Improvements in or relating to Bicycles.
Year: 1897

page_text: Date of Application, 10th Aug., 1897
Complete Specification Left, 10th May, 1898-Accepted, 10th Aug., 1898
PROVISIONAL SPECIFICATION.
Improvements in or relating to Bicycles.
I, THOMAS MORTON SCHOFIELD, of 113, Sussex Road, Southport, in the County.
of Lancaster, Engineer, do hereby declare the nature of my said invention to be
as follows:-
These improvements refer to cycles in which the motion of the crank is trans-
mitted to one of the wheels by chain gearing and the said improvements relate
more particularly to what is known as the "safety" bicycle.-As such machine
is at present made the chain wheel used for transmitting motion is arranged upon
the end of the crank axle and outside the bottom bracket," and owing to the
distance the said wheel is, in consequence, removed from the centre line or plane
of the machine, and there being no counteracting part on the opposite end of
the axle to compensate, the pull or strain on the wheel in pedalling is very liable
to twist or distort the bearing, or in any event greatly diminish the smooth and
even running of the machine.
The object of my improvements is to overcome such liability to derangement, or in
other words to bring the driving mechanism as near as possible to the centre line,
or plane of the machine.
În carrying out my invention I form the "bottom bracket," or those parts which
form the bearing of the crank axle, of a fork-like character, and, by preference, of
half-round section, in lieu of the single solid bracket heretofore used. The chain-
wheel which transmits the motion of the axle to the rear (or front) wheel of the
machine I mount inside, or between the forked extremities aforesaid, and as near
the centre line of the machine as possible consistent with the hereinafter described
mounting of the chain pinion. With the chain wheel so placed, and to enable the
ball bearings of the axle at that side to be adjusted when required,-which cannot
be conveniently done in the ordinary way, I screw thread the axle with a fine
thread and in the end of the axle I form small notches or recesses for one or more
"keys or feathers," and in the "eye" of the crank I form one or more corre-
sponding notches.
33
وو
When the bearing is slack and requires tightening up, the "feather" is removed,
and the crank (or axle) is then rotated for say a quarter of a revolution, or to such
an extent that will ensure of the slack being taken up.-When so adjusted the
"feather
is again placed in the notche, which comes opposite that in the crank,
and in such manner the bearings are adjusted. To prevent the small feather fall-
ing out, and becoming lost, I cover the end of the axle with a thin cap or disc,
fixed centrally or otherwise to the crank or axle by set screw.
The ball bearing of the opposite end of the axle is adjusted in the ordinary
way, but to allow for the adjustment of the cranks, I also screw thread this end
of the axle with a fine thread, and provide it, and the crank eye with notches and
'feather," and cap or disc to retain the feather, and by the turning of which
and adjustment of the feather into one of the notches the cranks are set and locked
at their proper relative angles.
66

page_text: 66
The pedal spindle or axis is adjusted and fixed in a similar way, and the
"
feather covered by a disc which takes into the opening for the spindle, and
lies flush with the rear face of the crank.
The plane of the chain-wheel being removed as aforesaid an inch or more nearer
the plane of the machine, it is necessary to move the pinion on the wheel hub
into line with it, and to do which must necessitate the narrowing of the wheel
without diminishing the lateral rigidity thereof. In lieu of taking the spokes
direct from the ordinary hub to the wheel rim, I take them from what I will call
an extra or supplementary hub, made of spokes, transversely joined, & each side
more or less parallel, with diagonally disposed spokes to act as stays or tie rods
in giving lateral rigidity to the wheel. To this so called supplementary hub, I
connect the spokes leading to the rim of the wheel, and arrange them in any
desired pattern, but preferably straight and tangential alternately.
This peculiar construction of wheel permits of the hub, or space between the
sides of the wheel being contracted to an extent which allows of the chain pinion
being in line with the chain wheel within the aforesaid bracket without decreas-
ing the lateral rigidity of the wheel.-The peculiar mounting of the chain-wheel
also effects the desired improvements without extending the width of
"tread."
