Abstract:
The present invention is a self-locking folding crane apparatus that can be installed onto any pivot shaft and held in place by small positioning devices such as clamps, slip-rings, bolts, shaft collars, pins, and other mechanical means; a substantial base is not needed to support the hoist as long as the pivot shaft is able to do so. The resulting hoist can be recoverably installed and optionally left on a vehicle or cart while it is in either an operative or stowed state. Unlike all other portable cranes that were found in prior art either singly or in combination, the present invention requires no assembly or disassembly between uses.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     None 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     None 
     FIELD OF THE INVENTION 
     The present invention relates to the field of cranes, hoists, and lifting devices. 
     BACKGROUND OF THE INVENTION 
     This invention teaches improvements to portable hoists that are mountable to vehicles, building structures, carts, trailers, and the like. Examples in prior art are abundant and include teachings by Harr and Cary who introduce portable cranes in U.S. Pat. Nos. 5,752,799 and 5,993,137. Kruse teaches a in U.S. Pat. No. 6,007,289 that mounts into a receiver hitch and uses a jig to stabilize and increase the lifting capability of a hoist that is designed for powered mobility chairs. Williams teaches a portable mobility chair crane in U.S. Pat. No. 6,830,423 that engages a vehicle receiver adapter. Robinette teaches a low-pivot-point lift in U.S. Pat. No. 5,211,526 that does not have a hinge point. 
     Spitsburgen teaches a portable lift in U.S. Pat. No. 6,499,610 for medium to heavy applications. The &#39;610 apparatus is readily assembled before each use and can be disassembled after use for easy storage. The Spitsburgen lift is mountable to vehicles, equipment, trailers, and building structures. Griffith teaches recoverable installation of a hitch hoist that is suitable for heavier objects in Canadian Patent 2,108,107. Davis teaches a multi-purpose hoist in U.S. Pat. No. 5,749,697 with top and bottom components mate together during assembly. Likewise Barger teaches a portable crane in U.S. patent application Ser. No. 10/657,029 that is adaptable to shop work benches, vehicles, and other stable structures. Amato teaches a swingable boom-type portable crane in U.S. Pat. No. 4,881,864 that engages the receiver hitch of a vehicle. 
     Compton teaches a collapsible hoist in U.S. Pat. No. 6,152,675 that has a sufficiently high center mast to elevate hunting game; the hoist is assembled, installed, and subsequently removed between uses. A collapsible hoist taught by Perkins in U.S. Pat. No. 6,578,722 also engages a vehicle receiver hitch and has a telescoping mast that is able to achieve a sufficient height to raise tall objects. Phillip and Angel teach similar game hoists in U.S. Pat. Nos. 6,705,821 and 7,201,552. 
     Other exemplary embodiments are described in U.S. Pat. Nos. 6,478,528, 6,386,820, 5,520,498, 5,445,487, 5,014,863, 7,300,238, 6,981,834, 6,860,703, 6,138,991, 6,089,431, 6,082,561, 5,810,547, 5,788,095, 5,800,117, 5,662,451, 4,417,665 and US patent application publication 20110206488. 
     All examples and combinations of examples of portable cranes found in prior art rely on assembly before use and disassembly after use. Among the above listed examples, the &#39;675, &#39;522, &#39;722 and &#39;821 cranes share the additional common drawback that they do not pivot. US Patent Application US2009/0067968 A1 also teaches a portable crane that requires assembly between uses and does not pivot. Prior art is quick to point out that each phase of assembly can be performed in as little as 2 minutes. 
     The present invention unveils a notable improvement by teaching a hoist that unfolds into a usable state in as little as 2 seconds and folds into a stowed state just as quickly. No assembly is required to transition the present invention in an operable state and no disassembly is required to revert the present invention back into a stowed state. To achieve this improvement over prior art the present invention combines a low profile pivoting hinge with latching and stopping surfaces, a hinge mounted mast with latching and stopping surfaces, and a hinge mounted boom with latches and stopping surfaces that automatically lock the hoist into operable and stored states as it is folded or unfolded. Nothing found in prior art or any combination thereof is seen to describe the present invention. 
