Improvements in Driving Chains and Wheels.
Year: 1891

page_text: Date of Application, 9th Mar., 1891
Complete Specification Left, 17th Aug., 1891-Accepted, 19th Sept., 1891
PROVISIONAL SPECIFICATION.
Improvements in Driving Chains and Wheels.
I, HERBERT GUTHRIE of Albert Road, Levenshulme near Manchester,
Engineer do hereby declare the nature of this invention to be as follows, that
is to say:
My invention mainly consists of improvements to that kind of chain gearing
known as driving chain gear and includes that used in driving cycles and pertains to
the chains, the wheels, and the mode of manufacture.
In the matter of chains preferably I would employ what are known as link-chains
in contradistinction to what are known as block-chains.
That is to say I prefer each part between pin and pin to drive cogs or teeth, or
to be driven by cogs or teeth. Nevertheless the principles involved in my invention
are partly but not so perfectly applicable to block-chains or chains where the block
links only touch the teeth and the links joining the blocks together do not touch the
driving or driven surface but serve only to connect the blocks together. So far
driving chains have been made with the driving head of a cylindrical form concentric
with the pin or thereabouts so that the actual driving surface has not been more
than a line along the cylinder until that cylindrical part got worn flat. The first
point in my invention is to make the ends of the links with a large flat surface.
And further that such surface should be at such an angle with the pitch or centre
line of the chain as may render a standard form of link suitable for wheels with
any number of teeth. That is to say, my links have a very small cylindrical portion
concentric with the pin or nearly so on the centre of the head on either side of the
pitch line and the flat surface forms a tangent to that cylindrical part so that the
driving surface is always on the one side only of the pitch line. The angle of this
tangential surface with the pitch line will vary somewhat according to the smallest
number of teeth which may be decided upon as the minimum sized wheel it may be
advisable to adopt. Thus should an eight tooth wheel be decided as the minimum
then the angle of the tangential surface with the pitch line would be approximately
45 degrees, whereas should a six tooth wheel be decided as the minimum the angle
of the tangential surface with the pitch line would be approximately 30 degrees.
The teeth of all larger wheels are made at the same angle with the pitch line so
that the driving or driven surface of the teeth will present a bed sufficient to form
an area of contact over the whole tangential surface of the link.
In the matter of wheels, as already intimated the wheels have teeth whose driving
or driven surface form a constant angle with the pitch line of the link working
with them, and further, the distance from tooth to tooth should be approximately
such as will just admit the link and no more and so secure the maximum thickness
of tooth together with maximum strength and endurance. These wheels do not
essentially require a rim of sufficiently large diameter to form a bed for the links
to lie on while doing work. But on the contrary it is one of the essential elements
of the invention that, while doing work, the tangential surface only of the links
touch the wheel and are quite free and apart from the rim. Further, and this is
one of the essential elements of the invention, that under the conditions herein before
described several or many links and teeth on one wheel do work; for, the angle of
the touching surface of link and tooth being obtuse to the line of pull or tension
it necessarily follows that the link will have a tendency to slip off; but, this is
prevented by the next link and this link again by the next and so on until all the
pull or work is absorbed. By this system the first tooth engaging with the pulling
chain receives the head of the link by an almost direct laying down of surface
on surface practically without any sliding motion whatever and as it turns round

page_text: with the wheel and deflects the link more and more from the straight line it takes
more and more duty until the next tooth comes into touch, after this the first
mentioned tooth is gradually relieved of its duty as more and more teeth come into
gear until at some point less than a semi-circle froin first engagement the first link
mentioned is entirely freed from duty and ready quietly to lift off without friction
or rubbing as soon as it arrives at the point for so doing. Although the above
principle mainly depends upon dead pressures in the transmission of the power it
nevertheless depends to some extent upon friction: so that, should the first link
take so much duty due to the angle of the duty surface with the line of tension
it will do so much more duty due to the frictional resistance to slip off.
One of the objects and great advantages of this invention is the fact that chains
and wheels so constructed are self adjusting in pitch, and work as truly when well
worn as when new. Thus should the wheels be made to accurately fit the chain
when new but with the teeth longer than then necessary, as the chain stretches with
wear the area of contact will automatically rise on the tooth owing to the angularity
of the contact surface inclining the chain to slip off. The wheel thus practically
assumes a larger pitch diameter as the pitch line is not fixed but is regulated by the
pitch of the link working on it. And a still further advantage of this invention is;
that, with an automatically adjustable pitch diameter as above described any little
irregularity of manufacture in either pitch or length of chain or teeth each link and
tooth will separately automatically adjust themselves and do fair duty. And yet
another advantage over many kinds of driving block chains now offered and used
for that purpose is the fact of the above invention precluding much slip in the case
of a reverse of motion. For, where the driving wheel is made larger than the pitch
of the chain working on it and where (as is necessary under such circumstances)
the space from tooth to tooth is considerably more than is necessary for the housing
of the block, in which case the slip may possibly be as much as the total length of
the block and equal to the stretch of many links according to the number of teeth
in the wheel, while the slip in my chain can never be more than the stretch of one
link or thereabouts. And there are yet advantages in my invention as applied to the
link chains I prefer, for, if each element of the chain does work in driving the wheel
instead of every alternate element (as in the block chain) there are therefore
practically double the number of teeth to the same sized wheel. And yet each of
those teeth are thicker and stronger than those ordinarily used with block chains.
With double the number of teeth there must be smoother working and more
regularity.
Further, in the matter of wheels. The wheels of my invention beyond the
peculiarity of outline and tooth formation applicable to wheels of otherwise ordinary
construction, I prefer to form my rims and teeth by stamping them cold out of
common sheet steel as hard as can be worked or of good soft steel capable of
hardening. These rings may be used either direct as punchings or be further trued
up by machining. Each wheel may be constructed of several rings laid side by
side either with teeth together or at half pitch (according as the links of the chain
may be arranged) and firmly riveted together with suitable lugs or recesses for
securing to the arms and or boss. By this means a cheap, perfect and easily
renewable rim and teeth is secured.
01 M1 1001
HERBERT GUTHRIE.
COMPLETE SPECIFICATION.
Improvements in Driving Chains and Wheels.
I, HERBERT GUTHRIE, of Albert Road, Levenshulme, near Manchester,
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 :-
This invention mainly consists of improvements in that kind of chain gearin

