Inspection apparatus for inspecting articles moving on a conveyor

The inspection apparatus comprises scanning means and processing means operative to produce a lean signal which indicates how much an article moving on a conveyor leans from the vertical. Comparing means is operative to compare the lean signal with a first preselected standard and a second preselected standard which is lower than the first preselected standard. If the first standard is exceeded, the article is rejected by first rejecting means and, if the second standard is exceeded the article may be rejected by second rejecting means downstream of the first after further information has been obtained about the article from inspection devices, or the second standard may be used to provide an indication of a trend towards leaning.

BACKGROUND OF THE INVENTION 
This invention is concerned with inspection apparatus for inspecting 
articles moving on a conveyor, the apparatus comprising scanning means 
operable to scan each article from two directions, which are substantially 
perpendicular to one another, as the article moves on the conveyor and to 
produce two output signals each of which is respectively proportional to 
the apparent amount by which the article leans from the vertical in the 
scanning direction, processing means operative to square the two output 
signals and to add the squares together thereby producing a lean signal 
indicating the true amount of lean from the vertical of the article, 
comparing means operative to compare the lean signal with a preselected 
standard and to provide a reject signal in the event that the lean signal 
exceeds the preselected standard, and rejecting means downstream of the 
scanning means operative on receipt of a reject signal from the comparing 
means to remove the article from the conveyor. 
Glass containers which have just been manufactured are conventionally 
placed on a conveyor which carries them to inspection apparatus which 
inspects the containers to determine whether they are fit for their 
intended purpose. Such inspection apparatus may comprise, for example, 
lean detecting means for detecting whether the containers lean from the 
vertical by more than an acceptable amount, optical means for examining 
the containers optically, means for checking the neck opening size, and 
means for checking the containers for leaks. Such lean detecting means 
conventionally comprises scanning means operable to scan each container 
from two directions which are mutually perpendicular to one another as the 
container moves on the conveyor. From the output signals of the scanning 
means, processing means calculates a signal indicating the lean of the 
container, comparing means compares this signal with a standard 
preselected to indicate the maximum acceptable amount of lean, and 
rejecting means removes the container from the conveyor before it reaches 
the remainder of the inspecting apparatus if the standard is exceeded. 
Such scanning means and associated equipment is described in U.S. Pat. No. 
3,754,123. The lean detecting means including the reject means is located 
upstream of the remainder of the inspecting apparatus so that the leaning 
containers cannot damage the remainder of the inspecting apparatus or jam 
it. The containers not rejected by the lean detecting means are brought to 
rest at various stations for inspection to take place. Second reject means 
is associated with the remainder of the inspecting apparatus and removes 
any containers which fail tests at the stations. 
Inspection apparatus as mentioned above may comprise reading means for 
reading markings on the container which indicate in which mould the 
container was made since the output from many moulds is normally fed to 
the same inspection apparatus. In this case, it is possible to detect when 
containers from a particular mould fail particular tests and to take 
remedial action by changing the mould or moulding conditions. However, it 
is not possible to detect whether containers rejected by the lean 
detecting means would have failed any of the remaining tests. Furthermore, 
since the reading means is normally associated with the optical means and, 
therefore, is located downstream of the lean detecting means, the moulds 
in which the containers rejected by the lean detecting means were made are 
not recorded. 
It is an object of the present invention to provide inspection apparatus in 
which increased information about leaning articles can be recorded. 
BRIEF SUMMARY OF THE INVENTION 
The invention provides inspection apparatus for inspecting articles moving 
on a conveyor, the apparatus comprising scanning means operable to scan 
each article from two directions, which are substantially perpendicular to 
one another, as the article moves on the conveyor and to produce two 
output signals each of which is respectively proportional to the apparent 
amount by which the article leans from the vertical in the scanning 
direction, processing means operative to square the two output signals and 
to add the squares together thereby producing a lean signal indicating the 
true amount of lean from the vertical of the article, comparing means 
operative to compare the lean signal with a preselected standard and to 
provide a reject signal in the event that the lean signal exceeds the 
preselected standard, and rejecting means downstream of the scanning means 
operative on receipt of a reject signal from the comparing means to remove 
the article from the conveyor, wherein the comparing means is operative, 
in addition to comparing the lean signal with the first-mentioned 
standard, to compare the lean signal with a second preselected standard, 
which is lower than the first preselected standard, and to provide an 
indicating signal in the event that the lean signal exceeds the second 
preselected standard. 
