Patent Publication Number: US-2007095611-A1

Title: Elevating Tree Stand

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 60/731,184 filed Oct. 28, 2005, the entire disclosure of which is herein incorporated by reference.  
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This invention relates to a lift system for raising or lowering a platform. In particular, the apparatus provides a generally vertical beam against which a generally horizontal platform is constrained and along which the platform can move as the platform is raised or lowered by a winch or other means connected to the platform and having a cable running to near the top of the generally vertical beam.  
      2. Description of Related Art  
      Small, elevated, outdoor platforms that may be used for hunting or wildlife viewing are well known, in part because of their ease of construction and largely because of their great utility. Most often such a platform is built onto a tree, which provides the primary support therefor. A substantial disadvantage of such an elevated platform is that access is generally limited, most often being provided only by a ladder. Not uncommonly such ladder access is provided by only a primitive form of a ladder.  
      For hunters (or others wishing to use an elevated platform) who are not sufficiently agile, strong, steady, sturdy, or are otherwise of limited ability, a climb on a primitive ladder, or any ladder, may be daunting or impossible. For instance, persons with a physical disability or who are elderly may want to utilize such an elevated platform yet be unwilling or unable to climb to it. Even for persons willing and able to climb to an elevated platform, the climb may be dangerous. Injury from slips or falls while climbing a ladder is a well-known hazard. In fact, a professional analyst and commentator on the sport of hunting has suggested that as many as one-fifth of all hunters using ladders to access a stand will be injured.  
     SUMMARY OF THE INVENTION  
      The following is a summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not intended to identify key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.  
      Instead of requiring a person to climb to an elevated platform, embodiments of the invention provide a lift system wherein the platform can be positioned low enough to the ground that a person can directly step or roll (as in the case of a person in a wheeled chair or other vehicle) onto or sit upon it, after which the platform, along with the person, can be raised into an elevated position.  
      In an embodiment, a portable, elevating stand comprises a generally columnar upright support having a height, the support including at least two flange portions projecting therefrom along at least a majority of the height; a platform assembly on which a user may stand or sit, the platform assembly being movably connected to the at least two flange portions of the support; and a means for raising and lowing the platform along the height of the column. In an embodiment, the at least two flange portions are comprised by a unitary plate portion mounted flush against a flat side of a tube portion of the generally columnar upright support. In an embodiment the tube portion has a square or rectangular cross section. In a further embodiment, the platform assembly includes at least two channels, each of the channels being sized and shaped to slidably engage at least one of the at least two flange portions; and wherein the channels are slidably engaged with the at least two flange portions, thereby constraining the platform assembly to move generally along the height of the column. In an embodiment, such a channel is constructed through the connection, in a stacked arrangement, of a main support plate, a spacer plate, and a flange keeper plate. In an embodiment, the generally columnar upright support comprises one of an I-beam, an angle iron, two angle irons attached back-to-back to form a shape generally described by a T, or a structure the shape of which is generally described by a double-T. In an embodiment, the stand further comprises a brake mechanism including one of a locking pin or a brake plate.  
      In an embodiment, the means for raising and lowering is a winch mounted on the platform assembly so as to be raised and lowered along with the platform assembly. In an alternate embodiment, the stand further comprises a hand-held electric drill connected to the winch through a gear set.  
      In a further alternate embodiment, a portable, elevating stand comprises an upright support having a height; a platform assembly on which a user may stand or sit, the platform assembly being movably connected to the upright support along the height thereof; a winch mounted on the platform assembly, the winch including a cable that traverses a distance from a drum of the winch to an attachment near a top of the support; and a hand-held electric drill operably engaged with the winch in a manner such that operation of the drill operates the winch and thereby effects at least one of the raising or lowering of the platform assembly along the height of the support. In an embodiment, the upright support comprises at least two flange portions projecting therefrom along at least a majority of the height; and the platform assembly is movably connected to the support only through connection to the at least two flange portions. In an embodiment, the support comprises a tube portion having a square or rectangular cross-section to which is attached flush against a flat side thereof a plate portion comprising the at least two flange portions, the shape of the support being that of a box-T.  
