Abstrict
Insulator for electric heater which can make a heater coil to expand/contract
uniformly, and permits an easy fitting of the heater coil thereto,
and washing and drying machine having heater assembly therewith,
the insulator including a body part (30) formed of an insulating
material, a fixing slot in the body part for fixing the body part
(30) to a holding member, a coil seating part at an end of the body
part for being inserted in the heater coil (40) for supporting the
heater coil (40), and a seating slot between the coil seating part
and the body part for inserting the heat coil (40).
Claims
What is claimed is:
1. An insulator for an electric heater, the insulator comprising:
a body made of electric insulating material; a fixing slot formed
at the body for fixing the body to a supporting member; and a coil
passing portion formed at the body, through which a heater coil
loosely passes and seats.
2. The insulator as claimed in claim 1, wherein the coil passing
portion is a penetrating hole having an inner diameter larger than
an outer diameter of the heater coil.
3. The insulator as claimed in claim 2, wherein the coil passing
portion has a length longer than a pitch of the heater coil.
4. The insulator as claimed in claim 3, wherein the coil passing
portion is two and a half times or three times as long as the pitch
of the heater coil.
5. The insulator as claimed in claim 1, wherein an edge of the
coil passing portion is rounded.
6. The insulator as claimed in claim 1, wherein the coil passing
portion is formed at both longitudinal ends of the body, respectively.
7. An insulator for an electric heater, the insulator comprising:
a body made of electric insulating material; a fixing slot formed
at the body for fixing the body to a supporting member; and a coil
passing portion formed at an end of the body and inserted into an
interior of the heater coil to support the heater coil.
8. The insulator as claimed in claim 7, wherein the coil seating
portion comprises a convolution supporting surface for contacting
with and supporting the heater coil, and the convolution supporting
surface has a curvature corresponding to that of the heater coil.
9. The insulator as claimed in claim 8, wherein the coil seating
portion is formed in a circular plate, and has a penetrating hole
at a center thereof.
10. The insulator as claimed in claim 8, wherein the convolution
supporting surface has a rounded corner.
11. The insulator as claimed in claim 7, wherein the coil seating
portion has a thickness thicker than a pitch of the heater coil
and thinner than a thickness of the body.
12. The insulator as claimed in claim 7, wherein a seating slot
is formed between the coil seating portion and body, on which the
heater coil is seated.
13. The insulator as claimed in claim 12, wherein the seating slot
has a curvature corresponding to a curvature of the heater coil.
14. The insulator as claimed in claim 12, wherein the seating slot
has a thickness thinner than a pitch of the heater coil.
15. The insulator as claimed in claim 7, wherein the coil seating
portion has an inclined surface, a thickness thereof being gradually
thinned toward an end of the coil seating portion to facilitate
mount of the heater coil.
16. The insulator as claimed in claim 7, wherein the coil seating
portion is formed at both longitudinal ends of the body, respectively.
17. A heater assembly of a combined laundry washing/drying machine,
the heater assembly comprising: a housing for providing an air passage
communicating with a tub accommodating laundry to be dried; a supporting
plate disposed in an interior of the housing; a heater coil supported
by the supporting plate for generating heat, the heater coil being
electrically isolated from the supporting plate; and an insulator
including a body made of electric insulating material, a fixing
slot formed at the body for fixing the body to the supporting plate,
and a coil passing portion formed at the body, through which a heater
coil loosely passes and seats.
18. The heater assembly as claimed in claim 17, wherein the coil
passing portion is a penetrating hole having an inner diameter larger
than an outer diameter of the heater coil.
19. The heater assembly as claimed in claim 18, wherein the coil
passing portion has a length longer than a pitch of the heater coil.
20. The heater assembly as claimed in claim 18, wherein an edge
of the coil passing portion is rounded.
21. The heater assembly as claimed in claim 17, wherein the supporting
plate divides an inner space of the housing into upper and lower
portions.
