Pressure Powered Aerosol Timer

Abstract

A pressure powered timer for aerosol spray cans operates automatically to periodically spray the contents of the can at desired, predetermined intervals, the pressure within the can being utilized to actuate the timer.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to automatic, pressure actuated timer devices and more particularly to a pressure powered timer for periodically actuating the spray mechanism of an aersol can.

2. Description of the Prior Art

Heretofore it has been difficult to provide a dependable device for periodically causing a spray to issue from an aerosol can or the like. Problems with long period actuation of a can spray mechanism have been very difficult to resolve. Further, an all mechanical, low-cost unit coupled directly to the can top and actuated by the pressure in the can has been difficult to produce because of mechanical defects and operation of these smaller devices. The inventor's issued U.S. Pat. No. 3,589,562, granted June 29, 1971, discloses structure that overcomes many of the problems inherent in the prior art devices. However, the structure disclosed in the aforesaid patent is relatively complex and is therefore costly and liable to malfunction.

SUMMARY OF THE INVENTION

In one aspect of the present invention means are provided for coupling the timing device to the outlet nozzle of the aerosol can so as to maintain the valve in the aerosol can in an open condition. The coupling means is in fluid communication with a first valve in the form of a cylinder having an axially displaceable piston that is movable between valve "open" and "closed" conditions. The interior of the cylinder is in fluid communication with both the atmosphere and with a diaphragm that closes one end of a first cup-shaped chamber filled with a viscous fluid. When the aerosol can discharges, the portion of the contents thereof that is not vented to the atmosphere displaces the diaphragm so as to cause the viscous fluid to flow from the first chamber into a second chamber via a plurality of metering orifices and thereby displace another in the form of a spring loaded piston. When the second piston is displaced axially in one direction, it actuates an over-center toggle mechanism that acts to displace the first piston of the aforementioned cylinder from the "open" condition to the "closed" condition, so as to prevent further discharge of the contents of the aserosol can, either into the atmosphere or into the first chamber.

Accordingly, it is an object of the present invention to provide an improved aerosol can spray timer that is automatically actuated from the normal pressure within the can.

Another object of the present invention is to provide an all mechanical timer of low cost which may be directly coupled to the spray can.

These and other objects, features and advantages of the invention will, in part, become obvious and will, in part, be pointed out with particularity in the following more detailed description of the invention, taken in conjunction with the accompanying drawing, which forms an integral part thereof.

BRIEF DESCRIPTION OF THE DRAWING

In the various figures of the drawing like reference characters designate like parts.

In the drawing:

FIG. 1 is an elevational view illustrating the present invention attached to the outlet nozzle of a conventional aerosol can;

FIG. 2 is a sectional, elevational view of the timer mechanism comprising the present invention;

FIG. 2A is a fragmentary elevational view, in section, illustrating the "closed" condition of one of the pistons shown in FIG. 2;

FIG. 3 is an enlarged, fragmentary, sectional elevational view of one portion of the timer mechanism shown in FIG. 2; and

FIG. 4 is a fragmentary, sectional plan view taken along line 4--4 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIG. 1, the timer mechanism 10 comprising the present invention is directly coupled to an aerosol can A by means of a can 12 and a tube 14 whereby the conventional dispensing valve (not shown) of the aerosol container A is maintained in a normally open position. The cap 12 may be threadably secured to the container A or equivalent; snap-acting retaining means may be employed.

Reference may now be had to FIGS. 2, 3 and 4 for a complete description of the mechanism comprising the timer 10. As shown, there is provided a cylinder, generally designated by the reference character 16, which includes a conduit 18 that is in fluid communication with the tube 14. End wall 20 of the cylinder 16 supports the conduit 18. The inner end of the conduit 18 terminates in an end face 22. A piston 24, defined in part by a resilient pad 26 that is in fluid tight sealing relationship with the interior of said cylinder 16, is positioned so that the pad 26 is in sealing opposition with the end face 22 of the conduit 18. Effectively the pad 26 and the end face 22 comprise a first valve. A piston rod 28 that is secured to the pad 26 to provide for displacement thereof extends outwardly of the cylinder 16 and has a generally triangularly shaped link 30 pivotally connected thereto. Pin 32 provides for the pivotal connection to one corner of the link 30. Another portion of the link 30 is pivotally secured to an extension 34 of the cylinder 16 by means of another pin 36. A connection rod 38 is also pivotally mounted on the link 30 at the third corner thereof. The cylinder 16 is also provided with a cap 37 having an orifice 39 that defines an exhaust outlet 40 for providing communication between the interior of the cylinder 16 and the atmosphere. The cylinder 16 also includes an additional, threaded outlet tube 42 that is similarly in fluid communication with the interior of the cylinder 16 and whose function will be described subsequently.

