Ar IMPROVED PROPELLER
Year: 1853

page_text: with the application for Letters Patent was not given within the
time prescribed by the Act.)
PROVISIONAL SPECIFICATION left by David Goldthorp at the
Office of the Commissioners of Patents, with his Petition, on the
19th December 1853.
I, DAVID GOLDTHORP, of Cleckheaton, near Leeds, in the County of
York, do hereby declare the nature of the said Invention for "Ar
IMPROVED PROPELLER" to be as follows:-
This Invention consists in the use and employment of certain new
mechanical arrangements and combinations of parts constituting an
improved propeller, the peculiar features of which consist in imparting
to such said propeller a "sculling" motion or movement, somewhat
similar to that commonly practised by boatmen for propelling small
boats, by imparting simultaneous vibratory and alternate circular motion
by hand to a scull placed at the stern of the boat. And the object and
intention of this Invention is to produce by mechanism a similar move-

page_text: ment to that produced by hand, as above stated, and this may be effected
by the following means:-The propeller consists of a piece of metal of
somewhat similar shape to the blade of an oar, the upper and lower
ends whereof are formed with spindles for connecting it to a frame for
supporting it, and to certain other parts employed for imparting motion
thereto, as follows:-A bracket or casting is securely fixed to the sides
of the boat or ship to be propelled, and said bracket is constructed with
bearings for supporting a shaft, which receives vibratory motion from a
crank fixed thereon and connected to any suitable prime mover. The
before-mentioned shaft has a semi-cylindrical shaped hole formed across
the same to receive the lower portion of a piece of metal, formed in the
shape of a double threaded screw, which is connected to the said shaft
by a strap screwed thereto; the upper portion of such said double
threaded piece being supported by a suitable framing for maintaining
the same in a line with the axis of the propeller, which is connected to
the double threaded screw piece by gibs and keys or in any other con-
venient manner. The feathering or turning edgewise of the propeller
simultaneously with the vibratory movement thereof is effected by
placing a nut upon the before-mentioned double threaded screw piece,
and imparting vertical movement to such said rod by means of cranks
and levers connected to the extreme ends of the nut, which is prevented
from turning round by the ends of the nut passing through and work-
ing up and down slots in the side framings which support the upper end
of the double threaded screw piece. And to reverse the direction of
motion of the propeller and boat, without stopping the machinery for
that purpose, and for turning or feathering the propeller, the same may
be effected by connecting one end of the aforesaid nut with a grooved
cam, which is held in a fixed position during the general working of
the propeller. And, firstly, to effect the feathering or turning edgewisc
thereof, the same may be performed by an arm coming into contact,
as the propeller vibrates, with stops suitably placed on the before-
mentioned cam; and, secondly, the reversing motion is effected by
unfixing the cam which was before held fast, and by lifting it up and
again fixing it in that position so as to cause the nut to act upon the
double threaded screw in an opposite direction.

page_text: It is to be understood that as the peculiar feature of novelty in this
Invention consists in imparting alternate circular motion to the pro-
peller, simultaneously with the vibratory movement thereof, any modi-
fication of the before-mentioned mechanical arrangement may be
employed for effecting such said movements.