Improvements in Unicycles.
Year: 1895

page_text: COME DETE
Improvements in Unicycles.
I, FABIAN HARRISON ARMISTEAD, corner 2nd and Bridge Streets, of Farm-
ville, in the County of Prince Edward, and State of Virginia, United States of
America, Farmer, 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, reference being had to the accompanying
drawings, and to letters of reference marked thereon, which form a part of this
Specification
:―
My invention relates to a unicycle, and has for its object to provide a simplified
and improved construction for increasing the stability of the equilibrium of the
rider and for communicating the motion of the crank-shaft to the rim with the least
amount of resistance.
Further objects and advantages of the invention will appear in the following
description, and the novel features thereof will be particularly pointed out in the
appended claims.
In the drawings
Fig. 1, is a side view of a unicycle embodying my invention.
Fig. 2, is a side view, partly broken away.
Fig. 3. is a horizontal section, showing the operating mechanism in plan.
Fig. 4, is a rear view of the framework detached.
Fig. 5, is a detail view of the rock-shaft, by which the brake-bar is journaled.
Fig. 6, is a detail view of the lower end of the brake-bar, showing the frictional
surfaces.
Similar numerals of reference indicate corresponding parts in all the figures of
the drawings.
1, designates the rim, which is provided with the interior V-shaped track 2, and
3, represents the central spindle concentric with the rim and divided to form
opposite aligned parts 4-4, which are held in place by means of the spokes 5.
These spokes are preferably bifurcated or forked at their outer ends, to prevent
lateral vibration and stiffen the structure.
The bearing-frame comprises a yoke 6, having parallel arms 7, provided at their
upper ends with bearings for the reception of the parts or members of the spindle,
and these arms of the yoke are preferably extensible, the upper portions 8, thereof,
being connected to the lower or main portions of the arms by means of a slot and
pin connection, in which the slot is shown at 9, and the pin at 10. The frame
proper, exclusive of said yoke, is approximately triangular in shape, having a
substantially vertical side 11, consisting of parallel plates 12, which are extended
below the point of connection therewith of the approximately horizontal side 13,
to form the arms 14, between which is rotatably mounted the guide wheel 15.
16, represents the driving-wheel, which is carried by a shaft 17, mounted in
bearings at the front end of the bearing frame at the junction of the front and
lower sides thereof, and upon the shaft of this driving-wheel, is fixed a chair.-
wheel 18, connected by means of a chain 19, with an enlarged chain-wheel 20,
which is fixed to the crank-shaft 21. This crank-shaft is provided at its ends
with pedal cranks 22, and at a point between the opposite parallel plates forming
the frame with a small chain-wheel 23, which is connected by means of a similar
chain-wheel 24, fixed to a countershaft 25. This countershaft is mounted in
bearings in a rearwardly extending supplemental frame 26, and is provided at its
extremities with chain-wheels 27, which are connected by means of chains 28, with
chain-wheels 29, fixed to the spindle of the rim.
Fig. 4, is a rear view of the framework detached.
Fig. 5, is a detail view of the rock-shaft, by which the brake-bar is journaled.
Fig. 6, is a detail view of the lower end of the brake-bar, showing the frictional
surfaces.
Similar numerals of reference indicate corresponding parts in all the figures of
the drawings.
1, designates the rim, which is provided with the interior V-shaped track 2, and
3, represents the central spindle concentric with the rim and divided to form
opposite aligned parts 4-4, which are held in place by means of the spokes 5.
These spokes are preferably bifurcated or forked at their outer ends, to prevent
lateral vibration and stiffen the structure.
The bearing-frame comprises a yoke 6, having parallel arms 7, provided at their
upper ends with bearings for the reception of the parts or members of the spindle,
and these arms of the yoke are preferably extensible, the upper portions 8, thereof,
being connected to the lower or main portions of the arms by means of a slot and
pin connection, in which the slot is shown at 9, and the pin at 10. The frame
proper, exclusive of said yoke, is approximately triangular in shape, having a
substantially vertical side 11, consisting of parallel plates 12, which are extended
below the point of connection therewith of the approximately horizontal side 13,
to form the arms 14, between which rotatably mounted the guide wheel 15.
