TECHNICAL MANUAL FOR
MEGAN DOWNEY’S
STANDING WHEELCHAIR
Made by Rochester Institute of Technology Senior
Design Team P15005
Disclaimer
This manual is intended to be a quick guide for any possible questions that may come up when attempting
to use, fix, or modify the wheelchair. Due to the nature of the RIT senior design program, all students who
worked on this project graduated May 2015 and will not be the point of contact. If any issues arise, please
contact the Senior Design Staff at eademe@rit.edu or 585-475-2152 RIT nor the Engineers are responsible
for any damage or injury caused by the use of this wheelchair.
TABLE OF CONTENTS
Genreal Information ..................................................................................................................................... 1
How to operate ......................................................................................................................................... 1
Powering the Chair-drive mode ............................................................................................................ 1
Powering the Chair- Lift Mode .............................................................................................................. 2
Positioning Supports ............................................................................................................................. 2
Readjustisting Chair Position/Recline Feature ...................................................................................... 2
Electrical Information.................................................................................................................................... 3
Invacare Wheelchair Base and Joystick .................................................................................................... 3
Battery Information .................................................................................................................................. 3
Accessing Batteries ............................................................................................................................... 3
Recharging batteries ............................................................................................................................. 4
Electrical circuit ......................................................................................................................................... 4
Lifting System ............................................................................................................................................ 4
Limit Switches ....................................................................................................................................... 4
Actuators ............................................................................................................................................... 5
Support System ............................................................................................................................................. 5
Chest Bar ................................................................................................................................................... 5
Shin Pads ................................................................................................................................................... 5
Foot Plate .................................................................................................................................................. 5
Parts list......................................................................................................................................................... 6
GENREAL INFORMATION
HOW TO OPERATE
POWERING THE CHAIR -DRIVE MODE
To ensure the chair is in drive mode, the two drive/push mode switches as well as the drive/lift switch must be in
the drive positions. The two drive/push switches are located at the back of the base of the chair. To engage drive,
these switches must be in the positon towards the inside the chair. Then the system select switch in the blue
control panel located near back cushion must also be switched to drive, or the red position.
Drive
Drive
POWERING THE CHAIR- LIFT MODE
The lift can be engaged by changing the system select switch to the green position. Once the lift system is engaged
the chair can be lowered or risen by pressing the lift system direction switch. If the top of the rocker switch is
pressed down the chair will lift to the standing position until released or until the chair hits one of the limits. If the
lower portion of the rocker-switch is pressed, the chair will lower until in the seated positon or will stop moving if
released before it reaches the sitting position.
**Note: Once user is positioned, in order to drive the electric chair, the drive system must be engaged once again
by changing the system selection switch to the drive system position (red). The user will never be able to change
positions vertically while the drive system is being powered as well.
POSITIONING SUPPORTS
When ready to stand, the chest bar, shin block and seat belt need to be securely fastened. The chest bar should be
rest right up against the user and will withstand any weight placed upon it. The shin block should also be adjusted
to hit the user right below the user’s knees. The shin block should be against the user’s shins while sitting, but not
tight. This prevents pinching when transitioning to standing.
READJUSTISTING CHAIR POSITION/RECLINE FEA TURE
If the chair happen to become out of sync while lifting or lowering, the back seat cushion can be repositioned using
the different limit switches. In order to do this, the bottom limit up switch must be pressed while the lift system up
rocker-switch is being pressed. This will cause the bottom actuator to stop moving while the back actuator
continues to extend or retract.
ELECTRICAL INFORMATION
INVACARE WHEELCHAIR BASE AND JOYSTICK
The wheelchair base used is from a modified Invacare Pronto M91 Rehab version electric wheelchair. Any
information regarding the base can be found at http://www.invacare.com by searching Pronto M91. The Owner’s
manual can also be found at http://www.invacare.com/doc_files/1143153.pdf. In accordance to the standards
Invacare has instilled in its wheelchairs, do not operate on an incline greater than a 12 degrees. This is the
standard wheelchair limit and is also this chairs hard limit. It has been tested and verified to function safely at such
inclines.
BATTERY INFORMATION
Two 12V, 55Ah Duracell AGM batteries are used for both systems. Both the drive system and lift system are
connected to these batteries. The drive system is connected to a total 24V while the lift system operate only on
12V. The picture below shows the connection points for the two different circuits. The yellow and black wires
connected across the upper battery corresponds to the lift circuit while the total 24V circuit connected to the drive
system is connected using the green wires and Anderson clip connectors.
