DE2101750A1 - Improved control and actuation system for hydraulically driven winches, hoists, reels and the like - Google Patents

Description

Patent attorney

Karl Λ. B r o s e

D-3C23 f - ■ = ■■ > - Puüach

DBr / Fo Munich-Pullach, January 13, 1971

BOWMAKER (PIANO?) LIMITED, Watling Street, Cannock, Staffordshire, England

Improved control and actuation system A.

for hydraulically driven winches, hoists, reels and the like

The invention relates to an improved system for operating and controlling winches, hoists, reels or the like driven by a hydraulic motor.

In particular, the invention relates to systems that have a »

Comprise the hydraulic motor of the type is that tionary from a static "cylinder with a number of radial bores in which ^ s can be displaced a piston and having a cam ring that is rotationally driven by the piston. The cam surfaces of the cam ring in engagement with drive devices, such as with rollers arranged on the radially outer ends of the pistons or with the outer end faces of the pistons, and hydraulic fluid is optionally fed into the bores in order to displace the pistons radially in a predetermined sequence, thereby engaging under pressure of the drive devices with the cam surfaces rotates the cam ring, from which the drive to each

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can be removed in an expedient manner. Such motors are referred to below as motors of the type described.

Hydraulic motors of the type described are generally known and are used to drive winches, hoists and reels and the like use. Although in such applications the hydraulic motors of the type described however, it is extremely satisfactory very desirable to operate the winches or the like in a conventional manner, with the drive disengaged can be so as to enable the winch drum or the like to be freely rotatable or the drive overflows. For example, it is desirable to create a working condition in which the winch carried Load can fall freely under the action of gravity or in such a way, that the cable or the pull line can run out freely.

In systems with a mechanical drive transmission, this drive-free condition can easily be achieved by a disengageable one Achieved clutch assembly. With a hydraulic motor of the type described, however, the direct drive of the winch or the like is used. It was now recognized that in hydraulic systems where the source of Hydraulic fluid for the engine consists only of one or more pumps and not of a pressure accumulator, one Rotary movement of the cam ring in freewheel mode cannot be achieved without the risk of damaging the hydraulic motor can. The reason for this is that in a hydraulic motor of the type described, the flow of hydraulic fluid is arranged such that the pistons are forced radially outward, whereby the drive devices kept in engagement with the cam surfaces

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the. Even if the supply of hydraulic fluid is too the bores is interrupted or reduced, at least some of the pistons fall radially out of their bores under gravity to the outside, so that at least some of the drive devices with the cam surfaces are engaged. Consequently results when the cam ring is not driven by the drive devices but rotated by the torque applied by the load on the winch cable or the like becomes, the uncontrolled engagement of the drive devices with the cam surfaces of the rotating cam ring too much damage to the engine. Under certain circumstances, the cam surfaces can be damaged or the engine mount may crack or break.

An object of the invention is to provide a system for operating and controlling a winch, hoist or the like which is driven by a hydraulic motor of the type described to improve, whereby such a free fall of the load or free run-out of the load cable can be achieved without the aforementioned Risk of damage to the hydraulic motor occurs.

Another object of the invention is an improved hydraulic system for actuating and controlling a winch, a lifting device and the like which is driven by a hydraulic motor of the type described and thus to provide a winch, hoist or the like, which by such an improved hydraulic system is operated and controlled.

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Further advantageous details can be found in the description of a preferred embodiment of the invention in FIG following.

One of the broadest objects of the invention is a system for actuating and controlling conveyors, such as winches, hoists, reels or the like, which are driven by a hydraulic motor of the type described are driven, to which the supply of hydraulic fluid is carried out by pumping devices, with an improved valve device for controlling the flow of hydraulic fluid, the valve device is designed such that it generates a hydraulic pressure differential when actuated in the hydraulic motor, which on the piston acts to displace this radially inward so far that the drive devices from contact with the cam surfaces of the cam ring are kept away, which can then rotate freely.

