US3801071A

US3801071A - Towing winch control system

Info

Publication number: US3801071A
Application number: US00295758A
Authority: US
Inventors: C Barron
Original assignee: BYRAN JACKSON Inc
Current assignee: Varco International Inc; BYRAN JACKSON Inc
Priority date: 1972-10-06
Filing date: 1972-10-06
Publication date: 1974-04-02
Anticipated expiration: 1991-04-02

Abstract

A towing winch control system in which the winch for the towing cable is driven through a slipping clutch to apply a substantially constant tension to the towing cable, and a position sensor and a tensiometer are operated to control the length of the tow cable between the towing winch and the object being towed and to limit the load on the cable to prevent parting of the cable.

Description

United States Patent Barron [451 Apr. 2, 1974 TOWING WINCH CONTROL SYSTEM 3,596,070 7 1971 McCool 254 173 R x 4 82 9 1 [75] Inventor: Charles D. Barron, Huntmgton g gz J gs? I i: Beach, m- 3,612,486. 10 1971 Martin 254 172 17 1 Assigneer y J g Beach, FORElGN PATENTS 0R APPLICATIONS Cahf- 1,159,229 11/1956 Germany 254 172 22 il O 6 1972 1,138,908 11/1959 Germany 254/173 864,182 3/1961 Great Britain... 254/173 [211 App]. No.: 295,758 646,279 4/1933 Germany 254/173 Related US. Application Data 1,294,078 2/1969 Germany 254/173 [63] Continuation of Ser. No. 110,695, Jan. 28, 1971, primary Examiner RichaI-d Aegerter abandoned Assistant ExaminerH. S. Lane Attorney, Agent, or Firm-Donald W. Banner [52] U.S. C1. 254/173 R, 254/187 R [5 Int. .1 [58] Field of Search 254/172 R, 173 B, 185 R, 1

v A towmg wmch control system in WhlCh the wlnch for 254/173 R, 187 R, 175.7

the towlng cable 1s dr1ven through a slipping clutch to [561 121123 222 21221 9,:-

e, a a pos sen a 10m e UNITED STATES PATENTS ated to control the length of the tow cable between 2,275,953 Fl'lSCh the towing winch and the object being towed and to 2,443,028 6/1948 Edwards'" 254/172 limit the load on the cable to prevent parting of the 3,189,196 6/1965 Carl et a1. 214/14 cable 3,289,967 12/1966 Robinson 254/172 X 3,507,478 4/1970 15 Claims, 6 Drawing Figures Lewis 254/1757 PATENTEBAPR 21am 3.801.071

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PATENTED APR 2 I974 SHEET 3 BF 4 INVENTOR (H/45665 0. e eeo/v TOWING WINCH CONTROL SYSTEM This application isa continuation of application Ser. No. 110,695, filed Jan. 28, 1971, now abandoned.

BACKGROUND OF THE INVENTION The towing of a vessel to sea, such as well drilling barges, cargo barges, or, indeed any vessel, by a tug or other towing vessel, poses problems which are difficult of solution, Heretofore, the towing cable by which the towing vessel tows the towed vessel has been relied upon to compensate for changes in load on the cable due to changes in tidal, wave, or wind action on the vessels, and, as a result, an extremely long run of cable or line has been employed. The cable sags between the vessels, generally beneath the water and provides a long arcuate cable section which can be more or less tensioned as the towing vessel and the towed vessel experience different influences of tide, waves, or wind, or combinations thereof.

Such long tow lines or cables make control of the towed vessel very difficult, particularly when entering or navigating narrow channels or waterways. A heavy barge may require a length of tow line or cable on the order of one quarter mile, for example, to afford a safe bow in the line or cable, whereby the towing and towed vessels may react differently to different influences without parting the tow line or cable. A typical problem in this connection involves the opposite reactions caused by the towed vessels tending to slow down when on the trailing slope ofa wave and the towing vessel's tending to accelerate when picked up by the forward slope ofa wave. Such long tow lines or cables also produce a navigational hazard, particularly, when visibility is poor, and the pilot of another vessel may not be aware of the existence of the tow line, due to his inability to see the towed vessel, or, perhaps, either ves-' sel.

Ordinarily, the towing line or cable is on a towing winch and is played off as may be required by the relative conditions of the sea and the weight of the towed vessel. When desired, the winch is operated to pull in the line or cable to shorten the distance between the two vessels. However, if, due to wave, tide or wind influence on the vessels, the line is over loaded it may part, allowing the towed vessel to then drift free, with potentially dangerous results.

SUMMARY OF THE INVENTION The present invention provides a towing winch system which obviates the problems and hazards of the above-described towing practices.

More particularly, the present invention is a towing winch system which may be employed on a towing vessel to tow another vessel, or string of vessels, in a more closely adjacent relation than has been practical heretofore.

The towing winch system, in general, involves a winch adapted to be driven by a power source through a clutch which is capable of constantly slipping to apply a substantially constant tension on the towing line or cable. When the load on the line or cable increases above a pre-set capacity. the line or cable will be stripped from the winch, but when, the tension is thereafter reduced the line or cable will be rewound by the winch until the towed vessel is in the pre-selected spaced relation to the towing vessel.

In accomplishing the foregoing, a position sensor and a tensiometer are engaged with and operated by the tow line or cable to control the slip clutch so as to maintain the tension on the line or cable and to maintain the relative positions of the vessel, so long as different influences on the vessels permit the maintenance of the relative positions of the vessels, and to re-establish the tension on the line or cable and the relative positions of the vessels when the influences on the vessels, or either of them, permit.

Constant tension winches, driven by a fluid pressure actuated slip clutch are well known,'as exemplified in United States Letters Patent No. 3,373,972, dated March 19, 1968. Preferably, however,'to effect better cooling of the slip clutch with resultant improved efficiency, the clutch may be cooled as disclosed in the pending application for United States Letters Patent of C. D. Barron, Ser. No. 19,601, filed Mar. 16, 1970. The position sensor referred to above is adapted to cause a change in the fluid pressure acting on the slip clutch, and is preferably made in accordance with the disclosure of the pending application for United States Letters Patent of C. D. Barron, Ser. No. 19,564, filed Mar. 16, 1970.

This invention possesses many other advantages, and has other purposes which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed. description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims. In this connection, while the invention is herein disclosed as being incorporated in a towing winch system, it will be understood that the invention is applicable to other dynamic systems in which the tension on a line and the position of a line must be controlled or adjusted to prevent overloading of the line and to reposition a load in response to changes in load condition.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective, generally illustrating a towing vessel and a towed barge to which the towing winch control system of the invention is applied;

FIGS. 2a and 2b, together constitute a diagrammatic illustration of the towing winch control system, FIG. 2b constituting a downward continuation of FIG. 2a;

FIG. 3 is a longitudinal section through a computing relay or pressure transmitter employed to vary the drive of a slip clutch in response to variations in the load conditions on the towing winch line;

FIG. 4 is a longitudinal section through a line position sensing device for varying a pressure signal supplied to the computer of FIG. 3, in response to changes in position of the towing winch line; and

FIG. 5 is a view partly in elevation and partly in longitudinal section, showing a slip clutch assembly for driving the towing winch.

