Improvements in and relating to Chain or Sprocket Wheels.
Year: 1892

page_text: Date of Application, 22nd Aug., 1892
Complete Specification Left. 19th June, 1893-Accepted, 12th Aug., 1893
PROVISIONAL SPECIFICATION.
Improvements in and relating to Chain or Sprocket Wheels.
IWALTER BIDDLES of 70 Curzon Street, Leicester in the County of
Leicester, Cycle Maker, do hereby declare the nature of this invention to be as
follows :-
My invention relates to improvements in chain or sprocket wheels, especially
applicable to velocipedes, the object being to take up the slack of the chain
Hitherto this has been
employed, caused by wear or stretching of the same.
accomplished by shortening the chain, i.e. taking out one or more links, or by
shifting the relative positions of the two chain or sprocket wheels or by a com-
bination of these two methods. But neither of these methods are entirely
satisfactory owing to the "pitch" of the chain varying as it stretches.
Now according to this invention I overcome this difficulty by constructing a
chain or sprocket wheel in the following manner:-1 cut or form slots or grooves
in the face of a wheel, radiating from the centre and terminating at the periphery.
Into these slots or grooves I fit pieces of metal, the outer ends of which are cut to
form teeth of the ordinary shape to gear with the chain. These pieces of metal
or elongated teeth being fitted into the said slots or grooves in such a manner as to
be free to slide to or from the centre. When all these pieces of metal are in their
respective slots or grooves and in their normal position, that is-when the outer or
tooth ends are just protruding sufficiently through the periphery of the wheel to
be capable of gearing with the chain,-I cut or form on the flat exposed faces of
the pieces of metal one or more helical grooves which are made to engage with
corresponding projections formed on the inner face of a plate or ring fitting over
them. As the plate or ring engages with the aforesaid pieces of metal or teeth it
will be obvious, that should the ring be turned independently of the wheel either
to the right or left, it will cause the teeth either to recede or project and thus vary
the pitch of the said teeth. The plate or ring may be locked in position after the
necessary adjustment has been made in any suitable manner.
Dated this 22nd day of August 1892.
ROBT. ED. PHILLIPS, M.I.M.E.,
Consulting Engineer and Patent Agent,
0, Chancery Lane, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Chain or Sprocket Wheels.
! WALTER BIDDLES, Cycle Maker 62 Curzon Street, Leicester 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:-
The invention which I claim consists of an arrangement whereby a chain-wheel
and chain may be kept a perfect fit by means of an expanding chain-wheel, which
can be adjusted to suit the pitch of the chain as the latter stretches or wears
longer in use. The means I propose to use is a wheel-frame or circular disc of
metal with any desired number of grooves (or raised projections to be used as
slides) cut on its surface in a direct line from the centre with a corresponding
number of sliding teeth fitted into the aforesaid grooves, or on to the slides (as the
case may be) such sliding teeth to be capable of adjustment to or from the centre

page_text: of wheel-frame. The method of fixing the aforesaid wheel-frame to the axle or
hub may be any of those usually adopted for ordinary chain wheels.
As will be readily seen, when the sliding-teeth are adjusted further from the
centre the diameter of the pitch-line will be increased and consequently in a pro-
portionate degree the circumference and length of pitch of the teeth will be
increased and may be adjusted to any desired pitch.
The means of adjustment may be of various forms but I do not consider the
means of adjustment as an essential feature of my invention and claim to use any
method which I may find most suitable, either by set screws small eccentrics, or
cams, used in any form found desirable; either to adjust each tooth separately or
all of them simultaneously.
The method however which I prefer is by means of an adjusting plate with
a scroll or worm cut upon its surface and with a corresponding worm or scroll
cut upon the surface of the sliding teeth; the two scrolls or worms when placed
together in position to inter-lock, when by turning the adjusting plate (which
is secured centrally) to the right or left, the teeth will be extended from or
drawn towards the centre; when adjusted as desired the scroll and teeth may be
locked up firm either by means of small screws, or by one large locknut, which
will press upon the scroll or adjusting plate this in turn to press upon the teeth in
the grooves or on the slides as the case may be.
In the accompanying drawings:-
-
Fig. 1 shows wheel-frame fitted with a complete set of sliding teeth, one of
which (A) is partly withdrawn to show the manner of adjustment.
Fig. 2 shows the metal adjusting plate or scroll reversed, which, when laid on the
teeth as per Fig. 1 interlocks with them when by turning to the right or left the
teeth are forced outwards from, or inwards to, the centre as required.
Fig. 3 shows wheel complete with scroll in position when by placing a wrench or
spanner on the hexagon head which is on the outer surface of adjusting plate the
said adjusting plate or scroll may be turned for adjusting as required.
Fig. 4 shows another of the many methods of adjustments; but, the screws may
also be used in the same direction as the sliding teeth (and may be a continuation
of them if required) viz. :-in a direct line from the centre.
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:-
(1.) A means of securing a perfect fit at any or all times between a chain and
the wheels upon or around which it moves, and to counteract the effect of the
stretching or wearing of chains which are found to lengthen in use, when, after
such stretching or lengthening has taken place the chain is found not to fit the
wheel perfectly but tries to allow for its increased length by riding up the teeth at
a larger distance from the centre thereby greatly increasing the amount of
friction.
(2.) Such means are secured by a disc of metal, or wheel-frame, as herein
described, with a set of grooves or slides on its surface in a straight line from the
centre and with a set of teeth (called sliding-teeth) fixed in or on the same capable
of adjustment to or from the centre.
(3) The means of adjustment (which I do not consider or claim to be the
essential part of this invention) which I prefer is the scroll simultaneous adjust-
ment as described, but, I claim to use any other means which I may find suitable.
Dated this 17th day of June 1893.
WALTER BIDDLES,
Applicant.