US1942023A - Interrupter - Google Patents

Description

Jan. 2, 1934.

E. E. FRI-:Y 1,942,023

INTERRUPTER Filed Feb. 6, 1933 Sme/whom fw@ W Patented Jan. 2, 1934 IN TERRUPTER Elmer E. Frey, Los Angeles,

Kittle Manufacturing Co.,

Calif., assigner Los Angeles, Ca

a corporation of California Application February 6, 1933.

4 Claims.

This invention relates to electric interrupters, and particularly to magnetically operated contact devices for momentarily iiashing electric lamps at predetermined intervals.

It is common practice to illuminate certain street traliic signals, such as stop signs, so that they will display a warning to traffic at night as well as during the day. Various types of electric lamps have been used for this purpose, and in many instances electrically operated flashers have been employed to flash the lamp to make it more effective as a. warning signal.

Such signs have usually been energized from commercial circuits under which conditions it was not essential that the lamp and interrupter be extremely economical of current, because of the relatively low cost of energy supplied from commercial power circuits.

To avoid the expense of connecting traflic signals to commercial power mains which usually involves the installation of underground wires, traffic signals having self-contained batteries for energizing the lamp have come into use. These signals usually utilize gaseous discharge lamps of the neon type which are periodically flashed by momentarily applying current from thel battery to the primary winding of a step-up transformer, the secondary winding of which is connected across the lamp terminals. Gaseous discharge lamps of the type described, although requiring a high potential, use very little current, and the total energy required for the lamp is so small that it is comparable in magnitude to that required to operate the interrupter for flashingthe lamp. The over-al1 efficiency of a battery-operated signal, therefore, depends very largely on the eiiiciency of the interrupter used.

An object of the present invention is to provide an interrupter that requires very little energy for its operation.

Another object of the invention is to provide an interrupter that is reliable in operation and will continue to operate for long periods without attention.

vide an interrupter that is inexpensive to manufacture.

A feature of the invention is an interrupter so designed that it can be conveniently mounted in a tubular column for supporting a traine signal.

Another feature of the invention is an interrupter having few parts and the moving parts of which are not subject to excessive wear in operation.

Other objects and features of the invention will Still another object of the invention is to pro- Serial No. 655,

be apparent from the tion, which refers to In the drawing: Figure 1 is a fron to lif., l

following detailed descripthe drawing.

t elevation view of an interrupterV in accordance with the invention; and Figure 2 is a side elevation view of the same interrupter,

The interrupter and transformer `assembly herein described is adapted for insertion in the tubular supporting column of a trafc signal and is therefore disclosed as supported from the top of a column lwhich has been broken away to disclose the `'interrupter construction.

My unit comprise s a transformer mounted in a tubular transformer case 2, which, as already indicated, is supported from the top of the column l by an outwardly extending .flange 3 at the top of the transformer case. The upper end of the transformer case 2 is inset as shown and is provided with a center plate 4 and an annular ring 5 extending therearound for forming the connection between the transformer and the secondary winding of a neon lamp. Thus the head containing the lamp rests upon the upper end of the column 1 and is provided with downwardly depending brushes which contact with the plate 4 and the ring 5 to complete the connections from the transformer to the lamp.

The interrupter p roper, which constitutes the invention, comprises a supporting panel 6 which may be molded from any desired insulating material having the requisite mechanical strength and has horizontally extending iianges 7 and 8 at the top and bottom,

respectively. The top ange 'I is provided for the purpose of attaching the panel 6 to the lower ing 2. Thus I have end of the transformer housshown the ange 7 secured to the transformer casing by screws 9.

ng and breaking elements proper or my interrupter comprise a stationary contact 10 and a movable contact 11. The stationary contact l0 is mounted upon the end of The circuit-maki an adjusting screw 12 threaded into a supporting member 13 secured to the base plater 6. A set-screw 14 is provided to clamp the adjusting screw 12 against further rotation after it has been properly adjusted.

The movable contact 11 is mounted upon one end of a flexible spring supporting strip 15, the

other end of which or by welding or soldering,

is secured, as by a screw 16,

if desired, to an armature 17 which extends vertically and is pivotally mounted to the base-plate 6 at its lower end by a pivot screw 18. The strip 15 is secured to the armature 1'7 very close to its pivot point, as

shown. A delicate spring 19 connects the armature 17 to a metal plate 20 (upon which the pivot screw 18 is mounted) for insuring a good electrical connection between armature 17 and the plate 20. A binding post 21 is also provided on the plate 20 to facilitate making external electrical connection thereto from the battery which operates the interrupter.

In operation, the armature 17v isvibrated" at" a desired slow rate to make and break electrical connection between contacts 10 and 11 by means of an electro-magnet 22 and an oscillatable` member 23.

Thus the oscillatable member 23 preferably comprises a disc having a shaft.24,f the-ends lofE which are supported in a rear pivot? bearing 25" and a front pivot bearing 26, these pivot bearings being supported in fixed position byy a U- shaped supporting arm 27 secured to the panel 6. The rear bearing 25 may comprisesimply a hole drilled in the rear arm of the member 27 and the front bearing26'comprises a screw having a depression-in the inner endthereof'to receive the shaft 24. The front bearing screw 26 can'b'e adjustedin or4 out by turning it'in the arm 27, it' being threaded into this arm, and locking it indesired position with "a locknut 28. Disc 23 is provided with a pin 29 projecting forwardly'from the Afront face for engagement with theupper endof thearmature 17 and is provided witli'astop-pin 30,v which is shown as a screw, positioned substantially opposite the pin 29'.l 1:"i`ri-29-isV slightly heavier than the' stopscrew 30 so that in its' normal Iposition of rest'the disc 23`assumes` a position inwhich the pin 29 is inlowermost positioneither' in'conta'ctwith or'y closely adjacent'tothe'armature 17.

Tolimitthearc ofoscillation of the disc 23 and'prevent excessive motion thereof, a stop' springl, whichisspiral in shape; is secured at itsinner endto the bearing supporting member27,' and 4has its outer end positioned to intercept ther-stop screw 30 'when the vdisc 23has operated; through4` a desired angle, approximately 90", in'a countercloclnivise` direction from its normali position of f rest'y (the position shown in Fig; 1).

"Il'e` armature 17 is soI` positioned that' its weightinorma'lly' maintains it in the position slown'irrFig.` 1, in which' it is substantially in contact with the pole piece ofthe electromagnet 221r If fdesired, the connecting springlQ may be deslgn'edto-I alsoexert a slight restraining force tending to hold `the armature" against' the pole of "the'ielectromagnet. In this position the contact-s 1`0a'ndl1 areseparated so that the'electrical tcircuit through the electromagnet to the primary' wind-ing'ofthe transformer 2"is open. This circuit extends lfrom-the `binding post' 21,

y previously referredito, to a second binding post 32",? asl-follows:` The binding-post 21 is'connectedV through the spring conductor 19 to thearmature' 17`andff'th'encethrough the spring contact supporting' strip l5f-to the movable contact 11. The

fixed contactlO is in turn connected through its supportingfbracket'l and a lead vwhich extends4v back of- 'the panel 6, to a binding post 33 connected with a wire 34 leading to one end of 'theprimary winding of the transformer within the case 2. Thefot'herend of thev primary winding-of the transformer isconnected by a wire 35 to a bind'- ing-p'ost 36: which'inturn is connected by a wire' 37;V extending back! of thepanel 6 through theK windingof 'the electromagnet 22 to the binding post 32;-pre`viously"referred-tm A battery yfor op# erating the device is connected across the binding posts 21 and 32, and is shown schematically at 38.

To reduce sparking between the contacts 10 and 11, resulting from the inductive reactance of the primary winding of the transformer connected in series therewith, a condenser 39 is preferably connectedv across the bindng posts 33 and 36. 1n theni'o'delv shown in the drawing, this condenser 39 is-of a-conventional tubular type and is supported in position by clips secured to the ends thereof which are clamped beneath the binding posts-33 and 36, the clips serving to both physically support the condenser and to form the electrical connections thereto.

Tliedevice operates as follows:

Since, asI previously stated, the armature 17 in its normallposition of rest lies adjacent the pole piece of the electromagnet 22 in which position the contacts 10 and l1 are separated, the device is in stable equilibrium, and is therefore not selfstarting. It is started by initially rotating the disc 23 a short distance in a counterclockwise direction and releasing it. As a result of the fact that the pin 29 is heavier than thestcp-screw 310, the disc, when released, is in an unbalanced condition and rotates in a clockwise direction. Since the disc is veryfreely supportedin the pivot bearings 25 and 26, it accelerates its motion until the pin 29 strikes the upper end of the armature 17 and carries the latter away from lthe-pole piece of the electromagnet 22 a sufficient distance to bring the movable contact 11 against the fixed contact 10. r1`his closes the electrical circuit previously traced from the battery 38 through-the primary winding of the transformer within-the case 2 and through the winding-of the electromagnet 22. The electromagnet 22 is thereupon energized and immediately attracts the armature 17 causing it to move sharplyto the right against the pole piece of the magnet 22 and simultaneously imparting an impulse to the disc 23 through i pin l29, causing the disc 23 to swing ina counterclockwise direction.

The winding of the electromagnet- 22 is so designed that when the battery 38 is at` full strength, (as immediatelyafter a new battery 'has been installed), the disc 23 is swung approximatelyV far enough to bring the stop screw 30' into contactwith the spring member 31 which serves 125 to limit the motion of the disc and prevent it goingy all the way around.

