KEEL FOR BOATS

Abstract: Improved keels which may reduce the draft of boats in certain positions. According to the disclosure, a keel comprises two keel halves (2a, 2b) which, by means of a power unit (6) and a power transmission system, are pivotal about a horizontal, longitudinally directed shaft (4a, 4b) or each about a shaft placed side-by-side and disposed in the upper region of the keel halves. The keel halves (2a, 2b) may be pivoted between one position in which their one side abuts against each other's and one position in which the keel halves are separated. The keel may be readily adapted to the majority of hulls without the need of making major modifications to the hull. This is achieved in that the keel is provided at its top with a frame (5) which has a substantially planar upper side apart from the keel bolts (10) which project upwardly from these upper sides. Furthermore, the power unit (6) is placed beneath this upper side and within the keel.

Description: KEEL FOR BOATS TECHNICAL FIELD The present invention relates to a keel for boats, the keel comprising two keel halves which, by means of a power unit and a power transmission system, are pivotal about a horizontal, longitudinally directed shaft or each about its respective shaft, disposed in side-by-side relationship and disposed in the upper region of the keel halves. The keel halves may be pivoted between one position in which their one side abuts against each others' and a position where the keel halves are separated. BACKGROUND ART It is a general wish in this art to realize the smallest possible draft, primarily in sailing vessels, so as to enable the vessel to approach beaches or to negotiate sandbanks. Similarly, sailing vessels suffer from serious problems in countries whose coastlines are markedly affected by powerful ebb and flow tides, for example when the vessel is to make its arrival or departure on the ebb tide, or even rest on the bottom with its keel during ebb tide. As a result of the keel, the boat will suffer from an extreme list. The winter storage of deep-draft keeled vessels also entails problems in supporting the boat. Certain types of sailing craft are actually incapable of resting on their keel, but must rest exclusively on their hull. Keels consisting of two pivotable keel halves have previously been proposed in this art in German Offenlegungsschrift No. 2 454 377, U.S. patent specification No. 4,044,703 and French patent specifications Nos. 1,491,403 and 2,501,147. However, the disclosures of these publications have not displayed any accepted solut i on as to how a separably pivotal keel is to be constructed SUBSTITUTE SHESt which may readily be adapted to the majority of hulls without the need of making any appreciable modification to the hull proper. The above-mentioned German publication is wholly silent as to how the keel is fixed to the hull, and neither does the publication disclose any power unit. For the keel according to the U.S. patent specification, a large hole must be made in the hull if the keel is to be mounted once construction and assembly of the hull are completed. Moreover, this specification discloses a cable system for moving apart the keel halves. In both of the above-mentioned French patent specifications, large holes must be made in the hull for accommodating such devices as the hydraul c cylinders which protrude up on the upper side of the keel. OBJECTS OF THE PRESENT INVENTION One object of the present invention is to devise an acceptable solution as to how the keel may readily be adapted to the majority of hulls without the necessity of making any large- scale modif cations to the hull proper. It should be possible to elect to provide a certain boat model with either a conventional keel or a pivotal keel according to the present invention, and also to replace or remount a previously mounted keel. Hence, the present invention makes for greater variety of selection as regards boat models, it not being necessary to limit such choice to certain particular boat models which, by sweeping modifications to the hull, have been originally adapted to accommodate pivotal keels. Other objects of the present invention are to realize a solution in respect of the construction of the power transmission system such that it will be possible to place the power unit within the keel and beneath the upper side of the keel frame. It is a further object of the present invention to attain as flat an underface as possible when the keel halves are located in their outwardly pivoted, horizontal position. This will hereby ensure a large force absorption surface when the boat is on land or resting on the seabed with its keel halves in the outwardly pivoted position. Yet a further object of the present invention is to achieve a reliable locking of the keel halves in the downwardly pivoted, mutually abutting position. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The nature of the present invention and its aspects will be more readily understood from the following brief description of the accompanying Drawings, and discussion relating thereto. In the accompanying Drawings: Fig. 1 shows a boat provided with a keel according to the present invention seen in front elevation, a number of the outwardly pivoted positions which the keel halves may assume being shown by broken lines; Fig. 2 is a schematic side elevation of the keel with its power transmission system; Fig. 3 is a longitudinal section through the power transmission system and the keel strut of the one keel half; Fig. 4 is a section taken along the line A-A in Fig. 3; Fig. 5 is a view corresponding to that of Fig. 4, but with the keel halves in an outwardly pivoted position; Fig. 6 is a vertical section through the locking device which fixedly locks the keel halves to each other in their downwardly pivoted position; Fig. 7 is a section taken along the line B-B in Fig. 6; Fig. 8 is a section corresponding to that of Fig. 3, but in this figure the power transmission system has been provided with a guide mechanism; Fig. 9 is a section taken along the line C-C in Fig. 8; Fig. 10 is a schematic side elevation of the keel with an alternative embodiment of the power transmission system; Fig. 11 is a longitudinal section through the alternative power transmission system, the frame and the keel strut of one of the keel halves; Fig. 12 is a section taken along the line D-D in Fig. 11; and Fig. 13 is a corresponding view to that of Fig. 12, but with the keel halves in an outwardly pivoted position. DESCRIPTION OF PREFERRED EMBODIMENT Referring to the drawings, Fig. 1 is a schematic view abaft a boat. The boat is provided with a keel which consists of two keel halves 2a, 2b. By solid lines, the keel halves are shown in their " downwardly pivoted, mutually abutting position, while broken lines show a number of examples of outwardly pivoted, separated positions which the keel halves may assume. Each keel half 2a, 2b is anchored in a plurality of keel struts 3a-f in Fig. 2, which, in their turn, are pivotally jointed at their upper ends to one of two shafts 4a and 4b. In their turn, the shafts are anchored to a frame which, by means of keel bolts 10, is fixedly anchored to the hull 1 of the boat. Moreover, a hydraulic cylinder 6 is bolted to the frame 5, the cylinder displacing, by means of its piston rod 7, a crosspiece 8 in the upward or downward direction. The keel struts 3c and 3d are actuated by lifting rods 9a and 9b such that the keel halves 2a and 2b are caused to pivot away from or towards one another. This phenomenon will be described in greater detail with particular reference to Figs " . 3-5. Fig. 2 shows only the one keel half 2a with its keel struts 3a-f and lifting rods 9a, 9b. It should further be noted that, in the figures, the space between the upper side of the keel halves and the horizontal section of the frame 5 has been exposed to make for clarity of perception. Naturally, this space may be covered by further masking plates and/or be partly filled with some material, for example lead or iron. However, such filling or masking must be effected such that the pivotal movement of the keel halves is not prevented or obstructed. The power transmission system is shown in greater detail in Figs. 3-5. The hydraulic cylinder 6 is fixedly anchored to the frame 5 by bolts II. The hydraulic cylinder is provided, in a per sε known manner, with a piston 12 and a piston rod 7. Pressure medium to the cylinders 6 is led via hoses 13a, 13b through holes in the keel bolts 10 to the one or other chamber of the cylinder. Regulation of the pressure medium to the chambers of the cylinders 6 may be effected in a per se known manner by means of valves, and pressurizing of the medium may be effected, for example, by means of an electrically-driven hydraulic pump or a hand pump. In its turn, the piston rod 7 is threaded into the cross- piece 8, in which two lifting rods 9a, 9b associated with the one keel half 2a are pivotally anchored each to their shaft 14a, 14b. Correspondingly, a further two lifting rods 9c associated with the keel half 2b are pivotally anchored to their cross-piece (only one of these lifting rods 9c is visible in Figs. 3-5). The other end of the lifting rods is pivotally anchored each to its stub shaft 15a-c, which are each disposed on their respective keel struts 3c, 3d, 3h, 3i. The keel struts 3c, 3h may pivot about the shaft 4a and the keel struts 3d, 3i may correspondingly pivot about the shaft 4b. For the purposes of pivoting apart the keel halves 2a, 2b, the hose 13a is placed under pressure, pressure medium being supplied to the lower chamber of the cylinder 6. In this instance, the piston rod 7 will move upwardly in Fig. 3, which also entails that the lifting rods 9a-c