IMPROVEMENTS IN BICYCLES AND TRICYCLES
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Alfred Betton and William Trow at
the Office of the Commissioners of Patents on the 16th October 1877.
ALFRED BETTON and WILLIAM TROW, both of Birmingham, in the County of
Warwick, Machinists. "IMPROVEMENTS IN BICYCLES AND TRICYCLES."
Our improvements consist, first, in giving great rigidity to the front or principal
wheels of bicycles and tricycles.
The pressure of the foot upon the crank of the bicycle or tricycle is transmitted
through the hubs of the wheel to the spokes, and any resistance to the rotation of
the wheel has to be borne by those portions of the spokes which are fixed in the
hubs.
When the metallic rods constituting the spokes are very light in substance, there
is a tendency in the spokes when great resistance is offered to the advance of the
bicycle or tricycle, as in ascending a steep hill, to yield at their junctions with the
hubs, and sometimes to take a permanent set. In order to counteract this tendency
we fix on the axis of the front or principal wheel and between the hubs, four radial
equidistant arms. These four arms virtually form two rigid bars fixed to the axis,
and crossing each other at right angles, and we will herein-after call each pair of
the arms in the same right line, a bar.
To the extremities of each of these bars, rods, or strong wires are attached, the
extremities of these rods being connected to the rim of the wheel. Each of the said
two rods and the bar constitute a triangle, the base being the bar, and the summit
the point in the rim in which the rods terminate.
As each bar serves as the base of two triangles, one on either side of it, there are
four equidistant triangles in the plane of the wheel, their bases crossing the axis,
and their summits being in the rim. The said triangles give great rigidity to the
wheel and prevent the yielding of the hubs of the wheel herein-before referred to;
that is, such rigidity is given to the combined wheel and axis, that the rotation
given to the latter by the foot is transmitted to the wheel without any yielding at
the hubs.

page_text: Our improvements consist, secondly, in preventing the tremulous motion in the
seats of bicycles and tricycles, as ordinarily constructed.
We effect this object in the following manner:-The curved bar which connects
the fore and hind wheels together and which is commonly called the backbone of
the bicycle or tricycle, is ordinarily connected to the fork of the fore wheel by a
swivelling inelastic junction, and the vertical jumping motion of the wheel as it
passes over pebbles or small obstacles is communicated to the backbone and through
it to the seat carried by it.
We connect the said fork with the backbone in the following manner:-The
front end of the backbone carries a vertical tubular piece or socket through which
the vertical axis of the fork passes, and which axis terminates in the guiding handle
of the bicycle or tricycle. Within the said socket and around the axis of the fork
is a strong coiled spring, the upper end of which bears against a shoulder on the
upper part of the socket, and the lower end upon a shoulder on the said axis.
The said axis is thus capable of a slight vertical sliding motion within the said
socket, the coiled spring keeping the socket at its highest position on the axis
excepting when a sudden vertical motion (as when the bicycle or tricycle passes
over a pebble) is given to the axis, when the spring yields, and does not transmit,
or transmits only in a slight degree the said motion to the backbone and seat.
Our improvements consist, thirdly, in constructing a tricycle in the following
manner: We construct and arrange the parts of the tricycle in a way essentially
resembling the construction and arrangement of the parts of a bicycle, excepting
that in place of one small hind wheel we employ two. For this purpose the
rear end of the backbone is made into a fork. Each arm of the fork terminates
in another fork, between the arms of which last-named forks the two hind
wheels are supported and work; or the two hind wheels may be fixed on the
same axis, and the latter work in bearings in the first-named fork.
The tricycle thus resembles a bicycle excepting that the hind wheel is replaced
by two parallel wheels near each other. These hind wheels give with the front
wheel a slight base of three points, on which the tricycle will stand on level ground,
and which slight base gives great assistance to a learner.