Communications: directive radio wave systems and devices (e.g. – Directive – Position indicating
Reexamination Certificate
2000-02-14
2001-11-13
Issing, Gregory C. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Position indicating
C235S385000, C340S870030, C700S116000, C700S215000
Reexamination Certificate
active
06317082
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates in general to material replenishment for product manufacture and/or assembly systems, and the like, and is particularly directed to a wireless (e.g., radio) call tag-based communication network that is readily installable in the (assembly line) infrastructure of a production facility, and which is operative to facilitate a (line-side) workstation user's requesting and obtaining delivery from (off-line) storage of one or more components used by that workstation in the course of its operation.
BACKGROUND OF THE INVENTION
Manufacturers of a wide variety of products currently employ a material resupply technique, commonly referred to as ‘pull manufacturing’, to replenish parts or materials required by an assembly line-side workstation in the course of its participation in the production of an item of manufacture. A reduced complexity illustration of such a conventional pull manufacturing scheme is diagrammatically illustrated in
FIG. 1
as comprising a plurality of line-side workstations, two of which are shown as workstations
1
and
2
, that are distributed along an assembly line served by a conveyor
3
. As an item
4
being assembled is conveyed along the assembly line, each workstation performs a respective subassembly operation that incorporates one or more parts or materials into the item. Thus, as shown at workstation
1
, a part
41
is installed into the item; next, at a workstation
2
, downstream of workstation
1
, a part
4
2
is added to the partially assembled item, and so on down the assembly line.
In accordance with conventional ‘pull manufacturing’ material replenishment, the components at any given workstation, shown in
FIG. 1
as contained in local inventories of parts
4
1
and
4
2
, respectively associated with line side sites
1
and
2
, are updated in response to a request or ‘call’ from the workstation to a remote storage management and distribution subsystem. In response to the part request, the storage management and distribution subsystem then retrieves some number of the requested part from an off-line storage facility and delivers them to the requesting site.
In order for such an ‘optimal efficiency’ pull manufacturing replenishment scheme to be successful, it must be reliable, flexible and provide ‘on-time’ delivery. Unfortunately, within most of today's manufacturing environments, options for communicating material replenishment requests to those responsible for delivering the parts to a line-side workstation are considerably limited. A significant number of production facilities continue to employ traditional manual, labor-intensive routines, such as card-based methods. Others, which have attempted to incorporate upgraded communication methods, use hardwired subsystems, that are not only costly to install but, due to their inherent inflexibility, are expensive, time consuming, and labor intensive to retrofit or modify, as the needs and/or retooling of the plant are continually being updated and reconfigured. Although some wireless call systems have been proposed, they are complex, requiring two-way communications with a line-side location, and are thus extremely expensive to install and operate.
SUMMARY OF THE INVENTION
Pursuant to the present invention, the above-described shortcomings of conventional material replenishment systems are effectively obviated by a wireless ‘call tag’ based system, that is configured to take advantage of the communication and signal processing infrastructure of the tagged object radio location system of the type described in the U.S. Pat. No. 5,920,287, to D. Belcher et al, (hereinafter referred to as the '287 patent), the disclosure of which is incorporated herein.
In the tagged object radio location system described in the '287 patent, a plurality of transmission burst emission readers are distributed throughout a facility (such as a manufacturing plant or warehouse), that contains the objects to be monitored. These readers are operative to detect spread spectrum signals (repetitively and randomly) emitted by radio transmitter circuits within tags affixed to the objects being tracked. Each spread spectrum RF burst transmitted by a tag is encoded with information, including the identification of the tag and other optional parameter data. As the burst emissions are detected by a respective reader they are coupled to an associated correlation-based RF signal processor, which determines which spread spectrum signal received by the reader is the first-to-arrive signal from a tag. A tag-location processor then processes first-to-arrive signals from at least three tag transmission readers in accordance with a multilateration algorithm, and computes the location of the tag.
The present invention makes use of the spatially distributed reader and associated signal processor infrastructure of the tag-based system described in the '287 patent, by installing one or more ‘call tags’ at or in proximity of each workstation of a production assembly line where parts are replenished on an ‘as needed’ basis. Each call tag is associated with and is used to specify a particular component employed by its workstation; if a workstation makes use of different components, the workstation will be equipped with multiple call tags—one for each different component. As in the '287 patent, each call tag contains a transmitter that is operative to controllably transmit a spread spectrum RF signal containing encoded information including the identity of the call tag and other optional parameter information. When a component is to be replenished, a line-side workstation operator simply pushes a ‘call’ button on the tag.
In response to operation of the call button, the call tag's RF transmitter transmits or ‘blinks’ a spread spectrum RF signal burst encoded with the identification (e.g., serial number) of the tag. At the same time, an LED indicator is illuminated on the call tag to confirm to the operator that the ‘part call’ was transmitted. The RF burst emitted by the call tag is detected by at least one and typically a plurality of burst emission readers of a transmission burst monitoring and processing subsystem of the type described in the '287 patent, distributed within and/or around the workstation production environment of the manufacturing plant.
In the tag-based geolocation system of the '287 patent, first-to-arrive tag burst emissions detected by multiple (at least three) tag transmission readers are processed by a tag-location processor to compute the location of the tag. Such tag ‘location’ processing may also be carried out in the system of the invention, for example, to verify the location of the call tag, as specified in a resource management database. This geolocation feature can be especially useful in a changeable manufacturing environment, as it enables the replenishment scheme of the present invention to rapidly dynamically conform with whatever environment configuration variations may be made to the manufacturing plant (which can be expected to be subject to continual modification over time).
However, since the locations of lineside workstations where the tags are employed are normally known, a priori, tag geolocation processing is not necessarily required. Instead, the availability of multiple tag emission readers provides redundancy and thus a high degree of reliability in detecting and recovering the data encoded in a call tag's transmission burst. The fact that the transmission bursts are spread spectrum signals serves to make the transmissions effectively jam-resistant.
Irrespective of whether or not first-to-arrive signals from plural (at least three) readers are used to determine call tag location, the signal processing subsystem reads whatever identification and other data was conveyed in the call tag transmission burst. The call tag identification data is then used by a resource management operator to access a relational database, which stores information associating each call tag's identification data with a
Bacon Thomas M.
Hang Huong M.
Johnson Walter S.
Allen Dyer Doppelt Milbrath & Gilchrist, P.A.
Issing Gregory C.
Wherenet Corp
LandOfFree
Wireless call tag based material replenishment system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Wireless call tag based material replenishment system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wireless call tag based material replenishment system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2585530