Improvements in Change Speed Gear.
Year: 1899

page_text: Date of Application, 29th May, 1899
Complete Specification Left, 27th Feb., 1900-Accepted, 19th May, 1900
Date of Application, 29th May, 1899
Complete Specification Left, 27th Feb., 1900-Accepted, 19th May, 1900
Improvements in Change Speed Gear.
I, RALPH LUCAS, of Beth Combe, Charlton Road, Blackheath, in the County
of Kent, Engineer, do hereby declare the nature of this invention to be as
follows:-
According to this invention an endless belt of constant length works on two
expanding belt pulleys, which are actuated by springs, in such a manner that
they always have a tendency to expand to their largest diameter, but are held
in check by the tension of the driving belt, so that when the diameter of one
pulley is reduced the other pulley expands as far as the belt permits; so altering
the ratio of their speeds of rotation, while keeping the belt at a constant tension.
I form the periphery of each expanding pulley of a ring of steel lattice work
jointed together lazy tongs fashion.
This ring surrounds a number of pins which are parallel to the shaft and
whose ends work in radial slots in a pair of discs fixed to the shaft and are
pivotted to the ends of links whose other ends are pivotted to
discs free to rotate on the shaft. By turning the latter dises rela-
tively to each other the distance of the pins from the shaft is varied. These discs
are actuated by springs which tend to so turn them as to keep the pius at their
maximum distance.
I preferably use a jockey roller or rollers, so that by pressing against one of
the pulleys it overcomes the springs, causing that pulley to diminish in diameter,
the other pulley expanding by the action of its springs as far as the belt allows.
The jockey roller may be operated by a lever so that pressing the lever in one
direction gradually increases the speed while by moving the lever in the other
direction the speed is gradually reduced to its minimum and finally by contract-
ing the driving pulley yet further after the driven pulley has reached its maxi-
mum limit the belt is slackened, thus finally bringing the driven shaft to rest.
The driving pulley may also be expanded or contracted by screw or other
gear, while the driven pulley is actuated by springs as already described.
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Improvements in Change Speed Gear.
I, RALPH LUCAS, of Beth Combe, Charlton Road, Blackheath, in the County
of Kent, Engineer, do hereby declare the nature of this invention and in what
Price 8d.1

page_text: manner the same is to be performed to be particularly described and ascertained
in and by the following statement:―
According to this invention an endless belt (or it may be two belts running
on pulleys on an intermediate shaft) of constant length works (or work) on two
expanding belt pulleys which are actuated by springs in such a manner that they
always have a tendency to expand to their largest diameter but are held in check
by the tension of the driving belt (or belts) so that when the diameter of one
pulley is reduced the other pulley expands as far as the belt (or belts) permits
(or permit) so altering the ratio of their speeds of rotation while keeping the belt
(or belts) at a constant tension.
I form the periphery of each expanding pulley of a ring of steel lattice work
jointed together lazy tongs fashion.
Figure 1 is an underside view of the arrangement when an intermediate shaft
is employed. Figures 2, 3 and 4 are side elevations showing the positions of the
parts when driving at the fastest, slowest and middle speeds respectively.
Figure 5 is a side elevation, and Figure 6 a plan of one of the expanding
pulleys.
Figure 7 is a section on the line A-B Figure 6, and Figure 8 is a similar
view but with the pulley contracted instead of expanded.
Figure 9 shows a modification of Figures 1 to 4 only one belt being employed.
In Figures 1 to 4 a is the driving shaft and the driven shaft and ce are
expanding pulleys fixed on them. d is an intermediate shaft having two pul-
leys e fixed to it. f are belts of constant length working around the two
pairs of pulleys c and e. The shaft is moved between the shafts a and b by
any convenient means. In Figure 2 the pulley c on the shaft a has expanded to
its largest size whilst the pulley c on the shaft has been compressed to its
smallest size so that the shaft bis being driven at its maximum speed whilst
in Figure 3 the conditions are exactly reversed. In Figure 4 the shaft d is
midway between the shafts a and b and the pulleys c on the two latter shafts are
therefore of equal size.
Figures 5 to 8 show the construction of the pulleys c. g are a number of
bars pivotted together at their middles and ends lazy-tongs fashion and some of
them are also pivotted at their middles to six cross bars working in radial
slots in two discs ; which form the sides of the pulley. The cross bars are
connected by links to plates 1. m are pins fixed to the plates 7 and projecting
through circular slots n in the disc o are springs each having one end fixed
to one of the pins m and its other end to a pin fixed to the disc j. The springs
therefore always tend to expand the pulley, that is to say, bring the parts from
the position shown in Figure 8 to that shown in Figures 5, 6 and 7.
P
In Figure 9 only a single belt f is employed the pulley e on the shaft a
being contracted by pressing a jockey pulley 7 against it.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:--
1. A pulley having its periphery formed of a series of bars jointed together at
their middles and ends lazy-tongs fashion and provided with springs constantly
tending to expand it.
2. In an expanding pulley the combination of two side discs, transverse bars
working in radial slots in the discs, a series of bars jointed together at their
middles and ends and some of them also pivotted at their middles to the trans-
verse bars and means for moving the transverse bars simultaneously in a radial
direction.
3. In an expanding pulley the combination of two side discs, transverse bars
working in radial slots in the discs, a series of bars jointed together at their
middles and ends and some of them also pivotted at their middles to the transverse

page_text: bars, a plate free to turn about the axis of the pulley, links connecting the plate
to the radial bars and springs tending to turn the plate.
4. The combination of two pulleys which always tend to expand, belt-gearing
connecting the pulleys, and means for causing the belt gearing to press inward
the periphery of one of the pulleys.
5. The combination of two pulleys which always tend to expand, two pulleys
of constant diameter on a common shaft, two bolts each passing partly around
one of the expanding pulleys and one of the non-expanding pulleys and means
for moving the non-expanding pulleys relatively to the expanding pulleys.
6. Change speed gear substantially as described and illustrated by the drawings.
Dated this 20th day of February 1900.
RALPH LUCAS.