US2719891A - Magnetic vibratory switch - Google Patents

Description

Oct. 4, 1955 S. F. JAMES ETAL MAGNETIC VIBRATORY SWITCH Filed June 26, 1952 4.6! Source INVENTORI STEPHEN F. JAMES EST/152D. AMES I ATT'YS United tates Patent MAGNETIC VIBRATORY SWITCH Stephen F. James and Esther D. James, (Jhicago, Ill. Application June 26, 1952, Serial No. 295,664 7 Claims. (Cl. 200-90) This invention relates to vibratory electrical switches and is particularly directed to improving the operation and simplifying the construction thereof.

Vibratory switches are extensively employed for radar control and auto-radio control. As usually constructed, they are subject to bouncing of the reed arms which disturbs the synchronism of the controlled circuits.

This invention is a specific improvement on the construction shown in our Patent No. 2,536,748 of January 2, 1951, and our co-pending application for patent on Vibrators, Serial No. 271,214, filed February 12, 1952, now Pat. No. 2,659,784.

The main objects of this invention are to provide an improved construction for vibratory electrical switches, such as are used in radio circuits, which is of simple structure and capable of long life without attention and of being made very small in size; to provide an improved reed structure for such switches; to provide an improved form of double pole double throw radar switch; and to provide an improved frame structure for facilitating the mass production of such devices.

A specific embodiment of this invention is shown in the accompanying drawings, which show the same on an enlarged scale and in which:

Figure 1 is a side elevation, partly in section, of a magnetic switch operating device constructed according to this invention. Full lines show a simple arrangement of alternately acting pairs of current interrupting switch contacts suitable for use as a chopper. Broken lines show additional contacts for double pole double throw arrangement suitable for use as an alternating current synchronous antenna switch.

Fig. 2 is an elevation of the same as viewed from the right side of Fig. l, but omitting the extra upper externally mounted stationary terminals.

Fig. 3 is a plan of the same viewed from the bottom of Fig. l, the line 22 indicating the side from which the elevation of the Fig. 2 is viewed.

Fig. 4 is a section taken on the irregular line 4-4 of Fig. 1.

Fig. 5 is a detail showing the shape of the plate which provides the reed or vibratory tongue that controls the action of the movable switch arms.

Fig. 6 is a top view of the frame as seen from the line 66 of Fig. 2.

Full lines in Figure 1 of the drawings show the switches 10 and 11 in simple illustrative form wherein each comprises a single pair of contact members 10.1 and 10.2 or 11.1 and 11.2 at respectively opposite sides of the reed 12, but it will be understood that these can be readily modified to work as other forms suitable for specific circuit purposes where the make and break is to be of vibratory nature.

The operating mechanism of the switch comprises a resilient sheet metal tongue or reed 12 that has one end fixed on the supporting frame 13, and carries at its free end an elongated armature arm 14 that extends axially through a hollow center of a magnetizing coil 15 which ice may consist of the usual helical solenoid winding with its terminals 16 connected to an alternating current source. The armature 14 extends slightly beyond the upper end of the coil 15, as shown in Figs. 1 and 2. Immediately above and clear of the upper end of the armature 14, are a pair of magnet pole-pieces of fixed but opposite polarity as indicated in Fig. 1. These pole-pieces are magnetized by permanent magnet 18.

In the form shown, the pole-pieces 17 are of L-shape comprising vertical legs 19 riveted or otherwise secured to the top plate 20 of the frame 13. As will be seen from Fig. l, the legs 19 are in magnetic contact with the ends of the magnet 18, and the portions 17 extend below the magnet so as to clamp it to the plate 20 with an interposed non-magnetic spacer 21, which assures a concentration of magnetic flux across the nearly closed gap between the opposed ends of the pole-pieces 17.

The frame 13 is generally of rectangular form so that it may be conveniently cut from strip stock by a stamping operation, and comprises in addition to the top plate 20, side bars 22 and a bottom or base plate portion 23. In finished form the side bars 22 and base portion 23 lie in a single plane and the side bars 22 are bent at right angles to this plane adjacent their upper ends so that the plate 20, which is initially blanked out in the same plane with the side bars 22 and base bar 23, will stand at right angles to the side bars 22.

