IMPROVE- MENTS IN TRACTION ENGINES, AND IN APPARATUS FOR INDICATING THE PRESSURE OF STEAM
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Andrew Barclay at the Office
of the Commissioners of Patents, with his Petition, on the 10th
September 1862.
I, ANDREW BARCLAY, of Kilmarnock, in the County of Ayr, North Britain,
Engineer, do hereby declaro the nature of the said Invention for "IMPROVE-
MENTS IN TRACTION ENGINES, AND IN APPARATUS FOR INDICATING THE PRESSURE OF
STEAM," to be as follows:-
This Invention relates, in the first place, to certain improvements in the
construction and arrangement of traction engines, which improvements are
based upon an Invention of a similar kind for which Letters Patent were
granted to Mr. Andrew Barclay, dated 10th March 1862, No. 646.
Under one modification of the present Invention as applied to traction
engines of the "right-angled class," the crank shaft of each pair of engines has
its bearings at one end arranged in the side standard or frame, whilst the
other end is connected to the main axle, or to the centre of the driving wheel,
so that this end of the shaft vibrates with the motion of the spring of the
driving wheel, whilst the other end remains a fixture in its bearing. The
other pair of engines has its crank shaft arranged in like manner, the fixed
bearings being on opposite sides of the machine. In this way the vibrating
motion of the wheels, as they traverse over the inequalities of the road, is
imparted to one extremity of each crank shaft, but without affecting the
opposite ends, which revolve steadily in their bearings. The object of the
arrangement is to prevent the vibration of the driving wheels from affecting

page_text: the beat of the valves. The driving wheels are arranged one with a long
tubular axle, to which the wheel is keyed, and extending across the framing,
the other wheel is fitted with an axle, which passes through the tubular one,
and is fastened by a nut. Or the two axles may be arranged parallel, to rotate
in contact, and thus obtain an extended bearing surface when the engines are
driven at different speeds. The traction engine is coupled to the vehicle
accompanying it by a T-shaped connecting piece, which is carried on a vertical
spindle, its prolongation passing through two bushes carried by the framing of
the connected carriage. This arrangement admits of the lateral and vertical
movements of the coupled engine and vehicle. The traction engine may also
be guided as well as regulated in speed by means of a duplex break action,
which is operated by a single-hand lover, so that the motion may be checked
or the break applied to either side of the machine, and so guide it by the
different speeds of the driving wheels. The improved pressure gauge consists
of a metal or other chamber, formed in two parts, and divided by an elastic
air-proof diaphragm. Above the chamber is fitted a graduated glass tube,
partly filled with water, which rests on the elastic diaphragm. The pressure
of the steam raises the diaphragm and column of water, causing the air to be
compressed, and in the ordinary gauges the air escapes through the water
when subjected to long continued pressure, but by interposing the diaphragm
of elastic air-proof material this escape is prevented, and the gauge continues
correct in its indications.