Domestic appliance comprising an actuator

Abstract

A domestic appliance, such as a steam iron or a coffee making apparatus comprises a housing, a water reservoir, an actuator, and a boiler for providing hot water or steam for use by the appliance. In operation, a plunger pump of the actuator is reciprocating at the mains frequency, which introduces vibrations. To reduce undesired sound and noise from the vibrations, the domestic appliance further comprises a sub frame and a base frame, wherein the actuator is mounted on the sub frame and a resilient member is arranged between the sub frame and the base frame for moveably mounting the sub frame at the base frame.

Claims

1. A domestic appliance comprising: a base frame; an actuator provided with a drive member and arranged for reciprocating movement of the drive member; a rigid sub frame, wherein the actuator is mounted on the rigid sub frame; and a resilient member that comprises at least one elastomer mount arranged between the rigid sub frame and the base frame for moveably mounting the rigid sub frame at the base frame, wherein an interior portion of the at least one elastomer mount is constructed and arranged to allow both (i) deflection in an x,y direction for lateral movement of the rigid sub frame in a plane parallel to the base frame and (ii) rotation in a plane of the rigid sub frame for rotation of the rigid sub frame around an axis of rotation transverse to the plane of the base frame, wherein the at least one elastomer mount further comprises a disc shaped elastomer mount and the interior portion comprises the disc shaped elastomer mount with a portion of material removed from an interior of the disc shaped elastomer mount of a length L, between a first point of the elastomer mount where the elastomer mount rests on the base frame and a second point of the elastomer mount where on the rigid sub frame rests, and in which a distance d along a horizontal cross-section, between a side of the elastomer mount and the base frame, is sufficiently large, together with length L, allows both (i) the deflection of the disc shaped elastomer mount in the x,y direction and (ii) the rotation of the disc shaped elastomer mount in the plane of the rigid sub frame.

2. The domestic appliance according to claim 1, wherein the axis of rotation is through a center of gravity of a mass and shape of the rigid sub frame and the actuator.

3. The domestic appliance according to claim 1, wherein the domestic appliance further comprises a boiler or a flow-through heater for water heating or steam generation mounted at the rigid sub frame.

4. The domestic appliance according to claim 3, wherein the actuator is operationally connected to the boiler or the flow-through heater via a pressure resistant tube.

5. The domestic appliance according to claim 1, wherein the domestic appliance further comprises a water reservoir provided at the rigid sub frame, the water reservoir being in fluid communication with the actuator via a flexible tube.

6. The domestic appliance according to claim 5, wherein the water reservoir is detachably mounted to the rigid sub frame.

7. The domestic appliance according to 7, wherein the flexible tube comprises a corrugated tube.

8. The domestic appliance according to claim 1, wherein the actuator comprises a plunger pump or a diaphragm pump.

9. The domestic appliance according to claim 1, wherein the disc shaped elastomer mount is adapted to be mounted via a connecting member in a center of the disc shaped elastomer mount to the base frame, and further wherein the length L determines a maximum swing of the interior portion and a horizontal movement related to the swing of the sub frame with respect to the base frame.

10. The domestic appliance according to claim 9, further wherein the disc shaped elastomer mount is further provided with a cap overlying a portion of the disc shaped elastomer mount, wherein the cap is adapted to prevent the connecting member from pushing through the disc shaped elastomer mount due to forces exerted on the disc shaped elastomer mount.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic illustration of a steam iron;

(2) FIG. 2 shows a schematic illustration of an arrangement of the elastomer mounts on the sub frame of the steam iron;

(3) FIG. 3 shows a schematic illustration of a cross-section of an elastomer mount for the steam iron;

(4) FIG. 4 shows a schematic illustration of a coffee making apparatus; and

(5) FIG. 5 shows a schematic illustration of an elastomer mount for a coffee making apparatus.

DETAILED DESCRIPTION OF EMBODIMENTS

(6) In the figures like numbers refer to similar components.

(7) FIG. 1 shows a steam iron comprising a base frame, for example a housing 3, an actuator and a rigid sub frame 7. The actuator may be a plunger pump 5 connected to the housing 3 via the rigid sub frame 7. The rigid sub frame 7 can be a rectangular steel plate or enforced plastic plate. The steam iron 1 may be provided with a water reservoir 9 detachably mounted at the housing 3. An outlet of the water reservoir 9 is connected to an inlet of the plunger pump 5 via a flexible tube or corrugated tube 11. Furthermore, the steam iron 1 may comprise a boiler 13 for heating water or generating of steam. An inlet of the boiler 13 is connected to an outlet of the plunger pump 5 via a high pressure resistant tube 15. An outlet of the boiler 13 is connected to an iron 19 via a further high pressure tube 17 for providing steam to the iron 19. The plunger pump 5 comprises a solenoid 8 and a plunger 6 cooperating with the solenoid. In operation, the plunger pump 5 is usually reciprocating at the mains frequency, for example 50 or 60 Hz.

(8) The steam iron 1 further comprises a resilient member, for example elastomer mounts, 21,23, 25,27 whereby the plunger pump 5 is mounted on the sub frame 7 and the sub frame 7 is moveably mounted at the housing 3 via the elastomer mounts 21,23,25,27. The elastomer mounts 21,23,25,27 allow a lateral movement and/or a rotation of the subframe around an axis perpendicular to the sub frame 7.

(9) FIG. 2 shows a cross section of the sub frame 7 and the arrangement of the elastomer mounts 21, 25, 23,27. The four elastomer mounts 21, 25, 23,27 are positioned at the respective corners of the rigid sub frame 7.

(10) FIG. 3 shows a detailed cross-section of one of the elastomer mounts 21,23,25 and 27. The elastomer mount 21 can be disc shaped and is mounted via a connecting member, for example, a screw 29 in the center of the mount 21 to the base frame 7. The elastomer mount 21 is provided with a cap 31 to prevent that the screw 29 is pushed through the elastomer mount 21 due to large forces on the elastomer mount 21, for example during shock tests. The cap may be made of a polymer.

(11) The material of the elastomer mounts 21,23,25 and 27 may comprise a synthetic material like Ethylene Propylene Diene Monomer (EPDM) or Nitrile Polymer Rubber (NPR) of mid-range hardness (50-50 Sh-A).

(12) A part of the synthetic material may be removed from the interior of the disc 21 to allow sufficient deflection in an x, y direction or a rotation in the plane of the sub frame 7.

(13) The sub frame 7 of the steam iron rests on a portion 35 of the elastomer mount 21. The length L of the portion 35 of the elastomer mount 21 between a point where on the elastomer mount 21 rests on the housing 3 and a point of the elastomer mount whereon the sub frame 7 rests, determines a maximum swing of this portion and a horizontal movement related to this swing of the sub frame 7 within the housing 3. The distance d along a horizontal cross-section between a side of the elastomer mount 21 and the housing 3 should be sufficiently large to allow the horizontal movement of the sub frame 7 within the housing 3 without bouncing to the housing. In an embodiment the length L is 1 cm and the distance d is 1 mm.

(14) In this arrangement the transmission of the vibrations from the reciprocating plunger pump 5 to the housing 3 are substantially reduced and hence structure born noise induced by the housing 3 is reduced.

(15) By increasing the mass of the sub frame 7 by mounting the water reservoir 9 and the boiler 13, the sub frame acceleration is reduced and the transmitted vibrations to the housing are reduced. The system of sub frame and elastomer mounts can be further modeled as the strings in a pendulum system. The natural frequency fn of such pendulum system can then be given by
n=1/(2L/g)
wherein L represents the length of the portion 35 of the elastomer mount 21 between a point where on the elastomer mount 21 rests on the frame 3 and a point of the elastomer mount whereon the sub frame 7 rests, and
g represents the gravitation constant.

(16) Furthermore, the boiler 13 for water heating or steam generation is mounted at the sub frame 7. The advantage of this arrangement is that the mass of the boiler 13 adds to the mass of the sub frame 7. By adding more weight to the sub frame 7 the acceleration of the sub frame 7 induced by the reciprocating plunger will be smaller and the transmission force on the housing will be reduced.

(17) A further advantage of this arrangement is that ideally the boiler 13 and the plunger vibrations are identical in amplitude and phase, and the high pressure tube 15 connected from the outlet of the plunger pump 5 to the boiler 13 is stationary with respect to the boiler 13 and the pump 5, resulting in less wear in the high pressure tube 15, which wear may lead to leakage of the tube. Furthermore, in this arrangement the stationary high pressure tube 15 is exposed to less vibration and radiates less noise.

(18) In an embodiment the mass and shape of the plunger pump 5, the boiler 13 and the sub frame 7 may be dimensioned and arranged at the sub frame 7 such that the center of gravity is coincident with the crossing of a vertical axis of rotation and the sub frame the dynamic load on the subframe is then symmetrically with respect to the elastomer mounts 21,23,25 and 27.

(19) FIG. 4 shows a coffee making apparatus 40 comprising a base frame, for example, a housing 41, an actuator and a rigid sub frame 7. The actuator may comprise a plunger pump 5 connected to the housing 41 via the rigid sub frame 7. The coffee making apparatus 40 may be provided with a water reservoir 9 detachably mounted in the housing 41, an outlet of the water reservoir 9 is connected to an inlet of the plunger pump 5 via a low pressure tube or corrugated tube 11. Furthermore, the coffee making apparatus 40 comprises a boiler 13 for heating water. The boiler 13 is mounted on the rigid sub frame 7. An inlet of the boiler 13 is connected to an outlet of the plunger pump 5 via a high pressure resistant tube 15. An outlet of the boiler 13 is connected to a coffee pad holder 44 via a tube 42 for dispensing hot water. In operation, the plunger pump 5 is usually reciprocating at the mains frequency, for example 50 or 60 Hz.

(20) The coffee making apparatus 40 further comprises a resilient member, for example, an elastomer mount 46 for reducing transmission of vibrations from the plunger pump 5 to the housing 41. The plunger pump 5 is mounted on the sub frame 7 and the sub frame 7 is moveably mounted at a rod in the housing 41 via the elastomer mount 46. The elastomer mount 46 can be arranged in the center of the sub frame 7. The elastomer mount 46 allow a lateral movement and/or a rotation of the subframe around an axis perpendicular to the sub frame 7.

(21) Dimensioning of the elastomer mount 46 and the sub frame 7 for reduction of transmission of vibrations of a reciprocating plunger 8 to the housing 41 via the sub frame 7 is explained above in relation with the embodiment described in relation with FIG. 2.

(22) FIG. 5 shows a cross section of the elastomer mount 46 for use in the coffemaking apparatus 40. The elastomer mount 46 is connected to the housing via a cap 43 and a screw 44. The elastomer mount 46 may comprise a synthetic material like Ethylene Propylene Diene Monomer (EPDM) or Nitrile Polymer Rubber (NPR) of mid-range hardness (50-50 Sh-A).

(23) In the above described embodiments of the steam iron 1 and the coffee making apparatus 40 the plunger pump 5 may be replaced by a diaphragm pump.

(24) Although illustrative embodiments of the present invention have been described with reference to the accompanying drawings, it is to be understood that the invention is not limited to these embodiments. Various changes or modifications may be effected by one skilled in the art without departing from the scope or the spirit of the invention as defined in the claims. Accordingly, reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases in one embodiment or in an embodiment in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, it is noted that the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.