US1654613A - Electric switch - Google Patents

Description

Jan. 3, 1928. 1,654,613

I. E. SMITH ELECTRIC SWITCH Filed March 8, 1926 Z 'i/q. 6

I 36 Fly. 5 29 33 i /37 14a /32 31 8 34 I INVENTOR Ira E. Sm z ill BY s mm Patented Jan. 3, 1928 UNITED STATES IRA E. SMITH, OF STOCKTON, CALIFORNIA.

ELECTRIC SWITCH.

Application filed March 8, 1926. Serial No. 93,050.

This invention relates to improvements in electric switches and particularly to one to be used in the current carrying lines of motors and the like.

The principal object of my invention is to provide an adjustable time limit, reclosing, no-volta-ge, magnetic switch; in which the magnet holds the main line switches closed, but is so constructed that if the power I goes olf the line for a short time as frequently happens and the magnet becomes deenergized, said'main line switches will be again automatically closed with the return of the current to the line, at any time within a certain predetermined and adjustable time limit.

This prevents the main line circuit from remaining open with every slight break of the current, and avoids necessity of having to operate a hand-switch to reclose the main line circuit every time the same is momentarily opened.

At the same time, the main line switch members always open and close with a quick movement, avoiding the burning of the contact points which would otherwise be had if the current should come on during the opening or closing movement.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings similar characters of ref erence indicate corresponding parts in the several views: I

Fig. 1 is a side elevation of my improved switch structure in closed position.

Fig. 2 1s a front elevation of the device.

Fig. 3 is a vertical section on the line 3-3 of Fig. 1 with the main line switch members opened but the magnet controlled switch member still closed. v

Fig. 4 is a similar section on the line 4-4 of Fig. 2, with the magnet controlled switch member about to open.

Fig. 5 is a front view of the dashpot control lever detached. 7

Fig. 6 is the wiring diagram of the circuits preferably employed in connection with my switch.

Referring now more particularly to the characters of reference on the drawings, the numeral 1 denotes a supporting panel, mounted on and projecting from which is a bracket 2 which supports a horizontally d sposed electro-magnet 3. Pivoted on the bracket below the. magnet is an armature '4 adapted to engage the core '5 ofthe magnet when the latter is energized, or to drop away from the same by gravity, the outward dropping movement of the armature being limited by a stop 6.

A panel 7 of insulation material is secured to the armature and extends arallel to the member 1 on both sides 0 the magnet. Flexibly mounted on the panel 7 centrally of its length and projecting thereabove is a contact finger 8 which is pressed toward the panel by a spring 9 but is prevented from contact with said .panel by an adjustable screw 10. The upper end of the contact finger 8 is adapted to engage a rigid terminal post 11 projecting from the member 1 above the magnet and of such length that when the magnet is energized and the finger 8 is bearing against said post, the end of the screw 10 is spaced some distance from the panel 7.

Flexibly mounted on the panel 7 on opsimilar contact fingers 12 and 12 pressed toward the panel by springs 13, and contacting with said panel when the latter is away from the magnet. Terminal posts 14 and 14 project from the panel 1 for engagement with the ends of the fingers 12 and 12? respectively when the magnet is energized. The length of the posts 14 and 14 is such that when the respective contact fingers are engaged therewith and the magnet is energized, said fingers are spaced slightly from the panel 1 as shown in Fig. 1. The width of this spacing however is considerably less than the distance between the screw 10 and the panel when the magnet is energized and the member 8 is engaged with its post 11.

'posite sides of the contact finger 8 are other Pivoted intermediate its ends on the panel 1 is a horizontal lever 15 having adjacent one end a vertical slot 16 to receive a pin or arm 17 which projects from the pivotal ear 4 of the armature "'4, the pivotal pin 18 of said ear lying in a plane between the armature and the lever.

The opposite end of the lever is connected to a vertical upwardly projecting plunger 19 which moves snugly in a cylinder 20 provided at its top with an outwardly opening check valve 21. This structure forms an ordinary dashpot arrangement. The cylinder 20 is swivelly supported from the panel 1 by abracket 22.

