CA2259295C - Wick-based liquid emanation system with child-resistant overcap - Google Patents

Abstract

A child-resistant, wick-based liquid emanation system includes a container (30) which is capable of containing liquid and has an opening (36). A wick (50) is partially disposed within the container (30) and extends through the opening (36). A hollow overcap (101) encases the extended portion of the wic k and has a closed, separable tip (100) and an open base (200) attached to cov er the opening. The system is activated by separating the tip from the overcap. A retainer may be provided for obstructing complete removal of the wick from t he container through the overcap after the tip is separated from the overcap. T he retainer can include a shoulder (300) disposed in the overcap (101) between the tip (100) and the base (200) to retain the wick (50) toward the base of the overcap. Alternatively, a protrusion (53) from the wick can engage an inner surface (225) of the overcap or the container. In this case, the overc ap can have a frangible portion facilitating separation of the tip, and the wic k can extend past the frangible portion toward the tip.

Description

WICK-BASEI~ LIQUID EMANATION SYSTEM
WITH CHILD-RESISTANl OVERCAP

Technir~l Field The present invention relates to wick-based liquid emanation systems, and more particularly to (i) a wick-based liquid emanation system having a child-resistant overcap, ~uld (ii) a child-resistant overcap for use with the wick-based liguid emanation system.
Rack~rol-~d Art Wick-based liquid çm~n~tion systems are known in the art for dispersing into the air vaporized particles of any number of liquids. Such systems are oRenused in the home ~Jith liquids varying from insect repellent to air freshener.
- 15 Typically, in such systems, one end of a wick is partially submerged in the liquid to be dispersed. The liquid is contained in any suitable container. The partially submerged portion of the wick absorbs the liquid, some of which dirfuses by capillary or wicking action into the exposed, unsubmcrged portion of the wick.
The exposed portion of the wick is locally heated, often by means of a ring-shaped 2 0 heater which fits o~er the wick. This causes thc liquid which has diff'used h~to the exposed portion of the wick to molecularize or evaporate into the surroundinL~ air.
Continual application of heat to the exposed portion of the wick results in an evaporation/absorption process that continues until the liquid is consumed.
A problem with conventional wick-based liquid emanation systems~ as 2 5 with many products suitable for home use, is the potential that a child will come into contact with the liquid contents of thc system. For exarnple, this can occur when the child tampers with the system or if the system is acciden~ally tipped over, the contents spilled and leR for the child to discover. Many of the liquids utilized with such systems can be harrnful if ingested, and some are harmful if merel~

3 0 contacted. Thercfore, it is desirable to make these systems "child-resistant" and "spill-resistant" to reduce the chance that a child will access the potentially harmful contents of the system.

