DE2334711A1 - ROCKER ARM MACHINE BRAKE DEVICE FOR USE IN AN COMBUSTION MACHINE - Google Patents

Description

Dr.E. Wtogind, DIpJ. Ing.W. Nleminn Ir. M. Krtler. Dipl.-Ing. C. Bernhardt

Patent attorneys

Hamburg 50 - KönigsiraOe 28

W.25788 / 73 12 / Sch

23-3471 T

The Jacobs Manufacturing Company West Hartford, Connecticut (V.St.A.)

Rocker arm engine braking device for use in an internal combustion engine.

The invention relates to rocker arm machine braking devices, provided in an internal combustion engine, the devices being of a type with v / elcher the exhaust valve of a piston cylinder is not is kept open only during the usual time in the piston circuit by cam action, but also to a time near the end of a compression stroke so that compressed gases are released from the cylinder and as a result the energy is consumed that would otherwise be applied to the pistons

Devices of this general type are known (U.S. Patents 3,367,312 and 3,332,405). In these known devices acts the usual acting from the camshaft cam via a rocker arm to the exhaust valve in the Open the machine circuit at the usual time. To open the exhaust valve near the end of the compression

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Cause stroke, if it is desired to retard the speed of the machine, an ^M game ⁿ piston in the rocker arm can be hydraulically actuated as desired by the operator in order to absorb the play usually present between the rocker arm and the exhaust valve in such a way that an auxiliary cam the camshaft can act via the rocker arm to open the exhaust valve.

The purpose of the invention is to provide a device with a play piston to create that has an improved hydraulic design for actuating the play piston.

A feature of the invention resides in the manner in which the rocker arm shaft is used to supply crankcase oil for general lubrication purposes and for operating the play piston.

Another feature of the invention resides in the design and arrangement of the passages for the supply of the hydraulic working medium such that undesired air bubbles are released from the device.

The invention is explained below with reference to the drawing, for example.

Pig. 1 is a plan view of a sectional view of a Rocker arm shaft of an internal combustion diesel engine on which the invention is embodied. Pig. 2 is a sectional view taken along line 2-2 of FIG. 1 looking toward a solenoid valve controller; which is arranged in a support frame of the rocker arm shaft. Pig. 3 is an enlarged scale Partial view of the pig. 2, in which the moved position of the solenoid valve after energization of the Solenoid is shown.

Pig. Figure 4 is a sectional view taken along line 4-4 of Pig. 1, in which the position of an exhaust rocker arm to the exhaust valves of one of the cylinders of the engine is shown.

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Fig. 5 is an enlarged scale Partial view in which the trailing end of the valve rod or push rod according to FIG. 4-in Assignment to a cam element is shown, which is from the camshaft of the machine is worn.

Fig. 6 is a "held in an enlarged scale fragmentary view of the rocker arm according to FIG. 4, with portions cut away. Fig. 7 is a sectional view taken along line 7-7 ^ ^he Fig. 6, in which the normal position of the combined AC and check valve device is shown.

Fig. 8 is a fragmentary view, on an enlarged scale, showing the moving state of the in Fig. 7 combined change and check valve device is shown. FIG. 9 is a view corresponding to FIG. 6 of a modified embodiment of the invention, where g'edoch the design of the changeover and check valves in the hydraulic system shown as separate elements. 10 is a sectional view taken along line 10-10 of FIG ^ ig · 9 »in softer the design and arrangement the changeover and check valves are shown. ·

FIG. 11 is a view corresponding to FIG. 4 of an embodiment of the invention in which the Rocker arm above a single exhaust valve.

In Figs. 1 to 8 is an embodiment of the invention shown in a diesel internal combustion engine, specifically in association with one of the cylinders 10 of the machine (Fig. 4-). The piston 11 working in the cylinder 10 is a four-stroke piston. Only as much is described of the machine as it is

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is necessary for understanding the invention. Accordingly, no description will be given of the conventional fuel injection device and air intake devices associated with the cylinder.

The cylinder has two exhaust valves 12, which are usually closed by conventional valve springs 13 are kept as it is in Pig. 4 is shown. A bridge 14 actuating the exhaust valves spans the The tappet 15 of both valves 12 and can be actuated by an overhead rocker arm 16 to open the valves 12 to push in the open position. The bridge 14 is slidably supported on a shaft 17 in the cylinder head 18 is anchored in such a way that the bridge 14 can perform axial sliding movement relative to the valves 12.

