Year: 1897

page_text: I, ALFRED MASON, of 19, Caledonian Road, Leeds, Music and Musical Instrument
Dealer, do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved crank movement and is more especially
intended for use in connection with chain driving gear for cycles and similar
foot driven vehicles. The object is to practically do away with the "dead points,",
and also to cause the crank end to accommodate itself more accurately to the move-
ment of the foot when pedalling. It is well known that during the upward movement
of an ordinary crank, the foot has a decided tendency to travel faster than the
crank end, so much so, that it often causes the foot to leave the pedal. Beside
this, with the ordinary crank as used on cycles and where the crank arms are
put directly opposite one another, considérable power is required to move them
through the space comprised between a few degrees before and a few degrees
after the position where the centre lines of the crank arms are in a line with the
direction of the applied power. Consequently the crank is moved through a
considerable part of its circle of movement at great disadvantage as regard
power. Now in my improved crank movement; each crank has an independent
movement, and while one pedal descends slowly, the other rises quickly. In other
words, each crank arm has a gradually increasing and then gradually decreasing
speed during each revolution, the increase of speed being greatest during the upward
stroke. In carrying my invention into effect, I employ any suitable gear whereby
is obtained a slow movement with one crank armi simultaneously with a quick
movement of the other arm. It is obvious that the movement will be of
all eccentric nature, and may be obtained by lever, or by circular, oval,
other spur
combination.
or in
As an example of
a spur wheel arrangement, I give the following example. One of the crank arms
is attached to the main driving axle. Free to revolve on the axle is the chain
wheel. To the axle is also attached a spur wheel not placed centrally but
eccentrically as regards the axis of the axle. Free to revolve at the opposite end
of the axle is the second crank arm, having attached to it a second spur wheel-placed.
eccentrically to the same extent as the other one, but in the opposite direction.
Parallel to the axle is a bracket within which runs a supplementary axle, having.
fixed at one end two eccentrically placed spur wheels connected to one another
and revolving together, the said spur wheels gearing into those attached to the.
second crank and to the first mentioned axle. At the opposite end of the supple-
mentary axle is a centrally placed spur, wheel gearing into a centrally placed spur
wheel attached to the chain wheel already mentioned. In assembling the parts
together in the first instance, I so arrange matters that the two crank arms shall
not stand at 180° as is the case with the ordinary cycle cranks. The action of the
gear is as follows:-On rotating the first mentioned crank the spur wheel
attached to the axle will also rotate and being geared into one of the two
connected and eccentrically placed wheels on the supplementary axle, will cause,
the last mentioned wheel and its fellow to revolve and rotate the other crank.,
or
wheels alone
.

page_text: The rotation of the chain wheel is effected by the centrally placed spur wheel
on the supplementary. axle gearing into the centrally placed spur wheel attached
to and revolving with the chain wheel.. The eccentric gearing of the two sets
of eccentrically placed spur wheels causes an alternate gradual quickening and
slackening of the speed of the cranks, thus when the larger radius of one wheel
is geared with the smaller radius of another, they act as two wheels of different
diameters, and the latter will revolve faster than the former: when however the
wheels have rotated, half a revolution, the relative speeds will be reversed.
Simultaneously, the larger radius of the other, of the joined and eccentrically
placed spur wheels will cause the other crank to rotate slowly at first. In this
manner the slow downward movement of one crank arm, is accompanied by the
quick upward movement of the other crank arm, thus causing the pedal attached to
at, to keep up with the riders foot as it moves upwards, instead of having a
tendency to lag behind the foot, and in this way counteracting the fault of the
ordinary crank which moves in a circle at uniform speed while the riders foot
moves during a portion of the circle of movement at an increased speed. The
placing of the crank arms at the angle mentioned also practically gets over the
dead points."
Balls and other arrangements may be used wherever necessary to reduce friction
of running parts.
L
J
1002
.
I, ALFRED MASON, of 19, Caledonian Road, Leeds, Music and Musical Instrument
Maker, 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:-
are used.
My invention relates to an improved crank movement and, although it is more
especially intended for use in connection with chain driving gear for cycles and
similar foot driven vehicles it may be employed wherever cranks
The object is to pracaly do away with the dead points, and also
to cause the crank end to accommodate itself more accurately to the movement
of the foot when pedalling. It is well known that during the up movement
of an ordinary crank, the foot has a decided tendency to travel faster than the
crank end, so much so, that it often causes the foot to leave the pedal. Besides
this, with the ordinary crank as used on cycles.and where the cranks are
put directly opposite one another, considerable power is required to move them
through the space comprised between a few degrees before and a few degrees
after the position when the centre lines of the crank arms are in a line with the
direction of the applied power. Consequently the crank is moved through a
considerable part of its circle of movement at great disadvantage as regards
power. Now in my improved crank, movement, each crank has an independent
motion, and while one pedal descends slowly, the other rises quickly. In other
words, each crank has a gradually increasing and then gradually decreasing speed
during each revolution, the increase of speed being greatest during the upstroke.
In carrying my invention into effect, I employ any suitable gear whereby is
obtained a slow movement with one crank simultaneously with. a quick movement
of the other. It is obvious that the movement will be of an eccentric character,