This switch structure is preferably Wired in connection with a starting and stopping switch S of'a type now on the market and such as is shown in Patent No. 1,477,834, and which comprises essentially a flexible self opening starting contact strip 23 normally spaced from a contact 24, a closing stop contact strip 25 normally engaged with a con tact 26, and a contact. 27 constantly engaged with both strips. These strips in turn are constantly engaged with each other at one end.

The circuit to my switch structure is arran ed as follows:

Tlie main power lines 28 and 29 are connected to the posts 14 and 14 respectively, while wires 30 lead from the strips 12 and 12 to a motor 31 or the like, fuses or circuit breakers 32 of suitable character being preferably interposed in the wires 30;

A wire 33 leads from the line 28 to the contact 24 of the switch S, another wire 34 leads from the contacts 26 to one terminal of the magnet 3; another wire 35 leads from the contact 27 to the contact finger 8; while a wire 36 leads from the other terminal of the magnet to the line 29. The post 11 is connected to the wire 33 by a wire 37.

With this arrangement if the current is in main lines but the starting switch member 23 is open, no current will pass to the motor, since the magnet 3 is deenergized and the switch members 12 and 12 are open. If the switch member 23 is closed against the contact 24, a circuit will be closed from the line 28,'through the wire 33, contact 24, strips 23 and 25 to contact 26, wire 34 to magnet 3, and through wire 36 to the line 29. The magnet is therefore energized, and the armature 4 is drawn toward the core 5, causing the contact fingers 8, 12 and 12 to be engaged with their respective posts. A circuit is therefore also closed from the main lines through the members 12 and 12 to the motor, and another circuit will be closed through the member 8.

This latter circuit serves to hold the magnet energized even though the contact 1nen1- ber 23 is permitted to immediately break from the contact 24 as it is intended to do. In this case the circuit through the magnet is still closed from the line 28,-.along the wire 33 to the wire 37 and post 11, across the finger 8, to and along the wire 35, to

the contact 27, along stop 25 to contact 26, v

along wire 34 to ma et 3, and along wire 36 to the line 29; Ti: magnet circuit will therefore remain closed as lon as the current is in the main line, or un'ti the member 25 is actuated to break from its contact 26, which operation of course opens the above described circuit and deenergizes the magnet.

When the magnet circuit is closed and the magnet is energized the member 17 is at the bottom of the slot 16 in the lever 15, holding the opposite end of the lever raised and the plunger 19 in its uppermost position in the cylinder 20.

Now in the event that the current goes off from the main lines for short periods, as frequently occurs, the following operations take place. 1

The magnet of course immediately becomes deenergized and the armaturewill drop away from the core 5. The first part of this movement of the armature and the parts connected thereto causes the member 17 to move to the top of the slot 16, thus far imparting no movement to the lever or to the dashpot plunger. The slot is designed of such length as to allow sufficient movement of the panel 7 to take place without moving the lever 15 to cause said panel to bear against the contacts 12 and 12, thus causing the latter to break from their posts. The initial outward movement of the panel 7 is quickened by the expanding action of the springs 13 tending to force the fingers -12 and 12 against the panel; or, since the fingers up to this time are immovably held against their contact posts, to pull the panel outwardly toward the said lingers. This provides for the necessary sudden opening or quick break of the main motor circuit, preventing the burning of contact points which would be had by a slow operation, in the event that the current was still on, and the stopping switch S was being used to intentionally halt the operation of the motor. This initial movement of the panel 7 is not suiiicient however to cause the contact 8 to break from its contact post 11, as this contact post is somewhat longer than the other posts and the finger 8 and its adjusting screw are therefore further away from the panel 7 than said other contact lingers.

As soon as .the member 17 reaches the top of the slot 16 it takes hold of the lever and thefurther out-ward movement of the panel is restrained and slowed down by the dashpot action. During this slow movement of the panel the latter gradually approaches the screw 10 and when it contacts with the same, the contact finger 8 breaks from the contact post 11, and the circuit can then only again be closed by a further operation of the starting member of the switch S. If, however. during the time the above described retarded movement of the panel is taking place, the current should come on again, the main switch contacts are immediately snapped closed again, since the magnet circuit will still be closed.

