US 3568621 A
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Description (OCR text may contain errors)
0 United States Patent l 13,568,62l
 Inventor Masasuke Kawasaki 3,035,536 5/ 1962 Archer 114/77 21 1 pp No gigg f shdeu 70458 Primary Examiner-Trygve M. Blix v Filed g, 6 1970 Attorneys-Arnold, White & Durkee and John 6. Graham  Patented Mar. 9,1971
Continuation-impart of application Ser. No. 784,511, Nov. 19, 1968, abandoned, which is a confinuafiomimpm of .aBSTkACfl: A tugboat engages the stern of a barge using a amnion sen 714,558, Man 20 linkage which permits freedom of movement between the two 1968" gg haaia vessels for pitching, rolling, and/or heaving motions, but yet permits the tug to push and steer the barge. A large pin protruding from the bow of the tug extends into a vertical slot l 54] COUPLING ARRANGEMENT FOR ss s in the stern of the barge, the pin and slot being along or para]- 36 claims, 17 Drawing 8* lel to the centerlines of the vessels. Rigid struts connect the tug to the barge, these being positioned at angles with respect  11.8. CI. 114/235 to the vessels Swivel or hinge joints are used f connecting 1 21/00 the struts to the vessels to permit relative movement of the  Field of Search 1 14/235, 77 struts and vessels The pin may be cylindrical or curved at its sides, to permit rolling motion. The length of the pin and the  References cited depth of the slot may be such that slight fore-and-aft move- UNITED STATES PATENTS ment is permitted as ,would occur in pitch or roll. A wide 1,038,676 9/1912 Stevens 114/235 recess in the stem of the barge may be provided to accom- 2,984,202 5/1961 Lunde 1 14/235 modate the bow of the tug.
PATENTEDHAR 91ml $558, 21
I sum 10F 4 M. KAWASAK/ ATTORNEYS PATENIED mm 9 I97l 3; 568,621
' sum 2 or 4 I FIG. 7
M. KAWASAKI /4 INVISN'IUR.
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- ATTORNEYS PATENTEDHAR 9:97: 3.568.621
sum 3 or a M. Kawasaki INVE N TOR A LKOed 2 7 W 3 GUAM ATTORNEYS PATENTED MAR 9197:
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M Kawasaki Amvfd WM & Uwdee ATTORNEYS FIG/2a CGUPLING ARRANGEMENT lFGR VESSELS This application is a continuation-in-part of copending application Ser. No. 784,511, filed Nov. 19, 1968, now abandoned which in turn was a continuation-in-part of thencopending application Ser. No. 714,558, filed Mar. 20, 1968, now abandoned.
in the marine industry, it has been found that the use of tug and barge combinations for transporting cargos by water in many respects is economically superior to the use of selfpropelled vessels. However, tug and barge combinations have certain disadvantages in comparison to self-propelled vessels, from the viewpoint of technical and operational considerations. Specifically, when a tug tows a barge these disadvantages involve the additional resistance of the tug which is in the order of the resistance of the barge itself above a certain speed, and the inherent resistance characteristic of the design of barge forms, including the resistance of the skegs of the barge.
Considerable effort has been made in the marine industry to overcome the aforementioned technical and operational disadvantages of the tug and barge combination. The resistances have been eliminated successfully by placing the tug aft of the barge so that the barge is pushed rather than towed. Such an arrangement has proven satisfactory in relatively calm water. It has not, however, been found reliable in rough water, due to the unsatisfactory coupling arrangements between the tug and barge in the prior art. It thus has been desirable to develop a coupling arrangement for a tug and barge combination which is suitable for use under all weather conditions, and particularly suitable in permitting freedom in trimming, rolling, pitching and heaving, while providing sufficient rigidity between the tug and barge in turning and side drifting, as well as propulsion thrust fore-and-aft.
