JP2011241037A - Boom telescoping step number switching control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress performing a crane operation using an automatic switching means while each movable boom lies in a state different from a regular extension amount.SOLUTION: The boom telescoping step number switching control device includes: automatic switching means S10 automatically switching the movable boom to be telescoped according to a regular boom-telescoping sequence; and manual switching means S20 of manually switching the movable boom to be telescoped. The boom telescoping step number switching control device further includes automatic switching prohibition means S30 of operating the manual switching means S20 and prohibiting the operation of the automatic switching means S10 when the movable boom is telescoped in a sequence different from the regular boom-telescoping sequence. The boom telescoping step number switching control device also includes switching-prohibition release means S40 of operating the manual switching means S20 and releasing the prohibition when the entire telescopic boom has been brought into a maximally retracted or extended state.

Description

  The present invention relates to a boom expansion / contraction stage number switching control device for switching a movable boom to be expanded / contracted among a plurality of movable booms constituting the telescopic boom.

  2. Description of the Related Art Conventionally, there are cranes (machines) provided with telescopic booms such as wheel cranes, rough terrain cranes, all terrain cranes, and the like. The telescopic boom includes a fixed boom on the base end side and a plurality of movable booms provided on the distal end side of the fixed boom. The movable boom is expanded and contracted by a hydraulic cylinder (extensible cylinder). In this type of telescopic boom, it is necessary to select the number of movable booms to be expanded / contracted among a plurality of movable booms constituting the telescopic boom (hereinafter, the number of movable booms to be expanded / contracted is referred to as “selected number of stages”). ).

  Patent Document 1 describes a device that automatically switches the number of selected stages (hereinafter, a mode that automatically switches the number of selected stages is referred to as “automatic switching unit”). In this device, when the telescopic boom is extended, it is extended sequentially from the movable boom on the base end side (thick side). When the telescopic boom is reduced, the telescopic boom is sequentially reduced from the movable boom on the tip side (thin side). Such an order of selection and switching of the number of selected stages is referred to as a “normal boom expansion / contraction order”. In addition, the extension amount (details will be described later) of each movable boom when the movable boom is extended and contracted in the normal boom extension / contraction order is referred to as a “normal extension amount”.

JP-A-9-2781

  The automatic switching means is used during normal crane work. On the other hand, when the telescopic boom is maintained or repaired, a mode in which the operator manually selects the number of selected steps (hereinafter referred to as “manual switching means”) is used. After the maintenance or the like is completed, the crane operation is performed after returning from the manual switching means to the automatic switching means.

  Here, the manual switching means can select the number of selected steps in an order different from the normal boom expansion / contraction order (hereinafter also referred to as “selection error state”). When an arbitrary movable boom is expanded and contracted in the selection error state, each movable boom is in a state different from the normal extension amount (hereinafter also referred to as “different expansion / contraction state”). If the crane work is performed in this state, the following problem occurs.

  A moment limiter is provided in a machine (crane) having a telescopic boom. In the moment limiter, a crane capacity is set on the assumption that each movable boom has a normal extension amount. Therefore, in a state where each movable boom is different from the normal extension amount (different expansion and contraction state), the crane capacity set in the moment limiter does not match the crane capacity that can actually be exhibited. If the crane work is performed in this state, there is a risk of an accident such as breakage of the telescopic boom.

  Therefore, an object of the present invention is to provide a boom expansion / contraction stage number switching control device capable of suppressing the crane work while each movable boom is in a state different from the normal extension amount.

  A boom expansion / contraction stage number switching control device according to a first aspect of the present invention is a control device that switches a movable boom that expands and contracts among a plurality of movable booms constituting the telescopic boom. Automatic switching means for manually switching, and manual switching means for manually switching the movable boom to be expanded and contracted. Furthermore, the automatic switching means is provided that operates the manual switching means and prohibits the operation of the automatic switching means when the movable boom is extended and retracted in an order different from the normal boom expansion and contraction order. Furthermore, the automatic switching prohibition canceling means for canceling the prohibition when the manual switching means is operated and the entire telescopic boom is shortened to the longest is provided.

  The “regular boom expansion / contraction order” refers to the following. When the telescopic boom is extended, the selection stage number is selected and switched so that the movable boom is sequentially extended from the proximal end side to the distal end side. When the telescopic boom is contracted, the selection stage number is selected and switched so that the movable boom is sequentially contracted from the distal end side to the proximal end side.

  The “regular extension amount” described below is the extension amount of each movable boom when the movable boom is expanded and contracted in the regular boom expansion / contraction order. The "regular extension amount" includes not only the extension amount when a plurality of movable booms are actually expanded / contracted according to the regular boom expansion / contraction order, but also the result of expanding / contracting the movable booms without following the regular boom expansion / contraction order, This includes the amount of extension when the same amount of extension (stage orientation) as when the plurality of movable booms were extended or retracted according to the normal boom extension / contraction order.

