GB2099233A

GB2099233A - A suspension for the electric motor of a washing machine

Info

Publication number: GB2099233A
Application number: GB8214136A
Authority: GB
Original assignee: Philips Gloeilampenfabrieken NV
Current assignee: Koninklijke Philips NV
Priority date: 1981-05-19
Filing date: 1982-05-14
Publication date: 1982-12-01
Also published as: IT1136613B; IT8121800A0; ES512255A0; ES8305443A1; FR2506353A1; GB2099233B; DE3218238A1

Abstract

Washing machines comprise a tub 1 which supports a rotating drum into which the laundry to be washed is placed. The drum is rotated by an electric motor 5 by way of a belt transmission 2. The motor is supported by the tub by way of a substantially U-shaped support 15 welded to the tub. The motor is mounted in vibration- damping blocks 8, 9. These blocks are supported eccentrically in two housings 11, 12 supported by the support 15, one in a bore 14 in this latter and the other in a seat defined partly by the support itself and by a clamping stirrup 23 which, when slackened, enables the tension of the transmission belt to be adjusted. <IMAGE>

Description

SPECIFICATION A suspension for the electric motor of a washing machine The invention relates to a suspension for the electric motor of a washing machine, in particular a domestic washing machine, cmprising a drum mounted rotatably in a tub and driven by a belt transmission from said motor which is supported by said tub.

In washing machines of this type the electric motor, or rather the stator structure of this motor, comprises two aligned projections through which passes a pin supported in two supports fixed to the tub, and a third projection not aligned with the two preceding ones but in practice contained in the plane of one of them and through which there passes a bolt which also passes through an arcuate slot in a third support fixed to the tub and which locks together the projection and support by means of a nut and a split spring washer. In order to adjust the tension of the transmission belt, the bolt is slackened, the motor is rotated about said pin, and the bolt is tightened when the belt has been given the required tension.This three-point suspension method gives rise to vibrations which are not only noisy but which in the long term prove particularly damaging because they lead to fracture of the projections, in particular that through which the locking bolt passes. Because the projection in question forms part of the stator structure of the motor and is therefore not replaceable, the entire motor has to be replaced if the stated situation occurs. In addition to this serious drawback, there is the drawback that it is not easy to adjust the belt tension because it requires the use of tools which are not always available to the user.

The main object of the present invention is therefore to provide an electric motor suspension which is practically free from vibrations and therefore not subject to fracture, and which is easily adjustable and economically convenient.

The invention accordingly provides a suspension for the electric motor of a washing machine comprising a drum mounted rotatably in a tub and driven by a belt transmission from said motor which is supported by said tub, characterised in that the motor is supported at its ends in vibration-damping blocks mounted eccentrically in housings disposed in a support rigid with the tub.

According to an embodiment, one of the housings is mounted rotatably in a bore in the support, while the other is held in a seat defined partly by said support and by a clamping stirrup which can be slackened so as to be able to change the tension in the transmission belt by rotating the housings to consequently eccentrically displace the motor.

The clamping stirrup may comprise two strips, each of which can be hooked at one end to the support member and which can be connected together by means of screw means, which can be simply slackened by a screwdriver in order to enable the belt tension to be adjusted.

The features of the invention will be more apparent from the detailed description of an embodiment given hereinafter by way of non-limiting example with reference to the accompanying drawing, in which: Figure 1 is a front view of the suspension; and Figure2 is a section through Figure 1 on the line Il-Il.

In the figures, the reference numeral 1 indicates any known tub of a washing machine, not further shown. A normal drum is rotatably supported in the tub in any known manner, and is provided with a shaft which projects from the tub and on which a pulley is keyed. The shaft and pulley are not shown because they are of known type and do not form part of the invention. Said pulley is connected by a belt drive 2 to the drive pulley 3 keyed on to the shaft 4 of an electric motor 5.

The electric motor 5 comprises two aligned hubs or projections 6, 7 having a polygonal contour (for example hexagonal) as shown in Figure 1.

