Safety push rod assemblies

Claim 1

Safety push rod assemblies for a container filling machine provided with a circular bonnet rotatable continuously on a vertical axis beneath a filling tank, each of said assemblies comprising a vertical sleeve adapted to extend through the marginal portion of the bonnet and be rigidly mounted therein, a tubular upper rod slidably mounted in said sleeve and extending above it, a container rest mounted on top of the sleeve, a lower rod slidably mounted in said upper rod and extending down below said sleeve, a lower rod being provided with a transverse passage therethrough inside the upper rod, a detent ball in each end of said passage, the lower rod also having an axial bore extending from its upper end down to said passage, a center ball in the lower end of said bore resting on both detent balls, a stop in the upper end of said bore, a coil spring compressed between said stop and center ball for urging said detent balls into engagement with the encircling upper rod, the upper rod having depressions in its inner surface receiving the portions of the detent balls projecting from said passage to thereby normally hold the push rod assembly in extended positions with said container rest spaced a predetermined distance from the lower end of the lower rod, a cam follower roller carried by the lower end of the lower rod for raising both rods to elevate a container on said rest into filling position, the upper rod being movable downwardly around the lower rod to collapse said assembly if the load on said rest creates a downward force that overcomes the resistance of the detent balls to being forced toward each other against the resistance of said coil spring, and a pull down roller carried by the lower end of the lower rod for pulling that rod downwardly in the upper rod until said coil spring forces the detent balls out into said depressions again.