BACKGROUND OF THE INVENTION
[0001] The present invention relates to a plug inner frame and, more particularly, to a
plug inner frame in which a fuse can be received.
[0002] Electric appliances or equipment utilized in daily lives or industries generally
utilize a plug for coupling with a socket for electrical connection. A typical plug
includes two blades and an optional grounding prong or blade. A fuse can be mounted
in the plug for safety consideration. The fuse melts when there is an excessive current
load, forming an open circuit for safety. The blades are fixed on an inner frame and
then placed in a mold so that a housing can be formed around the inner frame by injection
molding.
[0003] FIG. 1A shows a perspective view of a conventional plug inner frame 1. FIG. 1B shows
a perspective view of the plug inner frame 1 of FIG. 1A with wires attached to the
plug inner frame 1. FIG. 2 shows a bottom plan view of the plug inner frame 1 of FIG.
1A. FIG. 3 shows a top plan view of the plug inner frame 1 of FIG. 1A.
[0004] Plug inner frame 1 includes a frame body 11 having opposite first and second sides
10 and 13. First side 10 includes a fuse-receiving seat 12 having a recessed portion
121 for receiving a fuse and forming a raised portion 122 on second side 13, with
first and second lower areas 123A and 123B formed on second side 13 and located at
opposite sides of raised portion 122. First and second conductive plates 124 and 125
are mounted in recessed portion 421 and extend from first side 10 through second side
13. First and second blades 15 and 14 extend away from first side 10 of plug inner
frame 1 and located at a side of recessed portion 121. A grounding prong 16 extends
away from first side 10 of plug inner frame 1 and spaced from first and second blades
15 and 14 by recessed portion 121. A first wire-receiving seat 151 is formed in first
lower area 123A and electrically connected to first blade 15. A second wire-receiving
seat 141 is formed on raised portion 122 and electrically connected to first conductive
plate 124. Second conductive plate 125 is electrically connected to second blade 14.
Thus, second wire-receiving seat 141 is electrically connected to second blade 14
when a fuse is received in recessed portion 121 and in electrical connection with
first and second conductive plates 124, 125. A third wire-receiving seat 161 is formed
on second lower area 123B and electrically connected to grounding prong 16. Each wire
receiving seat 151, 141, 161 receives an end of a wire 171 having an insulating plastic
sheath 17. However, the thickness of second wire-receiving seat 141 and the thickness
of raised portion 122 result in a bulky structure needing more material. The final
plug product is heavy and not aesthetically pleasant.
[0005] FIG. 4 shows a perspective view of another conventional plug inner frame 2.
The plug inner frame 2 includes a frame body 21 that has a raised portion 222. A first
wire-receiving seat 251 is formed on a lower area at a side of raised portion 222
and includes an opening 252 facing away from frame body 21. A second wire-receiving
seat 241 is formed on the raised portion 222 and has a U-shaped opening 243 for clamping
an end of a cable, providing a lower profile of the resultant plug product. However,
opening 243 of second wire-receiving seat 24 and opening 252 of first wire-receiving
seat 25 have different orientations and, thus, require two separate wire-coupling
processes.
[0006] FIG. 5 shows an exploded, perspective view of a further conventional plug inner frame
3 with a cap 36. An example of such a conventional plug inner frame is disclosed in
GB 2370163. Plug inner frame 3 includes a frame body 37 having a raised portion 30 on a side
and a recessed portion on the other side. A conductive plate is received in the recessed
portion and has a flat extension 31 connected to a wire-receiving seat 32 in a lower
area 33. Two wire-receiving seats 34 and 35 are placed on opposite sides of wire-receiving
seats 32. Wire-receiving seat 35 is electrically connected to a grounding prong (not
labeled). A cap 36 is coupled to frame body 37 and includes partitioning walls 361
for isolating wires coupled to wire-receiving seats 34, 32, 35. However, wire-receiving
seats 34, 32, 35 having U-shaped cross sections must be rolled by a tool to clamp
wires in place, which is difficult to carry out in a small space where wire-receiving
seats 34, 32, 35 are placed side by side and have small spacing therebetween. Furthermore,
the tool that rolls wire-receiving seats 34, 32, 35 at the same time is liable to
break. Further, the isolating function is lost if no cap 36 is provided.
