CA1045189A - Electrical power plug with series connected fuse - Google Patents
Electrical power plug with series connected fuseInfo
- Publication number
- CA1045189A CA1045189A CA238,503A CA238503A CA1045189A CA 1045189 A CA1045189 A CA 1045189A CA 238503 A CA238503 A CA 238503A CA 1045189 A CA1045189 A CA 1045189A
- Authority
- CA
- Canada
- Prior art keywords
- fuse
- plug
- contacts
- housing
- prongs
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R31/00—Coupling parts supported only by co-operation with counterpart
Landscapes
- Fuses (AREA)
- Coupling Device And Connection With Printed Circuit (AREA)
Abstract
TITLE ABSTRACT OF THE DISCLOSURE An electrical power plug having a fuse positioned within the plug housing. The fuse is formed from an elongated plastic fuse holder having a wire fuse element extending through each end. One end of the fuse holder contacts a planar contact plate which is connected to the electrical prong. An insulated wire entering the plug has a terminal secured to one end thereof, and means are provided for holding the terminal against the other end of the fuse wire. The fuse holder is readily removed from the plug for quick and inexpensive replacement of the fuse wire.
Description
r`, ~L045~l89 BACKGROU'.~ID OF TH~ IIiV13~i'rIOi~i ~ield ol the Invention ~ .
This invention relates to electrical power plugs and, more particularly, to an electrical power plug having an internal fuse in series with the power line and the prong connector.
Description of the Prior Art :
Electrical fuses are in common use for protecting ;~
electric circuits in the event of a short circuit~ Normally, such fuses are found at a central terminal box for protecting a large number of electrical outlets or are contained within `-the electrical device being protected. However, these prior art fuses cannot be used in ma~ applications, either because the electrical device is not capa~le of holding a fuse or the electrical device is connected to electrical outlets havin~
unknown current ratings. In particular, it is o~ten desirable to place a fuse in series with a string of Christmas lamps.
~owever, the lamps themselves are not large enough to hold a coRventional fuse and~the fuse rating of the soc~et to which the string of lar,lps i9 connected is often unknown. Compounding this problem is the practice of placing a large nurnber of such strings in series. ~
:. ., . :.
Placing a fuse in series-wi~h a string of Christrnas lights ia desirable for reasons of economy as well as safety since a safety cer~ification can be obtained~using a smaller gauge wire in the circuit i~ the circuit also con~ains a ~useO ~ ~
This allows the use of a thinner wire wikhout sacrificing ~ ~ -safety, a feature which is particularly important in the field-of Christrnas tree decorations since~a thin wire is easier to hide~among the branches~and is~also less expensive. The high flammability o~ such Chri~stmas trees~also mak~s saf~ty the factor of primary importanc~
.. . .
10~5~8~
SUM~RY OF THE INVENTION
It is an object of the present invention to provide an electrical plug containing a fuse which is easily replaced.
It is another object of the present invention to provide such a fuse which is relatively inexpensive.
It is a further object of the present invention to provide a fuse which is extremely compact, thereby maintain-ing the plug at a conventional size.
It is still a further object of the present invention to provide a fuseable electrical plug which is inherently reli~
able yet inexpensive to manufacture~
These and other ob~ects of the present invention are provided by an elongated fuse holder carrying a wire fuse ele`-ment extending beyond each end of the fuse holder. One end of the wire fuse rests against a planar contact plate connected to a conventional electrical prong adapted to be inserted in a wall socket. The other end of the wire fuse is held against a terminal which has been crimped to the end of the power line.
The fuse holder is extremely compact and is held in place in parallel alignment with the electrical prong, thereby insuring a compact configuration. The fuse element consists only of a wire, and no soldering or special manufacturing pro-cesses are needed. Thus the fuseable electrical plug of the present invention is inexpensive to manufacture and the fuse is readily replaceable. Furthermore, the simplicity of the - design insures that the plug is inherently reliable.
BRIEF DESCRIPTION OF T~E DRAWINGS
Fig. 1 is an isometric view of the fuseable plug of the present invention shown as assembled.
`~ 30 Fig. 2 ls an exploded isometric view of the fuseable plug of the present invention.
~, .
1045~9 Fig. 3 is a top plan view of the fuseable plug of the present invention.
Fig. 4 is a cross-sectional view of the fuseable plug of the present invention taken along the lines ~-4 in Fig. 1.
