Abstract:
The caliper gauge has a V-shaped gauge body. The V-shaped gauge body has stepped pairs of measuring surfaces both externally and internally of the V-shaped gage body. The pairs of measuring surfaces are a known distance apart for setting external and internal calipers. The gauge body may rest against a back plate, which prevents the caliper from being dislodged from the measuring surface. Indicia are provided for both the external measuring surfaces and internal measuring surfaces on the gauge body.

Description:
CROSS REFERENCE 
   This application relies on provisional patent application, Ser. No. 60/468,755, filed May 8, 2003, for “Caliper Gauge” for priority. 

   FIELD OF THE INVENTION 
   Calipers of various types are used in woodworking shops and other trades and professions for setting dimensions. A caliper is adjust with respect to a measuring standard, and then the caliper is taken to the workpiece to determine if the workpiece is to size. The caliper gauge of this invention is for accurately setting a caliper to a specific dimension or accurately measuring the span of a previously set caliper. 
   BACKGROUND OF THE INVENTION 
   Calipers have been created in different configurations for different purposes. They have their use in a vast array of fields from architectural and engineering drafting to furniture making and measuring. They are used in machine-shop work and for measuring navigational maps and the like. The present method for measuring or setting a caliper is to lay it on a ruler and read the opening of the caliper against the ruler markings. This approach is very inaccurate, inconsistent and thus open to errors. A previously known device for setting outside calipers is called a “turning tree,” which is a solid of revolution which has a plurality of decreasing cylinders of known diameters. Such a device is accurate when properly used, but it is difficult to assure that the caliper gauge tips are precisely set on the exact diameter. There is need for a gauge by which a caliper can be set accurately and accurately read. 
   SUMMARY OF THE INVENTION 
   In order to aid in the understanding of this invention, it can be stated in essentially summary form that it is directed to a caliper gauge which has a plurality of measuring surfaces which are accurately spaced from each other. Each pair of these measuring surfaces is at a known distance apart. Associated with each measuring surface are two stop surfaces. The back stop prevents the caliper from leaving the measuring surface in one direction, and the adjacent step face prevents the caliper from leaving the measuring surface in another direction so that the caliper gauge can be retained on the selected pair of measuring surfaces while the caliper is being adjusted. 
   It is, thus, a purpose and advantage of this invention to provide a caliper gauge which permits easy positioning of the caliper with respect to the gauge to hold the caliper in place while it is being adjusted. 
   It is another purpose and advantage of this invention to provide a caliper gauge which has a plurality of pairs of spaced measuring surfaces which are spaced a known distance and which have indicia related thereto so that the measurement therebetween can be quickly established. 
   It is another purpose and advantage of this invention to provide a caliper gauge of such construction that it can be placed on a base or secured against an upright so that it can be conveniently positioned adjacent to the place of desired measurement. 
   It is a further purpose and advantage of this invention to provide a caliper gauge which has two sets of pairs of measuring surfaces, with one set being positioned for inside measurement and the other set being positioned for outside measurement. 
   It is a further purpose and advantage of this invention to provide a simple and accurate caliper gauge for measuring and establishing the inside and outside measurement distances with any type of calipers. 
   Other purposes and advantages of this invention will be noted from the study of the following portion of the specification, the drawings and the attached claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view from the front and slightly to the left and slightly above the caliper gauge of this invention. 
       FIG. 2  is a left side view thereof. 
       FIG. 3  is a front view thereof showing an inside caliper being set on the caliper gauge of this invention. 
       FIG. 4  is a downwardly looking section, taken generally along the line  4 — 4  of FIG.  3 . 
       FIG. 5  is a front view showing an outside caliper being set on the caliper gauge of this invention. 
       FIG. 6  is a top view of the structure of FIG.  5 . 
       FIG. 7  is a view similar to  FIG. 1  showing the caliper gauge mounted on a backboard. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The caliper gauge of this invention is generally indicated at  10  in  FIGS. 1 through 7 . The caliper gauge is comprised of a back plate  12  which has a substantially planar front surface  14 . As will be later described, the front surface  14  acts as a stop to aid in the placement of the caliper being set with respect thereto. The back plate may be rectangular, but it is preferably in the shape of an inverted V, as shown in  FIGS. 1 ,  3 ,  5  and  7 . 
   Gauge body  16  is mounted on the front of the back plate. The gauge body  16  is in the form of an inverted V, but the inside and outside surfaces of the gauge body are in the form of stair steps. The stair steps are configured so that the lateral distance across the stair steps is a known value. It is these distances which are the reference distances to which the caliper gauge will be set. The gauge body  16  is seen to have these stair steps both on the inside and outside of the inverted V.  FIGS. 3 and 4  show the inside stair steps are positioned to set an inside caliper.  FIGS. 5 and 6  show how the outside stair steps are utilized to set an outside caliper. It is important to note that the step and gauge surfaces of each stair step plus the front of the back plate permit easy location of the fingers of the caliper. One cannot thrust these fingers too far back, beyond measuring range, because the back plate is present to limit position of the fingers in that direction. The adjacent step of the stair steps limits the caliper from being moved in the smaller direction for the inside caliper, see  FIG. 3 , and prevents it from moving in the larger direction for an outside caliper, as seen in FIG.  5 . The caliper fingers are thus constrained by three different surfaces so that it is easy to properly position the caliper for its accurate setting. 
