Microswitch

Abstract

A microswitch (10) comprising a housing (11) formed by at least two half-shells (35, 36) which engage with each other at respective mutually facing and overlapping peripheral edges to define a compartment (12) which accommodates a first electrical contact (15), a second electrical contact (16) and a contact element (19) movable relative to the first electrical contact (15) and the second electrical contact (16), the two half-shells (35, 36) being in contact with the first electrical contact (15) and the second electrical contact (16). 36) are stably connected together by at least part of the respective peripheral edges being welded to one another.

Description

Technical Field

[0001] The utility model relates to a microswitch, which is used to open and close a circuit for industrial facilities or any machine or device, in response to an externally applied pressure on the microswitch. Background Art

[0002] Known microswitches generally include a housing that defines an internal compartment, in which a movable electrical contact and two fixed electrical contacts connected to corresponding external circuits are arranged.

[0003] In addition, known microswitches also include a drive head provided outside the housing, which is adapted to receive mechanical pressure to be transmitted to the movable electrical contact and move it between the fixed electrical contacts, opening or closing the circuit to which the latter are connected.

[0004] Generally, the housing of a known microswitch includes two housings fixed to each other by screws, rivets, bolts or other similar fastening elements, or by means of a joint obtained by shape coupling.

[0005] In addition, in some cases, it is necessary to seal the compartment inside the housing to prevent water, dust or the like from reaching the electrical contacts located inside and causing their failure.

[0006] For this purpose, known microswitches generally include a gasket arranged between the two housings of the housing to prevent water, dust or anything from leaking through the contact area between the two housings into the internal compartment of the housing.

[0007] The disadvantages of known microswitches are represented by the fact that, although they include gaskets, it is not always possible to ensure a completely sealed closure of the internal compartment of the housing. In fact, during the assembly operation of the microswitch, typically, the gasket cannot be fully placed in its seat, thus preventing the two housings of the housing from being properly fixed together.

[0008] Another disadvantage lies in the fact that the screws, rivets, bolts or other fastening elements of the two housings, or even the shape coupling itself between the two housings, occupy a large volume and thus limit the available volume of the compartment inside the housing.

[0009] This disadvantage limits the size of the electrical contacts accommodated in the internal compartment of the housing and thus also limits the current they can withstand, effectively limiting the applications in which the microswitch can be used.

[0010] This problem is exacerbated in the case where a gasket is also provided between the two housings of the housing. In fact, the housing for the gasket and the gasket itself occupy a part of the volume of the internal compartment of the housing, still limiting the available volume for accommodating the electrical contacts. Summary of the Utility Model

[0011] The object of the present utility model is to implement a microswitch and its related manufacturing process, which can overcome the above-mentioned disadvantages of the existing microswitches.

[0012] A specific object of the present utility model is to implement a microswitch having a ratio close to one between the volume of the internal compartment of the housing and the overall volume of the microswitch.

[0013] Another object of the present utility model is to implement a microswitch for applications where a very high current is expected.

[0014] Another object of the present utility model is to implement a microswitch with simple manufacturing, having a compact size and a highly sealed internal compartment of the housing.

[0015] Another object of the present utility model is to develop a method for manufacturing a microswitch that allows reducing the fixing error between the housings.

[0016] These objects, as well as other objects that become more apparent hereinafter, are achieved by a microswitch comprising a housing formed by at least two half-shells, said half-shells facing each other and overlapping to define a compartment for receiving a first electrical contact, a second electrical contact, and a contact element movable relative to said first electrical contact and said second electrical contact, and wherein said at least two half-shells are stably connected together by welding at least a part of their respective peripheral edges.

[0017] In this way, since there are no external fastening elements or shape couplings, there will also be no elements that will occupy the internal space of the compartment, thus allowing more space available for the contacts.

[0018] As a result, compared with the known solutions, the contacts can have parts with an increased width, but it is not necessary to increase the overall size of the microswitch.

[0019] Therefore, the microswitch simultaneously maintains a relatively small size and a high degree of construction simplicity, and can also be used in applications involving currents with relatively high amperage.

[0020] Advantageous embodiments of the microswitch are obtained according to the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features and advantages of the present utility model will become more apparent from the detailed description of a preferred but non-exclusive embodiment of the microswitch, with reference to the drawings, which illustrate, by way of non-limiting example, embodiments of the microswitch, wherein:

[0022] Figure 1 is an axonometric view of a microswitch according to an embodiment of the present utility model;

[0023] Figure 2 is Figure 1 a view of a part of a microswitch;

[0024] Figure 3 , Figure 4 and Figure 5 are sectional views of the microswitch according to section planes III, IV, and V, respectively; Figure 1 of the microswitch;

[0025] Figure 6 is Figure 1 a sectional view of a detail of the microswitch;

[0026] Figure 7 is an isometric view of the microswitch according to an embodiment of the present invention;

[0027] Figure 8 is Figure 7 a view of a part of the microswitch. Detailed Description of the Invention

[0028] The microswitch according to the present invention, generally designated 10, is designed to be connected to one or more external circuits and to open or close the latter in response to pressure received from an external component.

