EP0086059A2 - Improvements in or relating to computers for use in sampling procedures - Google Patents
Improvements in or relating to computers for use in sampling procedures Download PDFInfo
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- EP0086059A2 EP0086059A2 EP83300400A EP83300400A EP0086059A2 EP 0086059 A2 EP0086059 A2 EP 0086059A2 EP 83300400 A EP83300400 A EP 83300400A EP 83300400 A EP83300400 A EP 83300400A EP 0086059 A2 EP0086059 A2 EP 0086059A2
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- sample
- rejection
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- G—PHYSICS
- G07—CHECKING-DEVICES
- G07C—TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
- G07C3/00—Registering or indicating the condition or the working of machines or other apparatus, other than vehicles
- G07C3/14—Quality control systems
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- G—PHYSICS
- G07—CHECKING-DEVICES
- G07C—TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
- G07C15/00—Generating random numbers; Lottery apparatus
- G07C15/006—Generating random numbers; Lottery apparatus electronically
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Abstract
A computer is disclosed for use in sampling procedures for testing samples of a batch of articles comprising a memory into which is entered one or more tables of data identifying a sample code by batch size and inspection level. Also entered in the memory is a file table of data representing a sampling plan identifying sample size and acceptance and rejection parameters by the sample code and an acceptable quality level. The sample code is identified by means for entering data representing the batch size and a predetermined inspection level. Means is provided for entering data representing a predetermined acceptable quality level and for utilising the identified sample code to identify the corresponding sample size and acceptance and rejection parameters. A visual display responds to the identified sample size to display this sample size. Means is provided which responds to the identified acceptance and rejection parameters to derive and store a value having a magnitude which is a function of such parameters. Means is provided for entering into the computer sample data representing the acceptance and rejection of each sample article tested and comparison means is provided to compare the entered sample data with the derived and stored value to provide a first signal representing batch acceptance or a second signal representing batch rejection.
Description
- This invention relates to improvements in computers for use in sampling procedures.
- Sampling procedures are known in which a given number of samples of a batch of products is tested to determine the extent of any defective attributes the samples may possess and the result of such a test is used as a measure of whether or not the batch is acceptable. Standards have been worked out and tables compiled for this purpose in which the accept/reject conditions are statistically based upon expansion of the Binomial and Poisson probability distributions. In most mass/batch production companies in the United Kingdom, goods that are received in bulk are inspected in accordance with the various charts and levels detailed in British Standard 6000, 6001 and 6002. However, as will be apparent hereafter, the complications of these charts are such that a considerable degree of training is required to understand the principles involved and inspection is generally held to the simplest plan available which is known as the "single sampling plan" although cost savings could be achieved using the more complicated plan known as the "sequential sampling plan".
- The tables and charts referred to, and in particular, B.S. 6001:72 will be well known to and understood by those skilled in the art. However, a brief description will be given for the better understanding of the invention.
- In sampling procedures it is necessary for the consumer or purchaser and the manufacturer to agree both the inspection level and the Acceptable Quality Level (AQL). BS 6001:72 provides for seven inspection levels of which four levels are special levels S-1; S-2; S-3 and S-4, used only for small sample sizes where relatively large risks can be taken and three general levels LI; LII and LIII of which LII is the most commonly used, level LI being specified where less discrimination is needed and level LIII being specified for greater discrimination. For a given batch size, the inspection level provides a code which defines the sample size to be inspected according to the sampling plan to be adopted.
- The AQL represents the minimum quality which can be accepted and may be expressed in per cent defective or in defects per hundred units for values of 10 or less but for values above 10 it must be expressed in terms of defects per hundred units. Inspection for per cent defective assumes that an article with one defect is to be rejected as much as an article with three defects and inspection for defects per hundred units assumes that an article with three defects is of as much concern as three articles with one defect.
- The sampling plans are arranged as columns of numbers, the columns being identified by the agreed AQL and the rows being identified from the code derived from the batch size and the inspection level. For a single sampling plan the columns comprise two sub-columns which identify the condition for acceptance or rejection of a batch.
- The single sampling plan requires all samples to be inspected and the numbers in the sub-columns of the AQL columns define the maximum number of defective articles which can be accepted and the minimum number of defective articles leading to rejection of the batch.
- For example for a batch size of 1201-3200 articles, the inspection level LII code is K. The normal single sample plan identifies this code as requiring a sample size of 125 articles and the AQL column for 1.0% gives the acceptance figure of 3 and the rejection figure of 4. All 125 articles in the sample have to be inspected and if 3 or less are rejected, the batch is considered acceptable and if 4 or more are rejected, the batch is rejected. In addition to the normal single sample plan, there are tightened single sample plans and reduced single sample plans. Generally, the normal plan is used but when two out of five consecutive batches have been rejected it is normally required to move to the tightened plan until five consecutive batches have proved acceptable when a return may be made to the normal plan. Reduced inspection may be instituted under certain conditions which include:
- a) 10 or more batches or a predetermined number of samples have been normally inspected and the total number of defectives is less than a given number defined on another chart;
- b) production is at a steady rate, and
- c) the responsible authority considers reduced inspection desirable.
