Note: Descriptions are shown in the official language in which they were submitted.
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ACCUMVLATOR CONVEYOR
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A live roller accumulator conveyor commonly
includes a plurality of zones along the length of the
conveyor from the infeed to the discharge end
thereof, with each zone including powered rollers
adapted to receive an article from an immediately
upstream zone and deliver it to an immediately
downstream zone. A sensor associated with each zone
responds, under normal conditions, to the presence
of an article stopped therein by rendering
inoperative the powered rollers in the zone
immediately upstream therefrom.
In this manner, articles can back up from
the discharge end toward the infeed end of the
conveyor when a lead article is stopped in the
discharge zone. The zones are successively
deadened, i.e., the powered rollers therein are
successively rendered inoperative, from the
discharge end to the infeed ends as successive
articles are stopped in successive zones upstream
from the discharge end. Once the article at the
discharge end is removed, the zones are reactivated
to move the articles along the conveyor again. Such
conveyors, wherein the zones can be activated in
sequence, are shown in Vogt et al United States
Patent No. 4,108,303 and Vogt United States Patent
No. 4,109,783.
When it is desired to discharge accumulated
articles from a conveyor as shown in the Vogt et al
patent, each successive article must vacate the
particular zone wherein it had stopped before the
article stopped in the next zone upstream therefrom
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will begin to move. Thus although a plurality of
articles may be moving at the same time, adjacent
articles will be separated by a distance
substantially equal to the length of a zone. The
purpose of the present invention is to provide an
accumulator conveyor from which accumulated articles
can be discharged in groups, with minimal spacing,
if any, between the adjacent articles in each group.
Summary of the Invention
This invention provides an accumulator
conveyor in which, when an article stopped at the
discharge end has been removed, all of the zones in
a group of consecutive zones adjacent the discharge
end are activated in unison so that articles in all
1 the zones of the group are caused to advance in
unison and without waiting for the clearance of
individual downstream zones. In a preferred
embodiment of the invention, such an accumulator
conveyor is provided with fluid operated controls
which have valves arranged to cause actuation of
zones of an entire group when the upstream zone of
the adjacent downstream group is cleared.
Briefly, this invention provides an
; accumulator conveyor which includes a plurality of
zones arranged in groups. Each zone includes at
least one drive element, and a sensor located in
each zone is effective, when that zone is unoccupied
by an article, to actuate the drive unit for the
zone immediately upstream therefrom, and vice versa.
In order to accomplish the objective of
accelerated discharge of accumulated articles, the
invention provides secondary controls - in the form
o-f three-way valves and multiple pressure air lines
- which interconnect selected numbers of successive
zones into groups. When the accumulated articles
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are to be discharged, these secondary controls
override the sensor-operated controls in such manner
that even though all zones in the group may be
occupied by articles, the drive rollers for the
entire group of zones will be driven to cause all
articles accumulated in the group of zones to start
in unison toward the discharge end of the conveyor.
Similarly as soon as the sensor in the most upstream
zone of the group is released by a departing
article, all ~ones in the adjacent upstream group
are activated in unison, and so forth until all
accumulated articles have ~een set in motion.
