Abstract
    This article detailed records of a dual-beam bridge crane trolley part of the calculation and design process, mainly by car or from the institutions, agencies and the car running small frame consists of three parts, as well as a number of security devices, is an important component of the crane.
  （1）Lifting bodies from the motor, transmission, Reel, brakes, pulleys and hook group composed.

（2）agencies from the motor, transmission, As a result of these parts of the structure and composition of different ways, there can be many forms.

（3）The car running small frame consists ，Use of mechanical analysis, the small frame structure and materials.

Calculations based on technical parameters, in the operation of institutions of good work, noise, long life, low-cost principle, a more appropriate choice of the motor, reducer and other assistive devices
Keywords： double-beam bridge crane、 trolley, lifting bodies、car run institutions.