Abstrict
The invention relates to a method and a system of manufacturing
an electric heater (1) intended for heating foam-molded cushions
for e.g. vehicle seats or mattresses, said heater (1) comprising
an electric conductor (2) which preferably consists of an insulated
or non-insulated metal wire. The method comprises the steps of arranging
a plurality of protruding members (10) forming part of a conductor
layout structure (9) in a pattern adapted to the configuration of
the heater (1), arranging a conveyor (13) which is equipped with
a follower (14) along a track (13) which essentially corresponds
to the desired configuration of the heater (1) around said protruding
member (10), and moving said conveyor (13) while said follower (14)
deposits said conductor (2) along said track.
Claims
What is claimed is:
1. A method of manufacturing an electric heater used for heating
foam-molded cushions, wherein said heater is formed of an electric
conductor, which said electric conductor is one of an insulated
and non-insulated wire, comprising the steps of:
arranging a plurality of protruding members having first and second
parts so as to form part of a conductor layout structure in a pattern
adapted to a desired configuration of the heater, said protruding
member second part being rotatable about the vertical axis of said
protruding member;
arranging a continuous flexible conveyor around said protruding
members in a pattern of a path which corresponds to the same desired
configuration of the heater, said continuous flexible conveyor provided
with a follower attached thereto, said follower for facilitating
the deposition of said electric conductor around said protruding
members; and
arranging said continuous flexible conveyor in said path so that
said follower deposits said conductor in said pattern, wherein said
protruding members form a part of a first fixture for the heater.
2. A system for the manufacture of an electric heater intended
for heating cushions, said heater comprising an electric conductor
comprising one of an insulated and non-insulated wire, characterized
in that said system comprises a conductor layout structure comprising
a plurality of protruding members having first and second parts
arranged in a pattern corresponding to the desired configuration
of said heater, said protruding member second part being rotatable
about the vertical axis of said protruding member, a continuous
flexible conveyor arranged about said protruding members in said
desired configuration, said continuous flexible conveyor having
a follower attached thereto, said follower being arranged to deposit
said conductor in said pattern.
3. A method of manufacturing an electric heater used for heating
foam-molded cushions, wherein said heater is formed of an electric
conductor, which said electrical conductor is one of an insulated
and non-insulated metal wire, comprising the steps of:
arranging a plurality of protruding members having first and second
parts so as to form part of a conductor layout structure in a pattern
adapted to a desired configuration of the heater, said protruding
member first part being stationary and said protruding member second
part being rotatable about the vertical axis of said protruding
member;
arranging a continuous flexible conveyor around said protruding
members second parts in a pattern of a path which corresponds to
the same desired configuration of the heater, said continuous flexible
conveyor provided with a follower attached thereto, said follower
for facilitating the deposition of said electric conductor around
said protruding members first parts; and
moving said continuous flexible conveyor in said path so that said
follower deposits said conductor in said pattern, wherein said protruding
members form a part of a first fixture for the heater.
4. A system for the manufacture of an electric heater intended
for heating cushions, said heater comprising an electric conductor
comprising one of an insulated and non-insulated wire, characterized
in that said system comprises a conductor layout structure comprising
a plurality of protruding members having first and second parts
arranged in a pattern corresponding to the desired configuration
of said heater, said protruding member first part being stationary
and said protruding member second part being rotatable about the
vertical axis of said protruding member, a continuous flexible conveyor
arranged about said protruding members second partss in said desired
configuration, said continuous flexible conveyor having a follower
attached thereto, said follower being arranged to deposit said conductor
in said pattern.
Description The present invention relates to a system and a method for manufacturing
an electric heater, preferably of the kind described in the Swedish
patent application No. 9402508-7 which is included herein by way
of reference A heater of this type is primarily intended for heating
foam-molded cushions for e.g. vehicle seats or mattresses. The heater
comprises an electrical conductor which preferably consists of an
insulated or non-insulated metal wire for electrically heating the
foam-molded cushion.
One object of the present invention is to make it possible to manufacture
a heater of the kind outlined above in a simple and rapid manner.
This object is obtained by means of a system and a method for manufacturing
an electric heater presenting the characteristics defined in the
appended claims.
Currently preferred embodiments of the present invention will be
described in the following in closer detail with reference to the
accompanying drawings, wherein like numeral references have been
used in the different drawing figures to denote functionally equivalent
parts.