CA 022~929~ 1998-12-29 WO 98100177 PCT/USg7/11104 An additional concem is the potential that the contents of the system will be prematurely lost through spillage or evaporation. Therefore, it is desirable to provide a sealed sy~;tem in which the contents are retained inside prior to use.In addition, it is desirable that the system provide some indication as to 5 whether it has been opened, alerting users to the potential that some of the contents may have been spilled or otherwise depleted.
One possible approach is to provide a dispenser cap that protects the contents of the system prior to use or that regulates access to the contents during use, or both. Many attempts have been made to develop child-resistant or tamper-10 evident dispenser caps for use with various products.
U.S. Patent No. 5,121,859 ("the '859 patent") to G. Stull, entitled "Non-resealable Dispenser Cap Construction", shows a non-resealable dispenser cap foruse with hand-held dispensers. The cap has an elongated tapered, stepped hollow spout with a discharge orifice. A closurc cap having a transverse c~osure wall is 15 mounted on the spout. The transverse wall engages and closes over the discllarge orifice. With the closure cap so mounted, the transverse closure wall is distorted and biased by its engagement with the wall of the dischargc orifice. Either the closure cap or the spout is forrned with two oppositely-disposed frangible tabs which overlie and are perrnanently attached to the other. Each tab has a zone of20 weakness that can be readily ruptured by rotating either the cap or the spout.
U.S. Paten~ No. 2,930,063 ("the '063 patent") to M. Stull, entitled "Dispensing Cap for Containers", shows a flexible plastic applicator cap for usewith small hand-held containers. The cap has a body adapted to be attached lo the container. A hollow, cylindrical spout is integral with and extends an appreciab]e 2 5 distance from the body. The tip of the spout has a transversely disposed, annular, external end face making an acute angle with the spout's axis, havin~ a discharge orifice surrounded by the surface of the end face and having a stopper forrned with walls of reduced thickness at its base. The walls are integral with the spout and project from the encl face thereof. The cap may bc readily cut or torn. Thereb~, the 30 stopper (at thc reduced walls thereof) is severed from the spout to reveal the CA 022~929~ 1998-12-29 discharge orifice. The stopper has an extremity of reduced diameter for closing the orifice.
U.S. Patent No. 3,083,858 ("the '858 patent") to Biedenstein, entitled "Tear Type Container Closure", shows a container closure which is integrally 5 conntocted to the container by a frangible connection. The closure may be separated from the container by a pull on the closure. This tears the frangible connection, but le~ves a major portion of the material of the frangible connection att~r.h~?cl either to the closure or the container where it will be active as a temporary resealing means between the closure and the container.
U.S. Patent No. 4,757,911 ("the '911 patent") to Larkin et al., entitled "Container and Closure Construction", shows a thin flexible fluid-tight cover ofPVC bonded to a rigid port of a diluent container for use in medicinal applications and which is to be subjected to heat sterilization. The cover includes an outer flange for bonding~ to a complementary surface around the port and a removable 15 section for spanning the port. The removable section includes a central flexible diaphragm and a cylindrical wall. The diaphragm is axially expandable by flexingof an annular convolution. A frangible tear line joins the cylindrical wall to the outer flange. The cylindrical wall is disposed adjacent the outer surfaces of anabutment wall on the port to provide stress relief against rupture of the tcar line 2 0 from stresses generated in the cover during sterilization. A pu]l ring attached to a narrow post is located adjacent the wall for concentrating manual pulling forces to a limited segment of the tear line.
U.S. Patent No. 5,249,695 ("the '695 patent") to Luch et al., entitled "Spout Fitment Closure Plug", shows a spout fitment adapted to be attached to and 2 5 surround a hole in a container, particularly a paperboard carton or other flexible container. The spout fitment has internal threads and an external flange which seals around the hole and is fixed to the container by therrnal means, adhesive or the like. A cap has a top disk from which an externally threaded skirt depends.
The lower edge of the skirt seals against a sealing membrane on the spout.
30 Surrounding the sl~irt is a tamper-evident band attached to the lower edges of . .

CA 022~929~ 1998-12-29 WO 9U00177 rcT/us97/lllw gripping ribs by frangible bridges. The tamper-evident band has a l~\cking dcvice engaging a complementary locking device on the fitment. Thus, the cap cannot be unscrewed without r emoving the tamper-evident band.
U.S. Patenl: No. 5,201,440 ("the '440 patent") to Gross, entitled "Closure 5 with Tarnper-evidenlt Tear-off Panel with a Flow Control Element", shows a container closure which includes a body for mounting on the container. The body defines a dispensin~ orifice. A flow control device, such as a lid, is disposed on the body and moved between positions opening and closing the dispensing orifice.A tamper-indicating member is connected by a first frangible web to the lid. An 10 anchor is connected with a second frangible web to another portion of the tamper-indicating member, and the anchor is retained by the closure body. The tamper-indicating member also includes a graspable pull tab, which can be pulled to completely sever the frar gible webs, permitting the lid to be opcned while providing evidence of tampering with the closure.
A problem with these cap configurations, however, is that they are not particularly suited for use with a liquid emanation system which employs a wick.Nor do they provide "child-resistant" or "spill-resistant" closures for such wick-based liquid ern~n~tion systems.
Additionally, the foregoing configurations do not address a further 2 0 problem which is of ~en encountered with such wick-based liquid em~n~tion systems, namely, the condensation that can accumulate on the heating mechanism and other parts of the system due to excess emanation. If the wick extends a considerable length above the liquid, ern~nZ~tion will occur over the entire length, oRen leading to condensation of excess moisture on the heating device and the 2 5 remainder of the system, which is inconvenient and can be potentially damaging.
One possible solution to this problem would be to limit the length by which the wick extends from the liquid. However, if the wick only extends slightly above the surface of the liquid then it becomes very difficult to heat the wick without heating the liquid reservoir as well. This can lead to additional problems such as direct 3 0 evaporation of the lilquid.

