Spray Dispenser Having A Capacitor Discharge Timer

Abstract

A spray dispenser for use with an aerosol spray container, the spray dispenser including a drive motor triggered by a time delay circuit to rotate a first cam from an armed position to a release position to release an actuator for opening the container valve, and also to rotate a second cam to subsequently operate a switch for connecting the drive motor to an energy source to drive the first cam to its armed position, at which point the switch is operated to disconnect the drive motor from the energy source.

Parent Case Text

This application is a continuation of our application Ser. No. 720,089, filed Apr. 10, 1968, now abandoned.

Description

RELATED APPLICATION

This application is related to the patent application of Charles M. Hart, Ser. No. 644,741, filed Mar. 20, 1967, now Pat. No. 3,388,834 and entitled "Spray Dispenser." The present application is different primarily in the structure which enables its operation over extended periods of time by low energy sources such as batteries.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a spray dispenser and more particularly to a battery operated dispenser adapted to automatically release a burst of spray from an aerosol container at regular timed intervals.

2. Description of the Prior Art

Deodorizing, germicidal, and medicinal materials are best dispersed into the atmosphere of a room or similar enclosure by incorporating such materials in aerosol cans or containers along with a pressurized, liquefied gas for common release in spray form. Such containers are normally provided with a valve having a projecting, axially slidable stem carrying a spray nozzle which serves also as a finger piece or actuator button for inwardly moving or depressing the valve stem. The valve is normally spring biased to a raised, closed position and is operated to release spray by manually or automatically depressing the spray nozzle.

For many applications manual actuation of the valves of such aerosol containers is entirely satisfactory. However, there are also many situations in which the dispersion of materials in spray form within an enclosed area must be uniform and closely controlled, such as in public restrooms, restaurants, and hospital sickrooms. In the past, this need for precise spray dispersion has been met by a variety of continuously driven automatic spray dispensers using synchronous motors or similar slow-speed drive units to operate a mechanism which periodically engages the spray nozzle of the aerosol container for actuation of the valve at regular, predetermined intervals.

Most of these prior art devices are of the type whose drive motors are powered by plugging them into a usual electrical outlet. The plug-in cord is unsightly and often in the way, and the dispenser is of course completely useless where no power source is available.

Although some dispensers are battery powered, they are generally continuously driven so that their operating life on a set of batteries is undesirably short.

SUMMARY

The present invention provides a spray dispenser which is relatively inexpensive to manufacture, reliable in operation, characterized by long service life on a set of batteries, and which permits rapid removal and substitution of aerosol containers for various materials, thereby adapting dispenser for multipurpose use. Since the present dispenser is battery powered, it can be used in or away from the home to provide automatic spray dispersion of a great variety of materials, depending only upon the nature of the contents of the aerosol container inserted in the dispenser.

The present dispenser utilizes a particular form of valve actuating mechanism and bias means to rapidly move the valve between its open and closed positions, thereby greatly reducing unwanted sputtering and leaking of the spray can contents on actuator and release of the spray valve.

The valve actuating mechanism and bias means of the present spray dispenser include actuating arms operative upon cam means which are coupled to the driven shaft of an electric motor, but in which the arms are urged only lightly against the cams by the bias means during the major portion of the operating cycle. The electric motor is therefore subjected to little or no load, and therefore uses comparatively little energy, except immediately prior to operation of the valve. At that time the bias developed is at a maximum to cock or arm the valve actuating mechanism.

The present dispenser is also characterized by a unique electronic time delay circuit which provides highly accurate timing of the desired interval between valve actuations. This circuit operates the drive motor for a short time period to effect actuation of the spray can valve and thereafter enable coupling of the drive motor directly to the batteries. The drive motor and batteries are decoupled after the valve actuating mechanism is cocked or armed for another cycle. At this time the time delay circuit again is operative to control the interval of time before another actuation of the spray container valve occurs. The drive motor is not driven during these periods so that energy drain on the batteries is negligible between valve actuations.

The present spray dispenser is constructed of relatively inexpensive sheet metal components, utilizes a low cost electric motor, and is adapted for energization by readily available "flashlight batteries," thereby reducing its price and enhancing its market appeal, particularly in areas where plug-in power is not readily available.

