Abstract: A door operator for an overhead garage door having a reversible electric motor and a gear train driving the door. Limit stops are provided, one for the "up" limit and another for the "down" limit. Each of the limit stops is independently zero setable to cut off current to the motor at a pre-selected position.

Abstract: Door operator device comprising an indicator that the door is in either fully opened or fully closed condition, including a drive for moving the door to these positions in response to operation of an initiator connected therewith. The device includes a switch circuit to switch off the drive when the door has reached either of the positions, and the indicator is operatively interconnectable with the door operator device to provide the information that the door is in its fully opened or closed condition.

Abstract: A door is provided having an automatic opening means for the door and a key locking facility for mechanically locking the door in a door closed position and electric circuit means connected with the motor means to sense a change in the electrical operating conditions of the motor above that which is normal for operation of the motor and to remove the above normal power thereby supplied to the motor in such circumstances.The sensing means preferably comprises a means which switches off the power once the electrical operating conditions are sensed above that which is normal and whereby it returns the power some time later and should the motor then reexperience electrical operating conditions above that which is normal the sensing means will again switch off the power to the motor.The sensing means desirably comprise a bimetallic cut out switch means.

Abstract: A mullion section member is disclosed for fitting between a pair of adjacent roller shutter doors in a door opening. The mullion section member is of a suitable length, has opposed channels at opposite sides each for slidably receiving the edge of the curtain of a respective roller shutter door. A portion bridges the two channels, and behind said portion on the inside face of the mullion section member, there is provided flange means defining a recess between said flange means and said portion, in which a plate-like tongue member is slidably received to slide longitudinally of the length of the mullion section member. This permits the releasable fastening thereof to a similar mullion section member fastened relative to said door opening. The tongue member has a cut-out at one side which is hidden by said flange means.