Longitudinal electromagnetic latching relay

• US 20040201440A1
• Filed: 04/14/2003
• Published: 10/14/2004
• Est. Priority Date: 04/14/2003
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Fong, Arthur, Wong, Marvin Glenn
• Granted Patent: US 6,838,959 B2
• Time in Patent Office: Days
• US Class Current: 335/78
• CPC Class Codes: H01H 2001/0042 Bistable switches, i.e. having two stable positions requiring only actuating energy for switching between them, e.g. with snap membrane or by permanent magnet
• CPC Class Codes: H01H 2029/008 using micromechanics, e.g. micromechanical liquid contact switches or [LIMMS]
• CPC Class Codes: H01H 29/28 with level of surface of contact liquid displaced by fluid pressure
• CPC Class Codes: H01H 50/005 using micromechanics
• CPC Class Codes: H01H 50/20 movable inside coil and substantially lengthwise with respect to axis thereof; movable coaxially with respect to coil
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49105 Switch making
• CPC Class Codes: Y10T 29/49147 Assembling terminal to base

Abstract

The present invention relates to an electrical relay in which a solid slug is moved within a channel and used to make or break an electrical connection. The solid slug is moved by electromagnets. In the preferred embodiment, the slug is wetted by a conducting liquid, such as liquid metal, that also adheres to wettable contact pads within the channel to provide a latching mechanism. The relay is amenable to manufacture by micro-machining techniques.

Claims

1. An electromagnetic relay, comprising:

a relay housing containing a switching channel;

a solid slug adapted to move within the switching channel;

a first contact located in the switching channel and having a surface wettable by a liquid;

a second contact located in the switching channel and having a surface wettable by a liquid;

a third contact located in the switching channel between the first and second contacts and having a surface wettable by a liquid;

an electrically conducting liquid in wetted contact with the solid slug;

a first electromagnetic actuator operable to move the solid slug to a first position where it is in wetted contact with the first and third contacts; and

a second electromagnetic actuator operable to move the solid slug to a second position where it is in wetted contact with the second and third contacts.

2. An electromagnetic relay in accordance with claim 1, wherein at least one of the first and second electromagnetic actuators comprises an electrical coil surrounding the switching channel.

3. An electromagnetic relay in accordance with claim 1, further comprising a pressure relief vent opening to and connecting the ends of the switching channel, the vent adapted to relieve pressure in the channel when the solid slug is moved.

4. An electromagnetic relay in accordance with claim 3, wherein the pressure-relief vent is sized and positioned to dampen motion of the solid slug.

5. An electromagnetic relay in accordance with claim 1, wherein the conducting liquid is a liquid metal.

6. An electromagnetic relay in accordance with claim 1, wherein the solid slug is magnetic.

7. An electromagnetic relay in accordance with claim 1, wherein the relay housing comprises:

a circuit substrate layer on which the first, second and third contacts are formed;

a cap layer; and

a switching layer, positioned between the circuit layer and the cap layer, in which the switching channel is formed.

8. An electromagnetic relay in accordance with claim 7, further comprising a pressure relief vent formed in the switching layer, the pressure relief vent opening to and connecting the ends of the switching channel.

9. An electromagnetic relay in accordance with claim 7, manufactured by a micro-machining.

10. An electromagnetic relay in accordance with claim 1, further comprising:

a first electrical connector electrically coupled to the first contact;

a second electrical connector electrically coupled to the second contact; and

a third electrical connector electrically coupled to the third contact.

11. An electromagnetic relay in accordance with claim 1, further comprising:

a first non-conducting tube positioned between the first contact and the third contact;

a second non-conducting tube positioned between the second contact and the third contact;

wherein the first, second and third contacts and the first and second non-conducting tubes enclose and form the switching channel, the first and second contacts forming the ends of the switching channel.

12. An electromagnetic relay in accordance with claim 11, wherein the first electrical coil surrounds the first non-conducting tube and the second electrical coil surrounds the second non-conducting tube.

13. An electromagnetic relay in accordance with claim 11, wherein the first and second non-conducting tubes are made of glass.

14. A method for switching an electrical circuit between a first contact and a second contact in a electromagnetic relay having solid slug wetted by a conducting liquid, the method comprising:

if the electrical circuit is to be completed;

energizing a first electromagnetic actuator to move the solid slug along a switching channel to a first position where it is in wetted contact with the first electrical contact and the second electrical contact; and

if the electrical circuit is to be broken;

energizing a second electromagnetic actuator to move the solid slug along the switching channel to a second position where it is in wetted contact with the second electrical contact and a third contact.

15. A method in accordance with claim 14, wherein energizing the first electromagnetic actuator comprises passing an electrical current through a first coil encircling the switching channel and energizing the second electromagnetic actuator comprises passing an electrical current through a second coil encircling the switching channel.

16. A method in accordance with claim 14, further comprising:

if the electrical circuit is to be completed;

de-energizing the first electromagnetic actuator after the solid slug has been moved to the first position; and

if the electrical circuit is to be broken;

de-energizing the second electromagnetic actuator after the solid slug has been moved to the second position.

17. A method for switching between a first electrical circuit, between a first electrical contact and a second electrical contact, and a second electrical circuit, between the second electrical contact and a third electrical contact, in a electromagnetic relay having solid slug wetted by a conducting liquid, the method comprising:

if the first electrical circuit is to be completed;

energizing a first electromagnetic actuator to move the solid slug along a switching channel to a first position where it is in wetted contact with the first electrical contact and the second electrical contact; and

if the second electrical circuit is to be completed;

energizing a second electromagnetic actuator to move the solid slug along the switching channel to a second position where it is in wetted contact with the second electrical contact and the third electrical contact.

18. A method in accordance with claim 17, wherein energizing the first electromagnetic actuator comprises passing an electrical current through a first coil encircling the switching channel and energizing the second electromagnetic actuator comprises passing an electrical current through a second coil encircling the switching channel.

19. A method in accordance with claim 17, further comprising:

if the first electrical circuit is to be completed;

de-energizing the first electromagnetic actuator after the solid slug has been moved to the first position; and

if the second electrical circuit is to be completed;

de-energizing the second electromagnetic actuator after the solid slug has been moved to the second position.