- Thus in the above example code K for a tightened single sample plan still requires 125 samples but the figures for acceptance or rejection for an AQL of 1.0% are now 2 and 3. In the same example but for a reduced single sample plan the code K only requires 50 samples to be tested and the corresponding AQL numbers are 1 and 4 respectively. This means that if examination of the 50 samples reveals not more than 1 reject the batch is accepted and reduced inspection continues. If the number rejected in the sample is less than 4 but greater than 1 the batch is accepted but the normal sampling plan must be resumed. If the number rejected in the sample is 4 or more, the batch is rejected and the normal sampling plan must be resumed.
- In addition to the single sampling plan there are two other similar plans, each with its own normal, reduced and tightened versions. These are known as the "Double Sampling Plan" and the "Multiple Sampling Plan". Double sampling is a system in which a first sample is taken which is of a lesser number than it would be for a single sampling. If the quality is found to be sufficiently good, the batch may be accepted straight away and, if the quality is found to be sufficiently bad, the batch may be rejected. If, however, the quality is intermediate these two conditions, a second sample of the same size as the first must be taken and inspected before a decision is made, the number of defective articles in the first and second sample sizes being cumulative. Thus, in the above example, the code K gives a first sample size of 80 and a second sample size of 80 and the acceptance and rejection figures for an AQL of 1.0% are respectively 1 and 4 for the first sample and 4 and 5 for the cumulative first and second samples.
- The Multiple Sampling Plan is essentially the same as the Double Sampling Plan except that more than two samples may be called for. The plans generally provide for seven sampling stages all of equal size, although it is rare for a seventh stage to be required.
- The above described sampling plans require all samples in a sample size to be examined and each sample rejected counts as one, the rejections being cumulative.
- Another plan which is of importance is known as the "Sequential Sampling Plan" and operates on the basis of a starting handicap and a penalty number. In this plan account is taken also of acceptable articles and, for each acceptable article, 1 is added to the handicap number and, for each rejected article, the penalty number is subtracted from the running total of the handicap number. The batch is deemed acceptable when the running total of the handicap number reaches a value which is twice the initial handicap number and the batch is rejected if the running total reaches zero or less.
- The tables for the Sequential Sampling Plans differ from those of the Single Sampling Plans in that the AQL columns are single columns, i.e., there are no sub-columns representing acceptance and rejection numbers, and it is the rows which comprise two sub-rows, one sub-row representing the handicap (H) figure and the other sub-row representing the (b) penalty number.
- Referring once more to the above example, the table for Normal Sequential Sampling shows that the code K requires 224 articles in a sample. For an AQL of 1.0% the H figure is 54 and the b figure is 36. For each acceptable article in the
sample 1 is added to the handicap figure and for each rejected article in thesample 36 is subtracted from the running total. It will be seen that, if the batch is good, only 54 articles need be inspected to reach the acceptance figure of 2 x 54 =108 as compared with the normal Single Sampling Plan which requires 125. - There is also a tightened version of the Sequential Sampling Plan but there is no reduced version.
- It will be appreciated from the above discussion that considerable staff training is required to enable full use to be made of the sampling plans.
- It is an object of the present invention to provide a computer for use in sampling procedures which shall be capable of being produced in portable form and which shall be operable by relatively unskilled staff.
- According to the present invention there is provided a computer for use in sampling procedures for testing samples of a batch of articles comprising a memory into which is entered at least a first table of data identifying a sample code by batchsize and inspection level and a file comprising at least one sampling plan as a table of data identifying sample size and acceptance and rejection parameters by the sample code and an acceptable quality level (AQL), means for entering into the computer data representing the batch size and a predetermined inspection level to identify in the memory said sample code, means for entering into the computer data representing a predetermined AQL and for utilising the identified sample code to identify in the memory the corresponding sample size and acceptance and rejection parameters, a visual display responsive to the identified sample size to display said sample size, means responsive to the identified acceptance and rejection parameters to derive and store a value having a magnitude which is a function of said parameters, means for entering into the computer sample data representing the acceptance and rejection of each sample article tested, comparison means operable to compare said entered sample data with said value to derive a first signal representing batch acceptance or a second signal representing batch rejection.
- Embodiments of the invention will now be described by way of example, reference being made to the accompanying drawings in which:-
- FIG. 1 is a perspective view of a hand-held calculator- type computer embodying the present invention,
- FIG. 2 is a plan view of the lower part of the computer case shown in Fig. 1, the top part being removed,
- FIG. 3 is a plan view of the inside of the top part of the computer case,
- FIGS. 4A,4B,4C and 4D together represent a flow diagram illustrating one embodiment of the invention, and
- FIGS. 5A and 5B together represent a flow diagram illustrating another embodiment of the invention.
