| 摘要 |
<p>A powder dispensing assembly (10) including an elongated chute (34) having opposite ends (40) pivotally supported for rotation about a pivot axis (38) within an elongated housing (20) and having a funnel-shaped cross-section with a wide upper portion (42) and a narrow lower portion. A dispensing platform (26) is integral with the rear wall (46) of the chute (34) and extends forwardly beneath the front wall (44) and slopes upwardly to a lip (28) over which particles of powder move to define a falling curtain of powder particles. A supply platform (30) is supported just above the pivot axis (38) and receives powder from an elongated slot (32) and supplies powder to the dispensing platform (26) as the powder falls downwardly through the chute (34). The supply platform (30) is wider than the angle of repose of the powder supplied thereto so that when the supply platform is not moving powder is not being supplied to the lower dispensing platform (26). An electromagnet (80) co-operates with a spring plate (66) which is, in turn, connected by a rod (58) through the housing to the rear wall (46) of the chute (34). The electromagnet (80) operates on 60 cycle AC and, when energised, sets up a magnetic field to bend the spring plate (66) to rotate the chute (34) in a counter-clockwise direction about its pivot axis (38) and between cycles the spring plate (66) springs back and returns the chute (34) by rotating it in the clockwise direction. The upper supply platform (30), therefore, rocks about the pivot axis (38) to supply powder to the lower dispensing platform (26), the supply of powder from the supply platform (30) being less than the capacity of the dispensing platform (26).</p> |
