Abstract:
A slidable adjustable jacking device where the numbers of rotations of a hand crank on a jacking device may be greatly reduced by using a slidable screwjack inner member to re-position a load-carrying member. New in the art is the use of a slidable screwjack inner member and an affixed bar within a tubular outer member and an affixed passageway. This invention re-positions a slidable screwjack inner member to a location and then pins the member such that the member is fixed relative to a trailer. The device is useful for raising or lowering the tongue of a trailer.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     FEDERALLY SPONSORED RESEARCH 
     Not Applicable 
     SEQUENCE LISTING OR-PROGRAM 
     Not applicable 
     BACKGROUND 
     1. Field of Invention 
     This present invention relates to implements or apparatus for applying pushing or pulling force, specifically to a slidable adjustable screwjack inner member for a lifting jack. Particularly, this present invention relates to a slidable adjustable jacking device mounted on a tongue of a trailer. More particularly, this invention improves the ability to reduce the number of times a hand crank must be rotated to extend a load-carrying member. This device allows a screwjack inner member to be slid inside a tubular outer member and then pinned in a fixed position. 
     2. Prior Art 
     There are times when a lifting jack must have a hand crank rotated many times to extend a load-carrying member so that the member or leg makes contact with the ground to transfer weight. Likewise, upon retracting certain lifting jacks, a hand crank of the jackscrew in the lifting jack must be rotated many times. There have been various attempts to extend or retract the load-carrying member of the lifting jack so that the amount of time and the number of times the hand crank has to be rotated is reduced. 
     In 1910, Erastus Coddington was awarded U.S. Pat. No. 964,394. This historical patent teaches a lifting jack with a slideable sleeve over a stem. A stem is adjustable and supported on a standard. A sleeve rotates in the stem. There are recesses in the sleeve to allow the stem to be adjustable according to vertical slots. The lifting jack height can be adjusted using slots. However, this device is limited to supporting the weight that rests on these small stems. 
     Israel Gross&#39;s U.S. Pat. No. 2,852,229 teaches lifting equipment for jack operations. This invention has a base and a vertically erect post. The post is provided, at spaced intervals, with diametrically extended perforations to permit adjustment of the position of the adjustable header. The adjustable header includes a tubular portion, which surrounds the post and connects with the header. The advantage of this construction is the considerable height obtainable in this assembly and heavy loads can be lifted by the application of a relatively small force at the jack. The disadvantage of this construction is that it is complicated because it uses a regular lifting jack and additional pieces. The pieces are not integral to the lifting jack and the setup is also complicated. 
     U.S. Pat. No. 3,275,298, Demountable Containers Provided With Jack Legs for Raising or Lowering the Same, was issued to Albert Hand in 1966. Hand relates to heavy-duty devices for raising, supporting and lowering heavy, bulky bodies, which are required to be moved between relatively low and relatively high elevations and to be supported at levels in between. The jack leg includes a reaction base that is vertically adjustable on the standard between a station adjacent to the foot and at least one station spaced above. To permit the adjustment there are holes in the standard. The holes are registerable (able to be aligned) between the standard and the reaction base using a pin. However, this device does not use the jack as the course alignment but rather a standard off to the side. The force must be channeled through a reaction base, creating a weak link in the transfer of the force vector. 
     In 1969, Burdette Douglass was awarded U.S. Pat. No. 3,595,527, Quickly Retractable and Extensible Jack Construction, which teaches a jack body that adjusts the load-carrying member that is slidable in the jack body. The Douglass patent uses L-shaped slots in the sleeve and radial projections on the jack body to elongate the jack and provide for rough adjustment in the length of the jack. After the rough adjustment is made, a screw arrangement is used to make fine jacking adjustments. But these L-shaped sleeves can only support so much weight. This weakness is similar to Coddington 964,394 because the much force must be transferred to relatively small ‘dog ears’ or stems. 
     Leroy Scott, in 1978, was granted a patent for “Heavy Duty Lifting Devices” in U.S. Pat. No. 4,068,826. Scott&#39;s invention teaches a plurality of engagement positions for the hydraulic piston rod to permit a greater extension of the load-carrying sleeve with respect to the base of the jack. This invention does not, however, uncomplicated the process of raising or lowering items. 
     In 1979, Francis Linton et al. were issued U.S. Pat. No. 4,176,824, Lifting Apparatus. This invention teaches a fixture made of two side-by-side plates and two bails fastened to a vehicle. The side-by-side plates are provided with two sets of aligned apertures through which pins may be inserted. This device is limited in nature because the bail fasteners are a point of weakness with regard to transferring forces from the thing being lifted to the area where the lifting apparatus transfers its weight. 
     U.S. Pat. No. 4,238,113, Jacking Device, was issued to Vernon Adams in 1980. Adams teaches a detached slideable column with a plurality of longitudinally spaced holes extending transversely through the column to provide for the rough adjustment of the column. But this device is comprised of an adjustable column that is not integral to the upright vertical housing and places strain on a rough adjusting column. 
