Improvements in Chain Wheels and Driving Chains for Bicycles, Tricycles, and other Velocipedes, and Chain Driven Machinery generally.
Year: 1896

page_text: Date of Application, 4th Jan., 1806
Complete Specification Left, 26th Sept., 1996-Accepted, 31st Oct., 1895
PROVISIONAL SPECIFICATION.
Improvements in Chain Wheels and Driving Chains for Bicycles,
Tricycles, and other Velocipedes, and Chain Driven Machinery
generally.
I, FRANCES ELLIS, of No. 42 St. Luke's Road Clapham, London, Widow,
Teacher, do hereby declare the nature of this invention to be as follows:-
My invention consists of the improvements hereinafter described in the chain
wheels and driving chains of bicycles, tricycles and other velocipedes and chain
driven machinery generally whereby the adjustment of the tension of the driving
chain may be effected from time to time to compensate for wear in a simple,
efficient and expeditious manner.
I will describe my invention in connection with the chain wheels and driving
chain of a safety bicycle.
In constructing a chain wheel according to my invention I make the said wheel
of three parts namely a toothed or middle part and two side parts on which latter
the sides of the links of the chain bear in working on the chain wheel. The
peripheries of the two side parts are not circular but have teeth somewhat
resembling the teeth of a ratchet wheel, that is, the said teeth are wedge shapel
the thin ends of the wedges on the upper side of the wheel pointing in the direction
of the forward motion of the bicycle. I do not however bind myself to driving
them in this direction. The three parts of the wheel are secured together by
screw pins passing through holes in the two side parts of the wheel and through
slots in the toothed or middle part of the wheel. On the screwing up of the said
screw pins the three parts of the wheel are clamped rigidly together. On relaxing
the screws the side parts of the wheel may be turned through a small angie
independently of the middle or toothed part the screws working in the slots referred
to in the said middle or toothed part of the wheel.
I construct the chain to be used with the chain wheels hereinbefore described as
follows. I make the side liuks of the chain from blanks of sheet metal semi-
circular at their ends the longer edges of the said blank being parallel. Instead
of making the perforations in the said links for the pins or rivets connecting the
said side links to the middle links concentric with the semi-circular ends I make
the said perforations eccentric so that an imaginary line joining the centres of the
perforations in the said side links shall make an angle with the longer parallel edges
of the links equal or nearly equal to that of the wedge like teeth of the side parts
of the chain wheel.
When it is desired in consequence of wear of the chain wheel or of the chain or
in consequence of the elongation of the chain to increase the pitch of the chain
wheel the fixing screws of the chain wheel are relaxed and the sile parts of the
wheel are turned forward upon the middle or toothed part. By this action the
wedge like teeth of the sides of the wheel are made to slide under the side links of
the chain resting on them and the said links are consequently pushed out, that is
to say, the diameter of those parts of the wheel on which the side links rest is by
the action described virtually increased until the pitch of the wheel becomes equal
to the pitch of the chain.
After the re-adjustment of the tension of the chain the screw pins of the chain
wheel are screwed up and the parts of the wheel locked together.

page_text: The improvements in the chain wheels hereinbefore described may be applied to
both or to one only of the chain wheels of the safety bicycle.
Although I prefer to use with my improved chain wheels driving chains of the
kind hereinbefore described yet I do not limit myself thereto as driving chains
of the ordinary kind may be used with the said chain wheels with nearly the
same effect.
Dated this Fourth day of January 1896.
W. T. WHITEMAN,
Agent for the Applicant.
Improvements in Chain Wheels and Driving Chains for Bicycles,
Tricycles, and other Velocipedes, and Chain Driven Machinery
generally.
I, FRANCES ELLIS, of No. 42 St. Luke's Road, Clapham, London, Widow,
Teacher, do hereby declare the nature of my 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 consists of the improvements hereinafter described in the chain
wheels and driving chains of bicycles tricycles and other velocipedes and chain
driven machinery generally, whereby the adjustment of the tension of the driving
chain may be effected from time to time to compensate for wear in a simple,
efficient and expeditious manner.
I will describe my invention in connection with the chain wheels and driving
chain of a safety bicycle.
In constructing a chain wheel according to my invention I make the said wheel
of three parts, namely a toothed or middle part and two side parts, on which latter
the sides of the links of the chain bear in working on the chain wheel. The
peripheries of the two side parts are not circular but have teeth somewhat
resembling the teeth of a ratchet wheel; that is, the said teeth are wedge shaped,
the thin ends of the wedges on the upper side of the wheel pointing preferably in
the direction of the forward motion of the bicycle. The three parts of the wheel
are secured together by screw pins passing through holes in the two side parts of
the wheel and through slots in the toothed or middle part of the wheel. On the
screwing up of the said screw pins the three parts of the wheel are clamped
rigidly together. On relaxing the screws the side parts of the wheel may be
turned through a small angle independently of the middle or toothed part, the
screws working in the slots referred to in the said middle or toothed part of the
wheel.
I construct the chain to be used with the chain wheels herein before described as
follows. I make the side links of the chain from blanks of sheet metal, semi-
circular at their ends, the longer edges of the said blank being parallel. Instead
of making the perforations in the said liuks for the pins or rivets connecting the
said side links to the middle links concentric with the semi-circular ends 1 make
the said perforations eccentric so that an imaginary line joining the centres of the
perforations in the said side liuks shall make an angle with the louger parallel edges
of the links equal or nearly equal to that of the wedge like teeth of the side parts
of the chain wheel.
When it is desired in consequence of wear of the chain wheel or of the chain or
in consequence of the elongation of the chain to increase the pitch of the chain
wheel the fixing screws of the chain wheel are relaxed and the side parts of the
wheel are turned forward upon the middle or toothed part. By this action the

