US2125126A

US2125126A - Electric circuit protector

Info

Publication number: US2125126A
Application number: US161894A
Authority: US
Inventors: Durward S Rivers
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-09-01
Filing date: 1937-09-01
Publication date: 1938-07-26
Anticipated expiration: 1955-07-26

Description

July 26, 1938. 11 RlVERs 2,125,126

ELECTRIC CIRCUIT PROTECTOR 7 Filed Sept. 1, 1957 2 sheets-Sheet 1 3 Wye/flak Du/"Ward 6. Ewe/'13 M25. m x, 47% for/152%? July 26,, 1938. Di 5 v g 2,125,126

ELECTRIC CIRCUIT PROTECTOR Filed Sept. 1, 1957 2 Sheets-Sheet P Patented July 26, 1938 UNITED STATES PATENT OFFICE ELECTRIC omcm'r rnorao'ron' Durward S. Rlveranlndianapolis, Ind. Application September 1, 1937, Serial No. 181,3 3;

' Claims. (c1. zoo-415.5)

quired degree of accuracy, and which may be' reset without having to replace parts after the overload condition has been removed.

Another important feature of the invention is that the protecting device may be present in every extension cord in series with the common link fuse.

. Further important advantages of the invention are to be found in the small and compact structure and particularly in the unique combination of these various elements as set forth in the appended claims.

These and many other objects and advantages of the invention willbecome apparent to those versed in the art in the following description of the invention as illustrated in the accompany-- ing drawings in which:

Fig. 1 is a side elevation in partial section of the plug adapter embodying the invention;

Fig. 2, a top plan view in partial section;

3, a transverse section on the line 3-3 in Fig.

Fig. 4, a section on the line 4-4 in Fig. 1;

Fig. 5. a central longitudinal section through the cord plug embodying the invention;

Fig. 6, a similar section on the plane 90 degrees from that 01' Fig. 5;

Fig. 7, a transverse section on line 1-1 in Fig. 6; and o Fig. 8, a transverse section on line 8-8 in Fig; 6.

Like characters of reference indicate like parts in the various views in the drawings.

Referring to the drawings, the structures are shown on an enlarged scale.

Referring first to the form oi the invention as illustrated in Figs. 1-4, a body I. is formed from some suitable insulating material to have an enlarged head ll, herein shown as being slotted in two directions 90 degrees apart across its outer end. A terminal prong I2 is attached to the body ill by its inner end by means of the screw ii to have the prong l2 carried within one of the slots through the head II and extending therebeyond. Between the head 01 the screw l3 and the prong l2is positioned a foot of the contactor is. This contactor l5 extends rearwardly along the body Ill to bend thereagainst in a yielding manner within the groove l6 formed along that side of the body It). The rearmost end 0! the contactor I5 is turned outwardly so that the connecting prong 5 I1 01 the connecting plug (not shown) may be inserted between the contactor l5 and the side of the body In within the groove I6. I

On the opposite side of the body In a prong I8 is carried in parallel relation to the prong l2 and 10 is mounted on the body In by extending inwardly through the head H and having a foot l9 turned at right angles to abut the outer end of the body l0 within the transverse slot across the head II. The side slot through thehead ll prevents turnmg of the prong l8 and a rivet is passed entirely through the body l0 axially to be headed by one end over the root is and by the other end within the slot in the rear end of the body.

Between the rear head of this rivet 20 and the 20 body is secured an end 01 a bi-metal strip 2| which is carried laterally from the body l0, Fig. 1, and

thence is bent around to be substantially parallel withthe body It) and is carried iorwardly' through .the longitudinal slot in the head H to terminate in a hooked end 22.

On the opposite side of the body II! from the strip 2| is anchored a toot of'the spring 23 by means of a screw 24. This spring 23 is carried forwardly through the longitudinal slot in the head I I and is bent around and across over the end slot in the head to terminate by a rounded end normally engaged under the hook 22 of the i bi-metal 2|. The strap 25 is interposed by one. end between the screw 24 and'the spring 23 and is carried around the body ID to the side thereof oppositeto the screw I 3 where the screw 26 passes through the foot of the second contactor 21 and through the strap 25 to engage the body ID.-

This contactor 21 is similar in shape to the contactor I! and yieldingly presses against the'side of the body -Il within the groove or slot 28 into which the second prong 29 in the connecting plug (notshown) is engaged undenthe contactor 21. Thus it is to be seen that an electrical cir- 4 cult is established between the contractor 21 and the prong I! through the strap 25, spring 23, bimetal 2| and the rivet 20.

