Electromagnetic switch

Information

  • Patent Grant
  • 6707357
  • Patent Number
    6,707,357
  • Date Filed
    Friday, August 30, 2002
    22 years ago
  • Date Issued
    Tuesday, March 16, 2004
    20 years ago
Abstract
An electromagnetic switch includes an electromagnetic module and a contact module that is to be plugged into the electromagnetic module. The contact module includes a fixed contact member and a movable contact member that is pivoted to the fixed contact member so as to be rotatable relative to the fixed contact member between a first angular position for establishing a first circuit, and a second angular position for establishing a second circuit.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




This invention relates to an electromagnetic switch, more particularly to an electromagnetic switch with an electromagnetic module and a contact module that is to be plugged into the electromagnetic module.




2. Description of the Related Art





FIGS. 1 and 2

illustrate a conventional electromagnetic switch that includes a housing


3


, first and second electromagnetic members


5


,


6


mounted in the housing


3


, a fixed contact member mounted in the housing


3


above the first and second electromagnetic members


5


,


6


, and a movable contact member


8


mounted in the housing


3


above the fixed contact member. Each of the first and second electromagnetic members


5


,


6


includes a coil


51


, a yoke


41


disposed below the coil


51


, and an armature


61


disposed above the coil


51


. The armature


61


of each of the first and second electromagnetic members


5


,


6


has a pair of pushing arms


71


extending upwardly therefrom toward and pivoted to the movable contact member


8


via pivot studs


83


which are formed on two opposite ends of the movable contact member


8


. First and second urging members


84


,


85


are mounted in the housing


3


for respectively urging the opposite ends of the movable contact member


8


in an upward direction. The movable contact member


8


includes first and second movable contacts


821


,


822


, and is rotatable between a first angular position, in which, the first movable contact


821


is turned downwardly to electrically contact a first fixed contact


311


of the fixed contact member, which results from downward movement of the armature


61


of the first electromagnetic member


5


against an urging action of the first urging member


84


via the yoke


41


of the first electromagnetic member.


5


upon actuation of the coil


51


of the first electromagnetic member


5


, and a second angular position, in which, the second movable contact


822


is turned downwardly to electrically contact a second fixed contact


312


of the fixed contact member, which results from downward movement of the armature


61


of the second electromagnetic member


6


against an urging action of the second urging member


85


via the yoke


41


of the second electromagnetic member


6


upon actuation of the coil


51


of the second electromagnetic member


6


.




The conventional electromagnetic switch is disadvantageous in that since all of the components thereof are mounted in the housing


3


, the assembly operation is relatively inconvenient and time-consuming. As a consequence, the manufacturing cost of the conventional electromagnetic switch is significantly increased. Moreover, the repair and the mounting and dismounting of a plurality of conductive wires thereon are laborious, and the urging members


84


,


85


tend to fail after a period of use.




SUMMARY OF THE INVENTION




Therefore, the object of the present invention is to provide an electromagnetic switch that dispenses with the use of the aforesaid urging members and that is capable of overcoming the aforesaid drawbacks of the prior art.




