Patent Publication Number: US-10761556-B2

Title: Rotational positioning mechanism and carrier

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 107100583, filed on Jan. 5, 2018. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND 
     Field of the Disclosure 
     The disclosure is related to a rotational positioning mechanism and a carrier, and particularly to a rotational positioning mechanism and a carrier utilizing the rotational positioning mechanism. 
     Description of Related Art 
     To meet the need for rehabilitation and medical care, currently available wheelchairs or walking aid devices are used to aid people who have difficulties in walking or those undertaking rehabilitation after surgeries or illness. The commonly seen wheelchairs are mainly provided for users to sit thereon and driven to travel in an electrical or a manual manner. The commonly seen walking aid devices mainly function in allowing the users to hold a handle thereof by hands, such that the user can be supported during the travelling process to push the walking aid device to travel, thereby reducing the burden of walking. 
     Currently carriers which are integrated with functions of wheelchair and walking aid device has been proposed, and the users can switch functions depending on individual&#39;s need. Furthermore, in the process of switching functions (i.e., sitting function and walking aid function) of the carrier, the status of the carrier is changed accordingly, for example, the bracket of the carrier is rotated relative to the body of the carrier, and the bracket is locked after being rotated to a position. However, the lock between the bracket and the body is generally completed manually, which may cause the problem of lack of reliability. 
     SUMMARY 
     The disclosure provides a rotational positioning mechanism and a carrier utilizing the rotational positioning mechanism, which have good reliability. 
     In the disclosure, a rotational positioning mechanism includes a base, a rotational shaft, a rotational plate, at least two first switches and a positioning assembly. The rotational shaft is pivoted to the base. The rotational plate is connected to the rotational shaft, and configured to rotate relative to the base along with the rotational shaft. The rotational plate has at least two first positioning portions. The two first switches are respectively disposed at the two first positioning portions. The positioning assembly is disposed at the base. The positioning assembly includes a positioning component configured to form structural interference with any one of the first positioning portions or remove the structural interference. After the positioning component forms the structural interference with any one of the first positioning portions, the positioning component abuts against the corresponding first switch, and the degree of rotating freedom of the rotational plate and the rotational shaft are restricted. 
     In an embodiment of the disclosure, the base includes at least one side wall portion, and the side wall portion has an assembly hole and a slot disposed in parallel. The positioning assembly and the rotational plate are respectively disposed at two opposite sides of the side wall portion. The rotational plate has an installing end portion penetrating through the side wall portion from the assembly hole for connecting the rotational plate. The positioning component has a second positioning portion which penetrates through the side wall portion from the slot. The second positioning portion is configured to form structural interference with any one of the first positioning portions or remove the structural interference. 
     In an embodiment of the disclosure, the rotational positioning mechanism further includes a second switch disposed in the slot. When the second positioning portion is moved away from one of the first positioning portions to remove the structural interference, the second positioning portion is separated from the first switch disposed at one of the first positioning portions and triggers the second switch to activate the rotational shaft to drive the rotational plate to rotate relative to the base. When the rotational plate is rotated relative to the base such that another first positioning portion is aligned with the second positioning portion, the second positioning portion is moved close to said another first positioning portion to form structural interference, and the second positioning portion is separated from the second switch and triggers the first switch disposed at said another first positioning portion to stop the rotational shaft from driving the rotational plate to rotate relative to the base. 
     In an embodiment of the disclosure, the positioning assembly further includes a carriage and a driver, wherein the carriage is fixed to the side wall portion and the driver is fixed to the carriage. The positioning component is pivoted to the carriage, and the driver is configured to drive the positioning component to rotate relative to the carriage such that the second positioning portion is moved in the slot to form structural interference with any one of the first positioning portions or remove the structural interference. 
     In an embodiment of the disclosure, the positioning assembly further includes an elastic component, and two opposite end portions of the elastic component are respectively connected to the carriage and the positioning component. In the process that the second positioning portion is moved away from one of the first positioning portions to remove the structural interference, the positioning component is driven by the driver to rotate relative to the carriage such that the second positioning portion is moved away from one of the first positioning portions and the elastic component is elastically deformed. After the rotational plate is rotated relative to the base such that said another first positioning portion is aligned with the second positioning portion, the elastic restoring force of the elastic component drives the positioning component to rotate relative to the carriage such that the second positioning portion is moved close to said another first positioning portion and forms the structural interference. 
