USRE20676E - Electric switch - Google Patents

Description

Much 22, 19.38, GQO, MLMS ET AL Re. 20,676

ELECTRIC swrrcu Original Filed July 11, 1935 2 Sheets-Sheet 1 Hans .Felprsan Reiseued Mar. 22, 1938 I morale swrrcn aim was, Milwaukee, and Hans Petersen, Wauwaton. Bradley ration of Wisconsin Wis., assignors to Allen- Company, Milwaukee, a corpo- Original No. 2,011,149, dated February 16. 1931,

Serial No. 30,790,

Jilly 11, 1935. Divided and application January 8, 1937, Serial No.

Patent No. 2,090,170, dated August 1'1, 1937. Application for reissue February 9, 1938, Serial No. -189,471 i c (or. 260-104) This invention relates to improvements in electric switches and refers more particularly to electromagnetically actuated control switches of the type shown in Reissue Patent No. 20,094, issued to Gustav O. Wilm's, et al., September 1, i936 and is a division of application, Serial No. 30,790, flled July 11, 1935, now Patent No. 2,071,149, February 16, 1937.

As in the patent above noted. the switch 01 this invention is of the solenoid type wherein the movable contacts. have a straight line motion to and from engagement with their respective stationary contacts, but' in this instance all of the contacts are enclosed within a novel insulated arc enclosing chamber .so constructed that while it completely encloses the contacts, access forinspectionand replacement of contacts are readily had. The movable contacts are actuated from the exterior of the enclosure by a solenoid type electromagnet.

Thisiin'vention has as a general object to improve the construction of switches of this character and to provide a stronger and simpler manner of assembling the component parts of the switch. I

More specifically it is an object of this invention to provide a switch which is so constructed that alignment between the stationary and movable contacts is assured automatically upon assembly of the component parts of the switch, and which is self-insulating so that it may be mounted directly on a machinepart.

A further object of this invention is to provide a rigid and strong mounting means forthe switch structure and accompanying devices and to make the whole assembly universal for mounting purposes in that no additional insulation is necessary.

Still a further object'of this invention is to provide a rigid and universal mounting means for switches at a reduction in cost, material, weight,

and labor.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appendedclaims, it being understood that such changes in the precise embodiment of the, hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

Flgurel is a front view of a switch embodying this invention, parts thereof being broken away and in section;

Figure 2 is a sectional view of the switch, through Figure 3 on the plane of the line 2-2 showing particularly the arc enclosing chamber properly assembled;

Figure 3 is 'a longitudinal sectional .view through Figure 1 on the plane of the line 33.

Referring now particularly to the accompanying drawings in which like numeralsindicate like parts throughout the several views, the numeral 5 designates a flat sheet metal panel or backing plate upon which the switch mechanism, indicated generally by the numeral 6, and its actuating electromagnet 1 are mounted. The switch mechanism comprises a plurality of pairs of stationary contacts 8 adapted to be electrically bridged by movable contact units 9 actuated in a straight line motion by the electromagnet.

The electromagnet I has a laminated field piece III which is rigidly mounted on the panel 5 by means of a bracket ii. The field piece it has substantially an inverted U-shape and has an armature II slidably received between its legs, the lower ends of which are directed inwardly toward each other to lie close to the armature.

Within the hollow of the field piece is a coil i3 readily detachably held in place by channelshaped guideways II in which the armature slides.

The poles of the; field piece are provided by downwardly extending projections iii on which shading coils ii are mounted in the customary manner.

The armature i2 is of inverted T-shape with its stem or shank slidable in the guideways II and its head projecting to opposite sides for coaction with the poles i6. Like the field piece, the armature is of laminated construction. A central lamination I8 is formed of nonmagnetic metal and slidably projects through an opening I! in the top of the field piece.

