Abstract:
An adjustable pivot joint includes rotation arms which, when locked, prevent pivoting about an axis. A release mechanism is used to unlock the rotation arms to allow pivoting about the axis for adjustment of the pivot joint. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a pivot joint. More specifically, the present invention relates to an adjustable pivot joint mechanism having a releasable locking structure.  
           [0003]    2. General Background and State of the Art  
           [0004]    There are many examples of pivot joints in the marketplace today. Most existing products include two halves fastened together which pivot about a particular point. Some of these products include a locking mechanism which, when released, allows the pivot joint to move about a particular point. However, many pivot joints fail over time due to frequent twisting between two half joints. Other pivot joints are heavy and expensive to manufacture.  
         INVENTION SUMMARY  
         [0005]    In one aspect of the present invention, a pivot joint includes a first rotation arm and a second rotation arm, the first rotation arm coupled to an engagement piece having at least one portion with an angled perimeter, and the second rotation arm having a locking portion also having an angled perimeter, wherein the angled perimeters of the at least one portion of the engagement piece and the locking portion allow the locking portion to receive the engagement piece to provide a locking mechanism for the pivot joint. The pivot joint also includes a pivot piece about which the first rotation arm and the second rotation arm are rotatable, and a spring mechanism positioned around the pivot piece and between the first rotation arm and the second rotation arm. A release mechanism of the pivot joint has a series of pins, the second rotation arm having a series of holes through which the series of pins are positioned, wherein the series of pins extend through the series of holes to move the engagement piece against the spring mechanism and out of the locking portion when the release mechanism is activated to allow at least one of the first rotation arm and the second rotation arms to move relative to the other.  
           [0006]    In another aspect of the present invention, a pivot joint includes a rotation mechanism having a first rotation arm coupled to an engagement piece and a locking portion recessed within a second rotation arm, the engagement piece having a plurality of teeth, and the locking portion having a plurality of grooves, such that when the engagement piece is positioned within the locking portion and the plurality of teeth and the plurality of grooves are aligned together, the rotation mechanism lockably engages the first rotation arm and the second rotation arm. The pivot joint also includes a release mechanism configured to disengage the first rotation arm and the second rotation arm by removing the plurality of teeth from the plurality of grooves when a spring mechanism positioned between the first rotation arm and the second rotation arm is compressed.  
           [0007]    In yet another aspect of the present invention, a method of pivoting a joint apparatus includes providing a first rotation arm and a second rotation arm, the first rotation arm coupled to an engagement piece having at least one portion with a sloped perimeter, and the second rotation arm having a locking portion also having a sloped perimeter capable of receiving the at least one portion of the engagement piece the method also includes releasing the engagement piece from the locking portion by moving the first rotation arm to apply pressure against a spring mechanism, rotating at least one of the first and second rotation arms around a pivot piece, and locking the first and second rotation arms in a desired position by releasing pressure on the spring mechanism and engaging the engagement piece and the locking portion to prevent the first and second rotation arms from moving relative to each other.  
           [0008]    In another aspect of the present invention, a pivot joint includes a plate system having a first pair of joint plates, a first clutch plate, a second pair of joint plates, and a second clutch plate, the first and second clutch plates each having a grooved portion such that the first and second clutch plates are interlockable by engaging the grooved portions in each of the first and second clutch plates. The pivot joint also includes a spring mechanism positioned between the second clutch plate and one joint plate in the second pair of joint plates, and a pivot piece about which at least one joint plate in the first pair of joint plates and the first clutch plate are rotatable.  
           [0009]    In still another aspect of the present invention, a pivot joint includes a plate mechanism having a first clutch plate and a second clutch plate capable of lockably engaging, each of the first and second clutch plates having an elevated portion with a plurality of grooves and a plurality of bars therein such that when the elevated portions of each of the first and second clutch plates are aligned together, the plurality of bars of one of the first and second clutch plates lockably engage with the plurality of grooves of the other of the first and second clutch plate. The pivot joint also includes a release mechanism having a series of pins configured to disengage the first clutch plate from the second clutch plate when the series of pins pushes the second clutch plate against a spring mechanism.  
