Single pin rocker joint CVT chain

A rocker joint for a power transmission chain is formed from a single pin and an associated link aperture. The pin has a substantially flat front surface and a convex back surface, with the back surface being defined by a plurality of radii. The pin is received in the aperture of the link such that the front surface of the pin engages and rocks on the curved surface of the link aperture. The back surface of the pin is movable in the aperture of the links as the surfaces move relative to one another when the chain articulates.

BACKGROUND OF THE INVENTION 
Reference is made to U.S. application Ser. No. 07/778,402, filed Oct. 17, 
1991, to Philip J. Mott, entitled "Single Pin Rocker Joint Bushing Chain," 
now U.S. Pat. No. 5,192,253 which is related to the subject matter of the 
present application and is incorporated herein by reference. 
1. Field of the Invention 
The present invention relates generally to power transmission chains and 
particularly to an improved rocker joint for such chains. The rocker joint 
is formed from a single pin and an associated link aperture. The invention 
has application to power transmission chains of the silent chain variety, 
as well as power transmission chains for use with variable pulley 
transmissions (continuously variable transmissions). 
2. Description of the Prior Art 
Power transmission chains are widely used in the automotive industry. Such 
chains are used for engine timing drives as well as for the transfer of 
power from the engine to the transmission, the transfer of power in a 
transfer case, or the transfer of power within a transmission. Power 
transmission chains are also widely used in industrial applications. 
One type of power transmission chain is referred to as "silent chain". Such 
chain is formed of interleaved sets of inverted tooth links. A set or rank 
of links is assembled from several links positioned alongside of or 
laterally adjacent to each other. Each link has a body with a pair of 
spaced apertures and the apertures of one set of links are arranged and 
aligned with the apertures of the next adjacent set of interleaved links. 
The links have a pair of depending toes separated by a crotch. 
The links are connected by pivot means, which are typically round pins 
received in the link apertures. The pivot means can also comprise a rocker 
joint, which may include a pin and a rocker. Each pin and rocker has a 
front face which contact and rock on each other. An example of silent 
chain is found in U.S. Pat. No. 4,342,560, which is incorporated herein by 
reference. An example of silent chain which can be used in engine timing 
applications is found in U.S. Pat. No. 4,759,740, which is also 
incorporated herein by reference. 
A second type of power transmission chain is used to transfer power between 
a pair of variable pulleys in a continuously variable transmission. The 
chain links are provided in sets that are interleaved together. The links 
have aligned apertures for receiving pivot means. The pivot means can 
provide the means for the transfer of power between the chain and the 
sheaves of the pulley by allowing the sheaves to directly contact the ends 
of the pivot means in a driving engagement. 
Load blocks or load carrying means that are positioned on the chain between 
the spaced pivot members can also provide the means for transfer of power 
between the pulleys. The load blocks can be in the form of struts that are 
carried in a passageway below the links. Alternatively, the load blocks 
can extend around the links of the chain and have one or more windows for 
receiving the chain links therein. The load blocks have tapered outer or 
end surfaces which engage the sheave faces of the pulleys to provide the 
driving engagement between the pulleys and the chain. Examples of power 
transmission chains suitable for use in a continuously variable 
transmission are shown in U.S. Pat. No. 4,911,682, U.S. Pat. No. 
4,507,106, and U.S. Pat. No. 5,007,883, which are incorporated herein by 
reference. 
The present invention relates to an improved rocker joint for power 
transmission chain. Rocker joints for chains are known in the art. Rocker 
joints are utilized in an attempt to attain higher efficiencies and less 
wear than comparable round pin joints. Round pin joints typically produce 
higher wear as a result of the sliding action between the round pin and 
the inside of the circular link aperture, as the chain articulates. In 
contrast, rocker joints provide a lower wear joint on account of the 
rocking action between the pin and the rocker portion, as the chain 
articulates. 
U.S. Pat. No. 4,507,106 discloses a rocker joint in which, in the preferred 
embodiment, each pin or rocker has the identical cross-section. Each pin 
has a front surface which rocks on the front surface of the adjacent pin. 
In the preferred embodiment, the pins have a front surface defined by a 
first radius, and a back surface defined by a second and a third radius, 
both progressively smaller than the first radius. The rocker joint 
comprises a pair of pins fitted into each group of aligned apertures in 
the interleaved sets of links to join the links and permit articulation. 
