Improvements in Chain Gearing.
Year: 1895

page_text: Date of Application, 6th Nov., 1895
Complete Specification Left, 1st Aug., 1896-Accepted, 5th Sept., 1896
Improvements in Chain Gearing.
I EDGAR WILLIAM TIMMIS of 2 Great George Street Westminster
London S.W., Engineer do hereby declare the nature of this invention to be as
follows:-
:―
The object of my invention is to do away with friction as far as possible in the
case of chain gearing; that is to say, in the conveying of power from one place
to another by means of a chain and gear or sprocket wheel or wheels.
To this end I cause the power to be conveyed from one link to another (it is
supposed to be known that a chain is composed of links of one form or another)
by means of a knife edge, or practically a knife edge, which is part of one link,
bearing on a suitable bearing which is part of the other. I may use two or more
knife edges instead of one, and two or more bearings instead of one. The bearings
may be flat or concave or of any suitable form in to or on to which a knife edge
or knife edge or knife edges is or are capable of bearing.
Hence it is so arranged that as the links pass on to or off the gear or sprocket
wheel or wheels they each severally turn with respect to one another on the knife
edges only, whether the knife edge or edges forms or form part of that link which
is turning or not. Each alternate link may be provided with two knife edges or
with two bearings for knife edges (as herein before described) or with a knife edge
and bearing each, in the former case the links might each be symmetrical and in
the latter might all be alike, or in various modifications or combinations of these
arrangements, or a series of links may be arranged in any of these ways, that is to
say, a set of say two, three, or more may be alike and of another form, and so on
throughout the length of the chain.
It is also, or may be, arranged that the links convey or receive the power to or
from the gear or sprocket wheel or wheels by bearing with their knife edges on
the teeth of the gear or sprocket wheel or wheels, so that when the links leave or
pass on to the gear or sprocket wheel or wheels they (the links) turn on their
knife edges only with respect to the gear or sprocket wheel or wheels. The same
knife edge or edges may or may not be used for this purpose as is or are used to
convey or receive the power to or from one link to another. In the latter case
the position of knife edge or edges and bearing or bearings may be reversed,
that is to say the knife edge or edges may form part of the gear or sprocket wheel
or wheels and the bearing or bearings form part of the links, or the knife edges and
bearings may exist on both.
The use of knife edges and their bearings is well known as a means of
minimising friction in the moving parts of weighing machines and balances and
hence from the above description the advantages of the adaptation of such to the
chains of bicycles &c. or other machinery where the minimising of friction is
important, are apparent.
Rollers may also be used in place of knife edges in any of the above arrange-
ments, on the gear wheel or wheels, or on the links, some or all, or on both gear
wheel or wheels and links. The rollers may also be used in connection with any
of the above arrangements of knife edges, some of the knife edges being replaced
by rollers or a combination of knife edges and rollers.

page_text: where rollers are used I may arrange them so that one or more roller surface
or surfaces bears or bear against one or more roller surface or surfaces.
Dated this 6th day of November 1895.
I, EDGAR WILLIAM TIMMIS of 2 Great George Street, Westminster S. W.,
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 :--
The object of my invention is to do away with friction as far as possible in the
case of chain gearing; that is to say, in the conveying of power from one place to
another by means of a chain and gear or sprocket wheel or wheels.
To this end I cause the power to be conveyed from one link to another (it is
supposed to be known that a chain is composed of links of one form or another)
by means of a knife edge, or practically a knife edge, which is part of one link,
bearing on a suitable bearing which is part of the other. I
knife edges instead of one, and two or more bearings instead of one.
may use two or more
The bearings
may be flat or concave or of any suitable form into or onto which a knife edge
or knife edges is or are capable of bearing.
Hence it is so arranged that as the links pass onto or off the gear or sprocket
wheel or wheels they each severally turn with respect to one another on the knife
edges only, whether the knife edge or edges forms or form part of that link which
is turning or not. Each alternate link may be provided with two knife edges, or
with two bearings for knife edges (as hereinafter described) or with a knife edge
and bearing each, in the former case the links might each be symmetrical and in
the latter might all be alike, or in various modifications or combinations of these
arrangements, or a series of links may be arranged in any of these ways, that is to
say a set of say two, three or more may be alike and of one form and the next
two, three, or more may be alike and of another form and so on throughout the
length of the chain.
It is also or may be arranged that the links. convey or receive the power to or
from the gear or sprocket wheel or wheels by bearing with their knife edges on
the teeth of the gear or sprocket wheel or wheels, so that when the liuks leave or
pass onto the gear or sprocket wheel or wheels they (the links) turn on their
knife edges only with respect to the gear or. sprocket wheel or wheels. The
same knife edge or edges may or may not be used for this purpose as is or are
used to convey or receive the power to or from one link to another. In the
latter case the position of knife edge or edges and bearing or bearings may be
reversed, that is to say the knife edge or edges may form part of the gear or
sprocket wheel or wheels and the bearing or bearings form part of the links, or
the knife edges and bearings may exist on both.
The use of knife edges and their bearings is well known as a means of minimising
friction in the moving parts of weighing machines and balances, and hence from
the above description the advantages of the adaptation of such to the chains of
bicycles &c. or other machinery where the minimising of friction is important, are
apparent.
arrange-
Rollers may also be used in place of knife edges in any of the above
ments, on the gear wheel or wheels, or on the links, some or all, or on both gear
wheel or wheels and links. The rollers may also be used in connection with any
of the above arrangements of knife edges, some of the knife edges being replaced
by rollers or a combination of knife edges and rollers.