     In an embodiment of the disclosure, the positioning assembly further includes a driving component coupled to the driver. The driving component is configured to be driven by the driver to push the positioning component to rotate relative to the carriage and separate from the positioning component. 
     In an embodiment of the disclosure, the rotational positioning mechanism further includes a side switch disposed at the side wall portion. The rotational plate has at least one triggering portion facing the side wall portion and disposed as corresponding to the side switch. In the process that the rotational plate is rotated relative to the base such that any one of the first positioning portions is aligned with the second positioning portion, the triggering portion triggers the side switch to activate the driver to drive the driving component to rotate relative to the carriage and separate from the positioning component. 
     In an embodiment of the disclosure, the driver is an electromagnetic valve, and the positioning assembly further includes a driving component. The driving component is coupled to the electromagnetic valve, and the driving component is connected to the positioning component. The driving component is configured to be driven by the electromagnetic valve to move back and forth and drive the positioning component to rotate relative to the carriage. 
     In an embodiment of the disclosure, the driver is a motor. 
     In an embodiment of the disclosure, the positioning assembly further includes a driver, and the positioning component is coupled to the driver. The driver is configured to drive the positioning component to move back and forth relative to the side wall portion such that the second positioning portion penetrates through the side wall portion from the slot to form structural interference with any one of the first positioning portions, or such that the second positioning portion is moved back into the slot to remove the structural interference with any one of the first positioning portions. 
     In an embodiment of the disclosure, the driver is an electromagnetic valve. 
     In an embodiment of the disclosure, the driver is a motor. The positioning assembly further includes a carriage, a first guiding component and a second guiding component, and the first guiding component and the second guiding component are disposed between the carriage and the side wall portion. The motor is fixed to the carriage. The first guiding component is coupled to the motor and sleeved on the positioning component. The second guiding component is fixed to the carriage and sleeved on the positioning component. The first guiding component is configured to be driven by the motor to rotate and drive the positioning component to be guided by the second guiding component to move back and forth. 
     In the disclosure, a carrier includes a driven component and a rotational positioning mechanism, wherein the rotational positioning mechanism includes a base, a rotational shaft, a rotational plate, at least two switches and a positioning assembly. The rotational shaft is pivoted to the base. The rotational plate is connected to the rotational shaft and configured to rotate relative to the base along with the rotational shaft. The rotational plate has at least two positioning portions. The driven component is connected to the rotational plate and configured to rotate relative to the base along with the rotational plate and the rotational shaft. The two switches are respectively disposed at the two positioning portions. The positioning assembly is disposed at the base. The positioning assembly includes a positioning component configured to form structural interference with any one of the positioning portions or remove the structural interference. After the positioning component forms the structural interference with any one of the positioning portions, the positioning component abuts against the corresponding switch, and the degree of rotating freedom of the rotational plate and the rotational shaft are restricted. 
     In summary of the above, in the rotational positioning mechanism of the disclosure, the rotational plate can be rotated automatically relative to the base along with the rotational shaft. Meanwhile, after the rotational plate is rotated to a position, based on the setting of the triggering mechanism, the rotational shaft stops rotating. Also, the positioning component of the positioning assembly form the structural interference with the rotational plate such that the status of the rotational plate is locked. After the status of the rotational plate is locked, even if the rotational plate is subjected to an external force, the rotational plate is not easily rotated relative to the base. Therefore, both of the rotational positioning mechanism and the carrier utilizing the rotational positioning mechanism in the disclosure have good reliability. 
     In order to make the aforementioned features and advantages of the disclosure more comprehensible, embodiments accompanying figures are described in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  and  FIG. 1B  are respective schematic structural views illustrating a carrier at two different viewing angles according to a first embodiment of the disclosure, and the carrier is in a first status. 
         FIG. 2A  and  FIG. 2B  are respective schematic structural views illustrating the carrier at two different viewing angles according to the first embodiment of the disclosure, and the carrier is in a second status. 
         FIG. 3A  and  FIG. 3B  are respective schematic structural views illustrating the carrier at two different viewing angles according to the first embodiment of the disclosure, and the carrier is in a third status. 