Other objects and features of the invention will become apparent from consideration of the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a front elevational view of a spray dispenser according to the present invention, the cover or front portion of the dispenser housing being removed for clarity, and the components being illustrated in their positions just prior to valve actuation;

FIG. 2 is a left side elevational view of the upper portion of the spray dispenser, the cover being illustrated in its raised or open position;

FIGS. 3 through 6 are front elevational views of the upper portion of the spray dispenser, and illustrating the positions of the components immediately after depression of the spray valve and prior to release of the holddown arm or trigger (FIG. 3); immediately after release of the holddown trigger (FIG. 4); shortly after engagement of the primary or upper arm by its cam (FIG. 5); shortly after engagement of the secondary or lower arm by its cam (FIG. 6); and

FIG. 7 is a wiring diagram illustrating the time delay circuit and its connection to the drive motor and a batter source of energy.

Referring now to the drawings, and particularly to FIGS. 1 through 6, there is illustrated a spray dispenser 10, according to the present invention, which comprises, generally, a frame or housing 12 which supports an aerosol can or container 14 having a metering valve 15; an actuator mechanism 16 having an actuator 18 continuously engaged with the valve 15, further having an upper or primary arm or lever 20 operative upon the actuator 18 to operate the valve 15, and further having a lower or secondary arm or lever 21, sometimes also referred to as a holddown trigger; a bias means or tension spring 22 urging the arms 20 and 21 toward one another; a drive means or direct current electric motor 24 having a driven shaft 26; and a cam arrangement 28 coupled to the driven shaft 26 and including primary and secondary cam surfaces or cams 30 and 32 engageable with the arms 20 and 21, respectively, to effect periodic actuation and release of the aerosol container valve 15.

The spray dispenser 10 is particularly adapted for use with an aerosol container having the metering valve 15, which is of that particular type having an internal spring or bias which always urges the valve 15 toward an outward or closed position. The valve 15 is movable from its closed position to a depressed position for releasing a single spray burst during the course of such movement. For this purpose, the valve 15 includes an elongated, projecting discharge valve stem which mounts an actuator button or spray nozzle at its outer end, the outer end being upwardly oriented in the drawings.

The container 14 and the valve 15 are well known to those skilled in the art and therefore only the general nature and function thereof will be described.

A common form of metering valve mechanism, and which operates satisfactorily with the present dispenser 10, includes a trap chamber past which the discharge valve stem moves during the course of its inward slidable movement when the spray nozzle 30 is depressed. Upon alignment of an inlet opening in the valve stem with the trap chamber, spray material in the trap chamber is driven under pressure through the hollow valve stem and out of the spray nozzle in a fine mist or atomized spray. The quantity of such spray is controlled or metered because of the fixed volume of the trap chamber. For each depression of the valve stem, only the quantity within the trap chamber is discharged through the nozzle.

As best viewed in FIGS. 1 and 2, the dispenser housing 12 is of two-part construction, including a back portion 34 and an overlying cover or front portion (not shown) which are both preferably fabricated of sheet metal. The front portion includes an opening to allow spray emission, and is conveniently pivoted (not shown) to the back portion 34. The back portion 34 includes a normally upstanding or vertical back 36, a forwardly projecting substantially rectangular base 38 which supports the aerosol container 14, an upper wall 40, and a pair of flanges 42. The flanges 42 structurally stiffen the housing 12 and also afford outward faces against which the front portion or cover slidably seats when the cover overlies the back portion 34.

The shelf 40 includes an opening to receive a snap action switch 44 for turning on the dispenser 10, as will be seen.

A U-shaped substantially-rectangular bracket 46 is secured to the upper portion of the housing back 36, the legs or flanges of the bracket 46 projecting it outwardly of the back 36 to define an open space for receiving the motor 24, certain of the other electrical components, and the wiring for the dispenser 10, as will be seen. The motor 24 is coupled to a suitable speed reduction mechanism (not shown) for providing a desired rate of rotation for the driven shaft 26. The motor 24 is preferably a direct current motor adapted for energization by a low energy source such as a pair of usual 1.5 volt size D flashlight batteries 48. Its substantially constant motor speed is reduced by the associated speed reduction mechanism to the desired rate so that, for example, the driven shaft 26 can be rotated once every few minutes when the motor 24 is operated.

