Improvements in the Driving Mechanism of Bicycles, Tricycles, and other Velocipedes.
Year: 1896

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 11 of the Patents, &c. Act, 1883) as required by
the decision of the Comptroller General of the 4th day of February 1898.
Date of Application, 27th Oct., 1896
Complete Specification Left, 27th July, 1897-Accepted, 18th Sept., 1897
PROVISIONAL SPECIFICATION.
Improvements in the Driving Mechanism of Bicycles, Tricycles, and
other Velocipedes.
We, GEORGE PILKINGTON MILLS of The Woodlands" Beeston, in the County
of Nottingham, Civil Engineer, and THEODORE JAMES BIGGS, of 50 Raleigh Street,
Nottingham, Mechanical Engineer, do hereby declare the nature of this invention
to be as follows:-
Our invention relates to improved methods for the fitting of the detachable
or interchangeable chain wheels or gear wheels, used on bicycles, tricycles or
similar velocipedes, to the outer ends of the radial driving arms to which they
are fixed, & to the fitting of them in such manner that the screw pins or bolts
which are used to attach the chain wheel to the said arms are relieved from all
driving strain, & tne ariving strain is borne by suitable projections or shoulders
formed on the face of the driving arm. The driving arms may be fixed on the
crank shaft or may be made in one piece with the pedal crank, according to
common practice. It is customary to form a projecting curved shoulder or rib
on the face of each driving arm, the outer face of such shoulders being turned
so as to ensure their being concentric with the crank shaft, & the chain wheel
has a portion which is bored out or otherwise accurately made to fit over these
shoulders, thus ensuring the whole chain wheel being concentric with the shaft.
By our invention we use these shoulders for another purpose also; viz. to engage
with portions of the web of the chain wheel in such manner as to take all the
driving strain.
These said shoulders usually extend right across the face of the arm, their
length being equal to the width of that portion of the arm at which they are
located, but by our invention we may make them shorter, so that they do not
reach to the edge of the arm, the object of this being that after having been
accurately cut to length & equidistant from the shoulders on the other arms, they
are not affected by the filing or polishing of the edges of the arms, as the ends
of the shoulders stand inside clear from the edges of the arms, & the tools do not
touch them. According to our invention we make the web of the chain wheel
of even thickness, & portions of the said chain wheel web are cut out accurately
to receive the shoulders on the riving arms. The width of these spaces or gaps
thus made is exactly equal to the length of the shoulders on the driving arms,
so that the end faces of the said shoulders fit accurately in the gaps in the chain
wheel web & thus take all backward & forward driving strain without any
play. To hold the chain wheel concentric with the shaft, we either form a ring
or annular flange or parts thereof on one face of the chain wheel, the said flange
fitting over the outer faces of the shoulders on the driving arms, or we bore out
a shallow step or recess in the web of the chain wheel & cause this to fit over the
shoulders on the drving arms. When the chain wheel has been fitted to the driving

page_text: arms, with the face of the arms in contact with one face of the web of the
chain wheel, & the shoulders on the driving arms fitting into the respective gaps
in the chain wheel web, then the whole is secured in position by screw pins or
studs to receive which large clearance holes are provided in the chain wheel web
& tapped holes in the arm, or vice versa. Or bolts may be used for the same
purpose, in which case the driving arms & the chain wheel web are both provided
with clearance holes to receive the bolts.
Ac:ding to one arrangement, gaps are cut in the web of the chain wheel
of correct width to fit the end faces of the shoulders on the driving arms & thus
take the backward or forward driving strain without play, these shoulders project
a sufficient distance from the faces of the driving arms to allow of their stand-
ing through the web of the chain wheel far enough for an annular flange or ring
which is formed on the face of the web of the chain wheel to fit over & take a
seating on the outer faces of the said shoulders on the arms & thus ensure the
chain wheel being concentric with the shaft.
By another method gaps are cut in. the chain wheel web, into which the end
faces of the shoulders on the driving arms fit so as to take the driving strain,
but instead of using a flange or ring on the face of the chain wheel web, a slight
circular recess or step is sunk into the web of the wheel & is made of such internal
diameter as to fit over the outer faces of the shoulders on the driving arms &
thus hold the chain wheel concentric.
By another arrangement the gaps are cut in the chain wheel web to fit the
end faces of the shoulders on the driving arms but to stand clear of the outer
faces of the said shoulders. The extreme ends of the driving arms are accurately
turned & an annular flange or ring or parts thereof is formed on the face of
the chain wheel web, the internal diameter of the said flange is of the correct size
to fit over & take a seating on the extreme ends of the arms, & thus hold the
chain wheel concentric.
By another arrangement the web of the chain wheel is made perfectly plain
on each face & the gaps through the web are accurately cut to fit the three faces
of each of the shoulders on the driving arms, namely, the two end faces to take
the driving strain & the outer face to hold the wheel concentric. By this method
it is not necessary to form a flange on the face of the chain wheel web to hold the
chain wheel concentric, nor to bore a recess or step for the same purpose.
By another arrangement the chain wheel web is made perfectly plain on each
face & gaps are cut in the said web, to fit the end faces of the shoulders on the
driving arms, & another curved shoulder is also provided on each of the driving
arms, these said other shoulders being of greater length than the width
of the gaps in the chain wheel web they extend sufficiently on each side of the
said gaps to allow the inner edge of the chain wheel web to fit over them & thus
the chain wheel is held concentric.
In each of the before described arrangements, bolts & nuts, or screw pins,
or studs and nuts are used to secure the chain wheel to the driving arms as before
described.
Dated this 24th day of October 1896
GEORGE PILKINGTON MILLS,
THEODORE JAMES BIGGS,
Applicants.
COMPLETE SPECIFICATION (AMENDED).
Improvements in the Driving Mechanism of Bicycles, Tricycles, and 50
other Velocipedes.
We, GEORGE PILKINGTON MILLS of "The Woodlands" Beeston, in the County
of Nottingham, Civil Engineer, and THEODORE JAMES BIGGS of 50 Raleigh Street,

