A PROGRESSIVE LEVER, BY WHICH IS OBTAINED AN INCREASE OF POWER OVER THE AMOUNT OF POWER APPLIED
Year: 1856

page_text: application for Letters Patent was not given within the time prescribed
by the Act.)
PROVISIONAL SPECIFICATION left by John Evans at the Office of the
Commissioners of Patents, with his Petition, on the 31st July 1856.
I, JOHN EVANS, of Castleton, in the Parish of Monkton, in the County of
Pembroke, Annuitant, do hereby declare the nature of the said Invention for
"A PROGRESSIVE LEVER, BY WHICH IS OBTAINED AN INCREASE OF POWER OVER THE
AMOUNT OF POWER APPLIED," to be as follows:-
There is a frame seven feet long, eighteen inches wide, and three feet deep,
that is, in the clear, or between the timbers of the frame. The frame is made
of wood, squared three inches each way. In 'this frame there is fixed longi-
tudinally two levers made of iron; the long arms of each lever are four feet and
four inches long; the length of the short arms is thirteen inches on the top of
the frame. Over the extreme ends of the long arms of the levers is placed a
double crank of iron, one crank being at right angles to the other, and the
arms of the cranks are one foot from centre to centre. This double crank has
three journals or bearings working in brasses with iron pedestals, the centre
pedestal resting on a piece of timber three inches square. One end of this beam
is shouldered on to the end of the frame, the other end being shouldered on to
a cross piece of timber two feet and six inches from the end. On one end of the
axle of the double crank is placed a winch, which, being put in motion by one
man, cause the cranks to revolve, and the cranks by the connecting rods cause

page_text: the levers to rise and fall with a perpendicular stroke of two feet. On the arms
of each large crank next to the centre bearing is placed a weight of iron, pro-
jecting in a contrary direction to the crank, to which it is fastened as a
counterpoise to the weight that the crank with its connecting rod and lever
will have when the crank is placed horizontally beneath the before-mentioned
piece of cross timber. On the top of the frame is another piece of cross timber;
at the bottom of the frame and between these two pieces of timber are placed
four iron rods, one rod on each side of each lever, the levers thereby being made
to work steadily in their places. The levers rest or move on pins in two centre
props. To the ends of the short arms of the levers are attached two connecting
rods, and over them on the top of the frame is placed another double crank,
the arms of which are three inches from centre to centre, and, like the large
crank at the other end of the frame, has one of its cranks at right angles to its
other crank, and made to revolve by the connecting rods attached to the short
arms of the levers, so that both the large and small cranks revolve at the
same time, and as often as the winch in the man's hand does. This
completes the first machine; and all the others are alike, only of greater
power, and must be worked together, and so form one progressive lever. Each
frame has two compartments; one machine or set of levers is placed in each
compartment. The axle of the large crank in the second compartment is
placed in a straight line with the axle of the small crank in the first compart-
ment, the two axles being connected by a coupling box on the side of the
frame opposite to that on which the man stands; any number of frames may
then be made all like the first, but stronger, and bolted one to the other from
first to last, till the required amount of power is obtained. The frames and
the machines, or sets of levers and cranks, must be made larger as the power
increases, and after the second set of levers and cranks, then all the short arms
of the levers will be made one inch longer, that is to say, the short arms of the
first and second sets of levers and cranks will be thirteen inches, the short arms
of the third set will be fourteen inches, in the fourth set the short arms will be
fifteen inches, and in each succeeding set the short arms will be increased one
inch, thereby allowing the arms of the small cranks to be of a length in pro-
portion to their thickness, for the power will be continually increasing; and
although there may be several machines or sets of levers and. cranks, they
make together but one progressive lever, increased in power, but unaltered in
construction or form.