16, represents the driving-wheel, which is carried by a shaft 17, mounted in
bearings at the front end of the bearing frame at the junction of the front and
lower sides thereof, and upon the shaft of this driving-wheel, is fixed a chair.-
wheel 18, connected by means of a chain 19, with an enlarged chain-wheel 20,
which is fixed to the crank-shaft 21. This crank-shaft is provided at its ends
with pedal cranks 22, and at a point between the opposite parallel plates forming
the frame with a small chain-wheel 23, which is connected by means of a similar
chain-wheel 24, fixed to a countershaft 25. This countershaft is mounted in
bearings in a rearwardly extending supplemental frame 26, and is provided at its
extremities with chain-wheels 27, which are connected by means of chains 28, with
chain-wheels 29, fixed to the spindle of the rim.

page_text: From the above description, it will be seen that when the crank-shaft is rotated,
motion is communicated through the intermediate sprocket wheels and chains to
the shaft of the driving-wheel, thus causing the latter to ride upward upon the
rim and thereby change the center of gravity and throw it in advance of the
spindle of the rim and at the same time said rotation of the crank-shaft is
communicated by means of the intermediate connecting chains and wheels with the
spindle of the rim to assist in driving the machine forward. The seat for the
rider is arranged between the arms of the yoke forming a part of the bearing-
frame, whereby when the rider is in position, the center of gravity of the entire
structure, including the rider, is below the axis of the rim.
The means for braking and guiding or steering the device, consists of a brake-
shoe 30, having a bearing-surface 31, to engage the inner edge of the V-shaped
track or guide, and having lateral bearing surfaces 32, to engage the sides of said
track or guide, the interval between said bearing-surfaces being greater than the
width of the track or guide, whereby either of the lateral bearing surfaces, but not
both, may be brought into contact. This shoe is carried by the stem 33, which is
supported upon the framework at a suitable point by means of a universal joint 34,
and is provided at its upper end with a handle-bar 35. This universal joint may
be of any preferred construction, but a simple arrangement is by means of a
transverse bar 36, swiveled at its extremities in the side plates of the frame and
provided with a longitudinal slot 37, through which passes and in which is
fulcrumed the stem, whereby the stem is capable of movement either vertically or
laterally to bring the brake-surface 31, or the guiding shoes 32, into contact with
the track or guide of the rim.
It will be understood that in order to check or retard the forward movement of
the machine, the handle-bars are drawn upward and rearward or toward the rider,
in order to bring the central bearing surface 31, in contact with the apex of the
V-shaped track or guide. To guide the machine to the right, the handle-bars are
moved laterally to the right in order to bring the right hand lateral bearing
surface 32, into contact with the right side of the track or guide; and in order to
turn the machine in the opposite direction, the handle-bar is moved to the left to
bring the left hand guiding surface in contact with the left surface of the track
or guide.
It will be seen from the foregoing description that the construction of the
machine is compact and simple. The preponderance of weight is arranged below
the axis of the rim, thus increasing the stability and making it easier for the rider
to maintain the proper equilibrium, and the motion imparted to the crank-shaft is
communicated directly to the driving-wheel, and at the same time to the spindle of
the rim, whereby any desired speed may be attained.
The driving wheel is preferably made of a diameter equal to one-fourth that of
the rim, and the gear or chain-wheel which is carried by the crank-shaft and is
connected by a chain to the chain-wheel on the driving-shaft has a diameter which
is four times that of said chain-wheel on the driving-shaft, whereby one revolution
of the crank-shaft produces one complete revolution of the rin, and therefore the
chain-wheels, whereby motion is communicated from the crank-shaft to the spindle
of the rim, may be made of the same size throughout to cause an effective
transmission of power without causing binding or cramping of the parts.
