Patent Publication Number: US-9403587-B2

Title: Jack plate for an outboard motor

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 13/614,407, filed Jan. 14, 2014. Issuing Jan. 14, 2014, as U.S. Pat. No. 8,627,779 which is a continuation of U.S. application Ser. No. 12/240,451, filed Sep. 29, 2008, which application claims the benefit of U.S. Provisional Application No. 60/976,243 filed Sep. 28, 2007, which applications are fully incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a mechanism for mounting outboard motors onto boats. More specifically, the present invention relates to a jack plate for vertically adjusting the trim and/or height of an outboard motor. 
     BACKGROUND OF THE INVENTION 
     During operation of a boat powered by an outboard motor, it is often desirable to raise or lower the motor. For example, when operating a boat in shallow water or removing a boat from the water with a submersible boat trailer, it is often necessary to raise the motor so that the propeller and rudder are not damaged by the bottom of the body of water. In other instances, it may be desirable to raise the motor while operating the boat at high speeds to reduce the amount of drag created by the presence of the motor in the water. 
     Adjusting the trim or height of an outboard motor can be accomplished by manipulating a set of controls operably connected to a jack plate. Although meanings of the term jack plate can vary, for purposes of this application, jack plate refers to the interfacing apparatus between a boat and an accompanying outboard motor. Generally, a component of the jack plate is fixedly mounted to the transom of the boat, while another component is mounted to the outboard motor. By operating an actuator attached to the two components, the motor can be raised or lowered in relation to the transom. A number of different types of lift actuators have been incorporated into jack plates, such as, for example, hydraulic, electric, electro-mechanical, or strictly manually operated actuators. 
     Jack plates can accomplish raising or lowering the propeller of an outboard motor by pivoting the motor about a selected point, such as at or near the top of the transom. Pivoting an outboard motor to raise the motor, however, has several drawbacks. As the motor pivots, the angle at which the propeller displaces water changes, resulting in a decrease in the propulsive efficiency of the motor. 
     Because of the drawbacks associated with tilting outboard motors, jack plates have been developed that can raise or lower the entire outboard motor in a substantially vertical direction. For example, U.S. Pat. No. 5,782,662 discloses an hydraulically powered jack plate comprising opposing supports that incorporate linear bearings in which rides a slide which is capable of vertical movement. In such vertically actuating jack plates, the points where the bearings and the lift plate are joined typically bear much of the weight of the motor. As a motor is vertically lifted out of the water, the bearings bear an even greater load as the buoyant force of the water acting upon the motor is reduced. As a result, a drawback of existing vertically actuating jack plates is mechanical failure where the bearings are joined to the lift plate. A further drawback of existing jack plates is the presence of fastening members that can result in binding between the moving parts of the jack plate. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the aforementioned deficiencies by providing a jack plate with an improved motor lift. The motor lift comprises a pair of columnar bearings that receives the vertical edges of a lift plate. Each bearing defines a channel into which the vertical edges of the lift plate can be fully inserted. The vertical edges of the lift plate and the channels within the bearings define complementary geometries such that the lift plate and the bearings are interlocking. Since the channels typically do not extend the full length of the bearings, the channels are able to substantially retain the lift plate in place and reduce—if not obviate—the need to join the bearings and the lift plate with fastening members. 
     Each of a pair of spacing brackets defines a jack plate rail having an inner geometry that conforms to the outer geometry of a bearing. A transom plate is secured to the spacing brackets such that the jack plate railings are spaced apart at a selected distance. The transom plate and the spacing brackets may also have complementary geometries. 
     When the bearings are inserted into the jack plate rails, the lift plate may be pressure fit between and within the bearings. The channels within the jack plate bearings thereby inhibit lateral movement of the lift plate in relation to the bearings, while the conforming fit of the lift plate within the channels of the bearings and/or the complementary geometries of the parallel vertical edges of the lift plate and the inner channel edges of the bearing impede vertical movement of the lift plate in relation to the bearings. 
     The lift plate can thereby be raised and lowered vertically in relation to the spacing brackets. The complementary geometries of the lift plate and the channels of the bearings, as well as the complementary geometries of the transom plate and the spacing brackets, reduce the likelihood of mechanical failure. 