According to the present invention, there is provided an electromagnetic switch that comprises: an electromagnetic module including first and second electromagnetic members, each of which includes a coil, a yoke disposed above the coil, and an armature disposed below the coil and movable upwardly when actuated by the yoke upon application of an electric current to the coil, the electromagnetic module further including first and second pushing units connected to and projecting upwardly and respectively from the armatures of the first and second electromagnetic members, and co-movable with the armatures, respectively; and a contact module including a fixed contact member disposed above the first and second electromagnetic members and including conductive first and second fixed contacts, and a movable contact member disposed between the electromagnetic module and the fixed contact member and including a movable seat with two opposite sides, and conductive first and second movable contacts which are respectively disposed at the opposite sides of the movable seat and which are vertically and respectively aligned with the first and second fixed contacts. The movable seat is pivoted to the fixed contact member so as to permit the movable contact member to be rotatable relative to the fixed contact member among a first angular position, in which the first movable contact is in electrical contact with the first fixed contact, whereas the second movable contact is spaced apart from the second fixed contact when the coil of the first electromagnetic member is actuated, a second angular position, in which the second movable contact is in electrical contact with the second fixed contact, whereas the first movable contact is spaced apart from the first fixed contact when the coil of the second electromagnetic member is actuated, and a normal angular position, in which the first and second movable contacts are spaced apart from the first and second fixed contacts, respectively, when the coils of the first and second electromagnetic members are disabled. The first and second pushing units respectively extend toward the opposite sides of the movable seat in such a manner that the first pushing unit is moved upwardly upon actuation of the armature of the first electromagnetic member so as to move the movable contact member to the first angular position, and that the second pushing unit is moved upwardly upon actuation of the armature of the second electromagnetic member so as to move the movable contact member to the second angular position.











BRIEF DESCRIPTION OF THE DRAWINGS




In the drawings which illustrate an embodiment of the invention,





FIG. 1

is an exploded perspective view of a conventional electromagnetic switch;





FIG. 2

is a schematic view to illustrate how the electromagnetic switch of

FIG. 1

works;





FIG. 3

is a partly exploded perspective view of a preferred embodiment of an electromagnetic switch according to this invention;





FIG. 4

is a partly exploded perspective view illustrating an electromagnetic module and a contact module of the electromagnetic switch of

FIG. 3

;





FIG. 5

is an exploded perspective view of the contact module shown in

FIG. 4

;





FIG. 6

is exploded perspective view of the electromagnetic module shown in

FIG. 4

;





FIG. 7

is a partly sectional view to illustrate a movable contact member of the contact module shown in

FIG. 4

when disposed at a normal angular position relative to a fixed contact member of the contact module;





FIG. 8

is a partly sectional view of the movable contact member of the contact module shown in

FIG. 4

when disposed at a first angular position relative to the fixed contact member of the contact module;





FIG. 9

is a partly sectional view of the movable contact member of the contact module shown in

FIG. 4

when is disposed at a second angular position relative to the fixed contact member of the contact module;





FIG. 10

is a fragmentary sectional view of the movable contact member of the contact module shown in

FIG. 4

, which is disposed at an upper position relative to the fixed contact member of the contact module; and





FIG. 11

is a fragmentary partly sectional view to illustrate how the contact module is secured to the electromagnetic module shown in FIG.


4


.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT





FIGS. 3

to


7


illustrate a preferred embodiment of an electromagnetic switch according to this invention. The electromagnetic switch includes an electromagnetic module


300


and a contact module


200


that is to be plugged into the electromagnetic module


300


.




The electromagnetic module


300


includes first and second electromagnetic members


22


,


23


(see FIG.


6


), each of which includes a coil


222


(


232


), a yoke


221


(


231


) disposed above the coil


222


(


232


), and an armature


223


(


233


) disposed below the coil


222


(


232


) and movable upwardly when actuated by the yoke


221


(


231


) upon application of an electric current to the coil


222


(


232


). The electromagnetic module


300


further includes first and second pushing units


224


,


234


connected to and projecting upwardly and respectively from the armatures


223


,


233


of the first and second electromagnetic members


22


,


23


, and co-movable with the armatures


223


,


233


, respectively.




The contact module


200


includes a fixed contact member


12


disposed above the first and second electromagnetic members


22


,


23


and including pairs of conductive first and second fixed contacts


120


,


121


(only one pair of the first and second fixed contacts


120


,


121


will be described in the following paragraphs), and a movable contact member


13


disposed between the electromagnetic module


300


and the fixed contact member


12


and including a movable seat


132


with two opposite sides, and pairs of conductive first and second movable contacts


130


,


131


(only one pair of the first and second movable contacts


130


,


131


will be described in the following paragraphs) which are respectively disposed at the opposite sides of the movable seat


132


and which are vertically and respectively aligned with the respective pair of the first and second fixed contacts


120


,


121


. The movable seat


132


is pivoted to the fixed contact member


12


so as to permit the movable contact member


13


to be rotatable relative to the fixed contact member


12


among a first angular position (see FIG.


