Patent Publication Number: US-11035438-B2

Title: Transmission mechanism, follow focus, follow focus actuator, and imaging device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of application Ser. No. 15/958,692, filed Apr. 20, 2018, which is a continuation of International Application No. PCT/CN2015/092466, filed on Oct. 21, 2015, the entire contents of both of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a transmission mechanism, a follow focus, a follow focus actuator and an imaging device. 
     BACKGROUND OF THE DISCLOSURE 
     A follow focus can comprise a motor and an output gear coupled to the motor. The output gear can be sleeved on a rotating shaft of the motor and coupled to the rotating shaft by a fastening screw, such that a torque can be transmitted from the motor to the output gear through the rotating shaft. An end of the fastening screw can pass through the output gear along a radial direction of the rotating shaft and can be then mounted in the rotating shaft. An assembly and disassembly of the follow focus can be inconvenient as specific tools are required. 
     SUMMARY OF THE DISCLOSURE 
     There is a need for a transmission mechanism, a follow focus, a follow focus actuator and an imaging device that can be conveniently assembled and disassembled. 
     An aspect of the present disclosure provides a transmission mechanism for transmitting a power of a power device, the transmission mechanism comprising an adaptor and an output member, the adaptor being connected to the power device and transmitting the power of the power device to the output member, the output member outputting the power, the adaptor driving a coaxial rotation of the output member by a rotation of the adaptor to output the power. The adaptor and the output member can be engaged with each other through a relative movement along an axial direction. The engagement can limit a relative rotation between the adaptor and the output member. The transmission mechanism can further comprise a locking member rotatably provided on the output member, the locking member passing through the output member along an axial direction of the output member and comprising an operating portion. The operating portion can be operable to connect the locking member with the adaptor or disconnect the locking member from the adaptor. The relative movement between the adaptor and the output member along the axial direction can be limited when the locking member are connected to the adaptor. 
     In some embodiments, the adaptor can comprise an engaging portion. The output member can comprise a holding portion. The engaging portion can abut against the holding portion or release from the holding portion to bring the transmission mechanism into an assembled state or a disassembled state. 
     In some embodiments, the output member can comprise a holding member and an output gear connected to the holding member. The holding member can abut against the adaptor or release from the adaptor to bring the transmission mechanism into the assembled state or the disassembled state. The output member can output the power to a load through the output gear. 
     In some embodiments, the holding portion can be formed on the holding member. 
     In some embodiments, the engaging portion can comprise a plurality of protruding blocks, a slot being formed between two adjacent protruding blocks. The holding portion can comprise a plurality of protrusions corresponding to the slots. The protrusions can engage into or disengage from the corresponding slots to cause the engaging portion abut against the holding portion or release from the holding portion. 
     In some embodiments, the adaptor can comprise a transmission shaft. The engaging portion can be provided at an end portion of the transmission shaft. The plurality of protruding blocks can be arranged along a circumference of an end face of the transmission shaft with an interval therebetween. 
     In some embodiments, two engaging portions can be respectively provided at two ends of the transmission shaft. 
     In some embodiments, the adaptor can further comprise a transmission wheel for connecting the power device. A mounting portion can be formed on the transmission shaft at which the transmission wheel can be provided. The mounting portion can prevent a movement of the transmission wheel relative to the transmission shaft along a circumferential direction and an axial direction of the transmission shaft. 
     In some embodiments, four mounting portions can be evenly arranged along the circumferential direction of the transmission shaft. 
     In some embodiments, the transmission wheel can comprise a plurality of gear teeth through which the transmission wheel can be meshed with the power device. 
     In some embodiments, an angle between a lengthwise direction of the gear teeth and an axial direction of a central axis of the transmission wheel can be an acute angle. 
     In some embodiments, the locking member can pass through the output gear and the holding member and be threadedly connected to or disconnected from the adaptor to cause the holding member abut against the adaptor or release from the adaptor. 
     In some embodiments, the locking member can comprise a connecting rod, the connecting rod being threadedly connected to or disconnected from the transmission shaft to cause the holding member abut against the adaptor or release from the adaptor. 
     In some embodiments, the transmission shaft can be provided with an accommodating hole. A collar can extend from a position at a middle of an inner wall of the accommodating hole, and the adaptor can be threadedly connected to or disconnected from the connecting rod through the collar. 
     In some embodiments, a thread can be formed on a surface of the collar facing a central axis of the transmission shaft. 
     In some embodiments, the holding member can be provided with a via hole, and the output gear can be provided with a through hole and a groove in communication with the through hole. The holding member can be mounted within the groove. The locking member can protrude from the holding member upon passing through the through hole and the via hole. 
     In some embodiments, the plurality of protrusions can be arranged along a circumference of the via hole with an interval therebetween. 
     In some embodiments, the holding member can be provided with a guide hole. A rib can be fixed on a bottom surface of the groove facing the holding member. The rib can be inserted into the guide hole to guide a connection between the output gear and the holding member. 
     In some embodiments, the output gear can comprise a meshing portion through which the output gear can drive a rotation of the load. 
     Another aspect of the present disclosure provides a follow focus, the follow focus comprising a casing, a power device and a transmission mechanism connected to the casing for transmitting a power of the power device, the transmission mechanism comprising an adaptor and an output member, the adaptor being connected to the power device and transmitting the power of the power device to the output member, the output member outputting the power, the adaptor driving a coaxial rotation of the output member by a rotation of the adaptor to output the power. The adaptor and the output member can be engaged with each other through a relative movement along an axial direction. The engagement can limit a relative rotation between the adaptor and the output member. The transmission mechanism can further comprise a locking member rotatably provided on the output member, the locking member passing through the output member along an axial direction of the output member and comprising an operating portion. The operating portion can be operable to connect the locking member with the adaptor or disconnect the locking member from the adaptor. The relative movement between the adaptor and the output member along the axial direction can be limited when the locking member are connected to the adaptor. 
     In some embodiments, the power device can be provided within the casing. The transmission mechanism can be provided on the casing through the adaptor. The transmission mechanism can be connected to the power device through the adaptor. The power device can drive a rotation of the output member through the adaptor. 
     In some embodiments, a clearing slot can be provided on the casing for accommodating the output member upon assembling the follow focus. 
     In some embodiments, two clearing slots can be provided facing away from each other. 
     In some embodiments, the casing can be provided with a housing hole in communication with the clearing slot. The adaptor can be mounted within the housing hole. 
     In some embodiments, a receiving cavity in communication with the housing hole can be formed in the casing. The power device can be received in the receiving cavity. 
     In some embodiments, the power device can comprise an output shaft meshed with the adaptor to drive the rotation of the adaptor. 
     In some embodiments, the follow focus can further comprise a latching member connected to the casing. The follow focus can be detachably connected to a carrier through the latching member. 
     In some embodiments, the latching member can comprise a knob movably connected to the casing, a stationary portion connected to the casing and a movable portion rotatably connected to the stationary portion. The knob can be rotatable relative to the casing to bring the latching member into a locked state or a disassembled state. 
     In some embodiments, the movable portion can be connected to the knob. The knob can drive a rotation of the movable portion relative to the stationary portion. 
     In some embodiments, a receiving hole for receiving the carrier can be formed by the movable portion and the stationary portion when the latching member is in the locked state. 
     In some embodiments, the adaptor can comprise an engaging portion, and the output member can comprise a holding portion. The engaging portion can abut against the holding portion or release from the holding portion to bring the transmission mechanism into an assembled state or a disassembled state. 
     In some embodiments, the output member can comprise a holding member and an output gear connected to the holding member. The holding member can abut against the adaptor or release from the adaptor to bring the transmission mechanism into the assembled state or the disassembled state. The output member can output the power to a load through the output gear. 
     In some embodiments, the holding portion can be formed on the holding member. 
     In some embodiments, the engaging portion can comprise a plurality of protruding blocks, a slot being formed between two adjacent protruding blocks. The holding portion can comprise a plurality of protrusions corresponding to the slots. The protrusions can engage into or disengage from the corresponding slots to cause the engaging portion abut against the holding portion or release from the holding portion. 
     In some embodiments, the adaptor can comprise a transmission shaft. The engaging portion can be provided at an end portion of the transmission shaft. The plurality of protruding blocks can be arranged along a circumference of an end face of the transmission shaft with an interval therebetween. 
     In some embodiments, two engaging portions can be respectively provided at two ends of the transmission shaft. 
