RU2583802C1 - Device for soil compaction - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the construction of soil compaction. It comprises a housing with a stove, an electric motor, on the shaft of which is rigidly fixed crank pivotally connected via a connecting rod to the driven crank shaft which is fixed imbalance. Links have a special arrangement of the transmission pivots: crossed from different angles α₁ and α₂ and spaced at the shortest distance l₁, l₂, and the associated value for $$\frac{l_1}{l_2}=\frac{\sin {\alpha }_1}{\sin {\alpha }_2}.$$

EFFECT: device provides controlled within wide limits inertial force which effectively compacts the soil and simultaneously moves forward or backward power device without involvement operatora.

2 cl, 3 dwg

Description

The invention relates to construction and can be used in ramming machines and devices for compaction of soil.

Closest to the proposed device is a device for immersion piles (Aut. St. USSR No. 1245656, M. cl. E02D 7/18. Publ. 23.07.86. Bull. No. 27).

The device comprises an electric motor, at the ends of the shafts of which two driving cranks are fixed, articulated by two connecting rods with two driven cranks with unbalances on the main necks, while the axis of rotation of the motor shaft is perpendicular to the rotation axes of the driven cranks and located at a distance equal to the length of the connecting rod. The axis of the hinges of the cranks of the right side are located at an angle α, and the axis of the hinges of the cranks of the left side are at an angle (180-α), while the driven cranks are fixed diametrically opposite in the housing.

The device is equipped with two additional driven cranks with unbalances, pivotally mounted with the main driven cranks and connected to them through the connecting rods, and their main necks are located coaxially in the housing.

The disadvantage of this device is the complexity of the transmission mechanism, consisting of two leading cranks, two connecting rods and four driven cranks with unbalances. A significant main disadvantage is the small value of the coefficient of uneven rotation of the driven cranks with unbalances, therefore, the inertia effect is not strong enough, which is why the use of four cranks with unbalances is caused.

The device has one position of the rotation axes of the leading and driven cranks - perpendicular, which significantly limits the functional range of the device and the ability to control the inertial effect on the object.

Power pulses are transmitted only in the vertical direction, it is not possible to use them at an angle, which also reduces the functionality of the work.

The purpose of the invention is to simplify the design of the device and increase the efficiency during compaction of the soil.

In FIG. 1 shows a General view of the device; in FIG. 2 is a graph of changes in inertial efforts; in FIG. 3 is a diagram of the forces of influence when the body is tilted with unbalances; in FIG. 4 - photo of the prototype of the housing 6 with gear links 2, 3, 4 and unbalance 5.

Distinctive features of the proposed device in comparison with the prototype are:

- a significant simplification of the design by reducing the number of movable links in the proposed 3, and the prototype 10;

- the geometric axis of the hinges of the housing and connecting rod are crossed at an angle α ₂ , taking values from 30 to 90 °, in the prototype only at an angle of 90 °;

- the coefficient δ of non-uniformity of rotation of unbalances is many times larger: for α ₂ = 30 ° the range is from 2.59 to 27.71: for α ₂ = 45 ° the range is from 1.42 to 4.44; the prototype has a range from 0.59 to 1.15 (see table 1), therefore, the effect of the prototype is significantly and significantly less;

- the housing is pivotally connected to the plate with the possibility of rotation through an angle β forward or backward, which allows the device to self-move without operator effort, in the prototype the housing is rigidly connected to the pile;

- power pulses are transmitted both vertically and obliquely with respect to the plate, in the prototype only vertically;

, в прототипе l=l₁sinα;- the values of the crossing angles α ₁ and α ₂ , l ₁ and l ₂ and their ratio

, in the prototype l = l ₁ sinα;

This goal is achieved by the fact that one crank 2 is mounted on the shaft of the electric motor 1 (Fig. 1), pivotally connected by a connecting rod 3 to the driven crank 4, to which the unbalance 5 is rigidly connected.

The electric motor 1, the rotation shaft 2 'of the driving crank 2 and the shaft 4' of the driven crank 4 are located in the housing 6 at an intersection angle α ₂ .

The peculiarity of the cranks, connecting rod and housing is in the special arrangement of the geometric axes of their hinges, the combination of which significantly affects the magnitude and adjustment in a wide range of inertia forces.

So, the axes of the hinges of the cranks 2 and 4 are crossed (crossed - that means they do not intersect and are not parallel to each other) at an angle α ₁ and are separated by the shortest distance l ₁ , and the axes of the hinges of the connecting rod 3 and the geometric axes of the shafts 2 'and 4' of the cranks 2 and 4 are crossed at an angle α ₂ and are located at the shortest distance l ₂ . The parameters are related by

The angle α ₁ can take values from 10 to 50 °, and the angle α ₂ from 30 to 90 °. It should be noted that the shortest distances at the hinges of the cranks and the housing are measured not on the material body, but are located outside the body.

The housing 6 is pivotally connected to the plate 7 by means of a finger 8. The housing 6 together with the crank located on it with an unbalance 5 can change the angle of inclination with respect to the plate 7 both forward and backward. The angle is changed by means of the lever 9 and the rod 10. The lever 9 is pivotally connected to the plate 7 and pivotally to the housing 6 by the rod 10. The lever 9 fixes one of the positions of the housing 6 on the gear sector 11 by means of a latch (not shown in the diagram).

For manual movement of the device, it is equipped with a rod 12, pivotally connected to the plate 7.

The device operates as follows.

