Search Results
You are looking at 1 - 6 of 6 items for
- Author or Editor: Dale E. Marshall x
For 50 years, engineers, producers, processors, and manufacturers have been working on new and improved ways for mechanization of the harvest of pickling cucumbers, Cucumis sativus L. In 1957, processors investigated multiple-pick concepts. Multiple-pick harvesters were commercially manufactured in the early 1960s (Chisholm–Ryder). In the late 1950s, Stout and Ries evaluated the known multiple-pick harvesting concepts. In the early 1960s, once-over harvesting concepts were considered and evaluated by Ries and Stout. By significantly increasing the plant population and other horticultural practice and variety improvements, once-over harvest became the main thrust of mechanization from 1965 on. By 1970, at least major five commercial manufacturers sold harvesters (Blackwelder, FMC Corp., Hart Carter [later sold out to Cuke, Inc.], Porter-Way, and Wilde). In 1996 there are four commercial manufacturers (Cuke, FMC Corp., Jerry's Welding, and Pik Rite). Limited multiple-pick research and manufacturers persisted (Aero-Glide, Mac-Weld, and Powell). By 1975 over 85% of Michigan's pickling cucumbers were mechanically harvested, leading all other states. Today, about 60% of Michigan's production is harvested with machines. The information presented will be informative and an historical aid for engineers, manufacturers, horticulturists, processors, and historians, etc. to ensure that the worldwide research is known by scientists endeavoring to accomplish harvest mechanization.
The handling of mechanically harvested vegetables typically results in significant impact damage (bruises, broken or splits) when falling 1.8 to 2.8 m into empty field transport vehicles. To reduce this damage, reinforced vinyl hammock designs were suspended 0.7 m above the bottom of the container on rubber elastic springs. As the vegetables filled the hammock it settled to the floor. The hammock and spring system provided cushioning and significant damage reduction compared to when vegetables directly impacted the bare floor. Field studies with the hammock showed a 65 to 80% damage reduction to the first 15 to 20 cm depth of carrots and onions and 50% reduction in pickling cucumbers and potatoes. Compared to active systems such as an air bag, passive decelerators are simple, relatively inexpensive and significantly reduce impact damage. The cost effectiveness depends on the number of fills per season. Typical frequency of use of high-lifts in carrots (30 to 35 times/day) will pay for the hammock system in 1 season. To maintain field quality for the consumer, the impact damage encountered in field harvesting and handling operations can and must be reduced.
For over 86 years producers, processors, engineers, and equipment manufacturers have attempted to mechanize the harvest of asparagus. Over 60 U.S. patents have been issued. Probably the most sophisticated harvester tested was started in 1987 by Edgells Birdseye, Cowra, Australia. After successful field tests of the 3-row, selective (fiber optic), harvester for flat-bed green asparagus used in canning, 3 more were built at a cost of $US 4.5 million, and harvested 500 acres until 1991 when the company ceased canning. Recovery was 30 to 80% with 50% being typical. Wollogong University in Australia is now researching a selective (fiber optic), harvester for flat-bed green asparagus. It utilizes multiple side-by-side 3 in. wide by 24 in. dia. rubber gripper discs which rotate at ground speed. No harvester prototype has been commercially acceptable to the asparagus industry due to poor selectivity, low overall recovery (low yield relative to hand harvest), mechanical damage to spears, low field capacity per harvester, or overall harvesting costs that exceed those for hand harvesting. The reality may be that asparagus production will cease in the traditional geographical areas where growing costs and labor costs are high, although niche fresh markets may help some growers survive.
The tender skin of bell peppers (Capsicum annuum L.) covers a crisp, fragile flesh that is easily bruised, cracked or crushed. During commercial harvest and postharvest handling operations, bell peppers undergo several transfers, each of which has the potential for causing mechanical injury to the peppers. These mechanical injuries include abrasions, cuts, punctures, and bruises, which affect the market grade and reduce pepper quality and subsequent life. Previous research on handling fresh vegetables and fruits has shown that the instrumented sphere (IS) is a tool that can help identify potentially damaging impacts during harvest and postharvest handling operations. For the study reported, the IS was used to evaluate the damage potential for peppers being hand harvested, and for peppers on a packing line. Studies in the field attempted to duplicate how pickers harvest peppers into pails and then empty them into empty wooden pallet bins. For the packing line evaluated, the diverging roll-sizer had the greatest potential for damage. Adding cushioning to hard surfaces and removing the metal support from under the cross-conveyor would help to reduce pepper damage. Cushioned ramps, and hanging flaps or curtains should be used to help reduce acceleration and drop height between pieces of equipment. All locations should be cushioned where peppers impact a hard surface, and drop height should be limited to 3 inches (8 cm) on a hard surface and 8 inches (20 cm) on a cushioned surface. The speed of all components in the system should be checked and adjusted to achieve full line flow of peppers without causing bruising. Workers must receive instruction on the significance of bruising during the harvest and postharvest operations.
Green bell pepper is a popular vegetable in the United States. Michigan is the 5th-leading production area, producing 480,000 cwt of green bell peppers in 1994. The tender skin of the green bell pepper covers a crisp, fragile flesh that is easily bruised, cracked, or crushed. During commercial harvest and postharvest handling operations, bell peppers undergo several transfers, each of which has the potential for causing mechanical injury to the pepper fruit. These mechanical injuries include abrasions, cuts, punctures, and bruises. Mechanical injuries and bruises are defects that affect the market grade of the peppers, and may reduce pepper quality and subsequent shipping life. The impacts occurring in a pepper field and on a Michigan packing line were measured using an Instrumented Sphere. Field tests attempted to duplicate how pickers harvest bell peppers into 5-gal pails and empty them into empty wooden tote boxes. Other tests were on an entire packing line. Most bruising on packing lines occurred at the transfers between different pieces of equipment when the peppers fell or were propelled from conveyors onto uncushioned metal plates or rollers. Several transfer points were identified as areas where much of the mechanical damage occurred and improvements were suggested to the packer. Bell peppers were found to bruise on their shoulders; therefore, shoulder bruises may be used as an indicator of injury. The major problems with packing lines were excessive height differences between line components, lack of control of rolling velocity, and lack of cushioning on hard surfaces.