Improvements in Extension Cranks or Levers.
Year: 1894

page_text: Date of Application, 14th Aug., 1894-Accepted, 6th Oct., 1894
COMPLETE SPECIFICATION.
Improvements in Extension Cranks or Levers.
I, THEODORE FREDERICK BOURNE, of the Village of Edgewater, in the
County of Richmond, State of New York, United States of America, Solicitor
of Patents, 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 :-
My invention pertains to cranks more particularly used in treadle mechanisms,
such for instance as in the driving mechanism of bicycles, tricycles and similar
vehicles, and it has for its object to permit the crank to be extended from its
normal length or condition, and then shortened, and vice versa, at the will of the
user or rider.
The invention consists in a crank or lever comprised in two parts, one part
extensible on the other, and a lock to hold said parts together, one of said parts
having lateral motion relatively to the other to enable the parts to be unlocked to
permit one part to be moved longitudinally of the other.
The invention also consists in a crank or lever made extensible or in two parts,
one part being adapted to slide longitudinally of the other, one of said parts
having a pin or projection to enter one or more corresponding recesses in the other
part to hold said parts from longitudinal movement relatively to the other, a spring
to hold said pin or projection in said recess, one of the parts of said crank having
lateral movement relatively to the other part to disengage said pin from said recess
or socket to permit one part to move longitudinally of the other.
The invention also consists in the combination of the above mentioned parts
with a spring arranged to normally hold said pin or projection in said recess, and
yet allow said parts to move to release said pin or projection from the corresponding
registering recess.
The invention further consists in the novel details of improvement and the
combinations of parts that will be more fully hereinafter set forth and then pointed
out in the claims.
Reference is to be had to the accompanying drawings forming part hereof,
wherein,
Figure 1 is a partly broken side view of my improved crank, in the horizontal
or driving position, one side of the crank being removed to show the driving
mechanism,
Figure 2 is a cross section thereof, on the plane of the line 2, 2, in Figure 1,
Figure 3 is a side view similar to Figure 1 of the crank in its normal or short
condition, but in position to be lengthened,
Figure 4 is a corresponding view, showing the crank lengthened,
Figure 5 is a similar view, but showing the crank in position for shortening,
Figure 6 is a detail of a modification,
Figure 7 is a detail of a stop,
Figures 8 and 9 are details of modifications,
Figures 10 and 11 are details of springs,
Figure 114 is a detail view showing the application of the spring illustrated in
Figure 11, and
Figure 12 is a detail of another modification.
In the following description it will be assumed that the crank drives in the
direction of the arrow in Figure 1, while in Figures 3, 4 and 5 the crank is in

page_text: parts in the several views, the numeral 1 indicates the crank, which is made
extensible, that is to say, is made in two parts one movable longitudinally of the
other. The part 2 of the crank is shown provided with an aperture 1ª to receive a
suitable shaft to which it may be locked or keyed, or secured to the shaft in any
other desired manner, the part 3 of the crank being carried by the part 2 and
movable longitudinally thereof. The part 2 of the crank is shown provided with a
longitudinal bore or recess 4 extending from the outer end inwardly a suitable
distance, and the part 3 enters said bore and slides freely therein. In Figure 2
the part 3 of the crank is shown rectangular in cross section, and the bore 4 is
correspondingly shaped, whereby the part 3 is kept from turning in the part 2
under the torsional strain put upon part 3 when pressure is applied to pedal 5
whose shaft 6 is suitably secured to the sliding part 3 of the crank. But the
parts 2, 3 of the crank may have other cross section, or be otherwise suitably
arranged, to prevent one part from turning in or on the other on its longitudinal
axis, as by a spline and feather between said parts. The end 7 of the part 2 is
shown rounded whereby said part may have a pivotal action in bore 4 of the
part 2 of the crank. The part 3 of the crank is shown provided with a web b,
to engage the end of part 2 of the crank when the parts are in the shortened
position which limits the inward movement of part 3, and takes up part of the
down thrust in pedaling. The forward part of bore 4 in the part of the crank
is shown wider than the part 3 at that point whereby said part 3 may have lateral
movement, at its outer portion, within bore 4, as shown in Figures 3 and 5. The
inner portion of the part 3 of the crank, at its end 7, is widened or provided with
a toe or projection 9, that rides against one side or wall 2 of the bore 4 in part 2.
This toe or projection 9, therefore, in conjunction with the opposite side 10 of the
part 3, acts as a pivotal point for the part 3 to permit it to turn or move laterally
at its outer part, while at the same time preventing lateral movement of the end 7
of the sliding part of the crank. It is evident that a pivotal action can be
allowed the inner end of part 3 of the crank otherwise than as above explained,
suitable means therefor being shown in Figure 6, wherein the side wall or walls
of part 2 may be provided with a slot or slots 11, in which a pin 12 carried by the
part 3 works. The pin and slot act to limit the longitudinal movement of the
sliding part 3 in the part 2 of the crank.
In Figures 1 to 5 I have shown a stop 13 located in the bore or recess 4 of the
part 2 of the crank, that lies in the path of the enlargement, toe or projection 9 of
the sliding part 3 of the crank, so that when the toe or projection 9, in its forward
movement strikes the stop 13 it will limit the outward movement of the part 3 of
the crank. The stop 13 may be made integral with the part 2, but I find it
convenient to make said stop in the form of a cross bar having its ends located in
recesses 14 in the sides of the part 2 of the crank. While the stop 13 may be
held in place by riveting I may provide said stop with an offset 15 that rests against
the inner wall of the bore 4 of the part 2 of the crank to prevent said stop from
slipping out of apertures 14.
Instead of using toe 9 and stop 13 to limit the forward movement of sliding
part 3 I may provide parts 2, 3, with a pin or screw and slot, as in Figure 8,
wherein part
of the crank on one side is provided with a slot 13* that receives
a pin, screw or projection 9 on the sliding part 2, or vice versa, whereby pin or
projection 9 will strike the metal at the end of slot 13" to limit the forward
movement of the part 2 of the crank. But other suitable devices may be used for
this purpose.
For convenience of manufacture I have shown the bore 4 in the form of a
channel or groove in one side on the part 2 of the crank, and provided with a
cover 16 that may be riveted on the part 2 of the crank or fastened by screws 16*
as shown in Figure 2. The side or cover 16 may be removed to adjust or
clean the parts within the bore 4. But it will be understood that the
parts 2 and 3 of the crank may be placed together in any suitable manner to
permit one part to slide longitudinally of the other, and yet prevent rotation or