     BRIEF SUMMARY OF THE INVENTION 
     This invention teaches improvements to foldable hoists by teaching a pivot shaft mountable hoist that unfolds from a stowed state and self locks into a usable state without the need for assembly, latches, fasteners, pins, or connectors. To achieve a folding operation improvement over prior art, the present invention combines a pivot that is hinge coupled to a stanchion in a manner that causes the two pieces to lock against each other and hold the stanchion largely vertical. This pivoting hinge and stanchion configuration is combined with boom and boom lock that are hinge coupled in a manner that causes the boom lock to drop in place and lock the boom against the stanchion when it is unfolded. The boom is locked relative to the stanchion in a manner that maintains a locked configuration between the stanchion and pivoting hinge. The simple step of unfolding the hoist is sufficient to bring it from a folded state into an operative state. Other improvements over prior art include knee-operable rotational load control, safety measures to enable the apparatus to remain assembled and engaged to a receiver hitch while in tow, the capability to fold into a stowed state without additional steps to disassemble or secure the hoist, and a pivoting hinge that is designed to engage the stanchion and pivot shaft in a manner that improves lifting capacity and product safety. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Further features, advantages, and benefits of this invention, as well as the structure and operation of various embodiments thereof, are described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digits in the corresponding reference number. The drawings disclosed herein are illustrative of preferred and sample embodiments of the disclosed invention and are not intended to limit the spirit or scope thereof. 
         FIG. 1  shows a preferred embodiment of the present invention. 
         FIG. 2  shows essential components of a preferred embodiment of the present invention. 
         FIG. 3  shows how mating surfaces are used to lock an embodiment of the present invention into an operable state. 
         FIG. 4  shows a boom lock that is used to lock the boom into an operable state. 
         FIG. 5  shows a boom that is adaptable for use with boom lock of the present invention. 
         FIG. 6  shows how the pivot shaft and pivoting hinge mate in a preferred embodiment of the present invention. 
         FIG. 7  shows a recoverable installable vehicle base mount that engages the pivot shaft of a preferred embodiment of the present invention. 
         FIG. 8  shows a portable base mount that engages the pivot shaft of a preferred embodiment of the present invention to form an engine hoist. 
         FIG. 9  shows a plurality of installation points on a trailer that are adapted to mount a plurality of pivot shafts that can be rotationally coupled the pivoting hinge of the present invention to. 
         FIG. 10  shows an installation point on a work table that is adapted to mount a pivot shaft that can be rotationally coupled to the pivoting hinge of the present invention. 
         FIG. 11  shows a base mount that has a pivot shaft that can be rotationally coupled to the pivoting hinge of the present invention to render the present invention capable of mounting onto a roof, floor, or wall. 
         FIG. 12  shows an optional stowage latch that automatically engages the stanchion as it is folded into base mount of a preferred embodiment of the present invention. 
         FIG. 13  shows an optional stowage latch that engages the boom as it is folded into the stanchion of a preferred embodiment of the present invention. 
         FIG. 14  shows a structural tube that engages the boom of a preferred embodiment of the present invention to form an extendable boom. 
         FIG. 15  shows a kickstand style jig that is mounted to a vehicle receiver hitch adapter of a preferred embodiment of the present invention. 
         FIG. 16  shows a hand-brake winch, a rotational swing lock, and an optional latch that is used to prevent a preferred embodiment of the present invention from unintentionally folding out of an operative state. 
         FIG. 17  shows an electric winch that is mounted to a preferred embodiment of the present invention in a stowed state. 
         FIG. 18  shows a preferred embodiment of the present invention that uses actuators to induce movement. 
         FIG. 19  shows a preferred embodiment of the present invention coupled to an all-terrain vehicle on the load side and to a receiver hitch at the mounting engagement point. 
         FIG. 20  shows a preferred embodiment of the present invention lifting an all-terrain vehicle into the back of a flat-bed truck. 
         FIG. 21  shows a preferred embodiment of the present invention hoisting an elk while a hunter process it. 
         FIG. 22  shows how a preferred embodiment of the present invention leans over while lifting a log that is beyond the lifting capacity of the crane. 
         FIG. 23  shows a preferred embodiment of the present invention mounted to a sedan style vehicle. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention is a portable crane that is able to fold in and out of operative states without the need for assembly or disassembly between uses and is able to remain assembled while in tow. Essential components of this invention include a pivot shaft  240 , boom lock  220 , load coupler  250 , and an assembly comprising a stanchion  210 , pivoting hinge assembly  230 , and boom  260 ; all having contact surfaces that engage to lock the hoist into an operative state when it is unfolded. 
     Embodiments of this invention are shown unfolded into an operative state in  FIGS. 19  thru  22  in the drawings. The stanchion generally rests in a horizontal position when folded into a stowed state. Embodiments of this invention are shown folded into a stowed state in  FIGS. 16  thru  18 . 
