US3243545A - Two-way cushion for contactor - Google Patents

Description

March 29, 1966 E. T. PLATZ E TAL Two-WAY CUSHION FOR CONTACTOR Filed May 24, 1963 5 Sheets-Sheet 1 K x m? mm m a: e 4

March 29, 1966 PLATZ ETAL 3,243,545

TWO-WAY CUSHION FOR CONTACTOR Filed May 24, 1963 5 Sheets-Sheet 2 Mardl 6 E. T. PLATZ ETAL 3,243,545

TWO-WAY CUSHION FOR CONTACTOR Filed May 24, 1963 5 Sheets-Sheet 5 United States Patent 3,243,545 TWO-WAY CUSHION FOR CONTACTOR Elwood T. Platz, Grosse Pointe Farms, and Andrew J.

Kralik, Detroit, Mich., assignors to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed May 24, 1963, Ser. No. 283,084

9 Claims. (Cl. 20087) This invention relates to contactors in general and more particularly to an improved means for absorbing shocks which are generated when the contactor magnet is energized.

In the Cataldo et al. copending application Serial No. 189,915, filed April 24, 1962, entitled Electrical Device," and assigned to the assignee of the instant invention, there is disclosed a contactor of the type to which the instant invention is applicable. Briefly, the contactor is a multiphase unit having two stationary contacts and a movable bridging contact for each phase. The bridging contacts of all phases are operatively connected to the armature of an electromagnet. The magnet yoke is positioned by 'a cushion mounting so that the shocks which are generated upon the engagement of the armature with the magnet will minimize damage.

It is not only the direct impact of the armature engag ing the yoke which must be absorbed but there is also a rebound shock which must be absorbed. Some prior art constructions attempt to absorb both the direct and rebound shocks by utilizing a single spring member. This has proven to be less than satisfactory since the shock absorbing means must be tied to the same means which positions the yoke relative to the armature for the deenergized condition of the electromagnet. It is essential that the air gap between the two magnetic core members be accurately controlled and that this gap not vary appreciably when the contactor is subjected to external shock forces. By utilizing a single shock absorbing memher in an efiort to accomplish both direct and rebound shock absorption it is necessary to resort to compromises and as a result it is necessary to settle for less than top a performance.

The instant invention overcomes this difficulty of the prior art by providing a construction in which one spring means is utilized for the absorption of direct shocks while another spring means is utilized for the absorption of rebound shocks. The construction is such that upon rebound contact separation or lift-off is substantially prevented so that arcing, hence contact erosion, is minimized. Further, the magnet yoke is not rigidly tied to the stationary base so that the former is not tied to a large encumbering mass. The yoke is relatively free to recoil under the shock of closing thereby reducing distortion and wear at the pole faces.

In some of the embodiments to be hereinafter described, means are also provided for adjusting the yoke relative to the armature so that air gap length may be accurately controlled. Not only are the shock absorbing abilities of the device of the instant invention vastly superior to those of similar prior art devices, but in addition the shock absorbing means is so constructed that assembly of the contactor is facilitated.

Accordingly, a primary object of this invention is to provide a novel shock absorbing means for an electromagnetic contactor.

Another object is to provide a shock absorbing means of this type having a novel construction in which a means is provided for the absorption of direct shocks and a separate means is provided for the absorption of rebound shocks.

Still another object is to provide a novel means for mounting the magnet yoke of a contactor such that the 3,243,545 Patented Mar. 29, 1966 adverse effects of armature impact on contact life and pole face conformation will be minimized.

A further object is to provide a cushioning means of this type having means for adjusting air gap length between the armature and yoke for the deenergized condition of the electromag'net.

These as well as further objects of this invention shall become readily apparent after reading the following description of the accompanying drwings in which:

FIGURE 1 is an exploded perspective of the main elements of a contactor incorporating the novel shock absorbing means constituting the instant invention.

FIGURE 2 is a load side view of the contactor base with the magnet yoke and retaining elements mounted thereto.

FIGURE 3 is a plan view of the contactor base with the magnet yoke and retaining elements mounted thereto.

FIGURE 4 is an exploded perspective of the magnet yoke and the shock absorbing elements.

FIGURE 5 is a fragmentary view partially sectioned t0 illustrated another embodiment of the invention in which two elements are provided for adjusting the air gap length between the leg and armature for the deenergized condition of the electromagnet.

FIGURE 6 is a view similar to FIGURE 5 illustrating a third embodiment of the instant invention.

Now referring more particularly to FIGURES 1 through 4. Contactor 10 is a multiphase unit 'of the type described in detail in the aforesaid copending application 189,915. Each phase is provided with a bridging element 11 which is movable downward with respect to FIGURE 1 into engagement with a pair of stationary contacts 12a, 12b. All of the stationary contacts 12a, 12b are secured to plate 13 which is mounted in fixed position upon molded insulating base 14 with the latter being secured to mounting plate 15. It is noted that in operation plate 15 is positioned in a vertical plane so that all of the elements of the contactor are deemed to be mounted on the forward side of plate 15.