The rocker arm 16 is arranged pivotably between its ends on a stationary rocker arm shaft 21 which is carried by a bearing or holding device 22 (FIG. 1) which is bolted to the top of the cylinder head 18 is. One end of the rocker arm 16 is arranged over the central region of the bridge or the web 14, and a opposite end is above a valve pushrod 24. The rocker arm 16 can be of the pushrod 24 relative to the Bridge 14 is pivoted when a rotating cam element 25 (FIG. 5) cooperates with the push rod 24 will. The bumper 24 is provided with a trailing part 26 which runs on the circumference of the cam element 25. The cam element 25 is carried by the conventional camshaft 27. The camshaft 27 is driving in the usual way connected to the usual crankshaft of the machine.

The cam element 25 has a main elevation 28 its circumference, which cooperate with the bumper 24 at the usual time in the circuit of the piston 11 can to open the exhaust valves 12. Furthermore, on the circumference of the cam element 25 at an angular distance from the

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Elevation 28 an auxiliary elevation or secondary elevation 29 is provided, the radial extent of which is smaller than that radial extension of the main elevation 28 is. This auxiliary survey 29 can work with the bumper 24 to move the rocker arm 16 / at a time near the end of the The compression stroke of the piston 11 relative to the bridge 14 to pivot. The auxiliary elevation 29 of the cam 25 is obtained by undercutting or undercutting the base circle of the cam element 25, as it is by the broken line 30 is indicated. The time control the cooperation of the respective cam elevations 28, 29 with the bumper 24 is determined by the angular position which is given to the cam elevations 28, 29 relative to one another, and by the angular arrangement of the cam element 25 on the camshaft 27

Usually the cooperating is the auxiliary cam elevation 29 with the bumper 24 ineffective to move the bridge 14 to open the exhaust valves 12 cause, namely due to the usual small play, which between the rocker arm 16 and the bridge 14 is present. If desired, the working condition of the machine from the normal drive state to the braking state to convert, it is intended to take up the play in the rocker arm 16, so that the exhaust valves 12 be opened by the action of the auxiliary cam elevation 29 at or near the end of the compression stroke, so that the driving energy of the compressed gases from the cylinder is released. To achieve this, a so-called backlash piston 31 (Fig. 4, 6 and 7) is in a bore 32 of the Rocker arm 16 is provided. It is arranged and designed in such a way that it can be actuated by the operator if necessary can be such that it is in the direction of the rocker arm 16 in pressure relationship or pressure position to the valve bridge 14 moves so that the game in the rocker arm 16 is taken up.

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The play piston 31 is arranged in the rocker arm 16 above the central region of the valve bridge 14. It is usually held against the bottom of its bore 32 by the biasing force of a return spring 33. the Spring 33 has a U-shape (FIG. 7) and it has a bridge part 34 which is attached to the underside of a projection of the rocker arm 16 is attached, as well as two parallel spring legs 35 · One of the legs 35 extends via a flat on one side of an outwardly protruding part of the piston 31, and the other leg extends over a similar flat area on the opposite side of the piston 31. The spring legs 35 exert a pretensioning force on shoulders 37 which are arranged overhead and which are formed by the flattened areas of the piston 31 and this force usually causes the piston 31 to sit in its bore 32.

The play piston 31 can at the discretion of the operator in the direction out of the rocker arm 16 against the bias the return spring 33 are moved hydraulically in order to take up the play between the rocker arm 16 and the valve bridge 14-. The hydraulic device through which oil is fed from the engine's crankcase to the To operate the play piston 31, and by means of which the used oil is subsequently returned to the crankcase, if the braking process has ended is an advantageous feature of the invention.

The hydraulic device includes a solenoid control valve device 38 (^ ig. 1 to 3) »which according to the Representation in the bearing or holding part 22 is attached. However, it can be placed in any convenient location suitable for the intended purpose, for example at one end of the rocker arm shaft 21, or on the outside of the machine, the valve device 38 can be operated by means of a switch which is indicated schematically at 39. The switch 39 can

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be arranged for manual operation in the dashboard, or it can be a foot pedal or other convenient Be assigned to actuating device. The valve device 38 includes a solenoid valve member 40, which is a. normal position "" Ie shown in Fig. 2, in the the flow of oil from the crankcase to the backlash piston 31 is blocked or locked '. - ■.