     In some embodiments, the adaptor can further comprise a transmission wheel for connecting the power device. A mounting portion can be formed on the transmission shaft at which the transmission wheel can be provided. The mounting portion can prevent a movement of the transmission wheel relative to the transmission shaft along a circumferential direction and an axial direction of the transmission shaft. 
     In some embodiments, four mounting portions can be evenly arranged along the circumferential direction of the transmission shaft. 
     In some embodiments, the transmission wheel can comprise a plurality of gear teeth through which the transmission wheel can be meshed with the power device. 
     In some embodiments, an angle between a lengthwise direction of the gear teeth and an axial direction of a central axis of the transmission wheel can be an acute angle. 
     In some embodiments, the locking member can pass through the output gear and the holding member and be threadedly connected to or disconnected from the adaptor to cause the holding member abut against the adaptor or release from the adaptor. 
     In some embodiments, the locking member can comprise a connecting rod, the connecting rod being threadedly connected to or disconnected from the transmission shaft to cause the holding member abut against the adaptor or release from the adaptor. 
     In some embodiments, the transmission shaft can be provided with an accommodating hole. A collar can extend from a position at a middle of an inner wall of the accommodating hole. The adaptor can be threadedly connected to or disconnected from the connecting rod through the collar. 
     In some embodiments, a thread can be formed on a surface of the collar facing a central axis of the transmission shaft. 
     In some embodiments, the holding member can be provided with a via hole, and the output gear can be provided with a through hole and a groove in communication with the through hole. The holding member can be mounted within the groove. The locking member can protrude from the holding member upon passing through the through hole and the via hole. 
     In some embodiments, the plurality of protrusions can be arranged along a circumference of the via hole. 
     In some embodiments, the holding member can be provided with a guide hole. A rib can be fixed on a bottom surface of the groove facing the holding member. The rib can be inserted into the guide hole to guide a connection between the output gear and the holding member. 
     In some embodiments, the output gear can comprise a meshing portion through which the output gear can drive a rotation of the load. 
     In some embodiments, two output members can be provided each of which being detachably connected to the adaptor through the locking member. The adaptor can drive a coaxial rotation of the two output members. 
     Another aspect of the present disclosure provides an imaging device, the imaging device comprising a gimbal, an imaging element provided on the gimbal and a follow focus provided on the gimbal, the follow focus comprising a casing, a power device and a transmission mechanism connected to the casing for transmitting a power of the power device, the transmission mechanism comprising an adaptor and an output member, the adaptor being connected to the power device and transmitting the power of the power device to the output member, the output member outputting the power to the imaging element, the adaptor driving a coaxial rotation of the output member by a rotation of the adaptor to output the power. The adaptor and the output member can be engaged with each other through a relative movement along an axial direction. The engagement can limit a relative rotation between the adaptor and the output member. The transmission mechanism can further comprise a locking member rotatably provided on the output member, the locking member passing through the output member along an axial direction of the output member and comprising an operating portion. The operating portion can be operable to connect the locking member with the adaptor or disconnect the locking member from the adaptor. The relative movement between the adaptor and the output member along the axial direction can be limited when the locking member are connected to the adaptor. 
     In some embodiments, the gimbal can comprise a carrier, a carrying platform and a mounting rod provided on the carrier, a first operating handle and a second operating handle connected to the mounting rod, and a carrying rod connected to the carrying platform. The imaging element can be provided on the carrying platform. The follow focus can be connected to the carrying rod. 
     In some embodiments, the follow focus can comprise a gear ring. The gear ring can be sleeved on a lens ring of the imaging element. The gear ring can be meshed with the output member. The power device can drive a rotation of the gear ring through the adaptor to effect a focusing of the imaging element. Or the gear ring can be sleeved on an aperture ring of the imaging element and meshed with the output member. The power device can drive a rotation of the gear ring through the adaptor to effect an aperture adjustment of the imaging element. 
     In some embodiments, the power device can be provided within the casing. The transmission mechanism can be provided on the casing through the adaptor. The transmission mechanism can be connected to the power device through the adaptor. The power device can drive a rotation of the output member through the adaptor. 
     In some embodiments, a clearing slot can be provided on the casing for accommodating the output member upon assembling the follow focus. 
     In some embodiments, two clearing slots can be provided facing away from each other. 
     In some embodiments, the casing can be provided with a housing hole in communication with the clearing slot. The adaptor can be mounted within the housing hole. 
     In some embodiments, a receiving cavity in communication with the housing hole can be formed in the casing. The power device can be received in the receiving cavity. 
     In some embodiments, the power device can comprise an output shaft meshed with the adaptor to drive the rotation of the adaptor. 
     In some embodiments, the follow focus can further comprise a latching member connected to the casing. The follow focus can be detachably connected to the gimbal through the latching member. 
     In some embodiments, the latching member can comprise a knob movably connected to the casing, a stationary portion connected to the casing and a movable portion rotatably connected to the stationary portion. The knob can be rotatable relative to the casing to bring the latching member into a locked state or a disassembled state. 
     In some embodiments, the movable portion can be connected to the knob. The knob can drive a rotation of the movable portion relative to the stationary portion. 
     In some embodiments, a receiving hole for receiving the carrier can be formed by the movable portion and the stationary portion when the latching member is in the locked state. 
     In some embodiments, the adaptor can comprise an engaging portion, and the output member can comprise a holding portion. The engaging portion can abut against the holding portion or release from the holding portion to bring the transmission mechanism into an assembled state or a disassembled state. 
     In some embodiments, the output member can comprise a holding member and an output gear connected to the holding member. The holding member can abut against the adaptor or release from the adaptor to bring the transmission mechanism into the assembled state or the disassembled state. The output member can output the power to the imaging element through the output gear. 
     In some embodiments, the holding portion can be formed on the holding member. 
     In some embodiments, the engaging portion can comprise a plurality of protruding blocks, a slot being formed between two adjacent protruding blocks. The holding portion can comprise a plurality of protrusions corresponding to the slots. The protrusions can engage into or disengage from the corresponding slots to cause the engaging portion abut against the holding portion or release from the holding portion. 
     In some embodiments, the adaptor can comprise a transmission shaft. The engaging portion can be provided at an end portion of the transmission shaft. The plurality of protruding blocks can be arranged along a circumference of an end face of the transmission shaft with an interval therebetween. 
     In some embodiments, two engaging portions can be respectively provided at two ends of the transmission shaft. 
     In some embodiments, the adaptor can further comprise a transmission wheel for connecting the power device. A mounting portion can be formed on the transmission shaft at which the transmission wheel can be provided. The mounting portion can prevent a movement of the transmission wheel relative to the transmission shaft along a circumferential direction and an axial direction of the transmission shaft. 
     In some embodiments, four mounting portions can be evenly arranged along the circumferential direction of the transmission shaft. 
     In some embodiments, the transmission wheel can comprise a plurality of gear teeth through which the transmission wheel can be meshed with the power device. 
     In some embodiments, an angle between a lengthwise direction of the gear teeth and an axial direction of a central axis of the transmission wheel can be an acute angle. 
     In some embodiments, the locking member can pass through the output gear and the holding member and be threadedly connected to or disconnected from the adaptor to cause the holding member abut against the adaptor or release from the adaptor. 
     In some embodiments, the locking member can comprise a connecting rod, the connecting rod being threadedly connected to or disconnected from the transmission shaft to cause the holding member abut against the adaptor or release from the adaptor. 
     In some embodiments, the transmission shaft can be provided with an accommodating hole. A collar can extend from a position at a middle of an inner wall of the accommodating hole. The adaptor can be threadedly connected to or disconnected from the connecting rod through the collar. 
     In some embodiments, a thread can be formed on a surface of the collar facing a central axis of the transmission shaft. 
     In some embodiments, the holding member can be provided with a via hole, and the output gear can be provided with a through hole and a groove in communication with the through hole. The holding member can be mounted within the groove. The locking member can protrude from the holding member upon passing through the through hole and the via hole. 
     In some embodiments, the plurality of protrusions can be arranged along a circumference of the via hole. 
     In some embodiments, the holding member can be provided with a guide hole. A rib can be fixed on a bottom surface of the groove facing the holding member. The rib can be inserted into the guide hole to guide a connection between the output gear and the holding member. 
     In some embodiments, the output gear can comprise a meshing portion through which the output gear can drive a rotation of the imaging element. 
     In some embodiments, two output members can be provided each of which being detachably connected to the adaptor through the locking member. The adaptor can drive a coaxial rotation of the two output members. 
     Another aspect of the present disclosure provides a transmission mechanism for transmitting a power of a power device, the transmission mechanism comprising an output member and a worm wheel shaft connected to the power device to transmit the power of the power device to the output member. The output member can output the power. The worm wheel shaft can drive a coaxial rotation of the output member by a rotation of the worm wheel shaft to output the power. The worm wheel shaft and the output member can be engaged with each other through a relative movement along an axial direction. The engagement can limit a relative rotation between the worm wheel shaft and the output member. 
     In some embodiments, the transmission mechanism can further comprise a locking member rotatably provided on the output member. The locking member can pass through the output member along an axial direction of the output member. An operating portion provided on the locking member can be operated to connect the locking member with the worm wheel shaft or disconnect locking member from the worm wheel shaft. The relative movement between the worm wheel shaft and the output member can be limited when the locking member is connected with the worm wheel shaft. 
     In some embodiments, the worm wheel shaft can comprise an engaging portion, the output member can comprise a holding portion, and the engaging portion and the holding portion can abut against or release from each other to bring the transmission mechanism into an assembled state or a disassembled state. 
     In some embodiments, the output member can comprise a holding member and an output gear connected to the holding member. The holding member can abut against the worm wheel shaft or release from the worm wheel shaft to bring the transmission mechanism into the assembled state or the disassembled state. The output member can output the power to a load through the output gear. 
     In some embodiments, the holding portion can be formed on the holding member. 
     In some embodiments, the engaging portion can comprise a plurality of protruding blocks, a slot being formed between two adjacent protruding blocks. The holding portion can comprise a plurality of protrusions corresponding to the slots. The protrusions can engage into or disengage from the corresponding slots to cause the engaging portion abut against the holding portion or release from the holding portion. 
     In some embodiments, the worm wheel shaft can comprise a transmission shaft. The engaging portion can be provided at an end portion of the transmission shaft. The plurality of protruding blocks can be arranged along a circumference of an end face of the transmission shaft with an interval therebetween. 
     In some embodiments, two engaging portions can be respectively provided at two ends of the transmission shaft. 
     In some embodiments, the locking member can pass through the output gear and the holding member and be threadedly connected to or disconnected from the worm wheel shaft to abut the holding member against the worm wheel shaft to or release the holding member from the worm wheel. 
     In some embodiments, the locking member can comprise a connecting rod, the connecting rod being threadedly connected to or disconnected from the transmission shaft to cause the holding member abut against the worm wheel shaft or release from the worm wheel shaft. 
     In some embodiments, the transmission shaft can be provided with an accommodating hole. A collar can extend from a position at a middle of an inner wall of the accommodating hole, and the worm wheel shaft can be threadedly connected to or disconnected from the connecting rod through the collar. 
     In some embodiments, a thread can be formed on a surface of the collar facing a central axis of the transmission shaft. 
     In some embodiments, the holding member can be provided with a via hole, and the output gear can be provided with a through hole and a groove in communication with the through hole. The holding member can be mounted within the groove. The locking member can protrude from the holding member upon passing through the through hole and the via hole. 
     In some embodiments, the plurality of protrusions can be arranged along a circumference of the via hole with an interval therebetween. 
     In some embodiments, the holding member can be provided with a guide hole. A rib can be fixed on a bottom surface of the groove facing the holding member. The rib can be inserted into the guide hole to guide a connection between the output gear and the holding member. 
     In some embodiments, the output gear can comprise a meshing portion through which the output gear can drive a rotation of the load. 
     Another aspect of the present disclosure provides a follow focus actuator, the follow focus actuator comprising a casing, a power device and a transmission mechanism connected to the casing for transmitting a power of the power device, the transmission mechanism comprising an output member and a worm wheel shaft connected to the power device to transmit the power of the power device to the output member. The output member can output the power. The worm wheel shaft can drive a coaxial rotation of the output member by a rotation of the worm wheel shaft to output the power. The worm wheel shaft and the output member can be engaged with each other through a relative movement along an axial direction. The engagement can limit a relative rotation between the worm wheel shaft and the output member. 
     In some embodiments, the transmission mechanism can further comprise a locking member rotatably provided on the output member. The locking member can pass through the output member along an axial direction of the output member. An operating portion provided on the locking member can be operated to connect the locking member with the worm wheel shaft or disconnect locking member from the worm wheel shaft. The relative movement between the worm wheel shaft and the output member can be limited when the locking member is connected with the worm wheel shaft. 
     In some embodiments, the power device can be provided within the casing. The transmission mechanism can be provided on the casing through the worm wheel shaft. The transmission mechanism can be connected to the power device through the worm wheel shaft. The power device can drive a rotation of the output member through the worm wheel shaft. 
     In some embodiments, a clearing slot can be provided on the casing for accommodating the output member upon assembling the follow focus actuator. 
     In some embodiments, two clearing slots can be provided facing away from each other. 
     In some embodiments, the casing can be provided with a housing hole in communication with the clearing slot. The worm wheel shaft can be mounted within the housing hole. 
     In some embodiments, a receiving cavity in communication with the housing hole can be formed in the casing. The power device can be received in the receiving cavity. 
     In some embodiments, the power device can comprise an output shaft meshed with the worm wheel shaft to drive the rotation of the worm wheel shaft. 
     In some embodiments, the follow focus actuator can further comprise a latching member connected to the casing. The follow focus actuator can be detachably connected to a carrier through the latching member. 
     In some embodiments, the latching member can comprise a knob movably connected to the casing, a stationary portion connected to the casing and a movable portion rotatably connected to the stationary portion. The knob can be rotatable relative to the casing to bring the latching member into a locked state or a disassembled state. 
     In some embodiments, the movable portion can be connected to the knob. The knob can drive a rotation of the movable portion relative to the stationary portion. 
     In some embodiments, a receiving hole for receiving the carrier can be formed by the movable portion and the stationary portion when the latching member is in the locked state. 
     In some embodiments, the worm wheel shaft can comprise an engaging portion, and the output member can comprise a holding portion. The engaging portion can abut against the holding portion or release from clearing slot to bring the transmission mechanism into an assembled state or a disassembled state. 
     In some embodiments, the output member can comprise a holding member and an output gear connected to the holding member. The holding member can abut against the worm wheel shaft or release from the worm wheel shaft to bring the transmission mechanism into the assembled state or the disassembled state. The output member can output the power to a load through the output gear. 
     In some embodiments, the holding portion can be formed on the holding member. 
     In some embodiments, the engaging portion can comprise a plurality of protruding blocks, a slot being formed between two adjacent protruding blocks. The holding portion can comprise a plurality of protrusions corresponding to the slots. The protrusions can engage into or disengage from the corresponding slots to cause the engaging portion abut against the holding portion or release from the holding portion. 
     In some embodiments, the worm wheel shaft can comprise a transmission shaft. The engaging portion can be provided at an end portion of the transmission shaft. The plurality of protruding blocks cam be arranged along a circumference of an end face of the transmission shaft with an interval therebetween. 
     In some embodiments, two engaging portions can be respectively provided at two ends of the transmission shaft. 
     In some embodiments, the locking member can pass through the output gear and the holding member and be threadedly connected to or disconnected from the worm wheel shaft to abut the holding member against the worm wheel shaft to or release the holding member from the worm wheel. 
     In some embodiments, the locking member can comprise a connecting rod, the connecting rod being threadedly connected to or disconnected from the transmission shaft to cause the holding member abut against the worm wheel shaft or release from the worm wheel shaft. 
     In some embodiments, the transmission shaft can be provided with an accommodating hole. A collar can extend from a position at a middle of an inner wall of the accommodating hole, and the worm wheel shaft can be threadedly connected to or disconnected from the connecting rod through the collar. 
     In some embodiments, a thread can be formed on a surface of the collar facing a central axis of the transmission shaft. 
     In some embodiments, the holding member can be provided with a via hole, and the output gear can be provided with a through hole and a groove in communication with the through hole. The holding member can be mounted within the groove. The locking member can protrude from the holding member upon passing through the through hole and the via hole. 
     In some embodiments, the plurality of protrusions can be arranged along a circumference of the via hole with an interval therebetween. 
     In some embodiments, the holding member can be provided with a guide hole. A rib can be fixed on a bottom surface of the groove facing the holding member. The rib can be inserted into the guide hole to guide a connection between the output gear and the holding member. 
     In some embodiments, the output gear can comprise a meshing portion through which the output gear can drive a rotation of the load. 
     In some embodiments, two output members can be provided each of which being detachably connected to the worm wheel shaft through the locking member. The worm wheel shaft can drive a coaxial rotation of the two output members. 
