JPS6236445B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cable traction device for a cable hoist incorporating a lifting device.

Conventionally, communication or power cable hoisting machines have been used to lay cables on the seabed or to hoist them up from the seabed for repairs, and the laying and hoisting work is generally carried out in the following manner.

First, to explain the case of laying cables with reference to Figure 1, cable b exiting cable tank a
passes through a trough c that serves as a guide, a cable traction device d, winds the required number of turns in the circumferential direction of the cable hoist drum e, and a cable tension measuring device f.
Then, it is laid to the seabed via the bow sheave g or stern sheave. The laying work in this case is carried out by operating the cable hoist and cable traction device d.

When cable b is laid on the seabed for a required length, tension is applied to the cable due to its own weight. With this tension, the cable b wound around the drum e tends to slip on the surface of the drum e. In the figure, h is the installation direction and i is the pulling direction.

Therefore, in order to prevent this slippage, a back tension (pulling the cable wound around the drum) is applied by the cable pulling device d, so that the cable is brought into close contact with the circumference of the drum. That is, the cable traction device d
is rotated slightly slower than the rotational speed of drum e to generate back tension.

Next, when hoisting the cable from the seabed, cable b is hoisted from the seabed in the reverse order of the installation described above, but at this time, the rotational speed of cable traction device d is operated slightly faster than the drum to give tension to the cable. , preventing the cable from slipping on the drum surface.

One type of cable pulling device that generates tension to prevent the cable from slipping on the drum surface during laying or hoisting is the roller type (including V sheave type).
However, to explain the conventional structure of this type with reference to FIGS. 2 and 3, 1 is a cable, 2 is a driving roller, 3 is a presser roller, 4 is a driving hydraulic motor (or electric motor), 5, 6 is a bearing, 7 is an arm, 8 is a crimping actuator, 9 is a support stand, 10 is a unit stand, and 11 is a moving actuator.

Now, during laying and hoisting work, the cable 1 is held between the driving roller 2 and the holding roller 3.
In addition, the lower driving roller 2 is driven (rotated) in forward and reverse directions.
It is directly connected to a hydraulic motor (or electric motor) 4 and rotates (in forward and reverse directions). On the other hand, the pressing roller 3 presses the cable on the driving roller 2 via the arm 7 by the operation of the pressing actuator 8. Furthermore, since the holding roller 3 presses the cable, it rotates as the cable moves.

By the way, the back tension (tension) F produced by the cable pulling device is the pressing force W of the presser roller 3 that presses the cable, and the pressure force W of the pressing roller 3 that presses the cable,
If the coefficient of friction between the cable 1 and the cable 1 is μ, then F=
It is W・μ.

The power of the cable traction device is determined by multiplying this F by the cable speed V (m/min). The unit stand 10 can be moved along the ship's side by sliding on the hull stand using a moving actuator 11, and the cable can be set at any position on the drum. Further, the unit stand 10 is installed on the hull stand.

However, the conventional device has the following drawbacks. In other words, in the roller type, the contact pressure at the crimping part X between the roller and the cable has a nearly localized contact pressure distribution, and in order to obtain a large traction force, it is necessary to apply a large pressure force with the presser roller (μ (is a value determined between materials and is considered a constant), therefore, there was an excessive surface pressure, and this surface pressure could cause a failure in the cable.

The present invention has been proposed in order to solve the above-mentioned conventional drawbacks, and is to add a lifting device to the conventional cable traction device, and use this when the cable tension is high to raise the cable attachment point of the cable traction device. It is an object of the present invention to provide a cable traction device capable of obtaining a large tension of the cable traction device with a small crimping force by effectively utilizing the downward component of the cable's own tension.

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 4 and 5 show embodiments of the present invention,
1 is a cable, 2 is a drive roller, 3 is a presser roller, 4 is a hydraulic motor (or electric motor), 5 and 6 are bearings, 7 is an arm, 8 is a crimping actuator, 9 is a support stand, and 10 is a unit stand. , 11 are moving actuators, which are the same as those in the conventional device. Further, 12 is an actuator for lifting, 13 is a support for lifting, and 14 is a hull stand.

In the present invention, an elevating actuator 12 is added to the conventional structures 1 to 11, and a function of elevating the conventional unit upward and downward is added.
That is, actuators 12 are placed on both sides of the bottom of the unit.
It can be equipped and operated to raise and lower the entire unit as required.

The lifting actuator 12 may be driven by air or hydraulics, or manually in some cases, and the unit stand 10 supports the actuator 1 with the support stand 13 as a fulcrum.
2 moves up and down. Note that the actuator 12
In Figures 4 and 5, there are two sets on each side, but if necessary, they can be installed at the four corners and installed on one unit stand.
0 can also be made to be able to be raised and lowered entirely.

Next, to explain the operation, when the cable speed is high, the cable tension is often low, so the back tension of the cable traction device can be small, and the cable traction device can be moved using the conventional method that does not use a lifting device. It will be easier to pass the cable if you drive. That is, since the drum surface and the point of application of the cable pulling device are at approximately the same height level, the cable passes smoothly.

However, as the cable tension increases, the back tension of the cable traction device also needs to be large, and at this time, the lifting device (actuator 12) pushes up the unit base 10 (from point A to point A', and The attachment point of the cable is RO → RO′). Furthermore, when the point of force changes from RO to RO', the following effect is exhibited.

i.e. the back tension of the cable traction device.
F′ is as follows. In Fig. 6, W: Pressure force of presser roller 3 that presses the cable (Kg) μ: Coefficient of friction between drive roller 2 and cable (-) w: Downward portion of cable tension caused by the higher application point The force (Kg) is the back tension of the cable traction device.
F′ becomes F′=W・μ+wμ, which means wμ compared to the conventional
The back tension (tension) increases accordingly.

The present invention is constructed as described above in detail, and since the downward force due to the tension of the cable itself is used as part of the crimping force, the crimping force of the lifting actuator is reduced, and the crimping mechanism is Can be made small. In addition, the local surface pressure applied to the cable is reduced, and the adverse effects on the cable can be reduced.

When the cable traction device is further pushed up by the lifting device, the cable passing position of the cable traction device becomes higher than the cable entrance of the cable tank.
Therefore, after passing through the cable traction device during hoisting, the cable is in a state where it can easily move from a high position to a low position, and the cable bending that often occurs in the past (between the cable tank and the cable traction device) is reduced. , the progress of the cable is no longer obstructed, and the tension loss of the cable traction device is reduced.

[Brief explanation of the drawing]

Fig. 1 is a side view showing the state of arrangement inside a conventional cable laying ship, Fig. 2 is a side view showing an example of a conventional cable traction device, Fig. 3 is a view in the direction of arrow A in Fig. 2, The figures are a side view of a cable traction device showing an embodiment of the present invention, FIG. 5 is a view taken in the direction of arrow B in FIG.
The figure is an explanatory diagram showing the pressing force and the downward component force when the drive roller and presser roller are raised. Explanation of main parts of the diagram 1... Cable, 2... Drive roller, 3... Presser roller, 4... Hydraulic motor,
8... Actuator for crimping, 10... Unit stand,
12...Elevating actuator, 13...Elevating support base.

Claims (1)

[Claims] 1. In a cable traction device that installs and pulls up a cable by sandwiching the cable between a driving roller that rotates in forward and reverse directions and a holding roller that can be crimped onto the drive roller, at least one unit base on which the cable traction device is mounted is installed. A cable traction device characterized in that lifting actuators capable of lifting and lowering the unit base are connected to both corners.