[0029] Specifically, referring to Figure 1 , the microswitch 10 includes a housing 11 that defines an internal compartment 12 in which two or more electrical contacts are arranged and adapted to be connected to the one or more circuits described above.

[0030] In this example, the microswitch 10 includes a first electrical contact 15 and a second electrical contact 16, which are fixed within the compartment 12 in the illustrated configuration.

[0031] Each of the first electrical contact 15 and the second electrical contact 16 is associated with a respective connection terminal 15', 16' to permit its connection to a respective external circuit.

[0032] By way of example, the connection terminals 15', 16' may be of the crimp type, screw type, cable lug type, or other similar types.

[0033] Within the compartment 12 there is also a contact element 19 that is movable between a first position and a second position relative to the first electrical contact 15 and the second electrical contact 16 and is adapted to operate on the first electrical contact 15 and the second electrical contact 16 to open or close the circuit to which they are connected.

[0034] The contact element 19 is also associated with a connection terminal 19' to electrically connect it to an external circuit.

[0035] In Figure 3In the example, the contact element 19 includes a lamina 20 having a first end 21 fixed to the connection terminal 19' and a second end 22 disposed between the first electrical contact 15 and the second electrical contact 16.

[0036] In this case, in the first position, the second end 22 is in contact with the first electrical contact 15, while in the second position, the second end 22 is in contact with the second electrical contact 16.

[0037] The lamina 20 includes two outer portions 25 connecting the first end 21 to the second end 22 and an inner portion 26 extending from the second end 22 and blocked by the adjacent element 23 integral with the housing 11. When pressure is applied to the lamina 20, the inner portion 26 elastically deforms relative to the outer portions 25 to facilitate the snap movement of the second end 22 between the first electrical contact 15 and the second electrical contact 16.

[0038] Furthermore, in this structure, when no pressure is applied to the lamina 20, the second end 22 of the lamina 20 can be stably held on one of the first electrical contact 15 and the second electrical contact 16. In this example, when no pressure is applied to the lamina 20, its second end 22 is held on the first electrical contact 15.

[0039] The microswitch 10 further includes a drive device 30 adapted to receive pressure from a member external to the microswitch 10 and operate on the contact element 19 to move it from the first position to the second position and vice versa.

[0040] In this case, the drive device 30 includes a drive head 31 outside the housing 11 and an actuator pin 32 associated with the drive head 31 and is adapted to apply pressure to the lamina 20 to move its second end 22 from the first position to the second position.

[0041] In this case, when the lamina 20 is pressed by the actuator pin 32, the elastic energy stored in the deformed inner portion 26 of the lamina 20 allows for the rapid snap movement of the second end 22.

[0042] The drive head 31 is slidably fixed to the housing 11, and preferably, there is a first sealing device between the drive head 31 and the housing 11, which is adapted to prevent the penetration of water or dirt, or generally a liquid or an external body, inside the housing 11, especially inside the compartment 12. Preferably, the drive device is movable along the operating direction X, and even more preferably, the drive head 31 slides along the operating direction X.

[0043] As an example, the first sealing device may include a collar 33 fixed to the housing 11 by screws, joints, etc. and surrounding the drive head 31, which also serves as a guide.

[0044] Similarly, a second sealing device is preferably also present between the actuator pin 32 and the housing 11. As an example, the second sealing device may include a flexible bellows 34 fixed to the housing 11 and the actuator pin 32.

[0045] The housing 11 includes at least two half-shells 35, 36, each half-shell 35, 36 having respective peripheral edges 37 and being designed to be arranged in a facing and overlapping position with each other to define the compartment 12.

[0046] Preferably, the two half-shells 35, 36 are arranged in a facing and overlapping position with respect to a joining plane P perpendicular to the operating direction X.

[0047] Even more preferably, the peripheral edges 37 of the two half-shells 35, 36 are substantially located on the joining plane P or in a plane parallel to the joining plane P.

[0048] In this way, ultrasonic welding is more effective for joining the two half-shells 35, 36 because the energy of the ultrasonic vibrations transmitted to the two half-shells 35, 36 during the welding operation is constant throughout the entire development of the peripheral edges 37 of the two half-shells 35, 36.

