US 3456788 A
Description (OCR text may contain errors)
July 22, 1969 v, s p EIAL LIGHT TRANSPARENT CONTAINER INSPECTING APPARATUS Filed July 10, 1967 FIGJ.
mm 5 mm NSN m o B w M 3 gm G m .l v Cl MM W 3 u? w J a u m a 4 w 3 3,456,788 LIGHT TRANSPARENT CONTAINER INSPECTING APPARATUS Virgil Melvin Stapf, St. Louis, and Momir Babunovic,
Des Pere, Mo., assignors to Barry-Wehmiller Company, St. Louis, Mo., a corporation of Missouri Filed July 10, 1967, Ser. No. 652,215 Int. Cl. B07c /34; H01j 39/12; G06m 5/10 U.S. Cl. 209111.7 3 Claims ABSTRACT OF THE DISCLOSURE Inspecting apparatus for light transparent containers in which light intensity sensitive means is applied to the work of rapidly and continuously looking at successive containers to determine if any container should be rejected for any of a number of reasons, such as being excessively scuffed.
This invention relates to inspection apparatus for determining particular characteristics or conditions in respect of light transparent containers, and is more particularly concerned with improvements in apparatus for inspecting containers for such conditions as excessive scuffing of the exterior surfaces thereof.
A particularly troublesome condition with transparent containers, including those made of glass as well as plastic, is that after a period of usage and rough treatment in commercial handling, certain fairly well defined exterior surfaces become scuffed and abraded to such an extent that it detracts from the appeal that the container makes to the purchasing public and actually causes loss of sales. On the other hand, the public image developed by the manufacturers beverage products being dispensed in clean non-shabby looking containers induces a ready acceptance on the part of the purchaser, as opposed to the shabby, unattractive appearance of beverage products that are contained in scuffed and abraded containers. It has been shown that the clean looking containers that impart a certain degree of sparkle or freshness to the contents will sell much more readily than a container that is dull and does not present the contents in an inviting manner.
A particularly important object of the present invention is to provide relatively simple, trouble-free inspecting apparatus that is both useful and novel in connection with inspecting containers for surface scuff and abrasion characteristics.
It is also an important object of the present invention to provide a simple and economical electronic system for cooperation with photovoltaic cells so as to provide reliable means to be coupled with equally reliable and economical mechanical means for determining, wtih respect to transparent containers, acceptable from unacceptable scuff and abrasion surface conditions.
A further object of the present invention is to provide an inspecting apparatus that will respond to variations in intensity of light projected through the container and produce a voltage output which is directly proportional to the difference between the acceptable and unacceptable characteristics of the container.
Yet another object of the present invention is to provide inspecting apparatus in which light is projected at containers passing an inspection zone and means is positioned opposite the light source to respond to the difference in the intensity of the light passing through different portions or areas of each container so as to produce a change in voltage which may be suitably utilized for actuating other means to eliminate the unwanted container from those that are determined to be acceptable.
Sttes Patent 0 3,456,788 Patented July 22, 1969 Other objects and attendant advantages of the present invention will be set forth in the following disclosure of preferred embodiments of the inspecting apparatus, reference being made to the several views in the accompanying drawings, wherein:
FIG. 1 is a fragmentary and somewhat enlarged plan view of container inspecting apparatus incorporating the present invention;
FIG. 2 is a fragmentary and greatly enlarged sectional elevational view taken at line 22 in FIG. 1;
FIG. 3 is a fragmentary developed plan view of the rotor member shown in FIG. 2; and
FIG. 4 is a simplified and schematic layout of the electronic system herein preferred.
Referring now to FIGS. 1 and 2, it can be seen that a usual type of table top conveyor chain belt 10 is provided with the usual side guides 11 and 12 for conducting in single file order a series of containers C to be inspected for external surface scuffing and abrasion conditions. The inspecting apparatus is illustrated by a rotary starwheel 13 which is formed with suitable peripheral recesses 14 suited to fit the curvature of the containers C. The starwheel 13 revolves about the center axis A and is positioned in relation to the linear travel of the containers on the conveyor 10 to pick up successive containers and register the containers with the successive peripheral recesses 14. The rotary movement of the starwheel 13 is caused by the pressure of the incoming containers C and carries the containers toward the opposite side guide 11 of the conveyor 10. As rotation continues beyond the point of near approach of the containers to the side guide 11 the recess 14 will then release the containers so as to allow them to travel again in a linear direction.
