Locking aerosol spray tube

A modified spray cap and extension tube. Positive mechanical interlocking features are added which lock the extension tube to the cap. The extension tube therefore does not fly out of the cap when in use. The modified spray cap is configured so that a conventional diffused spray pattern is still achieved when the modified extension tube is removed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of aerosol spray cans. More specifically, the invention comprises a revised extension tube that locks to the spray cap when in use.

2. Description of the Related Art

Aerosol spray cans tend to deliver a diffused spray. In some applications, such as the precise deposition of lubricants, this diffused pattern is undesirable. Where precise application is needed, an extension tube has customarily been used.

FIG. 1shows a prior art aerosol can10. To dispense its contents, the user pressed down on spray cap12. A diffused spray pattern then issues from orifice16. Extension tube18, which is simply a long hollow piece of plastic, can be inserted into orifice16. In some prior art devices, orifice16is contained within nozzle insert14. Gripping features, such as small ribs or pliable materials, can be included within nozzle insert14. These help frictionally retain the portion of extension tube18that is thrust into orifice16. However, those skilled in the art will know that this frictional retention approach is only marginally effective. The contents of aerosol can10issue forth under considerable pressure. They may also have significant lubricating value. These two factors degrade the prior art devices' ability to retain extension tube18in position. In fact, it is not uncommon for an extension tube18to be launched out of spray cap12like a projectile.

BRIEF SUMMARY OF THE INVENTION

The present invention comprises a modified spray cap and extension tube. Positive mechanical interlocking features are added which lock the extension tube to the cap. The extension tube therefore does not fly out of the cap when in use. The modified spray cap is configured so that a conventional diffused spray pattern is still achieved when the modified extension tube is removed.

REFERENCE NUMERALS IN THE DRAWINGS

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2shows T-cap20and T-tube24. T-cap20generally assumes the same shape as prior art spray cap12. However, a pair of intersecting slots are cut into its upper surface. These are cross slot22and spray slot54. These two slots combine to form a “T” shape, hence the name T-cap20. A modified type of extension tube is configured to mechanically interlock with the two slots. The view shows T-tube24in position to be installed.

FIG. 3shows T-cap20sectioned in half. It is shown just above the position it would normally occupy when installed on aerosol can10. Although the particular method of installing T-cap20on aerosol can10is not significant to the present invention, those skilled in the art will know that one good method of installing such a cap is to press the lower portion of conduit26over delivery tube52.

Delivery tube52remains in aerosol can10. When it is pressed downward, the contents of the can are delivered through the hollow interior of delivery tube52. When T-cap20is installed, the can's contents are delivered through conduit26, eventually emerging through orifice28. Orifice28is actually located in the rear wall of cross slot22, which is designated as first mating surface32inFIG. 3.

The reader will observe that spray slot54is aligned with orifice28. This fact is significant since the device preferably functions well without the use of an extension tube. In other words, the user preferably has the option of a diffused spray available without an extension tube, or a focused spray available with the extension tube. To that end, the side walls of spray slot54preferably diverge somewhat so as not to interfere with the spray pattern when T-tube24is not in use.

FIG. 4shows the portion of T-tube24which is configured to lock into T-cap20in more detail. Locking block30is a rectangular piece which is attached to the hollow tube38. Inlet36is located on second mating surface34. It passes through locking block30to connect with the hollow interior of tube38. The reader will observe by studying the geometry that when T-tube24is pressed into T-cap20, second mating surface34will mate snugly with first mating surface32(assuming that locking block30is properly sized with respect to cross slot22). The height of locking block30is selected so that when its lower surface mates against the lower surface of cross slot22, inlet36will be aligned with orifice28. Tube38will then lie within spray slot54.

Second mating surface34bears against first mating surface32so that when the user presses T-cap20, the contents of aerosol can10will flow from orifice28into inlet36without unwanted leakage. However, for certain low-viscosity solvents, the mating of the two surfaces alone maybe insufficient.FIG. 5shows the addition of gasket insert40to second mating surface34. Gasket insert40is preferably made of a pliable sealing material which helps form a tight seal between orifice28and inlet36. A sealing gasket can also be placed on T-cap20.FIG. 5Bshows an alternate version of T-cap20in which a gasket insert40has been added around orifice28.

FIG. 6shows the completed assembly, with T-tube24mechanically locked to T-cap20. The reader will observe how locking block30rests within cross slot22and how tube38rests within spray slot54. In this configuration, the user may freely employ tube38without fear of it coming loose from T-cap20. The user is also free to use the can with a more conventional diffused spray by simply removing T-tube24. It easily presses into place and it is just as easily removed.

FIG. 7shows other mechanical interlocking means which can be used to lock the extension tube to the cap. Conduit26passes through threaded cap42, bends 90 degrees, and exits at a point on the cap's perimeter. Threaded counterbore44is provided at this point of exit. Threaded tube46is substituted for T-tube24. It has threaded shank48, which features a male thread sized to engage the female thread within threaded counterbore44. Inlet36passes through threaded shank48and connects to the hollow interior of the extension tube. In this embodiment, the user installs the extension tube by threading threaded shank48into threaded counterbore44, and removes it by unthreading threaded shank48from threaded counterbore44. Both components are shown sectioned in half in order to aid visualization.

An alternate embodiment is shown inFIG. 8. Threaded extension50extends from the cap's perimeter at the point where conduit26exits. Threaded extension50features a male thread. An alternate embodiment of threaded tube46is also provided. In the version shown inFIG. 8, threaded shank48features a female thread along the wall of inlet36. This female thread is sized to engage the male thread on threaded extension50. Its operation is the same as for the embodiment shown inFIG. 7; i.e., the user installs and removes the extension tube using the threaded engagement.

FIG. 9A,FIG. 9B,FIG. 10, andFIG. 11show another embodiment of the present invention. An alternative embodiment of threaded extension50and threaded shank48is also provided.FIG. 9Ashows threaded cap42with an alternate embodiment of threaded extension50. Boss56is affixed to threaded cap42around conduit26. Threaded extension50protrudes from boss56at the point where conduit26exits. Threaded extension50features extension tabs58which resemble partial turns of threading on opposite sides of threaded extension50. Extension tabs58feature inclined surface64on the side proximal to boss56.

FIG. 9Billustrates inclined surface64on extension tabs58from a different perspective. Inclined surface64features ridge72which allows extension tabs58to “lock” into place with the spray tube when the two are rotationally engaged.

FIG. 10shows threaded tube46with an alternate embodiment of threaded shank48. Inlet36is sized to receive threaded extension50ofFIG. 9A. Tube tabs60are sized and positioned within inlet36to engage extension tabs58when threaded cap42and threaded tube46are threadedly connected as shown inFIG. 11. Tube tabs60have inclined surface66that mates with inclined surface64when tube tabs60and extension tabs58are rotationally engaged. Inclined surface66is distal to mating surface70so that rotational engagement of tube tabs60and extension tabs58forces mating surface70against mating surface62. Tube tabs60also feature detent68at the peak of inclined surface66, thereby allowing ridge72of extension tabs58to snap into place. Once the ridges72are snapped into the detents68, the threaded tube is held securely in place.

FIG. 11illustrates the attachment of threaded tube46to threaded cap42. To attach threaded tube46and threaded cap42, threaded extension50is inserted into inlet36of threaded shank48so that mating surface70abuts mating surface62. Threaded shank48is then rotated approximately a quarter of a turn in the clockwise direction relative to boss56, thereby engaging extension tabs58with tube tabs60. To release threaded tube46from threaded cap42, threaded shank48is rotated approximately a quarter of a turn in the counterclockwise direction relative to boss56.

The preceding description contains significant detail regarding the novel aspects of the present invention. It is should not be construed, however, as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. As an example, many shapes could be employed for cross slot22, spray slot54and locking block30. They are not limited to the orthogonal walls shown, but could instead be elliptical in shape. Such a variation would not alter the function of the invention. Thus, the scope of the invention should be fixed by the following claims, rather than by the examples given.