FI78857B - SLAGANORDNING DRIVEN AV EN VAETSKA UNDER TRYCK. - Google Patents

Abstract

1. A percussion apparatus moved by a pressurised fluid, of the type comprising a mobile striking mass (2) in the form of a piston supplying a series of impacts on a tool (3), this piston being slidably mounted in a cylinder (4) which, provided in the body (5) of the apparatus and including ports (6, 7) connected by ducts (8, 9), serves additionally in the sliding of a distributor (10) connecting the chamber (11) situated above the piston alternately to a high pressure circuit (12), for enabling the piston to descend rapidly, and to a low pressure circuit (13) for effecting the return strocke of this piston, characterised in that it comprises, on the one hand, a non-return valve (22) enabling fluid to pass from the chamber (11) located above the strike piston towards the high pressure circuit (12) and, on the other hand, means ensuring that the distributor (10) is displaced sequentially in such a way that, starting from a position in which the chamber (11) located above the piston is connected to the high pressure (12), the distributor is displaced very rapidly as far as a position in which it interrupts the connection between the said chamber and the high pressure, then at a lower, controlled speed, so as to delay the connecting of the chamber (11) to the low pressure circuit (13), so as to enable the maximum amount of restorative energy to be recovered for the entire duration of the isolation of the chamber located above the piston with respect to the high pressure and low pressure circuits, by compressing the fluid isolated in the chamber for the passage of the latter into the high pressure circuit by means of the non-return valve.

Description

1 78857

Impactor operated by a fluid under pressure

The present invention relates to an impact device driven by a pressurized fluid, such as an incompressible hydraulic fluid.

This device produces a series of impacts on the tool via an impacting, moving mass in the form of a piston. The piston is slidably mounted on a cylinder which, arranged in the body of the device 10 and comprising openings connected to the channels, further acts as a guide for a distributor which alternately connects a high pressure circuit for rapid piston lowering and a low pressure circuit for piston shock recovery.

In the embodiment shown in the drawing, the divider is pushed by a spring in the direction of the tool according to FR patent publication 1431835.

However, this device could be presented in different forms, for example the distributor would not be moved by a spring but by pushers used by hydraulic pressure according to FR patent publication 2045289 or it could be moved by a recessed piston in the middle of two opposite arms according to FR patent publication 2369908.

25 The operation of this type of device, whatever the mode of operation of the distributor, has its roots in the basic technique of contacting the chamber above the piston alternately with high and low pressure while keeping the small and opposite annular parts 30 at high pressure so that the hydraulic forces are directed one direction and the other.

Examination of the operation of this device shows that the kinetic energy stored in the high velocity percussion piston at the moment of impact is converted into a tool 2 78857 by a compression wave passing through the tool at the speed of sound in metal and then converted into a force capable of breaking it. In fact, only a fraction of this energy is absorbed into the rock as the rest of the pa-5 is loaded into the tool in the form of a compression wave coming back towards the device.

This rearward flushing wave is either damped in the body of the device via the tool collar or returned to the piston in the form of kinetic energy. In this house case, the piston bounces back and compresses the fluid towards the low pressure circuit in the form of a hydraulic pressure wave, commonly referred to in hydraulic equipment as a fluid shock.

In both cases, the return energy is not only helplessly lost but also causes detrimental impulses to the good condition of the material and in particular rapid wear of the contact collars between the tool and the body, fatigue of low pressure flexible parts due to adaptive low pressure or another 20 due to return energy loss.

It should also be noted that as the blast wave returning to the tool returns to the piston in the form of kinetic energy, the piston becomes assisted in the return stroke and the operating parameters change in the direction of decreasing high pressure relative to rock hardness, this pressure reduction detrimental to device efficiency.

The object of the invention is to enable the energy 30 contained in the pressing wave returning to the tool to be recovered for its subsequent reuse.

This object is achieved by an impact device characterized in that it comprises a non-return valve through which the pressurized fluid can pass from the chamber above the piston to the high-35 pressure circuit and 3 78857 means for controlling the distributor to move at high speed from the chamber communication position. to a high-pressure circuit, a position where the connection between the chamber and the high-pressure circuit is lost, after which it continues to move at a low, controlled speed so as to delay the connection between the chamber and the low-pressure circuit. The energy contained in the fluid compressed into the -10 mio is recovered as the pressurized fluid passes through the non-return valve to the high pressure circuit.

