Device for automatically controlling the closure of the decompression valve of an internal combustion engine

Claim 1

In a device for automatically ceasing the decompression of an internal combustion engine and comprising a decompression valve for the engine, which valve has a closing position and an opening position, a return spring combined with the valve for urging the valve to said closing position, manual actuating means movable between a closed valve position and an open valve position for shifting the valve to said opening position thereof in opposition to the effect of the spring, connecting means connecting the actuating means to the valve; the improvement comprising delay means for delaying the return of the valve to said closing position of the valve by the effect of said return spring when said actuating means is moved to said closed valve position, said delay means comprising a control member connected to the connecting means and movable by the connecting means substantially in a plane between a first position in which the valve is in the said opening position and a second position in which the valve is in said closing position, said spring being operative to bias the control member toward said second position, a finger member mounted on the control member to move transversely of said plane, a shaft for rotation by said engine when cranking the engine and defining a helical groove leading to an outer extremity of the shaft, the shaft being so positioned relative to the control member that the control member, in moving in a direction from said first position to said second position under the action of said spring, is operative to move the finger member toward and into lateral engagement with said helical groove so that the movement of the control member to said second position to close the valve is blocked by said shaft and delayed until the finger member has travelled longitudinally along the shaft in the helical groove as the shaft rotates upon cranking the engine and has reached the outer extremity of the shaft, whereupon the finger member suddenly ceases to be blocked by said shaft and is free to move laterally beyond the shaft and allows the control member to move to said second position and suddenly close the valve.