The cylinder 16 is coupled to a housing, generally designated by the reference character 44, by means of the threaded outlet tube 42. A resilient gasket 46 or the like is interposed between the cylinder 16 and the housing 44 and about the outside surface of the outlet tube 42 to form a seal. There is also formed, within the housing 44, a first chamber 48 that is in opposition to the outlet tube 42 and a resilient diaphragm 50 is interposed between the outlet tube 42 and the chamber 48. As shown in FIG. 2, the chamber 48, which is at least partially filled with a viscous fluid, is formed within a frusto-conical plug 52 that is suitably secured within the housing 44. It will also be seen that the diaphragm 50 is of frusto-conical shape and is positioned between the housing 44 and the plug 52.

A transverse wall 54 that is formed in the plug 52 and which is provided with a plurality of axially extending metering orifices 56 permits fluid communication between the first chamber 48 and a second chamber 58 that is formed within the plug 52. Although only two orifices 56 have been illustrated, more may be used for purposes to be discussed later. As shown in FIG. 2, the lower end of the plug 52 is also frusto-conical and is provided with a second, frusto-conical, resilient diaphragm 60 that is interposed between the lower portion of the plug 52 and the lower portion 44a of the housing 44. The second diaphragm 60 includes a cup-shaped section that extends into the second chamber 58. It should be noted at this time that both diaphragms 50 and 60 are provided with O-ring like rim portions that facilitate their capture between the housing 44 and the plug 52 and between the plug 52 and the lower housing portion 44a, respectively.

A rod 62 is also secured to the transverse wall 54 intermediate the orifices 56 by means of a threaded portion 64. The rod 62 supports a shouldered disc 66 on the upper surface of which is a sealing member in the form of an O-ring 68. Effectively, the O-ring 68 and the surface of the transverse wall 54 against which it abuts define a second valve. Spring means 70 extend between a transverse shoulder of the disc 68 and a flange 72 that is formed on the lower end of the rod 62. As may best be seen in FIG.3, the bore 74 of the disc 66 is slightly larger than the diameter of the rod 62 and defines an annular channel thereabout, the purpose for which will be described hereinafter.

As may also be seen in FIG. 2, the flange 72 rests on one transverse surface of the cup-shaped section of the second diaphragm 60 that is positioned within the second chamber 58. A cup-shaped member 74 is loosely positioned partially within a bore 76 formed in the housing portion 44a and partially within the bore 58, thus being in opposition to the rod 62. The transverse wall of the cup-shaped member 74 bears against the portion of the second diaphragm 60 that is directly opposite the flange 72. A rod 78 is located within and is provided with a transverse upper end flange 80 that bears against the inner surface of the transverse wall of the cup-shaped member 74. A compression spring 82 extends between the flange 80 and a transverse wall surface 84 at the lower end of the housing section 44a in which an opening 86 is formed to permit axial passage of the rod 78.

The lower end of the rod 78 is provided with a crank arm 88 that includes a first leg 88a, middle leg 88b and a third leg 88c. Connected to the third leg 88c of the crank arm 88 is an L-shaped link 90 having a first leg 90a and a second leg 90b. A spring 91 extends between the first leg 88a of the crank arm 88 and the second leg 90b of the L-shaped link 90. The connection rod 38 is also coupled to the second leg 90b of the L-shaped link 90. Adjustable stop means 92 and 94 are secured in the housing 44a in opposition to the first leg 90a of the L-shaped link 90. Alternatively, the stops 90 and 92 may be fixed.

MODE OF OPERATION

When the aerosol can A discharges, the contents thereof will pass through the conduit 18 to the interior of the cylinder 16 and will be vented to the atmosphere through the orifice 39 of the outlet tube 40. A portion of the contents of the aerosol can A will also pass through the outlet tube 42 so as to apply pressure to the upper surface of the first diaphragm 50. The pressurized contents of the aerosol can A that discharges through the outlet tube 42 will distort the transverse wall of first diaphragm 50 and thereby apply a force to the viscous fluid that is contained within the chamber 48. The viscous fluid will be discharged through the metering orifices 56 so as to bear against the transverse face of the disc 66 and thereby exert an axial force sufficient to displace the disc 66. By this action the second chamber 58 will be filled with the viscous fluid. At this time it should be noted that provision of more orifices 56 will reduce the transfer time of the viscous fluid. Alternatively, larger orifices or a less viscous fluid will accomplish the same results.

When the second chamber 58 is sufficiently filled with the viscous fluid, the force thereof will axially displace the second diaphragm 60, the cup-shaped member 74, and the rod 78, thus causing the links 88 and 90 to snap about the axis of the third leg 88c of the link 88. The link 90 will thereby be moved downwardly or in a clockwise direction as shown in FIG. 2 to thereby cause the connecting rod 38 to move downwardly. When this takes place, the link 30 will pivot about the pin 36 to cause the central portion of the pad 26 to move inwardly or to the left as shown in FIG. 2A so that it abuts the end face 22 of the conduit 18 and thereby prevents further discharge of the contents of the aerosol can A either into the atmosphere through the outlet 40 or through the outlet tube 42.

