Abstract:
A boat trailer modified to include a load-bearing trolley and a track; the trolley is movable along the track along a direction parallel to the length of the trailer, and the ends of the track correspond to the fully launched and fully loaded positions of the boat on the trailer. A belt with ends attached to the ends of the trolley is moved by a sprocket connected to a hand crank, through a set of sprockets and idler rollers. Rotating the hand crank causes the belt to move, thereby causing the trolley to move along the track, resulting in movement of the boat to either launch it into the water or load it onto the trailer. A latch mounted on a docking plate on the trolley automatically latches or releases the tow ring depending upon the position of the trolley along the track.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Serial No. 60/405,311, filed Aug. 23, 2002. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to boat trailers and, more particularly, to an improved boat trailer in which a conventional trailer is modified to include a load-bearing trolley movable along a track for greater ease in launching or loading a boat on the trailer.  
           [0004]    2. Description of the Related Art  
           [0005]    Although boat trailers have been used for a long time for launching or loading boats, known trailers generally are difficult to use in launching or loading boats. For example, to load a boat onto the trailer, the trailer must be backed-up into the body of water and then a hook must be applied to the bow ring and pulled by a winch which brings the boat into place on the trailer. Hand cranked winches are difficult to operate manually, and powered winches require greater maintenance.  
           [0006]    The instant invention is an improved boat trailer in which a conventional trailer is modified to include a load-bearing trolley movable along a track for greater ease in launching or loading a boat on the trailer. An encircling belt strip, such as a timing belt, is attached at its ends to corresponding opposite ends of the trolley. The belt strip is mounted on and is movable on a set of rollers (e.g., idlers and sprockets). One of the rollers is a hand crank that is turned manually (or, alternatively, with a 12 volt DC power winch) to transfer torque to the belt causing the trolley to move back and forth along the track, the direction of movement of the trolley depending upon the direction of rotation of the crank. A novel latch is also provided that automatically latches or releases the boat at its bow ring depending upon the position of the trolley along the track. Thus, the present invention fills the need for a boat trailer that makes loading and launching boats faster and easier than previously known trailers.  
           [0007]    A discussion of relevant art follows.  
           [0008]    U.S. Pat. No. 3,963,263 issued to Whitlock on Jun. 15, 1976 teaches an automatic boat latch. However, this latch does not provide an automatic release for use when launching the boat.  
           [0009]    U.S. Pat. No. 4,363,590 issued to Crate on Dec. 14, 1982 teaches a boat trailer using a set of powered rollers for loading and launching.  
           [0010]    U.S. Pat. No. 4,681,334 issued to O&#39;Brien, Jr. on Jul. 21, 1987 teaches a boat trailer having a telescoping stern attachment to permit easier boat launches and loadings.  
           [0011]    U.S. Pat. No. 4,781,392 issued to Cooper on Nov. 1, 1988 teaches a molded boat trailer in which the shape of the trailer conforms to the shape of the boat hull.  
           [0012]    U.S. Pat. No. 5,273,391 issued to White on Dec. 28, 1993 teaches a boat trailer including a hand-cranked bow winch.  
           [0013]    U.S. Pat. No. 5,320,058 issued to Reed on Jun. 14, 1994 teaches a boat trailer including a winch that uses an air compressor to assist in loading the boat.  
           [0014]    U.S. Pat. No. 5,511,928 issued to Ellis on Apr. 30, 1996 teaches a boat loading device that is usable on a trailer or truck bed and includes a movable load-bearing frame. The bow ring is grasped with a hook at the end of a cable connected to a winch to pull the boat onto the frame.  
           [0015]    U.S. Pat. No. 5,666,901 issued to Jones on Sep. 16, 1997 teaches a bow mounted boat latching mechanism in which the latch can be released by an occupant on the boat.  
           [0016]    U.S. Pat. No. 5,879,114 issued to Spence on Mar. 9, 1999 teaches a boat-to-trailer latch which uses a spring-loaded bolt latch.  
           [0017]    U.S. Pat. No. 5,895,066 issued to Headlee on Apr. 20, 1999 teaches a boat trailer that is connected to the vehicle hitch by a telescoping tongue that also includes a latching mechanism and a locking dog.  
