Liquid dispensing pump

In a dispensing pump having a reciprocable plunger head mounted on a pump body member for the dispensing of product from a container upon plunger reciprocation, stop means on said head, a control member rotatably mounted on said body member and having an axial opening through which said stop means extends during plunger reciprocation, at least one upstanding locking finger being deflectable transversely to the axis of reciprocation of said plunger into the path of reciprocation of said stop means, the improvement wherein said locking finger is secured to said control member and has a downwardly facing stop shoulder located toward the lower end thereof, said stop means on said plunger head comprising an upwardly facing stop shoulder, opposing cam means on said body member in constant engagement respectively with opposing surfaces of said locking finger for positively deflecting said finger and said downwardly facing stop shoulder thereon transversely into as well as out of the path of said stop means, respectively, in response to relative rotary movement of said members, whereby said plunger head may be locked in a depressed position relative to said body member, and any tendency to inadvertently unlock said plunger head is prevented while any interference between said head and said finger during plunger reciprocation is avoided.