Robot arm with multiple-connection interface

A robot arm, comprising:

• a proximal unit;
• and
• a distal unit configured to be connected to the proximal unit,
• the proximal unit including a connection interface connectable to a plurality of types of distal units different in shape, wherein
• the connection interface is directly connectable to every one of a plurality of types of speed reducers different in shape,
• the distal unit is connectable to the proximal unit via the speed reducer,
• the connection interface includes a first, inner interface and a second, outer interface disposed concentrically with the first, inner interface,
• the first, inner interface comprises a plurality of first fastening portions disposed circumferentially at a first interval in an end face of the proximal unit,
• the second, outer interface comprises a plurality of second fastening portions disposed circumferentially at a second interval in the end face of the proximal unit,
• the first interval of the first fastening portions is different from the second interval of the second fastening portions,
• the first, inner interface is directly connectable to a first type of speed reducer having a first shape, and the second, outer interface is directly connectable to a second type of speed reducer having a second shape, and
• the connection interface further includes a mating portion fitted with the distal unit, and the mating portion is an annular protrusion formed by the second, outer interface protruding from the first, inner interface.

A robot arm, comprising:

• a proximal unit including a plurality of first connection interfaces different from each other;
• a plurality of distal units each having a second connection interface;
• and
• a plurality of speed reducers each having a third connection interface, and a fourth connection interface opposite the third connection interface in an axial direction of said each speed reducer, wherein
• the proximal unit is directly connectable to every one of the plurality of speed reducers,
• the third connection interfaces of the plurality of speed reducers are different from each other,
• the robot arm has a plurality of configurations different from each other,
• in one configuration among the plurality of configurations,
• one first connection interface among the plurality of first connection interfaces of the proximal unit is directly, detachably connected to the third connection interface of one speed reducer among the plurality of speed reducers, and
• the fourth connection interface of the one speed reducer is directly, detachably connected to the second connection interface of one distal unit among the plurality of distal units, and
• in a further configuration among the plurality of configurations,
• a further first connection interface among the plurality of first connection interfaces of the proximal unit is directly, detachably connected to the third connection interface of a further speed reducer among the plurality of speed reducers,
• the fourth connection interface of the further speed reducer is directly, detachably connected to the second connection interface of a further distal unit among the plurality of distal units, and
• the proximal unit further includes a mating portion to be fitted with the plurality of speed reducers, and the mating portion is formed by an outer first connection interface among the plurality of first connection interfaces protruding from an inner first connection interface among the plurality of first connection interfaces.