Abstract:
An apparatus and method for making possible an infinite variation in the adjustment angle of a spindle assembly makes possible a rapid changeover for testing the dynamic properties of elastomeric objects. In spindle assembly ( 10 ), wedge rings ( 18, 20 ) having wider portions ( 22, 22   a ) and narrower portions ( 24, 24   a ) interposed between a spindle ( 12 ) and an axle assembly ( 17 ), whereby the relative placement of the wider portions ( 22, 22   a ) and the narrower portions ( 24, 24   a ) determine the angle of the spindle ( 12 ) relative to axle assembly ( 17 ). Indicia ( 48, 48   a ) on the wedge rings ( 18, 20 ) make possible quick determination of the exact angle. Means ( 50, 50   a   , 67 ) may be provided to make easier rotation of the wedge rings ( 18, 20 ).

Description:
TECHNICAL FIELD 
     The invention relates to an adjustable spindle for rotating round elastomeric objects. Specifically, the invention relates to changing the camber angle of a spindle used for rotating tires. 
     BACKGROUND ART 
     In the automotive industry, some manufacturers design their vehicles having a suspension which provides a camber to the wheels that are used on the vehicle. When developing tires for such vehicles, it is important to test an experimental tire under conditions very similar to those encountered on a vehicle. Accordingly, spindles used for spinning tires on test equipment have been adapted to provide camber to a tire during dynamic testing. 
     In prior art testing equipment, however, spindles providing a camber were not adjustable and could be set up only at one angle. Conversion to a different angle was possible but involved dismantling the equipment to change the angle. Even then, only a limited number of angles were possible. 
     Vehicle manufacturers often experiment with different camber angles on vehicles, and a large variety of vehicles are being manufactured with camber angle on the suspension systems, and it is important that tires be tested at the large number of camber angles which are used, or are considered experimentally. 
     It is an object of the present invention to provide an adjustable spindle which makes possible the quick adjustment of the camber angle of the spindle. 
     SUMMARY OF THE INVENTION 
     A spindle assembly ( 10 ) for rotating round objects comprises a spindle ( 12 ) and a spindle plate ( 14 ) attached to a back plate ( 16 ), the spindle plate ( 14 ) and back plate ( 16 ) having interposed there between at least two wedge rings ( 18 , 20 ), wedge rings( 18 , 20 ) having a wider portion ( 22 , 22   a ) and a narrower portion ( 24 , 24   a ). In the assembly, when a narrower portion ( 24 ) of wedge ring ( 18 ) is adjacent to wider portion ( 22   a ) of wedge ring ( 20 ), an axis ( 26 ) of the spindle ( 12 ) is normal to the plane ( 28 ) of the back plate ( 16 ). The assembly ( 10 ) is adapted to vary the angle of an axis ( 26 ) of the spindle ( 12 ) relative to a plane ( 28 ) of the back plate ( 16 ) by rotating said at least two wedge rings ( 18 , 20 ) relative to each other and to said back plate ( 16 ). 
     Washers ( 32 ) used with bolts ( 30 ), and nuts ( 34 ) on the bolts ( 30 ) have a portion of a sphere ( 54 ) to accommodate a plurality of angles. 
     The at least two wedge rings ( 18 , 20 ) are adapted to interlock with each other circumferentially, permitting rotation relative to one another while maintaining their circumferential relationship to the back plate ( 16 ). The at least two wedge rings ( 18 , 20 ) each have an outside surface ( 40 , 40   a ) corresponding to its outside diameter and an inside surface ( 41 , 41   a ) corresponding to its inside diameter, and a back plate side ( 44 , 44   a ) oriented toward the back plate ( 16 ) and a spindle plate side ( 46 , 46   a ) oriented toward the spindle ( 12 ), and in the spindle assembly ( 10 ) in a wedge ring ( 18 ) closest to the back plate ( 16 ) the back plate side ( 44 ) forms a ninety degree (90°) angle with the outside surface ( 40 ), and in a wedge ring ( 20 ) closest to the spindle plate ( 14 ) the spindle plate side ( 46   a ) forms a ninety degree angle with the outside surface ( 40   a ). 
     The at least two wedge rings ( 18 , 20 ) are marked with indicia ( 48 , 48   a ) whereby the angle of the axis ( 26 ) of the spindle ( 12 ) relative to a plane ( 28 ) of the back plate ( 16 ) can be determined by the indicia. 