This boom expansion / contraction step number switching control device includes the automatic switching prohibiting means. Here, when the manual switching means is operated and the movable booms are expanded and contracted in an order different from the normal boom expansion / contraction order, each movable boom may be different from the normal extension amount as described above. In this case, the operation of the automatic switching unit is prohibited by the automatic switching prohibiting unit.
The boom expansion / contraction stage number switching control device includes the automatic switching prohibition canceling unit. Here, when the manual switching means is operated and the entire telescopic boom is shortest or longest, each movable boom always has a normal extension amount. In this case, the prohibition of the operation of the automatic switching means is canceled by the automatic switching prohibition canceling means.
The operator usually operates the automatic switching means to perform crane work. Therefore, as a result of prohibiting the operation of the automatic switching means as described above, the operator is prevented from performing crane work. Therefore, it is possible to suppress the crane work using the automatic switching means while each movable boom may be different from the normal extension amount.

  A boom expansion / contraction stage number switching control device according to a second aspect of the invention includes a movable boom extension amount storage unit that stores extension amounts of the plurality of movable booms. The automatic switching prohibition canceling means is configured such that the extension amount stored in the movable boom extension amount storage means and the normal extension of each of the movable booms when the plurality of movable booms are extended / contracted in the normal boom extension / contraction order. When the amount is all equal, the prohibition is lifted.

  The automatic switching prohibition canceling means of the boom expansion / contraction step number switching control device cancels the prohibition even if the telescopic booms are not the shortest or longest, if each movable boom is a normal extension amount. Therefore, the prohibition can be canceled in a shorter time than when the prohibition is canceled only when the telescopic boom is shortest or longest.

  The boom expansion / contraction stage number switching control device according to a third aspect of the present invention is capable of operating the allowable value of the suspension load set in the moment limiter when the automatic switching prohibiting unit prohibits the operation of the automatic switching unit. An allowable value reducing means for reducing the case is provided.

  This boom expansion / contraction step number switching control device includes the above-described allowable value lowering means. Therefore, when the operation of the automatic switching means is prohibited, that is, when each movable boom is in a state (or a state in which there is a possibility) that is different from the normal extension amount, it is possible to suppress the crane work.

  A boom expansion / contraction stage number switching control device according to a fourth aspect of the present invention is a control device that switches a movable boom that expands and contracts among a plurality of movable booms constituting the telescopic boom, and automatically moves the movable boom that expands and contracts according to a normal boom expansion / contraction order. Automatic switching means for manually switching, manual switching means for manually switching the movable boom to be expanded and contracted, and movable boom extension amount storage means for storing the extension amounts of each of the plurality of movable booms. Further, when the extension amount stored in the movable boom extension amount storage means is different from the normal extension amount of each of the movable booms when the plurality of movable booms are extended / contracted in the normal boom extension / contraction order. Includes an allowable value lowering means for reducing the allowable value of the suspension load set in the moment limiter when all of them are equal.

  In the above configuration, even if the manual switching means is switched to the automatic switching means, if each movable boom is in a state different from the normal extension amount, the allowable value lowering means sets the allowable value of the suspension load set in the moment limiter. Reduce. Therefore, it is possible to suppress the crane work while each movable boom is in a state different from the normal extension amount.

It is a schematic diagram of a telescopic boom and a hydraulic circuit. It is an electric block diagram showing the control apparatus 1 etc. for controlling the hydraulic circuit shown in FIG. It is a flowchart of control by the control apparatus 1 shown in FIG. It is a flowchart of the automatic switching means S10 shown in FIG. FIG. 4 is a diagram corresponding to FIG. 3 of the second embodiment. FIG. 6 is a diagram corresponding to FIG. 3 of the third embodiment. It is FIG. 3 equivalent view of 4th Embodiment. FIG. 6 is a diagram corresponding to FIG. 4 of the fourth embodiment.

(First embodiment)
Hereinafter, (1) a telescopic boom 10 and a hydraulic circuit 20 for expanding and contracting the telescopic boom 10 (see FIG. 1), (2) a control device 1 for controlling the hydraulic circuit 20 (boom telescopic stage number switching control device) The electric system (see FIG. 2) and (3) boom expansion / contraction stage number switching control (see FIGS. 3 and 4) by the control device 1 will be described.

(Extensible boom and hydraulic circuit)
In FIG. 1, the schematic diagram of the telescopic boom 10 and the hydraulic circuit 20 controlled by the control apparatus 1 is shown.

  The telescopic boom 10 is a box-type boom used for a crane, and a plurality of booms are arranged in a nested manner. The telescopic boom 10 includes a fixed boom 11 (also referred to as a basic boom or a one-stage boom) on the base end side attached to a crane body (not shown), and a plurality of movable booms 12 provided on the distal end side of the fixed boom 11. Is provided. The plurality of movable booms 12 are expanded and contracted by a plurality of expansion cylinders 16 and 18.

  The movable boom 12 constitutes the telescopic boom 10 and is a boom that is arranged to be telescopic. The movable boom 12 includes a two-stage boom 12b, a three-stage boom 12c, a four-stage boom 12d, and a five-stage boom 12e in order from the proximal end side to the distal end side. Note that the number of stages of the movable boom 12 may be changed.