It will be seen, furthermore, that the entire weight of the driving mechanism
and the rider is carried by the rim and is communicated thereto through the
driving and guiding wheels, no weight being sustained by the spiudle of the rim,
thereby still further increasing the stability of the structure, and decreasing the
friction of the moving parts.
Various changes in the form, proportion, and the minor details of construction
may be resorted to without departing from the spirit of the invention or sacrificing
any of the advantages thereof.
It will be seen, furthermore, that the propulsion of the machine is accomplished
more by gravity applied to the portion of the rim in advance of its contact with

page_text: the ground or surface over which the machine is passing, and that the arrangement
of the pedals close to the lower side of the rim enables the rider to control the
machine with greater ease; also, inasmuch as the brake contacts with the rim in
rear of the vertical plane of the seat, and hence in rear of the center of gravity of
the rider and machine, the application of the brake throws the weight from the
front to the rear, and thus serves to check the machine by transferring the center
of gravity as well as by causing frictional contact with the rim.
Having described my invention, what I claim is—
1. In a unicycle, the combination with a rim having a central divided spindle
held in place by radial spokes, of a bearing frame having extensible arms
fulcrumed upon the spindle of the rim, a driving wheel having its shaft mounted
in said frame and bearing upon the inner periphery of the rim, a guiding wheel
also mounted in the bearing-frame and bearing upon the inner periphery of the
rim, a crank shaft provided with pedal cranks, and connections between the crank-
shaft and the shaft of the driving-wheel, substantially as specified.
2. In a unicycle, the combination with a rim having a central divided spindle
held in place by radial spokes, of a bearing frame having extensible arms
fulcrumed upon said spindle upon opposite sides of the plane of the rim, a driving
wheel having its shaft mounted in bearings in the bearing-frame, a guiding-wheel
mounted upon the bearing-frame, a crank-shaft, connections between the crank-
shaft and the shaft of the driving-wheel, and independent connections between the
crank-shaft and the spindle of the rim, substantially as specified.
3. In a unicycle, the combination with a rim having a central divided spindle
held in place by radial spokes, of a bearing-frame having extensible arms fulcrumed
upon said spindle upon opposite sides of the plane of the rim, a driving-wheel
having its shaft mounted in bearings in the bearing-frame, a guiding-wheel
mounted upon the bearing frame, a crank-shaft, chain-wheels carried by the crank-
shaft and the shaft of the driving-wheel, a chain connecting said chain-wheels, a
countershaft having chain-wheels, chain-wheels fixed to the spindle of the rim upon
opposite sides of the plane of the rim, a chain-wheel upon the crank-shaft with one
of the chain-wheels upon the countershaft, and chains connecting other chain-
wheels upon the countershaft with said chain-wheels upon the spindle of the rim,
substantially as specified.
4. In a unicycle, the combination with a rim having a central spindle, a bearing-
frame fulcrumed upon said spindle, driving and guiding wheels mounted upon the
bearing frame and bearing upon the inner periphery of the rim, and means for
imparting motion to the driving-wheel, of a braking and guiding mechanism having
a shoe provided with a central bearing surface to engage the inner periphery of the
rim, and lateral bearing surfaces to engage either side surface of the rim, and
means for operating said shoe, substantially as specified.
5. In a unicycle, the combination with a rim, having a V-shaped track or guide
and a central spindle, of a bearing-frame fulcrumed upon said spindle and provided
with extensible arms, driving and guiding wheels mounted upon the bearing-frame
and bearing upon the V-shaped track or guide of the rim, means for imparting
motion to the driving-wheel, and a braking and guiding mechanism comprising a
shoe having a central and opposite lateral bearing surfaces, the central bearing-
surface being adapted to engage the apex of the V-shaped track or guide, and the
lateral bearing-surfaces being adapted to engage either side surface of said track
or guide, and a stem carrying said shoe having a universal connection with the
bearing-frame and provided with a handle-bar, substantially as specified.
Dated this 13th day of November 1895.
GEO. H. HOLGATE,
Agent for Applicant.