FIG. 1 illustrates schematically one example of a foam-molded cushion
including a heater manufactured in accordance with the inventive
method and/or while using the inventive system.
FIG. 2 illustrates schematically one example of the various steps
of the inventive method for the manufacture of the heating device.
FIG. 3 illustrates schematically one example of an inventive conductor
lay-out structure for a heater in accordance with a first embodiment.
FIG. 4 illustrates schematically one example of an alternative
embodiment a holder arrangement included in a conductor lay-out
structure.
FIG. 5 illustrates schematically one example of an inventive pick-up
structure.
FIG. 6 illustrates schematically in a broken sectional lateral
view the manner in which a part of the pickup structure in accordance
with one embodiment is lowered on top of a conductor deposited by
a conductor lay-out structure.
FIG. 7 illustrates schematically in a broken sectional lateral
view the manner of engagement of parts of the pick-up structure
with a conductor lifted off a conductor lay-out structure.
FIG. 8 illustrates schematically in a view from below and in a
broken sectional view the manner of engagement of the pick-up structure
lowered on top of the conductor lay-out structure with a conductor
positioned in the conductor lay-out structure.
FIG. 9 illustrates schematically a fixation structure in accordance
with one embodiment of the invention.
FIG. 10 illustrates schematically the manner in which the pick-up
structure in accordance with one embodiment of the invention transfers
the deposited conductor from a conductor lay-out structure to a
fixation structure and further to a transportation package.
FIG. 11 illustrates schematically in a broken sectional lateral
view a part of a pick-up structure including a conductor disposed
in a fixation structure.
FIG. 12 illustrates schematically a fixation structure in accordance
with an alternative embodiment.
FIG. 13 illustrates an example of a band formed by a conductor
and consisting of a plurality of loops that are interconnected by
local interconnections.
FIG. 1 is a perspective view of a seat cushion in which a heater,
generally designated by 1, is for instance mainly embedded by molding.
The heater 1 comprises at least one electrical conductor 2 the ends
3, 4 of which are electrically connected by means of contacts (not
shown) to a source of electricity (not shown). The heating effect
is produced by electric current being conducted through an electrical
conductor 2 having suitable resistivity. As is easily understood
it is possible to embed heaters 1, in the molding operation proper,
also in other types of components, such as the backrest of a vehicle
seat, armrests or in a mattress. As is likewise easily understood
it is possible to embed the heater 1 in a part component of a cushion
or the like, or to dispose for instance an essential part of the
heater 1 intermediate part components, cushions or the like which
components are later interconnected for instance by gluing or fusion,
a method which provides essentially the same technical effect as
by cast-in embedment of the heater 1. For more information regarding
the technical advantages gained by arranging the heater 1 in a cushion
or mattress in the manner indicated reference is made to the above-mentioned
Swedish application No. 9402508-7.
FIGS. 1 and 13 show one example of a configuration of the lay-out
of the heater 1 which heater in accordance with these examples has
received its configuration as a result of the conductor 2 having
been arranged in one or several bands 5 of closely juxtaposed bights,
each one of which comprises a loop 6 and an open portion 7 facing
away from said loop. In accordance with the shown embodiments adjacent
loops 6 that are turned in the same direction essentially are in
contact with one another at points of contact 8. However, it is
easily understood that several modifications of the lay-out of the
conductor 2 are possible, and examples of other modifications are
shown for instance in the above-mentioned Swedish application No.
9402508-7,wherein the advantage of arranging the conductor in bights
is also described.
At least parts of the heater 1 and preferably essentially all said
open portions 7 or essentially all said points of contact 8 are
locally interconnected in accordance with a preferred embodiment
in order to form one or several connected bands 5 and consequently
an essentially contiguous heater 1. The technical advantages gained
by connected bands 5 and consequently by an essentially contiguous
heater 1 appear from the above-mentioned Swedish patent application
No. 9402508-7.The interconnection may be achieved for instance by
means of gluing, welding, sewing or taping. FIG. 13 shows one example
of establishing the interconnection with the aid of strips 23 and
24, for instance glue strands or strips of tape.
FIG. 2 illustrates the different principal steps for the manufacture
of a heater in accordance with one embodiment of the inventive method.
