Abstract:
A marketing system and method for customer specific promotions providing a yield management tool for casino resort properties to more effectively manage entertainment related assets and inventories to build new and existing customer business. The system provides a convenient method for consumers to realize promotional incentives proportional to their player wagering status at a broader level within the casino resort industry while simultaneously delivering casino resort operators a cost effective tool to maximize the value of their assets. The system utilizes register user supplied player wagering and comp data, and historical waging data on said registered users collected by the system from participating casino resort properties to build a broad-based casino customer database defining the waging profiles of individual gaming customers. Built on the foundation of this industry-wide database resource, the system&#39;s electronic transaction platform construction provides casino resort properties a facility to interact directly with gaming oriented customers to present compelling, customer specific promotional offers at the point of purchase where said customers make casino resort air/room travel plans and review purchase decision options.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims the benefit and priority of U.S. Provisional Application for Patent Ser. No. 60/670,069 filed on Apr. 11, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Over the past thirty years America has evolved from a place where gambling was a relatively rare activity with casinos operating only in the Nevada, and a few states operating lotteries, and pari-mutuel gambling on a smallish scale, into a nation where legalized gambling, in one form or another, is one of the more popular leisure activities. The amount spent on gambling compared to all other leisure activities is particularly noteworthy. In 2004, more than ten percent of the over $650 billion Americans paid for leisure goods, services and activities was spent on gambling, not including monies spent by gamblers on hotels, food, transportation and other related expenses. In terms of “destination leisure” (e.g., spectator sports, cruise ships, theme parks, concerts, etc.), “destination” gambling accounts for more than one-third of total market revenues. And of all gambling categories, casino gambling is the most popular, generating over 50% of the total commercial gambling revenues for all categories.  
         [0003]     As the casino resort and gaming industry has grown and matured, the use of entertainment to drive gaming revenue has continued to be the market&#39;s principal proven formula for success. In Las Vegas, entertainment (non-gaming) related revenue now accounts for over 40% of total casino gross revenues. Las Vegas&#39; successful entertainment driven formula is the model for other major casino resort destination markets striving to increase their potential.  
         [0004]     Two factors influencing casinos decisions related to management of their entertainment assets and investments are the (i) fixed cost, and (ii) perishable nature of related inventory. Entertainment products are generally characterized by fixed versus variable cost based investments (i.e., facilities, maintenance, entertainer fees, etc.) and corresponding inventory is predominantly “perishable”. Therefore, many important expense levels cannot be readily adjusted downward if necessary to meet lower than average or projected sales levels, and if an inventory allotment for any given day is not sold (e.g., hotels room, seat at a boxing match, etc.) related revenue potential is lost and can not be recovered.  
         [0005]     As a result of the popularity of casino gaming, the number and size of casino resorts has seen rapid and continued growth. Similarly competition between casino resorts to attract and retain gaming customers has intensified. Casino sponsored entertainment such as shows, events, and night clubs, is the most popular method used by casinos to attract gaming customers, and “comps” are one of the most widely recognized promotional tools to use entertainment assets to successfully build and retain valued gaming business.  
         [0006]     “Comp” is the casino industry term for special promotions, e.g., free rooms or upgrades, tickets to events, complimentary food and beverages, provided to customers to foster goodwill and build customer loyalty. The level of comps a casino may provide to a customer is generally based on an individual players rating or value to a casino, as typically determined from the customer&#39;s historical level of play or wagering.  
         [0007]     Casino rating systems utilize various methods to track players wagering history. Related historical data is utilized to determine such information as a player&#39;s average wager, amounts wagered during an average gaming session, type of games preferred, frequency of visits per year, etc. This data provides casinos with the ability to reward individual customers with comps that are proportional to each customer&#39;s unique wagering status. With accurate historical waging data, casinos can make promotional comp commitments more quickly to their customers to attract or retain their business and prevent the danger of (i) over spending based on the customer&#39;s actual value to the casino, or (ii) failing to provide treatment and accommodations for valuable customers at levels to which the customers are accustomed or entitled.  
         [0008]     Casinos issue “player cards” to track the wagering activity of their customers during their casino stay or visit. Player cards are common enough to be considered a standard, industry-wide feature. Customer data that individual casino properties acquire from player cards is proprietary to the casino property collecting the customer data or to the casino owners. Therefore, such data is typically not shared between or among competing casino operations.  