   In order to quickly identify the desired pair of gauge surfaces, the surfaces are marked in several ways. In the example shown in the drawings, the measurements are in the English system. The relationships could just as well be established in the metric system. There is a plurality of steps, and the distance across these steps successively increases by {fraction (1/16)} inch. The line  18 , see  FIG. 1 , indicates that the gauge surfaces at that line are a pair of gauge surfaces. The indicia  20  shows that the measuring surfaces are ½ inch apart. The indicia  22  indicates that the measuring surfaces are 0.50 inch apart. Thus, the indicia down the left side of the scale are in fractions, and the indicia down the right side are in {fraction (1/100)} of an inch. As an example, measuring surfaces  24  and  26  are 1½ inches apart. The indicia “1½” are shown on the left side, and the indicia “1.50” is shown on the right side. The step faces  28  and  30  are directly below the measuring surfaces and lead to the next step, which is {fraction (1/16)} inch wider. 
   The indicia  32  and  34  indicate that the measuring surfaces are 1½ inch apart, with suitable tolerances. The measuring surfaces directly thereabove are {fraction (1/16)} inch closer and, thus, are 1{fraction (7/16)} inches apart. The measuring surfaces directly below the surfaces  24  and  26  are {fraction (1/16)} inch wider apart, and thus are 1{fraction (9/16)} inches apart. This progression extends up and down the outside of the gauge body  16 . Line  18  is the top indicator line, which visually aids in making sure that the proper pair of measuring surfaces is employed. Another of such indicator lines is indicated at  36  at the 1½ inch measuring surface. It is also seen that such indicator lines are presented across the back plate  12  and across the gauge body at each four measuring steps. Indicia may be applied wherever helpful to aid the artisan in selecting the correct pair of measuring steps. Other measuring step intervals than the measuring steps of this example which are progressively {fraction (1/16)} inch larger than the previous pair of steps, can be utilized. 
   The indicator lines extending across the face of the back plate and across the face of the gauge body aid in selecting the desired pair of measuring surfaces. This arrangement is suitable for setting an outside caliper  38 , as seen in  FIGS. 5 and 6 . The fingers of the caliper are placed on the larger step face adjacent the selected measuring surface. The fingers of the outside caliper are rested against the front surface  14  of the back plate. The caliper is then adjusted so that the fingers touch the selected measuring surfaces with the correct amount of resistance to achieve accurate setting of the caliper  38 . 
   In addition to the outside measuring surfaces just described, which are suitable for the setting of outside calipers, the gauge body is provided with a plurality of stepped inside measuring surfaces. These inside measuring surfaces face each other and are a known distance apart. Measuring surfaces  40  and  42  are shown in  FIG. 1  as facing each other. These surfaces are in step relationship to a plurality of such pairs of measuring surfaces. Each of the pairs of measuring surfaces is a known distance apart so that an inside caliper  46  can be adjusted with respect thereto. The inside caliper  46  is shown in  FIGS. 3 and 4 . The measuring location is defined by these measuring surfaces, the adjacent step to the next smaller measuring surface and the front surface of the back plate. Thus, the fingers of the inside caliper  46  can be easily and securely engaged and retained on the selected pair of measuring surfaces. Indicia  48  and  50  shown in  FIG. 1  indicate the dimension between these measuring surfaces. It is convenient to have the indicator lines  18  and  36  extend all the way across so that the selected pair of measuring surfaces can be more easily found. 
   In order to place the caliper gauge  10  at a location where it is convenient, it is provided with a base  52 . The base  52  has a slot  54  therein which is sized to receive the back plate and gauge body. The base is sufficiently wide to permit the caliper gauge to stand upright, as seen in FIG.  1 . For an additional mounting opportunity, the back plate  12  has screw holes  56  and  58  therein. This permits the back plate with its gauge body to be attached to a back board  60  shown in FIG.  7 . The back board  60  may be attached to a wall or post by means of screws  62  and  64 . As an alternative to the back board  60 , the back plate  12  and gauge body can be attached directly to a post, a machine tool or to the end of a tool box by means of screws  66  and  68 . Thus, it is clear that the caliper gauge  10  provides an easily used caliper setting tool which can be placed or secured conveniently to the function at which calipers need to be quickly and accurately set. 
   This invention has been described in its presently preferred embodiment, and it is clear that it is susceptible to numerous modifications, modes and embodiments within the ability of those skilled in the art and without the exercise of the inventive faculty. Accordingly, the scope of this invention is defined by the scope of the following claims.