Abstract:
A playing card shuffler for shuffling a stack of playing cards with random distribution. The playing card shuffler includes an infeed playing card stack holder supporting an unshuffled playing card stack and discharges playing cards from incremental positions of the unshuffled playing card stack directly to the shuffled card receiver.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of application Ser. No. 08/847,232, filed May 1, 1997 now U.S. Pat. No. 6,019,368, issued Feb. 1, 2000, which is a continuation of Ser. No. 08/228,609, filed Apr. 18, 1994, now U.S. Pat. No. 5,676,372, issued Oct. 14, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an automatic shuffling machine for shuffling decks of playing cards. 
     2. Description of the Prior Art 
     Casinos, cardrooms and other gaming establishments employ many card dealers. The dealers shuffle cards, deal the cards, take bets, and otherwise play the card game. Substantial amounts of the dealers time is spent in just shuffling the decks of cards in preparation for the ensuing card hands. During the time the dealer is shuffling, the game table is inactive and bets are not being placed. From the standpoint of the casino, it is desirable to minimize the time spent in preparing the card decks for additional play. 
     A number of prior art card deck shuffling machines have been invented. Most of the prior automatic shufflers have suffered from various problems. Many are relatively slow and do not help the basic problem encountered by the gaming establishment. Others are relatively complex and thus expensive to build and maintain. 
     Another problem area suffered by both manual and automated shuffling techniques is associated with having concentrated sequences of cards. These concentrations or “slugs” most often occur with respect to cards having a value of 10, such as in playing blackjack. A skilled card counting gambler can take advantage of such card slugs to turn the odds against the casino and in favor of the card counter. Such slugs also indicate the failure of prior art shufflers to in fact effectively rearrange the order of cards in a deck or decks being shuffled. 
     Thus there remains a strong need for improved shuffling machines which can effectively reorder a deck or series of decks. Additionally, there remains a need foran improved automatic card shuffler which is relatively easy to build, operate and maintain. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are described below with reference to the accompanying drawings, which are briefly described below. 
     FIG. 1 is a perspective view showing a preferred shuffler according to the invention. 
     FIG. 2 is a front elevational view of the shuffler shown in FIG.  1 . 
     FIG. 3 is a top view of the shuffler shown in FIG.  1 . 
     FIG. 4 is a cross-sectional view from a top viewpoint illustrating inner components of the shuffler of FIG.  1 . 
     FIG. 5 is a longitudinal sectional view from a front viewpoint illustrating inner components of the shuffler of FIG.  1 . 
     FIG. 6 is a schematic diagram showing functional blocks of the control system used in the shuffler of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8). 
     FIG. 1 shows a preferred playing card shuffler  10  built in accordance with the invention. Shuffler  10  includes a first section  11  and a second section  12 . 
     First section  11  includes a first holder  14  for holding a first or infeed stack  15  of playing cards. The first or unshuffled infeed stack holder  14  advantageously includes a bottom  16 , ejector or end wall  17 , front wall  18 , and back wall  19 . The front and back walls advantageously include manual access cutouts  21  which are U-shaped openings which open to the top and outside. This construction allows a dealer to more easily place cards  20  into the unshuffled stack holder  14 . It also allows manual adjustment of the cards as may be needed in some situations. The openings also allow removal of unshuffled cards from the infeed holder  14  if circumstances justify removal of the stack or other infeed array of playing cards  15 . 
     Ejector or end wall  17  extends from the bottom or floor  16  upwardly to the upper outside surface  23 . The inside or intermediate boundary plane  29  is along the opposite or inward side of infeed holder  14 , in opposed relationship to end wall  17 . The intermediate boundary is relatively open in order to allow unshuffled cards  20  to pass from the first section  11  to the second section  12 , as explained more fully below. Upper portions of the shuffler along intermediate boundary  29  include boundary wall portions  30  (FIG. 2) which connect to intermediate pillars and associated wall structures  32 . The open central regions of the boundary between the first and second sections form a card transfer aperture  35 . Card transfer aperture  35  is defined by bottom or floor  16 , boundary wall portions  30 , and the distance between rollers  130  (see FIG.  4 ). 
     The ejector end wall  17  also preferably mounts an unshuffled infeed stack array playing card detector  190 . Detector  190  can be a segmented capacitive detector which senses the capacitance at various longitudinal locations along the infeed stack holder. This information is then used to make an approximate count of remaining cards for purposes of randomly or otherwise selecting a card to be discharged from the remaining cards available within the infeed holder. 
