Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CARRIER CHAIN WITH AN IMPROVED LINK
TECHNICAL FIELD
This invention relates generally to conveying systems and, more specifically,
to a conveying system that includes carrier chains for transporting packages.
BACKGROUND OF THE INVENTION
A conveying system incorporating one or more carrier chains is commonly
used to transport cartons through a packaging machine by which the cartons are
erected, loaded, and sealed. Each carrier chain is typically tightened around
two
sprockets that are spaced apart. The links of the carrier chain engage the
teeth of
the sprockets and the sprockets rotate to drive the carrier chain. In some
applications, a guide track, having surfaces above and below the chain,
constrains
the movement of the chain to a nearly linear path as the chain moves between
the
sprockets. The amount of play between the guide track and the chain determines
how much the individual links of the chain can rotate or otherwise deviate
from the
linear path.
A typical carrier chain is a roller chain that inciudes several different
types of
links including pin links, roller links, and attachment links. The attachment
links are
spaced along each roller chain at a regular interval and a support member,
such as a
lug, is integral or attached to the attachment link.
Each support member supports and abuts a portion of a carton that has been
at least partially erected, and cooperates with other support members to
transport
the carton through a packaging machine where the carton is loaded with
articles and
folded and secured to form a package. The support members support the carton
to
keep the corners of the carton substantially square before and during loading
and as
the end flaps of the carton are closed and glued. The support members can
transport the package through the packaging machine by pushing or otherwise
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causing the package to slide along a flat supporting surface (such as a dead
plate or
otherwise any stationary support member) of the conveyor. Or the supporting
surface can be defined by conveyor plates which are attached to the carrier
chains
or otherwise are not stationary. As the package slides along the supporting
surface
of the conveyor, the frictional force between the package and the supporting
surface,between the package and the package guides and between the package
and flap folders, the force caused by any change in momentum and/or
compression
of the package result in an opposing force that is exerted against the support
members. This opposing force causes the attachment link to rotate, as is
allowed by
the guide track, and causes the support member to angularly displace relative
to a
plane that is perpendicular to the support surface or tilt according to the
degree of
rotation of the attachment link. The play between the guide track and the
rollers of
the carrier chain allow the attachment link a certain degree of rotation. A
large
amount of tilt of the support members can cause problems as or after articles
are
packaged in cartons that are transported by the carrier chains. For example,
if the
support members tilt excessively, the walls of the cartons are caused to be
slanted
such that articles are not properly packaged in the carton, articles cannot
fit through
the opening of the carton, or the walls of the carton are not squared with
respect to
the support surface as the end flaps of the carton are folded and secured to
form end
walls.
According to one solution, to compensate for forces applied to a support
member that would generate a large degree of tilt, a forward tilt is imposed
upon the
support member to compensate for the tendency of the support member to tilt
rearwardly. Thereby, the displaced or tilted position of the support member
generally
squares the corners of the package pushing against it. However, the forward
tilted
support member does not square the corners of an unloaded carton since the
unloaded carton generally does not produce as great of an opposing force
against
the support member as a package that is loaded with articles. As mentioned
earlier,
a non-square carton can lead to problems during loading. This is especially
true for
taller cartons where the upper and lower panels of the carton become more
offset
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and can require remedies such as overhead squaring to be introduced into the
process.
It is therefore desirable to limit the degree of differential tilt of the
support
members regardless of the magnitude of the opposing force exerted by either an
unloaded carton or loaded package. This has been attempted using several
methods. One method for decreasing differential tilt is to tightly control the
distance,
or play, between the surfaces of the chain guide track and the rollers of the
carrier
chain. This is expensive from a manufacturing standpoint since a guide track
with
tighter tolerances requires more precision to manufacture. Additionally,
tighter
tolerances cause increased contact and friction between the carrier chain and
the
guide track. As a consequence, the sprockets must supply a greater drive
force,
which in turn, causes the chain links and guide track to wear out faster.
