Patent Publication Number: US-6712655-B1

Title: Adjustable engine mount bracket assembly

Description:
The invention relates to improved engine-mounting brackets for mounting an inboard engine in a power boat or other vehicles with similar structural configuration on which an engine is supported. 
     Boat manufacturers typically install new engines at the plant and often special tooling facilitates the installation process. However, when engines are replaced, repaired or otherwise overhauled such that the engine must be removed and reinstalled in the field, it is often very difficult to reinstall the engine to the mounting blocks and its attachment to the hull support, and at the same time, properly align the engine for engagement with the propeller shaft. There is also difficulty aligning and/or placing and holding bolts in place for mounting the vibration isolator due to the limited accessibility and visibility of the area where the mounting bracket assembly is attached to the boat structural hull support. The hull support is typically a raised rail or stringer, which has a generally rectangular-shaped cross-section, that is, they are typically transversely spaced-apart inverted U-shaped longitudinal load bearing stringers, which are generally parallel to the longitudinal centerline of the boat. 
     Further, special tools are typically not available to workers repairing engines or swapping out engines in the field. The combination of the lack of such facilitating tools and the difficulty of aligning the bolts for the motor mount bracket assembly, while also trying to align the engine for coupling with the propeller shaft, makes such tasks time-consuming and arduous. 
     The present invention is an engine mounting bracket assembly that is adjustable to facilitate the alignment of the fasteners and designed to facilitate the placement and holding of the bolts in place without the need for special tooling, and at the same time allowing for and facilitating an accurate alignment with the propeller shaft. The invention thereby not only reduces the amount of time it takes to align the engine to the propeller shaft but also improves the accuracy of the alignment. 
     The engine mounting brackets currently available on the market lack the necessary adjustability and versatility to be used in different installation positions, while at the same time capable of self-securing the bottom side of the vertical fastener that holds the vibration isolators to the mounting bracket. 
     The present invention solves the functional difficulties associated with currently available brackets thereby reducing the time it takes to install and properly align the engine in a new boat on the assembly line as well as reducing the cost to the boat owner when the engine is realigned by a technician out in the field. Misaligned engines can cause many types of failures. These failures can include but are not limited to, transmission coupling, bearings and seals, stuffing box, cutless bearing, propeller shaft and/or coupling. These failures are very expensive to repair and will reoccur if the engine is not aligned properly. 
     While others have tried to solve some of the above problems, they lack the right combination of adjustability, versatility of use and the self-holding vertical fastener capability of the present invention. These three features are critical in most engine installations especially those with limited accessibility. For example, the bracket assembly disclosed in U.S. Pat. No. 4,778,420 to Greenberg and owned by Ray Industries, Inc., is an encapsulating L-shaped bracket assembly that caps the stringer. There is no versatility designed in the assembly such that the assembly can be installed in any other configuration described herein, as it can only be used as an end-cap to rest on the stringer. It can not be reversed vertically or rotated to be used on the side of the stringer. Further, there is no lateral (port-starboard) and longitudinal (fore-aft) adjustability built into the bracket assembly. 
     In many applications, an example of which is depicted in the Greenberg patent noted above, it is very difficult to reach the bottom side of the fasteners. When an application requires that the horizontal portion of the engine mounting bracket be positioned across the top of the stringer, access to the bottom side is very difficult. A commonly employed procedure is that the top of the stringer is cut away to provide access to hold the bottom side of the vibration isolator fastener as disclosed in U.S. Pat. No. 5,069,414 to Smith. Another commonly employed procedure is for the installer to have to fabricate a special wrench that will fit into the small space between the bottom of the engine mounting bracket and the top of the stringer for the purpose of securing the bottom side of the vibration isolator fastener. The self-holding feature design of the present invention will allow the installer to tighten the easily accessible top of the vertical fastener (nut or bolt head) and eliminates the need for extra help or a second tool to hold the bottom of the fastener. 
     Generally, the invention is an engine mounting bracket and back plate that has slots that make it adjustable in four directions, fore and aft, (front to back), and port and starboard (side to side). The bracket assembly also self secures the bottom side of the vertical fastener that holds a vibration isolator to the bracket. The bracket can be L-shaped (long leg upwardly directed) or inverted L-shaped and is typically made of aluminum and stainless steel. 