It is a primary feature of the invention to provide a coupling arrangement for vessels, such as a tug and barge combination, wherein fore-and-aft propulsion thrust is transferred through the coupling, and steering moment is permitted, but the vessels have considerable freedom of movement with respect to one another for other linear and rotational motions, including pitch, heave, changes in draft, etc., as well as rolling motions in some cases. Another feature is the provision of a tug and barge coupling arrangement which is able to withstand the forces encountered in heavy seas, but yet does not require unduly heavy and bulky structures for the coupling mechanism. Also, a feature is the facility with which the coupling mechanism may be connected to existing vessels, or built into new vessels, without excessive alteration of the remaining structures.
In accordance with a preferred embodiment of the invention, the coupling arrangement basically comprises a vertical slot at the end of one vessel, and a protruding pin at the end of the other vessel, with the pin being shaped in some cases to allow it to rotate in the slot as well as move up and down. Also, a pair of struts connect the two vessels, those struts being preferably rigid bars coupled to both vessels by swivel or hinged joints and angularly positioned with one on each side of the slot and pin.
Novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as further features and advantages thereof, may best be understood by reference to the following detailed description of particular embodiments, when read in conjunction with the accompanying drawings, wherein:
FIG. 1 is a schematic representation in perspective of a tug and barge combination, illustrating principles related to the invention; 1
FlG. 2 is a plan view of a tug and barge coupled according to one embodiment of the invention;
EEG. 3 is an elevation view of the combination of FIG. 2;
PEG. d is a plan view of a tug and barge according to another embodiment of the invention;
FIGS. 5a-5c are schematic representations of a tug and barge combination illustrative of concepts of the invention;
l lG. s is a detail view of a swivel joint used to connect the linkage bars to the tug and barge;
. FIGS. 7, 7a and 7b are detail view of the protruding member on the bow of the tug in FIGS. 2-4 according to various embodiments of the invention;
FIG. 8 is a pictorial view of another embodiment of the invention employing a different connecting arrangement for the bars;
FIG. 9 is a plan view of a tug-and-barge coupling according to another embodiment of the invention;
FIG. ltl is an elevation view of the coupling arrangement of FIG. 9;
FIG. ill is a front elevation view in section of the coupling arrangement of FIGS. 9 and 10; and
FIGS. 12a and 1212 are plan and elevation views, respectively, of a coupling arrangement according to another embodiment.
It will be noted that like parts appearing in several views of the drawing will bear like reference numerals. The drawings are a part of this specification and are incorporated herein.
Referring now to FIG. 1, there are illustrated in schematic form a pair of vessels to be coupled together; in the context of the preferred embodiment of the invention the vessels will include a tugboat 10 which is to be coupled to a barge ll for the purpose of propelling the barge. Either of the vessels, or the two vessels coupled together, might tend to exhibit linear motion in either of the X, Y or Z axes as illustrated, or rotational motion about either of these axes. According to the invention, certain of these linear or rotational motions are to be freely permitted, and certain are to be constrained. In common nomenclature, rotational motion about the X axis is referred to as pitching, rotational motion about the Y axis is rolling, and of course rotation about the Z axis is either yawing or a steering movement. Similarly, linear motion along the X axis is side drift, along the Y axis is the desired propulsion ahead or astern, and along the Z axis is bobbing or hearing, and up-anddown movement. Also, relative movement along the Z axis represents changes in draft, as caused by changes in loading. These three linear motions and three rotational motions will completely define any movement of the vessel from an analytical standpoint.
The objective in one embodiment is to provide complete freedom to all components, with the exception of linear motion along the Y axis and rotational motion around the Z axis. That is, the tugboat 10 is to push the barge Ii ahead or astern, and is to be considered coupled tightly to the barge for steering moment. At the same time, the tugboat is to be permitted to pitch, roll or bob with little constraint. The pair will be constrained for linear motion in the X direction or for drift from side to side except for a small degree of freedom due to the inherent nature of the coupling apparatus as will be described.
Further, a certain small degree of freedom of linear movement in the directionof the Y axis will be permitted due to the structure used, as will be explained.
