Group 2 Gate 5
The product dissected was an Eager Beaver chainsaw by McCulloch. This product was sold for household use and was developed in Arizona in 1988. It uses a gasoline internal combustion engine to power a chain, which is the mechanism that cuts the tree or limb. We analyzed how the design was affected by various factors. By reverse engineering each of the chainsaw's subsystems, we discovered how each system provides its own function while contributing to the main goal of the whole system, which is the removal of tree branches or trees.
The disassembly of this product was done very carefully and precisely with lots of pictures and documentation to ensure that it would be able to be reassembled properly. We were quite surprised to see how durable the design of this device was. All of the inside components were coated with a dark, thick layer of sludge from multiple decades of use and yet the components all worked together seamlessly. Any components that were vulnerable to malfunction were sealed in casings.
We also found that there were some outdated factors of this chainsaw which is to be expected since it was designed over 20 years ago. One of the most important aspects of the chainsaw that we found to be outdated was also one of the most simple aspects. The metal handle had very little consideration to comfort or ease of use for the user. We realized that this would be a simple, cheap, and effective revision to the product.
Product Analysis Summary
The analysis process for the Eager Beaver Chainsaw mostly consisted of the dissection and reverse engineering of the product and its subsystems.
While dissecting the product into its several subsystems and then components, we were able to gain a better perspective on how the chainsaw itself is able to function. This being said, the group already knew a good amount about the functionality of chainsaws so not too much of what we were seeing was foreign to us. A complete, in depth description of the product dissection can be viewed in GATE 2.
The analysis of this product took the form of several different models as seen in Gate 3 more comprehensively. Every component was removed, examined, labeled and documented into a table. We then determined information on each component such as manufacturing method and number of times it was used in the design.
CAD models were made of several of the most essential components and a working model was assembled of several of the moving parts. Below is a video rendering of the working CAD model. Video Renderings
Piston Video 1 is a video showing the piston head reciprocating back and forth while the crankshaft is rotated from the piston's movement.
Piston Video 2 is a video of the same setup but cutting the system in half. This easily shows how the connector rod and the counterweight from the crankshaft come close to the piston head's walls. It also provides a simplification of the system from a system in three dimensions to a system of two dimensions.
Both videos go through three cycles.
This chainsaw was designed in 1988 so it is not free of flaws. Today there are several changes that could be made to the design to make it much more user friendly as well as more environmentally friendly. In this section we discussed what we believed could be beneficial to add to the chainsaw. Changes included an ergonomic rubber grip handle as well as safety and comfort changes. A more in depth description of these changes can be found in Gate 3 and 4.
- ergonomic rubber grip handle
- safety revisions for the blade
- quieter muffler
- comfort changes
A more in depth description of these changes can be found in Gate 3 and 4.