Abstract:
A drive train for an amphibious vehicle provided with a propellor disengaging mechanism aft of the transfer case, thus allowing the output drive shafts to be continuously driven at all times. The drive train includes a motor attached to a transmission which is attached to a transfer case. The attachments are accomplished by rotatably coupled drive shafts. The drive train transfers rotational movement from the motor to the transmission, then to a transfer case where it is output to the various drive shafts enabling the vehicle to be propelled on land and in water.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    The present application is a continuation of U.S. application Ser. No. 09/596,496, entitled “Amphibious Vehicle Drive Train”, filed Jun. 19, 2000, now U.S. Pat. No. 6,575,796. 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    The present invention relates to a drive train for an amphibious vehicle and, more particularly, to a drive train where all of the drive shafts are continuously rotating and a propellor engaging mechanism exists aft of the transfer case for engaging and disengaging the propellor.  
           [0004]    Amphibious vehicles present unique design challenges. Unlike cars and trucks, which are designed specifically to be driven on the land, and boats, which are designed specifically to be driven in water, amphibious vehicles must be designed to handle both tasks equally well. When driven on land, the body of an amphibious vehicle must drive like an ordinary road vehicle. On the other hand, when the amphibious vehicle is propelled in water, the vehicle must have the ability to maneuver like a boat. Therefore, the vehicle has to be provided with a propulsion system which drives both on land and in water.  
           [0005]    In the past, a dual propulsion system was achieved by using a switching mechanism on the transfer case to allow the drive system to be used either for land or water. The switch allowed the propulsion system to drive the boat on land as well as in water, but had to be switched between the two. This type of arrangement needed a complex transfer case and switching mechanism to allow for transformation between the two. One such complex transfer case can be found in U.S. Pat. No. 5,562,066.  
           [0006]    Another dual propulsion system was achieved by adding a small, two-speed transfer case between the primary transfer case and the transmission. This allowed the propellor to be driven off one shaft and the other shaft run to a second transfer case where it was then directed to the driving wheels. However, due to the short distance available between the rear of the transmission and the front of the main transfer case, it is difficult, if not impossible, to place any new or larger components in this limited space. The additional gearbox was located in this region of limited space and thus two very short drive shafts were provided. This configuration is very cramped and does not allow use of the very large truck-style automatic transmissions that are needed to transfer power of the large engines that are employed. More specifically, due to limited area between the transfer case and the automatic transmission, there is not enough room for the additional gear box and the large truck-style automatic transmissions and thus, the present invention arose.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    Accordingly, it is an object of this invention to provide a simple amphibious propulsion system which operates both amphibious and ground drives wherein a simple transfer case can be utilized without any complex switch to select between land use or marine use.  
           [0008]    Another object of this invention is to provide an amphibious propulsion system consisting of only one transfer case whose outputs continuously drive both the land and marine functions.  
           [0009]    Another object of this invention is to provide a disengaging mechanism for the propellor located aft of the transfer case to allow the propellor shaft to be disengaged when not in use.  
           [0010]    A still further object of this invention is to position the components of the drive train rearwardly to add further balance to the vehicle.  
           [0011]    Accordingly, the present invention provides for a simple amphibious propulsion system including a drive train which is capable of propelling the vehicle on land and in water. The drive train comprises a motor rotatably coupled to a transmission via a drive shaft. The transmission is then rotatably coupled to a transfer case using another drive shaft. Each output drive shaft of the transfer case continuously run while the vehicle is in operation. Although the drive shafts are continuously rotating, an engaging mechanism for the propellor is located aft of the transfer case and before a gearbox to disengage the propellor when not in use.  
           [0012]    Further objects, features, and advantages of the present invention over the prior art will become apparent from the detailed description of the drawings which follows, when considered with the attached figures. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0013]    The objects and features of the invention noted above are explained in more detail with reference to the preferred embodiments illustrated in the attached drawing figures, in which like reference numerals denote like elements, and in which:  
         [0014]    [0014]FIG. 1 is a side elevation view of an amphibious vehicle, parts broken away and in cross section to show the drive train of the present invention;  
         [0015]    [0015]FIG. 2 is an enlarged side elevation view of the drive train of FIG. 1 removed from the amphibious vehicle;  
         [0016]    [0016]FIG. 3 is a top plan view of an amphibious vehicle of FIG. 1, parts broken away and in cross section to show the drive train of the present invention;  
         [0017]    [0017]FIG. 4 is an enlarged top plan view of the drive train of FIG. 2. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    Referring now to the drawings in more detail and initially to FIGS. 1 and 3, numeral  10  generally designates an amphibious vehicle. The amphibious vehicle  10  has a body  12  constructed so that the vehicle  10  has the ability to operate on land and in water. The body  12  has a motor  14  attached to the body  12  in a manner well-known in the art.  