Attached to the projecting upper end portion 01' the lamination i8 is a contact carrier 20. This carrier 20, which is fastened to the lamination l8 by a screw 2i, comprises a bar of molded insulating material with a metal insert 22 providing a reinforcing rib therefor. The front of, ,the molded cross bar has a recess 23 to expose the adjacent central part of the metal reinforcing rib 22 so that the lamination I8 is engageable directly therewith.

ga'g'ement with the panel by a screw 81 passed' no part of this invention, and therefore will not be described. For a' detailed description thereof reference may be had to the aforementioned application ofwhich this is'a division. It is desired to note, however, that each contact unit comprisesa contact bar 25 equipped with contacts .25 of a silver-cadmium alloy electro-welded to its end portions, and that the bar is resiliently supported from the carrier 20, the resilient mounting incorporating a telescoped spring 'en'- closure 21.

The stationary contacts 8 are fixed to the top wall 28 of an arc enclosing or are suppressing chamber, indicated generally by the numeral'28.

This chamber differs from archoods of the past in that it is totally enclosed and provides a complete enclosure for the conta cts. It consists of three. separable interengaging sections. a base or rear section 88, the top wall 28, and a cover or front section II- The base or rear section ill-comprises a rear' wall 32, side walls 88, and a bottom wall 88, the rear wall 32 projecting down beneath the bottom wall. 1

The rear wall 82 has two spaced square openings to snugly receive mounting posts 38 riveted .or otherwise fixed to-the metal panel 5., The base section is held on the posts 36 in flat enthrough the downwardly projecting part ofthe rear wall and threaded into the panel 5.

The rear and side walls .32 and -33, respectively, of the base section have connecting grooves 38 and 38, respectively, formed in their inner faces v to snugly receive the adjacent edgeportions of the upper section ofthe arc enclosing chamber comprising'thertop wall 28. The top wall 28 is thus slidably engageable with'the base or rear section from the front of the switch.

This top wall 28 has two downwardly projecting,webs 40 which provide partition walls to divide. the interior of the arc enclosing or arc suppressing chamber into three separated compartments. Obviously; each pair of stationary contacts 8 is disposed'in one of the compartnients thus formed and likewise; the cooperating movablecontacts move in these separated compartments for coaction with the stationary contacts- The stationary contacts, like the movable contacts, areformed of a silver cadmium alloy and are electro-welded onto the heads of copper bolts 4|, the stems of which project through and above .thetop wall to also mount "terminals 42. The top 'wall 28 thus'not only provides one wall of the arc hood, but also-serves as aterminal head to which the stationary contacts and their terminals are secured, and it is to be noted that the terminals for the contacts are offset with respectgto each other so that all of them are" central rib with the fwalls 38 bottom wall 5| of conductor wires chamber the engagement between the ends of 'this central rib and the front edges, of the side walls 83 permits the top wall to-move all the -way back, but if the top wall isinserted in rewith its front edge -i'earversed position, i. e., ward, the engagement of the extremities of the front edges of the side will preclude complete and proper assembly. of the top wall with the base or rear section, and, as

preclude the application of,the cover or front section; thus clearly indicating that the top wall has been improperlyapplied.

:The webs 48, which serve as the partitions beh tween the respective contact compartments;a--'are longitudinally channeled as at M to snugiy receive and embrace the mounting posts 85. In so embracing the posts, the webs or partitiomwalls afl'ord adequate insulation for the posts .and

preclude the possibility of arcing between the 2 contacts and the grounded posts. Both ends of the webs {0 are also channeled to formspaced flanges 45 which engage in complementary grooves in the rear wall of the rear or base section and similar, grooves or recesses in the front wall 48 lower edges of the two webs or partitions have sliding engagement with ,grooves in the bottom base section and in the wall 3| of 'the rear or of the cover or front section.

Consequently, the partition walls which divide the arc hood into separated compartments have a tongue and groove interengagement with both the rear or base section and the front or cover section so as to provide an effective seal be- .tween the respective compartments. This inter-' engaging tongue and groove joint ,between the engaging portions of the different sections provides overlapping surfaces of sufficient area to form 'a tortuous leakage. path long enough to cool an arc or hot gases escaping from one compartment into the other so that the possibility of arcing between the difierent poles of the switch is reduced to a minimum.

