IMPROVED MACHINERY FOR OPERATING SCULL PROPELLERS, FANS, AND OTHER DEVICES
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at
the Office of the Commissioners of Patents, with his Petition, on
the 9th August 1875.-A communication from abroad by George
Robert Moore, of Westford, in the County of Middlesex, and State
of Massachusetts, United States of America.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for " IMPROVED MACHINERY FOR OPERATING SCULL
PROPELLERS, FANS, AND OTHER DEVICES," to be as follows:-
This Invention is a mechanical movement applicable for working
sculls for propelling boats, fans for blowing air, and the like, and it
consists of a carrier for the scull, fan, or other object to be worked,
crossing the axis of the crank shaft by which it is worked, and having a
holder or regulator to prevent the rotation of the carrier, and thus
maintain the blade, fan, or other device to be worked in its working
position, the said holder or guide being free to oscillate on or in its
bearings or supports to accomodate itself to the movements of the

page_text: carrier which it holds. This holder or regulator for the carrier is
susceptible of various modifications. It may consist of two arms
swinging forward and backward on or in a circular way or guide
arranged in a horizontal plane, in case the blade or fan is to project
directly downward from the carrier or upward from it, or the guide or
way may be above the carrier and in a vertical plane, and the regulator
may consist of one arm extending up from the carrier to it, and the arm
may be a prolongation of the stem of the blade of a scull, or if it is a fan
the guide or way may be below the carrier for a vertical fan or at one
side for a horizontal fan.
Various contrivances of one or both of the rings of gimbals may also
be employed for the purpose of holding the carrier, but whatever the
form or contrivance of the holder or regulator may be, it is an oscillating
holder or regulator in combination with a carrier for the scull, fan, or
other device, arranged to cross the axis of the crank shaft by which it is
carried.
In the present example the application of the improvement to the
working of scull propellers is arranged in three different forms,-
In the first the blade is mounted in a carrier crossing the axis of the
driving shaft by which it is carried at about forty-five degrees; and in
one plan the carrier has guide arms projecting from opposite sides and
resting on horizontal ways whereon they oscillate while the carrier
swings with the cranks.
In another plan these guide arms are connected to a yoke which is
arranged to turn on a pivot instead of sliding in the horizontal guide
ways.
And in a third plan the guide is contrived in the manner of the outer
ring of gimbals being pivoted to a stationary support in one axis, and
having the carrier pivoted to it in an axis at right angles to its pivots,
and this is modified again by having the ring pivoted to the bed piece in
'the vertical axis, and the carrier pivoted to the ring at right angles to
said vertical axis.
In the accompanying Drawings A Figures 1 and 2 represents a pair of
crank shafts arranged in the same axis, the cranks B of which are set at
forty-five degrees or thereabout to the shafts, and being set at opposite

page_text: angles they carry between them the carrier C which is free in its
connection with the cranks, so that they may turn while it does not.
This carrier has the guide arms D projecting from opposite sides and
running forward and backward in the circular way F with friction
rollers E, so as to prevent rotation of the carrier. The propeller blade G
is fixed in a socket H in the under side of the shaft C, and has the
motion of a scull worked by hand imparted to it by the motion of the
shafts A, to one or both of which the power is applied. The shafts A
and the way F are arranged horizontally at the stern of the boat,
or it may be at the side if two propellers are used so that the blade
extends down into the water, then by the combined motions of the
carrier. C in the cranks and the horizontal arms D the scull motion
is produced, the propelling effect being delivered in reverse direction by
reverse motions of the cranks. The blade is by preference arranged in
the plane of the arms of carrier C, because in that position it propels
throughout its whole path, while there are two points in its path in
which it turns for a short space edgewise to the water when arranged in
the plane of the arms D.
This form of propeller has a large measure of advantages over the
screw and paddle wheel in always working so as not to disturb or churn
the water as much as they do, and in moving more comfortably away
from the water acted on, moreover it has a large sweep through the
water by reason of its greater radius, and will thus apply much greater
power than can be delivered by either of the other devices. It can be
shipped and unshipped much easier and it can be run much faster. Two
propellers of this kind may be used closer together in proportion to their
size than screws, being geared so that they swing simultaneously in the
same directions, and thus keep clear of each other. They may also be
arranged one before the other, and be coupled together so that one will
be worked by the other.
It will be seen that the essential features of the Invention are a
carrier for the blade crossing the axis of rotation of its shaft, and an
oscillating guide connected with the carrier.
In the second plan the arms D of the carrier are pivoted in a yoke
which is itself pivoted in a stationary arch-shaped upright support,
being a different arrangement of the apparatus, but having the same
effect,

page_text: In the third arrangement the arms D of the carrier are pivoted in the
axis of the blade to a ring which is pivoted at right angles thereto in the
bed frame; and in a modification of this form the arms D are pivoted
to the ring at right angles to the axis of the blade, and the ring is
pivoted to the support in the axis of the blade when it stands on the
centre.