EP1907616A1

EP1907616A1 - Door for a household appliance, in particular for a front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer

Info

Publication number: EP1907616A1
Application number: EP06795055A
Authority: EP
Inventors: Lucio Amati; Paolo Santonicola; Alessandro Francinella
Original assignee: Indesit Co SpA
Current assignee: Whirlpool EMEA SpA
Priority date: 2005-06-29
Filing date: 2006-06-26
Publication date: 2008-04-09
Also published as: RU2407835C2; WO2007000645A1; RU2008103192A; ITTO20050453A1

Abstract

The present invention relates to a door (20) for a household appliance, in particular for a front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer (1), comprising a plurality of thermoplastic components. According to the invention, at least two thermoplastic components are connected together by welding, preferably by linear vibration welding.

Description

DOOR FOR A HOUSEHOLD APPLIANCE, IN PARTICULAR FOR A FRONT-LOADING OR SUBSTANTIALLY FRONT-LOADING LAUNDRY WASHING MACHINE, WASHING/DRYING MACHINE OR CLOTHES DRYER

DESCRIPTION

The present invention relates to a household appliance door according to the preamble of claim 1. Said door particularly lends itself for installation to a front-loading or substantially front-loading laundry washing machine, washing/drying machine o clothes dryer. The Applicant has studied various household appliance doors, in particular various doors for front-loading or substantially front-loading laundry washing machines, washing/drying machines or clothes dryers, which consist of an assembly of at least two structural components made of a thermoplastic material. Such structural components are used to hold a further component in between them, in particular a glass door bowl which, being transparent, allows the user to see inside the appliance even when the door is closed. Said structural components may be locked together so as to form a single body or joining them together using mechanical devices, e.g. securing screws. Whichever of the above solutions is adopted for the connection between the thermoplastic structural components comprised in the household appliance door, the Applicant has found a number of drawbacks. First of all, the connection turns out to be rather weak, thus causing a creaking sound when the door is moved, a creaking sound which is subject to increase during the life of the household appliance, considerably reducing the quality perceived by user. Moreover, when assembling the door the forces necessary to ensure the connection between the thermoplastic structural components (e.g. tightening torque by screwing in the securing screws) brings about, where said forces are applied, a considerable tension state which deforms the thermoplastic structural components (with negative consequences on the door appearance) and which sometimes may even cause failures of at least one structural component.

The object of the present invention is to overcome the above drawbacks through an innovative household appliance door, adapted to be installed preferably in a front- loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer.

The household appliance door adapted to attain said object incorporates the features set out in the annexed claims, which form an integral part of the present description. The present invention is based on the idea of a door for a household appliance, in particular a door for a front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer, comprising a plurality of thermoplastic components and characterized in that at least two of said thermoplastic components are connected together through welding. The welding creates a nonremovable connection which replaces the traditional removable mechanical connections (such as, for instance, connections through securing screws or joints), which operate by interference. In order to weld together said at least two thermoplastic components, one may use any welding technique (vibration welding, ultrasonic welding, heat seal, infrared welding, laser welding or spot welding) nowadays well known to engineers working in the industry of polymeric materials.

The present invention will become apparent, together with its further advantages, from the following detailed description and from the annexed drawings, which are supplied by way of non-limiting example, wherein:

• Fig.l shows schematically a possible embodiment of a household appliance door according to the present invention, said door being in particular installed to a front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer; • Fig.2 is a schematic exploded view of a possible embodiment of a household appliance door according to the present invention and

• Fig.3 shows schematically a particular thermoplastic component included in the possible embodiment of the household appliance door according to the invention illustrated in Fig.2, more precisely the component called "rear element" in the following detailed description.

Fig.l illustrates a laundry washing machine, washing/drying machine or clothes dryer 1 adapted to carry out typically at least one washing and/or drying treatment, in particular said laundry washing machine, washing/drying machine or clothes dryer 1 being a front-loading machine. The laundry washing machine, washing/drying machine or clothes dryer 1 comprises:

• a cabinet, in turn comprising a front face 4; • a tub for containing water or wash liquid;

• a drum for containing textile items, which can be rotated about its axis through a motor device;

• a door 20, allowing the user to access the drum;

• a gasket, which is connected to the tub and which, during the operation of the laundry washing machine, washing drying machine or clothes dryer 1, adheres to the door 20 so as to prevent water or wash liquid from leaking out of the tub and

• interface means adapted to, among other things, allow the user to select at least one of the programmes and/or treatment parameters available in the laundry washing machine, washing/drying machine or clothes dryer 1 and/or to display useful information to the user.

