Patent Document

BACKGROUND  
       [0001]     Optical bar code scanners typically include a mirrored spinner. It would be desirable to provide an apparatus for rotating a mirrored spinner.  
       SUMMARY  
       [0002]     An apparatus for rotating a mirrored spinner is provided.  
         [0003]     The apparatus includes a first axle which rotates about a first axis of rotation, and a second axle for mounting the mirrored spinner to the first axle, wherein the second axle rotates the mirrored spinner about a second axis of rotation. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]      FIG. 1  is a block diagram of a bar code scanner;  
         [0005]      FIG. 2  is a view of an example bar code scanner;  
         [0006]      FIGS. 3   a - c  are views of an example scan engine;  
         [0007]      FIGS. 4-6  are views of additional examples of scan engines; and  
         [0008]      FIG. 7  is a view of an example scan engine with an additional degree of freedom. 
     
    
     DETAILED DESCRIPTION  
       [0009]     With reference to  FIGS. 1 and 2 , an example bar code scanner  10  includes laser  12 , mirrored spinner  16 , pattern mirrors  18 , collector  20 , detector  22 , and control circuitry  24 .  
         [0010]     Laser  12  produces a laser beam. Mirror flat  26  ( FIG. 2 ) directs the laser beam towards mirrored spinner  16 .  
         [0011]     Mirrored spinner  16  directs the laser beam to pattern mirrors  18 . Mirrored spinner  16  further directs light reflected from item  30  to collector  20 . Mirrored spinner  16  is rotated by drive assembly  34 . Mirrored spinner  16  is shown with may have any number of mirrored facets. Four facets are illustrated in  FIG. 1 .  
         [0012]     Mirrored spinner  16  and drive assembly  34  form a scan engine having two axes  36  and  40  of rotation to essentially rotate scan volume  38  about axis  36  ( FIG. 2 ). The scan engine produces a hemispherical shaped scan volume  38 , which is larger than a comparable wedge shaped scan volume of a conventional single axis scan engine. In one embodiment, first axis  36  is substantially orthogonal to second axis  40 , however, other angles between axes  36  and  40  are also envisioned.  
         [0013]     First axis  36  is rotated by motor  50 . In an example embodiment, motor rotates first axis  36  as high as about 1200 RPM. Drive assembly  34  produces an example speed of rotation about second axis  40  of as high as about 19,200 RPM (16:1 ratio). Other speeds are envisioned as motor technology improves. Synchronized rotation of axes  36  and  40  results in a static scan pattern at the scanner aperture.  
         [0014]     Pattern mirrors  18  produce scanning light beams for scanning bar code  32  on item  30 . Pattern mirrors  18  further collect light reflected from item  30  and direct the reflected light to mirrored spinner  16 .  
         [0015]     Collector  20  collects the reflected light from mirrored spinner  16 .  
         [0016]     Detector  22  converts the reflected light into electrical signals based upon the intensity of the reflected light.  
         [0017]     Control circuitry  24  controls operation of laser  12  and motor  34  and decodes bar code information contained within the electrical signals received from detector  22 .  
         [0018]     With reference to  FIGS. 3   a  and  3   b , an example embodiment of drive assembly  34  is illustrated.  
         [0019]     With reference to  FIGS. 3   a - c , drive assembly  34  includes motor  50 , shaft  52 , spinner assembly  54 , and spinner rotation mechanism  55 .  
         [0020]     Motor  50  is mounted in stationary fashion and rotates shaft  52 .  
         [0021]     Shaft  52  rotates spinner assembly  54  about axis  36 .  
         [0022]     Spinner assembly  54  includes yoke  60 , axle  62 , bearings  66 , balance plates  68 , and facets  69 .  
         [0023]     Yoke  60  attaches to and rotates with shaft  52 . Opposite arms  61  of yoke  52  retain axle  62 .  
         [0024]     Axle  62  rotates about axis  40 . Mirrored spinner  16  rotates with axle  62 .  
         [0025]     Bearings  66  are located in yoke  60 . Shaft  52  rides on bearings  66 .  
         [0026]     Balance plates  68  balance rotation of mirrored spinner  16 .  
