Abstract:
An inboard outboard drive is at the housing portion passing through the hull provided for sealing and damped support, with a resilient element with a non-collapsible cross-sectional shape which is subject to a constantly acting compressing force, conveniently generated by the weight of the engine. When cracks occur in the resilient element, the edges of the cracks are pressed together by this compressing force, whereby penetration of water into the hull is prevented or at least rendered more difficult. The invention is suited for application in inboard outboard drives of the S-type as well as of the Z-type.

Description:
RELATED APPLICATIONS 
     This application is related to the applicant&#39;s related applications entitled: 
     INBOARD OUTBOARD DRIVE, U.S. Ser. No. 461,877, now U.S. Pat. No. 4,501,560; and 
     INBOARD OUTBOARD DRIVE AND MOUNTING SHIELD THEREFOR U.S. Ser. No. 461,876 now U.S. Pat. No. 4,478,585, both filed on Jan. 28, 1983. 
     FIELD OF INVENTION 
     This invention realtes to inboard outboard drives and particularly a mounting device thereon for supporting on and sealing to the hull a structural part or housing of the inboard outboard drive which passes through an opening in the shell of the hull of a boat. 
     DESCRIPTION OF THE PRIOR ART 
     Inboard outboard drives are known having an inboard engine, a structural part of propeller leg, generally a casing or housing extending from the engine through an opening in the shell of the hull. The engine is connected for the transmission of torque by shafting in the structural part to the propeller mounted on an outboard portion of the structural part. 
     Two types of inboard outboard drives have been made. In one type, the generally called Z-type, U.S. Pat. No. 3,626,467, Mazziott, patented Dec. 7, 1971, the substantially horizontal output shaft of the engine, or more precisely an extension thereof, passes through an opening in the transom of the hull and enters an upper angular gear box which is located in a vertical propeller leg positioned entirely outboard of the hull. The lower end of the propeller leg provides a propeller housing. The engine output shaft is connected by the upper angular gear box, a vertical shaft in the propeller leg and a lower angular gear box and horizontal propeller shaft in the propeller housing to drive the propeller. 
     In the other type, often used as an auxiliary motor in sailboats and therefore called an S-drive, the upper angular gear box is located inboard and the vertical propeller leg or lower unit lies partly inboard, passes through an opening in the bottom of the hull to support the outboard propeller housing portion. In a special instance, the upper angular gear box is omitted in an S-drive by mounting the engine part with the output shaft positioned vertically and the engine mounted directly on the lower unit. 
     SUMMARY OF THE INVENTION 
     An inboard outboard drive having an inboard engine connected by a structural part which passes through an opening in the hull and is supported on the hull. The structural part has an outboard propeller housing portion on which a propeller is mounted. Torque transmitting means on the structural part connects the engine to drive the propeller. The structural part is not firmly or rigidly fastened to the hull to avoid the transmission of vibrations and noise from the engine and propeller to the hull. The opening is therefore made somewhat larger than the outer dimension of the structural part casing, and the intermediate space is sealed by a resilient element, e.g. a rubber bellows sleeve or annular element. 
     It will be understood that the strength and reliability of the sealing element which seals the opening in the hull is an important parameter, particularly in S-drives, because there this element is continuously exposed to water pressure on the outside. The whole boat may be filled with water if in an S-drive for some reason a crack occurs in the sealing element, a rubber bellows or a rubber sleeve. Insurance companies and other institutions therefore have particularly exacting requirements for resilient sealing elements in S-drives. 
     It is an object of the present invention to provide an improved device for mounting an inboard outboard drive in the hull and by which security against leakage is obtained by employing a resilient vibration damping supporting and sealing element for supporting the inboard outboard drive and sealing the opening between the structural part the hull constructed to support the drive and being stressed to damp the transmission of vibration and noise to the hull and stressed to close any openings or cracks to prevent leakage. 
     Though, conventionally, the support of an inboard outboard drive in the hull is arranged quite independently from the sealing sleeve, according to a preferred embodiment of the invention the engine part constantly compresses with at least a portion of its weight the uncollapsible resilient element which seals the space between the propeller and the hull, so that the dges of a possible crack cannot be pressed apart by the water pressure and allow water to flow into the hull, but instead are automatically pressed together for sealing so that the damaged boat may reach, possibly with reduced speed, the nearest convenient anchoring place. 
     The resilient element may further, due to its thickness, be made of softer material than that which is conventional in sealing sleeves and sealing bellows, whereby a better damping of vibration is obtained. The arrangement is preferably complemented by a deflection limiter, i.e., a stop means which in a selected degree limits stretching of the resilient element when casually affected or loaded in a direction opposite to the direction of compression, whereby stretching of the element beyond a permitted limit is prevented. Such affecting or loading may occur e.g. when the propeller housing strikes an underwater obstacle or when the water level at the anchoring place falls so much that the propeller housing hits the bottom. 
