The drive hub, along with the chart drive, create the electrical mechanism that moves the chart paper when a chart recorder is actively measuring data. The chart drive is powered by a motor that typically moves at a constant speed. The speed and efficiency of the chart drive is a significant factor in providing a consistent data recording session.
The drive hub is the portion of the chart recorder that connects the motor of the chart drive to the inside of the device itself. The first portion of the hub includes a chain that provides the direct link between the internal side recording device (near the power source/battery) and the drive. The second portion of the hub is a simple clip or knob that secures the chains position to the center of the drive – this is the same location as the center of the chart paper.
Multiple issues can arise via the chart drive and the chart hub. Because these two parts are connected, an issue with one part could cause issue with the other. The chart drive contains gears that allow chart paper to move at an exact speed for data measurement. If these gears become old, wet, rusty, or altered in any form, the drive will not work properly. The drive itself will suffer from similar issues because it is the motor that is responsible for moving these gears.
Drive hub issues will cause ineffective drive functioning if the chain becomes dislodged or broken, or the knob becomes loose or broken. Problems with the chart drive require attention from a technician unless the user is prepared to disassemble their device and work on the motor/gear system themselves. However, the drive hub is user-fixable just as the arm is – kits are sold online to replace this part manually.