Improvements in the Fixing of Cranks or Rocking Arms to Shafts specially adapted for Cycles.
Year: 1894

page_text: Date of Application (in United Kingdom), 13th Aug., 1894
Complete Specification Left, 13th Aug., 1894-Accepted, 23rd Mar., 1895
Improvements in the Fixing of Cranks or Rocking Arms to Shafts
specially adapted for Cycles.
I, KARL FROMHOLD LAGERGREN, Grefthuregatan 83, Stockholm, Sweden,
Cashier, 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:-
The usual mode of fixing the pedal crank of a cycle to the axle consists in
fitting a taper bolt or cotter in a transverse groove in the axle, this bolt traversing
the head of the crank and being retained by a nut, on the end of the axle.
The great weakening of the axle produced by this way of fixing has the
inconvenience that the axle is often broken off at the transverse groove.
My invention has for its object to prevent this inconvenience, and, at the same
time, to produce a more secure connection between the axle and the crank.
In the accompanying drawings
Figure 1 shows this arrangement in side elevation, while Figures 2 and 3 show
sections taken respectively on the lines A B of Figure 1 and CD of Figure 2.
Through the crank head h is made an openings for the key k. This opening is
somewhat prolonged in the direction of the crank for facilitating the eye of the
crank clasping the axle more securely. In the axle made a corresponding groove
or recess for the key k; this groove either extends to the end of the axle as an
ordinary key groove or as shown in Figure 2 terminates near the end of the axle
so as to leave a portion which prevents the key from shifting in the longitudinal
direction of the axle.
The key is pressed into its groove or recess and against the axle by means of a
taper bolt or cotter crossing the key and extending through the crank-head.
The bolt or cotter bis retained either by a pin or fork in or on its smaller end or
as shown on the drawing (Figures 1 and 3) by a nut on its threaded end. When
tightening the nut the eye is pressed around the axle thereby securing a very
strong connection between the axle and the crank; at the same time the slight
reduction of the cross section of the axle leaves it substantially in possession of its
full strength.
groove
For a complete locking in the longitudinal direction of the axle a groove may
be made on the outer side of the key k as shown in Figure 2 in which
fitted the taper bolt or cotter b; or the key k may be provided with projections
for the ends (Figure 4) these projections abutting against the outer and inner side
of the crank.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is ;-
1. For fixing a crank or rocking arm on its shaft or axle a key extending along
the shaft is pressed into a groove or recess in the shaft by means of a taper bolt
or cotter crossing the key and passing transversely through the crank head.
2. For fixing a crank or rocking arm on its shaft in the manner stated in the first
claim the employment of a slot or opening such as s extending in the longitudinal
direction of the crank whereby at the tightening of the nut on the taper bolt or
cotter situated behind the key a tension or contraction of the crank head takes
place so that the shaft is securely clasped.
3. In apparatus for fixing a crank or rocking arm on its shaft or axle the
combination with a key such as k partly in the crank and partly in the axle of a
taper bolt or cotter substantially as and for the purpose described and illustrated
in the accompanying drawings.
4. In apparatus for fixing a crank or rocking arm on its shaft or axle the
combination with a key such as k partly in the crank and partly in the axle and a
taper bolt or cotter of projections such as cn the key substantially as and for the
purpose described and illustrated in the accompanying drawings.
Dated this 13th day of August 1894.
W. P. THOMPSON & BOULT,
Agents for the Applicant.