U.S. Pat. No. 4,911,682 discloses a rocker joint that includes a pair of 
pins. The rocker joint has apertures that are a generally hour-glass shape 
with the enlarged ends receiving the pins. The front surfaces of the pins 
rock against one another, while the back surfaces of the pins are 
prevented from substantial rotation by the curvature of the apertures. 
These prior art patents represent examples of rocker joints utilizing two 
pivot members or pins, or a pin and a rocker. The present invention 
relates to single pin rocker joints in which a single pin rocks against 
the link aperture. U.S. Pat. No. 2,667,791 discloses a silent chain with a 
single pin rocker joint. The chain has a single pin with an arcuate 
periphery, defined by a single radius, and a relatively flat bearing 
surface. The link has a generally semi-circular aperture with an arcuate 
bearing surface. The flat surface of the pin rocks against the arcuate 
surface of the link aperture. 
Another type of single pin rocker joint is shown in U.S. Pat. No. 
4,337,057. The patent discloses a double unrolling hinge for a chain-belt 
for a variable pulley transmission. Both sides of the hinge pin contact 
the insides of the link apertures. 
U.S. Pat. No. 1,564,798 also discloses a single pin, double-edged rocking 
joint. The pin is thicker in the center section than at the top and 
bottom. The formation of the link aperture allows the sides of the pin to 
roll against the aperture sides of adjacent, interleaved links. 
The present invention provides an improved single pin rocker joint for a 
power transmission chain. The construction of the pin includes a 
substantially flat rocking surface and an arcuate surface formed of a 
plurality of radii. In the silent chain embodiment, a clearance between 
the back surface of the pin and the associated aperture permits movement 
of the pin with respect to the aperture. The chain includes inside links 
and guide links and has application in timing drives as well as drives for 
continuously variable transmissions. 
SUMMARY OF THE INVENTION 
In accordance with one embodiment of this invention, a power transmission 
chain is constructed of an assembly of links and pivot members. The chain 
includes a plurality of sets of guide links interleaved with sets of 
inside links. Each guide link and inside link has a pair of spaced 
apertures. To assemble the chain, the apertures of one link set are 
transversely aligned with one set of apertures of the next adjacent link 
set. 
The apertures are defined by a series of surfaces. The apertures within the 
guide links have at least one curved surface and the apertures within the 
inside links have a plurality of curved surfaces. 
Pivot members, in the form of pins, are fitted within the apertures of the 
links. The pins have a substantially flat front surface and a convex back 
surface. The pivot member back surface is defined by a first radius. The 
pivot members are press fit in the apertures of the guide links such that 
the pivot member back surface engages the curved surface defined by the 
guide link. The press fit prevents substantial rotation of the pin 
relative to the guide link. 
As a result of a minimal clearance between the back surface of the pin and 
the associated aperture of the inside links, the back surfaces of the 
pivot members are allowed to move freely within the apertures of the 
inside links of the chain. The front surface of the pivot member and a 
curved surface of the inside link aperture engage and rock on one another 
with a rolling type action. 
The apertures of the inside links are formed by a series of radii. The 
inside link apertures are rotated with respect to a horizontal centerline 
of the body of the link in order to provide a positive tilt angle. In 
contrast, the apertures of the guide links have a flat surface that 
matches the flat surface of the pin. The flat surfaces of the apertures of 
the guide links are perpendicular with respect to the horizontal 
centerline of the link as well as the pitch line of the link. The 
apertures of the inside links are formed and spaced to provide a pitch 
length that is greater than the pitch length of the guide links. 
The rocker Joint of the present invention may be used in an inverted tooth 
silent chain or in a power transmission chain for a continuously variable 
transmission. In the silent chain use, the inside links include a pair of 
depending teeth that are formed to contact a sprocket for driving of the 
chain. In the use for a continuously variable transmission, the links 
include load carrying members in the form of load blocks. The load blocks 
may extend around the links or through a passageway formed in the base of 
the links. Alternatively, the pins may contact the pulley sheaves to 
provide the power transfer. 
