US3512005A - Fill checking apparatus - Google Patents

Description

May 12, 1970 J. A. BAWDUNIAK FILL CHECKING APPARATUS Filed Dec. 16, 1968 FIG. I

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United States Patent US. Cl. 250223 Claims ABSTRACT OF THE DISCLOSURE An apparatus is disclosed which prevents false indications of underfill of moving glass bottles by an underfill checking system using two light responsive devices. In such a system the upper device is actuated at a predetermined time after the neck of the bottle intercepts the upper light beam. This action conditions the second light responsive device into effectiveness. The second light responsive device is positioned below the upper one and is actuated when the product in the bottle fails to intercept the lower light beam. The period of time the lower light responsive device is eifective after being conditioned for operation to check underfill, is limited to a short period while the center portion of the bottle passes before the lower light beam. In this way false indication of underfill, caused by the lower light beam being transmitted through the leading wall of the bottle when that wall is in the path of the lower light beam, is avoided. Similarly, false indication of underfill, caused 'by the lower light beam being transmitted through the trailing wall of the bottle when that wall is in the path of the lower light beam, is avoided.

DESCRIPTION OF THE INVENTION This invention is concerned with an apparatus for checking glass bottles for underfill of product by the use of two light responsive devices as the bottles are moved on a conveyor belt past a checking station, the upper light responsive device being actuated when the neck of the bottle intercepts the light beam directed on it to condition the lower light responsive device to check for underfill. Underfill will cause the lower light beam directed on the lower light responsive device to reach such device, rather than be intercepted by the product in the bottle. When the lower light beam reaches the lower light responsive device, a relay is actuated to stop the conveyor.

In such an apparatus there is a tendency for it to treat fully filled bottles as underfilled bottles, and so cause false underfill indications, when the bottles being checked are small and the exterior diameter of the bottle necks is a substantial proportion of the outside horizontal dimension of the broad side of the bottle. his tendency is caused by the lens effect of the leading wall of the bottle when it is in the path of the lower light beam, and by the lens effect of the trailing wall of the bottle when it is in the path of the lower light beam. This lens effect can be particularly pronounced in glass bottles that have uneven wall thicknesses, that is, where the thickness of the leading wall of the bottle is considerably greater than the thickness of the trailing wall of the bottle, and vice versa. These irregularities in wall thickness are especially prevalent in small glass bottles.

In the apparatus disclosed, two timing devices are provided, so arranged and connected as to prevent such false indications of underfill. The first timing device introduces a time delay between the time the bottle neck intercepts the upper light beam and the time the lower light responsive device is made effective to check for underfill. The second timing device measures the period the lower light responsive device is effective to check underfill, and terminates such period well before the trailing wall of the bottle comes into the path of the lower light beam.

3,512,005 Patented May 12, 1970 The invention is illustrated in the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a container filling and checking system in which the invention is used;

FIG. 2 is a view of the checking station taken along the line 2-2 of -FIG. 1;

FIG. 3 is a schematic wiring diagram of the fill checking apparatus of this invention; and

FIG. 4 is a schematic diagram to show the timing periods involved in the fill checking apparatus of this invention.

Referring to FIG. 1, an endless belt conveyor 10, which is driven by motor 12, has an upper run 14 on which containers 16shown as small glass -bottlesare supported and transported from an infeed end of the conveyor at the left to one or more loading stations 18, only one of which, for simplicity, is shown. At each loading station 18 a predetermined amount of product-in this case a predetermined number of tablets 20is dropped through chute 22 into the open neck 24 of the container 16 under the chute. The motor 12 is normally running continuously so the conveyor 10 is normally operating continuously. A container 16 may be detained at the loading station 18 by suitable means, not shown, while an automatic tablet counting and discharging apparatus, not

shown, discharges the predetermined number of tablets down the chute 22 into the container at the loading sta tion 18.

Upon completion of the discharge of the tablets into the container at the loading station 18, the container detaining means is released so that the container 16 is then moved by the belt 14 of conveyor 10 away from the filling station 18 toward the checking station 26.

Mounted at one side of the conveyor 10 at the checking station 26 there is a light source 28 from which emanates a light beam 30 that is directed onto a light responsive device 32 mounted at the other side of the conveyor 10 at the checking station. These are positioned vertically above the conveyor belt 14 at such a distance that the light beam 30 is interrupted by the neck portion 24 of the container 16 while the container is at the checking station 26.

Similarly mounted at the checking station 26 is a second light responsive device 38, mounted substantially vertically below the upper, or neck, light responsive device 32. To operate it a second light source 34 is mounted substantially vertically below the upper, or neck, light source 28, the light beam 36 emanating from the lower light source 34 being directed onto the lower light responsive device 38.