     Another aspect of the present disclosure provides an imaging device, the imaging device comprising a gimbal, an imaging element provided on the gimbal and a follow focus actuator provided on the gimbal, the follow focus actuator comprising a casing and a power device, and further comprising a transmission mechanism connected to the casing for transmitting a power of the power device, the transmission mechanism comprising an output member and a worm wheel shaft connected to the power device to transmit the power of the power device to the output member. The output member can output the power to the imaging element. The worm wheel shaft can drive a coaxial rotation of the output member by a rotation of the worm wheel shaft to output the power. The worm wheel shaft and the output member can be engaged with each other through a relative movement along an axial direction. The engagement can limit a relative rotation between the worm wheel shaft and the output member. 
     In some embodiments, the transmission mechanism can further comprise a locking member rotatably provided on the output member. The locking member can pass through the output member along an axial direction of the output member. An operating portion provided on the locking member can be operated to connect the locking member with the worm wheel shaft or disconnect locking member from the worm wheel shaft. The relative movement between the worm wheel shaft and the output member can be limited when the locking member is connected with the worm wheel shaft. 
     In some embodiments, the gimbal can comprise a carrier, a carrying platform and a mounting rod provided on the carrier, a first operating handle and a second operating handle connected to the mounting rod, and a carrying rod connected to the carrying platform. The imaging element can be provided on the carrying platform. The follow focus actuator can be connected to the carrying rod. 
     In some embodiments, the follow focus actuator can comprise a gear ring. The gear ring can be sleeved on a lens ring of the imaging element. The gear ring can be meshed with the output member. The power device can drive a rotation of the gear ring through the adaptor to effect a focusing of the imaging element. Or, the gear ring can be sleeved on an aperture ring of the imaging element and meshed with the output member, and the power device can drive a rotation of the gear ring through the adaptor to effect an aperture adjustment of the imaging element. 
     In some embodiments, the power device can be provided within the casing. The transmission mechanism can be provided on the casing through the worm wheel shaft. The transmission mechanism can be connected to the power device through the worm wheel shaft. The power device can drive a rotation of the output member through the worm wheel shaft. 
     In some embodiments, a clearing slot can be provided on the casing for accommodating the output member upon assembling the follow focus actuator. 
     In some embodiments, two clearing slots can be provided facing away from each other. 
     In some embodiments, the casing can be provided with a housing hole in communication with the clearing slot. The worm wheel shaft can be mounted within the housing hole. 
     In some embodiments, a receiving cavity in communication with the housing hole can be formed in the casing. The power device can be received in the receiving cavity. 
     In some embodiments, the power device can comprise an output shaft meshed with the worm wheel shaft to drive the rotation of the worm wheel shaft. 
     In some embodiments, the follow focus actuator can further comprise a latching member connected to the casing. The follow focus actuator can be detachably connected to the gimbal through the latching member. 
     In some embodiments, the latching member can comprise a knob movably connected to the casing, a stationary portion connected to the casing and a movable portion rotatably connected to the stationary portion. The knob can be rotatable relative to the casing to bring the latching member into a locked state or a disassembled state. 
     In some embodiments, the movable portion can be connected to the knob, and the knob can drive a rotation of the movable portion relative to the stationary portion. 
     In some embodiments, a receiving hole for receiving the carrier can be formed by the movable portion and the stationary portion when the latching member is in the locked state. 
     In some embodiments, the worm wheel shaft can comprise an engaging portion, and the output member can comprise a holding portion. The engaging portion can abut against the holding portion or release from the holding portion to bring the transmission mechanism into an assembled state or a disassembled state. 
     In some embodiments, the output member can comprise a holding member and an output gear connected to the holding member. The holding member can abut against the worm wheel shaft or release from the worm wheel shaft to bring the transmission mechanism into the assembled state or the disassembled state. The output member can output the power to the imaging element through the output gear. 
     In some embodiments, the holding portion can be formed on the holding member. 
     In some embodiments, the engaging portion can comprise a plurality of protruding blocks, a slot being formed between two adjacent protruding blocks. The holding portion can comprise a plurality of protrusions corresponding to the slots. The protrusions can engage into or disengage from the corresponding slots to cause the engaging portion abut against the holding portion or release from the holding portion. 
     In some embodiments, the worm wheel shaft can comprise a transmission shaft. The engaging portion can be provided at an end portion of the transmission shaft. The plurality of protruding blocks can be arranged along a circumference of an end face of the transmission shaft with an interval therebetween. 
     In some embodiments, two engaging portions can be respectively provided at two ends of the transmission shaft. 
     In some embodiments, the locking member can pass through the output gear and the holding member and be threadedly connected to or disconnected from the worm wheel shaft to abut the holding member against the worm wheel shaft to or release the holding member from the worm wheel. 
     In some embodiments, the locking member can comprise a connecting rod, the connecting rod being threadedly connected to or disconnected from the transmission shaft to cause the holding member abut against the worm wheel shaft or release from the worm wheel shaft. 
     In some embodiments, the transmission shaft can be provided with an accommodating hole. A collar can extend from a position at a middle of an inner wall of the accommodating hole, and the worm wheel shaft can be threadedly connected to or disconnected from the connecting rod through the collar. 
     In some embodiments, a thread can be formed on a surface of the collar facing a central axis of the transmission shaft. 
     In some embodiments, the holding member can be provided with a via hole, and the output gear can be provided with a through hole and a groove in communication with the through hole. The holding member can be mounted within the groove. The locking member can protrude from the holding member upon passing through the through hole and the via hole. 
     In some embodiments, the plurality of protrusions can be arranged along a circumference of the via hole with an interval therebetween. 
     In some embodiments, the holding member can be provided with a guide hole. A rib can be fixed on a bottom surface of the groove facing the holding member. The rib can be inserted into the guide hole to guide a connection between the output gear and the holding member. 
     In some embodiments, the output gear can comprise a meshing portion through which the output gear can drive a rotation of the imaging element. 
     In some embodiments, two output members can be provided each of which being detachably connected to the worm wheel shaft through the locking member. The worm wheel shaft can drive a coaxial rotation of the two output members. 
     In some embodiments, the gimbal can further comprise a control assembly through which the imaging element can be provided on the gimbal. 
     In some embodiments, the control assembly can comprise a measuring part and a controller, the measuring part being configured to obtain a status information of the imaging element, the controller being configured to calculate an attitude information of the imaging element based upon the status information and output one or more motor signals based upon the attitude information. The gimbal can further comprise a motor assembly configured to directly drive the gimbal based upon the one or more motor signals to effect a rotation of the imaging element about at least one of a pitch axis, a roll axis or a yaw axis of the gimbal. 
     In some embodiments, the measuring part can comprise an inertial measurement unit (IMU). 
     With the transmission mechanism, the follow focus, the follow focus actuator and the imaging device of the disclosure, the adaptor and the output member can be engaged with each other through a relative movement in an axial direction. The engagement can limit a relative rotation between the adaptor and the output member. The transmission mechanism can comprise a locking member rotatably provided on the output member. The locking member can pass through the output member along an axial direction of the output member. An operating portion provided on the locking member can be operated to connect the locking member to or disconnect the locking member from the adaptor, thereby a convenient attachment and/or detachment of the transmission mechanism is effected. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an exploded view of a transmission mechanism in accordance with embodiments of the disclosure. 
         FIG. 2  shows an exploded view of the transmission mechanism of  FIG. 1  from another point of view. 
         FIG. 3  shows a holding member and a transmission shaft of the transmission mechanism of  FIG. 1 . 
         FIG. 4  shows an exploded view of the holding member and the transmission shaft of the transmission mechanism of  FIG. 3 . 
         FIG. 5  shows a follow focus having the transmission mechanism of  FIG. 1  in accordance with a first embodiment of the disclosure. 
         FIG. 6  shows an exploded view of the follow focus of  FIG. 5 . 
         FIG. 7  shows an exploded view of the follow focus of  FIG. 5  from another point of view. 
         FIG. 8  shows the transmission mechanism and a power device of the follow focus of  FIG. 5 . 
         FIG. 9  shows an exploded view of the transmission mechanism and the power device of  FIG. 8 . 
         FIG. 10  shows an exploded view of the transmission mechanism and the power device of  FIG. 8  from another point of view. 
         FIG. 11  shows a cross-sectional view of the transmission mechanism and the power device of  FIG. 8  along an XI-XI line. 
         FIG. 12  shows a cross-sectional view of the follow focus of  FIG. 5  along an XII-XII line. 
         FIG. 13  shows a follow focus having the transmission mechanism of  FIG. 1  in accordance with a second embodiment of the disclosure. 
         FIG. 14  shows an imaging device having the follow focus of  FIG. 5  in accordance with embodiments of the disclosure. 
     
