Group Title: Citrus Station mimeo report - Florida Citrus Experiment Station ; CES 66-7
Title: Experimental harvest systems for citrus
Full Citation
Permanent Link:
 Material Information
Title: Experimental harvest systems for citrus
Series Title: Citrus Station mimeo report
Physical Description: 2 leaves : ; 28 cm.
Language: English
Creator: Coppock, Glenn Edgar, 1924-
Hedden, Scott L
Citrus Experiment Station (Lake Alfred, Fla.)
Florida Citrus Commission
Publisher: Citrus Experiment Station :
Florida Citrus Commission
Place of Publication: Lake Alfred FL
Publication Date: 1965
Subject: Citrus -- Harvesting -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: G.E. Coppock, S.L. Hedden.
General Note: Caption title.
General Note: "400-10/12/65-GEC."
 Record Information
Bibliographic ID: UF00072439
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 76757032

Full Text

Florida Citrus Commission and
Citrus Experiment Station CES 66-7
Lake Alfred, Florida. 400-10/12/65-GEC

Experimental Harvest Systems for Citrus

G. E. Coppock
Florida Citrus Commission

S. L. Hedden
USDA, Agricultural Engineering Research Division

Interest in mechanizing citrus fruit harvesting is at an all-time high. It
has been largely stimulated by the high cost of hand harvesting and by an antici-
pated labor shortage. Private manufacturers and individuals as well as public
research agencies are giving the problem considerable attention.

Harvesting is a vital part of the citrus industry. Under present practices,
it is controlled by the utilization section of the industry. The nature of
citrus fruit is such that it can be left on the trees for a considerable period
of time after it is considered mature. This period allows the harvesting to be
controlled generally by market conditions and other utilization demands. This is
a distinct advantage which most other fruit industries do not enjoy. But, when
harvesting is viewed as the possible controller of utilization, which could be
the case in the event of a severe labor shortage, its importance takes on a new

The Florida Citrus Experiment Station, in cooperation with the Florida
Citrus Commission and the U. S. Department of Agriculture is studying two ex-
perimental harvesting systems: a mass removal system for cannery fruit and a
picker's aid system for fresh fruit. In the mass removal system, the fruit is
shaken off the tree and then caught on a padded catching frame. A mechanical
inertia-type tree shaker and a high velocity-oscillating air blast are being
studied as a means for shaking the tree.

A complete harvesting system using the inertia-type tree shaker has been
built to further test the system under regular grove conditions. It consists
of two tractor-drawn catching frames, each equipped with a tree shaker. One
frame has a conveying system to convey the collected fruit from under the tree
into baskets positioned to the rear of the frame. The other frame serves only
to support the tree shaker and to roll the fruit across a row-seal into the
conveying system on the first frame. The surface of both catching frames is
sloped 20 degrees so that the fruit drains easily toward the cross conveyor. In
operation, the machines are pulled into position on opposite sides of the tree
and the frames are extended until they form a seal around the tree. The shakers
are attached to the tree from opposite sides and operated at a frequency of
from 0 to 400 cycles per minute.

The performance of this system looks very promising for harvesting early
and midseason oranges and grapefruit for cannery utilization. Its most promis-
ing performance has been in high yielding groves on fairly level terrain. A
removal efficiency of above 85 percent has been obtained at a harvest rate of
12 trees per hour. When harvesting yields 8 boxes per tree, 4 men on the
machine can do the work of 10 regular pickers. No doubt, this manpower advantage
can be increased by pruning the trees to reduce the number of main limbs to be

shaken and by using a chemical to loosen the fruit, thus reducing the time re-
quired to shake the fruit off. Although the effect of the shaking action on
tree vigor and on subsequent yields has not been completely evaluated, the first
year's results indicate that this may not be a serious problem in early and mid-
season fruit. Harvesting 'Valencia' oranges presents a particular problem because
there are two crops of fruit on the trees at harvest time (large mature fruit and
small immature fruit) and the tree shaker does not distinguish between them.
Selective shaking has met with some success but usually with a corresponding re-
duction in removal efficiency.

The oscillating air blast offers a means of shaking the tree to remove its
fruit in a continuous manner as compared to the stop-and-go pattern necessary
with the mechanical tree shaker. This continuous operating characteristic of
the air-blast concept makes it potentially a high volume harvest system.

An experimental air-blast machine has been built to evaluate this means of
fruit removal. It is constructed to discharge air from an axial flow fan
through a rectangular outlet one foot wide at velocities up to 115 mph. This
sheet of oscillating air is directed at the tree as the machine is moved down
each tree row. A "lift and snap" response is obtained by the use of "oscillating
vane" air delectors located within the discharge air stream. Considerable ob-
jectionable shredding of the leaves occurred especially at the higher air
velocities (above 100 mph). This leaf damage and the problems associated with
the development of a tree-seal for a continuous moving catching frame are the
main problems hindering the development of this harvesting system.

The picker's aid system is intended for harvesting fruit destined for the
fresh fruit market. In this system, careful handling of the fruit is of prime
importance. The system consists of placing a group of picker's on a mobile
platform equipped with a fruit handling system. The pickers pick fruit in the
conventional manner and empty the picked fruit into the fruit handling system
which automatically delivers it into suitable containers on the ground. Pruning
the trees into narrow hedgerows simplifies the platform's construction require-
ments thus keeping the per man fixed cost to a minimum. Several plots of trees
have been pruned to a narrow hedgerow shape and an experimental platform is under
construction to evaluate this harvest system. Many of the new groves are being
planted with the trees spaced close in one direction. These groves could be
easily shaped, as the trees grow, to fit into a picker's platform harvest system.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 400-10/12/65 GEC

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