The telescopic cylinders 16 and 18 are members that expand and contract each movable boom 12. Each of the telescopic cylinders 16 and 18 is a two-stage telescopic type.
The telescopic cylinder 16 extends and contracts the second-stage boom 12b and the third-stage boom 12c with respect to the fixed boom 11 (first-stage boom). The distal end portion 16a of the telescopic cylinder 16 is fixed to the fixed boom 11, the intermediate portion 16b is fixed to the two-stage boom, and the base end portion 16c is fixed to the three-stage boom 12c.
The telescopic cylinder 18 extends and contracts the 4-stage boom 12d and the 5-stage boom 12e with respect to the 3-stage boom 12c. The distal end portion 18c of the telescopic cylinder 18 is fixed to the three-stage boom 12c, the intermediate portion 18d is fixed to the four-stage boom 12d, and the base end portion 18e is fixed to the five-stage boom 12e.

  The hydraulic circuit 20 expands or contracts a predetermined number of stages among the plurality of movable booms 12. That is, a predetermined number of stages of a predetermined expansion / contraction cylinder is expanded or contracted among the respective stages of the expansion / contraction cylinders 16 and 18. The hydraulic circuit 20 includes a pump 20P that supplies pressure oil to the circuit and a tank 20T that stores hydraulic oil. The hydraulic circuit 20 includes an expansion / contraction switching valve 21 connected to the downstream side of the pump 20P (hereinafter, the downstream side with respect to the pump 20P is simply referred to as “downstream side”), and a cylinder connected to the downstream side of the expansion / contraction switching valve 21. A switching valve 22 and cylinder stage number switching valves 26 and 28 respectively connected to the downstream side of the cylinder switching valve 22 are provided. The telescopic cylinders 16 and 18 are connected to the downstream side of the cylinder stage number switching valves 26 and 28. The hydraulic oil discharged from the expansion / contraction cylinders 16 and 18 returns to the tank 20T via the expansion / contraction switching valve 21.

  The function of each switching valve 21, 22, 26 and 28 is as follows. The expansion / contraction switching valve 21 is a valve that switches between expansion and contraction of the expansion cylinders 16 and 18. The cylinder switching valve 22 is a valve that switches a cylinder to be expanded or contracted among the expansion cylinders 16 and 18. The cylinder stage number switching valves 26 and 28 are valves for switching the number of stages of the expansion cylinders 16 and 18 to be expanded and contracted.

(Electrical system)
FIG. 2 is an electric block diagram around the control device 1 for controlling the hydraulic circuit 20 (see FIG. 1).

  The control device 1 (boom expansion / contraction step number switching control device) is the number of steps of one movable boom 12 to be expanded / contracted among the plurality of movable booms 12 (two-stage boom 12b to five-stage boom 12e) constituting the expansion / contraction boom 10 shown in FIG. Switch (number of selected stages). The control device 1 is specifically an upper crane system controller. That is, the control device 1 may control not only the telescopic boom 10 but also various operations such as raising and lowering the telescopic boom 10, turning an upper swing body (not shown), and hoisting. As shown in FIG. 2, the control device 1 includes switching valves 21, 22, 26, and 28, a boom telescopic operation lever 31, an expansion / contraction switching switch 32, a boom stage number switching permission switch 33, a telescopic boom length detection unit 36, A load detection means 37 and a moment limiter 38 are connected.

  The boom telescopic operation lever 31 instructs expansion / contraction of the telescopic boom 10 (see FIG. 1). When the lever is extended, a boom extension operation signal (PUT) 31 a is output to the control device 1. When the lever is retracted, a boom contracting operation signal (PDT) 31 b is output to the control device 1. The control device 1 outputs a switching signal 21 s to the expansion / contraction switching valve 21 based on the signal input from the boom expansion / contraction operation lever 31. Thereby, the expansion / contraction switching valve 21 is switched.

  The expansion / contraction changeover switch 32 is a switch for switching between the automatic changeover means S10 and the manual changeover means S20 (see FIG. 3, which will be described later), and is provided in a crane cab (not shown). When the automatic switching means S10 (see FIG. 3) is selected, an automatic switching signal 32a is output to the control device 1. When selecting the manual switching means S20 (see FIG. 3), the operator selects the number of selected stages with the expansion / contraction switching switch 32. Then, a manual switching signal 32 b corresponding to the selected number of stages is output to the control device 1.

  The boom stage number switching permission switch 33 is a switch that is pressed when the automatic switching means S10 (see FIG. 3) is operating and permits the switching of the selected number of stages (described later). The boom stage number switching permission switch 33 is, for example, a switch that is attached to the tip (not shown) of the boom extension / contraction operation lever 31 and is pressed while the operator performs a lever operation. When this switch is pressed, a permission signal 33a is output to the control device 1.

  The telescopic boom length detection means 36 is a device that detects the entire length of the telescopic boom 10 (see FIG. 1). The telescopic boom length detection means 36 outputs the telescopic boom length signal 36a corresponding to the detected length to the control device 1.

  The load detection unit 37 is a device that detects a load (suspending load) applied to the telescopic boom 10. The load detection unit 37 outputs a load signal 37 a corresponding to the detected load to the control device 1.

