Method and apparatus for testing aerosol spray devices

Jan, 17, 1967

D. E. M1LHOLLAND

3,298,518

METHOD AND APPARATUS FOR TESTING AEROSOL SPRAY DEVICES

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SOUND

LIGHT

REJECT

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CYCLE 2

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TIME (O.Ol SECONDS)

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United States Patent Office

3,298,518

Patented Jan. 17, 1967

3,298,518

METHOD AND APPARATUS FOR TESTING AEROSOL SPRAY DEVICES

Dick E. Milholland, Racine, Wis., assignor to S. C. Johnson &amp; Son, Inc., Racine, Wis.

Filed Mar. 29, 1965, Ser. No. 443,219

Claims. (Ci. 209—111.9)

This invention relates to the testing of aerosol spray devices or spray cans, and more particularly it concerns a method and apparatus for rapidly and accurately testing the operativeness of individual aerosol spray cans while they proceed along an assembly line.

In recent years, aerosol spray devices have achieved widespread popularity, as well as a greatly expanded field of application. As a result of this, there has been a heavy demand for these items; and this in turn has occasioned the development of improved and more rapid production techniques. There has remained one step in the manufacturing process, however, which has been particularly difficult to adapt to increased production rates. This step involves the testing of finished devices for operativeness and quality of spray.

In the past, aerosol spray devices were tested by manual actuation and visual observation of the devices as they proceeded along a conveyor or assembly line. This was undesirable however, for prior to actuation, each individual spray device had to be pre-aimed at a target so that it would not spray against the observer. As production rates increased, the time involved in aiming the spray devices became more and more of a hindrance. In order to maintain high production rates, it ultimately became necessary to divide the conveyor or assembly line into a plurality of parallel branches with at least one observerinspector stationed at each branch. In this way, each inspector would have more time to aim and test the particular Spray devices which passed along his branch.

According to my invention, it is now possible to test the operativeness and quality of aerosol spray devices or spray cans with high accuracy and with such rapidity that production rates in the order of 300 cans per minute can be accommodated with ease. Furthermore, such testing can be carried out in fully automatic fashion and without any necessity for dividing the conveyor or assembly line into several branches. In fact, only a minimum of alteration is necessary to conventional assembly lines.

These unique results are achieved, according to my invention by actually eliminating the need for orienting or aiming the individual spray cans prior to their actuation; and further, by eliminating the need for any visual observation of the spray discharge from the aerosol devices.

Essentially, my invention consists in the recognition and application of the fact that an aerosol spray device, or spray can, when actuated, produces a sonic disturbance whose frequency and amplitude are functions of the intensity and degree of fineness of the spray. This sonic disturbance, moreover, is omnidirectional and thus is substantially completely independent of the direction in which the spray can is facing at the time of its actuation.

I practice my invention by actuating individual spray cans in the presence of. a sonic detector tuned to a frequency range which corresponds to the range of sonic frequencies produced by operative spray cans when they are producing an acceptable quality of spray. The cans are actuated automatically. This is accomplished by providing a wheel so positioned on the assembly line that the cans traveling down the line will pass under the wheel in succession. As each can passes under the wheel its valve top is pressed down by the wheel to actuate its spray mechanism. If the spray mechanism functions properly, an acceptable sonic signal will be generated. This signal is sensed by the sonic detector which acts to permit the can to proceed down the assembly line. If, however, the spray mechanism functions improperly, or not at all, then a proper sonic signal will not be produced and the sonic detector will operate to actuate a reject mechanism for diverting the unacceptable spray can from the assembly line.

In a particular application, to be described in detail hereinafter, I provide a spray can detecting device, such as a photosensitive cell located in the assembly line slightly beyond the actuating wheel. This spray can detecting device is arranged to operate a reject mechanism each time it detects the presence of a can. The reject mechanism, when actuated operates to remove the detected can from the assembly line. The sonic detector is arranged such that when it detects the occurrence of an acceptable spray, it operates to disconnect the can detector from the reject mechanism. Thus, when an acceptable spray can passes along the assembly line, the sonic signal generated by the actuation of its spray mechanism will cause the sonic detector to disengage the reject mechanism so that when the presence of the can is detected immediately thereafter the reject mechanism will not operate and the can will proceed down the line. If, on the other hand, the spray mechanism is unacceptable, no output will be produced by the sonic detector and the can detector will remain effective to operate the reject mechanism for removing the can from the line.

There has thus been outlined rather broadly the more important features of the invention in order that the detailed' description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of the invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope of the invention.

