Improvements in or relating to Driving Gears for Cycles.
Year: 1894

page_text: Date of Application, 29th May, 1894
Complete Specification Left, 27th Feb., 1895-Accepted, 30th Mar., 1895
PROVISIONAL SPECIFICATION.
Improvements in or relating to Driving Gears for Cycles.
We RICHARD CAMPBELL, of 21, Monastery Road, Liverpool, in the County of
Lancaster and WILLIAM RAILTON, of 5, Goschen Street, Liverpool, aforesaid,
Engineers, do hereby declare the nature of this invention to be as follows:-
--
This invention has for its object a driving gear for bicycles, tricycles or the
like, which will enable a rider to drive his machine at a greater speed with no
greater exertion, or, in some cases, with even less expenditure of power, than
hitherto.
The essence of our invention consists in providing, in combination with each
driving crank, a stationary eccentric, the latter being so arranged as to vary or
control the operative length of the crank in such a way that a greater leverage on
the down-stroke can be obtained than during the up-stroke.
In carrying our invention into effect, the plan we prefer is to make the cranks
slotted, and in each of these slots to arrange a sliding block which carries the
treadle. These blocks are coupled by means of rods to eccentric straps or their
equivalent, which latter are mounted upon and are operated by an eccentric (or a
disc mounted eccentrically). The crank rotates with the spindle on which the
chain wheel is mounted, but the eccentric is fixed to the frame. The latter can,
however, be adjusted in any desired position.
The mode of action is as follows:-
In driving the machine, the crank will revolve on its axis in the ordinary way,
but, owing to the eccentricity of the two centres, namely, the centre of the crank
and that of the eccentric, the block that carries the treadle will slide up and down
in the crank, and thus will approach, or recede from, the centre on which the
crank rotates. It will be seen, therefore, that, on the down-stroke, a greater
leverage can be obtained than on the up-stroke of the crank, the latter being
practically a dead point so far as its influence in propulsion of the cycle is
concerned.
We, have described one way in which our invention can be carried into effect,
but it is obvious that alterations may be made in the construction and arrangement
of the various parts without departing from the object of our invention. Thus
instead of forming the cranks slotted, they may be made solid, and the treadles
attached to blocks sliding on vee cylindrical or other suitably shaped faces on the
cranks.
Dated this 28th day of Mo 1001

page_text: COMPILE STELICATION.
Improvements in or relating to Driving Gears for Cycles.
We, RICHARD CAMPBELL, of 21, Monastery Road, Liverpool, in the County
of Lancaster, and WILLIAM RAILTON, of 5, Goschen Street, Liverpool, aforesaid,
Engineers, 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 a driving gear for bicycles, tricycles or the
like, which will enable a rider to drive his machine at a greater speed with no
greater exertion, or, in some cases, with even less expenditure of power, thin
hitherto.
The essence of our invention consists in providing, in combination with each
driving crank, a stationary eccentric, the latter being so arranged as to vary or
control the.operative length of the crank in such a way that a greater leverage on
the down-stroke can be obtained than during the up-stroke.
The invention will be understood from the following description, reference being
had to the accompanying drawings, in which,
Figure 1 is a front view of our driving gear ;
Figure 2 a plan; and
Figure 3 a detail view.
In these, A is part of the framework of the machine, B cranks rigidly attached
to the axle C, D blocks sliding on the cranks and carrying the treadles E.
In the drawings, these cranks are made hollow and of diamond section so as to
secure lightness and strength combined. The blocks D are coupled by means of
rods F to eccentric-straps G or their equivalent, which latter are mounted upon an
eccentric H (or disc mounted eccentrically) with or without ball bearings between
to reduce friction, and the said blocks are operated by-said eccentrics. The cranks
drive the axle C on which the chain wheel'l is mounted but the eccentrics H are
fixed to the frame A. The eccentrics can however be adjusted in any desired
position.
The mode of action is as follows:-
In driving the machine, the cranks will revolve on their axis in the ordinary way,
but owing to the eccentricity of the two centres, namely, the centres of the cranks B
and that of the eccentric H, the blocks that carry the treadles will slide up and
down on the cranks and thus will approach or recede from the centre on which the
cranks rotate, describing a path indicated by the dotted circle. It will be seen
therefore that on the down-stroke a greater leverage can be obtained than on the
up-stroke of the crank, the latter being practically a dead point so far as its
influence in propelling the cycle is concerned.
We have described one way in which our invention may be carried into effect,
but it is obvious that alterations may be made in the construction and arrangement
of the various parts without departing from the invention. Thus, instead of forming
the cranks of a hollow diamond section, they may be made of any other suitable.
section or solid, or as an alternative the crauks may be slotted, and the sliding block
which carries the treadle adapted to slide in these slots.
Having now particularly described and ascertained the nature of our said inveu-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. The improvements in the driving gear for cycles, which consist in providing
in combination with each driving crank, a stationary eccentric or disc mounted
eccentrically, and so arranged as to vary or control the operative length of the

page_text: crank in such a way that a greater leverage on the down-stroke can be obtained
than during the up-stroke of the crank substantially as described.
2. In driving gears for cycles, the combination with the driving axle and cranks
rigidly attached thereto, of treadles mounted on and adapted to slide on the cranks
instead of being fixed thereto by nuts as formerly, and mechanism such as the
eccentric disc H and eccentric straps G for automatically varying the position of
the treadles radially on the cranks, whereby a greater leverage can be obtained on
the down-stroke than during the up-stroke of the crank, substantially as and for the
purpose described.
3. The combined arrangement and construction of parts, forming an improved
driving gear for cycles with variable leverage (long on the down-stroke of the
crank and short on the up-stroke) substantially as herein described and illustrated.
Dated this 26th day of February 1895.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham, and London, Patent Agents.