An Improved Sprocket or Chain Wheel for the Driving Gear of Oycles, and the like.
Year: 1896

page_text: Date of Application, 17th Nov., 1896
Complete Specification Left, 17th Aug., 1897-Accepted, 18th Sept., 1897
An Improved Sprocket or Chain Wheel for the Driving Gear of
Oycles, and the like.
A communication by THEODOR LIEBERKNECHT, of No. 9 am Bahnhof Hohenstein-
Ernsttbal, in the Kingdom of Saxony, in the Empire of Germany,
Manufacturer.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E. of The Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool and 6 Bank Street, Manchester, both in
the County of Lancaster, 118 New Street, Birmingham in the County of Warwick,
and 322 High Holborn in the County of Middlesex, Civil Engineer, do hereby
declare the nature of this invention to be as follows:-
Experience has shown that a drawback exists in the driving chains of bicycles and
the like, which consists in a stretching of the links of the chain. This stretching or
extension of the links of the chain takes place to a comparatively considerable extent,
more particularly at the cominencement of its use, and has the highly deleterious
consequence of causing the links of the chain very soon to no longer coincide with
the divisions of the driving sprocket wheel, and accordingly all the links of the portion
of chain at the moment stretched over the sprocket wheel do not regularly engage
the latter as they actually should do, but always only a single link actually engages
correctly and rests on the wheel rim, whilst the remainder assume a wrong position
to the teeth. The whole power must therefore be mainly taken by a single tooth
and a single link of the chain, considerably accelerating the wear both of the chain
wheel and the chain, and also rendering the driving itself more difficult.
This invention relates to an arrangement whereby it is possible, when the chain is
stretched to any extent, to bring the sprocket again into coincidence with the
extended chain links in such a way that all the chain links at the moment embracing
the driving wheel shall come quite regularly into engagement with it and bear upon
it, and thereby cach tooth and each link of the chain only absorb a suitable fraction
of the driving power, or convey such, so that any slipping between the chain and the
wheel is avoided.
The arrangement whereby this is rendered possible consists in such a forination of
the sprocket wheel that those parts of the wheel rim which forms the support for the
chain liuks, rollers or bars may be adjusted to a larger circle so that the wheel then
works with a greater pitch. According to the kind of chain employed different parts
of the wheel rim are made adjustable.
In the accompanying drawings, three forms of construction are shown. In the
arrangement shown in Figure 1 in elevation and in Figure 2 in cross section, the parts of
the wheel rim lying between the actual teeth are alone adjustable so that the wheel
only undergoes an extension of its diameter at these places. With the chject of
rendering it adjustable, the parts of the wheel rim lying between the actual teeth a
consist of independent pieces b which fit in grooves or recesses in the wheel disc c
and may all be adjusted outwards in common and simultaneously.

page_text: A ring d provided ou one face with a spiral groove or screw thread, serves for this
common and simultaneous adjustment, the movable wheel-rim-parts b being
arranged to engage in the spiral groove or thread of the ring d by means of one or
more correspondingly bevelled or inclined pins or ridges e. The ring d fits in a
concentric groove in the wheel disc c so that hy turning the ring d to the right or
left, the various wheel-rim-parts b may be moved, in common, and simultaneously
either outwards or inwards. Several rim parts somewhat projected outwards are
shown in dotted lines at 6¹.
With such an adjustment the supporting places for the chain links are caused to
lie in a larger circular section, so that the wheel works then with a correspondingly
larger pitch. Such a pitch may be obtained by means of this arrangement as
corresponds to the stretching of the links of the chain which has taken place.
A key g, shown in dotted lines in Figure 1, may be employed for turning the
ring d, which key is inserted on two pins mounted diametrically opposite one
another on the ring d. The ring d after adjustment, is fixed by means of a clamp
ring i capable of being acrowed fast on to the wheel disc, in order to prevent an
undesired turning of the said ring in consequence of jolts or shocks.
It may also be pointed out that the upper half of Figure 1 shows the chain wheel
with the rings d and i removed.
In the modification shown in Figure 3 in elevation and cross section, each
adjustable piece b of the wheel rim includes also a half tooth so that the part of
the chain bearing attached to the tooth is adjusted with the movable picce.
In this case also, an enlargement of the pitch of the wheel takes place by the
extension or contraction of the pieces b and from the foregoing it is apparent without
further explanation that by means of the screw ring d the pitch may be increased to
correspond to the gradual stretching of the chain.
In the form of construction shown, the adjustable wheel-rim-parts only expand half
of the piece between each two teeth, but the working is in no wise affected
thereby.
The two forms of construction bereinbefore mentioned are more particularly suited
for so called block chains, such as shown in Figure 5. Where roller chains,
Figure 6, are used, a form of construction is recommended for the chain wheel, such
as is shown in Figure 4 in elevation and cross section. In this modification, ench
adjustable piece b includes in addition to the actual bearing for the roller, a
piece of each of the two adjacent teeth so that any outward adjustment of the
support piece 6 involves a direct increase of the pitch of the teeth and the latter
may thus be brought at any time into coincidence with the stretching of the links of
the chain.
ليمد
1000
COMPLETE SPECIFICATION.
An Improved Sprocket or Chain Wheel for the Driving Gear of
Cycles, and the like.
A communication by THEODOR LIEBERKNECHT, of No. 9 am Bahnhof Hohenstein
Ernstthal, in the Kingdom of Saxony, in the Empire of Germany,
Manufacturer.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of The Agency for Foreign
Patent Solicitors, 0 Lord Street, Liverpool, and 6, Bank Street, Manchester, both in
the County of Lancaster, 118 New Street, Birmingham in the County of Warwick

