AN IMPROVED VALVE GEAR OR MOTION FOR STEAM AND OTHER MOTIVE-POWER ENGINES AND STEAM PUMPS
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by Gustav Albrecht Carl Bremme
at the Office of the Commissioners of Patents, with his Petition,
on the 30th March 1874.
I, GUSTAV ALBRECHT CARL BREMME, of Liverpool, in the County of
Lancaster, formerly of Unna, in Westphalia, in the Empire of Germany,
Civil Engineer, do hereby declare the nature of the said Invention
for "AN IMPROVED VALVE GEAR OR MOTION FOR STEAM AND OTHER MOTIVE-POWER
ENGINES AND STEAM PUMPS," to be as follows:-
This Invention relates to a new gear or motion for working the slide
valves of steam and other motive-power engines and steam pumps, and
consists in actuating the valve spindle or rod by means of a combined
lever and disc, quadrant, or their mechanical equivalent. The lever is
so arranged and combined with the disc or its equivalent that its
fulcrum is changed and its action reversed during the same stroke. The
lever may be attached to the valve spindle by means of a link or other
connexion. The lever may be worked by a link connecting it to the
piston rod of the engine or otherwise.
The peculiar features of novelty in the combination of the lever and
disc is that the lever changes its action during the same stroke that is

page_text: in the first part of the stroke it is a lever of the second kind, that is,
the weight is between the fulcrum and the power. During the same
stroke it becomes a lever of the first kind, that is, the fulcrum is
between the power and the weight. This change reverses the action of
the lever during one stroke.
In constructing a valve gear according to this Invention the lever is
pivoted on the surface and near the edge of a loose disc carried by a
suitable strap and bracket and in proximity to the valve spindle. The
lever works and has its stroke across the face of the disc, its stroke being
adjusted by two stops on the face of the disc and at the side opposito
the pivot or natural fulcrum of the lever. The other end of the lever
projects beyond the disc and is worked by a link actuated by the piston
rod of the engine or otherwise. The link connecting the lever with the
valve spindle or rod is between the pivot or natural fulcrum of the lever
and the centre of the disc. At the commencement of the stroke, when
the lever is of the second kind, its action is to draw out the valvo
spindle, and it continues to do this until it comes in contact with the
stop on the face of the disc, when its nature is changed and it becomes a
lever of the first kind. The same double action takes place on the
reverse stroke of the lever..
The gear is capable of being applied to work any class of slide valve
and adjusted for any cut off and set to the valve. To prevent the disc
from turning during the stroke by the steam pressure on the valve I
use a small toothed or friction wheel and pinion, the wheel working
loose on the face of the disc and the pinion fixed on the centre of the
disc. The wheel works in teeth on the concave surface of the strap
carrying the disc. In lieu of this friction studs or other suitable means
may be used for overcoming the pressure of the valve.
In lieu of the disc the lever may be arranged on a quadrant, triangle,
or other equivalent to the disc so long as the combination produces - the-
double action and reverses the order of the lever during one stroke as
herein-before described.