Abstract:
An actuator assembly is disclosed which can dispense chemicals, such as insect control ingredients, from an aerosol container. The actuator assembly is mountable to the aerosol container and includes a solid plug that, upon initial activation, will be caused by the pressure of the chemical in the aerosol container to move to an unsealed position. Movement of the plug is retarded by a frictional engagement of the plug with an associated passage/conduit. The device can be manually activated, but is designed so that thereafter it does not need to be manually held open. The consumer has time to leave the room before spraying begins, and does not need to be present in the room before spraying has finished.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Not applicable 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
   Not applicable 
   BACKGROUND OF THE INVENTION 
   The present invention relates to aerosol dispensing devices, and in particular to actuator assemblies that provide a friction-regulated time delay between the initial activation of the devices and the actual release of the aerosol contents to the ambient environment. 
   Aerosol containers dispense a variety of ingredients. One or more chemicals to be dispensed are usually mixed in a solvent and, in any event, typically are mixed with a propellant. Typical propellants are compressed air or other compressed gases, carbon dioxide, a selected hydrocarbon gas, or mixtures of hydrocarbon gases, such as a propane/butane mix. For convenience, materials being dispensed will be referred to herein merely as “chemical(s),” regardless of their chemical nature or intended function. Without limitation, chemicals can include actives such as insect control agents (e.g. a repellent, insecticide, or growth regulator), fragrances, sanitizers, cleaners, waxes or other surface treatments, and/or deodorizers. 
   The active/propellant mixture is stored under pressure in the aerosol container. The mixture is then sprayed out of the container by pushing down or sideways on an activator button at the top of the container that controls a release valve mounted at the top end of the container. The sprayed active may exit in an emulsion state, single phase, multiple phase, and/or be partially gaseous. 
   The aerosol container contents can be released via manual pressure (for as long as such manual pressure is provided). Alternatively, the control valve can be switched to an on position such that essentially the entire contents of the can are automatically dispersed in a single continuous, albeit elongated, burst (e.g. total release foggers), or by intermediate spaced bursts (e.g. automatic dosing systems). 
   U.S. Pat. No. 4,823,986 discloses a system for providing a time delay between the initial activation and the actual release of the contents. This provides the operator time to leave the dispense area to avoid being exposed to the chemicals. This is especially desirable when the active being dispensed is an insecticidal fumigant. See also U.S. Pat. Nos. 2,244,302 and 2,759,768 for other time delay systems. 
   However, such prior art time delay systems often rely on the pressure of the container to burst a thin membrane, or rely on a chemical reaction between the chemicals in the container and a seal which causes a degradation and ultimate rupturing of the seal. The former are difficult to reliably manufacture so as to provide a consistent delay. The latter also have this problem and may provide constraints on the formulation of the chemical. Certain other prior art systems cost so much as to render them impractical, and/or have other deficiencies. 
   Hence, a need remains to provide improved, inexpensive, and reliable time delay systems for such purposes. 
   BRIEF SUMMARY OF THE INVENTION 
   The invention provides an actuator assembly suitable for dispensing a chemical from an aerosol container to ambient environment, with a time delay after (preferably immediately after) initial activation of the actuator assembly. The assembly has a release valve linkable to the aerosol container for controlling the release of the chemical to the environment, an actuator adapted to mount on the aerosol container and be operably connected to the release valve for at least initially activating the release valve, and a time delay system associated with the release valve which comprises a movable solid plug and a wall contacting the plug. By solid plug, we mean a plug that is made of a material with a Shore OO durometer of at least 30. Such a material is harder than gelatinous and thixotropic substances. Preferably, the solid plug is made of a material with a Shore OO durometer of at least 35, at least 40, at least 50, at least 60, at least 70, at least 80, or at least 90. Shore A scale is used to measure harder materials and Shore D scale is used to measure yet even harder materials. For example, 70, 80 and 90 Shore OO durometer correspond approximately to 20, 30 and 50 Shore A durometer, respectively. Therefore, materials with at least 50, at least 60, at least 70, at least 80, or at least 90 Shore A durometer are also suitable materials for making the plug of the present invention. 
   Upon initial activation of the actuator assembly the plug will be caused to move from a sealing position to an unsealing position, with friction between the plug and wall regulating the speed of such movement so as to thereby create the time delay. The pressure in the aerosol container will cause such movement. It is noted that since the solid plug is made of a material sufficiently hard, it will not rupture or substantially deform under the pressure from the aerosol container. 