page_text: Nottingham, Mechanical 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 relates to detachable or interchangeable sprocket wheels for
velocipedes, and it consists of certain improvements in the details of construction
whereby the screw pins or bolts used to attach the said wheel to the radial crank
arms are relieved of all driving strain.
In the accompanying drawing:-
Figure 1 is a broken view in front elevation showing the upper portion of one
of the radial crank arms connected to the sprocket wheel according to one method
of carrying out our invention.
Figures 2 and 3 are broken views in transverse section on lines y-y and -
respectively of Figure 1.1
Figure 4 is a broken view in side elevation showing another method of carrying
our invention into effect.
Figure 5 is a broken view in transverse section on line y-y Figure 4.
Figure is a broken view in side, elevation showing another modification of
our invention.
Figures 7 and 8 are broken views in transverse section on lines a- and y-y
Figure 6.
Figure 9 is a broken view in side elevation showing a further muslification of
our invention.
Figure 10 is a broken view in transverse section on line y-y Figure 9.
Figure 11 is a broken view in side elevation of another form our invention
may assume, and
Figures 12 and 13 are broken views in transverse section on lines and
yy Figure 11.
Throughout the views similar parts are marked with like letters of reference.
The radial arms A adapted to be fixed on the crank shaft or preferably made
in one with the crank are furnished on one of their faces with transverse pro-
jecting shoulders a, which are adapted to engage with spaces or recesses on the
inner edge of the web b of the sprocket wheel B. The shoulders « are preferably
of a width appreciably less than that of the portions of the arms A at which they
are located, the object being that after having been accurately cut to width to
fit the spaces or recesses in the web b of the sprocket wheel B, they are not affected
by the subsequent grinding or polishing of the edges of the arms A.
To ensure the wheel B being concentric with the crank shaft various methods
may be employed. In Figures 1, 2 and 3 the shoulders a are turned on their
faces a concentric with the shaft and are adapted to accurately engage with the
concentrically turned inner face of a flange formed on the web of
the wheel B. In Figures 4 and 5 the faces a of the shoulders a engage with the
concentrically turned inner face of a step or recess b¹ formed in the outer side
of the web b In Figures 6, 7 and 8 the faces a' of the shoulders a engage with
the concentrically turned inner face of a step or recess b¹ formed in the inner
side of the web b.
In the construction shown by Figures 9 and 10 the spaces or recesses in the webb
are accurately and concentrically formed (which it will be understood need not
be the case in the constructions herein before described) so as to engage with the
concentric faces a¹ of the shoulders a.
In the construction shown by Figures 11, 12 and 13, flanges a are formed on
the shoulders a and engage with the recesses in the web b of the wheel B and
the concentrically turned faces a¹ engage with the concentrically turned inner
edge of the web b.
Bolts or screw pins X are provided as usual for securing the wheel B to the
arms A, a sufficient clearance being provided in the holes through the web b
so as to allow the shoulders a to transmit the whole of the driving strain to the
wheel

page_text: To enable a good fit to be obtained between the shoulders a of the arms A and
the web b of the sprocket wheel B we prefer to cut or fashion one or both of the
said parts so that they do not engage at the shoulders or angles.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we would have it.
understood that we are aware of the Specification of Letters Patent No. 9389
of 1895 granted to Frederick John Osmond and we do not claim anything described
and claimed therein, but we declare that what we claim is:-
(1). The combination of parts herein described and illustrated by the accom-
panying drawing forming our improvement in the driving mechanism of bicycles,
tricycles and other velocipedes.
(2). In a cycle, the combination of arms A mounted on the axle or formed
in one with one of the cranks and having transverse projecting shoulders such
as a on their faces, and of a sprocket wheel B having a series of spaces or recesses
in its web b adapted to receive the projecting shoulders on the arms, as and for
the purpose herein specified.
Dated this 07th day of July 1807
ROBERT E. PHILLIPS, Assoc. M. Inst. C.E., M.I. Mech. E.
Consulting Engineer & Patent Agent,
70, Chancery Lane, London, W.C., Agent for the Applicant.