  The moment limiter 38 is a device that prevents the crane from overturning or overloading based on values detected by the telescopic boom length detecting means 36, the load detecting means 37, the boom angle detector (not shown), and the like. In the moment limiter 38, an allowable value such as a suspended load is set on the assumption that each movable boom 12 (see FIG. 1) has a normal extension amount. This allowable value is lowered in a predetermined case (described later). If the value detected by the load detection means 37 is larger than the allowable value, a stop signal 38a is output from the moment limiter 38 to the control device 1 to stop the lifting operation. The telescopic boom length detecting means 36 and the load detecting means 37 may be connected to the control device 1 via a moment limiter 38.

  The cylinder switching valve 22 and the cylinder stage number switching valves 26 and 28 are switched by switching signals 22 s, 26 s, and 28 s output from the control device 1. This switching is controlled as follows.

(Boom telescopic stage number switching control)
3 and 4 show flowcharts of control in the control device 1. The following routine is repeatedly executed every predetermined short time.

  The outline of the boom expansion / contraction step number switching control in the control device 1 is as follows. As shown in FIG. 3, automatic switching means S10 for automatically switching the number of selected stages and manual switching means S20 for manually switching the number of selected stages are provided. When the movable boom 12 (see FIG. 1) is expanded and contracted in the order different from the normal boom expansion / contraction order using the manual switching means S20, the operation of the automatic switching means S10 is prohibited (automatic switching prohibiting means S30). When the entire telescopic boom 10 is made the shortest or longest, the above prohibition is canceled (automatic switching prohibition canceling means S40).

  Step S1 is the first step of boom expansion / contraction step number switching control. In step S1, it is determined whether or not the automatic switching means S10 is selected by the expansion / contraction changeover switch 32 (see FIG. 2) (whether the automatic switching signal 32a is input to the control device 1). (Y) When the automatic switching means S10 is selected, the process proceeds to step S2. (N) When manual switching means S20 is selected, the process proceeds to manual switching means S20. The characters “(Y)” and “(N)” correspond to the characters attached to the flow lines in the flowchart shown in FIG. 3 (the same applies hereinafter).

  In step S2, it is determined whether or not an automatic expansion / contraction switching disable flag F1 (described later) is “OFF”. (Y) When the flag F1 is “OFF” (“OFF” in the initial state), the process proceeds to the automatic switching means S10. (N) When the flag F1 is “ON”, the flow proceeds to the manual switching means S20. That is, even if the operator selects the automatic switching unit S10 with the expansion / contraction changeover switch 32 (see FIG. 2), if the automatic expansion / contraction switching disable flag F1 is “ON”, the automatic switching unit S10 does not operate. Steps S1 and S2 are collectively referred to as step S0, and the case where the process proceeds from step S0 to the manual switching means S20 is denoted as S0a, and the case where the process proceeds from step S0 to the automatic switching means S10 is denoted as S0b.

(Automatic switching means)
The automatic switching means S10 is a mode (routine) for automatically switching the selected number of steps according to a normal boom expansion / contraction order. The automatic switching means S10 is used during normal crane work.

  As shown in FIG. 4, the automatic switching means S10 performs only selection of the number of selected stages (1) immediately after switching from the manual switching means S20 (see FIG. 3) to the automatic switching means S10 (steps S12 and S13). (2) Thereafter, the number of selected stages is also switched (steps S14 to S16). The branch between (1) and (2) is performed in step S11.

  In step S11, it is determined whether or not an automatic expansion / contraction switching control flag F2 (described later) is “ON”. (N) When the flag F2 is “OFF”, the process proceeds to step S12. (Y) When the flag F2 is “ON”, the process proceeds to step S14.

  The automatic expansion / contraction switching control flag F2 operates as follows. The initial state is “OFF”. As shown in FIG. 3, when the manual switching means S20 is operated, it is “OFF” (step S21). Immediately after switching from the manual switching means S20 to the automatic switching means S10, it remains “OFF”. As shown in FIG. 4, the flag F <b> 2 is “ON” during the second and subsequent operations when the automatic switching unit S <b> 10 operates continuously twice or more (step S <b> 13). While the operation of the automatic switching means S10 continues, the “ON” state of the flag F2 also continues.

In step S12, the number of selected stages is determined from the length of the telescopic boom 10 (see FIG. 1) (the telescopic boom length signal 36a (see FIG. 2)). In step S12, it is determined whether or not the following conditions (a) to (d) are satisfied. Judgment is made in the following order (a) to (d). If any of the conditions is met, the number of selected stages described after “:” is selected.
(A) Telescopic boom length <2-stage length + α: Select 2-stage boom 12b (b) Telescopic boom length <3-stage length + α: 3-stage boom 12c selected (c) Telescopic boom length <4-stage Length + α: 4 stage boom 12d is selected (d) Other than above: 5 stage boom 12e is selected Note that the "n stage length" (n = 2 to 4) means the n stage boom and n shown in FIG. This is the total length of the telescopic boom 10 when the movable boom 12 on the proximal end side with respect to the stage boom is made the longest and the movable boom 12 on the distal end side is made the shortest with respect to the n-stage boom. The “α” is, for example, 0.5 m.

