Patents Assigned to Freight Guard Industries
  • Patent number: 4083424
    Abstract: A push-button keyboard is located on the dashboard of a truck for unlocking a rear access door to rear cargo space in the truck. Selected ones of the keys are sequentially operated in accord with a given combination generating a signal which throws a lock bolt as by means of a solenoid. A first timer prevents operation of the lock unless the combination keys are operated within a first given time interval. A second timer automatically releases the solenoid operated lock bolt after a second given interval of time has elapsed to relock the access door in the event it has not been opened. The signal to the solenoid operated bolt itself is frequency coded to inhibit introduction of unauthorized signals in an unauthorized attempt to operate the lock.
    Type: Grant
    Filed: February 9, 1977
    Date of Patent: April 11, 1978
    Assignee: Freight Guard Industries
    Inventors: Alfons von den Stemmen, John R. Swartz