     The second section  12  includes a second card holder in the form of a shuffled card receiver  41 . Shuffled card receiver  41  has a bottom or second section floor  42 . An outer or end wall  43  extends upwardly from bottom  42 , and connects with a second section top  44 . The second section  12  also preferably has a front wall  46  and a back wall  47 . Receiver  41  also has an interior wall  48  adjacent to the intermediate or boundary plane  29  between the first and second sections of shuffler  10 . 
     Shuffled card receiver  41  holds an outfeed array  51  in the form of a stack of shuffled playing cards  52 . The playing cards rest face-down on floor  42  and are captively positioned between end wall  43 , front and back walls  46  and  47 , and interior wall  48 . The lower portion or zone of the second section forms a collection receptacle forming a part receiver  41 . The upper portions of the second section primarily form the upper zone of the shuffled card receiver. The upper and lower zones are approximately divided along the level of floor  16  of the first section. 
     The shuffled card receiver  41  preferably has continuous walls along the front, back, and outer end of the upper zone to help assure suitable stopping action for playing cards discharged from the first section through opening  35  and into the second section. These upper zone walls are advantageously made from transparent material, such as transparent glass or plastic. A medial frame band  58  extends about the three outer walls approximately along the border between the upper and lower zones of the second section. 
     The front and back walls of the second section are preferably formed with suitable access doors, such as the opposing dual access doors  56  and  57  shown along the front and back walls, respectively. The dual access doors  56 ,  57  are hinged, such as by spring biased hinges  61 , to adjacent portions of the shuffler frame. The dual access doors  56 ,  57  shown define open central sections  63  at the front and back. These central openings allow a card dealer to manually grasp shuffled cards  52  and withdraw them through either the front or back sets of dual access doors  56 ,  57 . 
     FIG. 1 also shows that the first section advantageously has a control panel  67 . Control panel  67  can include an on-off switch  68 , shuffle start switch  69 , and shuffle stop switch  70 . Indicator lights  71  and  72  are used to indicate that the shuffler is shuffling or in a stop or completed mode, respectively. 
     FIG. 2 shows, in phantom lines, two moving cards  74  and  75 . Moving cards  74  and  75  are fed from infeed stack  15  and are discharged laterally into the upper zone of the second section. Card  74  is shown in an upper drift position soon after contact with the second section end wall  43 . Card  75  is shown in a second or lower drift position approaching a resting place upon the top of the outfeed stack  51 . 
     FIGS. 4 and 5 show internal components of card shuffler  10 . The shuffler includes at least one discharger which is used to discharge a card  20  from the infeed stack or other infeed array  15 . As shown, the discharger includes a plurality of ejectors in the form of an ejection array  100 . The ejector array  100  preferably includes a plurality of individual ejector displacers  101 . As shown there are twenty three (23) ejector displacers arranged in a vertical ejector displacer array which is sufficiently tall or appropriately spaced to allow ejection of cards from an infeed stack array containing six (6) standard playing card decks. Each deck has fifty two (52) cards, thus providing a maximum infeed array containing 312 playing cards. This provides ejector displacers at an average card spacing of approximately one ejector per twelve (12) cards. 
     The ejector displacers have ejector displacement heads  102 . The ejector displacement heads  102  preferably have an arched or semicircular outer edge or contact face (see FIG.  4 ). The displacer heads  102  are each connected to an ejector displacer actuator  103 . Actuators  103  are mechanically connected to the head using connection bars  104 . Actuators  103  are preferably small electrical solenoids which can be activated and deactivated. The solenoids are preferably controlled so that activation causes the ejector displacer heads to extend outwardly into an extended position. In the extended position the head engages and displaces a playing card contained within stack  15 . This displacement begins the ejection process. Actuators  103  are also preferably controlled so that deactivation causes the ejector displacer heads to retract. In the retracted position the heads are spaced from the normal position of the infeed card array  15 . 
     FIG. 5 shows that the ejector displacers are preferably mounted upon an ejection carriage  110 . Ejection carriage  110  is mounted for controlled movement relative to the infeed stack of cards. More specifically, the ejection carriage is mounted for movement along a carriage axis  111 . Carriage axis  111  is defined by two guide rods  112  mounted to the frame of the shuffler. The carriage guide rods are preferably placed at space positions, one toward the front of the shuffler and one toward the back. A carriage frame  173  is constructed and mounted to the guide rods for slidable movement thereon in a direction parallel to the carriage axis  111 . 
