| 摘要 |
1,087,180. Nailing machines. SIGNODE CORPORATION. Nov. 11, 1965 [Dec. 7, 1964], No. 47978/65. Heading B4C. [Also in Division F2] A pneumatically-actuated nailing machine comprises a piston 114 reciprocably mounted in a tapered cylinder 112, valve means 196 for controlling the flow of air to the large end of the cylinder in order to drive the piston on its working stroke and for exhausting the cylinder so that the piston may be returned by compressed air trapped in a chamber 132. The piston is provided with a pair of O-ring seals 124, 128 mounted in grooves 126, 130, the seals being adapted to move inwardly as the piston moves towards the smaller end of the cylinder. In operation, with the machine in the position shown, compressed air is fed from a reservoir 190 through a port 212 thereby maintaining the valve 196 in a position in which the space 188 above the piston is exhausted. Upon actuating a trigger 216 a ball valve 224 closes the port 212 so that the valve 196 closes the exhaust port 218 and opens a port 194 so that the piston is driven on its working stroke. As the piston starts to travel downwardly air also passes into the chamber 132 via a non-return valve 150, Fig. 10, the air being compressed in the chamber during the working stroke in view of the reduction in the volume of the chamber. At the end of the stroke, the trigger is released and the piston is returned to its upper position by the compressed air in the chamber. |