It will be noted that by reason of the adjusting screw 10, the distance the panel must 'lmove before it-engages said screw and causes the contact 8 to break from its post, may be having to maintain a hand pressure on the' same for a suflicient length of time to insure 'the main. switch dashpot functioning long enough to cause the magnet circuit switch to be opened. a It will be seen that the contact fingers 12 and 12 and the contact posts 1 and 14", form a double-pole switch, controlling a single circuit. It will be obvious however that one contact finger and its contact post would serve just as well to control the circuit. Hence in the claims, I have only defined one such finger and its contact post'for the main motor circuit;

From the foregoing description it will be readily seen that I have produced such a decally moving away from the magnet when vice as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in de-' tail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described my invention what I claim as new and useful and desire to secure by Letters Patent is:

1. A switch structure including a fixed electro-magnet, an armature movable to and from the same, a pair of independent contact fingers mounted in connection with the armature, fixed contact posts with which said contact fingers respectively engage when the magnet is energized, the armature automatithe latter is deenergized, means acting on the fingers for causing the same to then disengage their contact posts in consecutive and timespaced order and means for retarding the automatic movement of the. armature only after the contact-"fingerlfirstacted or has been disengaged from; its contact post;

2. A switch structure including a fixed electromagnet, an armature movable to and from the same, a pair of independent contact fingers mounted in connection with the armature, fixed contact posts with'which said fingers respectively engage when" the magnet is energized, the armature automatically movin away from the magnet whenthe lat-' ter is eener i zed, means acting on the fingers for causing the same to then disengage their posts in consecutlve order, and ad ustment means for enabling the time between sucii consecutive movement to be altered at wil 3. A switch structure including a fixed electromagnet, an armature movable to and from the same, a pair of independent contact fingers mounted in connection with the armature, fixed contact posts with which said fingers respectively engage when the magnet is energized, the armature automatically moving Laway from the magnet when the latter is deenergized, means acting on the fingers for causing the same to thendisengage their contact posts in consecutive order, a dashpot structure for retarding the automatic movement of the armature, and means between the armature and said structure for enabling the armature to move without being influenced by the dashpot until the contact finger first acted on has been disengaged from its contact post.

4. A switch structure including a fixed electromagnet, an armature pivoted with respect to the magnet for movement to and from the same, a pairof independent contact fingers mounted in connection with the armature, fixed contact posts with which said fingers respectively engage when the magnet is energized, said armature automatically moving'away from the magnet when the latter is deenergized, means acting on the fingers for causing the same to then dis-' engage their contact posts in consecutive order, a dashpot structure for retarding the automatic movement of the armature,a lever pivoted intermediate its ends and connected at one end to the dashpot; the opposite end of the lever being movable in a plane substantially at right angles to the plane of movement of the armature and its opposite end having a slot disposed at right angles to the longitudinal plane of the lever, and a member provided with the armature and projecting into the slot; said member and slot vbeing so arranged that when the armature is engaged with the magnet the member is.

5. A switch structure including a fixed electromagnet, an armature movable to and from the same, a pair of independent contact fingers mounted in connection with the armature, fixed contact members with which said fingers respectively engage when' the magnet is energized, the armature automatically moving away from the magnet when the latter is deenergized, means for causing the finger first engaged with its post to be disengaged therefrom with a quick break as soon as the magnet is deenergized, other means for retarding the movement of the armature only after said quick break has taken place, and .means maintaining the other finger engaged with its contact post during an adjustable period of such retarded movement. i

6. A structure as in claim 3, in which said last named means includes a movable arm mounted in connection with the dashpot structure and having a transverse slot therein and a pin mounted in connection with the armature and projecting into the slot; the

pin being so disposed that it will engage one end of the slot and cause the arm to move only after the armature has moved away from the magnet a certain distance.

7. A switch structure including a fixed electromagnet, an armaturemovable to and from the same, a panel mounted on the armature, a contact finger bearing at one end against the face of the panel and projecting beyond the same, a fixed contact member to be engaged by the finger when the armature is engaged by the magnet, the fin er beyond its end engaging the panel being then spaced from the panel, an adjustable screw mounted IRA SMITH.

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