Another
method is to increase the pitch of each individuai attachment link. However,
the
pitch of the attachment link is dependent on the characteristics (diameter,
spacing
is between teeth, and the like) of the sprocket that is selected to drive the
other links of
the carrier chain. Thus, the pitch of the attachmenfi link can only exceed a
standard
chain link pitch by a limited amount if it is to be used with a sprocket that
is designed
for use with the standard chain link pitch.
Therefore, a heretofore unaddressed need exists in the industry to address
the aforementioned deficiencies and inadequacies. What is needed is an
improved
carrier chain that reduces the undesirable differential tilt of an attached or
integral
support member in response to a force is applied to the support member.
Further,
the carrier chain should be easily manufactured and should have the ability to
be
incorporated into a standard roller chain.
SUMMARY OF THE INVENTION
The various embodiments of the present invention overcome the
shortcomings of the prior art by providing a carrier chain that includes an
improved
attachment link with a wing that reduces the tilt of an attached support
member, such
as a lug, which is used for supporting and transporting cartons or packages in
a
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packaging machine. This attachment link is one of a series of rotatably
connected
links included in a carrier chain and is spaced intermittently throughout the
carrier
chain, according to application-specific considerations such as the carton
widths that
must be accommodated. The attachment link may include a vertically extending
arm
s to which a support member can be attached or the support member can be
integral
to the attachment link.
According to the various embodiments, the carrier chain travels within a guide
track system. The attachment link includes a wing that contacts at least.one
of the
adjacent chain links that form the carrier chain, in reaction to a force that
is applied to
a support member. By contacting at least one of the chain links, the wing
limits the
rotation of the attachment link, and thereby restricts the rotational
displacement of
the support member that is attached or integral to the attachment link.
Specifically,
the wing causes the attachment link and the adjacent link to become
interlocked (i.e.,
fixed in relation to one another) so as to share an axis of rotation without
is substantially rotating relative to one another and to increase the
effective pitch of the
combination. The increased pitch of the combination restricts the rotation of
the
attachment link and the adjacent chain link about the shared axis of rotation
within
the confines of the guide track.
In certain exemplary embodiments, the attachment link functions as a pin link
and is thereby interconnected with roller links. The wing which extends from
the
attachment link can contact a pin link that is interconnected to the
attachment link by
a roller link or can contact the roller link itself to restrict the rotation
of the attachment
link and the roller link relative to one another about a shared axis of
rotation.
In alternative embodiments, the attachment link functions as a roller link,
and
is thereby interconnected with pin links. The wing, which extends from the
attachment link, can contact a roller link that is interconnected to the
attachment link
by a pin link or can contact the pin link itself to restrict the rotation of
the attachment
link and the pin link relative to one another about a shared axis of rotation.
The attachment link includes a first plate having a base portion from which
the
wing extends. Specifically, the wing extends in a direction that is opposite
the
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direction of travel of the carrier chain. A lower edge of the wing extends
above an
upper edge of the plate of the chain link that is contacted by the wing. The
lower
edge of the wing contacts the upper edge of a plate of a chain link so as to
restrict
the rotation of the adjacent chain link. In the exemplary embodiment, the
attachment
link functions as a pin link and the chain link that is contacted by the wing
is another
pin link. The adjacent chain link is a roller link that shares an axis of
rotation with
and is interconnected with the attachment link and the contacted pin link. In
alternative embodiments, the wing can be arranged to contact the adjacent
roller link
or other features of the links, including the pins.
The exemplary base portion of the attachment link plate is generally
rectangular with rounded ends, while the pin link plates and roller link
plates may
have a generally hourglass contour. However, the base portion of the
attachment
link, the pin link plates, and the roller link plates can each be constructed
in any
suitable shape. Those skilled in the art will appreciate that the maximum
pitch of the
attachment link is dictated at least in part by the sprocket.
The attachment link plate can include a second wing that is substantially
similar to the first wing and extends outward from the base portion in the
direction of
travel of the carrier chain. Having both wings enables the chain to run in
either
direction and allows the winged plate of the attachment link to be positioned
on
either side of the chain. Also, the exemplary attachment link plate includes
an arm
or other means for attaching a support member that extends from the upper edge
of
the base portion such that the support member is attached directly to one of
the
attachment link plates. Alternatively, the support member can be integral to
the
attachment link plate and extend from the upper edge of the base portion.
