Patent US3873759A successfully refreshed from Google Patents.
US3873759A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical enclosure knockout structure
Assignee: Nelco Corp
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Filing: 1973-10-30
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Granted: 1975-03-25
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Expires: 1993-10-30
Abstract
Abstract An electrical enclosure having an aperture in one wall with a substantially planiform knockout tongue that projects from the wall structure of the enclosure adjacent the aperture, and disposed so that a surface thereof faces relatively outside of the enclosure at the aperture forming a portion of the outside surface of the enclosure. The outside surface of the enclosure has an identation formed therein, adjacent the juncture of the outer facing surface of the tongue with the wall structure. The indentation provides a line of stress concentration assuring that the tongue will fracture along the line when the tongue is bent inwardly into the interior of the enclosure. In one preferred embodiment the outer facing surface of the tongue is substantially coplanar with the inner-facing surface of the aforementioned said one wall with one peripheral edge of the tongue terminating along a line disposed substantially at the rim of the aperture. The peripheral edge of the tongue is inclined to the plane of the inner-facing surface of the one wall at said line, and forms a corner-like indentation with the inner-facing surface of the one wall, the apex of which is disposed substantially on the line. The indentation faces into the chamber so as to be accessible to the pointed tip of a prying tool introduced into the chamber through the front opening of the enclosure, and may be open to define a tool-receiving slot or may have a means at the apex thereof, at or between the line and the one edge of the one wall, which is readily pierceable by the tip of the tool, to enable the tool to be inserted in the aperture from the chamber, and applied against the outer facing surface of the tongue for removal of the tongue.
Inventors
- 👤 Edgar C Schindler
- 👤 John C Mceachron
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:45
CPC Classifications
H; H02; H02G; H02G3/00; H02G3/02; H02G3/08; H02G3/081; H02G3/083; H02G3/085
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
232 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween, which together define a chamber within the box that opens to the ambient surroundings of the box through the front thereof, an aperture in one of the aforesaid walls, and a substantially planiform knockout tongue that projects from the wall structure adjacent the aperture, and is disposed so that a surface thereof faces relatively outside of the box at the aperture, and forms a portion of the outside surface of the box, said outer facing surface of the tongue extending in substantially coplanar relationship with the inside surface of the aforesaid one wall, and terminating at one edge of the tongue along a line disposed in a region between that portion of the rim of the aperture formed by one edge of the one wall and an area of said aperture inwardly from said rim, said region including the said rim portion of the aperture, said one edge of the tongue being inclined to the plane of the inside surface of the one wall at the line, and forming a corner-like indentation therewith, the apex of which is disposed on the line, said indentation facing into the chamber so as to be accessible to the pointed tip of a prying tool introduced into the chamber through the front opening of the box.
Claim 2
Dependent Claim
232 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween, which together define a chamber within the box that opens to the ambient surroundings of the box through the front thereof, an aperture in one of the aforesaid walls, and a substantially planiform knockout tongue that projects from the wall structure adjacent the aperture, and is disposed so that a surface thereof faces relatively outside of the box at the aperture, and forms a portion of the outside surface of the box, said outer facing surface of the tongue extending in substantially coplanar relationship with the inside surface of the aforesaid one wall, and terminating at one edge of the tongue along a line disposed in a region between that portion of the rim of the aperture formed by one edge of the one wall and an area of said aperture inwardly from said rim, said region including the said rim portion of the aperture, said one edge of the tongue being inclined to the plane of the inside surface of the one wall at the line, and forming a corner-like indentation therewith, the apex of which is disposed on the line, said indentation facing into the chamber so as to be accessible to the pointed tip of a prying tool introduced into the chamber through the front opening of the box.
Claim 3
Dependent Claim
41 words
The electrical outlet box according to claim 1 wherein the one edge of the tongue is spaced apart from the one edge of the one wall at the apex of the indentation, so that there is a narrow gap formed therebetween.
Claim 4
Dependent Claim
31 words
The electrical outlet box according to claim 2 wherein the gap is open to the chamber and the aperture for insertion of the tip of the tool therethrough into the aperture.
Claim 5
Dependent Claim
33 words
An electrical outlet box according to claim 2, including a thin flashing formed across the gap, which operates to close the gap but which is readily pierceable by the tip of the tool.
Claim 6
Dependent Claim
44 words
The electrical outlet box according to claim 2 wherein the tongue is spaced apart from the one edge of the one wall in the plane of the inside surface thereof, so that the gap has a dimensional component in the direction of the plane.
Claim 7
Dependent Claim
33 words
The electrical outlet box according to claim 5 including a thin flashing formed across the gap, which operates to close the gap but which is readily pierceable by the tip of the tool.
