Aerosol Dispensing Apparatus Having Disc-shaped Solenoid-actuated Plunger

Abstract

An aerosol dispenser having a housing defining a chamber. The housing is adapted to be attached to an aerosol container to permit spraying liquid to leave the container and enter the chamber. An outlet opening in the top of the chamber leads from a valve seat in the chamber to a spray tip and a seal assembly is normally held in sealing engagement on the seat by pressure in the container. An electromagnetis coupled to the body and is operable to draw a plunger downwardly to move the seal assembly off the valve seat to periodically dispense a predetermined quantity of spraying liquid from the container.

Description

This invention relates to apparatus for automatically and periodically dispensing pressurized spraying liquid from an aerosol container.

There are three basic types of devices for dispensing liquid from an aerosol container. The first type is adapted to be coupled to an alternating current supply and has an electric motor which runs continuously. As the motor rotates, it actuates an arm which periodically depresses a valve on the container to discharge spraying liquid. Although this type has the advantage that it is relatively quiet in operation, it has the distinct disadvantage that because it should be mounted on a wall, an unsightly electrical connection must be provided between the device and an electrical outlet.

A second of the types has a dry cell type of battery which is used to drive a small direct current electric motor. The motor is actuated periodically to expand a spring relatively slowly so that the current drawn from the battery is kept to a minimum for improved battery life. After a predetermined time interval, a time delay circuit trips a release mechanism which allows the energy stored in the spring to depress a valve of an aerosol dispenser. Devices of this type are satisfactory where noise is not a critical factor, but are not entirely suitable for use in places where noise would disturb people in the vicinity of the device.

The third type of device also uses a battery which is coupled through a time delay circuit to a solenoid. The time delay circuit energizes the solenoid periodically to open an aerosol valve thereby dispensing a predetermined quantity of spraying liquid contained in a measuring chamber. The valve remains open until all of the liquid in the chamber is dispersed whereupon the valve closes and more spraying liquid enters the chamber. In a variation of this third type, the chamber is connected directly with the aerosol container and the aerosol valve is opened for a predetermined time during which the liquid is sprayed from the device.

Devices of the third type have included seals at the solenoid valve to prevent loss of spraying liquid when the solenoid is not actuated, these seals are often attacked by the spraying liquid causing the seals to swell. As a result the aerosol valve no longer opens sufficiently to provide a proper spraying action.

According to a particular preferred embodiment of the present invention, apparatus is provided for automatically and periodically discharging an aerosol. The apparatus is generally cylindrical, having a longitudinal axis and includes an electromagnet constructed concentrically about an axial inlet tube which is adapted to fit into the dispensing opening of an aerosol valve to depress the valve. The electromagnet is contained in a lower housing and an upper housing defines a chamber and houses a plunger located above the electromagnet. A non-magnetic seal is located loosely in an inlet opening defined by the inlet tube and has a resilient seal at its outer end for engaging against a valve seat defined in the upper housing. The plunger has a central opening for clearing the valve seat so that when the electromagnet moves the plunger downwardly, the plunger engages the seal assembly and moves the seal assembly downwardly and away from the valve seat so that aerosol liquid is free to pass from the chamber and through an outlet opening associated with the valve seat. Once the electromagnet is de-energized, pressure from the aerosol lifts the seal assembly upwardly and the seal again engages against the valve seat to seal the chamber. Should the seal swell, the seal assembly is moved down the inlet opening and does not affect the movement of the plunger.

The invention will be better understood with reference to the drawings, wherein:

FIG. 1 is an exploded perspective view of a device built according to the invention; and

FIG. 2 is a sectional side view on the longitudinal axis of the device with the device engaged in the top of an aerosol can.

Reference is made to the drawings with particular reference to FIG. 2. A generally cylindrical dispensing device 10 is adapted to snap-fit into a rolled collar 12 on an aerosol container 14 for periodically dispensing aerosol spray. The device includes a housing 15 having a lower housing 16 and an upper housing 17. Lower housing 16 contains an electromagnet 18 for operating a valve 20 which is normally held closed by aerosol pressure when the device is attached to the pressurized aerosol container 14. As seen in FIG. 2, upon activating the electromagnet 18, the valve 20 is opened and a quantity of aerosol spraying liquid is discharged through a conventional spray tip 23.

