Improvements in the Adjustment of Cycle-gear-chains.
Year: 1893

page_text: Date of Application, 7th July, 1893
Complete Specification Left, 7th Apr., 1894-Accepted, 2nd June, 1894
PROVISIONAL SPECIFICATION.
Improvements in the Adjustment of Cycle-gear-chains.
I, George Frederick Bull, of 13 Priory Street, Coventry, Mechanical
Draughtsman, do hereby declare the nature of this invention to be as follows:-
This invention has for its object the adjustment of the gear-chains of cycles
that is to say the tightening or slacking of such gear chains, on the gear-wheels.
In carrying out my invention I proceed in the following manner :--I cut form
or otherwise provide toothed racks on the internal edge faces of the back slots of
cycle-framing; I next provide the hub spindle one end of such hub-spindle is
screwed continuously reaching the centre of said spindle (or thereabouts) as a means
of adjustment for ball-bearings, the other end of spindle is connected permanently
to a ball-bearing, a screwed end projecting beyond such ball-bearing a suitable
length to receive lock-nut and washer.
I next provide an adjusting pinion pierced with a central threaded hole and thread,
such adjusting pinion over the screwed end of spindle tightening the face of the
pinion against the outer face of fixed ball-bearing.
I next provide the moving or adjusting ball-bearing and screw it over the
adjusting screwed end of spindle, I then provide a second adjusting pinion and
screw it to rest clear of the outer face of adjusting ball-bearing.
I next provide a locking washer which, consists of a piece of metal, the horizontal
configuration of which presents to view a parallel slot with half round ends from
one end of such slot projects a wide bearing-face and from the other end projects a
reduced bearing-face but of increased thickness.
In using the spindle carrying the two pinions as hereinbefore described, the
pinions are geared into the racks formed in the back slots of cycle framing, the
spindle being then revolved until the adjusting pinions carry the spindle into
the root of slot; the spindle would be secured to the cycle framing in the following
manner:-
Over that end of spindle carrying the fixed ball-bearing I pass a suitable washer
and over the washer I screw a suitable nut and adjust the nut loosely on the face
of the washer.
I next take the adjusting washer and pass its slot over the adjusting end of
spindle until the small end of said washer takes a bearing against the outer-face of
adjusting pinion, the upper wider surface of washer being thinner than the narrow
thickened part does not touch the outer face of framing.
a foot-
I next provide any suitable nut (by preference a nut combined with
rest) and then by rotating the foot-rest nut or other nut over the screwed
adjusting end of spindle, I press the adjusting washer on to the face of pinion,
thereby obtaining a means of revolving the spindle together with the adjusting
pinion attached thereto, the upper or larger face of adjusting washer would at this
stage move easily over the outer face of frame.
Pressure exerted to revolve the nut or the step and nut would revolve the spindle
together with both ball-bearings and at the same time revolve the two adjusting
pinions over the racks.
It will be apparent that such revolution of the adjusting pinions over the
toothed racks would move the spindle carrying the chain wheel away from the
front chain-wheel thus stretching or tightening the chain over the two chain
wheels.
When the chain had been sufficiently stretched the spindle would be adjusted
and secured where moved, by means of the nut at non-adjustable end of spindle,