Dated this 9th day of August 1897.
Improvements in or relating to Bicycles.
I, THOMAS MORTON SCHOFIELD, of 113, Sussex Road, Southport, in the County
of Lancaster, Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement; -
These improvements refer to bicycles in which the motion of the crank is trans-
mitted to one of the wheels by chain gearing, and the said improvements relate
more particularly to what is known as the safety" bicycle. As such machine
is at present made the chain wheel used for transmitting motion is arranged upon
the end of the crank axle, outside the bottom bracket, and owing to the distance
the said wheel is, in consequence, removed from the centre line or plane of the
machine, and there being no counteracting part on the opposite end of the axle
to compensate, the pull or strain on the wheel in pedalling is very liable to
twist or distort the bearing, or in any event greatly diminish the smooth and
even running of the machine.
The object of my improvements is to overcome such liability to derangement, or in
other words, to bring the driving mechanism as near as possible to the centre line
or plane of the machine.
In carrying out my invention I form the bottom bracket or those parts of the
frame which carry the crank axle of fork-like character, and, by preference, of
half round section in lieu of the single solid bracket heretofore used. The chain
wheel which transmits the motion of the axle to the rear (or front) wheel of the
machine, I mount inside or between the divided bracket aforesaid, and as near
the centre line of the machine as possible and consistent with the hereinafter
described mounting of the chain pinion. With the chain wheel so placed and to
enable the ball bearings of the axle at that side to be adjusted when required,
and which cannot very well be done in the ordinary way, I screw thread the
axle with a fine thread, and in the end of such axle I form small notches or

page_text: recesses for one or more "keys" or "feathers" and in the eye of the crank I
form one or more corresponding notches. When the bearing is slack and requires
tightening up the "feather" is removed and the crank (or axle) is then rotated for
say a quarter of a revolution or to such an extent that will ensure of the slack
being taken up. When so adjusted the "feather" is again placed in the notch
which comes opposite that in the crank and in such manner the ball bearings
are adjusted. To prevent the small feather falling out, and becoming lost, I cover
the end of the axle with a thin cap or disc, fixed centrally to the crank or axle
by set screw.
The ball bearing at the opposite end of the axle is adjusted in the ordinary way,
but to allow for the adjustment of the cranks to their proper relative angles, I
also screw thread this said opposite end with a fine thread, and provide it and
the crank eye with a feather and notches, and a cap or disc to retain the feather,
and by the turning of which and adjustment of the feather in one of the notches
the cranks are set and locked at their proper relative angles.
The pedal spindle is also adjusted or fixed in the crank in a similar manner,
and the feather covered by a disc which takes into the opening for spindle, and
lies flush with the rear face of the crank.
The plane of the chain wheel having thus been moved as aforesaid an inch or
more nearer the plane of the machine, it is necessary to move the pinion on
the wheel hub into line with it and to do which necessitates the narrowing of the
wheel without diminishing the lateral rigidity thereof. In lieu of taking the
spokes direct from the ordinary hub to the wheel rim, I take them from what I will
call an inner or supplementary hub made of spokes or wires transversely joined
and each side more or less parallel with diagonally disposed spokes to act as stays
on the rods in giving the desired lateral rigidity to the wheel. To this supple-
mentary hub, I connect the spokes leading to the rim and arrange them in any
suitable pattern, but preferably straight and diagonal alternately.
The peculiar construction of wheel permits of the hub or space between the
sides of the wheel being contracted to an extent which allows of the chain pinion
being placed in line with the chain wheel within the aforesaid bracket without
decreasing the lateral rigidity of the wheel.
And in order that our said invention may be more readily understood and
carried into practical effect I have hereunto annexed two sheets of drawings and
will now proceed to describe the same with the various figures and letters of
reference marked thereon.
On sheet one.
Fig. 1 is a part side elevation and Fig. 2 a part plan of a safety bicycle with
my improved gearing shewn applied thereto.