         [0009]     The absence of an industry wide, shared historical wagering data platform creates a “disconnect” when players with established waging histories at one casino seek to patronize a second casino where they have no wagering history. In these instances, the second casino is ill prepared to quickly or conveniently provide such customers with comps at levels they may be accustomed to. This “walled garden” data structure that limits customer&#39;s freedom of choice by curtailing efficient, automated transfer of wagering profile related casino privileges or entitlements.  
         [0010]     Numerous business models have proven that consumers tend to retaliate when their access or freedom is arbitrarily limited. As a result, the use of containment tactics in businesses can have the affect of lowering overall customer satisfaction levels and potentially limiting a markets true potential.  
         [0011]     One prior arrangement provides a multi-player tracking system that tracks a player&#39;s wagering levels at any one of a several gaming venues. This system, however, requires a “new” management information system be installed over the top of the current information system at each casino property. It is commonly known that whenever a new system installation requires an existing business system to be changed or replaced, particularly where large established companies are concerned, a significant amount of time and expense is generally required to affect such change. Furthermore, such requirements can also prohibit adoption altogether.  
         [0012]     Promotional activities such as providing “comps” motivate and stimulate consumer purchases. People are attracted by the opportunity to win or receive things perceived as being free. In fact, use of the “free” is so effective in motivating consumer purchase decisions that use of the word is regulated in certain industries to prevent abuse.  
       SUMMARY OF THE INVENTION  
       [0013]     In accordance with the principles of the invention “comps,” generally perceived by customers as free bonuses or rewards, are more effectively utilized as an important and compelling promotional tool for casinos. Accordingly, access to a universally accessible player wagering profile database would open up the market for casinos to use comps to more readily promote growth and profitability using a more efficient, automated system.  
         [0014]     We have determined that what would greatly benefit the casino industry and casino consumers to provide an arrangement that (i) collects consumer related wagering profile data and stores it to a non casino specific wagering database, (ii) aggregates such data, in a cumulative manner, into a database that can is accessible by participating casino members, and (iii) provides a casino travel related website where casinos, having electronic access to said player wagering data, can offer individually tailored, incentive comp packages to attract new customer business and motivate existing customers to increase their frequency of visits.  
         [0015]     A method in accordance with the invention includes: providing a database of customer wagering profiles; receiving a request from a potential customer for a destination casino hotel reservation; obtaining wagering profile data for the potential customer from the database; providing a modified or enhanced request by attaching the wagering profile data for the potential customer to the enhanced request; utilizing the enhanced request to generate one or more promotional incentive offers; and responding to the request with at least one reservation option including said one or more promotional incentive offers.  
         [0016]     A marketing method for customer specific promotions in accordance with the invention includes: receiving from a requesting customer an electronic request for promotional offers via a website connected to a global computer network or via a device located in a casino and coupled to a communications network; attaching wagering profile data from the requesting customer to the electronic request to provide an enhanced request; sending the enhanced request to one or more casino properties to produce promotional incentive offers corresponding with the request, the incentive offers being proportional to the requesting customer&#39;s wagering profile; and responding to the request with one or more promotional offers. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0017]     The invention will be better understood from a reading of the following detailed description in conjunction with the drawing figures in which like designators are used to identify like elements, and in which:  
         [0018]      FIG. 1  illustrates a system in accordance with the principles of the invention;  
         [0019]      FIG. 2  illustrates steps in registering a user of the system and method of the invention;  
         [0020]      FIG. 3  illustrates steps in providing incentive offers in accordance with the principles of the invention;  
         [0021]      FIG. 4  illustrates principal components of the customer specific marketing system and method including a participating casino property, data interfaces, and customer wagering profile database and casino destination travel website;  
         [0022]      FIG. 5  illustrates the participating casino property operations components and wagering data access, transferred and sharing arrangements in a preferred system structure;  
         [0023]      FIG. 6  illustrates a method by which consumers enroll as registered users of the system and establish system accounts;  
         [0024]      FIG. 7  illustrates the method by which the registered users wagering data is captured from participating casinos and the processing of such data within the systems database operations;  
         [0025]      FIG. 8  illustrates how registered users operate the system website and the related system interaction with participating casino properties to develop promotional comp package offers for such registered users; and  
         [0026]      FIG. 9  illustrating a sample system generated casino air/room travel package options and the structure and process by which registered users select such travel package options. 
