P19093: Over-Bed Hospital Table

Preliminary Detailed Design

Table of Contents

1 Feasibility Analysis
2 Drawings, Schematics, Flow Charts, Simulations
3 Bill of Material (BOM)
4 Test Plans
5 Design and Flowcharts
6 Risk Assessment
7 Design Review Materials
8 Plans for next phase

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Plan for Preliminary Detailed Design Phase:

During the Preliminary Detailed Design Phase our team plans to start creating a testing prototype of our device based on our concept selections. We will develop a test plan to help us measure different functions and capabilities of the prototype. We also plan on taking a tour of Unity Hospital and setting up a meeting with the ID team to review current progress and updates on engineering requirements.

What was Actually Accomplished:

We were able to tour Unity Hospital and meet with the ID team to discuss designing and our concept selection. During this phase, we successfully created our first testing prototype of the base of the hospital bedside table. We created a test plan to test maneuverability, completed calculations to determine center of gravity and maximum/minimum weight the tabletop can withstand under different conditions, and a first revision of a Computer-Aided Design model and drawing of the hospital bedside table. Specific types of casters were chosen to be potentially used on the final prototype.

Feasibility Analysis

Complete Feasibility Analysis can be found [here]

Drawings, Schematics, Flow Charts, Simulations

3D models of potential base designs were made using Computer-Aided Design software.

Base Design 1: Potential Base 1

Potential Base Design 1

Base Design 2: Potential Base 2

Potential Base Design 2

Bill of Material (BOM)

Aluminum Extrusion

80/20 Stock Used for Prototype Testing

We used these to help build a prototype for our simulation testing. The aluminum extrusion was retrieved from excess aluminum stock in the Industrial & Systems Engineering Department.

Connectors

90 degrees Aluminum Connector

Aluminum Plate Connector

These were used to connect the aluminum stock to help build a base. The connectors were retrieved from the Mechanical Engineering Department.

Casters

Casters Used for Prototype Testing

Brand: Everbilt
Size: 2" (from mount to bottom of wheel)
Cost: $4.37
From: Home Depot Details:

Non-Marking Rubber
Holds up to chemicals and solvent exposure
Great for use in institutional spaces like hospitals and labs

Threaded-Stem Leveling Casters

Caster #1 Considering for Final Prototype

Brand: McMaster-Carr
Size: 2.8" (from mount to bottom of wheel)
Cost: $23.23
From: McMaster-Carr Details:

Thumbwheel Adjustment
Can compensate for uneven floors
Durable nylon wheels, impact and wear resistant
Shielded bearings resist dust and debris

Cardinal Casters with Polyurethane Wheels

Caster #2 Considering for Final Prototype

Brand: McMaster-Carr
Size: 4.25" (from mount to bottom of wheel)
Cost: $17.25
From: McMaster-Carr Details:

Shield keeps out contaminants
Polypropylene core

Test Plans

Test Plans are used to visually see how a potential prototype would work. Test Plan 1's purpose is to test how easily the base would move using the defined engineering requirements.

Test Plan 1: Ease of Maneuverability

Objective: To test a base configuration with different casters and loads to further our understanding of a final base design.

Needed:

Base constructed out of 80/20 aluminum bar stock
Casters
Weights

Experiment setup: Each team member will partake in this experiment. Each member will push the base 3 different distances with 3 different loads (loads and distances will be the same each time). This experiment can be repeated each time there is a variation in the design (different base, different casters, different floor). Each trial will be timed and feedback will be taken from each team member on how it felt moving the base.

Results can be found [here]

Based on feedback during testing, the base was difficult to control during movement. Extra force was needed to keep the base moving straight in one direction. Solutions to correct this is to change 2 of the 5 casters from swivel-type to rigid-type.

(Note: Testing is not complete and will be continued in the Detailed Design Phase)

Design and Flowcharts

Requirement --> Component --> Solution for the different parts of the bedside table.

Updated Table Top Flow Chart

Updated Supporting Rod Flow Chart

Updated Base Flow Chart

Risk Assessment

No additional risks have been identified, but Risk 23's importance was increased from 20 to 28. The mitigation plan for this risk is complete MSD's purchasing process paperwork for several parts at once as early as possible.

Risk Assessment

Design Review Materials

Links

Dates for the next reviews

Preliminary Detailed Design Review - November 13th, 12-1pm (Rochester General Hospital)
Detailed Design Review - December 4th, 12-1pm (location TBD)