156B Week 4
Overview of Status of Analysis, Design, Fabrication, Tests, etc.
Armrest assembly (A0008) created using COTS parts
Presented design to engineering staff for feedback
CAD spreadsheet updated for new armrest design and complete assembly
Accomplishments from Previous Week
COTS armrest modeled
Presented design to sponsors for approval
Presented design to engineering staff for feedback
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Update designs with considerations raised from meetings
Begin purchasing parts
Complete Proof of Concept presentation
Complete Report Draft 1
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
4/22:
Concerns about pinching/sharp corners in design -> rubber covers for side/ends of 8020, 3D printed bumpers, foam covers
Possibly altering current footrest design to have stacking sections
Making desk large enough so left arm could also fit on it
*See "4/22/2020 Delson/Sponsor Meeting"*
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
4/22 (Delson):
Concerns about pinching/wobbling in armrest design
Double check with sponsors that right arm is standard for measurement -> sponsor suggested including option of using left arm
Begin purchasing base and other parts
Discuss CAD with engineering staff for feedback -> meetings held with Tom, Ian, and Steve
Updated BOM
Consider how easy adjustment is
Roxanne can order parts and ship to team
*See "4/22/2020 Delson/Sponsor Meeting"*
4/24 (Steve):
Include color in CAD
Make 8020 armrest mounting smaller or replace with another component (more complexity than needed)
Possibly replace travel stops on armrest with bolts (components not protruding to injure child)
Change hinge/locking mechanism to lock it in the positions (prevent slamming down)
Be aware of twisting/wobbling due to applied torque on the backrest
possibly replace rod-ends with 1 DOF
Add frame to back of chair to close off the open frame (helps with twisting issue)
Ratchet mechanism can slip and cause injury
mechanism has three functions instead of one, and if it fails, all those functions do too)
Large dog bone to adjust in center for 4 bar linkage
Washers between rod end and channel
Ease/time for adjustment
design for operator, keep controls far away from patient
Look at existing footrests for inspiration
Don't worry about cost too much due to product being for medical facility
has to be robust and functional
Armrest could be a piston mechanism
existing design is a two handed operation
*See "Engineering Staff CAD Overview 4/24 and 4/26"*
4/26 (Tom/Ian):
Possibly add second ratchet and pawl or friction knob to backrest assembly to prevent back from falling all the way forward
Comfort for nurses is as important as for the patient
Swivel chair to move away from the footrest
Add handrail to left side to help patient get in/out of chair
Concerns about swiveling of chair for safety
Back adjustment may be a little overkill
linear slider issues
pantograph mechanism
Update CAD to include brackets/braces and 8020 covers
Fabrication of footrest
make out of plywood, buy saw
Tom can possibly make footrest
pyramid steps
Start ordering parts and finalize CAD ASAP
Bigger consideration for child safety in design
*See "Engineering Staff CAD Overview 4/24 and 4/26"*
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
none
Risks and Areas of Concern
safety
CAD of office chair components
manufacturing
Resources or Information Required but not Available
CAD/dimensions of office chair components
Schedule
Finalize CAD/drawings and order parts
Update Gantt chart.
Budget (list amount spent and amount remaining)
none spent
Progress on Report and Webpage
Proof of Concept presentation started
Report Draft 1 started
Webpage updated
Documents: