Abstract: Disclosed is a closure means for a pressure vessel, said pressure vessel comprising a body portion and a lid portion, the closure means comprising: securing means attached to the lid portion for releasably securing the body and lid portions together to form a subtantially gastight enclosure, the securing means permitting a limited degree of movement between the body and lid portions from a sealing position to a venting position when the pressure within the vessel exceeds the external pressure by a predetermined amount thereby permitting venting of excess pressure, the closure means comprising biasing means acting to bias movement of the body and lid portions from the venting position to the sealing position after venting of excess pressure, and pressure vessels comprising said closure means.

Abstract: In a piezo-electric manually-operated spark generating device the actuating mechanism comprises an actuating lever pivoted on the body of the device which accommodates the piezo-electric crystal assembly. It is arranged that in response to pivotal movement of the lever a cam rotates through a small angle between a fixed abutment and a relatively fixed head or pressure pad of the crystal assembly to exert high pressure on the crystal assembly for the generation of sparks. The cam is formed with precision by blanking or stamping from sheet metal so that it does not need to be subsequently machined as in the case of prior cam construction which would increase the cost of the cam. The stamping out or blanking of the cam from sheet metal also enables a roll pin to be formed integrally with the cam instead of being a separate member which is received by a hole in the cam.