Other types of play systems involve the use of blocks for building structures. These blocks often include structure for providing an interlocking relationship between abutting blocks.

In this way, elaborate structures can be created by users with creative minds. However, such structures are generally built by hand.

Tests have indicated that there is a desirability, and even a need, for play systems in which vehicles are remotely operated to perform functions other than to move aimlessly along a floor or along the ground. For example, tests have indicated that there is a desirability, and even a need, for a play system in which the remotely controlled vehicles can transport elements such as blocks to construct creative structures. There is also a desirability, and even a need for play systems in which a plurality of vehicles can be remotely controlled by switches in hand-held pads to compete against one another in performing a first task or to co-operate in performing a second task such as building a miniature community through the transport of miniature blocks. Such a desirability, or even a need, has existed for a long period of time, probably decades, without a satisfactory resolution.

BRIEF DESCRIPTION OF THE INVENTION This invention provides a play system for use by people of all ages with youthful minds. It provides for a simultaneous control by each player of an individual one of a plurality of remotely controlled vehicles. This control is provided by the operation by each such player of switches in a hand-held unit or

pad, the operation of each switch in such hand-held unit providing a control of a different function in the individual one of the remotely controlled vehicles.

Each of the remotely controlled vehicles in the system of this invention can be operated in a competitive relationship with others of the remotely controlled vehicles or in a co- operative relationship with others of the remotely controlled vehicles. The vehicles can be constructed to pick up and transport elements such as blocks or marbles and to deposit such elements at displaced positions.

When manually closed in one embodiment of the invention, switches in pads control the selection of toy vehicles and the operation of motors for moving the vehicles forwardly, rearwardly to the left and to the right and moving upwardly and downwardly (and rightwardly and leftwardly) a receptacle for holding transportable elements (e. g. marbles).

When sequentially and cyclically interrogated by a central station, each pad sends through wires to the station signals indicating the switch closures in such pad. Such station produces first binary signals addressing the vehicle selected by such pad and second binary signals identifying the motor control operations in such vehicle. Thereafter the switches identifying in such pad the motor control operations in such selected vehicle can be closed without closing the switches identifying such vehicle.

The first and second signals for each vehicle are transmitted by wireless to all of the vehicles at a common carrier frequency modulated by the first and second binary signals. The vehicle identified by the transmitted address demodulates the modulating signals and operates its motors in accordance with such demodulation. When the station fails to receive signals from a pad for a particular period of time, the vehicle selected by such pad becomes available for selection by another pad and such pad can select that vehicle or another vehicle.

A cable may couple two (2) central stations (one as a master and the other as a slave) to increase the number of pads controlling by the vehicles. Stationary accessories (e. g. elevator) connected by wires to the central station become

operative when selected by the pads.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Figure 1 is a schematic diagram, primarily in block form, of a system constituting one embodiment of the invention; Figure 2 is a schematic diagram, primarily in block form, of the different features in a pad included in the system shown in Figure 1; Figure 3 is a schematic diagram, primarily in block form, of the different features included in a central station included in the system shown in Figure 1; and Figure 4 is a schematic diagram, primarily in block form, of the different features in a vehicle included in the system shown in Figure 1.

In one embodiment of the invention, a system generally indicated at 10 in Figure 1 is provided for controlling the selection and operation of a plurality of toy vehicles.

Illustrative examples of toy vehicles constitute a dump truck generally indicated at 12, a fork lift generally indicated at 14, a skip loader generally indicated at 16 and another form of skip loader generally indicated at 17. The toy vehicles such as the dump truck 12, the fork lift 14 and the skip loaders 16 and 17 are simplified versions of commercial units performing functions similar to those performed by the toy vehicles 12,14, 16 and 17. For example, the dump truck 12 may include a working or transport member such as a pivotable bin or container 18; the fork lift 14 may include a working or transport member such as a pivotable platform 20; the skip loader 16 may include a working or transport member such as a pivotable bin or container 22 disposed at the front end of the skip loader; and the skip loader 17 may include a working or transport member such as a pivotable bin or container 23 disposed at the rear end of the skip loader. The working or transport members such as the pivotable bin or container 18, the pivotable platform 20 and the pivotable bins or containers 22 and 23 are constructed to carry storable and/or transportable elements such as blocks 24 or marbles 26 shown schematically in Figure 1.

