JP4122903B2 - crane - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a crane provided with a multistage telescopic boom.
[0002]
[Prior art]
A multi-stage telescopic boom of a crane is configured by fitting a box-shaped multi-stage boom body in a telescope shape, and is telescopically driven by a telescopic drive means that combines a hydraulic cylinder or a hydraulic cylinder and a rope mechanism.
[0003]
For example, a conventional technique and its problems will be described by taking a boom having a three-stage boom and a hydraulic cylinder as an expansion / contraction drive means as an example.
[0004]
The three-stage boom is configured by fitting a two-stage boom body to a first-stage (basic) boom body, and a three-stage (tip) boom body to the two-stage boom body, respectively. It is driven to extend and contract by two hydraulic cylinders.
[0005]
Here, in the conventional crane, generally, when the boom is extended, the two-stage boom body is first extended, and then the three-stage boom body is extended. A sequential operation system is used to reduce the body, and the insertion amount (overlap allowance) between adjacent boom bodies is minimum in the maximum extension state, and the insertion amount is maximum in the minimum reduction state.
[0006]
In some cases, a simultaneous operation system in which both the two- and three-stage boom bodies are extended and contracted at the same time is employed.
[0007]
[Problems to be solved by the invention]
However, with conventional cranes, when the boom is fully extended, it always extends only in a pattern that minimizes the amount of insertion, so it is advantageous in that a high lift can be obtained in normal crane work, but a civil engineering attachment is attached to the boom. During civil engineering work, the amount of insertion is small, so strength and rigidity are insufficient, and boom breakage and fatigue failure may occur.
[0008]
In addition, as a civil engineering specification, it is possible to set the boom maximum extension state so that the amount of insertion becomes large, but this reduces the head during normal crane work, so that the original lifting capacity cannot be utilized.
[0009]
In addition, it is possible to change the amount of insertion according to the time of crane work and civil engineering by manual operation, but the operation is cumbersome and the workability is poor, and the amount of insertion is inevitably varied and fixed. It is difficult to obtain a boom extension state.
[0010]
On the other hand, the crane is equipped with an overload prevention device as standard, and the actual load determined by the boom length and angle and the suspension load exceeds the preset rated total load and is controlled so that it will not fall over or break the machine. Is done.
[0011]
In this case, the strength of the boom changes depending on the insertion amount of the boom bodies (boom extended state) even when the boom length is the same as described above. Therefore, when the insertion amount is changed by manual operation as described above, Accordingly, the rated total load to prevent overload should be set.
[0012]
However, the conventional crane simply detects the boom length and sets the rated total load regardless of the amount of insertion, so this rated total load is set to a value that does not match the actual boom strength. There was a risk of a situation occurring.
[0013]
Therefore, the present invention provides a crane capable of reliably obtaining a boom extension state having an appropriate insertion amount in accordance with the work content and the like.
[0014]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a boom configured such that three or more stages of boom bodies are telescopically fitted to each other, telescopic drive means for extending and retracting the boom, and each stage boom body when the boom is extended. The control means includes a control means for controlling the telescopic drive means in a sequential operation system in which the upper boom body extends after the lower boom body extends, and a mode switching means for switching the boom extension mode. As a boom extension mode for extending the boom, a plurality of types of boom extension modes in which the amount of insertion between adjacent boom bodies in the boom maximum extension state is set in advance, and the boom extension mode selected by the mode switching means is selected. Thus, the expansion / contraction driving means is controlled so as to obtain the insertion amount corresponding to the mode.
[0015]
According to a second aspect of the present invention, in the configuration of the first aspect, the control means is preset with a first boom extension mode with a relatively large insertion amount and a second boom extension mode with a small insertion amount, The mode switching means is configured to switch the boom extension mode between the two modes.
[0016]
According to a third aspect of the present invention, in the configuration of the first or second aspect, the control means includes an operation means for instructing a boom expansion / contraction operation, a detection means for detecting an extension state of the boom, a command signal from the operation means, and the above And a controller for controlling the expansion / contraction driving means in response to a detection signal from the detection means, and the controller detects the boom when the boom is in an extended state corresponding to the boom extension mode selected by the mode switching means. Is configured to stop the boom extension operation based on the detection signal.
[0017]
According to a fourth aspect of the present invention, in the configuration according to any one of the first to third aspects, the control means compares the actual load during work with a preset rated total load and performs an overload prevention operation. A prevention means is provided, and the rated total load is set in accordance with the selected boom extension mode.
