US 3704514 A
Two magnetizable contact springs are hermetically sealed in a tube to be controlled by magnetic force from the outside. The two contact springs are made from flat strip material by a single stamping operation which produces a substantially rectangular frame structure which is open at one of the short sides where the contact faces are to be located. The frame is joined with, and sealed in, the tube so that the two leg portions of the frame structure extend to the outside of the tube where the frame structure is ultimately cut away to leave two separate terminals. A normally open contact is formed by bending one of the two legs, at least at its top portion, so that it forms a contact face opposite the contact face of the other leg.
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United States Patent Fuchs et al.
 SEALED ARMATURE CONTACT RELAY MAKING PROCESS I v  Inventors: Walter Fuchs; Horst Esche, both of Berlin, Germany  Assignee: Deutsche Telephonwerk und Kabelindustrie Aktiengesellschatt, Berlin, Germany  Filed: Dec. 30, 1969 [211 Appl. No.: 888,125
A Related U.S. Application Data  Continuation of Ser. No. 641,570, May 26, 1967,
 Foreign Application Priority Data June 4, 1966 Germany ..D 50248  U.S. Cl. ..29/622, 113/119, 335/151, 200/166 C, 200/166 B, 29/602  lint. Cl. ..H01h 69/02  Field of Search ..29/622; 335/151-154; 113/119; 200/166 C, 166 B  References Cited UNITED STATES PATENTS 3,128,355 4/1964 Fuller ..29/622 AK, 2r
v FOREIGN PATENTS OR APPLICATIONS 1,184,015 12/1964 Germany ..29/622  ABSTRACT Two magnetizable contact springs are hermetically sealed in a tube to be controlled by magnetic force from the outside. The two contact springs are made from flat strip material by a single stamping operation which produces a substantially rectangular frame structure which is open at one of the short sides where the contact faces are to be located. The frame is joined with, and sealed in, the tube so that the two leg portions of the frame structure extend to the outside of the tube where the frame structure is ultimately cut away to leave two separate terminals. A normally open contact is formed by bending one of the two legs, at least at its top portion, so that it forms a contact face opposite the contact face of the other leg.
4 Claims, 4 Drawing Figures PATENTEDUEC 5 I972 FIG.4
SEALED ARMATURE CONTACT RELAY MAKING a PROCESS This application is a continuation of Ser. No. 641,570, filed May 26, 1967, now abandoned.
Our invention relates to sealed tubular contact devices which are controllable from the outside by applying an electromagnetic or permanently magnetic field for actuating a normally open or normally closed contact in the tube.
There are known sealed armature contact devices which are fused into a tube of glass or other insulating material having a small diameter and whose contactforming parts consist of magnetizable material in the form of a wire or strip, such as a wire beaten flat. The interior of the protective tube is evacuated or filled with protective gas. The ends of the contact-forming parts extend out of the protective tube and serve as externally accessible terminals. The other ends of the parts located within the protective tube are slightly spaced from each other.
According to the method described in the German Pat. 1,060,494, an armature contact sealed in a protective tube is produced from a wire of given length by bending its contact end to an elongated loop. The free ends of the loop are flattened and overlap each other so as to serve as contacts which engage each other when a magnetic field is applied.
The German Pat. 1,170,072 discloses a sealed tubular armature contact device made of wire whose round cross section is flattened at the contact locations, and these locations are embossed to enlarge the contact face and reduce the thickness of the wire material. Since the enlargement of-the contact faces does not involve an increase in the mass of the movable parts, the magnetic saturation values remain unchanged and one obtains a larger coupling area for the controlling magnetic field arranged outside of the protective tube, as compared with the flattened but unembossed contact wires. The resulting stiffness of the magnetizable contact legs, accompanied by a reduction in thickness, af-
fords shortening the contact legs for a given magnetic attraction, or reducing the attractive force required for the switching operation. 1
Another device, shown in the German Pat. 1,090,765, likewise attempts to reduce the space requirements of magnetically controlled contacts and thereby also reducing the over-all dimensions of a relay equipped with such contacts. For this purpose the mutually opposite front faces of two flat contact springs are designed to enter into contact with each other, and at least one of these springs is adapted to move in its plane, under the effect of the magnetic field, in such a manner that the front faces will engage each other.
