GB1286466A - Lockbolt placing apparatus - Google Patents

Abstract

1286466 Riveting AVDEL Ltd 3 Oct 1969 [4 Oct 1968] 47177/68 Heading B3U A lockbolt placing apparatus comprises an hydraulic master piston 11 reciprocable in a master cylinder 12 one side of which is connected to an hydraulic reservoir 25 and both sides of which are connected by hydraulic connections 19, 21 to the opposite sides of a slave cylinder 15 which is connectable to an anvil for swaging the lockbolt collar and in which reciprocates a slave piston 14 connectable to a lockbolt stem gripping device. In operation, the trigger (53) (Fig. 2, not shown) of the tool is depressed to actuate a valve member (48) (Fig. 5, not shown) of a pneumatic valve (46) which allows compressed air to raise a piston 44 and the connected master piston 11. Hydraulic fluid is forced into the slave cylinder 15 via the connection 19 to drive the piston 14 rearwards causing the stem gripping jaws (66) (Fig. 8, not shown) to be retracted and the anvil (61) to be forced over the lockbolt collar. A deficiency of hydraulic fluid is produced in the connection 21 due to the different effective areas of the pistons 11, 14, which deficiency is rectified by fluid being drawn from the reservoir 25 through a non-return valve 27. The fluid is contained in a compressed foam rubber tube 36 which expands to fill up the space in the reservoir 25 occupied by the withdrawal of fluid. When the collar has been swaged into the locking grooves in the stem and the stem has broken, the trigger (53) is released to cause the master piston 11 to move downwards and the slave piston 14 forwards. The pressure in the connection 21 is thereby increased, the high pressure behind the piston 14 allowing the ejector sleeve (73) to pull the anvil (61) off the swaged collar. The excess fluid in the connection 21 is discharged into the reservoir 25 through a pressurized inlet valve 31 which opens at a pressure differential of 1500 p.s.i., the rubber 36 being compressed to accommodate the fluid. The reservoir 25 is designed to absorb the extra excess fluid produced if the slave piston 14 is prevented from moving forwardly due to jamming of the jaws (66).