Improvements in the Construction of Differential Speed- or Power-gears.
Year: 1897

page_text: Date of Application, 31st Mar., 1897
Complete Specification Loft 24th Dec. 1807 Accented 5th Feb
1808
Date of Application, 31st Mar., 1897
Complete Specification Left 24th Dec 1807 Accented 5th Feb
1808
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Differential Speed- or
Power-gears.
I, HERBERT ALFRED LUCAS BARRY, of 15, Great George Street, in the City of
Westminster, Engineer, do hereby declare the nature of this invention to he
as follows:
This invention relates to the application of differential gearing to cycles, auto-
cars and other mechanically propelled vehicles, with a view to enabling the
operator to alter the speed or the power imparted to the shaft or wheel driven,
without any alteration taking place in either the speed or the power derived from
the motor or driving shaft.
A differential gear constructed according to my invention comprises two con-
centric toothed wheels of different pitch or diameter, one of which is keyed to
the shaft, the other running loose thereon. Between and concentric with the said
wheels is arranged a disc wherein is or are mounted one or more pairs of pinions
which engage with the toothed wheels; the pinions being so connected that they
must revolve in unison.
The disc carrying the pinions is free to rotate about the shaft, but its periphery
is furnished with a band or brake capable of being tightened, so that the motion
of the disc may be arrested at will.
actuates
Under ordinary conditions, the brake band being released, the shaft
in revolving carries with it the toothed wheel which is fast thereon.
This wheel, meshing with one of the intermediate pinions,
the companion intermediate pinion and thus the toothed wheel which is locse
upon the shaft; the fast and the loose wheels thus revolving in unison, owing
to the intermediate pinions acting as a "lock." Where, however, the brake band
is tightened and the disc carrying the intermediate pinions is held stationary, the
apparatus becomes operative as a differental speed-gear; the toothed wheel which
is loose upon the shaft, and which may be either the driving or the driven wheel,
being rotated at a speed which is different from that pertaining to the wheel
which is keyed upon the shaft.
D
01
1007
:

page_text: - Improvements in the Construction of Differential Speed- or
Power-gears.
I, HERBERT ALFRED LUCAS BARRY, of 15, Great George Street, in the City of
Westminster, 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 application of differential gearing to cycles, auto-
cars and other mechanically propelled vehicles, with a view to enabling the
operator to alter the speed or the power imparted to the shaft or wheel driven,
without any alteration taking place in either the speed or the power derived from
the motor or driving shaft.
A differential gear constructed according to my invention is illustrated in side
elevation and transverse section respectively in Figs. 1 and 2 of the accompanying
drawings, and comprises two concentric toothed wheels A, B of different diameters,
one of which, A, is keyed to the shaft C, the other, B, running loose thereon.
Between and concentric with the said wheels is arranged a disc 1) whereon is or
are mounted one or more pairs of pinions A', B' which respectively engage with
the toothed wheels A and B; each pair of pinions being secured upon a spindle E
common to both so that they revolve in unison.
The disc D together with the pinions is free to rotate about the shaft C, but is
embraced by a band or brake-strap F capable of being tightened about its
periphery, so that the movement of the disc may be arrested at will. With a
view to diminishing friction in the gear, the parts in rubbing contact may be
fitted as ball bearings.
Under ordinary conditions of working, the brake band F being slack, the
shaft C, in revolving, carries with it the toothed wheel A which is fast thereon.
This wheel, meshing with the intermediate pinion or pinions A¹, actuates the
companion intermediate pinion or pinons B₁ and thus the toothed wheel B which
is loose upon the shaft C; the wheels A and B thus revolving in unison, owing
to the intermediate pinions A' B₁ acting as a "lock." When, however, the brake
band F is tightened and the disc D is held stationary, the mechanism becomes
operative as a differential speed-gear; the toothed wheel B which is loose upon
the shaft, and which may be either the driving or the driven wheel, being rotated
(through the intervention of the pinions A¹ B₁) at a speed which is different from
that pertaining to the toothed wheel A. The toothed wheel B, in the present
design, is connected by the screws bb with the chain-wheel B2.
In Figs. 3 and 4, I have shown, by way of example, a method of operating my
differential speed-gear when applied to an ordinary chain-driven safety-bicycle.
Fig. 3 is an elevation and Fig. 4 a view from the rear of so much of the machine
as is necessary for the purpose of illustration; the details of the gear being
omitted for the sake of clearness. One end of the brake-strap F is permanently
attached to an arm or bracket G which is secured by means of a split collar G¹ to
the frame H. The other end of the strap F is attached to a rod I which passes
through the arm G and which is connected at its upper extremity to a two-armed
lever K; the lever being pivoted to a bracket L carried by the top bar or tube H¹
of the frame. The lever K is provided with a projection k, which passes into a
recess in the arm of the bracket L and serves as a stop when the lever is
deflected as shown in the drawing; the band I being then in tension. When,
however, the lever K is moved through the arc ¹, the rod I is caused to descend

page_text: with the result that the band F is released. A spring i may be used for facilitating
the downward movement of the rod and thereby the release of the band.
Although I have illustrated my improved differential gear as applied to a
safety-bicycle, it may, with equal facility be applied to auto-cars and similar
mechanically driven vehicles. By combining two or more sets of such gearing,
the speed or the power communicated to the driven shaft and to the road driving
wheel or wheels may be varied without altering the power of the motor or the
speed of the shaft whence the power transmitted through the gear is derived.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I claim: —
1. The improved differential speed- or power-gear constructed or operating
substantially as herein described and comprising a toothed wheel fast on the
driving shaft, a toothed wheel running loose thereon, a brake-controlled disc and
one or more pairs of pinions which respectively mesh with the central toothed
wheels.
2. In a bicycle, the combination, with a chain-wheel B2, of toothed wheels A, B,
a brake-controlled disc 1) and pinions A¹, B¹, arranged or operating substantially
as and for the purpose set forth
Dated this 21st day of December 1897.
For the Applicant,
G. G. M. HARDINGHAM,
Chartered Patent Agent, 191, Fleet Street, London, E.C.