Pipe fitting

Details Pipe fitting Pipe fitting

1999-09-10

2001-11-27

Nicholson, Eric K. (Department: 3627)

Pipe joints or couplings

Frangible element

C285S039000, C285S004000, C411S002000, C411S003000

Reexamination Certificate

active

06322108

ABSTRACT:

FIELD OF THE INVENTION
The present invention refers to a fitting to which a pipe, in particular a plastic material pipe or a composite plastics-metal pipe, may be connected to establish a pipe connection. In particular, the invention relates to such a fitting made of plastic material.
Recently, increased efforts were made to replace the conventional metal fittings with fittings of plastic material. Plastic material fittings are advantageous with a view to corrosion. However, plastic material is less stable than metal so that there is a risk of destroying the fitting—during mounting—to an extent where it becomes useless. This risk is particularly prevailing with threaded fittings screwed to another unit of the pipeline system.
From WO-A-96/03587, DE-U-93 10 556, DE-A-27 39 714 and U.S. Pat. No. 4,046,052, its is generally known to have threaded joint members provided between the portion to be engaged by a tool and the threaded joint body with means limiting the torque acting on the threaded joint body when turning the portion engaged by the tool.
It is an object of the present invention to provide a fitting, wherein the risk of the fitting being destroyed beyond usefulness when being screwed onto another unit of the pipeline system is reduced.
SUMMARY OF THE INVENTION
According to the invention, the object is solved with a fitting comprising
a fitting body with a longitudinal axis, having a pipe connection member for the sealed connection of a pipe and a thread for threadedly joining the fitting body to a connection unit, and
a portion on the fitting body to be engaged by a tool, to which a tool for turning the fitting body about its longitudinal axis may be applied for threadedly joining the same to the connection unit.
With this fitting, it is provided by the present invention that means are provided between the tool engaging portion and the fitting body that limit the torque acting on the fitting body when the tool engaging portion is turned.
With the present fitting, the portion of the fitting to which a tool (a wrench, a pair of tongs, or the like) is applied for turning and thereby screwing on the fitting, and the fitting body are connected by torque limiting means. Generally speaking, these are means that have a lesser shear resistance than the fitting body. Thus, when the fitting body is screwed on, the connection between the tool engaging portion and the fitting body is broken upon exceeding a torque defined by the shear resistance of the torque limiting means and exerted by the tool engaging portion.
Thus, in the present fitting body, the force engagement of the joint between the tool engaging portion and the fitting body is selected and set correspondingly. The force engagement is either obtained by frictional engagement, form fitting, material or component engagement or a combination of these.(In the context of this invention, “material or component engagement” is meant to include an engagement by bonding two materials or components, as by welding or by an intermediate layer, such as an adhesive.) Thus, e.g., by correspondingly selecting the fit between the fitting body and the tool engaging portion, a desired frictional engagement can be obtained. By selecting the bonding technique (welding, adhering), a desired material or component engagement can be obtained. Cooperating projections and recesses (the physical surface structure of the opposite faces of the tool engaging portion and the fitting body) can provide a desired form fitting.
If the fitting body and the tool engaging portion are integrally connected, it is feasible to provide for a weakening of the material in the region of the joint of the two elements of the fitting by forming passages, recesses or indentations, the weakening acting in the manner of a rated breaking point and extending concentrically around the longitudinal axis of the fitting.
Alternatively, a connecting element may be arranged between the fitting body and the tool engaging portion, having a lower shear resistance than the fitting body. Sin the context of the present invention, such connecting elements cover separate elements, but also a layer of adhesive. Advantageously, the connecting element is made from plastic material.
When metal is used as the material of the connecting element, the interface connection of the connecting element with either the tool engaging portion or the fitting body, or both, is to be designed less shear resistant than the fitting body by selecting the force engagement accordingly.


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patent: U9 310556 (1993-11-01), None
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