Improvements in Means for Attaching the Crank Axles and Pedal Spindles to the Cranks of Cycles, Motor-cars, or similar Vehicles.
Year: 1897

page_text: Date of Application, 7th May, 1897,
Complete Specification Left, 7th Feb., 1898-Accepted, 7th May, 1898
PROVISIONAL SPECIFICATION.
Improvements in Means for Attaching the Crank Axles and Pedal
Spindles to the Cranks of Cycles, Motor-cars, or similar Vehicles.
ROOKES EVELYN BELL CROMPTON, of. Mansion House Buildings, London,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to an improved means by which the cranks are attached to
the crank axles of cycles, motor cars or similar vehicles; in place of the method
which is at present usually adopted of attaching these cranks by keys or by cotter-
ing arrangements I make the projecting ends of the axle or spindle on which the
crank is to be fixed in the forin of cones and on these coned ends I form several
key ways in the following manner. After the cones have been formed and the
cranks have been bored out with tapered holes to fit accurately on to these cones
I bore out several holes corresponding with the number of key ways which I
desire to have; the drill to form these holes must be so pointed that the centre
line of the hole corresponds accurately with the surface line of the cone, so that one
half of each hole is bored out of the male coned end, and thus forms a key way in it,
and the other half of the hole is bored out of the material of the crank. Into each
pair of key ways thus formed cylindrical keys made of hardened steel wire can be
readily and accurately fitted. Care should be taken that the drill is so directed
that the cylindrical keys lie parallel to the coned surfaces. In order to hold the
crank in position on the coned end of the spindle I provide a screw and nut at the
end of the latter the nut being so formed as to fit wholly or partly into a counter-
sunk recess provided for it in the outer surface of the crank, so that the nut need
not project at all, or only slightly from the outer face of the crank. It will be seen
that any wear that takes place either on the surface of the cone itself or in the key
ways or in the cylindrical keys, can be taken up by the one action of tightening
the nut and thus forcing the crank further up the cone. By this method of con-
struction I obtain the advantage of readily and cheaply fitting a considerable
number of small keys and thus avoid the necessity of using the extra material
at this portion of the crank necessitated by the large single key ways or cotter
holes that are usually provided. By my invention I also greatly facilitate the
fixing and removing of the cranks. In some cases I use the same method of..
attachment of the pedal spindles to the outer ends of the cranks.
T
0.
1007

page_text: Improvements in Means for Attaching the Crank Axles and Pedal
Spindles to the Cranks of Cycles, Motor-cars, or similar Vehicles.
I, ROOKES EVELYN BELL CROMPTON, of Mansion House Buildings, London,
Electrical 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:-
My invention relates to improved means by which the cranks are attached to
the crank axles of cycles, motor cars and similar vehicles or for other purposes
where it is desired to use cranks not exceeding 2 lbs. in weight and which must
be easily detachable. In place of the older methods of attaching these cranks to
their spindles by keys or by cotters I make the ends of the spindles on which the
cranks are to be fixed in the form of a cone and in these coned ends I cut key ways.
Figures 1 and 4 show a plan sectional view and Figures 2 and 5, a side elevation
and Figure 3 shows a side section of a portion of a crank attached to a spindle.
A is a spindle revolving in ball bearings within the chamber B. C is the coned
or tapered end of the spindle on to which the crank D is fitted as shown on the
sectional views Figures 1 and 4. E, 1 show key ways formed on the cone surface
into which cylindrical keys are fitted. I is a set screw which is screwed into the
end of the spindle so as to bear against the recess H in the crank thus forcing the
crank tightly onto the coned end of the spindle.
In Figure 4 I show a similar arrangement, but in this case instead of the set
screw being employed, the end of the spindle is screwed with a male thread and
a nut G engaging with this screwed end takes the place of the set screw F.
In order to form the key ways E, E, easily and correctly I employ the following
device. I drill out these key ways with a twist or other suitable drill which I
guide correctly by a jig plate or template which is screwed on to the threaded ends
of the spindle in place of the set screw F or nut G. This jig consists of a cylin-
drical portion which fits tightly into the recess H and has the requisite number
of holes corresponding to the desired number of key ways, these holes being so
placed and inclined as to form prolongations of the key ways.
Thus the holes serve to guide the drill in the correct direction so that one half
of the hole is in the cone of the spindle and the corresponding half is in the crank
boss. Although I have shown four key ways as a convenient number to employ
I do not confine myself to this number as in some cases I find a smaller number
sufficient but wherever for purposes of lightness and neatness it is required to make
the crank bosses as small as possible I prefer to use several keys of small diameter
in preference to fewer keys of larger diameter, as the crank boss is less weakened
by the employment of the large number of small key ways.
Figures 6, 7, 8 and 9 show in sectional and side views the same form of coned
attachment for the pedal end of the cranks, in this case it is not always necessary
to employ the keys as the slope of the cone which I have adopted namely 17" in 12",
is found in practice to be sufficient to hold the pedal spindle firmly in position
without the use of such key ways but I can use any desired number of such key
ways which can be drilled and made in exactly the same way as the key ways
previously described for the attachment of the larger end or boss ends of the
cranks.
The screw threads for the spindle ends and pedal spindle ends may in some cases
be made left hand threads so as to be self tightening in the direction of rotation.

page_text: 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 claim is:
1. The combination of parts for crank or pedal attachments consisting of a coned
end of the spindle in combination with key ways so placed on the coned surface
that the tightening of the set screws or end nuts tightens the crank not only on
the cone but also on the key ways, substantially as set forth.
2. In bicycles, or tricycles wherever cylindrical key ways are used I claim the use
in combination with this form of crank attachment of the tool herein described by
means of which these key ways can be cheaply and accurately formed, substantially
as set forth.
WM. BROOKES & SON,
55 and 56, Chancery Lane, London, Agents for the Applicant.