      An embodiment is a method of raising and lowering a portable, elevating stand comprising providing a portable, elevating stand that comprises a generally columnar upright support having a height; a platform assembly on which a user may stand or sit, the platform assembly being movably to the support; and a means for raising or lowing the platform along the height of the column; carrying a portable, electric motor and power source onto the platform; engaging the motor with the means for raising and lowering; and operating the motor engaged with the means for raising and lowering to effect raising or lowering of the platform. In an embodiment of such method the portable, electric motor is comprised by a hand-held drill, and the power source is a battery or fuel cell. In an alternate embodiment, the means for raising and lowering is a winch.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  shows a plan view of an embodiment of a lift system.  
       FIG. 2  shows a perspective view of an embodiment of a linkage assembly  
       FIG. 3 , including FIGS.  3 A-B, shows cross sectional views of embodiments of upright supports having a generally box-T design, along with their engagement with a linkage assembly.  
       FIG. 4 , including FIGS.  4 A-D shows cross sectional views of embodiments of upright supports that do not include a hollow enclosed space, along with their engagement with a linkage assembly.  
       FIG. 5  shows alternate embodiments of a brake assembly, including a brake plate in  FIG. 5A , a wedge in  FIG. 5B , a pin in  FIG. 5C , and a.cam in  FIG. 5D .  
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
      As shown in  FIG. 1 , an embodiment of the portable, elevating tree stand comprises a seat  21 , otherwise referred to as a sitting platform  21  for sitting upon, and a standing platform  23  connected thereto for standing upon or resting one&#39;s feet while sitting on the seat  21 . Connected to the seat  21  and standing platform  23  is a winch  25 . In this embodiment, the seat  21 , the standing platform  23 , and the winch  25  are part of the platform assembly  22 , which is connected to a generally columnar upright support  27 , along which the platform assembly  22  can move up and down. The platform assembly  22  is suspended above the ground by a cable  29  that is secured on one end to the winch  25  and on the other end to an attachment near the top of the upright support  27 . Specifically as shown in  FIG. 1 , the cable of this embodiment is attached at the top of the upright support  27  to a generally horizontally projecting bar  31 .  
      Configured as shown in  FIG. 1 , operation of the winch  25 , which may be manual or automatic (for example operated by a hand crank or an electric motor, respectively) serves to raise and lower the platform assembly  22  as the cable  29  is respectively wound onto or unwound from the drum of the winch  25 , thereby shortening or extending the length of the cable  29 . Operation of the winch  25  allows the platform assembly  22  to be raised or lowered only to the point of reaching a stop  32  mounted on the upright support  27 . In alternate embodiments the cable  29  is a multi-strand steel cable, a chain, or a rope. In a preferred embodiment, the cable  29  is a strap, such as a nylon webbing material, which is light weight and rolls onto the drum of the winch quietly. Throughout this disclosure the term cable is used as a generic term for any such specific embodiment of the cable  29 .  
      Alternate embodiments of the portable, elevating tree stand include further convenience features on the platform assembly  22 , such as a gun or shooting rail, a safety railing for preventing a user from falling off the platform assembly  22 , or a sound deadening structure constructed about the winch  25 .  
      In a preferred embodiment, the platform assembly  22  is slidably engaged with the upright support  27  via a linkage assembly  72 , a particular embodiment of which is shown in perspective view in  FIG. 2 . As shown in  FIG. 1 , the linkage assembly  72  connects to the standing platform  23  via a support structure used to mount the winch  25 . This support structure, which supports the winch  25  in the embodiment shown in  FIG. 1 , also is used in an embodiment for supporting a battery, for example, a 12 V battery as is used for a automobile or all-terrain vehicle, that provides the power to operate a motor driven winch.  
      In an embodiment, the winch  25  is a manually operated winch driven by a hand crank. In an alternate embodiment, the winch  25  is a motor driven winch. In an embodiment, a motor driven winch may be alternately manually driven, as, for instance, in the event of a motor failure. A motor driven winch will generally be driven by an electric motor powered by a battery as discussed above. In an alternate embodiment, the manual drive engagement socket of a winch  25  is driven by a portable electric motor carried onto the platform assembly  22  at the time of use. In a particular embodiment, the portable electric motor is comprised by a hand-held electric drill. In an embodiment, such a portable motor, whether or not embodied in a drill, is powered by a rechargeable battery, while in alternate embodiments, alternate power sources, such as a fuel cell, are used to power the portable motor. In an embodiment using a drill to drive the winch  25 , the drill produces at least 400 inch-pounds of torque, and is connected to the winch  25  via a gear set that includes a worm gear to provide a 20:1 ratio between revolutions of the drill drive and the winch drive.  
