Abstract:
A gauge device and the associated method of using the gauge device to set the cut angles of a carpenter&#39;s mitering tools. The device includes a handle that has a longitudinal axis. A first arm is pivotably connected to the handle. The first arm has at least one straight edge. The straight edge of the first arm creates a first angle relative the longitudinal axis of the handle. A second arm is also pivotably connected to the handle. The second arm has a straight edge that creates a second angle relative the longitudinal axis of the handle. A spanning mechanism is provided that selectively maintains symmetry between the first angle of the first arm and the second angle of the second arm. The second arm is selectively detachable from the spanning mechanism and is movable to a retracted position. The second arm is retracted when the gauge device is used to set the cutting angle on a mitering tool.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     In general, the present invention relates to gauges used to measure the angle between converging or diverging surfaces. More particularly, the present invention relates to hand held tools used in carpentry that are used to measure angles so that various carpentry tools can be set to the measured angles and produce accurate mitered cuts. 
     2. Description of the Prior Art 
     Carpenters are often required to join pieces of wood at corners. When joining pieces of wood at an angle, the ends of the pieces of the wood must be mitered in order to match the angle of the corner and produce an aesthetically pleasing joint. When corners meet at a right angle, the mitering process is relatively simple. However, when pieces of wood are joined at an acute angle or at an obtuse angle, the task of creating a proper joint becomes more complex. 
     In carpentry, the first step needed to create a proper joint between converging surfaces is to measure the angle between the converging surfaces. Once the angle is known, the measured angle is bisected and the carpenter&#39;s mitering tools are set to the value of the bisected angle. Both converging pieces of wood are then cut to the bisected angle. When the two pieces of wood are joined, the pieces of wood meet at an angle equal to the measured angle and a proper joint is created. 
     The prior art is replete with various different types of gauges that are used to measure the angle between converging or diverging surfaces. Early carpentry tools used to measure angles had two articulated arms that were joined to a common pivot point. The arms were rotated to match the angle of the surface being measured. A protractor was then used to measure the angle between the arms, so a carpenter new at what angle to set his tools. Such prior art gauging tools are exemplified by U.S. Pat. No. 1,135,743 to Walker, entitled Combination Tool. 
     In the years that followed, gauging tools have been improved in that a protractor has been incorporated into the gauge. As such, a carpenter can read an angle directly from the gauge rather than having to use both a gauge and a protractor. Such prior art gauges are exemplified by U.S. Pat. No. 4,060,900 to Greenwood, entitled Angle Measuring Device and U.S. Pat. No. 4,535,542 to Liu, entitled Vernier Gauge. 
     A problem associated with the use of such prior art angle gauges is tolerance error. When a carpenter measures an angle, the measured angle contains some error that corresponds to the quality of the gauge being used and the care taken by the carpenter when measuring the angle. Additionally, the measured angle is then divided in half, which often produces rounding errors. The calculated value of the bisected angle is then used to set the carpenter&#39;s mitering tools. The tools often do not have highly accurate angle setting devices and the mitering tool may have a tolerance error of ±2 degrees. The combined errors created by the gauge, the mitering tool and rounding errors often cause the resulting joint to be less than perfect. As such, a carpenter must repeat the process or subject the wood to a secondary cutting process until a joint of satisfactory quality is obtained. 
     If a carpenter is making high quality furniture, picture frames or trim where a very small margin of error is acceptable, the carpenter typically uses very high quality gauges and mitering tools. Such high quality tools do produce accurate cuts. However, such tools are very expensive and are not economically practical to many professional and amateur carpenters. 
     A need therefore exists for a device and method for accurately gauging an angle and setting inexpensive mitering tools to the measured angle, thereby enabling accurate miters to be dependably produced from common equipment. This need is met by the present invention as it is described and claimed below. 
