Conveyors: power-driven – Conveyor section – Live roll
Reexamination Certificate
1999-01-15
2001-10-16
Ellis, Christopher P. (Department: 3651)
Conveyors: power-driven
Conveyor section
Live roll
C180S420000
Reexamination Certificate
active
06302266
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a zone control system for sensing and advancing articles in selected zones of a conveyor system and more particularly to an improved zone control module therefor.
BACKGROUND OF THE INVENTION
It is common practice to utilize conveyors for moving articles about a factory, warehouse or loading dock. Such conveyors generally include rollers, at least some of which are driven, to advance goods along respective conveyors. Prior conveyor systems have utilized air pressure to power actuators moving articles along conveyors. Some conveyor systems have optically sensed the position of articles from below conveyor rollers.
FIGS. 1-3
illustrate parts of a known conveyor system
10
of the type extensively used in factories, warehouses and the like to permit supporting and advancing of articles such as boxes thereon. The conveyor
10
includes power-driven article support elements such as rollers
12
which are disposed to define an elongate path, and the rollers are typically rotatably supported so as to extend transversely between a pair of elongate side rails, one such side rail
11
being illustrated in FIG.
1
. The conveyor
10
, when configured to function as an accumulating conveyor, typically has the rollers
12
defined into adjacent zones which can be independently driven from one another. For this purpose, the rollers
12
of each zone are typically independently driven from a main drive device such as a continuously driven line shaft
14
which extends lengthwise of the conveyor. The rollers
12
of the individual zones are then independently and selectively driven from the line shaft
14
through an intermediate drive transmitting device
17
which can be selectively actuated. This intermediate drive transmitting device, in the illustrated embodiment, includes an elongate twisted belt
16
which is engaged between the line shaft
14
and drive hubs associated with one or more of the rollers
12
defining the respective zone. The drive belt
16
in turn has an actuator
18
associated therewith for appropriately tensioning or de-tensioning the drive belt. The actuator
18
in the illustrated embodiment includes an extendable and contractible fluid pressure device such as an air cylinder, the latter causing appropriate extension or contraction of a wheel
19
which contacts the drive belt
16
and can be moved into or away from the drive belt to effectively tension or de-tension same. By tensioning the drive belt
16
, the frictional contact between the drive belt and the drive rollers
12
and line shaft
14
is sufficiently increased to effect driving rotation of the rollers
12
, whereas conversely when the belt is de-tensioned the drive belt slips relative to the line shaft so that the rollers of the respective zone are not driven.
The general arrangement of the conveyor as described above, when used as an accumulating and advancing conveyor, permits individual articles to be supported on and advanced from zone to zone without permitting the articles to contact or stack against one another. This advancing of the articles from zone to zone is facilitated by a conveyor control system
21
which includes a series of zone control modules
22
, only one of which is shown in
FIGS. 1 and 2
, disposed serially along the conveyor for controlling the individual zones.
In the known control system
21
illustrated by
FIGS. 1 and 2
, the zone control module
22
includes an optical sensor
33
which is disposed so as to project a sensing path
34
transversely across the rollers of an adjacent downstream zone so as to sense the presence or absence of an article in the zone which is located downstream from the zone being controlled by the respective control module
22
. When the sensor
33
senses the absence of an article or box in the adjacent downstream zone, it transmits a signal to the controller
22
which in turn supplies pressure fluid to the air actuating device
18
associated with the adjacent upstream zone to activate the rollers
12
so that an article in the upstream zone is advanced into the adjacent downstream zone. Due to the presence of such control modules
22
being located in series and controlling the respective zones, articles can be sequentially advanced from zone to zone.
The control module
22
of the prior art, as shown by
FIGS. 1 and 2
, include an electrical unit
23
which plugs into an electrical solenoid unit
24
, and the latter is fixedly secured to and operates a shiftable valve which is positioned interiorly of a manifold/valve unit
25
. A cable
35
electrically connects the optical sensor to the electrical unit. The electrical control units
23
of serially adjacent modules
22
are in turn electrically interconnected by electrical conductors
37
which have plugs
36
at opposite ends for joining to connector parts
38
provided on opposite ends of the units
23
so as to electrically connect the adjacent control modules.
In similar fashion the valve/manifold unit
25
has a through flow passage
26
which terminates at connector hubs
27
, and the adjacent modules
22
are joined together in fluid communication by fluid supply lines
28
connected to the hubs
27
. The serially-connected fluid supply lines at a remote end are joined to an appropriate source of pressurized fluid, typically air. The unit
25
has a load port
29
which connects to a line
31
which in turn connects to the actuator device
18
.
The control module, as illustrated by
FIGS. 1 and 2
, is typically fixedly secured to an inner surface of the side rails
11
, such as by screws
32
extending therethrough and being secured directly into the housing of the valve/manifold unit
25
.
With the arrangement illustrated by
FIGS. 1 and 2
, when the sensor
33
senses the absence of an article in the adjacent downstream zone, then a signal is transmitted to the electrical unit
23
which in turn energizes the shiftable solenoid associated with the solenoid unit
24
, and this in turn activates the valve disposed interiorly of the valve/manifold unit
25
. The activation of the valve permits pressurized fluid (i.e. air) from the supply line to pass through the valve to the fluid actuator
18
so that the belt associated with the upstream zone is tensioned to effect driving of the rollers
12
of the upstream zone, thereby permitting any article in the upstream zone to be advanced forwardly along the conveyor for movement into the adjacent downstream zone.
While the system described above relative to
FIGS. 1-3
has generally operated in a satisfactory manner, nevertheless the construction thereof has possessed disadvantages. The construction of the module and the interrelationship between the units and the mounting thereof on the frame rail of the conveyor have made it difficult to service and maintain the arrangement. For example, if the valve/manifold unit requires repair or replacement, then the entire module must be removed to permit such repair, and then remounted on the side rail. Further, access to the solenoid unit is also difficult because of the overall constructional and positional restraints on the system, and thus any replacement or servicing thereof substantially requires removal of the entire module.
With the conveyor control arrangement of
FIGS. 1-3
, it is occasionally necessary or desirable to simultaneously activate a series of zones so as to permit simultaneous advancing of all objects or articles therein, this being referred to as “slug” advancing movement. To permit the simultaneous movement of a “slug” or series of articles, the control system of
FIGS. 1 and 2
has the discharge port associated with each valve/manifold unit
25
connected to a discharge line. The discharge lines of the series of modules in turn connect to and discharge through a control valve which under normal conditions is maintained open to permit the normal discharge of air. This control valve is also connected to a slug line which in turn connects to a source of pressurized air. When slug movement is desired, the control valve is act
DeFrancisco Christopher J.
Fisher Mark T.
Ellis Christopher P.
Humphrey Products Company
Rader, Fishman, Grauer & McGarry, an Office of Rader, Fishman &
Sharma Rashmi
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