Improvements in Chain Gearing.
Year: 1896

page_text: Date of Application, 4th Sept., 1896
Complete Specification Left, 2nd Nov., 1896-Accepted, 5th Dec., 1896
Improvements in Chain Gearing.
I, THOMAS JENNINGS, of Brookfield, Cork, Ireland, Merchant, Justice of the
Peace, do hereby declare the nature of this invention to be as follows:-
My invention relates to chain gearing and has for its object the provision of
means whereby the driving load on the chain is only upon the chain when the
latter is in or approximately in a straight line between the driving and driven
wheels and thus obviates the friction which exists in the usual methods of chain
driving by the movement of the articulated parts of the chain about their pivots
whilst travelling through a curved path, such as round the periphery of a driving
or driven wheel.
To carry my invention into effect I arrange the chain to run upon two loose or
idle wheels so as to extend it into a more or less stretched condition. These
wheels may be made with a smooth periphery without any teeth or recesses, and
are arranged so that the chain engages with the driving and driven wheels from
and to which the motion is transmitted, upon that portion of the chain which is
in or approximately in a straight line between the peripheries of the idle wheels
upon which it runs. The driving and driven wheels are provided with teeth or
other equivalent means to engage the chain.
In order to ensure the certain engagement of the chain with the driving and
driven wheels I prefer to arrange the idle wheels so that a line tangential to their
peripheries shall intersect the peripheries of the driving and driven wheels. I
may make the axis of either one or both of the idle wheels to be adjustable in
order to tighten the chain or to vary the number of teeth of the driving or driven
wheels engaged by the chain.
Ca
11800
Improvements in Chain Gearing.
THOMAS JENNINGS of Brookfield, Cork, Ireland, Merchant, Justice of the
Peace 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 i-
My invention relates to chain gearing and has for its object the provision of
means whereby the driving load on the chain is only upon that portion of the
chain which is in, or approximately in, a straight line between the driving and
driven wheels and thus the friction is obviated which exists in the usual methods of
chain driving by the movement of the articulated parts of the chain about their

page_text: pivots whilst travelling through a curved path such as round the periphery of a
driving or driven wheel.
To carry my invention into effect I arrange the chain to run upon two loose or
idle wheels so as to extend it into a more or less stretched condition. These wheels
may be made with a smooth periphery without any teeth or recesses and are
arranged so that the chain engages with the driving and driven wheels from and
to which the motion is transmitted upon that portion of the chain which is in, or
approximately in a straight line between the peripheries of the idle wheels upon
which it runs. The driving and driven wheels are provided with teeth or other
equivalent means to engage the chain.
In order to ensure the certain engagement of the chain with the driving and
driven wheels I prefer to arrange the idle wheels so that a line tangential to their
peripheries shall intersect the peripheries of the driving and driven wheels. I
may make the axis of either one or both of the idle wheels to be adjustable in
order to tighten the chain or to vary the number of teeth of the driving or driven
wheels engaged by the chain.
In order that my invention may be the better understood I will now proceed to
describe it in relation to the accompanying drawing hereunto aunexed reference
being had to the letters and figures marked thereon.
Like letters refer to like parts in the figures.
Figure 1 is a side elevation of my improved chain gearing.
Figure 2 is a view of my gear applied to a bicycle.
A A are the driving and driven chain wheels and B. B are the idle or carrying
wheels over which the chain C is stretched and adapted to run.
The idle wheels B. B. are made adjustable by being pivotably mounted on
bárs or supports D which are themselves pivotably inounted on the axle or on the
part supporting the axle. The supports D are provided with means to allow of
the adjustment of the idle wheels relative to the chain wheels to take up slack in
the chain and to ensure the proper engagement of the chain with the engaging
means on the chain wheels to a more or less extent as may be desired, such for
example as the number of teeth engaged and when the proper position of the idle
wheels has been obtained they can be maintained in position by clamping
with a screw bolt or other equivalent device passing through the slot E in the
support D.
In Figure 2 the gear is adapted to a bicycle and is substantially the same as
hereinbefore described the only difference being that the adjustment of the idle
wheels is effected by an adjustable stay F from the frame of the bicycle to each of
the supports D.
From the drawings it will be obvious that only that tooth or the two or three
teeth to which the chain is tangential engage the chain and thus the inechanical
efficiency of the gearing is greatly increased.
The idle wheels may if desired have flanges on each side thereof between which
the chain runs and may be brought down close to the peripheries of the chain
wheels in order to prevent the chain from disengagement with the chain wheels.
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:-
1st. In chain driving gear in combination a chain idle wheels supporting said
chain in a more or less stretched or extended condition and chain wheels adapted
to engage on the one side or part of the chain situated between the said idle
wheels.
2nd. In chain driving gear in combination a chain idle wheels supporting said
chain means for adjusting. said idle wheels in relation to one another and to the
chain wheels and chain wheels adapted to engage on one side or part of the chain
situated between the said idle wheels.

page_text: 3rd. In chain driving gear a chain, idle wheels carrying said chain and chain
wheels adapted to engage the chain only at that portion of the wheels where the
chain is tangential to the periphery of the said chain wheels.
Dated this 2nd day of November 1896.
FELL & JAMES,
1 Queen Victoria Street, London, E.C., Agents for the Applicant.