Claim 8
Dependent Claim
64 words
The electrical outlet box according to claim 2 wherein there is a thin flashing formed across the gap, and the one edge of the one wall has a rabbet about the inner periphery thereof, and wherein the tongue projects across the interface between the rabbet and the chamber, so as to closely approach the inner peripheral shoulder of the rabbet to support the flashing.
Claim 9
Dependent Claim
21 words
The electrical outlet box according to claim 7 wherein the rabbet is disposed along the projecting side edges of the tongue.
Claim 10
Dependent Claim
26 words
The electrical outlet box according to claim 2 wherein there is a thin flashing formed across the gap at the projecting end edge of the tongue.
Claim 11
Dependent Claim
27 words
The electrical outlet box according to claim 9 wherein the gap along each projecting side edge of the tongue is open to the chamber and the aperture.
Claim 12
Dependent Claim
32 words
The electrical outlet box according to claim 1 wherein the one edge of the tongue is disposed at an acute angle to the plane of the inside surface of the one wall.
Claim 13
Dependent Claim
32 words
The electrical outlet box according to claim 1 wherein the one edge of the tongue iS disposed at a right angle to the plane of the inside surface of the one wall.
Claim 14
Dependent Claim
20 words
The electrical outlet box according to claim 1 wherein the one edge of the tongue is arcuate in plan configuration.
Claim 15
Dependent Claim
20 words
The electrical outlet box according to claim 1 wherein the one edge of the tongue is rectangular in plan configuration.
Claim 16
Dependent Claim
36 words
The electrical outlet box according to claim 1 wherein the aperture is disposed in a corner of the box defined by the one wall and an adjoining wall which coterminates with the tongue at the aperture.
Claim 17
Dependent Claim
175 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween, which together define a chamber within the box that opens to the ambient surroundings of the box through the front thereof, an aperture in one of the aforesaid walls, and a substantially planiform knockout tongue that projects from the wall structure adjacent the aperture, and is disposed so that a surface thereof faces relatively outside of the box at the aperture, and forms a portion of the outside surface of the box, said outside surface of the box having a surface discontinuity thereon adjacent the juncture of the outer facing surface of the tongue with the wall structure, whereby the tongue fractures along a line intersecting the discontinuity, when a force is applied to the tongue, crosswise thereof, in the direction of the chamber from the aperture, said tongue including an inner facing surface which faces inside of said box, said inner facing surface having a rib raised thereon which extends transversely of the tongue.
Claim 18
Dependent Claim
175 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween, which together define a chamber within the box that opens to the ambient surroundings of the box through the front thereof, an aperture in one of the aforesaid walls, and a substantially planiform knockout tongue that projects from the wall structure adjacent the aperture, and is disposed so that a surface thereof faces relatively outside of the box at the aperture, and forms a portion of the outside surface of the box, said outside surface of the box having a surface discontinuity thereon adjacent the juncture of the outer facing surface of the tongue with the wall structure, whereby the tongue fractures along a line intersecting the discontinuity, when a force is applied to the tongue, crosswise thereof, in the direction of the chamber from the aperture, said tongue including an inner facing surface which faces inside of said box, said inner facing surface having a rib raised thereon which extends transversely of the tongue.
Claim 19
Dependent Claim
202 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween, which together define a chamber within the box that opens to the ambient surroundings of the box through the front thereof, an aperture in one of the aforesaid walls, and a substantially planiform knockout tongue that projects from the wall structure adjacent the aperture, and is disposed so that a surface thereof faces relatively outside of the box at the aperture, and forms a portion of the outside surface of the box, said outside surface of the box having an indentation formed therein, adjacent the juncture of the outer facing surface of the tongue with the wall structure, whereby the tongue fractures along a line intersecting the indentation, when a force is applied to the tongue, crosswise thereof, in the direction of the chamber from the aperture, said tongue including an inner facing surface which faces inside of said box at the chamber and forms a corner with the wall structure adjacent the juncture of the tongue with said wall, one of said inner and outer facing surfaces of the tongue having a rib raised thereon which extends transversely of said tongue.
Claim 20
Dependent Claim
202 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween, which together define a chamber within the box that opens to the ambient surroundings of the box through the front thereof, an aperture in one of the aforesaid walls, and a substantially planiform knockout tongue that projects from the wall structure adjacent the aperture, and is disposed so that a surface thereof faces relatively outside of the box at the aperture, and forms a portion of the outside surface of the box, said outside surface of the box having an indentation formed therein, adjacent the juncture of the outer facing surface of the tongue with the wall structure, whereby the tongue fractures along a line intersecting the indentation, when a force is applied to the tongue, crosswise thereof, in the direction of the chamber from the aperture, said tongue including an inner facing surface which faces inside of said box at the chamber and forms a corner with the wall structure adjacent the juncture of the tongue with said wall, one of said inner and outer facing surfaces of the tongue having a rib raised thereon which extends transversely of said tongue.
