GB1222707A - Improvement relating to pneumatic mechanical shoe nailing machines - Google Patents

Abstract

1,222,707. Shoe nailing machines. ZAVODY PRESNEHO STROJIRENSTVI NARODNI PODNIK. 5 Sept., 1968 [8 Sept., 1967], No. 42202/68. Heading B4C. In a shoe nailing machine, a last support comprises a supporting body 2 pivotally mounted on a shaft 29, a push rod 5 having an opening 25 for receiving a centring plug (15) (Fig. 2, not shown) for the last (16) and movable relative to the body by means of a pneumatically operable piston and cylinder 8, 9, an adjustable support (17) for the last mounted on an arm 20, and two mechanisms each including a unidirectional coupling, one mechanism being adapted to lock the push rod against downward movement and the other being adapted to lock the body against clockwise movement. The unidirectional coupling or clutch associated with the push rod includes a part 28 rotatably mounted on the shaft 29 and a second part 35 fixed on the shaft. A rack 26 connected to the push rod engages teeth on the part 28. When the push rod has been moved to a selected position by piston and cylinder 8, 9, a pneumatically operable piston and cylinder 48 is actuated to raise a toothed rack 45 which engages with a toothed member 44 fast on the shaft 29. Upward movement of the rack 45 causes the shaft 29 to rotate and the second part 35 to rotate and wedge rollers 36 against the part 28, thus securely locking the rod 5 against downward movement. The rack 45 may be locked in a raised position by a locking wedge 55 engaging a shoulder 56 on the rack. The wedge is mounted on the piston 54 of a pneumatic piston and cylinder device 51. The mechanism for locking the body 2 against clockwise movement includes a unidirectional coupling similar to that shown in Fig. 3. A toothed member (70<SP>1</SP>) (Fig. 4, not shown) fixed on the shaft 74 is engaged by one arm 70 of a lever 66 which is pivoted by actuation of a pneumatically operable piston and cylinder 61. The unidirectional coupling is mounted on the shaft 74 and the rotatable part has a toothing which engages with a toothed rack 78. Each coupling includes a ring with projections 39 thereon. By appropriate adjustment of a screw 42, a pin 40, fixed on the ring, is moved clockwise (Fig. 3) so as to move the ring and disengage rollers 36.