DESCRIPTION OF THE PREFERRED EMBODIMENT As seen in the drawings, with reference first to FIG. 1, a towing vessel or tug boat V isv shown as having a towing winch W from which a tow cable or line L extends sternward for connection to a towed vessel or barge B.

While a rock barge is shown as illustrative, it will be understood that the problem of overload on. a towing line L exists in any similar situation involving a towed vessel or barge, such as, for examples, an offshore well drilling platform, a disabled ship, or the like.

The towing vessel or tug is shown as having the winch W disposed above-deck, for clarity, and a suitable drive or motor. source M is shown below-deck, but as a practical matter, it may be preferred that the entire apparatus or any portion thereof be located below deck, with the cable or line L passing through a fairlead or guide at the stern of the vessel V.

More particularly, the illustrative drive M includes a suitable drive connection in the form of a chain adapted to effect rotation of a counter shaft 11 through a slip clutch assembly C, which, as is more particularly seen in FIG. 5 and described hereinafter, is adapted to transmit torque to the shaft 11 under the control of the control system of the invention, whereby to limit the tension on the line L and to adjust the relative positions of the towing vessel V and the barge B. Thus, a drive connection, say the illustrative chain drive 12 provides means for applying torque to the drum 13 of the winch W, whereby the line L will be pulled in if the selected line tension overcomes the load of the barge B, but the line L may be stripped from the drum 13 if the barge exceeds the pre-set line tension. Associated with the line L are sensing means TP, incorporated in the system and adapted, as will be later described, to sense the load or tension on the line L and to sense changes in position of the line L so as to effect control of the line.

Referring to FlG. 2a, the sensing means T? is gener ally shown 'to comprise a typical hydraulic tensiometer l5 and a position senser 16. The tensiorneter 15 is adapted to be applied to the line L in such a manner that the line engages and extends between a pair of spaced rollers 17 and 19 which are rotatable on shafts -l9 and 20, respectively, supported in a frame 21. A third roller 22 engages the line L between the rollers 17 and 18 to deflect the intermediate portion of the line, the roller 22 being carried on a shaft 23 which is mounted for movement relative to the frame 21, whereby such movementis applied to the hydraulic sensing unit 24, to produce a hydraulic signal the magnitude of which is a function of tension on the line L. Such devices 15 are well known and require no further description herein. An example of such a line tension no responsive device is the Tensiometer Model UD12 of Martin-Decker Corp., of Santa Ana, Calif. The position sensor unit 16 of the sensing means '1'? is more particularly illustrated in FIG. 4 and will be latter described.

ln order to control the speed 'at which the line L may change position, speed control means including a tachometer signal generator 25 is adapted to be driven by the winch drum 13 to supply a variable signal to an lsst n sqm a qi st 55a! QE..MQQ.1II1Q electro-pneumatic, transducer of Conoflow Corporation of Blackwood, NJ. The output from the hydraulic unit 15, the position sensor 16 and the transducer 26 are compared by computer means 27, the details of which are shown in FIG. 3, to control the clutch C, as will be more fully described below.

The clutch C, as best seenin FIG. 5, is associated with an end 37 of the counter shaft 11, and the drive chain 10 engages a sprocket 50 which is revolvable relative to the shaft end 37 on bearings 52. Affixed to the sprocket 50, is a disc 54 which is in turn affixed by fasteners 55 to the outer periphery of the back-up plate 56 of the slip clutch means C. i

This slip clutch means C includes an outer annular body 57 to which an annular flange 58 is connected by fasteners 59 in opposed relation to the plate 56. Internally thereof, the body 57 has a splined connection 60 with the outer periphery of an axially shiftable clutch pressure plate 61. Between the clutch plates 56 and 61 is a clutch friction disc 62 having friction facing 63 on opposite sides thereof and having, as at 64, a splined connection with a hub 65 which is disposed upon the shaft end 37 and is keyed thereto by a key 66. Thus, rotation from the sprocket 50 will be transmitted to the tensioning hoist shaft 11 when the slip clutch means C is engaged to transmit rotation from the clutch body 57 and its plates 56 and 61 to the friction disc 62.

Engagement of the slip clutch means C is accomplished by an annular expansible actuator tube 67 having an air inlet 68. The actuator tube 67 engages an annular body of insulating material 69 interposed between the tube 67 and the clutch pressure plate 61. Each of the clutch plates 56 and 61 has a number of annular, radially spaced and concentric coolant passages 56a and 61a to which a coolant is supplied to dissipate the heat of friction caused by slippage of the clutch C. These passages 56a and 610 are defined respectively between the clutch plates and a wear disc 56b carried by the plate 56 and a wear disc 61b carried by the plate 61, the friction material on the friction disc 62 being engaged with the wear discs 56b, 61b.

Such cooled, slip clutches are well known, and generally are provided with a coolant circulating system including a stationary coolant connector 71 through which coolant flows to and from a rotary connector 72 which is connected, as by fasteners 72a, to the clutch flange 58 and which has conduit means 73 for supplying coolant to the passages 56a and 61a, as well as conduit means for the return flow of coolant to the connector 71 and thenceto a heat exchanger. Preferably, in order to more effectively cool the clutch, it is constructed in accordance with the aforementioned application for patent. lnaddition, the rotary connector 72 provides a connection for air conduit means 74 which leads to the air inlet 68 for the clutch actuator tube 67 from a stationary air inlet fitting 75. As is well known, the torque transmitting capacity of such slip clutches varies withthe pressure of air in the actuator tube 67.

Thus, the tension applied to the line L will be determined by the magnitude of the air pressure supplied to the actuator tube 67 through the coupling 75 under the control of the computing relay 27, as will be more fully described below.

The preferred line position sensing unit 16, of the sensing meant TP, is shown in greater detail in FIG. 4, and is more specifically disclosed in the aforementioned pending patent application. It comprises an elongated housing 81 having at one end a closure or cap 82 and having at the other end an assembly which provides an air inlet or supply port 84, an outlet 85 for a controlled air pressure signal, a port 86 for bias pressure fluid, and a port 87 communicating with the atmosphere.

Included within the assembly are actuator means generally denoted at 88, fluid pressure responsive piston means 89 operatively connected to the actuator means 88, orifice means 90 operable in response to the application of fluid pressure to the piston means 89 and to the application of force from the actuator means 88 for opening and closing the orifice means 90, and combined inlet and outlet valve means 91 for controlling the flow of air from the supply port 84 to the output port 85 and for controlling the exhaust of air from the outlet port to the atmosphere through the port 87.

In general, it is the purpose of the position sensing pneumatic control device to regulate the output signal pressure to a constant value which is determined by the net force applied to the piston means 89, whereby the orifice means 90 is either opened or closed for a period sufficient to balance the piston means 89, so that the pressure drop through the orifice means 90 remains constant, resulting in a constant output signal pressure at the port 85 which leads to the computer relay 27, as will be later described.