       FIG. 3  illustrates, in a cross-sectional view from above, the connection between the linkage assembly  72  and the upright support  27  in a preferred embodiment. The cross-section of the upright support  27  shown in  FIG. 3  indicates a box-T design for the upright support  27 , formed by the components of the upright support  27 , a square tube  77  and a unitary slide plate  79  rigidly attached thereto flush against a side of the square tube  77 . In this embodiment, the extension of the slide plate  79  beyond the sides of the tube  77  forms flanges  81  on either of two sides of the upright support  27 .  
      This preferred box-T design ( FIG. 3 ) is particularly advantageous in that it is both strong and light weight. This box-T design allows the upright support  27  to readily support a significant amount of weight on the platform assembly  22  without significant deformation to the upright support  27 , yet provides for a relatively small, relatively light weight and therefore relatively easily portable structure. The relatively small but strong box-T design allows the upright support  27  to take up relatively little volume, either when assembled and in use or when disassembled in stored. In a preferred embodiment of the box-T design, the square tube  77  is one and one half inches on a side, and the slide plate  79  is three inches wide, both constructed of steel and welded together.  
      Whereas the upright support  27  depicted in  FIG. 3  comprises a tube of square cross section, in alternate embodiments the tube has a cross section of alternate shape, including other geometric shapes, such as being rectangular, triangular, circular, or oval, for example. Still other embodiments of the upright support  27  do not include a tube. Example cross sections are shown in  FIG. 4  for alternate embodiments of the upright support  27  that do not comprise a tube.  FIG. 4A  shows two angle irons attached back-to-back to form a shape generally described by a T.  FIG. 4B  shows a structure generally described by a double-T (i.e., TT).  FIG. 4C  shows an I-beam structure.  FIG. 4D  shows an angle iron for the upright support  27 . Each of these embodiments has in common the existence of flange portions  81  to which a linkage assembly can be connected. Each of these alternate structures provide the advantages of being relatively small, light weight, and strong, as well as providing the flanges needed for sliding engagement between the linkage assembly  72  and the upright support  27 .  
      In the preferred embodiment shown in  FIG. 3A , the linkage assembly  72  comprises a main support plate  71 , which in an embodiment of the lift system is rigidly attached to the standing platform  23 . The linkage assembly  72  also comprises spacer plates  73 , and flange keeper plates  75 . In this embodiment, the structure of the linkage assembly  72  is such that the flange portions  81  of the slide plate  79  of the box-T upright support  27  fits within a channel  78  of the linkage assembly  72  created between the flange keeper  75  and the main support plate  71  as a result of the spacer  73 . Opposing faces of the flange keeper  75  and the main support plate  71  define the channel walls. This construction allows the linkage assembly  72  to be slidably engaged with the upright support  27 , further allowing the linkage assembly  72  and the attached platform assembly  22  to slide vertically along the height of the upright support  27 .  
       FIG. 3B  shows an alternative embodiment in which the channels  78  of the linkage assembly  72  are formed by a single piece of material shaped to wrap around the flange portion  81  of the upright support  27 , eliminating independent spacer plates  73  and flange keeper plates  75 . The embodiments depicted in  FIG. 4  also show this channel design. Regardless of the specific channel design, in preferred embodiments the channel is sized and shaped to allow in the range of about 1/100th of an inch to about 1/32nd of an inch of space between any channel wall and the flange portion  81  of the upright support  27  when the linkage assembly  72  is slidably engaged with the upright support  27 . Also regardless of the specific channel design, in alternate embodiments, a coating of Teflon or other smooth, low-friction material is provided on the channel walls, or the faces of the flanges that interact with the channel walls during sliding, or both. In further alternate embodiments the linkage assembly  72  includes rollers that directly engage the slide plate  79  and allow rolling engagement rather than sliding engagement between the upright support  27  and the platform assembly  22 .  
