Abstract:
The device comprises a hook ( 2 ) connected to the door ( 5 ) and a support structure ( 1 ) in which is defined an aperture ( 4 ) for the introduction of the hook ( 2 ) and in which are mounted: a rotatable member ( 6 ) biased by a spring ( 12 ) and operable to retain a hook in a closure position of the door ( 5 ) and to release this hook ( 2 ); and a control device ( 14 - 16 ) including a pawl ( 15 ). When, with the door ( 5 ) closed, a force is applied to the hook ( 2 ) in the direction such as to open the door ( 5 ), the rotatable member ( 6 ) is initially free to turn, against the action of the spring ( 11 ), with respect to an auxiliary body ( 9 ), to a position in which the rotatable member ( 6 ) releases the auxiliary body ( 9 ) from the pawl ( 15, 19 ), and then to turn, together with the auxiliary body ( 9 ) and under the action of the spring ( 11 ), to release the hook ( 2 ).

Description:
This is a National stage entry under 35 U.S.C. § 371 of Application No. PCT/EP01/04517 filed Apr. 20, 2001; the disclosure of which is incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   The present invention relates to a door lock device for a domestic electrical appliance, in particular for washing machines and/or tumble dryers, of the type defined in the introductory part of the annexed claim 1. 
   SUMMARY OF THE INVENTION 
   One object of the invention is to provide a door lock of this type which is of reliable operation, a simplified structure and a small size. 
   These and other objects are achieved according to the invention with a door lock device, the essential characteristics of which are defined in the annexed claim 1. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the invention will become apparent from the following detailed description given purely by way of non-limitative example, with reference to the attached drawings, in which: 
       FIG. 1  is a partially sectioned side view of a door lock device according to the invention, shown in the configuration with the door still open; 
       FIGS. 2 and 3  are perspective views of the internal mechanism of the door lock device shown in  FIG. 1 ; 
       FIG. 4  is a sectional view taken on the line IV—IV of  FIG. 1 ; 
       FIG. 5  is a perspective view, on an enlarged scale, of a rotary cam member of a device according to the invention; 
       FIG. 6  is view similar to that shown in  FIG. 1 , and shows the door lock device in the door-closed condition; and 
       FIGS. 7 and 8  are views similar to those of  FIGS. 1 and 6  and show the door lock device in two successive operating phases of emergency opening of the door. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   With reference to  FIG. 1 , the illustrated exemplary embodiment of a door lock device according to the invention comprises a support structure  1  within which the mechanism generally indicated  3  is mounted. 
   The support structure  1  is essentially in the form of a rectangular container with an aperture  4  through which a hook  2  connected to door  5  of the domestic electrical appliance can be introduced. 
   The door lock device is intended to be mounted on the domestic electrical appliance at the opening with which the door  5  is associated. 
   The internal mechanism  3  within the structure  1  comprises a cam member  6  which is rotatably mounted about a pin  7  which is stationary with respect to the support structure  1 . In particular, the pin  7  is engaged in a curvilinear slot-like opening  8  of the cam member  6 . 
   Associated with the cam member  6  is an auxiliary body  9  which embraces this cam member as better seen in  FIGS. 2 and 3 . The auxiliary body  9  is also rotatably mounted about the pin  7 . Moreover, the auxiliary body  9  is articulated to the cam member  6  about a secondary axis which is movable with respect to the support structure  1 , this axis being essentially represented by a pin indicated  10 . As can be seen in particular from  FIG. 1 , the shape of the curvilinear slot  8  of the cam member  6  is essentially an arc of a circle centred on the axis of the pin  10 . 
   A torsion spring  11  is disposed about the pin  10  and its end portions  11   a  and  11   b  react one against the cam member  6  and the other against the associated auxiliary body  9 , tending to maintain them in the relative angular position shown in  FIG. 1 . 
   A further torsion spring  12  is disposed around the pin  7  and has an end  12   a  which reacts against a stop la of the support casing  1  ( FIG. 1 ) and another end  12   b  which reacts against the auxiliary body  9  ( FIGS. 2 and 3 ). The spring  12  tends to cause the body  9  and the cam member  6  to rotate about the stationary pin  7  in an anticlockwise sense as viewed in  FIG. 1 . 
   The cam member  6  has a recess or cavity  13  at its end, between two arms  6 a and  6 b. 
   The recess or cavity  13  can receive a transverse end part  2   a  of the hook  2  connected to the door  5 . 
   With reference in particular to  FIGS. 1 to 4 , a further pin mounted in a stationary position in the support casing  1  is indicated  14 . A pawl  15  is rotatably mounted about this pin. 
   The pins  7 ,  10  and  14  are essentially parallel to one another. 
   A torsion spring  16 , disposed about the pin  14  has an end  16   a  which reacts against a stop  17  formed in support casing  1 , and another end  16   b  which reacts against the pawl  15 , tending to press it towards the cam member  6  and the associated auxiliary body  9 . 
   As better seen in  FIGS. 2 and 3 , the pawl  15  has a pair of end teeth indicated  18  and  19 . These teeth are essentially parallel, facing one another and spaced in a direction transverse the length of the pawl  15 . 
   As will appear more clearly hereinbelow the tooth  18  is an exploration or feeler tooth intended to co-operate with the profile of the cam  6  which will be described hereinbelow. 
   The tooth  19 , on the other hand, is a stop tooth, intended, in some operating conditions, to co-operate with a corresponding tooth  9   a  ( FIG. 2 ) of the auxiliary body  9 , to retain this latter in a predetermined angular position ( FIG. 6 ) corresponding to closure of the door  5 . 