More particularly, the actuator means 88 comprises a shaft 92 which extends longitudinally of the housing 81 and has an end 93 which extends axially from the end cap 82 through a suitable bearing 94 and a suitable seal 95. Disposed upon the shaft 92 within the housing 81 is a spring seat 96 having a reduced central section 97 on which is piloted the upper end of a coiled compression spring 98. The shaft 92 is threaded as at 99, and the spring seat 96 and the reduced pilot portion 97 thereof are complementally threaded, whereby rotation of the shaft 92 will effect longitudinal movement of the spring seat 96 on the shaft, since the seat 96 is held against rotation by a key 100 carried thereby and extending into a lateral slot 101 in the housing 81. At its inner end the spring 98 seats on a spring seat 103 having a reduced pilot portion 104. This spring seat 103 is connected by fasteners 105 to the circular upper body portion 106 of the piston 107 of the piston means 89, the seat 103 and the body 106 being held in axially spaced relation by tubular spacers 108 interposed therebetween and through which the fasteners 105 extend. The lower end of the shaft 92 extends through the seat 103 and is journalled in a bearing 109 which is mounted in a supporting spider 110 having circumferentially spaced openings 111 to accommodate the spacers 108, whereby the piston means 89 is axially movable.

The assembly also comprises, in addition to the spider 110, an annular spacer 112, an annular cylinder 113 for the piston 107 and an annular cylinder 114 which houses a piston 115, an annular body 116 containing the nozzle means 90, and an end member 117. The spider 110, spacer 112,

cylinders

113 and 114, annular body 116, and end member 117 are interconnected together and to the cylindrical body 81 by tiebolts or the like, requiring no illustration.

Between the spacer 112 and the cylinder 113 is clamped the outer marginal portion of a diaphragm 119, and between the cylinder 113 and the cylinder 114 is clamped the outer marginal portion of another diaphragm 120. Still another diaphragm 121 has its outer marginal portion clamped between the cylinder 114 and the annular body 116. In the illustrative embodiment. the body portion 106 of the piston 107, as

well as the piston 107 and the piston are interconnected by a stem 122 having an enlarged head 123 at one end which clamps the inner periphery of the diaphragm 121 against the adjacent portions of the piston 1 15, and a nut 124 is threaded onto the other end of the stem 122 to effectively clamp the piston 117, including its upper body portion 106, and the piston 107 together. The inner periphery of the diaphragm 119 is like-wise clamped between the upper body portion 106 and the piston 107, and the inner periphery of the diaphragm is clamped between the piston 107 and the piston 115. Thus, the piston means 89 comprises both the piston 107 and the piston 115. More particularly, the piston 107 has an enlarged portion 125 which is exposed to the pressure in a chamber 126 provided in the cylinder 113 between the diaphragms 119 and 120. The piston 115 is exposed to the pressure in a chamber 127 provided in the annular body 116 across substantially the entire cross-sectional area of the piston 115. Within the cylinder 114, the piston 115 is disposed in a chamber 128 which is vented to the atmosphere through radial ports 129.

lnterposed between the annular body 116 and the end member 117, and clamped at its outer margin is a double diaphragm assembly including an upper diaphragm 130 and a lower diaphragm 131 spaced apart by an outer material spacer 132 in which is formed one or more of the radial 'outlet ports 87, previously referred to, which communicate the space between the

diaphragms

130 and 131 with the atmosphere. In the annular body 116 above the upper diaphragm 130 is a chamber 134 and centrally of the body 116 is a threaded bore having therein a nozzle 136, the port through which communicates with the chamber 134, and the outlet of which is opposed by a nozzle seat 137 suitably carried by the lower end of the stem 122. Air is supplied to the chamber 134 and thence to the nozzle 136 from the supply port 84 through a passage 138 which extends through the margin of the

diaphragms

130 and 131 and the spacer 132 and connects with a passage 139 leading into the chamber 134. Disposed in the passage 139 is a flow restrictor 140 having a reduced passage therethrough'This flow restrictor is replaceable through an opening in thebody 116 which is closed by a threaded closure plug 141. At the outer side of the diaphragm 131 in the end member 127 is a chamber 142 which communicates with the output port 85. The output port 85 also communicates through a passage 143 with the chamber 127 in the body 116 below the diaphragm 121.

The inlet and outlet valve means 91, previously referred to, includes a valve seat 144 carried by a plate 145 below the diaphragm 131 and having a valve port 146 leading from the outlet chamber 142 into the space between the

diaphragms

130 and 131. A coiled compression spring 145a is provided beneath the plate 145 which applies a normal inward bias to the diaphragm 131 and to the outlet valve seat 144. A valve stem 147 is reciprocably mounted in a port 147a in the end member 117, which port leads from the inlet 84 to the outlet 85. The stem is normally biased inwardly by a coiled compression spring 148 which seats in a plug 149 in the end member 117 and acts inwardly on a spherical valve head 150 to bias the same against an inlet valve seat 151.

As previously indicated, the position sensing pneumatic control device functions to regulate the output signal pressure at the port 85 to a value which is proportional to sensed movement. Accordingly, the outer end 93 of the shaft 92, in the illustrative embodiment, has mounted thereon the sheave or roller 17 of the tensiometer'lS which is engaged by the cable or line L, to effect rotation of the shaft 92 in response to relative movement between the line L and the sensing device. Movement of the line L is transmitted to the shaft 92 to effect rotation of the latter in one direction or the other depending upon the direction of movement of the line L. It is apparent that rotation of the shaft 92 in one direction or the other will impose more or less compression on the spring 98 to provide more or less force acting on the piston means 89 which will either cause the nozzle seat 137 to close the nozzle 136 or to open the nozzle 136 for communication with the chamber 127, and hence the discharge or signal output port 85. Such spring force is opposed by the pressure of air in the chamber 127 acting on the cross-sectional area of the piston 115 and the pressure of fluid in the chamber 126 acting on the effective area of the piston 107. Thus, the fluid admitted through the port 86 to the chamber 126 may be supplied from a remote set point to quickly and easily calibrate the motion sensor, so that the signal output pressure is at a desired level, less than the input pressure, under the conditions that the shaft 92 is in the neutral or non-moving condition.

With the foregoing details in mind, the operation of the motion sensor is such that the spring 98 is operative to apply a variable force in a direction tending to move the piston means 89 variable force in a direction tending to move the piston means 89 downwardly. Opossing theforce derived from the actuator means is the force derived from the application of pressure from a remote set point to the bias or calibrating chamber 126, which pressure is effective over the area of the enlargement 125 of the piston means 89 to provide a force tending to move the piston means 89 upwardly. Also providing a force tending to move the piston means 89 upwardly is the pressure in the piston chamber 127 which acts upon the piston 115 of the piston means 89, the other side of the piston 115 being exposed to the atmosphere in the chamber 128.

