| 摘要 |
The machine has a baling chamber (44) in which crop is rolled into a bale (50) which is then, whilst still rotating, wrapped with net (220) advanced from a roll thereof by a pair of feed rolls (244, 246) connected to a belt drive (332, 336, 334). An arrangement is provided to warn an operator if the roll of net (220) becomes exhausted or if the net is being drawn through the feed rolls (244, 246) when this is not wanted. An idler roll (242) is disposed upstream of the feed rolls (244, 246) and a pulse detector circuit (398) associated therewith generates a signal of zero volts on rotation of the feed rolls (244, 246) and a high output in the absence of rotation. The signal is received by two circuits (402, 404) having switches (406, 414) therein linked to the drive (332, 336, 334) causing one circuit (402) to be open and the other (404) to be made when the drive is not operational and vice versa when the drive is functioning. In the said other circuit (404) an inverting amplifier (410) is connected between the switch (414) and the signal received. The effect is that the said one circuit (402) is made and lights a warning lamp (408) when there is exhaustion of wrap material, and similarly the other circuit (404) is made and gives a warning when net is being drawn when not desired. |
