초록 ▼

A knockout arrangement for an electrical junction box includes a housing having at least one side wall being substantially planar, a pair of spaced apart first knockout structures on the side wall with the first knockout structures defining a first circular knockout and a second annular knockout sur

A knockout arrangement for an electrical junction box includes a housing having at least one side wall being substantially planar, a pair of spaced apart first knockout structures on the side wall with the first knockout structures defining a first circular knockout and a second annular knockout surrounding and containing the first circular knockout, the first and second knockouts having centers spaced apart such that the second knockout is defined in eccentric relation to the first knockout and the first and second knockouts of each knockout structure are adapted to be selectively removed to create a trade size opening for passage of a conduit of either of two sizes through the side wall, and a second knockout structure disposed on the side wall between and spaced apart from the first knockout structures and containing only the first knockout. The housing further has a plurality of the side walls with an opposing pair of the side walls having a plurality of spaced apart coplanar mounting ears respectively disposed adjacent opposite ends of the opposing side walls for attachment of a cover plate having corresponding mounting holes or slots to the housing for mounting of a dynamic load to the cover plate.

대표청구항 ▼

[ What is claimed is:] [1.] An electrical junction box defined by a back wall having four planar side walls connected to and extending outwardly from said back wall and a knockout arrangement on at least one of said side walls for accepting two different diameter size conduits, said knockout arrange

[ What is claimed is:] [1.] An electrical junction box defined by a back wall having four planar side walls connected to and extending outwardly from said back wall and a knockout arrangement on at least one of said side walls for accepting two different diameter size conduits, said knockout arrangement comprising:(a) a pair of first knockout structures being spaced apart along said at least one side wall, each of said first knockout structures including a first circular knockout and a second annular knockout completely surrounding said first circular knockout and having regions of maximum and minimum width angularly spaced from each other on opposite sides of said first knockout along a diameter of said second knockout, said first and second knockouts having centers spaced apart such that said second knockout is defined in an eccentric relation to said first knockout whereby each of said first and second knockouts can be selectively removed to create an opening for accepting a conduit of either of said two different diameter size conduits; and(b) a second knockout structure disposed on said at least one side wall and being spaced from said first knockout structures and containing only said first knockout;(c) said first and second knockouts of said first and second knockout structures are respectively defined by areas of weakness along first and second substantially circular punch lines, said first punch line being completely contained within and spaced from said second punch line;(d) said first knockout including a first bridge member interrupting said first punch line and constituting the sole junction between said first knockout and said second knockout, said first bridge being disposed within said region of maximum width of said second knockout;(e) said second knockout including a second bridge member interrupting said second punch line and a pair of pseudo-bridge members which do not interrupt said second punch line, said second bridge being disposed within said region of maximum width of said second knockout and said pair of pseudo-bridge members being disposed within said region of minimum width of said second knockout;(f) said second bridge member and said pair of pseudo-bridge members constituting a junction between said second knockout and said at least one side wall and providing a first retention strength greater than a second retention strength provided by said first bridge member for said first knockout such that said first knockout can be removed from said second knockout without said second knockout being removed from said at least one side wall.