Patent ID: 6213906
Filing Date: 2001-04-10
Classification: B25J,Y10T

Abstract:
A device for supporting and pivoting an arm (10) which can swing about a vertical axis (A) and has a working head (12) at a free end of the type comprising:a fixed structure (42),a hollow pillar (14) rotatable about the vertical axis (A) and supporting the arm (10),a reversible electric motor (88) having a casing fixed to the fixed structure (42) and an output shaft (90) concentric with the vertical axis (A), anda mechanical reduction transmission which interconnects the output shaft (90) of the motor (88) and the pillar (14) and includes a pair of reduction units (62, 64),characterized in thatboth reduction units (62, 64) of the mechanical transmission are of the planetary type, each with a driving member (94), a driven member (68, 70), a fixed peripheral ring (72, 74), and internal gearing,the driving members (94) of both reduction units (62, 64) are fixed angularly to the output shaft (90) of the motor (88),the driven members (68, 70) of both reduction units (62, 64) are fixed angularly to the pillar (14),when the device is in operation, the peripheral rings (72, 74) of both reduction units (62, 64) are fixed to the fixed structure (42),the angular position of at least one of the peripheral rings (72) is adjustable about the vertical axis (A) relative to the other ring (74) to enable the play in the internal gearing of the reduction units (62, 64) to be cancelled out,the hollow pillar (14) is fixed on a platform (50) mounted for rotating about the vertical axis (A) on the fixed structure (42),the fixed structure (42) is substantially C-shaped in cross-section with a lower plate-like portion (44) and an upper flange-like portion (48) interconnected by a lateral yoke (46),the platform (50) comprises an annular peripheral portion (52) and a spoke (58) extending radially inwardly with an end portion constituting a flange (60) centred on the vertical axis (A),the spoke (48) and its flange (60) are interposed between the two lower and upper portions (44, 48) of the fixed structure,the motor (88) is supported centrally in the hollow pillar (14) on the upper portion (48) of the fixed structure (42),the rings (72, 74) of the two reduction units (62, 64) are fixed to the upper and lower portions (48, 44) of the fixed structure (42), respectively, andthe driven members (68, 70) of both reduction units (62, 64) are fixed to the flange-like end portion (60) of the platform (50).