When the controller 38 is energized, it will Solenoid valve member is pressed down against the force of a return spring into a position shown in FIG. 3, in which hydraulic working fluid can flow to the floating piston. This enables a pump 42 oil is sucked out of the crankcase 43 of the engine and with a predetermined high pressure via a supply line into the valve chamber and through side openings 45 to one Passage 46 is depressed. The passage 46 leads through the wall of the rocker arm shaft 21 in a line 48, which axially through the axis 21.

The line 48 is formed in that a spring separating strip 49 axially in the usual center hole on the rocker arm axis 21 is inserted in such a way that the hole is divided into two lines 48 and 51 extending in the longitudinal direction is. The line 48 is used for this. To lead oil to actuate the play piston 31, whereas the line

51 is used to carry oil for lubrication purposes

The conduit 51 is by means of a single feed passage

52 connected to the crankcase 43. Oil is withdrawn from crankcase 43 through passage 52 in a conventional manner pumped into the line 5Ί · The flowing in the line 51 Oil passes through various drain holes in the rocker arm shaft 21, one of which is shown at 53 (FIG. 6) is to lubricate the rocker arm 16 and the bumper 24. Lines 48 and 51 are at opposite ends sealed against each other.

In the line 48 entering pressure oil flows from a

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Opening 54- (Fig. 6 to 8) in the wall of the rocker arm axis 21 to a passage 55 in the rocker arm 16 and. Is at 56 with one end of a V / echs elvent ilkammer in the rocker arm T6 in connection. An opposite open end of the valve chamber 57 is from a trigger plate 58, which has a groove which has a relief opening 59 forms, which emerges at the uppermost area of the rocker arm 16, as best shown in Fig. ' 6 shown is. An opening 61 between the ends of the valve chamber 57 leads to a surface or an area on the rear or upper end of the bore 32 of the play piston

A combined shuttle valve and check valve device 62, which can be actuated in the valve chamber 57, controls the flow of pressure oil to the piston 31 after down and in the direction of the rocker arm 16 to press against the valve bridge 14 to the existing game in to include the rocker arm 16. It also controls subsequent release of the oil to the vent 59 'so that the play piston 31 by its spring 33 in the normal Position can be returned, which is shown in FIG. 6 and in which it sits at the rear end of its bore 32.

A shuttle valve member 63 of the combined valve device 62 has a cylindrical body which is provided with an axial bore in which a Seat 64 for a ball check valve 65 is arranged. A return spring 66 usually holds the check valve 65 on its seat, so that the connection from an inlet passage 67 through the check valve 65 therethrough with side ports 68 opening through the central portion of the body of the shuttle valve 63, blocked or blocked. is locked. The shuttle valve 63 has a normal position that it is under the bias of a return spring 69 (Fig. 7) occupies and in which its side openings through the wall of the valve chamber opposite a connection with the opening 61 blocked or blocked, the

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leads to the area or the area on the rear side of the play piston 31. The shuttle valve 63 has an opposite or moved position (FIG. 8), in which its side openings 68 are in alignment with the opening, and in which the opening 61 is not aligned with the relief opening 59 due to a rear part of the body of the shuttle valve of plate 58. connected is. A socket 71 » ä. ± e is fitted into the shuttle valve chamber, serves as a stop to limit the moved position of the shuttle valve 63 ·

Pressure oil, which in the passage 55 from the rocker arm axis 21 to the end 56 of the shuttle valve chamber flows, the valve moves against the bias of its return spring 69 to its side openings 68 with the Bring opening 61 into alignment as shown in Figure 8. During this process, the pressure oil flows through the seat of the ball check valve 65 to the rear of the play piston 31 and presses it downwards against the valve bridge 14. The oil pressure acting on the play piston 31 is sufficient to move the piston 31 against the force of its return spring 33 to a sufficient extent to take up the existing play, but it is not sufficient to cause the valve bridge 14 to die Exhaust valve 12 opens.

