Snap-in means for mounting electrical devices or the like in a support panel aperture

In a toggle switch assembly adapted to be snap-in mounted from the back of a panel through a hole in the panel and including an insulated base housing switch contacts, a switch frame covering the base, and a pivotal toggle lever for actuating the switch contacts, wherein the improvement comprises

• an elongated bushing extending outwardly from said switch frame and pivotally supporting said toggle lever, said bushing having an outer end portion adapted to be inserted into the panel mounting hole,
• an annular groove in said bushing outer end portion,
• retainer means comprising a split ring which is slidably disposed in said bushing groove, which is radially compressible and expandable in the plane thereof within said bushing groove between a normally expanded position where its outer dimension is greater than the dimension of the panel mounting hole and a compressed position where it can pass through the hole, and which has a beveled leading edge portion which engages the back rim of the hole and serves to cam said ring to said compressed position as said bushing outer end portion is inserted into the hole during mounting, said ring returning to its normally expanded position, where at least a portion thereof overlies the front of the support panel in the area surrounding the mounting hole, after said bushing outer end portion has been inserted through the mounting hole,
• a plurality of circumferentially spaced spring fingers extending inwardly from the inner periphery of said ring and bearing against the inner wall of said bushing groove to evenly space said ring from said groove inner wall when said ring is in said expanded position,
• an annular undercut located in the trailing edge portion of said ring and including a radially extending ledge, and
• a coil spring encircling said bushing with one end bearing against said switch frame and the opposite end engaging said ring ledge prior to mounting.
• whereby said opposite end of said spring is disengaged from said ring ledge and bears against the back of the support panel as said bushing outer end portion is inserted through the panel mounting hole during mounting so that said spring thereafter urges said bushing in an axial direction away from the support panel and thereby holds said ring in tight engagement with the front of the support panel.

The snap-in mounting means for a device adapting the device to be mounted from the back of and through a hole in a support panel to secure the device to the panel so that part of the device is accessible from the front of the panel comprising

• An elongated bushing carrying the accessible part of the device and having an outer end portion to be received in the panel mounting hole, said bushing outer end portion including an annular groove,
• retainer means comprising a split ring which is slidably disposed in said bushing groove, which is radially compressible and expandable within said bushing groove between a normally expanded position where its outer dimension is larger than the dimension of the panel mounting hole and a compressed position where it can pass through the panel mounting hole, and which has a trailing edge portion and a bevelled leading edge portion which engages the back rim of the panel mounting hole and serves to cam said ring to said compressed position as said bushing outer edge portion is inserted into the hole during mounting, said ring returning to its normally expanded position, where at least a portion thereof overlies the front of the support panel in the area surrounding the mounting hole, after said bushing outer and portion has been inserted through the mounting hole,
• means for centering said retainer means with respect to the panel mounting hole comprising an annular undercut located in the trailing edge portion of said ring providing a coaxial surface of reduced dimension which is pressed against the inner wall of the panel mounting hole by self expansion of the ring, and
• biasing means adapted to urge said bushing in an axial direction away from the back of the support panel and thereby hold said retainer means in tight engagement with the front of the support panel after mounting.