Improvements in Speed Gearing Mechanism for Velocipedes.
Year: 1895

page_text: Date of Application, 6th Dec., 1895
Complete Specification Left, 7th Sept., 1896-Accepted, 24th Oct., 1896
PROVISIONAL SPECIFICATION.
Improvements in Speed Gearing Mechanism for Velocipedes.
I, THOMAS PARISH, of 12, Jordan Street, Preston, in the County of Lancaster,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in speed gearing mechanism for
velocipedes of that class in which pitch chain driving gear is employed and consists
in the application either to the driving or driven sprocket wheel a contrivance for
increasing the diameter and for correspondingly increasing the number of teeth
on either of the said wheels with the result that the driving gear (of a bicycle
to be suitable for bigh speeds
for instance) may be readily altered so
or racing purposes or for slow speeds as when travelling uphill or against a
strong wind.
as
In carrying my invention into effect 1 employ a kind of collar made in three or
more segments jointed to each other the said collar being so formed as to fit over
or embrace the periphery of the sprocket wheel and having on its inner side
recesses corresponding to and going over the teeth on the sprocket wheel. On its
outer or periphery side the collar has teeth of the same pitch as the sprocket wheel
but of increased number as will be well understood. To enable the collar to be
attached to or unfastened from the sprocket wheel one of the joints is provided
with a removable pin or pivot bolt which may be screw-threaded and may be
locked in position in any convenient manner. It will be obvious that by increasing
the diameter of either of the sprocket wheels the ordinary driving chain would
either require to be lengthened-which would be inconvenient--or the distance
between the axes of the sprocket wheels would have to be shortened and to facilitate
the latter operation I make the usual horizontal slots within which is held the
axis of the back wheel longer than usual so as to provide greater scope than is at
present available. On existing machines I effect the lengthening of the slots by
means of a fork-like extension piece or bridge—in lieu of the ordinary cross bar-
and if required additional washers which I term "distance pieces" and use the
ordinary screws and nuts for tightening up the chain gearing in the usual way.
Dildo. of December 1895
Improvements in Speed Gearing Mechanism for v
I, THOMAS PARISH, of 12, Jordan Street, Preston, 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 ascertained in and
by the following statement :-
This invention relates to improvements in speed gearing mechanism for
› velocipedes of that class in which pitch chain driving gear is employed and consists

page_text: in the application either to the driving or driven sprocket wheel a contrivance for
increasing the diameter and for correspondingly increasing the number of teeth on
either of the said wheels with the result that the driving gear (of a bicycle-
for instance) may be readily altered so as to be suitable for high speeds or
racing purposes or for slow speeds as when travelling uphill or against a
strong wind.
In carrying my invention into effect I employ a kind of collar made in three or
more segments jointed to each other the said collar being so formed as to fit over
or embrace the periphery of the sprocket wheel and having on its inner side
recesses corresponding to and going over the teeth on the sprocket wheel. On
its outer or periphery side the collar has teeth of the same pitch as the sprocket
wheel but of increased number as will be well understood. To enable the collar to
be attached to or unfastened from the sprocket wheel one of the joints is provided
with a removable pin or pivot bolt which may be screw-threaded and may be locked
in position in any convenient manner. It will be obvious that by increasing the
dianeter of either of the sprocket wheels the ordinary driving chain would either
require to be lengthened-which would be inconvenient-or the distance between
the axes of the sprocket wheels would have to be shortened and to facilitate the
latter operation I make the usual horizontal slots within which is held the axis of
the back wheel longer than usual so as to provide greater scope than is at present
available. On existing machines I effect the lengthening of the slots by means
of a fork-like extension piece or bridge-in lieu of the ordinary cross bar--and
if required additional washers which I term "distance pieces" and use the
ordinary screws and nuts for tightening up the chain gearing in the usual way.
In the accompanying drawings,
Fig. 1 represents the toothed collar hereinabove described as it appears when
opened out or detached from the ordinary sprocket wheel and
Fig. 2 shews it in working position on the sprocket of the rear or driving wheel
the sprocket being indicated by broken lines.
Fig. 3 is a sectional detail view of a bicycle rear wheel axle and attendant parts
shewing certain alterations desirable to be made when my invention is applied
thereto and,
Fig. 4 is another detail view of a modified arrangement of certain parts shewn
at Fig. 3.
Fig. 5 is a side view and
Fig. 6 a plan view shewing the method of lengthening in existing machines
the horizontal slot within which the axle of the back or driving wheel is held.
Fig. 7 is a sectional view through one of the "distance pieces" hereinabove
referred to.
In the drawings the ordinary sprocket wheel is shewn as having eight teeth and
my improved overlapping toothed collar as having ten teeth.
a a are the segments of the outer collar jointed together at b b by means of metal
pins and connected when in position-as at Fig. 2-by means of a removable
screw-threaded pin c. When the collar is in working position over the sprocket
1 prefer to employ an annularly recessed plate p which fits on to a projecting
annulus d formed on one side of the segments a a for the purpose of holding the
said segments firmly together and to take the strain as far as possible off the
several joint pins bb. On existing machines I fasten the plate in position by
means of screws e e screwed into the ordinary sprocket wheelf (see Figs. 2 and 4)
but in new machines I prefer to make the said plate answer also as a screw nut p¹
(see Fig. 3) and to employ a lock nut p' screw-threaded in the opposite direction
to the nut pl. g is the horizontal slot within which the axle h is held by means of
the screw nuts ii and j is the screw-threaded spindle and j¹ the screw nut whereby
the tension of the chain gearing is adjusted. I prefer to make the axle h self-
contained so that the adjustment of the ball bearings may not be interfered with
when the holding nuts ii are loosened. o is an additional lock nut for preventing
the cones from becoming unscrewed or tightened.

page_text: At Figs. 5 and 6 is the fork-like extension piece or bridge for extending the
slot in existing machines and m is a "distance piece" which is preferably
fitted into the bridge by means of a tongue n dropped into a suitably shaped
groove.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is :-
1. In speed gearing mechanism for velocipedes the employment of a jointed
overlapping collar forming an enlarged and removable sprocket in manner
O substantially as hereinabove described and shewn in the drawings for the purpose
specified.
2. The mode of extending or lengthening the slot within which the axle of the
rear wheel of a velocipede is held substantially as hereinabove described and shewn
in the drawings