     SUMMARY OF THE INVENTION 
     The present invention is a gauge device and the associated method of using the gauge device to set the cut angles of a carpenter&#39;s mitering tools. The device includes a handle that has a longitudinal axis. A first arm is pivotably connected to the handle. The first arm has at least one straight edge. The straight edge of the first arm creates a first angle with the longitudinal axis of the handle. A second arm is also pivotably connected to the handle. The second arm has a straight edge that creates a second angle with the longitudinal axis of the handle. A spanning mechanism is provided that selectively maintains symmetry between the first angle of the first arm and the second angle of the second arm. The second arm is selectively detachable from the spanning mechanism and is movable to a retracted position. The second arm is retracted when the gauge device is used to set the cutting angle on a mitering tool. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention, reference is made to the following description of exemplary embodiments thereof, considered in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a front view of a first embodiment of a gauge device shown in conjunction with an angled surface that is to be gauged; 
     FIG. 2 is a front view of the embodiment of the gauge device shown in FIG. 1 wherein the second arm element has been retracted; 
     FIG. 3 is a top view of a power miter box, wherein the gauge device of FIG. 2 is being used to set the angle of the cutting blade; 
     FIG. 4 is a partially cross-sectioned forward view of a gauge device in accordance with the present invention; 
     FIG. 5 is a cross-sectional view of the embodiment of FIG. 4, viewed along section line  5 — 5 ; and 
     FIG. 6 is a front view of an alternate embodiment of an angle gauge in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a first embodiment of the present invention gauge device  10  is shown in conjunction with an angled surface  12  that is to be gauged. The gauge device  10  includes a handle  14 , a first arm element  16  and a second arm element  18 . The first arm element  16  and the second arm element  18  are pivotably connected to the handle  14 . As such, the two arm elements  16 ,  18  can be pivotably rotated into a configuration that matches the angled surface  12  being gauged. 
     The first arm element  16  has a first flat edge  20  that faces away from the handle  14 . Similarly, the second arm element  18  has a second flat edge  22  that faces away from the handle  14 . The handle  14  also has a flat edge  24 , which lays adjacent the second arm element  18 . The handle  14  is elongated and has a central longitudinal axis  26 . The flat edge  24  of the handle  14  lays parallel to the longitudinal axis  26  of the handle  14 . The first arm element  16  and the second arm element  18  symmetrically extend from the handle  14 . As such, the angle A between the first flat edge  20  on the first arm element  16  and the longitudinal axis  26  of the handle  14  remains the same as the angle A between the second flat edge  22  on the second arm element  18  and the longitudinal axis  26  of the handle  14 . The symmetry between the longitudinal axis  26  of the handle  14  and the two flat edges  20 ,  22  of the arm elements  16 ,  18  is maintained by a spanning mechanism, that will later be explained. Accordingly, no matter what angle the first arm element  16  is adjusted to, the second arm element  18  will automatically extend to the same angle as the first arm element  16 . 
     The arm elements  16 ,  18  are adjusted so that the flat edges  20 ,  22  of the arm elements  16 ,  18  lay flush against the edges of the angled surface  12  being gauged. Once the flat surfaces  20 ,  22  of the arm elements  16 ,  18  match the angled surface  12 , the arm elements  16 ,  18  are locked into place by a locking mechanism, that will also later be explained. 
     Once locked into place, the gauge device  10  is removed from the angled surface  12 . The angle B between the two flat edges  20 ,  22  of the two arm elements  16 ,  18  represents the angle between the surfaces of the angled surface  12  that was just gauged. The measurement is nearly exact because the gauge device  10  is pressed against the angled surface  12  and the arm elements  16 ,  18  are locked into place when the arm elements  16 ,  18  contact the angled surface  12 . 
     Since the first arm element  16  and the second arm element  18  are symmetrically disposed on either side of the longitudinal axis  26  of the handle  14 , the angle A between the first flat edge  20  on the first arm element  16  and the longitudinal axis  26  represents the exact bisection of the angle B between the two flat edges  20 ,  22  of the two arm elements  16 ,  18 . 
