FI123463B - Impact medium powered impactor - Google Patents

Description

PRESSURE MEDIUM IMPACTOR

The invention relates to a percussion device operating on a pressurized medium, such as hydraulic fluid pressurized fluid 5, comprising an elongated body attached to a work machine, a movable impact mass mounted on said body having a linear guide member mounted on said body and a piston rod, said rigidity having said piston rod secured to said mass and a valve assembly for directing the hydraulic fluid pressure to the first cylinder on the other side of the piston for lifting the mass and abruptly reducing said pressure by directing the impact.

, It is known to use a retractable mass for a 15 mm downward impact device. from WO 03097945, where a plurality of hydraulic cylinders are disposed outside the pulp, which both raise the pulp and also provide a pressure in the gas spaces on the other side of the pistons in the cylinders to accelerate the pulp at impact. During the stroke, the hydraulic pressure is released from the cylinders. This solution has the disadvantage that during the stroke, the hydraulic fluid is not able to leave the ground cylinder sufficiently fast because it has to be led along a return line to the unpressurized tank of the system. The return line generates back pressure and the impact with compressed gas is somewhat ineffective. Thus, the problem is the flow resistances of the return line when a sudden return of hydraulic fluid is required.

^ 25 Another disadvantage of the solution described above is that the device becomes wide when the cylinders are positioned

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, placed on the sides of the moving mass. The forces exerted on the pulp have to be laterally guided from the cylinders by means of special arms, whereby the arms become very heavy. It is difficult to make guides to guide the mass because the cylinders are at the same position outside the mass. Each cylinder requires its own valve, because valves S 30 must be installed as close to the cylinder as possible. Further, the gas spaces in the cylinders are difficult to obtain effective cooling.

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Also known from US 3695366 is a percussion device in which the hydraulic fluid that lifts the piston is conveyed away from the front of the surface of the piston during the stroke to reduce its back pressure in the stroke. Further, GB 2089407 discloses a similar percussion device in which the pressurized fluid is to be discharged from the face of the piston lifting surface during the impact. However, fluids are not conducted into the expanding space during the stroke.

The impact device of the invention achieves substantial improvements in the prior art, and the invention is characterized in that during the impact of the mass, the hydraulic fluid returning from the cylinder space of the first cylinder is controlled by a valve assembly to

An advantage of the invention is that during the acceleration of the pulp, the back pressure caused by the hydraulic fluid suddenly leaving the cylinder is substantially reduced when it can be applied for a moment to a nearby space expanding at the same time. As the mass is raised 15 up to the impact capability, the hydraulic fluid is removed from this space to the return line, but this removal need not be abrupt. The impactor is thus provided with a breathing space in the invention which receives and removes the pressure fluid in a timely manner at the rate of the strokes.

The structure according to the invention also makes the mass moving forces behind the mass 20 effective on the same line as the mass moves. Further, in the cylinder spaces where the gas is heated by compression, effective cooling is obtained when the lower temperature variable hydraulic fluid circulates behind one of the highly conductive walls and cools the gas spaces through the wall. The impactor can take advantage of many different stroke lengths and mass movements, allowing the mass to be raised to its upper 25 head position without unduly compressing the gas, even with the pre-pressure set.

In the following, the invention will be explained in more detail with reference to the accompanying drawings in which

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Q- Figure 1 shows a side view of an apparatus according to the invention.

Fig. 2 shows the apparatus of Fig. 1 with added impact mass and the structures required by it.

Fig. 1 shows a percussion device, from which the hollow arm protruding 1 acts as a lifting arm for lifting the impact mass and as a lever for transmitting to it the accelerating force. At the end of the arm 1 there is a fastening part 9 for fixing it to the impact mass. The arm 1 also acts as a piston rod 3 for the piston 16, which is moved by hydraulic pressure. Hydraulic pressure is controlled from valve 15 along line 14 to front of piston 16 (left side). At the rear (right side) of the piston 16 is a cylinder space 4, which is limited to an annular space by an inner tube 3. 5 The outer surface thereof is a cylinder tube 20.

The piston 16 and the piston rod 1 slide sealed on the inner tube. The cylinder space 4 is filled with nitrogen gas to a suitable pre-pressure. From the cylinder space 4, the openings 17 lead to an outer annular space 5, which thus also acts as a storage for nitrogen gas 10 and, due to the openings 17, is also pressurized as the space 4 is pressurized. The outer surface of the annular chamber 5 is formed by the outermost tube 21. As the nitrogen gas is continuously flowing through the apertures 17 into and out of the annular space 5, the hydraulic fluid supplied to the annular space 6 effectively cools the nitrogen gas;

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The piston 16 is lifted by the piston 16 and the cylindrical space 6 in front thereof receives pressurized hydraulic fluid through the conduit 14. During the stroke, the hydraulic fluid returns along the same conduit 14 in a very sudden discharge. In order to prevent back pressure, the return fluid is directed through the valve assembly 15 to the interior space 2 of the inner tube 3, which is at present the expanding state because the piston rod 1 moves outwards. Only a short, relatively large diameter tube 14 remains on the pressure fluid to be transported during the stroke. As a result, the pressurized fluid may suddenly exit the cylinder space 6. As the mass of Kim 10 is raised, the pressurized fluid has more time to exit from the interior 2 of the piston rod 1 and inner tube 3 to the return line.

The variable pressure fluid inside the inner tube 3 also effectively cools the compressed gas in the cylinder space 4.

Figure 2 shows the impact device of Figure 1 positioned at the right end of the body tube 19.

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The body tube 19 also acts as a guide member for the impact mass 10 as the impact mass slides within the body 19 of the body 30 as it is raised and accelerated by the impact device. For impact mass 10

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o is Movement space 12. Impact mass 10 strikes piece 13. The entire impact device is connected from the part 11 secured to the frame tube S 17, for example, to the end of the excavator boom while working on it.

The opening of the valve 15 shown in Figure 1 adjusts the length of the pulp uplift.

Claims (6)

An impact medium operating on a pressurized medium, such as a hydraulic fluid pressure fluid 5, comprising an elongated body (19) for attachment to a machine, a movable impact mass (10) mounted on the body (19) having a linear guide member mounted on said body (19) 10) for lifting up for impact, comprising a first cylinder (20) and a piston (16) movable therewith by a pressurized fluid and a piston rod (1), the arrangement having said piston rod (1) secured to said 10 masses and a valve assembly (15) , by which the pressure of the hydraulic fluid can be applied to the first cylinder (20) on the other side of the piston (16) for lifting the pulp (10), and said pressure can be abruptly reduced by directing the pulp (10) 20) the hydraulic fluid returning from the cylinder space (6) or a part thereof by a valve assembly (15) by guiding-15 into the expanding space (2) inside the piston rod (1), thereby substantially reducing the adverse back pressure caused by the hydraulic fluid exiting the piston (16). Impact device according to Claim 1, characterized in that the piston rod (1) of the first cylinder (20) is hollow, whereby it is adapted to pass over the inner tube (3) and the inner space (2) of the inner tube (3) and the piston rod (1). ), the inner space (2) functions as an expanding space capable of receiving hydraulic fluid supplied to the return line at a rate of strokes and during the lifting of the mass (10) the movement of the piston rod (1) removes hydraulic fluid from said interior (2) to the unpressurized return line of the hydraulic system. Impact device according to claim 1, characterized in that the valve assembly o (15) is adapted to open a passage for the pressure fluid from the inner space (2) of the piston rod (1) and inner tube (3) to the return line of the hydraulic system. to open the passage for the hydraulic fluid returning along the tube (14) to said interior space (2) £ as the pulp (10) is accelerated to impact. ; 30 Impact device according to claim 1, characterized in that the annular space (5), the blade space (4) of the cylinder 5 and the inner tube (3) are coaxial to each other. Impact device according to claim 1, characterized in that a constant volume volume (5) communicating via a duck (17) is connected to the part (4) of the cylinder space filled with the gas in the first cylinder (20). Impact device according to claim 5, characterized in that the constant space (5) connected by the apertures (17) is formed as an annular space around the first cylinder (20). 10