Marine Towing Device

Abstract

A marine towing device has support means which is to be mounted on a marine vessel. A hook is pivotably mounted in a frame and interposed between and connected with both the support means, and the hook is an elastically yieldable unit which yields elastically to a predetermined maximum extent if tensile forces develop between the support means and the hook, as when the latter is engaged with an element to be towed.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to a marine towing device, and more particularly to a marine towing device utilizing a so-called slip hook.

It is known to mount such towing devices on marine vessels in such a manner that the frame of the hook--in which the hook itself is pivotably journalled--is directly and articulately connected with the marine vessel. For this purpose the portions of the vessel, usually a portion of the superstructure thereof, are specially reinforced to be able to withstand the stresses which develop when the hook is engaged with an element to be towed. Usually a cable or rope is interposed between the element and the hook, being connected to the element to be towed and being engaged by the hook. The problem with these prior art constructions resides in the fact that momentary tensile stresses--such as for instance develop if the rope engaged with the hook suddenly changes from a slack to a taut condition--are directly transmitted to the towing vessel. This frequently leads to breakage of the cable rope, and may have even more severe consequences, namely disturbances in the operation of the marine vessel or even a significant damage to the vessel itself, for instance the superstructure on which the towing device is mounted.

It is known to attempt to correct this by interposing in the towing rope--or constituting the latter of--sections of natural fiber, for instance Manila hemp. This material is capable of yielding to a certain extent and thus to provide a relief for the problem in question. However, ropes made of such material must have rather large cross-sections in order to withstand the high stresses placed upon them, stresses which in case of momentary development of the stress cannot in practice be controlled. In actual use it is frequently found that Manila hemp rope of the necessary strength--that is cross-section--is frequently not available when needed, particularly when the towing rope is changed over from one towing vessel to another so that there may not have been any previous possibility of making preparations.

In any case, no means has heretofore become known in this art which is capable of avoiding the aforementioned problem and which in all operational circumstances will guarantee a significant reduction in the stresses transmitted to the marine vessel to which the towing device is secured.

SUMMARY OF THE INVENTION

It is, accordingly, an object of the present invention to overcome the aforementioned disadvantages.

More particularly it is an object of the present invention to provide a marine towing device which is not possessed of these disadvantages.

A further object of the invention is to provide such a marine towing device which avoids the sudden transmission of tensile stresses to the marine vessel on which the device is carried, but which does not adversely affect the towing stresses which can be placed upon the device.

In pursuance of the above objects and others which will become apparent hereafter, one feature of the invention resides, in a marine towing device, in the combination which briefly stated comprises support means adapted for mounting on a marine vessel, engaging means adapted for engagement with an element to be towed, and intermediate means interposed between and cooperating with the support means and the engaging means. According to the invention the intermediate means is elastically yieldable to a predetermine maximum extent in response to development of a selected tensile stress between the support means and engaging means.

The construction of the intermediate means in accordance with the present invention is such that it is capable of transmitting towing stresses up to a selected value without reacting, but will react to towing stresses in excess of this value, particularly to sudden tensile stresses which develop.

In accordance with one embodiment of the invention the intermediate means comprises a rod pivotably connected with the frame of the engaging means or hook unit, and a sleeve surrounding the rod and in which the latter is axially slidably guided, with resilient means--such as a spring or the like--being axially compressible in response to movement between the rod and the tubular member or sleeve in a sense withdrawing the two from one another. It has been found that the elastically yieldable means may particularly advantageously be in form of a sleeve of synthetic plastic material which is elastically deformable in axial direction and surrounds the rod, engaging with its opposite axial ends the tubular member and the rod, respectively. Suitable synthetic plastics for this purpose are already well known and commercially available under various names such as Adacell, Vulkollan or the like foamed polyurethan.

With this construction it is readily possible to determine the extent to which the rod and sleeve can move axially with reference to one another in a sense moving away from each other, that is the extent to which the unit can elastically yield, by making the outer diameter of the sleeve smaller than the inner diameter of the tubular member to such an extent that the outer circumferential surface of the sleeve will engage the inner circumferential surface of the tubular member--whereupon the elastic deformation ceases--when the desired elastic deformation has been reached. It will be appreciated that in response to axial deformation of the sleeve the same will be radially outwardly deformed so that the contact between the outer surface and the inner surface of the tubular member takes place.

