Improvements in Velocipedes.
Year: 1896

page_text: Date of Application, 8th Sept., 1896-Accepted, 7th Nov., 1896
COMPLETE SPECIFICATION.
Improvements in Velocipedes.
1, CHARLES S. MOINTIRE, a citizen of the United States, residing at
67, Fidelity Building, Fourth Avenue Pittsburgh, in the County of Allegheny.
and State of Pennsylvania, U.S.A., Mechanic 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 accompanying drawings which make part of this specification, Fig. 1,
ie a side elevation of my improvement applied to a bicycle with the rear wheel
omitted and the closing side plate of the chain case removed. Fig. 2, is a
plan of the same with the rear wheel in section. Fig. 3, is a detail of the
removable side plate of the case and Fig. 4, a side elevation of the rear of
the case.
My improvements generally stated relate to a compound driving gear for
velocipedes wherein power is transmitted from the pedal shaft to the axle of the
driving wheel primarily by a compact sprocket mechanism and secondarily by
connecting rods connected to the sprocket mechanism and to the axle of the driving
wheel by cranks.
My invention further consists generally stated in the combination of the above
mechanism with the case which incloses the sprocket mechanism protecting the
same from dust, injury and contact with the garments of the rider, and also
materially stiffening the frame, which is a feature of great importance when
parallel driving rods are employed.
It is well known that various styles of driving gear have been invented to span
the distance between the pedal shaft and the axle of the driving wheel. From all
the mechanism proposed, the trade has almost universally adopted the sprocket
wheels and chain, not because it is satisfactory but the least objectionable. The
ordinary length of this chain is fifty-two inches and among other defects may be
enumerated its tendency to stretch, to bind against the points of the sprocket teeth
and to slip. It also presents a large number of pockets well adapted to receive
dust, oil and mud and the same fact is true of the sprocket wheel. Every wheelman
knows the injury caused in this way by cutting the teeth of the wheel. There is
always also some backlash.
The attempt to substitute gears for the cbain has not thus far been altogether
satisfactory and apparently never will be owing to inherent difficulties, which will
ever be present. One of these difficulties is backlash since there are from three to
nine gear wheels used and there must be sufficient space between each pair to permit
the teeth to enter and clear themselves.
Another serious question in the ordinary cogged gear driven machine is that of
alignment, for if the frame is warped or twisted the teeth will obviously not mesh,
and further also it is neither mechanically nor practically feasible to use ball
bearings on the usual train of gear wheels. The conditions therefore seem to
require some form of chain despite its disadvantages.
In the construction set forth in this specification, I use it is true a chain, but its
length is only one fourth that of the ordinary chain, as it only covers a portion of
the distance between the pedal shaft and the axle of the driving wheel, and for
this reason its stretch is reduced to one fourth. The chain also is protected from
dirt and mud and the sprocket wheels are set so close together that slipping is
practically overcome.