Turning now to FIGS. 2 and 3 of the drawings, one example of a preferred embodiment of coupling apparatus according to the invention is illustrated. The tugboat it) engages the stern of a barge ll, it being understood that several of the barges II may be secured together as a unit. The coupling arrangement includes a generally vertical slot of recess 12 formed in the stern of the barge, and to engage the slot there is provided a cylindrical member 14 fixed to the bow of the tug. In addition, a pair of struts or linkage bars 15 and 16 are provided, one being mounted on each side of the slot 12. The struts l5 and 16 are of sufficient strength to bear the forces as will be described below, and are rigid along their lengths but are coupled to the stern of the barge and to the hull of the tug by universal joints 17 which may be of the type described with reference to FIG. 6. I
The member 14 is a cylindrical pin of adequate size and strength to bear the forces encountered, this member protruding from the bow of the tug. The length of the pin is sufficient to permit some fore-and-aft movement for the purposes explained with reference to FIG. 5. The pin is cylindrical to permit freedom of rolling movements of the tug with respect to the barge. Some degree of clearance is permitted between the surface of the pin 14 and the walls of the slot .12 to allow free movement with respect to pitching, rolling, and slight foreand-aft movements. Thus, the diameter of the cylindrical member 14 is almost equal to the width of the slot 12, the difference being as small as practical. Either on the member 14 or in the slot 12 at the sidewalls, it may be appropriate to provide a shock absorbing medium such as a hard rubber bumper or the like. The bumper will affect the permitted clearance.
The combination of the cylindrical member 14 in slot 12, along with the bars 15 and 16 hingedly connected to the tug and barge by universal joints, provides the desired freedom of movement and constrains for the coupled vessels. Within the limits imposed by the mechanical linkage, there is complete freedom of rolling, pitching, and parallel sinkage or up and down heaving or bobbing movements. At the same time there is constraint against relative movement between the two vessels for yawing or steering, or for fore-and-aft movement, within limits. In operation, rolling of the tug will cause the cylindrical pin to rotate in the slot 12, while pitching or bobbing will cause the pin to move up and down and/or cant in a vertical plane, as will changes in loading or draft.
The length of the slot 12 would be sufficient to permit continuous movement of the pin relative thereto, over the entire range of possible positions taking into account loaded or unloaded conditions of the barge as well as violent movement of the barge and tug in heavy seas. Stops may be provided at the upper and lower ends of the slot to prevent the pin from being completely dislodged in the unusual event of the movement being extensive enough to drive the pin past the end of the slot. While the slot is shown recessed into the stern of the barge, clearly the slot could be formed as a channel attached to the stern of an existing vessel.
Referring to FIG. 4, it is noted that the coupling mechanism of the invention is particularly adapted for use with a barge constructed in the form of my abandoned application Ser. No. 596,652. In this embodiment the tugboat 10 is constructed as in the example of FIGS. 1 and 2, while the barge 11' defines at its stern a large vertically extending recess 18 of sufficient size to accommodate a substantial length of the bow of the tugboat. Also, of course, a vertical slot 12 is provided as before to be engaged by the cylindrical member 14. Again struts l and 16 complete the linkage, these being coupled to the stern of the barge and to the tugboat by universal joints. The advantage of the use of the deep recess so that the bow of the tug protrudes far into the stern of the barge is to reduce the forces bearing upon the pin 14 and the walls of the slot 12, as will be explained. Just as before, the depth of the slot and length of the pin are selected to permit some slight fore-and-aft motion.
