SERVING ROBOT

1 . A serving robot comprising:

a driving unit;

a vertical frame positioned above the driving unit and extending in a vertical direction;

a moving block having one side positioned on the vertical frame;

a tray mover configured to move the moving block in the vertical direction along the vertical frame; and

a tray plate seated on an opposite side of the moving block,

wherein the tray mover includes:

a rotation shaft positioned in the vertical frame and extending in the vertical direction;

a motor configured to provide a rotational force to the rotation shaft; and

a screw shaft allowing the rotation shaft to extend therethrough,

wherein the moving block is coupled to an outer circumferential surface of the screw shaft and moves in the vertical direction when the screw shaft rotates.

2 . The serving robot of claim 1 , wherein the rotation shaft includes a fixing portion positioned on one side of the screw shaft,

wherein the serving robot includes a coupling unit coupled to the fixing portion and rotatable together with the rotation shaft,

wherein the coupling unit moves in the vertical direction within a range of the fixing portion and is selectively coupled to the screw shaft,

wherein the screw shaft rotates together with the rotation shaft when being coupled to the coupling unit,

wherein the screw shaft does not rotate when being separated from the coupling unit.

3 . The serving robot of claim 2 , wherein the rotation shaft includes a fixing protrusion formed on an outer circumferential surface of a fixing portion where the coupling unit is coupled,

wherein the coupling unit includes a fixing hole wherein the fixing portion of the rotation shaft extends through, a fixing groove corresponding to the fixing protrusion.

4 . The serving robot of claim 2 , further comprising:

a first coupler located at one side of the screw shaft to face the coupling unit; and

a second coupler positioned on one surface of the coupling unit and coupled to or separated from the first coupler,

wherein when the first coupler and the second coupler are fastened to each other, the screw shaft rotates together with the rotation shaft.

5 . The serving robot of claim 4 , further comprising a coupling switch configured to move the coupling unit within the fixing portion such that the first coupler is detached from the second coupler.

6 . The serving robot of claim 5 , wherein the coupling switch further includes a contact roller contacting with the coupling unit.

7 . The serving robot of claim 6 , wherein the coupling unit has a disk shape including a switch groove defined in an outer circumferential surface thereof,

wherein the contact roller is inserted into the switch groove.

8 . The serving robot of claim 5 , wherein the coupling switch is exposed to the outside.

9 . The serving robot of claim 5 , wherein the coupling switch includes an actuator having a variable length, and a location of the coupling unit varies based on a change in the length of the actuator.

10 . The serving robot of claim 4 , wherein the second coupler is a magnet, and the first coupler includes a magnet having a polarity opposite to a polarity of the second coupler or a metal material.

11 . The serving robot of claim 4 , wherein the first coupler includes irregularities formed toward the coupling unit,

wherein the second coupler includes irregularities engaged with the irregularities of the first coupler.

12 . The serving robot of claim 2 , wherein the screw shaft includes an upper screw shaft and a lower screw shaft fitted with the rotation shaft and vertically arranged,

wherein the moving block and the tray plate are coupled to each of the upper screw shaft and the lower screw shaft.

13 . The serving robot of claim 1 , wherein the tray mover includes:

a connection gear positioned at an end of the rotation shaft; and

a timing belt coupled to the motor at one side and coupled to the connection gear at an opposite side to transmit the rotational force of the motor to the rotation shaft.

14 . The serving robot of claim 13 , wherein the vertical frame and the rotation shaft include a pair of vertical frames and a pair of rotation shafts positioned on left and right sides, respectively,

wherein the timing belt allows the pair of rotation shafts to be connected to the motor, and is connected to the respective connection gears of the pair of rotation shafts to transmit a driving force.

15 . The serving robot of claim 13 , wherein the moving block includes a pair of moving blocks to support both sides of the tray plate.