US3887284A

US3887284A - Scuffed container detector

Info

Publication number: US3887284A
Application number: US415615A
Authority: US
Inventors: James R Gender; Siamac Faani
Original assignee: Barry Wehmiller Co Inc
Current assignee: Barry Wehmiller Co Inc
Priority date: 1973-11-14
Filing date: 1973-11-14
Publication date: 1975-06-03
Anticipated expiration: 1992-06-03
Also published as: CA1032243A; DE2454041A1; GB1482796A; JPS5317516B2; JPS5081379A

Abstract

Apparatus for detecting scuff conditions in the wall of a transparent container in which the container is moved through an inspection station where a well defined narrow light beam is angularly projected onto the container in the area where scuffing generally occurs so that when the scuffing is objectionable, it produces a secondary light emitting area. Light sensing means is focused on the inspection station to respond to the secondary light emitting area when caused by an objectionable scuffed condition, the sensing means being located to one side of the axis of the light beam so it is not activated when the light beam passes through a container not scuffed or only lightly scuffed.

Description

United States Patent [191 Gender et al.

[58] Field Assignee:

Filed:

Appl.

SCUFFED CONTAINER DETECTOR Inventors: James R. Gender, Kirkwood; Siamac Faani, Ferguson, both of Mo.

Barry-Wehmiller Company, St. Louis, Mo.

Nov. 14, 1973 US. Cl 356/240; 209/] 11.7; 250/223 B Int. Cl G01n 21/16; GOln 21/32 of Search 356/237, 239, 240;

250/223 B; 350/175 TS, 205, 206; 209/11 1.7

References Cited UNITED STATES PATENTS June 3, 1975 3,736,065 5/1973 Cushing et al. 356/239 3,799,679 3/1974 Simko 356/237 Primary Examiner-Vincent P. McGraw Attorney, Agent, or FirmGravely, Lieder & Woodruff [57] ABSTRACT Apparatus for detecting scuff conditions in the wall of a transparent container in which the container is moved through an inspection station where a well defined narrow light beam is angularly projected onto the container in the area where scuffing generally occurs so that when the scuffing is objectionable, it produces a secondary light emitting area. Light sensing means is focused on the inspection station to respond to the secondary light emitting area when caused by an objectionable scuffed condition, the sensing means being located to one side of the axis of the light beam so it is not activated when the light beam passes through a container not scuffed or only lightly scuffed.

10 Claims, 6 Drawing Figures SCUFFED CONTAINER DETECTOR SUMMARY OF THE INVENTION This invention is directed to improvements in apparatus for detecting scuff conditions in reusable type transparent wall containers and embodies certain of the features heretofore disclosed in the Gender application, Ser. No. 322,485, filed Jan. 10, 1973 (now abandoned) and assigned to the assignee hereof.

Containers of the reusable types often are so roughly handled and knocked about in transit that the side walls become scuffed or scored to an extent that it not only detracts from the attractive appearance and may cause purchasers to believe that the contents is in some way defective but also the weakened containers due to scuffing may explode and shatter, thereby producing hazards to persons handling the containers. The shape of containers is normally such that repeated handling and processing activities cause the walls to rub against each other or against hard surfaces. The repeated rubbing destroys the normal slick surface finish and the surface becomes abraded and scuffed resulting in containers becoming brittle. If containers with objectionable wall scuff conditions can be detected and rejected in a rapidly moving line passing along a conveyor in a processing plant the danger of container explosion can be minimized and the plant can be operated more efficiently and economically since such containers can be eliminated before a product is placed therein.

Therefore, this invention is directed to providing a simple yet unique organization of components capable of detecting objectionably scuffed empty containers in a fast moving line and signalling rejection means to remove the objectionable containers from the line.

The preferred apparatus embodies means to accurately and selectively illuminate the transparent wall of each container as it moves through a directed light beam and to sense changes in the light quality so that when a scuff condition diffuses the light that change will produce a signal to operate a reject device for removing the offending container from the line. In achieving the result sought a well defined beam of light is directed at some desired angle to the normal vertically upright container wall. The angle of the light beam is such that it passes into the container and emerges from the opposite side in a location where scuffing normally is the greatest, the angle being selective depending on the shape of the containers being inspected. When the container wall is relatively unscuffed or has a good surface finish, the light beam passes through essentially undisturbed except for the shift in its axis due to refraction effect of the wall material. When, however, the light beam finds a scuffed wall in which the surface is abraded and irregular, the scuff condition produces a secondary light emitting area and diffuses the light in all directions and the result is that a bright area is raised on the wall, the brightness being a function of the degree of scuffing and abrading. The light diffusion is generally independent of whether the container is wet or dry and this is important for in many processing plants the containers first pass through washing equipment before moving through the detector apparatus of this invention.

