| 摘要 |
<p>The up-and-over garage door is hung in the door frame, and counterbalanced by two ballast weights looped over the drive pulleys. The pulleys are each connected to drive shafts which meet in a drive unit (14) over the door. The electric motor shaft operates the drive shafts via meshing cylinder gears (28,24), with the output gear loosely fitted on the drive shaft. The output gear drives a gear (19) which is rigidly fitted to the drive shaft, and this gear meshes with the short gear rack (36) fitted to the top edge of the door. The coupling between the output gear and the driven gear is via dog teeth between the ends of the gears and with the axial pressure between the gears provided by an elastic element. This provides a limited torque coupling.</p> |
