Improvements in Chain-driven Velocipedes.
Year: 1890

page_text: The decision of the Chief Examiner, acting on behalf of the Comptroller, of the
18th day of September 1894, allowed, under Section 18 of the Patents, &c.
Act, 1883, an Amendment of this Specification.
Date of Application, 9th June, 1890
Complete Specification Left, 9th Mar., 1891-Accepted, 6th June,
1891
Improvements in Chain-driven Velocipedes. .
I PHILIP LOUIS RENOUF of Stoke Green Coventry in the County of Warwick
Engineer do hereby declare the nature of this invention to be as follows:-
The object of my invention is to provide suitable means for taking up the
slack of the chain of a velocipede in such a way that the axes of the two chain-
wheels remain parallel.
For this purpose where the chain wheel bracket is not detachable from the
frame the back frame is made in two parts and joined in two places one joint
One chain wheel
forming a hinge and the other joint forming a circular slide.
is mounted on each half of the frame and the motion of one part along the
slide being radial from the hinge joint provides the requisite adjustment. By
using the hinge as the joint of the back and upper forks a separate part and
thus also weight and complication are avoided.
Where the chain wheel bracket is not a fixture to the frame the eccentrie
adjustment is used; but instead of employing as hitherto one large eccentric in
the centre of the bracket and which is liable to be twisted by the side strain
of the chain and the construction of which involves the use of separate and
overhung bearing cups I form my 'bearing out of one piece provided with two
eccentrics a considerable distance apart; by leaving a space equal in width to
the straps of the eccentrics between the latter and the bearing ends it will he
found possible to mount the bracket on the frame or detach it from the same
without taking the bearings to pieces though the eccentric be but slightly
larger in diameter than the bearing ends. The straps may be provided with
split lugs capable of gripping the eccentrics or they may be slotted and provided
with lock screws inserted in the eccentrics, or else the latter may be split and
expanded so as to fit into the straps tightly.
1000
POPPLEWELL & Co.,
17 & 18, Southampton Buildings, London, W.C.,
Agents for the Applicant.
COMPLETE STUITION
Improvements in Chain-driven Velocipedes.
I, PHILIP LOUIS RENOUF of Stoke Green, near Coventry in the County of
Warwick, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be perforined to be particularly described and ascertained
in and by the following statement :-
The object of this invention is to provide suitable means for taking up the slack

page_text: of the chain on velocipedes in such a way that the axes of the two chain-wheels
remain parallel.
Referring to the drawings accompanying these Specifications, Fig. 1 shews &
side-elevation of the back part of the frame of a safety-bicycle, in which
A represents the chain-wheel bracket rigidly attached to the frame. D is one
of a pair of stiff stays which are hinged to the main frame at E, and support the
driving hub spindle and chain-wheel at their lower extremities B; the end of
the lower or chain stays, of which one is shown at C, are slotted; these slots form
ares about E as a centre.
The back hub spindle which passes through the ends of the stays D, at B, and
through the slots of the chain stays C as well, is secured in position by lock nuts
in the usual way; thus tying the various stays together.
To adjust the chain, these nuts are unscrewed, the back hub is moved backwards,
along the slots in C, together with stays D, and the nuts tightened up again.
As stays Dalways follow the hub pin at B and therefore bear the vertical strain,
the slotted ends of the chain stays need not (as is otherwise necessary) to be made out
of comparatively heavy stampings or castings which have to be brazed to the frame;
they may be formed by merely flattening and pressing the tube of which the chain
stays are usually formed, thus economising by weight and expense.
Where the bottom or chain-wheel bracket is moveable I prefer the eccentric
method of adjustment. Where this method has been employed hitherto, there has
been only one eccentric, which though of comparatively large diameter afforded but
a very narrow surface, and was liable to be twisted laterally; or it has been found
necessary to build up the bracket out of three pieces, at least, thus increasing the
cost of construction and incurring great risk as to stability. I therefore furnish
the frame of the machine with a pair of circular straps B, B1 (Figs. 2, 3 and 4) as
wide apart from each other as the chain stays C, C, to which these straps are
attached, will allow; A in the same figures shews the bottom bracket bearing
furnished with a pair of eccentrics D, DI which fit into these straps. Referring to
Fig. 3, a side elevation of the bracket, the straps are furnished with a split lug E
and nip-screw F; it will be evident that the bracket can be moved backwards and
forwards by turning the eccentrics to the required distance and then locking them
hy tightening the straps by means of the nip-screws at F.
Fig. 4 shows a plan of the bracket whilst being inserted through the strap joint;
it will be seen that in order to enable the bracket and the two eccentrics to be
made out of one single piece of metal, the distances marked l. m. and n. o. should be
equal; where this is the case the holes in the eccentrics need only be large enough
to enable the extreme ends of the bracket to pass through them.
Instead of locking the eccentrics by means of closing or pinching in the straps,
the eccentrics may be capable of expansion, as shown in Fig. 5, where this action
is obtainable by means of a taper screw or bolt, inserted through a hole at G.
Another method of holding the eccentrics is shown in Fig. 6 where H is a screw
passing through a slot in the straps into the eccentrics, and therefore locking the
same together.
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 I do not
generally claim the mode of construction of velocipedes claimed in the original first claim
but only when the slotted ends of the chain stays are formed in the manner described so
that weight and complication re avoided. What I claim is :
(1.) The pair of back stays of a velocipede hinged to the frame and carrying the
driving hub and chain wheel, and capable of being swung along the extremities of
the chain stays in the manner and for the purpose described.
(2.) The slotted ends of the chain stays formed in the manner described and in
combination with the hinged back stays.
(3.) The moveable chain wheel or bottom bracket of a velocipede furnished with
two eccentrics in the manner and for the purpose described.

page_text: (4.) The method of expanding an eccentric on a velocipede in the manner and
for the purpose described, and illustrated in Fig. 5.
(5.) The method of locking an eccentric on a velocipede, by means of the slotted
circular strap B in Fig. 6 substantially as described.
S
"
L 1001
PHILIP LOUIS RENOUF.