page_text: wedge like teeth of the sides of the wheel are made to slide under the side links of
the chain resting on them and the said links are consequently pushed out, that is
to say, the diameter of those parts of the wheel on which the side links rest is by
the action described virtually increased until the pitch of the wheel becomes equal
to the pitch of the chain. After the re-adjustment of the tension of the chain the
screw pins of the chain wheel are screwed up and the parts of the wheel locked
together.
Figures 1 and 2 of the accompanying drawing represent in side elevation a
chain wheel and driving chain constructed according to my invention applied to
the rear wheel of a safety bicycle, Figure 1 shoving the said chain wheel and chain
before wear and Figure 2 showing the saine after adjustment of the chain wheel to
compensate for wear; Figure 3 represents a portion of the said chain wheel and
chain in section the said section being taken on the dotted line x, x Figure 1.
Figure 4 represents in side elevation and Figure 5 in edge view, my improved
chain wheel detached; Figure 6 is a section of the said wheel on the dotted
line y, y Figure 4; Figures 7, 8 and 9 represent the parts of the said chain wheel
separated.
The same letters of reference indicate the same parts in the several figures of
the drawing.
The improved chain wheel is made in three parts, a middle toothed part
represented detached in Figure 7 and two side or ring parts marked respectively b, c
and shown separately in Figures 8 and 9. The peripheries of the said ring parts b, c
resemble in shape the peripheries of ratchet wheels. On the ratchet or wedge like
teeth of the rings b, c, the side links d, d of the driving chain bear in working on
the chain wheel as will be best seen by reference to Figure 3. The three parts of
the wheel are connected together by screw pins e, e, e which pass through holes
in the side ring b and through slots a' in the middle toothed part a and take into
screwed holes in the side ring c. When the said screws e are driven tightly home
the three parts a, b, c of the chain wheel are clamped or locked together, but on the
slackening of the said screwse the side rings b, c may be turned through a small
angle ou the middle toothed part a, the screw pins e, e, e working in the slots a¹ of
the said middle toothed part a. It will be seen by reference to Figures 1 and 2
that the side rings b, c are turned in the direction of the arrow on the ring bin
Figure 1 and the diameter and pitch of the chain wheel are virtually increased as
will be seen by a comparison of Figures 1 and 2, Figure 1 showing the parts before
any adjustment is required and Figure 2 showing the parts after adjustment to
compensate for wear. It will he understood that by the increase of the diameter
and pitch of the chain wheel described any slackness due to the stretching of the
chain or due to the wear of the chain or wear of the chain wheel is taken up and
the smooth working of the chain thereby ensured.
The improvements in the chain wheels hereiubefore described may be applied to
both or to one only of the chain wheels of the safety bicycle.
In order that the edges of the side links of the driving chains used with the
improved chain wheels may take a flat bearing on the wedge like teeth of the side
rings of the said chain wheels I make the said driving chains in the following
manner.
The improved driving chain differs from the ordinary chain known in commerce
as "block" chain in the respect that the holes for the joint pins or rivets f,f to
pass through, which joint pins connect the side links d, d with the middle links or
blocks 9, 9, are made eccentric to the semi-circular ends of the side links d, d
instead of concentric. The said holes for the rivet pins f, f (see Figures 1 and 2)
are preferably made so that an imaginary line joining their centres makes an
angle with the longer parallel edges of the side links d, d equal or nearly equal
to that of the ratchet or wedge like teeth of the side or ring parts b, c of the chain
wheel.
Although I prefer to use with my improved chain wheels, driving chains of the
kind herein before described and represented yet I do not limit myself thereto as

page_text: driving chains of the ordinary kind may be used with the said chain wheels with
nearly the same effect.
Having now particularly described and ascertained the nature of my invention
and in what manner the same is to be performed I declare that I claim as my
invention of "Improvements in chain wheels and driving chains for bicycles,
tricycles and other velocipedes and chain driven machinery generally,"
First. The improvements in chain wheels hereinbefore described and represented
in the accompanying drawing, the said improvements consisting essentially in
forming the side parts of the wheel, on which side parts the side links of the
driving chain bear, separate from the middle or toothed part and with wedge or
ratchet like teeth, the said side parts of the wheel being capable of adjustment
on the middle toothed part substantially as and for the purpose herein before
described and illustrated."
Secondly. In driving chains, making the pin or rivet holes in the side links of
the chain eccentric to the semi-circular ends of the said side links substantially as
and for the purpose hereinbefore described and illustrated in the accompanying
drawing.
Dated the Sixteenth day of September 1896.
FRANCES ELLIS.