WO g8/00177 PCrlUS97/11104 Accordingly, there is a need for a wick-based liquid emanation system, and for a closure f~r use with a wick-based liquid emanation system, which overcome these and other drawbacks.
There is also a need to provide a closure for use with a wick-based liquid S ern~n~tion system that is par~icularly suited to resist tampering or access by children. (Hereinafter, a wick-based liquid em~n~tion system and closure therefor will collectively be referred to as a "system.") There is a further need for such a system which indicates whether the system has been opened.
There is yet another need in the art for such a system which controls the rate of liquid emanation from the system.
There is ~Ln additional need in the art for such a system which can bc inexpensively manufactured.
Sl-mm~ry Disclosure of Invention The present invention has been madc in consideration of the above-described problems in the prior art.
An object of the present invention is to provide an improved wicl;-t)ased liquid emanation system including a low cost, child resistant closure for such awick-based liquid emanation system.
An additional obiect ofthe invention is to provide such a system wll.ch provides an indication as to whether the system has been opened.
A funher object of the invention is to provide such a system that reduces condensation of product from the wick onto other parts of the system.
Yet another object of the invention is to provide such a system which 2 5 provides for the retention of the wick within the system, to prevent access to the contents thereof.
Accordinl3 to one aspect, the present invention provides a child-resistant, wick-based liquid emanation system including a container capable of containing liquid and having an opening. A wick is partially disposed within the container 3 0 and has an extended portion extending through the opening of the cnntainer A

.. . .. .

CA 022~929~ 1998-12-29 WO 98/00177 PCI'/USg7/11104 hollow overcap encases the extended portion of the wick and has a closed, separab}e tip and an open base. The base is attached to the container to cover the opening. The system is activated by separating the tip from the overcap.
A retain~l ]nay be provided for obstructing complete removal of the wick 5 from the container ti~rough the overcap after the tip is separated from the overcap.
The retainer can include a shoulder disposed in the overcap between the tip and the base for retaining the wick toward the base of the overcap. Alternatively, the retainer can include a protrusion protruding from the wick for engaging at least one of an inner surface c,f the overcap and an inner surface of the container.
~he overcap can have a frangible portion located near its tip facilitating separation of the tip from the overcap, and the wick can extend from within the container past the fTangible portion toward the tip. The wick may be formed withthe protrusion unitary therewith.
According to another aspect of the present invention~ a child-resistant, wick-based liquid ernanation system includes a container capable of containing liquid, a hollow SpOllt protruding from the container and having a closed, scparablc tip, and a wick partially disposed within the container and having an cxtended portion extending into the spout. The system is activated by scparating the tip from the spout.
2 0 According no yet another aspect of the present invention, a child-resistant overcap is provided for use with a wick-based liquid emAn~tion system, the system including (i) a container having an opening and (ii) a wick partially disposed within the container and having an extended portion extending through the container opening. The overcap includes a closed, separable tip, an open basc 2 5 ~ .ch~ble to the container to covcr the container opening, and a shoulder disposed between the tip and the base. The overcap encases the extended portion of the wick when the base ;is attached to the container, and the shoulder retains the wick toward the base of the overcap. The system is activated by separating the tip from the overcap.

CA 022~929~ 1998-12-29 WO 98/OOlM Pcr/US97tlll04 According to still another aspect of the present invention, a child-resistant overcap is provided for use with a wick-based liquid emanation system including (i) a container having an opening and (ii) a wick partially disposed within the container and having an extended portion extending through the container opening.
5 The overcap inclu,~es a closed, separable tip and an open base which is attachable to the container to cover the container opening. The overcap encases the extended portion of the wiclc when the base is attached to the container. A retainer is provided for obstnLIcting complete removal of the wick from the container through the overcap after the tip is separated from the overcap.
This brief summary of the invention has been provided so that the nature of the invention may be generally understood. ~lowever~ this summary should not be construed to limit the invention.
The fore~;oing and other objects, aspects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings.
]"R~FF DF.SC}? IPTION OF THF. D~AW1~1GS
Figure I is a partial cross-sectional view, in elevation, of a first pref'erred embodiment of the wick-based emanation system with child-resistant overcap of the present invention.
2 O Figure 2~ is a partial cross-sectional v iew, in eleva~ion, of a second preferred embodiment of the wick-based emanation system with child-resislan~
overcap of the present invention.
Figure 2E, is a plan view of the second preferred embodiment of the present invention.
Figure 3A. is an exploded cross-sectional view, in elevation, of a third preferred embodirnent of the present invention.
Figure 3B is a cross-sectional view, in elevation, of the embodiment shown in Figure 3A, as assembled.
Figure 4A. is an exploded, cross-sectional view, in elevation, of a fourth 3 O pref'erred embodimient of the present invention.