    
    
     LIST OF REFERENCE NUMERALS 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
             
            
               
                   
                 Transmission mechanism 
                 100 
               
               
                   
                 Adaptor 
                  10 
               
               
                   
                 Transmission shaft 
                  11 
               
               
                   
                 Mounting portion 
                 111 
               
               
                   
                 Engaging portion 
                 112 
               
               
                   
                 Protruding block 
                 113 
               
               
                   
                 Slot 
                 114 
               
               
                   
                 Accommodating hole 
                 115 
               
               
                   
                 Collar 
                 116 
               
               
                   
                 Transmission wheel 
                  12 
               
               
                   
                 Shaft hole 
                 121 
               
               
                   
                 Gear tooth 
                 122 
               
               
                   
                 Holding member 
                  20 
               
               
                   
                 Body 
                  21 
               
               
                   
                 First surface 
                 211 
               
               
                   
                 Second surface 
                 212 
               
               
                   
                 Via hole 
                 213 
               
               
                   
                 Guide hole 
                 214 
               
               
                   
                 Screw hole 
                 215 
               
               
                   
                 Holding portion 
                  22 
               
               
                   
                 Protrusion 
                 221 
               
               
                   
                 Output gear 
                  30 
               
               
                   
                 First end face 
                  31 
               
               
                   
                 Second end face 
                  32 
               
               
                   
                 Through hole 
                  33 
               
               
                   
                 Stepped hole 
                  34 
               
               
                   
                 Groove 
                  35 
               
               
                   
                 Receiving slot 
                 351 
               
               
                   
                 Guide strip 
                  36 
               
               
                   
                 Connector 
                  37 
               
               
                   
                 Meshing portion 
                  38 
               
               
                   
                 Rib 
                 381 
               
               
                   
                 Locking member 
                  40 
               
               
                   
                 Operating portion 
                  41 
               
               
                   
                 Step portion 
                 411 
               
               
                   
                 Fixing surface 
                 412 
               
               
                   
                 Connecting rod 
                  42 
               
               
                   
                 External thread 
                 421 
               
               
                   
                 Follow focus 
                 200, 300 
               
               
                   
                 Casing 
                  50 
               
               
                   
                 Latching member 
                  51 
               
               
                   
