FIELD

The present disclosure relates to a plastic tank, particularly a plastic fuel tank, with a pot-like installation body arranged on the inside of the tank, as well as a method for installing an installation body in a plastic tank, preferably a tank module in a plastic fuel tank.

BACKGROUND

In the case of fuel tanks, the so-called tank module may be securely fastened on the tank bottom, with the tank module being an installation body that accommodates a specific fuel volume and in which a fuel pump is arranged, and so said fuel pump does not run dry even at a low fuel filling level in the tank or no pumping gaps are caused.

SUMMARY

The present disclosure provides apparatus and methods for securely fastening the installation body on the tank bottom in a safe manner and without great installation effort or extensive additional components.

For example, in order to avoid plastic welding processes during the arrangement of the installation body, a ring body, which is arranged on an end portion of the installation body, is provided according to the present disclosure, wherein the ring body is engaged in an undercut section in the tank wall, and the installation body is engaged in the ring body. The installation body is preferably designed as a tank module for receiving a fuel pump and storing a fuel volume.

The undercut section in the tank wall can be produced in a blow mold by means of sliders which act on the tank wall from outside and are movably arranged in the blow mold. Alternatively, the undercut section can be produced in the tank wall by a molded part placed in a blow mold.

Expediently, the undercut section is essentially designed so as to be circular and can consist of at least two, preferably three, separate parts.

In a preferred embodiment of the present disclosure, the ring body has outward facing retaining ribs on the side of the tank wall, the free ends of which lie on a circle prior to the engaging of the installation body in the ring body; the diameter d of said circle being smaller than the diameter D of a circle which defines the free inner diameter of the undercut section. In addition, the ring body can have a cylindrical wall section with openings, in which engaging protrusions on an outer wall section of the installation body can be engaged.

Expediently, the outer wall section of the installation body having the engaging protrusions is essentially designed so as to be cylindrical, and having a diameter which is no greater than the diameter D of the free inner diameter of the undercut section minus the thickness of the wall section of the ring body having the openings. If the above-mentioned dimensions are precisely synchronized, a secure attachment of the installation body without play on the tank wall is ensured.

The method according to the present disclosure for installing an installation body in a plastic tank, preferably a tank module in a plastic fuel tank, comprises the following steps:Introduction of an undercut section in a tank wall on the inside of the tank;Pre-assembly of a ring body and the installation body;Positioning of retaining ribs of the ring body in the undercut section;Pressing the installation body into the ring body, wherein the installation body is engaged in the ring body, and the ring body is engaged in the undercut section.

When engaging the ring body in the undercut section, a section of the ring body, which carries the retaining ribs, can be spread open, and the retaining ribs can be pressed into the undercuts of the undercut section. Furthermore, when the installation body engages in the ring body, engaging protrusions on a cylindrical wall section of the installation body, which is introduced into the ring body, can be engaged in openings in a complementary wall section of the ring body.

Preferably, the undercut section in the tank wall is produced from outside in the course of a molding of the tank in a blow mold. This can be accomplished by means of sliders arranged in the blow mold or alternatively by a molded part placed in a blow mold, around which the tank wall is formed during blow molding while creating the undercut section. While sliders in the blow mold can be reused for each new molding process, a new molded part must be provided for each new tank with said molded part remaining in the tank wall; however, in such case, the sliders in the blow mold can be omitted, and so the blow mold is designed less elaborately.

According to another aspect of the present disclosure, a method for installing an installation body in a plastic tank includes the steps of forming an undercut section on a tank wall, arranging a ring body an end of the installation body to define a pre-installation configuration, setting up an intermediate position by locating a bottom-side end of the ring body with the installation body in the undercut section on the tank wall, and inserting the bottom-side end of the ring body into the undercut section by pushing the installation body into the ring body to define an installed configuration.

According to a further aspect of the present disclosure, the step of forming the undercut section on the tank wall includes the steps of locating a molded part between a blow mold and an outer side of the tank wall, and engulfing the molded part by a part of the tank wall during a blow molding process.

According to a further aspect of the present disclosure, the step of forming the undercut section on the tank wall includes the step of laterally arranging sliders in a blow mold relative to a recessed area formed in the tank wall, and moving the sliders toward one another.

According to a further aspect of the present disclosure, the undercut section is formed to protrude toward an inner side of the tank.

According to a further aspect of the present disclosure, the step of arranging a ring body on an end of the installation body includes the step of inserting a section of the end of the installation body in a space formed in an interior of the ring body for holding together in a frictionally engaged manner.

According to a further aspect of the present disclosure, the bottom-side end of the ring body is formed with at least one retaining rib so that the retaining rib is pressed into the undercut section. A first diameter d defined by a circumcircle of the retaining ribs is smaller than a second diameter D defined by an inside circle of undercut parts formed in the undercut section. In the step of inserting the bottom-side end of the ring body into the undercut section by pushing the installation body into the ring body, an area of the retaining ribs is spread open and the retaining ribs are securely fastened into the undercut section. In addition, engaging protrusions formed on a cylindrical wall of the installation body is securely engaged with openings formed in complementary wall of the ring body.

