Low stress engine for converting motion between reciprocating and rotational motion

To boost RPM and to minimize the back and forth transfer of kinetic energy between a crank and a connector/reciprocating member in mechanisms having a stroke that is four times the crankpin offset, a connector which attaches the reciprocating member to the crank is weighted with counterweights to produce an effective connector center of mass at a location on the connector that, while rotating around the crankpin defines a motion perpendicular to the oscillation of the reciprocating member such that the resulting translational inertia of the connector is equal to but perpendicular and ninety degrees out of phase with the translational inertia of the reciprocating member so that their combined kinetic energy is constant, thus resulting in a zero transfer in energy between the crank and the connector/reciprocating member through each revolution unless external force is applied to the crank or to the reciprocating member.

BACKGROUND OF THE INVENTION 
This invention relates to machines having a reciprocating member that is 
coupled to a rotatable member and more particularly to the type of machine 
in which the rotatable member is connected to the reciprocating member in 
such a way as to produce a stroke that is four times the crankpin offset. 
Such machines include one or more reciprocating members that drive a 
crankshaft through a connecting rod or other connector and/or a crankshaft 
that drives one or more reciprocating members through a connecting rod 
and/or other connector. Such machines may transfer kinetic energy back and 
forth between the crank and the reciprocating member or members. Examples 
of types of machines that may have a rotatable member connected to the 
reciprocating member in such a way as to produce a stroke that is four 
times the crankpin offset are engines, pumps, compressors and mechanisms 
that convert rotary motion to reciprocating motion and vice versa. 
To provide kinetic energy and to minimize vibrations, these mechanisms 
utilize flywheels and/or a number of reciprocating members to minimize 
fluctuations in the angular velocity of the crank. In the case of a single 
piston engine, making the flywheel larger reduces the change in angular 
velocity of the crank at the top of the stroke when the piston is 
essentially not moving compared to near midstroke when the piston reaches 
its maximum speed. Multiple piston engines can space the angle between 
pistons do not only balance or partially balance the momentums of the 
pistons but to also minimize changes in the angular momentum of the crank. 
Both methods require a constant transfer of energy sack and forth from the 
crankpin to the connecting rod or connector. This results in large forces 
and friction between the crankpin and the connecting rod or connector at 
higher RPMs (revolutions per minute). 
In those engines and motion converting mechanisms that have a stroke that 
is four times the crankpin offset and utilize connectors instead of 
connecting rods, the transfer of energy back and forth between the 
crankpin and the reciprocating member is even further limiting than just 
large forces and resulting friction. At the top part of the stroke and at 
the bottom part of the stroke, the energy is transferred from the crankpin 
through the connector to the reciprocating member and vice versa. However, 
this does not occur through a portion of midstroke where there is a second 
degree of freedom that partially uncouples the primary interface from the 
crankpin through the connector to the reciprocating member. The energy 
must be transferred by an intermittent secondary interface. 
The secondary interface between the crank and the reciprocating member 
disclosed in U.S. Pat. No. 4,658,768 issued to Douglas T. Carson on Apr. 
21, 1987, for ENGINE and the secondary interface between the connector and 
the housing as disclosed in U.S. Pat. No. 4,932,373 issued to Douglas T. 
Carson on Jun. 12, 1990, for MOTION CONVERTING MECHANISM, the disclosures 
of which are incorporated herein by reference eliminate the second degree 
of freedom through midstroke. 
The forces through this center portion of the stroke are much less than 
they are in other portions of the stroke, especially if the combustion 
stroke of an engine where the force from the piston drops off rapidly as 
the piston moves away from the top of the stroke. Likewise, forces climb 
rapidly during compression in engines, pumps, and compressors as the 
piston moves towards the top of the stroke. Because of this, the design of 
the intermittent secondary interface can generally be much less rugged 
than that of the primary interface as taught in U.S. Pat. 4,932,373 issued 
to Douglas T. Carson on Jun. 12, 1990. This is applicable for low and 
medium RPM machines but would require an ever increasing larger and more 
rugged secondary interface as the higher RPMs are achieved. 
The primary interface which is designed to withstand large forces such as 
those resulting from combustion and compression can also withstand those 
forces that occur at the higher RPM machines where the reciprocating 
member is rapidly slowing down, changing direction, and then speeding up 
again. This is not typical of the secondary interface, at higher RPMs, as 
the force necessary to transfer energy back and forth from the crankpin to 
the reciprocating member approaches the external forces encountered by the 
primary interface during compression and combustion. 
The prior art motion converting mechanism have several disadvantages, such 
as for example: (1) they restrict the upper limit on RPM and/or demand a 
larger, more rugged, and more costly secondary interface; (2) the 
resulting friction encountered by the secondary interface is excessively 
high; (3) the energy transferred back and forth between the crank and the 
connector/reciprocating mechanism results in momentary fluctuations in 
crankshaft RPM where the RPM is higher at the ends of the stroke than 
through midstroke; and (4) they require additional moving components, as 
described in U.S. Pat. Nos. 4,658,768 and 4,932,373 (see above), other 
than the basic unit consisting of one crank assembly, one connector and 
one reciprocating member to fully balance the machine. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the invention to provide a novel machine 
having a reciprocating member coupled to a rotary member. 
It is a further object of the invention to provide a machine in which the 
reciprocating member is coupled to the rotary member by a connector to 
reduce machine size. 
It is a still further object of the invention to provide a machine in which 
the reciprocating member is coupled to the rotary member by a connector to 
reduce vibrations. 
It is a still further object of the invention to provide a machine in which 
the reciprocating member is coupled to the rotary member by a special 
connector that includes connector counterweights resulting in a connector 
of size, mass and dimension reduce and/or eliminate the transfer of energy 
back and forth from the crank to the reciprocating member throughout the 
stroke. 
It is a still further object of the invention to provide a machine that 
includes a reciprocating member coupled to a rotary member by a special 
connector with connector counterweights and also incorporates an 
intermittent secondary interface to insure continuity of reciprocating 
member movement through the center of each stroke. 
It is a still further object of the invention to provide a machine that 
includes a reciprocating member coupled to a rotary member by a special 
connector with connector counterweights and also includes an intermittent 
secondary interface between the crank and the reciprocating member to 
insure continuity of reciprocating member movement through the center of 
each stroke. 
It is a still further object of the invention to provide a machine that 
includes a reciprocating member coupled to a rotary member by a special 
connector With connector counterweights and also includes an intermittent 
secondary interface between the connector and the housing to insure 
continuity of reciprocating member movement through the center of each 
stroke. 
It is a still further object of the invention to provide a machine in which 
the reciprocating member is coupled to the rotary member by a special 
connector with connector counterweights resulting in a connector of size, 
mass, and dimensions to reduce and/or eliminate inertia forces on the 
secondary interface. 
It is a still further object of the invention to provide machine in which 
the reciprocating member is coupled to the rotary member by a special 
connector with connector counterweights resulting in a connector of size, 
mass and dimension to limit the forces encountered by the secondary 
interface to only the external for encountered by the reciprocating member 
regardless of RPM. 
It is still further object of the invention to provide a machine in which 
the reciprocating member is coupled to the rotary member by a special 
connector with connector counterweights resulting in a connector of size, 
mass and dimension to minimize the need of a secondary interface for 
applications where the reciprocating member encounters external forces 
only at the ends of the stroke. 
It is a still further object of the invention to provide a machine in which 
the reciprocating member is coupled to the rotary member by a special 
connector with connector counterweights resulting in a connector of size, 
mass and dimension such that the combined inertia forces of the 
reciprocating member, the connector and the crank with the crank 
counterweights balance. 
It is a still further object of the invention to provide a machine in which 
the reciprocating member is coupled to the rotary member by a connector 
with connector counterweights resulting in a connector of size, mass and 
dimension such that the machine can be fully balanced with just three 
moving parts: the crank assembly with crank counterweights, the 
reciprocating member and the connector with connector counterweights. 
It is a still further object of the invention to provide a reciprocating 
piston engine in which the crank undergoes less stress in maintaining a 
reciprocating motion for the piston(s). 
It is a still further object of the invention to provide high RPM 
reciprocating piston engine in which a primary mechanism is utilized to 
transfer the larger forces/lower velocities encountered by the 
reciprocating member to the crank and in which, in addition, an 
intermittent secondary interface is utilized to transfer the smaller 
forces/higher velocities encountered by the reciprocating member to the 
crank. 
It is a still further object of the invention to provide reciprocating 
piston engines, pumps, compressors and various other reciprocating 
mechanisms that are economical in construction. 
It is a still further object of the invention to provide a reciprocating 
piston engine with a connector between the reciprocating member and the 
crank that increases maximum fuel burn time per revolution for diesel 
engines. 
In accordance with the above and further objects of the invention, a 
reciprocating member confined to reciprocation by a housing is attached to 
a crankpin of a rotatable crankshaft by a connector. The connector: (1) 
includes connector counterweights; (2) has a predetermined special size, 
mass and dimension; (3) rotates in an angular direction opposite that of 
the crankshaft; (4) has a stroke four times the crankpin offset in an axis 
of reciprocation; (5) has a motion of the center of mass of the connector 
that is an elliptical path with its major axis in a direction 
perpendicular to the axis of reciprocation; and (6) has a mass equal to 
that of the reciprocating member as the major axis approaches a straight 
line. The machine may include a secondary interface between the crank and 
the reciprocating member or between the connector and the housing. 
The crank assembly has counterweights that oppose the inertia force 
(inertia vector) of the reciprocating member in the axis of reciprocation 
and oppose the inertia force (inertia vector) of the connector in the axis 
perpendicular to the axis of reciprocation. 
The reciprocating member is confined to reciprocating motion by the walls 
of a housing that houses the crank, the connector and the rod assembly 
portion of the reciprocating member. The rod assembly in turn confines the 
center of rotation of the connector to reciprocating motion The housing 
walls thus restrict the rod assembly and the center of connector rotation 
to reciprocating motion in which the resulting velocity is equal to twice 
the velocity of the crankpin center in the direction of reciprocation. 
The center of connector rotation which is confined to reciprocation is a 
distance of one crankpin radius from the crankpin center. To eliminate the 
transfer of energy back and forth between the crankpin and the 
reciprocating member, the novel connector has a mass equal to the 
reciprocating member and a center of mass located one crankpin radius from 
the center of the crankpin in the direction opposite that of the center of 
connector rotation. The center of connector rotation revolves around the 
crankpin while it reciprocates within the reciprocating member as the 
connector's center of mass revolves around the crankpin while moving in a 
straight line perpendicular to the direction of reciprocation. 
The distance between the connector's center of rotation and its center of 
mass is twice the crankpin offset. The hole in the connector that receives 
the crankpin is located centrally between the connector's center of 
rotation and its center of mass. As the crankpin rotates the connector's 
center of rotation reciprocates within the reciprocating member while 
revolving around the crankpin with an angular velocity that is equal and 
opposite the angular velocity of the crankpin. 
The angular velocity of the connector's center of mass is the same as the 
connector's center of rotation and its motion is perpendicular to that of 
the connector's center of rotation. The connector's center of rotation 
defines the velocity and energy of the reciprocating member in the 
direction of reciprocation while the connector's center of mass defines 
the velocity and energy of the connector in a direction perpendicular to 
the direction of reciprocation and ninety degrees out of phase with the 
reciprocating member. 
When the connector's center of rotation is at its maximum velocity, its 
center of mass has a zero velocity and vice versa. The combined energy of 
the reciprocating member moving in a direction of reciprocation and that 
energy of the connector which, while revolving around the crankpin, is 
moving in a direction perpendicular to reciprocation are thus constant. 
The translational inertia force (inertia vector) of the reciprocating 
member in the direction of reciprocation and also the translational 
inertia force (inertia vector) of the connector in the direction 
perpendicular to the direction of reciprocation are ninety degrees out of 
phase and are opposed by crank counterweights positioned on the crank 
assembly opposite the crankpin. The crank counterweights oppose the 
inertia force (inertia vector) of the reciprocating member at the ends of 
the stroke, the connector inertia force (inertia vector) a midstroke, and 
the combined inertia forces (inertia vector) of the reciprocating member 
and the connector through the rest of the stroke. The machine may be fully 
balanced with only three moving parts: the crank assembly with crank 
counterweights, the special connector with connector counterweights and 
the reciprocating member. 
In another embodiment, the center of connector rotation, which is confined 
to reciprocation, is a distance of one crankpin radius from the crankpin 
center. To eliminate the transfer of energy back and forth between the 
crankpin and the reciprocating member, the novel connector has a mass 
equal to the mass of the reciprocating member times one crankpin radius 
divided by the distance from the connector's center of mass to the 
crankpin center where the crankpin center is on a line between the center 
of connector rotation and the connector's center of mass. The center of 
connector rotation revolves around the crankpin while it reciprocates 
within the reciprocating member as the connector's center of mass revolves 
around the crankpin while moving in an ellipse with a major axis 
perpendicular to the direction of reciprocation. 
The angular velocity of the connector's center of mass is the same as the 
connector's center of rotation and its motion is primarily perpendicular 
to that of the connector's center of rotation. The connector's center of 
rotation defines the velocity and energy of the reciprocating member in 
the direction of reciprocation while the connector's center of mass 
defines the velocity and energy of the connector in th form of an ellipse 
with the major axis in a direction perpendicular to the direction of 
reciprocation and ninety degrees out of phase with the reciprocating 
member. 
When the connector's center of rotation is at its maximum velocity, its 
center of mass is at its minimum velocity with a zero component in the 
direction perpendicular to the axis of reciprocation and when the 
connector's center of mass is at its maximum velocity, its center of 
rotation has a zero velocity. The combined energy of the reciprocating 
member and of the connector are constant. 
