Page Comparison

2 Bar Linkage Mechanism with “Bird’s Mouth” Lock

• Bird’s Mouth Lock system shown in research section above can be simplified down

  • Simplified version utilizes only a flange to keep the two bars from rotating (thus locking them in place and propping the trunk)

    • 

    • Above image shows an exploded view of the simplified mechanism

    • Below is a video of the theoretical motion of the system

      • NOTE: GRAVITY IS NOT SIMULATED IN THE VIDEO SHOWN - THIS MAY AFFECT THE FINAL MOTION OF THE SYSTEM

      • 2 Bar Linkage with Bird's Mouth Lock Motion (3).wmv

        • Considerations:

          • When locking (i.e. pushing down on the top linkage to engage with the flange), steps must be taken so the linkage translates diagonally down (as opposed to rotating about its mounting point) so that it properly engages the flange

          • To do so: the rotation point could be tightly secured

          • When closing, the two linkages should fold into each other, we are assuming gravity will pull the bottom linkage down and thus provide this motion but this is an assumption

Compressed Air Support Strut

• Considerations

  • Generally support struts are used in pairs

    • This will result in even distribution of force (as both sides of whatever item is being supported are receiving the force exerted by the support struts)

    Support strut will exert a force that is greater than the force exerted by the mass of the trunk

    When closed the compressed air support strut is constantly exerting a force that will try to open up the trunk

  • Latch must be able to withstand this force (though this shouldn’t really be an issue unless the support struts being used are overspecc'ed by a large amount - which should not happen)

  This constant force will result in a residual stress buildup in the mounting area of the trunk

  Must consider if this will cause elastic / plastic deformation of the trunk panel

  While this shouldn’t happen (as the magnitude of force is quite low) it should still be considered

  • When the trunk is in the open position, the compressed air struts will be exerting a force greater than the force from the mass of the trunk

    • Must consider if this will potentially damage solar cells

      • We know pressure should not be exerted onto the solar cells from the top - but could pressure from the bottom be an issue?

• Preliminary Motion Analysis

  • Conducted using McMaster-Carr gas strut (12.2” extended length, 8.26” compressed length), with placeholder trunk and side panels

  • Note: This initial test was done with a flat trunk panel placeholder, the actual trunk panel is not flat

  • Early results:

    • Gas struts can be mounted within our vehicle architecture and still produce desired results

      • Compressed Air Strut Motion.wmv

        • Note: The compressed air strut should be PARALLEL to the trunk in the closed position. This should be done so that when the trunk is unlocked it does not immediately open (because force of the strut will be acting parallel to the trunk)

          • This will avoid any potential accidents where the trunk is unlocked while there is an obstruction above the trunk and hits it while opening - which would result in serious damage to the solar cells

• Unconventional Mounting (if needed)

  • If the the mounting point of the trunk is not in line with the rotation point of the trunk (unlike how it is in the test above) the strut must be slightly extended when the trunk is closed

    • This will allow for the necessary slight compression of the strut when the trunk first opens up

    • 

      • The circle represents the path of the mounting point. When the trunk first opens up, it will travel up and away from the pivot point, thus requiring the strut to compress

      • Also note how the strut is slightly extended when the trunk is in its closed position (as described previously)