JPH023923B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is aimed at investigating the linearity (planar shape and longitudinal shape) of a conduit for laying communication cables or power cables buried in the ground. The present invention relates to a length measuring device that measures the traveling length of a cable connected to a sensor in order to know the position of a sensor passing through the sensor, and particularly relates to a length measuring device suitable for measuring the length of a small diameter cable.

[Prior art and its drawbacks]

As shown in FIG. 6, a known cable length measuring device has a length measuring roller 2 facing the middle of two support rollers 1, 1, which rotates as the cable 3 advances. The cable length is measured by detecting the rotation speed of the cable. However, while this method is effective for measuring the length of a rigid cable with a large outer diameter, a cable with a small diameter and low rigidity will bend between the supporting rollers due to its own weight, as shown by the chain line, and come into contact with the measuring roller. It cannot be measured because it does not.

In addition, conventional length measuring instruments are often used simply to measure the length of cables within manufacturing plants.
Therefore, it was common to install it on the floor, and there was almost nothing to fix it to the pipe entrance.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a length measuring device that can be fixed to a pipe port and that can measure the length of a cable with high precision even with a small diameter cable.

〔composition〕

The length measuring device of this invention has a clamp mechanism that fixes the main body to the pipe opening by pressing a contact provided on the arm against the inner surface of the pipe, a pair of rollers facing each other with the cable at the center, and the rotation speed of one of the rollers. a cable length measuring mechanism consisting of a detector that detects and converts it into an electrical signal, a counter that integrates and displays the signal from the detector, or a calculation display that converts the integrated signal into a length and displays it, and the other of the above. A roller reversal prevention mechanism capable of releasing the check, comprising a pressing means for pressing the roller into contact with the cable, a ratchet wheel integrated with the one roller, and a check claw that is biased by the pressing body and locked to the ratchet wheel. It has a built-in configuration.

[Examples and effects]

Embodiments and operations of the present invention will be described below with reference to the attached FIGS. 1 to 5.

First, Figure 12 shows how the length measuring device is used. In this figure, 4 is a conduit for laying cables, 5 is a linear confirmation sensor that is pulled by a tow rope 6 and advances in the conduit, and 3 is a signal transmission cable for the sensor to be measured, and the length measuring device of the present invention Reference numeral 10 is fixed to the open end of the conduit (conduit entrance), and measures the length of the cable.

Now, as shown in FIG. 2, the length measuring device 10 of the embodiment has an arm 12 inserted into the conduit 4 in front of the main body 11, and a clamp for fixing the main body to the conduit opening on this arm. A mechanism 20 is provided.

The clamp mechanism 20 includes a cam-type movable contact 22 that rotates around a pivot shaft 21 supported by the arm, a fixed contact 23 provided on both sides of the lower part of the arm 12 as shown in FIG. It consists of a screw shaft 24 that is screwed into the screw shaft 24 and whose tip is in contact with the rotating tip of the movable contactor 22, and a torque wrench 25 that rotates this shaft.When the shaft 24 is moved forward by operating the wrench, the shaft is pushed The movable contact 22 rotates from the position shown by the chain line to the position shown by the solid line, and its arcuate edge contacts the inner surface of the conduit 4, and a force that pushes the main body downward acts. This force is then applied to the fixed contact 23.
The contacts 22 and 23 are received by the pipe and come into pressure contact with the inner surface of the pipe, and the main body is fixed to the pipe opening.

Note that a hydraulic clamp or a general screw clamp may be substituted for the movable contact 22, and it is also possible to make all the contacts movable, although this is not economically preferable.

Next, at the rear of the main body 11, there are provided a mechanism 30 for measuring the length of the cable that has passed, a pressing means 40 for pressing one of the length measuring rollers to the cable, and a mechanism 50 for preventing the length measuring roller from reversing. .

The length measuring mechanism 30 is operated by a pair of length measuring rollers 31 and 32 that are arranged opposite to each other with the cable 3 in between, and a protrusion 34 provided on the outer periphery of a cam roller 33 (see FIG. 4) that is integrated with the roller 32. The limit switch 35 is made up of a counter or an arithmetic display (not shown) connected to a signal cable of this switch, and the limit switch 35 is activated by the protrusion 34 of the cam roller for each revolution of the roller 32, which rotates as the cable advances. is turned "ON" and "OFF", and the electrical signal emitted at this time is integrated and displayed on a counter, or received and integrated on a calculation display,
In addition, the length of the cable is measured by converting it to length and displaying it. Here, the rotation speed of the roller 32 may be detected by using a proximity switch such as a magnetic sensor or an optical sensor in addition to a limit switch.

