US3177331A - Electromagnetic switch - Google Patents

Description

April 6, 1965 MASAYOSIHI KAWABATA ETAL 3,

ELECTROMAGNETI C SWI TCH Filed Oct. 23, 1961 3 Sheets-Sheet l fl p; J4 59434 7a s 15a April 1965 MASAYOSHI KAWABATA ETAL 3,177,331

ELECTROMAGNETIC SWITCH Filed Oct. 25, 1961 3 Sheets-Sheet 2 A ril 6, 1965 MASAYOSHI KAWABATA ETAL 3,177,331

ELECTROMAGNETIC SWITCH Filed Oct. 23, 1961 3 Sheets-Sheet 3 F g; 8% a;

United States Patent Claims. (Cl. 200-168) This invention relates to electromagnetic switches and more particularly to a new and improved type of dustproof construction for electromagnetic contactors.

In a conventional electromagnetic switch of the type wherein a coil and stationary iron core are contained within the base structure of the electromagnetic switch, and the moving iron core and moving contact support are contained in a freely slidable manner within a stationary contact support mounted on the basic structure, the plurality of moving contacts which are arranged in a row on the moving contact support are disposed opposite the stationary contacts at recessed window portions on both sides of the stationary contact support. Consequently, such a conventional electromagnetic switch has had the disadvantage of accumulation and adhesion of dust on the contacting members, whereby satisfactory contacting condition could not be obtained. For this reason, such electromagnetic switches have heretofore been rendered dustproof by enclosing the entire structure within a housing made of transparent plastics or steel sheet. Such a measure has been uneconomical.

It is an object of the present invention to provide a new and simple type of dustproof construction for electromagnetic switches of this type.

The manner in which the foregoing objects and other objects of this invention may best be achieved will be more clearly apparent by reference to the following detailed description when taken in conjunction with the accompanying illustrations in which the same and equivalent parts are designated by the same reference numerals or letters, and in which:

FIG. 1 is a plan view of one representative embodiment of the present invention;

FIG. 2 is a side elevational view of the embodiment shown in FIG. 1;

FIG. 3 is a front elevational view, partly in section, in a direction perpendicular to that of FIG. 2;

FIG. 4 is a plan view of a transparent cover used in the embodiment shown in FIGS. 1, 2, and 3;

FIG. 5 is a plan view showing another embodiment of the presentinvention; I 1

FIG. 6 is a front elevational view, in section taken along the line VI-VI of FIG. 5;

FIG. 7 is an exploded, perspective view showing the principal parts of the embodiment shown in FIGS. 5

and 6;

FIG. 8 is a plan view showing yet another embodiment of the present invention;

FIG. 9 is a side elevational View of the embodiment shown in FIG. 8;

FIG. 10 is an exploded, elevational view of the embodiment shown in FIGS. 8 and 9, showing its state wherein the upper stationary contact assembly and dustproofing structure 1, in which a stationary iron core 2 and a coil 3 are enclosed; a lower stationary contact support 4, in which a moving iron core 5 and a moving contact support 6 are enclosed in a freely slidable manner; and an upper stationary contact support 7. The foregoing three essential parts are held rigidly together as a single body by assembly screws 8 and 8a. The upper stationary contact support 7 supports upper stationary contacts 9 in a row; and the lower stationary contact support 4 supports lower stationary contacts 10 also in a row. Window portions 11 are provided in aligned disposition on the two sides of the said upper and lower stationary contact supports. The upper and lower stationary contacts 9 and 10 are separated by means of partition walls 4a and 7a formed on both sides of the respective contact supports 4 and '7. Moving contacts 12 are disposed in the said window portions 11 and are confronted above and below by the stationary contacts 9 and 10. The window portions 11 on each side are covered and sealed completely by a transparent cover 13 and 13a, which are held tightly in place by elastic clamp members 15 and 15a having bent ends 16 and 16a which fit, respectively, into holes 14 and 14a cut out in the cover 13 and 13a. The transparent covers 13 and 13a are provided respectively with engaging recesses 13' and 13a at their upper portions confronting the partition walls 4a formed on both sides of the lower contact support 4, and the lower ends of the projections 13" and 13a" defined by the recesses 13 and 13a project to the depthcontacting with the lower surface of the stationary contact 9. Furthermore, the upper inside portions of the transparent covers 13 and 13a are provided respectively with vertical slots 13' and 13a confronting the partition walls 7a formed on both sides of the upper stationary contact support 7, and the inward directed projections 13" and 13a" formed by the vertical slots 13 and 1311' are attached so as to be in contact with the outside surface of the upper stationary contact 10. The elastic clamp members 15 and 15a need not be rigidly fixed at their central portions by screws 8 and 8a as illus-' trated, but may be anchored in any other "suitable manner, for example, by fitting said clamp members 15 and 15a into slots.