     Ejector displacer carriage  110  is provided with a carriage position driver  115  which is used to provide controlled movement of the ejector carriage along the guide rods. Carriage driver  115  includes a drive screw  116  which is threadably received by a screw drive carriage connector secured to carriage frame  173 , such as threaded aperture  129 . Drive screw  116  is connected for rotation by a drive screw pulley  117 . A screw drive belt  118  is trained around pulley  117  and a complementary screw drive primary pulley  119 . Screw drive primary pulley  119  is connected to the output shaft of an electrical motor  120  which is the screw drive prime mover. 
     The screw drive motor  120  is preferably a stepper motor or servo-controlled motor capable of accurate positional control. The drive motor also is preferably provided with an angular encoder  122  which has portion connected to the opposite end of the output shaft. The screw drive encoder  122  generates an accurate digital signal indicative of the angular position of the motor. This encoder information is used with a carriage position counter system  123  (FIG. 6) which after being calibrated indicates the linear position of ejector carriage  110 . Data from the resulting carriage position indicator  124  is provided to a central controller  150 . Controller  150  is connected to the screw drive motor  120  to provide a control signal which determines the positional change of the motor needed to provide the desired ejector carriage position used in the next ejection step of the shuffler. 
     The card discharge system of shuffler  10  also preferably includes one or more extractors. As shown, shuffler  10  includes a pair of edge engaging roll extractors  130 . Extractor rolls  130  are driven in counterrotationary relationship by an extractor drive  131 . Extractor drive  131  includes an extractor drive motor  133  which has a rotational output shaft  134 . Output shaft  134  is connected to a counterrotation transmission  136 . Transmission  136  is preferably a gear assembly which has two outputs which receive the drive shafts  135  of extractor rolls  130  therein. This construction allows the extractor rolls  130  to be reliably driven at the same angular velocities but in opposite angular directions. The extractor rolls are spaced and positioned so that the rolls engage playing cards displaced by ejector array  101 . As shown, the extractor rolls engage the displaced cards along the end edges of the cards. The counterrotationary motion of the extractor rolls pulls the displaced card from the infeed stack to thus complete the card discharge or removal process. 
     The extraction subsystem is preferably aided by one or more discharge guides. As shown, shuffler  10  is provided with two ancillary guide rollers  138  along both sides. Guide rollers  138  are preferably passive rollers without any drivers but are mounted for free rotation. 
     FIG. 4 shows that shuffler  10  is also preferably provided with two types of card removal resistors or counters  141  and  142  which resist or counteract removal of cards from the infeed stack. The removal resistors can be static or dynamic. If static then the resistors can simply be elongated resilient pads with faces angled to engage the corners of the discharging cards. Static pad resistors (not shown) can be made from a foam or other suitable material. 
     As shown, the shuffler includes dynamic removal resistors  141 . Dynamic resistors  141  are preferably rotating cylindrical members covered with flailing fibers, such as synthetic nylon bristle fibers. The resistors  141  are mounted adjacent to the forward corners of the infeed stack. Resistors  141  are actively driven in counterrotating directions opposing discharge of cards. The rotational motion is advantageously provided by additional output receptacles formed in gear unit  136 . The dynamic resistors serve to help prevent unintended ejection of unselected cards from stack  15 . The greatest risk of unintended ejection is associated with the cards adjacent to the card being ejected. This risk of unintended ejection is caused by surface friction between the adjacent card and the card being engaged and displaced by the activated ejector displacer head  102 . Some risk also exists that the ejection head  104  may strike two cards. 
     The removal or ejection resistance subsystem also preferably includes controllable active card removal resistors  142 . Removal resistors  142  are mounted along the front and back of the infeed stack holder  14 . The active removal resistors  142  include longitudinal strips  146  which preferably have padded contact faces  143  mounted thereon. Padded contact faces  143  engage the edges of the playing cards of the infeed stack. Piezoelectric or other suitable drivers  144  are mounted between the frame of the shuffler and the longitudinal strips  146 . The active resistor drivers serve to controllably move the active resistors inwardly and outwardly. When moved inwardly into contracted positions, the co-acting contractionary resistors function to squeeze or grasp the infeed stack. When moved outwardly into expanded positions, the active resistors function to release the cards contained in the infeed stack. The active removal resistors are controlled to engage and grasp the infeed stack during the ejection process in order to reduce the risk of removing multiple cards rather than the single card which is intended to be ejected. Resistors  142  also serve to jostle and straighten the cards of the infeed stack. 