In accordance with this embodiment the deposition of a conductor
2 is prepared in step 1 by arranging a plurality of protruding members
forming part of a conductor lay-out structure in a pattern that
is adapted to the configuration of the heater 1, and by positioning
a conveyor which is equipped with a follower member in the pattern
of a path essentially agreeing with the desired configuration of
the heater 1 around said protruding members. The conductor 2 is
also interconnected with the follower means. In step 2, the conveyor
is set in motion whereby the follower means will deposit the conductor
2 in said pattern, the protruding members forming part of a first
fixture for the heater 1. The steps included in the method of FIG.
2 and the steps of other inventive methods will be described in
the following with reference to the other appended drawing Figures.
FIG. 3 illustrates one example the conductor lay-out structure
generally designated by 9 comprising a system for the manufacture
of a heater 1. The conductor lay-out structure 9 comprises a plurality
of protruding members generally designated by 10. Each protruding
member 10, in accordance with the embodiment shown, has a lower
part surrounded by a bearing 11, and an upper part 12. The upper
part 12 preferably comprises a bevelled face 19 extending along
the peripheral face at the upper end as seen in FIG. 3.
A conveyor 13, which in accordance with the embodiment illustrated
is a belt conveyor, is arranged between the lower bearing part of
the protruding members 10 so as to extend along a path essentially
corresponding to the pattern of the heater 1 to be manufactured.
The conveyor 13 is formed with a follower means 14 supporting a
conductor 2. The end 70 of the conductor 2 preferably is connected
to a conductor supply reel or the like (not illustrated) for essentially
continuous supply of the conductor 2 to be deposited in the conductor
lay-out structure 9. Preferably, the conveyor 13 extends continuously
along said protruding members 10 and is connected to a device (not
shown) which could be e.g. motor operated, to actuate the conveyor
13 for movement thereof. At one part of the conductor lay-out structure
9 a holder arrangement, generally designated by 15, is provided.
In accordance with FIG. 3 the holder arrangement 15 comprises three
holding devices 16, 17 and 18, each one of which is actuated by
e.g. pneumatic means (not shown), for independent, individual movement
between a locking position in which they each one holds fast a conductor
2 deposited beyond or through the holding device 16, 17, 18, and
a release position, in which the conductor 2 is not so held fast.
In accordance with a preferred embodiment the holding device 17
also includes a severing means (not shown) to cut off or otherwise
produce an interruption in the conductor 2.
FIG. 4 illustrates a holder arrangement 15 in accordance with a
second preferred embodiment. The holding devices 16, 17 and 18 are
movable in the direction indicated by arrows A, B and C, respectively,
between said locking and release positions. In this case dashed
lines indicate a severing means 21 which is movable in the direction
indicated by arrow D, between the illustrated position and a position
wherein said device produces a disconnection in the conductor 2.
The e.g. semi-circular body 20, about which the conveyor 13 including
its following means 14 is arranged, preferably is formed with a
bevelled face or a back-up face in the area of severence to facilitate
the cutting-off of the conductor 2.
The conductor lay-out structure 9 functions in the following manner.
In accordance with the examples illustrated in FIGS. 3 and 4, the
direction of movement of the conveyor 13 is counter-clockwise. In
the starting position (not shown) the conductor 2 is held fixedly
by the holding device 17, the conveyor 13 is at a stand-still, and
the follower means assumes a position between the holding device
17 and the holding device 18. The holding devices 16 and 18 assume
their release position. The conveyor 13 is set in motion, and the
follower means 14 deposits the conductor 2 about the upper part
12 of the protruding members 10, above the bevelled face 19 thereon.
The bevelled face 19 on the protruding members 10 prevents the conductor
2 from sliding downwards alongside the protruding members 10 as
seen in FIG. 3. When the follower means 14 moves past the holding
device 18 the latter is shifted to its locking position, whereupon
the holding device 17 is shifted to its release position. The conductor
2 is then released from the holding device 17, for instance through
the inherent resilience of the conductor 2 or with the aid of a
means (not shown) for release thereof. One end 2 of the conductor
2 and thus of the heater 1 is held fast by the holding device 18
in a first point in the area of one end 4 of the conductor 2 during
the laying-out or deposition operation.
