US 3750060 A
An electromagnetic relay in which center contact spring means normally engages outer contact spring means on one side and is moveable into engagement with contact spring means on the other side upon energization of an electromagnetic actuator forming a part of the relay. The contact spring means are in the form of leaf springs having contact elements at one end and being supported near the other end by a block of electrical insulating material having lateral slits into which the spring means are inserted. The slits are inclined relative to each other and thereby predetermine the preload on the individual spring means. The block has at least one wall portion projecting therefrom which has abutment elements interposed between the center spring means and the outer spring means to limit the movement of the latter toward the former. Advantageously, each contact spring means is in the form of a pair of laterally spaced springs between which the aforementioned wall is disposed.
Description (OCR text may contain errors)
United States Patent 1 Pfenning 1 July 31, 1973 ELECTROMAGNETIC RELAY  Inventor: Hans Pfenning, Lauffen, Germany  Assignee: Bach & Co., Heilbronn, Germany  Filed: Apr. 20, 1972 ] Appl. No.: 245,739
 A Foreign Application Priority Data Apr. 22, 1971 Germany" P 21 1? 734,2
 US. Cl. 335/135, 200/166 J  Int. Cl. 1101b 63/04  Field of Search 335/135; 200/166 .1
 References Cited UNITED STATES PATENTS 3,256,401 6/1966 Dawson 335/135 FOREIGN PATENTS OR APPLICATIONS 5/1962 7 Austria 335/135 Primary Examiner-Harold Broome Att0rneyWalter Becker  ABSTRACT An electromagnetic relay in which center contact spring means normally engages outer contact spring means on one side and is moveable into engagement with contact spring means on the other side upon energization of an electromagnetic actuator forming a part .ofthe relay. The contact spring means are in the form of leaf springs having contact elements at one end and being supported near the other end by a block of electrical insulating material havinglateral slits into which the spring means are inserted. The slits are inclined relative to each other and thereby predetermine the preload on the individual spring means. The block has at least one wall portion projecting therefrom which has abutment elements interposed between the center spring means and the outer spring means to limit the movement of the latter toward the former. Advantageously, each contact spring means is in the form of a pair of laterally spaced springs between which the aforementioned wall is disposed.
5 Claims, 3 Drawlng Figures PATENIEU JUI. 3 1 I915- ELECTROMAGNETIC RELAY The present invention relates to an electromagnetic relay with a contact spring set which comprisesat least three contact springs that are approximately parallel to each other. The intermediate contact spring of the relay is on both sides provided with contact elements and rests under an elastic preload against the inn'er'contact spring which is'adjacent to the armature of therelaylThe intermediatecontact spring isby means'of the armature lifted in response to the armature being attracted and is pressed against the outer counter contact. Finally, the relay is provided withan auxiliary holding device for connecting and insulating the contact springs. With contact spring sets of heretofore known electromagnetic'relays, stamped out hard paper plates are provided for insulating and connectingthecontact springs. These hard paper plates arealternately with the-contact springs stacked on'e upon the other, and then by means of screws vertically cr'ossing'the layers or by meansot' rivets the hard pape'r platesarefirmly pressed against the'i'ron core of the relay orasupporting body. In addition thereto,- it is known for purposesof obtaining the necessary contact pressure, as it is're'quired in rest position of'the, relay, to provide wedge-shaped intermediate layers between the contact springs which layers will assure the prelo'ad for the contact springs:
Witht'hese known'arr'ang'ements, the assembly and installation of the individual elements pertaining to'the contact spring'set require considerable time. Thistime requirement increases w'ith'the increase in th'enumber of the Contact springs pertaining toa" contact spring set.
