US3815478A - Pipelayer hydraulic drawworks with free-fall - Google Patents

Abstract

In cable winding gear driven by a hydraulic motor of the kind having radial pistons driving a surrounding cam ring, a control is provided for applying differential pressure to the motor pistons so that they are disengaged from the cam ring which can then rotate freely. This provision enables the cable to be run out freely, so that, for example, in a crane free fall of the load can be allowed while avoiding damage to the motor. Pipelaying equipment including the free-fall provision is described.

Description

Matte States Patent [191 Axelsson et a1.

[ PIPELAYER HYDRAULIC DRAWWORKS WITH FREE-FALL [75] Inventors: Evald Gustav Axelsson, Stafford;

David Collier, Brewood, both of England [73] Assignee: Caterpillar Tractor Co., Peoria, 111. 221 Filed: on. 29, 1970 [21] Appl. No.: 84,978

[30] Foreign Application Priority Data June 26, 1970 Great Britain 31078/70 [52] U.S. Cl. 91/497 [51] Int. Cl. F0lb 13/06 [58] Field of Search 91/472, 491; 417/214;

[56] References Cited UNITED STATES PATENTS 2,453,309 11/1948 Douglas 418/82 2,789,542 4/1957 Vander Kay 91/48 2,831,554 4/1958 Reynolds 254/186 3,036,435 5/1962 Samuely 60/19 3,184,018 5/1965 Christison 254/186 3,230,715 l/l966 Klein et a1. 60/53 111 3,815,478 1 June 11, 1974 3,244,405 5/1966 Hanning 254/186 3,283,668 1/1965 Louhio 91/44 3,323,779 6/1967 Burnett 254/186 3,396,666 8/1968 Moochha|a.. 418/82 3,416,452 12/1968 Misulis 91/473 3,527,144 9/1970 Firth 91/472 3,662,551 5/1972 Denker.... 91/501 3,685,290 8/1972 Krusche 60/52 US FOREIGN PATENTS OR APPLICATIONS 1,004,080 12/1962 Great Britain 417/214 Primary ExaminerWi1liam L. Freeh Attorney, Agent, or Firm-Phillips, Moore, Weissenberger, Lempio & Strabala [5 7] ABSTRACT In cable winding gear driven by a hydraulic motor of the kind having radial pistons driving a surrounding cam ring, a control is provided for applying differential pressure to the motor pistons so that they are disengaged from the cam ring which can then rotate freely. This provision enables the cable to be run out freely, so that, for example, in a crane free fall of the load can be allowed while avoiding damage to the m0- tor. Pipe-laying equipment including the free-fall provision is described.

I 13 Claims, 4 Drawing Figures PATENTEHJHM 1 197 3.815478 SHEET 3 [IF 3 43 48 A a 46+ r 75 aEg 4 PIPELAYER HYDRAULIC DRAWWORKS WITH FREE-FALL This invention is concerned with improvements in or relating to systems for operating and controlling winches, hoists, windlasses or the like which are driven by hydraulic motors.

In particular, this invention is concerned with systems embodying a hydraulic motor of the kind including a stationary cylinder having a number of radial bores in each of which a piston is displaceable, and a cam ring which is rotatably driven by the pistons. The cam faces of the cam ring are engaged by driving means. such as rollers mounted on the radially outward ends of the pistons, or the outer end faces of the pistons, and hydraulic fluid is selectively supplied to the bores to radially displace the pistons in a predetermined sequence whereby the pressure engagement of the driving means with the cam faces rotates the cam ring from which the drive is obtained in any suitable manner. Such hydraulic motors as above described are herein referred to as of the kind specified.

Hydraulic motors of the kind specified are already well known and they are used for driving winches, hoists, windlasses or the like. Although in such applications hydraulic motors of the kind specified are very satisfactory, it is most desirable to be able to operate the winch or the like in the conventional manner in which the drive can be disengaged so as to allow the winch drum or the like to rotate freely or over-run the drive. For example, it is desirable to provide an operating condition such that the load supported by the winch can fall freely under gravity, or such that the cable or drag line can run out freely.

in systems having a mechanical drive transmission this drive-free condition can easily be achieved by a releasible clutch arrangement. However, with a hydraulic motor of the kind specified direct drive to the winch or the like is utilised. We have found that in a hydraulic system where the source of hydraulic fluid for the motor is derived solely from one or more pumps, and not a pressure accumulator, free-rotation of the cam ring cannot be obtained without risk of damaging the hydraulic motor. The reason for this is that in a hydraulic motor of the kind specified the flow of hydraulic fluid is arranged so that the pistons are urged radially outward whereby the driving means are maintained in engagement with the cam faces. Even if the supply of hydraulic fluid to the bores is interrupted or reduced, then at least some of the pistons will fall radially outwardly of their bores due to gravity so that at least some of the driving means engage with the cam faces. Accordingly, when the cam ring is not being driven by the driving means, but is rotated by the torque applied by the load on the winch cable or the like, the uncontrolled engagement of the driving means with the cam faces of the rotating cam ring causes excessive damage to the motor; in certain instances the cam faces are damaged, or the motor bearing may crack or break up.

It is an object of this invention to provide in a system for operating and controlling a winch hoist or the like driven by a hydraulic motor of the kind specified, an improvement whereby such free fall of the load, or free-running out of the load cable can be achieved without the aforementioned risk of damage to the hydraulic motor.

Further objects of this invention are to provide an improved hydraulic system for operating and controlling a winch, hoist or the like driven by a hydraulic motor of the kind specified, and to provide a winch, hoist or the like operated and controlled by such improved hydraulic system.

