Polarized electromagnetic relay

A polarized electromagnetic relay has a base body, an armature, an envelope that comprises insulating material, a coil, a core and a bar-shaped magnet. The base plane is defined by a bottom side of the base body. The armature is arranged between two contact springs that lie parallel to each other in a common plane. Two transverse terminal webs, which have their sheet metal plane extending perpendicular to the base plane, extend out of the envelope in the area of the rotational axis of the armature. The terminal webs are respectively connected with fastening tabs that have a sheet metal plane extending perpendicular to the base plane. The contact springs exhibit two spring arms and a connecting web, respectively, which has its sheet metal plane extending perpendicular to the base plane. The spring arms exhibit a contact making part and a part that is embedded in the envelope, respectively. The part that is embedded in the envelope merges into the connecting web.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention is directed to a polarized electromagnetic relay with 
a base body comprising an insulating material, which defines a base plane 
with its bottom side, and in which terminal tracks for stationary contact 
elements as well as terminal elements for stationary and movable contact 
elements are embedded, a pivotable armature that is arranged above the 
base body, whose rotational axis runs parallel to the base plane and which 
is arranged between at least two contact springs of a contact spring group 
that is connected to the armature, which springs are arranged in a common 
plane and run parallel to each other so that the contact springs cooperate 
with the stationary terminal elements at the base body in response to the 
movement of the armature, an envelope that comprises insulating material 
which surrounds the contact springs in a central sector and from which two 
transverse terminal webs that are connected with the contact springs 
project in the area of the rotational axis of the armature, whereby the 
terminal webs are respectively connected with a fastening tab, which has 
its sheet metal plane extending perpendicular to the base plane, a coil, 
whose axis runs parallel to the base plane and perpendicular to the 
armature and whose winding terminal elements pass perpendicularly through 
the base plane, a core that is arranged axially in the coil and to whose 
end pole shoes that are directed toward the armature connect and which 
form at least one working air gap with the armature and at least one 
bar-shaped permanent magnet, which is arranged parallel to the coil axis 
between the pole shoes and which generates a like polarization at the ends 
of the pole shoes. 
2. Prior Art 
A polarized relay is disclosed in U.S. Pat. No. 4,695,813, whose disclosure 
is incorporated herein by reference thereto and which claims priority from 
the same Japanese Application as European 0 197 391 B2. In this U.S. 
Patent, a polarized relay is disclosed, whose armature is carried by a 
pair of contact springs. Together with the armature, the contact springs 
are movable and are provided with a lever arm in their center areas that 
respectively extends transverse and is connected tightly to a terminal 
element at a base body. Thus, the lever arms are applied of one-piece to 
the contact springs and represent elastic torsion elements with a limited 
deformability. Given the relays of the U.S. Patent, the terminal tabs of 
the torsion spring webs are bent down and are connected to center contact 
terminal pieces in a recess in the base body. Thus, accessibility to the 
fastening points of the terminal tabs of the torsion spring web at the 
center contact terminal piece is difficult, whereby a simple and precise 
adjustment is impeded. 
SUMMARY OF THE INVENTION 
The present invention is directed to the object of creating a polarized 
relay with a reduced overall height, wherein a precise and permanent 
adjusting of contact clearances and excess stroke is possible and which is 
characterized by a high shock resistance. 
According to the invention, this is achieved wherein the coil is arranged 
above the armature, the terminal webs have their sheet metal plane 
extending perpendicular to the base plane, the contact springs comprise 
two spring arms and a connecting web, respectively, and the connecting web 
has its sheet metal plane extending perpendicular toward the base plane. 
The spring arms comprise a contact making part and a part embedded in the 
envelope, respectively, whereby the part that is embedded in the envelope 
merges into a connecting web and the fastening tabs are respectively 
fastened to a center contact terminal pin that extends perpendicularly out 
of the base body. 
As a result of the inventive solution, it is possible to reduce the overall 
height of the polarized electromagnetic relay from approximately 10 mm to 
5 mm. According to a preferred embodiment, the fastening tab is an 
extension of a terminal web that is bent in the direction of the coil. 
