IMPROVEMENTS IN APPARATUS CONTROLLING THE SUPPLY OF STEAM TO PARTS OF STEAM ENGINES.
Year: 1881

page_text: LETTERS PATENT to Sam Hallam, of Manchester, in the County of Lancaster,
Engineer, for an Invention of "IMPROVEMENTS IN APPARATUS
CONTROLLING THE SUPPLY OF STEAM TO PARTS OF STEAM ENGINES.".
FOR
(Void by reason of the Patentee having neglected to file a Specification in
pursuance of the conditions of the Letters Patent.)
PROVISIONAL SPECIFICATION left by the said Sam Hallam at the Office
of the Commissioners of Patents on the 30th July 1881.
SAM HALLAM, of Manchester, in the County of Lancaster, Engineer. "IMPROVE-
MENTS IN APPARATUS FOR CONTROLLING THE SUPPLY OF STEAM TO PARTS OF
STEAM ENGINES."
My Invention relates to the valves and valve gear of steam engines, and has for
its object to obtain a variable.cut-off with a prompt action of the valves, and a
free exhaust. I employ an auxiliary steam piston to actuate the main valve, and
I provide the cylinder in which the said piston is fitted with a valve or with
valves, which is or are actuated by the valve gear to cause the requisite movements
to be imparted to the main valve in order that the steam may be admitted to and
be cut off from the main cylinder, and the exhaust port or ports be opened at the
required times. I actuate the auxiliary valve spindle by means of a lever, which
is mounted upon a fulcrum which is carried by the main valve spindle, and I
connect the said lever with the valve gear. When the spindles are so connected,
the movements of the main valve have to some extent a controlling effect upon the
movements of the auxiliary valve. Steam is admitted to the auxiliary cylinder to
open the main valve for the admission of steam and to close the said valve at a
suitable period of the stroke of the engine, the exhaust cavity or passage being
adapted to maintain a free exhaust after the steam has been cut-off. Any suitable
TD
1

page_text: valve gear may be employed to actuate the auxilliary valve. In one arrangement
I connect the spindle of the valve with a link, which is connected by one end to a
second link, and by the other end to a block which is caused to slide in an inclined
slot or race, or to a lever which causes the said end to travel in an inclined path.
One end of the second link is connected with the connecting rod of the engine, and
the other end is jointed to a weigh lever, or is caused to travel.in a path which is
on a line, with respect to which the path of travel of the end of the first link is
inclined. The period of cut-off is regulated by varying the inclination of the last
named path, and the engine is reversed by reversing the direction of inclination.
In another arrangement the valve is actuated by means of a slotted lever which
is mounted on a fulcrum which is carried by a vibrating lever. The said vibrating
lever receives motion from the main connecting rod or from a reciprocating part
of the engine, and an arm on the slotted lever is connected by means of a link
with the connecting rod, whereby the slotted lever is caused to vibrate upon its
fulcrum. The valve connecting rod is connected with a block which slides in the
slot in the lever. By moving the said block in the slot, the supply of steam is
regulated, and the engine is reversed when required. This motion is applicable
to be used in connection with other arrangements of valves than are herein
referred to.