IMPROVED MEANS OF DESTROYING MOMENTUM AND RESTORING IT IN THE OPPOSITE DIRECTION, APPLICABLE TO RECIPROCATING MOVEMENTS IN THE STEAM ENGINE, AND PRINTING AND OTHER MACHINERY, AS WELL AS FOR BUFFERS OF EVERY DESCRIPTION
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by John Gill at the Office of the
Commissioners of Patents, with his Petition, on the 16th January
1864.
I, JOHN GILL, of Edinburgh, in the County of Mid Lothian, North Britain,
do hereby declare the nature of the said Invention of "IMPROVED MEANS OF
DESTROYING MOMENTUM AND RESTORING IT IN THE OPPOSITE DIRECTION, APPLICABLE
TO RECIPROCATING MOVEMENTS IN THE STEAM ENGINE, AND PRINTING AND OTHER
MACHINERY, AS WELL AS FOR BUFFERS OF EVERY DESCRIPTION," to be as follows,
that is to say-
This Invention has reference to the means employed for reversing the
motion of those heavier portions of machinery which have a reciprocating
movement, such as the beam and piston of a steam engine, the travelling type
table of a printing machine, the carriage of a lithographic press, and has for its
object in such cases to destroy in a gradual manner the momentum acquired
in the forward movement so as to prevent injurious concussion, and also to
restore the momentum in the opposite direction and thus enable increased
speed to be obtained with a saving of power and other advantages. It also
admits of general application as a buffer wherever it may be desirable to avoid
the consequences of direct impact, and for this purpose it has peculiar
advantages in respect of its perfect elasticity its capability of being enlarged
and elongated to any size so as to resist a great force and the extent of its
compressibility as well as in other respects.
The improved apparatus consists of a hollow metal cylinder closed at the
one end, into which is fitted an air-tight movable piston, so that if the piston

page_text: be inserted and pressed into the cylinder the air contained in the cylinder will
be compressed until it acquire an expansive force equal to the pressure applied
from without, and if this pressure be removed the piston will be forced back to
its original position by the expansion of the compressed air in the cylinder.
In applying this apparatus to aid in reversing the motion of those heavier
portions of machinery which have a reciprocating movement, the cylinder is
placed in the line of such motion, and is made of suitable diameter and length
so that the momentum of the reciprocating portions may be expended in
forcing the piston into the cylinder and compressing the air therein contained,
the expansive force of which will then reverse the motion and restore in the
opposite direction a momentum equal (except in so far as affected by the
friction of the parts) to that which had been just expended in the previous
forward motion. A similar apparatus would of course be placed at each end
of the reciprocating movement so that the motion might be reversed at either
end with the like facility.
The improved apparatus can be applied with great advantage for the
purpose of reversing the motion of the flat type table of a printing machine,
the carriage of a lithographic press, the piston rod and beam of a steam engine,
and generally to reciprocating movements in machinery of every description.
In every case the piston rod would be made of a convenient length, and be
suitably attached or brought into connection at the proper time with the part
having the reciprocating movement.
The improved apparatus is obviously capable of various modifications, both
in the form of its construction and the manner of applying it. For instance;
the hollow vessel in which the air is compressed may have other shapes
besides the cylindrical, and there may be an air chamber attached to the
cylinder besides the hollow in the cylinder. Instead of one cylinder at each
end of a reciprocating movement there may be two or more, and the
relative positions of the cylinder and the piston may be interchanged by
attaching the cylinder to the reciprocating part, and the piston to the frame
of the machine.
The improved apparatus is also applicable for railway and all other kinds
of buffers, and on a large scale might be placed on board ships with the
piston rod projecting from the bows through a water-tight collar, so as to
mitigate or prevent the concussion which would be caused by the vessel
accidentally running against a rock, or an iceberg, or another vessel. When
applied as a buffer merely to prevent concussion, and when it is wanted that
there should be no recoil, this result may be obtained by having a small
aperture in the piston, or in the end of the cylinder, so as gradually to allow

page_text: the compressed air to escape during compression; or there may be two
chambers or compartments in the cylinder separated by a valve so that the
compressed air in the inner chamber could not force back the piston, and the
air so compressed in the inner chamber would be allowed to escape gradually
by a small aperture in it. The piston would be drawn out to its original
position with greater facility by having a valve in it opening inwards.