New or Improved Means for Adjusting the Back Wheel Axle of a Safety Bicycle, applicable also to certain other Wheel Axles of other Velocipedes and Motor Vehicles..
Year: 1897

page_text: Date of Application, 21st Jan, 1897
Complete Specification Left, 21st Oct., 1897-Accepted, 21st Jan., 1898
PROVISIONAL SPECIFICATION.
New or Improved Means for Adjusting the Back Wheel Axle of a
Safety Bicycle, applicable also to certain other Wheel Axles of
other Velocipedes and Motor Vehicles..
I, ROBERT WALKER SMITH, of the Eadie Manufacturing Company Limited, of
Redditch, in the County of Worcester, Engineer, do hereby declare the nature of
this Invention to be as follows:-
--
This Invention consists of the herein described new or improved means for
adjusting the back wheel axle of a safety bicycle nearer to or farther from the
driving crank axle so as to adjust the driving chain to the proper tension or so
as to enable the driving chain to be removed from the sprocket wheel before the
said back wheel and its axle are removed from the bicycle frame. My Invention
is similarly applicable to the wheel axles of other velocipedes and motor vehicles
which are driven by an endless chain or like gearing where the said wheel axle
has to be adjusted as stated above.
I will describe my Invention as applied to the back wheel of a safety bicycle.
In carrying out my Invention the said back wheel axle is mounted eccentric-
ally in two worm wheels which are arranged to turn in recesses formed in the
back forks or brackets of the bicycle frame or are otherwise carried by the said
back forks or brackets. Gearing with each of these worm wheels there is a worm
or screw carried by a lug or other bearing formed on or fixed to the said back
bracket or part of the bicycle frame the said worm spindle having a milled nut
or being otherwise formed so that it can conveniently be turned. As before stated
the holes in the worm wheels through which the back wheel axle passes are out
of the centre of the worm wheels so that when the worm wheels are turned by the
worms in one direction the wheel axle will be moved nearer to the driving crank
axle thereby slackening the driving chain and when the worm wheels are turned
in the opposite direction the back wheel axle will be moved farther from the
crank axle thereby tightening up the driving chain. The said back brackets or
parts of the frame of the bicycle have curved slots formed in them so as to permit
of the proper movement of the back wheel axle and these slots are by preference
made open at their lower parts so that the back wheel axle can readily be removed.
Instead of the lugs or bearings which carry the worm spindles being formed with
the back brackets of the bicycle frame as above described, each of these lugs
or bearings may be formed with a sheet metal or other disc or plate which fits
in the recess in the back fork bracket behind the worm wheel, the said disc being
prevented from turning by the said lug fitting in a notch or recess in the
bracket.
Each of the said lugs or bearings for the worm spindles is by preference

page_text: (although not necessarily) arranged above the worm wheel so as to be out of the
way of the nut on the end of the back wheel axle.
Dated this 20th day of Janu 1907
CHARLES BOSWORTH KETLEY,
Agent for the Applicant.
New or Improved Means for Adjusting the Back Wheel Axle of a
Safety Bicycle, applicable also to certain other Wheel Axles of
other Velocipedes and Motor Vehicles.
I, ROBERT WALKER SMITH, of the Eadie Manufacturing Company. Limited, of
Redditch, in the County of Worcester, Engineer, 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:-
•
This Invention consists of the herein described new or improved means for
adjusting the back wheel axle of a safety bicycle nearer to or farther from the
driving crank axle so as to adjust the driving chain to the proper tension or so
as to enable the driving chain to be removed from the sprocket wheel before the
said back wheel and its axle are removed from the bicycle frame. My Invention
is similarly applicable to the wheel axles of other velocipedes and motor vehicles
which are driven by an endless chain or like gearing where the said wheel axle
has to be adjusted as stated above.
I will describe my Invention as applied to the back wheel axle of a safety bicycle
and I will refer to the accompanying drawings on which Fig. 1 is a side elevation of
the end portions of the bottom fork and brackets and back stays of a safety bicycle
shewing also the back wheel axle with my Invention applied; Fig. 2 shews the
same parts as Fig. 1 but with the wheel axle in a different position in the bracket
so as to illustrate the action of my Invention; Fig. 3 is a cross section on line XX
of Fig. 1; Fig. 4 shews the bracket part separately; Fig. 5 is a side and edge
view of one of the worm wheel parts of my Invention separately; Figs. 6, 7 and 8
illustrate a modification of my invention as hereinafter described.
The same letters of reference indicate the same or corresponding parts in all
the Figures of the drawings.
A is one of the bottom fork sides of a bicycle frame, B1 B2 are the two brackets
which carry the back wheel axle C one of which namely B₁ is fixed to the end of
the fork side A and the other namely 132 is fixed to the end of the other fork side
which lies behind the tube A and is not shewn upon my drawing. D¹ D³ are the
two back stays which connect the brackets B₁ B to the seat pillar lug. E is
the sprocket pinion fixed on the hub of the back wheel which revolves on the
axle C and F is the endless driving chain which passes round the sprocket pinion E
and round a corresponding sprocket wheel on the crank axle.
In carrying out my Invention the back wheel axle C is mounted eccentrically in
the two worm wheels G1 G2 one of which namely G' is shewn separately by Fig. 5
the wheel axle C passing through the eccentric holes g¹ in the worm wheels.
These worm wheels G G turn respectively in circular recesses 61 62 formed in
the faces of the brackets B1 B2 respectively or the said worm wheels may be
otherwise carried by the said brackets. Gearing with each of these worm
wheels G G2 there is a worm or screw which worms or screws are respectively
marked H H the spindles h¹ of which turn in lugs or bearings formed on or
fixed to the bracket parts 61 63 each of these worm spindles h¹ having a milled
head or being otherwise formed so that it can conveniently be turned. As before

page_text: stated the holes g in the worm wheels G1 G2 through which the back wheel
axle C passes are out of the centre of the worm wheels so that when the worm
wheels G G are turned by the worms H¹ H2 in one direction the wheel axle C
will as shewn in Fig. 1 be moved nearer to the crank axle, that is towards the
left hand side of the drawing thereby slackening the driving chain F and when
the worm wheels G1 G2 are turned in the opposite direction the back wheel axle C
will as shewn in Fig. 2 be moved farther from the crank axle that is towards the
Thus the
right hand side of my drawing thereby tightening the driving chain F.
tension of the chain F can be adjusted to the greatest nicety. The said
brackets B1 B2 of the bicycle frame have each a curved slot 6 formed in them so
as to permit of the proper movement of the back wheel axle C and each of these
slots has an opening 65 at one end so that the back wheel axle C can readily be
removed. When the usual nuts c¹³ on the ends of the wheel axle C are tightened
up they clamp the worm wheels G1 G2 tightly to their respective brackets B¹ B²
and thus effectually prevent the position of the worm wheels G1 G2 and the back
wheel axle C changing when they have once been set.
The worms HH2 are by preference although not necessarily arranged above the
worm wheels G1 G2 as shewn so as to be out of the way of the nuts c¹ c² on the
ends of the back wheel axle.
Instead of the lugs or bearings 63 which carry the worm spindles h¹ being formed
with the back brackets B1 B2 of the bicycle frame as above described each of these
lugs or bearings 63 may be formed as shewn in Fig. 6, 7 and 8 with a sheet
metal or other disc or plate 66 which fit in the recesses 61 62 in the back fork
brackets B1 B2 behind the worm wheels G¹ G these discs 66 being slotted to
correspond with the slots 64 b in the bracket parts B1 B2, and they are prevented
from turning by the lug parts 63 fitting in corresponding recesses 67 in the bracket.
Fig. 8 is a separate view of one of the said plates 66 made with the lugs b³.
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:-
1. In safety bicycles and other velocipedes and motor vehicles where the driving
wheel is driven by an endless chain, the herein described improved means for
adjusting the position of the axle of said driving wheel so as to regulate the tension
of the endless driving chain, that is to say, mounting the ends of said axle
eccentrically in two worm wheels mounted in bearings in the frame of the machine
and provided with two worms gearing with said worm wheels said parts being
so arranged that by turning the worms and worm wheels in one direction the
axle carried thereby will be so moved as to tighten up the endless driving chain
and by turning the worms and worm wheels in the opposite direction the said
axle will be so moved as to slacken the said endless driving chain, substantially
as hereinbefore set forth.
2. In safety bicycles and other velocipedes and motor vehicles where the driving
wheel is driven by an endless chain, the combination with the driving wheel axle
of the two worm wheels G1 G2 mounted eccentrically on the ends of said axle,
the brackets B1 B2 made with recesses b¹ 62 in which the worm wheels fit and
slotted at 6 65 to allow of the movement of the said axle and the worms H¹H²
carried by said brackets and gearing with the worm wheels the parts being con-
structed arranged and operating substantially as hereinbefore described with
reference to Figs. 1, 2, 3, 4 and 5 of the accompanying drawings.
3. In safety bicycles and other velocipedes and motor vehicles where the driving
wheel is driven by an endless driving chain, the combination with the driving
wheel axle of the two worm wheels G G2 mounted eccentrically on the ends of
said axle, the brackets B1 B2 made with recesses 162 in which the worm wheels
fit and slotted at b 65 to allow of the movement of the said axle, the circular
plates 66 fitting in said recesses and made with lugs 63 63 and the worms H¹ H2
carried by said lugs and gearing with the worm wheels, the parts being con-

page_text: structed arranged and operating substantially as hereinbefore described with
reference to Figs. 6, 7 and 8 of the accompanying drawings.
Dated this 20th day of October 1897.
CHARLES BOSWORTH KETLEY,
Agent for the Applicant.