JPS59143895A - Holder for height of hung load of derrick crane - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lifting crane that performs lifting work using a hoisting boom. This invention relates to a height holding device.

When moving a suspended load from one point to another during crane work using an undulating V-n, there are times when it is desired to maintain the suspended load at a constant height regardless of the boom angle. In such cases, the hoisting winch was operated manually at the same time as the boom was raised and lowered, and the operator visually maintained the suspended load at a constant height.

However, with this method, it is necessary to rely on the driver's intuition to determine whether or not the suspended load is maintained at a certain height, especially when the suspended load is located at a high place or other location that is difficult for the driver to see. It will be a difficult task. In such cases, it may be possible to carry out the work based on signals from the guide, but this is less safe and time-consuming as the crane operator does not have to directly check the condition of the suspended load. It takes a lot.

The present invention has been made in view of the above-mentioned circumstances, and is an undulation system that allows a suspended load to be easily and safely moved in a short time regardless of the zoom angle and while being held at a constant height. The purpose of the present invention is to provide a device for maintaining the suspended load height of a crane.

In order to achieve this object, the device of the present invention is used in a hoisting crane that performs lifting work using a hoisting boom. The travel length detector calculates the reference boom height at any boom angle and hoisting rope travel length from the initial value detected by the boom angle meter, and when the boom angle is changed from this reference state, The boom height after the change is calculated from the value detected by the boom angle meter, and the change in the height of the lifted load is calculated based on the calculated height values of both booms, and the change in the height of the lifted load is calculated. The hoisting winch of the hoisting rope is operated until the calculation result matches the moving length of the hoisting rope detected by the rope moving length detector. The system is equipped with an arithmetic and control device that operates the boom so that the height of the suspended load is automatically maintained constant following the ups and downs of the boom.

The present invention will be described in detail below with reference to FIGS. 1 to 6. Fig. 1 is a side view schematically showing an example of a luffing crane to which the device of the present invention is applied, Fig. 2 is an enlarged view of the upper part of the crane's boom and the outside of the hook, and Fig. 3 is an enlarged view of the crane's boom and its 4 is an enlarged cross-sectional view taken along the line IV--IV in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line ■-V in FIG. 4.

In each of these figures, 1 is the main body of the luffing crane, 2 is the boom, 3 and 41 are sheaves attached to the upper part of the boom 2, and 5 is the winding 10-no. One end of the hoisting rope 5 is connected to the hoisting winch 6 so that the hoisting rope 5 is wound up and unwound by the hoisting winch 6 provided on the crane main body 1, and the other end is connected to the sheave 3.4 and the hoisting rope 5. It is connected to the upper part of the boom 2 via a sheave 8 on the hook 7 side. Normally, one sheave 3 is provided for one hoisting rope 5, and the sheave 4 and sheave 8 each have the same number of soap bodies. The sheave is guided to the 4 side, and the hook is turned between the sheave 4 and the sheave 8 a number of times according to the number of sheath bodies.

Reference numeral 9 indicates a suspended load suspended from the hook 7, and 0 indicates an arithmetic and control unit provided in the operator's cab of the crane main body 9.

A game angle meter 11 detects the angle θ of the boom 2, and is provided on the mounting plate 2a at the bottom of the boom 2.

Reference numeral 12 denotes an axle that supports the sheave 4 in rotation. 13 is a permanent magnet, which is attached to the sheet body 4 of the sheave 4.
For example, m pieces are embedded and fixed at equal intervals on the outer periphery of the main body 4a, each with a part of the surface exposed. Further, a non-contact type switch 14 is disposed near the outer periphery of the sheath body 4a and constitutes a rope travel length detector which, together with the permanent magnet 13, detects the amount of rotation of the sheath body 4a, in other words, the travel length of the hoisting rope 5. It is set up. This switch 14 detects the magnetism of the permanent magnet 13 when it passes nearby, and thereby outputs a signal corresponding to the amount of rotation (rope movement length) of the sheave body 4a.

Here, based on FIG. 3, the winding 9 and unwinding when maintaining the suspended load height constant with the apparatus of the present invention will be explained. Here, we will discuss the case where the boom 2 moves between the position shown by the solid line and the position shown by the two-dot chain line in the figure.
In this case, it can be said that if the hoisting rope 5 is unwound (unwound) by an amount corresponding to ΔH in FIG. 7, the suspended load 9 can be moved while maintaining the same height.

Now, the distance from the stock bin 2b, which connects the boom 2 to the hoisting crane body 1 in a freely hoisting manner, to the axle 12 is L.
Assuming that B is ΔH, ΔH can be obtained as shown in the following equation.

