1. Field of the Invention
The present invention relates to a socket lock for an ornament bulb, which comprises a latch and a retaining groove to lock a bulb base in a socket.
2. Description of Related Art
A conventional method of joining an ornament bulb to a socket is a simple press joint. However, the disadvantage of the press joint is that the bulb may be loosened from the socket, because of thermal deformation caused by temperature changes.
To rectify the above defect, a lock joint was developed that included a latch and corresponding attachment block. The latch can be folded to lock with the attachment block. However, the production costs increase dramatically with the requisite manual labor required to fold and lock the latch with the attachment block for the great number of bulbs.
As shown in FIG. 11, a wedge joint at the junction of the socket (90) and the bulb base (80) includes a wedge (82) and two corresponding semicircular attachment blocks (92). The wedge (82) is integrally formed at the end of a horizontal radial post integrally formed at the top of the bulb base (80). The two attachment blocks (92) define a gap (94) therebetween, and each has a flat bottom surface attached on the top of the socket (90). The width of the gap (94) is slightly smaller than that of the upper end of the wedge (82).
To install the bulb base (80) into the socket (90), the wedge (82) is pushed into the gap (94) till the upper edge of the wedge (82) abuts the bottom edge of the attachment block (92). Then, the attachment blocks (92) retain the wedge (82) therebetween and thereunder.
The wedge joint is easy to assemble, but still there is a problem of replacement, especially when replacement of a failed bulb is necessary. Therefore, a more advanced joint method needs to be developed.