As illustrated in FIGS. 1 to 4, since the partition walls of the contact supports are engaged with the engaging recess 13' and 13a'or vertical slots 13" and 13a of the transparent covers 13 and 13a, rightward and leftward movement of the transparent covers 13 and 13a is avoided. Furthermore, the lower ends of the projections 13" and 13a of the transparent covers 13 and 13a are in contact with the upper surface of the lower stationary contact 9 and the upper projections 13" andllSa are made so as to be in contact with the outside surface of the upper stationary contact 10, so that the window portions 11 is completely covered from both sides. Accordingly, even when the electromagnetic switch is mounted in any position entering of airborne dust through the Window portions is effectively precluded;

The above-described construction has an advantage in that, when the electromagnetic switch is to be disassembled, or when only the upper contacting parts are to be disassembled, the transparent covers can be easily removed by removing the elastic clamp. Furthermore, the abovedescr'ibed construction ailords an electromagnetic switch of simple dustproof form which enables observation, from the outside, of the condition of the contacting parts.

a,177,ss1

The above-described construction, however, does not provide protection and partitioning of the terminals on the lower row of terminals. If said protection and partitioning were to be provided by terminal partition walls formed onthe electromagneticswitch structure, their fabrication would be difiicult and entails a high cost since they would be required to protrude outwardly from the side of the contactor structure. 7

Effective protection'and partitioning of the aforesaid terminals can be provided in a simple manner by modifying the transparent covers 13 and 13a of the above-mentioned embodiment illustrated in FIGS. 1 through 4. The modified covers, which are illustrated in FIGS. 5 through 7 and are designated therein by the reference numeral 117, are provided on their outside surfaces with partition plates 19, 19, of suitable configuration formed integrally thereon and so disposed'as to be positioned in alignment with the partitions 4a to jointly therewith form upstanding partitions between the terminals 18, 18, of the lower row when the covers 17 are assembled in place. The transparent cover 17 is provided with engaging recess 17' at the upper portion confronting the partithe lower surface of the stationary contact 9. Furthermore, the upper inside portion of the transparent cover .37 is provided with vertical slots 17 confronting the partition walls 7a formed on both sides of the upper stationary contact support 7, and the inward projection 17' forrned'by the said vertical slots 17" are attached so as to be incontact with the outside surfaceuof the upper stationary contact 10%. The covers 17 may be held in place, for example by elastic clamp members and 15a anchored by screws 8 and 8a in exactlythe same manner as in the first embodiment illustrated in FIGS. 1 through 4.

Undercertain conditions, the means of holding the dust-proofing covers as described above, that is, such means as elastic clamp members or snap on clamps and screw anchoring, may be disadvantageous because of failure or breakage due to their exposed positions. 7

An embodiment of theinvention wherein the covers are held tightly in position without the use of such means as elastic clamping members is illustrated in FIGS. 8 through 12. The internal construction of the electromagnetic switch illustrated inFIGS. 8 through 12 is the same as that of thetelectromagnetic switch illustrated in FIGS, 1' through 4 except the manner of attaching the 1 covers 22 is different.

projection 22' defined by the said recesses 22' projects suficiently to contact the lower surface of the stationary contact 9' Furthermore, the upper inside portion of the, transparent cover, 22 is provided with vertical slots 22 confronting the partition walls b formed on-both sides of the upper stationarycontact support7, and the inward projections 22" formed by the vertical slots 22'" of the lower contact support 4, and the lower end of the are in contact with the outside surface of the upper sta-v tionary contactitl. Briefly stated, coversZZ are clamped Each cover 22 is provided at its two ends with'lugs 23, which are so formed as tofit into corresponding recesses 24 formed in thelower stationary contact support '0. During assembly of the support B and C, the dustproofing covers 22'are first placed in position'so that their lugs 23 fit into their respective recesses 24 in the support C; then the support B is placed thereon and screwed or otherwise fastened down so as to clamp the covers 22 between itself and the'lower support C.

The above-described construction affords positive and tight retention of the covers 22 sons to prevent them from rattling or from slipping off because of such effects as impacts and vibrations. Furthermorqthis construction affords easy and low-cost fabrication, facility in assembly and disassembly, and a functional, esthetic design.

While a few particular embodiments of the'present invention have been described, it will'be obvious that many changesv and modifications can be made in the above de-' scribed details without departing ,from' the nature and spirit of the invention, and it is to be understood that the invention is not to'be limited to the details'described herein except as set forth in the appended claims.

