Abstract:
A brake disc and drum measuring device featuring an elongated member attached to two pairs of jaws extending in opposite directions from the member. A first of said first pair of jaws engaged to said member is adapted to measure a brake rotor while as second pair of jaws measures brake drums. A digital display is always in view with digital indicia right-side-up when the device is being employed in the as-used position with the first pair of jaws extending upward relative to the user&#39;s face. Large shoulders on a second pair of jaws provide for easy positioning on brake drums having oversized extensions from their sidewall. A moveably jaw on the second pair also allows the device to be balanced.

Description:
[0001]    This application claims priority from U.S. Provisional Patent Application Ser. No. 60/901,526 filed Feb. 14, 2007, and incorporated in its entirety by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The disclosed system and method relates to the taking of accurate mechanical measurements for machining purposes. More particularly, it relates to a device providing electronic measurements of both disc brake calipers and conventional drum brake drums in a single and highly accurate measuring instrument. 
       BACKGROUND OF THE INVENTION 
       [0003]    Automobiles, trucks, airplanes, and other vehicles which roll on wheels across a road or surface are equipped with brakes to slow the vehicle and also to stop it from rolling. Such wheeled brake systems exist primarily in two types which include disc and drum braking systems. 
         [0004]    The typical conventional brake system consists of disc brakes on the front wheels and either disc or drum brakes on the rear wheels connected by a system of tubes and hoses that link the brake at each wheel to the master cylinder. Other systems that are connected with the brake system include the parking brakes, the power brake booster and the anti-lock system. 
         [0005]    Employing a brake hydraulic system, stepping on the brake pedal forces hydraulic oil (brake fluid) through a series of tubes and hoses to the braking unit at each wheel. Since fluid cannot be compressed, pushing fluid through the conduit is just like pushing a steel bar through a pipe and the many twists and turns on its way to its destination. Once reaching the wheel, the fluid imparts the exact same motion and pressure to a caliper or lave cylinder. 
         [0006]    In a disc brake type system, the fluid from the master cylinder is forced into a caliper where it presses against a piston. The piston, in-turn, squeezes two brake pads against opposing contact surfaces on a planar rotor which is attached to the wheel, forcing it to slow down or stop. 
         [0007]    In a drum brake system, the fluid is forced into the wheel slave cylinder which pushes the brake shoes out so that the friction linings press against a contact surface on the drum which is attached to the wheel, causing the wheel to stop. 
         [0008]    In either case, the friction surfaces of the pads on a disc brake system, or the shoes on a drum brake convert the forward motion of the vehicle into heat. Heat is what causes the friction surfaces (linings) of the pads and shoes to eventually wear out and require replacement. Consequently, in both types of systems there is an eventual need of repair since over time the friction of the shoes and pads on the contact surfaces of the drum and rotors respectively will cause the contact surface to wear and will impair full contact of the discs and shoes with their contact surfaces. Incomplete contact, of course, causes the braking system to become dysfunctional or less efficient. 
         [0009]    Consequently, in both types of systems, the contact surfaces upon which the shoes engage the drum, or the pads engage the rotor, must be occasionally resurfaced to insure complete contact of the frictional pads and shoes with the surface they contact. 
         [0010]    Since resurfacing involves removing metal material from the structure of the rotor or the drum, it is imperative that good measurements are taken of the surface to be machined, to insure that only the amount necessary is removed from the structures. Also imperative is ascertaining that the final structure, after the removal of metal, is of sufficient thickness to be operated safely. This is because over turning of the rotor or drum to smooth the contact surface can cause too much material to be removed, rendering the drum or disc unsafe to use. 
         [0011]    Commonly employed in the measurement of metal surfaces being subjected to machining is a caliper which the user engages against the side contact surface to be resurfaced and the opposite side to ascertain a thickness of the part. Some are adapted to measure both discs and drums. However, such devices are configured to require the user to hold the very heavy drum in the air while measuring it, or to employ display gauges which cannot be read right-side up or easily while holding the caliper in contact with the drum. 
         [0012]    Accordingly, there is an unmet need for a measuring device which will accurately measure both disc brake rotors and drum brake contact surfaces and which will provide accurate measurements of either type of surface using a single measuring instrument engaged to an electronic meter and display. Such a device should position the digital display of the distance being measured in easy view of the user. Further, such a device should provide a means to support the device on a heavy brake drum and easily take and read the measurement of the diameter of the drum. 
         [0013]    In this respect, before explaining at least one 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 arrangement of the components set forth in the following description or illustrated in the drawings nor the steps outlined in the specification. The invention is capable of other embodiments and of being practiced and carried out in various ways as those skilled in the art will readily ascertain from reading this application. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
         [0014]    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 designing other methods and systems for carrying out the several purposes of the present invention of a brake disc and drum measuring instrument. It is important, therefore, that the claims be regarded as including such equivalent construction insofar as they do not depart from the spirit and scope of the present invention. 
       OBJECTS OF THE INVENTION 
       [0015]    An object of this invention is the provision of a combination disc and drum brake measuring device. 
         [0016]    An additional object of this invention is the provision of such a measuring device that has surfaces allowing it to rest upon heavy brake drums while concurrently providing accurate diameter measurements of the drum. 
         [0017]    Yet another object of this invention is to provide such a device which is configured to allow the user to easily see the digital display during use without straining or going into awkward positions. 
         [0018]    It is thus an object of the invention to provide a device for measuring both disc brake rotors and drum brake drums which allows for easy reading of the electronic display during use for either measurement and a support on the drum to insure equal depth of both measuring points. These together with other objects and advantages which will become subsequently apparent reside in the details of the construction and method as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part thereof, wherein like numerals refer to like parts throughout. 
       SUMMARY OF THE INVENTION 
       [0019]    The disclosed device provides for accurate measurements of both disc brake rotors and drum brake drums in a single instrument that is easy to employ by a user. Conventional electronic disc &amp; drum brake calipers are available from various sources. However, such devices conventionally employ opposing outside measuring jaws for measuring the thickness of the discs which are designed to point downward towards the feet of the person reading the measurement from LCD display when in the as-used position in the hands of the user while measuring a disc. Such conventional devices may also employ a set of inside measuring jaws which are employed to measure the inside diameter of a brake drum. Conventionally, these inside measuring jaws point upward or away from the person or their feet, when the device is in the as-used position in the user&#39;s hand reading the LCD display. 
         [0020]    Configuring the display read out and opposing jaws in this fashion makes it very difficult, in both cases, for the user to actually read the LCD display, while concurrently trying to hold the heavy parts and trying to bias the jaws being used toward the surfaces being measured to take the measurement. 
         [0021]    The device disclosed and described herein, employs the outside measuring jaws (for disc thickness measurement) which in the as-used position, points upward and away from the feet or chest of the user depending on the placement of the disc being measured. The disclosed device also provides translatable inside measuring jaws (for measuring the drum diameter measurement), both of which point downward toward the feet or body of the user when in the as-used position. An electronic gauge, operatively engaged to the jaws, has an electronic or LCD display to depict the numerals relative to the measurement being taken and it may be read directly in front of the user while the device is in the as-used position taking either type of measurement with the device. 
         [0022]    Additionally provided for further utility and ease of use are wide shoulder portions on each side of the inside measurement jaws (for drum diameter measurements). These shoulder portions have a flat surface substantially parallel to the axis of the elongated member engaging the two sets of jaws. A generally “L” shaped second member extends from each of the shoulder portions. It has been found that the shoulder portions work best if sized at least twice the length of the distal portion of the second member which also extends parallel to the axis of the elongated member to a pointed tip employed for measurements. The long shoulders provide a surface for the user to support the device upon the opposing edges of a brake drum being measured, no matter what the configuration of the edge of the drum. It also allows for the drum to be supported on a table or the floor while the device is employed in the as-used position. 