Other objectives will be apparent from the description of preferred embodiment of this invention given later herein.

According to the broadest aspect of this invention, we provide in a system for operating and controlling winding gear, such as a winch, hoist, Windlass or the like, driven by a hydraulic motor of the kind specified and to which hydraulic fluid is supplied by pump means, the improvement of valve means for controlling the flow of hydraulic fluid and which valve means on actuation is arranged to produce in the hydraulic motor a hydraulic pressure differential acting on the pistons to displace them radially inwards to an extent such that the driving means are maintained out of contact with the cam faces of the cam ring which can then rotate freely.

In theory there are probably many ways in which such hydraulic pressure differential may be developed by controlling the flow of hydraulic fluid through valve means. However, practical considerations are of paramount importance because of problems that may arise such as, the adaptability of the hydraulic motor, the overheating of the hydraulic fluid, the maximum flow capacity of the pump means, and the overall complexity and cost of providing a special valve arrangement. We believe that we have devised a most practical system which avoids the kinds of problems aforementioned.

One of the preferred ways of obtaining the hydraulic pressure differential in the hydraulic motor is to arrange for the valve means to reduce hydraulic pressure in the cylinder bores and to maintain a low hydraulic pressure in the motor casing so as to develop a pressure differential sufficient to displace the pistons radially inwards. In this manner a relativey low hydraulic pressure in the motor casing can be utilised to displace the pistons,and when the drive is to be restored, hydraulic fluid can be supplied to the cylinder to re-engage the driving means with the cam ring, and then hydraulic fluid for driving the motor may be supplied at the required flow rate.

Although it is envisaged within the scope of this invention to arrange for the valve means merely to control the flow of hydraulic fluid into the motor casing so as to develop therein a hydraulic pressure acting on the radially outer parts of the pistons greater than the hydraulic pressure in the cylinder bores as applied to the radially inner parts of the pistons, this has the disadvantage that the motor casing, including the cam ring will have to be designed to withstand very high bursting loads due to the high hydraulic pressures involved. Additionally, the flow capacity of the pump means and overheating of the hydraulic fluid may lead to further problems. Usually a hydraulic motor of the kind specified is designed to operate with no or very low hydraulic pressure in the motor casing, and thus where it is desired merely to apply our invention to existing hydraulic motors of the kind specified the aforementioned preferred way of developing the hydraulic pressure differential can most conveniently be adopted.

Of course the valve means has to be arranged to act, on actuation. in concert with the other essential operational controls of the winch or the like which must be maintained either inoperative or functional, for instance when the load is released the winch brake must be held off. However, these considerata will be fully understood from an embodiment of the invention which is described later herein.

This invention is also deemed to include a winch,

hoist. windlass or the like operated and controlled by a hydraulic system, embodying our improvement as well as the hydraulic system per se.

One application of this invention is in a hydraulic systern for operating and controlling pipe-laying apparatus adapted for attachment to, or incorporation in a tractor, preferably of the tracked type.

By way of example an embodiment of this application of this invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is a front-elevation of pipe-laying apparatus according to the invention mounted on a tractor;

FIG. 2V is a diagrammatic view of a hydraulic motor of the kindvspecifled;

FIG. 3 is aidiagram of the hydraulic operation and control system for the boom of the pipe-laying apparatus of FIG. I and;

FIG'. 4' is a diagram of the hydraulic operation and control system for counterweights and a hoist of the pipe-laying-apparatus.

The principal components of the pipe-laying apparatus which are mounted on the tractor comprise a saddle l on one side of which are carried a set of hydraulically controlledcounterweights 2 and two winches 3 each adapted to be driven by a hydraulic motor of the kind specified and of which further details will be given later. On the other side of the saddle is mounted theboom 4 which is raised and lowered by one of the winches 3, and the other end of the boom carries thehoist 5 which is raised and lowered by the other winch 3. Thehoist 5 andboom 4 can be operated independently or simultaneously.

The hydraulic motors driving the winches 3 are each of the kind shown in FIG. 2 and including a stationary cylinder block6 having a number of radial bores in each of which a piston 7 is displaceable, and acam ring 8 which is rotatably driven by the pistons. The cam faces of thecam ring 8 are engaged by driving means, such as rollers 9 mounted on the radially outward ends of the pistons, or the outer end faces of the pistons, and hydraulic'fluid is selectively supplied to the bores to displace the pistons 7 radially in a predetermined sequence whereby the pressure engagement of the driving means with the cam faces rotates the cam ring from which the drive is obtained in any suitable manner.

The hydraulic system depicted in FIGS. 3 and 4 is for operating and controlling the foregoing apparatus and its ancillary parts. The power is derived from. the tractor engine independently of drive transmission, and it is arranged to drive the fixed displacement hydraulic pumps which supply hydraulic fluid to the three parts of the hydraulic system for actuating:

i. theboom 4;

ii. thecounter-weights 2; and

iii. the hoist 5.

Each of these three parts of the system will now be described with reference to FIGS. 3 and 4 which are in the form of circuit diagrams with all the control valves shown in the neutral position. i. The Boom System A fixed displacementhydraulic pump 10 driven from the engine draws hydraulic fluid through asuction filter 12 from an open or low pressure reservoir II. Hydraulic fluid supply from theoutput line 13 of the pump [0 is controlled by a three position open-centre valve 14 which is shown in the neutral position. By means ofthevalve 14 hydraulic fluid may be supplied to a reversiblehydraulic motor 15 of the kind specified which is connected directly tothe winch drum, and the hydraulic fluid may be returned to thereservoir 11.

