Patent GB-190802502-A (GB)
Title: Improvements in, or relating to, Fire Ladders and the like.
Inventor: MERRYWEATHER JAMES COMPTON
Filed: 1908-02-04
Granted: 1908-11-26
Abstract: 2502. Merryweather, J. C. Feb. 4. Fire-escapes.-Relates to motordriven mechanism for angularly raising or lowering or for extending or collapsing a telescopic ladder of the turntable type carried by a motor-propelled or other vehicle. In the form shown in side elevation in Fig. 2 and plan in Fig. 4, the turntable b carrying the fulcrum frame f of the ladder is mounted at the rear of an automobile, the propeller shaft of which drives a vertical shaft e through a universal connexion d and reversing- gear g, h of the bevel-wheel type, the shaft e passing through the centre of rotation of the turntable b. The shaft e may be driven in either direction by causing a clutch member i, operated from a hand-lever j, to engage with either of two coacting members g<1>, h<1> rotating with the reversing-gear g, h in opposite directions. On the upper end of the vertical shaft e is a worm k engaging with a pair of oppositelydisposed worm-wheels m mounted on horizontal shafts m<1>, which may be alternatively clutched to their driving worm-wheels m by means of clutches m<2>, m<3> operated by a three-armed lever n connected to a hand-lever n<3>. To each of the shafts m<1> is secured a pinion o, these pinions driving transverse shafts p<1>, q<1> through spur-wheels p, q respectively. The shaft p<1> carries drums p<2> for winding wire ropes to raise and lower the ladder, and the shaft q<1> carries drums q<2> for the ladder.extending ropes. The ropes from the drums p<2> pass over circular ropeways, so that the pull is exerted with constant leverage. The angular lowering of the ladder and its collapse telescopically may be effected under the action of gravity by operating the clutches m<2>, m<3> and applying band brakes to check the movement of the ladder, but the use of such brakes is preferably avoided by the employment of the free-wheel device shown in Figs. 5 and 6, whereby the return movement is effected by simply reversing the direction of rotation of the driving-gear. A disk is keyed to the drum-shaft p<1> or q<1>, and a similar disk s<1> is attached to the disk s at a distance therefrom by bolts s<2> and spacing-blocks s<3>. These disks are formed with inclined roller-ways s<4>, in which are mounted rollers t held in place by a ratchet-ring t<1> coacting with a pawl t<3> carried by the fulcrum frame f. The spur-wheelp or q is secured to a sleeve u provided with a roller-driving plate v located between the disks s, s', the arrangement being such that when the gearing is rotated to wind up the rope, the spur-wheel p or q causes the roller-driving plate v to force each of the rollers t into the narrower end of its companion rollerway s', and thereby cause the rotation of the drumshaft p<1> or q<1> and the ratchet-ring t<1>, the pawl t<3> riding over the teeth of the ring t<1>. When the latter is to be lowered and collapsed, the driving- gear is reversed, thereby causing the plate v to disengage the rollers t and allow the disks s, s<1> and the drum-shaft p<1> or q<1> to rotate in the unwinding direction. If the driving-gear is stopped, the freewheel becomes locked, and further movement is prevented by the pawl t<3>. The worm-wheel shafts m<1>, Fig. 4, may be formed with squared ends m<4> for the reception of cranked handles, by means of which the ladder may be operated by hand if the motor fails. The ladder is locked in the elevated position by means of a pawl and a circular ratcbetrack. The extent to which the ladder has been extended or collapsed is indicated by a pointer connocted by bevel-gear to one of the worm-wheel shafts m<1>. The ladder may be angularly elevated by means of screwed spindles passing through swivel nuts fixed to the ladder, instead of by means of winding-gear. In a further modification, the angular raising and the extension of the ladder may be performed simultaneously, the clutches m<2>, m<3> being operated by separate bell-crank levers, instead of by the three-armed lever n.