Abstract:
A dust cover for an aerosol container includes a cup-shaped body placed over the dispensing valve of the container in an inverted position. To secure the cover, one or more fixed lugs project inwardly from the bottom edge of the body to engage a rim on the container. The cover is further secured by a release lug. A tab attaches the assurance lug to the body, the tab being permanently deformable to cause the assurance lug to be disengaged from the rim. The cover can then be removed by disengaging the release lug which is moved from its normal position by an actuator.

Description:
FIELD OF THE INVENTION 
     The present invention relates to containers, and, more particularly, to removable dust covers for areosol containers and the like. 
     BACKGROUND OF THE INVENTION 
     Containers from which food and other consumables are dispensed through valves are generally provided with removable dust covers that enclose the valve openings. A variety of arrangements, such as a screw thread and elastically deformed lugs, are commonly known arrangements for holding the cover in place. 
     Aerosol containers of the type that are conventionally used for natural and artificial whipped cream, for example, usually have a rounded top in which the valve is disposed, the valve being surrounded by a rim. The valve can be actuated by displacing a sleave laterally to an off-center position, thereby causing the contents to be expelled through the sleave. To prevent inadvertent actuation of the valve and to maintain the contents in a sanitary condition, a plastic dust cover is placed over the sleave. Lugs on the bottom edge of the cover, of which there are usually two, resiliently engage the rim in a snap-on fashion, securing the cover to the container. 
     It is well known to provide an actuator whereby one of the lugs of the cover can be disengaged from the rim and the cover can be removed. An arrangement of this type is shown in U.S. Pat. No. 3,927,796 to Whitehouse issued on Dec. 23, 1975. 
     It has been found that, with a certain amount of skill and persistence, it is possible to remove a plastic dust cover of this type without leaving any indication that the cover has been tampered with. In fact, the elasticity of the plastic permits such a cover to be deformed sufficiently to disengage the lugs from the rim without using the actuator. It is then possible to force the cover back onto the rim in the original manner, perhaps after dispensing part of the contents of the container. 
     An objective of the present invention is to provide an improved dust cover that cannot be removed from the container without some permanent deformation. Thus, a consumer will know that if a cover is intact and has not been removed, the container carries the same complete contents with which it was originally filled. A further objective is to provide such a cover that does not add significantly to the cost of the article and is conveniently and easily used by the consumer. A still further objective is to provide such a cover that can be readily reused by the consumer after the container has been partially emptied. 
     SUMMARY OF THE INVENTION 
     The above objectives are accomplished, in accordance with the present invention, by a dust cover having a body with the shape of an inverted cup and a plurality of lugs that extend from the body to engage a rim on the top of a container. There is at least one fixed lug, a release lug movable by an actuator when it is desired to remove the cover, and an assurance lug connected to the body by a tab so that it initially engages the rim. The cover can be permanently deformed so that the assurance lug no longer engages the rim, thus permitting the actuator to disengage the release lug in a resilient manner so that the cover can be removed. 
     According to another aspect of the invention, a means is provided for shifting the cover laterally with respect to a force applied to the actuator, thereby causing a fixed lug to become disengaged from the rim. This can be accomplished by a cam surface on the top of the fixed lug, the surface preferably being tapered downwardly from the body sidewall toward the center of the cover. 
     In a preferred arrangement, there are two fixed lugs, one arranged diametrically opposite the release lug while the other is opposite the assurance lug. 
     A particularly advantageous arrangement employs a tab, divided from the body of the cover by slots, that connects the assurance lug to the body. A push-up lever that projects outwardly from the tab can be used to conveniently deform the cover when it is desired to disengage the assurance lug in preparation for removing the cover. Webs connecting the tab to the body are easily broken by the force applied to the lever by the thumb. 
