US2867756A - Electromagnetic relay - Google Patents

Description

Jan. 6 1959 G. MAKowsKl ELECTROMAGNETIC RELAY Filed April 26. 1956 United States Patent ELECTROMAGNETIC RELAY Giinther Makowski, Munich, Germany, assigner to Siemens & Halske Aktiengesellschaft, Berlin and Munich, Germany, a corporation of Germany Application April 26, 1956, Serial No. 580,883

lClaims priority, application Germany May 10, 1955 4 Claims. (Cl. 317-187) This invention is concerned with an electromagnetic relay comprising means for locking its armature in operated position.

Various interlocking relays of the a-bove-noted general character have become known. Some of these structures are provided with special link controlled locking niembers or with several armatures, one armature acting as a locking means for the other armature; other structures provide permanent magnets in the iron path or omit the usual residual stud on the armature so as to eiiect retention thereof in operated position. The two first mentioned structures require relatively great expenditure for auxiliary parts and in some cases greater operating energy; in the two last-mentioned embodiments, the actuation is adversely affected by jarring and by contamination of the core and armature surfaces.

The object of the invention is to provide a reliably operating interlocking relay requiring small expenditure so far as auxiliary parts are concerned and which does not require higher operating energy than a relay of the customary normal type. This object is realized by the provision of a non-magnetic hooklike latch or locking member which is pivotally disposed at the free armature end facing the air gap, such latch member carrying a permanent magnet.

Details of the invention will appear from the description of an embodiment which is rendered below with reference to the accompanying drawing showing in schematic manner only relay parts required for an understanding thereof. In the drawing,

Fig. l shows the new structure partially in section and with the parts in normal position; and

Fig. 2 shows the structure in locked position.

At the free end of an armature 1 is disposed a hooklike latch member 3 which is pivoted at 2. The latch 3 carries a permanent magnet 4. The area of pivotal motion of the latch 3 is in one direction limited by a stop 5 and in the other direction by the end 6 of the armature. It is however possible to form the means which hold the permanent magnet on the latch 3 so that they define the limit positions thereof.

In the normal position of the corresponding relay, with the armature restored, the permanent magnet 4 will be within the stray magnetic eld of the electromagnet of which only the core 7 is shown in the drawing. Upon energization of the relay, the armature 1 will be attracted to the core 7 until the residual member 8 is in engagement therewith. The stray magnetic iield increasingly aiects the permanent magnet 4 on the latch 3, during the attraction of the armature, and such magnet is accordingly likewise attracted by the core 7 and rotates the latch 3 counterclockwise from the position shown in Fig. l to the interlocking position shown in Fig. 2, the angular free end 9 of the latch engaging over the end of the core 7 as shown in Fig. 2. Upon interruption of the energizing current for the corresponding relay, the

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armature 1 will remain locked in operated position due to the interlock between the latch extension 9 with the core '7. Any small idling displacement of the armature toward normal-or released position thereof, incident to interruption of the energizing current, will merely be by an amount just suricient to allow the latch extension 9 to engage the core 7; such fractional idling displacement will not atect the relay contacts.

The armature release is effected by exciting the correspending relay winding in a sense opposite to the operatively eiective energization thereof, thereby polarizing the core 7 likewise in opposite sense. The armature 1 is now attracted `by the small amount of its fractional restoring motion responsive to interruption of the energizing current, and inasmuch as the permanent magnet 4 is now of the same polarity :as the core v7, it will be repelled, causing clockwise rotation of the latch 3 to retract the extension 9 from interlocking engagement with the core 7. The energy required for the excitation of the relay winding in opposite sense to its operatively eiective excitation, to eifect restoration of the armature, is lower than the energy required for the attraction thereof.

Changes may be made within the scope and spirit of the appended claims.

I claim:

l. In an electromagnetic relay having a core and a movable armature the free end of which is in normal position spaced by an air gap from the free end of the core, a device for holding the armature in attracted position after attraction thereof responsive to energization of said core, said device comprising a non-magnetic latch member rotatably mounted at the free end of said armature, and a permanent magnet carried by said latch member and forming a unit therewith, the polarization of said permanent magnet being in a sense opposite to the polarization of said core resulting in the energization thereof to effect attraction of said armature, so as to cause incident to the attraction of said armature attraction of said permanent magnet and consequently rotation of said latch member to place such latch member in interlocking engagement with said core.

2. A structure and cooperation of parts according to claim 1, comprising stop means for defining the limits of rotary motion of said latch member.

3. A structure and cooperation of parts according to claim 1, comprising a residual member disposed between said armature and said core, the width of said air gap exceeding in holding position of said armature the thickness of said residual member.

4. A structure and coperation of parts according to claim l, wherein release of said armature is effected by energization of said core in a sense opposite to the sense of energization thereof to elect attraction of said armaure, for the purpose of causing polarization of said core corresponding to the polarization of said permanent magnet, whereby said permanent magnet is repelled from said core so as to rotate said latch member to normal, thereby breaking the interlocking engagement of such latch member with said core and permitting release of said armature.

References Cited in the file of this patent UNITED STATES PATENTS 2,343,199 Mayer Feb. 29, 1944 FOREIGN PATENTS 2,930 Great Britain Feb. 6. 1901

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