JP2003026393A - Hook lowering length keeping device of crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hook lowering length keeping device capable of keeping constant the lowering length L of a hook 11 by joint use of the boom telescopic motion and the winch lowering and hoisting motion. SOLUTION: A controller 19 controls switching of an expansion and contraction control valve 4 according to a control signal 19a for the expansion and contraction control valve obtained from an expansion and contraction operating signal (a). On the other hand, according to the expansion and contraction operating signal (a), a boom length detecting signal La, and a let-out length detecting signal Sa, a valve switching direction and a valve switching amount δs required to obtain the conformity of the fluctuation L-L0 of the boom length L with the fluctuation S-S0 of the actual wire let-out length are obtained, and the switching of the winch control valve 7 is controlled according to a control signal 19b of the winch control valve.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hook hanging length holding device for holding a hook hanging length constant when extending and retracting a telescopic boom of a crane. It is about. 2. Description of the Related Art First, referring to FIGS. 2 and 3, the construction of a crane to which a hook hanging length holding device is mounted will be described by taking a truck-mounted crane as an example. FIG. 2 is an overall configuration diagram of a truck-mounted crane, and FIG. 3 is an explanatory diagram of a drive hydraulic circuit of a telescopic boom and a winch device. As shown in FIG. 2, a truck-mounted crane includes a swivel post 2 pivotally mounted on a base 1 and a swivel post mounted on the swivel post 2 so as to be movable forward and backward in a base end boom section 3a. Boom sections 3b, 3c, 3d
Telescopic boom 3 with telescopically inserted therein, telescopic boom 3
Proximal boom section 3a and distal boom section
First and second telescopic cylinders 5 and 6, and a winch control valve 7, which are interposed between 3b and between the end side boom sections 3 b and 3 c, respectively, and extend and retract the boom 3 by being driven by the control oil from the telescopic control valve 4. A winch device 9 driven up and down by a winch motor 8 driven forward and reverse by control oil from
And the wire rope 10 fed from the winch device 9
And a hook 11 suspended from the distal end of the telescopic boom so as to be able to hoist and lower. [0004] Between the distal end boom section 3c and 3d, a conventionally known wire rope simultaneously driven to extend and retract the distal end boom section 3d in conjunction with the extension and contraction movement of the distal end boom section 3c by the second telescopic cylinder 6. Telescopic mechanism C
Is installed. For this reason, even if the pressure receiving areas of the extension-side oil chambers of the first and second telescopic cylinders 5 and 6 are the same,
The expansion and contraction speed of the telescopic boom 3 is different from the expansion and contraction speed of the first telescopic cylinder 5 in the expansion and contraction operation range (the expansion and contraction speed of the boom section 3 b). ) Expands and contracts at twice the speed. In FIG. 3, reference numeral 12 denotes a sequential telescopic control valve interposed between the telescopic control valve 4 and the first and second telescopic cylinders 5, 6, and the sequential telescopic control valve 12 is used to drive the telescopic cylinder to extend. Sometimes, the second telescopic cylinder 6 is extended after the first telescopic cylinder 5 is fully extended, and the valve device for sequentially driving the first telescopic cylinder 5 to be contracted after the second telescopic cylinder 6 is fully contracted during the contraction drive. is there. The truck-mounted crane thus configured suspends the luggage on the hook 11 suspended from the distal end of the telescopic boom 3 to extend and retract the telescopic boom 3 and to raise and lower the winch device 9. The lowering drive drives the luggage to an arbitrary position and performs crane work. In this type of crane, the hook 11 is suspended from the end of the telescopic boom as described above. Therefore, when the boom is extended, the hook 11 rises and approaches the end of the boom. 11 descends and approaches the ground. For this reason, the operator lowers the winch device 9 simultaneously with the extension operation of the telescopic boom 3 or raises the winch device 9 simultaneously with the contraction operation of the telescopic boom 3, so that the telescopic boom 3 can be moved. Irrespective of this, the interlocking operation was performed so that the suspension length L of the hook 11 from the boom tip (the distance between the tip of the telescopic boom 3 and the upper end of the hook 11) did not change. This interlocking operation is complicated and imposes a burden on the worker, and automation has been desired. For this reason, the winch device 9 is driven down and hoisted in conjunction with the expansion and contraction movement of the telescopic boom 3, and the telescopic boom 3 is driven.