     
    
     DETAILED DESCRIPTION  
       [0027]     When a casino&#39;s historical data modeling tools or reservation records, or similar tools or data sources, project or indicate a probability there will be unsold inventory levels, it is highly desirable for casino operators to utilize such potentially unsold inventory as a promotional tool to attract gaming business (since corresponding incremental expense requirements for such promotional use are generally small and if the inventory is not used it is lost anyway).  
         [0028]     The present invention provides a highly effective yield management tool for the casino resort industry to optimize the value of entertainment related assets by providing access to an industry-wide wagering profile database and features to use this data to design customer specific comp promotions to attract new customers and increase business from existing customers.  
         [0029]     In accordance with the principles of the invention a yield management strategy for casino operators provides (i) access to a potential customer while the potential customer is making casino resort destination travel purchase decisions, (ii) the ability to make and modify promotional comp package incentive offers to a potential customer in real time, and (iii) access to accurate data on each potential customer&#39;s historical waging data to tailor promotional offers on a per customer basis.  
         [0030]     A casino property participates in and uses a customer specific marketing program in accordance with the invention after entering into an agreement to be a participant. In accordance with the agreement the participating casino provides registered user waging data collected by the casino to a system database. Still further a participating casino agrees to promote enrollment in the system to its patrons.  
         [0031]     Any member of the general public may enroll to become a system user on-line via a system supported web site or at terminals or kiosks located in participating casinos. The terminals or kiosks are programmed to read system registered user account cards. Each prospective user of the system participates in a registration process. During the registration process, the prospective user enters appropriate identification information, gaming preferences and wagering profile data. The information entered by the prospective user is checked for integrity and entered into a database along with a user account code or number which is provided back to the user at conclusion of the registration process.  
         [0032]     When a registered user utilizing a web site enters casino destination travel plans, the system identifies participating casino properties at geographically relevant locations. By way of example, a registered user may indicate that he or she would like to stay in a casino-resort located on the “strip” in Las Vegas or in Atlantic City or elsewhere. The system will associate the desired travel plans along with the user&#39;s waging history profile data from the system database. The system transmits a requestor&#39;s identity information, travel request travel dates or visit specifications and wagering profile data to geographically relevant participating casino resorts.  
         [0033]     The participating casino resorts utilizing one or more software programs to draw on inventory management data generate promotional offers in response to the potential customer&#39;s that are proportional to the user&#39;s wagering profile and the currently available inventory to said registered users. The promotional offer or offers are returned to the user who has initiated the request.  
         [0034]     By providing wagering profile data and working in cooperation with participating casinos, the system of the present invention offers relevant and valuable promotional incentive packages to its registered user customer base. As the casino industry matures, casinos continue to develop a wider array of premium entertainment services that can be provided as incentives for casino brands to attract and retain customers. Such premium entertainment, however, comes at a significant expense to casino properties and therefore must be carefully managed. As a safeguard, in order to offer such premium entertainment as a comp to secure potential customer business, casino properties need assurance that such promotional investments are proportional with the waging level of recipient customers. With access to the system&#39;s database, casinos are provided with efficient, automated access to important customer specific wagering profile data on an industry-wide level so they can focus their decision processes inventory management variables to maximize their yield in real time. And the more history wagering profile data available to a casino the easier it is for such casinos to offer incrementally greater promotional incentives to attract and retain customers. As a result, the system provides a compelling reward based program to motivate players to become registered users and actively participate (with the system) to build the broadest, most comprehensive player wagering history they can.  
         [0035]     Turning now to  FIG. 1 , participating resort-casino properties  13  each include a computer system  12  that has access to a database  14 . Database  14  includes wagering data for past and current casino players. The records stored in database  14  are associated with players such that wagering data may be selectively retrieved or updated for each player registered in database  14 . Casino computer system  12  also has access to promotional comp information for various comps that resort-casino property  13  has determined are available for players. Examples of such comp information is inventory information for entertainment, meals and rooms. The comp information is stored in database  14  also. It should be noted that although one database  14  is shown, in fact, there may me multiple databases that are utilized to store the comp information and player wagering data. In addition, each participating resort-casino property  13  may separately determine the correlation between various wagering determinative factors recorded in database  14  and comps that may be offered to a prospective guest.  