When each successive container reaches the position of container C-l it is in the inspection zone where a suitable frame 16 supports a source of high intensity energy in the form of the light 17 and on the opposite side of the container C1 there is an inspection unit 18 that contains the inspection equipment presently to be described. The light source 17 discharges a beam of light through which each container must pass. If the container C1 is acceptable it will pass linearly along the conveyor 10, but if it is unacceptable because of a too badly scuffed and abraded exterior surface, the starwheel 13, working in conjunction with a suction cup device 19 (FIG. 2), will carry the container across a suitable sta tionary deadplate 20 and into a reject accumulator table 21 which rotates in a direction opposite to the direction of the starwheel 13. The device 19 is similar to one disclosed in United States Patent No. 2,800,226, issued July 23, 1957. Thus, a rejected container C-2 will be removed from the flow of acceptable containers. In order to control the inspecting apparatus there is provided adjacent the frame 16 a suitable switch 22 having its feeler arm 23 positioned to engage each container as it is brought into the inspection zone and each container actuates the switch 22 to its ON position to energize an amplifier, presently to be described, and the amplifier remains energized for a predetermined period of time. When this period of time has elapsed the amplifier for the unit 18 is shut off and remains so until the next succeeding container approaches the position of container C-l.
Looking at FIG. 1, it can be seen that approximately the center one-third of each container is lighted due to the fact that as that portion of the container indicated by the reference line G strikes the feeler arm 23 it actuates switch 22 to the ON position. The container moves on toward the right and when its portion indicated by reference line H reaches the location of the feeler arm 23 it will allow the arm to move to the OFF position. Between the portions G and H the container surface is convex and is able to effect movement of the arm 23 because the container is firmly seated in its recess 14. Thus, during the illumination of the central portion of each container C1 the inspecting or looking for undesired surface conditions takes place.
In FIG. 2 there is shown the rotary starwheel 13 in association with an auxiliary starwheel 13 separated from each other by means of the suction cup device 19 having a series of suction cups 19' corresponding with each of the peripheral recesses 14 (FIG. 1). The starwheels 13 and 13' support the body and neck portions respectively of the containers, and freewheel about the axis A on a suitable shaft 24. The container C-l is shown in the inspection station where the light source 17 produces a source of light on one side of the container -1. The light travels through the container toward inspection unit 18 where the usable portion of the light is confined by a narrow but elongated slot (FIGS. 2 and 3). The slot is formed in the unit 18 so as to restrict the light beam to a selected vertical portion of the container where the undesired surface defects usually occur. The height of the usable light beam B ineludes at least a portion of the container that is not subject to surface defects so that a valid comparison is obtained between good and bad surface conditions.
Within the unit 18 there is mounted an electric motor 26 connected to the hub 27 of an inverted cup shaped rotor 28 having a series of sequentially arranged and stepped apertures therein. The apertures are successively passed across the beam of light admitted by the slot 25, and within the rotary cylinder 28 there is positioned a photovoltaic, selenium type, photocell 38*. The photocell 30 is suitably supported from the base of the unit 18 and is electrically associated with a circuit which is responsive to the change in voltage output of the photocell 30.
As shown in FIG. 3, the rotor 28 when shown in developed view provides a consecutive series of apertures 31a, 31b, 31c, 31d and 31s. As indicated, the apertures do not have to be regularly arranged, but apertures 31b and 31d may, for example, be located in the broken outline positions. Each aperture of the sequence has the same physical size so that there will be substantially no diflerence in the amount of light that is admitted to strike the photocell 30. Each aperture sweeps across the vertical slot 25 at least once during the time the central portion G-H of each container is in front of the light source 17. More than one sweep can be obtained by properly speeding upthe rotation of rotor 28.
As the individual containers, such, for example as container C-l, proceeds from left to right under the feeler 23 of the switch 22, it will actuate switch, 22 and that, in turn, will activate the detection electronic system shown schematically in FIG. 4. Each container is inspected during the time that control switch 22 is activated, which is to say between the time the central portion of each container moves from the position denoted at G to the position where the portion H reaches the position first reached by the portion G. During the time involved in this container movement it is necessary that the rotary cylinder 28 in the inspection unit 18 revolve fast enough to permit at least one sweep of the consecutive apertures 31a through 31a over the vertical limits of the viewing slot 25. This is necessary in order to permit the photocell 30 to have a chance to respond to conditions over a representative area of the exterior of the container that is usually subject to scufiing.
As the cylinder 28 rotates the photocell 30 receives light successively from 5 different levels along the axis or ength of the container C-1, and if there is an insignificant change in the direct current voltage output the electric system interprets this result to accept the container as being satisfactory. Five apertures are shown, but less or more apertures may be provided. An acceptable container, therefore, develops a substantially unvarying or steady voltage response from the cell 30 during the inspection time. The inspection apparatus also takes care of the possibility that at least one of the successive apertures 31a through 312 would see the portion of the container with good light transmission characteristics and at least one of these apertures would see the portion of the container with poor light transmission characteristics. In this situation the photocell 30 undergoes a change in its voltage output. The change in voltage is transmitted to an amplifier device which amplifies this change in voltage and causes a relay to be actuated. The relay actuation is then transmitted through a suitable means (not shown) which applies vacuum to the associated vacuum cup 19' whereby the container to be rejected is retained in its recess on the starwheel 13 until it has reached the area over the reject accumulator table 21.