In inspection apparatus in accordance with the last preceding paragraph, 
there are two standards of lean and the number of articles failing to pass 
each standard can be recorded. This enables further information about 
leaning articles to be recorded. For example, the indicating signal can be 
used to give warning of a trend towards leaning before the leaning becomes 
so bad that articles have to be rejected so that timely remedial action 
can be taken. Alternately, if the first standard is selected to indicate 
the maximum amount of lean which is permissible if damage or jamming is to 
be avoided and the second standard is selected to indicate the maximum 
amount of lean which is permissible if the articles are to be fit for 
their intended purpose, information can be obtained about whether articles 
falling between the standards fail any of the other tests in the 
inspection apparatus. This is done by providing second rejecting means, 
located downstream of the first-mentioned rejecting means, operative on 
receipt of a reject signal to remove an article from the conveyor, the 
provision of an indicating signal by the comparing means being effective 
to cause a reject signal to be received by the second rejecting means. 
Thus information can be obtained from inspection stations located between 
the two rejecting means. If the inspection apparatus comprises reading 
means operative to read markings on the article indicating in which mould 
the article was made information can be obtained about from which mould 
articles falling between the standards come. 
Where two rejecting means are used, if the comparing means is also 
operative to compare the lean signal with a third preselected standard, 
which is lower than the second preselected standard, and to provide an 
indicating signal in the event that the third preselected standard is 
exceeded, this signal can be used as a warning that the articles are 
developing a lean and remedial action can be taken. 
Advantageously, recording means records, for each article which exceeds a 
standard, in which mould the article was made so that manufacturing faults 
can be traced to a particular mould.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION 
The illustrative inspection apparatus is for inspecting articles, 
specifically glass containers C, moving on a conveyor 10. The conveyor 10 
comprises a conveyor belt 12 which moves the containers C to a supporting 
surface 14 along which the containers C are moved by carriages 16 of the 
conveyor 10 which move around a path beside the supporting surface 14. 
From the supporting surface 14, the containers C pass to a further 
conveyor belt 17 of the conveyor 10. The carriages 16 collect the 
containers C from the conveyor belt 12 and slide them along the surface 14 
to four inspection stations 18 at each of which each container is brought 
temporarily to rest for inspection. The conveyor 10 also comprises two 
spacers 20 which operate to space the containers C one from another. 
The illustrative inspection apparatus comprises scanning means 22 located 
downstream of the first spacer 20 and operative to scan each container C 
from two directions which are substantially perpendicular to one another 
at 45.degree. and 135.degree. to the direction of motion of the containers 
C. The scanning means 22 scans the containers C as they move on the 
conveyor belt 12. The scanning means 22 comprises two light-beam emitters 
24 and two light-beam receivers 26 arranged to receive beams from the 
emitters 24. The scanning means 22 produces two output signals on lines 
28. The output signals are each respectively proportional to the apparent 
amount by which the container C being scanned leans from the vertical in 
the scanning direction between the emitter 24 and the receiver 26. A 
fuller explanation of the principle of operation and the construction of 
the scanning means 22 is contained in the aforementioned U.K. Patent 
Specification No. 1383962. 
The illustrative inspection apparatus also comprises processing means 30 
which is also fully described in U.K. Patent Specification No. 1383962. 
The processing means 30 receives the signals on the lines 28 from the 
scanning means 22 and is operative to square the two output signals and to 
add the squares together thereby producing a lean signal on a line 32 
indicating the true amount of lean from the vertical of the container C. 
