Overhead pusher lug assembly for packaging machines

An overhead pusher lug assembly for stabilizing the top portions of cartons in a carton packaging machine comprises an endless chain conveyor having an array of pusher lugs rotatably mounted thereto at spaced intervals. The lugs are rotatable between a first position wherein the lugs extend upwardly from the lower flight of the conveyor and a second position wherein the lugs extend downwardly from the lower flight of the conveyor for insertion between adjacent cartons on a carton conveyor. As the pusher lugs move onto the lower flight of the conveyor, they engage the end of an elongated bar, which rotates or flips the pusher lugs into place between underlying cartons so that the lugs do not impact and disfigure trailing cartons on the carton path.

TECHNICAL FIELD 
This invention relates generally to article packaging machines of the type 
used to package beer and soft drink containers into six, twelve, and 
twenty-four pack cartons. More particularly, the invention relates to an 
overhead pusher lug mechanism that functions in conjunction with the 
carton conveyor to stabilize cartons as they are conveyed progressively 
through the packaging machine. 
BACKGROUND OF THE INVENTION 
Article packaging machines are commonly used to package articles such as 
soft drinks and beer into cartons for storage and display. An example of 
such a packaging machine is shown in U.S. patent application Ser. No. 
08/118,111. In general, most article packaging machines include a conveyor 
for moving cartons along a path in spaced sequential relationship. As the 
cartons are conveyed along the path, adjacent sections of the machine 
function to insert articles such as beverage cans into the cartons 
whereupon the cartons are progressively sealed and moved out of the 
machine for collection and transport. 
Most carton conveyors in packaging machines include a conveyor bed having 
spaced arrays of upstanding lugs that function to space the cartons on the 
conveyor bed and push them along the path in their spaced sequential 
relationship for packaging. In some packaging machines, such as that 
disclosed in the referenced patent application, the spacing between the 
conveyor lugs is variable to accommodate cartons of different widths. For 
example, in beverage container packaging machines, cartons are commonly 
either 51/4 inches wide or 111/4 inches wide depending upon the number of 
articles packaged in the carton. Thus, conveyor lugs on these machines 
generally are adjustable to provide either 6 inch or 12 inch spacing 
between lugs to accommodate cartons of either width. 
A common problem with article packaging machines, and with beverage 
container packaging machines in particular, is that the top portions of 
empty open cartons being conveyed along the path tend to drag or lag 
behind the bottom portions that are held in place and pushed by the 
conveyor lugs. This causes the cartons to become deformed as they move 
along the path. As a result, articles cannot be inserted easily into the 
cartons and, in fact, can impact the skewed cartons causing a machine 
jamb. To address this problem, many packaging machines employ an overhead 
pusher lug assembly to support and brace the top portions of cartons as 
they move along the path. While such overhead pusher lug assemblies vary 
in detailed operation, in general they comprise an endless flexible 
conveyor such as a chain having a lower flight that is positioned above 
the tops of the cartons and moves along in synchronization therewith. An 
array of downwardly projecting lugs are fixed to the chain and extend into 
the spaces between cartons to engage and support the top portions of 
cartons as they move along the path. As a result, the cartons are 
maintained in their square undeformed orientations for easy insertion of 
articles. 
In the past, overhead pusher lug assemblies have exhibited numerous 
problems and shortcomings. For example, it is desirable that the lugs of 
the assembly extend as far as possible into the space between the cartons 
to provide maximum area of engagement for supporting the cartons. 
Unfortunately, the length of the lugs is naturally limited by the close 
spacing of the cartons on the conveyor. For example, as each lug moves 
around its drive sprocket at the upstream end of the carton conveyor and 
onto the lower flight of its conveyor, it also moves into the position 
between two adjacent cartons. If the lug is too long or if the carton 
spacing is a bit less than expected, the lug will impact the top corner of 
the trailing carton as it rounds the sprocket thereby deforming the 
carton. As a result, the entire packaging machine must be shut down and 
the deformed carton replaced before the packaging operation can be 
resumed. 
Another problem with prior art overhead pusher lug mechanisms is that they 
have not been easily adaptable to cartons of different widths. Usually, 
when setting up the machine for a different width carton, lugs on the 
overhead pusher lug assembly have to be manually removed and refixed to 
their conveyor chain at the desired spaced intervals. Obviously, such a 
procedure is time consuming and requires the knowledge and resources of 
valuable trained personnel. Such manual adjustment of the overhead pusher 
lug spacing is particularly troublesome on modern beverage packaging 
machines where the lugs on the carton conveyor itself typically are easily 
and quickly adjustable. 