This arrangement offers a number of significant advantages, namely: 15 - low wear of the tool support collar; - better maintenance of low-pressure flexible parts, because at this level liquid shocks fade; - the given flow provides an increase in the impact frequency, since all the recovered liquid 20 can be utilized in addition to the liquid produced in the device. This increase in stroke frequency corresponds to a shortening of the duration of each operating cycle and results in a change in operating parameters in the opposite direction to before, i.e. high pressure, i.e. the efficiency of each stroke relative to the hardness of the rock 25 in the direction of increase; - a reduction in the heating, which is usually due to the attenuation of the energy of the return wave, which is favorable for the good temporal maintenance of the organs of the device; - this improvement in operating conditions also makes it possible to reduce the intensity of the recoil and the vibrations on the support of the device.

Preferably, the time taken by the divider to transition between closing the connection between the chamber above the piston and the high pressure circuit and communicating this same chamber with the low pressure circuit is equal to ------ - I __________ 4 78857 than the time required for even the most significant known recovery from the hardest rocks.

This feature allows for maximum energy recovery whatever the nature of the material to be broken by this impactor.

According to another feature of the invention, the distributor experiences a new acceleration movement as soon as the chamber above the piston communicates with the low pressure circuit so that this opening is widely released and allows the free movement of the moving impact mass.

According to an embodiment of the invention, the divider consists of two parts with different cross-sections, namely a part on the piston side corresponding to the cross-section of the cylinder greater than the cross-sectional area of the large cross-sectional portion of the distributor, the large cross-sectional portion of this distributor 20 penetrating a cubic chamber arranged therebetween the cylinder and the widened cavity at the the annular volume limited by the connection of the two parts of the chamber and the divider in communication with the chamber above the piston for at least one dimensioned leakage opening.

30 When the large cross-sectional part or collar of the distributor is located in the cavity above the cylinder, the distributor is not subjected to any braking and moves rapidly in the direction of the piston.

When the edge 35 corresponding to the connection of the two parts of the distributor closes the annular chamber, it causes the latter 5 78857 to compress the liquid contained therein, manifesting as a sharp braking of the movement of the distributor. From this point on, the movement of the distributor can only continue with the exit of the liquid through the dimensioned opening. The cross-sectional area of the latter thus depends on the speed at which the divider moves between the position at which it ensures separation of the chamber above the piston from the high-pressure circuit and the position at which it makes the chamber in contact with the low-pressure circuit.

10 According to the first possibility, a dimensioned opening for the removal of fluid from the annular chamber is arranged in a wall delimiting this chamber from the outside.

Alternatively, the manifold is provided with an axial channel, the extreme end of which, when opened into a rim connecting the zones of the different parts of the manifold, forms a dimensioned opening, ensuring the removal of fluid outside the annular chamber.

The invention will be well understood in all respects by means of the following description with reference to the accompanying schematic drawings, which show, by way of limitation, many embodiments of the device according to the invention:

Figures 1-5 show five longitudinal sections of a first embodiment of this device during five operating steps;

Fig. 6 is a partial sectional view taken along line 6-6 of Fig. 1 of a cavity in which the top of the divider is mounted;

Figure 7 shows a section of a modification of the cavity of Figure 6;

Fig. 8 is a sectional view of a portion of the device showing a modification of the arrangement for discharging liquid from the annular chamber;

Figures 9, 10 and 11 show a part of the device in section, showing three embodiments of a non-return valve located between the chamber above the percussion piston and the high pressure circuit 6 78857;

Figure 12 shows a longitudinal section of a modification of the embodiment of the device of Figures 1-5; Fig. 13 shows a diagram of the displacement of the divider as a function of time;

Figures 14 and 15 show two longitudinal sections on an enlarged scale of a part containing the device divider of Figures 1-5 as two times of operation;

Figures 16 and 17 show two longitudinal sections on an enlarged scale of the part containing the divider of Figure 8 during the two operating steps.

The divider 10 consists of two different cross-sectional parts 15, namely a lower part 16 inserted into the upper end of the cylinder 4, the diameter of which corresponds to the diameter of the cylinder 4 in which the percussion piston 2 moves and a larger-beveled upper part 17. This part 17 is located in a cavity 18 20 cross section than part 17.

In the embodiment shown in Fig. 6, the increase in the cross-sectional area of the cavity 18 relative to the divider portion 17 is provided by arranging a lateral crescent-shaped cavity, while in Fig. 7 the cavity 18 comprises two cavity-opposite cavities 25 each.

However, the manifold portion 17 may penetrate its corresponding cross-sectional chamber 19 as the chamber 19 extends the cylinder 4. The dimensions of the chamber 19 and the widened portion or collar 17 of the manifold are such that the manifold ensures closure of the passageway between the high pressure circuit 12 and the piston chamber 11, the collar 17 arrives at the level of the chamber 19 and intends to block it.

The connection between the annular chamber 19 and the cavity 18 is now ensured only by a dimensioned opening 20.

Il 7 78857

A non-return valve, indicated by reference numeral 22, is provided between the cavity 18 connected to the chamber 11 and the high pressure circuit 12, which will be described later.

5 The operation of this device is as follows:

In the first time interval, as shown in Fig. 1, the divider 10 moves very rapidly from the position where the high pressure entry takes place towards the high pressure circuit closing position corresponding to Fig. 2. This lie corresponds to the shift (d0, dl) during the diagram period (t0, t1) of Fig. 13. This rapid displacement is made possible by the fact that the two sides of the manifold collar 17 are in hydraulic communication with the large channels at the level of the cavity 18. The connecting edge 23 of the zones of the different parts of the Kim distributor arrives at the level of the chamber 19 and will clog it, a certain volume of liquid is compressed in said chamber, whereby the continuation of the movement of the distributor can only be achieved by discharging the liquid through the dimensioned opening 20. By changing the cross-sectional area of the orifice 20, it is possible to control the transfer time of the divider by the positions it has in Figures 2 and 4, the two positions corresponding to closing the high pressure circuit and opening the low pressure column 13, respectively.

This time interval of the transition, during which the chamber 11 is simultaneously isolated from the high-pressure nozzle 12 and the low-pressure nozzle 13, allows, as shown in Fig. 3, the maximum recovery of return energy from the chamber 11 towards the high-pressure circuit 12 and more towards the accumulator 24. via a check valve 22. This step corresponds to the transfer (d1, d2) of the divider during the period (t1, t2) of the diagram of Fig. 13.

When the return energy recovery is complete, the divider continues its journey down to the position shown in Figure 5. The chamber 11 above the piston is brought in contact with the low pressure circuit as-35

_____ - I

8 via 78857 channels 7.9 allowing the impact piston 2 to return, ensuring the discharge of the liquid contained in this chamber. This step manifests itself as a divider shift (d2, d3), which is shown in the diagram of Figure 13.

Figure 8 shows a variant of introducing the annular chamber 19 into the liquid discharge. In this case, a channel 25 is arranged axially in the divider, the channel opening in a rim 23 connecting the different zones of the divider. The channel 25 has the same effect on the liquid discharge 10 as the dimensioned opening 20.

According to the first possibility, shown in Figures 1-5 and 8, the non-return valve 22 returns to its base thanks to a central chamber 26 located below the valve head, which is connected to the low-pressure circuit via the channel 29.

In the embodiment shown in Figure 9, the non-return valve 22 returns to its base due to the annular chamber 27 provided by the difference between the two diameters 28a and 28b, which is connected to the low pressure circuit via the channel 29.

In the embodiment shown in Fig. 10, the valve 22 is maintained in the closed position by a vacuum between the high pressure circuit 12 and the chamber 11 as soon as the fluid flow direction is about to reverse, because the valve rise 25 is limited by a small clearance J detent 30.

In the embodiment shown in Fig. 11, the non-return valve 22 returns to its closed position by a spring 32 which rests on the one hand on the valve and on the other hand on a stop 33 located on the side of the high pressure circuit.

Fig. 12 shows a modification of the embodiment of the device of Figs. 1-5, in which the divider 10 is no longer under the influence of a spring 14, but of a central plunger 34 with two opposite piston rods. In this case, it is not possible to think of the valve 35 return arrangement shown in Fig. 8, but one of the arrangements shown in Figs. 9-11 may be considered.

