Patent Publication Number: US-2023150404-A1

Title: Convertible seat for vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims under 35 U.S.C. § 119(a) the benefit of priority to Korean Patent Application No. 10-2021-0157269 filed on Nov. 16, 2021, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     (a) Technical Field 
     The present disclosure relates to a convertible seat for a vehicle, and more particularly, to a convertible seat for a vehicle, which includes a seatback and a seat cushion each having a plurality of individual blocks capable of ascending and descending so as to change a seat position into various forms. 
     (b) Background Art 
     Generally, a seat of a vehicle is manufactured in a structure which basically includes a seat cushion for seating, a seatback for leaning back, and a headrest for supporting the neck and head. In addition to the above structure, in order to implement a free change in seat position according to a body type and a situation of a passenger, various mechanisms for adjusting a seat position are being applied to the seat. 
     For example, the various mechanisms for adjusting a seat position may include a mechanism for adjusting a seat height, a mechanism for implementing a relaxation comfort posture, and a seatback reclining mechanism. 
     In particular, a purpose built vehicle (PBV), which is a type of autonomous vehicle, is manufactured for various purposes such as an auto camping space, a residence and rest space, a mobile warehouse, a logistics delivery space, a mobile hospital, and a food truck. Therefore, it is preferable that the PBV is equipped with seats suitable for the above purposes. 
     Accordingly, there is a demand for a seat mechanism capable of adjusting various seat positions desired by the passenger and adjusting a seat position according to a body type and a situation of the passenger. 
     The information disclosed in the Background section above is to aid in the understanding of the background of the present disclosure, and should not be taken as acknowledgement that this information forms any part of prior art. 
     SUMMARY OF THE DISCLOSURE 
     The present disclosure has been made in an effort to solve the above-described problems associated with prior art. 
     In one aspect, the present disclosure provides a convertible seat for a vehicle, which includes a seatback and a seat cushion each having a plurality of individual blocks capable of ascending and descending so as to change a seat position into various forms according to a body type and a situation of a passenger. 
     Objectives of the present disclosure are not limited to the above-described features, and other objectives of the present disclosure, which are not mentioned, can be understood by the following description and also will be apparently understood through embodiments of the present disclosure. Further, various aspects of the present disclosure can be realized by features described in the appended claims and a combination thereof. 
     In an exemplary embodiment, the present disclosure provides a convertible seat for a vehicle, which includes a base frame having a predetermined dimension of storage space, a plurality of individual blocks disposed to be ascendable and descendable in the storage space of the base frame, and a raising and lowering drive device installed in each of the individual blocks and configured to raise and lower a corresponding one of the individual blocks. 
     Each of the individual blocks may include a fixed block fixed to the base frame, and an ascending and descending block disposed to be ascendable and descendable and configured to surround the fixed block. 
     The raising and lowering drive device may be employed as a linear actuator including a cylinder mounted on a bottom of the fixed block of the corresponding one of the individual blocks, and a piston rod connected to the ascending and descending block of the corresponding one of the individual blocks. 
     Alternatively, the raising and lowering drive device may be employed as a scissor lift device including a base mounted on a bottom of the fixed block of the corresponding one of the individual blocks, a scissor frame having a lower end portion connected to the base and an upper end portion connected to the ascending and descending block of the corresponding one of the individual blocks, and an electric cylinder mounted on the scissor frame and configured to raise and lower the scissor frame. 
     In addition, the convertible seat may include a controller, a pressure sensor configured to detect a body pressure of a passenger and to transmit a detection signal to the controller and mounted on each individual block, and a proximity sensor configured to detect whether the passenger is seated and to transmit a detection signal to the controller and mounted on an individual block serving as a seatback among the individual blocks. 
     The controller may be configured to receive signals from pressure sensors, which actually sense the body pressure of the passenger, among the pressure sensors installed in the individual blocks, calculate an average pressure out of magnitudes of the pressure sensors, which actually sense the body pressure of the passenger, calculate a magnitude of an individual pressure of each of the pressure sensors which actually sense the body pressure of the passenger, and then control driving of the raising and lowering drive device in the corresponding one of the individual blocks, on which the individual pressure acts, in an ascending or descending direction according to a result of comparing the magnitude of the individual pressure with the average pressure. 
