An Improved Duplex Driving Gear for Bicycles and other Cycles, and for other purposes.
Year: 1898

page_text: "Date of Application, 11th Jan., 1898-Accepted, 16th Apr.,
1898
COMPLETE SPECIFICATION.
An Improved Duplex Driving Gear for Bicycles and other Cycles, and
for other purposes.
I, WILLIAM JAMES THOMPSON, of Warialda Street, West Kogarah, near Sydney,
in the Colony of New South Wales, Civil Engineer, do hereby declare the nature
of my invention for " an improved duplex driving gear for bicycles and other cycles,
and in what manner the same is to be performed to be par-
and for other purposes
"
ticularly described and ascertained in and by the following statement:
This invention refers to an improved duplex driving wheel and connections
specially devised to provide interchangeable high gearing and low gearing for
bicycles though it may equally as well be used on other cycles and for other
purposes.
An improved duplex driving gear constructed according to this invention has
a rim wheel or sprocket having internal teeth gearing with a series of toothed
pinions in gear with a toothed wheel on the axle which toothed pinions thus sup-
port the rim wheel or sprocket in its proper position and when desired revolve
said rim wheel or sprocket. It has a locking plate and a spring locking pin
adapted the plate to lock the central toothed wheel to the revolving or crank disc
and the pin to actuate the plate and release it from the teeth of the central toothed
wheel and to lock said central toothed wheel to the frame of the cycle or stationary
part of other mechanism. It has also connections to the handle part of the cycle
for the purpose of controlling the movement of the spring locking pin.
But in order that this invention may be clearly understood reference will now
be made to the drawings herewith in which Figure 1 is an elevation of a safety,
bicycle having this improved duplex driving gear Figure 2 is a view looking from
the bicycle of the improved duplex driving gear with dust cover removed. Figure 3
is a face view and section of the locking plate in its released position. Figure 4
is a plan portion of the bicycle showing the improved duplex driving gear in
section on the radii a and b of Figure 2. Figure 5 is a partial face view of the
dust cover.
The crank disc B is firmly attached at A1 and A2 to the pedal crank A and it
carries pintles or centre pins B₁ for the toothed pinions C each of which gears into
a central toothed wheel D on ball bearings D₁ and into the internal teeth of the
rim wheel or sprocket E thus holding said rim wheel concentric with the pedal
spindle. A locking plate F has slot guides F1 on pintles 12 on disc B and this
plate has bearing piece or flange F2 key piece F³ and toothed sector F³ and bears
against a spring F adapted to retain said toothed sector F³ in gear with the
central toothed wheel D and the key piece F5 in engagement with way or slot D³
and so cause said wheel D to revolve with the disc B as do the pinions C without
revolving the said pinions C. In this position the motion of the pedal cranks A
is imparted to the rim wheel or sprocket E without multiplication and thus the
low gearing provided. The locking pin G is carried by bands or clips G³
around the hanger bracket or other convenient part and it has a spring G adapted
to press it towards and into the driving gear but the action of said spring pin is
controlled by connections hereinafter described. When the control is released
the spring forces the pin G on to the inside or dust cover H in which there is
alot or opening H¹ through which protrudes the bearing piece or flange F2 of

page_text: locking plate F. The pin G catching on the inside of this piece Fa forces it out-
wardly from the centre and thus moves plate F into the position shown by dotted
lines Figure 2 and by full lines Figure 3. This releases wheel D from the
sector F3 and from the key F5 but as said wheel D revolves it brings under pin G
the key way or socket D³ into which said pin finds its way (see Figure 3) and
thus stops further revolution of said wheel D. The wheel D not revolving the
pinions C carried on disc B as they pass around said wheel D are caused to revolve
and give motion to rim wheel or sprocket E independent of the motion of disc B
and very much faster that it. Thus is provided the high gearing. To change
from the high to the low the pin G is withdrawn (against the impulse of spring G¹)
and thus freeing the wheel 1) to revolve and allowing the plate F by the force
of spring F to again lock it to the disc B.
The operating connections consist of draw piece J¹ bell crank Ja cord or rod or
chain J3 bell crank J cord or rod or chain J5 and a handle lever J the depression
of which handle J will withdraw the pin G so that the low gearing will be the
normal gearing though it might be conversely arranged.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
:-
First. Improved duplex driving gear for bicycles and the like consisting of a
rim wheel or sprocket supported in internal teeth by a series of toothed pinions
carried by a crank dise and in gear with a central toothed wheel adapted to inter-
changeably revolve with said crank disc or to be released therefrom and have no
revolving motion substantially as herein described and explained.
Second In duplex driving gear of the class set forth the combination and
arrangement with a rim wheel or sprocket such as E toothed pinions such as C on
a crank disc such as B and a central toothed wheel such as 1) of a locking plate
such as F travelling with said disc such as B and having toothed sector such as F³
and key such as F adapted to gear in said central toothed wheel such as D and
lock it to said disc such as B and to release said wheel such as D) so that its revolu-
tion can be stopped substantially as herein described and explained and as illus-
trated in the drawings.
Third In duplex driving gear of the class set forth the combination and
arrangement with the other parts and a locking plate such as F having a bearing
piece or flange such as F2 of a spring pin such as G adapted to move said plate
such as F and to lock central toothed wheel such as 1 from revolving substantially
as herein described and explained and as illustrated in the drawings.
Fourth The combination and arrangements of mechanical parts all together
forming an interchangeable duplex driving gear substantially as herein described
and explained and as illustrated in the drawings.
Fifth The combination and arrangement of mechanical parts all together form-
ing a duplex driving gear for bicycles operated from the handle bars substantially
as herein described and explained and as illustrated in the drawings.
Dated this Twenty-sixth day of November One thousand eight hundred and
ninety-seven
Witness:
FRED WALSH,
Fel. Aust. Inst. P.A., Sydney.
WILLIAM JAMES THOMPSON,