     It will be understood that instead of the weight of the engine part also the weight of some other structural part, or a special weight provided to this purpose may be used to constantly compress the resilient element. Gravitational force may also be combined with, or quite replaced by, some other force, e.g. spring force or magnetic attraction, by arranging spring means or magnetic and armature means between the fixing means which support the resilient element at the opposite ends thereof. 
     The resilient element may further preferably be arranged in such a manner, than when driving in the sea also the pushing force of the propeller acts thereupon in compressive direction and so temporarily, but when most needed, augments the effect of the constantly operating force. Although the invention shows the greatest advantage when applied to inboard outboard drives of the S-type, it is likewise used in Z-drives, and examples thereof will be described below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features which are believed to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of opertion, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying schematic drawings, in which: 
     FIGS. 1, 2 and 3 are partial views of a boat, each having a different types of S-drive and showing first, second and third embodiments of the invention to explain the principles of the invention; 
     FIGS. 4 and 5 are partial sectional views of a boat, each having a different Z-drive and further embodiments of the invention; 
     FIGS. 6, 7, 8, 9 and 10 are partial sectional views of five embodiments showing constructions of the resilient element and a deflection limiter according to the invention; 
     FIG. 11 is a side view with parts broken away and in axial section of an S-drive according to the invention on a reduced scale compared to FIGS. 6 to 10. 
    
    
     Structural parts with identical function are in all drawings figures denominated by identical or analogic reference signs. In the description of each figure reference is made to the prior description of identical and similar parts. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A hull 11 of a boat has according to FIG. 1 a bottom 10 and a transom 11A. The boat is provided with an inboard outboard drive 20 of the S-type with an engine part 1 and a lower unit 2 with a propeller housing part 3 which supports a propeller 4 mounted on a propeller shaft 3b. The lower unit 2 comprises an upper angular gear box 1c and a power transmission shaft 5, and in propeller housing part 3 thereof a lower angular gear box 3c is located. The engine part 1 is mounted with its output shaft 1b in horizontal position. 
     In the bottom 10 of hull 11, an opening 12 is arranged through which the lower unit 2 passes and which is somewhat larger than the cross-section of this lower unit. Around the periphery of the opening 12 a first fixing means 61 is provided which is fastened to the bottom 10 of hull 11. A second fixing means 62 is fastened to the lower unit 2 and spaced from first fixing means 61 in the direction inwards of hull 11. An annular resilient element 40 is sealingly supported in both fixing means. Element 40 is shown only schematically in FIGS. 1 and 2, and the present invention is by no means limited to the embodiment shown there. 
     The engine part 1 is at its end portion 1h which is remote from opening 12 mounted in the hull 11 in a resilient and vibration damping manner with the aid of two resilient blocks 1d, located side by side. No particular seating place is provided at the end portion 1i closest to opening 12, but engine part 1 is there via the upper portions of lower unit 2 supported by second fixing means 62 and affects through this means element 40 which is thus constantly affected by a compressing force B which in the example shown corresponds approximately to half the weight of engine part 1 plus that portion of the weight of lower unit 2 which is not compensated by the buoyance of water. The resilient element 40 is produced of conventional material, e.g. rubber, having a height H and the thickness T, and presents such a shape that will only get compressed, but will not buckle or collapse when affected by a compressive force. 
     The engine part 1 is in the example shown mounted according to applicant&#39;s three-point principle on the two resilient blocks or cushions 1d, located side by side, and on the element 40. A fixed stop 29 anchored in hull 11 as a deflection limiter, or a deflection limiter 129 provided on lower unit 2 or the propeller leg, limit the range of movement of the device or lower unit 2 in the direction inward of the hull, i.e. in the reverse direction of arrow B. 
     In FIG. 2 is shown another embodiment where the engine part 1 is mounted on four resilient blocks or cushions 1d, 1f, so that the weight thereof only to a limited extent, or not at all, affects resilient element 40. On this account, another generator of compression force is provided, such as a weight 21 and/or a compression spring 22 which is mounted between lower unit 2 and a mount 22a anchored in hull 11. 
     In FIG. 3 is shown the arrangement of an S-drive 10&#39; where engine part 1 is mounted with its output shaft 1b&#39; in vertical position on guide means 26 which is mounted on hull 11 for supporting engine part 1 in correct position without interfering with its vertical movement. The engine 1 applies, in this arrangement with all its weight, a force or load on resilient element 40. 
