Abstract:
Apparatus for actuating a trailer jack having a carrier shaft or drive shaft with an exposed end portion includes an adapter that is connectable to the end portion of the carrier shaft or drive shaft in driving relationship and a drive member that is connectable to the adapter in driving relationship. A driving member such as a drill chuck of an electric drill can be connected to the drive member. The connection between the adapter and the drive member preferably is made by specially shaped members that cannot easily be engaged or operated by commonly available tools. The apparatus can be provided on an OEM basis or it can be provided as an aftermarket modification to existing jacks. A crank can be provided to permit manual actuation of the jack in the event that an electric drill is not available or is inoperable.

Description:
REFERENCE TO PROVISIONAL APPLICATION 
       [0001]    The present application claims priority to U.S. provisional application Ser. No. 61/926,680, entitled Trailer Jack and Method of Actuation, filed Jan. 13, 2014 by Dion Magestro, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates generally to jacks and, more specifically, to a device particularly suited to actuate a trailer jack. Although the present invention largely is described with reference to a “trailer jack,” it is to be understood that the device and method of the present invention are not limited to use with trailer jacks and, indeed, they can be used with other types of jacks or other equipment or for other purposes as those skilled in the art will appreciate. Accordingly, use of the phrase “trailer jack” or “jack” herein is for convenience of description and is not to be construed as limiting the operation or use of the invention to only trailer jacks. 
         [0004]    2. Description of the Prior Art 
         [0005]    Trailers are used to haul heavy and/or large objects or materials such as boats, livestock, etc. behind vehicles. Typically the tongue of the trailer is connected to or disconnected from a trailer hitch while the trailer is in an unloaded state so as to minimize the difficulty in raising and lowering the tongue. Nevertheless, a large, unloaded trailer can be sufficiently heavy that it is necessary to use a jack to raise and lower the tongue. Any such difficulty in raising or lowering the tongue is increased if the trailer were to be loaded with cargo at the time it is connected to or disconnected from the trailer hitch. Regardless of the loaded or unloaded condition of the trailer, it often is desirable to use a jack to maintain the trailer in a generally horizontal position while it is disconnected from a vehicle. 
         [0006]    Trailer jacks often are permanently attached to trailer tongues and actuated manually by means of a crank. The jack with its attached crank often can be folded to a stowed position so that it is unobtrusive during travel or other trailer operations. Trailer jacks of the type described are commercially available from a number of manufacturers, including Cequent Performance Products, 47912 Halyard Drive, Suite 100, Plymouth, Mich. 48170 (“BULLDOG” trailer jacks) and Shelby Industries, LLC, 175 McDaniel Road, Shelbyville, Ky. 40065. 
         [0007]    Most of the trailer jacks in question have a load plate that is connected to a housing. An internal tube having a base or caster wheel is disposed within the housing for telescoping movement relative to the housing. A rotatable, threaded carrier shaft interconnects the housing and the internal tube. The load plate can be connected to the tongue of a trailer or other object to be lifted. The direction of movement of the load plate relative to the base or caster wheel depends on the direction in which the carrier shaft is rotated. 
         [0008]    A carrier bevel gear sometimes is disposed at one end of the carrier shaft. A drive bevel gear is carried by a drive shaft disposed at right angles to the longitudinal axis of the carrier shaft. The teeth of the drive and carrier bevel gears intersect with each other. By this construction, rotation of the drive shaft causes the carrier shaft to rotate thereby moving the housing, and hence the load plate, relative to the base or caster wheel. 
         [0009]    Typically, the carrier shaft is rotated by a crank that extends through the center of the drive shaft. Alternatively, the bevel gears and drive shaft can be dispensed with and the crank can be connected directly to an exposed end of the carrier shaft. In both cases, the crank often can be removed for storage or repositioned to make the assembly more compact. 
         [0010]    Over the years, a number of improvements have been made to trailer jacks of the type described. Most notably, the introduction of a power source to operate jacks has significantly improved functionality and ease of use. Although there are a variety of types of trailer jacks on the market, and although some of them are or can be power-operated, a problem still exists concerning the ease of use, actuation speed and cost of the jacks. 
         [0011]    Prior efforts have been made to reduce the difficulty of actuating jacks. For example, U.S. Publication No. 2012/0037862 discloses an in-line jack that includes a body, an extendable shaft, drive mechanics and a motor. A planetary gear system also can be provided to connect the motor to a drive shaft. Unfortunately, the components are aligned axially which has the potential to increase the space required for proper jack operation. 
         [0012]    Another example of a powered jack is shown in U.S. Publication No. 2007/0256526 in which a portable, battery-operated drill is used to actuate a jack by means of various adaptors or sockets that provide a connection between the drill and the jack. Other examples of similar devices include U.S. Pat. No. 6,910,677; U.S. Pat. No. 6,237,894; U.S. Pat. No. 6,039,126; U.S. Pat. No. 5,897,121, U.S. Pat. No. 5,876,526, U.S. Pat. No. 5,876,526; U.S. Pat. No. 5,771,516; U.S. Pat. No. 1,861,326; U.S. Pat. No. 1,465,057; and United Kingdom Patent No. 2210303-A. 
         [0013]    A problem with the referenced devices is that they generally are, either alone or in various combinations, not easily used, very cumbersome, quite expensive or of limited effectiveness. Another problem with prior devices is that their use is not limited to authorized persons, i.e., even if an adapter or socket is provided, it can be operated by unauthorized persons. 
         [0014]    Desirably, a device would be available that would enable an authorized user to conveniently operate a trailer jack with a common power source such as a battery-operated electric drill, while preventing operation by unauthorized persons. 
       SUMMARY OF THE INVENTION 
       [0015]    The present invention provides a new and improved technique for operating a trailer jack that significantly reduces the time and effort required to operate the trailer jack. The invention can be sold as original equipment manufacture (“OEM”) or as part of a trailer jack “kit,” or aftermarket add-on, to modify an existing jack. The present invention is usable with many types of trailer jacks, including those with cranks that connect directly to an end of a carrier shaft and those with cranks that connect to a gearing mechanism such as bevel gears and a drive shaft. 
         [0016]    Apparatus according to the invention includes an adapter that is connectable to an end portion of a carrier shaft or drive shaft in driving relationship and a drive member that is connectable to the adapter in driving relationship. A driving member such as a drill chuck of an electric drill can be connected to the drive member. In order to restrict actuation of the jack only to authorized users, the connection between the adapter and the drive member is made by specially shaped members that cannot easily be engaged or operated by commonly available tools. The apparatus can be provided on an OEM basis or it can be provided as an aftermarket modification to existing jacks. 
         [0017]    In an aftermarket embodiment, the factory-provided crank is removed, leaving the end of the carrier shaft or drive shaft exposed. For convenience, the exposed end of the carrier shaft or drive shaft will be referred to as the “drive end.” An adapter having first and second ends is provided. The first end is a female end that is fitted over the drive end and secured to the first end, preferably by a torque-limiting member such as a shear pin (or “tension pin”), barrel bolt, or similar member. The tension pin extends through aligned openings in the first end of the adapter and the drive end. The tension pin preferably is intended to retain the adapter in place at the end of the drive end at all times. Alternatively, the tension pin could be sized such that it would be removable or relatively loosely fitted into place; in that event, it would retain the adapter only during times of jack actuation and would be removed, along with the adapter, at other times. The second end of the adapter preferably is a male end that is in the form of a security shape in order to prevent unauthorized operation of the jack. Alternatively, the second end of the adapter can be provided in the form of a square drive or similar shape such as a hex end. 
         [0018]    A drive member having first and second ends is included as part of the invention. In one embodiment, the first end of the drive member is a socket that is configured to fit over a substantial portion of the adapter. If the tension pin is removable, the first end includes skirt walls that cover the tension pin and prevent its removal during jack operations. The first end also includes a drive portion disposed within the socket that engages the second end of the adapter in a driving relationship. In another embodiment, the first end of the drive member defines a socket that includes a drive portion that engages the second end of the adapter in a driving relationship. In each embodiment of the drive member, the second end of the drive member is configured to be engaged by the chuck of a typical electric drill motor in a driving relationship. It is expected that the second end of the socket will be hexagonal in shape or will be provided with axially extending channels in order to be securely grasped by the chuck. 
         [0019]    The invention can be provided in different sizes to fit jacks of all types, including jacks suitable for use with semi-trailers. In addition, the adapter can be provided in modified form. For example, the second end of the adapter can be in the form of socket opening rather than a male drive end. The socket opening could be of a size and shape suitable for receiving the square drive end of a typical ratchet handle as are commonly provided in toolkits. If this type of adapter is used, the previously described socket-type drive member will not be needed, although the crank will have to include a male end (protrusion) suitable for engaging and rotating the adapter. In yet another variation, the second end of the adapter could be in the form of a socket opening having a security shape, and the previously described drive member could include a male end having a security shape that mates with the security shape of the adapter. 