                 Knob 
                 511 
               
               
                   
                 Stationary portion 
                 512 
               
               
                   
                 Movable portion 
                 513 
               
               
                   
                 Receiving hole 
                 514 
               
               
                   
                 Clearing slot 
                  52 
               
               
                   
                 Housing hole 
                 521 
               
               
                   
                 Receiving cavity 
                  53 
               
               
                   
                 Power device 
                  60 
               
               
                   
                 Output shaft 
                  61 
               
               
                   
                 Screw tooth 
                 611 
               
               
                   
                 Imaging device 
                 400 
               
               
                   
                 Gimbal 
                  70 
               
               
                   
                 Carrier 
                  71 
               
               
                   
                 Carrying platform 
                  72 
               
               
                   
                 Mounting rod 
                  73 
               
               
                   
                 First operating handle 
                  74 
               
               
                   
                 Second operating handle 
                  75 
               
               
                   
                 Carrying rod 
                  76 
               
               
                   
                 Imaging element 
                  80 
               
               
                   
                 Gear ring 
                  81 
               
               
                   
                 Output member 
                  90 
               
               
                   
               
            
           
         
       
     
     Illustrative embodiments of the disclosure will be described with reference to the drawings. 
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     Illustrative embodiments of the disclosure are described with reference to the drawings. The embodiments and features can be combined with one another provided that they are technically compatible. 
     Referring to  FIGS. 1-4 , a transmission mechanism  100  in accordance with embodiments of the disclosure can comprise an adaptor  10 , an output member  90  and a locking member  40 . The adaptor  10  can be detachably connected to the output member  90 . 
     The adaptor  10  can be connected to a power device and transmit a power from the power device to the output member, such that the output member  90  can output the power. The adaptor  10  can drive a coaxial rotation of the output member  90  to allow the output member  90  to output the power. The adaptor  10  and the output member  90  can be engaged to or disengaged from each other by a relative movement along an axial direction, such that the transmission mechanism  100  can be brought into an assembled state or a disassembled state. The engagement can limit a relative rotation between the adaptor  10  and the output member  90 . The locking member  40  can be rotatably provided on the output member  90 . The locking member  40  can pass through the output member  90  along an axial direction of the output member  90 , and be detachably connected to the adaptor  10 . A relative movement between the adaptor  10  and the output member  90  along an axial direction can be limited once the locking member  40  is connected with the adaptor  10 . 
     The output member  90  can comprise a holding member  20  and an output gear  30 . The locking member  40  can be movably connected to the output gear  30  and the holding member  20 . The locking member  40  can be rotated relative to the output member  90  and be connected to or disconnected from the adaptor  10  during the rotation, such that the holding member  20  and the adaptor  10  can be engaged or disengaged, thereby the transmission mechanism  100  is attached or detached. 
     The adaptor  10  can be connected to the power device. The adaptor  10  can be engaged to or disengaged from the output member  90  by connecting to or disconnecting from the locking member  40  thereby bringing the transmission mechanism  100  into the assembled state or the disassembled state. The adaptor  10  can comprise a transmission shaft  11  and a transmission wheel  12 . The transmission shaft  11  can be coupled to the transmission wheel  12  and rotate coaxially with the transmission wheel  12 . The power device can drive a rotation of the transmission shaft  11  by the transmission wheel  12 . 
     A mounting portion  111  can be formed on the transmission shaft  11 . The mounting portion  111  can prevent a movement of the transmission wheel  12  relative to the transmission shaft  11  along a circumferential direction and an axial direction of the transmission shaft  11 . In some embodiments, the mounting portion  111  can be a plane. In some embodiments, the mounting portion  111  can comprise four mounting portions  111  which are equally arranged along the circumferential direction of the transmission shaft  111 . It will be appreciated that, the number of the mounting portions  111  is not limited to that described in the illustrative embodiments. For instance, the number of the mounting portions can be more than four or less than four. An engaging portion  112  can be formed at each end of the transmission shaft  11 . The engaging portion  112  can abut against or release from the holding member  20  to bring the transmission mechanism  100  into the assembled state or the disassembled state. In some embodiments, the engaging portion  112  can comprise a plurality of protruding blocks  113  provided on an end face of the transmission shaft  11 . In some embodiments, the plurality of protruding blocks  113  can be arranged along a circumference of the end face of the transmission shaft  11  with an interval therebetween. A slot  114  can be formed between two adjacent protruding blocks  113 . The slot  114  can be meshed with the holding member  20  to engage the adaptor  10  with the holding member  20 . 
     The transmission shaft  11  can be provided with an accommodating hole  115 . A central axis of the accommodating hole  115  can substantially coincide with a central axis of the transmission shaft  11 . A collar  116  can extend from a position at a middle of an inner wall of the accommodating hole  115  (refer to  FIG. 11 ). The collar  116  can extend along a circumferential direction of the accommodating hole  115 . The transmission shaft  11  can be connected to the locking member  40  through the collar  116 . A thread can be formed on a surface of the collar  116  facing a central axis thereof. The thread can be meshed with the locking member  40  to connect or disconnect the transmission shaft  11  with the locking member  40 . It will be appreciated that, the collar  116  can be omitted in alternative embodiments. For instance, a thread can be formed on the inner wall of the accommodating hole  115 , and the thread on the inner wall of the accommodating hole  115  can be meshed with the locking member  40 , such that the transmission shaft  11  and the locking member  40  can be connected to or disconnected from each other. 
     The transmission wheel  12  can be sleeved on the transmission shaft  11 . The transmission wheel  12  can be meshed with the power device to drive a rotation of the transmission shaft  11 . In some instances, the transmission wheel  12  can be meshed with the mounting portion  111  of the transmission shaft  11 , such that a movement of the transmission wheel  12  relative to the transmission shaft  11  along the circumferential direction and the axial direction of the transmission shaft  11  can be limited by the mounting portion  111 . The transmission wheel  12  can be provided with a shaft hole  121 , within which the transmission shaft  11  can be partially received. The mounting portion  111  and the shaft hole  121  can be meshed with each other, and the transmission wheel  12  can be provided on the mounting portion  111  through the shaft hole  121 . The transmission wheel  12  can comprise a plurality of gear teeth  122 , through which the transmission wheel  12  can be meshed with the power device. The transmission wheel  12  can be provided in a substantially disk-like shape. The plurality of gear teeth  122  can be arranged on a circumference of the transmission wheel  12  with an interval therebetween. An angle between a lengthwise direction of each one of the gear teeth  122  and an axial direction of a central axis of the transmission wheel  12  can be an acute angle. In some embodiments, the adaptor  10  can be a worm wheel shaft, and the transmission wheel  12  can be a worm wheel. 
