Improvements in or relating to Change-speed Gear.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in or relating to Change-speed Gear.
I, CHARLES MONTAGUE LINLEY, Engineer, of 281, Oxford Street, in the County
of London, do hereby declare the nature of this invention to be as follows:-
This invention relates to change-speed gear in which there is a flexible opera-
tive connection, such as a chain, by which it is desired to be able to impart
to a driven device two or more speeds of rotation in relation to a driving wheel
whose angular velocity may be assumed as constant.
The chain pulleys and chain employed for the purposes of this invention are
of such types that the chain and wheel can be disengaged from each other by a
relative lateral adjustment, that is to say by moving the wheel endwise in the
line of its axis or by moving the chain sidewise off the wheel. A convenient
type of chain for employment in this mechanism is one in which alternate
links are made of arched form to receive a tooth in the gap of the archway which
opens out upon the side of each of these alternate links; as chains of this type
are ordinarily somewhat weak at the crown of each arch, the metal may be
thickened at the crown, the links being conveniently produced from a bar rolled
to such a form of cross-section. that its widest portion will be situated in that
part of the bar whence the crown of the arch is derived.
According to this invention, where a pair of co-axial toothed wheels of different
sizes is to be driven from a third toothed wheel by the chain, the third wheel is
made of such a width that the chain when running upon it near one of its
edges gears with say the larger of the other two wheels, whilst when running
near the other edge it gears with the smaller of the other wheels. On the end
face of the larger wheel in the pair of co-axial wheels, there is a lateral exten-
sion projecting over the smaller wheel adjacent; on to this projection the teeth
of the larger wheel preferably extend endwise and the projection preferably
merges gradually into that face of the wheel upon which it is formed, although
there are various possible shapes which it might possess.
Normally the chain will run upon one or other of the co-axial pair of wheels
without being interfered with by the projection, but by shifting the chain side-
wise or by shifting this pair endwise the teeth upon the projection will come
into gear with the inside of he bight of chain, which shall be assumeil, for the
moment, as running upon the smaller of the two wheels, and move it radially
outward from the latter. The lateral movement of the chain in relation to the
wheels is maintained whilst this is occurring, the chain thus picked up by the
toothed projection whilst it moves radially outward as described on to the larger
circumference being also shified laterally from the teeth on the projection on
to the teeth of the wheel proper of which they form a continuation, so that in
the succeeding revolution of the co-axial pair the chain will be travelling in a
fresh plane relatively to that pair so as not to drop off the projection until a
lateral adjustment be made in the opposite sense which will cause the chain to
slip over the projection and return into gear with the smaller wheel which it
is found to do very easily.

page_text: A little slack is necessary in the chain running on the small pulley to enable
it to be received upon the larger circumference of the companion pulley, and
therefore to keep it from becoming unduly loose a spring-loaded or other jockey
pulley can be used if desired.
Where a gear such as is above described is employed upon a bicycle, the pair
of co-axial pulleys may be put in line with the hub of the driven road wheel,
a clutch being interposed between them so that the hub may overrun the gear
wheels; this, in certain cases, increases the facility with which the change of
gear can be effected.
Preferably flanges are provided on the gear wheels to prevent the chain from
slipping off over their outer edges.
Although in the example above set out a single broad wheel is described as
gearing with a pair of co-axial and narrower wheels, it is to be clearly under-
stood that there may be three or more of these narrower wheels, each one having
the projection for shifting the chain from the next smaller wheel.
Where the wheels are movable endwise any convenient shifting device may
be employed for that purpose; where the chain is to be shifted an appliance
akin to a belt shifted may be used.
The larger wheels with projections upon them are so set in relation to each
adjacent smaller wheel that the distance between the last tooth on the projec-
tion and the tooth of the smaller wheel with which the chain next gears is equal
to the pitch of the chain or to some multiple thereof.
Dated this 9th day of September 1899.
BOULT, WADE & KILBURN,
Agents for the Applicant.
I, CHARLES MONTAGUE LINLEY, Engineer, of 281, Oxford Street, in the County
of London, 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 change-speed gear in which there is a flexible opera-
tive connection, such as a chain, by which it is desired to be able to impart
to a driven device two or more speeds of rotation in relation to a driving wheel
whose angular velocity may be assumed as constant.
The chain pulleys and chain employed for the purposes of this invention are
of such types that the chain and wheel can be disengaged from each other by a
relative lateral adjustment, that is to say by moving the wheel endwise in the
line of its axis or by moving the chain sidewise off the wheel. A convenient
type of chain for employment in this mechanism is one in which alternate
links are made of arched form to receive a tooth in the gap of the archway which
opens out upon the side of each of these alternate links; as chains of this type
are ordinarily somewhat weak at the crown of each arch, the metal may be
thickened at the crown, the links being conveniently produced from a bar rolled
to such a form of cross section that its widest portion will be situated in that
part of the bar whence the crown of the arch is derived.
According to this invention, where a pair of co-axial toothed wheels of different
sizes is to be driven from a third toothed wheel by the chain, the third wheel is
made of such a width that the chain when running upon it near one of its
edges gears with say the larger of the other two wheels, whilst when running

page_text: near the other edge it gears with the smaller of the other wheels. On the end
face of the larger wheel in the pair of co-axial wheels, there is a lateral exten-
sion projecting over the smaller wheel adjacent; on to this projection the teeth
of the larger wheel preferably extend endwise and the projection preferably
5 merges gradually into that face of the wheel upon which it is formed, although
there are various possible shapes which it might possess.
Normally the chain will run upon one or other of the co-axial pair of wheels
without being interfered with by the projection, but by shifting the chain side-
wise or by shifting this pair endwise the teeth upon the projection will come
into gear with the inside of the bight of chain, which shall be assumed, for the
moment, as running upon the smaller of the two wheels, and move it radially
outward from the latter. The lateral movement of the chain in relation to the
wheels is maintained whilst this is occurring, the chain thus picked up by the
toothed projection whilst it moves radially outward as described on to the larger
circumference being also shifted laterally from the teeth on the projection on
to the teeth of the wheel proper of which they form a continuation, so that in
the succeeding revolution of the co-axial pair the chain will be travelling in a
fresh plane relatively to that pair so as not to drop off the projection until a
lateral adjustment be made in the opposite sense which will cause the chain to
slip over the projection and return into gear with the smaller wheel which it
is found to do very easily.
A little slack is necessary in the chain running on the small pulley to enable
it to be received upon the larger circumference of the companion pulley, and
therefore to keep it from becoming unduly loose a spring-loaded or other jockey
pulley can be used if desired.
Where a gear such as is above described is employed upon a bicycle, the pair
of co-axial pulleys may be put in line with the hub of the driven road wheel,
a clutch being interposed between them so that the hub may overrun the gear
wheels; this, in certain cases, increases the facility with which the change of
gear can be effected.
Preferably flanges are provided on the gear wheels to prevent the chain from
slipping off over their outer edges.
Where the wheels are movable endwise any convenient shifting device may
be employed for that purpose; where the chain is to be shifted an appliance
akin to a belt shifter may be used.
The larger wheels with projections upon them are so set in relation to each
adjacent smaller wheel that the distance between the last tooth on the projec-
tion and the tooth of the smaller wheel with which the chain next gears is equal
to the pitch of the chain or to some multiple thereof.
In the accompanying drawings which illustrate one construction of change-
speed gear according to this invention applied to a bicycle,
Figure 1 is a side elevation showing the general arrangement of the gear;
Figure 2 is a perspective view drawn to a larger scale showing portions of the
gear; and
Figures 3 and 4 are respectively a side elevation and a vertical section of a
portion of the driving chain.
Like letters indicate like parts throughout the drawings.
With reference first to Figures 1 and 2 A is the rear road wheel of a bicycle
carried in the usual way in the back fork B. Upon the hub A of the wheel
are two co-axially mounted toothed wheels C and D. These wheels are con-
veniently attached to the hub A' through a clutch which may be of any well-
known form so arranged that the wheel A is free to rotate in a forward direction
without driving the toothed wheels. The details of this device, however, form
no part of the present invention and are not illustrated in the drawings.
The face of the larger toothed wheel 1 adjacent to the small wheel C is pro-
vided with a projecting portion which starts from the level of the face of the
wheel as at D (Figure 2) and gradually increases in breadth until it terminates

page_text: abruptly in a wedge-shaped face at D2. The teeth on the wheel 1) extend to
the edge of the projecting portion and therefore increase gradually in breadth.
As is clearly shown in Figure 2 the projecting portion from D to 12 overhangs
the teeth of the smaller wheel C and the device acts as hereinafter described to
assist in the easy transfer of the chain from one wheel to the other.
However the precise form of this mutilated part 11 12 may be varied greatly
without departing from the spirit of the invention so long as the desired result
of mounting the chain on to the wheel is secured.
The driving chain is composed of arched links E connected by other links F,
each of the arched links E being adapted to sit saddle-fashion upon the teeth
of the wheels C and D. In order to strengthen the arched links E they may
conveniently be formed so that the crown of the arch is of thicker metal than
the rest of the link. Such a construction of link is illustrated in Figures 3
and 4, the thickened portion being shown at E.
