Seam inspection apparatus

An apparatus to permit inspection of an object. The apparatus has a track with which the object can move. There is a carriage to carry the object along with the track. A clamp holds the object as it moves. An inspection zone is positioned on the track. There is a brake to stop the object moving along with the track at the inspection zone and the object is rapidly rotated in the inspection zone so it may be inspected, for example, by camera.

FIELD OF THE INVENTION 
This invention relates to a machine to assist in the inspection of objects. 
DESCRIPTION OF THE PRIOR ART 
In mass production techniques it is desirable that the object produced be 
inspected as a last step in its production to determine that all the 
necessary steps have been carried out and carried out properly. This is 
particularly true in canning where the seams of the finished cans must be 
inspected to see that they are of the appropriate quality to ensure that 
the goods do not deteriorate in the can and remain free of bacteria. 
The earliest and most obvious method of inspecting cans is by simple visual 
inspection. However simple visual inspection represents a considerable 
slowdown in a modern production line, with consequent increase in cost of 
production, and such techniques have long been seen as a point where 
improvement is required. Equipment has been used that automatically 
inspects the can using scanning equipment. However the problem with the 
prior art equipment is that it is laborious in that it normally involves 
the complete rotation of the inspecting equipment to go round the seams at 
the top and bottom of the can to determine that they are complete. 
SUMMARY OF THE INVENTION 
The invention therefore seeks to make substantial improvements in the 
inspection of objects and finds particular application in the inspection 
of the seams in a canning line. The present equipment provides substantial 
improvements in speed over the prior art equipment. 
Accordingly, the present invention provides an apparatus to permit 
inspection of an object, the apparatus comprising: 
a movable track with which the object can move; 
means to carry the object along with the track; 
clamping means to hold the object as it moves; 
means defining an inspection zone on the track; 
means to stop the object moving with the track at the inspection zone; and 
means to rotate the object in the inspection zone so it may be inspected.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The drawings show a machine useful in the inspection of cans and comprising 
a frame generally indicated 2 in FIG. 4 and with plate 4 bolted to it. The 
plate 4 has a housing 6 extending upwardly and braced by members 8 and a 
shaft 10 extends from the housing 6 to the top of the machine. The plate 4 
carries an electric motor 12 used to drive the machine. An output shaft 14 
of the electric motor 12 has a belt 16 driving a gearbox 18 through a 
pulley 20 on the input shaft 22 of the gearbox 18. The output shaft 24 
gearbox has a sprocket 26 mounted on it. The gearbox 18 is mounted on a 
plate 28 engaged on the shaft 10 by a bolt 30 and located in the frame 2 
at 31. 
The sprocket 26 drives a tubular member 32 mounted on the shaft 10 on 
bearings 34, the lower of which is protected by oil seal 35. The tubular 
member 32 is located in an outer sleeve 36 to which is attached a sprocket 
38. A cam plate 40 with cams 42 is located on flanges 44 on the member 32. 
A sprocket 39 is also attached to sleeve 36. Sprocket 39 drives chain 41 
to turn sprockets 43 (see FIGS. 1 and 4) and thus a shaft 45 outside frame 
2. Chain 41 passes through opening 47. 
A table 46 formed with openings 48 that define a track is formed at the top 
of the member 32. Bolts 50, such as shown in FIG. 4, ensure that the cam 
plate 40 rotates with the table 46. Slots 41' (FIG. 3) permit variation in 
the relative positions for plate 40 and table 46 for adjusting the timing 
between plate 40 and table 46. Spacers 51 are positioned around bolts 50 
to assist in locating table 46. Bolts 52 in the table 46 pivotally attach 
arms 54, as shown best in FIGS. 1 and 3. These arms 54 extend to a dog-leg 
56 attached to a roller 58 contacting a flange 60 on the shaft 10. As 
particularly shown in FIGS. 1 and 3 the flange 60 is formed with a 
flattened portion 62. The flange 60 is attached to the shaft 10 by bolt 
64. 
Rotation of the cam plate 40 acts to reciprocate a catch member 66. The 
catch member 66 is urged by spring 68 outwardly to the position shown in 
FIGS. 1 and 3. The spring 68 is in a housing 70 attached on a member 72 
extending from the frame 2 of the machine. The catch member 66 is provided 
with a primary lever 74 having a roller 76 that runs on the surface of the 
cam plate 40 but, upon contacting a cam 42 on the cam plate 40 the roller 
76 on the end of the lever 74 is forced outwardly to pivot the lever 74 
about pivot 77 thus retracting the catch member 66. 
The ends of the arms 54 remote from rollers 58 are provided with rollers 75 
extending downwardly into the track 48 formed in the table 46. There are 
channels 78 on each side of the track 48. 
A plurality of carriages 80 run with the track 48--see particularly FIG. 5. 
