Abstract:
A wheel clamping assembly provides a frame having three arms, two fixed stops and a turnable cam. The arms are equally spaced and have holes to admit the stops and the cam. The stops have an extension eccentrically located upon the top of the cylinder. Then the cam has an involute, having an expanding radius, upon the top of the cam. In use, the stops are placed upon two arms and the cam is placed upon the remaining arm, all at the same radius. A wheel rim is positioned upon the stops and the cam. The cam is then turned to grasp the wheel. The stops and the cam are made of a non-marring material.

Description:
BACKGROUND OF THE INVENTION 
   The wheel clamping assembly relates generally to tire changing machinery and more specifically to a frame to clamp a wheel. 
   In bays and shops across the land, tires are changed from wheels in large numbers everyday. Tires have sidewalls upon both sides of the tire that extend partially towards the center. At the innermost portion of the sidewall, the tire has an encased bead. The bead is a thickened portion of the sidewall surrounding metal wire. Now a wheel generally has two parallel rims upon the circumference of both sides of the wheel. The rims have a greater diameter than the substantial portion of the circumference. 
   Tire changing involves mounting a tire upon a wheel or removing a tire from a wheel. For mounting a tire upon a wheel, the wheel is clamped into a fixed position. One bead is placed over a rim as much as possible and then mechanical means stretch the remainder of the bead over the rim. The second bead undergoes the same procedure. Inflating the tire then seats both beads against their respective rims. For removing a tire from a wheel, the wheel is clamped again into a fixed position. The tire is partially deflated and then mechanical means is inserted between a bead and a rim. The mechanical means stretches a small portion of the bead over the rim. Continuing to operate, the mechanical means then lifts the remainder of the bead over the rim. As before, the second bead undergoes the same demounting procedure. 
   Wheels are used on many vehicles. On utility vehicles, the appearance of wheels matters less so than on personal vehicles. For automobiles, motorcycles, and some boat trailers, the wheels and their appearance have high importance to their drivers. People often place great emphasis on the appearance of wheels as part of their self image. The after market in wheels of all kinds has enormous size. Often, people seek out shiny or novelty wheels to separate vehicles. In particular, motorcycles have shiny wheels including spokes and rims. 
   DESCRIPTION OF THE PRIOR ART 
   Traditionally, wheels, even shiny wheels, have been clamped for tire changing and other procedures. In a typical prior art frame, a wheel is placed upon a three armed frame and a shaft descends to and often through the hub of the wheel. Then one or more heavy steel jaws advance and grasp the rim of a wheel. The heavy jaws often mar the rim of a wheel. 
   In particular, an existing motorcycle tire changer has a three armed frame with steel jaws to grasp a wheel. The three arms have an equiangular arrangement and a jaw pivotally mounts upon each arm. Each jaw has two upright sides with an edge to grasp the rim. The two sides allow each jaw to grasp a round rim tightly. Generally, the jaws have a U shaped cross section of varying height. The jaws upon two arms are positioned at fixed intervals along the arms. The jaw upon the third arm can be adjustably positioned using a hand crank. The hand crank turns a threaded shaft connected to the jaw. The jaw on the third arm then locks the wheel upon the frame. 
   The prior art has many frames and devices to clamp wheels. However, the prior art shares the common disadvantage of marring the rim of a wheel. The jaws of the existing tire changer contact a wheel at six points and depending on wheel hardness will mar the wheel at each point. Marring leads to discoloration, rust, and an unsightly appearance. For drivers and cyclists sensitive to the appearance of their wheels, marring is not acceptable. 
   The present invention overcomes the difficulties of marring a wheel during clamping. 
   SUMMARY OF THE INVENTION 
   Generally, the present invention provides a frame having three arms, two fixed stops upon two arms, and a turnable cam. The arms have an equi-angular orientation and a pattern of holes to admit the stops and the cam. The stops have a pin, a cylinder centered upon the pin, and an extension eccentrically located upon the top of the cylinder. Then the cam has a pin, a cylinder centered upon the pin, and an involute upon the top of the cam. In use, the stops are placed upon two arms at the same radius from the center of the frame and the cam is placed upon the remaining arm at the same radius. A wheel rim is placed upon the stops and the cam. The cam is then turned to grasp the wheel. The stops and the cam are made of a non-marring material. 
