JPS6117366Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to a device for measuring the swing angle of a load suspended by a crane. In order to quickly attenuate the swing of a crane suspended load and improve cargo handling efficiency, it is being considered to control the acceleration/deceleration speed of the trolley based on the magnitude of the swing of the hoisted load. This is necessary. A conventional device for measuring the swing angle of a suspended load is shown in FIG. This is the load L hanging on trolley 1.
A detection rod 3 is provided which can swing together with the rope 2 on which the rope 2 is suspended, and the deflection angle is measured by detecting the deflection displacement of the detection rod 3 with a displacement meter 4.
However, with this device, 1) the detection rod 3 cannot be made long, resulting in small deflection and poor accuracy; and 2) minute vibrations occur in the contact area between the rope 2 and the detection rod 3, causing noise in the detection signal. There are problems such as poor accuracy. In addition, in the device shown in FIG. 2, a mark 5 is placed on the suspended load L, and the deflection angle is measured by detecting the mark 5 with an optical position detector 6 provided on the trolley 1. . However, this device has 1) non-contact measurements, so there is no noise due to contact, but the device is expensive. 2) Since it is an optical type, it is easily affected by surrounding brightness, and there are cases where it cannot be detected.
3) Since an optical precision instrument is provided on the trolley 1, there are problems such as a short life span of the device due to vibration. This idea was devised in view of the above-mentioned circumstances, and its purpose was to provide a hydraulic damper to dampen the swing of a load suspended from two ropes suspended centrally in a V-shape from a trolley. It is an object of the present invention to provide a swing angle measuring device for a crane suspended load that can accurately and reliably measure the swing angle of the suspended load in a crane. The case where one embodiment of this invention is applied to the container crane shown in FIG. 3 will be described below.
The crane body 7 is provided with a boom 8 extending toward the sea, and a trolley 1 is moved along this boom 8, and a container C is moved by two ropes A and B suspended from the center in a V-shape from the trolley 1. The main body 7 can also be moved along the quay 9, and the motors for moving and hoisting are connected to the boom 8. It is provided in the machine room 10 on the land side. This crane is provided with a hanging load steadying device as shown in FIGS. 4, 5, and 6, respectively. What is shown in FIG. 4 is a pulley connected to the piston rods of two oil field dampers 12 and 13 provided at the tip of a boom 8 with two ropes A and B being paid out from a winding drum 11 in a machine room 10. 15 and 16, and hung from a pair of rope pulleys 17 and 18 provided apart from each other on the trolley 1, and then suspended from the center in a V-shape, and wound around the lifting pulleys 19 and 20 of the container C. The final end is fixed to the land side end of the boom 8 by rotating it. And the above hydraulic damper 1
The cylinders 2 and 13 are connected to each other by hydraulic pipes 14 and 14 having damping valves 14a. Therefore, when the container C swings, the pistons of the hydraulic dampers 12 and 13 are displaced in proportion to the swing, and the dampers 12 and 13 move in proportion to the swing.
