How to use the theodolite? Device, verification and alignment of theodolite

The quality of the building object is determined by different criteria. In the list of mandatory items, when performing an expert examination, the following items appear: the composition of the material, the reliability of the joints, the compliance of the structures with safety requirements, etc. Separate consideration is also given to the restraint of the geometric lines for which the installation works were carried out. To prevent miscalculations and deviations in the process of building structures, engineers use theodolite. This is a measuring device that allows you to assess the correctness of the formation of angles in the vertical and horizontal. The device, although it is a small device, requires special preparation. Therefore, before the construction activities, it is necessary to deal with the question of how to use the theodolite in order to obtain the most accurate results.

Theodolite device

The classic design is a combination of a sight pipe and pillars that hold it. To control guidance, a special sight is provided - similar settings can be performed differently depending on the model. The pipe allows to measure the vertical angle, and operations with the horizontal are performed by means of the appropriate circle, which includes the limb and alidade.

Using magnifying optics, the surveyor can view the target object at large distances from it. And not necessarily such devices must be included in the basic kit. Increase the range of the tool without loss in accuracy can be done with a special optical tooling. For ease of viewing, the instrument is provided with an eyepiece that has a cross-section of scales. In addition, geodetic models are provided with protective means. In particular, the theodolite ruler, intended for fixation in one position, can have a casing preventing the risk of changing the position.

Principle of operation of the instrument

In general, the work of the instrument can be characterized as an analog of the function of classical levels and goniometers. But in this case, the sophisticated "stuffing" allows you to perform similar actions with higher accuracy and convenience. All operations are based on the principles of geometric calculations. The initial data are the indications received during the installation of the instrument. Actually, the main part of the work consists in the correct setting of the instrument. Further, the principle of theodolite depends on the type of equipment - it can be a traditional optical, electronic or laser apparatus. In the first case, the user must independently establish physical objects that will act as reference points for calculations. If the electronic model is used, zero marks will be fixed automatically. In the future, everything depends on the object for which the calculations are made. Information about the required operations is also given, and in a few moments the device issues information about errors and deviations. Now it is worthwhile to consider in more detail the most common variations of this device.

Varieties of theodolites

The most common optical theodolite, which includes a microscope, providing the possibility of visual determination of errors. From the point of view of ergonomics and accuracy of measurements, this is the least profitable option, albeit the cheapest one. The user of such a tool is reported to independently determine the deviations in the horizontal and vertical planes in relation to the object being installed. The drawback of optical models is the dependence on external conditions. For example, many novice surveyors are wondering how to use the theodolite if daylight is not enough. Only the optional add-on in the form of a mirror for illumination will help. It can also be built into the body of the device, but in any case it should be at hand.

Electronic models are equipped with sensors that read the measurement readings and translate them to the display. That is, the user does not need to look at the screen and independently calculate the optical readings. However, such models are sensitive to mechanical influences. So, in portable operations, the ruler of the theodolite in the form of alidade and tribrach will help to eliminate the risk of damage and strikes. In this case, you can not take the device by the telescope. As for laser modifications, they are a subset of the electronic device. The differences of this device include the possibility of a more accurate laser arrangement of control points.

Verification of the theodolite at the round level

Most often in the work with the theodolite, verification of the round level and the grid of threads is required. In the first case, the calibration is performed in order to ensure the parallelism of the two axes - from the circular level and the level rotation plane. It should be noted that calibration and alignment of the theodolite are always performed with the help of special regulators. In this case, the verification is realized by manipulating the lifting screws, which allow the bubble to be brought to zero-point. In parallel with this action, the mutual position of the two target axes is monitored.

Verification of the grid of filaments

In the case of a grid of filaments, the aim is to ensure that the horizontal line is perpendicular. In this case, the vertical bar must go parallel with respect to the rotation axis of the level. Verification on the vertical stroke is carried out using a plumb line, suspended 25 m from the level. On the round level, you need to bring the axis into a steep position. Next, the two axes are aligned in accordance with the calibration requirements. With respect to the horizontal, it should be noted that this parameter is guaranteed by the manufacturer. However, in some models, theodolite calibration and alignment can be performed in a complex manner by changing the play in the holes of the fixing screws. Experienced surveyors can change the positions of such axes, if this possibility is provided for by the design.

Tool alignment

This procedure is performed to eliminate deviations caused by inaccurate tuning of the mechanical nodes of the instrument. For example, the reason for doing this type of calibration may be an incorrectly adjusted cylindrical level of theodolite, in which the alidade shows an inadmissible displacement of the bubble. Directly adjusting provides for the regulation of the lead screws, which, in turn, correct the parameters of the alidade so that the horizontal circle becomes on the readings with the correct count.

Angle measurement

At the points where the erection of building structures is planned, it is necessary to provide a temporary framework. With the help of a theodolite, an eyepiece is directed to one of the selected points of the installed structure, which will be taken as zero. In order to provide correct indications initially, one should consider how to use the theodolite on uneven terrain. To do this, it is important to ensure in the first place a reliable basis. Further, support pillars are introduced into the ground, it is also desirable to perform additional fixation.

Then you can start calculating the angles. With respect to the starting point, a position is selected from which further calculations will be made. This can be a vertical angle, and a horizontal calculation. A scale with coordinates will allow to make measurements with a small error. In the case of electronic models, calculations are made automatically in a few seconds.

Manufacturers of theodolites

This segment can be described as highly specialized and designed for professional design. Accordingly, there are few companies in this niche. Traditionally, quality measuring equipment for the construction industry is produced by ADA, in the line of which it is possible to find models for different tasks. For example, specifically for vertical design, the ADA Vertical line is provided. For universal use, the theodolite Vega Teo is suitable, with the features of which include the presence of two displays that provide calculated data with high accuracy. However, for ergonomics and functionality of such equipment will have to pay a lot of money - about 50-60 thousand rubles.

Conclusion

It would seem that standard goniometers and self-leveling devices can easily solve design problems. But as the construction technologies become more complex, the requirements to the accuracy of geometric measurements are also growing. Therefore, questions about how to use the theodolite and its high-tech equipment are encountered more often. It is not enough to have basic skills in handling the optical scale. To effectively use digital and laser gauges, you should also have an idea of calibration and alignment. The calibration, on which the accuracy of measurements depends, provides for the implementation of the associated settings of the mechanical part and the instrument optics. In the future, the increase in the complexity of design operations is reflected in the increase in the quality of construction projects, so the use of modern theodolites itself fully justifies itself.