SU1391874A1 - Percussive machine - Google Patents

Abstract

This invention relates to percussion machines. The purpose of the invention is the increase in the effectiveness of vibration protection. The best result is obtained when choosing the stiffness C of the torsion springs from the ratio C (0.09 ... 0.24) x X С iVin, j5 where C, is the coefficient l: e of the stiffness of the elastic element 21 installed between case 1 and box 19, the masses of the body 1 and the handle 11, respectively. 2 ill.

Description

(L

with

with so

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The invention relates to percussion machines and can be used in construction and mining.

The purpose of the invention is to increase the efficiency of vibration protection.

FIG. 1 shows a percussion machine, general view; in fig. 2 is a sectional view of FIG. one.

The percussion machine includes a housing 1, an engine and a gearbox (not shown), a conversion mechanism 2 in the form of a crankset.

In the housing 1, a cylinder is mounted, a j-cylinder 3, in which the hammer 4 and the piston 5 are located. An airbag 6 is formed between the hammer 4 and the piston 5 "Dp to compensate for the loss of air from the airbag 6 in the stationary cylinder 3 there is a side hole 7. On the body 1, a base 8 (Fig. 2) is fixed with an eye 9, an axis 10 for swivel vibrating 1t handle 11. Elastic elements in the form "g torsion springs 12 are freely mounted on a sleeve 13 made of vibration damping material worn on the axis 10 of the swivel joint , and the ends 14 and 15 of the springs 12 are twisted and supported on the damping elements 16 and 17, fixed respectively on the base 8 and the body 18 of the handle. The springs 12 and the sleeve 13 are located across the current vibration. In the case 1 a box 19 is installed, in which the working tool 20 is placed. Between case I and box 19 there is an elastic element 21. At the same time, the stiffness Ci of the elastic element in the form of a torsion spring 12 between the box 1 and the handle 11, is selected from the ratio

Cr (0.09 ... 0.24) -Ci

mi m.

where C. is the stiffness coefficient of the yn ™ of the other element 21 installed between the housing 1 and the axle box 19;

t and ffij-masses, respectively, of the housing 1 and the handle 11. The percussion machine operates as follows.

In operation, the motor rotates through a gearbox (not shown) and the conversion mechanism 2, in the form of a crank assembly, is converted into air

reciprocating movement of the piston 5.

FIG. 1 shows the device in the initial position. When the piston 5 moves upward from the position of the bottom dead center in the air cushion 6, a vacuum is formed. The negative vacuum pressure opens the impactor 4 from the working tool 20, and the impactor 4 moves after the piston 5. At the same time, air is drawn in through the side opening 7, and thus the air loss from the airbag 6 that took place during the previous cycle is compensated.

The diameter of the side opening 7 is selected so that the speed of movement of the striker 4 does not change with a change in vacuum. When the piston 5 is in the top dead center, the airbag 6 is stretched. When the conversion mechanism 2 and the piston 5 pass through the top dead center, the piston 5 moves towards the striker 4. The latter moves along HHepniiiH, the vacuum in the air cushion 6 decreases and at a certain point in time the air pressure in the air cushion 6 becomes equal to atmospheric.

When the striker 4 and the piston 5 approach each other, the air pressure in the air cushion 6 increases until the elastic force of the compressed air is stopped by the striker 4.

The compression pattern of the air bag 6 is transmitted to housing 1.

When the machine is working on the housing 1, a broadband spectrum of vibrations is generated, excited by the impacts of the impactor 4, it rotates them with the details of the engine, gearbox, and the conversion mechanism 2. The reduction of vibrations on the handles is achieved by the simultaneous use of vibration insulation, damping and dynamic damping of vibrations of the housing 1.

The torsion springs 12, pre-twisted and freely mounted on the sleeve 13 of a vibration-suppressing material worn on the axis 10 of the hinged joint of the handle 11, are highly flexible and therefore provide the necessary coefficient of vibration isolation. Best result

is obtained by choosing the stiffness C of the torsion springs 12 from the ratio

mr

Cj (0.09 ... 0.24) C, -

t,

where C is the stiffness coefficient of the elastic element 21 installed between the housing 1 and the axle box 19; t / yoke, - masses, respectively

Enclosures 1 and handles 11, Moving the handles AND (static) with the application of force pressing the operator less than the free movement of the hands.

Preliminary deformation of the torsion springs 12 is carried out by diluting the ends 14 and 15. Due to the friction of the supporting ends 14 and 15 against the surface of the damping elements 16 and 17, a structural damping effect occurs.

The absorption capacity of the handles 11 depends on the contact pressure of the ends 14 and 15 of the torsion springs 12 onto the surface of the damping elements 16 and 17.

The peculiarity of vibroprotective handles is that with an increase in the impact energy of the striker 4 from 25 to 100 J, the vibration insulation and vibration absorption rates can be increased without changing the basic and connecting dimensions of the torsion springs 12 by decreasing the working turns and increasing the angle of the ends of the 14 and 15 springs. 12 twists.

The arrangement of the torsion springs 12 and the sleeve 13 across the existing vibration increases the effect of functional damping, since the springs

12 torsion interacts immediately with three damping elements — a sleeve 13 and two damping elements 16 and 17. As a result, the vibration protection of the operator is increased by increasing the vibration absorption coefficient of the handle 11.

When oscillatory motions of the masses of the housing 1 and the handles of the machine 11 are made, the vibrational energy is redistributed and a dynamic quenching of the oscillations of the mass of the housing 1 occurs.

In this case, the frictional damping accompanying the oscillations of the elastic system of the PCA 1 1 1 expands the frequency range within which the dynamic damping of the oscillations of the body 1 of the machine takes place.

Claims (1)

Invention Formula A percussion machine comprising a body, a handle, an axle box, a working tool and elastic elements installed respectively between the handle and the body and between the body and the axle box, characterized in that, in order to increase the effectiveness of vibration protection, the rigidity of the elastic element mounted between the body and the handle is chosen from the ratio Cj (0.09 ... 0.24) - - the stiffness coefficient of the elastic element installed between the body and the axle box; masses of the body and the handle respectively. 1Z, 3 1c Fi.g