Since a resistance proportional to the swing speed is applied to the container C, swinging of the container C can be stopped by appropriately adjusting the damping valve 14a. Also, what is shown in Figure 5 is
A pulley connection body 26 having a pair of pulleys 24 and 25 is provided within the trolley 1 so as to be horizontally movable, and a hydraulic damper 27 having a damping valve 27a is fixed to the trolley 1, and the piston rod of this damper 27 is connected to the pulley connection body. 26, and the method of hanging ropes A and B is almost the same as that shown in FIG. In this case, since the pulley coupling body 26 is displaced in proportion to the swing of the container C, the swing of the container C is stopped by adjusting the damping valve 27a as in the case of FIG. Furthermore, in the one shown in FIG. 6, a fulcrum 28 is fixedly installed on the trolley 1, and a tilting body 29 is provided so as to be tiltable by supporting the central part on the fulcrum of the fulcrum 28. A pair of rope pulleys 17 and 18 are provided at the trolley 1, and both ends of the tilting body 29 are connected to piston rods of hydraulic dampers 30 and 31 fixed to the trolley 1. Corresponding cylinders of both hydraulic dampers 30, 31 are connected by hydraulic arrangements 32, 33 having damping valves 32a, 32a, respectively. Further, ropes A and B are hung in substantially the same manner as shown in FIG. In this case as well, since the tilting body 29 tilts in proportion to the swing of the container C, the swing of the container C is stopped by adjusting the damping valves 32a, 32a as in the case of FIG. By the way, when the above three types of steady restraint devices shown in FIGS. 4 to 6 are modeled, the result is shown in FIG. 7. Here, d: Trolley position m: Container mass x: Container horizontal position y: Container vertical position l ₁ : Left rope hanging length l ₂ : Right rope hanging length ₁ : Left rope hanging angle ₂ : Right rope hanging angle c: Cable Interval between hanging pulleys x _P : Damper piston displacement T ₁ : Left rope tension T ₂ : Right rope tension α: Rope elasticity ζ: Damper damping coefficient m _P : Damper piston mass g: Gravitational acceleration l ₀ : Rope length when unloaded Then, the force balance equation of the model is as follows. my=mg−T ₁ cos ₁ −T ₂ cos ₂ (1) mx=−T ₁ sin ₁ +T ₂ sin ₂ (2) l ₁ =l ₀ −xp+1/αT ₁ (3) l ₂ =l ₀ +xp+1/ αT ₂ (4) mxp=-ζxp+T ₂ -T ₁ (5) x=d+l ₁ sinφ ₁ (6) Then, if there is no swing of the container, l ₂ = l ₁ = l, and ₁ = +Δ・₂ =- If ΔT is approximated under the condition that the deflection angle Δ is small and the variation ΔT in the rope tension is found, ΔT ₁ =α(cl/2yΔ+xp) (7) ΔT ₂ =−α(cl/2yΔ+xp (8) , from equation (7), the deflection angle Δ is Δ=(ΔT ₁ /α−xp)2y/cl (9). Here, from equations (1) to (6) above, we can approximate and calculate ( 7) and (8) will be explained with reference to Fig. 11. From the similarity of triangles, <= ₂ ∴Ccos ₂ = l ₁ sin ( ₁ + ₂ ) l ₁ = cos ₂ /sin ( ₁ + ₂ )C(〓1
) Similarly, l ₂ = cos ₁ / sin ( ₁ + ₂ ) (〓2) (〓1), (〓2) can be substituted into equations (3) and 4 and rearranged to obtain T ₁ = α(l ₁ − l ₀ +xp) = α[coscos△+sinsin△/si
n2C-l ₀ +xp〕 (〓3) However, ₁ = +△ ₂ = -△. Here, the deflection angle △ is small and △≒0.
Considering that sin△=△ cos△=1, T ₁ = α [Ccos/sin2-l ₀ ] + αCsin
/sin2△+αxp (〓4) Similarly, T ₂ =α[Ccos/sin2-l ₀ ]-αCsin
/sin2△−αxp (〓5). Here, if the stationary terms (first term) are T ₁₀ and T ₂₀ , then T ₁₀ = T ₂₀ = α [Ccos/sin2-l ₀ ] (〓
6) Or, if the fluctuation terms are △T ₁ and △T ₂ , △T ₁ = αCsin/sin2△+αxp (〓7
) △T ₂ =-αCsin/sin2△-αxp(〓
8) Here, from the figure, cos = y/l, ∴△T ₁ = αCsin/2sin cos△+αxp = αCl/2y△+αxp = α(Cl/2y△
+xp (〓9)…(7) Similarly, △T ₂ =-αCl/2y△-αxp=-α(Cl/2
y△+xp) (〓10)...(8) is obtained. Therefore, the rope tension fluctuation on the right side of equation (9) above △
Measurements of T ₁ , damper piston displacement xp, rigging pulley interval c, and rope suspension length l are provided, and by setting the rope elasticity α and calculating the above equation (9) using a calculator, the suspended load can be calculated. Deflection angle △ can be measured. The rope tension T measuring device 35 may be, for example, a load cell and attached to the cylinder of a hydraulic damper as shown in Figure 8a, (b) a dedicated sheave may be installed in the middle of the rope, or (c) a load cell may be attached to the cylinder of the hydraulic damper as shown in Figure 8a. Attach it to the sheave for changing direction, or attach it to the end of the rope as shown in (d) and measure the rope tension T. The variation in tension △T ₁ is △T ₁ = T ₁ − T ₁₀