     In addition, the controller may be configured to control driving of the raising and lowering drive device in the corresponding one of the individual blocks, on which the individual pressure acts, in an ascending direction when the magnitude of the individual pressure is smaller than the average pressure, to control the driving of the raising and lowering drive device in the corresponding one of the individual blocks, on which the individual pressure acts, in a descending direction when the magnitude of the individual pressure is greater than the average pressure, and to stop the driving of the raising and lowering drive device in the corresponding one of the individual blocks, on which the individual pressure acts, when the magnitude of the individual pressure is equal to the average pressure. 
     In addition, when the controller receives a pressure detection signal of the pressure sensor actually sensing the body pressure of the passenger among the pressure sensors installed in the individual blocks and then receives a detection signal of the proximity sensor, the controller may be configured to control driving of the raising and lowering drive devices in the individual blocks disposed at the periphery of the individual blocks on which the body pressure of the passenger actually acts, in the ascending direction. 
     Meanwhile, a seat cushion extension device may be mounted at a front end portion and a bottom of the base frame, and the seat cushion extension device may include an extension pad mounted in the front end portion of the base frame using a hinge, and a single actuator including a cylinder mounted on a lower panel of the base frame and a piston rod connected to a bottom portion of the extension pad using a hinge. 
     Alternatively, a seat cushion extension device may be mounted at a front end portion and a bottom position of the base frame, and the seat cushion extension device may include a first actuator mounted on a lower panel of the base frame, an extension pad support block connected to a piston rod of the first actuator and configured to move forward or backward, a second actuator mounted on the extension pad support block, and an extension pad connected to a piston rod of the second actuator, disposed on the extension pad support block, and configured to ascend and descend together with the piston rod of the second actuator when the piston rod of the second actuator ascends and descends. 
     Other aspects and preferred embodiments of the present disclosure are discussed infra. 
     It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g. fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles. 
     The above and other features of the present disclosure are discussed infra. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features of the present disclosure will now be described in detail with reference to certain exemplary embodiments thereof illustrated in the accompanying drawings which are given hereinbelow by way of illustration only, and thus are not limitative of the present disclosure, and wherein: 
         FIG.  1    is a perspective view illustrating a state in which each individual block of a convertible seat for a vehicle switched to a default seating mode according to one exemplary embodiment of the present disclosure; 
         FIG.  2    is a side cross-sectional view taken along line A-A of  FIG.  1   ; 
         FIG.  3    is a flowchart illustrating an example in which the raising and lowering of each individual block of the convertible seat for a vehicle is controlled to be raised and lowered and controlled according to a body type of a passenger according to one exemplary embodiment of the present disclosure; 
         FIG.  4    is a perspective view illustrating a state in which each individual block of the convertible seat for a vehicle is switched to a child seat mode according to one exemplary embodiment of the present disclosure; 
         FIGS.  5 A,  5 B,  5 C and  5 D  are schematic diagrams illustrating an example in which the convertible seat for a vehicle is switched to the child seat mode according to various exemplary embodiments of the present disclosure; 
         FIG.  6    is a flowchart illustrating a control example when the convertible seat for a vehicle is switched to the child seat mode according to one exemplary embodiment of the present disclosure; 
         FIG.  7    is a side cross-sectional view illustrating a state in which each individual block of the convertible seat for a vehicle is switched to a full-bed mode according to one exemplary embodiment of the present disclosure; 
         FIG.  8    is a side cross-sectional view illustrating an example in which a seat cushion extension device is mounted on the convertible seat for a vehicle according to one exemplary embodiment of the present disclosure; and 
         FIG.  9    is a side cross-sectional view illustrating another example in which the seat cushion extension device is mounted on the convertible seat for a vehicle according to one exemplary embodiment of the present disclosure. 
