| 摘要 |
<p>643,885. Load-handling machines. PRODUCTION FACILITIES (FILMS), Ltd., RAWNSLEY, D. W., and GREEN, E. R. Oct. 20, 1947, No. 28018. [Class 78 (iii)] [Also in Group XX] A mobile tower for supporting kinematographic cameras or other optical apparatus comprises a platform 4 raised and lowered between uprights 3 extending from the base 1 of the tower by power means, the base comprising wheels 6 adapted either to bear upon the ground for transport or to be raised from the ground so that the tower is supported on fixed members. The fixed members preferably comprise jack-actuated feet 5, wheels 6 being freely rotatable on axes fixed vertically but capable of swivelling. The platform is supported between vertical guides 22 in the uprights 3 by means of four slippers 15 secured to two uprights 20, Fig. 4, extending upwards from the platform and forming part of a framework which also includes a transverse beam 11. Each slipper 15 consists of a U- shaped channel member, Fig. 4, to one side of which is fixed a plate 31, the other side being provided with a similar plate 23 loosely attached to the slipper by dowels and by a bolt 25. Plate 23 is kept in light frictional contact with guide 22 by means of a spring 26 adjustable by nut 28. A taper jib 16 is supported in brackets 32 on each slipper for sliding vertically, so that movement of a lever 17 operating a short double arm crank 18 at each side of the platform which is connected through links 19 to the jibs at that side, moves them in a direction so as to press on the plates 23 of each slipper, causing binding on the guide 22 and consequent locking of the platform. Cables 7 attached to the platform pass through apertures 12, Fig. 4, in the slippers 15 and over pulleys 8 to a winch or hydraulic ram in the base, counterweights 13 sliding on guides 14 being included in the vertical stretches of the cable in the uprights 3. The wheels 6 at two corners may be coupled together for steering, while the other two wheels or wheel pairs are free to trail. Alternatively, the wheels may be flanged and on fixed axes, one at each corner of the base, for running on a rail track and a further set of flanged wheels on axes at right angles to the first set may be arranged to be lowered by hydraulic jacks to engage cross-over rails leading to a parallel track. In all forms the jackactuated feet 5 may be replaced by fixed feet and the wheels may be raised and lowered by separate jacks or a single jack coupled to all the wheels.</p> |
