Infeed conveyor with multiple flight capability

A product feed device includes multiple drivers mounted pivotally between a pair of parallel and opposed endless chains. When pivoted to an active position, each driver engages a product and pushes the product along a path. A set of cams is disposed upstream of the path. Each of the cams is alternatively positionable in alignment between the chains, to engage successive drivers to either set or reset the drivers as they encounter the cam. The cams set and reset successive drivers in different repeating sequences, thus to enable switching from one selected spacing between actuated cams to another, depending on which cam is in the operating position. A pair of opposed guide members extend longitudinally along the path to confine the chains against transverse movement, and maintain each of the drivers in its selected orientation, whether set to active or reset to a bypass position.

BACKGROUND OF THE INVENTION 
This invention relates to devices for handling and transporting 
substantially identical objects in series, and more particularly to 
conveyors for delivering food items or other products at controlled 
intervals for automatic packaging. 
Endless conveyors, particularly in the form of chains, are frequently 
employed to move a wide variety of solid materials. For example, a chain 
scraper conveyor for transporting granular and abrasive material is 
disclosed in U.S. Pat. No. 4,815,586 (Heising). More particularly, a pair 
of parallel chains carries spaced apart drivers through a trough to carry 
particulates through the trough. Rollers in the trough support the drivers 
and reduce friction. 
U.S. Pat. No. 4,353,276 (Ackerfeldt) discloses an infeeding conveyor for 
work pieces to be cut by a stationary sawing machine. The conveyor 
includes two independently driveable endless chains, with at least one 
dogging means mounted to each chain. As one of the chains and dogging 
means feeds a log toward the saw, another one of the chains can be moved 
to align its dogging means for receiving the next log to be cut. 
In many applications it is desirable to provide controlled, consistent 
spacing between adjacent drivers or pushers, to accommodate a series of 
substantially equally sized objects. In this regard, the most direct 
approach is to permanently secure the drivers, equally spaced apart from 
one another a distance slightly greater than the length of the objects to 
be conveyed. A device capable of limited adjustment of this spacing is 
disclosed in U.S. Pat. No. 3,198,316 (Bivans). A pair of endless chains, 
one carrying spaced apart leading fingers and the other carrying spaced 
apart lagging fingers, interact with sprocket for tilting the lagging 
finger backward to increase the size of the space for receiving the box, 
affording greater tolerance for a device that feeds the boxes to the 
conveyor. 
With automatic packaging or wrapping of products, the need arises to feed 
items at controlled intervals for wrapping, and preferably at high speed. 
Horizontal wrapping machines, for example as disclosed in U.S. Pat. No. 
4,506,488 (Matt et al), typically involve drawing and shaping a continuous 
film of pliable packaging material into a continuous tube that receives a 
series of spaced apart food items or other products to be packaged. The 
tube is drawn past sealing and cutting stations to individually package 
the products. 
The introduction of computer controlled and servo motor operated drawing, 
sealing, cutting, etc. in wrapping devices affords the ability to 
pre-program product changeovers, which is a considerable advantage. 
However, a changeover to a product of different size traditionally has 
required a corresponding adjustment to the infeed conveyor to the wrapping 
device. Usually, this involves replacing one chain or endless conveyor 
with another conveyor having the appropriate spacing between pushers. Thus 
the changeover is time consuming and costly since the packing device can 
not operate during the changeover. 
Therefore, it is an object of the present invention to provide an endless 
conveyor carrying multiple drivers along its length, in which selective 
subsets of the drivers can be actuated for controllably varying the 
distance between adjacent actuated drivers. 
Another object is to provide a chain conveyor in which drivers carried by 
an endless chain are actuated by a means traveling approximately the same 
speed as the chain. 
A further object of the invention is to provide, in connection with an 
endless chain carrying multiple actuatable drivers, a means for positively 
actuating or positively retracting each driver as it approaches a path for 
conveying objects. 
Yet another object is to provide an endless chain drive with multiple 
drivers configured to avoid off-center loading of the drivers, and with 
guide means for substantially preventing movement of the endless chain 
normal to the direction of chain travel. 
