EP1906429A2

EP1906429A2 - Safety double-break switch

Info

Publication number: EP1906429A2
Application number: EP07005284A
Authority: EP
Inventors: Tsang-I Chen
Original assignee: SWAIN INDUSTRY Co Ltd
Current assignee: SWAIN INDUSTRY Co Ltd
Priority date: 2006-09-26
Filing date: 2007-03-14
Publication date: 2008-04-02
Also published as: CN200953333Y; EP1906429A3

Abstract

A safety double-break switch (100) is disclosed to include a housing (10), which has a button (14) pivoted to the main body (11) thereof, and a first circuit breaking mechanism (20) and a second circuit breaking mechanism (30) respectively mounted in first and second accommodation chambers (112, 113) in the housing (10) and respectively connected to external power source. When biasing the button (14) to ON position, the first circuit breaking mechanism (20) and the second circuit breaking mechanism (30) are electrically connected with the power source, thereby resulting in the current flow. When biasing the button (14) to OFF position, the first circuit breaking mechanism (20) interrupts the power source to form a first broken circuit, and the second circuit breaking mechanism (30) interrupts the power source to form a second broken circuit.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to power switches and more particularly, to a safety double-break switch.

2. Description of the Related Art

A regular safety switch, as shown in FIG 1, comprises a housing 1, which houses two power terminals 2a and 2b, a conductive piece 3, a switching mechanism 4, and a spring member 5. The conductive piece 3 has one end fixedly connected to one power terminal 2a. The switching mechanism 4 comprises a button 4a and an actuating rod 4b coupled to the bottom side of the button 4a. The button 4a is mounted on the top side of the housing 1. The other end of the actuating rod 4b is coupled to the other end of the conductive piece 3. The spring member 5 is connected to one end of the actuating rod 4b to which the conductive piece 3 is connected. When the user pressing the button 4a, the two ends of the conductive piece 3 are respectively forced into contact with the two power terminals 2a and 2b, thereby resulting in the current flow. When the conductive piece 3 is overloaded (i.e., upon an overcurrent), the conductive piece 3 is caused to deform by heat. As a result, the spring member 5 is forced to jump upwards, so as to push the actuating rod 4b to displace upwards. The conductive piece 3 and the spring member 5 are actuated to move upwards to bring about the separation of the conductive piece 3 from the power source terminal 2b, thereby resulting in interruption of the flow of the electric current. In light of the spring member 5 urging only one side of the actuating rod 4b, the actuating rod 4b is apt to move aside.
In view of the drawbacks of the aforesaid safety switch, the inventor of the present invention created an improved structure of safety switch, as indicated in US 6,525,639 , entitled "Power source electrical switch", in which two spring members are used to simultaneously urge the two sides of the actuating rod, thereby assuring accurate action of the actuating rod.
With respect to electrical wiring, there are three lines, namely, the hard line, the neutral line, and the ground line. In the aforesaid two safety switches, either single side urging type (single spring member) or double-side urging type (two spring members), the switching mechanism is to connect or interrupt the hard line. This single line interruption measure still cannot eliminate flowing of electric current through another line (for example, neutral line) in certain cases (for example, aging, fatigue, or failure of one component part), and may result in fire accident.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention has been accomplished under the circumstances in view. It is therefore one objective of the present invention to provide a safety double-break switch, which has two breakpoints built in the current loop, assuring accurate power interruption action.
To achieve this objective of the present invention, the safety double-break switch comprises a housing, a first circuit breaking mechanism, and a second circuit breaking mechanism. The housing comprises a main body, and a button pivotally mounted on the main body. The main body has a first accommodation chamber and a second accommodation chamber. The first circuit breaking mechanism is mounted inside the first accommodation chamber of the housing, comprising a plurality of first power terminals, a first conductive piece, a first link, and at least one first spring member. The first conductive piece has a first end fixedly connected to one of the first power terminals, and a second end electrically connectable to and disconnectable from another first power terminal. The first link has a first end connected to the button and a second end connected to the first conductive piece and is movable by the button to force the first conductive piece into contact or away from the associating first power terminal. The at least one first spring member each has two distal ends respectively affixed to a part of the housing inside the first accommodation chamber