     Other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an aerosol container and dust cover combination constructed in accordance with the present invention; 
     FIG. 2 is a top view showing the cover and a fragmentary portion of the container; 
     FIG. 3 is a side elevation of the cover and part of the container, a portion of the cover being broken away to expose its engagement with the container; 
     FIG. 4 is an enlarged, fragmentary cross sectional view of the container that shows the assurance lug, the adjacent portion of the container being illustrated in phantom lines and the push-up lever being illustrated in phantom lines in its deformed position; 
     FIG. 5 is an enlarged, cross sectional view of a fragmentary portion of the cover, the view being taken along the line 5--5 of FIG. 1; 
     FIG. 6 is an enlarged fragmentary view of a portion of the cover and container, the cover being shown in cross section, as indicated by the line 6--6 of FIG. 3; 
     FIG. 7 is an enlarged fragmentary view of a portion of the cover and container, the view being taken as indicated by the arrow 7 in FIG. 3, the cover being shown in cross section and in the process of being disengaged from the container; and 
     FIG. 8 is a side elevation of the cover and a fragmenting portion of the container, the cover being shown in the process of disengagement from the container. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An exemplary container 10 and a dust cover 12 that embody the present invention, shown in FIGS. 1 through 8, are of a type particularly suitable for dispensing whipped cream and other such toppings. The container 10 has a cylindrical side wall 14 closed by a top 16, with an annular valve receiving member 18 centered in the top. The portion of the top 16 that leads to the receiving member 18 forms a convex shoulder 20 terminating at a circular rim 22 that is formed by folding the outer edge of the receiving member over the top. Thus, the shoulder 20 surrounds the rim 22, which in turn encircles and positions a valve 24 (see FIG. 7). 
     The valve 24 is of well known construction and includes an upwardly projecting flexible plastic sleave 26. To dispense the contents of the container 10, the sleave 26 is simply displaced to a slightly off-center position, allowing the contents to be expelled through the sleave under pressure. 
     The cover 12 is a one-piece molded plastic article. It has a body 28 in the shape of an inverted cup, with a flat-top surface 30, and a sidewall 32 that sweeps outwardly to a circular bottom edge 34 at an open bottom end. Dimentionally, the bottom edge 34 slides over the rim 22 without deforming the cover 12. 
     Securing the cover 12 to the container 10 are four lugs, a release lug 38, an assurance lug 40, and two fixed lugs 42 and 44. The fixed lugs 42 and 44 are opposite the release lug 38 and the assurance lug 40, respectively, the four lugs being spaced apart at 90-degree intervals about the circular bottom edge 34 (as best shown in FIG. 2). Each of the four lugs 38, 40, 42 and 44 is in the form of a narrow lip that extends along an arcuate portion of the edge 34 and projects inwardly a short distance toward the center of the cover 12. The lugs 38, 40 42 and 44 thus fit under the rim 22, securing the cover 12 to the container 10. 
     When the cover 12 is first installed on the container 10, it is heated to permit it to stretch so that the lugs 38, 40, 42 and 44 can snap over the rim 22. Once in place and cooled to room temperature, however, the cover 12 does not have sufficient elasticity and flexibility to permit the lugs 38, 40, 42 and 44 to be disengaged from the rim 22 in a similar manner. 
     The assurance lug 40 and the segment of the bottom edge 34 from which it depends are part of a tab 46 that is separated from the main body 28 of the cover 12 by two parallel slots 48 extending vertically from the bottom edge 34. Preferably the slots 48 are not fully open. Instead, the tab 46 is joined to the adjacent sidewall 22 of the body 28 by a thin plastic web 49 (FIGS. 4, 5 and 6) that is easily broken. 
     Projecting outwardly and horizontally from the bottom of the tab 46, aliged with the bottom edge 34, is a push-up lever 50. Two small buttresses 52 prevent the lever 50 from bending relative to the tab 46. 
     To disengage the assurance lug 40 from the rim 22 in preparation for removing the cover 12, the lever 50 is manually pushed upwardly by the thumb so that the bottom of the tab 46 and the assurance lug are moved away from their initial positions (see FIG. 8). The tab 46 is thus permanently deformed and the assurance lug 40 remains in a disengaged position, as shown in FIG. 8 and in phantom lines in FIG. 4. Accordingly, the push-up lever 50 is used only once during the life of the cover 12. 