           [0018]    U.S. Pat. No. 6,135,481 issued to Bishop, III et al. on Oct. 24, 2000 teaches a boat trailer in which a support mechanism is provided on either the port or starboard sides of the trailer to securely hold the boat in place or release the boat when launching.  
           [0019]    None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus an improved boat trailer solving the aforementioned problems is desired.  
         SUMMARY OF THE INVENTION  
         [0020]    The present invention is directed to a modified boat trailer, particularly, in which a load-bearing trolley that supports the boat is movable back-and-forth along a track integrally attached to the trailer. An encircling strip, e.g., a strip of a timing belt, is attached to the trolley with its two ends attached to the corresponding ends of the trolley. The strip encircles a set of rollers, e.g., sprockets, and a hand crank that can be turned manually (or with a 12 volt DC power winch) to cause the belt to move and, therefore, to cause the trolley to move back-and-forth along the track.  
           [0021]    When the trailer is fully unloaded, i.e., when preparing the trailer to load the boat from the water, the trolley is positioned at the stern of the trailer, i.e., it is positioned at the stern end of the track. In this position, the trolley is ready to receive the boat. Conversely, when the trailer is fully loaded, the front of the boat rests on the trolley and the trolley is positioned toward the front of the trailer.  
           [0022]    The trolley includes a latch at its front end that connects to the bow ring of the boat to secure it on the trolley. The latch automatically latches onto the bow ring when the boat is being loaded onto the trolley. A docking plate that is fastened to the front of the trolley ensures that the bow ring centers onto the latch when the boat impinges on the trolley, which occurs at a speed typically about 1-3 knots. It also automatically releases the bow ring when the boat is being launched into a body of water.  
           [0023]    Accordingly, it is a principal object of the invention to provide a boat trailer modified to include a load-bearing trolley that is movable along a track mounted on the trailer.  
           [0024]    It is another object of the invention to provide a boat trailer modified as above in which the trolley has wheels that move inside the track and in which an encircling belt is connected to the trolley and the trolley is moved by transfer of torque from a hand-crank to the belt, which ultimately moves the trolley.  
           [0025]    It is a further object of the invention to provide the above modified boat trailer in which the encircling belt is a timing belt.  
           [0026]    It is a further object of the invention to provide a modified boat trailer as above which includes an automatic locking and releasing latch attached to the trolley.  
           [0027]    It is a further object of the invention to provide a modified trailer as above in which the trolley includes a mast attached to and oriented at an angle from the top front surface of the trolley, and a mast receiver is provided that is permanently attached to the track and in which the mast fits inside the receiver and can be locked in place using an attachment pin when the boat is fully loaded onto the trailer.  
           [0028]    It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.  
           [0029]    These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0030]    [0030]FIG. 1 is an environmental, perspective view of an improved boat trailer according to the present invention.  
         [0031]    [0031]FIG. 2 is a partial side elevational view of the trolley and belt.  
         [0032]    [0032]FIGS. 3A and 3B are, respectively, top plan and side elevational views of the track.  
         [0033]    [0033]FIG. 4A is an enlarged scale side elevational view of the trolley. FIG. 4B is an enlarged scale cross-sectional view of the trolley in its track.  
         [0034]    [0034]FIGS. 5A, 5B and  5 C are respective end, top and perspective views of the docking plate.  
         [0035]    [0035]FIGS. 6A and 6B are views showing operation of the latch.  
         [0036]    [0036]FIG. 7 is a partial detail view of the hand crank and free tensioner.  
         [0037]    [0037]FIG. 8 is a partial side elevational view of the trolley and belt according to a second embodiment of the present invention.  
         [0038]    [0038]FIG. 9 is a partial detail view of the power winch and free tensioner.  
     
    
       [0039]    Similar reference characters denote corresponding features consistently throughout the attached drawings.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0040]    The present invention is directed to a modified boat trailer. FIG. 1 shows a boat  10  held in place in its fully loaded position on the trailer generally indicated at  20 . Conventionally, boat trailers are built to fit a particular size boat. The present invention is an additional modification to permit the user to more easily load or launch the boat using a trolley and corresponding track.  