As already noted, the front or cover section 3| is similar in many respects to the rear or base section. It provides the front wall 48 of the arc hood and its bottom wall 5| meets with the bottom wall 34 of the rear or basersection to complete the bottom for the arc hood. The side walls 52 of the cover section coact with the side walls 33 of the base "section to complete the side walls oflthe arc hood and like the. rear or base section, the inner faces of the front and side walls have continuous and connecting grooves 53 and 53" to slidably receive portions of the top wall 28.

the adjacent edge Toaccommodate "the extremities of the longitudinal rib on the 1' recesses 5| above top wall, the side walls 52 have andcommunicatingwith the grooves 53', these recesses being of a size to just receive the extremities of the longitudinal rib when the top wall is properlyassembled but to prevent com plete application of the cover when the top wall is improperly mounted. V

There is also an interengaging overlapped joint between the abutting edges of the side walls of the front and rear sections, as shown.

.Holes in. the front wall. receive the threaded outer ends'of the posts 38 so that by means of nuts 56 threaded on the posts, the three sections comprising the arc hood are held assembled. Obviously, it is only necessary to remove the nuts 56 to tion when it is desired to expose the contacts for will b'e hereinafter described, will 1 of the cover or front section 3|; and the permit withdrawal of the cover see inspection and if a new set of stationary contacts is necessary, the entire top wall may be replaced so that the substitution of contacts is an extremely simple matter. 1

The bottom wall of the arc hood, which is formed jointly by the bottom walls 34 and ii of the base and cover sections, respectively, has three holes 51 formed half in the base section and half in the cover section, as illustrated. These holes lead to the separated arc suppressing compartments and are of a size to slidably receive the telescoped spring enclosures 21 with just suflicient clearance for free sliding action. In other words, the telescoped spring enclosures 21 substantially close the holes 51 so that while the movable contacts are actuatable from without the arc suppressing chamber, the completeness of the enclosure aflorded thereby is not destroyed to the point of interfering with the confinement of the arc, but it is to be observed that the clearance between the spring enclosures and the walls of the holes is sufflcient to facilitate or enable rapid venting of accumulated gases from within the chamber.

In operation, when the electromagnet is energized, the armature is drawn up in a straight line to impart a straight line motion to the contact carrier which lifts all of the movable contacts simultaneously from their switch open positions to which they move by gravity into switch closing positions with each contact arm electrically bridg ing its respective pair of stationary'contacts.

Upon deenergization of the electromagnet, the movable contact unit drops to an open position thus simultaneously disengaging all of the movable contacts from their respective stationary contacts and breaking each line at two places.

The are which tends to form upon opening of the switch is suppressed and quickly and effectually extinguished.

While it is not positively known just what produces the exceptional arc extinction obtained with this switch, tests indicate that it must be the combined effect of a number of structural.

features. Possibly the most important element in the chain of causation is the close confinement of the arcs by the enclosure of the contacts within an insulating chamber of restricted volume resulting inter alia in the development of high pressure within the chamber. This, together with the fact that the arcs are positively and forcibly projected in opposite directions away from each other and against opposite walls of the chamber by reason of the relative positions of the stationary contacts and bridging barand the conductors leading to the contacts, plus the deionizing eil'ect which the silver cadmium alloy of the contacts has upon the closely confined arcs, and

.the fact that the clearance between the spring enclosures and the holes 51 through which the spring assemblies enter the chamber compartments, facilitates the escape or enables venting of the accumulated gases from the interior of the chamber without delay after extinction of the are so that the chamber is cleared of any deleterious and objectionable gases to make it ready for a closely following cycle, possibly explains how this desirable arc quenching or suppressing eflect is obtained.

Stated briefly, it is thought to be the close conflnement oi the arc to produce a suppressing pressure, cooling of the are by contact with closely adjacent wall surfaces. the deionizing effect of the metal of which the contacts are composed and the rapid venting of the accumulated gases afterextlnction of the are which brings the desired results.