The driven shaft 26 of the motor 24 projects through a suitable opening provided in the mounting bracket 46 and mounts the cam assembly 28 at its forward or projecting extremity for counterclockwise rotation, as viewed from the front of the dispenser. The shaft 26 preferably includes a flat (not shown) which mates with a complemental flat portion provided in the shaft-receiving opening of the cam assembly 28 to prevent relative rotation between the cam assembly 28 and the shaft 26.

The cam assembly 28 is preferably one, integral part made of a wear-resistant, somewhat resilient material such as Nylon or the like to eliminate metallic clicks during operation of the dispenser 10. The cam 28 includes a central portion of a particular thickness from which extends the radially projecting section which defines the cam 30. The cam 32 is defined by a greater width section, as best viewed in FIGS. 1 and 2, of the surface of the cam 30 in the area shown in dotted outline in FIG. 1, for example.

The cams 30 and 32 are generally in light engagement with the arms 20 and 21, as will be seen, but each of the cams 30 and 32 includes an abrupt dropoff point or fall for allowing the associated arm to suddenly move inwardly toward the shaft 26. Thus, the cams 30 and 32 initially move their associated arms 20 and 21 away from one another until the cam falls are encountered, at which time the released arm or arms moves rapidly and radially inwardly.

The upper arm 20 is an elongated sheet metal part pivotally mounted to the bracket 46 at one extremity by a rivet 50. The opposite or free extremity of the arm 20 includes a right-angular flange 52 whose undersurface normally engages some portion of the cam 30. In addition, the arm 20 is pivotally secured intermediate its extremities to the upper extremity of the actuator 18 by a rivet 54 for upward movement of the actuator 18 upon pivotal movement of the lever 20 in a clockwise direction. The lower extremity of the actuator 18 includes a right-angular flange 56 which rests upon the upper surface of the spray valve 15.

In its movement under the action of the lever 20, the actuator 18 slides vertically within a vertically elongated slide or track 58 integrally formed by indenting or punching the metal of the mounting bracket 46. The deformation is just sufficient to accept the actuator 18 and orient the front surface thereof flush with the front surface of the bracket 46. The actuator 18 is retained in position within the track 58 by a rivet 60 which is secured to the bracket 46, and which projects through a vertically elongated slot provided in the actuator 18. The head of the rivet 60 overlies the side margins of the slot, but is slidable thereover to enable vertical slidable travel of the actuator 18 in the track 58.

The lower arm 21 of the valve actuating mechanism 16 acts in the capacity of a trigger for suddenly releasing the valve 15, and for effecting electrical connection of the motor 24 to the batteries 48, as will be seen.

The lower arm 21 is elongated and pivotally mounted adjacent one extremity by a rivet 62 to the bracket 46 at a point adjacent the actuator 18. The opposite extremity of the arm 21 extends behind the cam 30 and includes a right angular flange 64 adapted to ride upon that widened portion of the cam 30 which constitutes the cam 32.

The cam 32, as previously indicated, is preferably integrally molded as a part of the cam assembly 28, the cam 32 commencing substantially at the location of the cam fall of the cam 30. The cam 32 terminates approximately diametrically opposite its beginning, that is, it extends approximately half-way around the center of the cam assembly 28. The particular lengths of the cam rises and cam falls of the cams 30 and 32 will be readily apparent to those skilled in the art after the operation of the dispenser 10 is explained hereinafter.

The actuator 18 is normally urged downwardly by the arm 20 which is biased downwardly by the spring 22, as best viewed in FIG. 1. The spring 22 is a tension spring having its upper extremity connected to the unpivoted extremity of the arm 20, and its opposite or lower extremity connected to the unpivoted extremity of the arm 21. The bias of the spring 22 is much stronger than the valve spring of the aerosol container 14 so that the bias of the valve spring is easily overcome by the bias developed by the spring 22 in the orientation of the components as shown in FIG. 1, whereby the spray nozzle 30 is maintained in its depressed position.