; DETAILED DESCRIPTION OF THE INVENT:[ON
Referring now to the drawings, the plug housing 2 contains a pair of prong recesses ~1 adapted to receive the prongs 24 and allow the ends thereof to pass through the end of the plug housing 2. The prongs 24 have formed thereon a --plug tab 28 for contacting the prongs of an add-on plug which may be inserted at the rear of the plug housing 2. The plug housing 2 contains an add-on plug recess 6 for allowing entry of the add-on prongs tnot shown) into the plug housing 2. Each of the prongs 24 contains a planar contact plate 26 which ex-tends from the prong 24 at a right angle.
The plug housing 2 also contains fuse recesses 8 for allowing insertion of fuse holders 30. The fuse holder 30 is an elongated rectangular plane of plastic having integral tabs at each end, each of which contains a bore through which a wire fuse element 32 is inserted and an angled corner 50 corresponding to an angle on the corner of the fuse recesses 8 for insuring that the fuse holder 30 is properly oriented while being inserted into the fuse recess 8. Each end of the fuse element 32 is then bent over each end of the fuse holder 30.
The fuse element 32 can be formed from any electrical con-ductor having a known resistance and a known melting point.
The fuse element 30 will have various current ratings, depend-ing upon the diameter of the wire that constitutes the fuse element 32. The diameter of the bores in the tabs is not critical and, therefore, a wide variety of wire diameters may be accommodated for a given sized bore. The fuse holder 30 ~ .
~, .
~r 10451~9 is inserted into the fuse recess 8 until the end of the fuse wire 32 rests against the contact plate 26.
As best sho~m in Fig. 3, a pair of insulated leads 18 enter the plug housing 2 at a wire port 16 and enter grooves 14 which guide the lea~s 18 to the proper location. The leads 18 are forceably inserted in the yrooves 14 to cause the leads 18 to be frictionally held in place. For this reason, the grooves 14 provide strain relief so that the leads 18 camlot be forceably removed from the plug~ A contact 22 is secured to the conductors in the insulated leads 1~, either by crimp-ing or solderin~. The contacts 22 are held securely in place above the end of the fuse holder 30 by the yrooves 14. The contacts 22 are separated from each other by a projection 20 which, as will be explained hereinafter, also insures precise alignment of the cover 34 with the plug housing 2. The fuse holder 30 is easily re~oved from the plug housing 2 by forcing~
the ends of the pronys 24 into tne plug housing 2, tl~ereby forcing the fuse holder 30 out the other end of the plug housing 2 by the contact plate 26. A new fuse wire 32 is then cut to length and inserted through tne holes at each end ~ ~-of the fuse holder 30 and bent over each end. Finally, the ~ fuse holder 30 is reinserted in~ the fuse recess 8 after the end of the prong 24 has been-puIled back to its original ~positîon.
~ cover 34 is secured to thè plug housing 2 by~
screws~46 which extend through the screw holes lO~in the plug ~ housing 2 and engage the threaded bores~36 in the cover 34.
-~ The cove~34 contains an aligmnent slot 42 which receives the~
~alignment projection 18 on the plug housing 2 to insure that ;
~the rotational position between the cover 34 and the plug ;
housing~2 is correct. Further alignr,lent is provided by pro-jections~38 in the cover 34 which are inserted inta cylLndri-cal racesses 12 in axial alig~ment with the screw holes 10 1~45~
and tab 39, which fits into recess 41. The cover 34 further includes contact projections 40 which hold the contacts 22 against the ends or the fuse holder 30 to insure conduction between the contacts 22 and the Euse wire 32. The fuse holder 30 is formed from a resilient plastic which, when compressed between the contact projections 40 and the contact plates 26, forms an arc to maintain the ends of the fuse wires 32 in contact with the contact plates 26 and contacts 22.
The cover 34 further includes a pair of add-on plug slots 44 through which the prongs of another plug (not shown) can be inserted to enter the add-on plug recesses 6 and con-tac~ the plug tab 28, integrally formed from the prongs 24.
In this way, a plurality of plugs may be serviced from one socket. Note, however, that the add-on plugs will not be protected by the fuse of the present invention.
- Although the fuseable electrical plug of the present invention has been described as having a fuse in series with } each prong 24, adequate short circuit protection can beobtained by including a fuse in series with only one of the prongs. In this case, the non-fused prong will be identical to those in conventional use. Thus, it is to be understood that the present invention is not to be limited to the precise structure disclosed.
