Protection device

• US 10,283,295 B2
• Filed: 04/17/2014
• Issued: 05/07/2019
• Est. Priority Date: 04/19/2013
• Status: Active Grant

• Current Assignee: Littelfuse Japan G.K. (Littelfuse Incorporated)
• Original Assignee: Littelfuse Japan G.K. (Littelfuse Incorporated)
• Inventors: Mochizuki, Hirofumi, Tanaka, Arata
• Primary Examiner(s): Crum, Jacob R
• Application Number:
  US14/785,316
• Publication Number:
  US 20160086753A1
• Time in Patent Office: 1,846 Days
• Field of Search: 337377
• CPC Class Codes: H01H 2037/5463 the bimetallic snap element forming part of switched circuit
• CPC Class Codes: H01H 2037/5481 the bimetallic snap element being mounted on the contact spring
• CPC Class Codes: H01H 37/34 Means for transmitting heat thereto, e.g. capsule remote from contact member
• CPC Class Codes: H01H 37/46 actuated due to expansion or contraction of a solid deflection of a bimetallic element H01H37/52
• CPC Class Codes: H01H 37/52 actuated due to deflection of bimetallic element
• CPC Class Codes: H01H 37/5427 encapsulated in sealed miniaturised housing

Abstract

The present invention provides a protection device including a bimetal component and a PTC component. This protection device includes a resin base, a first terminal, a second terminal, a PTC component, a bimetal component, an arm, an upper plate and a resin cover. A portion of the first terminal configures a first electrode, and a portion of a second terminal configures the second electrode, and the first electrode and the second electrode are exposed outward at the bottom surface of the resin base. In a normal state, the first terminal, the arm and the second terminal are electrically connected in series. When the bimetal component is activated, the first terminal and the arm become electrically cut off while the first terminal, the PTC component, the bimetal component, the arm and the second terminal are electrically connected in series in the mentioned order.

Claims

1. A protection device comprising a resin base, a first terminal, a second terminal, a PTC component, a bimetal component, an arm, an upper plate and a resin cover wherein

a portion of the first terminal configures a first electrode, and a portion of the second terminal configures a second electrode,

the first electrode and the second electrode extend around to form at least a portion of a side surface and a flat bottom surface such that the first and second electrodes are exposed outward and lie in the same plane as a flat bottom surface of the resin base, the first terminal having a rib at an end opposite of the side surface and the flat bottom surface of the first electrode and extending into a space of the resin base to contact the PTC component,

in a normal state, the first terminal, the arm and the second terminal are electrically connected in series, and

when the bimetal component is activated, the first terminal and the arm becomes electrically cut off while the first terminal, the PTC component, the bimetal component, the arm and the second terminal are electrically connected in series in thus mentioned order.

2. The protection device according to claim 1, wherein the bimetal component has been subjected to a heat-treatment.

3. The protection device according to claim 2, wherein a temperature of the heat-treatment is higher than a temperature of a soldering for surface-mounting the protection device.

4. The protection device according to claim 1, wherein the first terminal has a contact part formed by swaging a contact material through a hole of the first terminal, the contact material having a larger thermal capacity than the first terminal.

5. The protection device according to claim 4, wherein the contact material is a silver-nickel alloy.

6. The protection device according to claim 1, wherein the resin base is formed from a thermal resistant resin.

7. The protection device according to claim 1, wherein the upper plate has an engaging part having a hook-like shape and is fixed on the resin base by engaging the engaging part to an engaged part having a notch shape of the resin base.

8. The protection device according to claim 1, wherein the arm has a crank shape portion in the space of the resin base.

9. The protection device according to claim 1, wherein the exposed portions of the first terminal and/or the second terminal are plated with a metal unsusceptible to oxidation.

10. The protection device according to claim 9, wherein the metal unsusceptible to oxidation is gold.

11. The protection device according to claim 1, wherein the first electrode and the second electrode are provided so as to be line-symmetric with respect to a center line between the first electrode and the second electrode at the bottom surface of the resin base.

12. A protection device comprising:

a resin base having a flat bottom surface and surrounding side surfaces;

a first terminal extending around to form at least a portion of a side surface and a flat bottom surface, the first terminal including a first electrode, wherein the first electrode is exposed outward and lies in the same plane as the flat bottom surface of the resin base;

a second terminal extending around to form at least a portion of a side surface and a flat bottom surface opposite the first terminal, the second terminal including a second electrode, wherein the second electrode is exposed outward and lies in the same plane as the flat bottom surface of the resin base and the first electrode;

a PTC component disposed in a space formed of the resin base, the first terminal, and the second terminal, wherein the first terminal includes a rib at an end opposite of the side surface and the flat bottom surface of the first electrode to extend into a space of the resin base to contact the PTC component,

a bimetal component disposed over the PTC component; and

an arm extending over the bimetal component and having an end connected to the second terminal and removably attachable to the first terminal;

wherein in a normal state, the first terminal, the arm, and the second terminal are electrically connected in series; and

wherein when the bimetal component is activated, the first terminal and the arm becomes electrically cut off while the first terminal, the PTC component, the bimetal component, the arm and the second terminal are electrically connected in series order.