22. The heater assembly as claimed in claim 21, wherein the coil
passing portion is formed at both longitudinal ends of the body,
respectively.
23. A heater assembly of a combined laundry washing/drying machine,
the heater assembly comprising: a housing for providing an air passage
communicating with a tub accommodating laundry to be dried; a supporting
plate disposed in an interior of the housing; a heater coil supported
by the supporting plate for generating heat, the heater coil being
electrically isolated from the supporting plate; and an insulator
including a body made of electric insulating material, a fixing
slot formed at the body for fixing the body to a supporting member,
and a coil passing portion formed at an end of the body and inserted
into an interior of the heater coil to support the heater coil.
24. The heater assembly as claimed in claim 23, wherein the coil
seating portion comprises a convolution supporting surface for contacting
with and supporting the heater coil, and the convolution supporting
surface has a curvature corresponding to that of the heater coil.
25. The heater assembly as claimed in claim 24, wherein the coil
seating portion is formed in a circular plate, and has a penetrating
hole at a center thereof.
26. The heater assembly as claimed in claim 24, wherein the convolution
supporting surface has a rounded corner.
27. The heater assembly as claimed in claim 23, wherein the coil
seating portion has a thickness thicker than a pitch of the heater
coil and thinner than a thickness of the body.
28. The heater assembly as claimed in claim 23, wherein the insulator
further includes a seating slot formed between the coil seating
portion and body, on which the heater coil is seated.
29. The heater assembly as claimed in claim 28, wherein the seating
slot has a thickness thinner than a pitch of the heater coil.
30. The heater assembly as claimed in claim 23, wherein the coil
seating portion has an inclined surface, a thickness thereof being
gradually thinned toward an end of the coil seating portion to facilitate
mount of the heater coil.
31. The heater assembly as claimed in claim 23, wherein the supporting
plate divides an inner space of the housing into upper and lower
portions.
32. The heater assembly as claimed in claim 31, wherein the coil
passing portion is formed at both longitudinal ends of the body,
respectively.
Description TECHNICAL FIELD
[0001] The present invention relates to an electric heater, and
more particularly, to an insulator for supporting a heater coil
generating heat, and a heater assembly with the same for use in
a combined laundry washing/drying machine.
BACKGROUND ART
[0002] An electric heater is activated by an electric supply to
heat ambient air, and is used for various purposes. For example,
the electric heater is utilized for a laundry dryer or a washing
machine having washing and drying functions.
[0003] FIG. 1 is a cross sectional view of a conventional combined
laundry washing/drying machine, in which a drum-type washing machine
having a drying function is shown. The combined laundry washing/drying
machine includes a tub 2 supported by a damper 7 and a spring 6
in a body 1 for storing washing water, a washing drum 3 for washing,
rinsing and dehydrating the laundry, a motor 4 disposed under the
tub 2 for transmitting a rotary force to the washing drum 3, and
a pulley and belt 5 disposed between the motor 4 and a drum shaft
(not shown) for transmitting the rotary force of the motor 4 to
the drum shaft.
[0004] The tub 2 is provided at an outward proper position thereof
with a blast duct 8 communicated with the washing drum 3. A blast
fan 9 compulsorily circulates the air within the blast duct 8, and
a heater assembly 10 is disposed at the front of the blast fan 9
to heat the air supplied to the washing drum 3.
[0005] With the structure of the combined laundry washing/drying
machine as described above, after a series of washing, rinsing and
dehydrating processes are completed, the washing drum 3 is rotated
at a low speed to uniformly mix the laundry. At that time, a power
is supplied to the heater assembly 10 and the blast fan 9, so that
the heater assembly 10 generates heat, thereby heating the air.
The heated air is circulated within the washing drum 3 and the blast
duct 8 to dry the laundry.
[0006] FIGS. 2 to 4 show the structure of another conventional
heater assembly, in which the heater assembly is enclosed by a housing
11. The housing 11 includes a bottom plate 12, and side plates 13
and 14 vertically extended from both edges of the bottom plate 12.