: .
~ ' .
~i ".
This invention relates to electrical power plugs and, more particularly, to an electrical power plug having an internal fuse in series with the power line and the prong connector.
Description of the Prior Art :
Electrical fuses are in common use for protecting ;~
electric circuits in the event of a short circuit~ Normally, such fuses are found at a central terminal box for protecting a large number of electrical outlets or are contained within `-the electrical device being protected. However, these prior art fuses cannot be used in ma~ applications, either because the electrical device is not capa~le of holding a fuse or the electrical device is connected to electrical outlets havin~
unknown current ratings. In particular, it is o~ten desirable to place a fuse in series with a string of Christmas lamps.
~owever, the lamps themselves are not large enough to hold a coRventional fuse and~the fuse rating of the soc~et to which the string of lar,lps i9 connected is often unknown. Compounding this problem is the practice of placing a large nurnber of such strings in series. ~
:. ., . :.
Placing a fuse in series-wi~h a string of Christrnas lights ia desirable for reasons of economy as well as safety since a safety cer~ification can be obtained~using a smaller gauge wire in the circuit i~ the circuit also con~ains a ~useO ~ ~
This allows the use of a thinner wire wikhout sacrificing ~ ~ -safety, a feature which is particularly important in the field-of Christrnas tree decorations since~a thin wire is easier to hide~among the branches~and is~also less expensive. The high flammability o~ such Chri~stmas trees~also mak~s saf~ty the factor of primary importanc~
.. . .
10~5~8~
SUM~RY OF THE INVENTION
It is an object of the present invention to provide an electrical plug containing a fuse which is easily replaced.
It is another object of the present invention to provide such a fuse which is relatively inexpensive.
It is a further object of the present invention to provide a fuse which is extremely compact, thereby maintain-ing the plug at a conventional size.
It is still a further object of the present invention to provide a fuseable electrical plug which is inherently reli~
able yet inexpensive to manufacture~
These and other ob~ects of the present invention are provided by an elongated fuse holder carrying a wire fuse ele`-ment extending beyond each end of the fuse holder. One end of the wire fuse rests against a planar contact plate connected to a conventional electrical prong adapted to be inserted in a wall socket. The other end of the wire fuse is held against a terminal which has been crimped to the end of the power line.
The fuse holder is extremely compact and is held in place in parallel alignment with the electrical prong, thereby insuring a compact configuration. The fuse element consists only of a wire, and no soldering or special manufacturing pro-cesses are needed. Thus the fuseable electrical plug of the present invention is inexpensive to manufacture and the fuse is readily replaceable. Furthermore, the simplicity of the - design insures that the plug is inherently reliable.
BRIEF DESCRIPTION OF T~E DRAWINGS
Fig. 1 is an isometric view of the fuseable plug of the present invention shown as assembled.
`~ 30 Fig. 2 ls an exploded isometric view of the fuseable plug of the present invention.
~, .
1045~9 Fig. 3 is a top plan view of the fuseable plug of the present invention.
Fig. 4 is a cross-sectional view of the fuseable plug of the present invention taken along the lines ~-4 in Fig. 1.
; DETAILED DESCRIPTION OF THE INVENT:[ON
Referring now to the drawings, the plug housing 2 contains a pair of prong recesses ~1 adapted to receive the prongs 24 and allow the ends thereof to pass through the end of the plug housing 2. The prongs 24 have formed thereon a --plug tab 28 for contacting the prongs of an add-on plug which may be inserted at the rear of the plug housing 2. The plug housing 2 contains an add-on plug recess 6 for allowing entry of the add-on prongs tnot shown) into the plug housing 2. Each of the prongs 24 contains a planar contact plate 26 which ex-tends from the prong 24 at a right angle.
The plug housing 2 also contains fuse recesses 8 for allowing insertion of fuse holders 30. The fuse holder 30 is an elongated rectangular plane of plastic having integral tabs at each end, each of which contains a bore through which a wire fuse element 32 is inserted and an angled corner 50 corresponding to an angle on the corner of the fuse recesses 8 for insuring that the fuse holder 30 is properly oriented while being inserted into the fuse recess 8. Each end of the fuse element 32 is then bent over each end of the fuse holder 30.
The fuse element 32 can be formed from any electrical con-ductor having a known resistance and a known melting point.
