5. Assembly
5a. Mechanical
Let this section begin with a warning: Everything in the design has been dimensioned, and had materials specified for it for a very specific reason. Don’t change the basic frame design or use unapproved materials – this could result in the creation of a chair that at best does not function, or at worst is very dangerous to the occupant!
Some useful tips on assembly and manufacture:
1) Talk with the end user! This is the most important part of the manufacturing process. Discuss things like padding, mounting of communication devices, controls, and body geometry, so that the end product is something they enjoy using, and that you are proud to have built.
2) Trial fit everything before welding. This helps to ensure that the final product will go together exactly the way it was designed to. Tack welds may be used when necessary to help hold the frame(s) together for measurement setup, etc.
3) Try to use new material whenever possible. This eliminates the possibility that incorrectly identified old material of incorrect composition will be used.
4) Make the Acme screw/gearbox/motor assembly first – this is the heart of the entire chair, and any adaptations that will need to be made to accommodate it should be seen and dealt with early on.
5) Don’t make mounting brackets, etc. for the commercial parts until they are in hand. This will eliminate costly, time-consuming mistakes, as well as ensuring that the correct parts have been ordered.
6) Don’t try to make the gearboxes out of aluminum billet. ½” or 7/16” plate, fitted and pinned together with steel dowel pins and screws, is not only very strong, but much simpler to work with. Trying to weld the gearbox components will result in excessive warpage. The gearboxes should be held to close tolerances (+/- 0.005”)
7) Make the hinges out of steel billet. This was found to be the simplest and most economical method.
Assembly Instructions
(General)
This section will discuss general assembly instructions. Specific fabrication methods, tools, and processes will be left up to the builder, as it is assumed that he/she will be sufficiently experienced and competent to know how to produce parts from blueprints.
1) Begin with the Acme screw/gearbox/motor assembly. In our case, this was salvaged from a Nissan 300ZX power bucket seat. It should include the motor, Acme screws, two right-angle gearboxes, a center link, and two followers (plastic insert with steel holder).
2) Make a pair of reduction gearboxes as per the blueprints
3) Fit the reduction gearboxes to the Acme screw/gearbox/motor assembly. This will require turning the Acme screws down.
4) Make the shortened center link.
5) Make the center link and pillow blocks as per the blueprints. Test fit these parts to the Acme screw/gearbox/motor assembly.
6) Make the base frame. After cutting the appropriate pieces, tack weld and square them so that the Acme screw/gearbox/motor assembly may be test fitted. Finish weld only after this test fit is successful. Make sure to minimize warpage and distortion on the shear panel by stitch welding.
7) Make the hinges. As the seat is rather more of a custom item, talk with the end user about desired angle settings. These may be put wherever the end user desires to have them.
8) Make the seat bottom and back frames. Very slight modifications may be made to accommodate the needs of different users regarding augmentative communication devices, control switches, etc., but the basic design and dimensions should remain the same.
9) Test fit the seat frames to the hinges. Test fit this assembly to the base frame and check for clearance with the Acme screw/gearbox/motor assembly.
10) Make and test fit the lift arms.
11) Make and test fit the attachment points for the air cylinders. Air cylinders of this type are available at almost any large auto parts store (NAPA, Pep Boys, Kragen/Schucks, Checker).
12) Final weld the seat frame. Use a press to push the frame back into shape if it warps.
13) Make the spreader bar. This should fit SNUGLY between the two hinges – if it is too tight, it could impede the mechanism, while excessive looseness will result in a sloppy fit for the seat and base frame interface.
14) Bolt the seat together, remembering to install any specialized occupant restraints, etc. that may be used. Test the seat with a load in it, similar in size to the end user.
15) Make the upholstery for the seat. A strong, durable fabric such as Cordura ™ nylon is the best, as it has good strength and is easy to keep clean.
16) Degrease, primer, and paint the seat. Almost any durable coating may be used (powder coating, chrome plating, paint, rubberized bedliner-type coating), but remember to take the Acme screw/gearbox/motor assembly out before application, as coating material will cause the gears to mate incorrectly if it gets on them.
17) Reassemble
the seat, and test it once again, this time with the end user in it. After ensuring proper function, show the
attendant(s) the proper lubricating points, and go over the maintenance and
cleaning procedures with them.
5b. Electrical
The following components are needed to construct the chair’s electrical system:
4 12VDC 20A relays
2 DPDT 12VDC 10A toggle switches
1 Head switch
1 30A fuse holder
1 1A fuse holder
1 lighted kill switch
2 enclosures
1 motion cutoff switch
1 cig. Lighter plug
1 6 pin disconnect plug
2 mono receptacles
18ga insulated primary wire
24ga insulated primary wire
1 heavy 2 pin disconnect
One enclosure will serve as the systems relay box and the other will serve as the systems control box. In the relay box, the 4 relays will be placed, and their joints soldered and covered either with heat shrink tubing or Eastwood Liquid Electrical Tape to prevent the possibility of short circuits. The light duty circuits (terminals A and B) on the relays and all wires connecting the selector and attendant switch are to be wire with 24ga wire since they only carry about 100mA. The motor circuit will be wired with 18ga wire due to its heavier amp load. The relay box will also house the low amperage fuse, the mono connections to connect to the head switch and will connect to the control box with the specified 6 pin disconnect plug. This includes all wiring from the numbered pins of the relays, the supply circuit and the motor wiring circuit. The control box will house the high amperage fuse, the selector switch, the attendant switch, and the lighted kill switch. The heavy 2 pin disconnect will connect the high amperage circuits between the control and relay boxes. The cigarette lighter plug will provide the voltage source.
6. Operation
6a. Seat Operating Instructions
The first thing to remember when using the seat is that every guard, cover, and fuse is there for a very good reason. Don’t remove or attempt to operate the seat without them!
Controls for the EZ
Journey Car Seat
There are 3 (three) switches used to control the seat, in addition to the head switches.
The first is the “KILL” switch, used for turning the chair’s power on and off, and for emergency shut downs. This is a large, red switch that will light up when the seat is turned on.
The second is the “USER/ATTENDANT” switch, used to switch control of the chairs reclining function between the user’s head switch and the attendant’s control switch. It may also be used to deactivate the head switches if the user wants to use the headrest without triggering the switches. This switch is labeled.
The third is the “ATTENDANT” control switch. This is used to allow the attendant to have full control over the chair's recline function and will only function when the “USER/ATTENDANT” switch is in the Attendant position.
1) Unfold the seat by pulling the hinge pins out from the hinge until they are fully disengaged, and then setting the seat back to the desired angle. Reinsert the pins, taking care to ensure that they lock FULLY (they will click).
2) To allow the EZ Journey Car Seat maximum operating room, recline the vehicle seat as far back as it will go and slide the car seat as far back as possible, if feasible.
3) Place the EZ-Journey car seat, facing forward, in the passenger seat of the vehicle. Make sure that the car seat fits the vehicle seat (i.e. it does not have excessive overhang, and allows for sufficient head and leg room).
4) Adjust the limited tilt mechanism by removing the pin in the limited tilt mechanism hinge. Adjust this bar to press against the back of the vehicle seat by first getting it as close as possible with the hinge settings, and then bringing the vehicle seat back up to meet it.
5) Insert the seat belt by first unfastening the hook and loop straps on the rear restraint connection, and then passing the lap portion of the belt under the angled plate so that it sits flat against the vertical part of the rear restraint connection. Fasten the belt to the buckle as would be done normally, and reattach the hook and loop straps to ensure that the vehicle seat belt is held in place securely (Note the above instructions apply to three-point, retractable seat belts (shoulder-type belts) and retractable lap belts. For lap belts that buckle, simply put the two halves of the belt into the seat-belt retention device, buckle them, and tighten them down as it would be done normally).
6) Plug the power cord into the battery pack or the vehicle cigarette lighter outlet whichever is available.
7) Turn the large red “KILL” switch on. It should light up if the chair is getting power.
8) Load the occupant, and buckle the occupant safety belt.
9) Make any adjustments necessary for the occupant’s comfort, position any extraneous equipment that the occupant requires, and turn the control switch from “ATTENDANT” to “USER”.
After returning the
seat to its original position, follow the instructions given for putting the
seat in a vehicle (above) in reverse order.
6b. Seat Maintenance
1) Place the seat on a level surface. Attach the power pack and use the “ATTENDANT” control switch to recline the seat to its maximum. DISCONNECT THE POWER IMMEDIATELY AFTER THIS TO AVOID INJURY!
2) Remove the seat back by separating the hook and loop strips holding it to the seat back frame.
3) Remove the head switch cover by separating the hook and loop strips and pulling it off of the head switch.
4) Remove the J-2 seat cushion by pulling it off, separating the hook and loop strips on the frame from those on the cushion. Remove the fabric cover of the J-2 seat cushion.
5) Remove the fabric mechanism cover by separating the hook and loop strips on the cover from those on the frame. Be careful not to allow anything to fall into the reclining mechanism.
1) Place all fabric components in the washer. Wash COLD with no bleach, GENTLE cycle. Allow components to air dry.
2) Vacuum the seat frame out. Some things will collect there, despite the mechanism cover. Take car to not damage the reclining mechanism with the vacuum nozzle. Take care of any spills, etc. with a gentle spray cleaner and paper towels.
3) Clean the J-2 seat cushion as per the manufacturer’s instructions.
