US2922857A - Contact making device - Google Patents

Description

Jan. 26? 1960 R. L. PEEK, JR 2,922,857

CONTACT MAKING DEVICE Filed Sept. 24, 1957 F/G. Z

/N VEN TOR R. L. PEE/r, JR.

A TTORNE' V 1United =States Patent() 2,922,857 CONTACT MAKING DEVICE Application September 24, 1957, Serial No. 685,916 5 Claims. (Cl. 200-87) This invention relates to contact making devices, and more particularly to such devices of the sealed reed type having fast operating speed. I `As, new switching systems are developed having a large number of electronic components enabling them to operate at faster speeds than priorly attainable, theslowness of operation of the electromechanical switches or relays with which these systems must cooperate becomes a major problem. Many present switching systemsv utilize all metallic paths for the transmission of voice currents because of the reliability of the all metallic path, as opposed to a path including electron discharge tubes. However, the present slow operating relays which comprise the switches of that metallic path render nugatory the possible high speeds of operation attainable by the electronic control circuits for the relays.

While it is generally' realized that faster operating speeds can be obtained by reducing the spacing between the contact making members, there has been difficulty in the past in manufacturing sealed reed type relays with a high degree of gap spacing accuracy. yAnd because of this inability to insure a highly accurate spacing of the contact making members, the latter necessarily cannot be brought as close together as would be desirable. It is an object of this invention to achieve a more accurate, as well as closer, spacing of the contact making members of a sealed reed type relay.

It is another object of this invention to increase the operating speed of contact making devices.

These and other objects are attained in accordance with this invention wherein a pair of spaced, parallel, supporting wires under tension are each provided with contact making members comprised of magnetic material. A longitudinally spaced pair of said contact members are mounted on one of said supporting wires,'and single contact member is mounted on the other so that when said contact members are brought together under a magnetic force the single contact member bridges, and contacts, said pair of contact members. The contact members are disposed within a tubular, non-magnetic envelope with the pair of ,supporting wires securely mounted at each of the ends thereof. Becausethe pair ICE duce such openings. Finally, this parallel contact arrangement minimizes contact sticking. If one contact should stick, a force is exerted, at the opposite end of the single contact member, which sets up a prying action at the point of contact causing said contact to break.

These and other features of this invention may be more fully understood by reference to the following detailed description and accompanying drawing, in which:

Fig. 1 is a side view of a sealed reed type relay illustrative of one specific embodiment of this invention, a portion of the enclosing envelope being broken away to reveal the internal members more clearly and the encompassing magnetic coil being shown in section;

Fig. 2 is a similar view showing a second embodiment of this invention;

Fig. 3 is a similar view of another embodiment of the invention in which a permanent magnet, back contact member is added; and

Fig. 4 is a slightly enlarged view taken on the line 4-4 of Fig. 3.

vReferring now to Fig. l, `in the specific illustrative embodiment there depicted a pair of parallel, supporting members 1'1 and 12 formed of wire are positioned in a tubular, hermetically sealed, glass envelope 13. The wires are spaced a predetermined distance apart and are sealed under tension in each of the ends of the glass envelope 13. A longitudinally spaced pair of tubular contact members 14 and 15 are mounted on wire 12, and single, tubular, contact member 16 is mounted on wire 11. The contact member 16 is symmetrically disposed ywith respect to the opposed Contact members 14 and 15 so that when said contact members are moved toward each other, under the influence of a magnetic force, the member 16 makes contact with both members 14 and 15. The tubular contact members have an inside diameter slightly larger than the diameter of wires 11 and 12 so that they may be readily threaded thereon, and when properly positioned along the lengths of wire, the contact members are secured in place by a simple crimping or squeezing operation. The wires 11 and 12 are preferably formed of non-magnetic material, while the contact members can be of any soft magnetic material. Choice of material for wires 11 and 12 varies with the method of supporting and sealing the switch. For a switch hermetically sealed in glass the material must retain its tension during the heating involved in sealing the glass-tungsten and molybdenum are mate# rials that have been found satisfactory for such use. The tubular magnetic contact members 14, 15 and 16 are plated with a thin layer of a non-magnetic material A (e.g.,v silver) to provide a small non-magnetic gap beof wires are mounted in position under tension, .the

distance between the midpoints thereof, along with the distance between the opposed contact members, can be accurately set to any given amount.

