US3754202A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Grounding plug
Assignee: Individual
•
Filing: 1971-09-30
•
Granted: 1973-08-21
•
Expires: 1991-09-30
Abstract
Abstract An electrical connector plug for providing connection to two or more sides of a circuit with conventional prong means and having a grounding prong which can be inserted into a grounding socket in a receptacle. The grounding prong is provided with a protruding sensing finger that is in an inactive position when the receptacle has a grounding socket, but if there is no grounding socket present, then the protruding sensing finger strikes a solid surface of the receptacle and moves backward to trigger a latch means that unlatches the grounding prong and allows it to be pushed back into the body of the plug, allowing the circuit contact prongs to enter the receptacle''s live sockets to complete the electrical circuit. In order to prevent accidental triggering of this sensing finger by finger pressure on the end of the sensing finger or by force exerted on the axially-shiftable portion of the grounding prong, which might overcome the safety feature of the grounding prong, by finger pressure on the end of the grounding prong, the mechanism may be safetied by an arrangement for the latch means, such that pressure applied to the protruding prong by a yieldable means such as a finger, or other yieldable portion of the body, will push the entire grounding prong back toward the plug but will prevent the protruding sensor finger from triggering the lever, therefore preventing the retraction of the grounding prong into the plug. As an additional feature, the grounding prong can be designed so that it will never be completely retracted into the plug and a grounding plate is provided for attachment to a receptacle so that when the grounding prong is used in conjunction with a receptacle not having a matching grounding socket, the retracted grounding prong will still contact the grounding plate and provide for the safe grounding of the circuit.
Inventors
- 👤 R Nelson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:30
CPC Classifications
H; H01; H01R; H01R27/00
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
237 words
An electrical connector plug which comprises: a. a body member, said body member having a longitudinal axis; b. a plurality of electrically conductive contact prong members, said electrical contact prong members being mounted to said body member in position to protrude from said body member parallel to said longitudinal axis, said electrical contact prong members being adapted to be attached to electrical conductors for transmission of electrical current; c. at least one grounding prong member, said grounding prong member comprising an axially shiftable conductive element being carried by the body member, and shiftable within the body member, said grounding prong member being adapted to protrude axially from and to be retracted into said body member, said grounding prong member being adapted to be attached to a grounding conductor; d. latch means movably mounted to the plug selectively to permit or to limit axial movement of the axially shiftable conductive element; e. bias spring means, said bias spring means biasing the axially shiftable conductive element toWard its protruding position; f. sensing finger means movably mounted to the plug and so disposed and arranged relative to the latch means as to move the latch means to permit axial movement of the axially shiftable conductive element into the body member when said sensing finger undergoes an axial force, said sensing finger means projecting beyond the end of said axially shiftable conductive element unless it is retracted by said axial force.
Claim 2
Dependent Claim
237 words
An electrical connector plug which comprises: a. a body member, said body member having a longitudinal axis; b. a plurality of electrically conductive contact prong members, said electrical contact prong members being mounted to said body member in position to protrude from said body member parallel to said longitudinal axis, said electrical contact prong members being adapted to be attached to electrical conductors for transmission of electrical current; c. at least one grounding prong member, said grounding prong member comprising an axially shiftable conductive element being carried by the body member, and shiftable within the body member, said grounding prong member being adapted to protrude axially from and to be retracted into said body member, said grounding prong member being adapted to be attached to a grounding conductor; d. latch means movably mounted to the plug selectively to permit or to limit axial movement of the axially shiftable conductive element; e. bias spring means, said bias spring means biasing the axially shiftable conductive element toWard its protruding position; f. sensing finger means movably mounted to the plug and so disposed and arranged relative to the latch means as to move the latch means to permit axial movement of the axially shiftable conductive element into the body member when said sensing finger undergoes an axial force, said sensing finger means projecting beyond the end of said axially shiftable conductive element unless it is retracted by said axial force.
Claim 3
Dependent Claim
20 words
A device according to claim 1 in which said sensing finger means is disposed adjacent to said grounding prong member.
Claim 4
Dependent Claim
67 words
A device according to claim 1 in which said grounding prong member includes a conductive outer tubular member fixed to said body member, said axially shiftable conductive element being slidably mounted within said outer tubular member, said axially shiftable conductive element being adapted to protrude from said body member parallel to said longitudinal axis, the outer tubular member being adapted to be attached to a grounding conductor.
Claim 5
Dependent Claim
54 words
A device according to claim 3 in which the axially shiftable tubular element includes a bore through which the sensing finger means passes, and in which it is axially shiftable, the biasing on the sensing finger means biasing one of its ends to protrude beyond the respective end of the axially shiftable conductive element.
