US2186476A - Electrical connector - Google Patents

Description

I Jan. 9, 1940.

J. G. DEBBY ELECTRICAL CONNECTOR Filed April 25, 1956 INVENTOR. JOHN ED may.

ATTORNEY.

Patented Jan. 9, 1940 John G. Debby, Cleveland, Ohio Application April 23, 1936, SerialNo. 76,061

Claims.

This invention relates to electrical connectors and particularly to electrical switches for carrying heavy currents.

One of the principal objects of the present invention is to provide a connector of this character in which better and higher pressure contact between the blade and blade receiving clips is effected so that the switch is capable of carry- U ing greater currents without danger of burning and overheating and with a reduction in current losses through the connections.

A more specific object is to provide a switch in which positive wedging contact pressure is effected merely by throwing the switch in the usual manner and in whichthe switch is maintained in the closed condition without loosening under vibrational and other such forces by such wedging pressure.

Another object of the present invention is to effect adequate contact pressure between the the blades and the blade supports.

Another objectis to provide a switch of this character in which the usual limit stops are eliminated. l

Other objects and advantages will become apparent from the following specification wherein reference is made to the drawing in which Fig. lis a plan view of a switch embodying the principles of the present invention, the switch being shown in open condition;

Fig. 2 is a plan view 0 the switch in closed condition; i

Figs. 3 and 4 are vertical sectional views, taken on planes indicated by the lines 3-3 and 4-4 respectively in Fig. 2;

Fig. 5 is a vertical sectional view taken on a plane indicated by the line 5-5 in Fig. 3;

Fig.- 6 is a perspective view of a contact and clamping element used in connection with the present invention; and I Fig. '7 is a sectional view similar to Fig. 4 illustrating a modification of the invention.

For the purposes of illustration, the invention is shown in connection with the usual blade type switch, its use in connection with other types of connectors being readily apparent therefrom.

Heretofore in switches of this character, means havebeen provided for limiting the separation of the blade receiving clip arms so as to provide a better contact between the arms and the blade. In other types, this contact has been increased by the use of screw wedges which, after the switch is thrown, are screwed into place so as to wedge the blade and clips tightly together. Even in this latter type, however, the wedging actionis such that the contact pressure is dependent upon the rigidity of the clip arms.

regardless of the rigidity of the blade or clip and, inv addition thereto, the path for the current is doubled. I

In the present structure, adequate wedging pressure is obtained 7 Referring to the drawing, the switch, designated generally as l, comprises the usual insulating base 2 at one end of which are carried the blade receiving clips 3 and at the other end of which are mounted the movablecontact blades 4, the latter being secured together by a suitable insulating bridge 5, carrying the usual operating handle, 6. As better illustrated in Figs. 3 and 4, each of the clips 3 comprises a pair of spaced arms 1 which are preferably formed integral with each other and are secured to the base 2 by suitable means such as the screws 8.

The arms I, at their blade receiving portion, are spaced apart a distance equal to the thickness of the blade 4 to be associated therewith and have plane adjacent contact surfaces. These surfaces may converge slightly toward the base 2, so as to guide the blade therebetween but they are so related that when the blade is therebetween and the arms are wedged into operating positionagainst the blade, the surfaces are parallel with the cooperating surfaces of the blade permanently fixed directly on the arms I. The

portions la may be cast out of brass or copper plated steel integral with the arms I or the usual copper strip arms may be used with the wedge portions 1a soldered thereto so as to form therewith a substantially unitary structure. "In either event the portions 1a are of conducting'material and connected to the arms with a highly efiicient electrical connection.

Carried one on each blade 4 are rigid frames Ill, each frame comprising rigid side frame members Illa and rigid end frame members lb. The side frame members extend generally parallel to theassociated blade and are spaced apart from each other and .fromopposite faces of the blade so that the wedge portions Ta of the arms 1 may be received, one wedge portion between each side frame member Mia and the blade 4 when the blade is moved to position between the arms. The end frame members are preferably spaced apart a distance slightly greater longitudinally of the blade than the corresponding dimension of the clip arms I so as to compensate for the arcuate path of the blades l as they enter the clip arms.