The follower means 14 is moved past and around the rest of the
protruding members 10, which members are disposed in a pattern matching
the configuration of the heater 1, during which movement the follower
means 14 deposits the conductor 2 along the path formed by the conveyor
13, which path essentially corresponds to the desired configuration
of the heater 1 (see for example FIGS. 1 or 13).
When the follower means 14 passes the holding device 16 the latter
is shifted to its locking position, holding the conductor 2 fixedly
in a second point in the area of the second end 3 of the conductor
2 and thus of the conductor lay-out structure 1.
The follower means 14 is then moved past the holding device 17,
the latter then being shifted to the locking position. The conveyor
13, and thus the follower means 14, are stopped, bringing the follower
means 14 to a stand-still between the holding devices 17 and 18
as illustrated in FIG. 4. The conductor 2 then is severed with the
aid of a suitable means, such as a cutting device 21. In this position,
a conductor 2 is laid out in the conductor lay-out structure 9 in
the desired path configuration around protruding members 10, and
the conductor 2 is held fixedly in the area of its ends 3, 4 by
the holding devices 16 and 18, respectively. In a cut-off operation
this conductor 2 has been severed from the conductor 2 one end of
which is held fast in the holding device 17 and engaging with the
follower means 14 and the opposite end of which 70 is arranged for
instance about said conductor supply reel, which position is illustrated
in FIG. 3. The conductor lay-out structure 9 thus forms a first
fixture for the conductor 2 deposited in the conductor lay-out structure
9. In accordance with the shown example the conductor 2 has been
positioned along a path in the conductor lay-out structure 9 comprising
several bands 5 of closely juxtaposed bights. The pattern of the
laid-out conductor 2 in FIG. 1 does not exactly agree with the pattern
of the conductor 2 in FIG. 3. The pattern of the laid-out conductor
2 may be varied to suit various purposes, for instance by altering
the path of the conveyor 13, by shifting the positions of the protruding
members 10 or by exchanging one component, such as a plate to which
several or all protruding members 10 are secured, and the lay-out
pattern of the conductor as shown in FIGS. 1 and 3 are merely intended
to show various example of path patterns.
It is easily understood that the conductor 2, the follower means
14, the conveyor 13, the holder arrangement 15 and the protruding
members 10 may be configured differently from that or those shown.
In accordance with the illustrated preferred embodiment the follower
means 14 does not pull the conductor 2 behind, because the friction
that would arise between the conductor 2 and the protruding members
10, should such an arrangement be adapted, would cause problems
in the conductor laying-out operation. Instead, the conductor 2
is supplied from a reel holding conductor material, to the follower
means 14, which deposits the conductor 2 in the desired pattern.
However, it is easily understood that the deposition of the conductor
2 could be performed by means corresponding to follower means, along
said path, when the above mentioned problems of friction between
the conductor 2 and the protruding members 10 do not exist. In accordance
with one embodiment means are provided to prevent too rapid and
too much conductor material 2 to be unreeled from the supply reel
or a corresponding means during the conductor lay-out operation.
This effect may be achieved for instance by applying a braking force
on the reel, which force should be sufficiently weak to allow unreeling
of conductor material 2 when the conveyor 13 is in motion but sufficiently
strong to prevent for instance surplus conductor material to be
unreeled when the conveyor 13 is stopped. In the area of the end
70 of the conductor 2 a follower means (not shown) is provided in
accordance with one embodiment, which follows the movements of the
follower 14 and which is arranged to ensure that the follower 14
is supplied with the conductor 2 at a suitable angle with respect
to the lay-out extension in order to avoid such problems as the
conductor 2 sticking to the follower 14. In accordance with an other
embodiment this problem is avoided by positioning the conductor
supply reel or the equivalent means at such a distance from the
conductor lay-out structure and at such a position that angular
changes during the deposition of the conductor 2 adjacent the follower
will be sufficiently small. However, a conductor supply reel may
be disposed linearly above the conductor lay-out structure in FIG.
1 at said distance from said lay-out structure 9.
When the conductor 2 has been deposited in the manner indicated
for instance in FIG. 3, parts of the heater 1 in accordance with
one embodiment may be inter-connected to produce said essentially
contiguous heater 1. The interconnection may be effected in the
conductor lay-out structure 9 by for instance gluing, welding, sewing
or taping. To facilitate e.g. gluing a support is provided in accordance
with one embodiment at and preferably below the deposited conductor
2 in FIG. 3, against which the interconnection may then be performed.