     In an embodiment of the present invention, a jack plate comprises a mounting assembly having first and second spacing brackets connected by a transom plate, each of the first and second spacing brackets defining parallel channels distal to the transom plate, the transom plate being mountable to a boat transom, a motor lift including a lift plate positioned intermediate first and second bearings, each bearing defining a keyed slot adapted to receive a first or second side of the lift plate, and an actuator operably connected to the mounting assembly and the motor lift. The channels are adapted to conformingly receive the first and second bearings such that the lift plate is substantially pressure fit between the first and second bearings. 
     In another embodiment of the present invention, a boat comprises a hull having a transom, an outboard motor, and a jack plate disposed intermediate the hull and the outboard motor. The jack plate further comprises a mounting assembly having first and second spacing brackets connected by a transom plate, each of the first and second spacing brackets defining parallel channels distal to the transom plate, the transom plate being mountable to a boat transom, a motor lift including a lift plate positioned intermediate first and second bearings, each bearing defining a keyed slot adapted to receive a first or second side of the lift plate, and an actuator operably connected to the mounting assembly and the motor lift. The semi-circular channels are adapted to conformingly receive the first and second bearings such that the lift plate is substantially pressure fit between the first and second bearings. 
     In further embodiments, the channels and the bearings may be substantially cylindrical. A portion of the first spacing bracket and a portion of the second spacing bracket defining parallel channels, each portion having a substantially C-shaped cross section. The first and second spacing brackets may be adapted to removably receive the transom plate in a first direction and retain the transom plate in directions perpendicular to the first direction. The keyed slot of the first or second bearing may define at least one groove and the first or second side of the lift plate may define at least one protrusion, the at least one groove being complementary to the at least one protrusion. The lift plate may substantially define plane, the at least one protrusion extending from the first or second side in a direction substantially parallel to the plane. Alternatively, the lift plate may substantially define a plane, the at least one protrusion being proximal to the first or second side and extending substantially away from the plane. The at least one protrusion may engage the at least one groove to substantially secure the lift plate to the first or second bearing. The motor lift may further include a fastening member extending through the first or second bearing and the lift plate. At least one of the first or second bearings and at least one of the first or second spacing brackets may present opposing surfaces adapted to prevent the motor lift from disengaging the first and second spacing brackets in a downward direction. The motor lift may be adapted to be attached to an outboard motor. The first and second bearings may be made of a polymer. 
     In yet another embodiment of the present invention, a method of mounting an outboard motor onto a boat comprises forming a motor lift by positioning a plate between first and second bearings, each bearing defining a keyed slot adapted to receive a side of the plate, inserting each of the first and second bearings into a first or second channel of a mounting assembly, attaching the mounting assembly to a transom of the boat, and attaching the outboard motor to the lift plate. 
     In further embodiments, the method may include operably connecting an actuator to the mounting assembly and the motor lift. The method may also include forming the mounting assembly by disposing a transom plate to each of first and second mounting brackets. The method can include attaching the mounting assembly by attaching the transom plate to the transom. The method may further include inserting each of the first and second bearings into a first or second channel of a mounting assembly presenting surfaces of the first and second bearings that oppose top surface of first and second spacing brackets defining the first and second channels, the opposing surfaces being adapted to prevent the motor lift from disengaging the first and second spacing brackets in a downward direction. The method can also include extending a fastening member through the first or second bearing and the lift plate. In addition, the first bearing may define a keyed slot having at least one groove and a first side of the lift plate defines at least one protrusion, the at least one groove being complementary to the at least one protrusion, such that the method further includes engaging the at least one groove and the at least one protrusion to substantially secure the lift plate to the first bearing. 
     In another embodiment of the present invention, a method of controlling the trim of a boat, the boat having an outboard motor attached to a jack plate comprising an actuator operably connected to a mounting assembly and a motor lift, the mounting assembly having first and second spacing brackets connected by a transom plate, each of the first and second spacing brackets defining parallel channels distal to the transom plate, the transom plate being mountable to a boat transom, the motor lift including a lift plate positioned intermediate first and second bearings, each bearing defining a keyed slot adapted to receive a side of the lift plate, comprises actuating the actuator, sliding the first and second bearings within the channels of the mounting brackets, and maintaining the position of the first and second bearings in substantially the same position relative to the lift plate. 
