Seeding Machinery For Small Grains
from issue: 25-4
Seeding Machinery For Small Grains
This is reprinted from Farm Machinery and Equipment by Harris Pearson Smith, an agricultural engineering textbook copyrighted 1937.
The most satisfactory method of sowing any of the small grains is with the grain drill. The largest yields are obtained from fields where the seed have been deposited evenly and in the right amount in a firm, compact soil and covered at a uniform depth. It is practically impossible to secure these conditions when the seed are sown with a broadcast seeder.
In general, grain drills may be classed as horse-drawn and tractor-drawn drills. Horsedrawn drills are divided into the regular field drill and the one-horse drill. The field drill may be referred to in accordance with the type of furrow opener and seed box used on the drill.
Frame.- The frame is usually made of angle steel, well braced and reinforced at the corners (Fig. 271). It is necessary that the frame be strong enough to prevent sagging and to hold parts in alignment, as all parts are connected to the frame. The axle is carried beneath, with the wheels on each end of it. The seed box is carried above, while the furrow openers are suspended below. Roller bearings are usually used on each end of the angle. (Fig. 272).
Wheels.- The wheels found on grain drills may be made of wood or steel. Some planters prefer one and some the other. For some parts of the country wooden wheels are preferred but they have the disadvantage of wearing out quickly; on the other hand, they do not slip so easily on hillsides and do not pick up loose dirt and soil and drop it on the exposed gears. Most drills sold in the Southwest are equipped with steel wheels because of the climatic conditions which affect wooden wheels. Figure 273 shows a grain drill equipped with rubber tires.
In the hubs of the wheels are ratchets and pawls to afford a means of transmitting the power from the hub of the wheel to the axle and, at the same time, allow turning where it is necessary that one wheel remain stationary and the other turn. It is essential that the pawls engage the ratchet immediately after the grain drill is moved forward. If the wheels can be revolved any distance without the pawls engaging immediately, bare strips will be left in the field.
Seed Box.- The seed box should be well braced and built rigid. The end of the box is shaped somewhat similar to a trapezoid (Fig. 274). The box tapers from the top, allowing the seed to flow directly into the feed cup. When the box has a partition running lengthwise through it, the front section for grain and the rear section for fertilizer, it is termed a fertilizer drill. Otherwise, it is a plain drill. Agitators are provided to prevent the grain bridging over in the box. They may be single or double rods. Figure 275 shows a double-rod agitator. The grain feeds are in the bottom of the box. There are two types of grain feeds: the fluted-wheel and the internal double-run force feed.
The Fluted-wheel Feed.- The fluted-wheel feed is considered the simpler of the two feeds. It is also more generally used. It consists mainly of a fluted-wheel feed roll, feed cutoff, and an adjustable gate. Figure 276 shows that the feed roll and the cut-off are mounted on a square shaft running through the feed cups. The feed roll turns with the shaft, forcing the grain out over the gate where it falls into the seed tube. The gate is adjustable for different size seeds.
Power is transmitted from the main axle to the feed shaft by gears or sprockets and chains.
The quantity of seed sown per acre is varied by exposing more or less of the feed roll to the seed inside of the feed cup and by adjusting the gate. Figure 277 shows a typical indicator plate used to adjust the fluted feed roll to sow the desired quantity per acre. The various adjustments of the fluted wheel are shown in Fig. 276.
The Internal Double-run Force Feed.- This feed shown in Fig. 278 gets its name from its construction. It consists of a double-faced wheel having a small and a large side. The small side is used for planting small seeds while the large side is used for planting larger seeds such as oats, wheat, peas, and beans. Figure 278 shows one side covered while the other is in use. The lid is hinged over the middle of the wheel so it can be reversed to cover either side.
The quantity of seed sown per acre is varied by varying the speed of the feed wheels. Figure 279 shows an arrangement for changing the speed. Special attachments to reduce the size of the outlets and adjustable gates also aid in regulating the quantity of seed sown per acre.
Seed Tubes.- Seed tubes are provided to conduct the seed from the feed cup down through the boot and furrow opener into the furrow.
The most common type of seed tube is the steel ribbon shown in Fig. 280. Being rolled with the lower edge slightly thinner than the upper edge makes the tube collapsible to half its normal length without diminishing the inside diameter or retarding the even flow of grain through it.
Other kinds of seed tubes are the steel wire, the rubber, and the telescope.
Figure 280 shows how the grass-seed tube is attached to the regular seed tube.
When fertilizer is distributed it may also pass down the regular grain-seed tube.
Boot.- The boot is the hollow casting into which the lower end of the seed tube extends and to which the furrow openers are attached (Fig. 288).
Furrow Openers.- There are four types of furrow openers used on grain drills; the hoe, shoe, single, and double disk.