   In one preferred form the wall is an exterior wall of a conduit end and the plug is in the form of a cap mountable outside and against the end. The plug can be linked by a flexible tether to the conduit. 
   Where the wall is an interior wall of a passage and the plug is in the form of a ball positioned inside the passage to move along the passage, the plug can frictionally engage the wall as it moves along the passage, at least initially in a sealing fashion. Preferred materials are metals and plastics for the wall and ball, with one preferably being made of a soft flexible material and the other being of a more rigid material. 
   The passage can alternatively be provided with two enlarged sections. The first is a enlarged rest area where the ball can reside during storage of the device. The second is a catching area where the ball moves to once it has cleared a sealing portion of the passage. 
   The present invention is most suitable for use with insect fogger products. Upon initial activation the actuator assembly can dispense essentially all the chemical in the container without further outside manual intervention, in a continuous single burst, albeit with an initial time delay. Alternatively, the valve can be used with automatic intermittent sprayers where the dispensing is still essentially total, but takes place with multiple separated bursts. 
   Where the wall is part of a passage, the plug and wall can be configured such that the plug can move from a first position in which the plug blocks dispensing of the chemical from the container to a second position in which the plug is retained by the actuator assembly but does not block dispensing of the chemical from the container. 
   In another aspect the invention provides methods for using such assemblies. 
   In using the present invention a consumer will first manually initiate the actuator system. However, this will not immediately begin spraying. Rather, this will place the can contents in communication with the time delay system. The pressure of the can contents will then begin to act against the plug to begin moving it. However, the plug&#39;s movement will initially be retarded by frictional contact between the plug and an associated wall. While they are in such contact the container will remain sealed off from the ambient environment. Hence, no dispensing will occur for a defined time period. 
   However when the plug has moved sufficiently, sealing contact between the plug and wall will end, permitting container contents to move past the plug to an outlet, thereby dispensing the chemical. The plug is prevented from popping off in an unpredictable manner by providing a tethering system or a catching area. 
   An enlarged rest position can be provided where the plug can be internally positioned with minimal risk that it will be mechanically frozen during storage. In such an assembly the first burst of pressure will drive the plug into a restricted portion of the passage, beginning the time delay. 
   Very low density polyethylene conduits and steel plug balls are a preferred set of materials for practicing the invention. However, numerous materials and combinations of materials should be suitable for use with the invention. By selecting material attributes and length of conduits particular time delays can be designed as desired. See e.g.  FIG. 9  showing the effect of changes in ball diameter when using a one inch long vinyl tube with an inside diameter of 3/16 inch. 
   The time delay system of the present invention is inexpensive to produce, and suitable to be used with a variety of existing total release valves. It has reliable time delay characteristics. 
   The foregoing and other advantages of the invention will become apparent from the following description. In the following description reference is made to the accompanying drawings which form a part thereof, and in which there is shown by way of illustration preferred embodiments of the invention. Such embodiments do not represent the full scope of the invention. Reference should therefore be made to the claims herein for interpreting the scope of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front perspective view of an aerosol can cap embodying the present invention, the view being taken from above and to the right; 
       FIG. 2  is a top plan view of the actuator cap of  FIG. 1 ; 
       FIG. 3  is a bottom plan view of the actuator cap of  FIG. 1 ; 
       FIG. 4  is a cross-sectional view taken along section lines  4 — 4  of  FIG. 2 ; 
       FIG. 4   a  is an enlarged view of the time delay system in  FIG. 4 . 
       FIG. 5  is a cross-sectional view taken along section lines  5 — 5  of  FIG. 2 ; 
       FIGS. 6   a–c  illustrate schematically how features of one embodiment of the present invention work together to provide a timed delay; 
       FIG. 7  is a view similar to  FIG. 4   a , albeit of another embodiment; 
       FIG. 8  is similar to  FIG. 4   a , except of yet another embodiment; and 
       FIG. 9  shows in graph form how the time delay duration can be altered by changing the diameter of the plug. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   U.S. Pat. No. 5,791,524 disclosed a prior art total release actuator and its use with an aerosol container. The disclosure of U.S. Pat. No. 5,791,524, and all other patents referred to herein, are hereby incorporated by reference as if fully set forth herein. 