After a predetermined period of time, when discharge of the contents of the aerosol can is not permitted, the viscous fluid in the lower chamber 58 will return to the upper chamber 48 through the annular channel 74 due to the urging of the force of the spring 82 which moves the second diaphragm 60 upwardly and thereby overcomes the weight of the viscous fluid. As the rod 78 moves upwardly, there will once again be an over-center toggle action of the links 88 and 90 that snaps the O-ring 68 against its seat on the undersurface of the transverse wall 54 in order to confine the return flow of the viscous fluid to the orifices 56. It should be noted that the orifices are seized and are in a specific quantity dependent on the type of viscous fluid in use. Thus, the fluid flows through the orifices 56 only when acted on by the pressurized contents of the aerosol can A or by the force of the spring 82. That is, only the viscous fluid will not flow freely in either direction. When forced from chamber 48 into chamber 58, the fluid will stay there until forced back upward so that the cycle can start again.

In one embodiment of this invention the cylinder 16 and the housing sections 44 and 44a were molded of nylon. The resilient pad 26 is preferably made of a synthetic material such as neoprene or the like. Rubber, neoprene or a suitable plastic may be used for the O-ring 68. The choice of materials should take into account resistance to chemicals usually dispensed from aerosol containers.

When the contents of the aerosol can A are pressurized in the order of 30-80 p.s.i., it has been found that three metering orifices 56, each having a 0.005 inches diameter, is very effective when coupled with a channel 74 having about half the cross-sectional area and a viscous fluid such as Dow Silicone 1000. The springs 70, 82 and 91 may exert spring pressures of 1 oz., 30 lbs. and 6 lbs., respectively. With 80 p.s.i. can pressure, a 15-minute cycle and a venting of about 200 mg of freon would be typical.

There has been disclosed heretofore the best embodiments of the invention presently contemplated, and it is to be understood that various changes and modifications may be made by those skilled in the art without departing from the spirit of the invention.

Claims

What is claimed is:

1. A pressure-powered aerosol timer for an aerosol can, said timer comprising:

a. a housing;

b. means for coupling said housing to the can whereby the discharge nozzle thereof is maintained in an open condition;

c. first valve means intermediate said coupling means and the interior of said housing, said first valve including first outlet means in fluid communication with the atmosphere and second outlet means in fluid communication with the interior of said housing, said first valve means being periodically movable between an open condition and a closed condition;

d. a first chamber in said housing, said first chamber including a viscous fluid;

e. a first resilient diaphragm in fluid sealing relationship with said second outlet means and said first chamber whereby the pressurized contents of the aerosol can exerts a force on said first diaphragm with said force being transmitted to the viscous fluid by said first diaphragm when said first valve is open;

f. a second chamber in said housing;

g. orifice means for providing fluid communication between said first and said second chambers;

h. second valve means in said second chamber for periodically opening and closing said orifice means;

i. passageway means in said second valve means providing fluid communication between said second chamber and said first chamber when said first and said second valve means are closed;

j. second diaphragm means for sealing said second valve means in said second chamber; and

k. connecting means responsive to the movement of said second valve means for reversing the condition of said first valve means.

2. The timer in accordance with claim 1 wherein said first valve means comprises fluid inlet means having an end surface, a resilient pad adapted to engage said end surface in the valve closed condition and to be spaced therefrom in the valve open condition and means responsive to said connecting means for displacing said pad between said open and said closed conditions.

3. The timer in accordance with claim 2 wherein said fluid inlet means comprises a conduit in fluid communication with said coupling means, said end surface of said conduit being in spaced relationship and substantially parallel to the plane of said pad.

4. The timer in accordance with claim 2 wherein said second valve means comprises a rod rigidly secured to said housing within said second chamber, a disc slidably mounted on said rod and defining an annular passageway therebetween, resilient means secured to said disc for limiting fluid communication between said first and said second chambers to a path including said passageway and said orifices, when said second valve means is closed, and means for normally biasing said second valve means into the closed condition.

5. The timer in accordance with claim 4 wherein said resilient means is an O-ring.

6. The timer in accordance with claim 4 wherein said connecting means comprises an axially movable rod responsive to the filling of said second chamber with said viscous fluid, means for normally biasing said movable rod in a direction towards the closed condition of said second valve means, an over-center toggle assembly coupled to said movable rod and a connecting arm coupling said over-center toggle assembly to said first valve means.

7. The timer in accordance with claim 6 wherein there is further included means for limiting the movement of said over-center toggle assembly.

8. The timer in accordance with claim 7 wherein said limiting means are adjustable.