displace the stub shafts 15a-c upwardly and thereby pivot apart the keel halves 2a, 2b. It should here be noted that the stub shafts 15a-c (see Figs. 4, 5) are offset a certain distance in the lateral direction in relation to the vertical line through the centre of the shaft 4b. This distance creates the fulcrum which the lifting rods 9a-c employ when they pivot apart the keel halves 2a, 2b. When the keel halves 2a, 2b are located in their horizontal, outwardly pivoted position, the underface of the cross-piece 8 will lie approximately in the same plane as the underfaces of the keel halves 2a, 2b. This position of the keel halves is suitable for use when the boat is 1aid-up on land, for example for winter storage, when the boat is set on the bottom during ebb tide, or when the vessel is traversing shallow water. Naturally, use may also be made of all of the positions between this outwardly pivoted, horizontal position of the keel halves 2a, 2b and their downwardly pivoted, mutually abutting position. Figs. 6 and 7 illustrate a locking device for fixedly locking the keel halves 2a, 2b to one another. The locking device consists of a locking hook 16 which is placed in a recess 17 on the inside of the one keel half 2a. In register with this recess 17, there is provided a recess 18 on the inside of the second keel half 2b. This recess 18 is provided with a locking eye 19 in which the locking hook 16 may fixedly catch or be disengaged from by rotation about a vertical axis. This rotation is effected by means of a lower torsion bar 20 in whose lower end the locking hook 16 is fixedly mounted and whose upper end is provided with a recess 21 of non-circular cross-section. This torsion bar 20 is placed in an aperture 22 which runs from the upper side 20 of the keel half 2a turned to face the frame 5 and to the recess 17 for the locking hook 16. The upper end of the torsion bar 20 is approximately flush with the upper side 23 of the keel half 2a. There is further provided, according to the invention, an upper torsion bar 24 which runs through an aperture 25 in the centre of a keel bolt 10 and to the lower region of the frame 5. The lower end 26 of the torsion bar 24 is of conical configuration with a cross-sectional area which corresponds to the cross- sectional area of the recess 21 of the lower torsion bar. The lower end 26 of the upper torsion bar is disposed in register with, and slightly above the recess 21 of the lower torsion bar. The upper region of the upper torsion bar is bent at a right angle, such that a handle 27 is formed, a helical spring 28 being further provided about the upper region and being placed under tension between the keel bolt 10 and a fixed washer 29 on the torsion bar 24. Hereby, the lower end 26 of the upper torsion bar i11 be out of engagement with the recess 21 of the lower torsion bar when the upper torsion bar is not subjected to axial, vertically directed force. If, on the other hand, it is the intention to be able to turn the locking hook 16 into or out of engagement with the locking eye 19, an axial, vertically directed force is impressed upon the upper torsion bar 24, at the same time as the handle 27 is rotated in one or the other direction. On the application of this axial force on the upper torsion bar 24, the lower end 26 of this torsion bar will enter into engagement with the recess 21 of the lower torsion bar, such that the lower torsion bar 20 is turned simultaneously with the upper torsion bar 24. Figs. 8 and 9 illustrate a guide, whose purpose is to reduce the torque and flexural moments of force which may act upon the power transmission system exteriorally. The guide consists of an extension of both of the inner journal mounts of the cross-piece 8 for the stub shafts 14a, 14b, this extension forming a vertical flat portion 29. A vane 30 is disposed on each of the upper vertical edges of the portion 29. Each vane consists of two projecting portions 30a and 30b. The two opposing portions 30a form, together with the one longitudinal side of the portion 30, a guide in which one of the vertical sections 5a of the frame 5 forms a guide surface. The vane portions 30b abut against the outer casing surface of the hydraulic cylinder 6, whereby also this vane portion 30b will serve as a guide. As a result, undesirable exterior forces which may act on the power transmission system via the keel may be reduced. Such undesirable forces occur, for instance, when the keel halves are pivoted between their various positions, by the heave of the sea or by the speed of the boat through the water. The alternative power transmission system will now be described in greater detail with particular reference to Figs. 10-13. The keel half 2a is anchored in a plurality of keel struts 3a-f (Fig. 10). Correspondingly, the keel half 2b (obscured in Fig. 10) is anchored in the keel struts 3g-l . At their upper end, the