Improvements in Gear-chains for Velocipedes and other Machines.
Year: 1894

page_text: Date of Application, 2nd Oct., 1894
Complete Specification Left, 2nd July, 1895-Accepted; 10th Aug.,
1895
PROVISIONAL SPECIFICATION.
Improvements in Gear-chains for Velocipedes and other Machines.
We, JOHN BOYD DUNLOP, Veterinary Surgeon, and JOHN BOYD DUNLOP,
Junior, Student, both of Talbot House, Blackrock, County Dublin, Ireland, du
hereby declare the nature of this invention to be as follows:-
This invention relates to gear-chains for velocipedes and other machines and has
for its object to reduce the friction between the parts of the chain at the joints, and
also between the chain and the chain-wheels.
Our improved chain is composed of links, pins or rivets and washers, or flanges.
The links may be in the form of rings,, preferably elongated, or in the form of
plates having holes in each end. The bearing surfaces of the links, that is to say
the surfaces which bear on the pins are curved to a radius preferably somewhat
less than half the length of a link.
With the object of causing the chain to wear for a longer time the bearing
surfaces of the links. may be made broader and the broad end of each link caused
to project into the link bearing on the opposite side of the same end of the
same pin.
The pins are preferably thicker in the middle than at the ends, or a barrel or
short tube may be passed on to the middle of the pins.
The ends of the said pins may be oval but are preferably round.
The washers have holes corresponding in size to the ends of the pins.
In building up the chain a washer is first passed on to each end of the pins, then
the links are placed in position and afterwards another washer, the ends of the pins
being riveted over the outermost washers.
The object of the links being formed as described is to obtain a free rolling
motion between the pins and the links, in or near the centre of the ends of the
links, and also, between the pins and the chain-wheel.
The inside wasbers are employed to prevent the links coming in contact with
the chain-wheel and at the same time to prevent a rubbing or grinding action being
set up between the links and the pins.
The outside washers maintain the links in position against the inside washers.
The central portions of the pins fall into the grooves or spaces between the
teeth of the chain-wheels and the pins ouly are supported thereby.
In a modification, of our invention we build up the chain by placing the links on
the centres of the pins and washers and short tubes on the ends of the pins.
With a chain of this description it is generally necessary to employ chain-wheels
having a circumferential groove in which the links are received.
We sometimes provide the links with a hole in one end corresponding in size to
the thickness of the pins and a hole in the other end, the bearing surface of which
is curved to a radius somewhat less than the length of the link. In this case the
rolling motion is confined to one end of the link.
We sometimes make a chain after the form of a block-chain the alternate links
of which fall between the teeth of the chain-wheels. Short pins are placed in and
fit into the ends of the links which fall between the teeth, or the inside ends, of
these links may be made convex with a curve equivalent to said pins. The other
links.which fall on the sides of the teeth are rectangular in form with their inside
ends straight or slightly concave. Only the links which have short pins in their
ends or convex inside ends are supported on the gear-wheels. By these means we

page_text: obtain a rolling motion between the links of the chain and also a more extended
bearing surface.
Dated this 2nd day of October 1894.
HASELTINE, LAKE & Co.,
.45 Southampton Buildings, London, W.C., Agents for the Applicante.
improvements in Grear-chains for velocipedes and other machines.
We, JOHN BOYD DUNLOP Senior, Veterinary Surgeon, and JOHN BOYD
DUNLOP, Junior, Student, both of Blackrock, Dublin, Ireland, 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 gear-chains for velocipedes and other machines and has
for its object the reduction of the friction between the pins and the links, and also
between the chain and the chain-wheels.
For this purpose we provide extended bearing surfaces at one end or at both
ends of the liuks or side-plates on which surfaces the pins connecting the
links roll.
Our invention includes an improved block-chain, that is to say, a chain the
alternate links of which are received between adjacent teeth of the gear wheels
while the remaining links of the chain pass over the teeth.
We are aware that roller chains have been heretofore used and that knife-edged
pins or rivets have been used in chains. But in such chains the links having
concave bearing surfaces are directly supported by the wheels which causes
considerable friction since the direction of pull is not tangential to the bearing
surface when the links are passing on to or leaving the wheels.
In order that our invention may be clearly understood we will now describe the
Bame with reference to the accompanying drawings, in which,
Figure 1 is a plan of a portion of a gear-chain constructed according to our
invention.
Figure 2 is a scetion taken on the line, a Figure 1.
Figure 3 is a similar section shewing a modified form of link or side-plate.
Figures 4 and 5 show in plan and side view another modified form of link or
side-plate constructed according to our invention.
Figure 6 is a plan of a portion of another chain constructed according to our
invention.
Figure 7 is a plan of a portion of a chain shewing a further modification in the
shape and arrangement of the links.
Figure 8 is a side view of the same with the washers removed in order that the
shapes of the links may be clearly seen.
Figure 9 is a side view of another piece of chain having a different shape of
link.
Figure 10 is a plan shewing a still further modification of our improved chain.
Figure 1 is a side view, and
Figure 12 is a plan, of two links of a block-chain constructed according to our
invention.
Like letters of referenco denote similar parts throughout the drawing.
A, A are the links or side-plates of the chain; B, B are the pins or rivets which
connect the links together. The said pins are made of uniform diameter throughout
and are furnished with tubes or sleeves B' as shown in Figures 1 and 7 for the
purpose of maintaining the side-plates the proper distance apart. In lieu of the
sleeves B the pins may have collars formed thereon.
The links have the form of elongated rings in Figure 2, and of plates having

