Year: 1886

page_text: Date of Application, 12th June, 1886.
Complete Left, 14th Mar., 1887.
Complete Accepted, 10th June, 1887
I GUSTAV ALBRECHT CARL BREMME of 79 Windsor Road The Brook Liverpool in
the County of Lancaster, Engineer do hereby declare the nature of this invention to
be as follows:-
The invention relates mainly to marine engines, or to such engines as should have
a short crank shaft, or to engines in which it is desirable to get rid of or avoid the use
of excentrics on the crank shaft. The invention however is applicable to steam and
motive power engines generally.
The object is to so construct such engines that motion is communicated to valves by
means of novel connections and arrangements of parts receiving motion from the
connecting rod. In this manner the crank shaft is kept free from excentric and other
valve gear.
In carrying my invention into practice I mount in bearings a valve shaft free to
rotate on an axis parallel or nearly so to the crank shaft and give motion thereto from
the connecting rod by means of a crank arm and guide or equivalent mechanism. The
arm is secured to the connecting rod and the guide to the shaft, or vice versa. The
shaft gives motion to the valve by means of excentric crank or other desirable gear
connected thereto or driven therefrom in any convenient manner.
It will be obvious that more than one valve shaft may be used in each engine, and
that the position of the valve shaft, and the connections to the valve may be varied.
A convenient construction for driving the valve shaft from the connecting rod
consists in fitting one end of the crank arm in a bearing in the connecting rod or
prolongation thereof in which it is free to revolve, and the other end through a bush
or sleeve secured to the overhanging end of the valve shaft. It will be obvious that
the crank arm will slide to and fro in the bush or sleeve whilst it is being carried
round by the connecting rod.
JAMES JOHNSON,
Agent.

page_text: COMPLETE SPECIFICATION.
Improvements in Valve Gear for Steam and other Motive Power
Engines.
I GUSTAV ALBRECHT CARL BREMME of 79 Windsor Road The Brook Liverpool in
the County of Lancaster, Engineer do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
The invention relates mainly to marine engines or such engines as should have a
short crank shaft or to engines in which it is desirable to get rid of or avoid the use
of eccentrics on the crank shaft.
The invention however is applicable to steam and other motive power engines
generally.
The object is to so construct such engines that motion is communicated to valves by
means of novel connections and arrangements of parts receiving motion from the
connecting rod.
In this manner the crank shaft is kept free from excentrics and other valve gear.
In carrying my invention into practice I mount in bearings a valve shaft free to
rotate on an axis parallel or nearly so to the crank shaft and give motion thereto from
the connecting rod by means of a crank arm and guide or equivalent mechanism.
The arm is secured to the connecting rod and the guide to the shaft or vice versa.
The shaft gives motion to the valve by means of excentric crank or other desirable
gear connected thereto or driven therefrom: in any convenient manner.
It will be observed that more than one valve shaft may be used in each engine, and
that the position of the valve shaft and the connections to the valve may be varied.
A convenient construction for driving the valve shaft from the connecting rod
consists in fitting one end of the crank arm in a bearing in the connecting rod or
prolongation thereof and the other through a bush or sleeve secured to the overhanging
end of the valve shaft.
It will be observed that the crank arm will slide to and fro in the bush or sleeve
whilst it is being carried round by the connecting rod.
Figure 1 is a diagram illustrating the action of the gear when the longitudinal axis
of the valve shaft intersects the centreline of the engine.
Crepresents the centre of the crank shaft.
O the centre of the valve shaft which is parallel to the crank shaft.
D the centre of crank pin. CD-R the length of crank. G the centre of gudgeon
of the connecting rod or of the piston rod cross head.
G D L the length of the connecting rod.
The point of connection E hetween the crank arm and the connecting rod is in the
longitudinal axis of the connecting rod.
It will be easily understood from the diagram that if the crank is at dead point,
that is, if the centre D is in the centreline (CC) of the engine the centre E will also

