Abstract:
A safety closure of an aerosol can comprises an externally screw threaded sleeve having a slit extending along one side thereof and an inwardly extending flange at its lower end. The flange is engageable below an upper peripheral rim of the aerosol can after the sleeve has been temporarily flexed apart along its slit to enable the flange to pass over the rim. An internally screw threaded safety cap threadedly engages over the threaded sleeve and prevents the sleeve from flexing apart along the slit so locking the flange under the rim. The safety cap can only be unscrewed from the sleeve if the cap is additionally pressed firmly downwards. Advantageously the safety cap is of a type used as a childproof closure for medicines.

Description:
FIELD OF THE INVENTION 
     This invention relates to safety closures for aerosol cans, and to aerosol cans provided with such, to prevent or hinder inadvertent or unauthorized operation of the aerosol cans by children. 
     BACKGROUND OF THE INVENTION 
     Aerosol cans are well known for dispensing many products such as, for example, shaving cream, perfume, antiperspirants, insecticides, paint etc. Some of these products are dangerous to children, and some are damaging to clothes, furniture etc. if inadvertently dispensed thereon. 
     Child resistant closures for different types of containers, particularly medicine containers, are well known. Some of these are now inexpensive to manufacture and have obtained credibility with adults. 
     Many attempts have been made over the years to provide child resistant closures for aerosol cans, examples of such being disclosed in U.S. Pat. Nos. 3,349,969; 3,863,814; 4,130,220 and 4,353,483. However, there is still a need for a low cost child resistant closure for an aerosol can which is easy to operate by adults and has credibility with adults. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved safety closure for an aerosol can. 
     A feature by which this is achieved is the employment of a slit sleeve which can be snapped over the conventional peripheral rim of the aerosol can, and then a safety cap screwed onto this sleeve. This has the advantage of enabling medicine type safety caps to be used with aerosol cans, thus providing both credibility and low cost. 
     Accordingly, therefore, there is provided by the present invention a safety closure for an aerosol can having a conventional peripheral rim, comprising a sleeve having top and bottom openings with a slit extending along one side of the sleeve between these openings. The sleeve has externally thereon a screw thread, and has an inwardly extending flange at the bottom defining said bottom opening, whereby the flange can engage below the peripheral rim of the aerosol can after the sleeve has been flexed apart along its slit to enable the flange to pass over the aerosol&#39;s rim. A safety cap having an internal screw thread is screwed onto the sleeve to prevent the sleeve from flexing apart along its slit and so lock the flange under the aerosol&#39;s rim. The safety cap includes means for preventing the cap from being simply unscrewed from the sleeve without performing an additional safety operation. 
     Preferably, the safety cap is of the type used with medicine containers and requiring the cap to be pushed firmly downwards before it will unscrew. 
    
    
     Other objects, features and advantages of the present invention will become more fully apparent from the following detailed description of the preferred embodiment, the appended claims and the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings: 
     FIG. 1 is an elevational view of an aerosol can provided with a safety closure according to the present invention; 
     FIG. 2 is an exploded view of the cap, sleeve and aerosol can of FIG. 1; 
     FIG. 3 is a vertical section of the sleeve of FIG. 2 taken through its slot and showing the peripheral rim of the aerosol can in broken lines; 
     FIG. 4 is an exploded perspective view of the cap of FIGS. 1 and 2; 
     FIG. 5 is a top plan view of the inner member of the cap of FIG. 4; and 
     FIG. 6 is a vertical section of the cap of FIG. 4 when assembled. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The preferred embodiment of the invention is illustrated in FIGS. 1 to 6. 
     FIG. 1 shows a conventional aerosol can 10 having a top peripheral rim 12 (in broken lines) and a dispensing valve member 14 (in broken lines) extending upwardly above the rim 12. A sleeve 16 has a flange 18 (in broken lines) at the bottom engaging below the rim 12. The upper portion of the sleeve 16 has an external screw thread 20 (in broken lines) on which is screwed a safety cap 22. 
     FIG. 2 shows in exploded view the upper portion of the aerosol can 10, the sleeve 16 and the cap 22. The valve member 14 is disposed centrally of the rim 12 and has an orifice 24 through which an aerosol spray is dispensed by depressing or deflecting the valve member 14. The sleeve 16 is of generally cylindrical shape and has a smaller diameter upper portion 26 integrally connected to a larger diameter lower portion 28 by a frusto-conical section 30. The screw thread 20 on the exterior of the upper portion 26 is interrupted by a vertical slit 32 extending down one side of the sleeve 16 from the top opening 34 thereof to the bottom opening 36 thereof, the slit 32 extending continuously through the upper cylindrical portion 26, the frusto-conical section 30 and the lower cylindrical portion 28. The width of the slit 32 is shown exaggerated for clarity. The sleeve is injection molded from thermoplastic material, and is sufficiently resilient to allow the slit 32 to be flexed apart to increase the size of the openings 34, 36, but normally to close the slit so that the longitudinal edges 38 thereof are closely adjacent. Extending radially inwardly from the lower edge of the sleeve is a flange 40. 
