TELESCOPIC MASTS.

Oamaru Mail, Volume XXXIX, Issue 10957, 23 December 1911, Page 3 (Supplement)

TELESCOPIC MASTS.

A mast eighty feet tall that can b<> shut up like a telescope and carried about by a couple of men is plainly a handy thing to have wherever a temporary observation tower or wireless station i's' needed.., In fact,. the military use of wireless telegraphy has practically demanded-something of the kind, so it had to be devised. Europe has produced it. The qualities required in such a devise are that it.must be rigid, tall, easily reduced to small compass, and quickly put in place. Cosmos describes the new mast, which may be,used for many purposes, even for a derrick, and gives the following details.that will permit almost any-American engineer to design one: —, "These masts, known as the 'Comet' telescopic masts, are formed of a series of tolescoxiic tubes mounted one on the the other, with a play of 1-10 to 2-10. inches and displaceable by means of a steel ribbon moved by 'appropriate mechanism.

'The different segments, which dii minisli considerably in diameter from below upward-. . . . alsc lessen in thickness, so as to realise the best possible utilisation of the material and to obtain- the maximum strength with the minimum of weight. "Extension is" effected, as stated above, with the aid of a long ribbon of soft steel 1-15 to 1-5 inches thick, which engages the greatest diameter if each of the tubes, being fastened" affile end. of the last. The ribbon has a median row of equidistant perforations ..... in which engage the teeth of a hoisting wheel placed at the base of the mast. This wheel, with another, having indentations corresponding to the teeth of the former, and a drum supporting the steel ribbon and handle, constitute all the mechanism for hoisting and lowering; the whole is mounted between two supports of cast steel, bearing .-.t the upper part of the foundation of nie mast, formed by a ring of wrought ste'el. The ascent or descent- may lie arrested in any position; a special device pre-

vents the various sections from starting before their turn, so that the mast lias complete rigidity even whenonly partially raised. This rigidity is assured for the ribbon by making it exactly equal in width to the diameter of the part where it is found, for the various heights; it thus acts like a rigid viece, not being able to move sideways, break, or bend. The applications of this kind of mast are numerous. One of the most interesting would appear to be its use in wireless telegraphy, as a support for the antennae. It may serve the purpose, also, of an observation mast, or as a stndard for projectors, searchlights, signals, etc A mast of 200 to 250 pounds, reaching, when fully extended, 80 feet in height, is only about 10 feet long when lowered, and the time required for hoisting it is only a few minutes.

"Telescopic masts may also be utilised on shipboard, and for the support of protective nets against torpedoes. They are valuable in military operations, being easily transportable and lending themselves to various uses. As derricks, they can support up to 6,500 or oven 12,000 pounds, according to the test made by their constructors."