JPS6464994A - Crab trolley crane with expansion beam - Google Patents

Abstract

PURPOSE: To increase the speed of rise and fall of equipment by connecting a first beam and a third beam to a coupling chain pivotally supported to a second beam and inverted by a rotating wheel. CONSTITUTION: When a screw shaft 13 is rotated by actuating a motor 15, a second beam 7 rises or falls relative to a first beam 6, and a sprocket 18 rises or falls with the rise or fall of the second beam 7, while a third beam 8 rises or falls by the same amount as and in the same direction as the rise or fall of the second beam 7 and the sprocket 18 relative to the first beam 6. Therefore, the third beam 8 rises or falls relative to the first beam 6 at a speed twice the speed of rise or fall of the second beam 7 relative to the first beam 6. Similarly, when a screw 23 is rotated by actuating a motor 25, a fifth beam 10 rises or falls relative to the third beam 8 at a speed twice the speed of rise or fall of a fourth beam 9 relative to the third beam 8. This constitution allows the fifth beam 10 to rise or fall at a speed four times that of the second beam 7 when the motors 15, 25 are operated in synchronization, whereby the speed of rise and fall of equipment 12 can be increased.