Brief Description of the Drawings
Fig. 1 is a schematic view of the discharge
end portion of a conveyor constructed in accordance
with an embodiment of this invention, the conveyor
being free of articles
Fig. lA is a schematic view of a portion of
the conveyor upstream of the discharge end portion;
Fig. 2 is a schematic view of the discharge
end portion of the conveyor as a first article
enters the discharge end portion;
Fig. 3 is a schematic view of the discharge
end portion with a first article engaging a stop at
a discharge end of the conveyor;
Fig. 4 is a schematic view of the discharge
end portion with the first article engaging the stop
and a second article approaching the first article;
Fig. 5 is a schematic view of the discharge
end portion with the first two articles stopped at
the discharge end and a third article approaching
the first two articles;
- Fig. 6 is a schematic view of the discharge
end portion with the first three articles stopped
and a fourth article approaching the first three
articles;
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Fig. 7 is a schematic view of the discharge
end portion with four articles stopped and a fifth
article approaching the first four articles;
Fig. 8 is a schematic view of the discharge
end portion with the first five articles stopped;
Fig. 9 is a schematic view of the discharge
end portion with six articles stopped;
Fig. 10 is a schematic view of the
discharge end portion with the first article
starting to exit the conveyor;
Fig. 11 is a schematic view of the
discharge end portion with the first article having
substantially completed its exit and with the next
four articles moving in unison toward exit;
Fig. 12 is a schematic view of the
discharge end portion after the first article has
exited and showing the next four articles continuing
to move toward exit and a sixth article started in
motion;
Fig. 13 is a schematic view of the
discharge end portion showing a second article
exiting and other articles approaching the discharge
end of the conveyor.
Fig. 14 is a fragmentary plan view of the
conveyor;
Fig. lS is a fragmentary view in side
elevation of the conveyor with parts being broken
away to show details of construction; and
Fig. 16 is a view in section taken on an
enlarged scale on the line 16-16 in Fig. 14.
.
Detailed Description of the Preferred Embodiment
The accumulator conveyor 18 includes a
plurality of drive rollers 20 and idler rollers 22.
Friction drive wheels 24 are each arranged to engage
an associated pair of the drive rollers when in a
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raised position as indicated at 24U ~Fig. lA). Each
friction drive wheel is disengaged from the
associated drive rollers when in a lowered or
retracted position as indicated at 24Yl ~Fig. 2).
When air under pressure is introduced into the line
28, it a~ts in fluid pressure actuators 30D, 30Dl
and 30D2 (Fig. 1) to raise friction wheels 24D, 24Dl
and 24D2. The friction wheels are driven by an
appropriate drive mechanism shown in Figs. 14-16.
Details of the conveyor and the assemblies
which include the friction drive wheels 24 are shown
in Figs. 14-16. The conveyor includes side rails
114 and 116 supported by appropriate frame means,
not shown. Appropriate cross bars, not shown, hold
the side rails 114 and 116 in spaced parallel
relation. The drive rollers 20 and the idler
rollers 22 are rotatably mounted on shafts 118,
which span the side rails 114 and 116.
Each of the friction drive wheels 24 is
rotatably mounted in a housing 130 pivotally mounted
on a shaft 132 extending between the side rail 116
and a frame and guard member 134 which is connected
by an angle-shaped member 48 with the side rail
116. The housing 130 includes side walls 151 and
152, which are provided with openings 154 and 156,
respectively, in which a bearing support bolt 158 is
mounted. A nut 160, threaded on the bolt 158, holds
the bolt 158 in place. A bearing sleeve 162 is
mounted on the bolt 158 between the side walls 151
and 152. A ~riction wheel assembly 164 is rotatably
mounted on the sleeve 162.
The friction wheel assembly 164 includes a
hollow body 166 having a central portion 168, which
receives the bearing sleeve 162, and a sprocket
portion 170 integral with the central portion 168.
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The friction drive wheel 24 portion of the assembly
is a ring of rubber-like material mounted on the
body 166, and its perpheral face has driving
engagement with associated drive rollers.
; 5 The housing 130 carries a removable bottom
plate 174, which is slidably mounted on lower edge
portions of the side walls lSl and 152. A chain
guide rib 176 on the bottom plate 174 underlies the
sprocket portion 170 and serves to guide an upper or
drive chain course 172 into driving engagement with
the sprocket portion 170. The bottom plate 174 can
be removed to free the drive chain course from the
sprocket portion 170.
The housing 130 is raised by a diaphragm
lS 178 of qenerally inverted cup shape, which is a part
of the fluid pressure actuator 30 and is mounted on
a seat portion 180 of a plastic molding which is
mounted on the member 48 and includes a chain guide
portion 182 for the lower or return run 184 of the
drive chain. Air under pressure can be introduced
into the interior of the diaphragm 178 through a
port 196 to cause the diaphragm 178 to assume the
extended position shown in Fig. 16.