     FIG. 3 shows a vertical section of the sleeve 16 taken through the slit 32 and showing one longitudinal slot edge 38. The flange 40 can be seen engaging under the aerosol rim 12 (in broken lines) and defining the bottom opening 36. 
     To assemble the components of FIG. 2, the sleeve 16 is flexed apart along the slit 32 to extend the flange 40 and enable it to pass over the rim 12, whereupon the outward flexing of the sleeve 16 is stopped and the flange 40 snaps under the rim 12 with the longitudinal edges 38 of the sleeve coming back together. While holding the lower portion 28 of the sleeve in one hand, the cap 22 is screwed tightly onto the sleeve 16 with the other hand. This screwing of the cap 22 onto the screw thread 20 ensures that the edges 38 of the slit 32 cannot flex apart so locking the flange 40 under the rim 12 to securely retain the sleeve in position. 
     FIGS. 4, 5 and 6 show further details of the safety cap 22. 
     FIG. 4 shows in exploded view, partly from below, the safety cap 22 having an inner cap 42 and an outer cap 44, both of which can be molded from thermoplastic material. As is shown in the vertical cross sectional view of FIG. 6, the inner cap is rotatably housed inside the outer cap 44 and is retained therein by a lower, radially inwardly extending flange 46 of the outer cap engaging below the lower edge 48 of the inner cap. The inner cap 42 has an internal screw thread 50 for engagement with the external screw thead 20 on the sleeve 16. On the inside of the top 52 of the outer cap are provided a circle of spaced apart, cantilevered resilient tongues 54. Radially outwardly of the tongues 54, and integral with both the top 54 and sidewall 56 of the outer cap 44 are a series of spaced apart stops 58. Around the periphery of the top 60 of the inner cap 42 are a series of castellations 62. On the top 60, inside the castellations 62, are a series of ratchet teeth 64, the arrangement of which is shown in FIG. 5 and the profile of which can be seen in FIG. 6. Each ratchet tooth 64 has a ramp 66 and a vertical side 68. When the outer cap 44 is rotated in the direction of the arrow 70 in FIG. 4, the cantilevered tongues 54 flex and ride over the ramps 66 of the ratchet teeth 64 so that the outer cap rotates relatively to the inner cap 42 and the latter is not unscrewed from the sleeve 16. If the outer cap 44 is rotated in the opposite direction to the arrow 70, the free ends of the cantilevered tongues 54 engage against the vertical sides 68 of the ramps 66 and cause the inner cap to rotate with the outer cap; thus either screwing the inner cap 42 onto the sleeve 16 or, if already screwed-on, further tightening the inner cap on the sleeve 16. However, if the outer cap 44 is firmly pushed down against the inner cap 42 and simultaneously turned in the direction of the arrow 70, the stops 58 engage between the castellations 62 in dog clutch like manner and cause the inner cap to rotate in unison with the outer cap. In this way the safety cap 22 can be unscrewed and removed from the sleeve 16. For further details of the safety cap 22, reference is made to U.S. Pat. No. 3,857,505. 
     In use, the aerosol dispenser is stored with the safety cap 22 securely screwed onto the sleeve 16 which in turn has its lower flange 40 firmly engaged and locked under the rim 12 of the aerosol can. If a child tries to remove the safety cap 22 by simply turning the outer cap 44, then the outer cap will either further tighten the inner cap onto the sleeve 16, further rotation then rotating the sleeve 16 on the aerosol can, or the outer cap will rotate relative to the inner cap with a clicking sound as the tongues 54 flex over the ramps of the ratchet teeth 64. In either case the safety closure 22 will not come off regardless of whether or not the lower portion 28 of the sleeve 16 is gripped in one hand. When a trained person wishes to use the aerosol dispenser, the sleeve 16 is gripped in one hand, the outer cap 44 is gripped in the other hand and simultaneously pushed downwardly and rotated in the direction of the arrow 70 until the cap assembly 22 unscrews and disengages from the sleeve 16. The height of the sleeve, which is higher than the valve member 14, still prevents the aerosol spray being directed. Next, the sleeve is flexed outwardly along its slit 32 to enable the sleeve flange 40 to be disengaged from and moved over the aerosol&#39;s rim 12. The sleeve 16 can then be placed on a surface with the safety cap assembly 22 and the aersol can is now ready for use by directing the orifice 24 at the target to be sprayed and depressing the valve member 14. 
     To again store the aerosol dispenser, the sleeve 16 is first snapped onto the aerosol can and then the safety closure again screwed onto the sleeve 16. 
     It will be appreciated, therefore, that the slit, threaded and flanged sleeve enables known types of child resistant closure caps to be employed with aerosol cans. Such closures are already in mass production so reducing their cost. Further, the adult public is familiar with their mode of operation and has already accepted the credibility of this type of child resistant closure cap. The reduction in diameter of the upper portion 26 of the sleeve enables medicine type closure cap assemblies of normal dimensions for medicine bottles to be readily employed. 
     It will also be appreciated that the necessity of removing the resilient sleeve is a further safety feature. 
     The above described embodiment, of course, is not to be construed as limiting the breadth of the present invention. Modifications, and other alternative constructions, will be apparent which are within the spirit of the invention and scope of the appended claims.