Mounting taps 15 are formed on upper ends of the side plates 13
and 14, and the housing 11 is mounted to the blast duct 8 by the
mounting taps 15.
[0007] An interior space of the housing 11 is divided into upper
and lower halves by a metallic supporting plate 16. The supporting
plate 16 is fixed to the side plates 13 and 14, with protruding
arms 17 formed at both ends of the supporting plate inserted into
penetrating holes of the side plates.
[0008] The supporting plate 16 is provided with a heater coil 18
for generating heat by use of electric resistance produced by flowing
electric current through the coil. The heater coils 18 are disposed
in several rows on upper and lower portions of the supporting plate
16, with the respective heater coils elongated in left and right
directions of the supporting plate. The heater coils 18 are electrically
connected to each other, and terminals 19 are provided at both ends
of the heater coil 18 to supply the power to the heater coil.
[0009] The heater coil 18 is supported by an insulator 20 fixed
to the supporting plate 16. The insulator 20 is made of insulation
material to electrically isolate the heater coil 18 from the supporting
plate 16 and support the heater coil against the supporting plate
16. The insulator 20 generally penetrates the supporting plate 16,
and has an upper portion protruded upward from the supporting plate
16 and a lower portion protruded downward from the supporting plate,
with the portions of the insulator which are upward and downward
protruded from the supporting plate are symmetrical to each other.
[0010] FIG. 4 shows the structure of the insulator, in which the
heater coil 18 is supported by the insulator 20. The insulator 20
of heat insulating material is formed in a plate shape, with an
upper end of the insulator being symmetrical to a lower end thereof.
Therefore, it will be described on the construction of the upper
end only.
[0011] The insulator 20 has at both ends parallel notches 21 for
mounting the insulator to the supporting plate 16. Also, the insulator
20 has straight slots 22 upwardly and downwardly formed from a center
of the upper surface of the insulator. Each of the straight slots
22 has a length equal to the half of the length between the parallel
notches. The straight slot 22 is provided at a lower end with a
fixing notch 24 for fixing the heater coil 18.
[0012] The insulator 20 has at the upper surface thereof inclined
guide surfaces 23. The inclined guide surface 23 is to guide a process
of insulating the heater coil 18 into the insulator 20. The insulator
20 has lateral notches 25 each formed at both sides thereof. Each
of the lateral notches 25 has an inclined angle similar to the inclined
guide surface 23. The lateral notch 25 is flush with the fixing
notch 24.
[0013] It will now be described on the process of insulating the
heater coil 18 into the insulator 20 in brief. Adjacent first, second
and third convolutions 18a, 18b and 18c of the heater coil 18 are
inserted into the fixing notch 24 and two lateral notches 25 of
the insulator 20, respectively. Specifically, the first convolution
18a is disposed at a position corresponding to the straight slot
22, while the second and third convolutions 18b and 18c are disposed
at the guide surface 23 of the insulator 20, respectively.
[0014] Next, the heater coil 18 is pressed, such that the respective
convolutions 18a, 18b and 18c is moved in an arrow direction. The
respective convolutions 18a, 18b and 18c is guided along the straight
slot 22 and the guide surface 23, and is inserted and fixed to the
fixing notch 24 and the lateral notches 25.
[0015] The respective second and third convolutions 18b and 18c
is deformed in a direction away from the first convolution 18a along
the guide surface 23, and when it comes in contact with the lateral
notch 25, is restored into its original shape to catch the lateral
notch.
[0016] The conventional heater coil has some problems as follows.
[0017] First, the heater coil 18 generates a lot of heat during
operation, thereby increasing a temperature of the heater coil,
while the heater coil is maintained at a room temperature during
no operation. This means the repeated expansion and contraction
of the heater coil 18. However, the first, second and third convolutions
18a, 18b and 18c of the heater coil which are secured to the insulator
20 cannot expand and contract, contrary to other portions. The first,
second and third convolutions 18a, 18b and 18c, however, receive
more thermal stress than other portions of the heater coil receive,
so that this phenomenon exerts an advert influence on the heater
coil in the strength aspect. In addition, the heat is not uniformly
distributed over the total heater coil 18.