As long as the solenoid valve assembly 38 is energized, in order to maintain oil pressure on the clearance piston 31, the piston 31 maintains its displaced position and it is hydraulically locked by means of the one-way check valve 65 so that it does not return to its normal position · Every time the rocker arm 16 then through the auxiliary cam elevation 29 and through the main cam elevation 28 is pivoted, it acts on the extended play piston 31 and presses against the valve bridge 14, so that the exhaust valves 12 are opened. Within the machine

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In circuits, the exhaust valves 12 are opened at the usual time in the circuit by the squatting action of the main cam ridge 28 with the pushrod 24, and they are also opened near the end of the compression stroke by the cam action of the auxiliary cam ridge 29 above the pushrod 24.

When it is desired to return from the braking state of the machine to the normal driving state, the Solenoid control valve assembly 38 de-energized by the operator or driver. The solenoid spring 41 leads then the solenoid valve 38 to its normal position (Fig. 2) back, in which the inlet openings 44 of the valve 38 closed off with respect to the valve openings 45 and the latter are in communication with a vent 70 around the lower end of the solenoid valve 38. When the solenoid valve assembly 38 is de-energized, the pressure of the passages 46, 48 and 55 is between the outlets 45 of the solenoid valve 38 and the area or surface 56 at the rear of the shuttle valve chamber filling oil is relieved or canceled, since the oil via the solenoid valve openings 45 to the drain opening 70 flows. Oil emerging from the opening 70 drips into the Cylinder head 18 and usually finds its way back to crankcase 43.

Furthermore, if the pressure downstream of the shuttle valve 63 is released after the valve 38 has been de-energized, the spring 69 returns the shuttle valve 36 to its normal position, which is shown in FIG. this serves to connect the feed opening 61 of the play piston 31 to the trigger 59. At the back of the Oil located in the play piston 31 is then forced to flow out of the trigger 59 when the spring 33 touches the play piston 31 returns to its normal retracted position (Fig. 6). Oil flowing out of the fume cupboard 59 drips

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down onto the cylinder head 18 and finds its way back to the crankcase 43 in the usual way.

A desirable benefit of the hydraulic device is its ability to remove air and air bubbles too free «. , in particular in the passage 61 between the shuttle valve 63 and the bore 32 of the play piston 31 It should be noted in this connection that when the oil pressure in the passages 46, 48 and 55 is between the Solenoid valve 38 and the chamber 57 of the shuttle valve 63 is canceled, the check valve 65 by means of ^ his Spring 66 is closed and the pressure of the oil on the rear side of the play piston 31 through the drain opening 59 is relieved through · The opening 59 is at the top Area of the rocker arm 16 at a level above the level of the bore 32 of the play piston 31 and above the level of the horizontally arranged shuttle valve chamber 57, as can be seen best from FIG. Accordingly is the area of the hydraulic circuit between the shuttle valve 63 and the bore 32 of the play piston 31 filled with oil at all times. If any air bubbles should find a way to the circuit area beyond the check valve 65, they will rise through the oil at the top and escape through vent 59. Air bubbles are in the circuit area beyond the check valve 65 undesirable if the play piston 31 is pushed out hydraulically is because they are compressible and can cause the piston 31 to be withdrawn into its bore 32 accordingly when the rocker arm 16 rises from the auxiliary cam 29 is actuated. This retraction or such a '"sponge effect" of the play piston 31 could do so lead that the rocker arm 16 does not open the exhaust valves 12 properly.

Another advantage of the hydraulic device is that no undesirable pumping action of the Play piston 31 takes place relative to its bore 32,

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after the braking process has ended. This arises because the plunger is held seated 31 'by the return spring 33 in the retracted position, and at the bottom of its bore 32 and accordingly, every sound, or is held against solid when depressed by the rocker arm during operation of the machine against the valve bridge will. There is also no pumping action of the play piston 31 during the braking process, since the piston 31 is hydraulically locked in its extended position. Furthermore, air is constantly expelled from line 48 during the time while solenoid 38 is de-energized. During this period, the line 4-8 is constantly filled and flushed with oil, which enters the line 48 from the line 51 through drainage holes (not shown) in the partition strip 49. Oil pumped from the crankcase 43 is allowed to circulate constantly through the line 51 for lubrication purposes. This constant entry of oil from the line 51 into the line 48 to the hydraulic circuit between the solenoid valve 38 and the valve 63 causes a continuous flow of oil from the vent of the solenoid valve device 38, so that there is an effort to prevent any Air may build up in the hydraulic circuit. It should also be noted (FIG. 2) that the side openings of the solenoid valve device 38 slope upwardly from the passage 46 which opens through the wall of the rocker arm shaft 21 into the conduit 48. Accordingly, the openings 45 are at a level above the opening 46, so that the line 48 is never completely emptied and oil in this line always remains at a level above its inlet opening 46. This design also prevents the possibility of air entering the hydraulic circuit.

