| 摘要 |
The invention provides a reduced recoil bucking bar and corresponding methods for forming joints with rivets. The bucking bar includes a housing and a driven member movable with respect to the housing. The worker using the bar holds it with the driven member pressed against one end of the rivet. When blows are delivered from the hammer through the rivet to the bar, an appropriate reaction force is generated automatically by mechanisms within the bar. These mechanisms include at least a first pressure chamber and an exhaust port for releasing pressure from the pressure chamber to the atmosphere. By controlling the flow of air through the pressure chamber, the mechanisms within the bucking bar control the forces acting on the driven member during the recoil and rebound motions. Preferred control mechanisms include a second pressure chamber and a movable shuttle. The shuttle is initially biased in a preferred direction by a biasing element in the form of a coil spring. Subsequent movement of the shuttle is dependent upon the characteristics of the hammer blow. Generation of reaction force within the bucking bar is in turn dependent on the position and motion of the shuttle. Preferably, the shuttle acts as part of several valves controlling the flow of pressurized air into and out of the two pressure chambers. A piston fixed to the end of the driven member acts as part of another valve for controlling the flow of pressurized air into the first pressure chamber.
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