Holdown process and system for platen

{
  "publication_number": "US11679601B2",
  "country": "US",
  "kind": "B2",
  "title": "Holdown process and system for platen",
  "abstract": "A method/system of mechanical holdowns allows a substrate sheet in a CBAM (composite-based additive manufacturing technology) process to lie flat during printing. The invention includes a process of mechanically clamping sheets to be printed by a print head to a flat platen using a set of barrel cam driven clamping fingers. The finger supports are attached to the platen and the fingers can be raised and lowered with respect to the platen. Each finger can rotate while swinging downward toward a sheet at the edge of the platen. To clamp the sheet, the fingers are rotated to the perpendicular position and swung lower down to pinch the sheet to the platen. The process can include additional steps that release some, but not all, of the fingers to allow the sheet to relax before re-clamping them.",
  "claims": [
    "1. A print system comprising: a substantially flat print platen bed with a plurality of edge regions; a plurality of finger clamps each comprising a gripping finger supported at the edge regions of the print platen bed; a print head capable of movement across the flat print platen bed; wherein, each finger clamp is constructed and constrained simultaneously both to move vertically with respect to the print platen bed and to rotate horizontally with respect to the print platen bed by means of respective barrel cam actuators that comprise one end effector attached to each gripping finger; the finger clamps having an unclamped configuration when rotated away from the print platen bed and raised above the print platen bed, and a clamped configuration when rotated over the print platen bed and lowered against the print platen bed; further wherein each finger clamp exists in the clamped configuration during movement of the print head across the flat print platen bed.",
    "2. The print platen of claim 1 wherein the print platen bed is substantially rectangular, and there are two edge regions with at least one finger clamp in each edge region.",
    "3. The print platen of claim 2 wherein there are four finger clamps, two at each edge region."
  ],
  "description_excerpt": "The following patents and applications are hereby incorporated by reference in their entireties: U.S. Pat. Nos. 9,776,376, 9,833,949, 10,046,552, 10,252,487, 10,377,080, 10,377,106, 10,384,437 and 10,597,249 and U.S. patent application Ser. Nos. 16/195,362, 16/544,906, 15/923,335, 15/922,158 and 16/711,313.\n\nThe present invention relates to an improvement in the platen in a 3D material printing machine and process, and more particularly to improved holdowns that hold a flat substrate sheet down during processing.\n\nIn the assignee's prior applications and patents (as incorporated by reference above), mechanical and vacuum holdowns were used to hold the sheet in place while it was printed. Vacuum holdowns as described in the earlier disclosure require a vacuum which is expensive, produces significant noise, and uses substantial power. It would be advantageous to have a mechanical holdown that reduces the power consumption and the noise of the machine. In addition, the vacuum may sometimes cause a droplet at the inkjet head to mist, thus causing misprinting and reducing the printable area of the sheet. It would be advantageous to eliminate these problems.\n\nThe present invention is a new method and system of mechanical holdowns which allow a substrate sheet in a CBAM (composite-based additive manufacturing technology) process to lie flat during printing. The invention includes the process of mechanically clamping sheets to be printed by a print head to a flat platen using a set of barrel cam driven clamping fingers. The fingers are attached to the platen and can be raised and lowered with respect to the platen.",
  "cpc": [
    "B41J 11/06",
    "B25B 5/04",
    "B25B 5/062"
  ],
  "ipc": [
    "B25B 5/04",
    "B41J 11/06"
  ],
  "assignees": [
    "Impossible Objects Inc"
  ],
  "inventors": [
    "Robert Swartz",
    "Eugene Gore",
    "Drew Marschner"
  ],
  "filing_date": "2020-05-16",
  "publication_date": "2023-06-20",
  "grant_date": "2023-06-20",
  "priority_date": "2019-05-16",
  "application_number": "US-202016876035-A",
  "family_id": "73651411",
  "cited_by_count": 0,
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}