For raising theboom 4, thevalve 14 is displaced to a second position, which corresponds to moving it to the extreme right in the accompanying drawing. In this second position themotor 15 is rotated in one sense by hydraulic fluid supplied throughline 16 to themotor 15 and discharged through theline 17 through thevalve 14, to line 18 returning to thereservoir 11. Hydraulic fluid is also drained from the motor casing throughline 19 back to thereservoir 11.

Associated withline 16 is avalve 20 which is normally closed, but which on actuation serves to connect theline 16 withline 21 leading to thereservoir 11. Thevalve 20 is actuated by the engagement of a spring loadedabutment 22 which is arranged to be engaged by the boom if his raised to an over-centre position, or other predetermined attitude of elevation in relation to the tractor. As will be appreciated, on such actuation of thevalve 20, the supply of hydraulic fluid throughline 16 to themotor 15 is prevented as theline 16 is connected throughvalve 20 to the reservoir return line 2l,.and further elevation of the boom is prevented. For lowering the boom, themotor 15 is rotated in the opposite sense by changing the direction of flow of the hydraulic fluid supplied to themotor 15. This is achieved by displacing the valve I4 to a third position. corresponding to the extreme left in the accompanying drawing. In this third position, hydraulic fluid is supplied to themotor 15 from thepump output line 13 throughline 17 and discharged throughline 16, throughvalves 14 toline 18 which is connected to thereservoir 11.

In order to maintain the boom at a particular attitude, themotor 15 is provided with a counterbalance valve arrangement as depicted in the rectangular out-- line referenced 23. This counterbalance valve arrangement is adapted only to open when a predetermined high pressure is exceeded so that the motor can operate with full back pressure.

The boom winch is provided with a conventional spring operated band brake that is arranged to be held in the off" position by ahydraulic brake cylinder 25 which is connected to thevalve 14 by aline 26. Hydraulic pressure is maintained in thebrake cylinder 25 whilst themotor 15 is driven in either sense. When no hydraulic fluid is supplied to themotor 15, namely whenvalve 14 is in the neutral position as depicted, thebrake line 26 is open to thereservoir return line 18 and thehydraulic cylinder 25 is released so that the brake is applied. Additionally, if there should be a loss of hydraulic fluid with consequent reduction in pressure in any of the supply lines aforementioned the brake is automatically applied.

By way of further explanation of the boom system of FIG. 3, thecontrol valve 14, when in the neutral position shown, blockslines 16 and 17 fromlines 13 and 18 and communicates flow frompump totank 11 via conduits l3 and 18. In this condition, thebrake 25 is in communication with the tank via theconduit 26 which is a branch ofconduit 13.Brake 25, which is normally applied by spring force, is allowed to be applied to restrict movement of the boom. Release of the brake is accomplished by pressurization of the brake cylinder to overcome the spring bias when desired.

In order to lower the boom, theselector control valve 14 is shifted to position 92 in which it allows pump flow to be communicated tomotor 15 via theconduit 17 and to the counter-balance valve 93 via the conduit 94.

The orifice choke 96 modulates pilot flow to the counter-balance valve 93 and prevents over sensitive operation thereof. When the pilot pressure reaches the range of 300-500 psi, the valve 93 will shift to an open position in which is allowed communication between the motor ports 102 and thetank 11 via conduits the 97,98,99,16 and 18. The counter-balance valve 93 maintains a minimum back pressure range of 300-500 psi in the motor which pressure assures the release of the brake prior to the lowering of the boom and prevents cavitation in themotor 15.

The two-way relief valve 100 protects the motor circuitry by directing flow back to the motor inlet via theconduits 101 and 17 at such times that the load is excessive and back pressure in the motor reaches the 3,000 psilevel. This provision also reduces cavitation in the motor by supplying make-up fluid to the inlet ports when the load becomes excessive.

Shifting of theselector control valve 14 to position 90 places the circuit in a boom raise mode. In this condition, flow frompump 10 is communicated throughconduits 13 and 16 tomotor 15.Conduit 26 also communicates the pressurized pump flow to thebrake 25 for the release thereof. The two-way relief valve 100 establishes maximum motor pressure at 3,000 psi and relieves the system by communicating relief flow to thetank 11 via theconduits 101 and 17. Relief valve 106 protects thepump 10 from excessive pressure by communicatingconduit 13 withconduit 18 and withtank 11.

Check valves 104 and 105 are provided to block flow in the direction'indicated and to maintain fluid in the respective associated conduits and also to block flow to themotor 15 until after the brake spring force is overcome by pressurized fluid and the brake is released. The Counterweight System The lateral position of the counterweights (not shown) relative to the tractor is hydraulically controlled by a threeposition valve 27 similar tovalve 14. Twohydraulic cylinders 28, 29 are arranged to move the counterweights transversely of the tractor centreline by means of hydraulic fluid supplied throughline 30 from the small section of a doublehydraulic pump 31 of the fixed displacement type drawing hydraulic fluid through asuction filter 83 from thereservoir 11.

When thevalve 27 is in the central neutral position as depicted, the supply of hydraulic fluid is straight through is straight through the open-centre ofvalve 27 intoline 36 connected to the hoist system which is described later. If thevalve 27 is displaced into either a second or third position, then hydraulic fluid is supplied to one end of thehydraulic cylinders 28, 29

through one oflines 32, 33 and displaced hydraulic fluid flows out of the other end of thehydraulic cylinders 28, 29 through the other one oflines 32, 33. Acounterbalance valve arrangement 34 is provided inline 33. Apressure relief valve 35 is associated withvalve 27 and is connected toline 36.

