Johnson, Peter Knox2010-03-292010-03-292009-12https://hdl.handle.net/11299/59877University of Minnesota M.S. thesis. December 2009. Major: Mechanical Engineering. Advisor: William Durfee. 1 computer file (PDF); iv, 49 pages, appendices A-D. Ill. (some col.)Pneumatic hand tools have been used for many decades. These tools help users accomplish tasks with much less effort than is required with manual tools. However, one significant drawback of pneumatic tools compared with manual hand tools is that the user is disconnected from the output forces the tool is creating. This has various safety and functionality issues. A pair of pneumatic powered loppers was developed to demonstrate the potential of force-multiplying, pneumatically powered hand tools with haptic control. A purely mechanical control system was tested and found to provide proportional feedback over the range of operating conditions. The work required to cut through different sizes of dowels and branches was also calculated and tested against the prototype to determine the amount of compressed air needed to operate the loppers. It was determined that the loppers could have an onboard, high pressure tank that could provide enough energy for average homeowner use. For commercial use a larger external tank would be required.en-USToolsPneumatic hand toolsSafetyForceMechanical EngineeringThesis or Dissertation