Note: Descriptions are shown in the official language in which they were submitted.
CA 02569781 2006-12-01
VALVE LIFTING ARRANGEMENT
FIELD OF THE INVENTION
The present invention pertains to valve actuating mechanisms for internal
combustion engines, and more particularly pertains to a valve actuating
mechanism
wherein the valve is opened and closed through positive force.
BACKGROUND OF THE INVENTION
Most automotive engines have at least two valves for each cylinder, one intake
and one exhaust valve. Since each of these valves operates at different times,
separate
operating mechanisms must be provided for each valve. Valves are normally held
closed
by heavy springs and by compression in the combustion chamber. The purpose of
any
valve-actuating mechanism is to overcome the spring pressure and open the
valves at the
proper time. The valve-actuating mechanism includes the engine camshaft, the
camshaft
followers (valve lifters or tappets), pushrods, and rocker arms.
Among the prior art patents that disclose valve operating assemblies and
mechanisms are the following: Granz 1,118,411; Moore 1,238,175; Reynolds
1,309,339;
Nibbs 1,684,407; Murray 2,122,484; Irving 2,244,706; Bailey 2,858,818; and
Folino
2004/0055552 Al.
SUMMARY OF THE INVENTION
The present invention comprehends a valve actuating assembly or mechanism for
an internal combustion engine that includes a valve lifter having a roller
rotatably
mounted at the lower end of the lifter. A plurality of rotary cam guides are
mounted on
the camshaft with one pair of cam guides oppositely mounted to each valve
lifter. Each
cam guide includes an elliptical or oblong-shaped roller track or channel and
the roller
channels for each pair of cam guides are of equivalent dimensions. A cam is
mounted on
the camshaft between the cam guides, and the lowermost end of the lifter is
defined by an
arcuate undersurface or radius that is engaged by the cam during certain
phases of the
engine cycle. The opposed ends of the roller fit within each respective roller
channel of
each cam guide so that the roller is simultaneously engaged at both opposed
ends by the
outer surfaces of the roller channels during certain phases of the engine
cycle.
The lifter is actuated through the engagement of the roller ends with the
outer
surfaces of the roller channels during the rotation of the cam guides on the
camshaft.
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CA 02569781 2006-12-01
Moreover, the lifter is interconnected to a connecting rod, and actuation of
the lifter
causes a rocker arm pivotally attached at one end to the connecting rod to
open and close
the valve with positive force. During those phases when the valve is closed a
light valve
spring that is disposed immediately above - and contained between - the end of
the
rocker arm that interconnects to the valve extension of the valve and a
retainer
compresses approximately 1/16 of an inch or with a force of roughly 60 pounds
for
preventing the valve from inadvertently opening and to provide for expansion
and
contraction resulting from temperature changes. Thus, the positive force
required to open
and close the valve of the present invention is approximately 10 per cent of
that currently
in use wherein approximately 200 pounds of force per valve are required for
opening and
closing.
It is an objective of the present invention to provide a valve actuating
assembly
for an automotive engine that uses a positive force to open and close the
valves of the
engine.
It is another objective of the present invention to provide a valve actuating
assembly for an automotive engine wherein the valve spring for each valve
provides for a
positive closure of the cylinder port.
It is yet another objective of the present invention to provide a valve
actuating
assembly for an automotive engine wherein the release of the valve spring
initiates the
movement of the valve ahead of the rotation of the cam thereby reducing wear
on the
lifter.
Yet another objective of the present invention is to provide a valve actuating
assembly for an automotive engine wherein the release of the pressure of the
valve spring
actually sets the weight of the valve assembly in motion for completing
various phases of
the engine cycle.
Yet still another objective of the present invention is to provide a valve
actuating
assembly for an automotive engine wherein the contact point continuously
shifts from
between the bottom radius of the lifter to the roller for initiating valve
opening and
closing during the various engine cycles.
