An Improved Variable Friction Gear for Velocipedes.
Year: 1897

page_text: Date of Application, 15th June, 1897-Accepted, 12th Feb., 1898
COMPLETE SPECIFICATION.
An Improved Variable Friction Gear for Velocipedes.
I, HEINRICH MEYER, of 154A, Kopenickerstrasse, Berlin, Germany, 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 a variable friction gear for velocipedes and it consists in
using a friction disc which is operated by the pedal cranks and which causes friction
rollers fitted on the end of spindles or shafts to revolve and thereby, through the
medium of bevel gearing, to rotate the hub of the driving wheel. Mechanism is
also provided whereby the gear of the velocipede can be varied by simply shifting
the friction rollers.
And in order that my said invention may be properly understood I have hereunto
appended an explanatory sheet of drawings whereon:-
Fig. 1 shows in side view a bicycle having my invention applied thereto.
Fig. 2 is a part sectional plan of the driving gear drawn to an enlarged scale.
Fig. 3 is a view showing the mechanism for varying the speed.
Fig. 4 is a section taken through the gear casing C and showing the gearing
therein. The section is taken on the line x-y Fig. 3.
Referring to the drawings:-
s is a friction disc which is mounted on the pedal axle t and drives the two friction
rollers arranged one at each side of the disc. Motion is transmitted from the disc,
by friction, to the rollers ?, ?, and through them to horizontal spindles w arranged
within each horizontal tubular back stay A of the machine. Each spindle w (one
only is shown at Fig. 2,) actuates the bevel gearing kk and thereby rotates the hub
of the driving wheel B. U is a gimbal or universal joint and n a tubular coupling
piece into which the spindle w fits telescopically. The whole of the spindle w or
that part of it which fits in the coupling piece n is of square section so that whilst
it is capable of revolving the coupling it is also at the same time, capable of a free
longitudinal movement therein.
The bearings of the rollers slide on blocks ? which are connected together in
tension by means of springs f, f¹. The action of these springs tends to pull or press
the rollers, 7, against the surfaces of the disc 8. The blocks constituting the
bearings move in a plane which is perpendicular to the surfaces of the disc s, and, as
the casing c is rigid and not acted upon by the springs, the pressure of the rollers on
both sides of the friction disc is the same. To facilitate the movements of the
sliding blocks small balls or rollers i are arranged at their under sides.
The mechanism for varying the gear is shown at Figs. 1, 3, and 4. It consists of
a lever h which is forked so as to partly surround the upper horizontal stay of the
frame and is fulcrumed on a pivot pin b. Secured to the lever a quadrant h¹ to
which a chain a is attached. The lower end of the chain is secured to the quadrant d¹
of the tumbler d. e is a spiral spring also attached to the tumbler which latter is
mounted on a pivot c. e¹ is a plate spring fitted in connection with the tumbler and
downwardly bent ends. L is a double rack having on its upper branch inclined
teeth m¹ and on its lower branch teeth m² inclined in one direction and teeth m³

page_text: inclined in the opposite direction. This rack is attached at to the link E and at 1,,
to the sliding blocks of the rollers r. 0, 0¹, are the two pawl-shaped arms of an anchor
which is connected with an eccentric strap fitted round an eccentric q made in one
with the crank axle t. g is a spring which when the pawls are released as hereinafter
described always brings them back to the horizontal position clear of the rack as
shown at Fig. 3.
It is evident that by merely moving the rollers r, r, towards the centre of the disc s
the speed of the gearing will be reduced whilst by moving them towards the
periphery of said disc the speed will be increased.
In order to increase the speed gear the lever h is pulled over from the mid-position.
in the direction of the arrow 8 and as a result the tumbler & turns on its pivot c,
against the action of the spring e, and causes the back end of the spring e² to depress
the pawl o¹ and force it into engagement with the teeth m³ of the rack. As a con-
sequence, owing to the reciprocating movement of the anchor with its pawl o¹ caused
by the rotation of the eccentric on the pedal crank shaft t, the rack and also the
rollers are moved backwards and consequently the speed is increased. When the
desired increase has been obtained the lever h is brought back to the mid-position so
as to throw the pawl o¹ out of engagement with the rack teeth m³ and stop further
backward movement of the rack.
To reduce the speed gear the lever is moved to the position of the arrow I
whereupon the contraction of the spring e causes the front end of the spring e¹ to
depress the pawl o and force it into engagement with the teeth m² whereupon, in
the same manner as before, the rack is moved forward so as to bring the rollers r
towards the centre of the discs and thereby reduce the speed. When the desired
reduction has been obtained the lever h is brought to the mid-position so as to release
the pawl o and stop further forward movement of the rack.
When the lever h is in the mid-position the tooth m of the tumbler & enters the
teeth m¹ of the rack and locks it in place.
It may be further stated that the bevel gears as well as the controlling mechanism,
are enclosed in tight casings and are thus protected from injury and dirt.
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
consider novel and desire to claim is :-
1. A variable friction gear for velocipedes characterized by the arrangement of the
bearings of the friction rollers at each side of the friction disc 8 upon sliding or
guide blocks p which are drawn towards each other by means of springs f, f¹, so as
to press the friction rollers against the driving dises and at the same time to obviate
lateral pressure on the casing C, substantially as herein before described with reference
to the drawings annexed,
2. The gear changing mechanism operated by the lever h consisting of a tumbler d,
spring e, spring e¹, rack Z, anchor with pawls o, o¹, and eccentric q, substantially as
herein before described and shown on the drawings aunexed.
Dated the 144L
CT
100kb
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.