The illustrative embodiment is one in which the frames IE are provided for installation on a standard switch blade, the provision of such in a specialized switch being readily apparent. In the illustrative embodiment, the frames iii are sep arately formed and mounted on the arms t. For this purpose, the end frame members lllb are provided with slots lllc through which the blade 4 is received. If desired, the frame it may be mounted with slight clearance edgewise of the blade longitudinally thereof so that it may adjust itself conveniently or readily for slight inaccuracies in manufacture. For rough manufacture slight transverse clearance may be allowed also. The inner surfaces of the frame members Eda are convergent toward the free ends of the clip arms l and parallel respectively to the Wedge portions lla' of the arms, thus providing wedge portions led which are in fixedly spaced relation to each other transversely of the blade. Thus when the blade d is swung downwardly between the clip arms 1, the wedge portions la of the arms and illd of the frame cooperate to wedge the arms into firm face to face contact with the opposite faces of the blade i, the pressure exerted being extremely great so that a highly efficient contact pressure between the blades and arms is obtained.

Here it should be noted that when attempts are made in switches to Wedge the blade laterally outwardly against oneof the clip arms, or to wedge one arm tightly against the blade, spreading of the arms apart, due to their own resiliency, or a movement and deflection of both the blade and the arms away from the wedge result so that only part of the force of the wedge is effective unless the blade or arms, or both, are extremely rigid or heavily buttressed. In the present structure, however, equal and opposite forces are applied by the wedges at opposite faces of the blade so that equilibrium is obtained and the arms and blade are subjected only to direct compressive stresses. Since the forces of the wedges are in opposition to each other, extraneous buttressing of the arms or blade against the force of the wedges is unnecessary. The wedges are so related that the blade is fully between the arms before any appreciable wedging pressure is exerted, so as to insure full final surface contact with the blade. Obviously, the wedging pressure, however, is partially applied at the initial operation of the wedges as a result of which wiping contact under appreciable pressure between the blade and the complementary contact surfaces of the arms i is ob tained. Due to the coaction of the wedge por tions and the clamping of the blade therebetween, limiting of movement of the blade 1 towards the base 2 beyond a predetermined position is effected by the same wedge portions, this limit being reached after the arms have been pressed firmly against the blade. Consequently no bottom or end limit abutment such as is customary in switch clips is necessary. In fact, such is undesirable as it might be reached by the blade after long use and Wear before the and its associated connector.

wedges are in full clamping position. With the present structure and without the limit stop, however, a great amount of wear is possible before the switch is inefficient as the wedge portions inherently compensate for the wear and insure stopping of the blade between the arms. Having thus obtained such effective contact between the blade and arms, equally effective contact is inherently provided between the Wedge portions la and wedge portions lfld of the frame members Ella.

In order to utilize this greater contact area for carrying current while at the same time eliminating losses in its passage from the frame members to the blades through the comparatively loose connection afforded, flexible shunts ll of adequate capacity are permanently soldered or connected to the side frame members Holland, in turn, connected permanently to the blades 4. The shunts ii are preferably of woven wire and of such capacity that they themselves can carry half or more of the current passing through the switch. Thus when the switch is closed, four distinct large surface area contacts and paths for the current are provided between each blade Again, the shunts it serve to secure the frames in position longitudinally on the blades 1 while permitting slight limited movement thereof along the blades, so

that the frames can accommodate themselves readily to the clips.

The arms i tend normally to spring apart slightly when the pressure is removed and will be in engagement with the side frame members We or the blade l until the wedging pressure is completely removed, at which time a quick separation over the entire surface of one or the other is effected and, since both the blade and frames are conductors, sparking and burning are eliminated.

The blades 3 are mounted in the customary manner between the arms of suitable supports l2, being pivotally secured thereto by bolts I 3 which draw the arms tightly into contact with the butt ends of the associated blades. Since, however, the larger current carrying capacity for a given size switch is provided by the frames ii] and shunts H and due to the more efficient contact between the switch blade and the clip arms i, it quite often happens that the current carrying capacity at this connection is greater or more efficient than between the arms of the supports l2 and blades i, especially if for any reason the bolts 13 become loosened.

In order to provide better contact between the butt of each blade and the supports l2, each blade may be provided with a spring yoke M, such as illustrated in Fig. 6, of highly conductive and spring material. Each of the yokes it comprises arm portions Mia adapted to receive therebetween the switch blade i and clamping portions Mb. The yokes M are mounted permanently on the blades t near the butt ends thereof and adjacent the supports 82, suitable clampin being effected by means of a bolt-I5, as illustrated in Fig. 3. When so mounted, the clamping portions Mb of the wires 14 extend rearwardly in a position to pass over and engage respectively the outer surfaces of the arms of the supports 52 when the blades 4 are moved to closed position. The portions lib are preferably flared slightly apart toward the support 12 so as to be guided into place thereon. When the switchis closed, the yokes M press the arms of the supports 12 firmly against the faces of 2. An electric switch having a blade with subthe associated blades. 4 and at the same time provide a firm but yieldable electrical contact between the portions Mb and the arms of the support 12. Thus, again, four distinct current paths and contact surfaces are provided at the butt end of each blade and wiping action is obtained at all contacts.

