Abstract:
An accessory for aligning items parallel to the measurement axis of an outside micrometer, comprising: 
     a platform, having a flat surface bisected by a depressed channel, the platform including a first cylindrical ring disposed at one end of the channel, the platform also including a keyed cavity beneath the channel, 
     a second cylindrical ring, connected to a keyed rod, the rod being slidably installed into the keyed cavity, whereby the first and second cylindrical rings are maintained coaxial and parallel to the platform surface and the keyed channel, 
     a spring, retained in the keyed cavity by the keyed rod, exerting outward force on the rod and attached ring, maintaining them in a slidably extended position, limited by protruding wedges in the keyed cavity.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     BACKGROUND 
     1. Field of Invention 
     This invention relates to accessories for a micrometer, specifically to those accessories which are attachable to, and detachable from a conventional outside micrometer. 
     2. Description of Prior Art 
     Attachments for a conventional outside micrometer are commonly used in the manufacturing and machining industries. The general function of these attachments is to facilitate accurate measurement taking of specific part or material shapes. 
     There are two types known to this inventor. Both types modify the interface between the micrometer and the item being measured. The first type mounts directly over the micrometer spindle or anvil measuring faces and is commonly retained to them by a rubber attachment boot or sleeve apparatus. These are commonly known as anvil and spindle attachments. As found, all of these attachments add a length to the anvil or spindle, which must be subtracted from the measurement. None have been found to create a platform, surface, or “table” to support or align the measured item. 
     The second type consists of specialty micrometers which employ interchangeable spindles or anvils of various configuration. None of them have been found to create a table to support or align the measured item. Micrometer stands might be considered add-on accessories, however they support the micrometer itself, and again do not support or align the measured item. 
     There are only two micrometer-type measuring tools known to this inventor which do support or align the measured item. One is known as a “wire micrometer”. It is a specialty micrometer, not an add-on accessory for a conventional micrometer. The table of a wire micrometer is a non-removable part of the micrometer itself. The table configuration greatly reduces the clearance to measure most common items. There is no clearance loop, or “throat” between the spindle and the anvil, as there is on a conventional micrometer. The inability to measure most common items, and the prohibitive expense of this specialty tool, tends to limit sales to specific industries such as the wire forming industry. 
     In addition, wire micrometers are not easily held and utilized in one hand. The throat loop of a conventional micrometer is normally grasped between the tip of the pinky finger and the palm of the hand. This allows the micrometer to be positively retained, while the measuring adjustment (barrel rotation) is accomplished with the thumb and index finger. Therefore, the normal operation of a conventional micrometer is one-handed, allowing the other hand to hold the item being measured. Although a wire micrometer may be held in one hand, there is no throat loop to be grasped, thus it may easily be dropped. Another disadvantage of the wire micrometer table is that it is narrow, generally about 13 mm. wide. It is difficult to stabilize many measured items on this small surface area. The normal measuring range is only zero to 13 mm. or less, compared to the conventional micrometer measuring range of zero to 25.4 mm. The table is also not free to rotate about the measurement axis. To measure a stationary item, the wire micrometer itself must be positioned so that the “table” rests flat against the item. This often requires the scale or digital readout to be facing at an angle away from the operator. 
     The other type of micrometer found to incorporate a table surface on which the measured item may be supported is known as a bench micrometer. A bench micrometer has an integral heavy base. It is not a hand held tool. It is designed to rest stationary on a workbench, therefore the object to be measured is brought to it. The table surface of a bench micrometer is an integral part of the tool, not an attachment. Also as found, the table surface does not have rotational self-aligning capability. 
     U.S. Pat. No. 5,463,818 to Hughes (1994), and U.S. Pat. No. 5,287,631 to Stade (1991), disclose micrometer-type measuring tools with tables on which to rest the measured item. However, they are also bench type micrometers, not attachments to a conventional micrometer. 
     SUMMARY 
     The object of the present invention is to aid in the alignment of certain items between the measuring faces of a conventional micrometer. The object is also for the present invention to be quickly and easily attached to, and removed from the micrometer. 
     Objects and Advantages 
     Accordingly, several objects and advantages of the preferred embodiment of the present invention are: 
     (a) to create a table surface aligned parallel to the measurement axis of a conventional micrometer on which to position an item between the measuring faces of the micrometer. 
     (b) to attach to a micrometer by radial capture of the anvil and spindle. This allows the table surface of the present invention to rotate axially around the measurement axis, yielding axial self-alignment capability to items in a fixed position. 
     (c) to not affect or alter the interface between the micrometer measuring faces and the measured item. There is no add-on item whose length must be subtracted from the measurement. 
     (d) to provide an attachment mechanism allowing rapid installation and removal from the micrometer without reducing the measurement range. 
     (e) to not affect the portability or normal one-handed operation of a conventional micrometer. 
     (f) to provide a table surface of adequate width and length to properly support flat, thin profile items within the entire micrometer measurement range. 
     (g) to provide a depressed V-groove in the table surface so as to align and support cylindrical items parallel to the measurement axis. 
     (h) to be manufactured of molded plastic, of a durometer softer than the micrometer measuring faces and body, so as to eliminate the possibility of damage to them. 
     Further objects and advantages of the present invention will become apparent from a consideration of the drawings and ensuing description. 
    