SUMMARY OF THE INVENTION 
To achieve these and other objects, there is provided an apparatus for 
conveying objects in a series along a selected path and with controlled 
spacing between successive objects in the series. The apparatus includes a 
stationary support structure having a support surface for supporting 
objects by gravity for movement along a selected path. An endless conveyor 
means is mounted on the support structure such that a portion of the 
length of the conveyor means runs along and adjacent the selected path. A 
moving means is provided for moving the endless conveyor means relative to 
the support structure. A plurality of drivers are mounted to the endless 
conveyor means and spaced apart from one another along the length of the 
conveyor means. Each of the drivers is mounted to reciprocate relative to 
the conveyor means between an active position for engaging one of the 
objects to move the object along the selected path with the conveyor 
means, and a bypass position wherein the driver does not engage the 
object. 
A first driver control means is mounted movably to the support structure 
near one end of the path. The control means includes a setting means for 
engaging at least first selected ones of the drivers as they are carried 
toward the path by the conveyor means, thus to urge the first selected 
drivers into the extended position for moving the object along the path. A 
governing means moves the control means relative to the support structure 
such that the setting means, when it engages the first selected drivers, 
is moving at approximately the same speed as the endless conveyor means. 
The preferred control means is a cam mounted rotatably to the support 
structure. The cam has a plurality of radially extended lobes, with 
setting means comprised of setting surfaces at the radially outward ends 
of the lobes. The cam is rotated so that the tangential speed of the lobe 
outward ends substantially matches the linear speed of the endless 
conveyor. Accordingly, even at high conveyor speeds, control of the 
drivers is smooth, with minimal shock or vibration, due to the matching of 
the cam and conveyor speeds. 
Another aspect of the invention involves providing a second driver control 
means, also mounted movably to the support structure near the same end of 
the path. The second control means has its own setting means for engaging 
second selected ones of the drivers to urge them into the active position. 
A selection means mounts both the first and second control means to the 
support structure. The selection means is operable to selectively position 
either the first or second control means in position to engage its 
associated selected drivers, while the other control means remains free of 
the drivers. 
Consequently, either of two alternate schemes for selecting drivers can be 
employed with the endless conveyor, simply through adjusting the selection 
means. This enables the spacing between actuated or extended drivers to be 
adjusted "on the fly", without disassembling and replacing the conveyor. 
According to yet another aspect of the invention, each of the control means 
can include a resetting means in addition to the setting means. The 
resetting means engages all drivers other than the selected drivers 
(engaged by the setting means) as they are carried toward the path, to 
urge such other drivers into the bypass position. Accordingly, all drivers 
are positively adjusted, either to the active position or to the bypass 
position, for a substantially improved and smoother operation, 
particularly at high speeds. Thus, it becomes practicable to operate at 
speeds where depending on gravity to retract drivers has been found 
unsatisfactory. 
According to another aspect of the present invention, the endless conveyor 
means includes a pair of endless chains mounted to the support member in 
parallel, spaced apart relation to one another. The moving means is 
operably coupled to the chains and to the support structure, and moves the 
chains in concert with respect to the support structure. Each of the 
drivers is centrally disposed between the two chains, and secured to both 
of the chains. This arrangement avoids off-center loading on the drivers 
as they move objects along the path, and accordingly reduces the load on 
the chain. This also permits the chains to be substantially shielded from 
objects being moved along the path by the drivers, to protect the chains 
from debris generated by the objects. More particularly, the support 
structure can include a pair of opposed channels along the path, each of 
the channels substantially enclosing one of the chains to substantially 
prevent the chain from displacement perpendicular to its direction of 
travel along the path. Guide flanges, also running along the path, capture 
the drivers to positively maintain each driver, either in the active 
position or the bypass position, as it traverses the path. 
Thus, the present invention encompasses a variety of improvements to an 
endless conveyor carrying multiple drivers for moving objects along a 
path, to enable substantially higher speed operation than is practical 
under conventional approaches, and further to enable precise control and 
adjustment of the spacing between adjacent drivers along the conveyor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Turning now to the drawings, there is shown in FIG. 1 a product handling 
and packaging system 16 including a bin 18, an in-feed device 20 for 
conveying a product as a series of equally spaced apart individual items 
22, and an automatic packaging device 24, also known as horizontal 
wrapper, for receiving and packaging the items. Items 22 can be candy bars 
supported on creased cardboard trays. Alternatively, the items can be any 
solid objects (other than particulate or granular) capable of being pushed 
or driven by the infeed device and wrapped by packaging device 24. 