[0018] Secondly, it is significantly complicate to mount the heater
coil 18 to the insulator 20. Specifically, in order to insert the
heater coil into the insulator 20, the first, second and third convolutions
18a, 18b and 18c must be inserted into the fixing notch 24 and the
lateral notches 25 at the same time. At that time, the elastic direction
of the resilience second 18b is counter to that of the third convolution
18c, as shown in FIG. 4. Accordingly, an operator has to guide and
press the second and third convolutions 18b and 18c using his/her
fingers, with both ends of the first, second and third convolutions
18a, 18b and 18c to be inserted into the insulator 20 being griped
by both bands. Such an operation is very complicate, and if it is
not careful, the first, second and third convolutions 18a, 18b and
18c are deformed. At this case, the supporting state of the heater
coil 18 gets worse.
DISCLOSURE OF THE INVENTION
[0019] Accordingly, the present invention is directed to an insulator
for an electric heater that substantially obviates one or more of
the problems due to limitations and disadvantages of the related
art.
[0020] An object of the present invention is to provide an insulator
for an electric heater, by which a heater coil can evenly expand
and contract over the entire length thereof, and a heater assembly
with the same for use in a combined laundry washing/drying machine.
[0021] Another object of the present invention is to provide an
insulator for an electric heater capable of easily mounting a heater
coil, and a heater assembly with the same for use in a combined
laundry washing/drying machine.
[0022] A further object of the present invention is to provide
an insulator for an electric heater capable of preventing a heater
coil from being deformed during a mounting process, and a heater
assembly with the same for use in a combined laundry washing/drying
machine.
[0023] Additional features and advantages of the invention will
be set forth in the description which follows, and in part will
be apparent from the description, or may be learned by practice
of the invention. The objectives and other advantages of the invention
will be realized and attained by the structure particularly pointed
out in the written description and claims thereof as well as the
appended drawings.
[0024] To achieve these and other advantages and in accordance
with the purpose of the present invention, as embodied and broadly
described, there is provided an insulator for an electric heater,
the insulator comprising: a body made of electric insulating material;
a fixing slot formed at the body for fixing the body to a supporting
member; and a coil passing portion formed at the body, through which
a heater coil loosely passes and seats.
[0025] The coil passing portion is a penetrating hole having an
inner diameter larger than an outer diameter of the heater coil,
and the coil passing portion has a length longer than a pitch of
the heater coil. Preferably, the coil passing portion is two and
a half times or three times as long as the pitch of the heater coil.
[0026] An edge of the coil passing portion is rounded to prevent
the interference between the heater coil and the coil passing portion
during expansion and contraction of the heater coil.
[0027] According to another aspect of the present invention, there
is provided an insulator for an electric heater, the insulator comprising:
a body made of electric insulating material; a fixing slot formed
at the body for fixing the body to a supporting member; and a coil
passing portion formed at an end of the body and inserted into an
interior of the heater coil to support the heater coil.
[0028] The coil seating portion comprises a convolution supporting
surface for contacting with and supporting the heater coil, and
the convolution supporting surface has a curvature corresponding
to that of the heater coil. The convolution supporting surface has
a rounded corner so as to smoothly receive the heater coil.
[0029] The coil seating portion is formed in a circular plate,
and has a penetrating hole at a center thereof to save material.
[0030] The coil seating portion has a thickness thicker than a
pitch of the heater coil and thinner than a thickness of the body.
[0031] A seating slot is formed between the coil seating portion
and body, on which the heater coil is seated. To this end, the seating
slot has a curvature corresponding to a curvature of the heater
coil. The seating slot has a thickness thinner than a pitch of the
heater coil.
