An Improved Method of Mounting Cranks, Pulleys, or similar Objects on Shafts or Spindles, Particularly Applicable to Velocipedes.
Year: 1889

page_text: Date of Application, 15th Jan., 1889
Complete Specification Left, 15th Nov., 1889-Accepted, 21st Dec.,
1889
PROVISIONAL SPECIFICATION.
An Improved Method of Mounting Cranks, Pulleys, or similar Objects
on Shafts or Spindles, Particularly Applicable to Velocipedes.
We ISAAC WATTS BOOTHROYD, manager, and PHILIP LOUIS RENOUR, engineer,
both of 47 Farringdon Road, in the city of London, do hereby declare the nature of
our said invention to be as follows:-
The object of this invention is to mount cranks and pulleys and similar objects on
shafts and spindles in such a way as to render them readily detachable. Hitherto,
where it has been sought to attain this object, the key or feather used for the purpose
has always had a tendency to stretch the boss of the crank or pulley in such a way as
to leave it binding on one side only, and thereby leaving the spindle unsupported
where it is cut away by the keyway. We obtain our object in the first place by
driving a taper or conical key right through the middle of both boss and spindle; in
the second place the latter is either conical (without too great a taper) or else threaded,
the inside of the boss being made to correspond. Where the spindle is conical, the
clearance in the transverse hole is so arranged, that the key partly takes the driving
strain and partly relieves itself of the same by forcing the boss to a higher part of the
spindle, which will thus be gripped all round. Where the spindle is threaded it is
also slit longitudinally on one side of the key hole; the taper key will then expand
the spindle and make it fit the inside of the boss tightly. The small end of the key is
preferably threaded and the key drawn up by screwing it into the solid part of the
boss. When the key is withdrawn the crank, pulley or other similar object can be
readily wound off the shaft or spindle.
Dated this 15th day of Janua 1890
POPPLEWELL, COLTON & Co.,
Agents for the Applicants.
COMPLETE SPECIFICATION.
An Improved Method of Mounting Cranks, Pulleys, or similar Objects
on Shafts or Spindles, Particularly Applicable to Velocipedes.
We ISAAC WATTS BOOTHROYD Manager and PHILIP LOUIS RENOUF Engineer both
of 47 Farringdon Road in the City of London do hereby declare the nature of our
said invention and in manner the same is to be performed to be particularly described
and ascertained in and by the following statement :
-
The object of this invention is to mount cranks and pulleys and similar objects on
shafts and spindles in such a way as to render them readily detachable.
Hitherto where it has been sought to attain this object the key or feather used for
the purpose has always had a tendency to stretch the boss of the crank or pulley in
such a way as to leave it binding on one side only and thereby leave the spindle
unsupported where it is cut away by the keyway. We attain our object by driving a
taper or conical key right through the middle of both boss and spindlo, the latter is
either preferably-conical or threaded, the hole in the crank or pulley being made to
correspond, in the former case the action of the key will be to draw the crank or
pulley on to the conical part of the spindle, in the latter case the threaded part of the
spindle is expanded so as to fit the boss tightly. The keys are preferably cylindrical
at each end and the bosses formed with corresponding cylindrical holes the middle part
of the keys being tapered to ensure of expansive action only on the spindle and not on
the boss.
By making these cylindrical parts of suitable lengths a sufficiency of draught is
ensured to allow the keys to be withdrawn and replaced without their being altered or
refitted. The keys are either merely driven home, in which case the smaller end

page_text: should protrude beyond some open part of the boss or recess in the boss of the crank
so that it can be readily hit back when the crank has to be detached, or else the smaller
end is screwed into the boss or is pulled up with a nat. The keyhole is sometimes
drilled at an angle other than a right angle or diagonally to the direction of the spindle
or shaft thus offering greater surface and increasing the power of resistance of both
spindle and key to the shearing strains they are submitted to we preferably drive the
koys through the cranks in a longitudinal direction as shewn in the drawings thus
obviating all danger of stretching or breaking the boss. Except in the case of the
conically ended spindle we find it of advantage to provide the end of the spindle with a
split extending into the keyhole. It is in all cases preferable to have the bosses made
of harder and less elastic material than that of the spindle or shafts.
Referring to the accompanying drawings
Figure 1 shews a crank B fitted over a slightly tapered spindle or shaft A and pro-
vided with the key C. The keyhole in the spindle has sufficient clearance along its
inner side, so that when the key is driven up the crank is drawn tighter on to the
conical spindle.
In Figure 2 D is the boss of a pulley chain wheel or the like and the key Ę is
driven through diagonally. B is a crank and a key the lesser end of which is
screwed into a corresponding hole. The end of shaft A is shewn split.
Figure 3 shows the key passed into a recess in crank B such as are frequently
stamped out of bicycle cranks for the purpose of lightening them the key goes through
the shaft A at an angle so as to render it very easily accessible.
When it has been
driven into its place it is rendered secure by the nut F.
To detach the cranks or pulleys the keys have to be removed by unscrewing them or
hitting them back, the cranks pulleys or the like are then readily wound off. Where
such cranks or pulleys are mounted on cylindrical surfaces it is necessary to make
them fit very tightly to prevent looseness and in withdrawing them when they are
tightly fitted the holes frequently become bell-mouthed and the fit destroyed whereas
objects mounted by our method are very readily removed and any looseness of fit
remedied by the expansive action of the keys.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :
First A taper or conical key driven through the boss of a crank or pulley or
similarly mounted object and through the spindle or shaft on which such object is
mounted substantially as described.
Second-The combination shewn in Figure 1 of the boss of a crank pulley or
similar object bored out conically and a conical surface on a shaft or spindle with a
taper or conical key passed through both parts in the manner and for the purpose
described.
Third-The method of screwing a crank pulley or similar object on a shaft or
spindle and securing the same by a taper or conical key in the manner and for the
purpose described.
Fifth-
-The taper or conical key C in Figure 2 screwed into the crank B.
Sixth-The taper or conical key C in Figure 3 passed through both crank and
spindle and secured by the nut F.
Seventh-The key E in figure 2 and the key O in Figure 3 passed through both
boss and shaft diagonally for the purpose described.
Eighth The taper or conical key passed through the centre of the boss of a crank
in a longitudinal direction substantially as described.
Ninth The combination of a taper key C such as shewn in Figure 2 with a split
end of a shaft or spindle such as A capable of expansive action as herein described.
Dated this 15th day of November 1889.
POPPLEWELL, COLTON & Co.,
17 & 18, Southampton Buildings, W.C., Agents for the Applicants.