Claim 6
Dependent Claim
78 words
A device according to claim 4 in which the latch means is pivotally mounted to the axially shiftable conductive element, in which the outer tubular member includes an axially extending slot, and in which the latch means includes an upstanding arm adapted to enter said last-named slot and engage said wall of said axial passage to prevent retraction of the axially shiftable conductive element except when the sensing finger means is retracted into the axially shiftable conductive element.
Claim 7
Dependent Claim
21 words
A device according to claim 5 in which the bias spring means also biases the latch means toward its inter-engaged position.
Claim 8
Dependent Claim
42 words
A device according to claim 5 in which the said last-named slot is of such length as to permit a limited, but not total, amount of retraction of the axially shiftable conductive element even when the sensing finger means is not retracted.
Claim 9
Dependent Claim
37 words
A device according to claim 3 in which said latch means is formed as a bell-crank lever means adapted to lock said axially shiftable conductive element in a protruding axial position with respect to said body member.
Claim 10
Dependent Claim
44 words
A device according to claim 3 in which cap plug means of electrically conductive material is fixedly inserted in said axially shiftable conductive element, said cap plug means being adapted to enter an electrical receptacle as a leading part of said grounding prong member.
Claim 11
Dependent Claim
23 words
A device according to claim 9 in which said cap plug means is constructed of a magnetically permeable material having electrically conductive properties.
Claim 12
Dependent Claim
22 words
A device according to claim 9 in which said cap plug means is constructed of a magnetized material having eletrically conductive properties.
Claim 13
Dependent Claim
41 words
A device according to claim 9 in which said cap plug means has an axial bore therethrough, said bore being adapted to slidably mount said sensing finger means, said sensing finger means being adapted to protrude from said cap plug means.
Claim 14
Dependent Claim
172 words
A device according to claim 8 in which said outer tubular member and said axially shiftable conductive element have co-registering axially extending slots, and the bell-crank lever means includes an upstanding arm, said slot in said outer tubular member being aligned with said slot in said axially shiftable conductive element, said slots being adapted to engage the upstanding lever arm of said bell-crank lever means for locking said axially shiftable conductive element in a protruding position with respect to said body member, said spring bias means being adapted to prevent said sensing finger means from releasing said bell-crank lever means when said sensing finger means is contacted by a fleshlike resilient material whereby said fleshlike resilient material will yield until contact is made with said grounding prong to push back said axially shiftable conductive element against said spring bias means thereby to lock said upstanding arm of said bell-crank lever means in said slot of said outer tubular member to prevent sliding of said axially shiftable conductive element into said body member.
Claim 15
Dependent Claim
276 words
In combination: an electrical receptacle having sockets for receiving electrical conductor prongs, an electrical plug, and interconnecting grounding means, said combination comprising: grounding plate means mounted to the electrical receptacle and having a conductive contact surface facing away from the sockets; a plug body member, said plug body member having a longitudinal axis; a plurality of electrically conductive contact prong members, said electrical contact prong members being mounted to said body member and protruding from said body member parallel to said longitudinal axis, said electrical contact prong members being adapted to be attached to electrical conductors for transmission of electrical current; at least one grounding prong member, said grounding prong member comprising an axially shiftable conductive element being carried by the body member, and shiftable in and embraced by the wall of an axial passage in the body member, said grounding prong member being adapted to protrude axially from and to be retracted into said body member, said grounding prong member being adapted to be attached to a grounding conductor; latch means movably mounted to the plug selectively to permit or to limit axial movement of the axially shiftable conductive element; bias spring means, said bias spring means biasing the axially shiftable conductive element toward its protruding position; sensing finger means movably mounted to the plug and so disposed and arranged relative to the latch means as to move the latch means to permit axial movement of the axially shiftable conductive element into the body member when said sensing finger undergoes an axial force, said sensing finger means projecting beyond the end of said axially shiftable conductive element unless it is retracted by said axial force.
