GB670872A - Improvements in pressure cookers - Google Patents

Abstract

670,872. Pressure cookers. NATIONAL PRESSURE COOKER CO. March 17, 1947 [June 20, 1946], No. 7368/47. Class 123(i) The cover 12 of a domestic pressure cooker is locked to the body portion 11 by the engagement of inwardly and outwardly projecting lugs 31, 30 on the two parts respectively, and fluid tightness is secured by a rubber &c. sealing ring 25 which is housed in a groove 26 in the skirt 27 of the cover and projects therefrom to contact a bevelled surface 24 on the peripheral flange 21 of the body portion. As shown, the lugs 30 are provided on their underside with an initial locking surface or step 32 and a fully-closed locking step 33, with a rounded shoulder 34 therebetween, the arrangement being such that, upon applying the cover to the body and rotating same in a clockwise direction as seen from above, the lugs 31 will first ride over the steps 32, to bring the parts into the position shown in Fig. 4, and then over the steps 33 to initiate a sealing pressure of the ring 25 upon the surface 24, Fig. 3, this sealing being augmented later by the internal pressure within the cooker acting upon the upper exposed area 28 of the said ring. The cover is removed by rotation in the opposite direction, the lugs 31 riding over the initial locking steps 32 in an intermediate position, Fig. 4, to permit the cover to lift slightly and release any internal pressure, thus preventing the cover from being blown off inadvertently. Rotation of the cover in the wrong direction and beyond the fully-closed position is prevented by a pin 36 which projects from the body flange 21 upwardly into the path of the cover lugs 31. In a modification the steps 32, 33 are provided on the upper face of the lugs 31.