Figure 4B is a cross-sectional view, in elevation, of the embodiment shown in Figure 4A., as assemb1ed.
Like reference numerals have been used for like or similar elements throughout the vievrs.
Modes of C: ~rryi~ out the Inve~tion Figure 1 shows a partial cross-sectional view, in elevation, of a first preferred embodiment of the wick-based liquid emanation system 201 of the present invention. l,iquid ern~n~tion system 201 includes a container 30 for containing a liquid l not shown) to be dispersed, a wick 50 partially disposed in container 30 and an overcap 101 secured to container 30. These features will be discussed in more detail below.
One end (not shown) of the wick 50 is partially submerged in the ]iquid to be emanated. The shape of the container 30 is not an essential feature of the invention. Therefore, the portion ofthe container 30 containing the liquid is not shown in detail in the drawin~. The other end of wick 50 extends out throuL~h anopening 36 in the container 30. In this embodiment, the container 30 has a neck 35 through which the opening 36 is disposed.
In this em~odiment, the overcap 101 is shown having a generally circular cross section, and is secured to the neck 35 of the container 30, as will be discussed 2 0 in more detail below. Of course, the overcap 101 need not ~e generally circular in cross section. Rather, other geometrical shapes can be used as desired.
Nevertheless, forthe purposes of conciseness and clarity, the overcap 10l will be described as being circular in cross section, with reference to such features as its "diameter" and "circumference."
2 5 The overcap 101 encases a portion of the wick 50 which extends through the opening 36. The tip 100 ofthe overcap 101 is closed. The base 200 ofthe overcap 101 is secured to the container neck 35. Between the tip 100 and the base 200, wall 150 of the overcap 101 defines a cavity 155 which preferably, but not necessarily. conforms closely to the shape and size of the wick 50, so that it closely 3 0 encases the wick 50.

.

WO 98100177 PCI'IUS97/11104 In this ernbodiment, overcap 101 includes a shoulder 300 provided near the tip 100. The shoulder 300 defines a reduction in the diameter of the cavity 155.
A transverse wall 310 extends partially inward from the wall 150 to effect this reduction in ~ Tnet~.r. This transverse wall 310 acts as a barrier~ for reasons that 5 will be made apparent later, against movement of the wick S0 by some external force past the shoulder 300 toward the tip 100.
Extending from the tip 100 to the transverse wall 310 is a skirt 110. The skirt 110 is shown as having a larger rli~m~ter adjacent the shoulder 300 than it does adjacent the l;ip 100. However, the skirt 110 can increase, decrease, or remain 1 0 constant in diameter from the shoulder 300 to the tip 100 depending on the relative dimensions of the tip 100 and the shoulder 300. Additionally, the skirt 110 and transverse wall 310 need not be separate elernents, but can be combined. If this is the case~ the com~lination skirtltransverse wall should decrease in diameter as it approaches the tip 100 in order to provide the barrier past which the wick 50 1 5 cannot be moved without considerable effort. Alternately, the transverse wall 310 can be provided as a cantilever-like barrier, and the skirt I 10 can extend froln the outer perimeter 311 of the transverse wall 310. In this case. the transverse wali 310 can be formed in any number of shapes to effect a localized reduction in diameter of the cavity 155 past which the wick 50 cannot be moved without considerable 2 0 effort.
In the embodiment of Figure I, the base 200 of overcap 101 is provided with an inner flang~e 220 and an outer flange 240 for securing the overcap 101 to the container 30. The inner flange 220 engages inner wall 33 of the container neck 35. The outer flange 240 engages outer wall 34 of the container neck 35.
2 5 Together, the inner and outer flanges 220, 240 define a seat 230 into which mouth 37 of the container 30 fits. In this embodiment, the mouth 37 and seat 230 can be welded, fused, or othen,vise penn~ner tly bonded together to provide a sealed engagement. While it is ~"efel,ed that the base 200 be fixed in engagemellt to the neck 35, this particular means of engagement is not critical to the invention. The WO 98100177 PCTtUS97tlllW