and the first link to impart an elastic force to the first link for enabling movement of the first conductive piece away from the associating first power terminal when the first conductive piece receives a heat energy over a predetermined level. The second circuit breaking mechanism is mounted inside the second accommodation chamber of the housing, comprising a plurality of second power terminals, a second conductive piece, a second link, and at least one second spring member. The second conductive piece has a first end fixedly connected to one of the second power terminals and a second end electrically connectable to and disconnectable from another second power terminal. The second link has a first end connected to the button and a second end connected to the second conductive piece, and is movable by the button to force the second conductive piece into contact or away from the associating second power terminal. The at least one second spring member each has two distal ends respectively affixed to a part of the housing inside the second accommodation chamber and the second link to impart an elastic force to the second link for enabling movement of the second conductive piece away from the associating second power terminal when the second conductive piece receives a heat energy over a predetermined level.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG 1 is a sectional view of a safety switch according to the prior art;
FIG 2 is an exploded view of a safety double-break switch according to a preferred embodiment of the present invention;
FIG 3 is a side plan view of the present invention, showing OFF status of the safety double-break switch;
FIG 4 corresponds to FIG 3 when viewed from the other side;
FIG 5 is a sectional assembly view of the present invention, showing OFF status of the safety double-break switch;
FIG 6 is a side plan view of the present invention, showing ON status of the safety double-break switch;
FIG 7 corresponds to FIG 6 when viewed from the other side;
FIG 8 is a sectional assembly view of the present invention, showing ON status of the safety double-break switch;
FIG 9 is a side plan view of the present invention, showing OFF status of the safety double-break switch and the action of the fist adjustment device;
FIG 10 is a side plan view of the present invention, showing OFF status of the safety double-break switch and the action of the second adjustment device;
FIG 11 is a side plan view of the present invention, showing ON status of the safety double-break switch and the action of the first adjustment device, and
FIG 12 is a side plan view of the present invention, showing ON status of the safety double-break switch and the action of the second adjustment device.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 2-12, a safety double-break switch 100 in accordance with the preferred embodiment of the present invention comprises a housing 10, a first circuit breaking mechanism 20, and a second circuit breaking mechanism 30.
The housing 10 is made of an electrically insulative and fire resisting material, having a main body 11, two covers 12 and 13, and a button 14. The main body 11 has a top opening 111, a first accommodation chamber 112 at one side, and a second accommodation chamber 113 at an opposite side. The first accommodation chamber 112 and the second accommodation chamber 113 are in communication with the top opening 111. The first accommodation chamber 112 and the second accommodation chamber 113 have made therein predetermined shapes of posts and grooves so that the first accommodation chamber 112 can accommodate the first circuit breaking mechanism 20 and the second accommodation chamber 113 can accommodate the second circuit breaking mechanism 30. The two covers 12 and 13 are respectively fastened to two opposite sides of the housing 11 to close the first accommodation chamber 112 and the second accommodation chamber 113. The button 14 is made of an electrically insulative and fire resisting material, and pivotally mounted in the top opening 111 of the housing 11 and movable between an ON position and an OFF position.
The first circuit breaking mechanism 20 comprises three first power terminals 21, 22 and 23, a first conductive piece 24, a first link 25, two first holders 26, two first spring members 27, and a first adjustment device 28.
The three first power terminals 21, 22 and 23 are made of metal or an electrically conducting material for connection to an external power source (for example, the hard line in electrical wiring). These three first power terminals 21, 22 and 23 are separated from one another and respectively fixedly mounted inside the first accommodation chamber 112 of the housing 10.
The first conductive piece 24 is made of metal, alloy, superalloy, or any of a variety of electrically conductive thermal couple materials. The first conductive piece 24 can sustain a predetermined amount of thermal energy under a stable status. Further, the first conductive piece 24 is mounted inside the first accommodation chamber 112 of the housing 10, having one end fixedly connected to one first power terminal 21 and the other end providing a notch 241.
