Cord retractor and window covering having same

A cord retractor for a window covering, comprising:

• a housing, comprising a bottom plate and a shaft situated on a first side of the bottom plate;
• a driving wheel, situated on the first side of the bottom plate;
• a spring, received in the housing and comprising a first end coupled with the driving wheel, wherein the spring is wound on the driving wheel or unwound from the driving wheel according to a rotating direction of the driving wheel;
• a reeling wheel, situated on the first side of the bottom plate and coupled with the driving wheel for rotating with the driving wheel;
• a friction member being a single one-piece body in a closed loop shape surrounding the shaft;
• a unidirectional transmission mechanism coupled with the friction member and the reeling wheel and operated in one of a first operation mode and a second operation mode according to a rotating direction of the reeling wheel;
• wherein when the reeling wheel rotates in a first direction, the unidirectional transmission mechanism is driven to operate in the first operation mode with the friction member to generate a frictional force for providing substantially constant resistance to rotation of the reeling wheel;
• and
• wherein when the reeling wheel rotates in a second direction opposite to the first direction, the unidirectional transmission mechanism is driven to operate in the second operation mode and restricts the friction member from providing resistance to the rotation of the reeling wheel.

A window covering, comprising:

• an upper rail;
• one or more covering materials, provided below the upper rail;
• a bottom rail, provided below the one or more covering materials;
• a lift cord coupled between the upper rail and the bottom rail;
• a cord retractor for receiving or releasing the lift cord for respectively moving the bottom rail towards or away from the upper rail, wherein the cord retractor comprises:
• a housing, comprising a bottom plate and a shaft situated on a first side of the bottom plate;
• a driving wheel, situated on the first side of the bottom plate;
• a spring, received in the housing and comprising a first end coupled with the driving wheel, wherein the spring is wound on the driving wheel or unwound from the driving wheel according to a rotating direction of the driving wheel;
• a reeling wheel, situated on the first side of the bottom plate and coupled with the driving wheel for rotating with the driving wheel;
• a friction member in a closed loop shape and surrounding the shaft;
• a first limiting member, situated outside the friction member and comprising an arm;
• and
• a second limiting member, situated outside the first limiting member and comprising a plurality of ratchets for engaging with the arm of the first limiting member, wherein the second limiting member is driven by the reeling wheel to rotate with the reeling wheel;
• wherein when the reeling wheel rotates in a first direction, the second limiting member is driven to rotate in a locking direction with respect to the first limiting member, thereby making the arm of the first limiting member engaged between the two neighboring ratchets of the plurality of ratchets of the second limiting member, after which the first limiting member rotates together with the second limiting member, and one of a first frictional force and a second frictional force is generated for providing substantially constant resistance to rotation of the reeling wheel;
• wherein the first frictional force is generated between the first limiting member and the friction member, as the first limiting member rotates with respect to the friction member;
• wherein the second frictional force is generated between the friction member and the shaft, as the friction member is driven by the first limiting member to rotate with respect to the shaft;
• and
• wherein when the reeling wheel rotates in a second direction opposite to the first direction, the second limiting member is driven to rotate in an unlocking direction with respect to the first limiting member, and the arm of the first limiting member skids over the ratchets of the second limiting member, so that the first limiting member is not driven to rotate together with the second limiting member, and the friction member does not rotate with respect to the shaft or the first limiting member, such that the friction member does not provide resistance to the rotation of the reeling wheel while the reeling wheel rotates in the second direction.