Year: 1889

page_text: I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I M.E. 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 crank for bicycles and other velocipedes that may be
lengthened and shortened while the machine is in motion.
The invention consists in the various features of improvement more fully pointed
out in the claims.
In the accompanying drawings::-
Fig. 1 is a sectional side elevation of the adjustable crank showing it shortened.
Fig. 2 is a similar view showing it lengthened.
Figs. 3, 4 and 5 are detail views of the parts a, b and c respectively.
The crank is composed essentially of three parts a, b and c.
111
The plate a is secured upon the axle d. To its back there is secured by screw h, a
spring e, carrying at its free end a bolt f. The bolt projects through one of a number
of openings g, of plate a. By detaching spring e and re-attaching it by different screw
holes say those marked h¹ the bolt f may be made to project through another of the
openings g in plate a. At its face the plate a is provided with a pair of rails i, that
guide a slide b.
This slide is provided with the openings k and is locked to the plate a when
the bolt projects into either one of these openings. In the slot t of slide 6 there is
secured the pin or spindle of the treadle P. The slide 6 is provided with guides
Near
between which there is placed the slide c. This slide has two foot pieces m n.
one of its ends the slide c is provided with a tapering projection or nose o bevelled at
both sides. This projection extends through a slot p that connects the openings k, k¹
of slide b.
s is a face plate secured by screw r to slide b and serving to exclude dirt.
The operation of the device is as follows:-
-
If the crank is to be lengthened from the position shown in Fig. 1 into that
1

page_text: slide c to move so that its tapering projection or nose o will push the bolt f backward
to clear plate b. Thus the positive connection between the parts a b will be broken
and the slide 6 will be carried along with slide e until the bolt is in line with
opening. The bolt will now shoot forward into this opening to again positively
connect the parts a b. The crank will now be lengthened. To shorten it the foot is
pressed upon foot piece m when the projection o will push the bolt fout of opening k.
The slide 6 will then again move with slide c until the bolt shoots into opening kl.
The extent of motion of the parts may be regulated by projecting the bolt through
either one of the openings g of plate a. This is accomplished as already described
by screwing the spring e to either of the screw holes h or h¹.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed, as communicated to me by my foreign
correspondent I declare that what I claim is :-
f
1. The combination with a crank or plate such as a carrying a spring bolt such as
of a pedal-carrying plate or slide such as having openings for the reception of said
spring bolt substantially as described and illustrated in the accompanying drawings.
2. The combination with a plate or crank such as a of slides such as b and c and
bolt the slide b carrying the pedal P and being adapted to be locked to crank a by
bolt substantially as described and illustrated in the accompanying drawings.
3. The combination with a crank or plate such as a of a slide such as 6 having
connected openings kand of a slide such as c having a projection o that enters said
openings and of a spring bolt secured to crank a substantially as described and
illustrated in the accompanying drawings.
4. The combination with a plate such as a having a series of openings g of a
slide such as 6 spring bolt such as fand slide such as c having foot pieces such as m. n.
and projection or nose o adapted to operate bolt f substantially as described and
illustrated in the accompanying drawings.
Dated this 5th dor of Merb 1880