Patent ID: 7633253

Claim:
An aperture closure member control arrangement, comprising: (i) pulse means operable to create a train of pulses as the closure member moves; (ii) counter means operable to count pulses of the train; and (iii) control means operable in response to the pulse count to provide an output for modifying the manner in which the closure member is driven; wherein the control means determines: (i) a fully closed count corresponding with the fully closed position of the closure member; (ii) at least one speed change count, there being a nearest speed change count which is nearer to the fully closed count than any other speed change count is to the fully closed count; and (iii) a reversing count; and wherein the control means, in use, causes: (i) the speed of the closure member to change as the closure member passes the speed change count in at least one direction; and (ii) the response to an obstruction to change as the closure member passes the reversing count in at least one direction, and wherein the reversing count is between the fully closed count and said nearest speed change count.