Abstract:
A support for supporting equipment includes at least one elongate leg element at least partially supporting an apex selectively, detachably mountable to equipment, where the leg includes a first end proximate the apex and a second end distal the apex, and where the leg is pivotal about an axis proximate the first end throughout a limited arc. A securement assembly pivotably interconnects the first end of the leg with the apex. The securement assembly has selectable resistance to movement along the arc as a result of selectively increasing or decreasing the resistance between at least three friction plates having surfaces in face-to-face engagement with one another.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional App. No. 61/809,093, filed Apr. 5, 2013. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to a portable support apparatus for equipment, such as a tripod. For convenience, the term “tripod” is used as a generic identifier for a more broad class of equipment supports, which may have any number of legs, e.g. a support with two, three, four or more legs. 
         [0003]    Tripods have been used for many years. Typically, tripods include an elevated mounting surface, upon which equipment may be secured, such as a camera, telescope, musical equipment, surveying equipment, antenna, etc. The elevated mounting surface is supported by a plurality of legs, which in the case of a tripod is typically three. Other numbers of legs may likewise be used, such as a single leg monopod. 
         [0004]    Tripods are designed to provide some optimal balance between a set of features. For example, one feature of a tripod is stability, as it is often desirable to insure that shaking or other movement of equipment supported by the tripod is minimized so that, for example, blur does not occur in an image taken by a camera supported on the tripod. Tripods are often used portably, hence, it is often desired to minimize the weight and/or dimensions of the tripod so that it may be carried over great distances. Unfortunately, these stability and weight considerations are often in conflict, i.e. a heavier tripod will provide a high degree of stability but will be more burdensome to carry. 
         [0005]    Many existing tripods are vertically collapsible with radially extendible legs. For example, a tripod may have three leg assemblies, with each leg assembly pivotally connected to an elevated equipment support so that each leg may be pivoted outwards when in use, and inwards when not in use. Also, each leg assembly may have multiple elements that selectively slide axially relative to each other. For example, a multi-stage tripod may have first, second, and third segments for each leg. To adjust the height of the tripod, the first and second leg segments are slidably movable relative to each other and the second and third leg segments are also slidably movable relative to each other. Each pair of legs may be selectively locked and unlocked at different positions. Tripods also may include an adjustable central column to change the height at which equipment is supported by the tripod at a fixed extension of the tripod legs. Further, the tripod legs typically include locking detents so that each of the tripod legs may be positioned at one of a plurality of fixed angular orientations. Unfortunately, the selected detents often do not provide the flexibility to position the tripod legs at the desired positions, especially when using the tripod on uneven or rocky terrain. 
         [0006]    What is desired therefore is a modified tripod, and in particular a modified tripod leg, suitable for being adjustable to a desirable location. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  illustrates a tripod. 
           [0008]      FIG. 2  illustrates a tripod apex together with a exploded view of a securement assembly. 
           [0009]      FIG. 3  illustrates a side view of the apex and securement assembly of  FIG. 2 . 
           [0010]      FIG. 4  illustrates a cut away view along line  4 - 4  of  FIG. 3 . 
           [0011]      FIG. 5  illustrates a more detailed view along line  5  of  FIG. 4 . 
           [0012]      FIG. 6  illustrates a more detailed view along line  6  of  FIG. 4 . 
           [0013]      FIG. 7  illustrates an end view of the apex and securement assembly. 
           [0014]      FIG. 8  illustrates a cut away along line  8 - 8  of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0015]      FIG. 1  shows an exemplary tripod  10 . Though features are discussed in reference to the depicted tripod, it should be understood that the features may be implemented in an equipment support having any number of legs. The tripod  10  may include a platform  12  for detachably securing equipment to the tripod  10  using a set screw or other attachment mechanism. The tripod  10  may include a plurality of legs  14  to support the platform  12  at an elevated position. The platform  12  may be detachably mounted within an apex  18  of the tripod, which may be a ring into which the platform  12  may be secured. Each of the legs  14  may include a plurality of telescoping leg sections that nest together in a retracted position by releasing an appropriate locking mechanism  16 . Although the platform  12  is shown as having a fixed vertical position with respect to the apex  18 , it is understood that the platform  12  may be supported by a vertically-extensible column slidably engaged with the apex  18 . The platform  12  may include a spirit level. Each of the legs  14  preferably pivots about a respective axis proximate the apex  18 . Through a selective choice of respective angles between each of the legs  14  and the apex  18 , along with a desired telescoped length of each respective leg, equipment attached to the tripod  10  may be supported on a wide variety of terrain. 
         [0016]    Two competing characteristics of tripod legs are stability and adjustability. To increase the stability of the tripod legs a discrete set of leg positions may be included to define the available secured positions for the tripod legs. However, such a limited number of secured positions for the tripod legs limits the usefulness of the tripod in rough environments. 
         [0017]    Each of the legs  10  is preferably formed of carbon-fiber material selected for its light weight and high strength. The tripod legs  14  may include a plurality of hollow, nested telescoping sections where the largest section of each leg, into which the other leg sections selectively retract, is preferably less than approximately 3/32 inches thick along a major portion of its length, more preferably less than approximately 0.08 inches thick along a major portion of its length, and even more preferably less than approximately 0.04 inches thick along a major portion of its length. The term “approximately” in this context means within a range of plus and/or minus 10%. 
         [0018]    Referring to  FIG. 2 , the apex  18  portion of the tripod of  FIG. 1  is preferably replaced with a modified apex  100  and a modified securement assembly  102 . The apex  100  includes a central region that can support an imaging device and/or a platform upon which the imaging device is supported. The apex  100  preferably includes a central circular opening defined therein. The apex  100  may include suitable interconnections for a plurality of securement assemblies  102 , such as three securement assemblies. The securement assemblies  102  are each in turn interconnected to a respective leg of the tripod. The apex  100  may also include a level  104  that is secured within an opening  106  defined by the apex  100  so that the viewer can readily determine if the apex  100  is level. 
         [0019]    The securement assembly  102  includes a clevis  108  which is rotatably interconnected with the apex  100  and rigidly interconnected with legs of the tripod. To a left housing  110  of the clevis  108  is a knob assembly including a tension knob  120 , a knob washer  122 , a Belleville washer  124 , a piston  126 , all of which is secured together with a screw  128 . A cap  130  may be placed within the end of the knob  120  to cover the screw  128 . To a right housing  132  of the clevis  108  is a lever assembly including a lever  134 , an axle  136 , and a level washer  138 . The axel  136  is positioned between the right housing  132  and the left housing  110 , with the screw  128  being secured to the axel  136  to secure the knob assembly and lever assembly to the clevis  108 . 
         [0020]    The apex  100  may include a set of supports  140  through which are included a cylinder  142  to support the securement assembly  102  thereon. A first set of friction plates  144  are supported on a bushing  146 , which collectively are supported on the cylinder  142 . Similarly, a second set of friction plates  150  are supported on a bushing  152 , which collectively are supported on the other side of the respective cylinder  142 . The friction plates  144 ,  150  are in face to face engagement with one another such that rotation of one plate with respect to another plate results in a frictional resistance to such movement. A first half of the first set of friction plates  144  include a lower set of protrusions  160 , and a second half of the first set of friction plates  144  include an upper set of protrusions  162 . The first and second halves of the first set may be the same, the difference being the rotation of the respective friction plates. A first half of the second set of friction plates  150  include a lower set of protrusions  170 , and a second half of the first set of friction plates  150  include an upper set of protrusions  172 . The first and second halves of the second set may be the same, the difference being the rotation of the respective friction plates. A wedge  180  is used together with a pair of set screws  182  to maintain the lower set of protrusions  160 ,  170  is a fixed position with respect to the clevis  108 . A wedge  184  is used together with a pair of set screws  186  to maintain the upper set of protrusions  162 ,  172  in a fixed position with respect to the apex  100 . Accordingly, part of the friction plates are maintained in a fixed position with respect to the apex  100  and the other part of the friction plates are maintained in a fixed position with respect to the clevis  108 . 
         [0021]    Each of the friction plates that have the upper set of protrusions are interspaced with each of the friction plates that have the lower set of protrusions in such a manner that there is a plurality of surfaces that may provide frictional resistance to movement along a two-dimensional range of motion when the securement assembly is secured to the apex. Rotating the screw knob selectively increases or decreases the frictional resistance by increasing or decreasing, respectively, the pressure exerted on the stack of friction plates. Thus with low resistance on the friction plates the control arm maybe readily positioned. Then by turning the screw knob, the friction provided by the friction plates may be substantially increased to maintain the tripod leg in a desired position. Also, the frictional resistance is generally linear within the useful operating range of the screw knob. 
         [0022]    Referring to  FIG. 3 , a side view of the apex  100  with one of the securement assemblies  102  in an assembled configuration is illustrated. Referring to  FIG. 4 , which is a cut away view along line  4 - 4  of  FIG. 3 , illustrates in particular more detail of the friction plate assembly. The friction plates are aligned with one another and maintained from substantial rotational movement by the respective screws and/or wedge. Referring also to  FIG. 5 , the right hand screw  186 , together with the wedge  184 , is illustrated as retaining the protrusions  172  in a fixed position. Referring also to  FIG. 6 , the right hand screw  182 , together with the wedge  180 , is illustrated as retraining the protrusions  170  in a fixed position. 
         [0023]    Referring to  FIG. 7 , an end view of the apex with one of the securement assemblies  102  in an assembled position is illustrated. Referring to  FIG. 8 , which is a cut away view along line  8 - 8  of  FIG. 7 , illustrates in particular the interrelationships between the friction plates. 
         [0024]    With the flexible positioning of the tripod legs with respect to the apex, the imaging equipment may be placed in a precise location and located in that position. The positioning may be at any suitable position along the range of movement of the leg. Moreover, to reposition the leg the securement assembly may only be slightly loosened, the leg repositioned, and the leg secured in position. 
         [0025]    All the references cited herein are incorporated by reference. 
         [0026]    The terms and expressions that have been employed in the foregoing specification are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims that follow.