Patent GB-722005-A (GB)
Title: Apparatus for erecting a sectional mast
IPC: E04H12/18
Filed: 1951-05-22
Abstract: 722,005. Erecting masts. BEATTY BROS., Ltd. May 22, 1951 [April 13, 1951], No. 11886/51. Class 78 (2). [Also in Group X] Apparatus for erecting and dismantling a sectional mast of the kind described in Specification 691,146, [Group X], and carrying television antennµ comprises a tripod 11, 12, 15 of height greater than the length of one section but less than the length of two sections, removable cross-members 13, 14 connecting the legs 11, 12, a pulley 16 mounted on the top of the tripod, a manually-operated windlass 18 mounted on the leg 15 and a cable 45 which is wound on the winch, passed over pulley 16 and carries a hook 46 at its free end to engage the lower end of the mast. The leg 15 is pivoted between the upper ends of the legs 11, 12 by a pin 17 on which the sheave 16 is mounted. The winch 18 has an extension formed with channels 28 ... 31, Fig. 4, which are used in dismantling the mast. Sheaves 41 ... 44 mounted on the leg 15 are also used for this purpose. Releasable means such as a pawl 25 and ratchet wheel 23 hold the windlass against rotation in one direction. In the process of erection the television antennµ shaft 32 is first mounted on the top section 10a and this section is attached to the next lower section 10 in which a guy plate 33 has been inserted. Temporary guy ropes 34 ... 37 are then attached by hooks 38, Fig. 5, to the section 10a and led around sheaves 47 ... 50 anchored to the ground to a snubbing post (not shown). Each hook has an arm 38a to which is secured a releasing cord 39. Sections 10a, 10 are then placed in upright position between the legs 11, 12 and the hook 46 attached to the bottom of the lower section. One operator then holds the ropes 34 ... 37 to keep the mast erect and another operator actuates the winch until the bottom of section 10 is raised sufficiently to allow the next section 10b to be inserted beneath and connected to it. Another guy plate 33 is inserted in the section 10 and permanent guy wires 58 ... 61 are connected to it. The process is repeated until a mast of the desired height has been erected. A base member 62 is attached to the bottom of the lowest section and secured to a foundation. The wires 58 ... 61 are then secured to the anchors 54 and the wires 34 ... 37 removed. The cross-bars 13, 14 are detached to allow the removal of the tripod. When the mast is to be dismantled, an operator climbs it and reattaches the wires 34 ... 37. These wires are first passed around the sheaves 47 ... 50, then around the sheaves 41 ... 44, and then each wire is given one turn only through one of the channels 28 ... 31 in the same direction as the winch will be turned to lower the mast. The winch is now rotated to bring the hook 46 into position for attachment to the bottom of the mast. During this operation the guys are kept taut by the operator. When the mast is supported by the cable 45, the base 62 is removed and the winch is allowed to rotate until the mast is lowered through a distance corresponding, to the height of the base. The hook is removed and the cable wound on the winch so that when the hook is attached to the lower end of the next section, the mast will be supported by the cable and the bottom section can be detached and removed. These operations are repaeted until the mast is dismantled. Specification 722,086 also is referred to.