IMPROVEMENTS IN MACHINERY FOR PROPELLING VELOCIPEDES AD ATHED הם זחת...
Year: 1883

page_text: LETTERS PATENT to John Theodore Sibree and Thomas Foster Stenson
Mechanical Engineers both of Handsworth in the County of Stafford for an
Invention of "IMPROVEMENTS IN MACHINERY FOR PROPELLING VELOCIPEDES
AD ATHED
הם זחת...
"
PROVISIONAL SPECIFICATION left by the said John Theodore Sibree and
Thomas Foster Stenson at the Office of the Commissioners of Patents on the
10th October 1883.
JOHN THEODORE SIBREE and THOMAS FOSTER STENSON Mechanical Engineers,
both of Handsworth in the County of Stafford, "IMPROVEMENTS IN MACHINERY
FOR PROPELLING VELOCIPEDES OR OTHER WHEELED CARRIAGES"
Our Invention consists of the improvements hereinafter described, in that
portion of the machinery of Velocipedes whereby the muscular power of the rider
is communicated either to cranks or to other expedients or mechanical equivalents
for converting reciprocating into circular motion.
The objects of our Invention are to enable the rider of a velocipede, or other
wheeled carriage, to increase or diminish the purchase or leverage on the driving
wheels at pleasure, so as to accomodate the force exerted on the wheels to the
varying resistances, due to gradients, opposing head wind, or state of the road, and
to enable the rider to change the length of stroke of the treadles without descending
from the saddle or seat to alter the radius of the crank. Also to admit of the
effective working position of the feet to be varied with the view of relieving
tired and overworked muscles and of allowing others to be called into action.
In carrying our invention into effect we arrange levers, to which treadles are
attached, in such a manner that the fulcrum on which the lever bears shall change
its position automatically with reference to the driving point, and the driven point
of the lever, nearly in accordance with the requirements of the case, so that the
pressure exerted by the feet shall be communicated to the wheel or wheels with a
force varying in intensity with the resistance to be overcome, and also varying in
intensity and duration at the will of the rider, We employ a lever for each foot

page_text: of the rider to one end of which is attached the treadle. At some convenient
point in the lever a connecting rod, chain or other link (hereafter called the
connecting rod) is hinged, and the connecting rod communicates the angular motion
of the lever, either wholly or in part to the crank pin or other connection with
the hub of the wheel. A portion of the lever bears upon a fulcruin, which however
is not a fixed point but serves as an abutment varying in its distance from the
other points to which force is communicated or taken off. This fulcrum or
abutment consists of a curved bar constantly under the influence of a spring
which tends to turn the said cam into the position most favourable for a stroke
under moderate pressure; that is, in such a position as to place the acting surface
of the cam or fulcrum at its greatest distance from the connecting rod. But should
the rider find it necessary to exert a greater force on the wheel than the length
of lever thus given would permit him to do, a slight extra pressure on the treadle
causes the cam or curved bar to partially revolve on its own fixed stud and present
another part of its surface, nearer to the attachment of the connecting rod, to act
as a fulcrum for the lever. The distance between the fulcrum and connecting rod
being thus diminished the relative proportions of the lever are altered and a
greater purchase on the crank is thus obtained.
The variable abutment or fulcrum does not always consist of a cam or curved bar
as above described, but we sometimes prefer a flat steel spring one end of which is
firmly fixed in the frame-work of the vehicle and the other end hinged to the lever
to serve as an occasional fulcrum. When the pressure of the foot is applied to the
treadle, the spring is caused to deflect, taking the form of a curve, and more or less of
this curve is pressed upon by the lever, so that the effective fulcrum may be situated
at either of the extreme ends of the spring, or at any intermediate point in its length.
Or, instead of hinging the lever on the end of a flat spring, we sometimes prefer to
binge the said lever on the end of a bar or secondary lever which is under the
influence of a spiral spring constantly tending to deflect the end of the bar to which
the lever is attached the said bar being free to turn on its own fixed stud being
partially under the influence of the spring, and partially under the opposing
influence of the lever. By sliding the said bar through a socket arranged to clip
it, its effective length may be varied and the end which serves as a fulcrum may be
brought more or less near to the point at which the spring acts, and consequently
more or less under its influence. To adjust this bar the rider would simply
dismount, and adapt it to meet his requirements according to the resistances
anticipated, but the arrangement has still this peculiarity, that in case of a sudden
emergency, extra pressure on the treadle will cause the bar to deflect to such an
extent as to allow the lever to bear on a fixed fulcrum, which being near to the
connecting rod affords a greater purchase. The crank and connecting rod may be
dispensed with, and a ratchet wheel with a pawl, silent feed, or their equivalent
attached to the axle and driven by a band acting in connection with a drum on
which it is partially coiled and securely anchored. To cause the drum and lever
to make a return stroke, raising the treadle and assisting the foot in its upward
movement, the said drum, is provided with a spiral spring, one end of this spiral
spring (in some cases) may be attached to a suitable cam and the other end to the
drum, so that the cam is the anchorage, (as it were) for the spring. The cam in
its turn is also anchored or held on its curved surface by a steel or other band to
a second cam which is rigidly secured to the cam or curved bar, forming the
varying fulcrum previously described. The cam becoming influenced by the
spiral spring connected to the drum, an additional spring is unnecessary and may
be dispensed with. The curved faces of the two cams may be of such a form as
may be found most advantageous and need not be arc's of a circle. A crank
and connecting rod may be adapted instead of the ratchet wheel and pawl.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Theodore Sibree and Thomas Foster Stenson in the Patent
Office on the 10th April 1884.
