Improvements in Driving Cycles, Motor Cars, or other Machinery by Sprocket Wheels and Chains.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Driving Cycles, Motor Cars, or other Machinery by
Sprocket Wheels and Chains.
I, ANTHONY SPENCER BOWER, St. Neots, Hunts, Engineer, do hereby declare
the nature of this invention to be as follows:-
-
One part of this invention applies to such chains and sprocket wheels as already
exist, and to improve their action I take away the larger portion of the sprockets
or projections upon the wheels and in lieu thereof provide guiding pins which may
be screwed into the wheel rims. These pins are of the proper shape laterally to
guide each link into its proper place in so far as side motion is concerned so
that there is no possibility of the chain getting off the wheel. Longitudinally
along the rim of the wheel the dimensions of the pins are less than those of the
sprockets they replace, and so they do not receive any driving effort from or
impart any to the chain, and the necessity of pulling the chain off every sprocket
of the ordinary wheels is avoided.
It is well-known that when the least wear has taken place, it is only the sprocket
nearest the point where the chain leaves or comes upon the wheel which is ever
in gear or really driving or being driven, the links of the chain in contact with
the other sprocket, simply scrambling for a place, and in extreme cases actually
riding upon the tops of the sprockets. One sprocket in full gear is all that is
necessary. The pins which I use instead of the greater number of the present
sprockets may be provided with flanges near the rim of the wheel upon which the
links may rest and these flanges may be utilized to screw the pins out and so
virtually increase the diameter of the wheel and take up any slack which occurs
by reason of the wear of the chain links. In this manner a worn chain which is
badly out of gear may be put right again, and kept so, and the enormous wear
of the driving or driven sprockets which now obtains avoided.
or
one
In
Another part of my invention consists in almost entirely avoiding link wear
by causing the pins which join two side links together to roll upon the ends of
the adjoining links. The pins and the link ends being suitably rounded
or shaped to permit such action,
of them may be flat.
some cases the pin may take the form of a suitably formed projection
on each side of a central bar, and hollow links with suitably formed
ends may roll upon these projections. Knife-edges for one portion of a link to
vibrate upon another portion has already been devised but this is not a true rolling
motion at all and wear must take place just as wear takes place in the knife
edges of a balance. By my arrangement I allow the line of contact to vary
slightly from side to side and I so arrange the surfaces of contact that the thrust
of pin against link end is almost exactly normal at all times. Furthermore, I so
arrange the link ends which drive, or are driven by, the sprockets that they roll
themselves in and out of gear, and when a link passes over a sprocket it does so
without touching it, but by the action of the chain in conforming to the circum-

page_text: ference of the wheel the link end first comes into contact with the sprocket
and then takes up the strain previously existing upon the sprocket in front of it
so that the link end previously in contact with the latter sprocket is free to come
off the wheel without any pulling or snatching action. Similarly with the
driving sprocket wheel. A sprocket drives a link so long as the latter is in full
contact with the wheel. As soon as it begins to leave it, it releases itself by the
rolling action already referred to and allows the strain to gradually come upon the
sprocket behind it, and so a link coming into gear releases the one in front of it
which is in gear and a link coming out of gear puts the one behind it into gear.
With this new arrangement of chain I still do away with the greater portion
of the driving sprockets, and provide adjustable pins which are useful to take up
any actual stretch which might occur through undue strain, or virtual increase in
the length of each link by rusting action, as also to eliminate the minute wear
which might take place. These adjustable pins are also of service in getting a
wheel and chain exactly in gear at first starting.
E. EATON,
Agent for Applicant.
Improvements in Driving Cycles, Motor Cars, or other Machinery by
Sprocket Wheels and Chains.
ANTHONY SPENCER BOWER, Saint Neots, Hunts, Engineer, 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;-
One part of this invention applies to such chains & sprocket wheels as already
exist, & to improve their action I take away the larger portion of the sprockets
or projections upon the wheels, & in lieu thereof, provide guiding pins which
may be screwed into the wheel rims.
These pins are of the proper shape laterally to guide each chain link into its
proper place, in so far as side motion is concerned, so that there is no possibility
of the chain getting off the wheel.
Longitudinally, along the rim of the wheel the dimensions of the pins are
less than those of the sprokets they replace, & so they do not receive any driving
effort from, or impart any to, the chain, & the necessity of pulling the chain
off every sprocket of the ordinary wheels is avoided.
It is well known that when the least wear has taken place, it is only the sprocket
nearest the point where the chain leaves, or comes upon, the wheel, which is ever
in gear, or really driving or being driven, the links of the chain in contact with
the other sprockets simply scrambling for a place, & in extreme cases actually
riding upon the tops of the sprockets.