         [0041]    When fully loaded, as shown in FIG. 1, the U-bolt normally located on the bow of the boat, i.e., the bow-mounted tow ring, is held in place by a latch situated behind docking plate  200 . The aft of the boat is held in alignment on the trailer by rollers or bunks (not shown). The inventive load-bearing trolley  100  has a cushioning centering bar  90  that resiliently supports the front of the boat, and is movable along track  50  by moving a belt  60  with a hand-powered crank  80 . The crank and supporting structure is generally indicated as item  30 . At the front of the trailer is a conventional hitch  22 .  
         [0042]    Belt strip  60  is held at its ends to the front and rear top edges of the trolley  100  and elsewhere by sprockets and idler rollers as explained as follows and shown in detail in FIGS. 2 and 3A- 3 B and in FIG. 7: beginning at the front of the trolley  100 , belt  60  is fastened to the top front edge of the trolley; it then passes underneath an idler roller  58 ; through the free floating tensioner  62 ; around hand crank sprocket  82 ; passes again through the tensioner; around sprockets  54 ; and, finally, is fastened again at its opposite end to the rear top edge of the trolley  100 .  
         [0043]    Where the belt passes directly between the two sprockets  54 , it passes through the inside channel of the track between the lower portions of the left and right wheels of the trolley. Where the belt emerges out from inside the track around the stern sprocket  54 , it moves directly over the length of the slot  52  in the track along which the body of the trolley moves. This covering relationship of the belt over the slot helps to prevent debris from entering the inside of the track.  
         [0044]    At the front of the trolley  100 , a mast  112  is attached to its top surface, e.g., by welding. In the fully loaded position of FIG. 1, the trolley mast  112  is seated inside mast receiver  70 , which is permanently attached to the track. Holes  74  are provided in the mast  112  and the mast receiver  70  that allow an attachment to be inserted and held in place with keeper pins, to ensure that the fully loaded boat is securely held in place on the trailer.  
         [0045]    The track also provides support for the hand crank  30  that is operated with the handle and arm  80  to the move the trolley through the belt  60 . When the hand crank  80  is turned, it transfers torque to the belt  60 , causing it to move the trolley along the track  50 . In FIG. 3B, sprocket  82  and idler roller  58  are free to rotate, but are permanently held at the ends of their axles to the track  50  by support braces (not shown).  
         [0046]    Idler roller  58  is adjustable horizontally to take up any slack from the belt when the trolley  100  and belt  60  are first assembled into the track. Adjustment bolts  282  are used to adjust the position of the ends of the axle of roller  58  back-and-forth along a slot  280 .  
         [0047]    [0047]FIG. 4A shows details of the trolley  100 . The docking plate  200  is attached,to the upper portion of the mast  112 . Details of the docking plate are shown in FIGS.  5 A- 5 C. The docking plate is held by back supports  270  on a pair of pivots that move on both a horizontal axis (shown as pivot  242 ) as well as a vertical axis  240 . The aperture  268  in the lower portion of the docking plate receives the bow ring  230  during docking. A flexible target antenna  290  attached to the docking plate  200  allows the occupant of the boat to see the position of the docking plate/trolley when loading and to aim the boat properly to ensure that the tow ring enters the latch.  
         [0048]    Immediately behind the bow ring receiving aperture  268  in the docking plate is a latch housing  272  containing a latch, which is shown in detail in FIGS.  6 A- 6 B. The release cable  302  is attached at one end to the latch lever  260  and at the other end to the release lever  306 . The release lever  306  moves back-and-forth on pivot  308 . A tension spring  304  allows the lever to pivot without unduly stretching the cable. The release lever pivot  308  is attached to the top surface  102  of the trolley.  
         [0049]    When the trolley is cranked to the stern end of the track  50 , during launching or in preparing to load the boat onto the trolley  100 , the release lever bar  310  actuates the release lever  306  on the trolley  100 , causing the latch jaws  222  and  224  to open. When the boat is being launched, this causes the boat to be released from the trolley. Similarly, when the trolley is being placed into position to load the boat, the latch opens ready to receive the bow ring  230 .  