When the attachment link experiences a force that generates rotational
motion, the lower edge of the wing makes contact with the upper edge of a pin
link.
This engagement restricts the rotation of the roller link that connects the
attachment
link and contacted pin link relative to the attachment link, such that the
roller link
tends to align and rotate with the attachment link. Since the attachment
link"and
roller link rotate as one, the pitch of the combination is extended, and the
rollers at
the ends of the arrangement of contacting links react with surfaces of the
guide
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track. In other words, these "reaction rollers" contact the surfaces of the
guide track
to prevent the attachment link and roller link from rotating further.
The wing effectively reversibly increases the pitch between rollers that
contact
the surfaces of the guide track, without increasing the pitch of the
attachment link, as
the attachment link encounters the rotational force. Increasing the pitch
between
reaction rollers reduces the amount of resultant tilt of the attachment link
in the guide
track.
The foregoing has broadly outlined some of the aspects and features of the
present invention, which should be construed to be merely illustrative of
various
potential applications of the invention. Other beneficial results can be
obtained by
applying the disclosed information in a different manner or by combining
various
aspects of the disclosed embodiments. Accordingly, other aspects and a more
comprehensive understanding of the invention may be obtained by referring to
the
detailed description of the exemplary embodiments taken in conjunction with
the
accompanying drawings, in addition to the scope of the invention defined by
the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. I is a partial perspective view of a conveying system that includes
exemplary carrier chains for transporting a package, according to the present
invention.
FIG. 2 is a partially-exploded perspective view of a portion of one of the
carrier chains of FIG. 1.
FIG. 3 is a partial side elevation of a portion of one of the carrier chains
of
FIG. 1, showing the relationship of the carrier chain with a guide track.
FIG. 4 is an end elevation taken along the line IV-IV in FIG. 3, showing the
relationship of the carrier chain to the guide track.
FIG. 5 is a partial side elevation of a portion of one of the carrier chains
of
FIG. 1, showing the function of a wing of an attachment link.
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DETAILED DESCRIPTION
As required, detailed embodiments of the present invention are disclosed
herein. It must be understood that the disclosed embodiments are merely
exemplary
of the invention that may be embodied in various and alternative forms, and
combinations thereof. As used herein, the word "exemplary" is used expansively
to
refer to embodiments that serve as illustrations, specimens, models, or
patterns.
The figures are not necessarily to scale and some features may be exaggerated
or
minimized to show details of particular components. In other instances, well-
known
components, systems, materials, or methods have not been described in detail
in
order to avoid obscuring the present invention. Therefore, specific structural
and
functional details disclosed herein are not to be interpreted as limiting, but
merely as
a basis for the claims and as a representative basis for teaching one skilled
in the art
to variously employ the present invention.
Referring now to the drawings in which like numerals indicate like elements
throughout the several views, the drawings illustrate certain of the various
aspects of
a carrier chain with exemplary embodiment of the improved attachment link. The
attachment link has a wing which functions to limit the tilt of a support
member, such
as a lug, which is attached or integral to the attachment link. The carrier
chain
attachment link is illustrated in the context of an exemplary packaging
machine
which transports cartons or packages. However, it should be understood that
the
scope of the invention is not limited to packaging machines or to applications
involving the transportation of articles. Rather, the invention is applicable
to any
application where it is desirable to limit or control the tilt of a support
member of a
carrier chain as a force is applied to the support member.
Referring to FIG. 1, an exemplary conveying system includes a set of carrier
chains 12a, 12a', 12b, 12b' that run in parallel and that transport a package
50
(shown in phantom lines) through a packaging machine. The carrier chains and
their
elements are substantially similar such that suffixes "a", "a"', "b", and "b"'
are used to
distinguish the carrier chains from one another. The carrier chains with
references
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that include a suffix "a" substantially mirror the carrier chains with
references that
include a suffix "b". Further, the innermost carrier chains and their
corresponding
elements are also referenced by a prime symbol. For example, the outer carrier
chain on one side is labeled 12a and the adjacent inner carrier chain on that
side is
labeled 12a. For simplicity, a description of the elements of one carrier
chain will be
provided since the description of the carrier chain is generally applicable to
the other
carrier chains. In addition, a description of the relationship between carrier
chains
that include a suffix "a" is generally applicable to carrier chains that
include a suffix
"b" since the sets of chains substantially mirror one another.
To establish a frame of reference, without limitation, the working section of
each carrier chain will be described as traveling along a hypothetical linear
course in
the horizontal plane, although other orientations and configurations are
contemplated, and any part of or the entire path of the carrier chains may
include
curves, bends, and other diversions as the application dictates. In one
embodiment,
the working section of each carrier chain may be routed above conveying
articles so
that the support members extend downwardly from the working section to engage
the articles. Furthermore, all of the carrier chains are described as
traveling along
parallel paths that together define the drive train for conveying articles on
a single
conveying surface, as is described in more detail below. Thus, the term
"outward"
indicates proceeding or directed away from the center of the conveying
surface, and
"inward" indicates proceeding or directed toward the center of the conveying
surface.
The carrier chains 12a, 12a' carry mounted or integral support members that
support and transport articles. In the exemplary embodiment, the support
members
are lugs 28a, 28a' that are dimensioned and positioned for supporting and
transporting a carton C. The carrier chains 12a, 12a' are adjacent to one
another
and run in parallel and the lugs 28a, 28a' extend from respective carrier
chains 12a,
12a' so as to be aligned as they move in the direction of travel. Each lug is
mounted
or integrally attached along its inward facing edge, and has an end edge that
is
suspended above the horizontal plane in which the carrier chain travels. In
the
exemplary embodiment, the suspended portions of the lugs 28a extend outwardly
from the inside edge of the outer carrier chain 12a and the suspended portions
of the
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lugs 28a' extend outwardly from the outside edge of the inner carrier chain
12a' such
that each of the lugs 28a, 28a' is disposed and aligned above the outer
carrier chain
12a. Further, the lugs 28a'that extend from the inner chain 12a' are greater
in width
than the lugs 28a that extend from the outer chain 12a such that the outward
facing
outer surfaces Xa, Xa' of the lugs 28a, 28a' are substantially coplanar. This
arrangement is of utility in carton-loading process wherein the lugs 28a, 28a'
are
used to guide the folding of the opposed side end flaps of cartons C. In
alternative
embodiments, the lugs can be alternatively dimensioned or positioned to
support and
transport a carton with other dimensions or other articles. Thereby, the
dimension
and position of the support members that extend from each of the carrier
chains is a
design decision that is dependent on the application.
In the exemplary embodiment, each lug 28a is a tapered block formed of
plastic, although its shape, size, and constituent material are design choices
dictated
by the application. Those who are skilled in the art will understand that each
lug 28a
can be formed from a variety of materials into a variety of sizes and shapes
in order
to provide the necessary spacing and support when conveying a carton C, as
shown
in FIG. 1.
The lugs 28a, 28a' are aligned in an alternating series with a carton C
disposed therebetween such that a lug 28a which extends from the carrier chain
12a
supports the leading end of the carton C (shown in phantom lines) and a lug
28a'
which extend from the carrier chain 12a' supports the trailing end of the
carton C.
The carrier chains 12a, 12a' are separately driven such that the chains 12a,
12a' can
be phased or adjusted relative to one another to vary the distance between
lugs
28a, 28a', for example, to accommodate packages of different sizes. Carrier
chains
12b, 12b' are similarly driven by separate drive means.
Referring to FIG. 2, one of the carrier chains 12a is now further described.
The carrier chain 12a is a roller chain, which is generally known in the art,
which
comprises a repeating series of attachment links 10, pin links 14, and roller
links 16.
A typical carrier chain includes an alternating series of rotatably connected
pin links
14 and roller links 16. Referring to FIG. 2, each pin link 14 is connected
between
two roller links 16 as the pins 21 of the pin link 14 are received in the
bushings 19 of
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the adjacent roller links 16. As a pin is received in a bushing, the central
axis of the
pin and the central axis of the bushing are substantially aligned such that
the central
axes define an axis of rotation about which the pin link and the roller link
can rotate
relative to one another. According to certain embodiments of the present
invention,
s the attachment links 10 function as pin links 14 in that they rotatably
connected with
roller links 16. Thus, the attachment links 10 can be substituted for certain
pin links
14 in the carrier chain 12a such that the attachment links 10 and the adjacent
roller
links 16 can rotate relative to one another, according to the desired spacing
or pitch
between lugs for each carrier chain, as will be described in greater detail
below.
Those skilled in the art will understand that an attachment link 10 may be
used as
part of many types of chain including, but not limited to, a standard power
transmission roller chain, and that the attachment link 10 may alternatively
function
as a roller link disposed between pin links 14.
The attachment link 10 and the pin link 14 each include two plates that are
is secured together. More specifically, each attachment link 10 includes a
first
attachment link plate 22 and a second attachment link plate 24 that are
secured to
one another at or near the ends of a pair of pins 18. -The attachment link
plates 22,
24 can be fashioned using any system, method, and material for making a link
plate
having the properties and components described herein including, but not
limited to,
laser cutting, punching, or machining from heat-treated steel.
In the exemplary embodiment, the pins 18 extend at least partially through
apertures in the attachment link plates 22, 24 and are riveted or knurled such
that
the ends of the pins 18 cannot slide out of the apertures in the attachment
link plates
22, 24. It should be understood that, in alternative embodiments, any method
of or
means for securing the ends of the pins 18 to the attachment link plates 22,
24 may
be used including, but not limited to, T-pins, cotter pin joints, spring
clips, or pressure
fitting. Similarly, each pin link 14 includes two pin link plates 15 that are
secured at
or near the ends of pins 21. The ends of the pins 21 can be secured to the pin
link
plates 15 using any method of securing as described for the attachment link
10.
Roller links 16 each include two roller link plates 17 that are secured at or
near the ends of bushings 19. The bushings 19 can be press fit into holes in
the
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roller link plates 17 to secure the roller link plates 17 to the ends of the
bushings 19.
In alternative embodiments, the ends of the bushings 19 can be secured to the
roller
link plates 17 using any method of securing as described for the attachment
link 10.
Rollers 20 are disposed on the bushings 19 to facilitate engagement of the
carrier
chain 12a with associated sprockets (not shown). The rollers 20 can rotate on
a
respective bushing 19 to facilitate movement of the carrier chain 12a around
the
sprockets and through the guide track.
In the exemplary embodiments shown, a pitch P1 of attachment link 10 is
approximately double a pitch P2 of the links 14, 16. The pitch P1 is defined
as the
distance between the central axes of the pins 18. The pitch P2 is defined as
the
distance between the central axes of the pins 21 for pin links 14 and as the
distance
between the central axes of the coaxial bushings 19 and rollers 20 for the
roller links
16. Preferably, but not necessarily, the pitch P2 of each link 14, 16 conforms
to
American National Standards Institute (ANSI) standards and corresponds to the
size
of the sprocket used in the particular application. The pitch P1 can be
greater than
the pitch P2 by a limited amount and still work with a sprocket that is
designed for a
pitch P1. As described in further detail below, increasing the pitch P1 of the
attachment link 10 functions to reduce the maximum angle of rotation of the
attachment link 10. However, it should be noted that, in certain embodiments,
the
pitch P1 is no greater than and could conceivably be less than the pitch P2.
The
various embodiments include a wing on the attachment link 10 that functions to
reduce the maximum angle of rotation of the attachment link 10 and thereby to
reduce the tilt of the lug 28a.
