Improvements in Cranks for Cycles, Motor Cars, and Engines.
Year: 1897

page_text: Date of Application, 23rd Mar., 1897
Complete Specification Left, 29th Sept., 1897-Accepted, 6th Nov.,
1897
PROVISIONAL SPECIFICATION.
Improvements in Cranks for Cycles, Motor Cars, and Engines.
We, AUGUSTUS CARDIGAN FREDRICH DANN, Gentleman, of 125, Talbot Road,
Southsea, Hants., and GEORGE THOMAS DANN, Gentleman, of 8 Cowper Road,
Acton, London W. do hereby declare the nature of this invention to be as
follows:
Our improved crank we make in the following manner. We have a fixed
eccentric round which we have an eccentric strap, and on this strap we have a
projection. On either side of the eccentric we have an arm V-d or grooved, this
arm revolving round one side of the fixed eccentric, and having a crank so made
that the crank arm is enabled to slide in and out. The projection on the strap
of the concentric is connected to the crank arm, so that when the crank is pushed
round the strap on the fixed eccentric lengthens the stroke at the most efficient
part of its travel and draws it in when its action is least needed.
Our improved crank can be applied to Cycles, Motor Cars, or Engines thereby
increasing the length and power of the stroke.
In the case of cycles the eccentric sheave may be fixed on the horizontal tube
of the lower bracket in the most suitable position for obtaining the greatest length
of stroke on the downward thrust of the riders leg, and the shortest length of stroke
on its upward travel, a spindle passing through the lower bracket tube with
ball bearings. Outside this spindle there would be the V-d or grooved arm, the
crank arm fitting into the V. or groove, so that by means of the eccentric strap
which travels round the fixed eccentric by the action of the projection it would
lengthen and shorten the stroke of the crank, whilst giving the same travel to
the pedal as if the stroke were uniform and yet increasing on its downward
motion and decreasing on its upward motion. The connection to the back wheel
can be worked by gearing, or by chain in the ordinary manner, placed in the
most suitable position.
In the case of Motor Cars or Engines, the crank on each end of the stroke can
he made according to the length of cylinder and at whatever point there is the
most power transmitted from the cylinder to the crank the leverage can he increased
by the method above described, the amount of leverage being controlled by the
amount of eccentric given to the fixed eccentric.
Doted this 93rd day of March 1897
Improvements in Cranks for Cycles, Motor Cars, and Engines.
We, AUGUSTUS CARDIGAN FREDERICK DANN, Gentleman, of 125, Talbot Road,
Southsea, Hants., and GEORGE THOMAS DANN, Gentleman, of 8 Cowper Road,
[Price 8d.]

page_text: Acton, London, W., 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 ;-
Our improved crank we make in the following manner. We have a fixed
eccentric round which we have an eccentric strap, and on this strap we have a
projection. On either side of the eccentric, we have an arm V-d or grooved, this
arm revolving round one side of the fixed eccentric and having, a crank so made
of the eccentric is connected to the crank arm so that when the crank is pushed
that the crank arm is enabled to slide in and out. The projection on the strap
round the strap on the fixed eccentric lengthens the stroke at the most, efficient
part of its travel and draws it in when its action is least needed.
Our improved crank can be applied to Cycles, Motor Cars, Engines or to all
mechanisms in which the power of the stroke is exerted on the outward thrust
or in one portion of the revolution, thereby increasing the length and power of the
stroke.
In the case of Cycles, the eccentric sheave may be fixed on the horizontal tube
of the lower bracket, in the most suitable position for obtaining the greatest
length of stroke on the downward thrust of the riders leg, and the shortest length
of stroke on the upward travel, a spindle passing through the lower bracket tube
with ball bearings. Outside this spindle there would be the V-d or grooved arm,
the crank arm fitting into the Vor groove, so that by means of the eccentric
strap which travels round the fixed eccentric; by the action of the projection, it
would lengthen and shorten the stroke of the crank, whilst giving the same travel
to the pedal as if the stroke were uniform; and yet increasing on its downward
motion and decreasing on its upward motion The connection to the back wheel
can be worked by gearing, or by chain in the ordinary manner, placed in the most
suitable position.
In the case of Motor Cars or Engines, the crank on each end of the stroke can
be made according to the length of cylinder, and at whatever point there is
the most power transmitted from the cylinder to the crank the leverage can be
increased by the method above described, the amount of leverage being controlled
by the amount of eccentric given to the fixed eccentric.
In our improved crank we obtain a greater leverage at the most efficient part
of the stroke, and yet maintain a uniform velocity throughout the revolutions.
In order that our Invention may be the better understood, we hereunder
proceed to describe same in connection with the drawings annexed hereto
These drawings show our improved crank as applied to Cycles, anu modifications
thereof adaptable to other mechanisms will readily suggest themselves to those
skilled in the art. In the drawings like letters apply to like parts.
Fig. 1 shows an end view, Fig. 2 shows a plan partly in section, Fig. 3 shows
an inside view of Fig. 2, and Fig. 4 'shows a plan section through the eccentric.
We have a fixed eccentric A. on each side of the horizontal tube of the lower
bracket B., round which we have a strap C. made in two pieces, one to screw into
the other for adjusting the ball races on which the strap C revolves.round the
eccentric A., a stud D. projecting at right angles from said strap C. to make
connection with slide block' E., as hereinafter described, the stud D. passing
between the inner periphery and axle of the wheel actuated. Through the lower
bracket B. is fitted a spindle or axle F. to carry the chain wheel G. on one end
and the disc H. on the other end. The chain wheel G. is fitted with adjustable
guides I. diametrically across the face, with ball races J. The slide block E. is
made with corresponding ball races in both. edges, blocked at both ends and in
the centre to retain the balls in their proper positions. In the centre of said
side block E. is a projection K. for keying on the crank arm L. At one end of
said slide block E. is a hole M. (fitted if required with balls) to receive and to form
bearing of the projection, D. of strap C. of eccentric A. The disc H. fixed on the
opposite end of the axle F. passing through the bottom bracket B. is similarly
fitted with adjustable guides and slide block to carry the crank at that end, with

page_text: hole treceive connecting stud of opposite eccentric strap. By this means the
pedals, fixed in the usual manner to the outer ends of crank arms are drawn
towards and from the centre of the chain wheel without causing the slightest
variation of velocity, at the same time describing a perfect circle concentric to the
centre of the eccentric sheave, the slide blocks working in the guides diametrically
to the chain wheel on the one side and to the dise on the other. In this way the
ordinary bicycle can be furnished with our improved crank utilising the existing
pedals and cranks.
The whole of the mechanism may be cased in, and made practically dust proof,
by means of a cap plate fitted over slide blocks secured with and by the bolts of
adjustable guides, and the eccentrics and straps may be cased in with revolving
covers.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed, we declare that what
we claim is :-
1. The improved crank for the transmission of power, substantially as described
and shown in drawings.
2. In a crank for the transmission of power, the combination of a fixed
eccentric with a strap working on its outer circumference, said strap having a
right angle pin, this pin passing between the inner periphery and axle of the wheel
actuated, and being connected to and revolving with the crank, thereby lengthen-
ing and shortening the throw of the crank, the outer or larger crank revolving
concentrically to the centre of the eccentric sheave, at the same time revolving at
a uniform velocity as though the crank were uniform throughout the revolution,
the strap round the eccentric perfectly compensating and preventing any
variation of velocity.
E. E. WIGZELL,
Agent for Applicants.