(T ₁₀ : Tension at rest) or T ₁ + T ₂ =
T ₁₀ + T ₂₀ (T ₂₀ : Tension at rest, T ₁₀ = T ₂₀
Since there is a relationship as follows, it can be determined from ΔT ₁ =T ₁ -T ₁ +T ₂ /2 =T ₁ -T ₂ /2. The piston displacement xp measuring device 36 uses, for example, a differential transformer or an inductor sin, and the movable side of the measuring device 36 is connected to the piston rod of the damper as shown in FIG. 7 to measure the displacement. Cable pulley interval c
As the measuring device, a measuring device that utilizes the rotational speed of a ball screw, which is generally used for adjusting the interval between the hanging pulleys 17 and 18, is used. A tachometer is installed on the winding drum 11 as a measuring device for the rope suspension length l, and the rope suspension length l is measured by multiplying the number of rotations by the drum diameter. Next, the rope elasticity α is α=AE/L (A: rope cross-sectional area, E: rope Young's modulus,
The Young's modulus E of the rope increases as the number of times it is used increases, and the rope length L, which affects the elasticity, is determined by the friction in each pulley (L: Rope length that affects elasticity). (in comparison to the actual length), these conditions should be taken into account when setting. In addition, the vertical position y of the container is

It is obtained by calculation from [Formula]. The deflection angle calculator 37 receives the outputs and set values of each of the measuring instruments as input and calculates the equation (9) above. Then, this deflection angle calculator 37 has a first
As shown in Figure 0, rope tension T, piston displacement
By inputting the measured values of xp, the distance between rope pulleys c, and the rope hanging vertical l, and giving the rope elasticity α as a set value, and calculating the above equation (9), the swing angle of the suspended load can be △ can be measured. Since the device for measuring the swing angle of a crane suspended load of this invention is as described above, it is possible to measure the swing angle of a suspended load more accurately than before and reliably without being affected by surrounding brightness, etc. Can be done.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of conventional swing angle measuring devices for different hanging loads, and FIG. 3 is a schematic explanatory diagram of a container crane to which the device of this invention is applied.
Figures 4 to 7 are explanatory diagrams and modeled explanatory diagrams of different hanging load stabilization devices used in the container crane in Figure 3, Figures 8 a, b,
c and d are explanatory diagrams of the installed state of the rope tension measuring device used in one embodiment of this invention, FIG. 9 is an explanatory diagram of the installed state of the piston displacement measuring device, and FIG.
This figure is also an explanatory diagram of the deflection angle calculator, and FIG. 11 is an explanatory diagram when performing approximate calculation. 1... Trolley, 11... Winding drum, 17,
18... Cable pulley, 12, 13, 27, 30,
31... Hydraulic damper, 35... Rope tension measuring device, 36... Piston change measuring device, 37... Deflection angle calculator.

Claims (1)

[Claim for Utility Model Registration] A pair of separated rope pulleys are provided to suspend two ropes fed out from a winding drum from a trolley in a V-shape at the center, and a hydraulic damper is provided to damp the swing of the suspended load. The above-mentioned crane is equipped with measuring instruments for the piston displacement xp of the hydraulic damper, rope tension T, spacing c of the rigging pulley, and rope suspension length l, and the outputs of these measuring instruments are input, and the rope elasticity α is
A swing angle measuring device for a crane suspended load, which is provided with a swing angle calculator that sets the swing angle Δ of the suspended load and calculates the swing angle Δ of the suspended load using the formula Δ=(ΔT ₁ /α ₋ x P )2y/cl.