BRIEF SUMMARY OF THE INVENTION
[0007] A plug inner frame according to the preferred teachings of the present invention
includes a frame body having opposite first and second sides. The first side includes
a fuse-receiving seat having a recessed portion for receiving a fuse and forming a
raised portion on the second side. A first lower area is formed on the second side
and located at a side of the raised portion. First and second conductive plates are
mounted in the recessed portion and extend from the first side through the second
side. First and second blades are mounted to the frame body and extend away from the
first side. The second blade is electrically connected to the second conductive plate.
A first wire-receiving seat is formed in the first lower area and electrically connected
to the first blade. A second wire-receiving seat is formed in the first lower area
and spaced from the first wire-receiving seat. The second wire-receiving seat is electrically
connected to the first conductive plate. The second wire-receiving seat is electrically
connected to the second blade when the fuse is received in the recessed portion and
in electrical connection with the first and second conductive plates. The second wire-receiving
seat is intermediate the first-wire receiving seat and the second blade. Each of the
first and second wire-receiving seats includes an opening facing away from the frame
body.
[0008] In a most preferred form, the frame body includes a protrusion extending from an
edge of the second side. The first lower area includes two spaced ribs adjacent to
the protrusion. The first conductive plate includes an extension extending from the
raised portion to the second wire-receiving seat. The extension is received and positioned
in a path defined by the ribs and has a distal end fixed in a groove in the protrusion.
Furthermore, the raised portion includes a projection, and the first conductive plate
includes a section mounted on the raised portion and having a through-hole through
which the projection extends, positioning the first conductive plate in place. The
second side further includes a second lower area spaced from the first lower area
by the raised portion. A grounding prong extends away from the first side. A third
wire-receiving seat is formed on the second lower area and electrically connected
to the grounding prong.
[0009] In a most preferred form, the raised portion includes a coupling groove. A cap is
coupled to the second side and includes an engaging plate coupled with the coupling
groove. The cap further includes an end having spaced first, second, third, and fourth
partitioning plates, defining first, second, and third compartments therebetween.
The first partitioning plate includes a first arcuate edge at an outer side thereof.
The first and second partitioning plates are interconnected by a first interconnecting
wall therebetween. The first interconnecting wall has a second arcuate edge. The third
and fourth partitioning plates are interconnected by a second interconnecting wall
therebetween. The second interconnecting wall has a third arcuate edge. The fourth
partitioning wall includes a fourth arcuate edge at an outer side thereof. The third
partitioning plate has L-shaped cross section and defines a corner receiving the second
wire-receiving seat. The cap can further include a tail piece abutting distal ends
of the first, second, third, and fourth partitioning plates.
[0010] In a most preferred form, the frame body further includes a carrier plate extending
therefrom. Spaced first, second, third, and fourth partitioning walls extend perpendicularly
from the carrier plate. A first spacing is formed between the first and second partitioning
walls for receiving a first cable coupled to the first wire-receiving seat. A second
spacing is formed between the second and third partitioning walls for receiving a
second cable coupled to the second wire-receiving seat. A third spacing is formed
between the third and fourth partitioning walls for receiving a third cable coupled
to the third wire-receiving seat. The second and third partitioning walls have a protrusion
formed therebetween. A groove is formed in the protrusion. The first conductive plate
includes an extension having a distal end fixed in the groove.
[0011] The present invention will become clearer in light of the following detailed description
of illustrative embodiments of this invention described in connection with the drawings.
DESCRIPTION OF THE DRAWINGS
[0012] The illustrative embodiments may best be described by reference to the accompanying
drawings where:
FIG. 1A shows a perspective view of a conventional plug inner frame.