Feed device 20 includes a stationary and rigid support structure including 
a table 26, a plurality of legs 28 secured to the table, and horizontal 
support bars attached to the legs including a bottom bar 30 and an 
inclined bar 32. Uprights 34 are secured to the table and to the inclined 
bar. Table 26 is substantially horizontal, but also has a trough or 
channel along its length, providing a longitudinal path along which 
product items 22 travel toward packaging device 24. 
An endless conveyor 36 is mounted for movement relative to the support 
structure by the series of rotatable sprocket assemblies, two of which are 
shown at 38 and 40. Conveyor 36 is somewhat triangular, with an upper 
horizontal portion running along the path (i.e. along the length of table 
26) and a lower inclined portion just above inclined bar 32. Endless 
conveyor 36 carries a plurality of drivers or pushers 42, spaced equally 
apart from one another along the length of the conveyor. Each driver 42 
shown in FIG. 1 is engaged with the rearward end of a product item 22, 
thus to push its associated product item along the path as a motor 44 
drives the conveyor via one of the sprocket assemblies. The spacing 
between successive drivers 42 is just slightly larger than the length of 
product items 22, to afford optimum control of the spacing between 
successive items as the product is fed in series to packing device 24. The 
drivers preferably are formed of a material selected for toughness, e.g. 
Hytrel or Delron brand polyesters, or metal such as stainless steel. 
Packaging device 24 includes a frame 46 supporting a horizontal table level 
with table 48 level with the table 26 of the feed device. Two supply rolls 
at 50 and 52 alternatively provide a continuous film 54 of packaging sheet 
material to a forming station 56 where the sheet material is formed into a 
continuous tube. Product items 22 are fed in series into the tube, and 
move with film 54 through a sealing and cutting station 58, where the 
continuous tube is formed into individual packages or wrappers, one 
enclosing each of the product items. The details of the packing device are 
not further discussed herein. For more information about this type of 
device, reference is made to the aforementioned U.S. Pat. No. 4,506,488 
(Matt et al). 
As seen in FIG. 2, table 26 includes two table sections 60 and 62 
symmetrical about a vertical plane. Respective vertical walls 64 and 66 
depend downwardly from respective top surfaces 68 and 70 of the opposed 
sections. Respective horizontal ledges 72 and 74 project transversely 
toward one another, and together provide a support surface for product 
items 22 as they traverse the longitudinal path. A central gap between the 
ledges runs the length of the path. Table sections 60 and 62 preferably 
are formed of stainless steel Delron brand polyester or other material 
suitable for contact with food. 
As seen in FIG. 2, sprocket assembly 40 includes two parallel and spaced 
apart sprockets 76 and 78 mounted to rotate in concert on a shaft 80. 
Conveyor 36 includes a pair of endless chains 82 and 84, generally known 
as roller chains, parallel and spaced apart from one another on opposite 
sides of the central vertical plane. 
Two opposed guide members 86 and 88 run the length of the path. The guide 
members are substantially uniform in transverse profile, and preferably 
are formed of polyester or other suitable polymer to provide durability 
and smooth, tough, low friction surface. Each of guide members 86 and 88 
is formed to provide an elongate channel, as indicated at 90 and 92, 
respectively. The channels are large enough to accommodate lobes (not 
shown) mounted on chains 82 and 84 for proximity sensing. Opposed rails 94 
and 96 extend vertically into channel 90, while corresponding rails 98 and 
100 project vertically into channel 92. Respective flanges or shelves 102 
and 104 of the guide members project toward one another. 