- The computer illustrated in Fig. 1 is similar in configuration to a hand-held calculator and comprises a substantially rectangular case indicated generally at 1 having an
upper part 2 and alower part 3 which can be secured together in any suitable manner. A number of function buttons or keys are mounted on theupper part 2 and comprise a "cancel entry"button 4, accept and reject buttons A5 and R6 respectively, tendigit buttons 7 representing thedigits 0 to 9, adecimal point button 7a, threebuttons buttons buttons upper case part 2 is a Texas TIL 398.3Type 8digit 7 segmentLED display module 18 which is viewed throughwindow 19. Thelower case part 3 houses a printedcircuit board 20 on which are mounted a Texas TMS 1000 Series Micro-Processor 21 and amemory microchip 22, connections being made between thecircuit board 20 and the function keys and theLED display module 18 by aribbon cable 23. A rechargeablebattery power pack 24 is connected to thecircuit board 20 and also to pins 25 opening to the exterior of the casing for recharging purposes. Anaudible alarm 26 incorporating an amplifier is also connected to thecircuit board 20 and thelower part 3 of the casing is vented as at 27 to allow the alarm to be heard. An on-off switch 28 is provided and may be located as required; in Fig. 3 it is shown mounted in thelower part 3 of the casing, and in Fig. 1 it is shown mounted in theupper part 2 of the casing. It could equally be provided as an on-off press button. - .The embodiment of the invention illustrated in Figs.4A,4B,4C and 4D is intended to provide for both Single and Sequential Sampling Plans including the normal, reduced and tightened versions of the Single Sampling Plan. Note that for convenience of illustration, Fig.4D is divided into two parts, Fig. 4D' and Fig.4D". The tables or charts representing these plans are stored in the
memory microchip 22. Each of the function buttons of the computer, when operated, generates its own unique code in binary or equivalent form, e.g., hexadecimal, and the computer is designed, by operation of these function buttons, to identify the selected table in the memory, to identify the code corresponding to the batch size and, by this code and the agreed AQL, to identify the appropriate acceptance and rejection numbers or the handicap and penalty numbers as the case may be. Operation of the rejection button R6 in the case of a Single Sampling Plan or operation of the acceptance.button A5 and the rejection button R6 in the case of a Sequential Sampling Plan then generate values which are automatically compared with the acceptance and rejection values of the plan to generate an alarm when the batch is to be rejected. - Referring to Figs.4A, 4B,4C and 4D, an operation is commenced by switching the computer on by means of switch27 (Fig.4A).The operator then operates the selected mode or plan button, let us assume the
Single Plan button 16, which then sends its code to acomparator unit 30 which compares the received code with stored codes and, if it identifies the code as acceptable, transmits the code at its Y (Yes) output or, if it is not acceptable, produces an N (No) output, the latter being used to operate thealarm 26 to indicate a malfunction. (All outputs referenced 100 are used to operate thealarm 26.) The coded Y output fromcomparator unit 30 is supplied to acomparator unit 31 arranged to identify the Single Plan code and to produce a Y output when it identifies that code or to pass the code to its N output when it fails to identify that code. In the latter case, the code is passed to the input of acomparator unit 32 arranged to produce a Y output if it identifies and accepts the code as representing a sequential sampling plan or an N output if it fails to do so in which case the N output actuates thealarm 26. However, assuming a Single Sampling Plan is selected, the Y output from comparator 31 (the Y31 output) opens agate 33 which is arranged to be supplied with the codes generated by operation of thebuttons - Whichever plan is selected (assume normal, i.e.,
button 11 is operated) the corresponding code is passed to acomparator unit 34 which produces an N output to operate thealarm 26 if the received code is not one of the three permissible codes or, if acceptable, passes the code to a string ofcomparator units comparator 35 identifies in thememory 22 the stored Single Sampling Plan (normal inspection) - say Table 1 -; the Y output fromcomparator 36 identifies in thememory 22 the Single Sampling Plan (tightened inspection) - say Table 2 - and the Y output from thecomparator 37 identifies the Single Sampling Plan (reduced inspection). An N output fromcomparator 37 indicates that the received code has not been accepted by any one of thecomparators alarm 26. At this stage, the computer has identified the table to be used in thememory 22. - The second stage (Fig.4B) is to identify the required column in that table by entering the agreed AQL. A Single Sampling Plan usually provides for 26 AQL values ranging from 0.010 to 1000 and an appropriate value must be entered to select the appropriate AQL column. This value is entered by the
digit keys 7 and is displayed by theLED display 18. If a mistake has been made and the AQL shown is wrong, it can be cancelled by operating the "cancel entry"button 4. However, assuming it to be correct, theAQL button 8 is operated to enter the number which is checked bycomparator unit 38 and, if acceptable, is passed to the string of 26 comparator units 39 to 3926 and, if one of these accepts the number it produces a Y output which identifies the column in the selected table. - The third stage (Fig.4C) is to identify the sample code from the batch size and the level selected from levels LI, LII and LIII.
