Team Vision for Detailed Design PhaseSummarize:
- Finalize Lift Subsystem Design
- Finalize Foot Plate Design
- Finalize lever arm location and protection
- Finalize Chair tilt design and mechanisms
- Complete Bill of Materials
- Create drawings for new parts
- Make a list of options for: pommel, hip pad, chest restraint, desk tray
- Create and send out an updated Expectations Letter
- Work on Test Plan
Prototyping, Engineering Analysis, Simulation
New Pivot Point PrototypingOne 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.
Drawings, Schematics, Flow Charts, Simulations
Full Model ViewLinks 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.
Below Are Pictures of the Full Model Assembly of the chair in the standing position.
To view a video of of the standing/seated motion of the wheelchair, click on the following link Lift Video
Chair ReclineIn 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.
Limit SwitchOne 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.
Tray ResearchAnother 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.
Lever Arm CoverOne 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.
Pommel Options2 of different options for pommel. Choice should be done by therapists.
Chest Restrain Options4 of different options for chest restrain. Choice should be done by therapists.
Bill of Material (BOM)
Lever Arm BOMThe image below shows the BOM for the Lever Arm Assembly. Fabrication cost is still unknown so prices are estimations.
Lift BOMThe image below shows the BOM for the lift subsystem assembly. This BOM include the seat back tilting mechanism as well.
Electronics BOMThe image below shows the BOM for the electronics systems. This includes all the switches and control boxes.
Limit Switch BOMThe image below shows the BOM for the electronics systems. This includes basic bought components and approximate material requirements.
Calf Pad BOM
The image below shows the BOM for the calf padding assembly.
The image below shows the BOM for the Floorplate. Prices are based on material costs from McMaster Carr.
Total CostThe total estimated cost is $620 not including the pommel or chest restraint.
Test PlansTo see the most up to date version of the Test Plan, click the following link: Test Plan 12/08/15
Risk AssessmentTo view the updated risk assessment from the Preliminary Detailed Design Review, click on the following link:
Design Review Materials
- Notes from review
- Action Items