Motovated Case Studies

SCS Ripper Gearbox Design 

Background:

Screening and Crushing Systems (SCS) approached Motovated Design & Analysis to help in the expansion and development of their Vertical Shaft Cutter (VSC) Ripper line.

The patented Orbital Action of the VSC Cutting Chamber (Figure 2) combined with good engineering and clear thinking during the initial design had allowed subsequent expansion from the first 200 HP plant up to 400 HP. However, expanding the capacity further was proving difficult – the flexible chain drive was proving to be a   limiting factor.

The design constraints and specifications to be met were:

  • Increase the input horsepower to 500 HP.
  • Maintain the tip speed and orbit diameter of the unit. These were highlighted as Key Performance Criteria through extensive testing, which needed to be maintained to ensure the consistently high performance of the VSC product range.
  • Accommodate the increased loads within the space available.

Peter Suckling, the General Manager of SCS, initiated a round table discussion between all their suppliers to develop some conceptual solutions.

The Solution:

Duralloy Gears Ltd confirmed one of SCS’s solutions in the form of a gear train concept to replace the chain drive, while Motovated and SAECO Bearings analysed the shafts and bearings, to verify they could take the increased loads (Figure 3).

Motovated was also employed to help with the CAD modelling, to maintain the tight timelines as well as to ensure best practice CAD standards were maintained. A full set of manufacturing and assembly drawings were provided.

An additional advantage provided to Motovated by SCS was the option of a clear sheet concept approach. This provided the flexibility to use Motovated’s extensive experience in stress minimisation to design the shafts and gear train with advanced analysis.

The Result:

SCS has once again managed to maintain the key performance criteria which allow the VSC Ripper line to perform Best-In-Class, while increasing the rotor diameter and input horsepower as required to support market demands.

They managed this all while minimising their required development and prototype time, by including suppliers up-front in the conceptual stages, as well as engaging them in the ongoing design. This allowed SCS to expand their already significant engineering capacity as needed.

Motovated SCS Ripper Gearbox Design Case Study
SCS Ripper Cutting Chamber Designed by Motovated
Ripper Gearbox View CAD Model by Motovated

Figure 2: Section view of the Ripper CAD model.

Stress plots of the rotor drive shaft & spaces analyzed by Motovated