The hoe furrow opener shown in Fig. 281 consists of a single- or double-pointed shovel fastened to the lower part of the boot. The grain drops into the furrow directly back of the shovel. A spring or pin trip is provided so that when a hoe strikes an obstruction, no damage is done. This type of opener often gives trouble by clogging up when used in trashy ground.
The shoe furrow opener (Fig. 282) is made from two flat pieces of steel welded together to make a cutting edge similar to the curved-runner opener used on corn planters.
Single-disk furrow openers consist of one disk slightly dished and securely fastened to the boot and set to run at a slight angle (Fig. 283). The seeds are dropped from the boot on the convex side of the disk at a point below and to the rear of the center. A toe scraper is used on the convex side and a tee scraper on the concave side to keep the disk clean.
The single-disk opener gives good penetration, cuts trash well, and does not easily clog. Half of the openers are assembled with the concave side facing the right and half to the left. Penetration is aided by spring pressure. They may also be set staggered or in a straight line.
Since the disks revolve, they must be provided with bearings that are well designed, constructed, and lubricated. Figure 284 shows a cross-section of the various parts of a well-designed disk bearing.
Figure 283 shows the correct and wrong way to set single-disk furrow openers.
A double-disk opener is composed of two disks, having very little dish, set facing each other at a slight angle so as to form a bevel-cutting edge where they penetrate the soil. In this position the disks open a clean furrow and leave a small ridge in the center so that, when the seed are deposited in the furrow, there is a tendency to make two distinct rows about 1 inch apart. A cutaway view of a double-disk furrow opener is shown in Figure 285. The seed are protected while passing between the disks until they reach the bottom of the furrow.
Lister or deep-furrow openers are shown in Figs. 286 and 287.
Covering Devices.- The most common type of covering device is the drag chain. Figure 288 shows how it is hooked to the boot and how it drags over the furrows to cover the seed without packing the soil.
In the sub-humid regions where the soil is dry and where the soil is liable to blow, press wheels are used to cover the seed and press the soil around them. Figure 289 shows a drill equipped with large press wheels. The regular wheels are replaced by the press wheels. The latter also drive the seeding mechanism. Small gang press wheels (Fig. 290) also may be obtained.
Size of Drill.- The size of a grain drill is determined by the number of furrow openers and the distance they are spaced apart. The size is expressed as 18 by 7 which means there are 18 furrow openers spaced 7 inches apart. Drills can be secured with the feeds and furrow openers spaced either 6, 7, or 8 inches apart.
Land Measures.- Grain drills are all equipped with a small device, similar to the one shown in Fig. 291, which is called a land measure or a surveyor. This is an instrument which is so designed that it determines the number of acres sown. If the operator will keep a record of the number of bushels placed in the seed box and the number of acres sown, a check can be made as to the accuracy of the drill in the amount of seed being sown per acre. This is not termed calibration.
Calibration of Grain Drills.- Many grain drills do not sow accurately, even though the indicator on the dial plate is set correctly. Some will sow more seed than the dial indicates, while others will sow less.
Oftentimes the operator will attempt to check the drill in the field by measuring off a certain acreage, seeding it, and, then, determining the amount of seed sown. At best, this is a very poor method of checking a drill.
The method of calibrating a drill is as follows: First, find the width of the strip the drill will sow. Measure the distance between furrow openers and multiply it by the number on the drill. Next, find the length of the strip of that width necessary to make 1 acre. This is done by dividing 43,560 – the number of square feet in 1 acre – by the width of the strip sown by the drill. The result will be the distance the drill must travel to sow 1 acre of grain.
Now, find the number of times the wheels on the drill will turn in going this distance by dividing the distance to be traveled by the circumference of the wheel.
Fill the seed box with grain.
Set indicator on the scale to sow whatever quantity of seed is desired.
Jack up the drill and place a paper bag under each seed tube. Tie a rag around each tire so each revolution of each wheel can be counted.
Engage the clutch and turn the wheels, counting each revolution. Turn them about the same speed they would travel in the field. When the wheels have been turned the equivalent of 1/4 or ½ acre, the grain is collected and weighed. The weight of grain sown by each feed should be recorded separately so each feed cut can be checked. The amount is multiplied by 4 if 1/4 acre was selected, and by 2 if ½ acre was sown to figure on an acre basis.
If what is used and the indicator is set to sow 8 pecks, 8 pecks should have also been collected. If only 6 pecks of grain are collected the drill is in error.
The percentage of error of the indicated quantity is calculated by dividing the difference between the quantity collected and the quantity the indicator was set on by the indicated quantity.
Furrow-opener Lifts.- The furrow openers are lifted either by hand levers or by power-lifting devices. If by hand, there is one lever provided for each half of the furrow openers. When the drill is large and drawn by a tractor, power lifts (Fig. 292) similar to those used on plows make it possible for the tractor operator to raise and lower the furrow openers by simply pulling a rope to engage the clutch.