In the power transmission chain for the continuously variable transmission, 
the chain includes sets of guide links and sets of inside links. The 
inside links are links that are in the non-guide rows. The inside links 
are configured to rotate with respect to the pins. The sets of guide links 
include pairs of external or flanking guide links which are located on the 
outside of the rows or sets. The flanking guide links are preferably press 
fit on the pins. That is, the pins are fit within the apertures of the 
flanking guide links so that the pins do not rotate with respect to the 
flanking guide links. Additionally, the internal or non-flanking guide 
links may be press fit on the pins. In such a chain, the non-flanking 
guide links also have an aperture configured to match the cross-section of 
the pin and thus prevent rotation of the guide link with respect to the 
pin. Alternately, the internal guide links may have apertures that are 
configured to allow rotation of the link with respect to the pin. 
The rocker joint of the present invention, which is used in an inverted 
tooth (or silent) power transmission chain, may also be used with 
non-flanking guide links that are press fit. This inverted tooth chain 
embodiment of the present invention includes flanking and non-flanking 
(internal) guide links which have an aperture configured to match the 
configuration of the pivot member. In this embodiment, as well as in the 
embodiment for use with a continuously variable transmission, the number 
of links in the non-guide row preferably exceeds the number of links in 
the guide row. 
The use of guide links which are press fit or interference fit with the 
pins provides a link with increased fatigue strength, in comparison to a 
link which is not press fit. The use of fewer links in the guide row than 
in the non-guide (articulating) row reduces the contact stresses in the 
chain. 
The rocker joint of the present invention has use in a timing chain 
application of inverted tooth links that are laced in a block form. In 
such a construction, the inside links are substantially identical and 
placed side-by-side in a row to form a block. Rows or sets of such block 
laced inside links are preferably alternated with guide link rows. The 
sets with guide links do not contain any inside links. Similarly, the 
rocker joint can be used in a continuously variable transmission chain 
that is laced in block form. 
Use of the single pin rocker joint of the present invention provides 
several advantages over the use of a round pin chain. The rocker joint 
provides generally higher efficiencies than the round pin joint with lower 
wear. Moreover, the single pin rocker joint of the present invention 
presents advantages over the double-pin rocker Joint design of the prior 
art by its elimination of the additional pin.

DETAILED DESCRIPTION OF THE DRAWINGS 
Turning now to the drawings, FIG. 1 illustrates a portion of a power 
transmission chain generally at 10. The chain includes sets or rows of 
interleaved links. In the embodiment of FIG. 1, the chain includes guide 
link rows 12 interleaved with inside link rows 14. The guide link rows are 
comprised of external or flanking guide links 16, while the inside link 
rows are comprised of inside links 18. The guide links 16 are shown more 
clearly in FIG. 4 and the inside links are shown more clearly in FIG. 2. 
In the preferred silent chain embodiment, the sets of inside links are 
laced in blocks and the sets of guide links do not include inside links. 
The complete chain drive (not shown) includes an endlessly connected chain 
10 wrapped about at least a pair of sprockets. The sprockets are mounted 
on shafts, such as an engine crankshaft or engine camshaft. The sprockets 
may be of different diameters and may have a different number of 
differently shaped teeth. The chain and sprocket system can also include 
an idler sprocket. 
The rows or sets of links are formed of a plurality of links placed in 
side-by-side relationship. The links of the interleaved set are preferably 
alternated with the links of the first set. The adjacent sets of links are 
joined by pivot means 20, which are illustrated in FIG. 6 as pins with a 
flat front working surface and an arcuate back surface. The pivot means 
are received in aligned sets of apertures 22, 24, 26, 28. Each link 
preferably includes a pair of apertures located at opposite ends of the 
link. 
In the silent chain embodiments, the flanking guide links 16 maintain the 
lateral alignment of the chain on the sprockets. The flanking guide links 
are along the outside of the chain and have no driving engagement with the 
sprocket teeth. Thus, the guide links are distinguished from the inside 
links 18, or driving links, by their lack of sprocket tooth contacting 
members. An inside guide link without sprocket contacting teeth (not 
shown) may also be used in which case the sprocket is grooved to receive 
the inside guide link. The pivot means 20 is shaped for a press fit within 
the apertures 26, 28 of the guide links. In the silent chain embodiment, 
the pivot means is typically peened over to maintain the integrity of the 
chain assembly; however, other methods may be used if desirable. In the 
embodiments of the present invention which have applications with 
continuously variable transmissions (CVT), the guide links act to secure 
the pins. Flanking guide links are placed along the outside of the rows of 
the chain, While other guide links are press fit on the pins and placed on 
the inside of the rows of the chain. 
