Improved Means for Adjusting the Driving Chains of Safety Bicycles, Tricycles, and other Velocipedes,
Year: 1892

page_text: Date of Application, 12th Feb., 1892
Complete Specification Left, 14th Sept., 1892-Accepted, 15th Oct., 1892
PROVISIONAL SPECIFICATION.
Improved Means for Adjusting the Driving Chains of Safety
Bicycles, Tricycles, and other Velocipedes,
I, ALFRED BLACKWELL, of No. 264 Icknield Street, Hockley, Birmingham,
Warwickshire, Cycle Manufacturer, do hereby declare the nature of this invention
to be as follows:-
This invention consists of the hereindescribed improved means for adjusting the
tension of the endless driving chains of safety bicycles, tricycles and other
velocipedes.
As an example I will describe my invention as applied to a safety bicycle.
In carrying out this invention the axle of the driving wheel which receives
motion from the crank axle by the endless chain is carried at the outer ends of two
short levers one at either side of the wheel which levers are jointed to two eyes on
the fork or frame of the bicycle, so that the levers and the axle carried thereby are
capable of being turned about the centre of these eyes as a fulcrum to bring the
said driving wheel axle either nearer to or farther from the driving crank axle and thus
either slacken or tighten the driving chain. The said short side levers are or may
be continued beyond the fulcrum and these continuations may be each jointed to
screws which pass through ears on the frame of the machine and are furnished
with adjusting and locking nuts so that by turning these nuts the said short side
levers are turned about their fulcrum and the tension of the driving chain can be
adjusted as required. Or the said adjusting screws may be jointed to the same
ends of the said short side levers as is the driving wheel axle. Or the said side
levers may be each provided with a spring catch or click so arranged that when the
side levers have been turned to obtain the proper tension on the driving chain the
said clicks engage with teeth formed on sectors fixed to the machine frame and
thus secure the said levers in the required position.
Dated this 11th day of February 1899
CHARLES BOSWORTH KETLEY,
Agent for the Applicant.
COMPLETE SPECIFICATION.
Improved Means for Adjusting the Driving Chains of Safety
Bicycles, Tricycles, and other Velocipedes.
1, ALFRED Blackwell, of No. 264 Icknield Street, Hockley, Birmingham,
Warwickshire, Cycle Manufacturer, 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 consists of the hereindescribed improved means for adjusting the
tension of the endless driving chains of safety bicycles, tricycles and other
velocipedes.
As an example I will describe my invention as applied to a safety bicycle and I
will refer to the accompanying drawings in which
Fig. 1 is a side elevation of part of the back fork or frame of a safety bicycle
and the axle and hub of the driving wheel and driving chain with my invention
applied;
Fig. 2 represents the same parts but shews the driving chain tightened up by my

page_text: Fig. 4 illustrates a modification of my invention and
Fig. 5 shews a further modification.
The same letters of reference indicate the same or corresponding parts in all the
figures of my drawings.
In carrying out this invention the axle A of the driving wheel (the hub and part
of the spokes of which are shewn and marked B) which receives motion from the
crank axle by the endless chain C (a part only of which is shewn on my drawings)
is carried at the outer ends d of two short levers D. Only one of these levers D
is shewn on my drawings but it is to be understood that there is one of these levers D
at one side of the wheel and the other lever D at the other side thereof. The
two levers Dare by bolts E jointed to corresponding eyes F on the fork or frame G
of the bicycle so that the levers D and the axle A carried thereby are capable
of being turned about the bolts E at the centre of these eyes F as a fulcrum
to bring the driving wheel axle A either nearer to or farther from the
driving crank axle and thus either slacken or tighten the driving chain C.
Fig. 1 shews the position of the driving wheel axle and levers Ď when the
levers are turned to their extreme position in one direction to make the chain C
slack, and Fig. 2 the position of the driving wheel axle and levers D when the
levers are turned to their extreme position in the other direction to tighten up the
chain C. The short side levers D may be continued at D¹ as shewn in Figs. 1
and 2 beyond the fulcrum E and these continuations D' may be each jointed to
screws H (one screw H for cach lever) which pass through ears I on the frame G
of the machine and are furnished with adjusting and locking nuts J'J' so that by
turning these nuts the short side levers D are turned about their fulcrum E and the
tension of the driving chain C can be adjusted as required and fixed at any
desired tension.
Or as shewn in Fig. 4 the adjusting screws H may be jointed to the same ends d
of the short side levers D as is the driving wheel axle A.
Or as shewn in Fig. 5 the adjusting screws H may be dispensed with and the
side levers D may each have a prolongation D provided with an ordinary spring
catch or click K so arranged that when the side levers D and their prolongations D'
have been turned to obtain the proper tension on the driving chain C the clicks K
engage with teeth / formed on two sectors L fixed respectively to the two sides of
the fork of the machine frame and thus secure the levers D in the required
position.
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 :-
The improved means for adjusting the tension of the driving chains of safety
bicycles tricycles and other velocipedes hereinbefore described and illustrated by
the accompanying drawings consisting of the combination and arrangement of the
two levers D jointed to the forked end of the machine frame and carrying the axle
of the driving wheel and the driving wheel between them and the screws H or clicks
or catches such as K for adjusting and fixing the levers D all arranged and acting
substantially as hereinbefore set forth and shewn.
Dated this 13th day of September 1892.