Improvements in Cycle Chain Adjustments.
Year: 1898

page_text: Date of Application, 19th Nov., 1898
Complete Specification Left, 25th Apr., 1899-Accepted, 27th May, 1899
Improvements in Cycle Chain Adjustments.
I, CHARLES BERTIE HARRISON, of Kensington Street Works, Aston near the
City of Birmingham, Manufacturer, do hereby declare the nature of this invention
to be as follows:
-
This invention has relation to that type of chain adjustment means for
velocipedes in which a disc plate is rotated within a strap made within or forming
a part of, the fork end fitting, within the longitudinal slot of which the end of
the spindle to be adjusted is traversed, with the rotatory motion of the disc plate
being converted into longitudinal movement which is imparted to the said
spindle, by a bossed plate or secondary disc, working within an excentric clearance
of the primary disc or cam plate and having an excentric hole in it, registering
through the greater part of its throw with the said fork end slot and adapted to
receive the spindle end.
The principal object of my invention in connection with such devices is to
provide means for preventing the pull of the chain disturbing the adjusted
positions of the parts.
In carrying out my invention, a strap or circular sinking is formed within or
provided at the fork end, said seating being horizontally crossed, in the direction
of a diameter, by the said slot which runs generally in line with the chain stay
member of the cycle frame, and within the said sinking, the primary disc is dis-
posed in such a manner as to admit of being rotated therein. The said disc is
pierced with an excentric clearance, adapted to receive the concentric boss of a
secondary disc plate having an excentric hole to receive the hub spindle, which
has an elongated hole or gap cut within it, engaged by a fixed stud or pin directed
from the bottom of the circular seating and through the clearance in the primary
or operating disc, which has a series of holes or sinkings to receive the nipples of
a fork spanner or other tool for effecting its turning.
The spindle hole in the secondary disc registers with the longitudinal slot in
the fork end, whilst the said secondary disc may swing upon the aforesaid pin as
a centre, so that on the rotation of the primary disc within its strap or seating,
the secondary disc, which constitutes the carrier for the spindle, has a combined
reciprocating and part-rotatory movement imparted to it, and longitudinally,
traverses the said spindle, for adjusting the chain, along the fork end slot within
which it is confined.
The parts are locked in their adjusted position by the screwing up of a nut upon
the extending end of the spindle, whereby the secondary disc is clamped against

page_text: the primary one and the last-named clamped in turn between the secondary disc
and the walls of the circular seating, against the inner side of which a collar or
second nut on the spindle is drawn or takes an abutment.
Dated this 18th day of November 1898.
Improvements in Cycie Unain Aqjustments.
I, CHARLES BERTIE HARRISON, of Kensington Street Works, Aston near the
City of Birmingham, Manufacturer, 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:
-
The invention has reference to that particular type of means for adjusting the
tension of the driving chains of cycles in which the parallel traverse of the spindle
to be adjusted is effected by the rotation of a system of disc plates within straps
or seatings formed within or attached to a part of the framing of a machine, and
has for its object, to provide means for preventing the pull of the chain disturbing
the positions of the adjusted parts or destroying the adjustment after it has been
obtained.
In the particular arrangement of mechanism to which my invention has
reference, the two ends of the spindle of the driven wheel of a safety bicycle pass
through excentric holes in secondary disc plates, which are themselves mounted
and are capable of rotation within excentrically disposed clearances made in
primary or operating discs carried by straps or within circular sinkings arranged
preferably on the outer sides of the slotted or forked end of the framing chain
stays. The parallel adjustment of the spindle is effected by rotating the operating
plates within their straps, this movement being communicated to the excentrically-
mounted secondary discs, the latter are carried round and the spindle, which is
constrained to move in a rectilinear or horizontal direction only, by the slots of
the fork ends, is adjusted according. The parts are locked in their adjusted
positions by the screwing up of nuts on the spindle ends, but even then, the
adjustment is liable to be disturbed by the pull of the chain being transmitted
through the spindle to the secondary discs, which, being free to rotate, may shift
round and thus allow the chain to slacken.
Figure 1 of the accompanying drawings represents an elevation of the fork end
fitfing of a safety bicycle fitted with chain adjustment of the type hereinbefore
referred to having means for preventing the disturbance of the adjustment—when
obtained by the pull of the chain. The lock nuts in this view are not shown
and the spindle is in section.
Figure 2 is a view showing the hub of the rear wheel and its fittings in plan
with one of the adjusting fork ends in section upon the dotted line, Figure 1.
Figure 3 is a like view as Figure 1, but showing the spindle in a different
position.
Figure 4 is an elevation of the inner side, with the parts in the same position
as Figure 3.
Figure 5 is a vertical section of Figure 3 upon the dotted line..
Figure 6 is an elevation of one of the fork end fittings separately, the adjusting
discs being removed.

