US 3472457 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Oct. 14, 1969 T, MOM/0y 3,472,451
AEROSOL TIP AND INSERT ASSEMBLY Filed Jan( 29, 1968 /NVENTOR 5720222515 Wicflwy 1. 1 1
United States Patent 3,472,457 AEROSOL TIP AND INSERT ASSEMBLY Thomas McAvoy, Roselle, Ill., assignor to Valve Corporation of America, a corporation of Delaware Filed Jan. 29, 1968, Ser. No. 701,388 Int. Cl. Bb 1/32, 11/00; F161 37/06 U.S. Cl. 239-337 7 Claims ABSTRACT OF THE DISCLOSURE An aerosol spray tip and discharge assembly is disclosed herein. A tip insert, such as a snorkel tube, is positioned in a discharge socket in the tip and a plurality of discrete, substantially chordal elements projecting from the socket wall into the peripheral wall of the insert are provided. The construction very substantially increases the retentivity of the tip for the insert, yet it does not significantly alter the flow characteristics through the insert nor does it appreciably increase the force required to mate the insert and tip.
BACKGROUND Blowout of inserts positioned in discharge sockets of aerosol tips occurs too frequently. This problem of blowout occurs with small inserts, such as mechanical breakup inserts, as well as with extended inserts such as snorkel tubes. It is to an improved tip construction for substantially reducing the occurrence of blowout with which this invention is concerned.
Snorkel tubes are frequently installed in an aerosol spray tip where spot delivery of the contents of an aerosol container at a distance from the valve is desired. Such a tube is usually a plastic capillary tubing. Because the walls of the tip are comparatively rigid and the tubing because of its circular cross-section also possesses high strength and rigidity, only a limited range of interference fit between the parts is generally permissible to provide the function of retention with ease of assembly. Frequently, obtainable tubes and tips have tolerance ranges that exceed those required for the desired assembly with the result that the tubes either cannot be assembled with the tip or they fall out or are very easily blown out after assembly and use.
In accordance with this invention it has been found that small segmental projections extending from the wall of the tip socket into the socket for engagement with the insert received will greatly enhance the retentivity of the tip insert assembly without noticeably increasing the force required to assemble them, without significantly affecting the desired spray pattern and without additional cold working of the tip and insert.
An interference fit is usually, in this environment, a result of cold working of one or both of the assembled members. As used herein the term is extended to embrace the effective retentiveness of the assmbled members as though they were cold worked, when in fact a substantial portion of the cold working which would otherwise have been necessary is eliminated. Because the cold working is less than that usually required to produce a given interference fit, the assembly force required is also reduced. That also minimizes damage to the tube and tube passageway, minimizing undesired variations in the spray pattern.
A loose or improper fit of an insert, such as a snorkel tube, may permit blow-by or bypass of fluid to be dispensed between the tube and the socket in which it is seated. The instant invention provides for a secure sealing relationship between the tube and tip.
These and other features and advantages of this inice vention will become apparent from the following description and drawings of which:
FIG. 1 is a side elevational view of an aerosol can and spray discharge assembly made in accordance with this invention;
FIG. 2 is an enlarged vertical sectional view of the spray tip of FIG. 1;
FIG. 3 is an enlarged fragmentary view of a portion of FIG. 2 with a snorkel tube in place;
FIG. 4 is an enlarged fragmentary front view taken substantially along line 44 of FIG. 3; and
FIG. 5 is an enlarged fragmentary front view similar to FIG. 4 of a further embodiment of this invention.
Referring now to FIGURE 1, a typical aerosol spray device is shown to include a container 10, a spray tip 11, a valve stem 12, a tip insert, such as a snorkel tube 13, and a mounting cup and valve assembly (not shown). A typical mounting cup and valve assembly is shown in Patent No. 3,074,601, although other assemblies may be used in conjunction with the invention herein disclosed.
Referring now to FIG. 2, spray tip 11 is shown to have an integral stem 12, although tip 11 and stem 12 may be separate assembled members as is well known in the art. Tip 11 defines a top surface 20 by which the valve assembly is actuated when finger pressure is applied thereto in a well known manner. When so actuated the tip defines a fluid flow passageway upwardly through the tip via stem bore 22 which merges internally of the tip in a generally vertical tip bore 24. Near its top, tip bore 24 intersects a lateral fluid flow passage surrounded by a wall 26 which defines a socket 28. Socket 28 terminates at the forward edge of the tip in a discharge opening which opens to the atmosphere. The forwardmost portion of socket 28 may be tapered outwardly as shown at 29 to facilitate insertion of an insert. The rear wardmost portion of socket 28 may be tapered inwardly of the socket (at 32) to assist in retaining and sealingly seating a tubular insert such as snorkel tube 13.
