Year: 1892

page_text: Date of Application, 8th June, 1892-Accepted, 27th Aug., 1892
A communication from HENRI TREPREAU, of Angers, in the Republic of France,
Mechanical Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
Member of the Institution of Mechanical Engineers, 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 an improved mechanism for multiplying the speed of
cycles without the employment of a chain.
In the accompanying drawings,
Figure 1 is a front elevation, partly in vertical section of a portion of a driving
wheel of a velocipede provided with the improved speed multiplying mechanism.
Figure 2 is a sectional side elevation the section being taken on line A B of
Figure 1.
Figure 3 is another sectional front elevation, on line C D of Figure 1.
Figures 4 and 5 are supplemental diagrams.
From these drawings it will be seen that the improved chainless gearing for
multiplying the speed of velocipedes is constructed as follows:-
:-
The hub E of the driving-wheel is provided on each side with a slightly tapering
sleeve F upon which is fitted a collar or disc G the central opening G' of which is
also taper so as to tightly fit the sleeve F.
The central perforation H of the sleeve F is screw-threaded and adapted to
receive a sleeve or socket H¹ which acts as a nut, and the head H2 of which, by
engaging in a corresponding recess H³ provided in the collar or disc G, secures this
disc in the desired position upon the driving-wheel. This adjustment is further
assisted by a pin I, acting as a key and engaging with the hub E of the wheel at
one end and with the hub of the disc G at the other end.
The hub of the collar or disc G on its outer edge is provided with a groove J
which receives the balls J¹ which are also partly received in the groove J' formed
by the two rings K K' arranged close to each other so as to cover in the disc G.
These rings are provided with an external screw-thread and adapted to be screwed
into an eccentric bushing or perforation K' provided in the circular plate L flanged
and internally screw-threaded at L¹. Openings L' are provided in the external
surface of the ring K¹ to enable the same to be more or less tightly screwed, or
unscrewed by means of a suitable tool or key for the insertion of balls; the ring K
is stationary and by suitably tightening or loosening K₁ the pressure upon the balls
between the two rings may be increased or decreased as required.
The external surface of the ring K¹ extends partly over the hub of the
disc G which is provided with a washer M of any suitable material forming an
air-tight joint with the ring K₁ screwed against it.
The disc G is provided on its outer surface with a suitable number of
spindles, studs or journals N (which may be integral with the said disc) arranged
in a circle concentric with the axis of G. These spindles or journals carry
loose rollers N¹ with slightly rounded edges, which are adapted to come into
contact with, and travel in recesses provided on the inner side of the flange
of a plate or disc O' arranged at the outside of G. This disc O' on its periphery
is provided with a groove O for the reception of balls R; and it is located
within the casing O' formed by the plate L.
From the centre of the disc O' projects a boss P provided with a washer or
suitable packing P₁, and from its centre also extends the spindle P' adapted to
receive the crank Q to the end of which is secured the pedal. Into the internally
P

page_text: screw-threaded flange L' of the disc L is tightly screwed a ring Q', which is
stationary, and in front of which is adjustably arranged its counterpart or
companion ring Q2. The opposite surfaces of these two rings are so grooved as to
form a way or race, corresponding to the groove O' for the balls Ŕ to rest and
travel in. The outer surface of the ring Q³ is extended at O so as to partly over-
lap the boss P.and press upon the packing Pin order to tightly close the joint
between the parts just described. Recesses R' provided in the external surface of
the ring Qenable the said ring to be adjusted by screwing or unscrewing by
means of a suitable tool or key in order to increase or decrease the pressure upon
the balls R as required.
It will be seen from Figures 1, 2 and 3 that the body of the case, formed by the
disc L, its flange L' and the sleeve K2 is split at the upper part (at S) and
provided with ears or lugs S¹ S' which engage with the lower ends of the arms of
the front fork T of the machine and are permanently fixed therein by means of
bolts and nuts T' which cannot become accidentally unscrewed or loosehed.
Owing to the slit S the parts fitted together by means of screw-threads, as the
rings QQ within the flange L' of the disc L or the rings KK within the sleeve
or boss K³ may be very powerfully and tightly clamped in position.
At X Figure 1 the inner arrangement of the parts is clearly shown, while at X¹
of the same figure may be seen the outer aspect assumed by the whole of the parts
on each side of the hub E of the driving wheel, as described above.
Special attention is called to the fact that the space allowed for the balls or
rollers above referred to is closed with absolute tightness by means of the washers
or packing rings M and P¹ so that every essential portion of this mechanism is
thoroughly protected from dust, mud, moisture, or other damaging influences;
and the whole is enclosed in a case containing a sufficient quantity of oil for the
continuous lubrication of the inner parts of the mechanism. The oil is admitted
through a channel U closed by a spring or spring-controlled lid U' as shown in
Figure 2.
From the foregoing the operation of the improved speed multiplying mechanism
will be readily understood.
The principle is based upon the fact that when a circumference of a certain
diameter rolls without sliding within another circumference of a. larger diameter,
all the points of the smaller circumference are displaced; and that this displace-
ment takes place
1) On straight lines, diametrical to the large circumference, where the diameter
of the large circumference is double that of the small circumference as in Figures 1
and 2 or
2) Along a curve termed hypocycloid where the diameter of the large
circumference is either more or less than double that of the small circumference,
as illustrated by the diagrams 4 and 5.
This principle is carried out in practice, as applied to velocipedes by arranging
within the disc O' a second disc G so that
1) If the multiplied speed should be double the initial speed, the pivots of the
rollers N¹ pass through the centre of the disc O' and by providing the inner
periphery of the said disc O¹ with diametrically opposite recesses O.
2) If the multiplied speed should be more than double the initial speed, by
making the diameter of the disc G less than half that of the disc O and by
providing the inner circumference of the said disc O' with recesses O formed
on hypocycloid lines (Figure 4) or
3) If the multiplied speed should be less than double that of the initial speed,
by making the diameter of the disc G more than half of that of the disc of and
by providing as before the inner periphery of the disc O¹ with recesses O,having
hypocycloid outlines.
The result of this special arrangement is that by acting upon the crank.Q.the
rotation of the disc is directly produced, and is transmitted by the contact
between the recesses O and the rollers N¹.to the disc G which in its turn conveys

page_text: the motion to the driving wheel, upon the hub E of which is secured the said disc;
the initial speed being multiplied according to the diameter of the disc G.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent, and in what manner the
same is to be performed I declare that what I claim is :-
1. A chainless speed-multiplying mechanism for cycles in which the rotary
motion imparted by the pedals to a plate or disc such as O¹ rolling upon balls
within a fixed case O' is transmitted to the hub E of the driving wheel arranged
eccentrically in relation to the disc O₁ this hub E also rolling upon balls within a
sleeve or collar such as K' integral with the case O³ through the medium of
another ring or disc such as G secured to the said hub E and carrying a series of
pivots or studs N upon which are adapted to turn rollers such as N¹ engaging with
suitably shaped recesses O provided in the disc 0₁ substantially as described and
illustrated in the accompanying drawings.
2. In chainless speed-multiplying mechanism the arrangement within a casing
such as Os and sleeve such as K' of two rings Q'Q' and K K' respectively screw-
threaded and grooved in such a manner as to form grooves or channels Q³ and J'
for the balls to rest and move in and so arranged as to be capable of being taken
to pieces or allowing the pressure on the balls to be adjusted and wear to be
compensated for substantially as described and illustrated in the accompanying
drawings.
3. In chainless speed-multiplying mechanism the tight closing of the whole of
the mechanism enclosed in the casing O and the sleeve K' by means of packing
rings or washers such as P and M against which are tightly fitted the extensions
or flanges of the rings Q and K' substantially as described and illustrated in the
accompanying drawings.
4. In chainless speed multiplying mechanism the employment of a slot such as S
in connection with the case O and sleeve K' for the purpose of enabling the screw
threaded parts to be tightly clamped so as to prevent displacement or shifting
thereof substantially as described and illustrated in the accompanying drawings.
5. The combination and arrangement of parts constituting the complete
chainless speed-multiplying mechanism substantially as described and illustrated in
the accompanying drawings.
Dated this 8th day of June 1892.
ALFRED J. BOULT,
Chartered Patent Agent.