         FIG. 4A  and  FIG. 4B  are respective schematic structural views illustrating the carrier at two different viewing angles according to the first embodiment of the disclosure, and the carrier is in a fourth status. 
         FIG. 5A  and  FIG. 5B  are respective schematic structural views illustrating a positioning assembly in two actuating statuses according to a second embodiment of the disclosure. 
         FIG. 6A  and  FIG. 6B  are respective schematic structural views illustrating a positioning assembly in two actuating statuses according to a third embodiment of the disclosure. 
         FIG. 7A  and  FIG. 7B  are respective schematic structural views illustrating a positioning assembly in two actuating statuses according to a fourth embodiment of the disclosure. 
         FIG. 8A  and  FIG. 8B  are respective schematic structural views illustrating a positioning assembly in two actuating statuses according to a fifth embodiment of the disclosure. 
         FIG. 9A  and  FIG. 9B  are respective schematic structural views illustrating a positioning assembly in two actuating statuses according to a sixth embodiment of the disclosure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG. 1A  and  FIG. 1B  are respective schematic structural views illustrating a carrier at two different viewing angles according to a first embodiment of the disclosure, and the carrier is in a first status. Referring to  FIG. 1A  and  FIG. 1B , in the embodiment, a carrier  10  includes a driven component  11  and a rotational positioning mechanism  100 . Based on the rotational positioning mechanism provided by the rotational positioning mechanism  100 , the driven component  11  may be rotated or locked along with the mechanism. For example, the carrier  10  may be a wheelchair, a walking aid device, an unmanned car, or a portion of an automatic configuration, which should not be construed as a limitation to the disclosure. It should be indicated that the driven component  11  is shown in  FIG. 1A  for exemplary purpose but omitted in the other drawings. 
     The rotational positioning mechanism  100  includes a base  110 , a rotational shaft  120 , a rotational plate  130 , at least two first switches  140  and a positioning assembly  150 , wherein the base  110  includes a first side wall portion  111  and a second side wall portion  112  opposite to each other. The rotational shaft  120  penetrates through the first side wall portion  111  and the second side wall portion  112 , and pivoted to the first side wall portion  111  and the second side wall portion  112 . In other words, the rotational shaft  120  may be rotated relative to the base  110 . Specifically, the first side wall portion  111  has a first assembly hole  111   a  and a slot  111   b  disposed in parallel, and the second side wall portion  112  has a second assembly hole  112   a  aligned with the first assembly hole  111   a.  An installing end  121  of the rotational shaft  120  penetrates through the first side wall portion  111  from the first assembly hole  111   a,  wherein the rotational plate  130  is fixed to the installing end  121 , and the second side wall portion  112  and the rotational plate  130  are respectively disposed at two opposite sides of the first side wall portion  111 . On the other hand, a driving end  122  of the rotational shaft  120  penetrates through the second side wall portion  112  from the second assembly hole  112   a  and coupled to the driver  160 . The driver  160  may be a motor which drives the rotational shaft  120  to rotate relative to the base  110 . Therefore, the rotational plate  130  and the driven component  11  connected to the rotational plate  130  can be rotated relative to the base  110  along with rotational shaft  120 . 
     The rotational plate  130  has at least two first positioning portions  131  disposed along the periphery thereof. In the embodiment, the number of the first switch  140  is equal to the number of the first positioning portion  131 , and the drawings show three first switches  140  and three first positioning portions  131  for exemplary purpose, but the disclosure provides no limitation to the number of the first switch  140  and the number of the first positioning portion  131 . On the other hand, the first positioning portion  131  may be a positioning recess that is inward from the outer periphery surface of the rotational plate  130  to the center of the rotational plate  130 , and each of the positioning recesses (i.e., first positioning portion  131 ) is provided with a first switch  140  therein. 