A sensor roller 38 (Figs. 14 and 15) is
rotatably mounted in idler fashion between opposed
bell crank arms 220. The sensor roller 38 is
mounted at the upper ends 221 of the bell crank arms
220, which are pivotally mounted to, but spaced
from, the side rails 114 and 116 on a pivot axis
222. A bar 226 is welded to and spans the bell
crank arms 220 to cause them to move as a unit. A
tension spring 228 urges the sensor roller 38 into a
sensing plane 229 with no articles on the conveyor.
The sensing plane 229 is elevated above a conveying
plane 216 defined by the drive rollers 20 and the
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idler rollers 22. A wear strip 232 is mounted on
one of the bell crank arms 220 to cooperate with a
sensor operated valve 36.
The structure described to this point is
similar to that shown in the aforementioned patents
Nos. 4,109,783 and 4,108,303, and in Vogt et al
application Serial No. 914,851, filed June 12,
1978. Air under pressure is supplied through a line
32 (Figs. 1-13). The air supply to the various
fluid pressure actuators is controlled by a
discharge valve 37 and sensor operated valves 36
which direct the air to air lines 42.
The conveyor is divided into a plurality of
zones, and these zones are divided into groups. At
the discharqe end of the conveyor is a discharge
zone 37. Upstream of the discharge zone is a series
of zones indicated Zl, Z2, Z3 and Z4 which are
interconnected into the Z group of zones by the
successive valves 36B, 36A and 36C, which cause
pressure air to be supplied to the drive assembly in
zones Z2, Z3 and Z4 irrespective of the positions of
sensors 38B, 38A and 38C whenever sensor 38D is
released.
Upstream of the last group of zones is a
next or Y group of zones (Fig. lA) indicated Yl, Y2,
Y3 and Y4 and similarly interconnected by valves
36F, 36G and 36H under the control of valve 36E.
Further upstream are additional similar groups of
zones, not shown in detail except for zone Xl in
Fig. lA. The flow of air to the fluid pressure rams
in each zone is controlled by a sensor 38 in the
zone immediately downstream therefrom.
Each sensor 38 actuates one of the series
of sensor operated valves 36. Thus the sensor 38A
located in the zone Z2 immediately downstream from
the zone Z3 actuates a valve 36A which controls flow
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of air to fluid pressure actuators 30Z3 in the zone
Z3. The valve 36A has a normal position shown in
` Fig. 1 in which the air line 32 is connected to a
line 42Z3. The line 42Z3, in turn, is connected to
~ 5 associated actuators rams 30Z3 to raise friction
: wheels 20A to drive the associated drive rollers of
zone Z3.
~ Valve 36D associated with the zone Zl,
::: which is the downstream zone of the Z group of
- 10 zones, normally is in the position shown in Fig. 1
~ ~:in which air under pressure from the line 32 is
: directed through a line 42Zl to raise friction
wheels 24Zl into driving engagement with drive
: rollers 20Zl in zone Zl. When an article L is
~5 stopped in the discharge zone 37 and the sensor 38D
: is:depressed as shown in Fig. 3, the valve 36D is in
:j~ its other position, and the line 42Zl is connected
to an exhaust line 44 so that the friction wheels
24Zl of the zone Zl are lowered and the drive
rollers 20Zl are released. A mechanical stop 46 can
stop article L in the discharge zone 37. Thus the
` drive rollers in the zone Zl are inactive when the
article L is stopped in the discharge zone 37.
: ~ The sensor 38B located in the zone Zl is
~ depressed by an article in zone Zl, as indicated in
Fig. 5, where an article M is shown in the zone Zl.
The sensor 38B actuates a valve 36B. When the valve
36B is in its normal position, as shown in Fig. 1,
the air pressure line 32 is connected to a line
. 30 42Z2:. The line 42Z2, in turn, is connected to
: actuators 30Z2 in the zone Z2 so that when there is
air under pressure in the line 42Z2, friction wheels
42Z2 in the zone Z2 are raised to drive associated
d~ive rollers 20Z2 in the zone Z2.
When there are articles in zone Zl and in
~: the discharge zone 37, as shown in Fig. 5, the valve
36B is in its other position, and the drive rollers
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in the zone Z2 are inactive. However, the line 42Zl
is connected to the valve 36B, and when the
discharge zone 37 is vacated as shown in Fig. 11 and
the sen~or 38D is in its raised or normal position,
air under pressure is introduced into the line 42Z2
to actuate the drive rollers in the zone Z2 even
though an article M is stopped and engaging the
sensor 38B in the zone Zl.
In similar fashion, the sensor 38A located
in the zone Z2 can be depressed by an article N
(Fig. 6) in the zone Z2 to actuate the valve 36A
controlling flow of air to the line 42Z3 and
actuation of the drive rollers 20Z3 in the zone Z3.
The sensor 38C located in the zone Z3 can be
depressed by an article O (Fig. 7) in the zone Z3 to
actuate the valve 36C controlling flow of air to a
line 42Z4 and actuation of drive rollers 20Z4 in the
zone Z4. The line 42Z3 is connected to the valve
36C, and when the sensor 38D in the discharge zone
37 is released as shown in Fig. 11, air under
pressure from the line 32 is directed through the
valves 36D, 36~, 36A and 36C to the lines 42Zl,
42Z2, 42Z3 and 42Z4 to cause actuation of the drive
rollers in zones Zl, Z2, Z3 and Z4 as shown in Fig.
11 and cause advance of articles in all of the zones
of the Z group of zones.
The sensor 38E, which is located in the
zone Z4, actuates a valve 36E. When the valve 36E
is in its normal position, as shown in Fig. lA, air
under pressure is directed from the line 32 to a
line 42Yl. When the sensor 38E is moved to its
lowered position by an article P in the zone Z4, as
shown in Fig. 11, the valve 36E is in its other
position, and the line 42Yl is connected to an
exhaust line 44A.
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The line 42Yl is connected to a valve 36F
(Fig. lA) which is actuated by a sensor 38F located
in the zone Yl. The valve 36E and valves 36G, 36
and 36F associated with the Y group of zones are
interconnected in the same manner as the valves of
the Z group so that when the sensor 38E is released,
air under pressure is directed through the valves
36E, 36F, 36G and 36 to cause actuation of the drive
rollers in all of the Y group of zones.
In similar fashion, sensor operated valves
of an X group of zones, only one of which is shown,
and additional groups of zones further upstr~am, can
be similarly connected so that when the sensor
operated valve controlling actuation of drive
rollers of the most upstream zone in a group of
zones is in its normal position, air under pressure
is directed to all zones in the next upstream group
of ~ones. Thus when a sensor located in a zone
immediately downstream of a group of zones is
released, all zones in that group of zones are
actuated or made live.
Operation of the accumulator conveyor 18
will now be described with particular reference to
Figs. 2 through 13. Referring first to Fig. 2, the
first article L travels along the conveyor 18 in the
director of the arrow until it reaches the
mechanical stop 46, as shown in Fig. 3. When that
stop 46 is in place and the discharge valve 34 is in
the position shown in Figs. 2 and 3, actuator~ 30D,
30Dl and 30D2 are depressurized, and the friction
wheels 24D, 24Dl and 24D2 are lowered so that drive
rollers 20D in the discharge zone 37 are inactive.
