Cranes and lifting equipment - Expo Paris 1867
The drawing shows one of those powerful lifting devices which are nowadays used in the ports for unloading ships.
The cranes installed on the banks of the Seine have familiarised the Parisians themselves with machines of this kind.
The ordinary crane - there are many fine specimens in the Park - consists, like the goat, of a winch and one or more pulleys. A rope is wound onto the winch, detached from it, passed over pulleys, lowered vertically, wound onto the groove of a mobile pulley with a hook, and then raised and attached to a fixed point. In addition, the whole machine can rotate around a vertical axis. Everyone has seen the manoeuvre. The crane is first brought into a position where the mobile pulley is placed directly above the boat to be unloaded.
After lowering this pulley, which forces the rope wound on the winch to unwind, the load is attached to the hook and the winch is turned: the rope is wound again and the load is lifted. When it has reached a sufficient height, the crane is rotated about its vertical axis until the load is suspended above the point where it is to be deposited; finally the winch is given over to the movement which the tension of the rope tends to impart to it; the load descends, and as soon as it is properly supported either on the ground or on the car which is to be used to transport it, it is unhooked to operate in the same way on another load.
The same devices are frequently used in workshops where very heavy bodies have to be moved, especially in machine-building establishments and foundries. Several cranes are set up for this purpose, the first of which picks up the part to be transported and brings it into the vicinity of the second, which in turn picks it up and carries it further, and so on. Cranes are also used to transport large pieces of iron from the furnace to the anvil and to hold them on the anvil while the hammers are working.
In Mr. Claparède's machine, the same principles apply in a slightly different way. Here the machine does not rotate about a vertical axis, but the winch, capable of a double movement in two rectangular directions, enables, as in the cranes just mentioned, the pulley to be brought just above the burden to be removed and then to drive it just above the point where it is to be deposited.
One could see on the bank itself, two steps from this machine, a machine of the same kind, but mobile on a railway, depositing on their mounts the large artillery pieces melted down at Ruelle, and which are now placed in battery at the entrance to the tunnel by which the bank communicates with the Park.
The machine exhibited by M. Claparèle is sold to the State Navy. Its strength is 40 tons.
©L'Exposition Universelle de 1867 Illustrée