Pressure operated container for dispensing viscous products

Claim 2

A piston for a pressurized container having a viscous product and provided with a dispensing valve, said piston comprising a piston body portion of a generally tubular configuration and a resilient annular flange provided with a depending skirt portion on the outer wall of said piston body portion, said piston body portion being radially spaced from the inner wall of said skirt portion, said depending skirt portion being for contact with a container wall and being the only means of piston support, said skirt portion being relatively thin with respect to the space between said skirt portion and the piston body portion, said skirt portion having a large surface area of predetermined axial length; whereby, when said piston is inserted in a suitable container and when the space within said skirt portion is subjected to a predetermined charge of gas under pressure, said skirt portion will be pressure-loaded into peripheral and axially continuous light sealing and stabilizing contact with the container wall.

Claim 3

A piston as claimed in claim 1, wherein said piston body portion includes reinforcement means whereby said piston body portion is relatively stiff in relation to the resilience of said skirt portion.

Claim 4

A piston as claimed in claim 1, wherein the thickness of said skirt portion is in the range of 0.005 to 0.015 inch.

Claim 5

A piston as claimed in claim 1, wherein both said body portion and said resilient annular flange thereon are integral.

Claim 6

A piston as claimed in claim 1, wherein said piston body portion is constituted of a plastic.

Claim 7

A piston as claimed in claim 1, wherein said resilient flange projects radially outwardly from and axially away from the head end of said piston body portion.

Claim 8

In combination, a pressure container comprising an elongate cylindrical body with a closed upper end, dispensing-valve means in said upper end, a piston having a closed upper end and integral body structure extending downwardly within a cylinder spaced from the container wall and united to the closed end of said piston, a peripherally continuous flexible tubular flange carried by said piston within the annular space between the piston body structure and the container wall and of axial extent substantially less than that of said piston, said flange being relatively thin with respect to the space between said tubular flange and the piston body and having a periphery of substantially the inner wall-surface peripheral extent of the container body, with a relatively extensive area of flange-seal contact with the container wall by reason of the tubular structure of said flange, said tubular flange being the only means of piston suspension with respect to the container wall, whereby a product chamber is defined in the container space between the flanged piston and the valved end of the container, pressure-sealing means closing the lower end of said container to define a pressure chamber beneath said piston, and a predetermined charge of gas under pressure in the pressure chamber and pressure-loading said tubular flange into peripheral and axially continuous light sealing and stabilizing contact with the container wall.

Claim 9

In combination, a pressure container comprising an elongate cylindrical body with a closed upper end, dispensing-valve means in said upper end, a piston having a closed upper end and integral body structure extending downwardly within a cylinder spaced from the container wall and united to the closed end of said piston, a peripherally continuous flexible tubular flange carried by said piston within the annular space between the piston body structure and the container wall and of axial extent substantially less than that of said piston, said flange being relatively thin with respect to the space between said tubular flange and the piston body and having a periphery of substantially the inner wall-surface peripheral extent of the container body, with a relatively extensive area of flange-seal contact with the container wall by reason of the tubular structure of said flange, said tubular flange being the only means of piston suspension with respect to the container wall, whereby a product chamber is defined in the container space between the flanged piston and the valved end of the container, pressure-sealing means closing the lower end of said container to define a pressure chamber beneath said piston, and a predetermined charge of gas under pressure in the pressure chamber and pressure-loading said tubular flange into peripheral and axially continuous light sealing and stabilizing contact with the container wall.

Claim 10

The combination of claim 7, in which said container body has a top opening, said dispensing-valve means being assembled to said body at the top opening after dispensable product is loaded through the opening.

Claim 11

The combination of claim 7, in which said closed upper end of said container is a conical reduction from said cylindrical body to a central valve-locating opening.

Claim 12

The combination of claim 9, in which the slope of the conical reduction is in the range of substantially 35* to substantially 55* off the container-body axis.

Claim 13

The combination of claim 9, in which the slope of the conical reduction is apprOximately pi /4 radian off the container-body axis.

Claim 14

The combination of claim 9, in which said valve means comprises a resilient bushing having a central body and an integral conical flange generally conforming to the inner surface of the conical reduction of the container and peripherally continuously sealing said bushing to the container, and a headed dispensing-valve member having a stem portion extending through said bushing and located thereby.

Claim 15

The combination of claim 12, in which said central body projects downwardly and radially clear of the lower end of said conical flange, said head seating against said central body and radially clear of said conical flange, whereby said conical flange is relatively free to maintain the sealed relationship to said container while accommodating eccentric-displacement forces upon tilted actuation of said stem portion.