The combined translational inertia forces (inertia vector) of the 
reciprocating member in the direction of reciprocation and the component 
inertia force (inertia vector) of the connector in the same direction and 
the component translational inertia force (inertia vector) of the 
connector in the direction perpendicular to the direction of reciprocation 
are ninety degrees out of phase and are opposed by the crank 
counterweights positioned on the crank assembly opposite the crankpin. The 
crank counterweights oppose the inertia force (inertia vector) of the 
connector at midstroke and the combined inertia forces (inertia vector) of 
the reciprocating member and the connector at the ends of the strokes and 
through the rest of the stroke. The machine may be fully balanced with 
only three moving parts: the crank assembly with crank counterweights, the 
special connector with connector counterweights and the reciprocating 
member. 
In one embodiment, a two cycle engine uses a double acting piston as part 
of the reciprocating member, a connector with connector counterweights 
resulting in a connector of mass, size and dimension to eliminate the 
transfer of energy back and forth between the crank and the reciprocating 
member and a crank assembly with counterweights to produce two power 
strokes per revolution with substantially no vibrations from inertia 
forces (inertia vectors). 
This motion converting mechanism has several advantages, such as: (1) it is 
economical, particularly in two cycle diesel engines since large number of 
cylinders are not required to balance the inertia forces (inertia 
vectors); (2) it provides reduced size in engines, pumps compressors and 
other rotary to reciprocating mechanisms that are balanced so as to be 
relatively vibration free; (3) it provides a more economical mechanism due 
to less continuous crank stress and corresponding friction; (4) it allows 
higher RPMs without requiring a correspondingly larger and more rugged 
secondary interface; (5) it provides a simpler method of balancing all 
inertia forced (inertia vectors) for engines, pumps, compressors and 
various other mechanisms that convert rotary motion to reciprocating 
motion and vice versa by requiring only three moving parts: one crank 
assembly, one connector and one reciprocating member.

DETAILED DESCRIPTION 
In FIG. 1 there is shown a partly exploded, fragmentary view of a machine 8 
having a reciprocating member assembly 10, a crank assembly 12, and a 
connector 14. The crank assembly 12, as shown in FIG. 1, includes crank 
journals 32A and 32B, a crankpin 34 which is integral with crank journal 
32A and fastened to crank journal 32B, crank counterweights 62A and 62B 
and flywheel 64. The reciprocating member assembly 10 includes rod 
connecting link 22, reciprocating piston portion 24 and the rod assembly 
20. The rod assembly 20 includes portions 21A and 21B which are fastened 
together with bolts 26A and 26B (not shown) and bearing surfaces 28A and 
28B on surfaces where rod assembly 20 receives cylindrical portion 40 
connector 14. 
To transfer force between and to control the reciprocating member assembly 
10 and the crank assembly 12, the connector 14 includes a hole 46 with 
bearing surfaces that receive crankpin 34, a cylindrical portion 40 that 
is received my the hole in the rod assembly 20 of reciprocating member 
assembly 10, connector counterweights 42A and 42B and secondary interfaces 
44A (not shown) and 44B. The connector 14 is thus rotatably mounted at 
hole 46 to the crankpin 34 and also rotatably attached at cylindrical 
portion 40 to the rod assembly 20 which in addition constrains the 
cylindrical portion 40 to reciprocating motion since the rod assembly 20 
is confined to reciprocation by rod constraining surfaces (not shown in 
FIG. 1). With the secondary interfaces 44A and 44B, the primary mechanism 
is utilized to transfer the larger forces/lower velocities encountered by 
the reciprocating member to the crank and the intermittent secondary 
interfaces are utilized to transfer the smaller forces/higher velocities 
encountered by the reciprocating member to the crank. 
The distance from the center (axis) of cylindrical portion 40 to the center 
(axis) of the hole 46 of the connector 14 that receives the crankpin 34 is 
equal to the distance from the center (axis) of the crank assembly 12 to 
the center (axis) of the crankpin 34, hereafter referred to as the 
crankpin offset or as the radius of crank rotation. The connector 
counterweights 42A and 42B are sized so that the resulting mass of the 
connector 14 is substantially the same as the mass of the reciprocating 
member assembly 10 and the center (axis) of the mass of the connector 14 
is located at a distance equal to and in a direction opposite the center 
of the hole 46 receiving the crankpin 34 as is the center of the 
cylindrical portion 40. 
With this construction, the connector 14 rotates around the crankpin 34 
while the cylindrical portion 40 of the connector 14 rotates within the 
rod assembly 20 as its center reciprocates on the axis of reciprocation. 
The center of mass of connector 14 rotates around the crankpin 34 while it 
oscillates on an axis perpendicular to the axis on which the rod assembly 
20 and the center of cylindrical portion 40 reciprocate. 
The crank assembly 12 has counterweights that oppose the inertia force 
(inertia vector) of the reciprocating member assembly 10 along its axis of 
reciprocation and oppose the inertia force (inertia vector) of the 
connector 14 in the axis perpendicular to the axis of reciprocation. The 
translational inertia force (inertia vector) of the reciprocating member 
assembly 10 in the direction of reciprocation and also the translational 
inertia force (inertia vector) of the connector 14 in the direction 
perpendicular to the direction of reciprocation are ninety degrees out of 
phase and are opposed by crank counterweights 62A and 62B positioned on 
the crank assembly 12 opposite the crank pin 34. 
The crank counterweights 62A and 62B oppose the inertia force (inertia 
vector) of the reciprocating member at the end of the stroke, the 
connector inertia force (inertia vector) at midstroke and the combined 
inertia forces (inertia vector) of the reciprocating member and the 
connector through the rest of the stroke. 
The connector 14 incorporates intermittent secondary interfaces 44A and 44B 
to insure continuity of reciprocating member movement through the center 
of each stroke and incorporates counterweights 42A and 42B that cause the 
connector to have a size, mass and dimension that: (1) reduce and/or 
eliminate the transfer of energy back and forth from the crank to the 
reciprocating member throughout the stroke; (2) reduce and/or eliminate 
inertia forces on the secondary interface; (3) limit the forces 
encountered by the secondary interface to only the external forces 
encountered by the reciprocating member regardless of RPM; (4) minimize 
the need of a secondary interface for applications where the reciprocating 
member encounters external forces only at the ends of the stroke; (5) 
enable the combined inertia forces of the reciprocating member the 
connector and the crank to balance; (6) enable the machine to be fully 
balanced with just three moving parts: the crank assembly with crank 
counterweights, the reciprocating member and the connector with connector 
counterweights; (7) increase maximum fuel burn time per revolution for 
diesel engines; and (8) reduce stress on the crank in maintaining a 
reciprocating motion for the piston or pistons. 
The relationship of the reciprocating member assembly 10 when it is at the 
top of the stroke with the axes in the Z direction), hereafter referred to 
as the centers, of crank 12, crankpin 34, and cylindrical portion 40 of 
connector 14 with respect to the connector 14 and crank assembly 12 is 
illustrated by the projection onto a plane having an X axis 53 (the axis 
of reciprocation for reciprocating member assembly 10, rod assembly 20, 
and the center of cylindrical portion 40) and a Y axis 55. The orientation 
of the X and Y axis in FIG. 1 has been rotated from conventional to be 
consistent with the XY orientation in FIGS. 2 and 8 which is conventional. 
In this projection, the center of crank rotation is projected to point 50 
and is hereafter referred to as crank center 50 or the center of crank 
rotation 50. The center of crankpin 34, hereafter referred to as crankpin 
center 52, revolves around the center of crank rotation 50 as projected on 
circle 52 where points 52A, 52B, 52C and 52D are the top of the stroke, 
midstroke where the reciprocating components are moving away from the top 
of the stroke, the bottom of the stroke and midstroke where the 
reciprocating components are moving towards the top of the stroke 
respectively. 
The motion of the center of cylindrical portion 40 of the connector 14, 
hereafter referred to as the center of connector rotation 54, is projected 
as line 54 which is on X axis 53 and includes points 54A, 50, 54C and 50 
which are again the top of the stroke, midstroke, the bottom of the stroke 
and midstroke respectively. The motion of the center of mass of connector 
14, hereafter referred to as the connector center of mass 56, is projected 
as line 56 which is on Y axis 55. The motion of the connector center of 
mass 56 along Y axis 55 includes points 50 (or 56A), 56B, 50 and 56D which 
are again the top th stroke, midstroke the bottom of the stroke and 
midstroke. Both the center of connector rotation 54 and the connector 
center of mass 56 substantially pass through point 50 which is the 
intersection of X axis 53 and Y axis 55 and is the center of crank 
rotation 50. The center of connector rotation 54 and the connector center 
of mass 56 substantially coincides with the center of crank rotation 50 at 
midstroke and at the ends of the stroke respectively. 
The reciprocating piston portion 24 may be a piston of any of the types 
used in an internal or external combustion engine, a pump or a compressor 
or it may be any other type of reciprocating member such as one that may 
be used in a stitching mechanism or an automated punch. Moreover while one 
piston is shown in FIG. 1, a plurality of pistons or other reciprocated 
members may be moved instead. They maybe mounted in different locations 
and ways to the rod or rods, such as, with one on each side of rod 
assembly 20 or only on one side and may be integral with the rod or 
separate from the rod. Generally, the piston portion, 24 is representative 
of any device or devices that requires back and forth motion and requires 
rotary motion mechanism to drive it or to be driven by it. 
The rod assembly 20, the rod connecting link 22, and the reciprocating 
piston portion 24 may all be integrally formed so as to be of unit 
construction or be separate and fastened in a variety of ways. If 
integral, the rod assembly 20 may be shaped as a right angle 
parallolepiped with a diameter the same a the piston portion 24. The rod 
assembly 20 may have a different diameter or have rectangular sides. 
The crank assembly 12 is constructed with crankpin 34 solid to crank 
journal 32A After the connector 14 is positioned on the crankpin 34, the 
crank journal 32B is assembled and fastened to the crankpin 34. The 
crankpin 34 and crank journal 32B have slots 38 A and B and 36A and B 
respectively that receive pins (not shown) to properly orient crank 
journal 32B with crank journal 32A. Any other suitable means may be used 
to fasten crank journal 32B to crankpin 34 and other common methods of 
crank construction and assembly including unit construction may be used 
provided they are coordinated with the construction of connector 14 and 
rod assembly 20 and can be assembled. 
In the embodiment of FIG. 1, the connector 14 includes the cylindrical 
portion 40, the connector counterweights 42A and 42B adjacent to the 
cylindrical portion 40, and the connector side secondary interfaces 44A 
(not shown) and 44B adjacent to the connector counterweights 42A and 42B 
respectively. Various other connector constructions are possible including 
connector side secondary interfaces 44A and 44B being between the 
cylindrical portion 40 and the connector counterweights 42A and 42B. The 
connector side secondary interfaces could also be central with cylindrical 
portion 46 on both sides of the secondary interfaces 44A and 44B with 
counterweights 42A and 42B then adjacent to the two cylindrical portions. 
Another embodiment includes connector 14 without the connector side 
secondary interfaces 44A and 44B. This embodiment is representative of a 
machine without a secondary interface or with a secondary interface 
between the crank 12 and the rod assembly 20. 
In still another embodiment, the crankpin 34 and the connector 14 are 
integral with the crankpin 34 being rotatably attached to crank journal 
32A and 32B, in which case rotating inside the crank journals. The 
distance from the center of the crank journals 32A and 32B to the holes in 
the crank journals that receives crankpin 34 is still the crankpin offset 
and is equal to the distance from the center of crankpin 34 to the center 
of cylindrical portion 40 of the connector 14. 
In FIGS. 2-7 here are shown, in a series of simplified, developed views, in 
section, the principal parts of the machine 8 including the reciprocating 
member assembly 10, the housing 16, the crankpin 34, the crank journals 
32A and 32B (not shown) and the cylindrical portion 40 of connector 14 
illustrating the operation of the embodiment of FIG. 1. The housing 16 
includes rod assembly restraining surfaces 17 and 18 which confine rod 
assembly 20 (FIG. 1) of reciprocating member assembly 10 to reciprocating 
motion. 
The rod constraining surfaces 17 and 18 in the housing 16 and corresponding 
surfaces on rod assembly 20 resist the side thrust forces that are 
encountered on rod assembly 20. In the preferred embodiment, these 
surfaces receive forced oil lubrication and should be significantly 
removed from the normal heat build up as found in combustion engines. If 
the rod constraining surfaces 17 and 18 are an extension of the cylinder 
wall then the fit between the piston and the cylinder walls would 
generally be slightly looser than the fit between rod assembly 20 and rod 
constraining surfaces 17 and 18 to allow for thermal expansion. However, 
this would be minimized with ceramics or thermal barrier coats. 
The projection of the center of crank rotation, the crankpin center, the 
center of the cylindrical portion and the center of mass from FIG. 1 are 
further illustrated in FIGS. 2-7 and in FIGS. 8a-8f FIG. 2 illustrates 
motion converting mechanism 8 at the top of the stroke with center 52A of 
crankpin 34 and the center of connector rotation 54A of cylindrical 
portion 40 located on the positive side of the X axis as in FIG. 1. At the 
top of the stroke, the connector center of mass 56A of connector 14 
coincides with the center of crank rotation 50. 
For convenience, the top of the stroke is defined as 0 degrees where 
crankpin center 52A of crankpin 34 and the center of connector rotation 
54A of cylindrical portion 40 of connector 14 are both located on the X 
axis 53 on its positive side. FIGS. 3-7 and 8a-8f illustrate motion 
converting mechanism 8 for 30 degrees, 60 degrees, 90 degrees, 180 degrees 
and 270 degrees respectively. FIGS. 8a-8f illustrate the centers only from 
FIGS. 2-7 by showing the center of crank rotation, the crankpin center, 
the center of connector rotation and the connector center of mass for 0 
degrees, 30 degrees 60 degrees, 90 degrees, 180 degrees and 270 degrees. 
