Year: 1896

page_text: Date of Application, 17th Dec., 1896
Complete Specification Left, 17th Sept., 1897-Accepted, 13th Nov., 1897
I, WILLIAM MAXWELL of 123 London Road, Glasgow, Cycle Agent, do hereby
declare the nature of this invention to be as follows:-
This invention relates to cycles and it has for its object to improve the driving
mechanism thereof and also to obviate the necessity for using large and clumsy,
gear cases as at present.
In carrying out my invention the bottom bracket is made of large enough
diameter so to enclose the whole of the driving gear including the chain wheel
The gear is a multiplying one and all the increase of speed is given by it and not
by the chain wheels as usual. These latter are small and preferably both of the
same size. The chain wheel. on the crank axle is preferably arranged within the
bettom bracket just in or about the same line as the horizontal back stay. An
opening is made or left in the bottom bracket for the chain to pass through to
the chain wheel.
The chain wheels being very small and of the same size it is evident that a very
small gear case will suffice to enclose the chain. I propose to make the gear case,
under one arrangement, of two parts which respectively lock on to flanges or
clip pieces made on or secured to the upper and lower sides of the horizontal
back-stay. The parts may be locked in position by means of spring pins or such
like. The bottom bracket, whose ends are detachable so as to take out the gear,
practically constitutes one end of the gear case while the bracket at the rear end
of the frame, which is also arranged so as to enclose the rear chain wheel, con-
stitutes the other end of the gear case. This rear bracket may be closed in dust
proof in any suitable manner.
Provision is made in the rear bracket for moving the axle of the back wheel
so as to tighten up the chain from time to time.
With this form of gear case the brackets made one with the frame form the
ends, the back stay the centre and the two removable parts the top and bottom.
The gearing and the chain is locked up dust and rain proof.
The gear case need only be the matter of three or four inches wide.
The multiplying gear enclosed in the bottom bracket may be of any suitable
construction.
If desired the brake may be made to act on the gear.
Under a modification the frame may be made with two horizontal back-stays
which support the sides of the gear case between them. One only or both of these
sides may be removable. The top and bottom of the gear case is made by pieces
secured to or made one with the stays.
The gear case may be lined at top and bottom with felt or leather and if desired

page_text: vertical ribs or pieces of felt or leather may be fitted in the gear case. These
felt or leather pieces prevent the chain rubbing against the walls of the case.
The gearing used may be epicycloidal or like gear.
Dated this 16th day of December 1896.
H. D. FITZPATRICK,
70 Wellington Street, Glasgow, Agent.
I, WILLIAM MAXWELL, of 123 London Road, Glasgow, Cycle Agent, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
This invention relates to cycles and it has for its object to improve the driving
mechanism thereof and also to obviate the necessity for using large and clumsy
gear cases as at present.
And in order that my said invention may be properly understood I have here-
unto appended an explanatory sheet of drawings, whereon,
Fig. 1 shows a part of the frame of a bicycle the bottom bracket being sectioned.
The section is taken on the line Y-Y Fig. 2..
Fig. 2 is a vertical section of the bottom bracket taken on the line X, X, Fig. 1.
Fig. 3 is a section of the gear case and back stay taken on the line Z, Z Fig. 1.
On the drawings the same reference letters wherever repeated indicate the
same parts.
In carrying out my invention I make the bottom bracket a of the frame b much
larger in diameter than usual and in this bracket I arrange the multiplying gear for
driving the chain wheel g and also the chain wheel g itself. c, c, are the covers
of the box bearing and as usual they are screwed in place into the bracket. dis
the crank axle. e, e¹, are the pedal cranks. f are balls. dare grooved ball
races made on the crank axle.
The multiplying gear for driving the chain wheel may be of any suitable and well
known description but I prefer, epicycloidal gear as shown. This gear consists
of an internally toothed ring h, fitted securely in place within the bracket a,
whose teeth mesh with the teeth of two toothed pinions i, i, carried in bearing
forks on the ends of an S lever j. The collar of the S lever is keyed on the
crank axle as shown so as to revolve with it. The teeth of the pinions i, ', mesh
with the teeth of a wheel 7 made in one with a sleeve m running on, balls f on the
crank axle. Screwed on the outer end of this sleeve m is the chain wheel g. n is
a jam nut for holding the chain wheel in place on the sleeve. The axle runs in
the usual ball bearings.
As will be seen the chain wheel 9 is made much smaller than usual being in
fact preferably about the same size as the sprocket pinion o on the hub of the
driving back wheel of the machine.
P, p', are openings made in the bottom bracket for the chain g
through.
pass
The gear case is made in two parts r, r¹, preferably of a rectangular shape as
shown in section at Fig. 3. These parts fit on hollow preferably rectangular pro-
jecting lugs s, s¹, made in one with or soldered or brazed on the bottom bracket
and also on hollow, preferably rectangular, supports t, t, made one with or secured
to a sleeve or ring 2 fitted on the back stay u of the frame. The supports are
indicated in dotted lines at Fig. 1. The two halves or parts r, rl, of the gear case

page_text: are provided with small lugs which can be secured together by screws, catches
or such like. The parts r, r', of the gear case can be locked together in any other
well known and suitable manner. The back part of the case may be hinged as
shown for the purpose of facilitating the adjustment of the back wheel when
tightening up the chain.
The parts of the gear case enclose the greater part of the back stay.
If desired the bottom bracket may be made or extended so as to only partially
enclose the chain wheel.
The chain wheel being much smaller than usual it is evident that a much
smaller gear case than usual will suffice to enclose the chain. As shown on the
drawings which are made to a scale full size the gear case need only be the
matter of three or four inches wide.
If desired the two passages in the gear case may be lined at top and bottom with
felt or leather, for the purpose of preventing the chain rubbing against the walls
of the case.
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
consider novel and desire to claim is:-
1. The combination of a hollow bottom bracket or its equivalent, a chain wheel
erclosed within the bottom bracket, and gearing for driving the chain wheel
also enclosed within the bottom bracket, substantially as hereinbefore set forth.
2. The combination of a hollow bottom bracket or its equivalent, a chain wheel
enclosed within the bottom bracket, and epicycloidal gearing for driving the
chain wheel also enclosed within the bottom bracket, substantially as hereinbefore
set forth.
3. The combination of the hollow bottom bracket or its equivalent, the chain
wheel enclosed within the bottom bracket the gearing for driving the chain
wheel and the gear case for enclosing the chain all substantially as hereinbefore
described with reference to the drawings annexed.
Dated this 16th day of September 1897
H. D. FITZPATRICK,
70 Wellington Street, Glasgow, Agent.