The first link 25 is mounted inside the first accommodation chamber 112 of the housing 10, having one end fixedly connected to the bottom wall of the button 14 near one side and the other end providing a retaining notch 251. The retaining notch 251 of the first link 25 is engaged with the notch 241 of the first conductive piece 24 so that the button 14 and the first conductive piece 24 are movable together by means of the connection of the first link 25, and therefore the first conductive piece 24 is urged into contact with or disconnected from one first power terminal 22 when the first link 25 is moved.
The two first holders 26 are fixedly mounted in the first accommodation chamber 112 inside the housing 10 at two sides relative to the first link 25, each defining a retaining groove 261 facing the first link 25.
The two first spring members 27 are made of a thermal conductive material, each, having one end respectively engaged in the retaining grooves 261 of the first holders 26 and the other end respectively connected to the first link 25. By means of the elastic force of the first spring members 27, the first spring members 27 impart a pressure to two opposite sides of the first link 25. Because the first spring members 27 urge the two sides of the first link 25, the action of the first link 25 is accurate.
The first adjustment device 28 is used to adjust the thermal energy sustaining level of the first conductive piece 24. The first adjustment device 28 comprises a first locating member 281 and a first urging member 282. The first locating member 281 is fixedly mounted inside the first accommodation chamber 112 of the housing 10. The first urging member 282 is pressable on the first conductive piece 24, and adjustable to change the prestress set by the urging member 282 to the first conductive piece 24. According to the present preferred embodiment, the first locating member 281 has a screw hole 283. The first urging member 282 is a screw threaded into the screw hole 283 and rotatable inwards/outwards to change the contact prestress to the first conductive piece 24.
The second breaking mechanism 30 comprises three second power terminals 31, 32 and 33, a second conductive piece 34, a second link 35, two second holders 36, two second spring members 37, and a second adjustment device 38.
The three second power terminals 31, 32 and 33 are made of metal or an electrically conducting material for connection to an external power source (for example, the neutral line in electrical wiring). These three second power terminals 31, 32 and 33 are separated from one another and respectively fixedly mounted inside the second accommodation chamber 113 of the housing 10.
The second conductive piece 34 is made of metal, alloy, superalloy, or any of a variety of electrically conductive thermal couple materials. The second conductive piece 34 can sustain a predetermined amount of thermal energy under a stable status. Further, the second conductive piece 34 is mounted inside the second accommodation chamber 113 of the housing 10, having one end fixedly connected to one second power terminal 31 and the other end providing a notch 341.
The second link 35 is mounted inside the second accommodation chamber 113 of the housing 10, having one end fixedly connected to the bottom wall of the button 14 near one side and the other end providing a retaining notch 351. The retaining notch 351 of the second link 35 is engaged with the notch 341 of the second conductive piece 34 so that the button 14 and the second conductive piece 34 are movable together by means of the connection of the second link 35, and therefore the second conductive piece 34 is urged into contact with or disconnected from the second power terminal 32 when the second link 35 is moved.
The two second holders 36 are fixedly mounted in the second accommodation chamber 113 inside the housing 10 at two sides relative to the second link 35, each defining a retaining groove 361 facing the second link 35.
The two second spring members 37 are made of a thermal conductive material, each having one end respectively engaged in the retaining grooves 361 of the second holders 36 and the other end respectively connected to the second link 35. By means of the elastic force of the second spring members 37, the second spring members 37 impart a pressure to two opposite sides of the second link 35. Because the second spring members 37 urge the two sides of the second link 35, the action of the second link 35 is accurate.
The second adjustment device 38 is used to adjust the thermal energy sustaining level of the second conductive piece 34. The second adjustment device 38 comprises a second locating member 381 and a second urging member 382. The second locating member 381 is fixedly mounted inside the second accommodation chamber 113 of the housing 10. The second urging member 382 is pressable on the second conductive piece 34, and adjustable to change the prestress set by the urging member 382 to the second conductive piece 34. According to the present preferred embodiment, the second locating member 381 has a screw hole 383. The second urging member 382 is a screw threaded into the screw hole 383 and rotatable inwards/outwards to change the contact prestress to the second conductive piece 34.