     
    
    
     It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the present disclosure. The specific design features of the present disclosure as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
     In the figures, reference numbers refer to the same or equivalent parts of the present disclosure throughout the several figures of the drawing. 
     DETAILED DESCRIPTION 
     Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a perspective view illustrating a state in which each individual block of a convertible seat for a vehicle is switched to a default seating mode according to the present disclosure,  FIG.  2    is a side cross-sectional view taken along line A-A of  FIG.  1   , and a reference numeral  20  denotes a base frame. 
     The base frame  20  is manufactured in a structure which has an open upper portion and a predetermined size of storage space  22 . The base frame  20  may be mounted on an indoor floor panel of a vehicle. 
     In particular, in the storage space  22  of the base frame  20 , a plurality of individual blocks  10  serving as a seatback and a seat cushion are disposed to be ascendable and descendable. A raising and lowering drive device  30  for raising and lowering each individual block  10  is installed in each individual block  10 . 
     In this case, as shown in  FIG.  2   , the individual block  10  includes an upper open-type fixed block  12  fixedly mounted in the storage space  22  of the base frame  20 , and a lower open-type ascending and descending block  14  which surrounds the fixed block  12  and is disposed to be ascendable and descendable. 
     Actually, the ascending and descending block  14  of the individual blocks  10  is raised and lowered due to driving of the raising and lowering drive device  30 . 
     That is, the ascending and descending block  14  ascends due to upward driving of the raising and lowering drive device  30  in a state in which the fixed block  12  is fixed, and the ascending and descending block  14  descends due to downward driving of the raising and lowering drive device  30 . 
     As shown in  FIG.  2   , the raising and lowering drive device  30  may be employed as a linear actuator  33  including a cylinder  31  mounted on a bottom of the fixed block  12  of the individual block  10  and a piston rod  32  connected to a bottom of the ascending and descending block  14  of the individual block  10 . 
     In this case, the linear actuator  33  is a type of electric cylinder and, when electric power is supplied thereto, the piston rod  32  performs forward and backward motion by a gear train in the cylinder  31 . 
     Thus, when the piston rod  32  of the linear actuator  33  ascends, the piston rod  32  pushes upward the ascending and descending block  14  of the individual block  10 , and thus an ascending operation of the individual block  10 , that is, an ascending operation of the ascending and descending block  14 , may be performed. 
     On the other hand, when the piston rod  32  of the linear actuator  33  descends, the piston rod  32  pulls the ascending and descending block  14  of the individual block  10 , and thus a descending operation of the individual block  10 , that is, a descending operation of the ascending and descending block  14 , may be performed. 
     Alternatively, as shown in  FIG.  2   , the raising and lowering drive device  30  may be employed as a scissor lift device  37  including a base  34  mounted on the bottom of the fixed block  12  of the individual block  10 , a scissor frame  35  having a lower end portion connected to the base  34  and an upper end portion connected to the bottom of the ascending and descending block  14  of the individual block  10 , and an electric cylinder  36  mounted at a predetermined position of the scissor frame  35  and configured to raise and lower the scissor frame  35 . 
     Accordingly, when the electric power is supplied to the electric cylinder  36  of the scissor lift device  37 , the scissor frame  35  is deployed in an ascending direction due to a forward movement of a piston rod of the electric cylinder  36 . Simultaneously, the scissor frame  35  pushes upward the ascending and descending block  14  of the individual block  10  so that the ascending operation of individual block  10 , that is, the ascending operation of the ascending and descending block  14 , may be performed. 
     On the other hand, due to a backward movement of the piston rod of the electric cylinder  36 , the scissor frame  35  is folded and contracted in a descending direction and, simultaneously, the scissor frame  35  pulls the ascending and descending block  14  of the individual block  10  so that the descending operation of the individual block  10 , that is, the descending operation of the ascending and descending block  14 , may be performed. 
     Preferably, individual blocks  10  in the rearmost row among the plurality of individual blocks  10  need to each have a longer vertical ascending and descending distance so as to serve as a seatback. 
