EP0300929B1 - Hydraulic distributing device for percussion apparatus - Google Patents

Abstract

In the body of the distributor (6) is mounted for sliding a valve (21) delimiting with the bore of the distributor in which it is mounted at least one control chamber (22) in permanent communication by means of at least one channel (31) with the control chamber of the distributor. When a hydraulic signal is received in the control chambers, the valve (21) moves, controlling the subsequent movement of the distributor (6) independently of any hydraulic connection made by the percussion piston.

Description

The present invention relates to a hydraulic distributor for percussion device driven by an incompressible fluid under pressure, supplied in such a way that the result of the hydraulic forces, applying to the striking piston, either alternately in one direction or in the other.

Document US-A-1 904 694 relates to a distribution device for a pneumatic hammer comprising two valves, or distributors, mounted concentrically, the respective sequential movements of which are completely independent.

Let us consider for example, an apparatus comprising a stepped piston sliding in a body and delimiting with its bores a driving chamber subjected alternately, by means of a distributor, to the pressure prevailing in the supply circuit having a high pressure accumulator, and to the return pressure of the device, and an opposing annular chamber constantly connected to the supply pressure.

The distributor is actuated hydraulically according to the position of the striking piston, for example by providing a control section which is, depending on the position of the striking piston, subjected alternately to the supply pressure of the device. or that of the return circuit.

Also consider that when the supply pressure. applies to the control section of the distributor, the driving chamber of the impact piston is subjected to this same pressure and that the piston is then accelerated during its impact stroke and that, conversely, when the pressure of the return circuit applies on the distributor control section, the driving chamber of the striking piston is connected to the return circuit of the device and the piston travels its return stroke.

It is understood that one could design a hydraulically controlled distribution system which would operate in reverse.

For implementation reasons, it is known that it is necessary to maintain the distributor hydraulically in each position at the ends of its stroke during the time which separates the control pressure information supplied by the striking piston and that it is also necessary to allow the distributor to systematically browse and completely its course, in order to switch the circuits correctly; in summary, the distributor must be "bi-stable".

This double function can, for example, be carried out in a known manner by providing calibrated orifices in the body of the dispenser. which allow either to supply pressurized fluid, or to drain towards the return circuit, the control chamber of the distributor.

But, for reasons of practical achievements, these orifices, which cannot simultaneously and constantly be connected to the control chamber so as not to cancel their respective actions, are only effective during part of the stroke of the dispenser.

It is therefore imperative that the communications established by the striking piston, during its movement, between the distributor control circuit and alternately the supply circuit and the return circuit of the device, be maintained for a sufficient time to ensure the movement of the dispenser until the locking hole opens.

The relative movements of the striking piston and the distributor are of great importance. The accelerations and speeds of movement of the distributor as a function of the movement of the impact piston as well as the hydraulic control point of the distributor by the piston during its descent must be chosen carefully.

The main difficulties encountered arise during the stroke of the piston. Indeed, it is known for example from French patent 2,509,217 that the kinetic energy supplied by the impact piston to the tool at the time of the impact is partially transmitted to the rock and that the balance can be returned in return under form of kinetic energy at the piston.

In this case, the piston rebounds and remains for a very short time in the vicinity of the tool. However, as indicated above, the connection made by the striking piston between the distributor control circuit and the return circuit, in this case, must necessarily last long enough to allow the distributor to perform the part of its stroke which allows it reach the locking hole of the next phase of the cycle.

As the speed of the piston when approaching the tool is high, the hydraulic switching effected by the piston must therefore occur fairly early in its downward stroke to ensure that in the event of a rebound, it lasts long enough. Indeed, if the control point is close to the moment of the end of the piston's downward stroke, the communication time, established by the latter is insufficient for the distributor to have had time, during its stroke, to reverse the action of its locking holes, the distributor will then only cover an insufficient part of its stroke and will return to the starting point, remaining on the locking of the previous phase of the cycle, it will then maintain the driving chamber of the piston at the pressure of the high-pressure supply circuit, which will have the consequence of re-accelerating the piston after its rebound and over a short stroke, a second very weak shock may occur, considerably disturbing the operating cycle of the device.

Conversely, if the control point of the distributor is located too early during the downward stroke of the piston, the distributor risks prematurely traversing its reversal stroke and therefore, switching the driving chamber of the piston too soon towards low pressure.

This chamber is no longer supplied with pressurized fluid, the piston will therefore no longer be accelerated during the end of its stroke, resulting in a significant loss of efficiency and the formation of a vacuum in the motor chamber with risk of cavitation s 'there is a rebound phenomenon.

Of course, in the case of a percussion device working with a constant stroke, a constant pressure and therefore a constant acceleration, it is known that one can find a compromise and determine an ideal point of control of the dispenser during the lowering of the piston, the various operating parameters being fixed.

On the other hand, for a device equipped with a stroke variation or pressure variation system having a fixed distributor control point, the speed of descent of the piston near the impact varies in great proportions, the time which takes between the moment of order and the shock therefore also varies a lot. It then becomes impossible to find a compromise for the position of the distributor control point, the latter correct for a high piston speed will be premature for a lower speed, correct for a low piston speed, it will be too late for a speed bigger.

The present invention seeks to remedy these drawbacks by providing a hydraulic distributor which satisfactorily controls the movement of the striking piston for percussion frequencies which are liable to vary significantly, for example between 300 and 1000 blows per minute.

• dans le corps du distributeur est monté coulissant un tiroir dont la masse est inférieure à celle du distributeur, délimitant, avec l'alésage du distributeur dans lequel il est monté, au moins une chambre de commande en communication permanente par au moins un canal ménagé dans le corps du distributeur avec la chambre de commande du distributeur elle-même reliée successivement par un circuit ménagé dans le corps de l'appareil au circuit haute pression et au circuit basse pression en fonction de la position du piston,
• la forme du tiroir et des chambres qu'il délimite avec l'alésage du distributeur dans lequel il est monté, sont telles que la résultante des forces auxquelles il est soumis le déplace alternativement dans un sens et dans l'autre suivant que la chambre de commande est reliée à la haute ou à la basse pression,
• dans le tiroir est ménagé un circuit dont une extrémité débouche en permanence dans la chambre de commande du tiroir et dont l'autre extrémité débouche dans un évidement qui permet une mise en communication de ce circuit, par l'intermédiaire d'orifices calibrés et, suivant la position du tiroir, avec la haute pression ou avec la basse pression, le maintien en fluide sous pression par l'orifice calibré étant consécutif à une mise en communication des chambres de commande avec le circuit haute pression en fonction de la position du piston, le maintien à la basse pression par l'orifice calibré étant consécutif à une mise en communication des chambres de commande avec le circuit basse pression en fonction de la position du piston.

To this end, the distributor it concerns, of the type comprising a piston driven by an alternating movement during which it strikes a tool, the distributor comprising a sliding body in a working cylinder with the bore of which it delimits in particular a control chamber successively connected to the high pressure circuit and to the low pressure circuit , depending on the position of the striking piston, thus putting the driving chamber located at the end of the piston successively in communication with the high pressure circuit to allow the accelerated descent of the piston and with the low pressure circuit to allow the return stroke of this piston, is characterized in that:

• in the body of the distributor is slidably mounted a drawer whose mass is less than that of the distributor, delimiting, with the bore of the distributor in which it is mounted, at least one control chamber in permanent communication by at least one channel formed in the body of the distributor with the control chamber of the distributor itself connected successively by a circuit formed in the body of the device to the high pressure circuit and to the low pressure circuit as a function of the position of the piston,
• the shape of the drawer and of the chambers which it delimits with the bore of the distributor in which it is mounted, are such that the result of the forces to which it is subjected moves it alternately in one direction and in the other depending on whether the control is connected to high or low pressure,
• a circuit is formed in the drawer, one end of which opens permanently into the control chamber of the drawer and the other end of which opens into a recess which allows this circuit to be placed in communication, by means of calibrated orifices, and depending on the position of the slide valve, with high pressure or with low pressure, the maintenance of pressurized fluid by the calibrated orifice being consecutive to placing the control chambers in communication with the high pressure circuit as a function of the position of the piston , maintaining at low pressure through the calibrated orifice being consecutive to placing the control chambers in communication with the low pressure circuit as a function of the position of the piston.

Advantageously, the drawer is mounted coaxially in the body of the dispenser.

When the striking piston provides hydraulic information to the control chambers of the drawer and the distributor, the drawer changes instantly from position due to its low inertia, this movement necessarily causing the displacement of the distributor, whatever the duration of the hydraulic connection produced by the striking piston with the control chamber thereof.

• Figures 1 à 4 sont quatre vues en coupe longitudinale d'un appareil équipé d'un premier distributeur au cours de cinq phases de fonctionnement ;
• Figure 5 est une vue en coupe longitudinale d'une variante du distribueur de figures 1 à 4 ;
• Figures 6 à 10 sont cinq vues en coupe longitudinale d'un appareil équipé d'un autre distributeur au cours de cinq phases de fonctionnement ;
• Figures 11 à 15 sont cinq vues correspondant à celles des figures 6 à 10, représentant un appareil équipé d'un autre distributeur.

Anyway, the invention will be well understood with the aid of the description which follows, with reference to the appended schematic drawing, representing, by way of nonlimiting examples, several embodiments of this device:

• Figures 1 to 4 are four views in longitudinal section of an apparatus equipped with a first distributor during five operating phases;
• Figure 5 is a longitudinal sectional view of a variant of the dispenser of Figures 1 to 4;
• Figures 6 to 10 are five views in longitudinal section of an apparatus equipped with another distributor during five operating phases;
• Figures 11 to 15 are five views corresponding to those of Figures 6 to 10, showing an apparatus equipped with another distributor.

The assembly of FIGS. 1 to 10 represents a percussion device operating according to a known principle, comprising a piston 1 sliding in a body 2 . The striking piston 1 delimits with its bore the driving chamber 3 , located above the piston, and an annular chamber 7 of small surface, antagonistic to the chamber 3 . The chamber 7 is constantly in relation to the high pressure through the channel 8 . The reciprocating movement of the piston is obtained by putting the motor chamber 3 in communication alternately with the high pressure supply circuit 4 and the low pressure return circuit 5 , so that the result of the hydraulic forces is exerted alternately one way and the other. This communication of the chamber 3 alternately with the high pressure and the low pressure is carried out by the distributor 6 , according to the hydraulic means described below.

In the embodiment shown in the drawing, the distributor 6 delimits with its bores four chambers 9, 10, 11, 12 . The chamber 9 and the annular chamber 10 are connected to each other by wide channels 13 formed in the body of the distributor 6 , they are constantly subjected to the supply pressure, the channel 4 opening directly into the chamber 9 . The chamber 11 of small section is antagonistic to the chamber 10 and is constantly connected to the low pressure circuit 5 . Finally, chamber 12 , the surface of section 15 of which is greater than that of chamber 11 , called the control chamber, is antagonistic to chambers 9 and 11 .

The choice of the surfaces of the sections of the chambers 9 and 12 is such that, when the control chamber 12 is brought to the high supply pressure of the apparatus, the distributor 6 assumes the position of the FIG. 3 and then places the high pressure supply circuit in communication with the driving chamber 3 via the chamber 9 , the channels 13 , the chamber 10 and the channel 14 so as to accelerate the piston in its stroke. hit. Conversely, when the control section 15 is connected to a low pressure circuit, the distributor 6 occupies the position shown in Figure 1 and connects the chamber 3 with the return circuit of the device 5 and thus allows the piston to rise. hits 1 .

The choice of the stroke of the piston 1 is carried out according to a known principle by means of a drawer 16 installed sliding in the body of the device 2 . This drawer, which can, for example, be remote-controlled as described in French Patent No. 2,375,008, selects a control channel from a series of channels 17 and 20 opening into the cylinder, the selected channel being able to be connected to the supply circuit. in pressurized fluid once discovered by the edge 47 of the striking piston.

By way of nonlimiting example and for the following description, it is accepted that the distributor 6 is driven in a downward movement when the control chamber 12 is connected to the return circuit and in an upward movement when this the latter communicates with the supply circuit.

In the device shown in FIGS. 1 to 4, the invention consists in providing, sliding in the body of the distributor 6 , a stepped drawer 21 which delimits with its bores a control chamber 22 , an antagonistic annular chamber 23 , constantly connected to the supply pressure through the channels 24 and 13 , formed in the body of the distributor 6 and a chamber 25 antagonistic to the chamber 22 permanently connected to the return circuit 5 by the channel 26 formed in the body of the distributor 6 . Depending on the pressure exerted in the control chamber 22 , the result of the hydraulic forces is exerted alternately in one direction or the other.

The drawer 21 further comprises a groove 27 , delimited by two edges 28 and 29 , connected directly to the control chamber 22 by a channel 30 formed in the body of the drawer.

The control chambers of the distributor 6 and of the stepped drawer 21 are constantly connected by a channel 31 .

In the body of the distributor 6 are formed two orifices calibrated 32 and 33 being able to allow alternately and depending on the position of the slide 21 a communication between the groove 27 and the chamber 10 constantly connected to high pressure or between the groove 27 and the groove 34 formed in the body of the device, it- even constantly connected to the return circuit by channel 35 .

The operation of this device is as follows:
FIG. 1 represents the position of the distributor 6 and of the drawer 21 while the piston 1 rises and is about to discover the channel 19 selected by the drawer 16 .

The control chambers 12 and 22 are, at this instant, connected to the return circuit of the apparatus 5 via the channel 30 , the groove 27 , the orifice 33 , the chamber 34 and the channel 35 .

The distributor, at this instant, puts the channel 14 and therefore the chamber 3 into communication with the return circuit 5 , thereby allowing the piston 1 to travel up , the orifice 33 and the stepped drawer 21 then ensuring the connection to the low circuit return pressure from the control chambers.

As soon as the edge of the piston 47 , delimiting one end of the chamber 7 , discovers the channel 19 , a large quantity of pressurized fluid can circulate in the channels 19 and 36 and supply the control chambers 12 and 22 . A small quantity of pressurized feed fluid will then circulate through the orifice 33 calibrated so that the pressure established in the groove 27 and therefore in the chambers 12 and 22 is sufficient to modify the direction of the results. hydraulic which are exerted, respectively, on the slide 21 and the distributor 6 .

The slide 21 , with a mass much lower than that of the distributor 6 , will move quickly (as shown in FIG. 2), the edge 29 will then close the orifice 33 , while, simultaneously, the edge 28 will discover the orifice 32 . The groove 27 is then connected to the supply circuit by the orifice 32 , thus ensuring a second source of supply of pressurized fluid to the control chambers 12 and 22 .

Continuing its upward movement, the distributor 6 will interrupt the connection of the channel 14 with the return circuit of the device 5 , then establish communication between the supply circuit 4 and the motor chamber 3 , the pressurized fluid circulating at through chamber 9 , channels 13 , chamber 10 and channel 14 , the striking piston 1 begins its downhill course and the edge 47 closes the channel 19 . This closure does not interrupt the upward movement of the distributor since the second supply of high pressure oil to the chamber 12 via the channels 30, 31, 32 (FIG. 3) has taken over from the initial supply via the channels 19 and 36 .

FIG. 3 represents the position of the distributor 6 and of the drawer 21 , while the striking piston 1 is accelerated in its striking stroke and is about to discover the channel 17 .

The chambers 12 and 22 are, at this instant, connected as described above to the supply circuit by the calibrated orifice 32 , the groove 27 and the channel 30 .

The distributor 6 also ensures communication between the supply circuit 4 and the channel 14 connected to the motor chamber 3 .

It has been seen previously that the piston 1 is accelerated in its stroke. Shortly before the impact, the edge 37 delimiting the lower end of the groove 38 formed in the piston 1 discovers the channel 17 . The groove 38 then ensures the connection between the channel 17 and the return circuit of the device 5 via a channel 39 formed in the body of the device and opening into the bearing surface 75 of the cylinder used for the displacement of the piston .

The chambers 12 and 22 are then connected by a circuit widely open to the low pressure return circuit by the channels 36, 17 and 39. The quantity of fluid liable to circulate through the calibrated orifice 32 at the supply pressure is then insufficient to create the pressure necessary to balance the distributor 6 and the drawer 21 . The results of the hydraulic forces applied to the distributor and to the drawer 21 are reversed.

The drawer 21 with a mass much lower than that of the distributor 6 will therefore move quickly downwards (as shown in FIG. 4). The edge 28 will then close the orifice 32 and simultaneously the edge 29 will discover one end of the orifice 33 , the other end constantly opening into the groove 34 , the groove 27 will from this moment be connected to the return circuit of the device 5 through the calibrated orifice 33 , creating a second circuit for emptying the chamber 12 towards the return circuit 5 allowing, in this way, the movement of the distributor 6 downwards, even in the event of rebound up the piston on the tool prematurely closes the channel 17 , by the edge 37 .

Continuing its downward movement, the distributor 6 interrupts the connection of channel 14 with the power supply to the device, then establishes communication between the return circuit 5 and the chamber 3 via channel 14 , the piston 1 can then run its ascent race.

FIG. 5 shows a variant of the hydraulic distribution device shown in FIGS. 1 to 4. In this case, the slide 21 delimits with its bore two opposing chambers, one permanently connected to the return circuit and comprising a return spring 40 , the other being the control chamber 22 alternately connected to the supply pressure and to the return pressure of the device. In this drawer, are formed a groove 27 and a channel 30 which perform the same functions as above.

The movement of the slide is obtained, in this case, by setting the supply pressure to the control circuit, then by the action of the return spring when the control chamber 22 is subjected to the back pressure of the device. .

It can be very advantageous, during the downward movement of the dispenser, to quickly close the supply of pressurized fluid to chamber 3 and slowly open the drain circuit of this same chamber, in order to avoid phenomena of "water hammer" in the pipes.

The rise of the distributor must on the other hand be rapid at the time of the supply of pressurized fluid to limit the pressure drops. On the other hand, it can be very useful to lock the drawer (21) during the movement of the dispenser to make it insensitive to possible pressure fluctuations, its very rapid movement when climbing can be braked at the end of the stroke in order to avoid a shock in the body of the dispenser. Finally, a DASH POT® type system can slow down the upward end of travel of the dispenser.

Such a device is shown in Figures 6 to 10 of the drawing.

The drawer 21 delimits with its bores a control chamber 22 , an opposing annular chamber 23 and another opposing chamber 25 . At the end of the stroke, the drawer defines a buffer chamber 41 as soon as the edge 42 of the drawer 21 coincides with the edge 43 delimiting the end on the distributor side of the chamber 41 . Room 41 is constantly connected to channel 26 via a channel 44 in which is mounted a calibrated orifice 76 , formed in the body of the dispenser.

The chamber 23 is connected to the supply pressure when the distributor 6 is at the end of the up or down stroke, by means of a channel 45 formed in the body of the distributor brought into contact in the low position (FIG. 6) with the groove 70 , itself connected to the high pressure of the chamber 10 by the channel 72 and in the high position (FIG. 9) directly to the high pressure of the chamber 10 . The edges 51 and 73 , respectively delimiting the bottom of the chamber 10 and an edge of the groove 70 , determine the instant of locking of the chamber 23 by the closing of the channel 45 during movements of the dispenser 6 .

The chamber 25 is constantly connected to the low pressure circuit 5 by the channel 26 .

The control chamber 22 , as before, is constantly connected to the control chamber 12 of the distributor by the channel 31 formed in the body of the distributor 6 .

As before, a groove 27 delimited by two edges 28 and 29 is formed in the body of the drawer 21 , a second groove 52 is also formed in the drawer 21 , delimited at the upper end by the edge 53 , the two grooves 27 and 52 are constantly connected to each other and to the control chamber 22 by the channel 54 formed in the body of the drawer 21 .

