Improvements in Chain Gearing for the Transmission of Power applicable for Driving Cycles or other Machines.
Year: 1897

page_text: Date of Application, 27th Feb., 1897
Complete Specification Left 24th Nov, 1897-Accepted 26th Feb., 1898
Improvements in Chain Gearing for the Transmission of Power
applicable for Driving Cycles or other Machines.
I, JOSEPH BURTON, of .Crompton Fold, Clifton, in the County of Lancaster,
Technical Chemist, do hereby declare the nature of this invention to be as follows:-
This invention relates to driving chains such as are employed for cycles and other
classes of machinery.
It is desired to provide a chain in which side friction between the links of the
chain and the teeth of the gear wheels will be eliminated and the friction of the
moving parts of the chain will be reduced to the least possible amount.
I construct the chain with links pinned or pivoted together with wheels placed
upon the pins to rotate thereon.
The link wheels are formed with a groove around their peripheries preferably semi-
circular in cross section to fit over or around the teeth of the gear wheels or the
groove may be of other shape complementary to the contour of the teeth of the
gear wheels.
The sides of the link wheels are formed of a spherical curve or a curve
approximating thereto and the ends of the links are formed of corresponding shape
so as to reduce the friction between them by eliminating or reducing part of
the perpendicular thrust.
Instead of being curved at the sides the link wheels may be formed with
shoulders to bear against the sides of the links which would then be flat or
straight.
The teeth of the gear wheels are preferably formed of a shape to give the least
amount of friction on the chain. I describe an arc of a circle having a radius equal
to the distance between the centres of the link wheels. This arc is sufficiently long
to give all possible positions of the centre which it represents. This arc serves as
centre for a rolling circle and I describe a curve tangent to such rolling circle which
gives the curve for each tooth. In cross section I make the teeth semi-circular or
approximately so or otherwise complementary to the cross section of the link wheel.
Although I prefer to employ gear wheels of this construction the improved chain
may be applied to sprocket wheels of ordinary form or construction the faces of the
teeth of which have been curved or shaped to correspond with the grooves in the link
wheels.
The link wheels in the chain may be spaced so that the teeth of the gear wheels
may enter each space between them or each alternate space.
The groove in the link wheel embraces the teeth of the gear wheels and all side
friction between the links of chain and teeth of gear wheels is removed.
Dated this 25th day of February 1897.
WM. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents."

page_text: Improvements in Chain Gearing for the Transmission of Power
applicable for Driving Cycles or other Machines.
I, JOSEPH BURTON, of Crompton Fold, Clifton, in the County of Lancaster,
Technical Chemist, 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 relates to driving chains, such as are employed for cycles and other
classes of machinery.
It is designed to provide a chain in which side friction between the links of the
chain, and the teeth of the gear wheels will be eliminated, and the friction of the
moving parts of the chain will be reduced to the least possible amount.
It consists essentially in constructing the chain with links, pinned or pivoted
together with grooved wheels or pulleys, pivoted on the pins to rotate thereon, and
the wheel with teeth to work in conjunction therewith, the faces of which are curved
to correspond with the groove of the chain wheel or pulley.
It will be fully described with reference to the accompanying drawings.
Fig. 1. Side elevation of my improved chain.
Fig. 2. Plan of same.
Fig. 3. Sectional elevation showing two forms of construction.
Fig. 4. Side elevation of chain wheel for crank axle.
Fig. 5. Transverse section of same, showing one link of chain in position at
bottom of tooth.
Fig. 6. Side elevation of chain wheel or ring for hub.
Fig. 7. Enlarged elevation of part of chain wheel.
Fig. 8. Enlarged elevation of chain wheel or ring of hub.
Fig. 9. Similar view, showing modification.
Fig. 10. Enlarged side view of chain.
Fig. 11. Enlarged side elevation showing modified construction of teeth.
The links A forming the chain are connected by the pins a riveted or otherwise
secured in the ordinary way. Upon the pins or pivots a are placed the grooved
wheels or pulleys B which are free to rotate thereon.
The link wheels B are formed with a groove 6 around their peripheries approxi-
mately semi-circular, in cross section to fit over or around the teeth of the gear
wheels D, or the groove may be of other shape complementary to the contour of the
teeth of the gear wheels, to prevent the sides of the wheel teeth d coming into
contact with the links A.
The sides of the link wheels B are preferably formed of a spherical curve, b¹ Fig. 3
or a curve approximating thereto, and the ends of the links A are formed of
corresponding shape, so as to reduce the friction between them by eliminating or
reducing part of the perpendicular thrust.
"
Instead of being curved at the sides, the link wheels may be formed with shoulders
to bear against the sides of the links, which would then be flat or straight.
The teeth d of the gear wheels D are constructed of a shape to create the least
amount of friction with the chain. In Figs. 4 to 8 the teeth are shown of just
sufficient depth to engage the link wheels B of the chain the bottom of each tooth
being curved to exactly correspond to the periphery of the link wheel a single circle
forming the bottom of the two teeth. In Fig. 9 the bottom of each tooth is the
same curve but the teeth are narrower so that the link wheel B will only touch one
side of the tooth. Where deeper teeth are found desirable as shown in Fig. 11 the
teeth are designed by two arcs x-x of circles the radius of each being equal to the

page_text: distance between the centres of the link wheels B. The arcs xx are sufficiently long
to give all possible positions of the centre which they represent, and serve as centre
lines for a rolling circle y and I describe a curve tangent to such rolling circle, which
gives the curve for each tooth. In cross section I make the teeth d semi-circular or
approximately so, or otherwise complementary to the cross section of the link
wheel.
Although I prefer to employ gear wheels D of this special construction, the
improved chain may be applied to sprocket wheels of ordinary form or construction,
the faces of the teeth of which have been curved or shaped to correspond with the
grooves 6 in the link wheels B.
The link wheels B in the chain may be spaced so that the teeth d of the gear
wheels may enter each space between them or each alternate space.
The groove in the link wheel embraces the teeth of the gear wheels, and all side
friction between the links of chain and teeth of gear wheels is removed.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the saine is to be performed, I declare that what I
claim is :-
1. In a driving chain for the transmission of power, the combination with the
links A and pivots a of grooved wheels B rotating thereon, substantially as and for
the purpose described.
2. In chain gearing for the transmission of power, the combination of driving chain
with grooved pulleys with sprocket wheel, the face of the teeth of which are curved
or complementary to the groove in the chain wheel, substantially as described and
shown.
3. A chain wheel or driving wheel for the transmission of power having teeth
constructed, substantially as described and shown.
4. A driving chain for the transmission of power constructed substantially as
described and shown.
Dated this 19th day of November 1807
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.