Accordingly, there exists a continuing and heretofore unaddressed need for 
an efficient effective overhead pusher lug assembly for packaging machines 
wherein the size of the individual lugs is not unreasonably limited by the 
danger of the lugs impacting and deforming cartons as they move around 
their sprockets and between the cartons on the carton conveyor. A further 
need exists for an overhead pusher lug assembly that is quickly and easily 
adjustable to accommodate cartons of different widths on the carton 
conveyor. It is to the provision of such an overhead pusher lug assembly 
that the present invention is primarily directed. 
SUMMARY OF THE INVENTION 
Briefly described, the present invention, in a preferred embodiment 
thereof, comprises an overhead pusher lug assembly for supporting the top 
portions of open empty cartons in an article packaging machine as the 
cartons are moved in spaced sequential fashion along a carton conveyor. 
The assembly comprises an endless flexible chain conveyor having an upper 
flight and a lower flight. The lower flight of the chain conveyor is 
positioned to overlie cartons on the path and is oriented substantially 
parallel to the direction of carton movement along the path. The conveyor 
chain extends around and is driven by a pair of spaced sprockets with one 
sprocket being positioned at the upstream end of the carton conveyor and 
the other sprocket being positioned at the downstream end of the carton 
conveyor. The conveyor chain is driven to move its lower flight in the 
direction of and in synchronization with the carton conveyor. 
An array of generally triangular pusher lugs are rotatably mounted at 
spaced intervals along the chain conveyor. Each of the pusher lugs is 
rotatable on the conveyor between a first position wherein the lug 
projects generally upwardly from the lower flight of the conveyor in a 
direction away from the carton path and a second position wherein the lug 
projects generally downwardly from the lower flight of the conveyor in a 
direction toward the carton path. The pusher lugs are sized such that, 
when they are in their second positions on the lower flight of the 
conveyor, they project into the spaces between cartons on the path and 
bear against the upper top portion of leading cartons to support, 
stabilize, and help push the cartons along the path. 
In the preferred embodiment, the pusher lugs on the chain conveyor are 
arranged in a first longitudinally aligned array and a second 
longitudinally aligned array that is laterally displaced from the first 
array. A first retaining bar extends generally along and just above the 
lower flight of the conveyor and is aligned with the lugs of the first 
array. Similarly, a second retainer bar extends along the lower flight of 
the conveyor beside the first bar and is aligned with the second array of 
pusher lugs. One or both of the retaining bars is retractable out of the 
path of the lugs for purposes described in more detail below. 
Each of the retainer bars has a contoured end portion located beside the 
sprocket at the upstream end of the pusher lug assembly. The end portions 
of each retainer bar are positioned to engage the pusher lugs in the array 
with which the bar is aligned as the lugs move around the upstream 
sprocket and onto the lower flight of the conveyor. This causes the lugs 
to rotate or flip from their first lock positions to their second 
positions as they move onto the lower flight of the conveyor chain. The 
conveyor chain is synchronized with the movement of cartons along the 
carton path so that the rotation of the pusher lugs causes each lug to be 
flipped into position between two adjacent cartons on the path just as the 
lug rounds the sprocket and moves onto the lower flight of the conveyor 
chain. Since the lugs are flipped into position at the proper time rather 
than simply moving around the sprocket into position, the possibility that 
a lug will impact and deform one of the cartons on the path is virtually 
eliminated. As the rotated pusher lugs move along the lower flight of the 
conveyor supporting cartons below, their top edges ride along and against 
the bottom edge of their retainer bar, which holds them down and prevents 
them from being flipped back up while they help push the cartons along the 
carton path. 
If both retainer bars are in their operable positions, then each lug in 
both of the lug arrays along the conveyor chain is engaged by its 
respective bar and is flipped or rotated into the space between adjacent 
cartons. Therefore, cartons having a width corresponding to the distance 
between adjacent lugs on the conveyor chain are accommodated by this 
arrangement. However, when one of the retainer bars is raised into its 
inoperable position, the other pusher bar engages and rotates only the 
lugs of its lug array; i.e., only every other pusher lug on the conveyor 
chain. The lugs of the other array are not rotated and stay in their first 
locked positions extending upwardly in inoperable orientations away from 
cartons on the carton path. Thus, cartons having a width corresponding to 
the distance between every other lug are accommodated by this arrangement. 
