P14006 Bath Tub Lift Phase II Reviewedge.rit.edu/content/P14006/public/MSD14006 Phase III Review.pdf · Company Bathmaster Sonaris Bellavita Orca Portable Water Power P14006 Type

P14006 Bath Tub Lift Phase III Review Amos Baptiste Jeremy Czeczulin Andrew Hughes Richard Prilenski

Introductions

Name Major/Role

Amos Baptiste Industrial & Systems Engineer/Team Leader

Jeremy Czeczulin Mechanical Engineer

Andrew Hughes Mechanical Engineer

Richard Prilenski Mechanical Engineer

Agenda

• Phase II Overview

• Problem Definition

• Customer & Engineering Requirements

• Action Items

• Benchmarking

• Concept Selection

• Design Schematics

• Electrical & Mechanical Architecture

• Von Mises Stress Analysis, Displacement, and Factor of Safety

• Ergonomics

• Bill of Materials

• Project Plan (Week 9-12)

• Team Assessment

Problem Statement

• Bathtub lift – a device that provides assistance to an individual with physical disabilities, including limited balance, coordination, or mobility

• Can reduce the difficulties of raising and/or lowering an individual into the tub by utilizing a powered seat and a simple control module

• As population grows the number of aged individuals will greatly increase making demand for assist devices increase

• Project motivation – Theresa Loce

• Improve the current design

• Current device does not meet her needs

• Powered lift that is sturdy, comfortable, easy to use/clean, makes minimal noise, and takes into account physical limitations of user

• Ultimate goal – user maintains autonomy and privacy

Deliverables

• Effectively assist the user for bathing purposes

• Device is easy to access from starting position

• Minimized operating time

• Provide a comfortable and supportive seating area

• Accessible to 10th-70th percentile for both genders, regardless of age

• Reasonably lightweight and portable, able to be transported

Current and Desired State

Current

• Unstable

• Out of production

• Damaged

• Difficult access

• Obstructions prevent full use

Desired

• Easy use

• Easy access

• Portable

• Lightweight

Stakeholder(s)

• Primary Customer: Theresa Loce

• Contact: 585-647-2329

• Secondary Customer (s): Wheel chair users/handicap public & Elizabeth DeBartalo, Hospitals (RGH), Nursing Homes, suppliers/vendors, & individuals recovering from knee surgeries.

• Contact: [email protected]

• Faculty Guide: Art North

• Contact: [email protected]

• Sponsor (financial support): RIT & Theresa Loce

mailto:[email protected]

mailto:[email protected]

Benchmarking

Company Bathmaster Sonaris Bellavita Orca Portable Water Power P14006

Type Battery Battery Battery Hydraulic Battery

Number of Lifts 8 to 10 N/A 12 Infinite 12-Oct

Time to charge 3 hours N/A 6 hours 0 hours <= 4 hours

Weight Capacity 308 lbs 300 lbs 400 lbs 200 lbs >=150

Weight of device 15.75 lbs 20.5 lbs 35 lbs 19 lbs 20-30 lbs

Arm rest No No No Yes Yes

Portable Yes Yes Yes Yes Yes

Recline angle 40 degrees 50 degrees 0 degrees 0 degrees 40-90 degrees

Rotate angle 0 degrees 0 degrees 0 degrees 360 degrees >=180 degrees

Lifting Height 3"-18" 2.3"-18.8" 17" 2"-21" TBD

Back rest dimensions 24" x 14" 25.1" H x12.5"-14.1"W 26" x 27" 15" x 15" TBD

Seat dimensions 20" x 15"; 27" with flaps 22.4"L x 12.7"W;27.5" with flaps 14.75"W x 19"D N/A TBD

>= 18”

25” x 15” 17” x 15”

10-12

Action Items from Wk 6-9

ID Action Items Owner Status Notes

1

Create drawing from 3D models of bathroom and devices having multiple

designs Andrew H. Completed

2 Use ANSYS or other finite element analysis program to test 3D models Andrew H. Completed Was completed in Inventor instead of ANSYS

