Improvements in Free-wheel Clutches for Cycles.
Year: 1899

page_text: Date of Application, 28th Sept., 1899
Complete Specification Left. 28th June, 1900-Accepted, 28th July, 1900
Improvements in Free-wheel Clutches for Cycles.
I, HERBERT EDWARD COHEN, Manufacturer, of 2-8, John Bright Street, in
the City of Birmingham, do hereby declare the nature of this invention to be as
follows:-
This invention relates to cycles, and has distinct reference to what are well
known in the trade as free-wheel clutches.
The clutch according to this invention combines both ratchet and frictional
types, but the pawl and wedge, or the pawls and wedges, working within notches
or ratchet teeth and upon the inclined planes are constructed, fitted, and arranged
within the parts of the clutch in the particular manner hereinafter described.
In carrying the invention into effect upon the rear wheel hub of a cycle and
in conjunction with the chain wheel mounted thereon, a number of ratchet teeth
are cut within the circular bore of the chain wheel, the said wheel being of a
ring formation to freely fit over and upon a cylindrical boss or disc, rigidly
attached to the said hub on the one side so that the said boss moves only with
the hub. Within the periphery of this boss or disc is machined a cavity or cut-
away part curved upon its bottom or the greater part thereof, and within one
end of this cavity is drilled a small hole for the reception of a similar sized
coiled spring, the said hole being preferably in a radial line with the curvature
of the bottom of the cavity. The said cavity is preferably machined within the
periphery of the boss from the outer side or face thereof, and afterwards closed
by a detachable plate which fixes upon its side. Lying within the cavity or cut-
away part, as aforesaid, so as to fit between the bottom of it and the bore of the
chain wheel is a pawl or a pawl-like gripping piece, curved or rounded upon its
inner edge to the curved bottom of the said cavity, and of a size sufficient to
admit of it moving slightly, in a longitudinal direction, within the said cavity.
The nose or forward end of this pawl-like gripping piece is adapted to engage the
notches or teeth of the chain wheel when forward driving (viz. when the hub or
chain wheel move as one), and the tail end to abut against the opposite end of
the cavity and force itself against the bore of the chain wheel wedge-like; thus
effecting the locking of the chain wheel to the boss; the small coiled spring at
this time being forced back wholly within the hole wherein it fits. The said pawl
or pawl-like gripping piece is practically a combined catch and wedge with a
shifting fulcrum and an inclined wedging plane, formed by the curved surfaces
of the cavity and the bore of the chain wheel.
The spring acting upon the tail end of the pawl or piece is active immediately
free running of the boss (without the chain wheel) is broken by a movement
being given to the chain wheel, so that it forces the nose end of the pawl or
piece into engagement with one of the notches or ratchet teeth on the chain
wheel immediately it comes opposite any one of them. In the free running
movement the inclined parts upon the notches or ratchet teeth force the nose
end of the pawl or piece out of engagement with the said notches by shifting the
said pawl or piece bodily in the cavity, but the wedge-shaped tail end is kept by
the spring from acting upon the two parts of the clutch to jamb them. One,

page_text: two, or more of such pawls or pieces and cavities may be used, with any number
of ratchet teeth in the chain wheel, and the pawls may be fitted to the chain
wheel and the ratchet teeth to the boss with an equivalent result.
In a modification, the ratchet teeth or notches on the chain wheel may be
dispensed with, and the bottom of the cavity may be inclined up towards the
nose portion of the pawl or piece, the latter in this form being a friction gripping-
piece working in the cavity between the two parts of the clutch and kept up to
a wedging point by the coiled spring acting upon its back end or tail. In this
form the forward end of the cavity may be inclined as well as the bottom. The
gripping piece has a movement in the cavity similar to the pawl or piece in the
first form.
A free-wheel clutch constructed as aforesaid is positive and soft in its action,
and its manufacture or production is extremely simple on account of its parts
requiring no fitting; further, there are no such loose parts as fulcrum, joint and
set pins to work loose and render the clutches construction weak.
W. P. THOMPSON & Co.,
11, Burlington Chambers, New Street, Birmingham.
Agents for the Applicant.
I, HERBERT EDWARD COHEN, Manufacturer, of 2-8, John Bright Street, n
the City of Birmingham, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to free-wheel clutches for cycles, and consists of the
improvements hereinafter set forth by which such clutches are made positive
and soft in their action, or in their working, their manufacture or production
rendered simple on account of their parts not requiring fitting, and there being
in them no such loose parts as fulcrum and joint pins to work loose and render
their construction weak.
A free-wheel clutch built with the improvements according to this invention
embraces a combination of both ratchet and frictional types of clutch, inasmuch
as a combined pawl and wedge, or a number of such is or are provided and fitted
within it to work in notches or ratchet teeth and between inclined planes so as
to bring about a sensitive slip and grip action between the different parts of the
clutch. A clutch according to the foregoing and constructed with the improve-
ments according to this invention is shown in the accompanying sheet of drawings
by Figs. 1, 2 and 3; the first named being a side elevation, partly in section, of
a cycle chain wheel formed as a clutch; Fig. 2 a transverse section of Fig. 1 on
the dotted lines; and Fig. 3 side views of the parts Fig. 1 separate. In this form
of clutch three combination pawls and wedges, or pawl-like gripping pieces, are
provided, but it is obvious that any number of such may be used
In describing the improvements in connection with Figs. 1 to 3 of the sheet
of drawings a number of ratchet teeth or notches a² are cut within the circular
bore a³ of the outer part a of the clutch, the said outer part being formed as a
chain wheel and of a ring construction to freely fit over and upon a cylindrical
boss or disc c constituting the inner part of the clutch and which is adapted
to be rigidly attached upon the rear wheel hub of a cycle, on the one side, so that
the said boss moves only with the hub. Within the periphery or outer circum-

