BACKGROUND

A dishwasher is a household appliance which uses detergent and water to wash food scraps off dirty dishes and cooking utensils.

Generally, a dishwasher includes a tub, a dish rack disposed in the tub to accommodate objects to be washed, a spray arm to spray wash water to the dish rack, a sump to store the wash water, and a supply flow passage to supply the wash water stored in the sump to the spray arm.

An idea related to the dishwasher is disclosed in Korean Patent Application Publication No. 10-2012-0126598, which is a related art document.

The dishwasher disclosed in the related art document has a structure for spraying wash water upward by a nozzle of a spray arm accommodated in a tub.

SUMMARY

According to one aspect, a dishwasher may include a tub configured to accommodate one or more items to be washed, a spray arm rotatably mounted to the tub and configured to spray water onto the one or more items to be washed, a sump disposed at a bottom surface of the tub and configured to store water and to supply stored water to the spray arm, a fixed gear unit fixed to the tub with gear teeth arranged along an outer circumferential surface of the fixed gear unit, a rotary gear unit rotatably mounted on the spray arm and configured to engage the gear teeth of the fixed gear unit, and a link member connected to the rotary gear unit and the spray arm, where the spray arm may include a main arm including a pair of arms, and a pair of auxiliary arms rotatably connected to the main arm, where the rotary gear unit may be configured to rotate based on engagement with the gear teeth of the fixed gear unit by rotation of the main arm, and where the link member may be configured to move by rotation of the rotary gear unit and rotate the pair of auxiliary arms.

Implementations according to this aspect may include one or more of the following features. For example, the dishwasher may include one or more power transfer units configured to extend from bottom surfaces of the pair of auxiliary arms and configured to be inserted into the link member, where one or more locking parts may be located at the link member, and where one or more power transfer units may be configured to be inserted into the one or more locking parts to transfer power to the power transfer units. The dishwasher may include a protrusion provided at an eccentric position from a center of rotation of the rotary gear unit and configured to be inserted into the link member, where the link member may include an insertion part, and where the protrusion may be configured to be inserted into the insertion part. The protrusion may be configured to move in a circular motion by the rotation of the rotary gear unit to move the link member. The dishwasher may include a guide protrusion inserted into the link member and configured to guide the link member to move back and forth in a linear motion, where a guide unit, into which the guide protrusion is inserted, may be located at a main extension part. The link member may include a main extension part disposed at lower portions of the pair of arms disposed at the main arm and one or more auxiliary extension parts disposed at lower portions of the pair of auxiliary arms. Each of the one or more auxiliary extension parts may be elastically deformed in a direction of a movement of the link member. The one or more auxiliary extension parts may be configured to be bent several times. One or more stoppers may be disposed at the auxiliary extension parts, and may be configured to limit rotational ranges of the pair of auxiliary arms. The gear teeth disposed at the fixed gear unit and the rotary gear unit may have asymmetrical shapes and may include a vertical portion and an inclined portion which extends from an upper end of the vertical portion at a predetermined angle. The spray arm may be configured to rotate by a repulsive force generated based on water being sprayed through spray holes in the main arm or each of the pair of the auxiliary arms.

According to another aspect, a dishwasher may include a sump configured to store water, an arm holder rotatably mounted on the sump, a spray arm connected to the arm holder and configured to spray the stored water from the sump, a fixed gear unit fixed to the sump and with gear teeth arranged along an outer circumferential surface of the fixed gear unit, a rotary gear unit rotatably mounted on the spray arm, and configured to rotate based on engagement with the gear teeth of the fixed gear unit, and a link member connected to the rotary gear unit and the spray arm, where the spray arm includes a main arm with a lower frame connected to the arm holder and an upper frame disposed at an upper side of the lower frame, and a pair of auxiliary arms rotatably disposed at both sides of the main arm and having a plurality of auxiliary spray holes, where inlets through which the water is introduced are formed at the lower frame, wherein a main flow passage is formed in the main arm and may be in fluid communication with the inlets, where a plurality of upper spray holes may be formed in the upper frame, and where the plurality of spray holes may be configured to spray the water in the main flow passage, where the plurality of upper spray holes may be radially disposed in the upper frame.

