Escalator Comb Plate Impact Device Spring Reliability Upgrade

Detection of comb plate movement in either the horizontal or vertical direction is required by Code. The comb impact device is designed to shut the motor off and activate the brake in the event that comb plate movement is detected. This is vital for the safety of the riding public. 

An improved design comb plate impact device is available for existing Montgomery/KONE HR Series escalators that utilize a conical spring washer (Belleville Washers) to provide resistance/force within the mechanism.

The improved impact device utilizes a “compression spring” providing for an improved maintenance process and reliability through less frequent lubrication, repair and simpler adjustment requirements.

This improved design is recommended for all HR Series comb plate applications; however, it can be especially effective in humid/corrosive environments where the Belleville washers require frequent lubrication to protect against corrosion.  

In addition, the new design simplifies and allows for mechanism adjustments to provide horizontal tripping loads equal to 400 lbf without exceeding the vertical trip load limit of 150 lbf as defined by the current ASME A17.1, Rule Comb-Step Impact Devices.  This “kit” bolts on to the existing comb plate carrier.


  • Less frequent lubrication; Protects against corrosion
  • Simpler adjustment requirements
  • Meets ASME A17.1, Code, Rule Comb-Step Impact Devices