     In FIG. 3 is further shown that the compression force generated by engine part 1 also can be reduced, if need be, e.g. by an expansion spring 22&#39; anchored to a mount 22a&#39; and to engine part 1, and/or by a counter-weight 21&#39; which affects engine part 1 via a cable 24 passing over a pulley wheel 23 rotatably mounted on guide means 26. 
     In FIGS. 4 and 5 the mounting device according to the invention is shown in Z-drives 20&#34; and 20&#34;a. From the study of these drawing figures it will be evident that also in the operation of these mounting devices a portion of the weight of the engine part 1 affects or loads the resilient element 40 with a compression force which constantly compresses the element 40. While in an S-drive the structural part which passes outboard via the opening 12 in bottom 10 of hull 11 is lower unit 2 itself, in a Z-drive this is a link 1l which is a housing portion located between engine part 1 and lower unit 2 and which passes through opening 12 provided in the transom 11A. 
     According to FIG. 4, an inboard outboard drive 20&#34; of the Z-type comprises an engine part 1 which is mounted on four inclined resilient cushions 1d&#39;, 1f&#39; which with their upper ends slope forward in the driving direction, so that the engine part 1 has a tendency to move in the direction of arrows C, when a compression force in the direction of arrow B 1  affects the resilient element 40. When driving, the compressive effect is further increased by the propulsive force of the propeller 4. On this account the device is, besides of the earlier named limiter 29 restraining the stretch, also provided with a deflection limiter 229 which to a predetermined extent restrains the compression of the resilient element 40, e.g. on a flying start, when touching the bottom, etc. 
     According to FIG. 5, an inboard outboard drive 20&#34; of the Z-type, provided with a double propeller assembly 4, 4&#39;, is side-steerable, as shown in applicant&#39;s application U.S. Ser. No. 461,877, but otherwise fixedly mounted in a transom 11B to which the drive is attached at 11B&#39; and 11B&#34;. The drive is further provided with a double universal joint 1d. The engine part 1 is mounted in four sloping resilient cushions 1d&#34;, 1f&#34; which are inclined backwards at their upper ends, so that the engine part 1 due to its weight has a tendency to move in the direction of arrows C&#39; and a compression force in the sense of arrow B 1  &#39; acts upon the resilient element 40. Between the output shaft of engine part 1 and the shafting in lower unit 2, a spline joint 1K is provided which is shown for clarity with its connection sleeve removed and which compensates or permits the movement of engine part 1 in the sense of arrow B 1  &#39; in regard to the components of the drive which are carried by the transom 11B. The propulsive power of the propeller in this embodiment does not affect or load the resilient element 40. 
     Several examples of preferred specific embodiments of the resilient element according to the invention will now be shown in the following drawing figures. 
     According to FIG. 6, the resilient element 40, e.g. of rubber, is at its inner periphery 41i fixed to the outer perimeter of lower unit 2 and at is outer periphery 40y, which lies more forwardly in the direction of compression, to a bottom shield 70&#39; fastened to the bottom 10 of the hull, and is there retained with the aid of an annular frame 82, retaining screws 83a, and a second annular frame 83b. With the resilient element 40 (having a thickness in the order of magnitude of 2 cm) is associated an integral covering 40a for a portion of the lower unit 2, which thus is protected from corrosion and the like. This protection is further complemented by a considerably thinner sealing membrane 45 which from the outboard side shields the resilient element 40 and thus protects the underside thereof against being covered by mussels and the like and against sand being able to come through and damage the surface of the resilient element. The membrane 45 confers at the same time further security against leakage. 
     It has been stated above that for good damping of vibrations it is advantageous when the resilient element can be made of soft material. This may, however, entail that the engine jerks at start and, e.g. when driving in agitated sea moves, so that the resilient element exercises a too strong spring effect. Therefore, a deflection limiter is conveniently provided which eliminates this risk, e.g. an annular deflection limiter 329 which is made of metal, fastened to the lower unit 2, and covered by a resilient cover 145, which is advantageously integral with the sealing membrane 45. The shield 70&#39; is at its lower inner periphery provided with a land surface 171 against which the deflection limiter 329 bumps when extremely affected in the reverse sense of arrow B. 
     In FIGS. 7 and 8 are shown examples of two further preferred embodiments of annular deflection limiters which are arranged closely adjacent the resilient element 40. According to FIG. 7, an annular deflection limiter 329&#39; made of metal is provided with a resilient cover 145&#39; integral with the sealing membrane 45&#39;, and is fastened to a shield 70&#34;. Owing to the cover 145&#39;, the shocks arising upon engagement of the limiter 329&#39;, i.e. when it bumps onto an opposite land surface 2a on the lower unit 2 are damped. The deflection limiter 329&#39; is at its outer periphery, and together with the membrane 145&#39;, by retaining screws 83a&#39; fixed to the bottom shield 70&#34; which in its turn is fastened to the bottom 10 of the hull. 