     In one embodiment, the back plate ( 16 ) and spindle plate ( 14 ) are attached to each other by a plurality of bolts ( 30 ), and the at least two interposed wedge rings ( 18 , 20 ) are free to rotate relative to the spindle plate ( 14 ) and the back plate ( 16 ) when the bolts ( 30 ) are not tightened. In a second embodiment, bearings ( 56 ) are interposed between spindle plate ( 14 ) and a wedge ring ( 20 ), and between wedge ring ( 20 ) and wedge ring ( 18 ), and between wedge ring ( 18 ) and back plate ( 16 ) and a pinion gear ( 67 ) is associated with the wedge rings ( 18 , 20 ) for rotating the wedge rings. 
     Also provided is a method for varying the camber angle of a spindle ( 12 ) having a spindle plate ( 14 ), comprising the steps of interposing at least two wedge rings ( 18 , 20 ) between a spindle plate ( 14 ) and a back plate ( 16 ) in a spindle assembly ( 10 ), wherein at least two of the at least two wedge rings ( 18 , 20 ) have a wider portion ( 22 , 22   a ) and a narrower portion ( 24 , 24   a ). 
     The method may comprise the further steps of (a) releasing tension between a back plate ( 16 ) and a spindle plate ( 14 ) in a spindle assembly, and (b) rotating at least two of the at least two wedge rings ( 18 , 20 ) independent of each other and the back plate ( 16 ), or the further steps of (a) associating a pinion gear ( 67 ) with the wedge rings ( 18 , 20 ), and (b) using the pinion gear ( 67 ) to change the angle of spindle ( 12 ). 
     The method may comprise the further step of providing indicia ( 48 , 48   a ) on at least two of the at least two wedge rings ( 18 , 20 ) whereby the exact angle of an axis ( 26 ) of the spindle ( 12 ) relative to a plane ( 28 ) of the back plate ( 16 ) can be determined from the indicia. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 illustrates a side elevational view of a spindle assembly of the invention. 
     FIG. 2 illustrates an elevational view of the assembly from the spindle end. 
     FIG. 3 illustrates a cross sectional view of a spindle assembly of the invention taken along the line  3 — 3  of FIG.  1 . 
     FIG. 4 illustrates a top plan view cross sectional view of a spindle assembly of the invention along the line  4 — 4  of FIG.  1 . 
     FIG. 5 illustrates a side sectional view of a spindle assembly taken along the line  5 — 5  of FIG.  4 . 
     FIG. 6 is a side sectional view showing the spindle in 6° positive position. 
     FIG. 7 is a side sectional view showing the spindle in 6° negative position. 
     FIG. 8 is an enlarged, detached, exploded view of the wedge rings of the spindle assembly. 
     FIG. 9 is an end view of the spindle plate wedge ring showing the indicia. 
     FIG. 10 is an exploded perspective view of the spindle assembly. 
     FIG. 11 illustrates a view similar to FIG. 5 showing an alternative embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The spindle invention is designed to provide angle adjustments in whatever degree increments are desired for testing, e.g. 0.05 degrees, and is capable of substantially an infinite number of angle adjustments. The spindle assembly is composed of four principle parts, the spindle section, at least two wedge rings, and an axle section. Rotating the wedge rings causes the spindle to move in a vertical or horizontal plane to whatever angle is required for testing. The inventor has illustrated embodiments of a passenger tire spindle which uses three degree wedge rings for a plus or minus 6 degrees of adjustment, and has developed a truck tire spindle embodiment, using the same principles, which uses one and one-half degree wedge rings for a plus or minus 3 degree adjustment. 
     The spindle assembly of the invention is designed and illustrated specifically for use with testing equipment, but those skilled in the art will recognize that the spindle assembly can be used on vehicles where quick adjustment of the camber angle is desirable, for example on race cars. 
     With reference now to FIGS. 1-10, a spindle assembly  10  of the invention is illustrated. The spindle  12  is integrally connected to spindle plate  14 , and spindle plate  14  is bolted to back plate  16  which is connected to the axle assembly  17 . In the illustrated embodiment, eight bolts  30  having washers  32  with a spherical portion  54  are used together with nuts  34  to tightly connect back plate  16  to spindle plate  14 . The spherical portion  54  of washers  32  facilitates the different angles encountered between the back plate  16  and spindle plate  14  when the angle of the spindle is adjusted, since substantially even pressure is exerted by washers  32  regardless of the angle of spindle  12 . 
