Improvements in the Driving Gear of Velocipedes.
Year: 1897

page_text: Date of Application, 4th Jan., 1897
Complete Specification Left, 4th Nov., 1897--Accepted, 4th Dec., 1897
PROVISIONAL SPECIFICATION.
Improvements in the Driving Gear of Velocipedes.
We, JOSEPH HUNTER, of 139 Brownlow-Hill, Liverpool, Warehouseman, and
JOSEPH GEORGE HASSELL of 7 March Road, Anfield, Liverpool, Clerk, both in the
County of Lancaster do hereby declare the nature of this invention to be as
follows:-
This invention has for its object improvements in the driving gear of velocipedes
and similar machines, and it consists in the employment of an improved form
of gearing constructed in the manner herein set forth.
The main purpose of our invention is to produce a chain driving gear for
velocipedes which will allow the running of the machine to be more perfectly con-
trolled by means of the pedals than is possible in machines fitted with the ordinary
chain driving gear.
Further advantages of our improvements are reduced weight and cost, and the
non-dependence of the chain-wheels on perfect alignment which enables the chain
to run freely when the framework twists or springs during the application of force.
According to our invention we employ an endless chain passing over chain-
wheels fixed to revolve respectively with the driving-wheel hub and crank axle in
the manner hitherto generally, employed.
We employ a suitable chain having links which are capable of free movement
in two planes at right angles to one another, or in the plane of the chain-wheels
and at right angles thereto. We at present find most suitable a chain formed of
ordinary oval links of uniform shape and size.
The peripheral faces of the chain-wheels are preferably cylindrical. In some
cases they are grooved slightly concave.
The peripheral face of each chain-wheel has a sunk bed which is formed to follow
the outline of the chain, and in which that part of the chain passing round the chain-
wheel is embedded for about half its depth or more.
Sometimes the faces of the
chain-wheels are grooved and sunk to carry two or more chains of lesser size than
when one only is used.
D
1
100%
R. J. URQUHART,
57, Barton Arcade, Manchester,
6, Clayton Square, Liverpool,
Consulting Engineer and Patent Agent.

page_text: Clerk, 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 has for its object improvements in the driving gear of velocipedes
and similar machines, and it consists in the employment of the improved form or
construction of chain driving hereinafter set forth.
The main purpose of our invention is to produce a chain driving gear for veloci
pedes and similar machines or vehicles which will allow the running of the machine
er vehicle to be more perfectly controlled by means of the pedals or cranks than
is possible with machines fitted with the ordinary chain driving gear. The principie
upon which this invention is based is that of causing the chain to bind in the
bed instead of freely leaving it as the chain wheel rotates, when a back pressure
is applied to the driving chain wheel shaft.
According to our invention we employ an endless chain passing over chain wheels
fixed to revolve respectively with the driving wheel hub and crank axle or shaft
in the manner hitherto generally employed.
We prefer to employ a chain which has links capable of free movement in two
planes at right angles to one another, or in the plane of the chain wheels and at
right angles thereto. We find a chain formed of ordinary oval links of uniform
shape and size suitable to our purpose, but in order to obtain the desired effect with
as small a chain as is consistent with the strength required we use a chain in which
the carrying or horizontal links are more acute at one end than at the other or are
of an approximately heart shaped form. The chain wheels are formed with sunk
beds corresponding in form to that of those links of the chain which lie flat in the
bed. The links which lie in the plane of the chain wheel are partly sunk in a
groove formed in the centre of the peripheral surface of the chain wheel aforesaid.
In describing and illustrating by means of the annexed sheet of drawings, the
invention set forth herein, reference is made chiefly to the forms of chain herein
before referred to, which forms of chains illustrate well the principle upon which
our invention is based, but other suitable forms of chains may be used.
In the said drawings, Figure 1 represents part of a chain wheel formed with a
sunk chain bed instead of projecting teeth, and shewing several links of a chain
lying therein.
Figure 2 represents a cross section of part of the chain wheel and chain on
line
P, in figure 1.
Figure 3 is a plan of the portion of chain bed developed or flattened out and
sectioned along the pitch line, and of the chain illustrated in figure 1.
Figure 4 illustrates a few links of a chain having oval links of ordinary form,
partly in section.
Figures 5, 6, 7, and 8 are similar views illustrating in a similar mauner a modified
form of chain and chain bed.
The Figures are on an enlarged scale to show the construction more clearly.
Referring first to Figures 1. 2, 3 and 4, a represents the driving chain wheel
which is rotated in the direction indicated by the arrow A. groove a is formed
round the rim in which the vertical links of the chain blic. Sunk beds a² are
formed for the horizontal links 62 of the chain. These beds are preferably a shade
longer than the links and have slightly inclined walls round the latter ends or
halves of the beds as indicated by a³, Figures 1 and 2, which latter ends of the beds
bear against the horizontal links as illustrated in Figures 1 and 3 and carry the
chain round the wheel. The front ends or halves of the beds have vertical or
steeper sides, as illustrated at a Figures 1 and 3. In the modification illustrated
by Figures 5, 6, 7, and 8 the vertical links b¹.are oval as heretofore but the hori-
zontal links 62 are more acute at the front end than at the back end. The
sunk beds for the horizontal links are of corresponding form but are slightly
longer than thd links, sufficiently so to permit of
links wedging themselves in the leds thereof when back pressure is applied
the said horizontal
to the driving chain wheel. That part or end of each bed which

