Here is a list of equipments used for harvesting of crops: 1. Impact Cutter 2. Sickle 3. Mower 4. Reaper 5. Groundnut Digger Shaker 6. Potato Digger Elevator.
Equipment # 1. Impact Cutter:
An impact cutter has single element moving at high speed and operates by Inertia of the material being cut to furnish the opposing force required for shear.
Types of Impact Cutter:
Impact cutter is of two types:
1. Rotary Cutters
2. Flail Shredders
1. Rotary Cutter:
A rotary cutter has knives rotating in a horizontal plane (such as rotary lawn movers).
2. Flail Shredders:
It has knives rotating in vertical planes parallel to direction of travel. Rotary cutters with effective width of 1.0 to 2.1 m have a single rotor usually with 2 or 4 knives, on the ends of radial arms. Wider units have at least 2 or 3 rotors each generally cutting a width of 0.7 to 2.1 m. The total cutting width may be 6.1 m.
Peripheral speeds generally range from 51 to 76 m/s. Knives or support arms can be shaped to create an up draft, which raises lodged material and lifts cut material for further size reduction. Knives are usually attached to the support arms through vertical hinge axis so they can swing back if an obstruction is hit.
Flail shedders have free swinging knives or flails 50 to 150 mm wide attached to the rotor in 3 or 4 rows staggered so the cuts overlap slightly. Manual harvesting involves slicing and tearing action.
Harvesting can be done by:
1. Manually operated tool
2. Animal drawn machine
3. Mechanically operated machine
There are a few related terms in connection with harvesting, which are as below:
It is a machine to cut herbage crops and leave them in swath.
It is a machine to cut grain crops.
iii. Reaper Binder:
It is a reaper which cuts the crops and ties them into neat and uniform sheaves.
It is the material as left by the harvesting machine.
It is a curved steel blade having a hand grip used for harvesting by manual power.
It is a row of material formed by combining two or more swaths.
It is a machine to cut crops and deliver them in an uniform manner in a row.
Equipment # 2. Sickle:
Sickle is a simple harvesting tool. It is used for harvesting crops and cutting other vegetation. It essentially consists of a metallic blade and a wooden handle.
Sickles are classified into two classes:
1. Plain, and
Blade is the main metallic part of the sickle. It is desirable to make the blade made of carbon steel. The blade is made in a curved shape. The teeth of serrated sickle are made sharp for efficient working in the field. The handle of the sickle is made of well-seasoned wood.
The forged end of the blade for fixing the handle is called Tang. The plain or serrated edge in the inner side of the blade is called cutting edge. Protective metallic bush fitted at the junction of the blade and the handle to keep the tang tight in the handle is called Ferrule. Harvesting by sickle is a very slow and labour consuming device.
Equipment # 3. Mower:
Mower is a machine to cut herbage crops and leave them in swath.
There are different types of mower used in different ways such as:
1. Cylinder Mower
2. Reciprocating Mower
3. Horizontal Rotary Mower
4. Gang Mower and
5. Flail Mower
1. Cylinder Mower:
It has rotating helical blades arranged in horizontal cylindrical form. With the rotation of blades, forage or grasses are cut continuously.
2. Reciprocating Mower:
It is a mower with a knife having sections that reciprocate against stationary fingers. It is most common type of mower used everywhere.
3. Horizontal Rotary Mower:
It is a mower with high speed knife rotating in the horizontal plane. Due to rotation of knife, the grasses and forage are cut in uniform way.
4. Gang Mower:
It is an assembly of two or more ground driven cylinder mowers.
5. Flail Mower:
It is a mower with high speed swinging knives, operating either in a horizontal plane or around a horizontal cylinder. Out of all these mowers, reciprocating mower is commonly used everywhere.
Depending upon the source of power, mower can be classified as:
i. Animal drawn and
ii. Tractor drawn
The basic components of both these mowers are same but main difference lies in power transmitting unit only.
Conventional Type of Mower:
The conventional mower mainly consists of:
2. Power Transmitting Unit
3. Cutting Bar
5. Ledger Plate
6. Wearing Plate
8. Grass Board and
The frame provides space for gears, clutch and bearings. The lever for lifting the cutting bar is attached to the frame. A flywheel is used to store energy to provide steady speed to the cutting mechanism.
2. Power Transmitting Unit:
In bullock drawn mowers, the power transmitting unit consists of axle, gears, crank wheel, crankshaft and pitman. The transport wheel gives power to the axle from where the power is transmitted through the gear box. The crank wheel and the pitman are fixed on the outer end of the crankshaft.
Reciprocating motion is transmitted to the pitman, which operates the knife in the cutter bar. There is ball and socket arrangement to connect the knife with the pitman. The operator controls the driving unit with the help of a dog clutch.
Tractor drawn semi-mounted or mounted type mowers are operated by pto shaft. In this case, the cutting mechanism is driven independently of the forward speed of the mower. A shaft is connected with the pto shaft which drives a pulley with the help of a universal joint.
This V pulley rotates another smaller pulley on the crankshaft of the machine and reciprocating motion is transmitted to the cutter bar. Other basic components of the machine are the same as that of bullock drawn mower with some variations in size and minor accessories. Trailed type mower has got the basic components same as that of bullock drawn mower.
3. Cutter Bar:
It is an assembly comprising of fingers, knife guides, on wearing plates and shoes. It is used for cutting grasses and forage. It is made of high grade steel. It works like a knife. The knife is a metal bar, on which triangular sections are mounted. The knife section makes reciprocating motion and cuts the plants. There are knife guards, provided on the cutter bar.
