Improvements in Valve Gear for Engines.
Year: 1893

page_text: Date of Application, 20'h July. 1893
Complete Specification Left, 21st Mar., 1894-Accepted, 25th May, 1894
PROVISIONAL SPECIFICATION.
Improvements in Valve Gear for Engines.
I, ALFRED COLLMANN, of Beatrixgasse 18, Vienna, Austria, Engineer; do
hereby declare the nature of this invention to be as follows:-
This invention has for its object to provide for a positive but sudden closing of
the admission valves for any desired expansion of steam.
I will describe the said invention with reference to the accompanying drawings
which shew various arrangements for carrying the same into effect.
Referring to the construction shewn at Figs. 1, and 2, the cam D is, by any
releasable trigger gear, either rocked on its axis x as at Fig. 1 or reciprocated
along a guide e e¹ Fig. 2, whereby a roller R Fig. or a head R Fig. 2 connected
with the valve stem either directly or through the medium of an intermediate
lever gear, is so actuated that the valve at V is operated in the following manner.
At first the valve is slowly raised a little and is then raised very rapidly to the
full height of its stroke, in which position it remains approximately till the
moment of closing. When the trigger gear (for instance by catches K' K2)
releases the rocking or the reciprocating cam D Fig. 1 or 2 at any desired
moment, the cam D is suddenly moved backwards either by a weight or by
steam, or spring pressure. Owing to the pressure closing the valve, the roller Ŕ
or head R bears constantly against the working surface of the cam D and the
latter is so shaped that the downward movement of the valve is very rapid at
first and is very much retarded towards the end of the valve stroke, so that
the valve is brought home on to its seat without any shock.
After the closing of the valve, the cam D continues to move backwards, entirely
leaving the roller R or bead R¹ free. This backward movement of cam D is
suitably controlled by a dash-pot arranged at L containing air, oil or other fluid.
The cam D rocking on the axis or reciprocating along guides, may also be so
arranged that its working surface is on the inside (for instance towards the axis x)
as shewn in Fig 14. Instead of guiding the cam D on fixed slides or round an
axis x, the cam D can also be guided by a link gear either in a straight or in a
curved line.
A special arrangement of this valve gear is shewn in Figs. 3 and 4. An
excentric E Fig. 4 operates the exhaust valve through the medium of a cam D¹¹
roller R and lever J".
The motion of the valve gear rod A B is either so derived from an eye ▲ on the
exhaust excentric E, or from a separate excentric, that the link B is moved
downwards during the action of the trigger gear. When the link B has nearly
reached its highest position, shewn in Fig. 3, the trigger pawl m engages with the
end of the arm n of cam D without any shock. If desired, a spring may be used
to assist in rendering this engagement of the catches quite noiseless.
When the link B moves downwards, the cam D acts upon the roller R and the
valve V is raised by the lever J at first slowly and then very rapidly to its full
stroke, which is about the same for all degrees of expansion.
By the expansion shaft W connected with the governor S Fig. 4, the stop w
is suitably adjusted and the trigger pawl m is released from the arm n by means
of the arm o connected with the said pawl striking against the stop w at the proper
moment.
A spring or weight in combination with a dash pot L now suddenly turns back
the cam D so that the roller R bearing against the cam D together with the
intermediate lever gear, causes the valve at V to be closed positively and almost

page_text: instantaneously, which motion is very rapid at first and very much retarded towards
the end of the valve stroke, this taking place for any desired degree of expansion.
At all degrees of cut-off the valve reaches its full opening stroke, and the
roller R bears against that portion of the working surface of the cam D which is
concentric with the axis x Fig. 1 or parallel to the guide e e¹ Fig. 2 and therefore
the pressure tending to close the valve does not react upon the trigger gear
and therefore the releasing of the latter is effected without any appreciable
resistance.