         [0020]    It is expected that the crank will include a handle at one end and a drive member such as a keyed opening or protrusion at the other end. The keyed opening or protrusion is of a size and shape to engage the second end of the adapter in a driving relationship. Accordingly, the user will be able to actuate the jack in the event of a problem such as the drill batteries being discharged or the socket being misplaced or otherwise unavailable. 
         [0021]    The invention greatly simplifies the task of raising and lowering a trailer jack, and significantly reduces the time and effort required to conduct jack operations. Not only can the invention be provided as part of new construction or as an aftermarket kit that can be used to retrofit existing jacks, but the actuator (typically a battery-operated electric drill motor) is available to many users and commonly is carried in a truck or other towing vehicle. When supplied in the preferred embodiment, the invention will make it difficult for unauthorized persons to operate the jack, thereby serving as an impediment to theft of the object that is being supported by the jack. The invention is inexpensive and practical, and avoids the drawbacks associated with prior devices of a similar nature. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The foregoing and other features and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates upon reading the following description with reference to the accompanying drawings, in which: 
           [0023]      FIG. 1  is a perspective view of a jack according to the invention, showing various actuating components aligned with a longitudinal axis of a carrier shaft; 
           [0024]      FIG. 2  is an enlarged side elevational view, partly in section, of a portion of the invention of  FIG. 1 ; 
           [0025]      FIG. 3  is a view similar to  FIG. 2  showing an alternate embodiment of the invention in which actuating components are disposed at a right angle to the longitudinal axis of the carrier shaft; 
           [0026]      FIG. 4  is a view similar to  FIG. 3  showing an alternate form of actuating components similar to those shown in  FIGS. 1 and 2 ; 
           [0027]      FIG. 5  is a perspective view of apparatus according to the invention in which an adapter has a “security configuration” and a drive member includes a socket having a configuration that mates with the security configuration of the adapter; 
           [0028]      FIG. 6  is a view similar to  FIG. 3  showing a particular form of security configuration and drive member; 
           [0029]      FIG. 7  is a view similar to  FIG. 5  showing a crank having a drive member according to the invention that can be used to manually operate a trailer jack; and 
           [0030]      FIG. 8  is a view similar to  FIG. 5  in which a drive member has a “security configuration” and an adapter includes a socket having a size and shape that mates with the security configuration of the drive member. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0031]    Referring to  FIG. 1 , apparatus according to the invention is indicated generally by the reference numeral  10 . The apparatus  10  includes a jack having an elongate outer housing  12  having first and second ends  14 ,  16 . A base plate  18  is attached to an inner housing (not shown) that projects out of the first end  14 . The housing  12  includes an elongate support rib  20 . A load plate  22  is connected as by welding to the outer housing  12  for movement therein. If desired, the base plate  18  could be replaced by a caster wheel. 
         [0032]    A carrier shaft  24  is disposed within the outer housing  12 . The carrier shaft  24  has a longitudinal axis  25  coincident with that of the outer housing  12 . The carrier shaft  24  has external threads (not shown) that are engaged by the inner housing. Accordingly, when the carrier shaft  24  is rotated about its longitudinal axis  25 , the inner housing and the attached base plate  18  or caster wheel will be moved telescopically relative to the outer housing  12 . The direction of movement of the load plate  22  relative to the base plate  18  or the caster wheel will depend on the direction in which the carrier shaft  24  is rotated. 
         [0033]    Referring also to  FIG. 2 , the carrier shaft  24  has an exposed end  26 . An opening  28  is formed in the exposed end  26 . The opening  28  preferably is cylindrical although other shapes are possible. The opening  28  is disposed at a right angle to the longitudinal axis  25  of the carrier shaft  24 . 