     The holding member  20  can be detachably connected to the adaptor  10 . The holding member  20  can comprise a body  21  and a holding portion  22  provided on the body  21 . The holding portion  22  can abut against or release from the engaging portion  112  to cause the holding member  20  and the adaptor  10  to abut against or release from each other. The body  21  can comprise a first surface  211  and a second surface  212  facing away from each other. The holding portion  22  can be provided on the first surface  211 . The body  21  can be provided with a via hole  213  through which the locking member  40  passes. The via hole  213  can penetrate through the first surface  211  and the second surface  212 . 
     The body  21  can be provided with a guide hole  214  and a screw hole  215 . The guide hole  214  can be an arc-shaped hole for guiding a connection between the holding member  20  and the output gear  30 . The holding member  20  can be connected to the output gear  30  through the screw hole  215 . In some embodiments, three guide holes  214  and three screw holes  215  can be provided. The three guide holes  214  and the three screw holes  215  can be spaced apart from each other and equally arranged along a circle having a center coinciding on a central axis of the via hole  213 . It will be appreciated that, in other embodiments, the number of the guide holes  214  or the screw holes  215  can vary according to actual requirements. 
     The holding portion  22  can comprise a plurality of protrusions  221  meshed with the slots  114 . The protrusions  221  can be engaged into or disengaged from the slots  114  to cause the holding member  20  and the adaptor  10  to abut against or release from each other. A shape and a position of the plurality of protrusions  221  can correspond to a shape and a position of the plurality of slots  114 . In some embodiments, the plurality of protrusions  221  can be arranged along a circumference of the via hole  213  with an interval therebetween. 
     The output gear  30  can be connected to the holding member  20  and the locking member  40  to drive a rotation of a load, such as a lens ring of an imaging device. The output gear  30  can comprise a first end face  31  and a second end face  32  facing away from each other. The first end face  31  can be proximal to the locking member  40  while the second end face  32  can be distal to the locking member  40 . The output gear  30  can be provided with a through hole  33 , within which the locking member  40  can be partially received. The output gear  30  can be provided with a stepped hole  34 , through which the output gear  30  can be connected to the holding member  20 . In some embodiments, three stepped hole  34  can be provided. Positions of the three stepped holes  34  can correspond to positions of the three screw holes  215 . Three connectors  37  can be respectively received within the three stepped holes  34  and the three screw holes  215 , such that the output gear  30  is connected with the holding member  20 . In some embodiments, the connectors  37  can be screws. It will be appreciated that, in other embodiments, the connectors  37  can be provided as other parts such as bolts or pins. The output gear  30  and the holding member  20  can be connected to each other by other means. 
     The output gear  30  can be provided with a groove  35 . The groove  35  can penetrate through the second end face  32  and be in communication with the stepped holes  34  and the through hole  33  to receive the holding member  20 . A bottom surface of the groove  35  facing the holding member  20  can be provided with a receiving slot  351  which is in communication with the through hole  33 . A size of the receiving slot  351  in a direction perpendicular to an axial direction of the output gear  30  can be greater than a size of the through hole  33  in a direction perpendicular to the axial direction of the output gear  30 . A guide strip  36  can be fixed on the bottom surface of the groove  35  facing the holding member  20 . The guide strip  36  can be inserted into the guide hole  214  to provide a guidance in connecting the output gear  30  with the holding member  20 . A shape of the guide strip  36  can correspond to a shape of the guide hole  214 . In some embodiments, three guide strips  36  can be provided. Positions of the three guide strips  36  can correspond to positions of the three guide holes  214 . The three guide strips  36  can be equally arranged along a circumference of the receiving slot  351 . It will be appreciated that, in other embodiments, the number of the guide strips  36  can vary according to actual requirements. 
     The output gear  30  can comprise a meshing portion  38  through which the load can be driven by the output gear  30 . In some embodiments, the meshing portion  38  can comprise a plurality of ribs  381 . The output gear  30  can be provided in a substantially disk-like shape. The plurality of ribs  381  can be equally arranged along a circumference of the output gear  30 . The meshing portion  38  can be meshed with the load to drive the load. In some embodiments, the rib  381  can be a gear teeth. 
     It will be appreciated that, the holding member  20  can be integrally formed with the output gear  30 . Optionally, the holding portion  22  can be directly formed on the output gear  30  without providing a separate holding member  20 . 
     The locking member  40  can be movably connected to the output gear  30  and the holding member  20 . The locking member  40  can be connected to or disconnected from the adaptor  10  by a rotation relative to the output gear  30  and the holding member  20 . The locking member  40  can comprise an operating portion  41  and a connecting rod  42  fixedly connected to the operating portion  41 . The connecting rod  42  can be meshed with the collar  116  to connect the locking member  40  to or disconnect the locking member  40  from the adaptor  10 . The operating portion  41  can be operated to engage the locking member  40  to the adaptor  10  or disengage the locking member  40  from the adaptor  10 . 
     The operating portion  41  can be provided in a substantially stepped shape. The operating portion  41  can comprise a step portion  411  to be received within the receiving slot  351 . The step portion  411  can comprise a fixing surface  412  facing the holding portion  20 . The connecting rod  42  can be fixed on the fixing surface  412 . In some embodiments, a size of the step portion  411  in a direction perpendicular to the axial direction of the output gear  30  can be greater than the size of the through hole  33  in a direction perpendicular to the axial direction of the output gear  30 . An external thread  421  can be provided on the connecting rod  42 . The external thread  421  can be threadedly meshed with the thread of the collar  116 . The locking member  40  can be connected with the adaptor  10  by a threaded connection between the external thread  421  and the thread of the collar  116 . 
     In assembling the transmission mechanism, the operating portion  41  of the locking member  40  can be inserted into the through hole  33 , and the step portion  411  of the operating portion  41  can be received within the receiving slot  351 . The three connectors  37  can be respectively received within the three stepped holes  34  and the three screw holes  215 , and the three guide strips  36  can be respectively inserted into the three guide holes  214 , such that the output gear  30  can be fixedly connected to the holding member  20 . The holding member  20  can be received within the groove  35 . The connecting rod  42  of the locking member  40  can pass through the via hole  213  and protrude from the holding member  20 . The operating portion  41  can be partially received within the through hole  33 , with the fixing surface  412  and the holding member  20  facing each other. It will be appreciated that, in other embodiments, the guide strips  36  and the guide holes  214  can be omitted. 
     The step portion  411  of the operating portion  41  can be received within the receiving slot  351 . The step portion  411  can be positioned between the holding member  20  and a bottom surface of the receiving slot  351 . The size of the step portion  411  in a direction perpendicular to the axial direction of the output gear  30  can be greater than the size of the through hole  33  in a direction perpendicular to the axial direction of the output gear  30 , such that the locking member  40  can be prevented from releasing from the output gear  30 . The holding member  20  can be fixedly connected to the output gear  30  and cover the receiving slot  351 , such that a release of the locking member  40  from the receiving slot  351  and the groove  35  of the output gear  30  can be prevented by the holding member  20 . 
     The external thread of the connecting rob  42  can be threadedly connected to the thread of the collar  116  by rotating the operating portion  41  along a predetermined direction by a predetermined angle, such that the connecting rod  42  can be partially received in the collar  116 . The protrusions  221  of the holding member  20  can be engaged into the slots  114  of the adaptor  10 , such that the holding member  20  and the adaptor  10  can abut against each other through the engaging portion  112  and the holding portion  22  to bring the transmission mechanism  100  into the assembled state. The connecting rod  42  can be gradually disengaged from the collar  116  by rotating the operating portion  41  along a direction opposite to the predetermined direction by the predetermined angle, such that the locking member  40  can be disengaged from the adaptor  10 . The holding member  20  can be detached from the adaptor  10 , and the protrusions  211  can be detached from the slots  114  to bring the transmission mechanism  100  into the disassembled state. 