A so-called hook suspension length holding device has been developed which automatically controls the suspension length L of the hook 11 so as not to vary irrespective of the expansion / contraction movement of the hook. A conventional hook suspension length holding device is disclosed in Japanese Patent Application Laid-Open No. 2000-344472, for example, in which the actual switching control amount a of the telescopic control valve 4 (the telescopic control valve 4
And the switching control amount b of the winch control valve 7 for preventing the hook hanging length L from fluctuating when the telescopic boom 3 expands and contracts. Is changed depending on which of the first and second telescopic cylinders 5 and 6 the telescopic boom 3 is in the telescopic operation range, and the switching control amount b of the winch control valve 7 is changed to the telescopic control valve. 4 based on the actual switching control amount a and the telescopic stage detection signal d from the telescopic stage number detector 13 for detecting which of the first and second telescopic cylinders 5 and 6 is in the telescopic operation range. It was to be calculated. However, in the conventional hook suspension length holding device, the relationship between the telescopic control valve 4 and the switching control amounts a and b of the winch control valve 7 is determined by the telescopic boom 3. A predetermined relationship (telescopic boom 3) preset for each telescopic operation area
The relationship for controlling the hook suspension length L to be constant regardless of the expansion / contraction operation area of the hook) can maintain the hook suspension length L approximately constant.
Since it is not configured to detect the actual fluctuation amount of the hook suspension length L and correct the switching control amount of the winch control valve 7, it is difficult to accurately maintain the hook suspension length L accurately. There was a problem that is. Also, there is a problem that the number of expansion / contraction stages detecting means 13 is required. SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the conventional hook suspension length holding device, and it is possible to accurately control the hook suspension length to be constant, and to detect the number of expansion / contraction steps. It is an object of the present invention to provide a hook hanging length holding device that does not require a hook. [0014] The present invention has the following configuration as means for solving the above-mentioned problems. That is, the hook hanging length holding device of the crane according to the present invention comprises a swivel post pivotally mounted on a base, a telescopic boom mounted up and down on the pivot post, and a telescopic control valve. First and second telescopic cylinders driven by control oil to sequentially extend and retract the telescopic boom, and are driven up and down by a winch motor driven by control oil from a winch control valve to the turning post or telescopic boom base end. A winch device attached thereto, and a hook suspended from the distal end of the telescopic boom so as to be able to be lifted and lowered by a wire rope pulled out from the winch device. The extension and contraction speed of the boom is different between the extension and contraction operation range of the first extension and contraction cylinder and the extension and contraction operation range of the second extension and contraction cylinder. Directed to a hook hanging length holding device over emissions. The hook suspension length holding device according to the present invention includes a telescopic operating means for outputting a telescopic operation signal for instructing a valve switching direction and a valve switching amount of the telescopic control valve, and an actual boom length of the telescopic boom. Boom length detecting means for detecting and outputting a boom length detection signal, wire feeding length detecting means for detecting the actual feeding length of the wire rope and outputting a feeding length detection signal, and A controller that receives an extension / contraction operation signal, a boom length detection signal, and a delivery length detection signal, and that outputs a control signal for switching control of an extension / contraction control valve and a winch control valve. Based on the operation signal, a telescopic control valve control signal for switching the telescopic control valve to a valve switching direction and a valve switching amount indicated by the telescopic operation signal is generated, and the telescopic control valve control signal is generated. To output. (2) Based on the telescopic operation signal, the boom length detection signal and the payout length detection signal, the fluctuation amount of the boom length detection signal and the fluctuation amount of the actual wire payout length after receiving the telescopic operation signal are calculated. A winch control valve control signal for switching the winch control valve to the valve switching direction and the valve switching amount is determined by determining a valve switching direction and a valve switching amount of the winch control valve necessary for making the winch control valve coincide with each other. The control signal is output to the winch control valve. It is configured as follows. With this configuration, the controller first outputs the telescopic control valve control signal based on the telescopic operation signal from the telescopic operation means, and switches the telescopic control valve to the valve switching direction indicated by the telescopic operation signal. Switch to the switching amount. The control oil from the telescopic control valve switched by the telescopic control valve control signal is supplied to the first and second telescopic cylinders to drive the telescopic boom to telescopic. At this time, the expansion / contraction speed of the telescopic boom is set to be different between the telescopic operation range of the first telescopic cylinder and the telescopic operation range of the second telescopic cylinder. On the other hand, simultaneously with the switching of the telescopic control valve, the controller outputs a winch control valve control signal as follows to control the switching of the winch control valve. That is, when the controller receives the telescopic operation signal based on the telescopic operation signal from the telescopic operation means, the boom length detection signal from the boom length detection means, and the extension length detection signal from the wire extension length detection means, Obtain the valve switching direction and valve switching amount of the winch control valve necessary to match the fluctuation amount of the subsequent boom length detection signal with the fluctuation amount of the actual wire feeding length, and set the winch control valve to the valve switching direction. A winch control valve control signal for switching to the valve switching amount is generated, and the winch control valve control signal is output to the winch control valve to switch and control the winch control valve. Then, the control oil from the winch control valve switched by the winch control valve control signal is supplied to the winch motor so as to drive down and hoist the winch device so that the hanging length of the hook is maintained constant. Has become. At this time, the telescopic boom varies in the telescopic speed depending on the telescopic operating range of the telescopic cylinder even if the telescopic operation signal is constant as described above. This is detected as a difference in the amount of change in the actual boom length per unit time. For this reason, the actual boom length detected by the boom length detection means is detected by incorporating the difference in the expansion / contraction speed due to the expansion / contraction operation range of the telescopic cylinder, and the fluctuation amount of the boom length and the wire feeding length are detected. The valve switching direction and the valve switching amount of the winch control valve are determined so as to match the actual wire feeding length fluctuation amount detected by the detecting means, and the winch control valve is switched by the control signal to wind the winch device. If the lower hoisting drive is performed, the hook suspension length holding control can be performed very accurately by so-called feedback control. In addition, the hook suspension length holding device configured as described above,
Unlike the conventional hook suspension length holding device, there is no need for a means for detecting the number of expansion and contraction steps, and the configuration is simplified. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific configuration of the present invention will be described with reference to FIG. Incidentally, the hook suspension length holding device of the present invention is adapted to the drive hydraulic circuit of the telescopic boom and winch device described as the prior art,
In the following description, 1 to 12 described as the entire configuration of the crane and the drive hydraulic circuit, and the reference numerals C and L have the same meaning, and a detailed description thereof will be omitted. In FIG. 1, reference numeral 15 denotes a hook suspension length holding device. The hook suspension length holding device 15 is a telescopic operation signal a for instructing a valve switching direction and a valve switching amount of the telescopic control valve 4.
, A boom length detecting means 17 for detecting the actual boom length L of the telescopic boom 3 and outputting a boom length detection signal La, and an actual feeding length S of the wire rope 10. Wire feeding amount detecting means 18 for detecting and outputting a feeding length detection signal Sa, and receiving expansion / contraction operation signal a, boom length detection signal La and feeding length detection signal Sa from each of these means 16, 17, 18 It comprises a controller 19 for outputting a valve control signal for switching control of the telescopic control valve 4 and the winch control valve 7. The boom length detecting means 17 is for continuously detecting the distance between the front end boom section 3d and the base end boom section 3a. The end of the cord fed from the winder is fastened to the tip of the boom section 3d at the foremost end, and the amount of cord fed out in conjunction with the telescopic movement of the telescopic boom 3 is determined. It is constituted by a conventionally known cord winder with a feeding amount detecting function for electrically detecting by using a potentiometer or the like. The wire feeding length detecting means 18 includes:
It continuously detects the length of the wire rope 10 fed from the winch device 9.
It is constituted by rotation detecting means for electrically detecting the number of rotations of the drum of the winch device 9 on which the 10 has been wound using a rotary encoder or the like. Further, the controller 19 includes a telescopic operation signal a from the telescopic operating means 16, a boom length detection signal La from the boom length detecting means 17, and a feeding length detection from the wire feeding length detecting means 19. Receiving each signal of the signal Sa,
The arithmetic processing is performed as follows. That is, reference numeral 20 denotes an expansion / contraction control valve control signal output section incorporated in the controller 19, and the expansion / contraction control valve control signal output section 20 outputs the expansion / contraction control signal based on the expansion / contraction operation signal a from the expansion / contraction operation means 16. The valve 4 is set to the telescopic operation signal a
Generates a telescopic control valve control signal 19a for switching to the valve switching direction and the valve switching amount indicated by the command, and outputs this signal 19a to the valve switching means 4a of the telescopic control valve 4. Thus, the expansion / contraction control valve 4 is controlled to switch to the valve switching direction and the valve switching amount corresponding to the expansion / contraction operation signal a.
Is supplied to the first telescopic cylinder 5 and the second telescopic cylinder 6, and the telescopic boom 3 is driven to expand and contract.
At this time, the telescopic control valve control signal output unit 20 calculates the telescopic control valve control signal 19a based on the telescopic operation signal a (valve switching amount). Control signals of the same level are output. For this reason, the telescopic boom 3 expands and contracts at a speed twice as long as the telescopic operation range of the second telescopic cylinder 6 with respect to the telescopic operation range of the first telescopic cylinder 5. Reference numeral 21 denotes an initial boom length storage unit for storing the boom length L0 detected by the boom length detection means 17 at the time when the expansion / contraction operation signal a is input. Is an initial wire feeding length storage unit for storing the feeding length S0 detected by the wire feeding length detecting means 18 at the point in time when is input. A boom 23 calculates a difference L-L0 between the initial boom length L0 stored in the initial boom length storage section 21 and the boom length L currently detected by the boom length detecting means 17. Reference numeral 24 denotes a length variation calculating unit, which is configured to calculate the initial wire feeding length S0 stored in the initial wire feeding length storage unit 22 and the wire feeding length S currently detected by the wire feeding length detecting unit 18. This is a wire feeding length variation calculating unit for calculating the difference S-S0. Reference numeral 25 denotes the boom length variation calculating section 23.
And the wire feeding length variation S- calculated by the wire feeding length variation calculating unit 24.
This is a valve switching amount calculation unit for obtaining the valve switching direction and the valve switching amount δS of the winch control valve 7 necessary for matching S0. Reference numeral 26 denotes a winch control valve control signal output unit. The winch control valve control signal output unit 26 is configured to control the winch control valve 7 based on the valve switching direction and the valve switching amount δS from the valve switching amount calculation unit 25. Generates a winch control valve control signal 19b for switching the valve switching direction and the valve switching amount δS,
This signal 19b is output to the valve switching drive means 7a of the winch control valve 7. As a result, the winch control valve 7 is switch-controlled by the valve switching direction and the valve switching amount δS calculated by the valve switching amount calculator 25, and the control oil from the winch control valve 7 is supplied to the winch motor 8 to control the winch device. 9
Are driven down and up. At this time, the expansion / contraction speed of the telescopic boom 3 varies between the telescopic operation range of the first telescopic cylinder 5 and the telescopic operation range of the second telescopic cylinder 6 even if the telescopic operation signal a is constant as described above. However, the difference in the expansion / contraction speed of the telescopic boom 3 is detected by the boom length detecting means 17 as the difference in the amount of change in the actual boom length L per unit time. For this reason, the detected fluctuation amount of the boom length L is detected by incorporating the difference in the expansion and contraction speed between the first and second telescopic cylinders 5 and 6 according to the expansion and contraction operation areas. Of the actual wire feeding length SS detected by the wire feeding length detecting means 19 and the fluctuation amount L−L0