  After selecting the selected number of steps in step S12, the process proceeds to step S13 as shown in FIG. 4, and the automatic expansion / contraction switching control flag F2 is set to “ON”. Thereafter, the process proceeds to step S17.

In steps S14 to S16, the following operation is performed.
When the boom stage number switching permission switch 33 (see FIG. 2) is changed from “OFF” to “ON” (when the permission signal 33a rises) ((Y) in step S14), and the telescopic boom 10 (see FIG. 1). ) Becomes the selected step number switching range (described later), the selected step number is switched according to the expansion / contraction direction (step S15).
When the boom stage number switching permission switch 33 (see FIG. 2) does not change from “OFF” to “ON” (step S14 (N)), the selected stage number is not switched (step S16).
In either case, the process proceeds to step S17.

  In this way, the selected stage number is switched only when the boom stage number switching permission switch 33 (see FIG. 2) is operated (in other words, the selected stage number is switched by “semi-automatic”). Therefore, the selection stage number can be switched while reflecting the operator's intention. Note that if the number of selected stages is simply switched automatically, an operation unintended by the operator may occur. For example, when the selected number of stages is switched, the expansion and contraction of the movable boom 12 (see FIG. 1) is decelerated, or the movable booms 12 (see FIG. 1) collide with each other to cause a shock.

  Further, as described above, the boom stage number switching permission switch 33 (see FIG. 2) is provided on the boom telescopic operation lever 31 (see FIG. 2). Therefore, the operation of the boom stage number switching permission switch 33 can be performed together with the operation of the boom extending / contracting operation lever 31. Therefore, the operation efficiency of the operator is not impaired (no operation load is applied).

In step S15, the number of selected stages is determined from the length of the telescopic boom 10 (see FIG. 1) (the telescopic boom length signal 36a (see FIG. 2)). If the length of the telescopic boom 10 (see FIG. 1) is within the selected step number switching range, the selected step number is switched. Specifically, it is determined whether or not the following conditions (a) to (g) are satisfied. The determination is performed in the order of the following (a) to (g). If any of the conditions is met, the number of selected stages described after “:” is selected.
(A) Telescopic boom length <2-stage length-α: Select 2-stage boom 12b (b) Telescopic boom length <2-stage length + α: Switch between 2-stage and 3-stage (c) Telescopic boom length <3 stage length-α: Select 3 stage boom 12c (d) Telescopic boom length <3 stage length + α: Switch between 3 and 4 stages (e) Telescopic boom length <4 stage length-α : 4 stage boom 12d selected (f) Telescopic boom length <4 stage length + α: Switch between 4 stage and 5 stage (g) Other than above: 5 stage boom 12e selected (b) (d) ( As for f), at the time of extension, it is switched to the movable boom 12 (see FIG. 1) on the front end side of the first stage. At the time of reduction, it switches to the movable boom 12 (refer FIG. 1) of the 1st base end side. The “α” is, for example, 0.5 m.

  In step S17, a switching signal corresponding to the number of selected stages selected as described above is output (an output pattern is determined). That is, as shown in FIG. 2, the control device 1 outputs the switching signals 21 s, 22 s, 26 s, and 28 s to the switching valves 21, 22, 26, and 28. Then, the process proceeds to “END” shown in FIG. 3 and the boom expansion / contraction step number switching control routine is terminated.

(Manual switching means)
Manual switching means S20 is a mode for manually switching the number of selected stages as shown in FIG. That is, this is a mode in which the operator arbitrarily selects the number of selected steps. The manual switching means S20 is used during maintenance (or repair, inspection, etc.) of the telescopic boom 10.

The manual switching means S20 operates differently when the expansion / contraction changeover switch 32 (see FIG. 2) selects the manual switching means S20 (1) and when the automatic switching means S10 is selected (2). .
In the case of (1) above, the number of stages selected by the expansion / contraction changeover switch 32 is determined as the selected number of stages. That is, as shown in FIG. 2, the control device 1 outputs the switching signals 21 s, 22 s, 26 s, and 28 s to the switching valves 21, 22, 26, and 28 according to the input manual switching signal 32 b. .
In the case of the above (2) (that is, the automatic switching means S10 shown in FIG. 4 is selected by the expansion / contraction switch 32, but the automatic expansion / contraction switching disabled flag F1 is “ON”. When it does not operate, each switching signal (see FIG. 2) is not output.
In either case (1) or (2), the process proceeds to step S21.

  In step S21, as shown in FIG. 3, the automatic expansion / contraction switching control flag F2 is set to “OFF”. Then, the process proceeds to automatic switching prohibiting means S30.

  The automatic switching prohibiting means S30 is a step for prohibiting the operation of the automatic switching means S10 in a predetermined case (step S31) (step S32).

  In step S31, it is determined whether or not the movable boom 12 (see FIG. 1) has been expanded and contracted in an order different from the normal boom expansion and contraction order (in a selection error state). (Y) When the expansion / contraction operation is performed in the selection error state, the process proceeds to step S32, and the automatic expansion / contraction switching disable flag F1 is set to “ON”. That is, the automatic switching means S10 is not operated as it is. Thereafter, the process proceeds to automatic switching prohibition releasing means S40. (N) When the expansion / contraction operation in the selection error state is not performed (when the expansion / contraction operation is not performed, or when the expansion / contraction operation is performed but the normal boom expansion / contraction order is followed), the process proceeds to the automatic switching prohibition release unit S40.