Each of the dump truck 12, the fork lift 14 and the skip

loaders 16 and 17 may include a plurality of motors. For example, the dump truck 12 may include a pair of reversible motors 28 and 30 (Figure 4) operable to move the dump truck forwardly, rearwardly, to the right and to the left. The motor 28 controls the movement of the front and rear left wheels and the motor 30 controls the movement of the front and rear wheels.

When the motors 28 and 30 are simultaneously operated in one direction, the dump truck 12 moves forwardly. The vehicle 12 moves rearwardly when the motors 28 and 30 are moved in the opposite direction. The vehicle 12 turns toward the right when the motor 30 is operated without simultaneous operation of the motor 28. The vehicle 12 turns toward the right when the motor 28 is operated without a simultaneous operation of the motor 30.

The vehicle 12 spins to the right when the motor 30 operates to move the vehicle forwardly at the same time that the motor 28 operates to move the vehicle rearwardly. The vehicle 12 spins to the left when the motors 28 30 are operated in directions opposite to the operations of the motors in spinning the vehicle to the right.

Another reversible motor 32 in the dump truck 12 operates in one direction to pivot the bin 18 upwardly and in the other direction to pivot the bin downwardly. An additional motor 33 may operate in one direction to turn the bin 18 to the left and in the other direction to turn the bin to the right.

The construction of the motors 28,30,32 and 33 and the disposition of the motors in the dump truck to operate the dump truck are considered to be well known in the art. The fork lift 14 and the skip loaders 16 and 17 may include motors corresponding to those described above for the dump truck 12.

The system 10 may also include stationary plants or accessories. For example, the system 10 may include a pumping station generally indicated at 34 (Figure 1) for pumping elements such as the marbles 26 through a conduit 36. The system may also include a conveyor generally indicated at 38 for moving the elements such as the marbles 26 upwardly on a ramp 40. When the marbles reach the top of the ramp 40, the elements such as the marbles 26 may fall into the bin 18 in the dump truck 12 or into the bin 22 in the skip loader 16. For the purposes of this application, the construction of the pumping

station 34 and the conveyor 38 may be considered to be within the purview of a person of ordinary skill in the art.

The system 10 may also include a plurality of hand-held pads generally indicated at 42a, 42b, 42c and 42d (Figure 1).

Each of the pads 42a, 42b, 42c and 42d may have a substantially identical construction. Each of the pads may include a plurality of actuatable buttons. For example, each of the pads may include a 4-way button 44 in the shape of a cross. Each of the different segments in the button 44 is connected to an individual one of a plurality of switches 46,48,50 and 52 in Figure 2.

When the button 44 is depressed at the segment at the top of the button, the switch 46 is closed to obtain the operation of the motor 28 (Figure 4) in moving the selected one of the vehicle 12 forwardly. Similarly, when the segment at the bottom of the button 44 is depressed, the switch 48 is closed to obtain the operation of the motor 28 (Figure 4) in moving the vehicle 12 rearwardly. The selective depression of the right and left segments of the button 44 cause the motor 30 to operate in turning the selected vehicle toward the right and the left.

It will be appreciated that pairs of segments of the button 44 may be simultaneously depressed. For example, the top and left portions of the button 44 may be simultaneously depressed to obtain a simultaneous movement of the vehicle 12 forwardly and to the left. However, a simultaneous actuation of the top and bottom segments of the button 44 will not have any effect since they represent contradictory commands. This is also true of a simultaneous depression of the left and right segments of the button 44.

Each of the pads 42a, 44b, 42c and 42d may include a button 56 (Figure 1) which is connected to a switch 57 (Figure 2).

Successive depressions of the button 56 on one of the pads within a particular period of time cause different ones of the stationary accessories or plants such as the pumping station 34 and the conveyor 38 to be energized. For example, a first depression of the button 56 in one of the pads 42a, 42b, 42c and 42d may cause the pumping station 34 to be energized and a second depression of the button 56 within the particular period of time in such pad may cause the conveyor 38 to be energized.