In theory there may be many ways to achieve such a hydraulic pressure differential by controlling the Generate flow of hydraulic fluid through valve devices. However, practical considerations are more salient Significance because of the problems that can arise, e.g. the adaptability of the hydraulic motor, the overheating of the hydraulic fluid, the maximum pumping capacity of the pumping device and the The overall complexity and cost of manufacturing a particular valve assembly. Through the invention has provided a very useful system which avoids the aforementioned types of problems.

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One of the preferred ways of creating the hydraulic pressure differential in the hydraulic motor is in designing the valve devices such that the hydraulic pressure in the cylinder bores is reduced is, at the same time a low hydraulic pressure is maintained in the motor housing, so a to generate sufficient pressure differential for the radial displacement of the piston. That way, _> a relatively low hydraulic pressure in the motor housing se used to move the pistons and when the drive is to be restored it can be hydraulic Fluid is pumped into the cylinders to re-engage the drive mechanisms with the cam ring to bring, after which the hydraulic fluid to drive the engine again in the necessary Delivery rate can be supplied.

Likewise, within the basic concept of the invention, it is possible to design the Yenti devices only in such a way that that they control the flow of hydraulic fluid into the motor housing in such a way that the ra- J Pressure acting on the outer parts of the piston is generated which is greater than the hydraulic pressure in the cylinder bores, how it is applied to the radially inner parts of the pistons. This arrangement has the Disadvantage that the motor housing including the cam ring must be designed such that it the very resists high explosive loads due to the high hydraulic pressures used. In addition, that the pumping capacity of the pumping devices and the overheating of the hydraulic fluid lead to further problems ,can. Usually a hydraulic motor is the

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written type designed such that it works with no or very low hydraulic pressure in the motor housing and thus, in cases where only the invention is applied to existing hydraulic motors of the described Type should be applied, the aforementioned preferred type of generation of the hydraulic pressure differential very easy to use.

The valve devices must of course be designed in such a way that, when actuated, they conform with the necessary controls of the winch or the like become effective, which then either not must be operable or remain operable, e.g. if the load is released, the winch brake must be switched off stay. These fundamental considerations, however, will be will be more clearly understood from the description of an embodiment of the invention which follows hereinafter.

The invention is also intended to include winches, hoists, reels or the like, which by a hydraulic system according to the invention can be operated and controlled, just like the hydraulic system self.

One application of the invention consists in a hydraulic system for actuating and controlling a pipe-laying device, which can be attached to or contained in a tractor, the tractor preferably is a tracked vehicle.

In the following an embodiment of the invention with reference to the drawings, in which these are by way of example is illustrated, explained in more detail. It shows:

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Fig. Λ the front view of a pipe laying device according to the invention applied to a towing vehicle;

Figure 2 is a sketchy view of a

Hydraulic motor of the type described;

Fig. 3 is a circuit diagram of the hydraulic ύ actuation and control system for the boom of the Rohrlegvorrichtung of Figure 1; and

Figure 4- is a circuit diagram of the hydraulic actuation and control system for the counterweights and a hoist of the pipe-laying device.

The essential components of Rohrlegvorrichtung, which are mounted on the tractor, consisting of a saddle 1, on the one hand, from the advertising supported 2 and two winches 3 is a set hydraulically controlled counterweights M to that of the type described each by a hydraulic motor are driven and further details of which will be described later. On the other side of the saddle the boom H- is arranged, which is raised and lowered by one of the winches 3, and which at its outer end carries the pulley block 5, which is pulled up and lowered by the other winch 3. The pulley 5 and the boom 4 can be operated independently or simultaneously.

The hydraulic motors that drive the winches 3 are

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both of the type illustrated in Figure 2 a stationary cylinder block 6 with a number of radial bores, in each of which a piston 7 is displaceable is arranged, and a cam ring 8 which is rotatably formed driven by the piston on. The cam surfaces of the cam ring 8 are engaged with drive devices, for example those with the radially outer ones Ends of the piston connected rollers 9 or the outer end surfaces of the pistons, and hydraulic fluid is optional fed into the bores to move the piston 7 radially in a predetermined sequence, thereby engaging under pressure from the drive devices with the cam surfaces rotates the cam ring, of which in any usual way the drive is removed.

