Data processing: measuring – calibrating – or testing – Measurement system – Weight
Reexamination Certificate
2001-07-23
2003-04-22
Bui, Bryan (Department: 2863)
Data processing: measuring, calibrating, or testing
Measurement system
Weight
C702S173000, C702S101000, C177S119000, C177S145000
Reexamination Certificate
active
06553331
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a weight checking apparatus. More specifically, the present invention relates to a weight checking apparatus that calculates the weight of an item on a weighing conveyor by measuring the weight of the weighing conveyor.
2. Background Information
In a production line for food products, a weight checking apparatus for checking the weight of products and screening the products is often placed near the end of the production line. An example of a conventional weight checking apparatus is shown in
FIG. 9. A
weight checking apparatus
101
shown herein mainly includes a loading conveyor
102
, a weighing conveyor
103
, an allocating conveyor
104
, a weighing portion
105
, and a controller
109
.
The weighing portion
105
can measure the weight of the weighing conveyor
103
. Once products (hereinafter referred to as items) are conveyed to the weighing conveyor
103
from the loading conveyor
102
, the controller
109
obtains weight data from the weighing portion
105
while the item is still on the weighing conveyor
103
. Then, the controller
109
calculates the weight of the item. Thereafter, the controller
109
performs an allocating process at the allocating conveyor
104
to screen the item based on the calculated weight of the item. In the weight checking apparatus
101
, a loading sensor
106
is provided to detect an item that has been loaded onto the weighing conveyor
103
from the loading conveyor
102
, as the loading sensor
106
is utilized. The loading sensor
106
is a photoelectric sensor having a pair of projector and light receiver. As the item is loaded from the loading conveyor
102
to the weighing conveyor
103
, the loading sensor
106
sends to the controller
109
a signal that indicates that an item has been detected. Then, the controller
109
obtains the weight value of the item when the item is completely loaded on the weighing conveyor
103
and the weight of the weighing portion
105
has become stable. In this manner, the weight checking apparatus
101
obtains the weight values of items sequentially, and screens the items at the allocating conveyor
104
based on their weight values.
In a production line of food products, there are various apparatuses such as a weight checking apparatus, as well as operators who monitor the apparatuses and perform manual operations. Therefore, there is a possibility that an item from outside the production line is loaded on the weight checking apparatus due to a mistake by the operator. In that case, if the item is loaded onto the loading conveyor
102
, the item will be weighed at the weighing conveyor
103
and screened out at the allocating conveyor
104
. However, if the item is loaded directly onto the weighing conveyor
103
, since there is no signal from the loading sensor
106
to the controller
109
, the weighing is not performed. Accordingly, the screening is not performed at the allocating conveyor
104
. In other words, if the operator inadvertently loads an item from outside the production line onto the weighing conveyor
103
, the item may pass through the allocating conveyor
104
as a normal item, and be conveyed to a subsequent process. More specifically, since a weight checking apparatus is often provided at the end of the production line, if an abnormal item passes through the weighing detection apparatus without being screened out, the problem is likely to be a serious one.
In view of the above, there exists a need for a weight checking apparatus which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
SUMMARY OF THE INVENTION
An object of the present invention is to prevent problems that occur when an item that is not weighed properly passes through weight checking apparatus.
A weight checking apparatus of a first aspect of the present invention includes a weighing conveyor, a loading sensor, weight detection means, weight change monitoring means, weight calculation means, and a controller. The weighing conveyor conveys an item. The loading sensor detects a loading of the item on the weighing conveyor. The weight detection means detects the weight of the weighing conveyor. The weight change monitoring means monitors a change in the weight value detected by the weight detection means. The weight calculation means calculates the weight of the item based on the weight value detected by the weight detection means. The controller switches between a weighing conveyor weight change monitoring process performed by the weight change monitoring means and an item weight calculation process performed by the weight calculation means, based on a detection signal from the loading sensor. The weighing conveyor weight change monitoring process is a control in which the weight change monitoring means monitors the change in the weight value. The item weight calculation process is a control in which the weight calculation means calculates the weight of the item.
Once an item is loaded onto the weighing conveyor of the weight checking apparatus, the loading sensor detects the loading of the item, and sends a detection signal to the controller. The controller switches between the weighing conveyor weight change monitoring process and the item weight calculation process, based on the detection signal from the loading sensor. In other words, in this apparatus, the weighing conveyor weight change monitoring process is performed until the loading of the item onto the weighing conveyor is detected by the loading sensor. When the loading sensor detects the loading of the item onto the weighing conveyor, it is possible to switch to the item weight calculation process. Then, once a period of time necessary to calculate the weight of the item elapses after switching to the item weight calculation process, it is possible to switch back to the weighing conveyor weight change monitoring process.
In this manner, it is possible to perform the weighing conveyor weight change monitoring process, in which a change in the weight value of the weighing conveyor detected by weight detection means is monitored. While the item weight calculation process is performed based on the loading of a normal item onto the weighing conveyor, however, the change is not monitored. Therefore, it is possible to detect as an error a change in the weight value of the weighing conveyor caused by something other than a normal item. For instance, if an item from outside the production line is loaded onto the weighing conveyor due to a mistake of an operator, the change in the weight value of the weighing conveyor is detected during the weighing conveyor weight change monitoring process. Accordingly, an error process such as stopping the apparatus and issuing a warning can be conducted. Weight change monitoring means and weight calculation means can be either included in the controller, or provided separately from the controller.
The weight checking apparatus of a second aspect of the present invention is the weight checking apparatus of the first aspect, further including warning means. The warning means cautions an operator by displaying a screen or issuing a warning. The controller notifies of an abnormality through the warning means when the weighing conveyor weight change monitoring process shows a change in the weight value of the weighing conveyor that exceeds a predetermined range.
When the change in the weight of the weighing conveyor exceeds the predetermined range, the warning means notifies of the abnormality. This is because the warning would be constantly issued if the normal range is not determined, since the weight value usually changes constantly due to the vibration from driving of the weighing conveyor. The weight checking apparatus of a third aspect of the present invention is the weight checking apparatus of either of the previously mentioned aspects, wherein the controller stops the wei
Bui Bryan
Ishida Co. Ltd.
Shinjyu Global IP Counselors, LLP
Vo Hien
LandOfFree
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