The effective signal outlet pressure in the piston chamber 127 is a function of the reduction in the inlet pressure caused by the passage of air from the inlet 84 through the flow restrictor 140 into the pilot pressure chamber 134 and the reduction in pressure resulting from the passage of air from the pilot pressure chamber 134 through the orifice means 136, as indicated by the arrows, into the piston chamber 127. When the device is in the condition shown in F IG. 4, the effective signal outlet pressure at the outlet 85 is the same as that in the piston chamber 127, and under the condition shown the pressure drop from the inlet 84 to the outlet 85 will remain constant, unless theforce derived from the actuator means 88 is varied or the force derived from the remote set point pressure is varied.

Assuming that the force derived from the actuator means tending to shift the piston means 89 downwardly is reduced, the net force acting on the piston means will cause the piston means to move upwardly, allowing greater flow from the pilot pressure chamber 134 into the piston chamber 127. Such action will result in an instantaneous decrease in the pilot pressure in the chamber 134. As a consequence, pressure applied to the diaphragm 131 and the force of the spring 145a will move the exhaust valve seat 144 upwardly and off of the end of the valve stem 147, to allow the exhaust of fluid pressure from the outlet chamber 142 and the piston chamber 127 through exhaust port 87, until the device again assumes the condition shown in FIG. 4 at which the exhaust valve port 146 is again closed. At this time, the pressureat the outlet will again be stabilized at a value determined by the fluid pressures acting on the actuator means 88 and the decreased spring force of the spring 98. A larger volume of air will flow past the orifice closure 137, and the signal outlet pressure will be at a lower value. 0

Assuming that the force derived from the actuator means tending to move the piston means 89 downwardly is increased, overcoming the effect of the signal outlet pressure in the chamber 127, then the orifice closure disc 137 will engage the end of the orifice means 136, thereby'shutting off the passage of air from the pilot pressure chamber 134 into the piston chamber 127. Under these circumstances, the pilot pressure in the pilot chamber 134 will build up, forcing the diaphragm and the diaphragm 131 downwardly, thereby unseating the valve 150, so that inlet pressure will transfer through port 147a of the inlet-outlet valve 91, resulting in an increase in the signal outlet pressure in the outlet chamber 142 and in the piston chamber 127 which will be effective to again condition the apparatus as shown in FIG. 4, so that the pressure at the outlet 85 again remains constant, but greater.

It will now be understood that variation of the remote set point pressure in the chamber 126 will have the same effect as variation of force derived from the actuator means. in other words, as the remote set point pressure is increased, the force tending tomove the piston means 89 upwardly will also be increased, but if the remote set point pressure is decreased, the force tending to move the piston means 89 upwardly will be decreased. The supply of air to the chamber 126 through the port 86 is shown in FIG. 20, as being via a conduit 860 leading from a suitable valve 86!: which controls the pressure derived from a source conduit 860 which leads from a suitable pressure source, not shown. The outlet port 85 is in communication with a conduit 85a which leads to the computer means 27, now to be described.

This computer means 27, as seen in FIG. 3, comprises a support 200 adapted to be mounted at a suitable location. Carried by the support 200 is an end cup 201 having a marginal flange 202 for connecting the cup 201 with an assembly which comprises a stack of

discs

203, 204, 205, 206 and 207 and a body 208, all connected at the outer peripheries by a suitable number of tie bolts, one of which is shown at 209. The disc 203 includes a rigid central section 203' and a flexible annular diaphragm 203" supporting the central section 203' and a flexible annular diaphragm 203" supporting the central section 203' within the disc 203. Similarly, each of the

discs

204, 205, 206 and 207 comprises a rigid central section 204 to 207' and an annular diaphragm 204" to 207". Intermediate, the discs 203 to 207 are annular, outer peripheral spacers 210 and central spacers 211. The outer spacers 210 are connected in the assembly by the tie bolts 209. The central spacers 211 are interconnected at the respective central sections 203' to 207' by a pin 212 having a head 213 at its lower end and a nut 214 at its upper end for clamping the piston sections and central spacers together.

Fluid under pressure, say air, is supplied to the computer means 27 above and below the stack of diaphragms and between the diagrams from various sources, whereby to provide an output pressure signal which is a function of the various input signals and the constant force of an adjustable coiled spring K which is disposed in the cap 201 and seats, at one end, on a seat 215 above the disc section 203' and at the other end on a spring seat 216 carried by an axially shiftable adjuster pin 217. The pin 217 is shiftable by an adjuster screw 218 threaded in a nut 219 which is suitably affixed to the support 200. Below the disc 207 is another coiled spring K which seats at one end in a seat 208 and engages at its other end beneath the disc section 207 in opposition to the spring K. Thus, the spring K is adjustable to provide a selected force on the stacked disc sections 203 to 207, determined by the relationship between springs K and K.

Air pressure is supplied to a chamber P1 in the cup 201, from the position sensor 16 via conduit 85a, by suitable means, such as an inlet fitting 220, to provide a downward force on the effective piston area of the central section 203' of disc 203. In order to increase the magnitude of the force derived from air pressure supplied to the computer 27 from the position sensor 16 via conduit 85a, a branch conduit 85b leads to a chamber P2 defined between the diaphragms 203" and 204", say through a pressure inlet 221, so that such pressure also acts downwardly on the effective annular piston area of the central section 204 of the disc 204, which extends radially beyond the spacer 211 thereabove.

Below the annular piston area of the disc section 204 is a chamber R having an inlet 222 to which pressure fluid is supplied, as will be later described, at a value determined by the computer 27, the pressure in chamber R acting upwardly on the effective annular piston area of the disc section 204 in opposition to the downward force derived from pressure in the chambers P1 and P2.

Between the

discs

205 and 206 is defined a pressure chamber S to which air is supplied through an inlet 223 via a conduit 260, at a pressure determined by the speed of rotation of the drum 13, under the control of the electro-pneumatic transducer 26, previously referred to. The disc section 206 provides an annular piston area projecting radially outwardly of the spacer 211 thereabove, this piston area being responsive to pressure in chamber S to provide a downward force. Below the disc section 206 is another chamber T to which air is supplied via a port 224 at a pressure determined, as will be later described, by the tension on the line L. Such pressure acts upwardly on the effective annular piston area of the disc section 206.

Below the disc 207, and in the body 208, is a chamber X which constitutes an output chamber communieating with an outlet port 225 via porting 226. The pressure in the chamber acts upwardly on the lower disc section 207, and this pressure is derived from on inlet conduit 27a (FIG. 2a) connected to an inlet port 227, under the control of the computer.