The Hoist System The supply of hydraulic fluid to the hoist system is derived from the large section of the doublehydraulic pump 31. Hydraulic fluid inoutput line 37 is directed throughline 39 to a three-position valve 38, throughline 40 to a two-position valve 41 with theoutput line 37 including abypass filter 42.

Thevalve 38 is for controlling a two speedhydraulic motor 43 of the kind specified.Valve 38 is substantially the same as the other threeposition valves 27 and 14, except that it includes a restrictor 44 which serves to throttle flow to thereservoir 11 throughline 45 when thevalve 38 is in its second or third position.

Thevalve 41 is provided for operating thevalve 46 of thehydraulic motor 43 that controls, in known manner, the speed of the motor. Thevalve 41 is connected to aline 47 leading to thereservoir 11, and in either operative position provides a through passage for hydrau- Iic fluid to thebrake cylinder 48 of the spring-operated band'type winch brake (not shown) that is held off by thebrake cylinder 48.

With reference to the operation of thebrake cylinder 48, when thevalve 38 is in the neutral position depicted in the drawing there is no hydraulic fluid supplied to the brake cylinder 48'and the brake is in the applied position. The hydraulic fluid inline 39 flows through the open centre ofvalve 38 to thereservoir 11 viareturn line 45. Thebrake cylinder line 52 is also open to thereservoir 11 throughshuttle valve 51,line 54 throughshuttle valve 50, and theline 49,valve 41 toline 40 and thence to thereservoir 11 throughopencentred valve 38.

When thevalve 38 is in either its second or third positions, that is when thehydraulic motor 43 is being driven, hydraulic fluid is supplied to thebrake cylinder 48 to hold the winch brake in the off" position. When the motorspeed control valve 41 is in the position depicted, hydraulic fluid flows throughline 40 through port p to port a ofvalve 41. Flow is then throughline 49, throughshuttle valve 50 intoline 54 to actuateshuttle valve 51 and into thebrake line 52. The actuation of theshuttle valve 51 prevents the return flow of hydraulic fluid to thereservoir 11 throughline 57. When the motorspeed control valve 41 is in its other position, the hydraulic fluid flows throughline 40, through port p to port b ofvalve 41, throughline 53 to actuateshuttle valve 50 to closeline 60. The flow is then to thebrake line 52 throughline 54 andshuttle valve 51 which is actuated in the same way as just described.

As will be appreciated, when there is a reduction in hydraulic pressure in thebrake line 52, the winch brake will be applied. Such reduction in hydraulic pressure will occur whenvalve 38 is moved to the neutral position, or if a supply line fails, or under other circumstances which will be explained later in connection with the system for operating the hoist winch with free fall of the load.

The speed of the hydraulic 43 is controlled in known manner by the actuation ofspool valve 46 to which hydraulic fluid is supplied through line when the conis either throughline 58,-or throughline 59 dependingon the position ofvalve 38. The return'flow of hydraulic fluid from themotor 43 is through eitherline 59 or 58. There is also provided an arrangement of valves to maintain a predetermined pressure acting on the motor pistons. This arrangement includes a non-returnpressure limiting circuit 78 and acounter-balance valve 79. From this arrangement of valves the hydraulic fluid returns through thevalve 38,restrictor 44 to theline 45 leading to thereservoir 11.

The crux of this invention is that thehydraulic motor 43 can be operated so that free fall of the hoist load can be obtained, andcontrolled without risk of damage to themotor 43. This operation and control will now be explained having regard to the foregoing description and explanation. a

The free-fall hydraulic system associated withcontrol valve 56 is arranged so that it can only be effective I when the hoistcontrol valve 38 is in the neutral central position, that is when the hydraulic motor is not being driven, such as when a load is suspended on the hoist in mid-air.- This is done by providing adrain valve 64 which is mechanically coupled by a suitable linkage to the operating linkage ofvalve 38. Whenvalve 38 is in either its second or third position, theline 66 leading tovalve 64 is open to the reservoir 11' throughdrain line 65 and. thus pressure cannot be developed inline 67 which is in the free fall system. Accordingly, free fall of the load can only be obtained when the hoistvalve 38 anddrain'valve 64 are in the operative positions depicted in the accompanying drawing; 1

The free fall of the hoist load is controlled by thecontrol valve 56 to which hydraulic fluid flows from thecontrol valve 27 of the counterweight system, throughline 36 including by -pass filter 61. The freefall control valve 56 is depicted in the inoperative position whereby thebrake line 52 is open to thereservoir 11, flow being throughline 55, line '62 including restrictor 63, through port B to port T of thevalve 56 to' thereservoir return line 57. The hydraulic fluid flows through port P to portAof valve 56, through line'68 to anon-return valve 69in'line 70, to aline 71 and thus to anopenreservoir 72 to which flow is controlled by anon-return valve 73 having a predetermined opening pressure. Theline 71 also includes apressure relief valve 74 for relieving the pressure inline 36, but under normal conditions as now being described, thisrelief valve 74 merely acts as a non-return valve inline 71.