Ho ”” L B sinθo “mouth”…
(1) 1(='L B output θ...
...(2) The condition for keeping the suspended load 9 at the same height before and after movement is Ho +Hc"=H+Hc+ΔH...
(3) Therefore, ΔH=Ho−I(=LB(sin θ(1'sln θ)=
LB×ΔS... River... (4) (However, ΔS=, 4θ6 sInθ) The winding (unwinding) length L of hoisting 0-f5 corresponding to the determined ΔH is the sheep of hoisting rope 5 If the number of multipliers between 4 and 8 is n, it can be calculated as shown in the following equation.

, O = LB x Δ5

Therefore, from the above equation (5), Δs(,4θo sin
It can be said that it is sufficient to wind up (feed out) the winding rotor 5 by a length proportional to θ). Also, t, in other words, ΔS
If is + (increase), wind up the loaf 05, - (
In the case of a decrease, it is sufficient to let out the hoisting rope 5.

Next, when the hoisting row f5 is wound up (unwound) by an amount corresponding to ΔS, this must be detected and the hoisting winch 6 (see Figure 1) must be stopped at that point. This will be explained below with reference to Figs. 4 and 5.The sheep body 4a of the sheep 4 is the first thing that is hung when the hoisting rotor 5 is hung from the sheep 3 to the sheep 4, and here, A permanent magnet 13 embedded in the outer periphery of the sheath main body 4a and a non-contact switch 14 arranged close to the outer periphery of the sheath main body 4a detect the passing length t' of the hoisting loaf 50 in the sheath main body 4a, and the hoisting winch 6 In other words, the passage length t' of the hoisting rotor 5 in the sheath main body 4a is
The number of pulses obtained by the permanent magnet 13 and the non-contact switch 14 is P, and the hoisting rope 5 passing through the sheath body 4a
Assuming that the pitch circle of is D and the number of permanent magnets 13 is m as described above, it is determined by the following equation.

t' = -x p == K/ X P ...Mountain... (
6) Here, since π, D and m are constant 1-direct,'
is also a constant value.

From the above equation (6), it can be concluded that the passage length t' of the rolled up loaf "5" in the 5-series main body 4a is proportional to the 7Russ number P.

If the passing length t' of the hoisting loaf 05 in the sheep body 4a is equal to the absolute value IAI of t, it can be said that the suspended load 9 has moved at the same height.

Here, Δt=lzl-t' (7)
Then, in the case of ΔtNO, the winding low f5 is changed to the winding 9 (
In addition, if Δ1=00, the hoisting rope 5 has to be
It is not necessary to wind up (unwind) (0) Figure 6 is a diagram showing the circuit of the device of the present invention that winds up, unwinds, and automatically stops the winding and unwinding. The suspended load height control by the device will be explained.Now, let us assume that the boom 2, in other words, the suspended load 9, is at a predetermined height, and before raising or lowering the boom 2, turn on the start switch 21 and start the zoom at that time. The value θ of the boom angle meter 11 according to the height is sent to the initial value holding circuit n to the initial value θ0.
, and hold it as a constant value during the work. In this case, θ0 is sinθ0 in the transfer function circuit. It is also assumed that power is supplied to each circuit section by turning on the start switch 21.

First, as described above, the initial value θ0 is stored in the initial value holding circuit 22.
is given, and after this is set to the ratio θ0 by the transfer function circuit 5in23, when the boom 2 is raised and lowered, the boom angle meter 11
The value θ changes. This value θ is the transfer function circuit sin
24 is the ground θ, and this and the transfer function circuit sln 23
From the initial value sinθ0 from and 25 to the transfer function circuit,
The required length t of the winding (unwinding) of the hoisting rope 5 is determined as determined using equations (1) to (5) above. This l
1it is converted to ltl by the absolute value conversion circuit 26.

On the other hand, a permanent magnet 13 embedded in the outer periphery of the sheath main body 4a
The number of pulses P corresponding to the amount of rotation of the sheath body 4a is detected by the non-contact switch 14, and the number of pulses P corresponding to the rotation amount of the sheath body 4a is determined by the transfer function circuit as determined by the above equation (6). Find the passage length t'.

The electromagnetic directional control valve 31 is operated when the difference Δt-JtJ-t' (see equation (7) above) between this t' and the above-mentioned 1t1 is Δt'-zo. Here, the electromagnetic directional control valve 31 is connected in parallel with a manual directional valve 32 that is operated during normal operation except when the suspended load height is held constant. Assuming that Δ1>0 is determined by the discrimination circuit, the electromagnetic directional control valve 31 activates the hydraulic motor 33 in the direction in which the sonoid 31a is excited and the hoisting row f5 is wound up, and rotates the hoisting winch 6. . Conversely, when it is determined that Δ1<0, the electromagnetic directional control valve 31ft solenoid 31b is energized and the hydraulic motor 33 is operated in the direction in which the hoisting loaf 05 is fed out, and the hoisting winch 6 is activated.
Rotate.

