Systems and methods for sensor controlled reach carriage

In a reach carriage having a carriage frame and a pantographic extension arm attached to the carriage frame and driven by a hydraulic ram cylinder attached to the carriage frame, the extension arm, and a hydraulic pump, a velocity control device for the extension arm, the velocity control device comprising:

• a sensing apparatus comprising:
• a sensor attached to a clevis on the carriage frame, the sensor having a range and generating a position signal when the sensor is activated;
• and
• a marker that activates the sensor when the marker is in the range of the sensor, the marker being attached to a tang of the hydraulic ram cylinder, the tang cooperating with the clevis, and the marker rotating through an angular range, within which the sensor range is disposed, as the extension arm linearly extends and retracts;
• and
• a control unit operatively connected to the sensor and the hydraulic pump and configured to receive the position signal and to instruct the hydraulic pump to reduce or increase a flow rate to the cylinder depending on the position signal.

A method of controlling the velocity of an extension arm in a reach carriage, the method comprising:

• as the extension arm is being driven by an actuator, receiving a position signal from a sensing apparatus comprising:
• a sensor that generates the position signal;
• and
• a marker configured to move into and out of a range of the sensor as the extension arm extends and retracts;
• determining from the position signal whether the extension arm is approaching its extension or retraction limit;
• if the extension arm is approaching its extension or retraction limit, instructing the actuator to gradually reduce an actuation speed;
• and
• allowing the extension arm to be driven at full velocity if the extension arm is not approaching its extension or retraction limit.