US2427898A

US2427898A - Vibrator

Info

Publication number: US2427898A
Application number: US629556A
Authority: US
Inventors: Burrows Frederick Arthur
Original assignee: Oak Manufacturing Co
Current assignee: Oak Manufacturing Co
Priority date: 1945-11-19
Filing date: 1945-11-19
Publication date: 1947-09-23
Anticipated expiration: 1964-09-23

Description

Sept. 23, 1947. F. A. BURROWS VIBRATOR Filed Nov. 19, 1945 fiwe/z for fiea erz'zielfiarmva fly RM R NA Jig Patented Sept. 23, 1947 VIBBATOB Frederick Arthur Burrows, Wilmette, 111., assignor to Oak Mfg. 00., Chicago, Ill., a corporation of Illinois Application November 19, 1945, Serial No. 629,556

2 Claim.

This invention relates to a vibrator and particularly .to a high frequency vibrator for use in interrupting currents. As is well known, automobile and farm radios relying upon batteries as a primary source of power utilize vibrators for interrupting direct current and stepping up such interrupted currents in a transformer. The resuiting stepped-up voltages are then used in a conventional manner for supplying the plate circuits of vacuum tubes.

While conventional vibrators operated at around 100 to 110 cycles are highly satisfactory, there has long existed a demand for vibrators capable of operating at substantially higher frequencies. As is well known, the higher the frequency of interruption, the smaller becomes the physical size of transformer and filter components. While attempts have been made to provide vibrators operating at high frequencies, such attempts have generally been unsuccessful. In the main, such attempts have consisted in utilizing conventional vibrating structures and merely increasing the stiffness to thereby increase the resonant frequency of the vibrating system. The resulting high frequency vibrator has invariably had contact trouble and spring breakage.

In accordance with the invention, there is pro- .vided a structure which is mechanically different than a conventional vibrator and provides satisfactory operation at frequencies between 200 and 300 cycles per second. In general, a structure embodying the invention utilizes a solenoid instead of an electromagnet for generating the magnetic force necessary to attract an armature. An armature cooperates with the solenoid, and the relationship between the two is such that the solenoid goes through the position at which it normally would rest upon solenoid energization. In distinction to present vibrators where the armature sweeps past a pole face, the driving circuit may be maintained energized up to the dead center position of the armature. In the conventional type of vibrator, the driving circuit energization period is more critical with respect to the armature rest position. In general, it is preferred to mount the armature at opposite ends thereof on springs and utilize the armature movement for driving contacts. As will be apparent later, various modifications of the invention are possible, some of these modifications being shown in the drawing.

Thus, referring to the drawings, Figure 1 shows a structure embodying one form of the invention, the structure being shown in elevation with the solenoid and stack being shown in section. Fig- 56 ly in section, of a push-pull form of vibrator. Referring now to Figures 1 and 2, the structure comprises frame members It and ll of steel, brass or any other metal or material. Members l0 and i I have one end Joined by cylinder i2 over which coil i3 is wound. Cylinder l2 preferably is of magnetic material and has smooth bore it within the same in which armature i5 is adapted to operate. Armature l5 may consist simply of a ferromagnetic machined cylinder so proportioned as to be freely movable within bore i4. Armature I5 is substantially shorter than the length of 0011 IS, the proportion as shown being somewhat greater than one-half. However, the proportion of cylinder length to coil length may vary within wide limits and will depend upon various factors such as armature travel, frequency of operation, ratio of coil diameter to coil length, flux density within armature i5 and the like.

Armature i5 is supported eccentrically of coil I2 by means of shaft IT. This may be of aluminum or brass and may pass through the center of armature l5 or may be secured thereto in any desired fashion. While shaft i1 is preferably non-magnetic, its small diameter makes it unimportant whether it is magnetic or non-magnetic. Shaft I! has threaded ends l8 and i9.

Frame members l0 and II at the other ends carry outwardly extending stacks2ll and 2|. Between the ends of members Ill and II is block 22 of metal or insulation. The stacks are bolted as shown to provide a rigid structure. Stack 20 carries a pair of fixed

contact supporting members

23 and 24 of suitable spring material such as spring steel or beryllium copper. Contact carrying

members

23 and 24 are bent outwardly away from each other and carry fixed contacts 21 and '28. These contacts may be of any suitable material such as silver, tungsten, Or the like.

