US2911493A - Miniature relay for high switching frequencies - Google Patents

Description

Nov. 3, 1959 K. WEBER EI'AL MINIATURE RELAY FOR HIGH SWITCHING FREQUENCIES Filed Jan. 21. 1958 2 Sheets-Sheet 1 FF? FT w J 3nnentors ,ITQrre/Z/e; ZbAza/arE/va Nov. 3, 1959 k. WEBER ETAL 2,911,493 1 MINIATURE RELAY FOR HIGH SWITCHING FREQUENCIES- Filed Jan. 21, 1958 2 Sheets-Sheet z ntora United States Patent RELAY FOR HIGH SWITCHING FREQUENCIES Application January 21, 1958, Serial No. 710,250

' Claims priority, application Czechoslovakia January 22, 1957 6 Claims. (Cl. 200-87) MINIATURE Numerous attempts have already. been made to obtain a 'suitable miniature relay for telephonic and other purposes, which attempts failed owing to the fact that the reduction of the size of the component parts of the relay weakened the whole structure of the relay to such an extent that it could not withstand the service strain even undernorrnal conditions. In those cases where the duty in operation is particularly heavy, such as, for example, in the case of teleprinters, where the relay is operated up to 25,000 and even more times per hour and where even normal telephonic relays do not function satisfactorily, the use of miniature relays could not be considered, although the reduction of size in the relays in such apparatuses would be very useful.

Accordingly, it is an object of the present invention to provide a miniature relay presenting such a high switching frequency and other properties that it is adapted for use as a normal relay for telephonic and similar purposes, but is even satisfactory for the heavy-duty operations occurring in teleprinters and similar installations. More specifically, the relay according to the present invention presents such a high switching frequency as to carry out conveniently the above mentioned 25,000, and even more, switching operations per hour commonly required in teleprinters and the like, and its durability, when subjected to such heavy duty, exceeds by far the durability of a normal telephonic relay under similar working conditions.

The desired durability with greatly reduced dimensions of the relay is achieved in accordance with the present invention by pivotally mounting the armature lever of the relay, and by causing its driving end to act on rigid rodlike extensions of helically wound springs which are fixed in such a way as to ensure that, in a rest position with the driving end of the armature lever spaced from the rodlike extensions, the contact ends of the rodlike extensions bear only with the initial tension of the springs against the corresponding twin counter-contacts, while in the other position, i.e. in working position, the extension of each helically wound spring forms a rigid lever pivoting about the driving end of the armature lever in such a way that the tension of the spring causes the contacts to roll on the twin counter-contacts which are supported either flexibly or rigidly on a rigid carrier.

The accompanying drawings illustrate, merely by way of example, a miniature relay having a high switching frequency and constructed in accordance with an embodiment of the present invention.

'In the drawings:

Fig. 1A is a side elevational view of the miniature relay embodying the invention;

Fig. 1B is an end elevational view of the relay;

Fig. 1C is a bottom plan view of the relay; and

Figs. 2 and 3 are enlarged detail views showing the contacts of the relay in the deenergized and energized conditions of the latter.

Referring in detail to Figs. 1A, 1B and 1C, it will be seen that the miniature relay according to the present invention consists of a coil 1 with terminals 2 which is fixed 2,911,493 Patented Nov. 3, 1959 "ice on a frame in the form of an angle 3 of soft iron. The angle 3 has a leg 3a extending parallel to the axis of coil 1 along the latter and a spindle 4 is held in place at the end of leg 3a. The spindle 4 has hardened ends received in bearing eyelets of a bent lever 5 which is generally U-shaped (Fig. 1B) so as to include a transverse member 5a and depending legs 5b, and the transverse member 5a is extended over the adjacent end of coil 1 and carries the armature 6 of therelay. A holder 7 of an insulating material is also fixed to the angle leg 3a and supports helically wound springs Shaving their axes extending generally parallel to the leg 3a. Leaf springs 9 backed by fixed metal strips 10 are also supported by holder 7 at the sides of springs 8 facing away from angle leg 3a. Countercontacts 11 are fixed to the lower or free ends of leaf springs 9, while the upper or other ends 12 of the springs 9 project. short distances above holder 7 and are in the form of terminals.

A rigid rodlike extension 13 projects axially from the lower or free end of each helical spring 8 and has a widened contact 14 at the end remote from the related spring. A transverse driving member 15 extending between the legs 5b of the lever 5 bears against the extensions 13 during the movement of lever 5 from the rest position into the energized position. In the rest position of the lever '5 (Figs. 1A, 1C and 2), the contacts 14 fit against counter-contacts 16 which are provided with terminals or posts 17 and fixed on an insulating piece 18 secured to the iron angle 3.