Interposed between the body 208 and an end member 228 having the

ports

225 and 227 therein, and clamped at its outer margin is a double diaphragm assembly 229 including an upper diaphragm 230 and a lower diaphragm 231 spaced apart by an outer marginal spacer 232 in which is formed one or more radial outlet ports 232a, which communicate the space between the diaphragms 230 and 231 with the atmosphere. In the body 208 above the upper diaphragm 230 is a threaded bore having therein a nozzle 236, the port through which communicates with the chamber X, and the outlet of which is opposed by a valve head 237 suitably carried by the lower end of the stem 212. Air is supplied to the chamber 234 and thence to the nozzle 236 from the supply port 227 through a passage 238 which extends through the margin of the diaphragms 230 and 231 and the spacer 232 and connects with a passage 239 leading into the chamber X. Disposed in the passage 239 is a flow restrictor 240 having a reduced passage therethrough. This flow restrictor is replaceable through an opening in the body 208 which is closed by a threaded closure plug 241. At the underside of diaphragm 231 in the end member 228 is a chamber 241 which communicates with the output port 225. The output port 225 also communicates through the passage 226, previously referred to, with the chamber X in the body 208 below the piston or disc section 207'.

Inlet and outlet valve means are provided to control the admission of fluid from the inlet 227 to the chamber 242 and the exhaust of such fluid through the vent port 232a. This valve means includes a valve seat 244 carried by a plate 245 below the diaphragm 231 and having a valve port 246 leading from the .outlet chamber 242 into the space between the diaphragms 230 and 231. A coiled compression spring 245a is provided beneath the plate 245 and applies a normal upward bias to the diaphragm 231 and to the outlet valve seat 244. A valve stem 247 is reciprocably mounted in a port 247a in the end member 228 which port leads from the inlet 227 to the outlet chamber 242. The stem is normally biased inwardly by a coiled compression spring 248 which seats in a plug 249 in the end member 228 and acts inwardly on a spherical valve head 250 to bias the same against an inlet valve seat 251.

As previously indicated, the computer means functions to regulate the output signal pressure at the port 225 to a value which is proportional to;load on or position of the line L, as well as speed of the drum 13, and in addition, the computer may be adjusted to modify the output pressure by varying either the effective constant force of spring K or the reference set point pressure in the chamber R. Thus, as will be understood, the output pressure in chamber X is determined by the various pressures in the various chambers P1, P2, R, S and T, acting on the various piston areas of the discs 203 to 207. The equation may be stated:

sition sensor 16 tending to close the nozzle 236, R is the.

pressure derived from a reference pressure source tending to open the nozzle 236, S is the pressure derived from the speed of the drum 13 tending to close the nozzle 236, T is the pressure derived from the tension sensing means 15 tending to open the nozzle 236, and K is the spring constant.

The effective signal outlet pressure in the outlet chamber 242 is a function of the reduction in the inlet pressure caused by the passage of air from the inlet 227 through the flow restrictor 240 into the pilot pressure chamber 234, and the reduction in pressure resulting from the passage of air from the pilot pressure chamber 234 through the orifice means 236, as indicated by the arrows, into the pressure chamber X. When the device is in the condition shown in FIG. 3, the effective signal outlet pressure at the outlet 225 is the same as that in the chamber X, and, under the condition shown, the pressure drop from the inlet 227 to the outlet 225 will remain constant, unless the force derived from any of the position sensing means TP, the tachometer 25, or the reference pressure is varied, and, accordingly, as will be later more fully described, the actuating pressure supplied to the clutch C will remain constant.

Assuming that the force tending to shift the stacked disc sections causes the valve head 237 to move upwardly allowing greater flow from the pilot pressure chamber 234 into the chamber X, such action will'result in a decrease in the pilot pressure in the chamber 234. As a consequence, pressure applied to the diaphragm 231 and the force of the spring 145a will move the exhaust valve seat 244 upwardly and off of the end of the valve stem 247 to allow the exhaust of fluid pressure from the outlet chamber 242 and the chamber X through exhaust port 232a between the diaphragms 230 and 231, until the device again assumes the condition shown in FIG, 3 at which the exhaust valve port 246 is again closed. At this time, the pressure at the outlet 255 willagain be stabilized at a lower value, determined by the change in forces acting on the stack of disc sections 203' to 207'.

Assuming that the net force tending to move the stacked discs 203' to 207 downwardly is increased, overcoming the effect of the signal outlet pressure in the chamber X, then the orifice valve 237 will close the orifice means 236, thereby shutting off the passage of air from the pilot pressure chamber 234 into the chamber X. Under these circumstances, the pilot pressure in the pilot chamber 234 will build up, forcing the diaphragm 230 and the diaphragm 231 downwardly, thereby unseating the valve 250, so that inlet pressure will transfer through port 247a of the inlet-outlet valve means, resulting in an increase in the signal outlet pressure in the outlet chamber 241 and in the chamber X, which will be effective to again condition the apparatus as shown in FIG. 3, so that the pressure drop therethrough again remains constant, but greater, since there is less flow through'the orifice means 236.

The conduit 300 leads from the outlet port 225 of the computing relay 27 to the control pressure inlet 301 of a pressure controller C1 of a conventional type adapted to control the pneumatic pressure at an outlet 302 suppliedfrom asuitable source (not shown) through an inlet 303, whereby, as will be later described the slip clutch C is adapted to apply a controlled constant I torque to the drum 13 which is a function of the output signal pressure of the computer or transmitter means 27.

More particularly, the controller C1 may be Model 50 Controller of Moore Products Co., of Spring House, Pennsylvania or a Model 2516 Controller of Fisher Governer Company of Marshalltown, Iowa, as examples, the controller, generally, shown in FIG. 2b, being the latter and more specifically illustrated in Bulletin D-2506A of that company.

The controller C1 is supplied a reference pressure at an inlet 304 from a conduit 305 connected to a source (not shown) by a regulator valve 306, the same reference pressure being supplied to the reference chamber R of the computer or transmitter means 27. This reference pressure is admitted to a bellows 307 of the controller which cts downwardly on a plate 308. Pressure supplied to the inlet 301 from the computer 27 causes an increase in acts in a bellows 309 which is opposed to the bellows 307 and acts upwardly on the plate 308. The position of the plate 308 relative to a nozzle 310 to which controlled fluid pressure is supplied from the source inlet 303, is determined by the difference in pressures in the bellows 307 and 309. If the output pressure from the computer means 27 increases, the pressure increases in bellows 309 causing the plate 308 to move closer to the nozzle 310, restricting flow through the nozzle to cause an increase in the pressure in a chamber 31 1 ofa control valve 312, causing an increased downward force on a diaphragm assembly comprising spaced diaphragms 313 and 314, which carries a valve seat 315, the passage through which communicates with the atmosphere through a port 316 between the diaphragms 313 and 314. The valve seat 315 engages and pushes downwardly, under the circumstances now being described, on an inlet and outlet valve having a head 317 for closing the exhaust passage through the valve seat 315 and a head 318 which is moved away from a seat 319 to allow increased supply pressure into the valve outlet chamber 320 which acts on the diaphragm 314 until the valve seat 315 is again moved upwardly to allow return upward movement of the inlet-outlet valve head 318 towards its seatv During the same time, pressure is increasing in the chamber 320, such pressure is supplied to the outlet 302, and, thus, to the clutch C, as well as to an adjustable proportioning valve 321 and, depending on the adjustment of the latter, to an adjustable re-set control valve 322 which controls the build up of pressure in a bellows 323. This bellows 323 acts downwardly on the plate 308 tending to move the latter away from the nozzle 310 to decrease pressure at the outlet 302 and in control valve chamber 320, and is opposed by the upward action of a bellows 324 to which pressure is supplied from the valve 322 at a slower rate, depending on the adjustment of the valve 322, until the plate 308 is moved toward the nozzle to again increase pressure at the outlet 302 and in the valve chamber 320.

