IMPROVEMENTS IN INTERMEDIATE DRIVING GEAR FOR PADDLE WHEELS
Year: 1885

page_text: I, JOHN DEAN, of 32 High Street, London Road, Derby in the County of Derby,
Weaver do hereby declare the nature of my said invention for "IMPROVEMENTS IN
INTERMEDIATE DRIVING GEAR FOR PADDLE WHEELS" to be as follows:-
In the propelling of steam vessels, a large amount of vibration is caused through
the continually varying direction of the crank upon the paddle (or propeller) shaft,
the strain of the engine being alternately in unison with and contrary to the
vibrations caused by the paddles.
Now my invention is designed to avoid this evil, and consists in coupling the
engine shaft below to the paddle shaft vertically above it by means of preferably
two toothed wheels on the engine shaft, of less diameter than the throw of the
crank, working into larger gearing on the paddle shaft, preferably of double the
diameter of the gearing on the engine shaft. I found also in my experiments that
if the crank be of equal or of less diameter than the toothed wheel on the engine
shaft, the leverage on the latter being greater than that of the crank causes a
backward strain in the shaft at certain portions of the stroke, so that if the
bearings be loose they reciprocate to and fro, consequently I prefer to make the
crank about double the radius of the engine shaft gear wheels. By this means, and
the driving shaft being perpendicularly below the paddle shaft, I eliminate the
tendency of paddle wheel shafts to a to-and-fro movement in its bearings with
corresponding wear and tear, which is so noticeable in direct acting paddle shafts.
Similarly if the toothed wheel on the paddle shaft be not larger than the other
toothed wheel, a larger amount of vibration ensues. This gearing too has the
additional advantage of increasing the power at the expense of speed, so that
smaller and quicker engines can be employed, while the strain of the engine and
paddles being distributed over two shafts instead of one, there is less danger of
fracture. The shaft too that has the most varying strain (the crank shaft) can be
short instead of extending the whole length of the paddle shaft, so that even if it
does break it can be far easier replaced than the paddle shaft can, and a fracture of
it is not so dangerous to the skin of the ship as that of a paddle shaft would be.
While too if the engine and paddle shafts be one, the strains on the bearing are a
nearly constant backward pressure of the propelling mechanism coupled with the
incessantly varying pressure of the crank alternately backward and forward. The
strain on the paddle shaft by my arrangement is a constant forward strain from
the toothed wheel, and nearly equal and constant backward strain from the paddles,
consequently there is the minimum amount of vibration.
WP. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, and
323, High Holborn, London,
Patent Agents for the Applicant.

page_text: Improvements in Intermediate Driving Gear for Paddle Wheels.
I, JOHN DEAN of 32, High Street, London Road, Derby in the County of Derby,
Weaver, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement:-
In the propelling of steam vessels a large amount of vibration is caused through
the continually varying direction of the crank upon the paddle (or propeller) shaft,
the strain of the engine being alternately in unison with and contrary to the
vibrations caused by the paddles.
Now my invention is designed to avoid this evil and is illustrated by the
accompanying drawing which is a longitudinal section in a steamer showing
intermediate driving gear applied to a paddle wheel.
The invention consists in coupling the engine shaft A below to the paddle
shaft B vertically above it, by means of preferably two toothed wheels on the
engine shaft A of less diameter than the throw of the crank D working into larger
gearing E on the paddle shaft B, preferably of double the diameter of the gearing C
on the engine shaft. I found also in my experiments that if the crank be of equal
or of less diameter than the toothed wheel C on the engine shaft, the leverage on
the latter being greater than that of the crank causes a backward strain in the
shaft at certain portions of the stroke, so that if the bearings be loose they
reciprocate to and fro, consequently, I prefer to make the crank D about double the
radius of the engine shaft gear wheels C. By this means and the driving shaft A
being perpendicularly below the paddle shaft B, I eliminate the tendency of paddle
wheel shafts to a to and fro movement in its bearing with corresponding wear and
tear which is so noticeable in direct acting paddle shafts. Similarly if the toothed
wheels E on the paddle shaft be not larger than the other toothed wheel C a larger
amount of vibration ensues. This gearing too has the additional advantage of
.increasing the power, so that smaller and quicker engines can be employed while
the strain of the engine and paddles being distributed over two shafts instead of
one, there is less danger of fracture. The shaft too, that has the most varying
strain (the crank shaft A) can be short instead of extending the whole length of
the paddle shaft, so that even if it does break, it can be far easier replaced than the
paddle shaft can, and a fracture of it is not so dangerous to the skin of the ship as
that of a paddle shaft would be While, too if the engine and paddle shafts be
one, the strains on the bearing are a nearly constant backward pressure of the
propelling mechanism coupled with the incessantly varying pressure of the crank
alternately backward and forward. The strain on the paddle shaft by my
arrangement is a constant forward strain from the toothed wheel and nearly equal
and constant backward strain from the paddles, consequently there is the minimum
apiount of vibration.

page_text: Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1st. The improvements in intermediate driving gear for paddle wheels consisting
of an engine crank shaft immediately below the paddle shaft, but geared to and
driving this latter shaft, substantially as and for the purpose described.
2nd. The combination of the engine shaft A with its crank D and pinion
wheels C, smaller in diameter than the double throw of the crank, in combination
with the paddle shaft B having spur wheels E gearing into C and of larger
diameter than C, substantially as and for the purpose described.