{
  "patent_number": "US 3826068",
  "country": "US",
  "title": "How the String Trimmer (Weed Eater) Actually Cuts Grass",
  "original_title": "Rotary cutting assembly",
  "summary": "This 1974 patent describes the mechanics of using a high-speed spinning plastic line to cut grass, replacing dangerous metal blades with flexible, non-metallic material.",
  "what_it_does": "The patent defines a rotary cutting tool that uses a flexible, non-metallic line to trim vegetation. The core mechanism involves rotating this line at a specific tip velocity, calculated based on the line's thickness (diameter), to ensure it cuts grass effectively without being dangerous to the operator. The apparatus includes a housing that stores the line, allowing it to extend through an aperture while spinning. By controlling the relationship between the line's diameter and its rotational speed, the device achieves enough energy to slice through plant stems while remaining safer than a rigid metal blade.",
  "what_it_does_not_cover": [
    "Does not cover cutting tools that use rigid metal blades or discs.",
    "Does not cover systems where the line is not flexible or non-metallic.",
    "Does not cover rotation speeds that fall outside the specific mathematical range defined by the line's diameter.",
    "Does not cover manual or non-rotary cutting tools."
  ],
  "filed": "1973-01-08",
  "granted": "1974-07-30",
  "expires": "1993-01-08",
  "status": "expired",
  "holder": "Individual",
  "holder_url": "https://patentbrief.org/company/individual",
  "inventors": [
    {
      "name": "G Ballas",
      "url": "https://patentbrief.org/inventor/g-ballas"
    },
    {
      "name": "T Geist",
      "url": "https://patentbrief.org/inventor/t-geist"
    }
  ],
  "times_cited": 86,
  "tags": [
    "consumer_electronics",
    "mechanical"
  ],
  "abstract": "Apparatus is provided with a plurality of flexible non-metallic cutting members for cutting and trimming vegetation, and the like, in a manner to reduce or eliminate the chance of injury or damage to adjacent persons or property. Maximum cutting effectiveness is achieved with a minimum sacrifice of safety by rotating the cutting members at a tip velocity which is a function of the cross sectional diameters.",
  "url": "https://patentbrief.org/patent/us/3826068/weed-eater-string-trimmer",
  "markdown_url": "https://patentbrief.org/patent/us/3826068/weed-eater-string-trimmer/md",
  "google_patents_url": "https://patents.google.com/patent/US3826068",
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}