Abstract: A tractor assembly includes a connection unit which is connected between the tractor and the wheel chair. The connection unit includes a fixing member, a top link unit, a bottom link unit and a swing rod so as to form a four-link mechanism. The connection unit includes an engaging unit with an engaging section, and a position unit. The top link unit has a reception hole and the positioning unit has a push rod. When the push rod is located at the first position, the reception hole is closed. When the push rod is located at the second position, the push rod is retracted and the reception hole is exposed. The bottom link unit is pivoted about one end of the swing rod to move the other end of the swing rod to the position of the reception hole, the engaging section is inserted into the reception hole.

Abstract: A tractor assembly includes a connection unit which is connected between the tractor and the wheel chair. The connection unit includes a fixing member, a top link unit, a bottom link unit and a swing rod so as to form a four-link mechanism. The connection unit includes an engaging unit with an engaging section, and a position unit. The top link unit has a reception hole and the positioning unit has a push rod. When the push rod is located at the first position, the reception hole is closed. When the push rod is located at the second position, the push rod is retracted and the reception hole is exposed. The bottom link unit is pivoted about one end of the swing rod to move the other end of the swing rod to the position of the reception hole, the engaging section is inserted into the reception hole.

Abstract: The purpose of this invention is to enhance the stability of seat up-down adjustment and the aesthetics of a wheelchair. The mechanism is structured by the cart frame, the seat, the linking rod mechanism and the linear motion actuator. There are at least two linking rod mechanisms, each mechanism is composed of several connecting frames and pivot-linked with each others and remains two distal ends for connecting to the cart frame and the seat. The linear motion actuator connects the cart frame and the seat, moves the seat up and down smoothly with help from the stable supporting of the linking rod mechanism. The whole adjustment mechanism is confined in between the seat and the cart frame, which minimizes the needed space and makes a nice figure.

Abstract: The purpose of this invention is to enhance the stability of seat up-down adjustment and the aesthetics of a wheelchair. The mechanism is structured by the cart frame, the seat, the linking rod mechanism and the linear motion actuator. There are at least two linking rod mechanisms, each mechanism is composed of several connecting frames and pivot-linked with each others and remains two distal ends for connecting to the cart frame and the seat. The linear motion actuator connects the cart frame and the seat, moves the seat up and down smoothly with help from the stable supporting of the linking rod mechanism. The whole adjustment mechanism is confined in between the seat and the cart frame, which minimizes the needed space and makes a nice figure.