The diffused light area of the container is sensed by light responsive means positioned out of the direct line of the light beam but in a position to view the area where diffused light will occur. The sensing means may be any of several photo-electric devices such as photocells, phototransistors, or photo-diodes which when activated by a predetermined light level will generate an electrical signal or pulse which is capable of operating a reject device. It is preferred to employ a photomultiplier tube device and focusing lenses and color filter means when other than clear wall containers are being inspected. A light limiting device, such as a Ronchi Ruling, is also employed to adjust the amount of light reaching the tube device such that the tube device operates on a desirable part of its electrical characteristic curve.

The principles of this invention are embodied in apparatus comprising means directing a well defined beam of light along a path to intercept the line of movement of a series of transparent wall containers and pass through the wall angularly so that scuff conditions can produce a secondary light emitting source of light, and light sensitive means suitably positioned to look at the container wall being illuminated and respond to the occurrence of diffused light having a level that is characteristic of objectionable scuffed conditions.

A preferred embodiment of the present invention may comprise means directing a narrow and well defined beam of light along an accurate path to intercept the container angularly and pass on through the container wall area normally subjected to scuffing, said light beam on passing through the container being primarily diffused by objectionable scuff conditions in the wall, a light sensitive unit spaced from the container on the side from which light is emitted, said unit being offset from the path followed by said light beam after passing through the container, whereby said unit is responsive to the level of primarily diffused light due to the objectionable scuff conditions.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is disclosed in connection with a presently preferred embodiment of apparatus shown in the accompanying drawings, wherein:

FIG. 1 is a generally schematic plan view of the several components of apparatus by which the principles of this improvement may be carried out in a commercial form;

FIG. 2 is a fragmentary sectional elevational view taken at line 2-2 in FIG. 1;

FIG. 2A is a detailed view of the means to provide a well defined light source to be projected through the containers in the inspection station;

FIG. 2B is a fragmentary view of a container showing the well defined light beam in relation to the scuff area on a container;

FIG. 3 is a fragmentary and diagrammatic view of certain components of the apparatus shown in FIGS. 1 and 2; and

FIG. 4 is an electrical circuit block diagram for the preferred apparatus of this disclosure.

DESCRIPTION OF THE APPARATUS In FIG. 1, the apparatus includes a suitable conveyor 10 for moving a series of transparent wall containers 1 1 into the several

peripheral recesses

12 and 13 of a pair of vertically spaced and

free wheeling starwheels

14 and 15 respectively. The

starwheels

14 and 15 are mounted on a vertical shaft 16 (FIG. 2) in which suitable means (not shown) is incorporated to control the application of suction to the several suction cup devices 17 which move in alignment with the

starwheel recesses

12 and 13. This apparatus has been more particularly shown and described in the prior patent of Wyman Pat. No. 3,160,277 and reference is made thereto for operating details which are merely adjunctive to this disclosure.

In this apparatus, the containers 11 are retained in the

starwheel recesses

12 and 13 by means of belt means 20 passing about

pulleys

21 and 22 during the transit through the inspection station and onto the carry-off portion A of the conveyor 10. Containers to be rejected are held tightly against the starwheel pockets by means of suction cups 17 sucking the bottles when activated by reject solenoid 18 and are carried through the inspection station onto the rotating collection table 19, whereby the suction is released by a mechanical reset device (not shown) which breaks the suction effect of cups 17. The bottles are then free to. be smoothly dropped on the rotating collection table 19.

The inspection of each container is signalled by the neck portion of a container breaking a beam of light directed from light source 23 onto a photocell 24 mounted on the structure of a suitable light shield 26 shown in FIG. 2. The inspection itself is carried out by means to be described. The uppermost starwheel 14 cooperates with the inspection means by being provided with elongated slots 27 so that as each slot registers with the inspection station, the light source shown generally by the housing 28 will be able to project its beam downwardly through the slot and angularly through the container 11 in the station. The light shield 26 keeps out ambient light and encloses light sensing means mounted in housing 25, the means in the housing being angularly off-set from the axis of the light beam projected by the light source 28. The sensing means is best seen in FIGS. 2 and 3.

The beam projected from the light source 28 is directed angularly downwardly through the starwheel slots 27, the angle A being in the range of 35 to the vertical axis of the container. The path of the light beam from source 28 follows the line XX in FIG. 3 so as to be aligned to one side of the window 29 in housing 25. The window is adapted to receive a light control device 30 which may be a Ronchi Ruling sheet. The interior of the housing is provided with a wall 31 in which a second window 32 is formed to receive (interchangeables) anyone of several color filter plates, one being seen at 33 suitable for the color of the containers being inspected. The window 32 is off-set from the axis X-X for the light source so that a photomultiplier tube 34 mounted in the housing space 35 has its viewing axis through the

windows

29 and 32 at an angle B of about 25 to the axis X-X. The angle B of the viewing axis may vary from to 40.