           [0010]    In yet another aspect of the present invention, a method of pivoting a joint apparatus includes providing a plate system including a first pair of joint plates, a first clutch plate, a second pair of joint plates, and a second clutch plate, the first and second clutch plates each having grooved portions such that the first and second clutch plates are securable by interlocking the grooved portions in each of the first and second clutch plates. The method also includes releasing the first and second clutch plates by activating a series of pins to push the second clutch plate against a spring mechanism, rotating at least one joint plate in the first pair of joint plates around a pivot piece, and locking the first and second clutch plates in a desired position by deactivating the series of pins to release pressure on the spring mechanism and engage the grooved portions on the first and second clutch plates to prevent the first and second clutch plates from moving relative to each other.  
           [0011]    In another aspect of the present invention, a method of pivoting a joint apparatus including providing a plate system having a pair of clutch plates each having grooved portions that allow the pair of clutch plates to interlock when interlocked together, releasing the pair clutch plates by activating a release mechanism to force the pair of clutch plates apart, rotating a first clutch plate in the pair of clutch plates about a pivot piece, and locking the pair of clutch plates in a desired position by deactivating the release mechanism allowing the grooved portions on the pair of clutch plates to engage each other and prevent the pair of clutch plates from moving relative to each other.  
           [0012]    It is understood that other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein it is shown and described only exemplary embodiments of the invention by way of illustration. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    Aspects of the present invention are illustrated by way of example, and not by way of limitation, in the accompanying drawings wherein:  
         [0014]    [0014]FIG. 1 is a perspective view of components of the pivot joint apparatus of the present invention;  
         [0015]    [0015]FIG. 2 is a more detailed perspective view of components of the pivot joint apparatus than that shown in FIG. 1;  
         [0016]    [0016]FIG. 3 is a close-up view of the particular components of the pivot joint apparatus;  
         [0017]    [0017]FIG. 4 is a side view of an engagement piece of the pivot joint apparatus;  
         [0018]    [0018]FIG. 5 is a top view of the engagement piece of the pivot joint apparatus;  
         [0019]    [0019]FIG. 6 is a top view of one rotation arm of the pivot joint apparatus;  
         [0020]    [0020]FIG. 7 is a perspective view of another rotation arm of the pivot joint apparatus;  
         [0021]    [0021]FIG. 8 is a top view of another rotation arm of the pivot joint apparatus;  
         [0022]    [0022]FIG. 9 is an enlarged perspective view of the pivot joint apparatus of the present invention;  
         [0023]    [0023]FIG. 10 is a perspective view of a release mechanism of the pivot joint apparatus;  
         [0024]    [0024]FIG. 11 is a diagrammatic view of locking components of the present invention;  
         [0025]    [0025]FIG. 12 is a cross-sectional view of a pivot joint apparatus according to one embodiment of the present invention;  
         [0026]    [0026]FIG. 13 is a perspective view of particular plate components of the pivot joint apparatus according to one embodiment of the present invention;  
         [0027]    [0027]FIG. 14 is a perspective view of the pivot joint apparatus according to one embodiment of the present invention;  
         [0028]    [0028]FIG. 15 is a side view of the pivot joint apparatus according to one embodiment of the present invention; and  
         [0029]    [0029]FIG. 16 is another side view of the pivot joint apparatus according to one embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0030]    The detailed description set forth below in connection with the appended drawings is intended as a description of exemplary embodiments in which the present invention can be practiced. The term “exemplary” used throughout this description means “serving as an example, instance, or illustration,” and should not necessarily be construed as preferred or advantageous over other embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.  
