AN IMPROVED METHOD OF MOUNTING THE CRANKS OF VELOCIPEDES, SO THAT THE LENGTH OF STROKE MAY BE AUTOMATICALLY VARIED AT THE WILL OF THE RIDER to be as follows:
Year: 1884

page_text: I HENRY WILLIAM GODFREY of The Hythe Staines, in the County of Middlesex,
Engineer do hereby declare the nature of my said invention for "AN IMPROVED
METHOD OF MOUNTING THE CRANKS OF VELOCIPEDES, SO THAT THE LENGTH OF
STROKE MAY BE AUTOMATICALLY VARIED AT THE WILL OF THE RIDER
to be as
follows:-
"
Various attempts have been made to make the cranks of Velocipedes with variable
strokes, but I am not aware that cranks have been made so that the length of the
stroke may be automatically varied, and so that "back-pedaling" or driving the
machine backwards, may be effected without any extraneous movement on the part
of the rider. The object of my invention is to obtain this end; I construct my
cranks as follows;-On the end of the axle where the crank is usually keyed I fix
an eccentric, on the periphery of which are cut two, or more teeth, preferably of
a ratchet shape, according to the number of variations in the length of stroke
required. The crank is formed with a strap which fits over the eccentric, suitable
plates being screwed, or otherwise fixed, on each side of the strap to keep it in
place. A pawl is mounted on the crank to engage with the teeth on the eccentric
so that motion may be imparted to the axle when the crank is moved forward.
It will be seen that some means must be provided to lift the rising pedal & crank,
& also the rider's foot, as few riders are so expert as to have no back-pressure on
the rising pedal. To attain this end I make a frictional contact between the
eccentric & the crank as follows;-I make a recess in the outer face of the eccentric
& place in it a disc of leather, or any other suitable substance; on the plate
attached to the crank covering the eccentric I fix a flat spring which bears against
the leather disc & produces the frictional resistance. The spring being adjustable
so that the friction may be graduated as desired, & may be anything between what
is just sufficient to lift the rising pedal, & what is sufficient to "back-pedal " or to
drive the machine backwards on a smooth & level road.
In order that the rider may be able to "back-pedal" or to propel the machine
backwards at all times, I fit my cranks with an arrangement constructed as
follows;-On the inner face of the eccentric is fixed a smaller eccentric, whose
1

page_text: axes coincide with those of the larger one.
The plate on the inner side of the
crank is cut away in the centre to allow this small eccentric to revolve within it,
having a clearance of about one eighth of an inch. A tooth, preferably of a ratchet
shape, is cut on the inner edge of this plate in such a position that the tooth is at
right angles to the length of the crank, & when the crank is at the bottom of its
stroke the tooth is in front of the centre of the axle. Sliding in a slot cut through
the small eccentric on the centre line of it, & at right angles to the line of its
eccentricity, is what I call a gravitating bolt, which consists of a sliding piece with
a pawl shaped tooth cut at each end. This gravitating, bolt engages with the
tooth on the plate fixed to the crank & locks the eccentric to the crank, so that
back pressure may be exerted on the axle through the crank. As its name implies
this bolt acts by gravity & only operates when the crank is rising, so that if it is
desired to change the throw of the crank, the pedal must be held stationary by the
foot when the crank is at the bottom throw, for as the gravitating bolt does not
slide into gear with the tooth on the plate fixed to the crank, until the crank
begins to rise, the eccentric is then free to revolve independent of the crank, but
if it is not held stationary just at the bottom of the throw the gravitating bolt will
have engaged with the tooth on the plate fixed to the crank & locked it to the
eccentric fixed to the axlo; As this would be too sensitive in actual work I make
a little backlash between the tooth on the crank, & the teeth on the eccentric, so
as to allow more latitude in manipulating the crank to effect a change of stroke;
but I insure its perfect action by forming a projection on the plate attached to the
crank immediately opposite to the tooth, so that as the eccentric revolves indepen-
dent of the crank the projection catches the gravitating bolt, & forces it over,
almost into contact with the tooth opposite, so that the least gravitating movement
engages it with the tooth on the plate. before mentioned prevents the backlash
being felt by the rider.
It will be understood that each crank is constructed alike & that they are quite
independent of each other.
ROBT, ED. PHILLIPS,
Royal Courts Chambers,
70, 71 & 72 Chancery Lane, W.C.,
Agent for the Applicant.