The device 10 is preferably used on an upright aerosol container as shown in FIG. 2, and will be described in this position with a vertical longitudinal axis. However, the device may be used in any other position including the inverted position with suitable aerosol containers as will be described.

The lower housing 16 has an upper tubular portion 24 which is integrally attached at its lower end to a wall 26 having a central axial opening 28. A lower tubular portion 30 extends downwardly from the wall 26 for engaging in an annular ring 32 for coupling the lower housing 16 to the aerosol container 14. The upper tubular portion 24 is threaded externally for engaging in internal threads 34 in upper housing 22, and a pair of diametrically spaced lugs 36, 38 are provided intermediate the tubular portions 24, 30 for attaching the device to a casing (not shown). An axial slot 40 in the inner wall of the upper tubular portion 24 terminates at its lower end at a generally rectangular recess 42 in the wall 26 to provide clearance for electrical conductors 44 on coil 46 of electromagnet 18. The conductors pass upwardly in slot 40 and over the top of the lower housing 16 before engaging in an external axial slot 49 in the upper tubular portion 24 of the lower housing 16.

Annular ring 32 has inner and outer skirts 48, 50 extending downwardly from the top of the ring. Axial slots 52 are formed in outer skirt 50 to weaken the skirt for engaging the ring 32 in bead 12 of aerosol container 14. The skirt 50 defines an annular recess 54 for receiving bead 12 to locate the ring 32 on the container 14.

Axial slots 56 are also provided in inner skirt 48 to permit the skirt 48 to flex for engaging an inwardly extending, radial enlargement 58 on skirt 48 in an annular recess 60 defined externally on lower tubular portion 30 of lower housing 16. The annular recess 54 and the radial enlargement 58 are positioned axially relative to one another so that with the ring 32 on the container 14, the lower housing 16 is automatically aligned with an aerosol valve 62 and located axially to hold the valve 62 open as will be described.

The electromagnet 18, as previously described, includes the coil 46 and electrical conductors 44. The coil 46 is wound about a bobbin 64 for engagement in an annular recess 66 extending axially downwardly of a core 68 and terminating at a bottom wall 70. An internal tubular portion 72 extends upwardly from the wall 70 and is defined by the annular recess 66. The portion 72 has an axial opening 74 defining an upper part of an inlet opening through which aerosol spraying liquid passes to the valve 20. A pair of holes 76, 78 are provided in bottom wall 70 and are diametrically spaced about the tubular portion 72. Hole 78 receives a locating stub 80 on the wall 26 of lower housing 16, the stub being diametrically spaced from the rectangular recess 42. When the stub 80 is positioned in hole 78, the recess 42 is aligned with hole 76 for receiving conductors 44.

As better seen in FIG. 2, the bobbin 64 engages relatively tightly in the annular recess 66 and is sealed in place by a frictionally engaged plastic washer 82.

The upper housing 22 has a top wall 84 from which a hexagonal projection 86 extends upwardly. The projection 86 permits a wrench to be attached to the upper housing 22 for threadably engaging the upper housing 22 on the lower housing 16. The wall 84 defines three co-axial and stepped recesses 88, 90 and 92. The lower recess 88 is of a diameter to locate the upper end of core 68 for sealing engagement against the core to prevent loss of aerosol fluid from between the upper and lower housings. Intermediate recess 90 and upper recess 92 together define a chamber in which a plunger 94 moves in response to a magnetic field set up by the electromagnet 18. The plunger is free to move only in the portion of the chamber defined by the recess 90 so that it will not stick to the upper extremity of the chamber. A central opening 96 in the plunger 94 provides clearance for moving over a valve seat 98 extending downwardly from the top wall 84 of the housing 22. The valve seat 98 is adapted to sealably engage a seal assembly 99 having a resilient plug 100, part of which is frictionally engaged in an axial recess 102 at the upper end of a non-magnetizable rod 104. Recess 102 includes three inwardly extending axial ribs 106 for frictionally engaging the plug 100 and providing radial clearance for expansion of the plug should the aerosol spraying liquid attack the plug causing it to swell. This clearance also facilitates engaging the plug 100 in the rod 104. However, if preferred, the ribs 106 can be omitted.

