Improvements in Bicycles.
Year: 1891

page_text: Date of Application, 31st Mar., 1891-Accepted, 13th June, 1891
COMPLETE SPECIFICATION.
Improvements in Bicycles.
I, JOHN BENJAMIN EVANS, a citizen of the United States, residing at
No. 28 Wyoming Street, Philadelphia, Philadelphia County, in the State of
Pennsylvania, United States of America, 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 :-
My invention is of especial applicability to the class of bicycles which are
known as Safeties, and in which the propulsion of pedals is transmitted to the rear
wheel as a driver through the intervention of sprocket chains or kindred gearing.
Under modifications which would be apparent to a bicycle builder the invention
is also applicable to other types of machines.
My invention aims to provide a gear connection between the crank axle and
the driving wheel by which the rotation imparted to the crank axle may be at
will applied to either speed or power.
A further object is the provision of a
gearing of this character which is so mounted and arranged that not only the
running of said connecting gear but also the shifting of the set of said gear from
speed to power or from power to speed is accompanied by the minimum of friction.
In the drawings I show and herein I describe a preferred form of a convenient
embodiment of my invention, the particular subject-matter claimed as novel being
hereinafter definitely specified.
In the drawings,
Figure 1 is a view in side elevation of a bicycle embodying my invention.
Figure 2 is a central longitudinal vertical sectional elevation through the crank
axle, its casing, and associated parts.
Figure 3 is a vertical transverse sectional elevation taken on the line x-x of
Figure 2.
Figure 4 is a transverse vertical sectional elevation taken on the line
Figure 2.
y
"
of
Figure 5 is a transverse vertical sectional elevation taken on the line - of
Figure 2.
Similar letters of reference indicate corresponding parts.
In the drawings,
A represents the main frame of the machine, which may be of any preferred
construction usual in bicycles. B is the front or pilot wheel; C the front fork
and fork standard of said wheel; D the steering handle; E the rear or driving
wheel, and F the saddle support upon the main frame.
All of the foregoing parts are usual in machines of the class represented.
G is the crank axle, and g¹ g² a pair of sprocket wheels mounted so as to run
freely upon the respective extremities of said axle,- being a minor, and g² a
major, sprocket wheel.
H H are a pair of driving pedals respectively applied to the respective
extremities of the crank axle outside of the sprocket wheels.
The axle of the driving wheel is equipped with a pair of sprocket wheels i,
which are by means of chains in gear with the wheels g¹ g² respectively.
J is a cylindrical casing which contains and supports the crank axle and its
connected parts, and which is in turn connected with the main frame of the bicycle
in any convenient manner, as, for instance, by the depending hanger a, from the
lower end of which projects a stud a* clasped by a pair of arms; rising from the
casing and secured together above said stud by a thumb screw jx.
Each of the sprocket wheels g¹ g embodies in its hub, a clutch face, and two
ball race grooves, and, it being desirable that the hubs should be of metal much

page_text: i
more durable than is required for the remaining portions of said wheels, I form
each wheel in two parts, an outer designated K, and comprising the rim, spokes,
and ring K, and an inner designated K2 and constituting the hub. The inner
face of each hub K2 embodies a clutch face K3 and the rim of each inner face is
recessed to form an annular groove or ball race K4, which groove being formed in
the corner portion of each hub opens through or faces both its top and side, is
hereinafter termed the rim groove, and is, so to speak, oblique or inclined.
The outer edges of the casing J overhang or enclose the inner portions of the
respective hubs, and said edges are flared or recessed as at 2 to form in each a
groove, which grooves face the respective grooves K, and are correspondingly
oppositely inclined, so that the opposing pairs of grooves form ball races in which
are situated balls K³ to form ball bearings.
The outer face of each hub embodies an annular recess, surrounding its central
aperture, opening both upon the axle and upon or through the end of said hub, so
as to form an inclined groove or ball race termed hereinafter the bore groove, the
outer openings of which recesses are closed by the collars M, circumscribing the
axle, and embodying inner faces m curved in a direction opposite to the curvature
of the inner portion of the recess, so that a ball race is formed between the
bottoms of the recess and the curved faces m of said collars, within which recesses
are placed the balls 1.