[0032] The coil seating portion has an inclined surface, a thickness
thereof being gradually thinned toward an end of the coil seating
portion to facilitate mount of the heater coil.
[0033] Accordingly, the heater coil may expand and contract without
the interference between the heater coil and the coil passing portion.
In addition, heater coil is mounted to the external portion of the
coil seating portion through only a insertion process. At that time,
it may minimize the deformation of the heater coil.
[0034] Furthermore, the present invention provides a combined laundry
washing/drying machine employing two types of above-mentioned insulators.
[0035] It is to be understood that both the foregoing general description
and the following detailed description are exemplary and explanatory
and are intended to provide further explanation of the invention
as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The accompanying drawings, which are included to provide
a further understanding of the invention and are incorporated in
and constitute a part of this specification, illustrate embodiments
of the invention and together with the description serve to explain
the principles of the invention.
[0037] In the drawings:
[0038] FIG. 1 is a cross sectional view of a conventional combined
laundry washing/drying machine;
[0039] FIG. 2 is a plan view of a conventional heater assembly;
[0040] FIG. 3 is a front view of the heater assembly shown in FIG.
2;
[0041] FIG. 4 is a front view of the insulator of the heater assembly
shown in FIG. 2;
[0042] FIG. 5 is a front view of a heater assembly of a combined
laundry washing/drying machine according to the present invention;
[0043] FIG. 6 is a front view of an insulator according to a first
preferred embodiment of the present invention;
[0044] FIG. 7 is a cross sectional view taken along a line I-I
of FIG. 6;
[0045] FIG. 8 is a cross sectional view for showing the state in
which the heater coil is mounted to the insulator shown in FIG.
6;
[0046] FIG. 9 is a partially perspective view of an insulator according
to a second preferred embodiment of the present invention;
[0047] FIG. 10 is a front view of the insulator shown in FIG. 9;
[0048] FIG. 11 is a side view of the insulator shown in FIG. 9,
to which a heater coil is mounted;
[0049] FIG. 12 is a plan view of the insulator shown in FIG. 9,
to which a heater coil is mounted;
[0050] FIG. 13 is a partially perspective view of an insulator
according to a third preferred embodiment of the present invention;
and
[0051] FIG. 14 is a side view of the insulator shown in FIG. 13,
to which a heater coil is mounted.
BEST MODE FOR CARRYING OUT THE INVENTION
[0052] Reference will now be made in detail to preferred embodiments
of the present invention, examples of which are illustrated in the
accompanying drawings. In the embodiments, like parts are shown
by corresponding reference numerals throughout the drawings, and
additive explanation thereof will be omitted.
[0053] FIG. 5 is a front view of a heater assembly of a combined
laundry washing/drying machine according to the present invention.
As shown in FIG. 5, the heater assembly 10 of the present invention
includes a housing 11 provided in a blast duct 8 of the combined
laundry washing/drying machine shown in FIG. 1, a supporting plate
16 disposed within the housing 11, a heater coil 40 receiving a
power for generating heat, and an insulator 30 for supporting the
heater coil 40 to electrically isolate the heater coil 40 from the
supporting plate 16. The structure of the housing 11, supporting
plate 16 and heater coil 40 is similar to that shown in FIG. 2,
and thus the detailed description thereof will be omitted.
[0054] The manner of mounting the heater coil 40 to the insulator
30 is different from that shown in FIG. 2. Specifically, the insulator
30 is formed in a plate shape, in which the conventional insulator
is arranged parallel with a longitudinal direction of the heater
coil 40, while the insulator of the present invention is arranged
vertical to the longitudinal direction of the heater coil 40. This
difference is due to the structure of the insulator 30 of the present
invention 30, and embodiments of the insulator will now be described
detail.
[0055] First Embodiment
[0056] FIG. 6 is a front view of an insulator according to a first
preferred embodiment of the present invention, FIG. 7 is a cross
sectional view taken along a line I-I of FIG. 6, and FIG. 8 is a
cross sectional view for showing the state in which the heater coil
is mounted to the insulator shown in FIG. 6.