     At least two wedge rings may be interposed between the back plate  16  and the spindle plate  14  to vary the angle of spindle  12  with respect to the axle assembly  17 , and especially with respect to the plane  28  of back plate  16 . At least two wedge rings are needed to vary the angle of the spindle according to the invention, but additional rings may be added to provide more control to changing the angles, provide multiple planes of adjustment, or to improve the accuracy of the angles achieved. 
     In the illustrated embodiment a first wedge ring  18  and a second wedge ring  20  are interposed between back plate  16  and spindle plate  14 . Each of the wedge rings,  18 , 20 , has a wider portion  22 , 22   a  and a narrower portion  24 , 24   a . When a narrower portion  24  of the first wedge ring  18  is adjacent to wider portion  22   a  of second wedge ring  20 , the axis  26  of spindle  12  will be perpendicular to plane  28  of back plate  16 . Conversely, when narrower portion  24  of first wedge ring  18  is adjacent to narrower portion  24   a  of second wedge ring  20 , as illustrated in FIGS. 6 and 7, the maximum angle of the spindle will be seen, the position of the narrower portions  24 , 24   a  determining whether the angle will be positive or negative. 
     With reference now to FIGS. 8 and 9, a first wedge ring  18  is provided with a boss  36  which is adapted to engage register  38  of a second wedge ring  20 . Wedge rings  18 , 20  have a wider portion  22 , 22   a  and a narrower portion  24 , 24   a , and a back plate side  44 , 44   a  and a spindle plate side  46 , 46   a . By “back plate side”, it is meant that when the rings are installed between back plate  16  and spindle plate  14 , the back plate side  44 , 44   a  is installed toward back plate  16 . Likewise, “spindle plate side” means that spindle plate sides  46 , 46   a  are oriented toward spindle plate  14  when wedge rings  18  and  20  are installed between back plate  16  and spindle plate  14 . 
     Wedge rings  18  and  20  have an outside surface  40 , 40   a  and an inside surface  41 , 41   a . Indicia  48  is located on the back plate side  44  of wedge ring  18 , and indicia  48   a  is located on the spindle plate side  46   a  of wedge ring  20 . Rotating means  50 , 50   a  are used to turn the wedge rings when nuts  34  are loosened on bolts  30 . 
     When incorporated in spindle assembly  10 , the inside surface  41   a  of wedge ring  20  rests on shoulder  13  of spindle plate  14 , and the inside surface  41  of wedge ring  18  rests on shoulder  15  of back plate  16 . Shoulders  13 , 15  stabilize wedge rings  18 , 20  in the assembly, and together with boss  36  and register  38 , which provide an interlocking relationship between wedge rings  18  and  20 , insure that the angles indicated by indicia  48 , 48   a  are consistent as the angles of spindle  12  are changed back and forth. 
     In the illustrated embodiment, rotating means  50 , 50   a  are levers projecting from the outside surface  40 , 40   a  of the wedge rings  18 , 20 , which can be used to provide leverage for turning a wedge ring when a change of camber angle for the spindle is desired. Other means of turning the wedge rings will be apparent to those skilled in the art. 
     In the illustrated embodiment, the outside surfaces  40 , 40   a  form a 90-degree angle with the back plate side  44  of wedge ring  18 , and a 90-degree angle with the spindle plate side  46   a  of wedge ring  20 . The center of the wedge ring is determined by measuring the center of the angled face  46  of wedge ring  18 , and the angled face  44   a  of wedge ring  20 . Determining the center of wedge ring  18 , 20  on the angled face places the axis point  47 , 47   a  on the angled side of the wedge ring. Thus, when wedge ring  18  and wedge ring  20  are interposed between back plate  16  and spindle plate  14 , the axis points  47 , 47   a  of the two wedge rings are contiguous with each other. 
     The inventor has found that when the wedge rings are made such that the axis points  47 , 47   a  are on opposite sides of the wedge rings, away from each other in spindle assembly  10 , the two axis points, being separated by the total width of the wedge rings, may create an oscillation in the rotation of the spindle. The invention has been found to be operable with these two separated axis points, however, when a shoe  52  is placed in the axis assembly  17 , to dampen or eliminate the oscillation. 
     Shoe  52  is flat on spindle plate side  53 , and square boss  61  on spindle plate  14  fits into register  62  of shoe  52  in spindle assembly  10 . Back plate side  51  of shoe  52  is curved, to permit changing angles in the vertical plane without binding the spindle assembly  10 . 