Turning now to FIG. 5, the purpose for permitting a small degree of freedom of movement along the Y axis will be apparent. In FIG. 5a, a stern-on view of the tug and barge with both at an even keel show the struts l5 and 16 to be of a given length. When seen in the view of FIG. 5b where the tug is at a rolled position with respect to the barge, the struts 15 and 16 must either elongate or otherwise reconcile the difference in distance from the stem to the side of the tug between the horizontal and the tilted positions. To this end, as seen in FIG. 5c, the tug moves inwardly with respect to the barge when the tug rolls; thus the pin 14 must be permitted to move deeper into the slot 12 so that the distance from the stem to the side of the tug along the struts and 16 will remain constant. Similar principles would apply for pitching or bobbing movements. At some limit of travel, either the front end of the pin 14 will engage the forward wall of the slot, or else the bow of the tug will engage the flat portion of the stern of the barge, but within a wide range of relative movements this will not occur.
In the embodiment thus far described, the thrust of the tug against the stern of the barge to propel the barge or barges is transmitted through the linkage bars or struts 15 and 16 rather than at the bow of the tug as is the usual case. It will be seen, however, that this thrust for propulsion is about an order of magnitude smaller than the forces which the linkages must be designed to withstand due to other factors. In a typical example, this thrust for propulsion may be perhaps 150,000 pounds, compared to other factors of over 1 million pounds. The order of the forces involved may be readily approximated, using the assumption that the tug and barge combination is rigid. Empirical measurements have shown that forces in any direction will be about three-fourths of the weight of the tug as a maximum under these circumstances. Typically, the weight of the tug is about 1,000 tons, so the forces acting upon the center of gravity with the joints restrained are about 750 tons or 1.5 million pounds. Such forces are encountered when the tug-and-barge combination is tossed about among waves in heavy seas.
Other forces to be considered, of course, are the thrust from the propeller, and the steering moment. It can be shown that these are rather small, on the order of the one-tenth that of the forces caused by the seas, the thrust by the propeller being about 150,000 pounds for a 5,000 horsepower tug. The design factors, then, are directed to providing a linkage which will survive punishment by wave forces, rather than factors relating to steering or thrust from the propellers.
The function of the slot 12 and cylindrical member 14 may be appreciated by roughly approximating the forces in the struts with and without these elements. Using the assumptions above, and assuming the length from the center of gravity of the tug to the stern of the barge to be about 75 feet, with the width of the stern of the barge about feet and the angle of the struts with respect to the stem 45 degrees, it can be calculated that the forces of tension or compression in the struts l5 and 16 would be about 1.75 million pounds in the embodiment of FIGS. 2 and 3. In contrast, in a similar structure without the pin and slot, assuming the struts to be rigid horizontally, forces of almost 50 percent more may be encountered. If the struts are almost parallel to the centerline of the vessels, forces almost double that in the FIG. 2 structure would be encountered. Further, if a recess 18 as in FIG. 4 of 25-foot depth is utilized, the forces under the assumption given could be reduced to the just slightly greater than 1 million pounds in the struts 15 and 16. Of course, making the recess 18 deeper will bring the center of gravity of the tug closer to the center of gravity of the barge, or of the overall two vessel combination, and thus reduce the forces encountered even further.
The forces that occur in the struts can be further reduced by changing the angle of the bars with respect to the stern, a larger angle reducing the force. Clearly, the pin 14 may be more readily constructed to withstand forces of this nature, than can the struts 15 and 16 along with the universal joints 17.
The swivel connections or universal joints 17 may be of the type shown in FIG. 6, although it is noted that there are no specific limitations on the type of joint used, except that the design must be such that the forces encountered may be borne by the unit, and rotation about any axis is permitted. A ball joint may be used in place of the type shown in FIG. 6. For convenience, and also as a safety feature, a quick-releasing mechanism may be included in the joints 17, usually at the tug ends, so that the tug can be quickly disengaged from the barge. A hydraulic locking or decoupling mechanism may be provided for this purpose.
As seen in FIGS. 7, 7a and 7b, the pin 14 may be a cylinder attached to the bow of the tug 10, or the bow itself may be shaped to provide the function of the pin. It will be noted that the pin need not be a complete cylinder, since the tug should not roll more than about 30 in either direction. Thus, the top and bottom of the pin might be flat, or preferably a vertical member 19 may extend through the pin 14 as seen in FIG. 7a to limit the rolling movement of the tug with respect to the barge. This arrangement not only provides a mechanical stop, but also increases the strength of the pin.
