| 摘要 |
<p>A tubular latch assembly for a door and adapted for operation by either an "opener" such as a thumbpiece on one side and/or a knob on the other. The tubular latch comprises a central latch subassembly mounted inside the door and including a latch casing seated in the door, a bolt slidably mounted in said latch casing for extension/retraction (such as through an open face plate), a pivoting retraction lever coupled to the bolt, a spindle hub having a pair of offset cam surfaces, and a pivoting reversing lever engaged at one end with the bolt and at the other end with the second cam surface on the spindle hub for driving the bolt. The central latch subassembly allows opening by either the opener (e.g., thumbpiece) or by rotation of the knob, operation of the knob not affecting the opener and vice versa. This entirely eliminates any need for off-axis motion translation or accompanying mechanisms that are ordinarily used to adapt the axis of rotation of an opener to the orthogonal axi s of rotation of a latch or spindle hub, thereby reducing the total number of parts as well as internal friction.</p> |
