Improved Fork End Chain Adjustment for Cycles and other like Propelled Vehicles.
Year: 1898

page_text: Date of Application, 16th Feb., 1898
Complete Specification Left, 25th Oct., 1893-Accepted, 11th Feb., 1899
PROVISIONAL SPECIFICATION.
Improved Fork End Chain Adjustment for Cycles and other like
Propelled Vehicles.
ALBERT THOMAS HARRIS, "Highfield," Station Grove, Wembley, Middlesex,
Cycle Engineer, do hereby declare the nature of this invention to be as follows:
My improvement consists in a parallel adjustment from one or both sides of the
wheel or wheels, also for locking tension independent of side nuts. It is actuated
by the spindle being turned, the said spindle having toothed wheels on the same,
either cut on the spindle, or removable, but so fixed as to revolve with the same,
these teeth engages in racks placed in such a position as to draw wheel or wheels
backward or forward & so alter the tension of the chain, or band. The rack is on
the compression stay on the inside of one of the prongs of the fork end, between
which the spindle revolves, the other prong being smooth as to allow a slide to
work between, this slide has a hole the size of the spindle, the same hole being
countersunk concentric for the toothed wheel to turn in enough of the slide being
cut away as to allow the teeth to protrude into the rack, thus when either the
spindle is turned, or one of the toothed wheels, or the slide is pushed backward or
forward it acts simultaneously the other side. The slide may be drawn or pushed
by a screw or lever the same acting as a lock to prevent it slipping back or forward,
or the said screw or lever may act upon the spindle or the teeth of the toothed
wheel. The toothed wheel may come directly next to the cone or there may be
a washer fixed in the same manner on spindle so as to turn with same so as not
to alter the bearings if the cones are of the screw on principle, or the washer &
toothed wheel may be made in one piece, the washer part being large enough to
clamp on the fork ends, when side nuts are screwed up. Or the toothed wheel may
act as washer, if so the rack would be cut accordingly on the side of fork ends.
It is only necessary that the locking may be on one side of the wheel only.
Dated this 16th day of February 1898.
COMPLETE SPECIFICATION.
Improved Fork End Chain Adjustment for Cycles and other like
Propelled Vehicles.
I; ALBERT THOMAS HARRIS, of Highfield, Station Grove, Wembley, Middlesex,
Cycle 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:
Mr invention relates to an improved device for adiusting the tension of cycle

page_text: and like chains and has for its object to enable such adjustment and the locking
of the adjustment to be easily and rapidly effected from either side of the wheel,
and so that the spindle will always occupy parallel positions.
For this purpose I provide the slotted ends of the backstays with racks, with
which engage pinions located upon the ends of the wheel spindle, which extend
through the slots. Each extremity of the spindle is furnished with a square or
the like for the purposes of adjustment and with a nut and washer for locking the
adjustment. In a modification the extremities of the wheel spindle are supported
in slides or bearing blocks fitted to slide in the slots and serving for the reception
of the pinions gearing with the racks.
Referring to the accompanying drawings,
Figure 1 represents a side elevation of my improved adjusting device, and
Figure 2 is an end elevation of the same.
Figure 3 shows a side elevation of a modified arrangement of this device, and
Figure 4 is an end elevation of the same.
Figures 5, 6 and 7 show a back view, end elevation and plan respectively of the
bearing block.
Like letters refer to corresponding parts in all the figures.
In the end of each back stay A of the cycle frame, I secure (Figs. 1 and 2) or
cut (Figs. 3 and 4) a rack barranged either above or below the usual slot a. With
each of these racks b engages a pinion c located upon the end of the wheel spindle B.
The said pinions may be cut upon the ends of the spindle but I prefer to make
them separate in which case I make the said ends of the spindle of D or other
non-circular section and make the central holes in the pinions of the same form
so that when fitted together the pinions and spindle are incapable of independent
rotation though the pinions can be moved lengthwise on the spindle when required.
The teeth of the respective racks b and pinions c should be carefully aligned to
ensure the spindle B standing exactly at right angles to the plane of the chain.
Upon each end of the wheel spindle B, (which terminates in a square or like
formation d for enabling the spindle to be turned by means of a spanner or the
like,) I furnish a nut e and washer e' which, when forced against the outer face of
the end of the stay A will securely lock the said spindle in position.
In Figures 3 and 4 each end of the wheel spindle B is held in a slide or flanged
bearing block f capable of sliding in the slot a at the end of the back stay. The
flange of this block fits against the outer face of the stay end and is designed to
serve as a seat for the before mentioned nut e and washer e¹. Between the two
parts fl of this bearing block, (Figures 5, 6 and 7) is located the pinion c which is
adapted to gear with the rack 6 at the upper side of the slot a, while the said
parts fare adapted to slide upon the lower side of the slot a.
The bearing blocks f may be drawn or pushed by a screw which also acts as a
lock to prevent backward or forward slipping, or the screw may act directly upon
the spindle, after the manner of existing chain adjusting devices not provided with
the herein described rack and pinion device.
The pinions c or stay ends may come directly next to the bearing cones g, but
I much prefer to introduce a washer between these parts. The washers h are
made of suitable size to bear against the stay ends and are fitted on to the wheel
spindle so as to rotate therewith, though free to move lengthwise thereon. Thus
the washers h (instead of the cones g,) take the friction against the stay end when
the spindle B is rotated, and the risk of altering the adjustment of bearings in
which the cones screw along the spindle, is avoided. The washer h may be made
in one piece with the pinions e as in Fig. 4; or the racks may be formed on the
inner faces of the stay ends, when the pinions themselves will act as washers.
The construction may be similar at each end of the wheel spindle or the operating
device may be applied at one end only.
After loosening the nuts e the tension of the driving chain may be adjusted by
turning the spindle B with a spanner applied to either extremity thereof or by
operating the screw device. This operation causes the two pinions carried by the