Preferably, the terminal web is connected via a leaf spring web to a 
spring arm of the contact spring. Thus, the terminal web represents an 
extension of a spring arm that extends toward the rotational axis of the 
armature and parallel to the axis of the coil and which has its sheet 
metal plane extending parallel to the base plane. The terminal webs and 
the fastening tabs that are connected thereto preferably encompass the 
center contact terminal pins. This contributes to a good accessibility of 
the fastening points and to an improved adjustment of the contact 
clearance. Preferably, the connection between the fastening tab and the 
center contact terminal pins occurs through resistance welding or laser 
welding. During the assembly, the relay spring group can be introduced 
into the base body together with the armature respective to the base body 
or pedestal from above with the help of the fastening tabs that have their 
sheet metal plane directed perpendicular to the base plane. When a desired 
contact clearance is reached, the contact spring group is fastened to the 
base body together with the armature. When, during the installation, the 
contact spring group is intentionally introduced into the base body with 
the armature at an angle in a longitudinal direction, then a mechanical 
monostability of the relay can be preset. This is possible, for example, 
by choosing a smaller contact clearance at the break contacts than at the 
make contacts. 
For the purpose of reducing the number of necessary relay component parts, 
the contact springs, which include the connecting webs, the terminal webs 
and the fastening tabs, are preferably fabricated from a common sheet of 
metal. The same is valid for the terminal tracks for the stationary 
contact elements, whereby the terminal elements are formed by terminal 
tabs of the metal sheet that are bent off perpendicularly. 
In an advantageous embodiment of the invention, the envelope of the contact 
spring group exhibits a receptacle for the armature, so that the relay 
armature can be arranged insulatingly between the contact springs. Thus, 
the relay armature is either glued to the envelope of the contact spring 
group or it is connected by deformable, vertical pegs of the envelope with 
the contact spring group. Preferably, the relay armature is fashioned 
planar, so that a coupling piece is arranged between the armature and the 
at least one permanent magnet for the reduction of the magnetic resistance 
in the magnetic circuit. This coupling piece can either be fastened to the 
magnet by laser welding or can be held in the envelope of the coil. An 
additional reduction of the overall height of the relay results when the 
armature, from its center area, is bent toward the pole shoes by roughly 
half of the lifting angle. 
Advantageously, the coil, together with the core and the pole shoes, is 
surrounded by an insulating envelope and a pedestal of the relay is 
fashioned by the base body, which accepts the armature and the contact 
spring group so that the insulating envelope together with the bottom side 
of the pedestal form a housing for the relay. When finishing such a relay, 
the coil that is surrounded by the insulating envelope is pushed onto the 
pedestal until the desired armature stroke is reached. Thus, the 
insulating coating of the coil clamps on the pedestal and the relay can be 
subsequently sealed with a casting resin. 
Other advantages and features of the invention will be readily apparent 
from the following description of the preferred embodiments, the drawings 
and claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A relay of the present invention is illustrated in FIG. 1 and has a housing 
which is constructed on the bottom side of a pedestal or base, generally 
indicated at 1, and by an insulating envelope 56 of a coil 5, which 
envelope is pushed over the base 1. Preferably, the envelope 56 is 
fashioned by extrusion-coating of the coil 5. Contact terminal elements 11 
and winding terminal elements 51 extend through the bottom side of the 
base 1 that represents the base plane of the relay. A contact spring group 
2 and an armature 4 are arranged above the base 1 and below the coil 5, 
and are best illustrated in FIG. 2. The contact spring group 2 has an 
envelope 3 that is composed of insulating material, in which two contact 
springs 20 are embedded to lie parallel to one another in a common plane. 
Preferably, the envelope 3 is fashioned by an extrusion-coating of the 
contact springs 20. Each contact spring 20 comprises a connecting web 22, 
which is best illustrated in FIG. 3, and two spring arms 21. Contact 
making ends of the spring arms 21 extend out of the envelope 3, as best 
illustrated in FIG. 2, and the spring arms 21 have contact pieces or pads 
25 of a profile material welded on their ends. The parts of the spring 
arms 21 that are embedded in the envelope 3 directly merge into the 
connecting webs 22, as illustrated in FIG. 3. In addition, the envelope 3 
exhibits a receptacle for the armature 4, namely the armature is arranged 
and insulated between the relay springs 20 and secured thereto. 
A core 53 (FIG. 1), to whose end pole shoes 54 are directed toward the 
armature 4 to form a connect, is arranged axially in the coil 5. A 
bar-shaped three-pole permanent magnet 6 is arranged parallel to the axis 
of the coil between the pole shoes 54 to generate like polarizations S at 
the ends of each pole shoe 54. 