9 78857

In the embodiment shown in Figures 14 and 15, the divider has a throat 35 arranged between the two cylindrical parts 16 and 17. The cylinder 4 body is further provided with at least one wide dimensioned channel 36, 5 which opens into the cavity where the cylindrical part 16 slides. is further positioned to contact the annular volume provided by the throat 35 and the low pressure circuit as soon as the station of the divider 10 prepares the connection of the chamber 11 to the low pressure circuit. This allows a new acceleration of the distributor's movement.

In the embodiment shown in Figures 16 and 17, the discharge of liquid outside the chamber 18 is carried out in a channel 25 as in the case shown in Figure 8. The throat 37 is arranged on the periphery of the chamber 19 and the channel 38 is arranged on the divider, being able to bring the chamber 19 into wide contact with the low pressure circuit as soon as the divider 10 ensures that the chamber 11 is connected to the low pressure circuit.

As will be apparent from the foregoing, the invention provides a major improvement over the prior art by providing an impact device which is not more complex in construction than conventional devices and which has higher performance and reliability than the latter.

Claims (8)

A stroke device driven by a fluid under pressure comprising movable, brazing, mass (2) in the form of a piston 5 which produces a series of blows on a tool (3), the piston being slidably mounted in a body of the device (5). arranged cylinder (4) with openings (6.7) connected to channels (8,9) and which acts as a guide for the distributor (10) which puts a stay of a high pressure circuit (11) above a co-located chamber (11) 12), which allows a rapid drop of the coif, and a low pressure circuit (13), which enables the stroke of the piston, characterized in that it comprises a non-return valve (22), through which the liquid under pressure can pass from the chamber located above the coif ( 11) to the high-pressure circuit (12) and means, which control the movement of the distributor (10), so that it moves at a high speed before a rack, where the chamber (11) is a blind to the high-pressure circuit (12), to a position where the connection between the chamber (11) and the high-pressure circuit (12) is broken, after which it continues to move at a low, regulated speed, so that the establishment of a blind between the chamber (11) and the low pressure circuit (13) is delayed, whereby the above-chamber (11) is isolated from both the high pressure circuit (12) and the low pressure circuit (13), a fluid compressed by the chamber (11) caused by the compressed air fluid. The contained energy is collected when the liquid is pressurized through the check valve (22) to the high pressure circuit (12). Device according to claim 1, characterized in that the gap between the breaking of the fuse between the above-coil chamber (11) and the high-pressure circuit (12) establishing the fuse between this chamber (11) and the low-pressure circuit (13) is equal to a tent necessary for the most significant hard rock species dependent on the study. i4 78857 Impact device according to Claim 1 or 2, characterized in that the distributor (10) undergoes a new acceleration movement immediately when the chamber (11) located above the coif is in contact with the low pressure circuit (13), so that this opening is closed. to a large extent and allows free movement of the striking, moving mass (2). Stroke device according to any one of claims 1-3, characterized in that the distributor (10) consists of two parts with different cross-sectional surfaces, namely a piston-side part (16), whose cross-sectional surface corresponds to the cross-section of the cylinder (4), and of a larger cross-sectional surface (17) located on the other side, which portion (17) is mounted in a heel cavity (18), which forms an extension of the barrel and has a larger cross-sectional area than the large cross-sectional area portion (17) , which portion (17) is arranged to penetrate a chamber (19) of the same cross-sectional area disposed between the cylinder (4) and the extended heel space (18), the penetration of the chambers (19) beginning when the distributor reaches a position in which the connection between the chamber above (11) and the high-pressure circuit (12) is broken, whereby an annular space defined by the chamber (19) and both parts (16,17) of the distributor (10) connection with the chamber (11) located above the coif or at least one opening (20). 5. Impact device according to claim 4, characterized in that the opening (20) through which the liquid can be extruded from the annular space (19) is arranged in an outer wall defining the chamber (19). Stroke device according to any of claims 3-5, characterized in that the distributor (10) has a throat (35) arranged between the two cylindrical parts of different Large cross sections (16,17), and that at least one channel (36) opens into the cylinder (4) to insert the annular space defined by the throat (35)