     The L-shaped member of the bracket assembly has two intended mounting surfaces, a vertical mounting surface on the L-shaped bracket member of the assembly that is used to mount the bracket to the stringer system of the hull of the boat and a horizontal mounting surface on the other leg of the L-shaped bracket member that is used to mount the vibration isolator to the bracket assembly. 
     A back-up plate member of the bracket assembly is used in conjunction with the L-shaped member for mounting to the stringer. The vertical leg of the L-shaped member and back-up plate have a plurality of spaced-apart slots (typically 2 to 6) that run parallel to the stringer, that is, longitudinally directed. These slots make the bracket assembly adjustable (fore and aft) parallel to the stringer system. The horizontal leg of the L-shaped member has parallel spaced-apart slots that run perpendicular to the stringer system, that is, the slots are laterally oriented and aligned perpendicular to the aforementioned slots on the vertical leg, which run longitudinally and are aligned parallel to the stringer system. These laterally oriented slots allow for adjustment of the vibration isolator side to side (port and starboard). 
     The bracket assembly also includes a horizontal plate, which attaches to the underside of the horizontal leg of the L-shaped member of the bracket assembly. Attachment of the horizontal plate can typically be done with machine screws threaded into the horizontal leg of the L-shaped member. The horizontal plate has two spaced-apart laterally directed slots that align with the overlying laterally directed slots in the horizontal leg of the L-shaped member. The combination of the slots in the L-shaped member, horizontal plate and back-up plate comprise the means for adjusting fore-aft and port-starboard positioning of the engine vibration isolators/engine and for facilitating an accurate alignment of the engine to the propeller shaft. 
     The top surface of the horizontal plate, that is, the side of the horizontal plate that is intended to be in a face-to-face relationship with the horizontal leg of the L-shaped member, has two spaced-apart laterally directed recessed portions aligned with and in an overlying relationship to the two spaced-apart slots in the horizontal plate, of sufficient depth to accommodate the sliding insertion of a washer in each groove through which, a bolt shank is passed through for securing the vibration isolator flanges. Further, the recessed portions or grooves are of a width wider than the underlying slots so that the washer is shouldered on the grooved out area. The slots in the horizontal plate are sized in width to allow the bolt head (or nut) to enter each slot and to prevent the bolt head (or nut) from rotating when tightening the nut (or bolt head) from above. The stringer will prevent the bolt head (or nut) from falling out. 
     It is preferred that the back-up plate be sized in width so that when the horizontal leg of the L-shaped member and its attached underlying horizontal plate are placed on top of a stringer, that a distal end of the horizontal leg of the L-shaped member is in an overlying relationship with an upper edge of the back-up plate. This will provide additional support for the bracket assembly. 
     The present invention is also versatile. It is effective for many different installation types and requirements. It can be installed as an inverted L, where the horizontal leg of the L-shaped member lays across the top of the boat&#39;s stringer system. It can also be used in installations where the vibration isolator is mounted inboard or outboard of the boat&#39;s stringer system where the horizontal leg of the L-shaped member faces away from the stringer to which it is bolted. The above described installation methods are most commonly used when installing twin engines in the hull of a boat. Another way the present invention can be used is by installing the bracket assembly in an L-shaped fashion, that is, with the horizontal leg of the L-shaped member being at the lower side against the stringer side wall and projecting away from the stringer side wall. This method is used when installing the engine on the inboard sides of the stringer system. This is commonly used in single engine boats or the outboard stringer of twin engine boats or boats with tall stringer system and will allow the placement of the engine lower in the hull of the boat. In these latter configurations, gussets can also be added near the inside outer edges of the L-shaped member, should additional strength be desired. Gussets can be attached by a number of ways known in the art such as by welding during manufacturing of the bracket assembly, or the gussets can be of sufficient thickness so as to attach the gussets with machine screws, where the head of the machine screw is recessed in the L-shaped member so as not protrude and interfere with the installation. Detachable gussets are recommended for the manufacture of a universal bracket system that will accommodate a number of installation configurations and requirements. 