page_text: ference of this boss or disc c is machined three cavities or cut-away parts c³,
3,3, curved upon their bottoms d or the greater part thereof. Within one end
of each cavity is drilled or otherwise formed a small hole e for the reception of a
similar sized coiled spring f, the said hole being preferably formed on a radial
line with the curvature of the bottom of the cavity or cut-away part.
The cavities or cut away parts are machined from the solid of the boss or disc c
and are afterwards closed at the side by detachable plates, g, g², which are clamped
to the said boss by screw pins g³, the said plates closing in the sides of the
clutch to keep the parts of it in position. The said cavities may however be
machined within the boss from the one side, in which case one of the plates g
g2, might be dispensed with.
Lying within each cavity c³ as aforesaid, so as to freely fit between the bottom
of it and the ratchet toothed bore or inner circumference a³ of the boss, is a
combination pawl and wedge, or a pawl-like gripping piece, i, curved or rounded
upon its inner edge or under side 2 to the curved bottom d of the cavity, the
said gripping piece being of a size sufficient to admit of it moving slightly in a
longitudinal direction within the said cavity. The nose or forward end, 3, of
each gripping piece is adopted to engage at different times the notches or
teeth a² of the outer part a of the clutch when forward driving (viz.—when the
parts a and c of the clutch move as one) and the tail end to abut against the
opposite end of the cavity and force itself against the bore a of the chain wheel
wedge-like, thus effecting the locking of the outer part of the clutch a to the
inner part e the coiled spring e at this time being forced back wholly within the
hole wherein it is seated.
The spring e is always pressing against the tail end of the gripping piece i,
but its active movement is one immediately the free running of the boss (with-
out the part a) is broken by a driving movement being given to the said part a,
so that it forces the nose end of the pawl or piece into engagement with one of
the notches or ratchet teeth on the part a immediately the said nose end comes
opposite any one of them. In the free running movement of the clutch the
inclined portions of the notches or ratchet teeth wipe over the nose end of the
pawl or piece and force, the said piece out of engagement with the said notches
by shifting the pawl or piece in the cavity as clearly shown in Fig. 1, the wedge-
shaped tail end being kept by the spring from acting between the two parts a
and of the clutch to jam and frictionally connect them.
In Fig. 1 it will be seen that only one pawl or pawl-like piece of the three
engages the ratchet teeth at a time, the other two being out of engagement, but
if needs be the three pawls could be made to become active at one time.
The cavities or cut-away parts may be formed in the outer part a of the
clutch and the ratchet teeth or notches in the boss with a similar effect as the
arrangement shown in the drawings.
In the modification shown in the drawings in Fig. 4 the ratchet teeth or
notches are dispensed with and the bottom d of the cavity inclined up towards
the nose end of the gripping piece i, the latter in this form being a friction
gripping piece only working in the cavity between the two parts a and c of the
clutch and kept up to a wedging point by the action of a coiled spring e at its'
back end or tail. In this modification the piece has a movement in the cavity
somewhat similar to the pawl or piece in the first form.
It is to be understood that any number of ratchet teeth or notches may be
machined in the one part of the clutch at either equal or unequal distances
apart, and any number of pieces i and cavities may be employed irrespective of
equal or unequal arrangement.
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:-
First. A free wheel clutch for cycles characterised by ratchet teeth or notches

page_text: formed on the one part of the clutch, cavities or cut-away parts formed within
the other part of the clutch adjacent to said notches, and combination pawls and
wedges lying and working loosely, or with an amount of play within said cavities
and engaging the said ratchet teeth or notches, and springs located in said cavities
to act on the ends of said pawls and wedges, substantially as described.
Second. A free wheel clutch having in its combination an outer part formed
with ratchet teeth in its bore, an inner part surrounded by said outer part and
in which are machined a number of cavities or cut-away parts c³, a number of
combination pawls and wedges lying in said cavities between the bottoms
thereof and the ratchet teeth, said pawls and wedges having an amount of
play in said cavities, and springs e acting on the tail end of said pawls and
wedges, substantially as described and set forth.
Third. A free wheel clutch for cycles constructed and having its parts arranged
and fitted substantially as described and illustrated in Figs. 1 to 3, and also in
Fig. 4.
d this 27th day of June 1900.
W. P. THOMPSON & Co.,
11, Burlington Chambers, New Street, Birmingham.
Also at Liverpool, London & Manchester.
Patent Agents for the Applicant.