In accordance with one preferred embodiment the support in the shape
of plates 22 is inserted between the protruding members 10 in the
conductor lay-out structure 9 shown in FIG. 3 illustrated schematically
in FIG. 12 with respect to another structure). In accordance with
one embodiment the protruding members 10 are then formed with bevelled
faces 22 to facilitate insertion of the support and to permit interconnection
at the desired points of interconnection in the conductor 2. At
least in the area of interconnection of the various parts of the
conductor 2 the support may be provided with a surface layer preventing
the conductor 2 from adhering to the support. In accordance with
one embodiment the support is provided with tape which is attached
to the conductor 2 by moving the support towards the conductor 2
into engagement therewith at one of its sides, for instance its
lower face, while at the same time in accordance with one embodiment
a back-up means being displaced towards and into engagement with
the opposite side of the conductor 2, for instance its upper face.
In accordance with one embodiment also the back-up is provided with
a tape, in which case the conductor 2 will be taped from both sides.
As is easily understood the support or the back-up may also be made
use of to facilitate inter-connection by means of e.g. welding or
sewing, and that the support may for instance be part of the protruding
members 10. In the latter case the support may be for instance the
bevelled face 22, which in this case is located slightly spaced
from or at the deposited conductor 2. The connecting material, such
as tape, glue or the material making part of the seam bond, could
also, in accordance with one embodiment, at least partly comprise
areas that is affectable by magnets, such as iron powder, which
may be attached to a magnet for reasons to be explained further
on. In accordance with one embodiment according to which gluing
is used as the interconnection method, a support, such as the plates
22, could at least partly comprise areas of material that is affectable
by magnets, such as iron powder, which material adheres to the glue
used to interconnect parts of the connector 2. As a result of the
interconnection an essentially contiguous heater 1 is produced,
which may be transferred from the conductor lay-out structure 9
while essentially retaining the lay-out pattern imparted to the
conductor.
After the interconnection, the holding devices 16, 18 incorporated
in the conductor lay-out structure 9 are moved to the release position,
whereupon the heater 1 is transferred from the structure 9. A new
conductor 2 may then be deposited in the conductor lay-out structure
9 in the manner indicated above, after said support, for instance
in the form of plates 22, as the case may be and as the need arises
having been removed from the conductor lay-out structure 9.
In accordance with another embodiment a pick-up structure is used,
for instance configured as the one illustrated in FIG. 5, generally
designated by numeral reference 30. The pick-up structure 30 illustrated
in FIG. 5 has six gripping devices 31 four of which are illustrated
schematically. Each gripping device 31 is formed with means 32 designed
to engage with and essentially fix the conductor that has been deposited
in the lay-out structure 9. In accordance with the shown embodiment,
the pattern of the conductor 2 deposited in the conductor lay-out
structure 9 comprises a plurality of bands of closely juxtaposed
bights, each one of which comprises a loop 6 and a open portion
7 facing away from said loop, juxtaposed loops 6 that are turned
in the same direction essentially meeting at points of contact 8.
In the manner illustrated the means 32 may be in the shape of a
plate having teeth 36 thereon and being securely connected to a
rotary shaft 33 (see e.g. FIGS. 6 and 7), which upon actuation of
e.g. a rack 35 cooperating with a gear 34 may be moved between a
position illustrated in FIG. 6, in which the teeth 36 are insertable
between adjacent loops 6 of the conductor deposited by the conductor
lay-out structure 9, and the position illustrated in FIG. 8, wherein
the teeth 36 engage with adjacent loops 6 in the area of the points
of contact 8. The engagement fixes the points of contact 8 between
the teeth 36 and an edge 40 of the gripping device 31. The area
of contact of the edges 40 and/or the teeth 36 with the conductor
2 is coated, in accordance with a preferred embodiment, with a high-friction
coating in order to improve the fixation of the conductor 2 to the
pick-up structure 30. The pick-up structure 30 likewise comprises
a guide 37 to guide the means 32.