The distributor 6 defines with its bores, during its course, six separate chambers. The opposite chambers 9 and 10 described above, constantly connected to each other by the channels 13 , the chamber 12 or control chamber alternately connected to the high pressure supply circuit 4 or to the low pressure return circuit 5 , the annular chamber 11 constantly connected in the low pressure return circuit 5 , an annular chamber 55 permanently in the supply circuit (for example, it is here connected to the chamber 10 ) by a channel 56 in which is mounted a calibrated orifice 57 formed in the body of the device, distributor side this chamber is delimited by the edge 58 , finally an annular buffer chamber 59 , delimited by an edge 60 on the distributor side and an edge 61 on the body side of the device, which is created when the edge 62 of the distributor coincides or exceeds the edge 61 , this chamber 59 is always connected to the supply circuit by a channel 63 comprising a calibrated orifice 64 formed in the body of the device.

In the body of the distributor are still three other important channels. The channel 65 , one end of which opens into the range of the cylinder used to guide the distributor and the other into the range of the distributor used to guide the drawer 21 , which can, depending on the relative positions of the distributor 6 and of the drawer 21 , be isolated or link throat 34 and throat 27 . Channels 66 and 67 , one end of which respectively opens into the range of the distributor serving to guide the drawer 21 and the other into the range of the distributor serving to guide it into the body of the device. The channel 66 may, depending on the position of the slide 21 , either be isolated, or successively be in communication with the groove 52 and the channel 54 , then with the channel 67 via the groove 52 .

Finally, in the body of the device are formed two grooves. The groove 34 , delimited by two edges 68 and 69 , permanently connected to the return circuit by the channel 35 . The groove 70 delimited by the edges 71 and 73 and constantly connected by a channel 72 to the supply circuit. By way of example, channel 72 opens into chamber 10 .

• La chambre 59 est intégrée à la chambre 9 et entièrement soumise à la pression d'alimentation.
• La chambre 23 est reliée à la haute pression de la chambre 10 par le canal 45, la gorge 70 et le canal 72.
• La chambre 41 fait partie intégrante de la chambre 25.
• Les canaux 67 et 66 sont obturés par le tiroir 21.
• L'orifice calibré 32 est obturé à la fois par le corps de l'appareil 2 et le tiroir étagé 21.
• L'orifice calibré 33 relie la gorge 34 et la gorge 27 et par conséquence, la chambre de commande 12 au circuit basse pression 5 par les canaux 31, 54 et 35.
• Le canal 65 est obturé par la portée du cylindre assurant le guidage du distributeur.
• Le canal 14 est relié au circuit retour 5 par le distributeur, le piston 1 remonte (selon figure 1).

The operation of the device is as follows:
Figure 6 shows the position of the distribution assembly while the striking piston 1 goes up. The relative positions of the distributor 6 with respect to the body of the device and of the drawer 21 , with respect to the body of the distributor are such that:

• The chamber 59 is integrated into the chamber 9 and entirely subjected to the supply pressure.
• The chamber 23 is connected to the high pressure of the chamber 10 by the channel 45 , the groove 70 and the channel 72 .
• Room 41 is an integral part of room 25 .
• The channels 67 and 66 are closed by the drawer 21 .
• The calibrated orifice 32 is closed at the same time by the body of the device 2 and the stepped drawer 21 .
• The calibrated orifice 33 connects the groove 34 and the groove 27 and, consequently, the control chamber 12 to the low pressure circuit 5 by the channels 31, 54 and 35 .
• The channel 65 is closed by the bearing of the cylinder ensuring the guiding of the dispenser.
• The channel 14 is connected to the return circuit 5 by the distributor, the piston 1 goes back up (according to FIG. 1).

As soon as the edge 47 of the piston discovers the channel 20, 19, 18 or 17 selected by the regulating slide 16 , a large quantity of pressurized fluid can circulate through the control channel 36 .

The pressure being established in the chambers 12 and 22 by the circulation of the supply fluid through the calibrated orifice 33 is such that the slide 21 and the distributor 6 are unbalanced and begin their movements upwards.

The drawer 21 being of mass much less than that of the distributor 6 , it will therefore move quickly. During its movement, the oil contained in the chamber 23 will be discharged through the channel 45 , the groove 70 and the channel 72 . The edge 29 of the groove 27 closes the channel 65 then the calibrated orifice 33 , simultaneously the edge 28 discovers the calibrated orifice 32 .

The edge 53 of the groove 52 successively uncovers the channel 66 , thus allowing a complementary supply of the chamber 55 with pressurized fluid coming from the control circuit 36 via the channels 31 and 54 , then one end of the channel 67 , the other end remaining partially closed by the scope of the distributor in the body 2 . Finally, when the slide 21 has traveled a large part of its travel, the edge 42 crosses the edge 43 , the chamber 41 is then isolated from the chamber 25 and the oil it contains will have to circulate through the channel 44 and the calibrated orifice 76 so as to create sufficient pressure to slow down the slide 21 , thus avoiding any violent impact at the end of the stroke. We will say that the drawer 21 is provided with a DASH POT® type system.

At this time, the distribution assembly is in the position in FIG. 7.

• L'arête 73 obture le canal 45, verrouillant ainsi la chambre 23 et en conséquence, le tiroir 21 dans sa position haute.
• L'arête 74 de la chambre 55 découvre l'orifice calibré 32 qui relie alors la chambre 55 à la gorge 27.
• L'arête 71 de la gorge 70 découvre le canal 67 relié alors à la gorge 52 et donc, par l'intermédiaire des canaux 72, 66, 54 et 31, les chambres 55, 22 et 12 sont soumises à la haute pression du circuit d'alimentation (figure 8).

Simultaneously and with a lower acceleration, the distributor 6 moves upwards. During its race:

• The edge 73 closes the channel 45 , thus locking the chamber 23 and consequently, the drawer 21 in its high position.
• The edge 74 of the chamber 55 discovers the calibrated orifice 32 which then connects the chamber 55 to the groove 27 .
• The edge 71 of the groove 70 discovers the channel 67 then connected at the groove 52 and therefore, via the channels 72, 66, 54 and 31 , the chambers 55, 22 and 12 are subjected to the high pressure of the supply circuit (FIG. 8).

• Simultanément, le distributeur 6 obture le canal 14 et le relie ensuite au circuit d'alimentation 4, le piston 1 peut alors amorcer sa course de descente en son arête 47 referme le circuit de commande sélectionné. A partir de cet instant, le fluide sous pression nécessaire au mouvement du distributeur circule à travers les canaux 56, 72, 67, 66, 54 et 31.
• L'arête 62 du distributeur croise ensuite l'arête 61, le fluide contenu dans la chambre 59 doit alors circuler à travers l'orifice calibré 64, la pression qui est alors créée dans la chambre 59 freine le distributeur puis régule sa vitesse finale.
• En fin de course, l'arête 51 de la chambre 10 découvre le canal 45 et déverrouille ainsi la chambre 23.
• L'arête 73 recouvre le canal 67 puis le canal 66, la fin du mouvement du distributeur et son verrouillage en position haute sont alors assurés par l'huile sous pression qui circule à travers les canaux 72 et 56 puis l'orifice calibré 32.
• L'arête 69 découvre le canal 65.

