| 摘要 |
Food-drying devices are driven with different workloads, which may require different initiation speeds, usually at lower speed for high workloads for the ease of start of rotation, and higher speed for low workloads for speedier drying. There is known food-drying device in which the drive mechanism is able to provide different handle rotation speeds limited by different gear ratios when he handle is rotated in different directions, which in fact limit the maximum speed of rotation. This is inconvenient as the user has to remember which direction is the correct one for the desired gear ratio. In this invention, a cleverer drive mechanism that can provide different gear ratios for driving automatically has been provided. The automatic gear-shift drive mechanism (200) in the invention includes a first gear system having a first gear ratio, and a second gear system having a second gear ratio, wherein the first gear ratio is higher than the second gear ratio. The automatic gear-shift drive mechanism (200) is biased to spin the drying assembly with the first gear system when the automatic gear-shift drive mechanism(200) is driven and the workload is below a threshold workload, and switch to spin the drying assembly with the first and the second gear systems when the automatic gear-shift drive mechanism(200) is driven and the workload is at or above the threshold workload. |
