Needle with air duct
A baler has a bale chamber and a needle movable through the bale chamber to pass a strand of twine from one side of the bale chamber to a knotter located on the opposite side, the twine being engaged by a tip of the needle. In the invention, pressurized air is directed at the needle tip. The supply of pressurized air may be discontinuous and timed to coincide only with certain phases of the needle operating cycle. The air stream avoids crop material being caught up in the knots formed by the knotter.
1. A baler comprising:
a bale chamber; and
a needle assembly having a needle movable through the bale chamber to pass a strand of twine from one side of the bale chamber to a knotter located on the opposite side, the twine being engaged by a tip of the needle, and a passage connected to a supply of pressurized air, wherein means are provided on the needle for directing a pressurized air stream from the passage connected to a supply of pressurized air towards the tip of the needle.
2. The baler of claim 1 , wherein the supply of pressurized air is discontinuous and timed to coincide only with certain phases of a needle operating cycle.
3. The baler of claim 2 , wherein the pressurized air is timed to occur during the passage of the needle through the bale chamber towards the knotter, to dislodge crop material from the path of the needle.
4. The baler of claim 2 , wherein the pressurized air is timed to occur when the tip of the needle is adjacent the knotter, the air stream configured to keep the knotter free of crop material.
5. The baler of claim 2 , wherein the pressurized air is timed to occur during the return movement of the needle through the bale chamber away from the knotter to maintain the tip of the needle free of crop material.
6. The baler of claim 2 , wherein a valve for controlling the supply of pressurized air is connected to or incorporated within an axle about which the needle pivots.
7. The baler of claim 2 , wherein a conduit along which the pressurized air flows towards the tip of the needle is formed as an integral part of the needle.
8. The baler of claim 6 , wherein the needle is commonly connected to a yoke shaft extending between and carried by two pivotably mounted arms, and wherein the yoke is hollow and serves as a buffer of compressed air.
9. The baler of claim 8 , wherein air from the yoke is guided into a channel in each needle which directs a pressurized air stream towards the tip of the needle.
10. The baler of claim 8 , wherein compressed air is guided into the yoke through a pivot of at least one of the arms carrying the yoke.