It should be noted that, as soon as the calibrated orifice 32 is opened, the supply of pressurized fluid to the control circuit is ensured, the fluid flowing through the channel 56 , the groove 55 , the orifice 32 , the groove 27 and channel 54 .

• Simultaneously, the distributor 6 closes the channel 14 and then connects it to the supply circuit 4 , the piston 1 can then start its downward movement at its edge 47 closes the selected control circuit. From this moment, the pressurized fluid necessary for the movement of the distributor circulates through the channels 56, 72, 67, 66, 54 and 31 .
• The edge 62 of the distributor then crosses the edge 61 , the fluid contained in the chamber 59 must then flow through the calibrated orifice 64 , the pressure which is then created in the chamber 59 brakes the distributor then regulates its final speed.
• At the end of the race, the edge 51 of the chamber 10 discovers the channel 45 and thus unlocks the chamber 23 .
• The edge 73 covers the channel 67 then the channel 66 , the end of the movement of the distributor and its locking in the high position are then ensured by the pressurized oil which circulates through the channels 72 and 56 then the calibrated orifice 32 .
• The edge 69 discovers the channel 65 .

The distribution assembly is then in the configuration shown in FIG. 9.

Shortly before the impact, as described above, the edge 37 discovers the channel 17 which is then connected to the low pressure return circuit 5 , the control circuit comprising the channel 36 , the chambers 12, 22 and the grooves 27 and 52 is then also connected to the return circuit of the device.

The quantity of fluid which can circulate through the calibrated nozzle 32 at the supply pressure being insufficient to maintain an equilibrium pressure in the aforementioned control circuit, the slide 21 and the distributor 6 begin their downward movements. The slide 21 with a mass much lower than that of the distributor 6 moves rapidly, during its movement, the pressurized fluid circulates through the channel 45 and feeds the chamber 23 , the edge 53 of the groove 52 closes the channels 67 and 66 , the edge 28 closes the calibrated orifice 32 , the edge 29 discovers the calibrated orifice 33 , then the channel 65 which then establishes a significant passage between the control chambers 12 and 22 and the return circuit 5 of the device, via the groove 34 and the channel 35 . From this moment, the edge 37 of the piston 1 can cover the channel 17 without influencing the movement of the dispenser.

The distribution assembly is shown diagrammatically at this time in FIG. 10.

• L'arête 51 de la chambre 10 obture le canal 45 et verrouille ainsi la chambre 23.
• Le fluide sous pression contenu dans la chambre 55 s'évacue par le canal 72 jusqu'à ce que l'arête 58 croise l'arête 71, à partir de cet instant, le fluide va devoir circuler à travers l'orifice calibré 57 et la pression créée dans la chambre 55 va tout d'abord freiner le distributeur puis réguler sa vitesse.
• Le distributeur 6 interrompt la liaison entre le canal 14 et le circuit d'alimentation, puis met en communication le circuit retour de l'appareil 5 et le canal 14, le piston 1 peut alors remonter sous l'effet des forces hydrauliques.
• L'arête 68 découvre l'orifice 33 et l'arête 74 de la chambre 55 recouvre l'orifice calibré 32.
• En fin de course, l'arête 71 obture le canal 67, l'arête 69 obture le canal 65, le verrouillage et la fin de course sont alors assurés par l'orifice calibré 33 qui maintient alors le circuit de commande à la pression retour de l'appareil.
• L'arête 73 découvre le canal 45 et déverrouille la chambre 23 du tiroir 21 qui pourra ainsi réagir à la prochaine impulsion de commande.

Simultaneously and with less acceleration, the distributor begins its downhill course. During its movement:

• The edge 51 of the chamber 10 closes the channel 45 and thus locks the chamber 23 .
• The pressurized fluid contained in the chamber 55 is evacuated through the channel 72 until the edge 58 crosses the edge 71 , from this moment, the fluid will have to circulate through the calibrated orifice 57 and the pressure created in the chamber 55 will first brake the distributor and then regulate its speed.
• The distributor 6 interrupts the connection between the channel 14 and the supply circuit, then puts in communication the return circuit of the device 5 and the channel 14 , the piston 1 can then rise under the effect of hydraulic forces.
• The edge 68 discovers the orifice 33 and the edge 74 of the chamber 55 covers the calibrated orifice 32 .
• At the end of the stroke, the edge 71 closes the channel 67 , the edge 69 closes the channel 65 , the locking and the end of travel are then ensured by the calibrated orifice 33 which then maintains the control circuit at the return pressure. of the device.
• The edge 73 discovers the channel 45 and unlocks the chamber 23 of the drawer 21 which can thus react to the next command pulse.

The distribution assembly then occupies the positions described in FIG. 6.

The piston 1 completes its ascent stroke and the described cycle can resume.

The device, shown in Figures 11 to 15 of the drawing, is a variant of that described above in Figures 6 to 10 which allows to adjust the speed of rise of the distributor during part of its stroke as a function of the quantity of pressurized fluid which circulates through the control channel 36 .

It is thus possible to vary the time which elapses between the moment when the distributor begins to move and that when it will open the supply of pressurized fluid to chamber 3 .

Consequently, the time of ascent of the impact piston and therefore its stroke vary simultaneously.

The stroke of the striking piston 1 can therefore be modified simply by controlling the quantity of pressurized fluid which can circulate through an orifice of variable section 78 located on the channel 20 . A passage of small section will correspond to a long stroke and, conversely, an orifice of large section to a short stroke.

Of course, this device can also operate with a stroke selection drawer 16 as described above, the possibility of adjusting the rise time of the distributor is then not used.

In this configuration, the chamber 55 is no longer constantly connected to the supply circuit by the channel 56 which includes the calibrated orifice 57 . By cons, it is formed in the body of the distributor 6 , an orifice 77 which can allow, depending on the position of the slide 21 , communication between the chamber 55 and the control circuit 36 via the groove 52 , the channel 54 , chamber 22 , channel 31 and control chamber 12 .

The edge 79 constitutes the lower end of the groove 52 .

• La chambre 59 est intégrée à la chambre 9 et entièrement soumise à la pression d'alimentation.
• La chambre 23 est reliée à la haute pression de la chambre 10 par le canal 45, la gorge 70 et le canal 72.
• La chambre 41 fait partie intégrante de la chambre 25.
• Les canaux 67 et 66 sont obturés par le tiroir 21.
• L'orifice calibré 32 est obturé à la fois par le corps de l'appareil 2 et le tiroir étagé 21.
• L'orifice calibré 33 relie la gorge 34 et la gorge 27 et, par conséquent, la chambre de commande 12 au circuit basse pression 5 par les canaux 31, 54 et 35.
• Le canal 65 est obturé par la portée du cylindre assurant le guidage du distributeur.
• Le canal 14 est relié au circuit retour 5 par le distributeur, le piston 1 remonte (selon figure 11).
• L'orifice calibré 77 relie la chambre 55 au circuit de commande 36 par l'intermédiaire de la gorge 52 et des canaux 54 et 31.

