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Bridge Launch Linkage Assembly



OBJECTIVE: Develop smart linkage mechanism to unfold 63-foot-long scissor type Bridge with mechanical advantages other than traditional cable-pulley and built-in hydraulic linear cylinder launchers. The expected concept and layout of the design can be adapted to rapid launch and retrieval movement, light in weight and easy interconnection with electrical or hydraulic servo systems for programmable motion profile and control algorithm. 

DESCRIPTION: This SBIR topic will deliver a novelty design and technology by applying a linkage mechanism to unfold Army Armored Vehicle Launched Bridge (AVLB). Army AVLB is based on a tank chassis, but instead of the tank's gun turret, it is equipped with a bridge launcher integrated into the chassis and mounted on top. When emplaced, the bridge is capable of supporting tracked and wheeled vehicles with a military load bearing capacity up to Class 85. The bridge can be retrieved from either end. During deployments, bridge emplacement can be accomplished in 2 minutes, and retrieval can be accomplished in 10 minutes under armor protection. There are two types of launcher mechanisms, built-in hydraulic cylinder and cable-pulley, for this Army scissoring-type Assault Bridge. Because of this in-bridge hydraulic cylinder, AVLB’s weight is heavy. It also requires regular maintenance to hydraulic lines, while cable-pulley design offers limited motion profile, less stability and lower speed in launch and retrieval. Proposed mechanism should utilize its mechanical advantage and optimization of location of joint of linkage for Military Load Class (MLC) 85 on the bridge. In general, weight reduction to the current in-bridge set of hydraulic cylinder and cable-pulley is approx. 25% (threshold), 50% (objective). The general idea for linkages in that type of application is achievable. However, to integrate linkage assembly with the bridge set in such restricted area could be a challenge, as well as extreme loads at linkage joints and irregular bar contour design. In addition, to interface with a rotary actuator and modular design is also the contest in this project, which could be a breakthrough of linkage application that requires advanced analysis and simulation before launching a prototype and integration with the full-size bridge. 

PHASE I: Demonstrate feasibility of algorithm using basic linkage theory to calculate loads at joints for this 30klb-weight bridge, acquire data set comprising either the design intent and a possible motion profile or a statistically robust number of concepts and, registry of measurement accuracy by comparing the results to analysis conducted. With help of software simulation, it is towards a modeling and algorithm to perform a design and load optimization based on the analysis and the data set. 

PHASE II: Design and build a scaled prototype with hydraulic or electric actuators to validate the concept and design. Delivered prototype must be suitable for testing and validation at an Army facility by technical personnel. Clear operational manuals required but not in military format. During this phase, the Army expects to work closely with the Contractor to clarify mission integration requirements appropriate for the initial prototype maturity. 

PHASE III: Final solution is a standardized module for the AVLB bridging system. A launch design works with the Bridge and Tank chassis to meet all the requirements of Army assault bridging. The Army can integrate the technology developed under this SBIR into an end item to answer assault bridge launch requirements. Industry could insert the technology developed under this SBIR in facilities utilizing the latest motion control technology. Further application may be realized for both hydraulic and electric actuators. 


1: DOD Directive 5000.40 - Reliability and Maintainability

2:  MIL-STD-785B - Reliability Program for Systems and Equipment, Development and Production

3:  MIL-STD-721C - Definitions of Terms for Reliability and Maintainability


Michael Z. Shen 

(586) 282-6999 

Bernard J. Sia 

(586) 282-6101 

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