     The term “stanchion” refers herein to a component of the hoist  210  that operates as a substantially vertical mast when the hoist is unfolded into an operable state. The stanchion  210  of the present invention has a contact surface at the proximal end  211  that engages the distal surface of a pivoting hinge  231  to lock the hoist as it is unfolded. The stanchion  210  also has a locking surface at the distal end  212  that engages the proximal surface  221  of the boom lock. The pivoting hinge  230  and the boom lock  220  are defined below. 
     The term “pivoting hinge” refers herein to a component  230  that is hinge coupled to the proximal end of the stanchion  210 , has a substantially horizontal distal surface  234  that engages the locking surface at the proximal end  211  of the stanchion as it is unfolded into a locked operative position.  FIG. 3  shows how the pivoting hinge  230  and the stanchion  210  are assembled and how the locking surfaces of each component mate as a preferred embodiment unfolds. 
     The term “pivot shaft” refers herein to a substantially cylindrical shaped shaft  240  that is rotationally coupled to a pivoting hinge  230  and physically coupled to any structure capable of supporting the hoist  770 ,  901  and load when the hoist is in use.  FIG. 6  shows how the pivot shaft in one embodiment is passed through the pivoting hinge to form a rotationally coupled union between both components.  FIG. 7  shows a plurality of open cylinders  770  that can be engaged by a cylindrical shaped open shaft and a cylindrical shaped pivot shaft  240  equipped with a pivoting hinge positioning nut  902  and adaptively coupled to one of the cylinders  770  that can be rotationally coupled directly to the pivoting hinge  230 . The cylindrical shaped pivot shaft  240  can also be welded or mechanically coupled to the trailer in this example without engaging one of the open cylinders  770 . 
     The term “boom” refers to a lifting arm  260  that is adaptively coupled to a load coupling device  250  when the hoist is in use. The boom  260  is substantially horizontal in both operational and stowed states in preferred embodiments of this invention. 
     The terms “boom lock” refers to a latch  220  that is hinged coupled at the proximal end  221  to the proximal region  261  of the boom  260  and has at least one locking surface at its distal end  222  that engages a locking surface near the proximal end  212  of the stanchion  210  as this invention is unfolded into an operable state. 
     The term “mounting base” refers to any structure that is capable of supporting the crane assembly and load during use and adaptable to be rotationally coupled to the pivoting hinge  230 . The mounting base can be a male cylindrical shaft capable of direct engagement to the pivoting hinge or a female cylindrical opening  710 ,  810 ,  910 ,  1010 ,  1110  capable of engaging a male cylindrical shaft that is already rotationally coupled to the pivoting hinge. 
     The term “insert adapter” refers herein to a substantially horizontal component of the base mount  711  that is designed to engage a vehicle adapter such as a receiver hitch during recoverable installation and removal. 
     Preferred embodiments of the present invention employ additional latches  1210 ,  1310 ,  1610 , jigs  1510 , boom extenders  1410 , actuators  1810 , and winches  1630 ,  1710  to improve performance or utility of the present invention for specific applications. 
     The term “base latch” refers herein to a latching mechanism  1210  that engages and secures the distal end  211  of the stanchion  210  to any surface on the mounting base as the present invention is folded into a stowed state. 
     The term “stanchion latch” refers herein to a latching mechanism  1310  that engages and secures the stanchion  210  to the boom  260  as the present invention is folded into a stowed state. 
     The term “boom extender” refers herein to an insert  1410  that is preferably attached to a load coupler and can be inserted into the boom  260  to collectively extend the reach of the boom  260 . The adaptively coupled position of boom extender  1410  inside the boom  260  is adjustable in preferred embodiments. 
     The term “kick-stand jig” refers herein to a hinge mounted jig  1510  that operates substantially in the same manner as a kick-stand. The jig relies on a spring  1520  or other means of mechanical tension to force the jig to snap into operable and stowed states. The top of the jig includes an upper surface that engages and locks to a lower surface on the mounting base when the jig is unfolded into an operable state. 
     The term “rotational swing lock” refers herein to a rotational latch  1620  at the base of the pivoting hinge that is capable of adaptively coupling with a plurality of surfaces  1621  at the proximal end  211  of the stanchion  210  or the proximal end  235  of the pivoting hinge  230  to control pivotal rotation. 
