| 摘要 |
1,092,475. Blind riveting. GEORGE TUCKER EYELET CO. Ltd. Jan. 28, 1965 [Jan. 29, 1964], No. 3742/65. Heading B3U. A tool for setting tubular rivets by means of a break-off mandrel comprises an hydraulic cylinder 52 containing a piston 112 which is connected to a mandrel-gripping chuck mechanism 86, 88, by a hollow draw rod 78. Hydraulic fluid from a chamber 16 is forced into the cylinder 52 by a piston mounted on a piston rod 22 which also carries the piston 24 of a pneumatic cylinder 2. The rate of flow of fluid into the cylinder 52 is controlled by a metering device including an orifice plate which has a small central hole 44a and also has notches (44b), Fig. 3 (not shown), in its edge. The plate is free to move axially in a housing 36. When fluid is passing to the cylinder 52 the plate moves against a seat 46 which has a central aperture 48 which is larger than the bore 44a but is too small to allow fluid to pass by the notches (44b). When the rivet-setting mandrel breaks at the end of an operation the piston 112 moves suddenly forward and due to the restriction on the flow of fluid to the cylinder 52 there is a drop of pressure in the cylinder 52 which reduces the recoil of the tool and the possibility of damage to the workpiece. The piston 112 is returned by a spring 104 and when fluid is flowing into the chamber 16 the orifice plate moves against a shoulder 39 partly defined by a bore 42 which is of such a size that fluid can flow through the notches (44b) to facilitate the return movement. The tool is controlled by a trigger 130 which through a toggle mechanism operates a tubular member 144. This member pushes down a rubber valve 160 which is normally held against a valve seating by pressure in the air-line, and permits air to flow to the underside of the piston 24. |
