This report represents the bachelor thesis examination by Julia Kastehelmi Rintamäki. The examination has been performed during spring semester 2013 at Volvo Construction Equipment in Eskilstuna. This report, Development of parking brake component, describes the product development process of the parking brake component for articulated hauler, wheel loader and grader. Volvo CE has problems with the parking brake switch that exist today on articulated hauler, wheel loader and grader. The purpose of this project is to develop one common solution for the parking brake component for articulated hauler, wheel loader and grader. The secondary purpose is to find final concept proposal for each machine. Employees at the Volvo CE were interviewed; they were contacted via e-mail, phone calls and via meetings to get the information about the machines and the information around the parking brake component. Volvo CE databases were also used for gathering information about standards and pictures. Lots of different ideas were sketched and concept proposals were created with the aid of material from marketing analysis, competitor analysis, target group analysis, requirement specification, function analysis, standards and ergonomics. Eight concept proposals were chosen to be evaluated with QFD, Pugh’s matrix and FMEA. Two concepts were most suitable and developed further to three dimensional models with the aid of Solid Works. The different aspects were taken into account when designing and dimensioning the final concepts. Two models were created with the aid of plasticine for figuring out the ergonomics and dimensions of the product. DFM, DFA, DFE, D4S were used for taking into account costs, assembly, dimensions and environmental impacts of this product. One of the concepts could replace the existing parking brake switch and suit in different cabins because of its size and design. This concept can be located on vertical or on horizontal plane. The other final concept solution functions better for the  articulated hauler on account of the double function with exhausting brake system activating before parking brake system. Suggestion for next steps for the project could be to make prototypes of the two concepts and test these components in real machines. Also interviewing users for further development of the final concepts and redesign if needed.

Failure of a parked unattended vehicle to remain stationary, otherwise known as vehicle rollaway, can result in property damage, injury or even fatality. Although the incidence of vehicle rollaway may be under reported, around 8% of drivers and 13% of Approved Driving Instructors surveyed indicated they had experienced a vehicle rollaway event. Unlike previous studies which focused only on the mechanical factors that may contribute to this phenomenon, the research presented in this thesis employed a more comprehensive, systems approach to explore additional factors related to the driver s interaction with the parking brake system at various interface levels. A mixed methods strategy collated data through two online surveys and three observational studies to explore the organisational, mechanical and driver related factors identified in a fault tree framework. The results indicated that current driver practice and interaction with the parking brake system may be contrary to legislative requirements and manufacturer s instruction. The findings suggested that a past experience of vehicle rollaway or parking brake system failure, had a statistically significant influence on whether the driver complied with the recommended practice. Driver interaction and the holding capability of the parking brake system were observed in 53 vehicles parked on three test gradients. The observations indicated that drivers were able to apply sufficient force to the parking brake lever to hold the vehicle stationary and that an additional degree of confidence in the system was provided by parking in gear. But, after driving a short commuting route, when the vehicle was parked with the parking brake lever applied to the lowest position to hold the vehicle and a gear was not selected, 63% of vehicles fitted with disc brakes rolled as the temperature returned to ambient. Discussion relates to the organisational, driver related and mechanical components of the parking brake system and in reference to Reason s Swiss Cheese model, considers how latent failures within the defensive layers of the system can contribute to rollaway. The research findings contributed to a change in UK driving standards and since 2015, drivers are recommended to park in gear at all times to reduce the risk of rollaway. This recommendation is likely to require a change in practice for up to 80% of Approved Driving Instructors who would not normally instruct new drivers in this way. Although this research focused on the manually operated parking brake system, the studies have uncovered results that can contribute to knowledge and are applicable to interaction with electronic parking brake systems. As parking brake systems develop, the Human Factors systems approach can be applied retrospectively and proactively to explore that interaction and prevent passenger vehicle rollaway.

This master’s thesis is deal with the design of the tractor’s front axle drive to enlarge its braking efficiency of the standing tractor fixed by the parking brake. In the first two chapters, the basic information related to the above stated issue is being summarized. Next, procedure of creating the design including the fundamental calculation proposal is being described. In the last chapter, the strain-stress analysis of the selected partial sections of the design is being presented. The final design is supported with the drawing documentation that is being part of this master’s thesis, too.