- To this end, the
digit buttons 7 are operated to display the level required, e.g. 1, 2 or 3, in thedisplay 18 and thelevel button 9 is actuated to enter the displayed level. Actuation ofbutton 9 also instructs the computer that an operation is to be performed on the Level/Batch size table stored in thememory 22. This entered level is checked bycomparator unit 40, and passed to a string of threecomparators column digit keys 7, displayed ondisplay 18 and entered by operatingbatch button 10. This entered size is checked by comparator unit 45 (Fig.4D) to see if it is acceptable and, if so, is passed through the Y45 output to a string of fifteen comparators 461 to 4615 which by determining whether the batch size is below a predetermined value determine whether or not the batch size is within a given predetermined range. Thus comparator 46 determines whether the entered batch size is less than 8, comparator 468 whether it is less than 500, comparator 4614 whether it is less than 500,000 and comparator 4615 whether it is greater than 500,000. The comparator 46 which identifies the range of the batch size produces a Y outout which in turn identifies the line or row 47 to 4715 in the Level/Batch size table to identify the sample code. This sample code when applied to the selected table does two things, firstly it identifies in thememory 22 the sample size and, secondly, it identifies in thememory 22 the accept/reject numbers for a Single Sampling Plan or the handicap and penalty numbers for a Sequential Sampling Plan. These are read from the memory into atemporary store 48 which transmits the sample size to thedisplay 18 and which also transmits the accept/reject numbers or handicap/penalty numbers to aswitch 49 which hasinputs switch 49 routes the accept/reject numbers vialines comparator units comparator unit 55 and the rejection number intocomparator unit 56. - The operator now selects from the batch the displayed number of samples and commences testing. For each article of acceptable quality, the A5 button is operated and for each article to be rejected, the R6 button is operated. The operation of buttons A5 and R6 generates a corresponding coded signal which is supplied to switch 57 which is also controlled by the Y31 and Y32 outputs along
lines display 18 to deduct 1 from the displayed number. Assuming a Single Sampling Plan, the coded signals are routed alongline 58 to acomparator unit 59 operable to identify each "Accept" code which produces a Y output for each "Accept" code which is supplied to astore 60 and an N output for each "Reject" code which is identified incomparator unit 61 to produce a Y output which is supplied to thestore 60 and to thecomparator units store 60 is in effect a counter loaded or biased with the sample size number from thetemporary store 48 and counts the number of acceptances and rejections to produce an output alongline 62 when this count reaches the sample size number. - If before the count has been completed, the number of rejects equals the reject number, this is detected by the
comparator 56 to produce a Y output which is used to cause thedisplay unit 18 to display "FAIL" to show that the batch is not acceptable. If, however, the full sample size is tested without this occurring, the output from counter 60 alongline 62 is passed to gate 63 which is a gate normally held open by the N output from thecomparator 55 when the reject number is not greater than the acceptance number which has been supplied alongline 52. As the acceptance and rejection numbers only differ by 1 unit in the tightened and normal versions of the Single Sampling Plan, the display, for such a selection, will either show FAIL or PASS. However, for the reduced version of the Single Sample Plan, the difference between acceptance and rejection is greater than 1 unit and the corresponding numbers supplied alonglines comparators gate 64 which is only open when it receives a first input from the N56 output indicating that the number of rejects is less than the reject number and a second input fromline 62 indicating that the count is complete. Under such conditions the Y55 output is passed through thegate 64 to cause thedisplay 18 to display "PASS/F" to indicate that the batch can be accepted but that the normal version of the plan must be resumed. The PASS or FAIL display may be accompanied by an audible signal from thealarm 26 such as, for example, a continuous sound representing a PASS and an intermittent "bleep" representing a FAIL. - The description of Figs. 4A,4B,4C and 4D has so far largely been concerned with.the selection of a Single Sampling Plan. If a Sequential Sampling Plan is selected, the corresponding code is not accepted by the Comparator 31 (Fig.4A) which passes it through its N output to the
comparator 32 where it is accepted to generate a Y output which opensgate 73 which is arranged to be supplied with the codes generated by operation of thebuttons comparator unit 74 which produces an N output atline 100 if it does not identify one of the two acceptable codes or, if the code is acceptable, passes the code through its Y output tocomparator unit 75 intended to identify a normal plan and produce a corresponding Y output or pass the code through its N output to comparator 76 intended to identify selection of a tightened plan. The Y75 and Y76 outputs identify that a Sequential Sampling Plan has been selected and whether or not the normal or tightened version is required, thereby enabling the computer to identify the required table in itsmemory 22, - say tables 10 and 11, respectively. - The subsequent entry of the AQL (Fig.4B), the selected level (Fig.4C) and the batch size (Fig.4D) are as previously described with the result that the
