| 摘要 |
<p>A camera crane comprises a telescopic support which can be extended and retracted at variable speed, with proportional and simultaneous adjustment of its counterweight (2), so that the crane is maintained constantly in stable equilibrium. To ensure that the horizon of the image taken by the camera is maintained constantly horizontal, a tachometer generator arranged at the tilting centre (1) of the crane reads the tilting speed and reproduces it at the suspension of the swivelling and tilting heads by means of an electric amplifier and an electric motor. The axes of the swivelling and tilting heads are rotated directly, i.e. without gears, solely by the magnetic field. The movements of the camera can thus be applied with high precision.</p> |