base 200 and neck ~ 5 can be engaged by any of a number of means, some of which will be discussed in more detail later.
In this embodiment, the overcap 101 seals the wick 50 and liquid contents of the system 201 within the container 30. In order to activate the system 201, i.e., 5 permit dispersal of the liquid into the su~ounding atrnosphere, the tip 100 isseparated from the overcap 101. For example, the tip 100 can be separated by cutting through the skirt 110. This feature of the invention ~the separation of the tip 100) can be accomplished in other ways. For example~ a groove ~not shown) can be provided in the skirt 1 10 to create a localized weakness in the overcap 101 .
In that case, the tip ]l 10 can be removed by tearing the overcap 101 at this weakened groove. Alternatively, the tip 100 can be a separate piece, adhesively affixed to close the e nd ofthe overcap 101. In that case, the system 201 would be activated by peeling off or otherwise removing the tip 100 from the overcap l 01.
These and other equivalent ways to secure the tip 100 to overcap 101 can be utilized within the concepts of the present invention.
In any ofth.ese embodiments, once the tip 100 is removed, an openillg is created in the overcalp 101 through which the distal end 51 of the wick 50 is exposed. Now, however, the shoulder 300 of overcap 101 acts as a retainer against removal of the wick 50. It is preferred that the wick 50 not pass by the sh~ulder 300 toward the newly-formed opening in the o~ercap 1()1.
Once the tip 100 has been separated, heat can be applied to the pOI liOIl of the wick 50 within the overcap 101 by means of a localized heat source (no~
shown), preferably but not necessarily in the form of a ring-shaped heating element (not shown) which encircles the overcap 101. Wick 50 disperscs liquid to tl~e 2 5 surrounding atmospllere, which in turn allows additional liquid to enter the wick from the container.
In addition to securing the wick 50, the overcap 101 acts to reduce the deliver,v rate of mole:cularizcd liquid into the air. By perrnitting emanation to oecur primarily through the distal end 51 of the wick 50~ instead of throughout the entire WO 9U00177 rCT/US97/1 length of wick 50, liquid residue is less likely to condense on the heating mechanism and other internal surfaces of the system 20.
In some cases, it may be desirable to provide for a greater rate of em~n~ion. An alternate embodiment of the wick-based liquid em~n~tion system 5 with child-resistant overcap of the present invention is shown in Figures 2A and 2B. Reference sh~uld be made to the discussion of Figure 1 above for a detailed description of like elements from the first embodiment. A major difference between the secorld embodiment and the first embodiment is that, in the second embodiment, the wick 50 extends from overcap 102 once the tip l 00 is removed.
In the second embodiment, it is preferred that the tip 100 not bc separated from the overcap 102 by cutting, because the wick 50 could be cut as well.
Therefore~ in this embodiment, wall l 50 is provided with a frangible portion 400, in this case defined by a pair of substantially parallel, V-shaped grooves 420 and 440. It is preferreld that the distal end S I of the wiclc 50 extend beyond this frangible portion 400 toward the tip 100.
In this embodiment, as in the previous one, system 202 is activated by removal of the tip l 00. In this case, the removal is accomplished by tearing the tip 100 off of the overcap l 02 at the frangible portion 400. The wick 50 will extend out from the overcap 102, which is now open at the frangible portion 400. to allow 2 0 greater wicking action to occur due to the additional wick exposure. In order to facilitate the removal of the tip 100, a tab 500 may be provided, extending from the wall 150 between the grooves 420, 440. This allows the user to grasp the tab 500and pull to effect the tearing of the frangible portion 400. Tab 500, attached to wall 150, is shown in more detail in Figure 2B.
2 5 In this embo~lim~nt, because there is no shoulder to act as a retainer~ it may be desired to provide an alternate form of retainer for obstructing the removal of the wick 50 through the overcap 102 once the tip 100 is separated. This wouldreduce the likelihood that a child could remove the wick 50 and access the liquid.
It would also minimli7~ the amount of spillage that would occur should the system 3 o 202 be accidentally tipped. This can be done by several means. If the wick 50 is straight and of conventional construction, i.e., bonded polyester, cellulose, or the like, an external mechanical retainer can be employed. For example, a pin (not shown) can be inserl:ed through the wick 50, so that it protrudes from the wick 50 and the combination cannot fit through the overcap 102 or the container opening 36. Alternatively, a clamping collar 53 or the like can be provided, as shown, as a protrusion for the same purpose. Clarnping collar 53 can be secured to wicli 50 in any desired manner.
Also, as an alternative to the arrangement discussed above, this embodiment and the ones ~1iecllcsed below employ various "stake-on" or "snap-fit"
1 0 methods of eng~ging the overcap 102 and the container 30. The method used in this embodiment will now be discussed.
Outer flange 240 of base 200 is provided with an inwardly-depending pawl 248. This pawl 24~ engages with container lip 38 which protrudes from the container neck 35. Preferably the lip 38 and pawl 248 extend fully around ~he 1 5 perimeters of the neck 35 and outer flange 240, respectively. I'he lip 38 and the pawl 248 are respectively provided with a tapered leading edgc 39, 249 and a llat trailing edge 37, 247. Therefore, when the overcap 102 is brought into en~agement with the container 3(), the leading edge 39 of the lip 38 initially engages the leading edge 249 of the pawl 248. This engagement of these tapered surfaces 39, 249 2 0 causes the outer flange 240 to deforrn outwardly, allowing the pawl 248 to slip past the lip 38. The pawl 248 snaps behind the lip 38, so that the trailing edge 37 of the lip 38 engages the trailing edge 247 of the pawl 248.
In another embodiment, shown in the exploded cross-sectional view of Figure 3A, in order to securely retain the wick 50 while facilitating the loading of' the wick 50 through the container opening 36, a flexible collar 55 is provided.
Collar 55 can have flexible wings 57 which angle upward and can be flexed upward against the wick 50. Thus, upon insertion, the wings 57 will elasticall~
collapse against the wick 50 to perrnit the wick 50 and collar 55 to be inser~edthrough the container opening 36 into the container 30. Once entirely througll the 3 0 container opening 36, the wings 57 will open and engage the inside of cither the container 30 or the overcap 103, as shown in Figure 3B~ obstructing the removal of the wick 50. To in.crease the integrity of this design, a circumferential groove 58 can be cut out of the wick 50 to provide a seat for the collar 55. Collar 55 can be made of flexible mletal or plastic, for example, to facilitate in~t~llation. Figure 3B
also shows an optional recess 303 in the container 30 for receiving wick 50.
Figures 3A and 3B illustrate an additional feature that can be provided with any of the embo-liment.c. In these figures, the tip 100 (see Figures 1, 2A and 2B) has already been removed from the overcap 103. Instead of merely leaving behind an opening through which the wick 50 extends, in this embodiment a pervious cage 120 closely encases the extended portion ofthe wick 50. This assists in ret~inin~ the wick 50. When cage 120 is ~ltili7Prl it is preferred, for sim~licity of construction, that the tip 100 of the overcap 103 be a separate piece adhesively affixed to or sealecl over the cage 120, so that it can be peeled or otherwise readily removed from the overcap 10 to activate the system 20. The tip 100 alternativelycould be integrally formed with the overcap 103, so that the tip 100 is a separate layer which encases the cage 120, and the overcap 103 can be providcd with a frangible portion alt which the tip 100 can be separated therefrom.
This embodiment employs a variation of the earlier-described "stake-on"
method of engagen~ent between the overcap 103 and the container 30. Similar to 2 0 the arrangement discussed with respect to the embodiment shown in Fi~ure ~A~ the outer flan~e 240 oi the overcap 103 is provided with an inwardly-depending pawl 248. The container 30 is provided with a corresponding lip 38, which engages thepawl 248 in a similar manner to the earlier embodiment. In this embodiment, however, the inner flange 220 does not depend downwardly from the base 200.
2 5 Instead, the inner flange 220 extends upwardly from a spacer ring 235, which extends out from the base 200. By spacing the inner flange 220 from the base 200, the overcap 103 can sit within the container neck 35, as shown in Figure 3B. This arrangement perrnits the cont~in~r neck 35 to have a substantially larger cross section than the wi,ck 50, making it much easicr to insert the wick 50 and ovcrcap 3 0 103 into the contairler neck 50.