FIG. 1B shows a perspective view of the plug inner frame of FIG. 1A with wires attached
to the plug inner frame.
FIG. 2 shows a bottom plan view of the plug inner frame of FIG. 1A.
FIG. 3 shows a top plan view of the plug inner frame of FIG. 1A.
FIG. 4 shows a perspective view of another conventional plug inner frame.
FIG. 5 shows an exploded, perspective view of another conventional plug inner frame
with a cap.
FIG. 6 shows a perspective view of a plug inner frame of an embodiment according to
the preferred teachings of the present invention.
FIG. 7 shows a bottom plan view of the plug inner frame of FIG. 6.
FIG. 8 shows a top plan view of the plug inner frame of FIG. 6.
FIG. 9 shows an exploded, perspective view of the plug inner frame of FIG. 6 and a
cap mounted to the plug inner frame.
FIG. 10 shows a perspective view of the plug inner frame and the cap of FIG. 9.
FIG. 11 shows a cross-sectional view of the plug inner frame of FIG. 6.
FIG. 12 shows a perspective view of a plug inner frame of another embodiment according
to the preferred teachings of the present invention with wires attached to the plug
inner frame.
FIG. 13 shows a final product of a plug formed by the plug inner frame according to
the preferred teachings of the present invention.
FIG. 14 shows an exploded perspective view of the plug inner frame of FIG. 12 and
a cap mounted to the plug inner frame.
FIG. 15A shows a perspective view of the plug inner frame and the cap of FIG. 14.
FIG. 15B shows a cross-sectional view of the plug inner frame and the cap of FIG.
15A.
FIG. 16 shows a cross-sectional view of the plug inner frame of FIG. 14.
All figures are drawn for ease of explanation of the basic teachings of the present
invention only; the extensions of the Figures with respect to number, position, relationship,
and dimensions of the parts to form the preferred embodiment will be explained or
will be within the skill of the art after the following teachings of the present invention
have been read and understood. Further, the exact dimensions and dimensional proportions
to conform to specific force, weight, strength, and similar requirements will likewise
be within the skill of the art after the following teachings of the present invention
have been read and understood.
DETAILED DESCRIPTION OF THE INVENTION
[0013] A plug inner frame according to the preferred teachings of the present invention
is shown in FIGS. 6-11 of the drawings and generally designated 4. According to the
preferred form shown, plug inner frame 4 includes a frame body 41 having opposite
first and second sides 40 and 43. First side 40 includes a fuse-receiving seat 42
having a recessed portion 421 for receiving a fuse and forming a raised portion 422
on second side 43, with first and second lower areas 423A and 423B formed on second
side 43 and located at opposite sides of raised portion 422. Raised portion 422 includes
a projection 427 on an end thereof. Furthermore, raised portion 422 includes a coupling
groove 426. Frame body 41 further includes a protrusion 412 extending from an edge
of second side 43 and having a groove 413 formed therein. First lower area 423A includes
two spaced ribs 431 adjacent to projection 427. A path is defined between ribs 431.
[0014] According to the preferred form shown, first and second conductive plates 424 and
425 are mounted to frame body 41. First conductive plate 424 includes two arms 424D
(FIG. 7) in recessed portion 421 and extending from first side 40 through second side
43. First conductive plate 424 further includes an interconnecting section 424A interconnected
between arms 424D and located on raised portion 422. Interconnecting section 424A
has a through-hole through which projection 427 extends to position first conductive
plate 424 in place. First conductive plate 424 further includes an extension 424B
extending from interconnecting section 424A and received and positioned in the path
between ribs 431. Extension 424B has a distal end 424C fixed in groove 413 (FIG. 7).
Thus, first conductive plate 424 is prevented from shifting away its position due
to pressure or vibration during subsequent wire-coupling procedures and a subsequent
injection molding procedure. Second conductive plate 425 includes two arms 425C (FIG.