     FIG. 6 shows a diagrammatic or schematic view of a preferred control system used in shuffler  10 . The control system includes a central controller  150  which can be selected from a variety of suitable electronic controllers. Central controller is electrically connected to receive signals from power switch  68 , start switch  69 , and stop switch  70  on control panel  67 . Controller  150  provides signals to run indicator  71 , and stop indicator  72  mounted on the control panel  67 . 
     Controller  150  is connected to screw drive motor  120  to provide control signals thereto which indicate action which should be taken by the screw drive to move the ejector carriage  110 . Encoder  122  sends signals to carriage position counter.  123 , which in turn signals central controller  150  concerning the position of the ejector carriage. Encoder  122  and counter  123  provide a carriage position indicator  124 . 
     Controller  150  is also connected to operate extraction roller drive motor  135 . Additionally, controller  150  is connected to the piezoelectric drives  144  for the active resistors  142 , to provide intermittent operation thereof as described above. Still further, controller  150  is connected to read the approximate number of cards in the infeed array using the infeed card detector  190 . 
     The invention further includes novel methods for performing automated shuffling of playing cards. The methods include forming an unshuffled array of playing cards which are to be shuffled. The forming of the unshuffled array is advantageously done by forming a stack of playing cards. The forming of the unshuffled array is done in such a manner so as to provide playing cards which are in face-to-back relationships throughout the unshuffled array. Face-to-back relationship refers to the standard condition in which playing cards are sold wherein the face of one card is adjacent to the back of the next adjacent card. 
     The novel methods further include holding the unshuffled array in an unshuffled array holder. This is advantageously accomplished by holding the infeed stack  15  in the infeed stack holder  14 . Holding can further be enhanced by grasping the infeed stack array using the active resistors  142 . Such grasping is accomplished by contracting opposing complementary resistors against edges of the playing cards. 
     The methods further include selectively discharging playing cards from the unshuffled infeed array. The playing cards are discharged from various discharge positions within the array. The discharge positions are most preferably selected in a random fashion from the available array positions left in the stack at the time of discharging. 
     The selective discharging of playing cards from various positions within the unshuffled card array, also includes selecting a playing card to be discharged. The selecting process is believed capable of being performed under a number of numerical selection processes. It is believed most preferable to perform the card selecting step in a random manner. This random selection is most ideally performed by the central processor  150 , appropriately programmed to also perform a random number generation process. The random number generating process is preferably performed in such a manner that the random number is generated with respect to the number of playing cards remaining in the infeed stack. This is determined by the infeed stack array playing card detector  190 . 
     The discharging process is also preferably performed by including an ejecting and displacing of playing cards by extending an ejection head against an edge of the playing card and forcing the card being ejected and displaced. The ejection head performs an inserting action between the playing cards which are adjacent to the card being ejected. The forcing performs a displacing action upon the selected card aligned with the ejection head which was extended. 
     As shown, the discharging process further preferably includes extracting playing cards from the infeed array. The extracting step is preferably an adjunct to an initial partial ejection or displacement using an activated ejection head  102 . Extracting is advantageously accomplished by engaging edges of the selected displaced card using a movable extractor. The step is more preferably accomplished by rolling the edges of the selected card using an extraction roller or rollers. Extraction rolling is most preferably accomplished by rolling the card edges using opposed counterrotating extraction rollers which are rotating at the same angular velocity. 
     The methods of the invention can further be conducted so as to include guiding the card being discharged. The guiding action can be performed by the passive guide rollers  138  and driver extraction rollers  130 . 
     The novel methods further include receiving discharged playing cards in a shuffled card receiver. This is preferably accomplished by discharging the cards against a stop or rebound surface to perform a stopping and aligning functions. This causes the discharged cards to effectively stop at a desired horizontal position. The discharged playing cards also preferably function by dropping within a shuffled card receiver to form shuffled card stack array  51 . 
     The methods of this invention can further include removing shuffled playing cards from the shuffled card array by removing such cards from the receiver  41 . In shuffler  10 , this is done by manually grasping a group of cards contained in the outfeed stack and withdrawing them through the opening defined by swinging doors  56  and  57 . 
     In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.