Each of the bridging contacts 11 is mounted at the forward end of a projection 16 extending forwardly from movable contact carrier 17. The latter is mounted to the rear of plate 13 being biased thereagainst by two coil springs 18, only one of which is shown in FIGURE 1. Studs 19 extend through coil springs 18 and clearance apertures in contact carrier 17, into plate 13, so as to constitute guides for the movement of carrier 17 relative to plate 18. Springs 18 are coiled compression elements with one end of each resting against the rear surface of carrier 17 and the other end resting against the enlarged head of stud 19. Plate 13 carries pivotally mounted clips 21 which removably secure cover 22 in operative position to cooperate with plate 13 in covering the contacts 11, 12a and 12b of all phases.

Secured to contact carrier 17, in a manner described in detail in the aforesaid copending application 189,915 is U-shaped armature -25 whose legs extend rearwardly. When the plate-contact carrier assembly 30 is mounted to base 14, the heads of studs 19 rest against fixed portions of base 14 so that plate 13 is fixed in relation to base 14. Screws secure stationary contacts 12a to line terminals 29 and other screws secure contacts 12b to load terminals 28.

Coil springs 18 position pole faces 25a and 25b a sembly 40 is provided with two contact buttons 39 which .engage spring contacts 38 mounted in base 14. It is noted that portions of the enlarged heads of studs 19 rest against the forward surface of coil assembly 40 to limit forward movement thereof.

Serpentine leaf spring 44 is interposed between base 14 and the rear surface of the yoke web 350, being disposed within base pocket 45 which receives the yoke web 35c. Yoke'35 is secured to base 14 by means of two sets of elements. Each of these sets comprise a plate 46 a coil spring 47, and a retainer 48.

Edge 46a of plate 46 extends into side recess 35d of yoke 35. It is noted that the height of recess 35d is considerably greater than the thickness of plate 46 so that a lost motion connection is formed between yoke 35 and plates 46. The arms 48a, 48b of U-shaped retainer 48 receive base formation 14a therebetween. Coil spring 47, disposed within recess 14b of base formation 14a, is a compression member one end of which bears against the forward boundary of recess 14b and the other end of which extends beyond the rear end of recess 14b and bears against retainer arm 48b.

Plate 46 is interposed between retainer arm 48a and surface 14c of base formation 14a. Retainer 48 is resiliently held in place by virtue of the fact that the outwardly extending wing tip of retainer arm- 48a are positioned inwardly of plate ears 46b.

As seen in FIGURE 2, when magnet coil assembly 40 'is deenergized serpentine spring 44 urges yoke 35 forwardly so that the rear boundary of yoke slot 35d engages plate edge 46a to establish the desired position for yoke 35 relative to base 14.

When coil assembly 40 is energized, the direct impact of armature 25 engaging yoke 35, yoke 35 moves to the rear and the shock is absorbed by serpentine spring 44. However, during this period certain rebound forces are generated due to the fact that spring 44 is being deformed, opening springs 18 are being compressed and the contact pressure springs (not shown) are also being compressed. Thus, a rebound force of considerable magnitude is built After the direct closing the shock is absorbed by serpentine spring 44, yoke 35, armature 25 and contact carrier 17 rebound as a unit. If plates 46 were not resiliently mounted the rebound shock would cause excessive damage. However, as yoke 35 moves forward the inward edge 46a of plate 46 also moves forward. This movement is permitted since retainer leg 48b rests against the rear end of spring 47 and is free to move at least as far as the surface 14d of base formation 14a. Prior to engagement the rebound forces have been expended.

Springs 47 are so constructed that their combined forces is slightly in excess of the normal steady combined forces of return springs 18, contact pressure springs (not shown) and thespring of any interlock device which may be connected to contactor 10.

In the embodiment of FIGURE the same serpentine spring 44 is utilized to absorb direct shocks. Plate 60 which extends into yoke recess 35 is maintained against base surface 61 by conical coiled compression spring 62 with the wide end of spring 62 hearing against plate 60 and the narrow end of spring 62 bearing against the head of retaining screw 63. Screw 63 extends through spring 62 and the base formation which includes surface 61 with the end of screw 63 remote from its head being engaged bynut 64 whose position determines the loading of spring 62. Nuts 65a and 66a are mounted within recesses of base 67 adjacent to surface 61 with these recesses being shaped so that nuts 65a, 66a are prevented from rotating. Threadably mounted to nuts 65a and 66a are adjusting screws 65 and 66, respectively.

Yoke 35 is moved forwardly by turning screw 66 so that it moves toward plate 60. Similarly, yoke 35 is moved rearwardly by turning screw 65 so that it moves forward. After all of the adjustments have been made, a, suitable sealer may be applied to assure thatthese adjustments will remain fixed.

In the embodiment of FIGURE 6 compression coil spring 71 disposed within a base recess engages the outer end 72a of plate 72 urging plate 72 forward into engagement with bracket 73 secured to the base by screw retainer 74. The inner end 725 of plate 72 extends into yoke recess 35d. The engagement of yoke 35 with plate 72 in its normal position of FIGURE 6 establishes the normal position for yoke 35 relative to the base. Adjustment of screw 74 determines the position of bracket 73, hence the position of plate 72.