An aperture is obtained in front face 4 to allow the user to access the drum in order to load laundry to be treated or to remove treated laundry. Door 20 is so shaped and positioned so as to, when closed, fully cover the aperture obtained in front face 4 and to prevent any water or wash liquid contained in the tub of the laundry washing machine, washing/drying machine or clothes dryer 1 from flowing out of the tub by leaking between front face 4 and door 20. In order to allow the user to open door 20, the latter is connected to front face 4 by means of one or more hinges (5 A and 5B in Fig.2), which allow door 20 to be rotated about an axis (usually a vertical axis). Advantageously, one may use the so-called "180 degree" hinges, which ensure a 180 degree rotation of door 20 without it interfering with surrounding elements. To allow door 20 to be latched with front face 4, on the side opposite to the hinges said door 20 has a catch (6 in Fig.2) which, by engaging into a suitable lock obtained on front face 4, ensures that door 20 cannot open during the operation of the laundry washing machine, washing/drying machine or clothes dryer 1. Besides, grip means 3 are associated with door 20 which allow the user to exert the force required to disengage the catch from the lock in order to open door 20. An important peculiarity of the machine of Fig.1 is its large door, i.e. door 20, for accessing the drum of the machine, which replaces the simple glass door bowl used in prior-art machines.

In its central area, door 20 has a window which allows the user to see inside the drum even when the door is closed. Door 20 is characterized by being substantially flat on the outside, i.e. its window has no substantial recess, unlike prior-art glass door bowls; however, this does not exclude the advantageous presence of a convex glass door bowls adjacent to the inner side of the door.

According to the present invention, door 20 comprises a plurality of thermoplastic components, at least two of which are locked together by welding. Typically, the total number of thermoplastic components is three or four; however, the present invention does not exclude that the total number may be just two or more than four, e.g. five or six.

Fig.2 illustrates, by way of explanatory but non-limiting example, a door 20 which represents a possible embodiment of the door for a household appliance, in particular for a front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer 1 being the subject of the present invention. In the above embodiment of the present invention, the welding technique used for connecting the thermoplastic components of door 20 is linear vibration welding. As a reminder, linear vibration welding utilizes, in order to weld together two thermoplastic parts, the heat generated by friction in the contact areas between the parts in the presence of a relative motion of a part with respect to another part. Usually, one part is clamped while the other part is gripped with a template and moved in a linear direction. The motion of the part gripped by the template takes place at a certain frequency, which is typically 100 Hz or 240 Hz, and at a certain amplitude, which is typically between 1.8 mm and 4.0 mm, if the frequency is 100 Hz, or between 0.7 mm and 1.8 mm, if the frequency is 240 Hz. Besides being put in relative motion, both parts are also pressed together, so that the heat generated by friction is increased by the pressure so exerted in the contact areas between the parts. Once the heat has melted an adequate quantity of thermoplastic material, the relative motion of the two parts is stopped and a weld bead is formed between the two parts, which are still kept under pressure, due to the solidification of the melted plastic material, resulting in the two parts becoming one piece. According to the embodiment of the invention illustrated in Fig.2, door 20 comprises three thermoplastic structural components: a rear element 8, a front element 9 and a central element 10.

The rear element 8 is used to support the other structural components of door 20, which are non-removably connected thereto by linear vibration welding. Rear element

8, shown in detail in Fig.3 and preferably made of ABS₅ is so shaped as to allow the other structural components of door 20 to be connected thereto. In particular, rear

^■ element 8 may comprise:

• a pair of seats 25A and 25B, adapted to house the pair of hinges 5A and 5B shown in Fig.2 and to allow door 20 to rotate about a vertical axis;

• a hole 26, allowing the catch 6, shown in Fig.2, to pass through it and lock door 20 after having engaged into the suitable lock being present in front face 4 of the laundry washing machine, washing/drying machine or clothes dryer 1 and

• a hole 22, adapted to house glass door bowl 12 shown in Fig.2, which hole is surrounded by an annular surface 29.

Glass door bowl 12 is preferably made of a transparent material such as glass, which, among other things, allows the user to see inside the household appliance even when door 20 is closed. Said glass door bowl 12 comprises:

• an annular surface 41, used to ensure the connection of glass door bowll2 to rear element 8 in that, when securing glass door bowl 12, said annular surface 41 comes in contact with the annular surface 29 of the rear element 8;

• a side surface 42, having substantially a shape of a cut cone , adapted to be housed in hole 22 of rear element 8 and

• a central surface 43, which may lie in a substantially vertical plane or, preferably, may comprise at least a portion somewhat inclined relative to the vertical axis.

Glass door bowl 12 is secured to rear element 8 by means of central element 10, preferably made of ABS. Central element 10 comprises surface 30 having the shape of a cut cone being essentially coaxial to hole 22 of rear element 8 and being so shaped as to have a diameter and an opening angle compatible with the diameter and inclination of side surface 42 of glass door bowl 12. Central element 10 is connected to rear element 8 through welding, preferably by linear vibration welding, glass door bowll2 being interposed between central element 10 and rear element 8. Rear element 8 and/or central element 10 may comprise:

• suitable reference means, adapted to ensure a correct positioning between central element 10 and rear element 8 before the welding process is carried out and/or

• suitable auxiliary means, comprising additional material used for forming the weld bead and additional material used for limiting the burrs generated during the welding process.

Fig.3 illustrates two explanatory but non-limiting examples of the above means on the rear element 8:

• reference means 27 A and 27B, essentially consisting of two monodimensional profiles, which at the same time simplify the positioning between central element 10 and rear element 8 and define the linear sliding direction of central element 10 along rear element 8 during the welding process (reference means 27A and 27B, as shown in Fig.3, are suitable for use when linear vibration welding is carried out with the vertical direction as a relative sliding direction between central element 10 and rear element 8) and

• auxiliary means 28, arranged near annular surface 29 and adapted to form, together with the corresponding material being present on central element 10, a weld bead ensuring a strong and water tight connection of glass door bowll2, thereby preventing adjacent water or wash liquid from leaking out.

Front element 9, preferably made of SAN or polycarbonate (or appropriately treated ABS), is the only component of door 20 which is visible when door 20 is closed; therefore, in addition to a structural function, it also has an aesthetic one. Said front element 9 comprises grip means 3, which allow the user of the front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer 1 to apply the force required for disengaging catch 6 from the lock in order to open door 20. According to a preferred embodiment of the present invention, grip means 3 are located in the upper portion of front element 9, thus making, the laundry washing machine, washing/drying machine or clothes dryer 1 more ergonomic, and soft elements are associated thereto in order to make the grip means more user friendly. Front element 9 is so designed as to allow the user to see inside the laundry washing machine, washing/drying machine or clothes dryer 1 when door 20 is closed: it follows that, since front element 9 has no hole matching glass door bowl 12, at least central portion 7 of front element 9 must be transparent. Front element 9 is connected to door 20 by welding, thereby non-removably coupling front element 9 with rear element 8, central element 10 and glass door bowll2 being interposed between front element 9 and rear element 8. As already stated above, this fastening may be carried out by using any known welding technique for thermoplastic materials. By way of explanatory but non-limiting example, front element 9 may be connected to rear element 8 by linear vibration welding. Rear element 8 and/or front element 9 may comprise suitable reference means and suitable auxiliary means similar to those already illustrated in the description of the connection between central element 10 and rear element 8.

It can be easily understood from this description how door 20, according to the present invention, overcomes the inherent drawbacks of the prior art. As a matter of fact, at the end of the welding process of its thermoplastic structural components, door 20 comprises just a single structural component. In fact, the welding creates continuity of material among the above-mentioned components, so that they become an enbloc structural component. It is clear that this considerably reduces the creaking sound typical of prior-art thermoplastic doors for household appliances: in fact, friction (as well as any consequent noise) is eliminated between the various thermoplastic components of door 20, for they have become as one piece. Furthermore, the welding used for manufacturing the door according to the invention allows to eliminate all removable connections, which would be subject to loosening during the life of the household appliance, resulting in door 20 having strength and solidity characteristics being essentially constant over time.

It should be noted that, according to an advantageous embodiment of the present invention, front element 9 of door 20 is made in one piece; this gives an impression of great strength of the door and of definite separation between the drum filled with liquid and the surrounding environment; however, it is appropriate to place also a glass door bowl, e.g. of the traditional type, behind the front element.

Advantageously, the whole front element 9 of door 20 is made of the same transparent material; on said element an opaque film is then applied, which has essentially a decorative function and is so shaped that the central area of front element 9 remains transparent. Conveniently, the opaque film is only applied onto the back surface of front element 9 (i.e. onto the surface facing the inside of the laundry washing machine, washing/drying machine or clothes dryer 1), so that the front surface of element 9 has a better appearance and is smooth and even to the touch.

If rear element 8 is sufficiently rigid and glass door bowl 12 is fastened to said element (e.g. by means of the central element 10), both the material and the shape of front element 9 can be chosen freely, thereby meeting a wider range of aesthetic and/or functional needs. Furthermore, if front element 9 is connected to the door, in particular to rear element 8, through welding, there will be no aesthetic and/or functional problems relating to the arrangement of screws and joints.

In the embodiment of the present invention described by way of non-limiting example with reference to Fig.2, rear element 8, central element 10 and front element 9 form, through linear vibration welding, a single thermoplastic element which ensures a permanent and solid fastening of glass door bowl 12 inside of it and which is connected to front face 4 of the front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer 1 through the pair of hinges 5 A and 5B. The present invention has been described with particular reference to the above embodiment, but it is clear that many changes may be made thereto by those skilled in the art. For example, if the glass door bowl is made of a thermoplastic material instead of glass, the door may be manufactured by using a different number and a different type of structural components. In this case, a possible embodiment of the present invention will consist of a door manufactured through welding a rear element including a central profile acting as a glass door bowl to a front element similar to front element 9 of Fig.2.

Advantageously, one may think of providing the door of a laundry washing machine, washing/drying machine or clothes dryer, in particular the machine being the subject of the present invention, with interface means adapted to, among other things, allow the user to select at least one treatment program and/or at least one treatment parameter available in the machine and/or to display useful information to the user. In this case, the interface means may advantageously be easily removable from the door, so that they can be repaired or replaced in the event of a failure preventing them from operating properly. In this regard, the interface means may be housed within a compartment (in the illustrated example, said compartment is designated by reference - numeral 23) obtained in the rear element of the door, and they may be secured to the door through removable connection means, such as screws and/or snap elements. The interface means must also be provided with a suitable power supply. To this end, a power cable supplying the interface means and any other data transfer cables may advantageously be routed from the inside of the door to the inside of the cabinet of the household appliance near or through one of the door hinges. It is apparent from the present description that, in order to make a door for a household appliance, in particular for a front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer, according to the present invention, it is necessary to adopt an innovative method, which is also a subject of the present invention. The general idea of said method is to make a household appliance door by carrying out at least one welding step between two thermoplastic components. According to a possible method for manufacturing a door for a household appliance, in particular for a front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer, which falls within the scope of the present invention, the door comprises a first, a second, a third and a fourth element, at least the first, the second and the third elements being made of a thermoplastic material, the first element comprising at least one hole and an annular surface surrounding said hole, and the fourth element comprising at least one annular surface; said method comprises the steps of: i) positioning the fourth element inside the hole of the first element, so that the annular surface of the fourth element comes in contact with the annular surface of the first element; ii) properly positioning the second element relative to the first element; iii) connecting the second element to the first element through welding, the fourth element being interposed between the second element and the first element; iv) positioning the third element relative to the first element properly, and v) connecting the third element to the first element through welding, the second element and the fourth element being interposed between the third element and the first element; According to an advantageous embodiment of the above method, the welding process used in step iii) is linear vibration welding, and the welding process used in step v) is linear vibration welding.

Referring to the previously described embodiment of door 20 illustrated in Fig.2, this method may be used to manufacture said door 20, wherein the first element is rear element 8, the second element is central element 10, the third element is front element 9 and the fourth element is glass door bowl 12.

The household appliance door and the related manufacturing method according to the present invention have been described with particular reference to a specific embodiment example, but it is clear that many changes may be made thereto by those skilled in the art without departing from the scope defined by the annexed claims.

Claims

1. Door (20) for a household appliance, in particular for a front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer (1), comprising a plurality of thermoplastic components, characterized in that at least two of said thermoplastic components are connected together through welding.

2. Door (20) according to claim 1, characterized in that said at least two thermoplastic components are' connected together through vibration welding.

3. Door (20) according to claim 2, characterized in that said at least two thermoplastic components are connected together through linear vibration welding.

4. Door (20) according to claim 1, characterized in that said at least two thermoplastic components are connected together through ultrasonic welding, or through hot seal, or through infrared welding, or through laser welding, or through spot welding.

5. Door (20) according to any of the previous claims, characterized in that at least one of said thermoplastic components comprises reference means adapted to obtain an adequate reciprocal positioning of said at least two thermoplastic components before the welding process is carried out.

6. Door (20) according to any of the previous claims, characterized in that at least one of said thermoplastic components comprises auxiliary means, said auxiliary means comprising additional material used for forming the weld bead and/or additional material used for limiting the burrs generated during the welding process.

7. Door (20) according to any of the previous claims, characterized in that said door (20) comprises a rear element (8), said rear element (8) being preferably made of ABS and said rear element (8) comprising a hole (22) surrounded by an annular surface (29).

8. Door (20) according to claim 7, characterized in that said door (20) also comprises a glass door bowl (12), said glass door bowl (12) being preferably made of glass and said glass door bowl (12) comprising an annular surface (41), said annular surface (41) of said glass door bowl (12) being in contact with said annular surface (29) of said rear element (8).

9. Door (20) according to claim 7 or 8, characterized in that said door (20) also comprises a central element (10), said central element (10) being preferably made of ABS and preferably comprising a surface (30) having the shape of a cut cone, said surface (30) having the shape of a cut cone being substantially coaxial to said hole (22) of said rear element (8).

10. Door (20) according to claim 9, characterized in that said central element (10) is connected to said rear element (8) through welding, said glass door bowl (12) being interposed between said central element (10) and said rear element (8).

11. Door (20) according to claim 7 or 8 or 9 or 10, characterized in that said door (20) also comprises a front element (9), said front element (9) being preferably made of SAN or polycarbonate and said front element (9) preferably comprising grip means

(3).

12. Door (20) according to claim 11, characterized in that said front element (9) is connected to said rear element (8) through welding, preferably through linear vibration welding.

13. Door (20) according to any of the previous claims, characterized in that said door (20) comprises interface means (2) adapted to allow the user to select at least one treatment programme and/or at least one treatment parameter and/or to display useful information to the user.

14. Door (20) according to any of the previous claims, characterized by comprising a compartment (23) for housing interface means (2), said compartment (23) being preferably obtained in a rear element (8) of the door (20).

15. Door (20) for a household appliance, in particular for a front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer (1), according to the innovative teachings of the present description and of the annexed drawings, which represent a preferred and advantageous embodiment of said door (20).

16. Laundry washing machine, washing/drying machine or clothes dryer (1), said laundry washing machine, washing/drying machine or clothes dryer (1) being of the front-loading or substantially front-loading type, characterized in that said laundry washing machine, washing/drying machine or clothes dryer (1) comprises a door (20) according to any of the previous claims.

17. Method for manufacturing a door (20) for a household appliance, in particular for a front-loading or substantially front-loading laundry washing machine, washing/drying machine or clothes dryer (1), characterized in that said method includes at least one welding step, preferably of the linear vibration type, between two thermoplastic components.

18. Method for manufacturing a door (20) according to claim 17, said door (20) comprising a first, a second, a third and a fourth elements, at least said first, second and third elements being made of a thermoplastic material, said first element comprising at least one hole and one annular surface surrounding said hole and said fourth element comprising at least one annular surface, said method comprising the steps of: i) positioning said fourth element inside said hole of said first element, so that said annular surface of said fourth element comes in contact with said annular surface of said first element; ii) properly positioning said second element relative to said first element; iii) connecting said second element to said first element through welding, said fourth element being interposed between said second element and said first element; iv) positioning said third element relative to said first element properly and v) connecting said third element to said first element through welding, said second element and said fourth element being interposed between said third element and said first element.

19. Method according to claim 18, wherein said welding carried out in said step iii) is a linear vibration welding and/or said welding carried out in said step v) is a linear vibration welding.