7) in recessed portion 421 and extending from first side 40 through second side 43.
Second conductive plate 425 further includes an interconnecting section 425A interconnected
between arms 425C and located on raised portion 422 and spaced from interconnecting
section 424A. Second conductive plate 425 further includes an extension 425B extending
from interconnecting section 425A.
[0015] Spaced first and second blades 45 and 44 extend away from first side 40 and located
at a side of recessed portion 421. Second blade 44 is electrically connected to extension
425B of second conductive plate 425. A grounding prong 46 extends away from first
side 40 and spaced from first and second blades 45 and 45 by recessed portion 421.
A first wire-receiving seat 451 is formed in first lower area 423A and electrically
connected to first blade 45. A second wire-receiving seat 441 is formed in first lower
area 423A and electrically connected to extension 424B. Second wire-receiving seat
441 is electrically connected to second blade 44 when a fuse is received in recessed
portion 421 and electrically connected to arms 424D and 425C of first and second conductive
plates 424, 425. Second wire-receiving seat 441 is intermediate first wire-receiving
seat 451 and second blade 44. Each of first and second wire-receiving seats 451, 441
includes a receptacle having an opening 452, 442 facing away from frame body 41. The
receptacles extend toward frame body 41. A third wire-receiving seat 161 is formed
in second lower area 123B and electrically connected to grounding prong 16. Each wire
receiving seat 151, 141, 161 receives an end of a wire 471A, 471B, 471C (FIG. 12)
having an insulating plastic sheath 17.
[0016] According to the preferred form shown, a cap 48 is coupled to second side 43 of frame
body 41. Cap 48 includes an engaging plate 481 (FIG. 9) for coupling with coupling
groove 426 of raised portion 422. This prevents molten plastic material for forming
the housing of the plug flows along a gap 411 (see FIG. 12) between a periphery of
first conductive plate 424 and raised portion 422 into recessed portion 421 at first
side 40. Thus, plastic material would not form a structure in recessed portion 421
hindering insertion of the fuse.
[0017] Cap 48 further includes spaced first, second, third, and fourth partitioning plates
483A, 483B, 483C, and 483D on an end thereof, defining first, second, and third compartments
483E, 483F, and 483G therebetween for receiving and isolating wires 471A, 471B, 471C.
First partitioning plate 483A includes an arcuate edge 483H at an outer side thereof.
First and second partitioning plates 483A and 483B are interconnected by a first interconnecting
wall therebetween. The first interconnecting wall has an arcuate edge 483J. Third
and fourth partitioning plates 483C and 483D are interconnected by a second interconnecting
wall therebetween. Second interconnecting wall has an arcuate edge 484L. Fourth partitioning
plate 483D includes an arcuate edge 483I at an outer side thereof. Third partitioning
plate 483C has L-shaped cross sections and defines a corner receiving second wire-receiving
seat 441 to prevent second wire-receiving seat 441 from falling during injection molding.
Short circuit or poor contact resulting from falling of second wire-receiving seat
441 during injection molding is, thus, avoided. Arcuate edges 483H, 483I, 483J, 483L
guide and allow easy mounting of wires 471A, 471B, 471C. This avoids wires 471A, 471B,
471C from being pinched and allows easy assembly.
[0018] FIGS. 12, 14, 15A, 15B, and 16 show a modification of the plug inner frame 4 according
to the preferred teachings of the present invention, wherein like reference numerals
designate like elements. In this embodiment, the frame body 41 does not have protrusion
412. However, frame body 41 includes a carrier plate 49 extending from an edge of
first lower area 423A. Spaced first, second, third, and fourth partitioning walls
490, 491, 492, and 493 extend perpendicularly from the carrier plate 49. A first spacing
is formed between first and second partitioning walls 490 and 491 for receiving and
guiding a wire 471A coupled to first wire-receiving seat 451. A second spacing is
formed between second and third partitioning walls 491 and 492 for receiving and guiding
a wire 47 1 B coupled to second wire-receiving seat 441. A third spacing is formed
between third and fourth partitioning walls 492 and 493 for receiving and guiding
a wire 471C coupled to third wire-receiving seat 461. Thus, short circuit resulting
from contact between wires 471A, 471B, 471C is prevented. Furthermore, second and
third partitioning walls 491 and 492 have a protrusion 494 formed therebetween. A
groove 495 is formed in protrusion 494 and securely receives distal end 424C of extension
424B. Undesired displacement of first conductive plate 424 resulting from pressure
or vibration during subsequent injection molding is, thus, avoided. Note that the
path between ribs 431 also position first conductive plate 424 to prevent undesired
displacement of first conductive plate 424 during subsequent injection molding.
[0019] According to the preferred form shown, cap 48 is also modified to include a tail
piece 482 (FIG. 14) extending outward from a body thereof. Tail piece 482 abuts distal
ends of first, second, third, and fourth partitioning walls 490, 491, 492, 493 to
prevent disengagement of wires 471A, 471B, 471C. Note that first, second, third, and
fourth partitioning plates 483A, 483B, 483C, 483D extending inward from tail piece
482 across a portion of a body of cap 48.
[0020] It can be appreciated that isolation of wires 471A, 471B, 471C can be achieved without
cap 48 to save manufacturing costs when partitioning walls 490, 491, 492, 493 are
utilized. It can be further appreciated that both openings 452 and 442 of first and
second wire-receiving seats 451 and 441 face away from frame body 41 in the same direction
and spaced from each other to allow easy wire-coupling processing without the risk
of breakage of the tool for carrying out the wire-coupling processing while allowing
smooth and quality-stable wire-coupling processing, for first and second wire-receiving
seats 451 and 441 are well supported by frame body 41.
[0021] Plug inner frame 4 according to the preferred teachings of the present invention
can be placed in a mold, and a final plug product 6 (FIG. 13) can be obtained after
injection molding.
[0022] Thus since the invention disclosed herein may be embodied in other specific forms
without departing from the spirit or general characteristics thereof, some of which
forms have been indicated, the embodiments described herein are to be considered in
all respects illustrative and not restrictive. The scope of the invention is to be
indicated by the appended claims, rather than by the foregoing description, and all
changes which come within the meaning and range of equivalency of the claims are intended
to be embraced therein.
1. A plug inner frame comprising, in combination:
a frame body (41) including opposite first and second sides (40, 43), with the first
side (40) including a fuse-receiving seat (42) having a recessed portion (421) for
receiving a fuse and forming a raised portion (422) on the second side (43), with
a first lower area (423A) being formed on the second side (43) and located at a side
of the raised portion (422);
first and second conductive plates (424, 425) mounted in the recessed portion (421)
and extending from the first side (40) through the second side (43); and
first and second blades (45, 44) mounted to the frame body (41) and extending away
from the first side (40), with the second blade (44) being electrically connected
to the second conductive plate (425), with a first wire-receiving seat (451) being
formed in the first lower area (423A) and electrically connected to the first blade
(45), with a second wire-receiving seat (441) being formed in the first lower area
(423A) and spaced from the first wire-receiving seat (451), with the second wire-receiving
seat (441) being electrically connected to the first conductive plate (424), with
the second wire-receiving seat (441) being electrically connected to the second blade
(44) when the fuse is received in the recessed portion (421) and in electrical connection
with the first and second conductive plates (424, 425), with the second wire-receiving
seat (441) being intermediate the first-wire receiving seat (451) and the second blade
(44), with each of the first and second wire-receiving seats (451, 441) including
an opening (452, 442) facing away from the frame body (41).
2. The plug inner frame as claimed in claim 1, with the frame body (41) including a protrusion
(412) extending from an edge of the second side (43), with a groove (413) being formed
in the protrusion (412), with the first conductive plate (424) including an extension
(424B) extending from the raised portion (422) toward the protrusion (412), with the
extension (424B) being in electrical connection with the second wire-receiving seat
(441) and having a distal end (424C) fixed in the groove (413).
