US2974207A

US2974207A - High speed chopper

Info

Publication number: US2974207A
Application number: US737923A
Authority: US
Inventors: Herbert I Chambers; Albert W Fischer
Original assignee: Consolidated Electrodynamics Corp
Current assignee: Consolidated Electrodynamics Corp
Priority date: 1958-05-26
Filing date: 1958-05-26
Publication date: 1961-03-07
Anticipated expiration: 1978-03-07

Description

March 7, 1961 H. l. CHAMBERS ET AL HIGH SPEED CHOPPER Filed May 26, 1958 INVENTOR. HERBERT I CHAMBERJ ALBERT M FISCHER BY United States Patent HIGH SPEED CHOPPER Herbert I. Chambers and Albert W. Fischer, Pasadena,

Calif., assignors, by mesne assignments, to Consolidated Electrodynamics Corporation, Pasadena, Cali, a corporation of California Filed May 26, 1958, Ser. No. 737,923

8 Claims. (Cl. 200--90) This invention relates to electromechanical devices for making and breaking electrical'circuits, and more particularly, is concerned with a high speed device for making and breaking circuits which can be used as a relay or as a high speed chopper.

Magnetically operated switches take a variety of forms, such as relays for switching large currents in response to control signals of much smaller levels. Also, magnetically operated mechanical switches are used for chopping D.C. signals at the rate of an AC. signal applied to the electromagnetic circuit. The relay-type of device may also be used for commutating or switching in a scanning manner for discrete periods of time. Whatever form the electromechanical switching device takes, its frequency of operation is limited by the relatively large mechanical mass required to provide suitable magnetic properties, and, in addition, is limited by the large equivalent electrical mass in the form of inductance of the electromagnetic circuit. By very careful design, both the mechanical and electrical mass of such relay devices have been reduced to improve performance, but reliable operation of such devices at frequencies as high as 1,000 cycles per second, for example, is not generally attainable.

The present invention is directed to an electromechanical switching device which may be used as a simple relay, or a chopper, and capable of opera-ting reliably at frequencies of several thousand cycles and even higher. This is accomplished by reducing the mechanical mass to that of a single fine conductive wire, and by reducing the electrical equivalent mass by using a permanent magnetic field.

In brief, the relay apparatus of the present invention includes permanent magnet means defining an elongated magnetic flux gap. A flexible current-wnductive element is supported in the gap, the supporting means including at least one resilient support at one end of the conductive element. Means is provided for passing a current through the conductive element for deflecting the conductive element laterally due to the interaction of the current in the magnetic field in the gap. The resilient support permits the element to deflect laterally by allowing the ends of the element to move closer together. Contact means is provided which is actuated by the lateral movement the element in response to the current applied therethrough.

For a more complete understanding of the invention, reference should be had to the accompanying drawing, wherein:

Fig. 1 is an elevational view partly cut away, showing a circuit-breaking device according to one form of the present invention;

Fig. 2 is an end view' of the form of the invention shown in Fig. 1;

substantially on the line 4-4 of Fig. 3; and Y NSC Fig. 5 is a sectional view taken substantially on the line 5--5 of Fig. 3.

Referring to the form of the invention as shown in Figs. 1 and 2, the numeral 10 indicates generally a frame which is substantially channel-shaped, with the righthand upright member 12 extending considerably higher than the lefthand upright member 14. Mounted to the frame member it) is a magnet block 16, which may be of Alnico magnet material. The block is secured to the frame member 10 by means of screws 18. The magnet block 16 extends between the two upright end portions 12 and 14 of the frame member 10.

A pair of

pole pieces

20 and 22 are bolted on either side of the magnetic block 16, as by means of bolts 24 extending through the block 16. The

pole pieces

20 and 22 project upwardly and extend the full length of the block 16 between the end portions 12 and 14 of the frame 10. The upper end of the pole pieces 21) and 22 respectively have inwardly projecting

portions

26 and 27 which are tapered along their inner opposed edges to define an elongated magnetic gap 28. It will be apparent that the gap extends the full length of the

pole pieces

20 and 22.

A fine conductive wire element 30 is secured at one end to the upright portion 12 of the frame member 10. The wire element is supported at the other end by a cantilever spring 32 which is curved at its upper end as indicated at 34. The fine wire element is drawn across the curved upper end and anchored as by means of solder or other suitable means at its end 36. The cantilever spring 32 extends downwardly to a point opposite the lower end of the frame 10 and is rigidly secured at the lower end by means of a screw 38 which clamps the cantilever spring 32 together with a set of contact elements, to be hereinafter described, between a plurality of insulating washers to the frame 10. Thus the cantilever spring 32 applies tension to the wire element 30, and at the same time supports it in position in the magnetic gap 28 formed byv tion at the contacts if so desired. A plurality of insulat-v ing washers, as indicated at 54, clamp the

cantilever spring elements

32, 50, and 52 in conventional manner of multi-contact relays. Conductive leads 56 and 5'3 are provided for bringing out electrical connections to the contacts 40 and 42 respectively.

