Patent Publication Number: US-6039593-A

Title: Lamp base structure of a series of Christmas lamps

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a lamp base structure of a series of Christmas lamps, especially to a lamp base the outer conducting piece of which has a preferred water-proof effect. 
     2. Description of the Prior Art 
     In the prior lamp base structure of a series of Christmas lamps, metal conducting pieces (positive and negative) are engaged on the center of the seat and the peripheral wall of the lamp base. As the lamp is engaged on a predetermined position of the lamp base, those metal conducting pieces come into contact with predetermined positions of the lamp base, thus the weight of the lamp is reduced. 
     However, the outer conducting piece engaged on the inner peripheral wall of the lamp base has a plate shape. Therefore, as the conducting piece is engaged in the engaging hole of the peripheral wall of the lamp base, the gap between the conducting pieces and the outer periphery of the lamp base is smaller, approximately 1 mm. If the prior lamp base structure is used as a water-proof structure, it is probable that the water may enter into the lamp from the outer periphery of the lamp base, thus it will not conform with the security standard of U.S. UL 588. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention provides a lamp base structure of a series of Christmas lamps, wherein a through hole and an engaging hole are installed on the central portion and the near rim portion of the groove seat, respectively, while a central conducting piece and an outer conducting piece are installed on the through hole and the engaging hole. A engaging groove is formed on the inner peripheral wall of the lamp base corresponding to said engaging hole. A bent portion is formed between the upper end penetrating portion and the lower end portion of the outer conducting piece, and the penetrating portion is shifted toward the center of the lamp base groove. An engaging block is engaged in the gap of the engaging hole above the bent portion of the outer conducting piece. 
     By said lamp base structure, the width of said groove engaging hole corresponds to the length of the bent portion between the lower end portion and the upper end penetrating portion of the outer conducting piece. A protrusion is located on the upper end penetrating portion of the outer conducting piece. A gap is located between the protrusion and the lower end portion. This gap will cause the water outside the lamp base to drain less easily to the outer conducting piece, thus the present invention will attain a preferred water-proof effect. 
    
    
     The present invention will be better understood and its numerous objects and advantages will become apparent to those skilled in the art by referencing the following drawings: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is perspective view of the present invention. 
     FIG. 2 is a front cross sectional view of FIG. 1. 
     FIG. 3 is an elevational view of the lamp base in FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The details of the present invention may be referred to in FIGS. 1, 2 and 3. In the lamp base (A) of the present invention, a transversal groove (1) is formed on the upper end thereof, and a through hole (21) and an engaging hole (22) are installed on the central portion and the near rim portion of the groove seat (2), respectively. A central conducting piece (3) and an outer conducting piece (4) are installed on the through hole (21) and the engaging hole (22), respectfully, said central conducting piece (3) and outer conducting piece(4) may be contacted with the predetermined position on a lamp (not shown) screwed fixedly on the lamp base (A), thus the weight of the lamp is reduced. 
     Further, an engaging groove (A1) is formed on the inner peripheral wall of the lamp base (A) corresponding to said engaging hole (22). 
     Moreover, the lower end portion (40) of the outer conducting piece (4) is engaged on the engaging groove (A1) of the lamp base, and a bent portion (42) is located between the upper end penetrating portion (41) and the lower end portion (40) of the outer conducting piece (4). A protrusion (43) is located on the upper end penetrating portion (41) of the outer conducting piece (4). A gap (G) is located between the protrusion (43) and the near rim portion of the engaging hole (22). The upper end penetrating portion (41) is positioned toward the center of the lamp base groove (1). 
     The width of said groove engaging hole (22) corresponds to the length (1) of the bent portion (42) between the lower end portion (40) and the upper end penetrating portion (41) of the outer conducting piece (4). Therefore, the lower end portion (40) of the outer conducting piece (4) is engaged within the engaging groove (A1) of the lamp base, the bent portion (42) of the outer conducting piece (4) will enter into the engaging hole (22), while the upper end penetrating portion (41) will be projected upwards from the groove (1). 
     As the outer conducting piece (4) is engaged on the predetermined position of the lamp base engaging groove (A1), a gap (G) exists between the protrusion (43) and the portion of the engaging hole (22) located on the near rim portion of the groove seat. 
     An engaging block (5) is engaged in the gap (G) of the engaging hole (22) above the bent portion (42) of the outer conducting piece. Since the engaging block (5) is integrally combined with the groove seat (2), the engaging block (5) will substantially increase the gap between the outer rim of the groove (1) and the outer conducting piece (4), about 3 mm. This longer gap (comparing with that from the prior art) will cause the water outside the lamp base to drain less easily to the outer conducting piece, thus the present invention will attain a preferred water-proof effect. 
     Although the preferred embodiment of the present invention has been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.