page_text: spindle B to travel along the racks b, thereby causing the said spindle to move in
the slots a and to move equal distances at each end. The chain is tightened or
loosened according as the spindle B is moved backward or forward in the slots a.
After the chain has been adjusted the nuts e are re-tightened to lock the spindle
in position. With the arrangement shown in Figs. 1 and 2, which I prefer,
tightening the nuts e has the effect of closing the sides of the hollow ends of the
stays A on to the pinions c which are thereby gripped and accidental transmission
of the rotary motion of the nuts to the pinions and spindle (which would disturb
the chain adjustment) is prevented. In the arrangement shown in Figs. 3 and 4
the pinions are made thinner than the stay ends so that the grip of the nuts and
washers is taken by the ends alone.
My invention may be applied in other suitable cases in a similar manner.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I would have it understood
that I am aware that it has already been proposed to provide the stay ends with
racks and the wheel spindle with pinions for chain adjusting purposes and I
therefore do not broadly claim such construction, but what I do claim is :-
-
1. A device for adjusting the tension of cycle and like chains comprising, a
rack fitted or formed in or on each stay end, a wheel spindle, having its extremities
of square or like formation, and adapted to pass through slots in the stay ends, a
pinion formed on or fitted to each end of the said spindle so as to turn therewith,
such pinions engaging in the said racks, and lock nuts on the end of the spindle,
all combined arranged and adapted to operate substantially as set forth.
2. In a chain adjusting device of the kind referred to in Claim 1, the employ-
ment of bearing blocks such as f on the spindle B between the stay ends and the
lock nuts, and adapted to slide in the slots a, substantially as and for the purpose
set forth.
3. In a chain adjusting device of the kind herein referred to, the employment
of washers such as h on the spindle B between the bearing cones y and the stay
ends, substantially as and for the purpose set forth.
4. In a chain adjusting device of the kind herein referred to, placing the racks
in the ends of the stays so that when the lock nuts are tightened the pinions are
gripped, substantially as and for the purpose set forth.
5. A device for adjusting the tension of cycle and like chains constructed
arranged and adapted to operate substantially as herein described with reference
to Figs. I and II of the accompanying drawings.
6. A device for adjusting the tension of cycle and like chains constructed
arranged and adapted to operate substantially as herein described with reference
to Figs. 3, 4, 5, 6 and 7 of the accompanying drawings.
7. The combination with the device for adjusting the tension of cycle and like
chains referred to in the preceding claims, of existing screws adapted to act on the
wheel spindle or the bearing blocks, substantially as and for the purpose set forth.
Dated this 24th day of October 1898
G. DOUGLAS LEECHMAN,
18, Hertford Street, Coventry, 75, Chancery Lane, London, W.C., and
9, Exchange Chambers, New Street, Birmingham,
Patent Agent for the Applicant.