The hydraulic system illustrated in Figures 3 and 4 is used to actuate and control those previously described Device and its accessories. The driving force is independent of the engine of the tractor its drive transmission derived and used to drive the hydraulic pumps of fixed displacement, which hydraulic fluid feed into the three parts of the hydraulic system for actuation:

1) the boom 4;

2) the counterweights 2; and

3) the pulley block 5.

Each of these three parts of the system is described below with reference to Figures 3 and 4, wherein the figures are given in the form of hydraulic circuit diagrams and all control valves in the

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Zero location are illustrated.

1. THE ATJSLEGESSYSTEM

A fixed displacement hydraulic pump driven by the drive motor turns a suction filter 12 out of a open or low pressure reservoir 11 hydraulic fluid sucked in. The hydraulic fluid supply off the discharge line 13 of the pump 10 is controlled by a three-way valve 14, which is illustrated in the zero position. By means of the valve 14, the hydraulic fluid to a reversible hydraulic motor 15 of the described Type, which is directly connected to the winch drum and it can the hydraulic fluid in the Reservoir 11 are returned.

To raise the boom 4-, the valve 14 is in a shifted second position, which could be represented in the drawings by moving all the way to the right. In this second position, the motor 15 is rotated in one direction by the hydraulic fluid flowing through the line

16 fed to the motor and from this through the line

17 is expelled through the valve 14 into the line 18 and flows back into the storage container 11. Likewise hydraulic fluid is withdrawn from the motor housing through the line 19 back into the reservoir 11.

Connected to line 16 is a valve 20 which is normally closed, but which when energized serves to connect the line 16 to the line 21, which leads to the storage container 11. The valve

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20 is actuated by the engagement of a spring-loaded stop 22 which is designed in this way is that it comes into engagement with the boom when it is over a middle tier or another is raised in relation to the tractor at a predetermined altitude. As can be seen, in the case of such Actuation of the valve 20, the supply of hydraulic fluid prevented by the line 16 to the motor 15, since the line 16 via the valve 20 with the Return line 21 for the storage container 11 is connected and thus prevents further lifting of the boom will.

To lower the boom, the engine is changed by changing the direction of flow of the hydraulic fluid supplied to the motor 15 rotated in the opposite direction. This is done by moving the valve 14 to the third position reached, which corresponds to the leftmost position in the drawing. The hydraulic fluid is in this third position fed to the motor 15 from the pump delivery line 13 through the line 17, and from this through the Line 16 out through the valve 14 in the line 18 to ssen, which is connected to the storage container 11.

To keep the boom in the required position, the engine I5 has a counterbalance valve assembly on, in the figures in the rectangle designated by 23 is illustrated. This counterbalance valve arrangement is designed in such a way that it opens when a predetermined pressure in line 1? is fed by the pump so that the motor can work with full back pressure can.

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The jib winch has a conventional spring-loaded one Band brake, which is designed such that they are acted upon in the "off '^ position by a hydraulic pressure Brake cylinder 25 is held, which is connected to the valve 14 via a line 26. The hydraulic one Pressure is maintained in the brake cylinder 25 while the motor 15 is in either direction is driven. If there is no hydraulic fluid to the Motor 15 is fed, namely when the valve / In the zero position, as illustrated, is located the brake line to the reservoir return line 18 is open and the cylinder 25 is under hydraulic pressure relieved so that the brake is applied. In addition, the brake is applied automatically, if in one of the previously mentioned supply lines a loss of hydraulic fluid with the resulting pressure drop should occur. With the valve 14 is a pressure relief valve 84 connected and connected to line 13 and empties into line 18.

the

The lateral position of the counterweights (not shown) with respect to the tractor is hydraulically controlled by a dem Valve 14 similar three-way valve 27 is controlled. Two hydraulic cylinders 28, 29 are provided to move the counterweights transversely to the tractor center line by means of hydraulic fluid to move which through the line 30 from the smaller part of a hydraulic double pump 31 more solid Displacement is fed which hydraulic fluid sucks in from the reservoir 11 through a suction filter 83.