If a chamge in the system'causes a decrease in pressure at the inlet 301 to the controller C1, then, the reverse action will occur in the controller, the tendency being in either case to attempt to return to a preestablished, constant pressure at the outlet 302 which pressure is a function of the outlet pressure'from chamber X of the above-described computer means.

The outlet pressure from the controller means C l is supplied via a conduit 325 to cause actuation of the clutch C, but preferably a typical booster 326 is employed, whereby the actual pressure source (not shown) for the clutch includes an inlet to the booster 326 from a relatively high pressure source, and the pressure in conduit 32S acts on the usual pilot valve of the booster, so that the outlet 328 of the booster is at a greater pressure than the signal pressure from the controller C1. In addition, is preferred that a selector valve 329 be provided, so that the air connector of the clutch C may be connected either to the booster outlet 328 or, alternatively, to a separate source conduit 330 including a manualcontrol valve for operating the clutch C independently of the control system.

A second controller means C2 is employed, as previously indicated, to vary the pressure supplied to the chamber T of the computer or transmitter means 27, as a function of line tension, and, thus, to vary the output signal pressure from the computer according to the above equation for the pressure of the chamber X.

Accordingly, leading from the hydraulic load cell 24 of the tensiometer 15 of the sensing means TP, to the controller means C2 is a conduit 331 through which a hydraulic pressure signal depending upon load or tension of the line L is transmitted to the controller C2 to control the pneumatic pressure supplied to the controller outlet 332 from an inlet 333. This controller C2, for example, may be the Model 4151 remote set proportional controller or transmitter of the Fisher Governor Company, as illustrated in Bulletin D415OC.

In the illustrative controller C2 is a hydraulic pressure responsive means in the form of a Bourdon tube 334, an increase in pressure in which forces a plate 335 toward an exhaust nozzle 336 of the control valve means 337, and a decrease in pressure in which moves the plate 335 away from the nozzle 336 to vary the pressure in the valve chamber 338 as the sensed hydraulic pressure signal is varied to cause a decrease or increase in the outlet pressure at outlet 333 and in the chamberT of the computer means 27, whereby the net result is the application ofa pressure to clutch C dependent upon the tension on line L.

The control valve means 337 is similar to the control valve means 312 previously described, and includes a diaphragm assembly comprising a diaphragm 339 exposed to pressure in the chamber 338 derived from the inlet 333, and a diaphragm 340 exposed to pressure in the valve chamber 341 which communicates with the outlet 332. This diaphragm assembly carries a valve seat 342, the passage through which communicates with the atmosphere through a port 343. A combined inlet and outlet valve has a head 344 engageable with the seat 342 to prevent exhaust of pressure from chamber 341 and a head 345 engageable with a seat 346, the passage through the latter communicating between the inlet 333 and the chamber 341.

Thus, if pressure in the Bourdon tube 334 is increased, due to an increase in tension on line L, the exhaust of pressure from chamber 338 will be restricted, causing an increase in pressure acting on the diaphragm 339, so that the valve seat 342 will engage valve head 344, preventing exhaust of air from the chamber 341 through the exhaust port 343, and, at the same time, the valve head 345 will be moved off of its seat, allowing an increase in pressure in chamber 341 which tends to return the diaphragm to'its original position.

Such increased pressure in the chamber 341 is conducted to an adjustable valve 347, and thence to a be]- lows 349 which acts on the plate 335 to move the same away from the nozzle 336 to effectively reduce the pressure in the chamber 338. Resisting such movement of the plate 335 is a bellows 350 having an inlet 351 to which a set point pressure is supplied from a remote point, such as a regulator valve 352 to which fluid is supplied from a suitable source (not shown), as for example, the same source as supplies reference pressure to the controller C1 and the computer or transmitter means 27.

Reduction in hydraulic signal pressure from the tensiometer 15 to the controller C2 will cause the plate 335 to move away from the nozzle 334 and a reduction in pressure in the control valve chamber 338, resulting in opening of the passage through valve seat 342 and reduction in the signal at outlet 332 and computer chamber T. This is to say that in the latter case, the operation of the controller is the reverse of that described above, as will be understood without need for further explanatlon.

For convenience, a gauge panel G is preferably provided, as seen in FIG. 2b, whereby to indicate the effective pressures determined by the position sensing means 16, the speed responsive means 26, and the line tension or load responsive means 15, as well as the reference pressure, the set-point pressure for controller C2, and the ultimate clutch actuating pressure supplied to the slip clutch C, respectively, such gauges being designated by the legends POS., REF, SPEED, LOAD, SET-POINT, and CLUTCH.

The POS, gauge is connected to the output of the position sensing means 16 by a conduit 400 which joins with the conduit 85a leading to the computer chambers P1 and P2. The REF. gauge is connected by a conduit 401 to the conduit 305 which leads to both the inlet 304 of controller C1 and the chamber R of the computer 27. The SPEED gauge is connected by a conduit 402 with the conduit 26a leading to the chamber S of the computer 27 from the drum speed responsive electro-pneumatic transducer means 26. The LOAD gauge is connected by a conduit 403 and a conduit 404 with the outlet 332 from the load or tension responsive controller means C2 and the chamber T of the computer 27. The SET-POINT gauge is connected by a conduit 405 between the set-point inlet 351 of the load responsive controller C2 and the supply regulator valve 352. The CLUTCl-l" gauge is-connected by a conduit 406 with the air inlet connector of the clutch C and the outlet of the selector valve 329.

From the foregoing, it is believed that the operation of the present invention clearly involves the controlling of the slip clutch drive means for the drum 13 to apply a tension to the line L controlled such that the tension is maintained substantially constant below a value established by the load SET-POINT pressure, but the air pressure supply to the clutch is, in the automatic mode, controlled by changes in load' or position sensed by the sensing means TP, whereby under added load, the line will be stripped from the drum in a predetermined ratio of feet of line to increased load until the line tension resumes the established value, and the line will then be wound on the drum to reposition the load relative to the towing vessel. The speed and extent of line movement in either direction is sensed by the speed

responsive means

25, 26 and the position sensing means 16 to vary the clutch operation to maintain a pre-established tension on the line to an established position at a controlled rate.

Thus, under all conditionsencountered by a towed vessel or barge B being towed by a towing vessel V, such as waves and wind or other forces, the barge may be positioned closely to the towing vessel without fear of parting the line L.