         [0036]     System  11  includes a server  25  and its related databases  24 . Server  25  responds to reservation requests received from prospective resort-casino property guests that are received via an electronic network  3  which, in the illustrative embodiment of the invention, is the Internet. A prospective guest may utilize an Internet accessing device  5  which may, for example, be a computer terminal, pda, internet accessing cell phone or other such device to access server  25  via Internet  3 . Alternatively, the prospective guest may access another web site which in turn is linked to server  25 . In any event, a prospective guest is initially asked via terminal  5  whether he or she is a registered user of system  11 .  
         [0037]      FIG. 2  illustrates the registration process for a new user of system  11 . The system of the invention maintains a database of registered customers at step  201 . When a system user or prospective guest logs onto system  11 , the prospective guest is linked directly or indirectly to server  25 . At step  203  it is determined whether or not the prospective guest is already a registered member. If the guest is a registered member, the guest logs in to the system by entering identification information. System  11  verifies the log in of the guest and the guest may then enter travel destination information is asked to provide his/her registration identification if he/she is a registered user.  
         [0038]     If prospective guest is not a registered user, the prospective guest is asked to register to use the system at step  203 . A unique identifier and As part of the registration process, the prospective user is requested to and must provide identification information, and player club information for all casinos where the prospective user has registered to provide a user profile. System  11  associates a unique account identifier and a customer database record in customer database for each registered potential customer at step  205 . The user provides personal identification and contact information at step  207  and the user creates user name and password at step  209 . The user provides personal identification and contact information, and selects a user name and password which are stored in customer database record at step  211 . The user provides at least one of personal gaming preference and wagering profile information at step  213 . System  11  stores personal gaming preference and wagering profile information stored in customer database record at step  215 . The user provides account numbers for active player card accounts at step  217  and the player account numbers stored in customer database record at step  219   
         [0039]     The user then may log on to use system  11 . As with a previously registered user, system  11  verifies the log in. If the log in is not verified, the user is returned to a log in page. If the log is verified server  25  accepts reservation information from the prospective guest.  
         [0040]     Server  25  provides prompts to the user for obtaining appropriate reservation information from the user, including geographic destination information and desired dates and other typical reservation information. Once server  25  receives the reservation request information from the user, server  25  obtains wagering data for the guest from database  24  and appends the wagering data to the reservation request.  
         [0041]     Server  25  identifies participating casino properties that meet the geographic preference of the user. Server  25  transmits the reservation request and wagering data to the participating casino properties that have been identified.  
         [0042]     As shown in  FIG. 3 , System  11  receives a request from said potential customer for a destination reservation at step  301 . System  11  obtains wagering profile data from first database at step  303 . System  11  utilizes wagering profile data to generate one or more promotional incentive offers from one or more casino properties for potential customer at step  305 . System  11  responds to the request with at least one promotional incentive offer. Each request includes travel plans of potential customer, plans include one or more dates of departure and dates of return and trip destination location at step  307 . System  11  responds to said request with reservation options for air transportation at step  309 . After receiving an acceptance by potential customer of at least one potential incentive offers at step  311 , the system provides acceptance to the casino property. During this process system  11  determines whether the potential customer is a new customer to the casino property at step  313 . If so, the casino property prepares a player card account for said potential customer at step  315 . The casino property makes the player card available to customer for pick-up upon arrival at said casino property at step  317 . System  11  updates wagering profile data with wagering profile information collected during each time period that a customer is a registered as being at casino property at step  321 . The casino may provide each of said incentive promotional offers on a “play to qualify” basis at step  323 . In such case, the casino will determine the promotional incentives at the end of the time period that a customer is registered as being at casino property at step  325 . The amount or level of promotional incentive offered to a customer may be based on the amounts wagered by said customer during a stay at a casino property at step  327   
         [0043]     As illustrated in  FIG. 4 , participating casino properties  13  identified as being within the destination receive the reservation request and the wagering information for the requesting user. The casino computer system  12  accesses its data base at step  303  to identify its available inventory for the prospective guests choice of date. Casino computer system  12  may also access its players club database if the prospective user is a member of its players club.  
         [0044]     Casino computer system  12  utilizing the reservation request information, the wagering data appended to the reservation request and its inventory, to generates one or more promotional incentives to induce the prospective guest to utilize its facilities. The promotional incentive is appended to a response to the prospective guest that is returned to server  25 .  
         [0045]     Server  25  assembles responses from all participating casinos that respond to the reservation request and makes the responses available to the prospective user for access via the Internet.  
         [0046]     Turning now to  FIG. 5   a  resort-casino property  13  is shown schematically. It will be appreciated that although only one resort-casino property is shown in  FIG. 5 , the principles of the invention are applicable to a group of related resort-casino properties or groups of related casino properties or a group of unrelated casino properties. Casino-resort property  13  includes a computer system  12  that either includes or has access to a database  14 . Casino-resort property  13  includes a players club and issues players club cards  15 .  
         [0047]     One or more kiosks  17 , shown in greater detail in  FIG. 7  are co-located at resort-casino  13 . Each kiosk  17  includes a card reader  18  for reading of system cards  27 , a keypad input device  19  and a graphical display  20 . Kiosks  17  are shown illustratively. The particular appearance and structure of each kiosk forms no part of the present invention. It is intended that the use of the term “kiosk” herein is intended to include any substantially freestanding input/output terminal that would be placed in a public area for use by the general public.  
         [0048]     As illustrated in  FIG. 5 a  casino property operation becomes a participating casino property  13 , by entering into an agreement  32  agreeing to provide server  25  access to casino database  14  for providing wagering data collected from registered users during the period such users are actively involved in gaming at the participating casino property  13 . Upon executing the agreement  32  participating casino properties  13  provide appropriate data formatting information and necessary code/content instruction  34  from the participating casino property management information system administrator. A participating casino property  13  shares wagering history data that guests registered with system  11  generate while playing at the participating casino property  13  and transfers such data from casino database  14  to system  11 .  
         [0049]      FIG. 6 , illustrates two ways a customer may enroll as a registered users of system  11 . A customer can enrollment to become registered users at either a kiosk  17  or via the Internet utilizing an internet accessing device  5 . The customer receives appropriate instructions to register via a registration screen at step  601 . At the new user registration screen, consumers input user identification and contact information (i.e., mailing address, phone numbers, etc.) and information related to gaming preferences and wagering related profile data  43 . The new user is prompted to enter account username and password information. Thereafter the system  11  creates a unique account number  44  for the new registered user to manage and maintain a corresponding registered user customer data file  26  within the system  11  database  24 . System  11  transfers the corresponding registered user customer data file  26  to an account card processing center  45  to process a registered user system account card  27 .  
         [0050]     Subsequent to completing registration, a registered user is provided a system account card  27 . System account card  27  includes memory, which in the illustrative embodiment is a readable/writeable magnetic data strip thereon compatible with kiosk  17 . The magnetic strip allows the registered user to view account profile data  26  or have the account data  26  on the system account card  27  updated at a system kiosk  17 .  
         [0051]     A registered user can access system  11  to make casino destination air/room travel plans. When a registered users checks in at a casino-hotel, the hotel check in and check out times serve as automatic start time and stop time indicators eliminating the need to use the user card  27  at a system kiosk  17  to mark data collection start and stop times.  
         [0052]     Turning back to  FIG. 4 , a registered user inserts an account card  27  into kiosk  17  reader  18  at the beginning of a participating casino gaming session. The registered user also inserts an account card  27  into a reader  18  at the conclusion of a session  16  to indicate to the system  21  the period of time the registered user was actively engaged in gaming activity at the participating casino property  13 . Upon collecting the start and stop time information  21 , the system  11  sends an electronic request  22  to casino database  14  for wagering data for the registered user for the corresponding gaming period. System  11  converts the captured and transferred wagering data into an appropriate database format for storage in the system database  24 . Every system registered user has a customer data file  26  which stores registered users customer identification information and compiled and aggregated wagering history data from system  11 .  
         [0053]     As shown in  FIGS. 8 and 9 , the system&#39;s marketing operation platform  23  includes a website  28  where registered users can book casino destination air/room reservations and/or request and receive casino comp offers corresponding with their walk in casino visit plans.  
