Automatic door operator
AssigneeAutomatic Doorman, Inc.
InventorHoward L. Beckerman
Life of this patent
Estimating the term…
Abstract
An automatic door operator system is provided with a first potentiometer having its wiper arm coupled to a pivoting member whose angular position varies in accordance with the magnitude and direction of an obstructive load applied to the door. A second potentiometer is provided having its wiper arm coupled to a movable member whose position corresponds to the position of the door. The potentiometers are connected as voltage dividers and the voltages provided at their wiper arms are utilized for controlling the movement of the door.
Claims19
An operator for moving a door between first and second positions including a selectively energizable reversible electric motor, drive means for coupling said motor to said door, means for providing a contact closure signal, and control means responsive to the occurrence of a contact closure signal when said door is in one of said first and second positions for energizing said motor to move said door toward the other of said first and second positions, wherein the improvement comprises:
- means coupled to said drive means for generating a force signal having a magnitude directly corresponding to the instantaneous magnitude of the force opposing movement of said door;
- differentiation means for measuring the magnitude of the instantaneous rate of change of said force signal with respect to time and providing an obstruction signal related thereto;
- and
- safety means responsive to said obstruction signal exceeding a predetermined threshold value for causing said control means to deenergize said motor.
An operator for moving a door between first and second positions comprising:
- a selectively energizable reversible electric motor;
- drive means for coupling said motor to said door;
- means for providing a contact closure signal;
- control means responsive to the occurrence of a contact closure signal when said door is in one of said first and second positions for energizing said motor to move said door toward the other of said first and second positions;
- obstruction sensing means for providing an obstruction signal in response to an excessive force opposing movement of said door;
- reversal means included in said control means and responsive to the occurrence of either a contact closure signal or an obstruction signal when said door is being moved toward said first position for energizing said motor to move said door back toward said second position;
- means coupled to said drive means for generating a position voltage which is predictably related to the position of said door;
- means for defining a range of voltages having a first limit corresponding to said first position and a second limit corresponding to said second position;
- means for defining a third limit voltage within said range, said third limit voltage differing from said first limit voltage by a fixed amount corresponding to a fixed travel distance of said door;
- and
- means responsive to said position voltage being between said first and third limit voltages for preventing operation of said reversal means.
Dependencies are inferred from the claim text.