Accordingly, the pusher lug assembly of this invention is quickly and 
easily adjustable to accommodate cartons having different widths simply by 
raising or lowering one of the retainer bars that flip the lugs into 
position between cartons. 
As the pusher lugs move off of the lower flight of the conveyor chain, they 
travel up and around the downstream sprocket and onto the upper flight of 
the conveyor chain. Here, they encounter and engage a cam block that flips 
or rotates them back to their first locked positions before they again 
move around the upstream sprocket and onto the lower flight of the 
conveyor. Thus, the process is repeated over and over with the pusher lugs 
functioning to support and help push along the top portions of cartons 
being conveyed along a carton path. 
Thus, an overhead pusher lug assembly is now provided wherein the pusher 
lugs are flipped into position between adjacent cartons on the carton path 
so that they do not impact and deform cartons on the path. In addition, 
the pusher lug assembly of this invention is easily adaptable to 
accommodate cartons of different widths simply by raising or lowering the 
appropriate retainer bar as needed. These and other objects, features, and 
advantages of the invention will become more apparent upon review of the 
detail description provided below when taken in conjunction with the 
accompanying drawings, a brief description of which follows.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now in more detail to the drawings, in which like numerals refer 
to like parts throughout the several views, FIGS. 1-3 illustrate an 
overhead pusher lug assembly that embodies principals of the present 
invention in a preferred form. In these figures, the size of the pusher 
lug mechanism has been exaggerated relative to the size of the cartons and 
the carton conveyor in order to depict clearly the functional details of 
the invention. In a functioning packaging machine, the overhead pusher lug 
mechanism likely would be smaller and more compact relative to the size of 
the cartons than is shown in FIGS. 1-3. 
FIG. 1 illustrates an overhead pusher lug mechanism 11 comprising an 
endless flexible lug conveyor chain 12 that extends about an upstream 
sprocket 13 and a downstream sprocket 14. With this embodiment, the chain 
12 defines a lower flight 16 and an upper flight 17. 
The mechanism 11 is designed to be incorporated in and function with an 
article packaging machine wherein cartons 18 are conveyed and spaced 
sequential relationship along a carton path in the direction indicated by 
arrows 19 in FIG. 1. Usually, the cartons 18 are supported on a carton 
conveyor mechanism 21 having arrays of spaced upstanding lugs 22 that 
space and push the cartons along the path. 
Since the cartons 18 usually are open as they move along the path, they can 
be rather flimsy. As a result, and since modern packaging machines operate 
at high rates of speed, the top portions of the cartons tend to lag a bit 
behind the lower portions, causing the cartons to become skewed and 
deformed as they move along the carton path. This, in turn, can cause 
articles such as beverage containers to impact the sides of the deformed 
cartons as the articles are inserted into the cartons, causing the cartons 
to crumple, requiring shut-down of the machine for clean-out. As discussed 
above, the present invention functions to stabilize and push along the top 
portions of the cartons to maintain the square geometry of the cartons and 
avoid problems resulting from misinsertion of articles into deformed 
cartons. 
The lower flight 16 of the endless conveyor chain 12 is positioned to 
extend just above the tops of cartons 18 on the carton conveyor and is 
oriented along the direction of carton movement on the path. One or both 
of the sprockets 13 and 14 is driven by an appropriate drive motor (not 
shown) to move the lower flight 16 of the chain in the same direction as 
carton movement and at a rate that is synchronized with the rate at which 
the cartons are conveyed along their path. 
A plurality of generally triangular pusher lugs 23 are pivotally mounted at 
spaced intervals along the endless conveyor chain 12. The details of each 
pusher lug and its attachment to the chain are described more fully below. 