         [0031]    In an exemplary embodiment of the present invention, an adjustable pivot joint apparatus is provided having rotation components which, when separated, allow the apparatus to pivot about an axis. The apparatus also includes a release mechanism and a spring mechanism. The rotation components prevent the apparatus from pivoting about the axis when in a locked position.  
         [0032]    [0032]FIG. 1 is a perspective view of a pivot joint apparatus  100  according to the present invention. FIG. 2 is a more detailed perspective view of components of the pivot joint apparatus  100  than that shown in FIG. 1. The pivot joint apparatus  100  shown in FIG. 1 and FIG. 2 includes a rotation mechanism having a first rotation arm  102  and a second rotation arm  104 . The rotation mechanism also includes an engagement piece  106 . The first rotation arm  102  may be coupled to the engagement piece  106 . The second rotation arm  104  includes a locking portion  108  (not shown in FIG. 1 or FIG. 2) capable of receiving the engagement piece  106 . The locking portion  108  may be recessed within the second rotation arm  104 .  
         [0033]    The pivot joint apparatus  100  of the present invention may be used with any device, apparatus, or article of manufacture requiring an adjustable pivot joint. In one embodiment of the present invention, the pivot joint apparatus  100  is configured to have a range of adjustment of 180 degrees. One example of the use of a pivot joint apparatus  100  according to the present invention is in wheelchairs or strollers. Often, occupants of wheelchair or strollers must adjust the positioning of leg or arm rests or other components. This can be cumbersome for some occupants. Using the present invention, an occupant activates the release mechanism, adjusts the pivot joint apparatus and the component connected thereto to a desired position, and then deactivates the release mechanism. Additionally, the locking feature of the pivot joint apparatus  100  adds strength and durability to the pivot joint component of the wheelchair or stroller. It is noted that although various aspects of the present invention are described in the context of wheelchair and strollers, those skilled in the art will appreciate that the pivot joint apparatus  100  of the present invention is likewise suitable for use in various other mechanical environments. Accordingly, any reference to wheelchairs and strollers is intended only to illustrate the inventive aspects of the present invention, with the understanding that such inventive aspects have a wide range of applications.  
         [0034]    [0034]FIG. 1 and FIG. 2 also show a pivot piece  110 , a spring mechanism  112 , and a release mechanism  114  having a head portion  120 , a button  122 , and a series of pins  116 . The second rotation arm  104  includes a series of holes  118  which are capable of receiving the series of pins  116 . The pivot piece  110  extends centrally through the pivot joint apparatus  100  through the first rotation arm  102 , the spring mechanism  112 , the engagement piece  106 , the second rotation arm  104 , and the release mechanism  114 . The pivot piece  110  provides a point about which the rotation arms  102  and  104  of the pivot joint apparatus  100  rotate. The spring mechanism  112  may be a coil, which is wound around the pivot piece  100 , and positioned between the first rotation arm  102  and the engagement piece  106 .  
         [0035]    In one embodiment, each of the first and second rotation arms  102  and  104  includes a first end which is substantially circular. This first end is coupled to a substantially hollow member which houses components of the device to which the pivot joint apparatus  100  is attached. Within a first end  140  of the first rotation arm  102  is a recessed portion  132 , which is capable of receiving the second portion  128  of the engagement piece. Within a first end  142  of the second rotation arm  104  is the locking portion  108 , which is capable of receiving the first portion  124  of the engagement piece  106 . In another embodiment, the first ends  140  and  142  are adapted to receive each other when the first and second rotation arms  102  and  104  come together when the engagement piece  106  engages the locking portion  108 . In this embodiment, the first end  140  of the first rotation arm  102  includes a ridge  144  along a first edge  146 . The first end  142  of the second rotation arm  104  includes a gap  148  within a second edge  150 . The ridge  144  fits within the gap  148  when the first and second rotation arms  102  and  104  come together to provide a secure and tight closure for the pivot joint apparatus  100 .  