Whatis claimed is: i V

1. in a dust-proof'switch, a base structure, an upper stationary contact support and a lower stationary contact support mounted on said base structure,van array of upper stationary contacts'and an array. oflower stationary contacts mounted respectively onsaid upper, and lower supportspextending along a length of, said switch means on said base structure mounting movable contacts for electrical connection with respective ones; of said stationary contacts, electromagnetic means housed in said base structure for actuating said movable'contacts, arrays of upper terminals for connection to said upper stationary contacts and an array of lowerterminals for connection to said lower stationary contacts disposed along a side'of the switch the improvement which comprises dust-proof covers means comprising. said upper support having partitions extending between the upper terminals, said lower support having partitions extending between the lower terminals, a transparent cover piecerhaving slots for recerving the partitions onsaid upper support and spaced recesses for receiving the partitions on'said lower support and extending along-a part of said side of the switch completely enclosing and defining a dust-proofspace with said supports and base structure in jWhlCh said movable and stationary contacts areivisible from externally of the switch for viewing theoperation thereof. 7

2. In a dust-proof switch according to claim 1, including a snap-onresilient clampholding the dust cover-piece in position. v

3. in a dust-proof switch according to claim 2 including at least one screw holdingtsaid upper support on said base and passing through said clamp. i

4. he dust-proof switch, a base structure,

support mounted on said base structure, an array of upper stationary contacts and an array of lower stationary con tacts mounted respectively on said upper and lower supports extending along a lengthvof said switch, means on switch, the improvement which comprises dustproof covers meanscornprising said upper supporthaving parti- V tions extending between-the upper terminals, said lower v support having-partitions between the lower'terrninals, two transparent cover-pieces having slots for receiving the partitions on said upper support and spaced. recesses-for receiving the partitions on said lower support and err-- 'tendingalonga part of. both said sides of the switch completely enclosing-and defining two dust-proof spaces with said supports and base structure in which said :movable and stationary contacts are visible: from externally of the an upper stationary contact-support and a-lower stationary contact switch for viewing the operation thereof, and each coverpiece having projections extending laterally therefrom and each disposed between each two successive ones of said lower terminals substantially in registry with said partitions on said lower support and each configured to jointly with the last mentioned partitions define upstanding partitions between said lower terminals.

5. In a dust-proof switch according to claim 4, includ ing a snap-on resilient clamp clamping both said side cover-pieces and biasing them toward each other.

References Cited in the file of this patent UNITED STATES PATENTS Irwin July 29, 1941 Knapp Dec. 13, 1949 Toth et a1 Dec. 20, 1955 Reichert et a1 Dec. 20, 1955 Droel June 30, 1959 Brunicardi July 21, 1959

Claims (1)

1. IN A DUST-PROOF SWITCH, A BASE STRUCTURE, AN UPPER STATIONARY CONTACT SUPPORT AND A LOWER STATIONARY CONTACT SUPPORT MOUNTED ON SAID BASE STRUCTURE, AN ARRAY OF UPPER STATIONARY CONTACTS AND AN ARRAY OF LOWER STATIONARY CONTACTS MOUNTED RESPECTIVELY ON SAID UPPER AND LOWER SUPPORT EXTENDING ALONG A LENGTH OF SAID SWITCH MEANS ON SAID BASE STRUCTURE MOUNTING MOVABLE CONTACTS FOR ELECTRICAL CONNECTION WITH RESPECT ONES OF SAID STATIONARY CONTACTS, ELECTROMAGNETIC MEANS HOUSED IN SAID BASE STRUCTURE FOR ACTUATING SAID MOVABLE CONTACTS, ARRAYS OF UPPER TERMINALS FOR CONNECTION TO SAID UPPER STATIONARY CONTACTS AND AN ARRAY OF LOWER TERMINALS FOR CONNECTION TO SAID LOWER STATIONARY CONTACTSDISPOSED ALONG A SIDE OF THE SWITCH THE IMPROVEMENT WHICH COMPRISES DUST-PROOF COVERS MEANS COMPRISING SAID UPPER SUPPORT HAVING PARTITIONS EXTENDING BETWEEN THE UPPER TERMINALS THE LOWER SUPPORT HAVING PARTITIONS EXTENDING BETWEEN THE LOWER TERMINALS, A TRANSPARENT COVER-PIECE HAVING SLOTS FOR RECEIVING THE PARTITIONS ON SAID UPPER SUPPORT AND SPACED RECESSES FOR RECEIVING THE PARTITIONS ON SAID LOWER SUPPORT AND EXTENDING ALONG A PART OF SAID SIDE OF THE SWITCH COMPLETELY ENCLOSING AND DEFINING A DUST-PROOF SPACE WITH SAID SUPPORTS AND BASE STRUCTURE IN WHICH SAID MOVABLE AND STATIONARY CONTACTS ARE VISIBLE FOR EXTERNALLY OF THE SWITCH FOR VIEWING THE OPERATION THEREOF.

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