In general, however, each lug is pivotable or rotatable between a first 
position in which the lug extends inwardly of the conveyor mechanism as 
illustrated on the upper flight of the chain in FIG. 1, and a second 
position wherein the lug extends outwardly and away from the conveyor 
chain as illustrated on the lower flight of the chain in FIG. 1. The lugs 
are spaced apart a distance corresponding to the distance between the 
trailing sides of adjacent cartons on the path. That is, they are spaced 
apart a distance corresponding to the spacing of lugs on the carton 
conveyor. Further, the chain 12 is synchronized relative to the carton 
conveyor mechanism so that the lugs on the lower flight 16 extend 
downwardly and into the spaces between adjacent cartons on the path and 
bear against the upper trailing edge portions of cartons as the cartons 
move along the path. Since the chain is driven to move its lower flight 16 
at the same rate as the cartons, the lugs move along with the cartons and 
support their top trailing edges to stabilize the cartons and prevent them 
from lagging and becoming deformed as they move along the carton path. As 
a result, the cartons are held square and articles can be inserted with a 
greatly reduced risk of misinsertion. After the articles are inserted, the 
cartons move on beyond the overhead pusher lug assembly 11 where they are 
sealed and pass away from the packaging machine. 
A rigid elongated retainer rod 24 extends along and just above the lower 
flight 16 of the conveyor chain 12. The rod 24 is vertically aligned with 
the pusher lugs 23 and has a contoured end portion 26 disposed at the 
upstream end of the pusher lug mechanism. The end portion 26 is formed 
with a point that is positioned to engage the lugs as they move around the 
upstream sprocket 13 and onto the lower flight 16 of the chain 12. As 
illustrated by arrows 27 in FIG. 1, when a lug in its first position 
engages the point of the rod 24, the lug is forced by continued movement 
of the chain to rotate or pivot from its first inwardly extending position 
to its second outwardly projecting position. The contoured end portion 26 
of the rod 24 has a curved lower surface 28 that is configured to continue 
and complete the rotation of the pusher lugs as they complete their 
movement around the sprocket 13 and move onto the lower flight 16 of the 
chain 12. Since the chain is driven in synchronization with the cartons 
18, this rotation or flipping of the pusher lugs causes the lugs to flip 
into position between two cartons and come to rest against the upper 
trailing edge of the forward carton. The rotational flipping of the pusher 
lugs in conjunction with the synchronized movement of the chain causes the 
lugs to be inserted neatly between adjacent cartons as each lug completes 
its movement around the upstream sprocket to avoid impact between the lugs 
and the leading top portions of trailing cartons on the conveyor. As a 
result, the lugs can be made as long as reasonably necessary without 
danger of their impacting and deforming cartons on the conveyor as they 
move around the sprocket and into place between the cartons. 
Once a lug has been completely flipped into position by the end portion 26 
of the rod 24, it moves onto and along the lower flight 16 of the conveyor 
chain 12. In doing so, the lug bears against the upper trailing edge of a 
carton to stabilize the carton for insertion of articles. To prevent the 
lugs 23 from being flipped back toward their first positions by the force 
of the cartons, the upper legs of the lugs bear against the bottom of the 
rod 24 as the lugs move along the lower flight 16. The retainer bar 24 
thus holds the lugs securely in their second positions extending 
downwardly between the cartons all along the length of the lower flights 
16. Thus, the top portions of the cartons 18 are firmly stabilized by the 
lugs 23 such that articles can be inserted without incident. 
Once cartons have moved along the carton path and articles have been 
inserted into the cartons, there no longer is a need to support the top 
portions of the cartons. At this point, the lugs 23 move beyond the 
retainer bar 24 and upwardly around the downstream sprocket 14 to the 
upper flight 17 of the chain 12. A pivot block 28 is disposed along the 
upper flight 17 of the chain 12 and is positioned to engage the pusher 
lugs 23 as the lugs move back along the upper flight. When the lugs 23 
engage the pivot block 28 they are forced by continued movement of the 
chain to rotate as indicated by arrows 29 back to their first positions 
extending inwardly of the endless conveyor chain 12. The pusher lugs are 
thus "reset" in preparation for their next entry onto and traverse along 
the lower flight 16 of the chain. The pivot block 28 is positioned in FIG. 
1 to engage and reset the pusher lugs just as they leave the downstream 
sprocket 14. It will be understood, however, that the pivot block can be 
located at any convenient position along the chain so long as the lugs 
engage the pivot block and are reset prior to being flipped back into 
position by the end 26 of the retainer bar 24. 
FIG. 2 illustrates in perspective form and in more detail an overhead 
pusher lug assembly preferred for use in an actual packaging machine. The 
assembly 11 comprises tandem endless conveyor chain mechanisms 12, each of 
which is a mirror image of the other and functions substantially as 
described above with respect to FIG. 1. Each of the endless conveyor 
chains is provided with spaced pusher lugs 23 that are pivotally mounted 
along a chain. The upstream sprockets 13 and downstream sprockets 14 are 
supported by metal plates 31 and tension arms 32 to maintain the chains 12 
in a tight relationship about the sprockets 13 and 14. A drive shaft 33 is 
rotatably journaled in appropriate bearings 34 and is fixed to the 
downstream sprockets 14. The drive shaft 33 is driven by an appropriate 
drive motor (not shown) to rotate the downstream sprockets 14 in the 
direction of arrow 36 to drive the endless chain conveyors as described. 
The drive shaft 33 is driven at the rate required to move the lower flight 
16 of the chains 12 in synchronization with the cartons 18 on the carton 
path. 
Each of the endless conveyor chain mechanisms is provided with elongated 
retainer rods 24 having end portions 26 that engage and flip the pusher 
lugs into position between cartons on the carton path. In addition, each 
of the endless chain conveyors is provided with a pivot block 28 
positioned to engage and reset the pusher lugs 23 to their first inwardly 
extending positions as shown. 
As discussed above, most article packaging machines are adapted to operate 
with cartons of more than one size. For example, in a beverage container 
packaging machine, it is common for the machine to be able to accommodate 
six, twelve, and twenty-four-pack cartons of beverage containers. By way 
of example, six-pack beverage cartons typically are approximately 51/4 
inches wide while twelve-pack cartons typically are approximately 111/4 
inches wide. The cartons are commonly spaced approximately 3/4 inch apart 
on the carton conveyor. Accordingly, it is necessary for the pusher lugs 
of the overhead pusher lug assembly to be spaced apart six inches when 
accommodating six-pack cartons and to be spaced apart 12 inches when 
accommodating twelve-pack cartons. 
To accommodate different size cartons without the necessity of removing and 
reorganizing pusher lugs on the endless conveyor chains, the pusher lugs 
in one preferred embodiment of the present invention are arranged along 
their chains in a first longitudinally aligned array and a second 
longitudinally aligned array that is laterally displaced relative to the 
first array. In addition, two side-by-side retainer bars 24 extend along 
the lower flight of each chain with the first bar being vertically aligned 
with the first array of pusher lugs and the second bar being vertically 
aligned with the second array of pusher lugs. With this configuration, 
each of the arrays of pusher lugs and its corresponding retainer bar 
functions independently of the other array for insertion of the lugs of 
the array into place between cartons on the carton conveyor. 
In the preferred embodiment, one or both of the retainer bars 24 is 
retractable up and away from its associated pusher lug array. When the bar 
is retracted, it does not engage the ends of the lugs of its corresponding 
array when the lugs move around the upstream sprocket and onto the lower 
flight of the conveyor chain. Accordingly, the lugs of that array stay in 
their first or inoperative positions extending inwardly of the conveyor 
chain and have no affect on cartons beneath the assembly. 
With the just described arrangement, it can be seen that with both of the 
retainer bars in their lowered operable positions, each of the adjacent 
lugs along both arrays on the conveyor chain is flipped into position 
extending between the cartons on the carton conveyor. However, when one of 
the retainer bars is retracted, the lugs of its array are not affected and 
only the lugs of the other array are flipped into position. Thus, with 
this arrangement, only every other lug on the chain is flipped into 
position between cartons on the carton conveyor. 
As an example, with the six and twelve inch wide cartons mentioned above, 
adjacent lugs are spaced apart six inches along the chain, the lugs in 
each separate array being spaced apart twelve inches. Thus, when both 
retainer bars are in their operable positions, all of the lugs in each 
array are flipped down to accommodate cartons spaced at six inch 
intervals. However, when accommodating twelve inch interval cartons, one 
of the elongated retainer bars is retracted so that only one of the lug 
arrays is flipped to provide overhead pusher lugs at twelve inch 
intervals. Thus, the overhead pusher lug assembly of this invention is 
quickly and easily adaptable to two different sized cartons simply by 
proper placement of the elongated retainer bars that flip the lugs 
downwardly between the cartons. 