     In another embodiment, the method may include preventing the motor lift from disengaging the first and second spacing brackets in a downward direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a rear view of a jack plate according to an embodiment of the present invention with an actuator; 
         FIG. 2A  is a partially exploded perspective view of a jack plate according to an embodiment of the present invention without bearings; 
         FIG. 2B  is a partially exploded perspective view of a jack plate according to an embodiment of the present invention; 
         FIG. 3  is a perspective view of a motor lift according to an embodiment of the present invention; 
         FIG. 4  is a top view of a motor lift according to an embodiment of the present invention; 
         FIG. 5  is a side view of a lift plate according to an embodiment of the present invention mounted to a boat and an outboard motor; 
         FIG. 6  is a perspective view of a lift plate according to an embodiment of the present invention; 
         FIG. 7  is a perspective view of a lift plate according to another embodiment of the present invention; 
         FIG. 8  is cross-sectional view of a bearing according to another embodiment of the present invention; 
         FIG. 9  is front view of a bearing according to the embodiment of the present invention depicted in  FIG. 8 ; 
         FIG. 10  is a cross-sectional view of a bearing according to another embodiment of the present invention; 
         FIG. 11  is a cross-sectional view of a bearing according to the embodiment of the invention depicted in  FIG. 10 ; 
         FIG. 12  is a top view of a jack plate mounting assembly according to an embodiment of the present invention; 
         FIG. 13  is perspective view of a jack plate mounting assembly according to the embodiment of the present invention depicted in  FIG. 12 ; 
         FIG. 14  is another perspective view of a jack plate mounting assembly according to the embodiment of the present invention depicted in  FIG. 12 ; 
         FIG. 15  is a perspective view of a jack plate mounting assembly according to an embodiment of the present invention; 
         FIG. 16  is a perspective view of a transom plate according to an embodiment of the present invention; 
         FIG. 17  is a perspective view of a transom plate according to an embodiment of the present invention; 
         FIG. 18  is a perspective view of a lift plate and a bearing of a motor lift according to an embodiment of the present invention; 
         FIG. 19  is an enhanced perspective view of a portion of the lift plate and the bearing depicted in  FIG. 18 ; 
         FIG. 20  is a top view of a motor lift according to an embodiment of the present invention; 
         FIG. 21  a partial cross-sectional top view of a motor lift and a spacing bracket according to an embodiment of the present invention; 
         FIG. 22  is a cross-sectional front view of a motor lift according to the embodiment of the invention depicted in  FIG. 21 ; 
         FIG. 23  is an enhanced cross-sectional front view of a portion of the motor lift according to the embodiment of the invention depicted in  FIG. 21 ; 
         FIG. 24  is a partial cross-sectional top view of a motor lift according to an embodiment of the present invention; 
         FIG. 25  is a partial cross-sectional front view at line A-A of the motor lift of the present invention depicted in  FIG. 24 ; 
         FIG. 26  is an enhanced cross-sectional top view of a portion of the motor lift according to the embodiment of the present invention depicted in  FIG. 24 ; and 
         FIG. 27  is a cross-sectional front view of a motor lift according to an embodiment of the present invention. 
     
    
    
     While the present invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the present invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention. 
     DETAILED DESCRIPTION OF THE DRAWINGS 
     The jack plate of the present invention can be mounted intermediate boat  50  and outboard motor  60  and is shown generally as jack plate  100  in  FIG. 5 . Referring to  FIG. 1 , jack plate  100  comprises motor lift  102  and jack plate mounting assembly  104 . Jack plate  100  generally also includes actuator  106 . In an embodiment, actuator  106  is an electro-mechanical ball screw actuator. In other embodiments, actuator  106  can be manual, an electrical, a mechanical or other type of actuator  106 . 
     Motor lift  102  comprises lift plate  110  and bearings  112 ,  114 , as depicted in  FIG. 1-4 . Motor lift  102  generally also includes actuator mount  116 . In an embodiment, actuator mount  116  is formed from two actuator brackets  118 ,  120 . In alternative embodiments, actuator mount  116  may be formed from a single actuator bracket or from actuator mount  116  having several actuator brackets  118 ,  120  and/or additional components. 