In FIGS. 1 and 2, at the top of the stroke, the center of crank rotation 50 
of crank assembly 12, the crankpin center 52A of crankpin 34 and the 
center of connector rotation 54A of cylindrical portion 40 of connector 14 
are all substantially on the axis of reciprocation (X axis) 53. At the top 
of the stroke, the connector center of mass 56A of connector 14 
substantially coincides with the center of crank rotation 50. 
In FIG. 5 at midstroke, the center of crank rotation, 50 the crankpin 
center 52B and the connector center of mass 56B are substantially on line 
55 (Y axis) which is perpendicular to the axis of reciprocation 53 and 
intersecting it at the center of crank rotation 50. At midstroke, the 
center of connector rotation 54B and the center of crank rotation 50 
substantially coincide. Note that the crankpin center, the center of 
connector rotation and the connector center of mass will be referred to as 
52, 54 and 56 respectively unless a specific angle is referenced such as 0 
degrees at the top of the stroke where they are referred to as 52A, 54A 
and 56A respectively. 
Because the crank center (center of crank rotation) 50 and the center of 
connector rotation 54 coincide at midstroke, the distance from the 
crankpin center 52 to the center of connector rotation 54 is equal to the 
distance from crank center 50 to crankpin center 52 and thus equal to the 
crankpin offset. It also follows that the distance from crank center 50 to 
the center of connector rotation 54 at the top of the stroke is equal to 
the distance from the crank center 50 to crankpin center 52 plus the 
distance from crankpin center 52 to the center of connector rotation 54 or 
twice the crankpin offset. The stroke is thus substantially four times the 
crankpin offset. 
The basic structure and operation of the primary mechanism (crank, 
crankpin, connector, rod assembly and housing walls) of the machine is 
similar to that described in U.S. Pat. No. 4,658,768. The basic structure 
and operation of the secondary interface between the crank and the rod 
assembly or between the connector and the housing is similar to that 
described in U.S. Pat. No. 4,658,768 and U.S. Pat. No. 4,932,373 
respectively. Further description of the parts of the basic machine with a 
stroke four times the crankpin offset including the primary mechanism and 
the secondary interfaces between the crank and the rod assembly and 
between the connector and the housing are provided in these patents with 
reference to similar drawings and technology. 
Since the crank center 50 and the connector center of mass 56 coincide at 
the top and the bottom of the stroke, it follows that the distance from 
crankpin center 52 to the connector center of mass 56 is equal to the 
distance from crank center 50 to crankpin center 52 and thus equal to the 
crankpin offset. It also follows that the distance from the crank center 
50 to the connector center mass 56 a midstroke is equal to the distance 
from crank center 50 to crankpin center 52 plus the distance from crankpin 
center 52 to the connector center mass 56 or twice the distance from crank 
center 50 to crankpin center 52 or twice the crankpin offset. The movement 
of the connector center of mass 56 is thus substantially four time the 
crankpin offset perpendicular to the direction of rod assembly 
reciprocation. 
The motion of crankpin center 52 can be broken down into a component motion 
in the X axis or the direction of rod assembly reciprocation and a 
component of motion in the Y axis or in the direction perpendicular to the 
axis of reciprocation. The center of connector rotation 54 is confined to 
motion along the axis of reciprocation 53. Also, as best seen in FIGS. 8a 
and 8b at 30 degrees and at 60 degrees, the angle between the line 
connecting crank center 50 to crankpin 52 and the line connecting the 
center of connector rotation 54 and crankpin center 52 is equal to 
substantially twice the angle between the line connecting crankpin center 
52 to crank center 50 and the line which is perpendicular to the axis of 
reciprocation 53 and which passes through crank center 50. 
Because of this relationship, as the crankpin center 52 rotates 
counterclockwise, the center of connector rotation 54 reciprocates on the 
axis of reciprocation 53 while rotating clockwise relative to crankpin 
center 52. If crankpin center 52 rotates in the clockwise direction, the 
center of connector rotation 54 reciprocates on the axis of reciprocation 
53 while rotating counterclockwise relative to crankpin center 52. The 
angular velocity of the connector 14 is equal and opposite the angular 
velocity of crank assembly 12. The center of connector rotation 54 has an 
angular velocity relative to crankpin 34 that is opposite and twice that 
of the angular velocity of crankpin 34 relative to crank center 50. Also, 
the motion and velocity of the center of connector rotation 54 is 
substantially twice the component of motion and velocity of crankpin 
center 52 in a direction of rod assembly reciprocation. 
The movement and velocity of the center of connector rotation 54 is twice 
that of the crankpin center 52 in the direction of reciprocation. This 
relationship is very exacting at the top of the stroke and the bottom the 
stroke especially when the crankpin is approaching the axis of 
reciprocation 53. However, as the crankpin center 52 approaches midstroke, 
the relationship for the primary mechanism without a secondary interface 
becomes less defined. 
As crankpin center 52 approaches midstroke, the angle between the axis of 
reciprocation 53 and the line connecting crank center 50 and crankpin 
center 52 approaches 90 degrees and the sine of that angle approaches 1. 
Since the distance from crankpin center 52 to the center of connector 
rotation 54 is equal to the distance from crank center 50 to the crankpin 
center 52, the sine of the angle between the axis of reciprocation 53 and 
the line connecting crankpin center 52 to the center of connector rotation 
54 approaches 1. However, the sines of angles between 88 degrees and 92 
degrees range from 0.9994 to 1 and are thus approaching 1. Meanwhile the 
cosines of the same angles are changing significantly. 
Because of this relationship where the change in the sine of the angle is 
very small compared to the change in the cosine of the angle, the center 
of connector rotation 54 several could easily be several degrees or even 
more ahead of or behind the crankpin center 52 at midstroke. Further, 
since the set of angles with sines essentially approaching 1 include 
angles from about 85 degrees to 95 degrees, the center of connector 
rotation 54 could run substantially ahead or behind its theoretical 
position relative to the crankpin center 52 especially if reciprocating 
member assembly 10 is subjected to large forces that are in the direction 
of reciprocation through that portion of midstroke. 
In addition, a second degree of freedom exists at exact midstroke when the 
center of connector rotation 54 coincides with the crank center 50. At 
exact midstroke, it is possible for crank assembly 12 and connector 14 to 
rotate with the same angular velocity in the same direction resulting in 
zero reciprocation motion and velocity for the center of connector 
rotation 54 and reciprocating member assembly 10. 
A secondary interface to augment the primary mechanism (crank, crankpin, 
connector, rod assembly and housing walls) can eliminate the second degree 
of freedom and the possibility of the reciprocating member running ahead 
or falling behind its theoretical position relative to the crank U.S. Pat. 
Nos. 4,658,768, 4,543,919 and 4,485,769 describe a secondary interface 
between the crank assembly and the rod assembly and U S. Pat. No. 
4,932,373 describes a secondary interface between the connector and the 
housing walls the disclosures of which are incorporated herein by 
reference. 
In FIGS. 9 and 10, a secondary interface between the connector and the 
housing walls is shown at midstroke where the connector side secondary 
interface portions 44C and 44D are engaged with housing side secondary 
interface portions 72A and 72B respectively. Also shown is housing side 
secondary interface portions 72C and 72D which connector side secondary 
interface portions 44C and 44D will engage in the opposite direction of 
reciprocation through midstroke. 
Connector side secondary interface portions 44C and 44D, in FIGS. 9 and 10, 
are confined by housing side secondary interface portions 72A and 72B to a 
motion of zero movement and zero velocity in the direction of 
reciprocation at point on the connector side secondary interface that is 
of equal but opposite distance from the crankpin center 52 (FIG. 1) of 
crankpin 34 (FIG. 1) as is the center of connector rotation 54 (FIG. 1) of 
cylindrical portion 40 (FIG. 1) of the connector. This arrangement 
restricts the motion and velocity of the center of connector rotation 54 
of cylindrical portion 40 to be twice that of the crankpin center 52 of 
crankpin 34 in the direction of reciprocation. This resulting motion and 
velocity is the same and coincides with the motion and velocity of the 
primary mechanism and thus eliminates the second degree of freedom at 
exact midstroke and prevents the reciprocating member from running ahead 
or behind the crank assembly through a predetermined portion of midstroke. 
This mechanism is described in detail in U.S. Pat. No. 4,932,373. 
The secondary interface describe in detail in U.S. Pat. Nos. 4,658,768, 
4,543,919 and 4,485,769 is an interface between the crank and the rod 
assembly. The surfaces of the interface on the crank relative to a point 
on a line extending from the crank center through the crankpin center and 
at a distance twice the crankpin offset from the center of the crank 
impart and restrict motion to surfaces on the rod assembly that is twice 
that of the crank in center in the direction of reciprocation. Some forms 
of these surfaces are cam, cam-follower and gearing. This interface also 
confines the motion and velocity of the rod assembly to twice that of the 
crankpin center in the direction of reciprocation through a predetermined 
portion of midstroke. 
At low to moderate speeds, the reciprocating member will generally 
encounter large forces an low velocities at the top of the stroke and 
smaller forces and higher velocities through midstroke. This would be 
typical of an engine when the piston portion of the reciprocating member 
is at the top of the stroke compressing and burning gases. The forces that 
the reciprocating member encounters during compression and ignition are 
generally many times greater than those forces it encounters as it travels 
through midstroke. This is true for pumps and compressors as well as 
engines where the force encountered by the reciprocating mechanism 
increases rapidly as it approaches the top of the stroke for single acting 
pistons. It is, thus, practical to size the secondary interface to 
encounter considerable smaller loads than the primary member due to the 
nature of the relative size of the forces encountered through midstroke as 
compared to the ends of the stroke. This is described in detail in U.S. 
Pat. No. 4,932 373. 
It is advantageous, as described for rotary to reciprocating mechanisms of 
low to moderate speeds, to design the primary mechanism to transfer the 
large forces encountered at the ends of the stroke and to design the 
secondary interface with only that bulk and strength necessary to transfer 
the smaller forces found through midstroke. However, as speeds increase 
and the effects of inertia forces (inertia vectors) become more prominent, 
the secondary interface encounters ever increasing loads. These forces 
will even exceed those on the primary interface at the higher RPMS. The 
design would generally dictate that the bulk or size of the secondary 
interface should increase which also increases the size, the cost and the 
complexity of such mechanisms. 
However, a novel solution to inertia dictating increased sizing of the 
secondary interface is the addition of connector counterweights that are 
sized and located so as to eliminate and or to reduce loads on the 
secondary interface due to inertia forces (inertia vectors) thus freeing 
the interface to transfer from the reciprocating member to the crank 
assembly only those forces that are encountered by the reciprocating 
portion of the reciprocating member. 
Hereinafter in this specification, inertia forces will be used in 
describing the resistance that moving components offer when their motion 
is being changed even though the term inertia vector better distinguishes 
the vector -ma (m is mass and a is acceleration) from actual forces. 
Connector counterweights 42A and 42B (FIG. 1) are a novel addition to 
connector 14 associated with engines and motion converting mechanisms with 
a stroke that is four times the crankpin offset. They eliminate an 
inherent weakness in the simplified design of the primary mechanism and 
the secondary interface where inertia forces increase and approach or 
exceed those forces associated with loads on the piston or the 
reciprocating portion of the reciprocating member. 
As better described in U.S. Pat. Nos. 4,658,768 and 4,932,373, the primary 
interface is between the crank/crankpin, the connector, the rod assembly 
and the housing with the secondary interface being either between the 
crank and the rod assembly as described in U.S. Pat. No. 4,658,768 or 
between the connector and the housing as described in U.S. Pat. No. 
4,932,373. U.S. Pat. No. 4,932,373 more specifically details that it is 
advantageous to design the primary interface strong enough to handle the 
large forces encountered at either end of the stroke while the secondary 
interface should be designed to handle the lower forces and higher 
velocities associated with midstroke or the center portion of the stroke. 
This is very applicable for low to medium speed mechanisms but must be 
modified for high to very high speed engines and motion convering 
mechanisms. 
As inertia forces increase and start to approach load forces on the 
reciprocating portion 24 of the reciprocating member assembly 10, then the 
necessary size of the secondary interface must increase to handle the 
inertia forces that are now approaching the size of the larger load 
forces. 
One method to handle increased inertia forces on the secondary interface 
resulting from higher RPMs is to increase the size of the secondary 
interface until it approaches or exceeds the size of the primary 
interface. A novel solution is the addition of connector counterweights 
42A and 42B, best shown in FIGS. 1-7 and 8a-8f that are of mass and 
location such that the resulting mass for connector 14 is substantially 
equal to the mass of reciprocating member assembly 10 and the connector 
center of mass 56 for connector 14 is located a distance of one crankpin 
offset in an equal and opposite direction from the center of hole 46 that 
receives crankpin 34 as is the center of connector rotation 54 of 
cylindrical portion 40. Thus connector 14 has a mass that is substantially 
equal to the mass of reciprocating member assembly 10 and connector 14 has 
a connector center of mass 56 that is substantially located a distance 
equal to the crankpin offset from crankpin center 52 and at a distance 
equal to twice the crankpin offset from the center of connector rotation 
54 and is on the same line so that crankpin center 52 is centrally located 
between connector center of mass 56 and the center of connector rotation 
54. 
The negative effect of ever increasing inertia forces at higher RPM on the 
secondary interface can either be removed or reduced with the novel use of 
connector counterweights that remove or reduce the transfer of energy back 
and forth between the crank and the reciprocating member. 
In FIG. 1 mechanism 8 is at the to of the stroke where connector 14 is 
shown with cylindrical portion 40, hole 46 that receives crankpin 34, 
connector counterweights 42A and 42B and the seconday interface portions 
44A (not shown) and 44B. The center of connector rotation of cylindrical 
portion 40 is projected to point 54A, the crankpin center that coincides 
with the center of hole 46 is projected to point 52A, the resulting 
connector center o mass of connector 14 including the addition of special 
connector counterweights 42A and and 42B are projected to point 56A which 
coincides with point 50, and the crank center is projected to point 50. 
All four centers are shown on the axis of reciprocation 53 for the top of 
the stroke. The orientation of the "X" axis 53 and the "Y" axis 55 in FIG. 
1 is oriented to better coincide with the description and orientation used 
in FIGS. 2-7 and respective ones of FIGS. 8a-8f. The "X" axis is referred 
to as the axis of reciprocation in which reciprocating member assembly 10 
is confined to travel and the crankpin center 52, the center of connector 
rotation 54 and the connector center of mass 56 are indicated by subscript 
letters A-F in FIGS. 2-7 and respective ones of FIGS. 8a-8f to show their 
position at various parts of the stroke. 
Since the distance from the connector center of mass 56 is of equal 
distance but in opposite direction from the crankpin center 52 as is the 
center of connector rotation 54 and since the center of connector rotation 
54 is confined to reciprocation on the axis of reciprocation 53, the 
connector center of mass 56 must oscillate along a line 56 which is a 
projection onto the "Y" axis 55 and is perpendicular to the axis of 
reciprocation 53. Further, since the center of connector rotation 54 is 
confined to reciprocation on the axis of reciprocation 53 with zero 
movement and velocity in the direction perpendicular and since the 
connector center of mass 56 is on a line extending from the center of 
connector rotation 54 through crankpin center 52 and at twice the distance 
from the center of connector rotation 54 as is crankpin center 52, the 
movement and velocity of the connector center of mass 56 in the direction 
perpendicular to the axis of reciprocation 53 must be twice that of the 
movement and velocity of crankpin center 52 in the direction perpendicular 
to the axis of reciprocation 53. 
Since the center of connector rotation 54 is confined to a movement and 
velocity on the axis of reciprocation 53 that is twice that of crankpin 
center 52 in the axis of reciprocation 53 and since the distance from the 
connector center of mass 56 to the center of connector rotation 54 is 
twice that from the connector center of mass 56 to crankpin center 52, the 
resulting movement and velocity for the connector center of mass 56 in the 
axis of reciprocation 53 must be zero. Thus, the connector center of mass 
56 oscillates perpendicular to the axis of reciprocation 53 with a travel 
of four times the crankpin offset and with a velocity that is twice the 
velocity of the crankpin center 52 in the direction perpendicular to the 
axis of reciprocation 53. 
The movement and velocity of the connector center of mass 56 relative to 
crank center 50 is perpendicular to and of equal magnitude as the center 
of connector rotation 54 but 90 degrees out of phase. At the top and 
bottom of the stroke, the connector center of mass 56 will be at its 
maximum velocity while the center of connector rotation 54 is at its 
minimum. At midstroke, the connector center of mass 56 is at its minimum 
velocity while the center of connector rotation 54 is at its maximum. 
Both the center of connector rotation 54 and the connector center of mass 
56 oscillate perpendicular to each other through the ax's of crank 
rotation 50. This embodiment results in the connector center of mass 56 of 
connector 14 rotating around crankpin center 52 with an equal but opposite 
angular velocity as does crankpin center 52 around the crank center 50 
while oscillating perpendicular to the axis of reciprocation 53 with a 
velocity that is equal but 90 degrees out of phase with the velocity of 
the center of connector rotation 54 and reciprocating member assembly 10. 
In FIG. 2, at the top of the stroke, the connector center of rotation 54, 
crankpin center 52A, the connector center of mass 56A and crank center 50 
are all shown of the same line which is the axis of reciprocation 53. The 
connector center of mass 56A also coincides with crank center 50 at the 
top of the stroke. The crank center 50 and the center of connector 
rotation 54 are always on the axis of reciprocation while crankpin center 
52 and the connector center of mass 56 pass through the axis of 
reciprocation at the top of the stroke and the bottom of the stroke. 
At the bottom of the stroke in FIG. 6, the connector center of rotation 
54C, the crankpin center 52C, the connector center of mass 56C and crank 
center 50 again all fall on the axis of reciprocation with the connector 
center of mass 56C coinciding with the center of crank rotation 50. At the 
top of the stroke and the bottom of the stroke, the velocity of the 
crankpin center 52 has a component velocity of zero in the axis of 
reciprocation. The velocity of the center of connector rotation 54 is 
twice that of crankpin center 52 in the axis of reciprocation and is thus 
zero at the top of the stroke and at the bottom of the stroke. 
Since the connector center of mass 56 is on a line twice the distance from 
the connector center of rotation 54 as is crankpin 52 and since the 
velocity of the center of connector rotation 54 is zero, the velocity of 
the connector center of mass 56 is twice that of crankpin center 52. The 
velocity of the connector center of mass 56 is thus twice that of the 
crankpin center 52 in a direction perpendicular it to the axis of 
reciprocation. 
At midstroke in one direction of reciprocation as shown in FIG. 5, the 
center of connector rotation 54B, the crankpin center 52B and the 
connector center of mass 56B all fall on a line 55 ("Y" axis) that is 
perpendicular to the axis of reciprocation 53 and passing through the 
center of crank rotation 50 with the center of connector rotation 54B 
coinciding with crank center 50. At midstroke in the other direction of 
reciprocation as shown in FIG. 7, the center of connector rotation 54D, 
the crankpin center 52D and the connector center of mass 56D all fall on 
line 55 ("Y" axis) with the center of connector rotation 54D coinciding 
with crank center 50. 
At midstroke in both directions of reciprocation, the velocity of the 
crankpin center 52 has a component velocity of zero in the direction 
perpendicular of the axis of reciprocation. Since the connector center of 
mass 56 is on a line twice the distance from the connector center of 
rotation 54 as is crankpin 52 and since the velocity of the center of 
connector rotation 54 in the direction of reciprocation is twice that of 
crankpin center 52 in the direction of reciprocation and since both have a 
velocity of zero in the direction perpendicular to the axis or 
reciprocation at midstroke, it follows that the velocity of the connector 
center of mass 56 is zero at midstroke. 
From FIG. 2, FIG. 6, FIG. 5, and FIG. 7, it can be seen that the combined 
energy of connector 14 and reciprocating member assembly 10 at the top of 
the stroke, the bottom of the stroke and both directions of reciprocation 
at midstroke respectively remains constant. This follows from the mass of 
connector 14 and the mass of reciprocating member assembly 10 being equal 
and from the velocities of the center of connector rotation 54 and the 
connector center of mass 56 being zero and twice the velocity of the 
crankpin center 52 respectively at the ends of the stroke and twice the 
velocity of crankpin center 52 and zero respectively at midstroke. 
The magnitude of the combined momentum of connector 14 and reciprocating 
member assembly 10 also remains unchanged from the top of the stroke, to 
midstroke, to the bottom of the stroke, to midstroke, and then back of the 
top of the stroke. The direction of the momentum at the ends of the stroke 
and midstroke is in the same direction of motion as is the crankpin center 
52 since the mass of connector 14 and mass reciprocating member assembly 
10 are equal and since at the ends of the stroke, the connector center of 
mass 56 has a velocity of twice that of crankpin center 52 while the 
reciprocating member assembly 10 has a zero velocity and at midstroke, the 
connector center of mass 56 has a zero velocity while the reciprocating 
member assembly 10 has,a velocity of twice that of the crankpin center 52. 
Thus, the magnitude of the combined momentum of connector 14 and 
reciprocating member assembly 10 remains unchanged with direction same as 
crankpin center 52. 
The resulting momentum in equation form is show in equation 1, where P is 
momentum M.sub.r is the mass of reciprocating member assembly 10, M.sub.c 
is the mass of connector 14, [V.sub.cp ] is the absolute velocity of the 
crankpin center 52, (2[V.sub.cp ])*(-sin Theta) is the velocity of 
reciprocation member assembly 10 which is the same as the connector center 
of rotation 54 and (2[V.sub.cp ])*cos Theta is the velocity of the 
connector center of mass 56. The equation can be reduced to the form shown 
in equation 2 or equation 3 in magnitude and of the same direction as 
crankpin center 52 Since M.sub.r =M.sub.c and since -sin theta and cos 
theta are 0 and 1, -1 and 0, 0 and -1, and 1 and 0 for 0 degrees, 90 
degrees, 180 degrees, and 270 degrees respectively where theta is 
referenced from the axis of reciprocation at the top of the stroke. Thus, 
P=M.sub.r *(2V.sub.cp) where P is the combined momentum of connector 14 
and reciprocating member assembly 10, where the mass of reciprocating 
member 10 is equal to the mass of connector 14, and where 2V.sub.cp is 
twice the directional velocity of crankpin center 52. Momentum is 
constant. 
FIGS. 3 and 4 illustrate mechanism 8 for clarity at positions other than 
the ends of the stroke and midstroke. In FIG. 3, mechanism 8 is at 30 
degrees from the top of the stroke. The crankpin center 52E has rotated 30 
degrees from the top of the stroke. The connector center of rotation 54E 
is on the axis of reciprocation at a distance of cos 30 degrees times 
twice the crankpin offset or 1.732 times the crankpin offset from drank 
center 50 and has a velocity along the axis of reciprocation of magnitude 
of sin 30 degrees times twice the velocity of crankpin center 52E or equal 
to 1.000 times the velocity of crankpin center 52E. The connector center 
of mass 56E is on a line through crank center 50 perpendicular to the axis 
of reciprocation at a distance of sin 30 degrees times twice the crankpin 
offset or 1.000 times the crankpin offset from crank center 50 and has a 
velocity along a line through crank center 50 perpendicular to the axis of 
reciprocation of magnitude of cos 30 degrees times twice the velocity of 
crankpin center 52E or of a magnitude equal to 1.732 times the velocity of 
crankpin center 52E. 
In FIG. 4, mechanism 8 is at 60 degrees from the top of the stroke. The 
crankpin center 52F has rotated 60 degrees from the top of the stroke. The 
connector center of rotation 54F is on the axis of reciprocation at a 
distance of cos 60 degrees times twice the crankpin offset or 1.000 times 
the crankpin offset from crank center 50 and has a velocity along the axis 
of reciprocation of magnitude of sin 60 degrees times twice the velocity 
of the crankpin center 52F or of a magnitude equal to 1.732 times the 
velocity of crankpin center 52F. The connector center of mass 56F is on a 
line through crank center 50 perpendicular to the axis of reciprocation at 
a distance of sin 60 degrees times twice the crankpin offset or 1.732 
times the crankpin offset from crank center 50 and has a velocity along a 
line through crank center 50 perpendicular of the axis of reciprocation of 
magnitude of cos 60 degrees times twice the velocity 
Equation 1 
EQU P=M.sub.r *(2[V.sub.cp ])*(-sin Theta)+M.sub.c *(2[V.sub.cp ])*cos Theta 
Equation 2 
EQU P=M.sub.r *(2[V.sub.cp ])*(-sin Theta+cos Theta) 
Equation 3 
EQU P=M.sub.r *(2[V.sub.cp ]) 
Equation 4 
EQU P=M.sub.r *(2[V.sub.cp ])*(-sin theta)+M.sub.c *(2[V.sub.cp ])*cos theta 
=M.sub.r *(2[V.sub.cp ])*(-sin theta+cos theta)=M.sub.r *(2V.sub.cp) 
of the crankpin center 52F or of a magnitude equal to 1.000 times the 
velocity of crankpin center 52F. 
The combined momentum of reciprocating member assembly 10 and connector 14 
of FIGS. 3 and 4 and for other angles other than at the end of the stroke 
and mid stroke is still the mass of reciprocating member assembly 10 times 
twice the velocity of crankpin center 52 or in the form of equation 4, 
where P is momentum, M.sub.r is the mass f reciprocating member assembly 
10, M.sub.c is the mass of connector 14 which is equal to M.sub.r, 
V.sub.cp and [V.sub.cp ] are the directional velocity and the absolute 
velocity respectively of the crankpin center 52, (2[V.sub.cp ]*(-sin 
theta) is the velocity of reciprocating member assembly 10 in the axis of 
reciprocation which is also the same as the connector center of rotation 
54, and (2[V.sub.cp ])*cos theta is the velocity of the connector center 
of mass 56 in the direction perpendicular to the axis of reciprocation. 
The quantity (-sin theta+cos theta) preserves the direction of velocity on 
a cartesian coordinate system where the top of the stroke is defined as 
the positive X axis and theta=0 degrees. The absolute value of (-sin 
theta+cos theta) is 1 as is demonstrated by the addition of velocities 
from FIG. 3 at 30 degrees from the top of the stroke for the center of 
connector rotation 54E and the connector center of mass 56E which are 
1.000 and 1.732 times the velocity of the crankpin center 52E 
respectively. Their vector summation is (1.sup.2 +1.732.sup.2).sup.0.5 =2 
or twice the magnitude of the velocity of crankpin center 52E. 
Use of the directional value of 2*(-sin theta+cos theta) yields directional 
values of -1.00 along the axis of reciprocation (X axis) and 1.732 along 
the line through crank center 50 perpendicular to the axis of 
reciprocation (Y axis) which is a vector of magnitude that is again twice 
that of the velocity of crankpin center 52E and in a direction the same as 
crankpin center 52E which is 30 degrees from the top of the stroke. The 
combined directional velocities as well as the combined absolute 
velocities of the center of connector rotation 54 and the connector center 
of mass 56 are twice that of the velocity of crankpin center 52 as 
demonstrated for FIG. 3. This can similarly be demonstrated for FIG, 4 
where the crankpin center 52F is 60 degrees from the top of the stroke and 
can similarly be demonstrated for any other crankpin angle. Since the 
masses of the reciprocating. member assembly 10 and the connector 14 are 
equal, their combined directional momentum is the mass of the 
reciprocating member assembly 10 times twice the directional velocity of 
crankpin center 52. 
