for overload determination.

[0028] For example, the rated moment and the overturning moment are calculated from the length of the boom 32, the boom hoisting angle of the boom 32, the swing angle of the boom 32, the pressure of the boom hoist control valve 47c, and the like.

[0029] Fig. 1 shows an operation flow diagram of the loading truck crane 10 in this embodiment, and Fig. 5 shows an operation explanatory diagram thereof. This embodiment relates to the operation after the crane device 21 reaches an overloaded state.

[0030] In step 10 (hereinafter written as S10), the operator of the crane apparatus 21 starts an operation to move the overloaded crane apparatus 21 (for example, the crane apparatus 21 in the state shown in FIG. 5(A)) to the safe side. This operation to move to the safe side corresponds to an operation to retract the boom 32 and an operation to raise the boom 32. It is no problem if each operation is performed independently, or if the two operations are performed simultaneously. When two operations are performed simultaneously, it is preferable that the two operations are programmed to be performed simultaneously with one switch.

[0031] At the same time as the worker starts the operation toward the safety side, the control device 12 calculates whether or not the cargo suspended from the hook 34 of the crane device 21 will reach a cargo no-descent area, for example, as shown in Figure 5 (B), if the operation toward the safety side is continued.

[0032] The no-loading-of-luggage area is an area where the luggage will interfere with the driver's cab 27, the outrigger unit 33, the loading platform fence 24, etc., when it is lowered. The no-loading-of-luggage area is determined in advance depending on the model of the loading truck crane 10, etc. The no-loading-of-luggage area is stored in a memory unit in the control device 12, for example.

[0033] In S20, when the luggage moves into the luggage drop prohibited area, the control device 12 judges whether the calculated load calculated from the load actually suspended at that location exceeds the rated load, i.e., whether the overload state continues (synonymous with whether the tipping moment exceeds the rated moment). If the control device 12 judges that the calculated load is within the rated load, i.e., the overload state has been eliminated by an operation to the safe side, the control device 12 judges that the luggage is not in an overloaded state but in a normal state, and controls the luggage to continue to operate in accordance with the operation of the operator.

[0034] In S20, if the control device 12 determines that the calculated load is greater than the rated load, i.e., that the overload state continues, in S30, the control device 12 restricts at least one of the permitted safe movements, i.e., the raising movement and the retracting movement, or notifies the operator of the crane device 21 that the load has reached the load drop prohibited area. Both the movement restriction and the notification to the operator can be performed, or only one of them can be performed. The notification to the operator can be performed, for example, by using an alarm 14 connected to the control device 12, or can be displayed on the screen of an operation terminal held by the operator.

[0035] When the overload prevention function is activated and it is determined in advance that the operation of the crane device 21 toward the safety side will cause the cargo to enter an area where cargo descent is prohibited, the operation is restricted, thereby preventing the crane device 21 from reaching a dead end state.

[0036] <Second embodiment> Fig. 6 shows an operation flow diagram of a work vehicle according to a second embodiment of the present invention. In this embodiment, the work vehicle is also a loaded truck crane 10. The configuration of the loaded truck crane 10 is the same as that of the first embodiment. This embodiment differs from the first embodiment in the portion S10 of the operation flow diagram in Fig. 1.

[0037] As shown in FIG. 6, in the second embodiment, when the crane apparatus 21 is in an overload state, in S11, the control device 12 prohibits the two operations, the raising operation and the retracting operation, which are operations toward the safety side, from being performed simultaneously.

[0038] In S12, the operator of the crane apparatus 21 performs either the raising operation or the retracting operation, and the control device 12 selects either the raising operation or the retracting operation.

[0039] In S13, the control device 12 calculates the calculated load for the standing up operation if the operator of the crane device 21 selects the standing up operation, or calculates the calculated load for the contracting operation if the operator of the crane device 21 selects the contracting operation.

[0040] In S20, the control device 12 judges whether the calculated load calculated from the actual suspended load exceeds the rated load, i.e., whether the overload state continues, if the luggage moves into the luggage drop prohibited area. If the control device 12 judges that the calculated load is within the rated load, i.e., the overload state has been eliminated by an operation to the safe side, the control device 12 judges that the luggage is not in an overload state but in a normal state, and controls the luggage to continue to operate in accordance with the operation of the operator, as in the first embodiment.

