Electrical switch

Patent metadata

Field	Value
Publication number	US-11043339-B2
Application number	US-202016820157-A
Country	US
Kind code	B2
Filing date	Mar 16, 2020
Priority date	Sep 15, 2017
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

The electrical switch includes a first and a second fixed contact, and a rotatable knife contact including at least one pair of blades being flexibly connected to each other and rotating around a rotational axis. A third fixed contact is positioned on an opposite side of the rotational axis in relation to the adjacent first and second fixed contact and a middle portion of the rotatable knife contact is electrically connected to the third fixed contact. The rotatable knife contact connects in a first switching position the first fixed contact and in a second switching position the second fixed contact to the third fixed contact.

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 rotational axis of the rotatable knife contact is positioned in a middle portion of the rotatable knife contact in respect of a longitudinal direction of the rotatable knife contact,
a third fixed contact is 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, wherein
the rotatable knife contact is permanently electrically connected from the middle portion to the third fixed contact in all positions of the rotatable knife contact,
the rotatable knife contact is rotatable between a first switching position in which a first outer end of the rotatable knife contact makes contact to the first fixed contact so that an electrical connection is formed between the first fixed contact and the third fixed contact and a second switching position in which a second opposite outer end of the rotatable knife contact makes contact to the second fixed contact so that an electrical connection is formed between the second fixed contact and the third fixed contact,
the permanent electrical connection between the third fixed contact and the middle portion of the rotatable knife contact is realized with at least one braided cable.

2. The electrical switch according to claim 1 , 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 a first outer end of the blades leads to a decrease of a distance between a second outer end of the blades and vice a versa.

3. The electrical switch according to claim 2 , wherein the pivot point is formed between two opposite, against each other seated protruded portions of the middle portion of each blade in the pair of blades, a spring constructions being attached to an 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.

4. The electrical switch according to claim 3 , wherein an outwardly protruding area is provided on an 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, or an outwardly protruding area is provided on opposite outer surfaces of the contact portion of the first and the second fixed contact.

5. The electrical switch according to claim 4 , wherein a roughened area is provided on opposite outer surfaces of a 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 or the second fixed contact is formed through the roughened area and the outwardly protruding area at the end of the switching event.

6. The electrical switch according to claim 1 , wherein a first contact pin is provided in the contact portion of the first and the second fixed contact, and a second contact pin is provided at outer ends of the blades in the pair of blades of the rotatable knife contact, wherein the second contact pin passes over the first contact pin in the switching event.

7. The electrical switch according to claim 6 , 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.

8. The electrical switch according to claim 6 , wherein the first and the second fixed contact as well as the blades in the rotatable knife contact are of a first electrically conductive material composition, the first and the second contact pin are of a second electrically conductive material composition, which is different from the first material composition.

9. The electrical switch according to claim 1 , wherein the electrical switch comprises a housing, wherein the first, the second and the third fixed contact are fixedly arranged in the housing and the rotatable knife contact is arranged to be rotatable around the rotational axis in the housing.

10. The electrical switch according to claim 9 , wherein the housing comprises 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.

11. The electrical switch according to claim 9 , wherein 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.

12. The electrical switch according to claim 9 , wherein the third fixed contact is formed of a T-shaped or at least one L-shaped body having a horizontal arm seated against an inner support surface in the housing, and a vertical arm protruding out from the housing.

13. The electrical switch according to claim 12 , wherein the housing comprises a measurement aperture at a position of the horizontal arm of the third fixed contact, a temperature of the horizontal arm of the third fixed contact being measurable from the outside of the housing through the measurement aperture.

14. The electrical switch according to claim 12 wherein the middle portion of the rotatable knife contact is connected to the horizontal arm of the third fixed contact with at least one flexible braided cable.

15. The electrical switch according to claim 1 , wherein the third fixed contact is connected with a pivot connection to the middle portion of the rotatable knife contact.

16. The electrical switch according to claim 1 , wherein an outwardly protruding area is provided on an 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, or an outwardly protruding area is provided on opposite outer surfaces of the contact portion of the first and the second fixed contact.

17. The electrical switch according to claim 5 , wherein a first contact pin is provided in the contact portion of the first and the second fixed contact, and a second contact pin is provided at outer ends of the blades in the pair of blades of the rotatable knife contact, wherein the second contact pin passes over the first contact pin in a switching event.

18. The electrical switch according to claim 7 , wherein the first and the second fixed contact as well as the blades in the rotatable knife contact are of a first electrically conductive material composition, the first and the second contact pin are of a second electrically conductive material composition, which is different from the first material composition.

19. The electrical switch according to claim 10 , wherein the rotatable knife contact is supported on a rotatable roller, the roller comprising end portions being fitted into circular openings in the housing,

Assignees

• Abb Schweiz Ag

Inventors

• Kolmonen Rainer
• Rabb Patrik

Classifications

• H01H1/2041 Primary

  Rotating bridge · CPC title

• H01H19/46

  the operating part having three operative positions, e.g. off/star/delta · CPC title

• H01H73/045

  Bridging contacts · CPC title

• H01H9/36

  Metal parts · CPC title

• H01H2300/018

  Application transfer; between utility and emergency power supply · CPC title