         [0036]    The engagement piece  106  includes first portion  124  and a second portion  128 . The first portion  124  includes a plurality of teeth  126 . The locking portion  108  of the second rotation arm  104  includes a plurality of grooves  130 . These plurality of grooves  130  are capable of receiving the plurality of teeth  126  in the first portion  124 . The first portion  124  may have an angled or sloped perimeter  162  along which the plurality of teeth  126  are aligned. The locking portion  108  may also have an angled or sloped perimeter  164  along which the plurality of grooves  130  are aligned for receiving the plurality of teeth  126  of the first portion  124 . FIGS. 1-4 and  11  show the angled, or sloped, perimeter  162  of the first portion  124 . FIG. 3 shows the angled or sloped perimeter  164  of the locking portion  108 . In one embodiment, the first portion  124  is conical in shape, and the second portion  128  is square in shape. The first rotation arm  102  includes a recessed portion  132  for receiving the second portion  128  of the engagement piece  106 .  
         [0037]    The first portion  124  and the second portion  128  of the engagement piece  106 , as well as other components of the pivot joint apparatus  100 , must be able to withstand significant wear and tear over a long period of time and in a variety of weather conditions. In one embodiment, plastic and nylon are materials used to manufacture various components in the pivot joint apparatus  100 , such as the engagement piece  106 . It is noted that any other materials that are capable of withstanding repeated use in both severe cold and severe heat may also be used to manufacture components of the pivot joint apparatus  100 .  
         [0038]    [0038]FIG. 3 is a close-up view of the particular components of the pivot joint apparatus  100 , showing the second rotation arm  104  and the engagement piece  106 . FIG. 3 shows the plurality of grooves  130  in the locking portion  108  of the second rotation arm  104  that are capable of receiving the plurality of teeth  126  of the first portion  124  of the engagement piece  106 . FIG. 3 also shows the second portion  128  of the engagement piece  106 . FIG. 4 is a close-up side view of the engagement piece  106  of the pivot joint apparatus  100 . FIG. 4 shows the engagement piece  106  with the first portion  124  and the second portion  128 . FIG. 5 is a close-up top view of the engagement piece  106  of the pivot joint apparatus  100 , showing the second portion  128  having a substantially square shape. The first portion  124  includes the plurality of teeth  126  in FIG. 5.  
         [0039]    The plurality of teeth  126  in the first portion  124  of the engagement piece  106  are adapted to fit into the plurality of grooves  130  in the locking portion  108 . The use of the teeth and grooves design allows for stress on the contact portions of the pivot joint to be distributed over a large surface area, strengthening the overall performance of the locking mechanism and reducing the possibility of failure of the pivot joint apparatus  100 . In the embodiment where the first portion  124  has a substantially conical shape, the locking portion  108  also has a substantial conical shape to receive the first portion  124 . The conical configuration of the first portion  124  and the locking portion  108  allows for greater penetration of the locking element, increased surface engagement of the locking element, and redirection and reduction of the force opposing the spring mechanism  112 . In another embodiment, the first portion  124 , the plurality of teeth  126 , the locking portion  108 , and the plurality of grooves  130  all are substantially sloped with an angle of 45°.  
         [0040]    [0040]FIG. 6 is a top view of the second rotation arm  104  of the pivot joint apparatus  100 . The second rotation arm  104  as shown in FIG. 6 includes the locking portion  108 , which in one embodiment may be recessed within the second rotation arm  104 . The locking portion  108  shown in FIG. 6 includes the plurality of grooves  130 . FIG. 6 also shows a series of holes  118  in the locking portion  108  and the second rotation arm  104 , through which the series of pins  116  may be positioned. FIG. 6 also shows that the locking portion  108  and the second rotation arm  104  include a pivot piece hole  134  through which the pivot piece  110  extends. The pivot piece hole  134  may be centrally positioned in the locking portion  108  and the second rotation arm  104  and may extend all the way through the pivot joint apparatus  100 .  