     The positioning assembly  150  is disposed at the first side wall portion  111 , wherein the positioning assembly  150  is disposed between the first side wall portion  111  and the second side wall portion  112 , and the positioning assembly  150  and the rotational plate  130  are respectively disposed at two opposite sides of the first sidewall portion  111 . The positioning assembly  150  includes a positioning component  151 , wherein the positioning component  151  is disposed as corresponding to the slot  111   b  and able to move back and forth in the slot  111   b.  A part of the positioning component  151  (i.e., second positioning portion  151   a ) may penetrate through the first side wall portion  111  from the slot  111   b,  in the first status shown in  FIG. 1A , the second positioning portion  151   a  of the positioning component  151  is embedded into one of the positioning recesses (i.e., first positioning portion  131 ) to form structural interference. At this time, the rotational plate  130  and the rotational shaft  120  are restricted by the positioning component  151  and thus unable to be rotated relative to the base  110 . In the meantime, the second positioning portion  151   a  embedded into the positioning recess (i.e., first positioning portion  131 ) abuts against the corresponding first switch  140  and the triggered first switch  140  transmits a first signal to a controller  161 , wherein the controller  161  and the driver  160  are electrically coupled to each other, and the controller  161  receiving the first signal controls the driver  160  to stop operating to avoid destroying the second positioning portion  151   a  embedded into the positioning recess (i.e., first positioning portion  131 ). 
     In the embodiment, the positioning assembly  150  further includes a carriage  152 , a driver  153 , an elastic component  154  and a driving component  155 , wherein the carriage  152  is fixed to the first side wall portion  111 , and the driver  153  is fixed to the carriage  152 . The driver  153  may be a motor, wherein the driving component  155  is coupled to the driver  153 , and the driving component  155  is configured to be driven by the driver  153  to rotate relative to the carriage  152 . On the other hand, the two opposite end portions of the elastic component  154  are respectively connected to the carriage  152  and the positioning component  151 , wherein the elastic component  154  may be a tensile spring, and the elastic component  154  shown in  FIG. 1B  is in the status of not being stretched and deformed, thereby preventing the second positioning portion  151   a  embedded into the positioning recess (i.e., first positioning portion  131 ) from being moved out of the positioning recess (i.e., first positioning portion  131 ). 
     It should be indicated that the driving component  155  in  FIG. 1B  is in contact with the positioning component  151 , wherein a distance from a contact point of the driving component  155  and the positioning component  151  to a pivoting center (i.e., pivoting point of the positioning component  151  and the carriage  152 ) of the positioning component  151  is larger than a distance from a contact point of the driving component  155  and the positioning component  151  to a pivoting center (i.e., a pivoting point of the driving component  155  and the driver  153 ) of the driving component  155 . Based on the design of moment arm, the driver  153  can drive the driving component  155  to rotate relative to the carriage  152  through a smaller output torsion, and overcome the force applied by the elastic component  154  to the positioning component  151  to push the positioning component  151  to rotate relative to the carriage  152 . 
       FIG. 2A  and  FIG. 2B  are respective schematic structural views illustrating the carrier at two different viewing angles according to the first embodiment of the disclosure, and the carrier is in a second status. Referring to  FIG. 2A  and  FIG. 2B , in the process that the driver  153  drives the driving component  155  to rotate relative to the carriage  152  along a rotating direction R, and the driving component  155  pushes the positioning component  151  to rotate relative to the carriage  152  along the rotating direction R, the second positioning portion  151   a  of the positioning component  151  is moved away from the positioning recess (i.e., first positioning portion  131 ). Specifically, after the second positioning portion  151   a  of the positioning component  151  is moved out of the positioning recess (i.e., first positioning portion  131 ), the structural interference between the second positioning portion  151   a  and the positioning recess (i.e., first positioning portion  131 ) is removed. 
     In the embodiment, the rotational positioning mechanism  100  further includes the second switch  141 , wherein the second switch  141  is disposed in the slot  111   b,  and for example, installed at an inner wall surface of the slot  111   b  away from the rotational shaft  120 . After the second positioning portion  151   a  of the positioning component  151  is moved out of the positioning recess (i.e., first positioning portion  131 ), the second positioning portion  151   a  is moved toward the inner wall surface of the slot  111   b  away from the rotational shaft  120  and abuts against the second switch  141 . The triggered second switch  141  transmits a second signal to the controller  161 , wherein the controller  161  and the driver  153  are electrically coupled together, and the controller  161  receiving the second signal controls the driver  153  to stop operating, thereby avoiding destroying the second switch  141  and the second positioning portion  151   a  that abut against each other. On the other hand, the positioning component  151  after rotation causes the elastic component  154  to be stretched and deformed, and is elastically deformed. After the driver  153  stops operating, the driving component  155  is locked in a status shown in  FIG. 2B . Since the positioning component  151  vertically abuts against the driving component  155 , and the force applied by the positioning component  151  to the driving component  155  passes through the rotational axis of the driving component  155 , the positioning component  151  and the elastic component  154  can be maintained in the status shown in  FIG. 2B . In other words, the elastic component  154  in such status cannot be elastically restored and drive the positioning component  151  to rotate relative to the base  110  along the opposite direction of the rotating direction R 1 . 
