HK1155893B - Controlled door opening in domestic appliances - Google Patents

Abstract

A door opening mechanism for a domestic appliance (for example, a microwave oven), the domestic appliance including a housing, a front door, and a resilient member (e.g. spring bias), for urging the door open, wherein the door opening mechanism is adapted to be located within the housing; the door opening mechanism comprising: a retention mechanism, engageable with the door and movable between a first configuration, in which the door is retained in a closed position, and a second configuration, in which the door is non-engaged; a cam, the cam having a plurality of cam surfaces, each being adapted to move the retention mechanism out of said first configuration through camming action; and a rotary motor, for driving the cam in response to control signals. The cam suitably comprises a plurality of equally angularly spaced projections, the outer surfaces of the cam between successive projections comprising a cam surface. Suitably, each cam surface comprises of two slopes, one for clockwise cam motion and the other for anticlockwise cam motion, both cooperating with the retention mechanism as it moves from the first configuration to the second configuration, thus opening the door. This allows for a directional or multi-directional camming action. Each cam surface may comprise a first part, for cooperating with the retention mechanism as it moves into the first configuration, and a second part, for cooperating with the retention mechanism as it moves from the first configuration to the second configuration. In use, the cam moves a rotatable member into a position such that the spring biasing element acts on the door such that the door rotates to the partially open position. The rotatable member has a guide surface, the guide surface including a transition point and being disposed such that, in use, a key member attached to the door is capable of sliding contact with the rotatable member along the guide surface; wherein, after the key member has slid beyond the transition point, forces due to gravity and to the spring biasing element operate on the door such that the door rotates to the partially open position. Also disclosed is a domestic appliance, comprising: a housing, a front door, the door opening mechanism, a resilient member (e.g. spring bias), for urging the door open, and controller, coupled to the motor, the controller being operable in response to one or more signals to activate the motor, and thereby cause the door to move open.

Description

Controlled opening door for household appliances

Technical Field

The present invention relates to domestic appliances and more particularly to a controlled door opening mechanism for such domestic appliances.

Background

The present invention relates to domestic appliances with hinged doors, such as ovens, freezers and the like. The invention is particularly advantageously associated with microwave ovens, for example. However, the invention is applicable to electrical domestic appliances, whether stand-alone or adapted for built-in mounting, i.e. in a frame or housing, or in a kitchen or other furniture (sometimes known as "built-in" or "built-in" appliances).

Traditionally, microwave ovens and other electrical household appliances having doors employ a purely mechanical (e.g., latching) opening mechanism for the door. For example, published UK patent application GB2410059A discloses an electrical domestic appliance, such as a refrigerator or microwave oven, having a door hinged laterally between a lower supporting hinge and an upper hinge. The upper hinge includes an inclined bracket having a protruding portion, and the upper edge of the door is provided with a slider in the shape of a ramp, which gradually acts with the protruding portion when the door is opened to an angle greater than a predetermined value (e.g., 130 degrees and 140 degrees), applying a gradually increasing resistive torque as the opening angle increases.

The problems of the conventional appliances are: typically, the user must exert a significant force on a lever, handle or button to mechanically release the latch or door lock to open the door; thus, for example, use may be problematic or unsatisfactory for disabled and infirm people. In addition, for these users and for the health of the individual, this prior art mechanism requires that the user be physically located at the device in order to apply the force to open the door. Also, from an aesthetic point of view, a handle or large mechanical button for opening the door may be considered aesthetically unpleasing.

Another problem particularly with microwave ovens is that the mechanism does not support automatic (or remote controlled) opening of the door immediately after cooking is complete (i.e. application of microwave energy is stopped) or for a relatively short time. For example, it may not be desirable to have a hot (usually steamed) food item stay in a microwave with the door closed, and it may be desirable to have the food item or meal stay in "open space" for a while before a meal.

Disclosure of Invention

The present invention provides a door opening mechanism for a domestic appliance comprising a housing, a front door and a resilient member for forcing the door open, wherein the door opening mechanism is locatable within the housing; the door opening mechanism includes: a retention mechanism engageable with the door and movable between a first configuration in which the door is retained in the closed position and a second configuration in which the door is not engaged; a cam having a plurality of cam surfaces, each cam surface being capable of moving the retention mechanism away from the first configuration via a camming action; and a rotation motor for driving the cam in response to the control signal.

Preferably, the cam includes a plurality of equally angularly spaced projections, and the outer surface of the cam between adjacent projections includes a cam surface. Preferably, each cam surface comprises two ramps, one for clockwise cam movement and the other for anticlockwise cam movement, the two ramps interacting with the retention mechanism as it moves from the first configuration to the second configuration, thereby causing the door to open. Preferably, each protrusion forms a transition point between the first configuration and the second configuration.

Alternatively or additionally, each cam surface includes a first portion for cooperating with the retention mechanism when the retention mechanism is moved to the first configuration, and a second portion for cooperating with the retention mechanism when the retention mechanism is moved from the first configuration to the second configuration. Alternatively or additionally, each projection forms a transition point between a first portion of one cam surface and a second portion of an adjacent cam surface.

The mechanism may be (i) operable in a clockwise and counterclockwise camming motion, (ii) only clockwise camming, or (iii) only counterclockwise camming. The cam may have 1-10 cam surfaces, more preferably 3-5 cam surfaces, and more preferably 4 cam surfaces.

Preferably, the resilient member comprises a first spring biasing element, such as a coil spring.

Preferably, the holding mechanism comprises: a rotatable member which is rotated by the cam whilst the motor is actuated in use; and a second spring biasing element; wherein in use, the second spring biasing element acts to urge the retention mechanism into the first configuration during at least a portion of its movement between the first and second configurations. Preferably, the rotatable member comprises an engagement surface for sliding engagement with a cam surface on the cam in use.

Preferably, the rotatable member has a guide surface comprising a transition point and configured such that, in use, a key member attached to the door is able to be in sliding contact with the rotatable member along the guide surface; wherein after the key member slides beyond the transition point, gravity and the force caused by the spring biasing element operate on the door such that the door rotates to the partially open position.

According to another aspect of the present invention, there is provided a household appliance comprising: a housing; a front door; a resilient member for urging the door open; the door opening mechanism according to any one of claims 1 to 8 of the appended claims; and a controller connected to the motor, the controller operable in response to one or more signals to actuate the motor and thereby cause the door to move open.

Preferably, the resilient member comprises a first spring biasing element, such as a coil spring.

The appliance also preferably includes a microswitch positioned to be engaged by adjacent tabs and to be in a closed state when the retention mechanism is in the first configuration.

In one embodiment, the controller is operable in a switch actuation mode; the shell is provided with an electric switch, such as a touch switch, which is connected to the controller and can be operated by a user; and the controller is operable, in use, to actuate the actuator when the detection signal from the electrical switch is high.

In another embodiment, the controller is alternatively or additionally operable in a remote actuation mode; a wireless receiver unit, such as an Infrared (IR) receiver, is provided on the housing that is connected to the controller and is operable by a user remote unit, such as an IR remote controller; and the controller is operable, in use, to actuate the actuator when the detection signal from the wireless receiver unit is high.

In another embodiment, the controller is alternatively or additionally operable in an auto-open mode, the housing providing a user selection interface, such as buttons and/or dials and a display, connected to the controller and operable by a user, the user selection interface including an auto-open setting selectable by the user in use; the controller is connected to receive input signals (high, low) indicating whether electrical operations (e.g. cooking operations) in the appliance are on or off, respectively; and the controller is operable, in use, to actuate the actuator when the received signal is low.

In another embodiment, the appliance is capable of temporary electrical operation, wherein: the controller may alternatively or additionally be capable of operating in a delayed auto-on mode; the controller is connected to the storage device to store the time period; the controller is connected to receive input signals (high, low) indicating whether electrical operations (e.g. cooking operations) in the appliance are on or off, respectively; and the controller is operable, in use, to actuate the actuator when the controller determines that (a) the received signal is low and (b) the time period has elapsed.

The user selection interface may include a delayed auto-on setting that can be selected by the user when in use; wherein the user selection interface is operable by a user to input the time period before storage in the storage device. The time period may be about (a)1-20 seconds, (b) up to 1 minute, or (c)1-5 minutes.

Alternatively, rather than being operable in response to a high detected or received signal, the controller may be operable to make any predetermined detectable change in the state or voltage level of the detected or received signal in response to (a) the detected or received signal being low, or (b) vice versa, or (c) the detected or received signal.

The motor is operable in both clockwise and counterclockwise directions, thereby moving the retaining mechanism in either direction. Alternatively, a motor capable of operating in only one direction (e.g., only clockwise) may be used to move the retaining mechanism away from the position.

The appliance may be (a) an oven and the temporary electrical operation is cooking by any combination of microwave, baking, convection or steaming, or the appliance may be (b) a bread maker, yogurt maker or similar machine and the temporary electrical operation is electrical warming or heating.

With the technique according to the invention, appliances such as microwave ovens can be opened with very little manual force from the user, for example via a touch switch or a remote control, which is beneficial to the infirm.

The invention enables the appliance to be automatically opened, for example at the end of electric (microwave, baking, convection) cooking. This may reduce the amount of moisture accumulated inside the oven due to the steam.

The present invention allows the appliance to be designed without a handle and large mechanical buttons. This makes cleaning easier and is valuable from an aesthetic standpoint, where the handle may be considered aesthetically unappealing, or where it is desirable to have a "flat" design on the front surface of the appliance that is visible. This also means that the invention is applicable to stand-alone or built-in appliances.

Another feature is that the present invention has an opening device, which is different from the locking device, so that the user can replace the opening mechanism for manual operation and actually open the door at any time by pulling, thus overcoming the problems associated with power failure. The invention allows the user to see the response immediately when pressing the door release button: the door opening mechanism is acting and the user will start to see the door open. On the other hand, if a delay is desired (e.g., built-in "standby time" as part of the cooking program), they can be easily integrated into the controller software. Since the opening mechanism can be operated with a rotation motor capable of rotating in clockwise and counterclockwise directions, only in clockwise directions, and only in counterclockwise directions, various motors can be used; including most types of AC and DC motors.

Drawings

Embodiments of the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which:

fig. 1 shows (a) a front view and (b) a plan view of a home appliance (microwave oven) according to an embodiment of the present invention after a door is opened;

fig. 2 illustrates a portion of an electrical system of the microwave oven of fig. 1; and

fig. 3 illustrates a partial internal view of the microwave oven of fig. 1, showing a door opening mechanism and its operation, in which (a) the general configuration of the key member, (b) the door is in a closed position, (c) the half-stroke position, and (d) the door is in an open position, according to an embodiment of the present invention.

In the description and drawings, like reference numerals are used to refer to like elements.

Detailed Description

Fig. 1 shows (a) a front view and (b) a top view of a household appliance (microwave oven) incorporating a door opening mechanism according to an embodiment of the present invention after the door is opened. Referring to fig. 1(a), a door 102 of a microwave oven is shown, along with a control panel 104 on the right hand side. The door 102 is hinged at the left side 106 as is conventional (although the invention is also applicable to doors hinged at the right hand side, top or bottom).

A display 108 (typically an LED digital display) is provided in the control panel 104, for example to display the current time and the remaining cooking time; however, it will be appreciated that many forms of display may be used, such as an LCD. A plurality of control/selection buttons 110, dials 112 and door release switches 114 are also provided. According to an embodiment of the present invention, the control/selection button 110 and the door release switch 114 are of a momentary switch type, or more preferably, a tactile switch type. Those of ordinary skill in the art will appreciate that well-known membranes, touch or touch switch components, any or any other similar switch types may be used.

Referring to fig. 1(b), there is shown a top view of the microwave oven after the door is opened, i.e., after the user actuates the door release switch 114 or after otherwise activating the door opening mechanism, as will be described subsequently. Thus, the door opening may be at an angle θ on the order of 30-45 degrees, thus allowing the user to then fully open the door 102. Of course, the initial opening angle θ may be some finite angle less than 30 degrees, or may be greater than 45 degrees; it will be appreciated that the mechanism may open the door up to about 90 degrees (e.g. for an on-board appliance) or may open more (e.g. up to about 180 degrees for a stand-alone unit).