In order to reduce the magnetic resistance between the armature 4 and the 
permanent magnet 6, a coupling piece 41 is arranged between the armature 
and the magnet 6 in the area of the rotational axis of the armature. Given 
a relay according to FIG. 1, the terminal elements 11 for the relay 
elements 14 and 25 can be realized as surface mounted technology-terminal 
contacts or SMT-terminal pads or contacts. On principle, they can also be 
fashioned as insert pins. 
A base or pedestal 1 that is composed of insulating material has terminal 
tracks 13 for stationary contact elements 14 that are manufactured by a 
common sheet of metal being embedded in the base. The stationary contact 
elements 14 are welded on the terminal tracks 13. The contact terminals 11 
are fashioned by bending down tabs of the common metal sheet for the 
terminal tracks 13, as best illustrated in FIG. 3. The same is valid for 
the center contact terminals, which are also fashioned by bending terminal 
tabs of the terminal tracks. The center contact terminal pins 12 are 
fashioned by terminal tabs that are bent upward, while the terminal 
elements 11 of the center contacts are bent downward and extend through 
the bottom side of the base 1. 
With the help of FIGS. 2 and 3, it can be seen that the contact spring 
group 2 comprises two contact springs 20, which are separated from each 
other and extend parallel to each other and that they carry switch 
contacts 25 that are welded on their spring arms 21. The contact springs 
20 are preferably formed from a common sheet of metal and are surrounded 
in their center section by an insulating envelope 3. Apart from the 
contact making ends of the spring arms 21, two transverse terminal webs 23 
extend out of the envelope 3 in the area of the rotational axis of the 
armature, and have their sheet metal plane extending perpendicular to the 
base plane. The terminal webs 23 are respectively connected via a leaf 
spring web with the spring arm 21 of the contact spring 20. Thus, the leaf 
spring web represents an extension of the spring arm 21 that extends 
parallel to the axis of the coil to the area of the rotational axis of the 
armature and which has its sheet metal plane extending essentially 
parallel to the base plane. Moreover, the contact spring group 2 exhibits 
two fastening tabs 24, which have their sheet metal plane directed 
perpendicular to the base plane. The fastening tabs 24 are respectively 
fastened to the center contact terminal pins 12, which extend 
perpendicular out of the base 1 and are connected to the contact spring 20 
via the terminal webs 23. In addition, the height of the vertical terminal 
webs 23 increases ramp-like up to the fastening tab 24 from the side that 
faces the armature 4 and, thus, the webs 23 slope outwardly from the 
contact spring 20. The connecting web 22 is surrounded entirely by the 
insulating envelope 3 and has its sheet metal plane directed perpendicular 
to the base plane, as shown in FIG. 3. 
Since the center contact terminal pins 12 and the fastening tabs 24 have 
welding surfaces, which lie next to each other in a plane that is 
perpendicular to the base plane, the contact spring group can be 
introduced into the base 1 together with the armature 4 from above during 
the assembly operation. When a desired contact clearance is reached, the 
fastening tabs which engage the center contact terminal pins 12 together 
with the terminal webs 3 are welded on the welding surfaces of the center 
contact terminal pins 12. The contact pieces 25 that are welded on the 
contact making ends of the spring arms 21 respectively overlap two 
stationary contact elements 14. The ends of the armature 4 are bent 
slightly upward toward the pole shoes 54 to contribute to an additional 
reduction of the overall height of the relay. 
In addition, during assembly, the desired armature stroke is easily 
adjustable. To that end, the coil 5, as well as the core 53 and the pole 
shoes 54 that are also surrounded by the insulating envelope 56, as well 
as the permanent magnet 6 that is arranged below the coil 5, are pushed 
onto the pedestal or base 1 that is equipped with the contact spring group 
2 and the armature 4 until the desired armature stroke is obtained. 
Thereby, the envelope 56 of the coil has its bottom edge clamped on the 
base. With the help of a magnetic equalization, it is ensured that the 
relay will respond to the desired voltage. 
Although various minor modifications may be suggested by those versed in 
the art, it should be understood that I wish to embody within the scope of 
the patent granted hereon all such modifications as reasonably and 
properly come within the scope of my contribution to the art.