The combined energy of reciprocating member assembly 10 and connector 14 
remains unchanged throughout the stroke unless there is a change in RPM 
due to an external force on crank assembly 12 or due to an external force 
on reciprocating member assembly 10 or due to frictional forces. This is 
best demonstrated by the combined energy of connector 14 and reciprocating 
member assembly 10 as shown at the top of the stroke in FIG. 2, at 
midstroke in FIG. 5, at the bottom of the stroke in FIG. 6, and at 
midstroke in the opposite direction in FIG. 7. 
The combined energy at the top of the stroke is half the mass of connector 
14 times the square of the velocity of the connector center of mass 56A 
where the velocity of the connector center of mass 56A is twice that of 
the velocity of crankpin center 52A. The energy of the reciprocating 
member assembly 10 is zero since its velocity is zero. Thus, the combined 
energy at the top of the stroke is twice the mass of connector 14 times 
the square of the velocity of crankpin 52A. The combined energy at the 
bottom of the stroke is the same. 
The combined energy at midstroke is half the mass of reciprocating 
mechanism 10 times the square of the velocity of the reciprocating 
mechanism 10 which is the same velocity as the center of connector 
rotation 54B where the velocity of the center of connector rotation 54B is 
twice that of the velocity of crankpin 52B. The energy of connector center 
mass 56B is zero since its velocity is zero. Thus, the combined energy at 
midstroke is twice the mass of reciprocating member assembly 10 times the 
square of the velocity for crankpin center 52B. The combined energy at 
midstroke in the opposite direction of reciprocation is also the same. 
Since the mass of connector 14 and the mass of reciprocating member 
assembly 10 are the same and since the velocity of crankpin center 52 
remains constant for positions 52A in FIG. 2, 52B in FIG. 5, 52C in FIG. 
6, and 52D in FIG. 7, the combined energy of connector 14 and 
reciprocating member assembly 10 remains constant, being equal to twice 
the mass of reciprocating member assembly 10 times the square of the 
velocity of crankpin center 52 for the top of the stroke, midstroke, the 
bottom of the stroke, and midstroke in the opposite direction. 
The combined energy of connector 14 and reciprocating member assembly 10 
remains constant throughout the entire stroke not just at the ends of the 
stroke and midstroke. This is best shown in equation 5, where E is energy 
M is mass, V is velocity, M.sub.r is the mass of reciprocating member 
assembly 10, V.sub.r is the velocity of reciprocating member assembly 10, 
M.sub.c is the mass of connector 14, V.sub.c is the velocity of connector 
center of mass 56, [V.sub.cp ] is the non directional magnitude of the 
velocity of crankpin center 52, (2[V.sub.cp ])*(-sin theta) is the 
velocity of reciprocating member assembly 10, and (2[V.sub.cp ]*cos theta 
is the velocity of the connector center of mass 56. 
Since (-sin theta).sup.2 +(cos theta).sup.2 =1 and since th mass of 
connector 14 (M.sub.c) is equal to the mass of reciprocating member 
assembly 10 (M.sub.r), equation 5 can be further simplified to equation 6. 
This can be further demonstrated in FIG. 3 where the magnitude of the 
velocity of the center of connector rotation 54E is twice that of the 
crankpin center 52E in the axis or reciprocation which is (-sin 
30.degree.)*2V.sub.cp =-V.sub.cp and the velocity of the connector center 
of mass 56E is twice the crankpin center 52E in the direction 
perpendicular to the axis of reciprocation which is (cos 
30.degree.)*2V.sub.cp =1.732 V.sub.cp. The combined energy of 
reciprocating member assembly 10 and connector 14 is as shown in equation 
7, where M.sub.c =M.sub.r. Similarly in FIG. 4, the magnitudes of the 
velocities of the center of connector rotation 54F and the connector 
center of mass 56F are (-sin 60.degree.)2*V.sub.cp =-1.732V.sub.cp and 
(cos 60.degree.)*2V.sub.cp -V.sub.cp respectively. The combined energy of 
reciprocating member assembly 10 and connector 14 is as shown in equation 
8, where M.sub.c =M.sub.r. 
Thus, unlike other rotary to reciprocating mechanisms, there is no constant 
transfer of kinetic energy back and forth throughout the stroke between 
the crank and the reciprocating member since the combined energy of 
connector 14 and the reciprocating member assembly 10 remains constant. 
The transfer of energy between crank assembly 12 and reciprocating member 
assembly 10 occurs only when there are external forces on crank assembly 
12, external forces on reciprocating member assembly 10 such as during 
compression and combustion and/or frictional forces. Since there is no 
transfer energy back and forth between crank assembly 12 and reciprocating 
member assembly 10 to accelerate and decelerate reciprocating member 
assembly 10, the forces encountered by the secondary intersurface are 
independent of the RPM of mechanism 8. 
As described, the reciprocating member including the connecting link and 
the reciprocating portion of the mechanism whether a pump, a compressor, 
an engine, or some other reciprocating member have zero velocity, zero 
momentum, and zero energy at the bottom of the stroke and at the top of 
the stroke. Also, the connector has zero translational velocity, zero 
translational momentum, and zero translational energy at midstroke in both 
directions of reciprocation. The connector's rotational velocity, 
momentum, and energy remains constant unless external forces change the 
RPM. As a result, there is no transfer of energy between the crank, and 
the reciprocating member from one end of the stroke to the other end of 
the stroke unless the combined kinetic energy of the crank, connector, and 
the reciprocating member is affected by an external force. 
Equation 5 
EQU E=1/2MV.sup.2 =1/2M.sub.r V.sub.r 2+1/2M.sub.c V.sub.c 2=1/2M.sub.r 
*[(2[V.sub.cp ])*(-sin theta)].sup.2 +1/2M.sub.c *[(2[V.sub.cp ])*cos 
theta].sup.2 
Equation 6 
EQU E=1/2M.sub.r *(2[V.sub.cp ]).sup.2 *[(-sin theta).sup.2 +(cos theta).sup.2 
[=2M.sub.r *V.sub.cp.sup.2 *(1)=2M.sub.r *V.sub.cp.sup.2. 
Equation 7 
EQU E=1/2M.sub.r *(-V.sub.cp).sup.2 +1/2M.sub.c *(1.732V.sub.cp).sup.2 
=2M.sub.r *V.sub.cp.sup.2 
Equation 8 
EQU E=1/2M.sub.r *(-1.732V.sub.cp).sup.2 +1/2M.sub.c *(V.sub.cp).sup.2 2M.sub.r 
*V.sub.cp.sup.2 
In terms of energy, the reciprocating member assembly 10 has maximum 
velocity and energy at midstroke and zero energy at the top and the bottom 
of its stroke where its velocity is zero as it switches directions. 
Without novel connector counterweights 42A and 42B and during no load 
conditions from external forces, reciprocating member assembly 10 receives 
kinetic energy from crank assembly 12 from the top of the stroke to 
midstroke and from the bottom of the stroke to midstroke and returns the 
kinetic energy to the crank assembly from midstroke to the top of the 
stroke and from midstroke to the bottom of the stroke. 
Although the primary interface transfers the energy at the top and the 
bottom of the stroke, the secondary interface encounters the forces 
necessary to transfer the energy through midstroke. Energy transferred 
back and forth from crank assembly 12 to reciprocating member assembly 10 
will decrease as the mass of the connector counterweights 42A and 42B 
increase on the side opposite hole 46 than is connector cylindrical 
portion 40. The energy transfer between crank assembly 12 and 
reciprocating member assembly 10 will approach zero as the mass and 
location of connector counterweights 42A and 42B is such that the mass of 
connector 14 approaches the mass of reciprocating member assembly 10 and 
the connector center of mass 56 approaches a distance equal and opposite 
from the hole 46 receiving crankpin 34 as is the center of connector 
rotation 54 of cylindrical portion 40 of connector 14. 
The use of connector counterweights 42A and 42B as further described in 
FIGS. 11a-11d and FIGS. 12a-12d is inclusive of the specific subset 
described in FIGS. 1-7 and corresponding ones of FIGS. 8a-8f. In FIGS. 
11a-11d, and FIGS. 12a-12d connector counterweights 42A and 42B are of 
mass and location such that the resulting mass of connector 14 is 
substantially equal to the mass of reciprocating member 10 times the 
distance of the center of connector rotation 54 to the center of hole 46 
divided by distance of the connector center of mass 56 to the center of 
hole 46 where hole 46 which receives crankpin 34 is located on a line 
connecting the center of connector rotation 54 and the connector center of 
mass 56. Thus the product of the mass of connector 14 times the distance 
from its center of mass 56 to crankpin center 52 is substantially equal to 
the product of the mass of reciprocating member 10 times the distance of 
the center of connector rotation 54 to crankpin center 52 where the center 
of connector rotation 54 and the connector center of mass 56 are in 
opposite directions from crankpin center 52. 
The proper addition of counterweights 42A and 42B allows the secondary 
interface to be sized to handle loads encountered by reciprocating portion 
24 in doing work or by work done on it regardless of RPMs and the 
resulting inertia forces. This decreases the necessary size of secondary 
interfaces for higher speed applications for both types of secondary 
interfaces, those between the connector and the housing and those between 
the crank and the rod assembly. A secondary interface may be nominal or 
not even be necessary for those applications where there is a load only on 
the ends of the stroke with none a midstroke. 
The crank assembly 12 in FIG. 1 includes flywheel 64 and crank 
counterweights 62A and 62B. The flywheel 64 is not required to supply 
energy to accelerate and decelerate the reciprocating member 10 since the 
novel connector design incorporating connector counterweights 42A and 42B 
does this. However, the flywheel 64 should be sized to reduce fluctuations 
in crank velocity due to work done by or on reciprocating portion 24 of 
reciprocating member 10. 
The crank counterweights 62A and 62B are sized to oppose the translational 
inertia forces of reciprocating member 10 in the axis of reciprocation and 
the translational inertia forces of connector 14 in the axis perpendicular 
to the axis of reciprocation. The crank counterweights 62A and 62B can 
cancel out the combined translational inertia forces of reciprocating 
member 10 and novel connector 14 as described since these forces are equal 
but 90 degrees out of phase. 
FIGS. 8a-8f shows crank center 50, crankpin center 52, the center of 
connector rotation 54, and the connector center of mass 56 for 0 degrees, 
30 degrees, 60 degrees, 90 degrees, 180 degrees and 270 degrees. From 
FIGS. 8a-8f, it can be understood that crankpin center 52A-F is central to 
the connector center of mass 56A-F and the center of connector rotation 
54A-F which are respectively the center of mass of connector 14 and the 
central location that the mass of reciprocating member 10 acts upon. 
Mechanism 8 can be fully balanced by the addition of crank counterweights 
62A and 62B that are opposite crankpin center 52 on a line through 
crankpin center 52 and crank center 50 and that are sized to oppose the 
momentums of reciprocating member 10 and connector 14 whose momentums are 
perpendicular and 90 degrees out of phase with each other and when 
combined act centrally on crankpin center 52 with constant momentum that 
is twice the mass of the reciprocating member 10 times the directional 
velocity of crankpin center 52. 
As described earlier, the combined momentum of reciprocating member 10 and 
connector 14 through the entire stroke is the mass of reciprocating member 
10 times twice the velocity of crankpin center 52 or in the form of 
equation 9 where P is momentum, M.sub.r is the mass of reciprocating 
member 10, M.sub.c is the mass of connector 14 which is equal to M.sub.r, 
V.sub.cp and [V.sub.cp ] are the directional velocity and the absolute 
velocity respectively of the crankpin center 52, (2[V.sub.cp ])*(-sin 
theta) is the velocity of reciprocating member 10 which is the same as the 
center of connector rotation 54, and (2[V.sub.cp ])*cos theta is the 
velocity of the connector center of mass 56. 
Mechanism 8 can be fully balanced by the addition of crank counterweights 
62A and 62B to 
Equation 9 
EQU P=M.sub.r *(2[V.sub.cp ])*(-sin theta)+M.sub.c *(2[V.sub.cp ])*cos 
theta=M.sub.r *(2[Vcp]) *(-sin theta+cos theta)=M.sub.r *(2V.sub.cp) 
Equation 10 
EQU P.sub.cc =M.sub.cc *V.sub.cc =-M.sub.r *(2V.sub.cp)=-P 
crank assembly 12 that have the same absolute momentum as the combined 
translational momentum of reciprocating member 10 and connector 14 and 
that have an orientation opposite the crank center 50 as is the crankpin 
center 52. The crank counterweights 62A and 62B have momentums shown in 
equation 10 where P.sub.cc is the momentum, M.sub.cc is the mass, and 
V.sub.cc is the velocity of the crank counterweights 62A and 62B. 
The inertia forces of crank counterweights 62A and 62B are thus outward 
from crank center 50 in a direction opposite crankpin center 52 and are of 
equal magnitude of the combined translational inertia forces of 
reciprocating member 10 and connector 14. The outward (centrifugal) 
inertia forces of crank counterweights 62A and 62B thus oppose the 
translational inertia forces of reciprocating member 10 at the top a and 
the bottom of the stroke, the translational inertia forces of connector 14 
at midstroke in both directions, and the combined translational inertia 
forces of reciprocating member 10 and connector 14 between midstroke and 
the end of the strokes. Crank counterweights 62A and 62B are sized to also 
balance the outward (centrifugal) inertia force of crankpin 34. 
FIG. 9 is a longitudinally-sectioned, elevational view of an engine 8A and 
FIG. 10 is a simplified plan view, in section of engine 8A with 
reciprocating member 10A that includes rod assembly 20A, a double-acting 
piston 24A, and a rod connecting link 22A between the two. The rod 
assembly 20A is confined to reciprocation by rod constraining surfaces 17A 
and 18A in housing 16A. Crankpin 34A is rotating counterclockwise through 
midstroke while connector 14A is rotating clockwise around crankpin 34A. 
