IMPROVEMENTS IN MEANS FOR SPEED GEARING MARINE PROPELLER ENGINES to be as follows
Year: 1884

page_text: We JOHN ROWAN and ROBERT ROWAN Engineers, and MARY ROWAN, Spinster
all of Belfast in the County of Antrim Ireland the Executors of WILLIAM ROWAN
of Belfast aforesaid, Engineer deceased do hereby declare the nature of said
invention for "IMPROVEMENTS IN MEANS FOR SPEED GEARING MARINE PROPELLER
ENGINES to be as follows :—
"
The object of this invention is to increase the efficiency of marine engines and
screw propellers, to economize fuel and to prevent accidents to the propeller
shafting and engines by lessening the friction and slip or waste of power, now
occurring with screw propellers and by producing a softer and more uniform
motion of same. The aforesaid defects arise mainly from the extreme coarseness
of the pitch which is rendered necessary by reason of the comparatively slow
speed of revolution at which it is possible to drive the engines, the limit of
shortness of stroke and of piston speed having been already practically attained.
According to this invention the screw propeller is constructed with a fine pitch
for instance say one half or one fourth of the usual pitch and the number of its
revolutions is increased proportionately while the engines are allowed to run at
their present or normal or slower speed. For this purpose the power of the engine
is communicated to a countershaft which runs in bearings in frames or framing
erected on or formed in one with a substantial bed plate, the said bearings being
capable of being set up or adjusted by means of regulating screws as to the
distance of the centres of the countershaft from the centres of the engine
shaft and of the propeller shaft so as to ensure the minimum tension in the
driving ropes compatible with a transmission of power without slip. The engine
shaft and the propeller shaft are by preference arranged linable with each
other or nearly so in a vertical plane though separate from each other but having
their end bearings on the same aforesaid bed plate or within the same framing.
The end bearing of the propeller shaft (being its forward end bearing) is a
thrust bearing of any suitable form, but the end bearing of the engine shaft
(being its aft bearing) is an ordinary bearing, the end thrust now usually
coming on the engine is thus quite done away with. On the engine shaft
Dains C71

page_text: within the said framing is fixed a driving pulley with a series of V grooves and on
the countershaft a corresponding but smaller V grooved pulley for communicating
the motion from the engine shaft to the countershaft by a number of comparatively
small and hence flexible wire or other ropes to produce a soft and noiseless but
powerful transmission. On the countershaft and within the framing is also fixed
a larger V grooved pulley and on the propeller shaft a corresponding but smaller
V grooved pulley for communicating the motion by wire or other ropes similarly
to the propeller shaft, which latter will thus run at a much quicker speed of
revolution than the engine shaft.

page_text: COMILEID
DIECIFICATION,
We JOHN ROWAN and ROBERT ROWAN Engineers and MARY ROWAN, Spinster,
all of Belfast in the County of Antrim, Ireland, the Executors of WILLIAM ROWAN
of Belfast aforesaid, Engineer deceased do hereby declare the nature of said
invention for "IMPROVEMENTS IN MEANS FOR SPEED GEARING MARINE PROPELLER
ENGINES"
and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
The object of this invention is to increase the efficiency of marine engines and
screw propellers, to economise fuel, and to prevent accidents to the propeller,
shafting and engines by lessening the friction and slip or waste of power now
occurring with screw propellers and by producing a softer and more uniform
motion of same. The aforesaid defects arise mainly from the extreme coarseness
of the pitch which is rendered necessary by reason of the comparatively slow speed
of revolution at which it is possible to drive the engines the limit of shortness of
stroke and of piston speed having been already practically attained.
Figure 1 of the accompanying drawings is a part sectional side elevation showing
the invention as applied in connection with a screw propeller shaft, and Figure 2
is an end view.
According to this invention the screw propeller A is constructed with a fine
pitch for instance say one half or one fourth of the usual pitch and the number of
its revolutions is increased proportionately while the engines are allowed to run
at their present or normal or slower speed. For this purpose the power of the
engine is communicated from the engine shaft B to a countershaft C which runs in
bearings F in frames D or framing erected on or formed in one with a substantial
bed plate E the said bearings F being capable of being set up or adjusted by means
of regulating screws G as to the distance of the centres of the countershaft C from
the centres of the engine shaft B and of the propeller shaft H so as to ensure the
minimum tension in the driving ropes I and K compatible with a transmission of
power without slip. The engine shaft B and the propeller shaft H are by pre-
ference arranged lineable with each other or nearly so in a vertical plane as shown
here though separate from each other but having their end bearings L and M
respectively on the same aforesaid bed plate or within the same framing. The end
bearing M of the propeller shaft H (being its forward end bearing) is a thrust
bearing of any suitable form but the end bearing L of the engine shaft B (being its
aft bearing) is an ordinary bearing; the end thrust now usually coming on the
engine is thus quite done away with. On the engine shaft B within the said
framing is fixed a driving pulley N with a series of V grooves and on the counter-
shaft Ca corresponding but smaller V grooved pulley O for communicating the
motion from the engine shaft to the countershaft by a number of comparatively
small and hence flexible wire, cotton, flax, hemp or other ropes I to produce a
soft and noiseless but powerful transmission. On the countershaft C and within
the framing is also fixed a larger V grooved pulley P and on the propeller shaft H
a corresponding but smaller V grooved pulley Q for communicating the motion by

page_text: wire or other ropes similarly to the propeller shaft H which latter will thus run at
a much quicker speed of revolution than the engine shaft.
Having now particularly described and ascertained the nature of said inven-
tion and in what manner the same is to be performed we declare that what
we claim is
•
First: The mode of transferring the motion of the engine shaft to the propeller
shaft through the intervention of a countershaft which works in adjustable
bearings, and of a number of endless wire or other ropes working on pulleys
provided with a corresponding number of grooves, substantially as and for the
purposes set forth.
Second: The construction and arrangement of parts shown on the drawings.