Year: 1898

page_text: I, FRITZ DÜRR, of 97, Alt Moabit, Berlin, in the Empire of Germany, Engineer,
do hereby declare the nature of this invention to be as follows:―
This invention has for its object an improvement in valve gearings for four
stroke gas engines in which the power for lifting the valves is conveyed by means
of cogwheels. The present improvement consists in that the cogwheels are not
utilized for transmitting the power necessary for lifting the valves but merely
for throwing in and out of action a link connecting the distributing mechanism
or gear with a cam disc or eccentric. The ratio of transfer of the wheels may
be suitably selected to suit the method of working of each motor construction
This improvement is shown in the accompanying drawings;
Figure 1 being a longitudinal section of the distributing or valve mechanism
in a vertical gas engine in connection with the discharge valve, whilst the suction
valve is assumed to be an automatically acting one;
Figure 2 is a sectional side view of same;
Figure 3 shows a portion of the engine with the distributing gear in elevation,
whilst
Figures 4 and 5 are details of the distributing gear.
The arrangement of the separate parts of the distributing or valve gear is as
follows:-
The crank mounted in the engine frame is provided with a spindle a project-
ing to the outside on which spindle a casing s is mounted. The spindle a also
carries a cam disc e shown in elevation in Figure 4 and a small cogwheel b.
Both these parts are enclosed in the casing s. A cogwheel e engaging with the
cogwheel is mounted in the casing, which cogwheel carries a smaller cam
disc d shown in elevation in Figure 5. A valve spindle K is adjustably arranged
in the upper part of the casing and carries at its lower end a swinging pawl f.
pivotally
The downwardly projecting end of this pawl bears against an arm
arranged in the casing and standing in turn in engagement with the cam disc e.
A lateral arm g on the pawl 7 engages with the smaller cam disc d.
The working of this distributing or valve gear is as follows:--
C
The cam disc e raises the arm at each revolution. By this means the pawl f
and with it the discharge valve would be lifted also at each stroke if the
pawl were not forced away laterally at each second revolution by the lateral
arm being acted on by the second cam disc which is rigidly connected with
the cogwheel and said pawl thus being brought out of reach of the arm h. In
order that this displacement may more easily take place, the cam disc e is cut
away slightly at the part n. During this part of the course the pawl ƒ can
freely drop, in case through a too rapid speed of the engine it drops too late for
engagement. In this case a regulation after the manner of the well known
pendulum or oscillating, regulations is obtained.
In place of a cam disc e and pawl f. an eccentric may equally voll be employed

page_text: in order to produce an up and down movement of the steering or distributing
members (f and K). Even in the case of an eccentric arrangement however the
action of the same on the valve may be partially suspended or removed by the
same means d and g.
Dated thin lat dox of Octahan 1000
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
An Improved Distribution or Valve Gear for Fourstroke Gas Engines.
I, FRITZ DÜRR, of 97, Alt Moabit, Berlin, in the Empire of Germany, Engineer,
do hereby declare the nature of this invention and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:-
This invention has for its object an improvement in valve gearings for four
stroke gas engines in which the power for lifting the valves is conveyed by means
of cogwheels. The present improvement consists in that the cogwheels are not
utilised for transmitting the power necessary for lifting the valves but merely
for throwing in and out of action a link connecting the distributing mechanism
or gear with a cam disc or eccentric. The ratio of transfer of the wheels may
be suitably selected to suit the method of working of each motor construction.
This improvement is shown in the drawings accompanying the Provisional
Specification.
Figure 1 being a longitudinal section of the distributing or valve mechanism
in a vertical gas engine in connection with the discharge valve, whilst the suction
valve is assumed to be an automatically acting one;
Figure 2 is a sectional side view of same;
Figure 3 shows a portion of the engine with the distributing gear in elevation,
whilst
Figures 4 and 5 are details of the distributing gear.
The arrangement of the separate parts of the distributing or valve gear is as
follows:
The crank mounted in the engine frame is provided with a spindle a project-
ing to the outside, on which spindle a casing is mounted. The spindle a also
carries a cam disc e shown in elevation in Figure 4 and a small cogwheel b.
Both these parts are enclosed in the casing s. A cogwheel e engaging with the
cogwheel is mounted in the casing, which cogwheel carries a smaller cam
disc shown in elevation in Figure 5. A valve spindle K is adjustably arranged
in the upper part of the casing and carries at its lower end a swinging pawl f.
The downwardly projecting end of this pawl bears against an arm b pivotally
arranged in the casing and standing in turn in engagement with the cam disc e.
A lateral arm 9 on the pawl f engages with the smaller cam disc d.
The working of this distributing or valve gear is as follows:-
The cam disc e raises the arm'h at each revolution. By this means the pawl f
and with it the discharge valve z would be lifted also at each stroke if the
pawl were not forced away laterally at each second revolution by the lateral
arm g being acted on by the second cam disc d which is rigidly connected with
the cogwheel c and said pawl thus being brought out of reach of the arm h. In
order that this displacement may more easily take place, the cam disc e is cut
away slightly at the part n. When this part n of the cam disc e is in the above-

page_text: mentioned position the pawl f can also again freely engage the arm 6 unless it is
too late to do so owing to the rapid speed of the engine.
In place of a cam disc e and pawl f, an eccentric may equally well be employed
in order to produce an up and down movement of the controlling or distributing
members (and K). Even in the case of an eccentric arrangement however the
action of the same on the valve may be partially suspended or removed by the
same means and g.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is: -
1. A distribution or valve gear for four stroke gas engines, characterised by
the controlling or distributing member (K) which is operated by a rotating cam
disc or eccentric e being withdrawn at a suitable moment from the action of said
cam disc or eccentric (e) by a swinging pawl (f) carried by the lower end of
the distributing member (K) being pressed to one side by means of a pair of cog
wheels (b) having a suitable ratio of transfer and a cam disc or eccentric (d)
mounted on one of the cogwheels (c) substantially as described.
2. A form of construction of the valve gear herein before described for four
stroke gas engines, characterised by the small cogwheel (b) being mounted on
a prolongation (a) of the crank shaft, whilst the larger cogwheel (c) with the
cam disc (e) is mounted in a casing (s) located on the extension (a) of the crank
and on the distributing member (k) substantially as described.
Dated this 17th day of March 1899.
3
W. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.