Study, design and development of a low-budget prototype harvesting machine for Roman Chamomile.

Roman Chamomile is used for the production of essential oils, as an aroma in tea and is popular in aromatherapy. In Belgium and The Netherlands the flowers are grown in beds and the fields are rather small and irregularly shaped. Existing large self-propelled flower harvesters are not designed for these typical conditions. Manually harvesting these flowers, as is most common in our regions, is time-consuming, laborious and ergonomically unjustified. The objective was to develop a prototype of harvester capable of harvesting the flowers mechanically, taking into account the small-scale application, and that delivers a harvest quality that is equal to manually harvested flowers. The working principle of a combine harvester was adapted to include two eccentric wheels with different diameters. These are connected with each other by means of a crank and a connecting rod. Based on this principle two drums were built with specially designed combs and knifes mounted on the outside drum. The flowers, cut by the comb-knife combination, were removed from the combs with a rotating brush and collected in receptacles on the conveyor belt. The new harvester is currently subjected to a series of tests. Hitherto, one preliminary test was done and delivered promising results. Further testing and evaluation is planned in the next growing season. Introduction Roman Chamomile or Garden Dog Fennel (Chaemoemelum nobile) (Fig. 1) is used for the production of essential oils, as an aroma in tea and is popular in aromatherapy, whose practitioners believe it to be a relaxing agent to combat stress and promote sleep. In Belgium and The Netherlands the flowers are grown in beds and the fields are rather small and irregularly shaped. Existing flower harvesters (Figs 2 & 3) are not designed for these typical conditions. These large self-propelled machines have a working width of 4 m and a capacity of 0.3 ha/h. Manually harvesting these flowers, as is most common in our regions, is timeconsuming, laborious and ergonomically unjustified. The objective of this study was to develop a prototype of harvester capable of harvesting the flowers of Roman Chamomile mechanically, taking into account the small-scale application, and that delivers a harvest quality that is equal to manually harvested flowers. The stalks of the harvested flowers cannot exceed 0.02 m. The entire flower must be harvested and is collected in receptacles and the remaining plant should not be damaged since several harvests a year take place. Materials and methods In a first phase, based on other harvesting techniques, a first test set-up (Fig. 4) was developed. Most harvesting techniques use a comb to grasp the flowers. With the threedimensional CAD program ‘Solid Works’ a comb (Fig. 5) was designed from an Lprofile of 4 mm thick in which teeth were milled. The teeth were 7 mm long and are placed at 13 mm intervals, leaving 5 mm of free space between the teeth. The top of the teeth are bevelled to guide the stalks into the free space between the teeth. ster Fig. 3 Slovak VZR-4 Fig. 1 Roman Chamomile Fig. 2 Chamomile harve To cut the stalks of the flowers two small Stanley knives were mounted on the comb. Figure 4 shows the comb attached to a rotating arm. The combs pivot around the arm by turning the handle and describe a circumference with an adjustable radius. The angle of the comb in respect to the described cylindrical path was adjustable. Since chamomile was not available at the time of testing, the tests were carried out with daisies, which are comparable with chamomile. The set-up was also tested for cutting red and yellow chrysanthemums. In a second phase a prototype of harvester was developed. The working principle of a combine harvester was adapted to include two eccentric wheels with different diameters (Fig.6). These are connected with each other by means of a crank and a connecting rod. The eccentricity of the cogs makes that the crank-rod combination is at one moment in a stretched position whereas at another moment it is in a bent position. This continuously changes the angle of the crank with the cogs. The movement of the crank is passed onto the comb. Important is that both cogs turn at identical speeds. The position of the comb can be varied by giving the smaller cog a different position vis-a-vis the larger cog. In the above figure the centre of the smaller cog is situated to the right of that of the larger cog. By placing the centre of the smaller cog beneath, above or left to that of the larger cog it is possible to position the comb differently for grasping the plant. Based on this principle two drums were designed as shown in Figure 7. The specially designed combs with knife are mounted on the outside drum. Fig. 6 Working principle of the prototype comb rotating arm