{
  "title": "Hubbard tractor feed - US3825162A",
  "patent": "https://patents.google.com/patent/US3825162A/en",
  "source_figures": [
    2,
    3,
    4,
    5,
    6
  ],
  "pin_pitch_m": 0.0127,
  "sprocket_recesses": 6,
  "belt_pin_count": 16,
  "axle_height_m": 0.016,
  "seconds_per_pitch": 1.2,
  "lid_open_degrees": 103,
  "status": "Visual reconstruction; dimensions, clearances and bend angles are estimates.",
  "shaft_presentation": "Standalone tractor with open bores. External printer drive and guide shafts are omitted; earlier illustrative stubs were removed.",
  "pin_appearance": "Black finish is illustrative. User recalls slightly more pointed pins and possibly white plastic; color is unconfirmed. Current cap follows the spherical segment described in Figures 5-6.",
  "belt_material": {
    "documented": "US3825162A explicitly lists Kapton (DuPont polyimide film) among belt-material options, alongside Mylar, titanium and stainless steel. The description emphasizes flexibility, dimensional stability, repeated bending and heat resistance for molding drive elements onto the belt.",
    "family_history": "Eric recalls that his grandfather encountered the film through work on electrical components for rockets before it was widely available and recognized its suitability for this mechanism. The timing, specific employer, and contractual arrangement have not been independently verified.",
    "reconstruction": "The translucent amber appearance follows Eric's recollection. The production grade and historical film thickness are not established; the model does not simulate Kapton's material properties.",
    "context_source": "https://www.qnityelectronics.com/blogs/dupont-kapton-polyimide-films-the-gold-standard-for-versatility-and-performance.html"
  },
  "meshy": {
    "model": "meshy-t2",
    "mode": "Smart Topology",
    "credits": 5,
    "role": "Separate visual study; moving geometry rebuilt in Blender."
  },
  "web_animation": "Prescribed pin and sprocket motion with paper synchronized to pin pitch; not a physics simulation."
}