In order to enclose the structure above described, an insulating housing 30 is provided to receive the body II and the head H. The housing 30 is provided with a pair of slots 3| and 32 through which the prongs l1 and 29 may be inserted through the end of the housing to be engaged with the contactors as" above explained.

the detents on its outer face, whereby the body l and the parts mounted thereon are firmly supported by the cap 34 when this cap 34 is pushed in the counterbore in the housing 30 and-seated B8 e H. r diameter of the cap 34 made to be such that there is a pressed fit between the cap and the wall of the housing so that the cap 34 will be firmly retained thereby.

' The thickness of the cap 34 and the position of the shoulder 33 are. madeto be such that there is a substantial distance left within the outer end of. the housing beyond the-outer face of the cap. This space is provided for travelof the reset button 31 which slidingly passes through the cap 34 in the path of the spring 23; The button 31 is provided with a head 38 on its inner end to limit the outward travel of the button.

The bi-metal. 2| is selected as to composition, shape and size to carry the normal full rated capacity of the circuit without distortion. However, when the circuit fiow exceeds that predetermined figure, the bi-metal 2| will bend 'by its hook end away from the body l0 and toward the wall of the housing 30 so as torelease the end of the spring 23 and thereby break'the circuit. When the spring 23 is released, its free end will tend to move toward the cap 34 and will therefore pushthe button 31 outwardly and give indication of an open circuit.

Before the circuit can be re-established, the adapter must be removed from its receiving socket or. attaching plug, in ordei that the button 31 may be pushed inwardly to re-engage the spring 23 with the bi-metal end 22. By the time the adapter has been removed for this operation, the bi-metal 2| will have been cooled sufficiently to have returned to its original position for spring engagement.

The adapter, of course, will be used in -the circuits which are normally fused at some distribution point and the opening of the circuit in the adapter is preferably made to be such that the circuit will be broken'in the ada'pter'at a lower current flow than will blow out the fuse at the distribution point.

Where the circuit protector may be used directly by connecting'it on the end of the ex-. tension-cord, the structure shown in Figs. -8 is employed. In this form there is a body 40 which carries along one side thereof a terminal prong'4i, passing through the slot in the head portion 42 so that the single terminal screw 43' will retain the prong 4| inpositlon bypassing through the inner end of the prong into .the body. One of the wires 44 ofthe cord is secured against the prong M by the screw 43.

Along the opposite side of the body 40 and extending through the slot therealong is positioned the other terminal prong 45 which has a foot 46 turned over onto the inner end of the body 40. The strip of the bi-metal 41 is connected and interposed between the foot 45 and the securing screw 48 which passes through the strip and foot to engage the body 40. This -bimetal strip 41 is carried laterally from the foot 4 body 40 by the attaching screw 52.

50 extends forwardly into the transverse slot 43 a distance and then is bent around to extend freely through the longitudinal slot on the side of ,the body 40 to terminate by the hook end 49 within the transverse slot across the outer end of the body 40.

On the side of the body opposite the slot carrying the bi-metal 41, is carried a spring 50 under the terminal plate 5i whichis secured to the The spring across the end of the body 40 to have the rounded end normally engaged under the hook end 49 of the bi-inetal. 'The other wire 53 of the cord is electrically connected to the plate 5i by means of the terminal screw 54.- Thus the circuit is established between the wire 53 and the prong '45 through the spring 50 and the bi-metal 47.

An enclosing housing 55 is provided to receive the wires 44 and 53 through the opening in one end. The cap 56 closes the other end'of the housing by frictional engagement within the counterbore thereof. This cap 56 is slotted and permits the prongs 4| and 45 to extend therethrough, and in the same manner as described above, the prongs 4| and 45 carry the respective detents 51 and 58 to bear against-the outer face of the cap 53 as means to hold the body 40 snugly against the inner face, the reset button 59 slidingly passing through the cap 56 and having a limiting head 50 on its inner end. The head 60 is in the pathof-the spring 50 whereby the button 59 will be moved outward as indicated by dash lines when the circuit is interrupted by the movement of the bi-metal 4'landwhereby the spring 50 may be restored to engagement with the bi-metal by pushing in on the button.

While I have herein shown and described my invention in the form as now best known to'me, it is obvious that yarious structures may be employed'without departing from the spirit of the invention and I therefore do not desire to be limited to that precise form beyond the limitations imposed by the following claims.

I claim: 1. In a circuit protector, a body carrying a pair of terminal prongs, means fixing said prongs in alignment on said body, a thermostatic metal strip carried by the body, a spring actuated member carried by the body and normally releasably engaged with said strip in series relation with one .of said terminal prongs and a connecting terminal, whereby the circuit may be interrupted upon distortion of the strip through heat from a predetermined current overload to release said spring from said strip, a housing surrounding the body, a housing closure supporting said body, an indicating and reset button in the path of said spring guided and limited in outward travel through said closure, said prongs being carried. through said closure, saidhousing having aportion projecting beyond said closure in the direction.of said prongs at least as far as the outward limit-oi travel of said button.

