Group 22 - Black & Decker Alligator Lopper

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Black and Decker Alligator Lopper Electric Chainsaw.



Alexander M.
Keerthi K.
Spencer K.
Allicia G.
Zachery W.



Our group for MAE 277 had the opportunity to familiarize ourselves with the corded Black and Decker Alligator Lopper. This particular device is a branch cutting and trimming device designed for homeowners and the upkeep of their property. It utilizes the technology of an electric powered chainsaw while incorporating a jaw which the user can manipulate open and close. When the user wants to cut a branch, they manipulate the handles and expose the chainsaw to the branch. By clamping the jaws shut around the branch, the user forces the chainsaw into the branch, cutting it. Through the product dissection, we learned that the Lopper was designed with a high level of safety which can be seen in its dual trigger system. Furthermore, most of the product was intended to be taken apart for maintenance or part replacement. This is illustrated in both the simplicity with which the Lopper was designed and also in the list of components the user may purchase online. Further analysis of the product gave us the impression that the components were manufactured using simple techniques that can support a high production rate. Furthermore the materials used in building the Lopper indicate that it was intended to be used in residential areas and would not withstand prolonged commercial use. Assembling the product reaffirmed our belief that the user was supposed to access and maintain most internal components. It also showed us that the product could be modified easily to improve its function and form. These modifications range from small subsystem modifications to larger full system revisions.

Project Gates

Gate One


In our group's attempt to further understand the inner mechanisms of our multi-purpose Alligator Lopper hand tool, we plan to perform reverse engineering and deconstruct the equipment to reveal its moving internal parts and subsystem interactions. Once we obtain the actual product, we can further examine its exterior and make assumptions about its limitations as far as movement, accessibility, and other similar characteristics. However, the bulk of our project requires us to disassemble the product. Based on pictures we have viewed online, we anticipate that we will use a wrench or socket set for the two main exterior bolts, Phillips screwdrivers will be required for the outer housing, and a set of allen wrenches could be of significant use when dismantling the subsystems within the housing. During the deconstruction process, we plan to arrange the disassembled parts in an ordered fashion documenting their purpose and its placement within the product's systems. This will make an easier task of reassembling the product after our dissection. Our group seems to be strong in understanding the technical workings of this piece of equipment based on photographs seemingly due to previous experience with lawn care devices. At least one of us has used a chainsaw a few times in their life so that experience and understanding will come in handy when trying to reverse engineer this product.

Explore here ---> Gate 1

Gate Two


During the course of this gate the group will disassemble the Alligator Lopper. The group will observe the different aspects of the Alligator Lopper during the dissection of the product, which allows them to obtain a clearer understanding of the subsystems and the interactions between components. Every stage of dissection will have its own level of difficulty to which the group will categorize and create a rubric representing each step. Some of the factors which will determine the difficulty ratings are the tools that are used disassemble the product in each step.

One of the other major focuses of this gate is to determine the subsystems within the product and observe the interaction between them. Group need to analyze the inputs and outputs of the energy flows that will be represented by different arrows in diagrams for subsystems. In addition to the subsystem diagram the subsystem is should explained in detail.

The factors of what impact the subsystem connections should also be considered within this gate, providing specific examples of global, environmental, societal and economical factors.

Explore here ---> Gate 2

Gate Three


In this stage of the project, the group will use the previously dissected components hidden within the subsystems to gather more detailed information about the product. Rather than looking at the flows and functions of the overall subsystems, such as the chainsaw, or the motor, the group will analyzed the components of those systems by specifying the functionality, process in which the component were created from, and flows that go in and out of those components. Added to the analysis of the components, the group will provide 3 Dimensional models of the components that exist within the subsystems.

The group will examine key components or functions of the system, and explain how engineering analysis would be used in the design or testing stages of the design process. They will apply relevantly common equations and processes that would allow an engineer to easily perform this analysis. The final task at hand is following through with the engineering analysis to perform design revisions for at least three components of the subsystem level. The group is allowed to change, combine, or eliminate components, and express global, societal, economic, or environmental concerns regard said changes. The changes should improve performance, serviceability, cost, and other such properties of the product.

Explore here ---> Gate Three

Gate Four


In this stage of the Project, the group will reassemble their product as a means of acquiring more detailed information regarding its functionality and properties that will be used for students to create a conclusion about their overall product. The groups will share any unresolved challenges encountered and explain how these problems were addressed.

The group will describe how the product was reassembled by a detailed and organized table that describes specific tools usage, assembly difficulty, and pictures or videos where relevant. The outline created should be written with regards to an individual not familiar with the product, in which the individual can successfully reassemble the product.

This gate also demonstrated that the group can identify mechanisms their device uses to generate specific motion, control system behavior, modify/condition energy. They will identify its technical name, clearly state its purpose, document how the mechanism works, and provide equations that are required for the design of the mechanism.

Finally, the group will recommend at least three design changes for the product at the system level, including features that be would changed or eliminated; these changes should reflect global, societal, economic, or environmental concerns. Additionally, the changes should improve performance, serviceability, and cost, with regards to the fact that the products targets audience and price point.

Explore here ---> Gate Four