The guide links shown in FIG. 4, which lack sprocket tooth contacting 
members (inverted teeth), are known as flanking guide links. Pairs of 
flanking guide links are placed on the outside of the chain in the guide 
rows to maintain the chain on the sprockets. The non-guide rows, which do 
not have pairs of flanking guide links, have the inside links. The 
external or flanking guide links are not to be confused with internal or 
non-flanking guide links. The internal guide links are links that are 
present in the guide rows. In the silent chain embodiment, the internal 
guide links include pairs of inverted teeth that are adapted to contact 
the teeth of a sprocket. The internal or non-flanking guide links may also 
be press fit on the pins in the guide rows. In the CVT embodiment, the 
non-flanking guide links include depending tabs which act to form a 
passageway for a load block. 
In the case where the chain includes internal or non-flanking guide links, 
the non-flanking guide links may include apertures of the same 
configuration as the flanking guide links to provide the press fit on the 
pins. Thus, when the inside link of FIG. 2 is positioned in the guide row 
as a non-flanking guide link, the link 18 may have apertures 26, 28 of the 
configuration shown in FIGS. 4 and 5. 
The guide link 16 is illustrated in FIG. 4. The guide link 16 is defined by 
body portion 30 and end portions 32, 34. The guide link apertures have 
substantially flat surfaces 38, 40, which are both oriented toward the 
inside body portion 30 of the link. The back surfaces 42, 44 of the 
apertures are formed by radii 46, 48, which are struck from center points 
50, 52. The radii center points 50, 52 are preferably located between the 
apertures 26, 28, within the body portion of the link. The apertures each 
contain additional connecting arcs with connecting radii 54, 56, which are 
shown only for aperture 26. The pitch of the guide link is measured as the 
distance between the flat surfaces 38, 40 of the apertures, along the 
pitch line of the link. 
Inside links 18 are interleaved with the guide links 16. Link 18 is 
illustrated in FIG. 2 and is defined by a pair of spaced toes 58, 60. The 
toes are defined by inside flanks 62, 64 and outside flanks 66, 68. The 
apertures are defined by a plurality of arcs, which are more clearly shown 
in the detail of FIG. 3. The front surface 69 is formed by an arc of 
radius 70 which is struck from centerpoint 72. The back surface 73 is 
formed by an arc of radius 74 which is struck from centerpoint 76. The 
connecting surfaces 77 are formed by a plurality of arcs, such as the arc 
struck from radius 78. The radii centerpoints of the apertures of the 
inside link are preferably located on opposite sides of the apertures, 
toward the end portions 80, 82 of the link. 
The apertures of the inside links are each preferably symmetrical about a 
centerline. The centerline 84 is shown for the left aperture 22. The right 
aperture 24 has a similar symmetrical centerline (not shown). The 
apertures are rotated about the pitch line 86 of the link to form a 
positive tilt angle. 
The preferred aperture tilt angle of the inside link is approximately 6 
degrees, which is the angle between the symmetrical centerline and the 
pitch line of the link. This is in contrast to the guide links 16 which 
have zero aperture tilt. The pitch length of the inside links is measured 
along the pitch line, between the points of intersection 88, 90 of the 
apertures with the pitch line. The pitch points 88, 90 are the points of 
vertical tangency of the aperture inside front surface. The location of 
the pitch line in the link is determined by the link tooth form as well as 
the design of the sprocket. The pitch length of the inside link is greater 
than the pitch length of the guide link. 
The pin 20 is illustrated in FIG. 6, with the detail of the cross section 
shown in FIG. 5. The pin includes a body portion 92, which has a 
substantially flat front working surface 94 and arcuate back surface 96. 
The back surface 96 is constructed of arcs formed by a plurality of radii. 
These radii include radius 98, struck from centerpoint 100 and radii 102, 
104. 
In operation, the movement of the pin 20, of the rocker joint of the silent 
chain embodiment relative to the links of the chain, is illustrated in 
FIGS. 7, 8, and 9. FIG. 7 illustrates the pin in the straight-pull 
position of the chain. In such a position, the chain is extended between 
two sprockets and the link is being viewed in the tight strand portion of 
the chain. The rocking contact of the flat front surface of the pin occurs 
with the front arcuate portion of the aperture at contact point 110. In 
the straight-pull position of FIG. 7, the rocking contact points are the 
points of vertical tangency 88, 90, shown in FIG. 2. The rocking occurs 
along a portion of the flat surface of the pin as a rolling type action. 
