JPS62205993A - Position detector for hook of 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 [Field of Industrial Application] The present invention relates to a crane hook position detection device that corrects detection errors caused by elongation of a hanging load wire.

[Conventional technology]

In conventional devices of this kind, the length of the wire for lifting a load from the state where the hook is at the home position is determined from the rotation of the top sheave or winch, and this length of wire is divided by the number of times the wire is hooked. The position of the hook from the tip of the boom is detected.

Note that the position of the hook is essential when displaying the height of the hook above the ground, or when controlling to maintain a constant height above the ground for shipping regardless of the boom angle.

[Problems to be Solved by the Invention] In cranes, twisted wires are used as shipping wires in consideration of durability, safety, ease of use, etc., and as a result, loads are not applied to the wires for lifting loads. The elongation of the wire when acted upon is considerable.

However, in the above-mentioned conventional hook position extraction method, the elongation of the shipping wire is not taken into consideration, which causes an error in the detected hook position, and furthermore, this error causes a large amount of load acting on the wire. There was an inconvenience that it varied depending on the weather.

[Means for solving problems]

The present invention provides a payout length detecting means for detecting a payout length of a shipping wire from a state where a hook is at an origin position, a tension detecting means for detecting a tension of the wire, the payout length, the tension, and the means for determining the amount of elongation of the wire based on the length of the wire from the detection position of the payout length to the tip of the boom; and a means for determining the position of the hook.

[Effect]

According to the present invention, a hook position detection error caused by elongation of the wire is corrected.

[Real 7+! i example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of a hook position detection device according to the present invention, and FIG. 2 shows an example of a crane to which this embodiment is applied.

In this embodiment, a tension detector 1 is provided on the basic boom 21a of the boom 21 in order to detect the tension applied by the hanging load wire.

This tension detector 10 has an arm 10 as shown in FIG.
The arm 101 has a movable sheave 102 supported on the arm 101, two fixed sheaves 103 and 104, and a load cell 105 that detects the force acting on the arm 101.

In this tension detector, the movable sheave 102 is provided so that the wire force is deviated upward. Therefore, when tension is applied to the wire, the load cell 105 is pressed by the arm 101, so that the load cell 105 outputs a signal corresponding to the tension applied to the wire. The output of this load cell 105 is then applied to the CPU 4 via the amplifier 2 and the A10 converter 3 as shown in FIG.

The incremental encoder 5 shown in FIG. 1 is connected to the rotating shaft of the top sheave n, as shown in FIG. 5. Therefore, the encoder 5 outputs A-phase pulse signals and B-phase pulse signals corresponding to the number of rotations in the forward rotation direction $1 and the amount of rotation in the pre-rotation direction of the top sheave n, and these signals are sent to the direction determining circuit. 6 is input.

The A-phase pulse signal and the B-phase pulse signal have a phase of 9 to each other.
Based on this phase difference, when the A-phase pulse No. 1g is input, the direction discrimination circuit 6 which has a 0° difference applies this signal to the up-count input terminal of the up-down counter 7, and determines whether the B-phase pulse signal is When input, this signal is added to the down count input terminal of the Callan/97.

The limit switch 8 for preventing overwinding outputs a home signal when the hook iron rises to the home position shown in FIG. is input.

Note that the output signal of the limit switch 8 is also used as a signal for restraining the hoisting operation of the load winch.

Next, the number of wires to be multiplied will be explained. Figure 5 shows a state where hook Z is suspended by two wires, with a number of hooks of 2, and Figure 6 shows a state where hook Z3 is suspended with four wires, which is a number of hooks of 4.
The status of each is shown. In this way, the number of hooks means the number of wires suspended from the hook device, and the sheave group 5 located below the top mark is used when changing the number of hooks.

The multiplier setter 9 shown in FIG. 1 instructs the CPU 4 to set the multiplier, and is composed of a changeover switch.

Assuming that the hook device is now at the home position as shown in FIG. 4, the counter 7 is reset by the output of the limit switch 17 in this state. Here, when the wire is moved by the winch in the direction in which the wire is fed out, the encoder 5 outputs a pulse signal corresponding to the movement 4 (b), and this signal is counted up by the counter 7. If Sae is reversed, counter 7
The output pulses of the encoder 5 are counted down.

As a result, the count of the counter 7 indicates the length l of the silver wire fed out from the state where the hook n was at the origin position. Then, the multiplier set by the multiplier setter 9 is n.
Then, the position (distance) D of the hook A from the tip of the boom 21 is D −= '/n ・・・・・・・・・・・・・・・
・It is expressed as (1).

By the way, if the silver wire does not stretch, the position of the hook can be determined accurately based on the above formula (1), but if the wire stretches due to a load acting on the hook, the detection will be difficult. This will cause an error in the hook position.

The above wire elongation occurs not only in the part from sheave n to the wire end on the boom tip 11W side (also in the part from the winch to sheave 4. However, in the above embodiment, the wire elongation occurs at the boom tip position). Since the wire length is detected, the elongation of the wire between the winch 24 and the boom tip is included in the count of the counter 7.

In short, the parts where the elongation of the wire must be considered are the first wire part interposed between the payout length detection position and the tip of the boom (in the above example, the length of this part is zero) and the tip of the boom. and the second wire part interposed between the wire end on the boom tip side (the length of this part is the unrolling length l), and the above should be taken into account when the length of the wire part of box 2 is L. To explain how to determine the elongation of the silver wire, the elastic modulus of the entire 1% second wire section is: K=N/I, +z ・・・・・・・・・・・・・・・・・・
(2) However, k is a constant determined by the material of the wire, etc. Then, from Hooke's law, T=k・(△L+Δ))・・・・・・・・・・・・(3
) However, since the following relationship holds true: T; wire tension ΔL; tension Amount of elongation of the first wire portion based on tension; l; elongation amount of the second wire portion based on tension. The sum of the respective elongation amounts of the second wire portion is given by the following equation (4).

