| 摘要 |
A heel nailing machine has a plurality of feed tubes (14 to 24) through which nails can be fed one by one from a nail separating station (12) to a receiving block (26) for transfer by a so-called nail loader (40) to a nailing station (36). Each tube has a nail sensor (46) for optically sensing the passage of nails therealong. Each sensor (46) generates a signal in response to the passage of a nail and this signal illuminates one of an array of lights (108 to 118) to indicate the presence of a nail. In the event that no nail is present at any one location the light associated therewith is not illuminated and in addition an alarm (122, 124) is operated. For enabling the sensing means to operate in different environments compensating means (66, 67) is provided for compensating changes in sensitivity of each sensor (46). |