A certain embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawing, forming a part of the specification, wherein:

FIG. 1 is a schematic representation of a system used in practicing the present invention; and

FIG. 2 is a timing diagram useful in considering the operation of the system of FIG. 1.

In FIG. 1, a portion of an assembly line 10 is shown with a series of completed aerosol containers or spray cans 12 moving therealong in the direction of an arrow 14. The containers 12 are positioned upright on a moving belt 16 and are guided between rails 18 which extend along the assembly line on each side thereof.

The aerosol containers 12 are each provided with a depressible actuator button 20 at the top thereof. The actuator buttons themselves have nozzle openings 22 through which aerosol mist or spray passes when the buttons are depressed. It will be noted that while the containers 12 themselves are aligned in upright position on the belt 16, their actuator buttons 20 are randomly oriented so that the nozzle openings 22 will direct spray in different directions from one container to the next.

There are provided a testing station 24 and a reject station 26 in close positional relationship along the assembly line 10. The testing station 24 includes a cam wheel 28 mounted by means of an arm 30 centrally above the belt 16 with its axis transverse to the belt so that as each aerosol container passes under the wheel 28, the actuator button 20 at the top of the container becomes depressed by the wheel. Thus, as each container passes under the

3,298,518 wheel it becomes actuated thereby for a short period of time.

Immediately adjacent the cam wheel 28 there is provided a sound transducer, such as a microphone 32, mounted on an arm 34. The microphone 32 is connected 5 to a first amplifier 36; and in conjunction with the amplifier it produces electrical signal representative of the acoustical disturbances produced by the spray emanating from an actuated aerosol container. The amplifier 36 is provided with filter means designed to attenuate all signals ₁₀execpt those resulting from a properly functioning container. In this manner, the system is protected from the effects of extraneous and incidental noises in the vicinity of the testing station.

At the reject station 26, the guide rails 18 terminate 15 to leave a space 37 through which any improperly functioning containers are removed from the assembly line 10. Across from the space 37 there is provided an air hose 38 which is connected to a source of high pressure air (not shown). The air hose 38 terminates at a nozzle 20 40 which is positioned to direct blasts of high pressure air across the belt 16 toward the space 37. Thus any container on the belt and in alignment with the space 37 will be blown off the belt and into the space upon a blast of air from the nozzle 40. 25

An air valve 42 is interposed along the hose 38 to control the blasts of air through the nozzle 40. The air valve 42 is actuated to allow a blast of air out through the nozzle by means of an electrical solenoid 44, which in turn is arranged in an electrical circuit to be described 30 more fully hereinafter.

There is also provided at the reject station 26 a photoelectric detection arrangement comprising a light source 46 on one side of the belt 16 and a photoelectric detector 48 on the opposite side of the belt. Whenever a container 35 12 passes through the reject station it interrupts light from the source 46 and thus casts a shadow on the photoelectric detector 48. The photoelectric detector in turn responds to this shadow by producing an electrical output signal.

The various components described above are intercon- 40 nected by means of an electrical circuit arrangement. This arrangement includes a first relay 50 connected to be energized by the output of the first amplifier 36. Thus, whenever a properly operating spray container 12 passes under and is actuated by the wheel 28, the sounds which 45 accompany the emission of spray therefrom are detected in the microphone 32 and converted into electrical signals which are amplified in the amplifier 36 and used to energize the first relay 50. The first relay 50, when energized, operates a movable arm 52 of a single-pole- 50 double-throw switch arrangement. The movable arm 52 is connected to the output of a second amplifier 54 which receives output signals from the photoelectric detector 48. Thus whenever the photoelectric detector 48 produces signals as a results of the passage of a container 12 through 55 the reject station 26, the movable switch arm 52 receives a finite voltage from the second amplifier 55.

The movable switch arm 52 of the first relay 50 is normally in contact with a first stationary terminal 56 connected to a second relay 58; but is movable away 60 from that terminal during energization of the first relay 50 to contact a second stationary terminal 60 connected to the energization circuit of the first relay.

The second relay 58, when energized, closes a pair of normally open switch contacts 62 to connect a voltage 65 source 64 in closed circuit with the solenoid 44 which actuates the air valve 40.