On sheet two,
Fig. 3 is a vertical section of the crank shaft and bottom bracket, and Figs. 3 4
and 5 represent details.
In accordance with my invention (A) represents the crank shaft and (B) the
chain wheel. For the purpose of placing such wheel as near the plane of the
machine as possible, the bottom bracket (C) of the machine frame is divided or
forked as shewn more clearly in Fig. 2 and 3 and the wheel placed between the
forks. To allow of the chain pinion (B) on the wheel hub being in line with the
said wheel (B) the width of the wheel (D) at the hub requires to be reduced and
to allow of, and effect, such reduction, I employ the supplementary hub or rim (E),
and mount such hub or rim upon the hub (F) by radial spokes (G) and diagonal
and tangential spokes (H) (see Fig. 2). To this supplementary hub I connect
the rim (I) of the wheel by ordinary spokes, or by spokes arranged after the
manner of the spokes (G) and (H). In practise I find that with spokes arranged
after the manner of spokes (G) and (H) I can, for ordinary single machines, dis-
pense with the hub (E) and effect the reduction of width direct from hub (F), but
for tandem or multicycle machines it is best to employ the supplementary hub,

page_text: For effecting the adjustment of the chain wheel (B), or for tightening up the
ball bearings and setting the cranks at their proper relative positions, I screw
thread the axle (H) as shewn more clearly in Fig. 3 at each end. In each end I
also form a series of notches (J) corresponding to a similar series of notches (J¹)
in the eye of the crank (K). The thread upon the axle is a fine one, and meshes
with corresponding threads in the eyes of cranks (K), and (K¹).
The wheel (B) forms part of, or is keyed to the axle, and one side is cupped
out to form one half of a ball bearing. Each crank is also cupped to form one
half of a ball bearing, and the other halves of such bearings are
formed by bushes (L) clamped by straps (N) of the bottom bracket, forks.
prevent such bushes moving they are provided with a small notch or peg (N¹)
engaging with a like peg or notch on the bracket (C).
To
When the cranks require adjusting they are rotated on the screwed end of the
shaft and when set to their proper position (at which one or other of the notches in
shaft (A) comes opposite those in the crank eye) pins or pegs (0) are placed in
such notches, and such pegs are (by preference) formed in one piece with a disc
or cap (P) which after adjustment of the cranks serves to cover up the notches,
and by means of a screw (Q) fixing it on the crank end serves to hold the pegs
in their notches.
By this adjustment of the cranks and method of mounting the chain wheel I
greatly reduce the tread of the pedals and to further reduce such tread I employ the
same means for securing the pedals (see Fig. 3); providing the pedal axle with
notches and the eye of the crank with notches, and a pegged disc (P¹) slightly
countersunk to lie flush with the face of the crank.
This improved method of adjusting and fixing cranks and pedals which may
be applied to machines as at present constructed is highly advantageous and is
particularly beneficial for ladies machines in that it absolutely avoids all projec-
tions on which a dress may catch. In like manner the arrangement of chain
and chain wheel within the frame enables the gear to be more effectually screened
than the present construction of machine.
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 a safety bicycle or the like, the employment of a forked bottom bracket,
in combination with chain gearing working within such bracket, and means for
enabling the "tread" to be reduced, as set forth.
2: In a safety bicycle or the like, the combination of a forked bottom bracket,
a chain wheel within such bracket, a crank shaft with screw threaded and notched
ends, in combination with cranks with notched eyes, as and for the purposes set
forth.
3: In a bicycle or like wheel the combination of hub (F), supplementary hub
(or rim) (E) and rim (I) supported by spokes arranged radially, diagonally and
tangential, as and for the purposes set forth.
4: The combination of pedal axle with notched extremities and crank with
notched eye, as set forth.
5: The disc (P) with pegs (0), as and for the purposes set forth.
Datadh 0th day of V 1808
THOMAS MORTON SCHOFIELD,
By John G. Wilson & Co., Agents.