      A further component of the lift system depicted in  FIG. 1  is a brake assembly. In this embodiment the brake assembly is designed to be operated by a force exerted on a brake pedal  19  by a user, who is sitting or standing on the platform assembly  22 . Several alternate embodiments of the brake assembly are shown in  FIG. 5 .  
      In an embodiment shown in  FIG. 5A , the brake assembly comprises a brake plate  125  having a flat surface positioned generally parallel and adjacent to, but biased by a spring  127  away from, the slide plate  79  of the upright support  27 . The brake assembly in this embodiment is operated by a user, who is sitting or standing on the platform assembly  22 , pushing on a brake pedal  19  that is connected to the brake plate  125  through a lever arm  20 , thereby overcoming the biasing effect of the spring  127  and forcing the brake plate  125  against the slide plate  79 . In this embodiment, frictional forces between touching surfaces of the brake plate  125  and the slide plate  79  are adjusted depending on the pressure a user applies to the brake pedal. In the event of a malfunction of the elevating mechanism (e.g., winch  25  and cable  29 ), the frictional forces between the brake plate  125  and slide plate  79  can be made, by pressure applied to the pedal  19 , sufficient to slow or stop any decent of the platform assembly  22  due to gravity. This brake mechanism could also be used with the opposite bias, such that a user would have to apply a force (such as through a brake pedal) to overcome a biasing of the brake plate  125  against the slide plate  79  in order for the winch to readily raise the platform assembly  22 .  
      Alternate embodiments of the brake assembly are depicted in FIGS.  5 B-C. An alternate embodiment of the brake plate embodiment just discussed is depicted in  FIG. 5B , which depicts an embodiment comprising a wedge  131 , which, for instance, can be forced upwards from below into the channel  78  of the linkage assembly  72 , for instance in the embodiment shown in  FIG. 3A , between the main support plate  71  and the slide plate  79 , thereby creating a frictional force among the linkage assembly  72 , wedge  131  and slide plate  79  that opposes the downward pull of gravity and can slow or stop the downward movement of the platform assembly  22 .  
      The brake embodiment of  FIG. 5C  is a pin assembly, which uses a spring  141  to bias the pin  143  either towards or away from the slide plate  79 . In the embodiment of the lift system shown in  FIG. 1 , for instance, the brake assembly embodiment shown in  FIG. 5C  could be mounted on the main support plate  71 . One method of use of this embodiment includes the engagement of the pin  143  with one of a plurality of holes in the slide plate  79 . In such an embodiment, wherein the pin  143  is biased toward the slide plate  79 , the user would apply a counter force to overcome the bias of the spring  141 , such as by pulling on a release handle  145 , thereby preventing the pin  143  from engaging a hole in the slide plate  79  and allowing the winch  25  to raise the platform assembly  22 . In such an embodiment, when the release handle  145  is not engaged by a user, the platform assembly  22  can only move downward under the force of gravity until the pin  143  aligns with a hole in the slide plate  79 , at which point the spring  141  will force the pin  143  to engage the hole, and the platform assembly  22  will be stopped.  
      A further alternate embodiment of the brake is shown in  FIG. 5D , which is a cam assembly. This cam assembly brake operates in a similar manner to a mountain climber&#39;s ascender, allowing movement in one direction and halting movement in the opposite direction, though the mechanism has been adapted to the unique environment of the elevating tree stand, as discussed below. In an embodiment, as discussed below, this cam assembly brake is the preferred brake mechanism because it is completely automatic, not requiring any user intervention during elevation of the platform assembly  22 , while maintaining contact with the upright support  27  and thereby operating instantaneously as a brake when upward movement of the platform assembly  22  halts.  