     Lift plate  110  has top edge  122 , bottom edge  124 , and side edges  126 ,  128 . Each side edge  126 ,  128  may be straight, as depicted in  FIG. 6 , or have tabs  130   a - c ,  132   a - c , as depicted in  FIG. 7 . In an embodiment, side edge  126  or  128  is straight. In an alternative embodiment, side edge  126  or  128  has a plurality of tabs,  130   a - c  or  132   a - c , such as depicted in  FIG. 7 . Although  FIG. 7  depicts side edges  126 ,  128  having three tabs  130   a - c ,  132   a - c  apiece, side edges  126 ,  128  may have any numbers of tabs  130 ,  132 . Tabs  130 ,  132  may be the same or different in shape. In an embodiment, tabs  130 ,  132  are the same shape and substantially square, as depicted in  FIGS. 6-7 . Lift plate  110  may also have motor-mounting apertures  134  and actuator-mounting apertures  135 . 
     In an embodiment, side edges  126 ,  128  of lift plate  110  may have tongue  306 , as depicted in  FIGS. 18-19 . Tongue  306  may also have ridge  308 . Ridge  308  may follow the entire outer perimeter of tongue  306 , as depicted in  FIGS. 18-19 . Alternatively, ridge  308  may be present on only a portion of the surface of tongue  306 . For example, ridge  308  may be present only on the sides of tongue  306 . Ridge  308  may also be present only on the top and/or bottom surface of tongue  306 . In an embodiment, ridge  308  has canted edge  312 , as depicted in  FIG. 26 . 
     Each bearing  112 ,  114  generally have outer surface  140 , top surface  142 , and bottom surface  144 . Each bearing  112  or  114  may have chamfered edge  146  between top surface  142  and bottom surface  144 . Each bearing  112  or  114  defines slot  145 . Slot  145  extends partially along length of bearing  112  or  114  to form lip  147 , as depicted in  FIGS. 8-11 . In an embodiment, slot  145  forms lip  147  below top surface  142  and above bottom surface  144 . In alternative embodiments, slot  145  forms lip  147  below top surface  142  or above bottom surface  144 . 
     In an embodiment, each bearing  112 ,  114  may also have upper portion  300  and lower portion  302 , as depicted in  FIGS. 18-19 . Upper portion  300  and lower portion  302  are generally similar in shape, but may have different dimensions. The respective shapes of upper and lower portions  300 ,  302  may, however, also be different without departing from the spirit or scope of the present invention. 
     Referring to  FIGS. 18-19 , upper and lower portions  300 ,  302  are generally cylindrical in shape. In an embodiment, upper portion  300  has a larger diameter than lower portion  302 . In this manner, each bearing  112 ,  114  presents ledge  304 , as depicted in  FIGS. 24 and 27 . One skilled in the art will readily recognize that either one or both bearings  112 ,  114  may be adapted to have ledge  304  without departing from the spirit or scope of the present invention. 
     Slot  145  has inner edge  146  and side edges  148 . Inner edge  146  of slot  145  and side edges  126 ,  128  of lift plate  110  generally have complementary geometries. For example, inner edge  146  can define grooves  150 . Although grooves  150  can be any number of sizes and shapes, grooves  150  are generally adapted to conformingly receive tabs  130  or  132  of lift plate  110 . In an embodiment, each bearing  112  or  114  has a plurality of grooves  150   a - c , such as depicted in  FIGS. 10-11 . In another embodiment, each bearing  112  or  114  has a single groove  150   a . Although the embodiments depicted in  FIGS. 8-11  have slot  145  that only partially runs the length of bearing  112  or  114 , one skilled in the art will readily recognize that inner edge  146  can define grooves  150  within slot  145  running the entire length of bearing  112  or  114  without departing from the spirit or scope of the present invention. 
     In an embodiment, slot  145  is adapted to receive tongue  306 . Generally, depth of channel  144  is sufficient to accommodate all of tongue  306 . Slot  145  may also be adapted to receive tongue  306  having ridge  308 , as depicted in  FIGS. 21-23 . Bearings  112 ,  114  are thereby able to accommodate lift plate  110  having ridges  308  on either or both sides of tongue  306 , as depicted in  FIG. 21 . Bearings  112 ,  114  are also able to accommodate lift plate  110  having ridge  308  on the top of tongue  306 , as depicted in  FIGS. 22-23 . Though not shown, bearings  112 ,  114  are similarly able to accommodate lift plate  110  having ridge  308  on the bottom of tongue  306 . One skilled in the art will further recognize that channels  144  of bearings  112 ,  114  can be adapted to receive any number of combinations of tongues  306  and/or tabs  130 ,  132  without departing from the spirit of scope of the present invention. 
     Jack plate mounting assembly  104  comprises spacing brackets,  160 ,  162  and transom plate  164 , as depicted in  FIGS. 12-15 . Jack plate mounting assembly  104  can also include actuator mount  165 . Spacing brackets  160 ,  162  are generally mirror images. Each spacing bracket  160  or  162  has jack plate rail  166 , side wall  168 , and transom wall  170 . A portion of Jack plate rail  166  defines C-shaped channel  172  and presents top surface  174 . C-shaped channel  172  is substantially cylindrical and has slit  176 . Slit  176  extends the length of jack plate rail  166 . Generally, the width of slit  176  corresponds with the width of lift plate  110 . 
     In an embodiment, C-shaped channel  172  also has a radius substantially similar to the radius of bearings  112 ,  114  such that bearing  112  or  114  can conformingly fit within jack plate rail  166 . In another embodiment, C-shaped channel  172  has a radius that is substantially similar to the radius of lower portion  302  of bearing  112 ,  114  but smaller than the radius of upper portion  300  of bearing  112 ,  114 . In accordance with this embodiment, lower portion  302  of bearing  112 ,  114  can fit within C-shaped channel  172 , but upper portion  300  cannot. Ledge  304  that is created by the difference in radii between upper and lower portions  300 ,  302  thereby substantially prevents bearings  112 ,  114  of motor lift  102  from passing completely through C-shaped channels  172  in a downward direction. 
     Transom wall  170  has front side  180  and rear side  182 . Front side  180  can have elevated region  184  and recessed region  186 . Elevated region  184  and recessed region  186  generally define parallel planes, as depicted in  FIGS. 13-14 , such that elevated region  184  and recessed region  186  are set apart. In an embodiment, recessed region  186  extends into elevated region  184  to form inlet  192 , as depicted in  FIG. 20 . Inlet  192  can receive a portion of transom plate  164 . Transom wall  170  has transom-mounting apertures  190  and bracket-mounting apertures  192 . Referring to  FIGS. 13-14 , transom-mounting apertures  190  extend through elevated region  184  and bracket-mounting apertures  192  extend through recessed region  186  in an embodiment. 
     Extending between jack plate rail  166  and transom wall  170  is side wall  168 . Side wall  168  defines top edge  200  and bottom edge  202 . Side wall  168  can be slanted upward from transom wall to top surface  174  of jack plate rail  166 , as depicted in  FIGS. 13-14 . The angles of incline of top and bottom edges  200 ,  202  can be the same or different and are between approximately zero degrees and forty-five degrees. Generally, the angles of incline of top and bottom edges  200 ,  202  are substantially similar to the angle of decline of the transom on which jack plate  100  is mounted. In an embodiment, the angles of incline of top and bottom edges  200 ,  202  are the same and are approximately twelve degrees. In another embodiment, the angle of incline of top edge  200  is thirty-five degrees and the angle of incline of bottom edge  202  is thirty degrees. 
     Referring to  FIGS. 15-17 , transom plate  164  has transom-interfacing surface  209 , top edge  210 , bottom edge  212 , side edges  214 ,  216 , and back surface  217 . Transom plate  164  also has a plurality of actuator-mounting apertures  218 , transom-mounting apertures  219 , and spacing bracket-mounting apertures  220 . In an embodiment, side edges  214 ,  216  have retaining flanges  222 ,  224 , as depicted in  FIGS. 16-17 . Retaining flanges  222 ,  224  may be the same or different in shape. Generally, retaining flanges  222 ,  224  are the same shape and substantially rectangular, as depicted in  FIGS. 16-17 . In addition, retaining flanges  222 ,  224  are adapted to conformingly fit within inlets  192  of transom wall  170 . In an alternative embodiment, side edges  214 ,  216  do not have retaining flanges  222 ,  224 . Although  FIGS. 16-18  depict transom plates  164  having only two retaining flanges  222 ,  224  or no retaining flanges  222 ,  224 , one skilled in the art will readily recognize that side edges  214 ,  216  of transom plate  164  can have any number of retaining flanges  222 ,  224  in any number or shapes that would fit within inlets  192  of transom wall  170  without departing from the spirit or scope of the present invention. 
     Transom plate  164  may have actuator mount  165  attached to back surface  217 . Actuator mount  165  can be formed from two actuator brackets  230 ,  232 , as depicted in  FIGS. 12-14 . In alternative embodiments, actuator mount  165  may be formed from a single actuator bracket or from an actuator mount assembly having a several actuator brackets and/or additional components. 