FIG. 3 illustrates the off-set pusher lug arrays and corresponding retainer 
bars for each array. In FIG. 3, one of the retainer bars is shown 
retracted to adapt the overhead pusher lug assembly for operation with 
wider cartons. As with FIG. 1, the conveyor chain 12 is seen to bear a 
plurality of triangular shaped pusher lugs 23 rotatably attached at spaced 
intervals to the chain. Alternating ones of the pusher lugs 23 are spaced 
from the chain 12 by a spacer block 37. The spacer blocks 37 preferably 
are formed to be slightly wider than the pusher lugs 23. In this way, the 
lugs 23 are arranged on the chain 12 into a first longitudinally aligned 
array comprising the pusher lugs mounted directly to the chain and a 
second longitudinally aligned array comprising the lugs mounted on the 
spacer blocks 37. The second longitudinally aligned array of pusher lugs 
is laterally displaced by the spacer blocks 37 relative to the first array 
of pusher lugs. Thus, the lugs of the first array and the lugs of the 
second array move in distinctly different and independent paths as the 
chain is driven about its sprockets. 
A first elongated retainer bar 24 extends along the lower flight of the 
chain conveyor and is vertically aligned with the first array of pusher 
lugs. The end portion 26 of the bar 24 is positioned, as in FIG. 1, to 
engage the pusher lugs as they move onto the lower flight of the conveyor 
and flip them as indicated by arrows 38 into position between adjacent 
cartons on the carton path. With this arrangement, the pusher lugs in the 
first aligned array of lugs are flipped and held in their operable 
positions as they move onto and along the lower flight of the conveyor 
chain. 
A second elongated retainer bar 39 having a contoured end 41 extends along 
the length of the lug conveyor and is vertically aligned with the pusher 
lugs in the second array mounted on spacer blocks 37. In FIG. 3, the 
second retainer bar 39 is shown in its retracted position displaced from 
the lugs as they move along the lower flight of the conveyor. With the 
second retainer bar in this position, the lugs of the second array are not 
engaged and flipped over as they move on to the lower flight of the 
conveyor. Thus, the lugs of the second array remain in their inoperable 
inwardly extending orientations as shown at 42 as they move onto and along 
the lower flight of the conveyor chain. Thus, the lugs in this array have 
no affect on cartons moving along the path when their corresponding rod 39 
is in its retracted position as shown in FIG. 3. 
Conversely, however, when the second elongated retainer rod 39 is moved 
downwardly into its operable position adjacent to the rod 24, it engages 
the pusher lugs of the second array and flips them over as well into their 
downwardly extending operable positions as they move on to the lower 
flight. With such a configuration, every lug on the conveyor chain is 
flipped downwardly as it moves on to the lower flight to accommodate 
narrower cartons that are spaced along the carton conveyor a distance 
corresponding to the distance between adjacent lugs on the overhead pusher 
lug assembly. With the retainer bar 39 retracted as shown in FIG. 3, the 
overhead pusher lug assembly is adapted to accommodate wider cartons 
spaced along the carton conveyor a distance corresponding to the distance 
between every other lug on the overhead pusher lug assembly. It can thus 
be seen that the overhead pusher lug assembly of this invention is quickly 
and easily adaptable to narrower and wider cartons simply by raising or 
lowering the second elongated rigid bar 39 as necessary. 
Although not shown in FIG. 3, it will be understood that, like FIGS. 1 and 
2, the pusher lugs are reset back to their first inwardly extending 
positions by appropriately positioned pivot blocks mounted on the 
assembly. In this way, all of the lugs are reset at the top of the 
assembly in preparation for the proper orientation as they move onto and 
along the lower flight of the assembly. 
FIGS. 4, 5, and 6 illustrate the detail construction of the overhead pusher 
lugs 23 and the mounting of the lugs to the conveyor chain 12. Each of the 
pusher lugs 23 preferably is formed of a rigid durable plastic material 
and has a generally right triangular shape. The lug 23 is formed with a 
through-bore 43 at the apex of the triangle and a crescent notch 44 that 
is spaced from and concentric with the through-bore 43. The lug 23 is 
adapted to be rotatably or pivotally secured to a link of the chain 12 by 
means of a link plate 46 and a pair of link pins 47. The link plate 46 has 
a pair of spaced holes 48 that align with the through bore 43 and notch 44 
so that the link pins 47 extend through the link plate 46 and through the 
bore and notch of the pusher lug 23. The pins 47 continue through the link 
of the chain 12 and are secured on the back thereof to mount the pusher 
lug to the chain. If the pusher lug is a member of the first 
longitudinally aligned array of lugs, it is mounted directly to the link 
of the chain 12. Conversely, if it is a member of the second 
longitudinally aligned array that is laterally displaced from the first 
array, a spacer block 49 having a pair of appropriately spaced holes is 
disposed between the pusher lug 23 and the link of the chain 12. 
