Abstract:
A medical rehabilitation bed is disclosed, relating to the technical field of self-help rehabilitation bed structures in medical instrument products. The medical rehabilitation bed comprises a bed head, a bed tail and a bed board. A pull rod is arranged at the bottom of the bed board; one end of the pull rod is mechanically connected to a bed head gearbox arranged at the bed head, and the other end of the pull rod is mechanically connected to a bed tail gear device arranged at the bed tail. Transmission systems having the same structure and capable of controlling the bed head and the bed tail to ascend and descend are arranged in the bed head and the bed tail, respectively. The transmission systems are mechanically connected to the bed head gearbox and the bed tail gear device, respectively. The medical rehabilitation bed has a compact structure and comprehensive functions.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the national phase entry of International Application No. PCT/CN2015/080651, filed on Jun. 3, 2015, which is based upon and claims priority to Chinese Patent Application No. 201410332253.9, filed on Jul. 11, 2014, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Technical Field 
     The present invention relates to a medical rehabilitation bed, belonging to the technical field of product structures of medical appliances, specifically belonging to the technical field of self-help rehabilitation bed structures in medical instrument products. 
     Description of Related Art 
     At present, various medical rehabilitation beds are commercially available on the market, the majority of which are structured to have fixed bed boards and bed stands. The height adjustment of beds is carried out with the bed stands by caretakers and family members. Traditional transmission mechanisms are heavy, labor-some and noisy, which directly or indirectly affects the treatment quality of patients. According to the physical conditions of patients and to the treatment requirements, patients need to sit upright or a certain part is needed to rise, for example, adjustment to the head or the feet. Therefore, a medical rehabilitation bed which is simple in adjustment, convenient and safe, and can be operated by patients themselves by their own requirements is needed. 
     SUMMARY OF THE INVENTION 
     Aiming at defects of the prior art, the present invention provides a medical rehabilitation bed to achieve the objectives of simple and excellent structure, safety in use, light weight, diversified and flexible functions. 
     To achieve the above objectives, the present invention employs the following technical solution: 
     A medical rehabilitation bed includes a bed head, a bed tail and a bed board, wherein a pull rod is arranged at the bottom of the bed board; the pull rod is rod-like with one end mechanically connected to a bed head gearbox which is arranged at the bed head, and the other end mechanically connected to a bed tail gear device which is arranged at the bed tail; transmission systems having the same structure and capable of controlling the bed head and the bed tail to ascend and descend are respectively arranged in the bed head and the bed tail; and the transmission systems are mechanically connected to the bed head gearbox and the bed tail gear device, respectively. 
     The bed head includes a bed stand, a bed head board, a bed head frame, roller bayonets, bayonets, connectors, connector dowel pins, lifting racks, roller fixing blocks and rollers. 
     The bed stand is a dual-leg upper-lower framework structure. The bed head frame is processed as a groove-shaped rigid lath structure, and is fixed at the upper border of the bed stand through plural bed head frame fixing screws. The upper border of the bed stand is a bottom-open groove-shaped structure. The lower border of the bed stand is a top-open groove-shaped structure. The two ends of the lower border are respectively in fastening connection with the two legs of the bed stand. The bed head board is a rigid plate structure, fixed at the upper and lower borders of the bed stand on two sides through plural bed head frame fixing screws. 
     Bed legs are hollow cylindrical rigid structures. A long hole is formed on the inner side of each of the bed legs. Each of the lifting racks is a hollow cylindrical rigid structure, formed with a long hole on the inner side, and inserted into a corresponding one of the bed legs from the bottom up. The upper end of each of the lifting racks pins and fixes a corresponding one of the connector pins at the end socket through a corresponding one of the connector dowel pins, and the lower end fixes a corresponding one of the roller fixing blocks at the end socket through a corresponding one of the roller bayonets. Each of the roller fixing blocks is connected with a corresponding one of the rollers. Each of the connector is provided with a bayonet which supports a corresponding one of the bed legs and performs a damping role, and the bayonet is a spring. 
     The bed tail and the bed head have the same structure. 
     A motor gear connecting box which is mechanically connected to a motor is disposed at the bottom of the bed board. The motor gear connecting box is provided with a coupling connector. The coupling connector is in a state of being connected or disconnected with the pull rod. 
     The bed tail gear device is a bed tail gearbox or a handle-containing bed tail gearbox. 
     In the state in which the coupling connector is connected with the pull rod, the motor drives the pull rod to rotate through the motor gear connecting box so that a structure is formed, in which the bed head gearbox and the bed tail gear device which are disposed at the bed head or bed tail drive the bed head or the bed tail to ascend and descend respectively through the transmission systems in mechanical connection. 
     Each one of the transmission systems includes a support rod, a support rod pin, an internal-thread lifting head limiting pin, a cap, a spiral lifting rod, a screw rod limiting pin, an internal-thread sleeve, an internal-thread lifting head, a steel cable fixing screw, fixed sleeves, a sleeve opening, a steel cable, a steel cable roller dowel pin and steel cable rollers. 
     The spiral lifting rod is positioned between the upper and lower borders of the bed stand in a vertical way, and is formed with an H-shaped cylindrical cap at the end socket of the upper end; the cap supports the upper border; the lower end of the spiral lifting rod passes through the lower border and is mechanically connected to the bed head gearbox or the bed tail gear device. 
     The internal-thread sleeve is a standing round tube structure, symmetrically formed with two rectangular through-holes on the side wall; the side wall below the through-holes integrally extends outward; and the extending portion is an overall rectangular plate structure which is vertical to the axis; the rectangular plate structure is formed with two through-holes A along one diagonal line, and is formed with two screw holes along another diagonal line; a through-hole B is disposed between each of the through-holes A and each of the screw holes; the diameter of each of the through-holes B is smaller than the diameter of the corresponding one of the screw holes, and the through-hole B communicates with the corresponding one of the screw holes. 
     Support rods parallel to the axis of the spiral lifting rod are respectively disposed on two sides of the spiral lifting rod; the support rods pass through the through-holes A; the two ends of each of the support rods are respectively connected with the upper and lower borders of the bed stand in a riveted way; the spiral lifting rod is fixed with two screw rod limiting pins; and the screw rod limiting pins are respectively positioned between the internal-thread sleeve and the cap and between the internal-thread sleeve and the end socket of the lower end of the spiral lifting rod. 
     The internal-thread lifting head is a standing round tube structure, respectively provided with screw threads on the inner and outer walls; the internal-thread lifting head is located in the internal-thread sleeve; the internal screw threads are in spiral connection with the spiral lifting rod; the internal-thread lifting head limiting pins are respectively disposed at the upper and lower end faces of the internal-thread lifting head; and the internal-thread lifting head limiting pins are parallel to the axis of the internal-thread lifting head. 
     The sleeve opening is an arc-shaped plate structure, having an inner wall provided with internal screw threads at a screw pitch which is the same as that of the external screw threads of the internal-thread lifting head. The sleeve opening is embedded in the rectangular through-hole of the internal-thread sleeve and is in spiral connection with the external screw threads of the internal-thread lifting head. 