The manner in which the endless chains and drivers are confined within the 
guide members is shown in FIG. 3. The links of endless chains 82 and 84 
are substantially identical, each including a central barrel portion 
between two edge portions slightly wider than the barrel diameter. With 
reference to endless chain 82, rails 94 and 96 project toward a barrel 106 
between edge portions 108 and 110, and thus confine the chain against any 
transverse movement, both in the vertical and horizontal directions as 
viewed in FIG. 3. Rails 98 and 100 similarly confine chain 84 within 
channel 92 of guide member 88. 
Guide members 86 and 88 further serve to control the orientation of drivers 
42 as they proceed along the path toward packaging device 24. More 
particularly, flanges or shelves 102 and 104 cooperate with guide 
extensions of the drivers to orient the drivers as desired. Each driver is 
secured to both chains 82 and 84 and aligned centrally between the chains, 
as is shown for driver 42a in FIG. 3. As seen in FIGS. 4a and 4b, driver 
42a is mounted pivotally to chains 82 and 84 through a pin 112. The driver 
has a somewhat triangular body 114, a stem 116 extended from the body, a 
lug 118 extended from the body opposite the stem, and a pair of opposed 
extensions 120 and 122 projected transversely outwardly of the body. Pin 
112 is mounted to one of the links of chain 82, and to one of the links of 
chain 84. 
An arcuate slot 124 is formed in driver 42a. A pin 126, extending through 
the slot and mounted to one of the links of each chain, limits the degree 
of driver pivoting with respect to chains 82 and 84. 
In FIGS. 3 and 4a, drive 42a is shown in an active position in which it can 
move one of product items 22 along the path as motor 44 drives chains 82 
and 84. Guide extensions 120 and 122 are disposed above flanges 102 and 
104, which prevents driver 42a from pivoting out of the active or driving 
position. 
FIG. 4b shows driver 42a in the retracted or bypass position, in which it 
can not engage product items supported on ledges 72 and 74. Guide 
extensions 120 and 122 are captured below their respective flanges 102 and 
104, maintaining the driver in the bypass position. 
In FIG. 5, the rearward end of feed device 20 is shown with table 26 
removed, to illustrate a driver control assembly 128. Control assembly 128 
is located immediately upstream of the path, and determines the 
orientation of drivers 42 as they enter the path. The control assembly 
includes a box-like frame 130 mounted to pivot about sprocket supporting 
shaft 80 relative to the stationary support structure. Frame 130 includes 
a pair of opposed side plates 132 and 134 and a forward plate 136, and has 
an open bottom. Shaft 80 rotates relative to the side plates through 
bearing assemblies 138 and 140. Sprockets 76 and 78 rotate with the shaft. 
A cam shaft 142 is journaled to the side plates through bearing assemblies 
at 144 and 146. Mounted to shaft 142 for rotation therewith are a pair of 
spaced apart driver controlling cams 148 and 150. A timing belt or chain 
152, trained on pulleys 154 and 156 on shafts 142 and 80 respectively, 
driveably engages the shafts so that they rotate at the same speed. It is 
to be understood that any desired linear relationship of the shaft speeds 
can be obtained through proper selection of the pulleys. In the present 
case, the diameter of cams 148 and 150 is substantially equal to the 
diameter of sprockets 76 and 78, so that these components have 
substantially the same tangential speed. 
Between cams 148 and 150, shaft 142 is surrounded by a sleeve 158. A 
mounting plate 160 (FIG. 6) surrounds the sleeve, and is secured against 
transverse movement by an annular groove in the sleeve, in which plate 160 
is situated. 
An elongate arm 162 is mounted to pivot relative to frame 130 about a 
substantially vertical pivot axis. Mounting plate 160 is mounted to pivot 
relative to arm 162 about a substantially vertical axis by a pin 164 
integral with the mounting plate. Consequently, cams 148 and 150 and 
sleeve 158 slide along shaft 142 arm 162 pivots between its upper position 
as viewed in FIG. 5 along a broken line 166, and a lower position along a 
broken line 168. A slot 170 in the arm accommodates limited linear 
movement of mounting plate 160 relative to the arm. 
The forward portion of control assembly 128 is supported on a cross beam 
172 through a crank 174 rotatable on the beam about a longitudinal axis. 
Crank 174 supports the forward end of arm 162 through a bearing 176. Arm 
162 supports frame 130 by virtue of its containment in an elongate, 
transverse slot 178 through forward plate 136 (FIG. 8). 