When other stationary accessories are included in the system 10, each may be individually energized by depressing the button 56 a selective number of times within the particular period of time. When the button 56 is depressed twice within the particular period of time, the energizing of the pumping station 34 is released and the conveyor 38 is energized. This energizing of a selective one of the stationary accessories occurs at the end of the particular period of time.

A button 58 is provided in each of the pads 42a, 42b, 42c and 42d to select one of the vehicles 12,14,16 and 17. The individual one of the vehicles 12,14,16 and 17 selected at any instant by each of the pads 42a, 42b, 42c and 42d is dependent upon the number of times that the button is depressed in that pad within a particular period of time. For example, one (1) depression of the button 58 may cause the dump truck 12 to be selected and two (2) sequential selections of the button 58 within the particular period of time may cause the fork lift 14 to be selected.

Every time that the button 58 is actuated or depressed within the particular period of time, a switch 59 (in Figure 2) is closed. The particular period of time for depressing the button 58 may have the same duration as, or a different time than, the particular period of time for depressing the button 56. An adder is included in the pad 12 to count the number of depressions of the button 58 within the particular period of time. This count is converted into a plurality of binary signals indicating the count. The count is provided at the end of the particular period of time.

Buttons 60a and 60b are also included on each of the pads 42a, 42b, 42c and 42d. When depressed, the buttons 60a and 60b respectively close switches 62a and 62b in Figure 2. The closure of the switch 62a is instrumental in producing an operation of the motor 32 in a direction to lift the bin 18 in the dump truck 12 when the dump truck has been selected by the proper number of depressions of the button 58. In like manner, when the dump truck 12 has been selected by the proper number of depressions of the switch 58, the closure of the switch 62b causes the selective one of the bin 18 in the dump truck 12, the platform 20 in the fork lift 14 and the bin 22 in the skip

loader 16 and the bin 23 in the skip loader 17 to move downwardly as a result of the operation of the motor 32 in the reverse direction.

It will be appreciated that other controls may be included in each of the pads 42a, 42b, 42c and 42d. For example, buttons 61a and 61b may be included in each of the pads 42a, 42b, 42c and 42d to pivot the bin 18 to the right or left when the vehicle 12 has been selected. Such movements facilitate the ability of the bin 18 to scoop elements such as the blocks 24 and the marbles 26 upwardly from the floor or ground or from any other position and to subsequently deposit such elements on the floor or ground or any other position.

Switches 63a and 63b (Figure 2) are respectively provided in the pad 42a in association with the buttons 61a and 61b and are closed by the respective actuation of the buttons 61a and 61b to move the bin or the platform in the selected one of the vehicle 12 to the left or right when the vehicle has been selected. It will be appreciated that different combinations of buttons may be actuated simultaneously to produce different combinations of motions. For example, a bin in a selected one of the vehicles may be moved at the same time that the selected one of the vehicles is moved.

A central station generally indicated at 64 in Figure 1 processes the signals from the individual ones of the pads 42a, 42b, 42c and 42d and sends the processed signals to the vehicles 12,14,16 and 17 when the button 58 on an individual one of the pads has been depressed to indicate that the information from the individual ones of the pads is to be sent to the vehicles.

The transmission may be on a wireless basis from an antenna 68 (Figure 1) in the central station to antennas 69 on the vehicles.

The transmission may be in packets of signals. This transmission causes the selected ones of the vehicles 12,14,16 and 17 to perform individual ones of the functions directed by the depression of the different buttons on the individual ones of the pads. When the commands from the individual ones of the pads 42a, 42b, 42c and 42d are to pass to the stationary accessories 34 and 38 as a result of the depression of the buttons 56 on the individual ones of the pads, the central

station processes the commands and sends signals through cables 70 to the selected ones of the stationary accessories.