     The fixed sleeves are semi-round plate structures, wrapping the excircles of the internal-thread sleeve and the sleeve opening in pairs and being fastened and connected to form a round tube structure. 
     The plural steel cable rollers are uniformly distributed in the groove-shaped structure of the lower border of the bed stand and are pinned and fixed with the lower groove-shaped border through steel cable roller dowel pins. 
     The steel cable bypasses plural steel cable rollers; one end of the steel cable is connected with the connector dowel pin in a locked way, and the end socket of the other end is connected with the steel cable fixing screw in a fastened way; the steel cable fixing screw passes through the screw hole in the rectangular plate structure and is clamped at the corresponding one of through-holes B. 
     A structure is formed, in which the internal-thread sleeve integrally moves up and down on the spiral lifting rod, driving the extension and withdrawal of the steel cable, and then driving the lifting racks to move up and down through the steel cable. 
     The bed head gearbox includes a female bed head gearbox housing, a male bed head gearbox housing, a large shaft bushing A, a first small shaft bushing A, a second small shaft bushing A, a third small shaft bushing A, a first bearing shim A, a second bearing shim A, a third bearing shim A, a fourth bearing shim A, a first plane bearing A, a second plane bearing A, a first spring shim A, a second spring shim A, an open-end short shaft A, a first dowel pin A, a second dowel pin A, a first bevel gear A, a second bevel gear A, a limiting shim A, a closed-end long shaft A and a split pin A. 
     The female bed head gearbox housing and the male bed head gearbox housing are respectively integrally molded by injection. The female bed head gearbox housing and the male bed head gearbox housing are internally provided with first convex and concave spaces which face each other and are used for clamping and fixing components. 
     The first bevel gear A and the second bevel gear A are positioned in the first convex and concave spaces, and are in mutually vertical arrangement and in engaged connection. 
     The open-end short shaft A is vertically disposed, with a lower end coupled and fixed with the first bevel gear A and an upper end formed with an open slot which is mechanically connected with the transmission systems; the open-end short shaft A is provided with the first dowel pin A which limits and locks the first bevel gear A; the open-end short shaft A is sequentially annularly sleeved in the large shaft bushing A, the first small shaft bushing, A, the first bearing shim A, the first plane bearing A, the second bearing shim A and the first spring shim A which are limited by the first convex and concave spaces from the top down; and the first bearing shim A and the first plane bearing A and the second bearing shim A and the first spring shim A and the first bevel gear A are in compact compression and connection. 
     The closed-end long shaft A is horizontally arranged, coupled and fixed with the second bevel gear A; the closed-end long shaft A is provided with the second dowel pin A which limits and locks the second bevel gear A; one end of the closed-end long shaft A passes through the limiting shim A and the second small shaft bushing A which are limited by the first convex and concave spaces, and extends out, and the end socket is provided with a splitting pin A for being connected with the pull rod; the other end of the closed-end long shaft A is sequentially annularly sleeved in the third small shaft bushing A, the fourth bearing shim A, the second plane bearing A, the third bearing shim A and the second spring shim A which are limited by the first convex and concave spaces from the right to the left; and, the fourth bearing shim A and the second plane bearing A and the third bearing shim A and the second spring shim A and the second bevel gear A are in compact compression and connection. 
     The handle-containing bed tail gearbox includes a female bed tail gearbox housing, a male bed tail gearbox housing, a large shaft bushing B, a first small shaft bushing B, a second small shaft bushing B, a third small shaft bushing B, a first bearing shim B, a second bearing shim B, a third bearing shim B, a fourth bearing shim B, a first plane bearing B, a second plane bearing B, a first spring shim B, a second spring shim B, an open-end short shaft B, a first dowel pin B, a second dowel pin B, a first bevel gear B, a second bevel gear B, a long shaft, a split pin B and a handle. 
     The female bed tail gearbox housing and the male bed tail gearbox housing are respectively integrally molded by injection. The female bed tail gearbox housing and the male bed tail gearbox housing are internally provided with second convex and concave spaces which face each other and are used for clamping and fixing components. 
     The first bevel gear B and the second bevel gear B are positioned in the second convex and concave spaces, and are in mutually vertical arrangement and in engaged connection. 
     The open-end short shaft B is vertically disposed, with a lower end coupled and fixed with the first bevel gear B and an upper end formed with an open slot which is mechanically connected with the transmission systems; the open-end short shaft B is provided with the first dowel pin B which limits and locks the first bevel gear B; the open-end short shaft B is sequentially annularly sleeved in the large shaft bushing B, the first small shaft bushing B, the first bearing shim B, the first plane bearing B, the second bearing shim B and the first spring shim B which are limited by the second convex and concave spaces from the top down; and the first bearing shim B and the first plane bearing B and the second bearing shim B and the first spring shim B and the first bevel gear B are in compact compression and connection. 
     The long shaft B is horizontally arranged, coupled and fixed with the second bevel gear B; the long shaft B is provided with the second dowel pin B which limits and locks the second bevel gear B; one end of the long shaft B passes through the third small shaft bushing B which is limited by the second convex and concave spaces, and extends out, and the end socket is provided with an open slot and is fixedly connected with the handle through the open slot. 
     The other end of the long shaft B is sequentially annularly sleeved in the second spring shim B, the fourth bearing shim B, the second plane bearing B, the third bearing shim B and the second small shaft bushing B which are limited by the second convex and concave spaces from the right to the left, and extends out of the second convex and concave spaces; the end socket of the other end of the long shaft B is provided with the split pin B for being connected with the pull rod; and the second spring shim B and the fourth bearing shim B and the second plane bearing B and the third bearing shim B and the second bevel gear B are in compact compression and connection. 
     The handle includes a handle fixing screw, a grip dowel pin, grip shims, a grip spring, a grip bolt, a grip and a grip connector; the handle wall of the handle is a cylindrical rigid structure; the end socket of one end of the handle wall is provided with an annular connecting portion in an integrated or fastened way; the grip connector is sunk in the annular connecting portion and is connected with the annular connecting portion in a fastened way through the handle fixing screw; and the end socket of the other end of the handle wall of the handle is formed with a groove or a recessed portion. 
     The grip connector is integrally columnar; one end is provided with a projecting portion; and the projecting portion is inserted in the open slot formed on the long shaft B and forms an interlocking structure. 
     The grip is a hollow cylindrical structure, internally inserted with the grip bolt. The grip bolt is annularly sleeved with the grip spring which is held by two grip shims. The end socket of one end of the grip bolt is inserted into the groove which is formed at the end socket of the other end of the handle wall of the handle and is connected in a riveted way through the grip dowel pin. The end socket of the other end of the grip bolt is provided with a limiting portion which limits the slide-out of the grip. 