A further feature of the invention lies in the parallel contact arrangement employed, The single contact member mounted on one of the wires contacts both the contact members mounted on i the other, thusl providing parallel, electrical connectionsbetween the wires.` This provides contact on two separate areas, thus increasing contact reliability as dirt or film cannot prevent electrical closure unless present on both areas of contact. at once. It also reduces contact chatter resulting from small transient separations due to vibration, particularly Ithat resulting fronrimpaet in operation, as there must be Simultaneous separation at both contact areas to protween the members in contact to reduce any magnetic attraction due to residual magnetism when the energiz ing coil 17 is deenergized, thus facilitating release ofthe switch. This non-magnetic layer may itself be a suitable material for electrical contact, or be plated'with a second layer of such material. rIhus, if an inert` gas is used to ill the hermetically sealed tube, a silver plating may alone be used, or if the tube is sealed in air the silver coating may be covered with a thin plating of 'gold`to assure satisfactory electrical contact. Y

An energizing coil 117 encompasses the envelope 13. 'On energization of this coil a magnetic eld is provided which causesthe contact members to move towardeach other to close the gaps 18 and 19, and thus provide par# allel electrical connections between the wires 11 and l12. Upon removal of this eld the tension stress in the wires restores the contact members to their, original positions. Inasmuch as the tubular contact members 14.and15. are relatively inflexible and they extend along a` major port 5 tion of the enclosed length of wire 12, it willj beobvious that the lateral movement of these contact members will be less than that of contact member 16. Y

As has been noted, the wire supporting members 11l the parallel supporting members 25 and 26, formed of wire, are mounted in glass envelope 27 under tension. As in Fig. 1, the tubular contact members 28 and 29 are mounted on wire 26, and a single, tubular contact member 30 is mounted on wire 25 so as to make contact ,withboth the members 28 and 29 when said contact members are moved towardeach other under the indistance between the opposed, contact, members, can, be

set. with the 'samedegree of accuracy that the -wireends are displaced. "illus,V byknowing the wire and contact member diameters, the setting ofthe gapV and the measurement thereof can be effectively carried outV at the free ends of the wires. It has .been found that this. arrangement affords a greater degree of control over. gap setting than existing arrangements wherein reed wires enter respective ends o f a tubular envelope and the gap setting is carried out by angularly offsetting the. wires' in opposite directions. Fabrication of the instant device has shown that the gap spacing can be set with an accuracy of ygreater than' 112 mil. it` follows, that with increased accuracy in gap setting, it is possible to set the opposed contact members much closer together.

With the gap spacing set the selected amount,V the ends of the glass tube are sealed by the application of heat. Aithough this may cause some tendency toward relaxation of the tension, the wires will remainsubject to sufficient tension to insuresatisfactory operation.

1n addition to faster operatingspeed, less chatter is experienced as the gap distance is shortened. Chatter is the result of the relay contacts coming together at suficiently high velocities to cause a rebound upon impact. By decreasing the distance between the Contact making members the velocity reached by the members just prior to impact is accordingly lowered with the result that rebounds and accompanying chatter are less likely to occur. In addition, as previously explained, chatter openings can onlyoccur in this parallel contact arrangement when member 16 rebounds simultaneously from both members 14 and 15 and small differences in ther times at which these rebounds occur reduce the time in which the contact is open.

When the switch gaps 18 and 19 are closed the wires 1\1 and 12 are interconnected through parallel contact paths.v Besides providing dual contact areas, which give added insurance against dirt, iilms, and the like, and which decrease contact chatter, this arrangement tends to minimize the problem of contact sticking. Assuming for the moment that the contacts of switch gap 18 should stick, the tubular contact member 16 would tend to assume an angular position with respect to contact member 14, and thus a prying action would be set up at the point of contact causing said contact to break. More specifically, if the contacts of switch gap 18 should stick, the tensioned wire 11 would set up a force at the point 21 which, acting through the lever arm (contact memberf16), would force or pry apart the members 16 and 1 4. This same type action would of of course take place should the contacts of gap 19 be the ones to stick.

In the embodiment of Fig. 2, the parallel supporting members 22 and 23 are formed of non-magneticY flat tapes and the contact members 24, comprised of ilat strips of magnetic material, are mounted thereon by spot welding or the like. In all other respects this modification is equivalent to that shown in Fig. V1. The Fig. 2 embodiment does tend to lend itself more readily to mass production techniques, and thus from this standpoint alone it may be somewhat more desirable than the-embodiment of Fig. 1.

