OverviewConcept DesignsPrototypeFinal Drawings

The Olin Sweet Hitch Team originally tried to reinvent the Adiabatic Demagnetization Refrigerator’s heat switch, but concluded the summer program by innovating it. We learned the most about cryogenics, the ADR, and thermal conduction while trying to reinvent the part, but for many reasons we ended almost where we began and gained experience trying to make one on our own. The reasons for this change were a function of what we learned and will be explored in this section, along with the final design and ideas that almost made it along the way.

Two goals stood out at the beginning of the project: to eliminate a characteristic ‘jamming’ present in the first heat switch, and to possibly increase the thermal conductivity of the switch. We understood that the jamming was inconvenient, and that the switch itself was a bottleneck in the ADR, dependant on the speed of heat flow. An idea that stuck early was to possibly include a type of contact ‘scrubbing,’ where the surface that transmitted heat from the tongue would scrape as it pressed against it so that a more intimate contact could be established. With this early suggestion from Simon Bandler along with backing from Gill Pratt, we began brainstorming right away – keeping this in mind. We pumped out almost fifty ideas and narrowed them down to three designs that seemed worth pursuing in a span of two weeks. These ‘final’ three underwent many expanding revisions, which led to multiple versions of each idea. These versions eventually combined to give us what we thought were our three best options: the WIDGET, Flexure, and Toggle Vise Grips. While it would slightly complicate the design, all of these were fully capable of providing a scrubbing contact that would ‘renew’ itself with every use. Each design had its advantages and pitfalls, and while they were hard to chart, were still very tangible.