In operation, a potential is applied between the ends of the fine wire element 30, as by connecting a potential source between the lower end of the cantilever spring 32 and the frame In. The resulting current passing through the Wire element 30 interacts with the magnetic field in the gap 28 to produce a lateral displacement of the wire element 30. This lateral displacement is in a ventical plane in the arrangement shown in Figs. 1 and 2.

Lateral displacement of the wire element 30 causes the ends thereof to move closer together. As a result, the cantilever spring support element 32 is caused to move'to the right so as to close the contacts 42 and 48 and to open v the input causing contacts to open and contacts to close An alternating signal can be applied across the input if desired, causing the spring element 30 to vibrate at the frequency of the input signal. As a result, the contacts are caused to make and break at twice the, frequency of the input signal, resulting in a high frequency cliop'per.

An alternative embodiment of the present invention is shown in Figs. 3, 4 and 5. in this arrangement, the frame of the device consists of an upper plate 60 and a lower plate 62, a pair of cylindrical members 54 and 6:5, and a central plate 63. The central plate is clamped between the two cylindrical members 64 and es, and end plates 6b and 62 are clamped to the outer edges of the

cylindrical members

64 and 66 by bolt members, such as indicated at '70, which are secured to the lower plate 62 and have nuts 72 which clamp against the upper end plate 60. Annular insulating spacers 7d and 7d are preferably provided between the upper and lower plates 6d and 62 and the cylindrical members 64 and ed to insulate the plates electrically.

A conductive Wire element 73 is anchored at either end respectively in the upper and lower plates so and 62. The wire element '78 is formed with crimped sections 30 to provide flexible tensioning of the Wire element 7%, or may have a tension spring similar to 32.

As best seen in Fig. 4, the central plate 62; is provided with a central opening 82 through which the wire element 73 passes. The central plate 68 is cut to form a pair of integral cantilever supported

adjustable arms

84 and 86. Suitable screw means, such as indicated at may be provided for bending the arms toward each other to provide an adjustment of the spacing between the outer ends of the

cantilever arms

84 and 86.

The wire element 78 is immersed in a magnetic field formed by a pair of pole pieces positioned above and below the central plate 68, the pole pieces being indicated at 90 and 92. The pole faces are secured to blocks of magnetic material such as Alnico, as indicated at 94 and 96, the blocks having curved surfaces to fit against the inner surfaces of the cylindrical members 6 and 66. With the wire element immersed in a magnetic field, current passing through the magnetic element will cause it to deflect. The current may be connected by suitable leads connected to the

end plates

60 and 62. These end plates are insulated from each other by virtue of the

annular insulating rings

74 and 76 and by insulating bushings 98 through which the connecting bolts 70 pass.

Lateral movement of the wire element '78 in response to current passed therethrough is utilized to maize and break contacts, the contacts being best shown in Fig. 4. One set of contacts comprises a spring wire 100 which is anchored in a hole 102 in the central plate by a suitable insulating cement. The wire 100 projects into the opening 82 in the central plate and is positioned to one side of the wire element 78. The wire contact element 100 is normally in contact with an associated stop lil' i which is secured in an opening 106 in the adjustable cantilever arm 34 by suitable insulating cement.

Similarly, a wire contact element 103 is secured in a hole 110 in the central plate and projects into the opening 82 to the opposite side of the wire element 73 from the contact element 100. An associated stop element 112 is secured in an opening 114 in the cantilever arm 86.

The wire element 78 is provided with a small insulated contact 116 with a ribbon pigtail 117, the contact 116 engaging the wire contact elements 100 and 103. The pigtail 117 extends to an insulated support pin 119 for making an external electrical connection. ner, lateral displacement of the wire element 7% in two directions respectively closes the contacts tilt) and 163 with contact 116. Screws 88 adjust the position of the

stops

104 and 112 to vary the spacing between the

contacts

100 and 108. Electrical connections are made to the pigtail 117 and the

contact elements

100 and 108.

Sponge rubber damping pads 118 are preferably provided, which are. cemented. into position and fillthe space In this manbetween the contact elements and 108 and the sides of the opening 82. These pads prevent bouncing or vibration of the contact elements 160 and 108.