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When the valve 27 as illustrated in the middle
If the zero position is located, the pumped hydraulic fluid is passed through the valve 27 into the line 36 connected to the pulley system described later
fed. When the valve 27 is shifted to either a second or third position, the hydraulic fluid is fed to one of the ends of the hydraulic cylinders 28, 29 through a
of the lines 32, 33 and the displaced hydraulic fluid flows from the other end of the hydraulic cylinders 28, 29 through the other of the lines 32, 33. In the line 33 is a counterbalancing valve arrangement

34 provided. With the valve 27 is a pressure relief valve

35 connected and connected to line 30 and emptied into line 36.

THE REEL SYSTEM

The supply of hydraulic fluid to the pulley system is provided by the greater part of the double hydraulic pump 31 branched off. The hydraulic fluid in the discharge line 37 is passed through the line 39 into a three-way valve 38 and through line 40 into a two-way valve 41 headed. The delivery line 37 has a bypass filter 42 on.

The valve 38 is used to control a hydraulic motor
of the type described with two speeds. That
Valve 38 is essentially the same as the other three-way valves 27 and 14, except for the fact that it has a throttle 44 to allow flow in
to throttle the container 11 through the line 45, if
the valve 38 is in its second or third position

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is borrowed. With the valve 38 is a pressure relief valve 85 connected and connected to a line 39 and empties into the line 45.

The valve 41 is used to actuate the valve 46 of the hydraulic motor 43 'which in a manner known per se controls the speed of the motor. The valve 41 is connected to a line 47 which leads to the

The reservoir 11 guides and enables hydraulic fluid to flow through to the brake cylinder 48, the spring-loaded band brake of the winch (not shown), which is held in the "Aus ^M" position by pressure in the brake cylinder 48 in both working positions.

As for the operation of the brake cylinder 48, when the valve is in the zero position as illustrated in the drawings, the brake cylinder is not subjected to hydraulic pressure and the brake is thus in the applied position. The hydraulic fluid in the line 39 flows through the valve 38 via the return line 45 11 to the reservoir of the braking A cylinder 48 is also the reservoir 11 through the shuttle valve 5 ^ "the line 54 through the shuttle valve 50 and the line 49, the Valve 41 to line 40 and consequently to storage container 11 through valve 38 open.

When the valve 38 is in either its second or third position, that is when the hydraulic motor 43 is driven is, the brake cylinder 48 is acted upon with hydraulic pressure to the winch brake in the "off ^ position keep. When the engine speed control valve 41 is in the illustrated position, hydraulic fluid flows through line 40, diagonally through valve 41

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into line 49. The current through line 49 becomes divided into two partial flows, one of which is used to actuate the valve 46 at twice the motor speed corresponding position through the line 60 and the other for actuating the brake cylinder 48 through the shuttle valve 50, the line 54-, the shuttle valve 51 and is passed into the brake line 52. Of the Return flow from the brake cylinder when the brake is applied follows the same path in the opposite direction. When that engine speed s-control valve 41 is in its other position, the hydraulic fluid flows through the line 40 directly through the valve 41 into the line 53 and actuates the shuttle valve 50 to the line 60 close. The hydraulic flow then runs to the brake line 52 through the line 54 and the shuttle valve 51 »which in the manner previously described the same type is operated.

As can be seen from the preceding, the winch brake is applied when the hydraulic pressure in the brake line 52 is decreased. Such a reduction in hydraulic pressure will occur when the valve 38 is in its zero position is moved or if a feed line fails or under other circumstances that are later connected with the system for operating the pulley winch when the load falls freely.

The speed of the hydraulic motor 43 is in itself by actuating the drum valve 46 in a known manner controlled to which hydraulic fluid is fed through line 60 when control valve 41 is illustrated in FIG Position and the valve 38 are in its second or third position, with hydraulic fluid flowing through the line

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device 40 is supplied.

The hydraulic fluid for driving the motor 43 is supplied either through the line 58 or
through line 59 depending on the location of the
Valve 38. The return flow of hydraulic fluid from the motor 43 takes place through one of the lines 59 and 58. Here, too, an arrangement of valves is provided in order to maintain a predetermined level of the pressure acting on the motor pistons. This arrangement has a single-lane pressure limiting circuit 78 and a counterbalancing valve 79. With this arrangement of valves, the hydraulic fluid flows back through the valve 38 and the throttle 44 into the line 45 leading to the reservoir.