One sprocket in full gear is all that is necessary. The pins which I use instead
of the greater number of the present sprockets may be provided with flanges
near the rim of the wheel upon which the links may rest, & these flanges may be
utilised to screw the pins out and so virtually increase the diameter of the wheel,
& take up any slack which occurs by reason of the wear of the chain links.
In this manner a worn chain which is badly out of gear may be put right again,
& kept so; & the enormous wear of the driving, or driven sprockets, which
now obtains, avoided.
Another part of my invention consists in almost entirely avoiding link wear

page_text: by causing the pins, which join two side links together, to roll upon the ends of
the adjoining links.
The pips & the link ends being suitably rounded or shaped to permit such action.
In some cases the pin may take the form of a suitably formed projection on
each side of a central bar; & hollow links, with suitably formed ends, may roll
upon these projections.
Knife edges; for one portion of a link to vibrate upon another portion; has
already been devised but this is not a true rolling motion at all, and wear must
take place, just as wear takes place in the knife edges of a balance. By my
invention I allow the line of contact to vary slightly from side to side & I so
arrange the surfaces of contact that the thrust of pin against link end is almost
exactly normal at all times.
Furthermore I so arrange the link ends which drive, or are driven by, the
sprockets that they roll themselves in & out of gear, & when a link passes over
a sprocket, it does so without touching it, but by the action of the chain in con-
forming to the circumference of the wheel the link end first comes into contact
with the sprocket & then takes up the strain previously existing upon the sprocket
in front of it, so that the link end previously in contact with the latter sprocket
is free to come off the wheel without any pulling or snatching action.
Similarly with the driving sprocket wheel a sprocket drives a link so long as the
latter is in full contact with the wheel.
As soon as it begins to leave it, it releases itself by the rolling action already
referred to, & allows the strain to gradually come upon the sprocket behind it;
& so a link coming out of gear puts the one behind it into gear.
With this new arrangement of chain I still do away with the greater portion
of the driving sprockets, & provide adjustable pins which are useful to take up
any actual stretch which might occur through undue strain, or virtual increase
in the length of each link by rusting action as also to eliminate the minute wear
which might take place.
These adjustable pins are also of service in setting a wheel and chain exactly
in gear at first starting.
And in order that my invention may be fully understood & readily carried
into effect I will proceed to describe the accompanying sheet of drawings, reference
being had to the figures and letters marked thereon.
Fig. (1) is a section of a sprocket wheel & chain, the wheel being supposed to
be driven by the chain in the direction of the arrow. Fig. (2) is another section
of the same wheel & chain after they have moved a little farther round in the
direction of rotation. Fig. (3) is a plan of a small piece of chain similar to that
which is round the wheels.
Similar letters apply to similar parts.
The wheel is composed of fixed sprockets (a) & loose ones (b)
All of them have a nick (c) cut partly down them, such nick being sufficiently
broad to allow the pins (d) to enter.
The chain is composed of straps (e) drilled at each end to allow the pins (d) to
pass through, as also are the pieces (f) which serve to strengthen the ends of the
straps (e), and to provide a hard rolling surface for the rotating, or rolling,
pins (g) which pass through the side links (h) of the chain, & are firmly fixed
thereto. In order to do this effectively the pins (9) may be somewhat reduced
in size, as shown at (k), just before they pass through the side links (h) so that the
larger section thereof serves as a species of abutment to resist the riveting action
on the outside of the side links (h) when such a method of fastening is resorted
to.
By another method the pins (g) may be secured after passing through the side
links, by slipping over the ends a washer whose internal form is the same with
that of the external shape of the pin ends.
This washer is then forced to assume a circular form. and so cut into a nick or
groove in the pin ends and hold the latter fast, as fully shown at (l).

page_text: By another method a flat spring strip (m) is sprung into recesses (n) in the
pin ends & the same object is attained for the side links (h) cannot separate in
either case without shearing off a piece of metal.
The pins (d) are also utilised to keep the vibrating pins (9) from touching the
sides of the straps (e) at any time, & this is done by providing the pins (g) with a
small hole or cavity (o) into which the pins (7) may loosely fit after the fashion
of a wheel tooth in spur gearing.
In Fig. (1) it will be seen that a link or strap (e) is driving a sprocket (2) all
the others being out of contact with the exception of (a) which the chain has come
on to, but has not yet received any strain upon it.