CA 02259295 l998-l2-29 WO 98100177 P~~ ,g711110~ -ln yet another embodiment, shown in the exploded cross-sectionat view of Figure 4A, a protrusion or collar 53 may be formed integrally with a wick 50 itself.
By way of example, this can be accomplished by molding a wick 50 with an integral collar 53.
In the present invention, the plefe.led method of molding the wick 50 is sintering. In this method, a suitable powdered plastic, such as ultra-high molecular weight polyethylene or polypropylene, is lightly packed into a mold. This packing can be accomplished by light pressure or vibration or any other suitable means.
The packed mold is then heated to a temperature which is sufficient to allow the10 plastic to bond togel:her, but not suf~lcient to li~uefy the plastic to such an extent that it can flow. Thiis results in a solid piece which is porous and therefore wicks liquid. A wick of such construction can be molded into a variety of shapes. ln addition, an overcap 10 for use with such a wick can be formed to have a shape conforming thereto.
Referring back to Figure 4A, in this embodiment, overcap 104 is provided with an inner step 225. As can be seen in Figure 4B, the step 225 engages the collar 53 when syste:m 204 is assembled, ret~ining the wick 50 in the container 30.
It should be noted that, using this method, the wick 50 alternatively could be molded with a groove for use as a seat for a separate winged collar such as 2 0 described above with respect to the Figures 3A and 3B.
A variation of the embodiments shown in Figures 2A through 4B is one in which only a single flange is provided, which engages the container neck 35. This single flange may snugly fit either over or within the container neck 35. Further, although a "stake-on" arrangement has been shown in the preceding embodiments, 2 5 other methods may be utilized to secure a respective overcap to container 30. For example, frictional securement, various mechanical interlocking arrangements~
chemical bonding, or heat welding may be utilized. It is preferred, however, that the engagement be such that the respective overcap cannot be removed without considerable force or effort.