[0057] As shown in FIGS. 6 and 7, the insulator according to the
first embodiment of the present invention includes a body 31, fixing
slots 33 for fixing the body 31 to a supporting plate (indicated
by a reference numeral 16 in FIG. 5), and a coil passing portion
35 through which the heater coil (indicated by a reference numeral
40 in FIG. 5) passes.
[0058] The body 31 is formed in a flat hexahedral shape extending
in one direction, and is made of electrical insulating material.
Preferably, the body 31 has a thickness longer than a pitch of the
heater coil 40, the reason of which will be described hereinafter.
In particular, the body 31 is two and a half times or three times
as thick as the pitch of the heater coil 40.
[0059] The respective fixing slots 33 is formed at a center of
both sides. If the body 31 passes through a hole of the supporting
plate 16 and then is rotated at an angle of approximately 90 degrees,
the supporting plate 16 is inserted into the fixing slots 33, so
that the body 31 is directly secured to the supporting plate 16.
The body 31 may be fixed to the supporting plate 16 by additional
wire disposed between the fixing slot 33 and the supporting plate
16.
[0060] The coil passing portion 35 is a through hole formed in
an end of the body 31. The heater coil 40 loosely penetrates through
the coil passing portion 35. To this end, the coil passing portion
has to have an inner diameter slightly larger than an outer diameter
of the heater coil 40. If the heater coil 40 generates the heat,
a portion of the heater coil 40 inserted into the coil passing portion
35 may be sufficiently expanded in the same ratio as that of the
other portion.
[0061] The coil passing portion 35 is provided at an inner periphery
thereof with a seating surface 36 having a thickness corresponding
to a thickness of the body 31. An outer periphery of the heater
coil 40 is directly seated on the seating surface 36. Since the
length of the seating surface 36 is longer than the pitch of the
heater coil 40, the heater coil 40 can be stably supported on the
seating surface 36.
[0062] In addition, the coil passing portion 35 is provided at
and edge thereof with a divergent rounded surface 37 having a desired
curvature. When the heater coil 40 is inserted into the coil passing
portion 35, the rounded surface 37 prevents the interference between
the heater coil 40 and the coil passing portion 35. In case that
the rounded surface 37 is inserted into the coil passing portion
35, the rounded surface 37 prevents the interference between the
heater coil 40 and the coil passing portion 35 when the heater coil
40 is repeatedly expanded and contracted.
[0063] If the interior space of the housing is divided into upper
and lower spaces by the supporting plate 16, the coil passing portion
35 is formed at both ends of the body 31, respectively.
[0064] A process of mounting the heater coil to the insulator according
to the first embodiment of the present invention will now be described.
[0065] As shown in FIG. 5, one heater coil 40 disposed between
side walls 13 and 14 of the housing 11 is supported by at least
two insulator 30. Specifically, the heater coil 40 is inserted and
penetrates through one opening of the coil passing portion 35, and
then penetrates through another coil passing portion 35. The heater
coil 40 is supported on the seating surfaces 36 of several coil
passing portion 35. The state in which the heater coil 40 is supported
by optional insulator 30 is fully shown in FIG. 8.
[0066] When the heater coil 40 is inserted into the coil passing
portion 35, the rounded surface 37 prevents the heater coil 40 from
being interfered with the edge of the coil passing portion 35, so
that the heater coil 40 is smoothly inserted into the coil passing
portion 35. Since the length of the seating surface 36 is longer
than the pitch of the heater coil 40, the heater coil 40 can be
more stably supported.
[0067] Since the inner diameter of the coil passing portion 35
is longer than the outer diameter of the heater coil 40, the heater
coil 40 can be expanded within the coil passing portion 35 as much
as it can. At that time, a portion of the heater coil 40 may be
interfered with the edge of the coil passing portion 35 upon expanding
and contracting. This phenomenon is prevented by the rounded surface
37.