ACCESSING BATTERIES
In order to replace or access the batteries, the lower actuator will need to be removed. In order to do this
the chair must be in the completely lifted position. From here the front most attachment point of the lower
actuator will need to be released. The front attachment point is secured using a pin and bolt. By removing the pin
and bolt the actuator pin will be slide out easily. If there is resistance when attempting to pull out the pin, wiggling
or pivoting the chair differently may need to occur. Then the battery covers must be removed. Once inside the
battery housing, the batteries can be disconnected.
RECHARGING BATTERIES
From testing, the batteries have proven to last much longer than 24 hours. Once the indicator lights on the joystick
signal the battery level is becoming low, the batteries can be recharged using the same battery charger as used
previously. The chair must be turned off and the battery charger connected using the charging port located on the
front of the joystick controller. The charger has an indicator light that will become solid once the batteries have
been fully charged.
ELECTRICAL CIRCUIT
The electrical system is outlined in the figure above. Each wire is also color coded and listed near the associated
wire. In order to insure this circuit works. 8 diodes must be placed within the circuit as shown. These diodes are
critical for proper function and keep the electrical current from shorting places it should not. There are also two
inline fuses placed before each of the actuators. A 3 Amp fuse is placed in line before the back actuator while the
10A fuse is placed before the larger bottom actuator.
LIFTING SYSTEM
LIMIT SWITCHES
There are three limit switches placed on the chair that prevents the chair from moving outside the desired range of
motion. These limit switches are what ultimately stop the chair when it has reaches the desired standing height.
On each limit switch is a physical push button that when hit will completely cut power to the actuators. These limit
switches can be adjusted to account
ACTUATORS
Two actuators are used to position the chair from sitting to standing. Both actuators are made by a medical grade
actuator manufacturer named Linak. The lower actuator is part number is 23910010002000B4 while the smaller
actuator controlling the movement of the back cushion is 343A00+001500B1. The bottom actuator is rated for
10,000 Newtons while the back actuator is 1,500 Newtons. Based on load testing preformed neither the bottom or
back actuator will have any problems withstanding the amount of force being placed on them while lifting and
lowering the user.
SUPPORT SYSTEM
CHEST BAR
The chest bar is connected to the wheelchair via two designated arm bars, which are attached to existing armrests.
It has been predrilled with holes that allow the chest bar to be raised and lowered. This can be achieved by
removing a pin from both the left and right side of the chest bar. The chest bar can then be pinned at any of the
levels where the predrilled holes are located or can be pulled all the way out to be completely removed from the
chair. The arm bars that hold the chest bar have the ability to move horizontally towards and away from the chair
back, allowing the chest bar to be adjusted closer to or further from the user. The left and right arm bars can be
adjusted removing two bolts and screws from each and moving the perforated material to the desired distances
(distance for both the right and left arm bar should be equivalent in comparison to the user’s position). The chest
bar is recommended any time there is a user seated or standing in the chair.
SHIN PADS
The shins pads were designed to hold a majority of the user’s weight, while also providing optimal comfort. The
pads were created to form fit around the users leg. It can be moved vertically higher or lower by removing a pin
and adjusting the perforated tubing to the desired height. The horizontal distance of the shin pad can be adjusted
also by removing a pin and adjusting the perforated tubing on the foot plate to the desired distance. To try to
make the shin pad as versatile as possible, the angle can be adjusted by pinning the bar of the shin pad in the
preferred location.
FOOT PLATE
The Invacare chair base donated to the team came equip with a front hitch. This hitch was able to be utilized as a
connection point for the chairs footplate. The footplate is welded to a bar that is pinned into the hitch. Two
casters were able to be attached to two predrilled holes on the footplate, which provided a dual purpose of
support and anti-tipping.
PARTS LIST
The following are parts used on the chair: most of these parts make up the arm bar, shin pad, foot plate and chest
bar assembly.
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6x- 3/16 inch cap screws (1.5inch long)
19x- ¼ cap screws: 2 (3”); 1(2.5’’), 7 (2’’), 8(.5’’) , and 1 (1’’)
8x – (7/64) cap screws
1x – (5/16) pin & clip
1x – (1/4) pin & clip
2x- (3/32) cap screws (without nuts)
2x- (3/8) shoulder bolt(3’’)
1x- (3/8) shoulder bolt(2.5’’)
2x – Casters (footplate) 4’’ diameter wheel
2x- (3/8) standard bolt (1’’ long)
1 ¼’’ Square perforated tubing for outer arm bar/shin block assembly
1 ‘’ Square perforated tubing for inner arm bar/ shin block assembly
Electrical Parts
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8x- 3amp Diodes
1x- 30V DC, 6Amp red/green selection switch
1x – 30V DC, 6 Amp white rocker switch
3x – Grainger Limit switches
2x – inline fuse holders
1x- 3 A fuse
1x – 10 A fuse