2. In a circuit protector, a body carrying a pair of terminal prongs, means fixing said prongs in alignment on said body, a thermostatic metal strip carried by the body, a spring actuated member carried by the body and normally releasa'niy engaged with said strip in seriesyrelation with one of said terminal prongs and a connecting terminal, whereby the circuit may be interrupted upon distortion of the strip through heat from 2,1'as, 1 as an indicating and reset button in the path of said spring guided and limited in outward travel through said closure, said prongs being carried through said closure, said housing having a portion projecting beyond said closure in the direction of said prongs, at least as far as the outward limit of travel of said button, said terminal comprising a spring member yieldingly pressed toward the body, and a second like terminal spring member electrically connected to the other of said prongs, said housing having openings arranged to permit engagement of other prongs therethrough with said terminal members, whereby said protector may be used as an intervening adapter between the male and female parts of a standard connecting plug.

3. In a-circuit protector, a body of insulation slotted along one side, a connecting prong positioned in said body slot secured thereto and carrying a terminal, said body being provided with a second slot on its opposite side, a second prong carried in said second slot and having a foot turned over onto the body, means for securing the foot to the body, a thermostatic metal strip electrically connected to said foot and rigidly mounted by one end in relation to the body, said strip being carried along a side of the body removed from either prong side, a conductor secured by one end on the body opposite said strip side and carried therealong to turn in a yielding manner over the body end into releasable normal engagement with said strip between said prongs, a housing about said body, and a housing closure at one end of the housing carrying said 'body'to have said prongs extend outwardly through the closure, and a reset button slidingly carried by the closure in the path oi-said conductor, said housing having a portion extending beyond said closure within which extension said button may travel.

4. In a circuit protector, a body of insulation slotted along one side, a connecting prong positioned in said "body slot secured thereto and carrying a terminal, said body being provided with a second slot 'on its opposite side, a second prong carried in said second slot and having a foot turned over onto the body, means for securing the foot to the body, a thermostatic metal strip electrically connected to 'said toot and rigidly mounted by one end in relation to the body, said strip being carried along a side of the body removed from either prong side, a leaf spring secured by one end on the body opposite said strip side and carried therealong to bend over the body end into releasable normal engagement with said strip between said prongs, a housing, about said body, and a housing closure at one end. of the housing carrying said body to have said prongs extend outwardly through the closure, and a reset button slidingly carried by the closure in the path of said spring, said housing having a portion extending beyond said closure within which extension said button may travel, a detent on at least one oi said prongs engaging the outer face of said closure whereby said body will be firmly abutted against the inner face of the closure after the prongs have been passed through the closure to permit said detent to engage said outer face.

5. In a circuit protector, a body of insulation slotted along one side, a connecting prong positioned in said body slot secured thereto and carrying a terminal, said body being provided with a second slot on its opposite side, a second prong carried in said second slot and having a foot turned over onto the body, means for securing the foot to the body, a thermostatic metal strip electrically connected to said foot and rigidly mounted by one end in relation to the body, said strip being carried along aside of the body removed from either prong side, a leaf spring secured by one end on the body opposite said strip side and carried therealong to bend over the body end into releasable normal engagement with said strip between said prongs, a housing about said body, and a housing closure at one end of the housing carrying said body to have said prongs extend outwardly through the closure, and

, a reset button slidingly carried by the closure in the path of said spring, said housing having a portion extending beyond said closure within which extension said button may travel, a detent on at least one of said prongs engaging the outer face of said closure whereby said bodywill be firmly abutted against the inner face of the closure after the prongs have been passed through the closure to permit said detent to engage said outer face, said closure being a part separate from said housing and attached thereto by frictional engagement within a bore in the housing.

6. In a circuit protector, a body of insulation slotted along one side, a connecting prong positioned in said body slot secured thereto and carrying a terminal, said body being provided with a second slot on its opposite side, a second prong carried in said second slot and having a root turned over onto the body, means for securing the foot to the body, a thermostatic metal strip electrically connected to said foot and rigidly mounted by one end in relation to the body, said strip being carried along a side of the body removed from either prong side, a leaf spring secured by one end on the body opposite said strip side and carried therealong to bend over the body into releasable normal engagement with said strip between said prongs, a housing about said body, and a housing closure at one .end or the housing carrying said body to have said prongs extend outwardly through the closure, and a reset button slidingly carried by the closure in the path of said spring, said-housing having a portion extending beyond said closure within which extension said button may travel, ahead on said body at said body end having a transverse slot thereacross receiving said bent over spring end thereacross, said metal having a hooked end presented a mmwann s. Rrvans.