  Further, the determination as to whether or not the selection error state has occurred in step S31 is made by comparing the number of selected steps (the number of manually selected steps) with the length of the telescopic boom 10. That is, if the number of selected stages to be selected in step S12 (see FIG. 4) is different from the number of manually selected stages, it is determined that a selection error state has occurred. In the selection error state, in principle, the moment limiter 38 (see FIG. 2) automatically stops the expansion / contraction operation (a stop signal 38a shown in FIG. 2 is output to the control device 1). However, if the automatic stop release switch (not shown) provided in the moment limiter 38 is set to “release”, the movable boom 12 (see FIG. 1) can be expanded and contracted even in a selection error state.

  The automatic switching prohibition canceling means S40 cancels the prohibition (step S42) in a predetermined case (step S41).

  In step S41, it is determined whether the telescopic boom 10 (see FIG. 1) is set to the shortest (basic length) or the longest using the manual switching means S20. (Y) If it is set to the shortest or longest, the process proceeds to step S42, and the automatic expansion / contraction switching disable flag F1 is set to “OFF”. That is, the prohibition of the operation of the automatic switching means S10 is canceled. Then proceed to “END”. (N) If the telescopic boom 10 is neither the shortest nor the longest, proceed to “END”.

(Features of the boom expansion / contraction step number switching control device of the present embodiment)
As shown in FIG. 3, the control device 1 includes automatic switching prohibiting means S30. Here, when the manual switching means S20 is operated and the movable booms 12 (see FIG. 1) are expanded / contracted in an order different from the normal boom expansion / contraction order (in a selection error state), each movable boom 12 has a normal extension amount. May be different (different stretch state). In this case, the operation of the automatic switching unit S10 is prohibited by the automatic switching prohibiting unit S30 (step S32).

  In addition, the control device 1 includes automatic switching prohibition releasing means S40. Here, when the manual switching means S20 is operated and the entire telescopic boom 10 is made the shortest or longest, each movable boom 12 always has a normal extension amount. In this case, the automatic switching prohibition canceling means S40 cancels the prohibition of the operation of the automatic switching means S10 (step S42).

  In addition, the operator usually operates the automatic switching means S10 (to leave the machine to do so) to perform the crane work. Therefore, as described above, the operation of the automatic switching means S10 is prohibited (step S32). As a result, the operator is easily aware of the different expansion and contraction states, and the crane work is suppressed. Therefore, the crane work is performed using the automatic switching means S10 while each movable boom 12 may be different from the normal extension amount (a state where there is a possibility of different expansion and contraction) (the operator makes a mistake) Can be suppressed.

(Second Embodiment)
FIG. 5 shows a flowchart (corresponding to FIG. 3) of the second embodiment. Differences from the first embodiment are as follows. A movable boom extension amount storage unit S250 that stores the extension amount of each movable boom 12 (see FIG. 1) and a step S245 for correcting the extension amount are provided. Further, when the automatic switching prohibition releasing means S240 is different from the different expansion / contraction state (step S246), the automatic switching means S10 can be operated (step S42).

  In the movable boom extension amount storage means S250, the extension amounts of the plurality of movable booms 12 (see FIG. 1) are stored. This extension amount is obtained based on the change in the entire length of the telescopic boom 10 (see FIG. 1) (change in the telescopic boom length signal 36a shown in FIG. 2) and the number of selected stages. The movable boom extension amount storage means S250 is also executed when the automatic switching means S10 is passed (that is, when there is no different expansion / contraction state). In this case, the extension amount of the selected step number may be obtained by subtracting the length of the movable boom 12 (see FIG. 1) on the base end side from the selected step number from the entire length of the telescopic boom 10. Then, the process proceeds to automatic switching prohibition canceling means S240.

  In step S245, when the length of the telescopic boom 10 (see FIG. 1) is the shortest or longest (step S41), the extension amount of each movable boom 12 (see FIG. 1) stored in the movable boom extension amount storage means S250. Correct. (1) When the length of the telescopic boom 10 (see FIG. 1) is maximized, the extension amount of all the stages of the movable boom 12 (see FIG. 1) is set to 100% of the length of each movable boom 12. (2) When the length of the telescopic boom 10 is minimized, the extension amount of all the stages of the movable boom 12 is set to 0% of the length of each movable boom 12. In either case (1) or (2), the process proceeds to step S246.

  In step S246, it is determined whether or not a different stretched state. That is, it is determined whether or not the extension amount of each movable boom 12 (see FIG. 1) stored in the movable boom extension amount storage means S250 is equal to the normal extension amount.