The advantages of the combined trigger and cam valve gear are the following:
Gentle and quiet engagement of the trigger pawls, gentle lifting off, and very rapid
raising of the valves to their full stroke (which is the same for all usual degrees
of expansion) and instantaneous but positive closing motion of the valves with a
gentle set-home on to the valve seats, an almost resistanceless releasing of the
trigger gear and therefore a very low resistance to the governor and very sensitive
and delicate governing with very small governors.
Another method of obtaining a similar action of the valve gear is shown in
Figs. 5, 6 and 7.
Any desired trigger gear actuates the lever H Figs. 5, 6 and 7, and raises the
admission valve V (connected with lever H Fig. 7 or with lever H" Figs. 5 and 6)
at first slowly but then very rapidly owing to the shifting of the point of contact
between the two levers H and H".
When the trigger gear is released, the reverse action will be produced.
The
By means of weights, steam or spring pressure, in combination with an air
or oil dash pot, the valve is closed first rapidly, then retarded in an instantaneous
but positive way by means of the shifting of the point of contact between
the levers H and H, and the valve is gently brought home on its seat.
levers H H may be arranged opposite each other as in Fig. 5 or the one below
the other as in Fig. 6 or the lever H" may be replaced by a fixed curved bearing
surface H" as in Fig. 7. Also in this gear the lever H actuated by the trigger
gear continues to move on after the closing of the valve and at the backward
movement, and leaves the valve quite free.
Dated this 20th day of July 1893.
ABEL & IBIRAY,
Agents for the Applicant.
CUMI LEID
DIMUIFICATION
Improvements in Valve Gear for Engines.
I, ALFRED COLLMANN, of Beatrixgasse 18, Vienna, Austria, 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 to provide for a positive but sudden closing of
the admission valves for any desired expansion of steam.
I will describe the said invention with reference to the drawings accompanying
my Provisional Specification which shew various arrangements for carrying the
same into effect.
Referring to the construction shewn at Figs. 1 and 2, the cam D is, by any
releasable trigger gear, either rocked on its axis as at Fig. 1 or reciprocated
along a guide el Fig. 2, whereby a roller R Fig. 1 or a head R' Fig. 2 connected
with the valve stem either directly or through the medium of an intermediate
lever gear, is so actuated that the valve at V is operated in the following manner.
At first the valve is slowly raised little and is then raised very rapidly to the
full height of its stroke in which position it remains approximately till the moment
of closing. When the trigger gear (for instance by catches K' K") releases the

page_text: rocking or the reciprocating cam D Figs. 1 or 2 at any desired moment, the cam D
is suddenly moved backwards either by a weight or by steam, or spring pressure..
Owing to the pressure closing the valve, the roller R or head R' bears constantly
against the working surface of the cam D and the latter is so shaped that the
downward movement of the valve is very rapid at first and is very much retarded
towards the end of the valve stroke, so that the valve is brought home on to its seat.
without any shock.
After the closing of the valve, the cam D continues to move backwards, entirely
leaving the roller R or head R' free. This backward movement of cam D is.
suitably controlled by a dash-pot arranged at L containing air, oil or other fluid.
The cam D rocking on the axis or reciprocating along guides, may also be so
arranged that its working surface is on the inside (for instance towards the axis æ).
as shewn in Fig. 1A. Instead of guiding the cam D on fixed slides or round an
axis r, the cam D can also be guided by a link gear either in a straight or in a
curved line.
A special arrangement of this valve gear is shewn in Figs. 3 and 4. An
excentric E Fig. 4 operates the exhaust valve through the medium of a cam D.
roller R and lever J.
The motion of the valve gear rod A B is either so derived from an eye A on the
exhaust excentric E, or from a separate excentric, that the link B is moved down-
wards during the action of the trigger gear. When the link B has nearly reached
its highest position, shewn in Fig. 3, the trigger pawl m engages with the end of
the arm n of cam D without any shock. If desired, a spring may be used to
assist in rendering this engagement of the catches quite noiseless.
When the link B moves downwards, the cam D acts upon the roller R and the
valve V is raised by the lever J at first slowly and then very rapidly to its full
stroke, which is about the same for all degrees of expansion.