     The bed tail gearbox includes a female bed tail gearbox housing, a male bed tail gearbox housing, a large shaft bushing C, a first small shaft bushing C, a second small shaft bushing C, a third small shaft bushing C, a first bearing shim C, a second bearing shim C, a third bearing shim C, a fourth bearing shim C, a first plane bearing C, a second plane bearing C, a first spring shim C, a second spring shim C, an open-end short shaft C, a first dowel pin C, a second dowel pin C, a first bevel gear C, a second bevel gear C, a long shaft C, a split pin C and a limiting shim C. 
     The female bed tail gearbox housing and the male bed tail gearbox housing are respectively integrally molded by injection. The female bed tail gearbox housing and the male bed tail gearbox housing are internally provided with second convex and concave spaces which face each other and are used for clamping and fixing components. 
     The first bevel gear C and the second bevel gear C are positioned in the second convex and concave spaces, and are in mutually vertical arrangement and in engaged connection. 
     The open-end short shaft C is vertically disposed, with a lower end coupled and fixed with the first bevel gear C and an upper end formed with an open slot which is mechanically connected with the transmission systems; the open-end short shaft C is provided with the first dowel pin C which limits and locks the first bevel gear C; the open-end short shaft C is sequentially annularly sleeved in the large shaft bushing C, the first small shaft bushing C, the first bearing shim C, the first plane bearing C, the second bearing shim C and the first spring shim C which are limited by the second convex and concave spaces from the top down; and the first bearing shim C and the first plane bearing C and the second bearing shim C and the first spring shim C and the first bevel gear C are in compact compression and connection. 
     The long shaft C is horizontally arranged, coupled and fixed with the second bevel gear C. The long shaft C is provided with the second dowel pin C which limits and locks the second bevel gear C. One end of the long shaft C passes through the limiting shim C and the third small shaft bushing C which are limited by the second convex and concave spaces, and has the end socket which is provided with an open slot. 
     The other end of the long shaft C is sequentially annularly sleeved in the second spring shim C, the fourth bearing shim C, the second plane bearing C, the third bearing shim C and the second small shaft bushing C which are limited by the second convex and concave spaces from the right to the left, and extends out of the second convex and concave spaces; the end socket of the other end of the long shaft C is provided with the split pin C for being connected with the pull rod; and the second spring shim C and the fourth bearing shim C and the second plane bearing C and the third bearing shim C and the second bevel gear C are in compact compression and connection. 
     The motor gear connecting box includes a female connecting box housing, a male connecting box housing, a short motor shaft, a coupling long shaft E, a first small shaft bushing E, a third small shaft bushing E, a first limiting shim E, a second limiting shim E, a first bevel gear E, a second bevel gear E, a first split pin E, a second split pin E, a first dowel pin E, a second dowel pin E, a first spring shim E, a third split pin E, a first bearing shim E, a second spring shim E, a first plane bearing E, a third bearing shim E, a second bearing shim E, a second plane bearing E, a second small shaft bushing E, a fourth bearing shim E, a fourth small shaft bushing E, a coupling connector spring and a coupling connector. 
     The female connecting box housing and the male connecting box housing are respectively integrally molded by injection. The female connecting box housing and the male connecting box housing are internally provided with third convex and concave spaces which face each other and are used for clamping and fixing components. 
     The first bevel gear E and the second bevel gear E are positioned in the third convex and concave spaces, and are in mutually parallel arrangement and in engaged connection. 
     The short motor shaft is horizontally arranged, coupled and fixed with the first bevel gear E; the short motor shaft is provided with the first dowel pin E which limits and locks the first bevel gear E. One end of the short motor shaft passes through the first limiting shim E and the first small shaft bushing E which are limited by the third convex and concave spaces, and extends out of the third convex and concave spaces, and the end socket is formed with a pin hole in which the first split pin E is inserted. The other end of the short motor shaft is sequentially annularly sleeved in the first spring shim E, the first bearing shim E, the first plane bearing E, the second bearing shim E and the second small shaft bushing E which are limited by the third convex and concave spaces from the left to the right. The first bevel gear E and the first spring shim E and the first bearing shim E and the first plane bearing E and the second bearing shim E are in compact compression and connection. 
     The coupling long shaft E is horizontally arranged, coupled and fixed with the second bevel gear E. The coupling long shaft E is provided with the second dowel pin E which limits and locks the second bevel gear E. One end of the coupling long shaft E passes through the second limiting shim E and the third small shaft bushing E which are limited by the third convex and concave spaces, and extends out of the third convex and concave spaces, and the end socket is formed with a pin hole in which the second split pin E is inserted. The other end of the coupling long shaft E is sequentially annularly sleeved in the second spring shim E, the third bearing shim E, the second plane bearing E, the fourth bearing shim E and the fourth small shaft bushing E which are limited by the third convex and concave spaces from the left to the right. The second bevel gear E and the second spring shim E and the third bearing shim E and the second plane bearing E and the fourth bearing shim E are in compact compression and connection; the other end of the coupling long shaft E extends and gets out of the third convex and concave spaces, and the end socket is formed with a pin hole in which the third split pin E is inserted. The coupling connector is an integrally hollow cylindrical structure which is square outside and round inside, having slot holes on the lateral side; one end of the coupling connector is inserted into the coupling long shaft E, and the other end is formed with a pin slot opening at the end socket. The coupling connector is in pin connection with the other end or right end of the coupling long shaft E through the third split pin E; and the coupling connector is internally provided with the coupling connector spring. 
     According to the technical solution of the present invention, the bed head and the bed tail are respectively provided with the bed head gearbox and the bed tail gearbox which are mechanically connected with transmission systems respectively disposed in the bed head or bed tail; meanwhile, the bed head gearbox and the bed tail gearbox are connected through a pull rod to form a entire transmission; when driven to rotate by a motor or a handle, the pull rod can bring bed feet which are connected with the transmission system to move vertically, thus realizing the vertical movement of the whole bed. The present invention has the advantages of compact structure, comprehensive functions, energy conservation, and flexible and convenient operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of an overall structure of the present invention; 
         FIG. 2  is a partially enlarged view of part A in a bed tail in  FIG. 1 ; 
         FIG. 3  is a partially enlarged view of part B in a bed head in  FIG. 1 ; 
         FIG. 4  is a schematic view of an appearance structure of the bed tail of the present invention; 
         FIG. 5 a    is a schematic view of an assembling structure of a lifting device of the present invention; 
         FIG. 5 b    is an exploded view of the structure of the lifting device of the present invention; 
         FIG. 5 c    is an exploded view of a partial structure of the lifting device of the present invention; 
         FIG. 6  is an exploded view of the structure of a bed head gearbox of the present invention; 
         FIG. 7  is an exploded view of the structure of a handle-containing bed tail gearbox of the present invention; 
         FIG. 7 a    is an exploded view of the structure of a handle portion in  FIG. 7 ; 
         FIG. 8  is an exploded view of the structure of a bed tail gearbox without a handle of the present invention; and 
         FIG. 9  is an exploded view of the structure of a motor gear connecting box of the present invention. 
       