In FIG. 2 the light beam from source 28 is seen to pass through the near wall of the container and to emerge from the far wall in an area which is usually subjected to the greatest scuffing. As has been indicated, the angle of declination may be adjusted as needed to illuminate the container wall various distances above the bottom. The emerging light will, if the far wall is undesirably scuffed, create a secondary source of diffused light which is similar to the illumination of a frosted plate. Slight scuffing will not create the same amount of diffusion as a wall that is highly scuffed, and the photomultiplier tube 34 is sensitized to respond to the level of diffused light indicative of an undesired container. In FIG. 2A there can be seen the diagrammatic view of the light source 28 in which the elements are arranged for producing a highly accurate beam of light of a desired configuration. Due to the nature of scuffing on the containers, specially scuffing in the vicinity of the heel of the containers, the proper illumination of the scuffed area requires that the light spot reaching the scuff should be accurately controlled so that when the light rays refract through the bottle, the non-uniformity of the wall, heel, and the bottom of bottle will not affect the path of light rays, which otherwise can cause a good container to be falsely rejected.

In order to achieve the well defined beam of light, a commercial lamp 36 with very short filament is used as a primary light source. Two plano-

convex lenses

37 and 38 are used as a condenser combination to obtain a concentrated image F of the filament in lamp 36. The image F of the filament is utilized to illuminate an aperture 39 which can be accurately adjusted and controlled to have a small semi-circular, elliptical or rectangular configuration with sharp edges. The aperture is formed partly in a special plate 40 having a carefully ground area 41 to produce a knife-edge 41A for the aperture 39. The shape or size of the aperture may be varied by a slide 42 mounted on an adjusting screw 43 which is held by

nuts

44 and 45 in the desired position. The sharp edges prevent the distortion of light rays and this helps to produce a well controlled beam pattern. A collimator lens 46 is used to magnify the small sharp edged aperture size and transfer the aperture shape onto a first surface 47 of a mirror 48 which, in turn, reflects the shaped, collimated beam onto the scuffed area 49 (FIG. 28) on the bottle. The first surface 47 of mirror 48 is used to guarantee an undistorted beam pattern to be transferred to the scuff area 49. The mirror 48 is mounted on a precision gear mechanism 50 that enables the mirror to be angularly moved into the desired position for accurately locating the light spot on the scuffed area 49. The final image 39A of the aperture 39 on the scuffed area is shown as a semi-circle in FIG. 23.

It should be stressed that the image as seen in this view will emerge from the bottle essentially angularly undisturbed and with a predetermined shape and size, if there is no scuffing on the bottle. However, if scuffing exists to an objectionable level, the collimated beam with accurately controlled shape, size, and directed angle will produce a secondary source of light (FIG. 23) as it impinges on the scuffed area. The diffused light from the scuffed area will emanate in different directions, and the photo-sensitive element 34 suitably located in the vicinity of the container will detect the existence of light diffused from the scuff area. Since the beam is well defined, multiple reflections and refractions in good containers will be minimized, and will have little or no effect in producing false signals in the photo-sensitive element 34.

The apparatus above described includes a circuit for coordinating the timing photocell 24, the reject solenoid l8 and the photomultiplier tube 34. The circuit is shown diagrammatically in FIG. 4. A high voltage supply 52 and resistor network 53 are connected into the photomultiplier tube 34 to make it operative and to condition the electrical signal from the tube and make it useful for being amplified by a solid state amplifier 54. The signal from the amplifier is fed into a high gain differential comparator 55. An adjustable reference control 56 is connected to the differential comparator to compare the levels of incoming signals from the amplifier 54 with the desired reference level. The setting of the reference level control 56 can be adjusted to detect any grade of objectionable scuffed bottles. The timing photo-cell circuit 24 detects the arrival of each container 11 at the inspection station and generates an electrical signal which is sent through a Schmitt trigger 57 to the timing mono-stable multi-vibrator 58. The multi-vibrator 58 produces a timing pulse to control the length of time the container is being inspected. The timing pulse has constant magnitude and preset duration which activates the timing indicator network 59 to produce a visual indication that every container is being inspected. It also feeds into the mixer network 60, and together with the scuff signal coming from the differential comparator 55 produces a reject pulse which is fed to the reject monostable multi-vibrator 61. This latter multivibrator 61 produces another pulse of predetermined magnitude and duration which activates the reject indicator circuit 62 to give a visual indication of rejected bottle, it also activates a reject counter 63 which registers the number of containers being rejected, and finally it feeds the solenoid control circuit 64. The pulse from solenoid control circuit 64 activates the reject solenoid 18 (FIG. 2) which enables the sucker cup 17 to hold the rejected container until it is released onto the collection table 19.

The foregoing description has set forth a presently preferred embodiment of the apparatus for detecting the objectionable grades of scuff conditions in transparent containers. It is believed the principles of the invention can be clearly understood therefrom and that there is provided a simple and effective means to detect containers which have been scuffed to a degree sufficient to produce hazards due to eventual explosion and shattering of the containers, as well as seriously affecting the appearance of the containers and their contents.

What is claimed is:

1. Apparatus for detecting objectionable scuff conditions on the wall of transparent containers, which apparatus comprises: means supporting containers in an upright position and moving the same through a scuff detection station; a trigger device adjacent the detection station to generate a signal each time a container reaches the detection station; a source of light; a light control assembly between said source of light and the detection station, said light control assembly directing the light from said source as a single well defined beam into the detection station to penetrate the containers from one side and at an angle to the upright axis to illuminate the opposite wall in the zone where the scuff conditions occur, the scuffed condition of the illuminated container wall generating an area of diffused light which varies from container to container; a light sensitive member exposed to the illuminated container wall to generate a signal proportional to the level of light diffusion; control means connected to said light sensitive member to select a predetermined level of diffused light; and container reject means responsive to the signal from said trigger device and to said generated signal from said light sensitive member.

2. The apparatus of claim 1 wherein said light control assembly includes a beam shaping member having a sharp-edged aperture therein to receive and pass light from said light source, and means to vary the aperture opening.-

3. The apparatus of claim 2 wherein said apertured member is formed with an opening of a predetermined shape, and said varying means is movable relative to said apertured member to vary the size of said aperture.

4. The apparatus of claim 2 wherein said member having the aperture and said aperture varying means cooperate to shape the light beam as a semi-circle.

5. The apparatus of claim 1 wherein said light control assembly includes a beam shaping aperture, a first surface reflecting member disposed beyond said apertured member from said source of light, and means supporting said reflecting member for position adjustment to direct the reflected light beam toward the containers to be subject to detection of scuffing.

6. The apparatus of claim 5 wherein said light control assembly is spaced above the containers and directs the beam downwardly at an angle of from 15 to 35 off the upright axis of elongation of the containers and above the bottom of the containers' 7. The apparatus of claim 5 wherein said single light beam is angularly downwardly directed by said reflecting member onto and through the container from one side to emerge from the opposite side to originate the area of diffused light, said angular direction being selected to produce the area of diffused light for wet or dry containers.

8. The apparatus of claim 5 wherein the path of said light beam through the container is angularly downwardly to emerge adjacent the lower portion of the container where scuffing prevails, and said light sensitive member is horizontally spaced from the scuffed area and angularly set to one side of the path of said light beam.

9. The apparatus of claim 1 wherein said control means includes an electrical circuit having a comparator and a reference member connected to compare said generated signal with a predetermined light level from said reference member, said comparator producing a reject signal upon said generated signal and said reference light level being substantially equal, and means responsive to the production of a reject signal from said comparator to reject the container.

10. Apparatus for detecting objectionable scuff conditions in the wall of transparent containers comprising means to move containers single file through a detection station, a source of light above said station oriented to direct light angularly downwardly toward the containers, said projected light being in the form of a narrow and well defined beam to pass through the container and illuminate the area normally scuffed, a light sensitive member spaced horizontally from and positioned at the opposite side of the station from said projected light beam, said member responding to a predetermined level of light to generate a container reject signal, and means between the containers moved through the station and said light sensitive member to limit the field of view by said light sensitive member to the illuminated area of the containers where scuffing normally occurs, said light sensitive member generating a reject signal for any container having an objectionable scuffed condition causing a diffused light emitting area to generate a light brightness response equal at least to said predetermined level of light.

Claims

2. The apparatus of claim 1 wherein said light control assembly includes a beam shaping member having a sharp-edged aperture therein to receive and pass light from said light source, and means to vary the aperture opening.

6. The apparatus of claim 5 wherein said light control assembly is spaced above the containers and directs the beam downwardly at an angle of from 15* to 35* off the upright axis of elongation of the containers and above the bottom of the containers.

7. The apparatus of claim 5 wherein said single light beam is angularly downwardly directed By said reflecting member onto and through the container from one side to emerge from the opposite side to originate the area of diffused light, said angular direction being selected to produce the area of diffused light for wet or dry containers.