[0049] Furthermore, even more preferably, each half-shell 35, 36 includes outer surfaces 53, 54 that are substantially parallel to the joining plane P ( Figure 7 and 8 ). In this way, for each point of the outer surfaces 53, 54, the distance between each point of the outer surfaces 53, 54 and the joining plane P is substantially constant. This feature also contributes to the ultrasonic welding operation of the two half-shells 35, 36 because it allows the welding member to be arranged at an ultrasonic (ultrasonic horn) parallel to the joining plane P and thus parallel to the peripheral edges 37.

[0050] According to a particular aspect of the present utility model, the two half-shells 35, 36 will be stably connected together by welding, which will preferably be ultrasonic welding.

[0051] In a particularly preferred manner, the welding of the peripheral edges 37 will be carried out throughout the entire development.

[0052] Advantageously, this allows a sealed coupling between the two half-shells 35, 36 even in the absence of gaskets or other additional sealing devices.

[0053] In addition, this configuration allows the two half-shells 35, 36 to be joined without using fixing elements such as screws, rivets or others, and without providing a specific shape or interlocking coupling between them.

[0054] In a preferred embodiment, each of the first electrical contact 15 and the second electrical contact 16 includes at least two contact areas that are independent of each other. In particular, the contact areas are different and physically separated from each other.

[0055] Thanks to the fact that the two half-shells 35, 36 are connected by ultrasonic welding, such a configuration is possible.

[0056] In fact, the absence of fastening elements between the two half-shells 35, 36 and the gasket allows the compartment 12 inside the housing 11 to have a very large volume, suitable for accommodating the large first electrical contact 15 and the second electrical contact 16.

[0057] Furthermore, thanks to this configuration, the reliability of the contact between the thin sheet 20 and the first electrical contact 15 and the second electrical contact 16 is also improved.

[0058] In particular, the presence of two different and separate contact areas for each of the first electrical contact 15 and the second electrical contact 16 reduces the risk of unstable or incomplete alignment with the contact element 19.

[0059] Advantageously, in this way, the microswitch 10 of the present utility model can have a compact size and at the same time emit a high value current even higher than 5A, either DC or AC.

[0060] In the current example, each of the first electrical contact 15 and the second electrical contact 16 includes a respective plate 40, 41, on which at least one conductive pad is fixed.

[0061] Preferably, two or more independent conductive pads 42, 43 are fixed to each plate 40, 41. In this way, each of the first electrical contact 15 and the second electrical contact 16 includes at least two independent contact areas defined by the conductive pads 42, 43.

[0062] Furthermore, the second end 22 of the thin sheet 20 also includes at least two mutually independent contact areas.

[0063] This feature also helps to transmit a high value current, even exceeding 5A, either DC or AC.

[0064] In fact, the two mutually independent contact areas reduce the risk of unstable contact or adhesion between the thin sheet 20 and the first electrical contact 15 and the second electrical contact 16.

[0065] In this case, the second end 22 of the thin sheet 20 includes at least two pairs of conductive pads 44, 45. Specifically, two higher conductive pads 44 are designed to contact a pair of conductive pads 42 of the first electrical contact 15, and two lower conductive pads 45 are designed to contact a pair of conductive pads 43 of the second electrical contact 16.

[0066] Preferably but not necessarily, the cross-sectional area S( Figure 6 ) of each of the conductive pads 42, 43, 44, 45 is greater than 3.5 mm 2 .

[0067] It should be noted that the cross-sectional area S is the maximum cross-sectional area of the conductive pads 42, 43, 44, 45 with respect to a cross-sectional plane parallel to the surface of the sheet 20 on which the conductive pads 42, 43, 44, 45 are located.

[0068] Thanks to the fact that the two half-shells 35, 36 are connected by ultrasonic welding, this configuration is also possible.

[0069] In fact, the absence of fastening elements between the two half-shells 35, 36 and the gasket allows the compartment 12 in the housing 11 to have a very large volume, suitable for accommodating the second end 22 of the sheet 20 with high dimensions.

[0070] Advantageously, this feature also allows the microswitch 10 of the present utility model to have a compact size and, at the same time, to transmit a high value of current, even greater than 5 A, or DC and AC.

[0071] It will be readily understood by those skilled in the art that in the present example, the cross-sectional area S of the conductive pads 42, 43, 44, 45 is circular and can be of different shapes, such as square, polygonal, or defined by any combination of straight or curved parts, without departing from the scope of protection of the present utility model.

[0072] Preferably, the microswitch 10 further includes fixing means adapted to allow the microswitch 10 to be fixed to an industrial machine or installation. In Figure 7 and 8 the example of, the fixing means are through-fixing holes 51, 52.