Fig. 2 shows a part of an electrical system for the microwave oven of fig. 1. It can be seen that the circuit includes a controller 202 (e.g., a microprocessor controller). Connected to the controller 202 are a clock generator 204, a cam position switch 216, a touch switch 206, and an IR receiver module 208. The controller 202 also receives at one of its inputs a signal from the microwave power circuit via line 210 indicating whether the microwave power within the appliance is off or on. As is conventional, the controller may be connected to RAM, ROM, or other suitable storage device (not shown) that stores, among other things, system settings and settings (e.g., auto-on, time delayed auto-on) entered by a user via the control panel 104 (FIG. 1).

Based on the input status from the touch switch 206 and the IR receiver module 208, the controller 202 controls actuation of the rotation motor 212 via the driver circuit 214. Thus, the controller 202 is able to perform multiple modes of door opening:

(i) open after a user actuates the touch switch;

(ii) automatically turning on after microwave power is turned off;

(iii) automatically turning on after the microwave power is turned off for a period of time; and

(iv) open after receiving instructions via the IR remote controller.

Alternatively, the door may be opened by some other predetermined procedure, such as prompting the user to stir or turn the food product currently being cooked (or any other hardware input or internal decision by the controller).

A pseudo-code description of but one example of a procedure used by the controller 202 to control the actuation of the rotary motor 212 is shown in appendix A hereinafter. It will be appreciated by those of ordinary skill in the art that other suitable programs may be used to implement some or all of the techniques according to embodiments of the present invention.

Upon actuation of the rotation motor 212, the controller 202 will keep the rotation motor 212 operating until a signal is fed back to the controller 202 to stop the rotation motor 212. According to an embodiment of the present invention, a feedback signal from the cam position switch 216 indicates that the cam 302 (see FIG. 3) is in the correct start/stop position. In another embodiment, there may be feedback from the clock generator 204 indicating that the time limit timing marker has elapsed.

If power to the rotation motor 212 is turned off at any time, the controller 202 checks (by checking the state of the cam position switch 216) whether the cam 302 (see FIG. 3) is in the correct start/stop position when power is regained. If not, the controller 202 starts the rotation motor 212 until the cam 302 is in the correct start/stop position.

Fig. 3 illustrates a partial internal view of the microwave oven of fig. 1, showing a door opening mechanism and its operation according to an embodiment of the present invention, in which (a) the overall configuration of key members, (b) in a case where the door is located at a closed position, (c) in a case where it is located at a half stroke position, and (d) in a case where it is located at an open position.

Referring to fig. 3(a), the body of the rotation motor 212 is mounted to the raised tab 326 of the door hook molding 327. The rotary motor 212 comprises a shaft (not shown) whose free end is held directly by a hollow raised tab (not shown) below the door hook moulding 327, which thus acts as a sleeve. Mounted on the shaft (not shown) of the rotary motor 212 is a cam 302 that acts on a hook spacer 308. As described further hereinafter, during a door opening procedure in which the shaft of the rotary motor 212 rotates, the hook spacer 308 is caused to simultaneously act on the door key 316 attached to the door 102.

In fig. 3(b) -3(d), the rotary motor 212 is removed for clarity. Fig. 3(b) shows a cam 302 and its arms or projections 303 with smoothly rounded ends 304. Between adjacent ends 304 is defined a camming surface 306 (parallel to the axis of rotation), the camming surface 306 having a particular profile that abuts a matching radiused profile 310 of the hook spacer 308 during door opening motion. In fig. 3(b), the cam 302 is shown in the correct start/stop position for the door opening procedure. During a door opening action, the cam surface 306 and the profile of the hook spacer 310 slide against each other, forcing the hook spacer 308 to rotate (clockwise) about the axis 312 and the first angled portion 314 of the hook spacer 308 abuts and pushes the tip 318 of the door key 316 upward. The profile of each cam surface 306 and the profile of the hook spacer 310 are specially designed so that the cam 302 drives the hook spacer 308 while rotating in both clockwise and counterclockwise directions.

Thus, at the half-stroke position (fig. 3(c)), via the rotary motor 212 and cam 302 operating in a clockwise manner as shown by arrow a, the door key 316 attached to the door 102 (which is under the influence of a biasing spring (not shown) urging it open) moves upward in the direction of arrow B and approaches the release point of the door 102. It can also be seen that a coil spring 320 is provided which is centered on the axis 312 and has one end secured to the door hook molding 327 by a clamp 324. The other end (not shown) of coil spring 320 is attached to hook spacer 308 at location 322 and acts on hook spacer 308 to return hook spacer 308 after tip 304 of cam arm 303 passes apex 309 of hook spacer 308 to the "door open" position where face 338 abuts hook spacer stop 330.

Referring to fig. 3(d), at the point indicated therein, the door is effectively released: the tip 318 of the door key 316 has passed the corner 332 of the hook spacer 308 and the door key 316 is free to move. The door key 316 is pulled down (i.e., in the direction of arrow C) along the sloped section 334 of the hollow channel of the door hook molding 327 by the urging of a coil spring (not shown) positioned within the door housing (not shown) and acting downwardly on the door key 316, thereby pushing the door 102 to the open position (in fig. 3(d), indicating that the door is partially open at a small angle).

Subsequently, after the door opening procedure, the cam 302 continues to rotate until one of the rounded tips 304 of the cam arm 303 compresses and actuates the microswitch 216 at point 336. At this point, the cam 302 is in the correct start/stop position to receive the hook spacer 308 when the door is next closed, i.e., in the same relative position as when the door opening procedure begins (see fig. 3 (b)).

If the power to the rotation motor 212 is turned off for any reason, the user can manually override the opening mechanism and manually open the door 102 at any time by pulling. If the power to the swing motor 212 is interrupted during the door opening sequence, the swing motor 212 can still close the door 102 because the door key 316 (if needed) can move the swing motor 212 and cam 302 when closing the door 102.

Appendix A

While the system is operating

Detecting a cooking power state; detecting a touch switch state; detecting an IR receiver state; detecting an automatic open setting; detecting a door opening state; detecting a cam position state;

if the door is opened

Not setting the actuator control signal high

If the touch switch is high, or the IR receiver is high;

setting actuator control signal high

If the auto-on setting is made on

Acquisition time auto-on time period

If the auto-on time period is zero and the actuator control signal is low

Then the actuator control signal is set high

Or carry out

Automatic on time period countdown

When the auto-on time period has not ended

When the auto-on time period has not ended.

Claims (19)

1. A door opening mechanism for a domestic appliance comprising a housing, a front door and a resilient member for forcing the door open,

wherein the door opening mechanism is located within the housing; the door opening mechanism includes:

a rotary motor for driving a member in response to a control signal;

characterised in that the door opening mechanism further comprises a retaining mechanism engageable with the door and movable between a first configuration in which the door is retained or can be retained in a closed position and a second configuration in which the door is not engaged;

a cam having a plurality of cam surfaces, each cam surface being capable of moving the retaining mechanism away from the first configuration via a camming action, the cam being a member driven in use by the rotary motor;

the door comprising a door key comprising a tip engageable with an edge of the ramped section of the hollow slot of the door hook molding and configured to enable a user to manually override the opening mechanism and open the door by pulling;

the holding mechanism includes:

a rotatable member (308) rotated by the cam while the motor is actuated in use; and

a second spring biasing element (320);

wherein in use, during at least a portion of movement of the retaining mechanism between the first configuration and the second configuration, the second spring biasing element (320) acts to urge the retaining mechanism into the first configuration;

the rotatable member having a guide surface (314) comprising a transition point and configured such that, in use, a door key (316) attached to the door is capable of sliding contact with the rotatable member along the guide surface;

wherein after the door key slides beyond the transition point, a force caused by gravity and the resilient member operates on the door such that the door rotates to a partially open position.

2. The door opening mechanism of claim 1, wherein the cam includes a plurality of equally angularly spaced projections, an outer surface of the cam between adjacent projections including a cam surface.

3. A door opening mechanism according to claim 1 or claim 2, wherein each cam surface includes two ramps, one for clockwise cam movement and the other for anticlockwise cam movement, the two ramps interacting with the retaining mechanism as it moves between the first and second configurations.

4. The door opening mechanism of claim 1 or 2, wherein each of the cam surfaces comprises: a first portion for cooperating with the retaining mechanism when the retaining mechanism is moved to the first configuration, and a second portion for cooperating with the retaining mechanism when the retaining mechanism is moved from the first configuration to the second configuration.

5. The door opening mechanism of claim 2 or claim 3 when claim 3 is dependent on claim 2, wherein each of the projections forms a transition point between the first configuration and the second configuration.

6. A door opening mechanism as claimed in claim 2 or claim 3 when dependent on claim 2, wherein each projection forms a transition point between a first portion of one cam surface and a second portion of an adjacent cam surface.

7. The door opening mechanism of claim 1, wherein the resilient member comprises a first spring biasing element.

8. The door opening mechanism of claim 1, wherein the rotatable member (308) includes an engagement surface (310) for sliding engagement with a cam surface on the cam in use.

9. The door opening mechanism of claim 1, wherein the motor is operable in two directions, thereby moving the retaining mechanism in either of the two directions.

10. A domestic appliance, the domestic appliance comprising:

a housing;

a front door;

a resilient member for urging the door open, the resilient member comprising a first spring-biasing element; and

the door opening mechanism of claim 1;

a controller connected to the motor, the controller operable in response to one or more signals to actuate the motor via an actuator and thereby cause the door to move open.

11. The household appliance of claim 10, further comprising a microswitch positioned to be engaged by an adjacent tab and to be in a closed state when the retention mechanism is in the first configuration.

12. The domestic appliance of claim 10, wherein,

the controller is operable in a switch actuation mode;

the shell is provided with an electric switch which is connected to the controller and can be operated by a user; and is

The controller is operable, in use, to actuate the actuator when the detection signal from the electrical switch is high.

13. The domestic appliance of claim 10, wherein,

the controller is operable in a remote actuation mode;

a wireless receiver unit connected to the controller and operable by a user remote unit is provided on the housing; and is

The controller is operable, in use, to actuate the actuator when the detection signal from the wireless receiver unit is high.

14. The domestic appliance of claim 10, the appliance being capable of performing temporary electrical operations, wherein,

the controller is operable in an auto-on mode;

a user selection interface is provided on the housing and is connected to the controller and is operable by a user, the user selection interface including an auto-open setting selectable by the user in use;

the controller is connected to receive input signals indicative of whether electrical operation in the appliance is on or off, respectively; and is

The controller is operable in use to actuate the actuator when the received signal is low.

15. The domestic appliance of claim 10, the appliance being capable of performing temporary electrical operations, wherein,

the controller is operable in a delayed auto-on mode;

the controller is connected to a storage device for storing a time period;

the controller is connected to receive input signals indicative of whether electrical operation in the appliance is on or off, respectively; and is

The controller is operable, in use, to actuate the actuator when the controller determines that (a) the received signal is low and (b) the time period has elapsed.

16. The appliance of claim 15, wherein the user selection interface includes a delayed auto-on setting selectable by a user when in use;

wherein the user selection interface is operable by a user to input the time period before storage in the storage device.

17. The domestic appliance of claim 15 or 16 wherein the time period is (a)1 to 20 seconds, (b) up to 1 minute, or (c)1 to 5 minutes.

18. The appliance of claim 10, wherein, as a further alternative operable in response to the detected or received signal being high, the controller is operable to make any predetermined detectable change in the state or voltage level of the detected or received signal in response to (a) the detected or received signal being low, or (b) the detected or received signal.

19. The household appliance of claim 14, wherein the appliance is (a) an oven and the temporary electrical operation is cooking by any combination of microwave, baking, convection or steaming, or (b) a bread maker, a yogurt maker and the temporary electrical operation is electrical warming or heating.