Figure 2 shows the construction of the pad 42a in additional detail. It will be appreciated that each of the pads 42b, 42c and 42d may be constructed in a substantially identical manner to that shown in Figure 2. As shown in Figure 2, the pad 42a includes the switches 46,48,50 and 52 and the switches 57, 59,62a, 62b, 63a and 63b. Buses 74 are shown as directing indications from the switches 46,48,50,52,57,59,62a, 62b, 63a and 63b to a microcontroller generally indicated at 76 in Figure 2. Buses 78 are shown for directing signals from the microcontroller 76 to the switches.

The microcontroller 76 is shown as including a read only memory (ROM) 80 and a random access memory (RAM) 82. Such a microcontroller may be considered to be standard in the computing industry. However, the programming in the microcontroller and the information stored in the read only memory 80 and the random access memory 82 are individual to this invention.

The read only memory 80 stores permanent information and the random access memory stores volatile (or impermanent) information. For example, the read only memory 80 may store the sequence in which the different switches in the pad 42a provide indications of whether or not they have been closed. The random access memory 82 may receive this sequence from the read only memory 80 and may store indications of whether or not the switches in the particular sequence have been closed for each individual one of the pads 42a, 42b, 42c and 42d.

The pad 42a in Figure 2 receives the interrogating signals from the central station 64 through a line 84. These interrogating signals are not synchronized by clock signals on a line 86. Each of the interrogating signals intended for the pad 42a may be identified by an address individual to such pad.

When the pad 42a receives such interrogating signals, it sends to the central station 64 through lines 88 a sequence of signals indicating the status of the successive ones of the switches 46, 48,50 and 52 and the switches 57,59,62a, 62b, 63a and 63b.

These signals are synchronized by the clock signals on the line 86. It will be appreciated that the status of each of the

switches 57 and 59 probably is the first to be provided in the sequence since these signals indicate the selection of the stationary accessories 34 and 38 and the selection of the vehicles 12,14,16 and 17., As previously indicated, the pad 42a selects one of the vehicles 12,14,16 and 17 in accordance with the number of closings of the switch 59. As the user of the pad 42a provides successive actuations or depressions of the button 58, signals are introduced to a shift register 90 through a line 92 to indicate which one of the vehicles 12,14,16 and 17 would be selected if there were no further depressions of the button.

Each one of the depressions of the button 58 causes the indication to be shifted to the right in the shift register 90.

Such an indication is provided on an individual one of a plurality of light emitting diodes (LED) generally indicated at 93. The shifting of the indication in the shift register 90 may be synchronized with a clock signal on a line 95. Thus, the illuminated one of the light emitting diodes 93 at each instant indicates at that instant the individual one of the vehicles 12, 14,16 and 17 that the pad 42a has selected at such instant.

The central station 64 is shown in additional detail in Figure 3. It includes a microcontroller generally indicated at 94 having a read only memory (ROM) 96 and a random access memory (RAM) 98. As with the memories in the microcontroller 76 in the pad 42a, the read only memory 96 stores permanent information and the random access memory 98 stores volatile (or impermanent) information. For example, the read only memory 96 sequentially selects successive ones of the pads 42a, 42b, 42c and 42d to be interrogated on a cyclic basis. The read only memory 96 also stores a plurality of addresses each individual to a different one of the vehicles 12,14,16 and 17.

Since the read only memory 96 knows which one of the pads 42a, 42b, 42c and 42d is being interrogated at each instant, it knows the individual one of the pads responding at that instant to such interrogation. The read only memory 96 can provide this information to the microcontroller 94 when the microcontroller provides for the transmittal of information to the vehicles 12, 14,16 and 17. Alternatively, the microcontroller 76 in the pad 42a can provide an address indicating the pad 42a when the

microcontroller sends the binary signals relating to the status of the switches 46,48,50 and 52 and the switches 57,59,62a, 62b, 63a and 63b to the central station 64.

As an example of the information stored in the random access memory 98 in Figure 3, the memory stores information relating to each pairing between an individual one of the pads 42a, 42b, 42c and 42d and a selective one of the vehicles 12, 14,16 and 17 in Figure 1 and between each individual one of such pads and a selective one of the stationary accessories 34 and 38. The random access memory 98 also stores the status of the operation of the switches 46,48,50 and 52 for each pad and the operation of the switches 57,59,62a, 62b, 63a and 63b for each pad.

