US3056001A - Electric switches - Google Patents

Description

Sept. 25, 1962 L. J. FIGHTER ELECTRIC SWITCHES Filed March 10, 1959 W. M w

IN V EN TOR.

United States Patent ()fi 3,056,001 Patented Sept. 25, 1962 ice 3,056,001 ELECTRIC SWITCHES Ludwig J. Fichter, Chicago, Ill., assignor to Oak Manufacturing Co., a corporation of Delaware Filed Mar. 10, 1959, Ser. No. 798,492 3 Claims. (Cl. 209-67) This invention relates to electric switches and more particularly to switch constructions utilizing small permanent magnets for effecting snap action.

In order that the invention may be fully understood, it will be disclosed in connection with the drawings Wherein FIGURE {1 is a perspective view illustrating one embodiment of the invention.

FIGURES 2 to 5 inclusive are elevations of modifications of structures embodying the invention.

FIGURE 4a is a perspective of a permanent magnet used in the constructions illustrated in FIGURES 4 and 5.

Referring first to FIGURE -1, support is provided upon which the various parts of the switch may be disposed. Support 10 is preferably of non-magnetic material and preferably of insulating material and may be of a suitable plastic moulded piece, either in one part or in a plurality of parts cemented or bolted together. Support 10 has end portion 11 in which are rigidly secured fixed contact arms 12 and 13. Contact arms 12 and 13 are of good electrically conducting metal and extend inwardly through portion 11 to interior 15 of the support. Contact arms 12 and 13 carry at their ends small permanent magnets 16 and 17. Permanent magnets 16 and 17 may be provided with pole pieces if desired. The magnet pole faces function as stationary contacts and cooperate with magnetizable reed part 21. Reed part or armature 21 may be of spring steel or other ferro-magnetic material such as soft iron with body 22 of the reed being of spring material. So long as the reed end is ferro-magnetic, it makes little difference whether body 22 of the reed is ferro-magnetic or not. Reed body 22 has portion 23 moulded in support part 25.

Support 10 has portion 27 extending between ends 11 and 25 of the support. Support portion 27 is provided with a suitable opening in which there is disposed push button 28. Push button 28 has enlarged head 29 terminating in rounded end 30 which is adapted to bear against body portion 22 of the reed. The push button has shoulders 32 which limit the outward movement thereof in support portion 27. Reed 22 is normally biased as by being sprung so that ferro-magnetic end portion 21 bears against magnet 16 functioning as the top contact. From this position, push button 28 may be moved downwardly to move the reed so that armature portion 21 will engage the bottom contact portion.

In order to limit the downward movement of push button 28, support 10 has bottom portion 34 extending between end portions 11 and 25. Bottom portion 34 has massive anvil portion 35 to limit the downward movement of the push button and reed.

By controlling the relative lever arms of the reed cooperating with the push button and with the stationary contacts, various sensitivity characteristics may be obtained.

Referring now to FIGURE 2, a modification is illustrated wherein portion 21' of the reed carries permanent magnet 40. In this modification, stationary contact arms 12 and 13' have end portions 41 and 42 of ferro-magnetic material. It is understood that in the constructions illustrated in FIGURES l and 2, that the pole faces of the permanent magnets will be at the top and bottom of each magnet. Thus, in FIGURE 1, the pole faces for magnet 16 will be at the top and bottom. In the form illustrated in FIGURE 2., the pole faces for magnet 40 will be the top and bottom faces.

In both modifications, the permanent magnets may be riveted or soldered or secured in any desired fashion to the respective supports. It is not necessary that arms 12 and 13 in FIGURE 1 or arms 12' and 13 in FIGURE 2 be of ferro-magnetic material. It is only necessary in FIGURE 2 that ends 41 and 42 of the contact arms be of ferro-magnetic material.

Referring now to FIGURE 3, an additional modification is shown wherein permanent magnets 50 and 5-1 are secured in the top and bottom portions 52 and 53 of the supporting structure. Magnets 50 and 51 are disposed on opposite sides of reed 55 carrying ferro-magnetic button 56. It is understood that ferro-magnetic button 56 ex tends on both sides of the reed so that suitable cooperation with the pole faces of magnets 50 and 51 may be effected.

In the modification of FIGURE 3, the magnets do not carry current. Instead, reed 55 has free end 58 carrying movable contact buttons 59 on opposite sides thereof for cooperation with stationary contacts 60 and 61 carried by contact support arms 62 and 63. In other respects, the modification of FIGURE 3 is similar to FIGURES 1 and 2 in that the reed need not be ferro-magnetic but does carry current.

In all cases, the reed is moulded or anchored in the support and is normally biased upwardly from which position it may be pushed downwardly by a push button. These three modifications are similar in that the push button acts directly on the reed. It is possible, however, to have the push button act on a separate reed arm and transmit the reed deflecting force to the main body of the reed.

