Patent ID: 8051731

Claim:
A spring reaction force converting apparatus comprising: a first member and a second member arranged to be parallel with and opposed to each other and to be capable of being moved toward or apart from each other; a spring member that has a coil spring member positioned between the first and second members and is arranged for being extended and compressed in a direction parallel to the first and second members, the coil spring member having a central portion in which a core member configured to be able to extend and contract is interposed; a link mechanism configured to hold the spring member between the first and second members such that the spring member is free to expand and contract, the link mechanism being arranged to be in connection to the first and second members, wherein the link mechanism includes a first set of end portions connected to both end portions of the core member of the spring member, a second set of end portions connected to the first member at two positions separated apart from each other by a distance greater than a length of the spring member, a third set of end portions connected to the second member at two positions separated apart from each other by a distance greater than a length of the spring member, and four levers for connecting both end portions of the spring member to the first member and the second member, and wherein the link mechanism is configured to move the first and second members toward or apart from each other while maintaining the first and second members to be in parallel with each other; a stopper member configured to maintain the spring member held by the link mechanism in a state where the spring member is compressed by a predetermined amount in an initial state; and an arrangement in which a reaction force exhibited by the spring member compressed by an operation force applied to the first and second members is transmitted to the first member and the second member, respectively, via the link mechanism, wherein as the first and second members move toward each other, the reaction force progressively decreases, and wherein as the first and second members move apart from each other, the reaction force progressively increases such that the operation force progressively decreases until a period of termination of the application of the operation force with respect to an initial period thereof.