It will be understood that both ball races described, being formed by opposing
pairs of grooves placed in inclined or oblique relationship to each other, may be
adjusted as to size by causing the parts in which the respective grooves are formed
to approach or recede with reference to each other, and that therefore wear of the
balls or of the metal of the ball races may be compensated for, and, to permit
such taking up, one of the collars M is screw threaded upon the crank axle.
The exterior of the hub embodies a squared recess or seat to receive the ring K¹
of the part K of the wheel, and in said seat may be located square headed pins, n,
which cake into square recesses in the inner faces of the ring K¹ so that when the
parts are assembled the hub and body of the wheel may be rotated together. To
secure the body K of the wheel against withdrawal from the hub, screws n³ may
pass obliquely as shown through the ring K' and be slightly sunk into the metal
of the hub.
O is a clutch circumscribing the crank axle, and keyed thereto by a key o which
permits its longitudinal movement upon, but compels its rotation with, the axle.
The clutch is provided at each end with a clutch face ox, so that it may be
thrown into engagement with the clutch faces of either of the wheels g' g² at will,
and of such size that when occupying its central position it is out of engagement
with both said clutch faces.
To provide for the throw of the clutch, I form it with a central transverse
groove o¹, in which the arm of a bell-crank lever P supported at the side of the
casing in any convenient manner is constantly engaged. The bell crank lever or
other clutch throwing contrivance is conveniently operated through a system of
bell crank and link connections R, through which the movement of a hand lever Q
applied to the steering handle D are transmitted to it.
Qx is a rack depending from the handle D and embodying recesses designed to
receive and hold the lever Q, each recess being adapted to maintain it in one of
the three respective adjustments of which the said lever is capable in placing the
clutch in its respective positions of engagement with the major sprocket wheel,
of disengagement from both wheels, or of engagement with the minor sprocket
wheel.
In the practical employment of my invention, as will be understood, when the
clutch is in engagement with the minor sprocket wheel, the clutch, wheel, and axle,
carrying the ball with them, rotate together as an entirety, resting and bearing
their weight through the balls K³ upon the casing. The major wheel g² through
being geared to a sprocket wheel on the shaft of the driving axle, is driven thereby
and rotates idly upon its shaft, through the balls 1, being supported in vertical

page_text: :
position by a series of balls K³ against which its groove face K bears.
The major
wheel, therefore, is both prevented from making frictional contact with the casing
and is supported and held in vertical position by said balls K³. When the clutch
is reversed so as to set free the minor and engage with the major wheel the
operation is correspondingly reversed.
It is obvious that by forming the sprocket wheels in the manner described in
two parts, one forming the hub, and the other the body of the wheel, the same hub
may be employed in connection with a number of wheels of different size in
succession, whereby the adjustment of said wheel, in effect, becomes possible.
It is obvious that in the practical employment of my invention it is possible for
the rider to by setting the clutch in its intermediate position in which it is
withdrawn from engagement with both sprocket wheels, hold his feet upon the
pedals and maintain them relatively stationary while the machine is coasting,
for the reason that in such position both sprocket wheels will rotate idly upon the
crank axle.
It is further obvious that the arrangement shown and described, in which the
clutch in its intermediate position is out of engagement with both clutch faces of
the sprocket wheel is a feature of value inasmuch as the rider of the machine, in
changing the gear, may avoid the possibility of breakage which might be incident
to abruptly shifting the clutch when at one speed into engagement with a wheel
revolving at another speed, by withdrawing said clutch into said intermediate
position, suitably modifying, through the instrumentality of the pedals, the speed
of rotation of the axle to suit the speed of the sprocket wheel with which
engagement it is to be made, and effecting said engagement by means supplied for
the purpose.
I prefer to so arrange the clutch or the mechanism controlling it that it shall
normally be in engagement with the clutch face of the minor sprocket wheel, and
this may of course be accomplished in various ways. prefer to accomplish this
object however by the employment of a spring, which may be placed in whatever
part of the machine convenience of manufacture and use may dictate.
