Abstract:
An adjustable speed winch includes a winch housing, a winch drum rotatably connected to the winch housing, a winch motor, a drive shaft, motor shaft coupling means, direct drive means, first gear reduction means and selection means. The motor includes a motor shaft rotating at a first speed. The motor shaft is coupled to the drive shaft by way of the motor shaft coupling means so that the drive shaft rotates at a second speed. In some embodiments, the second speed is the same as the first speed, while in some embodiments the second speed is less than the first speed. The direct drive means couple the winch drum to the drive shaft so that the winch drum also rotates at the second speed when the direct drive means is engaged. The first gear reduction means couple the winch drum to the drive shaft so that the drum rotates at a third speed that is less than the second speed when the first gear reduction means is engaged. The selection means provide for switching between the direct drive means and the first gear reduction means, the choice of which determines the rotation speed of the winch drum.

Description:
TECHNICAL FIELD 
       [0001]    The present invention is directed to a high-torque multi-speed hydraulic vehicle winch which utilizes the vehicle&#39;s power steering system as a source of hydraulic power. 
       BACKGROUND 
       [0002]    The advantages of having a winch mounted to a vehicle have long been appreciated. For off-road adventures, a winch provides a highly effective means for extraction of the vehicle when stuck in mud or when the vehicle has become high-centered in rough terrain. The winch extends the range of the vehicle by encouraging the off-road adventurer to push the vehicle&#39;s performance envelope where he would otherwise be afraid to do, and when that envelope has been exceeded, to bring the vehicle back to within its operational limitations. The winch can be used for endless other applications as well, including rescuing other vehicles from perilous mud holes, moving large objects such as felled trees and towing other vehicles. 
         [0003]    While it is necessary to have low-speed, high-torque winch operation to move heavy loads, it is often desirable to operate the winch at a higher speed to quickly take up slack in a cable before moving a load or to quickly retrieve a long length of cable after a load has been moved. Thus, a convenient and reliable means of switching between high-speed, low-torque operation and low-speed, high-torque operation in a vehicle-mounted winch is desirable. 
       SUMMARY 
       [0004]    The above and other needs are met by an adjustable speed winch that includes a winch housing, a winch drum rotatably connected to the winch housing, a winch motor, a drive shaft, motor shaft coupling means, direct drive means, first gear reduction means and selection means. The motor includes a motor shaft rotating at a first speed. The motor shaft is coupled to the drive shaft by way of the motor shaft coupling means so that the drive shaft rotates at a second speed. In some embodiments, the second speed is the same as the first speed, while in some embodiments the second speed is less than the first speed. The direct drive means couple the winch drum to the drive shaft so that the winch drum also rotates at the second speed when the direct drive means is engaged. The first gear reduction means couple the winch drum to the drive shaft so that the drum rotates at a third speed that is less than the second speed when the first gear reduction means is engaged. The selection means provide for switching between the direct drive means and the first gear reduction means, the choice of which determines the rotation speed of the winch drum. 
         [0005]    In some preferred embodiments, the motor shaft coupling means include second gear reduction means that cause the drive shaft to rotate at about one sixth (⅙) the speed of the motor shaft. In some embodiments, the first gear reduction means cause the winch drum to rotate at about one third (⅓) the speed of the drive shaft. 
         [0006]    In some embodiments of the invention, the first gear reduction means include a first pinion gear coupled to the first end of the drive shaft and a drum drive plate attached to the winch drum. A plurality of first planet gear shafts extend outward from the drum drive plate, and a corresponding number of first planet gears are rotatably coupled to the first planet gear shafts. These embodiments also include a first ring gear that is rotatably coupled to the winch housing. The first planet gears are meshed with the first pinion gear and the first ring gear. 
         [0007]    In some embodiments, the second gear reduction means include a second pinion gear coupled to the motor shaft and a drive shaft plate coupled to the second end of the drive shaft. A plurality of second planet gear shafts extend outward from the drive shaft plate, and a corresponding number of second planet gears are rotatably coupled to the second planet gear shafts. These embodiments also include a second ring gear attached to the winch housing. The second planet gears are meshed with the second pinion gear and the second ring gear. 
         [0008]    The direct drive means preferably comprise a coupling plate having a central opening that is keyed for engaging and being rotatably driven by the first pinion gear. The coupling plate includes a plurality of peripheral openings that are disposed radially about the central opening. Each of the peripheral openings are positioned to slidingly receive a corresponding one of the first plant gear shafts. 
         [0009]    The selection means preferably include means for moving the coupling plate between first and second axial positions relative to the first pinion gear. When the coupling plate is in the first axial position, the central opening of the coupling plate engages the first pinion gear so that the direct drive means is engaged. When the coupling plate is in the second axial position, the central opening of the coupling plate disengages from the first pinion gear so that the direct drive means is disengaged. 
         [0010]    Preferred embodiments of the winch are primarily for use on vehicles with power steering fluid specifications of 2500-3000 pounds per square inch (PSI) and 8-12 gallons per minute (GPM). However, the winch is fully functional even on vehicles having lower-end fluid specifications of 1500 PSI and 4 GPM. Some embodiments of the winch are also functional in industrial applications wherein flow rates are over 12 GPM, although for safety reasons, two-speed operation of the winch can be disabled for applications having such high flow rates. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Further advantages of the invention are apparent by reference to the detailed description in conjunction with the figures, wherein elements are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein: 
           [0012]      FIG. 1  depicts a cross-sectional view of a high-torque multi-speed winch according to a preferred embodiment of the invention; 
           [0013]      FIG. 2  depicts a cross-sectional view of a 3-to-1 gear reduction assembly according to a preferred embodiment of the invention; 
           [0014]      FIG. 3  depicts a cross-sectional view of a 6-to-1 gear reduction assembly according to a preferred embodiment of the invention; and 
           [0015]      FIG. 4  depicts an exploded view of a high-torque multi-speed winch according to a preferred embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]      FIGS. 1-4  depict a preferred embodiment of a hydraulic high-torque multi-speed vehicle winch  10 . The winch  10  includes a drive shaft  12  which is driven by a hydraulic winch motor  14 . The drive shaft  12  extends through the axial center of a winch drum  16  which is held in place by a motor end housing  22  and a drive end housing  24 . A mounting plate  26  provides a substrate on which the housings  22  and  24  rest when attached to a host vehicle. Bolt holes in the mounting plate  26  (shown generally at  28   a  and  28   b ) align with threaded holes in a motor end support  30  and the drive end support  32 . As shown in  FIG. 1 , the housings  22  and  24  are mounted to the base plate  26  and host vehicle by means of bolts shown generally as  34   a  and  34   b.    
         [0017]    The housings  22  and  24  are connected together by two tie rods  36   a  and  36   b . Although two tie rods  36   a  and  36   b  are provided in the preferred embodiment, it will be understood that a single tie rod can be used instead. Further, it will be appreciated that when the tie rods  36   a  and  36   b  are removed, the housings  22  and  24  and the winch drum  16  are no longer connected and can be pulled apart freely, thereby simplifying maintenance. In other words, the winch drum  16  is effectively held in place and supported by the housings  22  and  24  when the latter are connected by means of the tie rods  36   a  and  36   b.    
         [0018]    The winch drum  16  is coupled to the drive shaft  12  via reduction gearing contained within the drive end housing  24  so that the drum  16  rotates in response to operation of the winch motor  14 . In this manner, cable is released from the drum  16  as the winch motor  14  turns in a forward direction and is retrieved as the winch motor  14  turns in a reverse direction. Typical reduction gearing apparatuses and methods can be used to suitably couple the drive shaft  12  and winch drum  16 , and to provide sufficient torque output to the winch drum  16 . 
