Internal-combustion engines – Multiple cylinder – Having rotary output shaft parallel to cylinders
Reexamination Certificate
2000-11-13
2002-08-20
McMahon, Marguerite (Department: 3747)
Internal-combustion engines
Multiple cylinder
Having rotary output shaft parallel to cylinders
Reexamination Certificate
active
06435145
ABSTRACT:
TECHNICAL FIELD
The present invention refers to an internal combustion engine with a sliding drive shaft, which can work both as a four or two-stroke Otto cycle engine, or as a two- or four-stroke Diesel engine, depending on the way in which it is built, being highly efficient in all versions.
Although in the industry a large variety of internal combustion engines pursuing the same purpose are already known, many of them working at even higher levels of efficiency, these nevertheless require parts which are somewhat complex to build, such as crankshafts, bearings, connecting rods and camshafts, with geometric forms that lead to, amongst other things, a considerable increase in the price of the end-product, as well as in its subsequent maintenance.
It is for this reason that in the present invention an easily constructed mechanism has been developed, the main features of which can be summarized as follows:
a) The mechanism does not have a crankshaft (a mechanism which requires great precision in its construction, complex machining and careful dynamic balancing).
b) The stroke of the pistons is not limited by the size of the crankshaft.
c) A greater number of cylinders are allowed for, resulting in more power in the same space, thus achieving a better power/weight ratio as well as a smoother-running engine.
d) It does not require connecting-rods, nor main nor connecting-rod bearings.
e) Construction costs are lower than those for equivalent engines so far designed.
f) The maintenance required is simpler.
g) Fuel consumption can be reduced as the piston stroke can be longer than that of conventional internal combustion engines.
h) Its construction requires only a few simple elements that are easily obtainable both industrially and commercially.
i) Several inlet and exhaust valves can be driven by one simple circular cam shaft.
j) The oil pan can also be cylindrical, thus simplifying engine lubrication and cooling.
k) The lubrication of the element which connects each piston with the drive shaft can be made easier by the action of the centrifugal forces developed within it as it rotates.
l) The camshaft, which can be mounted on concentric shafts, permits variable distribution regulation of the inlet and exhaust valves, improving the intake into the cylinders and providing strong coupling even at low and medium engine speeds.
m) The piston stroke, if so desired, can be variable, so that in special cases the compression ratio of the engine can be changed with the engine running.
RELATED PRIOR ART
U.S. Pat. No. 1,177,609 describes a means for converting reciprocating motion into rotary motion. The document describes a cylinder which may be part of a gas or steam engine or any other prime motor, in which a piston
2
is mounted to reciprocate and actuate a piston rod extending through the cylinder. Although the embodiment shown on
FIG. 2
seems to anticipate the present invention, this is not really so because this early engine development shows strong design handicaps. For example, the pins
22
in
FIG. 2
are received by the groove
21
of the cam following a single contact line and not a particular surface. The fact that all the piston's force is applied on thin grooves creates a very high pressure stress and premature material wear-out on the engagement parts. From a production point of view, groove
21
is difficult to create and needs special numeric control tools. In
FIG. 1
, the groove
10
is also difficult to create because it should be in all its track perpendicular to the rotation axis of the fly-wheel or band pulley
13
and will also need special and sophisticated tooling. A major difference among the mentioned document and the present invention is the fact that in the former the engagements zones are engraved into the movable parts instead of being surface outwards projecting members as in the latter. The cited document also fails to describe a simplified solution for a camshaft as is described in the present invention. Further, in
FIG. 1
pin
5
, roller
6
and pin
22
, all keep a fixed 90° angle respect of the driving axis but, due to the movement of the cam groove
10
and the cam
21
, when these rotate the engagement angle changes and then the whole mechanism would get jammed. Therefore it seems that the mechanism will never be able to work.
U.S. Pat. No. 1,181,463 describes an engine in which the power of a reciprocal piston is to be transmitted directly to a shaft extending parallel with the piston rod and without the use of intermediate cranks.
FIG. 2
shows that the drum L is provided with an exterior circumferential cam M formed by a pair of radial projecting ribs, the adjacent faces of which are oppositely inclined or beveled. Each piston rod cross head F is provided with a pin of anti-friction contact rolls I, J and the ribs of the cam M is such that the roll J will continuously contact with the surface of the cam adjacent the end A of the frame while the roller I similarly contacts continuously with the cam surface adjacent the frame end A, being the diameter of the roller J less than the width of the cam way or groove in which it moves. As may be clearly seen, the path to which the rollers are constrained to, form a line path and not a surface as in the present invention. The cam groove of
FIGS. 1
,
2
and
3
of the mentioned patent shows four length portions with a different track shape in each portion, one for each step of the well known four-step explosion motor. Therefore, this track design may not be used in other motors with different number of steps. However, in the present invention the tracks are parallel and straight, and therefore the present invention may be used in a four step, two step or Diesel motor with no changes.
U.S. Pat. No. 1,545,925 describes an internal combustion engine having a cylinder with an air passage surrounding it, a piston slidable within the cylinder, a reciprocating cylinder driven by the piston, means whereby the air may be compressed in the reciprocating cylinder, means whereby the air may be forced around the cylinder for cooling it, means whereby power may be taken from the reciprocating cylinder, wherein these last means include a rotatable cylinder having closed grooves in its surface and pins carried by the reciprocating cylinder which project into the grooves. In the invention of the mentioned patent, power is transmitted by air which pushes piston
20
(see
FIG. 1
) and also cools the cylinder. In the present invention, however, power is transmitted by mechanical means. The mentioned patent also teaches away from the present invention because the cams
21
and
22
(
FIG. 1
) and cams
27
and
28
(
FIG. 3
) show crossing grooves instead of parallel or congruent track surfaces.
U.S. Pat. No. 1,628,100 shows an engine that converts reciprocating movement into rational motion by means of an ondulating track.
FIG. 6
shows the cylinders
4
and the pistons
5
, either of which may rotate around the center axle or else the cylinders are fixed and the axle rotates. The ondulating track
2
in
FIG. 6
follows a different shape compared to the one described in the present invention and does not offer the favorable features of the one described in the present document.
U.S. Pat. No. 1,799,772 describes an engine including a plurality of cylinders arranged in pairs, a pair of pistons for each pair of cylinders, a common piston rod for each pair of pistons, a power shaft, means for operating the shaft from the rods, wherein the means comprise a stator member and a rotor member, each of which have spiral internal grooves, heads on the rods engaging the grooves, and means for giving an expansive fluid impact to each piston at its outward limit of travel for forcing the same inward for operating the power shaft. However, the principle for transforming reciprocating movement into circular motion of the invention described in the mentioned patent is totally different from the way the present invention achieves this conversion.
U.S. Pat. No. 2,274,097 reveals a crankless engine for converting reciprocating m
Crowell & Moring LLP
McMahon Marguerite
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