An Improved Varying Speed Motion.
Year: 1893

page_text: Date of Application, 26th Jan., 1893
Complete Specification Left, 25th Nov., 1893-Accepted, 13th Jan., 1894
PROVISIONAL SPECIFICATION.
An Improved Varying Speed Motion.
We CHARLES JOHN BOYCE of 8 Philpot Lane in the County of London
Merchant, and WILLIAM MARCH of 69 Adelaide Road, South Hampstead in the
County of London, Mechanical Engineer do hereby declare the nature of this
invention to be as follows:-
Our improved varying speed motion consists of two shafts placed parallel with
each other and free to revolve in suitable bearings at or near to their extremities.
Each shaft carries two bosses of a pulley, & has, jointed to it, an equal number
of spokes, the outer extremities of which are pivoted to a segment of the rim of
the pulley.
Each spoke is opposite to the corresponding spoke which springs from the
opposite boss & both of these spokes are pivoted to the same rim.
The bosses are kept from revolving on the shaft by means of a feather on each
shaft & are sufficiently long to be common to both bosses.
It follows that when the two bosses which are on the same shaft are made to
approach each other the outer ends of the spokes rise, & each pair forms a more
acute angle in respect to each other which action causes the rim segment to which
they are pivoted to recede from the shaft & thus expand the pulley.
Hence it follows that the larger the pulley the farther apart are the rim
segments; also that when the pulley is at its smallest diameter the ends of the
segments butt against each other.
Double fork arrangements, embracing the bosses, act conjointly, but in opposite
directions upon both pairs of bosses in such a manner that the two bosses upon
one shaft approach each other and expand the pulley, while the two bosses upon
the other shaft simultaneously recede from each other and contract the pulley.
By this means varying speed motion of the driven shaft is ensured, com-
munication from one to the other being obtained through the medium of a
belt.
In order to cause each spoke to rise equally with the opposite one, the inner
edges of their outer ends, which are pivoted to the rim segments, are toothed, and
gear into each other similar to spur wheels.
Dated this 26th day of January 1893.
CHARLES JOHN BOYCE.
WILLIAM MARCH.
An Improved Varying Speed Motion.
We CHARLES JOHN BOYCE of 8 Philpot Lane in the County of London Mill
Furnisher, and WILLIAM MARCH of 69 Adelaide Road, South Hampstead, in
the County of London, Mechanical 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 :-
Our improved varying speed motion consists of two horizontal shafts a shown in
Figures 1 & 2 in the accompanying drawing. These shafts are placed parallel
with each other and are free to revolve in suitable bearings at or near to their
extremities. Each shaft carries two bosses b of a pulley, & has jointed to it an
PRI

page_text: equal number of spokes c, the outer extremities of which are pivoted to segments d
of the rim of the pulley. Each spoke is opposite to a corresponding spoke
which springs from the opposite boss, & both of these spokes are pivoted to the
same segment, & are likewise geared together by teeth as shown dotted in
Fig. 2.
The bosses are kept from revolving on the shaft by means of a feather
on the latter. When the two bosses which are on the same shaft are made to
approach each other each pair of spokes forms a more acute angle in respect to
each other & causes the segment to which they are pivoted to recede from the
shaft and thus expand the pulley.
Hence it follows that the larger the pulley the farther apart are the segments;
also that when the pulley is at its smallest diameter the ends of the segments butt
against each other.
Variation in the diameter of the pullies is obtained by two double forked bars f
in Figure 2, which work upon fixed centres f¹ & are operated by a lever handle
in conjunction with cranks i & connecting rod j in such manner that the two bosses
upon one shaft approach each other and expand one pulley, while the two bosses
upon the other shaft simultaneously recede from each other & contract the other
pulley. By this means varying speed motion of the driven shaft is obtained.
Communication from one pulley to the other is obtained by means of a belt, as
shown in Figure 1.
When a non elastic belt is used a weighted idle pulley rests upon the band to
keep it uniformly 'tight when changing speed.
Having now particularly described and ascertained the nature of our said inven-
tion & in what manner the same is to be performed, we would have it understood
that we do not confine ourselves to the exact arrangement of all the parts herein
described which may be varied without departing from the nature of our invention,
& we declare that what we claim is:
First. The sliding of a pair of bosses to & fro' upon both shafts simultaneously
but in opposite directions for the purpose, and operated in the manner, described.
Second. The manner of connecting the spokes to the sliding bosses & to the
segments of the rim; & the formation of teeth upon the inner edges of the
spokes which, being geared together, ensure uniformity of action & keep the rim
level.
Dated thin 15th day of November 1802
CHAS. J. BOYCE.
WILLIAM MARCH.