     According to FIG. 8, an annular deflection limiter 329&#34; is at its inner periphery fixed to the lower unit 2 by retaining screws 83a&#34; and is covered by a resilient covering 145&#34; which is integral with the sealing membrane 45&#34;. The innermost portion of the covering defines a packing ring 145a&#34; with regard to the lower unit 2. The sealing membrane 45&#34; in its turn is with the aid of a rigid frame 71d and of retaining screws 71d&#39; fixed to a bottom shield 70&#34;a which has a land surface 171 for the deflection limiter 329&#34; and which, in a manner not shown, is attached to the bottom 10 of hull 11 (FIG. 1). 
     The resilient cover according to FIGS. 6 to 8 protects the deflection limiter against corrosion, so that the limiter may be made e.g. of metal sheet which is not protected against rust. According to FIGS. 9 and 10, which essentially is like FIGS. 5 and 6 of applicant&#39;s copending application U.S. Ser. No. 461,876, the outer perimeter of lower unit 2 is attached to inner periphery of resilient element 40. The outermost peripheric portion 40PP of resilient element 40 is with the aid of screw bolts 171C or 171C&#39; affixed to the outer peripheric portion of the bottom shield 70&#39;&#34;, and together therewith, with the aid of nuts 171b, to a bedding 11C&#39; provided in the bottom of the hull. The resilient element 40 is further supported in a shallow groove 71b&#39; in the bottom shield 70&#39;&#34; and due to said screw fixation the groove 71b&#39; has essentially only the function of taking up pressure stress by its bottom surface. A bracing element 131 defined by a rigid. e.g. metal ring with a bed profile, extends radially inwardly centrally inside resilient means 40 from their outer periphery. Adjacent the outer face of resilient means 40 which in the drawing lies upward, is a peripheric cap 231, also rigid, which has a somewhat more outward and upwards bend profile and the resilient element 40. Bracing element 131, cap 231 and an annular packing 13 are attached with the aid of the same screws 171C as the resilient means 40 and the bottom shield 70&#39;&#34;. 
     The bracing element 131, as well as the cap 231 (which conveniently also can be made of metal) may act as deflection limiting means for the elastic resilient element 40. The cap 231 has at its inner portion substantially the shape of a spherical segment cut-off by two parallel planes. Due to this shape, cap 231 acts not only as a deflection limiter in axial direction (in the reverse direction of arrow B), but also in all directions which are radial in regard of arrow B, whereby maximum stability of the device is obtained also at extreme stress in any arbitrary direction. 
     It will be observed that the inner peripheric portion 231&#39; of the peripheric cap 231 overlaps a protruding flange portion 2&#39; of the lower unit 2, and that a thin flange portion 40&#39; of the resilient element 40 extends therebetween as a shock-absorber. 
     The device of FIG. 10 differs from the device of FIG. 9 in that the retaining screws 171c are longer and protrude from the cap 231. They have sleeves 140 slipped on which transmit pressure from the heads of the screws 171c&#39; to the shield 70&#39;&#34; whereby the screws 171c&#39; upon tightening of the nuts 171b are firmly anchored in the bedding 11C&#39;. On the protruding portions of the screws 171c&#39; are strong helical springs 141 slipped on which rest on the one end against the heads of the screws, and on the other end against the cap 231. Thereby are all parts through which the screws 171c&#39; pass, i.e. the packing 13, the shield 70&#39;&#34;, the resilient element 40, the bracer element 131, and the peripheric cap 231 subject to strong, but elastic pressure. 
     The purpose of this arrangement is to automatically compensate the setting, principally of the resilient structural parts which are fastened by the screws 171c&#39;. 
     FIG. 11 shows on a smaller scale an axial cross-section through an inboard outboard drive of the S-type according to the invention, which is provided with a resilient element 40 according to FIG. 6 and which is side steerable around an inclined steering axis G. This inclined steering axis G passes through the universal joint 1d owing to the fact that the bottom shield 70&#39;, in which the resilient element 40 is inserted is attached to a bedding 11C&#39;, inclined as necessary so the steering bearing provides pivotal movement on the steering axis and is mounted on the bottom of the hull. 
     While the invention has been described with respect to certain specific embodiments, it will be appreciated that many modifications and changes may be made by those skilled in the art without departing from the spirit of the invention. It is intended, therefore, by the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention.