Multiple switch control system

Claim 1

A control system for controlling accessory equipment in a motor vehicle wherein control switches are located in the hub of a steering wheel of said motor vehicle remote from a control circuit network, said control system including: (a) a source of power and a return; (b) a first voltage divider including at least a first resistance and a common junction between said source of power and said return; (c) a second voltage divider including at least a plurality of resistors in series connection between said source of power and said return; (d) a plurality of substantially identical parallel circuits connected sequentially between said source of power and said return, each circuit of said plurality of circuits including a first input, a second input, a comparator, a logic gate, a switch and a load; (e) said first input of each said circuit connected to said common junction for applying a first voltage to said comparator of each said circuit; (f) said second input of each said circuit connected to said second voltage divider for applying a second voltage to said comparator of each circuit such that the value of said second voltage applied to the respective comparator is different from the value of that voltage applied to adjacent comparators as a function of the sequential position of the circuit along said second voltage divider; (g) each said circuit of said plurality of circuits, except the first circuit of said plurality of circuits positioned along said second voltage divider further including one inverter, said inverter connected between the output of said comparator and one of the inputs of said logic gate of the parallel circuit in the higher adjacent position along said second voltage divider; (h) a plurality of resistance elements equal in number to the number of circuits in said plurality of circuits and connected in parallel connection to each other and each resistance element of said plurality of resistance elements connected in series connection between said common junction and said return for changing the value of said first voltage when one or the other of said resistance elements is electrically inserted between said common junction and said return; (i) said switch of each said circuit having a normally open condition and a closed condition, driven to a closed condition in response to an output from a logic gate of the circuit of which each component is a part, said switch for electrically closing an electric circuit to at least one acessory of said accessory equipment of said motor vehicle when said switch is in said closed condition; and, (j) a plurality of switch means equal in number to the number of resistance elements in said plurality of resistance elements and connected in parallel with each other and each switch of said plurality of switch means connected in series with at least one of said resistance elements of said plurality of resistance elements and each said switch of said plurality of switch means connected to said return for electrically inserting a different resistance element each into said first voltage divider for driving one circuit of said plurality of substantially identical, parallel circuits for controlling at least one accessory of said accessory equipment.