         [0023]    Also provided are gaps between the distal end and shoulder portion of the jaws. The gaps have an inner sidewall that angles away from the tip of the distal end to allow for engagement of the device around odd shaped brake drums while still supporting the device on the two opposing edges. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0024]      FIG. 1  is a depiction of the disclosed device showing the opposing pairs of members adapted for measurements of brake drums and discs during concurrent viewing of the gauge. 
           [0025]      FIG. 2  depicts the device in the as-used position on a brake drum supported on a floor or other surface showing the wide shoulders supporting the device and display positioned for easy reading. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    The brake disc and drum micrometer device  10  as shown in  FIG. 1 , employs the exterior measuring jaws  12  for measurements of opposing rotor sidewalls of a disc brake rotor, which when properly extended point upward away from the user&#39;s feet or chest when the device  10  is in the hands of the user in the as-used position, taking a rotor thickness measurement. 
         [0027]    Brake drum interior measuring jaws  14  which are employed for measuring a brake drum diameter between opposing walls, as depicted in  FIG. 2 , will point the opposite direction of the exterior measurement jaws  12  when the device  10  is in the as-used position with the user taking a measurement of the interior diameter of a brake drum  13 . 
         [0028]    The digital display  16  is visible directly to the eyes of the user in the as-used position whether the rotor (not shown) is perpendicular to a surface upon which it rests or is in the jaws of a vice. The digital display  16  is also visible directly to the user during a measurement of a drum  13 . 
         [0029]    The digital display  16  provides a calibrated means for axially adjusting either the distance of the exterior measurement jaws  12  or interior measurement jaws  14  from each other and indicating the extent of movement or distance thereof or therebetween from a normal “zero” position which can be set by pressing the zeroing button  23 . Indica on the digital display  16  is always right-side-up to the user during all measurements taken in the as-used position. 
         [0030]    One unique construction aspect of the device  10  allows the drum  13  to be supported on a surface such as a table or floor during this procedure with the opposing sidewall edges  15  of the drum  13  extending away from the support surface. Both the exterior measurement jaws  12  and interior measurement jaws  14  have at least one jaw translatably engaged to an elongated member  27  with each translatably engaged jaw in operative engagement with a digital display  16  which has a zero button  23  to zero out the reading and which will measure the position of each translatable jaw relative to the stationary one of each pair to take and display the measurement of the distance and therefor the thickness of the sidewall  17  or rotor surface (not shown). 
         [0031]    During use in the as-used position in the hands of a user who is biasing the interior measuring jaws  14  against the sidewall  17  interior surface, with the jaws  14  extending downward, the digital display  16  is easily readable right-side-up by the user, just as in use for measuring the rotor with the exterior measuring jaws. Thus, in the as-used position, the digital display  16  is viewable without strain or contortions of the neck or body, while taking the measurements required as is the case with prior art. 
         [0032]    Especially important is the further utility and ease of use which is provided by the wide shoulder portions  18  on each of the interior measuring jaws  14  combined with short pointed distal extensions  21  and notches  24  between the shoulder portions  18  and the distal extensions  21 . The notches  24  are provided by the “L” shape of the jaws  14  where the shoulder portion  18  has an edge  25  substantially parallel to the axis  29  of the elongated member  27  engaging all the components of the device  10 . Both edges  25  of both shoulder portions  18  are substantially the same distance from the axis  29  thereby positioning the device  10  level when supported on the opposing sidewall edges  15  with the heavy drum supported on a surface such as a table or the floor of a garage. 
         [0033]    The shoulder potions  18  thus provide a resting surface for the device  10  which allows the user to rest the device  10  upon the shoulder portions  18  supported by the edges  15  of the sidewall  17  in the as-used position taking a measurement. Because of the extra wide shoulder portions  18 , the device  10  will adapt to just about any configuration of drum  13  some of which can have edges  15  which are extended far from the sidewall  17  and inner surfaces being measured for the diameter of the drum  13 . 