[0073] The through-fixing holes 51, 52 are advantageously and conveniently obtained on one of the two half-shells 35, 36. Preferably, the through-fixing holes 51, 52 are advantageously and conveniently obtained only on one of the two half-shells 35, 36. In particular, the through-fixing holes 51, 52 pass only through a single half-shell 36 and have corresponding central axes parallel to the joining plane P. This is advantageous because in use, the fixing screws inserted into the through-fixing holes 51, 52 pass only through a single half-shell 36 and do not contact the peripheral edge 37 designed to be welded. This increases the resistance of the microswitch 10 of the present utility model because the force transmitted by the fixing screws to the half-shell 36 is applied in a region of the half-shell 36 without a continuous solution.

Claims

1. A micro switch, the micro switch (10) comprising a housing (11), the housing (11) being formed by at least two half shells (35, 36), the at least two half shells (35, 36) being joined to each other at respective peripheral edges (37) facing and overlapping each other to define a compartment (12), the compartment (12) accommodating a first electrical contact (15), a second electrical contact (16) and a contact element (19) movable relative to the first electrical contact (15) and the second electrical contact (16); It is characterized in that The at least two half shells (35, 36) are stably connected together by at least partially welding the respective peripheral edges (37) to each other.

2. The micro switch according to claim 1, characterized in that: The at least two half shells (35, 36) are stably joined together along the entire development of the peripheral edge (37) by the welding and without further fixing and / or joining and / or form coupling between the respective peripheral edges (37).

3. The micro switch according to claim 1 or 2, characterized in that: The respective peripheral edges (37) of the at least two half-shells (35, 36) are in direct contact with each other without the presence of a gasket.

4. The micro switch according to claim 1, characterized in that: The welding is ultrasonic welding.

5. The micro switch according to claim 1, characterized in that: The contact element (19) is movable in the compartment (12), the micro switch (10) comprising a drive device (30) adapted to move the contact element (19) between at least a first position and a second position, wherein The first position is in electrical continuity with the first electrical contact (15) and the second position is in electrical continuity with the second electrical contact (16), or The first position is in electrical continuity with the second electrical contact (16) and the second position is in electrical continuity with the first electrical contact (15).

6. The micro switch according to claim 5, characterized in that: The drive device (30) is movable in an operating direction (X), and the at least two half shells (35, 36) are arranged in a mutually facing and overlapping position relative to a joint plane (P) perpendicular to the operating direction (X).

7. The micro switch according to claim 1, characterized in that: At least one of the first electrical contact (15) and the second electrical contact (16) comprises at least two distinct and separate contact areas adapted to maintain conductive continuity with each other through the contact element (19).

8. The micro switch according to claim 7, characterized in that: Each of the first electrical contact (15) and the second electrical contact (16) comprises two contact areas.

9. The micro switch according to claim 8, characterized in that: Each of the first electrical contact (15) and the second electrical contact (16) comprises a respective plate and a respective conductive pad, wherein the respective conductive pad is fixed to the respective plate so as to define the contact area.

10. The micro switch according to claim 5, characterized in that: The contact element (19) comprises a thin sheet (20), the thin sheet (20) having a first end (21) fixed to the housing (11) and a second end (22) arranged with two higher conductive pads (44), when the contact element (19) is in the first position, the two higher conductive pads (44) are placed in contact with the conductive pad (42) of the first electrical contact (15); when the contact element (19) is in the second position, the two lower conductive pads (45) are placed in contact with the conductive pad (43) of the second electrical contact (16).

11. The micro switch according to claim 10, characterized in that: The contact element (19) further comprises an abutment element (23) integral with the housing (11), the sheet (20) comprising two outer portions (25) connected to the first end (21) and the second end (22) and an inner portion (26) developing from the second end (22) and held in a deformed configuration by the abutment element (23).

12. The micro switch according to claim 10, characterized in that: The drive device (30) comprises a drive head (31) and an actuator pin (32), wherein the drive head (31) is located outside the housing (11), and the actuator pin (32) is associated with the drive head (31) and is suitable for applying pressure on the sheet (20), wherein the pressure is suitable for moving the second end (22) of the sheet (20) from the first position to the second position.

13. The micro switch according to claim 12, characterized in that: The microswitch also comprises sealing means (33, 34) associated with the drive means (30) and the housing (11) and adapted to avoid the penetration of liquids or foreign bodies into the compartment (12).

14. The micro switch according to claim 10, characterized in that: The surface of each of the two higher conductive pads (44), the two lower conductive pads (45), the conductive pad (42) of the first electrical contact (15), and the conductive pad (43) of the second electrical contact (16) is greater than 3.5 mm 2 .

15. The micro switch according to claim 6, characterized in that: At least one of the at least two half-shells (35, 36) comprises at least one through-going fixing hole (51, 52), the at least one through-going fixing hole (51, 52) having a central axis parallel to the joining plane (P).

16. The micro switch according to claim 6, characterized in that: At least one of the at least two half-shells (35, 36) comprises at least one outer surface (53, 54) parallel to the joining plane (P).

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