How's and Why's of Picking Heads

     Trunk shaker heads feature the best quality picking of cordon trained grapes. Imagine picking first quality grape berries, leaving most of the rot, raisins, and second crop behind! You still can pick everything if you want to, but as grape quantities increase, quality will become more important!


    The principle is acceleration and instant deceleration of mass. Have you ever gone fly fishing, snapped your leader too hard and returned with a leader tip with no fly? In other words:

    The grape trunk shaker head moves the vine with berries to the right perpendicular to the vine row, and while the berries are moving right, the head reverses direction, moving the trellis to the left. This is accomplished be a pair of horizontal picking rails moving along the trellis. The picking rails address the trunk and grape stakes below the cordon height level, so as not to damage cordon and spurs or canes. The action the berries receive is similar to cracking the whip.

    You can adjust the frequency of the shake by raising or lowering the picking head RPM. You can adjust the stroke by changing the rotational weights enclosed in the picking head. All adjustments are easily made.

The Aim/ Force Balance Shaker head hangs in the grape harvester like a pendulum. The head is free to float and follow the grapevine row automatically centering on the row. The picking rails are connected to the picking head at two points, one independent front attachment and one rear attachment on each rail, on each side of the vine row. The trunk shaker requires less than one pound of force, while running, to center the head on the vine row.

     The grape berries as they ripen, gain in specific gravity, or weight. Ripe berries are removed easily with low snapping action. Raisins, rot and second crop berries are lighter in weight, through dehydration or lack of ripening (sugar) and won't shake off, unless you desire to increase the shaking action.

      Hand picking of the grape berries results in a harvest of whole bunches. The field worker has to choose to pick the whole bunch or leave it hanging. If the field worker picks the bunch , he gets everything: good berries, rot, raisins, second crop (unripe berries) etc. If he refrains from picking the bunch he get nothing.

      Machine harvesting of grape berries results in individual loose berries. The trunk shaker harvests grape loads that are higher in sugar compared to the identical hand harvest, contains the best of the berries and has a lower MOG (Material Other Than Grapes; leaves rot etc.). Machine harvesting with a trunk type shark er head doesn't fracture the canes nor defoliate the leafing zones like a pivotal striker or bow rod shaking head. Trunk shaker picking heads do exactly as their name implies.

    Pivotal striker and bow rod picking heads are canopy or foliage shark ers. Whenever you pass a shaking devise through the foliage or canopy, you will remove and fragment some leaf particles. Canes are also broken more often. You see vineyard defoliation within 10-15 days following harvesting. Much of the defoliation occurs from broken leaves and the leaf being coated with crushed grape juice. Canopy Shakers were designed for cane pruned or young vineyards.

    Please note: Developing new vineyards are flexible and really emulate cane pruned vineyards. Trunk shakers do not work well in  these young vineyards and or cane pruned vineyards. On the other hand as the vineyards matures and becomes more rigid,the energy of the trunk shaker readily transmits to the vine. The mature vineyard becoming more rigid will break and defoliate easier using the pivotal striker or bow rod head.

    By using the trunk shaker head the grapevines aren't defoliated, they have time to recover from the growing season and harvest; storing carbohydrates prior to going dormant. The grapevines which have stored carbohydrates have more energy the following spring at bud break.

    Using bow rod and pivotal striker heads verses the trunk shaker on spur pruned vineyards, will show a decrease vineyard vigor and yields over time.

    For those growers with cane pruned vineyards, AIM does offer complete pivotal striker and bow rod heads in our GH9000 or for retrofit into existing machines.

    However, we feature the Aim/ Force Balance shaker head in our GH9000 or as a retrofit into your harvester if it will accommodate it.

    We also offer the AIM "Soft Touch"; a hydraulically controlled system that automatically adjusts the picking rail spacing and applied forces to the vine/stake diameter allowing large and small vines in the same row the same applied force.