Introduction to Park Brake (Handbrake) Setting:
CLAVIS tension setting equipment has been employed worldwide  in automotive manufacturing plants for over 15 years. Primarily used for belt tension setting, CLAVIS equipment has a reputation for innovative design, quality and reliability, backed by an outstanding field technical support team.

Optimum parking brake cable adjustment is achieved when the brake pads or brake shoes are at the limit of the safe distance away from the disc or drum. This corresponds to a caliper lever movement typically of 2mm of travel away from the lever rest position.

In this system measurement tools are temporarily locked onto the caliper when the vehicle enters the adjustment station. The tools measure the movement of the caliper lever to an accuracy better than 0.02mm. When a measurement tool is initially located the tool references the measurement system to the position of the caliper lever. All future measurements are made with respect to this reference so that the effects from caliper dimensional variability are eliminated.

The measurement tools (one of the left side caliper and one on the right side caliper) communicate with a control cabinet using UHF radio telemetry links.

The control cabinet interfaces with an electric power tool (Standard interfaces exist for Stanley, Atlas Copco and George Renault tools). After the measurement tools have been located it is only necessary for the operator to place the power tool on the adjustment nut and then hold down the trigger of the power tool. The cycle is complete when the tool stops. If a fault occurs during the cycle the power tool will also stop and alert the operator by audible and visual warnings.

When the operator places the electric power tool on the cable adjustment nut and commences run-down, the cycle begins.




                                             
1. The cable is 'scragged' to remove the elastic deformation from the system. Scragging may be terminated by either;

a) The caliper lever reaching a pre-determined travel position
b) The torque on the adjustment nut reaching a set level
c) Or by lever force measurement in situations where lever travel is limited by the measurement tool.

If scragging is terminated by lever position, both the right and left side levers must have made the scragg position before the cycle terminates. This ensures that both sides are adequately scragged even if the cable equaliser is offset.

2. At the end of the scragg cycle, the power tool automatically reverses so that the adjustment nut is wound back. The caliper levers therefore return to their initial rest positions. Both levers must be back at rest before the final adjustment procedure begins.

3. The final adjustment part of the operation advances the caliper levers to the target displacement value, which has been determined by the manufacturer of the caliper.

During the whole cycle intelligent monitoring of the position of the caliper levers occurs to detect such process faults as;

Failure to locate the cable termination in either the caliper lever or cable equaliser

Unequal cable lengths either due to a manufacturing fault, or failure to locate the cable outer sheath correctly.