[0018]
According to a fifth aspect of the present invention, in the configuration of the fourth aspect, the control means is configured such that the mode switching by the mode switching means is made effective only when the boom is in the minimum contracted state or the vicinity thereof. is there.
[0019]
According to the structure of Claims 1-5, the boom extension mode of the multiple types (two types in Claim 2) from which the insertion amount of boom bodies differs previously is set, the mode selected by the mode switching means, and In order to extend the boom by the sequential operation method, for example, when the crane is operated, the boom is extended in a mode in which the amount of insertion is small (the second boom extension mode in claim 2), thereby maximizing the lifting capacity and working radius. Taking advantage of this, by extending the boom in a mode in which the amount of insertion is large during civil engineering work (the first boom extension mode), it is possible to prevent the boom from being broken or from being damaged due to high boom strength.
[0020]
In other words, depending on the work contents, the boom extension state is changed based on the amount of insertion between the boom bodies, not just the boom length, and the insertion state suitable for the work contents is utilized to maximize the capacity of the crane. It becomes possible.
[0021]
According to the configurations of claims 4 and 5, the rated total load in the overload prevention means provided as standard on the crane is set (changed) according to the amount of insertion. A load preventing effect can be obtained.
[0022]
By the way, in the configuration of claim 4, for example, when the crane is operating in a mode with a small insertion amount (rated total load), if the mode switching means is switched, only the rated total load is set large. On the other hand, even if the mode switching means is switched, the amount of insertion does not change and the boom strength remains in the crane mode. Therefore, the rated total load will be set excessively, and dangers such as breakage of the boom may occur. There is.
[0023]
In this case, it is possible to adopt a configuration in which mode switching is enabled after detecting the insertion amount between each stage boom body, but an insertion amount sensor is required for each stage boom body, which is disadvantageous in terms of cost. The configuration becomes complicated.
[0024]
On the other hand, according to the configuration of the fifth aspect, since the mode switching is made effective only in the vicinity of the boom most contracted, there is no possibility of a discrepancy in the relationship between the rated total load and the actual insertion amount. In addition, since only one sensor that detects the entire length of the boom is required, it is advantageous in terms of cost and the configuration can be simplified.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0026]
1st Embodiment (refer FIGS. 1-4)
1 and 2, reference numeral 1 denotes a crawler type lower traveling body, and 2 denotes an upper revolving body mounted on the lower traveling body 1 so as to be rotatable about a vertical axis. The upper revolving body 2 is provided with an extendable boom 3. Is installed. 4 is a cabin provided in the upper swing body 2, and 5 is a boom hoisting cylinder for hoisting the boom 3.
[0027]
In this embodiment, a three-stage boom is taken as an example.
[0028]
That is, the boom 3 is configured to be telescopic by fitting a two-stage boom body 7 to the first-stage (basic) boom body 6 and a three-stage (tip) boom body 8 to the two-stage boom body 7 in a telescope shape. The two-stage boom body 7 is expanded and contracted by the first hydraulic cylinder 9 provided between the first-stage and second-stage boom bodies 6, 7, and the second-stage boom body 7, 8 provided between the second-stage and third-stage boom bodies 7, 8. The three-stage boom body 8 is configured to extend and contract by the hydraulic cylinder 10.
[0029]
A drive circuit for both the hydraulic cylinders 9 and 10 is shown in FIG.
[0030]
In FIG. 3, reference numeral 11 denotes a hydraulic pump as an operating hydraulic power source for each crane including boom expansion and contraction. Between the hydraulic pump 11 and both hydraulic cylinders 9 and 10, a hydraulic pilot type boom expansion and contraction control valve 12 is provided. The control valve 12 controls the expansion / contraction operation of the cylinders 9 and 10.
[0031]
That is, when the control valve 12 is switched from the neutral position A to the extended position B on the lower side of the figure, the cylinder 9 or 10 is extended, and when the control valve 12 is switched to the reduced position C, both cylinders 9 or 10 are reduced.
[0032]
Here, a switching valve 15 is provided between the control valve 12 and the extension side pipes 13 and 14 of both cylinders 9 and 10.
[0033]
The switching valve 15 is operated by a pilot valve 16 that switches between a two-stage expansion / contraction position (b) and a three-stage expansion / contraction position (b) by a pilot pressure, and operates in response to a signal from a controller, which will be described later. The control valve (solenoid valve) 17 is switched between the two, and at the start of boom extension, the pilot valve 16 is in the two-stage extension position A, the first hydraulic cylinder 9 is extended, and the pilot valve 16 is in the three-stage extension position B. When switched to, the second hydraulic cylinder 10 is extended.