When the central station 64 receives from the pad 42a the signals indicating the closure (or the lack of closure) of the switches 46,48,50 and 52 and the switches 57,59,62a, 62b, 63a and 63b, the central station retrieves from the read only memory 96 the address of the individual one of the vehicles indicated by the closures of the switch 59 in the pad. The central station may also retrieve the address of the pad 42a from the read only memory 96.

The central station 64 then formulates in binary form a composite address identifying the pad 42a and the selected one of the vehicles 12,14,16 and 17 and stores this composite address in the random access memory 98. The central station 64 then provides a packet or sequence of signals in binary form including the composite address and including the status of the opening and closing of each of the switches in the pad 42a.

This packet or sequence indicates in binary form the status of the closure each of the switches 46,48,50 and 52 and the switches 57,59,62a, 62b, 63a and 63b.

Each packet of information including the composite addresses and the switch closure information for the pad 42a is introduced through a line 102 in Figure 3 to a radio frequency transmitter 104 in the central station 64. The radio frequency transmitter 104 is enabled by a signal passing through a line 106 from the microcontroller 94. This enabling signal is produced by the microcontroller 94 when the microcontroller confirms that it has received signals from the pad 42a as a

result of the interrogating signals from the central station 64.

When the radio frequency transmitter 104 receives the enabling signal on the line 106 and the address and data signals on the line 102, the antenna 68 (also shown in Figure 1) transmits signals to all of the vehicles 12,14,16 and 17.

However, only the individual one of the vehicles 12,14,16 and 17 with the address indicated in the packet of signals from the central station 64 will respond to such packet of signals.

The microcontroller 94 stores in the random access memory 98 the individual ones of the vehicles such as the vehicles 12, 14,16 and 17 being energized at each instant by the individual ones of the pads 42a, 42b, 42c and 42d. Because of this, the central station 64 is able to prevent the interrogated one of the pads 42a, 42b, 42c and 42d from selecting one of the energized vehicles. Thus, for example, if the vehicle 14 is being energized by one of the pads 42a, 42b, 42c and 42d at a particular instant, a first depression of the button 58 in the pad being interrogated at that instant will cause the vehicle 12 to be initially selected and a second depression of the button by such pad will cause the vehicle 14 to be skipped and the vehicle 16 to be selected.

Furthermore, in the example above where the pad 42a has previously selected the vehicle 14, the microcomputer 94 in the central station 64 will cause the vehicle 14 to be released when the pad 42a selects any of the vehicles 12,16 and 17. When the vehicle 14 becomes released, it becomes available immediately thereafter to be selected by any one of the pads 42a, 42b, 42c and 42d. The release of the vehicle 14 by the pad 42a and the coupling between the pad 42a and a selected one of the vehicles 12,14,16 and 17 are recorded in the random access memory 98 in the microcontroller 94.

The vehicles 12,14,16 and 17 are battery powered. As a result, the energy in the batteries in the vehicles 12,14,16 and 17 tends to become depleted as the batteries provide the energy for operating the vehicles. The batteries in the vehicles 12 and 14 are respectively indicated at 108 and 110 in Figure 3. The batteries 108 and 110 are chargeable by the central station 64 because the central station may receive AC power from a wall socket. The batteries are charged only for a

particular period of time. This particular period of time is preset in the read only memory 96. When each battery is being charged for the particular period of time, a light 109 in a circuit with the battery becomes illuminated. The charging current to each of the batteries 108 and 110 may be limited by a resistor 111. The light 109 becomes extinguished when the battery has been charged.

Each central station 64 may have the capabilities of servicing only a limited number of pads. For example, each central station 64 may have the capabilities of servicing only the four (4) pads 42a, 42b, 42c and 42d. It may sometimes happen that the users of the system may wish to be able to service more than four (4) pads. Under such circumstances, the microcontroller 94 in the central station 64 and a microcontroller, generally indicated at 94a, in a second central station corresponding to the central station 64 may be connected by cables 114a and 114b to an adaptor generally indicated at 115.

