Miniature magnetic latch relay

#This invention relates to a relay structure, and more particularly to an improved miniature magnetic latch relay of simplified construction.

#Permanent magnet latching relays, which employ a permanent magnet to provide a latching function in both of two alternate contact positions, have been used in various configurations and more recently in microminiature size. A problem experienced with permanent magnet latching relays, and especially those relays of microminiature size, is the intricate and costly assembly of numerous parts requiring precise alignment and fastening techniques. There is significant need in the electronics industry for this type of relay in a number of important uses and applications, with the requirements of low cost and reliable operation. Accordingly, it would be highly desirable to provide a compact, microminiature permanent magnet latching relay having substantially fewer parts thereby significantly simplifying mechanical assembly resulting in lower manufacturing costs and high reliability.

#The principal object of this invention is to provide an improved miniature magnetic latch relay.

#FIG. 1 is a sectional view with parts shown in elevation of a minature magnetic latch relay according to the present invention and taken along lines 1--1 in FIG. 2;

#FIG. 2 is a perspective view with parts removed of the miniature magnetic latch relay according to the present invention;

#FIG. 3 is a perspective view of the frame included in the relay of FIGS. 1 and 2;

#In basic miniature magnetic latch relay structures, an armature is in pivotal contact with a permanent magnet having a pivot edge formation on one end, and the armature and permanent magnet are carried by a support header which includes current-carrying terminal pins extending therethrough, at least one pair of fixed contacts electrically coupled to corresponding ones of the terminal pins, and a movable contact electrically coupled to another one of the pins, in operative association with the armature, normally engaging one of the fixed contacts, and adapted for movement into engagement with the other of the fixed contacts in response to pivotal movement of the armature. The armature is held in either of two stable positions by flux from the permanent magnet thereby placing the movable contact in engagement with one of the fixed contacts. The armature is pivoted to the other of the stable positions by selective energization of a pair of electromagnetic coils carried by the header thereby placing the movable contact in engagement with the other of the fixed contacts.

#In accordance with the present invention, a frame is provided having a main body portion spaced from the header and in close relation to the armature, a pair of spaced-apart pole piece sections of magnetic material in the main body portion and operatively associated with the armature, a pair of spaced-apart supporting legs extending from the main body portion toward the header and fixed to the header, a pair of core sections of magnetic material extending from the main body portion in a direction away from the header through the coils and fixed to a yoke of magnetic material spaced from the main body portion and fixed to the other end of the permanent magnet, an opening in the main body portion through which the one end of the permanent magnet extends for pivotal contact with the armature, and a barrier of non-magnetic material in the main body portion surrounding the opening. The barrier has sufficient reluctance to resist the flow of magnetic flux between the permanent magnet and the main body portion thereby forcing magnetic flux to flow between the permanent magnet and the armature. The armature has a groove in the surface facing the permanent magnet for receiving the pivot edge formation of the magnet in a manner allowing pivotal movement. The main body portion of the frame is provided with armature retention means in the form of a pair of tabs extending from opposite sides of the frame and either a single pin fixed to both tabs or a pair of pins fixed to corresponding ones of the tabs, the single pin or pair of pins extending in closely spaced relation to the surface of the armature facing the header. The armature retention means retains the pivot edge formation of the permanent magnet in the armature groove under vibratory and shock load conditions by virtue of the pin to armature surface spacing being less than the depth of the armature groove. The length of the armature groove is less than the width of the armature thereby restraining relative lateral movement between the armature and permanent magnet. The pivot edge formation on the end of the permanent magnet is provided by a pair of surfaces disposed at acute angles to the magnet longitudinal axis and meeting to define the pivot edge, and these surfaces meet a corresponding pair of surfaces extending outwardly therefrom in a direction substantially perpendicular to the magnet longitudinal axis thereby enhancing the coupling of magnetic flux from the permanent magnet to the armature.

#Referring to the drawings, the miniature magnetic latch relay 10 comprises several principal assemblies or elements including a motor assembly which comprises a pair of coils carried by the magnetic portion of a frame, an armature assembly, a permanent magnet assembly, and a header assembly which contains switch contact elements and terminal pins on a supporting base.