Year: 1899

page_text: Date of Application, 19th Jan., 1899
Complete Specification Left. 19th Oct., 1899-Accepted, 25th Nov., 1899
I, WILLIAM FRANCIS HACKMAN, of Elthorne, The Greenway, Uxbridge, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this inven-
tion to be as follows:-
My invention relates to an improved chainless driving gear for cycles.
The gear is of that type in which motion is transmitted from cranks (on a counter-
shaft geared with the pedal crank axle) to the driving wheel through the medium
of coupling rods. In this improved gear the coupling rods are housed within the
backstays although they drive the wheel by its hub.
Ball
The pedal crank axle is geared by an internal toothed wheel with a pinion on a
cranked countershaft mounted in ball, bearings in a bracket in rear of and con-
nected with the ordinary bottom bracket, the cranks of this shaft being at 90°
and being coupled by connecting rods and eccentric straps with eccentrics in
of the
hub.
driving wheel
driving connection with the ends
bearings are provided in the connecting rod heads between the eccentric
the eccentric discs, the bosses of the
straps and the peripheries of
eccentrics being mounted to revolve on ball bearings about the spindle of the
driving wheel and being in interlocking or clutch-like connection with the
ends of the driving wheel hub. The coupling rods pass one through each of the
backstays which are of flattened oval tubular section so as to afford space within
them for the parallel movement of the coupling rods.
1000
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
I, WILLIAM FRANCIS HACKMAN, of Elthorne, The Greenway, Uxbridge, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this inven-
tion 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 an improved chainless driving gear for cycles.
The gear is of that type in which motion is transmitted from a countershaft
geared with the pedal crank axle, to the driving wheel through the medium of
073

page_text: coupling rods, which are housed within the stays or tubular members of the lower
back fork, the said wheel being however driven by its hub.
The combination of mechanism which constitutes the invention is illustrated
in the accompanying drawings forming part of this specification wherein Figure 1
is a side elevation of the gear, part of the frame being in section. Figure 2 is a
sectional plan view of the gear. Figure 3 is a cross section shewing the coupling
rods in the stays of the frame. Figure 4 is a section shewing a form of adjust-
able ball bearing for the crank ends of the coupling rods. The same letters of
reference indicate the same parts in all the figures.
The pedal crank axle A has fast upon it an internal toothed wheel B by which
the axle is geared with a pinion on a cranked countershaft D the cranks dd
of this shaft being at 90° to each other and being coupled by connecting rods E E
and eccentric straps F F with eccentrics GG formed or fast on the hub H of
the driving wheel. The countershaft D is mounted in ball bearings I J in a
bracket K in rear of, and connected to, the ordinary bottom bracket L in which
the pedal crank axle is mounted and to the stays or members M of the lower back
fork. The one crank d is preferably an outside or single arm crank on the end
of the shaft D and the other crank d' a double arm crank at an intermediate
point in the length of the shaft the one ball bearing I being contained within the
middle portion of the bracket K adjacent to the crank d and the other ball bear-
ing J being situated at the outer face of the said bracket so as to support the
end of the shaft D beyond the return arm of the crank d¹ on which end the
pinion C is mounted as shewn. The coupling rods EE are preferably tubular
and have ends e attached for connection with the crank pins. These ends e are
split diametrically to enable-adjustment for wear and contain ball bearings, the
ball races being preferably formed by a V-grooved shoulder d2 about the crank
pin and by a pair of oppositely coned liner rings e¹ contained in a V-groove e
within the split end e of the coupling rod, the two liner rings e¹ being caused to
close in towards each other when the split end e is tightened up to take up wear.
The eccentrics G G are formed or fixed on the, opposite ends of the hub H and
have each a peripheral V-groove g to receive balls confined between such V-groove
and an oppositely directed V-groove formed by cups screwing into the eccentric
strap F. By the use of eccentrics, as distinguished from cranks, I am enabled to
drive the wheel by its hub in the same way as when chain driving gear is used,
that is to say the hub H is mounted to rotate upon the usual cup and cone ball
bearings about a dead spindle N secured by nuts n in the rear ends of the stays
or members M of the lower back fork. The coupling rods and the cranks and
eccentrics which they couple together are at the two opposite sides of the machine
each coupling rod being in the central plane of one or the stays M.
These stays
or members M are tubular in order that the coupling rods may pass through them,
there being one coupling rod in each stay and the stays are of flattened oval
section the major axis of the oval being in the vertical direction so as to afford
space within them for the parallel movement of the coupling rods each in its own
vertical plane.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is;-
1. A bicycle driving gear consisting in the combination with a cranked counter-
shaft driven from the pedal crank shaft through the medium of an internal gear
wheel on the latter and a pinion on the former, of coupling rods, connected at
their front ends through ball bearings with said cranks and at their rear ends to
straps encircling, with interposed ball bearings, eccentrics fast on the opposite
ends of the hub of the driving wheel substantially as specified.
2. The combination with bicycle driving gear consisting of a cranked counter-
shaft driven from the pedal crank shaft through an internal gear wheel and pinion,
and whose cranks are coupled by rods with the straps of eccentrics fast on the
:

page_text: driving wheel hub as herein described, of tubular stays or members of the lower
back fork of flattened oval cross section so as to give passage to the coupling rode
and permit of their motion in vertical planes within said stays substantially as
specified.
Dated this 19th day of October 1899.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.