display 18 displays the required sample size, and the temporary store receives this sample size and, in this case, the appropriate handicap and penalty numbers H and b. As in this case, theline 51 is energised from Y32, theswitch 49 supplies the H and b numbers alonglines store 79 and the H number being supplied to acounter 81 and also being doubled inmultiplier 80 and supplied as 2H tocomparator 82. The Y32 output alongline 51 operates theswitch 57 to send the signals from the A5 and R6 buttons alongline 82 tocomparator unit 83 intended to identify an acceptance and produce a corresponding Y output. If it is a rejection signal, thecomparator 83 passes the signal tocomparator unit 84 intended to identify a rejection signal and produce a corresponding Y output. Each Y83 output adds 1 to the number incounter 81 and each Y84 output causes thestore 79 to transmit the penalty number to thecounter 81 where it is subtracted from the running total. The running count incounter 81 is monitored by thecomparator 82 and afurther comparator 85 which is set to identify when the running count is less than 1, i.e., zero. Thecomparator 82 produces an output online 86 when the running count attains thevalue 2H causing thedisplay unit 18 to display PASS. Thecomparator 85 produces an output on line 87 when the running count falls below 1 or passes through zero to cause thedisplay unit 18 to display FAIL. - The embodiment described with reference to Figs. 4A,4B,4C and 4D may additionally incorporate the facility of using either one or both of the Double Sampling Plan and the Multiple Sampling Plan in any one or all of the versions reduced, normal and tightened. It will be described as incorporating both plans and all versions. To this end, the comparator 30 (Fig. 4A) would additionally store the codes representing the Double and Multiple Sampling Plans which would be selected by the
function buttons comparator string - Fig. 5A shows the arrangement for selecting the appropriate table for a Double or Multiple Sampling Plan from the
memory 22 and as it corresponds in substance to that described for the Single Sampling Plan, it need not be further described. Also, the entry of the AQL to identify the column in the selected table, the entry of the level and the batch size to identify the sample size code are all as previously described and are therefore omitted from this description. The derived sample code will identify in the selected table the sample size which, as has been mentioned, is of identical size for each of the two sample sizes which may be required for the Double Sampling Plan and is of identical size for each of the seven sample sizes which may be required for the Multiple Sampling Plan. This sample size is read into the temporary store 48 (Fig. 4D) and displayed in thedisplay 18. The derived sample code also identifies the accept/reject numbers for each sample size so that for the Double Sampling Plan there will be two pairs of accept/reject numbers and for the Multiple Sampling Plan there will be seven such pairs of accept/reject numbers. - The comparators D31 and M31 provide a Y output along
line 50, if selected, and this output operates theswitches switch 49 alonglines respective comparators gate 64 is supplied to aswitch 110 the output of which is normally supplied alongline 111 to thememory 22 or is switched along line 112 to thedisplay 18 to display PASS/F. In order to identify whether a Double Sampling Plan or a Multiple Sampling Plan has been selected and hence the possible number of sample sizes which may require to be tested, the comparator D31 (Fig. 5A) has a Y output along line D50 and the comparator M31 has a Y output along line M50 and these outputs are supplied to a counter 113 which is set by a D50 input to count two sample sizes and by the M50 output to count seven sample sizes and when such a count is completed, the counter 113 produces an output alongline 114 to operate theswitch 110 and pass the output fromgate 64 to thedisplay 18 to display PASS/F. - Assuming a Multiple Sampling Plan is selected, the
store 60 will be supplied from the memory with the sample size for the first testing and thecomparators display 18 to indicate PASS and, if the rejection number has been equalled or exceeded, the Y56 output will cause thedisplay 18 to indicate FAIL. If, however, the number is intermediate the acceptance and rejection numbers, there will be an output fromgate 64 and a second identical sample size will need to be tested. The output fromgate 64 will be supplied to the counter 113 and through theswitch 110 alongline 111 to thememory 22. This will cause thememory 22 to redisplay the sample size on thedisplay 18, to re-enter the sample size in thestore 60 and to supply the second pair of accept/reject numbers to thecomparators display 18 will either show PASS or FAIL or there will be an output fromgate 64 which passes throughswitch 110 and alongline 111 to thememory 22 to set up the apparatus for the next sample size test. In the event that thedisplay 18 does not previously show PASS or FAIL, the final sample size to be tested will be the seventh. For the normal and tightened versions of the Double and Multiple Sampling Plans, the accept/reject numbers for the final test differ by only one unit so that there can be no intermediate value to operategate 64 and thedisplay 18 will either show PASS or FAIL. However, for the reduced version, the accept/reject numbers for the final sample size differ by more than one unit and can produce an output atgate 64 if the actual number is intermediate the given values. In this case the output fromgate 64, in this case the seventh output, is recognised in the counter 113 which has been set up by the M50 input thereto, and this produces an output alongline 114 to operate theswitch 110 and direct the output fromgate 64 alongline 115 to thedisplay 18 to produce the display PASS/F. If a Double Sampling Plan is selected, it will be appreciated that there is only a first and a last sampling size, i.e., two sampling sizes of identical numbers of articles, to be tested and the operation is otherwise as described above, the counter 113 being set up by the D50 input to operate theswitch 110 at the end of the second sample size test. - The tables representing the sampling plans and their alternative versions may be considered as a file of plans stored in the