The driving wheel G for the chain is made of sufficient breadth to allow the
chain to run in an approximately straight line whether it be engaged with the
wheel C or the wheel D and flanges Gare provided 'upon it to prevent the
chain from slipping off. Similar flanges D³ and Care provided upon the
wheels D and C respectively.
In order to displace the chain laterally when it is desired to shift it from the
wheel C to the wheel D) or vice versu, a striking fork H is provided carried upon
an inclined pin or guide J clamped to the chain-stay K. The striking fork J
is connected by links J¹ to a hand-lever J pivotted to the frame of the machine
near the steering-head, the links being themselves connected to the rear
portion of the frame by a short link J.
Pivotted to the striking-fork H is an arm L carrying a jockey pulley L'
which rides upon the underside of the chain, and a spring L2 which connects the
lower extremity of the arm L with the striking fork H causes the jockey pulley L'
to press downwards and thus take up any unnecessary slack in the chain.
The operation of the device is as follows, supposing the gear to be in the
position shown in Figures 1 and 2, that is to say the chain is driving the small
toothed wheel C:-
If the hand-lever J2 is moved forward in the direction of the arrow in Figure 1
a downward push is communicated to the lower link J and through it to the
striking fork H; the latter consequently slides down on its guide and owing
to the inclination of the guide, is caused to move laterally carrying the chain
with it. As the wheel D rotates the wedge face 12 of the projecting portion
engages with the chain and moves it radially outward. The lateral movement of
the chain is maintained whilst this is occurring so that the chain moves along the
teeth of the wheel 1) and finally runs upon those teeth in a position adjacent to
the flange D³.
It will be readily seen that by reversing the motion of the hand lever J the
lateral displacement of the chain will take place in the opposite direction, the
striking fork H moving up its inclined guide J and placing the chain in such a
position that as the wheel D revolves the chain will drop off at the gap adjacent
to the wedge face D2 and gear with the smaller wheel C.
To facilitate the change from one toothed wheel to the other the distance
between the last or broadest tooth on the projecting portion and the tooth of the
smaller wheel C with which the chain next gears is arranged to be equal to the
pitch of the chain.
Although in the example herein described and illustrated a single broad
wheel G is described as gearing with a pair of co-axial and narrow wheels C
and D, it is to be clearly understood that there may be three or more of these
narrower wheels, each one having the projection for shifting the chain from the
next smaller wheel.
Where two sets of these change wheels and chain are employed the necessary
means for shifting the chain would be provided in connection with one or both
I

page_text: pairs of wheels, but where practicable I prefer to so arrange the parts that the
slant of the chain when moved over at one end causes it to automatically mount
the appropriate wheel at the other.
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 change speed gear a wheel such as D) having a mutilated side face
for the purpose of mounting the chain on to the teeth substantially as described.
2. In a change speed gear the combination with two toothed wheels the larger
of which has a side recess with a gradual incline at one end and a sudden drop
at the other of a chain capable of moving from one to the other and a striking
fork all combined and operating substantially as and for the purpose described.
3. In a change-speed gear the combination with two or more co-axially
mounted toothed wheels of a driving chain and mechanism for laterally shifting
the wheels or the chain so that the chain is shifted from one wheel to the other.
4. In a change-speed gear the combination with a toothed wheel of a larger
toothed wheel mounted co-axially with it and having a projecting portion which
overhangs the teeth of the smaller wheel for the purpose described.
5. In a change-speed gear the combination with a toothed wheel of a larger
toothed wheel mounted co-axially with it and having teeth which gradually in-
crease in breadth substantially as described.
6. In a change-speed gear the combination with a toothed wheel of a larger
toothed wheel mounted co-axially with it and having teeth which gradually
increase and suddenly decrease in breadth substantially as described.
7. In a change-speed gear the combination with a toothed wheel C of a larger
toothed wheel D D 12 arranged and operating substantially as described.
8. In a change-speed gear the combination with two or more co-axially mounted
toothed wheels of a chain capable of being moved laterally off the teeth the whole
adapted to operate substantially as and for the purpose described.
9. In a change-speed gear the combination with a driving chain of a striking
fork and a spring-controlled jockey pulley substantially as described.
10. The complete change-speed gear for a cycle substantially as described or
illustrated in Figures 1 and 2 of the accompanying drawings.
Dated this 9th day of June 1900.
C. M. LINLEY,
Boult, Wade & Kilburn,
Agents for the Applicant.