Cooperating with

fixed contacts

21 and 28 are

movable contacts

30 and 3| carried on spring arms 32 and 33 diverging from central spring supporting member 34. These arms may be riveted or otherwise fastened to member: 34. In the normal rest position of the vibrator,

movable contacts

30 and 3| are separated from the cooperating fixed contacts.

Center arm I4 extends upwardly from the stack and its free end 35, is suitably apertured and locked between nuts 36 on threaded end I8 of shaft l1.

Stack 2| carries fixed driving contact 31 mounted on spring arm 38 of the same general shape as arms 24 and 25. Cooperating with fixed contact I1 is movable contact 39 carried on arm 40 branching from sprin ll supported in stack 2i. Spring arm ll has its free end 42 suitably apertured and locked between nuts 43 at threaded end IQ of shaft l1.

As is well known, vibrators may either have the driving contacts in series With the driving coil or in shunt thereto. If the driving contacts are in series, the normal rest position of the vibrator is such as to have the contacts closed. On the other hand, if the driving contacts are in shunt to the driving coil, then the normal rest position of the contacts is open. In such a case, it is customary to dispose the driving coil in series with a primary winding of a transformer, all well known in the art. In this particular instance, the driving contacts are in series with driving coil I3, and these contacts are therefore normally closed.

The spring arms carrying the various contacts are adjusted so that, in the normal rest position, the driving contacts are closed as shown, and the power contacts are open. It is evident that the armature should be on the same side of the center of the coil as the driving contacts. When energized, driving coil I3 will generate a magnetic field tending to move armature l5 toward the left. This will tend to close

power contacts

30 and 21 and open drivin contacts 3'! and 39. As armature 15 moves into bore-l4, it reaches a dead center position where the effect of the magnetic field on the armature is a maximum, The driving contacts should be so adjusted as to open at or just prior to dead center.

By adjustment of the contact spacing, mass of the armature and vibrating system, spring tension, it is possible to provide for such an amplitude of movement of armature l5 as to effect a desired and satisfactory closure of power contacts l and 21 without undue hammerin of these contacts. When driving contacts 3'! and 39 are opened, coil I3 becomes deenergized. Thus, the energy stored in the springs of the vibrator tends to return armature l toward a normal rest position. In this return movement,

armature l5 will overshoot the position indicated in Figure 1, thus

closing power contacts

34 and 28. At the same time, driving

contacts

39 and 31 will be closed. By proper design of the inductance of the coil and adjustment of driving contacts, it is possible to provide for a closure of the driving contacts so that a retarding force or movement ofthe armature toward the right of the position shown in Figure 1 will be generated.

It is, thus, clear that the power contacts may be closed without undue hammering. By virute of the arrangement of the contact supporting arms, a wiping action of the contacts will also result, thus tending to keep them clean. In general, the driving contacts may engage with more force than the power contacts. The driving contacts as a rule do not carry very heavy currents so that but little contact trouble is experienced.

It is evident that driving

contacts

31 and 39 may be entirely eliminated, and coil l3 may be 4 connected across one of the power contacts, contacts 21 and II in this particular case.

The amplitude of vibration of armature II is preferably small enough for satisfactory vibrator operation. The clearance between the armature and bore of cylinder I! should be great enough so that no physical contact or sticking can occur.

Referring now to Figures 3 to 5 inclusive, a modified structure is shown wherein the spring mounting for the contacts and armature has been changed. In this particular construction, stacks 50 and Si carry fixed contacts I! to 54 inclusive. These contacts may be mounted on straight spring arms with

contacts

52 and 53 being power contacts and I4 being a driving contact. Frame members I II and II' extend below coil l3 and carry stacks 50 and I1. Stack 58 carries spring 68 at the free end of which are mounted movable powercontacts OI cooperating with fixed contacts 52 and II respectively. Spring 58 has portion 5| cut out and small spring 82 left therein. Small spring 62 is fastened to shaft ll' in any suitable fashion.