  Specifically, the determination as to whether or not a different stretch state is made is performed as follows. The extension amount of each movable boom 12 (see FIG. 1) stored in the movable boom extension amount storage means S250 is examined in order from the proximal end side to the distal end side. If the extension amount exceeds a predetermined amount (for example, 0.5 m) in the step on the tip side of the step where the extension amount is not 100% (± α (α is, for example, 0.5 m)), the stretched state is different. Judge. (Y) If there is no different expansion / contraction state, the process proceeds to step S42, and the automatic expansion / contraction switching impossibility flag F1 is set to “OFF” to cancel the prohibition of the operation of the automatic switching means S10. maintain). Then proceed to “END”. (N) If there is a different expansion / contraction state, proceed directly to “END”.

(Characteristics of the boom expansion / contraction stage number switching control device of the second embodiment)
The automatic switching prohibition canceling means S240 of the control device 1 automatically switches when each movable boom 12 has a normal extension amount even if the telescopic boom 10 (see FIG. 1) is not the shortest or longest (step S246). The prohibition of the operation of the means S10 is canceled (step S42). Therefore, the prohibition can be canceled in a shorter time than when the prohibition of the operation of the automatic switching means S10 is canceled only when the telescopic boom 10 (see FIG. 1) is the shortest or longest.

(Third embodiment)
FIG. 6 shows a flowchart (corresponding to FIG. 3) of the third embodiment. Differences from the second embodiment are as follows. In the automatic switching prohibition releasing means S340, when there is a different expansion / contraction state (step S246), the suspension load is interlocked (allowable value lowering means S351). When there is no different expansion / contraction state, the interlock is released (step S352).

  In step S246 of the automatic switching prohibition canceling means S340, if there is a (N) different expansion / contraction state, the process proceeds to the allowable value lowering means S351. (Y) When there is no different expansion / contraction state, the process proceeds to step S42.

  In the allowable value lowering means S351, the suspension load is interlocked in the case of the different expansion / contraction state (step S246 (N)). That is, the allowable value of the suspension load set in the moment limiter 38 (see FIG. 2) is lowered with respect to the case where the automatic switching means S10 is operable (not in a different expansion / contraction state) (the moment limiter 38 shown in FIG. 2). To output an allowable value lowering instruction signal 338b to the control device 1). As shown in FIG. 6, the allowable value of the suspended load is specifically set to 0t, for example. Thereby, the crane operation | work which hangs a suspended load cannot be performed reliably. The possible work is limited to the expansion and contraction of the telescopic boom 10 (see FIG. 1). In addition, you may set the allowable value of a suspension load to the fixed value of the level which does not cause the damage of the telescopic boom 10 (refer FIG. 1).

  In step S352, when it is not in the different expansion / contraction state (step S246 (Y)), the suspension load allowable value set in the moment limiter 38 (see FIG. 2) is returned to normal (in the case where it is not in the different expansion / contraction state).

(Characteristics of the boom expansion / contraction stage number switching control device of the third embodiment)
The control device 1 includes an allowable value lowering unit S351. Therefore, when the operation of the automatic switching means S10 is prohibited, that is, when each movable boom 12 (see FIG. 1) is in a state different from the normal extension amount (different expansion / contraction state) or a state in which there is a possibility, the suspension is suspended. It is possible to suppress the crane work for hanging the load.

  As described above, when the operation of the automatic switching means S10 is prohibited, as a result, the operator notices a different expansion / contraction state, and the crane work in the different expansion / contraction state is suppressed. On the other hand, in the automatic switching means S10 of the present embodiment, it is possible to suppress the crane work for hanging a suspended load in a different stretched state regardless of the operator's intention.

(Fourth embodiment)
7 and 8 show a flowchart (corresponding to FIGS. 3 and 4) of the fourth embodiment. Differences from the third embodiment are as follows. As shown in FIG. 7, the present embodiment does not include automatic switching prohibiting means S30 (see FIG. 3). That is, if the automatic switching means S410 is selected by the expansion / contraction changeover switch 32 (see FIG. 2), the automatic switching means S410 operates. The operation of the automatic switching means S410 is different from that of the automatic switching means S10 (see FIG. 4). Further, in the automatic switching prohibition release means S440, when there is no different expansion / contraction state (step S246), the automatic expansion / contraction switching control flag F2 is set to “ON” (step S442).

  Automatic switching means S410 operates as follows. As shown in FIG. 8, (1) when in a different telescopic state (step S11 (N)), the number of selected stages is determined regardless of the length of the telescopic boom 10 (see FIG. 1) (steps S418, S419a, and S419b). (2) When it is not in a different telescopic state (step S11 (Y)), the number of selected stages is determined based on the length of the telescopic boom 10 (see FIG. 1) (steps S14 to S16). The above (1) and (2) branch at step S11.

  In step S11, it is determined whether or not the automatic expansion / contraction switching control flag F2 is “ON”. (N) When the flag F2 is “OFF”, that is, when it is in a different expansion / contraction state (see step S442 shown in FIG. 7), the process proceeds to step S418. (N) When the flag F2 is “ON”, that is, when it is not in the different expansion / contraction state, the process proceeds to step S14.

  In step S418, it is determined whether the expansion / contraction operation is expansion or contraction. (N) If it is a reduction operation, the process proceeds to step S419a. (Y) If it is an extension operation, the process proceeds to step S419b.

