Crampons are a device composed of a framework containing prongs, a front-part binding and a rear-part binding system that are attached to the boots in order to climb through steep walls covered by ice, snow or rocks.
Currently, the process to attach the binding system is complicated and time consuming. A new design of the rear-part binding system of the step-in crampon adapted to the current boot is therefore desired to create.
The Five-Step Method is implemented to obtain the concept design. The refinement of the concept is then performed and the mechanism is designed based on the action of a spring.
This improvement provides a simpler and faster attachment process to the boot and it does not require removing the gloves. The steps for the new fastening and unfastening process are lowered compared to the step-in crampon. The Value Engineering Method is used when establishing the materials and manufacturing process of the components.
Chromoly steel AISI 4130 is determined for the most critical components suffering highest stresses. High Density Polyethylene polymer is used for the parts with the lowest demands concerning the stresses they have to bear. These materials stand extremely low temperatures and provide low density and high tensile strength. Commercial elements are used when possible to reduce the costs and simplify the design and assembly process.
A CNC milling machine is used to manufacture the steel pieces with simple shape. The moulding process for steels is established for the steel components with more complicated shapes. Injection moulding is determined to produce the polymer parts. A simple and effective process is established for the assembly of the elements, which does not required high ability or specific tools. The design of the assembly provides the opportunity to recycle the materials.
The functionality of the attachment mechanism is proved. It is verified that the critical components withstand the stresses created at them according to a security factor of 4. This is concluded accomplishing an analytical analysis and also using the Finite Element Method. The cost of the new product is estimated to be more expensive than the reference step-in crampon.
The designed product weights almost the same than the current step-in crampon and it has reduced dimensions for storing it. It includes a security system that avoids the binding system being released even if a high force is applied to the system. It is important to regulate the binding system to the height of the rear-part groove of the boot and to fasten the security system tightly to avoid any clearances between the boot and the crampon.
Source: University of Skövde
Author: Sukia Garmendia, Alex | Echaniz Granado, Iñigo
>> Mechanical Engineering Projects based on Mechanics for Final Year Students