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Publication numberUS2783329 A
Publication typeGrant
Publication dateFeb 26, 1957
Filing dateSep 7, 1955
Priority dateSep 7, 1955
Publication numberUS 2783329 A, US 2783329A, US-A-2783329, US2783329 A, US2783329A
InventorsGlen Jackson
Original AssigneeGlen Jackson
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Thermo switch
US 2783329 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

Feb. 26, 1957 Q JACKSON 2,783,329

THERMO SWITCH Filed Sept. 7, 1955 Fig. 1,0

42 72 587/44 f2 Fly-2 5 7 |4852 l, 3 'i 7L t 20 A3@ 40W 50 65N(Il f "5 6- 4 /8 [yea 4 60 Il 4 75 4 c t WHW 'f'mlf www" i, l\

Fig. 4

G/en Jackson INVENJOR.

United States Patent liice 2,783,329 Patented Feb. 26, 1957 THERM() SWITCH Glen Jackson, Indianapolis, Ind. Application September 7, 1955, Serial No. 532,831

3 Claims. (Cl..200 115.5)

This invention relates to thermo sensitive snap switches and particularly to a plug-in circuit breaker of the manually reset type which is adapted to be used with any elec trical appliance.

An object of this invention is to provide an inexpensive thermo responsive switch capable of being manually reset when the circuit with which it is connected becomes overloaded, thereby protecting the radio, television or other electrical equipment from being damaged in the event that a short circuit is developed.

Another object of this invention is to provide a circuit breaker of the manually reset type, which is capable of "being plugged directly into the ordinary wall outlet and capable of accepting a customary pronged type plug whereby it may be used by anyone capable of inserting an electrical outlet plug into a receptacle.

These together with other objects and advantages which will become 4subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

'Figure l is a side view of the thermo responsive switch;

Figure 2 is a longitudinal sectional view taken substantially on the line 2 2 of Figure l;

Figure 3 is a longitudinal sectional View taken on the line 3 3 of Figure 2;

Figure 4 is a longitudinal sectional view taken on the line 4 4 of Figure 2; and

Figure 5 is a transverse sectional view taken on the line 5 5 of Figure 2 and in the direction of the arrows.

The thermo responsive switch comprises a twopiece body having sections 12 and 14 connected together by means of bolts 16 and 1S which pass through aligned passages therein. The heads and nuts of these bolts are preferably countersunk. lt is preferred that the body `section 12 and 14 be made of electrically insulating material, such as Bakelite or some other plastic material.

*Prongs 20 and 22 protrude from one end of the body, one prong being discontinuous and the other being continuous. Prong 22 is located in a passage 24 formed in the confronting surfaces of sections 12 and 14 and shaped to conform to the prong body or conductive strip 26. The prong proper 22 is formed by a returned portion of the prong body 26 and there is an achoring leg 28 embedded in an angularly extending part of passage 24. An offset 30 is formed in the prong body 26 adjacent the angulated end 32 disposed in recess 34. Recess 34 is -actually an enlargement of the passage 24 near one end thereof, and the extreme end of the passage 24 constitutes an appliance plug prong receiving slot 36. Angulated end 32 of prong body 26 is suiciently springy to grip the appliance plug prong firmly so that good electrical continuity may be established.

The prong 20 is constructed similar to the prong 22 including the angular portion 38 which is similar in construction and function to the angular portion 28. However, the prong body strip terminates in an end 40 which is disposed in a cavity 42. This cavity is formed in both body sections 12 and 14 and has a bimetallic snap `spring 44 disposed in it. Also located in the cavity 42 is an end 46 of prong body 48, prong body 48 being similar in shape -to the corresponding portion of prong body 24. It includes an offset 50 together with an angulated end 52 that is disposed in recess 54 formed in both of t-he body sections. Prong receiving slot 56 which opens into recess 54 is adapted to accommodate an appliance plug prong and coacts with the slot 36 to accept the plug.

A partition 58 protruding from body section 12 extends across a reduced portion 60 of the cavity 42. This partition has a threaded bore 62 in it in order to accommod-ate the screw 64. Bimetallicfsnap spring 44 is secured -to the upper end of this screw whereby t-he location of snap spring 44 may be adjusted by rotation of screw 64. A reduced shank 68 extends from screw 64 and is arranged parallel to the longitudinal axis thereof. This shank accommodates a push-button assembly 70 which extends through an lopening formed in the confronting surfaces of the body sections 12 and 14 and which communicates with cavity 42. Assembly 70 is of standard construction and includes a push button having a cavity accommodating a return spring that is seated therein, the return spring reacting on the push button and the reduced shank 68 yieldingly pressing the push button outwardly of the section 12 of the body. In this way, the button assembly 70 may be pushed from the exterior of the body, and it has feet 71 4and 72 adapted to come to bear against spaced parts of the snap spring 44 in order to reset it.

