Socket lock for ornament bulbs

A socket lock for ornament bulbs between the bulb base and socket includes a T-shaped latch and two attachment blocks. The T-shaped latch includes a tongue and a tapered lock. When the bulb base is inserted into the socket, the lock of the latch slides over the attachment block and fills the gap to lock the bulb base and the socket together. Particularly, the socket lock is easily released by breaking the T-shaped latch from the attachment blocks and pulling the bulb base out of the socket.

BACKGROUND OF THE INVENTION
 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.
 SUMMARY OF THE INVENTION
 The main object of the present invention is to provide a lock joint between
 an ornamental bulb and a socket, which comprises a T-shaped latch and two
 attachment blocks respectively on the bulb base and the socket at the
 joint. When the bulb base is inserted into the socket, the latch beside
 the base or socket slides over the fixture blocks being inserted into a
 corresponding gap, which is defined between the two attachment blocks, and
 the bulb is lock therein. When the bulb needs to be released from the
 socket, a person can easily detach the T-shaped latch from the attachment
 blocks and pull the bulb out of the socket.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
 As shown in FIG. 1, a lock joint in accordance with the present invention
 includes a bulb base (10) and a socket (20). The bulb base (10) has a
 circular top end (16) integrally formed with a radial extending and
 downward latch (12). The socket (20) integrally forms two radial extending
 attachment blocks (24) that define a gap (22) there between for receiving
 the latch (12) therein.
 The latch (12) includes a tongue (120) and a lock (122). Wherein the tongue
 (120) has a horizontal end integrally formed with the top end of the base
 (10) and a vertical end integrally formed with the lock (122) that is
 wider that the tongue (120). Thus the latch (12) has the shape of an
 inverted T. The lock (122) is tapered to have an interior inclined surface
 (14), and the top surface of the fixture block (24) also forms a taper
 (26). Accordingly the latch (12) can slip over the attachment block (24)
 by pressing it downward.
 The gap (22) is wider than the tongue (120) of the latch (12), but narrower
 than the lock (122). The vertical length of the tongue (120) is long
 enough to let the upper edge of the lock (122) to be positioned under the
 lower edge of the attachment block (24) when the lock (122) and the
 attachment block (24) are joined together.
 To assemble the bulb, a worker can easily insert the bulb base (10) into
 the socket (20) by pressing the latch (12) into the gap (22). Due to the
 flexibility of the material, the lock (122) slides over the attachment
 block (24), the tongue (120) fills the gap (22), and the lock (122)
 catches the lower edge of the attachment block (24). In such a way, the
 bulb base (10) is positively held in the socket (20) by the lock joint.
 Moreover, when a bulb needs to be replaced, it is easy to release them by
 breaking the lock (122) from the attachment block (24) and pulling bulb
 base (10) out of the socket (20).
 The attachment block (24) may be shaped as shown in FIG. 2 or FIG. 3. FIG.
 3 shows that the attachment block (24) further forms a barb portion (28)
 for enhancing its lock function.
 FIGS. 4 and 5 show two different embodiments of the latch (12). The lock
 (122) of the latch (12) in FIG. 5 is semicircular.
 FIG. 6 shows a latch (12) being locked in the attachment block (24),
 wherein the cross section of the tongue (120) is a rectangle.
 FIG. 7 shows another latch (12) being locked in the attachment block (24),
 wherein the cross section of the tongue (120) is round.
 FIGS. 6 to 8 show the attachment blocks (24) are respectively formed an
 inward hook end (240), the distance between the two hooks ends (240) is
 appreciably smaller than that of the tongue (122). The socket (20) as
 shown in FIG. 8 has a pair of attachment blocks (24) provided on opposite
 sides.
 As shown in FIG. 9, the latch (12) and the attachment block (24) are
 inverted. That is, the latch (12) is formed on the socket (20) and the
 attachment block (24) is formed on the bulb base (10) and a bulb is
 installed thereon as shown in FIG. 10.
 The present invention is obviously advantageous because of its easy
 assembly of the bulb with its socket and quick replacement of the bulbs.