    
     DRAWING FIGURES 
     For a fuller understanding of the nature and objects of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which: 
     FIG. 1 is a perspective view of the preferred embodiment of the clip-on micrometer table of the present invention. 
     FIG. 2 is an exploded perspective view of the components of the preferred embodiment of the clip-on micrometer table of the present invention. 
     FIG. 3 is a side elevation view of the preferred embodiment of the clip-on micrometer table of the present invention. 
     FIG. 4 is a front elevation view of the preferred embodiment of the clip-on micrometer table of the present invention. 
     FIG. 5 is a bottom elevation view of the preferred embodiment of the clip-on micrometer table of the present invention, with the spindle clip shown removed therefrom. 
     FIG. 6 is a perspective view of an alternate embodiment of the present invention with a rectangular interface configuration. 
     FIG. 7 is a perspective view of an alternate configuration of the present invention further including a fence integrated to the table surface. 
     FIG. 8 is a perspective view of an alternate configuration of the present invention further including pegs attachable to the table surface. 
     FIG. 9 is a perspective view of the preferred embodiment of the clip-on micrometer table of the present invention as installed to a conventional micrometer 
     
       
         
               
             
               
               
             
               
             
               
               
             
               
             
               
               
             
           
               
                   
               
               
                 Reference Numerals In Drawings 
               
               
                   
               
             
             
               
                 (Preferred Embodiment: FIGS. 1-5) 
               
             
          
           
               
                 20 Clip-on Micrometer Table 
                 22 platform 
               
               
                 24 spindle clip 
                 26 anvil mount ring 
               
               
                 28 spindle mount ring 
                 30 table surface-left side 
               
               
                 32 table surface-right side 
                 34 spring 
               
               
                 36 interface cavity 
                 38 platform-front surface 
               
               
                 40 interface cavity-bottom surface 
                 42 slot side-wall surface-left side 
               
               
                 44 slot side-wall surface-right side 
                 46 interface slot 
               
               
                 48 V-channel surface-left side 
                 50 V-channel surface-right side 
               
               
                 52 upper slot end surface 
                 54 lower slot end surface 
               
               
                 56 snap-retention feature-left side 
                 58 snap-retention feature-right side 
               
               
                 64 locking tab 
                 66 rod end surface-back 
               
               
                 68 rod surface-front 
                 70 platform surface-back 
               
             
          
           
               
                 (Alternate Embodiments: FIGS. 6-8) 
               
             
          
           
               
                 72 rectangular interface platform 
                 74 rectangular interface spindle clip 
               
               
                 76 fenced platform 
                 78 spring tensioned fence 
               
               
                 80 perforated table surface 
                 82 peg(s) 
               
               
                 84 peg snap retention feature 
               
             
          
           
               
                 (Preferred Embodiment - As Installed: FIG. 9) 
               
             
          
           
               
                 86 Conventional Outside 
                 90 micrometer spindle 
               
               
                 Micrometer (Prior Art) 
                 94 micrometer barrel 
               
               
                 88 micrometer anvil 
               
               
                 92 micrometer frame “throat” loop 
               
               
                 96 micrometer body 
               
               
                   
               
             
          
         
       
     
    
    
