Improvements in Bicycle Gearing.
Year: 1899

page_text: Date of Application, 10th Jan., 1899 - Accepted, 29th Apr., 1899
COMPLETE SPECIFICATION.
Improvements in Bicycle Gearing.
We, WILLIAM BOWERS, residing at No. 108, West 134th Street, in the Borough
of Manhattan, in the City and State of New York, Machinist, and GUSTAVB
SYLVAN DORWIN, residing at No. 119 West 75th Street, in the Borough of
Manhattan, aforesaid, Lawyer, 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:
-
The bearing devices for the crank rod may be applied to the high wheel
bicycle, in which the saddle is nearly over the cranks, but we will describe it
as applied to the safety bicycle.
We communicate the rotary motion from the pedal to the rear wheel by the
aid of two cranks rotated by the pedal and of two sub-cranks set nearly but not
exactly opposite, connected by parallel rods with two corresponding cranks
operating an internal gear wheel and communicating a quicker motion to an
enclosed spur gear wheel on the wheel hub. The proportions may be varied
within wide limits.
The accompanying drawings form a part of this specification and represent
what we consider the best means of carrying out the invention.
Figure 1 is a general side elevation.
Figure 2 is a side elevation of a portion on a larger scale. Certain portions
are broken away to show the interior.
Figures 3 and 4 are parts of a horizontal section, Fig. 3 showing the portion
adjacent to the crank axis, and Fig. 4 showing the parts further rearward adja-
cent to the hub of the rear wheel.
Figure 5 is a vertical section of a portion with the holding nut removed.
Figure 1 is a diagram showing the relation of certain centers on a larger
scale.
Similar letters of reference indicate corresponding parts in all the figures
where they appear.
A refers to the framing of a safety bidycle, and B the rear wheel thereof.
The front wheel C and its adjuncts may be in all respects as usual. The novelty
lies in the crank-shaft and its immediate adjuncts, the rear wheel hub and its
adjuncts, and the connections between them.
In the proper place for the crank-shaft we mount a horizontal cylindrical
revolving casing, formed in two separate or twin parts, D, D, set in line and
rigidly connected so as to revolve alike. The two serving as one, are revolved
by the cranks in the same manner as the ordinary crank-shaft. The framing is
peculiarly adapted for this construction, being made with a deep vertical plate
or web A', extending forward and backward in the center line, and having a
hole in its center, and a re-enforce around the hole which is extended to the
right and left so as to form a substantial horizontal transverse tube. A is such
short tube extending horizontally across the machine and strongly supported.
It may be drop-forged or otherwise formed integrally with the web.
The outer ends or heads of the twin cylinder D, D, are connected by the aid

page_text: of a stout rod D', formed integrally with one head, the left head D2, which rod
extends nearly the whole length of the interior of the duplex or twin cylinder.
It is widened and flattened near its end, as indicated by D³, (see Fig. 3) but has
beyond the flat portion a screw-threaded part which receives a nut E. The
opposite or right head D', is formed with a deep internal boss D³, which receives
the screw-threaded end of the rod D', and also the securing nut E. This boss
is continued inward by two stout projections D, D, having flat inner faces
presented towards each other, (see Fig. 5).
Each crank Do, in addition to its usual functions of carrying a pedal F, is
formed with a lateral arm having a nicely finished cylindrical bearing Ds, serving
as a sub-crank, which engages a parallel or side rod G, analogous in its functions
to the part similarly designated in a locomotive, which communicates the rotary
motion of the sub-crank D8, to a corresponding crank further rearward, as will
presently appear.
The sub-cranks 18 are arms formed integrally with and projecting laterally
from, the inner ends of the corresponding cranks D. beyond the portion which
receives the side rod G and gives motion thereto, is a flat portion D, which
engages in a closely fitting corresponding hole in the root or stub 17, formed
integrally with the adjacent part of the twin cylinder D. The extreme end of
the lateral arm D8, D is screw-threaded and receives a nut D".
