Improvements in Cycle Chain Adjustment.
Year: 1896

page_text: Date of Application, 9th Nov., 1896
PROVISIONAL SPECIFICATION.
Improvements in Cycle Chain Adjustment.
I, ROBERT ALFRED MARPLES, of Merridale, Oakfield Road, Selly Park, near the
City of Birmingham, Electrical Engineer, do hereby declare the nature of this
invention to be as follows:-
This invention relates to cycle chain adjustment, or means for adjusting the
tension of the chain which communicates motion. from the driving to the driven
wheels, and consists of a device secured at the ends of the back forks at the
junction of the back stays with the chain stays whereby the distance between
the crank axle and the back wheel hub is altered or increased or diminished and
has for its object, a neat and efficient adjustment with no outstanding parts and
with portions of the mechanism hidden or concealed.
Situated at the outer ends of each of the chain stays, near or at their junctions
with the back stay, is a longitudinally slotted plate, through the slot of which
the shank of an inside screwed button or mushroom-headed stud passes and takes
upon the screwed end of the non-rotating spindle of the back wheel hub. The
shank or stud of the button is of a diameter corresponding to the width of the
slot in which it traverses.
The neck of the stud and the end of the spindle fitted therein have coincident
screwed holes wherein the end of the longitudinally disposed drawing up pin
takes, with the head of the said pin coming upon a bearing plate at the end of
the slotted plate, whilst the shank takes through a plain hole formed in the bearing
plate, lignable with the centre of the slot and the holes in the spindle and stud.
Taking upon the screwed end of the spindle, on the inner side of the slotted
plate, is a lock nut, which, on being screwed against the inside face of the plate,
securely clamps the spindle in its adjusted position.
Instead of a slotted plate, a box end with slotted sides may be employed, but in
such a case, the said end is fitted with a strengthening sleeve or liner for taking
the lateral pressure exercised by the lock nut against the sides of the box end.
Assuming that the screwed spindle ends have been placed within the slots, with
the lock nuts run back slack, and with the drawing up screws, withdrawn, then
screw the buttons upon the ends of the said spindle, until the plain holes in the
said ends come coincident with the screwed holes in the studs or shanks. Then
pass the drawing up screws through the holes in the bearing plates at the ends
of the slots (said bearing plates being preferably enlarged or expanded) and pass
the ends into the coincident holes in the studs and spindle; then rotate the screws
to the desired extent until the required adjustment is obtained, when the lock
nuts are screwed up to the sides of the slotted plates or box ends, when the whole
of the parts are clamped in their adjusted positions.
Each of the outer sides of the slotted plates are marked with a graduated scale,
whilst the buttons may have pointers to indicate when both ends of the spindles
have been drawn back to the same extent.

page_text: By constructing a chain adjustment as described, the whole of the parts are
enclosed between the inner sides of the slotted plates.
Dated this 7th day of November 1896.
Improvements in Cycle Chain Adjustment.
I, ROBERT ALFRED MARPLES of Merridale, Oakfield Road, Selly Park, near the
City of Birmingham, Electrical 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:-
This invention relates to cycle chain adjustments, or means for adjusting the
tension of the chain which communicates motion from the driving to the driven
wheels, and consists of a device secured at the ends of the back forks at the
junction of the back stays with the chain stays, whereby 'the distance between
the crank axle and the back wheel hub, is altered or increased or diminished,
and has for its object, a neat and efficient adjustment with no outstanding parts
and with portions of the mechanism partially boxed in.
Figure 1 of the accompanying drawing represents an elevation of a cycle chain
adjustment constructed and arranged according to one form of my invention.
Figure 2 represents a vertical section of the same upon the dotted line c.
The outer end of each chain stay a, near or at their junctions with the back
stay b, is fitted with a longitudinally slotted plate e, through the slot, of which
the plain-bored shank ', of a button or mushroom-headed stud i, passes and takes
upon the screwed end e, of the non-rotating spindle e, of the back wheel hub.
The shank or stud 2 of the button is of a diameter corresponding to the width of
the slot in which it traverses.
The neck of the stud and the end of the spindle fitted therein have coincident
screwed holes 23, e3, wherein the screwed end f', of the longitudinally disposed
drawing up pin or bolt f, takes, with the head f, of the said pin coming upon a
bearing plate g, at the end of the slotted plate, whilst the shank takes through a
plain hole g', formed in the bearing plate, lignable with the centre of the slot
and the holes in the spindle and stud, and terminates in a hole made to receive it
at the inner end of the slot.
Taking upon the screwed end of the spindle, on the inner side a³, of the slotted
plate c, is a lock nut j, which, on being screwed against the inside face of the
plate, securely clamps the spindle in its adjusted position.
Instead of a slotted plate, a box end with slotted sides may be employed, fitted
with a strengthening sleeve or liner for taking the lateral pressure exercised by
the lock nut against the sides of the box end.
Assuming that the screwed spindle ends e, have been placed within the slots,
with the lock nuts j, run back slack and with the drawing up screws f, withdrawn,
then place the buttons i, upon the said spindle ends until the plain holes e³, in
them come coincident with the screwed holes 22 in the studs or shanks. Then pass
the drawing up screws f, through the holes in the bearing plates at the ends of
the slots (said bearing plates being preferably enlarged or expanded) and pass
the ends into the coincident holes in the studs and spindle; then rotate the
screws to the desired extent until the required adjustment is obtained, when the