keel struts 3a-1 are pivotally joined to shafts 31a-c. The shaft 31a. is a common shaft for the keel struts 3a, 3b, 3g and 3h. Correspondingly, the keel struts 3c, 3d, 3i, 3j are pivotally connected to the shaft 31b and the keel struts 3e, 3f, 3k, 31 to the shaft 31c. Moreover, the shafts 31b and 31c are coupled to a cross-piece 32 which, in its turn, is vertically reciprocated by means of a power unit 6, for example a hydraulic cylinder. A further shaft 33a. runs between the keel struts 3a and 3b. A TiTUTE ijrt * _; lifting rod 34a is journalled at its one end to this shaft. The other end of the lifting rod 3^a is journalled to a frame by the intermediary of the shaft 35a. Correspondingly, the keel struts 3c and 3d are provided with shafts 33b, 35b and lifting rod 34b; and the keel struts 3e and 3f with shafts 33c, 35c and lifting rod 34c. Using the hydraulic cylinder 6, the cross-piece 32 is, thus, displaced upwardly or downwardly, whereby the shafts 33a-c wilT also be entrained in this movement. If the shafts are downwardly displaced, the lifting rods 34a-c will act upon the keel struts 3a-f, such that the keel half 2a is pivoted outwardly. The opposing keel side is approximately a mirror image of Fig. 10, for which reason the same train of events will effect the keel half 2b. However, this will be described in greater detail with particular reference to Figs. 11-13. It should further be observed that the frame 5 is fixedly retained on the boat hull by means of bolts 10. Figs. 11-13 illustrate the alternative power transmission system in greater detail. The piston rod 7 is threaded into the cross-piece 32, to which the one end of the shafts 31b, 31c are coupled. The shafts 31b, 31c constitute pivotal centres for the keel halves 2a and 2b in that the keel struts are pivotally connected to these shafts. In Fig. 11, only the lifting rods 34e and 34f associated with the keel half 2b are shown. The one end of these lifting rods 34e and 34f is pivotally connected in the shaft 35e and 35f, respectively, which, in their turn, are anchored in the frame 5. The other end of the lifting rods 34e and 34f are pivotally connected to the shaft 33e and 33f, respectively. In its turn, the one end of the shaft 33e is anchored in the keel strut 3i, and the other end in the keel strut 3J. Correspondingly, the ends of the shaft 33f are anchored in the keel struts 3k and 31. According to the invention, the same can also be said for the keel struts 3c-3f of the keel half 2a and the shafts 33b, 33c, 35b and 35c. As regards the shafts 31a, 33a, 35a, the lifting rod 34a, the keel struts 3a, 3b, 3g, 3h, and corresponding parts associated with the keel half 2b (see Fig. 10), these function in a manner 3USST17U7Ϊ «yr^ i- i corresponding to that described above, but with the difference that the shaft 31a is not coupled to a cross-piece, but simply serves the purpose of constituting a common pivoting centre for the keel struts 3a, 3b, 3g and 3h. If it is now the intention to pivot apart the keel halves 2a and 2b, the hose 13b is placed under pressure, pressure medium being supplied to the upward chamber of the cylinder 6. In this instance, the piston rod will move downwardly in Figs. 11 and 12, which entails that the shafts 31b and 31c will move downwardly, like the upper parts of the keel struts 3c-3f and 3i-31. Since these keel struts are also pivotally journalled in the lifting rods 34b, 34c, 34e and 34f, these lifting rods will pivot the lower regions of the keel struts outwardly and assume the position illustrated in Fig. 13. Naturally, many alternative embodiments of the apparatus according to the present invention are conceivable without departing from the spirit and scope of the appended Claims. Thus, the keel halves 2a, 2b may, by the intermediary of the keel struts 3a-3c, each be suspended in their respective shaft, instead of the shafts 4a, 4b, 31a-31c which lie along a common, imaginary axis. In such an event, these shafts would be placed side-by-side in the same horizontal plane and at the same spaced-apart relationship from the vertical, longitudinal centre plane of the boat. Furthermore, the hydraulic cylinder 6 could conceivably be substituted by an electrically-driven motor or a cylinder using air as the pressure medium. Similarly, it is not necessary to design the upper torsion bar 25 as being spring-biased, it being also conceivable to design this torsion bar as releasably removable. " SUBSTITUTE SUL^