   With reference in particular to  FIG. 5 , the rotatable member  6  is provided at its top with a plurality of cam profiles intended to co-operate with the tooth  18  (here shown in broken outline in three different operating positions) of the pawl  15 . 
   In particular, the upper part of the rotatable member  6  has a convex, arcuate, longitudinal sliding surface  20 . On one side of the stop surface of the member  6  extends a longitudinal wall  21  essentially orthogonal to the sliding surface  20 . From the wall  21  extends a control profile  22  of sinuous shape, which becomes progressively spaced from this wall, and which extends up to a small step  23  which marks a transition from the sliding surface  20  to a slightly elevated surface  24 . From this surface  24  extends a first ascending ramp  25  which rises in the direction of a peak  26 . A stop surface  27 , essentially parallel to the wall  21 , extends between one side of the ramp  25  and one side of the further ascending ramp  28  longitudinally offset with respect to the ramp  25 . The ramp  28  lies between the stop surface  27  and one end of the wall  21 . This wall has a greater height than the surface  29 , which is reached from the top of the ramp  28 . 
   With reference to  FIGS. 2 and 3 , the spring  16 , as well as acting as a torsion spring, also acts as a thrust coil spring on one wing  15   a  of the pawl  15 , thus pressing the whole pawl in the direction of the arrow F 1  of  FIG. 2  in such a way that the feeler tooth  18 , in operation and depending on the angular position of the cam member  6 , is thrust into contact with the wall  21  or with the profile  22 , the stop wall  27 , or the wall  21  again. 
   The door lock device described above operates substantially in the following manner. 
   In  FIG. 1  the device is shown in the door-open condition with the hook  2  connected to the door  5 , disengaged from the rotatable member  6 . In this condition the cam member  6  and the associated auxiliary body  9 , under the action of the springs  11  and  12 , assume the relative angular positions illustrated in which the body  9  abuts against a stop  1   b  and the feeler tooth  18  of pawl  15  engages the end portion of the wall  21  in correspondence with the transversely wider part of the sliding track  20 . 
   To close the door, this latter is pressed in such a way that the hook  2  enters into the cavity  13  of the cam member  6  causing rotation of this latter and of the auxiliary body  9  about the pin  7 . During this rotation the feeler tooth  18  of the pawl  15  is displaced following the sinuous path of the control profile  22  of the cam member, at the end of which, under the thrust of the spring  16 , it moves forward to the step  23 , which rises to contact against the stop surface  27 , again under the action of the spring  16 . When the feeler tooth  18  has reached this position ( FIG. 3 ) the associated locking tooth  19  engages the tooth  9   a  of the auxiliary body as is shown in  FIG. 2 , preventing the return rotation of this auxiliary body and the cam member  6 . The door  5  is held in the closure position as is shown in  FIG. 6 . 
   In this condition it is possible to cause reopening of the door  5  by exerting on it a pressure from outside (opening in the so-called ‘push-push’ manner). The thrust exerted on the door  5  causes a clockwise rotation, as viewed in  FIG. 6 , of the cam member  6  and the associated auxiliary body  9  about the pin  7 . Following this rotation the feeler tooth  18  of the pawl  15  leaves the stop surface  27  and, pressed transversely by the spring  16 , comes into contact against the end of the wall  21  adjacent to the ramp  28 . This lateral displacement of the pawl causes disengagement of the locking tooth  19  from the auxiliary body  9 . This body  9 , with the cam member  6  engaged by it, is then caused to rotate towards the opening position of the door by the action of the spring  12 . During this rotation the feeler tooth  18  of the pawl  15  rises up the ramp  28  and slides on the surface  29  in contact with the top portion of the wall  21 , until at the end of the surface  29  it falls back onto the sliding surface  20 . The device is thus returned to the condition shown in  FIG. 1  and the door is openable. 
   When the door is retained in the closure position shown in  FIG. 6 , the device allows the door  5  to be opened by the effect of a thrust acting on it from within the machine. This function is useful, for example, to allow opening in an emergency by a child who may possibly have entered the machine and closed its door. 
   In the door-closed condition ( FIG. 6 ) the feeler tooth  18  of the pawl  15  presses against the stop surface  27  adjacent the ramp  25 . A force exerted on the hook  2  in the opening direction of the door  5  causes rotation of the cam member  6  about the pin  10 . During this rotation (see the intermediate position shown in  FIG. 7 ) the feeler tooth  18  of the pawl  15  slides on the ramp  25  ( FIG. 5 ) and rises to the top of the projection  26  ( FIG. 8 ). Consequently, the associated stop tooth  19  of the pawl  15  disengages itself from the auxiliary body  9 . This body, no longer restrained, can now turn together with the cam member  6  into the angular position of  FIG. 1  in which it allows disengagement of the hook  2  and opening of the door  5 . 
   The mechanism is conveniently formed in such a way that, by choosing the width of the slot  8  of the cam member  6  and the position of the projection  26  in relation to the feeler tooth  18  of the pawl, there is a predetermined neutral stroke before release of the door from within the apparatus. This characteristic gives the device a certain operating stability and allows for compensation of possible dimensional variations (due for example to ageing) of the seal or seals associated with the door  5  with reference to the balanced door-closed position. 
   In a manner not illustrated in the drawings, the device may have an associated electric microswitch with an operating member which can be engaged, for example by the auxiliary body  9 , when the device is in the door-closed position, for the purpose, for example, of generating a signal and/or providing an enabling signal allowing activation of the domestic electrical appliance. 
   Naturally, the principle of the invention remaining the same, the embodiments and details of construction can be widely varied with respect to what has been described and illustrated purely by way of non-limitative example, without by this departing from the ambit of the invention as defined in the annexed claims.