When a conductor 2 has been deposited in the conductor lay-out
structure 9 it is picked up in accordance with one embodiment for
instance by the pick-up structure 30 being turned upside down, from
the position illustrated in FIG. 5. The teeth 36 of the pick-up
structure 3 are arranged in the position illustrated in FIG. 6 and
the pick-up structure 3 is lowered down above the structure 9, the
teeth 36 being inserted intermediate adjacent loops 6 of the conductor
2 and in such a manner that the edges 40 will essentially engage
with the conductor 2, whereupon the shafts 33 are rotated to bring
about the engagement between the teeth 36 and the conductor 2, whereby
the lay-out pattern of the conductor 2 is essentially fixed. In
accordance with one preferred embodiment the pick-up structure 30
likewise comprises a holder means (not shown) which is arranged
to hold fast the ends 3, 4 of the conductor 2. When a holder arrangement
15 in accordance with FIG. 4 is used the holder means could comprise
for instance two holders (not shown) arranged to fix the ends 3,
4 of the conductor 2 in the area of points 38 and 39, respectively,
as the pick-up structure 30 is lowered down across the conductor
lay-out structure 9. The holding devices 16, 18 of the conductor
lay-out structure 9 are then moved to their release position, whereupon
the pick-up structure 30, and thus the deposited conductor 2, are
transferred from the structure 9 as illustrated in the left-hand
part of FIG. 10. During the transfer the conductor 2 is held in
its fixed position by the pick-up structure 30 as illustrated in
FIG. 7, the pick-up structure 30 then forming a second fixture for
the heater 1.
Deposition and lay-out of the fresh conductor 2 may be started
in the conductor lay-out structure 9.
The connection of the conductor 2 fixed to the pick-up structure
30 may in accordance with one embodiment be achieved for instance
by means of gluing, welding, sewing or taping it to the pick-up
structure 30. For this purpose the pick-up structure 30 and thus
the conductor 2 are arranged in accordance with one embodiment in
abutment against a support, for instance by lowering the pick-up
structure 30 towards a table in said with respect to FIG. 5 upside-down
position, whereupon connection for instance by means of gluing may
be effected to said support. For this purpose the pick-up structure
30 is formed with recesses 46 through which e.g. gluing means may
be inserted. Also this support may be provided with the above-mentioned
superficial layer to prevent the conductor 2 from being adhering
to the support. It is easily understood that also the support with
tape thereon and/or the back-up means with tape thereon may be used
for tape-attachment of the conductor 2 arranged in the pick-up structure
3. The interconnection material, such as tape, glue or material
comprised in the seam bond, may in this case at least partly comprise
areas of a material that is affectable by magnets, such as iron
powder, for reasons to be explained further on.
In accordance with another embodiment interconnection is achieved
in an interconnection structure for instance of the type illustrated
in FIG. 9 and generally designated by reference numeral 45. The
interconnection structure 45 is formed with members 47 matching
e.g. recesses 46 in the pick-up structure 30, allowing each gripping
device 31 to be disposed between members 47. FIG. 10 illustrates
the turning of the pick-up structure 30 in accordance with this
embodiment upside-down with respect to the position wherein it picks
up the conductor 2 in the conductor lay-out structure 9 and is then
again lowered on top of the interconnection structure 45, ensuring
that the members 47 pass through the recesses 46. In this case the
members 47 support the parts of the conductor 2 to be interconnected,
in order to facilitate the interconnection operation. This situation
also appears from FIG. 11, illustrating a part of the gripping device
31 of the pick-up structure 30 positioned in the interconnection
structure 45, with the conductor 2 in the area of the loops 60 resting
against a support in the form of the members 47. In this case the
pick-up structure 30 forms part of the interconnection structure
45 and the interconnection structure 45 forms a third fixture for
the heating device 1. By means of e.g. gluing or welding the parts
of the conductor 2 in the area of the support are interconnected
in order to produce an essentially contiguous heater 1. At least
in the area of interconnection of the various parts of the connector
2 the support may be provided with a superficial layer 48 preventing
the conductor 2 from being connected to the support. In accordance
with one embodiment the support is provided with tape which is attached
to the conductor 2, whereupon in accordance with one embodiment
the conductor 2 is also taped from the opposite side, for instance
the upper side as seen in FIG. 11. The interconnection material,
such as tape, glue or the material forming part of the seam bond,
may also in accordance with one embodiment at least partly comprise
areas including material that may be affected by magnets, such as
iron powder, for reasons to be explained later on. In accordance
with one embodiment wherein gluing is used as the interconnection
method, a support may for instance at least partly include areas
comprising material that is affectable by magnets, such as iron
powder, which material sticks to the glue used to interconnect parts
of the conductor 2. In accordance with one modification of this
embodiment the surface layer 48 is capable of retaining said material
by magnetic force preparatory to the interconnection step. The gluing
operation secures the material to the glue string and this material
may then be separated from the surface layer 48 when the conductor
2 is moved from the interconnection structure 45. During the interconnection
an essentially contiguous heater 1 is produced, which may be transferred
from the interconnection structure 9 and the pick-up structure 30
while essentially retaining the pattern of lay-out of the conductor.