Advantageously the support means by way of which the towing device is connected with a marine vessel comprises a universal joint to afford free movement of the device with reference to the vessel.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a somewhat diagrammatic fragmentary axial section through a device according to the present invention;

FIG. 2 is a section taken in a plane extending at right angles to the plane of the section in FIG. 1; and

FIG. 3 is a view similar to FIG. 1, but on an enlarged scale and in a more fragmentary illustration, of a further embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Discussing firstly the embodiment illustrated in FIGS. 1 and 2 it will be seen that reference numeral 1 identifies a hook, which in conventional manner, is pivotably mounted in a frame 2 for turning movement about a substantially horizontal axis. In its operating position the hook 1 is maintained by means of a non-illustrated slip device which, when it is desired to slip or release the rope or cable engaged by the hook 1, can be actuated or "slipped" by the lever 3. The elements 1, 2 and 3 are entirely conventional and well known to those skilled in the art; for this reason they have been illustrated in FIG. 1 and particularly in FIG. 2 in broken lines. The illustration is to be understood as being merely an aid to a better understanding of the position of the novel intermediate means with reference to the elements 1, 2 and 3 which together constitute the engaging means of the towing device.

In accordance with the present invention I provide an intermediate means E which is located between and connected with the frame 2 and the support means 4 which in turn is secured to a portion of a marine vessel 5. The portion of the vessel 5 may be a part of the superstructure thereof; its particular identity is immaterial for purposes of the invention.

The element E comprises, as illustrated, a rod 6 which is articulately connected with the frame 2, as shown at 6a, and a tubular member 7 which surrounds a portion of the rod 6 with the latter extending through an opening in the end wall 9 which closes the end of the tubular member 7. Surrounding the rod 6 within the confines of the tubular member 7 is a sleeve 8 of synthetic plastic material which is axially resiliently compressible and which is confined between and bears upon the end wall 9 of the tubular member 7 and a shoulder 10 provided at the free end of the rod 6 adjacent the nut 6b. The presence of the sleeve 8, which latter constitutes elastically yieldable means for the element E, also serves to provide guidance for the rod 6 during axial movement between the same and the sleeve 7. Reference numeral 11 identifies a universal joint which is a part of the support means 4 and which affords the element E freedom of movement with reference to the vessel 5.

Coming now to the embodiment illustrated in FIG. 3 it will be seen that this differs from that of FIGS. 1 and 2. In particular, the embodiment of FIG. 3 utilizes for the intermediate element a tubular member 7a which has one closed end and one open end, with the latter facing towards the vessel on which the device is mounted, and which vessel must be thought of as being located at the right of the device in FIG. 3. Reference numeral 11 identifies a connecting member which is secured to the vessel and anchored--as by means of a bolt 14 traversing openings adjacent the free end of the tubular member 7a and the member 11--with the tubular member 7a. Accommodated within the tubular member 7a is resilient means in form of an elastically compressible body or member 15 of suitable synthetic plastic material. The rod member 6 of FIGS. 1 and 2 has here been replaced with the member 6a which may also be thought of as a rod member but which has a bifurcated end portion surrounding the tubular member 7a from the closed end thereof and being axially slidable with reference to the tubular member 7a. The latter is provided inwardly of its open end with a pair of diametrally opposite slots 13 which are elongated in the axial direction of the tubular member 7a, and a pin, bolt or analogous member 12 extends through these slots 13 and is anchored in the bifurcated end portion of the member 6a. Movement of the member 6a axially of the member 7a in the direction towards the left-hand side of the FIG. 3, movement of the member 7a towards the right-hand side of FIG. 3, or simultaneous movement of the member 6a and 7a in their respective directions, causes the pin or analogous member 12 to bear against the member 15 and thereby compress the same axially, obtaining the desired resilient spring action. In the illustrated embodiment of FIG. 3, however, I have provided a small disc or plate 16 which is suitably secured to the pin 12--as by welding--within the confines of the tubular member 7a, and which is the element actually contacting and effecting axial compression of the member 15. This provides for more even compressing action.

