Tab.1 Input datas to operational analysis of a reel

№ Вар	Ширина захвата Культиватора В (м);	Скорость движения культиватора (км/час),	Глубина обработки, а (см)	Кол-во рядов культиваторных лап;	Угол 2γ при вершине стрельчатой лапы (град);	Конструкт. ширина лапы, в мм		Коэфф. трения почвы о лапу
								0, 60
								0, 51
								0, 55
								0, 60
								0, 40
								0, 37
								0, 38
								0, 51
								0, 53
								0, 57
								0, 47
								0, 40
								0, 49
								0, 53
								0, 60
								0, 61
								0, 54
								0, 43
								0, 61
								0, 57
								0, 57
								0, 60
								0, 53
								0, 47
								0, 55
								0, 59

 

5 Technological calculations 5.1 Calculation of parameters of paws In this section of the term paper it is necessary to calculate a corner 2γ at top of a lancet paw, the rational size of overlapping ∆ в, capture width in, to choose other parameters from the recommended values.

Input datas are types of soils, the necessary shift S weeds guaranteeing it cutting or a gap.

Figure 1. Lancet cultivator paw.

 

Cultivators for preseeding processing of the soil are completed with strulchaty paws. Lancet cultivator paws are intended for destruction of weed plants, they work at depth of 6-12 cm, and sometimes to 25 cm. A lancet paw which can be with a shaft or without it. The key design data of a lancet paw are characterized by cone angles 2γ and dyeing β; with capture width in, and also width at the beginning v1 at the end v2 covered paws and an outline of a breast of a paw (fig. 1).

Figure 5. The scheme to justification of a corner γ: and – cutting with sliding;

– cutting without sliding.

It is necessary to calculate the necessary size S of a bend and shift of a weed which will provide the given overlapping of paws.

Figure 6. Determination of size of movement S weeds under the influence of a paw

At arrival on a weed About (fig. 9) the edge of a paw presses on its root and causes a bend and shift it on the OO1 line rejected from a normal to an edge on a corner φ. If by the time of‚ a descent from a paw wing the weed is not cut, then it will

 

be displaced on distance

(2)

where ∆ в - overlapping between paws. ∆ в = 50 mm.

φ - a weed sliding angle on an edge. φ ≈ 47, 70

The probability of survival only of the defective weed increases with decrease of shift of S.

And expressions (2) it is visible that S decreases with decrease of overlapping and a corner γ. Having defined the recommended overlapping, we will calculate according to (2) size of shift of a weed for the projected cultivator. We accept overlapping between paws ∆ в =50 mm for a corner γ = 55.

Then the shift of S will be equal

 

Width of capture of paws is chosen taking into account that this parameter influences a congestion of not cut weeds on the ends of their wings too. Conformal coating of edges the shirokozakhvatnykh of paws and lack of conformal coating the same operating conditions of the paws of small width of capture having identical value of corners 2 γ and β is noted by many authors. This phenomenon has not static, but dynamic character, i.e. the edge is shrouded in not movably hung weeds, and sluggishly along it sliding.

Figure 7. Process flow diagram of dynamic conformal coating by weeds of an edge of a pololny paw.

When moving a paw in the friable soil from situation I in situation P (fig. 4) all weeds, находящиея on the area of ABCD, will be broken from the place and, moving together with a paw and at the same time sliding along its edge, will accumulate on the site of an edge of CD

Quantity of weeds on this site of an edge: (3)

where ί -number of weeds on a field unit area;

L-centerline of a trapeze;

h-ABCD trapeze height.

Accumulation of weeds on an edge usually is found on the end of a wing. This results from the fact that paws of larger width of capture are established on a cultivator in the second row.

The ends of wings of these bark move in the soil loosened with paws of the first row therefore the head resistance of a weed on the end of a wing can be poor in order that the tangential component of this effort was capable will overcome besides frictional force also shearing strength of the layer of earth which stuck to the surfaces of a paw: a weed, sliding along an edge, has to clear this layer of soils from a paw.

From (fig. 4) it is visible that the site of CD of an edge of a paw is the most loaded by quantity of the weeds passing through it in case of not cutting with their other sites of an edge. Let's choose lengths of the site of CD = ∆ l according to overlapping of paws: (4)

then for ensuring immediate contact of weeds with an edge their quantity on this site of an edge has to be no more (5)

where d-effective diameter of a stalk of a weed.

