We give voice to our TECH TEAM.
By LORENZO CALVI Technical Director
How we designed an isostatic solution for MB108
What we had to design:
A gearbox that could be adapted to an existing system in a large shopping center in Switzerland.
What was the challenge:
we had to study an isostatic machine to be inserted in a Niche-frame in a low-lateral position with ropes direction upwards. The overall dimensions were very particular, extremely large.
The difficulty was given by the considerable distance between the center of the pulley (and therefore of the load) with respect to the center line of the support depending on the 8 tons supported.
What we have achieved.
We have designed an MB108 gearbox (the largest in the Sassi range) with a special slow shaft almost 1 meter long. The particular constructive shape of this machine has allowed us to design the internal position of the worm-wheel at a symmetrical distance from the bearings with respect to the external position of the load given by the system (distance between the sheave center and the support equal to 250mm).
Despite these measures, the whole construction is ISOSTATIC, therefore on two supports: one is clearly visible on the frame and is a Ø135mm bearing, the other one is internal to the machine and has a diameter of 170mm.
This solution has allowed us to obtain better fatigue safety coefficients than other construction solutions.
The frame itself, while designed according to the constraints imposed by the customer, is sized as an integral part of the gearbox's basement in order to increase its stiffness and its resistance under maximum load.
This machine is therefore a "unicum" designed to give the best on that system, a definetly "tailor-made" solution with power and load levels beyond the average.
MACHINE : gearbox MB108
STATIC LOAD : 8000kg
TRAVEL : 30m
ROPES DIRECTION : upwards
DUTY LOAD : 4t
POWER : 45Kw
MOTOR B3 : 4 poles VF Nidec – IE3
For further information:
visit the MB108 page - click here