It should be noted that instead of using the flexible strip 49 in conjunction with the usual Center hole in the rocker arm shaft 21 to create the

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Passages 48 and 51 the rocker shaft for this purpose may be designed to have two separate longitudinally extending holes passing through Connection or drainage holes are connected to one another.

In the embodiment described above, these are Shuttle valve 63 and the check valve 65 shown in FIGS. 7 and 8 a ^ -s combined one-piece unit. In the embodiment according to FIGS. 9 and 10 the shuttle valve 63a and the check valve 65a, 64a are shown as two separate elements. At this second embodiment connects a passage 72 the Line 48 with a passage 73 · The check valve 65a, 64a is arranged in a branch 74 of the passage 73 and it usually blocks the passage 73 from a passage 75 which is connected to a passage 76 which leads to the rear of the bore 32a of the play piston 31a. The shuttle valve 63a is a solid part Plug part in a second branch 77 of the passage 73 is slidable. This second branch 77 usually connects the rear of the piston bore 32a of the Passages 76 and 78 with a trigger passage 79. At In operation of this embodiment, pressurized oil flows out of the Crankcase 43, when guided from conduit 48 to passage 72, to passage 73 and shifts at the same time the shuttle valve 63a to the passages 76 and 78 shut off the drain or drain and it opens the check valve 65a so that pressurized oil to the passage 76 flows and moves the play piston 31a. When the pressure of the oil in the passage 73 succeeds in interruption of the flow to line 48 is canceled, the check valve 65a is closed by its spring, and that Shuttle valve 63a is pushed back by its spring, so that the rear side of the play piston 31a is brought into connection with the trigger passage 79. The trigger passage 79 exits at a height above the passage 76,

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as shown at 80, for example.

It is to be understood that a separate rocker arm means, as in the embodiments described above is present, can be assigned to the exhaust valves of each cylinder of the engine, and that all rocker arms for the exhaust valves, which are pivoted on the Kippheb el axis 21, by only one solenoid control valve device 38 can be controlled, since the line 48 in the rocker arm shaft 21 the various Rocker arms, which are pivotably arranged on the axis, is common and since the line 51 is the different Rocker arms for lubrication purposes are also common.

According to the illustration, the rocker arm acts via a bridge 14 to actuate two exhaust valves 12. It is however, it should be understood that if a cylinder 10b (Pig. 11) has a single exhaust valve 12b, the bridge 14 is omitted is and the play piston 31b directly above the plunger 15b of the single exhaust valve 12b.

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Claims (14)