Implementations according to this aspect may include one or more of the following features. For example, the plurality of upper spray holes may be biased to one side of the main arm, and where the spray arm may be configured to rotate in one direction by a repulsive force generated when the water is sprayed through the main spray holes and the plurality of auxiliary spray holes may be biased to the other side of the main arm, and where the spray arm may be configured to rotate in an opposite direction by the repulsive force generated when the water is sprayed. A subset of the plurality of upper spray may be parallel to a direction in which the water is sprayed. A subset of the plurality of auxiliary spray holes may be parallel to the direction in which the water is sprayed. The dishwasher may include lower spray holes formed in a bottom surface of the lower frame, and configured to spray the water flowing in the main flow passage. A transfer flow passage may be formed in the main arm and may be in fluid communication with the inlets, where auxiliary flow passages may be formed in the auxiliary arms and may be in fluid communication with the transfer flow passage, and where the auxiliary flow passages may be in fluid communication with the auxiliary spray holes. The dishwasher may include a flow passage switching unit accommodated in the arm holder, and configured to selectively open and close the main flow passage and the transfer flow passage.

The flow passage switching unit may include a switching unit main body, an upper gear formed at the switching unit main body, and opening holes through which the water flows, where an upper gear engaging unit may be disposed at the bottom surface of the main arm, and may be configured to engage with the upper gear, where the flow passage switching unit may be configured to be engaged with the upper gear engaging unit when a flow amount of the water introduced into an arm holder chamber is increased, where one of the main flow passage and the transfer flow passage may be configured to communicate with the opening holes to have the water introduced and the other one of the main flow passage and the transfer flow passage may be closed by the switching unit main body when the upper gear is engaged with the upper gear engaging unit. A lower gear protruding downward may be disposed at the flow passage switching unit, and where a lower gear engaging unit may be disposed at a bottom surface of the arm holder chamber, and may be configured to be engaged with the lower gear. A rotary unit configured to provide a rotary force to the flow passage switching unit may be disposed at a bottom surface of the flow passage switching unit. The main arm may include a gear rotation shaft onto which the rotary gear unit is inserted, where the rotary gear unit may be configured to move vertically based on insertion into the gear rotation shaft so that the gear teeth of the fixed gear unit and the gear teeth of the rotary gear unit are selectively engaged with each other. The dishwasher may include an elastic unit disposed at the rotary gear unit, and configured to press the rotary gear unit toward the fixed gear unit. The gear teeth of the rotary gear unit may be configured to come in close contact with the gear teeth of the fixed gear unit by the hydraulic pressure of the water when the water is sprayed through the spray holes. The dishwasher may include a mounting unit at which the gear rotation shaft may be disposed and with a bottom surface portion configured to selectively make contact with an upper surface portion of the rotary gear unit, where the bottom surface portion of the mounting unit may be formed in a shape gradually inclined more upward from the gear rotation shaft toward the fixed gear unit. The spray holes may be disposed in the gear rotation shaft so that the wash water sprayed through the spray holes heads toward an inside of the rotary gear unit. The gear rotation shaft may be disposed at a place where a portion of a bottom surface of the main arm is recessed by a predetermined depth, where the gear rotation shaft may be inserted into the rotary gear unit and a rotation shaft accommodation unit may be disposed at the rotary gear unit, where at least a portion of the rotation shaft accommodation unit may be accommodated in the recessed place.

According to yet another aspect, a dishwasher may include a sump configured to store water, an arm holder rotatably mounted on the sump, a spray arm connected to the arm holder, and configured to rotate by a repulsive force generated when the stored water introduced from the sump is sprayed, a fixed gear unit fixed to the sump and with gear teeth arranged along an outer circumferential surface of the fixed gear unit, a rotary gear unit rotatably mounted on the spray arm, and configured to rotate based on engagement with the gear teeth of the fixed gear unit by rotation of the spray arm, and a link member connected to the rotary gear unit and the spray arm, where the spray arm includes a main arm including an arm holder coupling unit connected to the arm holder, a first arm extending to one side of the arm holder coupling unit, and a second arm extending to the other side of the arm holder coupling unit, and a first auxiliary arm and a second auxiliary arm disposed at the main arm in opposite directions from each other, and each of the first auxiliary arm and the second auxiliary arm is configured to rotate with respect to a longitudinal direction.

Implementations according to this aspect may include one or more of the following features. For example, the first auxiliary arm may be configured to form an acute angle with the first arm, and the second auxiliary arm may be configured to form an acute angle with the second arm. The link member may be configured to move back and forth by the rotary gear unit when the spray arm rotates, and the back and forth movements of the link member may be converted to rotary movements of the auxiliary arms. A plurality of auxiliary spray holes may be formed in the first auxiliary arm and the second auxiliary arm, where at least one of the plurality of auxiliary spray holes formed in the first auxiliary arm and at least one of the plurality of auxiliary spray holes formed in the second auxiliary arm are parallel to a direction in which the water is sprayed.