     DESCRIPTION 
     FIGS.  1 - 5 —Preferred Embodiment 
     In FIGS. 1-5, the preferred embodiments of the clip-on micrometer table of the present invention are depicted. By referring to these drawings, along with the following detailed disclosure, the construction and operation of the present invention can be best understood. However, it is also to be understood that the present invention can be employed in alternate configurations not depicted herein. The following detailed disclosure as well as the associated drawings are provided for explanatory purposes and are not intended to limit the scope of the present invention. 
     As shown in FIGS. 1 and 2, the preferred embodiment of the clip-on micrometer table  20  comprises a platform  22 , and a cooperating spindle clip  24  which is held aligned and captive to platform  22 . Platform  22  and spindle clip  24  establish a fixed parallel relationship between the axis of anvil mount ring  26  and spindle mount ring  28 , (the measurement axis), and support, or table surfaces  30  and  32 . Table surfaces  30  and  32  are substantially flat and in-plane with each other, comprising an area approximately 23 mm. long by 30 mm. wide. Table surfaces  30  and  32  are offset from the measurement axis approximately 0.5 mm. 
     Platform  22  comprises flat table surfaces  30  and  32 , anvil mount ring  26 , and cylindrical interface cavity  36 . Anvil mount ring  26  is connected to back surface  70  of the main body of platform  22  and is contiguous with platform  22 . Table surfaces  30  and  32  are parallel to the axis of both anvil mount ring  26 , and interface cavity  36   
     As depicted in FIGS. 2-4, interface cavity  36  extends from platform front surface  38  to interface cavity bottom surface  40 . Slot side-wall surfaces  42  and  44  form interface slot  46  which is integral with and bisected by interface cavity  36 . V-channel surfaces  48  and  50  are depressed on an angle from table surfaces  30  and  32  extending to interface slot  46 . Slot  46  extends from platform front surface  38  to upper slot end surface  52  above cavity  36 , and from platform front surface  38  to lower slot end surface  54  below cavity  36 . 
     As best depicted in FIG. 5, within interface slot  46  below cavity  36 , are wedge-shaped snap retention features  56  and  58  which protrude from slot side-wall surfaces  42  and  44 . 
     As shown in FIG. 2, the preferred embodiment of spindle clip  24  is comprised of rod  60  and spindle mount ring  28 , connected axially parallel by web  62 . Locking tab  64  protrudes from rod  60  opposite web  62 . Locking tab  64 , rod  60 , and web  62  form a keyed (male) configuration, which is inserted into the (female) configuration described by cylindrical cavity  36  and slot  46 . This keyed insertion of spindle clip  24 , into platform  22  is of sufficient clearance to allow axial slip without tangential cocking. The keyed interface configuration also does not allow spindle clip  24  to rotate. 
     As shown in FIGS. 3 and 5, spring  34  is held captive in cavity  36  providing outward tension between interface cavity bottom surface  40  and rod end surface  66 . When assembled, spindle clip  24  is held captive to platform  22  by the interface of locking tab  64 , and snap retention features  56  and  58 . Spindle clip  24  may be forced against outward tension supplied by spring  34 , by applying pressure between rod front surface  68  and platform back surface  70 . This allows compressive axial movement of spindle clip  24  in relationship to platform  22 . The limit of this movement is the point of interference between platform front surface  38  and spindle mount ring  28 . Before reaching the point of interference, adequate clearance is obtained to attach the present invention to a conventional micrometer. At all times, a parallel in-line relationship is maintained between the measurement axis, table surfaces  30  and  32 , and V-channel surfaces  48  and  50 , and cylindrical cavity  36 . 
     FIGS.  6 - 12 —Alternative Embodiments 
     There are various possibilities with regard to the construction and configuration of the present invention. 
     FIG. 6 depicts a configuration of the present invention incorporating a rectangular interface platform  72  and a rectangular interface spindle clip  74  to reduce the overall thickness of platform  72 . 
     FIG. 7 depicts a spring tensioned fence  78  slidably attached to fenced platform  76 . Fence  78  maintains a perpendicular attitude to the measurement axis throughout its range of movement. 
     FIG. 8 depicts perforated table surface  80  incorporating through holes in a grid pattern. Separate pegs  82  may be inserted into any combination of holes. Peg snap retention feature  84  retains pegs  82  to table surface  80 . 
     FIG. 9 depicts the preferred embodiment of clip-on micrometer table  20  as attached to a conventional micrometer  86 . The components of a conventional micrometer  86  discussed in this description are: 
     
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 88 micrometer anvil 
                 90 micrometer spindle 
               
               
                   
                 92 micrometer “throat” loop 
                 94 micrometer barrel 
               
               
                   
                 96 micrometer body 
               
               
                   
                   
               
             
          
         
       
