Statistical weighing

In the retailing of articles it is necessary to ensure that packages containing a plurality of articles fall within predetermined weight ranges. The invention is particularly but not exclusively concerned with the packing of bacon but applies to other articles in which: (a) predetermined weight of an article i.e. a slice of bacon is variable. The packages aree weighed at a first weigh station to determine whether they fall within a predetermined weight range or whether they fall within predetermined limits either side of said predetermined weight range. If the latter the packages are then fed to a second weigh station at which they are again weighed and according to the weight ascertained there, an operator is given an indication usually by lights as to the exact number of make weight pieces both in number and size which have to be added or subtracted to the package in order that the package shall then fall accurately within the predetermined weight range. The second weigh station is desirably controlled by a computer which is supplied with basic information such as: (a) the stated package weight (b) the average number of articles per pack (c) the predetermined make weight ranges and other factors.

I claim:

1. An apparatus for packaging articles to provide a package of a predetermined weight range which comprises a first weigh station, means for feeding packages to said station to determine whether said packages are within the said predetermined range or whether within predetermined limits above or below the said predetermined range, a second weigh station, means for feeding the packages which are not within said predetermined weight range to the second weigh station and means operable at said second weigh station to indicate to an operator the steps to be taken to ensure that the packages fall within said predetermined weight range, said means operable at said second weigh station being controlled by a computer which is supplied with:

(a) a stated pack weight,

(b) the average slice count per pack,

(c) predetermined make weight (plus or minus) ranges and

(d) a (k) factor as herein defined.

2. An apparatus according to claim 1 wherein the means operable at said second weigh station is operative to indicate to an operator whether to add or subtract predetermined articles or portions thereof in order that said packages weigh within said predetermined weight range.

3. An apparatus according to claim 2 in which said means operable at said second weigh station include lights or other indicators indicating to the operator whether to add or subtract and in what amounts.

4. An apparatus according to claim 1 in which said computer determines the points (actual package weight) at which the make weight pieces are to be added or subtracted to make the package weigh to the declared target weight according to the (k) factor.

5. A method of packing bacon into packages of a predetermined given weight which comprises:

(1) determining the declared target weight

(2) determining an actual target weight being a weight higher than the declared target weight

(3) determining an average bacon slice weight

(4) determining the number and weight of given make weight pieces

(5) determining the (k) factor as herein defined

(6) determining the range of weights above and below the actual target weight which is acceptable for the predetermined package weight (accept band)

(7) and ascertaining the giveaway weight range being the difference between the mean value of the accept band and the declared target weight.

6. In a method of preparing packages falling within a predetermined weight range, said packages including a quantity of discrete articles of like composition, the steps comprising:

(a) providing a plurality of said packages, each package comprising the same quantity of discrete articles of approximately the same weight and size,

(b) weighing seriatim the packages at a first weigh station to determine whether said packages are within the said predetermined weight range,

(c) advancing weighed packages which fall within the predetermined weight range to another station for further packaging and advancing weighed packages which do not fall within the predetermined weight range to a second weigh station,

(d) weighing seriatim the second mentioned weighed packages which do not fall within the predetermined weight range at the second weigh station to ascertain the amount by which the weight of each said package falls short of, or exceeds, the predetermined weight range,

(e) calculating automatically the correction required to be made to each said package to bring said package within the predetermined weight range and

(f) based on such calculations, instructing automatically an operator either to add articles or portions thereof to the said package, or to remove articles or portions thereof from said package, thereby to bring the weight of the package within the predetermined weight range.

7. In a method of preparing packages falling within a predetermined weight range, said packages including a quantity of individually sliced articles of like composition, the steps comprising:

(a) providing a plurality of said packages, each package comprising the same quantity of sliced articles of approximately the same weight and size,

(b) weighing the packages at a first weigh station to select those packages which are not within said predetermined weight range,

(c) then advancing the packages which are not within the predetermined weight range to a second weigh station,

(d) weighing said packages at the second weigh station to ascertain the amount by which the weight of each package falls short of, or exceeds, the predetermined weight range,

(e) providing a quantity of make weight pieces of a range of weights less than the average weight of the sliced articles,

(f) providing a computer to calculate the correction required to be made to each package to bring each said package within the predetermined weight range,

(g) activating the computer to calculate the corrections and to provide instructions to an operator and

(h) based on such calculations, instructing an operator either to add make weight pieces to, or to remove sliced articles from, or to remove sliced articles from and then add make weight pieces to, the said package in order to bring the weight of the package within the predetermined weight range.

8. A method according to claim 7, wherein each package constitutes a shingle of sliced bacon and the make weight pieces constitute selected portions of a slice of bacon.

9. A method according to claim 7, further including the step of instructing the operator by visual indicating means whether to add make weight pieces to, or remove articles from, or remove articles from and add make weight pieces to, the said package.

10. A method according to claim 7, further including the step of feeding the following data to the computer:

(a) a desired weight for each package,

(b) a selected quantity of sliced articles per package,

(c) predetermined make weight ranges for the make weight pieces and

(d) a K factor determined according to the equation K=X/(Mean), where the term "Mean" indicates the average weight per article of the sliced articles in a package and X indicates the weight range of the sliced articles in a package above and below the Mean.