The core of the invention is that the hydraulic motor
43 can be operated so that the free fall of
Pulley load can be carried out and controlled without the risk of damaging the motor 43. Under
With reference to the preceding description and explanation, this mode of operation and control is explained in more detail below.

The hydraulic system for free fall connected to the control valve 56 is designed in such a way that it is only effective in the central zero position of the control valve 38, ie when the hydraulic motor is not driven, for example when there is a load on the pulley system in
the air hangs. This is carried out by means of a drain valve which is mechanically coupled to the actuating member of the valve 38 by a suitable connection. If the valve is either in its two

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th or third layer is the one leading to valve 64 Line 66 to the container 11 through the drain line 65 open and thus in the line 67 to the system Heard for free fall, no pressure to be built up. Consequently, the free fall of the load can only be achieved when the pulley valve 38 and drain valve 64 are in the working positions illustrated in the drawings are located.

The free fall of the lifting load is controlled by the control valve 56, to which hydraulic fluid flows from the control valve 27 of the counterweight system through the line 56 with the bypass filter 61. The control valve 56 for the free fall is illustrated in the inoperative position in which the brake line 52 to the reservoir 11 is open and the hydraulic flow through the line 55 ^{un (} i the line 62 with the throttle 63 directly through the valve 56 and the reservoir return line 57. The hydraulic fluid from the line 36 flows directly through the valve 56, through the line 68 to a check valve 69 in the line 70, to a line 10 and thus to an open reservoir 72, to which the flow is controlled by a check valve 73 The line 71 also has a pressure relief valve 74 for releasing the pressure in the line 36, but this pressure relief valve only functions as a check valve in the line 71 under normal conditions as described here.

The open storage container 72, which is part of the storage container 11 can be, is also connected to the motor housing by the line 75, so that a mi

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minimal pressure in the motor housing by the retained Maintain the opening pressure of the check valve 73 will. This pressure is chosen in accordance with the necessary hydraulic pressure differential that must be generated before free rotation of the cam ring of the hydraulic motor is permitted.

When the control valve 56 is "operated for the free fall", hydraulic fluid flows from the line 36 diagonally through the valve 56 into the line 62 and through the throttle 63 into the line 55 * through the shuttle valve 51 into the brake line 52, so the brake cylinder 48. Hydraulic fluid also flows from line 55 to line 67j connected to a pair of drum valves 76, 77 , which are thus actuated 78, 79 is released into an open container through the actuation of the valves 76, 77. After actuation of the control valve 56 for the free fall, the pressure in the housing of the motor 4-3 is maintained by opening the overpressure valve 74- so that the flow of hydraulic fluid continues to line 71. The pressure maintained in the motor housing by valve 73 is greater than the Dr uck in the cylinder bores of the engine and the pistons are pushed radially inward by the hydraulic pressure prevailing in the engine housing, so that the drive devices described above are moved out of engagement with the cam ring.

Accordingly, since the drum valves 76, 77 are only actuated by a relatively low control pressure, and the brake cylinder 48 has a much higher actuation

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pressure, the brake is released a little after the engine pistons have moved.

During operation it has been found that, if the pressure in the bores of the motor cylinder can be reduced to a very low level, a pressure of 1.4 to 2.6 kg / cm is sufficient for a hydraulic motor of the type described, which has a max
developed.

which has a maximum torque of 75 x 3 kgm per 7 kg / cm

To remove the pistons from the cam ring faster or, alternatively, to use a lower pressure in the motor housing can be made possible by the available supply of hydraulic fluid to the motor housing 43 can be enlarged by changing the boom system previously described with reference to FIG. Instead of, that the line 18 (FIG. 3) leads back directly to the container 11, this can be connected to the line 71 and so to container 72 through a pressure relief valve 73 lead. The fluid from the pump 10 then increases that from the smaller part of the hydraulic Double pump 31 delivered supply and thus increases the Available hydraulic fluid quantity for the motor housing, which corresponds to the requirement when the piston is pushed back should be.