Claim 16
Dependent Claim
276 words
In combination: an electrical receptacle having sockets for receiving electrical conductor prongs, an electrical plug, and interconnecting grounding means, said combination comprising: grounding plate means mounted to the electrical receptacle and having a conductive contact surface facing away from the sockets; a plug body member, said plug body member having a longitudinal axis; a plurality of electrically conductive contact prong members, said electrical contact prong members being mounted to said body member and protruding from said body member parallel to said longitudinal axis, said electrical contact prong members being adapted to be attached to electrical conductors for transmission of electrical current; at least one grounding prong member, said grounding prong member comprising an axially shiftable conductive element being carried by the body member, and shiftable in and embraced by the wall of an axial passage in the body member, said grounding prong member being adapted to protrude axially from and to be retracted into said body member, said grounding prong member being adapted to be attached to a grounding conductor; latch means movably mounted to the plug selectively to permit or to limit axial movement of the axially shiftable conductive element; bias spring means, said bias spring means biasing the axially shiftable conductive element toward its protruding position; sensing finger means movably mounted to the plug and so disposed and arranged relative to the latch means as to move the latch means to permit axial movement of the axially shiftable conductive element into the body member when said sensing finger undergoes an axial force, said sensing finger means projecting beyond the end of said axially shiftable conductive element unless it is retracted by said axial force.
Claim 17
Dependent Claim
20 words
A combination according to claim 14 in which said sensing finger means is disposed adjacent to said grounding prong member.
Claim 18
Dependent Claim
67 words
A combination according to claim 14 in which said grounding prong member includes a conductive outer tubular member fixed to said body member, said axially shiftable conductive element being slidably mounted within said outer tubular member, said axially shiftable conductive element being adapted to protrude from said body member parallel to said longitudinal axis, said grounding prong member being adapted to be attached to a grounding conductor.
Claim 19
Dependent Claim
54 words
A combination according to claim 16 in which the axially shiftable tubular element includes a bore through which the sensing finger means passes, and in which it is axially shiftable, the biasing on the sensing finger means biasing one of its ends to protrude beyond the respective end of the axially shiftable conductive element.
Claim 20
Dependent Claim
78 words
A combination according to claim 17 in which the latch means is pivotally mounted to the axially shiftable conductive element, in which the outer tubular member includes an axially extending slot, and in which the latch means includes an upstanding arm adapted to enter said last-named slot and engage said wall of said axial passage to prevent retraction of the axially shiftable conductive element except when the sensing finger means is retracted into the axially shiftable conductive element.
Claim 21
Dependent Claim
21 words
A combination according to claim 18 in which the bias spring means also biases the latch means toward its inter-engaged position.
Claim 22
Dependent Claim
42 words
A combination according to claim 18 in which the said last-named slot is of such length as to permit a limited, but not total, amount of retraction of the axially shiftable conductive element even when the sensing finger means is not retracted.
Claim 23
Dependent Claim
37 words
A combination according to claim 16 in which said latch means is formed as a bell-crank lever means adapted to lock said axially shiftable conductive element in a protruding axial position with respect to said body member.
Claim 24
Dependent Claim
44 words
A combination according to claim 16 in which cap plug means of electrically conductive material is fixedly inserted in said axially shiftable conductive element, said cap plug means being adapted to enter an electrical receptacle as a leading part of said grounding prong member.
Claim 25
Dependent Claim
23 words
A combination according to claim 22 in which said cap plug means is constructed of a magnetically permeable material having electrically conductive properties.
Claim 26
Dependent Claim
23 words
A combination according to claim 22 in which said cap plug means is constructed of a magnetized material having electrically conductive properties. said
Claim 27
Dependent Claim
40 words
A combination according to claim 22 in which cap plug means has an axial bore therethrough, said bore being adapted to slidably mount said sensing finger means, said sensing finger means being adapted to protrude from said cap plug means.
Claim 28
Dependent Claim
172 words
A combination according to claim 21 in which said outer tubular member and said axially shiftable conductive element have co-registering axially extending slots, and the bell-crank lever means includes an upstanding area, said slot in said outer tubular member being aligned with said slot in said axially shiftable conductive element, said slots being adapted to engage the upstanding lever arm of said bell-crank lever means for locking said axially shiftable conductive element in a protruding position with respect to said body member, said spring bias means being adapted to prevent said sensing finger means from releasing said bell-crank lever means when said sensing finger means is contacted by a fleshlike resilient material whereby said fleshlike resilient material will yield until contact is made with said grounding prong to push back said axially shiftable conductive element against said spring bias means thereby to lock said upstanding arm of said bell-crank lever means in said slot of said outer tubular member to prevent sliding of said axially shiftable conductive element into said body member.
Claim 29
Dependent Claim
20 words
A combination according to claim 14 in which said grounding plate means is constructed of magnetically permeable electrically conductive material.
Claim 30
Dependent Claim
19 words
A combination according to claim 14 in which said grounding plate means is constructed of magnetized electrically conductive material.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-20 | 1977-02-19 | 1977-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-20 | 1981-02-19 | 1981-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-20 | 1985-02-19 | 1985-08-21 | $7700.00 | Window Closed / Lapsed |