| CPC B60J 1/2033 (2013.01) [B60J 1/2052 (2013.01)] | 13 Claims |
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1. A shaft assembly, including:
a shaft connected to a blind sheet and performing rotational movement between a deployed position and a retracted position of the blind sheet;
a pair of end caps each being coupled to one side and the other side of the shaft to perform the rotational movement together with the shaft;
a gear unit connected to either one of the pair of end caps, the gear unit having a plurality of gears to interlock with the rotational movement of the shaft between the retracted position and the deployed position of the blind sheet and providing the shaft with a rotational movement force between the deployed position and the retracted position of the blind sheet; and
an elastic unit connected to any one of the plurality of gears of the gear unit and providing an elastic force so that the gear unit provides a rotational driving force to the shaft between the deployed position and the retracted position of the blind sheet,
wherein the gear unit includes:
a first gear connected to either one of the pair of end caps to interlock with the rotational movement of the shaft between the retracted position and the deployed position of the blind sheet and provide the shaft with the rotational movement force between the deployed position and the retracted position of the blind sheet;
a ring-shaped second gear disposed with the first gear at a center of the second gear and connected to the elastic unit to interlock with the rotational movement of the first gear and provide the rotational driving force to the first gear according to the elastic force provided from the elastic unit; and
a ring-shaped third gear disposed in a space between the first gear and the second gear and meshed with the first gear and the second gear, and performing the rotational movement so as to selectively transmit the rotational movement force provided from the first gear to the second gear and transmit the rotational movement force provided from the second gear to the first gear,
wherein the third gear transmits the rotational movement force according to the rotational movement of the first gear to the second gear between the retracted position and the deployed position of the blind sheet, and transmits the rotational movement force of the second gear, which performs the rotational movement by the elastic force provided from the elastic unit, to the first gear between the deployed position and the retracted position of the blind sheet,
wherein the shaft assembly further includes a casing that accommodates the gear unit and the elastic unit and is selectively coupled to and separated from either one of the pair of end caps, and
wherein the elastic unit includes a plate spring having an inner circumferential surface connected to the second gear and an outer circumferential surface connected to the casing and elastically deformed according to the rotational movement of the second gear and disposed between the casing and the second gear.
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