     
     Advantages 
     From the description above, a number of advantages of the clip-on micrometer table of the present invention become evident: 
     (a) The present invention provides a support surface on which an item to be measured is quickly and easily aligned to a micrometer&#39;s measurement axis. 
     (b) The present invention incorporates an axial self-aligning function to measure items which are in a fixed position. 
     (c) No alterations to a micrometer or measurement reading are required. 
     (d) Attachment to and detachment from a micrometer may be accomplished in less than five seconds. 
     (e) As installed, the present invention is self-retaining to a micrometer. 
     (f) The present invention does not affect the portability, operation, or range of measurement, of a micrometer it is attached to. 
     (g) The configuration of the present invention is such that high volume manufacturing by injection molding plastic may be accomplished, producing accurate components at a low per-part cost. 
     (h) As manufactured of molded plastic material the present invention cannot cause damage to a micrometer. 
     (j) The present invention may be alternately configured to reduce manufacturing cost, modify the mounting features, or modify the table configuration for better item support. 
     Operation—FIGS.  1 - 5 —Preferred Embodiment 
     The present invention is utilized as attached to, and functioning in cooperation with a conventional micrometer  86  (FIG.  9 ). Attachment procedure is as follows: 
     Adjust micrometer spindle  90  to a position of approximately 1 to 2 mm. protrusion from micrometer body  96 . 
     The present invention is compressed between thumb and forefinger by applying pressure between front rod surface  68  and platform back surface  70 . 
     Anvil mounting ring  26  is positioned over micrometer anvil  88 . 
     Spindle mounting ring  28  is aligned to, and positioned over protruding micrometer spindle  90 . 
     Spring tension is relieved. 
     The present invention is now self retaining to the micrometer. Normal operation of the micrometer is unaffected. Reverse attachment procedure for removal. 
     The present invention as attached to a micrometer, achieves table surfaces  30  and  32  with integral V-channel surfaces  48  and  50 , retained in a position parallel and coaxial to the micrometer measurement axis. As positioned flat on the table surfaces, certain items such as blade, strip, or shim stock are supported parallel to the measurement axis between the micrometers anvil and spindle measuring faces. The integral V-groove channel supports cylindrical items such as rings and die punches, and also allows clearance for spindle movement. The table surface and V-groove channel assist in supporting these various measured items in a manner whereby they do not get cocked at an angle between the anvil and spindle measuring faces. This support facilitates rapid alignment and measurement accuracy throughout the entire measurement range of the micrometer. 
     The present invention is attached to the micrometer by cylindrical capture. Anvil mount ring  26  slip-fits over the cylindrical micrometer anvil  88 , and spindle mount ring  28  slip-fits over the cylindrical micrometer spindle  90 . This allows the present invention to rotate around the measurement axis. Throughout rotation, the table surface and V-groove channel are maintained parallel and coaxial to the measurement axis. This rotation enables the present invention to be axially self-aligning to items which are in a fixed position, such as a blade which is installed in a cutting machine. When pressed against these fixed items, the table surface of the present invention will rotate axially so as to align itself flat against them. While against the table surface, the fixed item may be more accurately measured. 
     The table surface is offset from the measurement axis by approximately 0.5 mm. This offset has been found to counteract the tendency of an item to walk across the table while being measured, due to contact with the rotating spindle face. 
     The compact construction of the present invention allows sufficient clearance to the micrometer “throat”  92  for normal one-handed measurement taking, as previously described. 
     Operation—FIGS.  6 - 12 —Alternate Embodiments 
     As shown in FIG. 6, the interface of rectangular interface platform  72  and rectangular interface spindle clip  74 , reduces the thickness of the present invention. This compact embodiment increases grasping clearance to the micrometer throat  92 . The method of operation is the same as with the preferred embodiment. 
     FIG. 7 illustrates fenced platform  76  incorporating slidably installed spring tensioned fence  78 . As the measured item is positioned flat on the surface of fenced platform  76 , it is forced against spring tension exerted by fence  78 . Fence  78  is then allowed to pre-load the measured item against the micrometer anvil  88 . Pre-loading helps to secure the item for ease of measurement taking. 
     FIG. 8 depicts perforated table surface  80 , configured with a grid pattern of through holes. Independent pegs  82  may be snapped into or removed from the holes by elastic deformation of peg snap-retention feature  84 . As installed, pegs  82  serve to consistently align similarly configured items in the same location relative to the micrometer measuring faces. Thereby, a certain aspect or profile is measured consistently item to item. Pegs  82  may be arranged on the table surface in any combination of locations to accommodate item profiles. 
     Conclusion, Ramifications, and Scope 
     As is apparent from the entire foregoing discussion, the clip-on micrometer table of the present invention may be used to quickly position an item parallel to the measurement axis of a micrometer, whereby an accurate measurement may be taken throughout the entire measurement range. Many items with shapes that are difficult to align for measurement, are easily supported in the optimum position for accurate measurement. In addition, the axial self-aligning feature acts to align the micrometer to non-movable items. Furthermore, the clip-on micrometer table of the present invention has additional advantages in that: 
     it can be attached to and detached from a conventional micrometer in less than five seconds, and is self-retaining when attached. 
     it does not affect the measurement range, the measurement reading, the portability, or the normal operation of a micrometer. 
     it may be configured in a variety of alternate table profiles to accommodate different item shapes. 
     it may be configured with alternate mechanisms to reduce its overall size, increasing micrometer grasping clearance. 
     it may incorporate table features which pre-load and hold the item in position for measurement. 
     it may incorporate table features which consistently align similarly shaped items for accurate comparative measurement. 
     it is configured to allow high volume manufacturing by injection molding plastic. 
     it will not cause damage to a micrometer due to its manufacturing from softer material. 
     Although the description above contains many specific details, these should not be construed as limiting the scope of the present invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. For example, the size may be changed for use with larger or alternately configured micrometers, etc.; or it may be textured or rubber coated to reduce possible slipping of an item on the table surface, etc.