Rod 104, is a loose fit in the upper part 74 of the inlet opening so that pressure from the aerosol can tends to force the plug 100 against the valve seat 98. In the position shown in FIG. 2, the plunger 94 has been drawn towards the electromagnet by activation of the coil 46 thereby engaging the top of plug 100 and pushing the plug away from the valve seat 98 to allow aerosol spraying liquid to leave the chamber defined by recess 90, 92.

As described, the opening 74 in the tubular portion 72 of the core 68 defines an upper part of an inlet opening. A tubular extension 108 has an upper portion 110 frictionally engaged in the opening 74 and an axial opening 112 extends through the tubular extension 108 defining a lower part of the inlet opening. Aerosol liquid from container 14 passes through opening 112 and opening 74 before entering the chamber defined by recesses 90, 92.

The upper portion 110 of the tubular extension 108 is forced into the core 68 until a shoulder 113 engages the underside of the core for proper location of the tubular extension 108. A lower portion 114 of extension 108 terminates in its lower end in a pair of diametrically opposed axial slots 116 providing access into the inlet opening.

The tubular extension 108 is proportioned such that once the lower housing 16 enters the annular ring 32, the lower end of the tubular extension 108 automatically engages in aerosol valve 62 and depresses a sealing disc 118 which is normally held in sealing engagement against a valve casing 120 by a compression spring 122. A dip tube 124 extends downwardly from valve 62 to the bottom of container 14 for conducting pressurized spraying liquid from the bottom of container 14 to the valve 62. If the apparatus is to be used with the can inverted, there would be no need for the dip tube 124.

The upper portion 110 of the tubular extension 108 defines an internal annular recess 126 for receiving an O-ring 128. A ball 130 is free to move in the inlet opening between O-ring 128 and seal assembly 99 to act as a check valve should the device 10 be removed from the container 14. Upon removing the device 10 from the container 14, the pressure of aerosol liquid above the ball forces the ball into sealing engagement with the O-ring to prevent loss of pressurized aerosol liquid. As soon as the device is again coupled to a container 14, the pressure from the container equalizes that above the ball in the chamber and inlet opening, and the ball is again free to move off the O-ring.

To assemble the device 10, the bobbin 64 together with coil 46 is inserted into the annular recess 66 of the core 68 and sealed in place by the washer 82. The bobbin 64 must be positioned so that the electrical conductors 44 extend through opening 76 in the core 68. Next, the core is dropped into the lower housing 16 and located on the stub 80 with the conductors located in the rectangular recess 42 and axial slot.

The plunger 94 is then positioned in recess 90 with the upper housing inverted, and then the conductors are held in the external slot 49 while housing 16 is screwed into the upper housing 22. Next, the seal assembly 99 is dropped into the upper part 74 of the inlet opening and then the tubular extension 108 is pushed into the opening 74 to complete the assembly. The spray tip 23 is added subsequently depending upon the type of nozzle to be incorporated in the tip. The device is then ready for attachment to a ring 32 on a container 14.

In use, the conductors 44 will be coupled to an electrical control circuit (shown diagrammatically at 132) which periodically couples a dry cell type of battery to the electromagnet 18 for drawing the plunger 94 downwardly to permit spraying liquid to leave the chamber defined by recesses 90, 92 and pass through outlet opening 134 to spray tip 23.