         [0019]    In a preferred embodiment, the winch motor  14  is a low-speed, high-torque motor with 160 cc capacity. Suitable sources for such motors include White Hydraulics of Louisville, Ky. and the Dan Foss Company which is located in Wisconsin. The motor  14  may be driven by the host vehicle&#39;s hydraulic pressure supply. For example, the vehicle&#39;s power steering system may be utilized to provide hydraulic pressure for operation of the winch motor  14  as described in U.S. Pat. No. 5,842,684, the full disclosure of which is incorporated herein by reference. For a typical vehicle installation where the motor  14  is powered by a vehicle&#39;s power steering system, the vehicle&#39;s power steering pump will supply hydraulic fluid to the motor  14  at a pressure of about 2500 PSI with a flow rate of about eight GPM. This installation configuration produces a maximum torque of about 36,000 lb-in on the winch drum bottom wind and a nominal drum rotation rate of about 12 RPM during winch motor operation. However, it will be understood that the maximum torque and nominal drum rotation rate will vary depending on the particular installation configuration as well as the particular gear reduction ratio employed. 
         [0020]    A preferred reduction gearing apparatus for coupling the drive shaft  12  to the winch drum  16  is illustrated in  FIGS. 1 ,  2  and  4 . The drive shaft  12  extends through the axial center of the winch drum  16  and engages an arrangement of three planet gears  18   a - c  which rotate upon three planet gear shafts  20   a - c . As shown in  FIG. 1 , one end of each planet gear shaft  20   a - c  is attached to a drum drive plate  38  which is rigidly attached to the winch drum  16 , such as by a weld. The planet gear shafts  20   a - c  are radially spaced at 120 degrees about the perimeter of the drum drive plate  38 . A pinion gear  40  at the end of the drive shaft  12  engages the planet gears  18   a - c  so that the planet gears  18   a - c  rotate in response to rotation of the drive shaft  12 . A ring gear  42  meshes with the planet gears  18   a - c  so that when the ring gear  42  is locked to the drive end housing  24  by means of a gear reduction plunger  44 , rotation of the drive shaft  12  causes the winch drum  16  to rotate at a speed slower than that of the drive shaft  12 . In a preferred embodiment, the gear reduction ratio achieved with this arrangement is three-to-one (3:1). However, it will be understood that other gear reduction ratios can be achieved with the gear reduction arrangement shown. 
         [0021]    The gear reduction plunger  44  mechanically couples the ring gear  42  to the drive end housing  24  by means of holes  46  along the outer surface of the ring gear  42 . When the plunger  44  is retracted, and thereby removed from the holes  46 , the ring gear  42  and planet gears  18   a - c  are drivingly decoupled from the winch drum  16 . In other words, retracting the plunger  44  from the ring gear  42  effectively decouples the drive shaft  12  from the winch drum  16  so that the winch drum  16  free-spools. In this manner, a free-spooling capability is provided whereby cable may be unwound from the winch drum  16  without the assistance of the winch motor  14 . This free-spooling capability is particularly useful for rapid removal of cable from the winch drum  16 . 
         [0022]    In a preferred embodiment, the gear reduction plunger  44  is urged toward the ring gear  42  by a spring  48 . To disengage the plunger  44  from the ring gear  42 , the plunger  44  is pulled in a axial direction away from the ring gear  42  by the rotation of a cam sleeve  50  to which the plunger  44  is attached. This condition is illustrated in  FIG. 1 . The cam sleeve  50  is rotated by means of a gear reduction selector handle  52  so that the winch drum  16  is made to free-spool when the gear reduction selector handle  52  is in the position shown in  FIG. 1 . When the gear reduction selector handle  52  is rotated 180 degrees clockwise from the position shown in  FIG. 1 , the ring gear  42  is locked to the housing  24 , thus disabling free-spool operation. 
         [0023]    The winch drum may be driven in a high-speed, low-torque mode by coupling the rotation of the drive shaft  12  directly to the winch drum  16  with no gear reduction. A higher drum rotation speed is useful in retrieving long lengths of unspooled cable after load-moving operations are complete, or in taking up slack in the cable prior to moving a load. In the preferred embodiment of the invention, the coupling of the drive shaft  12  to the winch drum  16  is attained by a coupling plate  54  which is moveable between two axial positions: a low-speed position in which the winch drum  16  is decoupled from the drive shaft  12 , and a high-speed position in which the winch drum is coupled to the drive shaft  12 . For the exemplary vehicle installation described above (2500 PSI at eight GPM), the direct drive arrangement produces a nominal drum rotation rate of 38 rpm and a maximum torque of 2000 lb-in during winch motor operation. 
         [0024]    As shown in  FIGS. 1 ,  2  and  4 , the coupling plate  54  of the preferred embodiment is a circular plate with a keyed opening  56  at its center. The shape of the keyed opening  56  matches the pinion gear  40  at the end of the drive shaft  12 . The coupling plate  54  also has three openings  58   a - c  that are radially spaced at 120 degrees about its perimeter. The position and spacing of these openings  58   a - c  match the position and spacing of the planet gear shafts  20   a - c  which extend from the drive drum plate  38 . With this arrangement, the coupling plate  54  is coupled to the winch drum  16  by engaging the planet gear shafts  20   a - c  in the openings  58   a - c . The openings  58   a - c  are of sufficient diameter for the coupling plate  54  to slide freely in an axial direction on the planet gear shafts  20   a - c.    
         [0025]    With reference to  FIG. 1 , as the coupling plate  54  slides toward the drive shaft  12 , the keyed hole  56  in the coupling plate  54  engages the pinion gear  40 , thereby causing the coupling plate  54  to rotate at the same speed as the drive shaft  12 . In this manner, the drive shaft  12  is directly coupled to the winch drum  16  through the coupling plate  54  and the planet gear shafts  20   a - c.    
         [0026]    It will be appreciated that high-speed operation of the winch  10  is achieved only when the gear reduction plunger  44  is retracted. In such a position, the plunger  44  does not engage any of the holes  46  in the ring gear  42 , and the ring gear is free to rotate along with winch drum  16 . If the plunger  44  is engaged in a hole  46  in the ring gear  42 , no rotation of the ring gear  42  or the drive shaft  12  may occur. This is due to the meshing of the planet gears  18   a - c  with the ring gear  42  and the coupling of the drive shaft  12  to the planet gear shafts  20   a - c  by means of the coupling plate  54 . In other words, when the plunger  44  is engaged with any of the holes  46  and the coupling plate  54  is engaged with the drive shaft  12 , the winch drum  16  is in a locked position. 
         [0027]    It will be appreciated that many mechanisms could be employed to move the coupling plate  54  in an axial direction to engage or disengage the drive shaft  12 .  FIG. 1  depicts the mechanism of a preferred embodiment. The coupling plate  54  is urged toward the pinion gear  40  by a plunger spring  60  which is in compression between a plunger  64  and a cam sleeve  62 . When the keyed hole  56  in the coupling plate  54  aligns with the pinion gear  40 , the spring  60  pushes the coupling plate  54  into engagement with the pinion gear  40 . A set of three coupling plate springs  66   a - c , which are in compression between the coupling plate  54  and the planet gears  18   a - c , push the coupling plate  54  against the plunger  64 . In this manner, the coupling plate  54  maintains continuous contact with the plunger  64 . The moduli of the coupling plate springs  66   a - c  are preferably less than that of the plunger spring  60  so that the coupling plate  54  will be forced into engagement with the pinion gear  40  when no other axial force is applied. 
         [0028]    The plunger spring  60  allows for misalignment between the pinion gear  40  and the keyed hole  56  by holding the coupling plate  54  against the pinion gear  40  until proper alignment is achieved through rotation of the pinion gear  40  or otherwise. If misalignment between the keyed hole  56  and pinion gear  40  occurs, the plunger spring  60  will hold the coupling plate  54  against the pinion gear  40  until there is proper alignment. In this manner, the plunger spring  60  helps compensate and correct for initial misalignment. 
         [0029]    To disengage the coupling plate  54  from the pinion gear  40 , the plunger  64  is pulled away from the coupling plate  54  by the rotation of a cam sleeve  136  to which the plunger  64  is attached. This compresses the plunger spring  60 , and the keyed hole  56  and pinion gear  40  disengage. This condition is illustrated in  FIG. 1 . In the preferred embodiment, the cam sleeve  62  is rotated by means of a direct drive handle  68 . 
         [0030]    A preferred embodiment of reduction gearing apparatus for coupling the motor  14  to the drive shaft  12  is depicted in  FIGS. 1 ,  3  and  4 . In this embodiment, the motor  14  drives a motor shaft  70  which is connected to a motor shaft pinion gear  72 . Although the pinion gear  72  is coaxial with the drive shaft  12 , the pinion gear  72  is not rotationally coupled to the shaft  12 . Rather, the pinion gear  72  rides on a pinion gear bearing  74  disposed between the gear  72  and the shaft  12 . 
         [0031]    The pinion gear  72  meshes with three planet gears  76   a - c  that are preferably spaced at 120 degree increments about the axis of the pinion gear  72 . The planet gears  76   a - c  are free to rotate about corresponding planet gear pins  78   a - c , the ends of which are secured to a drive shaft plate  80  and a planet gear support  88 . In the preferred embodiment of the invention, the drive shaft plate  80  is formed as an integral part of the drive shaft  12 . However, it will be appreciated that the plate  80  may be attached to the shaft  12  by various means, such as by welding. The planet gears  76   a - c  mesh with a ring gear  82  which is secured to the motor end housing  22  by screws  84 . A drum bearing  86  provides freedom of rotation between the drive shaft  12  and the drum  16 . As shown in  FIGS. 1 and 4 , a braking mechanism for the winch  10  includes brake plates  92  and brake stop pins  94   a ,  94   b  and  94   c.    
         [0032]    In the preferred embodiment of the invention, the gear reduction ratio from the motor shaft  70  to the drive shaft  12  is six-to-one (6-to-1). This provides a torque which is twice that of the winch design described in U.S. Pat. No. 5,842,684. 
         [0033]    In alternative embodiments of the invention, the motor shaft  70  may be coupled directly to the drive shaft  12 , such as using a shaft coupler. In this embodiment, the drive shaft  12  rotates at the same speed as the motor shaft  70 . 
         [0034]    According to the preferred embodiment of the invention, the winch operator may select from four different modes of winch operation depending upon the positions of the gear reduction selector handle  52  and the direct drive selector handle  68 . Low-speed winch operation is selected when the direct drive selector handle  68  is in the position shown in  FIG. 1  and the gear reduction selector handle  52  is rotated 180 degrees clockwise from the position shown in  FIG. 1 . High-speed winch operation is selected when the direct drive selector handle  68  is rotated 180 degrees clockwise from the position shown in  FIG. 1  and the gear reduction selector handle  52  is in the position shown in  FIG. 1 . Free-spool winch operation is selected when the direct drive selector handle  68  and the gear reduction selector handle  52  are both in the positions shown in  FIG. 1 . The winch is locked/braked (no dram rotation) when the direct drive selector handle  68  and the gear reduction selector handle  52  are both rotated 180 degrees clockwise from the positions shown in  FIG. 1 . 
         [0035]    In the preferred embodiment of the invention, the gear reduction plunger  44  and the direct drive plunger  64  are moved manually using the handles  52  and  68 , respectively. However, one skilled in the art will appreciate that the plungers  44  and  64  may also be actuated by solenoids powered by the battery of the vehicle on which the winch  10  is mounted. An example of a circuit for controlling solenoids in this application is described in U.S. Pat. No. 5,842,684. 
         [0036]    The foregoing description of preferred embodiments for this invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the invention and its practical application, and to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.