In the exemplary embodiments, the first attachment link plate 22 includes
means for attaching a support member, such as the lug 28a. The exemplary means
for attaching is a bracket arm 26 that is an integral extension of the first
attachment
link plate 22. The bracket arm 26 is located intermeditely, if not centered,
between
the pins 18 of the respective attachment link 10 and extends upwardly from a
base
portion B of the first attachment link plate 22 in a direction that is
generally
perpendicular to an imaginary line L, which extends between the pins 18 of the
attachment link 10. In alternative embodiments, the bracket arm 26 may be
angled
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with respect to the imaginary line L to accommodate an irregularly shaped
carton or
to compensate for an acceptable degree of differential tilt.
To facilitate attaching the detachable lug 28a to the attachment link 10, in
the
exemplary embodiment, the bracket arm 26 includes a slot aperture 30 that is
at
least slightly elongated and a relatively close fitting round aperture 32 that
extend
through the arm 26. The slot aperture 30 allows compensation for slight
deviations
in manufacturing tolerances. The lug 28a is fastened to the bracket arm 26
with
fastening means such as bolts, pins, or screws that are passed through
apertures
30, 32 and inserted or threaded into holes 34. As mentioned above, the bracket
arm
io 26 may be angled to tilt the lug 28a somewhat. Alternatively, or in
addition, the holes
34 may be skewed to position the lug 28a to have a forward tilt relative to
the bracket
arm 26. In applications that require a titled lug, the angle of forward tilt
is determined
such that, when the lug 28a engages a loaded carton or is otherwise subjected
to a
rotational force, the angle of rotation of the attachment link 10 or of the
bracket arm
26 offsets the forward tilt and the lug 28a is substantially normal to a
supporting
surface on which the carton C is disposed. It is contemplated as well that
some
applications may tolerate a small degree of backward tilt of a loaded lug, in
that the
forward tilt only partially compensates for the backward rotation encouraged
by the
working forces. It should be noted that any means for attaching the lug 28a
onto the
bracket arm 26 can be used including, but not limited to, chemical bonding,
adhesives, mechanical fasteners, welding, riveting, or pinning. In an
alternative
embodiment, the lug 28a may be a preformed integral extension of the
attachment
link plate 22. In another alternative embodiment, the lug 28 may be composed
of
two separate parts, i.e., a base part secured to the attachmenfi link 10 and a
quick
change extension part detachably engaged with the base part by means, for
example, of a key-and-groove connection.
With reference to FIGs. 1-3, the first attachment link plate 22 includes wings
36 that extend from opposite ends of a base portion B of the first attachment
link
plate 22. Referring to FIG. 3, each wing 36 is dimensioned and positioned such
that,
with the attachment link 10 is incorporated in the carrier chain 12a, the
lower edge
El of the wing 36 is disposed adjacent to or above a portion an upper edge E2
of a
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pin link plate 15 of the adjacent pin link 16. Additionally, the contour of
the lower El
edge of each wing 36 closely conforms to the contour of the portion of the
upper
edge E2 of the pin link plate 15 of the adjacent pin link 16. In the exemplary
embodiment, the wings 36 are contoured to closely complement the contour of
the
adjacent pin link plate 15. In alternative embodiments, each wing 36 may have
any
shape, such as the shape of a curved ledge or a cantilever beam, so long as it
maintains the functionality described herein. In addition, the shape of the
wings 36
may be altered to conform to pin link plates 15 of different sizes and shapes.
As
described in further detail below, the contour of the lower edge El of each
wing 36 is
selected to engage an upper edge E2 of the pin link plate 15 of the adjacent
pin link
16 to limit the angle of rotation of the attachment link 10 and a lug 28a
attached
thereto.
It should be understood that the wings 36 are included at or near each of the
opposite ends of the base portion B as an option so that the carrier chain 12a
is
directionally reversible. However, in certain embodiments, only the trailing
or
upstream end of the base portion B includes a wing 36. It should also be
understood
that the second attachment link plate 24 of the attachment link 10 can include
at
least one wing 36 and that either of the attachment link plates 22, 24 can
include one
or both of the wing and bracket arm features. Further, in the exemplary
embodiment, the wings 36 and the bracket arm 26 are integral to the first
attachment
link plate 22. In alternative embodiments, the wings 36 and/or the arm 26 may
be
attached to the base portion B of the first attachment link piate 22 by any
method
including, but not limited to, welding or bolting.