Cylindrical portion 40A of connector 14A is confined to reciprocation by 
rod assembly 20A which in turn is confined to reciprocation by surfaces 
17A and 18A. Rod assembly 20A includes rod assembly portions 21C and 21D 
which house cylindrical portion 40A of connector 14A and are assembled 
together with bolts 26C and 26D. The connector 14A includes connector side 
secondary interfaces 44C and 44D, which engage housing side secondary 
interfaces 72A and 72B in one direction through midstroke and 72C and 72D 
in the opposite direction through midstroke. The connector 14A also 
includes connector counterweights 42C and 42D. 
The crank assembly 12A includes crankpin 34A and crank portions 32C and 32D 
where crankpin 34A is solid to crank portion 32C and crank portion 32D is 
assembled to crankpin 34A after connector 14A is slid into position. 
Various other methods of construction are possible such as assembling 
connector 14A onto crankpin 34A of a unit construction crank 12A rather 
than sliding connector 14A onto crank pin 34A. 
The crank assembly 12A which is rotating counterclockwise also includes 
flywheel 64A and crank counterweights 62C and 62D. The crankpin 34A 
receives oil from the main bearings as is typical of most engines. An oil 
line 101 or multiple oil lines 101 provide(s) oil to the surfaces of 
crankpin 34A for lubrication between bearing surfaces of crankpin 34A and 
connector 14A and provides oil to oil lines 100 in cylindrical portion 40A 
of connector 14A. 
The connector 14A is assembled onto crankpin 34A and cylindrical portion 
40A is housed in the rod assembly 20A. The connector 14A is shown at 
midstroke with connector side secondary interfaces 44c and 44D engaging 
housing side secondary interfaces 72A and 72B in one direction of 
midstroke. The connector 14A is rotating clockwise at an equal and 
opposite angular velocity as is crank assembly 12A. The connector 
counterweights 42C and 42D are shown at one end of their movement which 
occurs at midstroke with their inertia forces equal and opposite those of 
crank counterweights 62C and 62D. In the opposite direction of midstroke, 
180 degrees later, the connector counterweights 42C and 42D Will be at the 
other end of their movement with their inertia forces again equal and 
opposite those of crank counterweights 62C and 62D. 
At the end of the strokes, the crank counterweights 62C and 62D will oppose 
the inertia forces of the reciprocating member 10A. Oil lines 100 in 
cylindrical portion 40A provide oil to lubricate the bearing surfaces 
between cylindrical portion 40A and rod assembly 20A and also channels oil 
to oil line 102 in reciprocating member 10A. This oil can also be 
channeled to provide lubrication to the secondary interface. 
The reciprocating member 10A is shown with piston 24A, rod connecting link 
22A, and rod assembly portion 21C as a unit construction with bolts 26C 
and 26D fastening rod assembly portion 21D to portion 21C to house 
cylindrical portion 40A of connector 14A. The reciprocating member 10A may 
be constructed in various manners such as piston 24A being assembled to 
rod connecting link 22A which is assembled to or solid to rod assembly 
portion 21C. The piston 24A is shown as a double acting piston with 
piston/oil rings 90 on both ends of piston 24A. The oil line 102 provides 
cooling to rod connecting link 22A and piston 24A. One passage in oil line 
102 would provide oil to piston 24A and the other passage would return oil 
to rod assembly portion 21C. Oil line 102 receives oil from oil lines 100 
in cylindrical portion 40A of connector 14A which receives oil from oil 
lines 101 in crankpin 34A. The piston 24A may also be constructed from 
ceramic materials and may require minimal or no cooling. 
The upper portion of engine 8A includes upper head 94A, cylinder block 94B, 
and lower head 94C which include water lines 80 for cooling diesel fuel 
injectors 86, exhaust ports 84 and intake ports 82A and 82B. Bolts 92 pass 
through upper head 94A, cylinder block 94B, and lower head 94C and are 
threaded into housing 16A and 16B. Various other methods of construction 
may be practiced including combining block 94B with either head 94A or 
94C. Water lines 80 are conventional. Cooling fins could also be used. 
Fuel injectors 86 are conventional, however they could also be designed so 
their timing could easily be advanced especially for two cycle diesel 
engines where fuel burn time and scavenging are negatively affected by 
increased RPM. One such method would be solenoid activated injectors that 
are microprocessor controlled. Lower block 94C includes piston rings 88 to 
isolate combustion chamber 108 from the crank connector and rod assembly. 
Vent 89 between the rings helps minimize combustion particles entering the 
housing. 
Intake ports 82A and 82B supply air to both combustion chambers 106 and 
108. Not shown is a blower or supercharger that could be any conventional 
blower or compressor inclusive of roots blowers and screw, gear, and vane 
compressors that provides positive air pressure to intake ports 82A and 
82B. Exhaust ports 84 exhausts gases from combustion chambers 106 and 108. 
The piston 24A uncovers exhaust ports 84 and intake ports 82A and 82B to 
combustion chamber 108 at the top of the stroke as combustion chamber 106 
completes compression and commences ignition and uncovers combustion 
chamber 106 at the bottom of the stroke as combustion chamber 108 
completes compression and commences ignition. 
The length of piston 24A is of a length substantially that of the length of 
the stroke less the length of the exhaust ports. The flow of gases out of 
exhaust ports 84 and the flow of air in through ports 82A and 82B is 
similar to conventional two cycle engines except exhaust ports 84 and 
intake ports 82A and 82B serve to remove gases and supply air to two 
combustion chambers instead of one. However, piston 24A could be built 
sufficiently longer than the stroke so that separate intake ports and 
separate exhaust ports would communicate with combustion chambers 106 and 
108. The centers of intake ports 82A and 82B are located between 90 
degrees and 120 degrees from the center of exhaust ports 8 and are angled 
to supply air in a direction toward the tops of the combustion chambers 
and to the side opposite exhaust ports 84. The air from intake ports 82A 
and 82B moves towards the top of the chamber, over, and back toward 
exhaust ports 84 as gases continue to escape through exhaust ports. 84. 
The intake port 82A favors flow into combustion chamber 106 while intake 
port 82B favors flow into combustion chamber 108. Both intake ports supply 
air to each combustion chamber, however, intake ports 82A and 82B supply 
different amounts of air to different parts of the combustion chamber 
since their upward angles are different. This also encourages swirl 
resulting in better mixing of fuel during injection. 
Although one specific method of port construction was described, other more 
conventional methods of port construction or valves may be used. Intake 
ports and exhaust ports could be 180 degrees apart. Intake ports and 
exhaust valves or vice versa may also be incorporated The construction 
could also be changed to a four cycle design using only valves. However 
this would reduce the number of power strokes to one per revolution unless 
a second piston is added. A second double acting piston could be added to 
the same rod connecting link or a second rod connecting link could be 
attached of the rod assembly opposite the first with a second double 
acting piston to achieve two strokes per revolution for a four cycle 
engine. Two strokes per revolution could also be achieved with a two cycle 
engine with two single acting pistons that are either located on one rod 
connecting link or on opposed rod connecting links. 
Engine 8A in FIGS. 9 and 10 is shown as a two cycle diesel with one double 
acting piston 24A resulting in two power strokes per revolution. In the 
preferred embodiment, it is desirable for piston 24A and cylinder walls 
9A-C to be made from materials such as ceramics to allow the engine to 
operate at higher temperatures. Thick thermal barrier coats on metal may 
also be used to achieve higher engine temperatures. These materials are 
fundamental to the development of higher efficiency low heat rejection 
diesel engines. Higher cylinder temperatures are also desirable to 
decrease fuel burn time and thus improve the efficiency of the diesel 
cycle at higher RPMs and/or to increase the engine horsepower to weight 
ratio. Higher temperature materials are desirable to better utilize the 
novel connector counterweights 42C and 42D which eliminate the effect of 
inertia forces on the secondary interface and permit higher possible 
engine RPMs. 
Advanced materials involving cutting edge technologies can be more easily 
incorporated into the design of engine 8A and utilized than conventional 
engines for several reasons. First, there are no side thrust forces from 
piston 24A on cylinder walls 94B. Second, the combustion portion of the 
engine is removed significantly from the rotary to reciprocating mechanism 
portion as compared to those engines utilizing connecting rods. Third, the 
application of higher temperature materials can be more economically 
incorporated since only one piston and one cylinder are required for 
engine 8A which produces two power strokes per revolution, which is 
equivalent to a four cylinder, four cycle engine with single acting 
pistons. Fourth, the benefits of higher temperature and low thermal 
conductive materials are greater for double acting pistons than single 
acting pistons since double acting pistons cannot remove heat build up as 
easily. 
FIGS. 9 and 10 described one specific method of engine construction using a 
connector resulting in a stroke that is four times the crankpin offset 
where the connector has novel connector counterweights that eliminate the 
transfer of energy back and forth from the crank to the reciprocating 
member and allows engine 8A to achieve high RPMs without increasing the 
size of the secondary interface. However, the construction an be varied 
from construction of components to methods of assembly. The construction 
may be varied to be inclusive of a secondary interface between the housing 
and the connector, or a secondary interface between the crank and the rod 
assembly, or no secondary interface. Also, the specific application 
described is not limited 60 diesel engines. The use of connector 
counterweights is very applicable to gasoline engines since even though 
the weight for comparative reciprocating parts are usually less, they 
generally turn higher RPMs. The use of connector counterweights is also 
very applicable to external combustion engines, pumps, and compressors 
especially at higher RPMs. 
The application of a connector resulting in a stroke four times the 
crankpin offset and with connector counterweights to eliminate that 
transfer of energy back and forth between the crank and the reciprocating 
member is also very applicable to any rotary to reciprocating mechanism 
especially those that operate at high RPM and with large inertia forces. 
The use of connector counterweights is similarly effective for 
applications using a secondary interface between the crank and the rod 
assembly and not limited to just those applications with the secondary 
interface between the connector and the housing. Also, the use of 
connector counterweights can reduce the necessary size, and in some cases 
eliminate the need of a secondary interface for those applications where 
there are loads only at the ends of the strokes. This would not be 
possible for high RPM applications without connector counterweights due to 
the magnitude of the inertia forces through midstroke. In these cases, the 
reciprocating mechanism would fall behind the crankpin as it passed 
through midstroke resulting in excessive forces and friction as it caught 
back up after midstroke or it may even jam. 
Mechanism 8A is equally applicable to gasoline engines as well as diesels 
even though FIGS. 9 and 10 primarily described a diesel engine 
application. This reflects the desire to move the consumer toward the more 
energy efficient engine cycle especially since this design provides a 
number of features that would make a diesel engine more attractive to a 
broader base of consumers. 
Some advantages are: (1) the cost savings and simplicity of a one cylinder 
diesel engine with as many power strokes per revolution as a four cylinder 
four cycle diesel is attractive; (2) the inertia forces can be totally 
balanced with but three moving assemblies: the crank assembly, the novel 
connector, and the reciprocating member; (3) a single cylinder engine has 
lower heat losses than a four cylinder engine; (4) a single cylinder 
diesel engine is easier to preheat for cold weather starts; (5) since only 
one piston is required and since that piston does not experience side 
thrust forces, more sophisticated piston designs in exotic materials are 
cost effective, piston weight can be reduced and diesel engine RPM can be 
increased and engine size decreased by increasing piston/cylinder 
temperatures through the use of higher temperature materials; (6) a single 
cylinder engine with only one piston encounters lower frictional forces 
than four cylinder engine; and (7) the smaller size and the lower center 
of mass makes the engine design attractive in the transportation industry. 
One specific subset of connector counterweights, for convenience and ease 
of illustration, has been described for a mechanism with a stroke that is 
four times the crankpin offset that can be fully balanced with just one 
crank, one reciprocating mechanism, and one connector where kinetic energy 
is transferred back and forth between the connector and the reciprocating 
mechanism instead of the crank and the reciprocating member thus 
eliminating excessive forces on the secondary interface due to inertia 
forces and eliminating fluctuations in crank velocity under no load 
conditions. As described in connection with FIGS. 1-7 and 8a-8f, this can 
be accomplished by the addition of connector counterweights so that the 
magnitude of the connector translational momentum in the direction 
perpendicular to the axis of reciprocation is equal to but 90 degrees out 
of phase with the translational momentum of the reciprocating member in 
the axis of reciprocation and where the magnitude of the translational 
momentum of the connector in the direction of reciprocation is zero. This 
can also be accomplished by the addition of connector counterweights so 
that the magnitude of the connector translational momentum in the 
direction perpendicular to the axis of reciprocation is equal to but 90 
degrees of phase with the combined translational momentum of the 
reciprocating member and the connector in the direction of the axis of 
reciprocation and where FIGS. 1-7 and 8a-8f show a specific subset of this 
motion where the magnitude of the translational momentum of the connector 
in the direction of reciprocation was zero. 
Without the novel use of connector counterweights, the motion of the 
connector center of mass is substantially an ellipse with the major axis 
on the axis of reciprocation. The ellipse defining the motion of the 
connector center of mass approaches or becomes a straight line falling on 
the axis of reciprocation for the most basic connector. The crank not only 
accelerates and decelerates the reciprocating member in the axis of 
reciprocation but also the connector. 
However, the addition of connector counterweights can be used to change the 
location of the connector center of mass and its resulting motion in 
unique ways unlike the effect of adding crank counterweights. The addition 
of connector counterweights changes the shape and size of the elliptical 
motion of the connector center of mass and advantageously capitalizes on 
the unique motion of the connector which is again is defined by combined 
motion of the primary mechanism plus the secondary interface through 
midstroke. 