     The versatility of the present invention allows the boat builder to install many different types and sizes of engines in the hull of a boat without having to relocate or modify the stringer system or to design a custom engine mounting bracket to accommodate each engine. 
     Before any engine mounting bracket can be bolted in place, the proper position relative to the boat&#39;s stringer system must be determined. This can be done in a variety of ways. The best method will be determined by the installer. Once the proper position is determined, the installer will drill horizontal holes in the boat&#39;s stringer that correspond to the slots in the vertical leg of the L-shaped member of the bracket system as well as the back-up plate. The L-shaped member and the back-up plate can then be bolted in place, sandwiching the stringer in between. The vibration isolator can then be placed on top of the slots in the horizontal leg of the L-shaped member. A washer can then be placed in each groove on the top surface in the horizontal plate that bolts to the underside of the horizontal leg of the L-shaped member. A bolt is then placed in the slot of the horizontal plate, through the washer, through the slot in the horizontal leg and finally through an aperture (typically a slot) in the flange or mounting pad portion of the vibration isolator. The process is repeated for the second fastener to secure the opposite flange of the vibration isolator. The bolts can be loosely tightened for later tightening. The process is completed for each engine mount. When the horizontal leg overlays the top of the stringer, the bolts and washers can be pre-installed before the L-shaped member is attached to the stringer. Two nuts are typically threaded on each mounting stud of the vibration isolator and a flat washer is typically placed over the uppermost nut. The lower nut acts as a locking nut. The engine can then be lowered into place on top of the studs that secure the engine to the vibration isolators. If necessary, spacer plates with slots that correspond in alignment to the slots in the horizontal plate and the horizontal leg of the L-shaped member can be inserted between the top of the horizontal leg of the L-shaped member and the bottom surface of the mounting pad portion of the vibration isolator to adjust the height of the vibration isolator. The engine and transmission can then be aligned to the propeller shaft coupling in the hull of the boat. When the alignment has been completed, all the fasteners can then be tightened securely. 
     The variety of available configurations presented by the design of the present invention allows the present invention to be used in a wide range of boat and stringer combinations as well as with different engines. 
    
    
     In the accompanying drawings: 
     FIG. 1 is an exploded view of the typical components of the present invention; 
     FIG. 2 is a depiction of the components of FIG. 1 further depicting the relationship of the stringer between the back-up plate and the L-shaped member; 
     FIG. 3 is a depiction similar to FIG. 2 with the addition of gussets and of a spacer plate or optional thickness plate(s) between the vibration isolator and the L-shaped member; 
     FIG. 4 is a side elevation depiction emphasize one embodiment where the gusset can be welded to the L-shaped member in lieu of bolting as shown in FIG. 3; 
     FIG. 5 is a depiction of a typical installation where the top of the bracket assembly L-shaped member is essentially level with the top of the stringers; 
     FIG. 6 is a depiction similar to that of FIG. 5 with an elevated installation of the bracket assembly; 
     FIG. 7 is a depiction of another optional installation configuration with the L-shaped member inverted against the stringers to facilitate a lower profile installation of the engine; 
     FIG. 8 is a schematic representation of the installation of the bracket assemblies to support a dual engine installation, where the L-shape member horizontal legs extend over the top of the stringers; and 
     FIG. 9 is another representative depiction similar to that of FIG. 8, except the horizontal legs are essentially flush with the top surface of the stringers and/or inboard of the stringers, and is a configuration typically used when vibration isolators are placed inboard of stringers for mounting a narrow engine or when stringers are spaced far apart. 
    
    
     Referring now to the drawings, FIGS. 1-9, the present invention is an engine mounting bracket assembly, and is depicted generally as  10 . More particularly, it is a bracket assembly  10  for securing an engine mount vibration isolator  12  and for mounting an inboard engine (not shown) on an engine support platform  14 . Although the invention was originally designed for facilitating installations of engines on boats, for which in this application, the “engine support platform” is the hull or bilge area of a boat from which the stringers extend upwardly, it is foreseeable that other types of “vehicles” may have engines mounted in such a way that the present invention would be considered very useful. 
     The stringers  16  are load-bearing structural supports and are essentially transversely spaced-apart U-shaped longitudinal load-bearing structures, parallel to a longitudinal centerline of the engine support platform  14 . 