     To this end, it is preferable that the scissor lift device  37 , which has a longer vertical motion distance than that of the linear actuator  33 , is employed as a raising and lowering drive device mounted in the individual blocks  10  in the rearmost row among the plurality of individual blocks  10 , and the linear actuator  33  is employed as a raising and lowering drive device mounted in individual blocks  10  in the remaining rows among the plurality of individual blocks  10 . 
     Further, a pressure sensor  41  for detecting a body pressure of the passenger and transmitting the detection signal to a controller  40  is mounted in each individual block  10 , and a proximity sensor  42  for detecting whether the passenger is seated and transmitting the detection signal to the controller  40  is installed in individual blocks  10  serving as a seatback among the individual blocks  10 . 
     In particular, the controller  40  is configured to receive signals from the pressure sensors  41 , which actually sense the body pressure of the passenger, among the pressure sensors  41  installed in the individual blocks  10 , calculate an average pressure out of magnitudes of the pressure sensors  41 , which actually sense the body pressure of the passenger, calculate a magnitude of an individual pressure of each pressure sensor  41  which actually senses the body pressure of the passenger, and then control driving of the raising and lowering drive device  30  in the individual block  10 , on which the individual pressure acts, according to a result of comparing the magnitude of the individual pressure with the average pressure, in an ascending or descending direction. 
     For example, when the individual pressure of each pressure sensor  41  actually sensing the body pressure of the passenger is smaller than the average pressure of the pressure sensors  41  actually sensing the body pressure of the passenger, the controller  40  controls the driving of the raising and lowering drive device  30  in the individual block  10 , on which the individual pressure acts, in the ascending direction. When the individual pressure is greater than the average pressure, the controller  40  controls the driving of the raising and lowering drive device  30  in the individual block  10 , on which the individual pressure acts, in the descending direction. 
     In this case, when the individual pressure is equal to the average pressure, the controller  40  stops the driving of the raising and lowering drive device  30  in the individual block  10  on which the individual pressure acts. 
     In this way, according to the magnitude of the individual pressure when compared to the average pressure in response to the detection signal of the pressure sensor  41 , a height of the individual block  10  on which the actual body pressure acts is controlled to ascend or descend so that it is possible to provide a seat cushion suitable for the body type of the passenger. 
     In addition, when the controller  40  receives the individual pressure of the pressure sensors  41  actually sensing the body pressure of the passenger among the pressure sensors  41  mounted in the individual blocks  10  and then receives the detection signal of the proximity sensor  42 , the controller  40  determines that the passenger has actually ridden in a vehicle and controls driving of the raising and lowering drive device  30  in each individual block  10 , which is disposed around the individual block  10  on which the individual pressure acts, in the ascending direction. Accordingly, in addition to the individual block  10  on which the individual pressure acts, the individual blocks  10  disposed around the individual block  10  ascend to serve as an armrest and also perform a function of limiting a boarding space for infants or companion animals. 
     Meanwhile, for switching to a desired seat deformation mode among the default seating mode, a child seat mode, and a full-bed mode, the controller  40  is configured to selectively raise and lower the individual blocks  10  according to desired heights and store positions of the height-adjusted individual blocks  10  in a memory. 
     Here, an operation example of the convertible seat of the present disclosure, which has the above-described configuration, will be described as follows. 
     Default Seating Mode  FIGS.  1  and  2    illustrate a state in which each individual block of the convertible seat for a vehicle is switched to a default seating mode according to the present disclosure, and  FIG.  3    is a flowchart illustrating an example in which the raising and lowering of each individual block of the convertible seat for a vehicle is controlled to be raised and lowered and controlled to fit a body type of a passenger according to the present disclosure. 
     The default seating mode refers to a mode in which a general adult can be seated. 
     To this end, first, individual blocks  10  in the rearmost row, which serves as a seatback among the plurality of individual blocks  10 , are maximally raised (S 101 ). 
