Piezoelectric actuator

A piezoelectric actuator (28) comprises a stack body (30) including a plurality of piezoelectric elements (32), each element having a positive and negative electrode pair (40a, 40b) which are electrically isolated from one another by the piezoelectric element (32), positive contact means (44) in electrical connection with the positive internal electrodes (40a) of the pairs and negative contact means (44) in electrical connection with the negative internal electrodes (40a) of the pairs. First and second charge distribution means (42, 48) are connectable with a power supply, in use, to permit voltage to be applied across the stack body (30). Each of the first and second charge distribution means (42) includes a distribution member (48) coupled electrically to the respective one of the positive or negative contact means (44) by means of a plurality of flexible conductor members (50). The flexible conductor members ensure that any contraction and/or expansion of the contact means (44) as the stack body (30) contracts/expands does not result in any disconnection to the internal electrodes which would otherwise affect actuator performance.