Unknowingly, almost everyone has already seen them, at the latest they were featured as "important margin" during the Soccer World Championship broadcasts: Light construction cranes for movie and television filming. Thanks to their viewing height and maneuverability, in the case of soccer and other types of sports broadcasts, they are located behind the goal, or in other exposed locations, and allow brilliant images of the on-going events of the game. Such cranes for the guidance of a camera must be quickly assembled, easily controlled, and must also be able to reliably support even heavier cameras with a large (tele-) lens. So-called remote heads, remotely controlled camera supports at the tip of the crane, allow the precise alignment of the recording devices. In order to keep the camera’s load capacity at the long lever arm of the boom as large as possible, all components must be of a very light construction. In this regard, small EC motors ensure movement and compact high performance at low mass.
Especially with movie filming, as well as in the everyday television business, quickness and flexibility are key issues. In order to provide the director and camera man improved views, and therefore the viewers with an improved overview, MovieTech AG builds modern light construction cranes under their brand name ABC Products. Depending on the model and customer request, these cranes can be equipped with boom arms from up to 12 m. Yet, the mechanics can be assembled by only one person in 20 minutes. Smaller models fit into a tote bag, and can be transported easily to the filming site, which is a substantial advantage for documentaries. In order to be able to variably utilize the camera at the crane end, one camera support is integrated per quick connection. This remote head then allows the turning and pivoting of the camera, optionally also the zoom and focus functions. In order to be able to perform these movements as easily, reliably and efficiently as possible, the crane specialist works in cooperation with the FAULHABER small motor expert. In this manner, the compact device support for precise camera pivots was created.
Camera Technology makes high Demands
Modern camera technology makes specific demands of light construction cranes. The recording devices achieve a weight of several kilos without any problems. Depending on the job site, additional weight is added by heavy telephoto lenses. This poses two challenges for the crane: First, the boom must be able to naturally support the weight, second, all movements of the camera must obey the operator’s commands fluently and without any delays or bouncing motions with dynamic recording. The crane specialist solved the problem for the larger professional grade devices by means of a special alignment of the controllable crane heads. In this way, the smaller remote head Alex can carry up to 15 kg of load capacity with a dead weight of only 6.8 kg, its larger brother Pelé even up to 30 kg at a net weight of 9 kg. The total mass of up to 20 kg at the 12 m boom is moved safely and precisely via efficient EC servo motors with a planetary gear. Current events and good recording is “captured” manually only, therefore a camera man controls the pivoting movements during filming by hand via a control console. In order to provide the operator direct feedback of his actions via a screen, the motors must accelerate without delay. However, quick does not necessarily mean with a jerking motion, a soft utilization of force is key, any nodding, or rocking motions of the camera by too hard of an acceleration would result in blurred images. The drive used by the small motor specialist from Schönaich makes allowance for this. Markus Schärtel of Movie-Tech remarks: “A large, popularly utilized advantage of the EC motors is that they can accelerate using ramps that are preset and adjusted to the respective camera weight. In this manner, the system’s pivoting tendency is reduced to a minimum”. An optional moisture attenuation additionally calms the camera at the crane boom. In this manner, a silky-smooth start-up, and a slow pivoting that is barely recognizable by the eye, are possible. Even with television filming, sharp images are the result.
Small, powerful, creative
The reason that two EC motors were selected per remote head was for two reasons: The drives are innately sturdy and reliable. With exception of the bearing, there are no expendable parts. In this manner, several thousand maintenance-free operating hours are possible. The motor can be mounted, and forgotten, since no maintenance is required. Thanks to electronic commutation, the drive is very flexible. Whether pivoting direction, rotation speed, torque, or complex “movement programs” of several of these variables, an EC motor reacts quickly and precisely to incoming control signals or specifications.
That is one of the reasons why it is also a very inexpensive drive solution. Thanks to its maintenance-free nature, compact dimensions, and a planetary gear series adjusted specifically to it, it offers a lot of performance for little money. Advantages: The power level is individually adjustable by the user, the user can issue commands to the motors without any delay via the crane controls. The creative specification gained from experience for the ideal positioning of the camera is quickly transmitted by the flexible drive. In this manner, drive and human operator of the remote heads are a perfect match, the crane becomes the extended arm of the camera man. Modern EC small drives are especially suited for applications constructed as small and compactly as possible or in which special consideration must be given to weight. Thanks to the flexible actuation and the delay-free reaction of the motors, even dynamic application sites are no problem. The quick, sensitive controls avoid distracting start-up rocking motions, which is an advantage that is not to be underestimated as opposed to other drive concepts. Thanks to a large variety of models and extensive accessories, an optimum drive concept is therefore possible for practically any application.