Crank 174 when rotated carries arm 162, and thus cams 148 and 150, along an 
upwardly concave arcuate path indicated by a broken line 180 in FIG. 8. 
For the arm position shown in solid lines in FIG. 5, cam 148 is in the 
operative position, i.e. centered between sprockets 76 and 78 and 
positioned to engage drivers 42 as chains 82 and 84 carry the drivers from 
the right to the left as viewed in FIG. 5. Conversely, when arm 162 is 
located as shown in solid lines in FIG. 8, cam 150 is in the operative 
position. 
When arm 162 is intermediate the operating positions, the arm is pivoted 
counter clockwise as viewed in FIG. 7, bringing cams 148 and 150 downward 
so that the cams are clear of the drivers. Frame 130 pivots downwardly 
with arm 162, due to the containment of the arm within slot 178. Through 
this arrangement, both cams are disengaged from the drivers whenever they 
are being repositioned by crank 174. This facilitates changing cams on the 
fly, even when operating chains 82 and 84 at high speed, virtually 
eliminating down time when switching from one size of product item to 
another. 
FIGS. 9 and 10 schematically illustrate six drivers 42a-42f distributed 
radially about cam 148 and cam 150, respectively. It is to be understood 
that the drivers are in fact not distributed about the cams in this 
fashion. Yet, the illustrations facilitate explaining how the cams set the 
orientation of each drive member as it approaches the path. Cam 148 has 
three substantially identical lobes 182, 184 and 186. Lobe 182 has a 
setting end or surface 188 which, when it encounters body 114 of a drive 
member, sets the drive member in the active position (FIG. 4a). Lobe 182 
further includes a reset end or surface 190 which, upon encountering lug 
118 of one of the drivers, resets the driver into the retracted or bypass 
position. Lobes 184 and 186 have substantially identical setting and 
resetting edge portions. Thus, setting and resetting edge portions are 
distributed alternately about the cam circumference, spaced apart from one 
another by about 60 degrees. 
In actual operation, cam 148 rotates counter clockwise as viewed in FIG. 9 
while chains 82 and 84 bring successive drivers 42 into contact with the 
cam as they move from right to left. Successive drivers in the series are 
spaced equally apart from one another. Consequently, every other driver is 
set, as indicated by drivers 42a, 42c and 42e, while the alternate drivers 
42b, 42d and 42f are reset. Given a three inch spacing between consecutive 
drivers, this arrangement would accommodate product items five inches 
long, for example. 
FIG. 10 shows cam 150 to have four radially extended lobes at 192, 194, 196 
and 198. Lobes 192 and 196 are similar to the lobes of cam 148, with 
setting edges at 200 and resetting edges at 202. Alternate lobes 194 and 
198 have only resetting edges 204. This arrangement, again assuming a 
three inch spacing between successive drivers, would accommodate product 
items having a length of eight inches, with the spacing between set or 
actuated drivers being nine inches. 
In operation, feed device 20 accommodates a preprogrammed switch by 
packaging device 24 as follows. Assume that cams 148 and 150 are 
positioned as shown in FIG. 5, and candy bars five inches long are being 
supplied to packaging device 24 for wrapping. When a product changeover is 
desired, for example to an eight inch candy bar, crank 174 is pivoted to 
place cam 150 into the operative position. With every third driver rather 
than every other driver actuated, spacing between successive actuated 
drivers is increased from six inches to nine inches, without any need to 
reduce the speed of the chains, much less adjust or replace them. 
It is to be understood that cams 148 and 150 are disposed immediately 
upstream of guide members 86 and 88, so that flanges 102 and 104 capture 
each pair of guide extensions 120 and 122 almost immediately after the cam 
orients each driver. The guide members thus positively maintain each 
driver in its selected position, either active or bypass, along the entire 
length of the path. 
Certain features of the present invention are particularly advantageous 
when applied to high speed operations. For example, the various resetting 
edges positively position each rejected driver in the bypass position. The 
conventional approach has been to rely on gravity to maintain such drivers 
in the bypass position. The positive reset feature, and flanges that 
secure the drivers against drifting from either position, substantially 
enhance reliability and enable significantly increased chain speeds. 