page_text: such nut being tightened rigidly against the face washer, the adjusting washer
would then be turned upside down so that the large thin bearing surface of such
washer could be compressed against the outer face of frame slot by means of the
ordinary nut, or foot rest nut.
COMPLETE SPECIFICATION.
Improvements in the Adjustment of Cycle-gear-chains.
I GEORGE FREDERICK BULL of 13 Priory Street Coventry Mechanical
Draughtsman 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 :-
This invention has for its object the adjustment of the gear-chains of cycles, that
is to say, the tightening or slacking of such gear-chains on their gear-wheels.
I will now proceed to describe with reference to the accompanying drawings the
manner in which my invention is constructed and used.
Figure 1 represents the hub-spindle, ball-bearings, pinions and other connections
together with dotted-in back slot cheeks of cycle framing.
Figure 2 represents an end elevation of Figure 3.
Figure 3 represents a front elevation of the toothed back slot of a cycle-frame
to which is connected the hub-spindle by means of the adjusting-pinion and rolling-
lever.
Figure 4 represents a front view of rolling-lever or washer.
Figure 5 represents a side view of Figure 4.
Figure 6 represents a front view similar to Figure 3, excepting that the pinion
is shewn rolled outwards to tighten the gear-chain.
Figure 7 represents plan of washer used on right hand side of Figure 1.
Figure 8 represents an edge view of Figure 7.
Figure 9 represents a plan of pinion.
Figure 10 represents an edge view of Figure 9.
In carrying out my invention I cut, form, or otherwise provide toothed racks on
the faces of the back-slots of cycle frames; a Figures 1-2-3 and 6 represent the
back ends of cycle frame combined with the cheeks b, within which is provided the
slot d; the toothed racks may be formed by removing a portion of the upper edge e
or the lower edge f of slot d; the providing of the rack by cutting it on the upper
edge e or on the lower edge f, I consider to be the simplest form of construction
because the rack so cut out of the solid cannot jerk loose, nevertheless I in some
cases (where my improved chain adjustment is applied to old machines and where
my improved adjustment has to be applied to new machines already made up
and stocked) prefer to provide a separate rack and secure such separate rack over
either the uncut edges e orf of the slot d or I can secure a loose rack to either side-
face of the cheek b.
I next provide the hub-spindle 9, one end of such spindle g is screwed con-
tinuously towards the centre, reaching the point h or thereabouts, such screwed
part being provided as a means of adjustment for the ball-bearing j; the other end
of spindle is consolidated with ball-bearing k, a screwed end projecting beyond the
ball-bearing k to receive lock-nut, lock-lever or other equivalent fastenment.
1 next provide the adjusting pinion m and pierce it with a central threaded hole

page_text: suitable to screw over the end 1, or in lieu of the threaded hole I provide a
D shaped clearance hole such latter is the method of attachment shewn on the
drawings, the pinion m would be passed over the end of spindle g to bear against
the outer face of ball-bearing k as shewn at Figure 1.
I next provide the moving or adjusting ball-bearing j and screw it over the end n
of spindle I then provide a second adjusting pinion o aud screw it over the end n
of spindle 9 to rest on the outer face of ball-bearing j.
I next provide a locking-washer or equivalent locking-lever pierced with a
D shaped hole as shewn in detail at p Figure 4.
In using the spindle carrying the two pinions as hereinbefore described, the
pinions m and o are geared into the two racks formed in or on the two back-slots of
cycle framing, the spindle being then revolved until the adjusting pinions carry the
spindle into the root of slot.
The hub-spindle would be actuated within the cycle frame back-slots in the
following manner :-
Over the adjusting end of spindle carrying the fixed ball-bearing k and pinion m,
pass the rolling-lever or washer g and pass its slot p over the adjusting end of
spindle until the circular end takes a flat bearing against the outer face of adjusting
pinion m, the upper or handle end of adjusting lever may be thinner than the
lower circular part, I next provide any suitable nut such as shewn at s or in lieu of
such nut I may provide an extension that will form a foot-rest and also act as a nut;:
the rolling-lever can be moved from the position shewn at Figure 3 into the position
shewn at Figure 6 thereby rolling the adjusting pinions m and o along the cheek-
racks, thus moving the hub-spindle and the chain-wheel or wheels connected thereto
farther from the front chain wheel or wheels and thereby tightening the chain or
chains; by placing a washer between the adjusting pinion m and the face of the
rolling-lever or washer g at the part of the spindle marked t, the face of the rolling-.
lever g would be kept clear of the face b of frame-slot d the nuts or its equivalent
could be used as a means of rolling the pinions m and o into their ratchets.
The hub-spindle when moved into a position to tighten the chain or chains could
be locked in such position by means of the nut u or the nut s or by means of both
of such nuts or end lockings.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1st. The invention as illustrated and described, for use in the manner decribed.
2nd. The providing of toothed or ratchetted surfaces in or on the back-slots of
cycle-framing for use with toothed pinions attached to a cycle-hub-spindle, as a
means of tightening the driving chain or driving chains of a cycle, as illustrated
and described.
3rd. The providing of movable toothed ratchets for use in or on the back-slots of
cycle-framing in combination with pinions secured to a hub-spindle, as a means of
tightening the driving-chain or driving-chains of a cycle.
Dated this 6th day of April 1894.
Witness:
GEORGE FREDERICK BULL.
ALFRED WILLIAM TURNER,
Patent Agent,
Cobden Buildings, Corporation Street, Birmingham.