page_text: bears against the horizontal link, when carrying the chain, in a forward direc-
tion as indicated by the arrows, has a slightly inclined wall. In the case of a chain
wheel drawn round or driven by the chain, the front ends or halfs of the
horizontal link beds must have inclined walls so as to permit the links of the chain
to freely leave the beds as the chain passes tangentially from the wheel; the rear
ends or halfs of the link beds aforesaid have straight walls. In the case of chains
having alternate links of the form illustrated in Figures 5, 6, 7 and 8 the special
advantage of the acute ends of the links only applies to one of the chain wheels,
as in one instance the chain wheel drives the chain and in the other instance the
chain drives or carries round the chain wheel, so that in the first case the back of
the horizontal link is acted upon by the wheel and in the second case the front
of the same link acts upon the chain wheel.
As the wheel a rotates in a forward direction as indicated by the arrows the
inclined ends or walls a³ of the horizontal link bed a² hear against the latter ends
of the horizontal links and so carry the chain round with the wheel, the inclined
walls of the beds permitting the links to readily leave the beds-as-the-chain-passes-
tangentially from the chain wheel. When back pressure is applied to the chain
wheel the latter slips until the ends or walls at of the horizontal link beds come in
contact with the first part or half of the horizontal links, which ends at having
steep or contracted walls prevent each horizontal link leaving its bed without
binding and so friction is created in the chain gear tending to stop the driving
wheels of the machine.
In some cases the gear is so formed that all the links of the chain may bind in
leaving the chain wheel as it rotates. This may be done in the case of the form of
chain herein before referred to by contracting the groove in which the vertical
links lie at intervals and so forming the contractions that the links will bind
when the chain is moving in one direction.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
First. In velocipedes and other similar machines having endless chain driving
gear the use of a chain wheel or chain wheels which is or are formed to retard
by friction, when back pressure is applied to the driving chain wheel shaft, the
lifting of the links of the chain severally or alternately from the rim or rims of
the chain wheel or wheels as the chain passes tangentially from one chain wheel to
the other substantially as and for the purpose hereinbefore described and illustrated
in the annexed sheet of drawings.
Second. In velocipedes and other similar machines having an endless chain
driving gear the use of a chain in which the links severally or alternately are
formed to bind in leaving one or each chain wheel rim as the chain passes tan-
gentially from one wheel to the other when back pressure is applied to the driving
chain wheel shaft substantially as and for the purpose hereinbefore described and
illustrated in the annexed sheet of drawings.
Third. In velocipedes and other similar machines having endless chain driving
gear the improved construction or formation of the olternate links of the chain
and of the corresponding chain bed of the driving chain wheel for the purpose
of causing such links to bind in the bed as the chain masses tangentially from one
wheel to the other when back pressure is applied to the driving chain wheel shaft
substantially as hereinbefore described and illustrated with reference to Figures 5,
6, 7 and 8 of the annexed sheet of drawings.
Fourth. In velocipedes and other similar machines having endless chain driving
gear the use of an endless chain and chain wheels so formed or constructed that
when the gear is rotating in a forward direction the links of the chain freely leave
the chain wheels as the chain passes tangentially from one chain wheel to the other,
but when the gear is rotating in a backward direction or when back pressure is
applied to the driving chain wheel shaft the several or alternate links of the chain

page_text: bind as they leave the chain wheel or chain wheels and thereby brake the driving
wheel or wheels substantially as herein before described and illustrated in the
annexed sheet of drawings.
Dated this 3rd day of November 1897.
R. J. URQUHART,
57, Barton Arcade, Manchester,
Consulting Engineer and Patent Agent.