Claim 16

The combination of claim 12, in which said central body includes a radially outward shoulder overlapping the axially outer end of the container end-wall opening.

Claim 17

The combination of claim 14, in which said central body has a convergent taper upward of said shoulder, the diameter of said taper at the upper end thereof being less than that of the container end-wall opening, and the slope of said taper being at a lesser angle to the container axis than that of the conically reduced container end wall.

Claim 18

The combination of claim 9, in which said conically reduced end wall is integrally formed with said cylindrical body.

Claim 19

The combination of claim 7, wherein said piston body and tubular flange are parts of the same single injection-molded plastic article.

Claim 20

The combination of claim 17, wherein the wall thickness of the closed end of said piston is substantially greater than that of said tubular flange.

Claim 21

The combination of claim 9, wherein the upper wall-surface contour of the closed end of said piston includes an outer frusto-conical annulus of slope conforming to that of said conical reduction.

Claim 22

The combination of claim 9, wherein the portion of said valve means exposed internally of said container is characterized by a central convex spherical contour, and wherein the upper surface of the closed end of said piston is characterized by a central spherical concavity substantially matching the said convex contour.

Claim 23

The combination of claim 20, wherein said valve means includes a resilient bushing carried at the container end-wall opening and a headed dispensing stem extending through said bushing with the head seated against the axially inner end of said bushing, said head having said convex spherical surface of radius in the order of magnitude of axial offset of said head from the instantaneous center of tilt afforded to said stem by reason of the resilient-bushing support thereof, whereby said spherical surfaces will not substantially oppose tilt of said stem even when the fully advanced piston position is reached.

Claim 24

The combination of claim 17, wherein said piston body comprises a cylindrical sheath with internal elongate stiffening ribs at angularly spaced locations.

Claim 25

The combination of claim 7, in which the peripheral extent of said tubular flange is slightly less than that of the adjacent cylindrical container-body wall surface, the material of said flange being sufficiently flexible to inflate into peripherally continuous container-wall contact in response to super-atmospheric pressure in said pressure chamber.

Claim 26

The combination of claim 7, in which the radial offset of said tubular flange from said body structure is in the order of 5 to 15 percent of the outer radius of said tubular flange.

Claim 27

The combination of claim 7, in which the radial offset of said tubular flange from said body structure is substantially ten percent of the outer radius of said tubular flange.

Claim 28

The combination of claim 7, in which the overall diameter of said tubular flange exceeds the axial length of said piston.

Claim 29

The combination of claiM 26, in which the ratio of said overall diameter to said axial length is in the order of 4:3.

Claim 30

The combination of claim 26, in which said tubular flange is connected to said piston body near the upper end thereof, said tubular flange being of effective axial length less than one half the overall axial length of said piston.

Claim 31

The combination of claim 28, in which the extent to which overall axial length of said piston exceeds the effective axial length of said tubular flange is substantially threefold.

Claim 32

In combination, a pressure container comprising an elongate cylindrical body with a closed upper end, dispensing-valve means in said upper end, a piston having a closed upper end and integral body structure extending downwardly within a cylinder spaced from the container wall and united to the closed end of said piston, a peripherally continuous flexible tubular flange carried by said piston within the annular space between the piston body structure and the container wall, said flange being relatively thin with respect to the space between said piston body and the container wall and being the only means of piston suspension with respect to the container wall, said flange having a periphery of substantially the inner wall-surface peripheral extent of the container body and being of axial extent substantially less than that of said piston body structure, whereby a product chamber is defined in the container space between the flanged piston and the valved end of the container, pressure-sealing means closing the lower end of said container to define a pressure chamber beneath said piston, and a predetermined charge of gas under pressure in the pressure chamber and pressure-loading said tubular flange into peripheral and axially continuous light sealing and stabilizing contact with the container wall.

Claim 33

In combination, a pressure container comprising an elongate cylindrical body with a closed upper end, dispensing-valve means in said upper end, a piston having a closed upper end and integral body structure extending downwardly within a cylinder spaced from the container wall and united to the closed end of said piston, a peripherally continuous flexible tubular flange carried by said piston within the annular space between the piston body structure and the container wall, said flange being relatively thin with respect to the space between said piston body and the container wall and being the only means of piston suspension with respect to the container wall, said flange having a periphery of substantially the inner wall-surface peripheral extent of the container body and being of axial extent substantially less than that of said piston body structure, whereby a product chamber is defined in the container space between the flanged piston and the valved end of the container, pressure-sealing means closing the lower end of said container to define a pressure chamber beneath said piston, and a predetermined charge of gas under pressure in the pressure chamber and pressure-loading said tubular flange into peripheral and axially continuous light sealing and stabilizing contact with the container wall.