This rolling action is in contrast to the sliding of a round pin within a 
round aperture of a round pin joint. A small pin-to-aperture clearance is 
provided at point 112, which is opposite the side of the rocking contact 
point 110. The minimal clearance at point 112 between the back surface 96 
of the pin and the back surface 73 of the aperture allows substantially 
free movement of the back surface of the pin relative to the link, as the 
chain articulates. In the straight-pull position, clearance between the 
pin and aperture on the back surfaces is provided in the tight strand of 
the chain. 
The pin 20 moves relative to the link to the position shown in FIG. 8, 
where the link is fully articulated. In the fully articulated position, 
the chain has wrapped around the sprocket and the link is being viewed in 
a position of being fully seated in the sprocket. Preferably, a minimum 
clearance between the back surface of the pin and the aperture surface is 
maintained in this position. 
In a timing chain drive application, the chain is provided with a 
back-bending or flexing ability. In such a motion, the pin 20 moves 
relative to the link to the position shown in FIG. 9. In this position, 
the slack side of the chain has been forced to an inward position by a 
chain snubber and the link is being viewed in the fullest position of 
backbending. 
In the preferred silent chain embodiment, the chain of the present 
invention is constructed with a block lacing. Such a block lacing is 
illustrated in FIG. 11. An example of block lacing in silent chain for an 
engine timing drive is also shown in U.S. Pat. No. 4,759,740. The inside 
links are substantially identical and placed side-by-side in the row to 
form a block. Rows or sets of such block laced inside links are preferably 
alternated with guide link rows. The sets of guide links do not contain 
any sprocket tooth contacting members. That is, they do not contain any 
links with depending teeth for sprocket tooth contact. 
In the block laced construction, the curved portion of the apertures of the 
inside links in the block act together to form a continuous curved 
surface, which is substantially continuous across the width of the chain, 
for rocking contact with the pin. The inside curved surface of the 
apertures of the block laced links therefore, effectively, forms a rocker 
for rocking action against the pin. 
The block construction also allows use of the single pin with a single type 
of inside link. Without the block lacing construction, inside links would 
be present in the guide link row. To place inside links in the guide row 
requires a second type of inside link, with the apertures reversed in 
direction, to permit lacing of the chain. Alternatively, as described 
above, the inside links may be placed in the guide row as non-flanking 
guide links. These guide links may be press fit on the pin to prevent 
rotation of the pin with respect to the link. The press fit is achieved by 
utilizing the same configuration aperture in the non-flanking guide link 
as in the flanking guide link, which matches the configuration of the pin. 
The non-flanking guide links have a pair of depending toes adapted to 
contact the teeth of a sprocket. In this embodiment, the number of links 
in the non-guide row preferably exceeds the number of links in the guide 
row. 
The use of guide links which are press fit or interference fit with the 
pins provides a link with increased fatigue strength, in comparison to a 
link which is not press fit. The use of a greater number of links in the 
non-guide row than in the guide (articulating) row reduces the contact 
stresses in the chain. 
The use of the single pin rocker joint of the present invention in the 
block lacing construction combines the benefits of the block lacing with 
the benefits of a rocker pin joint. The rocker joint is generally of 
higher efficiency than a round pin joint of comparable size and has 
generally lower wear characteristics. 
The single pin rocker joint of the present invention can be used with 
silent chain, as described, or also with a chain used for a continuously 
variable transmission (CVT). An example of a portion of such a chain is 
shown in FIG. 10. In such a chain, the power transfer occurs through load 
block members 110 that either encircle the links or are placed in a 
passageway beneath the links. The chain in FIG. 10 includes the single pin 
105 with the guide links 101 and inside links 103. The inside links in the 
guide row require apertures that are larger than the apertures in the 
flanking guide links in order to permit articulation of the links with 
respect to the pins. The inside link apertures in the guide row would also 
be in the opposite directions of the apertures of the inside link 
apertures in the non-guide row. Alternatively, the internal links in the 
guide row (non-flanking guide links) have apertures of the same shape as 
the cross-section of the pins. The internal links are preferably not block 
laced in order to provide support for the load block 110. An example of a 
power transmission chain for use in a continuously variable transmission, 
with load block members encircling the links, is shown in U.S. Pat. No. 
4,507,106. Alternatively, the power transfer can occur through the pins 
that contact the pulley sheaves. 
