[0001] The present invention relates to a tumble dryer having improved soundproofing characteristics.
[0002] Household clothes drying machines typically comprise a sheet-steel rotating drum,
in which clothes are tumbled as hot air is circulated therethrough to remove moisture
from and dry the clothes. As the clothes tumble within the dryer drum, they keep falling
against the wall of the drum wall, wherein heavier clothing items, as well as buttons,
zippers and other metal or, anyway, hard ornaments that may be associated with the
clothes being dried or hanging loose thereamong (e.g. coins) have a tendency to strike
against the dryer drum wall and generate noise in the course of the drying process.
Furthermore, the drum works in this case as a resonant chamber, so that the level
of the thus generated noise is eventually boosted.
[0003] A need is therefore felt for the noise generated by clothes and other items tumbling
within the dryer drum to be suitably reduced.
[0004] As a result, in view of solving this problem, the drum is usually designed to feature
an increased wall thickness. This however means also a corresponding increase in the
overall weight of the drum, thereby making it certainly more difficult to perform
the assembly process. In addition, providing the drum with a greater thickness of
its walls causes manufacturing costs to increase accordingly.
[0005] To compensate for or reduce the noise generated by the clothes and items being tumbled
in the dryer drum, a possible known solution lies in the use of sheets of plastic
foam to line the inner surface of the peripheral wall of the dryer drum as a soundproofing
means. The problem with these dryers, however, is that the foamed plastic selected
for the application shall be such as to properly withstand the certainly high temperatures,
which it will be exposed to during drying; furthermore, it may be difficult to assemble
such material inside the drum, whereby the final cost of the dryer would ultimately
be affected resulting in a higher selling price.
[0006] In another attempt to reduce the noise generated by the articles tumbling within
a clothes dryer, use is made of a rotating dryer drum having walls made of multi-layer
sheet-metal featuring a plastic material sandwiched between metal sheets. While this
solution does not involve the use of a foamed-plastic sheet to be attached so as to
line the inside surface of the dryer drum wall, the use of a laminated dryer drum
wall, comprising two sheet-steel plates having to be bonded together through the interposition
of a resin material sandwiched therebetween, does anyway imply a drum structure that
is rather complicated to manufacture, under an unavoidable increase in manufacturing
costs and, ultimately, in the selling price of the clothes dryer.
[0007] Document
EP-A-1541741 discloses a tumble dryer with sound damping covering according to the preamble of
claim 1.
[0008] Accordingly, there is a need for a clothes dryer with enhanced soundproofing characteristics
to be provided, which will on the other hand not require any significant departure
from existing dryer drum constructions, thereby adding to a relatively small extent
to the overall manufacturing costs of the clothes dryer.
[0009] Accordingly, the present invention is directed to a laundry dryer that substantially
obviates the problems arising from typical limitations and disadvantages of prior-art
machines in this connection.
[0010] It is therefore an object of the present invention to provide a laundry dryer having
a structure that can prevent vibration and noise from being incurred in the drum.
[0011] According to the present invention, this aim, along with further ones that will become
apparent from the following disclosure, is reached in a clothes dryer incorporating
the features as defined and recited in the claims appended hereto.
[0012] Features and advantages of the present invention will anyway be more readily understood
from the description that is given below by way of nonlimiting example with reference
to the accompanying drawings, in which:
- Figure 1 is a front-elevational perspective view of the drum of a tumble dryer according
to the present invention;
- Figure 2 is a rear-elevational perspective view of the drum of a tumble dryer according
to the present invention.
[0013] The tumble dryer is provided with an outer casing adapted to allow the control panel
of the machine to be mounted thereon, as well as a rotating drum 2 to be accommodated
therein along with motor and blower means.
[0014] Such outer casing has a front wall provided with a door enabling the user to gain
access to the interior of the drum through an access opening. The drum 2 is mounted
inside this casing for rotation about its central axis, as driven by a motor arranged
to drive the drum by means of a belt.
[0015] Within said outer casing, the drum 2 is also arranged so as to be located in an air
flowpath, thereby enabling dry heated air to be forced therethrough to remove moisture
from the clothes being tumbled therein.
[0016] The drum 2 is comprised of a cylindrical side wall 3 made of metal, in particular
stainless steel, on the inner surface of which there are applied so-called lifters
4, specially provided to assist the clothes in being properly tumbled, a front flange
11 with a clothes access opening and a rear flange 5, both made of metal.
[0017] The drum is made in a single-piece unitary construction and the rear flange is mechanically
connected to a shaft 6 about which the drum 2 is adapted to rotate.
[0018] In a central portion of the rear flange 5, around the rotating shaft 6, there are
provided a plurality of holes 7 for the drying air to be able to pass therethrough.
[0019] In an alternative embodiment the drum can be comprised of a cylindrical side wall
3 rotatably fitted to a front flange 11 and a rear flange 5, which are stationary
relative to the outer cabinet and the cylindrical side wall 3. There are sealing members
fitted between the front flange 11 and the cylindrical side wall 3, and the rear flange
5 and the cylindrical side wall 3, both make relative motion, for preventing of leakage.
The rear flange 5 is fitted with air supply means in communication with the inside
of the drum 2 for supplying a heated air flow to the inside of the drum 2.
[0020] In an advantageous manner, the tumble dryer comprises at least a sound-damping covering
8 associated to the external surface of the drum 2 for absorbing the sound waves generating
from the impingement noise of the articles that are tumbled inside the drum during
dryer operation, wherein said sound-damping covering 8 includes a metal sheet 9 and
an adhesive layer 10 interposed between the sheet 9 and the external surface of the
drum 2.
[0021] The sound waves that are generated by the pulse-like occurrences deriving from the
clothes, and in particular the hard or metal items associated thereto, such as for
instance buttons or zippers, impinging against the inner surface of the metal wall
of the rotating drum 2 are for the most part absorbed by the adhesive layer 10 which,
by the effect of its viscoelastic properties, substantially converts these sound waves
and vibrations into heat, thereby heating up the adhesive layer 10.
[0022] On the other hand, the sound waves that succeed in passing through and issuing from
the glue layer 10 are transmitted to the metal sheet 9, where they undergo further
damping.
[0023] The sound-damping covering 8 created by the adhesive layer 10 and the metal sheet
9 forms a system that is able to damp and absorb sound waves propagating within a
given frequency range, which depends on the characteristics of the adhesive layer
10 and the metal sheet 9.
[0024] In particular, it has been found that an adhesive layer having a thickness ranging
from 100 to 300 µm and a surface density ranging from 50g/m
2 to 150g/m
2, proves particularly effective in absorbing sound waves with a frequency lying within
a range of 500 to 10000 Hz, which are typical frequencies of the noise generated by
clothes impinging against the walls of the drum 2. It has on the other hand been found
that a metal sheet 9 having a thickness ranging from 150 to 300 µm optimally combines
with an adhesive layer 10 having the characteristics as indicated above.
[0025] It has in practice been found that the more the thicknesses of the drum wall (cylindrical
side wall 3, front flange 11, and rear flange 5) and the metal sheet 9 are similar
to each other, if not preferably equal to each other, the more effective are the sound-wave
damping and absorption characteristics thereof.
[0026] It has furthermore been found that the effectiveness in absorbing the sound waves
is the greatest one when use is made of a metal sheet 9 that is made of the same metal
material as the drum 2. For instance, in the case of a drum 2 made of stainless steel,
a metal sheet 9 that is itself made of stainless steel would ensure the best sound-wave
absorption performance.
[0027] An adhesive layer 10 formed of silicone-based or acrylic glue has proven particularly
effective thanks to both the viscoelastic properties thereof and the fact that such
glues can be used in a temperature range from -40°C to 180°C while keeping their sound-wave
absorption and damping characteristics unaltered in the long term notwithstanding
the temperature variations, which they are subject to during drying processes.
[0028] In addition, such glues prove as being particularly effective when working at the
typical temperatures reached by the walls 3,5 of the drum 2 during the drying cycles
and also in case of overheating due to operation irregularity or failure.
[0029] Moreover, the adhesive layer 10 enables the metal sheet 9 to be attached to the drum
2 in a quick manner, without any use of fastening means whatsoever, such as screws
or the like, being required, actually.
[0030] In a particularly advantageous embodiment, which is illustrated in Figure 1, the
drum 2 is clad with a plurality of sound-damping covering members 8 that substantially
cover most of the external cylindrical surface of the drum 2, so as to be able to
maximize the sound-wave absorption effect. The adhesive layer 10 is preliminarily
applied to the surface of the metal sheet 9 that is due to be associated to the external
surface of the drum 2. Then, the metal sheet 9 is glued onto the external cylindrical
surface of the drum 2.
[0031] Alternatively, the sound-damping covering 8 may be comprised of a single member that
is wrapped around and applied on to the external cylindrical surface of the drum 2
along the entire circumference thereof, so as to almost entirely cover such surface.
[0032] In a highly preferred manner, according to the invention, further to the external
cylindrical surface of the drum 2, the sound-damping covering 8 is also associated
to the external surface of the front flange 11 and the rear flange 5 of the same drum
2, as shown in figure 1 and 2, wherein said sound-damping covering 8 may even in this
case be provided in the form of either a single piece or a plurality of sound-damping
coverings 8 applied to said front and rear flange 11,5.
[0033] In a particular embodiment of the present invention, the cylindrical side wall 3
of the drum 2 is made of a polymer material, whereas the rear flange 5, connected
to the rotating shaft 6, is made of metal material, in particular stainless steel,
and the sound-damping covering 8 is solely associated to said rear flange 5 and not
to the cylindrical side wall 3. Expediently the sound-damping covering 8 can also
be provided on the front flange 11.
[0034] Conclusively, it can therefore be stated that the tumble dryer according to the present
invention effectively reaches its basic aim by providing a tumble dryer having a drum
with improved sound-damping characteristics.
[0035] The sound-damping covering according to the present invention, further to being most
effective in absorbing and damping sound waves generating from the clothes and associated
items impinging against the inner wall of the drum, is very simple to manufacture
and attach to the drum, thereby doing away with the drawback usually shared by prior-art
machines.
1. Tumble dryer including a rotating drum (2) mounted within an outer casing and adapted
to receive articles to be dried, said drum (2) comprising a cylindrical side wall
(3), a front flange (11) with a clothes access opening, and a rear flange (5), and
at least a sound-damping covering (8) associated to the external surface of the drum
(2) for absorbing the sound wave produced by the articles being tumbled inside said
drum (2) and impinging against the wall thereof during dryer operation, said sound-damping
covering (8) including a metal sheet (9) and an adhesive layer (10) interposed between
the sheet (9) and the external surface of the drum (2), characterized in that one or more of said sound-damping covering (8) are solely associated to the external
surface of the rear flange (5) and/or the front flange (11) of the drum (2).
2. Dryer according to claim 1, wherein the cylindrical side wall (3) of the drum (2)
is made of a polymer material, whereas the rear flange (5) is made of metal material,
and the sound-damping covering (8) is associated to the external surface of said rear
flange (5).
3. Dryer according to claim 1 or 2, wherein said adhesive layer (10) has a thickness
ranging from 100 to 300 µm.
4. Dryer according to claim 3, wherein said adhesive layer (10) has a surface density
in the range from 50g/m2 to 150g/m2.
5. Dryer according to claim 4, wherein said metal sheet (9) has a thickness in the range
from 150 to 300 µm.
6. Dryer according to claim 4, wherein said metal sheet (9) has the same thickness as
the walls (3, 5, 11) of the drum (2),
7. Dryer according to any of the preceding claims, wherein said metal sheet (9) and said
drum (2) are made of the same metal material.
8. Dryer according to any of the preceding claims, wherein said adhesive layer (10) is
comprised of a silicone-based and/or acrylic glue.
1. Wäschetrockner mit einer rotierenden Trommel (2), die in einem Außengehäuse montiert
und geeignet ist, zu trocknende Artikel aufzunehmen, wobei die Trommel (2) eine zylindrische
Seitenwand (3), einen vorderen Flansch (11) mit einer Kleiderzugangsöffnung und einen
hinteren Flansch (5) umfasst, ferner mindestens eine schalldämpfende Abdeckung (8),
die mit der Außenfläche der Trommel (2) verbunden ist, um die von den in der Trommel
(2) zu trocknenden und während des Trockenvorgangs gegen die Wand derselben prallenden
Artikeln produzierte Schallwelle zu absorbieren, wobei die schalldämpfende Abdeckung
(8) ein Metallblech (9) und eine Klebeschicht (10) umfasst, die zwischen dem Blech
(9) und der Außenfläche der Trommel (2) eingefügt ist, dadurch gekennzeichnet, dass eine oder mehrere der schalldämpfenden Abdeckungen (8) nur mit der Außenfläche des
hinteren Flansches (5) und/oder des vorderen Flansches (11) der Trommel (2) verbunden
sind.
2. Trockner gemäß Anspruch 1, wobei die zylindrische Seitenwand (3) der Trommel (2) aus
einem Polymermaterial gefertigt ist, während der hintere Flansch (5) aus metallischem
Material gefertigt ist und die schalldämpfende Abdeckung (8) mit der Außenfläche des
hinteren Flansches (5) verbunden ist.
3. Trockner gemäß Anspruch 1 oder 2, wobei die Klebeschicht (10) eine Dicke zwischen
100 und 300 µm aufweist.
4. Trockner gemäß Anspruch 3, wobei die Klebeschicht (10) eine Oberflächendichte zwischen
50 g/m2 und 150 g/m2 aufweist.
5. Trockner gemäß Anspruch 4, wobei das Metallblech (9) eine Dicke zwischen 150 und 300
µm aufweist.
6. Trockner gemäß Anspruch 4, wobei das Metallblech (9) die selbe Dicke wie die Wände
(3, 5, 11) der Trommel (2) aufweist.
7. Trockner gemäß einem der vorangehenden Ansprüche, wobei das Metallblech (9) und die
Trommel (2) aus dem selben Metallmaterial gefertigt sind.
8. Trockner gemäß einem der vorangehenden Ansprüche, wobei die Klebeschicht (10) aus
einem Klebstoff auf Silikon- und/oder Akrylbasis zusammengesetzt ist.
1. Sèche-linge comprenant un tambour rotatif (2) monté à l'intérieur d'une enveloppe
extérieure et adapté pour recevoir des articles à sécher, ledit tambour (2) comprenant
une paroi latérale cylindrique (3), un flanc avant (11) avec une ouverture d'accès
aux vêtements, et un flanc arrière (5) et au moins un revêtement amortissant les sons
(8) associé à la surface externe du tambour (2) pour absorber la vague de sons produite
par les articles qui sont culbutés à l'intérieur dudit tambour (2) et se heurtant
contre la paroi de celui-ci pendant l'opération de séchage, ledit revêtement amortissant
les sons (8) comprenant une feuille de métal (9) et une couche adhésive (10) interposée
entre la feuille (9) et la surface externe du tambour (2), caractérisé en ce que un ou plusieurs desdits revêtements amortissant les sons (8) sont seulement associés
à la surface externe du flanc arrière (5) et/ou du flanc avant (11) du tambour (2).
2. Sèche-linge selon la revendication 1, dans lequel la paroi latérale cylindrique (3)
du tambour (2) est faite d'une matière polymère, tandis que le flanc arrière (5) est
fait d'une matière métallique, et le revêtement amortissant les sons (8) est associé
à la surface externe dudit flanc arrière (5).
3. Sèche-linge selon la revendication 1 ou 2, dans lequel ladite couche adhésive (10)
a une épaisseur allant de 100 à 300 µm.
4. Sèche-linge selon la revendication 3, dans lequel ladite couche adhésive (10) a une
densité de surface de l'ordre de 50g/m2 à 150g/m2.
5. Sèche-linge selon la revendication 4, dans lequel ladite couche de métal (9) a une
épaisseur de l'ordre de 150 à 300 µm.
6. Sèche-linge selon la revendication 4, dans lequel ladite couche de métal (9) a la
même épaisseur que les parois (3, 5, 11) du tambour (2).
7. Sèche-linge selon l'une quelconque des revendications précédentes, dans lequel ladite
couche de métal (9) et ledit tambour (2) sont faits de la même matière métallique.
8. Sèche-linge selon l'une quelconque des revendications précédentes, dans lequel ladite
couche adhésive (10) est composée d'une colle à base de silicone et/ou d'une colle
acrylique.