     The various components of jack plate  100  can be made from any number of materials. Generally, lift plate  110 , spacing brackets  160 ,  162 , and transom plate  164  are made from a metallic material such as, for example, steel or aluminum. Although bearings  112 ,  114  can also be from any number of materials, bearings  112 ,  114  are generally made from a low-friction polymer. Although the polymer material from which bearings  112 ,  114  are made may be rigid, it is generally at least slightly elastic. For example, some degree of elasticity may be necessary for bearings  112 ,  114  to receive and retain lift plate  110  having tongue  306  with ride  308 . In an embodiment, lift plate  110 , spacing brackets  160 ,  162 , and transom plate  164  are made from steel and bearings  112 ,  114  are made from ultra-high molecular weight polyurethane. 
     Referring to  FIG. 1 , in constructing jack plate  100 , transom plate  164  is attached to spacing brackets  160 ,  162 . Transom plate  164  is positioned on recessed region  186  such that transom-interfacing surface  209  and the surface of front side  180  of transom wall  170  are substantially co-planar and spacing bracket-mounting apertures  220  of spacing brackets  160 ,  162  are aligned with bracket-mounting apertures  192  of transom wall  170 . In an embodiment, retaining flanges  222 ,  224  are also positioned within inlets  192  of transom wall  170 . The distance between jack plate rails  166  can be varied by changing the dimensions of transom plate  164 . Transom plate  164  can be secured to spacing brackets  160 ,  162  by inserting fastening members through spacing bracket-mounting apertures  220  and bracket-mounting apertures  192 . 
     Side edges  126 ,  128  of lift plate  110  are inserted into channels  144  of bearings  112 ,  114 . Within channels, tabs  130 ,  132  of lift plate  110  are aligned with grooves  150  of inner edges  146  of bearings  112 ,  114 . In an embodiment, lift plate  110  is situated between lips  147  formed by slot  145  in each bearing  112 ,  114 . Fastening members  310  can also be secured through lift plate  110  and bearings  112 ,  114 . 
     In an embodiment, bearings  112 ,  114  can retain lift plate  110  without the use of fastening members  310 . For example, lift plate  110  having tongue  306  with ridges  308  can be inserted into bearings  112 ,  114 . Generally, the distance between ridges  308  on opposite sides of tongue  306  is slightly greater than the corresponding width of slot  145 . Ridge  308  can therefore engage grooves  130 ,  132  within slot  145  of bearing  112 ,  114 . In this manner, bearings  112 ,  114  substantially conform around tongue  306  and ridge  308  of lift plate  110 . 
     The inherent elasticity of the material from which bearings  112 ,  114  are made permit insertion and retention of ridged tongue  306 . In an embodiment, slot  145  can become wider as forced is applied to lift plate  110 . Tapered edge  312  of ridge  310  may facilitate insertion of ridged tongue  306  by gradually urging slot  145  to become wider. In another embodiment, bearings  112 ,  114  can be heated to facilitate insertion of ridged tongue  306 . By elevating the temperature of bearings, the bearing material may become more pliable, thereby facilitating elastic deformation. In addition, heating the material may cause expansion of the material, thereby widening the opening in order to accommodate insertion of ridged tongue  306 . As the material subsequently cools, bearings  112 ,  114  are able to retain ridged tongue  306  within slot  145 . In particular, the material can become more rigid and generally contract, thereby creating a conforming fit between bearings  112 ,  114  and ridged tongue  306  of lift plate  110 . 
     To further secure lift plate  110  between bearings  112 ,  114 , fastening member  310  can also be used. Referring to  FIG. 27 , fastening member  310  can be inserted into bearing  112 ,  114  and lift plate  110 . Although the embodiment depicted in  FIG. 27  shows fastening member  310  as having entered bearing  112 ,  114  through top surface  142 , fastening member  310  may also enter bearing  112 ,  114  through bottom surface  144  or outer surface  140 . In an embodiment, fastening member is countersunk within bearing  112 ,  114 . 
     Motor lift  102  is positioned within jack plate mounting assembly  102  by inserting bearings  112 ,  114  into jack plate rails  166 . In an embodiment, a lubricant is also added to bearings  112 ,  114  or jack plate rails  166 . By inserting bearings  112 ,  114  into jack plate rails  166 , motor lift  102  is pressure fit within spacing brackets  160 ,  162  of jack plate mounting assembly  104 . 
     Actuator  106  is generally attached to motor lift  102  and jack plate mounting assembly  104 . Referring to  FIG. 1 , actuator  106  is attached to actuator mount  116  of motor lift and actuator mount  165  of jack plate mounting assembly  104 . Actuator  106  is operably connected to power source  230 . In an embodiment, power source  230  provides hydraulic power. In alternative embodiments, power source  230  provides electrical or manually-derived power. 
     To install jack plate  100 , transom plate  164  is attached to the transom of boat  50  and lift plate  110  is attached to an outboard motor  60 , as depicted in  FIG. 5 . Fastening members are inserted through transom-mounting apertures  190 ,  219  of spacing brackets  160 ,  162  and transom plate  164 . Fastening members are also inserted through motor-mounting apertures  134  of lift plate  110 . 
     In operation, jack plate  100  raises and lowers the depth of motor  60  within the water through the manipulation of controls operably connected to actuator  106 , such as, for example, to adjust the trim of boat  50  within a body of water. Generally, jack plate  100  is mounted to the transom of boat  50 . Since jack plate mounting assembly  104  is fixedly attached to boat  50 , movement of actuator  106  causes a corresponding movement of motor lift  102 . Therefore, as actuator  106  is extended, motor lift  102  rises in relation to jack plate mounting assembly  104 , causing motor  60  to be raised toward the surface of the water. Similarly, as actuator  106  is retracted, motor lift  102  descends in relation to jack plate mounting assembly  104 , causing motor  60  to be lowered further below the surface of the water. 
     Jack plate  100  also provides safety features to guard against loss of motor  60  during operation. For example, it is possible that actuator  106  or actuator brackets  118 ,  120  could fail. As a result of such failure, the weight of motor  60  and/or the drag produced by a moving boat  50  may force downward. If such downward movement of motor is not sufficiently inhibited, bearings  112 ,  114  of motor lift  102  may pass completely through C-shaped channels  172 , causing motor  0  to fall from boat  50 , such as, for example, to the bottom of a body of water. Such loss may be prevented, however, by the presence of ledge  304  on bearings  112 ,  114 . If actuator  106  or actuator brackets  118 ,  120  fail during operation, for example, ledge  304  formed by upper portion  300  presents a surface that will contact top surface  142  of spacing brackets,  160 ,  162 . In that manner, motor lift  102 , as well as motor  60  attached to motor lift  102 , can be prevented from disengaging from jack plate mounting assembly  104 . If only actuator  106  fails, actuator brackets  118 ,  120 ,  230 ,  232  also can prevent loss of motor  60 . In particular, actuator brackets  118 ,  120  of actuator mount  116  and actuator brackets  230 ,  232  of actor mount  165  are generally overlapping, as depicted in  FIG. 2A-2B . Therefore, in the event of actuator  106  failure causing lift plate  110  and motor  60  to descend, actuator mount  165  interferes with actuator mount  116  such that motor lift  102  cannot pass completely through C-shaped channels  172 . 
     A feature and advantage of the present invention is the ability of jack plate  100  to resist failure or malfunction due to torque. During raising or lowering of motor  60 , as well as during operation of boat  50  when motor  60  is stationary relative to jack plate  100 , such as, for example, during turning of boat  50 , various components of jack plate  100  are subject to torque. In existing jack plates, such torque can cause slight movement among the various components. Jack plate  100  of the present invention can reduce or eliminate such movement. In particular, the union of lift plate  110  and bearings  112 ,  114  does not require fastening member  310  in accordance with some embodiments. Therefore, the torque and vibrations resulting from operation or motor and jack plate  100  can eliminate the possibility of fastening member  310  fully or partially disengaging, thereby reducing the likelihood of binding occurring between bearings  112 ,  114  and spacing brackets  160 ,  162 . 
     Torque can also cause spacing brackets  160 ,  162  to move relative to each other. This movement can result is spacing brackets  160 ,  162  being forced closer together or farther apart. When spacing brackets  160 ,  162  are forced farther apart, bearings  112 ,  114  may be urged to separate from lift plate  110 . By engaging ridges  308  on tongues  306  with appropriately configured slots  145  within bearings  112 ,  114 , the tendency of spacing brackets  160 ,  162  to separate can be resisted. Retaining flanges  222 ,  224  of transom plate  164  can also reduce relative movement between spacing brackets  160 ,  162 .