FIGS. 12, 13 and 14 also illustrate the rocker joint in a power 
transmission chain for a continuously variable transmission. An example of 
this type of chain is described in U.S. Pat. No. 5,007,883, which is 
incorporated herein by reference. The chain 100, or chain-belt, includes a 
plurality of interleaved or laced sets of links 102, 104. Each link has a 
pair of spaced apertures 106, 108. The apertures are arranged so that a 
pivot means in the form of a single pin can join adjacent links to permit 
the chain to articulate. On account of the lacing, different sets of links 
may have different numbers of links. 
The links are illustrated in detail in FIGS. 15 and 16. Each link 102 has a 
pair of toes 112, 114 which are downwardly disposed in a direction toward 
the shafts of the transmission. The toes are spaced apart and positioned 
to define a passageway therebetween formed by radius 115. FIG. 15 
illustrates the links located in the guide row. The guide row links 
include apertures 106, 108 that have substantially the same shape as the 
cross-sectional configuration of the pin, thereby preventing rotation of 
the link relative to the pin. The guide row links are therefore press fit 
or interference fit on the pins. The apertures have a substantially 
straight front surface 116 and a back surface 118 that is formed by a 
plurality of radii 120, 122. Blend radii 124 join the front and back 
surfaces. 
FIG. 16 illustrates the links 104 located in the non-guide row. The 
non-guide row links, or inside links, include apertures shaped to allow 
rotation of the links with respect to the pins. The apertures 126, 128 
include a convexly curved front surface 130 and a curved back surface 132. 
The back surface is formed by radius 134 and blend radii 136. The front 
surfaces are formed by radii 131, 133. The apertures have a positive tilt 
angle with respect to the horizontal. The convex front surface is only 
slightly arcuate. The front surface of the pin rocks against the arcuate 
front surface of the inside link aperture to form the rocker joint. The 
centers of curvature of the radii 131, 133 of the front surfaces are on 
opposite sides of the apertures. 
The pivot members are preferably in the form of pins, similar to the pin 
illustrated in FIG. 6. The cross-section of the pin is substantially the 
same as the aperture of the guide row links. The pin 145 is shown in FIG. 
17, and has a back surface formed by radius 140, and radii 142, 144. 
A load block 146 is associated with each set of links and is received in 
the passageway. The upper region of the load block has the same shape as 
the passageway but is only slightly smaller in size to allow the load 
blocks to be positioned in the passageway. The load blocks have a lower 
portion that extends from the passageway and has ends that are designed to 
engage the flanges of the pulleys of the continuously variable 
transmission. The load blocks are preferably formed of solid metal. 
FIGS. 12 and 14 illustrate the lacing of the guide row and non-guide row 
links in the chain. The lacing pattern includes fewer links in the guide 
rows 152 than in the non-guide rows 154. This lacing decreases the contact 
stresses in the chain. As shown in FIGS. 12 and 14, the load blocks have a 
groove or notch 148 in one end. The notch is located in the block and 
serves to position a retaining link. The retaining link and notch serve to 
restrain any movement of the links in a direction transverse to the travel 
of the chain. 
The guide rows include both external (flanking) guide links and internal 
(non-flanking) guide links. The non-guide rows include inside links. The 
guide links are press fit on the pins while the inside links rotate with 
respect to the pins, and form the single pin rocker joint. Unlike the 
silent chain joint, the CVT chain joint of FIGS. 12-14 does not allow 
substantial back-bending of the chain. 
FIG. 18 illustrates an alternate embodiment of the inside link of the chain 
of FIG. 12. The link 160 includes a large central aperture 162. The 
aperture 162 includes a pair of back surfaces 164, 166 that permit 
rotation of the pins against the back surfaces. The large central aperture 
combines the two separate apertures of the link of FIG. 15. The aperture 
includes surfaces 168, 170, 172, 174 which are constructed to retain the 
pins in position to rock against the aperture back surfaces. 
The combination of the rocker joint of the present chain with other types 
of chain and configurations of links is also possible. For example, the 
single pin rocker Joint can be used in silent chain in which the 
configurations of the links are mixed. 
While several embodiments of the invention have been described and 
illustrated, it will be understood that the invention is not limited to 
these embodiments. Those skilled in the art to which the invention 
pertains may make modifications and other embodiments employing the 
principles of this invention, particularly upon considering the foregoing 
teachings.