[0034]
Further, when the boom is reduced, the pilot valve 16 is in the three-stage expansion / contraction position B and the second hydraulic cylinder 10 is reduced, and after the cylinder is fully reduced, the pilot valve 16 is switched to the two-stage expansion / contraction position A. 9 is reduced.
[0035]
Reference numeral 18 denotes a pilot hydraulic pressure source of the pilot valve 16.
[0036]
Reference numeral 19 denotes a remote control valve for switching and controlling the control valve 12, and an extension stop valve (electromagnetic valve) 21 controlled by a controller is provided on the extension pilot line 20 of the remote control valve 19.
[0037]
The extension stop valve 21 is set to the open position a when the boom is extended, and is switched to the cutoff position B in response to an extension stop signal from the controller. Thereby, the expansion | extension operation | movement of both the hydraulic cylinders 9 and 10 (boom 3) stops.
[0038]
A tank line 23 connected to the tank T is connected to a spring-side pressure port of the relief valve 22 connected to the discharge circuit of the hydraulic pump 11, and an overload automatic stop valve 24 controlled by a controller is connected to the tank line 23. Is provided.
[0039]
This overload automatic stop valve 24 is in the block position a on the left side of the drawing except during overload, and switches to the open position b on the right side when overload occurs. Thereby, the relief valve 22 performs an unloading action, and the crane operation stops.
[0040]
FIG. 1 shows a boom extension state in which the insertion amounts of the boom bodies are small (insertion amount L1), and FIG. 2 shows a boom extension state in which the insertion amount is large (insertion amount L2). In the state of FIG. Work requiring a work radius (for example, crane work, which will be described in this example) and work requiring high boom strength (for example, civil engineering work, which will be described in this example) are performed in the state shown in FIG.
[0041]
FIG. 4 shows the overall configuration of the control means for switching the insertion amount (boom extension mode) according to the crane work and the civil engineering work and controlling the boom expansion / contraction operation according to the mode change.
[0042]
The control means includes a controller 25, a signal input unit 26 for sending a signal to the controller 25 from the outside, and a valve unit 27 (switching valve 15, extension stop valve 21, overload stop valve 24) controlled by the controller 25. Composed.
[0043]
The signal input unit 26 includes a mode changeover switch 28 for switching the boom extension mode between the crane mode and the civil engineering mode, a boom length meter 29 for detecting the boom length, a boom angle meter 30 for detecting the boom angle, 1 and 2 comprises a pressure detector 31 for detecting the pressure (load) of the boom hoisting cylinder 5 shown in FIGS.
[0044]
Next, the operation of this crane including the operation of the controller 25 will be described.
[0045]
FIG. 4 shows each function of the controller 25 in blocks.
[0046]
Prior to the boom extension operation, either the crane mode or the civil engineering mode is selected by the mode switch 28.
[0047]
Thereafter, when the remote control valve 19 of FIG. 3 is operated to the extension side, the first hydraulic cylinder 9 is first driven by the action of the switching valve 15 and the two-stage boom body 9 starts to extend.
[0048]
On the other hand, based on the signal from the mode changeover switch 28, a mode discrimination A is performed as to whether the crane mode or the civil engineering mode is selected, and the selection B of the insertion amount (L1 or L2) corresponding to the selected mode is performed. Done.
[0049]
Further, based on the selection result of the insertion amount and the result (boom length) of the boom length calculation C based on the signal from the boom length meter 29, the two-stage boom body 7 is selected with the selected insertion amount. A determination D is made as to whether or not the maximum extension state has been reached. If it is determined that the maximum extension state has been reached, the switching valve 15 in FIG. Switch to B.
[0050]
As a result, the extension operation of the two-stage boom body 7 (first hydraulic cylinder 9) stops and the three-stage boom body 8 (second hydraulic cylinder 10) starts the extension operation. When it is determined that the step boom body 8 has reached the maximum extension state, an extension stop signal is sent from the controller 25 to the extension stop valve 21 and the extension operation of the three-stage boom body 8 (second hydraulic cylinder 10) is stopped. To do.
[0051]
As a result, the boom 3 is in the most extended state in the selected mode (the crane mode in FIG. 1 or the civil engineering mode in FIG. 2), and when the crane mode in FIG. As a result, a high boom strength is obtained when the civil engineering mode of FIG. 2 is selected.
[0052]
That is, the boom extension state (boom body insertion amount) according to the work content is automatically obtained, and the crane capacity can be utilized to the maximum.
[0053]
Further, during the work, a boom angle calculation E based on a signal from the boom angle meter 30 and a pressure calculation F based on a signal from the pressure detector 31 are performed, and a work radius calculation G is performed from the boom length and angle. The actual load calculation H is performed from the working radius and pressure.
[0054]
On the other hand, based on the mode discrimination A, the rated total load table I set in advance for each mode is selected I, and the selected rated total load table is collated with the working radius and boom length to check the rated total load. 3 is performed, and if the result of comparison K between the rated total load and the actual load is determined to be an overload, a signal is sent from the controller 25 to the overload automatic stop valve 24 and the relief valve 22 in FIG. Unloading is performed and crane operation stops.
[0055]
In this way, the insertion amount of the boom bodies differs between the crane mode and the civil engineering mode, and the boom strength differs depending on the insertion amount. Therefore, the rated total load for preventing overload is also different for each mode (small value in the crane mode). , Large value in civil engineering mode).
[0056]
As a result, the overload prevention control is performed with the rated total load that is compatible with both modes, so that the rated total load is the same as when the rated total load is set based on the working radius and boom length regardless of the mode. There is no possibility that the crane will be overturned or destroyed when it is set too large, or that the crane capacity will not be utilized because the rated total load is set too low.
[0057]
By the way, if the mode changeover switch 28 is switched to the civil engineering mode during crane work in the crane mode, only the rated total load is set large by the selection I and the calculation J of the rated total load table in the above flow. It will be. On the other hand, the amount of insertion does not change even when the mode changeover switch 28 is switched, and the boom strength remains in the crane mode. Therefore, the rated total load is set excessively, and a dangerous situation such as breakage of the boom occurs. There is a fear.
[0058]
In this case, it is possible to detect the amount of insertion between each stage boom body and then enable mode switching, but this requires an insertion amount sensor for each stage boom body, which is disadvantageous in terms of cost. Become.
[0059]
Therefore, in this embodiment, in the mode discrimination A in FIG. 4, the boom length obtained by the boom length calculation C is taken as a mode discrimination material, and the mode by the mode changeover switch 28 is only in the state where the boom 3 is at the most contracted or close to it. The switching is made valid, and the mode switching is canceled otherwise.
[0060]
With this configuration, there is no possibility of a discrepancy between the relationship between the rated total load and the actual insertion amount. Moreover, since only the boom length meter 29 is required as the sensor, it is advantageous in terms of cost.
[0061]
When the boom is contracted, the three-stage boom body 8 (second hydraulic cylinder 10) is first contracted and the second-stage boom body 7 (first hydraulic cylinder 9) is then operated contrary to the extension, as described above. Reduced operation.
[0062]
Form different from the present invention (see FIG. 5)
In this embodiment, the boom extension mode switching function (insertion amount) as in the first embodiment is not detected, and the boom extension state (insertion amount) is variously changed by the operator's operation, and the insertion amount between the boom bodies is detected. The rated total load is set according to the amount of insertion.
[0063]
More specifically, in addition to the boom angle meter 30 and the pressure detector 31, a cylinder stroke sensor 33 for detecting the strokes of the first and second hydraulic cylinders 9 and 10 is provided as a sensor of the signal input unit 32. A signal is input to the controller 34.
[0064]
In the controller 34, the insertion amount calculation a and the boom length calculation b are performed based on the signal from the cylinder stroke sensor 32, the boom angle calculation c based on the signal from the boom angle meter 30, and the pressure detector. Pressure calculation d based on the signal from 31 is performed.
[0065]
Then, a work radius calculation e is performed from the calculated boom length and boom angle, and an actual load calculation f is performed from the work radius and pressure.
[0066]
On the other hand, the rated total load calculation g is performed by comparing the preset rated total load table for each insertion amount with the working radius and boom length, and a comparison h between the calculated rated total load and the actual load is performed. As a result, when it is determined that there is an overload, a stop signal is sent to the overload automatic stop valve 24 to stop the crane operation.
[0067]
With this configuration, an accurate rated total load corresponding to the amount of insertion between the boom bodies is set, and an appropriate overload preventing action is performed.
[0068]
By the way, in 1st Embodiment, although the structure which switches between two types of boom extension modes, crane mode and civil engineering mode, was taken, the operation | work content is classified more finely and three or more modes (insertion amount). The boom extension mode may be switched with.