         
           
                 
               
                 
                 
               
             
                 
                     
                 
                 
                   Description of marks in the drawings: 
                 
                 
                     
                 
               
               
                 
                     
                 
               
            
             
                 
                   101. Bed head gearbox 
                   102. Female bed head gearbox housing 
                 
                 
                   104. Large shaft bushing A 
                   103. Male bed head gearbox housing 
                 
                 
                   1051. First small shaft bushing A 
                   1052. Second small shaft bushing A 
                 
                 
                   1053. Third small shaft bushing A 
                   1061. First bearing shim A 
                 
                 
                   1062. Second bearing shim A 
                   1063. Third bearing shim A 
                 
                 
                   1064. Fourth bearing shim A 
                   1071. First plane bearing A 
                 
                 
                   1072. Second plane bearing A 
                   1081. First spring shim A 
                 
                 
                   1082. Second spring shim A 
                   109. Open-end short shaft A 
                 
                 
                   1101. First dowel pin A 
                   1102. Second dowel pin A 
                 
                 
                   1111. First bevel gear A 
                   1112. Second bevel gear A 
                 
                 
                   112. Limiting shim A 
                   113. Closed-end long shaft A 
                 
                 
                   114. Split pin A 
                   201. Handle-containing bed tail gearbox 
                 
                 
                   202. Female bed tail gearbox housing 
                   203. Male bed tail gearbox housing 
                 
                 
                   204. Large shaft bushing B 
                   2051. First small shaft bushing B 
                 
                 
                   2052. Second small shaft bushing B 
                   2053. Third small shaft bushing B 
                 
                 
                   2061. First bearing shim B 
                   2062. Second bearing shim B 
                 
                 
                   2063. Third bearing shim B 
                   2064. Fourth bearing shim B 
                 
                 
                   2071. First plane bearing B 
                   2072. Second plane bearing B 
                 
                 
                   2081. First spring shim B 
                   2082. Second spring shim B 
                 
                 
                   209. Open-end short shaft B 
                 
                 
                   2101. First dowel pin B 
                   2102. Second dowel pin B 
                 
                 
                   2111. First bevel gear B 
                   2112. Second bevel gear B 
                 
                 
                   212. Long shaft B 
                   213. Split pin B 
                 
                 
                   223. Handle fixing screw 
                   224. Handle 
                 
                 
                   225. Grip dowel pin 
                   226. Grip shim 
                 
                 
                   227. Grip spring 
                   228. Grip bolt 
                 
                 
                   229. Grip 
                   230. Grip connector 
                 
                 
                   301. Bed tail gearbox 
                   304. Large shaft bushing C 
                 
                 
                   3051. First small shaft bushing C 
                   3052. Second small shaft bushing C 
                 
                 
                     
                   3053. Third small shaft bushing C 
                 
                 
                   3061. First bearing shim C 
                   3062. Second bearing shim C 
                 
                 
                   3063. Third bearing shim C 
                   3064. Fourth bearing shim C 
                 
                 
                   3071. First plane bearing C 
                   3072. Second plane bearing C 
                 
                 
                   3081. First spring shim C 
                   3082. Second spring shim C 
                 
                 
                   309. Open-end short shaft C 
                 
                 
                   3101. First dowel pin C 
                   3102. Second dowel pin C 
                 
                 
                   3111. First bevel gear C 
                   3112. Second bevel gear C 
                 
                 
                   312. Long shaft C 
                   313. Split pin C 
                 
                 
                   314. Limiting shim C 
                 
                 
                   401. Transmission system 
                 
                 
                   402. Bed head board 
                   403. Bed head frame 
                 
                 
                   404. Roller bayonet 
                   405. Bayonet 
                 
                 
                   406. Connector 
                   407. Connector dowel pin 
                 
                 
                   408. Lifting rack 
                   409. Roller fixing block 
                 
                 
                   410. Roller 
                   411. Bed head frame fixing screw 
                 
                 
                   412. Support rod 
                   413. Support rod pin 
                 
                 
                   414. Internal-thread lifting head limiting pin 
                   415. Cap 
                 
                 
                   416. Spiral lifting rod 
                   417. Screw rod limiting pin 
                 
                 
                   418. Internal-thread sleeve 
                 
                 
                   420. Internal-thread lifting head 
                   421. Steel cable fixing screw 
                 
                 
                   422. Fixed sleeve 
                   423. Sleeve opening 
                 
                 
                   424. Steel cable 
                   425. Steel cable roller fixing pin 
                 
                 
                   426. Steel cable roller 
                   501. Motor gear connecting box 
                 
                 
                   502. Female connecting box housing 
                   503. Male connecting box housing 
                 
                 
                   504. Short motor shaft 
                   505. Coupling long shaft E 
                 
                 
                   5041. First small shaft bushing E 
                   5051. Third small shaft bushing E 
                 
                 
                   5042. First limiting shim E 
                   5052. Second limiting shim E 
                 
                 
                   5043. First bevel gear E 
                   5053. Second bevel gear E 
                 
                 
                   5044. First split pin E 
                   5054. Second split pin E 
                 
                 
                   5045. First dowel pin E 
                   5055. Second dowel pin E 
                 
                 
                   5046. First spring shim E 
                   5056. Third split pin E 
                 
                 
                   5047. First bearing shim E 
                   5057. Second spring shim E 
                 
                 
                   5048. First plane bearing E 
                   5058. Third bearing shim E 
                 
                 
                   5049. Second bearing shim E 
                   5059. Second plane bearing E 
                 
                 
                   50410. Second small shaft bushing E 
                   50510. Fourth bearing shim E 
                 
                 
                   50511. Fourth small shaft bushing E 
                   506. Coupling connector spring 
                 
                 
                   507. Coupling connector 
                   601. Motor 
                 
                 
                     
                 
               
            
           
         
       
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The technical solution of the present invention is described below in further detail in accompanying with the attached drawings. 
     As shown in  FIGS. 1, 2, 3 and 4 , a medical rehabilitation bed includes a bed head, a bed tail and a bed board, wherein a pull rod is arranged at the bottom of the bed board. The pull rod can be arranged at the center of the bottom of the bend board. The pull rod is a rod-like structure or a solid rod-like structure, with one end mechanically connected to a bed head gearbox  101  which is arranged at the bed head, and the other end mechanically connected to a bed tail gear device which is arranged at the bed tail. Transmission systems  401  having the same structure and capable of controlling the bed head and the bed tail to ascend and descend are respectively arranged in the bed head and the bed tail. The transmission systems  401  are mechanically connected to the bed head gearbox  101  and the bed tail gear device, respectively. The bed tail gear device is a bed tail gearbox  301  or a handle-containing bed tail gearbox  201 . 
     The bed head includes a bed stand  428 , bed head board  402 , a bed head frame  403 , roller bayonets  404 , bayonets  405 , connectors  406 , connector dowel pin  407 , lifting racks  408 , roller fixing blocks  409  and rollers  410 . 
     The bed stand  428  is a dual-leg upper-lower framework structure. The bed head frame  403  is processed as a groove-shaped rigid lath structure (namely a bottom-open groove-shaped structure which is formed by bending two ends at an angle of 90 DEG toward the same direction along the same lateral face of the lath), and is fixed at the upper border  429  of the bed stand  428  through plural bed head frame fixing screws  411 .. The upper border  429  of the bed stand  428  is a bottom-open groove-shaped structure (or the cross section of the upper border  429  is a bottom-open groove-shaped structure). The lower border of the bed stand  428  is a top-open groove-shaped structure (or the cross section of the lower border is a top-open groove-shaped structure). The two ends of the lower border are respectively in fastening connection (for example, welded connection) with the two legs  427  of the bed stand  428 . The bed head board  402  is a rigid plate structure, fixed at the upper and lower borders of the bed stand  428  on two sides through plural bed head frame fixing screws  411 . 
     Bed legs  427  are hollow cylindrical rigid structures. A long hole is formed on the inner side of each of the bed legs  427 . Each of the lifting racks  408  is a hollow cylindrical rigid structure, formed with a long hole on the inner side, and inserted into a corresponding bed leg  427  such that the long hole of the bed leg  427  and the long hole of the lifting rack are positioned on the same side and run through each other. The upper end of each of the lifting racks  408  pins and fixes a corresponding one of the connectors  406  at the end socket through a corresponding one of the connector dowel pins  407 , and the lower end fixes a corresponding one of the roller fixing blocks  409  at the end socket through a corresponding one of the roller bayonets  404 . Each of the roller fixing blocks  409  is connected with a corresponding one of the rollers  410 . Each of the connectors  406  is provided with a bayonet  405  which supports a corresponding one of the bed legs  427  (inner side) and performs a damping role, and the bayonet  405  is a spring. 
     The bed tail and the bed head have the same structure. 
     A motor gear connecting box  501  which is mechanically connected to a motor  601  is disposed at the bottom of the bed board. The motor  601  can be fixed at the bottom of the bed board. The motor gear connecting box  501  is provided with a coupling connector  507 . The coupling connector  507  is in a state of being connected or disconnected with the pull rod, which means that, by such configuration, the motor can be used to drive the pull rod to rotate (namely connected state), or the motor is not used to drive the pull rod to rotate (namely the disconnected state), and the handle is rotated to drive the pull rod to rotate. 
     In the state in which the coupling connector  507  is connected with the pull rod, the motor  601  drives the pull rod to rotate through the motor gear connecting box  501  so that a structure is formed, in which the bed head gearbox  101  and the bed tail gear device which are disposed at the bed head or bed tail drive the bed head or the bed tail to ascend and descend respectively through the transmission systems  401  in mechanical connection. 
     As shown in  FIGS. 5 a , 5 b  and 5 c   , each one of the transmission systems  401  includes a support rod  412 , a support rod pin  413 , an internal-thread lifting head limiting pin  414 , a cap  415 , a spiral lifting rod  416 , a screw rod limiting pin  417 , an internal-thread sleeve  418 , an internal-thread lifting head  420 , a steel cable fixing screw  421 , fixed sleeves  422 , a sleeve opening  423 , a steel cable  424 , a steel cable roller dowel pin  425  and steel cable rollers  426 . 
     The spiral lifting rod  416  is positioned between the upper and lower borders of the bed stand  428  in a vertical way, and is formed with an H-shaped cylindrical cap  415  at the end socket of the upper end. The cap  415  supports or supports and fixes the upper border  429 . The lower end of the spiral lifting rod  416  passes through the lower border  430  and is mechanically connected to the bed head gearbox  101  or the bed tail gear device, for example mechanical coupling connection. 
     The internal-thread sleeve  418  is a standing round tube structure, symmetrically formed with two rectangular or square through-holes on the side wall; the side wall below the through-holes integrally extends outward; and the extending portion is an overall rectangular plate structure which is vertical to the axis of the internal-thread sleeve  418 . The rectangular plate structure is formed with two through-holes A  432  along one diagonal line (which means that the rectangular plate structure is provided with two through-holes A  432  which are symmetric to the diagonal line), and is formed with two screw holes  431  along another diagonal line. A through-hole B  433  is disposed between each one of the through-holes A  432  and each one of the screw holes  431 . In this way, the two symmetric sides of the rectangular plate structure respectively have a through-hole A  432 , a through-hole B  433  and a screw hole. The diameter of each of the through-holes B  433  is smaller than the diameter of the corresponding one of the screw holes  431 , and the through-hole B  433  communicates with the corresponding one of the screw holes  431 . The purpose of such configuration is as follows: the steel cable fixing screw  421  which is fixed at the steel cable  424  passes through the larger screw hole and then enters the smaller through-hole B  433  via a channel which communicates with the screw hole such that the steel cable fixing screw  421  is clamped and fixed at the through-hole B  433 , and then a screw is screwed into the screw hole to fasten the steel cable fixing screw  421  without slipping; further speaking, such structure firmly fixes the steel cable  424  at the internal-thread sleeve  418 . 
     Support rods  412  parallel to the axis of the spiral lifting rod  416  are respectively disposed on two sides of the spiral lifting rod  416 . The support rods  412  pass through the through-holes A  432 . The two ends of each of the support rods  412  are respectively connected with the upper and lower borders  430  of the bed stand  428  in a riveted way. One purpose of configuring the support rods  412  is to strengthen the overall firmness of the spiral lifting rod  416 , and the other purpose is to provide the support rods  412  as guide columns, which facilitates the vertical movement of the internal-thread sleeve  418  on the spiral lifting rod  416  to play a supporting function. The spiral lifting rod  416  is fixed with two screw rod limiting pins  417 . The screw rod limiting pins  417  are respectively positioned between the internal-thread sleeve  418  and the cap  415  and between the internal-thread sleeve  418  and the end socket of the lower end of the spiral lifting rod  416 . Actually, the upper and lower two screw rod limiting pins  417  disposed at the spiral lifting rod  416  play the role of limiting the upper dead point position and lower dead point position when the internal-thread sleeve  418  moves on the spiral lifting rod  416 . 
     The internal-thread  420  is a standing round tube structure, respectively provided with screw threads on the inner and outer walls. The internal-thread lifting head  420  is located in the internal-thread sleeve  418 . The internal screw threads are in spiral connection with the spiral lifting rod  416 . Internal-thread lifting head limiting pins  414  are respectively disposed at the upper and lower end faces of the internal-thread lifting head  420 . The internal-thread lifting head limiting pins  414  are parallel to the axis of the internal-thread lifting head  420 . The internal-thread lifting head limiting pins  414  are disposed in a way of protruding the upper end face or lower end face of the internal-thread lifting head  420 . When the internal-thread lifting head limiting pin  414  at the upper end face moves to the upper dead point position along with the internal-thread sleeve  418 , the screw rod limiting pin  417  disposed at the upper part stops the rotation of the internal-thread lifting head limiting pin  414 , further stopping the upward movement of the internal-thread sleeve  418 . Likewise, when the internal-thread lifting head limiting pin  414  at the lower end face moves to the lower dead point position along with the internal-thread sleeve  418 , the screw rod limiting pin  417  disposed at the lower part stops the rotation of the internal-thread lifting head limiting pin  414 , further stopping the downward movement of the internal-thread sleeve  418 . 
     The sleeve opening  423  is an arc-shaped plate structure, having an inner wall provided with internal screw threads at a screw pitch which is the same as that of the external screw threads of the internal-thread lifting head  420 . The sleeve opening  423  is embedded in the rectangular through-hole of the internal-thread sleeve  418  and is in spiral connection with the external screw threads of the internal-thread lifting head  420 . 
     The fixed sleeves  422  are semi-round plate structures, wrapping the excircles of the internal-thread sleeve  418  and the sleeve opening  423  in pairs and being fastened and connected (for example through welding) to form a round tube structure. 
     The plural steel cable rollers  426  are uniformly distributed in the groove-shaped structure of the lower border  430  of the bed stand  428  and are pinned and fixed with the lower groove-shaped border through steel cable roller dowel pins  425 . For example, two steel cable rollers  426  are respectively disposed on each one of the left and right sides of a spiral lifting center  416  which serves as the center, and the external two steel cable rollers  426  are located at positions of the lower border  430  respectively connected with a bed leg  427 , as shown in  FIG. 5   b.    
     The steel cable  424  bypasses plural steel cable rollers  426 , gets in via the long holes formed on the inner sides of each bed leg  427  and each corresponding lifting rack  408 ; one end (getting in the holes) of the steel cable is connected with the connector dowel pin  407  in a locked way, and the end socket of the other end is connected with the steel cable fixing screw  421  in a fastened way. The steel cable fixing screw  421  passes through the screw hole in the rectangular plate structure and is clamped at the corresponding one of through-holes B  433 . 
     A structure is formed, in which the internal-thread sleeve  418  integrally moves up and down on the spiral lifting rod  416 , driving the extension and withdrawal of the steel cable  424 , and then driving the lifting racks  408  to move up and down through the steel cable  424 . 
     As shown in  FIG. 6 , the bed head gearbox  101  includes a female bed head gearbox housing  102 , a male bed head gearbox housing  103 , a large shaft bushing A 104 , a first small shaft bushing A 1051 , a second small shaft bushing A 1052 , a third small shaft bushing A 1053 , a first bearing shim A 1061 , a second bearing shim A 1062 , a third bearing shim A 1063 , a fourth bearing shim A 1064 , a first plane bearing A 1071 , a second plane bearing A 1072 , a first spring shim A 1081 , a second spring shim A 1082 , an open-end short shaft A 109 , a first dowel pin A 1101 , a second dowel pin A 1102 , a first bevel gear A 1111 , a second bevel gear A 1112 , a limiting shim A 112 , a closed-end long shaft A 113  and a split pin A 114 . 
     The female bed head gearbox housing  102  and the male bed head gearbox housing  103  are respectively integrally molded by injection, and after being folded, can enclose components inside to prevent slipping and misalignment. The female bed head gearbox housing  102  and the male bed head gearbox housing  103  are internally provided with first convex and concave spaces which face each other and are used for clamping and fixing components. 
     The convex and concave spaces refer to the interiors of the female bed head gearbox housing  102  and the male bed head gearbox housing  103  which are internally molded by injection according to the external size of each of the components to be limited such that the corresponding components are embedded therein, thus fulfilling the aim of fixing the components; the second convex and concave spaces and the third convex and concave spaces mentioned later are the same as the first convex and concave spaces and therefore are not further described. 
     The first bevel gear A 1111  and the second bevel gear A 1112  are positioned in the first convex and concave spaces, and are in mutually vertical arrangement and in engaged connection. 
     The so called mutually vertical (the first bevel gear A 1111  and the second bevel gear A 1112 ) arrangement and engaged connection refers to that the axes of the two bevel gears are vertical to each other and that the teeth of the bevel portions of the two bevel gears are mutually engaged. The mutually vertical arrangement and engaged connection of the first bevel gear B and the second bevel gear B and that of the first bevel gear C and the second bevel gear C are in a similar way. 
     The open-end short shaft A 109  is vertically disposed, with a lower end coupled and fixed with the first bevel gear A 1111  and an upper end formed with an open slot which is mechanically connected with the transmission systems  401 . The open-end short shaft A 109  is provided with the first dowel pin A 1101  which limits and locks the first bevel gear A 1111 . The open-end short shaft A 109  is sequentially annularly sleeved in the large shaft bushing A 104 , the first small shaft bushing A 1051 , the first bearing shim A 1061 , the first plane bearing A 1071 , the second bearing shim A 1062  and the first spring shim A 1081  which are limited by the the first convex and concave spaces from the top down. 
     The above top-to-bottom sequential loop overlapping is achieved in this way: the large shaft bushing A 104  is closest to the upper open slot, below followed by the first small shaft bushing A 1051 , the first bearing shim A 1061 , the first plane bearing A 1071 , the second bearing shim A 1062  and the first spring shim A 1081  in turn. 
     The first bearing shim A 1061  and the first plane bearing A 1071  and the second bearing shim A 1062  and the first spring shim A 1081  and the first bevel gear A 1111  are in compact compression and connection, representing that the five components can rotate synchronously (along with the open-end short shaft A 109 ), which means that the first convex and concave spaces respectively independently limit the large shaft bushing A 104  and the first small shaft bushing A 1051 , as shown in  FIG. 6 . 
     The closed-end long shaft A 113  is horizontally arranged, coupled and fixed with the second bevel gear A 1112 . The closed-end long shaft A 113  is provided with the second dowel pin A 1102  which limits and locks the second bevel gear A 1112 . One end (for example, left end) of the closed-end long shaft A 113  passes through the limiting shim A 112  and the second small shaft bushing A 1052  which are limited by the first convex and concave spaces, and extends out, and the end socket is provided with the split pin A 114  for being connected with the pull rod. The other end (for example, right end) of the closed-end long shaft A 113  is sequentially annularly sleeved in the third small shaft bushing A 1053  (the third small shaft bushing A 1053  is positioned at the most right end), the fourth bearing shim A 1064 , the second plane bearing A 1072 , the third bearing shim A 1063  and the second spring shim A 1082  which are limited by the first convex and concave spaces from the right to the left. The fourth bearing shim A 1064  and the second plane bearing A 1072  and the third bearing shim A 1063  and the second spring shim A 1082  and the second bevel gear A 1112  are in compact compression and connection, which means that the five components can synchronize with the closed-end long shaft A 113  during rotation. The first convex and concave spaces independently limit the third small shaft bushing A 1053 , as shown in  FIG. 6 . The small shaft bushing independently limited in the corresponding convex and concave spaces as shown in  FIGS. 7, 8 and 9  can be explained and understood in a similar way. The corresponding large shaft bushing is also independently limited. 
     As shown in  FIG. 7  and  FIG. 7 a   , the handle-containing bed tail gearbox  201  includes a female bed tail gearbox housing  202 , a male bed tail gearbox housing  203 , a large shaft bushing B 204 , a first small shaft bushing B 2051 , a second small shaft bushing B 2052 , a third small shaft bushing B 2053 , a first bearing shim B 2061 , a second bearing shim B 2062 , a third bearing shim B 2063 , a fourth bearing shim B 2064 , a first plane bearing B 2071 , a second plane bearing B 2072 , a first spring shim B 2081 , a second spring shim B 2082 , an open-end short shaft B 209 , a first dowel pin B 2101 , a second dowel pin B 2102 , a first bevel gear B 2111 , a second bevel gear B 2112 , a long shaft B 212 , a split pin B 213  and a handle  224 . 
     The female bed tail gearbox housing  202  and the male bed tail gearbox housing  203  are respectively integrally molded by injection. The female bed tail gearbox housing  202  and the male bed tail gearbox housing  203  are internally provided with second convex and concave spaces which face each other and are used for clamping and fixing components. 
     The first bevel gear B 2111  and the second bevel gear B 2112  are positioned in the second convex and concave spaces, and are in mutually vertical arrangement and in engaged connection. 
     The open-end short shaft B 209  is vertically arranged, with a lower end coupled and fixed (for example by means of interference fixing, others concerning coupling and fixing can be explained in this way) with the first bevel gear B 2111  and an upper end formed with an open slot which is mechanically connected with the transmission system  401 . The open-end short shaft B 209  is provided with the first dowel pin B 2101  which limits and locks the first bevel gear B 2111 . The open-end short shaft B 209  is sequentially annularly sleeved in the large shaft bushing B 204 , the first small shaft bushing B 2051 , the first bearing shim B 2061 , the first plane bearing B 2071 , the second bearing shim B 2062  and the first spring shim B 2081  which are limited by the second convex and concave spaces from the top down (the large shaft bushing B 204  is on the top, and the large shaft bushing B 204  and the first small shaft bushing B 2051  are respectively independently limited by the second convex and concave spaces. The so called limiting can be explained as position limiting). The first bearing shim B 2061  and the first plane bearing B 2071  and the second bearing shim B 2062  and the first spring shim B 2081  and the first bevel gear B 2111  are in compact compression and connection, which means that the five components (including the first bevel gear B 2111 ) synchronize with the open-end short shaft B 209  during rotation. 
     The long shaft B 212  is horizontally arranged, coupled and fixed with the second bevel gear B 2112 . The long shaft B 212  is provided with the second dowel pin B 2102  which limits and locks the second bevel gear B 2112 . One end (or right end) of the long shaft B 212  passes through the third small shaft bushing B 2053  which is limited by the second convex and concave spaces, and extends out, and the end socket is provided with an open slot and is fixedly connected with the handle  224  through the open slot. 
     The other end (left end) of the long shaft B 212  is sequentially annularly sleeved in the second spring shim B 2082 , the fourth bearing shim B 2064 , the second plane bearing B 2072 , the third bearing shim B 2063  and the second small shaft bushing B 2052  which are limited by the second convex and concave spaces from the right to the left, and extends out of the second convex and concave spaces, which means that the second small shaft bushing B 2052  is positioned at the most left end of the five components. The end socket of the other end (left end) of the long shaft B 212  is provided with the split pin B 213  for being connected with the pull rod. The second spring shim B 2082  and the fourth bearing shim B 2064  and the second plane bearing B 2072  and the third bearing shim B 2063  and the second bevel gear B 2112  are in compact compression and connection, which means that the five components (the second spring shim B 2082 , the fourth bearing shim B 2064 , the second plane bearing B 2072 , the third bearing shim B 2063  and the second bevel gear B 2112 ) can synchronize with the long shaft B 212  during rotation. The second small shaft bushing B 2052  is independently limited by the second convex and concave spaces. 
     As shown in  FIG. 7 a   , the handle  224  includes a handle fixing screw  223 , a grip dowel pin  225 , grip shims  226 , a grip spring  227 , a grip bolt  228 , a grip  229  and a grip connector  230 . The handle wall of the handle  224  is a cylindrical rigid structure; the end socket of one end of the handle wall is provided with an annular connecting portion in an integrated or fastened way. The grip connector  230  is sunk in the annular connecting portion and is connected with the annular connecting portion in a fastened way through the handle fixing screw  223 . The end socket of the other end of the handle wall of the handle  224  is formed with a groove or a recessed portion. 
     The grip connector  230  is an integrally cylindrical or solid column; one end is provided with a projecting portion; and the projecting portion is inserted in the open slot formed on the long shaft B 212  and forms an interlocking structure. 
     The grip  229  is a hollow cylindrical structure, internally inserted with the grip bolt  228 . The grip bolt  228  is annularly sleeved with the grip spring  227  which is held by two grip shims  226 . The end socket of one end of the grip bolt  228  is inserted into the groove or recession portion which is formed at the end socket of the other end of the handle wall of the handle  224  and is connected in a riveted way through the grip dowel pin  225 . The end socket of the other end of the grip bolt  228  is provided with a limiting portion which limits the slide-out of the grip  229 . In this way, when the grip  229  is rocked, the projecting portion formed on the grip connector  230  is inserted into the open slot of the long shaft B 212  and forms an interlocking to drive the long shaft B 212  to rotate, thus driving the transmission system  401  to ascend and descend the bed head or bed tail through the bevel gear. 
     As shown in  FIG. 8 , the bed tail gearbox  301  includes a female bed tail gearbox housing  202 , a male bed tail gearbox housing  203 , a large shaft bushing C 304 , a first small shaft bushing C 3051 , a second small shaft bushing C 3052 , a third small shaft bushing C 3053 , a first bearing shim C 3061 , a second bearing shim C 3062 , a third bearing shim C 3063 , a fourth bearing shim C 3064 , a first plane bearing C 3071 , a second plane bearing C 3072 , a first spring shim C 3081 , a second spring shim C 3082 , an open-end short shaft C 309 , a first dowel pin C 3101 , a second dowel pin C 3102 , a first bevel gear C 3111 , a second bevel gear C 3112 , a long shaft C 312 , a split pin C 313  and a limiting shim C 314 . 
     The female bed tail gearbox housing  202  and the male bed tail gearbox housing  203  are respectively integrally molded by injection. The female bed tail gearbox housing  202  and the male bed tail gearbox housing  203  are internally provided with second convex and concave spaces which face each other and are used for clamping and fixing components. The structure of the bed tail gearbox is identical with the structure of the handle-containing bed tail gearbox. 
     The first bevel gear C 3111  and the second bevel gear C 3112  are positioned in the second convex and concave spaces, and are in mutually vertical arrangement and in engaged connection. 
     The open-end short shaft C 309  is vertically arranged, with a lower end coupled and fixed with the first bevel gear C 3111  and an upper end formed with an open slot which is mechanically connected with the transmission system  401 . The open-end short shaft C 309  is provided with the first dowel pin C 3101  which limits and locks the first bevel gear C 3111 . The open-end short shaft C 309  is sequentially annularly sleeved in the large shaft bushing C 304 , the first small shaft bushing C 3051 , the first bearing shim C 3061 , the first plane bearing C 3071 , the second bearing shim C 3062  and the first spring shim C 3081  which are limited by the second convex and concave spaces from the top down. The large shaft bushing C 304  is positioned on the top of the open-end short shaft C 309 . The large shaft bushing C 304  and the first small shaft bushing C 3051  are respectively independently limited by the second convex and concave spaces. The first bearing shim C 3061  and the first plane bearing C 3071  and the second bearing shim C 3062  and the first spring shim C 3081  and the first bevel gear C 3111  are in compact compression and connection, which means that the five components (the first bearing shim C 3061 , the first plane bearing C 3071 , the second bearing shim C 3062 , the first spring shim C 3081  and the first bevel gear C 3111 ) synchronize with the open-end short shaft C 309  during rotation. 
     The long shaft C 312  is horizontally arranged, coupled and fixed with the second bevel gear C 3112 . The long shaft C 312  is provided with the second dowel pin C 3102  which limits and locks the second bevel gear C 3112 . One end (right end) of the long shaft C 312  passes through the limiting shim C 314  and the third small shaft bushing C 3053  which are limited by the second convex and concave spaces, and the end socket is provided with an open slot. 
     The other end (left end) of the long shaft C 312  is sequentially annularly sleeved in the second spring shim C 3082 , the fourth bearing shim C 3064 , the second plane bearing C 3072 , the third bearing shim C 3063  and the second small shaft bushing C 3052  which are limited by the second convex and concave spaces from the right to the left, and extends out of the second convex and concave spaces, which means that the second small shaft bushing C 3052  is positioned at the most left end. The end socket of the other end (left end) of the long shaft C 312  is provided with the split pin C 313  for being connected with the pull rod. The second spring shim C 3082  and the fourth bearing shim C 3064  and the second plane bearing C 3072  and the third bearing shim C 3063  and the second bevel gear C 3112  are in compact compression and connection, which means that the five components (the second spring shim C 3082 , the fourth bearing shim C 3064 , the second plane bearing C 3072 , the third bearing shim C 3063  and the second bevel gear C 3112 ) can synchronize with the long shaft C 312  during rotation. The second small shaft bushing C 3052  is independently limited by the second convex and concave spaces. 
     As shown in  FIG. 9 , the motor gear connecting box  501  includes a female connecting box housing  502 , a male connecting box housing  503 , a short motor shaft  504 , a coupling long shaft E 505 , a first small shaft bushing E 5041 , a third small shaft bushing E 5051 , a first limiting shim E 5042 , a second limiting shim E 5052 , a first bevel gear E 5043 , a second bevel gear E 5053 , a first split pin E 5044 , a second split pin E 5054 , a first dowel pin E 5045 , a second dowel pin E 5055 , a first spring shim E 5046 , a third split pin E 5056 , a first bearing shim E 5047 , a second spring shim E 5057 , a first plane bearing E 5048 , a third bearing shim E 5058 , a second bearing shim E 5049 , a second plane bearing E 5059 , a second small shaft bushing E 50410 , a fourth bearing shim E 50510 , a fourth small shaft bushing E 50511 , a coupling connector spring  506  and a coupling connector  507 . 
     The female connecting box housing  502  and the male connecting box housing  503  are respectively molded by injection. The female connecting box housing  502  and the male connecting box housing  503  are internally provided with third convex and convex spaces which face each other and are for clamping and fixing components. Here, the so called convex and concave spaces (or the third convex and concave spaces) refer to the interiors of the female connecting box housing  502  and the male connecting box housing  503  which are internally molded by injection with molds according to external sizes or partial external sizes of components to be limited such that the corresponding components can be embedded therein, thus fulfilling the aim of fixing or limiting the components when the female connecting box housing  502  and the male connecting box housing  503  are folded. 
     The first bevel gear E 5043  and the second bevel gear E 5053  are positioned in the third convex and concave spaces, and are in mutually parallel arrangement and in engaged connection. 
     The so called (the first bevel gear E 5043  and the second bevel gear E 5053 ) mutually parallel arrangement and engaged connection is that the axes of the two bevel gears are parallel (for example, the directions of teeth of the bevel portions of the two bevel gears are the same, as shown  FIG. 9 ) and that the teeth of the non-bevel portions of the two bevel gears are mutually engaged. 
     The short motor shaft  504  is horizontally arranged, coupled and fixed with the first bevel gear E 5043 . The short motor shaft  504  is provided with the first dowel pin E 5045  which limits and locks the first bevel gear E 5043 . One end (or left end) of the short motor shaft  504  passes through the first limiting shim E 5042  and the first small shaft bushing E 5041  which are limited by the third convex and concave spaces, and extends out of the third convex and concave spaces, and the end socket is formed with a pin hole in which the first split pin E 5044  is inserted. The other end (or right end) of the short motor shaft  504  is sequentially annularly sleeved in the first spring shim E 5046 , the first bearing shim E 5047 , the first plane bearing E 5048 , the second bearing shim E 5049  and the second small shaft bushing E 50410  which are limited by the third convex and concave spaces from the left to the right (which means that the second small shaft bushing E 50410  is positioned at the most right end or outer end). The first bevel gear E 5043  and the first spring shim E 5046  and the first bearing shim E 5047  and the first plane bearing E 5048  and the second bearing shim E 5049  are in compact compression and connection, which means that the five components (the first bevel gear E 5043 , the first spring shim E 5046 , the first bearing shim E 5047 , the first plane bearing E 5048  and the second bearing shim E 5049 ) synchronize with the short motor shaft E 504  during rotation. The second small shaft bushing E 50410  is independently limited by the third convex and concave spaces without projection. 
     The coupling long shaft E 505  is horizontally arranged, coupled and fixed with the second bevel gear E 5053 . The coupling long shaft E 505  is provided with the second dowel pin E 5055  which limits and locks the second bevel gear E 5053 . One end (left end) of the coupling long shaft E 505  passes through the second limiting shim E 5052  and the third small shaft bushing E 5051  which are limited by the third convex and concave spaces, and extends out of the third convex and concave spaces, and the end socket is formed with a pin hole in which the second split pin E 5054  is inserted. The other end (right end) of the coupling long shaft E 505  is sequentially annularly sleeved in the second spring shim E 5057 , the third bearing shim E 5058 , the second plane bearing E 5059 , the fourth bearing shim E 50510  and the fourth small shaft bushing E 50511  which are limited by the third convex and concave spaces from the left to the right. The fourth small shaft bushing E 50511  is positioned at the most right end or outer end of the five components, and is independently limited by the third convex and concave spaces. The second bevel gear E 5053  and the second spring shim E 5057  and the third bearing shim E 5058  and the second plane bearing E 5059  and the fourth bearing shim E 50510  are in compact compression and connection, which means that the five components (the second bevel gear E 5053  and the second spring shim E 5057  and the third bearing shim E 5058  and the second plane bearing E 5059  and the fourth bearing shim E 50510 ) synchronize with the coupling long shaft E 505  during rotation. The other end (right end) of the coupling long shaft E 505  extends and gets out of the third convex and concave spaces, and the end socket is formed with a pin hole in which the third split pin E 5056  is inserted. The coupling connector  507  is an integrally hollow cylindrical structure which is square outside and round inside, having slot holes on the lateral side; one end of the coupling connector is inserted into the coupling long shaft E 505 , and the other end is formed with a pin slot opening at the end socket. The coupling connector  507  is in pin connection with the other end or right end of the coupling long shaft E 505  through the third split pin E 5056 . The coupling connector  507  is internally provided with the coupling connector spring  506 .