The normal biased depression of the spray valve 15 tends to firmly maintain the aerosol container 14 in engagement with the housing base 38 during operation of the spray dispenser 10.

The spray dispenser components thus far described could be continuously operated by continuous operation of the motor 24. However, the energy drain on the batteries 48 would be prohibitive. Consequently, the dispenser 10 includes a time delay circuit 66 which, in conjunction with the arm 21, is effective to cut off the power to the motor 24 shortly after each actuation of the valve 15, and recouple the motor to the batteries only after a predetermined interval of time has elapsed. Before describing the circuit 66, however, the operation of the remainder of the components will first be described to facilitate an understanding of the operation and great utility of the circuit 66.

Assuming the components of the dispenser 10 are in the cocked and armed positions illustrated in FIG. 1, and that the drive shaft 26 is rotated in a counterclockwise direction, as viewed in FIG. 1, the cam assembly 28 will rotate until the flange 52 of the arm 20 abruptly drops off the cam 30 under the bias of the stretched spring 22, as best viewed in FIG. 3. This movement of arm 20 abruptly and quickly drives the actuator 18 downwardly to effect sudden depression of the spray valve 15. During this movement of the spray valve 15 from its projected position to its depressed position, a single metered spray burst is released from the aerosol container 14. However, the arm 21 is at this time riding on its cam 32 and the spring 22 is sufficiently stretched to strongly bias the arm 21 radially inwardly against the cam 32, and also bias the arm 20 and the actuator 18 generally downwardly so that the spray valve 15 is biased closed.

As the counterclockwise rotation of the cam assembly 28 continues, the arm 20 is out of contact with the cam 30 and therefore the only frictional load upon the motor 24 at this time is by virtue of the engagement between the arm 21 and the cam 32.

The spray valve 15 is maintained in its depressed position by the bias of the spring 22 for only a very short interval, as will be seen from FIGS. 3 and 4, before the arm 21 drops off its cam 32 to suddenly release the bias in the spring 22, and thereby abruptly release the actuator 18 and the spray valve 15. Since both actuation and release of the valve 15 are very rapid, there is no tendency toward dribbling or leaking of spray material out of the spray nozzle opening.

The motor 24 continues to rotate the cam assembly 18, the assembly moving from the position shown in FIG. 4 to that shown in FIG. 6, and then on to the armed or cocked position of FIG. 1. It is noted that it is primarily only when the cam assembly 18 is being rotated from its position in FIG. 6 to that of FIG. 1 that the spring 22 is being stretched appreciably. Consequently, it is only during this short interval that there is any appreciable drain on the batteries 48. Next will be described the time delay circuit 66 and its associated components.

When the components of the dispenser 10 are in the positions illustrated in FIG. 4, the switch or arm 21 is closed, that is, in engagement with a terminal 98. The terminal 98 is constituted by an elongated, electrically conductive element 100 which is electrically insulatedly mounted at one extremity to the housing 12. It is made of a springy or resilient metal, with its opposite extremity adapted to underlie one end of the arm 21 when the two are in engagement. Such engagement establishes electrical connection between the frame 12, the arm 21, and the element 100, the element 100 normally being insulated from the frame 12 as previously indicated.

Closure of the arm or switch 21 occurs when one end of the arm 21 drops off the cam 32, as best viewed in FIG. 4. This causes the other end of the arm 21 to engage the element 100. This occurs simultaneously with the abrupt release of the spray valve 15 occasioned by relief of the bias in the spring 22.

The drive motor 24 operates during the stages shown in FIGS. 1 through 6 until the arm 21 engages its cam 32. As shown in FIG. 1, this rotates the arm 21 and breaks its electrical contact with the element 100 and cuts off the coupling of the motor 24 to the batteries 48.

Referring now to FIG. 7, the positive terminal of the batteries 48 is connected through the switch 44 to the metal frame of the housing 12. The negative battery terminal is connected through a lead 86 to one side of the drive motor 24 and also is connected in parallel with the emitter 88 of an NPN transistor 68. The output or collector 70 of the transistor 68 is direct coupled to the input or base 72 of a PNP transistor 74.