page_text: The chain portion of the driving gear covers only preferably about one fifth of
the distance between the pedal shaft and driving wheel axle. The remaining four
fifths is covered by rigid connecting rods, as will be more clearly seen in the
detailed description. The result is that the chain is so short that the whole driving
gear is practically a rigid one and possesses all the desirable features of such a
connection.
In the several views, 2, is the sprocket case of any appropriate form which is
preferably filled with lubricant and which is rigidly brazed and socketed to the
bottom tube, upright tube and bottom stays 3, 3, by means of the nipples 4, 5,
and 6, 6.
The case is best made in one piece except that one or the other of the sides
shall be removable plate as shown at 7, to get access to the interior of the case as
required. The gear case is provided with a sunken flange 8 to receive the side
plate flush which can be retained by a single bolt at 9 or in any suitable way.
The use of this case effectually keeps the chain and sprocket wheels from gathering
dust or mud and makes unnecessary all chain guards while affording a means for
keeping the chain constantly lubricated. Furthermore the frame is so stiffened by
the presence of this case that there is very little opportunity for distortion or
twisting.
It will be seen that my gear case can be used with practically the same
style of frame as now used on the most improved bicycles, without shortening
the frame and yet having the crank axles at the standard elevation from the
ground.
In other forms of gear support with which I am familiar the gear brackets
have been hung beneath the frame and attached thereto by bolts and nuts.
This requires the frame to be shortened approximately four inches to secure
the standard elevation for the crank axles. In the case of a ladies frame this
would raise the hem of the dress the same distance and is a positive disadvantage.
Another fault of this method of hanging the bracket below the frame is that the
power is applied some distance below the brace or triangle of the frame and has a
strong leverage to rack the frame and twist it or to loosen the bracket. My gear
case is attached right in the body of the frame and substantially at the junction of
the braces.
10, is the pedal shaft driven by cranks 11, 11 and turning in openings 12, 12¹ in
the removable side plate and in the side wall of the case the openings in said plate
and wall being large enough to receive ball bearings.
13, is a sprocket wheel keyed on the pedal shaft 10 and preferably only three
inches in diameter.
14, is a second sprocket wheel preferably one and three eighths inches in
diameter, about three inches behind the pedal shaft and on a counter shaft 15 and
baving ball bearings in the openings 16, 16' in the side plate and side wall of the
case. 17, is a suitable sprocket chain connecting the two wheels, upon the ends of
the counter shaft 15, which ends project through the case and having two
cranks 18, 18, connected to parallel rods 19, 19, which at their rear ends are
provided with cranks 20, 20, upon axle 21 of rear wheel 22. Each member of the
two pairs of cranks is best set at an angle of 90° to its mate.
It will also be seen that when the pedal shaft is at the point where the rider can
use the least muscular power, the crank on the counter shaft, 15, is at its position
for exerting the most power mechanically.
No dead centers are possible for it is only once in nine revolutions that the angle
of the pedal cranks is the same as the angle with one of the cranks 18, 18, on the
counter shaft and then only with one, never with two simultaneously.
The proportions of the machine above given may be varied but I believe only to
disadvantage. One important fact is that the only external and unprotected gear
is simple mechanism affording little lodgment for dirt, mud or oil.
Where no case is desired the shafts 10 and 15 may be supported by the frame.

page_text: Having described my invention, 1 claim,
(1.) In velocipedes, the combination of a pedal shaft, a sprocket wheel upon the
same; a countershaft immediately in the rear of said pedal shaft; a reduced
sprocket wheel upon the same; a chain connecting the two sprocket wheels; cranks
upon the ends of the counter shaft; cranks upon the axle of the driving wheel
and connecting rods joining the pairs of cranks.
(2.) In velocipedes, a compound gear between the pedal shaft and the axle of the
driving wheel, the forward and shorter member of the gear consisting of sprocket
mechanism and the rear and longer member of the gear consisting of connecting
rods and cranks.
(3.) In velocipedes, a compound gear between the pedal shaft and the axle of
the driving wheel, the forward and shorter member of the gear consisting
of sprocket mechanism, the rear and longer member of the gear consisting of
connecting rods and cranks and a case rigidly connected with the frame and
inclosing the sprocket mechanism.
(4.) In velocipedes, a compound gear between the pedal shaft and the axle of the
driving wheel, the forward and shorter member of the gear consisting of sprocket
mechanism, the rear and longer member of the gear consisting of connecting rods
and cranks and a case rigidly connected with the frame and inclosing the sprocket
mechanism, said case being provided with a removable side plate.
(5.) In velocipedes, the combination of a frame; a case secured to the lower
ends of the bottom tube and upright tube; a pedal shaft journalled in the forward
end of said case substantially at the point of intersection of the prolongation of the
bottom and upright tubes; a sprocket wheel upon said pedal shaft; a counter
shaft journalled in said case immediately in the rear of the pedal shaft; a reduced
sprocket wheel upon said counter shaft; a chain connecting the two sprocket
wheels; cranks upon the ends of the counter shaft; a rear driving wheel; cranks
upon the axle of said driving wheel and parallel driving rods connecting the pairs
of cranks.