     Dale McMahan&#39;s U.S. Pat. No. 4,842,252, Rapidly Extendable Jack, was issued in 1989. This invention teaches a rapidly expandable jack and a course adjustment mechanism using a pin and a hole arrangement with the pin protruding from the outer sleeve through the inner sleeve. But the pin that the invention uses will only support the weight that rest on a small portion of a pin. 
     Jerry Pittman&#39;s U.S. Pat. No. 5,174,550 is a complicated device that teaches a quick release and quick retract jack that features an outer wall of a tubular member that is deformed inwardly forming detents equally spaced along a significant portion of the length of the outer wall. These detents form spaced projections, which extend inwardly from the inner wall into the bore of the tubular member. The detents allow for positioning of the sleeve. 
     An Internet publication teaches using a “Hi-Lift’ jack that uses pins to adjust the length of travel of a jacking device. But this device does not have a slidable sleeve to reduce the number of rotations. 
     An Internet publication teaches a square tube jack, but this jack is not slidable out either end of the outer tube. Shelby Industries makes a “8000 # Top Wind Sq Tube Jack, Weld-On, Drop Leg, Black,” but the device, if welded onto a trailer would require an operator to reach below the trailer to remove or insert a pin to fix the leg length. 
     SUMMARY 
     The present invention is directed to a Class 254, Implements or Apparatus for Applying Pushing or Pulling Force, Subclass 134, Adjustable. 
     The present invention is an implement for applying a pushing force comprising a slidable adjustable screwjack inner member which reduces the number of rotations required by a hand crank to extend a load-carrying member. 
     The principles of the invention will be further discussed with reference to the drawings wherein preferred embodiments are shown. The specifics illustrated in the drawings are intended to exemplify, rather than limit, aspects of the invention as defined in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings. 
         FIG. 1  shows a perspective of the device manufactured using round dimensions for a tubular outer member, including an affixed passageway, complementary passageway holes in the sides of a passageway, and a flange surrounding the tubular outer member and the affixed passageway. 
         FIG. 2  shows a perspective of the device, including a tubular outer member and a passageway, a screwjack inner member with a bar that is affixed to a screwjack inner member and that slides in a passageway, a load-carrying member on the bottom of the invention, a hand crank on the top of the invention, complementary passageway holes, bar holes, and a pin. 
         FIG. 3  shows a top view of the device, including a pin in a pinned arrangement, flange mounting openings and a hand crank. 
         FIG. 4  shows a side view of a slidable, adjustable jacking device with a load-carrying member in a raised position, including a tubular outer member, a screwjack inner member, a load-carrying member, a hand-crank, and a foot; as the device would be situated on a trailer. 
         FIG. 5  shows a perspective of the device manufactured using square or rectangular dimensions for a tubular outer member, including an affixed passageway, complementary passageway holes in the sides of a passageway, and a flange surrounding a tubular outer member and an affixed passageway. 
     
    
    
     REFERENCE NUMERALS 
     
         
           10  Slidable adjustable jacking device 
           11  Tubular outer member 
           12  Passageway 
           13  Complementary passageway holes 
           14  Flange 
           15  Flange mounting opening 
           16  Bar hole 
           17  Hand crank 
           18  Pin 
           20  Screwjack inner member 
           21  Bar 
           22  Load-carrying member 
           23  Trailer 
           24  Foot 
           25  Jackscrew 
       
    
     DESCRIPTION 
       FIG. 1  is a view of a tubular outer member of a slidable, adjustable jacking device  10 . The slidable adjustable jacking device  10  is tubular in nature, consisting of a round tubular outer member  11  with a passageway  12  attached axially to a wall of a round tubular outer member  11 . The passageway  12  is rectangular in shape and has three walls. There are two parallel walls and an exterior wall. A flange  14  is welded to the exterior of a tubular outer member  11  and surrounds the round tubular outer member  11  and the passageway  12 . If it is preferred, tubular outer member  11  and the passageway  12  may be forged as a single unit. A flange  14  is triangular in shape. There are flange mounting openings  15  in the flange  14  so it can be bolted to a trailer  23 . There are three flange mounting openings  15 ; one flange mounting opening  15  in each corner of the flange  14 . The area formed by the round tubular outer member  11  and the passageway  12  is designed to accept a screwjack inner member  20 . There are complementary passageway holes  13  in sidewalls of the passageway  12  for accepting a pin  18 . 
       FIG. 5  is similar in nature to  FIG. 1 , except that it represents a rectangular version of the slidable adjustable jacking device  10 . The flange  14  on a square or rectangular version of a slidable adjustable jacking device  10  is square or rectangular and includes an additional flange mounting opening  15 ; one flange mounting opening in each corner of the flange  14 . 