         [0034]    The jack  10  includes an adapter  30 . The adapter  30  has a first end  32 , a second end  34 , and a shaft or neck  36  that connects the first and second ends  32 ,  34 . The first end  32  has a longitudinally extending opening (not shown) that is adapted to fit over the exposed end  26  of the carrier shaft  24 . The first end  32  has a transverse opening  33  of the same general size and shape as that of the opening  28  in the exposed end  26  of the carrier shaft  24 . A torque-limiting member in the form of a shear pin (“tension pin”) or barrel bolt  38 , is provided. The tension pin  38  is a generally cylindrical member that fits into the openings  28 ,  33  when they are aligned with each other. The tension pin  38  preferably is press-fitted into the openings  28 ,  33  so that the adapter  30  cannot be removed. Alternatively, as will be described in more detail, the tension pin  38  can be removable or relatively loosely fitted into the openings  28 ,  33 . The second end  34  preferably is in the form of a unique security shape, although common shapes such as a square end or hex end conceivably could be employed. 
         [0035]    The apparatus  10  includes a drive member  40 . The drive member  40  has a first end  42  and a second end  44 . The first end  42  is in the form of a hollow socket and is of the same size and shape as the external configuration of the adapter  30 . The first end  42  is defined by a relatively thin sidewall  46  and includes a drive receptacle  48  at the upper end thereof that is adapted to receive the second end  34  of the adapter  30  in driving relationship. The second end  44  is in the form of a drive member such as a hex end, an end with axially extending channels, or a square end. A hex end or channeled end is preferred. 
         [0036]    An electric drill  50  is usable as part of the invention  10 . The drill  50  has a motor  52 , a chuck  54 , a handle  56  with a trigger, and a removable, rechargeable battery pack  58 . The drill  50  can be of any well known type, and can be powered by house current rather than a battery pack  58 , if desired, and may include other features such as a torque limiter, a reversing motor, etc. 
         [0037]    The apparatus  10  includes a crank  60 . The crank  60  has an elongate shaft  62 , a handle  64  at one end of the shaft  62 , and a keyed opening  66  at the other end of the shaft  62 . The keyed opening  66  is of a size and shape to fit over, and engage, the drive end  34  of the adapter  30 . 
         [0038]    Referring now to  FIG. 3 , a second embodiment of the invention is indicated by the reference numeral  70 . The embodiment  70  shares certain features of the embodiment  10 , and like reference numerals will be used to indicate the same or similar features of the two embodiments. 
         [0039]    A housing  72  includes an opening  74  that extends through the side thereof adjacent the second end  16 . Drive gears (not shown) are disposed within the housing  72  adjacent the second end  16 . A drive shaft  76  having first and second ends  78 ,  80  is provided. The drive shaft  76  is similar to conventionally supplied drive shafts. The first end  78  extends through the opening  74  and engages the drive gears in driving relationship. The second end  80  is in the form of a “security configuration” that is not engageable with commonly sized sockets, wrenches, and other tools. 
         [0040]    The embodiment  70  also includes a socket  82  that is similar to the socket  40  and a crank  84  that is similar to the crank  60 . The socket  82  includes a hollow, first end  86  and a second end  44  that defines a drive member. The first end  86  is of the same size and shape as the second end  80  of the drive shaft  76  and therefore engages the second end  80  in a driving relationship. The second end  44  preferably is a hex end that can be engaged by the chuck  54 . The crank  84 , like the crank  60 , has a handle  64  and a keyed opening  66 . The opening  66  is sized to engage the second end  44  in driving relationship. 
         [0041]    Referring now to  FIG. 4 , a third embodiment of the invention is indicated by the reference numeral  90 . The embodiment  90  shares certain features of the embodiments  10 ,  70  and like reference numerals will be used to indicate the same or similar features of the various embodiments. 
         [0042]    A housing  72  includes an opening  74  that extends through the side thereof adjacent the second end  16 . Drive gears (not shown) are disposed within the housing  72  adjacent the second end  16 . A drive shaft  92  having a first end (not shown) and a second, exposed end  94  is provided. The first end of the drive shaft  92  extends through the opening  74  and engages the drive gears in driving relationship. The second end  94  includes an opening  28 . 
         [0043]    The embodiment  90  includes an adapter  96  similar to the adapter  30 , a socket  98  similar to the socket  40 , and a crank  60  (not shown in  FIG. 4 ). As with the embodiment  10 , a tension pin or barrel bolt (not shown) is used to connect the adapter  96  to the exposed second end  94  via aligned openings  28 ,  33 . 
         [0044]    Referring now to  FIG. 5 , another embodiment of the invention is indicated by the reference numeral  110 . The embodiment  110  shares certain features of the embodiment  10 , and like reference numerals will be used to indicate the same or similar features of the two embodiments. 