page_text: Where rollers are used. I may. arrange them. so that one or more roller surface or
surfaces bears or bear against one or more roller surface or surfaces.
My invention will be the better understood by reference to the accompanying
drawings. These must be considered however as only setting forth one of the
modifications, given in the text above, in a more or less practical manner.
a
Fig. 1 represents the chain A passing over a gear wheel B. The chain is
composed of symmetrical links, the alternate ones being alike, that is to
say a, c, e &c. are alike, and different to b, d, f, &c. which are alike.
a and are shown separately in Fig. 2. is composed of two side plates g, h,
joined together by two cross pieces i, j, which form the knife edges or practically
knife edges, hereinafter called knife edges. i and j may be rivetted to g
and or secured in any convenient way. g and may be kept apart by means
of a small step or shoulder at k and / or there may be a step or shoulder
on any of the four sides of the knife edges as may be considered most convenient.
b consists of two plates m and n only, each one being provided with two holes cut
to a convenient shape. Projections o and p on the knife edges i and j serve to
keep m and n at their proper distance apart. The teeth of the gear wheel pass
between 9 and has the chain passes over or around the gear wheel. It is advisable
to allow a slight clearance between the back or non-driving side of the tooth (the
gear wheel B is supposed to be driven by the chain in the direction of the arrow)
and the knife edge in front as at C. (Fig. 1). Hence it is necessary to support the
links as they pass round the gear wheel, that is, to keep them at a constant distance
from the centre of the gear wheel. This may be conveniently done by providing a
rim or ledge or projection D on which the under side of the links bear as they
pass round the gear wheel. The under sides of the links are provided with pro-
jections for resting on the rim D, and are so arranged that directly one link begins
to turn with respect to its neighbour on coming off or going on to the gear wheel,
the aforesaid projections on the under sides of the links leave D without rubbing
on it. The projections, as drawn, are circular, and eccentric with respect to the
point (edge of knife edge practically) round which the link turns with respect to
its neighbour, the centre of the projection being slightly in advance when coming
off and slightly in the rear when going on to the gear wheel. It is clear that any
form of projection will do provided it fulfils the above conditions. It will thus be
seen that each and every link goes on to or comes off the gear wheel without
rubbing or friction; and that each link turns with respect to its neighbour on the
knife edge only, practically doing away with friction.
For convenience in fitting the chain to a machine it is necessary to provide a
messenger or joint link. In Fig. 3 the knife edges are extended through the sides
of 9 and h of the link a and are threaded and provided with nuts; lock nuts, split
pins or cotters, or a combination of them may be provided as an additional
security. Or a device as in Fig. 4 may be used (shown in plan and elevation).
A slide fits into two notches cut in the extensions of the knife edges and is
secured by a set screw r. Or a button may be provided turning round a pin or
set screw at r and engaging in notches cut in the extensions of the knife edges.
The button may be secured from turning by means of another set screw or piu, or
by means of a spring or by punching an indentation on the under side thereof the
said indentation fitting (i.e. "springing") into a corresponding hole in the side of
the link.
Fig. 5 shows chain and gear wheel fitted with rollers. Rollers s, s, s, &c. are
mounted on the periphery of the gear wheel. Rollers t, t, t, &c. are mounted on
the chain. It will thus be clear that as each link passes onto or off the gear
wheel, engagement only takes place through the medium of the rollers, thus
minimising friction.
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:
To do away with friction as far as possible in the conveving of power from one

page_text: place to another by means of chain gearing by the introduction of knife edges (or
practically knife edges) to convey the power from link to link and from link to
gear wheel and from gear wheel to link, substantially as described and for the
purposes set forth.
Dated this 1st dan
1000