     The bracket assembly  10  has an L-shaped member  18  of predetermined length comprising a horizontal leg  18   a  and a vertical leg  18   b , the vertical leg  18   b  for selectively mounting against either side of one of the U-shaped stringers  16 . The horizontal leg  18   a  has an upper surface  18   c  for mounting a vibration isolator  12 . 
     The L-shaped member is essentially an angle-shaped channel stock material made from preferably stainless steel or aluminum, although it is anticipated that with today&#39;s polymer-carbon fiber composite technology that it could be designed to be made from such material as well. Certainly the back-up plate  20 , horizontal plate  26  and/or the spacer plates  32  described in more detail below could be made from such polymer-carbon fiber composite material. 
     The back-up plate  20  is a plate approximately the length of the L-shaped member  18  and approximately the width of the vertical leg  18   b  of the L-shaped member  18 . It is placed on the other side of the stringer (opposite the side to which the L-shaped member is placed) thereby sandwiching the U-shaped stringer  16  between the vertical leg  18   b  and the back-up plate  20 . 
     The L-shaped member can be mounted with the horizontal leg  18   a  on the upper side or inverted, for lower profile installations, as schematically depicted in FIG.  7 . 
     The back-up plate  20  and the vertical leg  18   b  of the L-shaped member  18 , each have an array of spaced-apart longitudinal slots  22 , the slots  22  of the back-up plate  20  corresponding to and aligning with the slots  22  of the vertical leg  18   b . The array of slots  22  in each of the back-up plate  20  and the vertical leg  18   b  of the L-shaped member  18  may include two parallel spaced-apart rows of slots. One row may have one long slot or two or three spaced-apart longitudinal slots and the other row may have one long slot or two or three spaced-apart longitudinal slots. The drawings show one example of one row of three slots and one row of two slots. Certainly, other array arrangements are contemplated and not all slots need be used for bolting the bracket assembly  10  to the stringers  16 . The recommended arrays of two rows of two slots each, three slots each or alternative 3 and 2 (depicted in drawings for example purposes only) or 2 and 3 slots, provide very flexible alternatives to accommodate various installation configurations. Slots  22  depicted in the array shown in the drawings may, for example, be approximately {fraction (9/16)} inches in width and approximately 1⅛ inches in length. 
     The horizontal slots  22  in the back-up plate  20  and vertical leg  18   b  thus provide for longitudinal (fore-aft) adjustment to facilitate alignment of the engine in this particular direction before final fastening in place using fasteners  36 . 
     The horizontal leg  18   a  of the L-shaped member  18  has two transversely oriented parallel spaced-apart slots  24 . These transversely oriented slots  24  align with corresponding fastener apertures  12   a  in a mounting pad portion  12   b  of the vibration isolator  12 . 
     A horizontal plate  26  has an approximate width and length sufficient for overlaying in a face to face relationship with selectively, one of either side of the horizontal leg  18   a  of the L-shaped member  18 . For example, FIG. 7 depicts the horizontal plate  26  on the opposite side as the depictions shown in the other drawings. The horizontal plate  26  has two transversely oriented parallel spaced-apart slots  26   a  located to align with the corresponding fastener apertures  12   a  in the mounting pad portion  12   b  of the vibrator isolator  12  and the transversely oriented parallel spaced-apart slots  24  in the horizontal leg  18   a  of the L-shaped member  18 . The combination of these transversely oriented slots provides for lateral (side to side) adjustments for facilitating the alignment of the engine installation. Again, these slots may, for example, be about ½ inch in width and approximately 2¼ inches in length. 
     The horizontal plate  26  further has two spaced-apart transversely directed recessed portions  26   b . Each recessed portion  26   b  is aligned with the corresponding transversely oriented slot  26   a  in the horizontal plate  26  and extends from at least one edge of the horizontal plate  26  past the transversely oriented slot  26   a . Further, each recessed portion  26   b  has a width and depth sufficient to slide therein a washer  28 , through which a shank of a fastening bolt  30  is to be inserted as it passes through the corresponding transversely oriented slots  26   a  in the horizontal plate  26  and transversely oriented slots  24  in the horizontal leg  18   a  of the L-shaped member  18 . The recessed portion  26   b  is also located on a surface of the horizontal plate  26  which abuts in the face to face relationship with the horizontal leg  18   a  of the L-shaped member  18 . For example, with the slots  26   a  about the size noted above, the typical size of the recess portion  26   b  may be about 1⅜ inches wide, ⅛-{fraction (3/16)} inch in depth, and may run the width of the horizontal plate  26  from one side to the other or end near the edge of the opposite side. 
