Appliance with hinged door

Abstract

An appliance is provided with a hinged door (1), which closes a compartment provided with a perimetral seal (24) on which the door (1) goes into abutment, and a motorised latch comprising a motor (20) which operates a hook (15) swinging around a pin (16) between a locking position, in which it engages an eyelet (14) of the door (1) pulling the door (1) inwards until it compresses the seal (24), and a position in which it does not engage the eyelet (14), the oscillation between the locking position and the disengagement position implying a push of the hook (15) on the eyelet (14) such as to cause the door (1) to be detached from the seal (24).

Description

[0001] The present invention relates to an appliance, for domestic or professional use, provided with a hinged door which is automatically locked and unlocked by means of a motorised latch. In the following, specific reference will be made to a dishwasher, but it is clear that the invention can be applied to other types of appliances comprising the same type of door (e.g. thermo-disinfectors, washing machines, refrigerators, ovens, etc.).

[0002] It is known that there are appliances in which the compartment that is closed by the hinged door has a perimeter seal that the door must compress when closing, for example to prevent the escape of water and steam in a dishwasher, or hot air and / or steam in an oven. This compression action can be performed manually by the user or automatically by a motorised device for the door opening and closing , which requires also a safety control to prevent the door from damaging an obstacle (an object or an operator) that could be found in its path.

[0003] To this end, the presence of the obstacle is typically detected through the increase in the motor torque required to move the door, which has a two-way connection with the motorised device that controls its movement. In practice, the safety control is entrusted only to a sensor that detects the increased absorption due to an obstacle, so as to interrupt / reverse the operation of the motor beyond a certain overload threshold.

[0004] A traditional latch that merely locks and unlocks, with a simple manually operated mechanism or a motorised device, the door in the closed position with the seal in a compressed condition, is inadequate when the seal creates problems when opening and / or closing the door.

[0005] A first drawback can arise when the seal becomes stiffer as it ages, requiring a greater push to compress it. In such a case, the manual closure requires a greater effort by the user, while in the case of a motorised door, if the safety control intervention threshold is not raised to take account of this increased push, a "false positive" may occur, i.e. the detection of a non-existent obstacle, with the result that the device is unable to close the door.

[0006] A second similar drawback that can occur at the beginning of the opening phase is that the aged seal tends to stick to the door, thus requiring a greater initial effort by the user or the motorised device. This leads to a risk of "false positive" if the threshold is too low, as an obstacle is detected in the opening process that is not there, with the result that the device is unable to open the door.

[0007] On the other hand, adjusting the threshold to suit the aged seal is not easy either, as it is necessary to proceed by trial and error and the threshold may be adjusted so high that it risks damaging an obstacle.

[0008] Finally, there are other types of safety control using different means, such as an infrared barrier or a contact-sensitive moving edge, which are however much more expensive and complex to operate.

[0009] US 2004 / 163684 and DE 4319518 disclose dishwashers with motorised latches that overcome the first drawback but not the second drawback, since their latches merely unlock the door without rotating it outward. Therefore, it is left to the user or the motorised device to address the issue of a seal sticking to the door.

[0010] WO 2017 / 200680 discloses a dishwasher with a motorised latch that overcomes both the first and second drawbacks, but has other drawbacks of its own. In fact, the latch essentially consists of a plunger provided at its distal end with an eye that may be captured by a spring-loaded tooth extending upward from an upper edge of the door and retractable by pulling on a door release lever. This means that the engagement and disengagement between the latch and the door is not automatic but rather requires a manual effort by the user, thus resulting in the drawback that the opening and closing process cannot be fully automated.

[0011] The plunger is longitudinally moved through a rack gear formed on one side of its proximal end and engaging with a rotatable pinion that is rotated by a gear train driven by a DC motor. When the plunger and the door are at the sealed position, a pressure inward on the door at any time moves the plunger inward to an actuation position, this being possible by slight compliance by the gasket and some intentional play in the gear train, for example by more than 6 mm, for signaling to the dishwasher that the consumer desires to open the door.

[0012] Such a mechanism is rather delicate and complex, in addition to being rather bulky, because the amount of play may increase over time and also lead to uneven wear of the gears in the gear train. This results in the drawbacks of poor reliability and possible unintentional activation by the user, e.g. simply by leaning on the door.

[0013] The object of the present invention is therefore to provide an appliance having a motorised latch which overcomes these drawbacks. This object is achieved by means of an appliance in which the door latch actively assists in compressing the seal in the closing phase and detaching it from the door in the opening phase, without requiring any manual intervention for the engagement and disengagement between the latch and the door.

[0014] The main advantage of the appliance according to the present invention is therefore that of having a latch that directly provides the interventions on the seal both in the opening and closing phase. In this way, the ageing of the seal does not require a greater effort by the user nor affects the correct functioning of the safety control of the possible door movement device, without risk of "false positives" or damage to an obstacle due to an excessively high intervention threshold.

[0015] A further significant advantage of this appliance stems from the fact that the latch is extremely simple and therefore reliable and inexpensive, and its operation is very easy to control by the control unit.

[0016] Still another advantage resides in the possibility of full automation of the opening and closing process, in the preferred embodiment including a sensor that detects the presence of the door when it arrives in proximity to the latch in a position where it can be engaged by the latch.