       FIG. 3A  and  FIG. 3B  are respective schematic structural views illustrating the carrier at two different viewing angles according to the first embodiment of the disclosure, and the carrier is in a third status. Referring to  FIG. 3A  and  FIG. 3B , in the condition where the controller  161  receives the second signal but not receive the first signal, the controller  161  activates the driver  160  to operate to drive the rotational shaft  120  to rotate. Meanwhile, the rotational shaft  120  drives the rotational plate  130  to rotate relative to the base  110  along the rotational direction R 1 . In the embodiment, the rotational positioning mechanism  100  further includes a side switch  142  disposed at the first side wall portion  111 , and the rotational plate  130  has at least one triggering portion  132  facing the side wall portion  111  and disposed as corresponding to the side switch  142 . In the embodiment, the side switch  142  may be a switch button, and other embodiments may adopt a variable resistance; the disclosure is not limited thereto. 
     In the process that the rotational plate  130  is rotated relative to the base  110  along the rotating direction R 1 , the trigger portion  132  is moved to pass through the side switch  142  and triggers the side switch  142  as shown in  FIG. 2B  and  FIG. 3B . The triggered side switch  142  transmits a third signal to the controller  161 , and the controller  161  receiving the third signal activates the driver  153  to operate to drive the driving component  155  to rotate relative to the carriage  152  along the rotating direction R or the opposite direction thereof to be separated from the positioning component  151 . After the support for the driving component  155  is removed, the positioning component  151  is driven by the elastic restoring force of the elastic component  154  to rotate relative to the carriage  152  along the opposite direction of the rotating direction R and abuts against the outer periphery surface of the rotational plate  130  as shown in  FIG. 3A . At this time, the second positioning portion  151   a  and the second switch  141  are separated from each other, and the second switch  141  stops transmitting the second signal to the controller  161 ; the controller  161  that does not receive the second signal controls the driver  153  to stop operating. 
       FIG. 4A  and  FIG. 4B  are respective schematic structural views illustrating the carrier at two different viewing angles according to the first embodiment of the disclosure, and the carrier is in a fourth status. Referring to  FIG. 4A  and  FIG. 4B , the rotational plate  130  is continuously rotated relative to the base  110  along the rotating direction R 1  until the second positioning portion  151   a  is aligned with the next positioning recess (i.e., first positioning portion  131 ). After the second positioning portion  151   a  is aligned with the next positioning recess (i.e., first positioning portion  131 ), the positioning component  151  is driven by the elastic restoring force of the elastic component  154  to rotate relative to the carriage  152  along the opposite direction of the rotating direction R (see  FIG. 3B ), such that the second positioning portion  151   a  is moved into the next positioning recess (i.e., first positioning portion  131 ) to form structural interference. Meanwhile, the second positioning portion  151   a  abuts against the corresponding first switch  140 , the triggered first switch  140  transmits the first signal to the controller  161 , and the controller  161  receiving the first signal controls the driver  160  to stop operating, thereby avoiding destroying the second positioning portion  151   a  embedded into the positioning recess (i.e., first positioning portion  131 ). 
     In the embodiment, the positioning component  151  is a solid structure; in other embodiments, the positioning component may be provided with an opening or other structural weakness. In this manner, when the second positioning portion of the positioning component is embedded into the positioning recess (i.e., first positioning portion) of the rotational plate, if an external force forcefully destroys the locking status of the rotational plate, the positioning component subjected to the external force can be destroyed first to avoid causing damage to the rotational plate and other components. 
     Other embodiments are incorporated below to facilitate understanding of the disclosure. It should be indicated that the reference numeral and some content used in the previous embodiments are incorporated in the following embodiments, wherein the same reference numerals denote the same or similar components, and the same technical content is omitted. The previous embodiments may serve as reference for the omitted descriptions, and thus no repetition is incorporated herein. 
       FIG. 5A  and  FIG. 5B  are respective schematic structural views illustrating a positioning assembly in two actuating statuses according to a second embodiment of the disclosure. Referring to  FIG. 5A  and  FIG. 5B , a positioning assembly  150   a  in the embodiment is adaptable for the rotational positioning mechanism  100  in the first embodiment, and the main difference between the positioning assembly  150   a  and the positioning assembly  150  in the first embodiment is that the positioning component  151  of the positioning assembly  150   a  is directly coupled to the driver  153 . Moreover, the positioning component  151  may be driven by the driver  153  to rotate relative to the carriage  152  along the rotating direction R. On the other hand, the elastic restoring force of the elastic component  154  can overcome the self-locking force of the driver  153  to drive the positioning component  151  to rotate relative to the carriage  152  along the opposite direction of the rotating direction R. 
       FIG. 6A  and  FIG. 6B  are respective schematic structural views illustrating a positioning assembly in two actuating statuses according to a third embodiment of the disclosure. Referring to  FIG. 6A  and  FIG. 6B , a positioning assembly  150   b  in the embodiment is adaptable for the rotational positioning mechanism  100  in the first embodiment, and the main difference between the positioning assembly  150   b  and the positioning assembly  150  in the first embodiment is that the positioning component  151  of the positioning assembly  150   b  is directly coupled to the driver  153 . Moreover, the positioning component  151  may be driven by the driver  153  to rotate relative to the carriage  152  along the rotating direction R or the opposite direction thereof. 
       FIG. 7A  and  FIG. 7B  are respective schematic structural views illustrating a positioning assembly in two actuating statuses according to a fourth embodiment of the disclosure. Referring to  FIG. 7A  and  FIG. 7B , a positioning assembly  150   c  in the embodiment is adaptable for the rotational positioning mechanism  100  in the first embodiment, and the main difference between the positioning assembly  150   c  and the positioning assembly  150  in the first embodiment is that the driver of the positioning assembly  150   c  is an electromagnetic valve  156 , and a driving component  155   a  is coupled to the electromagnetic valve  156 . The driving component  155   a  is connected to the positioning component  151 , configured to be driven by the electromagnetic valve  156  to move back and forth along a moving direction D, and drive the positioning component  151  to rotate relative to the carriage  152  along the rotating direction R or the opposite direction thereof. 
       FIG. 8A  and  FIG. 8B  are respective schematic structural views illustrating a positioning assembly in two actuating statuses according to a fifth embodiment of the disclosure. For ease of description, the first side wall portion  111  of the base  110 , the rotational plate  130  and the first switch  140  disposed at the first positioning portion  131  are illustrated for exemplary purpose. Referring to  FIG. 8A  and  FIG. 8B , a positioning assembly  150   d  in the embodiment is adaptable for the rotational positioning mechanism  100  in the first embodiment, and the main difference between the positioning assembly  150   d  and the positioning assembly  150  in the first embodiment is that the driver of the positioning assembly  150   d  is an electromagnetic valve  156   a,  wherein the electromagnetic valve  156   a  is fixed to the first side wall portion  111  and disposed as corresponding to the slot  111   b.  The positioning component  151   b  is coupled to the electromagnetic valve  156   a,  wherein the positioning component  151   b  is disposed as corresponding to the slot  111   b,  and the electromagnetic valve  156   a  is configured to drive the positioning component  151   b  to move back and forth relative to the first side wall portion  111  along a moving direction D 1 , such that the second positioning portion  151   c  of the positioning component  151   b  penetrates through the first side wall portion  111  from the slot  111   b  to form structural interference with the first positioning portion  131  (i.e., positioning recess) of the rotational plate  130 , or such that the second positioning portion  151   c  of the positioning component  151   b  is moved back into the slot  111   b  to remove the structural interference. 
     After the second positioning portion  151   c  of the positioning component  151   b  and the first positioning portion  131  (i.e., positioning recess) of the rotational plate  130  form the structural interference, the second positioning portion  151   c  of the positioning component  151   b  abuts against and triggers the first switch  140 . On the contrary, after the second positioning portion  151   c  of the positioning component  151   b  is moved back into the slot  111   b  to remove the structural interference with the first positioning portion  131  (i.e., positioning recess) of the rotational plate  130 , the second positioning portion  151   c  of the positioning component  151   b  and the first switch  140  are separated from each other. 
