Year: 1894

page_text: Date of Application, 29th Nov., 1894
Complete Specification Left, 29th Aug., 1895-Accepted, 12th Oct., 1895
I PETER FRODSHAM of 12 Brighton Road, Birkdale, Southport, in the County
of Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
My said invention relates to improvements in bicycles, tricycles and other
wheeled vehicles driven by manual power. The invention relates more particularly
to the cranks and treadles of such vehicles and consists of improved means whereby
the throw of the cranks is practically increased and lessened during revolution, so
as to enable the pressure of the foot to be applied to the treadles in the most
convenient, effective, and economical manner possible. The advantage of a long
crank is that the leverage is thereby increased, while the disadvantage is that such
long cranks can only be conveniently used by a limited number of riders.
To
On the other hand the disadvantage of a short crank is that the leverage is
decreased and the driving rendered more difficult. By means of my improvements
I am enabled to combine the advantages of the long crank with the conveniences
of the short crank and without the disadvantages of either. Stated shortly I
obtain the desired effect by the use of mechanism which will move the treadle of
the crank outward so as to present a longer throw to the most effective period of
pressure of the riders' foot, while the same mechanism decreases the length of the
throw when the crank is at or near the foot of the stroke and on the up-stroke,
that is to say, during the idle or comparatively idle portion of the stroke.
obtain this iuward and outward motion of the ticadle 1 form the outer end of the
crank with a slot which is occupied by the usual extension of the treadle stud.
Upon the end of the treadle I form an excentric disc which is the medium whereby
the treadle is moved to and fro in the slot. A simple mode of arranging this disc
so as to perform its duties would be to confine it between ledges cast or formed on
the crank at each end of the slot, the effect of the revolution of the crank upon the
excentric being that the axis of the treadle is thereby moved to and fro in the slot.
To steady this motion I connect the sliding extension of the treadle slot to a fixed
radial point on the crank by means of a link.
The neck of the stud which occupies the slot may carry an antifrictional sleeve
or it might consist of a block sliding in the slot. The connecting link or the fixed
centre might be slotted so as to allow the stud neck to hear upon either side of the
slot. Instead however of confining the excentric disc between ledges as described
I prefer to enclose the excentric in a ring or strap connected by a link to the
crank arm or to the chain or driving wheel axis. This makes the action of the
excentric much more smooth and regular and in addition, provision can easily be
made for taking up wear. Ball bearings might be used to diminish friction
between the excentric and the strap or ring. The effect of either arrangement is
that when the excentrics have been properly set relatively to the treadles, the
treadle of each crank is moved to the outer end of the slot in the crank when
the crank is lying forward and in the best position for receiving the most
effective pressure of the riders' foot, the throw being thus practically increased
at this point, while towards the foot of the stroke and on the up stroke behind
the centre the treadle is moved inward, and the throw thus diminished at these
points in the revolution. It is not essential that the excentric disc should be
mounted at the treadle end of the cranks. The excentrics might be supported

page_text: from the frame of the machine, and so as to surround the crank shaft, the
sliding or vibrating neck of the treadle stud being connected by a link or rod
to the strap or ing of the said fixed excentric.
In this case the strap on ring is carried round by the crank, and as the
excentric is set towards the front of the stroke it follows that as the crank
revolves the treadle is moved at the proper interval towards and away from
the centre of the crank shaft and the same result obtained as in the foregoing
instances. This arrangement does not, ințerfera in any respect with the driving
chain or chain wheel. I might also utilise my invention in combination with
side walking levers the treadles or their equivalents being carried by the outer
ends of the said side levers, while the rear ends of the lever are connected to
dependent links from a tail projecting over the rear driving wheel.
The action
of the excentrics as hereinbefore described tends to magnify the forward and
working portion of the throw and to diminish the throw at the less favourable
portions of the path or cycle of the treadles.
Apart however from these and other possible modifications, the gist of my
invention consists in the employment of a crank constructed in the indicated or, in
an equivalent manner so as to increase the leverage at the most favourable portion
of the throw and diminish the throw at the less favourable points as. described.
Dated this 28th day of November 1894.
E. K. DUTTON & Co.,
5 John Dalton Street, Manchester, Agents.
Improvements in Velocipedes.
I PETER FRODSHAM of 12 Brighton Road, Birkdale, Southport, in the County
of Lancaster, 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 and accompanying,drawings
My said invention relates to improvements in bicycles tricycles and other wheeled
vehicles driven by manual power. The invention relates more particularly to the
cranks and treadles of such vehicles and consists of improved means whereby the
throw of the cranks is practically increased and lessened during revolution, so as to
enable the pressure of the foot to be applied to the treadles in the most convenient,
effective, and economical manner possible. The advantage of a long crank is that
the leverage is thereby increased, while the disadvantage is that such long cranks
can only be conveniently used by a limited number of riders. On the other hand
the disadvantage of a short crank is that the leverage is decreased and the driving
rendered more difficult. By means of my improvements I am enabled to combine
the advantages of the long crank with the conveniences of the short crank and
without the disadvantages of either.
To render my invention properly understood I will now proceed to describe
the same more fully, reference being had to the annexed four sheets of
drawings.
On Sheet 1-
Fig. 1 is a side elevation of one modification of my improved velocipede crank
and treadle, the treadle being shown in the position when nearest to the centre of
the crank axle vz. at short stroke.
Fig. 2 is a similar view with the treadle removed to show the excentric and
links.
Fig. 2 shows the excentric turned round so as to bring the treadle further from
the axle centre, viz, to loug stroke.
Fig. 3 is a plan of Figs. 1 and 2.