The minor axis of the ellipse defining the motion of the connector center 
of mass increases with the addition of connector counterweights on the 
side of the connector opposite the hole receiving the crankpin as is the 
connector center of rotation. Counterweights can continue to be added to 
the side opposite the center of connector rotation until the center of the 
hole receiving the crankpin will become the center of mass for the 
connector. This geometry results in a motion for the connector center of 
mass that coincides with the motion of the center of the crankpin. The 
minor axis of the elliptical motion of the connector in a direction 
perpendicular to the axis of reciprocation is now equal to the major axis 
in the direction of reciprocation resulting in a circle with a diameter 
that is twice the crankpin offset. The combined motion of the connector 
and the reciprocating member is now such that the crank accelerates and 
decelerates only the reciprocating member since the magnitude of the 
momentum of the connector remains constant. The energy of the connector 
also remains constant. 
The further addition of connector counterweights can be used to extend the 
connector center of mass away from the hole receiving the crankpin in the 
direction opposite the center of connector rotation. This, in effect, 
increases the velocity and the resulting energy of the connector in the 
direction perpendicular to the axis of reciprocation as compared to its 
velocity and resulting energy in the direction of reciprocation. 
The energy of the connector is thus greater at the top of the stroke When 
the reciprocating member has zero energy than the energy of the connector 
at midstroke when the reciprocating member is at its maximum energy. This 
reduce the transfer of energy back and forth between the crank and the 
reciprocating member. The motion of the connector center of mass, again, 
becomes an ellipse, this time with the major axis perpendicular to the 
axis of reciprocation. Once again the crank must accelerates and 
decelerates the connector but primarily in the axis perpendicular to the 
axis of reciprocation and 90 degrees out of phase with acceleration and 
deceleration of the reciprocating member. 
To summarize, the motion of the connector center of mass is defined as an 
ellipse with the magnitude of the connector's momentum and the resulting 
transfer of energy between the crank and the connector/reciprocating 
mechanism being dependent on the direction of the major axis of the 
ellipse. Three conditions exist, which are: (1) when the major axis of the 
ellipse defining the motion of the connector's center of mass is on the 
axis of reciprocation, then the motion of the connector is in phase with 
the reciprocating member thus increasing the transfer of energy back and 
forth from the crank; (2) when the major axis of the ellipse defining the 
motion of the connector's center of mass is on neither axis in the case of 
a circle, then the motion of the connector is a circle having no affect on 
the transfer of energy back and forth from the crank; and (3) when the 
major axis of the ellipse defining the motion of the connector's center of 
mass is on the axis perpendicular to the axis reciprocation, then the 
motion of the connector is out of phase with the reciprocating member thus 
reducing the transfer of energy back and forth from the crank. 
The use of connector counterweights addresses condition 3 to minimize the 
transfer of energy back and forth from the crank to reduce loads on the 
secondary interface through midstroke. The amount of energy transferred 
back and forth from the crank as described in condition 3 is further 
dependent on the shape of the ellipse and the mass of the connector 
relative to the mass of the reciprocating member. 
Condition 3, in which the motion of the connector center of mass is an 
ellipse with the major axis perpendicular to the axis of reciprocation, 
cam be further broken down into three subsets of motion all of which can 
reduce/eliminate the transfer of energy back and forth between the crank 
and the reciprocating member. 
One of the three conditions is the subset of motion as shown FIGS. 1-7 and 
8a-8f where the mass of connector 14 is equal to the mass of reciprocating 
member 10 and where the distance from the center of crankpin 52 to the 
connector center of mass 56 is equal and opposite the distance from the 
center of crankpin 52 to the center of connector rotation 54. The ellipse 
for this motion becomes a straight line as the minor axis of the ellipse 
goes to zero. The magnitude of the translational momentum of connector 14 
in the direction perpendicular to axis of reciprocation 53 is equal to but 
90 degrees out of the phase with the combined translational momentum of 
reciprocating member 10 and connector 14 in the direction of the axis of 
reciprocation 53. 
In the specific case shown in FIGS. 1-7 and 8a-8f the magnitude of the 
translational momentum of connector 14 in the direction of the axis of 
reciprocation 53 is zero thus the magnitude of the translational momentum 
of connector 14 in the direction perpendicular to the axis of 
reciprocation 53 is equal to but 90 degrees out of phase with the 
translational momentum of reciprocating member 10 in the direction of the 
axis of reciprocation 53. 
In the two other cases, the magnitude of the translational momentum of the 
connector in the direction perpendicular to the axis of reciprocation is 
equal to but 90 degrees out of phase with the combined translational 
momentum of the reciprocating member and the connector in the direction of 
reciprocation. In one case the mass of the connector is greater than the 
mass of the reciprocating member and the direction of rotation of the 
elliptical motion of the connector's center of mass is in the same 
direction of rotation as the crankpin while in the other case the mass of 
the connector is less than the mass of reciprocating member and the 
direction of rotation of the connector's center of mass is in the opposite 
direction. In both cases the distance from the crankpin center to the 
connector center of mass is equal to the crankpin offset (distance from 
the crankpin center to the center of connector rotation) times the mass of 
the reciprocating member divided the mass of the connector. 
FIGS. 11a-11d are four successive stages in a developed view illustrating 
the use of connector 14 whose mass is twice that of reciprocating member 
10 while FIGS. 12a-12d are four successive stages in a developed view 
illustrating the use of connector 14 whose mass is one half that of 
reciprocating member 10. This distance from crankpin center 52 to 
connector center of mass 56 is one half the crankpin offset and twice the 
crankpin offset respectfully. 
In FIGS. 11a-11d the center of crank rotation is 50A, the crankpin center 
is 52G, 52H, 52I, and 52J for 0, 30, 60 and 90 degrees respectively, the 
center of connector rotation is 54G, 54H, 54I and 54J for 0, 30, 60, and 
90 degrees respectively, and the connector center of mass is 56G, 56H, 
56I, and 56J for 0, 30, 60, and 90 degrees respectively. The crankpin 
center, the center of connector rotation, and the connector center of mass 
will still be referred to as 52, 54, and 56 respectfully unless a specific 
angle is referenced. The distance from crankpin center 52 to the center of 
connector rotation 54 is one crankpin offset as defined earlier for 
mechanisms with a stroke four times the crankpin offset. The distance from 
crankpin center 52 to the connector center of mass 56 is one half the 
crankpin offset since the mass of the connector 14 is twice that of the 
reciprocating member 10. 
The velocity of the connector center of mass 56 in the direction 
perpendicular to the axis of reciprocation is 1.5 times crankpin center 52 
in the same direction. This can be best shown in FIG. 11a at 0 degrees 
where the center of connector rotation 54G has zero velocity at the top of 
the stroke and the distance from the center of connector rotation 54G to 
the connector center of mass 56G is 1.5 times the crankpin offset. The 
velocity of the connector center of mass 56 in the direction of 
reciprocation is 0.5 times crankpin center 52 in the same direction. This 
is shown in FIG. 11d at 90 degrees where at midstroke the center of 
connector rotation 54J has a velocity that is twice that of crankpin 
center 52J in the direction of reciprocation, and the velocity of 
connector center of rotation 54J and crankpin center 52J have zero 
velocities in the direction perpendicular to the axis of reciprocation, 
and where the distance from the center of connector rotation 54J to the 
connector center of mass 56J is again 1.5 times the crankpin offset. 
The magnitude of the combined momentums for FIG. 11a is shown in equations 
11-13 where P is momentum, Mr is the mass of reciprocating member 10, Mc 
is the mass of connector 14, [Vcp] is the absolute velocity of the 
crankpin center 52, 2[Vcp]*(-sin theta) is velocity of the reciprocating 
member 10 in the direction of reciprocation, (0.5[Vcp])*(-sin theta) is 
the velocity of the connector in the direction of reciprocation, and 
(1.5[Vcp])*(cos theta) is the velocity of connector center of mass 56 in 
the direction perpendicular of the axis of reciprocation. Since Mc=twice 
Mr, equation 11 can be combined into equation 12. Equation 12 can reduced 
to equation 13. Thus P=Mr*(3Vcp) where P is the combined momentum of 
reciprocating member 10 and the connector 14 which has mass that is twice 
and the mass of the reciprocating member 10. The combined momentum is 
equal to 3 times the mass of the reciprocation member 10 times the 
directional velocity of the crankpin center 52. 
The terms combine in equation 12 from equation 11 such that the momentum of 
connector 14 in the direction perpendicular to the axis of reciprocation 
is equal to and 90 degrees out of phase with the combined momentum of 
reciprocating member 10 and 
Equation 11 
EQU P=Mr*(2[Vcp])*(-sin theta)+Mc*(0.5[Vcp)*(-sin theta)+Mc*(1.5[Vcp])*(cos 
theta) 
Equation 12 
EQU P=Mr*(3[Vcp])*(-sin theta)+Mr*(cos theta) =Mr*(3[Vcp])*(-sin theta+cos 
theta) 
Equation 13 
EQU P=Mr*(3[Vcp]) 
connector 14 in the direction of reciprocation. Also the terms combine in 
equation 13 such that the magnitude of the combined momentum remains 
constant. 
FIGS. 12a-12d illustrates the use of a connector 14 whose mass is one half 
that of the reciprocating member 10. The distance from crankpin center 52 
to the connector center of mass 56 is twice the crankpin offset. In FIG. 
12 the center of crank rotation is 50B, the crankpin center is 52K, 52L, 
52M, and 52N for 0, 30, 60, and 90 degrees respectively, the center of 
connector rotation is 54K, 54L, 54M and 54N for 0, 30, 60, and 90 degrees 
respectively, and the connector center of mass is 56K, 56L, 56M, and 56N 
for 0, 30, 60, and 90 degrees respectively. The crankpin center, the 
center of connector rotation, and the connector center of mass will again 
be referred to as 52, 54, and 56 respectfully unless a specific angle is 
referenced. The distance from crankpin center 52 to the center of 
connector rotation 54 is again one crankpin offset. The distance from 
crankpin center 52 to connector center of mass 56 is twice the crankpin 
offset since the mass of connector 14 is one half the mass of 
reciprocating member 10. 
The velocity of the connector center of mass 56 in the direction 
perpendicular to the axis of reciprocation is 3.0 times crankpin center 52 
in the same direction. This can be best shown in FIGS. 12a-12d at 0 
degrees where the center of connector rotation 54K has zero velocity at 
the top of the stroke and the distance from the center of connector 
rotation 54K to the connector center of mass 56K is 3 times the crankpin 
offset. The velocity of the connector center of mass 56 in the direction 
of reciprocation is the same as the velocity of the crankpin center 52 but 
in the opposite direction. This can be best shown in FIG. 12d at 90 
degrees where at midstroke the center of connector rotation 54N has a 
velocity that is twice that of crankpin center 52N in the direction of 
reciprocation, and the velocity of connector center of rotation 54N and 
crankpin center 52N have zero velocities in the direction perpendicular to 
the axis of reciprocation, and where the distance from the center of 
connector rotation 54N of the connector center of mass 56N is again 3 
times the crankpin offset. 
The magnitude of the combined momentums for FIG. 12a is shown in equations 
14-16, where P is momentum, Mr is the mass of reciprocating member 10, Mc 
is the mass of connector 14, [Vcp]is the absolute velocity of crankpin 
center 52, 2[Vcp]*(-sin theta) is the velocity of reciprocating member 10 
in the direction of reciprocation, (-[Vcp])*(-sin theta) is the velocity 
of the connector center of mass 56 in the direction of reciprocation, and 
(3[Vcp])*(cos theta) is the velocity of the connector center of mass 56 in 
the direction perpendicular to the axis of reciprocating. 
Since Mc=0.5 *Mr, equation 14 can be combined into equation 15. Equation 15 
can be reduced to equation 16. Thus P=Mr*(1.5Vcp) where P is the combined 
momentum of reciprocating member 10 and connector 14 whose mass is half 
the mass of the reciprocating member 10. The combined momentum equal to 
1.5 times the mass of reciprocation member 10 times the directional 
velocity of the crankpin center 52. 
The terms combine in equation 15 from equation 14 such that the momentum of 
connector 14 in the direction perpendicular to the axis of reciprocation 
is equal to and 90 degrees of phase with the combined momentum of 
reciprocating member 10 and connector 14 in the direction of 
reciprocation. Also note that the terms combine in equation 16 such 
Equation 14 
EQU P=Mr*(2[Vcp])*(-sin theta )+Mc*(-[Vcp])*(-sin theta)+Mc*(3[Vcp])*(cos theta 
) 
Equation 15 
EQU P=Mr*(1.5[Vcp])*(-sin theta)+Mr*(1.5{Vcp])*(cos theta)=Mr*(1.5[Vcp])*(-sin 
theta+cos theta) 
Equation 16 
EQU P=Mr*(1.5[Vcp]) 
that the magnitude the combined momentum remains constant. 
Crank counterweights 62A and 62B as described in FIG. 1 can once again be 
used to fully balance the mechanism since the combined magnitude of the 
momentums of connector 14 and reciprocating member 10 remain constant with 
a direction the same as crankpin center 52. 
The combined energy of connector 14 and reciprocating member 10 in FIGS. 
11a-11d remains constant throughout the entire stroke. This is best seen 
in equation 17, where E is energy, M is mass, V is velocity, Mr is the 
mass of reciprocating member 10, Vr is the velocity of reciprocating 
member 10, Mc is the mass of connector 14, Vc is the velocity of the 
connector center of mass 56, [Vcp] is the nondirectional magnitude of the 
velocity of crankpin center 52, (2[Vcp]*(-sin theta) is the velocity of 
the reciprocating member 10 in the direction of reciprocation, 
(0.5[Vcp])*(-sin theta) is the velocity of the connector center of mass 56 
in the direction of reciprocation and (1.5[Vcp])*(cos theta) is the 
velocity of the connector center of mass 56 in the direction perpendicular 
to the axis of reciprocation. 
The resulting energy of reciprocating member 10 and connector 14, for FIG. 