     In the present invention, the second arm element  18  can be selectively disengaged from the spanning mechanism that maintains symmetry between the first arm element  16  and the second arm element  18 . Once disengaged, the second arm element  18  can be either removed or retracted. The result is the configuration shown in FIG.  2 . Referring to FIG. 2, it can be seen that once the second arm element  18  (FIG. 1) is removed or retracted, the first arm element  16  remains in the same location. As such, the angle A between the flat edge  20  on the first arm element  16  and the longitudinal axis  26  of the handle  14  remains equal to the bisection of the gauged angle B (FIG. 1) measured by the gauge device  10 . However, the angle C between the flat edge  20  of the first arm element  16  and the flat edge  24  of the handle  14  is equal to the bisection of angle A plus 180°. 
     Referring to FIG. 3, it can be seen that the gauge device  10  can be used to set a mitering tool  30 . In the illustration of FIG. 3, the mitering tool  30  is a power miter box having a blade  32  and a straight support fence  34 . The angle between the blade  32  and the support fence  34  can be altered to different angles. To utilize the present invention gauge device  10 , the flat edge  24  of the handle  14  is placed flush against the support fence  34  of the power miter box. The blade  32  of the power miter box is then adjusted to meet the angle of the flat edge  20  of the first arm element  16 . If the power miter box has an adjustment gauge, the adjustment gauge is ignored. Rather, the blade  32  is adjusted until the blade  32  lays flush against the flat edge  20  of the first arm element  16 . Once in abutment with the first arm element  16 , the blade  32  is locked into place. 
     Once the blade  32  of the power miter box is locked into place, the gauge device  10  is removed. Within a very small margin of error, the resulting angle between the blade  32  and the support fence  34  is nearly exactly the angle between the flat edge  20  of the first arm element  16  and the longitudinal axis of the handle  14 . Accordingly, any wood cut in the power miter box will be cut at an angle equal to the bisected angle of the actual angle measured by the gauge device  10 , as is required for making a proper joint. 
     In FIG. 3, the use of a power miter box is merely exemplary. The gauge device  10  can be used to set any cutting tool where the blade of the tool and a support fence on the tool are adjustable. As such, the gauge device can be used to set a table saw, router table, shaper table, band saw, drum sander and the like. 
     Furthermore, in the embodiment of the gauge device shown in FIG.  1  and FIG. 2, the gauge device  10  was used to measure an angled surface that resulted in the angle A, between the first arm element  16  and the longitudinal axis  26  of the handle  14  being an acute angle. The gauge device  10  is also capable of gauging more salient angled surfaces, wherein the angle A between the first arm element  16  and the longitudinal axis  26  of the handle would be an obtuse angle. 
     Referring now to FIG. 4, an alternate embodiment of the present invention gauge device  40  is shown. In this embodiment, the spanning mechanism is shown. The spanning mechanism is the device that maintains the first and second arm elements  41 ,  42  symmetrically around the longitudinal axis  43  of the handle  44 . In the shown embodiment, a first gear  45  is mounted to the end of the first arm element  41 . The first gear  45  is concentrically positioned with the first pivot post  46  that joins the first arm element  41  to the handle  44 . A second gear  47  is mounted to the end of the second arm element  42 . The second gear  47  is concentrically positioned with a second pivot post  48  that joins the second arm element  42  to the handle  44 . The two gears  45 ,  47  intermesh and have both the same diameter and tooth pitch. As a result, when the first arm element  41  is rotated upwardly, the gears turn and the second arm element  42  is caused to move in a symmetric manner. 
     The handle  44  is hollow. As such, when the first arm element  41  and/or the second arm element  42  is retracted, the retracted arm element or elements can be retracted into the handle  44 . 
     Referring to FIG. 5, it can be seen that a locking nut  50  is threaded onto the first pivot post  46  that joins the first arm element  41  and the first gear  45  to the handle  44 . By selectively tightening the locking nut  50 , the first arm element  41  can be locked into one set position relative the handle  44 . As such, the locking nut  50  serves as a locking mechanism for locking the first locking arm  41  in place after the gauge device is configured to match an angled surface. 
