IMPROVEMENTS IN THE WHEELS OF ENGINES USED FOR AGRICULTURE OR TRACTION OF COMMON ROADS OR OTHER SURFACES
Year: 1871

page_text: "
PROVISIONAL SPECIFICATION left by Saint John Vincent Day at the
Office of the Commissioners of Patents, with his Petition, on the
22nd August 1871.-A communication from abroad by Alexander
Campbell and Robert Clark, both of Sacramento, in the State of
California.
I, SAINT JOHN VINCENT DAY, of Glasgow, in the County of Lanark,
North Britain, Consulting Engineer, do hereby declare the nature of the
said Invention of "IMPROVEMENTS IN THE WHEELS OF ENGINES USED FOR
AGRICULTURE OR TRACTION OF COMMON ROADS OR OTHER SURFACES," to be as
follows, that is to say :-
This Invention relates to improvements in the arrangement or con-
struction of the wheels of that class of engines which are used for
agricultural purposes, or for traction on roads, streets, or over cultivated
or uncultivated land, and its object is to obtain an elastic tyre or rim
to the said wheels, so that the adhesion of the same to the surface on
which the engine travels, or to the rope passing round the clip wheel,
is rendered very efficient.
The driving wheels are provided with elastic naves or bosses, and
flexible tyres of india-rubber, or of a combination of india-rubber and

page_text: canvas, leather, or other similarly pliable or elastic material. On the
outside of the tyres endless rails, having their edges bent up over the
sides of the tyres and rims of the wheels, are fixed. The endless rails
are provided in order that the engine may be more casily and smoothly
traversed over soft ground, and by forming the wheels with elastic naves
the use of the ordinary springs on which to support the boiler and
other parts of the body of the engine is obviated. The spokes or arms
of the driving wheels are made of T or angle iron, and by preference
placed diagonally, thereby giving the wheels great strength and stiffness.
The leading wheels of the engines are provided with flexible india-rubber
or other clastic tyres, and on the inner and outer sides of the tyres of
these wheels blocks of iron or steel, whose length is slightly greater
than the width of the tyres, are placed, and secured together by bolts
or rivets passed through the flexible tyres.
In order to afford still greater elasticity india-rubber or spiral metallic
springs are placed between the inner blocks or strips of iron or steel
and the plate forming the inner side of the rim of the wheel, by which
means the machinery is further relieved from jolting whilst travelling
over rough or uneven ground. The wheels now last described may also
be used as driving wheels. The clip wheel of the said engines is so
arranged that it can be connected or disconnected as desired. The body
of the said wheel is formed in halves which are bolted together, suitable
curved openings being formed in each piece to receive the inner pro-
jecting parts of the clips, which are arranged on the "toggle joint"
system, so that when the pressure of the hauling rope forces them
inwards towards the centre of the rim of the wheel they close in on
the rope and prevent it from slipping. A band of iron or steel is placed
in the wheel, which fits close around the inner side of the clips, so that
when the clips on one side of the wheel are pressed inwards by the rope
the band of iron or steel is also pressed inwards and forced against the
clips on the opposite part of the wheel, thereby opening the clips at the
places where the rope is entering and leaving the wheel, thus preventing
the clips from chafing the rope. Between the joints where the two
parts of the pulley are bolted together a piece of india-rubber or other
elastic and compressible material is fixed.