,Theopen reservoir 72 which may be integral withreservoir 11, is also connected to themotor casing bycylinder 48. Hydraulic fluid also flows from the line 62 toline 67 connected to a pair ofspool valves 76, 77,

which are thus actuated. The lower hydraulic pressure which is present in the idlehydraulic motor 43 and which is determined by thevalves 78, 79 is vented to an open reservoir through thevalves 76, 77 on their actuation, and thus the pressure maintained in the motor casing by thevalve 73 is greater than that in the motor cylinder bores and the pistons are displaced radially inwards by the hydraulic pressure in the motor casing so that the driving means as aforedescribed is moved out of engagement with the cam ring.

Accordingly, as thespool valves 76, 77 are merely operated by a relatively low pilot pressure, and thebrake cylinder 48 hasa much higher actuation pressure,-the brake is released slightly after the motor pistons have been displaced.

in practice, we have found that if the motor cylinder bore pressure can be reduced to a very low figure. then a'motor casing pressure of from 22 p.s.i. to 36 psi. is sufficient in a hydraulic motor of the kind specified developing a maximum torque of 545 ft. lbs, per psi.

To stop the free fall of the load, the freefall control valve 56 is returned into the position as depicted in the drawing. However, now there is no hydraulic pressure in the motor supply anddischarge lines 59, 58. A positive pressure, greater than the motor casing pressure has to be developed quickly to render themotor 43 operative again for operating the hoist winch. This development of operative hydraulic pressure inthemotor 43 to displace the pistons radially outwards to re-engage the driving meanswith the cam ring is achieved when the freefall control valve 56 is returned to position depicted in the drawing. Whenvalve 56 is in' this position hydraulic fluid fromline 36 flowing now throughline 68 can overcome the twonon-return valves 80, 81 inline 82 connected to motor lines'58, 59. The operating opening pressures of thesevalves 80, 81- are set lower than thenon-return valve 69, thus the minimum operating pressure determined by the arrangement ofvalves 78 and 79 is quickly restored. Hydraulic fluid also flows to the reservoir ll from thebrake line 52, through shuttle 'valve 51 throughline 55,-through the restrictor 63 in'line 62, and throughvalve 56 toline 57. This exhausts thebrake cylinder 48 which'is releasedand the brake is applied. Thespool valves 76 and 77 are also released again by the pressure drop inline 67, buta throttlenon-return valve 84 inline 67 the restrictor 63 provides a restriction which delays the release of thespool valves 76, 77 for a short time to ensure that the brake is applied slightly before the motor pistons are displaced outwards to re-engage the driving means. The hoist winch is then ready for operation under the control ofvalve 38.

It will be appreciated that the opening and limiting pressures are calculated in relation to a specific application with a particular motor and pump capacity, and without detracting from the scope of this invention, a modified form of hydraulic circuit as just described could be employed to achieve the same result. However, in this embodiment of the invention simple operation and control is achieved. and other advantages are obtained.

it should be noted that the three-position valves I4. 27 and 38 are of the open-centre kind so that when any of these valves are maintained in the neutral position. such as when the tractor is idling, the hydraulictluid is returned directly to the reservoir 11] without passing through the associated hydraulic circuits. This arrangement is most advantageous because excessive heating of the hydraulic fluid is prevented and the provision of additional oil coolers can be avoided.

The actuation of the hoist-winch brake is synchronised with the readiness of the hydraulic motor, and this provides a fail-safe feature. Additionally, the coupling of the drain valve 164 to the hoist winch motor control valve 138 provides another fail-safe feature. Each of the manually operable control valves are of the dead-man type biased to return to the neutral position,

Additionally, if'there should be a failure in the hydraulic fluid supply to the hoist winch motor 143 it is still possible to operate the free fall to release, for instance a suspended load. This is because the hydraulic fluid supply to actuate the free fall sub-system is taken from the counterweight system With this invented system a luffing crane can be controlled and operated completely by a hydraulic system embodying hydraulic motors of the kind specified. This reduces the overall complexity and weight of hydraulic/mechanical arrangements.

Although the preferred embodiment of this invention as just described is directed to operating and controlling the winches and counterweights of pipe-laying apparatus adapted for attachment to a tractor, it will be appreciated by those familiar with hydraulic engineering that this invention may be embodied in the original equipment of the tractor or embodied in other apparatus such as simple lifting hoists, jib cranes, and winches for trawling or dredging by appropriately modifying the hydraulic systems.

Weclaim: A v 1. In a system for'operating and controlling a winding gear driven by a rotary hydraulic motor of the kind including a first member having a plurality of radial bores, a motor element displaceable in each of the bores and each having an associated driving means, a cam ring having cam faces engaged by the driving means and means for selectively supplying hydraulic fluid to the bores to displace the motor elements radially in a predetermined sequence and by pressure-engagement of the driving means with the cam faces to produce relative rotation between the cam ring and said first member, the system includingpump means for supplying hydraulic fluid to the hydraulic motor, normally applied brake means for said winding gear, fluid pressure means including fluid communication means for releasing said brake means, the improvement comprising; free-run means including fluid communication means for applying to the motor elements of the hydraulic motor a hydraulic pressure differential to displace the motor elements radially inwardly and withdraw the associated driving means from contact with the cam faces of the cam ring whereby the cam ring can rotate freely, said free-run means including means for preventing said fluid pressure means from releasing said brake means until said pressure differential has been developed to condition said motor elements and associated driving means to move radially inwardly away from contact with said cam faces of said cam ring, the hydraulic pressure for the free-run means being derived from a source separate from the pump means supplying the motor.

2. The invention of claim 1 including a casing for said hydraulic motor and means for applying, on actuation of the free-run means, a hydraulic pressure inthe interior of said casing of the motor higher than that obtain ing in said bores.

