Improvements in Variable Speed Gearing for Velocipedes.
Year: 1889

page_text: Date of Application, 18th Apr., 1889
Complete Specification Left, 20th Jan., 1890-Accepted, 12th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in Variable Speed Gearing for Velocipedes.
I, CHARLES WICKENS PLOWMAN, of 3 Pembroke Villas, Richmond Green, of no
occupation or calling, do hereby declare the nature of this invention to be as follows:-
I propose to substitute for the usual driving chain a shaft, A A¹ in the accompanying
drawing No. 1, carrying at each end a bevelled pinion B B'; & in the case of an
existing machine I affix to the faces of the two chain wheels respectively, at the
periphery, a toothed & bevelled ring CC, thus converting the chain wheels into bevel
wheels, which
gear with &are perpendicular to the bevel pinions of shaft, so that the
rotation of the fore wheel will rotate the hind wheel at the same rate of multiplication
(or "gearing of") as if the connexion were by chain as heretofore; & in the case of
a new machine I substitute, for the ordinary chain wheels, bevel wheels of the same
size.
And to vary the gearing (e.g. substitute power for speed) at will, I cut the shaft
transversely into two parts, A A¹ so that whilst each part is radial (with its bevel
pinion) from the centre of one of the bevel wheels, they lie parallel to but at a
certain vertical distance apart from each other; & I connect them together by two
pairs of small spur wheels, one pair, D D', being of equal diameters & the other
pair, E E, of unequal diameters. The lower wheel of each pair is a fixture to the
lower shaft, & the upper wheel of each pair runs loose upon the upper shaft; but
by a clutch arrangement, F, either can be made a fixture to the shaft at will by
moving a lever G. Thus when wheel D¹ is fixed, the shafts are connected through
the pair D D', the wheel E¹ running loose; & as this pair are of equal diameters,
the multiplication arising from the difference of size of the two chain wheels takes
effect; but when wheel E is fixed & D' loose, the connexion between the shafts
is by the pair E E', & as this pair are of different diameters in the same ratio, but
inversely, as that between the two chain wheels, the latter run at the same speed
& the multiplication is done away with, & the machine is "geared level." Other
variations of gearing (e.g. " gearing down") may be effected by adding a third pair
of spur wheels of diameters differing in a suitable ratio.
As an alternative arrangement of parts in this invention, I fit the face of fore chain
wheel with two or more annular bevels, A. B. in drawing No. 2, of differing
diameters, gearing respectively with two or more bevelled pinions, C. D), running
loose on fore end of shaft E, but capable of being fixed for use by clutches as above
at will, & all of the same size, so that the shaft will rotate at different speeds according
to which of the pinions is in use whilst the other, or others, run loose on their
respective bevels. To make both chain wheels run in the same direction, the rotation
of shaft (which is not cut in two as above) is communicated to rear chain wheel
through a pair of pinions, F. G, of equal diameters, one of them being fixed to shaft
& the other to a short shaft, H, radial to rear chain wheel, & having at its end a
pinion, I, like those on fore end of principal shaft but fixed to it & gearing with
bevelled periphery, J, of rear chain wheel. The second shaft, H, & its pinions
might be dispensed with by making the principal shaft, E, to gear by a screw
pinion with the rear half of hind chain wheel, in the case of machines where the
face of the wheel is free from obstruction so as to admit of shaft crossing immediately
above or below its axle instead of being radial.
T
1711 1
と A
*1000

page_text: •
COMPLETE SPECIFICATION.
Improvements in Variable Speed Gearing for Velocipedes.
1 CHARLES WICKENS PLOWMAN, of 3 Pembroke Villas, Richmond Green (Surrey)
of no calling, 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 :-
I use the method of connexion by shaft & gear-wheels instead of that by chain
& cog-wheels-i.e., I substitute bevel crown wheels (toothed or frictional) for the
more usual chain-wheels of a velocipede & I connect them together by a shaft carrying
at its ends bevel pinions (toothed or frictional) which gear with such crown wheels,
the diameters of which latter differ in the saine ratio as that usually adopted in the
case of such chain-wheels; & for the purpose of "variable speed" I divide the shaft
into two sections (A A¹ in drawing No. 1 left with the provisional specification) & I
connect the two sections together by two pairs of spur-wheels one pair D D' being of
equal diameters, & the other pair E E' of unequal diameters. The lower wheel of
each pair is a fixture to the lower shaft, & the upper wheel of each pair runs loose on
or is fixed to the upper shaft at will by any suitable clutch arrangement, such-e.g.-
as a sliding shaft-key. Thus when the pair D D', which are of the same diameter,
transmit the motion the machine is "geared up," but when E E' are used it is (in
the particular instance shown in the drawing) "geared level," as this pair differ in
diameter in the same ratio (but inversely) as the two crown-wheels C. C. As an
alternative & probably preferable arrangement of parts in this invention, I make one
of the crown-wheels (either of them) a double crown-wheel, annularly or concentrically,
these annular circles of teeth gearing respectively with two bevel pinions which run
loose on or are fixed to the shaft (which is now in one piece) at will by a clutch, so
that the speed will vary according to which of such circles is in gear with the shaft
through the fixing of a pinion, the other pinion running loose. "In order that the
driving-wheels of the velocipede may revolve in the same direction as the crank, the
shaft in this arrangement gears with the single crown wheel through its pinion by
making the teeth of such wheel on its reverse face, the shaft then running from the
face of one wheel to the back of the other.
Having now particularly described & ascertained the nature of my said inven-
tion, & in what manner the same is to be performed, I declare that what I
claim is―
Varying the speed of the driving-wheel or wheels of a velocipede in relation to
that of the crank-axle of the same by applying the principle of the "fast or loose
wheel" in the way or ways above set forth.
Dated this 18th day of January 1890.
C. W. PLOWMAN.