When the electromagnet 18 is not energized, pressure from the aerosol container 14 forces the rod 104 upwardly so that the plug 100 sealingly engages against the valve seat 98 to prevent loss of spraying liquid. As soon as the electromagnet is energized, the plunger 94 moves downwardly against the plug 100 thereby moving the seal assembly 99 downwardly and permitting aerosol liquid to move past the valve seat and out through the tip 23 for a time interval set by the timer circuit. Upon de-energizing the electromagnet, pressure from the aerosol again forces the seal assembly 99 upwardly and the plug 100 seals against the valve seat 98 thereby preventing further loss of aerosol liquid.

The resilient plug 100 can be of any suitable material which will seal against valve seat 98 under the influence of aerosol liquid pressure. However, many sealing materials will swell due to attack by the liquid and the effect of this swelling is simply to move the seal assembly 99 further into opening 74. As a result the swelling has no effect on the operation of the plunger 94 in moving the seal assembly when a pulse of liquid is to be sprayed from tip 23.

Claims

What is claimed as my invention is:

1. A device for periodically dispensing pressurized spraying liquid from an aerosol container, and comprising:

a housing defining a chamber for receiving spraying liquid from the container and further defining an inlet opening providing access to the chamber whereby when the device is coupled to the container, the spraying liquid is free to leave the container and to enter the chamber, and an outlet opening for directing the spraying liquid outwardly from the chamber when the device is actuated; a valve seat coupled to the housing and in communication with the chamber; a seal assembly of non-magnetizable material contained in the inlet opening and free to move axially between a lower position in which liquid is free to pass from the chamber and through the outlet opening, and an upper position in which the seal assembly is in contact with the valve seat such that a predetermined surface area of the seal assembly is covered by the valve seat to seal the chamber, the seal assembly being held in the upper position by a force which comprises the product of the predetermined surface area and the pressure in the aerosol; a plunger of magnetizable material contained in the chamber and free to move axially, the plunger being in contact with the assembly about the predetermined surface area; and an electro magnet coupled to the housing and operable to move the plunger axially downwards thereby moving the seal assembly from the upper position to the lower position for a predetermined time interval to permit spraying liquid to pass from the chamber through the outlet opening.

2. A device as claimed in claim 1 in which the housing comprises a lower housing containing the electro magnet and an upper housing defining the chamber.

3. A device as claimed in claim 2 in which the upper housing includes an internal screw thread and the lower housing includes an external screw thread for combining with the internal screw thread to assemble the upper housing on the lower housing such that the upper housing is engaged against the electro magnet to seal the chamber and prevent loss of aerosol liquid.

4. A device as claimed in claim 1 in which the electro magnet comprises a generally cylindrical axially extending core having an annular recess extending downwardly from its upper face; and an electrically conductive coil housed in the recess, and means sealing the coil in the recess.

5. A device as claimed in claim 4 in which the core defines an axially extending opening defining an upper part of the inlet opening, and in which the device further comprises a tubular extension coupled to the core and having an axial opening defining a lower part of the inlet opening, a lower end of the extension being adapted to engage an aerosol valve in the aerosol container and maintain the aerosol valve in an open position when the device is coupled to the aerosol container.

6. A device as claimed in claim 1 in which the seal assembly comprises: a rod member defining an opening extending downwardly from the upper end of the rod member; and a plug of resilient sealing material set in the opening for sealing by engaging the valve seat.

7. A device as claimed in claim 1 and further comprising valve means coupled to a lower part of the inlet opening for preventing downward flow of the spraying liquid from the chamber when the device is taken off the container.

8. A device as claimed in claim 1 in which the housing comprises a lower housing containing the electro magnet and an upper housing defining the chamber.

9. A device as claimed in claim 8 in which the electro magnet comprises a generally cylindrical axially extending core having an annular recess extending downwardly from its upper face; and an electrically conductive coil housed in the recess, and means sealing the coil in the recess.

10. A device as claimed in claim 1 and further comprising an annular ring having an outer skirt for engagement on the aerosol container and an inner skirt for guiding the housing onto the container and for locating the housing on the aerosol container such that the inlet opening is aligned with an aerosol valve assembly.