Referring to FIGs. 3-5, a chain guide 60 includes a guide track 38 that
constrains the movement of the carrier chain 12a as it travels between
sprockets
(not shown) or otherwise prevents the carrier chain 12a from leaving the
substantially linear or otherwise intended path defined by the guide track 38.
The
guide track 38 is substantiaily parallel to a direction of travel N of the
carrier chain
12a and includes an upper section 40 with an upper surface 41 and a lower
section
42 with a lower surface 43. As best shown in FIG. 4, the links 10, 14, 16
straddle the
upper section 40 and the lower section 42, with the upper surface 41 and the
lower
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surface 43 being adjacent to, but not necessarily in contact with, upper and
lower
surfaces of the rollers 20, respectively. The upper section 40 and the lower
section
42 are disposed between the inside surfaces of roller link plates 17 to
restrict the
lateral movement of the carrier chain 12a or otherwise keep the carrier chain
12a in
the guide track 38. The distance between the upper and lower surfaces 41, 43
is
determined so as to restrict the vertical displacement and angle or rotation
of the
links 10, 14, 16 without making the tolerances too tight so as to undesirably
increase
friction and wear on the guide track 38 and associated carrier chain 12a
components. Accordingly, the maximum height HI of each roller link plate 17 is
io greater than the height H2 of the guide track 38 and the diameter D of the
roller 20 is
less than the height H2 of the guide track 38.
The function of the wings 36 of the attachment link 10 will now be described.
For the purpose of clarity, certain elements of the carrier chain 12 including
outside
links 14, inside links 16, rollers 20, and wings 36 will be accented with a
prime
symbol to denote a specific element in the carrier chain in relation to the
attachment
link 10. Like elements, starting from the attachment link 10 and moving in the
direction opposite the line of travel N, will be given an increasing odd
number of
prime accents. Like elements, starting from the attachment link 10 and moving
in the
direction of travel N, are given an increasing even number of prime accents.
Additionally, for clarity, the rollers 20 that are in contact with the
surfaces 41, 43 of
the guide track 38 will be referred to as reaction rollers.
A force F is exerted against lug 28 as the lug 28 transports the carton C over
a surface S and otherwise supports the carton C. The force F causes the
attachment link 10 to rotate in a counterclockwise direction as shown from the
perspective of FIGs. 3 and 5. Let it be noted that force F is also generated
on an
unloaded lug 28a simply by virtue of the acceleration of the carrier chain 12a
and
the length and mass of the lug 28a.
Referring to FIG. 5, as the attachment link 10 begins to rotate, and indeed
rotates beyond a prescribed or predefined acceptable degree of rotation, the
lower
edge El of wing 36' abuts or otherwise contacts the upper edge E2 of the one
of the
links in the carrier chain 12a. This contact link K can be the adjacent link J
to which
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the attachment link 10 is directly connected (as shown in FIGs. 6 and 7), or
the
contact link K can be another of the series of links that form the chain link
12a (as
shown in FIGs. 1-5). In the first embodiment, and as best shown in FIG. 5, the
attachment link 10 contacts a pin link plate 15' of the pin link 14'. This
contact resists
the tendency of the end of the adjacent link J (roller link 16', which is
connected to
the pin link 14') to rotate further relative to the attachment link 10, in a
clockwise
direction from the perspective of FIGs. 3 and 5, about an axis of rotation
that is
defined by the central axis of the pin 18'. Thereby, as the attachment link 10
is
further rotated in a counterclockwise direction, the roller link 16' is
constrained to be
io substantially in line with the attachment link 10 as it tilts. For example,
in certain
embodiments, the pins 18', 18", 21'are aligned as the attachment link 10 and
the
constrained roller link 16' contact one another, and potentially, rotate
together.