In the last
figure of the drawings I show a springs as applied in connection with the ball
crank lever P, the free end of which spring is to be secured to an adjacent
portion of the casing, as, for example, the portion farthest from the eye in Figure 2,
or otherwise as the constructor, in whose province the location of said spring
belongs, may prefer.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is -
:-
1. In combination with a bicycle having a driving wheel, a crank axle, driving
pedals mounted on said axle, two sprocket wheels loosely mounted on said axle,
a clutch adapted to make engagement with either of said sprocket wheels at will
but so influenced by a spring as to be normally in engagement with the smaller of
said wheels, substantially as set forth.
2. In combination with a bicycle having a driving wheel, a crank axle, driving
pedals mounted on said axle, two sprocket wheels mounted on said axle and geared
with the driving wheel, a clutch mounted upon said axle, and adapted to be set
in engagement with either of said sprocket wheels, said axle and clutch being
together mounted in a boxing, and means for shifting said clutch, substantially as
set forth:
3. In combination with a bicycle having a driving wheel, a crank axle, driving
pedals mounted upon said axle, two sprocket wheels mounted upon said axle and
geared with the driving wheel, a clutch mounted upon and keyed to the axle and
adapted for engagement with either of said sprocket wheels, an enclosing boxing
in which said axle and clutch are mounted, within which they are provided with
ball bearings, and means for occasioning the throw of the clutch, substantially as
set forth.

page_text: 4. As an article of manufacture, a composite wheel for a safety bicycle of the
character described, consisting of a hub embodying a clutch face, and a.removable
body or rim,, substantially as set forth-
5. Inca bicycle, in combination with. a-driving wheel, a crank. axle, clutch.faced
sprocket wheels mounted on said axle and geared with the driving wheel,.. the
hubs of which sprocket wheels each embody a ball-race-groove, a clutch niounted
on an axle, means for throwing the clutch, a casing encircling the clutch, and
embodying ball-race grooves which respectively face the ball-race grooves in the
hubs to form ball races, and balls mounted in said races, substantially as set
forth.
6. In a bicycle, in combination with a driving wheel, a crank axle, clutch
faced sprocket wheels mounted on said axle, the hubs of which each embody an
inclined ball race groove, which sprocket wheels are geared with the driving wheel,
a clutch mounted on said axle, means for throwing the clutch, a casing encircling
the clutch and overhanging the inner ends of the hubs of the sprocket wheels,
which casing embodies inclined ball race grooves which respectively face the
respective grooves upon the hubs to form ball races, and balls mounted in said
races, substantially as set forth.
7. In a bicycle, in combination with a driving wheel, a crank axle, a clutch
faced sprocket wheel the hub of which embodies an inclined bore groove, a collar
embodying an inclined curved face, said collar being so set that its curved face
registers with the inclined groove of the hub to form a ball race, and balls mounted
in said race, substantially as set forth.
8. In a bicycle, in combination with a driving wheel, a crank axle, clutch faced
sprocket wheels mounted on said axle and geared with the driving wheel, the
hubs of which sprocket wheels each embody an inclined rim groove and an inclined
bore groove, a clutch mounted on said axle, means for throwing the clutch, a
casing or annular framing embodying inclined ball race grooves which face the rim
grooves of the hubs to form ball races, balls in said races, collars or kindred
projections, each embodying a curved face, mounted on the crank axle and each
facing one of the bore grooves to form a ball race, and balls mounted in said races,
substantially as set forth.
9. In combination with a bicycle, a crank axle, a clutch, a pair of clutch faced
sprocket wheels, and a casing, ball races formed by inclined grooves in the casing,
and in the hubs of the wheels, ball races formed by inclined grooves in the bores
of the sprocket wheels and in collars or projections on the crank axle, and balls
in the respective ball races, substantially as set forth.
10. In combination with a bicycle, a crank axle, a clutch, a pair of clutch faced
sprocket wheels, and a casing, ball races formed by inclined grooves in the casing
and in the hubs of the wheels, ball races formed by inclined grooves in the bores
of the sprocket wheels and in collars or projections on the crank axle, balls in the
respective ball races, and means for taking up wear of the balls and in the faces
of the grooves, substantially as set forth.
11. In a bicycle, in combination, an axle, a sprocket wheel, mounted thereon,
a pair of ball races the balls of which furnish such lateral support to said wheel as
to maintain it in position, and a clutch adapted to be thrown into and out of
engagement with said wheel, substantially as set forth.
Dated this Second day of March A D 1891