page_text: I HENRY WILLIAM GODFREY of The Hythe Staines, in the county of Middlesex,
Engineer, do hereby declare the nature of my invention for "AN IMPROVED METHOD
OF MOUNTING THE CRANKS OF VELOCIPEDES, SO THAT THE LENGTH OF STROKE
MAY BE AUTOMATICALLY VARIED AT THE WILL OF THE RIDER," and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
Various attempts have been make to make the cranks of Velocipedes with
variable strokes, but I am not aware that cranks have been made so that the
length of the stroke may be automatically varied, and so that " 'back-pedaling" or
driving the machine backwards may be effected without any extraneous movement
on the part of the rider. The object of my invention is to attain this end ;. I con-
struct my cranks as follows:-On the end of the axle where the crank is usually
keyed I fix an eccentric on the periphery of which are cut two teeth, preferably of
a ratchet shape. The crank is formed with a strap which fits over the eccentric,
suitable plates being screwed, or otherwise fixed, on each side of the strap to keep
it in place. A pawl is mounted on the crank to engage with the teeth on the
eccentric so that motion may be imparted to the axle when the crank is moved
forward. It will be seen that some ineans must be provided to lift the rising pedal
and crank, and also the rider's foot as few riders are so expert as to have no back
pressure on the rising pedal. To attain this end I make a frictional contact between
the eccentric and the crank as follows:-I make a recess in tlie outer face of the
eccentric and place in it a disc of leather, or any other suitable substance; and fix
a flat spring which bears against the leather disc and the eccentric and produces
the frictional resistance; the spring being adjustable, so that the friction may be
graduated as desired, and may be anything between what is just sufficient to lift
the rising pedal, and what is sufficient to " back-pedal" or to drive the machine
backwards on a smooth and level road.
"
In order that the rider may be able to "back-pedal' or to propel the machine
backwards at all times, I fit my cranks with an arrangement constructed as
follows: On the inner face of the eccentric is fixed a smaller eccentric whose axes
coincide with those of the larger one. The plate on the inner side of the crank is
cut away in the centre to allow this sinall eccentric to revolve within it, having a
clearance of about one eighth of an inch. A tooth preferably of a ratchet shape is
cut on the inner edge of this plate in such a position that the tooth is at right
angles to the length of the crank, and when the crank is at the bottom of its stroke
the tooth is in front of the centre of the axle. Sliding in a slot cut through the
small eccentric on the centre line of it and at right angles to the line of its
eccentricity, is what I call a gravitating bolt, which consists of a sliding piece with
a pawl shaped tooth cut at each end. This gravitating bolt engages with the tooth

page_text: on the plate fixed to the crank and locks the eccentric to the crank, so that back
pressure may be exerted on the axle, through the crank. As its name implies this
bolt acts by gravity, and only operates when the crank is rising so that if it is
desired to change the throw of the crank, the pedal must be held stationary by the
foot when the crank is at the bottom throw, for as the gravitating bolt does not
slide into gear with the tooth on the plate fixed to the crank, until the crank
begins to rise; the eccentric is then free to revolve independent of the crank, but
if it is not held stationary just at the bottom of the throw the gravitating bolt will
have engaged with the tooth on the plate fixed to the crank and locked it to the
eccentric fixed to the axle; as this would be too sensitive in actual work I make
a little back lash between the tooth on the crank, and the teeth on the eccentric so
as to allow more latitude in manipulating the crank to effect a change of stroke,
but I ensure its perfect action by forming a projection on the plate attached to the
crank immediately opposite to the tooth, so that as the eccentric revolves inde-
pendent of the crank the projection catches the gravitating bolt and forces it over,
almost in contact with the tooth opposite, so that the least gravitating movement
engages it with the tooth on the plate. The frictional arrangement before
mentioned prevents the back lash being felt by the rider.
It will be understood that each crank is constructed alike, though the gravi-
tating bolt arrangement of one is just the reverse of the other as the cranks must
be made right and left handed.
In order that the construction of my cranks may be fully understood I will
describe them with the aid of the accompanying drawing which shows the left
hand crank, premising that the right hand one is constructed on exactly similar
lines with the gravitating bolt arrangement reversed.
In the accompanying drawing Fig 1 is an end elevation with the cover plate
removed. Fig 2 a side elevation partly in section of the crank complete with the
pedal fixed thereto. Fig 3 is an end elevation with the cover plate removed
showing the gravitating bolt. Figs. 4 and 5 are views of the cover plate, and
Figs. 6, and 7 views of one of the flange plates forming the eccentric strap. A is
the axle on to which is keyed the eccentric disc B. C is the crank with which is
formed the eccentric strap made up of two flanged plates c and c¹ screwed into the
strap of the crank. D is the pawl mounted on the crank C and engaging with the
teeth b. b. on the periphery of the eccentric disc. The flanged plate c forms a cover
for the outer side of the eccentric disc which is recessed to receive the friction
spring E bearing against the leather discs e. e. The strength of this friction spring
is adjusted by the screw e¹ which is threaded into the spring E and bears against
the eccentric disc B. On the inner face of the eccentric disc is formed a smaller
disc b¹ and the flanged disc c¹ is cut away to clear it, a thin plate F being provided
to cover the working parts. G is the gravitating bolt which engages with a
tooth cut or formed on the inner edge of the flanged disc c¹ opposite to this tooth
on the inner edge of the flanged disc c¹ is formed a projection y. which forces the
gravitating bolt Gover into contact with the tooth a when the axle is over running
the crank to alter the stroke, and so automatically locks the crank to the eccentric
for the purpose of back-pedaling.
I am aware that eccentrics have been used for some years for the purpose of
lengthening and shortening the throws of the cranks of Velocipedes, and therefore
I lay no claim to the use of the eccentric.
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. In a variable throw crank constructed by mounting the crank on an
eccentric, the use of the friction discs e, e, and spring e¹ as and for the purpose
hereinbefore described and shown.
Secondly. The gravitating bolt G constructed and arranged as and for the
purpose hereinbefore described and shown,

page_text: Thirdly. The combination of the eccentric B and crank strap C a known con-
trivance for the purpose of lengthening and shortening the throw of the cranks of
Velocipedes, and the gravitating bolt G a new contrivance for the purpose of
automatically locking the eccentric B to the crank strap C for the purpose herein-
5 before described and shown.
1885.
ROBT. ED. PHILLIPS, M.I.M.E.,
Consulting Engineer & Patent Agent,
Royal Courts Chambers,
70, 71 & 72, Chancery Lane, London, W.C.,
Agent for the Applicant.