[0068] According to the first embodiment of the present invention,
therefore, the heater coil 40 can evenly expand and contract over
the entire length thereof. There is no problem in that the heat
stress is concentrated on a particular portion thereof or the heat
is nonuniformly distributed over the entire heater coil.
[0069] Second Embodiment
[0070] FIG. 9 is a partially perspective view of an insulator according
to a second preferred embodiment of the present invention, FIG.
10 is a front view of the insulator shown in FIG. 9, and FIGS. 11
and 12 are side and plan views of the insulator shown in FIG. 9,
to which a heater coil is mounted.
[0071] As shown in FIGS. 9 to 11, the insulator according to the
second embodiment of the present invention includes a body 51 of
a flat-bar shape, fixing slots 53 for fixing the body 51 to the
supporting plate (indicated by a reference numeral 16 in FIG. 5),
and coil seating portions 55 formed at both ends of the body 51.
The body 51 and the coil seating portion 55 are made of electric
insulating material such as ceramic.
[0072] The respective fixing slots 33 is formed at a center of
both sides, the function of which is similar to that of the first
embodiment.
[0073] The coil seating portion 55 is to be inserted into the interior
of the heater coil 40 for supporting the heater coil 40. The coil
seating portion 55 is formed in a circular shape, and has a penetrating
hole 54 at a center thereof. The penetrating hole 54 is to reduce
the consumption of the material used as the insulator 50. Preferably,
an outer diameter of the coil seating portion 55 is almost similar
to an inner diameter of the heater coil 40, so that the heater coil
40 is resiliently supported.
[0074] The coil seating portion 55 is provided on an outer periphery
thereof with a convolution supporting surface 56 for supporting
convolutions of the heater coil 40. To this end, the convolution
supporting surface 56 has a curvature corresponding to that of the
heater coil 40. Preferably, the convolution supporting surface 56
has a rounded corner. When the heater coil 40 is mounted to the
insulator 50, the heater coil 40 is more easily inserted into the
coil seating portion through the rounded corner of the convolution
supporting surface 56.
[0075] The coil seating portion 55 has a thickness `a` thicker
than the pitch of the heater coil 40. Formation of the coil seating
portion 55 to have such a thickness is to prevent the heater coil
40 from being optionally released from the coil seating portion
55. In order to facilitate the insertion of the heater coil into
the coil seating portion 55, the thickness `a` of the coil seating
portion 55 is not significantly thick. Preferably, the coil seating
portion has to be thinner than the thickness of the body 51.
[0076] A seating slot 57 is formed between the coil seating portion
55 and the body 51. The seating slot 57 is to receive a portion
of the heater coil 40, and is formed at front and rear surfaces
of the body 51, respectively. The seating slot 57 has a curvature
corresponding to the curvature of the heater coil 40. The adjacent
first and second convolutions 41 and 42 of the heater coil 40 are
seated on the coil seating portion 55, with the seating slot 57
being interposed between the convolutions. Preferably, a thickness
`b` between the seating slots 57 is equal to or less than the pitch
of the heater coil 40. Since the thickness `b` of the seating slots
57 is thinner than the thickness `a` of the coil seating portion
55, a stepped portion is formed therebetween to provide a stopper
end 58. The stopper end 58 more rigidly supports the heater coil
40.
[0077] The coil seating portion 55 is formed at both ends of the
body 51, respectively. In case of supporting the heater coil 40
by use of one side of the supporting plate 16 only, one end of the
body may be provided with the coil seating portion 55.
[0078] A process of mounting the heater coil to the insulator according
to the second embodiment of the present invention will now be described.
[0079] For the sake of convenience, as shown in FIG. 12, the portions
of the heater coil 40 mounted to the insulator 50 are referred to
as a first convolution 41 and a second convolution 42. The intermediate
portion connecting the first and second convolutions 41 and 42 is
referred to as a connecting portion 43. A distance between the first
and second convolutions 41 and 42 is corresponding to the pitch
of the heater coil 40.