The base 90 of the transistor 68 is connected through the resistor 84 to a junction of a timing capacitor 80 and a timing resistor 82. One side of the capacitor 80 is connected through a lead 92 to the collector 76 of the transistor 74, and also is connected to the terminal 98 and to the drive motor 24 through the lead 78.

The opposite side of the capacitor 80 is connected to the timing resistor 82, as previously indicated, and the resistor 82 in turn is connected to the emitter 94 of the transistor 74, and in parallel with a lead 96 which is connected to the electrically conductive frame or housing 12 of the dispenser 10.

The electronic time delay circuit 66 thus comprises a transistorized timer and a transistorized switch, the timer including a resistance-capacitance circuit composed of the timing resistor 82, the timing capacitor 80, a current limiting resistor 84, and the transistor 68. The transistorized switch includes the transistor 74.

The transistor 68 conducts current when the voltage applied to the emitter 88 is made negative with respect to both the collector 70 and the base 90, and the voltage applied to the collector 70 is made positive with respect to both the emitter 88 and the base 90.

The transistor 74 conducts current when the voltage applied to the emitter 94 is made positive with respect to both the collector 76 and the base 72, and the voltage applied to the collector 76 is made negative with respect to both the emitter 94 and the base 72.

The polarity and value of the voltages applied to the collector and emitter of transistors 68 and 74 in circuit 66 remain fairly constant. Therefore, the following description is directed only to the changes of voltage applied to the base of transistors 68 and 74.

The transistor 68 functions as a blocking oscillator. It conducts entries for a short period of time when the voltage applied to the base 90 is made slightly positive, but is cut off for a much longer period when the voltage applied to the base 90 is zero or negative.

The transistor 74 functions as an overdriven amplifier. When the voltage applied to the base 72 is made less positive than the voltage applied to the emitter 94, the transistor 74 is driven from the cutoff or nonconduction stage to the saturation or full-conduction stage.

The initial flow of current from the battery 48 to the drive motor 24 is controlled by the transistor 74. The functioning of transistor 74 is controlled by the transistor 68, which in turn is controlled by the voltage charge in the capacitor 80.

When the components of the present dispenser 10 are in the positions illustrated in FIG. 1, and the switch 44 has just been closed, a small current from the battery 48 flows through the drive motor 24 and the timing resistor 82, placing a very small voltage charge in the timing capacitor 80 with the positive value at the junction of resistors 82 and 84. This positive voltage is applied through the current limiting resistor 84 to the base 90 of the transistor 68, causing this transistor to conduct a small current from the negative side of the battery 48 through transistor 74 to the positive side of the battery 48.

At this time the current through transistor 74 causes a voltage drop at the base 72. This voltage being less than the voltage at the emitter 94, this causes the transistor 74 to conduct current from the negative side of the battery 48 through the drive motor 24 to the positive side of the battery.

The flow of current through the drive motor 24 and the transistor 74 operates the motor 24. While the motor 24 is operating, the timing capacitor 80 is discharging through transistor 68 and 74 and charging in the opposite direction through leads 78 and 92, and at a rate determined by the resistance of the current limiting resistor 84 and the capacitance of timing capacitor 80. When the capacitor 80 is recharged, the polarity of the voltage at the junction of resistors 82 and 84 is negative. This negative voltage is applied through the resistor 84 to the base 90 of the transistor 68, causing it to cut off. With no current flowing in the collector 70 of transistor 68, the voltage at the base 72 of transistor 74 increases and becomes equal to the voltage at the emitter 94, causing transistor 74 to cut off the current flowing through the motor 24.

At this point the motor 24 would ordinarily stop. However, by this time the components are in the positions illustrated in FIG. 4, and the switch 21 has been closed. In so doing the switch 21 thereby connects the motor 24 directly to battery 48.

Closing of the switch 21 also connects the battery 48 directly to timing capacitor 80 and keeps this capacitor fully charged. Transistor 68 is maintained in a cutoff condition by this charge, as previously described.

When the dispenser components reach the positions shown in FIG. 1, the switch 21 has opened. The timing capacitor 80 is slowly discharged through timing resistor 82 and is charged with a very small voltage of reverse polarity which is positive at the junction of resistors 82 and 84. This positive voltage applied to the base 90 causes transistor 68 to conduct again and restart the operating cycle. The time that it takes for the above discharge and charge operation is equal to the time constant of timing resistor 82 and timing capacitor 80.

