Drive specialist Rollstar takes torque to the extreme
An automotive gearbox creates a torque of around 500 Newton metres. A planetary gearbox from Rollstar takes this up to 6.5 million. That’s enough to drill a hole through the Gotthard or save the Tower of Pisa.
Leonardo da Vinci had already begun grappling with torque when he tried – famously unsuccessfully – to create a perpetual motion machine. And smart sports car fans prefer to brag about high torque rather than horsepower. Torque is a physical parameter that can be used to turn the world upside down. For the Swiss family business Rollstar AG, it is at the heart of everything they do.
Rollstar’s designers are passionate gearbox and engine manufacturers, but they are in a different league from, for example, the engine manufacturers in the automotive industry. Their planetary gearboxes work with torques of up to 6,500,000 Newton metres and perform heavy-duty work in tunnel boring machines – such as that used for the Gotthard Base Tunnel – in track construction, shipbuilding, ropeway construction and numerous other applications. They are often used in conjunction with Rollstar hydraulic motors. A prime example of the wide range of possible applications is the operation of a hydrostatic transmission engine on an earth drilling rig that was used to stabilise the Leaning Tower of Pisa.
Swiss precision for the world market
Rollstar sees itself as a niche supplier that, in keeping with the tradition of Swiss industry, focuses not on the mass market but on consistency in terms of quality and precision. The company controls virtually the entire manufacturing process: all of the work steps except for heat treatment are carried out in-house. «However, we don’t just need to be better than the competition,» says Christian Märki, Purchasing Manager and Member of the Extended Executive Board, «but also faster.»
Modular production concept for high flexibility
To achieve this goal, they organise their production according to the modular principle. Large stocks of pre-produced standard components and the high flexibility of the design based on modern CAD systems and FE calculation shorten the manufacturing process and guarantee short delivery times. Rollstar also steps on the gas when a gearbox or engine fails: the service team carries out standard repairs within five working days. Spare parts from the standard programme are available worldwide no later than 72 hours after receiving the order.
Procurement also runs smoothly
In addition to Parker Legris pneumatic components, Rollstar regularly purchases Turck inductive sensors from Bachofen. These permanently measure the number of revolutions in the planetary gearboxes, monitor the shift position or determine the operating status of the brake. The decision in favour of Turck was based on demand from customers, but the purchasing department and the engineers at Rollstar are more than happy with it. The product has won them over with its quality. And as far as their supply partner Bachofen is concerned, they appreciate the reliability, the high availability of products, the open communication and the competitive prices.