     The term “tilt lock” refers herein to a releasable latch  1610  at the proximal end  211  of the stanchion  210  that engages a locking surface  233  on the pivoting hinge  230  to prevent the stanchion  260  from folding backward into a stowed state while it is unfolded into an operative state. 
     Preferred Embodiments 
     In preferred embodiments, the pivoting hinge  230  serves as a supporting stop for the stanchion  210  as it is unfolded, the boom lock  220  drops and locks into place as the lifting arm  260  is raised into operating position, and safety latches  1210 ,  1310  engage the stanchion  210  and boom  260  when it is folded back into storage. Preferred embodiments position the pivoting hinge  230  at a low elevation on the structure to give a folded embodiment of the present invention a low profile. 
     Preferred embodiments rely on two essential features to improve lifting capacity and operational safety; namely a pivoting hinge  230  that adaptively couples to the stanchion  210 , and a pivot shaft  240  that is rotationally coupled through the pivoting hinge  230 . The pivoting hinge  230  and pivot shaft  240  mate by passing the pivot shaft  240  through a substantially vertical cylindrical opening in the pivoting hinge  230 . In preferred embodiments the vertical height of the cylindrical opening on the pivoting hinge  230  is substantial enough to distribute force along the shaft  240 . 
     In preferred embodiments, the pivot shaft  240  is designed to be a weak point in the apparatus that slowly bends to lower a load that is heavy enough to induce failure in the crane. The sample illustration in  FIG. 22  shows how a properly designed pivot shaft allows the stanchion  260  to lean over and lower the load as an oversized log  2210  induces failure in the hoist. 
     Assembly of the essential components comprises the steps of rotationally coupling the pivoting hinge  230  and pivot shaft  240  as shown in  FIG. 6 , hinge coupling the pivoting hinge  230  to the proximal end  211  of the stanchion  210  as shown in  FIG. 3 , hinge coupling the proximal end  261  of the boom to the distal end  212  of the stanchion as illustrated in  FIG. 13 , hinge coupling the proximal end  221  of the boom lock  220  to the proximal region  261  of the boom  260  as shown in  FIG. 16 , and adaptively attaching a load coupler  250  to the distal end  262  of the boom  260  as shown with an optional boom extender  1410  in  FIG. 14 . The above assembly is then adaptively coupled to an insert  770 . The exemplary insert adapters  770  shown in the Figures are for illustrative purposes and are not intended to limit the scope of this invention. 
     A preferred assembly of the pivot shaft  240  and pivoting hinge  230  is shown in  FIG. 6 . The pivot shaft  240  optionally has a cold-head, nut, clamp, pin, slip-ring, or other mechanical fastening device at the distal end  241  to prevent the pivoting hinge  230  from slipping off. Slip rings, pins, threaded adapters, shaft collars and the like  243  affixed to the pivot shaft  240  are preferably used to vertically position the proximal base of the pivoting hinge  235  on the pivot shaft  240 . In preferred embodiments the pivoting hinge  230  spans a distance along the pivot shaft  240  that is greater than or equal to the diameter of the pivot shaft  240 . A pivoting hinge  230  may span a shorter distance along the pivot shaft  230  for embodiments of this invention that are intended for lighter loads. Select embodiments include a mechanical means to couple the pivot shaft  240  to a mounting base  770  at the distal end  242  of the pivot shaft. The exemplary embodiments shown in the figures use a fastening pin. 
     Preferred embodiments of the pivoting hinge  230  have a substantially horizontal upper surface  234  that engages the proximal end  211  of the stanchion as it is unfolded into a locked operating position. The upper surface  234  of the pivoting hinge is optionally angled slightly downward toward the proximal end  232  of the pivoting hinge  230 . The distal end  234  of the pivoting hinge  230  preferably has a substantially horizontal locking surface  233  that engages a tilt lock  1610  to prevent unintentional folding of the stanchion  210  when in use. 
     The pivoting hinge  230  and stanchion  210  are preferably hinge coupled in a manner that maximizes surface contact between the distal end  211  of the stanchion  210  and the upper surface  231  of the pivoting hinge  230 . An exemplary embodiment of the pivoting hinge  230  and stanchion  210  assembly is shown in  FIG. 3 . 
     Preferred embodiments of the boom lock  220  include a hinge coupling point at the proximal end  222  and a locking surface at the distal end  221  that engages a locking surface at the proximal end  212  of the stanchion  210 . Bends and gussets along the edges of the boom lock  220  are preferably used to enhance strength. 