   There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and that the present contribution to the art may be better appreciated. The present invention also includes ears upon the bottom of the stops, extensions having four curved edges, and a handle upon the cam. The extensions and the involute also have inward beveled edges to grasp the rim of a wheel. Additional features of the invention will be described hereinafter and which will form the subject matter of the claims attached. 
   Numerous objects, features and advantages of the present invention will be readily apparent to those of ordinary skill in the art upon a reading of the following detailed description of the presently preferred, but nonetheless illustrative, embodiment of the present invention when taken in conjunction with the accompanying drawings. Before explaining the current embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
   One object of the present invention is to provide a new and improved wheel clamping assembly. 
   Another object is to provide such a wheel clamping assembly that has clamps that engage a wheel firmly but without marring the wheel. 
   Another object is to provide such a wheel clamping assembly that is portable. 
   Another object is to provide such a wheel clamping assembly that has edges upon the stops and cam to lower the risk of injury to people. 
   These together with other objects of the invention, along with the various features of novelty that characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated a preferred embodiment of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows an oblique view of a wheel located upon the frame, stops, and cams constructed in accordance with the principles of the present invention; 
       FIG. 2  shows an isometric view of the present invention; 
       FIG. 3   a  shows a side view of a stop of the present invention; 
       FIG. 3   b  shows a top view of a stop of the present invention; 
       FIG. 3   c  shows a bottom view of a stop of the present invention; 
       FIG. 4   a  shows a side view of the cam of the present invention; 
       FIG. 4   b  shows a top view of the cam of the present invention; 
       FIG. 4   c  shows a bottom view of the cam of the present invention; and, 
       FIG. 5  describes an alternate embodiment of the fixing means. 
   

   The same reference numerals refer to the same parts throughout the various figures. 
   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present art overcomes the prior art limitations by providing stops and a cam upon a frame that grasp a wheel without marring. Beginning on  FIG. 1 , a wheel  3  clamping assembly  1  has three arms  5  generally in a Y shape and more specifically arranged equi-angular. Each arm  5  has a top surface  5   a  and a pattern of holes along the top surface  5   a  of the arms  5 . Upon two of the arms  5 , a stop  6  is placed. Each stop  6  has notches  13  upon the bottom surface  6   b  so the stop  6  rests upon the top surface  5   a  of an arm  5  and resists rotation. In the preferred embodiment, the stop  6  has four notches  13  symmetrically arranged upon the bottom surface  6   b . The notches  13  have a width that snugly fits the arms  5 . Upon the top surface  6   a  of each stop  6 , each stop  6  has an extension  6   c . The extension  6   c  has an inward bevel  11  where the uppermost portion of the extension  6   c  is wider than the lowest portion of the extension  6   c  in contact with the top surface  6   a  of the stop  6 . The inward bevel  11  allows the extension  6   c  of the stop  6  to grasp the rim  2  of a wheel  3 . 
   Upon the third arm  5 , a cam  7  is placed. The cam  7  has a generally flat bottom surface  7   b  that rests upon the top surface  5   a  of the third arm  5 . Opposite the bottom surface  7   b , the cam  7  has an involute  7   c . As in the stops  6 , the involute  7   c  has an inward bevel  11  to grasp the rim  2  of a wheel  3 . The involute  7   c  begins with a first radius  15   a  approximately ½ inch from the edge of the cam  7 . The involute  7   c  then has the radius lengthen around the perimeter of the involute  7   c  at a regular rate. The second radius  15   b  extends to approximately ¼ inch from the edge of the cam  7  proximate to the first radius  15   a . The cam  7  has a handle  14  extending perpendicular to the cam  7  at generally half the height of the cam  7 . The handle  14  is approximately one eighth turn behind the second radius  15   b.    
     FIG. 1  shows a wheel  3  placed upon the present invention  1 . The stops  6  are positioned with the extension  6   c  turned closest to the rim  2  of the wheel  3 . The stops  6  occupy a hole to accommodate the radius of the wheel  3 . The cam  7  is positioned upon the third arm  5  within reach of an operator. The involute  7   c  grasps the rim  2  of the wheel  3 . As the operator turns the handle  14  towards the wheel  3 , the involute  7   c  grasps the rim  2  tighter. When the involute  7   c  binds upon the wheel  3 , the rim  2  is secure for tire changing using conventional methods, not shown. In the preferred embodiment, the stops  6  and the cam  7  are made of a polymer material that has lesser hardness than the rim  2  and thus does not mar metal rims  2  of wheels  3 . 