The cooling eflect mentioned is augmented by shallow cavities 60 in the walls which the arcs impinge. From the foregoing description taken in connection with the accompanying drawings, it will be readily apparent to those skilled in the art, that this invention provides a substantial improvement in the construction and design of plunger type electric switches and that by reason of the novel are enclosing chamber flash-over between the poles of the switch is effectually prevented and as a consequence, instantaneous rupturing of the arc is practically assured and the interrupting capacity of the ,switch is materially increased. 7

It will be also apparent that the inherent design of the switch of this invention makes the same self-insulating so that-it may be mounted on any non-insulating support. This very highly desirable feature is the direct result of the particular construction of the arc suppressing chamber in that all live parts of the switch are either carried directly by or enclosed within this chamber which being'formed of a .good insulating material provides all the insulation for the switch and thus entirely obviates the need for slate or other insulating panels. 1

What we claim as ourinvention is:

1. In an electric switch for industrial control service having stationary and movable contacts and terminals for the stationary contacts: a metallic mounting plate an insulating contact enclosure closed on all sides except for an entrance opening and having the stationary contacts and their terminals-mounted thereon with the stationary contacts on the inside and the terminals on the outside of the enclosure, the movable contact Being disposed within the enclosure so that an are drawn between the contacts upon separation thereof is confined to the interior of said enclosure; means mounting the enclosure directly on the metallic plate so that the stationary contacts are secured in fixed relation to' the plate but insulated therefrom; an electromagnet mounted on said plate and having an armature; and a driving connection between the armature and the movable contact witha part thereof passing through the entrance opening.

2. In an electric switch: cooperating stationary and movable contacts; a metal back plate; a hol-' low structure of molded insulating material enclosing the contacts and having the stationary contacts rigidly attached thereto; means rigidly securing said hollow structure directly to the back plate in frontwise removable relation, said securement of the hollow structure to the base plate securing the stationary contacts in definite relationship to theback plate while the contacts and an arc drawn therebetween upon opening of the switch are completely insulated from the back plate; an automatic actuating means rigidly mounted on-the back plate so as to have tlxed alignment with the contacts; and a driving connection between said automatic actuating means and the movable contacts passing through an opening in one" wall of the hollow structure.

3. In an electric switch: pairs of stationary contacts; a movable contact for each pair of stationary contacts adapted to electrically bridge the same; a metal base plate adapted to be mounted in a vertical position; an insulating enclosure fixed to the baseplate and enclosing the contacts,

4 g said enclosure comprising a base section secured to the metal base, a top section,.and a i'ront section; connections between the sections so; formed 7/ that securement of the front section in position holds the top section against displacement and said connection enabling removal otthe'i'i-ont section to afl'o'rd access to the interior of the-enclosure without disturbing the top section; an electromagnet mounted on 'said base plate and 10 having an armature, a connection between the armature and the movable contacts so-that the armature moves the; movable contacts in a substantially vertical line; and terminals for the staf tlonary contacts, said terminals and the stationary contacts being mounted on the top section of the enclosure with the terminals on. the exterior projecting upwardly away from the contacts.

4. In an electric switch for industrial control service having stationary and movable contacts 20, and terminals for the stationary contacts: a metallic mounting plate; "an insulating contact enclosure having 'an entrance opening and having the stationary contacts and their terminals mounted thereon with the stationary contacts on 25 the inside and the terminals on the outside of the enclosure, the movable contact being disposed within the enclosure so that an are drawn between the contacts upon separation thereof is substantially confined tothe interior of said enclosure; means mounting the enclosure directly on the metallic plate so that the stationary contacts are secured in fixed relation to the plate but insulated therefrom; an electromagnet mounted on said plate and having an armature; and a driv- 35 ing connection between the armature and the movable contact with a part thereof passing through the entrance opening.

5. In an electric switch: pairs of stationary Re. 20,676.Gustav 0. Wilma,

ELEc'rarc SWITCH. Patent dated M 1948, by the assignee,

[Ofiicial Gazette January 11, 1 949.]

, fixed to 'the base plate Allen-Bradley' Hereby enters this disclaimer to claims 1,

contacts; a movable contact for each pair or st a' 'tionary "contacts adapted to electrically bridge the same; a metal base plate adapted to be mountan insulating enclosure and enclosing'the COD-9 tacts, said enclosure having an entrance opening and being sectional withoneoi' its sections constituting a front section adapted for Irontwise removal to provide quick access to the contacts;

ed in\ averti c-al position an electromagnetmountedon said base plate and having an armature; and .a connection between the armature and the ing a part passing through the entrance opening and movable in a substantially straight line to carry the movable contacts to "and from engagement with the stationary contacts in a substantially straight line motion.

,6. In an electric switch: a plurality of independently mountable unitary structures; one of said structures comprising closure of insulating material having an entrance openingand cooperative stationary and movable contacts therein; another of said structures comprising movable contact actuating means; a metallic support; means for mounting said structures on the support so that. the metallic support affords operative alignment-of said structures; said entrance opening in the, enclosure being formed by the adjacent edge walls of two of the sections thereof, a driving connection between said actuating means and the movable contacts with a part thereof passing through the entrance opening; and one or said wall forming sections being frontwise removable with respect to-said support, whereby ready access may be had to the contacts.-

GUSTAV o. wILMs. HANS PE'I'ERSEN.

Disclaimer Milwaukeeyand Hans Petersen, Wauwatosa,

ar. 22, 1938. Disclaimer filediDec. 13;

2, 4, 5, and 6 in said specification.

movable contacts includa sectional hollow en 4 g said enclosure comprising a base section secured to the metal base, a top section,.and a i'ront section; connections between the sections so; formed 7/ that securement of the front section in position holds the top section against displacement and said connection enabling removal otthe'i'i-ont section to afl'o'rd access to the interior of the-enclosure without disturbing the top section; an electromagnet mounted on 'said base plate and 10 having an armature, a connection between the armature and the movable contacts so-that the armature moves the; movable contacts in a substantially vertical line; and terminals for the staf tlonary contacts, said terminals and the stationary contacts being mounted on the top section of the enclosure with the terminals on. the exterior projecting upwardly away from the contacts.

4. In an electric switch for industrial control service having stationary and movable contacts 20, and terminals for the stationary contacts: a metallic mounting plate; "an insulating contact enclosure having 'an entrance opening and having the stationary contacts and their terminals mounted thereon with the stationary contacts on 25 the inside and the terminals on the outside of the enclosure, the movable contact being disposed within the enclosure so that an are drawn between the contacts upon separation thereof is substantially confined tothe interior of said enclosure; means mounting the enclosure directly on the metallic plate so that the stationary contacts are secured in fixed relation to the plate but insulated therefrom; an electromagnet mounted on said plate and having an armature; and a driv- 35 ing connection between the armature and the movable contact with a part thereof passing through the entrance opening.

5. In an electric switch: pairs of stationary Re. 20,676.Gustav 0. Wilma,

ELEc'rarc SWITCH. Patent dated M 1948, by the assignee,

[Ofiicial Gazette January 11, 1 949.]

, fixed to 'the base plate Allen-Bradley' Hereby enters this disclaimer to claims 1,

contacts; a movable contact for each pair or st a' 'tionary "contacts adapted to electrically bridge the same; a metal base plate adapted to be mountan insulating enclosure and enclosing'the COD-9 tacts, said enclosure having an entrance opening and being sectional withoneoi' its sections constituting a front section adapted for Irontwise removal to provide quick access to the contacts;

ed in\ averti c-al position an electromagnetmountedon said base plate and having an armature; and .a connection between the armature and the ing a part passing through the entrance opening and movable in a substantially straight line to carry the movable contacts to "and from engagement with the stationary contacts in a substantially straight line motion.

,6. In an electric switch: a plurality of independently mountable unitary structures; one of said structures comprising closure of insulating material having an entrance openingand cooperative stationary and movable contacts therein; another of said structures comprising movable contact actuating means; a metallic support; means for mounting said structures on the support so that. the metallic support affords operative alignment-of said structures; said entrance opening in the, enclosure being formed by the adjacent edge walls of two of the sections thereof, a driving connection between said actuating means and the movable contacts with a part thereof passing through the entrance opening; and one or said wall forming sections being frontwise removable with respect to-said support, whereby ready access may be had to the contacts.-

GUSTAV o. wILMs. HANS PE'I'ERSEN.

Disclaimer Milwaukeeyand Hans Petersen, Wauwatosa,

ar. 22, 1938. Disclaimer filediDec. 13;

2, 4, 5, and 6 in said specification.

movable contacts includa sectional hollow en

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