WO g8/00177 PCT/USg7/11104 Of course, it is not a nPcessAry feature of the invention that the container 30 have a neck 35. If no neck is provided, a respective overcap can be affixed directly to the mo uth 37 of the opening 36 of container 30 in a manner simi lar to those described above.
It is also possible that an overcap can be integrally forrned with the container 30. If this is the case, the containerlovercap is formed with a temporary orifice for filling ~md loading. The liquid is added, and the wick is loaded into place. At this pOi]lt, the orifice is sealed, closing the system. Such a system could be configured according to any of the embodiments described above.
ln each of the embodiment.s discussed above, for cost ef~ectiveness, a respective overcap is preferably formed by injection molding. In general, an overcap is preferably made of a thermoplastic or other material which has a highenough heat index to withstand heating and is impervious to chemical attack fromthe liquid used in the em~nAtion system. In the case of a snap-fit or similar engagement mech~nism, the material should provide sufficient flexibility to permit engagement. The particular application of the system will dictate which specificmaterial is best.
If the sysLem is being used to em~nRte an air freshener, then the wick 50 will need to be exposed to temperatures on the order of approximately 60~C.
2 0 Polyethylene is particularly well-suited for this, especially with respect to ~hc embodiments in which a tip is torn from an overcap at a localized weakness because this therrnoplastic has less tensile strength and tears more easily than most.
On the other hand. materials such as nylon, polypropylene or other thermoplastics with higher heat indexes will be better suited for higher-temperature 2 5 applications. For e xample, if the system is being used to emAnAte an insectrepellant, temperalures closer to or excee~in~ 120~C may be necessary for properwicking.

~ r ln~ustri~l ~plicability The wick-based liquid em~n~tion system and overcap of the present invention can be use d wherever it is desired to molecularize and disperse a liquid into the atmosphere via a wicking mec~ni~m. For instance, the system and 5 overcap can be used in such varied applications as dispersal of insect repellent or air ~ieshel-el, for ex~nple, into the air.

