Improvements in Internal Combustion Engines.
Year: 1896

page_text: Date of Application, 4th Dec., 1896
Complete Specification Left. 31st Aug. 1897-Accepted, 9th Oct., 1897
PROVISIONAL SPECIFICATION.
Improvements in Internal Combustion Engines.
I, HENRY CAPEL LOFFT HOLDEN Major Royal Artillery Royal Arsenal Woolwich
do hereby declare the nature of this invention to be as follows:-
My invention consists of a new form of valve gear for operating the exhaust and
if necessary the admission valves of internal combustion engines, such as gas and
oil engines, and is more especially applicable to those which work on the well
known Otto cycle. In such engines the exhaust valve is only opened once in every
four strokes of the piston.
During the first forward stroke the explosive mixture is drawn into
the cylinder, the admission valve or valves being opened automatically
by the suction of the piston or mechanically by the means hereafter
described, on the second or return stroke the mixture is compressed, on the third
forward stroke the mixture is exploded and on the fourth the return stroke the
products of combustion are expelled through the exhaust valve which is operated
by the following means.
A Horizontal or vertical rotating shaft as may be necessary to suit the design of
engine is arranged with its axis parallel to the axis of the niston rod or piston rods
if there be more than one as in two or more cylinder engines, and this same shaft
carries a sliding piece which works to and fro on the shaft with the motion of the
piston or pistons being generally attached to the rod, rods, crosshead or crossheads.
This shaft carries at each end of it inclined planes or equivalent devices which
are fixed to the rotating shaft and so arranged that the shaft is moved round a
quarter of a revolution, the movement being always in the same direction, during
the latter portion of each forward and backward stroke of the piston; this
rotative movement being obtained by the action of the sliding piece, which has
only the to and fro movement of the piston, on the inclined planes which are fixed
to the rotating shaft.
The rotative movement of the shaft thus obtained is utilized to work the exhaust
valve or valves and if necessary the admission valves through the intermediate
agency of excentrics or cams actuating the valves direct through their spindles or
through the agency of levers, or other similar devices which are in common use
for this purpose.
Dated this Third day of December 1896.

page_text: the same is to be performed, to be particularly described and ascertained in and by
the following statement:-
My invention consists of a new form of valve gear for operating the exhaust
valves and if necessary the admission valves of internal combustion engines, such
as gas and oil engines, and my invention is specially applicable to engines, having
one or more cylinders, working on the four cycle system generally known as the
Otto system, although it can be easily modified so as to be applicable to engines
working on any other cycle.
In the accompanying drawings, my invention is shown as applied to a four
oylinder internal combustion engine as described in my Patent No. 11491 of 1896.
Fig. 1, shows in plan such portions of the valve gear and engine as are necessary
to explain my invention; and Fig. 2 shows the essential features of the valve gear
in its simplest form. The valve gear in these Figs. 1 and 2 is shown applied to a
four cylinder four cycle engine.
It is however applicable to engines with less than four or even more than four
cylinders.
In Fig. 1, the four working cylinders are A 1. A 2. A3 and A4; each of
these cylinders has a working piston which is actuated by the explosion, and the
four pistons are actuated in succession one after the other.
The whole of the four pistons are connected together by the crosshead bar G
which passes through their piston rods, in such a manner that all the pistons move
simultaneously and in the same direction though only one piston is at any given
moment actuated by the explosion.
The exhaust valves belonging to the four cylinders are situated in the valve
boxes VV, and are opened to allow the exhaust gases to escape by the movement
of the rocking levers J J. The end of the lever J 1. controlling the exhaust valve
connected with the cylinder A1 the end of the lever J2 the exhaust valve of
cylinder A 2 and so on.
The crosshead bar G travels backwards and forwards with the movement of the
pistons and carries with it the piece B owing to the crosshead bar G passing through
the hole F which is made in B for that purpose.
The aforementioned piece B slides to and fro, with the crosshead bar G and the
pistons, on the shaft MM which in this manner acts as a guide for B. The
shaft M M is journalled in the valve blocks V V and it carries at either end of it a
cylindrical block DD with two spiral inclined planes cut on it at EE and also an
eccentric LL.
Both the blocks D D and the eccentrics LL are fixed to the shaft M M. From
both ends of B project in the manner shown in the figs. tappet pieces CC. of hard
steel or other suitable material. The function of these tappet pieces CC is to
engage with the inclined planes EE on the blocks D D and so to impart an inter-
mittent rotatory movement to the shaft M M through the intermediary of the
blocks DD which are fixed to the shaft M M. At either end of the shaft M M are
fixed eccentrics LL which eccentrics LL are embraced by the forked pieces KK,
these forked pieces K K being attached to the same arbors as the levers J. J.
The eccentrics LL are fixed to the shaft M M so that their major working axes
are 90°, ninety degrees apart. Thus the rotation of the shaft M M through the
above means causes the levers J J to rock on their pivots or arbors II and so to
actuate their respective exhaust valves. It will be understood that the relative
positions of the inclined planes EE, the tappet pieces CC, and the eccentrics L. L.
will be fixed according to the requirements of the particular engine to which they
are attached so as to actuate the levers JJ and open the valves at the correct
moment.
The inclination of the planes EE can be similarly modified with the same object
in view.
As shown in Fig. 1 an explosion has just taken place in the cylinder A 3 and the
piston in that cylinder is being driven forward; the forked piece K at this end
of the engine is in its middle position and therefore the lever J3. J 4. is horizontal

page_text: or equidistant from the exhaust valve spindles of A3 and A4, both these exhaust
valves are therefore closed, and piston of A4 is now drawing in its charge of
explosive.
At the other end of the engine the eccentric L is in the position to depress J2
and thereby to open the exhaust valve of A 2.
The exhaust valve of A 1 is closed, and the compression of the charge drawn in
the previous stroke is taking place ready for it to be fired when the piston has
passed the end of its stroke; and so the action goes on, the shaft MM being
rotated through 90° ninety degrees or one quarter revolution at each backward or
forward movement of the piston.
The admission valves of an engine may, if required, be operated in a precisely
similar way either by means of other eccentrics situated on the same shaft, or by
an entirely different shaft, or the same shaft and eccentrics that work the exhaust
valves may be utilized in connection with suitable levers and forked pieces similar
to those already described.
Although I have described my invention in more or less precise form as applied
to one particular pattern of engine, I do not wish to be undul limited thereto
except as enumerated in the claims.
With different patterns of engines modifications of details might be expedient
or necessary. For instance it might be expedient to reverse the relative positions
of the tappet pieces CC and the inclined plane blocks D D or again to actuate the
valve spindles directly by the agency of the eccentrics LL and without the
intermediary of the fork pieces KK, the arbors II and levers J. J.
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. In an internal combustion engine the combination of shaft, tappet pieces,
inclined planes, eccentrics, forked pieces, and levers or their mechanical
equivalents substantially as described and for the purposes set forth.
2. The valve gear substantially as described.
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