     FIG. 1  shows a preferred embodiment of an actuator assembly of the present invention, as embodied in an aerosol actuator cap. Assembly  10  is configured to be useful with conventional aerosol containers, such as the one partially shown in phantom lines at  12  in  FIG. 4 . Aerosol container  12  may include the usual cylindrical container wall  14  that is closed at its upper margin by a dome  16 . The joint between the upper margin of the container wall  14  and the dome  16  is the usual container chime  18 . 
   A valve cup  20  is located at the center of the dome  16  and is joined to the dome by a joint in the form of a valve cup rim  22 . A release valve  24  is located at the center of the valve cup  20 . The release valve  24  has an upwardly extending valve stem  26 , through which the contents of the container may be expelled. The valve  24  may be operable by moving the associated valve stem  26  directly downwardly, or by tilting it sideways. 
   The body  28  is adapted to attach to the aerosol container  12 . The actuator body  28  has a peripheral skirt  30 . The lower margin of the peripheral skirt  30  defines a skirt rim  32 . The skirt rim  32  is adapted to fit over and engage the chime  18 . Preferably, the skirt rim  32  actually attaches to the chime  18  by means of undercuts  34  that extend inwardly from the interior surface of the skirt rim. In assembly, the actuator body  28  is forced downwardly onto the chime  18 , the undercuts  34  slipping over the chime to snap under it, fastening the actuator body to the chime. 
   The actuator body  28  also has a central well  36 . The central well  36  preferably has a generally horizontal well floor  38 , as best shown in  FIGS. 1 and 2 . The central well  36  has a trigger port  40 , preferably located in and extending through the well floor  38 . The trigger port  40  has a front end  42 , a back end  44 , and opposed sides  46 . 
   The time delay actuator assembly  10  of the invention includes a longitudinally extended trigger  48 . The trigger  48  has a front end  50 , a back end  52 , sides  54  and a conduit well  110 . The conduit well houses conduit  92  and is formed by side wall  112  extended downwardly from top portion  114  of the trigger  48 . The trigger  48  is attached at one of its front and back ends  50 , 52  to the corresponding front or back end  42 , 44  of the trigger port  40 . This attachment is by means of a hinge  56 , which most conveniently is a living hinge that is unitarily molded with the remaining parts of the time delay actuator assembly  10 . 
   Preferably, the trigger  48  is attached at its front end  50  to the front end  42  of the trigger port  40 , as is shown in the figures, to allow the trigger&#39;s back end  52  to swing downwardly when the trigger is depressed. In any event, the hinge  56  allows the end of the trigger  48  that is remote from the hinge to swing downwardly when the trigger is depressed. The trigger  48  extends from the hinge  56  across the valve stem  26  when the actuator is in place on the aerosol container  12 . This relationship is best shown in  FIG. 4 . 
   The trigger  48  further includes a downwardly open stem socket  58 , as shown in  FIGS. 3 and 4 . The stem socket  58  is adapted to receive the valve stem  26  and is in fluid communication with conduit  92 . The trigger  48 , when moved downwardly, activates the release valve  24  by exerting pressure on the valve stem  26 , which then engages the time delay system  90  to release the content of the container  12  in a time delayed fashion through conduit  92  via valve stem adapter/stem socket  58 . 
   There also may be a latch  62  that preferably is elastically deformable. The latch  62  is attached to one of a side  46  of the trigger port  40  and a side  54  of the trigger  48 . The latch  62  is adapted to engage the other of the side  46  of the trigger port  40  and the side  54  of the trigger  48  when the trigger is in a depressed, valve-activating position to retain the trigger in that position. When in the valve-activating position, the trigger  48  moves the valve stem  26  sufficiently to activate the release valve  24 . 
   It is preferred that the latch  62  is attached to a side  46  of the trigger port  40 , and that before the time delay actuator assembly  10  is activated, the latch  62  extends laterally under the trigger  48 , as is best seen in  FIGS. 3 and 5 . In this embodiment, when the trigger  48  is depressed by a user, the latch  62  first flexes sidewardly, allowing the trigger  48  to pass downwardly beyond the latch to the valve-activating position. When the trigger  48  has reached the valve-activating position, the latch  62  then springs back over the trigger to retain the trigger in the valve-activating position. 