All of the sealed tubular contact devices for magnetic operation heretofore available leave much to be desired. Thus, the elastic stresses imposed upon the cross section of each contact member is concentrated in a small region where the flat profile merges with the round profile of the wire material. The remaining portion of the contact member, hardly stressed elastically, greatly reduces by its high inertia the natural frequency of the member, thus increasing the kinetic energy effective when the contact member impinges upon the counter contact. As a result, intensive bouncing is encountered. Such deficiencies are supposed to be minimized by applying meander-like variations to the cross section of the contact springs. Of disadvantage further is the bilateral embossing process required for some of the other types of contact devices, as well as the requirement that the geometric axes of the contact springs be offset in parallel relation to each other in the protective tube in order to have the contact engagement take place perpendicularly to the direction of spring motion. This aggravates fusing the contact-making parts together with the glass or similar material of which the protective tube is made.
The German Pat. 1,117,761 describes a sealed tubular and magnetically actuable contact device whose contacts proper are constituted by the free ends of two contact springs which are sealed in the protective tube and are machined from a wire of round cross section by a unilateral pressing or embossing operation. In this device the contact-making faces widen gradually, and the thickness of the springs gradually decreases from the contact-making side toward the terminals, so that the elastic deformation of the contact springs, occurring perpendicularly to the contact faces, will impose an approximately uniform elastic stress upon the entire length of the springs.
It is an object of our invention to devise a sealed tubular contact device with magnetically controllable contact members which avoids the shortcomings of the devices of this general type heretofore-available and which also affords producing such sealed devices by a method that is simpler to apply and that also reduces the cost of materials and labor required for the manufacture of the device.
Another, more specific object of the invention is to provide a novel contact device and a method of its manufacture that secure a minimum danger of bouncing or arcing at the contacts even if the device is given reduced dimensions in comparison with known devices of the same voltage or current rating.
Another, conjoint object is to secure in a simple manner a distribution of the elastic stress, caused by magnetic actuation, over the entire cross section and substantially the entire length of each contact member.
To achieve these objects, and in accordance with a feature of our invention, we produce the two cooperating contact members of a sealedtubular and magnetically actuable contact device from a flat magnetizable sheet or strip material, preferably in a single step of stamping or other suitable shaping operation, by first shaping a generally frame-shaped rectangular structure that is open at one of the short sides where ultimately the contact faces are to be constituted. We then bend only one leg portion of such an open frame structure so as'to place the contact-forming end of that leg portion into cooperative opposition to the adjacent end of the other contact member. Subsequently we hermetically seal this structure into the protective tube but let the closed narrow side of the frame structure remain outside one of the ends of the tube, while the contactforrning localities are located inside the tube, preferably near the other end thereof.
Relative to this and other features of out invention, reference should be had to the claims annexed hereto, as well as to the accompanying drawings in which embodiments of sealed tubular contact devices according to the invention are illustrated by way of example.
FIG. 1 shows, partially in section, a lateral view of one form of a sealed tubular contact device.
FIG. 2 illustrates, also in partial section, the same device turned 90 about its longitudinal axis.
FIG. 3 is a plan view of the stamping cut of which the contact members proper are made; and
FIG. 4 is a plan view of another embodiment of a stamping suitable for producing the contact members of tubular devices according to the invention.
The sealed tubular contact device according to FIGS. 1 and 2 comprises a preferably flat protective tube 1 of glass or other non-metallic and non-magnetic material. The contact system 2 in the embodiment of FIGS. 1 and 2 constitutes a normally open relay con tact. The system is made of a single frame-shaped blank stamped out of magnetic sheet or strip material to the rectangular shape shown in FIG. 3 or FIG. 4. As will be described, the contact-system 2 results from such a blank by applying a single bending operation. The contact system 2 is fused into the protective tube 1 in such a position that the contact-forming ends of the open frame structure are located inside the tube, preferably in the vicinity of one tube end. The other narrow side of the frame structure, remaining closed as shown in FIGS. 3 and 4, protrudes out of the fused tube 1. Ultimately the closed end of the frame structure is cutaway along the line 11 in FIG. 1. The two shanks or legs which then remain of the original frame structure thus constitute electric terminals 4 and 5 which form a glassto-metal seal with the protective tube and are accessible from the outside. The interior of the protective tube 1 is evacuated or filled with inert or noble gas such as argon.
Referring to the stamped or cut blanks of flat magnetizable and elastic material shown in FIGS. 3 and 4, it will be seen that each of them essentially constitutes an elongated rectangular frame which is open at one of its narrow sides. In both embodiments, the electric contact localities 21, 22 (FIG. 3) or 31, 32 (FIG. 4) are adjacent to the open ends of the frame structure. Preferably the contact faces are coated with silver or other noble metal, at least at the side facing the opposite contact and entering into engagement therewith when the contact is closed. 1
In the embodiment of FIG. 3, the open frame structure is composed of a U-shaped portion whose respective legs 24 and 25 are unequal in length. The longer leg 25 has a T-shaped top portion whose trunk is parallel to the bottom portion 23 of the U-shape. The bottom portion 23 may have the same width as the respective contact faces 21 and 22. The legs 24 and 25 of unequal length have different configurations in the longitudinal direction of the legs. That 'is, according to FIG. 3 the two legs are provided with lateral recesses which are longitudinally offset from each other. For example, the recess 31 of leg 24 is displaced relative to the recess 311 of leg 25 by an amount designated by 3. As a result, each of the two spring legs 24, 25 has a natural frequency differing from any even multiple of the other. This is particularly advantageous for preventing contact bouncing when the normally open contact is being actuated.