      As shown in  FIG. 5D , in a preferred embodiment the cam  151  is mounted on a backing plate  159  to rotate about an axis  155  and is biased by a spring  127  to a position generally abutting against an upright support  27  (not shown). In an embodiment, the backing plate is rigidly attached to the platform assembly  22  in such a way that when the platform assembly  22  is connected to the upright support  27  as discussed above, a flange portion  81  is positioned between the cam  151  and the side plate  157 . As the platform assembly  22  moves upwardly along the upright support  27 , a generally downward frictional force is generated by the flange portion  81  on the cam  151 , tending to rotate the cam  151  away from the upright support  22 , and allowing the platform assembly to be elevated without binding the cam  151  and without user intervention. As the platform assembly moves downward, however, a generally upward frictional force is generated by the flange portion  81  on the cam  151 , tending to rotate the cam  151  towards the upright support  27  and cause the cam  151  to bind against the upright support  27 , thereby stopping the downward movement of the platform assembly  22 . To allow downward movement of the platform assembly  22 , the user must force the cam  151  to rotate against the bias of the spring  127 , such as by creating a force that pulls downward on the cable  153 , thus moving the cam  151  away from engagement with the upright support  27 , and prohibiting the cam  151  from binding against the upright support  27 . In other embodiments, the user may use any other mechanism known or later developed to rotate the cam  151  against the bias of the spring  127  in order to allow the platform assembly  22  to descend, including a lever directly attached to the cam  151 .  
      In an embodiment, the upright support  27  is held in a generally vertical orientation by attaching the upright support  27  to a tree. In an embodiment, attachment to a tree is facilitated by stabilizers  33 , which are rigidly attached to the upright support  27  and project in a generally horizontal direction that is generally opposite to the direction of projection of the bar  31  at the top of the upright support  27 . In various embodiments, the stabilizers  33  have a shape generally defined by a V, including having an opening between two generally opposing surfaces or edges, which surfaces or edges define an angle. When the upright support is attached to a tree, the stabilizers  33  are mounted against the tree with the tree positioned in the opening between the opposing surfaces or edges, which contact the tree. In alternate embodiments, the stabilizers  33  have a generally curved configuration, generally like that of a U, wherein the surfaces or edges  35  are generally defined by arcs that fit about a portion of a tree&#39;s circumference, for instance. The commonality among embodiments of the stabilizers is projections which can be attached to an upright object, such as a tree, to provide enhanced stability to the upright support  27  when the upright support  27  is to be maintained in a upright position for use in supporting the generally vertical movement of a platform assembly  22 .  
      Various methods of securely attaching a stabilizer  33  to the upright support  27  may be used, including welding. Additionally, various methods of connecting a stabilizer  33  to a vertical support, such as a tree, may also be used, including, for example, a rope, cable, chain, or strap connecting generally from one opposing surface or edge to the other opposing surface or edge of the same stabilizer  33  around a tree. In the preferred embodiment shown in  FIG. 1 , there are four stabilizers  33  along the height of the upright support  27 . As shown in  FIG. 1 , stabilizers  33  may be placed vertically closer together near a joint in the upright support  27 .  
      In alternate embodiments, the upright support  27  is held in a generally vertical orientation by other methods as are well known in the art, such as connection to other vertical structures, or as a free-standing upright support supported by outriggers or a base. Such embodiments are shown in U.S. Pat. No. 5,595,265, which is wholly incorporated herein by reference.  
      In an embodiment, the entire lift system is able to be sufficiently disassembled that the assembly components can be stored and transported in a storage compartment of a vehicle, such as the trunk of a standard passenger automobile, the bed of a pick-up truck, or the cargo area of a sport-utility vehicle. In an embodiment, this transportability is effected in part by the fact that the upright support  27  is constructed of at least two pieces. In a preferred embodiment, the upright support  27  is about sixteen feet in total height and is constructed of three pieces, one of which is about six feet in length and two of which are about five feet in length. The joints at which any two of the components of the upright support  27  fit together are constructed by any reasonable method known in the art that maintains the stability of the upright support  27  and the general continuity of the slide plate  79 . The stability of the joint may be enhanced by the stability provided by the stabilizers  33 , when the stabilizers  33  are used as described above and as shown in the figures. In an additional embodiment, a joint support  34  is included at the joint, as is shown to be located internal to the tube  77  in  FIG. 1 .  
      While the invention has been disclosed in conjunction with a description of certain embodiments, including those that are currently believed to be the preferred embodiments, the detailed description is intended to be illustrative and should not be understood to limit the scope of the present disclosure. As would be understood by one of ordinary skill in the art, embodiments other than those described in detail herein are encompassed by the present invention. Modifications and variations of the described embodiments may be made without departing from the spirit and scope of the invention.