"
JOHN THEODORE SIBREE and THOMAS FOSTER STENSON Mechanical Engineers,
both of Handsworth in the County of Stafford IMPROVEMENTS IN MACHINERY
FOR PROPELLING VELOCIPEDES OR OTHER WHEELED CARRIAGES"
Our Invention consists of the improvements hereinafter described, in that
portion of the machinery of Velocipedes whereby the muscular power of the rider
is communicated either to cranks or to other expedients or mechanical equivalents
for converting reciprocating into circular motion.
The objects of our Invention are to enable the rider of a Velocipede, or other
wheeled carriage, to increase or diminish the purchase or leverage on the driving
wheels at pleasure, so as to accomodate the force exerted on the wheels to the
varying resistances, due to gradients, opposing head wind, or state of the road, and
to enable the rider to change the length of stroke of the treadles without descending
from the saddle or seat to alter the radius of the crank. Also to admit of the
effective working position of the feet to be varied with the view of relieving tired
and overworked muscles and of allowing others to be called into action.
In carrying our Invention into effect, we arrange levers, to which treadles are
attached, in such a manner that the fulcrum on which the lever bears shall change
its position automatically with reference to the driving point, and the driven point
of the lever, nearly in accordance with the requirements of the case, so that the
pressure exerted by the feet shall be communicated to the wheel or wheels with a
force varyit g in intensity with the resistance to be overcome, and also varying in
intensity and duration at the will of the rider.
We employ a lever for each foot of the rider to one end of which is attached the
treadle. At some convenient point in the lever a connecting rod, chain or other
link (hereafter called the connecting rod) is hinged, and the connecting rod
communicates the angular motion of the lever, either wholly or in part to the
crank pin or other connection with the hub of the wheel. A portion of the lever
bears upon a fulcrum, which however is not a fixed point but serves as an abutment
varying in its distance from the other points to which force is communicated or
taken off. This fulcrum or abutment consists of a curved bar constantly under
the influence of a spring, which tends to turn the said cam into the position most
favourable for a stroke under moderate pressure; that is, in such a position as to
place the acting surface of the cam or fulcrum at its greatest distance from the
connecting rod.
But should the rider find it necessary to exert a greater force on the wheel than
the length of the lever thus given would permit him to do, a slight extra pressure
on the treadle causes the cam or curved bar to partially revolve on its own fixed
stud and present another part of its surface, nearer to the attachment of the
connecting rod to act as a fulcrum for the lever. The distance between the
fulcrum and connecting rod being thus diminished the relative proportions of
the lever are altered and a greater purchase on the crank is thus obtained.
The variable abutment or fulcrum does not always consist of a cam or curved bar
as above described, but we sometimes prefer a flat steel spring, one end of which is
firmly fixed in the frame-work of the vehicle, and the other end hinged to the
lever to serve as an occasional fulcrum. When the pressure of the foot is applied
to the treadle, the spring is caused to deflect, taking the form of a curve, and
more or less of this curve is pressed upon by the lever, so that the effective fulcrum
may be situated at either of the extreme ends of the spring, or at any intermediate

page_text: carried by a drum marked c, which has a vibratory revolving motion communicated
to it by means of a flexible band or cord attached to the lever b, at one end, and
anchored at the other end to the periphery of the said drum c, The drum c, is
further provided with a spiral spring d, one end of which spring is fastened to its
periphery at the side, and the other end to the cam e, not previously mentioned.