3. The invention of claim 1 including means for re ducing, on actuation of the free-run means, standing hydraulic pressure in said bores.

4. The invention ofclaim 2 further including valve means for actuating the free-run means.

5. The invention ofclaim 4 including a casing for said hydraulic motor and wherein said valve means are adapted, on actuation. to connect a source of hydraulic pressure to the interior of said casing.

l 6. The invention-ofclaim 5 further including means for maintaining a standing pressure in the bores when the motor is idle and wherein said valve means, on actuation, operate means for releasing said standingpressure from the bores of the motor.

7, In a system for operating and controlling a winding gear driven by a rotary hydraulic motor of the kind including a first member having a plurality of radial bores, a motor element displaceable in each of the bores and each having an associated driving means, a cam. ring having cam faces engaged by the driving means and means for selectively supplying hydraulic fluid to the bores todisplace the motor elements radially in a predetermined sequence and by pressure engagement of the driving means with the cam faces to produce relative rotation between the cam ring and said first member, .the system including pump means for-supplying hydraulic fluid to 'the hydraulic motor.

rotate freely; said free-run meansincluding means for preventingsaid fluid pressure means from releasing said brake'means until said pressuredifferential has been developed to condition said motor elements and associated driving means to move radially'inwardlyv away from contact with said cam faces of'said cam ring, valve means forac'tuating the free-run means, a casing for hydraulic motor and wherein said'valve means are adapted, on actuating, to connect a source of hydraulic pressure to the interior of said casing, means for maintaining a standing pressure in the bores when the motor is idle and wherein said valve means, on actuation, operate means for releasing said standing pressure from the bores of the motor, said valve means, on restoration to its normal position after actuation, acting to connect a source of hydraulic pressure to the bores of the motor to restore the standing pressure. I

8. The invention of claim 7 wherein said valve means. on restoration of its normal position after actuation. connect a source of hydraulic pressure to the bores of the motor to restore the standing pressure, said means for preventing brake means release being also provided for ensuring that the brake means is applied before the standing pressure is restored. I

9. in a system for operating and controlling a winding gear driven by a reversible rotary hydraulic motor, driving means for selectively supplying hydraulic fluid to said rotary hydraulic motor to rotate said hydraulic motor and said winding gear, said driving means including first supply means for supplying hydraulic pressure fluid to said hydraulic motor, normally applied brake means for said winding gear, fluid pressure means including fluid communication means for releasing said brake means, free-run means including fluid communication means for applying to a portion of the hydraulic motor a hydraulic pressure to allow said hydraulic motor to rotate freely without load, said free-run means including second supply means for supplying said hydraulic motor portion, said second supply means including a source of hydraulic fluid separate from the source of hydraulic fluid for said drive means, said freerun means including means for preventing said fluid pressure means from releasing said brake means until said hydraulic pressure has been supplied to said portion of said motor to condition said motor to rotate freely without load, said driving means for said reversible rotary hydraulic motor further including a motor control valve for controlling flow of hydraulic fluid to said hydraulic motor for driving rotation thereof, said control valve having a first portion for supplying fluid to cause said motor to rotate in a first direction, a second position'for supplying fluid to cause said motor to rotate in the reverse direction, and a neutral position in which fluid flow to and from said hydraulic motor is blocked and a hydraulic fluid lock is created which retards rotation of said hydraulic motor in either of said first or reverse directions, said free-run means further including a secondary valve means separate from said motor control valve for controlling the supply of hydraulic fluid pressure to said motor portion.

10. in a system for operating and controlling a winding gear driven by a rotary hydraulic motor, driving means for selectively supplying hydraulic fluid to said rotary hydraulic motor to rotate said hydraulic motor and said winding gear, said driving means including first supply means for supplying hydraulic. pressure fluid to said hydraulic motor, normally applied brake means'for said winding gear, fluid pressure means including fluid communication means for releasing said brake means, free-run means including fluid communication rneans for applying to a portion of the hydraulic motor a hydraulic pressure to allow said hydraulic motor to rotate freely without load, said free-run means including second supply means for supplying said hydraulic motor portion, said second supply means including a sourceof hydraulic fluid separate from the source of hydraulic fluidfor said drive means, said freerun means including means for preventing said fluid pressure means from releasing said brake means until said hydraulic pressure has been supplied to said portion of said motor to condition said motor to rotate freely without load, said free-run means further including tertiary valve means for preventing said rotary hydraulic motor from returning from the freely rotating condition to the driving condition prior to the reapplication of said brake means.

11. in a system for operating and controlling a winding gear driven by a rotary hydraulic motor of the kind including a first member having a plurality of radial bores, 21 motor element displaceable in each of the bores and each having an associated driving means, a cam ring having cum l'aces engaged by the driving means and means for selectively supplying hydraulic fluid to the bores to displace the motor elements radially in a predetermined sequence and by pressure engagement of the driving means with the cam faces to produce relative rotation between the cam ring and said first member, the system including pump means for supplying hydraulic fluid to the hydraulic motor, normally applied brake means for said winding gear, fluid pressure means including fluid communication means for releasing said brake means, the improvement comprising; free-run means including fluid communication means for applying to the motor elements of the hydraulic motor a hydraulic pressure differential to displace the motor elements radially inwardly and withdraw the associated driving means from contact with the cam faces of the cam ring whereby the cam ring can rotate freely, said free-run means including means for preventing said fluid pressure means from releasing said brake means until said pressure differential has been developed to condition said motor elements and associated driving means to move radially inwardly away from contact with said cam faces of said cam ring, an operators control for the motor wherein the freerun means includes means coupled to the operator's motor control for ensuring that the free-run means can only be actuated when the motor control is in the off position.