     In this case, as described above, the scissor lift device  37  is employed as the raising and lowering drive device  30  installed in the individual block  10  in the rearmost row so that the individual block  10 , that is, the ascending and descending block  14 , may be easily raised to a height enough to serve as a seatback function. 
     Next, the pressure sensor  41 , which actually senses the body pressure of the passenger, among the pressure sensors  41  respectively mounted in the plurality of individual blocks  10  detects the body pressure of the passenger, and transmits the detection signal for detected pressure to the controller  40  (S 102 ). 
     Subsequently, the controller  40  receives signals from the pressure sensors  41  actually sensing the body pressure of the passenger among the pressure sensors  41 , which are installed in the individual blocks  10  and serves as the seat cushion, calculates an average pressure out of magnitudes of the pressure sensors  41 , which actually sense the body pressure of the passenger, and calculates a magnitude of an individual pressure of each pressure sensor  41  actually sensing the body pressure the passenger (S 103 ). 
     Next, the controller  40  compares a magnitude of the average pressure with the magnitude of the individual pressure (S 104 ). 
     When the comparison result indicates that the individual pressure of each pressure sensor  41  actually sensing the body pressure of the passenger is smaller than the average pressure of the pressure sensors  41  actually sensing the body pressure of the passenger, the controller  40  controls driving of the raising and lowering drive device  30  in the individual block  10 , on which the individual pressure acts, in the ascending direction (S 105 ). 
     On the other hand, when the comparison result indicates that the individual pressure of each pressure sensor  41  actually sensing the body pressure of the passenger is greater than the average pressure of the pressure sensors  41  actually sensing the body pressure of the passenger, the controller  40  controls driving of the raising and lowering drive device  30  in the individual block  10 , on which the individual pressure acts, in the descending direction (S 106 ). 
     In this case, the piston rod  32  of the linear actuator  33  employed as the raising and lowering drive device  30  ascends to push upward the ascending and descending block  14  of the individual block  10  so that an ascending operation of the individual block  10 , that is, an ascending operation of the ascending and descending block  14  may be performed. The piston rod  32  of the linear actuator  33  descends to pull the ascending and descending block  14  of the individual block  10  so that a descending operation of the individual block  10 , that is, a descending operation of the ascending and descending block  14 , may be performed. 
     In this case, when the comparison result indicates that the individual pressure is equal to the average pressure, the controller  40  stops the driving of the raising and lowering drive device  30  in the individual block  10  on which the individual pressure acts (S 107 ). 
     As described above, according to the magnitude of the individual pressure of each pressure sensor  41  actually sensing the body pressure of the passenger when compared with the average pressure calculated by receiving signals from the pressure sensors  41  actually sensing the body pressure passenger, the height of the individual block  10  on which the body pressure actually acts is adjusted, which makes it possible to distribute a load of the passenger and, simultaneously, provide a seat cushion suitable for the body type of the passenger. 
     Child Seat Mode 
       FIG.  4    illustrates a state in which each individual block of the convertible seat for a vehicle is switched to a child seat mode according to the present disclosure,  FIGS.  5 A to  5 D  illustrate an example in which the convertible seat for a vehicle is switched to the child seat mode according to the present disclosure, and  FIG.  6    is a flowchart illustrating a control example when the convertible seat for a vehicle is switched to the child seat mode according to the present disclosure. 
     The child seat mode refers to a mode which provides a seating space suitable for a body type of a baby, and when a companion animal is seated, the child seat mode refers to a mode which provides a seating space suitable for a size of the companion animal. 
     To this end, first, the individual blocks  10  in the rearmost row, which serves as a seatback among the plurality of individual blocks  10 , are maximally raised (S 201 ). 
     In this case, as described above, the scissor lift device  37  is employed as the raising and lowering drive device  30  installed in the individual block  10  in the rearmost row so that the individual block  10 , that is, the ascending and descending block  14 , may be easily raised to a height enough to serve as a seatback function. 