page_text: -
E G.
L
be in that line, and that during a revolution of the crank, the centre E will describe
the closed curve marked in a dotted line, which curve closely resembles an ellipse
whose major axis is 2 R. and whose minor axis 2 R and further that the
motion of the centre E will cause the valve shaft to make one revolution on its
axis O during the revolution of the crank shaft, if the mechanical connection between
centres E and O is such as to allow the centre E to approach to and recede from the
fixed centre O.
The angles of rotation of the valve shaft (GOE) are at the beginning of the stroke
of less magnitude than the corresponding crank angles (G. C. D.) and they become
equal at or near completion of the half stroke of the piston. This difference in the
angular motion of the two shafts tends to improve the action of the valve as will be
easily understood.
As shewn in the drawing the distance C. O. of the valve shaft from the crank shaft
is equal to distance E. D. of point of connection from the crank pin and in con-
sequence the valve shaft angle (G. O. E.) is more than 90 degrees. This angular
advance of the valve shaft at this position of the crank is of advantage for early cut
offs, as will be easily understood.
To cause the valve shaft angle to be 90°, when the crank angle is 90°, it is only
necessary to reduce the distance C. O. and make it equal to distance E. T. and in
general by the alteration of the position O, of the valve-shaft within the closed curve
described by centre E the relative angular motion of the valve shaft may be modified
to suit any desired purpose. It will be obvious that the results above mentioned may
in part be obtained by altering the position of centre E. Figure 2 is a diagram
illustrating the action of the gear when the longitudinal axis of the valve shaft does
not intersect the centre line of the engine.
In this case it is preferred that the point of connection E should be the same
distance from the longitudinal axis of the connecting rod as the valve shaft is from
the centre line of the engine as shown on the drawing. The explanation given of
Figure 1 is substantially applicable to Figure 2. It will be obvious that the greater
the length of the connecting rod in relation to the crank the nearer will the curve
described by the centre E approach that of an ellipse.
The position of point O is chiefly determined by constructive convenience. It
will be seen that the point E instead of being located between the points G and D
of the connecting rod may be outside those points, the connecting rod being prolonged
for that purpose, and the position of point O is fixed to suit that condition.
Figure 3 is an end view, and Figure 4 a side view, of a portion of a vertical
marine engine to which the invention is applied. The crank arm A is a round
bar jointed to the connecting rod by means of an eye bolt E which is fixed to
the crank arm A and turns freely in a bush or bearing in the connecting rod.
The arm A passes through a sleeve guide or bush 5 on the overhanging end of
the valve shaft O, which is held in position by and turns freely in suitable bearings.
A single excentric is so fixed to the valve shaft O as to coincide in its throw
with the throw of the crank. To this excentric is attached the Bremme valve
gear described in the specification of Letters Patent No. 2037 of the year 1879 as
indicated by the thick black lines.
Figure 5 is an enlarged view of crank arm A eye-bolt E a portion of the connecting
rod K sleeve S and valve-shaft O illustrated and described under Figures 3 and 4:
but two. excentrics are fixed on the valve shaft O to which the ordinary link gear may
be attached.
Figures 6 and 7 shew a modification under which the connecting rod K drives two
shafts the one of which carries one excentric and the other is a crank shaft by which a
pump is driven.
Each crank arm A is a flat bar, one end of which is fitted and turns in suitable
bearings on a trunnion E fixed to the connecting rod K whilst the other end passes
through a suitable sleeve 5 at the end of one of the two shafts O.

page_text: It will be obvious that the excentric or crank, or excentrics or cranks, on the
valve shaft O or equivalents, may be connected to the valve or valves through any
suitable gear as well as through that shown.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed I declare that what I claim is :-
First. Valve gear constructed substantially as herein set forth.
Second. The combination with the connecting rod of a motive power engine of a
crank arm shaft other than the crank shaft, and connections for the purposes
set forth.
Third. Giving motion to valve gear of motive power engines by means of crank
arm mechanism coupled to a connecting rod substantially as set forth.
Fourth. The combination of the parts C. D. K. E. A. S and O or their equivalents
for the purposes set forth.