page_text: and 322 High Holborn in the County of Middlesex, Civil Engineer, do hereby
declare the nature of this invention and in what manner the same is to bo
performed, to be particularly described and ascertained in and by the following
statement
Experience has shown that a drawback exists in the driving chains of bicycles and
the like, which consists in a stretching of the links of the chain. This stretching or
extension of the links of the chain takes place to a comparatively considerable
extent, more particularly at the cominencement of its use, and has the highly
deleterious consequence of causing the links of the chain very soon to no longer
coincide with the divisions of the driving sprocket wheel, and accordingly all the
links of the portion of chain at the moment stretched over the sprocket wheel do not
regularly engage the latter as they actually should do, but always only a single link
actually engages correctly and rests on the wheel rim, whilst the remainder assume n
wrong position to the teeth. The whole power must therefore be mainly taken by a
single tooth and a single link of the chain, considerably accelerating the wear
both of the chain wheel and the chain, and also rendering the driving itself more
difficult.
This invention relates to an arrangement whereby it is possible, when the chain is
stretched to any extent, to bring the sprocket again into coincidence with the
extended chain links in such a way that all the chain links at the moment embracing
the driving wheel shall come quite regularly into engagement with it and bear upon
it, and thereby each tooth and each link of the chain only absorb a suitable fraction
of the driving power, or convey such, so that any slipping between the chain and the
wheel is avoided.
The arrangement whereby this is rendered possible consists in such a formation of
the sprocket wheel that those parts of the wheel rim which form the support for the
chain links, rollers or bars may be adjusted to a larger circle so that the wheel then
works with a greater pitch. According to the kind of chain employed different parts
of the wheel rim are made adjustable.
In the drawings accompanying the Provisional Specification, three forms of
construction are shown. In the arrangement shown in Figure 1 in elevation and in
Figure 2 in cross section, the parts of the wheel rim lying between the actual teeth
are alone adjustable so that the wheel only undergoes an extension of its diameter at
these places. With the object of rendering it adjustable, the parts of the wheel rim
lying between the actual teeth a consist of independent pieces b which fit in grooves
or recesses in the wheel disc c and may all be adjusted outwards in common and
simultaneously.
A ring d, provided on one face with a spiral groove or screw thread, serves for this
common and simultaneous adjustment, the movable wheel-rim-parts b being arranged
to engage in the spiral groove or thread of the ring d by means of one or more
correspondingly bevelled or inclined pius or ridges e. The ring d fits in a concentric
groove in the wheel disc c so that by turning the ring d to the right or left, the
various wheel-rim-parts b may be moved, in common, and simultaneously either
outwards or inwards. Several rin parts somewhat projected outwards are shown in
dotted lines at b¹.
With such an adjustment, the supporting places for the chain links are caused to
lie in a larger circular section, so that the wheel works then with a correspondingly
larger pitch. Such a pitch may be obtained by means of this arrangement as
corresponds to the stretching of the links of the chain which has taken place.
A key g, shown in dotted lines in Figure 1, may be employed for turning the
ring d, which key is inserted on two pins h mounted diametrically opposite one
another on the ring d. The ring d after adjustment, is fixed by means of a clamp
ring i capable of being screwed fast on to the wheel disc, in order to prevent an
undesired turning of the said ring in consequence of jolts or shocks.
It may also be pointed out, that the upper half of Figure 1 shows the chain wheel
with the rings d and i removed.

page_text: In the modification shown in Figure 3 in elevation and cross section, each
adjustable piece b of the wheel rim includes also a half tooth k so that the part of the
chain bearing attached to the tooth is adjusted with the movable piece. In this case
also, an enlargement of the pitch of the wheel takes place by the extension or
contraction of the pieces b and from the foregoing it is apparent without further
explanation that by means of the screw ring d the pitch may be increased to
correspond to the gradual stretching of the chain.
In the form of construction shown, the adjustable wheel-rim-parts only expand
half of the piece between each two teeth, but the working is in no wise affected
thereby.
The two forms of construction herein before mentioned are more particularly suited
for so called block chains, such as shown in Figure 5. Where roller chains, Figure 6,
are used, a form of construction is recommended for the chain wheel, such as is shown
in Figure 4 in elevation and cross section. In this modification, each adjustable
piece b includes in addition to the actual bearing for the roller, a piece k¹³ of each
of the two adjacent teeth so that any outward adjustment of the support pieco b
involves a direct increase of the pitch of the teeth and the latter may thus le Frought
at any time into coincidence with the stretching of the links of the chain.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is:-
1. A sprocket or chain wheel for cycles and the like, in which by the outward
adjustment of the parts (b) of the rim forming the support or bearing for the chain
links, either alone or together with adjacent parts of its teeth, the pitch of the wheel
may at any time be adjusted to meet the gradual stretching which takes place of the
links of the chain substantially as described.
2. In a sprocket or chain wheel such as described, having parts of its rim either
alone or together with adjacent parts of its teeth adapted to be outwardly adjusted
to increase the pitch, the arrangement for adjusting said bearing parts (b) in common
and simultaneously by means of a screw ring (d) substantially as described.
Dated this 16th day of August 1897.
WM. P. THOMPSON & Co.,
Agente.