The illustrative inspection apparatus also comprises comparing means 34 
operative to compare the lean signal with a first preselected standard 
supplied from a store 36, with a second preselected standard supplied from 
a store 38, and with a third preselected standard supplied from a store 
40. The first preselected standard is selected to indicate the maximum 
amount of lean which is permissible if damage to the inspection apparatus 
or jamming thereof is to be avoided. Accordingly, the first preselected 
standard is set equal to the square of the maximum permissible lean. The 
second preselected standard is selected to indicate the maximum amount of 
lean which is permissible if the container C is to be fit for its intended 
purpose. Accordingly, the second preselected standard is set equal to the 
square of the maximum permissible lean and is lower than the first 
preselected standard. The third preselected standard is lower than the 
second preselected standard. 
In the event that the lean signal exceeds the first preselected standard, 
the comparing means 34 sends a reject signal on a line 42 and a signal on 
a line 44 to a computer 46 of the illustrative inspection apparatus. The 
line 42 leads to first rejecting means 48 of the illustrative inspection 
apparatus. The rejecting means 48 is beside the conveyor belt 12 
downstream of the scanning means 48 and is operative on receipt of a 
reject signal on the line 42 to remove the container C from the conveyor 
belt 12 by extending a plunger across the conveyor belt 12 to deflect the 
container C into a cullet chute 50. 
The illustrative inspection apparatus also comprises inspection devices 52 
located at the inspection stations 18. These devices 52 are protected from 
damage and jamming due to excessively leaning containers C by the 
operation of the first rejecting means 48. The devices 52 are connected by 
lines 54 to the computer 46 and send it a signal whenever a container C 
fails the test applied by that device 52. The device 52 furthest 
downstream also incorporates reading means operative to read markings on 
the containers C which indicate in which mould a container was made and to 
signal the markings to the computer 46 on a line 56. U.K. Patent 
Specification No. 1580735 describes such reading means. 
If a container C has a lean which does not exceed the first preselected 
standard, it passes to the stations 18 for further inspection. However, 
the comparing means 34, as mentioned above, is also operative to compare 
the lean signal with the second preselected standard and, in the event 
that the lean signal exceeds the second preselected standard, to provide 
an indicating signal on a line 58 to the computer 46. 
The illustrative inspection apparatus also comprises second rejecting means 
60 located downstream of the inspection stations 18 and the first 
rejecting means 48. On receipt of a reject signal on a line 62 from the 
computer 46 which, after a suitable time interval, passes a reject signal 
to the line 62 when it receives an indicating signal on the line 58, the 
rejecting means 60 is operative to remove the container C from the 
conveyor 10. The rejecting means 60 does this by extending a plunger 
across the conveyor belt 17 to deflect the container C into a cullet chute 
64. The computer 46 also sends a reject signal to the second rejecting 
means 60 on the line 62 if a container C fails any of the tests applied by 
the devices 52. 
If the lean of a container C does not exceed the second standard, the 
container C is not rejected unless it fails any of the tests applied by 
the devices 52. However, if its lean exceeds the third preselected 
standard, the comparing means 34 sends an indicating signal on a line 66 
to the computer 46. 
The computer 46 correlates the information it receives on the lines 44, 54, 
58 and 66. As far as containers C whose lean exceeds the first preselected 
standard are concerned, the computer 46 can only record the number 
rejected for this reason. However, as far as the containers C whose lean 
exceeds the second but not the first preselected standard are concerned, 
the computer 46 can record the mould from which they come and also whether 
they fail any of the tests applied by the devices 52. As far as containers 
C whose lean exceeds the third preselected standard but not the first or 
the second preselected standard are concerned, the computer 46 produces a 
warning signal on a line 68 to a warning device 70 so that a warning of a 
tendency towards leaning is supplied. The warning signal includes 
identification of the mould from which the container C has come. The 
computer 46, thus, provides recording means operative to record each 
instance of the lean signal exceeding any of the first, second, or third 
standards and, for each article exceeding the second or the third 
preselected standard, to record in which mould it was made and which 
standard was exceeded. 
The computer 46 is connected to a store 72 in which the information 
recorded is stored. The store 72 is connected to a visual display unit 74 
and a print-out unit 76. 
The illustrative inspection apparatus records increased information about 
leaning containers C since information is recorded about containers which 
would be rejected in conventional apparatus without passing to the devices 
52 and, in particular, without the mould in which they were made being 
detected.