A NEW OR IMPROVED METHOD OF PROPELLING CARRIAGES WITH OR BY COMPRESSED AIR, AND APPARATUS THEREFOR
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by William Hammant at the Office
of the Commissioners of Patents, with his Petition, on the 2nd
May 1872.
I, WILLIAM HAMMANT, of Bouverie Street, Fleet Street, in the City
of London, Managing Clerk, do hereby declare the nature of the said
Invention for "A NEW OR IMPROVED METHOD OF PROPELLING CARRIAGES WITH
OR BY COMPRESSED AIR, AND APPARATUS THEREFOR," to be as follows:―
The object of my Invention is the production of an apparatus or
arrangement for compressing atmospheric air, storing it, and using or
applying it as a motive power in propelling carriages on common roads,
| tramways, and railways.
The means by which I propose to carry out in practice my said
Invention, are as follows:-Taking, for the purpose of illustration, a
On a
light four-wheeled carriage for ordinary or common roads.
strong frame fixed under the floor of the carriage I place a series of
air chambers curved somewhat like the outline of a smith's bellows,
wherein the air is compressed and stored; these chambers consist of
strong pipes or tubes of gun metal or other suitable material, varying

page_text: in number and diameter according to the size and weight of the
carriage to be propelled; in this case I assume that four of these
tubes, of about one-and-a-half inches internal diameter, to be requisite.
The entrance end of each tube is provided with a valve or screw plug
to close it when charged. The exit ends of the series of tubes are
united to av shaped piece of metal, cast solid and bored with holes
corresponding to the number of tubes, their internal diameters, and
their respective positions. The said holes are bored from the wide part
of the y towards its point, and all terminate near the said point thereof
in one common channel or outlet pipe. At or near the point of junction
between the said V shaped piece of metal and each of the said tubes
respectively is a screw plug so formed and fitted as to effectually close
the tube or leave it fully open, as desired. These, the main air cham-
bers are chiefly supplied with compressed air by means of an air force
pump, worked by the feet (or otherwise) of the person or persons
travelling in the carriage by means of a heel or toe treadle.
It will be readily understood that by closing the exit ends of these air
chambers the said chambers can be charged with compressed air before
setting out on a journey, and also whilst stopping on the way or what
is called "baiting," by working the said force pump. At the pointed
end of the said V piece of metal I fix an ordinary slide valve cylinder,
fitted with a piston and piston rod in the usual way. On turning one
of the screw plugs at the V or exit end of the air chambers to open the
communication between the said main air chambers and the entranco
air chamber of the said cylinder the highly compressed air in the
former rushes into the latter and thence into the said cylinder, thereby
moving the piston up and down or to and fro as is done by steam and
other compressed gases or vapours. The motion of the piston actuates
in the usual way a cranked axle, to which a pair of the carriage wheels is
fixed. The air after performing its duty in the said cylinder is ejected
or rushes out with considerable force into a small air chamber on the
opposite side of the said cylinder, and which I purpose utilizing by
directing it from a single opening in the outside of the said small air
chamber against a fan wheel. This fan wheel is constructed of metal or
other suitable material, and consists of a circular plate or disc with
blades attached thereto projecting therefrom at such an angle as will
catch or receive the ejected blast in the most efficient way. 1 enclose
the said fan wheel in a box or case having an opening towards the

page_text: front of the carriage so as to catch or admit air when the carriage
is in motion, thus assisting the revolution of the said fan wheel. This
fan wheel is employed in working a small air force pump to assist
in re-charging the air chambers after they have parted with their com-
pressed air.
I further propose to utilize the power gained by the momentum of
the carriage when going down a hill or an incline, by an improved
brake, as follows:-Around the inside of the rim of one of the hind
wheels of the carriage I fix a series of teeth or cogs so placed that
the teeth or cogs of a smaller wheel attached to the aforesaid strong
frame will gear therein. The axle of this smaller wheel works in a
vertical slot in the side of the frame when the brake is not required
to act, a spring fixed to a projection on the outer side of the said frame
lifts the said axle of the smaller wheel to the top of the slot, and thus
moves the cogs of the smaller wheel out of gear with those of the large
or carriage wheel; when it is required to apply the improved brake,
I force the said axle down to the bottom of the said slot by a lever, and
thus put the two wheels into gear with each other, when the smaller
one is carried or forced round with considerable speed. Attached to
this wheel by suitable gearing is a strong air force pump, varying in
size and capacity according to the weight and size of the carriage.
The vehicle may be steered by any of the usual methods employed for
that purpose.