memory 22. For each such file plan, it is necessary to identify the sample code from a table which determines the sample code by the batch size and the inspection level which is predetermined. It will be appreciated that, if desired, the file may only contain one version of one plan so as to materially simplify the device and in any given application prevent an unskilled operator from having the opportunity of selecting an incorrect plan or the version thereof required. The file could, in fact, be in a separate memory capable of being plugged into the apparatus to provide the facility required for any given application. In this way, the apparatus could be issued to an employee set up for the purpose required and the employee would not have to make any selection of the plan or version required. - Where the apparatus holds less than the four plans and the versions thereof described, the number of function buttons can be reduced accordingly.
- It will be appreciated that the apparatus may hold any one or more of the plans described and the respective versions thereof.
- It will be further appreciated that the invention is not limited to the embodiments described by way of example and that various equivalents or modifications will be apparent to one skilled in the art and may be employed without departing from the scope of the invention. Such modifications and equivalents are to be considered to be within the scope of the invention disclosed in this specification.
Normal inspection is generally resumed if one of these conditions is breached.
Claims (11)
1. A computer for use in sampling procedures for testing samples of a batch of articles comprising a memory into which is entered at least a first table of data identifying a sample code by batch size and inspection level, and a file comprising at least one sampling plan as a table of data identifying sample size and acceptance and rejection parameters by the sample code and an acceptable quality level (AQL), means for entering into the computer data representing the batch size and a predetermined inspection level to identify in the memory said sample code, means for entering into the computer data representing a predetermined AQL and for utilising the identified sample code to identify in the memory the corresponding sample size and acceptance and rejection parameters, a visual display responsive to the identified sample size to display said sample size, means responsive to the identified acceptance and rejection parameters to derive and store a value having a magnitude which is a function of said parameters, means for entering into the computer sample data representing the acceptance and rejection of each sample article tested, comparison means operable to compare said entered sample data with said value to derive a first signal representing batch acceptance or a second signal representing batch rejection.
2. A computer according to Claim 1 in which the file table of data represents a single sampling plan in which the rejection parameters represent the minimum number of rejected articles in a sample size requiring batch rejection, the means responsive to said parameters is operable to derive said value as a function of said rejection parameters and said comparison means is operable to compare the entered sample data representing rejection with said value to generate said second signal representing batch rejection when said entered sample data representing rejection corresponds to said value and to generate said first signal representing batch acceptance when said entered sample data representing rejection has not attained said value and said entered data representing both sample acceptance and rejection identifies completion of testing of the full sample size.
3. A computer according to Claim 2 in which the file table includes at least the normal and tightened versions of the single sampling plan, and means is provided for entering into the computer a code identifying the version of the single sampling plan to be used.
4. A computer according to Claim 2 or 3 in which the file table includes the reduced version of the single sampling plan in which the acceptance parameters represent the maximum number of rejected articles allowable in a sample size to allow batch acceptance and continued use of the reduced version and any value intermediate said minimum and maximum values allows batch acceptance and denotes that use of the reduced version should be discontinued, said means responsive to the identified acceptance and rejection parameters being arranged to derive and store a first value which is a function of the acceptance parameters and a second value which is a function of the rejection parameters and said comparison means being operable to compare said entered sample data representing rejection of each rejected sample article tested with said first and second values to derive said second signal representing batch rejection in the event said entered sample data representing rejection attains said second value, said first signal at the end of the sample size test representing batch acceptance in the event said entered sample data representing rejection does not exceed said first value and a third signal at the end of the sample size test representing batch acceptance and discontinuance of the reduced version in the event said entered sample data representing rejection is intermediate said first and second values.