The magnetizing coil 15 has insulating end plates 24 which have fastened on the outside thereof a layer of copper foil 25. This provides R. F. shielding and means whereby the coil ends can be soldered to lugs 26 on the side bars 22, which lugs are suitably located to fix the position of the coil lengthwise of the armature. The end plates are shaped to fit between the side bars 22 and have their side edges offset to provide shoulders 26.1 that abut against side bars 22 to center the coil with the armature 14 in an axial position. The coil 15 is hollow and its axial core space 27 is of suflicient diameter to accommodate the desired vibratory motion of the armature 14 without interference.

In the form shown, the armature 14 is made up of two similar bars of magnetically permeable material, such as soft iron, which are of T-shaped form with elongated shanks and with crossheads 28 at their lower ends that are clamped to opposite sides of the reed plate 12 by rivets at 29. The shanks of the bars that form the armature 14, are preferably welded together at one or more points above the crossheads 28.

The bar 23, which forms the base member of the frame 13, is extended downward in the form of a rectangular panel 30 to which the reed plate 12 is fastened by a bolt 31. The reed plate 12 has an aperture 32 for the bolt 31, as well as apertures 29 for the armatures rivets, and has an intermediate aperture 33 elongated horizontally to give definite transverse sectional area to the tongue portions 34, which area is varied by increasing or decreasing the size of the aperture 33 to regulate the flexibility of the tongue as a reed so that its period of vibration approximates the frequency of the alternating current source. The higher the frequency, the less flexible should be the reed.

The switches 10 and 11 comprise stationary resilient contact arms 10.1 and 11.1 and movable resilient contact arms 10.2 and 11.2 which extend at right angles to the plane of the reed. The switch arms 10.2 and 11.2 have upstanding base flanges 35 that are fastened to the heads of the armature by the same rivets 29 that attach the armature to the reed plate 12. The contact arms 10.1 and 11.1 have depending base flanges 36 that have edge contours identical with that of the reed plate 12 below the aperture 33, and have perforations for the bolt 31 but of somewhat larger diameter than the perforation 32 of the reed plate so as to allow room for insulating the flanges 35 from said bolt. The flanges 36 of the contact members 10.1 and 11.1 have terminal lugs 37 to which circuit conductors may be soldered, and a filler shim 38 which is in electrical contact with the reed plate 12, has a terminal lug 39 for attaching the conductor that is to be connected to the switch arms 10.2 and 11.2. The switch contacts are normally open when the reed is at the middle of its vibratory amplitude.

When this unit is used as a radar switch, the additional stationary contacts 10.3 and 11.3, shown in broken lines in Fig. l, are employed for double pole double throw switch arrangement. In such case, the switch arms 10.3 and 11.3 are supported independently and are connected to the antenna. The stationary contacts 1G1 and 11.1 are separately connected to the ground and the movable contacts 10.2 and 11.2 are insulated from the reed and connected to the receiver.

In the case of choppers, the switch contacts are normally closed in static position so as to provide makebefore-break operation.

For convenience of assembly for mass production, the parts 12, 30, 36 and 38, and the insulation members that separate these parts, have identical edge contours at the sides and bottom thereof, and each is provided with a pair of notches 40 of identical semicircular form for engagement with jig members that guide them in place as they are assembled. In order to permit the substitution of an electromagnet for the permanent magnet where this is desirable, the frame may have a hole 41 centrally located in the top plate 20. The frame stamping, thus formed with a central aperture 41 for attachment of an electromagnet core and a pair of apertures equally spaced at opposite ends of the top plate 20 for the legs of the permanent magnet terminals 17, is versatile in its availability without change for use in mass production of any of the usual types of vibrators. By inserting a standard vibrator reed into the stack assembly, the unit becomes a midget auto radio vibrator. It is desirable, but not necessary, to use steel in stamping the frame for this application. This frame structure locates the plane of reed substantially in the plane of the side bars 22 of the frame and since the contact arms extend at right angles to this plane close to the aperture in the reed arm, the structure may be of minimum height without restriction on the length of these contact arms to obtain maximum closure time, while permitting the use of maximum size and length of the driving coil.

In operation, the polarity of the upper end of the armature 14 is reversed by the alternating current in the coil 15 at the same frequency as that of the source current and accordingly is alternately attracted and repelled by the poles of the permanent magnet 18 so as to vibrate at right angles to the plane of the reed.

Although but one specific embodiment of this invention is herein shown and described, it will be understood that numerous details of the construction shown may be altered or omitted Without departing from the spirit of the invention as defined by the following claims.