[0069]
The present invention is not limited to a three-stage boom, and can be applied to a boom having a four-stage or higher number of stages.
[0070]
【The invention's effect】
As described above, according to the first to fifth aspects of the present invention, in the crane having the telescopic boom composed of three or more boom bodies, a plurality of types of boom extension modes in which the insertion amounts of the boom bodies are different are set in advance. In order to extend the boom in the mode (insertion amount) selected by the mode switching means, for example, by extending the boom in a mode in which the insertion amount is small (second boom extension mode in claim 2) during crane work, Taking advantage of the lifting capacity to maximize the lift and work radius, and extending the boom in the large insertion amount mode (the same as the first boom extension mode) during civil engineering work, the boom is broken and fatigued with high boom strength. Occurrence of destruction can be prevented.
[0071]
In other words, depending on the work contents, the boom extension state is changed based on the amount of insertion between the boom bodies, not just the boom length, and the insertion state suitable for the work contents is utilized to maximize the capacity of the crane. It becomes possible.
[0072]
Further, according to the inventions of claims 4 and 5, since the rated total load in the overload prevention means provided as standard on the crane is set according to the amount of insertion, an accurate overload can be performed under an appropriate rated total load. Preventive action can be obtained.
[0073]
Furthermore, according to the configuration of the fifth aspect, since the mode switching is made effective only in the vicinity of the boom most contracted, there is no possibility that the relation between the rated total load and the actual insertion amount is inconsistent.
[Brief description of the drawings]
FIG. 1 is a side view of a state in which the amount of insertion between boom bodies is reduced in the first embodiment of the present invention.
FIG. 2 is a side view showing a state where the amount of insertion is increased.
FIG. 3 is a diagram showing a configuration of a boom telescopic circuit in the same embodiment.
FIG. 4 is a control block diagram of the same embodiment.
FIG. 5 is a control block diagram of another form different from the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 3 Boom 6 1 step | paragraph boom body 7 2 step | paragraph boom body 8 3 step | paragraph boom body 9 1st hydraulic cylinder as expansion / contraction drive means to extend / contract 2 step | paragraph boom body 10 2nd as expansion / contraction drive means to expand / contract 3 step | paragraph boom body Hydraulic cylinders L1, L2 Insertion amount 15 Switching valve constituting control means 19 Remote control valve as operating means constituting control means 21 Elongation stop valve 24 Overload automatic stop valve constituting overload prevention means among control means 25 Controller constituting control means 28 Mode changeover switch as mode switching means 29 Boom length meter constituting overload prevention means 30 Boom angle meter 31 Same pressure detector 33 Cylinder stroke sensor as insertion amount detection means 34 Control Controller constituting the means

Claims (5)

  A boom having three or more stages of boom bodies fitted telescopically, telescopic drive means for driving the boom to extend and contract, and lower boom bodies of each stage boom body when the boom is extended A control means for controlling the extension / contraction drive means in a sequential operation mode in which the upper boom body extends after extension; and a mode switching means for switching a boom extension mode; and the control means is a boom extension mode for extending the boom. As described above, a plurality of types of boom extension modes with different insertion amounts between adjacent boom bodies in the boom maximum extension state are set in advance, and the modes correspond to the boom extension modes selected by the mode switching means. A crane configured to control the telescopic drive means so as to obtain an insertion amount.   2. The crane according to claim 1, wherein the control means has a first boom extension mode with a relatively large insertion amount and a second boom extension mode with a small insertion amount set in advance, and the mode switching means has a boom extension mode. A crane that is configured to switch between the two modes.   The crane according to claim 1 or 2, wherein the control means includes an operation means for instructing a boom telescopic operation, a detection means for detecting an extension state of the boom, a command signal from the operation means, and a detection signal from the detection means. And a controller for controlling the expansion / contraction drive means, and this controller is based on a detection signal from the detection means when the boom is in an extended state corresponding to the boom extension mode selected by the mode switching means. The crane is configured to stop the extension operation of the boom.   In the crane according to any one of claims 1 to 3, the control means includes an overload prevention means for performing an overload prevention operation by comparing an actual load at the time of work with a preset rated total load, A crane configured to set the rated total load in accordance with a selected boom extension mode.   5. The crane according to claim 4, wherein the control means is configured to enable the mode switching by the mode switching means only when the boom is in a state of being fully contracted or in the vicinity thereof.

Images