5. A computer according to Claim 1 in which the file comprises at least one sequential sampling plan table in which the acceptance and rejection parameters represent handicap and penalty numbers, the means responsive to the parameters is operable to derive and store a first value representing the penalty number, to derive and store a second value representing the handicap number, and to derive and store a third value which is a multiple of said handicap number; and said comparison means is operable to deduct said first value from said second value for each entry of sample data representing rejection of a sample, to add a predetermined value to said second value for each entry of said sample data representing acceptance of a sample to derive a running total and to compare said running total with said third value to generate said first signal representing batch acceptance when said running total attains said third value and said second signal when said running total falls below or attains a predetermined minimum value.
6. A computer according to Claim 1 in which the file table of data represents at least one sampling plan providing for the testing of at least two sample sizes of a batch in which the rejection parameters for each sample size represent the minimum number of rejected articles in the sample sizes tested requiring batch rejection, the acceptance parameters for each sample size represent the maximum number of rejected articles allowable in the sample sizes tested to allow batch acceptance and any value intermediate said minimum and maximum numbers for all but the last sample size to be tested denotes that a further sample size is to be tested, said means responsive to the identified acceptance and rejection parameters being arranged to derive and store, for each sample size, a first value which is a function of the acceptance parameters and a second value which is a function of the rejection parameters, said comparison means being operable to compare said entered sample data representing rejection of each rejected sample article tested with said first and second values to derive said second signal representing batch rejection in the event said entered sample data representing rejection attains said second value, said first signal at the end of each sample size test representing batch acceptance in the event said entered data representing rejection does not exceed said first value and a third signal at the end of each but the last sample size to be tested representing the requirement for testing a further sample size, said third signal being operable to identify the further acceptance and rejection parameters for such further test said means responsive to said identified acceptance and rejection values being operable to derive and store a third value which is a function of the further acceptance parameter and a fourth value which is a function of the rejection parameter.
7. A computer according to Claim 4 modified in that the file table represents a sampling plan allowing for the testing of at least two identical sample sizes in a batch in which at least all but the last sample size to be tested have acceptance and rejection parameters allowing for the entered sample data to be intermediate said first and second values for that sample size, characterised in that said third signal is operable to identify that a further sample size is to be tested and to identify the further acceptance and rejection parameters for such further sample, the means responsive to the identified acceptance and rejection parameters being arranged to derive and store values corresponding to such further acceptance and rejection parameters for the testing of a further sample size.
8. A computer according to Claim 7 in which the sampling plan is a double sampling plan allowing for the testing of up to two identical sample sizes in a batch.
9. A computer according to Claim 7 in which the sampling plan is a multiple sampling plan allowing for the testing of up to seven identical sample sizes in a batch.
10. A computer according to Claim 1 in which the file includes at least one version of at least one of a single sampling plan, a sequential sampling plan, a double sampling plan and a multiple sampling plan constructed and arranged to operate substantially as herein described.
11. A computer for use in sampling procedures having a memory in which is stored at least one version of a sampling plan and a table for identifying a sample code, means operable to enter the batch size to be tested and the inspection level required to identify in the table the sample code, means for entering an acceptable quality level, means responsive to the identified sample code and the entered acceptable quality level to identify the sample size to be tested and to identify acceptance and rejection parameters from the sampling plan, means for entering acceptance and rejection characteristics of samples tested in the identified sample size and means for comparing such entered characteristics with the identified acceptance and rejection parameters to provide a signal representing batch acceptance or rejection.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB08203001A GB2114329B (en) | 1982-02-02 | 1982-02-02 | Computers for use in sampling procedures |
GB8203001 | 1982-02-02 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0086059A2 true EP0086059A2 (en) | 1983-08-17 |
EP0086059A3 EP0086059A3 (en) | 1985-01-30 |
Family
ID=10528075