     Once the assurance lug 40 and its tab 46 have been deformed, the cover 12 can be removed from the container 10 by depressing an actuator 51 secured to the outside of the bottom edge 34 adjacent the release tab 38. The actuator 51 is a push-down lever with a downwardly projecting, rounded cam surface 52 that extends below the bottom edge 34, and a flat pressure surface 53 on top. 
     Using the thumb, one presses downwardly on the pressure surface 53, causing the actuator 51 to pivot relative to the body 28 upon bending, in a hinge-like manner, where it is secured to the body by a thin strip 54 of plastic (see FIG. 7). The plastic of which the actuator 51 and the body 28 are molded as a single and integral piece is sufficiently flexible and elastic to permit repeated pivotal movement of the actuator 51 without breaking the strip 54. Although some internal breakage and weakening of the plastic may occur, no permanent deformation takes place. 
     As the actuator 51 is depressed, the cam surface 52 rolls and slides on the shoulder 20 of the top 16. The outer end of the actuator 51 moves down while the inner end moves up, thus lifting the adjacent edge 34 and the release lug 38, prying the release lug from its normal position under the rim 22 (see FIGS. 7 and 8). 
     Each of the lugs 38, 40, 42 and 44 has a top cam surface 55 (best shown in FIGS. 2, 3 and 4) that is downwardly inclined from the sidewall 32 toward the center of the cover 12. An upward force applied to any of the lugs, therefore, tends to move the adjacent portion of the sidewall 32 and bottom edge 34 away from the rim 22. This type of interaction between the lugs 38, 40, 42 and 44 and the rim 22 helps to disengage the release lug 38 when the actuator 51 is depressed, but it is particularly significant in a different and more indirect manner with respect to the second fixed lug 44. Since this lug 44 is opposite the disengaged assurance lug 40, it is relatively free to shift the cover 12 laterally. Therefore, at the same time that the direct force applied to the actuator 51 is stretching the cover 12 along an axis extending from the release lug 38 to the first fixed lug 42, the second fixed lug 44 causes the cover 12 to move perpendicularly to that direct force (as indicated by arrows A in FIGS. 2 and 8) until the second fixed lug is disengaged from the rim 22. The cover 12 is then secured only by the first fixed lug 42. 
     As the actuator 51 pivots, the force applied by the thumb to its pressure surface 53 is redirected primarily toward the first fixed lug 42. The cover 12 thus moves away from the actuator 51 and the first fixed lug 42 is disengaged once the release lug 38 passes the top of the rim 22. The cover 12 is then completely released from the container 10 and can be removed. 
     With the assurance lug 40 in its disengaged position, the cover 12 can be readily reinstalled on the container 10. Modest pressure is applied to its top surface 30 causing the three remaining lugs 38, 42 and 44 to snap over the rim 22. Heating is not required. 
     Although the cover 12 will not be held as securely by only three lugs as it was originally by four, it will remain in place for normal use by the consumer. Once the cover 12 is back in place it will be apparent that it had been removed because the tab 46 will be bent outwardly and the webs 49 in the slots 48 will be broken (as last shown in FIG. 8). 
     The use of four lugs, including two fixed lugs 42 and 44, is preferred since it has been found that this arrangement renders it almost impossible to remove the cover 12 without heating so long as the assurance lug 40 remains in its undeformed, engaged position. Three lugs, including only one fixed lug (opposing both the release lug 42 and the assurance lug 44), are less effective and may require the use of a cover 12 having stiffer sidewalls 32. 
     It will be appreciated that the present invention gives the consumer a positive indication that the cover 12 has not been removed from the container 10. It provides a reliable indication, when the tab 46 and the webs 49 are intact and in their original positions, that no portion of the contents of the container 10 has been dispensed. 
     While a particular form of the invention has been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention.