A DISPENSER OF PASTE PRODUCTS, IN PARTICULAR TOOTHPASTE

Abstract: A dispenser of paste products, in particular toothpaste, is composed of a cylindrical container (2) provided with a headpiece (4) carrying paste product output means and with a bottom wall (5) fitting in an airtight manner therein for sliding movement one way toward the headpiece. The bottom wall (5) consists of a plunger body (6) having an axial cavity (7) which is open downwardly and communicates, through radial passages (13), with the interior (14) of the container (2), and of a dish-shaped body (15) provided with a lug (16) which fits snugly into the axial cavity (7). The outer surface of the lug (16) on the dish-shaped body is provided with ribs (21) which form, in co-operation with the inner wall of the axial cavity(7) in the plunger body (6), channels (23) extending along paths including at least one sharp change in direction. On completion of the container (2) filling operation, the bottom wall (5) is inserted and pushed against the toothpaste whilst trapped air is vented out through the channels (23,24). Once the air has been vented out, the flow of toothpaste which follows will stagnate inside the channels (23,24) and seal them off, without flowing out of the container (2). Thus, the advantage is secured of having a bottom wall (5) which automatically provides an airtight closure once the trapped air has been vented out.

Description: This invention relates to a dispenser of generic paste products, and in particular toothpaste, being of a type which comprises a cylindrical container having a vertical longitudinal axis, a headpiece provided with an output means for the paste product and located at the top end of the container, and a bottom end structure arranged to slide in a tight manner inside the container in one direction toward the headpiece. A dispenser of the same kind as specified above is described, in EP-A-214106 More particularly, the invention is concerned with the construction of the bottom end structure, which is designed to close the container and, consequently to the pumping action exerted through the paste output means, to move up toward the headpiece while restrained from moving back down, thereby being effective to reduce the container volume by a corresponding amount to the volume of the dispensed paste. It is known that such dispenser types are filled with their output mechanisms mounted to the headpiece by introducing the paste product through the open bottom of the container. This bottom is then closed by fitting in the sliding wall. That operation poses some problems for its carrying out, of a mechanical as well as hydraulic nature, because at the time of fitting in the bottom end structure attention should be paid to that any air trapped in between the paste introduced into the container and the bottom end structure be thoroughly removed. It is, in fact, only in the total absence of air that the bottom end structure can be made to intimately contact the paste all over and slide up the container by virtue of the pressure differential which is created at each dispensation between the outward side of the wall and the top of the column of paste inside the container. After all the air has been vented out, however, the bottom end structure is to both prevent the paste from seeping out and a fresh air cushion from forming , and therefore to provide an air-tight seal. In accordance with a prior art approach, of which DE-A-3435576 is an example, the bottom end structure is formed with an axial channel which opens both to the container inside and the outside, and a plug is pushed into the channel opening to shut it tightly after the container has been filled, and trapped air vented out completely. This prior approach apparently requires, however, that the bottom end structure be pushed against the mass of toothpaste until the latter begins to overflow, in order to make sure that all the air has been removed and, accordingly, achieve an air-tight fit of the bottom end structure. In view of the characteristics of the automatic filling equipment employed, the detection of the exact moment when the air-tight fit can be correctly completed for the bottom end structure involves a setup of checking arrangements and procedures which are bound to affect the product economy adversely. The problem which underlies this invention is, therefore, to provide a bottom end structure for dispensers of the kind specified above, which can be positioned within the container, after filling the latter, and urge against the toothpaste to permit venting of the trapped air, but requires no checking step to signify that the air has been thoroughly vented out, and implies no need to arrange for and subsequently apply closure means to ensure its air-tightness. This problem is solved by a dispenser according to the appended claim 1. The invention will be now described with reference to a non-limitative embodiment thereof as illustrated in the accompanying drawings, where: Figure 1 is a part-sectional view showing in perspective a dispenser of paste products incorporating a bottom wall according to the invention; Figure 2 is an enlarged scale detail view of the bottom wall according to the invention; and Figure 3 is a perspective view of a dish-like body of the bottom wall. With reference to the drawing views, a dispenser 1 comprises a tubular cylinder container 2 having a vertical axis X-X and, located at its bottom end, an annular flange 3 facing outwards and forming a pedestal, with the top end of the container mounting a headpiece 4 which is provided with an output means, not shown, such as that described in EP-A-214106. Fitted inside the cylindrical container 2, a bottom end structure generally indicated at 5 is arranged to slide in an airtight manner one way from the pedestal 3 toward the headpiece 4 in consequence of the dispensation of paste product from the container 2. That bottom end structure 5 consists of a plunger body 6 which is formed with an axial cavity 7 having a circular cross-section and being closed at its end 8 facing the interior of the container 2 and open at the outward-facing end 9. The axial cavity 7 structure is defined by a first cylindrical section 10 facing the closed end 8, a second section 11, also cylindrical, facing the open end 9, and a frusto-conical intermediate connection section 12 formed with radial apertures 13 which communicate the interior 14 of the container 2 with the axial cavity 7. The bottom end structure 5 further comprises a dish-shaped body 15 having a lug 16 which extends coaxially with the cavity 7 of the plunger body 6 into which it makes a push fit in a non-airtight manner for reasons and to provide features to become clear herein below. More particularly, the lug 16 comprises a first cylindrical section 17 having such a diameter dimension as to make a push fit into said first section 10 of the axial cavity 7, a second cylindrical section generally indicated at 18 and formed with one or more diameters which are all smaller than the inside diameter of the section 11 of the cavity 7, and a radially-extending step 19 located in front of an annular rim 20 which surrounds the opening 9 of the axial cavity 7. In accordance with the invention, and with reference in particular to Figure 3, the section 18 of the lug 16 is provided with a plurality of spaced-apart ribs 21 which extend radially for a distance selected to cause their ends to engage forcibly with the inner wall of the section 11 of the cavity 7. The step 19 of the lug 16 is also provided with radial ribs 22 at such mutual spacings as to form extensions of the ribs 21. Such radial ribs 22 extend axially to snugly abut with their free ends against the flat surface of the annular rim 20 which surrounds the opening 9 of the axial cavity 7. Accordingly, between the ribs 21 and the opposedly located surface of the cavity 7 there are formed axial channels 23 which are extended radially with a sharp change of direction into an equal number of channels 24 formed between the ribs 22 and the opposed surface of the annular rim 20. The cross-section of each channel is selected to suit the viscosity of the paste product filling the container 2. For example, with viscosities within the range of 25,000 to 75,000 mPa sec, the minimum cross-sectional area of each channel 23 and 24 would be about 0.05 mm². The set of channels 23 and 24 are communicated, at one end, with the interior of the container 2 through radial apertures 13, and at the other end as indicated by arrows, with the outside environment through the interspace 25 left between the plunger body 6 and the dish-shaped body 15 stiffened by radial rib formations 26. It may be appreciated from the foregoing description that, with' the bottom end structure, as consisting of the pre-assembled plunger body 6 and dish-shaped body 15 combination, fitted into the container 2 and being conventionally pushed by the packaging machine, against a paste product previously loaded into the container, air trapped during the filling operation would be vented out through the apertures 13 and the channels 23 and 24. As the push force continues to be applied, upon cessation of the outflow of air, the apertures 13 and at least the initial sections of the channels 23 are flooded with the paste product. As a result of the cross-sectional areas of the channels 23 and 24, of their overall length, and of the sharp change in `direction undergone by the flow between the channels 23 and 24, which factors would depend on the viscosity of the paste product to be dispensed, the paste product will flow outwards, but in stagnating and setting inside the channels 23 and 24, automatically seals off the bottom wall, thereby securing the results and advantages set forth for the invention, and this in particular without the need for checking provisions on the filling/packaging machine to sense completion of the trapped air venting and hence control the bottom end structure to close in an airtight manner.