Referring now to FIGURE 4 and FIGURE 4a, there is illustrated a modified construction wherein stationary contact arms 62' and 63' extend on opposite sides of end portion 58' of reed 55'. Reed 55' has portion 65 rigidly secured within the end portion of the support structure. Reed 55' carries ferro-magnetic armature 56' which is adapted to operate between pole faces 68 and 69 of U- shaped permanent magnet 70. Preferably, recesses 71 and 72 are provided in the magnet material at the inside corners to prevent short-circuiting the magnet.

Magnet 70 is suitably anchored in support 74 and is so disposed that ferro-magnetic pole piece 56' may move between pole faces 68 and 69. It will be noted that the distance between pole faces 68 and 69 is somewhat larger than the width or thickness of armature 56' so that the armature may move downwardly from the position shown in FIGURE 4. In the position illustrated in FIGURE 4, armature 56' is up against pole face 68. In the downward position of the reed, armature 56' will be clear of pole face 68 and will bear against pole face 69.

Reed 55', like the other reeds, is biased to a normal position, here illustrated as up. It is adapted to be moved downwardly from its up position by means of push button 76- cooperating with leaf 77 punched out from the main body of reed 55. It is understood that leaf 77 is stiff enough so that push button 76 when moved downwardly will force the reed down. In this position, armature 56' will go against pole face 69 of the permanent magnet and contact portion 58' will cooperate with the bottom contact arm.

Leaf 77 may be punched out from the interior portion of the reed in the manner illustrated, for example, in Patent No. 2,140,792, granted December 20, 1938, or the leaf may be a separate reed portion rigidly attached to the body portion of the reed. As with the modifications illustrated in FIGURES l to 3 inclusive, the reed in this form need only be electrically conducting and need not be magnetic.

' 3 Referring now to FIGURE 5, a modification of the structure illustrated in FIGURE 4 is shown. In this modification, armature portion 156 and movable contact portion 158 have their positions on the reed changed. In FIGURE 5, the armature portion 156 is at the free end of the reed rather than in an intermediate part of the reed as in FIGURE 4. Similarly, movable contact portion 158 is at an intermediate portion of the reed rather than at the end as in FIGURE 4. Auxiliary reed 177 extends from the portion on the reed at armature 156 as in FIGURE 4. It is clear that in both FIGURES 4 and 5, the switch operating force exerted by push buttons 76 and 176 must be applied to the armature. As in FIGURE 4, the reed in FIGURE 5 is biased upwardly from which position it may be moved against this bias by downward movement of push button 176.

Due to the fact that permanent magnet 170 in FIGURE 5 cooperates with the free end of the reed, it is possible to turn the permanent magnet so that the end of the reed extends toward the bottom or bight of the U. In FIG- URE 4, the bight of the U is laterally offset from the reed.

What is claimed is:

1. An electrical switch comprising an elongated electrical insulating, non-magnetic block, said block as viewed from the side having the shape of a frame with long top and bottom frame members spaced from each other and maintained by spaced side members to provide an interior region accessible from the side, a pair of fixed contact supporting members carried by one frame side member, said fixed contact supporting members extending through the insulating support to the interior region thereof, the fixed contact supporting portions within the interior region having fixed contacts at the ends facing each other in opposed spaced relation, a flexible reed supported by the other frame side member and having the body portion thereof extending toward the first named frame side member, said reed carrying movable contacts on opposite sides thereof, the contacts forming cooperating contact pairs, at least one of said contacts comprising a permanent magnet with the remaining contacts being of ferro-magnetic material, said reed being normally biased to close against one of the fixed contacts, the contacts having facing planar surfaces for intimate physical contact with each other throughout the area of said surfaces, the cooperating magnet action maintaining said contacts tight with a maximum magnetic force, a push button mounted in one of the long frame members adjacent the remaining side memher, said push button being movable transversely of the reed and having a portion engaging the reed near said other side member, said push button being movable to force said reed away from its normal biased position so that the reed contact engages the other fixed contact and an anvil portion carried by the remaining long frame member and disposed opposite the push button with the reed lying between the two for limiting the movement of said push button whereby said reed is protected from damage due to excessive pressure upon said push button.

2. The construction according to claim 1 wherein said reed carries a permanent magnet, and the fixed contacts comprise armatures of magnetic material.

3. The construction according to claim 1 wherein said fixed contacts are permanent magnets, and the reed carries an armature of magnetic material.

References Cited in the file of this patent UNITED STATES PATENTS 2,480,127 Frerer Aug. 30, 1949 2,518,480 Lilja Aug. 15, 1950 2,529,652 Dicke Nov. 14, 1950 2,665,344 Zozulin Jan. 5, 1954 2,688,063 Gomersall Aug. 31, 1954 2,782,278 Peters Feb. 19, 1957 FOREIGN PATENTS 98,871 Austria Dec. 27, 1924 163,579 Australia June 24, 1955

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