By the expansion shaft W connected with the governor S Fig. 4, the stop w is
suitably adjusted and the trigger pawl m is released from the arm by means of the
arm o connected with the said pawl striking against the stop w at the proper
moment.
A spring or weight in combination with a dash pot L now suddenly turns back
the cam D so that the roller R bearing against the cam D together with the inter-
mediate lever gear, causes the valve at V to be closed positively and almost
instantaneously, which motion is very rapid at first and very much retarded
towards the end of the valve stroke, this taking place for any desired degree of
expansion.
At all degrees of cut-off the valve reaches its full opening stroke, and the roller R
bears against that portion of the working surface of the cam D which is concentric
with the axis & Fig. 1 or parallel to the guide e e¹ Fig. 2 and therefore the pressure
tending to close the valve does not react upon the trigger gear and therefore the
releasing of the latter is effected without any appreciable resistance.
The advantages of the combined trigger and cam valve gear are the following:
Gentle and quiet engagement of the trigger pawls, gentle lifting off, and very rapid
raising of the valves to their full stroke (which is the same for all usual degrees of
expansion) and instantaneous but positive closing motion of the valves with a gentle
set-home on to the valve seats, an almost resistanceless releasing of the trigger gear
and therefore a very low resistance to the governor and very sensitive and delicate
governing with very small governors.
Another method of obtaining a similar action of the valve gear is shewn in
Figs. 5, 6 and 7.
Any desired catch gear K K' actuates the ever H Figs. 5, 6 and 7, and raises
the admission valve V (connected with lever H Fig. 7 or with lever H" Figs. 5
and 6) at first slowly but then very rapidly owing to the shifting of the point of
contact between the two levers H and H
In Fig. 5 the lever K on moving upwards strikes against the arm K' of lever H
thus rocking the latter, and causing the valve V to open as described. In Fig. 7

page_text: the lever K on moving downwards engages with a link K¹ connected with the
lever H and thus causes the valve V to open. In Fig. 6 the lever K is adapted to
engage into a notch on an arm K' of lever H and on being rocked it raises the
lever H thus causing the valve V to be opened.
When the catch gear is released, the reverse action will be produced.
By means of weights, steam or spring pressure, in combination with an air or
oil dash pot, the valve is closed first rapidly, then retarded in an instantaneous but
positive way by means of the shifting of the point of contact between the levers H
The levers H H" may
and H', and the valve is gently brought home on its seat.
be arranged opposite each other as in Fig. 5 or the one below the other as in
Figure 6 or the lever H" may be replaced by a fixed curved bearing surface H"
as in Fig. 7. Also in this gear the lever H actuated by the trigger gear continues
to move on after the closing of the valve and at the backward movement, and
leaves the valve quite free.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. In valve gear for engines a cam D with straight or curved sides rocking on
an axis (or reciprocating in a straight or curved line) which is moved by any
catch gear in such a manner that by means of a roller R or stop R' working on
the face of such cam the valve directly or indirectly connected with the said roller
or stop, is at first slowly lifted off its seat and then rapidly raised to its full stroke
and that a sudden backward movement of the cam D is, produced by weights,
spring or steam pressure, after the catch gear has been released, whereby owing to
the relative movement of cam D and roller R or stop R¹ the valve is positively
and instantaneously closed, the closing movement being very much retarded
towards its end and the backward movement of the cam being assisted by a dash
pot filled with air, oil or other fluid substantially as described.
2. The special arrangement of the valve gear substantially as shewn in Figs. 3
and 4 with excentric rod A. B pawl m cam D and lever J whereby the valve is
positively but instantaneously closed, being at the same ti ne gently brought home
on to its seat substantially as described.
3. Obtaining a similar action of the valve gear to that referred to in the preceding
claim by combining any known arrangement of releasing catch gear with the
levers H and H" substantially as described with reference to and shewn in
Figs. 5, 6 and 7.
Mah 1001
ABEL & IMRAY,
Agents for the Applicant.