Abstract: A gripper mechanism for moving an object having a surface cavity, the gripper mechanism comprising an actuation end moveable in an axial direction and a rotary body. A first mechanism is configured such that movement of the actuation end in an axial direction rotates the rotary body. A gripper is moveable between an engaged position and a disengaged position. In the engaged position the gripper is capable of engaging an object and in the disengaged position the gripper is capable of being received into and removed from a cavity of an object. The gripper is connected to the rotary body by a second mechanism. The second mechanism is configured such that rotary motion of the body moves the gripper between the engaged position and the disengaged position.

Abstract: A gripper mechanism for moving an object having a surface cavity, the gripper mechanism comprising an actuation end moveable in an axial direction and a rotary body. A first mechanism is configured such that movement of the actuation end in an axial direction rotates the rotary body. A gripper is moveable between an engaged position and a disengaged position. In the engaged position the gripper is capable of engaging an object and in the disengaged position the gripper is capable of being received into and removed from a cavity of an object. The gripper is connected to the rotary body by a second mechanism. The second mechanism is configured such that rotary motion of the body moves the gripper between the engaged position and the disengaged position.

Abstract: Sodium sulphur cells are commonly connected in parallel. It is a problem with such arrangements that if one cell sustains a short circuit failure, the parallel connected cells discharge through it. In an embodiment disclosed, a switch series connected to a cell or series of cells, goes open circuit should current in excess of a predetermined value and consequently associated with the failure of a cell, flow through the switch. The switch comprises a conducting rod separated into two portions and placed within a beta alumina tube containing sodium: the level of the sodium determines whether an electrical circuit is completed between the portions rendering the switch "on". Sodium, contained within an outer conducting tube, also surrounds the inner beta alumina tube, there being an electrical connection from the outer tube, via a resistor, to one portion of the rod.