Apparatus for monitoring sewer cleaning tool extension

摘要

A mobile sewer cleaning machine comprises an elongated sewer cleaning tool wound upon a reel mounted in a reel compartment of the machine. A reel control motor is coupled to the reel to rotate the reel in one direction to play out the tool into a sewer by unwinding it, and in the opposite direction to retract the tool from the sewer by rewinding it. A rotatably mounted tool sensing drum is frictionally engaged with and rotated by the tool and includes a position indicator adjustably mounted to its side. Two proximity sensors are positioned to sense the position indicator as the drum is rotated by extension or retraction of the tool. To provide improved accuracy and ease of operation, the two proximity sensors are mounted opposite to one another across a diameter of the tool sensing drum. First and second switches are coupled to the reel control motor for activating one of the proximity sensors upon rotation of the motor in one direction and the other of the proximity sensors upon rotation of the motor means in the opposite direction. An electronic counter is connected to the sensors by the first and second switches for counting signals generated by the sensors and displaying a count representative of the extent of the tool which extends from the reel. The electronic counter includes input switches for entering a desired count and output contacts for indicating when an entered count has been reached. An audible and/or visual alarm is activated by the output contacts of the electronic counter upon reaching the desired count.