Patent Publication Number: US-8968140-B1

Title: Electronically actuated clutch for a planetary winch

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a winch. More particularly, the present invention relates to a solenoid activated clutch assembly for a planetary winch. 
     BACKGROUND OF THE INVENTION 
     Winches are used in numerous applications to lift or move heavy loads. Common applications include mounting them on tow trucks to pull a disabled vehicle onto the bed of the tow truck or lift one end of the disabled vehicle so that it can be hauled away. Another common application is to mount it on the front or rear end of a vehicle to assist in retrieving the vehicle where it is stuck. 
     In order to operate a winch it is necessary to be able to pull line off of the spool as well as be able retrieve the line with a load on it. Pulling line off of the spool or paying it out can be done by running the motor backwards such that the spool unwinds the line. While this method will work, it is time consuming, especially if a significant amount of line must be paid out. In these situations it is beneficial to disengage the spool from the drive mechanism. This allows the spool to rotate freely and for the line to be manually pulled off of the spool. Disengaging the spool is typically accomplished by a clutch mechanism. In the past, operation of the clutch mechanism is accomplished through direct manual control of the clutch. This requires the operator to be standing next to the winch and manually operate a gear lever. As can be imagined if the operator is loading a vehicle or moving another type of large load, standing next to the winch may not be the most convenient or safe location. 
     Various individuals have attempted to incorporate an electronically operated clutch with a winch having a planetary gear drive, also referred to as a planetary winch. This typically involved an electronic solenoid used to overcome a spring or other bias mechanism to move a plunger from an engaged position to a disengaged position (or vise-versa) relative to the ring gear of the planetary gear drive. 
     The standard solenoid used on these applications required a significant amount of power to move the plunger from one position to the other. Then once moved, the solenoid must remain energized to stay in the moved position and oppose the bias mechanism. This creates a significant drain on the electrical power source. This problem is compounded by the fact most of these winches are used on vehicle of some sort, such as a tow truck, off road vehicle, tractor or the like. This means the electrical power source is a battery with a limited service life. Thus the amount of time the winch can be used is greatly reduced by operation of the electronically actuated clutch. For this very reason electronically operated clutches are not commonly used. 
     In addition to depleting battery life, the current draw generates a tremendous amount of heat. If the solenoid remains energized for an extended amount of time the heat buildup will lead to failure of the solenoid. Even keeping the solenoid energized for a minute are two can have detrimental effects on the solenoid. 
     Others in the field have attempted to address this issue by using a solenoid that moves the plunger in one direction with a given polarity of power. The plunger then moves in the opposite direction when the opposite polarity of power is applied. However this is not optimal because of safety concerns. Namely, it is preferred from a safety standpoint to have plunger move to position of having the ring gear locked in place in the event of a power failure. This ensures the load on the winch remains in one place. This feature is not possible where the solenoid is dependent upon a certain polarity of power in order to move it to another position. 
     What is needed is an apparatus that allows a winch operator to engage and disengage a clutch without standing next to the winch. 
     Further what is needed is an electronically operated clutch for planetary gear that can operate on a minimum amount of power consumption. Thus avoiding depletion of the battery life and damage arising from the heat generated. 
     It is also important that the clutch design engages the clutch, that is, it locks the ring gear in place when there is a power failure. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention achieves these objectives by providing an electronically operated clutch for a planetary winch. The winch motor and electronically operated clutch can be operated via a remote. The clutch is engaged and disengaged by a solenoid. The solenoid is moved to a disengaged position by being energized by a first current level. Once in the disengaged position, the solenoid can be maintained in that position by a second current level. The second current level being less than the first current level. The clutch can be engaged by deenergizing the solenoid. Once deenergized, a bias means moves the solenoid plunger to an engaged position. 
     The present invention provides an electronically operated clutch for a planetary winch which is capable of maintaining the clutch in a disengaged position with minimal electric power consumption. Thus battery life and operational life are extended. Damage from heat buildup is also reduced 
     The present invention further provides an electronically operated clutch for a planetary winch which will engage the clutch in the event of a power failure or dead battery. This ensures the load held by the winch is not inadvertently dropped or released. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the invention will now be described in further detail. Other features, aspects, and advantages of the present invention will become better understood with regard to the following detailed description, appended claims, and accompanying drawings (which are not to scale) where: 
         FIG. 1  is a front view of a planetary winch of the present invention; 
         FIG. 2  is a right end view of a planetary winch of the present invention; 
         FIG. 3  is a cross sectional view of the winch of the present invention; and 
         FIG. 4  is a schematic showing the controls of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to the drawings wherein like reference characters indicate like or similar parts throughout,  FIGS. 1-3  illustrates a planetary winch  10 . It has a case  12  supporting a motor  14 , spool  16 , gear train  18  and clutch mechanism  20 . The motor  14  is typically electric or hydraulic. It is coupled to a first end of a shaft  22  via a coupler  24 . The shaft  22  extends through a hollow center  26  of the spool  16 . The gear train  18  is comprised of a sun gear  28 , a plurality of planet gears  30  and a ring gear  32 . The planet gears  30  are coupled to the spool  16  by a plurality of planet pins  34 . The planet gears  32  engage with the sun gear  28 . The planet gears  30  also engage the ring gear  32  which surrounds the outer perimeter of the orbit of the planetary gears  30 . In the preferred embodiment as shown the sun gear  28  is cut into a second end of the shaft  22 , however this could also be accomplished by a separate gear coupled to the second end of the shaft  22 . It is further possible to practice the present invention by having the motor  14  and gear train  18  located on the same side of spool  16 . 