         [0045]    The embodiment  110  includes an adapter  112 . The adapter  112  has a first end  114  that defines a socket and a second end  116  in the form of a “security configuration.” The first end  114  has a longitudinally extending opening (not shown) that is adapted to fit over the exposed end  26  of the carrier shaft  24 . The first end  114  has a transverse opening of the same general size and shape as that of the opening  28  in the exposed end  26  of the carrier shaft  24 . A torque-limiting member in the form of a shear pin (“tension pin”) or bolt  118  is provided. The bolt  118  is a generally cylindrical member that fits into the opening  28  and the openings in the first end  114  when they are aligned with each other. The bolt is retained in place by a nut  120 . The second end  116  has a cylindrical central portion  122  from which laterally extending, rounded wings  124  extend. A transverse opening  126  extends through the central portion  122  at approximately its mid-point. 
         [0046]    The embodiment  110  includes a drive member  130 . The drive member  130  has a first end  132  and a second end  134 . The first end  132  includes a hollow socket  133  that is of the same size and shape as the external configuration of the second end  116  of adapter  112 . The second end  134  is in the form of a drive member having axially extending channels  136  that are particularly adapted to be engaged by the chuck  54  of the drill  50 . 
         [0047]    Referring now to  FIG. 6 , another embodiment of the invention is indicated by the reference numeral  140 . The embodiment  140  shares certain features of the embodiments  70 ,  90 , and  110 , and like reference numerals will be used to indicate the same or similar features of the various embodiments. 
         [0048]    A housing  72  includes an opening  74  that extends through the side thereof adjacent the second end  16 . Drive gears (not shown) are disposed within the housing  72  adjacent the second end  16 . A drive shaft  76  having first and second ends  78 ,  142  is provided. The drive shaft  76  is similar to conventionally supplied drive shafts. The first end  78  extends through the opening  74  and engages the drive gears in driving relationship. The second end  142  is in the form of a “security configuration” substantially similar to that of the second end  116  of adapter  112 . 
         [0049]    The embodiment  140  also includes a drive member  144 . The drive member  144  is substantially similar to the drive member  130 . 
         [0050]    Referring now to  FIG. 7 , another embodiment of the invention is indicated by the reference numeral  150 . The embodiment  150  shares certain features of the embodiments  10  and  110 , and like reference numerals will be used to indicate the same or similar features of the various embodiments. 
         [0051]    The embodiment  150  includes an adapter  152 . The adapter  152  is substantially identical to the adapter  112 . The embodiment  150  includes a crank  160 . The crank  160  has an elongate shaft  162 , a handle  164  at one end of the shaft  162 , and a drive member  166  at the other end of the shaft  162 . The drive member  166  is of a size and shape to fit over, and engage, the second end  116  of the adapter  152 . The drive member  166  includes an opening  168  that is adapted to receive a bolt such as the bolt  118 , which can be retained in place by a nut  120 . 
         [0052]    Referring now to  FIG. 8 , another embodiment of the invention is indicated by the reference numeral  170 . The embodiment  170  is similar to the embodiment  110  except that the second end  116  extends from the first end  132  of the drive member  130 , while the opening  133  is formed in the exposed end of the adapter  112 . Essentially, the embodiments  110 ,  170  have a reversal of connected drive elements. In this embodiment  170 , aligned, opposed openings (not shown) can be provided for the adapter  112  in order to permit a bolt and nut (not shown) to engage the opening  126 , if desired, and thereby retain the drive member  130  in place. Similarly, a drive member similar to the drive member  130  could be attached to a crank similar to the crank  160  and held in place by the bolt and nut. 
         [0053]    Most of the components of the embodiments  10 ,  70 ,  90 ,  110 ,  140 ,  150 ,  170  are made of commonly available materials such as stainless steel or chrome-plated steel. Typical dimensions for certain of the components are as follows. It is to be understood that these dimensions are approximations and variations can be made without affecting the efficacy of the invention. 
         [0054]    exposed end  26 : ½ inch diameter 
         [0055]    opening  28 : ⅜ inch diameter 
         [0056]    adapter  30 : 2¾ inches overall length, ½ inch I.D. of first end  32 , ⅜ inch diameter of opening  33 , 5/16 diameter of shaft  36 , ¾ inch length of second end  34   
         [0057]    socket  40 : 3¾ inches overall length, ⅛ inch thick sidewall  46 , ¾ inch length of second end  44  with 5/16 inch hex end 
         [0058]    cranks  60 ,  84 : 8 inches long 
         [0059]    opening  74 : ½ inch diameter 
         [0060]    drive shaft  76 : ½ inch diameter, 5 inches long 
         [0061]    socket  82 : 3 inches overall length 
         [0062]    drive shaft  92 : ½ inch diameter (one inch diameter for heavy duty applications) 
         [0063]    opening  96 : ⅜ inch diameter (½ inch diameter for heavy duty applications) 
         [0064]    tension pin for embodiment  90 : sized to fit opening  96 . 
       Operation 
       [0065]    In embodiment  10 , the first end  32  of the adapter  30  is fitted over the exposed second end  26  of the carrier shaft  24 , the openings  28 ,  33  are aligned, and the tension pin  38  is press-fitted or otherwise non-removably held in place within the aligned openings  28 ,  33 . By this construction, the adapter  30  is non-removably mounted to the exposed end  26 . If a relatively loosely fit tension pin  38  is provided, the socket  40  is placed over the adapter  30  such that the tension pin  38  is retained in place by being covered by the lower end of the sidewall  46 . Also, if the tension pin  38  is removable, the adapter  30  can be removed and taken from place to place or used on other trailer jacks having a similar construction. Such a feature could be useful, for example, in conjunction with semi-trailers that pass temporarily through many different places and that may be under the control of different people. 
         [0066]    If the adapter  30  is non-removable, the security shape of the second end  34  will prevent or tend to prevent unauthorized operation of the jack. If the adapter  30  is removable, the exposed end  26  will be accessible when the jack is not being operated. It is expected that the exposed end  26  will not be easily grasped which will serve as a deterrent to unauthorized jack operation. 
         [0067]    So long as the adapter  30  is held in place by the tension pin  38 , the first end  42  of the socket  40  can engage the second end  34  of the adapter  30  and thereby establish a driving relationship with the carrier shaft  24 . The chuck  54  can be affixed to the second end  44  of the socket  40 . Thereafter, the motor  52  can be operated so as to rotate the carrier shaft  24  in a desired direction and extend or retract the base plate  18 . 
         [0068]    In embodiment  70 , the socket  82  is fitted over the second end  80  of the drive shaft  76  so that the socket  82  and the drive shaft  76  engage each other in a driving relationship. The chuck  54  is affixed to the second end  44  of the socket  82 . Thereafter, the motor  52  can be operated so as to rotate the carrier shaft  24  in a desired direction and thereby extend or retract the base plate  18 . The embodiment  90  is assembled and operated in the same manner as the embodiment  10 . In all embodiments, the cranks  60 ,  84  can be used to engage the drive ends  34 ,  44 , or  80 , as the case may be, in order to operate the jack  10  in the event that the drill  50  is not available or is inoperative. 
         [0069]    Embodiments  110 ,  140 ,  150 ,  170  essentially operate in the same manner as embodiments  10 ,  70 ,  90 . In each instance, an adapter is secured to the end portion of a carrier shaft or drive shaft, a drive member is provided that can engage the adapter in a driving relationship, and a power source such as an electric drill or a crank can be connected to the drive member so as to rotate the drive member, adapter and carrier shaft or drive shaft. In these embodiments a “security configuration” has been disclosed in the form of an elongate center portion  122  from which flanges  124  laterally project. It will be appreciated that many other forms of security configurations could be provided, if desired. 
         [0070]    As will be apparent from the foregoing description, the invention can significantly reduce the time and effort required to operate a trailer jack. It is believed that the invention can enable a user to operate the jack in only about 10% of the time and with far less effort than required to operate the jack manually. The invention can be provided as part of new construction or as an aftermarket kit that can be used to retrofit existing jacks. The invention is particularly effective because battery-operated electric drills are available to many users and commonly are carried in a truck or other towing vehicle. When supplied in the preferred embodiment, the invention will make it difficult for unauthorized persons to operate the jack, thereby serving as an impediment to theft of the object that is being supported by the jack. The invention is inexpensive and practical, and avoids the drawbacks associated with prior devices of a similar nature. 
         [0071]    Although the invention has been described in detail with reference to particular examples and embodiments, the examples and embodiments contained herein are merely illustrative and are not an exhaustive list. Variations and modifications of the present invention will readily occur to those skilled in the art. The present invention includes all such modifications and equivalents.