Tractor Hitches.- Where the ground is level and the acreage to be seeded is large, several grain drills may be arranged in such a manner that they all can be hitched to one tractor. One drill is usually hitched directly behind the tractor; then, with a special designed hitch, shown in Fig. 293, other drills are hitched to each side. As many as five large drills may be hitched to the same tractor.
Grass-seed Attachment.- A grass-seeding attachment can be secured for all grain drills. When used, it is attached in front of the main seed box, as shown in Fig. 280. The fluted-wheel-type of feed is used in the feed cups. The seed tubes either empty directly into the regular grain-seed tube or they may be clamped to the side and let the grass seed fall behind the furrows openers.
Fertilizer Attachments.- When a fertilizer attachment is used the drill is usually known as a fertilizer drill, even though it is equipped with the regular grain-sowing feeds. Figure 295 shows a cross-section of a fertilizer drill. The feed for distributing the fertilizer is shown in detail in fig. 296. The regular grain-seed tube serves as spout to conduct the fertilizer down to the soil and prevents the wind blowing part of it away.
One-horse Drill.- It is often desirable to sow some of the small grains, peas, or soybeans between the rows of growing crops at the last cultivation. A special type of drill for doing such work has been made in the form of the one-horse five-hole drill shown in Fig. 298. It is a rather short narrow machine having a seed box, steel wheels, and furrow openers on the same principle as that of the regular type. The weight of the machine is carried on a large wheel in front and two small ones behind. The large wheel in front acts as a drive wheel transmitting power to the grain feeds by means of a chain and sprocket. Handles are provided for the operator to guide the machine. Grass-seed and fertilizer attachments may be secured on these machines.
Alfalfa Drill.- Alfalfa and grass seed are sown in rows closer together than the average grain drill will sow them. A special drill having furrow openers 4 inches apart is now being made. This makes an excellent drill for sowing alfalfa, clover, red top, timothy, blue grass, rape, sudan grass, millet, flax, and hemp. These different seeds can be planted in a large variety of quantities to the acre. There is no great difference between the alfalfa and regular drills other than that the feed cups and furrow openers are placed closer together on the alfalfa drills. The feed wheels are the internal, double-run, force-feed type and are made smaller than those on the regular drills. In some types of drills the speed of the grain feeds is changed by an arrangement of spur gears.
Draft of Grain Drills.- Kranich states that the draft of a plain drill will average around 6 pounds per opener per inch of depth.
The kind of seed being sown, the quantity in the seed box, the depth of seeding, the type of soil and its moisture content, the grade, and the condition of the drill are important factors that will influence the draft of a grain drill.
Broadcasting is the oldest and simplest method of sowing seed. When the sower went forth to sow, in the time of our Savior, he carried seed in a bag and broadcasted them by hand. Broadcasting with a machine is more accurate and rapid than when done by hand. Types of machine broadcasters are the knapsack, end-gate, two-wheel, and wheelbarrow.
Knapsack.- This seeder consists of a good-sized canvas sack fastened to a seeding mechanism, the whole being slung over the shoulders (Fig. 299). A crank turned by hand revolves a wheel having several different ribs for scattering the seeds. The ribs throw the seeds out to the front and sides in a steady stream. The quantity of seed is regulated by a sliding gate. The wider the gate is opened the more seed per acre will be sown. This type of seeder is good for sowing clover seed and small grass seed on lawns and fields in the early spring. Other types of knapsack seeders may have the wheel for scattering the seed placed in a vertical plane in front of the seeder. Still others, instead of having one wheel placed in a horizontal plane, may have two wheels, turning in opposite directions, placed opposite each other. The seeds are dropped on the inner sides and thrown to the front and sides.
End-gate Seeder.- The end gate is an attachment that is placed on the rear end of a wagon box (Fig. 300). It consists of a hopper, a feeding device, and either one or two distributing wheels. These radial-ribbed distributing wheels are driven by a chain and sprocket, receiving their power from the left rear wheel of the wagon.
Two-wheel Horse-drawn Broadcaster.- There are two types of two-wheel horse-drawn broadcasters: the narrow track and the wide track (Fig. 301). It is claimed that the narrow-track seeder (Fig. 302) is more practical where covering devices are not used. It also eliminates whipping of the tongue on rough ground.
Both types use the fluted-wheel type of feed. The narrow-track broadcaster has grain spouts hinged to the seed cups and are held in position by a stout coil spring. If a spout should strike a stump or other obstruction, it will swing back out of the way and then return to position.
Markers are provided at each end of the hopper on the narrow-track broadcasters. Markers are not necessary on the wide-track broadcasters, because the wheels leave a track which serves as a guide. Where it is desirable to cover the seed, two-wheel wide-track broadcasters can be obtained with hoe-type coverers. Seed boxes are available for mounting on disk harrows and one-way disk plows.
Wheelbarrow Broadcaster.- The wheelbarrow seeder is composed of a wheelbarrow frame with a long seed box mounted on the front end. This box is about 3 inches square and about 8 to 16 feet in length.