depressed, the process being repeated until detachment is complete. Care should be taken that the winged nuts remain flush with the rim throughout.
If a single lever only be available the removal of a cover requires more strength and more dexterity. The left hand should
Fig. 5 |
Fig. 6 |
press the cover outwardly as much as possible, the point of the lever should be insinuated between the beaded edge and the rim, but not beneath the air-chamber, and the position shown in fig. 7 should be attained, by pulling the cover forward with
Fig. 7 |
Fig. 8 |
the left hand and depressing the lever with the right. Avoid the position shown in fig. 8. Slide the lever, which should be moistened, between the rim and the beaded edge, and as the latter is progressively unhooked press downwards on the cover, as in fig. 9, to prevent any slipping back. The case or other-