page_text: lock nuts i, are screwed up against the inner sides of the slotted plates or box
ends, when the whole of the parts are clamped in their adjusted positions.
Each of the outer sides of the slotted plates may be marked with a graduated
scale k, whilst the buttons may have pointers m, to indicate when both ends of
the spindles have been drawn back to the same extent.
Figure 3 represents an elevation of a cycle chain adjustment constructed and
arranged according to a modification of my invention."
!
Figure 4 represents an end elevation of the said adjustment but with the
bearing plate fitting on the end of the left hand chain stay removed.
Figure 5 is a transverse vertical section upon the dotted line 2, Figure 3.
Figure 6 represents the spindle and its locking nuts (in elevation on one end
and in section on the other end) separately.
Figure 7 is a longitudinal vertical section of the slotted boxed end of the chain
stay which carries or is fitted with the several components of the adjustment.
Figure 8 is an end view of the said stay and
Figure 9 is a vertical section thereof upon the dotted line a', Figure 7.
Figure 10 represents in front elevation and edge view, one of the draw bolts,
with its nut and bearing plate.
Figure 11 is an end view of the draw bolt separately, and
Figure 12 represents an elevation and a vertical section of one of the bearing
plates, separately.
The same lettens of reference indicate corresponding parts in the Figures 2 to 12
of the drawing.
The outer end a', of each of the chain stays a, at or contiguous to its junction
with the back or seat b, is longitudinally slotted at a, upon the inner side a³ and
gapped at a', to an extent about equal to double the width of the slot, upon the
outer side a, whilst the extreme end a", is left entirely open. Located within
the interior of this slotted and gapped end is a liner or strengthening piece c,
slotted at 3, coincident with the slot 2, and having a solid inward end e, which
closes or boxes in the said part a', of the fork, so that there is thus formed a
partially enclosed recess or chamber e, within and adjacent to which the several
parts of chain adjustment are located. The liner has a lip e, which passes up and
is rivetted and brazed to the seat stay b, and so gives great strength to the fork.
d is the hub of the back wheel, running on ball bearings 2, disposed between
the ball races of the cups d, of the said hub, and the cones el, on the spindle e,
each screwed end e, of which takes through the gaps as, &, of one fork end and
liner, and extends into the boxed recess, after passing through the ring or
eyed plate f, carried at the inner part of the screwed draw bolt f, whose outer
end passes through the bearing plate g, seated within a slight sinking a', in
the outer extremity of the fork, and then receives the drawing-up nut h, by the
rotation of which the draw bolt and the end of the spindle carried by it are
correspondingly traversed within the recess, so that by the turning of both
nuts h, the distance between the chain wheel 3, of the hub and the driving wheel
of the bicycle is increased or decreased and the tension of the driving chain adjusted
accordingly.
Threaded upon each screwed part e, of the spindle and located between the hub
and the inside face a', of the fork end, is a shoulder or abutment nut i, whilst
taking upon the outward extremity of the said screwing, but coming within the
recess, is a lock nut j, so that when a necessary adjustment of the chain has
been effected, the nuts i, are screwed outwardly until jambed against the inner
faces of the fork ends, whilst the lock nuts j, are screwed inwards or in the
reverse direction and clamp the eyed plates or rings of the draw bolts against
the inside of the recesses in the said fork ends, the nuts i, forming abutments or
shoulders for the backs of the fork ends to draw up against, thereby rigidly
locking the parts of the adjustment in their desired positions, with the strengthen-
ing plates or liners taking the whole of the lateral pressure exercised by the said.
lock nuts in thus locking the adjustment.

page_text: By constructing a chain adjustment as described the whole of the parts are
enclosed within the slotted fork ends.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is :-
First. Clamping an end or both ends of the back wheel spindle of a cycle to the
fork end by or between a locking nut and a shoulder nut, coming and being
tightened or clamped respectively against the inner side of the fork end and the
outer side of the fork end, or against the ring, eyed plate or equivalent part of a
draw-bolt or like part of a chain adjustment, substantially as described and set
forth.
Secondly. The recessed, sunken or trouglied construction of the chain-adjustment
longitudinally-slotted fork ends of cycles, provided with an internal and corre-
spondingly slotted liner or strengthening plate for taking the lateral pressure of
the lock nuts, substantially as described and set forth.
Thirdly. The arrangement and combination of the parts of cycle chain adjust-
ments and fork ends, substantially as described and set forth in Figures 1 to 12.
Fourthly. The improvements in cycle chain adjustments, substantially as
herein described.
Dated this 6th day of August 1897.
ROBERT ALFRED MARPLES,
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.
ROBERT ALFRED MARPLES,
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.