     The second arm element  42  extends into an open slot  52  in the handle  44 . The width of the slot  52  is wider than the combined widths of the second arm element  42  and the second gear  47  that is coupled to the second arm element  42 . The second arm element  42  and the second gear  47  are biased against one side of the slot  52  by a spring  54 . When biased against the side of the slot  52  by the spring  54 , the second gear  47  is intermeshed with the first gear  45  and the spanning mechanism is operational. However, the second pivot post  48  has a flat head that extends out of the handle  44 . When the flat head of the second pivot post  48  is depressed in the direction of arrow  55 , the second arm element  42  and the second gear element  47  are pushed to the opposite side of the slot  52  against the bias of the spring  54 . Once moved against the bias of the spring  54 , the second gear  47  disengages from the first gear  45 . The second arm element  42  is therefore free to move without effecting the first arm element  41 . The ability of the second arm element  42  to disengage from the spanning mechanism, enables the second arm element  42  to be moved to a retracted position without effecting the first arm element  41 . 
     Referring now to FIG. 6, another alternate embodiment of the present invention gauge device  60  is shown. Like with previous embodiments, the gauge device  60  includes an elongated handle  62  and two arm elements  64 ,  66 . The two arm elements  64 ,  66  are pivotably connected to the handle  62 . The handle  62  contains a slot  68  that runs along the longitudinal axis of the handle  62 . Within the slot  68  is positioned a slide element  70 . The slide element  70  includes a locking nut  72  that can be used to lock the slide element  70  in place within the slot  68 . When the locking nut  72  is not tightened, the slide element  70  is free to move back and forth along the length of the slot  68 . 
     In the embodiment of FIG. 6, the spanning mechanism includes two linkage elements  73 ,  74 . The first linkage element  73  is pivotably connected at one end to the first arm element  64 . The opposite side of the first linkage element  73  is pivotably connected to the slide element  70 . Accordingly, as the slide element  70  is moved back and forth within the slot  68 , the linkage arm  73  causes the first arm element  64  to rise and fall. 
     The second linkage element  74  is pivotably connected at one end to the second arm element  66 . The opposite side of the second linkage element  74  is pivotably connected to the slide element  70 . Accordingly, as the slide element  70  is moved back and forth within the slot  68 , the linkage arm  74  causes the second arm element  66  to rise and fall. 
     The first linkage element  73  and the second linkage arm element  74  are the same length and engage the first and second arm elements  64 ,  66  at the same points, respectively. Accordingly, as the slide element  70  moves up and down in the slot  68 , the first arm element  64  and the second arm element  66  move in unison and the angle between the arm elements and the longitudinal axis of the handle remains the same. 
     The second linkage element  74  can be selectively disconnected from the slide element  70 . Once the second linkage element  74  is disconnected from the slide element  70 , the second arm element  66  is free to move independently of both the slide element  70  and the first arm element  64 . 
     To use the gauge device  60 , both linkage elements  73 ,  74  are coupled to the slide element  70 . The first arm element  64  and the second arm element  66  are then configured to match the angle of a surface against which the arm elements  64 ,  66  are pressed. Once at a proper orientation, the slide element  70  is locked into place on the handle  62  using the locking nut  72 . This locks the first arm element  64  and the second arm element  66  into a set position. The second linkage arm  74  is then detached from the slide element  70 . This enables the second arm element  66  to move independently, wherein the second arm element  66  can be moved to a retracted position. Once the second arm element  66  is retracted, the first arm element  64  and the handle  62  are used to set a miter tool in that same way as has been previously described. 
     It will be understood that the embodiments of the present invention gauge device that are described and illustrated herein are merely exemplary and a person skilled in the art can make many variations to the embodiment shown without departing from the scope of the present invention. For example, there are many known mechanisms that can be adapted for use as spanning mechanisms or locking mechanisms to the gauge device. Furthermore, the length of the arm elements and length of the handle can be altered as desired. The features required for the operation of the gauge element are two arm elements, a handle, a spanning mechanism that moves the arm elements symmetrically from the handle, and a means to remove or retract one of the arms. All variations, modifications and alternate embodiments to these structures that serve the stated function are intended to be included within the scope of the present invention as defined by the appended claims.