The fuse element 30 will have various current ratings, depend-ing upon the diameter of the wire that constitutes the fuse element 32. The diameter of the bores in the tabs is not critical and, therefore, a wide variety of wire diameters may be accommodated for a given sized bore. The fuse holder 30 ~ .
~, .
~r 10451~9 is inserted into the fuse recess 8 until the end of the fuse wire 32 rests against the contact plate 26.
As best sho~m in Fig. 3, a pair of insulated leads 18 enter the plug housing 2 at a wire port 16 and enter grooves 14 which guide the lea~s 18 to the proper location. The leads 18 are forceably inserted in the yrooves 14 to cause the leads 18 to be frictionally held in place. For this reason, the grooves 14 provide strain relief so that the leads 18 camlot be forceably removed from the plug~ A contact 22 is secured to the conductors in the insulated leads 1~, either by crimp-ing or solderin~. The contacts 22 are held securely in place above the end of the fuse holder 30 by the yrooves 14. The contacts 22 are separated from each other by a projection 20 which, as will be explained hereinafter, also insures precise alignment of the cover 34 with the plug housing 2. The fuse holder 30 is easily re~oved from the plug housing 2 by forcing~
the ends of the pronys 24 into tne plug housing 2, tl~ereby forcing the fuse holder 30 out the other end of the plug housing 2 by the contact plate 26. A new fuse wire 32 is then cut to length and inserted through tne holes at each end ~ ~-of the fuse holder 30 and bent over each end. Finally, the ~ fuse holder 30 is reinserted in~ the fuse recess 8 after the end of the prong 24 has been-puIled back to its original ~positîon.
~ cover 34 is secured to thè plug housing 2 by~
screws~46 which extend through the screw holes lO~in the plug ~ housing 2 and engage the threaded bores~36 in the cover 34.
-~ The cove~34 contains an aligmnent slot 42 which receives the~
~alignment projection 18 on the plug housing 2 to insure that ;
~the rotational position between the cover 34 and the plug ;
housing~2 is correct. Further alignr,lent is provided by pro-jections~38 in the cover 34 which are inserted inta cylLndri-cal racesses 12 in axial alig~ment with the screw holes 10 1~45~
and tab 39, which fits into recess 41. The cover 34 further includes contact projections 40 which hold the contacts 22 against the ends or the fuse holder 30 to insure conduction between the contacts 22 and the Euse wire 32. The fuse holder 30 is formed from a resilient plastic which, when compressed between the contact projections 40 and the contact plates 26, forms an arc to maintain the ends of the fuse wires 32 in contact with the contact plates 26 and contacts 22.
The cover 34 further includes a pair of add-on plug slots 44 through which the prongs of another plug (not shown) can be inserted to enter the add-on plug recesses 6 and con-tac~ the plug tab 28, integrally formed from the prongs 24.
In this way, a plurality of plugs may be serviced from one socket. Note, however, that the add-on plugs will not be protected by the fuse of the present invention.
- Although the fuseable electrical plug of the present invention has been described as having a fuse in series with } each prong 24, adequate short circuit protection can beobtained by including a fuse in series with only one of the prongs. In this case, the non-fused prong will be identical to those in conventional use. Thus, it is to be understood that the present invention is not to be limited to the precise structure disclosed.
: .
~ ' .
~i ".
Claims (3)
1. A fuseable electrical plug comprising:
a non-conducting plug housing having therein a lat-erally spaced outer pair of longitudinal prong recesses and a central separated adjacent pair of longitudinal fuse recesses positioned side-by-side directly between and adjacent to said prong recesses, said fuse recesses each having a respective access opening located at one face of said housing, said housing including a non-conducting cover at said one face of the housing for closing said access openings, a pair of longitudinal conducting prongs in said prong recesses and projecting in parallel laterally spaced relation from an end face of said housing different from said one face, each of said prongs having a prong contact project-ing into the adjoining fuse recess at the end thereof adjacent said end face of the housing, a pair of elongated fuses with contacts at their opposite ends located in said fuse recesses and adapted to pass through said access openings when said cover is removed, the fuse contacts at one end of the fuses engaging respective of said prong contacts, a pair of conductor leads passing side-by-side ex-ternally through said housing adjacent the other ends of said fuse recesses which are located remote from said end face of the housing, said conductor leads having respective conductor contacts positioned in the fuse recesses at said other ends and arranged to be engaged by respective of the fuse contacts at the other end of the fuses, and means for holding the fuse contacts in operative engagement with the prong contacts and the conductor contacts.
