Lamp socket assembly

A lamp socket assembly comprises: (1) a socket shell with the top end being closed by a top wall with a central opening; (2) a socket cap fastened to the socket shell for holding down an electrical wire; (3) a first metal contact positioned between the socket cap and the top wall of the socket shell, the first metal contact for making electrical contact with the tip contact of a lamp bulb and with one conductor of the electrical wire; and (4) a second metal contact for making electrical contact with the ring contact of a lamp bulb and with at another conductor of the electrical wire. The first metal contact comprises an arched portion, which is received by and protrudes through the central opening in the top wall of the socket shell to make electrical contact with the tip contact of a lamp bulb. The first metal contact further comprises: (1) a triangular portion for piercing the insulator of the electrical wire to make electrical contact with one of the conductors of the electrical wire; and (2) a rectangular mounting portion, which is received by a cavity in the socket shell, thereby firmly retaining the first metal contact with respect to the socket shell. The first metal contact may be stamped from a sheet of metal.

BACKGROUND OF THE INVENTION 
The present invention relates to a lamp socket assembly, and more 
particularly to the arrangement of the metal contact in a lamp socket 
assembly. 
A prior art lamp socket assembly with which this invention concerned is 
shown in FIG. 6 and includes a socket shell 2; a socket cap 3 fastened to 
the socket shell for holding down an electrical wire; a first metal 
contact A making electrical contact with the tip contact of a lamp bulb 4 
and with one conductor of the electrical wire; and a second metal contact 
24 making electrical contact with the ring contact of the lamp bulb 4 and 
with the other conductor of the electrical wire. The first metal contact A 
has a vertical front end A1, which is inserted through a hole 26 in the 
top wall of the socket shell 2 and which pierces the insulating covering 
of the electrical wire to make electrical contact with one conductor of 
the electrical wire. The first metal contact A also has a horizontal rear 
end disposed inside the socket shell below an inside projecting portion 25 
on the top wall of the socket shell 2. When the base of the lamp bulb 4 is 
threaded into the socket shell 2, the tip contact and the ring contact of 
the lamp bulb make electrical contact with, respectively, the first metal 
contact A and the second metal contact 24. Normally, the horizontal rear 
end of the first metal contact A is spaced from the projecting portion 25 
on the top wall of the socket shell 2; and, therefore, it makes electrical 
contact with the tip contact of the lamp bulb 4 when the lamp bulb is 
threaded into the socket shell 2. 
Still referring to FIG. 6, when the lamp bulb 4 is threaded into the socket 
shell 2, the tip contact of the lamp bulb is spaced from the projecting 
portion 25 on the top wall of the socket shell 2 at a distance longer than 
the thickness of the horizontal rear end of the first metal contact A. 
However, the first metal contact A tends to undergo elastic fatigue after 
long use. Therefore, a poor electrical contact or no electrical contact 
may occur when the horizontal rear end of the first metal contact A is 
disposed constantly in contact with the projecting portion 25 of the top 
wall of the socket shell 2. 
SUMMARY OF THE INVENTION 
The present invention is a lamp socket assembly with a first metal contact 
and a socket shell that work together to eliminate or reduce the problem 
described above. According to the preferred embodiment of the present 
invention, the first metal contact comprises an arched portion which 
projects into a central opening in the top wall of the socket shell to 
make electrical contact with the tip contact of the lamp bulb fastened to 
the socket shell. A triangular portion of the first metal contact pierces 
into the insulator on the electrical wire to make an electrical contact 
with the insulated conductor. A rectangular mounting portion of the first 
metal contact is firmly held in a cavity in the socket shell to stabilize 
the first metal contact.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1 and 2, a lamp socket assembly in accordance with the 
preferred embodiment of the present invention is generally comprised of a 
socket shell 2 with a top end and a bottom end, the bottom end being open 
for receiving the base of a lamp bulb, the top end being closed by a top 
wall with a central opening 22; a socket cap 3 for holding down an 
electrical wire 5, the socket cap 3 being fastened to the socket shell 2 
and covering the top end of the socket shell; a first metal contact 1 for 
making electrical contact with the tip contact of the lamp bulb and with 
one conductor of the electrical wire 5; and a second metal contact 24 for 
making electrical contact with the ring contact of the lamp bulb and with 
another conductor of the electrical wire 5. A lamp bulb 4 is inserted into 
the bottom end of the socket shell 2 and is screwed to the socket shell. 
The socket shell 2 has a transverse groove 21 through its top end for 
receiving the electrical wire 5. The socket cap 3 has two symmetrical 
hooks 31, which engage with respective retaining notches (not shown) in 
the transverse groove 21 of the socket shell 2 to hold the socket cap 3 in 
place and causing the first and second metal contacts 1, 24 to pierce the 
insulating covering on the electrical wire 5 and make respective contacts 
with the conductors in the electrical wire 5. 
Referring to FIGS. 3, 4, and 5, the first metal contact 1 is made from a 
flat metal plate B by stamping. As shown in FIG. 5, the first metal 
contact 1 comprises: (1) an arched portion 13 for protruding through the 
central opening 22 of the top wall of the socket shell 2 and for making 
electrical contact with the tip contact of a lamp bulb 4, as shown in 
FIGS. 1 and 2; (2) a triangular portion 11 for piercing the insulator of 
the electrical wire to make electrical contact with one of the conductors 
of the electrical wire; and (3) a rectangular mounting portion 12 which is 
received by cavity 23 in the socket shell 2, thereby firmly retaining the 
first metal contact 1 with respect to the socket shell 2, as shown in 
FIGS. 1 and 2. The triangular portion 11 is disposed in one direction and 
the arched portion 13 and the rectangular mounting portion 12 are disposed 
in the opposite direction. 
Referring again to FIGS. 1 and 2, when the rectangular mounting portion 12 
of the first metal contact 1 is inserted into cavity 23 in the socket 
shell 2, the arched portion 13 is received by and protrudes through the 
central opening 22 in the top wall of the socket shell 2. When the socket 
cap 3 is fastened to the socket shell 2, holding the electrical wire 5 in 
place, the triangular portion 11 of the first metal contact 1 pierces the 
insulating covering of the electrical wire 5 to make electrical contact 
with one conductor of the electrical wire 5; and the sharp tip of the 
second metal contact 24 pierces the insulating covering of the electrical 
wire 5 to make electrical contact with at another conductor of the 
electrical wire 5. When the lamp bulb 4 is fastened to the socket shell 2 
by a screw joint, the tip contact of the lamp bulb 4 makes electrical 
contact with the arched portion 13 of the first metal contact 1; and the 
ring contact of the lamp bulb 4 makes electrical contact with the second 
metal contact 24.