page_text: and
and in order to explain the invention, I make reference to the accompanying sheets
of drawings shewing one method of carrying out my invention. In these draw-
ings, Figs. 1 and 2, shew side views of the ordinary crank in two positions. Figs. 3,
and 4, are side views of my improved crank in two positions. Fig. 5 is a part
horizontal section of the whole of the parts for obtaining my improved crank
movement. Fig. 6, is a side view of one of the cranks. Fig. 7, is a side view
of the other crank. Figs. 8, and 9, are side views of the eccentrically placed
spur-wheels.
Similar letters refer to the same parts. One of the cranks a
is attached to the axle b parts of which are reduced in diameter at c and c¹. Free
to revolve on c is the chain wheel d on one side of which may be the cone e,
on the other side the race f, the race to accommodate balls between itself and
the cone g.
The cone e bears balls between itself and a race h inside the end
of the axle bearing i. To the axle is also attached the spur wheel j. The
wheel however is not attached centrally but eccentrically, so that the distance
from the axis to the pitch line is less on one side, than it is on the diametrically
opposite side. Free to revolve on el is the other crank k having attached to it a
second spur wheel also placed eccentrically to the same extent as j, but in the
opposite direction. is cupped at m to accommodate balls placed between itself
and cone screwed or otherwise attached to the extreme end of c¹. Parallel to
the axis of b is a bracket o within which runs the supplementary axle p having
fixed at one end the two spur wheels j¹ and connected to one another by screws
or in some other suitable manner so as to revolve together j¹ gearing into j
and into l. At the opposite end of p is fixed a centrally placed spur wheel
gearing into another centrally placed spur wheel r, attached to or forming part of
the chain wheel d. In order not to unnecessarily increase the tread of the machine,
the spurr may be recessed to receive one end of the bearing i. p is provided with
cones s between which and the race t at the ends of o are balls. In assembling the
parts together in the first instance, I so arrange that the two crank arms shall not
stand at 180 degrees apart, but shall be relatively to one another as shewn in Figs. 3
and 4. The action of the gear is as follows:-On rotating crank a the spur wheel j
will also rotate and being geared into will cause it (¹) and its fellow wheel
also to rotate and gearing into will rotate the other crank k. The rotation of
the chain wheel d is effected by the wheel 9 gearing into r which is attached to
the chain wheel free to rotate round c. On careful inspection and considera-
tion, of the drawings, it will be seen that the eccentric gearing of the wheels j
and ; and causes an alternate gradual quickening and gradual slackening
of the speed of the cranks. Thus when the larger radius of
is geared with the smaller radius of ₁, they will act as two wheels
of different diameters and the latter revolve faster than the former.
When however the wheels have rotated half a revolution, the relative speeds
will be reversed. Simultaneously the larger radius of will cause and con-
sequently to rotate slower. (See Figs. 8 and 9). In this manner the slow
downward movement of one crank is accompanied by the quick upward movement
of the other crank. In other words, assuming a to be pressed downwards, it will
through cause a gradually increasing rotation of j¹ and as j¹ and are connected
together in opposite directions, I will give an increasing speed to k which is
moving upwards, and will therefore cause the pedal attached to it keep up with
the riders foot as it moves upwards, instead of having a tendency to lag behind
the foot, thus counteracting the fault of the ordinary crank which moves in a
circle at uniform speed, while the riders foot moves at a portion of the circum-
ference with increased speed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
CLAIMS.
1 Providing cycles and other vehicles with aauks
اممم
Q1111 of which

page_text: ment of each arm having the essential feature of increasing in speed from a point
between the beginning and ending of its down stroke and decreasing in speed
from a point between the beginning and ending of its up stroke, substantially
as described, and for the purposes set forth in the above specification.
..
2. Constructing cranks in such manner that each arm shall have an independent
movement and a gradually increasing speed, the greatest speed being attained
during the upward movement of the crank arm, the said gradually increasing-spoed
being for the purpose, and obtained substantially as set forth in the above specifica-
tion and exemplified in the accompanying drawings.
3. In carrying into effect the preceding claims as applied to cycles and other
vehicles, the use of an axle having one crank arm attached to one end thereof,
the second crank arm being free to rotate round the opposite end and having
attached it an eccentrically placed spur wheel gearing into one of two eccen
cally placed and joined spur wheels attached to one end of a supplementary ax!c
placed parallel with the first mentioned axle, the second of the eccentrically
connected spur wheels gearing into another eccentrically placed wheel, attached
to the crank axle, the said supplementary axle having fixed to one end a centrally
placed spur wheel gearing into a centrally placed spur wheel attached to the chain
wheel and free to rotate therewith round the first mentioned axle, the whole sub-
stantially as described in the above specification, and exemplified in the accom-
panying drawings.
Dated 1 1041
100
HUGHES & YOUNG,
23, Coleman Street, London, EC., Agents for Applicant.