DE20114200U1 - Measuring device for contact wire strength measurement - Google Patents

Description

The invention relates to a device for measuring the thickness of the contact wire of an overhead line.

An overhead line system is installed above the tracks of railways with electric traction for the purpose of supplying electricity. The electrically operated traction vehicles take the energy they need from there via the contact between the pantograph and the overhead contact wire. The wear caused by the mechanical contact and the flow of current leads to a reduction in the cross-section of the contact wire and thus to a decreasing tensile strength of the contact wire. When a lower wear limit is reached, the old contact wire must therefore be replaced with a new contact wire or individual faults must be repaired.

In the past, there have been many different approaches to checking the contact wire thickness. In the simplest case, the contact wires were checked using commercially available micrometer screws, which are commonly used as measuring instruments in mechanical engineering. The disadvantage of this, however, is the relatively high time required to manually adjust the micrometer screws to the contact wire thickness and to read the measurement results from the very small display scales. As the fitters usually have to wear fairly coarse work gloves for reasons of occupational safety, using the measuring devices is cumbersome and time-consuming. A particularly negative aspect is that the measurement results can only be read with the help of strong external light sources, especially when working at night. In addition, the resilience of the precision mechanics is only very limited for rough construction site use.

Another very simple measuring device is gauges that can be pushed or plugged onto the contact wire with a wedge-shaped tapered notch on one side. The thickness of the contact wire at the measuring point can be read off the upper edge of this notch using an engraved or printed measuring scale. Despite their mechanical robustness, these gauges have not proven themselves to be effective because they tend to jam when combined with the typical geometry of an overhead contact wire.

Devices based on the principle of magnetic layer thickness measurement are also known. However, this requires a power supply for the measuring devices.

The most serious disadvantage of all these measuring devices is the need for a de-energized state of the contact line, since the measurement can be carried out

The operator must work in the immediate vicinity of the contact wire. For the same reason, the use of suitable lifting or climbing devices is also necessary for the measuring work.

To avoid these disadvantages, optical or laser-based methods have been developed that enable continuous measurement even when the overhead line system is switched on. However, these measuring devices still produce system-related measurement errors, particularly in the area of guy wires, section insulators, clamps and track crossings, which make spot-based follow-up measurements necessary.

The invention is based on the task of developing a device for measuring the thickness of the contact wire of an overhead line, which primarily enables use even when the overhead line system is live. At the same time, it should be easy to operate even in adverse weather conditions or poor visibility and require little logistical effort for its use. The device must function independently of an external power supply, not require any special knowledge to operate and no accompanying use of lifting or climbing devices should be necessary. Low acquisition and manufacturing costs should ensure that the device is available in the tool inventory of every inspection or maintenance team and that complex central planning with the associated pre-ordering and delivery problems can be avoided.

This object is achieved according to the invention in conjunction with the preamble of claim 1 in that a known insulating rod or earthing rod has a mechanically acting measuring device that can be operated by a person standing in the track area. This represents a new quality, since it is now possible to measure the contact wire thickness using a device with a simple design even when the supply voltage is switched on.

The inventive concept is effectively supported if the measuring device consists of two pliers-like, articulated probe blades, whereby one of the two blades ensures a positive fixation of the contact wire and one of the two blades carries out the probe-like positioning movement on the contact wire to be measured, which is relevant for the measuring process. This allows remote control by an employee in the track area without the use of auxiliary energy via a corresponding mechanical operating mechanism.

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An advantageous embodiment of the inventive concept provides that the display is also shown via a mechanical link on a scale that is easily recognizable for the operator. By using appropriately cranked elements, it is also possible to choose a disproportionately large display scale in the vicinity of the limit value to be checked. This enables the operator to read the value directly even in unfavorable visibility conditions, such as when working in the area of a curve or in dim lighting conditions.

Finally, it is particularly advantageous for the subject matter of the invention if a cable pull used to release the measuring device in the measuring position runs inside the hollow earthing rod. By avoiding a component that hangs loosely or slackly in the outer area, the handling of the device is improved.

The inventive concept is described using an embodiment shown schematically in Figure 1.
The device consists of a two-part, height-adjustable insulating rod (1) with a hollow interior. One possible material is glass-fiber-reinforced polyester, which can handle the high potential difference between the contact wire and the ground without voltage flashover. A measuring device is attached to the tip of the rod, which consists of a fixed lower blade (2) and an upper blade (3) that can move via a pivot point. This upper blade is in turn connected to a pointer (7) via a deflection rod (6), the pivot point of which is designed so that even small diameter changes in the area of the limit value to be checked result in a large display deflection (8).
The two cutting edges can be opened (e.g. to insert or remove the contact wire (10) into the measuring notch (9)) by pulling the release cable (4), whereby the return spring (5) is simultaneously stretched.

This return spring (5) ensures, by means of the deflection rod (6), that the upper knife in its basic position always approaches the lower fixed knife in a closing movement.
Not shown in the drawing is the possibility of inserting the release cable (4) into the interior of the hollow insulating rod by means of pulleys in the area below the measuring device and leading it from there to the operator.

List of reference symbols:

1 insulating rod, height adjustable

2 lower contact knife of the measuring device (rigid)

3 upper contact knife of the measuring device (movable)

4 Release cable

5 Spring

6 Deflection rods

7 measuring pointers

8 Display

9 Measuring notch

10 Contact wire (cross section) 15

Claims (4)

1. Device for measuring the thickness of the contact wire of an overhead line, characterized in that a known insulating rod or earthing rod has a mechanically acting measuring device which can be operated by a person standing in the track area. 2. Device for measuring the thickness of the contact wire of an overhead line according to claim 1, characterized in that the measuring device is constructed from two probe knives which are connected to one another in an articulated manner like pliers, one of the two knives fixing the contact wire in a form-fitting manner and the second of the two knives carrying out a probe-like positioning movement on the contact wire to be measured which is relevant for the measuring process. 3. Device for measuring the thickness of the contact wire of an oil line according to at least one of claims 1 to 2, characterized in that it has a measuring pointer connected via deflection rods to the knife which carries out the adjusting movement relevant for the measuring process, for displaying the determined contact wire thickness on a scale which can be read by the operator. 4. Device for measuring the thickness of the contact wire of an overhead line according to at least one of claims 1 to 3, characterized in that a cable pull serving to release the measuring device in the measuring position is arranged within the hollow earthing rod.