A NEW OR IMPROVED DIFFERENTIAL i DRIVING GEAR FOR VELOCIPEDES AND OTHER MACHINES
Year: 1883

page_text: LETTERS PATENT to Charles Vernon Boys of No. 7 Dorset Square in the
county of Middlesex for an Invention of A NEW OR IMPROVED DIFFERENTIAL
i DRIVING GEAR FOR VELOCIPEDES AND OTHER MACHINES
PROVISIONAL SPECIFICATION left by the said Charles Vernon Boys at the
Office of the Commissioners of Patents on the 31st October 1883.
CHARLES VERNON BOYS of No 7 Dorset Square in the County of Middlesex
"A NEW OR IMPROVED DIFFERENTIAL DRIVING GEAR FOR VELOCIPEDES AND OTHER
MACHINES
"
:
'My invention relates to a differential driving gear applicable to velocipedes and
other machines, the object which I have in view being to avoid toothed gearing
and the noise and backlash which result from its use. For this purpose, I fix on
each of the two axles or wheels that are to be driven a disc with a conical edge,
and in the V hollow between those conical edges I lodge a number of balls.
I surround these balls by a ring which is driven by the power, and within this
ring, there are formed sloping recesses, one for each of the balls employed. When
this ring is caused to revolve, the balls, being to a certain extent wedged in their
recesses, drive the two conical edged discs, but one of these may revolve faster
than the other, each ball in that case turning on an axis situated in the dividing
plane of the discs. In order to counteract the outward thrust produced by the
wedging action of the balls, I provide two other sets of balls, each set situated
between a sloping shoulder on the outside of the disc and a shoulder of the ring.
According to a modified arrangement, which dispenses with the balls for resisting
outward thrust, I make the two driven discs with flanges projecting towards each
other, but the flange of the one larger than that of the other, so as to overlap it,
leaving an annular space between the two. Into this space, from ono side, an
annulus of the driven wheel projects, this annulus having sloping recesses containing
two sets of balls, those of each set wedging into V hollows between conical edges
formed on the flanges of the two driven discs.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Vernon Boys in the Patent Office on the 30th April
1884.
CHARLES VERNON BOYS of N° 7 Dorset Square, in the county of Middlesex
A NEW OR IMPROVED DIFFERENTIAL DRIVING GEAR FOR VELOCIPEDES AND OTHER
MACHINES.
My invention relates to a differential driving gear applicable to velocipedes and
other machines, the object which I have in view being to avoid toothed gearing
and the noise and backlash which result from its use. For this purpose, I construct
differential driving gear as I will explain, referring to the accompanying drawings.
Fig. 1 is a longitudinal section through a pair of tubular axles connected by the
differential driving gear, and fig 2 is a transverse section. To each of the two
tubular axles A and A¹ is attached a disc B and B¹ having a conical edge, these
edges presenting together a V-groove in which are a number of balls C. The
annular wheel D, which is driven by a chain or otherwise, has in its inner periphery
concave recesses E, one for each of the balls C. Through the two discs B'B' is
passed a bolt F, having a head G and a collar E secured by a lock nut K, and balls L
are placed between the back of the disc B and the head G and also between the
back of B' and the collar H. When the wheel D is made to revolve in either
direction, the balls Care, by the slope of the recesses E caused to wedge themselves
in the V-hollow between the discs B B¹, taking such frictional hold as to causo
them and their axles A A' also to revolve. Should one of these axles, have to
revolve faster than the other, as is the case when a velocipode or other vehicle, to
the wheels of which the axles are connected, is in the act of turning, then, each of
the balls C is caused to revolve on an axis so situated as to allow for tho edge
of one of the discs travelling faster than the other. The balls L rolling between
the discs and the head and collar of the bolt F, are subject to the outward thrust
resulting from the tendency of the balls C to wedge the discs apart, and serve to
counteract the friction that would otherwise be occasioned if the discs bore against
stationary surfaces. When the parts become loose by wear, they can be adjusted
by screwing up the nut K.
Figs 3 and 4 shew a modified construction. In this case, the driving wheel D
at one side and a cap D¹ on the other side enclose the antifriction balls L which
run under sloping shoulders of the discs B-B¹. The cap D¹ is connected to D by
screwing both to a middle ring D' in which are formed the hollows for the balls Č.
The tightening up for wear is effected by screwing D' a little farther on D', and
both D and D are prevented from becoming loosened or unscrewed by screw pins d.
Sometimes it is desired to drive only in one direction, allowing slip in the opposite
direction. In such a case, the ball recesses may be as at E¹, made to form a stop
for the balls, so that they cannot become jammed on that side of the recess. Or
the recesses may have pins E' inserted to form stops for the balls. It may be
convenient to have an even number of recesses part of them like E' alternating
with those like E, or with others like E¹ having their stops to the opposite hand.
By introducing the balls into the recesses of the one kind or the other, the
coupling can be suited for driving in either direction or in both. According to the
modification shewn by figs. 5 and 6, the balls C are wedged outwards and the
V hollow between the discs B and B', and the antifriction balls L are held between
the discs and external caps screwed into the driving wheel D. The central part D'
which presents flat faces for the balls C to bear on, is conveniently made as a
separate piece from D so that it can be finished and hardened before it is put in
its place.

page_text: Having thus described the nature of my invention and in what manner the same
is to be performed, I claim :—
The construction of differential driving gear wherein balls engaged in recesses of
a driving wheel are pressed by the slope of these recesses into the V groove formed
between the coned edges of discs attached to the two differentially driven axles,
substantially as herein described.
In Witness whereof I the said Charles Vernon Boys have hereunto set my
hand and seal this twenty-eighth day of April in the year of our Lord, ono
thousand eight hundred and eighty-four.
DATO
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