Housing for a field device of automation technology

Patent metadata

Field	Value
Publication number	US-9752903-B2
Application number	US-201514969148-A
Country	US
Kind code	B2
Filing date	Dec 15, 2015
Priority date	Dec 22, 2014
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A housing for a field device of automation technology with a screwed connection, which connects a first housing part with an external thread with a second housing part with an internal thread. The screwed connection provides a transition impedance lessened for EMC disturbance signals. The reduction of the transition impedance is achieved by including in the screw thread a screw thread segment, in which a second screw thread type is designed in contrast to a first screw thread type located outside of the screw thread segment to provide a lessened transition impedance. Besides the basic provision that the screw thread is electrically conductive at least in corresponding portions, the second screw thread type can be differently embodied, in order to achieve the lessened transition impedance. This can occur, on the one hand, by providing the second screw thread type as round threads. However, other forms of embodiment of the screw thread segment are possible.

First claim

The invention claimed is:

1. A housing for a field device of automation technology, comprising: a first housing part with an external thread; and a second housing part with an internal thread, wherein: said external thread and said internal thread have a first screw thread type with a first thread side-form, said first screw thread type is embodied in such a manner that said external thread and said internal thread form a force interlocking, screwed connection, wherein the first screw thread type is a triangular or trapezoidal thread; said external thread and said internal thread are electrically conductive at least in corresponding portions of the surface; said external thread and/or said internal thread have/has at least one screw thread segment of at least one-fourth of a winding of a second screw thread type, which is compatible with said first screw thread type and which has a second thread side-form; and said second screw thread type is embodied in such a manner to reduce transition impedance from high-frequency electromagnetic disturbance signals between the two housing parts is lessened in comparison with said first screw thread type.

2. The housing as claimed in claim 1 , wherein:
for the case, in which said external thread and said internal thread have said screw thread segment, said two screw thread segments at least approximately coincide with one another in the screwed state.

3. The housing as claimed in claim 1 , wherein:
said first housing part or said second housing part is a housing lid.

4. The housing as claimed in claim 1 , wherein:
said first housing part and/or said second housing part are/is manufactured of a metal material.

5. The housing as claimed in claim 1 , wherein:
said first housing part and/or said second housing part are/is manufactured of at least one of the following: a synthetic material and a composite material.

6. The housing as claimed in claim 5 , wherein:
the corresponding portions of said surfaces of said internal thread and said external thread comprise a metallizing layer.

7. The housing as claimed in claim 1 , wherein:
said at least one screw thread segment of the at least one winding of said second screw thread type lie/lies in one of the end regions of said internal thread and/or said external thread.

8. The housing as claimed in claim 7 , wherein:
said first screw thread type has on said external thread a first outer radius, which is constant; and
said second screw thread type has on said external thread a first inner radius, which is constant;
said second screw thread type has on said external thread a second outer radius, which in at least one of the two end regions of the thread is identical to said first inner radius and which increases along said screw thread segment of the at least one winding with a fixed slope from said first inner radius on said first outer radius.

9. The housing as claimed in claim 7 , wherein:
said first screw thread type has on said internal thread a second inner radius, which is constant;
said second screw thread type has on said internal thread a third outer radius, which is constant; and
said second screw thread type has on said internal thread a fourth outer radius, which is in at least one of the two end regions of the thread identical to said third outer radius, and which fourth outer radius decreases along said screw thread segment of the at least one winding with a fixed slope from said third outer radius to said second inner radius.

10. The housing as claimed in claim 1 , wherein:
said second screw thread type is a round thread.

11. The housing as claimed in claim 1 , wherein:
said second thread side-form is embodied aymmetrically in such a manner that it has a first side, which lies in front in the screwing direction and which is rounded, and a second side, which lies behind in the screwing direction and which is flat.

Assignees

• Endress Hauser Gmbh Co Kg

Inventors

• Ingenhoven Benjamin
• Blodt Thomas

Classifications

• G01D11/24 Primary

  Housings {; Casings for instruments} · CPC title

• G01K1/08

  Protective devices, e.g. casings · CPC title

• G01K1/14

  Supports; Fastening devices; Arrangements for mounting thermometers in particular locations · CPC title