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Revised March 1987

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Contents

• Types of large round balers
• Work quality
• Baler attachments

Related publications

• G1955, Large Round Bales: Management
• G1957, Large Round Bales: Safety

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Large Round Balers

Bill Hires and Charles Ellis
Department of Agricultural Engineering

The continuing search for a labor-saving method of hay harvest led to the development of the large round baler. At this time there are 15 manufacturers selling over 40 balers that produce large round bales of 400 to 2,300 pounds in size.

Types of large round balers

Three baler types are produced:

• Ground roll
• Carried bales formed in an expandable chamber
• Carried bales formed in a fixed chamber.

Ground roll baler
At the present time there is one ground roll baler being manufactured. Following are some of its characteristics. The bale rolls on the ground on top of the incoming windrow. The upper portion of the bale is confined by a series of cables and rollers. Ground roll bales have an average density of 11 to 12 pounds per cubic foot. Tractor power takeoff (PTO) horsepower requirements are in the 30 + horsepower range for ground roll balers.

Figure 1
Ground roll baler. Lundell 760D: (A) pickup; (B) bale forming roller; (C) bale forming cables; (D) bale forming roller; (E) twine rollers; (F) second bale starter.

Expandable chamber balers
Bales formed in these balers have tension applied by either belts or chains and slats commonly called raddles. Tension is applied to the bale as the core is formed until the bale is completed. Some of the balers of this type produce a bale with a uniform density, while others produce a bale with a density at the outer diameter that is about double that at the center. Whole bale density averages from 10 to 17 pounds per cubic foot, and production averages from 6 to over 20 tons per hour. Tractor PTO horsepower requirements vary from 30 to 120 hp.

Figure 2
Expandable chamber baler.

Carried fixed chamber balers
These balers tumble hay within the bale chamber until the last stages of formation, when tension is maintained by hydraulic pressure. The baling chamber is a series of belts or rollers. The operator reads a hydraulic pressure gauge to determine when a bale is done. These bales have a low density or soft-core center and an outer diameter density about double that of the center. Whole bale density averages from 10 to over 19 pounds per cubic foot, and production capacity is about 4 to 18 tons per hour. PTO power requirements are 30 to 70 hp.

Figure 3
Carried fixed chamber baler.

Work quality

Ground roll balers
This baler produces a lower density bale with irregular surfaces. Nonuniform windrows cause poor-quality bales. Irregular and lower density bales result in severe weathering with high moisture penetration. Pickup and bale-chamber losses are impossible to measure because hay is rolled on the ground, and all losses appear on the ground behind the pickup.

Carried expandable chamber balers
Good bales are easier to make when windrows are large and uniform. Occasionally, the bale core is hard to start and might even need to be discharged and a new bale started. Bale formation is usually easier if an extended weave pattern is followed while baling. Some balers now weave automatically allowing the tractor to drive straight and produce a uniform bale. These balers can be used to produce bales varying in weight. Bales tend to be uniform in shape and density. Under most conditions, you back up the baler before discharging the bale. You must take care in lowering the rear gate or door, as expensive damage can occur if the gate strikes the unloaded bale as it closes. Driving forward before closing the gate prevents this. Some balers have an optional attachment that will cause the bale to move away from the rear gate. Twine consumption varies with bale size and number of wraps. From 150 to 450 feet per ton are needed, as compared to small square bales that need 670 feet per ton.

Carried fixed chamber balers
Windrow size and shape is not as critical for these balers, and an extended weave is not needed when starting the bale because the hay tumbles loosely in the chamber. When the outer part of the bale is being formed, an extended weave driving pattern will be needed on irregular or light windrows, because as the hay is under tension and will not move across the chamber. For ideal bales, use the maximum bale chamber capacity.

Baler attachments

Attachments available depend on the particular manufacturer. Horns or lights can be mounted on the tractor to signal when the bale is done. Some manufacturers offer bale sensing instruments that warn of an improperly shaped bale.

Manual, electric or hydraulic twine feeding mechanisms may be used. Automatic and dual twine feed mechanisms are also available. They speed up tying and make faster baling possible.

Tedder devices are being used to fluff wide wind-rows mashed down by tractor tires or to bring wide windrows to the same width as the baler pickup. Bale ejectors can move the bale away from the tailgate. Bale counters are standard equipment in most cases.

Two attachments available on some machines or from outside manufacturers are wrapping equipment for applying plastic completely around the bale and hay preservative equipment for metering chemical preservatives into the bale as it is formed.

Ground roll balers

Carried fixed chamber balers

Carried fixed chamber balers

*Does not apply

Carried expandable chamber balers

*Does not apply

Carried expandable chamber balers

*Does not apply

Carried expandable chamber balers

Carried expandable chamber balers

G1250, revised March 1987