       FIG. 2  represents a slidable adjustable jacking device  10 . The figure depicts a tubular outer member  11  and a passageway  12  with a screwjack inner member  20  and a bar  21  installed inside the tubular outer member  11  and the passageway  12 . A screwjack inner member  20  has a bar  21  affixed axially on its outside surface. A bar  21  may be welded axially to the screwjack inner member  20 . As an alternative, a single piece may be forged as a solid unit made up of a combination of bar  21  and screwjack inner member  20 . The bar  21  has bar holes  16  drilled transversely at equally distant locations along the length of the bar  21 . These bar holes  16  are the same distance apart as the complementary passageway holes  13  so that when the complementary passageway holes  13  and the bar holes  16  are registered together in alignment, a pin  18  can be inserted through and a slidable adjusting jacking device  10  can be locked in a fixed extended or fixed retracted position. A process of sliding the screwjack inner member  20  and the affixed bar  21 , provides the course adjustment for the jacking operation. Once the complementary passageway holes  13  and the bar holes  16  are registered together, and a pin  18  is inserted through a registered complementary passageway holes  13  and a bar hole  16 , a jacking device is in a fixed position. This previously stated action is the course adjustment of a slidable adjustable jacking device  10 . Then, a hand crank  17  is rotated for fine adjustment of a load-carrying member  22 . This action of rotating hand crank  17  rotates the jackscrew  25  and extends or retracts the load-carrying member  22 . The slidable adjustable jacking device  10  is mounted onto a trailer  23  using a flange  14  which rests on the top of a trailer surface. Flange mounting openings  15  are utilized to affix a flange  14  to a trailer  23 . 
       FIG. 3  show a slidable adjustable jacking device as viewed from the top. When a bar hole  16 , located in bar  21  are in alignment with a complementary passageway holes  13  located in a passageway  12 , then a pin  18  fixes a passageway  12  and a bar  21  in a fixed position. Then a hand crank  17 , which is connected to a screwjack inner member  20 , is rotated to extend or retract a load-carrying member  22 . Load-carrying member  22  and foot  24  may be raised to a full, retracted position to prevent the load-carrying member  22  and the foot  24  from being damaged.  FIG. 3  also identifies the location of flange mounting openings in the corners of a triangular shaped flange  14 . If it is desired to use a square or rectangular shaped tubular outer member  11 , then there will be an a flange mounting hole  15 , in each corner of the square or rectangular flange  14 . 
       FIG. 4  is a side view of a slidable adjustable jacking device  10  shown resting on a flange  14  in a installed position on a trailer  23 . A load-carrying member  22  is shown in a raised and retracted position. A foot  24  is shown on a bottom of a load-carrying member  22 . If desired, a foot  24  may have a different embodiment such as a wheel. A screwjack inner member  20  and an affixed bar  21  are shown as located inside a tubular outer member  11  and an associated passageway  12 .  FIG. 4  also shows spaced bar holes  16  and complementary passageway holes  13 . There are two sets of complementary passageway holes  13  in passageway  12 . While one set of complimentary passageway holes  13  can be used as a placed to insert pin  18 , the other set of complementary passageway holes may be used to accept a hasp of a lock passed through a passageway  12  with a bar  21  and prevent the theft of a bar  21  and an affixed screwjack inner member  20 .  FIG. 4  also identifies a jackscrew  25  which is connected to a hand crank  17 . The screwjack inner member  20  and an affixed bar  21  may be slid out of the tubular outer member  11  and an associated passageway  12  and completely removed to prevent the theft of the screwjack inner member  20  and an affixed bar  21 . 
     ADVANTAGES 
     The advantage of this present invention is that the operator of the adjustable slidable jacking device can quickly and easily slide a screwjack inner member  20  and an affixed bar  21  into a place where it is aligned with a complementary passageway holes  13  so that a pin  18  might be inserted to cause the relation between a bar  21  and a passageway  12  to remain fixed in relationship to a trailer  23 . The operation of sliding a screwjack inner member  20  and an affixed bar  21 , is the course adjustment in a jacking operation. Once a slidable adjustable jacking device  10  is coarsely adjusted, a hand crank  17  is rotated to extend a load-carrying member  22 . The advantage of this device is that less rotations of a hand crank  17  are required than for jacking devices which do not have a slidable screwjack inner member  20  and an affixed bar  21 . 
     Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. A tubular outer member  11  may be formed in a round shape or in a square or rectangular shape, according to the wishes of the manufacturer. A foot  24  may be a resting pad or a foot  24  may allow for motion, as a wheel would allow for motion. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred version contained therein. 
     The reader&#39;s attention is directed to all papers and documents which are filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All features disclosed in this specification (including any accompanying claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. 
     CONCLUSION, RAMIFICATIONS AND SCOPE 
     It can be seen by the description above the number of rotations of a hand crank on a jacking device may be greatly reduce by using a slidable screwjack inner member to re-position a load-carrying member. 
     While the above description contains much specificity, these should not be construed as limitations on the scope of any embodiment, but as exemplifications of the presently preferred embodiments thereof. Many other ramifications and variations are possible within the teachings of the various embodiments. 
     Thus the scope of the invention should be determined by the appended claims and their legal equivalents, and not by the examples given. 
     SEQUENCE LISTING 
     Not Applicable