page_text: Fig. 4 is a view of the side of the crank opposite to the side shown in Figs. i
and 2 but with the treadle shown at long stroke.
The crank A which is secured in the ordinary manner upon the crank axle is
formed at the outer end with a curved slot A¹ and a projection A. On one side
of this slotted portion of the crank I form shoulders A3 A3 and between the
shoulders I place a disc B, which disc carries the treadle stud C the said stud
being excentrically disposed upon the disc.
The stud C extends through an
antifriction bowl & which occupies the curved slot A¹ and terminates in a screw
and nut C which binds it to the outer pivotted link F.
Upon the stud C I attach the usual side pieces D D and rubber treads E E¹ the
stud of the tread E' entering the disc B and being secured thereto.
Side links F F are centred upon the projection A2 and also upon the excentrically
disposed stud C. The consequences of this arrangement will be evident.
If the
foot is placed upon the treadle and the crank made to revolve upon its axis, the
disc B is held stationary between the shoulders A³ A and as the crank alters
its position the position of the stud C becomes altered relatively to the crank, that
is to say as the crank revolves the stud C moves from one end of the slot A¹ to
the other end. Thus when lying in its forward position the distance of the pedal
stud C from the centre of the crank axle is greatest and therefore the crank offers
the longest leverage. On the other hand when at the bottom of the stroke and
when lying towards the back of the machine, the stroke of the crank is shorter.
The links F F¹ steady and guide the treadle in its vibrating curved path, but the
said links F F might be dispensed with. The distance by which the stroke of the
crank is alternately lengthened and shortened is indicated in Fig. 2. The con-
necting links F, F¹ might be slotted so as to allow the anti-friction bowl G to bear
against either side of the curved slot; or the fixed centre in the projection A³
might be so slotted.
On Sheet 2-
Fig. 5 is a side elevation and Fig. 6 a sectional plan of a modification of my
invention.
In this case instead of confining the excentric disc B between shoulders on the
crank as in the foregoing figures I surround the disc B by a ring or strap H applied
as shown in two halves, H H+ and held together by the bolts H. One of the
excentric strap halves H has a tail or link H pivotted at H³ to the crank arm A.
The slot A in the head of the crank is made straight and receives an anti-friction
bowl G which is mounted upon the collared carrier I which receives the stud C of
the treadle. This carrier I screws into the excentric disc B binding and holding
the side piece D as clearly appears in the drawing. I prefer to have ball bearings
between the strap H and the excentric B so as to diminish friction. I also have
ball bearings at the pivot connection H³ of the link H with the crank arm.
A guide piece J bolted to the outer excentric-strap half H+ slides on a way formed
on the free end of the crank arm, and thus steadies the vibrating movements of the
disc and excentric straps. A thin plate K is applied to the opposite side of the
slot so as to exclude dust and weather. When this modified form of crank is being
operated, the foot holds the pedal and disc B in one unchanged position and owing
to the revolution of the crank the stud C is on the outstroke furthest from the
crank axle centre and therefore in the most favourable position for leverage, while
in the lower upper and rearward positions the stud C is nearest to the crank axle
centre thus producing the desired effect.
On Sheet 3-
Fig. 7 is a side view of a further modification of my invention.
Fig. 8 is a sectional plan.
Fig. 9 is a view of the crank arm alone.
Fig. 10 shows one of the side pieces of the treadle.
The construction of this modification presents some features similar to those
illustrated in Sheet 2.
In the present instance however the stud C of the treadle is screwed into the