Claims: A dispenser of paste products, in particular toothpaste, comprising a cylindrical container (2) having a vertical longitudinal axis, a headpiece (4) provided with an output means for the paste product and located at the top end of the container, and a bottom end structure (5) arranged to slide in a tight manner inside the container in one direction toward the headpiece, characterized in that in its final assembled condition said bottom end structure comprises a plurality of channels (23,24) each having one of its ends (13) open to the interior (14) of the container (2) while the other end opens to the container exterior, such channels (23,24) extending along paths which include at least one sharp change of direction and being provided each with a cross-section configuration such that when the dispenser is being filled in with paste from the top end the flow of paste therethrough, following the venting out of any air, will not reach the outside but instead stagnate within and seal off the channels. A dispenser according to Claim 1, characterized in that said bottom end structure comprises a plunger body (6) having an axial cavity (7) which is closed at its end (8) facing the interior (14) of the container (2) and open at the opposite end (9), said cavity (7) being formed with radial apertures (13) open to the container interior (14), and a dish-shaped body (16) provided with a lug (16) extending coaxially with the cavity (7) in the plunger body (6) and being a non-airtight push fit in the cavity (7) from the open end (9) thereof. A dispenser according to Claim 2, characterized in that, said axial cavity (7) is defined by a first cylindrical section (10) adjoining the closed end (8), a second cylindrical section (11) having a larger diameter than the first section (10) and adjoining the open end (9), and a frusto-conical intermediate connection section (12) formed with said radial apertures (13). A dispenser according to Claims 2 or 3, characterized in that said open end (9) of the axial cavity (7) is provided with an annular rim (20). A dispenser according to Claims 3 or 4, characterized in that the lug (16) on said dish-shaped body (15) comprises a first cylindrical section (17) having a diameter dimension whereby it fits snugly within said first section (10) of said axial cavity (7), a second cylindrical section (18) having a smaller diameter than said second section (11) of the axial cavity (7) and a radially extending step (19) located in front of said annular rim (20) of the open end (9) of the axial cavity (7). A dispenser according to Claim 5, characterized in that the outer surface of said second cylindrical section (18) of the lug (16) on the dish-shaped body (15) is formed with a plurality of axial ribs (21) projecting radially out at mutually spaced-apart locations, the free ends of said ribs (21) engaging forcibly with the cylindrical inner wall of a corresponding section (11) of the axial cavity (7) to form a plurality of intermediate axial channels (23) one end whereof is in communication with said radial apertures (13) provided in the frusto-conical intermediate section (12) of the axial cavity (7). A dispenser according to Claim 6, characterized in that said radially extending step (19) of the lug (16) on the dish-shaped body (15) is formed with a plurality of radial ribs (22) mutually spaced apart from one another and projecting in the axial direction, the free ends of said ribs (22) face abutting against the surface of said annular rim (20) on the open end (9) of the axial cavity (7) to form intermediate radial channels (24) communicating at one end with said intermediate axial channels (23) and at the other end with the outside environment.

Inventors: BATTEGAZZORE, PIERO
Applicants: GUALA S.P.A.
Application year: 1989
Main classification: B65D47
IPC codes: B65D83, B65D47