A NEW OR IMPROVED ALARUM FOR BICYCLES, TRICYCLES, AND OTHER VELOCIPEDES
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Robert Purdom at the Office of the
Commissioners of Patents on the 6th October 1877.
ROBERT PURDOM, of Birmingham, in the County of Warwick, Spectacle Manu-
facturer, "A NEW OR IMPROVED ALARUM FOR BICYCLES, TRICYCLES, AND OTHER
VELOCIPEDES."
My Invention consists of a new or improved alarum for bicycles, tricycles, and
other velocipedes, the parts of which alarum are constructed and arranged as herein-
after described.
My new or improved alarum is under the control of the person riding on the
bicycle or velocipede, and may at his pleasure be brought into and taken out of
action in a simple and expeditious manner, and the annoyance to the rider, which
attends the use of the ordinary alarum, which is in continuous action, is avoided.
My new or improved alarum is especially fitted for use with bicycles, and I will
describe it as applied to a bicycle, but the said alarum may also be applied to
tricycles and four-wheel velocipedes.
To the fork of the driving or front wheel of the bicycle I joint a cranked lever
turning in a vertical plane, the arms of the said lever being situated nearly at right
angles to one another. At the bottom of the short horizontal arm of this cranked
lever a small fork is made, between the branches of which fork a friction wheel
works. One end of the axis of this wheel carries an arm, having at its end a
jointed bell clapper or hammer, which clapper or hammer acts upon a bell fixed
to the horizontal arm of the cranked lever near the fork, carrying the friction
wheel.
The said friction wheel is situated over the front or driving wheel of the bicycle,
and in its normal position is out of contact with the said driving wheel, but the
friction wheel may, when required, be pressed into contact with and receive a
rapid rotation from the said driving wheel.
The cranked lever is held in its normal position, and the alarum taken out of
action by a coiled or other spring. The long, nearly vertical, arm of the cranked
lever passes to near the guiding handle of the bicycle, and is furnished with a long
cross bar, which said cross bar is situated parallel to the guiding handle, so that
the hands of the rider grasping the said guiding handle can at the same time press

page_text: the cross bar forward, and put the alarum into operation. By the rider pressing the
cross bar of the alarum the horizontal short arin of the cranked lever is depressed,
and the friction wheel brought into contact with the driving wheel of the bicycle.
A rapid rotation is thus given to the friction wheel, and the hammer or clapper on
its axis is thereby made to rapidly strike the bell, and give notice of the approach
of the bicycle.
By removing the pressure of the hands from the cross bar of the alarum near the
guiding handle the cranked lever takes its normal position by the action of its
spring, and the friction wheel is drawn out of the range of motion of the driving
wheel; the friction wheel comes to rest, and the bell is no longer sounded.
Instead of a bell a rattle or other sounding instrument may be operated upon
through the friction wheel.
In the case of a rattle, arms or tappets on the axis of the friction wheel act upon
the rattle instead of the hammer or clapper acting upon the bell.
Instead of fixing the alarum in the position described, that is, on the front part
of the bicycle it may be placed at the rear part. In this case the motion of the arm
operated upon by the rider is communicated by cords or bands to the friction wheel
at the rear, which latter is operated upon by the hind wheel of the bicyle. I prefer,
however, the arrangement first described.