US2921343A - Method of producing a component of a liquid dispenser - Google Patents

Description

G. V. MUMFORD Jan. 19, 1960 HOD OF PRODUCING A COMPONENT OF A LIQUID Filed May 15. 1957 V INVENTOR GEORGEY MunroRn Jan. 19, 1960 G. v. MUMFORD 3,921,343

METHOD OF PRODUCING A COMPONENT OF A LIQUID DISPENSER Filed May 13, 1957 2 Sheets-Sheet 2 INVENTOR GEORGE MUMEOKD Unite ttes lVIETHOD F PRODUCING A (IOMPONENT OF A LIQUID DISPENSER George V. Mumford, Toledo, Ohio, assignor to Owenslllinois Glass Company, a corporation of ()hio The present invention is an improved method for producing dispensing openings in a component of a liquid dispenser or applicator of the type presently utilized in the application of liquid deodorants, etc. to portions of the human body. Examples of the type of applicator involved are disclosed in patents, No. 2,700,784 issued February 1, 1955 to R. F. De Brock and No. 2,749,566 issued June 12, 1956 to R. H. Thomas. In both of these patented devices, a ball or marble is mounted in a thermoplastic holder or fitment which is separably attached to a container for the liquid deodorant or other material.

My invention is directly related to a liquid applicator or dispenser in which the applicator ball is mounted in a holder formed of polyethylene or some similar thermoplastic material and has an internal annular ball seat and immediately therebeneath an aperatured web which functions as a ball unseating means preparatory and during use of the applicator. It is imperative that this web be capable of sufiicient axial flexing under certain conditions to permit effective sealing contact between the ball and seat and at other times capable of returning to its initial position to thereby unseat the ball and permit flow of the liquid deodorant, for example, onto the ball and, additionally, allow the ball to rotate and transfer the liquid to another surface.

According to one presently used method of producing a holder of the above character, the dispensing openings are formed in the web simultaneously with molding of the fitment as a whole so that upon removal of same from the mold it is ready for assembly with the applicator ball and attachment to a container. It has been discovered that such molding procedure introduces certain weaknesses into the structure, particularly in the web and contiguous portions such as to create serious stresses which too frequently break under pressure of the applicator ball incident to closing the package. As a conse quence, the applicator becomes almost useless in that the web is unable to assume a normal position in which it can function to unseat the ball.

A major cause of the introduction of these stresses is that incident to filling of the mold cavity with the thermoplastic material, the latter is of necessity divided into several streams which flow around the aperture forming pins and must then be joined or welded together at points radially beyond the pins in order to provide a suitable web. These welded areas are not always effective over a period of time and frequently break or crack, with the objectionable results indicated above. Another deficiency arises indirectly from the fact that so-called center-gating is resorted to. This involves introducing the thermoplastic material substantially at the axis of the web and at this point the finished fitment must be torn or severed from the sprue. -This zone is a so-called chill point and is highly stressed and it has been found in practice that under pressure of the applicator ball these stressed portions crack open and often the cracks extend in random directions into adjoining areas of the web.

atent An object of my invention is to avoid all of the above noted objections through the very simple procedure of molding the ball holder, ball seat and web with the latter completely unperforated and then as a separate operation punching out the stressed axial portion of the web and simultaneously punching a plurality of liquid flow openings in the vicinity of the periphery of the web. It has been found that through this procedure all of the objections noted above are effectively overcome and the useful life of the applicator is extended very materially.

Other objects will be in part apparent and in part pointed out hereinafter.

In the drawings:

Fig. 1 is a fragmentary sectional view showing a mold with a fitment being produced therein, wherein pins extend into the mold cavity to form the dispensing openings simultaneously with the molding operation.

Fig. 2 is a sectional plan view taken substantially at the line 22 of Fig. 1 illustrating the flow of the thermoplastic material in the mold cavity and the manner in which the pins divide the stream so that the previously mentioned unreliable weding or joining of the streams radially beyond the pins is necessary.

Fig. 2a is a fragmentary plan view showing the web portion of the fitment indicating the manner in which stress cracking may occur in proximity to the liquid dispensing openings and at the axis of the web.

Fig. 3 is a view similar to Fig. 1 illustrating the modified mold equipment used to practice my present method of producing the ball holder.

Fig. 4 is a sectional plan view taken substantially at the line 44 of Fig. 3 and showing the unperforated web and axially thereof a small neck section of the sprue which according to my invention will be removed later by a punching operation.

Fig. 5 is a fragmentary side elevational view illustrating one form of punch mechanism capable of producing the desired openings in the web portion of the holder.

Fig. 6 is a fragmentary sectional view of the finished holder attached to a container and provided with a closure cap, this view being taken substantially on the line 66 of Fig. 7.

Fig. 7 is a sectional view taken substantially on the line '77 of Fig. 6 with the ball removed from its holder.

In Figs. 6 and 7, I have illustrated a ball-type liquid applicator or dispenser incorporating those features to which the present invention particularly pertains. This applicator is shown separably attached to a bottle or the like container having a diametrically reduced screwthreaded neck 11 defining a filling opening 12 and formed with a diametrically reduced upward extension 13 which terminates in an annular flat rim. An annuar generally downwardly facing abutment 14 just below the rim and externally of the upward extension 13 is designed for holding engagement with an internally ribbed attaching skirt 15 which forms a part of the applicator ball holder with which my present invention is specifically concerned.

This ball holder is formed of a suitable thermoplastic material such as polyethylene and includes a generally cylindrical housing 16 disposed coaxially with the neck 11 of the container. The upper portion of this holder is shaped to removably and rotatably support an applicator ball 17. The lower end of the housing is formed with a diametrically reduced neck portion 18 which projects into the container neck. A transverse axially flexible and resilient web 19 extends across and is moded integral with the lower or innter end of the neck 18. A ball seat 20 is formed internally of the holder substantially at the upper end of the neck-like extension 18. A

closure cap 21 is intended to be telescoped over the applicator ball and its holder and threaded onto the neck 11 of the container 10.

The web 19 is provided with a plurality of liquid flow openings 22 near its periphery to permit How of a liquid from the container and onto the applicator ball 17 preparatory to transfer of such liquid in a thin film to the desired surface. Heretofore, these openings have been molded in the web, simultaneously with the initial molding of the ball holder fitment, such being obtained by properly positioned pins 23 in the mold cavity. In Figs. 1 and 2, a typical mold is illustrated, such including a plug 24 carrying the pins 23 and shaped to form the interior of the fitment, a body mold 25 and a combined bottom-forming mold and injection nozzle 26. This latter element, the nozzle 26, is formed with an axial sprue opening 27 having a gate 28 opening into the mold cavity at the axis of the web 19. As has been explained heretofore, as the thermoplastic molding material enters the mold cavity, it moves radially outward in all directions from the gate 28 and upon reaching the pins 23 is divided by them into several streams which, in order to produce a complete web must be joined or welded together immediately as the material passes these pins 23 and moves outwardly to completely fill the mold cavity. Following the molding operation, the mold is opened and the holder or itment is severed from the sprue leaving a small neck portion 29 at the axis of the web. It has been determined that this is a serious chill point often very highly stressed and when subjected to downward movement under pressure of the applicator ball tends to crack open with the result that the web lacks sufficient resilience to again move upwardly and unseat the ball for dispensing purposes. Moreover, such cracks as develop in this otherwise relatively isolated zone often spread radially outward into other areas. Also, as has been explained previously, it is not uncommon for the Web and perhaps contiguous portions of the neck to crack or break in the zones of welding of the several radially outwardly moving streams of thermoplastic material, with the result that the web completely loses its ability to move upwardly and effect unseating of the applicator ball. In Figs. 2 and 2:1, I have endeavored to illustrate the manner in which the molding material flows about the opening forming pins 23 and the weld lines where stress cracking occurs and at the axis of the web where the molding material enters the cavity.

The above described intolerable conditions are entirely avoided as a result of forming the web 19 initially as a solid unperforated element and later punching out the material at isolated points to form the several openings 22 and punching out the chilled stressed portion at and immediately adjacent to the axis of the web. In Fig. 3, I have shown the mold as being formed without the pins 23 illustrated in Fig. 1 so that the molding material flows freely from the gate of the sprue opening and without interruption to all portions of the mold cavity and in such fashion that it is not divided into several streams that must be welded together. Of necessity, there is a short axial neck 29a on the web 19 and as has been explained heretofore this neck and contiguous portions of the web are severely chilled and stressed and should be removed in order to insure against later possible severe cracking of the web in this area. Accordingly after the molded fitment has been removed from the cavity, it is placed in a punch press 30 including a holder 31 and punch 32, the latter constructed to punch out material to produce the three dispensing openings 22 in the web and-simultaneously punch out the center portion of the web thereby removing the neck 29a and other stressed material in this immediate vicinity and incident thereto forming a central opening 33.

It will be appreciated that in a fitment produced in the fashion described above the web 1.9 (Fig. 6) can be flexed axially downward to permit seating of the applica tor ball 17 under pressure of the closure cap 21 and thereby effect reliable sealing of the container. Upon removal of the closure cap preparatory to use of the device, the web, due to its inherent resilience and having been formed so that no stress-cracking has developed, will immediately move axially upward and unseat the applicator ball 17.

Modifications may be resorted to within the spirit and scope of the appended claim.

I claim:

In the method of producing a ball holder for a liquid applicator which is formed of a thermoplastic material and comprises a generally cylindrical housing, an apertured transverse web at one end of the housing, an annular internal ball seat axially inward from said web and a ball confined in part within the housing, the web being of such thickness as to be resilient and capable of axial flexing under pressure applied to seat the ball and returning to an unfiexed position with removal of such applied pressure to thereby unseat the ball; the steps which consist in introducing thermoplastic material in fiowable state into a mold cavity at a point substantially coaxial that portion of the mold in which the web will be formed, causing uninterrupted lateral flow of the inroduced material in all radial directions away from said point to form the web and thence in directions to fill the cavity thereby to complete formation of the holder, removing the holder from the mold with a sprue on one side of and at the axis of the web, supporting the web against flexing and axially punching out the sprue and sufficient additional material in an annular area contiguous to and coaxial with the sprue and at a plurality of points intermediate the sprue and the margin of the web to form a multiplicity of dispensing apertures.

References Cited in the file of this patent UNITED STATES PATENTS 294,490 Merritt ct al Mar. 4, 1884 1,318,700 Skolnick Oct. 14, 1919 2,097,144 Christensen Oct. 26, 1937 2,613,395 Massler Oct. 14, 1952 2,630,601 Shiffer et al Mar. 10, 1953 2,698,460 Amo Jan. 4, 1955 2,698,464 Wilson Jan. 4, 1955 FOREIGN PATENTS 564 Great Britain Feb. 11, 1904

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