Another slight degree of freedom present in the coupling arrangement as described above is that incident to swinging the stern of the tug as occurs upon dipping of one side of the tug while the other stays at the same level. Considering FIG. 5a, if the starboard side of the tug sinks while the port side remains stationary, the bar 16 remaining of fixed length, the stern of the tug will swing to the right slightly. Therefore, the pin 14 will turn a small amount within the slot 12. This movement is small and will be absorbed by the mechanical clearance between the pin and slot, or by the rubber shock absorber as may line the pin or slot.
Referring to FIG. 7b, it is seen that the bow of the tug itself, rather than an attachment or separate member added to the bow, may form the protrusion 14. In this case the wedgeshaped portions and 21 of the bow extending above and below the member M provide the same function as the key member 19 in the embodiment of FIG. 7a.
Another embodiment of the invention is shown in FIG. 8; here the bars 15 and 16 are connected together at a juncture 22, which in turn is connected to the bow of the tug It) by a universal or swivel joint 23. The forward ends of the bars 15 and M are connected to the stern of the barge 11 by hinge joints 24 and 25; these joints permit movement of the bars 15 and 16 only in the vertical direction relative to the barge. Turning, side-to-side, or pivotal movement is unnecessary. The joint 23 permits freedom for rolling motion, such movement causing the member 14 to turn in the slot 12. To this end, the axis of the fore-and-aft pivot in the joint 23 preferably should be coaxial with the axis of the cylindrical or partially cylindrical member 14, both of these being in the vertical plane of the centerline of the vessels. In pitching or rolling motions, the member 14 must be permitted to move fore-and-aft in the slot 12 as before.
Referring to FIGS. 9, 10 and 11, an embodiment of the invention is shown wherein the protruding bow member is formed by a shape portion of the bow of the tug 10. The bow of the tug fits within a recess 18, as in the FIG. 4 embodiment. A wide vertical slot 12' receives the bow member 14', which as seen in FIGS. 10 and II is a large protruding part of the bow. The member 14' has curved sides 28 which are covered by thick bumpers 29. The curved shape of the sides 28 and bumpers 29 permits the tug to roll with respect to the barge, but this rolling movement will be impeded as the more linear shape of the upper portion of the member M engages the sidewall of the slot 12'. Bumpers 30 are provided on the sides of the recess 18 to absorb impact when pronounced rolling or pitching motion occurs, or when the tug is maneuvering to the make the coupling. Another bumper 31 on the forward face of the bow member 14 cushions contact between the bow member and the forward face of the slot 12 as may occur when pitching or upon changes in draft.
Another embodiment of the invention using a rectangularshaped bow member, instead of a cylindrical or curved shape, is shown in FIG. 12a and FIG. 12b. This embodiment is quite similar to that of FIGS. 9-11, but includes a bow member 32 which is rectangular in shape. The slot 12' is the same as before, as is the recess 18 in the stem of the barge. The outside of the bow member 32 is encased in large, thick rubber bumpers 33. The thickness of these bumpers 33 may be about 1 foot, and the structure may be made up of 12 inches X 12 inches rectangular fenders. The vertical height of the bumper 32 may be about 10 feet, and the width athwart-ships somewhat less. The clearance between the bow member 32 and the slot 12 permits very slight rolling motion of'the tug relative to the barge, while the resilient nature of the bumpers accommodates considerable rolling motion. About 5 of relative roll would be possible with the coupling described.
