DZL Series steel telescopic device is the summary of a variety of large displacement expansion features, based on the situation for heavy-duty high-density traffic has successfully developed a new type of large displacement telescopic device. DZL Series steel telescopic device is based on the principle of anti-fatigue dynamics and design with a single support beam of elastic support system as well as joint action by the shear spring series of displacement control system. With a carrying capacity, superior fatigue resistance, uniformity and other characteristics of displacement control. DZL Series steel telescopic device ability to adapt to a three-dimensional displacement of the bridge, with driving comfort, long life, compact structure, easy maintenance and many other advantages. For all kinds of roads and bridges, it is the preferred structure suspension bridge, cable-stayed bridge and continuous concrete bridge.