The pressing means 40 is provided to prevent the length measuring roller from slipping, and includes a spring 41 that urges the movable arm 36, which is pivotally supported by the main body and supports the roller 31, toward the cable side. It consists of a screw 42 that adjusts the pressing force of the spring, but instead of the spring 41, other known pressing means such as a cylinder can be used, and if a cylinder or the like that can adjust the pressing force is used, the adjusting screw 42 can be omitted. Ru.

On the other hand, as can be seen clearly in FIG. 4, the roller reversal prevention mechanism 50 includes a one-way ratchet wheel 51 integrated with the roller 32, rotatably supported by the main body, and pushed by a spring 52. It consists of a check pawl 53 that is always locked to the ratchet wheel and a check release means 54 that releases the pawl 53 from the ratchet wheel 51 as necessary.
Further, the release means 54 includes a spring 57 having a larger spring force than the spring 52 in a guide tube 56 that is integral with the main body and has a radial groove 55 at the tip.
A push-in pin 58 is inserted, and a knob 60 having a stopper 59 fitted into the groove 55 is fixed to the rear end of the pin, as shown in FIG. Move the stopper 59 to the cylinder 56.
When necessary, the push-in pin 58, which is engaged with the end face of the holder and pulled away from the non-return pawl 53, is moved forward by rotating the knob and fitting the stopper 54 into the groove 55. 53 in the direction opposite to the spring 52 to disengage the ratchet wheel and check pawl.

The reason why the above roller reversal prevention mechanism was adopted is that if some force is applied and the cable retreats immediately after the limit switch 34 is activated, the limit switch will be activated again even though the roller has not made one revolution. The same signal as when rotating is sent, which may cause errors in the measured length, so this is to prevent this and improve measurement accuracy.
Further, the reason why the non-returning means is provided is that it is conceivable that it may be necessary to intentionally move the cable backward.

Note that the claw 53 may be released manually by protruding the rear part of the claw from the casing of the main body, and in this case, the claw 53 rotated in the opposite direction can be hooked and held. If a locking device is provided on the casing, the released state can be maintained after release without any manual effort.

Further, it is desirable to provide a backing plate 13 behind the arm 12 to regulate the insertion length of the arm into the conduit and to stabilize the fixed state of the main body.

Further, in order to further enhance the slip prevention effect of the length measuring rollers, the outer peripheries of the rollers 31 and 32 may be knurled, or a brush 14 may be provided to remove deposits from the roller contact surface of the cable. In addition, it is desirable to arrange guide rollers 15 and 16 in front of the length measuring roller.

〔effect〕

As explained above, the length measuring device of the present invention has a clamp mechanism that presses against the inner surface of the pipe in the arm integrated with the main body, so that it can be used while being fixed to the pipe opening.

In addition, the length measuring rollers are arranged opposite to the center of the cable, and a pressing force is applied to one of them, and the length measuring rollers are prevented from reversing when the cable advances.
Accurate length measurement is possible even for cables with small diameter and low rigidity.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing how the length measuring device according to the present invention is used, and FIG. 2 is a sectional view of the length measuring device according to the embodiment.
Fig. 3 is a sectional view taken along the - line in Fig. 2, Fig. 4 is a perspective view showing the length measuring roller, Fig. 5 is a perspective view showing the non-returning means, and Fig. 6 is a conventional length measuring device. FIG. 3... Cable, 4... Conduit, 10... Length measuring device, 11... Main body, 12... Arm, 13... Backing plate, 14... Brush, 15, 16... Guide roller, 20... Clamp mechanism, 22... Movable contact, 23... Fixed contact, 24... Screw shaft, 25
... Wrench, 30 ... Length measuring mechanism, 31, 32
...Measuring roller, 33...Cam roller, 35...
Limit switch, 40... Pressing means, 41...
Spring, 42...Adjustment screw, 50...Roller reverse rotation prevention mechanism, 51...Rawl wheel, 52...Spring, 53...Return check pawl, 54...Return check release means.

Claims (1)

[Claims] 1 A clamp mechanism that secures the main body to the pipe opening by press-contacting the contactor provided on the arm to the inner surface of the pipe, and a pair of rollers facing each other around the cable, detecting the rotation speed of one of the rollers and converting it into an electrical signal. A cable length measuring mechanism consisting of a converting detector, a counter that integrates and displays the signal from the detector, or a calculation display that converts and displays the integrated signal into length, and the other roller mentioned above is brought into pressure contact with the cable. a pressing means;
A cable length measuring device fixed at a pipe entrance, comprising a ratchet wheel integrated with one of the rollers, and a releasable roller reversal prevention mechanism consisting of a non-return claw urged by a pressing body and locked to the ratchet wheel.