8


), in which the first movable contact


130


is in electrical contact with the first fixed contact


120


, whereas the second movable contact


131


is spaced apart from the second fixed contact


121


when the coil


222


of the first electromagnetic member


22


is actuated, a second angular position (see FIG.


9


), in which the second movable contact


131


is in electrical contact with the second fixed contact


121


, whereas the first movable contact


130


is spaced apart from the first fixed contact


120


when the coil


232


of the second electromagnetic member


23


is actuated, and a normal angular position (see FIG.


7


), in which the first and second movable contacts


130


,


131


are spaced apart from the first and second fixed contacts


120


,


121


, respectively, when the coils


222


,


232


of the first and second electromagnetic members


22


,


23


are disabled.




The first and second pushing units


224


,


234


respectively extend toward the opposite sides of the movable seat


132


in such a manner that the first pushing unit


224


is moved upwardly upon actuation of the armature


223


of the first electromagnetic member


22


so as to move the movable contact member


13


to the first angular position, and that the second pushing unit


234


is moved upwardly upon actuation of the armature


233


of the second electromagnetic member


23


so as to move the movable contact member


13


to the second angular position.




The electromagnetic module


300


further includes a first housing half


21


formed with a pair of opposing latch-engaging bars


217


. The contact module


200


further includes a second housing half


11


which is formed with a pair of opposing latches


113


and which is detachably coupled to the first housing half


21


via engagement between each of the latches


113


and a respective one of the latch-engaging bars


217


. An abutting member


1132


is disposed between and abuts against each of the latches


113


and the respective one of the latch-engaging bars


217


so as to tightly secure the first housing half


21


to the second housing half


11


(see FIG.


11


). The first and second electromagnetic members


22


,


23


are mounted in the first housing half


21


. The fixed contact member


12


and the movable contact member


13


are mounted in the second housing half


11


.




Each of the first and second pushing units


224


,


234


includes an armature casing


2241


(


2341


) with two opposite ends, and a pair of pushing arms


2243


(


2343


) extending upwardly and respectively from the opposite ends of the armature casing


2241


(


2341


) for moving the movable contact member


13


to a respective one of the first and second angular positions. The first housing half


21


has a top open end


210


defining a top opening


212


. The electromagnetic module


300


further includes a guiding plate


215


mounted on the top open end


210


of the first housing half


21


and covering the top opening


212


, and formed with a plurality of first through-holes


2152


for extension of the pushing arms


2243


(


2343


) of the first and second pushing units


224


,


234


therethrough, respectively, so as to guide upward and downward movements of the first and second pushing units


224


,


234


. Each of the armatures


223


,


233


is secured in the respective one of the armature casings


2241


,


2341


via a latch plate


2245


extending through the armature


223


(


233


) and the respective armature casing


2241


(


2341


).




The coil


222


(


232


) of each of the first and second electromagnetic members


22


,


23


includes a top flange


2220


(


2320


) formed with a pair of conductive clamping members


2221


(


2321


). The guiding plate


215


is further formed with a plurality of second through-holes


2153


for extension of the clamping members


2221


,


2321


of the top flanges


2220


,


2320


of the coils


222


,


232


of the first and second electromagnetic members


22


,


23


therethrough, respectively. The fixed contact member


12


further includes a plurality of conductive terminal legs


1211


which are releasably and respectively gripped by the clamping members


2221


,


2321


so as to permit the contact module


200


to be plugged into the electromagnetic module


300


and so as to permit electrical connection between each of the coils


222


,


232


of the first and second electromagnetic members


22


,


23


and electrical wires (not shown) via a respective one of the terminal legs


1211


.




