Need A Low Speed Gearbox For A Small Electric Motor

Need a slow speed gear box, where the output shaft must be turned by a worm gear. No backlash allowed. Output shaft speed must be between 0.4 and 0.6 rpm. Rated output torque 6000kg/cm. Input speed 4000rpm. 12 or 24V DC motor, max. current 8A will be used to drive it, can be supplied with the gearbox. If supplied, the motor must have either provisions for, or installed a shaft sensor providing one or two TTL level pulse(s) per revolution,

The gearbox must work in the temperature range of -40 to +40 degrees (C) and require no maintenance. Moisture and dust sealed output shaft. There are no compliance requirements - this is a new application.

This is to be used in a X-Y positioner, where one motor turns a turret about a vertical axis, the other turns the payload about a horizontal axis. Both motors/gearboxes shall be mounted on the turret, with output shafts perpendicular.There will be no other mechanical parts within the turret, design must accomodate motors and gearboxes in a space-saving manner. Both X and Y gearboxes/motors need not be identical, one solution is to design the turret as a housing for both motors and all gears, if gear lubrication is not necessary.

Several design approaches have been considered, however there are no specific requirements as to number and material of gears. Any question - please ask.