Security lock for door

{
  "publication_number": "US11015376B2",
  "country": "US",
  "kind": "B2",
  "title": "Security lock for door",
  "abstract": "A security lock for a door is provided having a bracket on the interior side of the door with a locking bolt mounted in the bracket. The bolt is adapted for movement between a raised, unlocked position above a cavity on the floor below the bracket and a lowered, locked position where the bolt is in the cavity to prevent the door from being opened. A bolt restraint is mounted on the bracket and cooperates with the bracket to maintain the bolt in its unlocked position. The bolt restraint, for example, a spring-loaded ball that engages an annular recess in the bolt, releases the bolt into its locked position when a downward force is applied to the bolt. The locking bolt has an enlarged flange that stops movement of the bolt into the cavity beyond a predetermined location on the bolt.",
  "claims": [
    "1. A security lock for a door, comprising; (a) a bracket for being secured to an interior side of the door proximate a bottom of the door; (b) a locking bolt for being mounted in the bracket and adapted for manual movement between a raised, unlocked position above a cavity positioned below the bracket in a floor without the use of a force multiplier, and a lowered, locked position without the use of a force multiplier, with the bolt positioned in the cavity to prevent the door from being opened; (c) a laterally-operating bolt restraint mounted on the bracket and laterally-engaging a sidewall of the bolt for maintaining the bolt in the unlocked position above the cavity and adapted to release the bolt for movement into its lowered, locked position upon a downward force being applied to the bolt; (d) the locking bolt including an enlarged flange adapted to stop movement of the bolt into the cavity beyond a predetermined location on the bolt; (e) a protective bushing adapted for being fitted into the cavity in the floor for receiving the bolt; and (f) an unlocking tool having a thin, curved strip including an opening in a first end of the strip and adapted to fit onto the bolt at a location below the flange and adapted for being inserted under and through an existing space between floor and the door from a position proximate to an exterior side of the door and manually operated to engage the enlarged flange of the locking bolt to lever the bolt upwardly out of the cavity into the unlocked position without damage to the lock or the door.",
    "2. A security lock for a door according to claim 1, wherein the bolt includes an annular recess in the bolt at a location along a length of the bolt such that the annular recess communicates with the laterally-extending bolt restraint to maintain the bolt in the unlocked position and is adapted to release the bolt by downward pressure applied to the bolt sufficient to overcome interference between the bolt restraint and the annular recess.",
    "3. A security lock for a door according to claim 1, wherein the bolt restraint comprises a spring carried by the bracket and a ball urged by the spring to partially reside in the annular recess and apply a perpendicular interference force to the annular recess for maintaining the bolt in the unlocked position."
  ],
  "description_excerpt": "This invention relates to a security lock for use on a door, such as a classroom door, to prevent entry by an unwelcome intruder. More particularly, the invention pertains to a security lock that can be locked from inside of the classroom in an emergency situation and later unlocked from the outside of the door using a special tool.\n\nSchool shooting events have garnered wide publicity in recent years. In some tragic events, students were trapped inside classrooms, unable to bar entry to an intruder. This concern has spurred discussion and media attention about protecting students in the classroom. One such avenue of discussion revolves around teachers and students securing themselves inside of classrooms.\n\nTraditional doorknob locks are often installed such that they lock from the outside of a door rather than from the inside. Other classrooms do not have locks installed on the classroom doors at all. Replacing existing locks on all classroom doors can be costly and time consuming.\n\nOther types of common door locks, such as barrel bolts and latches as well as recent aftermarket door locking devices pose safety concerns due to the inability to unlock the door from the outside by school personnel or law enforcement. Additionally, local fire safety standards often limit the types of safety mechanisms and locking hardware that are allowed to be installed on classroom doors.\n\nIt is therefore an object of the present invention to provide a door locking mechanism that can be engaged quickly and easily in the event of an attempted intruder into a classroom.",
  "cpc": [
    "E05C 19/003",
    "E05B 19/20",
    "E05B 2063/0039",
    "E05B 35/008",
    "E05B 63/18",
    "E05C 1/04",
    "E05C 17/48"
  ],
  "ipc": [
    "E05B 35/00",
    "E05B 63/18",
    "E05C 1/04",
    "E05C 19/00",
    "E05B 19/20",
    "E05C 17/48"
  ],
  "inventors": [
    "David Daniel Rankin, Sr."
  ],
  "filing_date": "2018-06-15",
  "publication_date": "2021-05-25",
  "grant_date": "2021-05-25",
  "priority_date": "2018-02-23",
  "application_number": "US-201816009551-A",
  "family_id": "63294063",
  "cited_by_count": 4,
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}