     The two transversely oriented parallel spaced-apart slots  26   a  in the horizontal plate  26  also have a width sufficient to prevent a head of the fastening bolt  30  from rotating when engaging a mating nut  30   a  to a threaded end of the fastening bolt or to prevent a nut  30   a  from rotating when a threaded portion of a fastening bolt  30  is threaded into the nut  30   a . With this feature, a second socket or wrench is not needed to hold the bolt or nut as it is being tightened. In tight areas, accessibility with standard tools is almost impossible, so special tooling (generally expensive) is needed. This feature eliminates the need for such additional tooling, thereby making the installation quicker and easier, especially on the hands and wrists. 
     As noted above, the horizontal plate  26  may be threadedly engaged with the horizontal leg  18   a  of the L-shaped member  18  from either side of the horizontal leg  18   a  of the L-shaped member  18 , using screw  26   d  through  26   e  threaded aperture in horizontal leg  18   a . In either configuration, the horizontal plate includes a notched out corner  26   c  along one longitudinal edge of the horizontal plate  26 . This notched out corner  26   c  is a means for avoiding interference with the inside corner  18   d  of the L-shaped member  18  when the horizontal plate  26  is placed in the face to face relationship with the inside surface  18   e  of the horizontal leg  18   a  of the L-shaped member  18 . Although the drawings depict a 90 degree notch, the corner can be notched in other ways, such as a beveled corner, as long as the plate does not ride upward against the generally typical rounded inside corner of the angle iron form comprising the L-shaped member. 
     If height adjustment is necessary beyond that, which can be accomplished by inverting the L-shaped member, and especially when the height of the vibration isolator has to be increased, one or more spacer plates  32  can be installed. Each spacer plate can be provided in various predetermined thicknesses for selective use as shims to raise the vibration isolator. The spacer plate(s) are inserted between the horizontal leg  18   a  of the L-shaped member  18  and the mounting pad portion  12   b  of the vibration isolator  12 . Each spacer plate  32  further has transversely oriented slots  32   a  in alignment with corresponding slots  24 , 26   a  in the horizontal leg  18   a  of the L-shaped member  18  and the horizontal plate  26 . The spacer plates  32  may typically be ⅛ inch, ¼ inch, ⅜ inch, ½ inch, ⅝ inch, ¾ inch, ⅞ inch, 1 inch, etc. Any combination and any fractional dimension of the preceding thicknesses may also be used. The spacer plates  32  may be made from a variety of materials from steel, stainless steel and aluminum to polymer base composites, including fiber reinforced polymeric-carbon fiber composites. 
     In certain situations, an L-shaped member  18  having inside gussets  34  near each of the inside outer edges  18   f  of the L-shaped member  18  may be desirable for additional strength. The gussets  34  may be made from a variety of materials from steel, stainless steel and aluminum to polymer base composites, including fiber reinforced polymeric or carbon fiber composites. The gussets  34  can either be fixed such as pre-welded (for gussets made from metal materials) as depicted by  34   a  in FIG. 4, or the gussets may be removably attached to the L-shaped member  18 , using screws, such as the cap screws  34   b  depicted in FIG.  3 . The latter is desirable, especially if the present invention  10  is sold as a field kit, with various combination of spacer plates  32 . A field kit is especially desirable for mechanics in the field needing to install repaired or new engines. 
     It should be understood that the preceding is merely a detailed description of one or more embodiments of this invention and that numerous changes to the disclosed embodiments can be made in accordance with the disclosure herein without departing from the spirit and scope of the invention. The preceding description, therefore, is not meant to limit the scope of the invention. Rather, the scope of the invention is to be determined only by the appended claims and their equivalents.