     Next, the pressure sensor  41 , which actually senses the body pressure of the baby or the companion animal, among the pressure sensors  41  respectively mounted in the plurality of individual blocks  10  detects the pressure of the baby or companion animal, and transmits the detection signal for the detected pressure to the controller  40  (S 202 ). 
     For example, as shown in  FIG.  5 A , among the plurality of individual blocks  10 , an individual block  10  whose pressure is sensed by the body pressure of the baby or the companion animal may be determined. 
     Subsequently, after the controller  40  receives signals from the pressure sensors  41  having actually sensed the body pressure of the baby or the companion animal among the pressure sensors  41  installed in the individual blocks  10  serving as a seat cushion, the controller  40  controls the individual block  10 , on which the body pressure of the baby or the companion animal actually acts, that is, driving of the raising and lowering drive device  30  in the individual block  10  sensing the body pressure in the ascending direction. 
     Thus, as shown in  FIG.  5 B , due to the driving of the raising and lowering drive device  30 , the individual block  10  on which the body pressure actually acts, that is, the individual block  10  sensing the body pressure, ascends to a height suitable for the body type of the baby or the companion animal (S 203 ). 
     More specifically, the piston rod  32  of the linear actuator  33  in the individual block  10 , on which the body pressure of the baby or the companion animal actually acts, ascends to push upward the ascending and descending block  14  of the individual block  10  so that, as shown in  FIG.  5 B , the individual block  10 , that is, the ascending and descending block  14 , may ascend to a height suitable for the body type of the baby or the companion animal. 
     Next, the controller  40  checks whether a detection signal of the proximity sensor  42  is present (S 204 ). 
     In this case, since the proximity sensor  42  is mounted in the individual block  10  in the rearmost row for the seatback, detects whether the passenger is seated, and transmits the detection signal to the controller  40 , the controller  40  may check whether the detection signal of the proximity sensor  42  is present. 
     Subsequently, when the controller  40  receives a pressure detection signal of the pressure sensor  40  actually sensing the body pressure of the passenger (the baby or the companion animal) among the pressure sensors  41 , and then receives the detection signal of the proximity sensor  42 , the controller  40  controls driving of the raising and lowering drive devices  30  in individual blocks  10 ′, disposed at a periphery (both sides and a rear side) of the individual block  10 , in the ascending direction, in addition to the individual block  10  on which the body pressure of the passenger actually acts. 
     Thus, as shown in  FIGS.  5 C and  5 D , in addition to the individual block  10  on which the body pressure actually acts, the individual blocks  10 ′ disposed at the periphery of individual block  10  ascend to a height for limiting the seating space of the baby or the companion animal due to the driving of the raising and lowering drive device  30  ( 205 ). 
     More specifically, in addition to the individual block  10  on which the body pressure of the baby or the companion animal actually acts, the piston rod  32  of the linear actuator  33  in each of the individual blocks  10 ′ disposed at the periphery (both sides and the rear side) of the individual block  10  ascends to push upward the ascending and descending block  14  of the individual block  10  so that, as shown in  FIGS.  5 C and  5 D , in addition to the individual block  10  on which the body pressure of the passenger actually acts, the individual blocks  10 ′ disposed the periphery (both sides and the rear side) of the individual block  10  may ascend to provide a seating space suitable for the body type of the baby or the companion animal. 
     Full-Bed Mode 
       FIG.  7    is a side cross-section view illustrating a state in which each individual block of the convertible seat for a vehicle is switched to a full-bed mode according to the present disclosure. 
     The full-bed mode refers to a mode in which upper surfaces of the individual blocks  10  are adjusted to be coplanar with a floor of a luggage room of the vehicle to provide a sleeping and resting space to a user. 
     To this end, as shown in  FIG.  7   , the individual blocks  10  in the rearmost row serving as a seatback among the plurality of individual blocks  10  are lowered to a height of the floor of a luggage room  50 . 