3 Create ergonomics drawings based on engineering/customer requirements Amos B. Completed Met with Dr. Marshall for review

4 Create a budget and propose it to Art based on bill of materials Amos B. Completed

5 Refine functional decomposition Team Completed Highlighted the function to focus on

6 Plan or conduct a design of experiment for the bath tub lift Amos B. In progress Consider purchasing actuator

7 Create a Bill of Materials Richard P. Completed Rough draft and may be changed overtime

8 Conduct stress analysis on CAD drawings Richard P. Completed

9 Calculate the power necessary to power Jeremy C. Completed Met with Dr. West for review and EE's

10 Update and narrow down concept drawings of project (hand-drawn) Jeremy C. Completed

11

Specify the requirements of parts of the device (battery voltage, steel rating,

etc.) Jeremy C. Completed Met with Dr. Boedo

12 Relearn the basics of Creo Parametric; if needed, learn Autodesk Inventor Jeremy C. In progress May not be needed with the usage of Inventor

13 Make any necessary changes to existing documents or pages Team In progress Need to update documents on Edge

Electrical vs Hydraulic Design

• Pro’s

• Easier use (automated)

• More use scenarios

• Con’s

• More complicated design

• Technical limitations

• Pro’s

• Simpler design

• Potentially lighter

• Con’s

• Dependent on water source

• Limit to power ability

• Requires more work from user

In the end, the battery design fulfills requirements in a more efficient manner

Updated Customer Requirements

Updated Engineering Requirements

Updated Engineering Matrix

System Functional Decomposition

Initial Single Pillar Design

Single Pillar Design

Scissor Lift Design

Full Battery Design for Both Cases

1 Raise Device Water Power Battery Power Inflation Power Remote ControlMagnetic

RepulsionChair Crane

2 Transfer Device

Getting items for

support (trapeze

handle)

Use of crutchesAutomation to lift

user to the device

Personal

assistant to help

user to device

Incorporate

user's assist

device

3 Assist Legs

Personal

Assistant to help

legs be secured

Water power

Battery power

(platform slides

out)

Remote controlReclining

Platform

4Rotate/Slide

DeviceManually Water power Battery power

Personal

assistantSpring loaded Remote Control

5 Lower Device Water Power Battery PowerInflation Under

chairRemote Control

Magnetic

RepulsionChair Crane

6Turn on Water to

fill tub

Manually turn

knob

Personal

AssistantRemote Control Relocate knobs

5 61 2 3 4Sub function

Solutions

Concept Selection

Criteria

Scissor Design Pillar Design

1 Raise Device + -

2 Transfer Device S S

3 Assist Legs S S

4 Rotate/Slide Device S S

5 Lower Device + -

6 Turn on Water to Fill Tub S S

7 Affordable - +

8 Fits Time Constraints + -

9 Safety + -

10 Light Weight - +

11 Portable + -

12 Durability + -

+ 6 2

- 2 6

Pro’s & Con’s of the Lift Designs

Pillar Lift

• Pro’s • Lightweight

• Simpler design

• Con’s • Some features may be

manually operated

• Weaker mechanically

• More prone to tipping

• Lift motor/mechanisms weaker

• Limited mobility and range of motion

Scissor Lift

• Pro’s • Stronger mechanics

• Able to lift more

• More automation possible

• More Stable

• Con’s • Larger -> heavier

• More costly

• Greater risk of electrical injury

Ultimately, the scissor lift is able to better satisfy project needs

Pillar Lift CAD Design

Scissor Lift CAD Design

*

https://www.youtube.com/watch?v=09VFLwI7avQ

Bathroom

Electrical Architecture

AC/DC Converter Battery 12/24 V Acutator Moving Parts

Controller

220V60 A

Mechanical Architecture

Power Calculations

Extending Arm Calculations

• Stress

• 10.46 ksi

• Deflection

• 0.0937 in

Scissor Lift Calculations

• Stress

• 3.92 ksi

• Deflection

• 0.0031 in

Pillar Lift Calculations

• Stress

• 1.49 ksi

• Deflection

• 0.4675 in

Stress Analysis for Scissor Lift

Figure (1) – Von Mises Stress Note: ksi value was limited to 6 ksi to show stress colors in support area. Max stress value marked was 4.8 ksi.