As in the other embodiments serpentine spring 44 provides a cushion for direct shock. During rebound yoke 35 attempts to move forward. This causes the innerend 72b of plate 72 to move forward so that plate 72 pivots about bracket 73 at edge 73a with the outer end 72a of bracket 72 compressing spring 71.

Thus, this invention provides a novel construction for a shock absorbing means utilized with contactor magnets. The construction is such that individual spring elements are utilized for absorbing direct and rebound shock forces so that no compromises need be made. This results in minimizing the adverse effects of armature impact on con tact life and pole face conformation.

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appending 0 arms.

The embodiments of the invention in which an excluisive privilege or property is claimed are defined as folows:

1. A device for the class described comprising a set of cooperating contacts and an electromagnet operatively connected to said contacts for operation thereof; said electromagnet comprising a core and an energizing winding therefore; said core comprising a movable core member and a relatively stationary core member; means biasing said first core member away from said second core member; means mounting said first core member for movement in a first direction toward said second core member upon energization of said winding; first means supporting said second core member and constituting means for absorbing direct shock brought about by engagement of said second core member; second means .separate from said first means for normally limiting movement of said second core member in a second directron toward said first core member; said second means including a resilient portion operatively engaging said I second core member so as to yield to a limited extent as said second core member rebounds under the influence of said first means, said second means includes a plate, a spring, and a stop; said spring urging said plate against said stop; said plate extending into a recess in said second core member; said recess and said plate being so proportioned as to permit movement of said second core member relative to said stop.

2. The device of claim 1 in which the first means normally urges a portion defining said recess into engagement with said plate, said first means constructed to permit said portion to disengage said plate upon the occurrence of direct shocks.

3. The device of claim 2 in which said portion engages said plate as said second core member rebounds thereby causing said plate to move relative to said stop.

4. The device of claim 3 in which the second means also includes a U-shaped retainer having a first and a second leg; said spring engaging said first leg and urging said retainer in said first direction; said second leg being in engagement with said plate with said plate being interposed between said stop and said second leg.

5. The device of claim 2 in which the spring directly engages said plate; said stop being comprised of adjustable means whereby the position of the second core member relative to the first core member is adjustable to a desired position when said winding is deenergized.

6. The device of claim 5 in which said stop is comprised of screw means directly engaging said plate.

7. The device of claim 2 in which one end of the plate extends into the recess of the second core member and the spring directly engages the plate near the other end thereof.

8. The device of claim 7 in which stop includes an edge defining a pivot about which said plate is rockable during the process of absorbing rebound shocks.

9. The device of claim 8 in which the stop is adjustably mounted whereby the position of the second core 61, member relative to the first core member is adjustable to a desired position when said winding is deenergized.

References Cited by the Examiner UNITED STATES PATENTS 584,050 1/ 1947 Great Britain.

BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

B. DOBECK, Assistant Examiner.

Claims (1)

1. A DEVICE FOR THE CLASS DESCRIBED COMPRISING A SET OF COOPERATING CONTACTS AND AN ELECTROMAGNET OPERATIVELY CONNECTED TO SAID CONTACTS FOR OPERATION THEREOF; SAID ELECTROMAGNET COMPRISING A CORE AND AN ENERGIZING WINDING THEREFORE; SAID CORE COMPRISING A MOVABLE CORE MEMBER AND A RELATIVELY STATIONARY CORE MEMBER; MEANS BIASING SAID FIRST CORE MEMBER AWAY FROM SAID SECOND CORE MEMBER; MEANS MOUNTING SAID FIRST CORE MEMBER FOR MOVEMENT IN A FIRST DIRECTION TOWARD SAID SECOND CORE MEMBER UPON ENERGIZATION OF SAID WINDING; FIRST MEANS SUPPORTING SAID SECOND CORE MEMBER AND CONSTITUTING MEANS FOR ABSORBING DIRECT SHOCK BROUGHT ABOUT BY ENGAGEMENT OF SAID SECOND CORE MEMBER; SECOND MEANS SEPARATE FROM SAID FIRST MEANS FOR NORMALLY LIMITING MOVEMENT OF SAID SECOND CORE MEMBER IN A SECOND DIRECTION TOWARD SAID FIRST CORE MEMBER; SAID SECOND MEANS INCLUDING A RESILIENT PORTION OPERATIVELY ENGAGING SAID SECOND CORE MEMBER SO AS TO YIELD TO A LIMITED EXTENT AS SAID SECOND CORE MEMBER REBOUNDS UNDER THE INFLUENCE OF SAID FIRST MEANS, SAID SECOND MEANS INCLUDES A PLATE, A SPRING, AND A STOP; SAID SPRING URGING SAID PLATE AGAINST SAID STOP; SAID PLATE EXTENDING INTO A RECESS IN SAID SECOND CORE MEMBER; SAID RECESS AND SAID PLATE BEING SO PROPORTIONED AS TO PERMIT MOVEMENT OF SAID SECOND CORE MEMBER RELATIVE TO SAID STOP.

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