Another feature particularly useful at high speeds relates to the fact that 
cams 148 and 150, when either setting or resetting the drivers, are moving 
at approximately the same speed as the drivers. In the present embodiment, 
this is due to the fact that shafts 80 and 142 rotate at the same speed, 
and that the cams and sprockets have the same diameter. This virtually 
eliminates the shock and vibration caused by inserting stationary tripping 
members into the path of the oncoming drivers. 
The chains and opposed guide members further enhance the utility of feed 
device at high speeds. The side-by-side arrangement of chains 82 and 84 
allows drivers 42 to be centered. This virtually eliminates off-center 
loading as the drivers push items along the path, which reduces the load 
on the chains and increases their useful life. Guide members 86 and 88 
along the entire length of the path, positively retain chains 82 and 84 
against undue vibration or transverse movement, further reducing wear to 
the chain. Also, as perhaps best seen in FIG. 3, the guide members 
substantially enclose the chains within respective channels 90 and 92, 
protecting the chains from food particles or other foreign matter. 
FIG. 11 illustrates a cam 206 that can be mounted upon shaft 142 in lieu of 
either one of cams 148 and 150. Cam 206 has six substantially identical 
lobes 208, spaced equally (30 degrees) apart from one another. Each of 
the lobes has a setting edge 210, and there are no resetting edges. 
Accordingly, cam 206 places every one of drivers 42a-f in the extended 
position, for pushing items less than three inches in length, again 
assuming a three inch spacing between successive drivers. 
FIG. 12 illustrates a driver control assembly for use in an alternative 
embodiment feeding device. A group of four cams 212, 214, 216 and 218 are 
mounted on a shaft 220, the shaft in turn being journaled in upright 
plates 222 and 224 of a frame 226. A servo motor 228 rotates shaft 220 
through a belt 230. 
Frame 226 is supported on a horizontal platform 232, with the platform in 
turn being slideable relative to stationary framework at 234 and 236. A 
pneumatic cylinder 238 is extensible and retractable to reciprocate 
platform 232 vertically as viewed in the figure. A motor 240 operates a 
worm gear 242 or the like to move frame 226 to the left and right as 
viewed in FIG. 12. Thus, motor 240 is operable to position any one of cams 
202-208 in alignment with a driver 244 secured to opposed chains 246 and 
248. Cylinder 238 is retractable to prevent the cams from engaging any of 
the drivers during switching of the cams. 
In this embodiment, there is no direct mechanical linkage between cam shaft 
220 and any of the sprockets that drive chains 246 and 248. Rather, a 
detector 250 senses movement of the chains, and provides a signal that 
indicates the chain velocity to servo motor 228 . Servo motor 228 responds 
to the signal in setting the shaft rotational velocity. As one example, 
suppose drivers 244 are spaced apart three inches from one another. Cams 
212, 214, 216 and 218 can be configured respectively to set every driver 
for three inch spacing, to set every other driver for six inch spacing, to 
set every third driver for nine inch spacing and to set every sixth driver 
for eighteen inch spacing between successive set drivers. In addition to 
rapid changes in spacing between active drivers, this arrangement affords 
an additional advantage in that chains 246 and 248, even for nine inch or 
eighteen inch spacing, can be adjusted as to their length in increments of 
three inches rather than nine or eighteen inches. 
Thus in accordance with the present invention, a feed device can be 
adjusted to handle products of different sizes on the fly, a particularly 
useful feature in connection with a packaging machine that can be adjusted 
on the fly to wrap different sized packages. Smooth setting and resetting 
of product drivers is provided, even at high speeds, by virtue of cams 
with setting and resetting edges moving at approximately the same speed as 
drivers carried by the chains. Positive setting and resetting of the 
drivers, in combination with guide members that maintain the drivers in 
their selected orientations, eliminate any drift of the drivers to further 
increase reliability at high speeds. The guide members further envelop the 
chains, substantially eliminating unwanted transverse movement, and 
protect the chain against contamination from debris. The dual chain 
arrangement also affords a balanced loading of the chain through the 
drivers.