     For purposes of explanation the condition of the clutch mechanism  20  being disengaged shall mean the spool  16  rotates freely. The condition of the clutch mechanism  20  being engaged shall mean the spool  16  is engaged with the motor  14  via the gear train  18 . 
     The clutch mechanism  20  is mounted to the case  12 . It is capable of selectively holding the ring gear  32  in place relative to the case  12  when in an engaged position and allowing the ring gear  32  to rotate relative to the case  12  when in a disengaged position. The clutch mechanism  20  is comprised of a solenoid  36 , bias means  38 , plunger  40  and one or more holes  42  in the ring gear  32 . The bias means  38  can take many forms including but not limited to a spring in either compression or tension. The holes  42  in the ring gear  32  are sized to receive the plunger  40  and located to pass by the plunger  40  as the ring gear  32  rotates around the planet gears  30 . 
     When the clutch mechanism  20  is disengaged, the solenoid  36  is energized. This overcomes the force of the bias means  38  and retracts the plunger  40  into the solenoid  36 . When the plunger  40  is in the retracted position the ring gear  32  is free to rotate relative to the case  12 . When the clutch mechanism  20  is engaged the solenoid  36  is not energized. The bias means  38  can then move the plunger  40  to an extended position where it or an attached linkage engages one of the holes  42  in the ring gear  32 . This locks the ring gear  32  and holds it in place relative to the case  12 . 
     The motor  14  can be operated to rotate in either direction. This causes the shaft  22  and sun gear  28  to rotate in the same direction as the motor  14 . As the sun gear  28  rotates, it engages with the planet gears  30  and causes them to rotate about the planet pins  34 . When the clutch mechanism  20  is disengaged, the rotation of the planet gears  30  about the planet pins  34  cause the ring gear  32  to rotate about the periphery of the planet gears  30 . This also means the ring gear  32  rotates freely relative to the case  12 . With the clutch mechanism  20  in the disengaged position the spool  16  can be rotated freely relative to the case  12 , regardless of the whether the motor  14  and gear train  16  are rotating. This allows the operator of the winch  10  to pay out or pull line off of the spool  16 . 
     When the clutch mechanism  20  is engaged the ring gear  32  is locked relative to the case  12 . Thus the rotation of the motor  14 , shaft  22 , sun gear  28  and planet gears  30  cause the planet gears  30  to orbit about the sun gear  28  as the planet gears  30  engage with the sun gear and the fixed ring gear  32 . The orbit of the planet gears  30  causes the spool  16  to rotate relative to the case  12 . 
     The control circuit  44  for the solenoid  36  provides a first current level  46  when first activated to retract the plunger  40 . This disengages the clutch mechanism  20 . Once the plunger  40  is moved to the retracted position, the control circuit  44  provides a second current level  48  which is less than the first current level  46 . The second current level  48  is used to maintain the plunger  40  in the retracted position. To engage the clutch mechanism  20 , the operator operates to control circuit  44  to deenergize the solenoid  36 . This allows the bias means  38  to move the plunger  40  to the extended position where it engages with a hole  42  in the ring gear  32 . The clutch mechanism  20  will also engaged in the event of a power failure. 
     The present invention can be used in various voltage systems. Because winches are typically found on vehicles, 12 volt and 24 volt systems are most likely to occur. In the preferred embodiment the first current level  46  is in the range of 20 amps to 100 amps, preferably about 70 amps and the second current level  48  is in the range of 0.5 amps to 5 amps, preferably about 0.88 amps. The length of time the first current level  46  is provided to the solenoid  36  may vary depending upon design requirements. In the preferred embodiment this is in a range of 250 milliseconds to 1 second, preferably 500 milliseconds. Ideally it would be no longer than the time necessary for the solenoid  36  to retract the plunger  40 . It is possible the clutch mechanism  20  would include a sensor  50  that senses when the clutch mechanism  20  has been disengaged and sends a signal to the control circuit  44 . Once the control circuit  44  receives a signal from the sensor  50 , the current level is changed to the second current level  48 . 
     The control circuit  44  and winch may be operated via a remote  52 . The remote  52  may be wired to the winch  10  or may be wireless. The remote  52  provides an interface with both the clutch mechanism  20  and motor  14  operation and may include other operational features. 
     The present invention as described above has the added advantage of locking the rotation of the spool  16  in the event of a power failure. This secures any load that might be on the winch  10 . The present invention could also be practiced where the bias means  38  of the clutch mechanism  20  holds the plunger  40  in the retracted position. However this embodiment would not inherently have the added safety feature of locking the rotation of the spool  16  in the event of a power failure. 
     The foregoing description details certain preferred embodiments of the present invention and describes the best mode contemplated. It will be appreciated, however, that changes may be made in the details of construction and the configuration of components without departing from the spirit and scope of the disclosure. Therefore, the description provided herein is to be considered exemplary, rather than limiting, and the true scope of the invention is that defined by the following claims and the full range of equivalency to which each element thereof is entitled.