The operation of the device is as follows:
Figure 11 shows the position of the distribution assembly, while the striking piston 1 goes up. The relative positions of the distributor 6 with respect to the body of the device and of the drawer 21 , with respect to the body of the distributor are such that:

• The chamber 59 is integrated into the chamber 9 and entirely subjected to the supply pressure.
• The chamber 23 is connected to the high pressure of the chamber 10 by the channel 45 , the groove 70 and the channel 72 .
• Room 41 is an integral part of room 25 .
• The channels 67 and 66 are closed by the drawer 21 .
• The calibrated orifice 32 is closed at the same time by the body of the device 2 and the stepped drawer 21 .
• The calibrated orifice 33 connects the groove 34 and the groove 27 and, consequently, the control chamber 12 to the low pressure circuit 5 by the channels 31, 54 and 35 .
• The channel 65 is closed by the bearing of the cylinder ensuring the guiding of the dispenser.
• The channel 14 is connected to the return circuit 5 by the distributor, the piston 1 goes back up (according to FIG. 11).
• The calibrated orifice 77 connects the chamber 55 to the control circuit 36 via the groove 52 and the channels 54 and 31 .

As soon as the edge 47 of the striking piston 1 discovers the channel 20 , pressurized fluid circulates through the variable orifice 78 and the control channel 36 .

In the case of normal operation, the pressure which builds up in the chambers 12 and 22 circulation of the supply fluid through the variable orifice 78 and the calibrated orifice 33 is sufficient to unbalance the drawer 21 and the distributor. 6 and therefore start their movements upwards. Otherwise, it will be necessary to wait until the edge 47 of the piston 1 discovers the channel 17 , in order to allow a large quantity of fluid under pressure to flow through the control channel 36 , this case corresponds to the maximum stroke of the piston and constitutes a safety device if the minimum section of the variable orifice 78 is adjusted too small.

The drawer 21 being of mass much less than that of the distributor 6 , it will therefore move quickly. During its movement, the oil contained in the chamber 23 will be discharged through the channel 45 , the groove 70 and the channel 72 . The edge 29 of the groove 27 closes the channel 65 then the calibrated orifice 33 , simultaneously the edge 28 discovers the calibrated orifice 32 .

The edge 79 of the groove 52 closes one end of the calibrated orifice 77 .

The edge 53 of the groove 52 successively uncovers the channel 66 , allowing the supply of the chamber 55 with pressurized fluid coming from the control circuit 36 via the channels 31, 54 and the variable orifice 78 then a end of channel 67 , the other end remaining partially closed by the range of the distributor in the body 2 . Finally, when the slide 21 has traveled a large part of its travel, the edge 42 crosses the edge 43 , the chamber 41 is then isolated from the chamber 25 and the oil it contains will have to circulate through the channel 44 and the calibrated orifice 76 , so as to create sufficient pressure to slow down the drawer 21 , thus avoiding any violent shock at the end of the race . We will say that the drawer 21 is provided with a DASH POT type system.

At this time, the distribution assembly is in the position in FIG. 12.

• L'arête 73 obture le canal 45, verrouillant ainsi la chambre 23 et, en conséquence, le tiroir 21 dans sa position haute.
• L'arête 74 de la chambre 55 découvre l'orifice calibré 32 qui relie alors la chambre 55 à la gorge 27.
• L'arête 71 de la gorge 70 découvre le canal 67 relié alors à la gorge 52 et donc, par l'intermédiaire des canaux 72, 66, 54 et 31, les chambres 55, 22 et 12 sont soumises à la haute pression du circuit d'alimentation (figure 13). A partir de cet instant, le déplacement du distributeur devient indépendant de la section de l'orifice 78.
• Simultanément, le distributeur 6 obture le canal 14 et le relie ensuite au circuit d'alimentation 4, le piston 1 peut alors amorcer sa course de descente et son arête 47 referme le circuit de commande sélectionné. A partir de cet instant, le fluide sous pression nécessaire au mouvement du distributeur circule à travers les canaux 72, 67, 66, 54 et 31.
• L'arête 62 du distributeur croise ensuite l'arête 61, le fluide contenu dans la chambre 59 doit alors circuler à travers l'orifice calibré 64, la pression qui est alors créée dans la chambre 59 freine le distributeur puis régule sa vitesse finale.
• En fin de course, l'arrêt 51 de la chambre 10 découvre le canal 45 et déverrouille ainsi la chambre 23.
• L'arête 73 recouvre le canal 67 puis le canal 66, la fin du mouvement du distributeur et son verrouillage en position haute sont alors assurés par l'huile sous pression qui circule à travers le canal 72, puis l'orifice calibré 32.
• L'arête 69 découvre le canal 65.

Simultaneously and with a lower acceleration, the distributor 6 moves upwards. Its displacement speed then depends on the quality of pressurized fluid which circulates through the variable orifice 78 and which supplies the chambers 12 and 55 .

• The edge 73 closes the channel 45 , thus locking the chamber 23 and, consequently, the drawer 21 in its high position.
• The edge 74 of the chamber 55 discovers the calibrated orifice 32 which then connects the chamber 55 to the groove 27 .
• The edge 71 of the groove 70 discovers the channel 67 then connected to the groove 52 and therefore, via the channels 72, 66, 54 and 31 , the chambers 55, 22 and 12 are subjected to the high pressure of the circuit power supply (Figure 13). From this moment, the displacement of the distributor becomes independent of the section of the orifice 78 .
• Simultaneously, the distributor 6 closes the channel 14 and then connects it to the supply circuit 4 , the piston 1 can then initiate its downward stroke and its edge 47 closes the selected control circuit. From this moment, the pressurized fluid necessary for the movement of the distributor circulates through the channels 72, 67, 66, 54 and 31 .
• The edge 62 of the distributor then crosses the edge 61 , the fluid contained in the chamber 59 must then flow through the calibrated orifice 64 , the pressure which is then created in the chamber 59 brakes the distributor then regulates its final speed.
• At the end of the race, the stop 51 of the chamber 10 discovers the channel 45 and thus unlocks the chamber 23 .
• The edge 73 covers the channel 67 then the channel 66 , the end of the movement of the distributor and its locking in the high position are then ensured by the pressurized oil which circulates through the channel 72 , then the calibrated orifice 32 .
• The edge 69 discovers the channel 65 .

