Year: 1898

page_text: I, JOHN MOUNTGOMERY COLLINS, of 45, Bartholomew Street, Bridgeton, Glasgow,
Engineer, do hereby declare the nature of this invention to be as follows;-
This invention relates to crank driving mechanism for velocipedes and it is a
development of and improvement upon my prior invention No. 18322 dated
6th August 1897.
Under this invention the eccentric upon which the driving wheel revolves and
the driving wheel itself are made in a special manner. The eccentric is screwed
on its edge or periphery for the reception of a cup ring and a cone ring, said rings
forming a race for the balls in conjunction with an outer revolving ring made with
a groove (for the balls) on its inner periphery. This ring is provided with lugs
at intervals to which the sprocket or other driving wheel is secured in any well
known manner. The slotted cross bar, in which the crank pins work, is attached
to the driving wheel by means of screws or bolts. In order to tighten the cup
and cone rings on the eccentric the rim of the latter is split and is so made that
by driving in a wedge pin it can be opened out or expanded. The rim of the
eccentric is also made with an edge or flange for checking the cup and cone rings.
As will be seen the eccentric and the driving wheel are made in a number of
separate parts which can be easily fitted in place and also easily renewed when
damaged or broken. The parts can be easily case-hardened.
A special feature of the invention is the provision of means whereby the working
centre i.e., the centre of revolution of the hollow and solid crank shafts or spindles
can be shifted, at will, relatively to the centre of the driving wheel so as to
vary the leverage exerted by the pedal cranks. In carrying out this part of my
invention I make the bottom bracket of the velocipede larger than usual and
insert therein a revoluble sleeve or liner which may be slotted for lightness. This
sleeve, which may or may not as desired run upon ball bearings, has fitted
eccentrically within it a tube or its equivalent, or simply bearings, in which the
hollow and solid crank shafts of the driving gear revolve. The sleeve is provided
with an external rim or flange made with worm wheel teeth into which mesh the
teeth of a worm fitted on a worm shaft whose upper end is carried to or near to the
handle bar or other suitable part of the cycle and is provided with a handle
or other means whereby it can be operated.
With this arrangement, whenever it is desired to vary the leverage, all that is
necessary is to turn round the sleeve (which carries the working spindles or shafts
with it) so as to vary the distance of the working centre from, or make it coincide
with, the centre of the driving wheel.

page_text: It is to be noted that the driving wheel eccentric is arranged with its longest
radius directly or nearly directly downwards in a vertical line from the centre of
the bottom bracket. At present it is usual to arrange the eccentric with the longest
radius on a horizontal line running forward through the centre of the bottom
bracket.
If desired other means, instead of worm gearing, can be used for shifting the
position of the sleeve within the bottom bracket.
P
ר ז'
1040
COMPLETE SPECIFICATION.
Improvements in Crank Driving Mechanism for Velocipedes.
I, JOHN MOUNTGOMERY COLLINS, late of 45, Bartholomew Street, Bridgeton,
Glasgow, now of 121, Swanston Street, Bridgeton, Glasgow, 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:
1
This invention relates to crank driving mechanism for velocipedes and it is a
development of and improvement upon my prior invention No. 18322 dated
6th August 1897.
In order that my said invention may be properly understood I have hereunto
appended an explanatory sheet of drawings, whereon,
Fig. 1 is a side elevation of a bicycle constructed in accordance with my inven-
tion.
Fig. 2 is an enlarged side elevation of the crank driving mechanism of the
bicycle.
Fig. 3 is a transverse vertical section taken on the line -
Fig. 2.
Fig. 4 is a cross section showing the revoluble sleeve and bottom bracket.
Fig. 5 is a side view of the sleeve.
Fig. 6 is an enlarged detail view.
Figs. 7 and 8 are views explanatory of the movements of the sleeve within the
bottom bracket.
Referring to the drawings whereon the same reference numerals wherever
repeated indicate the same parts.
1 is the bottom bracket of the machine. 2 is the hollow crank shaft. 3 is the
solid crank shaft carried within the hollow shaft. 4 is the revoluble sleeve. 5 is
the chain wheel. 6 is the slotted cross bar of the chain wheel. 7 is the driving
11 is the
chain. 8 the driving wheel. 9 is the front wheel. 10 is the frame.
handle bar. 12h are the pedal cranks.
Under this invention the eccentric 12 upon which the chain wheel revolves
is, by preference, made in one with the bottom bracket 1 and it is screwed externally
for the reception of a screwed cup ring 13 and cone ring 14. These rings, as
shown, form a race for the balls 15 in conjunction with the groove 16 made on the
inner periphery of the chain wheel. The slotted cross bar 6, in which the crank
pins 17, 18, work, is made. with lugs 20 which are attached to the chain wheel by
means of screws or bolts 19. In order to lock the cup and cone rings in their
adjusted position on the eccentric the rim of the latter is, at a suitable position such
as 12 Fig. 2, made with a slit or slot for the reception of a wedge pin which

page_text: may be either round or square and which, when driven into place, jams both
rings tightly in position. The rim of the eccentric may be made with an edge or
flange for checking the cup and cone rings.
It will be seen that the mechanism is made in a number of separate parts
which can be easily fitted in place and also easily renewed when damaged or
broken.
A feature of the invention is the provision of improved means whereby the
working centre i.o., the centre of revolution of the hollow and solid crank shafts
or spindles can be shifted, at will, relatively to the centre of the chain driving
wheel. In carrying out this part of my invention I make the bottom bracket 1 of
the velocipede larger than usual and I insert therein the revoluble sleeve 4. This
sleeve is made with a hole 21, extending from side to side, which is eccentric
of the sleeve and serves as a bearing for the crank shaft 2. The sleeve can be
made as a solid cylindrical piece but I prefer to make it with a reduced or cut
away part 22 so as to leave two eccentric bearing flanges 22", 22b. 23 are worm
wheel teeth cut round the periphery of the flange 22" whilst 24 is a circumferential
groove into which the point of a screw 25, inserted in the bottom bracket, cau
enter so as to retain the sleeve in position (within the bottom bracket) and
prevent it moving laterally when the machine is running. 26 is a worm shaft
whose worm teeth 27 mesh with the teeth 23 of the sleeve (see Fig. 4). The wormi
is carried within a hollow extension 28 made on the bottom bracket. 28" is a screw
plug inserted in the extension and provided with a central hole through which
the shaft 26 passes. The upper end of the shaft 26 is carried to the bottom of the
ball head of the bicycle and is provided with a pinion 29 (Fig. 6) whose teeth
mesh with a toothed sector 30 pivotted at 31 to a lug on the ball head bracket 33.
A hand lever 32 is rigidly secured to the sector so that when the hand lever is moved
the sector is caused to turn upon its pivot and rotate the pinion 29 and shaft 26
with the result that the sleeve is also caused to turn within the bottom bracket.
With this arrangement, as will be understood, whenever it is desired to vary
the leverage of the pedal cranks, all that is necessary is to turn the sleeve 4 (which
carries the working spindles or axles 2, 3, with it) so as to vary the distance of the
working centre from the centre of the chain driving wheel. Fig. 7 shows the sleeve
adjusted to the best position for effectively utilizing the maximum leverage whilst
Fig. 8 shows the sleeve turned round so as to give a reduced leverage. The dotted
circle 34 indicates the path of travel of the working centre a during one revolution
of the sleeve 4. is the centre of the bottom bracket and c is the centre of the
chain wheel.
It is to be noted that the eccentric 12 is arranged with its longest radius nearly
directly downwards in a vertical line from the centre of the bottom bracket. At
present it is usual to arrange the eccentric with its longest radius on a horizontal
line running forward through the centre of the bottom bracket.
If desired other means, instead of worm gearing may be used for shifting the
position of the sleeve within the bottom bracket.
The sleeve may be made of aluminium, for lightness, and in this case the hole 21
would preferably be provided with a tubular steel liner.
By shifting the sleeve 4 within the bottom bracket the angle made by the
pedal cranks with one another can be varied. When the sleeve is adjusted so
as to set the pedal cranks to the angle shown at Figs. 2 and 3 dead centres are
avoided and a steady drive is ensured against a head wind or up hill.
If so desired the inner ring or part 5 of the chain wheel may be made separate
and be secured to the toothed portion of the wheel by lugs and bolts or screws.
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 consider novel and desire to claim is:-
1. The construction or general arrangement and combination of parts of the
crank driving mechanism, substantially as herein before described with reference
to the drawings annexed.

page_text: 2. In a velocipede, the combination with the bottom bracket and the driving
cranks of a revoluble sleeve fitted within the bottom bracket and which carries
the driving crank spindles or axles eccentrically within it and means for turning
the sleeve within the bottom bracket, substantially as hereinbefore set forth.
Dated this 5th day of May 1899
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.