     Preferred boom  260  embodiments include a hinge coupling point  264  that is offset slightly from the center of the proximal end  261  as shown in  FIG. 5 . The boom  260  embodiment shown in  FIG. 5  includes handles  263  for transporting and operating the hoist and for coupling to the stanchion latch  1310  shown in  FIG. 13 . 
     Preferred base latch embodiments  1210  include a spring affixed to the latch to ensure proper engagement to a mating surface  712  on the mounting base  710 . 
     Embodiments of the pivot shaft are adaptively attachable to any plurality of mounting bases. Exemplary embodiments of mounting bases include a vehicle receiver hitch mounting base  710 , a base to a portable cart or portable engine hoist  810 , mounting base attachments for trailers and portable carts  910 , adaptable inserts for tables or working benches  1010 , and adaptable inserts for roof, floor, and wall mounts  1110 . 
     The mounting base embodiment  710  shown in  FIG. 15  is well suited for use with vehicles that have a receiver hitch. The mounting base  710  includes a substantially horizontal tube with an adapter at the proximal end  711  intended for recoverable engagement into a vehicle receiver hitch and an insert adapter  770  at the proximal end  712  that adaptively couples to the pivot shaft  240 . 
     Preferred embodiments of the receiver hitch adaptable mounting base  710  include a kick-stand style jig  1510  at the distal region  712  of the mounting base  710 . The kickstand jig includes a hinge coupling point that is offset from the distal end  1511 , a plurality of segments  1513 ,  1514  that provide height adjustment, a base at the proximal end  1512 , and a spring  1520  or other mechanical means to force the kickstand jig to snap into operable and stowed states as it is folded and unfolded. 
     Accessories such as hand-brake winches  1630 , electric winches  1710 , and actuators  1810  are interchangeably attachable to preferred embodiments of the present invention. 
     Preferred Methods 
     Essential steps of the preferred method include disengaging latches and locks and unfolding the apparatus from a stowed state, ensuring that all latches and locks that lock the hoist into an operative state are engaged before use, coupling the apparatus to a load, raising the load, optionally engaging a rotational latch to control pivotal rotation, swinging the load into a desired position, lowering the load, uncoupling the hoist from the load, swinging the hoist over the mounting base, and disengaging all latches and locks that lock the hoist into an operative state, folding the apparatus back into a stowed state, and ensuring that all latches and locks that lock the apparatus into a stowed state are engaged. 
     It is optimal to use this invention on a level surface to minimize the threat of damage to the hoist, host vehicle, or payload and further to impede the threat injury to the hoist operator. If this invention is used on an uneven surface, a preferred method is to level the hoist by making height adjustments to the kickstand jig  1510 . If a load must be lifted from an uneven or un-level surface, a preferred method to prevent damage or personal injury is to engage the rotational swing latch until the load can be transported to a level surface. 
     Exemplary Uses of Preferred Embodiments 
     The present invention is well suited for most lifting applications. Spreaders  1920  should be used when lifting large objects such as lawn mowers, equipment, or all-terrain vehicles  1910 . The kickstand style jig should also be deployed when lifting heavy loads; particularly those that approach the limit of the device that supports the mounting base. More than one lifting point should be used on the load as shown in  FIG. 20  when using the present invention to lift large objects that may be difficult to control. 
     The present invention is well suited for hunting applications and can be used to winch in large game and to subsequently elevate the animal for processing. The exemplary application in  FIG. 21  shows a bull elk that has been hoisted so that it can be processed in the field by a hunter. The lifting capacity of the embodiment shown in the figure exceeds the weight of the animal. This embodiment enables an individual hunter to process and load the large animal into a vehicle without assistance. 
     If the present invention is used to lift logs or other durable items, it may be beneficial to simply wrap the lifting cable of the hoist around the load and use the load coupling hook to form a noose with the cable as shown in  FIG. 22 . Caution should be exercised to ensure that the load, the hoist, and the host vehicle are capable of supporting the load. 
     The present invention is well suited for lifting powered mobility chairs and other light loads when affixed to the rear of a vehicle as shown in  FIG. 23 . Caution should be exercised to ensure that the load, the hoist, and the host vehicle are capable of supporting the load. 
     It is understood that the above embodiments and applications are merely illustrative of the possible specific applications which may represent principles of the present invention. Other embodiments may readily be devised in accordance with the principals herein by those skilled in the art without departing from the scope and spirit of this invention.