Claims: WHAT WE CLAIM AND DESIRE TO SECURE BY LETTERS PATENT IS: 1. A keel for boats, said keel comprising two keel halves (2a, 2b) which, by means of a power unit " (6) and a power transmission system, are pivotal about a horizontal, longitudinally directed shaft (4a, 4b, 31a-31c) or shafts disposed side-by-side and placed in the upper region of said keel halves, between one position in which the one side of said keel halves (2a, 2b) abut against each other and one position in which said keel halves are separated, characterized in that said keel is provided at its top with a frame (5) which has a substantially pTanar upper face, apart from the keel bolts (10) which project upwardly from said upper side; and that said power unit (6) is disposed beneath said upper side and within said keel. 2. The keel as claimed in Claim 1, characterized in that said power unit (6) consists of a hydraulic cylinder; and that certain of said keel bolts (10) are provided with through-holes which serve as passages for, for instance, hydraulic hoses (13a, 13b) to said hydraulic cylinder (6). 3. The keel as claimed in Claim 1, characterized in that said power unit (6) vertically displaces a rod (7) in whose lower region a horizontal cross-piece (8) is fixedly disposed, and at least one upwardly-directed lifting rod (9a, 9b) for each keel half (2a, 2b), said lifting rod being, at its lower end, pivotally journalled to said cross-piece (8), and the other ends of said lifting rods are pivotally connected each to their keel strut (3c, 3d, 3h, 3i) associated to each keel half (2a, 2b). 4. The keel as claimed in Claim 1 or 2, characterized in that said power transmission system includes a power unit (6) which vertically displaces a rod (7), in whose lower end a horizontal cross-piece (32) is fixedly retained, and in which the shafts (31b-c) of said keel halves are journalled, and at least one upwardly-directed lifting rod (34a-f) for each keel half (2a, 2b), said lifting rods being, at their lower ends, pivotally journalled each to their keel half (2a, 2b) and the other, upper end of said lifting rods is pivotally journalled to a portion (5) which is fixed in relation to the boat. 5. The keel as claimed in anyone of Claims 3-4, characterized in that the pivoting points (14a-d, 33b, 33c, 33e, 33f) of said lifting rod ' s in each respective keel half (2a, 2b) are located more distal ly from the vertical " central plane of said keel than that pivoting point (4a, 4b, 31a-c) about which each respective keel half is pivoting. 6. The keel as claimed in Claim 3, 4 or 5, characterized in that said cross-piece (8) has been provided with a guide (29, 30) for reducing the torque and flexural moments of force which outer forces may generate on said power transmission system. 7. The keel as claimed in Claim 4, characterized in that the upper ends (35a-f) of said lifting rods are pivotally journalled in a frame (5) which, in its turn, is fixedly bolted in the boat hull by bolts (10), while the lower pivoting points (33a-f) of said lifting rods in each respective keel half (2a, 2b) are movable in relation to said frame (5), like the shafts (31a-c) of said keel halves when said power unit (6) displaces said rod (7). 8. The keel as claimed in Claim 3, characterized in that the horizontal, longitudinally directed shaft (4a, 4b), or the shafts disposed in side-by-side relationship about which said keel halves (2a, 2b) are pivoted, are journalled in a frame (5) which, in its turn, is fixedly bolted to the boat hull by bolts (10). 9. The keel as claimed in anyone of Claims 3-8, characterized in that the underside of said cross-piece (8, 32) lies approximately " in the same plane as the undersides of said keel halves (2a, 2b) when these are located in their separated, horizontal positions. 10. The keel as claimed in Claim 3 or 4, characterized in that said keel halves (2a, 2b) may, in their mutually abutting position, be fixedly locked by means of a horizontally directed locking hook (16) which is placed in a recess (17) on the one keel half (2a) and may, by means of a torque transmission system, be caused to rotate about a vertical axis and hook into a locking eye (19) on the second keel half (2b). 11. The keel as claimed in Claim 10, characterized in that said torque transmission system includes an upper torsion bar (24) extending through the boat hull, and a lower torsion bar (20) located wholly within the one keel half and connected to said locking hook (16), the lower end (26) of said upper torsion bar being of non-circular cross-section, and said lower end (26) being normally located above the upper side (23) of said keel half (2a) when said keel half (2a) is in its vertical position, while the upper end of said lower torsion bar is provided with a recess (21) of a cross-sectional configuration which may cooperate with the end (26) of said upper torsion bar. 12. The keel as claimed in Claim 11, characterized in that said upper torsion bar (24) is spring-biased upwardly, such that a force is required so as to cause its lower end (26) to cooperate with a corresponding recess (21) in the upper end of said lower torsion bar (20).

Inventors: VUORENMAA PAULI, VUORENMAA, PAULI
Applicants: VUORENMAA PAULI, VUORENMAA, PAULI
Application year: 1987
Main classification: B63B41
IPC codes: B63B41