Steam is now made to perform almost everything in the way of heavy
labor, to the saving of muscle and energy that may be more profitably
employed; and since inventive genius has devised means of governing
steam with absolute accuracy, there seems to be no limit to its
economical application.
A recent invention in steam engineering, which exhibits in a marked
degree the controllability and adaptability of steam, is Mr. Herbert
Wadsworth's steam tiller, an engraving of which we present herewith.
[Illustration: Fig. 1, 2, 3.]
This machine (Fig. 1) is provided with a steam cylinder, similar to
the cylinder of a steam engine, containing a piston, the rod of which
is attached to a crosshead, A, that slides on ways, B, secured to the
bed supporting the cylinder.
The tiller, D, as it is carried to starboard or port, slides through a
socket, E, pivoted to the crosshead.
The motion of the rudder is communicated to the steam cut-off by means
of the shaft, C, crank, J, rod, K, crank, I, and the hollow valve
spindle. When the tiller is amidships the valve handle, H, is at right
angles to the cylinder, and parallel to the tiller. By moving the
lever, H, to right or left, steam is admitted to one end or the other
of the cylinder, which, acting on the tiller through the piston,
piston rod, and crosshead, moves the rudder; and when the rudder
reaches the desired position the cut-off will have been moved the
amount necessary to prevent further entrance of steam. When the rudder
is influenced by the waves or by the expansion or contraction of
steam, the cut-off alters its position in relation to the valve and
automatically arranges the steam passages so that the piston is
returned to its proper position. The details of the cut-off are shown
in Fig. 2; the valve, G, which covers the cut-off, F, acts like a four
way cock. The spindle of the cut-off, F, is connected with the lever,
I, and is moved by the rudder, as already described. By enlarging or
gradually narrowing the ends of the steam ports great rigidity or
elasticity may be given to the hold of this engine, according to the
requirements of the particular vessel.
Few and simple as are the parts of this machine it is possible, by
balancing the valves and suiting the diameter of the cylinder to the
work to be performed, to overcome great resistances with a slight
effort. The inventor says that this system of valves is considered by
experts to be novel and very valuable.
In Fig. 3 is shown a pattern of a slide valve suited to special
purposes. Its working is essentially the same as that of the valve
already described. The ports are set side by side, parallel with the
sides of the valve. The supply port is in the middle, the other ports
lead to opposite ends of the cylinder.
[Illustration: Fig. 4.]
In Fig. 4 is shown another application of the controlling valve and
cut-off described above. Two oscillating steam cylinders are employed
in working the rudder. They are placed on opposite sides of the chest,
A, and are supplied with steam through the controlling valve, B. The
piston rods of the two cylinders are connected with cranks placed on
opposite ends of the shaft, C, at right angles to each other. Upon
this shaft, half-way between the pillow blocks which support it, there
is a worm which engages a toothed sector, D, on the rudder-post, E. To
an extension of the rudder-post is secured an arm, F, which is
connected with the arm, G, of the controlling valve. By shifting the
lever, H, the supply of steam to the two cylinders may be increased or
diminished, or its direction may be changed, so that the engines will
be reversed or stopped. This engine is remarkable for its simplicity.
The cylinders may be detached and changed if required, one size of bed
answering for three different sizes of cylinder, which may vary only
in diameter, the stroke being the same, so that the castings for
engines of different power are the same except in the matter of the
cylinders and pistons, and all the parts are interchangeable--a
feature of modern engine building that cannot be too highly valued.
Further information may be obtained from Herbert Wadsworth, 26
Merchants' Bank Building, 28 State street, Boston, Mass.
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