One end of the cable 114b is constructed so as to be connected to a ground 117 in the adaptor 115. This ground operates upon the central station to which it is connected so that such central station is a slave to, or subservient to, the other central station. For example, the ground 117 in the adaptor 115 may be connected to the microcomputer 94a so that the central station including the microcomputer 94a is a slave to the central station 64. When this occurs, the microcontroller 94 in the central station 64 serves as the master for processing the information relating to the four (4) pads and the four (4) vehicles in its system and the four (4) pads and the four (4) vehicles in the other system.

The expanded system including the microcomputers 94 and 94a may be adapted so that the address and data signals generated in the microcomputer 94a may be transmitted by the antenna 68 in the central station 64 when the central station 64 serves as the master station. The operation of the central station 64a may be clocked by the signals extending through a line 118 from the central station 64 to the adaptor 115 and through a corresponding line from the other central station to the adaptor.

The vehicle 12 is shown in additional detail in Figure 4.

Substantially identical arrangements may be provided for the vehicles 14,16 and 17. The vehicle 12 includes the antenna 69 for receiving from the central station 64 signals with the address of the vehicle and also includes a receiver 121 for processing the received signals. The vehicle 12 also includes the motors 28,30,32 and 33. Each of the motors 28,30,32 and 33 receives signals from an individual one of transistor drivers 120 connected to a microcontroller generally indicated at 122.

The microcontroller 122 includes a read only memory (ROM) 124 and a random access memory (RAM) 126. As with the memories in the pad 42a and the central station 64, the read only memory 124 may store permanent information and the random access memory 126 may store volatile (or impermanent) information. For example, the read only memory 124 may store information indicating the sequence of the successive bits of information in each packet for controlling the operation of the motors 28,30, 32 and 33 in the vehicle 12. The random access memory 126 stores information indicating whether there is a binary 1 or a binary 0 at each successive bit in the packet.

The vehicle 12 includes a plurality of switches 128,130 and 132. These switches are generally pre-set at the factory to indicate a particular Arabian number such as the number"5".

However, the number can be modified by the user to indicate a different number if two central stations are connected together as discussed above and if both stations have vehicles identified by the numeral"5". The number can be modified by the user by changing the pattern of closure of the switches 128,130 and 132. The pattern of closure of the switches 128,130 and 132 controls the selection of an individual one of the vehicles such as the vehicles 12,14,16 and 17.

The pattern of closure of the switches 128,130 and 132 in one of the vehicles can be changed when there is only a single central station. For example, the pattern of closure of the switches 128,130 and 132 can be changed when there is only a single central station with a vehicle identified by the numeral "5"and when another user brings to the central station, from such other user's system, another vehicle identified by the numeral"5".

The vehicle 12 also includes a light such as a light emitting diode 130. This diode is illuminated when the vehicle 12 is selected by one of the pads 42a, 42b, 42c and 42d. In this way, the other users can see that the vehicle 12 has been selected by one of the pads 42a, 42b, 42c and 42d in case one of the users (other than the one who selected the vehicle 12) wishes to select such vehicle. It will be appreciated that each of the vehicles 12,14,16 and 17 may be generally different from the others so each vehicle may be able to perform functions different from the other vehicles.

This is another way for each user to identify the individual one of the vehicles that the user has selected.

As previously indicated, the user of one of the pads such as the pad 42a selects the vehicle 12 by successively depressing the button 58 a particular number of times within a particular time period. This causes the central station 64 to produce an address identifying the vehicle 12. When this occurs, the central station 64 stores information in its random access memory 98 that the pad 42a has selected the vehicle 12. Because of this, the user of the pad 42a does not thereafter have to depress the button 58 during the time that the pad 42a is directing commands through the station 64 to the vehicle 12. As long as the buttons on the pad 42a are depressed within a particular period of time to command the vehicle 12 to perform individual functions, the microprocessor 94 in the central station 64 will direct the address of the vehicle 12 to be retrieved from the read only memory 96 and to be included in the packet of the signals transmitted by the central station to the vehicle 12.

