Abstract: A stress failure resistant container cap for a threaded neck container in the nature of a carboy, such as large acid carboys, wherein the containers are usually large and heavy and closure caps therefor are also extremely heavy in structure. Carboys, for example, are sufficiently large that users sometimes over-tighten the cap using a wrench or similar tool. This can result in cap failures due to stress cracking due to the high torque applied to the cap. The high torque applied to the cap, and its coaction with the threads of the neck, when high or excessive torques are applied, tend to apply a strain in the corner juncture between the cap top and neck thereof. This can, and frequently has, resulted in cracking of the cap material. The strain is applied by a tendency to apply a bending force to the cap at the juncture corner.

Abstract: A dual function cap member for a necked container having a material dispensing opening and a closure seal membrane securely attached thereover. The cap member is double sided and reversable. One side of the cap member has means coactable with the container neck to form a container closure cap. The reverse side of the cap has closure seal membrane piercing means operative, upon removal and reversal of the cap member from the closure cap position, to pierce and spread open the central area of the membrane. A peripheral portion of the so-pierced and opened membrane remains securely attached to the container neck about the dispensing opening for continued attachment of the membrane material to the container neck. The cap member, subsequent to membrane piercing, and possible dispensing of material from the container, is again operative, upon reversal, to serve as a selectively removable container closure cap to close and seal the dispensing opening.

Abstract: A container-closure assembly comprising a container having a body portion and an elongated externally threaded neck at one end having a discharge opening normally closed by a membrane, a locking collar at the juncture of the neck and body portion projecting radially beyond the circumferential trace of the threads of the neck of the container and a closure adapted to be mounted over the discharge end of the container comprising a cap portion of generally cup-like form having internal threads and a piercing element projecting from the inside face of the top of the container and a skirt of a larger diameter than the cap connected to the lower edge of the cap by fracturable bridge means and locking means at the lower terminal edge of the skirt cooperating with the locking collar to prevent removal of the closure from the container.