The cam e, as well as the drum c, are free to revolve or oscillate on a stud or bush,
which is concentric with the axle. The cam e, is prevented to some extent from
revolving by means of a flexible band, which has one end attached to the periphery
of the cam e, and the other end to the periphery of the cam f, which in its turn is
checked in revolving by being firmly attached to a bar which we prefer to call a
secondary lever g, The secondary lever g, can vibrate to a certain extent on its
stud h, when pressed upwards by the main lever b, an effect which will occur when
extra pressure is put upon the treadle by the foot of the rider-The spiral spring d,
has two functions, one is to cause the drum to assume its original position after a
down stroke of the treadle, and the other is to press down the secondary lever g,
by the intervention of the two cams and the flexible band before mentioned. To
cause each lever to make its upward stroke at the same time that the opposite lever
is making its downward stroke a band connected to each lever and passing over an
additional drum or pulley may be employed-The two cams e, and ƒ may have
their peripheries struck either to the arc of a circle or to an irregular curve as may
be found convenient--The irregular curves would have the effect of increasing or
diminishing the power of the spiral spring over the secondary lever g, should this
be found necessary.
The real fulcrum on which the main lever acts may thus be the extreme end of
the secondary lever g, under ordinary circumstances, or the real fulcrum may be
the stud h, on which the secondary lever partially revolves-That is; if the
secondary lever g, is pressed upwards so as to allow the end of the main lever b,
to rise far enough, a certain part of the length of lever b, marked k, will of
necessity touch the stud h, which then becomes the real fulcrum and from the
nearness of its position to the work gives the treadle a greatly increased leverage
or purchase over the drum c, which being communicated to the axle by the means
already described enables the rider to overcome a suddenly encountered difficulty
-The secondary lever g, can be adjusted in length by being moved through the
socket, and fastened by a set screw. Fig. 5. represents a side elevation of a
portion of a tricycle. Fig. 6. a plan-Fig, 7, an end view and Fig 8, an enlarged
detail of a portion of the driving gear. Referring to Fig, 8. The spiral spring a,
acting upon the lever b, exerts a force through the link c, on the lever d, of which
the member previously called the secondary lever in the former modification forms
a part The position of the acting fulcrum e, is thus partly under the influence of
the spiral spring a, and partly under the influence of the pressure on the main
lever communicated by the foot of the rider-The result is the same as that
previously described-Connecting rods are shown in Fig. 5. but sometimes we prefer
to use the ratchet wheels and pawls or their equivalent to communicate the motion
to the axle. The small lever b, is introduced to modify the action of the spring ou
the lever d, When extra pressure is imposed upon the main lever f the upper
member of the lever d, is forced to the right which causes the link c, to pull the
arm o, of the lever b, round to the right also-The effect of this would be to
elongate the spring and increase its reacting force were it not for the fact that the
short arm p, of the lever b, is moved round into such a position as to diminish its
effective leverage or purchase-At the same time the arm o, being moved to the
right increases its effective leverage, inasmuch as its centre line under such
circumstances more nearly approximates to, if it does not reach an angle of 90°
with the direction of pull-Should the rider wish to lock the lever d in a fixed
position so that the fulcrum should not vary, provision has been made to enable
him to do so
The handle g by means of the vertical shaft h, turns the screw i, which causes
the lever J to oscillate on a fixed stud k-The effect of this is to tighten the

page_text: spring a, or at the same time if the lever is caused to oscillate far enough to raise
the rod 1, sufficiently high to cause the spring catch m, to gear into the notch of
the sector n, and lock the lever d, in the desired position.
Figs 3 and 4 represent a modification of the usual internal ratchet wheel and
pawl, the object of which is to cause the pawl to engage with the teeth of the
ratchet as quickly as possible-This object is effected by causing the pawl to travel
in its circular path with a greater angular velocity than would be obtained by
pivotting it directly to the driver on which the band is coiled-This additional
velocity is obtained by the use of multiplying levers XX; one end of each of
the said levers working in the loosely revolving block Y the said block being
independant of the axle, but revolving on a seperate stud concentric with it.
Having thus described the nature of our Invention and the manner in which
the same is to be performed, and some modifications of the same, we wish it to be
particularly understood, that We do not limit ourselves to the precise details herein
described and illustrated as the same may be slightly varied and diversified
without departing from the nature and spirit of our invention; but what we do
claim and wish to protect under these our Letters Patent as of our invention are
the Improvements in Machinery for propelling Velocipedes or other wheeled
carriages the several arrangements or combination of parts, substantially as herein
before described and illustrated in the accompanying Drawings, by means of which
through the Automatic or manipulated variation in the position of the fulcrum on
which a lever turns the effective force communicated to the driving wheels of a
carriage shall be varied in approximate accordance with the resistance to be
overcome.
'
In witness whereof we the said John Theodore Sibree and Thomas Foster
Stenson have hereunto set our hands and seals this eighth day of April, in the
year of our Lord, One thousand eight hundred and eighty four.
Witness,
ALFRED PERRY C.E.
Handsworth
Birmingham
חז'
THE DORE DIDREM
(AST)
THOMAS FOSTER STENSON (L.S.)