         [0050]    Free floating tensioner  62  is shown in detail in FIG. 7. Idler rollers  66  inside the tensioner housing  64  maintain a fixed spacing between the two moving portions of the belt  60  to take up slack.  
         [0051]    At the front and rear edges of the trolley, the ends,  104  and  106 , of a timing belt  60  are attached and held in place using a plate  72  and bolts  68  that pass through the plate, the belt end and the trolley surface. The ribs of the timing belt are shown in the cross-sectional view of FIG. 4A. Also, debris scrapers  292  and  294  are attached to the ends of the trolley that wipe debris inside the track to the ends of the track as the trolley moves. A detailed view of one of the brushes  292  is shown in FIG. 4B. The lower middle portion of the brushes is notched to permit sufficient space for the belt  60  to move freely beneath the brushes. FIG. 3B shows rubber roller  56  that is used to protect the rear of the track and the rear sprocket against damage as may occur, for example, when transporting the trailer.  
         [0052]    As shown in FIGS. 4A and 4B, the top surface of the trolley  102  is attached to the vertical body  108  of the trolley, e.g., by welding. The body of the trolley includes six wheels  252  that rotate on axles  110 . Between the trolley body  108  and the wheels  252  are spacers  250 . The height of the wheels and the width of the axles are accommodated with a narrow tolerance within the channel of the track  50 . A lubricant can be applied in the channel, if necessary.  
         [0053]    In FIGS.  6 A- 6 B, details are shown of the latch structure. Immediately prior to docking, the trolley is positioned at the stern end of the track and the bow ring  230  of the boat  10  approaches the docking plate. The latch  220  at this point is in its fully open position as shown in FIG. 6A. The boat  10  moves at approximately 1-3 knots toward the docking plate, as the bow ring enters the opening in the docking plate (see item  268  in FIG. 5C), it impinges on the latch jaws,  222  and  224 , that rotate on respective pivots,  226  and  228 , forcing the jaws to close into the position shown in FIG. 6B.  
         [0054]    The normally open latch is now closed onto the bow ring  230 , holding the bow of the boat  10  securely on the trolley  100 . In the closed position, the latch lever  260  moves on pivot  264  to cause the end  266  of the latch lever to move into the notched portions of the jaws  224  and  226  to maintain the latch in the closed position. A spring  262  maintains the latch lever  260  in the position shown in FIG. 6B until the release lever is actuated when the boat is being launched.  
         [0055]    [0055]FIG. 8 depicts an additional embodiment of the present invention. In the embodiment depicted in FIG. 8 the hand crank  80  is replaced with a 12 volt DC power winch  80   a.  The power winch  80   a  allows the trolley  100  to be automatically moved. FIG. 9 shows an enlarged view of power winch  80   a.  The power winch  80   a  is secured to the sprocket  82  above the free tensioner  62 .  
         [0056]    Exemplary dimensions for a trailer capable of holding any trailerable boat are as follows. The track can be made of 3-inch box steel having a ⅝″ slot. The trolley can be made with a horizontal top steel strip having a 0.186″ thickness welded to a vertical body having a 0.375″ thickness. The length of the trolley can be 24″. The axles holding pairs of corresponding wheels onto the trolley are 0.75″ in diameter. The wheels can be made of nylon and have a diameter of 2.625″, sufficient to fit within the channel of the track while maintaining a small tolerance to permit movement along the track.  
         [0057]    The timing belt can be L-100 and the two lower sprockets can be made of polycarbonate and designated as 24L-100, i.e., corresponding to 1″ width and capable of 400 lb load tension. The hand crank can be a forward-reverse “clicker” having a 3″ diameter L-100 timing pulley. The centering saddle on the trolley can be a rubber U-channel cut and held onto the trolley using bolts.  
         [0058]    Although dimensions and materials have been provided for an exemplary structure, alternative materials and timing belts are also contemplated. For example, in order to load or launch larger boats, a wider track, trolley and timing belt would be required.  
         [0059]    It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.