The winch control valve 7 is switched to the valve switching direction and the valve switching amount δS by obtaining the valve switching direction and the valve switching amount δS of the winch control valve 7 so as to match 0, and the winch device 9 is driven down and hoisted. For example, the hook suspension length holding control can be performed very accurately by the so-called feedback control. According to the hook hanging length holding device of the crane of the present invention configured as described above, the telescopic boom 3 in which the telescopic speed of the telescopic boom 3 is different depending on the telescopic operation range of the first and second telescopic cylinders. Even with a crane equipped with a hook, the hook suspension length holding control can be performed very accurately by the feedback control. Further, the hook hanging length holding device configured as described above has an effect of not requiring the number of expansion / contraction stages detecting device unlike the conventional device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view of a hook hanging length holding device of a crane of the present invention. FIG. 2 is an explanatory view of a crane for mounting the hook hanging length holding device of the present invention. FIG. 3 is an explanatory diagram of a telescopic boom of a crane and a drive hydraulic circuit of a winch device. [Description of Signs] 1; base, 2; swivel, 3; telescopic boom, 4; telescopic control valve, 5; first telescopic cylinder, 6; second telescopic cylinder, 7; winch control valve, 8; winch motor , 9; winch device, 10; wire rope, 11; hook, 15; hook hanging length holding device, 16; telescopic operation device, 17; boom length detecting device, 18; wire feeding amount detecting device, 19; controller 20; telescopic control valve control signal output unit; 21; initial boom length calculating unit; 22; initial wire feeding length storage unit; 23; boom length variation calculating unit; 24; wire feeding length variation calculating unit , 25; valve switching amount calculation section, 26; winch control valve control signal output section, 19a; telescopic control valve control signal, 19b; winch control valve control signal, a: telescopic operation signal, La: boom length detection signal, Sa ; Feed length detection signal,

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Hideyuki Sasaki             153 Yashimanakamachi, Takamatsu City, Kagawa Prefecture F term (reference) 3F205 AA01 CB08 CB16

Claims (1)

Claims: 1. A swivel post pivotally mounted on a base, a telescopic boom mounted on the pivot post so as to be able to undulate, and the telescopic boom driven by control oil from a telescopic control valve. First and second telescopic cylinders for sequentially expanding and contracting, a winch device attached to the turning post or the base end of the telescopic boom driven up and down by a winch motor driven by control oil from a winch control valve, and A hook suspended from the distal end of the telescopic boom so that the telescopic boom can be lifted and lowered by a wire rope drawn out from the winch device. A crane hook suspension length holding device that is configured to be different between the telescopic operation area by the cylinder and the telescopic operation area by the second telescopic cylinder Telescopic operation means for outputting a telescopic operation signal for instructing a valve switching direction and a valve switching amount of the telescopic control valve, a boom length for detecting an actual boom length of the telescopic boom and outputting a boom length detection signal Detecting means, wire feeding length detecting means for detecting the actual feeding length of the wire rope and outputting a feeding length detection signal, and expansion / contraction operation signals, boom length detection signals and feeding length detection from each of these means A controller for receiving a signal and outputting a control signal for switching control of the telescopic control valve and the winch control valve, the controller comprising: (1) operating the telescopic control valve in accordance with the telescopic operation signal based on the telescopic operation signal; An expansion / contraction control valve control signal for switching to the valve switching direction and the valve switching amount indicated by the signal is generated, and the expansion / contraction control valve control signal is output to the expansion / contraction control valve. (2) Based on the telescopic operation signal, the boom length detection signal and the payout length detection signal, the fluctuation amount of the boom length detection signal and the fluctuation amount of the actual wire payout length after receiving the telescopic operation signal A winch control valve control signal for switching the winch control valve to the valve switching direction and the valve switching amount is determined by obtaining a valve switching direction and a valve switching amount necessary for matching the winch control valve. The control valve control signal is output to the winch control valve. A hook hanging length holding device for a crane, wherein the device is configured as described above.