Scissor Lift Displacement

Figure (2) - Displacement Note: Figure 2 shows the maximum displacement in inches of the support frame. Max value marked was 0.03262 in.

Scissor Lift Modified Disp.

Figure (3) – Displacement Limit Figure 3 shows a limit on displacement to farther show the dispersion of displacement on the scissor frame. Max value was 0.007 in.

Stress Analysis for Extending Arm

Figure (4) – Von Mises Stress Analysis It is noted that the stress range in the vertical pillar area ranges from 2-10.5 ksi. The acceptable stress value for stainless steel is 30-36 ksi.

Extending Arm Displacement

Figure (5) – Displacement As suspected, the largest displacement values are shown at the edge of the horizontal pillar. The value was measured to be 0.1254 in.

Extending Arm F.O.S.

Figure (6) – Factor of Safety In the medical field, most companies try to aim for a F.O.S. range of 2-4. From that assumption, we will follow that guideline when it comes to the stress analysis of our frame for the bathtub lift. The noted F.O.S. range on the vertical pillar was from 3-7.

Ergonomics Important factors to consider: • Intended users can fit

the device • Lumbar support • Arm rest height and

length • Leg clearance

** All measurements are based on ANSUR Database

Bill of Materials Material Name Weight (per cc^3) Elastic Modulus(ksi) Tensile Strength (Psi) Shear Strength (psi) Corrosive?

1 Fiberglass 2.49 20500 No

2 Gel coated Fiber Glass 2.49 20500 No

3 Acryllic 1.2 5420-10700 No

4

5

Material Name Weight (per cc^3) Elastic Modulus(ksi) Tensile Strength (Psi) Shear Strength (psi) Corrosive?

1 Carbon fiber 1.6 15954 No

2 Aluminum 2.69 40000 No

3

4

5


1 Fiberglass 2.49 20500 No

2 Carbon Fiber 1.6 15954 No

3 4140 Carbon Alloy Steel (Annealed) 7.85 60200 No

4 Polyurethane Alloy 0.970-1.40 1740-9720 4930-7690

5


1 A36 Steel 7.85 36300 Yes


3 Stainless Steel 0.19-9.01 11200-46000 6150-348000 No

4

5


1 Gel Coated Fiber Glass 2.49 20500 No

2

3

4

5


1 A36 Steel 7.85 36300 Yes


3 Stainless Steel 0.19-9.01 11200-46000 6150-348000 No

4

5

Extendable Arm

Chair (Seating Material)

Chair (Frame)

Base (excluding steel fixture for extendable pillar and sunction cups)

Extendable Pillar (Raises/Lowers Chair)

Arm Rest

Bill of Materials

Material Cost

Stainless Steel (Beam) 60.00$

Stainless Steel (Outside Channel) 100.00$

Battery with Charger 250.00$

Stainless Steel (for legs/lift) 51.00$

Suction Cups (4x) 100.00$

Aluminum Pipe 80.00$

Gel Coated Fiber Glass

Gel Coat 70.00$

Fiber Glass 26.00$

Mold 200.00$

Control Module & Electrical Wiring 250.00$

Actuator 350.00$

Total 1,537.00$

Total with 30% increase 1,998.10$

Power Sources – Electrical Actuator vs. Servo Motor • Upon review, the electric actuator would be a perfect fit in

assisting with the raising and lowering of the chair frame.

• Several companies were contacted for more advanced specs of the actuators and the main issue was that they are not waterproof.

• Therefore 2 scenarios rise up, the first is to do further research on alternative methods and the second is to design a waterproof housing for the actuator (that would take up a significant amount of time).