The fixed contact member


12


further includes a stationary seat


122


with two opposite sides. The first and second fixed contacts


120


,


121


are disposed at the opposite sides of the stationary seat


122


of the fixed contact member


12


, respectively. A pair of pivotal lugs


123


extend downwardly from two opposite ends of the stationary seat


122


of the fixed contact member


12


between the first and second fixed contacts


120


,


121


, and are formed with elongated slots


124


, respectively. The movable seat


132


of the movable contact member


13


further includes a pair of pivot studs


133


that respectively extend into and that are movable within the elongated slots


124


so as to permit pivotal action of the movable contact member


13


relative to the fixed contact member


12


between the first and second angular positions.




Referring to

FIG. 10

, in combination with FIGS.


5


and


7


, each of the first and second movable contacts


130


,


131


of the movable contact member


13


is spaced apart from a respective one of the first and second fixed contacts


120


,


121


by a vertical length (L) when the movable contact member


13


is disposed at the normal angular position. Each of the elongated slots


124


has a vertical height (H) that is less than the vertical length (L) so as to prevent simultaneous electrical contact between the first movable contact


130


and the first fixed contact


120


and between the second movable contact


131


and the second fixed contact


121


when the coils


222


,


232


of the first and second electromagnetic members


22


,


23


are simultaneously actuated. As shown in

FIG. 10

, the movable contact member


13


is moved upwardly to an upper position, in which, each of the pivot studs


133


abuts against a top end of a slot-confining wall of a respective one of the elongated slots


124


, when the coils


222


,


232


of the first and second electromagnetic members


22


,


23


are simultaneously actuated.




Referring to

FIGS. 3

,


6


and


8


, the second housing half


11


has a top wall


111


formed with a plurality of first and second openings


112


. The movable contact member


13


further includes a plurality of conductive bridges


135


(only one of the bridges


135


will be described in the following paragraphs), each of which is mounted on the movable seat


132


and interconnects two of the first and second movable contacts


130


,


131


, and a plurality of conductive third movable contacts


136


(only one of the third contacts


136


will be described in the following paragraphs), each of which is electrically connected to the respective bridge


135


at a position between the first and second movable contacts


130


,


131


in such a manner that the first and third movable contacts


130


,


136


form a first circuit when the movable contact member


13


is disposed at the first angular position, and that the second and third movable contacts


131


,


136


form a second circuit when the movable contact member


13


is disposed at the second angular position. The fixed contact member


12


further includes a plurality of conductive third fixed contacts


126


(only one of the third fixed contacts


126


will be described in the following paragraphs), each of which is in constant electrical contact with the respective third movable contact


136


via a conductive spring piece


127


so that the first circuit passes through the first fixed contact


120


, the first movable contact


130


, the third movable contact


136


, and the third fixed contact


126


, and that the second circuit passes through the second fixed contact


121


, the second movable contact


131


, the third movable contact


136


, and the third fixed contact


126


. Each of the first and third fixed contacts


120


,


126


has a blade portion


1201


(


1261


) projecting upwardly and outwardly of the second housing half


11


from the stationary seat


122


through a respective one of the first and second openings


112


.




Since the contact module


200


can be plugged into the electromagnetic module


300


, the aforesaid drawbacks as encountered in the prior art can be eliminated. Moreover, the electromagnetic switch of this invention dispenses with the use of the aforesaid urging members employed in the conventional electromagnetic switch.




With the invention thus explained, it is apparent that various modifications and variations can be made without departing from the spirit of the present invention. It is therefore intended that the invention be limited only as recited in the appended claims.



