Patent ID: 8689661

Claim:
A lever arm assembly comprising a segmented lever arm able to curl and having a proximal end and a distal end, the lever arm carrying a drive connection at the proximal end for turning a driven member, the drive connection having a drive axis that is substantially perpendicular to the plane in which the lever arm curls, the lever arm being capable of being brought from a curled first condition to an uncurled, straightened second condition wherein in the curled first condition the lever arm is curled around the drive axis and the distal end is closer to the drive axis than it is in the second condition to provide a lever for turning the driven member, and when the lever arm is in the uncurled second condition the proximal end and the distal end are spaced further apart, to provide a longer lever for turning the driven member, wherein the lever arm comprises a plurality of blocks linked and articulated to one another by a flexible chain connector, wherein the blocks are shaped to engage with one another in said first condition and in said second condition, wherein each block is provided with a pair of substantially parallel oppositely facing walls that engage with corresponding walls of a respectively adjacent block in said second condition, and a pair of oppositely inclined sloping walls that engage with corresponding sloping walls of the respectively adjacent blocks in said first condition, and wherein each linked pair of blocks having a wall of one block of the pair that opposes a wall of another block of the pair when the lever arm is in said second condition in use, limiting deflection of the lever arm and thereby rigidifying the straightened extended lever arm for use as a lever for turning the driven member.