[0041] In S20, if the controller 12 determines that the calculated load is greater than the rated load, that is, that the overload state continues, in S30, as in the first embodiment, the controller 12 restricts even permitted safe operations, or notifies the operator of the crane apparatus 21 that the load has reached a load drop prohibited area, as shown in Fig. 1. Both the operation restriction and the notification to the operator may be performed, or only one of them may be performed. The notification to the operator may be performed, for example, using an alarm 14 connected to the controller 12.

[0042] Since the operation to the safety side is only either the contraction operation of crane apparatus 21 or the raising operation of crane apparatus 21, the operation of crane apparatus 21 is narrowed down to one, making it easier for the worker to check the operation of crane apparatus 21. Also, the calculation load of control device 12 can be reduced because the advance calculation of whether the load suspended by crane apparatus 21 will reach the no-loading area is not complicated.

[0043] <Third embodiment> Fig. 7 shows an operation flow diagram of a work vehicle according to a third embodiment of the present invention. In this embodiment, the work vehicle is also a loaded truck crane 10. The configuration of the loaded truck crane 10 is the same as that of the first embodiment. This embodiment differs from the first embodiment in the portion S30 of the operation flow diagram in Fig. 1.

[0044] 7, when the control device 12 determines in S20 that the calculated load is greater than the rated load, that is, that the overloaded state continues, the control device 12 notifies the operator of the crane device 21 in S31 that the cargo will reach a cargo no-drop area while the overloaded state continues. This notification can be made, for example, by an alarm 14 connected to the control device 12, or can be displayed on the screen of an operation terminal held by the operator.

[0045] In S32, if the control device 12 determines that the cargo has not reached the boundary of the no-load area, the control device 12 allows operation toward the safe side permitted in an overload state, and the operator of the crane device 21 continues the operation.

[0046] In S32, when the control device 12 determines that the cargo has reached the boundary of the cargo drop prohibited area, the control device 12 restricts the operation toward the safety side, that is, both the raising operation and the retracting operation of the crane apparatus 21. In addition, it is also possible to emit a sound from the alarm 14 that is different from the alert given in S31. Note that even in this case, the configuration may be such that the operator of the crane apparatus 21 can operate the crane apparatus 21 toward the safety side again by returning the operation switch on the operation terminal or the like to the neutral position.

[0047] The control device 12 notifies the operator of the crane apparatus 21 and then restricts the operation to the safe side, so that the operator of the crane apparatus 21 can continue operating to the safe side until the operation to the safe side is restricted, and can continue working until the crane apparatus 21 is in a dead end state.

[0048] In the third embodiment, the only difference from the first embodiment is step S30, but in other embodiments, S10 can be that of the second embodiment and S30 can be that of the third embodiment.

[0049] In addition, the work vehicles in the first to third embodiments have been described by taking the loading truck crane 10 as an example of a work vehicle, but the work vehicle is not limited to this. For example, the work vehicle may generally include a wide range of work vehicles having a crane device 21, such as a normal truck crane or an all-terrain crane. [Explanation of symbols]

[0050] 10 Loading truck crane 12 Control device 21 Crane equipment

Claims

1. A control device for a crane device is provided, The control device has an overload prevention function that restricts operation of the crane device when the state of the crane device reaches an overload state, When the overload prevention function is activated, a safe operation of the crane apparatus that is permitted in the overload state is performed, When the load suspended by the crane apparatus reaches a load drop prohibition area that is predetermined by the type while the overload state is maintained, The control device at least one of restricting the operation to the safety side or notifying an operator of the crane device that the crane device has reached the no-load-drop area. A work vehicle characterized by:

2. The movement to the safety side is Only one of the contraction operation of the crane apparatus or the erection operation of the crane apparatus, 2. The work vehicle according to claim 1.

3. The control device notifies the operator of the crane device, Restricting the operation to the safe side; 3. A work vehicle according to claim 1 or 2.

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