The concept of this invention has been thus far described with reference to embodiments which permit rolling motion of the tug relative to the barge. However, this feature is not always preferable, and may in some cases be eliminated advantageously. Referring again to FIG. 12a and 1212, instead of having resilient bumpers 33 which deform several inches, the bumpers may be composed of nonyielding material such as wood, so that very little if any rolling motion is possible. In this case the bow member 32 and its bumper 33 would fit fairly close in the slot 12', with only enough clearance to allow vertical movement of the member in the slot and pitching movement. In this situation, the bow member, slots, and struts must be made more sturdy, as more forces will be applied to them in heavy seas than in the embodiments where constraints are not imposed on rolling motion. This embodiment thus constrains rotary motion about the Y axis as defined above, this being the major axis of the bow member itself and also of the tug. However, some freedom of rotation about the X axis is permitted; the X axis is perpendicular to the slot and perpendicular to the axis of the bow member. Of course, the coupling provides constraint for rotation about the Z axis.
Again referring to FIG. 12b, another feature is shown which has not been previously described. The discussion of FIGS. 12a and 12b given above assumes that the feature now to be described was not present. Vertical movement of the bow member 32 within the slot 12 may be further constrained by a strut 34 which comprises a-hydraulic piston and cylinder arrangement 35 connected by bars 36 and universal or swivel joints 37 to the tug and barge. The joint 37 at the lower end of the strut 34 is connected to the bow member 32, and the joint 37 at the upper end is connected to a horizontal beam 38 at the top of the slot 12'. The chambers on opposite sides of the piston in the hydraulic cylinder 35 are connected together through a small orifice in the piston. The orifice permits slow movement of the piston as may occur upon changes in draft of the vessels. However, the piston is not permitted to move up and down rapidly as would occur during pitching movements. The member 32 may still rotate about a horizontal axis to permit relative pitching movements, but this axis will be located at the lower end of the strut 34 rather than at the natural foreand-aft center of rotation of the tugboat. The constraint of the strut 34 does not prevent slight fore-and-aft movement of the member 32 as may occur in pitching or changes of draft. The strut 34 includes a shock absorbing function as provided by the hydraulic cylinder; impact stresses are thus relieved. An air chamber may also be included to increase the effectiveness of the shock absorbing function.
The strut 34 of FIG. 12b may be used in anyof the other embodiments of the invention, although it is understood that rolling motion would be somewhat impeded by the presence of the strut, and a much more substantial strut structure would have to be used to withstand the additional stress of rolling, compared to that necessary in the embodiment of FIG. 12a and 12b.
In the description of the invention, the struts or bars 15 and 16 are shown or referred to as being of fixed length; by this is meant that the struts do not contract or expand while in operation aboard vessels at sea. However, it is appropriate that the struts be adjustable so that they may be fitted to various tugbarge combinations, or to accommodate widely varying draft. Once the proper length is set, further changes in length would be prevented by a locking mechanism. In some cases a shock absorbing mechanism of very hard characteristics may be approprrate.
The struts may be carried by either the tug or the barge in any of the embodiments described. In one practical embodiment, the struts are carried by the barge and are spring biased in an upward position when the tug is not coupled, so that the struts will not be damaged by collision with other vessels or wharfs, and will not hang in the water. When the tug approaches from the rear for coupling, the struts may be pulled downward to engage releasable couplings on the sides of the bow section of the tug. This operation may be performed by persons on the tug, no one need board the barge.
In contrast to tug-and-barge coupling heretofore developed, the present invention employs rigid struts which are fixed to the tug and barge by joining devices which do not allow the ends of the struts to move with respect to the vessel, except in an angular or pivotal motion as by a hinge or swivel. The ends of the struts do not slide up and down, nor move in a fore-andaft direction, nor move athwart-ships.
Although described in the context of embodiments showing the tug pushing a barge, if for some reason it was necessary to have the leading vessel provide the propulsion thrust, the same principles could apply. Also, even though it is clearly preferable for a tug-barge coupling to have the slot in the stern of the tug, other vessels may be such that the pin and slot would be reversed.
While the invention has been described with reference to particular embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as further embodiments of the invention may be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.