After understanding of the structural details of the component parts of the safety double-break switch, the operation of the safety double-break switch and its advantages are described hereinafter.
When the button 14 is moved by an external force (the user) to the ON position, the first link 25 and the second link 35 are lowered to urge the first conductive piece 24 and the second conductive piece 34 into contact with the corresponding first power terminal 22 (see FIG 6) and the corresponding second power terminal 32 (see FIG 7), thereby resulting in the current flow (see FIG 8). In case the electric current that goes through the first conductive piece 24 or the second conductive piece 34 is excessively high, i.e., over the thermal energy sustaining power of the first conductive piece 24 or the second conductive piece 34, the first conductive piece 24 or the second conductive piece 34 is caused to deform, thereby causing every first spring member 27 and every second spring member 37 to jump and to further push the first link 25 and the second link 35 upwards, and therefore the first link 25 and the second link 35 move the button 14 to the OFF position to disconnect the first conductive piece 24 from the corresponding first power terminal 22 (see FIG 3) and the second conductive piece 34 from the corresponding second power terminal 32 (see FIG 4). Separation of the first conductive piece 24 from the corresponding first power terminal 22 forms a first broken circuit. Separation of the second conductive piece 34 from the corresponding second power terminal 32 forms a second broken circuit. Therefore, by means of separation of the first conductive piece 24 from the corresponding first power terminal 22 and separation of the second conductive piece 34 from the corresponding second power terminal 32 (see FIG 5) to form two broken circuits (i.e., broken hard line and broken neutral line), the safety of the present invention is enhanced, and the accurate action of the off action of the invention is assured.
Further, by means of adjusting the urging members 282 and 382 of the first and second adjustment devices 28 and 38 to change the prestress applied to the first and second conductive pieces 24 and 34, the heat receiving capacity of the first and second conductive pieces 24 and 34 in which the first and second conductive pieces 24 and 34 are caused to deform and to break the circuit is relatively changed, i.e., the higher the pressure applied by the urging members 282 and 382 to the first and second conductive pieces 24 and 3 is, the lower the heat receiving capacity of the first and second conductive pieces 24 and 34 to return to off-circuit status will be. On the contrary, when the pressure applied by the urging members 282 and 382 to the first and second conductive pieces 24 and 3 is relatively small, the heat receiving capacity of the first and second conductive pieces 24 and 34 to return to off-circuit status will be relatively increased. As shown in FIGS. 9 and 10, when the he urging members 282 and 382 are pressed on the first and second conductive pieces 24 and 34 to impart a prestress to the first and second conductive pieces 24 and 34 and to change the heat receiving capacity of the first and second conductive pieces 24 and 34 in which the first and second conductive pieces 24 and 34 are caused to deform and to break the circuit. Therefore, when the button 14 is on the ON position, the first conductive piece 24 is urged by the first urging member 282 (see FIG 11), and the heat receiving capacity of the first conductive piece 24 in which the first conductive piece 24 is caused to deform and to break the circuit is reduced, thereby setting the condition for allowing a relatively smaller amount of electric current to pass through the first conductive piece 24. Similarly, the second conductive piece 34 is urged by the second urging member 382 (see FIG 12), and the heat receiving capacity of the second conductive piece 34 in which the second conductive piece 34 is caused to deform and to break the circuit is reduced, thereby setting the condition for allowing a relatively smaller amount of electric current to pass through the second conductive piece 34.
Therefore, by means of the first circuit breaking mechanism and the second circuit breaking mechanism to constitute double-break switching loop, the invention eliminates the chance of flowing of electric current through another line result when one line is off, enhancing the safety and preventing occurrence of a fire accident. Further, the first spring members and the second spring members respectively urge the two sides of the first link and the second link, assuring accurate action when switching off the switch. Further, by means of the first adjustment device and the second adjustment device to adjust the heat receiving capacity of the first conductive piece and the second conductive piece in which the first conductive piece and the second conductive piece are caused to deform and to break the circuit, the amount of electric current that is allowed to pass is relatively changed, enhancing the safety of the present invention.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

