GB1145442A - Fluid pressure power tools - Google Patents

Abstract

1,145,442. Blind riveting; crimping. SCOVILL MFG. CO. 28 Nov., 1967 [30 Nov., 1966; 2 Nov., 1967], No. 54082/67. Headings B3Q and B3U. A fluid-operated power tool comprises a cylinder 10 in which three pistons 26, 30 are slidably mounted in three chambers defined by plates 22. The pistons are spaced by cylindrical spacers 23 and the spacers and pistons are held together by a hollow tie rod 17. One end of the tie rod has a nut 16 screwed thereon which is slidable in a guide 13 mounted on the cylinder by split rings 15. The mandrel of a blind riveting assembly can be secured to the tie rod. In operation compressed air is admitted by a valve in the passage 39 to the annular manifold between the spacers and the tie rod. The fluid flows through gaps 31 between the spacers and recesses 36a, 36b, 36c in the pistons into the chambers. The plates 22 are not secured to the cylinder wall and are forced against split rings 15 by the air. The recesses 36a, 36b, 36c get progressively larger to admit equal quantities of air to each chamber. The rearmost piston abuts a resilient buffer 42 when the mandrel breaks. The valve is then moved so that the chambers may exhaust under spring bias 37. In an alternative embodiment the tool acts leftwards under air pressure and is returned rightwards under spring bias. The tool has a fixed anvil 52 and a crimping or clinching hammer 51. Alternatively the tool may have double-acting pistons and a valve 61 to supply air to either side of the pistons. To move the hammer against the anvil air is supplied through a passage 55 to the annular manifold. To retract the hammer air is supplied along passage 59 to the left of piston 30.