         [0041]    [0041]FIG. 7 is a perspective view of the first rotation arm  102  of the pivot joint apparatus  100 . FIG. 7 shows the first rotation arm  102  having a recessed portion  132 , into which the second portion  128  of the engagement piece  106  may be positioned. In one embodiment, the second portion  128  is substantially square in shape. In this embodiment, the recessed portion  132  in the first rotation arm  102  is also substantially square in shape to receive the second portion  128  of the engagement piece  106 . FIG. 8 is a top view of the first rotation arm  102  of the pivot joint apparatus  100 , also showing the recessed portion  132  into which the second portion  128  of the engagement piece  106  can be positioned.  
         [0042]    The second portion  128  and the recessed portion  132  provide additional security for the pivot joint apparatus  100 . The first rotation arm  102  engages with the second portion  128  of the engagement piece  106  to prevent rotation of the first rotation arm  102 , and also to prevent rotation of the engagement piece  106  relative to the first rotation arm  102 . The second portion  128  and the recessed portion  132  may be of any shape that prevents the first rotation arm  102  and the engagement piece  106  from moving relative to each other.  
         [0043]    [0043]FIG. 9 is an enlarged perspective view of the pivot joint apparatus of the present invention. FIG. 9 shows the first rotation arm  102 , the second rotation arm  104 , and the release mechanism  114 , including the head portion  120  and the button  122 . The button  122  may be positioned centrally relative to the head portion  120 .  
         [0044]    [0044]FIG. 10 is a perspective view of a release mechanism  114  of the pivot joint apparatus  100 . FIG. 10 shows the head portion  120  of the release mechanism  114 , the button  122 , and the series of pins  116 . The series of pins  116  extend downward from the release mechanism  114  and the head portion  120 . In one embodiment, the series of pins  116  may be curved. The series of pins  116  may also be contoured, such that one side  136  of a pin in the series of pins  116  is shaped to form a ridge  138 . This contour allows the series of pins  116  to securely fit into the series of holes  118 , such as by snapping into place. The contour shaping of the pins allows the series of pins  116  to fit into the series of holes  118  and prevent the pivot joint apparatus  100  from disengaging when in an locked position.  
         [0045]    When the pivot joint apparatus  100  is locked, the spring mechanism  112  is in a substantially uncompressed state so that it biases the engagement piece  106  into the locking portion  108  of the second rotation arm  104 . This provides additional security to keep the engagement piece  106 , and the pivot joint apparatus  100 , locked in a desired position. When the button  122  on the head portion  120  of the release mechanism  114  is pressed, the series of pins  116  are forced further through the series of holes  118 . The series of pins  116  contact a side of the first portion  124  of the engagement piece  106  and cause the spring mechanism  112  to compress, allowing the first portion  124  to be pushed out of the locking portion  108 , and disengaging the plurality of teeth  126  from the plurality of grooves  130 . The compressing spring mechanism  112  pushes against the recessed portion  132  of the first rotation arm  102 , separating the ridge  144  from the gap  148  in the second rotation arm  104  and moving the first rotation arm  102  clear of the second rotation arm  104 . Full pressure on the button  122  therefore separates the engagement piece  106  from the second rotation arm  104 . Because the second portion  128  of the engagement piece  106  fits within the recessed portion  132  of the first rotation arm  102 , and because the shape of the recessed portion  132  and the second portion  128  allow the engagement piece  106  and the first rotation arm  102  to move together, the first rotation arm  102  and the engagement piece  106  are rotatable relative to the second rotation arm  104  about the pivot piece  110  to adjust the configuration of the pivot joint apparatus  100 . The spring mechanism  112  therefore compresses enough to allow the second portion  128  to fit securely within the recessed portion  132  of the first rotation arm  102 . When a user has adjusted the angle of the first rotation arm  102  relative to the second rotation arm  104  to his or her liking, pressure can be released on the button  122  to return the first portion  124  of the engagement piece  106  so that the plurality of teeth  126  once again fit within the plurality of grooves  130  in the second rotation arm  104  and so that the ridge  144  of the first rotation arm  102  fits within the gap  148  in the second rotation arm  104  to securely hold the pivot joint apparatus  100  at the desired setting. The release of pressure on the button  122  therefore causes the spring mechanism  112  to decompress and bias the engagement piece  106  in the locking portion  108 , thereby returning the pivot joint apparatus  100  to a locked position.  