We claim:

1. In a vibrator, a reed, an armature on the free end thereof, a frame formed from a single sheet of metal and comprising a base plate to which said reed is attached and side bars located in a common plane with said reed and base plate, and a top plate located in a plane at right angles to said reed and to the plane of said side bars, a permanent magnet attached to said top plate and having its opposite poles adjacent to said armature in the plane of vibration of said reed, a driving coil surrounding said armature and secured to said side bars, a pair of movable contact arms attached to said reed below said driving coil and extending in opposite directions at right angles thereto in its plane of vibration, a pair of contact arms attached to said frame and extending substantially parallel with said movable contact arms, and coacting contact elements on the free ends of said contact arms.

2. In a vibrator having a vibratory reed and electromagnetic means for vibrating it, a supporting frame therefor, comprising a unitary sheet of metal shaped to provide a base plate, a pair of spaced parallel side bars located substantially in a common plane with said reed and base plate, said side bars being attached at their one end to opposite sides of said base plate, and a top plate attached to the other ends of said side bars and lying in a plane at right angles to said first-named plane and being disposed between said side bars symmetrically with respect to said first-named plane.

3. In a vibrator having a vibratory reed and electromagnetic means for vibrating it, a supporting frame therefor comprising a unitary sheet of metal shaped to provide base plate, a top plate, and a pair of spaced parallel side bars located substantially in a common plane with said reed and base plate, said side bars being connected at their one end to respectively opposite sides of said base plate and at their other end to respectively opposite sides of said top plate, said side bars being bent adjacent said top plate to dispose said top plate at right angles to the plane of said base plate, said top plate being shaped to extend in similar shape for equal distances toward opposite sides away from said plane.

4. In a vibrator havin a vibratory reed and electromagnetic means for vibrating it, a supporting frame therefor comprising a unitary sheet of metal shaped to provide a base plate, a pair of spaced parallel side bars located substantially in a common plane with said reed and base plate, said side bars being attached at their one end to opposite sides of said base plate, a top plate attached to the other ends of said side bars and lying in a plane at right angles to said first-named plane and being disposed symmetrically with respect to said base plate, said reed eing attached to said base plate, said electromagnetic means being adjacent said top plate, a pair of movable contact arms attached to said reed and extending in opposite directions at right angles to its plane of vibration, and stationary contact members coacting with said movable contact arms.

5. In a vibrator having a vibratory reed and electromagnetic means for vibrating it, a supporting frame therefor comprising a unitary sheet of metal shaped to provide a base plate, a pair of spaced parallel side bars located substantially in a common plane with said reed and base plate, said side bars being attached at their one end to opposite sides of said base plate, a top plate attached to the other ends of said side bars and lying in a plane at right angles to said first-named plane and being disposed symmetrically with respect to said base plate, said reed being attached to said base plate, said electromagnetic means being adjacent said top plate, a pair of movable contact arms attached to said reed and extending in opposite directions at right angles to its plane of vibration, and two sets of stationary contact members respectively positioned for alternating engagement with each of said movable contact arms.

6. In a vibrator having a vibratory reed and electromagnetic means for vibrating it, a supporting frame therefor formed from a single sheet of metal and comprising a base plate, a top plate and spaced side bars connecting them, said reed being disposed between said side bars, being attached to said base plate and adapted to vibrate at right angles to the plane of said base plate and side bars, said top plate being disposed in a plane at right angles to said common plane and to the plane of reed vibration, said top plate having central aperture in line With said reed in its neutral position, and a pair of apertures equally spaced from said central aperture at respectively opposite sides of said neutral position.

7. In a vibrator, a reed, an armature on the free end thereof, supporting means for said reed, a top plate located in a plane at right angles to said reed, a permanent magnet attached to said top plate and having its opposite poles adjacent said armature in the plane of vibration of said reed, a driving coil surrounding said armature, a pair of movable contact arms attached to said reed below said driving coil and extending in opposite directions at right angles thereto in its plane of vibration, a pair of contact arms attached to said supporting means and extending substantially parallel with said movable contact arms, and coacting contact elements on the free ends of said contact arms.

References Cited in the file of this patent UNITED STATES PATENTS Huetten Feb. 11,1947 Collins et a1 Dec. 30, 1947 Aust June 14, 1949 Eannarino Nov. 1, 1949 Huetten Aug. 5, 1952

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