District Level Governance in Papua New Guinea : Preliminary Report of a Pilot Study

The invention relates to a power door opener, such as the type of opener used for opening overhead garage doors includes a worm gear rod having a major thread and a carrier member coupled to the door and releasably engageable with the major thread for moving the door between open and closed positions as the rod rotates. A second thread whose pitch is smaller than the major thread is formed on the rod and on a portion thereof located between a pair of spaced apart limit switches. A control member threadably engages the second thread for movement between the limit switches as the rod rotates for terminating motor operation as the door moves into its open and closed positions. The carrier member is mounted for radial movement into and out of engagement with the major thread to permit manual operation of the door.