         [0054]     In accordance with the principles of the invention a terminal or kiosk  17  located within participating casino properties  13  is used to register a start  52  and stop  53  time relative to a registered users gaming activity at a participating casino during a corresponding gaming. At the onset of a gaming session a registered user swipes their system card  27  in the system kiosk  17  reader  18  and keys in the appropriate instruction at the keypad  19  to log the start time of the registered users gaming session  52 . At the conclusion of the a gaming session the registered user swipes their system card  27  in the system kiosk  17  reader  18  and keys in the appropriate instruction at the keypad  19  to log the stop time of the registered users gaming session  53 .  
         [0055]     After a registered user logs their gaming session ending time, an electronic data file defining account number for the registered user, the wagering session time and corresponding participating casino that was wagered at is sent to the system database operations server  25 . A copy of this data along with a request for the corresponding wagering profile data for the gaming session period is sent  55  from the system database server  25  to the casino database  14 . Upon receipt of the electronic request  55  from the system  11  the casino database  14  transmits  56  back to the system server  25  with the corresponding registered users wagering data for the gaming session period. Upon receipt of request wagering profile data  56  the system server  25  sends the casino  13  data to the next sequential data processing operations  57 . The systems casino account identification and sorting operations  58  analyze the historical wagering data files  22  to determine the originating registered casino account for the participating casino  13 . Once the originating registered casino account is determined, the corresponding casino property  13  electronic data format  34  information is retrieved and wagering data  22  is converted to the system&#39;s  11  format  59 . Thereafter, the system  11  updates the corresponding registered user&#39;s data file  26  with the historical wagering data  60  and then updates the central system database operations  61 .  
         [0056]     As shown in  FIGS. 8 and 9  registered users may request casino destination travel airline ticket and hotel reservation pricing  61  and receive as part of the request  61 , promotional comp incentives offers  68  at the system  28  website.  
         [0057]     When a registered system user enters the system  11  website  28  to search for casino destination travel and entertainment package options, they log on as a registered user  62  and enter their desired travel specification (date and city of departure, return date, number of passengers, etc.)  63 . Via the system  11  server  25  the system database operations  24  then combines the registered users travel specifications  63  with the registered users customer data file  26  wagering history data and electronically transmits this customer and travel plan information to participating casino properties  13 ,  65  at relevant locations (in geographical proximity to destination of registered users travel plan specifications  63 ). With the registered user/system  11  supplied travel specifications  63  and corresponding registered user wagering history data  26  the participating casino resorts  13  utilize their own internal, inventory/yield management software programs to prepare promotional offers tailored to the travel specifications  63  and customized for the registered users wagering history data  26  and transmit  66  to the system  11  server  25  and database operations  24 . The promotional offers  67  are then sent  68  to the website  28  for the registered user to review.  
         [0058]     As shown in  FIG. 9 a  system  71  that defines the format of system responses to requests  61  for casino air/room travel package pricing and options. Casino resort air/room travel packages  72  delivered by the system  11  include a casino resort package  73 , made up of a hotel room options  74  and comp package options  75 , and airline ticket options  76 . Airline ticket options  76  are made up of a multiple of individual airline ticket options  77  from one or more carriers. Similarly, casino resort package options are made up of a multiple of individual hotel room choices  79  from various casino properties  13  and multiple of individual comp package options  80 . Any airline ticket option  77  can be freely interchanged with any hotel room/comp package set  78 . Hotel room  79  and comp package components  80 , however, of a casino resort package option  78  can not be removed from their package and interchanged with other casino resort  74  hotel room  79  or comp package  80  components.  
         [0059]     At the conclusion of registered user&#39;s gaming sessions or trips to participating casinos, electronic requests for corresponding wagering data is sent to the casino. Upon collection, the wagering data is added to the users&#39; customer data file in the system database. Related wagering data downloads build users waging history profiles, enabling registered users to receive potentially greater promotional value from participating casinos when requesting air/room travel reservations or promotion offers through the system. Using the waging profile database the system provides individual tailored promotional comp offers to registered users requesting casino destination air/room travel reservation options or promotional offers for walk in casino visits at the system website or at system authorized kiosks.  
         [0060]     The invention has been described in terms of several embodiments. It is not intended that the invention be limited in scope to the specific embodiments shown and described. It will be appreciated by those skilled in the art that various changes and modifications may be made without departing from the spirit of the invention.