     FIG. 2  shows the present invention  1  without an installed wheel  3 . The present invention  1  has three arms  5  generally in a Y shape and equi-angular. The arms  5  are slender where the length markedly exceeds the width of an arm  5 . Each arm  5  has a top surface  5   a  and a pattern of holes along the top surface  5   a . The holes indicate common diameters of wheels  3  likely to be used upon the present invention  1 . Upon two of the arms  5 , a stop  6  is placed. Each stop  6  has notches  13  upon the bottom surface  6   b  so the stop  6  resists rotation. Preferably, the stop  6  has four notches  13  symmetrically arranged. Opposite the notches  13 , each stop  6  has an extension  6   c  with an inward bevel  11  to grasp the rim  2  of a wheel  3 . Upon the third arm  5 , a cam  7  is placed upon the top surface  5   a . The cam  7  has an involute  7   c , also with an inward bevel  11  to grasp the rim  2  of a wheel  3 . The involute  7   c  begins with a first radius  15   a , expands the radius around the perimeter of the involute  7   c , and ends at a second radius  15   b  near to the position of the first radius  15   a . The handle  14  identifies the cam  7  and allows an operator to turn the cam  7  and secure a wheel  3  within the cam  7  and the stops  6  for tire changing. 
   More particularly,  FIG. 3A  shows a side view of a stop  6 . The stop  6  has a generally round cylindrical shape with a top surface  6   a  and an opposite bottom surface  6   b  joined by a perimeter side. Upon the top surface  6   a , each stop  6  has an extension  6   c . The extension  6   c  is located off center and has three or more edges. In the preferred embodiment, the extension  6   c  has four edges  10  with a first edge  10   a  as a chord located approximately ¼ inch from the perimeter of the stop  6  here shown towards the left of the figure. As described previously, each edge has an inward bevel  11  where the uppermost surface of the extension  6   c  overhangs the joint of the extension  6   c  to the top surface  6   a  of the stop  6 . The inward bevel  11  grasps the rounded surface of the rim  2  of a wheel  3 . 
   Opposite the extension  6   c  and the top surface  6   a , the stop  6 , on its bottom surface  6   b , has a means to fix  9  the stop  6  from rotation upon an arm  5 . In the preferred embodiment, the bottom surface  6   b  has four ears  12  integral with the stop  6  and descending from the bottom surface  6   b  defining four notches  13 . The four ears  12  define the fixing means  9 . The notches  13  generally have the width of an arm  5  for a snug fit with minimal rotation of the stop  6  under load. Generally centered upon and depending from the bottom surface  6   b , a pin  8  connects the stop  6  to an arm  5 . In the preferred embodiment, the pin  8  is a solid steel cylinder that extends beneath the ears  12 . The pin  8  has the same diameter as the holes in the arm  5  for a snug fit at a chosen diameter upon the frame  4 . At the bottom surface  6   b , the pin  8  has a circumferential groove  8   a  of slightly less diameter than the pin  8 . The groove  8   a  grips the top surface  5   a  of the arm  5  snugly. Alternatively as later shown in  FIG. 5 , the fixing means is four pegs  16  inserted into the bottom surface  6   b . The pegs  16  are generally cylindrical in shape and positioned to prevent rotation of the stop  6 . 
     FIG. 3B  shows the top of a stop  6  and more particularly the extension  6   c . The extension  6   c  is generally rectangular in shape and allows for four adjustments in grasping a wheel  3  when the stop  6  is at a chosen diameter indicated upon an arm  5 . As described before, the preferred embodiment of the extension  6   c  has four edges  10  with the first edge  10   a  being a chord approximately ¼ inch from the perimeter of the top surface  5   a . The first edge  10   a  of the extension  6   c  is nearest of all the edges towards the perimeter. Then the second edge  10   b  is a chord perpendicular to the first edge  10   a  and located approximately ½ inch from the circumference of the cam  7 . The third edge  10   c  is also a chord parallel to the first edge  10   a  but located approximately one inch from the perimeter of the top surface  6   a . And the fourth edge  11  is also a chord parallel to the second edge  10   b  but located approximately 1.25 inches from the perimeter. 
   On the other surface,  FIG. 3C  shows the bottom surface  6   b  of a stop  6 . In the preferred embodiment, the bottom surface  6   b  has four ears  12  descending from the bottom surface  6   b  defining four notches  13 . The four ears  12  and their respective notches  13  are symmetrically arranged along two axes of symmetry. The ears  12  have a rounded triangular shape with the hypotenuse of each ear 12 partially along the perimeter of the stop  6 . The notches  13  generally have the width of an arm  5  for a snug fit. Generally centered upon the bottom surface  6   b , the pin  8  extends outward from the stop  6  beyond and beneath the ears  12 , and connects to an arm  5 . And, the pin  8  has the same diameter as the holes in the arm  5  for a snug fit. Further, the pin  8  has a groove  8   a  around the circumference proximate to the stop  6  for grasping temporarily the top surface  5   a  of an arm  5  as previously shown in  FIG. 3A . 
   Looking at the third securement for a wheel  3 ,  FIG. 4A  shows a side view of the cam  7 . The cam  7  has a generally round cylindrical shape with a top surface  7   a  and an opposite bottom surface  7   b  joined by a perimeter side. Upon the top surface  7   a , each cam  7  has an involute  7   c . The involute  7   c  is located off center and has an initial radius ending approximately ½ inch from the perimeter of the cam  7 . The radius then expands clockwise around the involute  7   c . Generally near  12  the initial or first radius  15   a , the involute  7   c  has a final or second radius  15   b  ending approximately ¼ inch from the perimeter of the cam  7 . As described previously, the edge of the involute  7   c  has an inward bevel  11  where the uppermost surface of the involute  7   c  overhangs the joint of the involute  7   c  to the top surface  7   a  of the cam  7 . The inward bevel  11  secures the rounded surface of the rim  2  of a wheel  3 . 
   Opposite the involute  7   c  and the top surface  7   a , the cam  7  has a flat bottom surface  7   b  that rests upon an arm  5  and allows the cam  7  to turn upon the arm  5 . Generally centered upon and depend 5bing from the bottom surface  7   b , a pin  8  connects the cam  7  to an arm  5 . In the preferred embodiment, the pin  8  is a solid steel cylinder that extends beneath the ears  12 . The pin  8  has the same diameter as the holes in the arm  5  for a snug fit at a chosen diameter upon the frame  4 . At the bottom surface  7   b , the pin  8  has a circumferential groove  8   a  of slightly less diameter than the pin  8 . The groove  8   a  seats the cam  7  in the holes and upon the top surface  5   a  of the arm  5  snugly. 
   Extending from the perimeter side of the cam  7 , a handle  14  permits an operator to turn the cam  7 . The handle  14  is perpendicular to the cam  7  generally centered upon the height of the cam  7 . Turning the cam  7  brings the involute  7   c  closer towards the rim  2  of a wheel  3 , thus securing the wheel  3  to the frame  4 . 
     FIG. 4B  shows the top of the cam  7  and more particularly the involute  7   c . The involute  7   c  is somewhat round in shape, more particularly nautilus like and similar to an arc formed as a line is extended under constant tension, and allows for adjusting the distance between the involute  7   c  and a rim  2  between two limits. As described before, the preferred embodiment of the involute  7   c  has an initial radius  15   a  and a final radius  15   b  with the final radius  15   a  exceeding the initial radius  15   b  by approximately ¼ inch. The final radius  15   a  locates the involute  7   c  closest to the perimeter of the cam  7 . Viewing the top, the handle  14  extends from the cam  7 , generally one eighth turn behind the final radius. 
   Opposite the top of the cam  7 ,  FIG. 4C  shows the bottom surface  7   b . In the preferred embodiment, the bottom surface  7   b  is flat. Then generally centered upon the bottom surface  7   b , a pin  8  extends outward from the cam  7  beyond and perpendicular to the bottom surface  7   b . As in the stop  6 , the pin  8  in the cam  7  has the same diameter as the holes in the arm  5  for a snug fit. Further, the pin  8  has a groove  8   a  around the circumference proximate to the cam  7  for grasping temporarily the top surface  5   a  of an arm  5  as previously shown in  FIG. 4A . Alternatively, the handle  14  has a grip  14   a  applied to assist an operator in turning the cam  7 . 
   From the aforementioned description, a wheel clamping assembly has been described. The wheel clamping assembly is uniquely capable of clamping wheels without marring them. The wheel clamping assembly and its various components may be manufactured from many materials, including but not limited to, polymers, polyvinyl chloride, high density polyethylene, polypropylene, nylon, ferrous and non-ferrous metals, their alloys, and composites. 
   As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. Therefore, the claims include such equivalent constructions insofar as they do not depart from the spirit and the scope of the present invention.