In accordance with this invention and to substantially improve insert retention, the wall of socket 28 defines a plurality of chordal segments 30. These segments are integrally formed with tip 11 and when, as in the embodiment here illustrated, the tip is of plastic, the chordal segments are integrally molded therewith.
Each of the chordal elements 30 as best seen in FIG. 4 is discrete, intersecting the periphery of the socket wall at the ends thereof. As seen in FIG. 4 the Socket is generally circular in transverse cross-section except at those areas where the chordal elements project into the socket. As further seen in FIGS. 2 and 3 the chordal elements are V-shaped in transverse cross-section. The apices of the V-shaped chordal segments lie in a common plane (see FIG. 2) and are equally spaced about the periphery of the socket wall 26 (FIG. 4).
In FIG. 3 a tubular insert such as snorkel tube 13 is positioned within socket 28. Tube 13 is elongate, is generally circular in transverse cross-section and defines a tubular opening 40 extending the entire length of the tube. In the embodiment here illustrated tube 13 is of a material which is somewhat soft and somewhat deformable, such as polyethylene, although its circular cross-section gives it substantial strength and rigidity. Tube 13 is, in this instance, deformable in preference to tip 11 which is of a material such as nylon.
Tip 11 and snorkel tube 13 are proportioned to mate in an interference fit and in the art it is the usual practice to insert snorkel tubes in tip sockets generallly in the manner herein described. However, as stated, the variations in tolerances of the parts too frequently permit blowout in use.
In accordance with this invention the chordal elements 30 which project into the socket 28 also project into the periphery of snorkel tube 13 thereby deformingly engaging the tube wall to increase the interference fit which would otherwise be obtained or to provide an interference fit where it Would not otherwise be obtained because parts of non-matching tolerances have been assembled. To increase the retentiveness of the assembly still further, the socket Wall at 32 tapers inwardly to engage the innermost portion of the tube thereby also to enhance the sealing of the tube with socket wall 26. That is important to avoid bypass of the fluid to be dispensed, i.e., preferential or concurrent passage of fluid between the tube periphery and the socket wall during dispensing through opening 40. The desired sealing effect is enhanced by the presence of chordal elements 30 while they also minimize blowout.
Although increased retentiveness of the tip for the insert is highly desirable a counterbalancing consideration is that minimum assembly or insertion force is desired. In accordance with this invention the insertion force is minimally increased. Indeed those assembling the same tube with tips without chordal elements and those with the chordal elements were unable to distinguish tactually which required more insertion force. Yet retention was very substantially increased.
It is further important that the tube substantially maintain the integrity of the opening therethrough without substantial distortion of it from its uninserted to its inserted condition. Substantial deformation of the tube opening results in spray patterns which vary undesirably from that which the uninserted tubing would provide. Utilization of the invention hereinabove described avoids deleterious distortion of the tube opening.
In pursuance of this invention parts were made and tested. Tips were molded of a hard nylon with four chordal elements V-shaped in cross-section. The elements were positioned equidistantly about the periphery of the socket wall with the apices of the chordal elements lying in a common plane. The maximum height h (FIG. 4) of each of the chordal elements was 0.003 inch and the length about 0.031 inch. Since the diameter of the socket wall at the tube plane of the apices of the chordal elements was 0.083 inch, the distance between opposite chordal elements was 0.077 inch. Any tube having a diameter greater than 0.077 thus would be retained to some extent by the tip, whereas without the chordal elements, tubes less than 0.083 inch in diameter would not be retained.
The presence of the chords reduces the area of the socket in the plane of the apices by slightly less than 5% but changes the periphery and eifective diameter each by only slightly more than 1% to provide an interference fit for tubing that had diameters up to 0.006- inch less than the original recess.
Absent the chordal elements, interference fit would comprehend the eifective change in diameter of the snorkel tube with respect to the tip socket diameter. Where the chordal elements are present it is a combination of that factor with the effect produced by the chords. As stated, the chords change the effective diameter of the socket by very little (hence changing the assembly force only slightly) while the effective interference fit increases dramatically.
Because the interference fit provided by the chords is due to a flattening of the nonrigid circular surface of the tubing rather than the cold-working of the tubing material (as in the usual intereference fit), only limited effort is required for assembly. This then accounts for the fact that increased interference fit is obtained without a noticeable increase in assembly force when chords are added and the assembled tube and tip are otherwise the same.