The crescent notch 44 in the pusher lug 23 has a detente 51 formed adjacent 
one end. The pusher lug in FIG. 4 is shown as it would appear on the lower 
flight of the conveyor chain and in its second or downwardly extending 
orientation. The detente 51 is sized and positioned such that when the 
pusher lug 23 is rotated in the direction of arrow 52 back to its first or 
inoperative position, the pin 47 within the crescent notch 44 snaps into 
place behind the detente 51 thus releasibly securing the pusher lug in 
place. Accordingly, and referring to FIG. 1, when the pusher lugs 23 
encounter the pivot block 28, they are rotated back to their first 
positions and snap in place there by virtue of the detentes 51. As the 
pusher lugs move on around back toward the lower flight of the conveyor 
chain, the force of the engagement between the lugs and their respective 
retainer bars 24 and 39 dislodges the pins 47 from the detente 51 and 
rotates the pusher lugs back to their second downwardly extending operable 
positions. 
FIG. 5 is an end view looking along the lower flight of the conveyor chain 
in FIG. 1. The pusher lug 23 is shown mounted to the chain 12 by means of 
link plate 46 and link pins 47. The pusher lug 23 is in its second 
downwardly extending position for engaging and stabilizing cartons on a 
carton path below. The pusher lug 23 rides along the lower surface of 
elongated retainer rod 24, which holds the pusher lug 23 in its downwardly 
extending position and prevents it from being moved or rotated back up as 
a result of the force exerted on the lug by the cartons. 
FIG. 6 illustrates a view along the lower flight of the conveyor chain in 
the embodiment of FIG. 3 with the second retainer bar 39 shown in its 
downward operable position. The first aligned array of pusher lugs 23 are 
seen to be rotated to their downwardly extending positions riding just 
under the first elongated retainer bar 24. Similarly, the second 
longitudinally aligned array of pusher lugs 23 are seen to be fixed to the 
chain conveyor 12 by means of a link plate 46, link pins 47, and a spacer 
block 37. This array of pusher lugs is also seen in its downwardly 
extending operable position riding just below the lower edge of the second 
retainer bar 39. It will be understood that, in this orientation, the 
overhead pusher lug assembly is set up to accommodate narrower cartons 
having a width corresponding to the distance between adjacent pusher lugs 
on the conveyor chain. 
FIG. 7 is an end view of the overhead pusher lug assembly of this invention 
as seen from the upstream end thereof. The conveyor chains 12 are seen to 
be provided with pusher lugs 23 that are arranged in a first 
longitudinally aligned array adjacent to the chains and a second 
longitudinally aligned array spaced from the chains by spacer blocks 49. 
Each of the arrays of pusher lugs are laterally off-set from one another 
by a predetermined amount. The elongated retainer bars 24 and 39 are shown 
in their down or operable positions to rotate each pusher lug of the 
assembly into its downwardly extending operable position. The retainer 
bars 39 are coupled to the retainer bars 24 by means of a retracting 
mechanism 53, which allows the bars 39 to be raised upwardly and locked in 
an inoperable position if desired. The retracting mechanisms 53 can be of 
any appropriate type such as the L-bracket and pin arrangement of FIG. 7A. 
With such an arrangement, the second elongated rods 39 can simply be 
lifted up and to the left in FIG. 7A, whereupon their pins lock into place 
within the horizontal portions of the grooves. Pivot blocks 28 are seen in 
FIG. 7 to be positioned so that they engage the pusher lugs of both arrays 
along the upper flight of the pusher lug assembly to rotate and snap the 
pusher lugs back into their inwardly extending inoperable positions before 
they move back around to the lower flight of the pusher lug assembly. 
The invention has been described herein in terms of preferred embodiments 
and methodologies. It will be understood by those of skill in this art, 
however, that the illustrated embodiments are exemplary only and that the 
invention is not limited by the particular configuration and features 
thereof. Numerous additions, deletions, and modifications might well be 
made to the illustrated embodiments without departing from the spirit and 
scope of the invention as set forth in the claims.