During operation of the system, each aerosol container 12 on the assembly line 10 is moved along under the cam wheel 28 by the moving belt 16 so that its depressible 70 actuator button 20 is pressed downwardly by the wheel. If the container sprays properly it will emit a certain sound which is detected by the microphone 32 and amplified in the first amplifier 36 whose output in turn causes energization of the first relay 50. The relay 50 in turn moves its 75 switch arm 52 so that it becomes disconnected from the first stationary contact 56 and becomes connected to the second stationary contact 60. As a result of this, the circuit connection to the second relay 58 is broken and it is thus incapable of closing the contacts 62 to actuate the air valve solenoid 42. Accordingly, the container 12, whose spray mechanism was operating properly, is not blown off the belt 16. If, on the other hand, no spray or an improper spray was produced as the container 12 passes under the cam wheel 28, the microphone 32 and amplifier 36 do not produce any signal to energize the first relay 50. Consequently, the circuit connection between the second amplifier 55 and the second relay 58 remains intact so that when the improperly operating container passes through the reject zone 26, the signal produced by the photoelectric detector 48 in response to the shadow cast thereon by the improperly functioning container, will cause the second amplifier 55 to produce an output which energizes the second relay 58. This in turn closes the contacts 62 placing the valve actuating solenoid 44 in circuit with the voltage source 64 to operate the air valve 42 and cause a blast of air from the nozzle 40 to blow the improperly functioning container off the belt 16.

Because of the high speed at which the containers 12 proceed along through the testing and reject stations 24 and 26, these stations must be displaced by a finite amount along the assembly line, or the reject mechanism would be incapable of operating swiftly enough to reject an improperly functioning container. On the other hand, the displacement of the belt and reject stations presents certain other problems. For example, since it is the passage of a properly functioning container through the test station which deactivates the reject mechanism, if the stations are too widely separated, a properly functioning container 12 will have passed completely through the test station by the time it reaches the reject station so that the test station would no longer be operative to deactivate the reject mechanism.

The arrangement of the present invention overcomes the above difficulty in a very reliable manner. According to this arrangement, the test and reject stations 24 and 26 are spaced closely enough so that a small amount of overlap in the timing of their respective operations occurs as a container passes through them. Also the circuit arrangement is such that this overlap is effective to cause the output of the second amplifier 54 at the reject station to actually maintain the reject mechanism in a deactivated condition if the first relay 50 had been in operation during the overlap period.

The timing diagram of FIG. 2 is useful in visualizing the cooperative interaction of the test and reject stations 24 and 26 to prevent inadvertent rejection of properly operating containers. Cycle 1 of FIG. 2 illustrates the timing for the case where a properly operating container has passed through the two stations 24 and 26. As the container passes through the test station 24 its spray top becomes actuated by the cam wheel 28 and a spray and an accompanying sound are produced beginning at a time T=0. This spray and its accompanying sound continues while the containers pass under the wheel 28; and it lasts for about 0.02 second. During this time, the first relay 50 is energized and its movable switch arm 52 is maintained down against the lower or second stationary contact 20. Prior to the expiration of the 0.02 second interval (at approximately T=0.01), the container 12 enters into the reject station 26 and begins to interrupt the light beam so as to cast a shadow on the photoelectric detector 48 which in turn causes the second amplifier 55 to produce a finite output voltage. This “light” controlled output voltage lasts for about 0.04 second (from 7=0.01 to 7=0.05). The voltage output from the second amplifier 54 is applied to the movable switch arm 52 of the first relay 50; and because this arm is connected via the second stationary contact 60 to the energization circuit of the first relay 50, the output voltage

3,298,518 of the second amplifier 54 will maintain the first relay 50 in its energized state even after the first amplifier 36 ceases to produce its relay energizing output. Consequently, the second relay 58 will not operate at all during the passage of the container 12 through the reject station 26 even though this station is separated from and not continuously acted on by outputs from the test station 24.

Cycle 2 of FIG. 2 illustrates the timing arrangement for the situation where an inoperative container passes through the test and reject stations. Since the inoperative container will not produce an acceptable sonic output, no sound signal is produced in its passage through the test station 24. Thus, the first relay 50 remains unenergized and its movable switch arm 52 is maintained in contact with the first stationary contact 56 and in circuit with the second relay 58. As the inoperative container passes into the reject station 26, it interrupts the beam from the light source 46 and casts a shadow on the photoelectric detector 48 which in turn causes the second amplifier 54 to produce an output which, by virtue of the position of the movable terminal 52, causes energization of the second relay 58. This relay in turn closes the normally open switch 62 to place the solenoid 44 into circuit with the voltage source 64. The air valve 42 then operates to allow a blast of air to blow the inoperative container off the belt 16 and out through the space 37.