page_text: Figure 7 is a vertical section of Figure 6, upon the dotted line.
Figure 8 is an elevation, edge view and vertical section of one of the primary
or operating disca separately.
Figure 9 represents like views of one of the secondary and spindle-carrying
discs separately.
The same letters of reference indicate corresponding parts in the several figures
of the drawings.
is the hub of the driven wheel of a safety bicycle with chain wheel a¹ and
spindle b, the position of which relative to the crank axle is to be varied for
altering the adjustment of the driving chain. Each end 6, of the said spindle
takes through the longitudinal slot e, of the fork end fitting and into an
excentric hole d', in a disc or secondary plate d, having a concentric boss d, on
its inner side taking within an excentrically disposed and all-through clearance c¹,
in the primary or operating disc e, which fits and admits of being rotated within a
corresponding seating, and is confined by the strap, coming upon the outer-
side of the fork end, with the said seating being crossed diametrally by the slot e',
within which the spindle is traversed, it being understood that the width of the
said slot is rather groater than the diameter of the spindle.
Extending outward from the seating is a stud or projection f, which passes
through the clearance e', and takes into an elongated hole d³, made in the direc-
tion of diameter within the disc d, from one edge nearly to the centre.
These stationary pegs f, engaging with the secondary discs d, as described
form both pivots about and upon which the said secondary discs swing and slide
in transferring the spindle from one position to another when either one of the
operating discs is rotated within its confined seating, and also, by always being
excentric to the said discs, prevent the inadvertent and independent turning of
the same within their bearings, in the primary discs and consequent displacement
of the spindle from its adjusted position through the pull exerted by the chain, in
driving, upon the said spindle and discs.
The operating discs may be provided with sinkings or holes such as g, adapted
to be engaged by the studs of a spanner for rotating, whilst the ends of the spindle
are provided with lock nuts h, by the screwing up of which, the primary and
secondary discs are clamped to the fork ends.
Iustead of preventing the disturbance of the parts from their adjusted positions
by means of studs projecting from the fork ends and engaging elongated slots
formed in the secondary discs, I may employ the converse arrangement according
to which the elongated slots are made within the fork ends and the studs which
engage therein project from the inner sides of the discs.
Figure 10 is an elevation of this modification: the spindle being shown in
section and its lock nuts removed.
Figure 11 is an elevation of one of the fork ends separately showing the vertical
slot formed therein and Figure 12 is a cross section upon the dotted line ³,
Figure 13 represents in elevation, edge view and vertical section of one of the
primary or adjusting discs, which are the same as that described in connection
with the first arrangement.
And Figure 14 represents like views of one of the secondary or spindle carrying
discs, showing the stud projecting from the inner side.
In these Figures 10 to 14, b is the spindle, e the fork end longitudinally
slotted at c, for the spindle to traverse within and recessed at to receive the
primary adjusting disc e. is the secondary disc, excentrically disposed within
a hole e, in the disc e, and being itself provided with an excentric hole d',
through which the wheel spindle passes, whilst projecting inwardly from this
disc is a stud or peg f, which, when the parts are assembled engages within a
small vertical slot ³, formed in walls of the fork end, whereby the independent
rotation of the spindle disc by the pull of the chain, is prevented,

page_text: Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim 18:
First: In cycle chain adjustments of the type herein described preventing the
displacement of the parts, or locking them in their adjusted position against the
pull of the chain by the employment of stationary studs such as f, on the fork
end engaging with elongated holes such as , in the secondary spindle carrying
discs d, and on which the said discs, make a compound movement, or both
swing and slide, in transferring the spindle from one position to another when
the operating discs are turned, and which also prevent any independent rotation
of the said dises d, within their bearings, substantially as described and set forth
in Figures 1 to 9.
Secondly: In cycle chain adjustments of the type herein described, preventing
the displacement of the parts, or locking them in their adjusted positions against
the pull of the chain, by the employment of studs or projections such as f, upon
the spindle-carrying discs engaging with slots in the fork end, with the parts
arranged and operating substantially as described and set forth in Figures 10
to 14.
T
" 1
1000