1. Apparatus for coupling first and second vehicles while permitting certain freedom of movement of one vehicle relative to the other comprising:
an elongated slot defined at one end of the first vehicle, the
slot generally facing the second vehicle;
a member protruding from one end of the second vehicle to extend into said elongated slot, adapted for freedom of movement along the slot;
elongated means connecting the first and second vehicles to one another on both sides of said slot, the elongated means being connected at both ends to the first and second vehicles by swivel or hinge-type joining means; and
said joining means permitting angular pivotal movement of the elongated means with respect to the vehicles, and preventing the ends of the elongated means from moving in a direction parallel to the elongated slot with respect to the vehicle to which each end is connected.
2. Apparatus according to claim 1 wherein the elongated means are generally fixed in length.
3. Apparatus according to claim 1 wherein the elongated means include a pair of struts, one on each side of the slot, the struts being connected to at least one of the vehicles by swiveltype means.
4. Apparatus according to claim 1 wherein the member is shaped to permit rotational motion in the slot.
5. Apparatus according to claim 1 wherein the member is shaped to impede rotational motion in the slot.
6. Apparatus according to claim 1 wherein the member has curved transverse sides with the major axis of the member being generally parallel to a path of movement of the first and second vehicles.
7. Apparatus according to claim 1 wherein the elongated slot and the member are of such sizes and lengths to permit a slight movement of the vehicles with respect to one another along an axis generally parallel to a major path of movement of the vehicles, while the coupling apparatus permits propulsion thrust of one vehicle relative to another.
8. Apparatus according to claim 1 wherein the slot is generally vertical and located along or parallel to a centerline of the first vehicle.
9. Apparatus according to claim 8 wherein the member is at the forward end of the second vehicle and the slot is at the stem end of the first vehicle, the vehicles being floating vessels.
10. Apparatus according to claim 9 wherein the elongated means are a pair of struts, each extending from a fixed point on the second vessel to a fixed point generally at the stern of the first vessel.
11. Apparatus according to claim 10 wherein the struts are fixed in length and are connected to the first and second vessels by swivel-type or universal-type joints.
12. Apparatus according to claim 1 wherein a large recess is provided in said one end of said first vehicle to receive a major portion of the end of the second vehicle.
13. Apparatus according to claim 12 wherein the first vehicle is a barge or like floating vessel, and the second vehicle is a tugboat or the like; the large recess being in the stern of the barge and the protruding member being at the bow of the tugboat; the elongated means, being a pair of struts of generally fixed length, are on each side of the slot, the ends of the struts being connected to the barge and tugboat by swivel-type joinmg means.
14. Apparatus according to claim 13 wherein the member protruding from the bow of the tug has substantially straight sides whereby rolling motion between tugboat and barge is impeded.
15. Apparatus according to claim 13 wherein the member protruding from the bow of the tug has curved sides whereby there is substantial freedom for rolling motion between tug- .boat and barge.
16. Apparatus according to claim 1 wherein the vehicles are floating vessels, and freedom of movement of the second vehicle relative to the first vehicle is provided for movements of pitch, heave, and changes of draft, whereas constraint on freedom of movement is provided for yawing and fore-and-aft movements.
17. Apparatus according to claim 16 wherein the constraint upon fore-and-aft movements includes a certain degree of freedom of movement incident to pitching movements.
18. Apparatus according to claim 3 wherein the struts are connected together at one end and are both connected to the second vehicle by a single swivel-type joint which is located generally along the centerline of the second vehicle.
19. Apparatus according to claim 18 wherein the other ends of the struts are connected separately to the first vehicle by hinge-type joints.
20. In apparatus for coupling the bow of a tugboat or the like to the stern of a barge or other vessel, for the purpose of propelling the barge while permitting certain freedom of movement of the vessels relative to one another;
an elongated vertical slot provided at the stern of the barge generally along or parallel to the centerline thereof, the slot having opposing vertical walls;
a member protruding from the bow of the tugboat and extending generally in a forward direction into said vertical slot, the member having lateral faces for engagement with the walls of the slot, whereby the member in the slot functions to permit freedom of pitching movement of the tugboat relative to the barge while impeding athwart-ships movement; and
a pair of elongated generally rigid bars extending from the tug to the stern of the barge, one being located on each side of the slot, the bars being laterally spaced from the slot, the bars bearing thrust from the tug to the barge.