This snap spring has contacts 74 and 76 at the ends thereof adapted to rest on contacts 78 and 80 carried by the ends 40 and 46, respectively, of the interrupted prong 20.

In operation, the device 10 is inserted in an ordinary wall outlet or in any other outlet capable of accepting a plug. Then, the equipment plug has its prongs inserted in slots 36 and 56 and circuit continuity is established through the device 10. When there is a thermal overload, the bimetallic snap spring 44 will become distorted, thereby separating thecontacts on it from the fixed contacts 78 and 80. This will open the circuit with which the device 10 is associated. When it is desired to reset the switch and again close the circuit, the button assema Ibly 70 is pushed, thereby pushing the feet 71 and 72 against the bimetallic snap spring and, snapping it back to the position disclosed in Figure 2.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily -occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

l. A thermo sensitive switch adapted to be inserted in a receptacle and adapted to accommodate an electrical cord plug, said switch comprising a body having a rst body section and a second body section, means extending through said sections fastening said sections together, a conductive strip carried by said body and embedded therein, said conductive strip having a prong at one end thereof which protrudes from the end of said body, said body having a recess therein, the opposite end of said strip having an angulated portion disposed in said recess, said body having a slot in communication with said recess at the opposite end of said body and adapted to accept one prong of an electrical plug, an interrupted strip carried by said body, said interrupted strip including a prong protruding from the same end of said body as the previously mentioned prong, 4a strip portion having an angulated end, sa-id body having a slot in alignment with the recess wherein the last mentioned angulated portion is disposed, said last mentioned slot adapted 'to accept a prong of a plug and coacting with the previously mentioned slot to -accommodate an electrical equipment plug, the last mentioned prong portion and strip portion having inner ends spaced from each other, Va cavity in said body accommodating said inner ends, a bimetallic snap spring having contacts at the ends thereof normally touching said inner ends, -means `supporting said bimetallic snap spring in said cavity and including a partition which extends across said cavity, a screw adjustably carried by said partition, said snap spring being disposed on said screw, and manually operable reset means for returning said bimetallic snap spring when it is distorted due to a thermo overload condition.

2. The thermo sensitive switch of claim 1 wherein said manually operable reset means comprises a push button assembly carried by said body, said assembly including a member which is movable inwardly of said cavity, and spaced means on said movable member adapted to contact said spaced vspring in order to deect said spaced spring.

3. The thermo lsensitive switch of claim 2 wherein said v spaced means on said member comprise a pair of feet, and said feet being arranged to contact said snap spring on opposite Isides of said screw.

References Cited in the le of this patent UNITED STATES PATENTS

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1687167 *Mar 18, 1926Oct 9, 1928Mann Randolph MConnecting plug
US1990176 *Sep 29, 1931Feb 5, 1935Philip LauterFused connecter
US2125126 *Sep 1, 1937Jul 26, 1938Rivers Durward SElectric circuit protector
US2399406 *Jul 28, 1943Apr 30, 1946Westinghouse Electric CorpElectrical apparatus
US2406154 *Oct 12, 1944Aug 20, 1946Milton MedlinFused electrical plug
US2420300 *Dec 5, 1942May 13, 1947Pierce John B FoundationElectric overload protective device
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3197594 *Dec 28, 1962Jul 27, 1965Therm O Disc IncThermo-sensitive switch plug
US3546650 *Mar 19, 1969Dec 8, 1970Purer PhillipElectrical adapter
US4514715 *May 15, 1984Apr 30, 1985Chen Kun SSafety receptacle
US4864269 *Feb 25, 1988Sep 5, 1989Priebe Stanley RPortable electrical adapter
US5167535 *Apr 20, 1992Dec 1, 1992Alert Safety Lite Products Co., Inc.Female electrical plug with overload protection
US7489227 *May 4, 2006Feb 10, 2009Bsafe Electrix, Inc.Electrical receptacle with multiple heat sensors
US7791864 *Feb 7, 2008Sep 7, 2010Interface Group - Nevada, Inc.Electrical power control outlet and system
US20070257763 *May 4, 2006Nov 8, 2007Bsafe Electrix, Inc.Electrical receptacle with multiple heat sensors
US20080191831 *Feb 7, 2008Aug 14, 2008Matyas Raymond TElectrical power control outlet and system
U.S. Classification337/91, 337/113
International ClassificationH01H77/00, H01H77/04, H01R13/70, H01R13/713
Cooperative ClassificationH01R13/713, H01H77/04
European ClassificationH01H77/04, H01R13/713