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• The telescoping mechanism allows the linear distance of the steering wheel to be adjusted by the driver.
• This system adjusts incrementally. It is not infinitely adjusting.
  • Infinitely adjusting systems allow for the shaft to be adjusted to any distance within a given range. Incremental adjusting systems only allow the user to adjust to specific locations along the shaft (picture gym equipment).
  • An infinitely incrementally adjusting system was not used instead of an infinitely adjusting system; a significant amount of friction would have been required infinitely adjusting systems require a large frictional force to allow the telescoping shaft to rotate without backlash (allow it to rotate at the exact same speed as the collapsible column).
  Backlash or play is expected with this system. This is resolved by using a D-shaft (from here) for the telescoping mechanism
• Parts:
  1. Telescoping Shaft
     
     • Purpose: to allow the driver to adjust the wheel forward and backward relative to them. The total telescoping range was set by interiors to be 6".
     • It is a 7" long 3/4" shaft rigidly attached to the quick release of the steering wheel on one side and nothing else on the other side. It sits inside the collapsible column.
     • A D-shaft (from here) was used to make this.
       • A D-shaft was chosen
  arbitrarily out of the choices of non-circular shafts. Either
  1. • • specifically as it is the cheapest out of the partially circular shaft options. A partially circular shaft was chosen to allow the telescoping shaft to fit inside the quick release.
       • The outer diameter was chosen to be 3/4" to allow for more affordable quick-release options. 3/4" is a common shaft diameter.
       • Note: Any non-circular shaft (i.e. a D-shaft, a keyed/ partially keyed shaft,
  or
  1. • • a splined shaft, a hex shaft, etc.) could have been used. Non-circular shafts minimize backlash.
       • The length is 7" to allow part of the shaft to be supported by the collapsible column while it is extended to its limit (6").
     • There are 12 x 3 mm OD holes in the telescoping shaft, each spaced 10 mm apart.
     • 12 holes and 10 mm are both arbitrary numbers.
     • The holes are 3 mm in diameter to allow the nose of the spring plunger to fit in them.
  2. Collapsible Column
     • Purpose: to hold the telescoping shaft, the spring plunger, and the spring plunger's mount in place.
     • It is a hollow, D-shaped , 7" shaft, pin-connected to the telescoping shaft on the end closer to the steering wheel, and welded/rigidly attached to a 5/8" shaft on the end near the U-joint.
       • It is D-shaped to accommodate the telescoping shaft shape.
       • The outer diameter is D-shaped as well (i.e. there is one flat surface) to allow a mount for the spring plunger to be attached to it.
       • Its inner diameter fits the telescoping shaft's outer diameter exactly to minimize backlash.
       • Its wall thickness of 1/8" and its top surface width of 1/2" are both arbitrary.
     • It has a 6 mm OD hole on the flat surface, with its center being 20 mm away from the nearest edge.
       • The hole diameter is 6 mm to fit the M6 screw body of the spring plunger.
       • The distance of 20 mm is arbitrary.
  3. Spring Plunger
     • Purpose:
       1. Lock the axial and rotational motion of the telescoping shaft relative to the collapsible column while the car is in motion (i.e. while steering is happening).
       2. Allowing the user to easily adjust the telescoping shaft axially while the car is not in motion.
       3. Act as a shear pin in the event of a crash. The spring plunger would shear into 2 separate parts, allowing the telescoping shaft to collapse into the collapsible column, which would prevent the driver from being impaled.

• The current design uses 1 spring plunger (from here) which is initially loaded in compression. It fits into holes spaced ____mm apart. 
  • The hole spacing is arbitrary.
  • The hole is not conical since it does not significantly reduce backlash if the hole aids the spring plunger in centering itself within the hole. The main thing which aids against rotational backlash if the non-circular telescoping shaft.
• The spring plungers will act as the shear pins required for collapsibility in the event of a collision.
  • In a collision, the force will travel through the front of the car to the lower column (held in place by the steering column mounting), through the U-joint, and through the upper column, which will cause the spring plungers to fail by the shear stress loading. This prevents the driver from being impaled.
• The collapsible column holds the telescoping shaft in place. The spring plunger is attached outside of it using a mount.
  • The mount is to be manufactured out of a small piece of metal.
  • The collapsible column is D-shaped (both inside and out). It may be manufactured via the following process:
    1. Make a hole axially through the shaft.
    2. From one side, mill the hole to have a D-shape. Repeat with the other side. This is done in 2 parts since the shaft may be too long to be milled in one step.
    3. Mill off the top surface to be flat.
    4. Tap a ___mm diameter hole through the side for the spring plunger to go through.
    5. Tap 4 more holes of __mm diameter for the mounting part to sit on.
    6. Screw on the mount with the plunger inside.

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