If it is assumed that a speed reference signal of 9 p.s.i. is supplied to the computer chamber S when the drum is static, the reference pressure of 5 p.s.i. is supplied to the inlet 304 of controller Cl and to the chamber R of the computing relay 27, the controller C2 supplies a load orv tension reference pressure to the chamber T of 9 psi. at a predetermined line tension, and the position sensor 16 supplies a position signal of 5 p.s.i. to the chambers P1 and P2 of the computer 27, then the equation representing the computer output pressure is Under these conditions, the output signal to the inlet 301 of controller C1 from the computing relay is the same as the reference input pressure signal at the inlet 304, and, therefore, the clutch actuating signal pressure transmitted to the booster 326 remains constant, and the line tension caused by the torque transmitted by the clutch C remains constant.

Now, if the load on line L decreases, due to the tendency of the towed vessel and the towing vessel to move towards one another, for example, so that the load signal pressure derived from the load sensor and the controller C2 is reduced to 8 p.s.i., then the equation reads:

Under these conditions, the output signal to the inlet 30] of the controller Cl is 6 p.s.i., but the reference pressure is 5 psi, resulting in an increase in the pressure inthe chamber 311 of the control valve 312 and a resultant increase in the pressure in the outlet 302 of the controller Cl and in the pressure applicable to the clutch actuator to tend to wind in the line. Conversely,

- if the load on the line increases, the clutch actuating signal pressure will be decreased Under these conditions, however, line position changes are reflected in the pressure signal derived from the position sensor operated controller C2, so that as the line moves in or out the effective pressure in the chamber P1 and P2 of the computer 27 is varied by the position sensing means 16, and the effective pressure in the chamber S of the computer is varied by the speed of drum movement, resulting in a control system which is capable of maintaining position of the towed vessel, under constant line tension conditions, but enables the line to be stripped from the drum in a predetermined ratio of feet of line to increased load on the line above the set-point. Indeed, the system can be at equilibrium when subjected to loads on the line different than the load which the system is adjusted for by the set-point. The system automatically returns the line to a preestablished position when the line is subjected to the pre-established tension.

I claim:

1. ln a winch system including a winch drum having a line thereon connectable to a load, drive means for driving said drum to wind said line on said drum, to hold said line, and to allow said line to be stripped away from said drum, said drive means including a continuouslyoperable slip clutch having continuously variable actuator means operable to adjust the torque transmitted to said drum by said drive means, settable control means for establishing a predetermined line position at a preselected line tension, said control means comprising: line position sensing means responsive to the deviation of said line away from said predetermined line position for producing an output signal proportional to saiddeviation, line tension sensing means responsive to the tension in aid line for producing an output signal proportional to the deviation of said tension from said preselected tension, said control means including computer means comprising means for receiving both said output signals and producing a continuously variable clutch control signal which is a function of the integration of said output signals, and means for varying said actuator means as a function of said clutch control signa] to adjust said actuator means for causing said line to be stripped away from, held on, or returned to said drum in response to said clutch control signal to continuously control the deviation of said line from said predetermined line position in proportion to said deviation of the tension in said line.

2. In a winch system as defined in claim 1, speed sensing means operable by said drum, said control means including means operable by said speed sensing means to adjust said actuator means and control the speed of movement of said drum.

3. In a winch system as defined in claim 1, said actuator means comprising an air pressure responsive device, a source of air connected to said device, and said control means varying the supply of air to said device from said source.

4. In a winch system as defined in claim 1, said control means comprising means for producing a variable air signal pressure to adjust said'actuator means.

5. In a winch system as defined in claim 4, speed responsive means operable by said drum to adjust said air signal pressure to limit the speed of movement of said drum.

6. In a winch system as defined in claim 1, said line tension sensing means comprising tensiometer means engaged with said line, said position sensing means engaged with said line, and said control means comprising computer means for receiving said output signals and producing a'clutch control signal at a constant value determined by the difference between said output signals.

7. In a winch system as defined in claim 6, speed responsive means to produce an output signal determined by the speed of movement of said line, said computer means receiving said output signal of said speed responsive means and being operable to produce a clutch control signal determined by the difference between the sum of said output signal of said position sensing means and said output signals of said speed responsive means, and the output signal of said tensiometer means.

8. In a winch system as defined in claim 1, said line tension sensing means comprising tensiometer means engaged with said line, said position sensing means engaged with said line, said control means comprising computer means for receiving said output signals and producing a clutch control signal at a constant value determined by the difference between said output signals, and speed responsive means operable upon winding of line on said drum and stripping of line from said drum to produce a speed responsive output signal, said computer means receiving the latter output signal and adding the same to said position control signal in producing said clutch control signal.

9. In a winch system as defined in claim 1, said line tension sensing means comprising tensiometer means engaged with said line, said position sensing means engaged with said line, and said control means comprising computer means for receiving said output signals and producing a clutch control signal determined by the difference between said output signals, said control means including a pressure controller operable in re sponse to said output signal of said tensiometer means to maintain said output signal determined by the load on said line at a constant value.

10. In a winch system as defined in claim 1, said line tension sensing means comprising tensiometer means engaged with said line, said position sensing means engaged with said line, and said control means comprising computer means for receiving said output signals and producing a clutch control signal determined by the difference between said output signals, said control means including a pressure controller operable in response to said output signal of said tensiometer means to maintain said output signal determined by the load on said line at a constant value, and speed responsive means operable upon winding and unwinding ofline on said drum to produce a speed responsive output signal, said computer means receiving the latter output signal, said speed responsive output signal being added to said output signal from said position sensing means by said computer means in producing said clutch control signal.

11. In a winch system as defined in claim 1, said actuator means comprising an air pressure responsive device, a source of air connected to said device, said control means varying the supply of air to said device from said source, said control means comprising a pressure computer for receiving variable input pressure signals representative of load on said line, the deviation of said line, and a reference pressure, and said computer producing an output pressure signal determined by the equation X 2? R T,

where X is the computer output signal pressure, P is the input pressure signal determined by the deviation of said line, R is the reference input pressure signal, and T is the input signal pressure determined by load on said line, said tension sensing means sensing the load on said line and said position sensing means sensing the deviation of said line and supplying said variable input pressure signals to said computer means representative of load on said line and the position of said line, and means for supplying a selected reference signal pressure to said computer means.

12. In a winch system as defined in claim 11, said computer means comprising a control valve assembly having an air inlet, an air outlet, and an exhaust port, and valve means for controlling the flow of air from said inlet to said outlet and said exhaust port to maintain said output pressure signal substantially constant at a selected pressure.

13. In a winch system as defined in claim 1, said clutch actuator means comprising an air pressure responsive device, a source of air connected to said device, said control means varying the supply of air to said device from said source, said control means comprising a pressure computer for receiving variable input pressure signals representative of load on said line, the deviation of said line, and a reference pressure, and said computer producing an output pressure signal determined by the equation where X is the computer output signal pressure, P is the input pressure signal determined by the deviation of said line, R is the reference input pressure signal, and T is the input signal pressure determined by load on said line, said tension sensing means sensing the load on said line and said position sensing means sensing the deviation of said line and supplying said variable input pressure signals to said computer means representative of load on said line and the position of said line, means for supplying a selected reference signal pressure to said computer means, and controller means for receiving the computer output signal and variably transmitting a constant output signal to control said clutch of a magnitude determined by said computer output signal.

