GB2454092A

GB2454092A - Detector unit for a washing machine

Info

Publication number: GB2454092A
Application number: GB0819481A
Authority: GB
Inventors: Paolo Da Pont; Ugo Gaino
Original assignee: Elbi International SpA
Current assignee: Elbi International SpA
Priority date: 2007-10-24
Filing date: 2008-10-23
Publication date: 2009-04-29
Anticipated expiration: 2028-10-23
Also published as: GB0819481D0; ITTO20070135U1; GB2454092B; DE202008014153U1

Abstract

A washing machine is provided with detector unit 7, which comprises a magnetic element 24 and a housing 8, one of which may be connected to the machine structure 2, the other being connected to the laundry drum. The housing comprises two separate transducers 15, 21 which may be coils or windings. The first transducer 15 is associated with a movable magnetic core 14 to provide electrical signals based on the level of the fluid within the laundry drum. The second transducer 21 is associated with the magnetic element 24 to provide electrical signals based on the weight of the load within the laundry drum. The housing also contains an electronic processing device 19 to process signals supplied from the transducers. The two transducers may be inclined relative to one another. The magnetic element may be connected to the structure by a number of articulated joints 26, 28.

Description

WASHING MACHINES

The present invention relates to washing machines.

More specifically, the invention relates to a washing machine comprising a support structure in which a washing chamber containing a rotatably-mounted laundry drum is suspended, and in which detector means are provided for supplying electrical signals indicative of the level of the washing bath in the chamber as well as electrical signals indicative of the weight of the load contained in the laundry drum, the detector means comprising a magnetic element and an associated detection unit of which one is connected to the structure of the machine and the other to the washing chamber so that their relative positions depend on the position of the washing chamber relative to the structure.

A washing machine of this type is described, for example, in the Applicant's German patcnt application DE 102006020151 Al.

In the washing machine described in this prior document, the detector means comprise, for indicating the washing bath level as well the weight of the load contained in the laundry drum, a single coil cooperating with two different cores which can bring about variations in the inductance of the coil upon variations of the bath level and upon variation of the load, respectively.

This solution may present problems connected with the different sensitivity that is required to detect the variations in inductance connected with the variation in the bath level in comparison with the variations in inductance due to the weight of the load contained in the drum.

An object of the present invention is to propose a washing machine of the type defined above which has improved characteristics with respect to the detection of the variations in the washing bath level and in the weight of the load contained in the drum, respectively.

This and other objects are achieved, according to the invention, by a washing machine the main characteristics of which are defined in the appended claim.

Further characteristics of the washing machine according to the invention are defined in the subordinate claims.

Further characteristics and advantages of the invention will become clear from the following detailed description which is given purely by way of non-limiting example with reference to the appended drawings, in which: Figure 1 is a partial schematic view of a washing machine according to the present invention, and Figure 2 is a partially-sectioned, partial view which shows an embodiment of a detection unit included in a machine according to the invention.

With reference to the drawings, a washing machine, generally indicated 1 in Figure 1, comprises, in known manner, a support structure 2 inside which a substantially cylindrical washing chamber 3 is suspended.

A laundry drum 4 is mounted rotatably in the chamber 3 and is rotated in operation in known manner, for example, by means of an electric motor, not shown.

The machine 1 may be of the front loading or top loading type.

In known manner and as shown schematically in Figure 1, the assembly formed by the washing chamber 3 and by the laundry drum 4 is suspended in the support structure 2 of the machine by resilient devices, for example, springs, which are represented symbolically in the diagram of Figure 1 by a spring, indicated 5, and associated damping devices including one or more shock-absorbers such as that indicated 6 in Figure 1.

A detection device mounted in the machine I is generally indicated 7 in the drawings. As will be explained further below, the detector device 7 is intended to supply electrical signals indicative of the level of the washing bath in the chamber 3 as well as electrical signals indicative of the weight of the load contained in the laundry drum 4.

In the embodiment illustrated by way of example, the detector device comprises a single support housing 8 formed by a lower body 9 and by an upper body 10 which are firmly connected to one another. The housing 8 is fixed to the wahing chamber 3, for example, in the manner shown schematically in Figure 1.

With reference to Figure 2, a resilient diaphragm 12 is mounted movably in the lower body 9 of the housing 8 and defines, relative to the body 9, a chamber 13 of variable volume. A core 14 of ferromagnetic material, for example, of ferrite, is associated with the central portion of the diaphragm 12 in known manner. The core 14 is mounted so as to be movable axially inside a winding or coil 15 which is mounted in a fixed position inside the body 9. A spring 16 acts on the core 14 urging it downwards.

The lower body 9 has an inlet connector or mouth 9a which is connected, by means of a small flexible pipe 16 (Figure 1), to a so- called air trap 17 associated with the washing chamber 3.

The arrangement is such that, when the level of the bath in the washing chamber 3 reaches or exceeds a predetermined level, the pressure of the air contained between the air trap 17 and the chamber 13 of the detector device 7 increases, bringing about a change in the position of the core 14 relative to the associated coil 15 and a consequent change in the inductance of the coil. The coil is connected to electronic processing circuits which are carried by a support plate (indicated 19 in Figure 2) housed inside the support housing 8 and can be connected, by means of a connector 20 (Figures 1 arid 2) formed in the housing 8, to an electronic unit ECU for controlling the operation of the machine 1 (Figure 1).

The upper body 10 of the housing 8 of the detector device 7 has a hollow lower portion I Oa which is connected at the top to a tubular guide portion I Ob. The hollow portion 1 Oa of the body 10 houses a second winding or coil 21 carried by shaped, approximately tubular reel 22.

A rod 23 extends in the upper portion lOb of the body 10 and carries, at its lower end, a core 24 of ferromagnetic material, for example, ferrite.

The core 24 extends operatively in the portion IOa of the body 10 in the vicinity of the coil 21 (although in Figure 2 it is shown removed from the body 10 of the support housing 8).

The upper end of the rod 23 is connected to a connecting rod 25 by means of a first ball-and-socket joint 26. The connecting rod 25 is in turn connected to an anchoring element 27 by means of a second ball-and-socket joint 28. The element 27 is anchored on the load-bearing structure 2 of the washing machine 1.

The above-described detector device 7 operates substantially as follows.

When the user puts laundry to be washed in the drum 4 of the machine, the assembly formed by the washing chamber 3 and by the drum 4 drops under the effect of the load to an extent which depends on the weight of the load.

The relative positions of the rod 23 and the support housing 8, that is, the position of the core 24 relative to the associated coil 21, vary correspondingly. The coil 21 is advantageously also connected to the electronic circuitry carried by the plate 19 (Figure 2) which, as stated above, is connected to the control unit ECU of the machine.

The change in the position of the assembly formed by the washing chamber and by the drum 4 under the effect of the load placed in the drum is thus translated into a change in the inductance of the winding or coil 21 which is processed by the circuits carried by the plate 19 and detected and interpreted by the unit ECU as indicative of the weight of the laundry loaded into the drum 4.

Subsequently, when the washing bath (water, detergent, etc.) is admitted to the washing chamber 3, and hence in a condition in which the load is constant, the change in the inductance of the winding or coil 15 detected by the ECU is indicative of the change in the level of the washing bath.

In the embodiment illustrated by way of example, the rod 23 and the associated unit 8 are fixed to the structure 2 of the machine and to the washing chamber 3, respectively.

Naturally, a reversed arrangement, that is, an embodiment in which the rod 23 and the associated core 24 are connected to the washing chamber 3 and the support housing 8 is connected to the load-bearing structure 2 of the machine falls within the scope of the invention.

In the embodiment which is shown in the drawings and described above, the portion relating to the detection of the washing bath level and the portion relating to the detection of the load weight are arranged substantially coaxially with the axes of relative movement between the cores and the associated coils substantially coinciding.

In a variant, not shown, the portion relating to the detection of the washing bath level may be oriented along a axis of relative movement which is inclined at a predetermined angle (for example 900) to the axis of relative movement of the portion of the device that is intended to detect the load weight. In this case, the electronic processing devices to which the coils 15 and 21 are connected may advantageously be arranged to derive, from the changes in the inductances of the coils, electrical signals that are indicative of the disequilibrium of the drum 4 along two different axes, in particular along the vertical axis and a horizontal axis. By the further addition of a further coil and of an associated movable core which are oriented in a manner such that their axis of relative movement is inclined to those of the above-described cores and coils, it is possible also to derive information relating to the spatial position of the assembly formed by the washing chamber 3 and by the drum 4 relative to the load-bearing structure 2 of the washing machine 1.

In embodiments which are not shown but which fall within the scope of the invention, other sensors of known type, for example Hall-effect sensors, may be used as transducer elements instead of coils.

The electronic circuitry carried by the support plate 19 may be arranged to perform a calibration of the washing bath level and drum load transduction characteristics.

Naturally, the principle of the invention remaining the same, the forms of embodiment and details of construction may be varied widely with respect to those described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the invention as defined in the appended claims.

Claims

1. A washing machine (I) comprising a support structure (2) in which a washing chamber (3) containing a rotatably-mounted laundry drum (4) is suspended, and in which detector means (7) are provided for supplying electrical signals indicative of the level of the washing bath in the chamber (3) as well as electrical signals indicative of the weight of the load contained in the laundry drum (4), the detector means (7) comprising a magnetic element (24) and an associated detection unit (8) of which one is connected to the structure (2) of the machine (1) and the other to the washing chamber (3) so that their relative positions depend on the position of the washing chamber (3) relative to the structure (2), the detection unit (8) comprising: a single support housing (8) in which there are mounted: a sensor device (12-16) including a movable magnetic core (14) the position of which relative to the housing (8) is variable according to the level of the washing bath in the chamber (3), and an associated first transducer (15) which is connected to the housing (8) and can provide signals indicative of the relative position of the core (14), a second transducer (21) which is distinct and separate from the first (15) but is also connected to the housing (8) and can provide electrical signals indicative of the position of the magnetic element (24) relative to the housing (8) of the detection unit, and electronic signal processing means (19) which are provided in the housing (8), are connected to the first transducer (15) and to the second transducer (21), and are arranged to process the signals supplied thereby, in accordance with predetermined procedures.

2. A washing machine according to Claim I in which the first and second transducers comprise respective coils or windings (15, 21) the inductances of which are variable, in operation, according to the relative positions of the associated cores or magnetic elements (14, 24).

3. A washing machine according to Claim 1 or Claim 2 in which the first transducer (15) and the associated core (14) are oriented along an axis of relative movement which is inclined at a predetermined angle to the axis of relative movement of the second transducer (21) and of the associate magnetic element (24), and in which electronic processing means (19; ECU) are connected to the transducers (15, 21) and are arranged to produce electrical signals that are indicative, in operation, of the disequilibrium of the drum (4) and of the respective load along two different axes, preferably vertical and horizontal axes.

4. A washing machine according to any one of the preceding claims in which the magnetic element (24) is carried by a rod (23) which is connected to the structure (2) of the machine (1) by means of at least one movable member (25) and associated articulated joints (26, 28), preferably ball-and-socket joints.

5. A washing machine substantially as herein described with reference to and as illustrated in the accompanying drawings.