# US 9,752,903 B2 · Housing for a field device of automation technology > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,903 B2 - Document ID: US9752903B2 - Status: Granted - Kind: B2 - Application number: 14/969,148 - Filed: 2015-12-15 - Published: 2016-06-23 - Granted: 2017-09-05 - Earliest claimed: 2014-12-22 - Assignees: Endress + Hauser GmbH + Co. KG - Applicants: Endress + Hauser GmbH + Co. KG - Inventors: Benjamin Ingenhoven; Thomas Blodt - Web page: https://patentgrep.com/patent/US9752903B2 ## CPC - G01D 11/24: Housings {; Casings for instruments} - G01K 1/08: Protective devices, e.g. casings - G01K 1/14: Supports; Fastening devices; Arrangements for mounting thermometers in particular locations - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00) ## 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. ## Claims ### Claim 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. ### Claim 2 (depends on 1) 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. ### Claim 3 (depends on 1) The housing as claimed in claim 1, wherein: said first housing part or said second housing part is a housing lid. ### Claim 4 (depends on 1) 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. ### Claim 5 (depends on 1) 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. ### Claim 6 (depends on 5) 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. ### Claim 7 (depends on 1) 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. ### Claim 8 (depends on 7) 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. ### Claim 9 (depends on 7) 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. ### Claim 10 (depends on 1) The housing as claimed in claim 1, wherein: said second screw thread type is a round thread. ### Claim 11 (depends on 1) 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.