[0080] As shown in FIGS. 11 and 12, the convolution supporting
surface 56 is interposed between the first and second convolutions
41 and 42 of the heater coil 40. The heater coil 40 is depressed
to insert the coil seating portion 55 into the interior of the heater
coil 40.
[0081] Since the corner of the convolution supporting surface 56
is rounded, the first and second convolutions 41 and 42 are naturally
seated to the coil seating portion 55. At that time, the first and
second convolutions 41 and 42 are gradually widened, so that the
deformation occurring upon mounting the heater coil 40 may be reduced.
[0082] According to further insertion of the heater coil 40, the
first and second convolutions 41 and 42 are seated on the seating
slot 57. As the results, the first and second convolutions 41 and
42 are disposed along the outer periphery of the coil seating portion
55. At the same time, the connecting portion 43 between the first
and second convolutions 41 and 42 is seated on the convolution supporting
surface 56. Since the outer diameter of the coil seating portion
55 is corresponding to the inner diameter of the heater coil 40,
the heater coil 40 is rigidly supported to the outer periphery of
the coil seating portion 55. In particular, since the first and
second convolutions 41 and 42 are caught by the stopper end 58,
it prevents the release of the heater coil 40.
[0083] At that time, since the thickness of the coil seating portion
55 is thicker than the pitch of the heater coil 40, the heater coil
40 is released from the coil seating portion 55 by the resilience
thereof, unless the first and second convolutions 41 and 42 are
optionally widened.
[0084] Third Embodiment
[0085] FIG. 13 is a partially perspective view of an insulator
according to a third preferred embodiment of the present invention,
and FIG. 14 is a side view of the insulator shown in FIG. 13, to
which a heater coil is mounted.
[0086] As shown in FIG. 13, the insulator 60 according to the third
embodiment of the present invention is almost similar to the insulator
50 of the second embodiment of the present invention, except that
an inclined surface 69 is further formed at the coil seating portion
65, and has a thickness which is gradually thinned toward an end
thereof, so as to minimize the deformation of the heater coil during
the mounting process.
[0087] Although it is no matter that the inclined surface 69 is
formed any one of front and rear surfaces of the coil seating portion
65, it is preferable to form the inclined surface 69 on both surfaces
of the coil seating portion. When the heater coil 40 is mounted
on the insulator 60, the heater coil 40 is gradually widened along
the inclined surface 69. Therefore, the inclined surface to advantageously
prevents the deformation of the heater coil during the mounting
process thereof.
[0088] While the present invention has been described and illustrated
herein with reference to the preferred embodiments thereof, it will
be apparent to those skilled in the art that various modifications
and variations can be made therein without departing from the spirit
and scope of the invention. Thus, it is intended that the present
invention covers the modifications and variations of this invention
that come within the scope of the appended claims and their equivalents.
[0089] Industrial Applicability
[0090] With the heater assembly of the present invention, the heater
coil loosely penetrates through the coil passing portion. The heater
coil freely expands and contracts within the coil passing portion,
and it prevents that the heater coil interferences with the coil
passing portion by the rounded surface. Therefore, the heater coil
can evenly expand and contract over the entire length thereof. There
is no problem in that the heat stress is concentrated on a particular
portion thereof or the heat is nonuniformly distributed over the
entire heater coil.
[0091] In addition, the heater coil is supported along the convolution
supporting surface, and simultaneously is inserted into the seating
slot, so that it resiliently supports the outer periphery of the
coil seating portion. This process is achieved by only pressing
the heater coil, thereby easily implementing the mounting operation
of the heater coil. Since the inclined surface is formed on the
coil seating portion, the heater coil is not deformed during the
mounting process. Accordingly, the present invention minimizes the
deformation occurring when the heater coil is mounted to the insulator. |