GB1429201A - Manufacture of welded floos gratings - Google Patents

Abstract

1429201 Making gratings; welding by pressure ESAB Ltd 15 Oct 1973 [16 Oct 1972 19 Sept 1973] 48018/73 Headings B3A B3E and B3R In making a floor grating formed of longitudinal strips 1 on edge with cross-bars 2 welded to the strips, the strips are advanced as a flat array of parallel strips with the sides of the strips in a plane and during advancing the strips are gradually twisted into an on edge position, the on edge strips being fed to a resistance welding station where the cross-bars are welded to the on edge strips. In an embodiment a steel sheet is unwound from a coil 16, Fig. 3, carried by a carriage 14 on a track 18, another carriage 15 carrying another coil 17 being provided to replace the coil 16 when the latter is exhausted, the ends of the coils possibly being welded together. An advancing device 6 pulls the sheet through guiding and straightening rolls 19, 20, 21 and passes it through rotary shears 23 which slit the sheet into narrow strips, the strips passing into a pit 8 where they form a hanging loop. The strips are pulled by a step-by-step advancing mechanism from the pit over a table 9 where distance members engage between the strips and during passage along the table each strip is twisted through 90 degrees into an on edge position by pairs of vertical guide rolls 33. The on edge strips enter the welding station 10 where cross-bars are fed one at a time from a store 35 through a shoot 36, two cross-bars at a time being welded to the strips by an electrode and the assembly being advanced by a pair of pawls operated by a pneumatic cylinder 37 and engaging a cross-bar welded to the strips. At a cutting station 11 shearing means 38 cut the grating into lengths which are moved to the rear of a roller table 12 and removed by a crane 13. Monitoring means 27, 28 signal when the loop deviates from a predetermined length may adjust the rate of advance of the means 6. A platform 41 to bridge the pit during start of the process is provided. To obviate the need for manual twisting of the strips prior to entering the rolls 33, the rolls are replaced by guide fingers 52, 53 which are positioned as in Fig. 5a until the strips have entered between them, as shown, and then they are moved in directions normal to the plane of the strips to bend the strips into the on edge position as shown in Fig. 5b. In a modification guide fingers 57,58, Fig. 6, are combined with an upper guide bar 55 and a lower guide bar 56 movable together and apart by pressure cylinders 59, 60. The strips are pulled through square guide tubes 62 towards the bars 55, 56 and ribs 64, 65 guide the strip leading ends. A ramp 63 on each rib 64 deflects the leading ends upwardly instead of using a sheet which has to be slit into the strips, a number of strips may be fed from separate coils and cross-bars may be provided on both the upper and lower surfaces. An angle or channel iron frame may be provided.