     The shoe  52  also allows for multiple planes of motion when an additional pair of wedge rings are used. The shoe  52  moves within the axis assembly  17  on curved back plate side  51  to allow one plane of motion, and the boss  61  on the wedge ring side of the spindle plate  14  is free to move within register  62  on the inside of the shoe  52  to allow the other plane of motion. 
     In the implementation of the invention, to vary the angle of the spindle, nuts  34  on bolts  30  are loosened sufficiently to permit movement or rotation of wedge rings  18  and  20 , and rotation means  50 , 50   a  on the wedge rings  18 , 20  provide leverage for turning the rings. Marks are provided on the back plate  16  and the spindle plate  14  which are used for aligning indicia  48 , 48   a  for the desired angle. In the illustrated embodiment, if 2.5 degrees is the desired angle of the spindle, the indicia of wedge ring  18  is placed at the mark on the back plate  16  to read 2.5 degrees and the indicia  48   a  on wedge ring  20  is placed at the mark on the spindle plate  14  to read 2.5 degrees. Nuts  34  are then tightened on bolts  30  until the spindle assembly is secure. Spherical portion  54  of washers  32  accommodate the change in angle by providing consistent contact throughout the perimeter of bore holes  31  in the back plate  16  and spindle plate  14 , regardless of the angle of adjustment. 
     Those skilled in the art will recognize that other systems with different indicia arrangements can be used to obtain the desired angles. 
     With reference now to FIG. 11, in an alternative embodiment, bearings  59 , such as ball bearings or roller bearings, may be mounted in wedge rings  18  and  20  to simplify and make easier rotation of the wedge rings to the desired location. An additional stabilizing plate  33  can be used to make possible changing the spindle angles without loosening bolts  30 . The stabilizing plate  33  remains parallel to the spindle plate when the angle of spindle  12  is changed. Accordingly, when the angle of spindle plate  14  is changed, stabilizing plate  33  moves against surface  19  of axle assembly  17 . Assuming the back plate remains stationary (attached to the axle), when the widest part of the wedges are rotated to the top of assembly  10 , this would cause the spindle to turn down. When the widest part of the wedges are at the top, the top cross-section width becomes greater, and the resulting cross-section at the bottom of assembly  10  becomes narrower. When both wedge rings are rotated at the same time, the total cross section width of the wedge rings at angular displacement locations of 90° and 270° from the top of the spindle assembly  10  remain equal to each other. When the widest part of the wedges are at the top of assembly  10 , this normally requires nuts  34  to be loosened to allow for the increase in cross section width. Conversely, the nuts  34  at the bottom of assembly  10  would have to be tightened to allow for the decrease in cross section width. The stabilizing plate  33  being free to move against surface  19  and remaining parallel to spindle plate  14  keeps the distance contained by bolt  30  and nut  34  constant throughout the angle adjustment of spindle  12 . This arrangement makes it unnecessary to loosen or tighten the bolts as the wedge rings  18 , 20  are moved. It is necessary that the dimension  56  and  57  (the horizontal distance between the washer pivots  58  and the plate pivots  59 , 60 ) be the same for both plates to keep the “bolt length” equal. The radius from the plate pivot  59 , 60  to each of the washer pivots  58  would then be equal by design. Conical spring washers may still be required under the bolt head, or similar mechanical arrangements be made, to make up any slight irregularities and make allowances for wear, and to maintain the pre-load on the bearings. The two wedge rings would need to be coupled so that they move an equal distance simultaneously in opposite directions. This can be accomplished by using a pinion gear  67  on the centerline between the two wedge rings  18 , 20 , and in mesh with gear teeth  68  of both wedge rings  18 , 20 . 
     As illustrated above, spindle assembly  10  is designed primarily for angle adjustments in the vertical plane, i.e. ±6 degrees vertical (i.e. perpendicular to the contact testing surface of a wheel mounted on spindle  12 ). It is contemplated by the inventor that at least two additional wedge rings can be added to the assembly to vary the spindle angle in the horizontal plane, functioning in the same manner as wedge rings  18 , 20 , but having an angular displacement of 90° as compared to the orientation of wedge rings  18 , 20 . As discussed above, the dimensions of shoe  52  will permit movement of boss  61  in register  62  of shoe  52  to permit such angular displacement.