Claims

WHAT I CLAIM IS:
1. A child-resistant wick-based liquid emanation system comprising:
a container capable of containing liquid, said container having an opening;
a wick partially disposed within said container and having an extended portion extending through the opening of said container; and a hollow overcap encasing the extended portion of said wick, said overcap having a closed, separable tip and an open base, the base being attached to said container to cover the opening, wherein said system is activated by separating the tip from said overcap.
2. The system of claim 1, further comprising a retainer for obstructing complete removal of said wick from said container through said overcap after thetip is separated from said overcap.
3. The system of claim 2, wherein the retainer comprises a shoulder disposedin said overcap between the tip and the base for retaining said wick toward the base of said overcap.
4. The system of claim 2, wherein said retainer comprises a protrusion protruding from said wick for engaging at least one of an inner surface of said overcap and an inner surface of said container.
5. The system of claim 4, wherein said overcap has a frangible portion located near the tip, the frangible portion facilitating separation of the tip from said overcap.
6. The system of claim 5, wherein said wick extends from within said container past the frangible portion toward the tip.
7. The system of claim 6, wherein:
said container has a neck through which the opening is disposed, and said overcap has a flange depending from the base which engages the neck of said container.

8. The system of claim 7, wherein the neck of said container and the flange of said overcap have corresponding protrusions which interact to lock the base of said overcap to said container.
9. The system of claim 4, wherein said wick is formed with said protrusion unitary therewith.
10. The system of claim 9, wherein:
said container has a neck through which the opening is disposed, and said overcap has a flange depending from the base which engages the neck of said container.
11. The system of claim 10, wherein the neck of said container and the flange of said overcap have corresponding protrusions which interact to lock the base of said overcap to said container.
12. A child-resistant, wick-based liquid emanation system comprising:
a container capable of containing liquid;
a hollow spout projecting from said container, said spout having a closed, separable tip; and a wick partially disposed within said container and having an extended portion extending into said spout, wherein said system is activated by separating said tip from said spout.
13. The system of claim 12, further comprising a retainer for obstructing complete removal of said wick from said container through said spout after the tip is separated from said spout.
14. The system of claim 13, wherein the retainer comprises a shoulder disposed in said spout between the tip and said container, the shoulder retaining said wick toward said container.
15. The system of claim 13, wherein the retainer comprises a protrusion protruding from said wick for engaging at least one of an inner surface of said spout and an inner surface of said container.

16. The system of claim 15, wherein said spout has a frangible portion located near said tip, said frangible portion facilitating separation of said tip from said spout.
17. The system of claim 16, wherein said wick extends from within said container past said frangible portion toward said tip.
18. The system of claim 15, wherein said wick is formed with said protrusion unitary therewith.
19. The system of claim 13, wherein said wick has a circumferential groove on a portion thereof which is disposed within said container, and wherein said retainer comprises:
a collar seated in the groove of said wick; and a wing extending from said collar for engaging at least one of an inner surface of said spout and an inner surface of said container.
20. The system of claim 19, wherein said wing is elastically foldable against said wick toward the extended portion of said wick to facilitate insertion into said container of the portion of said wick at which said wing extends from said collar.
21. A child-resistant overcap for use with a wick-based liquid emanation system, the system including (i) a container having an opening and (ii) a wick partially disposed within the container and having an extended portion extendingthrough the container opening, said overcap comprising:
a closed, separable tip;
an open base being attachable to the container to cover the container opening, wherein said overcap encases the extended portion of the wick when said base is attached over the container opening; and a retainer for obstructing complete removal of the wick from the container through said overcap after said tip is separated from said overcap.
22. The overcap of claim 21, wherein said retainer comprises a pervious cage, and said tip is removably attached to said cage.

23. The overcap of claim 21, wherein the wick has a protrusion, and said retainer comprises an inner surface of said overcap for engaging the protrusion.24. The overcap of claim 23, wherein said overcap has a frangible portion located near said tip, said frangible portion facilitating separation of said tip from said overcap.
25. The overcap of claim 24, wherein the container has a neck through which the opening is disposed, and said base has a flange which is attachable to said neck.
26. The overcap of claim 25, wherein said flange and the container neck have corresponding protrusions which interact to lock said base to the container.
27. The overcap of claim 21, wherein said retainer comprises a shoulder, disposed between said tip and said base, which retains the wick toward said base.
28. The overcap of claim 27, wherein the container has a neck through which the opening is disposed, and said base has a flange which is attachable to said neck.
29. The overcap of claim 28, wherein said flange and the container neck have corresponding protrusions which interact to lock said base to the container.