The length of the slots 13 defines the limits of compression and sudden shock-like stresses are absorbed by the member 15 when they exceed a certain limit. Of course, if the pin 12 moves into abutment with the left-hand ends (with reference to FIG. 3) of the slots 13, then there is a direct transmission of stresses from the frame 2 to the member 11 and thereby to the vessel, and this will ordinarily take place only if the stresses build up gradually rather than momentarily and suddenly.

It will be appreciated that the device according to the present invention affords greater safety and ease of operation, eliminates economic losses and dangers due to breakage of the rope or cable used for towing, and eliminates economic losses and dangers to personnel resulting from the sudden transmission of stresses in shock-like manner to the vehicle--that is marine vessel--on which the device is mounted.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a marine towing device, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

Claims

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended

1. A marine towing device, comprising support means adapted for mounting on a marine vessel; engaging means, including a slip hook arrangement adapted for engagement with and release of an element to be towed, at the will of an operator; and an intermediate device between and cooperating with said support means and engaging means, including an elongated tubular housing connected with one of said means, and a one-piece elongated elastomeric element accommodated axially and with slight radial play in said housing and operatively connected with the other of said means whereby, in response to development of a selected tensile stress between said engaging and supporting means and acting longitudinally of said housing, said elastomeric element will undergo axial compression and concomitant radial expansion into progressively increasing frictional engagement with an internal surface of said housing, so as to provide a progressive energy-absorption effect.

2. A towing device as defined in claim 1, said support means comprising a frame and a hook pivotably mounted in said frame; and wherein said intermediate device is connected with said frame.

3. A towing device as defined in claim 1, said elastomeric element being an elastically axially compressible sleeve of synthetic plastic material surrounding said rod portion within the confines of said tubular housing.

4. A towing device as defined in claim 3, said sleeve having an exterior surface and an outer diameter and undergoing radially outward expansion in response to axial compression; and wherein said tubular housing has an interior surface adapter to be engaged by said exterior surface and an inner diameter which exceeds that outer diameter by an amount determined in dependence upon the maximum desired axial compression of said sleeve.

5. A towing device as defined in claim 1, said support means including a universal joint for affording said intermediate device freedom of movement with reference to a marine vessel on which said support means is mounted.

6. A towing device as defined in claim 1, said intermediate device further comprising a rod-portion partly accommodated in said housing and being connected with said other means, said elastomeric element cooperating with said rod portion and housing and being compressible in response to relative sliding movement thereof in axially opposite directions.

7. A marine towing device, comprising: support means adapted for mounting on a marine vessel; engaging means, including a slip hook adapted for engagement with an element to be towed; and an intermediate device between and cooperating with said support means and engaging means, including an elongated tubular housing connected with one of said means and having a closed end and an open end which faces and is connected with said support means, an elongated elastomeric element accommodated coaxially and with slight radial play in said housing and operatively connected with the other of said means whereby, in response to development of a selected tensile stress between said means and acting longitudinally of said housing, said elastomeric element will undergo axial compression and concomitant radial expansion into engagement with an inner circumferential surface of said housing, a rod-shaped portion having a bifurcated end which embraces said housing and extends from said closed end toward said open end, said elastomeric element being resiliently compressible and accommodated in said housing, and a contact portion with said bifurcated end and adapted to bear upon and compress said elastomeric element in response to relative movement of said rod-shaped portion axially of said housing and away from said open end.

8. A towing device as defined in claim 7, said housing being provided with a pair of axially extending diametrally opposite slots, and said contact portion comprising a pin extending through said slots and having opposite terminal sections connected with said bifurcated end.

9. A towing device as defined in claim 8, said contact portion further comprising a plate member secured to said pin within the confines of said tubular housing and oriented in a plane transverse to the axis of said housing.

10. A towing device as defined in claim 7, said elastomeric element being a resiliently compressible member of synthetic plastic material.