When the first article L is in the
discharge zone 37, the sensor 38D is depressed, and
the valve 36D is in the Fig. 3 position so that the
drive rollers 20Zl are also inactive. However,
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drive rollers in zones upstream of the zone Zl
remain active so that the next article M can be
advanced as shown in Fig. 4 until the article M
reaches the zone Zl, as shown in Fig. S. When the
article M is in the zone Zl, the drive rollers 20Z2
in the zone Z2 are inactive so that when a next
article N reaches the zone Z2, the article N stops
in the zone Z2 as shown in Fig. 6. Additional
articles O and P stop in the zones Z3 and Z4,
respectively, as shown in Figs. 7 and 8.
When the article P has reached the æone Z4,
drive rollers of all of the zones of the Z group of
zones are deactivated, and in addition, the sensor
38E in the zone Z4 is depressed to connect the line
42Yl to a relief line 44A so that friction wheels
24Yl in the zone Yl, the downstream zone of the Y
group of zones, are lowered and drive rollers in the
zone Yl are deactivated. A next article Q therefore
stops in the zone Yl, as shown in Fig. 9 and
similarly additional articles, not shown, will stop
in zones further upstream.
When the mechanical stop 46 is raised and
the discharge valve 34 is moved to its other
position, as shown in Fig. 10, air under pressure
from the air line 32 passes through the valve 34 and
the line 28 to the actuators 30D, 30Dl and 30D2 to
raise the friction wheels 24D, 24Dl and 24D2 into
driving engagement with the drive rollers 20D of the
discharge zone 37 to advance the article L from the
discharge zone 37.
When the article L clears the sensor 38D of
the discharge zone 37, the valve 36D rises to its
Fig. 11 position, and air under pressure is directed
through the valve 36D and the line 42Zl to cause
raising of the friction wheels 24Zl of the zone Zl
and actuation of the drive rollers 20Zl of the zone
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Zl. Further, although the sensors 38B, 38A and 38C
in zones Zl, Z2 and Z3 remain lowered, they are
overridden by the secondary control circuits through
the valve 36D and lines 42Zl, 42Z2, 42Z3 and 42Z4,
which supply air to the actuators for zones Z2, Z3
; and Z4 to cause actuation of the drive rollers of
the zones Z2, Z3 and Z4 so that the articles M, N, O
and P start to advance as a group as the article L
exits from the accumulator conveyor 18.
When the article M reaches the sensor 38D
in the discharge zone 37, as shown in Fig. 12, the
valve 36D is again depressed, and the drive rollers
20Zl in the zone Zl are rendered inactive until the
article M has cleared the discharge zone 37.
However, the drive rollers in the zones Z2, Z3 and
Z4 remain active until the sensors 36B in zone Zl is
depressed by article N. The articles O and P
therefore continue to advance at the same speed as
article M, and if the article N should decelerate as
it coasts in zone Zl, the article O will tend to
move against it and move it forward at the same
speed until it depresses sensor 36B and thereby
causes deactuation of the drives in zones Z2, Z3 and
Z4.
As soon as the article M clears the sensor
38D, as shown in Fig. 13, the drive rollers in all
of the Z group of zones are reactuated, and the
articles N, O and P continue to advance as the
article M iS discharged. In addition, as soon as
the article P clears the sensor 38E of the zone Z4,
as shown in Fig. 12, the sensor 38E and the valve
36E rise to the Fig. 12 position so that the drive
rollers of the Y group of zones (zones Yl, Y2, Y3
and Y4) are actuated, and articles in the Y group of
zones are advanced in the manner illustrated by the
article Q and R are shown in Fig. 13.
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When articles in the zone Y4 (Fig. lA)
clear the sensor 38G in the zone Y4, drive rollers
of an X group of zones (only one of which is shown)
are similarly actuated. Thus when the first article
is released and advances from the accumulator
conveyor 18, the remaining accumulated articles are
discharged in groups without requiring a wait until
there is a vacant zone downstream any of a
particular zone before an article can exit that
zone, except that a space approximately equal to a
zone is maintained between successive group of
packages.
The accumulator conveyor illustrated in the
drawings and described above is subject to
structural modification without departing from the
spirit and scope of the appended claims.
What is claimed is:
A