4) Reassemble the seat by reversing the order of the instructions detailed in Disassembling the Seat for Cleaning (above).
Sometimes, a more complete disassembly may prove to be necessary, as in the case of seat belt replacement or general repairs.
1) Follow steps 1-5 given in the section Disassembling the Seat for Cleaning (above).
2) After all of the fabric has been removed from the seat, unbolt and remove the air cylinders under the seat. This will require use of a small prybar, and should be done very carefully, as these cylinders are under pressure. Unbolt first one end, remove the end of the cylinder from it bracket, and allow it to extend to its full length. IT MAY EXTEND QUICKLY AND WITHOUT WARNING. Unbolt the other end, and set the cylinders aside with their mounting bolts.
3) Unbolt the lift arms, beginning with the end that is attached to the seat. Let the seat recline all the way back to a rest position without letting it fall (this may cause damage to the head switches). Next, unbolt the lift arms from the mechanism center piece. Set the lift arms aside with their bolts. Note that one is stamped with a “L” for left side, and the other one goes on the right.
4) Remove the 5/8 in. pivot bolts from the hinges. This will allow the center bar to drop out from between the hinges. Lay the center bar and the two bolts aside. Note that one end is stamped with a “L” for left side.
5) The seat assembly may now be lifted out. The two halves of the seat WILL NOT come apart, as the hinge design locks them together for safety. Trying to separate them will result in severe damage to the seat!
NOTE: The following steps should be performed by a professional machinist or mechanic – proper alignment of the gears is vital to the seat’s continued operation!
6) Flip the base frame over. Remove the reclining mechanisms gearbox bolts on the underside of the seat to remove the mechanism. Be very careful not to drop or misplace any of the shims or bolts belonging to this mechanism – they are vital to the operation of the chair. Be careful not to over bend the small coupling between the motor and the gearbox. Set these parts aside.
7) Flip the base frame over again and remove the ends of the Acme screws from the end bushings near the front of the chair. Unbolt the bushings and set these parts aside.
8) Remove the center link joining the motor to the gearboxes.
1) Reassemble the seat by reversing the order of the instructions detailed in Total Disassembly of the Seat (above).
1) The seat should be cleaned regularly (see Disassembling the Seat for Cleaning and the Cleaning the seat)
2) The hinges should be lubricated on a weekly basis by spraying a lubricant (such as lithium based grease) into the adjustment pin holes, and working them back and forth.
3) The gears, Acme screws, lift arms, and followers should be lubricated every two days of use by spraying them with a lubricant (such as the lithium-based grease used above) and cycling the mechanism.
4) The pull pins for the hinges should be lubricated whenever necessary with a light oil, such as WD-40 ™.
5) Don’t forget to keep extra fuses on hand, in case one blows out. Only replace fuses with those rated for the same voltage and current. Auto parts stores are good sources for BUSS type fuses.
6c. Warnings/Restrictions
The following is a list of things that must be given serious attention. This list is in conjuncture with all previous warnings and guidelines mentioned in this report. IT IS VERY IMPORTANT TO THE SAFETY OF THE OCCUPANT OF THE EZ JOURNEY CAR SEAT THAT THE WARNINGS AND RESTRICTIONS ARE READ AND UNDERSTOOD AND FOLLOWED.
1) Under no circumstances is the EZ Journey Car Seat to be used in the front seat of a vehicle that is equipped with an airbag that cannot be deactivated. If the EZ Journey Car Seat is used in the front seat of a vehicle with an air bag it must be turned off or deactivated so that it will not deploy during an impact of any nature. IF AN AIRBAG IS DEPLOYED UPON THE PASSENGER WHILE THEY ARE USING THE EZ JOURNEY CAR SEAT THEY MAY SUFFER SERIOUS INJURY.
2) The EZ Journey must only be used in a vehicle while it is properly restrained by one of the vehicle’s safety restraints. If one of the vehicle’s existing safety restraints cannot be used to secure the EZ Journey to the seat then it is not to be used in that vehicle.
3) The EZ Journey may be used on an airplane but the attendant flying with user should ask a customer service representative of the airline if the EZ Journey will be allowed on the flight prior to the flight.
4) If the EZ Journey begins making strange noise during use it should be immediately shut down and unplugged from its power source. The occupant should then be removed as soon as possible and the chair examined. If the problem cannot be found the chair is to be examined by machinist or a member of DDI before it is used again.
5) If the EZ Journey ever begins to give off a burning smell it is to be immediately shut down and unplugged from its power source. The occupant should then be removed as soon as possible and the chair examined.
6) If use of the EZ Journey Car Seat makes it difficult for the driver of the vehicle to drive safely it should not be used or it should be moved to a location in the vehicle were it does not impair the drivers ability to drive safely.
7) Follow all maintenance instructions.