The rods G G work at the sides of the machine respectively with nearly oppc
site motions. Each is operated by one of the sub-cranks D³, and acts at its rear
end on a crank M', carried on a larger internal gear-wheel M, which is mounted
in ball bearings in a fixed casing A3 having a back A. This is arranged eccen-
trically to the axis of the rear wheel, and its center revolves around the same,
and its nicely cut gear teeth engage with correspondingly cut spur gear teeth
on the smaller pinion B' firmly set on the hub of the rear wheel B. A stationary
shaft extends through the hub of the rear wheel and carries the bearings for
said wheel. A bracket B2 secured to the back A, of each casing, projects later-
ally and supports the contiguous end of said stationary shaft.
It will be noted that each crank pin M' is firmly carried by a disc M³, pro-
vided with an internal flange or inner annular offset M³, externally threaded
and extending for a short distance within the opening in the front of the fixed
casing A, as shown most clearly in Fig. 4. Engaging the threads of the off-
set M³, is the internally geared wheel M, the engagement being secured by a
small lock-screw M4, let in through the front of the disc M2, and biting the
threads of the wheel M at one point.
Each gear-wheel M, has two sets of ball bearings M5, M6, to provide for which
ball races are presented by an inner bearing section A5, annular ring M18, having
double bearing faces, and an outer bearing section A6, in threaded engagement
with the outer portion of the case A3, to permit its ready removal and application.
The bearing ring M8 is also a separable part in threaded engagement with a
central series of threads on the wheel M, so that it can be laterally shifted
thereon, to secure nice adjustment of the internally geared wheel, and also take
up wear of parts.
The disc M², whilst providing for the support of one of the cranks M¹, and for
operating its gear wheel M, also serves as the face plate for its casing A³, and
has a marginal portion M10, extending beyond the opening in such casing, to
constitute a guard for the exclusion of dust while admitting of the free revolution
of the parts.
Bicycles are used largely for recreative purposes, and the appearance which a
machine presents in motion is important. If the parallel rods G connect cranks
which are set in the ordinary manner, nearly quartering to each other, the
effect on the eye, seeing both rods move forward and then both rods move back-
ward together is disagreeable. We have discovered that the cranks connected
to the parallel rods, may be set so nearly opposite as to produce an agreeable
effect on the eye by the synchronous motion in opposite directions, so as to pro-

page_text: duce a pleasing effect, while the cranks, being a little out of opposition, will
avoid dead-points.
The pedals F, F, are mounted in the usual manner on cranks set exactly
opposite each to the other, so that as one moves upward the other moves down-
ward, and as one moves forward the other moves backward. The sub-cranks Ds,
are nearly but not exactly in the same relation; their positions differ about 150
from being exactly opposite. The corresponding cranks M' on the internally
geared wheel M connected through the gearing are correspondingly set. It
follows from this arrangement that while the slide rods present the generally
symmetrical action of one going forward while the other moves backward, their
motions differ sufficiently therefrom to avoid the dead-points. The angle may
be varied. In theory the most effective position would be what is in shop-
language termed quartering", the sub-cranks standing at an angle of 90°
each from the other. But we prefer about fifteen degrees, because it allows the
end to be attained without seriously interfering with the symmetry of the action.
We attach importance to the two sets of ball bearings for each wheel, because
they not only perform the ordinary functions of reducing friction but also as
arranged, hold the large wheel truly in its plane, and prevent all lateral motion.
They allow the casing to be dust-tight.
6.
Further modifications may be made. We have shown liberal oil holes in the
horizontal transverse tube A², occurring in the plane of section; they may be
placed in other positions. Some or all may be dispensed with, if preferred.
There should be an oil hole in the web A', but its preferable position being on
the upper side, it is out of the plane of section and cannot well be represented.
There should obviously be the ordinary provisions for oiling at other points.
