FIRE-FIGHTING APPLIANCES.
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The Latest Productions from the Tilling-Stevens Works.
INa paragraph which appeared in our issue for January 25th last we mentioned that Tilling-Stevens Motors, Ltd., of Maidstone, had purchased from the Weybridge Motor Engineering Co. the whole of the ladder, fire escape and turn-table ladder business which was formerly carried on by Henry Simonis and Co. Although this turn-table type ladder is now used by several; fire brigades, it may be of interest to describe its salient features, as certain improvements have been carried out in its design.
By the courtesy of the company we were recently affordedan opportunity of inspecting and photographing an 85 ft. turn-table ladder fitted to a 50 lep. Till. ing-Stevenrs T.S. 4 type petrol-electric chassis. Incidentally, this company's petrol-electric chassis has been standardized by the London Fire Brigade for remounting all their turn-table ladders.
The maximum angle of elevationl of the ladder examined is 78 degrees. There are four ladders in all, one main and three sliding, and three men can be carried at the top at full extension and at the greatest angle; at 70 degrees one man can be carried at the top of each section, whilst at 60 degrees the load is limited to a single man at the top.
Normally, the ladders are carried in a horizontal position, and when it is desired to swing them up, two men pull on to chains attached at the rear for this purpose, their weight causing the ladders to tip up, using the top of the plumbing frame as a fulcrum. At each side ef the plumbing frame is a winding drum containing a coil spring, and attached to the end of the main ladder are two chains, which are autematically wound on to these drums by the action of the springs contained in the latter. Between the two drums is a ratchet gear, whicl prevents the chains unwinding,
and consequently keeps the ladder at the necessary angle, although provision is made for releasing this gear when required.
When at maximum tilt the base of the main ladder comes up against two
spring buffers. The slight additional movement rendered possible by these buffers enables the top of the ladder to be positioned within certain limits. The plumbing frame which supports the ladders is fulcrumed near its top, and can be adjusted by a square-threaded screw, supported by the main framework, and provided with a hand wheel. This is necessary in order to bring the ladder into a vertical position if the vehicle is standing on uneven ground.
When the ladder is in use the rear axle is locked to the frame at each side, in order to prevent the springs coming into action and causing the ladder to sway.
A 3 h.p. electric motor provided with the necessary gearing, and situated at the end of the main ladder, obtains its current from the generator Of the petrolelectric vehicle, which is provided with a shunt change-over switch for changing the current from travelling to ladderoperating. In order to keep the eurrent, constant, the engine is provided with a hand throttle with very fine adjustment.
The electric motor rotates a drum, which winds up a steel cable attached to the first moving ladder. The other i . two ladders are inter-connected with
the former, so that if a certain height has to be reached, each of the three moving ladders lift S to one-third of this height. In order to prevent over-winding, the motor is provided with a special cut-out gear, consisting of a .nut travelling on a square thread formed on the axle of the winding drum. As the latter rotates, the movement of the nut throws out a switch and also releasee dog clutch on the motor shaft, but this only happens when the maximum height is reached. Each ladder is provided with a pair of safety catches, which prevent it dropping when the winding is stopped. A dial shows the number of rungs lifted, and as each rung is separated by one foot from the next, this shows the number of feet which the ladders have been extended.. At each rung a bell is chimed, and when the ladders are fully extended the bell chimes twice. A plumb bob and graduated scale shows the angle of the ladders.
The turn-table has steel. balls fitted between it and its base, and the whole ladder can easily be turned by hand.
.• Geared to the winding drum is an oil pump of the gear type, which normally short. circuits through a stop valve, but when it is desired' to let the ladders down this stop valve is closed and the pump &eta as a brake, preventing the ladders from closing too rapidly. Auxiliary hand-operated gearing for locating the top of the ladder more exactly or for use in the unlikely event of a breakdown of the motor is also fitted.
A second vehicle of considerable interest was the utility wagon built for Neweastle-on-Tyne. In this case also a T.S. 4 type chassis is utilized. This machine was described as being the "one-man band" of the fire-fighting department. It is fitted with an emergency water tank, and a pump driven from the flywheel by friction. At the off aide is a power take-off, by which current from the vehicle generator can be tapped for various purposes, such as lighting buildings. A crew of 15 men can he carried, and all round the body are lockers for carrying chemical' firs extinguishers and life-saving devices snob as breathing apparatus. A light extension ladder is provided, and this can be employed up to a height of 35 ft.