The vertical positioning of lower light source 34 and lower light responsive device 38 is such that the lower beam of light 36 is interrupted when the container 16 has a full quota of product therein-such as the prescribed total number of tabletsbut is not interrupted when the container 16 has somewhat less than a full quota of product (i.e., tablets) therein. As the automatic tablet counting and discharging apparatus that discharges tablets down chute 22 generally counts and discharges tablets in multiples of a number of tablets, such as 10 or more, and as the usual malfunction of such apparatus is that one of the multiples fails to discharge, such a malfunction results in a sufiiciently incomplete fill of the container to cause no interruption of the beam 36 when the container is in the loading station 18.

The closer the lower light responsive device 38 and its associated light source 34, are positioned to the full-fill level of the product in the container, the more sensitive the fill checking apparatus will be to an underfill.

The upper, or neck, light responsive device 32 is arranged to actuate a neck responsive relay when the upper 3 light beam fails to strike it, i.e., when the neck of the both: interrupts the upper light beam 30. This action is indicated on the schematic wiring diagram, FIG. 3, by the legend Dark operate.

The lower, or fill checking light responsive device 38 is arranged to actuate an underfill responsive relay when the lower light beam 36 strikes it, i.e., when there is an underfill of the bottle so that the light beam passes all the way through the bottle. This action is indicated on the schematic wiring diagram, FIG. 3, by the legend Light operate.

This schematic wiring diagram is now described. The upper, or neck, light responsive device 32 is connected through an amplifier 40 to the actuating coil 42 of a neck responsive relay 43. This relay has two switch arms 44 and 47 that, in the lower, unenergized position of the relay, engage contacts 45 and 48, respectively, and, in the upper, energized position of the relay, engage contacts 46 and 49, respectively. Connected to the input circuit of the amplifier 40 there is a time delay device 50, consisting of a capacitor 51 and a resistor 52, preferably adjustable and preferably in parallel with the capacitor 51. The function of this time delay device is to introduce a predetermined time interval, designated for convenience as TA, between the instant the neck 24 of the bottle 16 interrupts the beam of light 30' to the upper light responsive device .32, and the instant the light responsive device 32 is thereafter able to pass enough current to the amplifier to cause the neck responsive relay 43 to operate and move its switch arms 44 and 47 to their upper positions.

During this time interval TA, the bottle 16 is being moved by the conveyor 10. This time interval TA is diagrammatically illustrated in FIG. 4, in which the bottle 16 is assumed to be moving to the left, and time is indicated as progressing from left to right.

The lower light responsive device 38 is connected through an amplifier 54 to the actuating coil 55 of underfill responsive relay 56. This relay has two switch arms 57 and that, in the lower, unenergized position of the relay, engage contacts 58 and 61, respectively, and, in the upper, energized position of the relay, engage contacts 59 and 62, respectively.

However, the connection between the lower light responsive device 38 and amplifier 59 includes switch arm 47 and contact 49 of neck responsive relay 43, previously described, and also includes switch arm 63 and contact 64 of a relay 66 in a timing unit 68. Hence the circuit from the light responsive device 38 to the amplifier 54 must be closed at switch arm 47 and its contact 49, and at switch arm 63 and its contact 64, before the light beam 36 which impinges on light responsive device 38 causes the actuating coil 55 of the relay 56 to operate and move its switch arms 57 and 60 to their upper positions.

The function of the timing unit 68 is to provide a predetermined time interval TB, commencing with the eX- piration of time interval TA, during which the lower light responsive device 38 is efiective to detect and respond to an underfill in the bottle 16 while it is at, and passing through, the checking station 26. This is diagrammatical- 1y illustrated in FIG. 4, the cross hatched area being indicative of the portion of the bottle movement past the lower light responsive device 38 that such device is effective to detect and respond to an underfill.

The timing unit 68 commences to time upon the actuation of neck responsive relay 43 and the consequent engagement of switch arm 44 with its contact 46. In the typical timing unit shown schematically in FIG. 3, this action completes a circuit from one side 69 of the power supply, through adjustable resistor 70 and capacitor 71, in series, to the other side 72'of the power supply.

The timing unit 68 includes a unijunction transistor 73 in which the emitter is connected to the junction point 74 between the resistor 70' and capacitor 71, and one of the base contacts is connected by conductor 75 to the actuating coil 67 of relay 66. The other side of the actuating coil is connected by conductor 76 to the side 72 of the power supply. The other base contact of the unijunction transistor 73 is connected through resistors 77 and 79 in series, to the side 69 of the power supply, with the junction 78 between resistors 77 and 79 connected through resistor 80 to side 72 of the power supply. Resistor 79 is preferably adjustable. This resistor and circuit arrangement produces a biasing voltage upon the unijunction transistor 73 which prevents sufficient current to pass to conductor 75 and through actuating coil 67 to cause the relay 66 to operate and move its switch arm 63 from its lower position. v