page_text: centre of the dise B and an excentrically disposed stud L projecting from the disc
carries an anti-friction roller which occupies the slot A' of the crank A. The
dise B works in ball bearings in a cup luk H pivotted at H³ to the crank A.
The disc B thus works excentrically upon the stud L although without changing
its distance from the crank axle centie. To get the increased throw the rider at
the forward stroke presses with his toes upon the forward tread E of the pedal and
front portion of the wire frame T thereby greatly extending the leverage of the
crank arm.
The guide piece J for steadying the vibrations of the link H is made
of a jaw formation as shown at Fig. 8 the wear being thus at both sides of a
renewable part.
By making the studs which cairy the treads E E¹ with prolonged screw
extensions and jamb nuts as shown, the distance between the side pieces D D¹ cau
be altered and adjusted the wire clips M springing either way.
The inner side piece D' is formed with a boss which runs in ball bearings in the
outer side of the cup link H. The side D¹ is thus confined between the collar (2
on the stud C and the link H. If wear should take place it can be taken up by
removing a little of the packing N. The outer side of the slot A' is closed by a
steel plate K as in the former instances.
On Sheet 4-
Fig. 11 is a plan view of an arrangement in which the excentric discs B
instead of being carried by or connected to the treadle are fixed to the frame of a
bicycle. In the drawing the boss through which the crank axle passes is marked O.
The members P P extend towards the bearing of the rear wheel. The member Q
extends up towards the saddle. The member R extends towards the steering post.
The excentric discs B are carried by side plates B₁ which are bolted to the
Thus the
members P, P and to the ends of a stay S clamped to the member R.
discs Bare fixed and immovable. Upon the excentric discs B I mount excentric
straps H H connected by an extension H2 with a sliding carriage T' mounted on
the end of the crank A and carrying the stud C which supports the treadle. The
neck of the stud C is furnished with an anti-triction bowl which rolls in the slot A¹
of the crank arm. Thus it will be seen that as the cranks revolve, the herein before
described excentric disposition of parts will cause the treadles to be at their
furthest distance from the centre of the crank axle, when extended on the forward
stroke, and at then nearest approximation to the crank axle centre when pointing
to the rear.
Having now particularly described and ascertained the nature of my said inven-
tion and in what mannei the same is to be performed I declare that what I
claim is :-
1. The improved cranks and treadles for obtaining greater leverage at the most
favourable part of the stroke, substantially as described and as illustrated.
2. As means for imparting motion to velocipedes the improved cranks in which
the treadle is moved further from the crank axle centre so as to present increased
leverage to the foot of the rider at the most favourable part of the stroke while
the said treadle is moved nearer to the crank axle centie so as to diminish the
stretch at other and less favourable portions of the stroke, substantially as described
and as shown.
3. A velocipede crank in which the treadle is furnished with an excentric disc
working between shoulders formed on the crank and either with or without
connecting vibrating-links for the purpose and substantially as described and as
illustrated on Sheet 1 of the drawings.
4. The improved velocipede crank in which the treadle is secured to an excentric
disc, the said disc being surrounded by a ring or excentric strap connected by a
link or extension with a pivot on the crank arm, for the purpose and substantially
as described and shown in Sheet 2 of the drawings.
5. The improved velocipede crank substantially as described and as illustrated
in Sheet 3 of the drawings.

page_text: 6. The improved velocipede crank in which the treadle is mounted on a carriage
or part sliding on the crank arm and operated to and fro by au excentric strap and
link working on a disc fixed on the frame of the machine excentrically with relation
to the crank axle, for the purpose and substantially as described and illustrated in
Sheet 4.
Dated the 28th day of August 1895
E. K. DUTTON & Co.,
Chartered Patent Agents, 5 John Dalton Street, Manchester,
For the Applicant.