Electrical plug

An improved electrical plug includes a plug body of insulating material with front and rear end faces, a plurality of conducting prongs fixedly disposed in the plug body with the front portions projecting through the front end face of the plug body, a plurality of blind channels formed within the plug body through the rear end face adjacently parallel to the conducting prongs for receiving the insulated conductors therein, and a plurality of manually driving knobs coupled with the plug body in conjunction with the conducting prongs. Each of the driving knobs has a screw member secured to the inner side thereof, and a rectangular serrated member movably attached to the end of the screw member with the pointed teeth facing the blind channel, so that, by turning the driving knobs, the teeth perforate the insulation of the conductors without twisting the conductors, and firm electrical connections can be easily and quickly made without requiring any tools and skill.

BACKGROUND OF THE INVENTION 
This invention relates to an electrical plug which includes an electrical 
connector for connecting conducting prongs and entering insulated 
conductors without stripping off the insulating layer. 
In common practice, to connect a wire to a conventional plug as shown in 
FIG. 1a, it is necessary to disassemble the plug and strip off the 
insulating layer of a conductor to expose some extent of the conductor so 
that it can be made contact with the conducting prongs of the plug. For 
simplifying the connecting work this inventor offered an improved form of 
plug, as shown in FIG. 1b, that is disclosed in a U.S. Application Ser. 
No. 151,199. This form of plug is provided with conducting prongs having 
teeth at the ends thereof to be driven into the conductors which enter the 
plug body so that the insulating layer of the conductors are perforated 
and the inner conductors thereof respectively come into contact with the 
teeth. The driving force is given to a screw, by which the insulated 
conductor is pushed against the teeth, by using tools, such as, screw 
drivers. Although the requirement of stripping the insulated layer is 
neglected in that case, inconvenience still exists due to the need of 
tools. 
SUMMARY OF THE INVENTION 
An improved electrical plug having a plug body with front and rear end 
faces, and a plurality of conducting prongs fixedly disposed in the plug 
body with their front portions respectively projecting through the front 
end face, wherein the improvement comprises; a plurality of blind channels 
formed within the plug body through the rear end face adjacently parallel 
to the conducting prongs for facilitating the insertion of insulated 
conductors; and a plurality of electrical connecting means threadedly 
coupled with the plug body in conjunction with the rear portions of the 
conducting prongs and the front portions of said blind channels for 
respectively making electrical connections between the conducting prongs 
and the insulated conductors received in the blind channels; so that 
electrical connections can be easily and quickly done without requiring 
any tools and skill. 
Advantageously, each of the electrical connecting means may include a 
driving knob suitable for hand operations, a conductive screw member fixed 
to the driving knob and extending at right angle toward the blind channel 
in the plug body through a threaded opening formed in the rear portion of 
the conducting prong thereof; and a rectangular serrated member movably 
attached to the end of the conductive screw with the pointed teeth facing 
the blind channel for penetrating into the insulated layer of the 
conductor received within the blind channel; so that, by manually turning 
the driving knob, electrical connections between the prongs and the 
insulated conductors therein can be easily and quickly made without 
stripping off the insulating layer of the conductors. 
An object of the invention is to provide an electrical plug which has an 
electrical connector provided with pointed teeth at the end thereof and 
non-conductive knob provided for driving the teeth by hand to come into 
contact with an inner conductor of the wire by penetrating through the 
insulating layer thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
As shown in FIGS. 2, 3 and 4, an electrical plug according to the invention 
includes a plug body 10 made of an electrically insulating material and 
having two halves of molded sections coupled to substantially form a shape 
which has a front end face 1 and rear end face 2 interconnected by side 
faces 3. At the front end face 2 a pair of conducting prongs 20 are 
forwardly projecting for insertion into a socket. The rear portions of the 
prongs 20 are respectively received in grooves 14 in the plug body 10 and 
each of them has a circular threaded opening 21 near each rear end 
thereof. For receiving the entering insulated conductors 15 a pair of 
blind channels 13 are bored at the rear end face 2 with some extent of its 
front portion extended in a parallelly adjacent position relative to the 
respective rear portion of the prongs 20. 
At each side face 3 of the plug body 10 is provided with a recess 11 
adapted to receive a circular knob 30 which forms a part of the electrical 
connector according to the invention. A slot 12 is bored at the center of 
the end face of each recess 11 and crisscrosses the groove 14. The ends of 
the slots 12 are extended until they communicate respective blind channels 
13. The knobs 30 are rotatably mounted in the respective recesses 11 and 
fixedly connected to respective conductive screws 32, i.e. the shank 
portions of the electrical connector in this invention, which are 
threadedly movable in the slots 12 and threadedly passing through the 
openings 21 upon operating the knobs 30. At each end of the screws 32 is a 
serrated member, having axially pointed teeth 33 which are projected 
laterally from the raised edges of a rectangular piece 35, movably 
attached to the screw 32 by means of an attached screw 34 so that the 
serrated member only axially moves when the screw 32 threadedly moves. 
These teeth 33 can be moved in direction at right angle to the respective 
entering insulated conductors 15 upon the threaded movement of the screws 
32. 
It can be noted that the connecting work in this plug can be easily done by 
inserting insulated conductors into the blind channels 13 and drivingly 
turning the knobs 30. As the knobs 30 are operated the respective teeth 33 
are driven to penetrate through of the insulating layers of the respective 
conductors 15 and come into contact with the respective conductors, 
thereby making electrical connections between the entering conductors 15 
and the conducting prongs 20 which are kept in contact with the conductive 
screws 32. 
It can be further noted that the plug described with reference to FIG. 4 is 
suitable for wires, i.e. insulated conductors, having larger cross section 
to obtain good electrical contacts and firm attachment to the plug. 
For wires of smaller cross section, to get good electrical contact and firm 
attachment to the plug, it is advantageous to construct the plug as shown 
in FIG. 5 in which the slot for receiving the conductors 43 are made to be 
elliptical. The conductor 43 is inserted into the slot with some extent of 
its end portion bent back and extending rearward after it reaches the end 
of the slot. Therefore the area of the conductor that can be in contact 
with the serrated member 44 will become larger. 
With the invention thus explained, it is apparent that obvious 
modifications and variations can be made without departing from the scope 
of the invention. It is therefore intended that the invention be limited 
only as indicated in the appended claims.