         [0019]    The motor is connected to a transmission  18  by a drive shaft  16 . The transmission  18  is rotatably coupled to a transfer case  22 , by a drive shaft  20 . The transfer case is attached to the body and is constructed in a manner well-known in the art. The transfer case  22  has multiple outputs which operate both the land and marine drives.  
         [0020]    The body  12  has a set of front and rear wheels,  28  and  34  respectively. The front wheels  28  are rotatably coupled to a front wheel drive shaft  24  in a manner well-known in the art. The rear wheels  34  are rotatably coupled to a rear wheel drive shaft  30  in a manner well-known in the art. The front and rear wheel drive shafts,  24  and  30  are outputs from the transfer case. The transfer case  22  is also rotatably coupled to a gearbox  38  via drive shaft  36 . The gearbox drives a propellor system  39 . The propellor system  39  consists of a first propellor drive shaft  40 , a second propellor drive shaft  42 , and a propellor  44 .  
         [0021]    [0021]FIGS. 2 and 4 are enlarged views of a drive train  15 . The drive train  15  includes the transfer case  22  and a disengaging assembly  48 . The transfer case  22  receives the output drive shaft  20  from the transmission. The transfer case has continuously rotating output shafts  24 ,  30 , and  36 . The front wheel drive shaft  24  is rotatably coupled to the front wheels in a manner well-known in the art. The rear wheel drive shaft  30  is rotatably coupled to the rear wheels in a manner well-known in the art. The final output drive shaft  36  is rotatably coupled to a disengaging assembly  48  and used to drive the propellor system  39 . By locating the disengaging assembly  48  aft of the transfer case, all drive shafts are allowed to run continuously, but the ability to disconnect the propellor system  39  still exists.  
         [0022]    The disengaging assembly  48  consists of a cable pull  46 , a pivot point  50 , a cable attach lever  56 , a gear collar  54 , and a coupler  52 . The disengaging assembly  48  attached to the coupler  52  is the input to the propellor gearbox  38 . The gearbox  38  is a speed increasing type. More specifically, it speeds up propellor  44  in a manner such that the speed of the vehicle  10  in water is comparable to the speed the vehicle  10  would be traveling on land with the rotation of the wheels. This allows the vehicle  10  to move from water to land at the same speed allowing a smooth transition for egress. The gearbox  38  is constructed in a manner well-known in the art such that the rotational speed of first propellor shaft  40  and thus propellor  44  is greater than the rotational speed of shaft  36 . The gear ratio in the gearbox  38  is constructed such that the vehicle travels through the water at approximately the same speed it would travel over land, thus resulting in the smooth transition from water to land. The output from the gearbox  38  is the first propellor drive shaft  40 , a part of the propellor system  39 . The propellor system is seen in FIGS. 1 and 3. This assembly allows the propellor  44  to be disengaged while the output drive  36  to the propellor system is still rotating.  
         [0023]    In operation, the amphibious drive system  15  derives its power from a motor  14 . The motor  14  drives the transmission via drive shaft  16 . The transmission is then connected to the transfer case  22  by drive shaft  20 . The transfer case has multiple output drive shafts which continuously rotate. Drive shafts  24  and  30  drive the front and rear wheels  28  and  34 , respectively. Drive shaft  36  is rotatably coupled to disconnect assembly  48  and drives the gearbox  38 . The disconnect assembly  48  can be selectively engaged or disengaged to the propellor gearbox  38  in the manner described below.  
         [0024]    To engage the propellor  44 , the vehicle  10  must be at a complete stop. The T-handle cable  46  is then pulled moving the cable attach lever  56 . The cable attach lever  56  moves about the pivot point  50 , which is fixed at a bracket  58 . The cable attach lever is a J-shaped lever which is attached to the gear collar  54 . The vehicle  10  is then allowed to roll forward allowing the drive shaft  36  to rotate at the proper speed and align the teeth for proper engagement. The gear and spline combination is a connection manner well-known in the art. Once aligned and with pressure applied, the gear collar  54  slips into position and the gearbox  38  is then connected to the drive shaft  36 . The first propellor drive shaft  40  on the gear box then transmits power to the propellor drive system  39 . The disengaging assembly  48  is located aft of the transfer case, but in front of the gearbox  38 .  
         [0025]    The propellor system  39  can be disengaged from the gearbox  38  by pushing the T-handle attached to cable  46  back to its original position. When the T-handle cable  46  is pushed, the cable attach lever  56  moves the gear collar  54  about a pivot point  50 . This movement disengages the gear collar  54  from the coupler  52  attached to the gearbox  38 . When the gear collar  54  is disengaged from the coupler  52  the propellor  44  ceases to rotate.  
         [0026]    From the foregoing, it will be seen that this invention is one well-adapted to attain all ends and objects hereinabove set forth together with the other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.  
         [0027]    Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative of applications of the principles of this invention, and not in a limiting sense.