156B Week 1

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

• • Testing porototype by placing weights on it to determine force needed to achieve desire flow rate

  • Discussing an additional component with sponsor to make our device more diverse

  • Analyzing individual components to see what can be purchased and what will have to be built

Accomplishments from Previous Week

• • Presented risk reduction achievements to professor, classmates and sponsor

Goals for Next Week (list names after each item). Use specific and measurable objectives.

• Start work on 4-bar linkage prototype (Team)

• Determine the approximate spring torque values for springs used in 4-bar prototype (Cj,Justin)

• Contact a representative from www.centurysprings.com to see  if there is a spring that meets our needs or if we will have to order a custom set. Also lead time is a concern.(Justin)

• Meet with sponsor to learn about a few more secondary objectives (Team)

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

• • Notes from in person meeting with Dr. Mazzei on March 15th:

    • Look into placing springs in series or torsion bars on the device to apply the pressure we need

    • Liked the idea of modeling the safety mechanism after a lock used to keep a ladder open

    • Suggested we consider designing the release of the safety mechanism to be accessed by the operators thumb

    • Warned us about making sure our designs do not clamp the tubes at the bottom of the IV bag.

  • Note from email from Dr. Mazzei on April 2nd:

    • Consider developing a way to use the bag with cell saver IV bags (IV bags that recycle blood for a patient but have air in them)

Instructor Comments from Last Meeting and Actions Taken to Address these Comments  (indicate date of comments and if via email or in person)

• • Notes from in person meeting with Dr. Delson on March 15th:

    •  Recommended that we be very careful with verfiying all information will Dr. Mazzei 

    • Would like us to make sure that our knowledge of the medical aspects of the project are correct

    • Discussed with us the spring we most likely need for our project will be one with a high pre-load and low stiffness

    • Recommend we look at the springs that allow tape measures to be pulled back into their casing

    • Suggested we place rubber bands on our prototype to test flow rates

  • Notes from risk reduction presentation on March 20th:

    • Suggested that we consider the idea our classmate had to use pure weight to apply the force and asked us to determine how much weight would be needed

    • Told us to vary parameters more systematically in risk reduction tests in terms of the preload and stiffness that we are testing

  • Actions taken to address comments:

    • Tested prototype with rubber bands to visualize how prototype will respond when pressure is applied

    • Tested prototype with weights on it to find force needed to get desired flow rate

Comments from Other Students in the Class (indicate date of comments and if via email or in person)

• • All comments from our classmates are from the risk reduction presentation on March 20th.

  • About the presentation: 

    • More pictures on the slides

    • Speak at a louder volume 

  • About the project:

    • Many of the suggestions used electronical means to solve our problems which we are trying to avoid at the request of our sponsor

    • Apply pressure at three different points in the bag so that the application of pressure can be adjusted based on how much fluid is left in the bag.

    • Look into gas springs.

    • If we want to use a ladder lock idea for the safety mechanism, we should consider having it lock gradually based on how far the device is opened.

    • Experiment with fluid going into something similar to veins so that we can make sure that our pressure is accurate.

    • Place edges on three of the sides of the device to prevent the bag from sticking out of the sides. 

Risks and Areas of Concern

• Areas of Concern:

  • How can we provide leverage for the 4-bar linkage system when springs are at max torque

  • What will the lead time be for parts ordered?

  • Can we buy any parts directly from a local vendor?

    • What is the best way to test our prototypes and different methods of applying pressure to the system?

    • How will the addition of a sensing component affect the portability, cost and pressure application of our product?

  • Risks:

    • Safety mechanism

Resources or Information Required but not Available

• • Need more information from our sponsor about the additional component he would like us to consider 

Schedule

• • Begin work on additional prototypes - Week 2

  • Begin preparations for presentation - Week 2

  • Complete two additional prototypes - Week 3

  • Presentation - Week 3

  • Test prototypes with motors and springs - Week 4

Budget (list amount spent and amount remaining)

• • Spent: $0

  • Remaining: $1500

Progress on Report and Webpage

• • At this point, we have not begun the report.

  • We are beginning to work on the front page and coordinating the internal pages.