GB1087183A - Improvements in or relating to pneumatic stapling machines - Google Patents

Abstract

1,087,183. Stapling machines. U. MONACELLI. June 8, 1965 [June 10, 1964; March 17, 1965],No. 24302/65. Heading B4C. A pneumatic stapling machine comprises a staple driving piston 9 slidable in a cylinder 10 under the control of a differential valve piston 15 adapted to normally close the open top of the cylinder, a differential valve member 51, 52, 53 being mounted in the valve piston and arranged to open or close exhaust ports 21, 22, 27 communicating with the top of the cylinder. The differential piston 15 is formed with discs 16, 17 having in their periphery sealing rings 58, 59, Fig. 4, for engagement with tapering seats 56, 57, the ports 21, 22 leading into a chamber 23 between the discs; a resilient ring 18<SP>1</SP> is mounted on the differential piston for engagement with the open top of the cylinder 10. A trigger-operated valve 28<SP>1</SP>, 29 controls the flow of compressed air from a reservoir 3 to the differential piston. In operation, air normally acts, via ports 30, 31 in the trigger valve, on the piston 15 to maintain it in the position shown. Upon operation of the trigger valve, the ports 30, 31 are closed and the differential piston is raised via air acting on the disc 17 so as to permit the air to drive the piston 9 on its working stroke; the air in front of the driving piston is forced through a slot 41 into a chamber 42. When the trigger valve is released at the end of the working stroke, the differential piston is urged downwardly to seal the top of the cylinder and the valve 5, 52 is opened so that the piston 9 is moved upwardly by the compressed air trapped in the chamber 42.