A safety double-break switch (100), characterized in that the safety double-break switch (100) comprises:
a housing (10) having a main body (11) and a button (14) pivotally mounted on said main body (11), said main body (11) having a first accommodation chamber (112) and a second accommodation chamber (113);

a first circuit breaking mechanism (20) mounted inside said first accommodation chamber (112) of said housing (10) and provided with a plurality of first power terminals (21, 22), a first conductive piece (24), a first link (25), and at least one first spring member (27), said first conductive piece (24) having a first end fixedly connected to one of said first power terminals (21) and a second end electrically connectable to and disconnectable from another one of said first power terminals (22), said first link (25) having a first end connected to said button (14) and a second end connected to said first conductive piece (24) and being movable by said button (14) to force said first conductive piece (24) into contact or away from the associating first power terminal (22), said at least one first spring member (27) each having two distal ends respectively affixed to a part of said housing (10) inside said first accommodation chamber (112) and said first link (25) to impart an elastic force to said first link (25) for enabling movement of said first conductive piece (24) away from the associating first power terminal (22) when said first conductive piece (24) receives a heat energy over a predetermined level; and

a second circuit breaking mechanism (30) mounted inside said second accommodation chamber (113) of said housing (10) and provided with a plurality of second power terminals (31, 32), a second conductive piece (34), a second link (35), and at least one second spring member (37), said second conductive piece (35) having a first end fixedly connected to one of said second power terminals (31) and a second end electrically connectable to and disconnectable from another one of said second power terminals (32), said second link (35) having a first end connected to said button (14) and a second end connected to said second conductive piece (34) and being movable by said button (14) to force said second conductive piece into contact or away from the associating second power terminal (32), said at least one second spring member (37) each having two distal ends respectively affixed to a part of said housing (10) inside said second accommodation chamber (113) and said second link (35) to impart an elastic force to said second link (35) for enabling movement of said second conductive piece (34) away from the associating second power terminal (32) when said second conductive piece (34) receives a heat energy over a predetermined level.
The safety double-break switch (100) as claimed in claim 1, characterized in that said first conductive piece (24) and said second conductive piece (34) are made of a thermo couple material.
The safety double-break switch (100) as claimed in claim 1, characterized in that said first circuit breaking mechanism (20) comprises at least one first holder (26) fixedly mounted in said first accommodation chamber (112) of said housing (10), said at least one first holder (26) each defining a retaining groove (261) for the positioning of one end of said first spring member (27); said second circuit breaking mechanism (30) comprises at least one second holder (36) fixedly mounted in said second accommodation chamber (113) of said housing (10), said at least one second holder (36) each defining a retaining groove (361) for the positioning of one end of said second spring member (37).
The safety double-break switch (100) as claimed in claim 1, characterized in that said first circuit breaking mechanism (20) further comprises a first adjustment device (28) adapted to adjust the heat receiving capacity of said first conductive piece (24).
The safety double-break switch (100) as claimed in claim 4, characterized in that said first adjustment device (28) comprises a first locating member (281) fixedly mounted inside said first accommodation chamber (112) of said housing (10), and a first urging member (282) coupled to said first locating member (281) to impart a prestress to said first conductive piece (24) and movable relative to said first locating member (281) to adjust the prestress being applied to said first conductive piece (24) and to further change the heat receiving capacity of said first conductive piece (24).
The safety double-break switch (100) as claimed in claim 5, characterized in that said first locating member (281) has a screw hole (283), and said first urging member (282) is a screw threaded into the screw hole (283) of said first locating member (281).
The safety double-break switch (100) as claimed in claim 1, characterized in that said second circuit breaking mechanism (30) further comprises a second adjustment device (38) adapted to adjust the heat receiving capacity of said second conductive piece (34).
The safety double-break switch (100) as claimed in claim 7, characterized in that said second adjustment device (38) comprises a second locating member (381) fixedly mounted inside said second accommodation chamber (113) of said housing (10), and a second urging member (382) coupled to said second locating member (381) to impart a prestress to said second conductive piece (34) and movable relative to said second locating member (381) to adjust the prestress being applied to said second conductive piece (34) and to further change the heat receiving capacity of said second conductive piece (34).
The safety double-break switch (100) as claimed in claim 8, characterized in that said second locating member (381) has a screw hole (383), and said second urging member (382) is a screw threaded into the screw hole (383) of said second locating member (381).