Device for centering a sensor assembly in a bore

A device for centering a sensor assembly in a bore, the device comprising:

• a first support member and a second support member axially spaced apart along a longitudinal axis of the device;
• a plurality of arm assemblies connected between the first and second support members, each arm assembly comprising:
• a first arm pivotally connected to the first support member by a first pivot joint having a first pivot axis,
• a second arm pivotally connected to the second support member by a second pivot joint having a second pivot axis,
• a third arm connected between the first and second arms, the third arm pivotally connected to the first arm by a third pivot joint having a third pivot axis, and the third arm pivotally connected to the second arm by a fourth pivot joint having a fourth pivot axis,
• wherein the third pivot axis is located on a first side of a plane coincident with the longitudinal axis of the device, and the fourth pivot axis is located on an opposite second side of the plane, and
• a third support member positioned axially between the first and second support members, the third arm pivotally connected to the third support member by a fifth pivot joint having a fifth pivot axis coincident with the plane,
• the third arm extending through the plane coincident with the longitudinal axis of the device, so that in use each arm assembly contacts opposite sides of the bore to centralise the sensor assembly in the bore.