It is important to realize that the same photocell is used for all of the looks that are made through the successive apertures 31a through 31c, whereby it is always comparing its own voltage changes as it is exposed to a source of light whose changing condition is directly governed by acceptable or unacceptable condition of transparency (light transmittability) of the container. Thus the present improvement in the electronic system automatically eliminates many of the inherent problems usually encountered, such as changes between two different photocells due to changes in temperature, humidity, power line voltage variations and similar conditions.
Turning now to FIG. 4, the photocell 30 is schematically shown connected to a photovoltaic or photoconductive intermediate circuit 32, and this circuit is connected to an amplifier and relay 33, such for example, as Module TR 4 manufactured by Farmer Electrical Products Co., Inc. of Massachusetts. The amplifier and relay 33 is operatively connected to the single pole double throw limit switch 22 which is utilized to turn on and to reset the amplifier and relay 33, as well as to allow a a timer 34 to start uniformly each time the control switch 22 (FIG. 1) is rendered inactive when its control feeler 23 reaches the position on the container represented by the reference line H at the conclusion of each container inspection. Timer 34 controls the length of time that the solenoid 35 is actuated, this solenoid being associated with a valve in the vacuum line connected to the respective suction cups 19'. Thus, the movement of each container C1 through the inspection zone turns on the switch 22 at G and turns it off at H. The distance, as previously noted, between G and H may comprise approximately the center one-third of each container. During the time switch 22 is in the ON position the container C-1 is inspected or scanned for the particular defeet or objection that could cause it to be rejected.
If the container is rejected a reject signal will be picked up by the amplifier 33. The amplifier 33 energizes its relay which latches into a locked position and quickly charges up a capacitor in timer 34. When the container leaves the inspection zone the switch 22 turns to the OFF position. At this time the capacitor in timer 34 discharges and energizes a relay to operate the solenoid 35 which opens a valve (not shown) in the suction cup unit 19. The suction cup 19' holds the container in its recesses in starwheels 13 and 13 until it is over the reject table 21 where it is released by a suitable valve trip device. Simultaneously the relay in means 33 is deenergized and the amplifier is reset to repeat the foregoing cycle on the next container that is objectionable.
As is suggested in FIG. 2, any difference in the intensity of light in any of the apertures 31a to 31e will produce a change in voltage output of the cell 30 which is sensed by means 32. Any one of the apertures 31a to 31c may produce the highest voltage on the cell 30. This voltage reading is used as the reference voltage against which the readings from the remaining apertures is compared. Thus, it is important that at least one aperture must always be arranged to scan the light passing through a clear or acceptable portion of the container while other apertures are arranged to scan the areas that may be objectionable in order to produce the maximum voltage change response from cell 30. It is also important that a zone of the container Where scufiing normally occurs shall be scanned during the time interval the one-third central portion G-H of the container diameter passes the inspection zone. The fixed light slot 25 prevents any stray light from striking the cell 30 and this avoids false reactions in the electrical system of FIG. 4.
In the foregoing apparatus, the response by the cell 30 to each container takes into account its color condition so that a clear container will cause a higher level of voltage output than will a dark or more dense container. Thus, as containers change in color or density the cell 30 will sense the change in intensity of the light and merely vary its voltage output in proportion, but for a container that needs to be rejected the cell Will produce a significant change in voltage output within the level of output caused by the light transmissibility of the container then being inspected.
While a preferred embodiment of the present invention has been disclosed it is recognized that variant and equivalent means may be utilized to practice the principles hereof.
What is claimed is:
1. Container inspecting apparatus for selectively passing and diverting light transparent containers including:
(1) a source of light;
(2) a light receiving unit spaced from said source of light;
(3) conveyor means moving containers in succession through the space between said source of light and said light receiving unit;
(4) and means to receive containers diver-led by the inspection apparatus; said light receiving unit comprising,
(a) a container scanning rotor formed with a plurality of scanning apertures located at different heights along the axis of the containers,
(b) a light sensitive cell disposed adjacent the path of movement of said rotor scanning apertures to receive light directed through said apertures from the containers (1) said cell being responsive to the intensity of the light received through said scanning apertures to produce a voltage change proportional to the light intensity and indicative of the transparency condition of the containers, said voltage output being substantially uniform for containers to be passed and varying for containers to be rejected,
(c) and means responsive to said varying voltage output to divert containers to said receiving means.
2. The apparatus set forth in claim 1 wherein said scanning rotor is a cylindrical member having the scanning apertures in its peripheral Wall, and said light sensitive cell is disposed within said cylindrical member.
3. The apparatus set forth in claim 2 and including a housing enclosing said cylindrical member, said housing being formed with an aperture aligned With said light source and admitting a predetermined portion of the light While excluding other portions of the light from passing to said cell.
References Cited UNITED STATES PATENTS 4/1953 Stoate 209--111.7 5/1968 Mayeau 209-l11.7 X
US. Cl. X.R. 250223; 35 6240