The pin (d) has just reached the bottom of the nick (c), & when the wheel moves
further round as in Fig. (2) the strap end rolls itself upon the face of the
sprocket (a), and at the same time draws that strap end which was previously
driving the sprocket (a) away from it, & leaves it free to move off the wheel
when the proper time comes.
This drawing off action is also assisted by the rolling of the flat end of the
pin (g) upon the hardened curved surface of the piece (f).
In rig. (2) therefore (a) has become the driven sprocket, & (a) is released;
and in like manner (a) will be released & (a4) come into gear, & so on con-
tinuously. The amount by which one strap is pulled away from a sprocket is
regulated by moving the sprockets, or guiding pins (b), in or out, & in any wheel
& chain these dummy sprockets, or guides, are of great utility, as they serve to
put the wheel into proper pitch with the chain as the latter wears.
Such sprockets, as well as the real driving or driven ones, may also be made
with a certain amount of free motion circumferentially as shown by (a). In such
a case the sprocket may vibrate about a centre (2), & be moved in or out radially
by suitable mechanism.
The sprocket (4) should be kept against its driving, or driven face, by means
of a light spring (7).
By this method the slight friction caused by the minute movement of the chain
upon the wheel is practically eliminated.
In Figure (4) the pins (9) are rounded at the ends, and roll upon flat, or
approximately flat pieces (f) at the ends of the straps (e), & in this case it is
necessary to provide a recess in the piece (f) into which a projection on the pin (g)
may fit, or vibrate, or otherwise the pin (9) would slip down the surface of (f) when
the chain is passing round a wheel of small diameter, or rather of few teeth.
This method is not so good as the preceeding one, but it is necessary to mention
it, as one part of the merit of the invention consists in obtaining a true rolling
motion between one link and another.
In Fig. (5), a block (r) has pins (s) with recesses (t) formed with, or otherwise
firmly attached to the block, & upon each side of the blocks are side links (u) with
holes (v) at each end, such holes having a small projection (w) which may vibrate
within the recesses (t) aforesaid, and in this modification the side links partially
rotate about pins fixed on to, or in to, a block instead of their carrying pins to
vibrate inside a strap as in the first example.
The result is the same; as the blocks drive, or are driven by the chain and roll
themselves in, or out of gear, assisted by the rolling of the flat surface of the link
ends upon the rounded surface of the pins (s).
In this example, as in the first case, there is no tendency to slip, but the
projections, & recesses, are employed so that under no circumstances can there
be side friction of pin against link end...
Fig. (6) is an important modification for small chains such as, for example
cycle, or motor cars, chains.
In it there is a centre piece (A) with a species of four sided hole with rounded
ends formed in it at each end, & the side links (B) are formed in the same manner.
An oval shaped pin (C) passes through these holes, and so joins the various links

page_text: together. These pins (C) may be reduced to a circular section at each end, & a
circular washer may be riveted or otherwise fastened on the outside so that the
pins (C) cannot get out of the links (A) & (B) sideways.
In this manner it will be seen that the links (A) & (B) roll with their flat, or
approximately flat, ends upon the rounded ends, or sides, of the oval shaped
pins (C), and the same object as heretofore is obtained.
The rectangular holes are preferably made wider at that side of the chain which
is more remote from the wheel circumference so that under no conditions are
the sides of the said holes so much inclined to the vertical axes of the oval pins
as to induce slipping when the chain passes round the wheel.
The centre, & side links may be made of two or more, precisely similar flat
plates if so desired.
This modification is a somewhat simpler method of carrying out the spirit of
the invention which it will now be seen is to prevent rubbing action of link
upon link, & link upon sprocket & substitute therefor a true rolling action.
In Figure (2), if the wheel be supposed to be rotating in the reverse direction
to that shown by the arrow, and to drive the chain, it will be seen that
sprocket (a) is driving, but that in Figure (1) the chain has rolled itself out of
gear & allowed the strain to come upon (2) and so on continuously, & therefore
whether driving, or driven, the chain rolls itself in or out of gear as desired.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is —
(1) Adjusting the pitch of a chain wheel to that of the chain by means of
non-driving, but guiding, sprockets, such being movable radially inwards, or out-
wards, as desired.
(2) Causing the links, and pins, of a chain to roll upon one another without
rubbing action, and with extended rolling surfaces substantially as herein
described.
(3) Causing the links of a chain to roll themselves in, and out of, gear with the
chain wheel, and to draw out, or let into gear another link at the same time by the
rolling action of pin upon link, or link upon sprocket, or both combined, as herein
described and illustrated.
Datad this 25th day of January 1800