To terminate the free fall of the load, the free fall control valve 56 is set to that shown in the drawing illustrated position moved back. However, there is no hydraulic pressure in the supply and exhaust lines 59 »58 of the engine. A positive pressure greater than the pressure in the motor housing must be generated quickly be to the motor 43 again to operate the bottle

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to make the winch ready for use. This development of hydraulic working pressure in motor 43 to move the pistons radially outward to bring the drive mechanisms back into engagement with the cam ring is achieved when the free fall control valve 56 is returned to the position illustrated in the drawing. When the valve 56 is in this position, the hydraulic fluid now flows from the line 46 through the line 68 and can overcome the two check valves 80, 81 in the line 82 connected to the motor lines 58, 59. The effective opening pressures of these valves 80, 81 are set lower than the pressure of the check valve 69, whereby the minimum working pressure, which is determined by the arrangement of the valves 78 and 79, is quickly restored. The hydraulic fluid also flows to the reservoir 11 from the brake line 52 through the shuttle valve 51 through the line 55 »through the throttle 63 in the line 62 and through the valve 56 to the line 57. This arrangement forms the exhaust of the brake cylinder 48, which is thus relieved and the brake is applied. The spool valves 76 and 77 are also relieved again by the drop in pressure in the line 67, a one-way throttle valve 84 in the line 67 forming a throttle device which delays the relief of the spool valves 76, 77 for a short time in order to ensure that the brake is slightly tightened before the motor pistons are moved outwards and so bring the drive mechanism back into engagement. The Piaschenzugwinde is then ready for operation under control of the valve 38.

It can be clearly seen that the opening and limiting press in relation to a special application with a

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special motor and pump capacity can be calculated and it can thus be a modified form of a hydraulic Circuit different from the one just described to achieve the same results can be used without to deviate from the spirit of the invention. In the described embodiment of the invention, however, simple operation and control are achieved, and other advantages are evident. It should be highlighted be that the three-way valves 14, 27 and 58 are arranged so that if any of these valves is in the zero position, for example when the tractor is idling, the hydraulic fluid is directly in the Container 11 is returned without being passed through the associated hydraulic circuits. These Arrangement is particularly advantageous as this prevents overheating of the hydraulic fluid, and additional oil coolers can be dispensed with.

The actuation of the brake of the pulley winch is synchronized with the operational readiness of the hydraulic motor, which ensures failure safety. In addition, the coupling of the drain valve 64 to the control valve 58 of the motor of the pulley winch forms a further fail-safe device. All manually operated control valves are of the "Todmann ^M" type and spring back into the zero position.

Furthermore, if an error should occur in the supply of hydraulic fluid to the winch motor 45 of the block and tackle, it is still possible to activate the free fall, for example to release a suspended load. If this is possible, since the supply of hydraulic fluid ZUT operation of the subsystem for the free fall vcc ^ egengewicht3system is taken.

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With the system according to the invention, a luffing crane can be made entirely by means of a hydraulic system using Hydraulic motors of the type described are controlled and operated will. This adds to the overall complexity and weight of hydraulic / mechanical assemblies reduced.

Although the preferred embodiment of the invention is yim The foregoing with reference to the operation and control of the winches and counterweights of a drilling jig, which can be attached to a tractor has been described, it will be for those skilled in the art It is clear that the invention can also be used in the original equipment of the tractor can or also in other devices, such as simple hoists, jib cranes and winches for towing or dredging by changing the hydraulic systems accordingly .

All technical details recognizable in the description and shown in the drawings are for the Invention of importance.

the J

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Claims (16)

PAiEENiEANSPKUCHE psystem for actuating and controlling hydraulically issued Winches, hoists, reels and the like that are driven by a hydraulic motor that has a stationary cylinder with a number of radial bores, in which ^ e displaceable pistons are arranged, each of which has an associated drive device, a cam ring with Cam surfaces is in engagement with the drive devices, and devices for the optional supply of hydraulic fluid provided to the bores for radial displacement of the piston in a predetermined sequence are, and the engagement under pressure of the drive devices with the cam surfaces rotates the cam ring, and the system comprises pumping devices for supplying hydraulic fluid to the hydraulic motor, characterized in that improved freewheeling devices for applying a hydraulic pressure differential on the pistons (7) of the hydraulic motor are provided in order to move the pistons (7) radially inwards and so the associated drive devices (9) out of contact with the cam surfaces of the cam ring (8) so that the cam ring (8) can rotate freely. 2. System according to claim 1, characterized in that the freewheeling devices means for applying a have hydraulic pressure inside a housing of the motor, the pressure upon actuation of the free 109882/1095 running devices is higher than the pressure prevailing in the cylinder bores. 3. System according to claim 1 and 2, characterized in that the free-running devices have means in order to reduce the hydraulic pressure prevailing in the cylinder bores when the free-wheeling devices are actuated. J 4-, system according to claim 3 »characterized in that in the free-running devices, the hydraulic pressure inside the motor housing is constantly maintained. 5. System according to claim 1, characterized in that the free-running device valve devices (56) for actuation of the device. 6. System according to claim 5, characterized in that means (73) are provided in the free-running device to a standing. Pressure in the cylinder bores maintain when d @ r engine is idling, WO d hydraulic with a source. Pressure (31) is connected to the interior of the housing of the motor (3-3) and the \ valve device (56) is designed such that, when actuated, devices (38, 64, 76, 77) for releasing the standing pressure from the Cylinder bores of the motor (4-3) actuated. ■ 7. System according to claim 6, characterized in that the interior of the motor housing to the hydraulic pressure I site (31) is not open only when the Ventilvor- ^s direction (5β) is actuated. 109882 / 1S3S 8. System according to claim 6 or 7, characterized in that that the valve device (56) is designed such that when it returns to its normal position after actuation connects a source of hydraulic pressure (31) to the cylinder bores of the engine (43) in order to to build up the standing pressure again. 9. System according to claim 6 or 7 *, characterized in that it has a normally applied brake on the winch assembly and hydraulic devices (48) are provided for releasing the brake when hydraulic pressure is applied to the cylinder bores to drive the motor (43), wherein the valve devices (56) are designed such that, when actuated, they apply hydraulic pressure to the brake release devices, the freewheel devices having means (63, 51, 76, 77) to ensure that the pressure is released from the cylinder bores before the release of the Brake occurs. 10. System according to claim 9 »characterized in that the valve device (56) is designed such that it returns to its normal position after actuation a source of hydraulic pressure (31) to the cylinder bores of the engine (43) to rebuild the standing Pressure connects, means (56, 80, 81, 78, 79, 61, 63) are provided which ensure that the brake is tightened until the standing pressure is generated again. 11. System according to one or more of the preceding claims, characterized in that it is manually operated Having control devices for the motor (43), wherein 109882/1095 the freewheel devices include means (64) coupled to the engine controller to ensure that the freewheel devices are only operated when the engine control is in the off position. 12. System according to one or more of the preceding claims, characterized in that the one with the freewheel device associated hydraulic pressure is obtained from one source (31) or several individual sources, the pumping devices that supply the motor (4-3) separately are. 13. A crane, characterized in that it includes a hoist with a freewheel device System according to one or more of the preceding claims, with movable counterweight devices including hydraulic to balance the load on the hoist and second pumping devices Devices for moving the counterweight devices, the hydraulic pressure for the freewheel devices is supplied by the second pumping devices. 14. A crane according to claim 13, characterized in that that the devices for moving the counterweight devices a second control means for the crane operator have and are designed such that the hydraulic pressure for actuating the freewheel device is only available when the second control means is in the off position. 109882/1095 15. Conveyor, characterized in that it a hydraulic system with idling device according to one or more of the preceding claims 1 to 12. 16. luffing crane, characterized in that it has a hoist with free-running device according to one or more of claims 1 to 12 and hydraulically operated devices for luffing the boom. 17 · Pipe laying device, characterized in that it has a saddle 1 which is designed to be fastened transversely on a tractor, with hydraulic controlled counterweights (2) on one side of the saddle (1), and a boom (4) on the other Side of the saddle are arranged, and hydraulically driven winches (3) for pivoting the boom (4) are provided and a cable hoist (5) hangs down from the boom (4), which is also hydraulic having driven hoisting winch devices for reeling up the cable, the hoisting devices free-wheeling devices according to one or more of the preceding claims 1 to 12. 109882/1095