         [0034]    In a particularly preferred mode of the device  10  both interior measuring jaws  14  would be translatably engageable on the member with one being fixedly engaged thereto by the user. This can be done with set screw knobs  11 , or ratchet, or other conventional means to lock the one measuring jaw  14  in position along the member  27 . For large heavy drums  13 , this movement of the fixed jaw  14  will allow the user to a dust the member  27  left or right on the drum  13  to balance the device  10  thereon to alleviate tipping during use. Combined with the wide shoulder portions  18  it renders the device especially easy to use. 
         [0035]    Extensions  19  extend a distance away from a first end of each shoulder portion  18  at an angle substantially perpendicular to the axis  29 . Distal portions having pointed ends  30  extend substantially normal to the extensions  19  and parallel to the axis  29  toward the second end of the shoulder portion  18  forming the “L” shape. The length of the extensions  19  between the edges  25  and the distal extensions  21  define the notches  24  size. An inside wall  31  of each notch  24  angles away from the second end of the shoulder portion  18  which is especially preferred thereby providing an angled surface to the notch  24  to allow it to engage over odd type  15  edges on sidewall  17  which those skilled in the art know can take on widely differing configurations depending on use and manufacturer. 
         [0036]    The shoulder portions  18  supported upon both edges of a drum, also provide a means to level the device  10  and a means to insert the pointed ends  30  of the interior jaws  14  to an equal distance from the edges  15  on which the shoulder portions  18  rest. This insures much more accurate measurements than conventional devices where the user must try and balance the drum  13  while concurrently biasing the jaws  14  and concurrently looking for the digital read out. In such devices the user tends to angle the member  27  while attempting the measurement which tends to lead to inaccurate measurements. Further, employing the shoulders  18  to position the tips  30  at substantially the same position in the drum spaced from the edges  15  in the as-used position, thereby provides increased accuracy with a true and level reading across the diameter of the drum and at a constant depth from the edge  15  at both measurement points on the sidewall  17  contacted by the tips  30 . Conventional devices lacking the large shoulders  18  and pointed tips  30  can easily misread a diameter measurement by mis-positioning to an angled engagement of the member  27  where the tips  30  measure different positions on the drum sidewall  17  and receive an inaccurate measurement. 
         [0037]    As noted, and particularly preferred, to provide for the most accommodation of brake drums  13  and achieve the mount of the shoulder portions  18  on the sidewalls  17  it has been found that shoulder portions  18  from first end to second end which are substantially twice the length of the distal portions  21  from edge to tip  30 , works well in providing a very stable, level positioning of the device  10  on the widest variety of diameter drums  13  from larger truck drums  13  having extremely thick sidewalls  17 , to small car drums  13 , or worn drums  13  having much thinner sidewalls  17 . The large shoulders  18  as mentioned concurrently provide constant equalization of positioning of the tips  30  into the drum  13  on both sidewalls  17  maximizing accuracy of diameter measurements on all types of drums. Additionally, if desired, where the safe diameter measurement of the interior of the sidewalls  17  is not known for turning purposes, such as with non OEM drums  13 , the actual thickness can be determined by employing the exterior jaws  12  to measure the exterior of the sidewall  17  and subtracting the diameter measurement of the interior of the sidewalls  17 . Again, in the as-used position, the numerals of the digital display  16  will be upright and easy to read in such a measurement making the device  10  easy to read, with numerals right-side-up and in plain view in all measurement taken with the device  10 . 
         [0038]    While all of the fundamental characteristics and features of the electronic disc and drum brake gauge have been disclosed and described, with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosure and it will be apparent that in some instance, some features of the invention will be employed without a corresponding use of other features without departing from the scope of the invention as set forth. It should be understood that such substitutions, modifications, and variations may be made by those skilled in the art without departing from the spirit or scope of the invention. Consequently, all such modifications and variations are included within the scope of the invention as defined herein.