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CA 02569781 2006-12-01
T'hese and other objects, features and advantages will become apparent to
those
skilled in the art upon a perusal of the following detailed description read
in conjunction
with the drawing figures and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE I is a perspective view of the valve actuating assembly of the present
invention illustrating the interconnection of the lifter with the channels of
the rotary cam
guides;
FIGURE 2 is a perspective view of the valve actuating assembly of the present
invention illustrating the cam guides and the radius and roller at the lower
end of the
lifter;
FIGURE 3 is a sectioned view of the valve actuating assembly of the present
invention illustrating all the primary components of the valve actuating
assembly at a
particular piston stroke of the engine cycle;
FIGURE 4 is a side elevational view of the valve actuating assembly of the
present invention illustrating the disposition of the cam enclosed between the
rotary cam
guides;
FIGURE 5 is a sectioned elevational view of the valve actuating assembly of
the
present invention taken along lines 5 - 5 of figure 4 illustrating the
disposition of the cam
relative to the channel of the rotary cam guide;
FIGURE 6 is a side elevational view of the valve actuating assembly of the
present invention illustrating the valve lifter and the radius and roller
extending through
the lower end of the lifter;
FIGURE 7 is a side elevational view of the valve actuating assembly of the
present invention illustrating the internal fluid chamber extending through
the lifter and
the bearing supports for the roller;
FIGURE 8 is a side elevational view of the valve actuating assembly of the
present invention illustrating the seating of the rollers within the channel
of one rotary
cam guide;
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FIGURE 9 is a side elevational view of the valve actuating assembly of the
present invention illustrating the valve actuating assembly in the climbing
disposition for
actuating the valve to open the port;
FIGURE 10 is a side elevational view of the valve actuating assembly of the
present invention illustrating the valve assembly in the peaked position
whereupon the
valve has fully opened the port;
FIGURE 11 is a side elevational view of the valve actuating assembly of the
present invention illustrating the valve assembly in the descending position
for actuating
the valve to close the port;
FIGURE 12 is a side elevational view of the valve actuating assembly of the
present invention illustrating the valve assembly in the fully descended
position
whereupon the valve has completely closed the port; and,
FIGURE 13 is a sectioned elevational view of the valve actuating assembly of
the
present illustrating the degrees of rotation of the cam guides and cam during
the various
engine phases.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Illustrated in Figures 1 through 13 is a mechanical arrangement or mechanism
for
raising and lowering the valves of an internal combustion engine; and
specifically the
internal combustion engine of an automotive vehicle. The valve lifting
arrangement 10
of the present invention is most suitably adapted for a four stroke cycle
engine, and
particularly a four stroke cycle engine of the I-head or overhead valve
construction.
However, it would be possible to adapt the valve lifting arrangement 10 of the
present
invention for the type of engine known as an F-head engine.
Figures 3 and 9 through 12 illustrate for representative purposes a portion of
a
cylinder head 12 having a rocker arm mounting block. An upper end or head 16
of a
cylinder 18 is shown, and a representative port 20 is shown in communication
with
cylinder 18 for allowing the ingress and egress of the air and fuel mixture
and the
evacuation of the exhaust gases during the various piston strokes (intake,
compression,
power and exhaust) that comprise the reciprocating piston movements of a four
cycle
engine. A representative valve 22 is shown that includes a valve stem 24 and
the
reciprocable movement of valve 22 results in the opening and closing of port
20 of
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cylinder 18 coincident with the reciprocable strokes of the piston. Valve stem
24
includes an upper valve stem extension 26 that projects slightly past cylinder
head 16,
and all the components of valve lifting arrangement 10 are enclosed within a
standard
cylinder head cover (not shown). Valve stem extension 26 provides a shoulder
for a
rocker arm to push against. Figures 1 and 2 illustrate a portion of a camshaft
28 that is
enclosed within and extends through the engine block (not shown).
Illustrated in Figures 1 through 5 and 8 through 12 are a pair of rotary cam
halves
or guides 30 that are spaced or separated from each other and are mounted on
camshaft
28 for coincident rotation with camshaft 28. In the preferred embodiment cam
guides 30
are disc-shaped but they can also be in the shape of squares, rectangles,
triangles, etc., so
long as they can be mounted on camshaft 28 and accommodated within the engine
block.