page_text: turning of one part within the other, and plate 16 may have a recess 14 to receive
stop 13.
To lock the parts 2 and 3 together so that they will be firm to resist the driving
power, and yet permit them to be unlocked when desired I utilize a lock to hold
said parts together. For this purpose I have shown the part 2 of the crank as
provided with a pin or projection 17 that enters a corresponding recess or socket 18
in part 13 (Figures 1 to 5). There are two or more sockets 18 in part 3, corre-
sponding in distance apart to the sliding movement allowed the part 3, so that
when pin 17 is in one recess 18 the crank will be in its short or normal position,
and when pin 17 is in the other recess 18 the part 3 will be in its lengthened or
extended position, as shown in the drawing.
In Figure 91 have shown the pin 17 as carried by the sliding part 3 of the
crank and the sockets 18 in the wall of the part 2.
2 as
To normally keep the pin or projection 17 in a socket 18 I provide a spring 19
to hold part 3 normally against wall 2b of the part 2 of the crank. Said spring 19
is shown located within the forward part of bore 4 in the part 2, which spring
bears against the sliding part 3 of the crank, and against wall 2ª of part
shown. By preference I secure spring 19 to the part 3 of the crank, as by a rivet,
screw or the like 20, or by other suitable means, and thereby cause the free end of
said spring to bear with suitable force against wall 2" to normally hold one side of
the sliding part of the crank against wall 2b of part 2 of the crank, to thus hold
pin 17 in a recess 18. This is the normal driving position of the parts, and as
shown in Figure 1 the side 3ª of part 3 of the crank exerts pressure against
wall 2° of part 2, while the toe or projection 9 on the part 3 hears against wall 2ª
of the part 2, whereby the inner end of part 3 is held from tilting within bore 4.
Pressure now exerted on pedal 5 in the direction of the arrow in Figure 1 binds
the parts 2, 3, together and pin 17 being normally in the socket 18 prevents the
part 3 from sliding. The spring 19 should be of sufficient tension or strength to
resist the normal weight of the rider's foot, when the crank is on the up-stroke, so
that pin 17 will normally remain in the socket 18. Therefore with the above
described arrangement the parts will under normal conditions remain in the
positions shown either in Figure 1 or Figure 4, or in the shortened or lengthened
condition.
When it is desired to lengthen the crank the latter is allowed to descend to its
lowest position and when it rises on the up-stroke extra downward pressure is
exerted by the rider on the pedal, sufficiently to overcome the resistance of spring 19,
whereupon the sliding part of the crank will be tilted in bore 4 to release pin 17
from socket 18, whereupon the sliding part of the crank under the influence of
the downward pressure will slide outwardly or downwardly from the position
shown in Figure 3 to that shown in Figure 4, the toe 9 thereupon encountering
stop 13 to limit the outward movement of part 3 of the crank. Pin 17 and
socket 18 will now be in line, and as the downward pressure on the pedal is
decreased spring 19 will press back the part 3 of the crank, and thus cause pin 17
to enter the corresponding socket 18 whereupon parts 2 and 3 will be locked in
their extended positions, as in Figure 4. The crank can now be used in its
lengthened position to develop greater power on its axis. When the crank is in a
vertical position downward pressure will not release the pin 17 from its socket 18.
When it is desired to shorten the crank the rider waits until the crank has risen on
the up-stroke to an angle above a horizontal plane, and near the vertical (see
Figure 5). Downward pressure on the pedal when the crank has reached the
proper upper angle will cause part 3 to tilt backwards to release the pin 17 from
socket 18, whereupon the downward pressure on the pedal will cause the part 3 to
slide inwardly until web b abuts against the end of the part 2, whereupon spring 19
will press part 3 against wall 25 of part 2 to cause pin 17 to enter the corre
sponding socket 18, as in Figure 1. It will be understood that the crank can
continuously rotate in the shortened or extended condition, and that the rider can
lengthen or shorten the crank when desired by merely exerting sufficient force on