page_text: large eyes near their ends in Figure 3. The surfaces A', A' of the links, against
which the pins B, B' bear are made longer than the diameter of the ends of the pins
so that a rolling contact is permissible hetween the links and pins, the friction.
between them being thereby considerably reduced.
The bearing surfaces A', A' shown in Figures 2 and 3 are preferably curved to
a radius somewhat less than half the length of the link, and those shown in
Figures 8 and 9 are preferably curved to a radius somewhat less than the length of
the link.
Washers C, C Figure 1 are interposed between the links and the collars B¹, B¹
of the pins, and other washers C C are placed on the pins outside the links and are:
secured thereon by rivetting the ends of the pins.
The bearing surfaces of the links or side-plates shown in Figures
and 5.are-
made broader than the remaining portions of the links by means of side
projections A, A2 which are arranged in such a manner as to extend into the.
adjacent links.
The chain is built up as follows, that is to say, the sleeves B1 and washers C₁ C₁
are placed on the pins, then the links A, A and the outer washers C, Care placed
in position and the ends of the pine are rivetted over the said outer washers to hold.
the parts of the chain together.
The ends of the pius may be round or oval in transverse section, the washers.
being provided with holes to correspond therewith.
The inside washers C, C' prevent contact of the links with the chain-wheel and thus.
avoid the continual shifting of the links with respect to the pins which would occur
were the links allowed to come into contact with the wheels. The central portions
of the pins or the sleeves thereon are supported in the grooves or spaces between.
the teeth of the chain wheels, and are the only parts of the chain which bear on
the wheels, the links being arranged to work out of contact with the wheels.
In the modification of our invention shewn in Figure 6 the links are mounted on
the middle portions of the pins, and washers C, C and short sleeves or ferrules B³, B³
are placed on the ends of the pins. The pins are then rivetted over the outer ends
of the ferrules as shown. With a chain of this description it is necessary to.
employ chain wheels each having a deep circumferential central groove in which.
the links are received in order that the ferrules B' only may be directly supported
by the wheels.
We sometimes construct gear-chains in which the rolling motion is confined to
one end of each of the links. For example the links may have the form of
triangular rings as shown in Figure 8 one end of each link being formed with a.
small bearing surface A, the other end having a longer bearing surface A¹
The links may also be made of plates of the form shown in Figure 9 in which.
case the hole A at one end of each link is formed to fit the pin B which is preferably
round as shewn the said pin being rivetted therein, the other end of each link
having a slot which forms a long concave bearing surface A' for the pin. In both
cases we prefer that the links should not be flat but be bent as shewn in Figure 7,.
which also very clearly indicates the method of building up the chain. The.
washers C in Figure 9 may be dispensed with.
In a modified form of chain having links of this description as shown in plan,
in Figure 10 the links are placed centrally and the ends of the pins are furnished
with ferrules B2 to bear on the teeth of the chain-wheel as hereinbefore described
with reference to Figure 6.
In the block chain shewn in Figures 11 and 12 alternate links thereof are
arranged to be received between the teeth of the chain-wheels, the intermediate links
being arranged to enclose the teeth.
To reduce the friction between the links, short pins Dare placed in the ends of
those links which work between the teeth, or the inside ends of these links are
made convex to form curved bearings for the adjacent links. The bearing surface
formed by the pin D is preferably made hard and may be of various degrees of
convexity or sharpness but is preferably rounded as shown. The intermediate-

page_text: links which surround the teeth are preferably rectangular in form, the insiile
surfaces of their ends being preferably slightly concave. We sometimes insert thin
hardened plates in, the ends of the links E in order to make the chain more durable.
These links which are provided with bearing, pins in their ends or with convex
inside ends are alone directly supported on the gear-wheels.
By making the links of these shapes rolling friction instead of sliding friction is
obtained between the links and pins.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is―
1. A gear-chain constructed of links having extended or long bearing surfaces
at one or both ends thereof, in combination with pins secured in washers for
connecting said links and adapted to roll on said bearing surfaces, substantially as,
and for the purpose,. specified.
2. A gear chain, constructed substantially as described with reference to either
or any of the modifications shewn in the accompanying drawing, for the purposes
specified.
Dated cuis 20 ay 01 July 100.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicants..