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Feeding safety

IP.com Disclosure Number: IPCOM000250317D
Publication Date: 2017-Jun-28
Document File: 2 page(s) / 13K

Publishing Venue

The IP.com Prior Art Database

Abstract

Cut to length harvester heads use a measurement wheel to find the length of processed logs. The wheel is pressed against the trunk and follows the surface of the log. The trunk is fed through the harvester head until the target log length is reached. Concerns may arise when the measurement wheel is not working properly. If the wheel does not properly track the trunk, the target log length is never reached and feeding may continue for a long time before the situation is detected. Since the feed speeds are very large (up to 5 m/s), a harvester operator may not be able to stop the feeding process before a collision. The potential collision may be very damaging because of the large masses and speeds involved. The worst case is a stem collision with the operator cabin.

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Feeding safety

Cut to length harvester heads use a measurement wheel to find the length of processed logs. The wheel is pressed against the trunk and follows the surface of the log. The trunk is fed through the harvester head until the target log length is reached.

Concerns may arise when the measurement wheel is not working properly. If the wheel does not properly track the trunk, the target log length is never reached and feeding may continue for a long time before the situation is detected. Since the feed speeds are very large (up to 5 m/s), a harvester operator may not be able to stop the feeding process before a collision. The potential collision may be very damaging because of the large masses and speeds involved. The worst case is a stem collision with the operator cabin.

Previous efforts

The simplest solution for preventing to stem-machine collisions would be to prevent feeding towards the machine at all times. This is not feasible because it would prevent too much normal harvester usage. Certain processing methods even encourage feeding the logs under the boom.

Also, sensors for determining harvester head position and angle could be used. As long as the measured log feed length is correct, this is sufficient for preventing stem/machine collisions. This would require always to rely on the measured feed length. What is needed is an indicator for the reliability of the measured feed length.

The current method for evaluating feed length reliability works by comparing feed time (and speed) with the measured log length. If the measured log length does not increase during feeding, one may conclude that the measurement wheel is not working correctly and feeding must be stopped. This approach may not always work. Sometimes the measurement wheel may continue to partially rotate during feeding a...