Electrical switch

Patent metadata

Field	Value
Publication number	US-11037739-B2
Application number	US-202016814176-A
Country	US
Kind code	B2
Filing date	Mar 10, 2020
Priority date	Sep 15, 2017
Publication date	Jun 15, 2021
Grant date	Jun 15, 2021

Abstract

The electrical switch includes two fixed contacts and a rotatable knife contact having a rotational axis and including at least one longitudinal pair of blades flexibly connected to each other. The two fixed contacts as well as the blades in the rotatable knife contact are of a first electrically conductive material composition. The first and the second fixed contact includes a first contact pin and outer ends in the blades in the rotatable knife contact includes a second contact pin. The first contact pin and the second contact pin are of a second electrically material composition, which is different from the first material composition. The first contact pin and the second contact pin pass over each other during a switching event.

First claim

The invention claimed is:

1. An electrical switch comprising:
a first fixed contact,
a second fixed contact,
a rotatable knife contact having a rotational axis and comprising at least one longitudinal pair of blades flexibly connected to each other, wherein the blades form, in a switching event, contact with contact portions of the first and/or the second fixed contact,
the first fixed contact and the second fixed contact as well as the blades in the rotatable knife contact being of a first electrically conductive material composition,
the rotational axis of the rotatable knife contact is positioned in a middle portion of the rotatable knife contact,
the contact portion of the first and the second fixed contact comprises a first contact pin positioned in a first recess in the contact portion,
opposite outer ends of the blades in the rotatable knife contact comprises a second contact pin positioned in a second recess in the blade,
the first contact pin and the second contact pin being of a second electrically conductive material composition, the second electrically conductive material composition being different from the first electrically conductive material composition and comprising at least one material that has a higher restivity to the wearing effect of an arc acting between the rotatable knife contact and the first or second fixed contact in the switching event compared to any material in the first electrically conductive material composition,
the second contact pin passing over the first contact pin in the switching event so that when the rotatable knife contact reaches an end position on the first or the second fixed contact there is no contact between the first contact pin and the second contact pin.

2. The electrical switch according to claim 1 , wherein the second material composition comprises at least one material that has a higher resistivity to the wearing effect of an arc acting between the fixed contacts and the rotatable knife contact in the switching event compared to any of the materials in the first material composition.

3. The electrical switch according to claim 1 , wherein the second contact pin and the first contact pin overlap each other only partly when the second contact pin passes over the first contact pin in the switching event.

4. The electrical switch according to claim 3 , wherein the first contact pin extends on opposite surfaces of the contact portions of the first and the second fixed contact.

5. The electrical switch according to claim 4 , wherein the portions of the first contact pin extending on opposite surfaces of the first and the second fixed contact are connected with a curved portion extending over an edge of the contact portion.

6. The electrical switch according to claim 5 , wherein the second contact pin extends on opposite surfaces of the blade.

7. The electrical switch according to claim 6 , wherein portions of the second contact pin extending on opposite surfaces of the blade are connected with a curved portion extending over the edge of the blade.

8. The electrical switch according to claim 1 , wherein an edge of the contact portion in the first and the second fixed contact further comprises a protruding nose forming a first contact with the rotatable knife contact in the switching event.

9. The electrical switch according to claim 8 , wherein an outwardly protruding area is provided on an inner surface of each blade at the distance from an outer tip of the blade in the pair of blades of the rotatable knife contact, or an outwardly protruding area is provided on opposite outer surfaces of the contact portion of the first and the second fixed contact.

10. The electrical switch according to claim 9 , wherein a roughened area is provided on opposite outer surfaces of the connection portion of the first and the second fixed contact, or a roughened area is provided on the inner surface of each blade at a distance from an outer tip of the blade in the pair of blades of the rotatable knife contact, wherein a continuous contact between the rotatable knife contact and the first and the second fixed contact is formed through the roughened area and the outwardly protruding area at the end of the switching event.

11. The electrical switch according to claim 1 , wherein the electrical switch comprises a third fixed contact being positioned on an opposite side of the rotational axis of the rotatable knife contact in relation to the first and the second fixed contact being adjacent to each other, a middle portion of the rotatable knife contact being electrically connected to the third fixed contact in all positions of the rotatable knife contact, the rotatable knife contact being rotatable between a first switching position in which a connection portion of the first fixed contact is received between a first outer end of the blades and a second switching position in which a connection portion of the second fixed contact is received between a second outer end of the blades.

12. The electrical switch according to claim 11 , wherein the three fixed contacts and the rotatable knife contact are positioned in a housing comprising a first side wall and a second side wall being opposite to and spaced apart from the first side wall in a longitudinal direction of the housing, a connection portion of the first and the second fixed contact passing through the first side wall and the third fixed contact passing through the second side wall.

13. The electrical switch according to claim 12 , the rotatable knife contact is supported on a rotatable roller, the roller comprising end portions being fitted into circular openings in the housing, wherein the roller and thereby also the rotatable knife contact become rotatable in respect of the housing.

14. The electrical switch according to claim 13 , wherein the flexible connection between the blades in each pair of blades in the rotatable knife contact is realized through a pivot point formed between a middle portion of the blades allowing the blades to take a V-shape so that an increase of the distance between the first outer end of the blades leads to a decrease of a distance between the second outer end of the blades and vice a versa.

15. The electrical switch according to claim 14 , wherein the pivot point is formed between a first protruded portion in a first blade of each pair of blades and a second protruded portion in a second blade of each pair of blades, the first protruded portion and the second protruded portion being positioned in a middle portion of the respective first or second blade, the first protruded portion seating against the second protruded portion, a spring construction being attached to the outer surface of each blade in the pair of blades in order to keep the blades substantially parallel when no force is acting on the blades.

16. The electrical switch according to claim 1 , wherein the first contact pin extends on opposite surfaces of the contact portions of the first and the second fixed contact.

17. The electrical switch according to claim 1 , wherein the second contact pin extends on opposite surfaces of the blade.

18. The electrical switch according to claim 2 , wherein the second contact pin and the first contact pin overlap each other only partly when the second contact pin passes over the first contact pin in a switching event.

19. The electrical switch according to claim 18 , wherein the first contact pin extends on opposite surfaces of the contact portions of the first and the second fixed contact.

20. The electrical switc

Assignees

• Abb Schweiz Ag

Inventors

• Kolmonen Rainer
• Rabb Patrik

Classifications

• H01H9/38 Primary

  Auxiliary contacts on to which the arc is transferred from the main contacts (using arcing-horns H01H9/46) · CPC title

• H01H1/04

  Co-operating contacts of different material · CPC title

• H01H1/365

  Bridging contacts · CPC title

• H01H9/02

  Bases, casings, or covers (accommodating more than one switch or a switch and another electrical component H02B1/26) · CPC title

• H01H1/44

  with resilient mounting · CPC title