12. In a system for operating and controlling a winding gear driven by a rotary hydraulic motor, driving means for selectively supplying hydraulic fluid to said rotary hydraulic motor to rotate said hydraulic motor and said winding gear, said driving means including first supply means for supplying hydraulic pressure fluid to said hydraulic motor, normally applied brake means for said winding gear, fluid pressure means including fluidcommunication means for releasing said brake means, free-run means including fluid communication means for applying to a portion of the hydraulic motor a hydraulic pressure to allow said hydraulic motor. to rotate freely without load. said free-run means including second supply means for supplying said hydraulic motor portion, said second supply means including a source of hydraulic fluid separate from the source of hydraulic fluid for said drive means, said freerun means including means for preventing said fluid pressure means from releasing said brake means until said hydraulic pressure has been supplied to said portion of said motor to condition said motor to rotate freely without load.

13. The invention ofclaim 12 wherein said rotary hydraulic motor is reversible and said hydraulic motor drive means further includes a motor control valve for controlling flow of hydraulic fluid to said hydraulic motor for driving rotation thereof, said control valve having a first position for supplying fluid to cause said motor to rotate in a first direction, a second position for supplying fluid to cause said motor to rotate in the reverse direction, and a neutral position in which fluid flow to and from said hydraulic motor is blocked and a hydraulic fluid lock is created which retards rotation of said hydraulic motor in either of said first or reverse directions.

a k a: k a

V UNITED STATES PATErgr OFFICE A 6 CERTIFICATE OF CCRRECTECN Patent No. 3,815,?8 Dated June 11, 97

Inyentofls) EVALD G. AXELSSON et 8.1

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

lnF ig. 3 of the drawing, numerals 90, 91, 92, 93, 94, 96, 97, 98, 99', 100', 101, 102, 103, 10M, 1o5 and 106 are added along with lead lines where indicated;

In Fig. 4 of the drawing,'letters A; B, a, b,

P, p and T are added along with lead lines where indicated.

Column 10, line 3, change "1" to --2--Column 10,line 6, change "2" to ---l--.

Signed and sealed thi-a 5th day of November. 1974.,

(SEAL) Attest:

McCOY M, GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents UGCOMWDC 603764 69 -'ORM P0405) (IO-69) f" i an covmmuzm mum-c ovnc: 1 Inc o-su-uc

Claims (13)

1. In a system for operating and controlling a winding gear driven by a rotary hydraulic motor of the kind including a first member having a plurality of radial bores, a motor element displaceable in each of the bores and each having an associated driving means, a cam ring having cam faces engaged by the driving means and means for selectively supplying hydraulic fluid to the bores to displace the motor elements radially in a predetermined sequence and by pressure engagement of the driving means with the cam faces to produce relative rotation between the cam ring and said first member, the system including pump means for supplying hydraulic fluid to the hydraulic motor, normally applied brake means for said winding gear, fluid pressure means including fluid communication means for releasing said brake means, the improvement comprising; free-run means including fluid communication means for applying to the motor elements of the hydraulic motor a hydraulic pressure differential to displace the motor elements radially inwardly and withdraw the associated driving means from contact with the cam faces of the cam ring whereby the cam ring can rotate freely, said free-run means including means for preventing said fluid pressure means from releasing said brake means until said pressure differential has been developed to condition said motor elements and associated driving means to move radially inwardly away from contact with said cam faces of said cam ring, the hydraulic pressure for the free-run means being derived from a source separate from the pump means supplying the motor.

2. The invention of claim 1 including a casing for said hydraulic motor and means for applying, on actuation of the free-run means, a hydraulic pressure in the interior of said casing of the motor higher than that obtaining in said bores.

3. The invention of claim 1 including means for reducing, on actuation of the free-run means, standing hydraulic pressure in said bores.

4. The invention of claim 2 further including valve means for actuating the free-run means.

5. The invention of claim 4 including a casing for said hydraulic motor and wherein said valve means are adapted, on actuation, to connect a source of hydraulic pressure to the interior of said casing.

6. The invention of claim 5 further including means for maintaining a standing pressure in the bores when the motor is idle and wherein said valve means, on actuation, operate means for releasing said standing pressure from the bores of the motor.

7. In a system for operating and controlling a winding gear driven by a rotary hydraulic motor of the kind including a first member having a plurality of radial bores, a motor element displaceable in each of the bores and each having an associated driving means, a cam ring having cam faces engaged by the driving means and means for selectively supplying hydraulic fluid to the bores to displace the motor elements radially in a predetermined sequence and by pressure engagement of the driving means with the cam faces to produce relative rotation between the cam ring and said first member, the system including pump means for supplying hydraulic fluid to the hydraulic motor, normally applied brake means for said winding gear, fluid pressure means including fluid communication means for releasing said brake means, the improvement comprising; free-run means including fluid communication means for applying to the motor elements of the hydraulic motor a hydraulic pressure differential to displace the motor elements radially inwardly and withdraw the associated driving means from contact with the cam faces of the cam ring whereby the cam ring can rotate freely, said free-run means including means for preventing said fluid pressure means from releasing said brake means until said pressure differential has been developed to condition said motor elements and associated driving means to move radially inwardly away from contact with said cam faces of said cam ring, valve means for actuating the free-run means, a casing for hydraulic motor and wherein said valve means are adapted, on actuating, to connect a source of hydraulic pressure to the interior of said casing, means for maintaining a standing pressure in the bores when the motor is idle and wherein said valve means, on actuation, operate means for releasing said standing pressure from the bores of the motor, said valve means, on restoration to its normal position after actuation, acting to connect a source of hydraulic pressure to the bores of the motor to restore the standing pressure.

8. The invention of claim 7 wherein said valve means, on restoration of its normal position after actuation, connect a source of hydraulic pressure to the bores of the motor to restore the standing pressure, said means for preventing brake means release being also provided for ensuring that the brake means is applied before the standing pressure is restored.

9. In a system for operating and controlling a winding gear driven by a reversible rotary hydraulic motor, driving means for selectively supplying hydraulic fluid to said rotary hydraulic motor to rotate said hydraulic motor and said winding gear, said driving means including first supply means for supplying hydraulic pressure fluid to said hydraulic motor, normally applied brake means for said winding gear, fluid pressure means including fluid communication means for releasing said brake means, free-run means including fluid communication means foR applying to a portion of the hydraulic motor a hydraulic pressure to allow said hydraulic motor to rotate freely without load, said free-run means including second supply means for supplying said hydraulic motor portion, said second supply means including a source of hydraulic fluid separate from the source of hydraulic fluid for said drive means, said free-run means including means for preventing said fluid pressure means from releasing said brake means until said hydraulic pressure has been supplied to said portion of said motor to condition said motor to rotate freely without load, said driving means for said reversible rotary hydraulic motor further including a motor control valve for controlling flow of hydraulic fluid to said hydraulic motor for driving rotation thereof, said control valve having a first portion for supplying fluid to cause said motor to rotate in a first direction, a second position for supplying fluid to cause said motor to rotate in the reverse direction, and a neutral position in which fluid flow to and from said hydraulic motor is blocked and a hydraulic fluid lock is created which retards rotation of said hydraulic motor in either of said first or reverse directions, said free-run means further including a secondary valve means separate from said motor control valve for controlling the supply of hydraulic fluid pressure to said motor portion.

10. In a system for operating and controlling a winding gear driven by a rotary hydraulic motor, driving means for selectively supplying hydraulic fluid to said rotary hydraulic motor to rotate said hydraulic motor and said winding gear, said driving means including first supply means for supplying hydraulic pressure fluid to said hydraulic motor, normally applied brake means for said winding gear, fluid pressure means including fluid communication means for releasing said brake means, free-run means including fluid communication means for applying to a portion of the hydraulic motor a hydraulic pressure to allow said hydraulic motor to rotate freely without load, said free-run means including second supply means for supplying said hydraulic motor portion, said second supply means including a source of hydraulic fluid separate from the source of hydraulic fluid for said drive means, said free-run means including means for preventing said fluid pressure means from releasing said brake means until said hydraulic pressure has been supplied to said portion of said motor to condition said motor to rotate freely without load, said free-run means further including tertiary valve means for preventing said rotary hydraulic motor from returning from the freely rotating condition to the driving condition prior to the re-application of said brake means.

11. In a system for operating and controlling a winding gear driven by a rotary hydraulic motor of the kind including a first member having a plurality of radial bores, a motor element displaceable in each of the bores and each having an associated driving means, a cam ring having cam faces engaged by the driving means and means for selectively supplying hydraulic fluid to the bores to displace the motor elements radially in a predetermined sequence and by pressure engagement of the driving means with the cam faces to produce relative rotation between the cam ring and said first member, the system including pump means for supplying hydraulic fluid to the hydraulic motor, normally applied brake means for said winding gear, fluid pressure means including fluid communication means for releasing said brake means, the improvement comprising; free-run means including fluid communication means for applying to the motor elements of the hydraulic motor a hydraulic pressure differential to displace the motor elements radially inwardly and withdraw the associated driving means from contact with the cam faces of the cam ring whereby the cam ring can rotate freely, said free-run means including means for preventing said fluid pressure means from releasing said brake means until said pressure differential has been developed to condition said motor elements and associated driving means to move radially inwardly away from contact with said cam faces of said cam ring, an operator''s control for the motor wherein the free-run means includes means coupled to the operator''s motor control for ensuring that the free-run means can only be actuated when the motor control is in the off position.

12. In a system for operating and controlling a winding gear driven by a rotary hydraulic motor, driving means for selectively supplying hydraulic fluid to said rotary hydraulic motor to rotate said hydraulic motor and said winding gear, said driving means including first supply means for supplying hydraulic pressure fluid to said hydraulic motor, normally applied brake means for said winding gear, fluid pressure means including fluid communication means for releasing said brake means, free-run means including fluid communication means for applying to a portion of the hydraulic motor a hydraulic pressure to allow said hydraulic motor to rotate freely without load, said free-run means including second supply means for supplying said hydraulic motor portion, said second supply means including a source of hydraulic fluid separate from the source of hydraulic fluid for said drive means, said free-run means including means for preventing said fluid pressure means from releasing said brake means until said hydraulic pressure has been supplied to said portion of said motor to condition said motor to rotate freely without load.

13. The invention of claim 12 wherein said rotary hydraulic motor is reversible and said hydraulic motor drive means further includes a motor control valve for controlling flow of hydraulic fluid to said hydraulic motor for driving rotation thereof, said control valve having a first position for supplying fluid to cause said motor to rotate in a first direction, a second position for supplying fluid to cause said motor to rotate in the reverse direction, and a neutral position in which fluid flow to and from said hydraulic motor is blocked and a hydraulic fluid lock is created which retards rotation of said hydraulic motor in either of said first or reverse directions.

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