Here, the hydraulic motor 33 is a hydraulic pump 34 and an oil tank 35.
It is operated by pressure oil that is sucked in and fed under pressure from the electromagnetic directional control valve 31 or the manual directional control valve 3.
It is determined by the operation in step 2. During operation with the suspended load height held constant, the human-powered directional control valve 32 is kept in the upright position shown in the figure, and the electromagnetic directional control valve 31 is activated or stopped depending on the judgment result of the discrimination circuit. °pThe hydraulic motor 33 is activated or deactivated. During normal operation, the start switch 21 is in the OF"F L position, and the electromagnetic directional control valve 31 maintains a neutral position because no command signal is input. Therefore, the hydraulic motor 33 is activated by operating the human-powered directional control valve 32. Activate or deactivate.

In addition, in the above-mentioned embodiment, the rope travel length detector was configured with the permanent magnet 13 and the non-contact switch 15, but it is not limited to this, and may be configured using a rotary encoder, a photoelectronic switch, etc. In the above embodiment, the ON-OFF switching type electromagnetic 1till H valve 31 is used as the direction control valve operated on the discrimination circuit side, but the amount of pressure oil sent to the hydraulic motor 33 is proportional to the value of Δt. A servo valve may also be used, which provides faster and more precise control.

As described above, the present invention provides a hoisting crane that performs hoisting work using a hoisting boom, which includes a game angle meter that detects the angle of the boom, and a rope mover that detects the moving length of the hoisting loaf of the hoisted load. The length detector calculates the reference boom height feeling at any boom angle and hoisting loaf travel length from the initial value detected by the boom angle meter, and when the boom angle is changed from this reference state, υCalculate the post-change boom height feeling from the value detected by the boom angle meter, calculate the amount of change in the height of the suspended load based on the calculated height values of both booms, and calculate the amount of change in the height of the suspended load. The hoisting winch of the hoisting loaf is operated until the calculation result matches the moving length of the hoisting loaf detected by the rope moving length detector. The height of the suspended load is automatically maintained at a constant level regardless of the boom angle, and is maintained at a constant height regardless of the boom angle. This has the effect of allowing suspended loads to be moved easily, safely, and in a short period of time.

Furthermore, since the boom angle meter is legally required to be installed on the crane, there is no need to newly install it, which is economical. Furthermore, when detecting a change in boom angle, the boom angle before hoisting the boom is used as a reference, so there is an effect that the height of the suspended load can be maintained constant even when the hoisting crane body is on an inclined surface.

[Brief explanation of the drawing]

Fig. 1 is a side view schematically showing an example of a luffing crane to which the device of the present invention is applied, Fig. 2 is an enlarged view of the upper part of the boom and hook portion of the crane, and Fig. 3 is the boom of the crane and its surroundings. 4 is an enlarged cross-sectional view taken along the line IV-IV in FIG. 3, and FIG. 5 is a side view showing the details of
FIG. 6, a sectional view taken along the V line, is a diagram showing an example of the circuit of the device of the present invention. 1... Lifting crane body, 2... Boom, 3,4°8... Seed, 5... Hoisting loaf, 6... Hoisting winch, 7... Hook, 9... Hanging load, ] 0... Arithmetic control unit #, 11... Boom angle meter, 13... Permanent magnet, 14... Non-contact switch. Patent applicant Hitachi Construction Machinery Co., Ltd. Agent Patent attorney Masami Akimoto 93 Figure

Claims (1)

[Claims] A hoisting crane that performs lifting work using a hoisting boom is equipped with a boom angle meter that detects the angle of the boom, a rope travel length detector that detects the moving length of the hoisting rope for hoisting, and a boom angle and hoisting device that detects the lifting rope. When the reference boom height at the travel length of the upper rope is calculated from the initial value detected by the boom angle meter, and the boom angle is changed from this reference state, the game height after the change is calculated as described above. Calculate from the value detected by the boom angle meter, calculate the amount of change in the height of the suspended load from these two boom height calculation values, and calculate the travel length of the hoisting rope to make this change in the height of the suspended load zero. and a calculation sterilization device that operates the hoisting winch of the hoisting nozzle until the calculation result matches the travel length of the hoisting nozzle detected by the rope travel length detector, and A suspended load height holding device for a undulating crane that automatically maintains the height of a suspended load at a constant level following undulations.