Transferring control lines with a rotary laser. You’ve surveyed the plot, finished the fine marking and erected the batter boards at the edge of the excavation. You now need to transfer the control lines exactly and efficiently into the excavation. Classical batter boards are often still used for this. This procedure is simple, but inaccurate and time-consuming. A suitable rotary laser makes this job easier, delivers more precise results and saves time, and thus costs. This article describes the procedure step by step – from setting up the equipment to the perfect result.
1. Setting up the rotary laser
The rotary laser is fastened to the batter board on one side of the excavation with the help of a batter board clamp. Thanks to the notch in the tip of the clamp, the laser plane is automatically set up correctly exactly over the nail that has been hammered in. If a laser with so-called “manual rotor adjustment” is used, the correct position of the laser can be checked by turning the stationary laser beam downwards manually. The laser dot then lies exactly above the nail in the batter board. Tip: Use the spirit level in the rotor head for exact plumbing down.
The laser device is then switched on, and automatically generates a vertical, perfectly perpendicular laser plane.
2. Setting up the locking receiver
The locking receiver is the second point on the control line and is located opposite the rotary laser. The receiver can be set up above the control line either standing on its own or also fastened with a batter board clamp. It must be ensured that no objects obstruct the line of sight between the rotary laser and locking receiver. It should also be ensured when setting up that there is an unobstructed view into the excavation for transfer of the control line and alignment of the formwork. The locking receiver is then switched on, and the automatic locking mechanism activated. The laser is then controlled remotely by the receiver by radio so that the laser surface is locked in its centre. Please note: The locking receiver and rotary laser must be paired with each other ex works! As a result of this association, it is possible to use multiple different systems on one construction site at the same time without them influencing each other.
3. Practical implementation
Transferring the control line into the excavation
To transfer the control line into the excavation, the laser surface in the pit is scanned with a measuring receiver. It detects the light surface and shows the deviation depending on its version with the help of various LEDs and audible signal tones or directly on a display in millimetres. The line can then be marked in the excavation with, for example, a marking spray.
Levelling of formwork or components
Formwork and components are aligned analogously. The formwork element is first aligned roughly on the control line. It is then aligned finely with the help of a measuring receiver.
4. Selection of equipment
Basically, any rotary laser with sufficient accuracy, which can be used vertically and which allows remote control by a locking receiver can be used for the work described above. The GEO laser RL-79L was used in the video that can be viewed above. The RL-79L rotary laser is an all-round laser for generation of horizontal and vertical light surfaces and is capable of electronic self-levelling on 3 axes. Depending on requirements, it emits a stationary or rotating laser beam in laser class 3R. As variant RL-78L, it is available with lower power in laser class 2. Read more
The FE-53 was used as locking receiver. It can be used in combination with various GEO lasers for a variety of tasks. Its prime purpose is to lock the Y-axis (direction) of the laser. As soon as the rotating laser beam hits the receiver’s detection area, it is automatically directed to the centre and locked there. Read more
The LE-96 is ideal as measuring receiver. It receives a rotating laser beam and indicates its position to the light plane by way of two LEDs and various signal tones. Thanks to its robust design and totally waterproof construction, the LE-96 is the ideal companion for tough everyday use on construction sites. The short response time of the receiver and its good legibility make it perfect for all alignment and measuring work. Read more