Stack 51 carries spring arm 04 at the free end of which movable driving contacts 85 is secured. Spring arm 84 is rigidly fastened to shaft H as shown, and may have the same cut-out con struction as spring arm 50. By controlling the spacers in the various stacks, as well as by bending the various spring arms, adjustment of contact spacing may be made.

Referring now toFigure 6, a push-pull type 'of construction is 'shown wherein driving coils Ma and 13b are provided. Shaft Ha carries armatures l5a and 15b spaced as shown. These armatures are disposed axially away from the centers of the corresponding actuating coil. Power contacts 21", 2|, 30 and II are mounted as shown on spring arms carried by stack 20. Spring arm 34' carries driving contact 10 c0- operating with fixed driving contact ll carried by spring arm 12 supported in stack 13.

Stack 2| carries spring arm 15 riveted to shaft l1. Spring arm 15 carries driving contact 16 at the free end thereof, this cooperating with contact H carried by stack". Inthe normal position of the device, one of the pairs of driving contacts, here shown as 16 and I1, is normally closed. Upon the energization of the circuit with the connections as shown, coil lib will be initially energized. Thus, armaturecisb. will be pulled inwardly to the left. After driving contacts 16 and 11 open, driving contacts I0 and 1! will close. It is understood that both sets of driving contacts will have no over-lapping closure time. When driving contacts H and 10 are closed, armature I in. will be pulled back into coil I341 tending to reverse the movement of the vibratory structure.

, It is clear, therefore, that a push-pull action will result.

It is understood that one movable driving contact may cooperate with a fixed driving contact on each side to alternately engage. Also, one armature, here l5a, may be disposed in a dead center position as the normal rest position. Thus, on closure of contacts .10 and II, armature l5a would be left of dead center.

The spring structure of the fixed and movable contact arms may be as shown in Patent 2,140,792. In addition, it is possible to utilize the bifilar construction disclosed in Patent 2,012,123 for reducing arcing at the contacts. The vibrator will have the connections shown and, in addition, will be connected to suitable batteries and transformers, all well known in the art.

What is claimed is:

1. In a vibrator, a solenoid including a magnetizing coil, supporting members extending to a supporting structure from said solenoid sides transversely of the solenoid axis, a rod and armature assembly disposed within said solenoid, leaf springs carried by said structure, said leaf springs being normally parallel to each other and normal to the solenoid axis and having cut-outs leaving small spring portions fastened to said rod ends, said leaf springs normally providing an eccentric rest position for said armature and permitting armature movement along said solenoid axis, contacts carried by at least one of said leaf springs, at least one stack carried by said structure, flxed contacts carried by said stack for cooperation with sald movable contact and conmotion; between said magnetizing coil and contacts for maintaining continuous vibration upon energization.

2. In a vibrator. a solenoid including a pair of magnetizing coils aligned in side-by-side relation and having acontinuous bore, supporting members extending from said solenoid sides transversely of the solenoid axis, a rod and two armatures disposed 'within said solenoids, leaf springs carried by said supports and being normally parallel to each other and normal to the solenoid axis and supporting said rod at the ends thereof to per- 6 mit said armatures to move axially within said bore, a driving contact secured to each spring,

fixed contacts carried by said supports cooperating with said driving contacts, said armatures being so disposed relative to said solenoids so that only one armature is in a dead center position at one time, one of said pairs of driving contacts being normally closed and connections between said solenoids and driving contacts whereby pushpull vibrator action occurs.

FREDERICK ARTHUR. BURROWS.

REFERENCES CITED The following references are of record in the file of this patent:

. UNITED STATES PATENTS Number Name Date 1,745,878 Trumpler Feb. 4, 1930 1,877,480 Osborne Sept. 13, 1932 2,284,891 Hartig June 2, 1942 2,140,792 Dressel et al Dec. 20, 1938 I 2,213,854 Wood Sept. 3, 1940 431,493 Van Depoele .July 1, 1890 545,149 Carpenter Aug. 27, .1895 1,124,470 LeBlank Jan. 12, 1915 1,855,859 Lesh Apr. 26, 1932 1,954,575 Pearson Apr. 10, 1934 2,253,267 Dietrich Aug. 19, 1941