Linked progressive jackpot system

Abstract

A gaming machine 10 has a display 14 and a game controller arranged to control images of symbols displayed on the display 14. The game controller is arranged to play a game 16 in which at least one random event is caused to be displayed on the display 14. If a predefined winning event occurs, the machine 10 awards a prize to a player. When a trigger condition occurs in a base game of the game 16, a bonus game feature is awarded comprising a series of bonus games. If a particular special symbol outcome occurs during any of the bonus games, the particular special symbol outcome is collected towards a jackpot prize awarding event.

I claim:  
     
         1 . A gaming machine having a display means and a game control means arranged to control images of symbols displayed on the display means, the game control means being arranged to play a game in which at least one random event is caused to be displayed on the display means and, if a predefined winning event occurs, the machine awards a prize to a player, wherein, when a trigger condition occurs in a base game, a bonus game feature is awarded comprising a series of bonus games and, if a particular special symbol outcome occurs during any of the bonus games, the particular special symbol outcome is collected towards a jackpot prize awarding event.  
     
     
         2 . The gaming machine of  claim 1  in which, when the feature occurs, the control means pre-selects a set of special symbol outcomes depending on the magnitude of a bet made by the player.  
     
     
         3 . The gaming machine of  claim 1  in which the special symbol outcome follows automatically after occurrence of a special symbol.  
     
     
         4 . The gaming machine of  claim 1  in which the special symbol outcome occurs only when the special symbol is acted on by the player.  
     
     
         5 . The gaming machine of  claim 1  in which the bonus game feature comprises a free game sequence of a predetermined number of free games, the free games being awarded when a predetermined scatter symbol trigger combination occurs in the base game.  
     
     
         6 . The gaming machine of  claim 5  in which if, during the playing of the bonus game feature, the scatter symbol trigger combination re-occurs it results in a further bonus game feature.  
     
     
         7 . The gaming machine of  claim 1  in which the special symbol outcome is a bonus symbol, being one of a bonus credit prize, a bonus feature and a jackpot symbol contributing to the awarding of a jackpot.  
     
     
         8 . The gaming machine of  claim 7  in which, when a predetermined special symbol appears on any one of the reels and is displayed on the display means, that special symbol animates to reveal one of a bonus credit prize, a bonus feature and one of a plurality of jackpot symbols.  
     
     
         9 . The gaming machine of  claim 8  in which the jackpot symbols are a mini jackpot symbol, a minor jackpot symbol, a major jackpot symbol and a grand jackpot symbol.  
     
     
         10 . The gaming machine of  claim 1  in which the special symbol outcomes are arranged in sets, the special symbol outcomes being arranged in a predetermined order within the set.  
     
     
         11 . The gaming machine of  claim 10  in which groups of sets are associated with each bet.  
     
     
         12 . The gaming machine of  claim 10  in which, if the base game played triggers the bonus game feature, the control means randomly selects one of the sets from the group associated with the bet that was made on the base game prior to the occurrence of the trigger condition.  
     
     
         13 . The gaming machine of  claim 11  in which, in respect of each set, a special symbol outcome of a fixed, low-value prize is associated with any special symbol that occurs after a predetermined number of positions in the set of special symbol outcomes.  
     
     
         14 . The gaming machine of  claim 1  in which, if the player wishes to access a progressive jackpot feature of the bonus game feature, an additional wager has to be staked by the player.  
     
     
         15 . A system including a plurality of linked gaming machines as claimed in  claim 1 .  
     
     
         16 . The system of  claim 15  in which the base games of the gaming machines have certain aspects in common.  
     
     
         17 . The system of  claim 16  in which the base games differ thematically and/or mathematically from each other.  
     
     
         18 . A gaming machine having a display means and a game control means arranged to control images of symbols displayed on the display means, the game control means being arranged to play a game in which at least one random event is caused to be displayed on the display means and, if a predefined winning event occurs, the machine awards a prize, wherein, when a trigger condition occurs in a base game, a bonus game feature is awarded comprising a plurality of bonus games in which special symbols occur that result in special symbol outcomes and, when the feature occurs, the control means pre-selects a set of special symbol outcomes depending on the magnitude of a bet made by a player.  
     
     
         19 . The gaming machine of  claim 18  in which the special symbol outcome follows automatically after occurrence of a special symbol.  
     
     
         20 . The gaming machine of  claim 18  in which the special symbol outcome occurs only when the special symbol is acted on by the player.  
     
     
         21 . The gaming machine of  claim 18  in which the bonus game feature comprises a free game sequence of a predetermined number of free games, the free games being awarded when a predetermined scatter symbol trigger combination occurs in the base game.  
     
     
         22 . The gaming machine of  claim 21  in which if, during the playing of the bonus game feature, the scatter symbol trigger combination re-occurs it results in a further bonus game feature.  
     
     
         23 . The gaming machine of  claim 18  in which the special symbol outcome is a bonus symbol, being one of a bonus credit prize, a bonus feature and a jackpot symbol contributing to the awarding of a jackpot.  
     
     
         24 . The gaming machine of  claim 23  in which, when a predetermined special symbol appears on any one of the reels and is displayed on the display means, that special symbol animates to reveal one of a bonus credit prize, a bonus feature and one of a plurality of jackpot symbols.  
     
     
         25 . The gaming machine of  claim 24  in which the jackpot symbols are a mini jackpot symbol, a minor jackpot symbol, a major jackpot symbol and a grand jackpot symbol.  
     
     
         26 . The gaming machine of  claim 18  in which the special symbol outcomes are arranged in sets, the special symbol outcomes being arranged in a predetermined order within the set.  
     
     
         27 . The gaming machine of  claim 26  in which groups of sets are associated with each bet.  
     
     
         28 . The gaming machine of  claim 26  in which, if the base game played triggers the bonus game feature, the control means randomly selects one of the sets from the group associated with the bet that was made on the base game prior to the occurrence of the trigger condition.  
     
     
         29 . The gaming machine of  claim 26  in which, in respect of each set, a special symbol outcome of a fixed, low-value prize is associated with any special symbol that occurs after a predetermined number of positions in the set of special symbol outcomes.  
     
     
         30 . The gaming machine of  claim 18  in which, if the player wishes to access a progressive jackpot feature of the bonus game feature, an additional wager has to be staked by the player.  
     
     
         31 . A system including a plurality of linked gaming machines as claimed in any one of the preceding claims.  
     
     
         32 . The system of  claim 31  in which the base games of the gaming machines have certain aspects in common.  
     
     
         33 . The system of  claim 32  in which the base games differ thematically and/or mathematically from each other.