         [0046]    Other embodiments for release mechanisms are also contemplated for use in the present invention. In one embodiment, any number of pins may be used to release the engagement piece  106 . In another embodiment, the first and second rotation arms  102  and  104  may include levers or switches which, when pressed or activated, cause the first portion  124  to separate from the locking portion  108 . In yet another embodiment, activation mechanisms, such as additional push buttons, may be positioned on the first and second rotation arms  102  and  104  to activate the release mechanism  114  extend the series of pins  116 . It is noted that any method of causing the release or separation of the first portion  124  of the engagement piece  106  from the locking portion  108  of the second rotation arm  104  is contemplated for use with the present invention.  
         [0047]    [0047]FIG. 11 is a diagrammatic view of particular components of the locking mechanism according to one embodiment of the present invention, showing the first portion  124  of the engagement piece  106  inserting into the locking portion  108  of the second rotation arm  104 . In this embodiment, the first portion  124  has a substantially sloped perimeter, and the plurality of teeth  126  along the perimeter are also substantially sloped. The locking portion  108  is also shown to be substantially sloped, to accept the substantially sloped perimeter of the first portion  124 . One example of an angle of slope is a 45° angle. In another embodiment, the substantially sloped perimeter of the first portion  124  and the plurality of teeth  126  are conical in shape, and the locking portion  108  is also conical in shape to accept the first portion  124 . The conical shape may also employ a 45° angle of slope.  
         [0048]    An axial configuration, instead of a sloped or conical configuration, produces a reactive force perpendicular to the plane of engagement. In this type of configuration, the locking components want to disengage due to the reactive forces acting on the pivot joint. A radial configuration, instead of a sloped of conical configuration, produces a reactive force parallel to the plane of engagement. In this type of configuration, the locking components tend to slip over time and damage the teeth as the components become worn.  
         [0049]    In the embodiment of FIG. 11, the reactive force  152 , or the force trying to disengage or ride over the plurality of teeth, is split by the 45° angle into 50% axial and 50% radial forces, shown by reference numbers  154  and  156 , respectively, thus lessening the disengaging effect of the reactive force on the pivot joint. The 45° angle also allows for longer teeth in the plurality of teeth with a greater amount of surface contact  158 . This lessens the load per unit of area of contact surface. In addition, the angled entry of engagement of the teeth results in a greater depth of engagement  160  without increasing the height of the profile of the teeth. Further, the sloped or conical configuration allows the pivot joint to be self-aligning after wear.  
         [0050]    In another embodiment of the present invention, an adjustable pivot joint apparatus is provided having a plate system which includes interlocking clutch plates which, when separated, allow the apparatus to pivot about an axis. The apparatus also includes a release mechanism and a spring mechanism. The clutch plates prevent the apparatus from pivoting about the axis when in a locked position.  
         [0051]    [0051]FIG. 12 is a cross-sectional view of a pivot joint apparatus  100  according to the present invention. The pivot joint apparatus  100  of FIG. 12 is shown in an unlocked position. The pivot joint apparatus  100  includes a system of plates. The system of plates includes a first pair of joint plates  200  and a second pair of joint plates  202 . The system of plates also includes a first clutch plate  204  and a second clutch plate  206 . The first clutch plate  204  may be coupled to the first pair of joint plates  200 . The first and second clutch plates  204  and  206  may be substantially circular in shape. The first and second clutch plates  204  and  206  may be made of sheet metal or any other material of suitable strength.  