Figs. 2 and 3 illustratethe positions of the springs 8 in the deenergized and energized conditions, respectively, of the relay. When the lever 5 is in its deenergized or rest position, each spring 8 urges the related movable contact 14 against the counter-contact 16 merely through its initial tension which is imparted to the spring when being secured in holder 7. When the relay is energized, lever 5 rocks in the counter-clockwise direction, as viewed in Fig. 1A, and the transverse member 15 acts against each rigid extension 13 intermediate the ends of the latter so that extension 13 rocks or turns on the transverse member 15 and forms a rigid lever carrying at its free end the contact 14 whereas the other end of the extension 13 is acted upon by the tension of the related spring 8 urging the movable contact 14 against the counter-contact 11. The counter-contacts 11 and Marc preferably twin-contacts, as shown in Figs. 1A and 1C, that is, have two converging, arcuate contact surfaces, while the movable contact 14 has a cylindrical surface adapted to simultaneously engage both arcuate contact surfaces of the related counter-contacts 11 or 16 and to roll on such contact surfaces during rocking of the extension 13. Alternatively, as shown in Figs. 2 and 3, the movable contact 14 may have a surface that is convex both in the direction of its axis as well as circumferentially. In Figs. 2 and 3, only one contact surface of each of the counter-contacts 11 and 16 has been shown merely for the purpose of better illustrating the contact between the movable contact and associated counter-contacts. The counter-contacts 11 may be resiliently mounted, for example, on the leaf springs 9 as in Figs. 1A, 1B and 1C, while the countercontacts 16 are rigidly supported, or both sets of countercontacts may be mounted on a fixed rigid carrier, as the helically wound spring 8 itself is adequate for equalizing any unevenness which may occur in the fitting of the contact 14 against the counter-contact 11. Since the transverse member 15 displaces each extension 13 through a greater distance than is necessary for bringing about mere contact between the contact 14 and the counter-contact 11 for the purpose of ensuring a perfect contact therebetween, the extension is rocked and the contact 14 is performing a rolling movement on the counter-contact, whereby both these component parts are thoroughly cleaned.

The arrangement'of the miniature relay as shown in Figs. 1A, 1B and 10 represents merely one embodiment given by way of example and wherein some of the components can be replaced by other equivalent constructional elements without departing from the principle of the present invention. Thus, for example, instead of providing hardened and'ground surfaces on the spindle 4 and on the eyelets of the lever 5 for the purpose of pivotally supporting the latter, the presently existing miniature ball bearings can be used for the, same purpose, whereby moreover-the frictional resistances and wear and tear of the components are substantially reduced.

The arrangement of the moveable parts of the miniature relay as shown by way of example in Figs. 1A, 1B and 1C, enabled a miniature relay to be designed which has external dimensions of 30 by 26 by 12 mm., thus occupying a space amounting only to 33 percent of the space required for a normal telephonic relay and moreover achieving a saving of about 70 percent of materials required for the usual telephonic relay, while the operating characteristics or qualities of the above disclosed'miniature relay exceed by far the qualities of a'normal telephonic relay. The general arrangement of the miniature relay according to the present invention is extremely simple so that the possibility of convenient checking in course of" operation and easy adjustment of the relay during assembly are ensured;

We claim:

l. A miniaturerelay for high switching frequencies comprising a frame, a coil mounted on said frame, a pivot pin carried by said frame, a lever pivoted on said pin and carrying an armature for movement between rest and operative positions upon deenergization and energization, respectively, of i said coil, spaced apart pairs of counter-contacts each having two converging, convex contact surfaces, means supporting said counter-contacts from said frame, a movable contact associated with each of'said pairs of counter-contacts for simultaneous engagement with both contact surfaces of a selected one of said pair of counter-contacts, a helical spring for each movable contact, means supporting said helical spring from said frame adjacent one end of the helical spring, a rigid rod-like element extending axially from the other end of said helical spring and carrying the associated movable contact at its free end, said helical spring being disposed to normallyurge the movable contact into engagement with one of the related pair of counter-contacts, a driving member on said lever disposed to be spaced from each rigid rod-like element in said rest'position of the 4. lever and to act against each rigid rod-like element intermediate the ends of the latter during movement of said lever to said operative position for displacing the movable contact toward the other of said pair of counter contacts, the displacement of said driving member by movement of the lever from said rest position to said operative position being greaterthan thatgrequiredgfor efiecting mere engagement of each movable contact with said other counter-contact so that, following engagement of the movable contact with said other counter-contact, further displacement of said driving member causesrocking of each rigid rod-like element about the latter in opposition to the action of the related helical spri'ng'and such rocking produces rolling of the related movable contact on said other counter-contact for ensuring reliable contact therebetween.

2. A miniature relay as'inclaim 1-; wherein said lever has eyelets receiving the ends of said pin for pivotally mounting said lever onsaid pin, and said eyelets andends of said pin have hardened and ground: surfaces for're ducing frictional resistance to pivoting 'of the lever and,

ensuring the long life of the'pivotal mounting of the lever.

33. A miniature relay as in claim 1; wherein said lever has miniature ball bearings mounted on the ends of said pin for pivotally mounting said lever on 'said'irame.

4. A miniature relay as in claim 1; wherein said means supporting the counter-contacts from said frame'ineludes a rigid mounting member for said one counter-contact, and a leaf spring fixed at one end and carrying said: other counter-contact at its other. end to provide a resilient mounting for said other counter-contaot 5. A miniature relay as in'claim 4; further comprising. a rigid backing strip at the side of each leaf springfacing toward said one counter-contact of the related pair of counter-contacts thereby to fixedly --establish the positionof said othercounter-contact when said lever is in its rest position.

6. A miniature relay as in claim 1-; wherein bot-h counter-contacts of each. pair of counter-contacts are rigidly supported'with r'e'spectto'said frame. 7

References Cited in the file of this patent UNITED STATES PATENTS 501,777 Fisher July 18, 1893' 2,296,684 Neuner Sept. 22, 1942 2,547,062 Towner et al. Apr; 3, 1951 2,630,503 Larsen et al. Mar. 3, 1953 2,651,689 Bame Sept. 8, 1953 2,755,346 Fisher July 17, 1956

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