Multi-shaft electrically-operated automatic nut runner

A multi-shaft electrically-operated automatic nut runner capable of simultaneously rotating a plurality of wheel-mounting nuts, comprising:

• a plurality of sockets shaped to correspond to a shape of said wheel-mounting nuts, said sockets having a pitch circle diameter equal to a pitch circle diameter of said wheel-mounting nuts, a pitch of said sockets on the pitch circle thereof being equal to a multiple of an integer of a pitch of said wheel-mounting nuts on the pitch circle thereof;
• a plurality of transmitting members, said sockets being fixed to said transmitting members;
• a plurality of driving means for driving said sockets, wherein a rotational driving force is imparted in both a forward direction and a reverse direction by means of an electrical power source, said transmitting members being coupled for rotation to said driving means;
• a plurality of torque-generating rotating members rotatably coupled to said transmitting members, said torque-generating rotating members being coupled for rotation to said driving means;
• a plurality of torque-changing means each disposed between a corresponding one of said plurality of torque-generating rotating members and a corresponding one of said plurality of transmitting members for changing a torque of the rotational driving force from said torque-generating rotating members to said transmitting members;
• a plurality of stoppers each disposed for engagement with a corresponding one of said plurality of torque-generating rotating members, said stopper members being movable between a projected and a retracted position, said stoppers simultaneously interrupting rotation of said torque-generating rotating members in the projected position at which each of said stoppers projects into a range of movement of a corresponding one of said plurality of torque-generating rotating members, said stoppers in said retracted position simultaneously allowing said torque-generating rotating members to resume rotation, wherein when rotation of said torque-generating rotating members is interrupted, said torque of the rotational driving force is changed to said transmitting members by said torque changing means, said torque having a first predetermined value or less during free rotation of said torque-generating rotating members and a second predetermined value higher than said first predetermined value when rotation of said torque-generating rotating members is interrupted by said stopper means;
• driver means coupled to said stoppers for simultaneously moving said stoppers to and from said retracted position;
• and
• a control switch electrically connected to said driver means, said control switch actuating said driver means to move said stoppers to and from said retracted position.