In step S419a, the selection stage number is selected in order from the movable boom 12 (see FIG. 1) on the distal end side, regardless of the length of the telescopic boom 10 (see FIG. 1). When the movable boom 12 (refer to FIG. 1) that has been contracted no longer contracts (when it is detected that the telescopic boom length signal 36a (refer to FIG. 2) does not change), Select a stage.
Specifically, it is as follows. As shown in FIG. 1, first, the five-stage boom 12e which is the movable boom 12 at the most distal end side is first contracted. If the length does not change for a predetermined time because the fifth-stage boom 12e is completely reduced, the fourth-stage boom 12d is then reduced. Such switching is sequentially performed from the distal end side to the proximal end side. Then, the process proceeds to step S17.

  In step S419b, regardless of the length of the telescopic boom 10 (see FIG. 1), the number of selected steps is selected in order from the proximal-side movable boom 12 (see FIG. 1). Then, when the extending movable boom 12 (see FIG. 1) does not extend, the first step is selected. That is, the operation opposite to that in step S419a is performed. Then, the process proceeds to step S17.

(Characteristics of the boom expansion / contraction step number switching control device of the fourth embodiment)
Even if the manual switching means S20 shown in FIG. 7 is switched to the automatic switching means S410, the control device 1 is in a state where each movable boom 12 (see FIG. 1) is different from the normal extension amount (in different telescopic states). If not (step S246), the allowable value lowering means S351 decreases the allowable value of the suspension load set in the moment limiter 38 (see FIG. 2). Therefore, it is possible to suppress the crane work while each movable boom 12 (see FIG. 1) is in a state different from the normal extension amount (a different stretched state).

(Modification)
The control device 1 may be combined with other devices. For example, a display device (not shown) that displays in the cab that each movable boom 12 (see FIG. 1) is in a state (different expansion / contraction state) different from the normal extension amount or that the different expansion / contraction state has been eliminated. You may add to said structure. In this case, the operator can know the presence / absence of the different expansion / contraction state. Therefore, it is possible to further suppress normal crane work while in a different stretched state.

  The number of stages of the telescopic boom 10 shown in FIG. 1 can be variously changed. Moreover, you may provide not only the movable boom 12 expanded and contracted with the expansion cylinders 16 and 18, but the movable boom expanded and contracted with an expansion / contraction wire rope (not shown). Specifically, for example, a 6-stage boom and a 7-stage boom that are simultaneously expanded and contracted by an extendable wire rope (not shown) may be attached to the distal end side of the 5-stage boom 12e. In this case, the control of the above embodiment is performed for the second-stage boom 12b to the fifth-stage boom 12e (see FIG. 1).

1 Control device (Boom telescopic stage number switching control device)
DESCRIPTION OF SYMBOLS 10 Telescopic boom 12 Movable boom 38 Moment limiter S10, S410 Automatic switching means S20 Manual switching means S30 Automatic switching prohibition means S40, S240, S340 Automatic switching prohibition release means S250 Movable boom extension amount storage means S351 Allowable value lowering means

Claims (4)

A boom selection stage number switching control device for switching the movable boom to be expanded and contracted among a plurality of movable booms constituting the telescopic boom,
Automatic switching means for automatically switching the movable boom to be expanded and contracted according to a normal boom expansion and contraction order;
Manual switching means for manually switching the movable boom to be expanded and contracted;
Automatic switching prohibiting means for prohibiting the operation of the automatic switching means when operating the manual switching means and extending and retracting the movable boom in a different order from the regular boom expansion and contraction order;
A boom expansion / contraction stage number switching control device comprising: an automatic switching prohibition canceling unit that operates the manual switching unit and cancels the prohibition when the entire telescopic boom is shortest or longest. Movable boom extension amount storage means for storing the extension amount of each of the plurality of movable booms;
The automatic switching prohibition canceling means is configured such that the extension amount stored in the movable boom extension amount storage means and the normal extension of each of the movable booms when the plurality of movable booms are extended / contracted in the normal boom extension / contraction order. The boom expansion / contraction stage number switching control device according to claim 1, wherein the prohibition is canceled when the amounts are all equal.   When the operation of the automatic switching unit is prohibited by the automatic switching prohibiting unit, an allowable value lowering unit that decreases the allowable value of the suspension load set in the moment limiter with respect to the case where the operation is possible is provided. Item 3. The boom expansion / contraction step number switching control device according to Item 1 or 2. A boom expansion / contraction stage number switching control device for switching the movable boom to be expanded / contracted among a plurality of movable booms constituting the telescopic boom,
Automatic switching means for automatically switching the movable boom to be expanded and contracted according to a normal boom expansion and contraction order;
Manual switching means for manually switching the movable boom to be expanded and contracted;
Movable boom extension amount storage means for storing an extension amount of each of the plurality of movable booms;
When the extension amount stored in the movable boom extension amount storage means is different from the normal extension amount of each of the movable booms when the plurality of movable booms are extended / contracted in the normal boom extension / contraction order, A boom expansion / contraction stage number switching control device comprising: an allowable value reducing means for reducing an allowable value of the suspension load set in the moment limiter when all of them are equal.

Images