Improvements in Rear Driving Gear for Bicycles and Tricycles.
Year: 1894

page_text: Date of Application, 31st Mar., 1894
Complete Specification Left, 31st Dec., 1894-Accepted, 9th Feb., 1895
PROVISIONAL SPECIFICATION.
Improvements in Rear Driving Gear for Bicycles and Tricycles.
I, WILLIAM DEVOLL of Cuba Villa Chester Road, Erdington, in the County
of Warwick, Engineer, do hereby declare the nature of this invention to be as
follows
-
In the Specification of a Patent granted to me on the 9th day of November 1892,
No. 20,183, I described an arrangement of driving gear for the purpose of propelling
bicycles and tricycles, without the use of chain gear which is much objected to, on
account of the frequent stretching of the chain which causes much back-lash, and
loss of
power.
My present invention relates to improvements in the wheels of the driving gear,
and an improvement in the bracket, whereby I obtain a much smoother action of
the wheels in working, and less back-lash, than can be obtained with ordinary spur
gear, having straight teeth.
In the working of screw or spiral gears, a tooth does not strike along its whole
face at once, but comes into gradual contact; thus insuring smoothness and ease in
working.
The smoothness of working and absence of back-lash, is of great importance in
the driving gear of bicycles and tricycles.
For this purpose I arrange a screw or spiral gear within a detachable bracket
made in two parts, and bolted together as shewn in No. 20,183, of 1892 but having
a fillet or lip cast on the inside edges of the bracket, which when screwed together
forms a dust tight cover, and oil trough for the gear wheels.
The pedal crank axle is journalled in the forward portion of the bracket, and a
supplemental crank shaft journalled in the rear portion.
Gear wheels having screw, or spiral teeth are secured on the main and supple-
mental shafts, an idler gear is journalled between the said gear wheels, and meshes
therewith.
In another modification of my said inventior, the idler gear, is journalled at
right angles between the said gear wheels, and meshes therewith, the pivot or
stud on which it is journalled is secured to the bottom of the bracket.
The spirals or teeth are arranged to give a forward motion to the supplemental
shaft in the same direction as the pedal crank shaft, I prefer a proportion of two
revolutions of the supplemental shaft to one of the pedal crank shaft, but other
proportions may be used.
Small driving cranks, are fitted at right angles on the ends of the supplemental
shaft, which extend through the walls of the bracket, and are connected by
coupling rods to cranks on the axle of the rear wheel as described and shewn in
No. 20,183, of 1892.
The shafts revolve in ball bearings fitted to the bracket in the usual manner.
When a forward motion is given to the pedal cranks by the rider, the spiral gear
will cause the suppleinental shaft to revolve in the saine direction, and by means of
the cranks and coupling rods the rear wheel of the bicycle or tricycle will be
propelled forward.
Doted this 30th day of March 1894
WILLIAM DEVOLL,
Per J. J. Raggett,
Agent.

page_text: Improvements in Rear Driving Gear for Bicycles and Tricycles.
I, WILLIAM DEVOLL, of Cuba Villa, Chester Road, Erdington, in the County
of Warwick, 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 :-
This invention relates to the driving or motion-transmitting gear of cycles, and
is a development of former Letters Patent granted to me, and dated the 9th day of
November 1892 No. 20183.
My present invention consists in the employment of tangential or spiral toothed
gearing, instead of plain spur gearing, as in my said former Letters Patent, and
also in ineans of mounting and carrying the said gearing.
Thus, according to my present invention, I employ three coupled-together
toothed wheels having tangential screw or spiral teeth, preferably disposed at an
angle of 62 degrees, and which said wheels are mounted upon adjustable ball
bearings enclosed within a combined gear case and bracket, made in two parts.
Motion from the said gear is communicated to the driving wheel of a machine
either through the medium of coupling or connecting rods, as in my said former
Patent, or through the intervention of an endless chain.
My improvements are applicable to ordinary safety bicycles and to tricycles.
Figure 1 of the accompanying drawings represents, in side elevation, a rear-
driving safety bicycle, provided with motion-transmitting gear means constructed
and arranged according to my present invention.
Figure 2 represents, upon an enlarged scale, a vertical section of the combined
gear case and bracket, with the means of attaching the same to the frame members
of a machine in elevation.
Figure 3 represents a horizontal section of Figure 2, upon the dotted lines.
This view shows, in elevation, the dispositions of the parts, and also shows the
tangential or spiral gear, by the employment of which, smoothness of action and
more power is obtained, without backlash.
Figure 4 represents a modified form of my invention, in which the motion of the
gear is transmitted through the medium of chain wheel gear.
Figure 5 represents the driving gear wheels separately.
The same letters of reference indicate corresponding parts in Figures 1, 2, 3,
and 4.
The transmitting and multiplying gear consists of a driving wheel a, inter-
mediate wheel h, and a driven pinion e, all having tangential or spiral teeth
meshing or intergearing one with another, and being enclosed and working within
a combined dust-proof and oil containing case and bracket d, made in two
parts d', f, bolted together, and supported by and connected to the members c, e¹,
of a cycle framing, by a flange ³, connected, either by holts or otherwise, to a
flange d', carried by the double socket e, of the said frame members e, e¹.
Now the wheel a, is made fast to the axle f, which is provided with pedal
cranks f, at its outer ends, and has necked or collared ball races f³, at its inner
parts, coming adjacent to the wheel, and passing through hollow necks d³, fitted
with adjustable ball bearing cones d', between which and the coned races ³, ball
bearings do, come. The pinion c, has an axis c', ball bearing races c³ adjustable
cones c³, and ball bearings c, fitted within a like hollow neck d³, as before.
The intermediate wheel b, is mounted and loosely runs upon ball bearings
coming between adjustable cones 63, mounted upon a screwed spindle 6, and
races b, in the wheel and with the offside cone secured or keyed, after adjustment,
to the casing by a pin or cottar 6º.

page_text: The pinion c, which is made fast upon its axle c', carries at its ends, driving
crank arms g, set at right angles to each other, and motion from which is
communicated by rods g', whose after ends g³, are connected to like crank arms g³,
made fast to the axle g, of the rear wheel h.
On the wheel c, being driven in the same direction as, and speeded from, the
driving wheel through the pedal crank axle, motion is communicated to the rear
and propelling wheel of the machine.
In Figure 4, in which the driving crank arms of the driven pinion are
substituted by chain gear, i is a chain wheel, fast upon one end of the axle c¹,
and j is a chain, in gear with a like chain wheel as i, made fast to the axle of the
rear wheel.
a is the driving wheel on the crank axle f, intergearing with an
intermediate wheel b, which in turn gears with the driven wheel c, on the axis c¹,
to which the chain wheel i, is keyed. 2 are the cranks.
Figure 6 represents a modified arrangement of chain-driven gear, in which the
driven wheel comes upon the outside and the driving wheel is located between the
driving and driven chain wheel, thus making the gear wheels come under the class
of levers of the second order.
a, b and c are the screw or tangential driving, intermediate and driven gear
wheels, with the teeth preferably arranged at an angle of 62 degrees,
and c¹ are
the axles of the wheels a and e; i is the chain wheel on the axle c¹, the crank
arms on the axle f, and the chain in gear with the chain wheel upon the rear hub
of the cycle.
Instead of three transmitting and speeding wheels, I may employ four.
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 :-
First. In driving or motion-transmitting gear of cycles, employing in conjunction
with the pedal crank axle, three or more spiral or screw toothed motion-
transmitting and speeding wheels, substantially as described and set forth.
Secondly. In the driving gear of cycles, the combination with tangential or
spiral toothed gear wheels, of motion-transmitting crank arms and connecting rods,
or of chain wheels and chain gearing, substantially as described and set forth.
Thirdly. In the driving gear of cycles, the combination with motion-transmitting
and speeding gear wheels, of a segmental and combined gear case and bracket,
substantially as described and set forth.
Fourthly. The improvements in the driving and speeding gear of cycles,
substantially as described and set forth in Figures 1 to 6.
Deted this 90th de
bo 1001
WILLIAM DEVOLL,
By Henry Skerrett,
6, Livery Street, Birmingham, Agent for Applicant.