elements which in the rest position of the relay under an elastic preload rest'against the'inner c'ounter contact spring which is adjacent to the armatureof therelay and which is lifted off in response to the energization of the relay and is pressed againstthe outer counter contact. In this instance not only the contact pressure generated at the-inner counter contact will have to be assured in its rest position; but also a sufficient counter pressure must be obtained'if the intermediate contact spring in the working position 'of the relay is pressed against the outer. counter contact; A further difficulty frequently consists in that during the mutual engagement and disengagement of the contact elements arranged on the intermediate contactspring and on one of the counter contact springs, a low sliding frictidn is to be created which will eountei-acrthe formation'of oitidicfilms or skins and makes it necessary that the counter contact springs slightly yield under contact pressure exerted by the intermediate spring andca'n es pi r With a heretofore known arrangement of this type, pressed parts of insulating material are provided for a contact spring set. These pressed parts of insulating material are alternately stacked with the contact springs and inthis connection generate the preload necessary for the contact forks between the individual contact springs, the preload" resulting from clamping the contact springs together; In order to: obtain the-desired alignment of the contact springs duringthe assembly, according to this known arrangement corresponding to themost recent state of. the art, two parts pressed of synthetic material which embrace a contact spring therebetween are provided with protruding: noses, while another oppositely located pressed part is provided with correspondingreces'ses; the noses. extending through two bores in the contact spring. Since, however, with this known arrangement it-is necessary to provide a number of different pressed parts of insulating material in order to take into consideration the different spacing between the contact springs and to generate thev tension forces necessary in theposition of'operation, the assembly can be effected only manually while great care has to be taken in this connection.
Moreover, not only a corresponding thorough work control is necessary, but the necessary formed or molded parts have to be kept in stock in great numbers for the manufacturing processand also-for a possible replacement. I i I 1v Itis; therefore, an object of the present invention so to design 1 the relay, which comprisesa contact spring 'set including at least three contact; springs, that the assembly will be greatly facilitated while the necessary contact pressure will be assured in the rest position of the intermediate contact spring and also in the' working position of this c'ontac't spring. '1
This object and other objects and advantages of-the invention will appear moreclearly from the following specification in connection withv the'accompanying drawing, in'whichz v v FIG. l shows a relay accordingto thepresent invention asseen from the side and at a scale whichcorrehas at least three slits or cuts respectivelyreceiving one contact spring each which are inclined relative to the base surface ofthe insulating block and the inclination of which determines the elastic preloadof the contact springs. The insulating block furthermore is provided with at least two supporting arms extending in" a direction transverse to thecontact springsrone of thesupporting arms forming an abutment for the outer counter contact spring, whereas the other supporting arm serves for engagement with the inner contact spring."
In order to assure thatfor purposes of obtaininga slight contact friction the two counter contact springs will be able under'the pressure of the intermediate contact spring slightly to yield, it issuggeste'd according to a further development-of the invention to arrangethe supporting arms in the space between 'theinte'rmediate contact springand the twocounter contact springs. Inas'much as the insulating block is expediently made in the form of a pressed member ot synthetic material, the desired preload under which the counter contact springs, in view of the inclination of the slits or cuts receiving same, are directed against the supporting arms may be obtained without any post-adjustment merely by connecting the supporting arms to the insulating block by making them one piece therewith. With such a design of the insulating block it is particularly advantageous to mount the supporting arms on a wall formed onto the insulating block which wall in the longitudinal direction of the contact springs and at least approximately parallel thereto protrudes from the insulating block. Such wall will assure not only the spacing of the supporting arms and their counter springs from the intermediate contact spring but will also protect the en- .tire counter spring set against mechanical damage which may occur when mounting the relay in a larger unit and may also occur during a later checking operation.
The invention may advantageously be employed with such electromagnetic relays in which the contact spring set is equipped with contact springs of which each two are arranged in a common plane adjacent to each other. f each two contact springs located in the same plane adjacent to each other, one spring belongs to one of two contact sets whereas the other spring belongs to another one of two contact sets. These contact sets may preferably be designed as reversing contact sets. In such an instance a particularly simple but stable symmetrical construction of the contact spring set may be realized by providing the insulating block for each of the contact springs with one of two cuts or slits which are located in the same plane and extend from two oppositely located block sides to the vicinity of another cut or slit while maintaining an intermediate Web for holding the block together. If in the above mentioned manner as support for the supporting arms there is provided a wall formed onto the insulating block, it is possible with a symmetrical construction to obtain a very advantageous and complete contact protection when the formed-on wall between the two contact sets respectively forming a group forms an extension of the intermediate web of the insulating block. For simple relay constructions it is desired for returning the relay armature to its disengaged position not to have to provide special return springs. It is rather desired to take advantage of the returning force of the movable contact spring or contact springs by providing between the movable contact spring or springs and the armature a plunger stud which has one end resting against the contact spring or springs and has its other end resting against an extension which preferably protrudes at a right angle from the armature. In such an instance the wall formed onto the insulating block as support for the supporting arms affords the possibility to provide in this wall a groove-shaped cutout for guiding the plunger stud.