The read only memory 96 in the microprocessor 94 at the central station 64 stores information indicating a particular period of time in which the vehicle 12 has to be addressed by the pad 42a in order for the selective coupling between the pad and the vehicle to be maintained. The random access memory 98 in the microcontroller 94 stores the period of time from the last time that the pad 42a has issued a command through the central station 64 to the vehicle 12. When the period of time in the random access memory 98 equals the period of time in the read only memory 96, the microcontroller 94 will no longer

direct commands from the pad 42a to the vehicle 12 unless the user of the pad 42a again depresses the button 58 the correct number of times within the particular period of time to select the vehicle 12., The vehicle 12 also stores in the read only memory 124 indications of the particular period of time in which the vehicle 12 has to be addressed by the pad 42a in order for the selective coupling between the vehicle and the pad to be maintained. This period of time is the same as the period of time specified in the previous paragraph. The random access memory 126 in the microcontroller 122 stores the period of time from the last time that the pad 42a has issued a command to the vehicle 12.

As previously indicated, the button 58 in the pad 42a does not have to be actuated or depressed to issue the command after the pad 42a has initially issued the command by the appropriate number of depressions of the button. When the period of time stored in the random access memory 126 of the microcomputer 122 in the vehicle equals the period of time in the read only memory 124, the microcontroller 122 issues a command to extinguish the light emitting diode 130. This indicates to the different users of the system, including the user previously controlling the operation of the vehicle 121 that the vehicle is available to be selected by one of the users including the user previously directing the operation of the vehicle.

When one of the vehicles such as the vehicle 12 is being moved in the forward direction, the random access memory 126 records the period of time during which such forward movement of the vehicle 12 is continuously occurring. This period of time is continuously compared in the microcontroller 122 with a fixed period of time recorded in the read only memory 124. When the period of time recorded in the random access memory 126 becomes equal to the fixed period of time recorded in the read only memory 124, the microcontroller 122 provides a signal for increasing the speed of the movement of the vehicle 12 in the forward direction. Similar arrangements are provided for each of the vehicles 14,16 and 17. This increased speed may illustratively be twice that of the original speed.

The system and method described above have certain

important advantages. They provide for the operation of a plurality of vehicles by a plurality of users, either on a competitive or a co-operative basis. Furthermore, the vehicles can be operated on a flexible basis in that a vehicle can be initially selected for operation by one user and can then be selected for operation by another user after the one user has failed to operate the vehicle for a particular period of time.

The vehicles being operated at each instant are also visible by the illumination of the lights 130 on the vehicle. The apparatus and method of this invention are also advantageous in that the vehicles are operated by the central station 64 on a wireless basis without any physical or cable connection between the central station and the vehicles.

Furthermore, the central station 64 is able to communicate with the vehicles in the plurality through a single carrier frequency. The system and method of this invention are also advantageous in that the vehicles can selectively perform a number of different functions including movements forwardly and rearwardly and to the left and the right and including movements of a container or bin or platform on the vehicle upwardly and downwardly or to the left or the right. Different movements can also be provided simultaneously on a coordinated basis.

There are also other significant advantages in the system and method of this invention. Two or more systems can be combined to increase the number of pads 142 controlling the operation of the vehicles 12,14 16 and 17. In effect, this increases the number of users capable of operating the system.

This combination of systems can be provided so that one of the systems is a master and the other is a slave. This prevents any confusion from occurring in the operation of the system. The system is also able to recharge the batteries in the vehicles so that use of the vehicles can be resumed after the batteries have been charged.

The system and method of this invention are also advantageous in the provision of the pads and the provision of the button and switches in the pads. As will be appreciated, the pads are able to select vehicles and/or stationary accessories through the operation of a minimal number of buttons and to provide for the operation of a considerable number of

different functions in the vehicles with a minimal number of buttons. In co-operation with the central station, the pads are able to communicate the selection of vehicles to the central station without indicating to the station, other than on a time shared basis, the identities of the vehicles being selected.

After selecting a vehicle, each pad does not thereafter have to indicate the identity of the vehicle as long as the pad operates the vehicle through the central station within a particular period of time from the last operation of the vehicle by the pad through the central station.

Although this invention has been disclosed and illustrated with reference to particular embodiments, the principles involved are susceptible for use in numerous other embodiments which will be apparent to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims.