Improvements in or connected with Driving Gear for Velocipedes.
Year: 1894

page_text: Improvements in or connected with Driving Gear for Velocipedes.
JOHN DICKSON DERRY Civil Engineer 22 Great Winchester Street London E.C.
I do hereby declare the nature of this invention to be as follows:-
Charged spring, retainer or check, for power maintaining devices, applicable to
velocipedes.
This invention retains or checks the force accumulated in springs that have been
charged by power applied to a crank and compels such force to be expended in
propelling the machine.
Without such retainer or check, at least one half of the force exerted in charging
er loading the spring or springs is lost by reaction and if power applied to the
crank or cranks be withdrawn before the propelling power can again be applied
the force accumulated in the spring or springs is lost.
To prevent such loss I formi a ratchet on the driving arm or wheel that creates
or establishes such force and fix a catch or pall to a portion of the frame of the
vehicle (carrying the crank shaft and its connected gear) so as to engage the teeth
of the ratchet and prevent the driving arm or wheel turning back against the
power; consequently the force will strain or pull the driving chain independently
of the power.
To illustrate the action of the ratchet and catch I have taken the Specification
and plan of Guild's Patent No. 18347 of 1892 which invention is described as "An
22 Guild's
arrangement of mechanism for assisting cranks over their dead centres.'
invention depends entirely on the motive power being continuously applied,
therefore only half the force of the compressed spring is transmitted to the
driving chain, because action and reaction must be equal and if the power be
withdrawn before it can again be applied to the second crank, the force in the
compressed spring is entirely lost or has no effect in propelling the machine.
6.
In order that my invention may be made clear I have applied the same to
Guild's plan. Sheet Fig. 3 is an elevation and Fig. 4 a cross section. The
various additional parts are lettered. j. j. are segmental ratchets to be formed in
one with the "sleeve a" and the " radially projecting arms c c." It must be
clearly understood that in this case the ratchets are not attached to the chain
wheel "e" which is capable of an independent limited circular movement upon the
sleeve "a" so that the segmental ratchets can be moved in advance of the chain
wheel (when the spring is compressed). A catch or pall k is connected with the
frame of the vehicle in such a manner that it can engage the teeth or cogs of the
ratchets, a small spring pressing it down or home.
I make four cogs or teeth so that the compression can be taken up or retained in
part or wholly. The connection with the frame of the vehicle or machine is
effected by means of the bracket n, rigidly secured to the frame. 0. o. is a stop to
limit the radial distance of the catch & prevent the noise it might otherwise make
in meeting the rear slope of the tooth.
With other forms of maintaining power springs it may be necessary to make the
ratchet a complete circle which would enable the compression of a volute or other
form of spring to be used necessitating one or more complete revolutions of the
ratchet before the limit of the springs elasticity is obtained. A rod p is attached.

page_text: to the catch to provide a ready means of raising it and throwing it out of gear,
such as, when running down hill or desiring to run the machine backwards.
The catch being engaged, thus preventing the backward movement of the
velocipede facilitates supporting the machine when at.rest.
The lines gg & r r approximately measure the arcs in traversing which little or
no power can be transmitted by the pedals to propel the machine & are termed the
"dead points." b. b. indicate the seats or positions of the cranks.
65
66
g" "g "show that I propose to make the "stop "g" moveable instead of being
"formed in one with the chain wheel." The advantage of being moveable is that
the helical spring can be compressed to any degree and fixed there, thus regulating
the strength or resistance of the spring.
The ratchet to retain or check a charged spring may require to form a part of
the pedal chain wheel (the catch always being on the frame) when the spring force
is differently applied such as through the medium of the chain.
Dated this 13th day of September 1894.
J. D. DERRY,
22 Great Winchester Street, London, E.C.
Improvements in or connected with Driving Gear for Velocipedes.
I JOHN DICKSON DERRY of 22 Great Winchester Street in the City of
London, a Member of the Institute of Civil Engineers Consulting 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::-
The invention relates to improvements in or connected with driving gear for
velocipedes, and has for its object to combine with driving gear of the character
shown and described in the Specification of Letters Patent granted to James
Findlay Guild, dated the 13th day of October 1892 No. 18347, means whereby the
power stored by the compression of the springs will be retained and given out in
the proper direction notwithstanding that the feet be removed from the pedals.
Driving gear of the character referred to comprises in the case of a rear driven
safety bicycle a chain wheel which through a chain gives motion to the driving
wheel, and within this chain wheel is an annular chamber in which are placed two
helical springs which act against abutments or projections upon the interior of the
annular chamber, whilst the crank shaft has fixed therewith two arms or projections
which act upon the opposite ends of the helical springs, and in the ordinary working
of the machine more or less compress the springs between the same and the
abutments and the power is thus transmitted from the crank shaft through the
springs to the chain wheel and thus to the driving wheel.
The effect of this device is to more evenly distribute the power exerted by the
rider in driving the machine and also to minimise shocks occasioned by obstructions
upon the road, but it possesses the disadvantage that unless the pressure upon the
pedals be constantly maintained the springs will recoil and much of the benefit
derived from the interposed spring will be lost.
Now according to the present invention the power stored by the compression of
the springs is retained and the springs are compelled to give out such power in the
direction required to propel the machine and thus the rider may even momentarily
remove his feet from the pedals and the springs will still continue to propel the
vehicle.
In carrying the invention into effect the wheel or box enclosing the springs is
formed in two parts, one part consisting of a-chain wheel-which-is-mounted loosely
upon a boss of the other part, and such.other part which carries the radial arms or

page_text: And in order that the said invention may be more clearly understood and readily
carried into effect, I will proceed aided by the accompanying drawings more fully
to describe the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation representing a portion of a velocipede having the
present invention applied thereto.
Figure 2 is a sectional elevation thereof taken at right angles to Figure 1.
Figure 3 is a similar view to Figure 1, partly in section but representing a slight
modification.
In the several figures in which like parts are indicated by similar letters of
reference, Figure 3 is drawn to a reduced scale with respect to Figures 1 and 2.
Referring to Figures 1 and 2, a represents the frame of a velocipede, a' represents
the axle box or bearing for the crank axle which is fixed with the frame a in the
usual manner, whilst b represents the crank axle and 6' the cranks, and cd represent
the two parts of the wheel or box enclosing the springs hereinafter more fully
referred to.
The part c of the wheel or box is mounted loosely so as to freely revolve upon
a boss d² of the other part d, and the two parts c d are grooved so that together
they form an annular chamber in which the two helical springs e are contained,
whilst c represents the abutments or projections carried by that part c of the
wheel or box and against which the helical springs e act and d* represents the
two arms or projections which are fixed through the boss and feather d³ with
the crank shaft & and act in the ordinary working of the machine to more or less.
compress the helical springs e against the abutments c*.
C
The periphery of the part c is formed with teeth or projections c² constituting
a chain wheel which by means of a second chain wheel and chain (not shown) is
geared with the driving wheel of the machine as is well understood.
The other part d is by means of the boss and a key or feather d³ fixed with
the crank shaft b and the part d around its periphery is provided with a circle of
ratchet teeth d which are engaged by a pawl f pivotally mounted at 2 upon
a fitting clamped to the two parts a of the frame of the machine, and this pawl fl
is held up to its work by a spring f³ and thus any back action of the ratchet
portion of the box is prevented so that any power stored by the compression of
the springs e will be retained and ultimately given out in the required direction.
In the example given at Figure 3, in lieu of the ratchet wheel d¹ and pawl f¹
herein before shown and described, a friction clutch is employed consisting of a cam
wheel d' fixed with that part d of the wheel or box, and several rollers f¹ which in
the event of any back action of the helical springs e are jammed between the cam
wheel d¹ and a cylinder f fixed with the frame a of the machine by any suitable
means.
This class of friction clutch which is well known as the "Cheylesniore" is
merely given as an example of a retaining device other than the ratchet wheel
aud pawl which may be employed in connection with the present invention, but it
will be evident that there are many other forms of retaining devices which will
answer the purpose equally well.
I am aware that it has before been proposed to employ a ratchet wheel or

page_text: retaining device in combination with a volute spring interposed between the crank
of a velocipede and the driving wheel, but such a device does not possess the same
advantages as when employed in combination with helical springs arranged in a
circular chamber as hereinbefore described, inasmuch as in a volute spring of
sufficient flexibility to allow of its being more or less compressed by the pedal
action there would not be sufficient resistance offered thereby in the event of the
rider applying extra force to the pedals, whereas by the employment of helical
springs in the manner herein before shown and described in the event of the rider
pedalling with sufficient force, the helical springs would be wholly compressed and
would simply form buffers between the power and the work.
I have herein before shown and described my invention as applied more especially
to a rear driven safety bicycle, but it will be understood that it is equally applicable
to velocipedes in which the front wheel is the driving wheel and is driven direct or
through the medium of a chain from the crank shaft, and in this case the loose part
of the spring box would form the hub of the driving wheel.
I would also have it understood that my ratchet or retaining device may be
placed in any convenient position and modified according to the construction of
machine to which it is applied.
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. A driving gear for velocipedes comprising a spring box formed in two parts,
one fixed with the crank axle and the other loose thereon, an annular chamber
in the spring box to receive helical springs, helical springs located within the
chamber, abutments upon the loose part for the springs to act against arms or
projections upon the fixed part to compress the springs against the abutments and
a ratchet or other retaining device for holding the springs in compression sub-
stantially as herein shown and described and for the purpose stated.
2. A driving gear for velocipedes comprising a spring box mounted loosely upon
a shaft and formed with an annular chamber to receive helical springs, helical
springs located within the chamber, a chain wheel and chain or other means for
communicating motion from the spring box to the driving wheel and arms or offsets
traversing the spring chamber for compressing the springs, such arms being fixed
upon a directly or indirectly crank driven shaft, and a ratchet or other retaining
device for holding the springs in compression substantially as herein shown and
described and for the purpose stated.
3. A driving gear for velocipedes comprising a spring box formed in two parts,
one mounted loosely with relation to the crank axle, and the other fixed therewith,
a chain wheel upon the periphery of the loose part geared by means of a chain and
chain wheel with the driving wheel of the velocipede an annular chamber formed
within the spring box, helical springs located within the chamber, abutments fixed
with the loose part for the springs, arms or projections from the fixed part entering
the chamber and adapted to compress the springs against the abutinents and a
ratchet or other retaining device for holding the crank driven or fixed part against
back action substantially as herein shown and described and for the purpose stated.
Dated this 9th day of September 1895.
WHITE & WOODINGTON,
27 Southampton Buildings, London, Agents.