| 摘要 |
<p>The profile beams are designed for making of extensible masts. They are of profile type so that they may be partially inserted in each other due to which there is no need for supplying different profile beams for the different fixed, intermediate and mobile columns and for this reason the mast is designed as a structural integrity of one type of profile beams, thus reducing any production complications and costs. As there is a pair of arms on each side of the central part of the profile beams, a double support is supplied for the upper and lower set of rollers. The profile beam (1) includes a central part (2) having two opposite side surfaces - first (2a) and second (2b), and to the first side surface (2a) essentially a first pair of arms (3) is fitted having identical specified length (L), and to the second side surface (2b) essentially a second pair of arms (4) are fitted perpendicularly to the second side surface (2b). Arms (3) of the first pair are fitted at a specified distance (D) from each other, and arms (4) of the second pair have identical lengths (1) and are fitted at some specified distance (d) which differs from the first distance (D) between arms (3). 8 claims, 10 figures</p> |