(^ UyMachine braking device for a machine with Rocker arm valve control, with at least one piston-cylinder, which has an exhaust valve, a rocker arm, which can be pivoted about a rocker arm axis against the valve is to push the valve into the open position, a holding or bearing device, which the rocker arm shaft supported on the machine, a rotary cam device that periodically cooperates with the rocker arm to this to pivot relative to the valve, however, due to play between the rocker arm and the valve is ineffective to pivot the rocker arm enough to push the valve into the open position, with a selectively actuatable device for taking up the game in order to eliminate said ineffectiveness of the ileal device, wherein the selectively operable device in a bore of the rocker arm a play piston, the one retracted position in which the game is present and an advanced position in which the game is received is, a hydraulic circuit for supplying hydraulic working fluid to the bore to reduce the clearance— piston to advance, and a selectively actuatable control valve means in the circuit to the To control the flow of the working medium in the circuit, characterized in that the rocker arm axis (21) with two separate lines (48, 51) extending in the longitudinal direction are formed, one of which (48) represents a part of the hydraulic circuit and the control valve device (38) with a passage device (54-, 55, 56, 61, Fig. 2, 6, 7) in the rocker arm (16) 309884/0607 connects, which leads to the bore (32) of the play piston (31), and of which the second line (51) is lateral Has lubrication openings (53) through the wall of the rocker arm shaft (21) and (at 52) is connected to oil out the crankcase (4-3) of the engine, and that the lines (48, 51) in one the lines from each other separating wall (49) or the like. Are connected to one another by holes. 2. Apparatus according to claim 1, characterized in that the control valve device (38) in the bearing or Holding device (22) is attached. 3. Apparatus according to claim 1 or 2, characterized in that a one-way check valve device (65) in the rocker arm (16) in the through device (56, 61) between the bore (32) of the play piston (31) and the Control valve device (38) is arranged, which a working medium flow in the passage device to the Allows drilling. 4. Apparatus according to claim 3, characterized in that a relief passage (Pig · 7) the passage means (61) connects between the check valve (65) and the bore (32) with a vent (59). 5. Apparatus according to claim 4, characterized by a shuttle valve (63), which is usually the flow of working medium via the check valve (65) to the bore (32) of the play piston (31) and the bore (32) of the play piston with the extraction opening (59) "connects. 6. Apparatus according to claim 5 »characterized in that that the vent (59j Pig · 6) is at a level above the level of the bore (32) of the play piston (31) and the passage device (61). 7. Apparatus according to claim 5 or 6, characterized in that the shuttle valve (63, Fig. 8) is a moving one Position in the passage device (57) in which 30988A / 06U7 233 ^ 711 the bore (32) of the play piston (31) with the flow through the check valve (6 $) is in connection and the connection of the bore (32, 61) with the exhaust valve (59) is blocked is β 8, device according to one of claims 1 to 7 *, characterized in that the control valve device (38j Fig. 2) is connected upstream of the non-return valve (65) kit of a supply line (44) which via a pump (4-2) to the crankcase ( 4-3) the machine guides 9 · Device according to claim 8, characterized _s that said control valve means (38) has a normal position (Fig. 2), in which the flow of the first conduit (48) is shut off from the supply line (44) shown below and dis line (48 ) is connected to a relief opening (? O). 10. The apparatus of claim 91 characterized in that the _$ relief opening (70, Fig. 2) is connected to the first line (48) via a passage ⁽¹ Jo), the is at a level approximately on deis lateral diameter of the line (48). 11. Device according to claim TO, characterized in that the oil flow in the second line (51) is continuous, a separating strip (49) separates the first line (48) from the second line (51), and through-holes or drainage holes the separating strip are provided, through which oil ^{can flow 1} from the second line into the first line, so that the first line in the usually closed position (Fig. 2) of the control valve (38) is continuously filled with oil from the second line (51 ) is flowed through, this oil flowing through the first line to the relief opening (70). 12 * Device according to one of claims 9 to 11, characterized in that the control valve device (38) has an actuated position (Fig. 3) in which oil from the supply line (44) to the first line (46, 48) can flow and connection of the latter with the relief 309884/0607 opening (70) is blocked. 13. Device according to one of Claims 1 to 12, characterized in that the control valve device (38) can be actuated by means of a solenoid and is under the control of an optionally actuatable switch (39 »Fig. 2). 14. Device according to one of claims 1 to 13, characterized by a device (62, Fig. 7 »8), which has a one-way check valve (65) in combination with a shuttle valve member (63) and in the rocker arm (16) in the passage device (56, 57 »61) between the control valve device (38) and the bore (32) of the Play piston (31) is arranged, and that the device is in a normal position (Fig. 7) when the oil pressure is released in the passage device (56) upstream of the device in which the bore (32) of the play piston (31) is in connection with a discharge opening (59), and through the shuttle valve member (63) from one Connection with the check valve member (65) is blocked. 15. Device according to claim 14, characterized in that the device (62) has a moved position (Fig. 8) under the pressure of hydraulic working medium, which is allowed to the passage device (56), in which position the shuttle valve member (63) closes the connection between the bore (32) of the play piston (31) and the discharge opening (59) and the connection of the bore (32) with the check valve member (65) which is movable under the hydraulic pressure in such a way that working medium can flow to the bore (61, 32). 309884/0607