JPH021072B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cable speed detection device used when winding/feeding out a cable or the like with a winch or the like used in a ship.

[Conventional technology]

In the past, when attempting to display the cable speed of a winch or the like, it was usually detected by a device that touched the cable.

[Problem that the invention seeks to solve]

However, this has a complicated structure, and the part that touches the cable is likely to wear out, resulting in failure or inaccuracy.

[Means for solving problems]

The present invention detects the speed of the cable from a signal from a rotary encoder that detects the rotation of a drum that winds the cable.

The present invention comprises a rotary encoder 20 that detects the rotation of a winding drum 2 that winds a cable 7, and a calculator 23 that corrects a signal a from the rotary encoder 20 according to the number n of winding layers of the cable.

[Effect]

The rotary encoder 20 generates a signal a proportional to the rotational speed of the winding drum 2 on which the cable 7 is wound. Since the relationship between this output signal a and the cable speed changes depending on the number n of cable winding layers, this correction calculation is performed by the calculator 23 to detect the correct cable speed.

〔Example〕

Next, the cable speed detection operation will be explained with reference to FIG.

While the hydraulic winch 1 is in operation, the winding drum 2 rotates, and a rotary encoder 20 provided on its shaft 3 generates a pulse signal a proportional to the number of rotations of the winding drum 2.
is generated, the signal a is converted into a voltage signal _a1 proportional to the frequency by the F/V converter 21, the signal _a1 is converted into a digital signal a2 by the A/D converter 22, and the signal a is converted to a digital signal _a2 by the A/D converter 22. It is sent to the circuit or analog/digital computing unit 23, and a ₃ = a ₂・(D+n・E/D−1) If D is the winding diameter of the first layer of the winch, E: the winding thickness per layer. Value n: Number of winding layers (0, 1, 2,...n) Alternatively, D may be the winding diameter of the m-th layer of the winch. At this time, (m=0, 1, 2,...) E: Winding thickness value per layer n: Number of winding layers (-m, m+1,..., nm) Calculation, that is, winding layer correction, output signal a ₃
becomes an analog signal _a4 in the D/A converter 24, and this signal _a4 is added to the signal _a1 in the adder circuit 25 to become a signal _a5 proportional to the cable speed, which is amplified by the meter amplifier 26 and sent to the cable speed meter 27. This is what is displayed by.

The number of winding layers (formula n) is detected as follows.

Since the signal a from the rotary encoder 20 is a two-phase signal (90° phase difference), the discriminator 41 determines whether
It becomes the feeding signal d1. The calculator 23 increases (when d1 is a winding signal) or decrements (when d1 is a feeding signal) its internal counter (not shown) in accordance with the winding/feeding signal d1. Since the number of rows for each layer of the winding drum 2 is constant, the number of pulses generated by the rotary encoder 20 is also constant for each layer, so the number of winding layers n can be determined from the value of the internal counter.

The internal counter must be reset when the winding amount is known. For this purpose, reset button 4
2, and when the arithmetic unit 23 receives this signal f,
The internal counter is preset to a value corresponding to a known winding amount.

In the above device, if the arithmetic unit 23 fails, if it is disabled by a switch (not shown), its output signal _a4 becomes 0, so the voltage signal _a1 proportional to the number of rotations of the drum is sent directly to the adding circuit 2.
5. Displayed on cable speed meter 27 via meter amplifier 26.

If a failure of the arithmetic unit 23 is not assumed, the second
The configuration shown in the figure can be taken.

That is, in FIG. 2, the interface 101 is
The F/V converter 21, A/D converter 22,
It includes each function of the discriminator 41, and the arithmetic unit 2
3 calculates the following formula and swings the cable speed meter 27 through the D/A converter 24.

a ₆ =a·(D+n·E/D) Here, D, n, and E are the same as in the previous formula.

〔effect〕

As described above, according to the present invention, the speed of the cable is detected by the number of revolutions of the winding drum, so that the speed of the cable can be detected without the need for a device that directly touches the cable.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a cable speed detection circuit of a hydraulic winch according to an embodiment of the present invention, and FIG. 2 is a block diagram of a winding layer number detection circuit. 7... Cable, 2... Winding drum, 20...
Rotary encoder, a... Signal, n... Number of winding layers, 23... Arithmetic unit.

Claims (1)

[Claims] 1. A cable speed detection device for a hydraulic winch, etc., comprising a rotary encoder that detects the rotation of a winding drum that winds a cable, and a computing unit that corrects the signal of the rotary encoder according to the number of cable winding layers.