[0017] These and other advantages and features of the appliance according to the present invention will be evident to those skilled in the art from the following detailed description of an embodiment thereof, with reference to the accompanying drawings in which: Fig.1 is a schematic view of the main elements of the latch of an appliance according to the invention, during the door engagement phase; Fig.2 is a similar view to the previous one, in the condition of locking the door and compressing the seal; and Fig.3 is a similar view to the previous one, in the condition of unlocking the door and detaching it from the seal.

[0018] Referring to Fig.1, it can be seen that the latch acts on a horizontal eyelet 14, fixed to the hinged door 1 which rotates around a bottom horizontal axis; eyelet 14 is engaged by the free end of an inverted hook 15 swinging around a horizontal pin 16, under the action of a connecting rod 17 pivoted at the other end of hook 15. The connecting rod 17 is pivoted at its opposite end to a crank of a crankshaft 18, which rotates counterclockwise about a horizontal axis 19 being driven by a unidirectional motor 20.

[0019] The engagement position of Fig.1 is preferably confirmed by means of a sensor that detects the presence of door 1 when it arrives in the vicinity of the latch in such a position that eyelet 14 can be engaged by hook 15, preferably a Reed sensor (not shown) that detects a magnet 23 mounted on door 1. A control unit (not shown), once it receives confirmation from the aforementioned position sensor, activates motor 20 so that the rotation of crankshaft 18 causes the backward movement of the connecting rod 17 which rotates hook 15 clockwise around the pin 16.

[0020] Consequently, hook 15 pulls inwards eyelet 14 and therefore door 1, which compresses seal 24 without the need for a push by the user or the motorised device of door 1. A microswitch (not shown) is actuated by hook 15 when the fully closed position of door 1 is reached in which seal 24 is compressed (Fig.2), so as to authorize the start of the operating cycle of the appliance.

[0021] The crankshaft 18 is also provided with a cam profile 21 that is able to operate a second microswitch 22 that is used to detect the position in which hook 15 has disengaged from eyelet 14 (Fig.3), so as to authorize the activation of the motorised device for the start of the opening phase, or to signal to the user that door 1 can be opened manually. Note that in the passage from the locked position of Fig.2 to this disengagement position, the central portion of hook 15 comes into contact with eyelet 14, pushing it outwards, whereby door 1 is detached from seal 24 even before the start of the opening phase.

[0022] It is clear that the embodiment of the appliance according to the invention described and illustrated above is only an example susceptible to numerous variations. In particular, the exact nature, form and arrangement of the elements could be varied according to specific constructional requirements, for example by using mechanical equivalents of the elements described above such as a different type of sensor / detector than the Reed sensor and microswitches 12, 22 (e.g. optical sensors, resistive sensors, etc.), a different type of actuator than unidirectional motor 20 and so on, as long as the general structure of the latch is maintained with an engagement element that actively pulls inwards door 1 in the closing phase and pushes it outwards in the opening phase.

[0023] Similarly, the rotation mechanism of hook 15 could also be different from the connecting rod 17+crankshaft 18 combination, and the rotation pin 16 of hook 15 could be vertical if the mechanism is intended to act on an eyelet 14 arranged in the vertical plane. Alternatively, hook 15 could be reversed and pivot 16 located below eyelet 14 to engage it from below, in which case motor 20 would rotate clockwise.

Claims

1. An appliance having a hinged door (1), which closes a compartment of the appliance provided with a perimetral seal (24) on which said door (1) goes into abutment, and a motorised latch comprising an actuator which operates an engagement element which locks and unlocks the door (1) by engaging and disengaging a corresponding engagement element of the door (1), said engagement element of the motorised latch being connected to said actuator and arranged relative to said engagement element of the door (1) so as to engage the door (1) in order to make it perform the last stretch of the closing stroke and the first stretch of the opening stroke, the length of said stretch performed by the door (1) under the action of the motorised latch being sufficient to obtain the compression of said seal (24) in the closing phase and the subsequent detachment of the door (1) from the seal (24) in the opening phase, characterized in that the engagement element of the door (1) is an eyelet (14) and the engagement element of the latch is a hook (15) swinging around a pin (16), parallel to the plane of said eyelet (14), between a locking position in which it engages said eyelet (14) pulling the door (1) inwards until it compresses the seal (24), and a position in which it does not engage said eyelet (14), the oscillation between said locking position and said disengagement position implying a push of the hook (15) on the eyelet (14) such as to cause the door (1) to be detached from the seal (24).

2. Appliance according to the preceding claim, characterized in that the hook (15) oscillates under the action of a connecting rod (17) pivoted between the hook (15) and a crank of a crankshaft (18) driven by a unidirectional motor (20).

3. Appliance according to the preceding claim, characterized in that the crankshaft (18) is provided with a cam profile (21) arranged to actuate a microswitch (22) in correspondence with the disengagement position of the hook (15), said microswitch (22) being operatively connected to the control unit to signal the unlocking of the door (1) and / or to authorize the activation of a movement device of the door (1) for starting the opening phase.

4. Appliance according to any of the preceding claims, characterized in that it further comprises a microswitch which is activated by the hook (15) in correspondence with its locking position, said microswitch being operatively connected to the control unit so as to authorize the start of the operating cycle of the appliance.

5. Appliance according to any of the preceding claims, characterized in that it further comprises a sensor that detects the presence of the door (1) when it arrives in proximity to the latch in a position where it can be engaged by the latch, preferably a Reed sensor that detects a magnet (23) mounted on the door (1).

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