The invention relates to a synthetic resin lid for blow-molded synthetic resin barrels, with an outer rim surrounding the barrel neck and with an inner rim entering into the barrel neck and projecting past the lid bottom below the barrel opening, as well as with a sealing ring inserted between the outer lid rim and the inner lid rim, this sealing ring being urged against the opening rim of the barrel neck by means of a clamping ring or tightening wire, wherein the clamping ring or tightening wire extends over a flange or flange sections molded to the bottom of the outer rim of the lid and extends underneath a solid border which latter protrudes radially toward the outside at a spacing below the barrel opening from the barrel wall, this border being designed as a continuously extending flange or being subdivided into flange sections.
In such a lidded barrel, known from DE 2,544,491 C 2, stacking forces and axial impact forces occurring during dropping are transmitted to the barrel border via the outer flange formed at the lower rim of the lid. Considerable bending moments are produced thereby so that there is the danger of damage to the lid flange and/or the barrel border, as well as to the clamping ring, and the barrel becomes leaky and useless.
The invention is based on the object of providing a synthetic resin lid which is improved with regard to its functional safety.
This object has been attained according to the invention by the features of claim 1.
Suitable further developments of the invention are characterized in the dependent claims.
The synthetic resin lid of this invention is distinguished by the following advantages:
Stacking stresses and axial stresses occurring suddenly, for example when dropping from a height, are directly transmitted into the barrel jacket via the lid while the gasket is not overstressed at any location and thus exerts a uniform sealing effect. As a result, neither the outer flange at the lower lid rim nor the barrel border are exposed to bending stresses. The sealing arrangement of the lid can be utilized for barrels with a clamping ring lid closure or with a tightening wire lid closure. On account of the always constant pretensioning in the sealing rings, fatigue of the sealing ring material is prevented and therefore a permanent sealing action is achieved. In case of an unexpected damage to a sealing ring of the tandem gasket, leakproofness is still ensured at all times by the second sealing ring.
The invention will be described below with reference to a wide-necked barrel with clamping ring closure and a barrel with tightening wire closure. In the drawings:
FIGS. 1 and 2 show the barrel neck region of a wide-necked barrel with clamping ring closure and continuously extending barrel border, namely, in FIG. 1, in the opened condition and, in FIG. 2, in the closed condition,
FIG. 3 shows the same barrel neck region of a barrel with interrupted border,
FIG. 4 shows the barrel neck region of a wide-necked barrel with tightening wire closure, and
FIGS. 5 through 12 show various embodiments of the lid gasket.
A lid 1 injection-molded of a synthetic resin, in accordance with FIGS. 1 and 2, for a wide-necked barrel 2 exhibits an outer rim 4 encompassing the barrel neck 3 and an inner rim 5 entering into the barrel neck 3, this inner rim projecting beyond the lid bottom 6 below the barrel opening. The outer and inner lid rims 4, 5 form an annular chamber 7, an annular web 8 projecting axially from the bottom of this chamber. According to FIG. 1, the annular web 8 is surrounded by a molded-on bicomponent sealing compound 9, for example polyurethane with curing agent.
During closing of the lid 1 by means of a clamping ring 10, which latter extends over a continuous flange 11 molded at the bottom to the outer lid rim 4 and subtends a solid border 12 projecting from the barrel wall radially toward the outside at a spacing below the barrel opening, the annular web 8 is pressed onto the opening rim 14 of the barrel neck 3, with subdivision of the sealing compound 9 into two sealing rings 13, the sealing rings 13 being pretensioned past the opening rim 14 (FIG. 2). With the clamping ring 10 being closed, the flange 11 and the border 12 are not in contact with each other so that axial forces acting on the lid 1 are transmitted safely and directly into the barrel neck 3 and thus into the barrel body.
FIG. 3 shows the same lid 1 for a wide-necked barrel 2' wherein the border 12' is designed in the form of flange sections.
FIG. 4 shows a lid 1' with the same gasket arrangement for a wide-necked barrel 2' having the same border 12' subdivided into flange sections. A tightening wire 15 utilized for closing the lid 1' subtends the flange sections of the border 12' and extends over flange sections 16 molded at the bottom to the outer lid rim 4', the outer lid rim 4' penetrating the interspaces between the flange sections of the border 12', and the flange sections of the border 12' as well as the flange sections 16 of the outer lid rim 4' forming wedge-shaped contact surfaces for the tightening wire 15.
In the embodiments of the sealing arrangement according to FIGS. 5-12, the two sealing rings 13 are joined by way of a thin connecting web 17. The embodiments of the sealing arrangement according to FIGS. 5 through 8 and 10 through 12 each show a lid with an annular web 8 exhibiting a broadened supporting surface 18. In the gasket arrangement according to FIG. 9, the supporting surface 18 is defined by the width of the annular web 8.
FIGS. 5-12 show furthermore various design possibilities for the opening rim of the barrel neck for the mounting of the sealing rings 13 and/or their connecting web 17.
A labyrinth-like seal is obtained for the lid 1 or 1' by means of a profiled, e.g. serrated (FIG. 8) or undulated (FIG. 10) design of the opening rim.