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  • Selected concept based on further research and feasibility analysis: Compressed air struts

Main reasons:

  1. Ease of use

  2. Ease of implementation

  3. Manufacturing time

Ease of Use (1)

Based on the research done in the previous section, it was evident that the user interaction would be much easier and streamlined with the compressed air struts compared to the 2 bar linkage system.

To open the trunk (if compressed air struts are used) the user would merely need to unlock the trunk latch and lift the trunk. From there the compressed air struts will prop the trunk open and keep it open. To close the trunk the user merely needs to pull down on the trunk panel and lock the latch.

In contrast to this, the 2 bar linkage system would require the user to unlock the trunk latch, lift the trunk and then slightly lower Compressed Air Strut:

  • Opening the trunk: User unlocks trunk latch and lifts trunk. Compressed air struts prop trunk and keep it open (no user interaction needed beyond lifting of trunk)

  • Closing of trunk: User pulls down to close trunk panel, locks trunk latch

2 Bar Linkage System:

  • Opening the trunk: User unlocks trunk latch and must lift trunk for entirety of its range of motion. User then needs to slightly lower the trunk to engage the “Bird’s Mouth” Lock

. To close

  • Closing the trunk

the user would need

  • : User needs to raise the trunk panel slightly to disengage the “Bird’s Mouth” Lock

before closing the trunk. This process may not be intuitive and is cumbersome.

  • . User then pulls down to close trunk panel, locks trunk latch

2 Bar linkage system’s process is: lengthy, not intuitive and cumbersome

Ease of Implementation (2)

As can be seen in the previous section, there were notable concerns with the 2 bar linkage system. From the basic assembly created (which

2 Bar Linkage system - Locking (to keep Trunk open):

  • Basic assembly did not account for

the force of gravity), it was

  • gravity. Therefore hard to verify if the “Bird’s Mouth”

lock

  • Lock could easilybe engaged.

    • There were some cases where the top bar may not translate diagonally and could instead rotate. This would not properly engage the “Bird’s Mouth” lock

and

    • In the end more testing would be required

for this.In addition, there was a concern in the closing motion. Without the force of gravity being accounted for in the basic assembly, it was hard

2 Bar Linkage system - Unlocking (to close Trunk):

  • Basic assembly did not account for gravity. Hard to verify if gravity would

be enough to cause the

  • pull bottom bar

to naturally fall down (remember it is pin connected to the top bar) and rotate, thus causing the whole 2 bar linkage to fold properly as the trunk is lowered.

To conclude, it was difficult to determine if the ideal motion of the 2 bar linkage would happen in reality and if it didn’t would require even more user input to make the entire linkage system close properly. More testing would be required (likely a SolidWorks motion study, but this seemed to be incompatible with the slot mate used to define the pin connection between the bars AND/OR creating a scaled down version in real life) and this would complicate and lengthen the implementation process.

On the other hand, basic hand calculations were used to verify that the two compressed air struts would be enough to support the trunk panel (in fact just one compressed air strut was shown to be enough) and that a user could easily close the trunk (in

  • down and for the entire assembly to fold into itself (like how it was shown in the video)

    • Again more testing would be required if this would happen in real life

2 Bar Linkage system - Summary:

  • Need to conduct more testing, making design process longer

    • Could use SolidWorks motion study to account for gravity

      • But the slot mate used to connect top and bottom bars was not compatible with motion study

    • Could build scaled down model

Compressed Air strut - Summary:

  • Used hand calculations to verify struts could keep the trunk open

    • To be safe, each one of the struts can keep the trunk open

      • Therefore even if one fails, the other will be enough to ensure trunk stays open

  • Used hand calculations to verify user could easily close trunk

    • In accordance with OSHA guidelines for allowable pulling forces one can exert

)

  • Overall more confident that it can work as intended as opposed to 2 Bar Linkage system which still had major uncertainties

Manufacturing Time (3)

If the 2 Bar linkage system were to be implemented, it would need to be manufactured as well. While the geometry would be basic, there would still need to be time allocated to manufacture the parts as well as assembling them together. On the other hand, the compressed air strut would be bought, and the only time required would be the shipping time. In addition not needing to manufacture it in house would free up some of our manufacturing resources. Important to note is that the compressed air struts were also Linkage system:

  • Simple geometry but would still require manufacturing and assembly time

  • Would also take up manufacturing resources

    • Regardless of if we do it in-house or outsource it, it is a manufacturing resource that is being used

Compressed Air strut:

  • Would not need to be manufactured

    • Only the mounts need to be manufactured

      • But those need to be manufactured for 2 Bar Linkage system as well

  • Frees up manufacturing resources

  • Was reasonably priced (approximately $63.00 CAD for a set of two from McMaster-Carr)

, thus

    • Therefore price was not an issue

, in this case.