ΔL+Δz=T7K ・・・・・・・・・・・・(4)
Therefore, the feeding length l measured by the counter 7 is (
4) Adding the amount of elongation shown in the formula is the true payout length 1T = l + ΔL + Δg considering the elongation of the silver wire. Therefore, the true hook position considering the elongation of the silver wire is according to equation (1). It is given by the following equation (5).

DT=lT/. =gi+ΔL+Δ'/n'...(5
) FIG. 7 shows the processing procedure of the CPU 4.

As shown in the figure, in the CPU 4, the length L of the first wire portion detected by means to be described later, the payout length L (length of the “th” wire portion) detected by the counter 7,
The tension T detected by the tension detector, the wire multiplication number n indicated by the multiplication number setting device 9, and the constant k shown in equation (2) stored in a memory (not shown) are input (step 61). ).

Then, the calculations shown in equations (2), (4), and (5) are sequentially executed (steps 62 to 64), and then the hook digit 1fDT obtained in step 64 is displayed as shown in FIG. Processing for displaying on the device 10 is executed (step 65).

In the above embodiment, since the detection position of the wire payout length l is performed at the tip of the boom 21, the length of the first wire portion shown in equation (2), that is, the detection position of the payout length l and the boom tip The length of the wire interposed between them is zero. Naturally, ΔL shown in equations (3) and (4) also becomes zero.

In the above embodiment, the payout length j of the silver wire is determined based on the amount of rotation of the top sheave n, and this payout length l is determined by the rotation of the winch U ftrIcJI.

It is also possible to detect the In this case, the encoder 5 is attached to the winch.

When determining the payout length from the amount of rotation of the winch, the first wire portion exists, and this portion is a section from each winch to sheave n. The length of this first wire section is then equal to the length of the boom 21.

The boom length detector 11 shown in FIG. 1 is provided to detect the length of the boom 21, and includes a drum for winding the wire lla and a potentiometer (not shown) for detecting the amount of rotation of this drum. It has a configuration with. Since the tip of the wire lla is hooked to the tip of the boom 21, the output of the potentiometer indicates the boom length.

In this embodiment, in step 61 in FIG. 7, the length L of the first wire portion is determined by the boom length detector 1.
1, and then step 6 as in the previous embodiment.
The calculations shown in 2 to 64 are executed to determine the position D of hook B.

Thus, even when determining the payout length l from the amount of rotation of the winch, the true hook position that takes into account the elongation of the wire bundle is required.

The present invention is also applicable to detecting the extension length l on the basic boom 21a of the boom 21, and in this case, the output of the boom length detector 11 and the detection position of the extension length j (the encoder 5) Installation location)
In the above embodiment, the tension acting on the wire is detected by the tension detector 1 shown in FIG. It is also possible.

That is, as shown in Fig. 8, the hanging load is W, the boom weight is WB, the boom length is LB, and the distance from the foot pin position of the boom to the center of gravity of the boom is LG%.The axis of the luffing cylinder d shown in Fig. 2 If the force is F1 and the boom angle is θ, then
The following relationship holds true.

However, X: Length of the perpendicular line drawn from the foot pin position to the axis of cylinder H. It is possible to calculate the tension T by detecting F, θ, X, and LB shown in equation (6).

Note that since the axial force F corresponds to the differential pressure between the head pressure and the bottom pressure of the cylinder n, it can be detected using an oil pressure sensor. Further, θ can be detected by providing an angle detector such as a potentiometer at the foot pin position, and since X is a variable with θ as a parameter, it can be obtained by detecting θ. And L can be detected by the boom length detector 11.

〔Effect of the invention〕

According to the present invention, even if the shipping wire is stretched due to a hanging load, the hook position can be detected once.

Brief Description of the Drawings Fig. 1 is a block diagram showing an embodiment of a hook position detection device according to the present invention, and Fig. 2 conceptually shows an example of a crane to which the present invention is applied. The side view and Fig. 3 are conceptual diagrams illustrating the configuration of the tension detector, Fig. 4 is a conceptual diagram showing the state in which the hook has reached the origin position, and Figs. 5 and 6 are diagrams showing the number of wire hooks, respectively. FIG. 7 is a flowchart showing an example of the processing procedure of the CPU shown in FIG. 1, and FIG. 8 is an explanatory diagram of another method of tension detection.

1... Tension detector, 4... CPU, 5... Incremental encoder, 6... Direction discrimination circuit, 7...
・Up/down counter, 8... Limit switch for overwinding prevention, 9... Multiplication number setting device, 11... Boom length detector, Machining... wire, 21... Boom, n...
Top sheave, otsu... hook, sae... winch.

−~) Applicant's agent Takahisa Kimura l 11 dried 1−=−−−−”−=”” Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 8

Claims (1)

[Scope of Claims] A length detecting means for detecting the length of the hanging load wire from the state where the hook is at the origin position, a tension detecting means for detecting the tension of the wire, the length of the wire, and the tension. and means for determining the amount of elongation of the wire based on the length of the wire from the detection position of the payout length to the tip of the boom; A hook position detection device for a crane, comprising means for determining the position of the hook with respect to the tip of the boom.