For converting the blank according to FIG. 3 to a contact system as shown in FIGS. 1 and 2, the T-shaped portion on top of leg 25 must be bent approximately 180 in the vicinity of the contact locality 21 and along the dot-and-dash line 27. The bending deformation, of course, must be permanent. Care must be taken that the two contact faces 21 and 22 will overlap a sufficient extent and that the spacing shown at 6 in FIG. 2 remains preserved between the legs 24 and 25, as well as between the appertaining contact faces 21 and 22. When a magnetic field is applied, the elastic legs or shanks 24 and 25 attract each other so that the contact faces 21 and 22 are firmly pressed against each other. When thereafter the magnetic field is removed, the contact members return to their respective starting positions, thus opening the contact between faces 21 and 22. Since the working gap 6 can be correctly determined by the manufacturing operation, such as with the aid of a jig, no further adjustment, as a rule, is needed for properly setting the normally open contact.
The open frame structure in the embodiment according to FIG. 4 also comprises a U-shaped portion whose legs or shanks 43 and 44 are unequal in length. The longer leg 44 has a T-shaped top portion whose trunk is parallel to the bottom portion 45 of the frame structure and which forms a contact face at 41. In this embodiment, however, the base of the U-shaped bottom portion is longer than the T-shaped portion; and the leg 43 is to be bent about along the dot-and-dash line 46 which extends parallel to the legs and through the bottom portion 45 of the U-shape. Due to such bending, the contact faces 41 and 42 become located opposite each other and will overlap while preserving the desired contact space between each other. For securing the spacing necessary for a normally open contact, the bending edge 46 must be spaced from the leg 43 an amount substantially equal to the one designated by 6 in FIG. 2. That is, after bending the leg 43, it will extend parallel to the plane of the base portion 45 but spaced therefrom a distance corresponding to the one denoted by 6. a
When producing the contact system 2 it is preferable to perform the stamping according to FIG. 3 or FIG. 4 in such a manner that upon completion of the bending operation the burr side of the open frame structure will not be located in the direction of the contact-making faces 21, 22 or 41, 42. That is, any burrs should face outwardly so that they are harmless. This avoids the necessity of deburring so that the manufacturing process is reduced to a minimum of steps.
To those skilled in the art it will be obvious from a study of this disclosure that our invention is amenable v to various modifications with respect to type, size and configuration of the contacts or other components, and hence may be given embodiments other than particularly illustrated and described herein, without departing from the essential features of our invention and within the scope of the claims annexed hereto.
1. In a method of producing a sealed contact device which comprises stamping from a flat strip of magnetizable elastic material having opposite planar faces a substantially rectangular frame structure formed of a substantially U-shaped and a substantially T-shaped portion, said U-shaped portion including a short leg and a pair of opposite long legsconnected to said short leg, one of said long legs being longer than the other, and said T-shaped portion including a trunk part connected to said longer long leg and extending substantially parallel to said short leg, said T-shaped portion being formed with an end portion spaced from the shorter long leg and extending in the same direction and laterally adjacent an end portion of the shorter long leg, bending one of said U-shaped and T-shaped portions back upon itself to a permanent position in which the end portion of said T-shaped portion and the end portion of said shorter long leg overlap one another in mutually spaced relationship and have mutually opposing contact surfaces, respectively, that are from the same planar face of the flat strip and form a normally open contact with each other, inserting part of the structure including the normally open contact into an elongated protective tube through an open end of the latter, so that the remainder of the structure including said short leg is located outside the open end of the tube, and sealing the open end of the tube.
2. The method according to claim 1, wherein said bending is substantially limited to the end portion of said T-shaped portion and is given an angular amount of approximately the bending being done about a line parallel to the longitudinal direction of said frame structure.
3. The method according to claim 1, which comprises bending said shorter long leg about 180 about a line extending parallel to the longitudinal direction of the frame structure and through said short leg of the frame structure.
4. The method according to claim 1, which comprises cutting the short leg away from the frame structure for separating the outside ends of said long legs,
respectively, from one another to thereby form respective terminals.
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