     In this case, when electric power is supplied to the electric cylinder  36  of the scissor lift device  37  installed in the individual block  10  in the rearmost row, due to a backward movement of the piston rod of the electric cylinder  36 , the scissor frame  35  is folded and contracted in a descending direction and, simultaneously, the scissor frame  35  pulls the ascending and descending block  14  of the individual block  10  so that the descending operation of the individual block  10 , that is, the descending operation of the ascending and descending block  14 , may be performed. 
     In addition, as shown in  FIG.  7   , the individual blocks  10  serving as the seat cushion among the plurality of individual blocks  10  also ascend or descend to a height which is coplanar with the floor of the luggage room  50 . 
     In this case, the piston rod  32  of the linear actuator  33  installed in the individual block  10  serving as the seat cushion ascends or descends so that the ascending operation of the individual block  10 , that is, the ascending operation of the ascending and descending block  14 , may be performed. 
     In this way, the present disclosure may provide the full-bed mode for adjusting the plurality of individual blocks  10  to the same height as the luggage room  50 , thereby allowing the user to conveniently use the plurality of individual blocks  10  as a sleeping and resting space during auto camping. 
     Meanwhile, a seat cushion extension device  60  may be further mounted at a front end portion and a bottom position of the base frame  20 . 
       FIG.  8    is a side cross-sectional view illustrating an example in which a seat cushion extension device is mounted on the convertible seat for a vehicle according to the present disclosure. 
     As shown in  FIG.  8   , the seat cushion extension device  60  may include an extension pad  61  mounted on the front end portion of the base frame  20  using a hinge, and a single actuator  62  including a cylinder  62 - 1  mounted on a lower panel of the base frame  20  and a piston rod  62 - 2  connected to a bottom portion of the extension pad  61  using a hinge. 
     Thus, when electric power is applied to the single actuator  62 , the piston rod  62 - 2  mounted on the cylinder  62 - 1  moves forward and pushes and deploys the extension pad  61  so that the extension pad  61  becomes coplanar with the individual blocks  10 . 
       FIG.  9    is a side cross-sectional view illustrating another example in which the seat cushion extension device is mounted on the convertible seat for a vehicle according to the present disclosure. 
     As shown in  FIG.  9   , the seat cushion extension device  60  may include a first actuator  63  mounted on the lower panel of the base frame  20 , an extension pad support block  64  connected to a piston rod of the first actuator  63  and configured to move forward or backward, a second actuator  65  mounted on the extension pad support block  64 , and an extension pad  61  connected to a piston rod of the second actuator  65  and disposed to raise and lower the extension pad support block  64 . 
     Thus, when electric power is applied to the first actuator  63 , the piston rod of the first actuator  63  moves forward to push the extension pad support block  64 . Subsequently, when the electric power is applied to the second actuator  65 , the piston rod of the second actuator  65  ascends to push upward the extension pad  61  so that the extension pad  61  ascends to a position which is coplanar with the individual blocks  10 . 
     In this way, in the full-bed mode, the extension pad  61  may be deployed to the same heights as the individual blocks  10 , which makes it possible to allow the user to use the extension pad  61  as a more spacious sleeping and resting space. 
     The present disclosure provides the following effects through the above-described means for solving problems. 
     First, by configuring a plurality of individual blocks, serving as a seatback and a seat cushion, to be ascendable and descendable, it is possible to change a seat position in various ways according to a body type and a situation of a passenger. 
     Second, by adjusting a height of each individual block, it is possible to provide convenience of providing various sizes of seating spaces, such as a baby seating space and a seating space for a companion animal. 
     Third, it is possible to implement a full-bed mode in which each individual block is adjusted to the same height as a luggage room, thereby providing a sleeping and resting space to a user. 
     Fourth, a deployable extension pad of the seat cushion extension device is installed in a front end portion of a base frame so that the extension pad can be deployed in a full-bed mode to allow the user to use a more spacious sleeping and resting space. 
     Although the various embodiments of the present disclosure have been described in detail, the scope of the prevent disclosure is not limited to these embodiments, and various modifications and improvements made by those skilled in the art using the fundamental concept of the present disclosure, which is defined by the appended claims, may also fall within the scope of the present disclosure.