page_text: the pedal, when the crank has arrived at the proper angle, to overcome the normal
resistance of spring 19, and release the lock.
In Figure 10 the spring 19 is in the form of a flat spring, which may be suitably
shaped and bent, and provided with an aperture 19%, to receive the rivet or
screw 20, but it is evident that spring 19 can be secured to the wall 2ª of part 2,
so that part 3 can slide against said spring as in Figure 11. When spring 19 is
secured to part 2 I may provide it with cars 13, as in Figure 11, which enter the
sockets 14 in the wall of the crank and in cover 16. In this case the inner end of
spring 19 acts as a stop to limit the outward motion of part 3 of the crank.
Instead of providing part 2 of the crank with bore 4 I may provide part 3 with
said bore so it can receive and slide on part 2, as in Figure 12, the pin 17, socket 18
and spring 19 being arranged substantially as and for the purposes before specified.
In this case the toe or projection 9 would be carried by and with bore 4 of the
part 3 to enable the necessary pivotal action between parts 2 and 3 to release the
pin 17 from its socket 18 to take place.
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 :-
1. A crank or lever comprised in two parts, one part extensible on the other and
adapted to have lateral motion relatively to the other, and a lock for holding said
parts together and arranged to be unlocked by the lateral movement of one of said
parts, substantially as described.
2. A crank or lever made in two parts, one part being extensible on the other,
one of said parts adapted to have lateral movement relatively to the other, a lock
to hold said parts together, and a spring to act with said lock and against the lateral
movement of one of said parts of said crank.
3. A crank or lever made in two parts, one part extensible on the other, one of
said parts adapted to have lateral movement relatively to the other, a pin or
projection rigidly carried by one of said parts, the other part having a recess or
socket to receive said pin or projection, and a spring to hold said pin or projection
in said recess or socket and to act against the lateral movement of one of said
parts.
4. A crank or lever made in two parts, one part having a rectangular bore to
receive the other part, the latter part being rectangular in cross section, a pin or
projection carried by one part to enter a socket or recess in the other part and a
spring to hold said pin or projection in said recess or socket, one of said parts
adapted to have lateral motion relatively to the other to permit said pin to be
withdrawn from said recess or socket.
5. A crank or lever made in two parts, one part having a bore opening at its
outer end to receive the other part, said bore being wide enough to permit said
other part to have lateral motion, a lock for holding said parts together, and a
spring to act with said lock and against the lateral motion of said movable part of
the crank.
6. A crank or lever made in two parts, one part having a bore, the other part
being a sliding bar in said bore, a stop within said bore, a toe or projection on the
sliding bar near its inner end to ride against the wall of the other part, said bore
being wide enough in one direction to permit the sliding bar to have a pivotal
motion within said bore, a pin or projection carried by one of said parts to enter
a recess or socket in the other part, and a spring carried by the sliding part near
its outer end to hold said pin in said recess or socket.
7. A crank or lever made in two parts, one part extensible on the other, the
sliding part having a web to bear against the end of the other part to limit the
inward movement of said sliding part, means for locking the parts of the crank in
two positions one of said parts having lateral movement relatively to the other to
permit said part to slide longitudinally of the other.
8. A crank or lever made in two parts, one part having a longitudinal bore to

page_text: receive the other part, a stop composed of a cross bar having its ends located in
sockets in the walls of said bore, a projection on the sliding part of the crank to
engage said stop, a lock to hold said parts of the crank together, and a spring
to hold said parts in their locked position.
9. In a bicycle or other cycle, a crank comprised in two parts, one part having
a bore, the other part being a bar extending longitudinally in said bore and adapted
to slide therein, a lock to hold the parts together in the driving position, and
means to permit the crank to be lengthened by the pressure of a person's foot.
upon the sliding bar when the crank extends in a downwardly and rearwardly
inclined position, and means to permit the crank to be shortened by the pressure of
a person's foot upon the sliding bar when the crank extends in an upwardly and
rearwardly inclined position.
10. A crank comprised in two parts, one part having a bore, the other part being
a sliding bar located in said bore, said bore being wider in one direction than said
sliding bar, a stop carried by the part having the bore, a toe or projection on the
sliding part to engage said stop, a spring carried by said sliding part and bearing
against the other part, and a pin or projection carried by one of said parts to enter
a recess or socket in the other part, said pin or projection and the recess or socket
being located on the driving side of said crank.
11. A crank or lever made in two parts, one of said parts having a bore to
receive the other part and being also provided with a stop, a toe or projection on
the sliding part to engage said stop, a lock for holding said parts together and
means for releasing said lock.
Dated this 14th day of August 1894
ALLISON BROS.,
Agents for the Applicant.