Following the interconnection, the pick-up structure 30 is moved,
as the case may be, from the interconnection structure 45 in accordance
with FIG. 10 or from the support/back-up members, whereupon the
pick-up structure is again, when necessary, turned upside down and
disposed above a transportation package 50, which may be e.g. a
box, whereupon the shafts 33 and the holding means are actuated
to release the heater 1 from the pick-up structure 30, placing it
in the transporation package 50. In accordance with a preferred
embodiment the transporation package 15 is formed with several protrusions
(not shown) having a configuration matching at least some of the
loops 8 of the heater 1, the heater 1 being separated from the pick-up
structure 30 in such a manner that said loops 8 are placed about
the protrusions, ensuring that the heaters 1 transported inside
the transporation package 50 have an essentially uniform orientation.
Unpacking of the heaters positioned in the transportation package
50 may for instance be accomplished by lowering a frame (not shown)
with projections having a configuration matching the loops 6 of
the heater 1, down into an opened transportation package 50 from
above in such a manner that the projections are inserted into the
loops 6, whereupon the transporation package 50 and the frame are
for instance turned upside down to ensure that the heaters 1 engage
with and are supported by the frame, whereupon the package of transporation
is separated from the frame and the heaters 1 supported thereby.
In accordance with another embodiment a heater 1, consisting of
a non-connected conductor 2 disposed in the pick-up structure 30,
is transferred to an interconnection structure which may for instance
be configured in the manner illustrated in FIG. 12 and is designated
generally by 55. This interconnection structure 55 comprises a plurality
of protruding members 56 about which the conductor 2 is disposed
for instance by means of the pick-up structure 30, for instance
by the pick-up structure 30 being lowered down across the interconnection
structure 55 in such a manner that the loops 6 of the conductor
2 are placed about the protruding members 56 and the conductor 2
is fixed to the interconnection structure 55, whereupon the movable
parts of the pick-up structure 30 are actuated to disengage the
pick-up structure 30 from the conductor 2, the pick-up structure
30 without the conductor 2 then being moved away from the interconnection
structure 55. The protruding members 56 of the interconnection structure
55 are disposed in essentially the same pattern as the protruding
members 10 of the conductor lay-out structure 9, and in accordance
with the shown preferred embodiment they have a configuration identical
to that of the upper part 12 of these protruding members 10. The
interconnection structure 55 also comprises a holder means (not
shown) arranged to fix the ends 3 and 4 of the conductor 2. The
interconnection structure 55 thus forms a third fixture for the
heater 1. The interconnection is achieved also in accordance with
this embodiment in the manner described above with respect to the
interconnection in the case of the conductor lay-out structure 9.
In accordance with one embodiment (not shown) a pick-up structure
is arranged to transfer also part of the conductor lay-out structure
9 together with a non-connected conductor 2 from the structure 9.
For instance, the protruding members 10 may be transferred, or else
the upper part 12 thereof may be transferred from the conductor
lay-out structure 9 to an interconnection structure (not shown),
said interconnection structure then being configured in the manner
illustrated in FIG. 12 with respect to the interconnection structure
55. After having been transferred from the lay-out structure 9,
the lay-out structure 9 is re-established before the conductor deposition
is again started.
After interconnection of parts of the conductor 2 the essentially
contiguous heater 1 in accordance with the teachings above may be
positioned for instance in a transportion package 50 to be further
transported to a cushion or mattress manufacturer or may be transported
directly to the premises where the cushions or mattresses are produced.
In accordance with the above-mentioned preferred embodiment the
interconnection material comprises at least partly areas of a magnet-affectable
material, such as iron powder. This material may be made use of
in order to, by means of one or several magnets in a mould, fix
the essentially assembled heater 1 in the mould during the foam
moulding of the cushion or mattress. The magnet-affectable material
may also, in accordance with one embodiment, be made use of to transport
the unpacked heaters secured to said frame, to the mold. In accordance
with this embodiment use is made for instance of the preferably
flexible plate including magnets which by plate means of magnetic
force, is connected to an upper or outer heater 1 secured to the
frame protrusions and which picks up said heater from the frame,
whereupon the plate and the heater 1 are transferred to the mould
to position the heater 1 between the plate and the mould, whereupon
the plate is pressed against and adopt the configuration of the
mould, whereby the mold is interconnected with the heater 1 by magnetic
force, retaining the latter inside the mould when the plate is removed
from the mould. The force retaining the heater to the mold may be
achieved for instance as a result of the magnetic force of the mold
on the heater 1 being stronger than the magnetic force of the plate
on the heater 1.
In accordance with a preferred embodiment the heater is formed
with at least one sensor (not shown), such as a thermistor, which
may be connected for instance to a means (not shown) to control
the current supply to the heater 1 and/or to a safety means (not
shown) which is triggered in response to a predetermined preset
temperature of the sensor, whereupon the current supply to the heater
1 is interrupted. In accordance with the preferred embodiment the
sensor is arranged at the heater 1 prior to the interconnection
of the parts of the conductor 2, whereby the sensor is connected
to the heater 1 at the same time and preferably in the same manner
as the interconnection of the various parts of the conductor 2.
In accordance with another preferred embodiment the heater 1 comprises
contact means (not shown) at its ends 3,4 for interconnection of
the heater to said source of current.
It is easily understood that the feature of arranging a plurality
of protruding members 10 incorporated in the lay-out structure 9
in a pattern matching the shape of the heater 1, which is achieved
in the prepatory step 1 of FIG. 2, for instance by changing the
position of the protruding members 10, by altering the path of the
conveyor 13 along said protruding members 10, or by changing one
or several inserts to which a plurality of protruding members 10
are attached, preferably is carried out as the production is reset
from the manufacture of heaters 1 having a first lay-out pattern,
to the manufacture of heaters 1 having a second lay-out pattern.
The measures of the prepatory step 1 thus need not always be carried
out before the deposition step 2 in FIG. 2 is initiated. In order
to facilitate said reset, the device for causing the conveyor 13
and/or the holder arrangement 15 to move, is arranged in accordance
with a preferred embodiment, in a separate part of the conductor
lay-out structure 9, the protruding members 10 being arranged at
one or several exchangable parts like the above mentioned inserts.
It is also understood that it is possible to deviate somewhat from
the described embodiments. For instance, the conductor 2 may be
laid-out along said path in a lay-out structure, one end of the
conductor 2 being securely attached to a follower 2, and the opposite
end of the conductor 2 preferably being connected to a supply reel
or the like for essentially continuous supply of conductor 2 to
be deposited by the lay-out structure. The conductor 2 need not
be supplied to the lay-out structure essentially continuously as
is the case when for instance a reel is used. Instead, it is possible
for instance in advance to cut off desired lengths of conductor
material 2, whereupon a cut length of conductor is deposited or
drawn in the desired lay-out pattern by the conveyor.
The pattern of the path of the conductor 2 around the protruding
members in the lay-out structure may also vary within wide limits.
In accordance with the above embodiments the conductor 2 has been
deposited in the form of one or several bands 5 of closely juxtaposed
bights, each bight consisting of a loop 6 and an open portion facing
away therefrom, juxtaposed loops that are turned in the same direction
being arranged in such a manner that they essentially meet at points
of contact 8. However, several alternative lay-out patterns are
possible and it is not necessary, although preferable, to arrange
the conductor 2 in the form of bights. It is easily understood that
the conductor could for instance be deposited in a zig-zag pattern,
in which case protruding members having smaller radii than in accordance
with the above mentioned embodiments may be used.
It is also understood that the appearance and the function of the
pick-up structure and the interconnection structure may be varied
within wide limits and still produce essentially the same technical
effect. All such modifications and varieties that are comprised
by the basic inventive idea should, however, fall within the scope
of the appended claims. |