The electronic time delay circuit 66 will function as long as the battery is capable of operating the drive motor.

The total time delay of this circuit, typically 15 minutes, is the sum of the time intervals for timing capacitor 80 to accumulate the positive voltage bias, for the drive motor 24 to complete one operating cycle, and for timing capacitor 80 to discharge a full charge. It is noted that when voltage is applied to the circuit 66 for the first time, the time delay prior to the first operating cycle is considerably shorter than subsequent time delays.

An increase in the value of the particular resistor 82 utilized would increase the time off, and decrease the current used by the circuit 66. Decreasing the value of the resistor 82 would have just the opposite effect. Increasing the value of the capacitor 80 would increase the time off, the time on, the power output, and the current used by the circuit 66; while decreasing the value of the capacitor 80 would have just the opposite effect. Increasing the value of the resistor 84 would increase the time on and decrease the power output, while decreasing the value of the resistor 84 would have just the opposite effect. The intervals of time off and time on could therefore be adjusted, if desired, by making the resistors 82 and 85 variable and providing suitable knobs (not shown) to adjust them.

The supply voltage of the batteries 48 is determined by the requirements of the drive motor 24. In this regard, it has been found that two conventional 11/2 -volt flashlight batteries provide sufficient power to operate the drive motor 24 for periods in excess of 12 months. In effect, the operating life of the batteries is about that of their shelf life. This is due to the short usage of the batteries in a normal operating cycle, which typically involves actuation of the drive motor 24 for only approximately 2 minutes out of every hour.

The DC working voltage of the capacitor 80 is preferably equal to or higher than the voltage of the batteries 48. For most medium and low power applications it has been found that the value of each of the resistors 82 and 84 can be made approximately one-half watt. General purpose and audio amplifier transistors are satisfactory for use in the circuit 66.

From the foregoing, it is apparent that a battery operated spray dispenser has been provided which is adapted to effect uniform spray dispersion of material over a prolonged period of time by reason of the spaced apart intervals of operation of the drive motor by the batteries. The dispenser is relatively inexpensive to manufacture, is characterized by reliable, trouble-free and noise-free operation, and is adapted to quickly accept different aerosol containers for spraying any of a variety of materials.

Various modifications and changes may be made with regard to the foregoing detailed description without departing from the spirit of the invention.

Claims

We claim:

1. A spray dispenser for use with an aerosol container having a metering valve mechanism which includes a spray valve movable to an operative position to release a spray burst of pressurized material from the container, said spray dispenser comprising:

a frame for supporting an aerosol container; a drive means, a source of electrical energy, and first switch means adapted upon closure to allow current flow from said source to said drive means for energizing said drive means;

valve actuator means coupled to said drive means and to said first switch means and having an armed condition, a release condition and a switch closure condition, said actuator means in said armed condition being operative to maintain said first switch means open and said spray valve inoperative;

said actuator means in said release condition being operative to operate said spray valve;

said actuator means in said switch closure condition being operative to close said first switch means whereby said drive means is energized to move said actuator means from said switch closure condition to said armed condition and thereby open said first switch means to deenergize said drive means; and

a time delay circuit including a capacitor and second switch means in parallel with said first switch means and operative upon charging of said capacitor to a predetermined first potential to block current flow through said second switch means, and operative upon discharging of said capacitor to a predetermined second level to allow current flow through said second switch means to energize said drive means for movement of said valve actuator means from said armed condition to said release and switch closure conditions, said capacitor being charged to said first potential during movement of said valve actuator means from said release condition to said armed condition.

2. A spray dispenser according to claim 1 wherein, upon energization of said drive means through said second switch means, said valve actuator means moves into said release condition prior to movement into said switch closure condition.

3. A spray dispenser according to claim 1 wherein said actuator means includes a cam assembly and said first switch means includes an arm engageable upon a cam surface of said cam assembly for said closure of said first switch means.