Obviously if the disc oscillated throughmore than half a revolution it would tend to come to rest with the pin 29 against the rear side of-30 armature 17 and would be inoperative.

Of course as soon as the electromagnet 22 has been energized and attracts the armature 17, it opens the contacts 10 and 11, thus breaking the` electrical circuit, which is the desired function 13 of the device. The armature 17, however, willl remain inits forward position againstthe pole piece of theelectromagnet 22, because thatis its position of stable equilibrium, until thedisc completes-its oscillation in a'counterclockwise direction, reverses its swing, and again brings'thepin' 29 into contact with the armature 17 to move'- it away from 1the magnet, closethe'contact "l1 -on the contact'lO, and-thereby exciteth'e electro- 14g magnet 22to attract thearmature 17 and impart L a new.' impulse Ito l the' discV '23.

It is therefore apparent thatfafterbeing once-y set inoperation the'device will function continuously until the battery 38 becomes too weak-i5() to energize the electromagnet 22 sufficiently to swing the disc 23.

The device described has been found to be extremely economical of current. This is due primarily to the fact that the contacts 10 and 11 are closed only momentarily during each cycle of oscillation, the period during which they remain closed being substantially not longer than that necessary to properly excite the transformer. On the other hand, the time elapsing between successive closures of the movable contact l1 on the xed contact 10 is relatively long because of the time required for the disc 23-to complete its swing in a counterclockwise direction, in response to an impulse transmitted to the pin 29 by the armature 17, and then reverse its direction of movement and again impact the pin 29 against the armature 17. This period, of course, may be varied between wide limits by varying the relative weights of the pin 29 and stop-screw 30 or by adding other weights to the disc at different points thereon. To facilitate the addition of other weights for changing the period of oscillation of the disc, it may be drilled at intervals about the periphery, as shown at 40.

The interrupter described is particularly designed for minimum current consumption, and it is for that reason the disc 23 is preferably so balanced that when it is at reast the pin 29 barely rests against the armature 17 and does not exert suiiicient force against the armature to close the contacts 10 and 11. It is to be understood, however, that by increasing slightly the weight on the right side of the disc it maybe made to exert sufficient force, when at rest, against the armature 17 to close the contacts 10 and 11, in which case the device will start automatically in response to closure of the current supply circuit. With the latter adjustment, of course, more energy is required to rotate the disc in counterclockwise direction, and, therefore, the current required for operation is greater.

The device is particularly reliable and positive in operation because of the fact that the armature 17 is moved to close the movable contact 11 against the xed contact 10 by impact of the pin 29 against the upper end of the armature. The armature itself is relatively light in weight so that when the pin 29 strikes it, it moves to the left very readily andk forces the contact 11 into rm engagement with the contact 10. Furthermore, the spring contact supporting strip 15 yields slightly in response to forward movement of the armature 17 after the contacts have closed, thus producing a sliding, lateral motion of the contact 11 against the contact 10, which sliding or wiping motion has a cleaning effect upon the contact surfaces.

Experiments have shown that a dry battery comprising twelve standard cells will operate a neon lamp traine signal for approximately a year when the circuit is interrupted with the device described. Furthermore, the interrupter requires no maintenance of any sort during I do not limit myself to the exact construction herein set forth, which may obviously be varied in detail without departing from the spirit of this invention, but only as set forth in the appended claims.

I claim:

1. An electrical interrupter comprising an electromagnet, an armature pivotally mounted for movement toward and away from said magnet, a back contact cooperating with said armature to close an energizing circuit for said mag'- net when the armature is moved a predetermined distance away from said magnet, said armature in its normal position of rest being toward said magnet and away from its back contact, an oscillatable member positioned to impinge against said armature near one end of its path of oscillation to deiiect said armature away from said magnet and against said back contact, thereby energizing said magnet to attract said armature away from the back contact and at the same time impart an impulse to the oscil latable member to maintain it in oscillation.

2. An electrical interrupter as described in claim 1 with a resilient stop member positioned to contact with said oscillatable member at the opposite end of its path of oscillation to limit the arc of oscillation of said member.

3. An electrical interrupter as described in claim 1, in which said oscillatable member comprises a disc pivotally mounted to oscillate in a vertical plane, said disc having a pin projecting' from one face thereof for striking said armature, and means including said pin for slightly unbalancing said disc, whereby it seeks a position of equilibrium in which said pin lies close to said 115 armature.

4. An interrupter comprising a disc having a central shaft, means for pivotally supporting said disc shaft, a pin projecting from said disc and unbalancing the disc, whereby the disc normally 120 rests with the pin in lowermost position, an armature pivotally supported below said disc and extending substantially vertically upward into engagement with one side of said pin, an electro- 'magnet positioned to rotate said armature toward 125

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