We present and analyze two arm exoskeletons based on a pantograph linkage that allow for the support of 89~N (20~pounds) at the user's hand. Using a pantograph linkage allows for a constant force to be created at the hand in any orientation when a constant vertical force is supplied to the other side of the pantograph. We present several topologies and analyze them based on feasibility of manufacture and ability to provide a near vertical force to the pantograph linkage. Simulations are created using the best topologies and the resulting forces at the hand are reported. The mechanical design of an unpowered (passive) exoskeleton which uses a gas spring mechanism is presented. Additionally, simulations and block-CAD of a powered (active) exoskeleton which uses a motor for the supply of force are presented. The performance of the passive exoskeleton is qualitatively compared with simulations. / Master of Science / A wearable device or exoskeleton is presented which is designed to help a user support a weight of 20 pounds (89~N) at their hand. A pantograph linkage arm exoskeleton provides forces to the hand which are equal to the force provided to the linkage divided by the linkage's ratio. Providing a force to the linkage that is purely vertical will result in a purely vertical force at the hand. Layouts of the exoskeleton components which produce a near-vertical force for the linkage are explored. The more promising layouts are simulated and the forces are compared based on how vertical the forces are. The design of an unpowered exoskeleton is also presented, which uses a gas spring mechanism to provide force. Additionally, simulation results for the unpowered exoskeleton and the basic design and analysis of a powered exoskeleton are presented.