GB1299720A - Apparatus for continuously forming a metal framework - Google Patents

Abstract

1299720 Welding by pressure; making lattice girders O CRISTOFORETTI and G HELL 30 Dec 1969 [13 Jan 1969 6 Dec 1969] 63314/69 Headings B3A and B3R An apparatus, for producing a lattice girder comprising a single upper and two lower longitudinal stringers 2, 3 and lateral struts 4, comprises means for feeding and maintaining the struts to and in welding positions, upper and lower strut/stringer welding means 30, 35, and a reciprocating transporting means 60 for longitudinally moving the girder through the apparatus. The upper welding means 30 (Figs. 2, 4) comprises pairs of parallel hydraulically actuated, spring returned, electrodes 31 having cranked ends and being rotationally adjustable about their longitudinal axes such that said ends of each pair may be adjusted towards and away from each other in the longitudinal direction of the girder. The electrodes are also pivotable about transverse axes to accommodate strut angle. The lower welding means 35 (Figs. 1, 5) comprises hydraulically, pneumatically or electrically actuated plate units 36. Units 38 guide and support the partly formed framework through the lower welding means. The transporting means 60 comprises a reciprocating carriage 62 having a support 61 engageable with the underside of the stringer 2 and one-way acting pawls 63 engageable with the struts 4. As shown, the struts 4 are loaded into hoppers 11 having at their exits rotatable, peripherally slotted drums 12 by which the struts are metered through shoots 14 into magazines 16. Drum operation is controlled by means optically, electrically or mechanically sensing magazine stock. Hydraulically actuated pistons 8 project the struts from the magazines towards a strut clamping device comprising variable angle fixed plates 41 and a double jaw member 42 acted on by a pneumatic or hydraulic cylinder 45 via an inverted wedge 43. In Fig. 6 (not shown), the jaw member 42 is replaced by a quadrilateral linkage (48). In Fig. 7 (not shown), the struts are clamped between fixed inner plates (51) and movable outer plates (52). In Figs. 8, 9 (not shown), the struts are clamped between fixed outer rollers (56) and an upwardly movable wedge (58). In Figs 11, 12 (not shown), the struts fall from metering drums (71), through tubes (73), directly on to a suitable recessed support (75) which after welding is downwardly withdrawn. In Fig. 13 (not shown), the struts are formed from wire which is fed from storage reels (80), through wire straighteners (81), into engagement with a support, the lower ends of the struts being severed from the fed wire by cutters (82). Fail-safe devices (not shown or described) are provided to stop the apparatus in the event of malfunction or strut supply interruption.