Industrial robot of the articulated type

An industrial robot of the articulated type comprising:

• a parallelogram linkage of rigid members composed of a first brachium, a forearm, a lever and a second brachium;
• wherein said first brachium and said lever form a first pair of members and are rotatably supported on a shoulder, said shoulder having a first brachium drive motor and a forearm drive motor mounted thereon;
• wherein said first brachium is connected to an output shaft of said first brachium drive motor through a first reducing gearing in such a manner that rotational output motion of the first brachium drive motor is transmitted to said first brachium exclusively by rotational movements;
• and
• wherein said lever is connected to an output shaft of said forearm drive motor through a second reducing gearing in such a manner that rotational output motion of the forearm drive motor is transmitted to said lever exclusively by rotational movements;
• and
• a wrist, and first and second wrist drive motors connected to said wrist for varying the posture thereof, said first and second wrist drive motors being mounted on a first connection between said lever and said second brachium in a manner for serving as a counterbalance means.

An industrial robot of the articulated type, comprising:

• a swivelling pedestal mounted movably at a vertical center axis on a base;
• a first brachium supported at a lower end thereof for pivotal movement about a first axis disposed horizontally on said swivelling pedestal;
• a lever supported for pivotal movement about said first axis;
• a second brachium pivotally connected at one end thereof to an end of said lever for pivotal movement about a second axis;
• a forearm pivotally connected to an opposite end of said second brachium for movement about a third axis and being pivotally connected to an upper end of said first brachium for movement with respect to said first brachium about a fourth axis, a quadric parallel motion mechanism thereby being formed by said first brachium, said lever, said second brachium and a portion of said forearm between said third and fourth axes, said forearm having a second portion extending from the upper end of said first brachium, away from said quadric parallel motion mechanism;
• a wrist mounted at an extended end of said second portion of the forearm;
• a first brachium drive motor;
• a first drive means for pivotally moving said first brachium, said first drive means being mounted on said first brachium at said first axis perpendicularly to a plane of said quadric parallel motion mechanism and connected to said first brachium drive motor in such a manner that the angle of rotation of said first brachium is directly proportional to the angle of rotation of said first brachium drive motor;
• a forearm drive motor;
• and
• a second drive means for pivotally moving said forearm via said second brachium by pivotally moving said lever, said second drive means being mounted on said lever at said first axis perpendicularly to the plane of said quadric parallel motion mechanism and connected to said forearm drive motor in such a manner that the angle of rotation of said forearm is directly proportional to the angle of rotation of said forearm drive motor;
• whereby the moment applied to said quadric motion mechanism about said first axis can be minimized to directly drive said first brachium and said lever by said drive motors.