11 where the mass of connector 14 is twice that of the reciprocating 
member 10 and where the distance from crankpin center 52 to the connector 
center of mass 56 is one half the distance from the crankpin center 52 to 
the center of connector rotation 54 (crankpin offset), is 2.25 times the 
mass of the reciprocating member times the velocity squared of crankpin 
center 52. It is important to note that the energy is unchanging in 
equation 18. The terms combine such that the energy is constant throughout 
the stroke thus eliminating the transfer of energy back and forth between 
crank 14 and reciprocating member 10/connector 14. 
The combined energy of connector 14 and the reciprocating member 10 in FIG. 
12 remains constant throughout the entire stroke. This is best seen in 
equation 19, where again E is energy, M is mass, V is velocity, Mr is the 
mass of reciprocating member 10, Vr is the velocity of reciprocating 
member 10, Mc is the mass of connector 14, Vc is the velocity of the 
connector center of mass 56, [Vcp] is the non directional magnitude of the 
velocity of crankpin 
Equation 17 
EQU E=1/2MV.sup.2 =1/2MrVr.sup.2 +1/2McV.sup.2 =1/2Mr*[(2[Vcp]*(-sin 
theta)].sup.2 +1/2Mc*([(0.5[Vcp])*(-sin theta)].sup.2 +[1.5[Vcp])*(cos 
theta)].sup.2) 
Equation 18 
EQU E=2Mr*[Vcp].sup.2 *(-sin theta).sup.2 +0.25Mr*[Vcp].sup.2 *(-sin 
theta).sup.2 +2.25Mr*[Vcp].sup.2 * (cos theta).sup.2 =2.25Mr*[Vcp].sup.2 
*[(-sin theta).sup.2 +(cos theta).sup.2 ]=2.25Mr *Vcp.sup.2 
center 52, (2[Vcp]*(-sin theta) is the velocity of reciprocating member 10 
in the direction of reciprocation. Also, (-1[Vcp])*(-sin theta) is the 
velocity of the connector center of mass 56 in the direction of 
reciprocation 53 and (3[Vcp])*(cos theta) is the velocity of the connector 
center of mass 56 in the direction perpendicular to the axis of 
reciprocation 53. 
The resulting energy of reciprocating member 10 and connector 14, for FIGS. 
12a -12d where the mass of connector 14 is one half that of reciprocating 
member 10 and where the distance from crankpin center 52 of the connector 
center of mass 56 is twice the distance from crankpin center 52 to the 
center of connector rotation 54 (crankpin offset), is again 2.25 times the 
mass of reciprocating member 10 times the velocity squared of crankpin 
center 52. The resultant energy will not always be 2.25 times the mass of 
reciprocating member 10 times the velocity squared of crankpin center 52 
as is in the case in both equations 18 and 20. Different ratios of the 
mass of connector 14 of the mass of reciprocating member 10 will result in 
different energies. 
Equation 19 
EQU E=1/2MV.sup.2 =1/2MrVr.sup.2 +1/2McV.sup.2 =1/2Mr*[(2[Vcp]*(-sin 
theta)].sup.2 +1/2Mc*([(-1[Vcp])*(-sin theta)].sup.2 +[(3[Vcp])*(cos 
theta)].sup.2) 
Equation 20 
EQU E=2Mr*[Vcp].sup.2 *(-sin theta).sup.2 +0.25Mr*[Vcp].sup.2 *(-sin 
theta).sup.2 +2.25Mr*[Vcp].sup.2 *(cos theta).sup.2 =2.25Mr*[Vcp}.sup.2 
*[(-sin theta).sup.2 +(cos theta).sup.2 ]2.25Mr*Vcp.sup.2 
In the special case described by FIGS. 1-7 and 8a-8f the energy is 2 times 
the mass of reciprocating member 10 times the velocity squared of crankpin 
center 52. The energy is unchanging in equation 20. The terms combine such 
that the energy is constant throughout the stroke thus eliminating the 
transfer of energy back and forth between crank 14 and the reciprocating 
member 10/connector 14. 
To aid in visualizing the motion of the 3 conditions, as illustrated in 
FIGS. 8a-8f, FIGS. 11a-11d and FIGS. 12a-12d, imagine: (1) a crankpin 
rotating around a crank center with an angular velocity in a direction of 
rotation; (2) the connector and the reciprocating member as points masses 
both on a line passing through the crankpin center where the line is 
rotating with an angular velocity equal but in a direction opposite that 
of the crankpin center; and (3) the distance from the crankpin center to 
the point mass of the reciprocating member to be equal to the crankpin 
offset and that the point mass of the reciprocating member is confined to 
straight line motion passing through the crank center while it rotates 
around the crankpin with an angular velocity equal to but in a direction 
opposite that of the crankpin around the crank center. 
The above hypothetical situation may be applied to all three cases. In case 
1, if the point masses of the connector and the reciprocating member are 
equal and their distances from the crankpin center are equal to the 
crankpin offset, the case is illustrated in FIGS. 8a-8f. The magnitude of 
the angular momentum and the kinetic energy must remain constant since the 
center of mass of the connector and the reciprocating member coincides 
with the crankpin center. 
In a second case, as illustrated in FIGS. 11a-11d (1) the point mass of the 
connector is greater than the point mass of the reciprocating member; and 
(2) the distance from the crankpin to the point mass of the connector is 
equal to the crankpin offset times the mass of the reciprocating member 
divided by the mass of the connector. The magnitude of the angular 
momentum and the kinetic energy must remain constant since the a center of 
mass of the connector and the reciprocating member coincides with the 
crankpin center and the motion of the point mass of the connector travels 
in an ellipse with angular direction the same as the crankpin since the 
distance from the crankpin center to the point mass of the connector is 
less than one crankpin offset. The major axis is perpendicular to the line 
to which the point mass of the reciprocating member is confined. 
In a third case, as illustrated in FIGS. 12a-12d (1) the point mass of the 
connector is less than the point mass of the reciprocating member; and (2) 
the distance from the crankpin to the point mass of the connector is equal 
to the crankpin offset times the mass of the reciprocating member divided 
by the mass of the connector. In this case, the magnitude of the angular 
momentum and the kinetic energy must remain constant since the center of 
mass of the connector and the reciprocating member coincides with the 
crankpin center and the motion of the point mass of the connector will 
travel in an ellipse with angular direction opposite as the crankpin since 
the distance from the crankpin center to the point mass of the connector 
is greater than one crankpin offset. The major axis is again perpendicular 
to the line to which the point mass of the reciprocating member is 
confined. 
The combined energy of the connector and the reciprocating member is the 
least for case 1 as described in FIGS. 1-7 and 8a-8f. However the 
magnitude of the combined momentums is the least for case 3 (FIGS. 
12a-12d) where the mass of the connector is less than the mass of the 
reciprocating member. Combined momentum and resulting frictional forces on 
the crankpin due to inertia will continue to drop as the mass of the 
connector decreases. However, due to structural design constraints, case 2 
(FIGS. 11a-11d) may be more typical although it is generally desirable to 
minimize the mass of the connector within those restraints. 
Mechanism 8, as described in FIG. 1 but expanded to cover FIGS. 11a-11d and 
12a-12d where the mass of reciprocating member 10 and connector 14 are not 
equal, can fully balanced by the addition of crank counterweights 62A and 
62B that late opposite crankpin center 52 on a line passing through 
crankpin center 52 and crank center 50 and that are sized to oppose the 
momentums of reciprocating member 10 and connector 14 whose primary 
momentums are perpendicular and 90 degrees out of phase with each other 
and when combined act centrally on crankpin center 52 with constant 
momentum that is equal to the combined mass of reciprocating member 10 and 
the connector 14 times the directional velocity of crankpin center 52. 
In the specific subset where the mass of reciprocating member 10 equals the 
mass of connector 14, the momentum of crank counterweights 62A and 62B is 
twice the mass of reciprocating member 10 times the directional velocity 
of crankpin center 52 as shown earlier in Equation 10. However, in FIGS. 
11a-11d and 12a-12d the masses of reciprocating member 10 and connector 14 
are no longer equal and the required momentum of crank counterweights 62A 
and 62B to fully balance mechanism 8 will be equal to the combined masses 
of reciprocating member 10 and the connector 14 times the directional 
velocity of crankpin center 52. 
As described earlier in connection with FIGS. 11a-11d, the magnitude of the 
combined momentum of reciprocating member 10 and connector 14 was three 
times the mass of reciprocating member 10 times the velocity of the 
crankpin center 52 with a combined directional momentum of three times the 
mass of reciprocating member 10 times the velocity of crankpin center 52. 
This may be best see from earlier equations 13 and 12. In equation 13, 
P=Mr*(3[Vcp]), and in equation 12, P=Mr*(3[Vcp]*(-sin theta+cos theta) 
where the magnitude of the momentum remains unchanged throughout the 
stroke and in a direction of the velocity of crankpin center 52. Again, P 
is momentum, Mr is the mass of reciprocating member 10, and [Vcp] is the 
absolute velocity of the crankpin center 52. The direction of the velocity 
of crankpin center 52 and the direction of the combined momentum of 
reciprocating member 10 and connector 14 is given by the (-sin theta +cos 
theta) term 
Mechanism 8 can be fully balanced by the addition of crank counterweights 
62A and 62B to crank assembly 12 that have the same absolute momentum as 
the combined translational momentum of reciprocating member 10 and 
connector 14 and that have an orientation opposite crank center 50 as is 
crankpin center 52. Crank counterweights 62A and 62B have momentums shown 
in equation 21 where P.sub.cc is the momentum, M.sub.cc is the mass, and 
V.sub.cc is the velocity of the crank counterweights 62A and 62B. 
As described earlier in connection with FIGS. 12a-12d, the magnitude of the 
combined momentum of reciprocating member 10 and connector 14 was 1.5 
times the mass of reciprocating member 10 times the velocity of the 
crankpin center 52 with a combined directional momentum of 1.5 times the 
mass of reciprocating member 10 times the velocity of crankpin center 52. 
This may be understood from earlier equations 16 and 15, since in equation 
16, P=Mr*(1.5[Vcp]), and in equation 15, P=Mr*(1.5[Vcp]*(-sin theta+cos 
theta) where the magnitude of the momentum remains unchanged throughout 
the stroke and in a direction of the velocity of crankpin center 52, P is 
momentum, Mr is the mass of reciprocating member 10, and [Vcp] is the 
absolute velocity of the crankpin center 52. The direction of the velocity 
of crankpin center 52 and the direction of the combined momentum of 
reciprocating member 10 and connector 14 is given by the (-sin theta+cos 
theta) term. 
Mechanism 8 can be fully balanced by the addition of crank counterweights 
62A and 62B to crank assembly 12 that have the same absolute momentum as 
the combined translational momentum of reciprocating member 10 and 
connector 14 and that have an orientation opposite crank center 50 as is 
crankpin center 52. Crank counterweights 62A and 62B have momentums shown 
in equation 22 where P.sub.cc is the momentum, M.sub.cc is the mass, and 
V.sub.cc is the velocity of the crank counterweights 62A and 62B. 
The inertia forces of crank counterweights 62A and 62B are thus outward 
from crank center 50 in a direction opposite crankpin center 52 and are of 
Equation 21 
EQU P.sub.cc =M.sub.cc *V.sub.cc =-M.sub.r *(3V.sub.cp)=-P 
Equation 22 
EQU P.sub.cc =M.sub.cc *V.sub.cc =-M.sub.r *(1.5V.sub.cp)=-P 
equal magnitude of the combined translational inertia forces of 
reciprocating member 10 and connector 14. The outward (centrifugal) 
inertia forces of crank counterweights 62A and 62B thus oppose the 
translational inertia forces of connector 14 at midstroke in both 
directions and opposes the combined translational forces of reciprocating 
member 10 and connector 14 at the ends of the stroke and between midstroke 
and the ends of the stroke. However, the size of crank counterweights 62A 
and 62B are different compared to reciprocating member 10 as seen from 
equations 10, 21, and 22. 
The size of crank counterweights 62A and 62B will decrease as the mass of 
connector 14 relative to the mass of reciprocating member 10 decreases. It 
is thus desirable to reduce the mass of connector 14 to further minimize 
frictional forces, but this is design limited. The connector can 
physically be reduced in size only so much. Also, to eliminate the 
transfer of energy back and forth from crank 12, the distance from the 
connector center of mass 56 to crankpin center 52 is equal to the distance 
from the center of connector rotation 54 to crankpin center 52 (crankpin 
offset) in the opposite direction times the mass of reciprocating member 
10 divided by the mass of connector 14. 
It is to be understood that the novel use of connector counterweights can 
be practiced other than specifically described to eliminate or to reduce 
the transfer of energy back and forth between the crank and the 
reciprocating member. One example would be the use of counterweights to 
achieve connector motion in the form of an ellipse perpendicular to the 
axis of reciprocation where the mass of the connector 14 does not equal 
the mass of reciprocating member assembly 10 times the distance from the 
crankpin center 52 to the center of connector rotation 54 (the crankpin 
offset) divided by the distance from the crankpin center 52 to the 
connector center of mass 56 in the opposite direction. This arrangement 
may purposely be used to allow some transfer of energy back and forth 
between the crank 14 and reciprocating member 10 to help reduce 
fluctuations in angular crank velocity in low to medium high speed 
mechanisms under high external loads on the reciprocating member. 
Generally, the distance from crankpin center 52 to the connector center of 
mass 56 would be limited to value between about 0.5 and 2 times the 
distance of crankpin center 52 to the center of connector rotation 54 
times the mass of reciprocating member 10 divided by the mass of connector 
14 and connector center of mass 56 would be in a direction opposite 
crankpin 52 as is the center of connector rotation 54. 
Although a preferred embodiment of the invention is described with some 
particularity, many modifications and variation of the preferred 
embodiment may be made without deviating from the invention. Accordingly, 
it is to be understood that, within the scope of the appended claims, the 
invention may be practiced other than as specifically described.