         [0052]    In one embodiment, each of the first and second clutch plates  204  and  206  may include an elevated portion  208 . The elevated portion  208  includes a series of grooves  210  and bars  212  between the series of grooves  210 . Each of the first and second clutch plates  204  and  206  also include a central portion  214  which may have a series of holes  216  positioned therein.  
         [0053]    The first and second clutch plates  204  and  206  may be positioned such that the elevated portions  208  face each other. The bars  212  in the elevated portion  208  of one clutch plate fit into the series of grooves  210  of the elevated portion  208  of the other clutch plate. When the elevated portions  208  fit together, this results in the first and second clutch plates  204  and  206  being in an interlocked, secure position relative to each other, such that neither of the first or second clutch plates  204  and  206  can move laterally until the bars  212  are disengaged from the series of grooves  210 .  
         [0054]    The first and second clutch plates  204  and  206  may include any number of grooves  210  and bars  212  in their elevated portions  208 . Additionally, the grooves  210  and bars  212  may be flat with respect to the other components of the first and second clutch plates  204  and  206 , or may be depressed within the first and second clutch plates  204  and  206 . Other embodiments for interlocking the first and second clutch plates are also contemplated in the present invention. For example, a gear system may be used to interlock the first and second clutch plates to prevent their movement relative to each other. It is noted that any means of providing interlocking mechanical components can be used with the present invention to achieve a locking system that prevents one or more components from moving.  
         [0055]    The pivot joint apparatus  100  also includes a pivot piece  218  positioned in one of the joint plates in the first pair of joint plates  200 . The pivot joint apparatus  100  also includes a release mechanism. In one embodiment, the release mechanism has a series of pins  220  housed in a head portion  222 . The series of pins  220  penetrate the first pair of joint plates  200 , the pivot piece  218 , and the first clutch plate  204 . The series of pins  220  also contact with the second clutch plate  206  and, when activated by exerting pressure on the head portion  222 , cause the second clutch plate  206  to move away from the first clutch plate  204  as described in greater detail below. The head portion  222  may also include a post  224  and a closure cap  226 . Each of the first and second clutch plates  204  and  206  include a post hole  234  through which the post  224  passes.  
         [0056]    The head portion  222  may also include a housing  238  within which the series of pins  220  and the post  224  are positioned. In one embodiment, the series of pins  220  are activated by pressing or pushing the head portion  222  to force the series of pins  220  to extend down to exert force on the second clutch plate  206 . In another embodiment, the closure cap  226  acts as a button which can be pushed to activate the series of pins  220  and force them to extend down to exert force on the second clutch plate  206 . In yet another embodiment, activation mechanisms, such as push buttons, may be positioned on the pairs of joint plates  200  or  202  to activate and extend the series of pins  220 .  
         [0057]    Other embodiments for release mechanisms are also contemplated for use in the present invention. In one embodiment, any number of pins may be used to release the first and second clutch plates. In another embodiment, the joint plates  200  and  202  may include levers or switches which, when pressed or activated, cause the first and second clutch plates to separate. It is noted that any method of causing the release or separation of the first and second clutch plates is contemplated for use with the present invention.  
         [0058]    Each joint plate in the first pair of joint plates  200  may be coupled together by the post  224  and the series of pins  220 . Each joint plate in the second pair of joint plates  202  may also be coupled together by the post  224 .  
         [0059]    The pivot piece  218  provides a large, non-rotating diameter about which the pivot joint apparatus  100  can be adjusted. In one embodiment, the pivot piece  218  is a washer positioned adjacent to the central portion  214  of the first clutch plate  204 . When the first and second clutch plates  204  and  206  are disengaged, the pivot joint apparatus  100  is adjustable by rotating joint plates in the first and second joint plates  200  and  202  about the pivot piece  218 .  