For this calculation it is possible to accept mm d≈ 4.

.

 

The area of a trapeze with which weeds were going to the site of ∆ l of an edge, is defined by height of ∆ h and lengths of the parties of AD and BC (6)

(7)

 

(8)

Considering equality (3), it is possible to check width of capture of a paw with which conditions of cutting of weeds will be satisfactory even on the ends of wings: (9)

Let's calculate ∆ h: ∆ h₁=30*cos 47, 7/sin17, 5=111, 9 мм,

∆ h₂=50*cos 47, 7/sin27, 5=72, 87 мм

 

We accept в1=200 mm, then А₁D₁=200/2cos(17, 5+47, 7)=321, 848 мм

B₁C₁=321, 848 +58-146, 546=221, 549 мм

L₁= А₁D₁+ B₁C₁/2

L₁₌321, 846 +221, 549 /2=432, 622 мм

Having substituted a formula (3) in a formula (9) we will receive: в≥ ∆ в₁+[ (2_* ί _* L_1*∆ h₁)_* cos(φ +γ )_* sin γ / ί _*∆ в_1*cosφ ] (10)

then в1 numerically it is equal: в₁=30+[ (2_*432, 622 _*111, 9)_* cos(47.7+17, 5)_* sin22, /30_*cos47, 7]=450, 85 мм

the condition satisfies, means truly.

Now we will calculate for a corner γ = 27, 5

We accept в2=260 mm, then А₂D₂=260/2cos(27, 5+47, 7)=608, 914 мм

B₂C₂=608, 914 +68, 8-362, 58=625, 76 мм

L₂= А₂D₂+ B₂C₂/2

L₂₌608, 914 +625, 76 /2=921, 795 мм

в₂≥ 50+[ (2_*921, 795 _*72, 87)_*cos(47.7+27, 5)_* sin27, 5/50_*cos47.7]=189, 75 мм

the condition satisfies, means truly.

The received result should be compared to recommendations of practical character: for sticky clay soils в< 35 cm, for sandy в< 45cm **************************************************

At the choice of width of capture of a paw according to expression (9) it is necessary to provide two values of this parameter; paws of a back row go on partially processed soil therefore they experience smaller strain and can be wider, than paws of a forward row. By analogy to reference values it is possible to accept the relation: (11)

Let's determine width of capture of paws of a row

************************************************************

Extent of the loosening of the soil made by a paw is defined by the size of an angle of dyeing β and wing width: the corner β is less and the paw wing is more narrow, the loosening of the soil is less. β paws are divided by corner size on ploskorezny β = 12-180 and the universal β = 25-300.

Paw wing width is usually done reducing by the end.

Minimum width covered в2=30-50 mm, and maximal в1=1, 5 в2

We accept the minimum width of a wing в2 = 50 mm, then в₁=1, 5*50 = 75мм

 

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Paw breast angle of lead α, formed by the AV line (fig. 9.) with a plane of support it is bound to cone angles and dyeing, it can be found on a formula: (12)

After substitution and calculation we receive tg α = tg 15* sin 17, 5 = 0, 27*0, 3 = 0, 08

we receive, a corner α = 5, 1

tg α = tg 25* sin 27, 5 = 0, 46*0, 537 = 0, 215 we have, the angle of lead of a breast of a paw will make: α = 16⁰

 

 

 

L piece defining the provision of a point In is equal (13)

Further we find: l₁= 75*0.258/0, 1010 = 165 мм

l₂= 57*0, 422/0, 242 = 127, 32 мм

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Depending on corners β dyeing and α rise choose a type of sharpening of paws: top (at β ≤ 150); lower (at β & gt; 250); kobinirovanny bilateral (at 150 & lt; β ≤ 250). Usually accept the angle of sharpening ί = 12 … 150.

We accept sharpening of an edge combined.

Figure 8. Combined method of sharpening of an edge of a paw.

 

For ensuring stability of the course of paws on depth the edge has to have the positive back angle of cutting ε ≥ 100 in wing section the vertical plane, perpendicular to an edge. On properties of the material applied to manufacture of paws the point corner ί should not be less than 12-15 °. Forward angle of cutting β 0 = ί + ε = (12÷ 150) +100 = 22÷ 250. There fore we accept sharpening of an edge combined. ******************************************************************

Material thickness δ is chosen depending on capture width: for the universal δ ≤ 0, 03в then δ ≤ 0, 03*260 = 6, 8 мм.

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