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

1. 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 a plurality of pairs of projecting elements ( 25 ) and of corresponding holes ( 26 ) in which the projecting elements ( 25 ) can be inserted, 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 ),

wherein during the insertion step each projecting element ( 25 ) is inserted in the corresponding hole ( 26 ),

wherein during the constraining step the first body ( 17 ) is irremovably constrained to the second body ( 18 ) by plastically deforming each projecting element ( 25 ) to prevent each projecting element ( 25 ) from being extracted from the corresponding hole ( 26 ) in which said projecting element ( 25 ) is inserted,

wherein the insertion step occurs by inserting the supporting portion ( 20 ) into the housing ( 14 ) along a line of insertion,

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 at the end of insertion each projecting element ( 25 ) has a coupling portion ( 27 ) which is at least partly in a different position along the line of insertion relative to the coupling portion ( 27 ) of at least one projecting element ( 25 ) of another pair.

2. The method according to claim 1 , wherein, once the insertion step is complete, at least two projecting elements ( 25 ) have the coupling portion ( 27 ) substantially in the same position along the line of insertion.

3. The method according to claim 1 , wherein, once the insertion step is complete, each projecting element ( 25 ) comprises an end portion ( 37 ) projecting from the corresponding hole ( 26 ).

4. The method according to claim 3 , wherein, during the constraining step, the end portion ( 37 ) of each projecting element ( 25 ) is plastically deformed by riveting.

5. 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.

6. The method according to claim 5 , wherein the sealing step is carried out by at least partly filling the housing ( 14 ) with a polymeric material ( 38 ).

7. The method according to claim 6 , wherein the sealing step is carried out by filling an empty space ( 34 ) delimited by the first body ( 17 ) and by the second body ( 18 ) at a mouth ( 30 ) of the housing ( 14 ) through which the supporting portion ( 20 ) is inserted in the housing ( 14 ) during the insertion step.

8. The method according to claim 6 , wherein, once the sealing step is complete, the polymeric material ( 38 ) at least partly encompasses the at least one plastically deformed projecting element ( 25 ).

9. 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 ).

10. The method according to claim 9 , wherein the step of taking the second body ( 18 ) is preceded by a step of making the second body ( 18 ) which in turn comprises a step of molding the second body ( 18 ) with a plastic material during which the at least one projecting element ( 25 ) and/or hole ( 26 ) is made.

11. 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 ).

12. A detection device ( 2 ) according to claim 11 , 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 ).

13. A pneumatic actuator ( 1 ) comprising a detection device ( 2 ) according to claim 11 .

14. 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 ).

15. A pneumatic actuator ( 1 ) comprising a detection device ( 2 ) according to claim 14 .