The entire assembly is mounted inside a protective housing which is in two parts including an upper cupshape cover 120 and a base member 122. The base member and cover member are telescopically joined and brazed together at the joint to provide a hermetically sealed container. Electrical connecting pins 124 are provided in the base member 122, which extend through glass seals 126 for providing electrical connections to the element 78 and the

contacts

100, 103, and 116. The wire connections have not been shown for the sake of clarity.

From the above description it will be seen that an electromechanical circuit breaking device has been provided which is capable of operating at high speeds. The device can be used as a relay or as a chopper. The mechanical inertia of the device is very small so that the moving mass as represented by the wire element is extremely small. The electrical equivalent inertia is very small because the inductance of the single wire conductor is of course extremely small. Because of the small inductive fields, the noise level is very low so that the device provides excellent switching performance.

What is claimed is:

1. A high speed switching device comprising a flexible current-conductive straight wire element, magnetic means defining an elongated magnetic gap, means for supporting the conductive element in the gap inciuding a resilient support at one end of the element for maintaining tension on the Wire element, the elongated magnetic gap extending substantially the full length of. the flexible element, means for passing a current through the flexible element, the current producing a lateral deflection of the flexible element due to the interaction of the current and the magnetic field in the gap, the resilient; support permitting the element to deflect laterally by allowing the ends of the element to move closer together, and contact means actuated by movement of the element in response to the current applied through the element, the contact means being electrically insulated from the flexible element to provide switching of an isolated circuit.

2. Apparatus as defined in claim 1 wherein said resilient support includes a cantilever spring to which the element is secured at one end, and the contact means includes contacts insulatedly supported by the cantilever spring and movable therewith and fixedly supported contacts positioned adjacent the moving contacts, whereby the contacts are brought in and out of engagement by movement of the flexible element in response to variations in the current passed therethrough.

3. Apparatus as defined in claim 2 further including a source of alternating current electrically connected across the flexible element for imparting a periodic movement to the flexible element and associated cantilever spring, whereby the contacts are periodically engaged to efiect a chopper operation.

4. A high speed switching device comprising a flexible current-conductive wire element, magnetic means doth ing an elongated magnetic gap, means for supporting the conductive element in the gap under tension, the eiou-- gated magnetic gap extending substantially the fuli length of the flexible element, means for passing a current through the conductive element, the current producing a lateral deflection of the center of the conductive wire element due to the interaction of the current and the magnetic field in the gap, and contact means actuated by lateral movement of the wire element in response to the current applied through the element, the contact means being electrically insulated from the flexible element to provide switching of an isolated circuit.

5. Switching apparatus comprising a main frame including a pair of spaced plates, a wire element extending between said plates and resiliently supported therefrom,

a pair of contact elements positioned respectively on either side of the wire element, a contact sleeve insulatedly mounted on the wire element and adapted to engage the contact elements when the center region of the Wire element is laterally displaced, means for resiliently supporting the contact elements from the main frame, a pair of adjustable stops normally engaging respectively each of the first pair of contacts for adjusting the spacing of the contacts, and magnetic means mounted on the main frame including pole pieces positioned on either side of the wire element for immersing the wire element in a magnetic field.

6. Switching apparatus comprising a main frame, a

wire element resiliently supported by the frame, a pair of contact elements positioned respectively on either side of the wire element, a sleeve contact on the wire element adapted to engage the contact elements when the center region of the wire element is laterally displaced, means for resiliently supporting the contact elements from the main frame, a pair of stops normally engaging respectively each of the first pair of contacts, and magnetic means mounted on the main frame including pole pieces positioned on either side of the wire element for immersing the wire element in a magnetic field.

7. Switching apparatus comprising a main frame, a wire element resiliently supported by the frame, a pair of contact elements positioned respectively on either side of the wire element, means for resiliently supporting the contact elements from the main frame, whereby the contact elements' are respectively movable with lateral movement in opposite directions of the wire element, a contact insulatedly secured to the wire element and movable 6 therewith, displacement of the last-named contact by the wire element moving the contact into and out of engagement with the first pair of contacts, and magnetic means mounted on the main frame including pole pieces positioned on either side of the wire element for immersing the wire element in a magnetic field.

8. Switching apparatus comprising a main frame, a wire element resiliently supported under tension by the frame, a pair of contact elements positioned respectively on either side of the wire element, means for resiliently supporting the contact elements from the main frame, a contact member secured to the wire element and engaging the contact elements, whereby the contact elements are respectively movable with lateral movement in opposite directions of the wire element, magnetic means providing a unidirectional magnetic field mounted on the main frame including pole pieces positioned on either side of the wire element for immersing the Wire element in a constant magnetic field, and means for passing an alternating current through the wire element to cause the wire element to oscillate in the magnetic field.

References Cited in the file of this patent UNITED STATES PATENTS Cook Feb. 14,