International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The following paper reviews all the possible cases of coupled two-carrier planetary gears with four external shafts. An emphasis is made on the work of these gears with one degree of freedom, one input and one output shaft and brakes on the other two shafts . When switching over the gears, the speed ratio of the gear is changed, thus allowing the use in two-speed mechanical transmissions of technological lifting and other machines. Some relations are deduced for determining the speed ratios and the efficiency of all structural schemes.
Recommendations for the selection of the most appropriate structural scheme according to the current necessities can be made. A 3D model of the S13V3 two-speed, two-carrier gearbox was created to demonstrate the process of determining the viability of a particular gearbox layout.

Clamshell cranes are hoisting machines (machines with cyclic action) designed for handling bulk materials. The name of these cranes comes from the load gripping device – clamshell grab. In addition to the clamshell (two-jaw) grab for bulk materials, there are grabs designed for long-size and single loads. In the case of high-productivity bulk materials handling, double-rope clamshells are most suitable, which require a specialized clamshell crane with two hoisting mechanisms. The article discusses a reducer for a crane hoisting mechanism with an embedded planetary gear train (PGT), allowing the two ropes to move together, at the same speed, as well as independently of each other, or together at different speeds. The different modes of operation of the mechanism are considered. An analysis of the possible kinematic schemes of the PGT is made. The necessary kinematic calculations are made to select the most suitable variant of the PGT.

In addition to the universal requirements for handling (lifting and transport) machines (HM), HM for dangerous goods (hot molten metal, containers with chemicals, explosives, etc.) must also meet a number of special requirements. One of these requirements is the drive of the hoisting mechanism with two motors, to ensure in case one of them fails.
The article discusses a reducer for the hoisting mechanism of an overhead crane for dangerous goods with an embedded planetary gear train, allowing both motors to operate at full power (and without overload) in both regular and emergency (in failure) mode. The different modes of work of the mechanism are considered (with both motors and with each one separately). An analysis of the possible kinematic schemes of the planetary gear train is made. The necessary kinematic calculations have been made to select the most suitable variant of the planetary gear train.

The article reviews the requirements for the lifting mechanisms of cranes according to various regulations concerning dangerous goods. Particular attention is paid to these requirements regarding gear trains. Some design solutions for providing microspeed as well as for twin-motor drive are discussed. These arrangements are suitable for both lifting and travel mechanisms. A kinematic analysis was made and recommendations were given to the designers.