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP83300400A Withdrawn EP0086059A3 (en) | 1982-02-02 | 1983-01-26 | Improvements in or relating to computers for use in sampling procedures |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0086059A3 (en) |
JP (1) | JPS58176766A (en) |
AU (1) | AU1038983A (en) |
BR (1) | BR8300496A (en) |
GB (1) | GB2114329B (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0222935A1 (en) * | 1985-09-24 | 1987-05-27 | Roger Bennison | Random sampling system |
EP0261358A1 (en) * | 1986-08-23 | 1988-03-30 | Wilhelm Fette GmbH | Quality control method in the manufacture of tablets |
NL9002296A (en) * | 1990-10-22 | 1992-05-18 | Heijn Bv Albert | Self-service bar-code reader and totaliser - uses added customer identification card with reliability coding |
US5397882A (en) * | 1993-05-14 | 1995-03-14 | Ahold Retail Services Ag | Method for spot checking a client in a self-service store |
US5468942A (en) * | 1994-04-18 | 1995-11-21 | Ahold Retail Services Ag | Dispensing device for hand scanners accessible from two sides |
US5637846A (en) * | 1993-05-14 | 1997-06-10 | Ahold Retail Services Ag | Method and apparatus for electronic payment by a client in a self-service store |
DE19645654A1 (en) * | 1996-11-06 | 1998-05-07 | Peter Heinrich | Computer control of decentralised business activities |
EP3553612A1 (en) * | 2018-04-13 | 2019-10-16 | Johnson & Johnson Vision Care Inc. | Sample size determination in sampling systems |
US10579035B2 (en) | 2014-10-09 | 2020-03-03 | Tetra Laval Holdings & Finance S.A. | Quality monitoring in a packaging line |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB977121A (en) * | 1959-10-22 | 1964-12-02 | English Electric Co Ltd | Improvements in and relating to the statistical sampling of quality control data |
GB1086631A (en) * | 1964-05-01 | 1967-10-11 | Lucas Industries Ltd | Apparatus for use in testing batches of articles |
DE1260836B (en) * | 1968-02-08 | Siemens Aktiengesellschaft, 1000 Berlin und 8000 München, 8000 München | Circuit arrangement for the automatic evaluation of the different test results obtained during quality controls by random sample tests | |
DE2751505A1 (en) * | 1977-11-18 | 1979-05-23 | Hans Ing Grad Bluemke | Successive random sampling test appts. - has number disc mounted rotatably behind cover provided with viewing windows |
US4282580A (en) * | 1979-09-10 | 1981-08-04 | Mcguire Susan | Pocket calculator with grade averaging function |
-
1982
- 1982-02-02 GB GB08203001A patent/GB2114329B/en not_active Expired
-
1983
- 1983-01-14 AU AU10389/83A patent/AU1038983A/en not_active Abandoned
- 1983-01-26 EP EP83300400A patent/EP0086059A3/en not_active Withdrawn
- 1983-02-01 BR BR8300496A patent/BR8300496A/en unknown
- 1983-02-02 JP JP58014702A patent/JPS58176766A/en active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1260836B (en) * | 1968-02-08 | Siemens Aktiengesellschaft, 1000 Berlin und 8000 München, 8000 München | Circuit arrangement for the automatic evaluation of the different test results obtained during quality controls by random sample tests | |
GB977121A (en) * | 1959-10-22 | 1964-12-02 | English Electric Co Ltd | Improvements in and relating to the statistical sampling of quality control data |
GB1086631A (en) * | 1964-05-01 | 1967-10-11 | Lucas Industries Ltd | Apparatus for use in testing batches of articles |
DE2751505A1 (en) * | 1977-11-18 | 1979-05-23 | Hans Ing Grad Bluemke | Successive random sampling test appts. - has number disc mounted rotatably behind cover provided with viewing windows |
US4282580A (en) * | 1979-09-10 | 1981-08-04 | Mcguire Susan | Pocket calculator with grade averaging function |
Non-Patent Citations (2)
Title |
---|
ELEKTRONIK, vol. 59, no. 4, 18th February 1977, pages 16-18; K.E. HUHN: "Senkt die Pr}fkosten" * |
IBM TECHNICAL DISCLOSURE BULLETIN, vol. 14, no. 6, November 1971, pages 1840-1841, New York, US; C.R. MARTIN et al.: "Sampling plan and reporting system" * |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0222935A1 (en) * | 1985-09-24 | 1987-05-27 | Roger Bennison | Random sampling system |
EP0261358A1 (en) * | 1986-08-23 | 1988-03-30 | Wilhelm Fette GmbH | Quality control method in the manufacture of tablets |
NL9002296A (en) * | 1990-10-22 | 1992-05-18 | Heijn Bv Albert | Self-service bar-code reader and totaliser - uses added customer identification card with reliability coding |
US5397882A (en) * | 1993-05-14 | 1995-03-14 | Ahold Retail Services Ag | Method for spot checking a client in a self-service store |
US5637846A (en) * | 1993-05-14 | 1997-06-10 | Ahold Retail Services Ag | Method and apparatus for electronic payment by a client in a self-service store |
US5468942A (en) * | 1994-04-18 | 1995-11-21 | Ahold Retail Services Ag | Dispensing device for hand scanners accessible from two sides |
DE19645654A1 (en) * | 1996-11-06 | 1998-05-07 | Peter Heinrich | Computer control of decentralised business activities |
US10579035B2 (en) | 2014-10-09 | 2020-03-03 | Tetra Laval Holdings & Finance S.A. | Quality monitoring in a packaging line |
EP3553612A1 (en) * | 2018-04-13 | 2019-10-16 | Johnson & Johnson Vision Care Inc. | Sample size determination in sampling systems |
Also Published As
Publication number | Publication date |
---|---|
JPS58176766A (en) | 1983-10-17 |
AU1038983A (en) | 1983-08-11 |
GB2114329A (en) | 1983-08-17 |
EP0086059A3 (en) | 1985-01-30 |
BR8300496A (en) | 1983-11-01 |
GB2114329B (en) | 1985-10-30 |
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