Claims
  • 1. An electromagnetic switch comprising:an electromagnetic module including first and second electromagnetic members, each of which includes a coil, a yoke disposed above said coil, and an armature disposed below said coil and movable upwardly when actuated by said yoke upon application of an electric current to said coil, said electromagnetic module further including first and second pushing units connected to and projecting upwardly and respectively from said armatures of said first and second electromagnetic members, and co-movable with said armatures, respectively; and a contact module including a fixed contact member disposed above said first and second electromagnetic members and including conductive first and second fixed contacts, and a movable contact member disposed between said electromagnetic module and said fixed contact member and including a movable seat with two opposite sides, and conductive first and second movable contacts which are respectively disposed at said opposite sides of said movable seat and which are vertically and respectively aligned with said first and second fixed contacts, said movable seat being pivoted to said fixed contact member so as to permit said movable contact member to be rotatable relative to said fixed contact member among a first angular position, in which said first movable contact is in electrical contact with said first fixed contact, whereas said second movable contact is spaced apart from said second fixed contact when said coil of said first electromagnetic member is actuated, a second angular position, in which said second movable contact is in electrical contact with said second fixed contact, whereas said first movable contact is spaced apart from said first fixed contact when said coil of said second electromagnetic member is actuated, and a normal angular position, in which said first and second movable contacts are spaced apart from said first and second fixed contacts, respectively, when said coils of said first and second electromagnetic members are disabled; wherein said first and second pushing units respectively extend toward said opposite sides of said movable seat in such a manner that said first pushing unit is moved upwardly upon actuation of said armature of said first electromagnetic member so as to move said movable contact member to said first angular position, and that said second pushing unit is moved upwardly upon actuation of said armature of said second electromagnetic member so as to move said movable contact member to said second angular position.
  • 2. The electromagnetic switch of claim 1, wherein said electromagnetic module further includes a first housing half, said contact module further including a second housing half which is detachably coupled to said first housing half, said first and second electromagnetic members being mounted in said first housing half, said fixed contact member and said movable contact member being mounted in said second housing half.
  • 3. The electromagnetic switch of claim 2, wherein each of said first and second pushing units includes an armature casing with two opposite ends, and a pair of opposing pushing arms extending upwardly and respectively from said opposite ends of said armature casing for moving said movable contact member to a respective one of said first and second angular positions, said first housing half having a top open end defining a top opening, said electromagnetic module further including a guiding plate mounted on said top open end of said first housing half and covering said top opening, and formed with a plurality of first through-holes for extension of said pushing arms of said first and second pushing units therethrough, respectively, so as to guide upward and downward movements of said first and second pushing units.
  • 4. The electromagnetic switch of claim 3, wherein said coil of each of said first and second electromagnetic members includes a top flange formed with a pair of conductive clamping members, said guiding plate being further formed with a plurality of second through-holes for extension of said clamping members of said top flanges of said coils of said first and second electromagnetic members therethrough, respectively, said fixed contact member further including a plurality of conductive terminal legs which are releasably and respectively gripped by said clamping members so as to permit said contact module to be plugged into said electromagnetic module.
  • 5. The electromagnetic switch of claim 1, wherein said fixed contact member further includes a stationary seat with two opposite sides, said first and second fixed contacts being disposed at said opposite sides of said stationary seat of said fixed contact member, respectively, said fixed contact member further including a pair of pivotal lugs that extend downwardly from said stationary seat of said fixed contact member between said first and second fixed contacts and that are formed with elongated slots, respectively, said movable seat of said movable contact member further including a pair of pivot studs that respectively extend into and that are movable within said elongated slots so as to permit pivotal action of said movable contact member relative to said fixed contact member between said first and second angular positions.
  • 6. The electromagnetic switch of claim 5, wherein each of said first and second movable contacts of said movable contact member is spaced apart from a respective one of said first and second fixed contacts by a vertical length when said movable contact member is disposed at said normal angular position, each of said elongated slots having a vertical height that is less than said vertical length so as to prevent simultaneous electrical contact between said first movable contact and said first fixed contact and between said second movable contact and said second fixed contact when said coils of said first and second electromagnetic members are simultaneously actuated.
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