Ball bearings are provided as shown, to support the twin cylinder D, and on
the transverse tube A2, as well as in the usual positions on the structure, the
hub-bearings, pedals, etc.
The breadth of the cylindrical portion of each lateral arm or sub-crank D8,
where it receives the side rod G, is a little greater than the breadth of the side
rod, so that the rod is relieved from lateral pressure. The construction allows
ample room for these parts without extending the cranks objectionably outward,
and allows the twin cylinder to be supported by ball bearings at its extreme
ends.
We have in Fig. 1, shown the sub-cranks more nearly in a straight line than
the 15° above defined, and in Fig. 1, have shown the divergence exaggerated,
more than fifteen degrees out of line. This may be considered to indicate approxi-
mately the extreme of the range allowable.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. As an improvement in driving gear for bicycles, the cross tube A2, rigidly
supported on the frame, a case D in two parts revolving on the exterior thereof
and having the cranks attached, and the rod D¹ extending axially through the
tube and uniting the two parts of the casing, substantially as herein specified.
2. As an improvement in driving gear for bicycles, the cross tube A2 rigidly
supported on the frame, the case or twin cylinder D revolving on the exterior
thereof, and having the cranks attached, and the rod D¹ extending axially
through the tube, the case being in two distinct parts, the rod fixed rigidly to
one part and locked against revolving relatively to the other part by the pro-
jections D on one part embracing a corresponding portion D³, on the other part,
all arranged for joint operation substantially as herein specified.
3. In a bicycle, the driving wheel having a pinion on the hub thereof, an in-
ternal gear meshing with said minion, a stationary shaft extending through said
hub and carrying the bearings for the said wheel, a frame having a casing
which surrounds said pinion, a bracket which supports the end of said stationary

page_text: shaft within said gear, in combination with each other and with a corresponding
set of such driving mechanism, enclosing casing and bracket on the opposite
side, the mechanism arranged to act at alternate intervals, all substantially as
herein specified.
4. In a bicycle, the driving wheel having a pinion on the hub thereof, an
internal gear meshing with said pinion, and a stationary shaft extending through
said hub and carrying the bearings for the said wheel, a frame having a casing
which surrounds said pinion and said internal gear and forms a bearing for said
internal gear in the plane of said pinion, a bracket which supports the end of
said stationary shaft within said internal gear, a driving rod connected by
a crank pin with said internal gear, and means for imparting rotation to said
internal gear through said driving rod, in combination with each other and
with a corresponding set of such driving mechanism, enclosing casing and
bracket on the opposite side, the mechanism arranged to act at alternate inter-
vals, all substantially as herein specified.
5. In a bicycle, the frame, an internal gear having an adjustable projecting
ring on the outside of said gear, a driving rod connected by a crank pin with
saich gear, and means for imparting rotation to said gear through said
driving rod, a ball bearing composed of two sets of balls between a portion of
said frame and the said gear bearing against opposite sides of said ring and
provided with an independently adjustable ring A, the adjustment of the latter
and of said projecting ring on said internal gear serving to adjust the bearing
of both sets of balls without changing the plane of movement of said driving rod,
in combination with each other and with a corresponding set of such driving
mechanism, enclosing casing and bracket on the opposite side, the mechanism
arranged to act at alternate intervals, all substantially as herein specified.
6. In a bicycle, the driving wheel having a pinion on the hub thereof, an
internal gear meshing with the said pinion, the stationary shaft extending
through said hub and carrying the bearings for the said wheel, a frame having
a casing which surrounds said pinion and said internal gear and forms a bearing
for said internal gear in the plane of said pinion and which has a back A' and a
bracket B2 carried by said back plate within said internal gear, the end of said
stationary shaft being supported by the said bracket, in combination with each
other and with a corresponding set of such driving mechanism, enclosing casing
and bracket on the opposite side, the mechanism arranged to act at alternate
intervals, all substantially as herein specified.
บ
1000
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.