Each cam guide 30 includes an inwardly opening roller track or channel 32, and
roller
channels 32 are equal in dimensions and thus mirror each other in depth and
shape. The
shape of each roller channel 32 is not circular, but is of an elongated oblong
or elliptical
shape; but in any case, the shape of each roller channel 32 should complement
or mirror
the other roller channel 32. However, each roller channel 32 is continuously
uniform in
width and depth as shown most clearly in Figures 4 and 5; but they cannot be
circular in
shape. Each rotary cam guide 30 is further defined by an interior intermediate
portion 34,
and each intermediate portion 34 is eccentrically mounted relative to camshaft
28 and
also has an elongated shape. Mounted on camshaft 28 and in between the
separation of
each cam guide 30 is a cam 36 that rotates concomitant with cam guides 30 and
with
camshaft 28. Cam 36 also has an elliptical or elongated shape, and cam 36 is
shaped
similar to each adjacent intermediate portion 34 but cam 36 is smaller in size
than each
intermediate portion 34. Thus, cam 36 never extends beyond each intermediate
portion
34 during its rotation on camshaft 28, or, alternatively, cam 36 doesn't
extend into roller
channels 32. Cam 36 includes a lobe 38 and an opposite flat or stepped portion
40, and
the exterior of cam 36 defines a cam surface 42. In addition, each roller
channel 32
includes an outer surface or race 44 and an opposite inner surface or race 46,
and the
separation or distance of surfaces 44 and 46 from each other defines the width
of each
roller channel 32. Cam guides 30, roller channels 32, and cam 36 are coaxially
mounted
on camshaft 28 and are timed to rotate as a unit.
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CA 02569781 2006-12-01
Illustrated in Figures 1 through 3 and 6 through 8 is a valve tappet or lifter
48 for
transmitting the rotational motion of camshaft 28 into reciprocating motion
for raising
and lowering valve 22 and thereby uncovering and covering cylinder port 20 as
part of
the engine piston strokes or cycles. Valve lifter 48 includes a lifter body 50
and a
generally square lifter head 52. Square lifter head 52 has increased surface
area for
providing a longer life for lifter 48. Valve lifter 48 includes a cylindrical
stem 54 that
allows lifter 48 to be turned and rotated for inserting lifter 48 between cam
guides 30.
The lower end of stem 54 of lifter 48 includes a roller aperture 56 that
transversely
extends through stem 54. Lifter 48, and more specifically the lower end of
stem 54,
includes a square-shaped foot 58, and foot 58 includes an arcuate undersurface
or radius
60 that interacts with cam 36 during certain piston strokes of the engine
cycle. Lifter 48
includes an upper lifter end 62, and upper lifter end 62 includes at least one
pair of
opposed alignment flats 64. Upper end 62 terminates with an internally
threaded
cylindrical portion 66. A retaining clip is placed on alignment flats 64 to
maintain the
orientation of lifter 48 between cam guides 30. Lifter body 50 also includes
at least one
oil groove 68 that circumscribes lifter body 50 and several ports 70, at least
one of which
is located in communication with oil groove 68. Ports 70 register with an
internal
chamber 72 that extends the length of lifter body 50. Chamber 72 narrows to,
and
registers with, a passageway 74 that extends through stem 54 whereupon
passageway 74
registers with roller aperture 56 for allowing the conveyance of oil or other
lubricants
through chamber 72 and passageway 74 and thence into roller aperture 56 for
lubrication
of a roller 76 disposed therein.
As shown in Figures 6 through 8, roller 76 is inserted through roller aperture
56
with projecting ends 78 of roller 76 being received and contained within each
roller
channe132. The insertion of ends 78 of roller 76 into each roller channel 32
of each cam
guide 30 allows roller 76 to roll easier as a generally equal amount of drag
is distributed
on both sides of lifter 48 adjacent foot 58 of stem 54. The disposition of
roller ends 78
within roller channels 32 also tends to orient lifter 48 between cam guides 30
without the
need to use the lifter retainer clip. Roller ends 78 travel within channels 32
continuously
throughout the rotation of rotary cam guides 30 on camshaft 28. Disposed
within the
lower end of stem 54 of lifter 48 and circumjacent roller 76 is a plurality of
needle
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CA 02569781 2006-12-01
bearings 80. Needle bearings 80 extend transversely through stem 54 and
provide a
bearing surface for roller 76 to facilitate the rotation of roller 76 during
the various piston
strokes. Needle bearings 80 are enclosed within an inner shell or housing that
is outboard
and circumjacent roller 76 and roller aperture 56. Valve lifter 48 must be
rotated 90
degrees to fit through the slot or gap 82 formed between cam guides 82, and
then rotated
90 degrees again to insert roller ends 78 into the respective roller channels
32, as shown
in Figures 6 through 8, so that roller ends 78 can seat within and selectively
engage outer
surfaces 44 of roller channels 32 of cam guides 30. After insertion of roller
ends 78 in
roller channels 32, the retaining clip is placed over flats 64 at upper end 62
of lifter 48.
One or more 0-rings 84 can be used for an oil seal as shown in Figure 6.
As shown in Figures 1 through 12, a connecting or push rod 86, preferably
composed of carbon steel, is attached to upper end 62 of valve lifter 48.
Lower end 88 of
connecting rod 86 includes external threads 90 that engage the internal
threads of
cylindrical portion 66 thereby allowing for the selective linear adjustment of
connecting
rod 86. Varying the length of connecting rod 86 allows for variation in the
amount or
length of travel of valve 22 and thus allows for the variation in the time
required for
covering and uncovering port 20. At least one lock nut 92 is used to secure
connecting
rod 86 in position with respect to upper end 62 of lifter 48. Upper end 94 of
connecting
rod 86 (which may be threaded) attaches to a rocker arm 96 at a swivel joint.
More
specifically, the swivel joint includes hardened swivel joint pin 98 that
extends through
upper end 94 of connecting rod 86 and rocker arm 96 for making the pivotal
connection
therewith. Rocker arm 96 can be pivotally mounted to a rocker arm shaft
bracket; or, as
shown in the present invention rocker arm 96 is pivotally mounted to a rocker
arm
mounting block 100 by a hardened rocker arm pivot pin 102. Rocker arm 96
transfers
motion from connecting rod 86 to valve 22. Rocker arm 96 includes a thinner
tapered
end 104 that is machined to accept or be attached to valve stem extension 26.
Tapered
end 104 of rocker arm 96 moves with valve stem extension 26 during the piston
strokes
that comprise the four cycle engine. In addition, it should be noted that the
distance
between or from swivel joint pin 98 to rocker arm pivot pin 102 is closer or
less than the
distance between rocker arm pivot pin 102 and the point where tapered end 104
of rocker
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CA 02569781 2006-12-01
arm 96 connects or attaches to valve stem extension 26. This provides for a
more precise
timing in the opening and closing of port 20.
As illustrated in Figures 9 through 12, valve stem extension 26 includes a
medium
duty valve spring 106 rated at approximately 60 pounds of force at 1/16 of an
inch travel
between the spring relaxed state and the spring compressed state or, in known
in the
alternative as the valve compression state. Valve spring 106 is contained
between a
lower retainer 108 and an upper retainer 110, and valve spring 106 provides
for a positive
closure of port 22 as will be hereinafter further described. In addition, the
release of
valve spring 106 during certain parts of the piston stroke actually transmits
motion to
rocker arm 96 and lifter 48 for generating valve 22 movements. Lower retainer
108 is
pushed upward during certain parts of the piston stroke. Moreover, valve
spring 106 only
holds valve 22 in place in the closed position; valve spring 106 doesn't
actually pull on
valve 22 and thus only positive force is exerted on valve 22 by spring 106
during certain
piston strokes. Disposed on valve stem extension 26 below lower retainer 108
is a belled
spring washer or cupped washer 112 that acts as a wearing surface. Cupped
washer 112
softens impact and absorbs shock from the continuous direction change of
rocker arm 96
relative to valve stem extension 26. A second lower retainer can be placed on
valve stem
extension 26 immediately below cupped washer 112 to further support and
maintain the
position of cupped washer 112 on valve stem extension 26. Cupped washer 112
and
lower retainer 108 move with valve stem extension 26 coincident with the
movement of
rocker arm 96 and valve 22 for covering and uncovering port 20 during the
respective
piston strokes. All of the aforementioned components can also be referred to
as the valve
assembly or valve actuating mechanism.
