The present invention relates to wheeled vehicles and in particular to toy racing cars competing on a track and whose steering and drive functions are controlled by steering consuls attached to a controlling box which in turn is attached to the track by a pair of wires and all of which is powered by a mains adaptor which delivers a safe low voltage supply.
The inventive significance of this design over present state of the art inventions is inherent in the digital method of transmitting the control signals from these "consuls" to provide error free control of multiple vehicles and at low cost.
Moreover the small scale of the vehicles provided for in the present invention allows for the use of smaller scale track than would otherwise be necessary and so further making the game more commercially feasible.
US Pat. No. 3,841,556 Oct 15 1974 describes a system using a roadbed capable of receiving superimposed A.C. or D.C. signals from an external controller, which can be used in combination with a wheeled vehicle of the type disclosed in U.S. Pat. No. 3,590,526 July 6 1971. The problems associated with these particular designs are due to the fact that they are essentially analog based. I.e. multiple analog signals characterising the user control mechanisms outputs, are superimposed upon each other to produce a composite analog signal which is again superimposed onto the supply voltage to the track. These signals interfere with one another to some degree and thereby distort the linearity of the control signals which are fed to steering and drive motors on board the vehicles and further the number of vehicles which can be operated simultaneously is restricted due to the necessarily large separations of the bandwidths allotted to each channel.
The design described in the present application overcomes these shortcomings by virtue of using only one signal. The change in that signal denotes a bit pattern similar to that used in serial digital communications generally, and is encoded at the transmitter and decoded at the receiver to prevent distortion or interference along the way. The added advantage is that any number of vehicles can operate simultaneously without fear of distorting the control signals of an adjacent vehicle.
It is known to use a continuous slotted track of parallel dipoles to propel wheeled vehicles, which derive their power, by brushes riding on the dipole and control of the vehicle's speed is by use of hand operated throttle/s electrically connected to the track dipoles.
European Patent No. 553 555 describes an improvement in these "slot" cars whereby rigid "shoes" are used in place of "brushes" for more continuous electrical contact between car and track dipole:
European Patent No. 307659 describes a slotted track game as above but with the added advantage of permitting the vehicles to jump between adjacent tracks for the purpose of passing out other vehicles and thereby making the game more interesting.
U. S. patent No.3, 590,526 and U. S. patent No.3, 841,556 used together provide for a system of steer able vehicles on a flat roadbed, which provides power and analog controlling signals to the vehicles. The object being to imitate real racing cars with full steering / drive control has obvious appeal over its predecessors.
The object of the present invention is to provide cost effective error free control of toy racing cars operating on a flat surface containing a dipole known as a track.
A most important feature of the invention is the method used to deliver the control signals from the user control consuls to the steering / drive motors on board the vehicles. A single encoded serial digital data stream produced by a modulator / controller circuit contains all the information to control the multiple of vehicles which may be driven simultaneously thereby eliminating the problems of competing signal interference inherent in previous analog patent designs. And further the digital data recovered by the vehicles is verified within the decoders before their outputs are updated and applied to the steering / drive motors thus guarding against contaminated or lost signals as frequently happens when the vehicles are in motion due to grease or other on the track surface causing intermittent disconnection between the vehicles and the track dipole.
According to the invention, there is provided:
The digital design of the present invention allows for more cost effective, error free control of even smaller scale vehicles and track than presently Patented designs are capable of achieving. Moreover, the number of vehicles and thereby competitors which can simultaneously be accommodated is not limited as in previous designs due to their inherent bandwidth restrictions. Finally as is the case in most digital systems as opposed to analog designs, reliability is far superior in the former and indeed component tolerances which might otherwise affect analog circuitry performance is much less of a problem in digital designs generally.
The invention relates to wheeled vehicles deriving interference free controlling signals and power at all locations across a smooth partially conductive track surface containing a dipole by virtue of contact shoes or brushes which connect with the dipole.
In prior art document U.S. 3,841,556A in conjunction with document US 3,590,526 there is disclosed an invention relating to wheeled vehicles on a roadbed similar to the present invention but whose controlling signals are subject to distortion due to the analog method of transmitting these signals as opposed to the superior digital method outlined below.
In particular the invention relates to a toy racing car game whereby readily available steering consul/s are adapted for the driving control of miniature competing racing vehicle/s on a track composed of several sections so as to imitate real life Formula 1 or Rally car racing.
The invention is described with reference to drawings Fig 1 through Fig. 7.
Fig 1 illustrates a track composed of just two joined sections, 8 & 9 which can be further added to, to complete a continuous track. Lateral dipole 6 & 7 connects to the appropriate track surface segments 4 & 5 to polarise the conductive surface.
Insulation layer 10 separates the dipole being wider than the maximum shoe contact area to avoid a possible short circuit. Spring contact Shoes 2 & 3 are shown to be in contact with the dipole and it can be appreciated that alternation of the polarity is catered for due to internal rectifier diodes producing the required Direct Current (DC) supply.
Track sections are physically and electrically coupled by conductors 7 & 6, which are in turn connected to the external controller 12 by a pair of wires 11. Multiple
Steering/drive consuls 14 connect to controller 12 and further mains adaptor 13, which delivers a safe low voltage supply, powers everything.
Fig 2 illustrates a possible steering mechanism for use on such a vehicle. Servomotor 15 containing pinion wheel 16 moves a rack 17 with rod end 18 to turn wheels 19.
Fig 3 illustrates a drive mechanism usually found on miniature electric cars. Motor 26 with stator 24 and rotor 25 containing pinion wheel 23 geared for increased torque by gear wheel 22 which turns axial 21 and thus drive wheels 20.
Fig 6 and its compliment Fig7 illustrate a practical digital design example of the circuitry necessary to implement the present invention. Potentiometer/s 14 provide digital data concerning their position to encoders 27 whose outputs are sequenced through a switch 28 controlled by oscillator/counter 29 to FSK modulator 30 which produces two tones representing a "1" and "0" logic respectively which are superimposed upon the low voltage power supply lines 11 attached to the track dipole by amplifier/adder 32. Switch 31 is forward / reverse actuator.
Fig 7 details the vehicle circuitry necessary to compliment Fig 6. There are shoes 2&3, which pick up power and signals from the track. The DC (Direct Current) is derived by rectifiers 33 and is fed to regulator 34 for voltage stabilisation. The signals are isolated from the power lines by capacitor/s and fed to limiter / shaper amplifier 35.
The sinusoidal tones are fed to FSK demodulator 36 and resulting encoded digital serial data fed to decoder 37 and parallel digital data is converted to an analog signal via D/A converter 38. Comparator 39 compares voltage from servo potentiometer and produces resulting servo drive voltage for steering via pinion wheel 16.
The speed control voltage is derived by D/A converter 38A and direction is obtained by switching relay 40 whose coil 41 is energised by digital line from decoder. Motor 26 is geared to produce required torque to turn the wheels.