The distribution assembly is then in the configuration shown in FIG. 14.

Shortly before the impact, as described above, the edge 37 discovers the channel 17 which is then connected to the low pressure return circuit 5 , the control circuit comprising the channel 36 , the chambers 12, 22 and the grooves 27, 52 is then also connected to the return circuit of the device.

The quantity of fluid which can circulate through the calibrated nozzle 32 at the supply pressure being insufficient to maintain an equilibrium pressure in the aforementioned control circuit, the slide 21 and the distributor 6 begin their downward movements. The slide 21 with a mass much lower than that of the distributor 6 moves rapidly, during its movement, the pressurized fluid circulates through the channel 45 and feeds the chamber 23 , the edge 53 of the groove 52 closes the channels 67 and 66 , the edge 79 of the groove 52 discovers the calibrated orifice 77 , the edge 28 closes the calibrated orifice 32 , the edge 29 discovers the calibrated orifice 33 , then the channel 65 which then establishes an important passage between the control chambers 12 and 22 and the return circuit 5 of the device, via the groove 34 and the channel 35 . From this moment, the edge 37 of the piston 1 can cover the channel 17 without influencing the movement of the dispenser.

The distribution assembly is shown diagrammatically at this time in FIG. 15.

• L'arête 51 de la chambre 10 obture le canal 45 et verrouille ainsi la chambre 23.
• Le fluide sous pression contenu dans la chambre 55 s'évacue par le canal 72 jusqu'à ce que l'arête 58 croise l'arête 71, à partir de cet instant, le fluide va devoir circuler à travers l'orifice calibré 77, la gorge 52, le canal 54, la gorge 27 et le canal 65. La pression créée dans la chambre 55 va tout d'abord freiner le distributeur, puis réguler sa vitesse.
• Le distributeur 6 interrompt la liaison entre le canal 14 et le circuit d'alimentation, puis met en communication le circuit retour de l'appareil 5 et le canal 14, le piston 1 peut alors remonter sous l'effet des forces hydrauliques.
• L'arête 68 découvre l'orifice 33 et l'arête 74 de la chambre 55 recouvre l'orifice calibré 32.
• En fin de course, l'arête 71 obture le canal 67, l'arête 69 obture la canal 65, le verrouillage et la fin de course sont alors assurés par l'orifice calibré 33 qui maintient alors le circuit de commande à la pression retour de l'appareil.
• L'arête 73 découvre le canal 45 et déverrouille la chambre 23 du tiroir 21 qui pourra ainsi réagir à la prochaine impulsion de commande.

Simultaneously and with less acceleration, the distributor begins its downhill course. During its movement:

• The edge 51 of the chamber 10 closes the channel 45 and thus locks the chamber 23 .
• The pressurized fluid contained in the chamber 55 is evacuated through the channel 72 until the edge 58 crosses the edge 71 , from this instant, the fluid will have to circulate through the calibrated orifice 77 , groove 52 , channel 54 , groove 27 and channel 65 . The pressure created in the chamber 55 will first brake the distributor, then regulate its speed.
• The distributor 6 interrupts the connection between the channel 14 and the supply circuit, then puts in communication the return circuit of the device 5 and the channel 14 , the piston 1 can then rise under the effect of hydraulic forces.
• The edge 68 discovers the orifice 33 and the edge 74 of the chamber 55 covers the calibrated orifice 32 .
• At the end of the stroke, the edge 71 closes the channel 67 , the edge 69 closes the channel 65 , the locking and the end of travel are then ensured by the calibrated orifice 33 which then maintains the control circuit at the return pressure. of the device.
• The edge 73 discovers the channel 45 and unlocks the chamber 23 of the drawer 21 which can thus react to the next command pulse.

The distribution assembly then occupies the positions described in FIG. 11.

Position 1 completes its ascent stroke and the described cycle can resume.

Claims (16)

1. A hydraulic distributor for a percussion apparatus actuated by a non-compressible fluid under pressure and including a piston (1) driven in a reciprocating movement during which it strikes a tool, the distributor including a body (6) sliding in a working cylinder with the bore of which it particularly delimits a control chamber (12) successively connected to the high pressure circuit (4) and to the low pressure circuit (5), as a function of the position of the impact piston (1), thus placing the driving chamber (3) located at the end of the piston successively in communication with the high pressure circuit (4) to allow the accelerated descent of the piston (1) and with the low pressure circuit (5) to allow the return travel of this piston, characterised in that:

   - in the body of the distributor (6) is slidable mounted a slide (21) of which the mass is less than that of the distributor (6) delimiting, with the bore of the distributor in which it is mounted, at least one control chamber (22) in permanent communication through at least one passage (31) formed in the distributor body (6) with the control chamber (12) of the distributor itself successively connected by a circuit formed in the body of the apparatus to the high pressure circuit (4) and to the low pressure circuit (5) as a function of the position of the piston (1),

   - the shape of the slide (21) and of the chambers which it delimits with the bore of the distributor in which it is mounted, are such that the resultant of the forces to which it is subjected moves it alternately in one direction and in the other depending upon whether the control chamber (22) is connected to the high or to the low pressure,

   - in the slide (21) is formed a circuit (30), of which one end opens permanently into the control chamber (22) of the slide and of which the other end opens into a cavity (27) which allows this circuit (30) to be placed in communication, by means of calibrated orifices (32) and (33), depending on the position of the slide (21), with the high pressure or with the low pressure, the maintenance of fluid under pressure through the calibrated orifice (32) resulting from the control chambers (12, 22) being placed in communication with the high pressure circuit as a function of the position of the piston, the maintenance of the low pressure through the calibrated orifice (33) resulting from the control chambers (12, 22) being placed in communication with the low pressure circuit as a function of the position of the piston.
2. A distributor according to Claim 1, characterised in that the slide (21) is slidably mounted coaxially within the body (6).
3. A distributor according to any one of Claims 1 and 2, characterised in that the control chambers (12, 22) respectively of the distributor body (6) and of the slide (21) are disposed on the same side at the corresponding ends of these two elements, and in that the body (6) of the distributor and the slide (21) move in the same direction when the control chambers are successively placed in communication respectively with the high pressure and low pressure circuits.
4. A distributor according to any one of Claims 1 to 3, characterised in that the slide (21) delimits, with the bore of the distributor body (6) in which it is slidably mounted, three chambers of which the sectional surfaces are such that the resultant of the hydraulic forces is applied alternately in one direction and in the other:
      a control chamber (22) permanently connected to the control chamber (12) of the distributor through a passage (31), and

   - two chambers (23, 25) opposed to the first, of which the one (23) is permanently connected to the high pressure circuit and the other (25) is permanently connected to the low pressure circuit.
5. A distributor according to any one of Claims 1 to 3, characterised in that the slide (21) delimits, with the bore of the distributor body (6) in which it is slidably mounted, two opposing chambers:

   - a control chamber (22) permanently connected to the control chamber (12) of the distributor through a passage (31), and

   - a chamber permanently connected to the low pressure circuit and equipped with a spring (40) acting on the slide in the direction of the chamber (22), such that the resultant of the hydraulic and mechanical forces is exerted alternately in one direction and in the other.
6. A distributor according to any one of Claims 1 to 5, characterised in that in the slide (21) is formed a throat (27) permanently connected to the control chamber (22), and which can alternately uncover calibrated orifices (32, 33) opening into the bearing surface of the distributor body (6) serving to guide the slide (21), these orifices communicating respectively with the high pressure circuit (4) and with the low pressure circuit (5).
7. A distributor according to any one of Claims 1 to 3, characterised in that the slide (21) delimits with the bore of the distributor body (6) in which it is slidably mounted, a chamber (41) which, disposed at the end opposite to the control chamber (22), communicates through a calibrated orifice (76) with the low pressure circuit, whilst the body (6) delimits at the upper end of travel a chamber (59) with the bore in which it is slidably mounted which communicates through a calibrated orifice (64) with the high pressure circuit, means being provided which ensure the locking, within the distributor body of the slide (21) after movement thereof and before corresponding movement of the distributor body.
8. A distributor according to Claim 7, characterised in that the slide (21) delimits with the bore of the distributor body in which it is slidably mounted:

   - a control chamber (22) permanently connected to the control chamber (12) of the distributor through a passage (31), and

   - two opposing chambers (25, 23) of which the one (25) is permanently connected to the low pressure circuit and the other (23) is connected to the high pressure circuit for the two end of travel positions of the distributor body and is isolated from the circuit for the intermediate positions thereof, thus effecting the locking of the slide.
9. A distributor according to Claim 8, characterised in that the slide (21) has a second throat (52) in permanent communication with the throat (27) and the control chamber (22), and able, during its movement in translation, to uncover orifices (66, 67) formed in the distributor body, these orifices (66, 67) being intended to be placed in communication with the control circuit (12, 31, 22, 54, 52) then with the high pressure circuit (4) during the movement of the distributor body (6) between a position in which it ensures the placing in communication of the chamber (3) located at the piston head side with the low pressure circuit (5) and a position in which it ensures the placing in communication of this same chamber (3) with the high pressure circuit (4).
10. A distributor according to any one of Claims 7 to 9, characterised in that in the body (6) is formed a supplementary orifice (65) of large size intended to place the control chambers (12, 22) in communication with the low pressure circuit when the body of the distributor is in an extreme position corresponding to the placing in communication of the chamber (3) with the high pressure circuit (4), and in that the slide (21) is in a position in which its control chamber (22) has a minimum volume.
11. A distributor according to Claims 7 to 10 taken together, characterised in that its control means are arranged in such a manner that, starting from a position in which the chamber (3) located above the piston is in communication with the low pressure circuit (5), when the control chambers (12, 22) are connected to the high pressure circuit (4) by the passage of the impact piston (1) to a determined point in its travel, the slide (21) moves rapidly, then slowly finishes its travel when the chamber (41) is closed, simultaneously and at a slower speed, the distributor body (6) moves, isolates the chamber (23) from the slide (21) by closing the passage (45), cuts the communication between the chamber (3) and the low pressure circuit (5) and places this chamber in communication with the high pressure circuit (4), the distributor body slowing at the end of its travel when the chamber (59) closes, with the placing in communication of the chamber (23) of the slide with the high pressure circuit then, as soon as the impact piston (1) switches the control pressure, the slide (21) rapidly covers its return travel placing the control chambers (12, 22) freely in communication through the orifice (65) with the low pressure circuit, the distributor body (6), whilst, at the beginning of its travel, isolating the chamber (23) from the slide, moves rapidly to a position in which it isolates the chamber (3) located above the piston (1) from the high pressure circuit (4), then more slowly until this chamber is placed in communication with the low pressure circuit (5), and finally returns the chamber (23) into communication with the high pressure circuit (4) and closes the passage (65) which connects the chamber (27) of the slide with the low pressure circuit (5).
12. A distributor according to any one of Claims 7 to 10, characterised in that in the body (2) is formed a passage (56) connected to the supply circuit (4) and provided with an orifice (57) intended to regulate the draining of an annular chamber (55) permanently connected to the supply circuit and thus the speed of the distributor (6) during its descending movement between a position in which this latter closes off the communication of the chamber (3) located on the piston head side with the high pressure circuit (4) and a position in which it ensures the progressive placing in communication of this same chamber (3) with the low pressure circuit (5).
13. A distributor according to any one of Claims 7 to 10, characterised in that in the slide (21) is formed a throat (52) permanently connected to the control chamber (22), and which can uncover and close off an orifice (77) opening into the bearing surface of the distributor body (6) serving to guide the slide (21), this orifice (77) communicating with the annular chamber (55).
14. A distributor according to Claims 7, 8, 9, 10, 11 and 13 taken together, characterised in that its control means are arranged such that, starting from a position in which the chamber (3) located above the piston is in communication with the low pressure circuit (5), when the control chambers (12, 22) are connected to the high pressure circuit (4) by passage of the impact piston (1) to a determined point on its travel, the slide (21) moves rapidly and closes off the orifice (77), simultaneously and at a slower speed regulated by the amount of fluid able to circulate in the control circuit (20), (36), the distributor body (6) moves, cuts the communication between the chamber (3) and the low pressure circuit (5), then accelerates, as soon as the passages (66) and (67) freely connect the control circuit (12, 31, 22, 54, 52) with the supply circuit (4), and place the chamber (3) in communication with the high pressure circuit (4), as soon as the impact piston (1) switches the control pressure, the slide (21) rapidly effects its return travel and uncovers the orifice (77), the distributor body (6) moves rapidly to a position in which it isolates the chamber (3) from the high pressure circuit (4), then more slowly until this chamber is placed in communication with the low pressure circuit (5) as soon as the edge (71) crosses the edge (58), the fluid contained in the chamber (55) having to flow through the orifice (77) and the control circuit (52), (54), (27), (33), (65) to reach the return circuit (5).
15. A distributor according to Claim 14, characterised in that the speed of movement of the distributor body (6) is regulated by the quantity of fluid under pressure able to circulate through an orifice (78) of variable section located in the passage (20) which supplies the control circuit (36, 12, 31, 22, 54, 77, 55) when this same passage is connected to the high pressure circuit by passage of the impact piston (1) to a determined point in its upward return travel.
16. A distributor according to Claim 15, characterised in that its control means are arranged such that the travel of the impact piston (1) can be varied as a function of the section of the variable orifice (78) to modify the displacement time of the distributor (6) during its upward travel.

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