The raising and lowering of valve 22 to open and close port 20 coincident with
the various piston strokes is a result of the interaction of radius 60 of
lifter 48 with cam
surface 42 of cam 36 and the engagement of roller ends 78 of roller 76 with
outer surface
44 of roller channel 32. Depending on the particular piston stroke, one or the
other of the
above interactions and engagements is occurring for initiating the opening or
closing of
port 22. In other words, mechanical contact is continuously transferred
between roller
ends 78 with outer surfaces 44 of channels 32, and radius 60 of lifter 48 with
cam surface
42, throughout the rotation of camshaft 28 and corresponding piston strokes.
However, it
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CA 02569781 2006-12-01
doesn't occur for any piston stroke that positive force is exerted by both the
engagement
of roller ends 78 with outer surfaces 44, and by the contact of radius 60 with
cam surface
42 of cain 36. With reference to Figures 9 through 12, the movements can be
described
relative to the reciprocable upward or downward movement of lifter 48 and
connecting
rod 86 so that Figure 9 illustrates lifter 48 and connecting rod 86 in the
climbing
disposition or state, Figure 10 illustrates lifter 48 and connecting rod 86 in
the fully
extended or peaked state, Figure 11 illustrates connecting rod 86 and lifter
48 in the
descending state, and Figure 12 illustrates connecting rod 86 and lifter 48 in
the fully
descended state. The directional arrows in Figures 9 through 12 indicate the
rotational
direction of camshaft 28, cam guides 30, roller channels 32, and cam 36.
Thus, Figure 9 shows the valve assembly just prior to and commencing the
opening of port 20. The pressure of valve spring 106 is released and there is
no load on
roller 76 or radius 60 of lifter 48 although cam surface 42 is in contact -
momentarily -
with radius 60 of lifter 48. It should be noted that the release of valve
spring 106
pressure actually sets the weight of valve 22 in motion. As camshaft 28
rotates from the
position shown in Figure 9 to the position shown in Figure 10, the engagement
of cam
surface 42 with radius 60 transmits upward movement to lifter 48 and
connecting rod 86
thereby initiating the pushing open of valve 22. However, no valve spring 106
pressure
is being exerted, and the only load is the weight of the entire valve
assembly. In addition,
there is a very slight clearance between roller ends 78 and outer surfaces 44
of both roller
channels 32. Simultaneous with camshaft 28 rotation connecting rod 86 attains
the
peaked state causing valve 22 to move to the fully open state. There is no
valve spring
106 pressure being exerted in valve 22 full open state nor is any valve weight
or load
being exerted. However, the contact point is shifting from the interaction
between cam
surface 42 and radius 60 of lifter 48 to the engagement of roller ends 78 with
outer
surfaces 44 of the roller channels. These contact points only shift
approximately .003 to
.006 of an inch. Figure 10 illustrates maximum valve 22 opening, and in this
position
there is no load on the valve assembly, no valve spring 106 is being exerted,
and no valve
22 weight on the assembly. Roller ends 76 are not in contact with outer
surfaces 44 of
roller channels 32.
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CA 02569781 2006-12-01
As camshaft 28 rotates from the peaked position of Figure 10, wherein valve 22
is
fully open, to the descending position of Figure 11 for initiating valve 22
closure of port
20, a number of mechanical actions simultaneously occur that raise valve 22
and close
port 20. The contact point shifts from between radius 60 and lifter 48 to
roller 76 through
the rotation and contact of outer surfaces 44 with roller ends 78 of roller
76.
Momentarily there is still no valve spring 106 pressure as the rotational
contact of outer
surfaces 44 with roller 76 starts to pull downward on lifter 48 and connecting
rod 86. As
this action occurs a clearance gap results between cam surface 42 and radius
60 of lifter
48. The clearance gap can be between .003 and .006 inches. As camshaft 28
continues
its rotation from the position shown in Figure 10 to that of Figure 11, outer
surfaces 44 of
roller channels 32 continue to engage roller ends 76 and pull roller 76
downward - and
thus pull downward lifter 48 and connecting rod 86. Thus, as cam guides 30
rotate to the
descending position of Figure 11, outer surfaces 44 continue to pull down on
roller ends
76 coincident with the rotation of roller channels 32 thereby continuing to
pull downward
on lifter 48 and connecting rod 86. Throughout these actions rocker arm 96 is
pivoting
and this results in upper retainer 110 starting to compress valve spring 106.
