Method for making a detection device for detecting the position of a movable rod of a pneumatic actuator and detection device obtainable with that method

A method for making a detection device (2) for detecting a position of a movable rod (4) of a pneumatic actuator (1), comprising the operating steps of:

• taking a first body (17) comprising a connecting portion (19), a supporting portion (20) connected to the connecting portion (19), an electrical connector (21) associated with the connecting portion (19) and which in use allows electrical connection of the detection device (2) to a control unit, a magnetic field detection sensor (15) positioned on the supporting portion (20) and electrical connecting means (22) for electrically connecting the electrical connector (21) to the detection sensor (15);
• taking a second body (18) comprising a housing (14) in which the supporting portion (20) can be inserted;
• inserting the supporting portion (20) and the detection sensor (15) positioned on the supporting portion (20) into the housing (14);
• irremovably constraining the first body (17) to the second body (18);
• wherein the first body (17) and the second body (18) comprise, one at least one projecting element (25) and the other at least one corresponding hole (26) in which the projecting element (25) can be inserted,
• wherein during the insertion step the projecting element (25) is inserted in the hole (26), and
• wherein during the constraining step the first body (17) is irremovably constrained to the second body (18) by plastically deforming the projecting element (25) to prevent the projecting element (25) from being extracted from the hole (26) in which the projecting element (25) is inserted,
• wherein, after the constraining step, a step of fluid-tight sealing of the housing (14) of the second body (18) is carried out.

A method for making a detection device (2) for detecting a position of a movable rod (4) of a pneumatic actuator (1), comprising the operating steps of:

• taking a first body (17) comprising a connecting portion (19), a supporting portion (20) connected to the connecting portion (19), an electrical connector (21) associated with the connecting portion (19) and which in use allows electrical connection of the detection device (2) to a control unit, a magnetic field detection sensor (15) positioned on the supporting portion (20) and electrical connecting means (22) for electrically connecting the electrical connector (21) to the detection sensor (15);
• taking a second body (18) comprising a housing (14) in which the supporting portion (20) can be inserted;
• inserting the supporting portion (20) and the detection sensor (15) positioned on the supporting portion (20) into the housing (14);
• irremovably constraining the first body (17) to the second body (18);
• wherein the first body (17) and the second body (18) comprise, one at least one projecting element (25) and the other at least one corresponding hole (26) in which the projecting element (25) can be inserted,
• wherein during the insertion step the projecting element (25) is inserted in the hole (26), and
• wherein during the constraining step the first body (17) is irremovably constrained to the second body (18) by plastically deforming the projecting element (25) to prevent the projecting element (25) from being extracted from the hole (26) in which the projecting element (25) is inserted,
• wherein the step of taking the first body (17) is preceded by a step of making the first body (17) which in turn comprises the steps of:
• taking a metal shaped element (39) formed by at least two elongate parts (40) which are connected to one another,
• overmolding the metal shaped element (39) with a plastic material, forming at least the connecting portion (19), the supporting portion (20) connected to the connecting portion (19) and the at least one projecting element (25) and/or hole (26),
• separating the at least two elongate parts (40) of the overmolded metal shaped element (39),
• taking the detection sensor (15), positioning the detection sensor (15) on the supporting portion (20) and electrically connecting the detection sensor (15) to the at least two elongate parts (40) of the metal shaped element (39), the at least two elongate parts (40) constituting the electrical connector (21) and the electrical connecting means (22).

A detection device (2) for detecting a position of a movable rod (4) of a pneumatic actuator (1), comprising:

• a first body (17) comprising a connecting portion (19), a supporting portion (20) connected to the connecting portion (19), an electrical connector (21) associated with the connecting portion (19) and which in use allows electrical connection of the detection device (2) to a control unit, a magnetic field detection sensor (15) positioned on the supporting portion (20) and electrical connecting means (22) for electrically connecting the electrical connector (21) to the detection sensor (15);
• a second body (18) comprising a housing (14) in which the supporting portion (20) and the magnetic field detection sensor (15) positioned on the supporting portion (20) are inserted;
• wherein the first body (17) and the second body (18) comprise a plurality of pairs of projecting elements (25) and of corresponding holes (26), the projecting element (25) and the hole (26) of each pair being part, one of the first body (17) and the other of the second body (18), each projecting element (25) being inserted in the corresponding hole (26) and being plastically deformed to prevent each projecting element (25) from being extracted from the corresponding hole (26) in which said projecting element (25) is inserted, whereby the first body (17) is irremovably constrained to the second body (18);
• wherein for each pair of projecting element (25) and hole (26) there is a coupling portion (27) of the projecting element (25) inserted in the hole (26);
• and
• wherein the coupling portion (27) of one projecting element (25) is at a different height, relative to the bottom of the housing (14) of the second body (18), compared with the coupling portion (27) of at least one other projecting element (25).

A detection device (2) for detecting a position of a movable rod (4) of a pneumatic actuator (1), comprising:

• a first body (17) comprising a connecting portion (19), a supporting portion (20) connected to the connecting portion (19), an electrical connector (21) associated with the connecting portion (19) and which in use allows electrical connection of the detection device (2) to a control unit, a magnetic field detection sensor (15) positioned on the supporting portion (20) and electrical connecting means (22) for electrically connecting the electrical connector (21) to the detection sensor (15);
• a second body (18) comprising a housing (14) in which the supporting portion (20) and the magnetic field detection sensor (15) positioned on the supporting portion (20) are inserted;
• wherein the first body (17) and the second body (18) comprise, one at least one projecting element (25) and the other at least one corresponding hole (26);
• wherein the projecting element (25) is inserted in the hole (26) and is plastically deformed to prevent the projecting element (25) from being extracted from the hole (26) in which the projecting element (25) is inserted, whereby the first body (17) is irremovably constrained to the second body (18),
• wherein the housing (14) of the second body (18) is at least partly filled with a polymeric material (38) that fluid-tight seals the housing (14) of the second body (18),
• wherein the polymeric material (38) at least partly encompasses the at least one plastically-deformed projecting element (25).