Generally an interference fit of from about 4% to about 5% Will produce excellent retention and for usual purposes in this art an interference fit of at least about 3% will produce good results. However interference fits in those ranges usually require excessive assembly force. With chordal elements, the assembly force is in the usual permissible range and the effective interference fit is well into the desired range.
A number of tubes were assembled with the tips just described, the tube diameter being 0.0845 $00025. When so assembled they gave an average elfective interference fit of 4.1%. That is to be compared with tiptube assemblies without the chordal elements in which an average interference fit of 1.8% was obtained. It is also to be observed that the chords resulting in a 1% reduction in effective diameter accommodated the full range of tolerances of almost six percent (6%) of the tubing diameter. Assembly force Was not noticeably i11- creased and the spray pattern was not significantly altered. Bypass or blow-by was absent because a good sound seal was provided by the assembly.
When tested at pressures ranging from 50 to 180 pounds of pressure for 4 to 5 seconds, the tube-tip assemblies without the chords blew out 24 of 27 assembled tubes. No blowout of 25 samples of the assembly utilizing the chords occurred. Where three chordal segments (rather than four) were used, in twenty-five samples at the same pressure range none blew out. With two chords six out of twenty-five samples blew out, but then only at pressures of 140 pounds or more, Well in excess of that normally encountered in the aerosol art. In the conventional (no chordal segments) construction 12 samples blew out at less than lbs. and five more at lbs. or less. The two chord construction provided an average effective interference fit of 3.2% and the three chord construction an effective interference fit of 3.7%, each with less than 1% effective increase in diameter of the socket and without a noticeable increase in the force required to assemble the tip and tube.
Referring now to FIG. 5, this is a view similar to FIG. 4 in which only three chordal segments 40 are provided about the wall 42 of a socket 44. This construction is similar in all other respects to that of FIGS. 1 to 4.
Where three or more chordal segments are utilized there is no substantial adverse effect on the flow pattern through the snorkel tube because when equally spaced about the Wall, the chordal segments do not significantly distort the tube bore configuration. There is some dis tortion when only two chordal segments are used and for that reason it may be less desirable to use two.
It will be apparent to those skilled in the art from the disclosure and description herein that constructions other than those illustrated herein may be made without departing from the spirit and scope of this invention.
1. In a spray discharge valve assembly for dispensing fluid under pressure from an associated container, said assembly including a spray tip and a deformable tubular insert mounted therein, said tip having a fluid flow passageway therethrough and providing a wall defining a socket receiving said tubular insert, said tubular insert and the wall of said tip being in an interference fit inwardly of said socket thereby being in sealing engagement with each other about the periphery of said tubular insert, the wall outwardly of the location of said interference fit having a plurality of discrete chordal elements projecting into said socket and also projecting into the peripheral wall of said tubular insert thereby to slightly constrict said tubular insert and to deform the peripheral wall of said tubular insert, thereby to retain said insert within said socket.
2. In a spray discharge valve assembly as set forth in claim 1 wherein said tubular insert is elongated and projects from the tip for dispensing fluid at a point distant from said tip.
3. In a spray discharge valve assembly as set forth in claim 1 wherein the chordal elements number at least three.
4. In a spray discharge valve assembly as set forth in claim 1 wherein the chordal elements number four.
5. In a spray discharge valve assembly as set forth in claim 1 wherein said socket and said tubular insert are generally circular in coss-section, said discrete chordal elements being integrally formed with said tip.
6. In the spray discharge valve assembly of claim 5 wherein the chordal elements are V-shaped in transverse cross-section and the edges of said chordal elements lie in a common plane.
7. In the spray discharge valve assembly of claim 6 wherein said chordal elements reduce the cross-sectional area of the socket in the plane of the chordal element edges by less than about 5%.
References Cited UNITED STATES PATENTS 6 3,085,753 4/1963 Braun et a1. 222-40224 X 3,112,074 11/1963 Green 239-573 X 3,116,856 1/1964 Prussin et al. ZZZ-402.24 3,129,893 4/1964 Green 239-337 X 3,223,293 12/ 1965 Seaquist 222-40224 5 3,228,713 1/1966 Frost 285-238 X FOREIGN PATENTS 97,662 1/ 1964 Denmark. 10 1,194,927 5/1959 France.
286,838 2/1965 Netherlands.
THOMAS F. CALLAGHAN, Primary Examiner