page_text: known as driving chain gear, the chief object of my improvements being to obtain
increased driving and wearing surface without increasing the diameter of the chain
wheels or materially increasing the weights of the parts.
Preferably I would employ what are known as link chains in contradistinction
to what are known as block chains; that is to say, I prefer each part between pin
and pin to drive cogs or teeth, or to be driven by cogs or teeth. Nevertheless the
principles involved in my invention are partly, but not so perfectly applicable to
block chains or chains where the block links only touch the teeth and the links
joining the blocks together do not touch the driving or driven surface, but serve
only to connect the blocks together.
Hitherto driving chains have been made with the driving head of a cylindrical
form concentric with the pin or thereabouts so that the actual driving surface has
not been more than a line along the cylinder until that cylindrical part got
worn flat.
The
The first point in my invention is to make the ends of the links with a large flat
surface, and further, that such surface should be at such an angle with the pitch or
centre line of the chain as may render a standard form of link suitable for wheels
with any number of teeth; that is to say, my links have a very small cylindrical
portion concentric with the pin or nearly so on the centre of the head on either
side of the pitch line and the flat surface forms a tangent to that cylindrical part
so that the driving surface is always on the one side only of the pitch line.
angle of this tangential surface with the pitch line will vary somewhat according
to the smallest number of teeth which may be decided upon as the minimum sized
wheel it may be admissible to adopt. Thus should an eight toothed wheel be
decided upon as the minimum then the angle of the tangential surface with the
pitch line would be approximately 45 degrees, whereas should a six tooth wheel be
decided as the minimum the angle of the tangential surface with the pitch line
would be approximately 30 degrees. The teeth of all larger wheels are made at
the same angle with the pitch line so that the driving or driven surface of the teeth
will present a bed sufficient to form an area of contact over the whole tangential
surface of the link.
In the matter of wheels, as already intimated, the wheels have teeth whose
driving or driven surface form a constant angle with the pitch line of the link
working with them, and further, the distance from tooth to tooth should be
approximately such as will just admit the link and no more, and so secure the
maximum thickness of tooth together with maximum strength and endurance.
These wheels do not essentially require a rim of sufficiently large diameter to form
a bed for the link to lie on while doing work; but on the contrary it is one of the
essential elements of the invention that, while doing work, the tangential surface
only of the links touch the wheel and are quite free and apart from the rim.
Further, and this is also one of the essential elements of the invention, that under
the conditions hereinbefore described, the work is done simultaneously by several
links and teeth on the same wheel; for, the angle of the touching surface of link
and tooth being obtuse to the line of pull or tension it necessarily follows that the
link will have a tendency to slip off; but, this is prevented by the next link, and
this link again by the next, and so on until all the pull or work is absorbed. By
this system (in the case of the chain lapping on the driving wheel) the first tooth
engaging with the pulling chain (counting from the free portion of the said pulling
chain) receives the head of the link by an almost direct laying down of surface on
surface practically without any sliding motion whatever and as it turns round with
the wheel and deflects the link more and more from the straight line it takes more
and more duty until the next tooth comes into touch, after this the first mentioned
tooth is gradually relieved of its duty as more and more teeth come into gear
until, at some point less than a semicircle from first engagement, the first link
mentioned is entirely freed from duty and ready to quietly lift off without friction
or rubbing as soon as it arrives at the proper point.

page_text: Although the above principle mainly depends upon dead pressures in the trans-
mission of the power it nevertheless depends to Fome extent upon friction; so
that should the first link take so much duty due to the angle of the working
surface with the line of tension, it will do so much more duty due to the
frictional resistance to its slipping off.
One of the objects of and great advantages obtained by this invention is that
chains and wheels so constructed are self adjusting in pitch, and work as truly
when well worn as when new. Thus should the wheels be made to accurately
fit the chain when new but with the teeth longer than then necessary, as the
chain stretches with wear the area of contact will automatically rise on the tooth
owing to the angularity of the contact surface inclining the chain to slip off.
The wheel practically assumes a larger pitch diameter as the pitch line is not
fixed but is regulated by the pitch of the link working on it; and a still further
advantage of this invention is that, with an automatically adjustable pitch
diameter as above described in spite of any little irregularity of manufacture in
either pitch or length of chain or teeth, each link and tooth will separately
automatically adjust themselves and do fair duty. And yet another advantage
over many kinds of driving block chains now offered and used for that purpose
is the fact of this invention precluding much slip in case of a reverse of motion,
for, where the driving wheel is made larger than the pitch of the chain working
on it and where (as is necessary under such circumstances) the space from tooth
to tooth is considerably more than is necessary for the housing of the block,
then the slip may possibly be as much as the total length of the block and equal
to the stretch of many links according to the number of teeth in the wheel; while
the slip in my chain can never be more than the stretch of one link or there-
abouts. There are yet advantages in my invention as applied to the link chains
I prefer, for, if each element of the chain does work in driving the wheel instead
of every alternate element (as in the block chain) there are therefore practically
double the number of teeth to the same sized wheel; and yet each of those teeth
is thicker and stronger than the tooth ordinarily used with block chains.
double the number of teeth there must be smoother working and more regularity.
Further, in the matter of wheels, the wheels of my invention beyond the
peculiarity of outline and tooth formation, applicable to wheels of otherwise
ordinary construction, I prefer to form my rims and teeth by stamping them, cold,
out of common sheet steel as hard as can be worked or of good soft steel capable
of being hardened. These rings may be used either direct as punchings or be
further trued up by machining. Each wheel may be constructed of several rings
or plates laid side by side either with the teeth together or at half pitch
(according as the links of the chain may be arranged) and firmly rivetted or
otherwise secured together, by this means a cheap, perfect, and easily renewable
rim and teeth is obtained.
With
And in order that my invention may be fully understood and readily carried into
effect I will describe the accompanying sheet of drawings reference being had to
the figures and letters marked thercon.
Fig. 1 1 is a side view of a chain and two chain wheels made according to my
invention.
Fig. 2 is an edge view of part of the chain.
Fig. 3 is an edge view of one of the chain wheels Fig. 14 or 1B and
Fig. 4 is an edge view of a double chain wheel.
Referring to the drawings-A B designate the two chain wheels and C_ the
chain, d d are the large flat tangential surfaces of the link heads placed at such an
angle with the pitch line E F as to ensure their slipping up the teeth of the wheel
on being pulled. gg are one set of wheel teeth the driving or driven surfaces of
which are set at a similar angle to the pitch line as the tangential surfaces of the
link heads and of a distance apart exactly to fit the link heads and without the
latter necessarily touching the rim of the wheel, and are the intermediate

page_text: teeth by which in conjunction with the teeth g g both the elements of the
chain Care caused to do driving duty and a perfect contact of link head surface
with tooth surface is effected.
Fig. 1 shows the chain C and wheel A when both are new and when no slip or
backlash can occur on the reversal of motion. Fig. 1B shows the chain C and
wheel B when much worn but still in perfect harmony of pitch and the driving and
driven surfaces in perfect contact, the space i representing the maximum amount
of slip or backlash possible under any circumstances. The peculiar angle of the
working or bearing surfaces above referred to constitutes, by the tendency of the
links to slip off the teeth, the automatic pitch adjustment; whereby, when new,
the lower part of the teeth come into action, and when old, the upper part or
tip, thus giving the wheel a longer life as well as a constant maintenance of
pitch. The teeth g g or hh may be alternated any number of times and cach
set made of any number of laminated rings or plates and composed of punchings
or cuttings from sheet material or forged or cast or made in any number of parts
as may be convenient. For example in Fig. 4 is shown a double chain wheel A¹
in this case composed of eight plates.
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 driving chain having large flat tangential working surfaces at each link
head and made at such an angle as to ensure said link heads mounting the chain
wheel tooth surface when the chain is pulled and so producing an automatic pitch
adjustment bringing many following links into gear with the chain wheel teeth at
the same time substantially as herein before described.
2. A chain wheel with intermediate or alternating teeth having large flat
working surfaces at such an angle as will ensure the chain links mounting them on
being brought into tension and so producing an automatic pitch adjustment bringing
many following teeth into gear with the chain t the same time substantially as
hereinbefore described.
3. The combination with a chain wheel having in addition to the ordinary teeth
intermediate or alternating teeth, of a chain the link heads of which have large
flat tangential working surfaces formed to fit on both the ordinary and intermediate
teeth of said wheel substantially as herein set forth.
4. A chain gear wheel constructed of a series of laminated rings or plates
substantially as herein before described and as illustrated by the drawings annexed.
Dated this 14th day of August 1891.
H. B. BARLOW,
17, St. Ann's Square, Manchester, Agent for Applicant.