a non-conducting plug housing having therein a lat-erally spaced outer pair of longitudinal prong recesses and a central separated adjacent pair of longitudinal fuse recesses positioned side-by-side directly between and adjacent to said prong recesses, said fuse recesses each having a respective access opening located at one face of said housing, said housing including a non-conducting cover at said one face of the housing for closing said access openings, a pair of longitudinal conducting prongs in said prong recesses and projecting in parallel laterally spaced relation from an end face of said housing different from said one face, each of said prongs having a prong contact project-ing into the adjoining fuse recess at the end thereof adjacent said end face of the housing, a pair of elongated fuses with contacts at their opposite ends located in said fuse recesses and adapted to pass through said access openings when said cover is removed, the fuse contacts at one end of the fuses engaging respective of said prong contacts, a pair of conductor leads passing side-by-side ex-ternally through said housing adjacent the other ends of said fuse recesses which are located remote from said end face of the housing, said conductor leads having respective conductor contacts positioned in the fuse recesses at said other ends and arranged to be engaged by respective of the fuse contacts at the other end of the fuses, and means for holding the fuse contacts in operative engagement with the prong contacts and the conductor contacts.
2. The fuseable electrical plug of claim 1, wherein said plug is adapted to receive the prongs of an add-on plug with the prongs of said add-on plug being electrically con-nected to respective of said prongs of said fuseable plug, said fuseable plug further including a pair of spaced apart slots in the face of said fuseable plug housing which is op-posite from said end face thereof for receiving the prongs of said add-on plug, and a respective add-on plug recess in said housing aligned with each of said slots and positioned adja-cent each conducting prong, said fuses being positioned be-tween the prongs of said fuseable plug and the prongs of said add-on plug.
3. A fuseable electrical plug according to claim 1 in which said means for holding the fuse contacts in operative engagement with the prong contacts and the conductor contacts comprises a portion of said cover located at said access open-ings of the fuse recesses.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US52045774A | 1974-11-04 | 1974-11-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1045189A true CA1045189A (en) | 1978-12-26 |
Family
ID=24072669
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA238,503A Expired CA1045189A (en) | 1974-11-04 | 1975-10-28 | Electrical power plug with series connected fuse |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS51101888A (en) |
| CA (1) | CA1045189A (en) |
| GB (1) | GB1497126A (en) |
-
1975
- 1975-10-28 CA CA238,503A patent/CA1045189A/en not_active Expired
- 1975-10-30 GB GB44971/75A patent/GB1497126A/en not_active Expired
- 1975-11-04 JP JP50132380A patent/JPS51101888A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS51101888A (en) | 1976-09-08 |
| GB1497126A (en) | 1978-01-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4080039A (en) | Fusable electrical plug | |
| US7893627B2 (en) | Light strands | |
| US6132257A (en) | Electrical socket device with overheating and overcurrent protection | |
| US5841337A (en) | Touch safe fuse module and holder | |
| US3723948A (en) | Electrical component | |
| US5989070A (en) | Bulb socket adapter | |
| US6753755B2 (en) | Electrical safety connector fuse | |
| US5429530A (en) | Cable connector including thermal fuse | |
| US7086892B2 (en) | Live circuit indicator for plugs and receptacles | |
| US6074244A (en) | Stringer of decorative lights | |
| US4400673A (en) | Thermal switch housing | |
| JPS58111281A (en) | Coupler connecting device | |
| US5004432A (en) | Electrical connector | |
| CA1045189A (en) | Electrical power plug with series connected fuse | |
| CA1042084A (en) | Wire terminal electrical contact | |
| DE59709883D1 (en) | Electrical connector | |
| US6780061B1 (en) | Multi-fusable electrical receptacle | |
| US4820197A (en) | Three-way switch system and adapter therefor | |
| GB2266810A (en) | Multi socket outlet assembly | |
| US2712121A (en) | Schmier | |
| US2997701A (en) | Plug-in cap with ground indicating light | |
| US2686856A (en) | Electric plug | |
| GB2266811A (en) | Switched socket outlet. | |
| CA1085011A (en) | Plural insulated electrical connectors | |
| US2180121A (en) | Decorative light for christmas trees and the like |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |
Effective date: 19951226 |