Abstract: A flashlight bulb of the type having a sealed envelope from which two pins extend in parallel relationship can be removably mounted in a PR-type base by the use of an insert that fits within the PR-type base and that includes, in addition to the holes for the pins, balls that are urged laterally against the pins by compression springs within the insert. The balls establish electrical contact with the pins and are connected by conductors to the terminals of the PR-type base.
Abstract: A stiffener is bonded to the bead of the flashlight bulb and extends along and between the pins. The stiffener includes indexing surfaces for use in laterally positioning the stiffener and flashlight bulb. An insert is bonded into a PR base so that the exposed end of the insert is a prescribed axial distance from an axial reference surface of the PR base. The insert includes a first set of indexing surfaces that center the insert in the PR base. The insert also includes a second set of indexing surfaces for receiving and centering the indexing surfaces of the stiffener with respect to the insert. The stiffener is inserted into the insert far enough that the bead of the flashlight bulb contacts the exposed end of the insert, thereby assuring that the filament is a prescribed distance from the axial reference surface of the PR base. A tight sliding fit between the stiffener and the insert assures that the stiffener is centered within the insert, which in turn is centered within the PR base.
Abstract: An improved flashlight bulb in which excessive wandering of the glass envelope with respect to the filament during the sealing phase of manufacture is prevented by fusing a spacer bead to the wires supporting the filament, the diameter of the spacer bead being only slightly less than the inside diameter of the glass envelope, so that lateral movement of the glass envelope with respect to the filament is limited by the spacer bead. In the preferred embodiment, the spacer bead is an elongated bead that extends from approximately 0.040 inch of the filament to the base of the bulb. In an alternative embodiment, the wires within the bulb are fused to a sealing bead which is spaced from the spacer bead. In yet another alternative embodiment, a stack of beads extends from a point near the filament to the base of the flashlight bulb.