Vibration-damping blocks 8,9 of elastic material, for example rubber, are mounted on the hubs or projections 6, and have a bore of cross-section corresponding to that of the hubs in question. At one of their ends, the blocks 8,9 comprise an inner flange 10, which flanges abut the ends of hubs 6 and 7. When viewed in section, the outer contour of the blocks 8,9, visible in Figure 1, comprises in this example three portions forming part of the same circle and spaced apart by three equal circular arcs of smaller radius but having different centres.

These blocks 8 and 9 are received in seats of corresponding shape provided in respective annular housings 11, 12, moulded from plastics material, whose outer contour is substantially cylindrical with the geometrical axis A eccentric relative to the geometrical axis B of the blocks 11, 12, the hubs 6,7 and the motor shaft 4.

The housing 11 comprises a stop flange 13 at one of its ends. The housing 11 is mounted in a rimmed bore 14 present in an arm or side 21 of a sheet metal support member 15 welded to the lower side of the tub 1 and in the form of an inverted U with unequal arms 20,21.

The opposite housing 12 has a cylindrical contour and its geometrical axis A is eccentric to an equal extent relative to the longitudinal axis B of the motor, the relative hubs 6,7 and the block 9. The housing 12 comprises a peripheral slot 16 into which the semicircular edge 17 which downwardly limits the arm 20 of the support member 15 is inserted.

The arm 20 comprises two hook-like appendices 22, one on each of its two outer edges. A fixing stirrup 23 is hooked on to these appendices by means of suitable apertures (not shown), and is formed from two sheet metal strips 24, 25 which are arcuate over a certain portion to correspond approximately to the curvature of the housing 12, and are provided at one end with said hooking aperture and at the other end with bent portions 24A, 25A. The portion 25A is simply bored, whereas the portion 24A is bored and threaded. A tightening screw 26, utilising said bores, is used to tighten the housing 12 against the support 15. To facilitate registration of the clamping stirrup 23 against the housing 12 the latter can peripherally comprise a channel 27 able to receive portions of said stirrup.

When the tension in the belt 2 is to be adjusted, the screw 26 needs only to be slackened but without removing it. Then, by acting for example on the motor 5, the motor can be rotated about the geometrical axis A of the housings until the required tension is obtained. The screw 26 is then tightened.

Although only one embodiment of the invention has been described, it will be easy for an expert in the artto devices numerous modifications which must however all fall within the scope of the invention.

Thus for example the scope of the invention also includes a design in which the support member again has an inverted U configuration, but has equal arms analogous to the arm 20, so that in order to retain the motor in situ, two clamping stirrups 23 are used, one for each arm. In addition, the support member can be formed in one piece with the tub if of plastics construction.

Claims

1. A suspension for the electric motor of a washing machine comprising a drum mounted rotatably in a tub and driven by a belt transmission from said motor is supported by said tub, characterised in that the motor is supported at its ends in vibration-damping blocks mounted eccentrically in housings disposed in a support rigid with the tub.

2. A suspension as claimed in Claim 1, characterised in that one of the housings is mounted rotatably in a bore in the support, while the other is held in a seat defined partly by said support and by a clamping stirrup which can be slackened.

3. A suspension as claimed in Claim 2, characterised in that the stirrup comprises two strips, each of which can be hooked at one end to the support member and which can be connected together by means of screw means.

4. A suspension as claimed in Claim 1, characterised in that the motor ends by means of which the motor is supported in the vibration-damping blocks are torsionally rigid with these latter.

5. A suspension as claimed in Claim 1, characterised in that the vibration-damping blocks are torsionally rigid with the relative housings.

6. A suspension as claimed in Claim 1, characterised in that the support is of inverted U configuration with unequal arms, one comprising a bore for containing one housing and the other comprising a concave recess for receiving a portion of the perimeter of the other housing.

7. A suspension as claimed in Claim 1, characterised in that the support is of inverted U configuration with substantially equal arms comprising concave recesses for receiving a portion of the perimeter of the housings, each being retained by a clamping stirrup.

8. A suspension as claimed in any preceding Claim, characterised in that the support is formed in one piece with the tub and the latter is of plastics construction.

9. A suspension for the electric motor of a washing machine substantially as herein described with reference to the accompanying drawing.