The knife stops at the centre of the guard on each stroke. There are ledger plates provided with the knife guard, on which the knife moves. Knife clips hold the sections down against the ledger plates. Knife clips are placed with wearing plates spaced 20 to 30 cm apart.
A shoe on each end of the cutter bar is always provided to regulate the height of cut above the ground. The inner shoe is larger in section and is placed at the inner end of the cutter bar. The outer shoe is placed at the outer end and is smaller in section.
5. Ledger Plate:
It is a hardened metal inserted in a guard (finger) over which knife sections move to give a scissor like cutting action.
6. Wearing Plate:
It is a hardened steel plate attached to the finger bar to form a bearing surface for the back of the knife.
It is the reciprocating part of the cutter bar, comprising of knife head, knife back and knife sections.
i. Knife Section:
It is a flat steel plate (triangular shape) with two cutting edges.
ii. Knife Head:
It is the portion of the knife which is connected to the pitman.
iii. Knife Back:
It is the strip of steel to which knife sections are riveted and the knife head is attached.
8. Grass Board:
Grass board is provided at the cutter end-of the mower which causes the cut plants to fall towards the cut material. Shoes are provided for easy and smooth sliding of the cutter bar.
Pitman is a type of connecting rod which is pinned to the crankshaft, with the help of a pin. It transmits reciprocating motion to a knife head. Wooden pitman is commonly used for the mowers.
Breaking of Knives:
Breaking of knives is a common trouble in operation of a mower. It is caused due to play in bearings and worn knife head holders. Non-alignment is an important cause for breaking the knife because
when the mower is out of alignment, it works on a certain angle which is always harmful.
Alignment of Mower:
Under working condition of the mower, the standing crops exert pressure on the cutter bar tending to push it backward. In correct operating position, the crank pin, knife head and the outer end of the knife should be in a straight line. This line should be at right angle to the direction of travel of the mower.
For achieving this object, the cutter bar is set at about 88° to the direction of motion i.e. inward lead of 2° is given to it in order to overcome the back pushing action of the crops. When the cutter bar is properly aligned, the knife and the pitman rim in a straight line. This gives better cutting in the field. Generally 2 cm lead per metre length of cutter bar is recommended.
Registration of Mower:
A mower knife is said to be in proper registration when the knife section stops in the centre of its guard on every stroke i.e. the centre of the knife section is at the centre of the guard, when it is in operating condition. Adjustment is commonly made by moving the entire cutter bar in or out with respect to the pitman. If mower is not well registered, there is unbalanced load, uneven harvesting and excessive clogging of crops on the knife.
Equipment # 4. Reaper:
Animal Drawn Reaper:
Reaper is a machine to cut grain crops. Animal drawn reaper is getting popular gradually in the country. It is pulled by a pair of animals. It can harvest nearly 5 to 8 cm above the ground. The machine consists of frame, cutter bar, knife, wheels, bearings and other attachments. Frame is usually made of mild steel sections.
The cutter bar knife is made of high carbon steel. The shoes are usually made of malleable casting. Ball bearings are used for efficient and durable working. Usually two persons are required to operate the machine. One man guides the animals and another man is engaged in dropping the cut crops from the platform to the ground.
Care and Maintenance:
1. Wheel hub bearings, flywheel shaft bearings and pitman bearings should be well lubricated.
2. Knife bar should be sharpened at regular interval. It is desirable to sharp the knife after about 30 working hours.
3. All the nuts and bolts should be checked before taking the machine to the field.
Vertical Conveyer Reaper (Tractor Mounted):
It is mostly used for harvesting paddy and wheat. The reaper is front mounted at the tractor which can be lowered and raised by the hydraulic control. It is powered by the pto of the tractor. Crop is guided by the star wheel to the cutter bar and held in vertical position by the springs. The crop is conveyed to the side by the conveyer belt. Its capacity may be 0.4-0.6 ha/hr.
Vertical Conveyer Reaper (Power Tiller Operated):
It can be used for harvesting wheat and paddy. The reaper is front mounted on the power tiller. Power is transmitted from the engine flywheel to the reaper either through “V” belt or by providing gear box and propeller shafts. Crop is guided by the star wheels to the cutter bar and held in vertical position by the springs. The crop is conveyed to the side by the conveyer belt. Cutter bar length may be 100-160 cm. The capacity may be 0.25-0.35 ha/hr.
It cuts and binds the crop simultaneously It cuts the crop at the height of about 10 cm from the ground level. The harvesting capacity is 0.25-0.35 ha/hr.
Equipment # 5. Groundnut Digger Shaker:
It is used for digging of groundnut crop. It is a tractor mounted pto operated machine, suited for harvesting of both erect and spreading varieties of groundnut crop, grown in all types of soil. It consists of digging blade and a spike tooth conveyer.
Equipment # 6. Potato Digger Elevator:
It is used for digging and windrowing the potatoes. The equipment is a pto operated single row machine. The machine consists of cutting blade and elevator roller chain of iron bars. The potatoes are dug by the blade and lifted to a conveyor which is under periodic shaking. The potatoes are delivered at the rear of machine and collected manually.
It is a tractor rear mounted pto driven machine. Its capacity may be 0.15-0.2 ha/hr. It can be operated by a 20-25 hp tractor. The groundnut vines are loosened by the blade and whole crop is lifted and shaken by conveyor chain to remove all the soils. Thereafter the vines free of soil are dropped and windrowed behind the machine. The vines are collected manually.