When switch arm 44 moves upward and engages contact 46, the circuit previously described through resistor 70 and capacitor 71 is completed and the capacitor 71 commences to charge. The voltage that builds up across capacitor 71 alters the bias upon the unijunction tran sistor 73, eventually to the point where the transistor 73 passes enough current to conductor 75 and through actuating coil 67 to cause relay '66 to operate and move its switch arm 63 to its upper position. This relay movement causes switch arm 63 to disengage contact 64 and thus break the circuit from the lower light responsive device 38 to its amplifier 54, via switch arm 47 of relay 43 and its contact 49. This circuit was initially completed upon the expiration of time interval TA (provided by time delay device 50)) when relay 73 was actuated, and is broken upon the expiration of time interval TB (provided by timing unit 68) when relay 66 is actuated.

If no light from light beam 36 impinges upon light responsive device 38 during the time interval TB when the light responsive device 38 is operatively connected to its amplifier 54, there is insuflicient output from the amplifier 54 to the actuating coil 55 of relay 56 to cause the relay to operate and move its switch arms 57 and 60 from their lower positions. This is what happens when a fully-filled bottle 16 is at, and is passing through, the checking station 26.

Assume, however, that an underfilled bottle 16 is at, and is passing through, the checking station 26.

The neck 24 of the bottle will interrupt the beam of light 30 to the upper light responsive device 32, and this will initiate time interval TA. During this time interval TA the bottle is moved by the upper run 14 of belt conveyor 10 to a position where the leading edge of the bottle 16 has passed the light beam 36 of the lower light source 34 and this light beam 36 is directed toward the central area of the bottle 16, as shown in FIG. 1. Then, after the bottle reaches this position, the time interval TA expires and relay 43 operates to initiate time interval TB. At this time very little, if any, of the light beam 36 traverses inside the glass wall of the bottle around from one side of the bottle to the other and then out to the lower light responsive device 38. Rather, the light beam 36 passes through the glass wall of the bottle at the side nearest the lower light source 34, passes through the bottle to the opposite side wall (since the bottle is underfilled), and then passes out of the glass wall of the bottle into the lower light responsive device 38. Such light impinging on device 38 causes enough current to flow to amplifier 54 (switch arm 63 then being in engagement with contact 64 and switch arm 47 then being in engagement with contact 49) to cause sufiicient current to flow from the amplifier 54 through the actuating coil 55 of relay 56 to cause the relay 56 to operate and move its switch arms 57 and 60 from their lower to their upper positions.

The movement of switch arm 60 from its lower position where it was in engagement with its contact 61, breaks the energizing circuit for the conveyor motor 12, and so stops the conveyor 10. It may also, if desired, cause a suitable signal light to light up. The stopping of the conveyor 10 and the lighting up of the signal light are indications to the person supervising the operation that an underfilled bottle has been detected and is located in the checking station 26 or just past it (where it was carried as the conveyor motor came to a stop).

' The function of switch arm 57 of relay 56, and its contact 59, is to complete a holding circuit for the actuating coil 55 of relay 56, once the relay has been caused to operate by an underfilled bottle. This holding circuit is from the side 69 of the power supply by way of conductor 86 to one terminal of the actuating coil 56, and from the other terminal of the actuating coil 55 by way of switch arm 57, contact 59 and normally-closed push button switch 87 to the other side 72 of the power supply. When the holding circuit for relay 56 is completed as described, the conveyor motor energizing circuit 85 remains broken at switch arm 60thus maintaining the conveyor stationaryuntil the operator, after removing the underfilled bottle from the conveyor, depresses push button switch 87. This action breaks the holding circuit for relay 56, so that the relay returns to its original, deenergized (lower) position, with the result that the motor 12 restarts and resumes its operation of the conveyor 10.

Switch 88 is a manually operated switch in the motor energizing circuit 85 to enable the operator to stop the conveyor motor 12 when desired, independently of the operation of the container filling and checking system.

Upon the expiration of time interval TB (as determined by the setting of timing unit 68), relay 66 operates and raises switch arm 63. This action opens the circuit (at switch arm 63) from the lower light responsive device 38 to the amplifier 54. This time interval TB is such, that it ends before the trailing edge of the bottle 16 comes into the path of the light beam 36 of the lower light source 34. Hence, there is a time interval TC, shown diagrammatically in FIG. 4, commencing upon the expiration of time interval TB, during which the lower light response device 38 is ineffective, although the bottle 16 is, at least in part, in the checking station 26.

