Improvements in Chain Gearing.
Year: 1897

page_text: Date of Application, 23rd July, 1897
Complete Specification Left, 22nd Apr., 1898-Accepted, 23rd July 1898
PROVISIONAL SPECIFICATION.
Improvements in Chain Gearing.
I, THOMAS HEWETT, of 6, Jeffrey's Square, St. Mary Axe, in the City of London,
Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to the improved construction of chain gearing.
Such improved chain gearing may be employed as the driving gear of bicycles
and other velocipedes and for a variety of other, or analogous uses.
My improved chain wheel I construct of two metal discs each disc being stamped
or formed near its periphery with a shoulder and then a radial extension, or flange
so that when the two discs are brought side by side and secured fixedly together
a wheel is formed with a recess or trough like annular channel in which the drive
chain may lie. The discs are for lightness and other reason formed with openings.
Some of these openings are arranged to come, oppositely disposed in each disc,
in the combined wheel below certain antifriction wheels applied on rivets or axial
pins secured on each side of the radial flanges, and so these openings form a series.
of clear spaces in the peripheral channel bed.
The edges of these openings in the discs may where convenient be made to lap
over-one disc of the other-so as to form means of union between the two discs
aided by rivets or other means of connection and to give finish. In some cases the
edges of a central hole in the combined discs may be utilized to form a boss for use
in attaching the wheel to an axis.
These parts may be accurately produced by the aid of suitable dies and presses.
I prefer to arrange the rollers, on the inside of the wheel flanges in pairs cach
pair on one side opposite a pair on the other side and I arrange the chain to co-
operate with the wheel (either to drive the wheel, or to be driven thereby, as the
case may be) with a series of central links at intervals so arranged that they shall
-in operation when in the trough of the wheel-lie between the flange rollers,
with the ends of two pairs of other links lying on either side of their ends, a rivet
securing each three rivets ends together and forming their hinge.
Between the ends of each adjacent two central links is located a short axial
rivet, or pin, which pins are journalled in the overlapping side links.
To keep these pins in true position I prefer to form the portions of their lengths
which lie inside each pair of side links of larger diameter whereby they are locked
As the chain and wheel travel the ends
in securely with facility of free rotation.
of the pins engage the side rollers of the wheel flanges. Or these shouldered pins
may have antifriction rollers mounted rotatably on their outer ends. Or the central
enlargements may be dispensed with.
The end rivets holes of the side links I prefer to form on their outer sides counter
sunk and the rivets which connect them and the central links I form of a larger
diameter within each inner link, with correspondingly enlarged holes in said and
smaller outer portions to lie within correspondingly smaller holes in the side link
ends. The projecting ends of this smaller diameter I rivet up tightly into the
counter sunk recesses and grind off any projections, not desired.

page_text: By these means I am enabled to avoid difficulties of construction and working
that have been found to arise with chain gearing where the rollers on the chains
are mounted on the same axial pins that connect the several sets of links and also
to greatly improve and facilitate the construction of such chain wheels.
Dated the 23rd day of July 1897
счать Gearing.
I, THOMAS HEWETT, of 6, Jeffrey's Square, St. Mary Axe, in the City of London,
Mechanical 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 relates to the improved construction of chain gearing and parts
connected therewith.
Such improved chain gearing may be employed as the driving gear of bicycles
and other. velocipedes, and for a variety of other or analogous uses.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 shews a side view of a gear wheel in accordance with the present improve-
ments.
Fig. 2 shows a sectional view of the same, taken on the line ax of Fig. 1.
Fig. 3 shows an edge view of the two half parts of the wheel shown in Figs. 1
and 2, said half parts being afterwards connected to form a wheel, as will be
described.
Fig. 4 shows a sectional view of such wheel, showing one method of fastening
the two halves together, and
Fig. 5 shows another method by a part sectional view.
Fig. 6 shows a side view of a portion of the larger, or driving wheel; the smaller
or driven wheel being shown by Fig. 1.
Fig. 7 shows a side sectional view of the wheel shown in Fig. 1 but having anti-
friction rolls applied thereto, the section being taken on the line y-y, of Fig. 8,
said figure showing the same wheel by a plan view.
Fig. 9 is a detail sectional view of one of the rolls, on a larger scale, and
Fig. 10 shows a supporting stud or rivet for such roller, also on a larger scale.
Figs. 11 and 12 show by side view and edge view respectively an improved
chain for use with the chain wheels shown in the previous figures.
Figs. 13, 14, 15, 16, 17, 18 and 19 show details of parts of the improved chain.
Figs. 20 and 21 show by side view and edge view respectively, a modified form
of chain.
Fig. 22 shows a chain such as shown in Figs. 11 and 12 engaging with the 4
chain wheel.
"
Fig. 23 shows a part sectional view of the same taken on the line -, Fig. 22.
Fig. 24 shows a chain as in Figs. 20 and 21 engaging with a portion of the
chain wheel.
My improved chain wheel I construct of two metal discs a, a, each disc being 4
stamped or formed near its periphery with a shoulder b and then a radial exten-
sion c or flange, so that when the two discs are brought side by side and secured
fixedly together a wheel is formed with a recess, or trough like annular channel d
in which the drive chain may lie.