         [0027]     Facets  69  are mirrored to reflect scanning light beams and reflected light. The orientations of facets  69  vary around spinner  16  so as to direct the scanning light beams in various directions. Eight facets  69  are shown in  FIG. 3   b.    
         [0028]     Spinner rotation mechanism  55  includes cylinder  56 , magnet  64 , and ring of magnets  58 .  
         [0029]     Cylinder  56  is mounted in stationary fashion about axis  36 .  
         [0030]     Ring of magnets  58  is mounted to cylinder  56 .  
         [0031]     Magnet  64  is mounted to axle  62  and interacts with ring of magnets  58  to rotate axle  62  as yoke  60  rotates with shaft  52 . In this embodiment, magnet  64  is mounted with the poles perpendicular to axle  62 . Other configurations and angles are also envisioned. For example, axle  62  may be extended and another magnet  64  may be mounted to an opposite end of axle  62  from the other.  
         [0032]     With reference to  FIG. 3   c , north and south magnets  70  and  72  alternate around ring of magnets  58 . Other configurations of magnets  70  and  72  are also envisioned.  
         [0033]     As motor shaft  52  rotates spinner assembly  54 , attractive and repulsive forces from ring of magnets  58  act on magnet  64  on axle  62  to cause rotational torque on axle  62 . In one example, ring of magnets includes nine pairs of north-south magnets  70  and  72 , and each pair of north-south magnets  70  and  72  causes one revolution of axle  62 , resulting in a spinner rotational speed about 9 times faster than the rotational speed of shaft  52 .  
         [0034]     With reference to  FIG. 4 , an alternate embodiment includes driver mechanism  55   b  which relies on friction or gear teeth to rotate mirrored spinner  16 . Instead of ring of magnets  58 , cylinder  56  includes a friction pad or gear teeth ring  80 . A friction embodiment envisions friction pad  80  interacting with axle  62  through friction to rotate axle  62 . A gear embodiment envisions gear teeth ring  80  interacting with axle  62  through gear  82  to rotate axle  62 .  
         [0035]     With reference to  FIG. 5 , an alternate embodiment includes drive rotation mechanism  55   c  which relies on a second motor  92 . In one embodiment, second motor  52  receives electrical power through slip ring  90  which frictionally contacts stationary electrical terminals as it rotates about axis  36 . In other alternative embodiments, power to second motor  92  may be provided through conductive bearings, a battery, a capacitor, a solar cell, or a fuel cell as part of spinner assembly  54 .  
         [0036]     With reference to  FIG. 6 , an alternate embodiment includes drive rotation mechanism  55   d  which relies on pressurized air to rotate mirrored spinner  16 . Drive rotation mechanism  55   d  includes pressurized air source  100 , nozzle  102 , and fan blades  104 . Pressurized air source  100  is delivered through motor shaft  52  and rotating nozzle  102 . Nozzle  102  directs pressurized air at fan blades  104  arranged around one of balance plates  68 . Nozzle  102  rotates on hollow slow motor shaft  52  so it always stays aligned with spinner  16 .  
         [0037]     With reference to  FIG. 7 , an alternate embodiment envisions movement of the scan pattern by adding an additional degree of freedom to create a dynamic scan pattern. In this example embodiment, a rolling movement of the scan pattern is accomplished by rotating motor  50  or cylinder  56  about axis  36 . Other degrees of freedom could also be added to the scan engine to move the pattern in other directions such as in azimuth or elevation.  
         [0038]     The scan engine of  FIG. 3A  is used for purposes of illustration, as other scan engines may also be rotated in this way. The embodiment adds motor  110 , sprocket  112 , and gear  114 . Motor rotates sprocket  112 , which engages gear  114 . Gear  114  is rigidly fixed to cylinder  56 , causing it to rotate about axis  36 . An example motor speed is about 60 RPM. Motor speed may be continuous or vary. Motor speed may also oscillate.  
         [0039]     While a gear arrangement is shown, other ways of rotating cylinder  56  are also envisioned, including belts, or more magnets.  
         [0040]     Although particular reference has been made to certain embodiments, variations and modifications are also envisioned within the spirit and scope of the following claims.

Technology Category: g