The relative positioning of each carriage 80 in track 48 may be varied 
slightly by movable, lockable stops 49 projecting from the end of each 
track 48. Arms 54 act to force the carriages 80 against stops 49 and 
screws 55 in arms 54 are to adjust the arms 54 to ensure they are tight 
against carriages 80 and there is no play between carriage 80, rollers 75 
and stops 49. Each carriage 80 comprises a chassis component 82 having an 
upper flange 84 and a lower flange 86 supported in bearing 87. The flanges 
84 and 86 are provided with threaded openings 88 to receive screws 90 
lockable by lock nuts 91. These screws 90 are used to level the chassis 82 
relative to the table 46 by contacting ball bearings 92 rollable in the 
channels 78. Ball bearings 92 permit easy movement of the carriages 80 
relative to the track 48 at an inspection zone. Each carriage 80 includes 
a base plate 94 to receive an object 96, shown in broken line in FIG. 4. 
Plate 94 is rotatable on bearings 98 relative to the chassis 82. An arm 
100 extends from the upper flange 84 through bushing 102--see FIG. 4. A 
shaft 104 extends vertically from the bushing 102 and is located in the 
bushing 102 by screw 106. A stabilizer 108, not essential, is also 
attached to the rod 104 at 110 and a clamping mechanism 112 is attached to 
the top of the shaft 104 by use of bolt 114 attaching arm 113. Plate 
member 85 is attached to the flange 84 by screws 89. Member 85 bridge the 
space to the carriage 80 from the feed conveyor for the objects 96. 
A shaft 116 is attached to the base plate 94 and extends downwardly through 
the chassis 82 and has attached a pulley 118, extending to contact bearing 
87, at the end remote from the base plate 94. Needle roller bearing 119 
facilitates rotation of shaft 116. 
The apparatus is provided with an inspection zone generally defined by that 
area of the machine between a pulley 120 driven by electric motor 122 (see 
FIG. 4) mounting a belt 124 also extending around idler pulley 126 (see 
FIG. 3) attached at 128. The driven belt 124 contacts the pulley 118 on 
shaft 116 as shown in FIG. 4 to rotate the base plate 94 and thus the can 
96 carried by it. 
The apparatus has clamping means in the form of a top piece 130 spaced from 
the carriage base plate 94. The clamping means includes springs 132 urging 
the top piece 130 downwardly along shaft 134. The carriage and the 
clamping means are shown in particular detail in FIG. 5. The top piece 130 
is able to move vertically relative to the arm 113. Shaft 134 is located 
in bearing 136 and is able to rotate relative to the top piece or arm 113. 
The bearing rests against flange 138. A clamping member 140 contacts the 
top of the can 96 and is urged downwardly as a result of its contact with 
the top piece 130 and the action of the springs 132. 
The clamping means includes means to raise the top piece 130 against the 
downward force of the springs 132. That comprises a primary lever 142 with 
a fulcrum 144 attached to the arm 113. At one end 146, the lever 142 is 
provided with a roller 148 and the other end is attached to the shaft 134. 
As shown in FIG. 5, but as also noted in FIG. 2, the machine is provided 
with an abutment surface 150 extending between support members 152 shown 
in FIG. 1 surface 150 is aligned with the rollers 148. 
In addition the base plate 94 has an indent 154 to receive raising members 
or lifters 156. Lifter 156 is useful in raising the can 96 to facilitate 
its removal from the track. A shaft 158 extends downwardly to end in a 
flange 159 and a spring 160 is attached between the flange 159 and the 
shaft 116 through which shaft 158 extends. As shown particularly in FIGS. 
3 and 5 the track 78 has an abutment 162 positioned beneath it so that 
although the spring 160 normally urges lifter 156 downwardly contact with 
the abutment 162 forces the shaft 158 upwardly to raise the can 96. 
As shown particularly in FIG. 1 the track has an inlet area 164 and an 
outlet area 166. There are guides 168 to direct the cans 96 onto and away 
from the carriage 80 running on the track 48. A conveyor 170 feeds cans 96 
to the track and the conveyor, adjacent the inlet 164, is provided with a 
screw conveyor 172 which acts to separate the cans 96 as shown in FIG. 1. 
Rotors 174 on shafts 45 act to move the cans through the inlet 164 and 
outlet 166. 
The inspection zone is provided with a camera 176 to scan the objects as 
they are rotated. The camera 176 may be attached to a computer or may 
simply show an image at a remote viewing station, for example by 
television. It is at a fixed distance from the point of the can 96 as each 
can is rotated and inspected. 
Rejection equipment comprises a computer 178 to receive a signal from 
camera 176. If that signal is that a can is defective, the computer 
operates cylinder 180 to move pusher 182 to reject the can. 
The illustrated machine functions as follows: 
Cans 96 are fed along the conveyor 170 and are separated by screw 172. At 
the appropriate point a rotating member 174 pushing the innermost can 96 
across member 85 onto carriage 80 on the track 48. The rotating member 174 
is timed in such a way that when it pushes a can 96 on the track the can 
is automatically fed onto a carriage 80. To ensure correspondence between 
the incoming can 96 and carriage 80, stops 49 are first adjusted and the 
position of screws 55 changed as needed. As a carriage 80 moves round with 
the track 48, approaching the inlet 164 the lifter 156 is down in the base 
plate 94 but the lever 142 is activated so that the clamping member 140 is 
raised. Thus when a can 96 is placed on the carriage 80 the lever 142 
shortly thereafter leaves surface 150 and the clamping member 140 moves 
downwardly under the influence of the springs 132 to locate the can 96 on 
the carriage 80. The carriage is moved round the track 48, carried on the 
ball bearings 92, and kept against stop 49 by the arms 54, that is 
rotating with the table 46, under, of course, the drive of the electric 
motor 12. Each can 96 continues with the track 48 until it approaches the 
stop 66. When the carriage 80 reaches the about 6 o'clock position in 
FIGS. 1 and 3 it will be noted that first inner roller 58 on arm 54 is 
aligned with the beginning of the flat portion 62 on flange 60. As the 
roller 58 meets the flat portion 62 the stop 66 contacts the carriage 80 
and stops it moving with the track 48, the ball bearings 92 facilitating 
this action. The arm 54 is able to pivot about 50 or 52 and moves along 
the flattened portion 62 without exerting a force on the carriage 80. At 
the same time pulley 118 contacts the belt 124 and the carriage 80 and can 
96 are rapidly rotated. As the can 96 is rotated it is scanned by camera 
176. 
The cam plate 40 is arranged so that as a roller 58 reaches the end of the 
flat portion 62 on flange 60 a cam 42 on the cam plate 40 acts to retract 
the stop 66 and the arm 54 moves the carriage 80 with can 96 along track 
48 against stop 49 where they continue to move with the track 48 and plate 
46. 
The cam 42 on cam plate 40 moves past the roller 58 on the lever and the 
stop 66 moves outwardly immediately to be able to stop the next carriage 
80. This procedure is then repeated, that is the subsequent can is 
inspected. The can 96 moves with the track 48 until shaft 158 contacts the 
abutment 162 and, more or less simultaneously, the roller 148 on lever 142 
contacts surface 150. As a result the can is raised slightly above the 
base plate and the clamping plate 140 is moved away from the top of can 
96. Rotor 174 then contacts the can, guides it against the guide 168 back 
onto the conveyor 170 across member 85. 
If a defective can is seen by camera 176 that can is rejected as described 
above. 
FIGS. 6 and 7 illustrate a detail of a variation of the apparatus 
illustrated in FIGS. 1 to 5. When the apparatus of FIGS. 1 to 5 is 
required to operate at extremely high speed the reciprocating action of 
the stop 66 can introduce noise and vibration. The embodiment of FIG. 6 
and FIG. 7 is to be installed on a machine that otherwise is precisely as 
illustrated in FIGS. 1 to 5. In the embodiment of FIGS. 6 and 7 chain 41, 
driven by sprocket 39 as shown in FIG. 4, drives a sprocket 190 mounted on 
a jack shaft 192 on plate 28. A second sprocket 194 on jack shaft 192 
drives chain 196 to rotate sprocket 198 mounted on shaft 200 also located 
on plate 28. At the top of shaft 200 is a brake member 202 having a recess 
204 as shown in FIG. 6. As shown in FIG. 7 pulley 118 is provided with a 
ball bearing 206 extending outwardly from the surface of pulley 118. It 
should be noted that cam plate 40 of the FIGS. 1 to 5 embodiment is not 
present and the necessary timing is provided by the selection of sprockets 
190, 194 and 198 so that sprocket 198 turns relative to sprocket 39 at a 
rate of 6 to 1 when 6 carriages 80 are on the machine. 
The embodiment of FIGS. 6 and 7 functions as follows: 
As a carriage 80 approaches the pulley 118 with ball bearing 206 the 
machine is timed so that ball bearing 206 abuts member 202 at the position 
shown in FIG. 6 where member 202 is rotating in the direction of arrow A. 
The machine is timed so that in the FIG. 6 position the arm 54 in contact 
with the partially illustrated carriage 80 is just at the start of flat 62 
on flange 60 on shaft 10. As shown in FIG. 6 at this point belt 124 
rotates the can by rotating pulley 118 precisely as described above for 
the embodiment of FIGS. 1 to 5. That action is completed and recess 204 in 
member 202 aligns with the bearing 206 so that the braking effect is 
stopped, that is there is no obstruction in front of the bearing 206, and 
thus attached carriage 80, and at that stage arm 54 is timed so that it 
has reached the end of flat 62 on flange 60 on shaft 10. 
Once released carriage 80 is moved by arm 54 against stop 49 at the end of 
its track 48 precisely as described for the previous embodiment. The 
procedure is then the same. 
The advantage of the FIGS. 6 and 7 embodiment is quietness and smoothness 
of operation. There is no reciprocation and the rotation of the member 202 
is absorbed by ball bearing 206. 
The apparatus of the present invention thus provides a continuous 
inspection device in which extremely rapid rates of inspection can be 
achieved, rates so rapid that the normal production line is not in any way 
slowed.