     Referring to  FIGS. 5-12 , a follow focus  200  in accordance with a first embodiment of the disclosure can comprise the transmission mechanism  100 , a casing  50  and a power device  60 . The transmission mechanism  100  can be connected to the casing  50 . The power device  60  can provide power to the transmission mechanism  100 , and the transmission mechanism  100  can drive a load. In some embodiments, the power device  60  can be provided within the casing  50 , the transmission mechanism  100  can be provided on the casing  50  through the adaptor  10 , and the adaptor  10  can be connected to the power device  60 . The power device  60  can drive a rotation of the output gear  30  through the adaptor  10 . 
     The casing  50  can be connected to a latching member  51  through which the casing  50  can be detachably connected to a carrier. The latching member  51  can comprise a knob  511 , a stationary portion  512  and a movable portion  513 . The knob  511  can be movably connected to the casing  50 , and can be capable of rotating relative to the casing  50  to bring the latching member  51  into a locked state or a rotatable state. The stationary portion  512  can be rotatably connected to one end of the movable portion  513 , and the other end of the movable portion  513  can be connected to the knob  51 . The knob  511  can drive a movement of the movable portion  513 , such that the movable portion  513  can be rotated relative to the stationary portion  512  to bring the latching member  51  into the locked state or the rotatable state. When the latching member  51  is in the locked state, a receiving hole  514  for partially receiving the carrier can be formed by the movable portion  513  and the stationary portion  512 . 
     A clearing slot  52  can be formed on the casing  50  to accommodate the output member  90  upon assembling the follow focus  200 . In some embodiments, two clearing slot  52  can be provided facing away from each other. The casing  50  can be provided with a housing hole  521  in communication with the clearing slots  52 . The adaptor  10  can be mounted within the housing hole  521 , and the engaging portion  112  can protrude from the housing hole  521 . The casing  50  can be provided with a receiving cavity  53  in communication with the housing hole  521 . The power device  60  can be received in the receiving cavity  53 . The power device  60  can comprise an output shaft  61  which is meshed with transmission wheel  12  of the adaptor  10 . The power device  60  can drive the adaptor  10  through the output shaft  61  and the transmission wheel  12 . A lengthwise direction of the output shaft  61  can be substantially perpendicular to an axial direction of a central axis of the adaptor  10 . Screw teeth  611  can be provided on a circumference of the output shaft  61 . The screw teeth  611  can be meshed with the gear teeth  122  of the transmission wheel  12  to drive a rotation of the adaptor  10 . 
     Referring to  FIG. 13 , a follow focus  300  in accordance with a second embodiment of the disclosure is shown. The follow focus  300  can be substantially similar to the follow focus  200 , except that the follow focus  300  can comprise two output members  90 . The two output members  90  can be detachably connected to the engaging portions  112  at two ends of the transmission shaft  11  of the adaptor  10  respectively through a locking member  40 . The adaptor  10  can drive a synchronous rotation of the two holding members  20 . The two clearing slots  52  can respectively accommodate the two holding members  20 , the two output gears  30  and the two locking members  40 . 
     Referring to  FIG. 14 , an imaging device  400  in accordance with embodiments of the disclosure can comprise a follow focus  200 , a gimbal  70  and an imaging element  80 . The imaging element  80  and the follow focus  200  can be provided on the gimbal  70 . The follow focus  200  can drive a focusing of the imaging element  80 . In some embodiments, the imaging element  80  can be a camera. It will be appreciated that, in other embodiments, the imaging element  80  can be other image capturing element such as a video camera. The gimbal  70  can be a carrier, and the imaging element  80  can be a load. The gimbal  70  can comprise a carrier  71 , a carrying platform  72 , a mounting rod  73 , a first operating handle  74 , a second operating handle  75  and a carrying rod  76 . The carrying platform  72  and the mounting rod  73  can be provided on the carrier  71 , and the imaging element  80  can be installed on the carrying platform  72 . The first operating handle  74  and the second operating handle  75  can be connected to the mounting rod  73  and can facilitate a photographer to grip or a mounting to other parts. The carrying rod  76  can be connected to the carrying platform  72  and can be mounted in the receiving hole  514  of the latching member  51 . The follow focus  200  can be detachably connected at an arbitrary position on the carrying rod  76  of the gimbal  70  through the latching member  51 . 
     The follow focus  200  can comprise a gear ring  81  sleeved on a lens ring of the imaging element  80 . A central axis of the gear ring  81  can be substantially perpendicular to a central axis of the output gear  30 . The power device  60  can drive the transmission mechanism  100 . The transmission mechanism  100  can drive a rotation of the gear ring  81  through the output gear  30  to rotate the lens ring of the imaging element  80 , thereby a focusing is effected. It will be appreciated that, in other embodiments, the imaging device  400  can employ another type of follow focus such as the follow focus  300  in place of the follow focus  200 . The follow focus  300  can drive the rotation of the lens ring of the imaging element  80  through the gear ring  81  to effect a focusing. 
     It will be appreciated that, the gear ring  81  can be sleeved directly on an aperture ring of the imaging element  80 . The power device  60  can drive the transmission mechanism  100 , and the transmission mechanism  100  can drive the rotation of the gear ring  81  through the output gear  30  to rotate the aperture ring of the imaging element  80 , thereby an aperture adjustment is effected. 
     A control assembly (not shown) can be provided on the gimbal  70  of the imaging device  400 . The control assembly can be provided on the carrying platform  72  which carries the imaging element  80 . The control assembly can comprise a measuring part for detecting or obtaining status information associated with the imaging element  80 . The status information can comprise a velocity, a direction, an attitude, a gravity, an acceleration, a position and/or a linear velocity and/or acceleration, a direction or an inclination angle. In some embodiments, the measuring part can comprise an inertial measurement unit (IMU). The IMU can comprise one or more of a gyroscope, a velocity sensor, an accelerometer, a magnetometer and the like. The control assembly can comprise a controller configured to calculate an attitude information associated with the imaging element  80  based upon a status information obtained by the measuring part. For example, the detected angle and/or linear acceleration of the imaging element  80  can be used to calculate an attitude information of the imaging element  80  about a pitch axis, a roll axis and a yaw axis of the gimbal  70 . The controller can output one or more motor signals based upon the calculated attitude information of the imaging element  80 . The gimbal  70  can comprise a motor assembly. The motor assembly can directly drive the gimbal  70  based upon the one or more motor signals to effect a rotation of the imaging element  80  about at least one of the pitch axis, the roll axis or the yaw axis of the gimbal  70 , such that the imaging element  80  can be stabilized, and a quality of an image of an imaged object obtained by the imaging element  80  can be improved. 
     With the transmission mechanism, the follow focus, the follow focus actuator and the imaging device of the disclosure, the adaptor and the output member can be engaged with each other through a relative movement in an axial direction. The engagement can limit a relative rotation between the adaptor and the output member. The transmission mechanism can comprise a locking member rotatably provided on the output member. The locking member can pass through the output member along an axial direction of the output member. An operating portion provided on the locking member can be operated to connect the locking member to or disconnect the locking member from the adaptor, thereby a convenient attachment and/or detachment of the transmission mechanism is effected. 
     It will be appreciated that, numerous variations and substitutions will occur to those skilled in the art without departing from the scope of the disclosure. Those variations and substitutions made in accordance with the spirit of the disclosure are within the scope of the present disclosure.