       FIG. 9A  and  FIG. 9B  are respective schematic structural views illustrating a positioning assembly in two actuating statuses according to a sixth embodiment of the disclosure. For ease of description, the first side wall portion  111  of a carriage  152   a,  the rotational plate  130  and the first switch  140  disposed at the first positioning portion  131  are illustrated for exemplary purpose. Referring to  FIG. 9A  and  FIG. 9B , a positioning assembly  150   e  in the embodiment is adaptable for the rotational positioning mechanism  100  in the first embodiment, and the main difference between the positioning assembly  150   e  and the positioning assembly  150  in the first embodiment is that the driver of the positioning assembly  150   e  is a motor  153   a,  and the positioning assembly  150   e  further includes a first guiding component  158  and a second guiding component  159 . The motor  153   a  is fixed to the carriage  152   a,  and the first guiding component  158  and the second guiding component  159  are disposed between the carriage  152   a  and the first side wall portion  111 . 
     The first guiding component  158  may be a screw rod, wherein an output shaft of the motor  153   a  penetrates through the carriage  152   a  and is coupled to the first guiding component  158 , and the first guiding component  158  is penetrates through a positioning component  151   d.  The second guiding component  159  may be a sliding rod disposed in pairs, wherein the second guiding component  159  is fixed to the carriage  152   a  and the first side wall portion  111  and penetrates through the positioning component  151   d.  The positioning component  151   d  is disposed as corresponding to the slot  111   b,  and a through hole (i.e., a through hole penetrated through by the first guiding component  158 ) of the positioning component  151   d  has a female thread in coordination with a male thread on the screw rod. Therefore, after the first guiding component  158  is driven by the motor  153   a,  the first guiding component  158  is rotated and drives the positioning component  151   d  to be guided by the second guiding component  159  to move back and forth relative to the first side wall portion  111  along the moving direction D 1 , such that a second positioning portion  151   e  of the positioning component  151   d  penetrates through the first side wall portion  111  from the slot  111   b  to form structural interference with the first positioning portion  131  (i.e., positioning recess) of the rotational plate  130 , or such that the second positioning portion  151   e  of the positioning component  151   d  is moved back into the slot  111   b  to remove the structural interference. 
     After the second positioning portion  151   e  of the positioning component  151   d  form the structural interference with the first positioning portion  131  (i.e., positioning recess) of the rotational plate  130 , the second positioning portion  151   e  of the positioning component  151   d  abuts against and triggers the first switch  140 . On the contrary, after the second positioning portion  151   e  of the positioning component  151   d  is moved back into the slot  111   b  to remove the structural interference with the first positioning portion  131  (i.e., positioning recess) of the rotational plate  130 , the second positioning portion  151   e  of the positioning component  151   d  and the first switch  140  are separated from each other. 
     In summary, the rotational plate in the rotational positioning mechanism of the disclosure can be automatically rotated relative to the base along with the rotational shaft. More specifically, before the rotational plate is rotated relative to the base along with the rotational shaft, it is required to remove the structural interference between the positioning component and one of the positioning portions of the rotational plate. In the meantime, by using the positioning component to activate the first triggering mechanism, the rotational plate is rotated relative to the base along with the rotational shaft. In this manner, it can be avoided that the rotational plate is forcefully rotated, which causes damage to the positioning component and the rotational plate that are structurally interfered with each other. After the next positioning portion of the rotational plate is rotated to a position and aligned with the positioning component, the positioning component and the next positioning portion of the rotational plate form structural interference automatically. Also, the first triggering mechanism is removed and the second triggering mechanism is activated via the positioning component to stop rotating the rotational shaft and the rotational plate. In this manner, it can be avoided that the positioning component and the rotational plate that are structurally interfered with each other are destroyed. After the status of the rotational plate is locked, even if the rotational plate is subjected to an external force, the rotational plate is not easily rotated relative to the base. Therefore, both of the rotational positioning mechanism and the carrier utilizing the rotational positioning mechanism in the disclosure can have good reliability. 
     Although the disclosure has been disclosed by the above embodiments, the embodiments are not intended to limit the disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosure without departing from the scope or spirit of the disclosure. Therefore, the protecting range of the disclosure falls in the appended claims.