3. The plug inner frame as claimed in claim 1, with the raised portion (422) including
a projection (427), and with the first conductive plate (424) including a section
(424A) mounted on the raised portion (422) and having a through-hole through which
the projection (427) extends, positioning the first conductive plate (424) in place.
4. The plug inner frame as claimed in claim 1, with the first conductive plate (424)
including an extension (424B) extending from the raised portion (422) to the second
wire-receiving seat (441), with the first lower area (423A) further including two
spaced ribs (431) defining a path, and with the extension (424B) being received and
positioned in the path.
5. The plug inner frame as claimed in claim 1, with the raised portion (422) including
a coupling groove (426), with the plug inner frame (4) further comprising, in combination:
a cap (48) coupled to the second side (43), with the cap (48) including an engaging
plate (481) coupled with the coupling groove (426).
6. The plug inner frame as claimed in claim 5, with the cap (48) further including an
end having spaced first, second, third, and fourth partitioning plates (483A, 483B,
483C, 483D), defining first, second, and third compartments (483E, 483F, 483G) therebetween,
with the first partitioning plate (483A) including a first arcuate edge (483I) at
an outer side thereof, with the first and second partitioning plates (483A, 483B)
being interconnected by a first interconnecting wall therebetween, with the first
interconnecting wall having a second arcuate edge (483J), with the third and fourth
partitioning plates (483C, 483D) being interconnected by a second interconnecting
wall therebetween, with the second interconnecting wall having a third arcuate edge
(484L), and with the fourth partitioning wall (483D) including a fourth arcuate edge
(483I) at an outer side thereof.
7. The plug inner frame as claimed in claim 1, with the second side (43) further including
a second lower area (423B) spaced from the first lower area (423A) by the raised portion
(422), with a grounding prong (46) extending away from the first side (40), with a
third wire-receiving seat (461) being formed on the second lower area (423B) and electrically
connected to the grounding prong (46), with the frame body (41) further including
a carrier plate (49) extending therefrom, with spaced first, second, third, and fourth
partitioning walls (490, 491, 492, 493) extending perpendicularly from the carrier
plate (49), with a first spacing being formed between the first and second partitioning
walls (490, 491) for receiving a first cable (471A) coupled to the first wire-receiving
seat (451), with a second spacing being formed between the second and third partitioning
walls (491, 492) for receiving a second cable (471B) coupled to the second wire-receiving
seat (441), and with a third spacing being formed between the third and fourth partitioning
walls (492, 493) for receiving a third cable (471C) coupled to the third wire-receiving
seat (461).
8. The plug inner frame as claimed in claim 7, further comprising, in combination: a
cap (48) coupled to the second side (43), with the cap (48) including a tail piece
(482) extending outward from a body thereof and abutting distal ends of the first,
second, third, and fourth partitioning walls (490, 491, 492, 493).
9. The plug inner frame as claimed in claim 8, with the cap (48) further including spaced
first and second partitioning plates (483A, 483B) extending inward from the tail piece
(482) across a portion of the body of the cap (48).
10. The plug inner frame as claimed in claim 9, with the cap (48) further including a
third partitioning plate (483C) spaced from the first and second partitioning plates
(483A, 483B) and extending inward from the tail piece (482) across a portion of the
body of the cap (48).
11. The plug inner frame as claimed in claim 10, with the third partitioning plate (483C)
having substantially L-shaped cross sections and defining a corner receiving the second
wire-receiving seat (441).
12. The plug inner frame as claimed in claim 7, with the second and third partitioning
walls (491, 492) having a protrusion (494) formed therebetween, with a groove (495)
being formed in the protrusion (494), and with the first conductive plate (424) including
an extension (424B) having a distal end (424C) fixed in the groove (495).
13. The plug inner frame as substantially hereinbefore described with reference to and
as shown in Figures 6-16 of the accompanying drawings.