In some instances it is desirable to utilize this invention in connection with a double throw switch. For such purposes the structure illustrated in Fig. 7 may be utilized. In this modified structure, the parts corresponding to the parts heretofore described are indicated by corresponding primed numerals. The primary difference between this and the previous structure resides in the wedges utilized which will be described specifically.

extensive with the arms in the direction of movement of the blade 4. Instead, they merge with oppositely facing wedge portions 2011- which cooperate with the opposite set of fuse clip arms customarily provided in a double throw switch. In operation, however, the advantages are the same in either instance. Obviously, in a double throw switch, if yoke members, such as the mem- I bers M, were provided, double sets of clamping portions Mb would be necessary so as to engage the blade supports of the double throw switch regardless in which operating position the blade 47 might be disposed' Since the current carrying capacity of a switch is largely determined by the surface area of the conductors and by the efficiency of the contact surfaces and the contact pressure, it is apparent that the present structure is capable of carrying a great amount of current for a given size of switch in comparison with structures heretofore provided. Obviously, in those instances Where laminated blades are used, the frames It may be.

formed by bending outwardly the end portions of the outer laminations, thus forming, in effect, a frame structure, but in such instance, it is usually desirable to reinforce the same due to the yieldability of the copper and the tendency .of the same to stretch and spread and thus partially relieve the wedging action. In those instances in which the blade receiving clip comprises only a single arm, equally effective contact between'such arm and a single face of the blade can be obtained.

Having thus described'my invention, I claim: 1. An electrical connector having a blade and. a clip the latter having arm portions adapted to receive the blade between them in sliding engagement therewith, means mounting the blade and clip for relative movement enabling separation and bringing together of said parts substantially in the same relationship each time the connector is operated, a frame member on the blade with mutually rigid opposite side portions, positioned for engagement with respective arms, the engaging surfaces of the frame sides and arms being 7 angularly disposed so that they wedge against each other to increase the pressure between the slidably engaged surfaces and finally arrest the sliding relative movement of the blade and arms.

stantially parallel opposite sides and a clip with spaced surfaces which face each other and are substantially parallel when engaged with saidv blade surfaces, spaced mutually rigid members on the blade and similarly spaced non-yielding surfaces on the arms, said members and surfaces being angularly related in a mann'erto effect -mutual wedging to cause the first-named clip surfaces to press against the parallel blade sides when the blade and clip are moved relatively into circuit-closing position.

3.- In an electric switch, a blade of current carrying material, a clip of current-carrying material havingarms adapted and arranged to embrace and make contact with the blade, a substantially rigid metallic frame carried on the blade with sufficient lcoseness to permit floating movement of the frame on the blade,said frame having spaced relatively fixed surfaces adapted to make Wedging, travel-limiting contact with outer side surfaces of the arms for increasing the contact pressure between the blade and arms and forming a stop against furtherm'ovement when the switch is closed, and flexible, electrically conductive means connecting the frame and blade.

' l. In an electrical switchdevice, a connector having a pair of spaced contact arms, a blade ,mounted for movement from an open to a closed position and received between the arms when in: closed position, wedge means on the outer faces of saidvarms, cooperating Wedge members carried by the blade and engageable with said wedge Imeans for moving the arms relatively'toward each other and against the blade when the blade is received between the arms, means rigidly constraining said wedge'surfaces from relative separation transversely of the blade over their entire operating faces, and means mounting said wedge members on the blade for slight floating movement longitudinally of the blade.

a 5. In an electrical connector including a contact member having a pair, of spaced contact arms with free end portions, a movable blade member mounted for movement edgewise into position between said arms from'the free end portions thereof, a transversely rigid frame carriedfby the blade member and having end frame portions and side frame portions which are connected at their ends to the end frame portions and which are spaced laterally from the blade member, said frame being open at the edge, of the blade member, internal wedge members carried by said side frame-members and spaced out-' wardly fromopposite faces of the blade member, respectively, for accommodating the arms between the wedge members and the blade when the blade is moved into contact position with the arms, said internal wedge membersbeing divergent in the direction of movement of the blade toward contact position, complementary wedge members on the outer faces of the arms and cooperable with the internal wedge members, re-.

spectively, for moving the arms into firm con tacting engagement with the blade when the 7 blade is moved tocontact position to materially increase the contact pressure between the arms and blade and to limit the movement of the blade edgewise between the arms when the blade is moved into position between the arms;

JOHN G. DEBBY.

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