As camshaft
28 continues its rotation from the position of Figure 11 to the position shown
in Figure
12, the mechanical interaction between roller ends 76 and outer surfaces 44 of
roller
channels 32 is transmitted through lifter 48, connecting rod 86, and rocker
arm 96 thereby
for raising valve 22 and seating valve 22 against port 20 so that port 20 is
closed. Roller
ends 78 have maintained contact with outer surfaces 44 of roller channels 32
and the
interaction of roller ends 76 with outer surfaces 44 of roller channels 32
has, in effect,
pulled valve 22 shut. In addition, the clearance gap of between approximately
.003 - .006
is maintained between radius 60 of lifter 48 and cam surface 42. There is no
valve spring
pressure 106 being exerted, only the weight of the valve assembly. Valve 22
can be fully
seated under approximately 60 to 80 pounds of load by the use of a 1/32 of an
inch to a
1/16 of an inch compression of valve spring 106. It should be noted that at no
time
during the various piston strokes is positive force applied to either close or
open valve 22
through both the combined and simultaneous mechanical interactions of roller
76
interacting with outer surfaces 44 and radius 60 of lifter 48 contacting cam
surface 42.
This feature allows the use of medium duty spring 106 having approximately 60
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CA 02569781 2006-12-01
of force instead of a standard heavy-duty spring having approximately 200
pounds of
force. When valve 22 is raised to close port 20, roller 76 is under load
through the
engagement with outer races 44 of cam guides 30; when valve 22 is lowered to
open port
20, roller 76 is not under load as roller 76 has disengaged from contact with
outer races
44 of cam guides 30.
Figures 9 through 12 illustrate one complete cycle of the engine, and the next
cycle begins with the rotation of camshaft 28 to reach the climbing position
as shown in
Figure 9. During one complete engine cycle, contact is thus transferred
between roller
ends 78 of roller 76 and radius 60 of lifter 48. The degrees of rotation of
rotary cam
guides 30 and cam 36 for each piston stroke position are shown in Figure 13.
Valve 22 is
held closed throughout an approximately 250 degree rotation of cam guides 30,
roller
channels 32, and cam 36; valve 22 is being closed throughout a rotation of
approximately
20 degrees of rotation of the aforesaid components; valve 22 is held open
throughout an
approximately 70 degree rotation of the aforesaid components; and valve 22 is
being
opened throughout an approximately 20 degree rotation of the aforesaid
components.
To recapitulate the various mechanical interactions that occurs during the
piston
strokes, in the first phase valve 22 is opened by the engagement of roller
ends 78 with
outer surfaces 44 of channels 32 of the opposed cam guides 30 concomitant with
the
rotation of camshaft 28, and then by radius 60 of lifter 48 being engaged by
cam 36. The
duration of this movement is approximately 20 degrees of rotation of camshaft
28 and
cam guides 30. This corresponds to the climbing disposition shown in Figure 9.
In the second phase of the engine or valve cycle, valve 22 is held open by
radius
60 of lifter 48 being in contact with the elongated portion of cam 36. The
duration of this
movement is approximately 70 degrees of rotation of camshaft 28 and cam guides
30.
This phase corresponds to the peaked disposition shown in Figure 10.
In the third phase of the engine or valve cycle, valve 22 is closing by the
rotational engagement of outer surfaces 44 of both channels 32 of both cam
guides 30
with roller ends 78 pulling lifter 48 and connecting rod 86 downward
concomitant with
the rotation of camshaft 28. The duration for this phase is approximately 20
degrees of
rotation of camshaft 28 and cam guides 30, and this phase corresponds to the
descending
disposition shown in Figure 11.
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CA 02569781 2006-12-01
Finally, valve 22 is disposed to the fully closed position through the
continued
engagement of roller ends 78 with outer surfaces 44 of both channels 32 of cam
guides 30
concomitant with the continued rotation of camshaft 28. The duration for this
phase is
for approximately 250 degrees of rotation of camshaft 28 and cam guides 30,
and
corresponds to the fully descended position shown in Figure 12.
While this invention has been described in conjunction with a preferred
embodiment, it will be obvious to those skilled in the art that numerous
modifications,
alterations, and variations may be made without departing from the spirit of
the invention
and the scope of the claims appended thereto.
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