Claim 21
Dependent Claim
118 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween defining a chamber within said box open through the front thereof, an aperture formed in one of said walls, a planiform knockout tongue removably mounted across said aperture to provide a substantial barrier to communication therethrough, the otuer facing surface of said tongue being substantially coplanar with the inner facing surface of said wall in which said aperture is formed, a forward edge of said tongue facing the open front of said box, said forward edge being disposed at a right angle to the plane of the inside surface of said wall in which said aperture is formed.
Claim 22
Dependent Claim
118 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween defining a chamber within said box open through the front thereof, an aperture formed in one of said walls, a planiform knockout tongue removably mounted across said aperture to provide a substantial barrier to communication therethrough, the otuer facing surface of said tongue being substantially coplanar with the inner facing surface of said wall in which said aperture is formed, a forward edge of said tongue facing the open front of said box, said forward edge being disposed at a right angle to the plane of the inside surface of said wall in which said aperture is formed.
Claim 23
Dependent Claim
118 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween defining a chamber within said box open through the front thereof, an aperture formed in one of said walls, a planiform knockout tongue removably mounted across said aperture to provide a substantial barrier to communication therethrough, the outer facing surface of said tongue being substantially coplanar with the inner facing surface of said wall in which said apertuRe is formed, a forward edge of said tongue facing the open front of said box, said forward edge being disposed at an acute angle to the plane of the inside surface of said wall in which said aperture is formed.
Claim 24
Dependent Claim
118 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween defining a chamber within said box open through the front thereof, an aperture formed in one of said walls, a planiform knockout tongue removably mounted across said aperture to provide a substantial barrier to communication therethrough, the outer facing surface of said tongue being substantially coplanar with the inner facing surface of said wall in which said apertuRe is formed, a forward edge of said tongue facing the open front of said box, said forward edge being disposed at an acute angle to the plane of the inside surface of said wall in which said aperture is formed.
Claim 25
Dependent Claim
138 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween defining a chamber within said box open through the front thereof, an aperture formed in one of said walls, a planiform knockout tongue removably mounted across said aperture to provide a substantial barrier to communication therethrough, the outer facing surface of said tongue being substantially coplanar with the inner facing surface of said wall in which said aperture is formed, a forward edge of said tongue facing the open front of said box, said forward edge of said tongue and the corresponding edge of said aperture being spaced apart to provide a gap therebetween coplanar with the outer facing surface of said tongue and with the inner facing surface of said wall in which said aperture is formed.
Claim 26
Dependent Claim
138 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween defining a chamber within said box open through the front thereof, an aperture formed in one of said walls, a planiform knockout tongue removably mounted across said aperture to provide a substantial barrier to communication therethrough, the outer facing surface of said tongue being substantially coplanar with the inner facing surface of said wall in which said aperture is formed, a forward edge of said tongue facing the open front of said box, said forward edge of said tongue and the corresponding edge of said aperture being spaced apart to provide a gap therebetween coplanar with the outer facing surface of said tongue and with the inner facing surface of said wall in which said aperture is formed.
Claim 27
Dependent Claim
177 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween defining a chamber within said box open through the front thereof, an aperture formed in one of said walls, a planiform knockout tongue removably mounted across said aperture to provide a substantial barrier to communication therethrough, the outer facing surface of said tongue lying in a plane spaced inwardly from and substantially parallel to the plane of the inner surface of said wall in which said aperture is formed, a forward edge of said tongue facing the open front of said box, a gap between said inner facing surface of said wall and said outer facing surface of said tongue along said forward edge thereof, the width of said gap between said inner and outer facing surfaces being at least as great as the corresponding tip dimension of a prying tool for entry therein, including a thin flashing formed across said gap for closure thereof, said flashing being readily pierceable by the tip of said prying tool.
Claim 28
Dependent Claim
177 words
In an electrical outlet box having a wall structure defining front to rear walls and a back wall interconnected therebetween defining a chamber within said box open through the front thereof, an aperture formed in one of said walls, a planiform knockout tongue removably mounted across said aperture to provide a substantial barrier to communication therethrough, the outer facing surface of said tongue lying in a plane spaced inwardly from and substantially parallel to the plane of the inner surface of said wall in which said aperture is formed, a forward edge of said tongue facing the open front of said box, a gap between said inner facing surface of said wall and said outer facing surface of said tongue along said forward edge thereof, the width of said gap between said inner and outer facing surfaces being at least as great as the corresponding tip dimension of a prying tool for entry therein, including a thin flashing formed across said gap for closure thereof, said flashing being readily pierceable by the tip of said prying tool.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |