GB2161863A

GB2161863A - Dispenser for pasty products

Info

Publication number: GB2161863A
Application number: GB08503818A
Authority: GB
Inventors: David G Moore
Original assignee: Realex Corp
Current assignee: Realex Corp
Priority date: 1984-07-16
Filing date: 1985-02-14
Publication date: 1986-01-22
Also published as: AU3890185A; DE3507134C2; FR2567490B1; CA1305949C; GB2161863B; DE3507134A1; AU579850B2; JPS6133963A; FR2567490A1; GB8503818D0

Abstract

In a manually operated dispenser especially suited for striped toothpaste products and the like a reciprocable pumping piston (28) is provided with a concave, product-engaging face (44) that gently, yet forcibly, directs the product (62,64,66,68,70) in a smooth, laminar flow out of the pump chamber (32) and into the discharge spout (34) when the piston (28) is depressed through a pumping stroke so that stripes in the ribbon of toothpaste issuing from the spout (34) are well defined and maintained in an aesthetically pleasing manner. The cooperating floating takeup piston (16) at the opposite end of the chamber (32) from the pumping piston (28) is provided with a convex dome (17) that becomes complementally received within the concavity of the pumping piston (28) when the contents of the dispenser are nearly depleted, thereby maximizing the degree to which the dispenser is emptied. <IMAGE>

Description

SPECIFICATION Dispenser for pasty products Description This invention relates to the field of manually operated pumping dispensers and, more particularly to improvements in dispensers of the type which are especially adapted for handling viscous products such as striped toothpaste and the like.

One important object of the present invention is to provide a dispenser that is especially, although not exclusively, suited for dispensing a viscous, axially striped product by virtue of the dispenser's ability to pump the product under pressure without destroying or otherwise adversely affecting the integrity and clear definition of the stripes throughout the product.

To this end, the present invention provides a dispenser for pasty products, wherein a pumping piston has a product discharge passage leading from an opening in the piston and a concave product-engaging face having regions which converge inwardly to the opening and passage for directing product gradually toward and into the latter during the pumping stroke of the piston. The avoidance of turbulence, agitation and sharp directional changes in the product as it is subjected to pumping pressures has been found to be especially beneficial in preserving the integrity of the stripes.Moreover, constructing the pumping piston in a manner to achieve such results has also led to a decrease in the finger pressure required to manually effect a pumping stroke and to a decrease in any deformation of the piston face which could otherwise iead to undesirable product blow-by around the sealing edge of the piston.

Preferably, a takeup piston is disposed in opposition to the pumping piston to cooperate with the latter in defining a pumping chamber therebetween, the takeup piston is progressively movable toward the pumping piston to reduce the volume of the chamber as the supply of product is depleted therefrom and has a product-engaging convex face configured complementally with the face of the pumping piston for reception within the latter upon engagement of the takeup piston with the pumping piston. This results also in improved sealing around the interface between the takeup piston and the chamber.

A preferred embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings.

Brief Description of the Drawings Figure 1 is a vertical cross-sectional view of a dispenser constructed in accordance with the principles of the present invention with the actuating lever thereof in its undepressed, standby position and the spout outlet closed by the valve portion of the lever; and Figure 2 is a vertical cross-sectional view of the dispenser similar to Fig. 1 but showing the dispenser filled with a striped product and the actuating lever depressed.

Description of the Preferred Embodiment Figs. 1 and 2 show a dispenser 10 having a tubular cylindrical body 1 2 which is open at its lower end 14 to the atmosphere, except for the presence of a floating piston 1 6 which makes sealing engagement with the interior wall surface of the body 1 2 and has a downwardly and outwardly flaring metal skirt 1 8 or the like on the bottom side thereof which also engages the interior wall surface of the body 1 2. The skirt 18 is sufficiently resilient that it will deflect downwardly to any extent necessary to permit the piston 1 6 to move upwardly in the body 1 2 yet is sufficiently stiff as to bite into the wall surface and prevent downward, retrograde movement of the piston 1 6 within the body 1 2. The opposite upper end 20 of the body 1 2 includes an upright, centrally disposed, reduced-diameter sleeve 22 which is supported by transversely extending web means 24.

The sleeve 22 reciprocably receives the tubular stem 26 of a pumping piston 28 which at its circumferential periphery sealingly engages the inner wall surface of the body 1 2. A passage 30 is defined within the tubular stem 26, and the two pistons 1 6 and 28 cooperate with the body 1 2 to form a pumping chamber 32 therebetween.

The sleeve 22 also partially receives the lower end of a tubular discharge spout 34 which itself receives the upper end of the plunger stem 26 and is securely attached thereto. A passage 36 is defined within the tubular spout 34, and a discharge outlet 38 is presented at the uppermost end thereof. A coil spring 40 encircles the piston stem 26 and is trapped between the lower extremity of the spout 34 and a lower, inturned terminus 42 of the sleeve 22 for the purpose of yieldably biasing the piston 28 and the spout 34 toward an upper, undepressed position as illustrated in Fig. 1.

The dispenser 10 is also provided with an actuator 46 in the form of a lever having a fulcrum 48 associated with the spout 34. The fulcum 48 takes the form of a pair of pins projecting laterally from opposite sides of the spout 34, and a pair of legs 50 of the actuator 46 (only one leg 50 being illustrated) straddle the spout 34 and rest at their midpoints on the respective fulcrum pins 48. Forwardmost ends of the legs 50 are retainingly hooked beneath overhanging proximal ledges 52 (only one being shown) on upstanding housing structure 54 at the upper end 20 of the body 12.

The actuator lever 46 includes a fingerengaging portion 56 on one side of the ful crum pins 48, as well as a valve flap portion 58 on the opposite side of the fulcum pins 48. The valve portion 58 is integrally connected with the finger-engaging portion 56 by an intermediate web portion 60, and it will be noted that the valve portion 58 is of such a dimension as to completely cover and thereby close the outlet 38 when the actuator 46 is in its Fig. 1 position. If desired, the spout 3 may have an angled upper end as shown in order to best accommodate the valve portion 58 and a web portion 60 of actuating lever 46.

The pumping piston 28 has a lower, product-engaging face 44 which is of smoothly arcuate, concave configuration. It is to be noted that although the face 44 is arcuate in the illustrated embodiment, it is also within the concepts of the present invention to provide such face 44 with sloping flat surfaces that converge toward the passage 30. The number of such sloping surfaces is largely discretionary.

The lower takeup piston 1 6 is provided with an upper, product engaging face 1 7 that is of smoothly arcuate, convex configuration complemental to that of the face 44 of pumping piston 28. Once again, although face 1 7 has been disclosed herein as being smoothly arcuate, it is within the scope of the present invention to achieve its convex configuration through sloping flat surfaces or the like, although it is preferred that, in any event, the face 1 7 be configured in a corresponding and complemental way with respect to the face 44.

Operation of the Preferred Embodiment The return spring 40 normally maintains the pumping piston 28, the spout 34, and the actuator 46 in the position of Fig. 1 in which the valve flap 58 tightly covers and seals the outlet 38. Upon the application of downwardly directed finger pressure to the operating portion 56 of the actuator 46, the latter rocks downwardly about the fulcrum pins 48 in a clockwise direction so that the valve flap 58 is lifted off the outlet 38 in substantially the same manner as illustrated in Fig. 2. At the same time, because the legs 50 are retained beneath the ledges 52, depression of the operating portion 56 also causes the spout 34 and hence the pumping piston 28 to be shifted downwardly a short distance.

This exerts a positive pumping pressure on the product contained within the chamber 32, forcing the same upwardly through the passages 30 and 36 and out the outlet 38.

When pressure on the operating portion 56 is released, the spring 40 returns the spout 34 to its original raised position of Fig. 1 and likewise forces the pumping piston 28 back to its original position. By virtue of the fulcrum pins 48 moving upwardly at this time and the legs 50 being trapped beneath the ledges 52, the actuator 46 is rocked in a counterclockwise direction about fulcrum pins 48 to thereby return the operating portion 56 to its original undepressed position and to lower the flap 58 once again into covering relationship with the outlet 38.In view of the evacuation of product within the chamber 32 and the closing of the outlet 38 by valve flap 58, the floating piston 1 6 is caused to be moved upwardly within the chamber 32 by a corresponding amount as atmospheric pressure is applied against the bottom of the piston 1 6 by the open lower end 14 of the body 1 2.

The gently arcuate, concave face 44 of the pumping piston 28 has the effect of easing the transfer of product from within the pumping chamber 32 to the spout 34. In this respect, whereas in prior dispensers the pumping face of the piston is normal to the path of travel of product therethrough and the product must therefore be converged centrally and turned sharply and abruptly at right angles, in the present invention downward movement of the pumping piston 28 tends to deflect or guide the product gently inwardly while at the same time pressing downwardly to force the product up through the passage 30.

This is quite significant when the product being dispensed has a number of axial stripes of sharply contrasting colors as illustrated in Fig. 2 where, for example, the stripes 62, 64, and 66 may be white, the stripe 68 red, and stripe 70 aqua. By converging the outer portions of the product inwardly toward the passage 30 at an oblique angle to the latter during the pumping stroke, it has been found that the stripes are much more prone to maintain their sharp, contrasting definition so that the bead of product ultimately dispensed will be aesthetically pleasing.

It has also been found that the concave configuration of the piston face 44 yields improved structural integrity as compared to prior pumping pistons having thin faces disposed normal to the path of product flow. In this respect it has been observed that the pressures developed during a pumping stroke had a tendency to deflect and deform such prior piston faces, thus also tending to pull the sealing peripheries thereof away from their interface with the pumping chamber. This could result in product blow by and leakage around the pumping piston under some conditions.

Furthermore, it has been noted that the concave configuration of the piston face 44 reduces the finger pressure required to depress the piston 28. Helpful in this regard is the lack of tubulence and agitation involved during the pumping action, all of which enhances the ease with which the piston 28 may be depressed.

On the other hand, the convex configuration of the takeup piston 1 6 assures that as the latter approaches the upper limits of its travel, the face 1 7 thereof will be complementally received by the concavity of the pumping piston 28. Consequently, evacuation of the product within chamber 32 is maximized, there being no remaining space for entrapment of product residue between the complemental faces 44 and 1 7 once the takeup piston 1 6 has fully risen into engagement with the piston 28.

Furthermore, it is believed that as a result of the convex configuration applied to the takeup piston face 17, an enhanced peripheral sealing action is obtained between takeup piston 1 6 and the walls of the chamber 32, perhaps as a result of product forces being directed downwardly along the domed face 1 7 and generally outwardly toward the sealing periphery of the piston 1 6.

Claims

1. A dispenser for pasty products, wherein a pumping piston has a product discharge passage leading from an opening in the piston and a concave product-engaging face having regions which converge inwardly to the opening and passage for directing product gradually toward and into the latter during the pumping stroke of the piston.

2. A dispenser according to claim 1, wherein the opening is located centrally with respect to the surface area of the face of the pumping piston.

3. A dispenser according to claim 1 or 2, wherein the face of the pumping piston is smoothly arcuate.

4. A dispenser according to claim 1, 2 or 3, wherein a takeup piston is disposed in opposition to the pumping piston to cooperate with the latter in defining a pumping chamber therebetween, the takeup piston is progressively movable toward the pumping piston to reduce the volume of the chamber as the supply of product is depleted therefrom and has a product-engaging convex face configured complementally with the face of the pumping piston for reception within the latter upon engagement of the takeup piston with the pumping piston.

5. A dispenser according to claim 4, wherein the face of the takeup piston is smoothly arcuate.

6. A dispenser for pasty products, substantially as hereinbefore described with reference to the accompanying drawings.