21. In a coupling arrangement according to claim 20, the bars being connected to the tug and the barge by swivel-type or hinge-type joints.
22. In a coupling arrangement according to claim 21, the slot and the member being of such size and length as to permit slight fore-and-aft movement incident to pitching and changes of shift.
23. In a coupling arrangement according to claim 20, the sides of the member protruding from the bow being substantially flat and parallel to the walls of the slot, to impede rolling movement of the tug relative to the barge.
24. In a coupling arrangement according to claim 20, the sides of the member protruding from the bow being of curved shape to allow some freedom of rolling movement of the tug relative to the barge.
25. In a coupling arrangement according to claim 20, wherein a large recess is provided at the stern of the barge to receive a major portion of the bow of the tug, the vertical slot being at the apex of such recess.
26. In a coupling arrangement according to claim 20, wherein the member has generally curved sides but is shaped near top and bottom to provide a mechanical stop to inhibit rolling movement of the tug beyond a selected amount.
27. In a coupling arrangement according to claim 20, the rear ends of the bars being connected together and to a universal-type joint which is located generally along or parallel to the centerline of the tug. I 1
28. In a coupling arrangement according to claim 27, the front ends of the bars being connected separately to the stem of the barge 'by hinge-type joints which permit relative movement only in a vertical direction.
29. In apparatus for-coupling the bow of atugboat or the like to the stern of a barge or other vessel, for the purpose of propelling. the barge while permitting certain freedom of movement of the vessels relative to one another;
an elongated vertical slot provided at the stern of the barge at about the midpoint thereof, the slot having opposing substantially vertical walls; i
a member protruding from the bow of the tugboat and extending generally in a forward direction into said vertical slot, the member having lateral faces engaging the walls of the slot, whereby the member may move up-and-down in the slot or rotate at least partially about a horizontal axis, but is prevented from rotating in the slot about a vertical axis, the member and slot being of shape and size to substantially prevent yawing of the tug relative to the barge but to permit pitching, heaving and changes of draft of the tug relative to the barge; and
a pair of elongated bars extending from the tug to the stern of the barge, one being located on each side of the slot.
30. In a coupling arrangement according to claim 29, wherein the slot and the member are of such size and length to permit slight fore-and-aft movement incident to pitching.
31. In a coupling arrangement according to claim 29,
wherein a large recessis provided at the stern of the barge to receive a major portion of the bow of the tug, the vertical slot movement.
33. In apparatus according to claim 29, the lateral faces of the member being curved to permit rolling movement.
34. Apparatus for coupling first and secondvehicles while permitting certain freedom of movement of one vehicle relative to the other comprising:
an elongated slot defined at one end of the first vehicle, the slot generally facing the second vehicle, the slot having opposing walls;
a member protruding from one end of the second vehicle to extend into said elongated slot, adapted for freedom of movement along the major axis of the slot and adapted for at least partial freedom of rotational movement about an axis perpendicular to the major axis of the member and the slot, the member and slot being of shape and size to substantially prevent movement in the direction transverse to the major axes of the member and slot or rotation of the member about an axis parallel to the major axis of the slot; and
elongated rigid means of fixed length connecting the first and second vehicles to one another on both sides of said slot, the elongated means being connected at both ends to the first and second vehicles by swivel or hinge-type joints.
35. Apparatus according to claim 34 wherein a large recess is provided in said one end of said first vehicle to receive a major portion of the end of the second vehicle, the recess being at the apex of such recess, the recess being substantially being large enough to permit clearance for rolling and pitching movements of said end of the second vehicle with the recess.
36. Apparatus according to claim 34 wherein means are provided for impeding short-duration vertical movement of the member within the slot as may be caused by pitching or the like while permitting long-duration vertical movement as may be caused by relative changes in draft.