   Preferably, the time delay actuator assembly  10  includes two latches  62 . In the preferred embodiment shown in the figures, one latch  62  extends from each of the opposed sides  46  of the trigger port  40 , although location of the latches on opposed sides  54  of the trigger  48  is also possible. By this means, the two latches  62  retain the trigger  48  under and between the latches when a user has depressed the trigger downwardly between them to the valve-activating position. This arrangement, in combination with other features of the time delay actuator assembly  10  discussed below, leads to a more reliable and trouble-free retention of the trigger  48  when the actuator is used. 
   Preferably the latch  62  is located beneath the level of the well floor  38 . Preferably the trigger  48  includes a push pad  64  on which a user can push to depress the trigger. The push pad  64  may be a surface specially shaped to comfortably receive the user&#39;s finger without slipping off the trigger  48 , as is the push pad shown in the figures. The trigger  48  preferably also includes a downwardly extended drop side  66 . The drop side  66  has an upwardly presented lug  68 , the drop side and lug being best shown in  FIG. 5 . The lug  68  moves beneath and then engages the latch  62  when the trigger  48  is depressed to the valve-activating position. The latch  62  is located sufficiently far beneath the well floor  38  that the trigger  48  reaches its valve-activating position before the finger of a user, pressing on the push pad  64  has the opportunity to contact the latch. 
   Preferably the actuator assembly  10  includes a tear tab  70  that is unitarily molded with the trigger  48  and the actuator body  28 . The tear tab  70  is attached by attachment members  72  to both the end of the trigger  48  that is remote from the hinge  56  and the end of the trigger port  40  remote from the hinge. Thus, when the hinge  56  is located at the front end  42  of the trigger port  40 , the tear tab  70  is located at the back end  44  of the trigger port. 
   The tear tab  70  and attachment members  72  are of a robustness and strength such that the tear tab stabilizes the trigger  48  while the tear tab is in place, reducing the chance of premature activation. However, when a user intentionally and forcibly moves the tear tab  70 , the attachment members  72  break, allowing the tear tab to be removed and leaving the trigger  48  free to be depressed. The tear tab  72  and attachment members  72  are best shown in  FIGS. 2–4 . 
   Preferably the attachment members  72  are shaped so as to break preferentially at a point remote from the tear tab  70  and immediately adjacent to the remaining structure to which they are attached, be it the trigger  48  or the adjacent surface of the trigger port  40 . This arrangement causes the attachment members  72 , when the tear tab  70  is torn away, to break free from the trigger  48  and adjacent surface of the trigger port  40  and remain attached to the tear tab. This arrangement leaves the trigger  48  and trigger port  40  free of any remnant of an attachment member  72  that might otherwise be unsightly or uncomfortable to the finger. 
   Preferably, the peripheral skirt  30  extends upwardly beyond the level of the well floor  38 , and a well wall  74  extends upwardly from the outer margins of the well floor. The well wall  74  is best illustrated in  FIGS. 1 ,  2 , and  4 . The well wall  74  is joined to the upper margin of the peripheral skirt  30  to form a double-walled, hollow bracing structure  76 , best illustrated in  FIG. 4 . The bracing structure  76  extends peripherally around the central well  36 , preferably for at least half and more preferably for at least ¾ of its circumference. Preferably a finger gap  78  is left as an opening in the bracing structure  76  to allow a user easy access to the push pad  64 . The tear tab  70  may be designed to substantially fill the finger gap  78 , further reducing the likelihood of accidental premature activation prior to removal of the tear tab. 
   The bracing structure  76 , well floor  38 , and chime-engaging skirt rim  32  all coact to achieve a rigidity with respect to lateral compression that, taken together with the side location of the latches  62 , is important to the successful operation of the actuator assembly  10 . In a preferred embodiment, a multiplicity of vertical side braces  80  extend upwardly from the skirt rim  32  toward the level of the well floor  38 , the side braces  80  projecting radially from the lower part of the peripheral skirt  30 . Preferably, the side braces  80  rise from a brace floor  82  formed in the skirt  30 , the brace floor preferably resting upon the container chime  18  when the actuator assembly  10  is in place upon the container  12 . The brace floor  82  preferably is substantially horizontal and in any event is less than vertical. The side braces  80  and adjacent portions of the peripheral skirt  30  effectively transmit the rigidity of the chime-stabilized skirt rim  32  to the lower portion of the bracing structure  76 . The interaction of the brace floor  82  and side braces  80 , in conjunction with the remaining adjacent portions of the peripheral skirt  30 , also specifically strengthen the lower part of the actuator body  28  in such a manner as to resist both lateral forces and top loading applied to the actuator body  28 . 
   It will be apparent that the side placement of the latches  62 , the use of two instead of merely one latch, the bracing structure  76 , well floor  38 , chime-engaged skirt rim  32 , and side braces  80  each individually contribute to a reliable engagement of the trigger  48  by the latches, features that are equally effective if the latches are attached to the sides of the trigger  48  and hook under or otherwise engage the well floor or other parts of the body  28  of the actuator assembly  10 . 
   In accordance with the present invention a first embodiment of our time delay system  90  is connected to the valve stem  26  through a valve stem adapter  58  ( FIG. 4 ), which is also configured to serve as the open stem socket as described below. The time delay system  90  has a conduit  92  with an inlet end  94  and an outlet end  96 . The conduit  92  is housed in a conduit well  110  of a trigger  48  as described below. 
   In certain embodiments, conduit  92  and trigger  48  are made of the same material and thus can form a single structural unit. The inlet end  94  is secured to the valve stem adapter  58  and in fluid communication with the release valve  24 . The outlet end  96  is sealed by a cap  98  which can move over the outside wall  122  of the conduit with friction. When the actuator is activated as describe below to open up the release valve  24 , an open passage way is formed from the inside of the container, through valve stem  26  and conduit  92 , to cap  98 . As a result, the propellant/active mix from the inside of the container drives cap  98  to move upward ( FIGS. 6   a–c ) by overcoming the friction between the cap and the outside wall of the conduit. The cap pops open under the pressure and the content of the container is released to the ambient environment. Cap  98  is secured to the outside wall of the conduit through a connection stem  100  so that it does not become free-flying upon being blown off the conduit. 
     FIG. 7  shows another embodiment of the time delay system. A ball shaped plug  102  is employed as the sealing member for conduit  92 , which is configured to have a narrow seal portion  104  where the plug  102  can be placed to seal the conduit and a wide catching portion  106 . The plug can move through the inside wall  120  of a passage of the conduit with friction. Upon activation of the release valve  24 , the pressure from the inside of the container drives the plug to move it upward from the seal portion to the catching portion, at which point the container content bypasses the plug to exit to ambient environment via narrow opens  124  at the outlet end of the conduit. 
   In another preferred embodiment, conduit  92  further has a wide pocket portion  108  where the plug is typically placed ( FIG. 8 ). Upon activation of the release valve  24 , the container pressure essentially immediately pushes the plug into the narrow seal portion of the conduit and further drives the plug to move it from the seal portion to the catching portion after a predetermined period time. Since the plug is not in pressing fit to the inside wall  120  of the conduit while sitting in pocket  108 , this arrangement avoids the potential risk of time delay system malfunction due to mechanical freezing during storage. 
   The above systems can provide for total release of the contents of an aerosol container  12  with only an initial manual intervention. Upon depressing trigger  48  by manual pressure until the latch  62  engages the trigger to retain it in its valve-actuating position, the consumer will then have a defined period to leave before spray begins to exit the device. This can be designed to be 60 seconds or more, but preferably is on the order of 10–30 seconds. Then, the container  12  is left undisturbed until the container&#39;s contents are discharged. 
   The chemical may be dispensed with a single continuous, albeit prolonged, burst. Alternatively, a system such as that shown in U.S. Pat. No. 6,688,492 can be modified to have its outlet converted with a time delay conduit and plug, so as to provide an automatic dispensing valve that iterates between on and off automatically. With such a system multiple segregated bursts could be dispensed, albeit after an initial time delay. 
   The actuator cap is preferably molded from a plastic material. The actuator assembly conduit may be molded from a plastic, and the plug may be a plastic or a metal. Other materials may also be used. 
   The above description has been that of preferred embodiments of the present invention. It will occur to those that practice the art, however, that still other modifications may be made without departing from the spirit and scope of the invention. In order to advise the public of the various embodiments that may fall within the scope of the invention, the following claims are made. 
   INDUSTRIAL APPLICABILITY 
   The present invention provides actuator assemblies useful for dispensing chemicals from an aerosol container in a time-delayed fashion.