Risk Assessment Risk Item Cause Effect Likelihood Severity Importance Actions to Minimize Owner

1User injury due to

falling/slipping off device

No adding arm rails.

Combination of

material, water and

human skin not

having enough

friction causing user

to slip.

Minor to severe injury to the

customer/user1 3 3

Implement a safety

device and use high

friction materials

Team

2 ElectrocutionExposed electrical

components

User may be electrocuted by

direct contact with device or

through water

1 3 3

Design electrical

components to be

isolated/sealed

from rest of device

Team

3Electric power supply

inconsistent

Charge from battery

may not be

sufficient to operate

device when running

low

User may experience longer

operation times or may

become trapped in tub

2 3 6

Apply a warning

system/visual

indicator that the

battery is low.

Team

4 Device weight capacity

Device not able to

lift well over the

minimum

requirement

Device fails under heavy

loading, trapping and possibly

injuring user

1 3 3

Through testing

device must lift

>150 lbs

Team

5

Not being able to fulfill

requirements of broad user

base (height/weight

differences)

Not conducting an

ergonomics study on

the stature of the

users percentile and

their reach

User may be too big or too

small for device. User may get

injured due to lack of space or

not being able to reach certain

items. Customer dissatisfaction

2 2 4

Conducting

ergonomic

experiments on the

target percentile

range

Amos

6 Fixture dimensions

Measurement errors

of the bath tub and

the device. Not

considering

thickness of

materials in specs.

Device not able to fit in the

tub. Customer not being able

to use the device.

2 3 6

Have multiple team

members measure

the dimension of

the tub and for

every step of the

process, re-measure

to verify meeting

constraints

Team

7 Safety of user’s legs

When fixture is

lowering it does not

allow enough room

for legs

Minor to sever injury to the

customer/users legs 1 3 3

Apply a foot rest at

the base of the

device so the user

can place their feet

before operating

Team

8Transfer from starting position

to the device

Unsafe transition

from starting

position to the

device

Possible falling injury 1 3 3

Option1: Having the

device being able to

slide out the tub for

the user to access.

Option 2: Ensure

that the device can

rotate out of the

tub and is stable for

users that can stand

to use as a support.

Team

9Not being able to meet

deadlines/milestones

Not having a well

developed project

plan and keeping it

updated

Product delay which may lost

customers trust 2 2 4

Have daily or

weekly updates on

assignments and if

help is needed Team

10 Going over budget

Not keeping track of

budget or knowing

what the budget is

Having to ask for more or

falling short on supplies to

develop the product.

1 1 1Schedule to audit

budget every 2

weeks. Team

11All team members not being

able to meet

Miscommunication

or lack of

communication

between team

members

Team members missing

meetings or not being active in

their roles

2 1 2

Communicate with

team verbal and

text/email when

and where will

meetings will take

place. Amos

12User hand getting injured in

the process of using the seat

Exposed folding

mechanism and/or

seat lowering to

quickly

Hand chopped off 2 3 3

Ensure through the

proof of concept

the device will not

lower quickly or

collapse. In

addition, make a

safe folding

mechanism. Team

Risk Assessment

Risk Item Cause Effect Likelihood Severity Importance Actions to Minimize Owner

1User injury due to



Combination of

material, water and

human skin not

having enough


to slip.


customer/user1 3 3

Implement a safety

device and use high

friction materials

Team


components



through water

1 3 3

Design electrical

components to be

isolated/sealed

from rest of device

Team


inconsistent

Charge from battery

may not be


device when running

low




2 3 6

Apply a warning

system/visual

indicator that the

battery is low.

Team


Device not able to

lift well over the

minimum

requirement



injuring user

1 3 3

Through testing

device must lift

>150 lbs

Team

5



base (height/weight

differences)

Not conducting an

ergonomics study on

the stature of the


their reach






2 2 4

Conducting

ergonomic

experiments on the

target percentile

range

Amos


Measurement errors

of the bath tub and

the device. Not

considering

thickness of

materials in specs.



to use the device.

2 3 6

Have multiple team

members measure

the dimension of

the tub and for

every step of the

process, re-measure

to verify meeting

constraints

Team


When fixture is


allow enough room

for legs




the base of the

device so the user


before operating

Team


to the device

Unsafe transition

from starting

position to the

device


Option1: Having the



the user to access.

Option 2: Ensure

that the device can

rotate out of the




Team



Not having a well

developed project

plan and keeping it

updated



Have daily or

weekly updates on

assignments and if

help is needed Team



budget or knowing

what the budget is





budget every 2

weeks. Team


able to meet

Miscommunication

or lack of

communication

between team

members



their roles

2 1 2

Communicate with

team verbal and

text/email when

and where will

meetings will take

place. Amos



Exposed folding

mechanism and/or

seat lowering to

quickly


Ensure through the

proof of concept

the device will not

lower quickly or

collapse. In

addition, make a

safe folding

mechanism. Team

Risk Assessment

Risk Item Cause Effect Likelihood Severity Importance Actions to Minimize Owner

1User injury due to



Combination of

material, water and

human skin not

having enough


to slip.


customer/user1 3 3

Implement a safety

device and use high

friction materials

Team


components



through water

1 3 3

Design electrical

components to be

isolated/sealed

from rest of device

Team


inconsistent

Charge from battery

may not be


device when running

low




2 3 6

Apply a warning

system/visual

indicator that the

battery is low.

Team


Device not able to

lift well over the

minimum

requirement



injuring user

1 3 3

Through testing

device must lift

>150 lbs

Team

5



base (height/weight

differences)

Not conducting an

ergonomics study on

the stature of the


their reach






2 2 4

Conducting

ergonomic

experiments on the

target percentile

range

Amos


Measurement errors

of the bath tub and

the device. Not

considering

thickness of

materials in specs.



to use the device.

2 3 6

Have multiple team

members measure

the dimension of

the tub and for

every step of the

process, re-measure

to verify meeting

constraints

Team


When fixture is


allow enough room

for legs




the base of the

device so the user


before operating

Team


to the device

Unsafe transition

from starting

position to the

device


Option1: Having the



the user to access.

Option 2: Ensure

that the device can

rotate out of the




Team



Not having a well

developed project

plan and keeping it

updated



Have daily or

weekly updates on

assignments and if

help is needed Team



budget or knowing

what the budget is





budget every 2

weeks. Team


able to meet

Miscommunication

or lack of

communication

between team

members



their roles

2 1 2

Communicate with

team verbal and

text/email when

and where will

meetings will take

place. Amos



Exposed folding

mechanism and/or

seat lowering to

quickly


Ensure through the

proof of concept

the device will not

lower quickly or

collapse. In

addition, make a

safe folding

mechanism. Team

6

Test Plan

• Team plans on purchasing a small actuator and rechargeable power source

• Actuator ~ $20-30

• Battery ~ $10

• Create a scaled test rig to test design feasibility

• Conduct worst-case scenario simulations

Team’s Vision

Project Plan for WK 10-12 ID Action Items Owner

1

Incorporate Ergonomics drawings with CAD

designs Amos, Jeremy, & Andrew

2Refine CAD designs

Andrew

3Design of control module

Andrew & Jeremy

4Develop a battery charging system

Jeremy & Richard

5Contact and meet with Theresa

Team

6Establish proof of concept in all critical areas

Team

7Develop a test plan for the device

Richard

8Refine Bill of Materials

Richard & Amos

9

Arrange meetings with faculty to review Detailed

Design for all critical areas Team

10Purchase actuator

Team

Project Plan for WK 10-12

Questions?

Documents

P14006 Bath Tub Lift Phase II Reviewedge.rit.edu/content/P14006/public/MSD14006 Phase III Review.pdf · Company Bathmaster Sonaris Bellavita Orca Portable Water Power P14006 Type