Referring now to the drawing in detail, the illustrated miniature relay has arranged on the pressed body of synthetic material a fine wire coil 11, and an iron core 12 extending through the coil, which core protrudes at one coil end beyond the body 10 and at its other end is riveted to an angle member 13 forming a part of the iron core. The longer leg 14 of the angle member 13 has its end section designed to form a knife edge bearing 15 for a movable hinged armature 16 which is secured on the'edge of leg 14 by means of a holding plate 17. The'contact spring set forming a compact construction group is connected to the leg 14 by a holding screw 18 extending all the way through. This contact spring set 20 is symmetrically arranged with regard to a plane located in the axis of the coil 11 and of the iron core 12 as indicated in FIG. 2 by the line A A. One of two contact sets B and C is arranged on one side of the plane of symmetry while the other one of these contact sets is arranged on the other side of the plane of symmetry. Each of the contact sets B and C comprises an intermediate contact spring 22 coupled to the armature 16 by the plunger stud 21, and two counter contact springs, namely the inner contact spring 24 and the outer contact spring 25. FIG. 1 shows only that one of these contact springs which pertains to the contact set B. The contact set C is built up in a corresponding manner.
, In order to permit an easy assembly of the contact springs and to assure a high stability of the contact spring sets, there is provided a one-piece block 26 of insulating material having formed thereonto a supporting wall 27 located in the plane of symmetry A A. This supporting wall 27 extends perpendicularly to the leg 14 of the angle member 13 of iron and protects the two contact sets B and C against mechanical damage while protecting the contact sets B and C electrically against sparking or the like. For purposes of receiving the contact springs, the insulating block 26 has in a common plane two cuts or slits each which extend from two block sides 28 and 29 located opposite to each other to the vicinity of the respective other slit or cut while leaving an intermediate web to assure the coherence of the block. The supporting wall 27 is located along the extension of this web. These cuts are shown in FIG. 3 for the contact set B and are designated with the reference numerals 31, 32 and 33, and are also shown for the contact set C and are designated with the reference numerals 34, 35 and 36. The slit 31 intended for receiving the outer contact spring 25 is inclined with regard to the base surface 40 of the insulating block 26 which base surface is provided with two plug studs 37 and 38 in such a way that the contact spring 25, when being inserted into the slit, will automatically obtain the necessary preload which, when energizing the relay, will assure a proper contact with regard to the intermediate contact spring 22 which is then moved by the hinged armature 16 through the plunger stud 21.
For purposes of precisely fixing the outer contact spring 25, there is according to the present invention provided a supporting arm 41 for the contact spring 25. The contact spring 25 rests on the supporting arm 41 at the preload resulting from the inclination of the slit 31 whereby the contact spring 25 is fixed in its proper position for making a contact. In an analogous manner,
the slit 33 intended for receiving the lower and inner counter contact spring 24 ascends upwardly and is associated with a second supporting arm 42. The inner counter contact spring 24 rests from below under a preload against the second supporting arm 42 when the intermediate contact spring 22 starts to lift itself off with its lower contact element 43. The supporting arm 42 then will determine the precise location of the intermediate contact spring 22 at which the connection to the contact member 44 will be disengaged. In a corresponding manner, the inclination of the slit 32 intended for the intermediate contact spring 22 is directed slightly upwardly and will then generate the contact pressure between the contact members 43 and -44 which is also necessary in the rest position of the relay.