14. In a winch system as defined in claim 1, said clutch actuator means being pneumatically operable, said line tension sensing means comprising hydraulic load sensing means for producing a hydraulic pressure signal determined by the load on said line, controller means having an air inlet, an air outlet, and control valve means operable by said hydraulic pressure signal to cause a constant output pressure signal at said outlet, said sensing means also comprising pneumatic sensing means operable in response to deviation of said line and including an air inlet, an air outlet, and control valve means operable to cause a constant output pressure signal at the latter outlet, additional controller means having an air inlet, an air outlet, and control valve means operable to cause a constant output pressure signal at the last-mentioned outlet, pneumatic computer means having an air inlet, an air outlet and control valve means for maintaining a constant output pressure signal at the outlet of said computer means at a pressure determined by a comparison of said output pressure signals from said controllers, and means for put pressure signal from said computer means.

Patent No.

Inventor(s) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3,801,071 Dated April 2, 1974 Charles D. Barron It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column Column Column [SEAL] line 7, "to" should be --at--.

line 40, "played" should be --payed--.

line 18, after "1970" insert now U.S. Patent No.

3,648,814, issued March 14, l972--.

line 6, "117" should be --l07--.

line 7, "107" should be --ll5-.

line 5, "X" should be --234--.

line 18, "145a" should be --245a--.

line 23, "333" should be --332--. 1

Signed and Scaled this Tenth Day Of October 1978 A ttest:

DONALD W. BANNER RUTH C. MASON Attesting Officer Commissioner of Patents and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 01,071 Dated April 2, 19'!- Inventor(s) Charles Barron It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Front Page, Assignee: "Byran Jackson, Inc. should read Byron Jackson Inc. Long Beach, Calif.

Signed and Sealed this A rtest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (ummisxioner ofPare'nts and Trademarks

Claims

1. In a winch system including a winch drum having a line thereon connectable to a load, drive means for driving said drum to wind said line on said drum, to hold said line, and to allow said line to be stripped away from said drum, said drive means including a continuously operable slip clutch having continuously variable actuator means operable to adjust the torque transmitted to said drum by said drive means, settable control means for establishing a predetermined line position at a preselected line tension, said control means comprising: line position sensing means responsive to the deviation of said line away from said predetermined line position for producing an output signal proportional to said deviation, line tension sensing means responsive to the tension in aid line for producing an output signal proportional to the deviation of said tension from said preselected tension, said control means including computer means comprising means for receiving both said output signals and producing a continuously variable clutch control signal which is a function of the integration of said output signals, and means for varying said actuator means as a function of said clutch control signal to adjust said actuator means for causing said line to be stripped away from, held on, or returned to said drum in response to said clutch control signal to continuously control the deviation of said line from said predetermined line position in proportion to said deviation of the tension in said line.

4. In a winch system as defined in claim 1, said control means comprising means for producing a variable air signal pressure to adjust said actuator means.

6. In a winch system as defined in claim 1, said line tension sensing means comprising tensiometer means engaged with said line, said position sensing means engaged with said line, and said control means comprising computer means for receiving said output signals and producing a clutch control signal at a constant value determined by the difference between said output signals.

9. In a winch system as defined in claim 1, said line tension sensing means comprising tensiometer means engaged with said line, said position sensing means engaged with said line, and said control means comprising computer means for receiving said output signals and producing a clutch control signal determined by the difference between said output signals, said control means including a pressure controller operable in response to said output signal of said tensiometer means to maintain said output signal determined by the load on said line at a constant value.

10. In a winch system as defined in claim 1, said line tension sensing means comprising tensiometer means engaged with said line, said position sensing means engaged with said line, and said control means comprising computer means for receiving said output signals and producing a clutch control signal determined by the difference between said output signals, said control means including a pressure controller operable in response to said output signal of said tensiometer means to maintain said output signal determined by the load on said line at a constant value, and speed responsive means operable upon winding and unwinding of line on said drum to produce a speed responsive output signal, said computer means receiving the latter output signal, said speed responsive output signal being added to said output signal from said position sensing means by said computer means in producing said clutch control signal.

11. In a winch system as defined in claim 1, said actuator means comprising an air pressure responsive device, a source of air connected to said device, said control means varying the supply of air to said device from said source, said control means comprising a pressure computer for receiving variable input pressure signals representative of load on said line, the deviation of said line, and a reference pressure, and said computer producing an output pressure signal determined by the equation X 2P - R - T, where X is the computer output signal pressure, P is the input pressure signal determined by the deviation of said line, R is the reference input pressure signal, and T is the input signal pressure determined by load on said line, said tension sensing means sensing the load on said line and said position sensing means sensing the deviation of said line and supplying said variable input pressure signals to said computer means representative of load on said line and the position of said line, and means for supplying a selected reference signal pressure to said computer means.

13. In a winch system as defined in claim 1, said clutch actuator means comprising an air pressure responsive device, a source of air connected to said device, said control means varying the supply of air to said device from said source, said control means comprising a pressure computer for receiving variable input pressure signals representative of load on said line, the deviation of said line, and a reference prEssure, and said computer producing an output pressure signal determined by the equation X 2P - R - T where X is the computer output signal pressure, P is the input pressure signal determined by the deviation of said line, R is the reference input pressure signal, and T is the input signal pressure determined by load on said line, said tension sensing means sensing the load on said line and said position sensing means sensing the deviation of said line and supplying said variable input pressure signals to said computer means representative of load on said line and the position of said line, means for supplying a selected reference signal pressure to said computer means, and controller means for receiving the computer output signal and variably transmitting a constant output signal to control said clutch of a magnitude determined by said computer output signal.

14. In a winch system as defined in claim 1, said clutch actuator means being pneumatically operable, said line tension sensing means comprising hydraulic load sensing means for producing a hydraulic pressure signal determined by the load on said line, controller means having an air inlet, an air outlet, and control valve means operable by said hydraulic pressure signal to cause a constant output pressure signal at said outlet, said sensing means also comprising pneumatic sensing means operable in response to deviation of said line and including an air inlet, an air outlet, and control valve means operable to cause a constant output pressure signal at the latter outlet, additional controller means having an air inlet, an air outlet, and control valve means operable to cause a constant output pressure signal at the last-mentioned outlet, pneumatic computer means having an air inlet, an air outlet and control valve means for maintaining a constant output pressure signal at the outlet of said computer means at a pressure determined by a comparison of said output pressure signals from said controllers, and means for supplying air to said clutch actuator means at a pressure determined by said output pressure signal from said computer means.

15. In a winch system as defined in claim 14, speed responsive means operable in response to rotation of said drum to produce an air pressure signal determined by the speed of said drum, said computer means receiving the last-mentioned pressure signal to adjust the output pressure signal from said computer means.