From the electric motor 1, rotation is transmitted to the leading crank 2, which rotates the driven crank 4 with unbalance 5 through the connecting rod 3. Due to the special arrangement of the hinge axes of the cranks 2 and 4, the connecting rod 3 and the axes of the housing 6, the driven crank 4 together with the unbalance 5 will have a variable one revolution, the angular velocity, the coefficient of uneven rotation of which is determined by the expression

The maximum ω _max and minimum ω _min value of the angular velocity of the driven crank with unbalance are determined by the expressions

where ω is the angular velocity of the leading crank 2.

When you change the angular velocity appears acceleration of the rotating unbalance 5, equal to

where r is the distance from the axis of rotation of the unbalance to the center of its mass;

ω is the angular velocity of unbalance rotation;

γ is the angular acceleration of unbalance rotation.

As a result, an inertia force P equal to P = m · a appears (here m is the mass of unbalance).

At moments when the angular velocity ω of unbalance rotation takes maximum and minimum values, the angular acceleration is zero and the maximum and minimum values of inertia are respectively

An example of a structural embodiment of the device, with the adopted unbalance mass m = 10 kg, r = 0.1 m, ω = 10 s ^-1 , α ₁ = 20 °, the minimum and maximum pulses will be equal to:

For α ₁ = 60 ° and the same data, m = 10 kg, r = 0.1 m, ω = 10 s ⁻¹ pulses are equal

As you can see from the example, with an increase in the angle α ₁ , the inertia force increases significantly, while the maximum value of the force at an angle α ₁ = 20 ° will be 4.2 times greater than the minimum, and at an angle α ₁ = 60 ° the maximum value will be 192 times greater than the minimum value of force.

In FIG. 2 indicated: P _max , P _min , F _Tr - the friction force of the plate on the soil surface. The area bounded by the curve P = f (t) and located above the abscissa axis (time axis of one revolution) is a momentum of force in a downward direction perpendicular to the plane of the plate, while the device body 6 is located vertically, i.e. perpendicular to the plane of the plate.

The area of the curve P = f (t), located under the abscissa axis of this graph, represents the momentum of the force P in the opposite direction.

In accordance with the law of conservation of momentum, the values of these pulses are equal, i.e. equal to the area above the axis and the area under the abscissa. However, due to the uneven rotation of the unbalance, the amplitude of the force P down significantly exceeds the amplitude of the force P in the opposite direction, which creates the effectiveness of compaction. This seal will be carried out in one place under the stove.

To move the device forward, it is necessary to move the lever 9 back, as a result of the thrust 10 will rotate the housing 6 along with the unbalances by a certain angle β and the inertia force will be directed at an angle β (Fig. 3a). Force F resolved into two forces: downwards - P _ext = Pcosβ and forth - R _wp = Psinβ.

The force P _int will compact the soil, and the force P _int will move the device forward without operator effort. The course of movement will depend on the angle β and the ratio of the forces P _VP and the friction force F _Tr = mgf (f is the coefficient of friction).

In the graph of FIG. 2 shows the friction force, which is greater than the minimum inertia force P _min = P _VN , the device does not move backward. Since the force P _VP exceeds the friction force, the device will move forward, while compacting the soil.

For backward travel must lever 9 rotate forward rod 10 will turn body 6 forward component P _sn inertia force (Fig. 3b) is guided back and accordingly, movement of the device will be back.

Thus, the device simultaneously performs soil compaction and moving forward or backward without the force of the operator. The process of compaction and movement of the device is carried out from one source-electric motor.

In FIG. 4 shows a photo of a prototype case with movable links 2, 3, 4 and 5, the angle α ₂ in the device is 45 °.

The regulation of the power pulse in the device can be carried out at the design stage, i.e. assignment of the angles of intersection of the hinge axes α ₁ and α ₂ , on which the coefficient of uneven rotation of the unbalances depends. The options for the parameters of the cranks (α ₁ , l ₁ ), determined by the expression (2), connecting rod and housing (α ₂ , l ₂ = 200 mm) are given in table 1 (l _{2 is} taken equal to 200 mm).

The table shows that the greatest value of the coefficient δ of the unevenness of rotation of the unbalance takes at a crossing angle α _{2 of the} axis of rotation of the cranks (axes of the housing 6) and a connecting rod of 30 and 45 °, the angle α _{1 is} suitable from 20 to 30 °.

Crossing angles α ₂ = 60 ° and especially α ₂ = 90 ° are undesirable due to the insignificant coefficient of uneven rotation and low efficiency of the inertial force.

This is a convincing confirmation of a significant drawback of the prototype, which used four unbalance instead of one of the proposed device.

The degree of compaction can be controlled by the frequency of rotation of the unbalances, i.e. changing the frequency of rotation of the motor shaft. Additionally, you can increase the effect of compaction by adding interchangeable unbalances, as well as by increasing the weight of the plate or by loading it with an additional load.

Claims (2)

1. A device for compaction of the soil, containing an electric motor, a crank mounted on its shaft and a driven crank with unbalance pivotally connected to it by means of a connecting rod, placed on the housing with a plate, characterized in that, in order to simplify the design and increase the efficiency of the device, geometric axes the hinges of the cranks are crossed at the same angle α ₁ and are located at the shortest distance l ₁ , and the geometric axis of the hinges of the connecting rod and the geometric axis of rotation of the cranks (housing axis) are crossed at an angle α ₂ and about are at the shortest distance l ₂ , while the parameters are related by the relation

2. The device according to claim 1, characterized in that the housing is pivotally connected to the plate with a possibility of rotation and is equipped with a locking device, for example, a lever with a latch.

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