The present invention is a door opening mechanism for a household appliance, oven in particular. The mechanism allows for an automatic opening of the door of an oven or other household appliance, released for example with a button on a control panel or a sensor located on the surface of the handle or connected to the handle.

Known are door locks that enable keeping the door in a closed position and preventing the door from being opened by the user. For example, a European patent no. EP2479364 describes a solution, in which thp door is locked by cooperation of the locking ledge located on the appliance door with a lock located in the body of the appliance. The lock is equipped with a profile hook, whose rotation is controlled by the slider on a spring. The door is locked by blocking the movement of the slider by an electromechanism with a moving catch.

Known is also a solution described in the Polish patent no. PL216474 B1 , where the lock is located in the lock housing located on the body of a household appliance. The lock is equipped with closing arms, each mounted on a separate axis of rotation, free sections of which protrude from the housing and are pivoted to each other. The arms are received in the closing throat located in the door, where they enter upon closing. In the throat there are deflecting surfaces that cause the free sections of the arms being reclined relative to each other. However, it is not impossible to reverse this system and put the closing throat on the body of the appliance, and the lock on the door. The result of such design is, among others, allowing automatic opening of the door either by a screw mechanism driven by a motor that causes clamps closing or a pin on the actuator that pushes the door from the closed position.

In the solution EP2479364B1 , the door is released for opening by the user, however, automatic door opening is impossible. This solution is mainly used in washing machines. The lock in solution PL216474 B1 in versions enabling automatic opening of the door consists of a number of components and has a complicated design.

The purpose of the invention is to develop a door opening mechanism for a household appliance, oven in particular, allowing automatic opening of the door while keeping the possibility to open them manually.

Door opening mechanism for a household appliance, oven in particular, consisting of a lock mounted in the body of the appliance, profile element located on the appliance door and, located between the body and the door element exerting permanent force on a closed door in the direction of opening, characterised in that the lock consists of a rigid base, positioning other components, a pair of closing arms mounted on one axis built in the base, and intersecting with each other in the mounting location, that in the front part, between the pivot axis and the appliance door, have hook-shaped ends forming a clamp, and two helical pressing springs, whose ends are mounted respectively to the rear part of the closing arm and the adjacent to the arm side wall of the base, a cam mounted on a drive shaft located between the rear parts of the closing arms and a cam position sensor. Hookshaped ends of the front part of the closing arms are located at the pin attached to the upper door rail of the appliance, which is a profile element of the appliance door opening mechanism. When the appliance door is closed, the hook-shaped ends of the closing arms catch the pin, press the door to the gasket of the body of the appliance, and retain the door in a closed position. The door opens following rotation of the cam to the position of maximum opening of the clamps of the closing arms and the pin release.

It is advantageous if the pin has a shape of a deltoid with rounded vertices.

It is also advantageous if the long sides of the pin are closer to the body of the appliance. In this way, the smaller lead angle during door closing allows to reduce the force required to close it, while larger lead angle when opening the door makes the force pressing the door to the housing gasket ensures the closure, and at the same time requires the use of sufficient force to open the door of the machine. This reduces the risk of accidental, uncontrolled door opening.

The advantage of the door opening mechanism according to the invention is a simple design consisting of few elements, which translates into relatively low cost of its production. The mechanism allows both automatic door opening and manual opening at any time of the appliance operation. Furthermore, the mechanism has a neat appearance and can be easily adapted to different types of the oven front.

The subject matter of the invention in an example embodiment is shown in the figure, where fig. 1 shows the mechanism in the closed position in a perspective view, fig. 2 shows the mechanism in a closed position in a view from the top, fig. 3 shows cross-section A:A of the mechanism shown in fig. 2, fig. 4 shows the mechanism in side view, fig. 5 shows cross-section B:B shown in fig. 4 of the mechanism in the closed position, fig. 6 shows cross-section B:B shown in fig. 4 of the mechanism in the open position, fig. 7 shows a perspective view of the oven and the location of the lock clamps, fig. 8 shows detail A shown in figure 7, fig. 9 shows the oven door from the appliance body side, fig. 10 is a schematic drawing of the pin from the top with clenched clamps.

The door lock mechanism of a household appliance, oven in particular, according to the present invention located such that the lock 13 is mounted in the front panel of the body 12 of the appliance, in such a way that its closing arms 2 are located at the height of the pin 8 located in the strip 9 of the door 1 1 . Closing arms 2 cooperate with the pin 8 as results of opening and closing the door 1 1 . In the embodiment, the lock 13 comprises a rigid base 1 in the form of a bearing plate, positioning other components of the lock 13. The base has the pivotally mounted pair of closing arms 2, mounted on a common axis 3. One of the closing arms 2 is "S"-shaped and the other one is shaped as an inverted "S", and are mounted one on top of the other on the same axis 3 built in the base 1 , intersecting each other in the place of mounting, in the middle of their length. Arms 2 have vertical ends 2c of the rear parts of the arms 2b, and the free parts of the front section 2a of the closing arms 2 extending below the base of the lock 1 are the hookshaped ends forming clamps cooperating with the pin 8 located on the door 1 1 . Lock 13 has two helical pressing springs 4, the ends of which are mounted respectively to the vertical ends 2c of the rear part 2b of the closing arms 2 and adjacent to the arms 2 side walls 1 a of the base 1 , on which they are based, while being mounted on a tongue located on this side wall 1 a. These springs 4 press against the ends 2c of the rear parts 2b of the closing arms 2 and cause clenching of the front parts 2a of the closing arms 2. Opening the arms 2 may occur as a result of rotation of the cam 5 mounted on the drive shaft 6. Profile element is a pin 8 which is an integral element in the strip of the door 9. The pin 8 has a shape of a deltoid with rounded vertices, and its long sides 8a are directed towards the body 12 of the appliance. Closing arms 2 cooperate with the pin 8, whose shape is chosen so that at the moment of closing the door 1 1 the force required to close them is reduced, and exert a force pressing the door 1 1 to the gasket. To open the door 1 1 , a threshold force is required, and the door 1 1 can be opened only after this force is exceeded. Upon the command from the control system, the cam 5 is rotated by the drive 6 by an angle of 180°, thereby causing a temporary opening of the closing arms 2, thereby allowing automatic opening of the door, on which in the closed position a constant force is exerted in the direction of opening. In the embodiment, this element are hinges 10 mounted on the door 1 1 between the door 1 1 and the body 12 to allow movement of the door 1 1 .

Furthermore, the lock is equipped with a cam position sensor 7, which enables and disables the drive 6 when the cam when it reaches five right angle.