The roller 20"' becomes the reaction roller, as it is disposed against the
lower
surface 43 and the attachment link 10 and the roller link 16' are rotated as
one in a
is counterclockwise direction about an axis of rotation that is defined by the
central axis
of the pin 21'. Similarly, the roller 20" becomes the reaction roller against
the upper
surface 41. Referring to FIG. 5, as the reaction rollers 20", 20"' are in
contact with
the upper and lower surfaces 41, 43, respectively, the roller 20' is offset
from or
otherwise not in contact with either of the surfaces 41, 43. A line Y that is
defined
20 between the pins 18", 21' is at an angle with respect to the horizontal
plane or
otherwise with respect to a line Z that is parallel to or defined by the upper
or lower
surface 41, 43. The line Z can be defined by the pins 18", 21' as the rollers
20", 20'#F
are both in contact with the lower surface 43. Thus, the angle between the
line Z
and the line Y represents a maximum permissible angle of rotation A, which may
be
25 infinitesimal and is preferably acute.
Referring to FIG. 5, an imaginary right triangle can be formed by a vertical
line
V which extends from the upper end of the line Y to intersect the line Z.
Thereby, the
line Y is the hypotenuse and the lines V, Z are perpendicular to one another.
The
vertical line V is equal to a vertical distance between the reaction rollers
20", 20"' as
30 they are in contact with the upper and lower surfaces 41, 43, respectively.
Further,
the length of the line Y which defines the hypotenuse is equal to the pitch P3
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between the reaction rollers 20", 20"'. The pitch P3 is substantially equal to
the
pitch P1 of the attachment link 10 plus the pitch P2 of the adjacent link J
(roller link
16').
In contrast, it should be understood that, if the wing 36' was not present,
the
attachment link 10 would rotate until the rollers 20', 20" came into contact
with the
lower and upper surfaces 43, 41, respectively. The vertical distance between
the
rollers 20', 20" would be the same but the length of the hypotenuse of the
resulting
right triangle would have a length substantially equal to the pitch P2 which
is defined
between the pins 18', 18".
It should be understood that increasing the length of the hypotenuse
decreases the angle of rotation A if the vertical line V remains constant.
Accordingly,
the angle of rotation A is less if the length of the hypotenuse is equal to
the length of
the pitch P3 rather than the length of the pitch P2.
For illustrational purposes, the amount of tilt of the attachment link 10 and
the
clearance between the rollers 20 and the upper and lower sections 40, 42 are
exaggerated in FIGs. 3 and 5.
The principles of the invention are capable of application in innumerable
alternative embodiments and permutations of embodiments. In each of these
embodiments shown in FIGs. 6 and 7, for example, the chain link that is
contacted
(i.e., the contact link K) is a roller link (16), which may or may not be the
adjacent link
J to which the attachment link 10 is directly connected. In the embodiment
shown in
FIG. 6, the wing 36 is enlarged in thickness and extends over the adjacent
link JIK
(here, a roller link 16) so as to contact an upper edge of one of its end
plates in
response to a force applied to the support member (not shown). Thus, the
roller link
16 is both the contact link K and the adjacent link J to which the attachment
link 10 is
directly connected. In the embodiment shown in FIG. 7, the wing 36 is
rotatably
connected directly to a pin link 14, so the attachment link 10 functions as a
roller link,
and the end plate 15 of the pin link 14 is disposed on the outside of the
attachment
link plate 22. The bottom edge El of the wing 36 is disposed above the upper
edge
E2 of the contact link K (here, roller link 16) so as to contact an upper edge
of one of
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its end plates in response to a force applied to the support member (not
shown). It is
further contemplated that the attachment plate 10 may contact both the
adjacent link
J and at least one other chain link that is connected to the adjacent link,
and thus
there may be multiple contact links K for any one wing 36. It is aiso
contemplated
that the support member can be connected to the plate 24 rather than the plate
22
bearing the wing 36.
It must be emphasized that the above-described embodiments are merely
exemplary illustrations of implementations set forth for a clear understanding
of the
principles of the invention. Many variations and modifications may be made to
the
io above-described embodiments without departing from the scope of the claims.
All
such modifications, combinations, and variation are included herein by the
scope of
this disclosure and the following claims.