4. A spray dispenser according to claim 1 wherein said actuator means includes a first cam and an actuator arm cooperative with said first outlined for said operation of said spray valve;

wherein said actuator means further includes a second cam, and said first switch means includes a switch arm cooperative with said second cam for closing said first switch means.

5. A spray dispenser according to claim 4 and including bias means engaged upon and biasing said actuator arm and said switch arm toward said first cam and second cam, respectively.

6. A spray dispenser according to claim 1 wherein said drive means is a direct current motor and said source of electrical energy is a battery source.

7. A spray dispenser according to claim 1 wherein said time delay circuit includes resistance means defining with said capacitor a resistance-capacitance circuit, and wherein the values of said capacitor and said resistance means are primarily determinative of the time interval between releases of spray bursts from the aerosol container.

8. A spray dispenser according to claim 1 wherein said second switch means includes a transistor connected to said capacitor and operative as a blocking oscillator.

9. A spray dispenser according to claim 1 wherein said second switch means includes a resistor and a pair of complementary NPN and PNP transistors, the base of the NPN transistor being connected through said resistor to said capacitor, and the collector of said NPN transistor being direct-coupled to the base of the PNP transistor.

10. A spray dispenser according to claim 9 and including a timing resistor in circuit with said capacitor to aid in controlling the rate of discharge of said capacitor.

11. A spray dispenser for use with an aerosol container having a valve mechanism which includes a spray valve movable to an operative position to release a spray burst of pressurized material from the container, said spray dispenser comprising:

a frame for supporting an aerosol container;

a drive means;

a source of electrical energy;

first switch means adapted upon closure to allow current flow from said source to said drive means for energizing said drive means;

valve actuator means coupled to said drive means and to said first switch means and having an initial condition in which said first switch means is open and said spray valve is inoperative, a valve actuation condition in which said spray valve is operated, and a switch condition in which said first switch means is closed whereby said drive means is energized to move said actuator means from said switch condition to said initial condition and thereby open said first switch means to deenergize said drive means; and

a time delay circuit including a capacitor and second switch means in parallel with said first switch means and operative with said capacitor charged at a predetermined first potential to block current flow through said second switch means, and operative with said capacitor charged at a predetermined second level to allow current flow through said second switch means to energize said

means for movement of said valve actuator means from said initial condition to said valve actuation and switch conditions, said capacitor being returned to said first potential prior to return of said valve actuator means to said initial condition.

12. A spray dispenser for use with an aerosol container having a valve mechanism which includes a spray valve movable to an operative position to release a spray burst of pressurized material from the container, said spray dispenser comprising:

a frame for supporting an aerosol container;

a drive means;

a source of electrical energy;

first switch means adapted upon closure to allow current flow from said source to said drive means for energizing said drive means;

valve actuator means mechanically coupled to said drive means and to said first switch means and having an initial condition in which said first switch means is open and said spray valve is inoperative, a valve actuation condition in which said spray valve is operated, and a switch condition in which said first switch means is closed whereby said drive means is energized to move said actuator means from said switch condition to said initial condition and thereby open said first switch means to deenergize said drive means; and

electrical means for periodically energizing said drive means to drive said actuator means, said electrical means including a timing capacitor connected for charging to a first potential during said switch condition and slowly discharging to a second potential during said initial condition to provide a time delay in the energization of said drive means.

13. A spray dispenser for use with an aerosol container having a valve mechanism which includes a spray valve movable to an operative position to release a spray burst of pressurized material from the container, said spray dispenser comprising:

a frame for supporting an aerosol container;

a drive means;

a source of electrical energy;

first switch means adapted upon closure to allow current flow from said source to said drive means for energizing said drive means;

valve actuator means coupled to said drive means and to said first switch means and having an initial condition in which said first switch means is open and said spray valve is inoperative, a valve actuation condition in which said spray valve is operated, and a switch condition in which said first switch means is closed whereby said drive means is energized to move said actuator means from said switch condition to said initial condition and thereby open said first switch means to deenergize said drive means; and

electrical timing means including second switch means in parallel with said first switch means and timing capacitor means connected for charging to a first potential during the motion of said actuator means from said switch condition to said initial condition, said capacitor thereafter discharging over a selected time period to a second potential, said second switch means being responsive to said second potential to energize said drive means.