page_text: The discs a, a, are for lightness and other reasons formed with openings a¹, a¹.
Some of these openings are arranged to come oppositely disposed in each disc, in
the combined wheel below certain anti friction wheels e applied on rivets e, or
axial pins, secured on each side of the radial flanges c and so these openings form
a series of clear spaces in the peripheral channel bed for the escape of mud and
dirt.
The edges of these openings in the discs may where convenient be made to lap
over one disc of the other-as shown in Figure 5, so as to form means of union
between the two discs, aided by rivets a² or other means of connection and to give
finish. In some cases the edges of a central hole a³ may be utilized to form
a boss for use in attaching the wheel to an axis.
These parts may be accurately produced by the aid of suitable dies and presses.
I prefer to arrange the rollers e on the inside of the wheel flanges c in pairs,
each pair on one side opposite a pair on the other side, and I arrange the chain to co-
operate with the wheel (either to drive the wheel, or to be driven thereby, as the
case may be) with a series of central lurks 'f at intervals so arranged that they shall
-in operation when in the trough of the wheel-lie between the flange rollers e,
with the ends of two pairs of other links f¹ lying on either side of their ends, a.
rivet f securing each three links together at their ends and forming their hinge.
Between the ends of each adjacent two central links f is located a short axial
rivet, or pin f³, which pins are journalled in the overlapping side links f¹. To
keep these pins in true position I prefer to form the portions of their lengths of
larger diameter, at f4, whereby they are locked in securely with facility of free
rotation.
As the chain and wheel travel
of the wheel flanges-see Fig. 24.
rollers 9 mounted rotatably on
at f may be dispensed with.
the ends of the pins f3 engage the side rollers c
Or these shouldered pins may have anti friction
their outer ends. Or the central enlargement
The end rivet holes of the side links f¹ I prefer to form on their outer sides
counter-sunk, see Figs. 13 and 14, and the rivets f which connect them and the
central links f I form of a larger diameter within each inner link, with correspond-
ingly enlarged holes in said inner links, the smaller outer portions to lie within
correspondingly smaller holes in the side link ends. The projecting ends of this
smaller diameter I rivet up tightly into the countersunk recesses and grind off
any projections, not desired.
By these means I am enabled to avoid difficulties of construction and working
that have been found to arise with chain gearing where the rollers on the chains
are mounted on the same axial pins that connect the several sets of links and also
to greatly improve and facilitate the construction of such chain wheels.
Although I have shown the flanges c of the wheel as being fitted with pairs of
rollers e, the rollers e may be set singly, or instead of being rollers these teeth e on
the Hanges e may be fixed studs in pairs or single arrangement relatively to each
cooperating link of the chain.
In a chain gearing chain constructed as I have described, with the studs or axes
of the rollers borne in bearings formed in the links independently of the studs
connecting the links, it is found in practice that an advantage arises from this
construction that except at the moment when such chain roller teeth are actually
pulling or are being pulled by, the teeth of a wheel there is no strain on those
studs or axes, whereas in gear chains of other constructions there is a nearly
constant strain on the studs owing to their serving as connections for the chain
links as well as to carry the rollers.
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. In a wheel for chain gearing, the use of two metal discs shaped to form the
two halves of a peripherally grooved wheel, connected together by the lapping

page_text: over of the edges of openings in said discs, said lappings over being aided if so
desired by rivets or like fastenings, substantially as shown and described with
reference to Figures 2, 3 and 5.
2. A wheel for chain gearing of the construction described, provided if desired
with mud escape ports in combination with chain engaging teeth formed of pro-
jections from, or of wheels mounted on studs or their equivalents secured to, the
Hanges of the wheel forming the chain groove, substantially as set forth and shown
in the drawings.
3. In a chain gearing, the use of a chain whose rivetted connected links have
mounted thereon engaging teeth formed by wheels or projections supported
independently of the connecting rivets of the links, substantially as shown and
described with reference to Figures 11, 12, 20, 21, 22 and 24 and by details thereof
in Figs. 9, 10, 13, 14, 15, 16, 17, 18, and 19.
4. The use of a chain gearing consisting of a chain wheel constructed as described
and having rollers or wheels mounted on axes or studs secured to the insides of
the wheel flanges in pairs, each pair on the one side being opposite to the pair on
the other side in combination or cooperating with a chain constructed according
to Claim 3, all substantially as set forth and shown by the drawings
Dated the 22nd day of A 1908
WM. BROOKES & SON,
55 and 56, Chancery Lane, London, Agents for the Applicant.