Drum washing machine with hinge units

Abstract

Disclosed herein is a drum washing machine. A rotational track of a first door to open and close an opening of a machine body is concentric with a rotational track of a second door to open and close an opening of a water tub, thereby improving user convenience.

1 . A drum washing machine, comprising:
 a machine body having a first opening;   a water tub disposed in the machine body, the tub having a second opening facing the first opening;   a rotary drum rotatably provided in the water tub to contain laundry;   a first door to open and close the first opening;   a second door to open and close the second opening;   a first hinge unit mounted at the machine body to rotatably support the first door; and   a second hinge unit mounted to the water tub to rotatably support the second door such that a rotational center of a rotational track of the second door coincides with a rotational center of a rotational track of the first door during opening of the second door.   
     
     
         2 . The drum washing machine according to  claim 1 , further comprising a coupling unit to couple the first door and the second door such that the second door is simultaneously opened when the first door is opened. 
     
     
         3 . The drum washing machine according to  claim 2 , further comprising a hook coupling part provided at the second door, and wherein the coupling unit is provided at the first door, and the coupling unit includes a hook unit configured to be hooked by and released from the hook coupling part provided at the second door. 
     
     
         4 . The drum washing machine according to  claim 3 , wherein the coupling unit further includes an actuator to release the hook unit from the hook coupling part. 
     
     
         5 . The drum washing machine according to  claim 4 , wherein
 the actuator includes a drive motor, a wire coupled to the drive motor, and an idle gear configured to be rotated by movement of the wire, and   the hook unit is rotated about a hook rotation shaft, the hook unit being provided at one end thereof with a hook gear engaged with the idle gear and at the other end thereof with a hook configured to be coupled to hook coupling part of the second door.   
     
     
         6 . The drum washing machine according to  claim 4 , wherein the actuator releases the hook unit during an operation of the drum washing machine in a state in which the first opening and the second opening are closed by the first and second doors. 
     
     
         7 . The drum washing machine according to  claim 6 , wherein the coupling unit further includes a hook holding lever to hold the hook unit released by the actuator to maintain a released state of the hook unit. 
     
     
         8 . The drum washing machine according to  claim 1 , wherein the second hinge unit has a rotational center located on the same axis as the rotational center of the first door. 
     
     
         9 . The drum washing machine according to  claim 8 , wherein:
 the first hinge unit includes first hinge arms provided at the machine body such that the first hinge arms are vertically spaced apart from each other, each of the first hinge arms having a first rotation shaft hole formed at an end thereof, and second hinge arms provided at the first door such that the second hinge arms are vertically spaced apart from each other, each of the second hinge arms having a second rotation shaft hole formed at an end thereof such that the second rotation shaft hole is aligned with the corresponding first rotation shaft hole, the first hinge unit further including a first hinge shaft coupling the first hinge arms and the second hinge arms at the first and second rotation shaft holes, and   the second hinge unit includes third hinge arms provided at the water tub such that the third hinge arms are vertically spaced apart from each other, the third hinge arms extending from the water tub toward a front of the machine body such that the third hinge arms reach positions corresponding to the first rotation shaft holes, each of the third hinge arms having a third rotation shaft hole formed at an end thereof, and fourth hinge arms provided at the second door such that the fourth hinge arms are vertically spaced apart from each other, the fourth hinge arms being bent from the second door and extending toward the front of the machine body, each of the fourth hinge arms having a fourth rotation shaft hole formed at an end thereof such that the fourth rotation shaft hole is aligned with the corresponding third rotation shaft hole, the second hinge unit further including a second hinge shaft coupling the third hinge arms and the fourth hinge arms at the third and fourth rotation shaft holes.   
     
     
         10 . The drum washing machine according to  claim 1 , wherein the first door is rotated about a first rotation shaft of the first hinge unit, the second door is rotated about a second rotation shaft of the second hinge unit, and the second hinge unit includes a hinge arm curvedly protruding from one side of the second door in a lateral direction thereof, the hinge arm having a curved guide groove in which the second rotation shaft is disposed such that the second rotation shaft is guided along the curved guide groove. 
     
     
         11 . The drum washing machine according to  claim 10 , wherein the curved guide groove has a regular radius of rotation about the first rotation shaft. 
     
     
         12 . The drum washing machine according to  claim 1 , wherein the second hinge unit comprises:
 a hinge bracket fixed to the water tub, the hinge bracket having a first link shaft;   a first link plate having one end rotatably coupled to the first link shaft and the other end coupled to a second link shaft;   a second link plate rotatably coupled to the second link shaft, the second link plate being curved toward the first link shaft, the second link plate having a hinge shaft provided at the end thereof; and   a hinge arm curvedly protruding from one side of the second door in a lateral direction thereof such that the hinge arm is guided along support planes provided at a top and a bottom of the second link plate, the hinge arm having a curved guide groove defined therein in which the hinge shaft is disposed.   
     
     
         13 . The drum washing machine according to  claim 12 , wherein the first link shaft is provided with a first torsion spring to elastically push the first link plate in a direction opposite to a direction in which the first link plate is rotated, and the second link shaft is provided with a second torsion spring to elastically push the second link plate in a direction identical to a direction in which the second link plate is rotated. 
     
     
         14 . The drum washing machine according to  claim 12 , wherein the support planes may each include a rib to prevent the hinge arm located on the support plane from being separated from the support plane. 
     
     
         15 . The drum washing machine according to  claim 12 , wherein each of the hinge arms is moved while the curved guide groove of the hinge arm is guided by the hinge shaft in the rotation direction to maintain a radius of rotation of the second door. 
     
     
         16 . The drum washing machine according to  claim 1 , wherein a center of the first door coincides with a center of the second door when the first door and the second door are simultaneously opened. 
     
     
         17 . A drum washing machine, comprising:
 a machine body having a first opening;   a water tub disposed in the machine body, the water tub having a second opening facing the first opening;   a rotary drum rotatably provided in the water tub to contain laundry;   a first door rotatably provided at the machine body to open and close the first opening; and   a second door rotatably provided at the tub to open and close the second opening, wherein   a distance between a first rotational track formed by an end of the first door and a second rotational track formed by an end of the second door is uniformly maintained upon opening and closing of the first door and the second door.   
     
     
         18 . The drum washing machine according to  claim 17 , wherein the first door is provided with a coupling unit to couple the first door and the second door such that the second door is simultaneously opened when the first door is opened. 
     
     
         19 . The drum washing machine according to  claim 18 , wherein the coupling unit includes a hook unit configured to be hooked by and released from a hook coupling part provided at the second door. 
     
     
         20 . The drum washing machine according to  claim 19 , wherein the coupling unit further includes an actuator to actuate the hook unit to be released from the hook coupling part and a hook holding lever to hold the hook unit released by the actuator. 
     
     
         21 . The drum washing machine according to  claim 20 , wherein the actuator releases the hook unit during an operation of the drum washing machine.