P17011: Wheelchair-Accessible Restroom
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Subsystem Build & Test

Table of Contents

Team Vision for Subsystem Level Build & Test Phase

The Goal for this phase was to complete the manufacture of subsystem level components prior to system integration.

Subsystem Build Summary

Mechanical Subsystem Build Summary

The breakdown of component manufacture was split approximately 50/50. 50% of the components were manufactured by Tom Skudlarek and the other 50% were completed by the staff of the Mechanical Engineering shop. The Components were predominantly made using the 3-Axis CNC Mills in the shop.

Machined Mechanical Components

Base Extender (Qty 2x)

Base Extender (Qty 2x)

Base Extender

Base Extender

Base Mount Plate (Qty 2x)

Base Mount Plate (Qty 2x)

Base Mount (Qty 2x)

Base Mount (Qty 2x)

Base Plate (Qty 1x)

Base Plate (Qty 1x)

Other than the surface finish on some of the components, the parts came out great. In order to save time in constructing and assembling the prototype, a finish pass was never run. A huge thanks goes out to the RIT Mechanical Engineering Machine Shop!

Composite Subsystem Build Summary

Laser Cut Template

Laser Cut Template

To build the toilet seat, the initial layers and foam core were cut to size using a laser cut template. The template was the exact size and dimensions of the desired seat. With all the shapes cut, the surface was prepped for layup.

Trimming The Foam Core

Trimming The Foam Core

Mixing The Epoxy

Mixing The Epoxy

  1. A coat of turtle wax was applied to the surface
  2. After allowing several minutes for the wax to harden and turn to a haze, it was removed with blue shop towels
  3. Steps 1 and 2 were repeated.
  4. The proper amounts of epoxy we mixed and painted onto the first layer of tooling fabric
  5. The wetted fabric was draped over the layup surface and allowed to set (stiffen slightly) prior to the additional layers.
  6. Following the original design of the seat, additional layers were added with the same process as in step 5.
  7. All layers were liberally coated with epoxy prior to layup
  8. The seat was then left to cure for over three days before any attempt was made to remove the seat from the polycarbonate

Test Results Summary

The original seat testing procedure as follows:

Seat Testing Procedure:
  1. Place Toilet Seat on edge of table to simulate being cantilevered on toilet base sub assembly.
  2. Using C-Clamps and Carpenter's clamps, apply significant force to the seat to simulate being bolted to the toilet base sub assembly.
  3. Photograph seat pre-testing
  4. Apply a proof load of 50% the ultimate load of 500 [lb] to the seat.
  5. Remove load and inspect seat for signs of stress and yielding. Photograph and compare to pre-testing photograph data.

Component Test Set Up

Toilet Seat Test Set Up

Toilet Seat Test Set Up

Toilet Seat Test Set Up

Toilet Seat Test Set Up

Toilet Seat Test Set Up

Toilet Seat Test Set Up

Toilet Seat Test Set Up

Toilet Seat Test Set Up

As the above photos show, the test conditions almost mirrored the design for the cantilevered toilet seat. The seat was located on the edge of the table on the exact edge that it will sit on the base plate of the toilet seat mount. From here 1-C-clamp and 3-Carpenter's Clamps were used to fix the seat to the table.

Component Testing

As was stated in the original test plans, the seat was incrementally loaded. First, the seat was pushed on using Tom's hands to test the set ups "sturdiness". From here, one hundred pounds of mass were added to the seat which were provided by Cassandra Derr. This weight simulates 50% of the proof load of 200 pounds.
Seat Under 100 [lb] (Cassandra Derr) Load

Seat Under 100 [lb] (Cassandra Derr) Load

From here the seat was taken to its proof load of just over 200 pounds.

Seat Under 200 [lb] Proof Load

Seat Under 200 [lb] Proof Load

Post Testing the seat was inspected for damage or signs of stress. If the fibers had been stressed beyond its yield point, in theory, they would show signs of discoloration.

Seat Post Load Testing

Seat Post Load Testing

Risk and Problem Tracking

Luckily, the aforementioned risks from the build and test prep page have been resolved. The turtle wax was applied in multiple coats to the polycarbonate, which, after the seat cured, allowed the seat to pop right off. The seat was also able to survive testing after very cautious load application.

The new risk to be added is that the bolt holes being hand drilled into the composite seat won't align with the machined holes in the base plate.

Plans for next phase

Next Phase, the desired goal is to have a fully assembled seat and lifting mechanism.

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