P16005: Motorized Standing Wheelchair 2
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Detailed Design

Table of Contents

Team Vision for Detailed Design Phase

Summarize:

Prototyping, Engineering Analysis, Simulation

New Pivot Point Prototyping

One of the problems with previous design of the standing wheelchair was having the pivot point of seat lower than knee level, which means the user has to slide back on the seat while the chair goes to standing position. Knees are pivot points of body while standing, and alignment of pivot point with knee makes the experience much easier as user does not need slide backward or forward on seat as it gets to standing position.
Pivot Point Prototype

Pivot Point Prototype

Drawings, Schematics, Flow Charts, Simulations

Full Model View

Links to 3D PDF's of our current model design is shown below. This includes the foot plate, actuator, lift system with parallel links, limit switch system, as well as the wheelchair base, seat, seat back, and other components. Allow Adobe Reader to be used as a plug-in on the edge site for the 3D PDF to work properly.

Overall Assembly

Seated Model

Standing Model

Below Are Pictures of the Full Model Assembly of the chair in the standing position.

Full Assembly

Full Assembly

Full Assembly

Full Assembly

To view a video of of the standing/seated motion of the wheelchair, click on the following link Lift Video

Chair Recline

In order to be able to use the Hoyer lift more easily, the seat back needs to recline to an angle of 25 degrees. The images below show the starting and ending point of this recline action. A double point remote release latch will be attached to the seat back. When activated, the pins will release and the back will be able to recline.
Seat Back Tilt Simulation

Seat Back Tilt Simulation

Limit Switch

One of the customer requirements is for the chair to have a maximum lift angle that can be easily set by the PTs. The current plan to accomplish this is through the assembly seen below. The end of the rod is fixed to the parallel links under the chair and the large bracket is fixed to the chair seat. As the seat lifts up the distance between them changes forcing a push button nut to move closer to a micro switch that will stop the chair when pressed.
Limit Switch Assembly Rear

Limit Switch Assembly Rear

Limit Switch Assembly Front

Limit Switch Assembly Front

Tray Research

Another customer requirement was for there to be a tray that could be easily attached and removed. Research is still being done on specific details, but it is very likely that the tray will be bought and then components will be designed and manufactured that will allow the tray to be attached and perform the functions it needs to. A nearly ideal example of a tray that can be purchased is seen below.
Potential Tray

Potential Tray

Lever Arm Cover

One issue that comes up by changing the pivot point is the position of new lever arm; the lever arm has to be located in front of current position and be placed between knees of client. In order to reduce the risk of injury we designed a cover for the new lever arm that is connected to calf pad and in result of that does not move with the lever arm. The cover will have padding material around it.
Lever Arm Cover

Lever Arm Cover

Pommel Options

2 of different options for pommel. Choice should be done by therapists.
Pommel Options

Pommel Options

Chest Restrain Options

4 of different options for chest restrain. Choice should be done by therapists.
Chest Restrain Options

Chest Restrain Options

Bill of Material (BOM)

Lever Arm BOM

The image below shows the BOM for the Lever Arm Assembly. Fabrication cost is still unknown so prices are estimations.
Lever Arm BOM

Lever Arm BOM

Lift BOM

The image below shows the BOM for the lift subsystem assembly. This BOM include the seat back tilting mechanism as well.
Lift Subsystem BOM

Lift Subsystem BOM

Electronics BOM

The image below shows the BOM for the electronics systems. This includes all the switches and control boxes.
Electronics BOM

Electronics BOM

Limit Switch BOM

The image below shows the BOM for the electronics systems. This includes basic bought components and approximate material requirements.
Limit Switch BOM

Limit Switch BOM

Calf Pad BOM

The image below shows the BOM for the calf padding assembly.

Calf Padding BOM

Calf Padding BOM

Floorplate BOM

The image below shows the BOM for the Floorplate. Prices are based on material costs from McMaster Carr.

Floorplate BOM

Floorplate BOM

Total Cost

The total estimated cost is $620 not including the pommel or chest restraint.

Test Plans

To see the most up to date version of the Test Plan, click the following link: Test Plan 12/08/15

Risk Assessment

To view the updated risk assessment from the Preliminary Detailed Design Review, click on the following link:
Risk Assessment

Risk Assessment

Design Review Materials

Plans for next phase

MSD II Schedule

MSD II Schedule


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