During the latter part of time interval TC the light beam 36 from lower light source 34 tends to traverse inside the glass wall of the bottle, around from one side of the bottle to the other, regardless of whether the bottle is full filled or underfilled, and then to pass out from the bottle to the lower light responsive device 38. This, in the absence of this invention, and the time interval TB provided thereby to commence after the neck of the bottle 16 starts to pass under the upper light beam and to terminate before the trailing wall of the bottle comes into the path of the lower beam 36, will cause false indication of underfill for the bottle 16 in checking station 36, and an unnecessary shutting down of the conveyor 10. Such false indications of underfill are pronounced, in the absence of this invention, when bottles of small size are being checked for underfill, and particularly when the exterior diameter of the neck 24 of each bottle 16 is a substantial portion of the outside horizontal dimension of the side of the bottle parallel to the path of travel of the conveyor belt 14.

In an illustrative embodiment of the invention, the conveyor belt 14 operates at a speed of 28 feet per minute or 5.6 inches per second. The bottles 16 are known as 15 cc. amber rectangular bottles. Each such bottle 16 has a mean outside width on its broad side of inches (1.2187 inches), this being the side shown in FIGS. 1 and 4. The means outside diameter of the neck 24 of this bottle is 0.768 inch, measured at the base of the threads on the neck (which, for simplicity, are not shown). The mean outside neck diameter measured at the apex of the threads is 0.852 inch. The neck diameter (base) is thus about 63 percent of the width of the bottle in the direction of bottle travel.

In such embodiment, the setting of time delay device is such as to provide a time interval TA of approximately 0.04 second, and the setting of timing unit '68 is such as to provide a time interval TB of approximately 0.05 second. As the total time for the bottle to travel the distance of the neck diameter is approximately 0.14 second, the time interval TC works out to be approximately 0.05 second.

After the bottle 16 moves away from the checking station 26, the light beam 30 from the upper light source 28 strikes the upper light responsive device 32, but as it is a Dark operate" device, the relay 43 drops to its original, unenergized, lower position, in which its switch arm 44 is in engagement with its contact 45, and its switch arm 47 is in engagement with its contact 48, both as shown in FIG. 3. Hence, if the lower light beam 36 falls on lower light responsive device 38 due to the space between successive bottles on the conveyor 10, nothing happens at relay 56, as the circuit from the lower light responsive device 38 to the amplifier 54 is broken at the switch arm 47, which is then not in engagement with its contact 49. The container filling and checking system is thus reset and ready to check for underfill the next container on the conveyor 10.

It is to be noted that the operation of relay 56 might, through the intermediary of suitable, known mechanisms, automatically remove the underfilled bottle 16 from the conveyor belt 14, rather than, as disclosed, stop the conveyor and rely upon an operator to manually remove the underfilled bottle and restart the conveyor.

What is claimed is:

1. In a system for checking the underfill of containers made of transparent material with each container having at its top a neck which is integral with the body of the container and through which the container is filled, the system having a substantially horizontal, continuously moving conveyor belt on which the containers rest as they are moved to, through, and past the checking station, the checking station having two light responsive devices, one positioned above the other, each of which is controlled by the container at the checking station, with the lower light responsive device arranged to check for underfill of the containers and the upper light responsive device arranged to render the lower light responsive device effective upon the entry of a container in the checking station, the improvement in said system comprising:

(a) time delay means responsive to the entry of each container into the checking station, as determined by the interruption of the light beam to the upper light responsive device caused by the neck of the container entering such beam, for rendering the lower light responsive device ineffective to check for underfill of the container entering the checking station until the expiration of a predetermined time interval after the operation of such time delay means, and thereupon rendering the lower light responsive device effective to check for underfill of the container in the checking station; and

(b) timing means, responsive tothe action of said time delay means to render effective the lower light responsive means to check for underfill of the container in the checking station, for terminating the etfectiveness of said lower light responsive means to check for underfill of the container in the checking station at the end of a second predetermined time interval that commences substantially with the end of the first predetermined time interval and terminates well before the trailing wall of the container comes into the path of the light beam to the lower light responsive device.

2. A system as described in claim 1, in which the time interval provided by the time delay means insures that the effectiveness of the lower light responsive device to check for underfill of the container commences well after the leading wall of the container leaves the path of the light beam to the lower light responsive device.

3. A system as described in claim 1, in which the upper light responsive device is responsive to interruption of the light beam thereto by the neck of the container as the container enters the checking station, and the setting of the predetermined time intervals of the time delay means and the timing means are such that the lower light responsive means is effective to check for underfill only 7 during the period of time the center portion of the container is opposite the lower light responsive device.

4. A system as described in claim 3, in which the outside diameter of the neck of the container is over fifty percent of the horizontal dimension of the container in its direction of travel.

5. A system as described in claim 4, in which the container is made of glass.

References Cited UNITED STATES PATENTS 3,094,213 6/1963 Wyman 209-111] 5 WALTER STOLWEIN, Primary Examiner US. Cl. X.R.

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