         [0060]    The pivot joint apparatus  100  may also include a spring mechanism  228 . The second clutch plate  206  includes a first extension  230 . One of the joint plates in the second pair of joint plates  202  includes a second extension  232  which is capable of insertion into the first extension  230 . The spring mechanism  228  may be a coil wound around the first extension  230  and the second extension  232 . The post  224  extends all the way through from the head portion  222  to the second pair of joint plates  202 , as shown in FIG. 12.  
         [0061]    [0061]FIG. 13 is a perspective view of a portion of the system of plates of the pivot joint apparatus  100 . The first pair of joint plates  200  and the first clutch plate  204  are shown, with a portion of the first clutch plate  204  removed to show the pivot piece  218 . The series of holes  216  through which the series of pins  220  pass extend through the first pair of joint plates  200 , the pivot piece  218 , and the first clutch plate  204 .  
         [0062]    [0062]FIG. 14 is a perspective view of the pivot joint apparatus  100  according to the present invention, showing the various components in separated fashion. The pivot joint apparatus  100  may be used with any device or article of manufacture requiring an adjustable pivot joint. FIG. 14 shows members  236  which are securable to the pivot joint apparatus  100 . The position of the members  236  can be adjusted by rotating at least one joint plate in each of the first and second pairs of joint plates  200  and  202  together about the pivot piece when the first and second clutch plates  204  and  206  are separated. One example of the use of a pivot joint apparatus  100  according to the present invention is in wheelchairs or strollers. Often, occupants of wheelchair or strollers must adjust the positioning of leg or arm rests or other components. This can be cumbersome for some occupants. Using the present invention, an occupant activates the release mechanism, adjusts the pivot joint apparatus and the component connected thereto to a desired position, and then deactivates the release mechanism. Additionally, the clutch plate locking feature adds strength and durability to the pivot joint component of the wheelchair or stroller. Accordingly, the members  236  are portions of a mechanical component to which the pivot joint apparatus is connected. The members  236  are provided to show a particular use for the pivot joint apparatus of the present invention. It is noted that although various aspects of the present invention are described in the context of wheelchair and strollers, those skilled in the art will appreciate that the pivot joint apparatus of the present invention is likewise suitable for use in various other mechanical environments. Accordingly, any reference to wheelchairs and strollers is intended only to illustrate the inventive aspects of the present invention, with the understanding that such inventive aspects have a wide range of applications.  
         [0063]    [0063]FIG. 15 is a side view of the pivot joint apparatus  100 . The pivot joint apparatus  100  of FIG. 15 is in an unlocked position and ready for adjustment. To unlock, or disengage, the first and second clutch plates  204  and  206 , the release mechanism is activated to force the series of pins  220  to extend and push the second clutch plate  206  away from the first clutch plate  204 . This results in the bars  212  and the series of grooves  210  being disengaged from each other, allowing lateral movement of the first clutch plate  204  relative to the second clutch plate  206 . Once the first and second clutch plates  204  and  206  have been disengaged, at least one of the joint plates in the first pair of joint plates  200  can be rotated, in conjunction with at least one joint plate from the second pair of joint plates  202 , about the pivot piece  218 .  
         [0064]    When the series of pins  220  pushes the second clutch plate  206  away from the first clutch plate  204 , the second clutch plate  206  pushes against the spring mechanism  228 . When not pushed down by the second clutch plate  206  and the series of pins  220 , the spring mechanism  228  also serves to bias the second clutch plate  206  against the first clutch plate  204  to provide further stability for the system of plates when the bars  212  and the series of grooves  210  of the first and second clutch plates  204  and  206  are engaged.  
         [0065]    [0065]FIG. 16 is another side view of the pivot joint apparatus  100 . The pivot joint apparatus  100  of FIG. 16 is in a locked position such that the plates making up the system of plates do not move. In FIG. 16, the first and second clutch plates  204  and  206  are engaged in a locked position, preventing the system of plates, and therefore the pivot joint apparatus itself, from moving. Additionally, the spring mechanism  228  biases the second clutch plate  206  against the first clutch plate  204 .  
         [0066]    The preceding description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.