Numerals 45 designate the contact elements on contactsprings 25.
in conformity with the symmetric construction of the contact spring set, also for the two counter contact springs of the contact set C (FIG. 2 showing only the outer contact springs 25) there are provided two supporting arms 46 and 47. These supporting arms 46 and 47 will similar to the supporting arms 41 and 42 make it possible that during the making of contact their pertaining contact springs can slightly yield under the control pressure so that at the contact surfaces there will be obtained a slight sliding friction which will assure a permanent satisfactory making of contact. Simulta neously, the supporting arms will fix the engaging and disengaging position. In this way, in spite of the small dimensions of the miniature relay, a safe determination for the control behavior of the relay will be obtained.
The supporting wall 27 is for purposes of guiding the plunger stud 21 provided with a groove-shaped cutout 50. The plunger stud 21 can be moved upwardly in the cutout 50, when the relay is energized to such an extent that its lateral extensions 51 can press the intermediate contact springs 22 against the outer counter contact springs 25.
lt is, of course, to be understood that the present invention is, by no means, limited to the particular showing in the drawing but also comprises any modifications within the scope of the appended claims.
What is claimed is:
1. In an electromagnetic relay, a contact spring assembly comprising: ribbon-like center contact spring means and outer contact spring means arranged in generally parallel superposed spaced relation, holding and insulating means supportingly engaging said spring means in a region near one end and interengageable contact element means on said spring means near the other end, an'electromagnetic actuator having a frame connected to said holding and insulating means adjacent one of said outer contact spring means, said center contact spring means normally holding the contact element means thereon in engagement with the contact element means on said one'outer contact spring means,
said electromagnetic actuator having an armature operatively connected to said center contact spring means and operable when energized to move said center contact spring means to cause the contact element thereon to separate from the contact means on said one outer spring means and to engage the said contact means on the other outer spring means, said holdingand insulating means having separate slits receiving said regions of said contact spring means, said slits being inclined to each other to predetermine the elastic preload on said contact spring means, and abutment elements engageable with said outer contact spring means to limit the movement of said outer contact spring means toward said center spring means, said abutment elements protruding into the space betweensaid center contact spring means and respective ones of said outer contact means, and being formed in one piece with said holding g 6 and insulating means.
2. Anelectromagnetic relay according to claim 1 in which said holding and insulating means comprises at least onewall portion substantially parallel to said contact spring means, said abutment elements being integral with said wall portion and protruding therefrom into the space between said center contact spring means and. respective ones of said outer contact spring means.
3. An electromagnetic relay according to claim 1 in which each of said center andouter spring means comprise a pair of springs in laterally spaced relation, said holding and insulating means having a said slit for each spring extending inwardly from the respective side of said holding and insulating means, the central portion of said holding and insulating means between the respective slits for each pair of springs being uninterrupted. v
4. An electromagnetic relay according to claim 1 in which each of said center and outer spring means comprise a pair of springs in laterally spaced relation, said holding and insulating means having a said slit for each spring extending inwardly from the respective side of said holding and insulating means, the central portion of said holding and insulating means between the respective slits for each pair of springs being uninterrupted, a wall portion integral with said central portion of said holding and insulating means and extending outwardly therefrom in the space between the respective springs of each pair of contact spring means, said abutment elements being integral with said wall portion and protruding in the lateral direction therefrom into the spaces between the respective springs of said pair of center contact spring means and the respective springs of said pairs of outer contact spring means.
5. An electromagnetic relay according to claim 1 in which .each of said center and outer spring means comprise a pair of springs in laterally spaced relation, said holding and insulating means having a said slit for each spring extending inwardly from the respective side of said holding and insulating means, the central portion of said holding and insulating means between the respective slits for each pair of springs being uninterrupted, a wall portion integral with said central portion of said holding and insulating means and extending outwardly therefrom in the space between'the respective springs of each pair of contact spring means, said abutment elements being integral with said wall portion and protruding in the lateral direction therefrom into the spaces between the respective springs of said pair of center contact spring means and the respective springs of said pairs of outer contact spring means, said wall portion comprising a cutout facing said electromagnetic actuator, and plunger means reciprocably guided in said cuto'ut and disposed between said center contact spring means and the armature of said electromagnetic actuator and forming the operative connection of said armature to said center contact springs.
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