Y Turning to the moditication shown in Figs. 3 and 4,

fluence of amagnetic force.` In addition, supporting member 31 isimounted' within envelope 27 under tension and is spaced from and parallel to the supportingmen. bers and 26. Y Supporting member 31 is formedv of a wire of suiiicient thickness as to reduce any lateral movement thereof to -anegligible amount. l

A tubular back AContact member 32 is mounted on wire 31, in the predescribedmanner, andV is coextensive with contact member 30. The contact member 32 is permanently magnetized so as to normally hold member in contact therewith and out of contact with members 28 and 29. yWhen the encompassing coil 35 is energized in the sensethat creates a magnetic tieldin the same di rection as thatkwithin the permanent magnet 32?,Y this vfield opposes the previously existing return fieldv of the permanent magnet in member 30, diverting the permanent` magnet iield to` an air return path, and reducing or tending to nullify the field between 30 and 32. This newY coil held will follow a path through members 28, 30, and 29, and will movefmember 30 into contact with members 278v and 29. Upon deenergization, the Contact l member 30 is returnedV to its normal position under the.

influence of the iield ofthe permanent magnet. If desired the relay of Figs. 3 and 4 can provide a transfer operation. That is, the wire 31 may also be connected to an external circuit, arid upon energization of thecoil 35, electrical contact with wire 25 is transferred from wire 31 to wire 26.

This invention has been described in terms of certain specific embodiments, and since modications and equiv- Y alents thereof may be apparent to those skilled in the art,

this description is intended to 4be illustrative of and not necessarily to constitute a limitation upon the scope of the invention. l

What is claimed is: 1. A contactmaking device comprising a non-magnetic envelope, a pair of parallel spaced ilexible supporting members of non-magnetic material mounted within said envelope under tension, a pair of longitudinally spaced contact members of magnetic material mounted on one of said supporting members, a'single contact member ofY magnetic material mounted on the other of said supporting members, said single contact member being symmetrically disposed with respect to the opposed pair of, contact members soY as to make contact with-both of said opposed pair when said contact members are moved to-` ward each other.y

2. A contact making device comprising a hermetically sealed non-magnetic tubular envelope, a pair of parallel spacedir supporting wires of non-magnetic material mounted within said envelope under tension, said wiresk being sealed in the ends of said tubular envelope, a pair of longitudinally spaced tubular contact members of mag-A netic material mounted on one of said supporting wires, and a single tubular contact member of magnetic material mounted on the other of said supporting'wires, said single contact member being symmetrically disposed with respect to the opposed pair .of contact members so as to make contact with both of said opposed pair when said contact members are moved toward each other.

3.- A contactmaking device comprising a hermetieall'y sealed non-magnetic tubular envelope, a pair of parallel of non-magnetic *materiali mounted within said envelope under tension, said tapes being sealedrin the ends of said tubular envelope, av pair of longitudinally spaced contactmembers of magnetic material mounted on one of said supporting tapes, a single contact member of magnetic material mounted on the other of said supporting tapes, said contact members having ilat contact making surfaces, and said single contact member being symmetrically disposed with respect to the opposed pair of contact members so as to make contact with both of said opposed pair when said contact members are moved toward each other.

4. A Contact making device comprising a hermetic-ally sealed non-magnetic envelope, a pair of parallel spaced flexible supporting members of non-magnetic material mounted Within said envelope under tension, a pair of longitudinally spaced contact members of magnetic material mounted on one of said supporting members, a single contact member of magnetic material mounted on the other of said supporting members, said single contact member being symmetrically disposed with respect to the opposed pair of contact members so as to make contact with both of said opposed pair when said contact members are moved toward each other, a third parallel spaced supporting member of non-magnetic material mounted within said envelope under tension, and a permanent magnet mounted on said third supporting member for holding said single contact member in contact therewith and out of contact with said pair of contact members in the absence o any external magnetic influences.

5. A contact making device comprising a non-magnetizable envelope, a pair of spaced-apart elongated ilexible members of non-magnetizable material, each of the ilexible members being arranged within the envelope and longitudinally tensioned, magnetizable first contact means mounted on one of the iiexible members, magnetizable second contact means mounted on the other iiexible member, the rst and second contact means being normally separated from each other, and magnetic means, outside of the envelope, operable for causing the first and second contact means to move into mutual contact.

References Cited in the le of this patent UNITED STATES PATENTS 986,039 Bachelet Mar. 7, 1911 1,984,505 Walker Dec. 18, 1934 2,076,162 Ruth Apr. 6, 1937 2,381,309 Powell Aug. 7, 1945 2,706,756 Brewer Apr. 19, 1955 2,727,114 Kesselring Dec. 13, 1955

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